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Biomedical subjects

A C Smith

Publications and source records attributed to A C Smith.

At least 163 records · Page 9Linked to original sources
PubMed1988

Comparison of covalent binding from halothane metabolism in hepatic microsomes from phenobarbital-induced and hyperthyroid rats.

1. Hepatic microsomal suspensions from rats pretreated with saline, phenobarbital or triiodothyronine were incubated with 14C-halothane under aerobic and anerobic conditions. 2. Metabolism of halothane by microsomes from phenobarbital-induced rats under anaerobic conditions resulted in covalent binding of 14C to microsomal lipids, and to a lesser extent, microsomal proteins, as seen in previous studies. Covalent binding was decreased with incubation under aerobic conditions. 3. Metabolism of halothane by microsomal suspensions from hyperthyroid rats produced much less covalent binding to microsomal lipids and proteins, with binding similar to, or less than, that observed with microsomes from saline-treated rats. The covalent binding of halothane to protein of microsomes from hyperthyroid rats was dependent upon metabolism, and was inhibited by SKF 525A, reduced glutathione, or cytosol. 4. The in vitro observations with respect to covalent binding are inconsistent with previous reports on halothane hepatotoxicity in hyperthyroid rats in vivo. This inconsistency and the relatively small extent of covalent binding with microsomes from hyperthyroid rats observed, suggests that covalent binding is not an important mechanism of halothane hepatotoxicity in the hyperthyroid rat model.

Animals↗
PubMed1988

Swine as models in experimental surgery.

The use of swine in surgical research has undergone a dramatic increase in recent years, due to decreasing availability of dogs as surgical models and a renewed interest in the porcine model based on anatomic and physiologic characteristics. This article reviews the issues involved in selection of swine as experimental surgical subjects including procurement considerations, anesthetic selection, housing methods, and anatomic and physiologic characteristics.

Anesthesia↗
PubMed1987

In vivo binding of 3H-N-methylspiperone to dopamine and serotonin receptors.

3H-N-methylspiperone (3H-NMSP) was used to label dopamine-2 and serotonin-2 in vivo in the mouse. The striatum/cerebellum binding ratio reached a maximum of 80 eight hours after intravenous administration of 3H-NMSP. The frontal cortex/cerebellum ratio was 5 one hour after injection. The binding of 3H-NMSP was saturable in the frontal cortex and cerebellum between doses of 10 and 1,000 micrograms/kg. Between 0.01 and 10 micrograms/kg the ratio total/nonspecific binding increased from 14 to 21. Inhibition of 3H-NMSP binding in the frontal cortex and striatum by ketanserin, a selective serotonin-2 antagonist, demonstrated that 20% of the total binding in the striatum was to serotonin-2 receptors and 91% of the total binding in the frontal cortex was to serotonin-2 receptors. Compared to 3H-spiperone, 3H-NMSP results in a much higher specific/nonspecific binding ratio in the striatum and frontal cortex and displays more than a two-fold higher brain uptake.

Animals↗
PubMed1987

Structural organization of the human glucocorticoid receptor determined by one- and two-dimensional gel electrophoresis of proteolytic receptor fragments.

The structural organization of the steroid-binding protein of the IM-9 cell glucocorticoid receptor was investigated by using one- and two-dimensional gel electrophoresis of proteolytic receptor fragments. One-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of receptor fragments isolated after trypsin digestion of immunopurified [3H]dexamethasone 21-mesylate ([3H]DM-) labeled receptor revealed the presence of a stable 26.5-kilodalton (kDa) steroid-containing, non-DNA-binding fragment, derived from a larger, less stable, 29-kDa fragment. The 26.5-kDa tryptic fragment appeared to be completely contained within a 41-kDa, steroid-containing, DNA-binding species isolated after chymotrypsin digestion of the intact protein. Two-dimensional electrophoretic analysis of the [3H]DM-labeled tryptic fragments resolved two (pI congruent to 5.7 and 7.0) 26.5-kDa and two (pI congruent equal to 5.7 and 6.8) 29-kDa components. This was the same number of isoforms seen in the intact protein, indicating that the charge heterogeneity of the steroid-binding protein is the result of modification within the steroid-containing, non-DNA-binding, 26.5-kDa tryptic fragment. Two-dimensional analysis of the 41-kDa [3H]DM-labeled chymotryptic species revealed a pattern of isoforms more complex than that seen either in the intact protein or in the steroid-containing tryptic fragments. These results suggest that the 41-kDa [3H]DM-labeled species resolved by one-dimensional SDS-PAGE after chymotrypsin digestion may be composed of several distinct proteolytic fragments.

Affinity Labels↗
PubMed1987

Detection of protein variation in human serum by externally released precipitins from the blue crab, Callinectes sapidus.

1. A number of invertebrate species releases precipitins into the environment. This process is apparently part of an externally directed immunologic system. 2. A saline solution of precipitins released from the blue crab, Callinectes sapidus, provided a reagent that produced two different precipitation reactions with proteins from the sera of human individuals. 3. One of the reaction variants was also detected with mammalian antiserum, the other was not. The former variant was associated with a medical condition: hypergammaglobulinemia. 4. Saline reagents from different invertebrate species may prove useful in clinical diagnosis and for revealing new human protein polymorphisms.

Animals↗
PubMed1987

A precipitin for human serum proteins as released into the environment by stressed bait shrimp, Penaeus duorarum.

1. A precipitin for human serum proteins is released into the environment by stressed bait shrimp, Penaeus duorarum. 2. Two-dimensional crossed immunoelectrophoresis revealed that the precipitin reacts (a) primarily with proteins belonging to the major group, alpha-1 globulin; and (b) with more proteins than a standard mammalian antiserum. 3. This study extends the variety of species known to liberate precipitins and suggests this response may be widespread among invertebrates. 4. The precipitins are easily collected in saline solution and, by virtue of their unique specificities, are potentially useful in diagnostic testing.

Animals↗
PubMed1987

Chondroid osteosarcoma of the maxilla.

A case of chondroid osteosarcoma of the maxilla is reported. This is itself a rare lesion but in this instance diagnosis was made more difficult for 2 reasons. On presentation, there was little radiological evidence of bone destruction and also, during follow-up and before biopsy-proven diagnosis, the lesion showed considerable evidence of repair on 2 occasions.

Adult↗
PubMed1987

Substituted 1,3,4-thiadiazoles with anticonvulsant activity. 3. Guanidines.

The synthesis and anticonvulsant activity of a number of 2-aryl-5-guanidino-1,3,4 thiadiazoles are described. The unsubstituted guanidine 2a was found to possess potent anticonvulsant properties; considerable reduction or loss of activity however was observed with the majority of the substituted guanidines. Incorporation of the guanidine group into an imidazoline ring also resulted in a loss of activity. Secondary pharmacological evaluation confirmed the anticonvulsant properties of 2a but also revealed that the compound exhibited a considerable degree of sedative activity.

Animals↗
PubMed1987

A combined regimen of controlled motion following flexor tendon repair in "no man's land".

A program of controlled motion following repair of flexor tendons in the hand is presented. This regimen incorporates the features of active extension against rubber band passive flexion, as well as those of controlled passive extension and passive flexion. In this prospective study, 44 digits with complete lacerations of the flexor digitorum profundus and flexor digitorum superficialis in zone 2 were treated. Using the Strickland formula of total active motion of the interphalangeal joints, 36 fingers (82 percent) were rated "excellent"; 7 fingers (16 percent) were rated "good"; 1 finger (2 percent) was rated "fair"; none was rated "poor". There was no statistical difference between the results of delayed primary repair and immediate primary repair.

Adolescent↗
PubMed1987

Biosynthesis and secretion of human colonic mucin glycoproteins.

Synthesis and secretion of colonic mucin glycoprotein species were assessed during in vitro culture of colonic mucosal explants. DEAE-cellulose chromatography of endogenously labeled mucin glycoproteins from explant tissue demonstrated the presence of six mucin species (I-VI) similar to those identified earlier in surgical specimens of human colonic tissue. The relative proportions of mucin species I-VI in tissue explants remained constant throughout a 30-h culture period. However, the proportional representation of the various mucin species in media was significantly different from that found in tissue, which suggests that some mucin species (I, II, and III) are differentially secreted, whereas others (IV and V) are retained within intracellular pools. Radiolabeled precursors were incorporated into mucin species I, II, and III at a 2.0-2.6-fold greater rate than their concentration in tissue, supporting the concept that these glycoproteins were both synthesized and secreted at a greater rate than species IV and V. Colonic mucosal explants from patients with ulcerative colitis showed greater than 90% reduction of species IV. However, the amount of species IV recovered from culture media of ulcerative colitis explants was comparable to normal controls. It appears that mucin species IV is differentially secreted rather than retained within intracellular pools in mucosa of patients with ulcerative colitis.

Cells, Cultured↗