Search

Objectives: There is controversy over who should serve as the Trauma Team Leader (TTL) at trauma-receiving centres. This study compared survival and emergency department (ED) length-of-stay between patients cared for by 3 different groups of TTLs: surgeons, emergency physicians (EPs) on call for trauma cases and EPs on shift in the ED.Methods: We performed a retrospective cohort study involving all adult major blunt trauma patients (aged 17 and older) who were admitted to 2 level I trauma centres and who were entered into a provincial Trauma Registry between March 2000 and April 2002. The study was designed to compare the effect of TTL-type on survival and ED length-of-stay, while controlling for sex, age, and trauma severity as defined by the Injury Severity Score (ISS) and the Revised Trauma Score (RTS). Analysis was performed using linear regression modeling (for the ED lenght-of-stay outcome variable), and logistic regression modeling (for the surivial outcome variable).Results: There were 1412 patients enrolled in the study. The study population comprised 74% men and 26% women, with a mean age of 44.7 years (43.1, 46.6 and 42.8 years for surgeons, on-call EPs and on-shift EPs, respectively). The overall mean ISS was 23.2 (23.7 for surgeons, 22.9 for on-call EPs and 23.3 for on-shift EPs) and the overall average RTS was 7.6 (7.6 for surgeons, 7.6 for on-call EPs and 7.5 for on-shift EPs). The overall median ED length-of-stay was 5.3 hours (4.5, 5.3 and 5.6 hours for surgeons, on-call EPs and on-shift EPs, respectively; p = 0.07) and the overall survival was 87% (86% surgeon, 88% on-call EP, 87% on-shift EP; p = 0.08). No statistically significant relationship was found between TTL-type and ED length-of-stay (p = 0.42) or survival (p = 0.43) using multivariate modeling.Conclusion: Our results suggest that surgeons, on-call EPs, or on-shift EPs can act as the TTL without a negative impact on patient survival or ED length-of-stay. [ABSTRACT FROM AUTHOR]

X-ray opacity measurements on the National Ignition Facility (NIF) are in the process of reproducing earlier measurements from the Sandia Z Facility, in particular for oxygen and iron plasmas. These measurements have the potential to revise our understanding of the "solar problem" and of the hot degenerate Q class white dwarf structure by probing plasma conditions near the base of their convection zones. Accurate opacity measurements using soft x-ray Bragg crystal spectrometers require correction for higher-order diffraction effects. Extending prior work in this area [Dutra et al., Review of Scientific Instruments 93, 113527 (2022)], we have developed a new method to remove higher-order spectral components from NIF opacity spectrometer data. By modeling absorption and backlighting continuum spectra and subtracting the second- and third-order components from the measured data, we are able to perform this correction while avoiding imprinting first-order model line features onto the data., (© 2024 Author(s). Published under an exclusive license by AIP Publishing.)

A new time-resolved opacity spectrometer (OpSpecTR) is currently under development for the National Ignition Facility (NIF) opacity campaign. The spectrometer utilizes Icarus version 2 (IV2) hybridized complementary metal-oxide-semiconductor sensors to collect gated data at the time of the opacity transmission signal, unlocking the ability to collect higher-temperature measurements on NIF. Experimental conditions to achieve higher temperatures are feasible; however, backgrounds will dominate the data collected by the current time-integrating opacity spectrometer. The shortest available OpSpecTR integration time of ∼2 ns is predicted to reduce self-emission and other late-time backgrounds by up to 80%. Initially, three Icarus sensors will be used to collect data in the self-emission, backlighter, and absorption regions of the transmission spectrum, with plans to upgrade to five Daedalus sensors in future implementations with integration times of ∼1.3 ns. We present the details of the diagnostic design along with recent characterization results of the IV2 sensors., (© 2024 Author(s). Published under an exclusive license by AIP Publishing.)

Accurate understanding of x-ray diagnostics is crucial for both interpreting high-energy-density experiments and testing simulations through quantitative comparisons. X-ray diagnostic models are complex. Past treatments of individual x-ray diagnostics on a case-by-case basis have hindered universal diagnostic understanding. Here, we derive a general formula for modeling the absolute response of non-focusing x-ray diagnostics, such as x-ray imagers, one-dimensional space-resolved spectrometers, and x-ray power diagnostics. The present model is useful for both data modeling and data processing. It naturally accounts for the x-ray crystal broadening. The new model verifies that standard approaches for a crystal response can be good approximations, but they can underestimate the total reflectivity and overestimate spectral resolving power by more than a factor of 2 in some cases near reflectivity edge features. We also find that a frequently used, simplified-crystal-response approximation for processing spectral data can introduce an absolute error of more than an order of magnitude and the relative spectral radiance error of a factor of 3. The present model is derived with straightforward geometric arguments. It is more general and is recommended for developing a unified picture and providing consistent treatment over multiple x-ray diagnostics. Such consistency is crucial for reliable multi-objective data analyses., (© 2023 Author(s). Published under an exclusive license by AIP Publishing.)

The Opacity Platform on the National Ignition Facility (NIF) has been developed to measure opacities at varying densities and temperatures relevant to the solar interior and thermal cooling rates in white dwarf stars. The typical temperatures reached at NIF range between 150 and 210 eV, which allow these measurements to be performed experimentally. The captured opacities are crucial to validating radiation-hydrodynamic models that are used in astrophysics. The NIF opacity platform has a unique new capability that allows in situ measurement of the sample expansion. The sample expansion data are used to better understand the plasma conditions in our experiments by inferring the sample density throughout the duration of the laser drive. We present the details of the density measurement technique, data analysis, and recent results for Fe and MgO.

Plasma density measurements are key to a wide variety of high-energy-density (HED) and laboratory astrophysics experiments. We present a creative application of photonic Doppler velocimetry (PDV) from which time- and spatially resolved electron density measurements can be made. PDV has been implemented for the first time in close proximity, ∼6 cm, to the high-intensity radiation flux produced by a z-pinch dynamic hohlraum on the Z-machine. Multiple PDV probes were incorporated into the photoionized gas cell platform. Two probes, spaced 4 mm apart, were used to assess plasma density and uniformity in the central region of the gas cell during the formation of the plasma. Electron density time histories with subnanosecond resolution were extracted from PDV measurements taken from the gas cells fielded with neon at 15 Torr. As well, a null shot with no gas fill in the cell was fielded. A major achievement was the low noise high-quality measurements made in the harsh environment produced by the mega-joules of x-ray energy emitted at the collapse of the z-pinch implosion. To evaluate time dependent radiation induced effects in the fiber optic system, two PDV noise probes were included on either side of the gas cell. The success of this alternative use of PDV demonstrates that it is a reliable, precise, and affordable new electron density diagnostic for radiation driven experiments and more generally HED experiments.

We report experimental and modeling results for the charge state distribution of laboratory photoionized neon plasmas in the first systematic study over nearly an order of magnitude range of ionization parameter ξ∝F/N_{e}. The range of ξ is achieved by flexibility in the experimental platform to adjust either the x-ray drive flux F at the sample or the electron number density N_{e} or both. Experimental measurements of photoionized plasma conditions over such a range of parameters enable a stringent test of atomic kinetics models used within codes that are applied to photoionized plasmas in the laboratory and astrophysics. From experimental transmission data, ion areal densities are extracted by spectroscopic analysis that is independent of atomic kinetics modeling. The measurements reveal the net result of the competition between photon-driven ionization and electron-driven recombination atomic processes as a function of ξ as it affects the charge state distribution. Results from radiation-hydrodynamics modeling calculations with detailed inline atomic kinetics modeling are compared with the experimental results. There is good agreement in the mean charge and overall qualitative similarities in the trends observed with ξ but significant quantitative differences in the fractional populations of individual ions.

We discuss the experimental and modeling results for the x-ray heating and temperature of laboratory photoionized plasmas. A method is used to extract the electron temperature based on the analysis of transmission spectroscopy data that is independent of atomic kinetics modeling. The results emphasized the critical role of x-ray heating and radiation cooling in determining the energy balance of the plasma. They also demonstrated the dramatic impact of photoexcitation on excited-state populations, line emissivity, and radiation cooling. Modeling calculations performed with astrophysical codes significantly overestimated the measured temperature.

Median raphe cyst is an uncommon developmental anomaly that can develop anywhere along the midline of the external genitals. Only a few hundred cases have been published in the English literature and the lack of awareness of this entity can lead to confusion and misdiagnosis. We report here a case of median raphe cyst located in the midline of the anterior scrotum of a 35- year-old man. Clinically, the patient presented with a scrotal mass increasing substantially in size over two days associated with tenderness, skin erythema, and scrotal pain. Radiologic interpretation of a sonogram and computed tomography scan suggested a thrombosed vessel. The patient was diagnosed with septic thrombophlebitis associated with overlying cellulitis. Despite conservative therapy with antibiotics, the patient developed pyrexia, tachycardia, and leukocytosis prompting surgical excision of the lesion. Histopathologic examination revealed an infected median raphe cyst. The cyst wall was lined by a stratified epithelium that included numerous Alcian blue positive goblet cells. The epithelial cells showed reactive changes with infiltration by numerous neutrophils. Our objective is to bring attention to and thereby facilitate the diagnosis of this unusual entity., Competing Interests: Conflict of interest: the authors declare no potential conflict of interest., (©Copyright: the Author(s), 2019.)

Background: Electronic documentation handling may facilitate information flows in health care settings to support better coordination of care among Health Care Providers (HCPs), but evidence is limited. Methods that accurately depict changes to the workflows of HCPs are needed to assess whether the introduction of a Critical Care clinical Information System (CCIS) to two Intensive Care Units (ICUs) represents a positive step for patient care. To evaluate a previously described method of quantifying amounts of time spent and interruptions encountered by HCPs working in two ICUs., Methods: Observers used PDAs running the Work Observation Method By Activity Timing (WOMBAT) software to record the tasks performed by HCPs in advance of the introduction of a Critical Care clinical Information System (CCIS) to quantify amounts of time spent on tasks and interruptions encountered by HCPs in ICUs., Results: We report the percentages of time spent on each task category, and the rates of interruptions observed for physicians, nurses, respiratory therapists, and unit clerks. Compared with previously published data from Australian hospital wards, interdisciplinary information sharing and communication in ICUs explain higher proportions of time spent on professional communication and documentation by nurses and physicians, as well as more frequent interruptions which are often followed by professional communication tasks., Conclusions: Critical care workloads include requirements for timely information sharing and communication and explain the differences we observed between the two datasets. The data presented here further validate the WOMBAT method, and support plans to compare workflows before and after the introduction of electronic documentation methods in ICUs.

Electronic documentation methods may assist critical care providers with information management tasks in Intensive Care Units (ICUs). We conducted a quasi-experimental observational study to investigate patterns of information tool use by ICU physicians, nurses, and respiratory therapists during verbal communication tasks. Critical care providers used tools less at 3 months after the CCIS introduction. At 12 months, care providers referred to paper and permanent records, especially during shift changes. The results suggest potential areas of improvement for clinical information systems in assisting critical care providers in ensuring informational continuity around their patients.

Objective: to evaluate the influence of initial oligohydramnios on the prognosis of women with preterm premature rupture of the membranes (PPROM) at 30 to 36 weeks' gestation., Methods: the Royal Alexandra Hospital ultrasound database was used to identify singleton pregnancies at 30 to 36 weeks' gestation with an ultrasound performed for confirmed PPROM from January 1992 to December 2006. Records were linked to the electronic provincial delivery record to perform a retrospective cohort study comparing the outcomes of pregnancies with an initial amniotic fluid index (AFI) < 5 cm with the outcomes of pregnancies with an AFI of 5 to 10 cm. Logistic and linear regression were used to analyze the association between binary outcome and explanatory variables., Results: the maternal and perinatal outcomes of 438 pregnancies were analyzed. Univariate analysis suggested statistically significant associations between initial oligohydramnios and decreased latency (P < 0.001), increased histologically proven chorioamnionitis (P = 0.01), neonatal length of stay in hospital (P = 0.002), and NICU (P = 0.003); however, after controlling for confounding variables (gestational age at delivery, parity, presentation, and antenatal antibiotic and corticosteroid administration), only latency remained significant (P = 0.004). No association was found between initial oligohydramnios and any other outcomes assessed, including mode of delivery, postpartum endometritis, maternal length of stay, non-reassuring fetal status, and neonatal morbidity and mortality., Conclusion: initial oligohydramnios is associated with decreased latency in singleton pregnancies complicated by PPROM at 30 to 36 weeks' gestation; however, it does not appear to influence maternal or neonatal infectious morbidity, and it may not be useful to determine candidacy for expectant management or intentional delivery.

The histopathologic distinction between pigmented actinic keratosis (PAK) and atypical junctional melanocytic proliferations (AJMP) is a common problem, and it is one with meaningful clinical significance. Previous publications have suggested that Melanocyte Antigen Related to T-cells-1 (MART-1)--a melanocytic marker related to host immune response--was not useful in making this interpretative separation. To revisit that assertion, the authors selected 68 specimens that concerned the diagnosis of PAK vs. AJMP. The degree of morphologic difficulty attached to each case was rated semiquantitatively using a three-tiered scale, and interpretative problems were caused by cytologic similarity between atypical keratinocytes and aberrant melanocytes, obscuring lichenoid inflammation, subepidermal fibrosis, and an absence of clearly defined cell nests at the dermoepidermal junction. Each biopsy sample was immunostained for MART-1 (using antibody clone A103) with azure-B counterstaining; the principal criterion for a diagnosis of AJMP was that of confluent cellular positivity over at least 1 high-power (x400) microscopic field, in conjunction with nested cell growth. The specimens were then re-examined diagnostically. Immunostaining definitely improved interpretative certitude in 65 examples (96% effectiveness); the final diagnosis was that of PAK for 21 lesions and AJMP for 47. Three specimens--all of which represented AJMP--did not benefit by MART-1 staining. It is concluded that MART-1 immunostaining with azure-B counterstaining is a useful adjunct in the interpretation of problematic intra-epidermal pigmented lesions.

alpha-Methylacyl-coenzyme A racemase (AMACR) has become a common tool in the diagnosis of morphologically difficult prostatic carcinoma and often is used in combination with the basal cell markers p63 and 34betaE12. Outside this context, applications have been limited. Although initially considered a specific marker of prostatic carcinoma, immunoreactivity for AMACR has been found in a variety of other neoplasms. We report findings in 21 cases of extramammary Paget disease (EMPD), a neoplasm not previously reported to show AMACR immunoreactivity. We found immunoreactivity for AMACR in 15 (71%) of 21 EMPD cases overall, in 5 (56%) of 9 cases in women, and in 10 (83%) of 12 cases in men. AMACR immunoreactivity is a common finding in EMPD in men and women.

Disorders of the respiratory system, such as cystic fibrosis (CF), involve the infiltration and activation of airway inflammatory cells, including neutrophils. This leads to the secretion of peroxidases, which react further with substrates in solution to produce oxidative metabolites, such as 3-chlorotyrosine. Elevated levels of modified tyrosine residues in the airways of patients with CF may be detectable by nuclear magnetic resonance (NMR) in correlation with inflammatory cell influx. In this study, high-resolution (500 MHz) 1H NMR was used to analyze the production of modified tyrosine residues resulting from in vitro stimulation of peripheral blood eosinophils and neutrophils, as well as in sputum samples from control subjects and patients with CF. Following in vitro stimulation, purified peripheral blood neutrophils generated 3-chlorotyrosine, while eosinophils produced predominantly 3-bromotyrosine and 3,5-dibromotyrosine. Chlorinated and brominated tyrosine residues were detected in sputum samples from patients with CF (N=7), but were not detected in the control group (N=9). Neutrophil counts in CF sputum correlated strongly with the presence of 3-chlorotyrosine (r2=0.869). Our findings indicate that neutrophil and eosinophil activation in CF is detectable by NMR. NMR may be a useful tool for the detection of biological markers of inflammatory processes in patient airways.

This study examined whether emergency physicians (EPs) exposed to multiple dissemination strategies for the Ottawa Ankle Rules (OARs) would reduce extremity radiography use. We conducted a prospective cohort study comparing intervention (n = 2) with control (n = 2) hospitals over a 2-year period. All EPs received the paper-based rules during the run-in phase; EPs in the intervention hospitals were also subjected in sequence to valid dissemination approaches. Provincewide dissemination of the OARs did not decrease radiography during the run-in period (92% vs. 93%; P =.36). Sequential directed education and personalized feedback strategies failed to reduce radiographic ordering rates (P =.54) or the ordering of both foot and ankle radiographs (P =.11) over time. The use of radiography did not decrease despite the use of a variety of dissemination strategies. Additional research is required to determine the most effective methods of incorporating guidelines into emergency practice.

Objective: To explore the relationship between maternal obesity and shoulder dystocia while controlling for the potential confounding effects of other variables associated with obesity., Methods: We performed a case-control study of provincial delivery records audited by the Northern and Central Alberta Perinatal Outreach Program. Risk factors evaluated were selected based on previously published studies. Cases and controls were drawn from 45,877 live singleton cephalic vaginal deliveries weighing more than 2500 g between January 1995 and December 1997. There were 413 cases of shoulder dystocia (0.9% incidence). Controls (n = 845) were randomly chosen from the remainder of the target population to create a 1:2 case/control ratio. Univariate analysis with calculation of odds ratios (ORs) was used to determine which of the chosen risk factors were significantly related to the incidence of shoulder dystocia. Multivariable regression analyses were then used to determine the independently associated variables, and the adjusted ORs were obtained for each relevant risk factor., Results: Maternal obesity was not significant as an independent risk factor for shoulder dystocia after adjusting for confounding variables (adjusted OR 0.9; 95% confidence interval [CI] 0.5, 1.6). Fetal macrosomia was the single most powerful predictor. The adjusted ORs were 39.5 (95% CI 19.1, 81.4) for birth weight greater than 4500 g and 9.0 (95% CI 6.5, 12.6) for birth weight between 4000 and 4499 g., Conclusion: The strongest predictors of shoulder dystocia are related to fetal macrosomia. For obese nondiabetic women carrying fetuses whose weights are estimated to be within normal limits, there is no increased risk of shoulder dystocia.

Objective: The purpose of this study was to compare early oral intake and the traditional timing of feeding after major gynecologic surgery and the effects on the length of hospital stay., Study Design: Gynecologic oncology and urogynecology patients who underwent major abdominal gynecologic surgery were prospectively randomized to 1 of 2 groups. The traditional feeding group (group A, 49 patients) received nothing by mouth until documentation of bowel function. They were then advanced slowly to solid diet. The patients allocated to the early feeding regimen (group B, 47 patients) began clear fluids on the first postoperative day. Once 500 mL of clear fluid was tolerated, they received a regular diet. The groups were compared with regard to length of hospital stay, postoperative day that solids were tolerated, and the incidence of adverse effects. Statistical analyses were performed with the chi(2) test, the Fisher exact test, the Student t test, and analysis of variance., Results: The demographic characteristics of the 2 groups were similar. There was a statistically significant reduction in the length of hospital stay for those patients on the early feeding regimen. The median length of stay for group A was 6.0 days and for group B was 4.0 days (P =.0001). There was no difference in the incidence of emesis, ileus, or other postoperative complications between the 2 groups., Conclusion: Early postoperative dietary advancement after major abdominal gynecologic surgery results in a decreased length of hospital stay and appears to be safe, with no increased adverse effects.

Objective: To determine the incidence of maternal cell contamination (MCC) in the open-needle amniocentesis sampling technique compared with the trocar-in-place technique., Methods: A retrospective analysis was conducted on 2,498 mid-trimester amniocenteses performed in two tertiary care centres in Canada. The University of Alberta centre used the open-needle (without the trocar) technique and the University of British Columbia centre used the standard (with the trocar in place) technique. Data were gathered regarding the nature of the amniotic fluid, number of needle passes, amniocentesis results, and the occurrence of maternal cell contamination. The statistical analysis used logistic regression, and controlled for the potential confounders of bloody fluid taps and requirement for more than one needle insertion., Results: The incidence of maternal cell contamination was 1.16% with the open-needle technique and 0.78% with the standard trocar-in-place technique (p < 0.315), with a power of 42%., Conclusion: The data suggested there is no significant increase in maternal cell contamination with the open-needle versus trocar-in-place techniques of amniocentesis. However, the small sample size, combined with the low prevalence of the outcome of interest (MCC), provides insufficient power to draw firm conclusions about the difference in MCC between the two techniques.

A model for foetal growth is developed and used to construct tools for diagnosis of intrauterine growth restriction. Foetal weight estimates are first transformed to normally distributed z-scores. The covariance structure over gestational ages is then estimated using a novel regression model. The diagnostic tools include individual growth curves with error bounds, probabilities to assess whether a foetus is small for its gestational age, and residual scores to determine whether current growth rates are unusual. The methods were developed sing data from 13593 ultrasound examinations involving 7888 foetal subjects. The model shows that median foetal growth velocity increases up to a gestational age of 35 weeks and then decreases during the final weeks of pregnancy. When growth is expressed as change in log weight, or equivalently as change proportional to current weight, the model reveals a constant deceleration as gestational age increases from 14 to 42 weeks., (Copyright 2002 John Wiley & Sons, Ltd.)

Objective: To study the relationship between maternal smoking and preeclampsia and whether this association differs between primiparous and multiparous women., Study Design: We conducted a population-based, retrospective, cohort study of 58,216 singleton pregnancies from northern and central Alberta, Canada, between 1995 and 1997. Multivariate logistic regression was used to control for maternal alcohol consumption, drug dependence, maternal age, maternal weight, prior intrauterine growth restriction and other confounders., Results: Maternal smoking was associated with a significantly reduced overall risk of preeclampsia (adjusted odds ratio [aOR]: .61; 95% confidence interval [CI]: .50-.75; P < .01). Stratified analyses showed that in primiparous pregnancies, maternal smoking was associated with a significantly decreased risk (aOR: .63; 95% CI: .50-.80; P < .01); in multiparous women, maternal smoking was not associated with a statistically significant decreased risk of preeclampsia (aOR: 0.72; 95% CI: .51-1.02; P > .05)., Conclusion: Maternal smoking is protective against preeclampsia. Understanding the underlying biologic mechanisms of this protective effect may advance our knowledge of the pathogenesis of preeclampsia.

Objective: Although there is general agreement that conception should be avoided when Crohn's disease is active, many questions remain unanswered for the woman with Crohn's disease in remission who becomes pregnant., Methods: Sixty-five charts of women with Crohn's disease quiescent at the start of pregnancy were identified between January 1993 and December 1997. Each pregnancy was matched to a healthy control pregnancy by date, age, parity, smoking status, and gestational age +/- 1 wk, and comparisons were carried out using matched analyses., Results: The two groups were similar in terms of maternal height, weight, and body mass index (BMI), in addition to the matched variables. The incidence of pregnancy complications was similar for most of the complications examined, whereas the incidence of poor maternal weight gain differed significantly between the groups (17/65 vs 2/65, p < 0.001). Flare-up of the Crohn's disease was seen in 13/65 (20%) of pregnancies. The greatest differences in neonatal outcomes were in terms of birth weight (3150+/-80 g vs 3500+/-60 g) and birth weight percentile (36.7%+/-.6% vs 57.5%+/-3.4%). Overall, there were 16 (24.6%) small for gestational age (SGA) births in the Crohn's group, compared with only one (1.5%) in the control group (p = 0.0007). Multivariate analysis was performed to identify factors predictive of SGA births in the Crohn's group. Ileal Crohn's disease was a statistically significant predictor (p = 0.035), whereas previous bowel resection trended toward statistical significance (p = 0.065)., Conclusions: In view of the risk of low birth weight, all women with Crohn's disease who become pregnant should be followed carefully during the pregnancy, particularly those who have ileal disease or who have previously undergone bowel resection. Furthermore, smoking cessation needs to be aggressively pursued in these patients.

Aim: To determine the correlation between gastric intramucosal pH and superior mesenteric artery (SMA) flow in newborn piglets., Methods: Fourteen newborn piglets were randomly assigned to either a control or to an epinephrine group which received 0,1,2,4,0 microg/kg/min of epinephrine for 60 minutes, each dose. Gastric tonometry was performed, SMA flow was measured, and intramucosal pH and the ratio of tonometer pCO(2) over arterial pCO(2) (rCO(2)) were calculated., Results: Intramucosal pH decreased over time in both groups, but tended to be lower in the epinephrine group. With increasing dose of epinephrine, SMA flow decreased; this in turn increased rCO(2) (p = 0.04) with a tendency to decrease intramucosal pH (p = 0.06)., Conclusions: Gastric tonometry may be useful in human neonates to evaluate gut ischaemia.

A case of fetal anasarca secondary to an intrapericardial teratoma is reported. The clinical, echocardiographic, and histologic features are described, along with a review of intrapericardial lesions.

A liposarcoma arose in the kidney of a 52-year-old man. After 13 years, it recurred, was resected, and recurred again. The second recurrence was inoperable.

(NZB x NZW)F1 mice initiated on fat restriction at weanling were significantly protected from the development of immune complex glomerulonephritis. Whereas the mice on high-fat intake demonstrated immune depositions both in capillary walls and mesangial areas in a diffuse granular pattern, those on a low-fat diet with caloric content similar to the high-fat diets exhibited mesangial confinement of the depositions of immunoglobulins, complement, and retroviral gp70. In association with these divergent patterns of immune deposition, the mice on high-fat diets had evidence of extensive diffuse cellular proliferation, wire loop lesion, and sclerosis in the glomeruli. In contrast, most of the mice on the low-fat diet showed only mesangial cell and matrix proliferations. In addition, the group of mice fed high saturated fat showed more severe glomerular pathology as compared to those fed high unsaturated fat. Paradoxically, levels of circulating immune complexes (as measured by the polyethylene glycol precipitation technique) in the high saturated fat group were low and did not correlate with the findings by light and immunofluorescence microscopy. These findings suggest that dietary fat restriction can serve as either a prophylactic or effective therapeutic approach to murine lupus nephritis.

Monoclonal antibody (MAb) to the mouse "helper" T cell antigen L3T4 inhibits the T cell response to class II major histocompatibility antigens on antigen-presenting cells in vitro and in thymectomized mice. To examine the effect of MAb to L3T4 on humoral immunity in euthymic mice, we treated BALB/c mice with 1 mg of anti-L3T4 i.p. at the time of immunization with either bovine serum albumin (BSA) or chicken egg ovalbumin (OA) in complete Freund's adjuvant. Administration of MAb to L3T4 selectively depleted greater than 90% of L3T4+ cells from the blood, spleen, and lymph nodes, but it had little effect on thymocytes. Mice treated with anti-L3T4 were unable to generate an IgG response to either BSA or OA. Treatment with anti-L3T4 also prevented the antigen-specific IgM response to these antigens, although it did not prevent nonspecific stimulation of IgM anti-BSA and anti-OA antibodies induced by adjuvant in the absence of antigen. Humoral immunity was inhibited even when treatment was delayed until 48 hr after immunization. These findings indicate that T cell help for humoral immunity can be abrogated in intact mice by MAb to L3T4.