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Biomedical subjects

S I Gutman

Publications and source records attributed to S I Gutman.

15 recordsLinked to original sources
PubMed1997

Regulatory issues unique to clinical trials on periodontal diagnostic methods and devices.

A wide variety of in vitro diagnostic products have been proposed for use in patients with periodontal disease. The Food and Drug Administration (FDA) review focuses on three important issues. First, the product must exhibit acceptable analytical performance (accuracy, precision, analytical sensitivity, and analytical specificity). Second, the effectiveness of the device must be clearly defined. The studies required to establish this will depend largely on the proposed intended use of the product. At a minimum, clinical or diagnostic sensitivity and specificity should be established. Finally, the product must meet the labeling requirements for in vitro devices. These requirements outlined in CFR 809.10(b) are comprehensive and cover 15 key elements including information about the principles of the analytical method; handling of instruments, reagents, and patient samples; test limitations; and test performance. Applicants developing products for any in vitro diagnostic device are encouraged to review the labeling regulations along with other divisional and office guidance material to help in defining the submission requirements. The FDA is willing to meet and work with companies prior to and during preclinical and clinical trials to assist in the development of appropriate study protocols.

Clinical Trials as Topic↗
PubMed1992

Renal responses during a dry saturation dive to 450 msw.

Four subjects were compressed to a simulated depth of 450 msw (46 bar) for 37 days in the main research chamber of the German underwater simulator diving facility at the GKSS Research Center, Geesthacht. The ambient gas was trimix. Urine was collected at 0700, 1300, and 1900 h each day for analysis of Na+, K+, volume, osmolality, and creatinine. Urine, antidiuretic hormone (ADH), and aldosterone were analyzed separately. Daily fluid, Na+, and K+ intake were analyzed throughout the dive. The aim of the investigation was to confirm the existence of a diuresis and natriuresis which had been observed in earlier saturation dives to 31 atm abs using He-O2. A significant diuresis was observed during compression despite a decrease in fluid intake. After compression the diuresis decreased somewhat but remained significantly above precompression control levels during the entire hyperbaric exposure. No significant change in fluid intake was observed. Daily Na+ and K+ excretion increased significantly during compression, which was accompanied by a significant increase in nocturnal excretion of Na+ and K+. Daily intake of Na+ and K+ decreased throughout the dive. Daily urine ADH decreased immediately upon compression and was associated with a parallel decrease in urine osmolality. In contrast, urinary aldosterone excretion exhibited no change during the dive despite the increase in Na+ and K+ excretion and decrease in Na+ intake.

Aldosterone↗
PubMed1991

Comparison of 2,3,7,8-tetrachlorodibenzo-p-dioxin-mediated hepatotoxicity in C57BL/6J and DBA/2J mice.

The toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was examined by clinical chemistry and liver histopathology in Ah-responsive C57BL/6J (C57) and Ah-nonresponsive DBA/2J (DBA) mice. Hepatotoxicity was assessed at 1, 3, and 7 d following a single ip injection of TCDD at doses that maximally induce hepatic aryl hydrocarbon hydroxylase (AHH) activity (3 micrograms/kg for C57 and 30 micrograms/kg for DBA mice) and at doses approaching the LD50 (150 micrograms/kg for C57 and 600 micrograms/kg for DBA mice). Histological examination of liver sections was found to be a more sensitive detection method for TCDD-induced hepatic changes than clinical chemistry analyses. Dramatic differences in the development and type of liver injury were observed between TCDD-treated C57 and DBA mice. C57 mice given 3 micrograms TCDD/kg developed mild to moderate hepatic lipid accumulation in the absence of both inflammation and necrosis. Severe fatty change and mild inflammation and necrosis occurred in C57 mice that received 150 micrograms TCDD/kg. In contrast, DBA mice exposed to 30 micrograms TCDD/kg developed hepatocellular necrosis and inflammation without any fatty change. Only slight hepatic lipid accumulation occurred with some necrosis and inflammation in DBA mice given 600 micrograms TCDD/kg. The Ah locus may play a role in determining the sensitivity of C57 mice to the steatotic effects of TCDD.

Animals↗
PubMed1990

A comparison between erythrocyte sedimentation rate (ESR) and selected acute-phase proteins in the elderly.

The erythrocyte sedimentation rate (ESR) and selected acute-phase proteins (APPs) were studied in 101 elderly people (mean age, 72 years) to determine their utility as diagnostic aids in subjects with underlying infections or inflammation. ESR and values for serum immunoglobulin A (IgA), the fourth component of complement (C4), haptoglobin, and alpha-1-antitrypsin (AAT) all correlated with infection or inflammation. C4 was the only test predictive of mortality at six months. Neither ESR nor any of the APPs demonstrated concomitantly high sensitivity, specificity, and positive predictive values. Receiver-operating characteristic curve analysis revealed low true positive to false positive ratios for all of the tests studied. In the elderly, measurement of APPs as a guide to underlying infection or inflammation has limited utility and offers no advantage over the traditional low-cost ESR.

Acute-Phase Proteins↗
PubMed1989

Comparative antimycobacterial activities of difloxacin, temafloxacin, enoxacin, pefloxacin, reference fluoroquinolones, and a new macrolide, clarithromycin.

The activities of fluoroquinolones and a new macrolide against 30 clinical isolates of Mycobacterium tuberculosis were determined in vitro by agar diffusion. In order of relative potencies against M. tuberculosis, temafloxacin (MIC for 90% of isolates [MIC90], 2.3 micrograms/ml) was at least as active as the reference quinolones ofloxacin (MIC90, 2.4 micrograms/ml) and ciprofloxacin (MIC90, 4.3 micrograms/ml). Less active were difloxacin (MIC90, 4.7 micrograms/ml), pefloxacin (MIC90, 6.7 micrograms/ml), and enoxacin (MIC90, 8.3 micrograms/ml). The macrolide clarithromycin was more potent than erythromycin but less potent than the fluoroquinolones. Our results suggest that the newer fluoroquinolones and clarithromycin should be included with ciprofloxacin and ofloxacin in pharmacokinetic studies that may lead to trials in human subjects with mycobacterial infections.

Anti-Bacterial Agents↗
PubMed1989

Erythrocyte sedimentation rate and C-reactive protein compared in the elderly.

The erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) concentrations were studied in 101 elderly individuals (mean age 72 y) to determine their utility as diagnostic aids in subjects with underlying infection/inflammation. Whereas ESR and CRP were both significantly increased in patients with infection or inflammation, or both, analysis of variance indicated that those subjects still alive six months later had significantly lower ESR values. Analysis of sensitivity, specificity, and positive predictive values indicated that neither test satisfactorily discriminated between patients with and those without ongoing active or chronic disease. Receiver-operating characteristic curve analysis confirmed the low true-positive/false-positive ratios of both ESR and CRP. In the elderly, neither CRP nor ESR has distinct advantages over the other, and both tests evidently have limited utility.

Aged↗
PubMed1988

The use of laboratory intervention to stem the flow of fresh-frozen plasma.

Four methods of laboratory intervention were tested by the hospital blood bank in an effort to modify the use of fresh-frozen plasma (FFP). Over a one-year period, a utilization audit was serially initiated with feedback to physicians, a recurrent educational program was introduced for housestaff delineating guidelines for FFP use, a form was introduced requiring justification for FFP orders, and a policy was established requiring pathologist approval of FFP in patients with normal or no coagulation studies. Overall, in comparing the period following all forms of intervention (February 1986-October 1986) to the baseline period prior to any form of intervention (July 1984-March 1985), FFP use dropped 52% in the face of a 17% increase in red blood cell use. It was concluded that blood bankers can dramatically alter the use of this product using established methods for modifying physician ordering behavior.

Blood Banks↗
PubMed1988

Effect of nitroblue tetrazolium concentration on the fructosamine assay for quantifying glycated protein.

Experiments with nitroblue tetrazolium (NBT) at 0.25, 0.50, and 0.75 mmol/L confirmed that reactivity of 1-deoxy-1-morpholino-D-fructose, the standard, was more sensitive to reagent concentration than was protein ketoamine and demonstrated why an increase in NBT or a decrease in sample volume yields lower values for serum fructosamine. Analyses of clinical samples from diabetic and nondiabetic patients and from healthy subjects indicated that, with NBT at 0.25 mmol/L, discrimination between diabetics and other subjects was improved by changing the sample:reagent volume ratio from the usual 1:10 to 1:25 (9- to 12-min reading time). Discrimination improved further with NBT at 0.75 mmol/L and a 1:25 ratio but a later reading time (18-21 min); these conditions may minimize the effects of some but not all interferents.

Adult↗
PubMed1987

The clinical significance of dipstick-negative, culture-positive urines in a veterans population.

The consequences of omitting cultures in dipstick-negative urines submitted to the authors' microbiology laboratory were evaluated retrospectively in 1,079 clean-catch midstream samples. Using positive dipstick readings for leukocyte esterase, nitrite, and/or protein as evidence of a positive screen, the sensitivity, specificity, positive predictive value, and negative predictive value for specimens containing more than or 10(3) CFUs/mL (10(6)/L) were 80%, 71%, 48%, and 91%, respectively. Clinical data were reviewed in 38 patients with one or more dipstick-negative, culture-positive urines. Most of these patients lacked clinical or other laboratory evidence suggesting urinary tract infection. Problems with specimen collection were suspected in 19 neurologically compromised patients. Only two patients with dipstick-negative urines received treatment based on the culture reports. Symptoms persisted in both. The authors conclude that in their predominantly male veteran population, clinically significant bacteriuria is an unlikely finding in a dipstick-negative urine.

Aged↗
PubMed1980

Two new artifacts in automated coagulation testing.

Two artifacts were noted during the routine use of the Sherwood Lancer Coagulyzer. The first was that prothrombin times for 44 patients were greater than 90 sec on the Sherwood instrument, but were significantly shorter using reference methods. All 44 patients had subnormal fibrinogen values. Continuous optical density tracings during clotting performed for 11 patients demonstrated low slopes and amplitudes. For the three patients tested, the addition of fibrinogen corrected prothrombin times to values similar to those obtained on the Bio-Data instrument. Twenty-four of the patients subsequently died, 20 within three weeks of the observation of the artifact. The second artifact was that activated partial thromboplastin times for 12 patients were 9 sec on the Sherwood instrument, but were either normal or prolonged when using reference methods. Continuous tracings performed for nine patients demonstrated early optical density increases before clotting, which were responsible for the spurious values. Eleven of the 12 patients were hypoalbuminemic, and nine of the ten tested had elevated IgM levels. For seven patients, the artifact disappeared with in-vitro correction of hypoalbuminemia. Far from being weaknesses of the Coagulyzer, these artifacts may lead to the discovery of unsuspected, clinically significant laboratory information.

Blood Coagulation Tests↗
PubMed1976

Methyldopa Hepatitis. A report of six cases and review of the literature.

Six cases of methyldopa hepatitis, including two in which the patients died are reported; and 77 cases from the literature are reviewed. Patients in whom severe hepatotoxic reactions to methyldopa develop usually complain of prodromal symptoms typical of hepatitis, often with fever, one to four weeks after therapy is initiated. Jaundice, when it occurs, is usually manifest within three months. Asymptomatic, transient elevations of serum transaminase levels may occur in patients receiving methyldopa. However, since the clinical and histologic features of hepatic injury from methyldopa are indistinguishable from viral hepatitis, it is suggested that the incidence of this iatrogenic disease is higher than generally appreciated. Serum transaminase levels should be determined at the initiation of therapy with methyldopa and four weeks later. Moreover, any patient who has unexplained fever or the prodromal symptoms of hepatitis should undergo liver chemistry studies immediately.

Adrenal Cortex Hormones↗