Serum per- and polyfluoroalkyl substance concentrations and longitudinal change in post-infection and post-vaccination SARS-CoV-2 antibodies

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous throughout the United States. Previous studies have shown PFAS exposure to be associated with a reduced immune response. However, the relationship between serum PFAS and antibody levels following SARS-CoV-2 infection or COVID-19 vaccination has not been examined. We examined differences in peak immune response and the longitudinal decline of antibodies following SARS-CoV-2 infection and COVID-19 vaccination by serum PFAS levels in a cohort of essential workers in the United States. We measured serum antibodies using an in-house semi-quantitative enzyme-linked immunosorbent assay (ELISA). Two cohorts contributed blood samples following SARS-CoV-2 infection or COVID-19 vaccination. We used linear mixed regression models, adjusting for age, race/ethnicity, gender, presence of chronic conditions, location, and occupation, to estimate differences in immune response with respect to serum PFAS levels. Our study populations included 153 unvaccinated participants that contributed 316 blood draws over a 14-month period following infection, and 860 participants and 2451 blood draws over a 12-month period following vaccination. Higher perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA) concentrations were associated with a lower peak antibody response after infection (p = 0.009, 0.031, 0.015). Higher PFOS, perfluorooctanoic acid (PFOA), PFHxS, and PFNA concentrations were associated with slower declines in antibodies over time after infection (p = 0.003, 0.014, 0.026, 0.025). PFOA, PFOS, PFHxS, and PFNA serum concentrations prior to vaccination were not associated with differences in peak antibody response after vaccination or with differences in decline of antibodies over time after vaccination. These results suggest that elevated PFAS may impede potential immune response to SARS-CoV-2 infection by blunting peak antibody levels following infection; the same finding was not observed for immune response to vaccination.

A network meta-analysis of surgical treatments of complete rectal prolapse

PURPOSE

Surgical treatment of complete rectal prolapse can be undertaken via an abdominal or a perineal approach. The present network meta-analysis aimed to compare the outcomes of different abdominal and perineal procedures for rectal prolapse in terms of recurrence, complications, and improvement in fecal incontinence (FI).

METHODS

A PRISMA-compliant systematic review of PubMed, Scopus, and Web of Science was conducted. Randomized clinical trials comparing two or more procedures for the treatment of complete rectal prolapse were included. The risk of bias was assessed using the ROB-2 tool. The main outcomes were recurrence of full-thickness rectal prolapse, complications, operation time, and improvement in FI.

RESULTS

Nine randomized controlled trials with 728 patients were included. The follow-up ranged between 12 and 47 months. Posterior mesh rectopexy had significantly lower odds of recurrence than did the Altemeier procedure (logOR, - 12.75;  95% credible intervals, - 40.91, - 1.75), Delorme procedure (- 13.10; - 41.26, - 2.09), resection rectopexy (- 11.98; - 41.36, - 0.19), sponge rectopexy (- 13.19; - 42.87, - 0.54), and sutured rectopexy (- 13.12; - 42.58, - 1.50), but similar odds to ventral mesh rectopexy (- 12.09; - 41.7, 0.03). Differences among the procedures in complications, operation time, and improvement in FI were not significant.

CONCLUSIONS

Posterior mesh rectopexy ranked best with the lowest recurrence while perineal procedures ranked worst with the highest recurrence rates.

COVID-19 vaccination and changes in the menstrual cycle among vaccinated persons

OBJECTIVE

To describe the characteristics of people who experience changes to their menstrual cycle after COVID-19 vaccination.

DESIGN

Longitudinal study.

PATIENT(S)

We recruited a volunteer sample with and without a history of SARS-CoV-2 infection who enrolled in the Arizona COVID-19 Cohort (CoVHORT) study and participated in a reproductive sub-cohort who were pre-menopausal, not pregnant, and had received a COVID-19 vaccine in 2021 (n = 545).

EXPOSURE(S)

Demographic and reproductive characteristics were collected via self-reports.

MAIN OUTCOME MEASURE(S)

Information on self-reported changes in the menstrual cycle after COVID-19 vaccination was collected from May 2021 to December 2021. We looked at demographic and reproductive characteristics as predictors of menstrual cycle change.

RESULT(S)

The majority of our vaccinated sample received the Pfizer-BioNTech vaccine (58%), and were 26-35 years old (51%), non-Hispanic (84%), and White (88%). Approximately 25% of vaccinated participants reported a change in their menstrual cycle after vaccination; the majority reported changes after their second dose (56%) as compared with their first (18%) and third (14%) doses. The most commonly reported changes were irregular menstruation (43%), increased premenstrual symptoms (34%), increased menstrual pain or cramps (30%), and abnormally heavy or prolonged bleeding (31%). High self-reported perceived stress levels compared with low perceived stress (OR, 2.22; 95% CI 1.12-4.37) and greater body mass index (OR, 1.04; 95% CI 1.00-1.07) were associated with greater odds of experiencing the menstrual cycle changes after the vaccination. Participants having a history of SARS-CoV-2 infection were less likely to report changes in their menstrual cycle after vaccination compared with the participants with no history of SARS-CoV-2 infection (OR, 0.58; 95% CI 0.32-1.04).

CONCLUSION(S)

Among vaccinated participants, approximately 25% of them reported predominantly temporary changes in the menstrual cycle, however, we are unable to determine whether these changes are due to normal cycle variability. The COVID-19 vaccines are safe and effective for everyone, including pregnant people and people trying to conceive; hence, these findings should not discourage vaccination.

Risk Factors for Reinfection with SARS-CoV-2 Omicron Variant among Previously Infected Frontline Workers

In a cohort of essential workers in the United States previously infected with SARS-CoV-2, risk factors for reinfection included being unvaccinated, infrequent mask use, time since first infection, and being non-Hispanic Black. Protecting workers from reinfection requires a multipronged approach including up-to-date vaccination, mask use as recommended, and reduction in underlying health disparities.

Accessing medical care for infertility: a study of women in Mexico

Objective

To investigate barriers in accessing care for infertility in Mexico, because little is known about this issue for low and middle-income countries, which comprise 80% of the world's population.

Design

Cross-sectional analysis.

Setting

Mexcian Teachers' Cohort.

Patients

A total of 115,315 female public school teachers from 12 states in Mexico.

Interventions

None.

Main Outcome Measures

The participants were asked detailed questions about their demographics, lifestyle characteristics, access to the health care system, and infertility history via a self-reported questionnaire. Log-binomial models, adjusted a priori for potential confounding factors, were used to estimate the prevalence ratios (PRs) and 95% confidence intervals ( CIs) of accessing medical care for infertility among women reporting a history of infertility.

Results

A total of 19,580 (17%) participants reported a history of infertility. Of those who experienced infertility, 12,470 (63.7%) reported seeking medical care for infertility, among whom 8,467 (67.9%) reported undergoing fertility treatments. Among women who reported a history of infertility, women who taught in a rural school (PR, 0.95; 95% CI, 0.92-0.97), spoke an indigenous language (PR, 0.88; 95% CI, 0.84-0.92), or had less than a university degree (PR, 0.93; 95% CI, 0.90-0.97) were less likely to access medical care for fertility. Women who had ever had a mammogram (PR, 1.07; 95% CI, 1.05-1.10), had a pap smear in the past year (PR, 1.08; 95% CI, 1.06-1.10), or who had used private health care regularly or in times of illness were more likely to access medical care for fertility.

Conclusions

The usage of infertility care varied by demographic, lifestyle, and access characteristics, including speaking an indigenous language, teaching in a rural school, and having a private health care provider.

SARS-CoV-2 infection history and antibody response to three COVID-19 mRNA vaccine doses

BACKGROUND

Three doses of coronavirus disease 2019 (COVID-19) messenger RNA (mRNA) vaccines produce robust antibody responses, but data are limited among individuals previously infected with SARS-CoV-2. From a cohort of health care personnel (75.5%), first responders (4.6%), and other frontline workers (19.8%) in 6 US states, we longitudinally assessed antibody waning after dose-2, and response to dose-3, according to SARS-CoV-2 infection history.

METHODS

Participants submitted sera every three months, after SARS-CoV-2 infection, and after each COVID-19 vaccine dose. Sera were tested for antibodies and reported quantitatively as area under the serial dilution curve (AUC). Changes in the AUC values over time were compared as fold-changes using a linear mixed model.

RESULTS

Analysis included 388 participants who received dose-3 by November 2021. Three comparison groups: (1) vaccine only with no known prior SARS-CoV-2 infection (n = 224); (2) infection prior to dose-1 (n = 123); and (3) infection after dose 2 and before dose-3 (n = 41). The interval from dose 2 and dose 3 was approximately 8-months. After dose-3, antibody levels rose 2.5-fold (95%CI = 2.2-3.0) in group 2, and 2.9-fold (95%CI = 2.6-3.3) in group 1. Those infected within 90 days before dose-3 (and median 233 days (IQR = 213-246) after dose-2) did not increase significantly after dose-3.

CONCLUSIONS

A third dose of mRNA vaccine typically elicited a robust humoral immune response among those with primary vaccination regardless of SARS-CoV-2 infection >3 months prior to boosting. Those with infection < 3 months prior to boosting did not have a significant increase in antibody concentrations in response to a booster.

Association of mRNA Vaccination With Clinical and Virologic Features of COVID-19 Among US Essential and Frontline Workers

Importance

Data on the epidemiology of mild to moderately severe COVID-19 are needed to inform public health guidance.

Objective

To evaluate associations between 2 or 3 doses of mRNA COVID-19 vaccine and attenuation of symptoms and viral RNA load across SARS-CoV-2 viral lineages.

Design, Setting, and Participants

A prospective cohort study of essential and frontline workers in Arizona, Florida, Minnesota, Oregon, Texas, and Utah with COVID-19 infection confirmed by reverse transcriptase-polymerase chain reaction testing and lineage classified by whole genome sequencing of specimens self-collected weekly and at COVID-19 illness symptom onset. This analysis was conducted among 1199 participants with SARS-CoV-2 from December 14, 2020, to April 19, 2022, with follow-up until May 9, 2022, reported.

Exposures

SARS-CoV-2 lineage (origin strain, Delta variant, Omicron variant) and COVID-19 vaccination status.

Main Outcomes and Measures

Clinical outcomes included presence of symptoms, specific symptoms (including fever or chills), illness duration, and medical care seeking. Virologic outcomes included viral load by quantitative reverse transcriptase-polymerase chain reaction testing along with viral viability.

Results

Among 1199 participants with COVID-19 infection (714 [59.5%] women; median age, 41 years), 14.0% were infected with the origin strain, 24.0% with the Delta variant, and 62.0% with the Omicron variant. Participants vaccinated with the second vaccine dose 14 to 149 days before Delta infection were significantly less likely to be symptomatic compared with unvaccinated participants (21/27 [77.8%] vs 74/77 [96.1%]; OR, 0.13 [95% CI, 0-0.6]) and, when symptomatic, those vaccinated with the third dose 7 to 149 days before infection were significantly less likely to report fever or chills (5/13 [38.5%] vs 62/73 [84.9%]; OR, 0.07 [95% CI, 0.0-0.3]) and reported significantly fewer days of symptoms (10.2 vs 16.4; difference, -6.1 [95% CI, -11.8 to -0.4] days). Among those with Omicron infection, the risk of symptomatic infection did not differ significantly for the 2-dose vaccination status vs unvaccinated status and was significantly higher for the 3-dose recipients vs those who were unvaccinated (327/370 [88.4%] vs 85/107 [79.4%]; OR, 2.0 [95% CI, 1.1-3.5]). Among symptomatic Omicron infections, those vaccinated with the third dose 7 to 149 days before infection compared with those who were unvaccinated were significantly less likely to report fever or chills (160/311 [51.5%] vs 64/81 [79.0%]; OR, 0.25 [95% CI, 0.1-0.5]) or seek medical care (45/308 [14.6%] vs 20/81 [24.7%]; OR, 0.45 [95% CI, 0.2-0.9]). Participants with Delta and Omicron infections who received the second dose 14 to 149 days before infection had a significantly lower mean viral load compared with unvaccinated participants (3 vs 4.1 log10 copies/μL; difference, -1.0 [95% CI, -1.7 to -0.2] for Delta and 2.8 vs 3.5 log10 copies/μL, difference, -1.0 [95% CI, -1.7 to -0.3] for Omicron).

Conclusions and Relevance

In a cohort of US essential and frontline workers with SARS-CoV-2 infections, recent vaccination with 2 or 3 mRNA vaccine doses less than 150 days before infection with Delta or Omicron variants, compared with being unvaccinated, was associated with attenuated symptoms, duration of illness, medical care seeking, or viral load for some comparisons, although the precision and statistical significance of specific estimates varied.

Implementing Psychological First Aid for Healthcare Workers During the COVID-19 Pandemic: A Feasibility Study of the ICARE Model

Maintaining the resilience of healthcare workers (HCWs) during the protracted COVID-19 pandemic is critical as chronic stress is associated with burnout, inability to provide high-quality care, and decreased attentiveness to infection prevention protocols. Between May and July 2020, we implemented the ICARE model of psychological first aid (PFA) in a novel online (i.e., telehealth) format to address the psychological support needs of HCWs during the COVID-19 pandemic. We found that HCWs needed psychological support related to obtaining clear information about pandemic policies and guidelines, navigating new rules and responsibilities, and processing overwhelming and conflicting emotions. The HCWs in our program repeatedly expressed appreciation for the support we provided. Future directions include establishing online discussion forums, increasing opportunities for individual support, and training HCWs to provide peer support using PFA. This program has far-reaching potential benefit to HCWs and to society at large in the context of a pandemic.

Pediatric Research Observing Trends and Exposures in COVID-19 Timelines (PROTECT): Protocol for a Multisite Longitudinal Cohort Study

BACKGROUND

Assessing the real-world effectiveness of COVID-19 vaccines and understanding the incidence and severity of SARS-CoV-2 illness in children are essential to inform policy and guide health care professionals in advising parents and caregivers of children who test positive for SARS-CoV-2.

OBJECTIVE

This report describes the objectives and methods for conducting the Pediatric Research Observing Trends and Exposures in COVID-19 Timelines (PROTECT) study. PROTECT is a longitudinal prospective pediatric cohort study designed to estimate SARS-CoV-2 incidence and COVID-19 vaccine effectiveness (VE) against infection among children aged 6 months to 17 years, as well as differences in SARS-CoV-2 infection and vaccine response between children and adolescents.

METHODS

The PROTECT multisite network was initiated in July 2021, which aims to enroll approximately 2305 children across four US locations and collect data over a 2-year surveillance period. The enrollment target was based on prospective power calculations and accounts for expected attrition and nonresponse. Study sites recruit parents and legal guardians of age-eligible children participating in the existing Arizona Healthcare, Emergency Response, and Other Essential Workers Surveillance (HEROES)-Research on the Epidemiology of SARS-CoV-2 in Essential Response Personnel (RECOVER) network as well as from surrounding communities. Child demographics, medical history, COVID-19 exposure, vaccination history, and parents/legal guardians' knowledge and attitudes about COVID-19 are collected at baseline and throughout the study. Mid-turbinate nasal specimens are self-collected or collected by parents/legal guardians weekly, regardless of symptoms, for SARS-CoV-2 and influenza testing via reverse transcription-polymerase chain reaction (RT-PCR) assay, and the presence of COVID-like illness (CLI) is reported. Children who test positive for SARS-CoV-2 or influenza, or report CLI are monitored weekly by online surveys to report exposure and medical utilization until no longer ill. Children, with permission of their parents/legal guardians, may elect to contribute blood at enrollment, following SARS-CoV-2 infection, following COVID-19 vaccination, and at the end of the study period. PROTECT uses electronic medical record (EMR) linkages where available, and verifies COVID-19 and influenza vaccinations through EMR or state vaccine registries.

RESULTS

Data collection began in July 2021 and is expected to continue through the spring of 2023. As of April 13, 2022, 2371 children are enrolled in PROTECT. Enrollment is ongoing at all study sites.

CONCLUSIONS

As COVID-19 vaccine products are authorized for use in pediatric populations, PROTECT study data will provide real-world estimates of VE in preventing infection. In addition, this prospective cohort provides a unique opportunity to further understand SARS-CoV-2 incidence, clinical course, and key knowledge gaps that may inform public health.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR1-10.2196/37929.

A Rasch analysis assessing the reliability and validity of the Arizona CoVHORT COVID-19 vaccine questionnaire

Background

Despite the widespread availability of COVID-19 vaccines in the United States, many that have chosen not to be vaccinated have done so because of vaccine hesitancy. This highlights the need for tools that accurately capture the knowledge, attitudes, and beliefs towards COVID-19 vaccines, and provide steps toward improving vaccine acceptance.

Methods

Participants of the Arizona CoVHORT (COVID-19 Cohort) received a one-time, electronic based cross-sectional questionnaire intended to capture underlying motivations regarding vaccination, as well as hesitations that may prevent people from getting vaccinated. Rasch analysis was conducted among 4703 CoVHORT participants who had completed the vaccine questionnaire to assess questionnaire reliability and validity. Response categories were grouped to optimize scale functioning and to ensure independent probabilities of participant endorsement.

Results

A total of 4703 CoVHORT participants completed the questionnaire, of whom 68% were female, and who had a mean age of 48 years. Participants were primarily White (90%), highly educated (63% with a college degree or above, with most respondents (45%) having an income of more than $75,000 per annum. The results indicated the questionnaire has good reliability and construct validity for assessing attitudes and beliefs about the COVID-19 vaccines. In-fit mean-squares for included items ranged from 0.61 to 1.72 and outfit mean-squares ranged from 0.56 to 1.75, and correlation coefficients ranged from 0.25 to 0.75. The person-item map indicated normal distribution of logit scores measuring perceptions about COVID-19 vaccinations.

Conclusions

The CoVHORT vaccine questionnaire demonstrated satisfactory reliability and construct validity in assessing attitudes and beliefs about COVID-19 vaccines. Overall results provide a starting point for a reliable and valid tool to assess knowledge and perceptions about COVID-19 vaccination, ultimately providing public health professionals with an instrument to assess the factors that are associated with vaccine acceptance or hesitancy.

Elucidating symptoms of COVID-19 illness in the Arizona CoVHORT: a longitudinal cohort study

OBJECTIVE

To elucidate the symptoms of laboratory-confirmed COVID-19 cases as compared with laboratory-confirmed negative individuals and to the untested general population among all participants who reported symptoms within a large prospective cohort study.

SETTING AND DESIGN

This work was conducted within the framework of the Arizona CoVHORT, a longitudinal prospective cohort study conducted among Arizona residents.

PARTICIPANTS

Eligible participants were any individual living in Arizona and were recruited from across Arizona via COVID-19 case investigations, participation in testing studies and a postcard mailing effort.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome measure was a comparison of the type and frequency of symptoms between COVID-19-positive cases, tested but negative individuals and the general untested population who reported experiencing symptoms consistent with COVID-19.

RESULTS

Of the 1335 laboratory-confirmed COVID-19 cases, 180 (13.5%) reported having no symptoms. Of those that did report symptoms, the most commonly reported were fatigue (82.2%), headache (74.6%), aches, pains or sore muscles (66.3%), loss of taste or smell (62.8) and cough (61.9%). In adjusted logistic regression models, COVID-19-positive participants were more likely than negative participants to experience loss of taste and smell (OR 12.1; 95% CI 9.6 to 15.2), bone or nerve pain (OR 3.0; 95% CI 2.2 to 4.1), headache (OR 2.6; 95% CI 2.2 to 3.2), nausea (OR 2.4; 95% CI 1.9 to 3.1) or diarrhoea (OR 2.1; 95% CI 1.7 to 2.6). Fatigue (82.9) and headache (74.9) had the highest sensitivities among symptoms, while loss of taste or smell (87.2) and bone or nerve pain (92.9) had the high specificities among significant symptoms associated with COVID-19.

CONCLUSION

When comparing confirmed COVID-19 cases with either confirmed negative or untested participants, the pattern of symptoms that discriminates SARS-CoV-2 infection from those arising from other potential circulating pathogens may differ from general reports of symptoms among cases alone.

Design of the Arizona CoVHORT: A Population-Based COVID-19 Cohort

This study is a prospective, population-based cohort of individuals with a history of SARS-CoV-2 infection and those without past infection through multiple recruitment sources. The main study goal is to track health status over time, within the diverse populations of Arizona and to identify the long-term consequences of COVID-19 on health and well-being. A total of 2,881 study participants (16.2% with a confirmed SARS-CoV-2 infection) have been enrolled as of December 22, 2020, with a target enrollment of 10,000 participants and a planned follow-up of at least 2 years. This manuscript describes a scalable study design that utilizes a wide range of recruitment sources, leveraging electronic data collection to capture and link longitudinal participant data on the current and emerging issues associated with the COVID-19 pandemic. The cohort is built within a collaborative infrastructure that includes new and established partnerships with multiple stakeholders, including the state's public universities, local health departments, tribes, and tribal organizations. Challenges remain for ensuring recruitment of diverse participants and participant retention, although the electronic data management system and timing of participant contact can help to mitigate these problems.

Bioequivalence of two lansoprazole delayed release capsules 30 mg in healthy male volunteers under fasting, fed and fasting-applesauce conditions: a partial replicate crossover study design to estimate the pharmacokinetics of highly variable drugs

An open-label, 2-treatment, 3-sequence, 3-period, single-dose, partial replicate crossover studies under fasting (n=48), fed (n=60) and fasting-applesauce (n=48) (sprinkled on one table spoonful of applesauce) modalities were conducted in healthy adult male volunteers to evaluate bioequivalence between 2 formulations of lansoprazole delayed release capsules 30 mg. In all the 3 studies, as per randomization, either test or reference formulations were administered in a crossover manner with a required washout period of at least 7 days. Blood samples were collected adequately (0-24 h) to determine lansoprazole plasma concentrations using a validated LC-MS/MS analytical method. To characterize the pharmacokinetic parameters (Cmax, AUC0-t, AUC0-∞, Tmax, Kel and T1/2) of lansoprazole, non-compartmental analysis and ANOVA was applied on ln-transformed values. The bioequivalence was tested based on within-subject variability of the reference formulation. In fasting and fed studies (within-subject variability>30%) bioequivalence was evaluated with scaled average bioequivalence, hence for the pharmacokinetic parameters Cmax, AUC0-t and AUC0-∞, the 95% upper confidence bound for (μT-μR)2-θσ2 WR was ≤0, and the point estimates (test-to-reference ratio) were within the regulatory acceptance limit 80.00-125.00%. In fasting-applesauce study (within-subject variability<30%) bioequivalence was evaluated with average bioequivalence, the 90% CI of ln-transformed data of Cmax, AUC0-t and AUC0-∞ were within the regulatory acceptance limit 80.00-125.00%. Based on these aforesaid statistical inferences, it was concluded that the test formulation is bioequivalent to reference formulation.

Caspase-9 is activated in a cytochrome c-independent manner early during TNFalpha-induced apoptosis in murine cells

FL5.12 pro-B lymphoma cells utilize the mitochondrial pathway to apoptosis in response to tumor necrosis factor (TNF) receptor occupation, yet high levels of the Bcl-2 family antiapoptotic protein, Bcl-x(L), fail to protect these cells against TNF-receptor-activated death. Bcl-x(L) expression delays, but does not totally block, the release of mitochondrial cytochrome c (cyt c) in these cells in response to TNFalpha-induced apoptosis and caspase-9 is processed prior to mitochondrial cyt c release under these circumstances. Early processing of caspase-9 also occurred in Apaf-1 knockout murine fibroblasts in response to TNF-receptor occupation. A caspase-9-specific inhibitor was more effective in delaying the progression of apoptosis in the FL5.12 Bcl-x(L) cells than was an inhibitor specific to caspase-3. Furthermore, downregulation of caspase-9 levels by RNA interference resulted in partial protection of these cells against TNF-receptor-activated apoptosis, indicating that caspase-9 activation contributed to early amplification of the caspase cascade. Consistent with this, proteolytic processing of caspase-9 was observed prior to processing by caspase-3, suggesting that caspase-3 was not responsible for early caspase-9 activation. We show that murine caspase-9 is efficiently processed by active caspase-8 at SEPD, the motif at which caspase-9 autoprocesses following its recruitment to the apoptosome. Our results suggest that, in addition to processing procaspase-3 and the BH3 protein Bid, active caspase-8 can cleave and activate procaspase-9 in response to TNF receptor crosslinking in murine cells.

Massive lower gastrointestinal bleeding due to Dieulafoy lesion of colon

A 25-year-old man with massive lower gastrointestinal bleeding underwent emergency mesenteric angiography. An actively bleeding lesion was found in the cecum. Right hemicolectomy was performed. Histology revealed a Dieulafoy lesion of the cecum. This is an extremely rare lesion responsible for massive lower GI bleeding.

Small variant STEVOR antigen is uniquely located within Maurer's clefts in Plasmodium falciparum-infected red blood cells

Malaria parasite antigens encoded by multigene families are important factors in virulence and in disease pathology. In Plasmodium falciparum, the virulence factor PfEMP-1 is encoded by the var multigene family and is exposed at the infected erythrocyte surface. PfEMP-1 is clonally variant, allowing the parasite to evade host immunity. The recently identified P. falciparum stevor multigene family and its products also have the potential to be involved in similar important aspects of host-parasite interactions. Here, we show tightly regulated stage-specific transcription of stevor occurring over just a few hours of the asexual parasite life cycle. Only a subset of stevor genes are transcribed in parasite populations maintained in cultures and in single micromanipulated parasites. Antibodies against STEVOR recognize proteins of the expected size (approximately 37 kDa) and localize STEVOR in Maurer's clefts, unique membranous structures located in the cytoplasm of infected erythrocytes. The fact that the timing of stevor expression and the location of STEVOR are clearly distinct from those of other parasite variant antigens suggests that this gene family may have a novel role in P. falciparum biology.

The 235 kDa rhoptry protein of Plasmodium (yoelii) yoelii: function at the junction

All malaria parasites are obligate intracellular organisms that must clearly recognise and discriminate between different cells during their life cycle. Invasion into a cell is a multi-step event that is marked by initial attachment proceeding to irreversible junction formation and penetration. A 235 kDa rhoptry protein (Py235) in the rodent malaria, Plasmodium yoelii yoelii has been shown to be involved in red blood cell (rbc) binding and is involved in a new mechanism of clonal phenotypic variation that may be important in adaptation and immune evasion. Immunisation studies using Py235 have also revealed a role for this protein in the virulence phenotype seen with P. y. yoelii in laboratory mice. Interestingly, the genes that encode this protein are present as a multi-gene family. In this paper, we examine Py235 at the level of DNA, transcription and expression, discussing the role of this protein during invasion, in virulence and in immune evasion.

Distribution and characterisation of the 235 kDa rhoptry multigene family within the genomes of virulent and avirulent lines of Plasmodium yoelii

In the rodent malaria species, Plasmodium yoelii, a multi-gene family (Py235) encodes a 235 kDa rhoptry protein. This protein is believed to be involved in merozoite attachment and invasion of red blood cells. Only two members of Py235 have been sequenced so far. Using genomic DNA from the virulent P. yoelii YM line we have PCR amplified additional members of this gene family. These >8 kb full length clones have been cloned and sequenced. Based on differences within the tri-amino acid repeat structure at the C-terminal end of the Py235 protein, it has been possible to divide the multi-gene family into subtypes. The protein translations of five full-length genes (representing four different subtypes) were compared. While there was a high level of amino acid identity at the C-terminal end of these proteins, the N-terminal region revealed a great deal of sequence diversity. Critically, certain residues appeared to be conserved notably seven out of eight cysteines. Comparison of two full-length genes of a particular sub-type shows >99% amino acid identity at the protein level, implying that very closely related genes exist within the parasite genome. We have used this new sequence information to compare the distribution of Py235 in the virulent YM and avirulent 17X lines of P. yoelii. Our results indicate that while the overall distribution of Py235 genes is broadly conserved between the two lines, significant differences exist when individual subtypes are compared.

Alzheimer's disease cybrids replicate beta-amyloid abnormalities through cell death pathways

Alzheimer's disease (AD) is characterized by the deposition in brain of beta-amyloid (Abeta) peptides, elevated brain caspase-3, and systemic deficiency of cytochrome c oxidase. Although increased Abeta deposition can result from mutations in amyloid precursor protein or presenilin genes, the cause of increased Abeta deposition in sporadic AD is unknown. Cytoplasmic hybrid ("cybrid") cells made from mitochondrial DNA of nonfamilial AD subjects show antioxidant-reversible lowering of mitochondrial membrane potential (delta(gYm), secrete twice as much Abeta(1-40) and Abeta(1-42), have increased intracellular Abeta(1-40) (1.7-fold), and develop Congo red-positive Abeta deposits. Also elevated are cytoplasmic cytochrome c (threefold) and caspase-3 activity (twofold). Increased AD cybrid Abeta(1-40) secretion was normalized by inhibition of caspase-3 or secretase and reduced by treatment with the antioxidant S(-)pramipexole. Expression of AD mitochondrial genes in cybrid cells depresses cytochrome c oxidase activity and increases oxidative stress, which, in turn, lowers delta(psi)m. Under stress, cells with AD mitochondrial genes are more likely to activate cell death pathways, which drive caspase 3-mediated Abeta peptide secretion and may account for increased Abeta deposition in the AD brain. Therapeutic strategies for reducing neurodegeneration in sporadic AD can address restoration of delta(psi)m and reduction of elevated Abeta secretion.

Depletion of Raf-1 protooncogene by geldanamycin causes apoptosis in human luteinized granulosa cells

OBJECTIVE

To investigate the hypothesis that epidermal growth factor (EGF) signaling in luteinized granulosa cells works through Raf-1 and mitogen-activated protein (MAP) kinases and that depletion of Raf-1 by geldanamycin will inhibit the signaling pathway and cause apoptosis.

DESIGN

Laboratory study.

SETTING

University of Minnesota.

PATIENT(S)

Human luteinized granulosa cells from IVF patients.

INTERVENTION(S)

The cells were treated with vehicle (DMSO), 0.5 microM of geldanamycin, 10 ng/mL of EGF, and geldanamycin + EGF.

MAIN OUTCOME MEASURE(S)

Radiochemical MAP kinase assay, Western blotting, confocal microscopy, and flow cytometry.

RESULT(S)

Geldanamycin treatment depleted Raf-1 and lowered MAP kinase activity in luteinized granulosa cells. EGF treatment increased MAP kinase phosphorylation and translocation of the phosphorylated MAP kinase to the nucleus. Geldanamycin blocked this effect. Cleavage of caspase-3, the executioner protein in apoptosis, into an active 17 kD fragment was observed by Western blotting in geldanamycin-treated cells. Finally, by flow cytometry we observed significantly increased percentages of subdiploid apoptotic nuclei in geldanamycin-treated cells.

CONCLUSION(S)

In human luteinized granulosa cells, EGF works through Raf-1, and MAP kinase and depletion of Raf-1 by geldanamycin resulted in decreased MAP kinase activity, increased activated caspase-3, and, ultimately, apoptosis.

The management of ureteric calculi without extracorporeal shock-wave lithotripsy

BACKGROUND

Extracorporeal shock-wave lithotripsy (ESWL) is a relatively new technological adjunct in the treatment of renal calculi, but availability is limited.

AIM

The aim of this study was to assess the outcome of ureteroscopic procedures in a unit without on-site ESWL facility.

METHODS

A retrospective study of all cases of ureteric calculi presenting to this hospital during the period 1991 to 1997 was performed.

RESULTS

One hundred and thirty five patients with a mean age of 46.8 years were evaluated. Ninety-four (69.5%) had their stone successfully manipulated and/or extracted at ureteroscopy. Using strict criteria, 41 patients (30.5%) had failed ureteroscopies. Fourteen (10.4%) suffered complications related to their ureteroscopy, thirteen had their complications treated conservatively and three (2.3%) needed open procedures.

CONCLUSION

Ureteroscopy has a high success rate and low morbidity. We continue to advocate ureteroscopy in the initial management of ureteric calculi.

Mitochondria and caspases in induced apoptosis in human luteinized granulosa cells

Apoptosis occurs as a physiologic process in the ovarian life cycle. Staurosporine, a protein kinase inhibitor, is reported to induce apoptosis. Here, we hypothesize that staurosporine will induce apoptosis in human luteinized granulosa cells and that mitochondria and the caspase cascade participate in this process. Luteinized granulosa cells isolated from in vitro fertilization patients were treated with staurosporine. Microscopy revealed that staurosporine treatment resulted in cells exhibiting evidence of apoptosis, including cell detachment, loss of cell processes, membrane shrinkage, and formation of apoptotic bodies. In the staurosporine-treated cells, flow cytometry and confocal microscopy showed a decrease in the mitochondrial cardiolipin levels. Western analysis showed cleavage of caspase-9, an initiator caspase, of caspase-3, an executioner caspase, and of a caspase substrate, poly-(ADP-ribose)-polymerase (PARP) in staurosporine-treated cells. These data support our hypothesis and that this is the first demonstration of the involvement of mitochondria and of cleavage of caspases in human luteinized granulosa cell apoptosis. This may serve as a useful model to delineate the mechanism of apoptosis in the ovary, such as corpus luteum regression.

Aneurysms complicating pulmonary autograft procedure for aortic valve replacement

Aneurysm formation in the left ventricular outflow tract related to the proximal end of the pulmonary autograft after the Ross procedure was present in 2 patients. Both occurred late after operation and were associated with prolapse of a leaflet of the autograft and significant regurgitation. Both were repaired with no immediate complications. There was no evidence of infection at time of operation. The probable mechanisms underlying this complication and the possibilities of avoiding it are discussed.

Induction of apoptosis in luteinized granulosa cells by the MAP kinase kinase (MEK) inhibitor PD98059

Our objective is to test the hypothesis that inhibition of mitogen-activated protein (MAP) kinase kinase (MEK) with PD98059 in human luteinized granulosa cells will block epidermal growth (EGF)-stimulated MAP kinase activity and induce apoptosis. Luteinized granulosa cells from human in vitro fertilization aspirates were cultured and treated with the following: (1) vehicle; (2) PD98059; (3) EGF; (4) PD98059 + EGF. Treatment with PD98059 suppressed MAP kinase activity, inhibited MAP kinase phosphorylation by Western blot analysis, blocked nuclear translocation of phosphorylated MAP kinase by confocal microscopy, and increased percentages of subdiploid apoptotic nuclei by flow cytometry. Our data are the first evidence that a relationship may exist between the MAP kinase pathway and control of apoptosis in human luteinized granulosa cells. These results support the hypothesis that suppression of the MAP kinase pathway may lead to apoptosis in these cells.

Effects of single and multiple treatments with L-dihydroxyphenylalanine (L-DOPA) on dopamine receptor-G protein interactions and supersensitive immediate early gene responses in striata of rats after reserpine treatment or with unilateral nigrostriatal lesions

We studied effects of L-dihydroxyphenylalanine (L-DOPA) treatment in rats following reserpine treatment or unilateral 6-hydroxydopamine (6-OHDA) injections into medial forebrain bundle. Quantitative in situ hybridization for mRNA's coding for the zinc finger immediate early gene (IEG) zif/268 or Jun family IEG jun b revealed that single L-DOPA injections accentuated IEG expression 3- to 7-fold in the dopamine (DA)-depleted striatum. This increased IEG response did not derive from any alterations in DA receptor-G protein coupling, assayed by DA stimulation of 35S-guanosine-5' (gamma-thio) triphosphate (35S-GTP-gamma-S) binding to striatal sections. Reserpine treatment increased both basal and maximal striatal DA-stimulated 35S-GTP-gamma-S binding. The augmented IEG responses to single L-DOPA treatments involved dependency on both D1 and D2 receptors and acutely to N-methyl-D-aspartate (NMDA) channels. Repetitive L-DOPA treatments yielded persistently elevated (zif/268) or additionally up-regulated (jun b) IEG response in the denervated striatum and down-regulated IEG responses in the control striatum. Degraded L-DOPA responses and appearance of involuntary movements after chronic L-DOPA use in advanced Parkinson's disease may derive from these IEG changes.

Expression and localization of the retinoblastoma gene during radiation-induced apoptosis in neonatal rat kidney

An in vivo neonatal rat kidney model was used to study an association between expression and localization of the retinoblastoma tumor-suppressor gene (Rb), or its protein product (pRb), and localization of radiation-induced apoptosis. The rat kidney has two distinct zones of differentiation at birth-an outer nephrogenic zone, in which cells are undifferentiated and new nephrons are forming, and a differentiated zone internal to this zone that has essentially the adult kidney form. At 6 h after radiation (5 Gy), high levels of relatively synchronous apoptosis are induced in the nephrogenic zone, with little effect on the differentiated zone, and proliferation in the nephrogenic zone is almost totally inhibited by radiation treatment, again with little effect in the differentiated area. We have used our knowledge of this model to analyze control (sham-treated) and irradiated renal tissue for Rb mRNA transcript levels and localization (Northern blot and in situ hybridization (ISH)), pRb expression (Western blot and immunolocalization), apoptosis and mitosis (light and electron microscopy, and DNA gel electrophoresis for apoptosis), and cells in S-phase ([3H]thymidine uptake and autoradiography). Northern blots showed no detectable alteration in Rb transcript levels between control and irradiated tissues, whereas Western blots indicated increased expression of pRb in protein extracted from irradiated kidney compared with controls. ISH confirmed that Rb transcripts were not substantially altered in the nephrogenic and differentiated zones in control versus irradiated renal tissue. Immunolocalization of pRb demonstrated little effect in the differentiated zone, but in the nephrogenic zone pRb expression was increased, especially the S-shaped prenephrons, and was also found in many, but not all, apoptotic cells in this zone. The results link radiation-induced apoptosis and increased pRb expression in a zone of the neonatal kidney having a low level of cell differentiation.

Mitochondrial toxins in models of neurodegenerative diseases. II: Elevated zif268 transcription and independent temporal regulation of striatal D1 and D2 receptor mRNAs and D1 and D2 receptor-binding sites in C57BL/6 mice during MPTP treatment

Sporadic Parkinson's disease (PD) may arise from a defect in complex I of the mitochondrial electron transport chain (ETC), transmitted through mitochondrial DNA mutations. The N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of experimental PD is believed to arise from loss of complex I activity in dopamine (DA) neurons after accumulation of MPP+, a potent complex I inhibitor and the two electron monoamine oxidase B oxidation product of MPTP. Acute MPP+ infusion into striatum, possibly mimicking the in vivo situation after MPTP treatment, increases release of DA and production of hydroxyl radical (-OH). We treated C57BL/6 mice with MPTP and followed the expression of the immediate-early gene zif268 in striatum as a marker of DA synaptic activity, determined the pharmacology of its activation during MPTP toxicity, and assayed the time course of MPTP effects on striatal DA transporter (DAT), and D1 and D2 DA receptor-binding sites and their mRNAs. MPTP (24 mg/kg b.i.d. for 4 doses) increased striatal zif268 expression, with peak effects observed 24 h after starting MPTP. Increased striatal zif268 was dependent mainly on DA D1 and to a lesser extent on non-NMDA glutamate receptors and was not altered by inhibition of nitric oxide synthase (NOS). Our MPTP schedule resulted in a loss of about one-third of nigral DA neurons. We observed with [3H]mazindol autoradiography that loss of striatal DAT sites after starting MPTP was heterogenous and greatest in centromedial striatum, reached a maximum at 48 h and showed a slight recovery at 2 weeks. Striatal D1 and D2 receptor-binding sites (measured with [3H]SCH23390 and [3H]spiperone binding, respectively) and mRNA levels for D1 and D2 receptors (determined with quantitative in situ hybridization) were altered after MPTP treatment in temporally independent manners. MPTP toxicity to the nigrostriatal system likely induces substantial striatal DA release in vivo and stimulates transcription of at least one major IEG, zif268, in striatal neurons. Increased striatal zif268 expression after MPTP appears to derive mainly from DA released onto D1 receptors, not by a NO-dependent process which has been described in striatal neurons in vitro. The rapid loss of striatal DA terminals after MPTP treatment alters D1 and D2 receptor sites independently of changes in their mRNA levels. Increased D1 and D2 gene transcription in this model may depend on re-innervation by DA terminals of striatal neurons and likely is not related to the increased zif268 transcription observed after MPTP.

A technique for the culture of Barrett's oesophageal cells

Establishment of cells in tissue culture from Barrett's columnar epithelium has been difficult. The aim of this study was to develop a successful tissue culture method employing a serum-free medium for cultivation of Barrett's epithelial cells. Fragments of Barrett's mucosal tissue were explanted in a 3:1 mixture of Dulbecco's modification of Eagle's medium and Ham's F12, to initiate the outgrowth of epithelial cells. Subsequently, a commercial serum-free medium (formulated for the growth of keratinocytes) was used for the propagation of Barrett's oesophagus cells without fibroblast growth. Cells established in culture retained their epithelial morphology, stained positive for cytokeratin, and contained Alcian blue (pH 2.5) and periodic acid-Schiff reagent-positive/diastase-resistant vacuoles, confirming their origin from Barrett's epithelium. Electron microscopy showed tonofilaments, microvilli and desmosomes. Coating the surface of culture vessels was not required and four cell strains could be passaged up to 20 times with no fibroblast growth, in the keratinocyte serum-free medium.

Candidiasis in cancer patients

One hundred clinical specimens from hospitalized cancer patients were examined microscopically for evidence of yeast cells and cultured for Candida colonization. Candida cells were observed microscopically in both unstained and Gram-stained preparations and culture in 60% of specimens.

Pediatric tumors in north west Pakistan and Afghan refugees

All patients referred to the Institute of Radiotherapy and Nuclear Medicine in Peshawar (IRNUM) during 1990 to 1994 were analyzed. There were 1655 children with biopsy-proven cancers; 1290 were from the North West Frontier Province (NWFP), and the remaining 365 were Afghan refugees. Male children from the NWFP were 67% and females were 33%. Among Afghan children, 69% were males and 31% were females. Patients whose histopathologies were doubtful or not available were excluded from the study. The most common tumors in children in the NWFP were lymphoid leukemia, lymphoma, myeloid leukemia, Wilms tumor, tumors of the central nervous system (CNS), soft tissue sarcoma, bone tumors, retinoblastoma, neuroblastoma, and testicular tumors. Among Afghan children the most common cancers were lymphoma, lymphoid leukemia, myeloid leukemia, Wilms tumor, retinoblastoma, tumors of soft tissue, bone tumors, CNS tumors, testicular tumors, and neuroblastoma.

Cancer in north west Pakistan and Afghan refugees

The medical records of all patients attending the Institute of Radiotherapy and Nuclear Medicine (IRNUM), Peshawar during 1990 and to 1994 were analysed to determine the frequency of most common cancers. There were 13,359 adults with biopsy proven cancers of these 10,371 belonged to the North West Frontier province (NWFP) and remaining 2,988 were Afghan refugees. In NWFP there were 55% males and 45% females, while in Afghan refugees there were 59% males and 41% females. Patients whose histopathology was doubtful or not available were excluded from the study. The most common male tumours were skin, lymphoma, oral cancer, urinary bladder, lung, oesophagus, soft tissue, prostate, brain and myeloid leukemia. Among male Afghan refugees the most common cancers were oesophagus, skin, lymphoma, oral cancer, soft tissue, myeloid leukemia, stomach, urinary bladder, testis and colorectal cancer. Breast cancer was the most common cancer in women.

T- and T/natural killer-cell lymphomas of the salivary gland: a clinicopathologic, immunohistochemical and molecular study of six cases

Primary salivary gland lymphomas are almost always of B lineage, with most being represented by low grade B-cell lymphoma of mucosa-associated lymphoid tissue. This study characterizes the rare non-B-cell lymphomas of the salivary gland based on an analysis of six cases. All patients were men, with a mean age of 53.5 years. They presented with submandibular or parotid mass, which on histological examination showed extensive interstitial infiltration by small, medium-sized, or large lymphoid cells. There was prominent invasion and expansion of the ducts and acini in five cases. Angioinvasion was evident in two cases. Three cases were of T lineage and were CD56 negative; one of these cases expressed CD30. Three cases showed an immunophenotype of CD2+ CD3(f)- CD3(p)+ CD56+, consistent with T/natural killer (NK) cell lymphoma. In situ hybridization for Epstein-Barr virus (EBV)-encoded early nuclear RNA (EBER) showed positive reaction exclusively in the three CD56+ cases. Clonal T-cell populations were shown in two CD56-negative cases by polymerase chain reaction on paraffin sections using primers for the T-cell-receptor (TCR) gamma-chain gene, but not in the other four cases (the three CD56+ cases and one CD56- case). Four patients (two CD56+ and two CD56-) died within 3 years, and two were disease free at 4 and 1.5 years, respectively. This study shows that salivary gland T- or T/NK-cell lymphomas cannot be reliably distinguished from B-cell lymphomas on morphological grounds alone, because both can show prominent lymphoepithelial lesions. It appears that T/NK-cell lymphomas, which are often extranodal in localization and strongly associated with Epstein-Barr virus (EBV), show a predilection to involve the salivary glands as well.

Prevalence of streptococcal sorethroat in the school children of Dhaka

Beta Haemolytic Streptococcal (BHS) infections and their sequelae Rheumatic Fever (RF) and Glomerulonephritis (GN) have a world wide distribution and so pose an important health problem. Reports show that there is considerable variation in the number of isolations from different groups. Present study intended to find out the health status of the school children in relation to streptococcal throat infection, in Dhaka Cantonment. It was a cross sectional, observational study. During one year period total six hundred and one (601) children were examined from one school of Dhaka Cantonment. Prevalence of streptococcus was found to be 22% among the study population with highest rate (67%) for group-G among BHS positive cases. True streptococcal infection was found in 8.7% cases & 2.2% cases were true GABHS positive cases. GABHS was significantly higher in large size families. Females and children from lower socioeconomic group were at higher risk. Females and children of large families may require special attention regarding prevention of streptococcal infection and RF/RHD prevention programme.

The nonactivated estrogen receptor (naER) of the goat uterus is a tyrosine kinase

The nonactivated estrogen receptor (naER) has been isolated and purified to absolute homogeneity from the goat uterine cytosol. It is a 66-kDa protein, sedimenting at 4.2 S on linear sucrose density gradients and having a Stokes radius of 36 A. It displays high affinity and specificity for estradiol and diethyl stilbestrol with a Kd of 1 x 10(-10) M. CNBr peptide analysis reveals that it has a primary structure distinctly different from that of the regular estrogen receptor even though anti-ER antibody cross-reacts with the nonactivated ER. The protein gains access to the DNA only upon dimerization with the estrogen receptor activation factor (E-RAF), a DNA-binding protein having no capacity to bind estradiol. Analysis reveals that both naER and E-RAF are protein kinases. While the E-RAF is a serine kinase, naER functions as a tyrosine kinase. No protein kinase activity is displayed by the regular estrogen receptor. The protein kinase activity of the naER is inhibited in the presence of estradiol. Similarly, the protein kinase activities associated with the proteins disappear when the naER and E-RAF are brought together.

T-cell-rich B-cell lymphoma presenting as liver disease

We describe a series of eight cases of T-cell-rich B-cell lymphoma diagnosed on liver biopsy and collected over a period of 15 years. Of seven cases that were referred from elsewhere, in only one was the correct diagnosis of B-cell lymphoma suggested. Common errors included misdiagnosis as inflammatory disease on histology, and misinterpretation as T-cell lymphoma on immunohistochemistry. However, the cases had a distinct morphological appearance and immunohistochemical profile. They showed a lymphohistiocytic or granulomatous infiltrate, usually centred on portal tracts and containing abundant small T-cells and scanty B-cell blasts. All patients had an atypical clinical presentation which favoured non-neoplastic liver disease. In seven cases liver involvement represented Stage IV disease and in one case disease was confined to the liver consistent with a primary hepatic lymphoma. Despite combination chemotherapy, the prognosis was poor with no patients surviving beyond 15 months from diagnosis. We believe T-cell-rich B-cell lymphoma to be an under-recognized subset of non-Hodgkin's lymphoma that may mimic primary liver disease.

Ischaemic colitis: clinical, radiological and pathological correlation in three cases

The clinical and plain radiographic findings in three patients presenting with ischaemic colitis are presented. The radiographic signs were atypical in that featureless dilatation of the large bowel was present with no evidence of gas within the bowel wall or 'thumbprinting', and changes were not localized to the left colon. No thrombotic or embolic vascular occlusion was evident on examination of the resected specimens. We attempt to correlate the pathological and radiological findings, and emphasize the importance of considering this diagnosis in elderly patients who have a dilated featureless colon on plain radiographs.

Association of oral carcinoma with nasswar (snuff dipping)

A total of 186 cases of oral carcinoma were treated at the Institute of Radiotherapy and Nuclear Medicine (IRNUM), Peshawar, and at the District Headquarter Teaching Hospital, Abbottabad, during a two-year period. These patients were investigated for their personal habits and environmental factors. Use of nasswar was the most significant habit. We found that 91% of patients had the habit of nasswar dipping for more than 10 years. A history of tobacco smoking was noted in 44% of cases. Of these, 96% were also nasswar addicts. A significant correlation of the oral lesions was found with the site of the nasswar (snuff) dipping. We concluded that nasswar and other types of smokeless tobacco are not safe alternatives to tobacco smoking.

Localized amyloidosis of the lower genitourinary tract: a clinicopathological and immunohistochemical study of nine cases

A series of nine cases of localized amyloidosis of the lower genitourinary tract are reported. The patients comprised six males and three females with an age range of 50-79 years at initial presentation. Clinically and on cystoscopy, the lesions were often diagnosed as neoplasms. Histologically, seven cases had typical features of localized amyloid deposits, while two cases had an unusual appearance with a florid histiocytic and giant cell reaction. Using an immunoperoxidase staining method the deposits were non-reactive with antibodies to serum amyloid A protein, prealbumin and beta 2 microglobulin, while equivocal immunoreactivity was seen with anti-light chain antibodies.

Increased thermal stability of proteins in the presence of naturally occurring osmolytes

Organisms and cellular systems which have adapted to stresses such as high temperature, desiccation, and urea-concentrating environments have responded by concentrating particular organic solutes known as osmolytes. These osmolytes are believed to confer protection to enzyme and other macromolecular systems against such denaturing stresses. Differential scanning calorimetric (DSC) experiments were performed on ribonuclease A and hen egg white lysozyme in the presence of varying concentrations of the osmolytes glycine, sarcosine, N,N-dimethylglycine, and betaine. Solutions containing up to several molar concentrations of these solutes were found to result in considerable increases in the thermal unfolding transition temperature (Tm) for these proteins. DSC scans of ribonuclease A in the presence of up to 8.2 M sarcosine resulted in reversible two-state unfolding transitions with Tm increases of up to 22 degrees C and unfolding enthalpy changes which were independent of Tm. On the basis of the thermodynamic parameters observed, 8.2 M sarcosine results in a stabilization free energy increase of 7.2 kcal/mol for ribonuclease A at 65 degrees C. This translates into more than a 45,000-fold increase in stability of the native form of ribonuclease A over that in the absence of sarcosine at this temperature. Catalytic activity measurements in the presence of 4 M sarcosine give kcat and Km values that are largely unchanged from those in the absence of sarcosine. DSC of lysozyme unfolding in the presence of these osmolytes also results in Tm increases of up to 23 degrees C; however, significant irreversibly occurs with this protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential scanning calorimetry of bovine rhodopsin in rod-outer-segment disk membranes

Rhodopsin-containing retinal rod disk membranes from cattle have been examined by differential scanning calorimetry. Under conditions of 67 mM phosphate pH 7.0, unbleached rod outer segment disk membranes gave a single major endotherm with a temperature of denaturation (Tm) of 71.9 +/- 0.4 degrees C and a thermal unfolding calorimetric enthalpy change (delta Hcal) of 700 +/- 17 kJ/mol rhodopsin. Bleached rod outer segment disk membranes (membranes that had lost their absorbance at 498 nm after exposure to orange light) gave a single major endotherm with a Tm of 55.9 +/- 0.3 degrees C and a delta Hcal of 520 +/- 17 kJ/mol opsin. Neither bleached nor unbleached rod outer segment disk membranes gave endotherms upon thermal rescans. When thermal stability is examined over the pH range of 4-9, the major endotherms of both bleached and unbleached rod outer segment disk membranes were found to show maximum stability at pH 6.1. The observed delta Hcal values for bleached and unbleached rod outer segment disk membranes exhibit membrane concentration dependences which plateau at protein concentrations beyond 1.5 mg/mL. For partially bleached samples of rod outer segment disk membranes, the calorimetric enthalpy change for opsin appears to be somewhat dependent on the degree of bleaching, indicating intramembrane nearest neighbor interactions which affect the unfolding of opsin. Delta Hcal and Tm are particularly useful for assessing stability and testing for completeness of regeneration of rhodopsin from opsin. Other factors such as sample preparation and the presence of low concentrations of ethanol also affect the delta Hcal values while the Tm values remain fairly constant. This shows that the delta Hcal is a sensitive parameter for monitoring environmental changes of rhodopsin and opsin.

Invasive aspergillosis in immunosuppressed patients: potential hazard of hospital building work

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