CREB activation mediates plasticity in cultured hippocampal neurons

Activation of cyclic AMP dependent kinase is believed to mediate slow onset, long-term potentiation (LTP) in central neurons. Cyclic-AMP activates a cascade of molecular events leading to phosphorylation of the nuclear cAMP responsive element binding protein (pCREB). Whereas a variety of stimuli lead to activation of CREB, the molecular processes downstream of CREB, which may be relevant to neuronal plasticity, are yet largely unknown. We have recently found that following exposure to estradiol, pCREB mediates the large increase in dendritic spine density in cultured rat hippocampal neurons. We now extend these observations to include other stimuli, such as bicuculline, that cause the formation of new dendritic spines. Such stimuli share with estradiol the same mechanism of action in that both require activity-dependent CREB phosphorylation. Our observations suggest that CREB phosphorylation is a necessary, but perhaps not sufficient, step in the process leading to the generation of new dendritic spines and perhaps to functional plasticity as well.     

Extracellular matrix survival signals transduced by focal adhesion kinase suppress p53-mediated apoptosis

In many malignant cells, both the anchorage requirement for survival and the function of the p53 tumor suppressor gene are subverted. These effects are consistent with the hypothesis that survival signals from extracellular matrix (ECM) suppress a p53-regulated cell death pathway. We report that survival signals from fibronectin are transduced by the focal adhesion kinase (FAK). If FAK or the correct ECM is absent, cells enter apoptosis through a p53-dependent pathway activated by protein kinase C lambda/iota and cytosolic phospholipase A2. This pathway is suppressible by dominant-negative p53 and Bcl2 but not CrmA. Upon inactivation of p53, cells survive even if they lack matrix signals or FAK. This is the first report that p53 monitors survival signals from ECM/FAK in anchorage- dependent cells.     

Ischemia/reperfusion injury in human kidney transplantation: an immunohistochemical analysis of changes after reperfusion

Organs used for transplantation undergo varying degrees of cold ischemia and reperfusion injury after transplantation. In renal transplantation, prolonged cold ischemia is strongly associated with delayed graft function, an event that contributes to inferior graft survival. At present, the pathophysiological changes associated with ischemia/reperfusion injury in clinical renal transplantation are poorly understood. We have performed an immunohistochemical analysis of pre- and postreperfusion biopsies obtained from cadaver (n = 55) and living/related donor (LRD) (n = 11) renal allografts using antibodies to adhesion molecules and leukocyte markers to investigate the intragraft changes after cold preservation and reperfusion. Neutrophil infiltration and P-selectin expression were detected after reperfusion in 29 of 55 (53%) and 24 of 55 (44%) cadaver renal allografts, respectively. In marked contrast, neutrophil infiltration was not observed in LRD allografts, and only 1 of 11 (9%) had an increased level of P-selectin after reperfusion. Immunofluorescent double-staining demonstrated that P-selectin expression resulted from platelet deposition and not from endothelial activation. No statistically significant association was observed between neutrophil infiltration and P-selectin expression in the glomeruli or intertubular capillaries despite the large number of cadaver renal allografts with postreperfusion changes. Neutrophil infiltration into the glomeruli was significantly associated with long cold ischemia times and delayed graft function. Elevated serum creatinine levels at 3 and 6 months after transplantation were also associated with the presence of neutrophils and platelets after reperfusion. Our results suggest that graft function may be influenced by early inflammatory events after reperfusion, which can be targeted for future therapeutic intervention.     

Parathyroid hormone (1-34) increased total body bone mass in aged female rats

Daily subcutaneous administration of bovine parathyroid hormone (PTH)(1-34) stimulates bone formation and increases bone mass in rat tibiae, femora and lumbar spine. However, the effects of PTH on the whole body bone mineral content and density determined by dual energy x-ray absortiometry (DEXA) have not been previously reported in rats. Eighteen-month-old intact female rats were subcutaneously injected daily with 0, 40, 80 or 160 micrograms/kg/day of bovine PTH (1-34) for either 15 or 60 days. Whole body DEXA was performed at 1 day before autopsy, and bone area, bone mineral content (BMC) and bone mineral density (BMD) of the total body were determined. Total femoral, tibial and lumbar spine BMD was also determined ex vivo. Cancellous bone histomorphometry was performed on sections of double-labeled proximal tibial metaphyses. Whole body bone mineral content and density were significantly increased by 60 days, but not by 15 days, of PTH treatment at all dose groups compared with vehicle controls. Lumbar vertebral and total femoral BMD was significantly increased at all doses of PTH by 15 days of administration and further increased by 60 days. All doses of PTH increased trabecular bone area in proximal tibial metaphyses by 15 days and further increased by 60 days. All doses of PTH increased trabecular bone area in proximal tibial metaphyses by 15 days and further increased by 60 days. In proximal tibial cancellous bone, dose-dependent increases in percent labeled perimeter, mineral apposition rate and bone formation rate-bone volume referent were found between 40 and 160 micrograms/kg of PTH treatment by 15 days, and no further increases were found by 60 days. Our results showed that in aged female rats, bovine PTH(1-34) increased bone formation and total body bone mass.     

Surgical sperm retrieval and intracytoplasmic sperm injection as treatment of obstructive azoospermia

Male genital tract obstructions may result from infections, previous inguinal and scrotal surgery (vasectomy) and congenital bilateral absence of the vas deferens (CBAVD). Microsurgery can sometimes be successful in treating the obstruction. In other cases and in cases of failed surgical intervention, the patient can be treated by microsurgical or percutaneous epididymal sperm aspiration (MESA, PESA) or testicular sperm extraction (TESE) and intracytoplasmic sperm injection (ICSI). We present the results of 39 ICSI procedures for obstructive azoospermia in 24 couples. The aetiology of the obstruction was failed microsurgery in 11 patients, CBAVD in nine and genital infections in four. Sperm retrieval was accomplished via MESA in four cases, PESA in 18 cases and via TESE in 11 cases. TESE was only applied when PESA failed to produce enough spermatozoa for simultaneous ICSI. In six patients, the ICSI procedure was performed with cryopreserved spermatozoa after an initial PESA procedure. Fertilization occurred in 47% of the metaphase II oocytes; embryo transfer was performed in 92% of procedures and resulted in a clinical pregnancy in 13/39 procedures. Ongoing pregnancy was achieved in 10/39 procedures. One pregnancy was terminated early after prenatal investigation showed a cytogenetic abnormality (47,XX+18, Edwards syndrome). The other nine pregnancies resulted in the live birth of 10 children, without any congenital abnormalities. Epididymal and testicular retrieved spermatozoa were successfully used for ICSI to treat obstructive azoospermia, and resulted in an ongoing pregnancy in 10 of 24 couples (41.6%) after 39 ICSI procedures, a success rate of 25.6% per treatment cycle and of 27.7% per embryo transfer.     

Obstructive sleep apnea due to endogenous testosterone production in a woman

Quantitative buffy coat (QBC) analysis has been reported to have a high degree of methodical sensitivity in the detection of human filariasis. This study was conducted to evaluate its usefulness in the diagnosis of filariasis using a Dirofilaria immitis/dog model. By necropsy of 244 stray dogs, 40.6% of the animals were found to harbor 1-58 worms of D. immitis (mean 6.5 +/- 8.4 worms/infected dog). The QBC analysis and thick blood smear (TBS) method detected microfilaremia in 31.6% and 21.3% of these dogs, respectively. The results of these two methods were highly correlated with the presence of bisexual worms in the dogs. The QBC analysis was more sensitive (55% versus 39%) and efficient (79% versus 72%) than the conventional TBS method. However, accurate speciation of the microfilariae was impossible using the QBC analysis. Although this technique is more sensitive, simpler, and less time-consuming and does not require as much skill or experience in comparison with the conventional TBS method, the failure in speciation of the parasites may limit its usefulness.     

Activity of (-)-2'-deoxy-3'-oxacytidine (BCH-4556) against human tumor colony-forming units

BACKGROUND: BCH-4556 ((-)-2'-deoxy-3'-oxacytidine) is an L-nucleoside analogue shown to have broad preclinical anti-cancer activity, particularly against solid neoplasms such as prostate, renal, and hepatoma in vitro and in vivo, in contrast to cytosine arabinoside (ara-C) which is preferentially active against leukemia. MATERIALS AND METHODS: The antitumor activity of BCH-4556 was evaluated using human tumor colony-forming unit (HTCFU) assay, in which fresh tumor specimens were taken directly from patients with and without prior chemotherapy. RESULTS: Overall, in vitro responses (50% or less survival compared to untreated controls) were observed in 11% (two of 18), 29% (five of 17) and 50% (nine of 18) of specimens treated for one hour with BCH-4556 at 1, 10 and 100 micrograms/ml, respectively; and 16% (nine of 55), 32% (24 of 74), 48% (35 of 73) and 65% (11 of 17) of specimens treated continuously with BCH-4556 at 0.1, 1, 10 and 100 micrograms/ml, respectively. With the one-hour schedule, a significant difference in response rates was noted between 100 micrograms/ml and 1 microgram/ml (P = 0.02). With the continuous schedule, significant differences in response rates were observed between 1 microgram/ml and 0.1 microgram/ml (P = 0.02), between 10 micrograms/ml and 0.1 microgram/ml (P = 0.0001), as well as between 10 micrograms/ml and 1 microgram/ml (P = 0.01). A trend suggesting the superiority of continuous exposure was observed in paired specimens (n = 18) at comparable drug concentrations. Activity was noted against ovarian (nine of 16 = 56%), renal (three of four = 75%), and melanoma (two of two = 100%) HTCFU at 10 micrograms/ml using the continuous schedule. Comparisons between BCH-4556 and paclitaxel were made in 32 specimens at 10 micrograms/ml using the continuous exposure. Twenty-three specimens showed similar responses with both drugs; seven showed better responses with BCH-4556; and two showed better responses with paclitaxel (P = 0.18). CONCLUSIONS: Promising activity was observed with BCH-4556 against ovarian, renal, and melanoma HTCFU. There appeared to be a positive relationship between BCH-4556 concentration and response using both one-hour and continuous exposures. Continuous exposure to BCH-4556 provided high response rates especially at concentrations above 10 micrograms/ml. For both one-hour and continuous exposures, BCH-4556 had similar, and at times, greater potency than paclitaxel against the same tumor specimens in the present study.     

Phase I/II study of the toxicity, pharmacokinetics, and activity of the HIV protease inhibitor SC-52151

A significant restriction was demonstrated in the ability of herpes simplex virus type 1 virion host shutoff (vhs) mutant viruses to invade the corneal epithelium. Viral replication and invasion was confined to the areas of the cornea which were scarified prior to infection. Differences between wild-type and vhs mutant replication in corneas in vivo were 100- to 1000-fold at all timepoints postinfection. Smaller but still significant growth restrictions were observed in cultured corneal cells. This difference between in vitro and in vivo is not likely to be due to differences in cell cycle status since vhs-induced RNA degradation can occur in both cycling and noncycling cells in vitro. The vhs function is therefore important for invasion of the cornea and secondarily the nervous system and is thereby required for efficient establishment of latency.     

Hemostatic and fibrinolytic indices in neonatal foals with presumed septicemia

Gerbils learned to approach a spatial-olfactory stimulus that signaled access to their pairmate. Experiments 1 and 3 used a discrimination procedure in which 1 conditioned stimulus (the CS+) was presented immediately before access to the pairmate and another (the CS-) was presented alone. Both male and female gerbils came to approach the CS+ sooner than the CS- and spent more time near the CS+ than the CS-. Discrimination learning was facilitated by making the CS+ and CS- spatially distinct (Experiment 3). Learning also was demonstrated in male gerbils, using a between-subjects design with a single CS. Pairing the CS with the opportunity for social interaction resulted in greater approach to the CS within 10 trials than presenting the CS and social opportunity in an unpaired fashion (Experiment 2). These findings demonstrate social-affiliative learning in the Mongolian gerbil. Similarities and differences between these findings and sexual conditioning effects in other species are discussed.