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Biomedical subjects

S J Cohen

Publications and source records attributed to S J Cohen.

At least 19 recordsLinked to original sources
PubMed1992

Binding of Plasmodium falciparum 175-kilodalton erythrocyte binding antigen and invasion of murine erythrocytes requires N-acetylneuraminic acid but not its O-acetylated form.

Sialic acid on human erythrocytes is involved in invasion by the human malaria parasite, Plasmodium falciparum. Mouse erythrocytes were used as a reagent to explore the question of whether erythrocyte sialic acid functions as a nonspecific negative charge or whether the sialic acid is a necessary structural part of the receptor for merozoites. Human erythrocytes contain N-acetylneuraminic acid (Neu5Ac), whereas mouse erythrocytes, which are also invaded by P. falciparum merozoites, contain 9-O-acetyl-N-acetylneuraminic acid (Neu5,9Ac2) and N-glycoloylneuraminic acid (Neu5Gc), in addition to Neu5Ac. We compared the effects of sialidase and influenza C virus esterase treatments of mouse erythrocytes on invasion and the binding of a 175-kDa P. falciparum protein (EBA-175), a sialic acid-dependent malaria ligand implicated in the invasion process. Sialidase-treated mouse erythrocytes were refractory to invasion by P. falciparum merozoites and failed to bind EBA-175. Influenza C virus esterase, which converts Neu5,9Ac2 to Neu5Ac, increased both invasion efficiency and EBA-175 binding to mouse erythrocytes. Thus, the parasite and EBA-175 discriminate between Neu5Ac and Neu5,9Ac2, that is, the C-9 acetyl group interferes with EBA-175 binding and invasion by P. falciparum merozoites. This indicates that sialic acid is part of a receptor for invasion.

Animals↗
PubMed1992

The usefulness of matched pair randomization for medical practice-based research.

To be feasible, study designs for most intervention research in primary care settings must limit the number of participating physicians, without sacrificing the statistical power required to test the research hypotheses. A model was developed to examine sample size and statistical power requirements when using the physicians' practice as the unit of analysis. Randomized designs using either matched or unmatched samples of practices were compared under varying conditions. When baseline variability is small or the number of practice pairs is large, matching at best marginally increases power. However, in the typical case when baseline variability is large or the number of practice pairs is small, matching substantially increases the power to find intervention effects with a smaller sample. Thus, matching prior to randomization could improve the design of many intervention studies in primary care settings.

Humans↗
PubMed1992

Determinants of the in vitro interaction of polyaspartic acid and aminoglycoside antibiotics.

The in vitro interaction of polyaspartic acid (PAA) with aminoglycosides was evaluated using double diffusion in agar, dialysis chambers and changes in the optical density of test solutions. The results document a reversible, presumably electrostatic interaction that is optimized at a pH of approximately 5.0, by the absence of proteins over 800 Da, and at a 20:1 or 10:1 molar ratio of aminoglycoside to PAA. The PAA-aminoglycoside complex lost antibacterial activity and the ability to inhibit pronase E enzymatic activity. These results allow generation of a hypothesis as to the mechanism whereby PAA prevents aminoglycoside experimental nephrotoxicity.

Aminoglycosides↗
PubMed1991

Clinical trials in cancer therapy: efforts to improve patient enrollment by community oncologists.

A prerequisite for the completion of a clinical trial is the accrual of adequate numbers of patients. It is estimated that over 90-95% of all cancer patients are now treated in their local communities by practicing oncologists and are not seen by primary investigators at teaching hospitals. One risk of this trend is decreased patient enrollment into clinical trials. The private practitioner often lacks the academic oncologist's incentives to participate in clinical research. The Hoosier Oncology Group (HOG) is composed of community medical and radiation oncologists (85%) and Indiana University faculty members (15%). In an effort to improve patient enrollment onto clinical cancer research trials, HOG has attempted to identify 1) the major obstacles to patient enrollment by community oncologists and 2) potential aids to overcome such obstacles. One hundred fourteen members were surveyed and 75 responded (66%). The major obstacles were, in descending order: time demands on both the oncologist and his staff; explaining clinical trials to patients; completing flow sheets; perceived increased cost to the patient; remembering protocols; adhering to a rigid protocol. Aids identified as potentially most helpful were, in descending order: pocket-sized synopses of protocols; computer generated, individualized prompts; the availability of a clinical trials specialist to explain the clinical trial to patients and assist in obtaining informed consent; the availability of a video tape which could be used to explain clinical trials to patients. These aids are being implemented with the attempt to systemically study their impact on patient accrual.

Clinical Trials as Topic↗
PubMed1991

Cutaneous manifestations of cryoglobulinemia: clinical and histopathologic study of seventy-two patients.

In the 72 cases of cryoglobulinemia reviewed, erythematous to purpuric macules or papules were present in 92%. Infarction, hemorrhagic crusts, and ulcers were present in 10% to 25% of the patients and were relatively more common in type I cryoglobulinemia than in the other types. Postinflammatory hyperpigmentation was noted in 40%. Lesions on the leg were common in all types of cryoglobulinemia; however, lesions on the head and mucosal surfaces suggested type I cryoglobulinemia. Histopathologic features were classified as vasculitis in 50%, inflammatory or noninflammatory purpura in 15%, noninflammatory hyaline thrombosis in 10%, and postinflammatory sequelae in 10%. Noninflammatory hyaline thrombosis was relatively more frequent in type I. Thus erythematous to purpuric lesions on the legs and leukocytoclastic vasculitis are the common cutaneous findings in cryoglobulinemia. Type I cryoglobulinemia is suggested by noninflammatory hyaline thrombosis, cutaneous infarction, hemorrhagic crusts, skin ulcerations, and lesions of the head and neck and of oral or nasal mucosa.

Adult↗
PubMed1991

The effect of a household partner and home urine monitoring on adherence to a sodium restricted diet.

To evaluate the effects of social support and home urine monitoring on success with dietary sodium reduction, 114 essential hypertensive adults and a household partner were recruited. One of the pair was required to be the food preparer. Patients with their partners were randomly assigned to either an active or passive partner condition. During dietary counseling in the active condition, both patient and partner were involved in instructions to change their diet to reduce their daily sodium intake to 80 mmol or less. In the passive condition, the partners were present during the dietary counseling, but no effort was made to involve them directly in the instruction or to encourage them to make personal dietary changes. Patients and active partners collected two 24-hr urine collections between each of the first two counseling sessions and received feedback on the sodium results by a telephone call. In the passive partner condition, only patients collected urine for feedback. At the end of the 6 week instructional period, all patients and partners collected a 24-hr urine and had their blood pressure assessed. Half of each group was also randomly assigned to have access to a system for periodic home-monitoring of urine for sodium content during a 3-month period beginning at week 6 of the study (immediate). The delayed feedback group received the home-monitoring three months after completion of the dietary instruction. All patients, but only active partners, used the feedback system during their assignment periods and collected a 24-hr urine monthly between 6 and 30 weeks of the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Diet, Sodium-Restricted↗
PubMed1991

Nerve blocks for cutaneous surgery on the foot.

Anesthesia for cutaneous surgery on the foot is often achieved by local infiltration. However, procedures that involve large surface areas are anesthetized more effectively with peripheral nerve blocks. This discussion of peripheral nerve blocks for the feet includes an overview of the relevant sensory innervation, a brief discussion of local anesthetics, a description of the techniques, and representative cases.

Adult↗
PubMed1990

Establishing smoking cessation programs in dental offices.

Cigarette smoking is the leading cause of preventable death and disease in the United States. Because dental personnel treat millions of patients who are cigarette smokers, they have a unique opportunity to help persons quit the smoking habit. Effectively designed, office-based programs should involve all or most dental team members and contain the following components: a procedure that identifies smokers and records changes in their smoking status, a personal evaluation of each smoker's motivation to quit, an assessment of the degree of nicotine dependence experienced by potential quitters, the prescription of nicotine polacrilex therapy for appropriate candidates, personalized counseling commensurate with each patient's level of quitting readiness and, an effective system that ensures consistent patient follow-up and support.

Behavior Therapy↗
PubMed1990

Ureterocoeles.

Explore the source record for details and available documents.

Child↗
PubMed1989

Encouraging primary care physicians to help smokers quit. A randomized, controlled trial.

STUDY OBJECTIVE: To increase the effect that primary care physicians have on their patients who smoke. DESIGN: Randomized, controlled trial with 112 general internists and their patients who smoke. PATIENTS: Sample of 1420 patients from a general medicine clinic of a city-county teaching hospital, who smoke at least one cigarette a day and were recruited regardless of their interest in quitting smoking. INTERVENTIONS: Physicians were randomly assigned to one of four groups: participants who received a protocol for smoking management and a lecture on the consequences and management of smoking (control); in addition, had nicotine gum freely available to patients (gum); had stickers attached to their smokers' charts (reminder); or had both gum and reminders (both). MEASUREMENTS AND MAIN RESULTS: The percentage of patients with a return visit at 6 months who quit smoking (alveolar carbon monoxide of less than nine parts per million) was 1.3% (control), 7.7% (gum), 7.0% (reminders), and 6.3% (both). At 1 year the percentages were 2.7%, 8.8%, 15.0%, and 9.6%, respectively. Subsequent pairwise comparisons showed that the three intervention groups were not significantly different, but that each was significantly different from the control group (P less than 0.05). Physicians in all three intervention groups spent significantly more time than did the physicians in the control group counseling their patients about smoking. CONCLUSIONS: The availability of nicotine gum or labeling the charts of smokers can help primary care physicians increase their success rates two- to six-fold in helping patients quit smoking. If all primary care physicians used these procedures, they could help an additional 2 million smokers quit.

Adult↗
PubMed1989

Reconstruction of foreskin in distal hypospadias repair.

In the period between 1980 and 1985 101 one-stage repairs for distal hypospadias were carried out. Fifty-five patients were operated on using the Magpi technique as originally described by Duckett (1981). The hypospadias of the remaining 46 patients were corrected using a modification of this technique incorporating reconstruction of the foreskin. The technique of the modified, prepuce-preserving operation is described. Despite complications such as moderate meatal stenosis, fistulae and glandular-meatal as well as foreskin dehiscence, the overall functional and cosmetic results were very good.

Humans↗
PubMed1989

Anterior pelvic osteotomy. A new operative technique facilitating primary bladder exstrophy closure.

Posterior iliac osteotomy is a recognised method employed to facilitate and support anterior abdominal wall closure in patients with bladder exstrophy, but it adds considerably to the already lengthy procedure of bladder exstrophy surgery. Anterior pelvic osteotomy of the superior ramus of the pubic bone was developed to overcome this problem and to achieve a stable anterior pelvic ring with tension-free soft tissue closure. It can easily be performed after completing the bladder closure, without the need to turn the patient.

Bladder Exstrophy↗
PubMed1989

Neonatal urological ultrasound: diagnostic inaccuracies and pitfalls.

Ninety one patients with urinary tract abnormalities diagnosed before birth were reviewed. Diagnoses based on prenatal and postnatal ultrasound scans alone were compared with the final diagnoses after full urological investigations, with operative or necropsy confirmation in 79 cases. The results confirmed that ultrasound examination before birth usually detects nonspecific abnormalities and although scanning after birth is more accurate it is not absolutely reliable. A diagnosis of "multicystic kidney' made on ultrasound scan alone is especially prone to error. Such mistakes can be avoided if full urological investigation is undertaken in every case.

Diagnosis, Differential↗
PubMed1989

Helping smokers quit: a randomized controlled trial with private practice dentists.

Fifty private practitioners and their office staff members were randomly assigned to one of four groups: participants received a protocol for smoking management and a lecture on the consequences and management of smoking, or in addition, had nicotine gum freely available to patients, had stickers attached to their charts, or had gum and reminders. The percentage of patients in each group who had quit smoking a year later was 7.7, 16.3, 8.6, and 16.9, respectively, indicating a significant main effect for the gum conditions. The availability of nicotine gum also significantly increased the amount of time that patients reported they received smoking cessation counseling from the dentists and office staff.

Adult↗
PubMed1988

Heritable aspects of salt sensitivity.

Dietary salt reduction is an important nonpharmacologic remedy for mild hypertension as well as a useful adjunct to drug treatment. However, a reduced salt intake diet is not effective in reducing the blood pressure of all hypertensive patients. Several lines of evidence indicate that some patients are salt-sensitive whereas others are salt-resistant. A series of investigations have been conducted showing that the blood pressure responses to either acute salt and volume loading or to a reduced dietary salt intake are normally distributed. Blood pressure, humoral regulators of blood pressure and renal sodium handling are each found to be influenced by genetic variance. The change in blood pressure from dietary salt reduction is influenced by genetic variance as well. Definitions of salt sensitivity and resistance were formulated, and salt sensitivity of blood pressure was found to occur significantly more often in black than in white Americans. Furthermore, preliminary data suggest that measurement of phenotypes of haptoglobin in blood may assist in identifying salt-sensitive and salt-resistant subjects. Trials of a reduced salt intake diet in pharmacologically treated hypertensive patients are currently being conducted. The data suggest that at least half of the patients are salt-sensitive and that their medications may be reduced in response to the intervention. Results of this study may be of relevance to many of the 60 million Americans with hypertension, particularly to those who are black and elderly.

Adult↗
PubMed1988

Dietary sodium restriction as adjunctive treatment of hypertension.

To examine the effect of modest dietary sodium ion restriction in treated hypertensive individuals, we studied 114 hypertensive patients undergoing individualized dietary counseling with a research dietitian to achieve reduction in dietary sodium ion intake. A significant reduction in mean sodium ion intake was achieved after the first of three lessons and was maintained for 30 weeks with no change in potassium ion intake. Significant falls in blood pressure and body weight were observed with no significant correlations noted between the two variables, implying independence of these effects. Individuals compliant with the dietary sodium ion restriction goal (urinary excretion, less than or equal to 80 mmol/d [less than or equal to 80 mEq/24 h]) were more likely to have a reduction in number of medications than those not reaching that goal. Ninety-eight of the 114 patients completed the entire 30 weeks. Patients who dropped out tended to have lower diastolic blood pressures and required fewer medications for blood pressure control than those who completed the 30 weeks. For these reasons, patients in the former group may have been less highly motivated to complete the study. These observations suggest that modest dietary sodium ion restriction is feasible in treated hypertensive patients and that adherence to such a regimen may permit blood pressure control with fewer medications.

Adult↗