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Biomedical subjects

L Zhou

Publications and source records attributed to L Zhou.

At least 451 records · Page 25Linked to original sources
PubMed1996

Immunostimulation following fish oil-based parenteral nutrition in tumor-bearing rats.

Tumor-bearing (TB) and control rats were maintained for four to seven days on total parenteral nutrition (TPN) in which the lipid component (11.1% of total calories) was Intralipid or fish oil. Although no TB rats maintained on standard Intralipid-based TPN died prematurely in these experiments, one-third of the TB rats maintained on fish oil-based TPN died of bleeding complications by Day 4 of TPN infusion. The bleeding appeared to be due to the particle size in the fish oil emulsion, because a subsequent study employing a better emulsified TPN with smaller lipid particles exhibited fewer bleeding problems. Tumor growth, skeletal muscle atrophy, and gut hypoplasia were not reduced in the TB group maintained on fish oil-based TPN. However, immunosuppression observed in the Intralipid-based TPN group, as measured by mitogen response of cultured splenocytes, was significantly improved in the rats maintained on fish oil-based TPN. Levels of eicosapentaenoic acid were reduced in all rats receiving TPN. Although the hypothesized antitumor and anticachexia effects of fish oil administration were not realized, significant improvement in immunosuppression was noted. These results suggest that intravenously administered fish oil may have potential positive effects for the host.

Animals↗
PubMed1996

Normal lysosomal enzyme staining in skin tissues of patients with keratoconus.

Keratoconus is a disease characterized by thinning and scarring of the central portion of the cornea. We have shown, in corneas and conjunctival tissues obtained from patients with keratoconus, that lysosomal enzyme staining is enhanced in the epithelial layer. In this study, we examined the lysosomal enzyme staining in skin-biopsy specimens of patients with keratoconus. Tissues collected from four patients with keratoconus and six normal subjects were fixed and processed for histochemical staining. Results showed that the epidermal and dermal layers of all skin specimens stained positively for two lysosomal hydrolases, acid esterase and acid phosphatase. The enzyme staining in the skin epidermal and dermal cells of the keratoconus patients was within the normal range. The staining in the corneal and conjunctival epithelia of the same patients was more prominent than that of normal controls. It appears that the biochemical abnormality identified in keratoconus is not manifested in the skin.

Acetylesterase↗
PubMed1996

Functional in vivo studies of the Neurospora crassa cys-14 gene upstream region: importance of CYS3-binding sites for regulated expression.

Sulphate transport in Neurospora crassa is achieved by two distinct sulphate permeases, I and II, encoded by the cys-13 and cys-14 genes, respectively. The synthesis of both sulphate permeases is subject to sulphur repression and requires the global positive-acting regulatory protein CYS3, CYS3, a bZIP DNA binding protein, regulates cys-14 expression at the transcriptional level and binds in vitro specifically to three DNA-recognition sites, A, B, and C, in the cys-14 upstream region. In vivo functional analysis of the cys-14 promoter was carried out with 5' deletions and by deletions or mutations of CYS3 DNA-binding sites. The most distal CYS3-binding site, C, located 1.4kb upstream of the transcriptional start site, is necessary and sufficient to mediate strong transcriptional activation by CYS3; moreover, site C was able to function equally well when it was located at variable distances upstream of the cys-14 gene. Site B, located 1 kb upstream, alone is able to support a moderate degree of cys-14 expression. Site A is not required and does not appear to play any functional role in cys-14 expression, even though it is in close proximity to the transcriptional start site. The presence of multiple copies of CYS3-binding elements A or B in the cys-14 promoter results in a parallel increase of regulated gene expression. When a transforming cys-14 gene becomes integrated at ectopic locations in the host genome, it can be expressed in an unregulated fashion, presumably by coming under the control of other promoter elements. Our results also suggested that at least one enzyme in the sulphate catabolic pathway requires a functional CYS3 protein for expression.

Anion Transport Proteins↗
PubMed1996

Rural-to-urban migration in China.

"One consequence of economic reform in China has been the greatly accelerated migration of labour from rural areas to cities. Estimates suggest an annual migrant labour flow of around 50-60 million people, of whom 10-15 million have settled permanently in cities. This article surveys the information that has become available from a number of population and labour surveys. It covers the volume, spatial and temporal dimension of rural-to-urban migration, the characteristics of migrant labourers, the determinants of migration and the impact of migration on China's rural and urban economy."

Asia↗
PubMed1996

Inhibition of acid secretion by electrical acupuncture is mediated via beta-endorphin and somatostatin.

Electroacupuncture (EAP) was shown to inhibit basal gastric acid secretion in dogs and sham feeding-stimulated acid secretion in humans. However, its effect on a meal-stimulated acid secretion in dogs and the mechanisms involved remain unclear. In five dogs prepared with gastric cannulas, gastric acid secretion was determined by a dye-dilution technique for 60 min after intragastric administration of 200 ml of 4% mixed amino acid meal in six different experiments: study 1, no acupuncture; study 2, sham acupuncture (SAP); study 3, EAP; study 4, EAP plus naloxone; study 5, naloxone alone; and study 6, intravenous infusion of somatostatin (SS) and vasoactive intestinal peptide (VIP) at doses of 0.5 and 1.0 micrograms.kg-1.h-1, respectively. EAP was performed on three different points including Pishu, ZusanLi, and Neiguan. Biphasic electrical pulse (25-100 Hz, 12-16 mA) was applied continuously via needles for 75 min starting 15 min before meal. SAP on nonacupoints in hind- and forelegs was performed with the same electrical pulse. Plasma SS, VIP, beta-endorphin, and gastrin were determined by specific radioimmunoassays. EAP significantly inhibited acid secretion (75%; P < 0.01), which coincided with significant increases in plasma SS, VIP, and beta-endorphin and a significant decrease in plasma gastrin. Naloxone completely reversed EAP-induced inhibition of acid secretion and changes in plasma concentration of peptides. SAP also significantly suppressed acid output (30%; P < 0.05), with a modest but significant increase in plasma beta-endorphin. However, the inhibition by EAP on the acid output was significantly greater than that by SAP (P < 0.01). Furthermore, exogenous SS (0.5 microgram.kg-1.h-1) significantly inhibited acid output (78%), whereas VIP failed to inhibit gastric acid secretion. We conclude that, in dogs, EAP significantly inhibits meal-stimulated acid secretion. This acid inhibition is mediated by the release of beta-endorphin and somatostatin, and an endogenous opiate or opiates appear to play an important role in the release of SS, VIP, and beta-endorphin.

Acupuncture Therapy↗
PubMed1996

Keratinocyte growth factor stimulates CFTR-independent fluid secretion in the fetal lung in vitro.

Keratinocyte growth factor (KGF) caused cystic dilation of mouse fetal lung explants in vitro, markedly increasing the luminal volume of lung buds and disrupting branching morphogenesis. Effects of KGF were dose dependent, were detected within 4 h of treatment, and were blocked by cycloheximide but not by actinomycin D, indicating that de novo protein synthesis mediated the response. Effects of KGF were inhibited by bumetanide, an inhibitor of the Na(+)-K(+)-Cl- cotransporter, and ouabain, an inhibitor of the Na(+)-K(+)-ATPase. KGF stimulated fluid secretion equally in lung buds from cystic fibrosis transmembrane conductance regulators (CFTR) -/- and wild-type embryos, indicating that the effects were mediated by CFTR-independent Cl- transport. Microelectrode studies demonstrated that, whereas KGF did not acutely alter the transepithelial potential difference (PD) across the respiratory epithelium, the PD decreased while luminal volume increased during chronic exposure. KGF inhibited expression of alpha-subunit of epithelial Na+ channel (alpha-ENaC) mRNA, suggesting that KGF may inhibit Na+ absorption, which may contribute to KGF-induced fluid accumulation. KGF-induced fluid accumulation is driven by CFTR-independent Cl- transport and associated with decreased expression of alpha-ENaC.

Animals↗
PubMed1996

Thyroid transcription factor-1, hepatocyte nuclear factor-3beta, surfactant protein B, C, and Clara cell secretory protein in developing mouse lung.

We used immunohistochemical analysis to localize thyroid transcription factor-1 (TTF-1), hepatocyte nuclear factor-3beta (HNF-3beta), prosurfactant proteins B and C (pro-SP-B, pro-SP-C), surfactant protein B (SP-B), and Clara cell secretory protein (CCSP) in developing mouse lung. TTF-1 and HNF-3beta were expressed at the onset of lung morphogenesis (gestational Day 10) and throughout fetal lung development, being detected in the nuclei of airway epithelial cells. TTF-1 was most prominent in distal airway epithelial cells in embryonic lung and HNF-3beta in proximal bronchial and bronchiolar epithelial cells. Pro-SP-B and pro-SP-C were first detected on gestational Day 11, being localized to the cytoplasm of airway epithelial cells. Expression of both pro-proteins was confined to distal airway epithelial cells from gestational Day 12 to Day 16. From gestational Day 17 and thereafter, pro- SP-B was detectable in Type II cells and bronchiolar epithelial cells, whereas pro-SP-C was restricted to Type II cells. SP-B peptide was first detected on gestational Day 17 in the cytoplasm of Type II cells and within the lumen of distal airways. SP-B peptide was detectable only in the cytoplasm of Type II cells in adult lung. CCSP was first detected on gestational Day 17, being localized to the cytoplasm of columnar epithelial cells lining the conducting airways. Pro-SP-B, SF-B, pro-SP-C, and CCSP staining increased before birth. The early expression of TTF-1 and HNF-3beta, preceding and overlapping that of pro-SP-B, mature SP-B, pro-SP-C, and CCSP, supports a regulatory role for TTF-1 and HNF-3beta in lung-specific gene expression.

Animals↗
PubMed1996

Role of thromboxane A2, endothelin-1 and endothelin-3 in rat nephrotoxic serum nephritis.

To clarify the role of thromboxane A2 (TxA2), endothelin-1 (ET-1) and endothelin-3 (ET-3) in the progression of glomerular injury in accelerated nephrotoxic serum nephritis (NTN) in the rat, we studied the expression of ET-1 and ET-3 at the kidney by immunohistochemical method and examined the effect of a novel TxA2 receptor antagonist, S-1452. The S-1452-treated group showed significantly lowered 24-hr proteinuria and milder glomerular cell proliferation and lobulation than the non-treated group (NT group) on experimental day 10. There was no significant difference in the glomerular polymorphonuclear cell (PMN) exudation between the 2 groups. Immunofluorescent findings revealed that ET-1 and ET-3 were seen along the glomerular capillary wall and partly in the mesangial area in all rats of the NTN group. The degree and positive rate of ET-1 and ET-3 staining were significantly higher in the NTN group than in the S-1452 group. These findings suggest that TxA2 may be an important mediator in the development of NTN, and that TxA2 receptor antagonist may be useful for the reduction of glomerular injury in this type of nephritis. In addition, local production of ET may contribute to the development of this nephritis.

Animals↗
PubMed1996

Expression of wound healing and stress-related proteins in keratoconus corneas.

PURPOSE: Keratoconus is characterized by thinning and scarring of the central portion of the cornea. This study was performed on keratoconus corneas to examine the expression of proteins related to wound healing including vimentin, an intermediate filament protein, and tenascin, and extracellular matrix protein. The expression of stress-related cytokines, heat shock proteins and ubiquitin was also investigated. METHODS: Corneal buttons were collected from patients with keratoconus, normal subjects and patients with other corneal diseases such as pseudophakic bullous keratopathy. Immunofluorescence staining was performed on frozen sections for vimentin and tenascin, and immunoperoxidase staining was carried out on paraffin sections for cytokines, heat shock proteins and ubiquitin. RESULTS: To varying degrees, all proteins examined, except tenascin and heat shock protein 90, were found to be expressed in normal human corneas. The expression of vimentin, tenascin, transforming growth factor-beta, interleukin-1, heat shock protein 27, and ubiquitin was enhanced in keratoconus corneas. A similar enhancement however was also observed in other diseased corneas. CONCLUSIONS: Altered expression of several wound healing or stress-related proteins was noted in keratoconus corneas. The alterations appear to be nonspecific injury or wound responses in association with corneal diseases.

Adolescent↗
PubMed1996

Transforaminal arthroscopic decompression of lateral recess stenosis.

The purpose of this study was to evaluate the feasibility and efficacy of arthroscopic decompression of lateral recess stenosis, determine potential associated complications, and present an alternative method to access the lateral recess of the lumbar spine. Forty patients were selected in whom the authors found clinical and computerized tomography evidence of lateral recess stenosis and sequestered foraminal herniations. All 40 were treated with a posterolateral arthroscopic technique, and 38 were available for this follow-up evaluation. A satisfactory result was obtained in 31 patients (82%). No neurovascular complications were encountered; however, other complications included an infection of the disc space in one patient and a causalgic-type pain in the involved extremity in four patients. The associated postoperative morbidity in this group of patients was minimal and resulted in rapid rehabilitation and return of patients to preoperative functioning level.

Adult↗
PubMed1996

Adhesion of human trabecular meshwork cells to extracellular matrix proteins. Roles and distribution of integrin receptors.

PURPOSE: To examine the adhesion of human trabecular meshwork cells with various extracellular matrix (ECM) proteins and to evaluate the roles and distribution of integrin receptors. METHODS: Cultured human trabecular meshwork cells were added to 96-well plates either uncoated or coated with proteins including fibronectin, laminin, and vitronectin, as well as collagen types I, III, IV, V, and VI. After incubation for 1 hour, the adhesion of cells was measured. Expression of cell surface integrins was determined by cell enzyme-linked immunoadsorbent assay (ELISA) and immunoprecipitation. Distribution was visualized by immunofluorescence staining using integrin-specific antibodies. For function perturbation and peptide inhibition studies, cells were preincubated with either integrin antibodies or synthetic peptides before the adhesion assays. RESULTS: Human trabecular meshwork cells attached to plates coated with ECM proteins in a dose-dependent manner. Fibronectin, vitronectin, and collagen types I and IV were the preferred ECM substrates. Cell ELISA revealed the presence of integrins alpha 1, alpha 2, alpha 3, alpha 4, alpha 5, alpha 6, alpha v, beta 1, beta 3, beta 5, alpha 5 beta 1, and alpha v beta 3 and the absence of beta 2 and beta 4 on human trabecular meshwork cells. Results from immunostaining experiments were consistent with those from cell ELISA studies. Attachment of cells to ECM proteins was blocked by specific integrin antibodies. Cell adhesion to fibronectin and vitronectin was inhibited by peptides containing the Arg-Gly-Asp sequence. CONCLUSIONS: Extracellular matrix proteins mediate the adhesion of human trabecular meshwork cells in culture. Integrin receptors appear to have functional roles in the cell-matrix interactions.

Adolescent↗
PubMed1996

In vivo effect of high energy shock waves on growth and metastasis of the heterografted tumors of nude mice.

OBJECTIVES: To examine whether high energy shock waves (HESW) can inhibit tumor growth in vivo and whether it can promote the metastasis of the heterografted tumors of nude mice. MATERIALS AND METHODS: Observations were made on the effect of HESW on tumor growth, histological and ultrastructural (transmission electron microscope, TEM) variations and metastasis to lymph nodes and viscera in the nude mice with heterografted tumors. The Dornier HM3 lithotripter was used under the working voltage of 15 kV, the impulse number being 0, 400 and 800 respectively, the temperature of waterbath, 35-37 degrees C and the impulse rate, 60/min. RESULTS: HESW did have cytotoxic effect on tumors in vivo, including acute and chronic lethal effects and growth inhibitory effect, and it could act on levels of cell membrane, cytoplasmic organelles and nuclear chromatin. At a definite working voltage, this effect was positively proportional to the impulse number. The action mechanism of HESW in vivo might be direct mechanical damage and indirect inhibition of tumor growth as a result of causing damage to the blood supply. Histological examination showed no metastatic foci to the lymph nodes and viscera of the nude mice with the heterografted tumors. CONCLUSIONS: HESW do inhibit tumor growth in vivo, but temporarily. This observation showed no tumor metastasis in the nude mice after the impulsion of HESW, but further studies on this topic are needed. It can be predicted that HESW will become a clinical method to treat the tumors after further investigation on its mechanism of action.

Animals↗
PubMed1996

Biological consequences of thrombin receptor deficiency in mice.

The thrombin receptor (ThrR) is a membrane-bound, G-protein-coupled receptor for the serine protease thrombin. This receptor is expressed in a wide variety of cells and tissues, and elicits a range of physiological responses associated with tissue injury, inflammation, and wound repair. To achieve a better understanding of the physiological role of the ThrR, we have employed homologous recombination to create mice with a disrupted ThrR gene. Following heterozygous (+/-) intercrosses, a total of 351 surviving offspring were genotyped. Only 7% of these offspring were identified as homozygous (-/-) for the disrupted allele, indicating a profound effect on embryonic development. Paradoxically, adult ThrR-/- mice appeared to be normal by anatomical and histological analysis, including their platelet number and function. Similarly, ThrR deficiency had no detectable effect in adult ThrR-/- mice on basal heart rate, arterial blood pressure, vasomotor responses to angiotensin II and acetycholine, and coagulation parameters, even though the ThrR is expressed in many cardiovascular tissue types. In addition, the loss of ThrR function in the peripheral vasculature of adult ThrR-/- mice was confirmed by the absence of various standard hemodynamic effects of the ThrR-activating peptides SFLLRN-NH2 and TFLLRNPNDK-NH2. Our results indicate that ThrR deficiency has a strong impact on fetal development; however. ThrR-/- mice that proceed to full development display surprisingly little change in phenotype compared to the wild-type.

Animals↗
PubMed1996

Use of transgenic mice to study autocrine-paracrine signaling in lung morphogenesis and differentiation.

Transgenic mice have been useful in demonstrating critical autocrine-paracrine interactions that are mediated by polypeptide hormones and associated receptors. These systems control interactions between the pulmonary mesenchyme and epithelium that have profound influences on lung morphogenesis, cell proliferation, and differentiation and include both inhibitory and stimulatory pathways. These pathways underlie the process of branching, sacculation, and alveolar development and may be served by several redundant polypeptides and receptors that work in concert to ensure normal pulmonary development. It is also likely that the same systems are involved in the proliferation and differentiation that accompany repair following injury. It is hoped that these transgenic models will provide insight into growth factors and receptors involved in cell proliferation, differentiation, and function during pulmonary organogenesis and also will serve to clarify the role of growth factors that may influence repair following lung injury, as seen in bronchopulmonary dysplasia and pulmonary fibrosis following severe lung injury in clinical settings.

Animals↗
PubMed1996

[A study of the expression and localization of tumor necrosis factor mRNA in small intestine of rats after severe burn].

In this study, the dot blotting and in situ hybridization, collaborated with determination of contents of endotoxin and TNF in plasma, were used to study the expression and localization of TNF mRNA in the intestine. The results showed that, the expression of TNF mRNA in the small intestine increased rapidly and reached maximum at 6 h postburn, being 5.56 times higher than that of normal control. The TNF mRNA-producing cells in normal animal were mononuclear phagocytes located in lamina propria. After burn, the number of positive cells in lamina propria increased significantly, and the TNF gene-expressing cells were vascular endothelium. Many positive cells were found in the crypts of the intestine. It suggested that the expression of TNF correlated well with bacterial translocation in the early stage of burn. The mononuclear phagocytes and endothelial cells located in lamina propria and interstitial tissue were the chief TNF mRNA-producing cells in the intestine. The overproduction of TNF could provoke microvascular injury or induce the production of oxygen free radical to damage the gut mucosal barrier.

Animals↗
PubMed1996

[The development of a skin-stretching device and its clinical application].

A skin-stretching device that is designed to harness the elastic properties of the skin using incremental traction is presented. In using this device, the skin is stretched from its edges by direct linear traction. The device produces extra skin tissue rapidly, and no undermining is necessary to loosen skin, so as to close large areas of skin shortage that would otherwise have required more complicated procedures for their repair. It can be employed for a duration of 20-640 minutes, and be applied preoperatively, intraoperatively or postoperatively. 52 patients have undergone the treatment since March 1994. Six months to one year's follow-up of 27 cases demonstrated satisfactory results. The method has following advantages: easy in manipulation, saving time, safe and fewer complications.

Adolescent↗