Search PubMed⌕ Search

Biomedical subjects

C Lee

Publications and source records attributed to C Lee.

At least 919 records · Page 51Linked to original sources
PubMed1985

Proteins of the rat prostate: I. Preliminary characterization by two-dimensional electrophoresis.

The rat prostate consists of three distinct lobes: the ventral, lateral, and dorsal. Proteins in the three lobes of the prostate were studied with the ISO-DALT system for high-resolution two-dimensional electrophoresis. Proteins were detected with ammoniacal silver stain. Comparison of patterns from the three lobes of the prostate of control, noncastrated rats revealed that while there was a remarkable overall similarity, six groups of proteins showed lobe-specific differences. When prostatic regression was induced by castration, androgen-dependent proteins showed a decrease in staining intensity. A group of proteins, with pI 5.0-6.0 and MW 65,000-70,000, was consistently observed only during the active phase of prostatic regression (days 3-7 postcastration). Their presence during this specific interval may play a role in tissue involution.

Animals↗
PubMed1985

Abnormal embryonic development induced by antibodies to rat visceral yolk-sac endoderm: isolation of the antigen and localization to microvillar membrane.

An antigenic substance was isolated from rat visceral yolk-sac endoderm of the 18th-20th days of gestation by extraction with the nonionic detergent Nonidet P-40, Sephacryl S-300 gel filtration, and Ricinus communis agglutinin affinity chromatography. The rabbit antiserum directed against this antigenic substance when injected into pregnant rats during the period of organogenesis caused abnormal embryonic development, fetal growth retardation, and embryonic death. Ouchterlony gel diffusion analysis demonstrated that the antiserum formed one immunoprecipitin band against the crude detergent extract and a complete identity between the present visceral yolk-sac antigen and the renal glycoprotein antigen previously isolated (C. C. K. Leung, (1982) J. Exp. Med. 156, 372-384). The antigen eluted from the antibody affinity column appeared to consist of two major peptides of 60 and 30 kDa when analyzed by SDS-polyacrylamide gel electrophoresis. Indirect immunofluorescent and immunoperoxidase localization studies at the light microscopic level demonstrated that both rat renal proximal tubule and embryonic visceral yolk-sac endoderm at various gestational stages (including the organogenetic period) shared the same antigen. Indirect immunoperoxidase localization studies at the electron microscopic level demonstrated that the antigen was a part of (or associated with) the microvillar membrane and membrane invaginations at the base of the microvilli of the renal proximal tubule and visceral yolk-sac endoderm. In vivo immunoperoxidase localization studies demonstrated that the teratogenic antibodies localized within the large phagolysosomes and the apical vesicles of the visceral yolk-sac endoderm. It is postulated that visceral yolk-sac pathology was induced by the antibodies.

Animals↗
PubMed1985

The effect of testicular irradiation on established BPH in the dog: evidence of a non-steroidal testicular factor for BPH maintenance.

Irradiation of the testes of four to 13-year-old male beagles with benign prostatic hyperplasia (BPH) was undertaken to attempt to evaluate the possibility that the testes secrete a non-androgenic accessory sex gland-stimulating substance that may have a critical role in the development of BPH. Available evidence indicates that development of prostatic hyperplasia in dog and man is dependent on testicular secretions and that testes irradiation is unlikely to alter testosterone secretion appreciably but does produce profound effects on the seminiferous tubules. Thirteen non-irradiated and shoulder irradiated control and 16 beagles subjected to 1500 to 2200 rads single dose testis irradiation had pre-irradiation, interval post-irradiation and terminal caliper measurements of prostatic length, width and depth, prostatic and testicular biopsies, and determination of serum testosterone and estradiol levels. Four beagles survived in a group observed for 109 weeks post testis irradiation, 12 in a group observed for 51 and 10 in a group observed for 59 weeks. The wet weight of the prostate was determined at sacrifice. Ratios of the final/initial length and width and final actual/initial calculated weight of the prostate were significantly decreased in testis-irradiated as compared to control beagles. Histologic evaluation also demonstrated a significant difference in degree of prostatic stimulation in control and testis-irradiated groups. The serum testosterone and estradiol levels were not significantly different in the testis-irradiated and control beagles. These observations indicate that irradiation of the testes of beagles with BPH alters the size, weight and histology to suggest decreased stimulation of the prostate without producing an identifiable change in the serum levels of the steroid hormones studied. The data support the hypothesis that the testis of the aging beagle secretes a non-androgenic and probably non-steroidal prostatic stimulating substance which is affected by irradiation of the testis.

Animals↗
PubMed1985

Estimation of canine prostatic size by in vivo ultrasound and volumetric measurement.

Two methods for estimating the weight of the canine prostate gland in vivo were investigated. Twenty-six beagle dogs underwent transrectal and transabdominal ultrasound examination of the prostate, followed by careful, standardized caliper measurement of the prostate at surgical exploration. The prostate glands were then removed and weighed, and nomograms were constructed for use in future laboratory research. The validity of these nomograms for determining prostate weight in vivo was confirmed on evaluation of 6 additional dogs.

Animals↗
PubMed1985

Purification and some properties of rabbit liver cytosol thioltransferase.

Thioltransferase was purified 650-fold from rabbit liver by procedures including acid treatment, heat treatment, gel filtration on Sephadex G-50, column chromatography on DEAE-cellulose, isoelectric focusing (pH 3.5-10) and gel filtration on Sephadex G-75. The final enzyme preparation was almost homogeneous in polyacrylamide gel electrophoretic analysis. Only one active peak with an apparent molecular weight (Mr) of 13,000 was detected by gel filtration on Sephadex G-50 and only a single protein band with a molecular weight of 12,400 was detected by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. Isoelectric focusing revealed only one enzyme species, having an isoelectric point (pI) of 5.3. The enzyme has an optimum pH about 3.0 with S-sulfocysteine and GSH as substrates. The purified enzyme utilized some disulfides including S-sulfocysteine, alpha-chymotrypsin, trypsin, bovine serum albumin, and insulin as substrates in the presence of GSH. The enzyme does not act as a protein : disulfide isomerase (the activity of which can be measured in terms of reactivation of randomly reoxidized soybean Kunitz trypsin inhibitor). The enzyme activity was inhibited by chloramphenicol, but not by bacitracin. The inhibition by chloramphenicol was non-competitive (apparent K1 of 0.5 mM). Thioltransferase activity was found in the cytosol of various rabbit tissues.

Animals↗
PubMed1985

An immunoblot study of neurofilament degradation in situ and during calcium-activated proteolysis.

The degradation of neurofilament (NF) proteins was examined by immunoblot methods to identify, characterize, and monitor the appearance of immunoreactive breakdown products during the loss of NF triplet proteins. Individual NF proteins and their breakdown products were identified using polyclonal and monoclonal antibodies to NF proteins. NF degradation was compared during calcium-activated proteolysis of isolated rat NF, during an experimental influx of calcium into excised rat spinal nerve roots, and during NF breakdown in transected rat peripheral nerve. These different experimental conditions produced similar patterns of NF fragmentation, including the transient appearance of NF immunobands between Mr 150,000-200,000 and 110,000-120,000 as well as the appearance and accumulation of NF immunobands between Mr 45,000 and 65,000. Most immunoreactive NF fragments remained Triton-insoluble. Low levels of the same immunoreactive fragments were present in control neural tissues, suggesting that calcium-activated proteolysis may be operative in the turnover and/or processing of NF proteins in vivo. Very similar patterns of NF degradation during experimental calcium influxes into different CNS and PNS tissues are indicative of the widespread distribution of calcium-activated NF protease in neural tissues.

Animals↗
PubMed1985

Imaging the centenarian brain. A computed tomographic study.

Ten healthy and mentally alert centenarians underwent cranial computed tomography (CT) using a fourth-generation CT scanner. The subjects ranged in age from 100 to 102 years, and included six women and four men. Two of them used alcohol on a daily basis and five had systolic blood pressures of at least 160 mmHg. The CT scans demonstrated considerable variation in the degree of cerebral atrophy, which had no relation to either sex, alcohol use, or hypertension. Three of the centenarians had evidence of mild periventricular white matter lucency. Although progressive cerebral atrophy is an integral aspect of the normal aging process in the very elderly, its exact relationship to cognitive function remains unclear.

Aged↗
PubMed1985

Brain biopsy in cases of neonatal herpes simplex encephalitis.

Neonatal herpes simplex encephalitis (HSE) can represent a difficult diagnostic problem when it occurs without concomitant mucocutaneus lesions and usually requires brain biopsy for diagnosis. Asymptomatic for the initial 2 to 4 weeks of life, the three infants we describe with localized HSE came to medical attention only because they developed persistent seizures and other nonspecific symptoms. Lumbar spinal fluid obtained from these children at clinical presentation showed an encephalitic pattern. Radionuclide brain scans revealed focal uptake of isotope in a variety of cortical areas, and electroencephalograms (EEGs) demonstrated repetitive, high amplitude, polyphasic sharp waves arising from analogous regions. Computed tomography (CT) showed nonspecific ill-defined areas of low density or contrast enhancement that did not correlate well with radionuclide, EEG, or clinical findings in two neonates. No infant had predominant temporal lobe involvement. Because these data suggested a multifocal, encephalitic process, all three infants underwent brain biopsy. A widespread infiltration of leukocytes and macrophages was observed in each specimen, and abundant intranuclear inclusions were present. Electron microscopy revealed abundant herpesvirus particles, and herpes simplex virus (HSV) was subsequently isolated from each sample. From our observations and our review of the literature, we propose the following criteria as indications for brain biopsy: Brain biopsy is warranted to rule out HSE when a neonate presents with seizures, cerebrospinal fluid mononuclear pleocytosis with a negative gram stain, and focal, cortical disease on EEG and radionuclide scan.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗
PubMed1985

Increasing performance appraisal effectiveness: matching task types, appraisal process, and rater training.

The search for one best performance appraisal format ignores differences among jobs. A performance appraisal system tailored to fit ratee task characteristics is proposed. This approach, which involves systems designed to deal with tasks where both availability of reliable and valid performance measures and knowledge of the transformation process may be either high or low, is expected to increase the relationship between observational accuracy and accuracy in rating performance, as well as to improve ratees' future performance.

Employee Performance Appraisal↗
PubMed1985

Two-dimensional electrophoretic analysis of human prostatic fluid proteins.

The heterogeneous mixture of proteins present in expressed prostatic fluid from forty-nine men over 25 years old was analyzed on two-dimensional electrophoretic gels stained with silver. Samples were collected from men diagnosed with chronic prostatitis, urinary tract infection, benign prostatic hypertrophy (BPH), and prostatic carcinoma. Reference patterns were developed for all proteins observed in electrophoretograms. Over 1000 distinct proteins are contained in the comprehensive proteins pattern of prostatic fluid; however, only 18 proteins were common to all samples. No proteins unique to fluids from men with BPH or prostatic cancer were observed. Some proteins in the common proteins reference pattern of BPH patients were not seen in samples from men with prostatic cancer. Our preliminary results indicate that a series of proteins tentatively identified as variants of prostatic acid phosphatase appeared elevated in all BPH fluids but was absent or below limits of detection in samples from men with prostatic carcinoma. Our studies indicate that proteins secreted in prostatic fluid reflect physiological changes in the prostate, and certain changes may be useful indicators of malignant transformation.

Adult↗
PubMed1985

Comparison of intravenous administration with intrauterine irrigation with ceforanide for nonelective cesarean section.

A randomized, prospective, double-blind study was designed to compare intravenous administration with intrauterine irrigation using an extended half-life (t1/2 = three hours) cephalosporin, ceforanide. Patients included in the study had a nonelective cesarean section with rupture of membranes for three hours or longer. Sixty-four patients received a single dose of ceforanide immediately after clamping the umbilical cord. Patients were similar in both groups in age, weight, length of labor, and duration of ruptured membranes. The group receiving the intravenous ceforanide had a significantly shorter duration of surgery than the patients receiving the intrauterine ceforanide. Endometritis infection rates were similar, 11.8% (intravenous) versus 11.1% (intrauterine), P greater than .1. Serum levels were as much as tenfold higher in the intravenous group versus the intrauterine group. Intrauterine irrigation with an antimicrobial agent provided no advantage over systemic administration.

Adult↗
PubMed1985

Collagen biosynthesis in human neuroblastoma cell lines: evidence for expression of glial cell properties.

An analysis was done on the synthesis of collagen, an extracellular matrix protein synthesized by Schwann cells, by several human neuroblastoma lines. Cultured cells were incubated in the presence of L-[2,3-3H]proline, and the collagens synthesized and secreted into the culture medium were analyzed by electrophoresis on acrylamide gels, ion exchange chromatography, and immunoprecipitation. The amount of collagen secreted by 4 cell lines tested represented less than 3% of the total protein synthesis, indicating a low degree of collagen biosynthesis by this tumor type. Analysis of collagen types secreted by all cell lines revealed the presence of a high-molecular-weight collagen precursor (Mr = 165,000) identified as type IV procollagen. In addition, several cell lines synthesized stromal type I and type III collagens. These studies show that neuroblastoma cells produce collagenous proteins including basement membrane collagen (type IV) and stromal collagens (types I and III), indicating that these cells express properties of glial cells such as Schwann cells.

Animals↗
PubMed1985

Effects of verapamil on uterine blood flow and maternal cardiovascular function in the awake pregnant ewe.

Calcium entry blocking drugs may have a role in the treatment of maternal and fetal tachyarrhythmias, as well as for treatment of premature labor. This study was undertaken to assess the hemodynamic effects of verapamil in the awake pregnant ewe. Verapamil, 0.2 mg/kg administered intravenously over 3 min, resulted in the following maternal cardiovascular changes: transient (2 min) but significant decreases in systolic, diastolic, and mean blood pressures, and significant but equally transient increases in central venous pressure and mean pulmonary arterial pressure. Pulmonary capillary wedge pressure increased for 5 min. These results are consistent with the negative inotropic and peripheral vasodilating effects of verapamil. Cardiac output, systemic vascular resistance, and pulmonary vascular resistance were unaffected. Uterine blood flow decreased 25% at 2 min and remained significantly (7-18%) below control levels for 30 min after drug injection. The effects of verapamil on uterine blood flow suggest that it should be used with caution in cases where uteroplacental perfusion is compromised.

Animals↗