Morphometric analysis of horizontal canal nerves of chronically diabetic rats.

Horizontal canal nerves of 3-, 6-, 9-, and 12-month-diabetic rats were compared with those of age-matched controls. The myelin sheaths of the horizontal canal nerves in diabetic rats were thinner than those of age-matched controls (mean +/- SD 0.63 +/- 0.04 micron (n = 16) vs. 0.71 +/- 0.05 micron (n = 9); p < 0.0001, one-tailed t test). Regression analysis revealed that myelin sheath thickness did not correlate with severity of diabetes, but myelin thinning did occur as a function of the duration of diabetes (p < 0.05, regression ANOVA). The progression of myelin thinning over time is consistent with the possibility of an accelerated decline in vestibular function with age in diabetic patients. That myelin thinning did not correlate with the severity of diabetes suggests that this thinning is not directly related to the aging effects attributed to nonenzymatic glycosylation of myelin proteins. Multivariate analysis revealed a significant difference between diabetic and control groups when fiber diameter and intrasheath diameter were considered together (p < 0.008, canonical discriminant-function analysis). Diabetic and control groups did not differ significantly in total nerve fiber counts. In the diabetic group, however, nerve fiber counts were higher in animals with higher blood glucose levels (p < 0.02, linear-regression ANOVA; r2 = 0.49). The finding of higher nerve fiber counts in more severely diabetic rats is consistent with an earlier transmission electron microscopic finding of false myelinated nerve fiber profiles in micrographs from more severely diabetic rats. These false profiles are believed to represent phagocytosis-like Schwann cell reactions against their own myelin, triggered by excess myelin glycosylation.

Filgrastim (r-metHuG-CSF) and its potential use in the reduction of radiation-induced oropharyngeal mucositis: an interim look at a randomized, double-blind, placebo-controlled trial.

We wished to determine if filgrastim administration to chemotherapy/radiation therapy-naive patients receiving external-beam irradiation for head-and-neck malignancies would reduce the incidence and severity of oral/oropharyngeal mucositis. Patients were randomized to receive subcutaneous injections of either filgrastim or placebo beginning on day 1 of radiation and continuing daily throughout treatment. Study medication was titrated to keep the neutrophil count between 10 x 10(9) and 30 x 10(9)/l. The left and right buccal mucosa, hard palate, and posterior pharyngeal wall were scored weekly, by a blinded evaluator using two different scales, and the most severe score per week was used in data analysis. Fourteen of a planned 54 patients were randomized (8 filgrastim, 6 placebo), and were evaluable for a planned interim analysis. No statistically significant between-group differences were seen in mean worst scores across time using repeated measures analysis of variance (Hickey, p = 0.231; WHO, p= 0.288). At almost all timepoints, however, the worst mean scores were lower in patients treated with filgrastim compared with those in patients treated with placebo, and the number of severe (i.e., grade 3) mucositis scores was significantly lower in the filgrastim-treated group. Filgrastim may decrease the severity of radiation-induced oral/oropharyngeal mucositis.

Prevention of Vibrio vulnificus infections. Assessment of regulatory educational strategies.

CONTEXT: Vibrio vulnificus-related disease caused by eating contaminated raw oysters prompted California to implement regulatory educational initiatives in 1991. OBJECTIVE: To assess California guidelines and education efforts with regard to the prevention of V. vulnificus infections in Los Angeles County and to evaluate compliance with state regulations mandating posting of warning signs concerning risks of eating raw oysters. DESIGN: Review of epidemiologic investigations of V. vulnificus infections in Los Angeles County between 1993 and 1995; telephone interviews of patients or surrogates; and a survey of restaurants serving raw oysters in Los Angeles County. SETTING: General community. MAIN OUTCOME MEASURES: Prior warning of patients and posting of warning signs in restaurants. RESULTS: Recent cases of V. vulnificus infections in Los Angeles County suggest that a unique, vulnerable group (uninsured Hispanic men with viral or alcoholic liver disease) has not been reached through education efforts. Of a total of 11 cases, information regarding being warned about the hazard of eating raw shellfish was available for 8; of these, only 1 case was reported as having been warned, but he had misunderstood the preventive message. Warning signs were not posted adequately in more than 50% of restaurants surveyed and one third of these establishments had signs in English only. Warnings were never located on dining tables and rarely included in menus. CONCLUSION: A more effective strategy is required to prevent V.vulnificus infections in Los Angeles County.

Transmission of hepatitis B virus to multiple patients from a surgeon without evidence of inadequate infection control.

BACKGROUND: Although about 1 percent of surgeons are infected with hepatitis B virus (HBV), transmission from surgeons to patients is thought to be uncommon. In July 1992, a 47-year-old woman became ill with acute hepatitis B after undergoing a thymectomy in which a thoracic-surgery resident who had had acute hepatitis B six months earlier assisted. METHODS: To determine whether the surgeon transmitted HBV to this patient and others, we conducted chart reviews, interviews, and serologic testing of thoracic-surgery patients at the two hospitals where the surgeon worked from July 1991 to July 1992. Hepatitis B surface antigen (HBsAg) subtypes and DNA sequences from the surgeon and from infected patients were determined. RESULTS: Of 144 susceptible patients in whose surgery the infected surgeon participated, 19 had evidence of recent HBV infection (13 percent). One of the hospitals was selected for additional study, and none of the 124 susceptible patients of the other thoracic surgeons at this hospital had evidence of recent HBV infection (relative risk, infinity; 95 percent confidence interval, 4.7 to infinity). No evidence was found for any common source of HBV other than the infected surgeon. The HBsAg subtype and the partial HBV DNA sequences from the surgeon were identical to those in the infected patients. Transmission of the infection was associated with cardiac transplantation (relative risk, 4.9; 95 percent confidence interval, 1.5 to 15.5) but not with other surgical procedures. The surgeon was positive for hepatitis B e antigen and had a high serum HBV DNA concentration (15 ng per milliliter). Our investigations identified no deficiencies in the surgeon's infection-control practices. CONCLUSIONS: In this outbreak there was surgeon-to-patient HBV transmission despite apparent compliance with recommended infection-control practices. We could not identify any specific events that led to transmission.

An outbreak of cholera from food served on an international aircraft.

In February 1992, an outbreak of cholera occurred among persons who had flown on a commercial airline flight from South America to Los Angeles. This study was conducted to determine the magnitude and the cause of the outbreak. Passengers were interviewed and laboratory specimens were collected to determine the magnitude of the outbreak. A case-control study was performed to determine the vehicle of infection. Seventy-five of the 336 passengers in the United States had cholera; 10 were hospitalized and one died. Cold seafood salad, served between Lima, Peru and Los Angeles, California was the vehicle of infection (odds ratio, 11.6; 95% confidence interval, 3.3-44.5). This was the largest airline-associated outbreak of cholera ever reported and demonstrates the potential for airline-associated spread of cholera from epidemic areas to other parts of the world. Physicians should obtain a travel history and consider cholera in patients with diarrhoea who have travelled from cholera-affected countries. This outbreak also highlights the risks associated with eating cold foods prepared in cholera-affected countries.

Cloning, expression, and purification of a functional nonacetylated mammalian mitochondrial chaperonin 10.

An intact mouse mitochondrial chaperonin 10 has been cloned, sequenced, and overexpressed in Escherichia coli as a fusion protein harboring an oligohistidine tail at its COOH terminus. The latter was added to simplify protein purification. The purified protein is free of contaminating groES from the bacterial host cells. Edman degradation reveals that the initiator Met residue of the recombinant protein is removed in vivo, similar to the authentic chaperonin 10 purified from rat liver mitochondria. However, in contrast to the latter, the amino-terminal Ala residue of the recombinant protein is not acetylated; the molecular mass determined by electrospray ionization mass spectrometry is 12,350.9 +/- 2.6 daltons, in agreement with that predicted for the nonacetylated protein (12,351.2 daltons). Facilitated protein folding experiments with ribulose-biphosphate carboxylase, under "nonpermissive" in vitro conditions, demonstrate that the recombinant protein is fully functional with groEL. Thus, both the initial rates of protein folding and final yields observed with this heterologous combination are virtually identical to those obtained with groEL and groES. More important, like the authentic protein purified from mitochondria, the recombinant mitochondrial chaperonin 10, but not groES, is functionally compatible with the heptameric chaperonin 60 of mammalian mitochondria.

Swimming-associated cryptosporidiosis.

In July and August 1988, an outbreak of gastroenteritis affected 44 of 60 (73%) persons from 5 separate swimming groups who had used the same swimming pool in Los Angeles. Cryptosporidium was identified in 5 of 8 (63%) stool specimens, and the clinical picture was consistent with Cryptosporidium infection. Resistance of Cryptosporidium to chlorine, an inadequately maintained pool filtration system, repeated exposure to pool water, and possible continuing pool contamination may have contributed to ongoing transmission. Cryptosporidium should be considered a potential etiologic agent of gastroenteritis associated with recreational water use.

An outbreak of bacteremic Campylobacter jejuni infection.

During September 1980, an outbreak of bacteremic Campylobacter jejuni infection occurred in metropolitan Los Angeles. The outbreak was recognized when blood cultures obtained from 11 previously healthy persons with acute febrile illnesses (characterized in over 80% by fever, diarrhea, and headaches) were positive for C. jejuni. All recovered after an illness that lasted a mean of 8 days. A surveillance system failed to reveal a concomitant outbreak of gastroenteritis. Isolates had identical biochemical characteristics, susceptibility patterns to antimicrobial agents, and serotypes. Isolates from 2 patients were found to be susceptible to bactericidal activity of normal human serum. When bacteremic case-patients were matched with healthy controls, a significant association (p less than 0.05, odds ratio 10) between illness and consumption of processed turkey was established. Although turkey was not available for culture, and processing of turkey theoretically destroys Campylobacter, turkey carcasses are known to be heavily contaminated with the pathogen.

Food-borne disease in hospitals: prevention in a changing food service environment.

The results of an investigation into an outbreak of food-borne disease at a hospital in Los Angeles County are reported. The outbreak occurred at a luncheon buffet for nonpatient visitors attending an event at the hospital, which was catered by the hospital. The food source and etiologic agent(s) responsible for the outbreak were not identified by our investigation. However, several issues relating to the changing character of hospital food provision and their implications for prevention of food-borne disease in hospitals were conspicuous. Two trends apparent in hospital food service are toward increased use of foodstuffs prepared by wholesale food manufacturers and more frequent invitation to community groups to meet within hospital facilities and use hospital catering services. We found that (1) hospital kitchens in Los Angeles County are undersurveyed with respect to frequency of sanitary inspections; (2) hospitals have no mechanism whereby to assess the sanitary inspection record of wholesale food manufacturers from whom they purchase foodstuffs; and (3) crossover of food items prepared for nonpatient hospital visitors, including catered foods, to the inpatient menu occurs. The potential risks for a food-borne disease outbreak among compromised inpatients resulting from these factors are discussed, and measures to reduce such risk are proposed.

Salmonellosis outbreak on transatlantic flights; foodborne illness on aircraft: 1947-1984.

In March 1984, 186 cases of gastroenteritis due to Salmonella enteritidis were reported after 29 flights to the United States on an international airline. An estimated 2,747 passengers on flights to the United States were affected. Illness was associated with flying supersonic or first class (odds ratio = 15, p less than 0.001). Eating food from the first-class menu was associated with illness (p = 0.09), and eating a tourist-class entree was protective (p less than 0.01). In 23 reported outbreaks of foodborne illness on aircraft, Salmonella has been the most common pathogen (seven outbreaks), followed by Staphylococcus (five outbreaks), and Vibrio species (five outbreaks). Outbreaks are most often the result of an improper temperature for preparation or for holding food in the flight kitchens. Serving the flight crew meals from one kitchen carries the risk that the entire crew will become ill.