A broad assessment of covid-19 vaccine safety using tree-based data-mining in the vaccine safety datalink

BACKGROUND

Except for spontaneous reporting systems, vaccine safety monitoring generally involves pre-specifying health outcomes and post-vaccination risk windows of concern. Instead, we used tree-based data-mining to look more broadly for possible adverse events after Pfizer-BioNTech, Moderna, and Janssen COVID-19 vaccination.

METHODS

Vaccine Safety Datalink enrollees receiving ≥1 dose of COVID-19 vaccine in 2020-2021 were followed for 70 days after Pfizer-BioNTech or Moderna and 56 days after Janssen vaccination. Incident diagnoses in inpatient or emergency department settings were analyzed for clustering within both the hierarchical ICD-10-CM code structure and the post-vaccination follow-up period. We used the self-controlled tree-temporal scan statistic and TreeScan software. Monte Carlo simulation was used to estimate p-values; p = 0.01 was the pre-specified cut-off for statistical significance of a cluster.

RESULTS

There were 4.1, 2.6, and 0.4 million Pfizer-BioNTech, Moderna, and Janssen vaccinees, respectively. Clusters after Pfizer-BioNTech vaccination included: (1) unspecified adverse effects, (2) common vaccine reactions, such as fever, myalgia, and headache, (3) myocarditis/pericarditis, and (4) less specific cardiac or respiratory symptoms, all with the strongest clusters generally after Dose 2; and (5) COVID-19/viral pneumonia/sepsis/respiratory failure in the first 3 weeks after Dose 1. Moderna results were similar but without a significant myocarditis/pericarditis cluster. Further investigation suggested the fifth signal group was a manifestation of mRNA vaccine effectiveness after the first 3 weeks. Janssen vaccinees had clusters of unspecified or common vaccine reactions, gait/mobility abnormalities, and muscle weakness. The latter two were deemed to have arisen from confounding related to practices at one site.

CONCLUSIONS

We detected post-vaccination clusters of unspecified adverse effects, common vaccine reactions, and, for the mRNA vaccines, chest pain and palpitations, as well as myocarditis/pericarditis after Pfizer-BioNTech Dose 2. Unique advantages of this data mining are its untargeted nature and its inherent adjustment for the multiplicity of diagnoses and risk intervals scanned.

A safety study evaluating non-COVID-19 mortality risk following COVID-19 vaccination

BACKGROUND

The safety of COVID-19 vaccines plays an important role in addressing vaccine hesitancy. We conducted a large cohort study to evaluate the risk of non-COVID-19 mortality after COVID-19 vaccination while adjusting for confounders including individual-level demographics, clinical risk factors, health care utilization, and community-level socioeconomic risk factors.

METHODS

The retrospective cohort study consisted of members from seven Vaccine Safety Datalink sites from December 14, 2020 through August 31, 2021. We conducted three separate analyses for each of the three COVID-19 vaccines used in the US. Crude non-COVID-19 mortality rates were reported by vaccine type, age, sex, and race/ethnicity. The counting process model for survival analyses was used to analyze non-COVID-19 mortality where a new observation period began when the vaccination status changed upon receipt of the first dose and the second dose. We used calendar time as the basic time scale in survival analyses to implicitly adjust for season and other temporal trend factors. A propensity score approach was used to adjust for the potential imbalance in confounders between the vaccinated and comparison groups.

RESULTS

For each vaccine type and across age, sex, and race/ethnicity groups, crude non-COVID-19 mortality rates among COVID-19 vaccinees were lower than those among comparators. After adjusting for confounders with the propensity score approach, the adjusted hazard ratios (aHRs) were 0.46 (95% confidence interval [CI], 0.44-0.49) after dose 1 and 0.48 (95% CI, 0.46-0.50) after dose 2 of the BNT162b2 vaccine, 0.41 (95% CI, 0.39-0.44) after dose 1 and 0.38 (95% CI, 0.37-0.40) after dose 2 of the mRNA-1273 vaccine, and 0.55 (95% CI, 0.51-0.59) after receipt of Ad26.COV2.S.

CONCLUSION

While residual confounding bias remained after adjusting for several individual-level and community-level risk factors, no increased risk was found for non-COVID-19 mortality among recipients of three COVID-19 vaccines used in the US.

Tree-based data mining for safety assessment of first COVID-19 booster doses in the Vaccine Safety Datalink

BACKGROUND

The Centers for Disease Control and Prevention's Vaccine Safety Datalink (VSD) has been performing safety surveillance for COVID-19 vaccines since their earliest authorization in the United States. Complementing its real-time surveillance for pre-specified health outcomes using pre-specified risk intervals, the VSD conducts tree-based data-mining to look for clustering of a broad range of health outcomes after COVID-19 vaccination. This study's objective was to use this untargeted, hypothesis-generating approach to assess the safety of first booster doses of Pfizer-BioNTech (BNT162b2), Moderna (mRNA-1273), and Janssen (Ad26.COV2.S) COVID-19 vaccines.

METHODS

VSD enrollees receiving a first booster of COVID-19 vaccine through April 2, 2022 were followed for 56 days. Incident diagnoses in inpatient or emergency department settings were analyzed for clustering within both the hierarchical ICD-10-CM code structure and the follow-up period. The self-controlled tree-temporal scan statistic was used, conditioning on the total number of cases for each diagnosis. P-values were estimated by Monte Carlo simulation; p = 0.01 was pre-specified as the cut-off for statistical significance of clusters.

RESULTS

More than 2.4 and 1.8 million subjects received Pfizer-BioNTech and Moderna boosters after an mRNA primary series, respectively. Clusters of urticaria/allergy/rash were found during Days 10-15 after the Moderna booster (p = 0.0001). Other outcomes that clustered after mRNA boosters, mostly with p = 0.0001, included unspecified adverse effects, common vaccine-associated reactions like fever and myalgia, and COVID-19. COVID-19 clusters were in Days 1-10 after booster receipt, before boosters would have become effective. There were no noteworthy clusters after boosters following primary Janssen vaccination.

CONCLUSIONS

In this untargeted data-mining study of COVID-19 booster vaccination, a cluster of delayed-onset urticaria/allergy/rash was detected after the Moderna booster, as has been reported after Moderna vaccination previously. Other clusters after mRNA boosters were of unspecified or common adverse effects and COVID-19, the latter evidently reflecting immunity to COVID-19 after 10 days.

Health Care Utilization in the 6 Months Following SARS-CoV-2 Infection

IMPORTANCE

After SARS-CoV-2 infection, many patients present with persistent symptoms for at least 6 months, collectively termed post-COVID conditions (PCC). However, the impact of PCC on health care utilization has not been well described.

OBJECTIVES

To estimate COVID-19-associated excess health care utilization following acute SARS-CoV-2 infection and describe utilization for select PCCs among patients who had positive SARS-CoV-2 test results (including reverse transcription-polymerase chain reaction and antigen tests) compared with control patients whose results were negative.

DESIGN, SETTING, AND PARTICIPANTS

This matched retrospective cohort study included patients of all ages from 8 large integrated health care systems across the United States who completed a SARS-CoV-2 diagnostic test during March 1 to November 1, 2020. Patients were matched on age, sex, race and ethnicity, site, and date of SARS-CoV-2 test and were followed-up for 6 months. Data were analyzed from March 18, 2021, to June 8, 2022.

EXPOSURE

SARS-CoV-2 infection.

MAIN OUTCOMES AND MEASURES

Ratios of rate ratios (RRRs) for COVID-19-associated health care utilization were calculated with a difference-in-difference analysis using Poisson regression models. RRRs were estimated overall, by health care setting, by select population characteristics, and by 44 PCCs. COVID-19-associated excess health care utilization was estimated by health care setting.

RESULTS

The final matched cohort included 127 859 patients with test results positive for SARS-CoV-2 and 127 859 patients with test results negative for SARS-CoV-2. The mean (SD) age of the study population was 41.2 (18.6) years, 68 696 patients in each group (53.7%) were female, and each group included 66 211 Hispanic patients (51.8%), 9122 non-Hispanic Asian patients (7.1%), 7983 non-Hispanic Black patients (6.2%), and 34 326 non-Hispanic White patients (26.9%). Overall, SARS-CoV-2 infection was associated with a 4% increase in health care utilization over 6 months (RRR, 1.04 [95% CI, 1.03-1.05]), predominantly for virtual encounters (RRR, 1.14 [95% CI, 1.12-1.16]), followed by emergency department visits (RRR, 1.08 [95% CI, 1.04-1.12]). COVID-19-associated utilization for 18 PCCs remained elevated 6 months from the acute stage of infection, with the largest increase in COVID-19-associated utilization observed for infectious disease sequelae (RRR, 86.00 [95% CI, 5.07-1458.33]), COVID-19 (RRR, 19.47 [95% CI, 10.47-36.22]), alopecia (RRR, 2.52 [95% CI, 2.17-2.92]), bronchitis (RRR, 1.85 [95% CI, 1.62-2.12]), pulmonary embolism or deep vein thrombosis (RRR, 1.74 [95% CI, 1.36-2.23]), and dyspnea (RRR, 1.73 [95% CI, 1.61-1.86]). In total, COVID-19-associated excess health care utilization amounted to an estimated 27 217 additional medical encounters over 6 months (212.9 [95% CI, 146.5-278.4] visits per 1000 patients).

CONCLUSIONS AND RELEVANCE

This cohort study documented an excess health care burden of PCC in the 6 months after the acute stage of infection. As health care systems evolve during a highly dynamic and ongoing global pandemic, these data provide valuable evidence to inform long-term strategic resource allocation for patients previously infected with SARS-CoV-2.

COVID-19 Vaccination and Non-COVID-19 Mortality Risk - Seven Integrated Health Care Organizations, United States, December 14, 2020-July 31, 2021

By September 21, 2021, an estimated 182 million persons in the United States were fully vaccinated against COVID-19.* Clinical trials indicate that Pfizer-BioNTech (BNT162b2), Moderna (mRNA-1273), and Janssen (Johnson & Johnson; Ad.26.COV2.S) vaccines are effective and generally well tolerated (1-3). However, daily vaccination rates have declined approximately 78% since April 13, 2021^†; vaccine safety concerns have contributed to vaccine hesitancy (4). A cohort study of 19,625 nursing home residents found that those who received an mRNA vaccine (Pfizer-BioNTech or Moderna) had lower all-cause mortality than did unvaccinated residents (5), but no studies comparing mortality rates within the general population of vaccinated and unvaccinated persons have been conducted. To assess mortality not associated with COVID-19 (non-COVID-19 mortality) after COVID-19 vaccination in a general population setting, a cohort study was conducted during December 2020-July 2021 among approximately 11 million persons enrolled in seven Vaccine Safety Datalink (VSD) sites.^§ After standardizing mortality rates by age and sex, this study found that COVID-19 vaccine recipients had lower non-COVID-19 mortality than did unvaccinated persons. After adjusting for demographic characteristics and VSD site, this study found that adjusted relative risk (aRR) of non-COVID-19 mortality for the Pfizer-BioNTech vaccine was 0.41 (95% confidence interval [CI] = 0.38-0.44) after dose 1 and 0.34 (95% CI = 0.33-0.36) after dose 2. The aRRs of non-COVID-19 mortality for the Moderna vaccine were 0.34 (95% CI = 0.32-0.37) after dose 1 and 0.31 (95% CI = 0.30-0.33) after dose 2. The aRR after receipt of the Janssen vaccine was 0.54 (95% CI = 0.49-0.59). There is no increased risk for mortality among COVID-19 vaccine recipients. This finding reinforces the safety profile of currently approved COVID-19 vaccines in the United States.

The ART of conversation: feasibility and acceptability of a pilot peer intervention to help transition complex HIV-positive people from hospital to community

OBJECTIVES

To pilot a peer-based intervention for people living with HIV who used substances, had challenges with antiretroviral adherence and would be discharged from hospital to community.

STUDY DESIGN

A community-based, quasi-experimental pilot intervention study designed to assess feasibility, acceptability and connection to a community-based HIV organisation.

SETTING

This study was conducted in Toronto, Canada, at Casey House (CH; hospital for people living with HIV) in collaboration with the AIDS Committee of Toronto (ACT; community-based HIV organisation).

PARTICIPANTS

People living with HIV who were CH inpatient between 1 April 2017 and 31 March 2018, struggled with antiretroviral adherence, actively used substances and would be discharged to community were eligible. Forty people met criteria, 19 were approached by an inpatient nurse and 17 consented. Average age was 48.8 years (SD=11.4), 58.8% were male and participants averaged 7.8 physical and mental health comorbidities (SD=3.1).

INTERVENTION

Titled 'The ART of Conversation', the three-pronged personalised intervention was developed through input from CH clients and ACT volunteers, all living with HIV. Intervention components were (a) predischarge goal-setting (adherence, substance use and self-identified goal) with the study nurse; (b) predischarge meeting with an HIV+ peer volunteer (PV) and (c) nine postdischarge phone calls between PV and participant, once per day for 3 days, then once per week for 6 weeks.

PRIMARY OUTCOMES

Feasibility was measured through proportion of eligible participants recruited and PV availability. Acceptability was assessed through participant interviews at three times (preintervention, post-intervention and 6 weeks follow-up) and through PV call logs. Client records determined connection to ACT within the study timeframe.

RESULTS

Twelve participants completed the intervention and nine connected with ACT. Predischarge goal-setting and PV meeting were both feasible and acceptable. Postdischarge phone calls were a challenge as half of completers missed at least one call.

CONCLUSIONS

Although predischarge goal-setting and PV meeting were feasible, methods to maintain connection following discharge require further investigation.

Evaluation of critical congenital heart defects screening using pulse oximetry in the neonatal intensive care unit

OBJECTIVE

To evaluate the implementation of early screening for critical congenital heart defects (CCHDs) in the neonatal intensive care unit (NICU) and potential exclusion of sub-populations from universal screening.

STUDY DESIGN

Prospective evaluation of CCHD screening at multiple time intervals was conducted in 21 NICUs across five states (n=4556 infants).

RESULTS

Of the 4120 infants with complete screens, 92% did not have prenatal CHD diagnosis or echocardiography before screening, 72% were not receiving oxygen at 24 to 48 h and 56% were born ⩾2500 g. Thirty-seven infants failed screening (0.9%); none with an unsuspected CCHD. False positive rates were low for infants not receiving oxygen (0.5%) and those screened after weaning (0.6%), yet higher among infants born at <28 weeks (3.8%). Unnecessary echocardiograms were minimal (0.2%).

CONCLUSION

Given the majority of NICU infants were ⩾2500 g, not on oxygen and not preidentified for CCHD, systematic screening at 24 to 48 h may be of benefit for early detection of CCHD with minimal burden.

A Blind, Numerical Benchmark Study on Supercritical Water Heat Transfer Experiments in a 7-Rod Bundle

Heat transfer in supercritical water reactors (SCWRs) shows a complex behavior, especially when the temperatures of the water are near the pseudocritical value. For example, a significant deterioration of heat transfer may occur, resulting in unacceptably high cladding temperatures. The underlying physics and thermodynamics behind this behavior are not well understood yet. To assist the worldwide development in SCWRs, it is therefore of paramount importance to assess the limits and capabilities of currently available models, despite the fact that most of these models were not meant to describe supercritical heat transfer (SCHT). For this reason, the Gen-IV International Forum initiated the present blind, numerical benchmark, primarily aiming to show the predictive ability of currently available models when applied to a real-life application with flow conditions that resemble those of an SCWR. This paper describes the outcomes of ten independent numerical investigations and their comparison with wall temperatures measured at different positions in a 7-rod bundle with spacer grids in a supercritical water test facility at JAEA. The wall temperatures were not known beforehand to guarantee the blindness of the study. A number of models have been used, ranging from a one-dimensional (1-D) analytical approach with heat transfer correlations to a RANS simulation with the SST turbulence model on a mesh consisting of 62 million cells. None of the numerical simulations accurately predicted the wall temperature for the test case in which deterioration of heat transfer occurred. Furthermore, the predictive capabilities of the subchannel analysis were found to be comparable to those of more laborious approaches. It has been concluded that predictions of SCHT in rod bundles with the help of currently available numerical tools and models should be treated with caution.

Signal detection of adverse events with imperfect confirmation rates in vaccine safety studies using self-controlled case series design

The Vaccine Safety Datalink project captures electronic health record data including vaccinations and medically attended adverse events on 8.8 million enrollees annually from participating managed care organizations in the United States. While the automated vaccination data are generally of high quality, a presumptive adverse event based on diagnosis codes in automated health care data may not be true (misclassification). Consequently, analyses using automated health care data can generate false positive results, where an association between the vaccine and outcome is incorrectly identified, as well as false negative findings, where a true association or signal is missed. We developed novel conditional Poisson regression models and fixed effects models that accommodate misclassification of adverse event outcome for self-controlled case series design. We conducted simulation studies to evaluate their performance in signal detection in vaccine safety hypotheses generating (screening) studies. We also reanalyzed four previously identified signals in a recent vaccine safety study using the newly proposed models. Our simulation studies demonstrated that (i) outcome misclassification resulted in both false positive and false negative signals in screening studies; (ii) the newly proposed models reduced both the rates of false positive and false negative signals. In reanalyses of four previously identified signals using the novel statistical models, the incidence rate ratio estimates and statistical significances were similar to those using conventional models and including only medical record review confirmed cases.

Trivalent inactivated influenza vaccine is not associated with sickle cell crises in children

BACKGROUND AND OBJECTIVES

Children with sickle cell disease are considered at high risk for complications from influenza infection and are recommended to receive annual influenza vaccination. However, data on the safety of influenza vaccination in children with sickle cell anemia are sparse.

METHODS

Using a retrospective cohort of children aged 6 months to 17 years in 8 managed care organizations that comprise the Vaccine Safety Datalink and who had a diagnosis of sickle cell anemia from 1999 to 2006, we conducted matched case-control and self-controlled case series studies to examine the association of trivalent inactivated influenza vaccination with hospitalization for sickle cell crisis in the 2 weeks after vaccination.

RESULTS

From an original pool of 1085 pediatric subjects with a diagnosis of sickle cell anemia, we identified 179 children with at least 1 sickle cell crisis during any influenza season (October 1-March 31). In the matched case-control study (matching on age category, gender, Vaccine Safety Datalink site, and season), the odds ratio of hospitalization for a crisis in vaccinated compared with unvaccinated children was not significant: 1.3 (95% confidence interval 0.8-2.2). In the self-controlled case series study of hospitalized cases, the incident rate ratio for hospitalization with sickle cell crisis in the 2 weeks after trivalent inactivated influenza vaccination was also not significant: 1.2 (95% confidence interval 0.75-1.95).

CONCLUSION

This large cohort study did not find an association of influenza vaccination and hospitalization for sickle cell crises in children with sickle cell anemia.

Impact of Maternal Influenza Vaccination During Pregnancy on the Incidence of Acute Respiratory Illness Visits Among Infants

OBJECTIVE

To determine whether influenza vaccination of pregnant women prevents visits for respiratory illness in their infants born during the influenza season.

DESIGN

Retrospective matched cohort study.

SETTING

Four managed care organizations in the United States. Patients A total of 41 129 infants (3160 and 37 969 born to vaccinated and unvaccinated mothers, respectively) born between 1995 and 2001. Main Exposure Maternal influenza vaccination. Infants were considered exposed if their gestational age at birth was at least 30 weeks, if the time from maternal vaccination to birth was at least 28 days, and if they were exposed to at least 14 days of the influenza season.

MAIN OUTCOME MEASURES

Incidence of acute respiratory illnesses (outpatient, emergency department, and inpatient settings combined) and incident rate ratios (IRRs) for infants exposed and unexposed to maternal vaccination during the following 4 periods: peak influenza, respiratory syncytial virus predominant, periseasonal, and summer weeks. The time to the first acute respiratory illness during peak influenza weeks was also assessed.

RESULTS

During the peak influenza weeks, infant visit rates were 15.4 and 17.1 per 100 person-months for exposed and unexposed infants, respectively (IRR, 0.90; 95% confidence interval, 0.80-1.02). Adjusted IRRs for the 4 periods found a protective effect of infant female sex, whereas Medicaid status and maternal high-risk status increased infant visit rates. Maternal influenza vaccination did not reduce visit rates during any of the 4 time periods (IRR for peak influenza season, 0.96; 95% confidence interval, 0.86-1.07) and did not delay the onset of first respiratory illness.

CONCLUSION

We were unable to demonstrate that maternal influenza vaccination reduces respiratory illness visit rates among their infants.

Safety of trivalent inactivated influenza vaccine in children 6 to 23 months old

CONTEXT

Beginning with the winter season of 2004-2005, influenza vaccination has been recommended for all children 6 to 23 months old in the United States. However, its safety in young children has not been adequately studied in large populations.

OBJECTIVE

To screen for medically attended events in the clinic, emergency department, or hospital after administration of trivalent inactivated influenza vaccine in children 6 to 23 months old.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort using self-control analysis, with chart review of significant medically attended events at 8 managed care organizations in the United States that comprise the Vaccine Safety Datalink. Participants were all children in the Vaccine Safety Datalink cohort 6 to 23 months old who received trivalent inactivated influenza vaccine between January 1, 1991, and May 31, 2003 (45,356 children with 69,359 vaccinations).

MAIN OUTCOME MEASURE

Any medically attended event significantly associated with trivalent inactivated influenza vaccine in risk windows 0 to 3 days, 1 to 14 days (primary analysis), 1 to 42 days, or 15 to 42 days after vaccination, compared with 2 control periods, one before vaccination and the second after the risk window. All individual ICD-9 codes as well as predefined aggregate codes were examined.

RESULTS

Before chart review, only 1 diagnosis, gastritis/duodenitis, was more likely to occur in the 14 days after trivalent inactivated influenza vaccine (matched odds ratio [OR], 5.50; 95% confidence interval [CI], 1.22-24.81 for control period 1, and matched OR, 4.33; 95% CI, 1.23-15.21 for control period 2). Thirteen medically attended events were less likely to occur after trivalent inactivated influenza vaccine, including acute upper respiratory tract infection, asthma, bronchiolitis, and otitis media. After chart review, gastritis/duodenitis was not significantly associated with trivalent inactivated influenza vaccine (matched OR, 4.00; 95% CI, 0.85-18.84 for control period 1; matched OR, 3.34; 95% CI, 0.92-12.11 for control period 2).

CONCLUSIONS

In the largest population-based study to date of the safety of trivalent inactivated influenza vaccine in young children, there were very few medically attended events, none of which were serious, significantly associated with the vaccine. This study provides additional evidence supporting the safety of universally immunizing all children 6 to 23 months old with influenza vaccine.

Effect of CME on primary care and OB/GYN treatment of breast masses

INTRODUCTION

CME program planners are being asked to move beyond assessments of knowledge to assessing the impact of CME on practice and patient outcomes.

METHODS

We conducted a pre-post analysis of administrative data from 107 physicians, nurse practitioners (NPs), or physician's assistants (PAs) who attended one or two continuing medical education (CME) programs (an in-person, mainly didactic session on breast complaints in women, or an individual mentorship with general surgeons) between August 2002 and March 2003. We examined associations between the number of trainings and attempted breast mass aspirations or general surgery referrals for breast masses; individual training and breast mass aspiration attempts or general surgery referrals; and provider type and attempted breast mass aspirations. Generalized linear mixed models were used to model dichotomous outcomes.

RESULTS

Clinicians who participated in individual trainings performed more breast mass aspirations after training (odds ratio (OR) 3.07, [95% confidence interval 1.10-8.54]). Participants who completed two trainings performed more breast mass aspirations after training (OR 2.33, [1.19-4.57]), while those who completed just one did not (OR 1.34, [0.39, 4.58]) but the effect started after the first training and did not strengthen after the second training. NPs and PAs attempted more aspirations after training (OR 6.1, [1.54, 24.1]), whereas physicians did not (OR 0.89 [0.36, 2.22]). Training was not associated with a change in referrals to general surgery. Referral appropriateness, pre-training readiness to change, and previous training in breast mass aspiration were not assessed.

DISCUSSION

Attempts to aspirate breast masses may increase after CME training. Individual training may be more effective than group training in increasing the likelihood of attempted aspirations.

Lung cancer and internal lung doses among plutonium workers at the Rocky Flats Plant: a case-control study

The authors conducted a nested case-control study of the association between lung cancer mortality and cumulative internal lung doses among a cohort of workers employed at the Rocky Flats Plant in Colorado from 1951 to 1989. Cases (n = 180) were individually matched with controls (n = 720) on age, sex, and birth year. Annual doses to the lung from plutonium, americium, and uranium isotopes were calculated for each worker with an internal dosimetry model. Lung cancer risk was elevated among workers with cumulative internal lung doses of more than 400 mSv in several different analytical models. The dose-response relation was not consistent at high doses. Restricting analysis to those employed for 15-25 years produced a statistically significant linear trend with dose (chi-square = 67.2, p < 0.001), suggesting a strong healthy worker survivor effect. The association between age at first internal lung dose and lung cancer mortality was statistically significant (odds ratio = 1.05, 95% confidence interval: 1.01, 1.10). No associations were found between lung cancer mortality and cumulative external penetrating radiation dose or cumulative exposures to asbestos, beryllium, hexavalent chromium, or nickel.

Ornithine decarboxylase and thymidine kinase activities and polyamine levels from selected organs of adult miniature swine receiving three concentrations of dietary menhaden oil

Mature, female swine were randomly assigned to one of seven dietary groups. Swine in groups 1-3 were fed a cholesterol-rich diet for 55 days while the remaining groups remained on a basal swine diet. At the end of the cholesterol(Chol)-preloading period the swine in groups 1-7 were placed on menhaden oil (MO) and/or corn oil (CO) as follows: groups 1 and 4, 15% CO (control); groups 2 and 5, 0.75% MO+14.25% CO; groups 3 and 7, 15% MO; and group 6, 7.5% MO+7.5% CO. Animals were killed at the end of the approximately 6-month feeding period and portions of liver, pancreas and colon mucosa were analyzed for both ornithine decarboxylase (ODC) and thymidine kinase (TK) activity while polyamine levels were measured in the liver and pancreas. Statistical analyses were carried out by one-way and two-way ANOVA and by trend analysis. In the pancreas, the highest MO group (group 7) had significantly higher ODC levels when compared with the CO control (group 4) and the next to highest MO group (group 6) (one-way ANOVA)-all non-cholesterol preloaded groups. Using a two-way ANOVA (Chol-by-MO), liver ODC was significantly lower in the CO control when compared with the lowest and highest MO groups (groups 5 and 7, respectively), again in the non-cholesterol-preloaded animals. In the colon, the swine in the Chol-low MO group (group 2) had significantly lower TK activity than the Chol/CO control group (group 1) and Chol/Hi MO group (group 3) (one-way ANOVA) and also had significantly lower activity than all groups except the CO control (group 4) (two-way ANOVA). Liver acetylputrescine in the lowest and highest MO groups (groups 5 and 7, respectively) was significantly higher than in the CO group (group 4). Liver spermidine in the Chol-Hi MO group (group 3) was significantly higher than the Chol-Lo MO group (group 2), while the highest MO group (group 7) had a statistically higher level than the other non-cholesterol groups (groups 4-6) (one-way ANOVA). Liver spermine was significantly higher in the Chol-Hi MO group (group 3) when compared to the CO control (group 1) and the Chol-Lo MO group (group 2) (one-way ANOVA). Pancreatic putrescine in the CO control (group 4) was significantly higher than all other groups (two-way ANOVA) while spermine from the 2 Chol-MO groups (groups 2 and 3) was higher than the Chol-CO control (group 1) (one-way ANOVA). Using trend analysis, liver TK, putrescine and spermidine increased in the non-cholesterol preloaded groups with increasing dietary MO, similar to the increase seen in ODC. Thus, of the three organs studied, only liver responded to menhaden oil with changes in both ODC itself or some of its metabolic engendered products and thymidine kinase; at least for one of the parameters, ODC, change associated with dietary MO was dependent on whether the swine were preloaded with cholesterol.

Effects of dietary fats on red blood cell membrane insulin receptor in normo- and hypercholesterolemic miniature swine

It has been demonstrated that the type of dietary fat affects insulin receptors in various tissues in normal humans and animals by altering membrane fluidity. This study compares the effects of n-3 fatty acids from fish oil and n-6 fatty acids from corn oil on red blood cell membrane insulin receptors in normal and hypercholesterolemic minipigs. A group of minipigs were made hypercholesterolemic by feeding cholesterol and lard for 2 months; the other group served as controls and was fed stock diet. Both groups were then fed experimental diets containing either corn oil or menhaden oil or a mixture of the two for 23 additional weeks. Blood was collected at 0, 2, 12 and 23 weeks after the start of the experimental diets and membranes were prepared from the red blood cells. Insulin binding to red blood cell membranes was measured by radioreceptor assay. Plasma insulin was measured by radioimmunoassay. Insulin binding to red blood cell membrane was compared with the fluidity of the membrane measured and reported earlier. There was no significant effect of cholesterol feeding on plasma insulin concentrations. After 23 weeks on experimental diet plasma insulin was significantly higher in minipigs fed menhaden oil compared to those fed corn oil. No such effect was observed in hypercholesterolemic minipigs. No significant effect of either hypercholesterolemia or fish oil was observed on red blood cell insulin binding. A significant negative relationship was observed between insulin binding and anisotropy at 4°C for all probes but at 37°C significant negative relationship was observed only with polar probes. The data suggest that n-3 fatty acids from fish oil significantly increases plasma insulin in minipigs compared to n-6 fatty acids from corn oil. However, the unsaturation has no significant effect on insulin receptors on erythrocytes. Similarly, prior hypercholesterolemic state also has no effect on plasma insulin levels or the insulin binding to red blood cell membranes.

Improving estimates of exposures for epidemiologic studies of plutonium workers

Epidemiologic studies of nuclear facilities usually focus on relations between cancer and doses from external penetrating radiation, and describe these exposures with little detail on measurement error and missing data. We demonstrate ways to document complex exposures to nuclear workers with data on external and internal exposures to ionizing radiation and toxic chemicals. We describe methods for assessing internal exposures to plutonium and external doses from neutrons; the use of a job exposure matrix for estimating chemical exposures; and methods for imputing missing data for exposures and doses. For plutonium workers at Rocky Flats, errors in estimating neutron doses resulted in underestimating the total external dose for production workers by about 16%. Estimates of systemic deposition do not correlate well with estimates of organ doses. Only a small percentage of workers had exposures to toxic chemicals, making epidemiologic assessments of risk difficult.

hprt mutant frequencies, nonpulmonary malignancies, and domestic radon exposure: "postmortem" analysis of an interesting hypothesis

The hypothesis that exposure to domestic radon raises the risk for leukemia and other nonpulmonary cancers has been proposed and tested in a number of epidemiologic studies over the past decade. During this period, interest in this hypothesis was heightened by evidence of increased frequencies of mutations at the hypoxanthine guanine phosphoribosyl transferase (hprt) gene in persons exposed to domestic radon (Bridges BA et al. [1991]: Lancet 337:1187-1189). An extension of this study (Cole J et al. [lsqb[1996]: Radiat Res 145:61-69) and two independent studies (Albering HJ et al. [1992[: Lancet 340:739; Albering HJ et al. [1994[: Lancet 344:750-751) found that hprt mutant frequency was not correlated with domestic radon exposure, and two well-designed epidemiologic studies showed no evidence of a relation between radon exposure and leukemia in children or adults. In this report, we present additional data from a study of Colorado high school students showing no correlation between domestic radon exposure and hprt mutant frequency. We use reanalyses of previous studies of radon and hprt mutant frequency to identify problems with this assay as a biomarker for domestic radon exposure and to illustrate difficulties in interpreting the statistical data. We also show with analyses of combined data sets that there is no support for the hypothesis that domestic radon exposure elevates hprt mutant frequency. Taken together, the scientific evidence provides a useful example of the problems associated with analyzing and interpreting data that link environmental exposures, biomarkers, and diseases in epidemiologic studies.

Petroleum jelly lipogranuloma of the penis treated with excision and native skin coverage

Penile augmentation by injection of petroleum jelly is still performed by nonmedical practitioners abroad and causes foreign body reactions with resultant scarring, deformity, and ulceration. Surgical treatment involves removal of the foreign material and granuloma, followed by scrotal flaps, inguinal flaps, free flaps, or split-thickness skin grafts. We present the use of native penile skin for coverage after resection of oleogranuloma in the first case of which we are aware. Local penile skin coverage allows for an excellent surgical result, with many potential advantages over flaps or skin grafts.

In vivo demonstration that human parathyroid hormone 1-38 inhibits the expression of osteoprotegerin in bone with the kinetics of an immediate early gene

Osteoprotegerin (OPG) is a potent inhibitor of osteoclast formation and function. To elucidate how OPG is regulated in bone, we examined (1) the expression and localization of OPG protein in bone tissue, (2) the effect of human parathyroid hormone 1-38 (hPTH 1-38) on OPG messenger RNA (mRNA) levels in rat femur metaphyseal and diaphyseal bone, and (3) the effect of hPTH(1-38) on expression of OPG mRNA in cultured osteoblast-like cells derived from the metaphysis and diaphysis, and in ROS 17/2.8 osteosarcoma cells. Because PTH has been shown to stimulate osteoblast activity via the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signal transduction pathway we also investigated whether PTH action on OPG in vivo is dependent on activation of cAMP/PKA pathway. Immunohistochemistry was used to evaluate OPG protein expression and Northern blot hybridization was used to analyze OPG mRNA expression both in vivo and in vitro. Immunohistochemistry of OPG protein expression in the rat distal femur metaphysis revealed that it was localized predominantly in preosteoblasts, osteoblasts, lining cells, and the osteoid layer, with occasional immunoreactivity in osteocytes and cells of the bone marrow. Subcutaneous (sc) administration of a single injection of hPTH(1-38) at 80 microg/kg induced a rapid and transient decrease in OPG mRNA expression in both metaphyseal and diaphyseal bone. The decrease in OPG message was evident by 1 h and mRNA levels returned to baseline after 3 h. PTH analog PTH(1-31), which stimulates intracellular cAMP accumulation, inhibited OPG expression, whereas PTH analogs (3-34 and 7-34) that do not stimulate cAMP production had no effect on expression. In contrast to PTH, prostaglandin E2 (PGE2) had no effect on OPG mRNA expression in vivo in the metaphyseal bone cells, under conditions in which PGE2 does promote expression of the c-fos gene. The in vivo effects of hPTH(1-38) on OPG mRNA were confirmed in isolated primary osteoblast cultures derived from either metaphyseal or diaphyseal bone as well as in ROS 17/2.8 osteosarcoma cells. We propose that the rapid and transient decrease in OPG expression may initiate a cascade of events resulting in the differentiation of osteoclast progenitor. Such a spatially and temporally programmed effect of PTH might contribute to bone turnover.

MABDOSE. I: Characterization of a general purpose dose estimation code

The MABDOSE software represents a general tool to perform internal radiation dosimetry. It uses a three-dimensional lattice in which to conduct radiation transport, scoring energy deposition in discrete voxels. The dosimetry system currently relies on the same algorithm used by the MIRD committee for photon transport, and assumes local deposition of particulate energy. A mathematical description of the dosimetry system's implementation is given. Additionally, a characterization of the system with respect to memory requirements, data libraries used, and simulation timing benchmarks, is presented. Validation of the software is presented in a companion manuscript.

MABDOSE. II: Validation of a general purpose dose estimation code

The MABDOSE software represents a general tool to assess internal radiation dose. A suite of tests are described that validate the dosimetry system's implementation.

METHODS

The validation suite is divided among tests that verify target digitalization, tumor digitalization and organ replacement, cumulated activity calculation, random number generation, radiation transport, and dose calculation.

RESULTS

A comparison between Reference Man organ volumes and MABDOSE organ volumes at (5 mm)3 resolution demonstrates volume correspondence within 10% save for ten organs having dimensions smaller than the target lattice resolution. An accounting of normal organ volume replaced by an arbitrary tumor volume indicates mass is conserved. A comparison between cumulated activities generated by MABDOSE and solutions obtained analytically demonstrates exact correspondence for curve-fitting algorithms. For mathematical modeling algorithms, cumulated activity solutions converge to their correct values provided sufficient data of high precision are input, accompanied by reasonable initial estimates of rate constants. A comparison of MABDOSE results with the MIRD 3 report demonstrates good agreement (<8% difference) in absorbed fractions for spheres at energies from 20 keV to 2.75 MeV. A comparison of MABDOSE results with the Cristy-Eckerman report demonstrates marginal agreement (specific absorbed fractions within a factor of 2 for all Reference Man organs) at simulation energies of 20, 50, and 100 keV. Lack of exact correspondence is attributed to volume digitalization errors, and to differences in cross-section libraries, interpolation schemes between cross-section data points, and random number generators. Finally, the doses reported by MABDOSE correspond to the correct algebraic combination of paired cumulated activities and "S" values.

CONCLUSIONS

The MABDOSE program has been validated as a general purpose computation tool for use in internal radionuclide dosimetry.

Determination of [35S]guanosine-5'-O-(3-thio)triphosphate binding mediated by cholinergic muscarinic receptors in membranes from Chinese hamster ovary cells and rat striatum using an anti-G protein scintillation proximity assay

An assay for measuring agonist-stimulated [35S]guanosine-5'-O-(3-thio)triphosphate (GTPgamma35S) binding to heterotrimeric GTP binding proteins was developed for use in 96-well format using commercially available anti-G protein antibodies captured by anti-IgG-coated scintillation proximity assay beads. Use of an anti-Galphaq/11 antibody to measure GTPgamma35S binding mediated by M1, M3, and M5 receptors stably expressed in Chinese hamster ovary (CHO) cells resulted in a marked increase in agonist-stimulated/basal binding ratio compared with whole membrane binding. Pertussis toxin (PTX) treatment of CHO M1 cells before membrane preparation resulted in a marked reduction in agonist-stimulated GTPgamma35S binding to whole membranes. Direct coupling of M1 receptors in CHO cells to inhibitory G proteins was demonstrated using an anti-Galphai(1-3) antibody, and this binding was inhibited by 76% following PTX treatment. However, PTX had no effect on M1-mediated binding determined using anti-Galphaq/11. CHO M2 receptors mediated robust agonist-stimulated GTPgamma35S binding measured with anti-Galphai(1-3), but coupled only weakly to Galphaq/11. Using membranes from rat striatum, GTPgamma35S binding stimulated by oxotremorine M was demonstrated using anti-Galphaq/11, anti-Galphai(1-3), and anti-Galphao antibodies. Agonist-stimulated binding to striatal membranes showed a marked antibody-dependent GDP requirement with robust signals obtained using 0.1 microM GDP for anti-Galphaq/11 compared with 50 microM GDP for anti-Galphai(1-3) and anti-Galphao. The potencies observed for pirenzepine and AFDX 116 blockade of agonist-stimulated GTPgamma35S binding to striatal membranes determined with anti-Galphaq/11 and anti-Galphao suggested mediation of these responses primarily by M1 and M4 receptors, respectively. Antibody capture GTPgamma35S binding using scintillation proximity assay technology provides a convenient, productive alternative to immunoprecipitation for exploration of receptor-G protein interaction in cells and tissues.

Dietary menhaden and corn oils and the red blood cell membrane lipid composition and fluidity in hyper- and normocholesterolemic miniature swine

Fatty acids in the diet are readily incorporated into lipids in various tissues. However, it is not clear whether all tissues have the same level of incorporation. Second, (n-6) unsaturated fatty acids increase the fluidity of membranes, but this has not been shown for (n-3) fatty acids. In this study, we measured the incorporation of (n-6) and (n-3) fatty acids into erythrocyte membrane lipids and studied their effects on the fluidity of erythrocyte membranes. One group of female miniature swine was made hypercholesterolemic by feeding the swine cholesterol and lard for 2 mo; the other group served as controls and was fed a stock diet. Both groups were then fed either corn oil or menhaden oil or a mixture of the two for 23 additional weeks. Blood was collected at 0, 2, 4, 12 and 23 wk after initialization of the experimental diets, and fatty acid composition of phospholipids was assessed. Membrane phospholipids of pigs fed menhaden oil had elevated (n-3) fatty acids (20:5 and 22:6), and lower 18:2 than those fed corn oil. There was no difference in 20:4 content. The fatty acid changes occurred as early as 2 wk after consumption of the corn oil or menhaden oil in pigs previously fed a stock diet, but it took longer in pigs previously fed lard + cholesterol, indicating residual effects of pretreatment. Menhaden oil increased anisotropy (indicating decreased fluidity) more than corn oil for the nonpolar probe diphenylhexatriene (DPH) at earlier time points, but not at 23 wk. Erythrocyte membrane fluidity was significantly related to membrane polyunsaturate content, with (n-6) fatty acids having a greater influence than (n-3) fatty acids. A comparison of the present red blood cell fatty acid compositions with brain synaptosome fatty acid compositions for the same animals showed poor correlations for some of the fatty acids. There was no significant direct relationship between docosahexaenoate (DHA) concentrations in erythrocyte membranes with DHA concentrations in brain synaptosomes from cerebellum, forebrain and caudate nucleus.

Zyme, a novel and potentially amyloidogenic enzyme cDNA isolated from Alzheimer's disease brain

The deposition of the beta amyloid peptide in neuritic plaques and cerebral blood vessels is a hallmark of Alzheimer's disease (AD) pathology. The major component of the amyloid deposit is a 4.2-kDa polypeptide termed amyloid beta-protein of 39-43 residues, which is derived from processing of a larger amyloid precursor protein (APP). It is hypothesized that a chymotrypsin-like enzyme is involved in the processing of APP. We have discovered a new serine protease from the AD brain by polymerase chain reaction amplification of DNA sequences representing active site homologous regions of chymotrypsin-like enzymes. A cDNA clone was identified as one out of one million that encodes Zyme, a serine protease. Messenger RNA encoding Zyme can be detected in some mammalian species but not in mice, rats, or hamster. Zyme is expressed predominantly in brain, kidney, and salivary gland. Zyme mRNA cannot be detected in fetal brain but is seen in adult brain. The Zyme gene maps to chromosome 19q13.3, a region which shows genetic linkage with late onset familial Alzheimer's disease. When Zyme cDNA is co-expressed with the APP cDNA in 293 (human embryonic kidney) cells, amyloidogenic fragments are detected using C-terminal antibody to APP. These co-transfected cells release an abundance of truncated amyloid beta-protein peptide and shows a reduction of residues 17-42 of Abeta (P3) peptide. Zyme is immunolocalized to perivascular cells in monkey cortex and the AD brain. In addition, Zyme is localized to microglial cells in our AD brain sample. The amyloidogenic potential and localization in brain may indicate a role for this protease in amyloid precursor processing and AD.

Clusterin (Apo J) protects against in vitro amyloid-beta (1-40) neurotoxicity

Clusterin is a secreted glycoprotein that is markedly induced in many disease states and after tissue injury. In the CNS, clusterin expression is elevated in neuropathological conditions such as Alzheimer's disease (AD), where it is found associated with amyloid-beta (A beta) plaques. Clusterin also coprecipitates with A beta from CSF, suggesting a physiological interaction with A beta. Given this interaction with A beta, the goal of this study was to determine whether clusterin could modulate A beta neurotoxicity. A mammalian recombinant source of human clusterin was obtained by stable transfection of hamster kidney fibroblasts with pADHC-9, a full-length human cDNA clone for clusterin. Recombinant clusterin obtained from this cell line, as well as a commercial source of native clusterin purified from serum, afforded dose-dependent neuroprotection against A beta (1-40) when tested in primary rat mixed hippocampal cultures. Clusterin afforded substoichiometric neuroprotection against several lots of A beta (1-40) but not against H2O2 or kainic acid excitotoxicity. These results suggest that the elevated expression of clusterin found in AD brain may have effects on subsequent amyloid-beta plaque pathology.

Human liposarcoma cell line, SW872, secretes cholesteryl ester transfer protein in response to cholesterol

Cholesteryl ester transfer protein (CETP) mediates the exchange of phospholipids and neutral lipids between the plasma lipoproteins, and plays an important role in high density lipoprotein (HDL) metabolism. While there are reports of low-level CETP secretion from cultured cells, the lack of a good model cell line has hampered the detailed study of CETP regulation and secretion. In this study, we have found that the human liposarcoma cell line, SW872, secretes cholesteryl ester transfer protein at levels substantially higher than observed from other cell lines. The secretion of CETP from this adipose-derived cell was up-regulated by 25-OH cholesterol and by low density lipoprotein (LDL) cholesterol in a concentration-dependent manner. Analysis of both full length and exon 9-deleted CETP mRNA demonstrated increases in response to LDL and 25-OH cholesterol, providing evidence for regulation at the message level. Our results suggest that the CETP-producing SW872 cell line may provide a model in which to study the regulation of this important modulator of lipoprotein metabolism.

Antitumor sulfonylurea-inhibited NADH oxidase of cultured HeLa cells shed into media

Conditioned culture media of HeLa S cells contain a soluble NADH oxidase activity inhibited by the antitumor sulfonylurea, N-(4-methylphenylsulfonyl)-N' -(4-chlorophenyl)urea (LY181984) similar to that associated with the outer surface of the plasma membrane. This activity was absent from media in which cells had not been grown and was present in conditioned culture media from which cells had been removed by centrifugation both for serum-containing and serum-free media. The Km with respect to NADH and response to thiol reagents were similar to those of the corresponding activity of the plasma membrane of HeLa cells. The conditioned HeLa culture media bound [3H]LY181984 with high affinity. Both antitumor sulfonylurea-inhibited and -resistant forms of the NADH oxidase were isolated by free-flow electrophoresis. The antitumor sulfonylurea-inhibited activity was purified to apparent homogeneity and was identified with a 33.5 kDa protein with an isoelectric point of about pH 4.5. The 33.5 kDa protein from conditioned HeLa culture medium both bound [3H]LY181984 and retained an LY181984-inhibited NADH oxidase activity. A polyclonal antisera was raised in rabbits to the purified 33.5 kDa constituent from conditioned HeLa culture medium. The antisera blocked the activity of the LY181984-inhibited NADH oxidase activity, immunoprecipitated the activity and reacted with a 33.5 kDa protein on Western blots while preimmune sera did not. Also inhibited and immunoprecipitated was NADH oxidase activity from HeLa plasma membranes. The findings are consistent with the 33.5 kDa drug-inhibited NADH oxidase activity of the culture media being a shed form of the corresponding native 34 kDa antitumor sulfonylurea-inhibited NADH oxidase activity of the HeLa cell plasma membrane.

Adhesion or anti-adhesion in cancer: what matters more?

The regulation of adhesion processes between normal epithelial cells is an essential condition for the maintenance of appropriate tissular architecture and differentiation. Quantitative and qualitative alterations in these homotypic adhesions occur during the transformation of normal into malignant epithelium. How these complex alterations in various homotypic adhesions modify the ability of tumor cells to detach from the original neoplastic site, to grow and move as single or clumped cells, and to invade the stroma are current issues in tumor biology. This review contrasts tumor cell adhesion mediated by E-cadherin which is consistently decreased in carcinomas, with adhesion mediated by CD44 and CEA which are increased in the tumors. A model proposing to resolve the apparent paradox of simultaneous adhesion and anti-adhesion mediated by the same protein is proposed.

HeLa plasma membranes bind the antitumor sulfonylurea LY181984 with high affinity

Homogenates, total particulate and plasma membranes of cultured HeLa S cells bound the tritiated antitumor sulfonylurea [3H]LY181984 with high affinity (Kd of 20 to 50 nM). Highest affinity binding (Kd of 25 nM) was to purified plasma membrane. The number of binding sites, estimated to represent 30 to 35 pmol/mg protein, would represent a low abundance constituent representing about 1/1000 of the total plasma membrane proteins. When corrected for mitochondrial uptake, binding recoveries of about 80% were achieved. Of the recovered specific radioactivity bound, approximately 90% was associated with the total particulate fraction. Of this, nuclei- and plasma membrane-free total membranes bound little or no [3H]LY181984 with high affinity. The high-affinity binding was restricted primarily to the plasma membranes. All fractions exhibited varying degrees of lower affinity binding indicative of a heterogeneous array of components capable of binding [3H]LY181984 at high concentrations of LY181984. Enrichment of 5-fold over total homogenates of high-affinity binding compared favorably to a 6.7-fold enrichment of the plasma membrane marker enzyme 5'-nucleotidase determined in parallel. We conclude that plasma membranes of HeLa cells contain high-affinity binding sites of low abundance for the antitumor sulfonylurea LY181984 and that the high-affinity sites are associated predominantly with the plasma membrane.

Heart and liver fatty acid composition and vitamin E content in miniature swine fed diets containing corn and menhaden oils

Female miniature swine, 4-11 yr, were fed 15% fat diets containing n-3 and/or n-6 polyunsaturated fat for 6 months, at 1.95 g fat/kg body weight. Liver lipids from menhaden oil-fed minipigs were elevated in the n-3 fatty acids: 20:5, 22:5 and 22:6, but heart lipids only in 20:5 and 22:6. Liver cell plasma membrane was elevated in 20:5, 22:5 and 22:6 and lowered in the n-6 acids 18:2 and 20:4 in menhaden oil-fed animals, to a greater extent than in the total tissue lipids. Liver alpha-tocopherol tended to decrease upon feeding menhaden oil, but heart alpha-tocopherol concentrations were not affected.

Pseudohyperphosphataemia in patients with multiple myeloma

The phosphate concentrations were measured in 41 patients who had multiple myeloma with paraproteinaemia using four different methods to compare the incidence of pseudohyperphosphataemia. The direct acid/molybdate method produced the highest number of anomalous results. The erroneously high phosphate concentration was attributable to the presence of turbidity in the reaction mixture. No association was found between paraprotein type and occurrence of turbidity. The direct acid/molybdate method was unreliable in patients with serum paraproteins and should therefore not be used for the measurement of phosphate concentration in such patients.

Molecular cloning and expression of human Ca(2+)-sensitive cytosolic phospholipase A2

Phospholipases A2 (PLA2s) play a key role in inflammatory processes through production of precursors of eicosanoids and platelet-activating factor. Recently, we described the purification of a novel approximately 100-kDa cytosolic PLA2 (cPLA2) from human monoblast U937 cells that is activated by physiological (intracellular) concentrations of Ca2+ (Kramer, R. M., Roberts, E. F., Manetta, J., and Putnam, J. E. (1991) J. Biol. Chem. 266, 5268-5272). Here we report the isolation of the complementary DNA encoding human cPLA2 and confirm its identity by expression in bacteria and in hamster cells. The predicted 749-amino acid cPLA2 protein has no similarity to the well known secretory PLA2s, but contains a structural element homologous to the C2 region of protein kinase C. The molecular cloning of cPLA2 will allow further studies defining the structure, function, and regulation of this novel PLA2.

Cleavage of amyloid beta peptide during constitutive processing of its precursor

The amyloid beta peptide (A beta P) is a small fragment of the much larger, broadly distributed amyloid precursor protein (APP). Abundant A beta P deposition in the brains of patients with Alzheimer's disease suggests that altered APP processing may represent a key pathogenic event. Direct protein structural analyses showed that constitutive processing in human embryonic kidney 293 cells cleaves APP in the interior of the A beta P, thus preventing A beta P deposition. A deficiency of this processing event may ultimately prove to be the etiological event in Alzheimer's disease that gives rise to senile plaque formation.

Effects of propranolol on blood lipids and lipoproteins in myocardial infarction

The effects of propranolol on lipids and lipoproteins were investigated in survivors of a recent myocardial infarction who were enrolled in the double-blind Beta-Blocker Heart Attack Trial. Nonfasting serum samples were obtained in more than 2800 patients assigned randomly to either propranolol or placebo. The propranolol-treated group had high-density lipoprotein cholesterol levels 3-4 mg/dl less and triglyceride concentrations 30-40 mg/dl higher than the placebo group. These effects occurred in men and women in all age categories.

Bromocriptine therapy in oligozoospermic infertile men

A prospective, randomized double-blind study with crossover using bromocriptine and placebo was performed on a group of 17 infertile males with idiopathic oligozoospermia. Twelve patients completed the duration of this study of eight months by receiving 5 mg of bromocriptine per day for four months followed by four months of placebo or vice versa. Prior to treatment, the sperm count was 8.76 +/- 1.32 (10(6)/ml). The hormonal profile was performed prior to treatment and included estimation of prolactin, T3, T4, thyroid stimulating hormone (TSH), testosterone, follicle stimulating hormone (FSH), and plasma LH. Stimulation studies using LHRH and TRH were also performed. All hormonal estimations were within normal limits. Compared to placebo, bromocriptine had no significant effect on sperm analysis, or basic hormonal profile. The stimulation test with luteinizing hormone releasing hormone (LHRH) was unchanged except for the basic plasma testosterone, which increased. The prolactin decreased following the thyrotropin releasing hormone (TRH) stimulation. Two pregnancies were noted four to six weeks following the end of treatment. Bromocriptine did not seem to be more effective than placebo in the treatment of idiopathic oligozoospermia.