PubMed Health⌕ Search

Biomedical subjects

S P Cohen

Publications and source records attributed to S P Cohen.

17 recordsLinked to original sources
PubMed1991

Early catheter removal vs. conventional practice in patients undergoing transurethral resection of prostate.

A retrospective analysis of 127 of 146 consecutive patients undergoing transurethral resection of the prostate from February 1985 to January 1988 (3-year period) was performed. The catheter was removed on postoperative day 1 in 66 patients (group I) and on postoperative day 2 in 61 patients (group II). There were no significant differences between the two groups in terms of population age, weight of resected glands, operative time, and management. Both groups I and II had 8 complications following catheter removal. Postoperative hospital stay was reduced by an average of 1.37 days in group I. Total hospital cost was reduced by approximately $466.00. We conclude that catheter removal on postoperative day 1 is safe with no added morbidity while having the advantage of reduced hospital costs.

Aged↗
PubMed1991

marA, a regulated locus which controls expression of chromosomal multiple antibiotic resistance in Escherichia coli.

Stable chromosomal multiple-antibiotic-resistant (Mar) mutants of Escherichia coli, derived by exposing susceptible cells to low concentrations of tetracycline or chloramphenicol, express cross-resistance to structurally unrelated antibiotics. The entire resistance phenotype is reversed to susceptibility by insertion of transposon Tn5 into a locus, designated marA, near 34 min on the chromosome (A. M. George and S. B. Levy, J. Bacteriol. 155:541-548, 1983). Strains in which 39 kbp of chromosomal DNA, including marA, had been deleted were unable to produce Mar mutants. The deletion strain could be complemented in trans by introduction of intact marA+ on plasmid F'506. Junction fragments from a strain containing marA::Tn5 were cloned, exploiting kanamycin resistance on Tn5 for selection. They were used as probes to search a phasmid library of E. coli K-12 for recombinants containing the marA+ region. Two phasmids which contained regions hybridizing to this probe were identified and shown to complement delta marA in a deletion strain. From one phasmid, several marA-containing fragments were cloned: those of greater than or equal to 7.8 kbp restored the ability to form Mar mutants in a deletion strain. These Mar mutants were shown to be dependent on the cloned marA fragment. Chromosomal as well as recombinant Mar mutants showed increased expression of a marA-specific mRNA species of about 1.4 kb, which was barely or not detectable in wild-type strains. Exposure of mutants and, to a lesser extent, parental strains to tetracycline or chloramphenicol resulted in elevated levels of mRNA which hybridized to the marA probe. These results indicate that the marA locus is needed for production of Mar mutants and is regulated, responding to at least two antibiotics to which it controls resistance.

Autoradiography↗
PubMed1991

Suffering and euthanasia.

Suffering is a powerful but elusive concept in veterinary medicine. Because the companion animal cannot talk, assessment of suffering requires the best judgment of veterinarian, family, and other interested participants. Determining whether euthanasia is appropriate rests on a similar consensus but is based on the entire medical and social situation. Clinicians need skill, sensitivity, and a well-developed sense of timing to uncover what clients really feel and want. Offering the family options, such as to be present during the euthanasia, makes the veterinarian's task easier and helps clients cope.

Animals↗
PubMed1989

Cross-resistance to fluoroquinolones in multiple-antibiotic-resistant (Mar) Escherichia coli selected by tetracycline or chloramphenicol: decreased drug accumulation associated with membrane changes in addition to OmpF reduction.

Chromosomal multiple-antibiotic-resistant (Mar) mutants of Escherichia coli, selected on agar containing low concentrations of tetracycline or chloramphenicol, were 6- to 18-fold less susceptible to the fluoroquinolones than were their wild-type E. coli K-12 or E. coli C parental strains. The frequency of emergence of such mutants was at least 1,000-fold higher than that of those selected by the fluoroquinolone norfloxacin directly. When Mar mutants, but not wild-type cells, were plated on norfloxacin, mutants resistant to high levels of norfloxacin (2 micrograms/ml) appeared at a relatively high (approximately 10(-7] frequency. In addition to decreased amounts of OmpF, Mar mutants had other outer membrane protein changes and were four- to eightfold less susceptible to fluoroquinolones than was an ompF::Tn5 mutant lacking only OmpF. Accumulation of [3H]norfloxacin was more than threefold lower in the Mar mutants than in wild-type cells and twofold lower than in the OmpF-deficient derivative. These differences were not attributable to a change in the endogenous active efflux system for norfloxacin in E. coli. Norfloxacin-induced inhibition of DNA synthesis was threefold lower in intact cells of a Mar mutant than in susceptible cells, but this difference was not seen in toluene-permeabilized cells. Insertion of Tn5 into marA (min 34.05 on the chromosome) led to a return of the wild-type patterns of norfloxacin accumulation, fluoroquinolone and other antimicrobial agent susceptibilities, and outer membrane protein profile, including partial restoration of OmpF. These findings together suggest that marA-dependent fluoroquinolone resistance is linked to decreased cell permeability, only part of which can be accounted for by the reduction in OmpF. Once mutated to marA, cells can achieve high levels of quinolone resistance at a relatively high frequency.

Anti-Infective Agents↗
PubMed1988

Endogenous active efflux of norfloxacin in susceptible Escherichia coli.

Escherichia coli was shown to have an energy-dependent reduced uptake of the fluoroquinolone antimicrobial agent norfloxacin. Studies of everted inner membrane vesicles suggested that this reduced accumulation involved a carrier-mediated norfloxacin active efflux generated by proton motive force with an apparent Km of 0.2 mM and a Vmax of 3 nmol min-1 mg of protein-1. Other hydrophilic, but not hydrophobic, quinolones competed with norfloxacin for transport. Porin (OmpF)-deficient E. coli cells were twofold less susceptible to norfloxacin and showed twice as much energy-dependent reduction in drug uptake. However, active efflux assayed in everted vesicles from the OmpF strain was unchanged compared with that in the parental strain. These findings suggest that in the OmpF mutant decreased outer membrane permeability, combined with active efflux across the inner membrane, in some manner results in decreased steady-state uptake of norfloxacin and lowered drug susceptibility.

Anti-Infective Agents↗
PubMed1988

marA locus causes decreased expression of OmpF porin in multiple-antibiotic-resistant (Mar) mutants of Escherichia coli.

Mar (multiple antibiotic resistant) mutants of Escherichia coli express chromosomally mediated resistance to a variety of structurally unrelated hydrophilic and hydrophobic antibiotics. Insertion of transposon Tn5 into the marA locus at min 34.05 on the chromosome completely reverses the Mar phenotype (A. M. George and S. B. Levy, J. Bacteriol. 155:531-540, 1983). We found that among changes in the outer membrane of Mar mutants, porin OmpF was greatly reduced, although Mar mutants were more resistant than cells lacking only OmpF. Transduction of the marA region from a Mar strain, but not a wild-type strain, led to loss of OmpF. P1 transduction of marA::Tn5 into a Mar mutant partially restored OmpF levels. Therefore, OmpF reduction required a mutation in the marA region. Mar mutants of an ompF-lacZ operon fusion strain expressed 50 to 75% of the beta-galactosidase activity of the isogenic non-Mar parental strain, while Mar mutants of a protein fusion strain expressed less than 10% of the enzyme activity in the non-Mar strain. These changes were completely reversed by insertion of marA::Tn5. The responsiveness of OmpF-LacZ to osmolarity and temperature changes was similar in Mar and wild-type strains. Although some transcriptional control may have been present, OmpF reduction appeared to occur primarily by a posttranscriptional mechanism. The steady-state levels of ompF mRNA were twofold lower and the mRNA was five times less stable in the Mar mutant than in the wild-type strain. Expression of micF, which lowers ompF mRNA levels, was elevated in Mar strains, as revealed by a micF-lacZ fusion. Studies with strains deleted for the micF locus showed that the marA-dependent reduction of OmpF required an intact micF locus. Our findings suggest that the marA locus directly or indirectly increases micF expression, causing a posttranscriptional decrease in ompF mRNA and reduced amounts of OmpF.

Bacterial Outer Membrane Proteins↗
PubMed1987

Phenylmethylsulfonyl fluoride (PMSF) inhibits 17 beta-estradiol binding to estrogen receptor from human prostate.

Estrogen receptor binding studies were performed on cytosol obtained from human benign prostatic hyperplasia (BPH) tissue. Binding assays were done in the absence or presence of various concentrations of phenylmethylsulfonyl fluoride (PMSF). Saturation analysis and Scatchard plots showed that the binding of 17 beta -estradiol to the estrogen receptor (ER) was inhibited by PMSF. The nature of the inhibition appears to be uncompetitive, as determined from double-reciprocal plots. Glycerol density gradient centrifugation analysis also confirmed the results obtained with Scatchard plots. The inhibition observed in the presence of dithiothreitol (DTT) was greater than the inhibition observed in the absence of DTT. The maximum number of binding sites (Bmax) observed in our present study was 59.1 +/- 34.1 fmol/mg protein with an equilibrium dissociation constant (KD) of 2.2 +/- 2.2 nM. Our study indicates that PMSF significantly affects 17 beta -estradiol binding to ER and consequently alters the estimation of ER in Human BPH.

Centrifugation, Density Gradient↗
PubMed1987

High tech-soft touch: breastfeeding issues.

Hospital practices and staff interactions need to be reviewed carefully in each institution and community to examine the direct or indirect effects on human lactation and breastfeeding. With the increased incidence of breastfeeding and the continued promotion by the Surgeon General and the American Academy of Pediatrics, it is imperative that health care professionals examine the attitudes that affect their behavior as they interact with their patients about lactation. The high-tech routines must be altered to facilitate the normal aspects of the breastfeeding process. A mother must be close to learn how to interact with and touch her new infant. The greatest challenge is not in changing the written policies nor the curtains or surroundings but in changing the attitudes and beliefs of the staff, so that human lactation and breastfeeding are treated as normal physiologic, psychological, and nurturing activities of mothers and infants.

Adult↗
PubMed1985

The role of social work in a veterinary hospital setting.

Social workers can assist veterinarians and their clients in dealing with such difficult situations as euthanasia decisions, grief reactions, and professional stress. They are already at work at The Animal Medical Center, where they counsel clients individually and in groups, consult with veterinarians on client relations and how to cope with their own stress, and develop educational programs for employees and others.

Animals↗
PubMed1977

Renal carbuncle: the use of ultrasound in its diagnosis and treatment.

The use of ultrasound in the diagnostic and therapeutic management of 5 patients with renal abscesses is described. A spectrum of ultrasonic findings was noted, with the majority of the lesions being anechoic (3 cases). However, a few lesions showed a mixed pattern (2 cases). Ultrasonic aspiration of abscess fluid for culture and sensitivity obviated an operation in 1 case. For the first time, ultrasonically guided, percutaneous, indwelling catheter drainage of a renal carbuncle is reported. Since the patient had failed to respond to systemic antibiotic therapy this technique saved the patient from undergoing an operation. The clinical and ultrasonic findings in the 6 previous case reports of abscesses are reviewed.

Abscess↗
PubMed1975

Spontaneous expulsion of intravesical bullet.

The first reported case of spontaneous expulsion per urethra of an intravesical bullet which initially entered through the left flank is presented. Recognition of the truc location of the millile might have been facilitated had lateral and/or oblique films have been obtained under emergency conditions as advocated by the authors.

Abdominal Injuries↗