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Biomedical subjects

J Hewett

Publications and source records attributed to J Hewett.

At least 19 recordsLinked to original sources
PubMed1997

Fine localization of the torsion dystonia gene (DYT1) on human chromosome 9q34: YAC map and linkage disequilibrium.

The DYT1 gene, which maps to chromosome 9q34, appears to be responsible for most cases of early-onset torsion dystonia in both Ashkenazic Jewish (AJ) and non-Jewish families. This disease is inherited in an autosomal dominant mode with reduced penetrance (30%-40%). The abnormal involuntary movements associated with this disease are believed to be caused by unbalanced neural transmission in the basal ganglia. Previous linkage disequilibrium studies in the AJ population placed the DYT1 gene in a 2-cM region between the loci D9S62a and ASS. A YAC contig has now been created spanning 600 kb of this region including D9S62a. The location of the DYT1 gene has been refined within this contig using several new polymorphic loci to expand the linkage disequilibrium analysis of the AJ founder mutation. The most likely location of the DYT1 gene is within a 150 kb region between the loci D9S2161 and D9S63.

Adult↗
PubMed1995

The hydroxylation of omeprazole correlates with S-mephenytoin metabolism: a population study.

We compared omeprazole and mephenytoin as probes for the CYP2C19 metabolic polymorphism. Single oral doses of omeprazole (20 mg) or mephenytoin (100 mg) were administered at least 1 week apart to 167 healthy volunteers. Mephenytoin metabolism was measured using the amount of 4'-hydroxymephenytoin and the S/R ratio of mephenytoin in an 8-hour urine collection. Omeprazole hydroxylation was measured using the ratio of omeprazole to 5'-hydroxyomeprazole in serum 2 hours after dosing. All three methods separated poor- or extensive-metabolizer phenotypes with complete concordance. Omeprazole hydroxylation correlated with the S/R ratio of mephenytoin in extensive metabolizers (r2 = 0.681; p < 0.001). Genotyping tests showed that six poor metabolizers of omeprazole were homozygous for a single base pair mutation in exon 5 of CYP2C19. These results support the hypothesis that omeprazole 5'-hydroxylation cosegregates with the CYP2C19 metabolic polymorphism.

Adult↗
PubMed1995

Comparing clinical vocabularies using coding system fidelity.

Much effort has been directed toward the development of an ideal multipurpose controlled medical vocabulary for use in human and veterinary medicine. SNOMED International is one effort that has resulted in a larger and more complex nomenclature system. Although it was able to code more concepts, SNOMED International failed to statistically improve vocabulary fidelity when compared with the 30+ year old SNVDO vocabulary. We found that SNOMED has a lower intercoder consistency than SNVDO and that a greater number of codes were necessary to represent an individual concept. Our study shows a significant Coder-Vocabulary interaction which suggests that more emphasis should be placed on coding guidelines and coder training. Clinician data entry and coding may be necessary for maximum vocabulary fidelity.

Abstracting and Indexing↗
PubMed1994

Weather, beliefs about weather, and disease severity among patients with fibromyalgia.

OBJECTIVE: This investigation 1) examined the relationships among actual weather, disease severity, and symptoms for individuals with fibromyalgia, 2) assessed subjects' beliefs about weather affecting their symptoms, and 3) examined differences between individuals with high and low "weather sensitivity." METHODS: Eighty-four individuals meeting Yunus' criteria for the diagnosis of fibromyalgia participated. Subjects completed the Weather and Pain Questionnaire (WPQ), the Arthritis Impact Measurement Scales (AIMS), the Symptom Checklist-90-Revised (SCL-90-R), and a Visual Analog Scale (VAS) assessing pain. A tender point index and a myalgic score were also obtained. RESULTS: Subjects reported that weather affected musculoskeletal symptoms predominantly. The strongest relationship was found between weather beliefs and self-reported pain scores. Subjects with high weather sensitivity tended to have more functional impairment and psychological distress.

Activities of Daily Living↗
PubMed1994

Pharmacogenetic characteristics of the eosinophilia-myalgia syndrome.

This study tested the hypothesis that patterns of xenobiotic metabolism in patients with eosinophilia-myalgia syndrome (EMS) differed from healthy control subjects. We determined the genotypes of 27 EMS patients with EMS and 114 control subjects for the cytochrome P450 CYP2D6 polymorphism. The metabolic phenotypes of patients with EMS for S-mephenytoin hydroxylation (n = 17) and dapsone acetylation (n = 19) were determined and compared with 29 healthy control subjects. The incidence of the CYP2D6 poor metabolizer genotype (mutant/mutant) was 0.185 in patients with EMS and 0.061 in control subjects (Mantel-Haenszel, chi 2 = 7.213, p = 0.007). The mephenytoin S/R ratios were 0.39 +/- 0.23 in patients with EMS versus 0.18 +/- 0.13 in control subjects (p < or = 0.005). There was no difference in dapsone acetylation between the two groups. A pattern of xenobiotic metabolism may play a role in the pathogenesis of EMS, but the precise role that it plays remains unclear.

Alleles↗
PubMed1994

Assessing anger expression in children and adolescents.

Anger expression styles are associated with psychological and physical well-being among adults. Little is known about the role of anger expression in children's functioning. This lack of knowledge has resulted, in part, from a lack of validated tools for anger expression measurement. The Pediatric Anger Expression Scale-3rd edition (PAES-III; Jacobs, Phelps, & Rohrs, 1989; Jacobs & Kronaizl, 1991) has been proposed as a reliable and valid assessment instrument of anger expression styles. The PAES-III includes three scales that measure anger turned inward, anger expressed outwardly, and anger controlled cognitively or behaviorally. We evaluated the psychometric properties of this instrument when it is administered verbally to children with juvenile rheumatoid arthritis, children with juvenile diabetes mellitus, and healthy children. Internal consistency was adequate for anger-in and anger-out, but marginal for anger-control. Concurrent validity was supported for the total sample. A principal components analysis suggested a four-factor model of anger expression. Overall, the PAES-III was found to have psychometric limitations. Use of a modified PAES-III may facilitate pediatric behavioral medicine research addressing risk factors for maladjustment among children with chronic illnesses.

Adaptation, Psychological↗
PubMed1994

The DYT1 gene on 9q34 is responsible for most cases of early limb-onset idiopathic torsion dystonia in non-Jews.

Idiopathic torsion dystonia (ITD) is characterized by involuntary twisting movements and postures. A gene for this disorder, DYT1, was mapped to chromosome 9q34 in 12 Ashkenazi Jewish (AJ) families and one large non-Jewish kindred. In the AJ population, strong linkage disequilibrium exists between DYT1 and adjacent markers within a 2-cM region. The associated haplotype occurs in > 90% of early limb-onset AJ cases. We examined seven non-Jewish ITD families of northern European and French Canadian descent to determine the extent to which early-onset ITD in non-Jews maps to DYT1. Results are consistent with linkage to the DYT1 region. Affected individuals in these families are clinically similar to the AJ cases; i.e., the site of onset is predominantly in the limbs and at least one individual in each pedigree had onset before age 12 years. None carries the AJ haplotype; therefore, they probably represent different mutations in the DYT1 gene. The two French Canadian families, however, display the same haplotype. Estimates of penetrance in non-Jewish families range from .40 to .75. We identified disease gene carriers and, with adjustments for age at onset, obtained a direct estimate of penetrance of .46. This is consistent with estimates of 30%-40% in the AJ population. Two other non-Jewish families with atypical ITD (later onset and/or cranial or cervical involvement) are not linked to DYT1, which indicates involvement of other genes in dystonia.

Adolescent↗
PubMed1992

A randomized, double-blind, placebo-controlled trial to evaluate the effect of enalapril in patients with clinical diabetic nephropathy.

It is unknown if the antiproteinuric effect of angiotensin-converting enzyme (ACE) inhibitors reflects attenuation in the rate of progression of diabetic nephropathy. We report the results of a randomized, double-blind clinical trial designed to evaluate the longitudinal (18-month) effect of the ACE inhibitor, enalapril (5 to 40 mg/d), versus a placebo on 24-hour urinary protein excretion and on the rate of progression of renal disease in 33 patients with clinical diabetic nephropathy. Systemic blood pressure was controlled throughout the trial with conventional antihypertensive drugs. Glomerular filtration rate (GFR), determined by Tc99mDTPA renal clearance, and urinary protein excretion were monitored at 3-month intervals. Enalapril, in contrast to placebo therapy, was associated with an initial (40%) and sustained (33%) decrease in urinary protein excretion. Patients randomized to both enalapril or placebo experienced mean decreases in GFR, from 1.01 mL/s/1.73 m2 (61 mL/min/1.73 m2) to 0.85 mL/s/1.73 m2 (51 mL/min/1.73 m2), and from 1.06 mL/s/1.73 m2 (64 mL/min/1.73 m2) to 0.97 mL/s/1.73 m2 (58 mL/min/1.73 m2), respectively. Eleven of 18 patients (61%) randomized to enalapril, and 10 of 15 (66%) patients randomized to placebo, had a decrease in GFR; their rates of progression were -1.18 mL/min/1.73 m2/mo and -1.00 mL/min/1.73 m2/mo, respectively. In the absence of changes in blood pressure, the addition of an ACE inhibitor to patients with clinical diabetic nephropathy could not be shown to confer a unique renal protective effect. A prolonged decrease in 24-hour protein excretion could not be shown to predict attenuation in the progression of established clinical diabetic nephropathy.

Adult↗
PubMed1992

Relationship of changes in helplessness and depression to disease activity in rheumatoid arthritis.

We investigated the relationship between changes in helplessness and depression to disease activity in rheumatoid arthritis (RA). Sixty-three men with RA were examined at baseline, 3 months, and 6 months. Joint counts, immunophenotypic analyses of peripheral blood lymphocytes, and measures of psychological status were obtained at each examination. Zero-order correlations between psychological change and disease activity change from baseline to 6 months were not significant, but hierarchical multiple regression analyses revealed that changes in affective state were significantly related to joint counts at 6 months. Additionally, changes in absolute numbers of HLA-DR+ (human leukocyte antigen DR type) cells were significantly related to joint counts at 6 months. When absolute numbers of HLA-DR+ cells were entered prior to affective state in a hierarchical multiple regression, affective state was only marginally statistically significant. The study shows that longitudinal relationships between affective changes and disease activity are moderated by intervening variables such as immunologic activation.

Aged↗
PubMed1991

Adjustment to spinal cord injury: stage theory revisited.

To better understand adjustment following spinal cord injury (SCI), 106 subjects from two samples (N = 53 each) were administered the SCL-90-R, a symptom checklist, and the Multidimensional Health Locus of Control scales. Sample 1 subjects were admitted for rehabilitation during 1981 to 1982 and sample 2 subjects were admitted during 1984 to 1986. Sample 2 subjects entered rehabilitation programs more quickly after injury and reported more anxiety, phobic anxiety, and hostility than sample 1 subjects. Within each sample, there was no evidence for a relationship between age or time since injury and health beliefs or psychological distress. This study does not support stage theory for adjustment after catastrophic injury, but does suggest the importance of understanding the impact of social policy changes in adjustment following spinal cord injury.

Adaptation, Psychological↗
PubMed1991

Assessment of physician perceptions on the fatality of cancer.

A questionnaire was developed to evaluate internists' perceptions about patients' survival of cancer as compared with other diseases. The questionnaire consisted of four pairs of survival-matched cancer and non-cancer diseases. The questionnaire was administered to 42 faculty members and 37 resident physicians in the Department of Medicine at the University of Missouri-Columbia. Physicians rated patients' survival of cancer to be significantly lower than patients' survival of comparable non-cancer diseases (p less than 0.001). Resident physicians estimated patients' survival of breast cancer to be significantly lower (p less than 0.007) and estimated the survival of lung cancer to be significantly higher than the faculty members' estimate (p less than 0.003). These physicians' perceptions could adversely affect the quality of care and the degree of consideration given to both cancer and non-cancer patients. The differences observed in faculty members' and resident physicians' responses were attributed to the greater knowledge and clinical experience of faculty rather than differences in attitudes toward cancer.

Health Knowledge, Attitudes, Practice↗
PubMed1989

Reduction of spiral ganglion neurons in the aging canine with hearing loss.

The middle and inner ears of 16 dogs, from 1.5 to 17 years of age, with differing degrees of suspected hearing loss were examined. Auditory function was assessed subjectively, and electrophysiologically by recording brainstem auditory-evoked responses (BAER) to click stimuli. Ossicular chains and stapediovestibular articulations were evaluated macroscopically and by light microscopy for evidence of bony ankylosis; no abnormalities were found. A determination of spiral ganglion packing density revealed a loss of spiral ganglion cells in all areas of the cochlea in dogs of the deaf group and in the upper and lower basal region of dogs from the hearing impaired group. The largest losses of spiral ganglion cells in the deaf group were located in the upper and lower basal region. The deaf group's density was reduced to 44% (upper basal) 15% (lower basal) of the normal hearing group. The largest spiral ganglion cell loss for dogs in the hearing impaired group occurred in the lower basal region where the density was reduced to 40% of the normal hearing group. These morphological findings in the aging canine are consistent with a peripheral nerve hearing loss.

Aging↗
PubMed1987

Electrophysiologic testing in patients with unexplained syncope: clinical and noninvasive predictors of outcome.

To assess whether the level of risk of having significant electrophysiologic abnormalities can be determined, 29 clinical variables were analyzed in 104 patients with unexplained syncope who underwent electrophysiologic testing. A positive electrophysiologic study was defined as: a sinus node recovery time greater than or equal to 3 seconds; HV interval greater than or equal to 100 ms; infranodal block during atrial pacing; unimorphic ventricular tachycardia; and supraventricular tachycardia associated with hypotension. Thirty-one patients had a positive study, with inducible ventricular tachycardia being the most common finding (71% of positive studies). A left ventricular ejection fraction less than or equal to 0.40 was the most powerful predictor of a positive electrophysiologic study (p less than 0.00001), followed by the presence of bundle branch block (p less than 0.00003), coronary artery disease (p less than 0.0003), remote myocardial infarction (p less than 0.00006), use of type 1 antiarrhythmic drugs (p less than 0.00003), injury related to loss of consciousness (p less than 0.01) and male sex (p less than 0.01). A negative electrophysiologic study was associated with an ejection fraction greater than 0.40 (p less than 0.00001), the absence of structural heart disease (p less than 0.00001), a normal electrocardiogram (ECG) (p less than 0.0001) and normal ambulatory ECG monitoring (p less than 0.0001). The probability of a negative study increased as the number and duration of syncopal episodes increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Purification of prealbumin from human serum.

A method is presented by which prealbumin (thyroxine-binding prealbumin; tryptophan-rich prealbumin) may be purified to homogeneity from human serum. The method involves precipitation of contaminating proteins with dilute aqueous phenol, ion-exchange chromatography on DEAE-Sephacel, and gel permeation chromatography on Sephadex G-100. The yield is 25-30%, and the prealbumin is homogeneous by polyacrylamide gel electrophoresis at pH 8.9 and pH 3.6.

Chemical Precipitation↗
PubMed1980

Quantitative ultrastructural analysis of the human parietal cell during acid inhibition and increase of gastric potential difference by glucagon.

Glucagon inhibits gastric acid secretion and increases the negativity of gastric mucosal potential difference (PD) in man. To test the hypothesis that the increased negativity of PD after glucagon in man could be due to decreased parietal cell canalicular membrane area, a quantitative ultrastructural analysis was carried out. Four healthy volunteers with normal gastric mucosa were submitted to biopsy before and 20 minutes after intravenous injection of 2 mg glucagon (G). This time corresponded with the maximal change in PD and a decrease in gastric acid secretion. Canalicular and tubulovesicular membrane area of 80 parietal cells (40 cells before glucagon and 40 cells after glucagon) were quantified by the Loud morphometric method. After glucagon, the oxyntic cell canalicular membrane area was reduced by one-fourth (P less than 0.05), while tubulovesicular membrane area showed an increase (P less than 0.05) at the same time. The decrease in the area of parietal cell canalicular membrane caused by glucagon may in part be responsible for increased negativity of the gastric PD caused by this hormone.

Adult↗
PubMed1980

Human upper esophageal sphincter pressure profile.

The pressure profile of the upper esophageal sphincter was characterized in nine normal subjects. Directionally oriented intraluminal pressures were recorded, at 0.5-cm intervals over a 6-cm segment that encompassed the sphincter, by a high-fidelity low-compliance recording system. The peak resting pressure was directed posteriorly, and the lowest pressures were recorded from the lateral orientations. Significant axial asymmetry was observed with peak posterior pressure 0.55 cm more distal than the anterior pressure. Calculations of variability of pressures recorded at each interval showed the peak pressure to be the most reproducible measurement for each subject. Isotonic saline and acid infusions into the esophagus distal to the sphincter resulted in increased sphincteric peak resting pressure (acid greater than saline). There was axial lengthening of the sphincteric pressure zone with infusion of acid and saline, but this observed increase in length was not significant except at the 50 mmHg level. Pressure profiles recorded during 0.5-cm station pull-throughs were virtually identical to those obtained by a rapid continuous pull-through technique.

Adult↗