Gas chromatographic assay of methyltestosterone in tablets.

A simple gas chromatographic procedure has been developed for the determination of methyltestosterone in bulk powders and in tablets. Two new silyl ether derivatives of methyltestosterone have been prepared using dimethylethylsilylimidazole (DMESI) and dimethylisopropylsilylimidazole (DMiPSI). The method is accurate and selective for methyltestosterone within the concentration range 0.1-1.5 micrograms microliters-1.     

Dynamic contrast-enhanced MR imaging assessment of vascularized free fibular grafts

Magnetic resonance (MR) imaging may be a noninvasive method for assessing perfusion of vascularized bone grafts placed for treatment of avascular necrosis. One proximal femur of seven beagles was devascularized, with insertion of a vascularized fibular graft. MR imaging at 1 week (seven dogs) and 6 weeks (five dogs) after surgery included pre- and postcontrast spin-echo sequences, unenhanced twodimensional time-of-flight (TOF) vascular imaging, and dynamic gradient-echo imaging during infusion of gadolinium. Relative signal intensity values of selected regions obtained from the dynamic gradientecho images were plotted as percent enhancement versus time. In the operated hip, MR imaging did not show enhancement in six of seven femoral heads and greater trochanters at 1 week after surgery, with similar results after 6 weeks. MR imaging of fibular grafts 6 weeks after surgery showed an initial rapid increase in enhancement and a subsequent slower increase in five of five dogs, although no enhancement was seen in six of seven dogs at 1 week. These findings contrasted with a rapid initial increase in enhancement followed by slow decline in non-operated hips. Two-dimensional TOP imaging did not show the vascular pedicle of the graft in any dog. Findings of radionuclide bone scanning performed 1 week after surgery were consistent with devascularization of the operated femur and fibular graft. However, tetracycline distribution and histologic findings confirmed the viability of five of five grafts within the devascularized femurs 6 weeks after surgery. Thus, dynamic contrast-enhanced MR imaging at 6 weeks after surgery is valuable for assessing vascular bone graft perfusion, while similar imaging at 1 week may suggest otherwise.     

Time course of hypo-osmotic swellings of human spermatozoa: evidence of ordered transition between swelling subtypes

The hypo-osmotic swelling test (HOST or HOS test) usually takes into consideration the total HOS response value with no emphasis either on the value of the response subtypes or the response evaluation time. This study investigated the time course of HOS responses and analysed their physiological relevance. Raw semen spermatozoa and Percoll washed spermatozoa were used in the experiment. The morphological changes in the sperm tail were monitored by incubating the spermatozoa in the hypo- osmotic solution for 16 different time periods. The HOS reactive spermatozoa and the type of HOS reaction (swelling subtypes) of the samples subjected to different duration of treatment were identified under a phase contrast microscope. Also the fate of individual spermatozoa in a hypo-osmotic environment were monitored for 30 min. In spermatozoa exposed to a hypo-osmotic solution, the motility lasted usually less than 2 min and motility characteristics were uniquely different from that of the spermatozoa under iso-osmotic conditions. The HOS response development was permanent but the motility loss due to hypo-osmotic shock was reversible up to 1 min of incubation. There was an indication of ordered transition among the HOS swelling subtypes apparently initiating with subtype b destined to c, d, e, f and g. Further, the subtypes a and g showed gradual decrease and increase, respectively, while subtype b showed abrupt initial increase and then gradual decrease. Transition from b to g could be direct or via one or more than one subtypes. Ultrastructure based analysis indicated that HOS response subtypes are the apparent reflection of the differences in the cytoskeletal assembly of the sperm tail and thus may be identifying different physiological variants in the sperm population. These results indicate that shorter incubation is essential to document the kinetics of various HOS responses but the conventional HOS test misses these important HOS features because of lengthy incubation. Since the time course of ordered transition of HOS responses will vary more than the total HOS response in semen of different aetiologies, the importance of HOS response subtypes and response evaluation time should be taken into consideration when applying HOS test.      

Prevention of skin tumors induced by 7,12-dimethylbenz(a)anthracene in mice by black seed oil

The effect of topical application of black seed oil on 7,12-dimethylbenz(a)anthracene (DMBA)-induced skin tumors in BALB/c mice was investigated. Topical application of chemically extracted oil (C.O.) and naturally extracted oil (N.O.) highly prevented the appearance of skin tumors in experimental animals. Skin tumors (papillomas and carcinomas) were initiated by application of 300 mu g DMBA (on days 1,8) followed by applying 0.5 mg croton oil, biweekly until the end of the experiment (25 weeks). The application of N.O. completely prevented the appearance of skin tumors in mice of group 3 versus a tumor incidence of 78.9% in animals of group 1 (carcinogenic control) (cc). Painting the skin of mice with C.O. (group 2) significantly reduced the tumor incidence to 14.2%. Moreover, a significant decrease was observed in number of mice bearing tumors, and number of tumors per mouse in group 2. Multiplicity was also decreased but insignificantly in the same group. The treatment with C.O. and N.O. insignificantly increased the rate of mice survival as compared to that of animals of group 1.     

Intracranial cavernoma. Surgical results of 47 cases

We report the surgical results in a series of 47 patients with cerebral cavernous malformation who had undergone surgery between 1973 and 1994, with a follow up ranging from 12 months to 24 years (mean: 4 years). They were divided in there groups according to their initial clinical presentation: epilepsy (31 cases), hemorrhage (11 cases) and neurological deficit (5 cases). Surgery consisted of cavernoma resection only (11 cases) or its extension to surrounding gliotic tissue (36 cases). Results are satisfactory: no surgical mortality, low morbidity (4 cases), no recurrent hemorrhage, seizures disappearance with anticonvulsant therapy stop (4 cases) or alleviation (20 cases). Only one patient died far from surgery (6 months) consequently to his initial bleeding, while all the others lead a normal active life. The therapeutic management, compared to the literature, pleads in favour of intentionally surgical attitude and gliotic tissue removal as often as reasonably possible.