Biomedical subjects
Publications and source records attributed to E Israel.
From 1981 through 1987, a total of 1,068 AIDS cases were diagnosed in Maryland; 62.8 percent occurred in the homosexual/bisexual male cohort followed by intravenous drug abusers, 21.8 percent. Time trends suggest that proportionally fewer cases of AIDS will occur among homosexual/bisexual males and transfusion patients, and more cases will appear among intravenous drug abusers and heterosexuals.
The clinical and epidemiologic features of vibrio infections occurring over 15 y in a hospital adjacent to the Chesapeake Bay were examined. Microbiologic techniques included the use of thiosulfate citrate bile salts sucrose (TCBS) medium on all stool specimens. Among 40 vibrio isolates from 32 patients, eight species were identified: V. parahaemolyticus (16), V. vulnificus (10), non-O1 V. cholerae (7), V. mimicus (3), V. hollisae (1), V. fluvialis (1), V. alginolyticus (1), and an unnamed halophilic vibrio. Sources included stool (13), wound (11), sputum (3), ear (3), bone (1), and gallbladder (1). While illnesses were diverse, they were relatively mild and self-limited with no mortality. The mild clinical spectrum and especially lack of mortality are in sharp contrast to the findings of previous reports. Even with the proximity to the bay and use of optimal isolation techniques, the demonstrated incidence of vibrio infections was low (1.6/100,000/y). The routine use of TCBS medium, which has been advocated for high-risk areas, was not cost-effective.
An outbreak of Clostridium perfringens food poisoning occurred among attendees of a firehouse luncheon. The predominant symptoms of diarrhea (100%) and abdominal pain (81%) among case-patients, the mean incubation period (13.4 h), and the mean duration of illness (21.2 h) were all characteristic of C. perfringens enteritis. Roast beef, although not epidemiologically implicated, was the most likely vehicle of transmission. Fecal specimens from case-patients contained a median C. perfringens spore count of greater than 10(6) and yielded isolates that were heat sensitive and predominantly nonhemolytic, produced C. perfringens enterotoxin A, and, in the majority of specimens (four of five), were identical in serotype. Food samples were negative. This outbreak demonstrates that following enumeration of C. perfringens from a suitable number of fecal specimens from case-patients, serotyping of the isolates may be helpful in implicating C. perfringens as the cause of foodborne illness. This is especially true when implicated food items test negative or are no longer available for testing.
Luminal epithelial projections formed during bronchoconstriction define interstices in which liquid can collect. Liquid in these interstices could amplify the degree of luminal compromise due to muscular contraction in at least two distinct ways. First, the luminal cross-sectional area is reduced by simple filling of the interstices. Second, if the surface tension (gamma) of the air-liquid interface is positive, the pressure drop across the interface produces an additional inward force that can further constrict the airway. We present a theoretical treatment of these two mechanisms together with data which suggest that both may significantly amplify the luminal narrowing due to airway smooth muscle contraction, particularly in small airways when gamma is high. To qualitatively assess the effects of altered gamma, guinea pig lungs with normal and altered airway liquid lining layers were frozen and studied while fully hydrated by low-temperature scanning electron microscopy. Airway gamma was altered in these animals by intratracheal instillation of 0.5 mg lysoplatelet-activating factor (lyso-PAF). The interstices of normal airways were dry, whereas the interstices of airways with altered surface lining layers were liquid filled. In addition, the surfactant inhibitory properties of lyso-PAF, 2-arachidonyl-PAF, and dipalmitoyl phosphatidylcholine (DPPC) were measured with a pulsating bubble surfactometer, using surfactant TA as the model surfactant. Minimal gamma (gamma min) of surfactant TA alone was 4.0 +/- 0.2 dyn/cm; a 5% mixture of lyso-PAF with surfactant TA resulted in a significantly (P less than 0.02) greater gamma min of 8.8 +/- 1.8 dyn/cm. In contrast, 2-arachidonyl-PAF and DPPC had minimal effects on gamma min of surfactant TA.
Isocapnic hyperpnea (ISH) of cold air induces bronchoconstriction in many asthmatic subjects. Although this response is well described, it is unclear whether this bronchoconstriction is related to the release of bronchoactive mediators. We examined whether pretreatment with LY171883, a competitive antagonist of leukotriene D4 activity via LTD4 receptors, reduced the bronchospastic response to cold air ISH in asthmatics using a randomized, double-blind, two-phase crossover design. In 20 subjects, 2 wk of treatment with either LY171883 600 mg twice a day or placebo did not result in a change in FEV1 (3.45 +/- 0.21 L placebo versus 3.59 +/- 0.20 L LY171883; p greater than 0.05). Nineteen subjects underwent cold-air ISH; LY171883 increased the geometric mean respiratory heat loss required to reduce the FEV1 by 20% (PD20RHE) from 1.00 kcal/min with placebo to 1.24 kcal/min with LY171883 (p less than 0.05). A similar difference was noted when responses were expressed as a function of minute ventilation. LY171883 produced greater shifts in the PD20RHE in more reactive subjects (r = 0.69, p less than 0.002). Among 11 different symptom scores recorded by 18 subjects, there was a significant decrease in daytime chest tightness with LY171883 (p less than 0.03). The increase in PD20RHE while the subjects received LY171883 is consistent with the hypothesis that LTD4 becomes available during cold-air ISH and may mediate bronchoconstriction. The small magnitude of the effect on the PD20RHE may be due to the role of other mediators in cold-air-induced bronchoconstriction or, alternatively, to an inadequate blockade of LTD4 effects.
Persons who are receiving evaluation and treatment for sexually transmitted diseases are at moderately increased risk for acquiring HIV infections. The scope of STD clinic services should be broadened to include counseling, education, and referral services for health needs related to risk of HIV infection.
We continue to advance our knowledge regarding susceptible hosts. As people live longer, society is faced with a new problem of dealing with ever-increasing numbers of elderly with inadequate immune defense. HIV infections, cancer drugs, and steroids continue to add more persons to this pool. As we prepare to move into the twenty-first century, historical perspectives on our past triumphs and failures allow us to feel confident to meet the challenges ahead in preventing life-threatening illnesses in persons with immune deficiency.
Between January 1, 1987 and December 31, 1987, a total of 184 adverse events were reported to have occurred within 28 days following diphtheria, tetanus, pertussis (DTP) immunization in Maryland. More than half the reports (54 percent) were of serious or major vaccine reactions. Screaming episodes were the most frequently reported serious reaction, having occurred in 64 (35 percent) of the reports.
Review of 2219 admissions to an intensive care unit at a large urban hospital from 1983 to 1985 revealed an epidemic of cardiac arrests during the evening shift from January 1984 to March 1985. Of the 88 evening-shift cardiac arrests during this time, one specific nurse (Nurse 14) was the care giver for 57 (65%). Eight of ten epidemic-period patients who experienced shift-specific circadian recurrences of cardiac arrests were patients of Nurse 14. No therapeutic intervention and no other health care provider was as strongly associated with evening-shift cardiac arrests as was Nurse 14. Multiple logistic regression analysis demonstrated that when risk of cardiac arrest was adjusted for age, sex, severity of illness, and postoperative status, patients of Nurse 14 were 47.5 times more likely to experience arrest than were other nurses' patients. An expert determined that, compared with other nurses, the cardiac arrests among Nurse 14's patients were more likely to be consistent with unexplained hyperkalemia, to be unexpected in timing, and to be inconsistent with the clinical course. The epidemic ceased when Nurse 14 left employment at the intensive care unit in March 1985. Epidemiologic surveillance of adverse outcomes in health care settings is recommended.
To assess the prevalence and associated risk factors for human immunodeficiency virus (HIV) infection in patients attending inner-city clinics for sexually transmitted diseases in Baltimore, we screened 4028 patients anonymously, of whom 209 (5.2 percent) were seropositive for HIV. HIV-seropositivity rates were higher among men (6.3 percent) than women (3.0 percent) (P less than 0.001) and among blacks (5.0 percent) than whites (1.2 percent) (P less than 0.02). Among men, but not women, HIV seroprevalence increased markedly and steadily up to the age of 40. In men, HIV seropositivity was independently associated with increased age, black race, a history of homosexual contact, and the use of parenteral drugs. In women, a history of parenteral drug use or of being a sexual partner of a bisexual man or parenteral drug user were independently predictive of HIV seropositivity. In men, HIV seropositivity was also associated with a history of syphilis or a reactive serologic test for syphilis, and in women, with a history of genital warts. Since these associations were independent of the type and number of reported sexual partners, they raise the possibility that sexually transmitted diseases that disrupt epithelial surfaces may be important in the transmissibility of HIV. In addition, on a self-administered questionnaire, one third of HIV-infected men and one half of infected women did not acknowledge previous high-risk behavior for HIV exposure. These data suggest that patients at clinics for sexually transmitted diseases represent a group at high risk for HIV infection, and that screening, counseling, and intensive education should be offered to all patients attending such clinics.
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Salmonella enteritidis ser. enteritidis was isolated from patrons and employees of three restaurants in a restaurant chain in Maryland during August and September 1985. Isolates from all three restaurants had identical plasmid profiles; this profile was present in 13 of 40 randomly selected S. enteritidis isolates received by the Maryland state health department laboratory during a comparable time period. The outbreak in one restaurant resulted in at least 71 illnesses, with 17 persons known to have been hospitalized. Scrambled eggs served on a "breakfast bar" were implicated as the vehicle of transmission in this restaurant, with eggs a possible vehicle in another of the three restaurants. The data point out the risks associated with improper handling of eggs in food service establishments, provide further evidence for the observed association between S. enteritidis and eggs in the northeastern United States, and demonstrate the utility of plasmid analysis in investigation of outbreaks involving common Salmonella serotypes.
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Ten cases of typhoid fever occurred between 24 August and 1 September 1986 in the vicinity of Silver Spring, Md. Shrimp salad served in a fast-food restaurant was implicated as the source of infection. Stool cultures were obtained from 104 employees, and serum Vi antibodies were assayed in 97 of the employees. Salmonella typhi was isolated from stool cultures of an 18-year-old asymptomatic female employee, who was a food handler. A high level of Vi antibodies (79.0 micrograms/ml), measured by radioimmunoassay, was found in her serum. She had emigrated from an endemic area at the age of 14 years and had visited that endemic area 2 years previously. The causal relation between the carrier and the 10 cases of typhoid fever was confirmed by a common bacteriophage type, denoted "degraded Vi resembling O," in the S. typhi isolates. This phage type is rare in the western hemisphere but common in the endemic area from which the carrier had emigrated. The high level of Vi antibody in the asymptomatic carrier, in contrast to the lower levels in the convalescent- and postimmunization-phase sera, facilitated the identification of the source infection in this outbreak. This radioimmunoassay offers a rapid and standardized method for identifying carriers of S. typhi.
Tracheobronchopathia osteochondroplastica (TO) is a rarely described disorder which historically has not been frequently recognized antemortem. Studies by computerized tomography (CT) and bronchoscopy now permit a definitive antemortem diagnosis and can obviate a more invasive diagnostic evaluation. We describe two cases of TO presenting as right middle lobe collapse, discuss the clinical and pathologic features, and outline an approach to its evaluation using CT and bronchoscopic study.
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Voluntary physician reporting of adverse drug events (ADEs) in their patients remains the single most important source of information on serious and rare ADEs. Yet, substantial underreporting exists and the factors producing it are unclear. We surveyed 3000 randomly chosen physicians by mailed questionnaire to determine their knowledge about the reporting system, attitudes toward reporting, and their past behavior in reporting the ADEs they had detected. Responses numbered 1121. Only 57% were aware of the Food and Drug Administration's reporting system. While 418 physicians had detected an ADE in their practices during the previous year, only 21 physicians reported these events directly to the Food and Drug Administration. The physicians appear to appreciate the safety issues involved in prescription drug use and view reporting as a professional obligation; however, the current reporting system is considered inconvenient.