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Biomedical subjects

M Schulman

Publications and source records attributed to M Schulman.

36 records · Page 2Linked to original sources

Handedness patterns in autism suggest subtypes.

The present study reports preliminary data from two unselected samples of carefully diagnosed autistic subjects (children and adults) and an assessment procedure that includes a large sample of items, appropriate for lower-functioning autistic subjects, with multiple presentations within and between sessions 1 week apart. The study seeks to determine (1) whether a raised incidence of non-right-handedness exists in these samples (2) if so, what constructs best represent this shift in the handedness distribution (i.e., phenotype and CNS substrate) and (3) whether these handedness phenotypes are associated with different levels of cognitive functioning. The results reveal a dramatic shift away from right-handedness in both autistic samples, due to a raised incidence of two phenotypes, manifest left-handedness and ambiguous handedness. The ambiguously handed, who were postulated to represent substantial bilateral CNS pathology due to early brain injury, were found to have much lower intellectual scores in one of the study samples.

Adolescent↗

Female self-report and autonomic responses to sexually pleasurable and sexually aversive readings.

This study was designed to investigate possible differential autonomic responses to sexually pleasurable and sexually aversive readings. Reading conditions were counterbalanced so that an equal number of subjects received both orders of the two readings. Female subjects' ratings, skin conductance (SC), finger pulse (FP), and heart rate (HR), in response to these readings were compared. The sexually pleasurable as compared to the sexually aversive passage was rated as more sexually stimulating, less anxiety and guilt provoking, and less disgusting, but as equally well portrayed and interesting (extent of boredom). While essentially equal SC increases were noted in response to both readings, HR deceleration and vasodilation were more characteristic of the response to the sexually pleasurable passage. These findings were compared within the context of preexperimental setting conditions and were interpreted in terms of Lacey's intake-rejection hypothesis. These findings are consistent with the idea that pleasurable sexual readings are associated with interest, attention, and heart rate deceleration, whereas aversive material may be related to rejection of the material and to heart rate acceleration.

Arousal↗

Kinetics and catalytic properties of coenzyme A transferase from Peptostreptococcus elsdenii.

Coenzyme A (CoA) transferase from Peptostreptococcus elsdenii was purified to homogeneity, and some of its physical and catalytic properties were determined. The native enzyme has a molecular weight of 181,000 and is composed of two alpha subunits (molecular weight, 65,000) and one beta subunit (molecular weight 50,000). Heat treatment of the crude cell extract to 58 degrees C causes proteolysis of the native enzyme and yields a catalytically active enzyme with an approximate molecular weight of 120,000. The native CoA transferase is specific for CoA esters of short-chain alkyl monocarboxylic acids. With acetate as CoA acceptor the enzyme is active with propionyl-, butyryl-, isobutyryl-, valeryl-, isovaleryl,- and hexanoyl-CoA but not with heptanoyl or longer-chain CoA esters. There is no activity with acetoacetyl-CoA or the CoA esters of dicarboxylic acids. Steady-state kinetics indicated that the reaction proceeds via a classical bi-, bi-ping-pong mechanism. Maximal activity is obtained with propionyl- or butyryl-CoA, and both the Vmax and Km decrease as the alkyl chain length of the CoA ester increases. All CoA esters apompetitive inhibitor although it is not active as a substrate. Evidence for an enzyme CoA intermediate was provided by demonstration of an exchange between 14C-free acids (acetate and butyrate) and their corresponding CoA esters and by isolation of a 3H-labeled CoA enzyme after incubation of the enzyme with 3H-labeled acetyl-CoA. Approximately 2 mol of CoA was bound per mol of enzyme.

Binding Sites↗

Total synthesis of acetate from CO 2 . V. Determination by mass analysis of the different types of acetate formed from 13 CO 2 by heterotrophic bacteria.

Mass analysis was used to determine the amount of acetate which is totally synthesized from (13)CO(2) during fermentations by Clostridium formicoaceticum, C. acidiurici, C. cylindrosporum, Butyribacterium rettgeri, and Diplococcus glycinophilus. In the fermentation of fructose by C. formicoaceticum, 27% of the acetate was found to be totally synthesized from CO(2), and the remaining acetate was unlabeled, having been formed from fructose. Evidence is presented that the purine-fermenting organisms, C. acidiurici and C. cylindrosporum, totally synthesized about 9% of the acetate from CO(2), and that the methyl group of an additional 9% was formed from CO(2). The remaining acetate was formed from the carbons of the purine and not via CO(2). It has been postulated that the fermentation of the purines and synthesis of acetate from CO(2) both occur via derivatives of tetrahydrofolate. Evidence is presented that a compartmentalization of these folate intermediates is required if both the purine degradation and the CO(2) utilization involve identical intermediates. Neither B. rettgeri nor D. glycinophilus incorporated sufficient (13)CO(2) into acetate to allow determination of the types of acetate by mass analysis, although they did incorporate labeled (14)CO(2) in both positions of acetate.

Acetates↗

Characteristics associated with successful weaning in ventilator-dependent preterm infants.

Eighteen ventilator-dependent preterm infants with hyaline membrane disease were studied for 24 hours before and after an attempt at extubation. All were treated with theophylline prior to weaning and achieved average levels of 8.9 +/- 1.7 micrograms/ml (49 +/- 9 mumol/liter) in 13 successfully weaned infants and 8.4 +/- 1.1 micrograms/ml (47 +/- 6 mumol/liter) in 5 infants not extubated, p > 0.05. Infants successfully weaned were significantly (p < 0.01) older, more mature (29 +/- 1 versus 26 +/- 2 weeks' gestational age) and heavier (1107 +/- 236 versus 1016 +/- 256 gm) than infants not successfully extubated. Infants successfully weaned differed only in developing a greater maximal inspiratory force (33.8 +/- 12.3 versus 23.3 +/- 15.0 cm H2O) and higher compliance (1.1 +/- 0.3 versus 0.7 +/- 0.3) during the preweaning treatment period. These results indicate that maturity and size play a significant role in the ability to wean a preterm infant from the ventilator successfully, that maximal inspiratory force and compliance are higher in preterm infants who can be successfully extubated, and that methylxanthines do not uniformly improve pulmonary function in all potentially extubatable preterm infants.

Humans↗

Absence of lower extremity ossification centers in term infants with congenital syphilis.

Radiologic evaluation is valuable for confirmation of congenital syphilis. Bony abnormalities are thought to be secondary to active disease or a growth response of bone to systemic illness. Anteroposterior lower extremity radiographs of 85 euthyroid term infants (> or = 38 weeks' gestation; mean weight, 3244 gm; range, 1940-4380 gm) with presumptive congenital syphilis were evaluated for the presence of the distal femoral and proximal tibial secondary ossification centers and other bony abnormalities. Both proximal tibial and distal femoral ossification centers were absent in only 9 of 85 infants with syphilis; the proximal tibial center was absent in 26 of 85 (total 30.6%; 95% confidence limits 0.2 to 0.4). This observation is significant at the p < 0.01 level by chi-square analysis with use of historical controls. Periosteal new bone formation was seen in 2 of 85 infants. Metaphyseal lucent bands were present in 21 of 85 infants, 8 of whom also had absent lower extremity ossification centers. For comparison we reviewed lower extremity radiographs from 12 term infants without congenital syphilis. Ossification centers were absent in one growth-retarded infant, and metaphyseal lucent bands were found in one infant. Although standard texts report nearly universal ossification of the distal femoral epiphysis at term, we observed delayed skeletal maturation in 30.1% of term infants with congenital syphilis. We speculate that this delay may be reflective of systemic infection.

Chi-Square Distribution↗

Topical anesthesia for line insertion in very low birth weight infants.

OBJECTIVE: This pilot study was designed to assess the impact of topical lidocaine and prilocaine cream on the pain response of very low birth weight infants undergoing percutaneous central venous line insertion. STUDY DESIGN: Infants were randomly assigned to receive 1 to 1.25 gm of the topical anesthetic or to receive zinc oxide placebo 1 hour before line insertion. Investigators blinded to treatment group assignment obtained serial measurements of heart rate, respiratory rate, systolic blood pressure, and oxygen saturation by pulse oximetry. Toxicity from lidocaine was assessed by clinical parameters, and toxic effects from prilocaine were assessed by methemoglobin levels (normal range 0% to 4%). RESULTS: Hearts rates increased significantly during line insertion in controls (n = 6) but not in treated patients (n = 7). Respiratory rates and blood pressure values increased significantly during line insertion in both groups. Oxygen saturation did not change significantly in either group. The percent of increase in heart and respiratory rates from baseline was attenuated in the treated patients compared with controls. Methemoglobin levels were 0.3% to 2.0% for the treated group and 0.3% to 0.7% for controls. CONCLUSION: The topical lidocaine and prilocaine cream application attenuated the lability of vital signs during line insertion in very low birth weight infants, with no evidence of toxicity.

Anesthesia, Local↗