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Biomedical subjects

C M Kunin

Publications and source records attributed to C M Kunin.

At least 37 records · Page 2Linked to original sources

Postmortem microbiological findings of two total artificial heart recipients.

This report describes the postmortem microbiological findings and related gross pathology from two patients who had the longest survival after implantation of the Jarvik-7-100 total artificial heart. We documented extensive polymicrobial colonization at the site of the device and adjacent structures; however, the internal drive lines were remarkably free of bacterial colonization despite evidence of infection at the skin junction and in close proximity to the artificial heart. The polyurethane polymer (Biomer) on the external surface of the device was discolored and pitted in appearance and the Velcro material that attaches the two ventricles together was eroded. A nonspecific mass of tissue that was adherent to the device and to portions of the drive lines contained inflammatory cells, fibrinous debris, and colonies of microorganisms.

Autopsy

Infectious complications in four long-term recipients of the Jarvik-7 artificial heart.

This article describes the infectious complications that occurred among four of the longest-term recipients of the Jarvik-7 artificial heart. Infection arising from the drive lines, with spread to the mediastinal periprosthetic space, was the major limiting factor in long-term use of the device in these patients. Periprosthetic infections were due to coagulase-negative staphylococci, Staphylococcus aureus, Pseudomonas aeruginosa, and other Pseudomonas species. Other infectious complications incurred by some of the patients included pneumonia, empyema, urinary tract infection, and intravascular line sepsis with Candida. Intensive antimicrobial therapy for prolonged periods seemed to suppress but not to eradicate infection and was accompanied by the appearance of multiresistant bacterial strains. Complications of antimicrobial therapy included diarrhea secondary to overgrowth with Clostridium difficile in two patients. Use of the current device for more than 30 days should be considered extraordinary and should be reserved for patients for whom no other form of life support is available.

Adult

E pluribus unum.

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History, 20th Century

Indwelling urinary catheters in the elderly. Relation of "catheter life" to formation of encrustations in patients with and without blocked catheters.

In order to define the natural history of indwelling urinary catheters in the elderly, 50 patients aged 65 years or older were followed. Their catheters had been in place for a mean of 33.2 days. When removed, 40.4 percent were blocked or showed poor flow. After the catheters were changed, the 14-day "catheter life" was 78 percent. About half the population had blocked catheters. They had a 14-day "catheter life" of only 31.8 percent (p = less than 0.01). Patients with blocked catheters ("blockers") excreted more alkaline urine, calcium, protein, and mucin than patients without blocked catheters ("nonblockers"), but urea-splitting bacteria were no more frequent. The mortality was not significantly different. Flow of water through catheters was closely related to extent of encrustations. Encrustations formed uniformly throughout the catheter lumen except when the tip was obstructed. The distribution and number of species of microorganisms (three and a half per specimen) were virtually identical in catheter and bladder urine, but the counts in the catheter urine were more frequently greater than 100,000 cfu/ml (p = less than 0.01). Patients with blocked catheters appear to be metabolically different from patients without blocked catheters and should have their catheters changed at seven to 10 days to avoid obstruction.

Aged

Formation of encrustations on indwelling urinary catheters in the elderly: a comparison of different types of catheter materials in "blockers" and "nonblockers".

In order to determine the effect of catheter materials on formation of encrustations in long-term indwelling urinary catheters in the elderly we performed a crossover study utilizing commercially available silicone, silicone-coated, teflon-coated and latex catheters that were left in place for 14 days. The study was conducted with #18 french catheters fitted with a 30 ml. balloon since smaller size catheters frequently fell out spontaneously. The distinction between patients who were "blockers" and "nonblockers" was found to be clinically useful since "nonblockers", who constituted about half the population, did well regardless of type of catheter material used. Formation of encrustations and blockage was significantly less in "blockers" with silicone than with teflon-coated or latex catheters. The more rapid flow-time through silicone catheters appears to be related to a larger bore. Although this study supports the use of silicone catheters for "blockers" on long-term drainage the results should not be interpreted to imply that they are preferable to other types of catheters for short-term use or to changing less expensive catheters more frequently when needed.

Aged

Enteric colonization with antibiotic resistant bacteria in nurses working in intensive care units.

To determine whether nurses who worked in an intensive care unit (ICU) might acquire enteric colonization with Gram-negative aerobic bacteria from their patients, rectal swabs were obtained from the patients and nurses in the ICU, from nurses working in a coronary care unit (CCU) and from young women with urinary tract infection who had not been exposed to the hospital environment. The healthy women differed from the patients in that their enteric flora contained greater numbers of lactose fermenting bacteria, they were less often colonized by resistant organisms and when resistant bacteria were present they were less abundant than in the patients. Nurses who had been treated with antimicrobial agents during the preceding six months were colonized more often with antibiotic resistant enteric bacteria. There was no evidence of transmission of antibiotic resistant Escherichia coli from patients to nurses largely because this species had been virtually eliminated from the patients by intensive use of antimicrobial agents. Instead, several multiresistant species of Klebsiella, Citrobacter and Pseudomonas were isolated from the patients and ICU nurses. It was difficult, however, to define clearly patient-nurse controls who had no exposure to the ICU patients. These observations and those of other investigators emphasize the need for examination of control populations and of therapeutic use of antibiotics when examining the issue of environmental acquisition of antibiotic resistant bacteria.

Adolescent

Morbidity and mortality associated with indwelling urinary catheters in elderly patients in a nursing home--confounding due to the presence of associated diseases.

A prospective study was conducted in a nursing home among elderly residents treated with and without indwelling catheters. Most of the patients were white females with a mean age of 82.3 years. The mortality at 6 months among catheterized patients was 30.2% compared with 10.1% among the noncatheterized groups (P less than 0.001). Patients with catheters differed significantly from those without in having more impaired mental status and diminished activities of daily living. They also differed significantly for eight of 30 diseases. Cerebrovascular and hypertensive disease were significantly more common in catheterized patients. In contrast, fractures and musculoskeletal disorders were significantly more common among noncatheterized patients. Catheterized patients had significantly more days with fever and symptomatic urinary tract infections and received antibiotics more often than did noncatheterized patients. We conclude that: (1) direct comparisons of morbidity and mortality among catheterized and noncatheterized populations are not valid because of confounding by the presence of associated life-threatening illnesses; and (2) catheterized patients have more clinical episodes of urinary tract infections and fever and are treated more frequently with antibiotics.

Activities of Daily Living

Dimethylthetin can substitute for glycine betaine as an osmoprotectant molecule for Escherichia coli.

Glycine betaine is believed to be the most active naturally occurring osmoprotectant molecule for Escherichia coli and other bacteria. It is a dipolar ion possessing a quaternary ammonimum group and a carboxylic acid group. To examine the molecular requirements for osmoprotective activity, dimethylthetin was compared with glycine betaine. Dimethylthetin is identical to glycine betaine except for substitution of dimethyl sulfonium for the quaternary nitrogen group. Dimethylthetin was found to be about equally as effective as glycine betaine in permitting E. coli to grow in hypertonic NaCl, and both compounds were recovered almost completely from bacterial cells grown in the presence of hypertonic NaCl. 3-Dimethylsulfonioproprionate, an analog of dimethylthetin observed in marine algae, and 3-Dimethylsulfonio-2-methylproprionate were found to be less active. Dimethylthetin may prove useful as a molecular probe to study betaine metabolism and as a model for the development of antibacterial agents.

Betaine

Isolation of glycine betaine and proline betaine from human urine. Assessment of their role as osmoprotective agents for bacteria and the kidney.

Human urine is osmoprotective for enteric bacteria, permitting E. coli to grow with high concentrations of NaCl and other salts and even higher concentrations of sucrose and mannitol but not urea. The active material in urine is soluble in methanol and is precipitated by ammonium reineckate at acid pH. Using gel filtration and high-pressure liquid chromatography, we have identified two major osmoprotective compounds in urine. One is glycine betaine; the other is proline betaine as demonstrated by nuclear magnetic resonance, mass spectrum scanning, and chemical synthesis. Proline betaine has not been described previously to our knowledge in vertebrate tissues. It is known to be a cell volume-regulating agent for marine red algae and the euryhaline mollusk Elysia chloritica. We suggest that the presence of glycine and proline betaines in human urine may reflect an osmoprotective role for the kidney and that they protect bacteria in the urine only fortuitously.

Betaine

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