An experimental model of the production of early after depolarizations by injury current from an ischemic region

An ischemic myocardial region contains cells with a depolarized resting membrane potential. This depolarization leads to an intercellular current flow between the ischemic region and the surrounding normal myocardial cells which has been termed an injury current. We have devised an experimental model system in which an isolated guinea pig ventricular cell is electrically coupled to a model depolarized cell in order to evaluate the effects of this injury current on the electrical properties of a normal ventricular cell exposed to drugs which increase calcium current or decrease potassium current. Using low doses of isoproterenol, forskolin, or Bay K 8644 (or 8-bromo-cyclic adenosine monophosphate in the pipette) we found that the action potential duration of the isolated cell was lengthened, but that early after depolarizations (EADs) were not produced unless the cell was also coupled to a depolarized cell model representing an adjacent ischemic region. A similar prolongation of the action potential was produced by low doses of quinidine, but EADs were not produced unless coupling to a depolarized cell model was added. EADs could not be produced in any cells in the absence of the drugs even though the coupling to the depolarized cell model was increased up to the level at which the action potential was indefinitely prolonged. At higher isoproterenol concentrations, EADs or spontaneous activity were produced without coupling to the depolarized cell model. Under these conditions, coupling of the cell to a cell model with normal resting membrane potential stopped the spontaneous activity and prevented the occurrence of EADs even with high levels of resistive coupling. These findings suggest that the electrotonic influences of a localized depolarized region can produce EADs if the calcium current magnitude is increased, which would be the case for sympathetic innervation.     

Intraventricular tuberculous abscess: a case report

Ventricles can be involved in different ways in neurotuberculosis, however, the occurrence of intraventricular abscess has been rarely reported. We report a young woman who had intraventricular tubercular abscess. Cranial computed tomographic scan showed hypodense ring enhancing lesion in the right lateral ventricle with unilateral hydrocephalus. She underwent parasagittal craniotomy with total excision of the lesion. The pus obtained from the lesion was teeming with acid fast bacilli.     

Role of caspases in apoptosis and disease.

Apoptosis, a genetically governed process of eliminating cells in response to a variety of stimuli provides protection against cancer and viral infections as well as maintains homeostasis. Recent studies using both molecular and cloning approaches, and in vitro systems have identified a class of highly specific proteases, termed caspases, that appear to have an important role in apoptotic execution. Caspases are synthesized as precursor molecules that require processing at specific aspartate residues to produce the active enzyme which in turn leads to the cleavage of various death substrates that lead to morphological changes typical of apoptosis. This review discusses caspases, their inhibitors and regulators. Since cytotoxic drugs used in chemotherapy of leukemia's and solid tumors cause apoptosis in target cells, elucidating the consequences of proteolytic activity occupies a central role for understanding of the molecular mechanism of apoptosis which can help us to use the caspase inhibitors as targets of therapy.     

Fibrous dysplasia of the mastoid

A rare case of fibrous dysplasia involving the mastoid bone is reported. Its histopathological characteristics are also described.     

Women's health as empowerment: towards a holistic experience

The Women's Health Programme of the nongovernmental organization Social Action for Rural and Tribal Inhabitants of India (SARTHI) serves women living in the Santrampur taluka of Panchmahals district in Gujarat State, India. The program, which has been operating since July 1988, addresses gynecological and psychological health and issues of violence and exploitation. It incorporates traditional health practices and modern allopathic health practices. SARTHI provides gynecologic services via illiterate women health workers (barefoot gynecologists). They also counsel the rural and tribal women and mobilize them for collective action. The 1st phase of the program was training local women in maternal and child health care which included nutrition education and aseptic deliveries. It moved into its 2nd phase due to the realization that it was imposing an external health system on the local women. So the program undertook a research project to verify locally used traditional medicines. Training of the barefoot gynecologists marked the beginning of the 3rd phase. These women health workers soon realized that their main objective was empowerment of the local women. The program provides women with information to empower them to deal with their problems. Training is the key to the program's success. it designed training in phases to build upon knowledge. It begins with an 8-day training program followed by 3-day modules each month. Training includes technical health information and empowerment and leadership building. Content depends on the current situation of the women. Methodologies include role playing, songs, question-answer sessions, and reviews.     

Factors involved in the differential response to ethanol,barbital and pentobarbital in rats selectively bred for ethanol sensitivity

Two lines of rats, least affected (LA) and most affected (MA), had been selectively bred for their differential sensitivity to ethanol. Both males and females of the LA strain were observed to be less sensitive than their MA counterparts to the acute hypnotic and motor-impairing effects of ethanol. However, a lower ethanol metabolic rate of the MA males suggests that both CNS and metabolic factors contribute to their enhanced sensitivity to ethanol. By contrast, no differences were observed between the LA and MA males with respect to the hypnotic and subhypnotic effects of pentobarbital or to the clearance of this drug. MA females were more sensitive only to the hypnotic effects of pentobarbital, probably because of a smaller apparent volume of distribution. No strain difference was observed in the hypnotic effect or clearance of barbital. These observations suggest that, in spite of a differential sensitivity to ethanol, the LA and MA lines do not differ in their response to the barbiturates tested.     

Sarcomas of the breast: Homogenous or heterogenous?

Eighteen cases of sarcomas of the breast are reported. Cases could be divided into two groups histogenetically. Group A, malignant cystosarcoma phylloides (14 cases); and Group B, pure sarcomas (4 cases). The malignant cystosarcoma phylloides occurred in the forth decade, had linger duration of illness invariably followed by sudden increase in the size of the tumor, had a striking mucoid and slimy look grossly, and showed discernible epithelial elements histologically. In the event of their recurrence the ductal elements were not seen microscopically. Contrarily, Group B cases presented in the sixth decade were rapidly growing from the beginning, and grossly were fleshy and haemorrhagic. Microscopically these did not reveal any epithelial component. There was poor correlation between cytologic malignancy and the biologic behavior in Group A. Mode of treatment seems more important in determining the subsequent course of the disease. Simple mastectomy with follow-up appears to be adequate in the majority of cases.