Formulation development and in vitro evaluation of gastroretentive hollow microspheres of famotidine.

Background: The main aim of this study was to develop a gastroretentive, multiple-unit floating drug delivery system for a drug which is poorly absorbed from the lower gastrointestinal tract. Such a dosage form may provide an extended retention of drug in the upper gastrointestinal tract resulting in enhanced absorption and improved bioavailability.

Materials And Methods: Microspheres were prepared by the emulsion solvent diffusion method.

Human sperm immobilization effect of Carica papaya seed extracts: an in vitro study.

Aim: To examine if the seed extracts of Carica papaya, which showed antispermatogenic/sperm immobilization properties in animal models, could cause human sperm immobilization in vitro.

Methods: Chloroform extract, benzene chromatographic fraction of the chloroform extract, its methanol and ethyl acetate sub-fractions and the isolated compounds from the sub-fractions i.e.

Technetium-99m-cyclam AK 2123: a novel marker for tumor hypoxia.

Technetium-99m labeled cyclam N-2'-methoxyethyl-2-(3'-nitro-1'-triazole) acetamide (cyclam AK 2123) has been synthesized, radiolabeled and characterized as a hypoxic tumor imaging agent. Radiochemical purity was greater than 95%. Marker biodistribution was measured in normal Wistar strain rats at different time intervals after intra venous (i.

Effects of melatonin on mammary gland lesions in transgenic mice overexpressing N-ras proto-oncogene.

The oncostatic effects of melatonin on the mammary gland have been studied in transgenic mice carrying the N-ras proto-oncogene under the control of the MMTV-LTR. Female (4-week-old) virgin mice with positive transgenic pedigrees were injected with melatonin (200 micrograms/mouse/ day, five times a week) or vehicle late in the evening. After 5 months of treatment, animals were sacrificed and the mammary glands were dissected for whole mounts, histology, and immunohistochemical analysis with a mouse monoclonal antibody specific for N-ras protein.

Combination of melatonin and tamoxifen as a chemoprophylaxis against N-nitroso-N-methylurea-induced rat mammary tumors.

The effect of melatonin (Mel) and or tamoxifen (Tam) was evaluated on a mammary tumor model induced in 50 day old female Sprague-Dawley rats by a single intraperitoneal (i.p.) injection of a direct carcinogen, N-nitroso-N-methylurea (NMU) (50 mg/kg b.

Chemoprevention by melatonin and combined melatonin-tamoxifen therapy of second generation nitroso-methylurea-induced mammary tumours in rats.

Melatonin, an indole of pineal origin, is known to have an oncostatic effect on carcinogen-induced rat mammary tumours. We have assessed for the first time, the efficacy of melatonin alone and in combination with a sub-optimal dose of tamoxifen, a partial oestrogen antagonist, on N-nitroso-N-methylurea-induced rat mammary tumours. Both these agents were administered to Sprague-Dawley rats following excision of the primary tumours.

Cancer immunotherapy with low-dose interleukin-2 subcutaneous administration: potential efficacy in most solid tumor histotypes by a concomitant treatment with the pineal hormone melatonin.

The antitumor efficacy of IL-2 is limited to renal cancer and melanoma. Several cytokines have been associated with IL-2 in an attempt to improve its activity, without, however, any clear benefit. Recent experimental and clinical studies have suggested the possibility to manipulate the host biological response by immunomodulating neurohormones, such as the pineal hormone melatonin (MLT).

A possible modulatory influence of melatonin on representative phase I and II drug metabolizing enzymes in 9,10-dimethyl-1,2-benzanthracene induced rat mammary tumorigenesis.

The oncosuppressive effect of melatonin on 9,10-dimethyl-1,2-benzanthracene (DMBA) induced rat mammary tumorigenesis led us to assess its possible modulatory influence on representative hepatic and mammary drug metabolizing enzymes in DMBA treated female Holtzman rats, reared in short and long photoperiods. Melatonin treated rats in either photoperiod showed a significant induction in hepatic and mammary levels of glutathione (GSH) and cytosolic activities of glutathione S-transferase (GST) when compared with the corresponding controls, along with a significant drop in hepatic microsomal contents of cytochromes b5 and P450. This induction of GSH and GST, and depletion of cytochromes b5 and P450 by melatonin may possibly be related to its anticarcinogenic potential in this tumor model.

Effect of neonatal pineal ablation on estradiol receptors in mammary glands of rats housed under varying photoperiods.

Estradiol receptors (ER) in mammary glands of female Holtzman rats, either intact or neonatally pinealectomised and housed in 10:14 or 24:0 L:D (light:dark) schedule were studied at 30, 40, 50 +/- 5 and 65 +/- 5 days of age. Whereas ER were detectable only at the age of 60-65 days in intact rats housed in 10:14 L:D, they were present as early as 30 days onwards in the pineal ablated group. In the 24:0 L:D pinealectomised group, though mammary gland ER were maximum around 40 days of age and temporarily undetectable around day 50, they had stabilized around the age of 60-65 days.

Suppressive effect by melatonin on different phases of 9,10-dimethyl-1,2-benzanthracene (DMBA)-induced rat mammary gland carcinogenesis.

This comprehensive study examines the influence of oral melatonin on the initiation and promotion phases of DMBA-induced mammary tumorigenesis in intact and pinealectomized female Holtzman rats reared in short (light:dark schedule L:D 10:14) and long (L:D 24:0) photoperiods. Melatonin administration in the initiation phase significantly suppressed tumor incidence only in intact animals reared in both photoperiods, indicating that the presence of the pineal was obligatory. On the other hand, during the promotion phase, irrespective of the presence or absence of the pineal, the tumor-suppressive effect of exogenous melatonin was pronounced.

Melatonin, a suppressor of spontaneous murine mammary tumors.

The effect of prolonged, oral melatonin treatment on spontaneous mammary tumor development in female C3H/Jax mice was studied. Melatonin was administered at a dose of 25 micrograms/mouse/day from 21 to 44 days of age and 50 micrograms/mouse/day from day 45 onwards. By the age of 12 months, 62.

Effect of vitamin C deficiency and excess on the liver: a histopathological and biochemical study in guinea pigs fed normal or high cholesterol diet.

When guinea pigs were kept on a restricted vitamin C intake of only 0.5 mg daily, their serum ascorbic acid fell to 0.16 +/- 0.

Indian contribution to reproductive physiology: the last 2 decades.

The end of twentieth century is witnessing far-reaching changes in the reproductive behaviour of modern man. Population is doubling now in a record time of 30 years in some parts of the world like India. On the other hand, living-together without marriage and widespread use of contraceptives is making child bearing highly optional in the West.

Leucocyte and serum ascorbic acid levels in mothers and their newborn in semi-arid western India.

Leucocyte ascorbic acid (LAA) and serum ascorbic acid (SAA) have been estimated in 50 pregnant women, their newborn infants, and 14 non-pregnant women living in the semi-arid region of western India. LAA was significantly higher in the newborn as compared to their mothers, the mean values being 35.52 +/- 6.

Aggravation of cholesterol induced hyperlipidemia by chronic vitamin C deficiency: experimental study in guinea pigs.

Chronic vitamin C deficiency was induced in guinea pigs by restricting their vitamin C intake to 0.5 mg daily. This was just sufficient to prevent rapidly fatal scurvy and 55 per cent of the animals survived.

Influence of chronic melatonin on 9,10-dimethyl-1,2-benzanthracene-induced mammary tumors in female Holtzman rats exposed to continuous light.

Daily treatment of 'functionally' and surgically pinealectomized female Holtzman rats reared in continuous light (light:dark schedule, 24L:OD) with oral melatonin (100 micrograms/day/rat) initiated 30 days prior to and 90 days following 9,10-dimethyl-1,2-benzanthracene (DMBA) administration on day 55 of age, resulted in a highly significant suppression of mammary tumor incidence and prolongation of latency period of tumor appearance (p less than 0.001). An identical treatment schedule of melatonin to intact rats given DMBA, housed in short photoperiods (10L:14D), also resulted in a significant suppression of tumor incidence (p less than 0.

Structural organisation within the epididymis and its functional implications.

The functional organisation of the epididymis has been studied in 20 adult albino rats. The gross divisions of Caput or head, Corpus or body, and Cauda or lower end show distinctive features which indicate functional specialisation. The Caput epididymis has strikingly tall columnar cells with a mean height of 124 mu, but little muscle tissue.

Effect of melatonin on mammary carcinogenesis in intact and pinealectomized rats in varying photoperiods.

Exposure of female Holtzman rats to constant light (24 hr/day) immediately after birth significantly increased 9, 10-dimethyl-1,2-benzanthracene-induced mammary cancer. Such "functionally pinealectomized" animals also revealed significant increase in the circulating level of prolactin and exaggerated development and proliferative activity of mammary epithelium, as measured by quantitation of terminal end buds and alveolar buds from the whole mounts and by DNA synthesis, respectively. Administration of melatonin (500 micrograms/day/rat i.

Pineal ablation in varying photoperiods and the incidence of 9,10-dimethyl-1,2-benzanthracene induced mammary cancer in rats.

Our earlier observation of increased incidence of 9,10-dimethyl-1,2-benzanthracene (DMBA) induced mammary carcinoma in young, virgin 'functionally' pinealectomized Holtzman rats poses the question whether or not a comparable incidence would occur in surgically pinealectomized rats reared in varying photoperiods (e.g. light/dark (LD) 24/0 or LD 10/14 schedules).

Effect of continuous light on the incidence of 9,10-dimethyl-1,2-benzanthracene induced mammary tumors in female Holtzman rats.

The pineal has been recently implicated in mammary tumorigenesis. Effect of physiological pinealectomy brought about by subjecting female Holtzman rats to permanent lighting (24 h/day) from birth was studied on the incidence of 9,10-dimethyl-1,2-benzanthracene (DMBA) induced mammary tumors. The incidence of adenocarcinoma was 95% in animals maintained in continuous photoperiod in contrast to that (60%) observed in control animals maintained on a light/dark (10/14 h) schedule.