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We introduce a conceptual model of the urban forest patch as a complex social-ecological system, incorporating cross-scale interactions. We developed this model through an interdisciplinary process engaging social and ecological scientists and urban land management decision makers, with a focus on temperate forest social-ecological systems. In this paper, we place the production and management of urban forest patches in historical perspective, present a conceptual model of urban forest patches within a broader regional context, and identify a series of research questions to highlight future directions for research on urban forest patches. This conceptual model identifies how spatial and temporal social-ecological drivers interact with patch-level conditions at multiple scales. Our integrative approach can provide insights into the role of social-ecological drivers in shaping forest health, biodiversity, and benefits forest patches provide to people in urban and urbanizing regions, with direct implications for decision-making to improve management outcomes.

Objective: To examine the role of executive function in coping and behavioral outcomes in childhood acute lymphocytic leukemia (ALL) survivors.Methods: We examined associations among several domains of executive function (working memory, behavioral inhibition, cognitive flexibility, and self-monitoring), coping, and emotional/behavioral problems in 30 children and adolescents ages 10- to 20-years old who completed treatment for ALL and 30 healthy controls matched on age and sex.Results: We found partial support for our hypothesis that performance on executive function measures is associated with strategies used to cope with stress, and emotional and behavioral problems in ALL survivors.Conclusions: Findings suggest that executive function impairment may be associated with difficulties in coping and emotion regulation in a subgroup of children treated for ALL. Directions for future research on executive function deficits and coping skills in survivors of pediatric ALL are suggested. [ABSTRACT FROM AUTHOR]

We argue that walking as a method provides an integrative approach to advance epistemic justice in sustainability research. The theory and practice of walking as a method has grown quickly within the social sciences and arts but remains underrepresented in sustainability research, where walking is typically an object of study (e.g., urban walkability). We argue that walking should be valued as an important mode of knowledge production that simultaneously widens sustainability knowledge, integrates diverse knowledge systems, and supports transdisciplinary sustainability solutions. In this perspective article, we consider the following questions: (1) Why is walking important to sustainability knowledge? (2) How can walk-based methods advance epistemic justice in sustainability knowledge? (3) What outcomes might we expect from cultivating walking as a method for sustainability knowledge? We reflect on how walking as a method centers equity and the contributions of walk-based sustainability knowledge for research and policy., (© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

Endoscopic evidence of disease activity is a critical predictor of clinical relapse in patients with Crohn's disease (CD), and histologic disease activity is evolving as a similarly important end point for patient management. However, classical morphologic features of CD may overlap with postoperative inflammatory changes, confounding the evaluation of anastomotic biopsies. There is a clear unmet need for better characterization of diagnostic and clinically significant histologic features of CD in these surgically altered sites. We evaluated ileocolonic and colocolonic/rectal anastomotic biopsies performed at 3 academic institutions in patients with and without CD. The biopsies were blindly assessed for CD histologic features and correlated to clinical and endoscopic characteristics. In CD patients, the presence of each feature was correlated with the subsequent clinical exacerbation or relapse. We obtained anastomotic biopsies from 208 patients, of which 109 were operated on for CD and 99 for another indication (neoplasia [80%], diverticular disease (11%), and other [9%]). Mean time since surgery was 10 years (0-59; 14 years for CD [1-59], 6 years for non-CD [0-33]). Endoscopic inflammation was noted in 52% of cases (68% for CD and 35% for non-CD). Microscopic inflammation was present in 74% of cases (82% for CD and 67% for non-CD). Only discontinuous lymphoplasmacytosis (P < .001) and pyloric gland metaplasia (P = .04) occurred significantly more often in CD patients. However, none of the histologic features predicted clinical disease progression. In subset analysis, the presence of histologic features of CD in nonanastomotic biopsies obtained concurrently in CD patients was significantly associated with relapse (P = .03). Due to extensive morphologic overlap between CD and postoperative changes and the lack of specific histologic features of relapse, biopsies from anastomotic sites are of no value in predicting clinical CD progression. Instead, CD activity in biopsies obtained away from anastomotic sites should be used for guiding endoscopic sampling and clinical management., (Copyright © 2023 United States & Canadian Academy of Pathology. Published by Elsevier Inc. All rights reserved.)

Tripartite motif (TRIM) proteins are involved in development, innate immunity, and viral restriction. TRIM gene repertoires vary between species, likely due to diversification caused by selective pressures from pathogens; however, this has not been explored in birds. We mined a de novo assembled transcriptome for the TRIM gene repertoire of the domestic mallard duck ( Anas platyrhynchos ), a reservoir host of influenza A viruses. We found 57 TRIM genes in the duck, which represent all 12 subfamilies based on their C-terminal domains. Members of the C-IV subfamily with C-terminal PRY-SPRY domains are known to augment immune responses in mammals. We compared C-IV TRIM proteins between reptiles, birds, and mammals and show that many C-IV subfamily members have arisen independently in these lineages. A comparison of the MHC-linked C-IV TRIM genes reveals expansions in birds and reptiles. The TRIM25 locus with related innate receptor modifiers is adjacent to the MHC in reptile and marsupial genomes, suggesting the ancestral organization. Within the avian lineage, both the MHC and TRIM25 loci have undergone significant TRIM gene reorganizations and divergence, both hallmarks of pathogen-driven selection. To assess the expression of TRIM genes, we aligned RNA-seq reads from duck tissues. C-IV TRIMs had high relative expression in immune relevant sites such as the lung, spleen, kidney, and intestine, and low expression in immune privileged sites such as in the brain or gonads. Gene loss and gain in the evolution of the TRIM repertoire in birds suggests candidate immune genes and potential targets of viral subversion., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Campbell, Peery and Magor.)

Ducks are the natural host and reservoir of influenza A virus (IAV), and as such are permissive to viral replication while being unharmed by most strains. It is not known which mechanisms of viral control are globally regulated during infection, and which are specific to tissues during infection. Here we compare transcript expression from tissues from Pekin ducks infected with a recombinant H5N1 strain A/Vietnam 1203/04 (VN1203) or an H5N2 strain A/British Columbia 500/05 using RNA-sequencing analysis and aligning reads to the NCBI assembly ZJU1.0 of the domestic duck ( Anas platyrhynchos ) genome. Highly pathogenic VN1203 replicated in lungs and showed systemic dissemination, while BC500, like most low pathogenic strains, replicated in the intestines. VN1203 infection induced robust differential expression of genes all three days post infection, while BC500 induced the greatest number of differentially expressed genes on day 2 post infection. While there were many genes globally upregulated in response to either VN1203 or BC500, tissue specific gene expression differences were observed. Lungs of ducks infected with VN1203 and intestines of birds infected with BC500, tissues important in influenza replication, showed highest upregulation of pattern recognition receptors and interferon stimulated genes early in the response. These tissues also appear to have specific downregulation of inflammatory components, with downregulation of distinct sets of proinflammatory cytokines in lung, and downregulation of key components of leukocyte recruitment and complement pathways in intestine. Our results suggest that global and tissue specific regulation patterns help the duck control viral replication as well as limit some inflammatory responses in tissues involved in replication to avoid damage., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Campbell, Fleming-Canepa, Webster and Magor.)

Mallard ducks are a natural host and reservoir of avian Influenza A viruses. While most influenza strains can replicate in mallards, the virus typically does not cause substantial disease in this host. Mallards are often resistant to disease caused by highly pathogenic avian influenza viruses, while the same strains can cause severe infection in humans, chickens, and even other species of ducks, resulting in systemic spread of the virus and even death. The differences in influenza detection and antiviral effectors responsible for limiting damage in the mallards are largely unknown. Domestic mallards have an early and robust innate response to infection that seems to limit replication and clear highly pathogenic strains. The regulation and timing of the response to influenza also seems to circumvent damage done by a prolonged or dysregulated immune response. Rapid initiation of innate immune responses depends on viral recognition by pattern recognition receptors (PRRs) expressed in tissues where the virus replicates. RIG-like receptors (RLRs), Toll-like receptors (TLRs), and Nod-like receptors (NLRs) are all important influenza sensors in mammals during infection. Ducks utilize many of the same PRRs to detect influenza, namely RIG-I, TLR7, and TLR3 and their downstream adaptors. Ducks also express many of the same signal transduction proteins including TBK1, TRIF, and TRAF3. Some antiviral effectors expressed downstream of these signaling pathways inhibit influenza replication in ducks. In this review, we summarize the recent advances in our understanding of influenza recognition and response through duck PRRs and their adaptors. We compare basal tissue expression and regulation of these signaling components in birds, to better understand what contributes to influenza resistance in the duck., (Copyright © 2020 Campbell and Magor.)

Background: Formal psychosocial support programs after weight-loss surgery are limited in scope and availability., Objective: This randomized pilot study evaluated the feasibility of a postoperative behavioral intervention program., Materials and Methods: Postoperative weight-loss surgery patients (N = 50) were recruited from February 2017-July 2017 and randomized to a four-month behavioral program or usual care wait-list. Outcomes evaluated in addition to feasibility included health-related quality of life (Short Form -36), psychosocial functioning and adherence. Secondary outcomes included within-group changes for each outcome., Results: Out of eight possible sessions, intervention participants attended a mean of 4.2 sessions. Intervention group participants experienced greater improvements in the social functioning domain of health-related quality of life compared to usual care. Self-reported dietary adherence in the intervention group remained stable, while usual care group dietary adherence declined. Within the intervention group, participants also reported gains in the physical function, pain and general health aspects of quality life from baseline to post-treatment. No differences in weight, mood or other eating behaviors (e.g., loss of control, emotional eating) were evident between groups., Conclusion: Though participation in a postoperative behavioral intervention varied, the program helped participants to maintain aspects of quality of life and self-reported adherence to dietary recommendations., Trial Registration: ClinicalTrials.gov NCT03092479., Competing Interests: The authors have declared that no competing interests exist.

Background: History of abuse may impact weight loss (WL) following bariatric surgery. Some investigations have indicated slower WL rates among patients reporting abuse; however, among studies with multiple assessments, significant differences in WL are not evidenced at later measurement. Few investigations have extended follow-up beyond 18 months, limiting understanding of the impact of abuse on weight trajectory over time. Furthermore, existing research has insufficiently accounted for forms of interpersonal trauma beyond sexual abuse (i.e., emotional, physical) that may impact WL and other health outcomes., Objectives: To determine whether post-surgical percent total WL (%TWL) and specific clinical outcomes are differentially impacted by history of interpersonal abuse., Setting: Large, comprehensive medical center., Methods: Retrospective data was collected from patients who underwent bariatric surgery at a single center (N = 433). Based on pre-surgical interview, patients were grouped according to reported history of interpersonal abuse (Y/N). Nonlinear repeated measures regression examined impact of abuse history on %TWL, and clinical selequae., Results: Differences in %TWL at 6, 12, 18, 24, and 36 months post-surgically did not differ significantly. Further, %TWL did not differ across time, according to group. A significantly greater number of those with history of interpersonal abuse had a clinical diagnosis of depression as compared with those not reporting interpersonal abuse (38% vs. 22% respectively), p < .001., Conclusions: Interpersonal abuse history does not negatively impact %TWL post-surgically but is associated with diagnosis of depression, indicating depressive symptoms may be a viable clinical intervention target for surgery patients with interpersonal trauma history.

This work presents experimental and analytical comparison of terahertz transmission and reflection imaging modes for assessing breast carcinoma in excised paraffin-embedded human breast tissue. Modeling for both transmission and reflection imaging is developed. The refractive index and absorption coefficient of the tissue samples are obtained. The reflection measurements taken at the system's fixed oblique angle of 30° are shown to be a hybridization of TE and TM modes. The models are validated with transmission spectroscopy at fixed points on fresh bovine muscle and fat tissues. Images based on the calculated absorption coefficient and index of refraction of bovine tissue are successfully compared with the terahertz magnitude and phase measured in the reflection mode. The validated techniques are extended to 20 and 30 μm slices of fixed human lobular carcinoma and infiltrating ductal carcinoma mounted on polystyrene microscope slides in order to investigate the terahertz differentiation of the carcinoma with non-cancerous tissue. Both transmission and reflection imaging show clear differentiation in carcinoma versus healthy tissue. However, when using the reflection mode, in the calculation of the thin tissue properties, the absorption is shown to be sensitive to small phase variations that arise due to deviations in slide and tissue thickness and non-ideal tissue adhesion. On the other hand, the results show that the transmission mode is much less sensitive to these phase variations. The results also demonstrate that reflection imaging provides higher resolution and more clear margins between cancerous and fibroglandular regions, cancerous and fatty regions, and fibroglandular and fatty tissue regions. In addition, more features consistent with high power pathology images are exhibited in the reflection mode images.

Cities are increasingly engaging in sustainability efforts and investment in green infrastructure, including large-scale urban tree planting campaigns. In this context, researchers and practitioners are working jointly to develop applicable knowledge for planning and managing the urban forest. This paper presents three case studies of knowledge co-production in the field of urban forestry in the United States. These cases were selected to span a range of geographic scales and topical scopes; all three are examples of urban researcher-practitioner networks in which the authors are situated to comment on reflexively. The three cases resemble institutional structures described in the knowledge co-production literature, including participatory research, a hybrid organization of scientists and managers, and a community of practice. We find that trust, embeddedness, new approaches by both practitioners and researchers, and blending of roles all serve to recognize multiple forms of capability, expertise, and ways of knowing. We discuss the impacts of knowledge co-production and the ways in which hybrid institutional forms can enable its occurrence.

Wild waterfowl, including mallard ducks, are the natural reservoir of avian influenza A virus and they are resistant to strains that would cause fatal infection in chickens. Here we investigate potential involvement of TRIM proteins in the differential response of ducks and chickens to influenza. We examine a cluster of TRIM genes located on a single scaffold in the duck genome, which is a conserved synteny group with a TRIM cluster located in the extended MHC region in chickens and turkeys. We note a TRIM27-like gene is present in ducks, and absent in chickens and turkeys. Orthologous genes are predicted in many birds and reptiles, suggesting the gene has been lost in chickens and turkeys. Using quantitative real-time PCR (qPCR) we show that TRIM27-L, and the related TRIM27.1, are upregulated 5- and 9-fold at 1 day post-infection with highly pathogenic A/Vietnam/1203/2004. To assess whether TRIM27.1 or TRIM27-L are involved in modulation of antiviral gene expression, we overexpressed them in DF1 chicken cells, and neither show any direct effect on innate immune gene expression. However, when co-transfected with duck RIG-I-N (d2CARD) to constitutively activate the MAVS pathway, TRIM27.1 weakly decreases, while TRIM27-L strongly activates innate immune signaling leading to increased transcription of antiviral genes MX1 and IFN-β. Furthermore, when both are co-expressed, the activation of the MAVS signaling pathway by TRIM27-L over-rides the inhibition by TRIM27.1. Thus, ducks have an activating TRIM27-L to augment MAVS signaling following RIG-I detection, while chickens lack both TRIM27-L and RIG-I itself., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Background: The aim of our study was to develop a prognostic index score for patients undergoing surgical resection for esophageal cancer that accurately determines survival with specific clinicopathological characteristics., Methods: Clinical, histological, and demographical variables of 475 patients were entered in an univariate and multivariate regression model, followed by individual calculation of the Prognostic Indicator Score and model validation via simulation., Results: Significant variables included in the scoring system were number of positive lymph nodes, pT, pL, R, obesity, and American Society of Anesthesiologist classification. Survival probability and its associated hazard function was significantly different between the scores, with an increase of hazard ratio ranging from 2.56 (score 2) to 20 (score 6 or higher). Comparing histological cancer entities revealed statistical significance only between stage IIA versus IIB in squamous cell and stage IIIA versus IIIB in adenocarcinoma., Conclusions: According to our methodology, an individualized follow-up by each possible score might allow interdisciplinary selection of patients for treatments based on expected survival. This may represent a breakthrough in patient selection for currently available treatments and clinical studies., (Georg Thieme Verlag KG Stuttgart · New York.)

Driving is a dangerous activity for adolescents, perhaps being even more precarious for adolescents with type 1 diabetes due to the possibility of extreme blood glucose (BG). There is no available data on adolescent driving safety concerns and type 1 diabetes. To begin addressing this issue, we surveyed parents regarding their observations and concerns. Seventy-two parents (87.5% mothers) of adolescent drivers aged 16-19 with type 1 diabetes provided analyzable data. Females comprised 36% of their adolescents, with 74% using pump therapy. In the past year, 13 and 84% of parents reported that their adolescent had experienced severe or moderate disruptive hypoglycemia, respectively. Over half (56%) of the parents reported moderate to extreme worry about how diabetes impacted their adolescent's driving, while only 21% of parents thought their adolescents had similar concerns (p = 0.037). Almost one third (31%) of parents thought their adolescent need not treat low BG until it fell below 70 mg/dL, 13% thought their adolescent could safely drive with BG below 65 mg/dL. And, 31 and 14% of parents, respectively, reported their adolescent had been in a collision or stopped by the police in the past year, which they attributed to both hypo- and hyperglycemia. Adolescents reportedly took steps to prevent hypo- and hyperglycemia while driving, but more aggressively avoided hypoglycemia (p < 0.001). While this data is limited, lacking a non-diabetic control group and randomized sample, it does suggest that driving and adolescent type 1 diabetes deserve further attention and investigation., (© 2012 John Wiley & Sons A/S.)

This study examined whether a 20-min session of prefrontal transcranial direct current stimulation (tDCS) (anode over the right prefrontal cortex and cathode over the left prefrontal cortex) would reduce food cravings and increase the self-reported ability to resist foods in 19 healthy individuals who reported frequent food cravings. Participants viewed computerized images of food and used computerized visual analogue scales to rate food cravings and inability to resist foods before, during, and after receiving either real or sham tDCS. This study employed a randomized within-subject crossover design; participants received both real and sham tDCS and were blind to the condition. Food cravings ratings were reduced in both conditions, however, the percent change in cravings ratings from pre- to post-stimulation was significantly greater for real stimulation than for sham. The percent change in inability to resist food from pre- to post-stimulation also showed a greater decrease in the real condition than for sham. Post hoc analyses suggest that active prefrontal tDCS acutely and significantly decreased food cravings ratings for sweet foods and carbohydrates more so than sham tDCS. No significant differences were seen in the amount of food ingested between real and sham tDCS. These findings in healthy subjects indicate that tDCS is able to temporarily reduce food cravings and improve the self-reported ability to resist foods., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

OBJECTIVE: A subset of drivers with type 1 diabetes mellitus (T1DM) may be at significant risk of hypoglycemia-related driving collisions and moving vehicle violations due to acute and chronic neurocognitive impairment. The present study compared drivers with T1DM with and without a recent history of multiple driving mishaps on a neurocognitive battery during euglycemia, progressive mild hypoglycemia, and recovery from hypoglycemia, to determine whether neurocognitive measures differentiate the two risk groups. We hypothesized that drivers with a history of multiple recent hypoglycemia-related driving mishaps would demonstrate greater psychomotor slowing, both during hypoglycemia and euglycemia. STUDY DESIGN: Partcipants were 42 adults with T1DM and were assigned to one of two groups: those reporting no driving mishaps in the last year (-History) and those reporting two or more (+History).Neurocognitive testing was conducted before and repeated during a hyper-insulinemic clamping procedure. RESULTS: Not surprisingly, all drivers demonstrated a decrease in functioning across all neurocognitive tasks during hypoglycemia. However, in contrast to the common belief that neurocognitive functions return slowly and gradually following hypoglycemia, baseline neurocognitive functioning immediately recovered upon return of BG to euglycemia for all subjects. Between-group analyses revealed that subjects with a recent history of driving mishaps consistently demonstrated poorer performance on tasks measuring working memory. CONCLUSION: Working memory is a potential neurocognitive indicator that may help differentiate adults with T1DM with and without a history of driving mishaps, predict future risk for driving mishaps, and provide targeted intervention programs to address this critical public health issue.

Background: Research on the physical and psychological late effects of treatment of childhood cancer has led to the identification of significant long-term neurocognitive deficits experienced by some survivors, particularly in the areas of memory and executive functioning. Despite indications of deficits based on cognitive assessment, the identification of specific mechanisms of neurocognitive deficits using neuroimaging techniques has yet to be adequately considered., Procedure: This study used functional neuroimaging techniques to examine working memory and executive functioning deficits of survivors of childhood acute lymphocytic leukemia (ALL), as compared to age- and gender-matched healthy controls., Results: There was a trend for ALL survivors to perform more poorly on a working memory task in terms of overall accuracy. Additionally, survivors displayed significantly greater activation in areas underlying working memory (dorsolateral and ventrolateral prefrontal cortex) and error monitoring (dorsal and ventral anterior cingulate cortex)., Conclusions: These results support the theory of compensatory activation in necessary brain regions in order to complete tasks in pediatric ALL survivors, similar to that observed in multiple sclerosis patients. Concurrent examination of testing and brain imaging enables the connection of behavioral observations with underlying neurological characteristics of deficits in survivors and may help provide insight into mechanisms through which deficits appear.

Background: The azoxymethane (AOM) model recapitulates many features of human colon cancer, lacking an inflammatory component. Dextran sulfate sodium (DSS) induces colitis and promotes AOM-induced colon cancer in mice. Vitamin D analogues are anti-inflammatory and chemopreventive in models of colon cancer. Our aim was to evaluate the anti-inflammatory and chemopreventive efficacy of the vitamin D analogue Ro26-2198 in the AOM/DSS model and in vitro in HCA-7 colon cancer cells., Materials and Methods: A/J mice received Ro26-2198 (0.01 microg/kg body wt/day x 28 days) or vehicle by mini-osmotic pump. Animals were treated with a single dose of AOM (5 mg/kg body wt) or vehicle 1 week after pump insertion. Mice received 3% DSS or water x 7 days beginning week 3. Animals were sacrificed after 8 weeks and colon segments were fixed in formalin or flash-frozen. Hematoxylin and eosin colonic sections were examined for dysplasia and colonic lysates were assessed for c-Myc, cyclooxygenase 2, and phospho-(active) extracellular signal regulated kinase (ERK) by Western blotting. For in vitro studies, HCA-7 cells were treated with Ro26-2198 followed by interleukin-1beta (IL-1beta). Proliferation was measured by WST-1 assay., Results: Ro26-2198 delayed the onset of clinical colitis. Several dysplastic foci were present in the AOM/DSS group; none were found in the Ro26-2198 group. Compared with control, AOM/DSS significantly increased c-Myc (15-fold), cyclooxygenase 2 (COX-2) (2.5-fold), and pERK (10-fold), and Ro26-2198 abolished these increases. In vitro, Ro26-2198 inhibited IL-1beta-induced ERK activation and COX-2 induction and decreased HCA-7 cell proliferation., Conclusions: Ro26-2198 inhibited proliferative (ERK, c-Myc) and pro-inflammatory (COX-2) signals and progression to dysplasia, suggesting chemopreventive efficacy in this model of colitis-associated carcinogenesis.

Background: Impaired neurocognitive functioning is one increasingly recognized long-term consequence of childhood ALL treatment. However, research findings have been inconsistent regarding the domains affected and the degree to which they are compromised., Procedure: A comprehensive meta-analytic review of the long-term neurocognitive effects of childhood ALL was conducted. Studies were included if they were published in English, reported original quantitative data on the post-treatment neurocognitive functioning of childhood ALL patients in first remission and control groups, and used neurocognitive measures with adequate psychometric properties and published normative data., Results: Data from 28 empirical studies yielding 13 effect sizes across nine domains were extracted and analyzed. All effects were negative (g = -0.34 to -0.71), demonstrating that ALL survivors consistently experienced significant deficits in intellectual functioning, academic achievement, and specific neurocognitive abilities compared to control groups. The role of potential moderators, including treatment with cranial irradiation, age at time of diagnosis, and time since treatment ended, was examined. However, no effects emerged as clearly and consistently moderated by these variables., Conclusions: The results from this meta-analysis suggest that declines in both global and specific areas of areas of neurocognitive functioning occur as a result of contemporary ALL treatment. Such deficits have significant implications for survivors' academic achievement and overall quality of life. Neurocognitive assessment plays a critical role in determining what remedial or specialized instruction is needed in childhood ALL survivors and should be included as a standard part of long-term follow-up care.

The role of enteric bacteria in the pathogenesis of acute appendicitis is a controversial subject. Campylobacter jejuni has been previously demonstrated in a minority of cases of acute appendicitis using microbiological or immunohistochemical methods, notably in cases where inflammation was limited to the mucosa/submucosa. Our goal was to evaluate cases of acute appendicitis for C. jejuni DNA using molecular methods, and to compare our findings to the histologic features. In total, 50 archival cases of acute appendicitis were selected, and PCR was performed using primers targeting a 286-bp fragment of the mapA gene specific to C. jejuni. Twenty histologically unremarkable appendectomy specimens served as negative controls. Cases were reviewed with attention to particular histological features including mucosal ulceration, cryptitis, depth of inflammatory infiltrate, and the presence of mural necrosis. Of acute appendicitis cases, 22% (11/50) were positive for C. jejuni DNA by PCR analysis. Control cases were negative for C. jejuni DNA. All patients presented with signs and symptoms typical of acute appendicitis. Of the C. jejuni positive cases, only 27% contained acute inflammation limited to the mucosa/submucosa, whereas the remainder had mural or transmural inflammation; therefore, the histological features of C. jejuni-positive acute appendicitis cases were indistinguishable from C. jejuni-negative cases. In summary, C. jejuni DNA was detected in a significant percentage (22%) of acute appendicitis cases, a much higher percentage than previous studies using other methodologies. As C. jejuni is an enteric pathogen that does not exist as a commensal or nonpathogenic organism, the presence of C. jejuni DNA implies current or recent infection. Further study is needed to determine whether the presence of C. jejuni DNA in acute appendicitis indicates appendiceal involvement by C. jejuni enteritis, or if there is a true causative role for C. jejuni in acute appendicitis., (Copyright 2006 S. Karger AG, Basel.)

In non-neoplastic tissues, the expression of protein gene product 9.5 (PGP 9.5), a member of the ubiquitin hydrolase family of proteins, is confined to neural and neuroendocrine cells. Although it has been claimed that PGP 9.5 is a specific marker of neural and/or nerve sheath differentiation in human tumors, careful review of the literature suggests that relatively few nonneural or nerve sheath tumors have been studied. Prompted by our recent observation of a PGP 9.5-positive malignant fibrous histiocytoma, we undertook a study of PGP 9.5 expression in a large group of well-characterized mesenchymal neoplasms. Sections from 95 mesenchymal tumors were retrieved from our archives and immunostained for PGP 9.5 using standard avidin-biotin complex technique and heat-induced epitope retrieval. Scoring was as follows: negative, 1+ (<10-25% of cells), 2+ (25-50% of cells), and 3+ (>50% of cells). Normal nerves and fibrous tissue were internal positive and negative controls, respectively. Positive immunostaining was seen in 80/95 (84%) of cases. Positive results by tumor subtype were as follows: (1) nerve sheath tumors: malignant peripheral nerve sheath tumor (7/10), neurofibromas (10/10), and perineuriomas (3/3); (2) (Myo) fibroblastic tumors: malignant fibrous histiocytoma (18/20), low-grade fibromyxoid sarcomas (8/9), fibromatoses (7/7), and desmoplastic fibroblastomas (2/2); (3) vascular tumors: angiosarcomas (4/4), hemangioendotheliomas (3/5), and hemangiomas (3/4); and (4) other non-nerve sheath tumors: pleomorphic liposarcoma (4/4), dermatofibrosarcoma protuberans (2/5), rhabdomyosarcomas (2/2), synovial sarcomas (8/8), melanomas (1/2). All positive cases were 2-3+ except 6 malignant peripheral nerve sheath tumor, 1 neurofibroma, 3 malignant fibrous histiocytoma, 2 low-grade fibromyxoid sarcoma, and 1 dermatofibrosarcoma protuberans. Positive staining was seen in normal smooth muscle and germinal centers in addition to nerves. We conclude that in this, the largest study to date of PGP 9.5 expression in mesenchymal neoplasms, we have found strong (2-3+) expression in the vast majority of nonneural or nerve sheath neoplasms studied. Although PGP 9.5 is a sensitive neural/nerve sheath marker, it is essentially totally nonspecific for diagnostic purposes. It is possible that our findings reflect cross-reactivity of the 13C4 clone with epitopes present on other ubiquitin hydrolases. Alternatively, PGP 9.5 expression may be aberrantly up-regulated in a variety of mesenchymal neoplasms.

Objective: To evaluate miglitol, a new oral alpha-glucosidase inhibitor, and discuss its pharmacology, therapeutics, pharmacokinetics, dosing guidelines, adverse effects, drug interactions, and clinical efficacy., Data Sources: A MEDLINE English-language only database search using the keywords miglitol, glyset, and Bay m 1099 (1985 to December 1999), was completed to identify relevant articles including reviews, recent studies, and abstracts; American Diabetes Association 1999 Annual Meeting abstracts; Pharmacia & Upjohn data on file and product information., Study Selection: The clinical trials that were selected to be reviewed in detail were randomized, double-blind studies with at least 100 patients in the intention-to-treat group., Data Extraction: All articles and abstracts were reviewed along with the product labeling from Pharmacia & Upjohn., Data Synthesis: Miglitol is an alpha-glucosidase inhibitor that exerts its effect through the delayed absorption of complex carbohydrates in the small intestine, resulting in a decrease in postprandial glucose concentrations that are directly correlated with the dietary carbohydrate content. Both small, short-term trials and large, clinical trials show a decrease in postprandial glucose concentrations and a modest decrease in glycosylated hemoglobin of approximately 0.5-1.0% as a result of miglitol's action. The adverse effects of miglitol are mild and transitory and include flatulence, diarrhea, and abdominal pain. The incidence of gastrointestinal problems may be reduced with a small initial dose, which is slowly titrated as tolerated., Conclusions: Miglitol is an effective and safe treatment option in patients with type 2 diabetes mellitus who are inadequately controlled with diet or oral sulfonylurea therapy. Miglitol is a good choice of therapy in Hispanic, African-American, and elderly patients, or any patients in whom hypoglycemia, weight gain, or lactic acidosis are risks. No published studies comparing miglitol with acarbose have been published, but there appears to be no major clinical or financial advantages to using one agent over the other.

Objective: To introduce troglitazone (CS-045, Rezulin), a new oral antidiabetic agent and discuss its pharmacology, therapeutics, pharmacokinetics, dosing guidelines, adverse effects, drug interactions, and clinical efficacy., Data Sources: A MEDLINE database search was completed to identify relevant articles including reviews, recent studies and abstracts, and data from Parke-Davis., Study Selection: Due to the small number of published human studies available, some data are derived from animal studies and abstracts of human studies. Studies and abstracts chosen summarize the clinical action of troglitazone in healthy volunteers, in subjects with impaired glucose tolerance, and in patients with diabetes mellitus. Three of the six published human studies used subjects in a placebo-controlled, multicenter, randomized environment (type 2 diabetic patients or obese subjects with insulin resistance)., Data Extraction: All clinical trials available, including unpublished reports, were reviewed., Data Synthesis: Troglitazone is the first member of a new class of medications, the thiazolidinediones, to be approved for clinical use. Troglitazone increases insulin sensitivity in skeletal muscle and in hepatic and adipose tissue. It has been shown to decrease hepatic glucose output while having no effect on stimulating insulin secretion from the pancreatic beta-cells. Its metabolic effects decrease fasting and postprandial hyperglycemia, insulin concentrations, and triglyceride concentrations, while increasing high-density lipoprotein concentrations. There is some evidence, based on short-term trials, that troglitazone causes only minimal decreases in glycosylated hemoglobin A1C (HbA1C) concentrations. Data suggest that troglitazone decreases impaired glucose tolerance in nondiabetic obese subjects and leads to a reduction in both systolic and diastolic blood pressure in hypertensive type 2 diabetes mellitus patients. Troglitazone has a mild adverse effect profile, with rare instances of abnormal liver function tests., Conclusions: Troglitazone appears to be a safe, effective, and useful new agent in the treatment of insulin-requiring type 2 diabetes mellitus patients, although its HbA1C-lowering effects have been minimal in short-term trials, and its insulin dosage-reduction activity remains unclear. The Food and Drug Administration has also approved its use as monotherapy and in combination with sulfonylureas for patients with type 2 diabetes. It may have use in the treatment of patients with impaired glucose tolerance, but more clinical experience is needed before definitive conclusions can be made. The role of troglitazone therapy in diabetes mellitus and impaired glucose intolerance will continue to evolve as the results of studies and our clinical experience with this agent become available.

Diabetes mellitus is a chronic disease that affects many aspects of the lives of diagnosed patients and their families, the health care industry, and society. The majority of the economic literature on diabetes addresses the cost of treating diabetes but not the outcomes of clinical interventions. The primary cost of treating diabetes is related to short-term care to achieve euglycemia and long-term care associated with complication of the disease. The short-term costs of achieving euglycemia can be overshadowed by the decreased risk of long-term complications. The difficulty of providing care for a chronic disease such as diabetes arises from the high short-term costs of clinical interventions, the positive benefits of which may not be realized for many years. The results of the Diabetes Control and Complications Trial show a correlation between the intensive treatment of diabetes and a decreased risk of the development of long-term complications. Whether intensive treatment is practical, effective, and cost-effective in a real-world setting is a topic for further study. In the meantime, health care providers with a good knowledge of the clinical and economic elements of available therapeutic options can develop individualized care regimens for their patients with diabetes that are high quality and cost-effective.

Objective: To introduce a rapid-acting human insulin analog, insulin lispro; to review its pharmacology, therapeutics, pharmacokinetics, dosing guidelines, adverse effects, and drug interactions; and to summarize the clinical trials of its efficacy and safety alone and in comparison with regular human insulin in the treatment of diabetes mellitus., Data Sources: A MEDLINE database search was completed to identify all relevant articles, including reviews; Eli Lilly and Co.; published articles and abstracts; and review chapters from medical textbooks., Study Selection: Due to the relatively few citations listed in MEDLINE (12 as of December 1995), most of the studies reported were found from abstracts summarizing the clinical action, adverse effects, or pharmacokinetics of insulin lispro in healthy volunteers or patients with diabetes mellitus. A few of the studies used patients with diabetes mellitus in multicenter, randomized, crossover trials of insulin lispro., Data Extraction: All clinical trials that were available prior to submission of this manuscript for publication, including unpublished reports, were reviewed., Data Synthesis: The human insulin analog, insulin lispro, which is biosynthetically made by inverting the amino acid sequence of human insulin at B-28 and B-29, is more effective than regular human insulin in improving postprandial glucose control. Subcutaneous injections of insulin lispro result in decreased blood glucose peaks following meals and a potential decreased risk of hypoglycemic episodes, including nighttime hypoglycemia in patients with type 1 diabetes. Insulin lispro in comparison with regular human insulin provides equal or slightly better blood glucose control. When compared with subcutaneous injections of regular human insulin, the peak serum insulin concentration of insulin lispro is three times higher, time to peak is 4.2 times faster, the absorption rate constant is double, and the duration of action is half as long. Insulin lispro is similar to regular human insulin with reference to dose, toxicity, adverse effects, drug interactions, and immunogenicity. When insulin lispro is mixed with human NPH (isophane) or Lente insulins, insulin lispro should be drawn into the syringe first, mixed with the long-acting insulin, and injected immediately after mixing. Patients using insulin lispro perceive an improvement in their well-being and quality of life due to flexible injection times and less frequent hypoglycemic reactions. Insulin lispro is believed to be suitable for patients using insulin infusion pumps., Conclusions: Insulin lispro is equipotent to human insulin and has a much more rapid onset and shorter duration of action than human insulin does, which may reduce the risk of hypoglycemia. In addition, insulin lispro improves the dosing convenience for patients with diabetes and provides a more natural control of blood glucose concentrations. Insulin lispro is a useful new agent in the treatment of diabetes mellitus.

Objectives: To review the clinical pharmacology of acarbose, an alpha-glucosidase inhibitor, and to summarize its role in the pharmacotherapy of diabetes mellitus., Data Sources: A MEDLINE search identified all relevant articles, including reviews; Bayer Pharmaceuticals., Study Selection: Due to the large number of clinical trials available, specific criteria were used to narrow the focus of this review: (1) randomized, double-blind, placebo-controlled, parallel-group study design; (2) a minimum of 25 patients enrolled per treatment arm; (3) a treatment duration of 90 days or more; and (4) adherence to Food and Drug Administration Good Clinical Practice guidelines., Data Extraction: All clinical trials that were available up to December 1995 were reviewed. Preliminary trials and unpublished reports were not reviewed., Data Synthesis: Acarbose is effective in reducing postprandial hyperglycemia. It does not stimulate endogenous insulin secretion and, therefore, will not cause hypoglycemia when used as monotherapy. The enhanced glycemic control achieved with acarbose is additive to that of sulfonylureas. It lowers postprandial serum glucose and insulin concentrations and does not promote weight gain. Acarbose can be used as first-line therapy with diet and exercise, or it can be used in combination with sulfonylureas to lower hemoglobin A1c concentrations an additional 0.5-0.9%. Acarbose is not a cure for diabetes, nor is it a substitute for diet, exercise, oral hypoglycemic agents, or insulin. Adverse effects are gastrointestinal and can be diminished by starting with an initial dosage of 25 mg tid. Depending on patient response, the dosage can be increased up to a maximum of 100 mg tid over time., Conclusions: Acarbose, through its unique mechanism of action, appears to be a safe and effective adjunctive agent to diet/exercise therapy or sulfonylurea therapy for treatment of non-insulin-dependent diabetes mellitus.

Streptococcus mutans Ingbritt grown under standardized conditions adhered less effectively to saliva-coated hydroxyapatite beads than did Streptococcus sanguis G9B, and there was competition for binding. The results with Ingbritt were influenced by the generation time, the pH of growth, and the carbohydrate source as shown by studies on organisms grown in continuous culture.

Lactobacillus fermentum NCTC 6991 and Lactobacillus plantarum NCIB 7220 were grown in a chemostat in the diffusible fraction of complex medium at pH 6.0 with glucose limitation. Organisms grown at different dilution rates (D) were injected into rabbits, and the resultant antisera were examined for reactivity with antigens previously isolated from batch-grown organisms. For L. fermentum, antisera obtained on injecting cells grown at D = 0.5 h-1 contained a significantly higher level of antibody reacting with lipoteichoic acid and a lower level of antibody reacting with wall polysaccharide than did antisera obtained with slower-growing cells (D = 0.05 and 0.033). Antibodies to the cell wall polysaccharide were alpha-D-glucosyl specific and cross-reacted with dextran and alpha-D-glucosyl ribitol teichoic acid from L. plantarum. The immunogenicity of the ribitol teichoic acid and lipoteichoic acid components of L. plantarum was not influenced by injecting organisms grown at different rates. However, chemical and serological studies indicate that growth of L. plantarum in the diffusible fraction of complex medium results in a wall teichoic acid of lower glucose substitution. This apparently influences the specificity of the resultant antibodies so that some sera react much less with glucosyl-substituted lipoteichoic acid and dextran.

To examine the question of whether or not the genetic code has a stereochemical basis, we used artificial constructs of the topography and physicochemical features of unique "cavities" formed by removal of the second codon base in B-DNA. The effects of base changes on the stereochemistry of the cavities are consistent with the pattern of the genetic code. Fits into the cavities of the side chains of the 20 L amino acids involved in protein synthesis can be demonstrated by using conventional physicochemical principles of hydrogen bonding and steric constraints. The specificity of the fits is remarkably consistent with the genetic code.

We examined the effect of growth conditions in chemostat culture on the quantity and composition of the cell wall teichoic acids of Streptococcus mutans BHT and Lactobacillus plantarum NCIB 7220 and the membrane lipoteichoic acid from S. mutans Ingbritt. With the cell wall teichoic acids, which are covalently linked to peptidoglycan, the amount of teichoic acid is independent of the growth conditions employed. However, the extent of glucosyl substitution of the polymer from L. plantarum was dependent on growth conditions. S. mutans Ingbritt lipoteichoic acid, on the other hand, was little affected by growth conditions in terms of composition or serological activity, but the amount produced was markedly affected by changes in growth conditions.

Immunological assays with antisera prepared against purified Streptococcus mutans serotype c polysaccharide demonstrated that a cross-reacting determinant on c polysaccharide reacted with the wall-associated rhamnose-glucose polysaccharide from S. mutans serotype d. Studies with 60 antisera prepared against chemostat cultures of S. mutans Ingbritt (c) demonstrated that the rhamnose-glucose polysaccharide cross-reactive determinant was consistently expressed on c antigen under a variety of growth conditions.

Bacteria may respond to changes in their environment by varying the synthesis of surface components. This study examined the effects of various culture conditions on two wall polysaccharides of Streptococcus mutans B13 (serotype d): serotype d antigen, a galactose-glucose polymer, and RGP antigen, a rhamnose-glucose polymer. Cells were grown in a chemostat at various dilution rates (D) and pH values, including D = 0.05, 0.1, and 0.5 h-1 at pH 6.0 and D = 0.1 h-1 at pH 5.5, 6.0, 6.5, and 7.5. The cells were examined for protein and carbohydrate content by colorimetric assays and gas-liquid chromatography. Rantz-Randall extracts (120 degrees C, 30 min) and M-1 N-acetylmuramidase digests were prepared and examined for the presence of specific antigens by agar gel diffusion and quantitative precipitation assays. Cell preparations did not vary significantly with respect to total protein or carbohydrate content; however, cells grown at D = 0.1 h-1 and pH 7.5 had a significantly higher rhamnose content than did the other preparations. Rapidly growing cultures appeared to be more resistant to M-1 N-acetylmuramidase digestion than did slower-growing cultures. Agar gel diffusion studies demonstrated that both serotype d and RGP antigens were present in all samples, although significantly less RGP antigen was noted in the pH 7.5 culture. These observations were confirmed by quantitative precipitation assays. M-1 N-acetylmuramidase digests of the pH 7.5 culture were lacking in RGP precipitation activity although RGP inhibition activity was demonstrated. The data suggest that the cell content of serotype d antigen was relatively constant under the growth conditions tested, whereas the synthesis of RGP antigen was modified under conditions of high pH.

Quantitative analyses of cell walls from Streptococcus mutans Ingbritt grown under carbohydrate limitation in the chemostat showed that growth conditions had no statistically significant effect on the composition of polysaccharide, peptidoglycan, or the proportion of polysaccharide in the cell wall. Lysis of cell wall preparations with a muramidase supported this conclusion and further indicated that there was little difference in their overall structure. In contrast, there was a consistent difference between the rates of lysis by this enzyme of organisms grown in 0.2% glucose and 0.5% glucose. Extremes of pH or dilution rate essentially did not influence the immunogenicity of type c antigen in whole organisms irrespective of whether the carbohydrate source was glucose or sucrose. However, differences were found in the immunogenicity of lipoteichoic acid under similar circumstances. The results indicated there was an inherent phenotypic stability in the cell walls of S. mutans Ingbritt despite changes in pH, generation time, and carbohydrate source, and that any changes that did occur were probably due to associated cell-surface components.

Lysis of cell wall preparations from strains representing serotypes a - g of Streptococcus mutans has provided a convenient and efficient means of obtaining the typing antigens in a soluble undegraded form, and has demonstrated that, in each case, the antigen is a cell wall component in the strict sense of a component joined covalently to peptidoglycan. This influences the choice of extraction procedures.

The group G antigen of lactobacilli was identified as a negatively-charged cell wall polysaccharide. The components of the preparation isolated from cell walls of L. salivarius subsp. salivarius by mild acid hydrolysis were glucose, galactose and lesser amounts of rhamnose, N-acetylglucosamine and phosphate. Quantitative serological studies on acid-released polysaccharide and enzymic lysates of cell walls showed that rhammose was the immunodominant component. The antigen was also detected in L. salivarius subsp. salicinus but not in a recent isolate of L. salivarius, strain IV CL-37.

Strains of Lactobacillus casei subsp. rhamnosus possessing two cell wall polysaccharides, a hexosamine-containing H-polysaccharide and a rhamnose-containing R-polysaccharide, were examined for the effect of growth conditions on the production of these two components. In strain NCTC 6375, R- and H-polysaccharides accounted for an estimated 44 and 20%, respectively, of the cell wall for organisms grown in batch culture with glucose as the carbohydrate source. Growth on fructose-containing media reduced the amount of R-polysaccharide by approximately 50% without affecting the amount of H-polysaccharide. Subculture of fructose-grown organisms in glucose restored the original proportions of the two polysaccharides. Galactose- and sucrose-grown cells behaved similarly to glucose-grown cells with respect to polysaccharide production, whereas growth in rhamnose or ribose showed values close to those for fructose-grown cells. Continuous culture of strain NCTC 6375 for more than 100 generations showed a gradual and irreversible reduction of the R-polysaccharide to less than 5% of the cell wall and an increase of the H-polysaccharide to 40% of the cell wall. Other type culture strains of L. casei subsp. rhamnosus, NCIB 7473 and ATCC 7469, behaved similarly in batch and continuous culture. In contrast, strains of L. casei subsp. rhamnosus isolated at the Institute of Dental Research showed phenotypic stability with respect to the relative proportions of R- and H-polysaccharides in both batch and continuous culture. Changes in polysaccharide composition of type culture strains were also mirrored in changes in the immunogenicity of the two components and resistance to the rate of enzymic lysis of whole organisms. For L. casei subsp. rhamnosus strain NCTC 10302 the R-polysaccharide is present entirely as capsular material. The amount of R-polysaccharide produced was also markedly dependent on the carbohydrate component of the medium in batch culture and both dilution rate and nature of the limiting carbohydrate in continuous culture, varying over a 10-fold range, whereas the cell wall H-polysaccharide remained constant.

Streptococcus mutans Ingbritt was grown in a chemostat at destined dilution rates in either 0.5% fructose or 0.5% sorbitol and at destined pH values in 0.5% fructose. The yield of cells was affected by the carbohydrate source, as well as by the pH, with the lowest yield being at pH 5.5 in 0.5% fructose. Fructose-grown cells showed greater susceptibility to lysis by a muramidase than the corresponding glucose-grown cells, but there were no marked differences in the lytic susceptibilities of the corresponding cell wall preparations or in the serological reactivities of wall lysates with antiserum to S. mutans Ingbritt. The greatest amounts of cellular lipoteichoic acid were obtained at high dilution rates in both fructose and sorbitol, as well as at high pH values in fructose. The greatest amounts of extracellular lipoteichoic acid were found at low dilution rates, as estimated by rocket immunoelectrophoresis and also by hemagglutination. Three major extracellular protein components were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the effects of growth conditions on these components were determined. Results for batch-grown cultures showed that there was genotypic variation in the susceptibility of cells to lysis by a muramidase. The enhancement of lipoteichoic acid production by fructose and sorbitol in batch cultures was not identical in representative strains of S. mutans serotype c, nor was the effect of fructose found uniformly in representative strains of the different S. mutans serotypes.

The shape of the space occupied by a model of the estrogenic steroid hormone estradiol-17 beta conforms closely to a helical cavity between neighboring base pairs in partially coiled B-DNA. The orientation of estradiol-17 beta when fitted into DNA allows stereochemically complementary hydrogen bonding of both the 3- and 17 beta-hydroxyl groups to phosphate oxygens of the deoxyribose-phosphate backbone on adjacent strands. Changes in the chirality (handedness) of the steroid skeleton or in the absolute stereochemistry of hydrogen bonding groups prevent formation of complementary fits in the DNA. Synthetic estrogens can also adopt conformations which are stereochemically complementary to the cavities between base pairs. The complementary relationships between active estrogens and nucleic acids may be related to constraints on the evolution of the structure and the biological function of steroids.

Streptococcus sanguis is a major component of early dental plaque. The ability of S. sanguis to adhere to salivary pellicle appears to involve specific bacterial surface receptors. The nature of these receptors is still not known; however, the component molecules may be subject to environmental control as has been shown for teichoic acids and certain proteins. To study these environmental effects, a chemostat was employed to vary the growth conditions of Streptococcus sanguis strain G9B. This strain has been used extensively to study the adhesion of [(3)H]thymidine-labeled batch-grown cells to saliva-coated hydroxyapatite beads. The effects of dilution rate, pH, and carbon source on adhesion were studied with a competition assay in which the labeled batch cells were used as a reference standard. In this assay, cells from the chemostat were harvested and compared for their ability to inhibit adhesion of labeled cells relative to unlabeled control batch-grown cells. Subsequent studies used chemostat grown cells labeled with [(3)H]thymidine as a reference standard so that results were internally controlled and reflected only the particular alteration in environment which was studied. These results indicated that when glucose was used as a growth-limiting substrate, cells grown at relatively high dilution rates (D = 0.5 h(-1); mean generation time = 1.4 h) behaved similarly to batch-grown cells and appeared to compete for the same binding sites. Cells grown at D = 0.1 h(-1) (mean generation time = 7 h) no longer competed with either batch-grown cells or chemostat cells grown at D = 0.5 h(-1). Moreover, adsorption isotherms of such slow-growing cells (D = 0.1 h(-1)) suggested that binding was no longer specific. When fructose was used as the growth-limiting carbohydrate, cells grown at D = 0.1 h(-1) did not show this loss of specificity and competed nearly as well as control batch-grown glucose cells. However, the effect of pH appeared to be independent of carbohydrate source, because cells grown in either glucose or fructose at pH 5.5 at D = 0.1 h(-1) lost the ability to compete with reference batch or chemostat cells grown at D = 0.5 h(-1). This effect was very sharp, since cells grown in the pH range from 6 to 7.5 at D = 0.5 h(-1) competed nearly as well as control cells. A similar effect of pH was found for batch cultures grown with excess glucose. These studies reinforce the idea that the environment can profoundly affect the bacterial surface and consequently the ability of the organism to adhere, a property which appears to be a primary event in some infectious diseases and in dental plaque formation.

Streptococcus mutans Ingbritt was grown in a chemostat at defined dilution rates and pH values and under carbohydrate limitation. At a constant dilution rate of D = 0.1 h-1 and with either 0.5% glucose or 0.5% sucrose, the amounts of both cellular and extracellular lipoteichoic acid increased as the culture pH increased from 5.0 to 7.5. At a constant pH of 6.0, the amount of cellular lipoteichoic acid formed by cultures growing in 0.2% or 0.5% glucose was relatively constant over a range of dilution rates, although the amount of extracellular lipoteichoic acid formed in 0.2% glucose at intermediate dilution rates was less than that formed in 0.5% glucose. Organisms grown in 0.5% sucrose at pH 6.0 contained increasing amounts of cellular lipoteichoic acid as the dilution rate was increased. A comparison of the amounts of cellular lipoteichoic acid formed by organisms growing at D = 0.5 h-1 and pH 6.0 in glucose, sucrose, fructose, or mixtures of glucose and fructose in limiting amounts suggested that the enhanced production of lipoteichoic acic by sucrose-grown organisms was due to the fructose component. The culture fluids from both glucose- and sucrose-grown organisms contained detectable amounts of serotype c antigen, whereas glucose-grown cultures also contained significant amounts of an extracellular hexose-containing polymer.

Autoclaving cell wall of Streptococcus mutans Ingbritt for 15 min under the Rantz and Randall conditions released one-tenth of the total cell wall carbohydrate, whereas two-thirds was extracted after autoclaving for 180 min. The extract contained the serotype c-specific antigen but lacked the lipoteichoic acid component extracted when whole cells were autoclaved. Autoclaving cell wall preparations from other strains of S. mutans and also Streptococcus salivarius and Streptococcus mitis in 0.85% NaCl for 180 min released the major proportion of the wall polysaccharide fraction. Approximately 50 to 90% of wall carbohydrate of Lactobacillus fermentum and Lactobacillus casei was released when cell wall preparations were autoclaved in 0.85% NaCl for 180 min. For wall preparations from several strains of S. mutans, autoclaving for 60 min at pH 3.75 released only 39 to 62% of wall carbohydrate, whereas almost total release could be achieved with the lactobacilli. Heating S. mutans Ingbritt cell wall for 24 h at 60 degrees C in 0.1 N H(2)SO(4) released only two-thirds of the wall carbohydrate; by comparison nearly all of the wall carbohydrate was released in 3 h from L. casei and L. fermentum. Autoclaving L. casei cell wall and purified soluble wall fractions hydrolyzed the phosphodiester bond between the polysaccharide and peptidoglycan. This was shown by the release of reactive N-acetylhexosamine in both cases and the presence of a phosphomonoester in the autoclaved soluble wall fractions. The results indicate that autoclaving can hydrolyze covalent linkages, and this must be considered when the Rantz and Randall procedure is used to obtain antigen preparations.