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Biomedical subjects

H S Sacks

Publications and source records attributed to H S Sacks.

At least 73 records · Page 4Linked to original sources
PubMed1986

Pharmacokinetics of mezlocillin in patients with hepatobiliary dysfunction.

The pharmacokinetics of mezlocillin were investigated in 26 patients with alcoholic liver disease. Serum concentrations of mezlocillin were measured following intravenous administration of 3 g doses over 30 min. The mean peak serum concentration (+/- standard deviation) of mezlocillin at the end of infusion was 138.8 +/- 55.7 mg/l and the mean terminal half-life (T 1/2 beta) was 2.10 +/- 0.9 h. The 24 h urinary recovery of mezlocillin was 35.4 +/- 12.4% of the administered dose. Serum clearance was found to be inversely correlated with alkaline phosphatase and with total bilirubin. The T 1/2 beta was related to the following clinical measurements: age, SGOT and prothrombin time. This relationship suggests it may be prudent to adjust the dosage and the dosage interval of mezlocillin in patients with hepatobiliary dysfunction.

Adult↗
PubMed1986

Transcutaneous oxygen monitoring during fiberoptic bronchoscopy.

A transcutaneous oxygen sensor was used to detect the development of hypoxemia in patients undergoing fiberoptic bronchoscopy. Measurements of transcutaneous PO2 (tcPO2) correlated well with arterial PO2 (PaO2), and correctly detected all instances when PaO2 was less than 65 mm Hg. The sensor was noninvasive and caused no adverse effects.

Adult↗
PubMed1985

Lumbar puncture in asymptomatic late syphilis. An analysis of the benefits and risks.

We evaluated the treatment of asymptomatic patients with untreated syphilis of more than one year's duration (asymptomatic late syphilis) using a decision-analysis model. Two strategies were compared: treatment with 7.2 million units of penicillin G benzathine, or performing a lumbar puncture to test for asymptomatic neurosyphilis followed by penicillin and management based on cerebrospinal fluid analysis. Estimates of probabilities of disease prevalence, test sensitivity, and cure and complication rates were derived from published studies. Both strategies resulted in a cure rate of at least 99.7% using the best estimates. Although the strategy using lumbar puncture results in a 0.2% higher cure rate, its rate of complications (0.3%) exceeds its marginal benefit. We conclude that a lumbar puncture offers little additional benefit and may increase morbidity in patients with asymptomatic late syphilis.

Headache↗
PubMed1984

Should the risk of acquired immunodeficiency syndrome deter hepatitis B vaccination? A decision analysis.

The current epidemic of acquired immunodeficiency syndrome (AIDS) and fear that its causative agent contaminates the currently available hepatitis B vaccine may have deterred vaccine use. We formulated a decision-analytic model that compares the risk of death from hepatitis B and AIDS in those vaccinated with the risk of death from hepatitis B alone in those who wait two years for a synthetic vaccine. For individuals with 5% annual risk of hepatitis B, the best current estimate is that vaccination now would save 25 lives per 100,000. The best current estimate of the rate of vaccine-induced AIDS is zero, and one can be 95% confident that the rate is less than eight per 100,000. The rate would have to be considerably higher before postponement of vaccination would be rational for those for whom vaccination has been recommended.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Longitudinal study of persistent generalised lymphadenopathy in homosexual men: relation to acquired immunodeficiency syndrome.

42 homosexual or bisexual men with persistent generalised lymphadenopathy not attributable to an identifiable cause have been followed longitudinally since February, 1981. Lymphadenopathy was accompanied by fatigue, low-grade fever and/or night sweats (57%), splenomegaly (29%), leucopenia (40%), hypergamma - globulinaemia (76%), and diminished proportion and absolute numbers of helper T cells (95%). Of the 26 patients who had lymph node biopsy, all showed benign reactive hyperplasia. After 15-30 (median 22) months, 8 patients have met criteria for the diagnosis of acquired immunodeficiency syndrome (AIDS). This outcome was associated with previous heavy nitrite inhalant use, with the presence of night sweats, with leucopenia, and with the triad of constitutional symptoms, splenomegaly, and leucopenia. In addition, a lower mean absolute helper T cell count and an increased frequency of anergy to mumps intradermal antigen and of herpes simplex virus isolation distinguished these patients from those remaining in the cohort, who seem to be stable and in some cases to have improved.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Malignancy in primary biliary cirrhosis. High incidence of breast cancer in affected women.

Primary biliary cirrhosis is characterized by abnormalities in both cellular and humoral immunity. It is associated with presumably autoimmune diseases such as Sjögren's syndrome, rheumatoid arthritis, and scleroderma. Sjögren's syndrome and scleroderma have been noted to have an increased frequency of malignancy. Of 208 patients with primary biliary cirrhosis, followed for one month to 15.9 years, extrahepatic malignancies developed in 11, six of whom were women with breast cancer, and one with hepatocellular carcinoma. The incidence of breast cancer was 4.4 times (p less than 0.01) the incidence expected from the rate prevailing in the same age range in a comparable normal population. The incidence of cancer in sites other than the breast and of primary hepatocellular tumor was not significantly increased.

Adenocarcinoma↗
PubMed1984

Peer review using a paired-comparison technique.

A paired-comparison technique is used to enable surgical residents and attending surgeons to make peer judgments of each other. Comparative peer judgments were made in three areas: the ability of the surgeon to make a diagnosis and to decide on a plan of active medical care, the operating ability of the surgeon, and the postoperative care of the patient. This method of peer judgment ensures the confidentiality of those making the judgments, and the analysis results in a final ranking of the surgeons and surgical residents with indicated significant differences (P less than 0.05) among them. The technique also includes an assessment of how consistent each judge is in making comparisons of fellow surgeons.

Clinical Competence↗
PubMed1984

Somatostatin metabolism: differences in clearance of N-terminal and central portions of molecule during perfusion of rat liver.

Clearance of cyclic somatostatin (SRIF) from a plasma-free recirculating medium containing human erythrocytes and a bovine albumin fraction was measured with site-specific N-terminal (sheep B) and central core-directed (R101) radioimmunoassays during perfusion of the isolated rat liver (3-4 g). With the N-terminal radioimmunoassay (RIA), the t 1/2, hepatic clearance, and extraction of somatostatinlike immunoreactivity (SLI) were 20.9 +/- 2.0 (SE) min, 2.82 +/- 0.27 ml/min, and 35.2 +/- 3.4%. Corresponding values for the centrally directed assay were 51.0 +/- 6.3 min, 1.16 +/- 0.14 ml/min, and 14.4 +/- 1.8%. Clearances of immunoprecipitable 125I-Tyr-SRIF and [125I-Tyr11]SRIF were 6.56 and 1.06 ml/min, respectively, and were not saturable by 1 microM Tyr-SRIF and SRIF, respectively. SRIF (1.26 +/- 0.09 nM) and SRIF-28 (1.34 +/- 0.14 nM) clearances determined by R101 RIA were similar. After SRIF-28 perfusion, high-performance liquid chromatographic analysis of SLI showed 86% to be retained with the SRIF-28 peak and 14% with the SRIF peak, suggesting no major conversion of SRIF-28 to SRIF. Des-(Ala1,Gly2)-N3-Ac-SRIF and dihydrosomatostatin were cleared more rapidly than SRIF. Clearance of SLI by the perfusate without the liver was 12-43% of liver clearance, depending on the peptide examined. These results support the hypothesis that aminopeptidase and endopeptidase activities are involved in SRIF clearance by the intact liver. The activities appear to function independently. The intrachain disulfide bond of SRIF may confer relative stability during its hepatic metabolism.

Animals↗
PubMed1983

Bias in treatment assignment in controlled clinical trials.

Controlled clinical trials of the treatment of acute myocardial infarction offer a unique opportunity for the study of the potential influence on outcome of bias in treatment assignment. A group of 145 papers was divided into those in which the randomization process was blinded (57 papers), those in which it may have been unblinded (45 papers), and those in which the controls were selected by a nonrandom process (43 papers). At least one prognostic variable was maldistributed (P less than 0.05) in 14.0 per cent of the blinded-randomization studies, in 26.7 per cent of the unblinded-randomization studies, and in 58.1 per cent of the nonrandomized studies. Differences in case-fatality rates between treatment and control groups (P less than 0.05) were found in 8.8 per cent of the blinded-randomization studies, 24.4 per cent of the unblinded-randomization studies, and 58.1 per cent of the nonrandomized studies. These data emphasize the importance of keeping those who recruit patients for clinical trials from suspecting which treatment will be assigned to the patient under consideration.

Clinical Trials as Topic↗
PubMed1983

Association of adrenocorticosteroid therapy and peptic-ulcer disease.

We reexamined the association between corticosteroid therapy and subsequent peptic ulceration or gastrointestinal hemorrhage by pooling data from 71 controlled clinical trials in which patients were randomized to systemic corticosteroids (or ACTH) or to nonsteroid therapy. Of 3064 steroid-treated patients evaluated for peptic ulcer, 55 (1.8 per cent) had ulcers, as compared with 23 of 2897 controls (0.8 per cent) (relative risk, 2.3; 95 per cent confidence interval, 1.4 to 3.7). Of 3135 steroid-treated patients evaluated for gastrointestinal hemorrhage, 78 (2.5 per cent) had bleeding, as compared with 48 of 2976 controls (1.6 per cent) (relative risk, 1.5; 95 per cent confidence interval, 1.1 to 2.2). The incidence of ulcers varied directly with the dosage of steroids. When separate analyses were performed for studies that were double-blind, used only oral steroids, used only parenteral steroids, or excluded patients with a history of ulcer, the trend remained consistent but did not always reach statistical significance. This study strongly suggests that corticosteroids do increase the risk of peptic ulcers and gastrointestinal hemorrhage.

Adrenal Cortex Hormones↗
PubMed1983

Physician attitudes toward applications of computer data base systems.

To determine the attitudes of internists and surgeons to problems in clinical information management and to the use of a computer data base, a survey of 529 internists and 487 otolaryngologists was conducted. The survey group consisted of a national distribution of academic physicians, private practitioners, and residents. Results of 296 completed questionnaires were analyzed for this report. More than one third of all responders were not satisfied with their ability to keep up with new developments; less than 10% were very satisfied. Ninety percent thought that a computer data base would improve their access to information in the literature, and 85% thought it would improve their practice of medicine. Among internists, randomized control trials (RCTs) were viewed as clearly the most useful source of data. Otolaryngologists indicated that RCTs and patient registries were both very helpful. Most physicians indicated significantly greater preference for literature summary and patient registry features over probability estimation capabilities of a computer data base. Sources of data to be incorporated into a successful data base would be different for systems designed for internists and otolaryngologists.

Attitude of Health Personnel↗
PubMed1983

Deficiencies of clinical trials of alcohol withdrawal.

Eighty-one therapeutic trials of alcohol withdrawal were found that have been published in English since 1954; controls were randomized in 29 (RCTs). Two thousand three hundred thirteen patients were randomized. Variable pretreatment description prevented estimates of delirium tremens and convulsion prevalence, but only four deaths were reported. Endpoints were thus entirely subjective in these moderately ill patients. Protocol quality of the RCTs was graded by a previously developed system for evaluating adequacy of descriptions, blinding, and essential measurements. Mean score obtained was .49 +/- .03 (1 SE). (A perfect paper would score 1.00.) Data presentations and statistical analyses scored .18 +/- .03. There was little evidence of improvement of scores over time. Papers lacked confidence intervals, proper handling of dropouts, and adequate details of side effects. In five RCTs, six comparisons showed that benzodiazepines are clearly superior to placebo (p less than .001), but conclusions about comparisons with other drugs were not possible. In none of eight "negative" comparisons was the probability of a type II error (beta) considered. Discovery of more effective symptomatic agents or methods of reducing the death rate will require more rigid protocols and analyses as well as larger studies to allow the use of more critical endpoints such as occurrence of delirium tremens, convulsions, or death.

Alcohol Withdrawal Delirium↗
PubMed1983

Sensitivity and specificity of clinical trials. Randomized v historical controls.

The relative accuracy of randomized control trials (RCTs) and historical control trials (HCTs) in determining effective therapies has not been compared since there is no external verification of efficacy. We reviewed six therapies studied by both methods. Most HCTs concluded therapy was better than control, but few RCTs agreed. We calculated sensitivity and specificity for each type of trial by combining published results with all possible combinations of effectiveness. The sensitivity of HCTs was 0.80 to 1.00 (mean, 0.90) and specificity was 0.0 to 0.27 (mean, 0.11). The sensitivity of RCTs was 0.0 to 0.27 (mean, 0.12) and specificity was 0.67 to 1.00 (mean, 0.88). Defects of RCTs are more easily corrected than those of HCTs. Readers should consider trial design and the probability of errors when deciding how much credence to give to a clinical trial.

Clinical Trials as Topic↗
PubMed1981

A survey of clinical trials of antibiotic prophylaxis in colon surgery: evidence against further use of no-treatment controls.

To evaluate the use of antibiotics given prophylactically of colon surgery, we examined 26 trials published from 1965 to 1980 in which patients given various antibiotic regiments were compared with controls given no antibiotic treatment. In 22 (85 per cent of these trials) antibiotics reduced postoperative wound infection (p less than 0.05 in 14). Combining the results of the trials published from 1965 to 1975 reveals a 95 per cent confidence interval from the true difference in infection rates of 14 +/- 6 per cent (36 per cent for control group vs. 22 per cent for treatment group) and the true difference in death rates of 6.7 +/- 4.4 per cent (11.2 per cent for control group vs 4.5 per cent for treatment group). Yet trials employing control groups given no treatment continue to be reported. Since the use of such controls is justified only when no effective alternative therapy exists, we believe that any further trials of antibiotic prophylaxis in colon surgery should employ a previously proved standard. However, steadily increasing efficacy of treatment means that comparisons of new therapies with standard therapies will become prohibitively expensive because of the large number of patients required.

Anti-Bacterial Agents↗
PubMed1981

Adult respiratory distress syndrome in Rocky Mountain spotted fever.

A culture-proved case of Rocky Mountain spotted fever is described in which the typical findings of the adult respiratory distress syndrome developed. Rocky Mountain spotted fever should be added to the list of conditions associated with the adult respiratory distress syndrome. This case also illustrates the difficulties in distinguishing Rocky Mountain spotted fever from atypical measles.

Adolescent↗