Biomedical subjects
Publications and source records attributed to C Zhou.
OBJECTIVE: To investigate the causing of keloids of the earlobes. METHOD: We have treated 41 keloides of earlobes in 28 cases, and analyzed the factors. RESULT: It has been found that infections, inappropriate supporter, allergy to nickel and gold, local delayed allergy are the chief factors to form keloides of the earlobes. CONCLUSION: Some measures to prevent those cousing mentioned above have been proposed.
OBJECTIVE: To access the development of posterior vitreous detachment(PVD) related to age, axial length of the eye, vitreous changes as well as the myopic chorioretinal manifestation in patients with high myopia. METHODS: The vitreous status of 61 consecutive patients with high myopia(> or = -8.0 D and axial length > or = 26.0 mm) 110 eyes and 68 controls (< or = -3.0 D) 119 eyes were examined with biomicroscopic slit lamp and B-scan ultrasound. The myopic chorioretinal changes at the posterior pole were examined by indirect ophthalmoscope. The axial length of the eye was measured by A-scan ultrasound. The incidence of PVD was evaluated by Chi-square test. RESULTS: The incidence of PVD in patients with high myopia increased with age. Its overall incidence was significantly higher than that in the controls (78.2% vs 31.1%, P < 0.001). In addition, the onset of PVD in patients with high myopia occurred much earlier in age than that in the control group. Axial length was an important factor responsible for the development of PVD in patients with high myopia. The incidence of PVD and age were highly correlated (r = 0.9997, P < 0.05). Retinal detachment occurred in 5 eyes in the patients with high myopia. CONCLUSIONS: The results in the present study suggested that the incidence of PVD in patients with high myopia, increased with axial length of the eye and age. Vitreous changes are characteristic findings associated with high myopia, which was also involved in the development of PVD.
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This paper studies interference factors in the analysis of mineral elements in salt by FAAS and discusses the problems of background interference, Cl- interference, Na+ interference and other ion interferences. K, Na, Mg, Cu, Mn, Zn, Fe, Pb, Cr and Cd in commercial salt were determined. The results showed that this method did not suit Cr,background absorption only interfered with the determination of K, and Mg, 1% Cl- interfered with the determination of K, and 10% Cl- or 2% Na+ interfered with the other elements. After technical treatment and eliminating all sorts of interferences, the results of analysis for salt are satisfactory.
Phosphatidylinositol-specific phospholipase C (PI-PLC) from Bacillus thuringiensis is an allosteric enzyme with both a phospholipid activator site and an active site. The activation of PI-PLC enzyme is optimal with phosphatidylcholine (PC) binding to the activator site and anchoring the enzyme to the interface [Zhou, C., et al. (1997) Biochemistry 36, 347-355; Zhou, C., et al. (1997) Biochemistry 36, 10089-10091]. In contrast to PC, anionic short-chain phospholipids with smaller headgroups [phosphatidylmethanol (PMe) and phosphatidic acid (PA)] as well as phosphatidylglycerol (PG) can bind to both sites playing dual roles: nonessential activation and competitive inhibition of cyclic-(1, 2)-inositol phosphate hydrolysis. PG is also a substrate, albeit a poor one, for PI-PLC, and is cleaved slowly to form alpha-glycerol phosphate. Analysis of enzyme kinetics using cIP as the substrate coupled with effects of different short-chain phospholipids on enzyme intrinsic fluorescence indicates that anionic phospholipids with small headgroups bind to the two sites with different affinities. If no interface is present, all dihexanoylphospholipids bind to the activator site more strongly than to the active site. When the activator site is occupied, it is likely that the enzyme undergoes a conformational change that allows phospholipids to bind easily to the active site. Such behavior is consistent with the observation that enzyme activation is detected at low short-chain anionic phospholipid concentrations with inhibition observed at higher concentrations, and that only inhibition is seen with these phospholipids added as monomers in the presence of a PC interface that optimally activates the PI-PLC. A kinetic model is used to extract the affinity of short-chain lipids for the active site from experimental data.
BACKGROUND: There are few reports on the cytologic features of small cell carcinoma (SMCC) of the uterine cervix. METHODS: The clinical records, histopathology, and available cervical smears from all cases of SMCC of the uterine cervix in the files of the British Columbia Cancer Agency between 1985 and 1997 were reviewed. RESULTS: Cervical smears were available from 11 of 13 identified cases. Six cases had a pretreatment smear containing numerous definitely malignant cells. In the seven cases with reported negative smears, review of the most recent smears detected a missed high grade squamous intraepithelial lesion in one case and rare suspicious epithelial cells in a second case. These two cases were considered to be false-negative smears on review. None of the six malignant smears were diagnosed as SMCC on cervical smears. These smears were reported as malignant epithelial cells, not otherwise specified in three cases and misclassified as adenocarcinoma in three cases. These malignant smears contained cells dispersed as single cells or arranged as loosely cohesive sheets or gland-like aggregates. Tumor cells, ranging from small to large, had extremely pleomorphic, angulated nuclei that were hyperchromatic and showed nuclear molding and smearing. Mitotic figures were common and karyorrhectic debris was identified in all cases. CONCLUSIONS: The routine cervical smear is a relatively insensitive and nonspecific method of detecting SMCC. The specific diagnosis of SMCC on cervical smears is difficult. SMCC can mimic inflammatory cells, follicular cervicitis, endometrial cells, endocervical adenocarcinoma, squamous cell carcinoma of small cell type, non-Hodgkin's lymphoma, and other unusual malignant neoplasms. The suspicion of SMCC on a cervical smear should prompt an urgent biopsy to establish the diagnosis and initiate prompt treatment.
The effect of different phospholipids on the kinetic behavior of phosphatidylinositol-specific phospholipase C (PI-PLC) from Bacillus thuringiensis toward PI vesicles has been investigated. Cosonicated PC/PI vesicles displayed enhanced hydrolysis of PI when less than 0. 20 mole fraction PC was incorporated into the vesicle; higher mole fractions of PC led to a decrease from the maximum activity mimicking surface dilution of substrate. Since the PC could affect PI-PLC binding to vesicles, the effect of separate PC vesicles on enzymatic hydrolysis of PI vesicles was examined. Separate phosphatidylcholine vesicles were found to activate PI-PLC-catalyzed cleavage of PI vesicles up to 7-fold. The activation was completely abolished when the PC vesicle was composed of cross-linked molecules. In the absence of enzyme, fluorescence resonance energy transfer studies did not detect any fusion between PI and PC vesicles if the total lipid concentration was below 2 mM. Higher total lipid concentrations (>20 mM) increased PC transfer between PC and PI vesicles, producing a PI vesicle population with small amounts of PC in the outer monolayer. This suggested that the activation of PI-PLC toward PI vesicles reflects the time scale of transfer of PC from PC vesicles to PI vesicles. Cosonicated PC/PI vesicles provide a measure of enzyme activity versus mole fraction of PC that can be used to estimate the extent of vesicle exchange or fusion between separate vesicle pools. The effects of other phospholipid vesicles on PI-PLC hydrolysis of PI were also examined; zwitterionic lipids were activators while anionic phospholipids inhibited activity. The results indicated that PC molecules in the PI interface allosterically bind to PI-PLC and help anchor enzyme in a more active conformation to the PI interface.
Our previous studies have demonstrated that axons from grafts of embryonic entorhinal cortex (EC) can reinnervate the deafferented zones in the hippocampus and form synaptic connections with the host dentate gyrus in adult mice and rats deprived of their own entorhinal inputs. Here, we have examined the ability of the EC grafts to ameliorate deficits in spatial memory. Three months after transplantation, the grafted rats and control animals were subjected to Morris water maze testing followed by histological examination. According to the exact position of grafts in the host brain, the rats with lesion and EC transplants were divided into two groups, one with EC grafts contacting both the hippocampus and overlying neocortex (n=7, EC1) and another with EC grafts confined within the hippocampus (n=6, EC2). While EC2 rats were still as impaired as those with lesion and transplants of non-entorhinal cortex (n=10, NEC) or with lesions only (n=7, LES), the EC1 rats performed better than the LES group. In a spatial memory trial, the EC1 group made more crossings over platform site and showed more focused search behavior than EC2, LES, NEC groups. The data suggest that EC grafts could partially ameliorate the deficit in spatial learning behavior in the EC-lesioned adult rats. The requirement for the graft to contact both the neocortex and the hippocampus suggests that the functional effects may be exerted by the formation of new neocortical-EC graft-hippocampal circuits.
Grafts of embryonic entorhinal cortex (EC) or non-entorhinal cortex (NEC) were placed into the hippocampus of adult rats with transection of the perforant paths. Graft-host connectivity was investigated at 4-6 months post-transplantation by recording extracellular evoked responses in hippocampal slice preparations. Electrical stimulation of the grafts evoked excitatory postsynaptic potentials (EPSPs) in the outer molecular layer of the dentate gyrus, and the stratum lacunosum moleculare of CA1, CA3, and elicited population spikes in the granule cell layer and the pyramidal cell layer of CA1, but not CA3. While the latencies and the forms of these evoked response were similar to those in matched control slices from the normal animals, the amplitudes were smaller than normal controls. However, in the slices with NEC grafts, no such responses were recorded when stimulus was applied in similar position in the grafts. The findings suggest that grafted entorhinal neurons make viable synaptic connections with the host hippocampus.
An enhanced fluorescent fiber-optic biosensor system using ultrasonic concentration of particles and cells has been developed and applied in the detection of Salmonella typhimurium. A biosensor test chamber also serves as an ultrasonic standing-wave cell that allows microspheres or cells to be concentrated in parallel layers or in a column along the axis of the cell. A fiber probe along the axis delivers laser excitation to fluorescent-labeled antibodies of Salmonella and collects the fluorescent signal. The labeled-antibodies themselves do not respond to the ultrasound, but, when attached to Salmonella cells, the Salmonella-antibody complexes can be moved acoustically to the axis of the cell, increasing the fluorescent signal. In a second, more robust, type of immunoassay, the Salmonella-labeled-antibody complexes attach to unlabeled antibodies that have been immobilized on the surface of polystyrene microspheres. This entire structure can be manipulated acoustically and the increase in the fluorescent signal, which can be an order of magnitude, indicates the presence of Salmonella.
Mode-actions of the Na(+)-Ca2+ exchanger from genes to mechanisms to a new strategy for brain disorders were comparatively studied in oxidative stress. In transfected Chinese hamster ovary (CHO) cells steadily expressing the Na(+)-Ca2+ exchanger's gene, Ca(2+)-efflux via an active mode of the Na(+)-Ca2+ exchanger was elicited by hydrogen peroxide (H2O2) after preincubation of the cell with a Ca(2+)-free medium, whereas Ca(2+)-influx via a reverse mode of the Na(+)-Ca2+ exchanger was dramatically evoked by H2O2 after preincubation of the cell with a Ca2+ medium, as a prelude to neuronal death. According to [45Ca2+] uptake of transfected CHO cells at given time intervals or extracellular Na+[Na+]o gradients, hyperbola, logarithmic and sigmoid curve equations of the Na(+)-Ca2+ exchanger's mode-actions were respectively defined in the absence and the presence of H2O2. The Na(+)-Ca2+ exchanger's conformational transition in oxidative stress was dominated by adenosine triphosphate (ATP)-dependent cytoskeletal redox modification, cation-pi interactions and secondary Ca2+ activation. These mechanisms were used to generate an intracellulary distributed tetra-cluster (named VISA931) for rescuing G-protein agonist-sensitive signal transduction and cortico-cerebral somatosensory evoke potential (SEP) from oxidation via activating forward operation of the Na(+)-Ca2+ exchanger, the beta-adrenergic and the P2-purinergic receptors, blocking Ca2+ influx and catalyzing the dismutation of superoxide anions (O2-.) to H2O2. In conclusion, knowledge-based drug design is a new strategy for developing promising candidates of neuroprotective agents.
By using human placental acidic isoferritin (PAF) as antigen to immunize BALB/c mice and conventional cell fusion, we have established three mouse hybridoma cell lines that secrete IgG monoclonal antibodies (MAbs) to PAF, termed as Z-2-3, Z-2-5, and Z-3-6, respectively. In ELISA, the MAbs were shown to react specifically with human PAF. We then applied the polymerase chain reaction (PCR) technique to clone variable region genes of the heavy (V(H)) and light (V(L)) chains of these MAbs, and appropriate full-length cDNA clones were obtained and characterized by nucleotide sequence analysis. V(H) and V(L) segments of anti-human PAF MAbs belong to the J558 and Vkappa19 family, respectively. The nucleotide sequence of Z-3-6 in the V(H) segment is highly homologous to that of MAb 18.1.16 except for their diversity minigenes. The light chain sequences of these MAbs show high homology with that of MAb cc92. It is implied that the D segment and the nucleotides inserted at the V(H)-D and D-J splice junctions are mostly responsible for the specificity of Z-3-6, and that the differences between the V(H) and V(L) sequences of these MAbs may determine their different affinity or recognition of different antigenic determinants.
The clinical and pathologic features of 17 cases of papillary serous adenocarcinoma of the cervix (PSCC) were studied in women who ranged in age from 26 to 70 years. There was a bimodal age distribution, with one peak occurring before the age of 40 years and the second peak after the age of 65. The presenting symptoms were abnormal vaginal bleeding (11 patients), abnormal exfoliative cervical cytology (four patients), or watery vaginal discharge (two patients). On pelvic examination, eight patients had a polypoid or exophytic cervical mass and two patients had an ulcerated or indurated cervix; no abnormality was detected in seven patients. Two tumors were stage Ia, 12 were stage Ib, two were stage II, and one was stage III. Nine patients were treated by radical hysterectomy and one by simple hysterectomy; six of these patients received postoperative radiotherapy. The other patients received primary radiotherapy. On microscopic examination, all of the tumors had a complex papillary architecture with epithelial stratification and tufting. Six tumors were grade 2/3 and 11 were grade 3/3. All of the tumors had >10 mitotic figures per 10 high-power fields. An intense acute and chronic inflammatory infiltrate was typically present within the cores of the papillae and in areas of stromal invasion. Occasional psammoma bodies were present in three cases. Five of 12 tumors stained positively for p53, with six and nine of 12 tumors, respectively, immunoreactive for carcinoembryonic antigen and CA-125. Seven tumors were mixed with another histologic subtype of cervical adenocarcinoma, most commonly low-grade villoglandular adenocarcinoma. Fifteen patients were followed from 6 months to 11 years (mean 56 months). Six patients died of extensive metastases within 5 years of diagnosis; an additional patient experienced tumor recurrence with malignant ascites 2 years after diagnosis. The most common metastatic sites were pelvic and periaortic lymph nodes; other sites included cervical lymph nodes, lung, peritoneum, liver, and skin. Eight patients were alive without evidence of tumor at last follow-up. Age <65 years, stage >I, tumor size >2 cm, tumor invasion >10 mm, the presence of lymph node metastases, and elevation of serum CA-125 were associated with a poor prognosis. Tumor grade or composition (pure or mixed) did not correlate with patient outcome. Papillary serous adenocarcinoma of the cervix resembles microscopically its counterparts elsewhere in the female genital tract and peritoneum. The tumors can behave aggressively with supradiaphragmatic metastases and a rapidly fatal course when diagnosed at an advanced stage, but the outcome for patients with stage I tumors is similar to that of patients with cervical adenocarcinomas of the usual type.
OBJECTIVE: A retrospective, observational study of pregnancy outcome was performed on variables maintained in an ART database to determine factors that might affect miscarriage rate in pregnancies resulting from assisted reproduction technologies (ART). METHODS: Previously infertile couples, where conception was achieved after ART, were included. Seven hundred and ninety-four consecutive clinical pregnancies, diagnosed by ultrasound documentation of the gestation sac in the first trimester were divided into 2 groups: 'miscarriage' and 'term birth'. Differences between the groups were analysed using crosstable regression analyses or t-test in second yearly cohorts. RESULTS: A statistically significant positive relationship was seen between age and spontaneous abortion rate (p = 0.008) with a major increase after the age of 38 years. There was no significant difference in the mean number of oocytes retrieved between groups (p = 0.17). While there was a significant negative correlation between maternal age and the total number of oocytes collected (p < 0.001), there was no statistical difference between those women who miscarried or delivered a live infant. No relationships were found with any other variables analysed. CONCLUSION: Maternal age is probably the most important factor in pregnancy outcome in ART. This survey could not determine any other variables as being major prognostic determinant for miscarriage once pregnancy was attained.
The neuronal ceroid lipofuscinoses (NCLs) are a group of inherited degenerative neurological diseases affecting children. A number of non-allelic variants have been identified within the human population and the genes for some of these have recently been identified. The underlying mechanism for the neuropathology remains an enigma; however, pioneering studies with the naturally occurring ovine model (OCL) have led to the proposal that these diseases represent lesions in specific hydrophobic protein degradation pathways. In this study, we show linkage between OCL and microsatellite markers on OAR 7q13-15. Using interspecies chromosome painting we establish that OAR 7q13-15 is syntenic with human chromosome 15q21-23, the region which was recently defined as the location of a newly identified late infantile variant (CLN6). We propose that our ovine model represents a mutation in the gene orthologous to that mutated in the human late infantile variant CLN6. The ovine linkage flock, consisting of 56 families, represents a powerful resource for positional cloning of this NCL gene. The availability of such a large animal model will have important implications for experimentation in downstream corrective therapies.
Previously we have shown that hyperosmolarity increases Na(+)-myo-inositol cotransporter (SMIT) activity and mRNA levels in cultured endothelial cells. Because hyperosmolarity and cytokines, such as tumor necrosis factor-alpha (TNF-alpha), activate similar signal transduction pathways, we examined the effect of TNF-alpha on SMIT mRNA levels and myo-inositol accumulation. In contrast to the effect of hyperosmolarity, TNF-alpha caused a time- and concentration-dependent decrease in SMIT mRNA levels and myo-inositol accumulation. The effect of TNF-alpha on myo-inositol accumulation was found in large-vessel endothelial cells (derived from the aorta and pulmonary artery) and cerebral microvessel endothelial cells. In bovine aorta and bovine pulmonary artery endothelial cells, TNF-alpha activated nuclear factor (NF)-kappa B. TNF-alpha also increased ceramide levels, and C2-ceramide mimicked the effect of TNF-alpha on SMIT mRNA levels and myo-inositol accumulation in bovine aorta endothelial cells. Pyrrolidinedithiocarbamate, genistein, and 7-amino-1-chloro-3-tosylamido-2-hepatanone, compounds that can inhibit NF-kappa B activation, partially prevented the TNF-alpha-induced decrease in myo-inositol accumulation. The effect of TNF-alpha on myo-inositol accumulation was also partially prevented by the protein kinase C inhibitor calphostin C but not by staurosporine. These studies demonstrate that TNF-alpha causes a decrease in SMIT mRNA levels and myo-inositol accumulation in cultured endothelial cells, which may be related to the activation of NF-kappa B.
Activation of the cAMP signaling pathway is correlated with increased secretory-related events in a wide variety of cell types including the gastric parietal cell. Within this pathway, as well as in other intracellular signaling pathways, protein phosphorylation serves as a major downstream regulatory mechanism. However, although agonist and cAMP-dependent activation of cAMP-dependent protein kinase (PKA) has been demonstrated, little is currently known about the downstream in vivo phosphoprotein substrates of this enzyme. Here we report the isolation, microsequencing, and cloning of a LIM and SH3 domain-containing, cAMP-responsive, 40-kDa phosphoprotein (pp40) from rabbit gastric parietal cells. The deduced amino acid sequence for pp40 is 93.5%, homologous with the putative protein product of the human gene lasp-1, which was recently identified based on its overexpression in some breast carcinomas. In addition to LIM and SH3 domains, the rabbit homolog contains two highly conserved PKA consensus sequences as well as two conserved SH2 binding motifs and several other putative protein kinase phosphorylation sites, including two for tyrosine kinase(s). Combined Northern and Western blot analyses indicate that pp40/lasp-1 is widely expressed (through a single 3.3-kb message) not only in epithelial tissues but also in muscle and brain. Furthermore, stimulation of isolated parietal cells, distal colonic crypts, and pancreatic cells with the adenylyl cyclase activator forskolin leads to the appearance of a higher molecular weight form of pp40/lasp-1, a finding which is consistent with an increase in protein phosphorylation. Thus pp40/lasp-1 appears to be regulated within the cAMP signaling pathway in a wide range of epithelial cell types. Because the cAMP-dependent increase in pp40 phosphorylation is correlated with secretory responses in the parietal cell and because pp40 appears to be widely distributed among various secretory tissues, this newly defined signaling protein may play an important role in modulating ionic transport or other secretory-related activities in many different cell types.
Flavone and isoflavone phytoestrogens are plant chemicals and are known to be competitive inhibitors of cytochrome P450 aromatase with respect to the androgen substrate. Aromatase is the enzyme that converts androgen to estrogen; therefore, these plant chemicals are thought to be capable of modifying the estrogen level in women. In this study, the inhibition profiles of four flavones [chrysin (5, 7-dihydroxyflavone), 7,8-dihydroxyflavone, baicalein (5,6,7-trihydroxyflavone), and galangin (3,5,7-trihydroxyflavone)], two isoflavones [genistein (4,5,7-trihydroxyisoflavone) and biochanin A (5,7-dihydroxy-4-methoxyisoflavone)], one flavanone [naringenin (4, 5,7-trihydroxyflavanone)], and one naphthoflavone (alpha-naphthoflavone) on the wild-type and six human aromatase mutants (I133Y, P308F, D309A, T310S, I395F, and I474Y) were determined. In combination with computer modeling, the binding characteristics and the structure requirement for flavone and isoflavone phytoestrogens to inhibit human aromatase were obtained. These compounds were found to bind to the active site of aromatase in an orientation in which rings A and C mimic rings D and C of the androgen substrate, respectively. This study also provides a molecular basis as to why isoflavones are significantly poorer inhibitors of aromatase than flavones.