Results from this study suggest that hyperhomocysteinemia-induced hypertension and ventricular hypertrophy in rats are mediated, at least partly; by Ang II activation of AT1-receptors.

Abstract:We have previously evaluated veratridine as an in vitro model of seizure using conventional electrophysiological recordings in rat hippocampal CA1 pyramidal neurones. The aim of this investigation is to further characterize this convulsant as an in vivo model of seizure. Veratridine was administered intraperitoneally to male Fisher rats in a dose range of 100-400 mg/kg. Within 5 min. after the injections, the animals entered a quiescent period which was followed 10-15 min. later by facial automatism (washing), grooming, masticatory jaw movement and profuse salivation. This phenomenon was followed by the development of wet dog shake and forelimb clonus. The time (mean∫S.E.M.) for the onset of induction of these shakes for all tested doses was 31.65∫2.85 min. and the number of shakes (mean∫S.E.M.) 30 min. after the onset was 17.2∫2.85. The onset and number of wet dog shakes induced by veratridine was dose-dependent. No rat death was recorded until 2 weeks after the experiments. Histopathological studies of animals 2 weeks after veratridine administration showed evidence of apoptosis in the hippocampus. Our results indicate that veratridine produced a behavioural pattern of a limbic seizure which mimics temporal lobe epilepsy in man. Based on our previous findings in vitro and of this investigation in vivo, veratridine can be used as an experimental tool to evaluate potential antiepileptic drugs effective against this type of limbic behaviour.We have characterized the proconvulsant activity of veratridine in vitro in rat brain slices and conventional electrophysiological intracellular techniques in hippocampal CA1 pyramidal neurones (Tian et al. 1995). Veratridine (0.03-0.2 mM) caused no changes in the passive membrane parameters including the resting membrane potential and input resistance. These concentrations also induced a relatively slow, large, synaptic-independent potential called the slow depolarizing after-potential. Higher doses of veratridine (over 0.1 mM) induced bursting, or seizure-like activity after applying a brief super threshold intracellular stimulation (Tian et al. 1995). The duration of seizure-like activity bursting which can be up to 10 sec. was dependent on the amplitude of slow depolarizing after-potential, and not on the stimulus strength or duration. At 0.3 mM or higher concentration, veratridine induced spontaneous rhythmic bursting. Both veratridine-induced evoked or spontaneous rhythmic bursting were sensitive to membrane potential changes and independent of synaptic transmission (Otoom et al. 1998). This was evident when seizure activity persisted after complete blockade of evoked synaptic potential with kynurenic acid.The mechanism of veratridine-induced bursting activity in hippocampal CA1 pyramidal neurones revealed that veratridine accentuated the depolarizing rectification so that a

Our study revealed substantial reduction in the protein expression profile of THRs in malignant versus nonmalignant mammary epithelium suggesting a possible role in breast cancer development. The presence of THRs in mammary epithelium seems to be protective against the development of breast cancer. This could serve as a potential prognostic and therapeutic target for breast cancer.

The sensitivity and specificity of different staining procedures for the detection of Pneumocystis carinii organisms were compared. Three conventional stains (Papanicolaou, Giemsa and Grocott's) and one immunocytochemical stain using 3F6 antibody were used on smears prepared from the same specimen. Bronchoalveolar lavage (BAL) and induced sputum (IS) specimens were used for this purpose. One hundred and sixty-five episodes from 142 patients were investigated by the four different staining techniques. Cysts of P. carinii were detected in 64 episodes from 63 patients. Immunocytochemical staining with 3F6 was found to be slightly more sensitive at detecting the cysts than Grocott's, Giemsa, or Papanicolaou stain.

The role of estrogen and progesterone receptors in breast cancer biology is well established. In contrast, other steroid hormones are less well studied. Glucocorticoids (GCs) are known to play a role in mammary development and differentiation; thus, it is of interest to attempt to delineate their immunoexpression across a spectrum of mammary epithelia. Aim. To delineate the distribution pattern of glucocorticoid receptors (GRs) in malignant versus nonmalignant epithelium with particular emphasis on lactational epithelium. Materials and Methods. Immunohistochemistry (IHC) for GRs was performed on archival formalin-fixed paraffin-embedded tissue blocks of 96 cases comprising 52 invasive carcinomas, 21 cases with lactational change, and 23 cases showing normal mammary tissue histology. Results. Results reveal an overexpression of GRs in mammary malignant epithelium as compared to both normal and lactational groups individually and combined. GR overexpression is significantly more pronounced in HER-2-negative cancers. Discussion. This is the first study to compare GR expression in human lactating epithelium versus malignant and normal epithelium. The article discusses the literature related to the pathobiology of GCs in the breast with special emphasis on breast cancer. Conclusion. The lactational epithelium did not show overexpression of GR, while GR was overexpressed in mammary NST (ductal) carcinoma, particularly HER-2-negative cancers.