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Biomedical subjects

J Brown

Publications and source records attributed to J Brown.

At least 541 records · Page 30Linked to original sources
PubMed1994

Use of hepatobiliary scintigraphy in clinically normal cats.

Hepatobiliary scintigraphy provides a noninvasive assessment of hepatobiliary structure and function, and has been used extensively in people. Hepatocellular measurements determined in the cats of this study include cardiac washout (< or = 2 minutes) and time of maximal hepatic activity (< or = 5 minutes) and hepatic washout (< or = 30 minutes). The gallbladder response to synthetic cholecystokinin was determined to be < or = 3 minutes. Additional measurements also were identified. Potential use of hepatobiliary scintigraphy in feline medicine is discussed.

Animals↗
PubMed1994

The genetics of Alzheimer's disease.

The discovery of pathogenic mutations in the amyloid precursor protein gene in families with Alzheimer's disease is a major advance in the understanding of the pathogenesis of Alzheimer's disease. In certain families at least, beta-amyloid metabolism plays a central role in the disease process. It is tempting to speculate that beta-amyloid is common to the majority of Alzheimer cases. In the immediate future the discovery of the mutations responsible for the condition in those families that show linkage to chromosomes 14 and 19 will enable it to be established whether beta-amyloid is involved in these pedigrees as well. If amyloid metabolism is involved in APP and chromosomes 14 and 19 families, it suggests that Alzheimer's disease is a single disease with a common metabolic pathway. However, if other mechanisms are implicated, evidence is provided that Alzheimer's disease is a heterogeneous disorder that shares common clinicopathological features.

Alzheimer Disease↗
PubMed1994

Genetic analysis of a kindred with X-linked mental handicap and retinitis pigmentosa.

A kindred is described in which X-linked nonspecific mental handicap segregates together with retinitis pigmentosa. Carrier females are mentally normal but may show signs of the X-linked retinitis pigmentosa carrier state and become symptomatic in their later years. Analysis of polymorphic DNA markers at nine loci on the short arm of the X chromosome shows that no crossing-over occurs between the disease and Xp11 markers DXS255, TIMP, DXS426, MAOA, and DXS228. The 90% confidence limits show that the locus is in the Xp21-q21 region. Haplotype analysis is consistent with the causal gene being located proximal to the Xp21 loci DXS538 and 5'-dystrophin on the short arm of the X chromosome. The posterior probability of linkage to the RP2 region of the X chromosome short arm (Xp11.4-p11.23) is .727, suggesting the possibility of a contiguous-gene-deletion syndrome. No cytogenetic abnormality has been identified.

Adolescent↗
PubMed1994

Highly invasive papillary thyroid carcinoma.

Papillary carcinoma is the most common malignant tumour of the thyroid gland, accounting for at least two-thirds of newly diagnosed carcinomas. This tumour may be occasionally multicentric in origin. It frequently spreads to regional lymph nodes in the neck and mediastinum, but uncommonly metastasizes outside these regions. Local invasion of this tumour to the upper airway or digestive tract structures is infrequent. However, when that occurs, it is a source of significant morbidity and mortality. In the last two years four patients suffering from invasive papillary carcinoma to the aerodigestive tract were treated in our department. A short case history of one of them is presented and current trends in management of the disease are reviewed.

Carcinoma, Papillary↗
PubMed1994

Effectiveness of early therapy with corticosteroids in Stevens-Johnson syndrome: experience with 41 cases and a hypothesis regarding pathogenesis.

Evaluation of therapy for Stevens-Johnson syndrome was initiated as a retrospective analysis and then extended to a prospective series of patients treated with corticosteroids. This report extends the initial prospective study of patients with Stevens-Johnson syndrome treated with corticosteroids and evaluates the total series of 41 patients relative to outcome and the presumptive etiology. We propose that management of Stevens-Johnson syndrome requires corticosteroid therapy and that the survival of patients with Stevens-Johnson syndrome may depend on this therapy. No fatalities or adverse effects due to corticosteroids were noted. Stevens-Johnson syndrome due to a drug, a drug metabolite or viral infection may mimic a graft-versus-host reaction in which the patient rejects skin, mucous membrane, kidney or liver cells to which the drug, drug metabolite, or virus has bound. Corticosteroids suppress the inflammatory rejection until the activating agent has been eliminated.

Adolescent↗
PubMed1993

Clinical evaluation of M43: a novel cancer-associated mucin epitope.

A monoclonal antibody to colon carcinoma mucin was found to react with a colon carcinoma-associated carbohydrate epitope. This antibody was used to develop a quantitative solid phase immunoassay, M43. We prospectively and retrospectively evaluated the assay in patients with and without gastrointestinal carcinoma and compared the sensitivity and specificity with that of carcinoembryonic antigen (CEA) and CA 19-9. One hundred ninety-two patients (181 with no evidence of malignancy) referred for upper or lower gastrointestinal endoscopy were prospectively studied. Sera from 172 patients with histologically confirmed gastrointestinal adenocarcinoma were retrospectively studied. Optimal discrimination cutoffs for M43 (5 units/ml), CEA (5 ng/ml), and CA 19-9 (30 units/ml) were determined by receiver operating characteristic curves analysis. M43 was positive in 112 of 151 patients with colorectal carcinoma (sensitivity 74%) and was negative in 167 of 181 patients without carcinoma (specificity 92%). Sensitivity and specificity were 77% and 93% for CEA and 60% and 83% for CA 19-9. Sixty-four % of 73 patients with colorectal carcinoma limited to the bowel wall had a positive M43 with a mean value of 178 units/ml. Eighty-one % of 27 patients with nonhepatic metastasis had a positive M43 with a mean value of 223 units/ml. Eighty-four % of 51 patients with hepatic metastasis had a positive M43 assay with a mean value of 2532 units/ml. Sensitivity in these three groups was 67%, 82%, and 82%, respectively, for CEA and 43%, 68%, and 79%, respectively, for CA 19-9. Of 38 carcinoma patients with a negative CEA, 45% had a positive M43. No correlation between the levels of M43 and CEA in patients with colorectal carcinoma was found. We conclude that M43 is positive in most patients with colorectal carcinoma, even in early stages. As a diagnostic test, its sensitivity and specificity are equivalent to those of CEA. However, the M43 assay is measuring a tumor antigen which is fundamentally different from CEA and which is present in a high percentage of CEA-negative patients.

Adenocarcinoma↗
PubMed1993

Missed opportunities in preventive pediatric health care. Immunizations or well-child care visits?

OBJECTIVE: To determine the percentage of patients in a large pediatric practice in compliance with national recommendations regarding immunizations and well-child care visits. RESEARCH DESIGN: Chart review. Point estimates with 95% confidence intervals were determined for reviewed charts in compliance with recommendations of the Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention and schedule of well-child care visits, screening, and anticipatory guidance recommended by the American Academy of Pediatrics (AAP). SETTING: A large, multisite urban public pediatric practice. PATIENTS: Three hundred eighty-six infants and children (aged 0 to 60 months) who had a total of 7595 patient visits. SELECTION PROCEDURE: A random sample of charts. RESULTS: There was a large discrepancy in compliance for patients aged 0 to 23 months in ACIP-recommended immunizations (90.5% +/- 3.9%) vs AAP-recommended well-child care visits (37.6% +/- 6.4%) and for patients aged 24 to 60 months in ACIP-recommended immunizations (87.8% +/- 5.1%) vs AAP-recommended well-child care visits (31.0% +/- 7.1%). CONCLUSIONS: The data suggest that immunization alone does not ensure that children will receive all aspects of preventive care, raising questions about the practicality of the current AAP recommendations for preventive pediatric health care.

Child Health Services↗
PubMed1993

Quantification of the edge effect in calcified bioprosthetic tissues.

In bioprosthetic tissue samples that had been implanted in the subcutaneous space of rats, and recurring pattern of calcification was observed. In this pattern, which we call the edge effect, the interior of the tissue is calcified and is surrounded and separated from the subcutaneous fluid by a zone that is free from calcification. The edge effect has been qualitatively described in the literature for subcutaneous implants and for valve leaflets, and it may be related to the mechanism of calcification for these materials. The thickness of the calcification free outer layer was quantified for glutaraldehyde treated bovine pericardium, glycerol treated bovine pericardium, glutaraldehyde treated human dura mater, and glycerol treated human dura mater. The edge effect values were found to be unique and consistent for each material type, and they were inversely related to the shrinkage temperatures and the calcium contents of the materials. It was determined that the chemical treatment was more important than the tissue type in determining the edge effect value.

Abdomen↗
PubMed1993

Dichloroacetate inhibits peripheral efflux of pyruvate and alanine during hormonally simulated catabolic stress.

The purpose of this study was to examine the relationship of peripheral metabolism of glucose, lactate, alanine, and muscle protein catabolism to pyruvate availability during stress. Peripheral catabolic stress was simulated by the infusion of epinephrine, cortisol, and glucagon into the femoral artery of 12 healthy volunteers, 6 of whom received prior treatment with dichloroacetate while 6 served as controls. The catabolic hormone infusion reproduced the peripheral stress response in which glucose consumption increased and the efflux of lactate, alanine, and total amino acid nitrogen (i.e., net muscle protein catabolism) from the leg increased. Dichloroacetate (DCA), which is known to increase pyruvate oxidation, reduced the hormonally stimulated efflux of pyruvate and alanine from the leg and decreased the rate of extremity glucose consumption. DCA had no effect on the rate of lactate efflux and except for alanine had no effect on the stimulated rate of total amino acid nitrogen loss. These results demonstrate the dependence of alanine efflux on pyruvate availability during stress and suggest that the rate of glycolysis within peripheral tissues is a major factor in regulating the quantity of alanine efflux. This study further illustrates that except for alanine, pyruvate kinetics are not salient in the regulation of muscle protein catabolism and elucidates the dichotomy between alanine kinetics and true muscle protein breakdown.

Adult↗
PubMed1993

Left atrial thrombi in non-rheumatic atrial fibrillation: assessment of prevalence by transesophageal echocardiography.

To determine the prevalence of left atrial thrombus in hospitalized patients with non-rheumatic atrial fibrillation, 48 patients were consecutively studied with single-plane transesophageal echocardiography. There were 23 males (48%) and 25 females (52%). The mean age was 66 +/- 11 years (range 43-87). Thrombus was detected in 13 patients (27%): 11 were confined to the left atrial appendage, 1 to the atrial body and appendage, and 1 to the left upper pulmonary vein. Prevalence of atrial thrombus was not different among those patients with or without previous stroke [4/16 (25%) vs 9/32 (28%), p = NS] or between patients > 65 years and patients < or = 65 years old (p = NS). Atrial thrombus was detected more frequently in patients with reduced left ventricular global systolic function than in those with normal function [7/14 (50%) vs 6/34 (17%), p < 0.05]. In patients with spontaneous contrast echoes in the left atrium, thrombi were visualized more often than in those without spontaneous echoes [10/24 (41%) vs 3/24 (12%), p < 0.05]. The finding of the atrial spontaneous contrast echoes was more frequent among patients with reduced left ventricular global systolic function [11/14 (78%) vs 13/34 (37%), p < 0.02]. We conclude that in hospitalized patients with non-rheumatic atrial fibrillation the prevalence of left atrial thrombus is high. Reduced left ventricular global systolic function identifies a subset of patients at high risk for formation of thrombus in the left atrium.

Aged↗
PubMed1993

Genetic characterization of a familial non-specific dementia originating in Jutland, Denmark.

Dementias with non-specific pathological changes are a relatively common but under diagnosed form of presenile dementia. A high proportion of reported cases are familial. We report on molecular genetic findings in the largest known pedigree with this syndrome. We have excluded the mutations known to cause familial prion disease, APP-linked familial Alzheimer's disease and candidate regions for Huntington's disease, other forms of Alzheimer's disease and motor neuron disease. We have demonstrated that familial non-specific dementia is a novel genetic dementia.

Aged↗
PubMed1993

Preimplantation embryo sexing by polymerase chain reaction amplification of the sry gene on single mouse blastomeres.

Accurate and rapid sex determination of preimplantation embryos has great potential both in animal breeding and in human pathology. In the past, sex determination has been accomplished by cytogenetic or immunologic means and by polymerase chain reaction amplification of Y-chromosome-specific repetitive sequences. More recently, amplification of the Y-specific single-copy ZFY gene has been used in humans for sex determination of preimplantation embryos. The experiments reported here indicate that another Y-chromosome-specific single-copy gene, the sex-determining region gene (sry) can be successfully amplified from single mouse blastomeres. Blastocysts positive for sry amplification were reimplanted to foster mothers, and six of six newborns were male. We conclude that sry gene amplification can represent a good marker for embryo sex determination.

Animals↗