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Biomedical subjects

T Lahiri

Publications and source records attributed to T Lahiri.

7 recordsLinked to original sources
PubMed1992

Alteration of brain catecholamines during growth of benzo(a)pyrene induced murine fibrosarcoma.

Brain catecholamines (CA) were studied in discrete brain areas of benzo(a)pyrene (b(a)p) induced fibrosarcoma bearing mice. Dopamine (DA) and norepinephrine (NE) levels decreased significantly in different brain areas especially in corpus striatum and hypothalamus with the tumor progression, indicating an inverse relationship between brain DA and NE levels and tumor growth. Since impaired hormonal and immunological functions are manifestation of systemic alteration during tumor growth, it appears that during malignant growth an alteration of these brain CA may play an important role in the regulation of systemic alterations.

Animals↗
PubMed1991

Decrease in dopamine and norepinephrine concentration in different brain regions of mice during progression of Sarcoma 180 tumour.

The distribution and concentration of dopamine (DA) and norepinephrine (NE), the catecholamine neurotransmitters, were studied in discrete brain areas of Sarcoma 180 tumour bearing mice. With the progression of tumour, marked depletion of DA and NE concentration was observed in some brain areas richly innervated with dopaminergic and noradrenergic neurons suggesting an inverse relationship between brain CA and tumour growth. Since brain CA influence different important physiological activities like hormonal and immunological functions, it's alteration in brain areas during malignant growth suggests the possibility that the hormonal and immunological alterations during tumour growth is at the level of brain CA.

Animals↗
PubMed1990

Tumor inhibition and hematological improvements by dopamine analog 3,4-dihydroxybenzylamine in mice bearing transplantable carcinoma.

The cancer chemotherapeutic efficacy of 3,4-dihydroxybenzylamine (DHBA), a dopamine analog with reduced neurotoxic effects, was evaluated in strain A mice bearing transplantable Ehrlich's ascites carcinoma. The analog was administered intraperitoneally on day 1 post-transplantation at dose schedules of 50, 100 and 200 mg/kg/day for 7 consecutive days. The results demonstrated a significant inhibition of tumor growth and prolongation of the survival time of EAC tumor bearing mice following DHBA treatment. Diminished activity of the growth-related respiratory enzyme succinate dehydrogenase along with the stimulated activity of the lysosomal enzyme beta-glucuronidase in the DHBA-treated tumor cells indicated inhibition of tumor growth as well as active lysis of the tumor cells. Tumor inhibition was accompanied by marked improvements in hemoglobin concentration. RBC count and bone marrow cellularity. The results demonstrated that DHBA did not adversely affect hematological profile of the host while it inhibited the growth of Ehrlich's ascites carcinoma.

Animals↗
PubMed1988

Single and fractionated whole body hyperthermia in murine fibrosarcoma.

The effects of single and multiple fractionated whole body hyperthermia (WBH) 41.5 degrees C on benzo(a) pyrene induced fibrosarcoma of mice were evaluated in terms of tumour response and systemic alterations of the host. While single exposure of WBH(S) 2 hrs, caused moderate inhibition of tumours and increase in the median survival time, multiple fractionated exposures [WBH(M)] caused significant enhancement of tumours with decrease in mean survival time. Tumoricidal effects associated with increased acid phosphatase and beta-glucuronidase activity were observed in both the regimes of WBH. In WBH(M) the development of thermotolerance was indicated by decreased activity of these enzymes in subsequent treatments. Elevation of plasma corticosterone and significant lymphocytopenia occurred in both the regimes. The alterations were transient in WBH(S) but persisted for more than two weeks in WBH(M), indicating that tumour enhancement is possibly influenced by corticosterone-mediated immunosuppression. In the WBH(M), the tumoricidal effects were counteracted and surpassed by the growth stimulatory physiological alterations of the host. Therefore the mode of application of WBH and the systemic responses of the host are critical factors that should be considered in designing therapeutic regimes with WBH.

Acid Phosphatase↗
PubMed1987

Variability in response pattern of DMBA induced mammary tumors of Wistar rats.

The incidence and growth pattern of DMBA induced mammary tumors of Wistar rats in altered hormonal conditions induced by endocrine ablation were studied. Elevation of prolactin by pituitary stalk section, removal of primary source of estrogen by bilateral oophorectomy or both were done before administration of DMBA as well as after formation of palpable tumors. The results indicate that while estrogen is essential for the induction of these tumors, elevation of prolactin before administration of DMBA inhibits tumor incidence. From the overall responses (mean tumor volume) in the different groups it is evident that prolactin alone cannot maintain growth of these tumors, estrogen is also essential at least in a large percentage of tumors. The marked intertumor and intratumor differences in the response pattern to altered hormonal situations demonstrate close resemblances of this tumor model to the human breast cancer.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1986

Tumor growth enhancement and systemic responses of Ehrlich ascites carcinoma following intermittent whole body hyperthermia.

Intermittent whole body hyperthermia 42 degrees C (WBH(I) administered for 30 min daily during 7 days caused significant enhancement of the growth of Ehrlich ascites carcinoma. The tumoricidal effects of hyperthermia were evident from the cytological picture as well as from the increased activity of lysosomal enzyme of the tumor cells. Elevated plasma corticosteroid levels, adrenal hypertrophy, thymus involution and lymphocytopenia were observed in both normal and tumor bearing mice exposed to hyperthermia. The alterations were more marked in the tumor bearing groups. Withdrawal of treatment caused gradual restoration of stress effects. It appears that the tumoricidal effects of WBH(I) were counteracted and surpassed by the growth stimulatory effects induced probably by hormone mediated immunosuppression.

Adrenal Glands↗