Structural basis of the strong cell-cell junction formed by cadherin-23.

Cadherin-23, a giant atypical cadherin, forms homophilic interactions at the cell-cell junction of epithelial cells and heterophilic interactions with protocadherin-15 at the tip-links of neuroepithelial cells. While the molecular structure of the heterodimer is solved, the homodimer structure is yet to be resolved. The homodimers play an essential role in cell-cell adhesion as the downregulation of cadherin-23 in cancers loosen the intercellular junction resulting in faster-migration of cancer cells and a significant drop in patient survival. In vitro studies have measured a stronger aggregation-propensity of cadherin-23 compared to typical E-cadherin. Here, we deciphered the unique trans-homodimer structure of cadherin-23 in solution, and show that it consists of two electrostatic-based interfaces extended up to two terminal domains. The interface is robust, with a low off-rate of ~8x10-4 s-1 that supports its strong aggregation-propensity. We identified a point-mutation, E78K, that disrupts this binding. Interestingly, a mutation at the interface was reported in skin cancer. Overall, the structural basis of the strong cadherin-23 adhesion may have far-reaching applications in the fields of mechanobiology and cancer.

Symmetry and the geometric phase in ultracold hydrogen-exchange reactions.

Quantum reactive scattering calculations are reported for the ultracold hydrogen-exchange reaction and its non-reactive atom-exchange isotopic counterparts, proceeding from excited rotational states. It is shown that while the geometric phase (GP) does not necessarily control the reaction to all final states, one can always find final states where it does. For the isotopic counterpart reactions, these states can be used to make a measurement of the GP effect by separately measuring the even and odd symmetry contributions, which experimentally requires nuclear-spin final-state resolution. This follows from symmetry considerations that make the even and odd identical-particle exchange symmetry wavefunctions which include the GP locally equivalent to the opposite symmetry wavefunctions which do not. It is shown how this equivalence can be used to define a constant which quantifies the GP effect and can be obtained solely from experimentally observable rates. This equivalence reflects the important role that discrete symmetries play in ultracold chemistry and highlights the key role that ultracold reactions can play in understanding fundamental aspects of chemical reactivity more generally.

Spontaneous nonmetastatic choriocarcinoma, yolk sac carcinoma, embryonal carcinoma, and teratoma in the testes of a swiss albino mouse.

A 12-week-old Swiss Albino mouse was presented with unilateral (left) testicular enlargement of approximately 1.5 cm in diameter and the right testicle mildly reduced in size and weight. Histopathology evaluation revealed three distinct neoplasms in the left testicle: choriocarcinoma, yolk sac carcinoma, and embryonal carcinoma. Teratoma was diagnosed in the right testicle. The histomorphological and immunohistochemical characteristics of the tumor are presented here. To the best of the authors' knowledge, this is the first report of spontaneous nonmetastasizing choriocarcinoma, yolk sac carcinoma, embryonal carcinoma, and teratoma in testes of a Swiss albino mouse.

A spontaneous teratocarcinoma in the testis of a swiss albino mouse.

A unilateral non-metastatic embryonal carcinoma and teratoma of the testis was observed in a 12-week-old Swiss Albino mouse at the end of a 28-day repeated dose toxicity study. The teratocarcinoma almost completely replaced the parenchyma of the left testis. The tumor was composed of sheets and rosettes of primitive embryonal cells, anaplastic cells, skeletal muscle tissue, sebaceous gland tissue, keratinized stratified squamous epithelium, and ciliated cuboidal epithelium. The histomorphological characteristics of the tumor were reviewed and presented in this report. To the best of the authors' knowledge, this is the first report of spontaneous teratocarcinoma of testis in the Swiss Albino strain of mice.

Manipulating higher partial-wave atom-atom interactions by strong photoassociative coupling.

We show that it is possible to change not only s-wave but also higher partial-wave atom-atom interactions in a cold collision in the presence of relatively intense laser fields tuned near a photoassociative transition.

Arsenic induced toxicity on testicular tissue of mice.

Effect of arsenic was studied on the testicular tissue of Swiss albino mice. Sodium-meta-arsenite (NaAsO2) was administered to adult mice (25 +/- 30 g) at a dose level of 30 mg/L and 40 mg/L through drinking water for 30, 45 and 60 days. After the treatment, the testicular organ was removed, weighed and processed for histopathological observation. No change in the body weight was recorded in treated groups after arsenic exposure but significant decrease in the relative testicular weight was observed in comparison with the control. The result showed that arsenic-treated mice exhibited dose dependent gradual reductions in seminiferous tubular diameter and various gametogenic cell population i.e. resting spermatocyte, pachytene spermatocyte and step-7-spermatid except spermatogonia. Leydig cell atrophy was significantly increased in dose dependent manner indicating a definite effect of arsenic on the spermatogenesis in mice. These observations were supported by gradual reduction in Leydig cell population in the above treated groups. In conclusion, the above results confirm the toxic effect of arsenic in testis of mice.

Tea (camelia thea): boon or curse for human being.

Drinking some types of tea and other caffaeinated drink is a part of our culture and everyday life. It is contained from the leaves and seeds of evergreen plant (Camelia thea). It is caffeine contained in so many drinks which really plays havoc with our body and mind. It is only when man exceeds they tea drinking that he experiences the ill effects. When taken in limited quantity tea is indeed very good for health.

Epidemiology of peptic ulcer in north Bengal, India.

A retrospective analysis of hospital records of inpatients of Medicine department of North Bengal Medical College and Hospital during the period between 1988-90 revealed that 6.2% of all medical admissions were on account of peptic ulcer and or acute gastritis. Duodenal ulcer was prevalent accounting for more than 50% of the cases of peptic ulcer and acute gastritis. Duodenal ulcer was more common in the working age groups (> 21 years) among males and more than 31 yrs among females. Gastric ulcer was more common among older age groups. In respect to ethnicity, Bengali speaking hindus showed high probability for gastric ulcers in both sexes. The probability for duodenal ulcer was within confidence limits among all social groups.

Tuberculosis in West Bengal.

Inspite of the various curative and preventive measures the control of tuberculosis has not been effective. Today it persists as an endemic disease in many parts of India. The present study aims to map the spatial distribution of tuberculosis in West Bengal and to evaluate the spatial change over time between 1960 to 1980. The mortality data for the 16 districts of West Bengal have been used to map spatial distribution of tuberculosis for 1980 and the expected deaths have been calculated based on the mid-year population. The rural and urban sectors have been treated separately. Similarly a time space change in tuberculosis mortality has been calculated for the districts based on the quinquinneal population change between 1960, 1965, 1970, and 1980. In all cases the probability has been tested by Poissons Probability model at the significance levels of p less than 0.01 and p less than 0.05. The principal zones of tuberculosis endemicity are the Nn.Hill region and the adjoining plains, the central plains of Bankura district, and Calcutta. A wide rural urban difference is perceptible in spatial context as well as in time scale. Though tuberculosis is principally a disease of the male population, it is more prevalent among females of the lower age group. The declining trend of tuberculosis though observable from 1965 is not uniform for all districts. An increasing trend in Purulia is apparent in the present decade while in Calcutta the trend of decline is very gradual.

In vitro demonstration of seasonal transition effect on acetylcholine liberation from Auerbach's plexus of non-hibernator.

Acetylcholine release from Auerbach's plexus of guinea-pig ileum, in vitro, both spontaneous and evoked by field-stimulation, responds to the seasonal transition from the spring to close to the beginning of summer. It did not change during the summer, however, tended to be higher than during the initial period (3 weeks after the beginning of spring).

Evidence against prostaglandin E having a physiological role in acetylcholine liberation from Auerbach's plexus of guinea-pig ileum.

The effect of INDO, a PGE synthesis inhibitor, on ACh output from Auerbach's plexus of guinea-pig ileum was investigated. INDO (15-45 mum/ml) failed to alter significantly either spontaneous ACh output or ACh output induced by field stimulation. It is concluded that PGE plays no physiological role in ACh liberation from this tissue.