Search PubMed⌕ Search

Biomedical subjects

C Chow

Publications and source records attributed to C Chow.

72 records · Page 4Linked to original sources
PubMed1990

Breakdown approach helps managers select projects.

In an era of increased financial strain, effective capital budgeting is critical to a hospital's continued viability. Without accurate estimates of a project's costs and benefits, however, even the most sophisticated selection method is subject to a capital manager's prediction errors. Rather than use typical performance reports to evaluate particular projects or the managers proposing them, administrators should scrutinize the assumptions behind managers' predictions. A decomposition or divide-and-conquer approach can assist in this analysis.

Budgets↗
PubMed1989

Biochemical evidence for enhanced sensitivity to N-methyl-D-aspartate in the hippocampal formation of kindled rats.

The inhibitory effect of N-methyl-D-aspartate (NMDA) upon carbachol-stimulated phosphoinositide (PI) hydrolysis was studied in transverse hippocampal slices prepared from control and amygdaloid kindled rats. Kindling significantly increased the inhibitory effect of NMDA (10 microM) in slices prepared from animals 24 h after the last class 5 kindled seizure, resulting in a steepening of the dose-response curve for NMDA. The enhanced sensitivity to NMDA was long-lasting in that it was also present in slices prepared from animals sacrificed 28-35 days after the last class 5 seizure. The increased sensitivity to NMDA was selective in that inhibition of carbachol-stimulated PI hydrolysis by kainic acid or phorbol-12,13-diacetate was not different in control and kindled animals. Neither NMDA, kainic acid, phorbol ester nor carbachol alone had any significantly different effects in slices from kindled versus control animals. These data demonstrate a selective and enhanced sensitivity of the kindled hippocampus to NMDA. This enhanced sensitivity to the principal class of excitatory neurotransmitter may be one mechanism underlying the development and maintenance of kindled epilepsy.

Animals↗
PubMed1988

Immunocytochemical and electrophoretic analyses of changes in myosin gene expression in cat posterior temporalis muscle during postnatal development.

Changes in myosin gene expression during the postnatal development of the homogeneously superfast kitten posterior temporalis muscle were examined using immunocytochemical techniques supplemented by pyrophosphate gel electrophoresis and gel electrophoresis-derived enzyme linked immunosorbent assay (GEDELISA) of myosin isoforms. The antibodies used were polyclonals directed against the heavy chains of superfast and foetal myosins and monoclonals against the heavy chains of slow and fast myosins. The fibres of the posterior temporalis in the newborn kitten stained almost uniformly with the anti-foetal myosin antibody and the largest of these fibres stained strongly for superfast myosin. A subpopulation of fibres staining for superfast myosin also stained lightly for slow myosin. These slow staining fibres were evenly distributed in the centres of muscle fibre bundles, reminiscent of primary fibres in limb fast muscle. During subsequent development, slow myosin staining disappeared and superfast myosin replaced foetal myosin so that by 50 days the muscle was virtually homogeneously superfast as in the adult. Fast myosin was never expressed at any stage. It is proposed that fibres staining transiently for slow myosin are superfast primary fibres which are homologous to fast primary fibres recently described in regions of limb muscles devoid of slow fibres in the matured animal. Other jaw-closing muscles have significant populations of slow fibres in the mature animal and it is postulated that there exists in these muscles a second class of jaw primary fibres, the slow primary fibres, in which slow myosin synthesis would be sustained in the adult. It is suggested that the myogenic cells of jaw-closing and limb muscles are of two distinct types preprogrammed to express different muscle genes.

Animals↗
PubMed1987

Fish oil increases peripheral capillary blood cell velocity in humans.

Fish oils containing n-3 fatty acids have been shown in humans to decrease platelet aggregation in vitro, lower plasma triglycerides, and to increase bleeding time. The in vivo effects of fish oils on microcirculatory blood flow in humans has not been studied to date. Twenty-one male subjects were randomly assigned to either olive oil (n = 10) or fish oil (n = 11) supplemented groups to determine the effects of these oils on capillary blood flow velocity (CBV) in the nailfold area. The subjects were given the oils for three weeks (1.5 g oil/10 kg b.wt./day) in a single blind study design. In addition to CBV plasma lipid profiles, blood viscosity, blood pressure and platelet and erythrocyte fatty acids were also determined prior to and after the dietary intervention. Fish oil supplementation significantly increased CBV, by 1.75-fold (0.144 +/- 0.069 to 0.253 +/- 0.147 mm/s). The olive oil group remained unchanged. Increased levels of n-3 fatty acids were noted in platelets and erythrocytes of the fish compared to olive oil-supplemented groups. Blood viscosity was unaltered in both groups, however, blood pressure in the olive oil supplemented group was significantly decreased. Plasma triglycerides were significantly decreased in the fish oil supplemented group. These observations suggest that increases in CBV after fish oil supplementation are due to changes in vascular tone and not to alterations in blood pressure or blood viscosity.

Adult↗
PubMed1987

Interaction of high density lipoprotein with adipocytes in a new patient with Tangier disease.

A 56-year-old man, the offspring of a consanguineous first cousin marriage, presented with clinical, morphological, and biochemical features of familial deficiency of high-density lipoproteins (Tangier disease). Of 8 first- and second-degree relatives examined, 4 had either plasma apo A-I or HDL cholesterol concentrations 2 standard deviations below normal population mean on at least 1 occasion. The patient and a majority of his relatives also had high plasma apo B concentrations relative to their levels of cholesterol. Adipose tissue biopsy was undertaken to study HDL interaction with the patients' cells. Specific uptake of HDL3 was demonstrated in adipocytes of this patient, but was decreased relative to a control of similar fat cell size. However, no marked difference in fat cell cholesterol content was observed between the Tangier patient and the control. Thus it appears unlikely that adipocytes play a role in the etiology of Tangier disease.

Adipose Tissue↗
PubMed1986

Application of a new spatial signal averaging device for the beat-to-beat detection of cardiac late potentials.

A new high resolution digital signal averaging device was developed to record precordial late potentials. The subjects examined included 8 normals (including medical patients with normal cardiovascular status), and 21 patients with coronary artery disease (CAD) and myocarditis of probable viral origin. Late potentials were evident in 11 cases (CAD 8 cases and myocarditis in 3 cases). In 10 patients, multiple ventricular premature beats and in 3 others, attacks of ventricular tachycardia had been present. Sudden cardiac death occurred later in one patient. It was concluded that late potentials as recorded by this simple new device are predictive of ventricular arrhythmias--sometimes life threatening. As no triggering is necessary, both conventional and beat-to-beat signal averaging can be carried out and the presence of various arrhythmias is negligible.

Adult↗
PubMed1978

Percutaneous absorption of hexachlorophene in rats, guinea pigs and pigs.

A comparative study of the percutaneous absorption of hexachlorophene (HCP) was undertaken in rats, guinea pigs and pigs. [14C]Hexachlorophene ([14C]HCP) was applied evenly over the shaved back of the animals at a dose of 40 microgram/cm2 skin surface. Urine and feces were collected at 24-h intervals for 5 days from animals kept in metabolism cages. Different methods were used for quantitating the percutaneous absorption of HCP. This study showed that skin permeability to HCP decreased in the following order: rat, guinea pig and pig. The permeability characteristics of the pig skin to topically applied HCP were comparable to the published human data. We suggest that pig may be a suitable animal model for studying the percutaneous absorption of antimicrobial drugs.

Animals↗
PubMed1975

Laboratory diagnosis of Bence Jones proteinuria in a patient with plasma cell leukemia.

Kappa Bence Jones proteinuria was found by immunoelectrophoretic techniques in a patient with plasma cell leukemia, who presented with no M-proteins either in serum or urine. However, a significant decrease in normal immunoglobulins was observed. On microscopic examination of kidney sections obtained a autopsy, protein casts were seen in the distal tubules. Bence Jones protein was not detected by the conventional heat test.

Bence Jones Protein↗
PubMed1972

Halobacterium cutirubrum ribosomes. Properties of the ribosomal proteins and ribonucleic acid.

1. The 30S ribosomal subunit of the extreme halophile Halobacterium cutirubrum is unstable and loses 75% of its ribosomal protein when the 70S ribosome is dissociated into the two subunits. A stable 30S subunit is obtained if the dissociation of the 70S particle is carried out in the presence of the soluble fraction. 2. A fractionation procedure was developed for the selective removal of groups of proteins from the 30S and 50S subunits. When the ribosomes, which are stable in 4m-K(+) and 0.1m-Mg(2+), were extracted with low-ionic-strength buffer 75-80% of the 30S proteins and 60-65% of the 50S proteins as well as the 5S rRNA were released. The proteins in this fraction are the most acidic of the H. cutirubrum ribosomal proteins. Further extraction with Li(+)-EDTA releases additional protein, leaving a core particle containing either 16S rRNA or 23S rRNA and about 5% of the total ribosomal protein. The amino acid composition, mobility on polyacrylamide gels at pH4.5 and 8.7, and the molecular-weight distribution of the various protein fractions were determined. 3. The s values of the rRNA are 5S, 16S and 23S. The C+G contents of the 16S and 23S rRNA were 56.1 and 58.8% respectively and these are higher than C+G contents of the corresponding Escherichia coli rRNA (53.8 and 54.1%).

Amino Acids↗
PubMedDate not supplied

Metastatic melanoma: correlation of MRI characteristics and histopathology.

To correlate the findings on MRI with histopathology of metastatic melanoma, MRI was performed on 29 patients with 36 lesions, using spin-echo and inversion recovery sequences. Histopathologic examination of lesions was performed within 4 weeks of imaging. Lesions were categorized according to cell type and were also evaluated for the presence and extent of melanin, iron, and necrosis. These data were then correlated with the signal intensities of the lesions. Enhancement of lesions after injection of intravenous gadolinium was calculated and correlated to vascularity of the tumor. Melanin was present more frequently in lesions appearing hyperintense or with mixed signal intensity (12/15) than in those appearing hypo- or isointense (6/21) on the T1-weighted sequence. This trend was significant (P = .013). Also, more lesions appearing mixed, ie, having both hypo- and hyperintense components, contained melanin (15/23), as opposed to lesions that appeared to be only hyperintense (3/13) on the STIR sequence. There was no clear association between signal intensity and melanin content on the T2-weighted sequence. There was no significant association between the signal intensities on the MR images and the iron content, tumor size, or tumor cell type of these lesions. There was no clear association between enhancement after gadolinium injection and vascularity, as assessed by histology. The authors concluded in this study that T1 shortening and hypointensity on the STIR sequence seen in patients with metastatic melanoma are most closely related to the melanin content of the tumor.

Adult↗
PubMedDate not supplied

Localized bumps of activity sustained by inhibition in a two-layer thalamic network.

Based on head direction experiments in rats, the existence of localized bumps of thalamic activity has been proposed. We computationally demonstrate the existence of a novel class of localized bump solutions in a two-layer conductance-based thalamic network and analyze the mechanisms behind these stable patterns. In contrast to previous models of bump activity, here inhibition plays a crucial role in initially spreading neuronal firing and in subsequently sustaining it. In our model, we incorporate local strong, fast GABA(A) inhibition and diffuse weak, slow GABA(B) inhibition, based on previous biophysical experiments. These forms of inhibition contribute in different, yet complementary, ways to the observed pattern formation.

Animals↗
PubMedDate not supplied

Detection of cervical neoplasia using measurement of Brn-3a in cervical smears with persistent minor abnormality.

Measurement of the Brn-3a cellular transcription factor in cervical smears from women referred for colposcopy may improve the detection of underlying cervical neoplasia. In those women referred with persisting borderline or mildly dyskaryotic smears, those who had histologically proven underlying CIN II/III, had statistically significant higher Brn-3a levels than those with a similar smear but histologically shown to have HPV, CIN I, or no cervical abnormality. These results indicate that Brn-3a could play an important role in the near future in improving cervical cancer screening.

Adult↗
PubMedDate not supplied

Urinary lactate dehydrogenase isoenzyme analysis in adult population.

This investigation was a systemic study on an adult population of urinary lactate dehydrogenase (LDH) isoenzyme analysis for the distinction between upper and lower urinary tract infections. The study included 160 urine samples from patients and healthy individuals. On the basis of clinical symptoms, urinary bacterial colony counts, renal function tests and radiologic findings, the adults were divided into pyelonephritis group, cystitis group, pelvic lesion group, and control group. This technique correctly identified 23 of 26 patients with pyelonephritis by the presence of elevated LDH-V (over 10 percent) and all of 12 patients with cystitis by the presence of elevated LDH-I (over 60 relative units) but low LDH-V (below 10 percent or lower than LDH-I). In the pelvic group, the results of eight patients were consistent with cystitis and four with pyelonephritis. Our study confirms the sensitivity and specificity of the LDH isoenzyme technique for the differential diagnosis of urinary tract infection on adult patients and is consistent with previous studies on pediatric patients. However, one should be cautious to interpret the results of LDH isoenzymogram before extra-urinary tract lesions are excluded.

Adolescent↗
PubMedDate not supplied

Management of arthritis.

Explore the source record for details and available documents.

Adrenal Cortex Hormones↗