Baseline Factors Associated with Self-reported Disease Flares Following COVID-19 Vaccination among Adults with Systemic Rheumatic Disease: Results from the COVID-19 Global Rheumatology Alliance Vaccine Survey

OBJECTIVE

To examine the frequency of, and risk factors for, disease flare following COVID-19 vaccination in patients with systemic rheumatic disease (SRD).

METHODS

An international study was conducted from April 2 to August 16, 2021, using an online survey of 5619 adults with SRD for adverse events following COVID-19 vaccination, including flares of disease requiring a change in treatment. We examined risk factors identified a priori based on published associations with SRD activity and SARS-CoV-2 severity, including demographics, SRD type, comorbidities, vaccine type, cessation of immunosuppressive medications around vaccination, and history of reactions to non-COVID-19 vaccines, using multivariable logistic regression.

RESULTS

Flares requiring a change in treatment following COVID-19 vaccination were reported by 4.9% of patients. Compared with rheumatoid arthritis, certain SRD, including systemic lupus erythematosus (OR 1.51, 95%CI 1.03, 2.20), psoriatic arthritis (OR 1.95, 95%CI 1.20, 3.18), and polymyalgia rheumatica (OR 1.94, 95%CI 1.08, 2.48) were associated with higher odds of flare, while idiopathic inflammatory myopathies were associated with lower odds for flare (OR 0.54, 95%CI 0.31-0.96). The Oxford-AstraZeneca vaccine was associated with higher odds of flare relative to the Pfizer-BioNTech vaccine (OR 1.44, 95%CI 1.07, 1.95), as were a prior reaction to a non-COVID-19 vaccine (OR 2.50, 95%CI 1.76, 3.54) and female sex (OR 2.71, 95%CI 1.55, 4.72).

CONCLUSION

SRD flares requiring changes in treatment following COVID-19 vaccination were uncommon in this large international study. Several potential risk factors, as well as differences by disease type, warrant further examination in prospective cohorts.

Association of Deepwater Horizon Oil Spill Response and Cleanup Work With Risk of Developing Hypertension

IMPORTANCE

Exposure to hydrocarbons, fine particulate matter (PM2.5), and other chemicals from the April 20, 2010, Deepwater Horizon disaster may be associated with increased blood pressure and newly detected hypertension among oil spill response and cleanup workers.

OBJECTIVE

To determine whether participation in cleanup activities following the disaster was associated with increased risk of developing hypertension.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study was conducted via telephone interviews and in-person home exams. Participants were 6846 adults who had worked on the oil spill cleanup (workers) and 1505 others who had completed required safety training but did not do cleanup work (nonworkers). Eligible participants did not have diagnosed hypertension at the time of the oil spill. Statistical analyses were performed from June 2018 to December 2021.

EXPOSURES

Engagement in cleanup activities following the Deepwater Horizon oil spill disaster, job classes, quintiles of cumulative total hydrocarbons exposure level, potential exposure to burning or flaring oil, and estimated PM2.5 were examined.

MAIN OUTCOMES AND MEASURES

Systolic and diastolic blood pressure measurements were collected during home exams from 2011 to 2013 using automated oscillometric monitors. Newly detected hypertension was defined as antihypertensive medication use or elevated blood pressure since the spill. Log binomial regression was used to calculate prevalence ratios (PR) and 95% CIs for associations between cleanup exposures and hypertension. Multivariable linear regression was used to estimate exposure effects on continuous blood pressure levels.

RESULTS

Of 8351 participants included in this study, 6484 (77.6%) were male, 517 (6.2%) were Hispanic, 2859 (34.2%) were non-Hispanic Black, and 4418 (52.9%) were non-Hispanic White; the mean (SD) age was 41.9 (12.5) years at enrollment. Among workers, the prevalence of newly detected hypertension was elevated in all quintiles (Q) of cumulative total hydrocarbons above the first quintile (PR for Q3, 1.29 [95% CI, 1.13-1.46], PR for Q4, 1.25 [95% CI, 1.10-1.43], and PR for Q5, 1.31 [95% CI, 1.15-1.50]). Both exposure to burning and/or flaring oil and gas (PR, 1.16 [95% CI, 1.02-1.33]) and PM2.5 from burning (PR, 1.26 [95% CI, 0.89-1.71]) for the highest exposure category were associated with increased risk of newly detected hypertension, as were several types of oil spill work including cleanup on water (PR, 1.34 [95% CI, 1.08-1.66]) and response work (PR, 1.51 [95% CI, 1.20-1.90]).

CONCLUSIONS AND RELEVANCE

Oil spill exposures were associated with newly detected hypertension after the Deepwater Horizon disaster. These findings suggest that blood pressure screening should be considered for workers with occupational hydrocarbon exposures.

Deepwater Horizon oil spill exposures and neurobehavioral function in GuLF study participants

INTRODUCTION

The 2010 Deepwater Horizon (DWH) disaster exposed tens of thousands of oil spill response and cleanup (OSRC) workers to hydrocarbons and other hazardous chemicals. Some hydrocarbons, such as toluene and hexane, have been found to have acute adverse effects on the central nervous system in occupational settings. However, no studies have examined the association between oil spill exposures and neurobehavioral function.

METHODS

We used data from the Gulf Long-term Follow-up Study, a cohort of adults who worked on the DWH response and cleanup. Total hydrocarbon (THC) exposure attributed to oil spill cleanup work was estimated from a job-exposure matrix linking air measurement data to detailed cleanup work histories. Participants were also categorized into 6 job categories, or OSRC classes, based on their activity with the highest exposure. Neurobehavioral performance was assessed at a clinical exam 4-6 years after the spill. We used multivariable linear regression to evaluate relationships of ordinal THC levels and OSRC classes with 16 neurobehavioral outcomes.

RESULTS

We found limited evidence of associations between THC levels or OSRC classes and decreased neurobehavioral function, including attention, memory, and executive function. Workers exposed to ≥3 ppm THC scored significantly worse (difference_1.0-2.9ppm = -0.39, 95% confidence interval (CI) = -0.74, -0.04) than workers exposed to <0.30 ppm THC for the digit span forward count test. There was also a possible threshold effect above 1 ppm THC for symbol digit test total errors (difference_1.0-2.9ppm = -0.56 (95% CI = -1.13, -0.003), difference_≥3.0ppm = -0.55 (95% CI = -1.20, 0.10)). Associations appeared to be stronger in men than in women. A summary latency measure suggested an association between more highly exposed jobs (especially support of operations workers) and decreased neurobehavioral function.

CONCLUSION

OSRC-related exposures were associated with modest decreases in neurobehavioral function, especially attention, memory, and executive function.

Developing Large-Scale Research in Response to an Oil Spill Disaster: a Case Study

Research conducted in the wake of a disaster can provide information to help mitigate health consequences, support future recovery efforts, and improve resilience. However, a number of barriers have prevented time-sensitive research responses following previous disasters. Furthermore, large-scale disasters present their own special challenges due to the number of people exposed to disaster conditions, the number of groups engaged in disaster response, and the logistical challenges of rapidly planning and implementing a large study. In this case study, we illustrate the challenges in planning and conducting a large-scale post-disaster research study by drawing on our experience in establishing the Gulf Long-term Follow-up (GuLF) Study following the 2010 Deepwater Horizon disaster. We describe considerations in identifying at-risk populations and appropriate comparison groups, garnering support for the study from different stakeholders, obtaining timely scientific and ethics review, measuring and characterizing complex exposures, and addressing evolving community health concerns and unmet medical needs. We also describe the NIH Disaster Research Response (DR2) Program, which provides a suite of resources, including data collection tools, research protocols, institutional review board guidance, and training materials to enable the development and implementation of time-critical studies following disasters and public health emergencies. In describing our experiences related to the GuLF Study and the ongoing efforts through the NIH DR2 Program, we aim to help improve the timeliness, quality, and value of future disaster-related data collection and research studies.

Lung Function in Oil Spill Response Workers 1-3 Years After the Deepwater Horizon Disaster

BACKGROUND

Little is known about the effects of inhalation exposures on lung function among workers involved in the mitigation of oil spills. Our objective was to determine the relationship between oil spill response work and lung function 1-3 years after the Deepwater Horizon (DWH) disaster.

METHODS

We evaluated spirometry for 7,775 adults living in the Gulf states who either participated in DWH response efforts (workers) or received safety training but were not hired (nonworkers). At an enrollment interview, we collected detailed work histories including information on potential exposure to dispersants and burning oil/gas. We assessed forced expiratory volume in 1 second (FEV1; mL), forced vital capacity (FVC; mL), and the ratio (FEV1/FVC%) for differences by broad job classes and exposure to dispersants or burning oil/gas using multivariable linear and modified Poisson regression.

RESULTS

We found no differences between workers and nonworkers. Among workers, we observed a small decrement in FEV1 (Beta, -71 mL; 95% confidence interval [CI], -127 to -14) in decontamination workers compared with support workers. Workers with high potential exposure to burning oil/gas had reduced lung function compared with unexposed workers: FEV1 (Beta, -183 mL; 95% CI, -316 to -49) and FEV1/FVC (Beta, -1.93%; 95% CI, -3.50 to -0.36), and an elevated risk of having a FEV1/FVC in the lowest tertile (prevalence ratio, 1.38; 95% CI, 0.99 to 1.92).

CONCLUSIONS

While no differences in lung function were found between workers and nonworkers, lung function was reduced among decontamination workers and workers with high exposure to burning oil/gas compared with unexposed workers.

Deepwater Horizon oil spill exposures and nonfatal myocardial infarction in the GuLF STUDY

BACKGROUND

Workers involved in the response and clean-up of the 2010 Deepwater Horizon oil spill faced possible exposures to crude oil, burning oil, dispersants and other pollutants in addition to physical and emotional stress. These exposures may have increased risk of myocardial infarction (MI) among oil spill workers.

METHODS

Gulf Long-term Follow-up (GuLF) STUDY participants comprise individuals who either participated in the Deepwater Horizon response efforts or registered for safety training but were not hired. Oil spill-related exposures were assessed during enrollment interviews conducted in 2011-2013. We estimated risk ratios (RR) and 95% confidence intervals for the associations of clean-up work characteristics with self-reported nonfatal MI up to three years post-spill.

RESULTS

Among 31,109 participants without history of MI prior to the spill, 77% worked on the oil spill. There were 192 self-reported MI during the study period; 151 among workers. Among the full cohort, working on the oil spill clean-up (vs not working on the clean-up) and living in proximity to the oil spill (vs further away) were suggestively associated with a possible increased risk of nonfatal MI [RR: 1.22 (0.86, 1.73) and 1.15 (0.82, 1.60), respectively]. Among oil spill workers, working for > 180 days was associated with MI [RR for > 180 days (vs 1-30 days): 2.05 (1.05, 4.01)], as was stopping working due to heat [RR: 1.99 (1.43, 2.78)]. There were suggestive associations of maximum total hydrocarbon exposure ≥3.00 ppm (vs < 0.30 ppm) [RR: 1.69 (0.90, 3.19)] and working on decontaminating oiled equipment (vs administrative support) [1.72 (0.96, 3.09)] with nonfatal MI.

CONCLUSION

This is the first study to assess the associations between oil spill exposures and MI. Results suggest that working on the spill for > 180 days and stopping work due to heat increased risk of nonfatal MI. Future research should evaluate whether the observed associations are related to specific chemical exposures or other stressors associated with the spill.

Exposure to Oil Spill Chemicals and Lung Function in Deepwater Horizon Disaster Response Workers

OBJECTIVE

The aim of this study was to assess the relationship between total hydrocarbon (THC) exposures attributed to oil spill clean-up work and lung function 1 to 3 years after the Deepwater Horizon (DWH) disaster.

METHODS

We used data from the GuLF STUDY, a large cohort of adults who worked on response to the DWH disaster and others who were safety trained but did not work. We analyzed data from 6288 workers with two acceptable spirometry tests. We estimated THC exposure levels with a job exposure matrix. We evaluated lung function using the forced expiratory volume in 1 second (FEV1; mL), the forced vital capacity (FVC; mL), and the FEV1/FVC ratio (%).

RESULTS

Lung function measures did not differ by THC exposure levels among clean-up workers.

CONCLUSION

We did not observe an association between THC exposure and lung function among clean-up workers 1 to 3 years following the DWH disaster.

Predictors of blood volatile organic compound levels in Gulf coast residents

To address concerns among Gulf Coast residents about ongoing exposures to volatile organic compounds, including benzene, toluene, ethylbenzene, o-xylene, and m-xylene/p-xylene (BTEX), we characterized current blood levels and identified predictors of BTEX among Gulf state residents. We collected questionnaire data on recent exposures and measured blood BTEX levels in a convenience sample of 718 Gulf residents. Because BTEX is rapidly cleared from the body, blood levels represent recent exposures in the past 24 h. We compared participants' levels of blood BTEX to a nationally representative sample. Among nonsmokers we assessed predictors of blood BTEX levels using linear regression, and predicted the risk of elevated BTEX levels using modified Poisson regression. Blood BTEX levels in Gulf residents were similar to national levels. Among nonsmokers, sex and reporting recent smoky/chemical odors predicted blood BTEX. The change in log benzene was -0.26 (95% CI: -0.47, -0.04) and 0.72 (0.02, 1.42) for women and those who reported odors, respectively. Season, time spent away from home, and self-reported residential proximity to Superfund sites (within a half mile) were statistically associated with benzene only, however mean concentration was nearly an order of magnitude below that of cigarette smokers. Among these Gulf residents, smoking was the primary contributor to blood BTEX levels, but other factors were also relevant.

The Gulf Long-Term Follow-Up Study (GuLF STUDY): Biospecimen collection at enrollment

The 2010 Deepwater Horizon (DWH) explosion in the Gulf of Mexico led to the largest ever marine oil spill by volume. The GuLF STUDY is investigating possible adverse human health effects associated with oil spill activities. One objective of the study was to utilize biological specimens from study participants to examine spill-related adverse health effects. This study describes the methods for collecting, processing, shipping, and storing specimens during the enrollment phase of the study. GuLF STUDY participants living in Gulf States (Alabama, Florida, Louisiana, Mississippi, and eastern Texas) were eligible to complete a home visit at enrollment, one to three years after the DWH explosion. During this visit, blood, urine, toenail and hair clippings, and house dust samples were collected. Specimens were shipped overnight to a central processing laboratory in containers with cold and ambient temperature compartments. Most blood and urine specimens were then aliquoted and stored in liquid nitrogen vapor or at -80°C, with some samples stored at -20°C. A total of 11,193 participants completed a home visit, and over 99% provided at least one biospecimen. Most participants provided blood (93%), urine (99%), and toenail clippings (89%), and 40% provided hair. Nearly all participants (95%) provided house-dust samples. Most samples were received by the laboratory one (58%) or two (25%) days after collection. These biospecimens enable investigation of a range of biomarkers of spill-related adverse health effects, and possibly some biomarkers of spill-related exposures. The biospecimen collection, handling, and storage protocols were designed to maximize current and future scientific value within logistical and budgetary constraints and might serve as a template for future studies conducted in similar time-critical and geographically dispersed settings.

The GuLF STUDY: A Prospective Study of Persons Involved in the Deepwater Horizon Oil Spill Response and Clean-Up

BACKGROUND

The 2010 Deepwater Horizon disaster led to the largest ever marine oil spill. Individuals who worked on the spill were exposed to toxicants and stressors that could lead to adverse effects.

OBJECTIVES

The GuLF STUDY was designed to investigate relationships between oil spill exposures and multiple potential physical and mental health effects.

METHODS

Participants were recruited by telephone from lists of individuals who worked on the oil spill response and clean-up or received safety training. Enrollment interviews between 2011 and 2013 collected information about spill-related activities, demographics, lifestyle, and health. Exposure measurements taken during the oil spill were used with questionnaire responses to characterize oil exposures of participants. Participants from Gulf states completed a home visit in which biological and environmental samples, anthropometric and clinical measurements, and additional health and lifestyle information were collected. Participants are being followed for changes in health status.

RESULTS

Thirty-two thousand six hundred eight individuals enrolled in the cohort, and 11,193 completed a home visit. Most were young (56.2% ≤ 45 years of age), male (80.8%), lived in a Gulf state (82.3%), and worked at least 1 day on the oil spill (76.5%). Workers were involved in response (18.0%), support operations (17.5%), clean-up on water (17.4%) or land (14.6%), decontamination (14.3%), and administrative support (18.3%). Using an ordinal job exposure matrix, 45% had maximum daily total hydrocarbon exposure levels ≥ 1.0 ppm.

CONCLUSIONS

The GuLF STUDY provides a unique opportunity to study potential adverse health effects from the Deepwater Horizon oil spill.

Ethical Issues in Environmental Health Research Related to Public Health Emergencies: Reflections on the GuLF STUDY

Health research in the context of an environmental disaster with implications for public health raises challenging ethical issues. This article explores ethical issues that arose in the Gulf Long-term Follow-up Study (GuLF STUDY) and provides guidance for future research. Ethical issues encountered by GuLF STUDY investigators included a ) minimizing risks and promoting benefits to participants, b ) obtaining valid informed consent, c ) providing financial compensation to participants, d ) working with vulnerable participants, e ) protecting participant confidentiality, f ) addressing conflicts of interest, g ) dealing with legal implications of research, and h ) obtaining expeditious review from the institutional review board (IRB), community groups, and other committees. To ensure that ethical issues are handled properly, it is important for investigators to work closely with IRBs during the development and implementation of research and to consult with groups representing the community. Researchers should consider developing protocols, consent forms, survey instruments, and other documents prior to the advent of a public health emergency to allow for adequate and timely review by constituents. When an emergency arises, these materials can be quickly modified to take into account unique circumstances and implementation details.

Gut and intestinal passage time in the Rainbow Skink (Trachylepis margaritifer): implications for stress measures using faecal analysis

Stress levels in organisms provide a rapid measure for assessing population health. Handling and capture stress, however, cause error in blood measures, so this method is rapidly being replaced by assessing levels of stress metabolites in faeces. This eliminates the source of error because there is a lag period between stress perception and the resultant stress metabolite accumulation within faeces. This lag period is correlated with specific intestinal passage time, a measure that can vary greatly between taxa, particularly amongst ectotherms. Due to two deleterious consequences associated with extended exposure of the metabolites to the intestinal environment, species that exhibit long and variable intestinal passage times are not good candidates for metabolite studies. We measured gut and intestinal passage times in Trachylepis margaritifer to ascertain whether it would be an appropriate candidate for stress metabolite studies. We first tested if barium sulphate in the meal had an effect on gut passage time at three ambient temperatures (25, 27 and 32 °C). Barium sulphate had no effect; however, temperature had a significant effect with an unexpected pattern: gut passage time was fastest at 32 °C but was slower at 27 °C than at 25 °C. We then used X-ray technology and barium sulphate-loaded meals to measure gut and intestinal passage times at 25 and 27 °C. This allowed us to observe which parts of the digestive process were responsible for increased passage times at 27 °C: the faster passage time at 25 °C was due to faster intestinal passage time; there was no difference in gastric emptying time. We assess the species to be a suitable candidate for studies using faeces to measure stress. It is imperative however, that the effect of temperature on passage rates is known and taken into account in such studies.

Acute symptoms associated with asphalt fume exposure among road pavers

BACKGROUND

Although asphalt fume is a recognized irritant, previous studies of acute symptoms during asphalt paving have produced inconsistent results. Between 1994 and 1997, the National Institute for Occupational Safety and Health (NIOSH) evaluated workers at seven sites in six states.

METHODS

NIOSH (a) measured exposures of asphalt paving workers to total (TP) and benzene-soluble particulate (BSP), polycyclic aromatic compounds, and other substances; (b) administered symptom questionnaires pre-shift, every 2 hr during the shift, and post-shift to asphalt exposed and nonexposed workers; and (c) measured peak expiratory flow rate (PEFR) of asphalt paving workers when they completed a symptom questionnaire.

RESULTS

Full-shift time-weighted average exposures to TP and BSP ranged from 0.01 to 1.30 mg/m(3) and 0.01 to 0.82 mg/m(3), respectively. Most BSP concentrations were <0.50 mg/m(3). Asphalt workers had a higher occurrence rate of throat irritation than nonexposed workers [13% vs. 4%, odds ratio (OR) = 4.0, 95% confidence interval (CI): 1.2-13]. TP, as a continuous variable, was associated with eye (OR = 1.34, 95% CI: 1.12-1.60) and throat (OR = 1.40, 95% CI: 1.06-1.85) symptoms. With TP dichotomous at 0.5 mg/m(3), the ORs and 95% CIs for eye and throat symptoms were 7.5 (1.1-50) and 15 (2.3-103), respectively. BSP, dichotomous at 0.3 mg/m(3), was associated with irritant (eye, nose, or throat) symptoms (OR = 11, 95% CI: 1.5-84). One worker, a smoker, had PEFR-defined bronchial lability, which did not coincide with respiratory symptoms.

CONCLUSIONS

Irritant symptoms were associated with TP and BSP concentrations at or below 0.5 mg/m(3).

Secondary aerosolization of viable Bacillus anthracis spores in a contaminated US Senate Office

CONTEXT

Bioterrorist attacks involving letters and mail-handling systems in Washington, DC, resulted in Bacillus anthracis (anthrax) spore contamination in the Hart Senate Office Building and other facilities in the US Capitol's vicinity.

OBJECTIVE

To provide information about the nature and extent of indoor secondary aerosolization of B anthracis spores.

DESIGN

Stationary and personal air samples, surface dust, and swab samples were collected under semiquiescent (minimal activities) and then simulated active office conditions to estimate secondary aerosolization of B anthracis spores. Nominal size characteristics, airborne concentrations, and surface contamination of B anthracis particles (colony-forming units) were evaluated.

RESULTS

Viable B anthracis spores reaerosolized under semiquiescent conditions, with a marked increase in reaerosolization during simulated active office conditions. Increases were observed for B anthracis collected on open sheep blood agar plates (P<.001) and personal air monitors (P =.01) during active office conditions. More than 80% of the B anthracis particles collected on stationary monitors were within an alveolar respirable size range of 0.95 to 3.5 micro m.

CONCLUSIONS

Bacillus anthracis spores used in a recent terrorist incident reaerosolized under common office activities. These findings have important implications for appropriate respiratory protection, remediation, and reoccupancy of contaminated office environments.

Historical risks of tuberculin skin test conversion among non-physician staff at a large urban hospital

BACKGROUND

Nosocomial transmission of Mycobacterium tuberculosis among workers at a 1000-bed inner-city hospital led to an extensive evaluation of this risk among workers with potential exposure to TB patients or laboratory specimens.

METHODS

Retrospective cohort study to determine the incidence and risk of tuberculin skin test (TST) conversions among workers employed 1/1/90 to 9/30/92.

RESULTS

Personal, community, and occupational risk factors were evaluated in 2,362 workers with potential M. tuberculosis exposure and 886 workers with no known exposure. The 33-month cumulative rate of TST conversion was 5.8% for potentially exposed workers and 2.0% for controls (RR 3.6; 95% CI; 2.2-5.8). Among workers with potential M. tuberculosis exposure, statistically significantly elevated risks were found for nurses, laboratory technicians, pharmacy workers, phlebotomists, housekeepers, clerks, emergency room workers, and emergency responders.

CONCLUSIONS

Workers with patient contact and those employed in certain occupational groups were at increased risk for occupational M. tuberculosis infection.

Pharmacokinetics of rosiglitazone in patients with end-stage renal disease

The pharmacokinetics and tolerability of a single 8-mg oral dose of rosiglitazone, an anti-diabetic agent, were compared in 10 long-term haemodialysis patients and 10 healthy volunteers. Haemodialysis patients received rosiglitazone 4 h after haemodialysis (non-dialysis day) and 3 h before haemodialysis (dialysis day). Haemodialysis did not influence rosiglitazone pharmacokinetics, and dialytic clearance was low (0.10 1/h). The mean area under the concentration-time curve (AUC(0-infinity)), the maximum observed plasma concentration (Cmax) and the half-life for rosiglitazone were similar in haemodialysis patients (non-dialysis day) and healthy individuals (2192 +/- 598 ng.h/ml versus 2388 +/- 494 ng.h/ml, 338 +/- 114 ng/ml versus 373 +/- 95 ng/ml, and 3.70 +/- 0.75 h versus 3.81 +/- 0.86 h, respectively). AUC(0-infinity) and Cmax were not markedly influenced by haemodialysis. Rosiglitazone dose adjustments are not warranted in patients with type 2 diabetes with end-stage renal failure on haemodialysis.

Lack of effect of rosiglitazone on the pharmacokinetics of oral contraceptives in healthy female volunteers

The effect of rosiglitazone (Avandia [BRL 49653C]) on the pharmacokinetics of ethinylestradiol and norethindrone was evaluated after repeat dosing of rosiglitazone with an oral contraceptive (OC; Ortho-Novum 1/35 containing norethindrone 1 mg and ethinylestradiol 0.035 mg) in a randomized, double-blind, placebo-controlled crossover study. Thirty-four healthy female volunteers received oral rosiglitazone (RSG) 8 mg + OC or matched placebo (P) + OC daily on days 1 to 14 of a 28-day OC dosing cycle; the alternate regimen was administered during a second cycle. Ethinylestradiol and norethindrone pharmacokinetics were determined from plasma concentrations on day 14. Lack of pharmacokinetic effect was prospectively defined as 90% CI for the point estimate (PE) of the ratio (RSG + OC):(P + OC) contained within a 20% equivalence range for both ethinylestradiol and norethindrone (analyzed by ANOVA). For RSG + OC and P + OC, respectively, mean ethinylestradiol AUC(0-24) was 1126 and 1208 pg.h/mL (PE: 0.92; 90% CI: 0.88-0.97), and mean norethindrone AUC(0-24) was 178 and 171 ng.h/mL (PE: 1.04; 90% CI: 1.00-1.07). Thus, rosiglitazone had no significant effects on the pharmacokinetics of ethinylestradiol or norethindrone. Coadministration of rosiglitazone with OCs does not induce metabolism of these synthetic sex steroids and is not expected to impair the efficacy of OCs or hormone replacement therapy.

The effect of acarbose on the pharmacokinetics of rosiglitazone

OBJECTIVES

To investigate whether treatment with acarbose alters the pharmacokinetics (PK) of coadministered rosiglitazone.

METHODS

Sixteen healthy volunteers (24-59-years old) received a single 8-mg dose of rosiglitazone on day 1, followed by 7 days of repeat dosing with acarbose [100 mg three times daily (t.i.d.) with meals]. On the last day of acarbose t.i.d. dosing (day 8), a single dose of rosiglitazone was given with the morning dose of acarbose. PK profiles following rosiglitazone dosing on days 1 and 8 were compared, and point estimates (PE) and associated 95% confidence intervals (CI) were calculated.

RESULTS

Rosiglitazone absorption [as measured with peak plasma concentration (Cmax) and time to peak concentration (Tmax)] was unaffected by acarbose. The area under the concentration-time curve from time zero to infinity [AUC(0-infinity)] was on average 12% lower (95% CI-21%, -2%) during rosiglitazone + acarbose coadministration and was accompanied by an approximate 1-h (23%) reduction in terminal elimination half-life t1/2 (4.9 h versus 3.8 h). This small decrease in AUC(0-infinity) appears to be due to an alteration in systemic clearance of rosiglitazone and not changes in absorption. These observed changes in AUC(0-infinity) and t1/2 are not likely to be clinically relevant. Coadministration of rosiglitazone and acarbose was well tolerated.

CONCLUSION

Acarbose administered at therapeutic doses has a small, but clinically insignificant, effect on rosiglitazone pharmacokinetics.

Rosiglitazone does not affect the steady-state pharmacokinetics of digoxin

Rosiglitazone is a potent insulin-sensitizing oral hypoglycemic agent of the thiazolidinedione class that works through activation of the peroxisome proliferator-activated receptor-gamma (PPAR-gamma) nuclear receptor and improves glycemic control in patients with non-insulin-dependent diabetes mellitus. The potential for a drug-drug interaction with oral digoxin was investigated. Subjects received both of the study regimens in a random sequence: digoxin 0.375 mg plus matching placebo for rosiglitazone orally each morning for 14 days or digoxin 0.375 mg plus 8 mg rosiglitazone orally each morning for 14 days. There was a 14-day washout period between sessions. Blood and urine were collected over 24 hours beginning on the morning of day 14 for measurement of digoxin concentrations. An equivalence statistical approach was used, with rosiglitazone considered to have no effect on the pharmacokinetics of digoxin if the 90% confidence interval (CI) for the ratio of digoxin plus rosiglitazone relative to digoxin plus placebo was completely contained within the range (0.80, 1.25) for the primary end points, AUC(0-24), and C24. Digoxin AUC(0-24) and C24 values were similar for digoxin 0.375 mg plus matching placebo (18.5 ng.h/mL and 0.579 ng/mL, respectively) and digoxin 0.375 mg plus rosiglitazone (19.1 ng.h/mL and 0.594 ng/mL, respectively). Point estimates were 1.05 (90% CI: 1.01, 1.10) for AUC(0-24) and 1.04 (90% CI: 0.98, 1.11) for C24. Oral and renal clearance were also similar between regimens. Digoxin alone or in combination with rosiglitazone was safe and well tolerated. The most common adverse experience was headache. Coadministration of digoxin with rosiglitazone had no significant effect on the safety or steady-state pharmacokinetics of digoxin.

Absorption, disposition, and metabolism of rosiglitazone, a potent thiazolidinedione insulin sensitizer, in humans

Rosiglitazone is a potent peroxisome proliferator-activated receptor gamma agonist that decreases hyperglycemia by reducing insulin resistance in patients with type 2 diabetes mellitus. The disposition of (14)C-labeled rosiglitazone was determined after oral and i.v. dosing of rosiglitazone solution, and the disposition of nonradiolabeled rosiglitazone was determined after oral dosing of tablets in this open-label, three-part, semirandomized, crossover study. The absorption of rosiglitazone was rapid and essentially complete, with absolute bioavailability estimated to be approximately 99% after oral tablet dosing and approximately 95% after oral solution dosing, and clearance was primarily metabolic. The time to maximal concentration of radioactivity and the elimination half-life for two metabolites in plasma were significantly longer than for rosiglitazone itself (4-6 h versus 0. 5-1 h, and ca. 5 days versus 3-7 h). Radioactivity was excreted primarily via the urine ( approximately 65%) and was excreted similarly after oral and i.v. dosing. The major routes of metabolism were N-demethylation and hydroxylation with subsequent conjugation, of which neither was affected by the route of drug administration. The major metabolites, those of intermediate importance, and nearly all of the trace metabolites in humans have been identified previously in preclinical studies. Rosiglitazone was well tolerated in all formulations.

Rosiglitazone has no clinically significant effect on nifedipine pharmacokinetics

To examine the effects of repeat oral dosing of rosiglitazone on the pharmacokinetics of nifedipine, a prototype CYP3A4 substrate, a randomized, open-label, crossover study was performed with two treatment phases separated by a washout period of at least 14 days. Twenty-eight healthy male volunteers received either a single 20 mg oral nifedipine dose or rosiglitazone 8 mg orally once daily for 14 days with a single 20 mg oral nifedipine dose administered on day 14. Plasma nifedipine concentrations were determined over the 24-hour period following administration of the nifedipine doses. Lack of effect was defined as the demonstration that the 90% CI was contained entirely within a symmetrical 30% range either side of unity on the loge-scale. Following rosiglitazone + nifedipine administration, the area under the nifedipine concentration-time curve from time zero to infinity (AUC(0-infinity)) was 13% lower than that after administration of nifedipine alone. This difference in nifedipine AUC(0-infinity) was not deemed to be clinically significant since the 90% CI was contained within the protocol-defined 30% range (point estimate for ratio of geometric means 0.87; 90% CI: 0.79, 0.96). Rosiglitazone had no marked effect on nifedipine peak plasma concentration (point estimate: 0.99; 90% CI: 0.73, 1.34) or time to peak concentration compared with nifedipine alone. Rosiglitazone coadministration produced a small decrease in the mean nifedipine half-life (point estimate: -0.77; 90% CI: mean difference -1.29 h, -0.25 h). Both treatment regimens were well tolerated and associated with a favorable safety profile. Rosiglitazone, at the highest dose used in clinical studies, produced a small, clinically insignificant decrease in nifedipine exposure. The very small effect on nifedipine pharmacokinetics suggests that rosiglitazone is an extremely weak inducer of CYP3A4, a characteristic that distinguishes rosiglitazone from troglitazone.

The effect of low-dose cimetidine (200 mg twice daily) on the pharmacokinetics of theophylline

The potential for nonprescription cimetidine (200 mg twice daily) to affect the pharmacokinetics of sustained-release (SR) theophylline was assessed in 26 male subjects, 13 smokers and 13 nonsmokers. This was a concentration-controlled drug interaction study in which the subjects were administered a dose of SR theophylline every 12 hours to provide a mean steady-state concentration between 8 and 15 micrograms/ml. To determine individual theophylline dose, a test dose of aminophylline was administered, and baseline theophylline pharmacokinetics were determined. Subjects remained on SR theophylline for 23 days and were treated in the following sequence: run-in phase (4 days), treatment 1 (7 days), washout (5 days), and treatment 2 (7 days). During the treatment phases, subjects received cimetidine (200 mg at approximately 08:00 and 12:00) or placebo for 7 days in a randomized crossover fashion. Theophylline pharmacokinetics were determined on days 1, 4, and 7 of both treatment phases. A large day-to-day variability in the oral clearance of theophylline was evident for the theophylline-placebo treatment and the theophylline-cimetidine treatment. Nonprescription strength cimetidine resulted in a mean 5% decrease in theophylline oral clearance on day 1 and a mean 12% decrease on days 4 and 7 combined. There were no significant differences in the cimetidine-theophylline interaction between smokers and nonsmokers. Oral clearance during the nighttime dosing interval was 13% greater than the daytime oral clearance for nonsmokers and 22% greater for smokers, showing a greater circadian rhythm for smokers. In summary, nonprescription doses of cimetidine (400 mg/day) have the potential to produce small changes in theophylline concentrations during steady-state dosing with SR theophylline; however, this effect appears less than changes that occur as a consequence of theophylline's intrasubject variability.

Safety and pharmacokinetics of an intramuscular monoclonal antibody (SB 209763) against respiratory syncytial virus (RSV) in infants and young children at risk for severe RSV disease

We conducted a multicenter, double-blind, placebo-controlled, randomized trial of a humanized monoclonal antibody against a respiratory syncytial virus (RSV) fusion protein (SB 209763) to evaluate its safety, pharmacokinetics, and fusion inhibition and neutralization titers. Forty-three infants who were either delivered prematurely ( Collapse

Key Words Collapse

MESH Headings

• Antibodies, Monoclonal/administration & dosage
• Antibodies, Monoclonal/adverse effects
• Antibodies, Monoclonal/pharmacokinetics
• Antibodies, Monoclonal, Humanized
• Antibodies, Viral/administration & dosage
• Antibodies, Viral/immunology
• Child, Preschool
• Double-Blind Method
• Female
• Half-Life
• Humans
• Infant
• Injections, Intramuscular
• Male
• Respiratory Syncytial Virus Infections/immunology
• Respiratory Syncytial Virus Infections/prevention & control
• Respiratory Syncytial Viruses/immunology

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Affiliation(s)

H C Meissner Department of Pediatrics, New England Medical Center, Tufts University School of Medicine, Boston, Massachusetts 02111, USA.
J R Groothuis
W J Rodriguez
R C Welliver
G Hogg
P H Gray
R Loh
E A Simoes
P Sly
A K Miller
A I Nichols
D K Jorkasky
D E Everitt
K A Thompson

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Effect of age and gender on the pharmacokinetics of eprosartan

AIMS

To compare the pharmacokinetics of eprosartan between young (18-45 years) and elderly (65 years) men and between young men and young, premenopausal women (18-45 years).

METHODS

Twenty-four subjects (eight subjects/group) received a single 200 mg eprosartan oral dose followed by serial blood sampling over 24 h.

RESULTS

Eprosartan was safe and well tolerated. There were no apparent differences in the pharmacokinetics of eprosartan between young females and young males or in the plasma protein binding of eprosartan (98%) for the three groups. On average, AUC (0,infinity) and Cmax values were approximately 2-fold higher in elderly men than young men [AUC (0,infinity) 95% CI: 1.22, 4.34; Cmax 95% CI: 0.98, 4.001. Similarly, unbound AUC (0,infinity) and Cmax values were, on average, approximately 2-fold higher in elderly men than young men [unbound AUC (0,infinity) 95% CI: 1.29, 4.44; unbound Cmax 95% CI: 1.02, 4.12]. tmax was delayed in the elderly men compared with young men, with a median difference of 2.5 h (95% CI: 1.00, 3.01 h).

CONCLUSIONS

No gender differences were observed in the pharmacokinetics of eprosartan. There were approximately two fold higher AUC and Cmax values for eprosartan observed in elderly men as compared with young men, most likely due to increased bioavailability of eprosartan in the elderly. Based on the excellent safety profile in the elderly in Phase III clinical trials (doses up to 1200 mg eprosartan) eprosartan can be safely administered to elderly hypertensive patients without an initial dose adjustment. Subsequently, the dose of eprosartan, as for other antihypertensive agents, may be individualized based on tolerability/response.

Response of spinal cord blood flow to the nitric oxide inhibitor nitroarginine

OBJECTIVE

The extent to which nitric oxide (NO) is involved in the modulation of spinal cord blood flow (SCBF) in the uninjured and injured cord is unknown. To elucidate these questions, the following experiments in anesthetized rats were conducted.

METHODS

Because NO is an unstable free radical with a half-life of seconds, its role can be understood through the study of the NO synthase inhibitor L-NG-nitroarginine (L-NOARG). L-NOARG was administered intravenously for 30 minutes at a dose of 100 or 500 micrograms/kg/min in 12 and 10 uninjured animals, respectively. SCBF fluctuations at C7-T1 were measured using laser doppler flowmetry. In a second set of 12 rats, L-NOARG (500 micrograms/kg/min) was administered 10 minutes before spinal cord injury using a modified aneurysm clip at C7-T1 and continued for 30 minutes thereafter.

RESULTS

In the uninjured animals, L-NOARG was associated with a dose-dependent increase in mean arterial pressure of 20 to 80% above baseline (P = 0.0001), together with a dose-related decrease in SCBF (P = 0.0373). In the injured animals, L-NOARG was associated with a 48% increase in mean arterial pressure. With L-NOARG, the changes in SCBF from baseline after injury were similar to those of noninjured controls (n = 25) and significantly less than injury controls (n = 18) or those receiving phenylephrine (n = 8).

CONCLUSION

NO synthase inhibitors, by reducing available NO, cause systemic vasoconstriction and a decrease in SCBF in the uninjured spinal cord. In the injured spinal cord, the administration of L-NOARG results in a redistribution of blood flow with an augmentation in posttraumatic SCBF at the injury site.

Reduction of paraphimosis with hyaluronidase

The use of hyaluronidase facilitates reduction of paraphimosis. It acts by dispersing extracellular edema, permitting easy reduction of the foreskin. Its use is applicable both in the hospital and outpatient setting. Hyaluronidase is widely available and keeps well if refrigerated. It is effective for children and adults.

Preservation of continence after posterior sagittal surgery

PURPOSE

An animal study was performed to evaluate the effect of posterior sagittal pararectal mobilization on anorectal sphincter function.

MATERIALS AND METHODS

We initially divided 11 juvenile pigs into 3 groups: group 1-anesthesia alone (3), group 2-posterior sagittal incision alone (4) and group 3-posterior sagittal incision with unilateral pararectal dissection (4). Two animals in group 1 subsequently underwent posterior sagittal incision with circumferential pararectal dissection (group 4). The anal canal was preserved intact in all animals. Anorectal sphincter manometry was performed preoperatively, and 2, 4, 8 and 12 weeks postoperatively. Electromyography was performed 12 weeks postoperatively. Anorectal sphincter muscle complexes were harvested for histological examination.

RESULTS

All animals had postoperative bowel continence. Postoperatively manometry revealed no difference from preoperative measurements in all study groups (p = 0.90). Electromyography and histological examination of the anorectal sphincters were normal in all but 2 animals. Denervation injury and histological atrophy were detected after repair of inadvertent enterotomy in 1 animal following unilateral pararectal dissection, and polyphasic motor unit potentials implying reinnervation were detected in another after circumferential pararectal mobilization.

CONCLUSIONS

These results indicate that posterior sagittal incision and unilateral pararectal mobilization cause no permanent injury to the anorectal sphincter. However circumferential pararectal dissection or repair of a rectal injury may cause measurable changes in sphincter function.

Excretion of tolbutamide metabolites in young and old subjects

Tolbutamide (1 g/70 kg) was administered as a single intravenous dose to 31 healthy, non-smoking, drug-free males between 23 and 87 years old and the total amounts of hydroxy and carboxytolbutamide excreted in 24 h were measured. There was a significant decrease in the urinary recovery of both metabolites with age. The reason for these findings is not known at the present time and may be associated with the decrease in creatinine clearance observed in these subjects or other changes in the pharmacokinetics of tolbutamide which are currently being investigated.

A systematic approach to examining the patient with nail disease

The majority of patients who present to the clinician for podiatric care do so because of complaints involving the nail and its surrounding structures. All too often the clinician's examination of the nail is incomplete and in many instances completely overlooked. The authors present a systematic approach to the examination of the patient who presents with nail pathology.

Parasites of the Water Rat, Hydromys-Chrysogaster, From Victoria and South-Australia

Eighty-one H. chrysogaster from nineteen localities in Victoria and South Australia were examined for helminths. One acanthocephalan Corynosoma stanleyi: and one cestode, Hymenolepis diminuta, were found. Of the trematodes six were identified to species: Echinoparyphium hydromyos, Fibricola minor, F. intermedius, Microphaflus minutus, Maritrema oocysta and Plagiorchis jaenschi; two were placed in the families Heterophyidae, and Psilostomidae, both new locality records; and two new species Notocotylus sp. nov. and Paramonostomum sp. nov. were found. There were six nematode species: Synhimantus australiensis, Antechiniella suffodiax, Antechiniella sp., Woolleya hydromyos as well as Parastrongyloides sp. and a heteroxynematid both new host records. H. diminuta was the most prevalent helminth, with M. minutus and S. australiensis the most prevalent trematode and nematode respectively. A checklist of helminths from H. chrysogaster is given and comparisons between infections of Tasmanian, Victorian and South Australian hosts are made. Thirty-three of these water rats, trapped live in Victoria, were also examined for protozoa. Klossiella hydromyos, Toxoplasma gondii and Sarcocystis sp. were found. Twenty of the Victorian hosts were examined for ectoparasites. Three mites; Paraspeleognathopsis derricki, Murichirus parahydromys, and Radfordia sp.; one tick, Zxodes tasmani; one louse, Hoplopleura bidentata; and three flea species, Acanthopsylla rothschildi and Echidnophaga spp. were found.

Managing data quality through automation

Traditional definitions of data quality deal primarily with individual data sets and the data collection process. Today's standards for ensuring data quality have not changed with respect to the desired results, but have simply been expanded to take advantage of modern technology. Computers are used to acquire, review, store, analyze, and report data. Because each of these steps can be automated, the need for human intervention and manual review is minimized. As a result, the potential for invalid data to reach the data analysis stage has increased significantly. To reduce this potential, efforts must be devoted to developing automated procedures that cover every conceivable validation possibility. Relationships between data and data sets must be well defined [1], and data base support that facilitates ready access to the data for the purpose of analysis must be provided. For small data sets, automation may therefore be impractical; but for large, interrelated data sets, automation is highly desirable. Computer automation has therefore expanded the traditional concept of ensuring data quality to include a complex array of interrelated tasks that must be properly managed to achieve the desired results.

Physical-chemical compatibility of cromolyn sodium nebulizer solution--bronchodilator inhalant solution admixtures

Cromolyn sodium nebulizer solution, 1%, is physically and chemically compatible (stable) for up to 60 minutes when mixed in vitro with metaproterenol, isoproterenol, isoetharine, epinephrine, terbutaline, and acetylcysteine inhalant solutions, respectively. Similarly, cromolyn does not adversely affect the stability of the individual bronchodilator/mucolytic drugs in the admixtures. Adding a bronchodilator/mucolytic agent to a cromolyn nebulizer solution should not negatively influence the in vivo efficacy or safety of either active ingredient.

Automated differential cell counting on a sector of the normal human hippocampus: the influence of age

The neurons and the glia of the human hippocampus are notoriously vulnerable in various pathological conditions including those linked to ageing. There may even be differences between the young and the old in the absence of manifest disease. Using an image analyser, systematic measurements of cell numbers in the region of the Sommer (Hl) sector of the human hippocampus have been made on post-mortem tissue from thirty-seven female and forty-nine male subjects aged between 15 and 96 years. In fifteen male and fifteen female subjects both hemispheres were available for analysis so that measurements were made on a total of 116 hemispheres. For each specimen the fresh volume of the hemisphere was measured and corrections subsequently made for changes in size which occurred during fixation, processing, mounting and staining. After all the correction factors had been applied the number of nucleolated neurons was found to fall by about 3.6% per decade (P less than 0.0001). There was no significant age-related change in the number of glia. Marked individual variations were found.

Rapid GC method for quantitation of nifedipine in serum using electron capture detection

For studying the pharmacokinetics of nifedipine after single doses, a rapid, specific, reliable gas chromatographic assay procedure for nifedipine in serum is developed. Using a single-step solvent extraction or a bonded-phase column extraction and electron capture detection, an assay sensitivity of 10 to 25 ng/ml can be achieved using 0.25 ml of serum. The assay quantitates intact nifedipine and separates it reproducibly from its nitro- and nitrosopyridine derivatives.

Interferences in a high pressure liquid chromatographic assay of theophylline

Interference by salicylic acid was noted in a high pressure liquid chromatographic assay of theophylline in serum. The acid eluted very close to theophylline in a mobile phase consisting of 0.01 M acetate buffer, pH 4.0, containing 28% methanol on a C-18 reverse-phase column. The two peaks could be resolved by switching to a mobile phase containing 18% methanol, 1.6% acetonitrile, and 1.6% acetic acid in water. However, in this mobile phase traces of the extracting solvent, ethyl acetate, caused a sharpening of the theophylline peak leading to spuriously high results. The problem was overcome by using chloroform to extract the theophylline from serum.

Effects of total plasma concentration and age on tolbutamide plasma protein binding

Tolbutamide plasma protein binding at different total tolbutamide concentrations was determined in 44 healthy, nonsmoking, drug-free men from 23 to 87 yr old. The data showed that unbound drug increased with total tolbutamide plasma concentration and with age, but that neither the binding equilibrium constant nor the number of binding sites correlated with age. The increase in unbound fraction with age could be partially explained by the decrease in albumin concentration in elderly subjects. Results of multiple linear regression analysis indicated that, although age had a considerably greater influence than albumin concentration, total tolbutamide concentration was the most important determinant of the unbound fraction. Thus, both age and total plasma concentration may affect tolbutamide kinetics.

Using the Quantimet 720 image analyzing computer to count nucleolated neurones in the human brain

An approach to the automatic counting of neurones in the human hippocampus is described which uses a modified Quantimet 720 image analyzing computer. Previous work with this and similar machines has attempted to use size alone to discriminate between the various types of cell which are present in any section of central nervous system tissue. Serious errors may then result since agglomerates of small cells and cell fragments can bae confused with single large cells. Instead, 2 electron devices have been designed and built which allow nucleolated neurones, defined as those objects having a grey phase and a black phase both within designated area limits, to be distinguished from all other cells. The mean values for absolute cell numbers and for cell density were within 5% of those obtained by traditional manual methods. The operation of both electronic devices is described and circuit diagrams given for one of them. The other is beyond the scope of this paper, but has been fully reported elsewhere.

Human blood preservation: effect on in vitro protein binding

In vitro plasma protein binding for phenytoin, meperidine, and bretylium tosylate was affected by the type of preserved human blood used for its estimation. Fresh heparinized plasma and serum gave equivalent fractions bound at the concentrations studied for all three drugs. However, the in vitro plasma binding of phenytoin and meperidine decreased 9-50% when estimated in fresh citrated plasma or commercially available lyophylized human serum at the concentration levels investigated. The fraction of bretylium tosylate bound to plasma protein decreased 30-40% when estimated in fresh citrated plasma but was unchanged when estimated in the lyophylized human serum.

An animal model for assessing pain-on-injection of antibiotics

The paw-licking response of rats to a subplantar injection of an antibiotic was used as an indicator of the pain caused by that antibiotic. Good agreement with clinical findings was obtained with cefoxitin, cephalothin, cephradine, cefazolin, cephaloridine, and carbenicillin. Incorporation of a local anesthetic into the diluent of an irritating antibiotic reduced the number of paw-licking episodes. This rat paw model offers a simple and rapid means of estimating pain-on-injection following intramuscular injection of antibiotics to humans and may be applicable to other drugs as well.

Variation with age in the volumes of grey and white matter in the cerebral hemispheres of man: measurements with an image analyser

The total volumes and relative quantities of grey and white matter have been measured in sixty-five normal male and sixty-five normal female cerebral hemispheres. Fixed hemisphere volume was found to fall linearly at 3.5% per decade for men from 641 ml at the age of 20 to 463 ml at the age of 100. For women the decrease was 1.9% per decade from 531 ml at 20 years to 462 ml at 100 years. After correction for the effects of fixation and for the secular increase in brain size, it was concluded that mean hemisphere volume remained roughly constant between the ages of 20 and 50 years (558 ml for men, 474 ml for women). After the age of 50 the mean volume in both sexes fell at about 2% per decade. The ratio of the volumes of grey to white matter was the same for the two sexes at all ages. Its mean value was 1.3 at the age of 20, falling to 1.1 at the age of 50, then rising steadily to over 1.5 at 100 years. It is impossible in practice to correct these measurements for the effects of fixation or secular change. Fourteen hemispheres from thirteen elderly female dements were also measured. The total volume was 18% lower than for an age-matched group of normals, but the ratio of grey to white matter was identical.

A basic program to correct for split cell error in particles classified by the logarithm of their profile areas

A program is presented, written in the BASIC computer language, to correct the errors which occur when cell profiles are counted in thin sections of tissue. Given the numbers of profiles in each of M size classes, and the thickness and area of the sections examined, the program calculates the number of cells in each of these classes per mm3 of tissue. The mathematical method is briefly described and it is shown that a useful level of accuracy may be obtained when the correction procedure is used in the study of non-spherical cells.

Correlation of in vitro susceptibility with in vivo efficacy in mice for cefoxitin in comparison with cephalosporins

Agar minimal inhibitory concentrations and mouse protection test effective doses were determined for each of four beta-lactam antibiotics against each of 12 Gram-negative and 3 Gram-positive bacterial cultures. The beta-lactamase activity of these cultures also was studied. The data were examined to determine whether relative in vivo efficacies could be predicted from relative in vitro activities. Although such predictions were quite accurate for cefoxitin and cefazolin, this was not true for cefamandole or for cephalothin. Such poor predictability was not necessarily associated with the susceptibility of these cephalosporins to hydrolysis by bacterial beta-lactamases. Although the clinical significance of these observations is not known, these data emphasize that relative in vitro activities should be used only with caution to estimate in vivo efficacies, since not all compounds show the excellent predictability observed here for cefazolin and cefoxitin.

Urinary metabolites of 3a,4,5,6,7,7a-hexahydro-3-(1-methyl-5-nitro-1H-imidazol-2-yl)-1,2-benzisoxazole in the dog

The antiprotozoal drug 3a,4,5,6,7,7a-hexahydro-3-(1-methyl-5-nitro-1H-imidazol-2-yl)-1,2-benzisoxazole (I), which exhibits activity against trypanosomiasis, is also antibacterial in vivo. Since the urine from a dog dosed with I showed a broader spectrum of antibacterial activity than I itself, metabolites from this urine were isolated and partially characterized. The metabolites were mono- and dihydroxy-substituted species with the hydroxyl groups on carbons 4--7 of the hexahydrobenzisoxazole ring. These observations led to the synthesis of several such hydroxy derivatives of I, and their properties fully supported the proposed positions of metabolic hydroxylation. One synthetic compound, the 6,7-cis-dihydroxy compound, exhibited higher antibacterial activity against Salmonella schottmuelleri in mice and greater trypanocidal activity in vivo against Trypanosoma cruzi (Brazil strain) than I.

Thienamycin, a new beta-lactam antibiotic. I. Discovery, taxonomy, isolation and physical properties

A new beta-lactam antibiotic, named thienamycin, was discovered in culture broths of Streptomyces MA4297. The producing organism, subsequently determined to be a hitherto unrecognized species, is designated Streptomyces cattleya (NRRL 8057). The antibiotic was isolated by adsorption on Dowex 50, passage through Dowex 1, further chromatography on Dowex 50 and Bio-Gel P2, and final purification and desalting on XAD-2. Thienamycin is zwitterionic, has the elemental composition C11H16N2O4S (M.W. = 272.18) and possesses a distinctive UV absorption (lambda max = 297 nm, epsilon = 7,900). Its beta-lactam is unusually sensitive to hydrolysis above pH8 and to reaction with nucleophiles such as hydroxylamine, cysteine and, to a lesser degree, the primary amine of the antibiotic itself. The latter reaction results in accelerated inactivation at high antibiotic concentrations.

Cefoxitin and cephamycins: microbiological studies

The cephamycins are a family of beta-lactam antibiotics that are produced by actinomycetes and are structurally similar to the cephalosporins. They are characterized by the presence of a 7-alpha-methoxyl group, which confers unusually high resistance to beta-lactamases. Cefoxitin, the first semisynthetic cephamycin, is resistant to almost all beta-lactamases. Cefoxitin retains the 3-carbamoyl group of cephamycin C and thus has excellent metabolic stability. Cefoxitin is bactericidal and almost devoid of any inoculum effect. Active against many cephalothin-resistant gram-negative bacteria, cefoxitin demonstrates a very broad spectrum that includes indole-positive Proteus and many strains of Serratia. In contrast to that of the cephalosporins, cefoxitin's spectrum of activity against anaerobic pathogens includes Bacteroides fragilis. The therapeutic effectiveness of cefoxitin in experimental infections in mice confirms the excellent characteristics of this semisynthetic cephamycin and indicates that it should be a very valuable agent for treatment of bacterial infections.