Search PubMed⌕ Search

Biomedical subjects

K Brown

Publications and source records attributed to K Brown.

At least 397 records · Page 22Linked to original sources
PubMed1989

Anatomy of the abdomen, back, and pelvis as displayed by magnetic resonance imaging: part three.

In April 1986, magnetic resonance imaging (MRI) of the thorax and shoulder girdle was presented at the 99th Annual Meeting of the American Association of Anatomists. These images were the authors' first attempt to correlate the magnetic resonance display of the muscles and soft tissues of the chest in the coronal plane with surface gross anatomy. The original purpose of this study was to introduce the role of magnetic resonance imaging to anatomists, medical students, and the specialty of radiology. However, this approach has been expanded by imaging other sections of the body and applying the display of surface anatomy to augment the teaching of anatomy to surgical oncology, pathology, and kinesiology. This three-part article will display magnetic resonance images and will explain how magnetic imaging of the soft tissues can visually augment the teaching of gross anatomy without dissecting surface tissues.

Abdomen↗
PubMed1988

The comparative recidivism rates of voluntary- and coerced-admission male alcoholics.

The outcomes of inpatient alcoholics who reported that they had been coerced into treatment by commitment or pressure from others were compared in a follow-up study to those of alcoholics who described themselves as voluntary admissions. Ten assessments of control over drinking, number of drinking days in the past week, and intoxication since previous appraisal were made by collaterals between 2 weeks and 18 months after treatment. Even though the data were analyzed in several ways, the number of significant differences did not exceed chance expectations. This suggests that the prognoses of alcoholics who present for treatment under court order or interpersonal pressure were not substantially different from those of men who claim to have entered without coercion. However, the differences between the groups' Control over Drinking ratings, even though not statistically significant, consistently favored the coerced admissions, which raises the possibility that their outcomes may have been slightly better than those of the voluntary admissions.

Adult↗
PubMed1988

Primary structure of c-kit: relationship with the CSF-1/PDGF receptor kinase family--oncogenic activation of v-kit involves deletion of extracellular domain and C terminus.

The protein kinase domains of v-kit, the oncogene of the acute transforming feline retrovirus HZ4-FeSV (HZ4-feline sarcoma virus), CSF-1R (macrophage colony stimulating factor receptor) and PDGFR (platelet derived growth factor receptor) display extensive homology. Because of the close structural relationship of v-kit, CSF-1R and PDGFR we predicted that c-kit would encode a protein kinase transmembrane receptor (Besmer et al., 1986a; Yarden et al., 1986). We have now determined the primary structure of murine c-kit from a DNA clone isolated from a brain cDNA library. The nucleotide sequence of the c-kit cDNA predicts a 975 amino acid protein product with a calculated mol. wt of 109.001 kd. It contains an N-terminal signal peptide, a transmembrane domain (residues 519-543) and in the C-terminal half the v-kit homologous sequences (residues 558-925). c-kit therefore contains the features which are characteristic of a transmembrane receptor kinase. Comparison of c-kit, CSF-1R and PDGFR revealed a unique structural relationship of these receptor kinases suggesting a common evolutionary origin. The outer cellular domain of c-kit was shown to be related to the immunoglobulin superfamily. The sites of expression of c-kit in normal tissue predict a function in the brain and in hematopoietic cells. N-terminal sequences which include the extracellular domain and the transmembrane domain as well as 50 amino acids from the C-terminus of c-kit are deleted in v-kit. These structural alterations are likely determinants of the oncogenic activation of v-kit.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1988

Isolation and characterization of the 5' flanking region of the mouse c-Harvey-ras gene.

The complete 5' flanking region of the murine c-Ha-ras gene was cloned and sequenced. An untranslated exon (-1) was identified and the promoter region of the gene located. Like the rat and human homologues, the murine promoter is GC rich and contains several GC boxes together with a CAAT element, but lacks a TATA box, an arrangement similar to that found in many housekeeping genes. From primer extension studies, the gene was shown to have three transcriptional start sites, whose positions differ from those previously found for the human gene. No alterations in these start sites were detected between the normal gene and activated Ha-ras genes from mouse skin tumors. A region of strong homology between mouse, rat, and human Ha-ras genes exists within the large intron separating exon (-1) from the first coding exon. In addition, from chloramphenicol acetyltransferase assays, the upstream region has promoter activity which appears to be enhanced by the inclusion of sequences within this intron.

Animals↗
PubMed1988

Histochemical, immunofluorescence, and ultrastructural differences in fetal cartilage among three genetically distinct chondrodystrophic mice.

The severe lethal chondrodystrophies in man result in a common clinical syndrome including shortening of the face, mandible, and limbs. Studies of three lethal chondrodystrophic mutants in mice, viz., chondrodysplasia (cho), cartilage matrix deficiency (cmd), and disproportionate micromelia (Dmm), which share this syndrome, were performed with the aim of identifying histochemical, immunofluorescence, or ultrastructural differences which might exist among these hereditary cartilage disorders. We examined limb cartilage epiphyses from day 18 normal and mutant fetuses and observed repeatable, mostly qualitative differences. All observations were made relative to the normal control. Histochemical staining of matrix proteoglycan was moderately decreased in cho and Dmm cartilage and markedly decreased in cmd when compared to the normal control. Staining of matrix collagen was irregular in distribution in cho, increased in cmd, and decreased in Dmm. Immunofluorescence of proteoglycan was increased in the matrix of cho and Dmm and decreased in cmd. Immunofluorescence of type II collagen was heterogeneous and moderately decreased in the matrix of cho, increased in cmd, and markedly decreased in Dmm. Immunofluorescence of link protein in cho was localized in the cellular-pericellular region as in the normal and appeared increased in the matrix of cmd and Dmm. Immunofluorescence of chondronectin was localized in the cellular-pericellular region and appeared normal in all three mutants. Major differences in cellular and matrix ultrastructure were observed among the mutants, including a decreased frequency of small-diameter collagen fibrils in cho and Dmm, increased density of collagen fibrils in cmd, and dilated RER in Dmm. These observations demonstrate that distinct structural and possibly molecular differences exist among the chondrodystrophies. In the case of cmd, the differences correlated with a previously reported molecular defect, viz., absence of core protein of cartilage specific proteoglycan in the cartilage of this mutant. It is anticipated that the methods used in the present study can be applied to humans in case classification and in identifying potential mouse-human correlates.

Animals↗
PubMed1988

A radioimmunoassay method for the determination of nedocromil sodium in plasma and urine.

A radioimmunoassay method for the determination of nedocromil sodium (FPL 59002 disodium salt) in human plasma and urine is described. The method employs a primary antiserum raised in a sheep, and a mono-tyramide derivative of nedocromil sodium labelled with iodine-125 as a heterogeneous radioligand. Free and bound radioligand are separated using a secondary anti-sheep IgG antiserum. All three reagents are added simultaneously to samples containing nedocromil sodium prior to an overnight incubation. The method has a limit of detection of 0.25 ng ml(-1), when plasma sample volumes of 100 microl are analysed, and is accurate and precise. Inter-assay relative standard deviations (N = 18) of 15.1, 5.0 and 5.6% were found at concentrations in plasma of 0.5, 2.0 and 6.0 ng ml(-1) respectively. The method is specific as indicated by negligible cross-reaction of the anti-nedocromil sodium antiserum with a range of drugs. The method is applicable to the analysis of samples from subjects who have inhaled nedocromil sodium from a pressurised aerosol.

Journal Article↗
PubMed1988

Diagnostic imaging techniques in mediastinal malignancies.

Mediastinal masses occur in both men and women of every age, and close to half of affected patients are asymptomatic. Screening of asymptomatic persons is not economically feasible. Symptomatic patients should be evaluated initially with posteroanterior and lateral chest radiographs. Additional imaging techniques may be required in patients suspected of having a mediastinal mass, when there is a questionable abnormality seen on chest radiographs or when local or systemic symptoms suggest a mediastinal mass. These techniques include oblique views, over-penetrated radiographs, and fluoroscopy of the chest. Computerized tomography of the chest is the imaging modality of choice for further assessment of a mediastinal mass. It can also be an important adjunct in radiotherapy portal planning. The use of other imaging modalities depends on the location of the tumor, the equipment available, and the expertise of local radiologists. In following up treated patients for disease recurrence, periodic chest radiographs are usually sufficient. Computerized tomography scans, because of their expense, should only be obtained as a baseline after completion of therapy or in patients with a suspected relapse.

Humans↗
PubMed1988

Knowledge and beliefs regarding the consequences of cigarette smoking and their relationships to smoking status in a biracial sample.

The purpose of this investigation was to evaluate carefully smoking-related knowledge and beliefs and their relationships to smoking status in a large, heterogeneous sample of smokers and nonsmokers in two settings: (a) a large, biracial southern city and (b) a small midwestern community. Participants were 611 (198 male, 413 female) adult respondents to a random-dialing telephone survey in Fargo, North Dakota (n = 200), and Memphis, Tennessee (n = 411). Each participant was given the Smoking Attitudes Survey, which assesses generalized health beliefs as well as health-related problems associated with smoking. Participants' knowledge of smoking-associated diseases (e.g., lung cancer) and of diseases not associated with smoking (e.g., kidney stones) was assessed. Stepwise regression analysis of composite knowledge scores revealed four independent predictors of the health consequences of smoking: education, race, smoking status, and income. Smokers, compared to nonsmokers, reported less knowledge related to the health consequences of smoking, were more likely to be male, were less concerned with the health consequences of smoking, and were more concerned about the health consequences of cholesterol. The best predictor of smokers who had never attempted cessation was their greater concern over weight control when compared to smokers with a history of smoking cessation attempts. The results are discussed in terms of smoking prevention and intervention efforts.

Black or African American↗
PubMed1988

Factors associated with participation, attrition, and outcome in a smoking cessation program at the workplace.

Despite their growing popularity, worksite health-promotion programs have generally been characterized as having low participation rates, high attrition rates, and modest outcomes. This investigation identified the predictors of participation, attrition, and outcome of worksite smoking-cessation program. Subjects were regular cigarette smokers recruited from two worksites. Of 66 eligible smokers in the two worksites, 44 (67%) agreed to participate in the program. Fifty-five percent (24 of 44) of these completed the program. Of those completing the program, 29% had quit smoking by posttest and 17% were abstinent at the 6-month follow-up. Results indicated that a different set of variables predicted participation, attrition, and outcome. The significant predictors of smokers who participated were the length of cessation in previous abstinence attempts, the number of years they smoked, and the belief regarding personal vulnerability in contracting a smoking-related disease. Levels of pretest carbon monoxide along with attitudes regarding the adoption of smoking restrictions in the worksite predicted attrition. Posttest cessation was related to nicotine levels of cigarette brand smoked at pretest and pretest beliefs regarding postcessation weight gain. Abstinence at the 6-month follow-up was predicted by the number of co-workers who smoked and pretest concerns related to postcessation weight gain. The results are discussed in terms of future evaluation and intervention efforts.

Adult↗
PubMed1988

c-kit protein, a transmembrane kinase: identification in tissues and characterization.

The proto-oncogene c-kit encodes a transmembrane kinase which is related to the receptors for colony-stimulating factor type 1 and platelet-derived growth factor, as well as to the immunoglobulin superfamily. Antibodies specific for the kinase domain of the P80 gag-kit protein of the Hardy-Zuckerman 4 feline sarcoma virus were prepared. These kit-specific antibodies were used to identify and characterize the c-kit protein in cat brain tissue. The c-kit protein product displays an autophosphorylating activity in immune complex kinase assays, and, in turn, this activity was used to identify the c-kit protein in different tissues. In cat brain, a single 145-kilodalton (kDa) glycoprotein was detected. Its N-linked carbohydrates were found to be sensitive to digestion with the endoglycosidases (neuraminidase, endoglycosidase F, and endoglycosidase H), indicating hybrid and/or complex and high-mannose structures. A partial purification of the c-kit protein was achieved by wheat germ agglutinin affinity chromatography, and the autophosphorylating activity of the partially purified c-kit protein was characterized and found to be specific for tyrosine. The kit antibodies cross-react with the murine c-kit protein product, and variant c-kit proteins in different mouse tissues were identified, with sizes of about 145 kDa (brain), 160 kDa (spleen), and 150 kDa (testis).

Animals↗
PubMed1988

Interrupter resistance elucidated by alveolar pressure measurement in open-chest normal dogs.

The interrupter method for measuring respiratory system resistance involves rapidly interrupting flow at the mouth while measuring the pressure just distal to the point of interruption. The pressure signal observed invariably exhibits two distinct phases. The first phase is a very rapid jump, designated delta Pinit, which occurs immediately on interruption of flow. The second phase is designated delta Pdif and is a further pressure change in the same direction as delta Pinit but evolving over several seconds. The physiological interpretations of delta Pinit and delta Pdif have been somewhat unclear. Delta Pinit has been taken to equal the pressure drop across the pulmonary airways, possibly with a contribution from the tissues of the respiratory system. Delta Pdif can arise, in principle, from two sources: gas redistribution throughout the lung after interruption of flow and stress recovery within the tissues. To resolve these issues we performed interruption experiments on anesthetized paralyzed, tracheotomized, open-chest normal dogs during passive expiration while measuring alveolar pressures at three sites with alveolar capsules. We found that, in the absence of the chest wall, delta Pinit reflects only the resistance of the airways and that delta Pdif can be ascribed almost entirely to the stress recovery properties of lung tissues.

Airway Resistance↗
PubMed1988

Evaluation of intrathoracic extent of lung cancer by plain chest radiography, computed tomography, and magnetic resonance imaging.

A comparison was made of the ability of plain chest radiography, computed tomography (CT), and magnetic resonance imaging (MRI) to detect and assess the intrathoracic extent of lung cancer in 46 patients. The chest radiographs (CXR) were obtained with a high kilovoltage phototimed technique. The CT scans were obtained with a GE 9800 machine and the MRI studies with a 0.3 Tesla permanent magnet imaging system. The primary tumor was well demonstrated by all 3 imaging techniques; however, the configuration of lesions was best demonstrated by CT. MRI was superior to CXR and CT for demonstrating hilar involvement in 4 cases. CT and MRI were generally comparable for demonstrating mediastinal involvement but were superior to CXR. In 2 cases, small normal size nodes seen on CT were considered to be a single large abnormal node on MRI. Because of the paucity of signal from flowing blood, compression and displacement of vessels were easier to identify with MRI. In 1 case, a small pleural effusion was better seen with CT than with CXR or with MRI. Direct chest wall involvement in 1 case was not seen by CXR. Vertebral body abnormality in another case was seen only by MRI and not by CXR or CT. At present, MRI, with its long scanning time, motion degradation of the image, and poor spatial resolution, is inferior to CT for imaging lung cancer. For evaluation of intrathoracic extent of lung cancer, CT remains the procedure of choice after performing plain chest radiography.

Adult↗
PubMed1988

Alcoholism in males with antisocial personality disorder.

Two hundred and sixty men entering an inpatient program for alcohol and drug treatment were interviewed and tested for cognitive disturbances and hepatic function. When the treatment group was separated by the presence or absence of antisocial personality disorder, the antisocial group was distinguished by several factors. Antisocial alcoholics were more likely to have an early onset of alcoholism and to be involved with other illicit drugs, and showed evidence of more problems with control of their drinking. They reported more alcohol-related problems as defined in DSM-III. Despite histories of a more severe form of alcoholism, the antisocials were no more likely to develop alcohol dependence or show signs of cognitive or hepatic toxicity.

Adult↗
PubMed1988

[Infection with equine herpesvirus and its manifestation in the central nervous system of the horse].

Infections with EHV1 can lead to manifestation at the CNS of horses followed by encephalomyelitis and "equine stroke". Horse experiments could confirm the clinical picture and gave links to the potential pathogenesis of the disease. We also have been in the position to isolate and characterize an EHV4 virus out of the brain of a horse with CNS disorders. The two viruses carry different biological properties which obviously dominate the pathogenesis. These properties as well as experimental and field cases are described and different diagnostic tests are discussed.

Animals↗
PubMed1988

Molecular analysis of chemical carcinogenesis in the skin.

The goal of understanding the molecular basis of human tumour development has been greatly facilitated by the use of animal model systems in which the aetiology of tumour development can be carefully controlled. Environmental chemicals, either naturally occurring or artificially produced, are thought to make a major contribution to the human tumour burden. The process of carcinogenesis can be divided operationally into the stages of initiation, promotion and progression and many different classes of chemical agents can act at one or more of these stages. Many of the concepts of multistage carcinogenesis have been developed and refined using the mouse skin model system and most of the work to be described in this article has been carried out in an attempt to analyse the molecular changes which are associated with the initiation of tumour development, the selection of initiated cells to form papillomas or the progression of premalignant tumours to carcinomas.

Animals↗
PubMed1988

Light and electron microscope localization of the microtubule-associated tau protein in rat brain.

We have studied the distribution of microtubule-associated tau proteins in rat brain using monoclonal and affinity-purified polyclonal antibodies. Tau staining is prominent in axons in white matter areas of brain, as reported by Binder et al. (1985). In addition, we also find tau protein in neuron cell bodies, especially in the brain stem and basal ganglia and in the cell bodies of interfascicular oligodendroglia. Using electron microscopy, tau antibodies and colloidal gold-labeled second antibodies, gold particles are found associated with microtubules in axons and in the cytoplasm of cell bodies, while the nuclei, mitochondria, and myelin remain unlabeled. In double-staining experiments, tau staining co-localizes with that of tubulin. Our studies indicate that tau proteins are more widely distributed in brain than previously reported and cannot be used as an exclusive marker for axons.

Animals↗