Effects of periodic weight support in a simulated weightless environment in preventing bone demineralisation.

Anti Orthostatic Hypokinetic posture in rats by tail suspension for 15 days (d) simulates the deconditioning effects of weightlessness on the weight bearing bones. The present study evaluates the effects of daily 4 hour (h) weight support (WS) during simulated weightlessness (S-W) in preventing these changes. Adult male albino rats were divided into three groups as (i) Control (CON, n = 12), (ii) Hind limb unweighing by tail suspension for 15 d (HU, n = 18), (iii) HU with daily 4 h WS (4 HRWS, n = 11). After 15 d tibia from all the animals were removed and subsequently dried, ashed and then calcium content of the bones were determined. HU showed reductions in the water content by 35.8%, organic matrix by 12.2% and calcium content by 33.4% of tibia. 4 h WS during S-W resulted in complete prevention of water loss and organic matrix loss and partial prevention of the loss of calcium content. Calcium content of tibia in 4 HRWS remained 15.2% less as compared to CON. These findings indicate that 4 h WS is partially successful in preventing the demineralisation effects of S-W on weight bearing bone tibia.

Bone changes during simulated weightlessness in rats.

Weightless environment due to prolonged Space mission results in decreased mineralisation of the weight bearing bones. Hind limb unweighting (HU) in rats by tail suspension was used to simulate the effect of weightlessness on tibia. Adult male albino rats were divided into two groups as (i) Control (CON, n = 12) and (ii) HU for 15 days (HU, n = 18). After 15 days of HU tibia from all the animals were removed and subsequently dried and ashed. The calcium content of these bones were then determined. HU resulted in atrophic changes in the weight bearing bone, tibia, due to the reductions of water content (-35.8%), organic matrix (-12.2%) and calcium content (-33.4%). The reduction in the dry wt of tibia (-13.5%) was due to proportionate reductions in the organic matrix and total mineral content of the bone. The reduction in the mineral content was solely due to the reduction in calcium content of the bone.

Physiological properties of rat hind limb muscles after 15 days of simulated weightless environment.

Weightlessness during space mission results in atrophic changes in those muscles which have maximum weight bearing function and consist primarily of slow twitch fibres. In the present study an animal model was designed to evaluate the effects of 15 days of hindlimb unloading (HU) in rats by tail suspension on the (i) weight of gastrocnemius (G), plantaris (P), both predominantly having fast twitch fibres and soleus (S) muscle, predominantly having fast twitch fibres and (ii) contractile properties viz peak twitch contraction (Pt) and peak tetanic contraction (Po) of GPS muscle. HU rats showed significant weight reductions of G (-17.9%), P (-13.3%) and S (-41.2%) muscles. Pt and Po were also reduced in HU group but when these were expressed per gm of GPS muscle, no significant changes in Pt and Po were observed. These findings confirm that HU in rats result in maximum atrophic change in those muscles which have predominantly slow twitch fibres and reductions in contractile properties of muscles are in proportion to reduction in muscle weight. Also, HU by tail suspension provides a good ground based model for developing the deconditioning of muscles as applicable to weightlessness of space and offers a scope for the development of various countermeasures.

Pneumocystis carinii pneumonia in human immunodeficiency virus infected patients in Bombay: diagnosed by bronchoalveolar lavage cytology and transbronchial lung biopsy.

We report Pneumocystis carinii pneumonia (PCP) diagnosed by bronchoalveolar lavage cytology and transbronchial lung biopsy in three out of five human immunodeficiency virus (HIV) positive adult patients presenting with interstitial pneumonitis. One of these patients was serologically positive for HIV at the time of presentation and the remaining two patients were detected to be HIV positive on follow up after the diagnosis had been established. All the three patients were treated with co-trimoxazole. One patient recovered and was discharged; another patient improved with treatment but died after jugular vein cannulation and the third patient succumbed to cryptosporidial diarrhoea. The remaining two patients with non-specific interstitial pneumonitis treated with prednisolone and bronchodilators were recovered and were discharged from the hospital.

Bioequivalence studies of celiprolol in healthy human volunteers.

Thus bioequivalence between the two products was established by undertaking this study. From table 1 it can be seen that the standard deviation at the various sampling points is high indicating varying absorption rates in individual volunteers, but this was observed in case of both the products. Also, since the study design was complete crossover, this high standard deviation was not due to any study design variable. As celiprolol shows non-linear1 dose related absorption kinetics this high value of standard deviation may be due to the intersubject variation during the absorption process. However all the pharmacokinetic parameters showed a comparable profile when statistically evaluated for any significant difference between the two products.

The foetal immune response to maternal tetanus toxoid immunization.

Paired maternal and cord blood samples were collected at delivery from 150 women who received varying doses of tetanus toxoid during pregnancy. Tetanus specific IgM and IgG antibodies were measured in them by standard ELISA with a sensitivity for IgM of 0.001 mg/ml, and for IgG of 0.0003 IU/ml. In 22 infants an additional estimation of tetanus antibody was made 1 month after birth. The presence of specific IgM in 78% of cord samples established an active foetal immune response. The titre did not alter significantly with the number of TT doses given to the mother. Foetal IgM rose in 60% of cases at one month of age compared to cord blood levels. At this time IgG levels were uniformly diminished in accord with a maternally derived passively transferred antibody. No switch of foetal IgM to IgG production was evident. The foetal immune response thus did not confer active protection against tetanus.