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Biomedical subjects

X Zhuang

Publications and source records attributed to X Zhuang.

36 records · Page 2Linked to original sources
PubMed2000

[A case - control study of gallstone disease in female population in Taicang].

OBJECTIVE: To investigate the risk factors of gallstone disease in female population in Taicang. METHODS: A case - control study conducted on 144 cases and 371 controls aged 35 - 79 years in five villages. Diagnosis of gallstone disease was assessed by real - time ultrasonography. The case was considered as presence of gallstones at echograph and previous cholecytectomy. The controls were selected from a random sample of female participates. RESULTS: Through univariate and multivariate analysis, gallstone disease was significantly associated with age (OR = 1.80), family history of gallstone disease (OR = 3.66), hypertension (OR = 1.93), fat intake (OR = 1.77), number of pregnancies (OR = 1.44) and menopause (OR = 1.67). Drinking water from deep well (OR = 0.54) was inversely associated with gallstone disease. CONCLUSION: The main risk factors of female gallstone disease were age, family history of gallstone disease, fat intake, number of pregnancy and menopause. Drinking water from deep well was a protective factor of gallstone disease.

Adult↗
PubMed2000

[The prognostic significance of expression of c-met oncogene and its relation to gastric mucosal lesions].

OBJECTIVE: To determine whether there is a relationship between the expression of c-met oncogene and the stage of gastric mucosal lesions or the prognosis of gastric carcinomas. METHODS: Expression of c-met was investigated in 169 gastric mucosal lesions by using immunohistochemistry. Survival analysis was studied with the Kaplan-Meier test. RESULTS: For chronic superficial gastritis, chronic atrophic gastritis, intestinal metaplasia, dysplasia, early gastric carcinomas and advanced gastric carcinomas, the expression rates were 23.5%, 36.8%, 51.5%, 61.3%, 66.7% and 73.7% respectively. The positive rate was higher in intestinal metaplasia, dysplasia and gastric carcinomas than in chronic superficial gastritis (P < 0.05). Expression of c-met increased with the increasing proliferation of gastric mucosa in rank correlation test, which showed a close relationship (P < 0.01). Expression of c-met correlated significantly with histologic type, serosal invasion and lymph node metastases. In particular, the expression of c-met was significantly higher in Borrmann type IV gastric carcinomas (87.5%) than in early gastric carcinomas (66.7%) or Borrmann type I, II (68.7%, P < 0.01). The survival rate of patients with expression of c-met was significantly lower than that of patients without c-met expression. CONCLUSION: The expression of c-met is associated with proliferation and malignant transformation of gastric mucosa. These results suggest that expression of c-met might be a new prognostic factor in gastric carcinoma.

Cell Proliferation↗
PubMed2000

[Preliminary echocardiographic evaluation on prosthetic valve replacement of preserving the subvalvular apparatus with artificial chorade for mitral stenosis].

The purpose of this study was to evaluate the preliminary results after prosthetic valve replacement of preserving the subvalvular apparatus with artificial chorade for mitral stenosis. 20 patients had received operation with expanded polytetrafluoroethylene(e-PTFE) as artificial chordade. The patients were followed up by means of echocardiography. The time of follow-up study varied from 4 to 18 months with a mean of 6 months. The left atrial, ventricular dimension as well as ventricular function were assessed. In addition, the length of artificial chorade and obstruction of left ventricular outflow track were observed. The results showed that left atrial diameter (LAD, from 57.59 +/- 13.51 mm to 47.05 +/- 9.55 mm), left ventricular end-diastolic dimension (LVEDD, from 46.23 +/- 12.56 mm to 42.41 +/- 10.86 mm), left ventricular end-systolic dimension (LVESD, from 33.50 +/- 10.20 mm to 29.68 +/- 8.40 mm) decreased (P < 0.01), and ejection fraction (EF, from 52.59 +/- 11.89% to 58.36 +/- 8.03%) increased (P < 0.05) after operation. There were no significant changes of fractional shortening (FS, from 29.23 +/- 8.99% to 31.05 +/- 6.08%). The length of artificial chorade ranged from 2.6 cm to 4.3 cm (the mean, 3.2 cm). There was no case of obstruction of left ventricular outflow track. It is believed that the result of preliminary echocardiographic observation on prosthetic valve replacement of preserving the subvalvular apparatus with artificial chorade for mitral stenosis is satisfactory.

Adult↗
PubMed1999

Ligand-induced conformational changes observed in single RNA molecules.

We present the first demonstration that fluorescence resonance energy transfer can be used to track the motion of a single molecule undergoing conformational changes. As a model system, the conformational changes of individual three-helix junction RNA molecules induced by the binding of ribosomal protein S15 or Mg(2+) ions were studied by changes in single-molecule fluorescence. The transition from an open to a folded configuration was monitored by the change of fluorescence resonance energy transfer between two different dye molecules attached to the ends of two helices in the RNA junction. Averaged behavior of RNA molecules closely resembles that of unlabeled molecules in solution determined by other bulk assays, proving that this approach is viable and suggesting new opportunities for studying protein-nucleic acids interactions. Surprisingly, we observed an anomalously broad distribution of RNA conformations at intermediate ion concentrations that may be attributed to foldability differences among RNA molecules. In addition, an experimental scheme was developed where the real-time response of single molecules can be followed under changing environments. As a demonstration, we repeatedly changed Mg(2+) concentration in the buffer while monitoring single RNA molecules and showed that individual RNA molecules can measure the instantaneous Mg(2+) concentration with 20-ms time resolution, making it the world's smallest Mg(2+) meter.

Base Sequence↗
PubMed1999

Distribution and local differentiation of mast cells in the parenchyma of the forebrain.

Mast cells are found in the brain of many species. Although a considerable body of information is available concerning the development and differentiation of peripheral mast cells, little is known about brain mast cells. In the present study, the ontogeny of mast cells in the dove brain was followed by using three markers: acidic toluidine blue, alcian blue/safranin, and an antiserum to gonadotropin-releasing hormone (GnRH). Mast cells first appear in the pia on embryonic day (E)13-14 in ovo, then along blood vessels extending from the pia into the telencephalon on posthatch day 4-5, and in the medial habenula at week 3. Medial habenular mast cell numbers increase during development, peaking in peripubertal birds, and declining thereafter. Several measures indicate that mast cells mature within the medial habenula: there is an increase in the intensity of metachromasia, a switch from alcian blue granules in young animals to mixed alcian blue and safranin granules in older animals, and an increase in GnRH-like immunoreactivity. These results were extended by using electron microscopy. The architecture of mast cell granules evolved from electron lucent with small electron dense deposits at E15 to more electron dense granules with complex patterns of internal structure by 2 months. Ultrastructural immunocytochemistry for the GnRH-like peptide at 1 month revealed both immunopositive and negative cells, suggesting that the acquisition of this phenotype is not simultaneous across the population. Thus, immature mast cells infiltrate the central nervous system and undergo in situ differentiation within the neuropil.

Animals↗
PubMed1999

Altered emotional states in knockout mice lacking 5-HT1A or 5-HT1B receptors.

Dysfunctions of the serotonergic system have been implicated in a number of psychiatric disorders including depression, anxiety and disorders of impulse control. To model these disorders we have generated mice with altered serotonergic systems. Specifically, we have created mice that lack or express reduced levels of two serotonin receptors: 5-HT1A and 5-HT1B receptors. These receptors are localized both on serotonergic neurons where they act as autoreceptors and on non-serotonergic neurons. As a result, the 5-HT1A and 5-HT1B receptors control the tone of the serotonergic system and mediate some of the postsynaptic effects of serotonin. Agonists of these receptors are currently used in the treatment of migraine and anxiety disorders. Mice lacking these receptors develop, feed, and breed normally and do not display any obvious abnormalities. However, when analyzed in a number of behavioral paradigms, the 5-HT1A and 5-HT1B knockout mice display a number of contrasting phenotypes. While the 5-HT1B knockout mice are more aggressive, more reactive, and less anxious than the wild-types, the 5-HT1A knockouts are less reactive, more anxious, and possibly less aggressive than the wild-types. We are currently investigating with tissue-specific knockout mice which neural circuits are responsible for these phenotypes.

Animals↗
PubMed1999

Increased exploratory activity and altered response to LSD in mice lacking the 5-HT(5A) receptor.

In order to determine the distribution and function of the 5-HT5A serotonin receptor subtype, we generated knockout mice lacking the 5-HT5A gene. Comparative autoradiography studies of brains of wild-type (wt) and 5-HT5A knockout (5A-KO) mice revealed the existence of binding sites with high affinity for [125I]LSD that correspond to 5-HT5A receptors and that are concentrated in the olfactory bulb, neocortex, and medial habenula. When exposed to novel environments, the 5A-KO mice displayed increased exploratory activity but no change in anxiety-related behaviors. In addition, the stimulatory effect of LSD on exploratory activity was attenuated in 5A-KO mice. These results suggest that 5-HT5A receptors modulate the activity of neural circuits involved specifically in exploratory behavior and suggest that some of the psychotropic effects of LSD may be mediated by 5-HT5A receptors.

Animals↗
PubMed1998

Effect of procaine hydrochloride on cyanide intoxication and its effect on neuronal calcium in mice.

Cyanide intoxication in mice can be antagonized by the local anesthetic, procaine HCI, either alone or in combination with sodium nitrite and/or sodium thiosulfate. Antitoxic potency, derived from LD50 values, was compared in groups of mice pretreated with sodium nitrite (43.9 mg/kg i.p.), sodium thiosulfate (1 g/kg i.p.), and procaine HCI (37.0 mg/kg i.p.) either alone or in various combinations. The results of present study indicated that procaine HCI provides a significant protection against the lethal effects of potassium cyanide. Dose-response studies revealed procaine hydrochloride pretreated 3 min before KCN, at doses of 18.48-73.9 mg/kg, produced significant elevation of KCN LD50, moreover it has a good dose-effect relationship, but its antidotal effect was weaker than sodium nitrite or sodium thiosulfate when they were administered alone. The protective effect of sodium nitrite and sodium thiosulfate was enhanced with procaine HCI. When procaine was administered in combination both with sodium nitrite and sodium thiosulfate, its protective effects were further enhanced. Its antitoxic potency is 6.22. The effects of procaine on antagonizing the cyanide-induced whole-brain total calcium increase were also studied. KCN (7 mg/kg i.p.) significantly increased whole-brain total calcium level from 28.37 +/- 0.75 to 48.05 +/- 1.06 mg/g dry wt within 30 min, which can be prevented by procaine pretreated 15 min before KCN. One of the possible mechanism of procaine on antagonizing cyanide toxicity seems, at least, related to its effect on inhibiting the cyanide-induced neuronal calcium increase and maintaining the homeostasis of neuronal calcium.

Anesthetics, Local↗
PubMed1997

Mast cell number and maturation in the central nervous system: influence of tissue type, location and exposure to steroid hormones.

While it is well established that brain mast cells are usually associated with the cerebral vasculature, in ring doves mast cells lie directly in the neuropil of the medial habenula. During normal development mast cells enter the habenula and complete their differentiation in situ. In the present study, we asked what characteristics of the medial habenula contribute to mast cell entry and differentiation. Grafts of embryonic habenula or control optic tectal grafts were placed in the lateral ventricle or anterior chamber of the eye. Transplantation alters the location of the habenula as well as its neural and vascular connections. Three groups of hosts were used for the ventricular grafts: four-month-old and killed three months after transplantation; four-month-old and killed seven months later, and two- to three-year-old gonadectomized males killed three months later. Hosts for the intraocular grafts were four months of age and killed three months later. Mast cells were present in the habenular grafts but not in the control tissue. Mast cells in three- and seven-month-old grafts were phenotypically immature when compared to those of hosts. They contained fewer metachromatic granules, fewer granules immunoreactive to an antiserum against gonadotropin-releasing hormone, and no highly-sulphated proteoglycans. As previously described, gonadectomized adults had fewer mast cells in their medial habenula than did intact animals, but there was no change in mast cell number in habenular grafts. The current experiments indicate that the occurrence and survival of mast cells can occur within the microenvironment of the medial habenula, but that maturation of these cells requires the normal connections of this nucleus. Furthermore, gonadectomy appears to alter mast cell number in the medial habenula by generating a secondary signal which the transplanted tissue is incapable of receiving or processing.

Aging↗
PubMed1996

Brain mast cell degranulation regulates blood-brain barrier.

Mast cells synthesize vasoactive agents and a number of neurotransmitters. They are particularly numerous in the medial habenular region of the epithalamus, the attachment site of the choroid plexus. The present study examined whether degranulation of brain mast cells alters the permeability of the blood-brain barrier (BBB). To this end, doves were injected intramuscularly with the mast cell degranulator, compound 48/80 (C40/80), followed by i.v. injection of Evans blue. The distribution of the dye in the parenchyma was examined using digital imaging. Three brain areas were analyzed: the medial habenula (which also contains mast cells), the paraventricular nucleus (PVN, which abuts the third ventricle, but has no mast cells), and the lateral septal organ (LSO, a circumventricular organ with fenestrated capillaries). Significantly more Evans blue tracer and fewer toluidine blue-positive mast cells were detected in the medial habenula of subjects treated with C48/80 compared to saline controls. Evans blue did not enter the PVN in either the experimental or control group, while it entered the LSO equally in both. Degranulation of mast cells after C48/80 treatment was confirmed histochemically and ultrastructurally. The results support the hypothesis that brain mast cell degranulation locally alters BBB permeability. Activation of brain mast cells may provide a mechanism for regulated opening of the BBB.

Animals↗
PubMed1994

Reconstitution of SCID mice with human lymphoid and myeloid cells after transplantation with human fetal bone marrow without the requirement for exogenous human cytokines.

Investigation of human hematopoietic maturation has been hampered by the lack of in vivo models. Although engraftment of irradiated C.B-17 scid/scid (SCID) mice with human progenitor cells occurred after infusion with human pediatric bone marrow cells, significant engraftment of the mouse bone marrow with human cells was dependent upon continuous treatment with exogenous human cytokines. Furthermore, despite cytokine treatment, only minimal peripheral engraftment of these mice with human cells was observed. In the present study, after infusion of irradiated SCID mice with pre-cultured human fetal bone marrow cells (BM-SCID-hu mice), their bone marrow became significantly engrafted with human precursor cells and their peripheral lymphoid compartment became populated with human B cells and monocytes independently of the administration of extraneous human cytokines. Examination of the bone marrow of the BM-SCID-hu mice for human cytokine mRNA gene expression demonstrated human leukemia inhibitory factor mRNA and interleukin 7 mRNA in nine of nine BM-SCID-hu mice and macrophage-colony-stimulating factor mRNA in seven of eight BM-SCID-hu mice. This was an intriguing observation because these cytokines regulate different stages of human hematopoiesis. Since engraftment occurs in the absence of exogenous cytokine treatment, the BM-SCID-hu mouse model described should provide a useful in vivo system for studying factors important in the maturation of human myeloid and lymphoid cells in the bone marrow and the behavior of the mature human cells after dissemination into the peripheral lymphoid tissue.

Animals↗
PubMed1994

Mast cells with gonadotropin-releasing hormone-like immunoreactivity in the brain of doves.

Using an antiserum (LR-1) raised against mammalian gonadotropin-releasing hormone (GnRH), we previously identified a nonneuronal cell that was more numerous in the medial habenula (MH) of courting ring doves than in individuals housed in visual isolation. The current studies suggest that they are mast cells. Both acidic toluidine blue and toluidine blue dissolved in water/butanediol revealed metachromatic cells with a distribution and morphology similar to that obtained by immunostaining with the GnRH antiserum in the MH. Some cells had granules reactive to safranin in the presence of alcian blue, indicative of a highly sulfated proteoglycan of the heparin family. Immunocytochemical studies demonstrated that all MH cells containing GnRH-like immunoreactivity contained histamine, another mast cell marker. The GnRH-immunoreactive cells had a unilobular, ovoid nucleus. Secretory granules within the cells were electron dense and displayed a variety of internal structures. Fine filamentous processes appeared evenly distributed on the cell surface whether cells were located on the pial surface or within the brain parenchyma. All of these features are characteristic of mast cells. To test whether the epitope recognized by the GnRH antiserum was produced by the mast cells or endocytosed from the cerebrospinal fluid, an iodinated GnRH analog was injected intracerebroventricularly at the initiation of courtship. Radioautography revealed no radioactive cells in the brain, indicating that the GnRH antibody recognized a molecule synthesized by the nonneuronal cells rather than internalized by a receptor-mediated mechanism. These observations suggest an interaction between a component of the immune network and specific regions of the central nervous system.

Animals↗
PubMed1994

Disseminated human immunodeficiency virus 1 (HIV-1) infection in SCID-hu mice after peripheral inoculation with HIV-1.

A small animal model that could be infected with human immunodeficiency virus 1 (HIV-1) after peripheral inoculation would greatly facilitate the study of the pathophysiology of acute HIV-1 infection. The utility of SCID mice implanted with human fetal thymus and liver (SCID-hu mice) for studying peripheral HIV-1 infection in vivo has been hampered by the requirement for direct intraimplant injection of HIV-1 and the continued restriction of the resultant HIV-1 infection to the human thymus and liver (hu-thy/liv) implant. This may have been due to the very low numbers of human T cells present in the SCID-hu mouse peripheral lymphoid compartment. Since the degree of the peripheral reconstitution of SCID-hu mice with human T cells may be a function of the hu-thy/liv implant size, we increased the quantity of hu-thy/liv tissue implanted under the renal capsule and implanted hu-thy/liv tissue under the capsules of both kidneys. This resulted in SCID-hu mice in which significant numbers of human T cells were detected in the peripheral blood, spleens, and lymph nodes. After intraimplant injection of HIV-1 into these modified SCID-hu mice, significant HIV-1 infection was detected by quantitative coculture not only in the hu-thy/liv implant, but also in the spleen and peripheral blood. This indicated that HIV-1 infection can spread from the thymus to the peripheral lymphoid compartment. More importantly, a similar degree of infection of the hu-thy/liv implant and peripheral lymphoid compartment occurred after peripheral intraperitoneal inoculation with HIV-1. Active viral replication was indicated by the detection of HIV-1 gag DNA, HIV-1 gag RNA, and spliced tat/rev RNA in the hu-thy/liv implants, peripheral blood mononuclear cells (PBMC), spleens, and lymph nodes of these HIV-1-infected SCID-hu mice. As a first step in using our modified SCID-hu mouse model to investigate the pathophysiological consequences of HIV-1 infection, the effect of HIV-1 infection on the expression of human cytokines shown to enhance HIV-1 replication was examined. Significantly more of the HIV-1-infected SCID-hu mice expressed mRNA for human tumor necrosis factors alpha and beta, and interleukin 2 in their spleens, lymph nodes, and PBMC than did uninfected SCID-hu mice. This suggested that HIV-1 infection in vivo can stimulate the expression of cytokine mRNA by human T cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1993

Reproductive behavior, endocrine state, and the distribution of GnRH-like immunoreactive mast cells in dove brain.

Previous studies indicate that there is an increase in the number of detectable mast cells expressing gonadotropin-releasing hormone-like immunoreactivity (GnRH-ir) in the medial habenular region of the brain in ring doves after a period of 2 hr of courtship. In the present experiment the overall distribution of GnRH-ir mast cells in the brain is described, and the influence of behavioral and endocrine state on brain mast cell distribution and detectable mast cell number is explored. Four groups of male birds were studied: (1) paired with a female and displaying courtship behavior, (2) paired with a squab and displaying aggressive behavior, (3) visually isolated from other doves, and (4) long-term castrates housed communally. In all four groups, GnRH-ir mast cells were observed in the following areas: the medial habenula, circumventricular organs, organum vasculosum lamina terminalis and organum subseptale, the pia mater, and blood vessels. Cell counting revealed differences among groups in numbers of habenular mast cells. Courted doves had the most habenular mast cells, followed by doves paired with squabs, and then visually isolated doves, while castrates had the fewest. One-way ANOVA indicates significant differences among groups. All pairwise comparisons show that the courting animals had significantly more detectable mast cells in the habenular area than did visually isolated and castrated groups. These results suggest that the appearance and/or detectability of GnRH-ir mast cells in the habenula is related to the behavioral state and possibly to the endocrine state of the animal and suggest a novel mechanism for interactions among the nervous, endocrine, and immune systems.

Aggression↗
PubMed1992

Design of polymerase chain reaction primers for the selective amplification of HIV-1 RNA in the presence of HIV-1 DNA.

OBJECTIVE: To develop a sensitive method for the specific detection of HIV-1 RNA. DESIGN: Following reverse transcription, the presence of HIV-1 RNA can be detected by polymerase chain reaction (PCR) amplification. Since specific detection of HIV-1 RNA may be complicated by contamination with minute quantities of HIV-1 DNA, samples are treated with deoxyribonuclease (DNase) prior to analysis. This additional step increases the possibility of RNA degradation and sample contamination. METHODS: A primer, HG141, was designed to hybridize to the poly(A) tract present in HIV-1 genomic and all HIV-1 messenger (m) RNA with its 5' end and to the region upstream of the poly(A) tract with its 3' end. The increased stability of the HG141 primer/HIV-1 RNA or complementary (c) DNA complex, enabled PCR amplification to be performed with HG141 and the return primer HG62 at an annealing temperature above the melting temperature (Tm) of the primer-HIV-1 DNA complex. RESULTS: After reverse transcription of samples obtained from HIV-1-infected H9 cells, HG62/141-primed PCR amplification specifically detected HIV-1 RNA sequences without the need for DNAase pre-treatment. This technique was more sensitive for the detection of HIV-1 RNA than SK38/39-primed PCR amplification of DNase-treated samples. CONCLUSIONS: Since the presence of HIV-1 RNA is indicative of HIV-1 replication for the presence of HIV-1 virions, the RNA-specific primer described should facilitate the assessment of HIV-1 replication and the plasma HIV-1 viral load in HIV-1-infected individuals. This should prove useful in the evaluation of the effects of therapeutic interventions on HIV-1 infection.

Base Sequence↗