In vitro susceptibilities of Bartonella and Rickettsia spp. to fluoroquinolone antibiotics as determined by immunofluorescent antibody analysis of infected Vero cell monolayers.

The in vitro susceptibilities of Bartonella and Rickettsia spp. to different concentrations of ciprofloxacin, levofloxacin, ofloxacin and sparfloxacin in Vero cell cultures, were determined by enumeration of immunofluorescent-stained bacilli. After incubation in a CO(2)-enriched atmosphere, inocula were replaced and tested with media containing 12 different concentrations of each antibiotic in replicate for each species and the monolayers were re-incubated. Growth status was determined by evaluation of immunofluorescent staining bacilli. Effective inhibitory antibiotic dilution endpoints were determined by counting Bartonella- and Rickettsia-specific fluorescent foci across a range of antibiotic dilutions with an epi-fluorescent microscope, and were compared with an antibiotic-negative control. Based upon the use of C(max):MIC and AUC:MIC data, levofloxacin exhibited activity against Bartonella elizabethae and B. quintana.

Homicide on the job: workplace and community determinants.

Homicide is the second leading cause of death on the job for workers in the United States. To identify workplace-level predictors of homicide risk, a case-control study of worker killings in North Carolina in 1994-1998 was conducted. Workplaces were the units of analysis: case workplaces (n = 105) were those where a worker was killed during the study period, while controls (n = 210) were a density sample of North Carolina workplaces, matched on time and industry sector. Potential risk and protective factors were assessed in telephone interviews with workplace managers. Associations were measured by the exposure odds ratio and 95% confidence interval, estimated via conditional logistic regression. Characteristics associated with notably higher risk included being at the current location for 2 years or less (odds ratio (OR) = 5.3, 95% confidence interval (CI): 2.2, 12.6), having only one worker (OR = 2.9, 95% CI: 1.2, 7.2), and having night (OR = 4.9, 95% CI: 2.7, 8.8) or Saturday (OR = 4.2, 95% CI: 1.9, 9.2) hours. Workplaces with only male employees (OR = 3.1, 95% CI: 1.5, 6.5) or with African-American or Asian employees were also more likely to experience a killing. While few of the preceding risk factors are directly modifiable through workplace interventions, it is important to identify them before developing or evaluating preventive measures.

Disposition and functions of clarithromycin in human THP-1 monocytes during stimulated and unstimulated conditions.

The macrolide antibiotics are bacteriostatic agents interfering with protein synthesis but they are taken up by phagocytic cells, e.g. macrophages, neutrophils and fibroblasts which take up infectious organisms into phagosome-lysosomal vaculoes. Recent studies have suggested that these macrolide antibiotics block the spread of infections by mechanisms associated with the inflammation process. Herein is a study with clarithromycin using human THP-1 monocytes, a phagocytic cell which has not been studied to date. Clarithromycin was rapidly taken up by the monocytes (approximately 1%) utilizing both saturable carrier and passive processes at pH 7.4 but was exclusively passive at pH 6.8 and 5.0. The carrier process was energy and temperature dependent and appeared to be linked to certain ion channels. Efflux of the drug was rapid and complete in 1 hr. Intracellular disposition showed 74% in the cell sap and 11% in the nucleus. Upon stimulation with zymogen A or bacteria significant increases of uptake occurred in the isolated lysosome-phagosomes. Examination showed that initially clarithromycin treatment triggered the release of NO, H2O2, IL-1 and TNFalpha from the monocytes, known mediators of inflammation, but also mediators which cause bacterial cell death or apoptosis. The activity of the monocyte marker hydrolytic enzyme NAG was elevated at this time as well as protein kinase C activity. Treatment from 2-4 hr with clarithromycin appeared to reverse this process in that the chemical mediator release was reduced along with the activities of hydrolytic enzymes, e.g. NAG and cathepsin D with no evidence of lipid peroxidation and protective SOD enzyme activity elevation. The latter effects of the antibiotic would be useful in blocking the spread of infection or inflammation from the original site. The normal bacterial static killing effects of clarithromycin was evident at 24 but not 2 hr in both extracellular free bacteria and those bacteria phagocytosed by the THP-1 monocytes.

Killed on the clock: a population-based study of workplace homicide, 1977-1991.

BACKGROUND: This paper describes the epidemiology of workplace homicides in North Carolina, with emphasis on the circumstances. METHODS: Workplace homicide victims were identified by and data were abstracted from the North Carolina medical examiner system. RESULTS: Workplace homicide rates are highest for men, older and self-employed workers, minorities and specific occupations, especially taxi drivers. Robberies, mostly in retail settings, accounted for half of the cases, while 20% were known to involve disputes, the contexts of which differed by sex. Women were most likely to be killed by estranged partners. CONCLUSIONS: Preventive strategies need to address the specific contexts in which workplace homicide occurs, such as retail and taxi robberies, and law enforcement officers interacting with suspects. A workplace response to domestic violence is also needed. Other areas for future research and intervention include environmental modifications, employee screening and training, and identifying more inclusive occupational data sources.

In vitro susceptibilities of Rickettsia and Bartonella spp. to 14-hydroxy-clarithromycin as determined by immunofluorescent antibody analysis of infected vero cell monolayers.

The in vitro susceptibilities of Rickettsia akari, Rickettsia conorii, Rickettsia prowazekii, Rickettsia rickettsii, Bartonella elizabethae, Bartonella henselae and Bartonella quintana to different concentrations of clarithromycin, 14-hydroxy-clarithromycin (the primary metabolite of clarithromycin) and tetracycline in Vero cell cultures, were determined by enumeration of immunofluorescently-stained bacilli. The extent of antibiotic-induced inhibition of foci was recorded for each dilution of antibiotic and compared with an antibiotic-negative control. Based upon MIC data, clarithromycin alone is highly active against all three Bartonella spp., R. akari and R. prowazekii, while 14-hydroxy-clarithromycin is active against R. conorii, R. prowazekii and R. rickettsii. Further testing is warranted in animal models and human clinical trials, to examine the activity of both clarithromycin and its primary metabolite and to define further the role of clarithromycin in therapy, particularly of infections caused by obligate intracellular bacteria such as Rickettsia and Bartonella spp.

Discontinuation rates for protease inhibitor regimens containing ritonavir 600 mg versus ritonavir 400 mg plus saquinavir 400 mg.

OBJECTIVE: A retrospective study was performed to determine whether twice-daily ritonavir 400 mg plus twice-daily saquinavir 400 mg (ritonavir 400/saquinavir 400) was better tolerated than ritonavir 600 mg twice daily (ritonavir 600). A secondary objective was to determine whether the rate of discontinuation due to therapeutic failure differed between the two ritonavir regimens. DESIGN: The study was a retrospective chart review. Data collected included ritonavir dose; length of ritonavir therapy; reason for discontinuation; HIV-1 RNA prior to and at discontinuation of ritonavir therapy; CD4+ count; and antiretroviral therapy prior to, concomitant with, and initiated after ritonavir therapy. SETTING: Patient charts were reviewed in a university teaching hospital clinic. PATIENTS: Patients were identified through a search of the pharmacy database from December 18, 1995, to December 18, 1997. Patients were > 18 years old, but not restricted by gender or race. MAIN OUTCOME MEASURES: The main outcome measures were frequency of discontinuation of ritonavir due to intolerance or due to lack of therapeutic efficacy. RESULTS: The search identified 116 patients, including 57 patients taking ritonavir 400/saquinavir 400 and 54 patients taking ritonavir 600. Five patients on other ritonavir regimens were excluded. Significantly fewer patients receiving ritonavir 400/saquinavir 400 (14%) discontinued ritonavir due to intolerance compared with ritonavir 600 (37%; p = 0.002). Discontinuations due to therapeutic failure were not significantly different: 8.8% for ritonavir 400/saquinavir 400 and 7.4% for ritonavir 600, despite the fact that ritonavir/saquinavir therapy followed another protease inhibitor in 41 patients (73.2%) compared with 12 patients (24.5%) for ritonavir 600 (p = 0.001). CONCLUSIONS: Ritonavir 400/saquinavir 400 is better tolerated than ritonavir 600.

Underascertainment of child abuse mortality in the United States.

CONTEXT: Mortality figures in the United States are believed to underestimate the incidence of fatal child abuse. OBJECTIVES: To describe the true incidence of fatal child abuse, determine the proportion of child abuse deaths missed by the vital records system, and provide estimates of the extent of abuse homicides in young children. DESIGN AND SETTING: Retrospective descriptive study of child abuse homicides that occurred over a 10-year period in North Carolina from 1985-1994. CASES: The Medical Examiner Information System was searched for all cases of children younger than 11 years classified with International Classification of Diseases, Ninth Revision codes E960 to E969 as the underlying cause of death and homicide as the manner of death. A total of 273 cases were identified in the search and 259 cases were reviewed after exclusion of fetal deaths and deaths of children who were not residents of North Carolina. MAIN OUTCOME MEASURE: Child abuse homicide. RESULTS: Of the 259 homicides, 220 (84.9%) were due to child abuse, 22 (8.5%) were not related to abuse, and the status of 17 (6.6%) could not be determined. The rate of child abuse homicide increased from 1.5 per 100000 person-years in 1985 to 2.8 in 1994. Of all 259 child homicides, the state vital records system underrecorded the coding of those due to battering or abuse by 58.7%. Black children were killed at 3 times the rate of white children (4.3 per 100000 vs 1.3 per 100000). Males made up 65.5% (133/203) of the known probable assailants. Biological parents accounted for 63% of the perpetrators of fatal child abuse. From 1985 through 1996, 9467 homicides among US children younger than 11 years were estimated to be due to abuse rather than the 2973 reported. The ICD-9 cause of death coding underascertained abuse homicides by an estimated 61.6%. CONCLUSIONS: Using medical examiner data, we found that significant underascertainment of child abuse homicides in vital records systems persists despite greater societal attention to abuse fatalities. Improved recording of such incidences should be a priority so that prevention strategies can be appropriately targeted and outcomes monitored, especially in light of the increasing rates.

A subtype of sporadic prion disease mimicking fatal familial insomnia.

OBJECTIVE: To establish a variant of sporadic prion disease as the sporadic form of fatal familial insomnia (FFI). BACKGROUND: FFI is a recently described prion disease characterized clinically by severe sleep impairment, dysautonomia, and motor signs, and pathologically by atrophy of thalamic nuclei, especially the medial dorsal and anterior ventral, and of the inferior olive. FFI is linked to the D178N mutation coupled with the methionine codon at position 129 in the prion protein gene (PRNP). It is also identified by the properties of the abnormal prion protein (PrP(Sc)), which has the relative molecular mass of 19 kDa, corresponding to the so-called type 2, and a marked underrepresentation of the unglycosylated form relative to the diglycosylated and monoglycosylated forms. METHODS: Clinical, pathologic, PrP(Sc), and PRNP data from 5 subjects with a sporadic prion disease phenotypically similar to FFI were collected and analyzed. RESULTS: All 5 subjects had a disease clinically similar and histopathologically virtually identical to FFI. PrP(Sc) type 2 was present in all subjects in amount and distribution similar to those of FFI. However, the PrP(Sc) did not show the striking underrepresentation of the unglycosylated isoform of the protein that is characteristic of FFI. Moreover, none of the subjects had the D178N PRNP mutation but all were homozygous for methionine at codon 129. CONCLUSION: This condition is likely to represent the sporadic form of FFI and the term "sporadic fatal insomnia" is proposed.

Alcohol in aviation-related fatalities: North Carolina, 1985-1994.

BACKGROUND: Previous studies examining the role of alcohol in aviation safety have been limited to pilots and the estimated degree of alcohol involvement in fatal aviation crashes was susceptible to selection bias because alcohol testing was not conducted on a routine basis. This study examines the magnitude of and factors related to alcohol involvement in both pilot and non-pilot aviation fatalities. METHODS: We analyzed medical examiner data on all victims who died in civilian aircraft crashes in North Carolina during 1985-94, complemented by crash investigation data from the National Transportation Safety Board. RESULTS: During the 10-yr study period, the North Carolina Medical Examiner Information System recorded 337 aviation-related fatalities including 111 pilots. Alcohol testing was performed on 91% of the pilots and 72% of the non-pilot occupants. Of the victims who were tested for alcohol, 12% (7% of the pilots and 15% of non-pilot occupants) had positive blood alcohol concentrations (BACs), ranging from 0.02 to 0.14%. All four victims with BACs greater than 0.10% were pilots aged 20-29 yr who were fatally injured in nighttime general aviation crashes. In crashes of commercial flights, none of the pilots tested positive for alcohol, whereas 20% of the non-pilot occupants had positive BACs. CONCLUSIONS: Intoxicated flying, particularly among young general aviation pilots, is still a valid concern. The aviation safety implications of alcohol use by passengers of commercial flights should be further examined.

Treatment and prophylaxis of disseminated Mycobacterium avium complex in HIV-infected individuals.

OBJECTIVE: To review the pathophysiology, epidemiology, treatment, and prophylaxis of disseminated Mycobacterium avium complex (MAC) infection in HIV-infected individuals. DATA SOURCES: A MEDLINE (January 1966-July 1997) and AIDSLINE (January 1980-July 1997) search of basic science articles pertinent to the MAC infection in HIV-infected patients. STUDY SELECTION AND DATA EXTRACTION: All articles were considered for possible inclusion in the review. Pertinent information, as judged by the authors, was selected for discussion. DATA SYNTHESIS: The organism, epidemiology, and pathophysiology of disseminated MAC are discussed for background. A review of clinical trials for the treatment and prophylaxis of disseminated MAC are presented, along with unresolved issues concerning these topics. CONCLUSIONS: The incidence of disseminated MAC has increased dramatically with the AIDS epidemic. The infection can lead to increased morbidity and mortality in HIV-infected patients. Treatment regimens for patients with a positive culture for MAC from a sterile site should include two or more drugs, including clarithromycin. Prophylaxis against disseminated MAC should be considered for patients with a CD4 cell count of less than 50/mm3.

Striatal [125I]RTI-55 binding sites in cocaine-abusing humans.

1. Previous experiments in this laboratory found that striatal [3H]WIN 35428 binding was increased in post mortem specimens from human cocaine users (Little et al, 1993a). Although structurally similar, preliminary studies have suggested that [3H]WIN 35428 and the related cocaine congener [125I]RTI-55 differ in some respects pharmacologically. 2. The present experiments tested the hypothesis that striatal [125I]RTI-55 binding would be increased, as was [3H]WIN 35428 binding, in post mortem specimens from cocaine users compared to matched controls. 3. However, computer-generated parameters derived from saturation experiments found only trends toward increased Bmax and decreased affinity (increased KD) in the cocaine users. The magnitude of the increases were notably smaller than the statistically significant increases previously found in high affinity [3H]WIN 35428 binding in these same subjects. 4. Evidence from the present and earlier experiments suggests that cocaine exposure may induce conformational changes in the dopamine transporter.

Fatal residential fires: who dies and who survives?

CONTEXT: The United States has one of the highest fire fatality rates in the developed world, and three quarters of these deaths are in residential fires. OBJECTIVE: To compare characteristics of those who die and those who survive in the same residential fire. DESIGN: Data on fatal residential fires were collected from the medical examiner and interviews with local fire officials. SETTING: North Carolina. SUBJECTS: Persons in residential fires with at least 1 fatality in a 1-year period. MAIN OUTCOME MEASURE: Dying vs surviving a fatal residential fire that occurred with more than 1 person at home. RESULTS: Of the 190 decedents, 124 (65%) were male, 78 (41%) were home alone, and 69 (53%) of 130 adults who had blood alcohol measured were intoxicated (blood alcohol content >22 mmol/L [100 mg/dL]). Of the 254 persons present during fires in which more than 1 person was at home, 112 died. Individuals more likely to die (high-vulnerability group) were younger than 5 years or 64 years or older, had a physical or cognitive disability, or were impaired by alcohol or other drugs (risk of death for group, odds ratio [OR], 4.01; 95% confidence interval [CI], 2.29-7.03). The presence of an adult with no physical or cognitive disabilities who was unimpaired by alcohol or other drugs (a potential rescuer) reduced the risk of death in the high-vulnerability group (OR, 0.49; 95% CI, 0.24-0.99) but not the low-vulnerability group. Overall, a functioning smoke detector lowered the risk of death (OR, 0.39; 95% CI, 0.18-0.83). CONCLUSIONS: Smoke detectors were equally effective in both low- and high-vulnerability populations. The high-vulnerability group was more likely to survive if, in addition to a smoke detector, a potential rescuer was present. Further research should seek to identify prompts that facilitate speedy egress from a burning structure and that can be incorporated into residential fire alarm systems.

Serotonin transporter binding sites and mRNA levels in depressed persons committing suicide.

The serotonin transporter (5-HTT) has been found altered in postmortem brain samples from persons committing suicide, but the results of radioligand binding studies have been inconsistent. In the present series of experiments, autoradiographic radioligand binding and in situ hybridization techniques were utilized to examine 5-HTT function in the brains of 8 depressed subjects who had committed suicide, and matched controls. It was hypothesized that depressed subjects would demonstrate decreased numbers of 5-HTT binding sites and mRNA; however, [125I]RTI-55 binding to the 5-HTT was not different in the midbrain, hippocampus, or frontal cortex of depressed subjects. Also, 5-HTT mRNA levels in dorsal and median raphe nuclei were not different between controls and depressed subjects. The current results, although limited in scope because of the small number of subjects included, offer no evidence that alterations in the 5-HTT occur in pertinent brain regions of depressed individuals.

Fatal occupational injuries in a southern state.

Fatal occupational injuries were studied using data from medical examiners' reports in North Carolina for the years 1977-1991. Cases were defined as deaths due to accidents or homicide at the workplace, and populations at risk were estimated from the 1980 and 1990 US Censuses. Mortality rate ratios and proportionate mortality ratios were used as measures of association, and the population attributable risk percentage was used as an indicator of the burden of injury. Standard weights for direct age-adjustment of rates were obtained from the total state workforce. There were 2,524 eligible deaths-83 percent from unintentional traumatic injuries, 14 percent from homicide, and the remainder from other causes. This report focuses on unintentional trauma deaths, which were strongly associated with the wood production, fishing, and transportation industries. Elderly, African-American, and self-employed workers had higher fatality rates than members of other groups. Among male workers, motor vehicle crashes were the principal cause of death on the job, followed by falling objects, machinery, and falls. The industries contributing the largest proportions of these deaths were construction, trucking, agriculture, and logging (population attributable risk percentages were 16.8%, 8.8%, 7.9%, and 6.9%, respectively). The fatality patterns of female workers were different: Numbers of deaths from homicide and unintentional trauma were equal, and 27% of the latter deaths occurred in one catastrophic fire. Decentralized and rural industries were the most hazardous, but many deaths were outside the current jurisdiction of occupational safety and health agencies. These patterns suggest that greater scrutiny of such industries, through both research and intervention, is warranted.

In vitro susceptibilities of Bartonella henselae, B. quintana, B. elizabethae, Rickettsia rickettsii, R. conorii, R. akari, and R. prowazekii to macrolide antibiotics as determined by immunofluorescent-antibody analysis of infected Vero cell monolayers.

The in vitro susceptibilities of Bartonella (Rochalimaea) henselae, B. quintana, B. elizabethae, Rickettsia akari, R. conorii, R. prowazekii, and R. rickettsii to different concentrations of azithromycin, clarithromycin, dirithromycin, erythromycin, and roxithromycin in Vero cell cultures were evaluated. Bartonella and Rickettsia spp. were allowed to initiate infection of the antibiotic-free Vero cell monolayers, which were maintained in 16-chamber microscope slides in the absence of antibiotics at 32 degrees C in a CO2-enriched atmosphere. The monolayers were then incubated for 3 h to allow for initial host cell intracellular penetration by infecting species. After inoculation, inocula were replaced and tested with media containing 12 different concentrations of each antibiotic in replicate (10 wells of each antibiotic dilution) for each species, and the monolayers were reincubated. Tetracycline served as the control. Growth status of Bartonella spp. and Rickettsia spp. was determined by evaluation of immunofluorescent staining bacilli. Five days later, when antibiotic-free, control-infected cell monolayers demonstrated significant fluorescence, media were removed for all cell monolayers, the monolayers were fixed, and all specimens were stained with standard indirect immunofluorescent antibody reagents. Fluorescent foci were enumerated by counting such foci on random fields visualized with an epifluorescence microscope. The extent of antibiotic-induced focus inhibition was recorded for each dilution of antibiotic and compared with that of an antibiotic-negative control. Effective antibiotic dilution endpoints for inhibition of Bartonella and Rickettsia proliferation, as judged by absence of increase of significant fluorescence (as compared with no-growth controls), were enumerated by determining the number of cell culture chambers at various antibiotic dilutions that were negative or positive for significant Bartonella- or Rickettsia-specific fluorescence. All of the macrolide agents tested were readily active against all three Bartonella organisms, and azithromycin, clarithromycin, and roxithromycin may have potential in the treatment of Rickettsia infections. Animal model-based clinical trials are warranted to define the specific treatment role of the newer macrolide antibiotics.

Alteration of brain dopamine and serotonin levels in cocaine users: a preliminary report.

OBJECTIVE: This study tested the hypothesis that cocaine depletes dopamine levels in the brain. METHOD: Levels of dopamine, serotonin, and their metabolites in the frontal cortex and striatum of nine cocaine users and nine matched control subjects who had never used cocaine were determined from postmortem autopsy material. RESULTS: The cocaine users had significantly lower dopamine levels and higher serotonin levels in the frontal cortex than the control subjects. Levels in other brain areas did not differ between the two groups. CONCLUSIONS: Alterations of dopamine and serotonin levels might contribute to symptoms of cocaine withdrawal and craving.