Lessons learned from the DIASTAT vascular access graft

In male Syrian hamsters, short days induce regression of the reproductive system, but eventually spontaneous recrudescence occurs ensuing from refractoriness to the inhibitory photoperiod. Although the photoperiod of 12 L:12 D (12 h light:12 h dark) may act like a short day by inducing the testicular cycle outlined above, it may fail to evoke the increase of circulating concentrations of prolactin that accompanies testicular recrudescence. This photoperiod may fail to induce photorefractoriness, as indicated by the prolonged low concentrations of prolactin in the blood. Herein, hamsters were exposed to either 8 L:16 D or 12 L:12 D from weaning and by 28 weeks exposure to either photoperiod, the hamsters had large testes following recrudescence from a photoperiod induced-regression). Transfer to 8 L:16 D from 12 L:12 D at 28 weeks resulted in a second testicular regression and recrudescence. In a second experiment, the testes of hamsters moved to 8 L:16 D from 12 L:12 D after 29 weeks exposure to the latter photoperiod similarly regressed and then regrew. Serum concentrations of prolactin decreased in these males after transfer to the shorter daylength but also decreased in hamsters kept under 12 L:12 D both groups were usually below those of hamsters moved to 14 L:10 D. These results show that exposure for 28 or 29 weeks to 12 L:12 D was insufficient to induce photorefractoriness, despite the recrudescence of the testes following involution.     

Is homophobia associated with homosexual arousal?

The authors investigated the role of homosexual arousal in exclusively heterosexual men who admitted negative affect toward homosexual individuals. Participants consisted of a group of homophobic men (n?=?35 ) and a group of nonhomophobic men (n?=?29); they were assigned to groups on the basis of their scores on the Index of Homophobia (W. W. Hudson & W. A. Ricketts, 1980). The men were exposed to sexually explicit erotic stimuli consisting of heterosexual, male homosexual, and lesbian videotapes, and changes in penile circumference were monitored. They also completed an Aggression Questionnaire (A. H. Buss & M. Perry, 1992). Both groups exhibited increases in penile circumference to the heterosexual and female homosexual videos. Only the homophobic men showed an increase in penile erection to male homosexual stimuli. The groups did not differ in aggression. Homophobia is apparently associated with homosexual arousal that the homophobic individual is either unaware of or denies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Scaling of movement velocity: a measure of neuromotor retardation in individuals with psychopathology

The combination of ifosfamide, carboplatin and etoposide (modified ICE), was evaluated for its toxicity and activity in relapsed or refractory aggressive non-Hodgkin's lymphoma. Twenty patients, 14-69 years of age, with relapsed (19 cases) or refractory (one case) aggressive non-Hodgkin's lymphoma were treated with modified ICE therapy, consisting of ifosfamide 6 g/m2 (1.2 g/m2 day 1-5), carboplatin 400 mg/m2 (day 1) and etoposide 500 mg/m2 (100 mg/m2 day 1-5). The regimen was repeated at approximately 28-day intervals. All patients had undergone a doxorubicin-containing regimen before modified ICE therapy. Median total dose of previously received doxorubicin was 406 mg/m2 (range: 200-825 mg/m2). The median interval from diagnosis to modified ICE therapy was 9.4 months (range: 3.6-121 months). Two patients achieved CR and five achieved PR out of 16 patients with measurable lesions (response rate 43.8%; 95% confidence interval 19.0-68.6%). Median overall survival was 227 days (range: 41-552 days) from the start of modified ICE therapy. Myelosuppression was the most serious toxicity, namely 16 patients (80%) and 11 patients (55%) showed grade 4 neutropenia and grade 4 thrombocytopenia after the first course, respectively. Modified ICE therapy might be an active regimen with acceptable toxicity as a salvage chemotherapy in aggressive non-Hodgkin's lymphoma.     

The TASSO vertex detector

The design, construction and performance of a small pressurized drift chamber of low mass and high wire density is described. The chamber forms part of the TASSO experiment at the PETRA e⁺e⁻ storage ring of the DESY Laboratory. First physics results obtained with the chamber are also briefly discussed.     

Biosynthesis of the Myxobacterial Antibiotic Corallopyronin A

Corallopyronin A is a myxobacterial compound with potent antibacterial activity. Feeding experiments with labelled precursors resulted in the deduction of all biosynthetic building blocks for corallopyronin A and revealed an unusual feature of this metabolite: its biosynthesis from two chains, one solely PKS‐derived and the other NRPS/PKS‐derived. The starter molecule is believed to be carbonic acid or its monomethyl ester. The putative corallopyronin A biosynthetic gene cluster is a trans‐AT‐type mixed PKS/NRPS gene cluster, containing a β‐branching cassette. Striking features of this gene cluster are a NRPS‐like adenylation domain that is part of a PKS‐type module and is believed to be responsible for glycine incorporation, as well as split modules with individual domains occurring on different genes. It is suggested that CorB is a trans‐acting ketosynthase and it is proposed that it catalyses the Claisen condensation responsible for the interconnection of the two chains. Additionally, the stereochemistry of corallopyronin A was deduced by a combination of a modified Mosher's method and ozonolysis with subsequent chiral GC analyses.     

Decreased anterior cingulate gyrus metabolic rate in schizophrenia

Although the majority of physicians entering residency training in Canada will enjoy fulfilling careers in their chosen specialty, today's postgraduate training system has its critics. Among them are the new graduates who are not satisfied with the residency positions offered to them and practising physicians who would like to re-enter the system to train in a new specialty but find themselves locked out.     

Summary and recommendations for future research

A novel triblock copolymer of epsilon-caprolactone (CL) and ethylene oxide (E), CL6E90CL6, intended for use in implantable drug-delivery systems, has been subjected to gamma irradiation, in the solid state and in aqueous solution, under different controlled environmental conditions, to assess its stability to a radiation sterilization process. When copolymer matrices were irradiated with doses of irradiation up to 72 kGy in the presence of oxygen, negligible changes were observed in the molar mass, molecular mobility (assessed by pulsed nuclear magnetic resonance spectroscopy) and thermal properties. However, irradiation of matrices in the absence of oxygen (anoxia) induced the formation of cross-links, as indicated by a reduction in the molecular mobility of the copolymer, but without affecting its molar mass and thermal properties. Gamma irradiation of aqueous solutions of CL6E90CL6 in the presence of oxygen induced random polymer chain scission, as evidenced by a reduction in the molar mass, and the formation of a distribution of copolymer chain lengths in solution. Nuclear magnetic resonance relaxation studies showed that irradiation of solutions of CL6E90CL6 at concentrations greater than 4% w/v under anoxic conditions with doses of 54 kGy produced polymer gels with a network structure. These differences in the effects of gamma irradiation on the physicochemical properties of CL6E90CL6 might be germane to the method selected for sterilization of the polymer before its use in implantable drug-delivery systems.