Brain-derived neurotrophic factor in megakaryocytes

The biosynthesis of endogenous BDNF has thus far been examined in neurons where it is expressed at very low levels, in an activity-dependent fashion. In humans, BDNF has long been known to accumulate in circulating platelets, at levels far higher than in the brain. During the process of blood coagulation, BDNF is released from platelets which has led to its extensive use as a readily accessible biomarker, under the assumption that serum levels may somehow reflect brain levels. To identify the cellular origin of BDNF in platelets, we established primary cultures of megakaryocytes, the progenitors of platelets, and found that human and rat megakaryocytes express the BDNF gene. Surprisingly, the pattern of mRNA transcripts is similar to neurons. In the presence of thapsigargin and of external calcium, the levels of the mRNA species leading to efficient BDNF translation rapidly increase. Under these conditions, pro-BDNF, the obligatory precursor of biologically active BDNF, becomes readily detectable. Megakaryocytes store BDNF in α-granules, with more than 80% of them also containing platelet factor 4. By contrast, BDNF is undetectable in mouse megakaryocytes, in line with the absence of BDNF in mouse serum. These findings suggest that alterations of BDNF levels in human serum as reported in studies dealing with depression or physical exercise may primarily reflect changes occurring in megakaryocytes and platelets, including the ability of the latter to retain and release BDNF

The anti-apoptotic factor Bcl-2 can functionally substitute for the B cell survival but not for the marginal zone B cell differentiation activity of BAFF.

The TNF family ligand B cell-activating factor (BAFF, BLyS, TALL-1) is an essential factor for B cell development. BAFF binds to three receptors, BAFF-R, transmembrane activator and CAML interactor (TACI), and B cell maturation antigen (BCMA), but only BAFF-R is required for successful survival and maturation of splenic B cells. To test whether the effect of BAFF is due to the up-regulation of anti-apoptotic factors, TACI-Ig-transgenic mice, in which BAFF function is inhibited, were crossed with transgenic mice expressing FLICE-inhibitory protein (FLIP) or Bcl-2 in the B cell compartment. FLIP expression did not rescue B cells, while enforced Bcl-2 expression restored peripheral B cells and the ability to mount T-dependent antibody responses. However, many B cells retained immaturity markers and failed to express normal amounts of CD21. Marginal zone B cells were not restored and the T-independent IgG3, but not IgM, response was impaired in the TACI-IgxBcl-2 mice. These results suggest that BAFF is required not only to inhibit apoptosis of maturating B cells, but also to promote differentiation events, in particular those leading to the generation of marginal zone B cells

The effectiveness and efficiency of ovulation induction agents in mares

Study 1: A retrospective analysis of the effects of hCG and deslorelin on the reproductive efficiency on two commercial horse farms. Reproductive data from two central Illinois horse farms was analyzed to compare the effectiveness of hCG (Chlorulon™) and a sustained release implant formulation of deslorelin (Ovuplant™) for inducing ovulation and their overall effect on reproductive efficiency. Data were collected over 3 consecutive years, from 1999-2001; a total of 1422 cycles were examined from 658 mares. Of the 1422 cycles examined, 383 were treated with hCG, 451 with deslorelin and 583 cycles were untreated. Mares in this study were over 2.1 times more likely to become pregnant if ovulation was induced (p45 mm (p=.001). Time from treatment to ovulation was affected by follicle size at time of treatment and by treatment given. When treatment was given at follicle sizes from 35 mm-39 mm, time to ovulation was shorter with deslorelin (2.02 days) than with hCG (2.68days) (p=.000). The number of palpations was not decreased by the use of ovulation induction but follicle size at administration and day of administration showed a positive effect on reducing the number of palpations. Administration of either agent at the first breeding examination when follicles were less than 35 mm in diameter decreased the number of palpations per cycle by one in comparison to non-treated mares. (p=.009) Fewer artificial inseminations per cycle were performed using deslorelin for follicles between 35 and 44 mm compared no treatment [35-39 mm follicles (p=.000): deslorelin 1.21 AI, untreated 1.39 AI; 40-44 mm follicles(p=.000): deslorelin 1.16 AI, untreated 1.48 AI] . Administration of either hCG or deslorelin to mares possessing a <35 mm follicle at the first breeding exam decreased the number of artificial inseminations required per cycle by 1 (p=.001). Both agents performed equally well at inducing ovulation within 48 hours of administration. Deslorelin appeared more consistent in decreasing the days to ovulation in comparison to hCG . Deslorelin decreased the days to ovulation at <35 mm follicles (p=.001)[deslorelin, 2.34 days, hCG 2.57days, untreated 3.54days], 35-39 mm follicles (p=.000) [deslorelin 2.02 days, hCG 2.68 days, untreated 3.87 days] and 40-44mm follicles (p=.000) [deslorelin 2.10 days, hCG 2.47 days, untreated 3.49 days] , Human chorionic gonadotropin only decreased the days significantly on follicles sized between 35-39 and 40-44 mm. Deslorelin also significantly decreased the days to ovulation over hCG at follicles sized between 35-39 mm. Use of these agents in a commercial breeding setting appears to be of value for improving pregnancy rate and decreasing the time to ovulation for improved timing of insemination. Management of the estrus cycle of the mare will determine if ovulation induction decreases the number of palpations and artificial inseminations per cycle. Management schemes must be considered in evaluating effectiveness of ovulation induction drugs since time of administration within the cycle and size of follicle at administration appear to affect reproductive efficiency. Study 2: Effect of deslorelin sustained release implants on the interovulatory period and response to PGF2 administration 6 days after ovulation Ovuplant™ is a sustained release implant that contains the gonadotropin releasing hormone (GnRH) agonist deslorelin. Subcutaneous administration to a mare during estrus will induce ovulation within 48 hours. Clinical evidence suggests that Ovuplant™ causes an increase in the interovulatory period of mares not conceiving on the treated cycle. A down regulation of the hypothalamic pituitary axis is thought to be the main cause of the increased interovulatory interval but no investigation has occurred concerning the function of the corpus luteum formed by ovulation induction by Ovuplant™. This study was performed using six teaching mares at the University of Illinois Veterinary Teaching Hospital in a cross over design clinical trial with four treatment cycles: a control (untreated cycle), a natural cycle with luteolysis induced with prostaglandin F2 alpha (PGF2α), a cycle with ovulation induced with Ovuplant™, and a final cycle with ovulation induced with Ovuplant™ and luteolysis induced with prostaglandinF2alpha (PGF2α). Progesterone levels for assessment of corpus luteum function were determined every three days during the diestrus period and days between ovulations on each treatment cycle determined the interovulatory period. The goals of the study were to determine the effect of Ovuplant™ administration on the interovulatory period, to examine the progesterone production of the corpus luteum formed after ovulation induction with Ovuplant™, and to determine the response of the corpus luteum formed by Ovuplant™ to induced luteolysis. Progesterone levels differed between control mares and mares induced to ovulate with Ovuplant and administered prostaglandin 6 days after corpus luteum formation (p=.02). The interovulatory periods of mares treated with Ovuplant™ (26.00d) did not differ significantly from untreated mares(21.67 days) (p=..01). The interovulatory periods of untreated mares administered prostaglandin (11.8 days) differed significantly from those treated with Ovuplant™ (26.00days) (p=.01). Four mares treated with Ovuplant™ experienced delayed returns to estrus of 3-25 days. Ovuplant™ did not induce a corpus luteum which differed in progesterone production or its ability to respond to PGF2α. Ovuplant™ appears to extend the interovulatory period of sensitive mares

Transcriptomic Signature of Radiation Response in Li-Fraumeni Syndrome

Li-Fraumeni Syndrome (LFS) is an inherited cancer predisposition disorder associated with a germline mutation in the TP53 tumour suppressor gene. Impaired p53, important in the DNA damage response, has been shown to increase risk of radiation-induced second malignancy (RISM) in LFS patients. We hypothesize that a transcriptomic signature of RISM risk in LFS can be established and used as a predictive tool. LFS patient skin-derived fibroblast cell lines were used to demonstrate transcriptomic differences in patients that developed a RISM relative to those with long-term disease-free survival (LTDFS) post-radiation therapy. Potential RISM signature genes identified were additionally screened for involvement in radiation response and tumorigenic priming. The interconnected Wnt and hedgehog signaling pathways encompassed many of the proposed genes. Development of a RISM signature in LFS has potential to optimize treatment for LFS patients including modification of initial treatment and post-radiation surveillance for those considered high risk of RISM.M.Sc

Tierexperimentelle Untersuchungen am Dunndarm-Invaginationsventil bei der kontinenten Ileoblase. [Experimental studies on the small-intestine invagination valve in continent ileal bladder]

A method for constructing a continent ileal bladder was tested in dogs. The requirements for a continent ileal bladder: i.e., continency, reservoir function, and prevention of reflux, could be fulfilled in our experimental study

Dynamics of the continent ileal bladder. An experimental study in dogs

A continent ileal bladder was constructed in six dogs. The most important requirements for a continent ileal bladder as a reliable mechanism of continency and for prevention of back flow in the ureters could be achieved by two intussusception valves (nipples) of small bowel in opposite directions. The dynamics of these "nipple valves" were studied electromanometrically and radiologically. These experiments showed that these intussusception valves did not binder a free flow in the isoperistaltic direction and did prevent reflux in the antiperistaltic direction