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Unlabelled: As part of a search for optimal conditions for radioimmunotherapy of lymphoma, rituximab was labeled with 2 different specific activities of 131I and immunoreactivity was comparatively measured., Methods: Labeling was performed with chloramine T using as starting conditions 185 MBq of 131I per 1 mg and per 5 mg of antibody for labelings A and B, respectively. Six comparative labelings were performed over a period of 10 mo with similar efficacy and purified by anion-exchange chromatography. Immunoreactivity was determined immediately after labeling in parallel assays using different concentrations of fresh Raji and Daudi cells. Results were compared at maximal observed specific binding on 10(7) cells and after extrapolation to infinite antigen excess. A statistical analysis was performed to predict the frequency of radiolabeled mono- and polyiodinated antibodies: First, a gaussian distribution predicted the number of iodine atoms per antibody in labelings A and B, respectively; then, the radiolabeling probability was developed according to the Newton binome., Results: Final radiochemical purity was >98.4% for all labelings. The final mean specific activities were 169.7 MBq/mg and 32.8 MBq/mg, corresponding to 0.87 and 0.17 iodine atoms per antibody in labelings A and B, respectively. Labeling B showed a significantly higher immunoreactivity than did labeling A, the mean relative increase in binding being > or =28% for both Raji cells and Daudi cells. The predictive statistical analysis indicated that 57.3% and 15.4% of radiolabeled antibodies in labelings A and B, respectively, were polyiodinated., Conclusion: The low specific activity of 131I-rituximab allowed preservation of a high immunoreactivity and correlated with the prediction of a low percentage of polyiodinated radiolabeled antibodies.

Data quality and scoring assumptions for the SF-36 Health Survey were evaluated among the elderly and disabled, using 1998 Cohort I baseline Medicare HOS data (n=177,714). Missing data rates were low, and scoring assumptions were met. Internal consistency reliability was 0.83 to 0.93 for the eight scales and 0.94 and 0.89, respectively, for the physical (PCS) and mental (MCS) component summary measures. Results declined with increased risk factors (e.g., older age, more chronic conditions), but were well above accepted standards for all subgroups. These findings support using standard algorithms for scoring the SF-36 in the HOS and subgroup analyses of HOS data.

Intratumoural (i.t.) injection of radio-iododeoxyuridine (IdUrd), a thymidine (dThd) analogue, is envisaged for targeted Auger electron- or beta-radiation therapy of glioblastoma. Here, biodistribution of [(125)I]IdUrd was evaluated 5 hr after i.t. injection in subcutaneous human glioblastoma xenografts LN229 after different intravenous (i.v.) pretreatments with fluorodeoxyuridine (FdUrd). FdUrd is known to block de novo dThd synthesis, thus favouring DNA incorporation of radio-IdUrd. Results showed that pretreatment with 2 mg/kg FdUrd i.v. in 2 fractions 0.5 hr and 1 hr before injection of radio-IdUrd resulted in a mean tumour uptake of 19.8% of injected dose (% ID), representing 65.3% ID/g for tumours of approx. 0.35 g. Tumour uptake of radio-IdUrd in non-pretreated mice was only 4.1% ID. Very low uptake was observed in normal nondividing and dividing tissues with a maximum concentration of 2.9% ID/g measured in spleen. Pretreatment with a higher dose of FdUrd of 10 mg/kg prolonged the increased tumour uptake of radio-IdUrd up to 5 hr. A competition experiment was performed in FdUrd pretreated mice using i.t. co-injection of excess dThd that resulted in very low tumour retention of [(125)I]IdUrd. DNA isolation experiments showed that in the mean >95% of tumour (125)I activity was incorporated in DNA. In conclusion, these results show that close to 20% ID of radio-IdUrd injected i.t. was incorporated in tumour DNA after i.v. pretreatment with clinically relevant doses of FdUrd and that this approach may be further exploited for diffusion and therapy studies with Auger electron- and/or beta-radiation-emitting radio-IdUrd., (Copyright 2004 Wiley-Liss, Inc.)

Background and Methods: 5-Iodo-2'-deoxyuridine (IdUrd) radiolabelled with the positron emitter I or with the gamma and Auger electron emitters I or I has been proposed for cancer diagnosis and therapy. We modified the synthesis to reliably obtain [I]IdUrd and [I]IdUrd by using an Iodogen supported destannylation reaction of 5-(tri-n-butylstannyl)-2'-deoxyuridine (Bu3SndUrd) which meets the requirements for good laboratory practice (GLP) and good clinical practice (GCP). A method of purification was developed to eliminate by-products as well as any unreacted starting material., Results: [I]IdUrd, which originated from a trace of iodide in the Bu3SndUrd precursor, was identified as the unknown by-product reported for this method. This trace could be eliminated by modified purification of Bu3SndUrd. Stabilization of pH was essential for unequivocal identification of radiolabelled IdUrd and possible degradation products in the different systems tested for quality control. Biodistribution in tumour bearing nude mice was measured as early as 3 and 6 h after i.v. injection of [I]IdUrd. This compound showed high and specific activity uptake in tumour and dividing tissues when combined with 5-fluoro-2'-deoxyuridine pre-treatment. Uptake was specifically inhibited by injection of excess thymidine.

Objective: To compare simulated short-form and computerized adaptive testing (CAT) scores to scores obtained from complete item sets for each of the 3 domains of the Activity Measure for Post-Acute Care (AM-PAC)., Design: Prospective study., Setting: Six postacute health care networks in the greater Boston metropolitan area, including inpatient acute rehabilitation, transitional care units, home care, and outpatient services., Participants: A convenience sample of 485 adult volunteers who were receiving skilled rehabilitation services., Interventions: Not applicable., Main Outcome Measures: Inpatient and community-based short forms and CAT applications were developed for each of 3 activity domains (physical & mobility, personal care & instrumental, applied cognition) using item pools constructed from new items and items from existing postacute care instruments., Results: Simulated CAT scores correlated highly with score estimates from the total item pool in each domain (4- and 6-item CAT r range,.90-.95; 10-item CAT r range,.96-.98). Scores on the 10-item short forms constructed for inpatient and community settings also provided good estimates of the AM-PAC item pool scores for the physical & movement and personal care & instrumental domains, but were less consistent in the applied cognition domain. Confidence intervals around individual scores were greater in the short forms than for the CATs., Conclusions: Accurate scoring estimates for AM-PAC domains can be obtained with either the setting-specific short forms or the CATs. The strong relationship between CAT and item pool scores can be attributed to the CAT's ability to select specific items to match individual responses. The CAT may have additional advantages over short forms in practicality, efficiency, and the potential for providing more precise scoring estimates for individuals.

Objective: To develop a comprehensive set of short forms using item response theory (IRT) and item pooling procedures for the purpose of monitoring postacute care functional recovery., Design: Prospective study., Setting: Six postacute health care networks in the greater Boston area, including inpatient acute rehabilitation, transitional care units, home care, and outpatient services., Participants: A convenience sample of 485 adult volunteers who were currently receiving skilled rehabilitation services., Interventions: Not applicable., Main Outcome Measures: We developed a set of 6 short forms across 3 activity domains from new items and items from existing postacute care instruments., Results: Inpatient- and community-based short forms were developed for each of 3 activity domains: physical & movement, applied cognition, and personal care & instrumental. Items were selected for inclusion on the short forms to maximize content coverage and information value of items across the range of content and to minimize ceiling and floor effects. We were able to match the distribution of sample scores with very good item precision for 1 of the constructs (physical & movement); the other 2 domains (personal care & instrumental, applied cognition) were more challenging because of the variability in patient recovery and ceiling effects., Conclusions: ITR methods and item pooling procedures were valuable in developing paired sets of short-form instruments for inpatient and community rehabilitation that provided estimates of functioning along a common metric for use across postacute care settings.

Background: Asthma guidelines indicate that the goal of treatment should be optimum asthma control. In a busy clinic practice with limited time and resources, there is need for a simple method for assessing asthma control with or without lung function testing., Objectives: The objective of this article was to describe the development of the Asthma Control Test (ACT), a patient-based tool for identifying patients with poorly controlled asthma., Methods: A 22-item survey was administered to 471 patients with asthma in the offices of asthma specialists. The specialist's rating of asthma control after spirometry was also collected. Stepwise regression methods were used to select a subset of items that showed the greatest discriminant validity in relation to the specialist's rating of asthma control. Internal consistency reliability was computed, and discriminant validity tests were conducted for ACT scale scores. The performance of ACT was investigated by using logistic regression methods and receiver operating characteristic analyses., Results: Five items were selected from regression analyses. The internal consistency reliability of the 5-item ACT scale was 0.84. ACT scale scores discriminated between groups of patients differing in the specialist's rating of asthma control (F = 34.5, P <.00001), the need for change in patient's therapy (F = 40.3, P <.00001), and percent predicted FEV(1) (F = 4.3, P =.0052). As a screening tool, the overall agreement between ACT and the specialist's rating ranged from 71% to 78% depending on the cut points used, and the area under the receiver operating characteristic curve was 0.77., Conclusion: Results reinforce the usefulness of a brief, easy to administer, patient-based index of asthma control.

The objective of this study was to document the disease burden associated with moderate to severe plaque psoriasis, and assess the impact of efalizumab psoriasis treatment in improving patient-reported outcomes. This included analysis of patient-reported dermatology-related quality of life (DRQL) and psoriasis symptom scores among patients with moderate to severe psoriasis participating in three phase III, randomized, double-blinded, parallel-group, placebo-controlled, multi-center clinical trials conducted to evaluate the efficacy and safety of efalizumab. A total of 1,242 patients with moderate to severe psoriasis treated either with efalizumab 1.0 mg/kg/wk or placebo were followed for 12 weeks. DRQL and psoriasis symptom severity were assessed at baseline (pre-treatment) and at the end of the first treatment phase (12 weeks). DRQL was measured using the Dermatology Life Quality Index (DLQI). Symptoms were measured using the Psoriasis Symptom Assessment (PSA) and an Itch scale. Disease burden was assessed at baseline by examining responses to individual questions of the DLQI, PSA, and Itch patient-reported outcome measures. The impact of treatment on disease burden was assessed over a 12-week double-blind study period by comparing changes in DLQI, PSA, and Itch scale scores between the active treatment and placebo groups. Patient-reported outcomes were also assessed during a 12-week extended treatment phase. Prior to treatment, the responses to DLQI and PSA items revealed significant disease burden. Greater than 90% of patients reported being embarrassed or self conscious because of their skin, 53% reported that their skin prevented them from working or studying. and 98% reported that scaling and itching was bothersome. Compared to placebo-treated patients, efalizumab-treated patients showed significant improvement in patient-reported outcomes, reducing the limitations and burden associated with moderate to severe psoriasis within each of the three studies, as measured by DLQI (p<0.001), PSA-Severity (p<0.001), PSA-Frequency (p<0.001), and Itch (p<0.001) scores. Across all measures, the proportion of patients that improved on both statistical and clinical criteria for meaningful improvement was at least twofold greater among efalizumab-treated patients than in placebo-treated patients. The benefit of efalizumab was maintained over the course of an additional 12 weeks during an extended treatment phase. In conclusion, patients with moderate to severe plaque psoriasis reported significant DRQL burden and symptom severity at baseline, but efalizumab significantly improved patient-reported DRQL and reduced the frequency and severity of psoriasis symptoms during 12-week double-blind and 12-week extended treatment periods.

Background: Migraine and other severe headaches can cause suffering and reduce functioning and productivity. Patients are the best source of information about such impact., Objective: To develop a new short form (HIT-6) for assessing the impact of headaches that has broad content coverage but is brief as well as reliable and valid enough to use in screening and monitoring patients in clinical research and practice., Methods: HIT-6 items were selected from an existing item pool of 54 items and from 35 items suggested by clinicians. Items were selected and modified based on content validity, item response theory (IRT) information functions, item internal consistency, distributions of scores, clinical validity, and linguistic analyses. The HIT-6 was evaluated in an Internet-based survey of headache sufferers (n = 1103) who were members of America Online (AOL). After 14 days, 540 participated in a follow-up survey., Results: HIT-6 covers six content categories represented in widely used surveys of headache impact. Internal consistency, alternate forms, and test-retest reliability estimates of HIT-6 were 0.89, 0.90, and 0.80, respectively. Individual patient score confidence intervals (95%) of app. +/-5 were observed for 88% of all respondents. In tests of validity in discriminating across diagnostic and headache severity groups, relative validity (RV) coefficients of 0.82 and 1.00 were observed for HIT-6, in comparison with the Total Score. Patient-level classifications based in HIT-6 were accurate 88.7% of the time at the recommended cut-off score for a probability of migraine diagnosis. HIT-6 was responsive to self-reported changes in headache impact., Conclusions: The IRT model estimated for a 'pool' of items from widely used measures of headache impact was useful in constructing an efficient, reliable, and valid 'static' short form (HIT-6) for use in screening and monitoring patient outcomes.

Background: While item response theory (IRT) offers many theoretical advantages over classical test theory in the construction and scoring of patient based measures of health few studies compare scales constructed from both methodologies head to head., Objective: Compare the responsiveness to treatment of migraine specific scales scored using summated rating scale methods vs. IRT methods., Methods: The data came from three clinical studies of migraine treatment that used the Migraine Specific Quality of Life Questionnaire (MSQ). Five methods of quantifying responsiveness were used to evaluate and compare changes from pre- to post-treatment in MSQ scales scored using Likert and IRT scaling methods., Results: Changes in all MSQ scale scores from pre- to post-treatment were highly significant in all three studies. A single index scored from the MSQ using IRT methods was determined to be more responsive than any one of the MSQ subscales across the five methods used to quantify responsiveness. Across 13 of the 15 tests (5 responsiveness methods * 3 studies) conducted, the single index scored from the MSQ using IRT methods was the most responsive measure., Conclusions: IRT methods increased the responsiveness of the MSQ to the treatment of migraine. The results agree with the psychometric evidence that suggest that it is feasible to score a single index from the MSQ using IRT methods. This approach warrants further testing with other measures of migraine impact.

Background: Measurement of headache impact is important in clinical trials, case detection, and the clinical monitoring of patients. Computerized adaptive testing (CAT) of headache impact has potential advantages over traditional fixed-length tests in terms of precision, relevance, real-time quality control and flexibility., Objective: To develop an item pool that can be used for a computerized adaptive test of headache impact., Methods: We analyzed responses to four well-known tests of headache impact from a population-based sample of recent headache sufferers (n = 1016). We used confirmatory factor analysis for categorical data and analyses based on item response theory (IRT)., Results: In factor analyses, we found very high correlations between the factors hypothesized by the original test constructers, both within and between the original questionnaires. These results suggest that a single score of headache impact is sufficient. We established a pool of 47 items which fitted the generalized partial credit IRT model. By simulating a computerized adaptive health test we showed that an adaptive test of only five items had a very high concordance with the score based on all items and that different worst-case item selection scenarios did not lead to bias., Conclusion: We have established a headache impact item pool that can be used in CAT of headache impact.

Background: Item response theory (IRT) is a powerful framework for analyzing multiitem scales and is central to the implementation of computerized adaptive testing., Objectives: To explain the use of IRT to examine measurement properties and to apply IRT to a questionnaire for measuring migraine impact--the Migraine Specific Questionnaire (MSQ)., Methods: Data from three clinical studies that employed the MSQ-version 1 were analyzed by confirmatory factor analysis for categorical data and by IRT modeling., Results: Confirmatory factor analyses showed very high correlations between the factors hypothesized by the original test constructions. Further, high item loadings on one common factor suggest that migraine impact may be adequately assessed by only one score. IRT analyses of the MSQ were feasible and provided several suggestions as to how to improve the items and in particular the response choices. Out of 15 items, 13 showed adequate fit to the IRT model. In general, IRT scores were strongly associated with the scores proposed by the original test developers and with the total item sum score. Analysis of response consistency showed that more than 90% of the patients answered consistently according to a unidimensional IRT model. For the remaining patients, scores on the dimension of emotional function were less strongly related to the overall IRT scores that mainly reflected role limitations. Such response patterns can be detected easily using response consistency indices. Analysis of test precision across score levels revealed that the MSQ was most precise at one standard deviation worse than the mean impact level for migraine patients that are not in treatment. Thus, gains in test precision can be achieved by developing items aimed at less severe levels of migraine impact., Conclusions: IRT proved useful for analyzing the MSQ. The approach warrants further testing in a more comprehensive item pool for headache impact that would enable computerized adaptive testing.

Objective: To evaluate the feasibility of computerized adaptive testing (CAT) and the reliability and validity of CAT-based estimates of headache impact scores in comparison with 'static' surveys., Methods: Responses to the 54-item Headache Impact Test (HIT) were re-analyzed for recent headache sufferers (n = 1016) who completed telephone interviews during the National Survey of Headache Impact (NSHI). Item response theory (IRT) calibrations and the computerized dynamic health assessment (DYNHA) software were used to simulate CAT assessments by selecting the most informative items for each person and estimating impact scores according to pre-set precision standards (CAT-HIT). Results were compared with IRT estimates based on all items (total-HIT), computerized 6-item dynamic estimates (CAT-HIT-6), and a developmental version of a 'static' 6-item form (HIT-6-D). Analyses focused on: respondent burden (survey length and administration time), score distributions ('ceiling' and 'floor' effects), reliability and standard errors, and clinical validity (diagnosis, level of severity). A random sample (n = 245) was re-assessed to test responsiveness. A second study (n = 1103) compared actual CAT surveys and an improved 'static' HIT-6 among current headache sufferers sampled on the Internet. Respondents completed measures from the first study and the generic SF-8 Health Survey; some (n = 540) were re-tested on the Internet after 2 weeks., Results: In the first study, simulated CAT-HIT and total-HIT scores were highly correlated (r = 0.92) without 'ceiling' or 'floor' effects and with a substantial reduction (90.8%) in respondent burden. Six of the 54 items accounted for the great majority of item administrations (3603/5028, 77.6%). CAT-HIT reliability estimates were very high (0.975-0.992) in the range where 95% of respondents scored, and relative validity (RV) coefficients were high for diagnosis (RV = 0.87) and severity (RV = 0.89); patient-level classifications were accurate 91.3% for a diagnosis of migraine. For all three criteria of change, CAT-HIT scores were more responsive than all other measures. In the second study, estimates of respondent burden, item usage, reliability and clinical validity were replicated. The test-retest reliability of CAT-HIT was 0.79 and alternate forms coefficients ranged from 0.85 to 0.91. All correlations with the generic SF-8 were negative., Conclusions: CAT-based administrations of headache impact items achieved very large reductions in respondent burden without compromising validity for purposes of patient screening or monitoring changes in headache impact over time. IRT models and CAT-based dynamic health assessments warrant testing among patients with other conditions.

Background: Migraine headaches have been shown to have substantial personal and societal implications. Health-related quality of life (HRQOL) assessments of migraineurs have been used to monitor and evaluate patient- and population-based outcomes, and to evaluate effectiveness and responsiveness to treatment. In this paper, we test a new, even shorter generic health survey, the SF-8 Health Survey (SF-8), an alternate form that uses one question to measure each of the eight SF-36 Health Survey (SF-36) domains, in a sub-sample of migraine sufferers., Methods: Data from 7557 participants surveyed via the Internet and mail were used to document the burden of migraine on HRQOL and to compare the relative burden of migraine with other chronic conditions using the SF-8., Results: Migraineurs' HRQOL is similar to those with congestive heart failure, hypertension and diabetes, and is better than those with depression. Migraine sufferers experience better physical health and worse mental health (MH) than those with osteoarthritis. Results support prior research indicating that the burden of migraine on functional health and well-being is considerable and comparable to other chronic conditions known to have substantial impact on HRQOL., Conclusions: The SF-8 may provide a more practical and efficient method to describe the burden of migraine in population studies.

Background: Item response theory (IRT) scoring of health status questionnaires offers many advantages. However, to ensure 'backwards comparability' and to facilitate interpretations of results, we need the ability to express the IRT score in the metrics of the traditional scales., Objectives: To develop procedures to calibrate IRT-based scores on the Headache Impact Test (HIT) into the metrics of the traditional headache scales. To assess the degree to which the calibrated HIT scores agree with the observed traditional scores and lead to the same conclusions in group comparisons., Methods: We used telephone interview data (n = 1016) and Internet data (n = 1103) from general population surveys of recent headache sufferers. Analyses were conducted in four steps: (1) develop IRT models for all items, (2) for each IRT score level, calculate the expected score on each of the traditional scales (calibration), (3) adjust this calibrated score for measurement error in the IRT score, (4) for each of the traditional scales, assess agreement between calibrated HIT scores and observed scores using intraclass correlation (ICC) and evaluate the agreement of mean scores and the relative validity (RV) in discriminating among groups differing in migraine diagnosis, headache severity, and change in impact over time., Results: For the traditional categorical questionnaire items (the Migraine Specific Questionnaire (MSQ) and the Headache Disability Inventory (HDI)) the calibrated HIT agreed with the observed traditional scores: ICC's were between 0.80 and 0.94. In RV analyses the maximum mean difference between the observed and expected scores was 1.7 points on a 0-100 scale for comparisons at one point in time. Analyses of change over time and analyses calibrating scores from the fixed-form HIT-6 to the metric of other questionnaires were also satisfactory although less precise. Analysis of non-standard questionnaire items (e.g. On how many days in the past 3 months did you have a headache, from the HIMQ and the MIDAS) required special IRT models. Agreement was less good: ICC's were between 0.56 and 0.61 and the maximum mean differences were 2.9 (on a 0-270 scale) and 3.8 (on a 0-450 scale) in RV analyses at one point in time. The ability of the calibrated scale scores to discriminate between groups was at least as good as the ability of the observed sum scales and often remarkably better., Conclusion: The theoretical advantage of IRT models in scale calibration is supported by our results. This approach to achieving comparability of new and widely-used scales and accelerating the accumulation of interpretation guidelines based on previous work warrant testing for measures of other generic and disease-specific concepts.

Unlabelled: The study aim was to assess the safety, biodistribution, tissue kinetics, and tumor uptake of the (99m)Tc-labeled neurotensin (NT) analog NT-XI., Methods: Four patients presenting ductal pancreatic adenocarcinoma were studied with (99m)Tc-NT-XI. Patients were followed by scintigraphy up to 4 h and by continued blood and urinary sampling until surgery 18-22 h after injection. Surgical tissue samples were analyzed for radioactivity uptake and NT receptor expression., Results: No side effects were observed on injection of (99m)Tc-NT-XI. Blood biologic half-lives alpha and beta were 35 min (range, 17-62 min) and 230 min (range, 107-383 min), respectively. Repeated whole-body scintigraphy performed in 2 patients showed a single exponential decrease of whole-body activity with half-lives of 101 and 232 min. Tracer elimination was mainly renal, with 92% and 98% of activity counted in urine in the first 20 h. Kidney, liver, spleen, and bone marrow activity uptake was observed in all patients. Tumor was not visualized in the first 3 patients but could be localized by tomoscintigraphy in the pancreas head region of patient 4. In vitro tissue analysis showed high expression of NT receptor in the tumor of patient 4, correlated with the highest tumor radioactivity uptake and the highest tumor-to-fat radioactivity ratio. In vitro receptor expression was also positive in a second patient having a tumor characterized by very low cellularity; however, the remaining 2 tumors lacked NT receptor expression., Conclusion: Injection of (99m)Tc-NT-XI was well tolerated. The in vivo tumor uptake appeared specific as it was observed in the 1 patient with a pancreatic tumor that expressed high amounts of NT receptor. The results are compatible with preclinical animal results and in favor of further development of radiolabeled NT analogs for diagnosis or therapy of cancer.

Analyses of cognitive aspects of survey methodology (CASM) and psychometric analysis are two methods that are able to complement each other. We use concrete examples to illustrate how psychometric analyses can test hypotheses from CASM. The psychometrics framework recognizes that survey responses are affected by other factors than the concept being assessed, for example by cognitive factors and processes. Such factors are subsumed under the concept of measurement error. Possible sources of measurement error can be tested, e.g. by randomized experiments. A standard way to reduce measurement error is to ask several questions about the same concept and combine the answers into a multi-item scale that is more precise than the individual items. Techniques like structural equation models use the item correlations to assess the magnitude of measurement error and to test the assumptions behind the multi-item scale, e.g. the effect of common response choices and item time frames. A central problem in modern psychometrics is how to model the mapping of the continuous latent variable onto the item response choice categories. This is achieved by threshold models (e.g. item response models and structural equation models for categorical data). These models can, for example, analyze the impact of mode of administration, test whether the items function in the same way for all people (measurement invariance/differential item functioning) and examine the consistency of responses from any single person. Such analyses provide new possibilities for combining psychometrics and cognitive methods.

During sexual reproduction in most animals, oocytes arrest in meiotic prophase and resume meiosis (meiotic maturation) in response to sperm or somatic cell signals. Despite progress in delineating mitogen-activated protein kinase (MAPK) and CDK/cyclin activation pathways involved in meiotic maturation, it is less clear how these pathways are regulated at the cell surface. The Caenorhabditis elegans major sperm protein (MSP) signals oocytes, which are arrested in meiotic prophase, to resume meiosis and ovulate. We used DNA microarray data and an in situ binding assay to identify the VAB-1 Eph receptor protein-tyrosine kinase as an MSP receptor. We show that VAB-1 and a somatic gonadal sheath cell-dependent pathway, defined by the CEH-18 POU-class homeoprotein, negatively regulate meiotic maturation and MAPK activation. MSP antagonizes these inhibitory signaling circuits, in part by binding VAB-1 on oocytes and sheath cells. Our results define a sperm-sensing control mechanism that inhibits oocyte maturation, MAPK activation, and ovulation when sperm are unavailable for fertilization. MSP-domain proteins are found in diverse animal taxa, where they may regulate contact-dependent Eph receptor signaling pathways.

In tissue engineering, degradable or non-degradable polymer matrices can act as cell-carrier-scaffolds. Cell adhesion and growth on these scaffolds can be promoted by immobilizing extracellular matrix proteins. Therefore, in this study, polymer poly(ethylene terephthalate) (PET) films were surface modified by graft polymerization of acrylic acid, to subsequently allow collagen (types I and III) immobilization and human smooth muscle cell expansion. The surfaces of PET were activated by plasma, followed by acrylic acid graft polymerization, resulting in covalently bound brushes, containing an average of either 0.22+/-0.1 or 5.93+/-0.87 microg/cm2 of poly(acrylic acid) (PAA). Subsequent electrostatic adsorption of collagen gave a surface concentration of 4.96 and 17.2 microg/cm2, respectively, as determined using radiolabelled 125I collagen. Both PET films grafted with 0.22 microg/cm2 of PAA with or without adsorbed collagen were apt for smooth muscle cell adhesion and proliferation. However, films grafted with 5.93 microg/cm2 were not. PAA-grafted PET films, onto which serum proteins of the culture medium adsorbed spontaneously, proved to be better matrices than films on which collagen has been immobilized. It, therefore, can be speculated that other serum proteins are more important than collagen for the human smooth muscle cell adhesion and growth on surface-modified polymer matrices.

Objective: To document the burden of early rheumatoid arthritis (RA) on health-related quality of life (HQL) and compare changes in HQL across 2 treatments., Study Design: Analysis of HQL scores among patients enrolled in a multicenter, double-blind, randomized control trial of early RA treatment., Patients and Methods: A total of 424 patients with early RA were randomized to 1 of 2 treatment groups: etanercept or methotrexate. Patients were treated and followed for 52 weeks. Health-related quality of life was assessed before and throughout treatment using the Medical Outcomes Study Short Form 36 Health Survey (SF-36) and the Health Assessment Questionnaire (HAQ). The HQL burden of RA was established by comparing SF-36 scale scores to general US population norms. The impact of treatment on HQL was determined by comparing scores on both SF-36 and HAQ scales., Results: Before treatment, RA patients showed significant decrements in scores on all SF-36 scales and summary measures in comparison with age- and sex-matched general US population norms, multivariate analysis of variance (MANOVA) F(8,2815) = 204.6, P < .0001. After 52 weeks of treatment, 7 of 8 SF-36 scales and the physical summary measure remained significantly below the general US population norm, MANOVA F(8,2815) = 41.9, P < .0001. Patients randomized to etanercept showed significantly better HQL improvement earlier in treatment than patients randomized to methotrexate on the SF-36 physical summary, MANOVA F(10,4230) = 6.1, P< .0001, the SF-36 arthritis-specific health index, MANOVA F(10,4230) = 8.5, P < .0001, and the HAQ, MANOVA F(10,4230) = 14.7, P < .0001. At 52 weeks, there were no significant differences between treatment groups., Conclusions: Rheumatoid arthritis places tremendous disease burden on patients' HQL. Successful treatment of early RA improved HQL. Etanercept showed a rapid HQL response.

Caenorhabditis elegans oocytes, like those of most animals, arrest during meiotic prophase. Sperm promote the resumption of meiosis (maturation) and contraction of smooth muscle-like gonadal sheath cells, which are required for ovulation. We show that the major sperm cytoskeletal protein (MSP) is a bipartite signal for oocyte maturation and sheath contraction. MSP also functions in sperm locomotion, playing a role analogous to actin. Thus, during evolution, MSP has acquired extracellular signaling and intracellular cytoskeletal functions for reproduction. Proteins with MSP-like domains are found in plants, fungi, and other animals, suggesting that related signaling functions may exist in other phyla.

Background and Aims: To investigate the importance of lipase on gastric functions, we studied the effects of orlistat, a potent and specific inhibitor of lipase, on postprandial gastric acidity and gastric emptying of fat., Methods: Fourteen healthy volunteers participated in a double blind, placebo controlled, randomised study. In a two way cross over study with two test periods of five days, separated by at least 14 days, orlistat 120 mg three times daily or placebo was given with standardised daily meals. In previous experiments we found that this dose almost completely inhibited postprandial duodenal lipase activity. Subjects underwent 28 hour intragastric pH-metry on day 4, and a gastric emptying study with a mixed meal (800 kcal) labelled with (999m)Tc sulphur colloid (solids) and (111In)thiocyanate (fat) on day 5. Gastric pH data were analysed for three postprandial hours and the interdigestive periods., Results: Orlistat inhibited almost completely (by 75%) lipase activity and accelerated gastric emptying of both the solid (by 52%) and fat (by 44%) phases of the mixed meal (p<0.03). Orlistat increased postprandial gastric acidity (from a median pH of 3.3 to 2.7; p<0.01). Postprandial cholecystokinin release was lower with orlistat (p<0.03)., Conclusion: Lipase has an important role in the regulation of postprandial gastric acid secretion and fat emptying in humans. These effects might be explained by lipolysis induced release of cholecystokinin.

Objective: The reliability, validity, and feasibility of the routine use of a generic health status instrument, the Short-Form-36 Health Survey (SF-36), were examined in a psychiatric outpatient clinic of a general hospital., Methods: The sample comprised 411 patients referred to an outpatient psychiatry department between April 1994 and March 1995. They filled out the SF-36 along with their admission forms. Scores and reports were generated, and the results were returned to the charts and used at weekly clinical conference discussions. Feasibility was evaluated using subjective and objective data on administration of the instrument, its psychometric properties, and costs. Results from the outpatient psychiatry patients were compared with those from patients scheduled for elective surgery and a healthy normative sample., Results: Routine administration of the SF-36 was successfully achieved with minimal resistance from staff and patients. The SF-36 provided reliable and valid data. As predicted, patients with emotional disorders scored lower, indicating more impairment, on scales measuring mental health than did the elective surgery patients and the normative sample. However, the psychiatric patients' scores on the physical health scale were lower than clinicians expected. Compared with the elective surgery patients, the psychiatric patients were less impaired on only the physical functioning and bodily pain scales; no difference was found between the two groups in role functioning due to physical problems., Conclusions: Routine use of the SF-36 in a general hospital psychiatric outpatient clinic was feasible, and the results were reliable, valid, and helpful to clinicians. Psychiatric patients' significantly lower scores in physical health and social and role functioning provided additional information about their difficulties.

The Polo-like kinases are key regulatory molecules required during the cell cycle for the successful completion of mitosis. We have cloned a C. elegans homolog of the Drosophila melanogaster polo gene (designated plk-1 for C. elegans polo-like kinase-1) and present the subcellular localization of the PLK-1 protein during the meiotic and mitotic cell cycles in C. elegans oocytes and embryos, respectively. Disruption of PLK-1 expression by RNA-mediated interference (RNAi) disrupts normal oocyte and embryonic development. Inspection of oocytes revealed a defect in nuclear envelope breakdown (NEBD) before ovulation. This defect in NEBD was also observed in oocytes that were depleted of the cyclin-dependent kinase NCC-1 (C. elegans homolog of Cdc2). The plk-1 RNAi oocytes were fertilized; however the resulting embryos were unable to separate their meiotic chromosomes or form and extrude polar bodies. These defects led to embryonic arrest as single cells. genesis 26:26-41, 2000. Published 2000 Wiley-Liss, Inc.

A wee1 homolog, wee-1.1, is expressed in both a temporally and spatially restricted pattern during early Caenorhabditis elegans embryogenesis, and is undetectable throughout the remainder of embryogenesis. The wee-1.1 message appears to be zygotically expressed in the somatic founder cell E of the 12-cell embryo. This expression disappears when the E blastomere divides for the first time. The wee-1.1 message then appears transiently in the nuclei of the eight great-granddaughter cells of the AB somatic founder cell, just before these cells divide in the 16-cell embryo. Following this division, the wee-1.1 mRNA is no longer detectable throughout the remainder of embryogenesis. The expression of wee-1.1 in the E blastomere and in the AB progeny appears to be restricted to nuclei in prophase and metaphase of the cell cycle. Analysis of the wee-1.1 mRNA expression pattern in maternal-effect lethal mutants suggests that this expression pattern is restricted to cells of the E and AB fates in the early embryo. This mRNA expression pattern is restricted to a 10-15-min span of embryonic development and may be regulating the timing of crucial cell divisions at this early stage of development.

The CDC25 dual-specificity phosphatase family has been shown to play a key role in cell cycle regulation. The phosphatase activity of CDC25 drives the cell cycle by removing inhibitory phosphates from cyclin-dependent kinase/cyclin complexes. Although the regulation of CDC25 phosphatase activity has been elucidated both biochemically and genetically in other systems, the role of this enzyme during development is not well understood. To examine the expression pattern and function of CDC25 in Caenorhabditis elegans, we characterized a cdc25 homolog, cdc-25.1, during early embryonic development. The CDC-25.1 protein localizes to oocytes, embryonic nuclei, and embryonic cortical membranes. When the expression of CDC-25.1 was disrupted by RNA-mediated interference, the anterior cortical membrane of fertilized eggs became very fluid during meiosis and subsequent mitotic cell cycles. Mispositioning of the meiotic spindle, defects in polar body extrusion and chromosome segregation, and abnormal cleavage furrows were also observed. We conclude that CDC-25.1 is required for a very early developmental process-the proper completion of meiosis prior to embryogenesis., (Copyright 1999 Academic Press.)

In the final analysis, outcomes management is about changing behavior, specifically in the occupational and environmental health practitioner's communication process and practice patterns and in the workers' prevention and compliance behavior. Outcomes management is also about quantifying results, establishing occupational and environmental health performance benchmarks, developing a best practices model and asking even more questions. As health care embraces the use of outcomes in evaluating its effectiveness, similar developments can be anticipated in occupational and environmental health. While occupational and environmental health outcomes management is still in its infancy, nurses in the workplace are well positioned to "shape it" into a useful tool that meets the needs of all the various practice settings. As nurses in the workplace begin to evaluate, report, and benchmark results, measurement tools will be refined, data bases will grow and new, useful benchmarks will be established. Because occupational and environmental health programs usually operate as part of a larger business unit, nurses in the workplace are continually faced with the challenge of ensuring that corporate programs including workers' compensation, health and disability benefit programs, vaccination programs, injury prevention, and health promotion or wellness programs are delivered in an efficient and cost-effective manner and that the expected outcomes are achieved. Effective outcomes management programs are the vehicles to effective goal achievement.

Bone and joint infections can occur as the consequence of a wide variety of systemic diseases. Disseminated fungal and mycobacterial infections, hepatitis, syphilis, gonorrhea, Lyme disease, and AIDS can all have osteoarticular manifestations. A thorough knowledge of the wide range of potential pathogens is key to establishing a correct diagnosis and instituting appropriate treatment.

Background: Substantial research links many of the defining characteristics of primary care to important outcomes; yet little is known about the relative importance of each characteristic, and several characteristics have not been examined. These analyses evaluate the relationship between seven defining elements of primary care (accessibility, continuity, comprehensiveness, integration, clinical interaction, interpersonal treatment, and trust) and three outcomes (adherence to physician's advice, patient satisfaction, and improved health status)., Methods: Data were derived from a cross-sectional observational study of adults employed by the Commonwealth of Massachusetts (N = 7204). All patients completed a validated questionnaire, the Primary Care Assessment Survey. Regression methods were used to examine the association between each primary care characteristic (11 summary scales measuring 7 elements of care) and each outcome., Results: Physicians' comprehensive ("whole person") knowledge of patients and patients' trust in their physician were the variables most strongly associated with adherence, and trust was the variable most strongly associated with patients' satisfaction with their physician. With other factors equal, adherence rates were 2.6 times higher among patients with whole-person knowledge scores in the 95th percentile compared with the 5th percentile (44.0% adherence vs 16.8% adherence, P < .001). The likelihood of complete satisfaction was 87.5% for those with 95th percentile trust scores compared with 0.4% for patients with 5th percentile trust scores (P < .001). The leading correlates of self-reported health improvements were integration of care, thoroughness of physical examinations, communication, comprehensive knowledge of patients, and trust (P < .001)., Conclusions: Patients' trust in their physician and physicians' knowledge of patients are leading correlates of three important outcomes of care. The results are noteworthy in the context of pervasive changes in our nation's health care system that are widely viewed as threatening to the quality of physician-patient relationships.

Objective: To examine how Asian-American patients' ratings of primary care performance differ from those of whites. Latinos, and African-Americans., Design: Retrospective analyses of data collected in a cross-sectional study using patient questionnaires., Setting: University hospital primary care group practice., Participants: In phase 1, successive patients who visited the study site for appointments were asked to complete the survey. In phase 2, successive patients were selected who had most recently visited each physician, going back as far as necessary to obtain 20 patients for each physician. In total, 502 patients were surveyed, 5% of whom were Asian-American., Main Results: After adjusting for potential confounders, Asian-Americans rated overall satisfaction and 10 of 11 scales assessing primary care significantly lower than whites did. Dimensions of primary care that were assessed include access, comprehensiveness of care, integration, continuity, clinical quality, interpersonal treatment, and trust. There were no differences for the scale of longitudinal continuity. On average, the rating scale scores of Asian-Americans were 12 points lower than those of whites (on 100-point scales)., Conclusions: We conclude that Asian-American patients rate physicians primary care performance lower than do whites, African-Americans, and Latinos. Future research needs to focus on Asian-Americans to determine the generalizability of these findings and the extent to which they reflect differences in survey response tendencies or actual quality differences.

The case history of a 19-year-old female with left ankle pain of 18 months' duration is presented. The reader is encouraged to make his or her own diagnosis after reviewing the history, laboratory values, and imaging. The final diagnosis with a full explanation and differential diagnosis will follow.

The case of a 27-year-old female, 5 years after a motor vehicle accident that resulted in spinal cord damage, is reviewed. She progressed well after her accident for 4 years, at which time she developed a neuropathic heel ulceration, aggravated by her calcaneal gait and pregnancy weight gain. The rarity of such a case involving neuropathic ulceration and calcaneal gait after partial deficit of cauda equina function prompted this article.

Objective: To compare physical and mental health outcomes of chronically ill adults, including elderly and poor subgroups, treated in health maintenance organization (HMO) and fee-for-service (FFS) systems., Study Design: A 4-year observational study of 2235 patients (18 to 97 years of age) with hypertension, non-insulin-dependent diabetes mellitus (NIDDM), recent acute myocardial infarction, congestive heart failure, and depressive disorder sampled from HMO and FFS systems in 1986 and followed up through 1990. Those aged 65 years and older covered under Medicare and low-income patients (200% of poverty) were analyzed separately., Setting and Participants: Offices of physicians practicing family medicine, internal medicine, endocrinology, cardiology, and psychiatry, in HMO and FFS systems of care. Types of practices included both prepaid group (72% of patients) and independent practice association (28%) types of HMOs, large multispecialty groups, and solo or small, single-specialty practices in Boston, Mass, Chicago, Ill, and Los Angeles, Calif., Outcome Measures: Differences between initial and 4-year follow-up scores of summary physical and mental health scales from the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) for all patients and practice settings., Results: On average, physical health declined and mental health remained stable during the 4-year follow-up period, with physical declines larger for the elderly than for the nonelderly (P<.001). In comparisons between HMO and FFS systems, physical and mental health outcomes did not differ for the average patient; however, they did differ for subgroups of the population differing in age and poverty status. For elderly patients (those aged 65 years and older) treated under Medicare, declines in physical health were more common in HMOs than in FFS plans (54% vs 28%; P<.001). In 1 site, mental health outcomes were better (P<.05) for elderly patients in HMOs relative to FFS but not in 2 other sites. For patients differing in poverty status, opposite patterns of physical health (P<.05) and for mental health (P<.001) outcomes were observed across systems; outcomes favored FFS over HMOs for the poverty group and favored HMOs over FFS for the nonpoverty group., Conclusions: During the study period, elderly and poor chronically ill patients had worse physical health outcomes in HMOs than in FFS systems; mental health outcomes varied by study site and patient characteristics. Current health care plans should carefully monitor the health outcomes of these vulnerable subgroups.

Over the past several years there has been a dramatic rise in the incidence of tuberculosis. Peripheral skeletal tuberculosis is, more often than not, misdiagnosed as osteoarthritis or pyogenic osteomyelitis. Tuberculosis is no longer a "zebra" among differential diagnoses. This article reviews the pathogenesis, along with practical tips for the diagnosis and treatment of osteoarticular tuberculosis.

This article discusses a number of different situations in which prophylaxis against infection may be considered by the podiatric physician. The authors cover some of these areas, including wound and laceration prophylaxis, surgical prophylaxis, and prophylaxis against the possibility of developing bacterial endocarditis following a podiatric procedure.

Study Objectives: To examine the feasibility of administering and the psychometric properties of a general health status questionnaire in adults with epilepsy, and to assess the health status of these patients., Design: Prospective, cross-sectional, observational study., Setting: Neurology clinic of a tertiary care medical center., Patients: One hundred forty-eight ambulatory adults with epilepsy., Interventions: Patients completed the SF-36, a general health status questionnaire. Respondent burden and data quality as well as psychometric characteristics were evaluated. Patients' SF-36 scale scores, adjusted for comorbidities, were compared with those of 641 people without chronic conditions with the same sociodemographic characteristics., Measurements and Main Results: Administering the SF-36 to adult outpatients with epilepsy is feasible and results are psychometrically sound. Compared with those who were not ill, patients had significantly (p < 0.001) lower (0 = worst, 100 = best) scores in six of the eight SF-36 domains: general health perceptions (57.7 vs 82.1), mental health (61.3 vs 79.6), vitality (53.5 vs 67.8), role limitations owing to physical (69.6 vs 95.0) and emotional problems (67.2 vs 88.4), and social functioning (75.2 vs 89.9)., Conclusions: Lower SF-36 scores may reflect patients' assessments of the balance among epilepsy, seizures, and antiepileptic drug therapy-related effects. Incorporating health status information into therapeutic decision making may help to attain the ultimate goal of improving patients' health.

Physical component summary (PCS) and mental component summary (MCS) measures make it possible to reduce the number of statistical comparisons and thereby the role of chance in testing hypotheses about health outcomes. To test their usefulness relative to a profile of eight scores, results were compared across 16 tests involving patients (N = 1,440) participating in the Medical Outcomes Study. Comparisons were made between groups known to differ at a point in time or to change over time in terms of age, diagnosis, severity of disease, comorbid conditions, acute symptoms, self-reported changes in health, and recovery from clinical depression. The relative validity (RV) of each measure was estimated by a comparison of statistical results with those for the best scales in the same tests. Differences in RV among scales from the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) were consistent with those in previous studies. One or both of the summary measures were significant for 14 of 15 differences detected in multivariate analyses of profiles and detected differences missed by the profile in one test. Relative validity coefficients ranged from .20 to .94 (median, .79) for PCS in tests involving physical criteria and from .93 to 1.45 (median, 1.02) for MCS in tests involving mental criteria. The MCS was superior to the best SF-36 scale in three of four tests involving mental health. Results suggest that the two summary measures may be useful in most studies and that their empiric validity, relative to the best SF-36 scale, will depend on the application. Surveys offering the option of analyzing both a profile and psychometrically based summary measures have an advantage over those that do not.

We studied 31 previously validated and newly developed generic and epilepsy-specific scales to evaluate their usefulness for assessing the impact of epilepsy and anti-epileptic drug (AED) therapy on health-related quality of life (HRQOL). Included were the MOS SF-36 Health Survey, additional measures of mental health, cognition, epilepsy-specific perception of control, behavioural problems, distress, worries and experiences, the Liverpool Epilepsy Impact and Seizure Severity scales, and a patient-completed symptom checklist. Questionnaires were completed twice by 136 patients on AED therapy in a multicentre study in the UK. Validity was assessed in relation to disease severity, defined as time since last seizure, and to patient-reported symptoms. Statistical analyses to estimate the contribution of HRQOL information of each scale relative to that of others were conducted. The 171-item questionnaire could be completed by out-patients with epilepsy with good data quality. With few exceptions, generic and epilepsy-specific measures satisfied psychometric tests of hypothesized item groupings and scale score reliability (internal consistency and test-retest reliability) and differentiated well between groups of patients differing in time since last seizure and in symptom impact, regardless of time since last seizure. However, scales differed widely in their validity in discriminating between groups of patients known to differ clinically. The SF-36 Role Physical scale best discriminated among groups differing in disease severity. The epilepsy-specific Mastery, Impact, Experience, Worry, Distress, and Agitation scales were among the 10 best measures in discriminating among groups differing in disease severity. Generic measures, especially measures of social and role functioning and mental health, were best at differentiating groups of patients differing in symptom impact. Recommendations are offered for concepts and specific scales most likely to be useful in future studies of the HRQOL burden of epilepsy and the HRQOL benefits of AED therapy.

Objective: To determine how patients in different kinds of practices--solo or single specialty (SOLO), multispecialty group (MSG), or health maintenance organizations (HMOs)--and with fee-for-service (FFS) or prepaid physician payment arrangements evaluate their medical care., Design: Survey of adult outpatients after office visits, with sample weighted to represent population of patients visiting physicians in each practice type., Setting: Offices of 367 internists, family practitioners, endocrinologists, cardiologists, and nurse practitioners, in HMOs (prepaid only), MSGs (prepaid and FFS), and SOLO practices (prepaid and FFS)., Patients: Adults (N = 17,671) at start of the Medical Outcomes Study., Outcome Measures: Overall rating of the visit (five choices from excellent to poor). A random half of the sample also rated the provider's technical skills, personal manner, and explanations of care as well as time spent during the visit, the appointment wait, the office wait, the convenience of the office location, and telephone access., Results: Fifty-five percent of patients rated their visit overall as excellent, 32% very good, 11% good, and 2% fair or poor. Patients of SOLO practitioners were more likely (64%) to rate their visit excellent than MSG (48%) or HMO (49%) patients (P < .001). Patients of SOLO practitioners rated all aspects of care better than HMO patients did, most markedly appointment waits (64% vs 40% excellent; P < .0001) and telephone access (64% vs 33% excellent; P < .0001). Within SOLO and MSG practices, FFS patients rated most specific aspects better than prepaid patients, but these differences were not statistically significant and were inconsistent across cities. Adjusting for patients' demographics, diagnoses and self-rated health did not change results. Physicians with visit ratings in the lowest 20% were nearly four times as likely to be left by patients within 6 months than physicians in the highest 20% (16.7% vs 4.6%; P < .001)., Conclusion: Of the five practice type and payment method combinations, SOLO FFS patients rated their visits best and HMO patients worst. Whether FFS or prepaid, care was rated better in small than in large practices. Our study shows that a brief visit rating form can be used to compare practice settings and health plans, and that patient ratings predict what proportion of patients, on average, will leave their physicians in the next several months.

HIV infection causes a wide spectrum of complications affecting all organ systems. These complications may be primary to the direct infection of a specific organ system by HIV or secondary to the immunodeficiency associated with HIV infection. These complications may be specific to certain stages of HIV infection. Selected common complications of HIV infection include pulmonary, neurologic, GI, dermatologic, oral, ocular, endocrine, and hematologic complications.

Because induction of proteolytic activity and stress-response proteins can significantly affect expression levels in recombinant Escherichia coli, the influence of low-level expression of a mutant beta-galactosidase was investigated. A single copy of the well-characterized CSH11 mutant of the lacZ gene was integrated into the chromosome. Induction of expression of the mutant beta-galactosidase caused a measurable increase in ATP-dependent intracellular proteolytic activity but resulted in no significant change in ATP-independent proteolytic activity. Growth at temperatures above 40 degrees C resulted in a significant decrease in the level of ATP-independent proteolytic activity compared to growth at 37 degrees C, and the ATP-dependent activity increased 2.5-fold from 30 to 42 degrees C. Synthesis of stress-response proteins was evident in two-dimensional gel electrophoresis analysis of proteins in the strain expressing the abnormal beta-galactosidase at 37 degrees C, but no such response was evident when mutant beta-galactosidase expression was induced at 30 degrees C. In separate experiments, stress proteins were overexpressed by inducing expression of the htpR gene on a plasmid. Resulting increases in stress-protein levels correlated with an increase in ATP-dependent proteolytic activity with no significant change in the intracellular ATP-independent proteolytic activity. These data suggest that even very low levels of abnormal protein can substantially influence protease levels and stress response in E. coli. These responses were reduced by induction at lower temperatures.

Structural properties of two similar beta-galactosidase fragments were investigated to determine how they influence the fragments' degradation rate in Escherichia coli. Both fragments resulting from a C-terminal nonsense mutation in lacZ, the CSH11 polypeptide and its 90 kDa degradative intermediate, exist predominantly as monomer subunits instead of in the tetrameric form characteristic of the native enzyme. However, both fragments appear to produce trace amounts of dimers and tetramers. The tetramer and higher molecular weight aggregates formed by the wild-type subunit confer greater protection for the enzyme's N-terminal auto-alpha polypeptide than does the monomer state of the beta-galactosidase fragments. The thermally induced aggregation of both beta-galactosidase fragments correlates with their sensitivity to alpha-chymotrypsin. The relatively low thermal stability of the 90 kDa degradative intermediate appears to be the cause of the significant increase in its proteolytic susceptibility at moderately high temperatures.

Intracellular protein degradation was investigated using an unstable fragment of Escherichia coli beta-galactosidase, the CSH11 mutant, as a model protein. This abnormal protein was expressed from a single copy gene in the chromosome and is converted to a detectable degradable intermediate. The in vivo degradation rates of both beta-galactosidase fragments were measured using pulse-chase radioactive labeling techniques, and their intracellular concentrations were determined using alpha-complementation assays. In the physiological range of 30 to 37 degrees C, the apparent degradation rate constant for the CSH11 fragment follows Arrhenius behavior; while the intermediate's apparent degradation rate constant is nearly unchanged. However, above 37 degrees C the degradation rates of both fragments increase significantly. Analysis of the labeled intermediate's rate of change above 40 degrees C reveals that the CSH11 fragment is being degraded by a second pathway which does not produce the intermediate. When the induction level of the abnormal beta-galactosidase was varied the degradation rates of both fragments behaved similarly, but they unexpectedly decreased with increasing IPTG concentration. The two parallel degradation pathways for CSH11 apparently operated at only the lower IPTG levels. The measured degradation rates did not correlate directly with the intracellular concentration of abnormal proteins.

In some cases, nail changes may not only be the presenting sign of systemic disease, but a sensitive indicator of treatment efficacy as well. Awareness of nail dystrophies and their association with underlying pathology can aid the practitioner in the diagnosis and management of the podiatric patient.