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Biomedical subjects

K C Wang

Publications and source records attributed to K C Wang.

At least 127 records · Page 7Linked to original sources
PubMed1991

Femoral neck fractures. 121 cases treated by Knowles pinning.

The femoral neck fracture remains one of the unsolved fractures. It is a fracture with a high incidence of nonunion and avascular necrosis. One hundred twenty-one mostly young adult patients with femoral neck fractures were treated by Knowles pins internal fixation. Patients were observed for an average of 32 months following surgery. Union occurred in all Garden Stage I and II undisplaced fractures, and the incidence of nonunion was 14% in Garden Stage III and IV displaced fractures. The incidence of avascular necrosis was 5.9% in undisplaced fractures and 34.5% in displaced fractures. There was no significant difference in avascular necrosis rates among age groups. Nonunion and avascular necrosis occurred mainly in displaced fractures. Knowles pinning offers the advantages of few technical failures, early weight bearing, high union rate, and low complication rate.

Adolescent↗
PubMed1991

Application of modern NMR techniques in the structure determination of microbial transformation products from sterols.

Microbial transformations of cycloartenol, 24-methylenecycloartanol and lanosterol with Mycobacterium sp. (NRRL B-3805) resulted in the isolation and characterization of five C19 steroids. Details of the tremendous structural modifications of these metabolites from their parent compounds were clarified by 2D nmr techniques. The stereochemistry of these novel metabolites was determined by nOe studies.

Lanosterol↗
PubMed1990

Deep sylvian meningioma in a child.

Meningioma is a rare brain tumor in childhood, but one located deep in the sylvian fissure without any connection to the dura or ventricular system is even more unusual. A 2-year-old boy with a deep sylvian meningioma is presented. This is the youngest case as well as the third intrasylvian meningioma reported in the pediatric age group (up to age 15).

Child, Preschool↗
PubMed1990

The fate of spargana inoculated into the cat brain and sequential changes of anti-sparganum IgG antibody levels in the cerebrospinal fluid.

To establish an animal model of intracranial sparganosis, the fate and behavior of the experimentally inoculated spargana were observed. A total of 102 scolices of spargana were injected into 22 cat brains, and the cats were sacrificed at 2 weeks, 1 month, 3 months and 6 months after the inoculation. Neurosparganosis was established in 77% of the cats. Of 43 recovered worms, 19 (44%) were located in the subdural or subarachnoid space, 16 (37%) in the brain parenchyme, and 2 (5%) in the lateral ventricle. One was detected at the diploic space of the skull and 5 were outside the cranial cavity. All but one were alive, and had grown tails. They were distributed in the brain parenchyme randomly. There was no place which they could not invade. No adult was found in the intestine. Cerebrospinal fluid (CSF) was collected before inoculation, 1 week, 2 weeks, 1 month, 3 months and 6 months after inoculation. The level of anti-sparganum IgG antibody in CSF measured by ELISA began to increase above the criteria of positivity 1 month after inoculation. Three months after inoculation, the values markedly increased. The present findings reveal that intracranial inoculation of spargana into the brains of cats would be a good animal model of experimental neurosparganosis.

Animals↗
PubMed1990

Suppression of hemodynamic change before extubation--lidocaine through modified endotracheal tube.

Twenty females, aged 31 to 49 years, scheduled for abdominal total hysterectomy were randomly divided into two groups in this study. An epidural catheter was placed at T11-12 before general anesthesia. All patients receive the combination of epidural anesthesia and general anesthesia for the operation and relief of pain postoperatively. The modified endotracheal tube we used is shown in Fig. 1. For patients in group I (Lidocaine group), 2 mL 4% lidocaine solution was injected through the catheter to desensitize the tracheal mucosa around the cuff after the surgeon had removed the uterus. In group II (Control group), no special management was made. All patients were not extubated until they were considered to be awake. Systolic blood pressure at three and one minute before extubation and pulse rate recorded at one minute before extubation showed in patients of group I were statistically smoother than those recorded in group II (p less than 0.01). All patients had gag reflex just after awake extubation.

Adult↗
PubMed1990

A new approach to suppress bucking before extubation--lidocaine through modified endotracheal tube.

The conventional endotracheal tube was modified with an epidural catheter adhered on the concave aspect of it. The opening of the catheter is at the proximal margin of the cuff. Local anesthetic can be injected into the trachea, then desensitize the tracheal mucosa nearby the cuff. Thirty-four female gynecological patients underwent abdominal total hysterectomy were studied and divided into three groups. In group 1, anesthesia was maintained without special management. In groups 2 and 3, 2 mL gentian violet stained 4% lidocaine solution was administered intratracheally by two different methods 60-120 minutes before the conclusion of the surgery. The peak cuff pressures generated by the awakening patients were 53.8 +/- 2.2 cm H2O (mean +/- SE) in group 1, 47.3 +/- 2.5 cmH2O (Group 2) and 36.4 +/- 1.6 cmH2O Group 3) respectively. Bucking before awakening was also evaluated clinically and showed 100%, 73% and 0% in each group. Intratracheal administration of lidocaine in dose of 2 mL 4% showed significant effect for the suppression of bucking during the recovery of general anesthesia in group 2 and 3 compared with the group 1. Lidocaine administered through the catheter of modified endotracheal tube also resulted in less increase in the peak cuff pressure and even no clinically observed bucking than direct administered through the endotracheal tube. Gag reflex was preserved in all patients and none had suffered from aspiration postoperatively.

Adult↗
PubMed1989

Ultrastructural studies of the cells forming amyloid fibers in classical plaques.

Three-dimensional reconstruction and ultrastructural studies of classical plaques from the cortex of patients with Alzheimer's disease showed that microglial cells of the plaques are the amyloid-forming cells. The amyloid star of the single plaque represents the product of five or six microglial cells covering about 80% of the amyloid star surface. The amyloid fibers appear to be formed within altered cisterns of the endoplasmic reticulum. Distended cisterns form channels filled with amyloid fibers. Numerous vesicles derived from the Golgi apparatus appear to be attached to or fused with the amyloid-filled channels. Reconstruction of the amyloid star and the microglia cell pole that forms the amyloid star reveals three different zones of distribution of cytoplasmic organelles and amyloid deposits. The peripheral zone comprises channels filled with loosely packed amyloid fibers arranged in a parallel manner. The transient zone consists of a mixture of fusing amyloid channels and products of disintegration of cytoplasmic pockets, dense bodies and fragments of cellular membranes. The core of the amyloid star is composed of condensed, densely packed amyloid fibers that are free of cellular debris. Formation of the three zones supports the idea that the microglia/macrophages are not phagocytes but instead are the cells manufacturing the amyloid fibers.

Aged↗
PubMed1988

Association of monoclonal antibody-recognized antigen with steroid receptors in gynecologic tumors.

In an attempt to differentiate between the biochemical characteristics of hormonal-dependent and independent gynecologic tumors, monoclonal antibodies (mABs) MBr1 and MBr3 were used to detect tumor antigens. Steroid receptors and MBr1 and MBr3 determinants were assayed independently in a double-blinded manner. Of the 45 gynecologic tumors analyzed, 16 of 20 (80%) with both progesterone receptors (PR) (greater than 10 fm/mg protein) and estrogen receptors (ER) (greater than 5 fm/mg protein) also contained high levels of MBr1 determinant. However, these receptors were not quantitatively related to MBr1 activity. The 15 of 17 (88%) tumors that contained receptors below the discriminant levels also had low or undetectable levels of MBr1 activity. In tumors where only either PR or ER was present, 2 of 2 PR+/ER- tumors and 2 of 6 PR-/ER+ tumors expressed MBr1 antigen. No relationship of MBr3 antigenic activity to the receptors was established. These results show that MBr1-recognized antigen is expressed largely in steroid receptor-positive tumors and these data suggest that either the antigen itself or its carrier protein may be regulated by estrogen. Like steroid receptors, MBr1 antigens may have important prognostic value in gynecologic tumors.

Antibodies, Monoclonal↗
PubMed1987

An immunosuppressive factor interacts with membrane glycolipid asialo-GM1 structure.

An immunosuppressive factor was isolated from sheep-erythrocyte hyperimmunized mouse serum. Possibilities of the adsorption of the immunosuppressive factor with glycolipid asialo-GM1 incorporated liposome (dipalmitoyl lecithin) and the blockade of immunosuppressive activity by specific anti-asialo-GM1 incorporated antibody were tested. We report here that: The immunosuppressive activity of the immunosuppressive factor decreased quantitatively if the factor was preincubated with asialo-GM1 incorporated liposome (GALP) as compared with that preincubated with liposome (LP) alone; and the presence of specific anti-asialo-GM1 antibody is able to protect in vitro anti-sheep erythrocyte (SRBC) response from the suppressive effect of the immunosuppressive factor in a dose-dependent fashion under similar cell culture condition. The results indicate that asialo-GM1 may be related to the receptor of immunosuppressive factor.

Animals↗
PubMed1985

Fluorometric ELISA method for rapid screening of anti-estrogen receptor antibody production in hybridoma cultures.

A micro-fluorometric ELISA which required only 50 microliter of reagent in each step is reported here for rapid detection of anti-estrogen receptor (ER) antibody production by hybridoma cultures. In this study, several factors which influence the sensitivity of ELISA, e.g., incubation time, substrates, microtiter plates, concentration of coating antigens, choice and concentration of specific antibody and enzyme were evaluated. We observed that micro-fluorometric ELISA using 4-methylumbelliferyl phosphate-phosphatase system and MicroFluor W plates was the most sensitive; it detected readily 1 ng coating antigens or 1 ng antibody during a 15 min incubation. This system was used successfully for the detection of anti-ER antibodies in mouse immune sera, and in spent media from in vitro immunized spleen cells or hybridoma cells. This method is simple, sensitive, rapid and reliable for ER or anti-ER antibody determination.

Animals↗
PubMed1985

Correlation between immunosuppressive activity and translation regulatory activity.

An immunoglobulin negative material from the eluate of an anti-idiotype immunosorbent column [1] exhibited potent immunosuppressive activity. This material also inhibited the translation of globin mRNA in a cell-free reticulocyte lysate system. The translation inhibitory activity of this material was not attributable to nucleases which were separable by a blue-dextran agarose column. Further correlation between immunosuppressive activity and translation inhibitory activity was observed when GTP or GTP analogue was included in experimental systems. These results suggest that the immunosuppressive factor (or factors) may contain a translation inhibitory factor. The biochemical mechanism of immunosuppression is discussed.

Animals↗
PubMed1983

A monoclonal antibody showing cross-reactivity toward three calmodulin-dependent enzymes.

The spleen cells of a Balb/c mouse immunized with purified bovine calmodulin-dependent cyclic nucleotide phosphodiesterase were fused with nonsecreting mouse myeloma cells (P3-X63-Ag8-653). Antibody producing hybridomas were screened by the enzyme-linked immunosorbent assay using purified phosphodiesterase as the antigen. One monoclonal cell line, CR-B1, was found to produce antibodies which showed positive enzyme-linked immunosorbent assay reactions with bovine brain calcineurin and rabbit muscle phosphorylase kinase in addition to phosphodiesterase. The antibody was purified and characterized. It was shown to immunoprecipitate the calmodulin (CaM)-dependent phosphodiesterase and phosphorylase kinase activities but not those of CaM itself, CaM-independent phosphodiesterase and the catalytic unit of cAMP-dependent protein kinase. The immunoprecipitation of phosphodiesterase could be inhibited by calcineurin and phosphorylase kinase. These results suggest that the antibody interacts at a common site on these calmodulin-dependent proteins. The antigenic determinant in phosphodiesterase does not appear to reside in the calmodulin-binding domain of the enzyme since the antibody and phosphodiesterase interaction is not inhibited by calmodulin, and the calmodulin activation of phosphodiesterase is not affected by CR-B1 antibody. It is therefore suggested that the structural similarity among the three calmodulin-dependent proteins extends beyond the calmodulin-binding domains.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1983

On the mechanism of interaction between calmodulin and calmodulin-dependent proteins.

Molecular and kinetic studies of the interaction between calmodulin and calmodulin-dependent proteins have been reviewed. Several calmodulin-dependent proteins have been purified to homogeneity and characterized in terms of subunit structure in recent years. The results indicate that these proteins do not contain a common subunit as the basis of calmodulin binding. A monoclonal antibody capable of interacting with several calmodulin-dependent proteins has been obtained, suggesting that these proteins contain common structure. It seems that hybridoma technology may be used for probing calmodulin-binding domains in the calmodulin-dependent proteins. Using a fluorescent-labelled cyclic nucleotide phosphodiesterase, the interaction between calmodulin and the enzyme in the absence of Ca2+ can be demonstrated, and the equilibrium constant of the reaction can be determined. The study further defines the multiple interactions in the activation of the cyclic nucleotide phosphodiesterase by Ca2+ and calmodulin. Previous kinetic results along with the present results are summarized and used to elucidate the regulatory significance of the multiple Ca2+-binding of calmodulin.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗