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Biomedical subjects

R Kessler

Publications and source records attributed to R Kessler.

At least 181 records · Page 10Linked to original sources
PubMed1988

Five-year followup of the Scott inflatable penile prosthesis and comparison with semirigid penile prosthesis.

The Scott inflatable penile prosthesis remains one of the most popular devices available for the surgical treatment of impotence despite high complication and reoperation rates. We present our 5-year followup of 116 inflatable prostheses placed before 1981 in 85 patients, with a 61 per cent overall 5-year complication rate. The incidence of complications by year after operation showed that most (22 per cent) devices failed within 1 year after implantation, with failure rates gradually decreasing to 6 and 7 per cent during years 4 and 5, respectively. Of 85 patients receiving an inflatable prosthesis 61 per cent underwent reoperation during the 5-year followup. A 5-year overall complication rate of only 14 per cent was seen in 29 Small-Carrion semirigid prostheses implanted during the same time. The results of numerous recent improvements in the design and structure of the Scott inflatable penile prosthesis to prevent mechanical device failure remain to be tested over the long term.

Adult↗
PubMed1988

Infectious complications of penile prosthesis surgery.

Penile prosthetic surgery has become an increasingly common procedure. However, infection of the prosthesis remains a significant complication that almost always results in loss of the device. We present our 10-year experience with 9 infected prostheses among 417 total penile implants, for an over-all incidence of infectious complications of 2.2 per cent. A strict, broad-spectrum antibiotic schedule was adhered to rigidly by all patients, beginning preoperatively and continuing for a total of 10 days of perioperative coverage. Staphylococcus species were cultured in 56 per cent of the infected patients and in 100 per cent of the patients with positive cultures. Spinal cord injury patients showed a particular predisposition to prosthetic infection, with a 15 per cent incidence of infectious complications. Two other patients became infected after dental procedures and the need for routine antibiotic prophylaxis in the penile prosthesis patient is emphasized. Urinary tract instrumentation at the time of prosthetic implantation, whether planned or incidental, also appears to add a potentially avoidable risk for subsequent infection.

Adult↗
PubMed1988

An examination of O-2-isocephems as orally absorbable antibiotics.

The synthesis and structure-activity relationships of a series of orally absorbed O-2-isocephems are described. These compounds possessed a D-[(p-hydroxyphenyl)glycyl]amino substituent at the 7-position while the substituent at the 3-position was varied. Relative to the analogous cephems, the O-2-isocephems exhibited comparable to better activity against Gram-positive organisms. Against Gram-negative organisms, their activity was variable but did indicate a lower beta-lactamase stability. Following oral administration, the O-2-isocephems generally exhibited longer half-lives but lower Cmax's and urinary recoveries.

Administration, Oral↗
PubMed1988

Binding of fructose 2,6-bisphosphate to yeast phosphofructokinase.

Binding of Fru-2,6-P2 to yeast phosphofructokinase was investigated by ultrafiltration technique. Per mol of subunit of phosphofructokinase (M = 100,000) 0.5 moles of Fru-2,6-P2 are bound. The binding curve proceeds cooperatively (nH = 1.8 +/- 0.2). The apparent affinity constant of Fru-2,6-P2 amounts to about 2.25 +/- 0.12 microM. Fru-1,6-P2 decreases the affinity of yeast phosphofructokinase to Fru-2,6-P2. The data can be described by assuming either competition of Fru-2,6-P2 and Fru-1,6-P2 for the same binding site or conformationally mediated interactions.

Fructosediphosphates↗
PubMed1988

[Hypoxia and pulmonary circulation. The importance of hypoxia in pulmonary arterial hypertension of chronic obstructive bronchopneumopathies].

In chronic airflow obstruction (CAO), there are grounds for distinguishing between the effects of acute alveolar hypoxia and those of chronic hypoxia. Acute hypoxia leads, in healthy subjects, to pulmonary vasoconstriction. In patients with CAO, there is however a great variability in the pulmonary vascular response to hypoxia. Chronic hypoxia leads in the long term to structural modifications in the pulmonary vessels (arteriolar muscularization, hypertrophy of the small arterial muscles, and intimal fibrosis), which are similar enough to those seen in residents at high altitude and which lead to an elevation of the pulmonary vascular resistance. These structural changes are potentially reversible but one does not know up to which point they are. This potential reversibility represents one of the justifications of long term oxygen therapy in these patients. The pulmonary arterial hypertension of CAO is generally moderated; it evolves slowly over years and years in the majority of cases; it certainly doesn't merit to be treated at any cost. Up to the present, pulmonary vasodilators have given rather disappointing results. Prolonged oxygen therapy (for greater than 16 hours in 24), which improves in other respects the expectation of life in patients is currently the most logical treatment for pulmonary hypertension in CAO.

Humans↗
PubMed1987

Fructose-2,6-bisphosphatase and 6-phosphofructo-2-kinase are separable in yeast.

Fructose-2,6-bisphosphatase was purified from yeast and separated from 6-phosphofructo-2-kinase and alkaline phosphatase. The enzyme released Pi from the 2-position of fructose 2,6-bisphosphate and formed fructose 6-phosphate in stoichiometric amounts. The enzyme displays hyperbolic kinetics towards fructose 2,6-bisphosphate, with a Km value of 0.3 microM. It is strongly inhibited by fructose 6-phosphate. The inhibition is counteracted by L-glycerol 3-phosphate. Phosphorylation of the enzyme by cyclic-AMP-dependent protein kinase causes inactivation, which is reversible by the action of protein phosphatase 2A.

Chromatography, Affinity↗
PubMed1987

Positron emission tomography studies of basal ganglia and somatosensory cortex neuroleptic drug effects: differences between normal controls and schizophrenic patients.

Glucose metabolic rate in the basal ganglia, thalamus, and somatosensory cortex was examined in eight patients with schizophrenia before and after receiving neuroleptic medication. Basal ganglia metabolic rates were increased with medication: more on the right than on the left and more in putamen than caudate. The cortical anteroposterior ratio, an index of relative hypofrontality, was not affected by neuroleptics. The brain areas that were found to be altered by neuroleptics were selected for comparison between off-medication schizophrenics and controls. Metabolic rates in the basal ganglia tended to be low in patients with schizophrenia in comparison to 24 age- and sex-matched controls.

Adolescent↗
PubMed1987

Vasectomy and vasovasostomy have no effect on seminal plasma zinc concentrations.

Mean zinc concentrations were determined for human seminal plasma obtained from 110 nonvasectomized men (139 micrograms. per ml.), 43 recently vasectomized men (144 micrograms. per ml.), 25 long-term vasectomized men (139 micrograms. per ml.) and 25 men who had undergone vasovasostomy (129 micrograms. per ml.). The results indicate that there is no significant short-term or long-term effect of these surgical procedures on prostatic secretory function as measured by seminal plasma zinc concentration.

Humans↗
PubMed1986

Hemorrhoids or rectal varices: defining the cause of massive rectal hemorrhage in patients with portal hypertension.

Identifying the source of lower gastrointestinal hemorrhage in patients with chronic liver disease and portal hypertension can be challenging. We present 2 cases of hemorrhage from rectal varices and a discussion on the differences between simple hemorrhoids and rectal varices. Evaluation of rectal bleeding in patients with portal hypertension is discussed and possible therapeutic options are described.

Adult↗
PubMed1986

Internal urethrotomy in girls and its impact on the urethral intrinsic and extrinsic continence mechanisms.

The cause of incontinence in a group of 11 girls (mean age 18 +/- 3 years) who had undergone internal urethrotomy during childhood was assessed. Urodynamic methods were used to characterize the detrusor, and urethral profiles were performed to identify the impact of the operation on the extrinsic and intrinsic mechanisms of urethral closure. The results show that 4 of 11 patients demonstrated detrusor instability associated with a high voiding flow rate. The average resting urethral closure pressure in all patients showed significant reduction in maximum closure pressure (62 +/- 32 cm. water) when compared to normal age-matched controls. Transmission pressures to coughing demonstrated a high percentage of transmission to the distal and mid urethra (180 +/- 20 per cent). It was concluded that the intrinsic mechanism of urethral continence as measured by the resting urethral pressure profile was compromised by the urethrotomy. However, the extrinsic mechanisms as measured by the transmission values was not affected. On the basis of these findings it is argued that internal urethrotomy compromises the closure mechanisms intrinsic to the urethra. Continence in these patients most likely is maintained by the action of extrinsic factors transmitting high closure pressures at the distal third of the urethra. Finally, it is postulated that urethrotomy patients are at increased risk for stress incontinence at an early age.

Adolescent↗
PubMed1986

Binding of fructose-1,6-bisphosphate to yeast phosphofructokinase.

Binding of fructose-1,6-bisphosphate to yeast phosphofructokinase (EC 2.7.1.11) was measured in a concentration range of 5 to 200 microM of fructose-1,6-bisphosphate with the ultrafiltration technique. At saturation two molecules of fructose-1,6-bisphosphate are bound per subunit of the octameric enzyme. Two distinct types of binding sites have been observed. The high affinity sites (KH = 32.7 +/- 5 microM) exhibit a hyperbolic response in respect to the binding of fructose-1,6-bisphosphate, the low affinity sites (KL = 57.2 +/- 6 microM) show significant positive cooperativity.

Fructosediphosphates↗
PubMed1985

The statistical interaction of cerebral specialization and integration in the interpretation of dynamic brain images.

Two constructs of brain function, namely cerebral specialization and integration, have been examined in the analysis of blood flow and metabolic function resulting from dynamic imaging procedures. The purpose of the current paper is to illustrate the interaction of these two constructs at the statistical level. Because of the statistical interaction, it is argued that the currently accepted statistical evidence for cerebral specialization is, in fact, partially a function of the degree of regional cerebral integration. Therefore, found asymmetries of flow or rate may be solely a function of cerebral integration. These points are discussed with respect to developing a better understanding of stimulus/brain/behavior relations.

Blood Glucose↗
PubMed1985

Alternative statistical models for the examination of clinical positron emission tomography/fluorodeoxyglucose data.

This article describes a method for partitioning metabolic variability found in positron emission tomography/[18F]fluorodeoxyglucose studies. For the 15 subjects examined, 74.8% of the total metabolic variability could be ascribed to individual differences in global metabolic rate, whereas 15.8% of the total variability was consistent regional variation or pattern across subjects. Subsequently, the method of Q-component analysis is described for the identification of strong- and weak-pattern subjects. In addition, a standardization procedure that amplifies the observed pattern by removing systematic individual differences is described. Finally, the implications of these findings and methods for future and clinical studies are discussed.

Adolescent↗