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Biomedical subjects

V Go

Publications and source records attributed to V Go.

10 recordsLinked to original sources
PubMed2003

The prototypic antidepressant drug, imipramine, but not Hypericum perforatum (St. John's Wort), reduces HPA-axis function in the rat.

Dysregulation in corticotropin-releasing hormone (CRH) secretion in the hypothalamus-pituitary-adrenal (HPA) axis may be involved in the etiology of major depressive disorder (MDD). Chronic therapy with standard antidepressant drugs, such as imipramine, can downregulate HPA axis function, indicating that the HPA axis may be an important target for antidepressant action. We tested several doses of a standardized commercial preparation of Hypericum perforatum plant extract (popularly known as St. John's Wort), a medicinal herb used for treating mild depressive symptoms, to determine whether it also modulated HPA axis function. Chronic imipramine treatment (daily injections for 8 weeks) of male Sprague-Dawley rats significantly downregulated circulating plasma levels of adrenocorticotropic hormone (ACTH) and corticosterone compared to animals treated with saline. However, chronic St. John's Wort treatment (daily gavage for 8 weeks) had no effect on plasma ACTH or corticosterone, even at the highest doses tested. Our results confirm previous findings that imipramine may have significant peripheral HPA axis-mediated effects. However, our data does not support any role for H. perforatum in modulation of HPA axis function, suggesting that alternative pathways may be involved in mediating its antidepressant effects.

Adrenal Glands↗
PubMed2001

MMTV-like env gene sequences in human breast cancer.

We have previously detected an MMTV env gene-like 660 bp sequence in 38% of human breast cancers, but not in normal tissues or other tumors. In this communication we report the sequences from eleven tumors and three breast cancer cell lines, and compare them to four strains of MMTV and to the known endogenous retroviral sequences. The breast cancer sequences were highly homogenous to the MMTV's, but not to the endogenous sequences suggesting an exogenous origin.

Animals↗
PubMed1999

Estrogenic potential of certain pyrethroid compounds in the MCF-7 human breast carcinoma cell line.

Estrogens, whether natural or synthetic, clearly influence reproductive development, senescence, and carcinogenesis. Pyrethroid insecticides are now the most widely used agents for indoor pest control, providing potential for human exposure. Using the MCF-7 human breast carcinoma cell line, we studied the estrogenic potential of several synthetic pyrethroid compounds in vitro using pS2 mRNA levels as the end point. We tested sumithrin, fenvalerate, d-trans allethrin, and permethrin. Nanomolar concentrations of either sumithrin or fenvalerate were sufficient to increase pS2 expression slightly above basal levels. At micromolar concentrations, these two pyrethroid compounds induced pS2 expression to levels comparable to those elicited by 10 nM 17ss-estradiol (fivefold). The estrogenic activity of sumithrin was abolished with co-treatment with an antiestrogen (ICI 164,384), whereas estrogenic activity of fenvalerate was not significantly diminished with antiestrogen co-treatment. In addition, both sumithrin and fenvalerate were able to induce cell proliferation of MCF-7 cells in a dose-response fashion. Neither permethrin nor d-trans allethrin affected pS2 expression. Permethrin had a noticeable effect on cell proliferation at 100 microM, whereas d-trans allethrin slightly induced MCF-7 cell proliferation at 10 microM, but was toxic at higher concentrations. Overall, our studies imply that each pyrethroid compound is unique in its ability to influence several cellular pathways. These findings suggest that pyrethroids should be considered to be hormone disruptors, and their potential to affect endocrine function in humans and wildlife should be investigated.

Breast Neoplasms↗
PubMed1998

Expression of mouse mammary tumor virus-like env gene sequences in human breast cancer.

We have reported previously (Wang et al, Cancer Res., 55: 5173-5179, 1995) the presence of a 660-bp sequence that is 90-98% homologous to the env gene of mouse mammary tumor virus in 38% of 314 unselected breast cancer samples, in some breast cancer cell lines, and in 1.8% of the 107 normal breast specimens from reduction mammoplasties. In this communication, we have investigated whether the 660-bp sequence or a smaller 256-bp sequence within the 660 bp were expressed in breast tumors, normal breasts, and breast cancer cell lines by means of reverse transcription-PCR. The results indicated that expression of the 660-bp sequence was detected in 66% of the sequence-positive breast tumors studied and in none of the negative tumors or normal breasts and that the 256-bp sequence was expressed in all of the env-positive breast cancer cell lines tested. Sequence analysis revealed that the expressed 660-bp sequence is 98% homologous to the env gene of mouse mammary tumor virus with only one small stretch of 46 bp homologous to endogenous viral sequences. The presence and expression of this sequence is related to a group of human breast cancers in which the concept of a retroviral etiology can be entertained.

Animals↗
PubMed1997

Widely varying HIV prevalence and risk behaviours among the ethnic minority peoples of northern Thailand.

We compared HIV prevalence, risk behaviours, and social and sexual norms among nine ethnic minority (Hilltribe) groups in northern Thailand. Communities were selected on the basis of size, ethnicity, development level and geography. Subjects (15-45 years) were stratified by gender and selected by household using two-stage randomization. Forty volunteers were identified in each of 27 villages. Participation was voluntary and informed consent was obtained. HIV infection status was determined using ELISA and Western Blot on saliva samples. Risks for HIV were measured with structured interviews using local languages. Overall HIV prevalence was 23/1080 (2.13%) with an equal male-female ratio. HIV prevalence rates were: Shan 8.75%, Akha 5.0%, Yao 5.0%, Thin 1.25%, Hmong 0.63%, Lahu 0.63%, Lisu 0.63%, Karen 0, and Pa-Long 0. Sex worker use was an HIV risk for men (p = 0.0001), but injecting drug use was not; for women, having been a sex worker was a significant HIV risk (p < 0.0001). HIV rates, social norms and sexual behaviour varied considerably among ethnic groups, as did attitudes toward commercial sex work and use. HIV prevention needs to target the Shan, Akha, and Yao communities, and to focus on reduction of brothel work and use.

Adolescent↗
PubMed1997

[Searching for retroviral sequences related to human breast cancer].

The participation of viruses in mammary carcinogenesis has been largely studied in animals. A model similar to the mouse mammary tumor virus (MMTV) was previously proposed. Several lines of research supported the participation of MMTV in human breast cancer, but these evidences were contradicted when further research was performed. One major issue was the presence of human endogenous retroviral sequences that confounded results reporting MMTV-like sequences in human breast cancer. To overcome this problem we selected a 660 bp sequence of the MMTV env gene with low homology to endogenous sequences and search for a sequence to it using the polymerase chain reaction (PCR). The sequence was found in 38% of the human breast cancers and in 2% of the normal breasts studied. The sequence was not present in tumors from other organs. It was 90-98% homologous to MMTV and only 18% to human endogenous retrovirus (HERV) K-10. It was also detected in some of the positive tumors by Southern blot hybridization using one of the cloned 660 bp as a probe. Using reverse transcriptase PCR, it was possible to demonstrate that the 660 bp sequence is expressed in the majority of the tumors. Also, preliminary experiments revealed that sequences related to the LTR and gag genes of MMTV were present in the DNA of breast tumors. The origin of the MMTV-like sequences in tumor DNA could be the result of integrated MMTV-like sequences derived from a human mammary virus or may represent unknown endogenous sequences that can only be detected in breast tumors.

Animals↗
PubMed1995

Health problems of Maryland's migrant farm laborers.

The health problems of Maryland's agricultural migrant labor force are presented for the information of Maryland's health care providers. Maryland's problems are placed in the context of U.S. and worldwide migrant labor practices.

Adolescent↗
PubMed1982

Effects of the disaccharidase inhibitor acarbose on meal and intravenous glucose tolerance in normal man.

To determine whether the effects of the disaccharidase inhibitor Acarbose on glucose tolerance could be solely explained via an action on intestinal nutrient absorption, the effects of this agent and placebo (100 mg p.o.) on intravenous and postprandial glucose tolerance were compared in six normal subjects. Acarbose significantly diminished plasma glucose, insulin, and gastrointestinal inhibitory polypeptide responses following meal ingestion without affecting plasma glucagon and pancreatic polypeptide responses, but had no effect on plasma glucose and insulin responses following intravenous injection of glucose. These results suggest that the acute effects of Acarbose on glucose tolerance can be explained on the basis of its ability to alter intestinal nutrient absorption.

Acarbose↗
PubMed1982

Stimulation of human pancreatic polypeptide secretion by hypoglycemia is independent of adrenergic mechanisms.

Human pancreatic polypeptide (HPP) increases after insulin-induced hypoglycemia. To determine whether adrenergic mechanisms contribute to this increase in normal man, six subjects were studied on two occasions: once after insulin alone and once after insulin plus simultaneous alpha (phentolamine)- and beta (propranolol)-adrenergic blockade. Despite comparable hypoglycemia (51 +/- 4 vs. 49 +/- 4 mg/dl), the increase in HPP did not differ in the presence or absence of adrenergic blockade (721 +/- 215 vs. 736 +/- 193 pg/ml, respectively). These findings suggest that HPP secretion during hypoglycemia is not dependent on adrenergic mechanisms.

Adult↗