Characterization of Vibrio fluvialis-like strains implicated in limp lobster disease.

Studies were undertaken to characterize and determine the pathogenic mechanisms involved in a newly described systemic disease in Homarus americanus (American lobster) caused by a Vibrio fluvialis-like microorganism. Nineteen isolates were obtained from eight of nine lobsters sampled. Biochemically, the isolates resembled V. fluvialis, and the isolates grew optimally at 20 degrees C; none could grow at temperatures above 23 degrees C. The type strain (1AMA) displayed a thermal reduction time (D value) of 5.77 min at 37 degrees C. All of the isolates required at least 1% NaCl for growth. Collectively, the data suggest that these isolates may embody a new biotype. Pulsed-field gel electrophoresis (PFGE) analysis of the isolates revealed five closely related subgroups. Some isolates produced a sheep hemagglutinin that was neither an outer membrane protein nor a metalloprotease. Several isolates possessed capsules. The isolates were highly susceptible to a variety of antibiotics tested. However, six isolates were resistant to erythromycin. Seventeen isolates harbored plasmids. Lobster challenge studies revealed that the 50% lethal dose of a plasmid-positive strain was 100-fold lower than that of a plasmid-negative strain, suggesting that the plasmid may enhance the pathogenicity of these microorganisms in lobsters. Microorganisms that were recovered from experimentally infected lobsters exhibited biochemical and PFGE profiles that were indistinguishable from those of the challenge strain. Tissue affinity studies demonstrated that the challenge microorganisms accumulated in heart and midgut tissues as well as in the hemolymph. Culture supernatants and polymyxin B lysates of the strains caused elongation of CHO cells in tissue culture, suggesting the presence of a hitherto unknown enterotoxin. Both plasmid-positive and plasmid-negative strains caused significant dose-related intestinal fluid accumulations in suckling mice. Absence of viable organisms in the intestinal contents of mice suggests that these microorganisms cause diarrhea in mice by intoxication rather than by an infectious process. Further, these results support the thermal reduction data at 37 degrees C and suggest that the mechanism(s) that led to fluid accumulation in mice differs from the disease process observed in lobsters by requiring neither the persistence of viable microorganisms nor the presence of plasmids. In summary, results of lobster studies satisfy Koch's postulates at the organismal and molecular levels; the findings support the hypothesis that these V. fluvialis-like organisms were responsible for the originally described systemic disease, which is now called limp lobster disease.

[Comparative study of the use of nifedipine and captopril in hypertensive emergencies]. / Estudo comparativo do uso da nifedipina e do captopril em urgências hipertensivas.

Forty patients with hypertensive crises, whose pressure levels had not satisfactorily decreased after intravenous furosemide 20 mg, were selected in the Emergency Ward. These patients were divided in two groups. The ones in group A received sublingual nifedipine 10 mg and the others in group B received oral captopril 50 mg. These drugs were repeated after 30 minutes to the maximum of three doses or until obtaining diastolic blood pressure less than 115 mmHg. Most patients (77.5%) had their blood pressure reduced to the proposed values after the first dose, and the remaining ones (22.5%) reacted to the therapy only after the administration of the subsequent doses. No side effects were observed. All patients were discharged from the emergency unit and were sent for follow-up in the outpatient service. The use of nifedipine and captopril has proved to be an effective treatment for hypertensive crises.

Assessing levels of airborne bioallergens in New York City.

Sampling of airborne ragweed and other pollen grains in the City of New York is described as it took place during the months of August and September 1973. Three sampling stations participated in the program. This effort was meant to serve as the forerunner of a citywide volunteer pollen sampling network based on the cooperation of existing health care providing institutions, schools, and stations of the operational sampling network of the New York City Department of Air Resources. Monitoring stations were set up on the roof of Cooper Union School of Engineering at 51 Astor Place in downtown Manhattan, at the Boyce Thompson Institute for Plant Research, Inc. at Yonkers, N.Y. and use was made of the data supplied by Middlesex General Hospital, New Brunswick, N.J. Seasonal results of ragweed pollen sampling, undertaken at the downtown New York City location of Cooper Union with the swing-shield intermittant rotoslide sampler, are similar to those of studies undertaken in the 1940's and 1950's with the Durham slide sampler in the New York metropolitan area. Comparison of the collected data with converted data obtained in 1979 at Long Island Jewish-Hillside Medical Center with the aid of a Durham gravity slide sampler shows the trend similarity of the data collected by us in 1973 and those obtained in 1979. Collected data of the 1973 ragweed season were supplied to the New York City news media on a daily basis, as a much appreciated service to the public.