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Biomedical subjects

X Wan

Publications and source records attributed to X Wan.

104 records · Page 6Linked to original sources
PubMed1993

Acute hepatitis B infection in aboriginal Australians.

The apparent incidence of acute hepatitis B infection in the Top End of the Northern Territory was estimated from notification data and hospital data to be 12 per 100,000 per year, with a marked difference between Aborigines (42 per 100,000) and non-Aborigines (4 per 100,000), and an odds ratio of 9.7 (95 per cent confidence intervals 3 to 33). Sixty percent of Aboriginal cases of acute hepatitis B occurred in children under 10 years of age, whereas non-Aboriginal cases occurred in adults aged 20 to 29, most with behavioural risk factors. These findings confirm the importance of immunising Aboriginal children to reduce the future incidence of hepatitis B infection and hepatoma.

Acute Disease↗
PubMed1992

Hepatitis B virus markers in children and staff in Northern Territory schools.

OBJECTIVE: To measure the prevalence of hepatitis B virus (HBV) infection in children and staff at Northern Territory schools. DESIGN: Children in Years 5-7 in 24 selected primary schools were invited, with parental consent, to provide demographic and ethnic details, and a capillary blood sample for tests for hepatitis B surface antigen (HBsAg) and antibody to hepatitis B surface antigen (anti-HBs). School staff participated on a similar basis. PARTICIPANTS: 1104 children, comprising 556 from ethnic groups (originating from the United Kingdom, Ireland and northern Europe) previously reported as "low HBV prevalence", 439 Aboriginal Australians, and 109 from "other" ethnic groups (originating from Asia, the Pacific, the Middle East and southern Europe); and 209 school staff, comprising 180 from "low HBV prevalence" ethnic groups, and 29 from Aboriginal and other ethnic groups. RESULTS: Prior HBV infection (i.e. serum positive for HBsAg or anti-HBs) was detected in 28.7% of children (46.9% of 439 Aborigines; 13.7% of the 556 children from the "low prevalence" groups and 32.1% of the 109 from the "other" groups). HBsAg was detected in 8.2% of Aboriginal children, in 0.36% of those from "low prevalence" groups, and in 1.8% of those from the "other" groups. Aboriginal children in rural schools had the highest prevalence of HBV: 5.4% were positive for both HBsAg and anti-HBs, and an additional 9.8% were positive for HBsAg alone. In urban schools, the prevalence was highest in the "other" ethnic groups. For school staff, the prevalence of HBV infection was 12.8% for those from "low prevalence" ethnic groups, and 37.9% for those from all remaining groups (including Aborigines). CONCLUSION: In the Northern Territory the prevalence of past HBV infection is high in children and school staff from ethnic groups previously known to be at higher risk of HBV infection. For students and staff from ethnic backgrounds expected to be at low risk, HBV prevalence is greater than in individuals from similar backgrounds in other parts of Australia. HBV vaccination is now offered to all infants in the Northern Territory. These results also provide a rationale for the more widespread use of HBV vaccine in other situations where significant HBV transmission might occur.

Child↗
PubMed1992

Charge dependence of the distribution of contrast agents in rat cerebral ventricles.

Previous studies of MRI contrast resulting from the intracerebral administration of several contrast agents have suggested that the distribution of these agents may be dependent on the net charge. In order to further evaluate the significance of this parameter, the distribution of both aquo and CDTA-chelated lanthanide and transition metal ions in the cerebral ventricles of rats has been evaluated based on their enhancement of MRI contrast. The agents were injected directly into the lateral ventricles of Sprague-Dawley rats. Each of five different positively charged paramagnetic metal ions tested selectively enhanced the inner cellular layers of ventricular luminal wall of the rat brain, while such enhancement was absent using the corresponding negatively charged metal-CDTA complexes. The abundance of negatively charged residues on the cell surface of the inner luminal layers is suggested to be the source of the observed charge affinity. Differences in the distribution of Mn2+ ions administered intracerebrally compared with intraperitoneal (ip) injection suggest that while the first treatment may result primarily in uncomplexed aquo ions which then interact with the luminal surface, manganese ions administered ip behave more like chelated ions and are most probably complexed to transferrin.

Animals↗
PubMed1991

[Effect of acupuncture on neuronal loss induced by axotomy in the rat hypoglossal nuclei].

It was reported previously that acupuncture promotes regeneration of rat's peripheral nerve. In order to study the effect of acupuncture on recovery of motoneuronal lesion and regeneration of central nervous system, we studied the effect of acupuncture on neuronal loss induced by axotomy in the rat hypoglossal nuclei. A total of 6 pairs of rats (acupunctured and controls in pairs) were used, (each pair of) the rats were paired of the same litter and sex. After the right hypoglossal nerves were severed, rats were reared for 14 days. In this period, we gave acupuncture therapy to the acupunctured rats but nothing to the controls. After perfusion, serial paraffin sections of brain stems of rats were cut and stained with cresyl violet. Serial sections per rat were used for counting the perikaryon of the hypoglossal nuclei. The reduced percentage of neuronal population followed axotomy was calculated. It was found that neuronal loss was less severe in acupunctured rats. Difference in the reduced percentage of neuronal population between acupunctured rats and controls was significant statistically. It was shown that acupuncture increased survival of lesioned neurons, and thus acupuncture may be helpful to the recovery of neuronal lesion. The detailed mechanism is going to be explored.

Animals↗
PubMedDate not supplied

Primary extramedullary plasmacytoma in the atria of the heart.

A rare case of primary extramedullary plasmacytoma of the heart is described. The large space-occupying tumor in the atrial wall and its associated significant pericardial effusion caused marked impairment of cardiovascular function. The diagnosis was made via intravenous biopsy. Immunohistochemistry demonstrated CD45 and kappa light chain expression. Other B-cell- and T-cell-specific lymphoid markers were negative. Elevated kappa light chain was detected in serum by immunofixation electrophoresis. The differential diagnosis of plasmacytoma should be considered in cardiac tumors when routine screening is negative with lymphoid (CD20, CD3) and soft tissue immunohistochemical markers.

Aged↗
PubMedDate not supplied

Extrauterine choriocarcinoma of the greater omentum after tubal pregnancy: case report.

Extrauterine choriocarcinoma is a rare form of gestational trophoblastic tumor. Extrauterine choriocarcinoma of the greater omentum is extremely rare in the literature. A 24-year-old female with irregular vaginal bleeding, mimicking as ectopic pregnancy, underwent emergency exploratory laparotomy and local excision of the greater omentum mass. The serum beta-human chorionic gonadotropin level decreased rapidly after operation; however, it rose up again before long. Pathology showed choriocarcinoma in the greater omentum. No evidence showed lesions on uterus. No other metastasis was found. Multiple courses of combined chemotherapy were effective for this case. Surgical excision and combined chemotherapy were effective for extrauterine choriocarcinoma of the greater omentum.

Adult↗
PubMedDate not supplied

Recyclable islet isografts: a biological insulin pump to facilitate surgery in diabetic rats.

A method is described to facilitate extensive abdominal surgery in diabetic rats using temporary renal subcapsular islet isografts. The procedure is performed in three stages--each separated by 2 wk. After each rat is made diabetic (Step 1), an isogenic islet transplant is performed beneath the left renal capsule (Step 2). Step 3 is the operative procedure, followed by a left nephrectomy. Finally, it is shown how the islet isograft can be excised from the nephrectomy specimen and "recycled" into another diabetic rat (Step 2). Using this three step process, it is possible to decrease the mortality rate following orthotropic liver transplantation in diabetic rats from 100% to about 30%. This procedure can also be used to facilitate other extensive surgical procedures in diabetic rats.

Animals↗
PubMedDate not supplied

Synergistic effects of danazol and mifepristone on the cytotoxicity of UCN-01 in hormone-responsive breast cancer cells.

BACKGROUND: 7-Hydroxystaurosporine (UCN-01) is a novel antitumor agent as well as a potent inhibitor of a variety of protein kinases with a preference to protein kinase C. Because an intimate interaction exists between PKC signaling and the ER signaling pathways, sex steroid agonists/antagonists might modulate the cytotoxicity of UCN-01. MATERIALS AND METHODS: Effects of sex steroid agonists and antagonists on the UCN-01 cytotoxicity were analyzed by MTT assay in MCF-7/WT and MCF-7/ADR, a multiple drug resistance phenotype lacking ER and PR. RESULTS: MCF-7/ADR is 23-fold more resistant to UCN-01 than MCF-7. In MCF-7/WT, danazol and mifepristone enhanced the cytotoxicity of UCN-01, while these agents did not exert any significant effects on it in MCF-7/ADR. CONCLUSION: These results suggest that danazol or mifepristone might enhance the antitumor activity of UCN-01 in hormone-dependent cancer cells by interacting with PR.

Alkaloids↗
PubMedDate not supplied

Evidence of androgen receptor expression in squamous and adenocarcinoma of the esophagus.

Androgen receptors (AR) are known to stimulate cellular proliferation in certain tumors. We have assessed the androgen receptor status of esophageal carcinoma in surgically resected specimens as well as in established human esophageal carcinoma cells lines. In these initial studies we sought to characterize the frequency of expression of androgen receptors in squamous versus adenocarcinoma and in male versus female patients, and to assess the possible influence of AR expression on survivaL We analyzed androgen receptor expression utilizing immunohistochemistry in adenocarcinoma and squamous cell carcinoma of the esophagus in surgical specimens from 25 patients treated at Johns Hopkins Bayview Medical Center. Tumors in 7 of 21 males (33%) and 1 of 4 females (25%) showed positive androgen receptor staining with the monoclonal body antibody AR 441. There was no suggestion of a difference in expression of AR between males and females. Five of 11 adenocarcinomas (45%) and 3 of 14 squamous carcinomas were positive. Survival was similar in AR+ and AR- patients. Studies with established tissue culture cell lines showed AR expression by RT-PCR, with stronger expression of AR in adenocarcinoma lines than in squamous carcinoma lines. The presence of AR in human esophageal cancer is an impetus for further studies to assess anti-androgen therapy for treatment and or prevention of these tumors.

Adenocarcinoma↗
PubMedDate not supplied

Synthetic retinoid CD437 induces apoptosis of esophageal squamous HET-1A cells through the caspase-3-dependent pathway.

6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid (AHPN/CD437) is a novel retinoid that has shown to be a potent inducer of apoptosis in cancer cells. We investigated the apoptosis-inducing activity of CD437 and its mechanism of action in the human esophageal squamous epithelial cell line (HET-1A). CD437 decreased HET-1A cell viability in a time and dose dependent manner. CD437 was found to induce DNA fragmentation. Apoptosis was accompanied by markedly increased activity of caspase-3 as well expression of caspase-3 and -8 and APRP fragmentation. The CD437-mediated activation of caspase-3 was inhibited by Z-DEVD-FMK These data indicate that CD437-induced apoptosis in HET-1A cells may be mediated through the caspase-3 dependent pathway. In addition, apoptosis was also accompanied by increased expression of Bad protein and down-regulation of Bcl-2 expression. Phosphorylation of Jun occurred following CD437 exposure indicating that Jun kinase (JNK) activity was strongly induced by CD437. Understanding these apoptotic pathways of esophageal epithelial cells may allow therapeutic induction of cell death in malignant orpremalignant lesions of the esophagus by agents such as CD437.

Antineoplastic Agents↗
PubMedDate not supplied

New flexible growth function and its application to the growth of small mammals.

The function [formula: see text] where a is the upper asympotic weight and b, c, k are constants, is derived as a new flexible growth equation and evaluated using commonly applied growth functions such as Monomelecular, Gompertz, Logistic, Richards, France, Janoschek and Hill. Three sets of observations on growth of small mammal species (Microtus brandti and Ochotona curzoniae) are used to evaluate the fits of these functions. In addition, points of inflexion of these growth equations are also derived in this paper. The new function encompasses the Logistic and Monomolecular equation for different value of parameter b. It provides a flexible growth equation capable of describing smooth sigmoidal and diminishing returns behaviour. The success of the new equation in describing these sets of growth patterns underlines its credentials as a suitable additional growth function.

Aging↗