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Biomedical subjects

J Livingston

Publications and source records attributed to J Livingston.

34 records · Page 2Linked to original sources
PubMed1994

Evaluation of the Cerebro Trac 2500 for monitoring of cerebral function in the neonatal intensive care.

Assessment of brain function is important in predicting long term outcome in sick neonates thus stimulating increasing interest in methods of cerebral surveillance. A report using the Cerebro Trac 2500 in adult intensive care suggested this monitor may provide more information about ongoing cerebral activity than the Cerebral Function Monitor (CFM). Simultaneous recordings in a cross-section of the neonatal population were obtained with multichannel EEG monitor, CFM and Cerebro Trac. Both conventional EEG and CFM determined changes in sleep states and background activity. Seizures of greater than 30 seconds duration were detected by both analyzing monitors, although shorter duration transients were not apparent. Despite the apparent similarity in fixed filters in both CFM and Cerebro Trac, the Cerebro Trac seemed to filter out the lower frequencies that can predominate in the neonatal EEG. The Cerebro Trac did not confer any advantage over the CFM for neonatal cerebral surveillance.

Brain↗
PubMed1993

Isolation of a partial candidate gene for Menkes disease by positional cloning.

Menkes disease is an X-linked recessive disorder of copper metabolism resulting in death in early infancy. The gene has been mapped to band Xq13 based, in part, on a translocation breakpoint in a female with the disease, which was found to lie within 300 kilobases (kb) of the PGK-1 locus, allowing the isolation of a YAC clone spanning the breakpoint. Phage subclones from the breakpoint region were isolated and used to screen cDNA libraries. cDNA clones were found which detect an 8 kb transcript from normal individuals but show diminished or absent hybridization in Menkes disease patients. Partial sequence of the cDNA shows a unique open reading frame containing putative metal binding motifs which have been found in heavy metal resistance genes in bacteria. This gene is a strong candidate for the Menkes disease gene.

Adenosine Triphosphatases↗
PubMed1993

Glycosylation of Asn397 or Asn418 is required for normal insulin receptor biosynthesis and processing.

Two N-linked sites of glycosylation in the insulin receptor were examined for their contribution to insulin binding, tyrosine kinase activity, and receptor biosynthesis. Asn397 and Asn418 were replaced by Gln using site-directed mutagenesis either as single mutations, i.e., Q-397 and Q-418, or as a double mutation in which both sites were removed (Q-D). The mutations were transiently expressed in COS cells and the findings compared with cells that transiently expressed the wild-type human insulin receptor. Q-397 and Q-418 mutant insulin receptors had insulin-binding characteristics similar to the wild-type human insulin receptor, whereas no insulin-binding activity could be detected above the control level in cells transfected with Q-D. Flow cytometry with antibodies against the human insulin receptor indicated the presence of Q-397, Q-418, and wild-type human insulin receptors in the surface of COS cells and failed to demonstrate a Q-D receptor. Insulin-induced autophosphorylation was similar in Q-397, Q-418, and wild-type human insulin receptors as was their ability to phosphorylate an artificial substrate, poly Glu-Tyr (4:1). Our inability to detect Q-D receptors was not caused by a lack of Q-D mRNA. COS cells transfected with Q-D cDNA generated as much Q-D mRNA as the amount of wild-type human insulin receptor mRNA present in cells transfected with wild-type receptor cDNA. Finally, pulse-chase experiments with [35S]Met were able to detect 190,000-M(r) proreceptors and the alpha-subunits for Q-397, Q-418, and wild-type human insulin receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1991

Diffuse cortical dysplasia, or the 'double cortex' syndrome: the clinical and epileptic spectrum in 10 patients.

Diffuse neuronal migration disorders associated with epilepsy can now be recognized by modern neuroimaging techniques, particularly high-resolution MRI. We report 10 patients with a recently described MRI picture of continuous or generalized band heterotopia underlying the cortical mantle, giving the appearance of a "double cortex." They have epilepsy, and almost all have mental retardation. The epileptic disorder varies in nature and degree of severity. Patients may present with infantile spasms, a Lennox-Gastaut syndrome, or other forms of secondary generalized or multifocal epilepsy. Response to medical treatment is variable. Callosotomy may lead to considerable reduction of drop attacks, present in 60%. Mental retardation is usually mild or moderate, and only rarely severe. It correlates with the type of epileptic syndrome, and is greater in patients with more disorganized cortex overlying the heterotopia. Recognition of this entity by MRI is important for appropriate diagnosis of the epileptic disorder, planning of therapeutic strategy, and prognosis.

Adolescent↗
PubMed1990

Pre-eclampsia is associated with HLA-DR4 sharing between mother and fetus.

Full HLA-A,B and DR typing was carried out on 92 women with proteinuric pre-eclampsia, 80 of their husbands and 46 of their babies. The results were compared with corresponding data from 65 normotensive pregnancies involving primiparous women. The frequency of HLA-DR4 was increased in the pre-eclamptic women (RR 3.1; p less than 0.005) and in the babies of pre-eclamptic pregnancies (RR 2.6; p less than 0.03). The strongest association, however, was with sharing of HLA-DR4 between mother and fetus (RR 4.2; p = 0.01). There was no increase in HLA antigen sharing in general between spouses or maternal-fetal pairs in pre-eclampsia. Nor did pre-eclamptic women exhibit increased homozygosity in general at any HLA locus. We conclude that genetic susceptibility to pre-eclampsia depends at least partly on fetomaternal compatibility for a gene or genes associated with HLA-DR4.

Female↗
PubMed1989

SAGE II aerosol data validation based on retrieved aerosol model size distribution from SAGE II aerosol measurements.

This paper describes an investigation of the comprehensive aerosol correlative measurement experiments conducted between November 1984 and July 1986 for satellite measurement program of the Stratospheric Aerosol and Gas Experiment (SAGE II). The correlative sensors involved in the experiments consist of the NASA Ames Research Center impactor/laser probe, the University of Wyoming dustsonde, and the NASA Langley Research Center airborne 14-inch (36 cm) lidar system. The approach of the analysis is to compare the primary aerosol quantities measured by the ground-based instruments with the calculated ones based on the aerosol size distributions retrieved from the SAGE II aerosol extinction measurements. The analysis shows that the aerosol size distributions derived from the SAGE II observations agree qualitatively with the in situ measurements made by the impactor/laser probe. The SAGE II-derived vertical distributions of the ratio N0.15/N0.25 (where Nr is the cumulative aerosol concentration for particle radii greater than r, in micrometers) and the aerosol backscatter profiles at 0.532- and 0.6943-micrometer lidar wavelengths are shown to agree with the dustsonde and the 14-inch (36-cm) lidar observations, with the differences being within the respective uncertainties of the SAGE II and the other instruments.

Aerosols↗
PubMed1986

Studies of the human liver insulin receptor in noninsulin-dependent diabetes mellitus.

The insulin binding characteristics and the structural components of the insulin receptor were studied in the purified liver plasma membranes from seven patients with noninsulin-dependent diabetes (NIDDM) and seven control subjects. In comparison to the controls, diabetic subjects had a 65% reduction in plasma insulin levels in response to an oral glucose load. Specific insulin binding by liver membranes from diabetic patients was, however, twofold greater than the binding activity by membranes from control subjects. This alteration resulted largely from an increase in the number of insulin receptors and a modest increase in receptor binding affinity. Holo (nonreduced) receptor species of similar molecular weights were detected by an affinity labeling technique in the two membrane preparations and sulfhydryl reduction demonstrated an insulin binding subunit of 125,000 mol wt. Overall, these results show that the hepatic insulin resistance of NIDDM cannot be explained by a deficiency in insulin binding.

Diabetes Mellitus, Type 2↗
PubMedDate not supplied

Epidemiology of and surveillance for postpartum infections.

We screened automated ambulatory medical records, hospital and emergency room claims, and pharmacy records of 2,826 health maintenance organization (HMO) members who gave birth over a 30-month period. Full-text ambulatory records were reviewed for the 30-day postpartum period to confirm infection status for a weighted sample of cases. The overall postpartum infection rate was 6.0%, with rates of 7.4% following cesarean section and 5.5% following vaginal delivery. Rehospitalization; cesarean delivery; antistaphylococcal antibiotics; diagnosis codes for mastitis, endometritis, and wound infection; and ambulatory blood or wound cultures were important predictors of infection. Use of automated information routinely collected by HMOs and insurers allows efficient identification of postpartum infections not detected by conventional surveillance.

Ambulatory Care↗
PubMedDate not supplied

In vitro study on capsule formulations of omeprazole containing enteric coated granules.

Omeprazole is a unique and effective agent for suppression of gastric acid secretion. It promises to be especially useful in Zollinger-Ellison Syndrome (1) and in other patients who have failed to respond to H2 antagonist therapy. The dose requirement for zollinger-ellison syndrome (ZES) disease is upto 180 mg per day. The drug omeprazole shows biological half life of 2-3 hours. (2) Considering its proven therapeutic efficacy for ZES disease, this study is attempted to formulate sustained release capsule containing enteric coated granules. For formulating sustained release drug delivery system immediate release dose (IR) is calculated as 10 mg of drug and sustained release dose (SR) is taken as 50 mg. (3) The polymers used for retarding the release are Ethyl Cellulose (EC) and Hydroxy Propyl Methyl Cellulose (HPMC). Solvent evaporation technique is followed to prepare sustained release granules. Granules are finally coated with enteric coating of Suteric (Polyvinly acetate phthalate, PVAP). Thus the eight capsule formulations are prepared and formulation found very close to theoretical sustained release (TSR) according to in vitro study (4) is subjected to stability studies. Results show that product should be stored at room temperature or below ambient temperature.

Anti-Ulcer Agents↗