Comparison of four plating media for isolating Vibrio cholerae

Two brands of thiosulfate citrate bile salts sucrose agar and Monsur taurocholate tellurite gelatin (TTG) agar were compared with two newly developed media, sucrose tellurite teepol agar and Vibrio parahaemolyticus agar for isolation and identification of Vibrio cholerae. The thiosulfate citrate bile salts sucrose and TTG agars were the best selective media, whereas sucrose tellurite teepol agar was the poorest. Both TTG and sucrose tellurite teepol agars were good for use in follow-up serological tests, whereas only TTG agar could be used for follow-up oxidase tests. In our opinion TTG agar has more advantages for cholera research laboratories routinely culturing large numbers of patients for cholera on a daily basis and where media needs can be accurately predicted. In contrast, in smaller clinical laboratories or in laboratories investigating epidemics, thiosulfate citrate bile salts sucrose agar is best because it is commercially available and easy to prepare and can be used to distinguish colonies of suspect V. cholerae from V. parahaemolyticus.

Collagen in 155 human bladders

The percentage of bladder collagen, as obtained by the dosage of hydroxyproline, was determined in autopsy specimens from 48 female and 107 male cadavers. The average percentage of collagen in the human bladder is 57.4 per cent (+/- 9) of the dry weight of insoluble protein. There is good correlation (r = 0.55) between detrusor and trigone collagen content. There is no significant difference between pre- and postpuberty age groups in relative collagen content. In females more than 50 years of age there is a significant increase in collagen.

Narcotic antagonist treatment: clinical experience with naltrexone

Narcotic antagonist (naltrexone) treatment experience with 22 opioid addicts over a 29-month period shows that the mean duration of receipt of naltrexone was 6.2 weeks, and 12 subjects (55%) continued in treatment after cessation of naltrexone for an average of 5.6 weeks. Analysis of physical and behavioral measured revealed no toxicity, indicating that naltrexone appears to be a safe drug. Clinical evaluation of the patients receiving naltrexone suggests that ingestion of naltrexone provides a degree of external control, reducing the preoccupation with heroin and releasing energy for the pursuit of other goals. Subject follow-up at an average of 45.3 weeks after cessation of naltrexone indicated that 11 (58%) were known to be abstinent, and 9 (47%) subjects were employed compared with 3 (16%) employed at the onset of treatment.

A multiple electrode cochlear implant

The University of Melbourne Departments of Otolaryngology and Electrical Engineering (UMDOLEE) receiving and stimulating component of a multiple-electrode cochlear implant hearing prosthesis produces constant stimulation. It has a stimulating pulse shape that minimizes the production of toxic substances and loss of metal from the electrodes, and this is achieved with a biphasic rectangular waveform where the first phase is negative with respect to ground. The duration of each stimulus phase in 180 msec, which is long enough to allow low levels of current stimulation, and short enough to permit rates of 1000 pulses/second to be achieved. In order to be consistent with our present understanding of the perception of pitch, the device permits the independent stimulation of a number of electrodes. Furthermore, to electrically isolate the stimulus to small areas, there is the capacity to vary the current and set the threshold independently at individual electrodes. The phase and amplitude of the pulses to neighbouring electrodes with also be varied to assist in localizing the current flow. The pattern to stimulation to individual or groups of electrodes can also be altered to enable studies to be carried out to determine ways of conveying frequency and intensity information over a more normal dynamic range.

Implications of inorganic/organic interconversion on fluxes of arsenic in marine food webs

An organic form of arsenic is commonly encountered in marine organisms; in greysole and shrimp, it accounted for all arsenic found in muscle tissue. It has been isolated from flounder tissue by two independent procedures; it was hydrophilic, cationic, and was not decomposed to inorganic arsenic by hot nitric and sulfuric acids. NMR spectroscopy indicated all nonexchangeable protons to be equivalent; they behaved more like N-methyl protons than As-methyl protons. High-resolution mass spectroscopy from a heated probe yielded a spectrum corresponding to tetramethylarsonium (AsMe4+); the authentic ion, however, had TLC and ion-exchange behavior different from that of the natural product. Infrared spectrometry likewise produced conflicting or uninterpretable data. Decomposition of the compound for analytical purposes was accomplished by dry ashing under oxidizing conditions. Sea urchins, like trout, converted arsenic to an organic form, but to a more limited degree. Arsenic found naturally in sea urchins and in a species of macroalga was also organic. In individual containers, sea urchins were fed on the alga for 7 weeks. During this time they consumed 0.203 +/- 0.075 mg total As and excreted only 0.036 +/- 0.015 mg as feces. Measurement of inorganic As in the seawater did not account for the discrepancy, but measurements of total As did (0.202 +/- 0.095 mg). Sea urchins, like humans, appear to be able to rapidly excrete these organic forms of arsenic.

Bacteroides fragilis resistant to the administration of clindamycin

The susceptibility of Bacteroides fragilis to the administration of clindamycin, and the efficacy of this agent in Bacteroides infections are well documented. Clindamycin-resistant strains of B. fragilis were isolated from two patients with bacteremia at two institutions. Clinically significant resistance to clindamycin therapy has not been noted previously in B. fragilis infections.

Limited Arsenic Dispersion in Sea Water, Sediments, and Biota Near a Continuous Source

Moreton’s Harbour, Newfoundland, has been exposed to arsenic-bearing drainage and leaching from a stibnite mine for at least 38 yr and possibly longer than 84 yr. Measurements of inorganic arsenic in sea water and sediments and total arsenic in some marine organisms revealed a very limited influence of continuous exposure to arsenic in the small harbor. Arsenic concentrations in surface water declined to normal within 200 m, and in sediments within 50 m. Animals did not show significantly higher levels nearer the mine, with the exception of the sea urchin Strongylocentrotus droebachiensis, which accumulated significantly higher levels of arsenic adjacent to the mine site.

Growth Rates of Intertidal Molluscs as Indicators of Effects of Unexpected Incidents of Pollution

Shells of living molluscs contain a record of previous growth rate if the time interval between check marks is known. The check marks in Mytilus edulis and Littorina littorea are probably annual marks. Growth rates of Mytilus in 1969, the year of significant elemental phosphorus pollution at Long Harbour, Newfoundland, were no different from those in preceding or succeeding years. No Littorina alive in 1969 occurred at Long Harbour, but they were abundant at other locations. This sort of analysis, used with caution because effects of pollutants may be confounded with effects of other variables, provides a method of examining nonlethal effects of unexpected polluting events.

Dispersion in a natural population of three-spined sticklebacks

Territorial male three-spined sticklebacks, Gasterosteus aculeatus form trachurus, in a splash pool were dispersed uniformly. Their nests tended to occur in sheltered locations, but the presence of exposed nests and the uniform dispersion suggested that all the suitable space for territories was used. If original males, removed from their territories, did not return, new males became territorial.