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Biomedical subjects

H Schwartz

Publications and source records attributed to H Schwartz.

At least 55 records · Page 3Linked to original sources
PubMed1987

Short-term toxicity studies of sanguinarine and of two alkaloid extracts of Sanguinaria canadensis L.

The short-term toxicity of sanguinarine, a benzophenanthridine alkaloid, and of two alkaloid extracts of Sanguinaria canadensis L. are presented. The acute oral LD50 in rats of sanguinarine was calculated to be 1658 mg/kg, and of the two alkaloid extracts, 1440 and 1250 mg/kg. The acute iv LD50 in rats of sanguinarine was found to be 29 mg/kg. No toxic effects were observed in rats fed up to 150 ppm sanguinarine in the diet for 14 d and in rats treated by gavage with up to 0.6 mg/kg body weight for 30 d. The acute dermal LD50 in rabbits was found to be greater than 200 mg/kg.

Administration, Cutaneous↗
PubMed1987

Metabolism of 1,2,3,4-, 1,2,3,5-, and 1,2,4,5-tetrachlorobenzene in the squirrel monkey.

The metabolism of three tetrachlorobenzene isomers (TeCB) was investigated in the squirrel monkey. The animals were administered orally 6 single doses of 14C-labeled 1,2,3,4-, 1,2,4,5-, or 1,2,3,5-tetrachlorobenzene over a 3-wk period at levels ranging from 50 to 100 mg/kg body weight (b.w.) and kept in individual metabolism cages to collect urine and feces for radioassay. Approximately 38% (1,2,3,4-TeCB), 36% (1,2,3,5-TeCB), and 18% (1,2,4,5-TeCB) of the doses were excreted respectively in the feces 48 h postadministration. In monkeys dosed with 1,2,3,4-TeCB, unchanged compound accounted for 50% of the fecal radioactivity; its fecal metabolites were identified as 1,2,4,5-tetrachlorophenol (TeCP, 22%), N-acetyl-S-(2,3,4,5-tetrachlorophenyl) cysteine (18%), 2,3,4,5-tetrachlorophenyl sulfinic acid (3%), 2,3,4-trichlorophenyl methyl sulfide (0.6%), and 2,3,4,5-tetrachlorophenyl methyl sulfide (0.2%). As was the case with 1,2,3,4-TeCB, unchanged compound accounted for more than 50% of the fecal radioactivity found in the monkeys dosed with 1,2,3,5-TeCB. The fecal metabolites of 1,2,3,5-TeCB consisted of 2,3,4,5-TeCP (2%), 2,3,4,6-TeCP (14%), 2,3,5,6-TeCP (9%), and 2,3,5,6-tetrachlorophenyl sulfinic acid (15%). No metabolites were detected in the feces of monkeys dosed with 1,2,4,5-TeCB. While the fecal route represented the major route of excretion for 1,2,3,4-TeCB, the other two isomers were eliminated exclusively in the feces. The above data in the squirrel monkey are different from those obtained with the rat and the rabbit, and demonstrate the different metabolic pathways for the isomers.

Animals↗
PubMed1987

T3 stimulation of 2-deoxy-D-glucose uptake in cultured chick embryo carcass derived cells, requires neosynthesis of proteins.

T3 stimulated, in a dose dependent manner, the uptake of 2-deoxy-D-glucose (2-DOG) into cultured chick embryo carcass derived cells. A significant increase in sugar uptake was seen already at a T3 concentration of 1 pmol/l. The stimulation of 2-DOG uptake increased with time during the 6 h of exposure to T3. The hormone also stimulated, within 45 min, the incorporation of [3H]leucine and [3H]uridine into the trichloroacetic acid precipitable material of these cells. Actinomycin-D (100 micrograms/l) and cycloheximide (1 mg/l) each were capable of blocking the stimulatory effect of 10(-8) mol/l T3 on sugar uptake and on uridine and leucine incorporation. Thus, T3 in these cultured chick embryo cells stimulated sugar transport through processes dependent on neosynthesis of proteins. In this respect the effect of T3 is different from that seen in cultured chick embryo cardiomyocytes.

Animals↗
PubMed1987

Anterior guidance and aesthetics in prosthodontics.

Aesthetic determinants in prosthodontics are related to imprecise and often vague objective and subjective factors. Anatomic and functional studies indicate parameters of form, position, and contour of anterior teeth and the incisal guide angle. The final aesthetic composition is best determined by a continuing, ongoing evaluation designed to help the patients actively develop a perception of their own self-image and aesthetic potential. Incisal guide factors are determined independently of condylar elements. The final occlusal scheme is developed and coordinated with both the condylar and incisal guide elements.

Biomechanical Phenomena↗
PubMed1986

The stimulation of sugar transport in heart cells grown in a serum-free medium by picomolar concentrations of thyroid hormones: the effects of insulin and hydrocortisone.

Chick embryo heart cells were propagated in a defined serum-free medium. They formed a confluent, synchronously contracting monolayer that is not different from myocytes grown in serum containing media. The uptake of 2-deoxy-D-[1-3H]glucose in these cells was stimulated by exposure to physiological concentrations of T3 (1 pM) and T4 (10 pM). Actinomycin-D and puromycin did not block the stimulation of 2-deoxy-D-[1-3H]glucose uptake when given with T3 throughout a 6-h incubation period. Cells grown in the absence of both insulin and hydrocortisone were unresponsive to T3. Insulin at 200 nM restored the sensitivity of the cells to 0.1 pM T3. Addition of 10 nM hydrocortisone to the growth medium enhanced the effects of T3 synergistically. The T3-stimulated sugar uptake was completely blocked by 5 X 10(-6) M cytochalasin B, suggesting that T3 acts, like insulin, by the translocation of glucose transporters to the plasma membrane.

Animals↗
PubMed1986

Congenital aneurysm of the left sinus of Valsalva. Report of a patient with 19-year survival without surgery.

An unruptured aneurysm of the left sinus of Valsalva was diagnosed by angiography in a 16-year-old male subject 19 years ago. A recent repeated angiographic study documented no change in the aneurysm over the 19-year interval, and the patient has remained asymptomatic. We are aware of no other long-term follow-up reports of patients with this lesion who have not had surgical correction. This case emphasizes the controversy regarding the need for prophylactic surgical correction of an unruptured aneurysm.

Adult↗