Reversible ischemia determined by xenon-enhanced CT after 90 minutes of complete basilar artery occlusion

Intraarterial thrombolytic therapy decreases mortality in the treatment of acute basilar artery occlusion. An acute decrease in cerebral blood flow (CBF) (<12 mL/100 g per minute) has been reported to invariably result in infarction. We report a case of acute basilar artery occlusion, recanalized within 90 minutes, with reversal of CBF of less than 6 mL/100 g per minute. After reperfusion, areas with persistent CBF of 6 mL/100 g per minute resulted in infarctions on subsequent CT studies. Parenchymal viability is possible after 90 minutes of posterior CBF of 6 mL/100 g per minute.     

Overexpression of VEGF in testis and epididymis causes infertility in transgenic mice: evidence for nonendothelial targets for VEGF

Vascular endothelial growth factor (VEGF) is a key regulator of endothelial growth and permeability. However, VEGF may also target nonendothelial cells, as VEGF receptors and responsiveness have been detected for example in monocytes, and high concentrations of VEGF have been reported in human semen. In this work we present evidence that overexpression of VEGF in the testis and epididymis of transgenic mice under the mouse mammary tumor virus (MMTV) LTR promoter causes infertility. The testes of the transgenic mice exhibited spermatogenic arrest and increased capillary density. The ductus epididymidis was dilated, containing areas of epithelial hyperplasia. The number of subepithelial capillaries in the epididymis was also increased and these vessels were highly permeable as judged by the detection of extravasated fibrinogen products. Intriguingly, the expression of VEGF receptor-1 (VEGFR-1) was detected in certain spermatogenic cells in addition to vascular endothelium, and both VEGFR-1 and VEGFR-2 were also found in the Leydig cells of the testis. The infertility of the MMTV-VEGF male mice could thus result from VEGF acting on both endothelial and nonendothelial cells of the male genital tract. Taken together, these findings suggest that the VEGF transgene has nonendothelial target cells in the testis and that VEGF may regulate male fertility.     

The choice of the optimal schedules in the vaccination procedure against influenza in elderly subjects

The paper describes a clinical case of the cerebral hyperperfusion syndrome, a rare complication of carotid endarterectomy. The syndrome appeared as the generalized convulsive syndrome in the patient in the early postoperative period. In the context of clinical observation, the results of analysis of the literature are presented and the pathogenesis, diagnosis, therapy, and prevention of the cerebral hyperperfusion syndrome considered.     

Increased mortality after successful treatment for Hodgkin's disease

PURPOSE: To determine the impact of treatment toxicity on long-term survival in pediatric Hodgkin's disease. PATIENTS AND METHODS: We studied late events in 387 patients treated for pediatric Hodgkin's disease on four consecutive clinical trials at St Jude Children's Research Hospital from 1968 to 1990. Relative risks, actuarial risks, and absolute excess risks for cause-specific deaths were calculated. RESULTS: As of April 1997, 316 (82%) of patients were alive, with a median follow-up of 15.1 (range, 2.9 to 28.6) years. In this cohort, which represented 5,623 person-years of follow-up, 71 fatal events resulted from Hodgkin's disease (n=36), second malignancies (n=14), infections (n=7), accidents (n=7), cardiac disease (n=6), and asphyxiation (n=1). The 5-year estimated event-free survival (EFS) for the entire cohort was 79.6%+/-2.1 %, which declined to 63.1%+/-4.4% by 20 years. Cumulative incidences of cause-specific deaths at 25 years were 9.8%+/-1.6% for Hodgkin's disease, 8.1%+/-2.6% for second malignancy, 4.0%+/-1.8% for cardiac disease, 3.9%+/-1.5% for infection, and 2.1%+/-0.8% for accidents. Standardized incidence ratios showed excess risk for all second malignancies (12; 95% confidence interval [CI], 8 to 17), acute myeloid leukemia (81; 95% CI, 16 to 237), solid tumors (11; 95% CI, 7 to 16), and breast cancer (33; 95% CI, 12 to 72). Standardized mortality ratios also showed excess mortality from cardiac disease (22; 95% CI, 8 to 48) and infection (18; 95% CI, 7 to 38). CONCLUSION: Compared with age- and sex-matched control populations, survivors of pediatric Hodgkin's disease who were treated before 1990 face an increased risk of early mortality related to second cancers, cardiac disease, and infection.     

Dynamical and structural behavior of hydroxyethylcellulose hydrogels obtained by chemical gelation

Rheological, dynamical, de‐swelling, turbidity, and structural features during gelation with a chemical cross‐linking agent of semi‐dilute aqueous solutions of hydroxyethylcellulose (HEC) were investigated at different cross‐linker concentrations. A higher level of cross‐linker leads to faster gelation and stronger incipient hydrogel. The rheological results favor the percolation model. The cross‐linking reaction proceeds over a long time in the post‐gel region, and this produces gels with a solid‐like response. Dynamic light‐scattering experiments reveal a fast and a slow relaxation mode. The slow relaxation time increases and the sample becomes more heterogeneous in the course of gelation. In the post‐gel region, the gels shrink during a long period of time and this phenomenon is accompanied by strong turbidity enhancement. Small‐angle neutron scattering results from samples quenched at a certain stage in the post‐gel regime disclose growth of heterogeneity in the gel with increasing level of cross‐linker addition. At smaller length scales, no effect of cross‐linker addition could be detected on the structural organization, and scattered intensity in this domain suggests that the HEC chains are locally stretched. Copyright © 2006 Society of Chemical Industry     

Construction of secure and fast hash functions using nonbinary error-correcting codes

This paper considers iterated hash functions. It proposes new constructions of fast and secure compression functions with nl-bit outputs for integers n>1 based on error-correcting codes and secure compression functions with l-bit outputs. This leads to simple and practical hash function constructions based on block ciphers such as the Data Encryption Standard (DES), where the key size is slightly smaller than the block size; IDEA, where the key size is twice the block size; Advanced Encryption Standard (AES), with a variable key size; and to MD4-like hash functions. Under reasonable assumptions about the underlying compression function and/or block cipher, it is proved that the new hash functions are collision resistant. More precisely, a lower bound is shown on the number of operations to find a collision as a function of the strength of the underlying compression function. Moreover, some new attacks are presented that essentially match the presented lower bounds. The constructions allow for a large degree of internal parallelism. The limits of this approach are studied in relation to bounds derived in coding theory.     

The intracellular mechanisms of glutaminergic and cholinergic signal transduction in the cerebral cortex

Stimulation of glytamate- and cholinoreceptors by the agonists induced a prolonged calcium and phosphoinositide responses to short-term anoxia or administration of an antioxidant agent in cortical structures. Processes of adaptation essentially modified these responses.