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Biomedical subjects

C M Kunin

Publications and source records attributed to C M Kunin.

At least 73 records · Page 4Linked to original sources

Osmoprotective activity for Escherichia coli in mammalian renal inner medulla and urine. Correlation of glycine and proline betaines and sorbitol with response to osmotic loads.

Escherichia coli are protected against hypertonic NaCl by human urine. We have shown that this is due in part to the presence of glycine betaine and proline betaine. Several investigators have proposed that betaines and sorbitol are concentrated in the cells of the renal inner medulla where they exert a protective role against urea and extracellular osmotic forces. E. coli was used in the present studies as an "osmosensor" to detect osmoprotective activity in mammalian tissues. The greatest activity was found in extracts of renal inner medulla and to a lesser extent in the renal outer medulla and cortex of several mammalian species. Liver extracts were more active than other nonrenal tissues. Bacterial osmoprotective activity and concentration of glycine betaine in the renal inner medulla of rabbits were found to correlate closely with urinary osmolarity. Concentrations of sorbitol were found to be also increased in the renal inner medulla during osmotic stress, but this compound is not osmoprotective for E. coli. Glycine and proline betaine were recovered in urine of rabbits and were increased in those given high osmotic loads. Only small amounts of proline betaine were recovered in the renal inner medulla. The source from which proline betaine is derived is unknown.

Animals↗

Managing bibliographic citations using microcomputers.

Programs are now available to construct and retrieve lists of bibliographic citations by microcomputers. Although considerable effort must be expended to learn to use them, once mastered, they can be useful to anyone who must manage large collections of references. There are several ways to use personal computers to store and retrieve bibliographic citations. Word processors can be used to manage relatively small lists of citations. Preprogrammed bibliographic systems are available that are designed specifically for this purpose. A general data base management program can also be adapted for bibliographic purposes and used for other functions as well. This essay has been prepared to provide guidance to those who have a working knowledge of microcomputers and wish to expand this to use a data management system for bibliographic purposes. The dBASE II program is used to illustrate how to set up a bibliographic system. Methods are described on how to prepare citations for storage and retrieval using combinations of key words and Boolean operators, how to prepare selected lists of references and arrange them in alphabetic order or by subject heading, and how to print tailored lists of citations. The system was found to be highly responsive to commands and able to provide rapid retrieval of information.

Bibliography of Medicine↗

The responsibility of the infectious disease community for the optimal use of antimicrobial agents.

Antimicrobial agents are a critical element of the therapeutic armamentarium of modern medicine. How well they are used reflects our ability to treat and prevent infectious diseases. The major consideration for proper usage is to select the optimal agent at the proper dosage. Secondary, but important concerns are to minimize the emergence of resistance and to provide health services at a reasonable cost. The infectious disease community must work in concert with the pharmaceutical industry to achieve these goals. The relations of infectious disease physicians with the industry have been remarkably effective in evaluating and introducing new drugs, however, it is natural that conflicts should arise. Although the overall accomplishments have been outstanding, there is considerable evidence that antimicrobial agents are often abused and used excessively. This paper outlines some of the issues of marketing and the problems inherent in industry-sponsored trials. As specialties other than infectious diseases have encountered major difficulties, it is timely that this society adopts a code of ethical conduct for its work with industrial sponsors and takes the initiative in developing programs for education of other physicians in the field of infectious diseases and antimicrobial therapy both in this country and in developing nations.

Anti-Bacterial Agents↗

The osmoprotective properties of urine for bacteria: the protective effect of betaine and human urine against low pH and high concentrations of electrolytes, sugars, and urea.

Growth of Escherichia coli was inhibited in a defined minimal medium by high concentrations of electrolytes and sugars in direct relation to their osmotic strength. Choline, betaine, proline, and human urine increased resistance to these substances. In contrast, the toxic effect of urea was not altered directly by betaine or urine, but was reduced in the presence of other osmolytes. The osmolyte protective effect was augmented by betaine. The osmoprotective effect of betaine and urine was confirmed with 40 strains of enteric bacteria. Urine from 19 healthy subjects contained osmoprotective activity greater than that observed with betaine. A methanol extract of urine was found to be highly protective. Although betaine was present in the extract, it could not account for all the protective activity. Urine contains additional low-molecular-weight osmoprotective agents.

Anti-Bacterial Agents↗

Culture of the surfaces of urinary catheters to sample urethral flora and study the effect of antimicrobial therapy.

At the time indwelling urinary catheters were removed, the urethral flora was sampled by rolling the catheters onto culture plates. Cultures were obtained from 398 patients with sterile urine. Catheter surfaces were colonized less often in males than in females (16.8 and 67.0%, respectively) and yielded correspondingly fewer bacterial species per catheter. In both sexes, gram-positive species were isolated more frequently than gram-negative species (428 and 131 isolates, respectively). The bacteria most commonly isolated were Staphylococcus epidermidis and Streptococcus faecalis. Staphylococcus saprophyticus was not recovered despite the large proportion of young, sexually active women in the study population. Gram-negative bacteria, mainly Escherichia coli, gradually colonized the catheters over time but at all times were recovered in lower amounts the gram-positive organisms and less often in males than in females. Slime production by coagulase-negative staphylococci did not relate to the density of organisms recovered from the catheters or influence the presence of gram-negative bacteria. Despite frequent use of antibiotics in this population, the urethral flora remained highly susceptible to these drugs. Antibacterial activity was not detected on the catheters despite high concentrations in the urine. This suggests that systemic antibiotics have a very limited effect on resident urethral flora. Despite relatively small numbers in the urethra, gram-negative bacteria readily produce urinary tract infections in catheterized patients.

Adhesiveness↗

Does kidney infection cause renal failure?

Our current knowledge of the long-term outcome of uncomplicated urinary tract infections in women is based on several things: a reevaluation of the criteria for defining pyelonephritis at autopsy, careful description of the causes of renal disease among patients entering dialysis and transplant programs, long-term observation of patients, and epidemiologic studies attempting to determine the association of bacteriuria with mortality. The weight of the evidence favors the conclusion that, although urinary tract infections can severely impair renal function, this is rare in the absence of a major predisposing factor such as obstruction, calculus, reflux, abnormalities of the voiding mechanism, or diabetes. The predisposing lesions, however, may go undetected until heralded by episodes of acute pyelonephritis or by renal failure. Unfortunately, urinary tract infections are so common that it is difficult to distinguish the population at greatest risk. The possible role of renal damage produced by autoimmune mechanisms following infection needs continued study.

Adolescent↗

Genitourinary infections in the patient at risk: extrinsic risk factors.

The indwelling urinary catheter is an essential part of modern medical care. It is widely used to relieve temporarily anatomic or physiologic urinary obstruction, to facilitate surgical repair of the urethra and surrounding structures, to provide a dry environment for comatose or incontinent patients, and to permit accurate measurement of urinary output in severely ill patients. Unfortunately, when poorly managed, the indwelling catheter may present a hazard to the very patients it is designed to protect. It is the leading cause of nosocomial induced urinary tract infections and the most common prediposing factor in fatal gram-negative sepsis in hospitals. Catheters drain the bladder, but they obstruct the urethra, producing other major problems such as urethral strictures and epididymitis. Advances in catheter care since the introduction of closed drainage are reviewed. The best means of prevention is the avoidance of use when unnecessary and prompt removal when the need no longer exists. This practice is of particular importance in long-term care institutions. Alternate methods include intermittent catheterization in the paraplegic patient, condom drainage in the nonobstructed patient, and direct drainage of the bladder through the skin. Most recent studies have attempted to improve care of the indwelling catheter by either prevention of periurethral infection (the most common route of acquisition) or sterilization of the drainage bag to prevent ascending infection and cross infection. Thus far, these methods have been unsatisfactory. A new approach to designing drainage systems is clearly needed. Finally, all studies failed to demonstrate the ability of systemic antimicrobial therapy to eradicate catheter-associated infections other than temporarily. Instead, excessive use of antibiotics has led to the emergence of resistant strains that may be spread to other patients through contaminated urine.

Anti-Infective Agents, Urinary↗

The expert witness in medical malpractice litigation.

The experience of serving as an expert witness can add considerably to a physician's knowledge of medicine and the forces that affect the profession. Each case compels the physician to examine carefully all the clinical data. The physician must assess the quality of care given and render an opinion that is consistent with the facts and pertinent literature. He must defend his position under close questioning by an informed attorney aided by expert witnesses on the opposing side. This rigorous exercise requires considerable skill and experience. It has many of the characteristics of a well-conducted clinicopathological conference, with the added drama of the interplay of personalities. Despite the stimulating atmosphere, it is critical to maintain objectivity by asking yourself repeatedly, "What would I have done if placed in the same circumstance as the accused physician?" If you accept the responsibility of serving as an expert witness, it should be one of the best consultations you have ever given.

Attitude of Health Personnel↗