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Biomedical subjects

R Hart

Publications and source records attributed to R Hart.

At least 127 records · Page 7Linked to original sources
PubMed1983

Tool mark determination in cartilage of stabbing victim.

Striations produced on rib cartilages by a knife were conclusively matched with the individual characteristics of the cutting edge of the knife. This was accomplished using Dip-Pak (cellulose acetate butyrate), Coe-Flex (polysulfide dental impression), and comparison microscopy. An absolute identification was made in which all significant striae matched the individual characteristics of the blade's cutting edge.

Adult↗
PubMed1978

Thallium-201 myocardial perfusion scintigraphy to evaluate patients after coronary bypass surgery.

To determine the utility of thallium-201 stress scintigraphy in assessing the results of coronary bypass surgery, chest pain, stress electrocardiograms and scintigrams were evaluated in 27 patients postoperatively. These findings were compared with coronary angiographic data in which a significant postoperative lesion was defined as 75 percent or more stenosis in a graft, its distal vessel or in an ungrafted native vessel. As an indicator of postoperative coronary lesions, chest pain lacked sensitivity (60 percent) and was nonspecific (20 percent). The stress electrocardiogram had poor sensitivity (60 percent) and good specificity (86 percent) but was not helpful in six patients who had equivocal or suboptimal tests. The scintigram had good sensitivity (77 percent) and was highly specific for the diagnosis of coronary stenosis. It was significantly more specific than chest pain (P less than 0.01), gave excellent localizing information and added to the accuracy of both conclusive and inconclusive stress tests. In nine patients with preoperative stress scintigrams, comparison of pre- and postoperative studies reflected the éffects of bypass surgery on coronary perfusion. Scintigraphy is a useful technique for the noninvasive evaluation of the patient after coronary bypass surgery, and postoperative scintigraphy alone is of great value in documenting surgical results.

Adult↗
PubMed1978

Chemical carcinogen alteration of SV40 virus induced transformation of normal human cell populations in vitro.

The frequency of simian papovirus 40 (SV40) induced transformation of human cells was enhanced after pretreatment with either napthylamine-2,N-methyl-N'-nitrosoguanidine (MNNG), N-acetyl-2-fluorenylacetamide (N-Ac-AAF), benzo[a]pyrene (BP), aflatoxin B1, propane sultone (PS), beta-propiolactone, 4-nitroquinoline oxide (4-NQO), methylmethane sulfonate (MMS) or diethyl nitrosamine (DEN). Posttreatment with 4-NQO, MMS, MNNG or DEN inhibited transformation; while posttreatment with either aflatoxin B1, beta-propiolactone or napthylamine-2 did not alter transformation similar to the action of N-Ac-AAF and BP. All carcinogens that altered transformation after pretreatment damaged cellular DNA. Pretreatment or posttreatment with carcinogens 3-methylcholanthrene (3-MCA) or 7,12-dimethylbenzanthrene (7,12-DMBA), that did not damage cellular DNA also did not enhance transformation. Moreover, pre- or posttreatment with other weak or non-carcinogens that did not damage cellular DNA did not alter virus induced transformation. All foci formed in the co-carcinogen treated cultures whether the carcinogen inhibited or enhanced transformation were virus directed. While a similar pattern of response existed for carcinogens that either enhance or inhibit transformation, each of the carcinogens that enhanced or inhibited foci formation damaged cellular DNA. Moreover, those carcinogens that enhanced focus formation, compared to the carcinogens that inhibited focus formation, exhibited similar DNA damage profiles.

Carcinogens↗
PubMed1978

Pitfalls and prospects in clinical research on antianxiety drugs: benzodiazepines and placebo--a research review.

The research methodology of 78 double-blind studies comparing benzodiazepines and placebo in treating neurotic anxiety is critically reviewed. Many faults are noted in areas of subject selection, assessment of clinical response, study design and data analysis. Although 56.4% of the studies reviewed had results demonstrating a significant difference in clinical response between benzodiazepines and placebo, the frequent methodologic difficulties and inconsistent results from study to study lead the authors to question the efficacy of these drugs as a treatment for anxiety. A need for better designed studies is discussed and some research methodologies proposed.

Anti-Anxiety Agents↗
PubMed1977

Hemodynamic advantage of combined administration of hydralazine orally and nitrates nonparenterally in the vasodilator therapy of chronic heart failure.

Patients with severe left ventricular failure generally have both reduced cardiac output and increased pulmonary and systemic venous pressures. A study was therefore made of the use of combined vasodilator therapy with nonparenterally administered nitrates, which act primarily on venous capacitance vessels and thus reduce preload, and orally administered hydralazine, which acts on arteriolar resistance vessels and thus reduces afterload. Twelve patients with chronic refractory heart failure were given these drugs individually and in combination during continuous hemodynamic monitoring. Heart rate and arterial pressure did not change significantly. Nitrates significantly reduced filling pressures of both ventricles without affecting cardiac index. Hydralazine did not alter filling pressures but dramatically increased cardiac index. The hemodynamic effects of each drug were additive during combined therapy, resulting in a 36 percent (28 to 18 mm Hg) mean decrease in left ventricular filling pressure and a 58 percent (2.1 to 3.3 liters/min per m(2)) mean increase in cardiac index. The seven patients who have continued to receive combined therapy for 3 to 10 months have shown sustained clinical improvement.

Administration, Oral↗
PubMed1977

Autoimmune progesterone dermatitis.

Seven patients had autoimmune progesterone dermatitis. The morphological findings illustrate the polymorphous nature of the disease in which urticaria, erythema multiforme, and dyshidrosiform lesions were seen. Recurrence of the eruption five to ten days prior to the menses with spontaneous resolution following the menses was present in all cases. Intradermal skin testing to progesterone was done to confirm the diagnosis. Six of the seven patients has a history of use of artificial progestational hormones prior to the beginning of their eruption. It is postulated that the artificial progesterones may have been the trigger for the development of their autosensitivity. Treatment with conjugated estrogens resulted in remission of the disease in five of the seven cases reported.

Adult↗