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Biomedical subjects

R Friedman

Publications and source records attributed to R Friedman.

At least 253 records · Page 14Linked to original sources
PubMedDate not supplied

Pharmacology, therapeutic efficacy, and adverse effects of bumetanide, a new "loop" diuretic.

Bumetanide is a recently developed natriuretic and diuretic agent, belonging to the "loop" class of diuretics. Since it is rapidly and almost completely absorbed after oral administration, oral and parenteral formulations have a similar pharmacokinetic profile. Peak plasma levels are achieved approximately 30 min after oral administration. The apparent half-life is 1.2-1.5 hr, and the volume of distribution is about 25 liters. Plasma clearance is 228-255 ml/min. Bumetanide is promptly and almost completely eliminated by metabolism of the butyl side chain and urinary excretion of the parent drug and its metabolites. The principle renal site of action is the ascending limb of the loop of Henle, with a minor effect on the proximal tubule. The drug causes decreases in both free water clearance (during water diuresis) and solute free water reabsorption (during hydropenia), increased fractional delivery of sodium chloride to the distal tubule and a natriuresis approaching 20% of the filtered load of sodium, calciuria, phosphaturia, and minimal bicarbonaturia. Extensive clinical studies have been conducted with both oral and parenteral bumetanide in patients with a variety of edematous conditions. The agent has been clearly demonstrated to be an effective diuretic in the treatment of edema due to cardiac disease (congestive heart failure) and edema, with or without ascites, due to hepatic disease. Bumetanide has also been shown effective in treating edema due to renal disease, even when modest to severe renal insufficiency is present, and it may be useful in the treatment of edema refractory to other loop diuretics. As would be predicted for any potent diuretic, bumetanide administration has been associated with hypokalemia, hypochloremia, metabolic aklalosis, hyperuricemia, and prerenal azotemia. Alterations in glucose metabolism are an inconsistent finding. Transient thrombocytopenia and granulocytopenia have been noted, but no consistent or important alterations in biochemical parameters have been observed. In some patients, especially those with renal failure receiving high doses, myalgias and muscle tenderness have been described. To date only a very limited potential for ototoxicity has been observed. Bumetanide has been administered without difficulty to patients having side effects from other loop diuretics.

Animals↗
PubMedDate not supplied

Magnetic resonance imaging of bioabsorbale polylactic acid interference screws during the first 2 years after anterior cruciate ligament reconstruction.

Bioabsorbable screws composed of poly(L-lactic acid) (PLA) were used for graft fixation and studied prospectively with serial magnetic resonance imaging (MRI) scans at 8, 16, and 24 months after autogenous patellar tendon anterior cruciate ligament (ACL) reconstruction in 10 patients. Conventional spin echo, proton density, and T2-weighted double echo sequences were obtained, as well as T2-weighted fat-saturated fast spin echo sequences. All but one of the screws (19 of 20) were evident in all serial scans. These showed minimal decrease in size over time. The one screw that had completely disappeared 8 months after reconstruction had cracked during insertion. None of the reconstructed ACL grafts showed clinical instability, persistent effusions, or detectable adverse reactions to the screws. Two patients developed abnormal signal in the tibial tunnel: one developed fluid anterior to the graft, and the other developed increased signal within the graft. The abnormal signal resolved with time in both patients. Other than the preceding changes, no abnormalities were detected on conventional sequences. Fat-saturated fast spin echo sequences showed a variable amount of increased signal around the tunnels, suggesting edema or fibrovascular marrow changes. The changes noted near the tunnels on the fat-suppressed scans most probably represent a general reaction to surgical insult rather than a reaction to the bioabsorbable screws, as similar changes were noted at the patellar harvest site.

Absorbable Implants↗
PubMedDate not supplied

Participation of the central cholinergic system in blood pressure regulation in the Dahl rat model of essential hypertension.

Participation of the cholinergic system in the regulation of blood pressure (BP) in the Dahl salt-sensitive (DS) and salt-resistant (DR) rat model of essential hypertension was investigated. It was found that systemic administration of 0.25 or 0.50 mg/kg physostigmine (PSTG) to unanesthetized, normotensive DS and DR rats caused a significant elevation in BP but did not affect heart rate. At both dose levels, the pressor response was markedly greater and significantly longer in DS rats than in DR rats. The response in both DS and DR rats was blocked by pretreatment with atropine sulfate but not with atropine methylnitrate. These results suggest that the pressor effects of PSTG are mediated by central cholinergic mechanisms, and enhanced central cholinergic activity may participate in the pathogenesis of hypertension in the DS rat.

Animals↗
PubMedDate not supplied

The effect of chronic conflict on the blood pressure of rats with a genetic susceptibility to experimental hypertension.

Rats with a genetic susceptibility to experimental hypertension were exposed daily for 13 weeks to a conflict situation that resulted in food deprivation and the application of electric shock. Other subjects were either food deprived, shocked, both food deprived and shocked but without conflict, or not experimentally manipulated (control). Despite weekly fluctuations, a pattern emerged wherein subjects exposed to conflict usually exhibited the highest systolic blood pressures followed in order by subjects exposed to food deprivation and shock without conflict, rats food deprived, rats exposed to shock, and control subjects. Following this 13 week period, some of the rats in each group were allowed a 13 week stress-free-recovery period while the rest of the subjects were treated as before. During the recovery period most subjects' blood pressure returned to control levels. However, there was some indication in a few rats that elevations could persist for extended periods after the aversive treatment had been terminated. There is probably a genetic component involved in the reaction to stress that promotes the development of hypertension, just as there is to other hypertensinogenic stimuli.

Animals↗
PubMedDate not supplied

Psychologic differences between high-, normal-, and low-renin hypertensives.

Sixty-one male subjects with mild untreated essential hypertension were classified by renin-sodium profiling as high renin (HR--13 Subjects), normal renin (NR--33 Subjects), or low renin (LR--15 Subjects). The HR subjects reported significantly more symptoms of sensitivity, depression, anxiety, hostility, paranoia, and psychotic thought than LR subjects on the Symptom Checklist (SCL-90). The NR subjects also reported more symptomatology than LR subjects. Similar differences between HR and LR subjects were found with the Cattell 16 Personality Factor Questionnaire (16PF).

Adult↗
PubMedDate not supplied

Psychological variables in hypertension: relationship to casual or ambulatory blood pressure in men.

OBJECTIVE: The evidence linking hypertension with personality or psychological characteristics, such as anger, anxiety, or depression, remains equivocal. This may be due in part to limitations of personality theory, confounding by awareness of hypertension, and/or inherent difficulties in measuring blood pressure. This study was designed to investigate the association between mild hypertension as defined by both ambulatory and casual (clinic) blood pressure measurements and various measures of personality and psychological characteristics. METHODS: We examined this association in a population-based sample of 283 men between the ages of 30 and 60 years from eight work sites in New York City, using an ambulatory blood pressure monitor and controlling for age, race/ethnicity, and body mass index. RESULTS: We found no consistent difference between participants with mild hypertension and those with normal blood pressure on any of the psychological variables assessed, including Type A behavior pattern, state and trait anger, anger expression, anxiety, symptoms of psychological distress, locus of control, or attributional style. Results were not due to the use of antihypertensive medication by some of the participants with hypertension nor to the dichotomization of blood pressure into those with and without mild hypertension. This contrasts with previous findings from this study showing a sizable association of ambulatory blood pressure and hypertension with job strain (a situational measure), age, and body mass index. CONCLUSIONS: These null results suggest that situational, biological, and perhaps behavioral factors are the primary determinants of mild hypertension and that the predictive significance of psychological or dispositional factors is low or negligible in those without overt cardiovascular disease.

Adult↗
PubMedDate not supplied

The noisy elderly patient: prevalence, assessment, and response to the antidepressant doxepin.

To measure the prevalence of noisy behavior as a nursing problem, a survey of head nurses was done in a chronic care hospital to identify patients whose vocalizing was frequently disturbing to other patients, staff, or visitors. We found 17 patients among the total of 154. Subsequently, the medical records of 13 surviving subjects were reviewed more exhaustively, and 11 were described as disruptive, usually when they were left alone. Of these "lonely" patients, eight had a previously documented diagnosis of depression. All were demented. Antipsychotic medication had previously been given to all 11 "lonely" patients, but had failed to control their disruptive behavior. Empirically, six patients were treated with doxepin, and in five, all with a history of previous depression, agitation and noisiness diminished. These observations suggest that the prevalence rate of disturbingly noisy behavior among long-term institutionalized elderly patients is about 11% and that the disturbingly noisy patient is often demonstrating depression in conjunction with dementia.

Aged↗
PubMedDate not supplied

Oral hygiene following traumatic brain injury: a programme to promote dental health.

Dental care and oral hygiene programmes for persons with traumatic brain injury (TBI) have been relatively ignored areas of clinical care and research. Data regarding the need for structured oral hygiene programmes with this population are sorely lacking. Further, evidence to support or contraindicate the efficacy of such interventions is negligible. The purpose of the present study was to address the need for ongoing dental follow-up and oral hygiene programmes in the post-acute phase of rehabilitation care. A group of 20 TBI patients (10 experimental, 10 control) who were at least 1 month post-injury and had Rancho Los Amigos Scale scores of 6 or greater, were randomly selected for participation in the study. Oral hygiene status was assessed by a dental hygienist using a plaque index score developed by Silness and Loe. The experimental group received individualized oral hygiene instruction along with dental supplies for their personal use, including a dental mirror and red disclosing tablets. The control group received no such instructions or supplies. At 5-6 weeks following initial evaluation, 18 patients (nine from each group) were reassessed via the plaque index score. Comparisons between the control and experimental groups revealed significant differences on follow-up plaque scores with a lower mean score for the experimental group only on baseline and follow-up data yielding a significant decrease in plaque scores over time. These results suggest that dental hygiene interventions for patients following TBI can effectively promote dental plaque control.

Adult↗
PubMedDate not supplied

The case of the religious network group.

GenCorp, a Connecticut-based paper-goods manufacturer, has long supported employee-organized network groups. Its social support group for African-Americans, in fact, has been a particular success, having provided black employees with opportunities to further enhance their careers and helped the company retain top talent, meet its EEO goals, and gain favorable publicity. So when Alice Lawrence, a top accountant at GenCorp, called general manager Bill Thompson about the Christian network group being organized in one of the company's southern plants, Bill hardly flinched. After all, the Christian group was being organized by Russell Kramer, one of the company's most effective plant managers. What could be the problem there? But a couple of years ago, Alice noted, Russell had sent around a companywide letter that talked about the sinful nature of homosexuality. And that letter has made her and other gay and lesbian employees terribly uneasy. To complicate matters, the issue of "Christian rights" in the workplace was being widely discussed on radio talk shows, and several books on the topic had recently been published. An employee had even called the new region's head of human resources to get clarification on the topic. Up until now, GenCorp hadn't placed a lot of restrictions on network groups. But the emergence of a religious group was raising new questions for GenCorp's managers. Should the company accept religious groups or try to stop them? What policy, if any, should GenCorp adopt toward these network groups? Five experts comment on this fictional case study.

Christianity↗
PubMedDate not supplied

Statistical packages for the Macintosh.

These programs represent the entry of the Mac into major statistical computing. We believe that for the physician researcher who is not a statistician, they make the Mac the platform for data analysis. We found that statistics, research design, and data analysis seemed different and much less intimidating to us and our trainees when approached through the Mac. We have reviewed the versions of these programs available at the time of this writing, in May 1992; potential buyers should contact the software publisher for information about more recent upgrades. At this point, our recommendations would be as follows: If you are wedded to SPSS or Minitab, try the Mac versions, and you will be impressed. Otherwise, the choice is between SYSTAT, which has been around long enough to demonstrate its richness and capacity to build on its strengths, and JMP, a brash newcomer, which demonstrates that you can teach an old dog (SAS) new tricks. StatView and SuperANOVA, while endowed with intuitive, easy-to-use interfaces, lack online help--a feature we consider important in a statistics package. We anticipate that the future will lead to simplification of the SYSTAT interface and the addition of more analytic capacities to JMP--and who knows what the next generation of competitors will bring?

Computer Systems↗
PubMedDate not supplied

Pseudoconduction of atrial flutter of a recipient atrium.

A nine-year-old girl had an episode of atrial flutter and a nonsustained wide QRS tachycardia during her initial hospitalization after orthotopic heart transplantation. Evaluation of her ECG and telemetric tracing revealed atrial flutter of the recipient atrium and sinus rhythm of the donor atrium. The wide QRS tachycardia was an accelerated ventricular rhythm that was also found on subsequent 24-hour ambulatory ECG monitoring. Timely recognition of recipient atrial arrhythmias prevents inappropriate clinical intervention.

Atrial Flutter↗