The reaction of the rat thymus to xenotransplantation and immunosuppression

To the complex action of human embryonal neocortex transplanted into the eye anterior chamber and cyclosporin A injected daily to prevent graft rejection rat thymus reacts by accidental involution, layer inversion and vascular disturbances (without hematoma formation). After 3 wks reparative period sets in and by the end of 5th wk thymus approximates to the control in all parameters.     

Bicyclic derivatives of hexahydroaporphine: novel agents that lower intraocular pressure

The aim of this study was to evaluate clinically, histologically and histometrically the use of hydroxyapatite-coated dental implants in conjunction with maxillary sinus augmentation procedures. In 4 adult male Rhesus monkeys (Macaca mulatta) the 3 maxillary molars on 1 side of the jaws were extracted and the remaining bone between the alveolar crest and the floor of the sinus was reduced to 3-4 mm. After 3 months, maxillary sinus augmentation procedures were performed in each monkey and the sinuses were grafted with a porous hydroxyapatite bone graft (Interpore-200). At the same time, 2 hydroxyapatite-coated cylinder implants (IMZ) were immediately placed into the augmented sinuses (i.e. simultaneous-implants-loaded group). Four months later, 2 additional similar implants were placed into the previously augmented sinuses (i.e. delayed-implants-loaded group). After 4 months, the abutment connection was performed and all 4 implants were loaded with a gold-alloy bridge for 6 months (i.e. until sacrifice of the animals). The contralateral side of each monkey received the same treatment with the exception that removal of the maxillary molars was performed 7 months after those in the opposite side, and that the implants in this side were not loaded. Thus, 2 additional study groups (i.e. simultaneous-implants-unloaded group and delayed-implants-unloaded group) were obtained. Clinically, all loaded and unloaded implants were stable the day of sacrifice. Histologically, the grafted sinuses exhibited a significant amount of new bone formation with integration of the porous hydroxyapatite graft particles and hydroxyapatite-coat of the dental implants to the new bone. Histometric analysis indicated that on the loaded side the implants placed simultaneously with the sinus lift procedure exhibited greater direct mineralized bone-to-implant contact than the delayed placed implants. In addition, the percentage of direct mineralized bone-to-implant contact was significantly greater in the residual bone in comparison to the augmented area in all groups. Loading of the implants exhibited a positive effect on the percentage of direct mineralized bone-to-implant contact in the augmented area. It could be concluded that hydroxyapatite-coated implants may be of benefit when used in conjunction with sinus augmentation procedures.     

Measurement of blood volume and red cell mass: re-examination of 51Cr and 125I methods

Comparison of results of red cell mass (RCM) measurement by 51Cr and 125I methods in 119 patients showed virtual equivalence. Both methods have an acceptable coefficient of variation (CV) that is < 5%. The 125I method is simpler and much less expensive. Unrealistically narrow "normal ranges" for RCM are likely to lead to misdiagnosis of polycythemia vera. Upper normal limits of 39 mL/kg (males) and 32 mL/kg (females) are consistent with originally published data in normal persons; use of these limits as criteria would reduce the risk of misdiagnosis. No cases of "stress erythrocytosis" or Gaisbock Syndrome were encountered among the 119 cases reviewed.     

Rate of tetracycline dissolution from tablets and capsules and the biological availability of the antibiotic

Relation between the rate of tetracycline dissolution from tablets and capsules and the biological acceptibility of the antibiotic in the host was studied. The antibiotic dissolution rate from the pharmaceutical forms was determined in a modernized apparatus "Rotary basket" in water, the speed of the basket rotation was 200 r.p.m. In addition the tetracycline blood levels in patients treated with the drug in the above pharmaceutical forms were estimated. It was found that the rate of the antibiotic dissolution characterized the antibiotic biological acceptibility. A test for the dissolution rate was developed. It may be used for estimation of production batches of tetracycline tablets.