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L S Schwartz

Publications and source records attributed to L S Schwartz.

At least 19 recordsLinked to original sources
PubMed1992

Sequence and genomic structure of the human adult skeletal muscle sodium channel alpha subunit gene on 17q.

The amino acid sequence of the sodium channel alpha subunit from adult human skeletal muscle has been deduced by cross-species PCR-mediated cloning and sequencing of the cDNA. The protein consists of 1836 amino acid residues. The amino acid sequence shows 93% identity to the alpha subunit from rat adult skeletal muscle and 70% identity to the alpha subunit from other mammalian tissues. A 500 kb YAC clone containing the complete coding sequence and two overlapping lambda clones covering 68% of the cDNA were used to estimate the gene size at 35 kb. The YAC clone proved crucial for gene structure studies as the high conservation between ion channel genes made hybridization studies with total genomic DNA difficult. Our results provide valuable information for the study of periodic paralysis and paramyotonia congenita, two inherited neurological disorders which are caused by point mutations within this gene.

Adult↗
PubMed1992

Fluorescent multiplex linkage analysis and carrier detection for Duchenne/Becker muscular dystrophy.

We have developed a fast and accurate PCR-based linkage and carrier detection protocol for families of Duchenne muscular dystrophy (DMD)/Becker muscular dystrophy (BMD) patients with or without detectable deletions of the dystrophin gene, using fluorescent PCR products analyzed on an automated sequencer. When a deletion is found in the affected male DMD/BMD patient by standard multiplex PCR, fluorescently labeled primers specific for the deleted and nondeleted exon(s) are used to amplify the DNA of at-risk female relatives by using multiplex PCR at low cycle number (20 cycles). The products are then quantitatively analyzed on an automatic sequencer to determine whether they are heterozygous for the deletion and thus are carriers. As a confirmation of the deletion data, and in cases in which a deletion is not found in the proband, fluorescent multiplex PCR linkage is done by using four previously described polymorphic dinucleotide sequences. The four (CA)n repeats are located throughout the dystrophin gene, making the analysis highly informative and accurate. We present the successful application of this protocol in families who proved refractory to more traditional analyses.

DNA↗
PubMed1991

A Met-to-Val mutation in the skeletal muscle Na+ channel alpha-subunit in hyperkalaemic periodic paralysis.

HYPERKALAEMIC periodic paralysis (HYPP) is an autosomal dominant disease that results in episodic electrical inexcitability and paralysis of skeletal muscle. Electrophysiological data indicate that tetrodotoxin-sensitive sodium channels from muscle cells of HYPP-affected individuals show abnormal inactivation. Genetic analysis of nine HYPP families has shown tight linkage between the adult skeletal muscle sodium channel alpha-subunit gene on chromosome 17q and the disease (lod score, z = 24; recombination frequency 0 = 0), strongly suggesting that mutations of the alpha-subunit gene cause HYPP. We sequenced the alpha-subunit coding region isolated from muscle biopsies from affected (familial HYPP) and control individuals by cross-species polymerase chain reaction-mediated complementary DNA cloning. We have identified an A----G substitution in the patient's messenger RNA that causes a Met----Val change in a highly conserved region of the alpha-subunit, predicted to be in a transmembrane domain. This same change was found in a sporadic case of HYPP as a new mutation. We have therefore discovered a voltage-gated channel mutation responsible for a human genetic disease.

Amino Acid Sequence↗
PubMed1991

A biopsychosocial treatment approach to the management of diabetes mellitus.

The relationship among recent life stress, social support, a patient's locus of control, and the control of blood glucose is evaluated in persons with diabetes mellitus, using objective measures of these psychosocial variables. Short-term [fasting blood sugar (FBS)] and long-term [glycosylated hemoglobin (Hgb A-1C)] control measures are taken at two points in time in order to evaluate the effects of the psychosocial variables on change in diabetes control. For life events, a significant positive association was found between the number of recent life events and blood glucose control. Decrease in social support predicted a worsening of longer-term (Hgb A-1C) control over time. An external locus of control within the patient was associated both with poor short-term control at time one and prediction of poorer long-term control over time. The implications of these findings are discussed in support of a biopsychosocial approach to the management of diabetes mellitus.

Blood Glucose↗
PubMed1989

Attitudes of mental health professionals toward alcoholism recognition and treatment.

The attitudes of 100 urban mental health professionals toward alcoholism diagnosis and treatment were assessed using a 23-item questionnaire. A significant number of those sampled, physicians more than other professional groups, looked upon alcoholism as a disease in its own right. Physicians, attendings more than residents, subscribed to a more medical history-taking model. While the majority of those surveyed would advise complete sobriety, a large number would not. Likewise, despite a large percentage of our sample who indicated familiarity with alcohol-related concepts, a significant number did not. Referral to Alcoholics Anonymous was highly endorsed by those advocating sobriety. The meaning of these findings is discussed in relation to the marked improvement noted in professionals' attitudes toward alcoholic patients. Based on these findings, methods of further improving the clinician's awareness of alcoholism are considered.

Adult↗
PubMed1988

A biopsychosocial approach to the management of the diabetic patient.

Among the psychosocial variables to be considered by the primary care physician in dealing with a diabetic patient are the effects of stressful life events, social support, and the patient's locus of control. Literature relevant to each of these is explored. A practical approach is discussed for the primary care doctor to consider in utilizing these psychosocial variables in diabetes management.

Diabetes Mellitus↗
PubMed1986

The role of recent life events and social support in the control of diabetes mellitus. A pilot study.

This study evaluated objectively the relationship between recent life events, social support systems, and blood glucose control in diabetic patients using both short-term [fasting blood sugar (FBS)] and long-term [glycosylated hemoglobin (Hgb A-1C)] measures of control. We found that a higher number of life events was associated with a higher percentage of abnormal FBS and Hgb A-1C results, and that improved social support was associated with a smaller percentage of abnormal Hgb A-1C scores. These pilot findings are discussed in connection with a biopsychosocial approach to the understanding and management of diabetes mellitus.

Adult↗
PubMed1986

A supportive care clinic: maintaining the chronic psychiatric patient.

A comprehensive investigation into the social support networks of a group of chronic psychiatric patients attending a Supportive Care Clinic was conducted. The results suggest that these patients, while exhibiting weaker support systems than the general population, do have a significant amount of personal support in addition to that received from the treatment center. Furthermore, they perceive the "support" aspect of the Clinic as the most helpful feature as compared to personal growth or medication. The results of these findings are discussed in terms of their practical utility for the ambulatory care of chronic psychiatric patients.

Adult↗