Molecular structure of 1,7-dichlorotetradecaphenylheptasilane as a model of poly(diphenylsilane)

The molecular and crystal of 1,7-dichlorotetradecaphenylheptasilane Cl(SiPh₂)₇Cl

1 Dedicated to Prof. Dr. H. Sinn on the occasion of his 60th birthday

(I) was determined. The molecule has a helical conformation with the torsion angles SiSiSiSi in the range of 154°–162°. Crystal I is built of infinite polysilane chains extended along the [111] direction and separated by solvating benzene and toluene molecules.     

Orbital hydatid cyst manifested as expanding exophthalmos following blunt orbital trauma

A 14-year-old boy suffered right blunt orbital trauma. X-ray revealed a compressed fracture of the right ethmoidal sinuses. Three months after the trauma, progressive, painless right proptosis developed. Ocular examination revealed a severe proptosis and pronounced down displacement of the right globe without signs of orbital inflammation. A well-demarcated, extraconal right orbital cystic mass was seen on computerized tomography scan. The cyst contents were aspirated and found to contain echinococcal scolices and "hydatid sand." Hypertonic saline was injected and the cyst was excised. Progressive proptosis after blunt orbital trauma in patients from endemic areas should be suspected of being an orbital hydatid cyst.     

Acute endotoxemia in rats induces down-regulation of V2 vasopressin receptors and aquaporin-2 content in the kidney medulla

BACKGROUND: Endotoxemia can lead to fluid metabolism alterations despite unchanged or elevated plasma vasopressin (VP) levels, suggesting a refractoriness of the kidney to the effect of the peptide. To test this hypothesis, we examined the effect of lipopolysaccharide (LPS) injection on the expression of V2 receptors and aquaporin-2 in the kidney. METHODS: Plasma VP and urine osmolality, and binding of [3H]VP to kidney membranes, Western blot, and immunohistochemical analysis of aquaporin-2, in situ hybridization for V2 VP receptors and cytokines mRNAs were measured in the kidney 3 to 24 hours after LPS injection, 250 microg/100 g, intraperitoneally. RESULTS: LPS injection caused prolonged decreases in urine osmolality (up to 24 hours) without significant changes in plasma levels of sodium or VP. This was associated with marked decreases in V2 VP receptor mRNA and VP receptor number in the kidney, which were evident for up to 12 hours after LPS injection. Aquaporin-2 in kidney inner medulla was also reduced by about 50%. LPS induced interleukin (IL)-1beta in the kidney medulla by 3 hours, reached maximum at 6 hours, and started to decline by 12 hours, while it increased IL-6 mRNA significantly only at 3 hours. Interleukin mRNA expression was absent in kidneys of control rats. In vitro incubation of kidney medulla slices with IL-1beta reduced VP binding. CONCLUSION: The inflammatory response to acute endotoxemia down regulates V2 VP receptors and aquaporin-2 of the kidney inner medulla resulting in prolonged impairment of the renal capacity to concentrate urine.     

Synthesis and evaluation of oxazaborolidines for antibacterial activity against Streptococcus mutans

Several representative oxazaborolidines have been synthesized and evaluated against S. mutans for antibacterial activity. This is the first reported antibacterial activity of this class of compounds. The minimal inhibitory concentration values ranged from 0.53 to 6.75 mM.     

Recent advances in the medicinal chemistry of alpha-aminoboronic acids, amine-carboxyboranes and their derivatives

This article describes recent developments in the synthesis and biological activity of alpha-aminoboronic acids, amine-carboxyboranes and their derivatives as potential therapeutic agents. alpha-Amino acid analogues are of considerable interest as inhibitors of enzymes involved in amino acid and peptide metabolism. In particular, alpha-amino alkylphosphonic acids and alpha-amino alkylboronic acids, in which the carboxyl group of amino acids is replaced by a phosphonic acid or boronic acid function, respectively, constitute a unique class of amino acid mimics from which a number of potent enzyme inhibitors have been synthesized. The inhibitory activity mainly stems from the fact that the tetrahedral phosphonic moiety or the tetrahedral adduct of electrophilic boronic acid is a good mimic of the putative tetrahedral transition state or intermediate encountered in the enzymatic hydrolysis or formation of peptides. Since the peptide hydrolysis and formation invariably involves the tetrahedral high energy species in the course of the reaction, these amino acid mimics serve as a general key element for inhibitors of a broad spectrum of proteases and peptide ligases. Serine protease inhibitors provide promising compounds having a P site binding moiety and a boronic acid chelating moiety. The compounds have been shown to have high inhibitory activity.     

The histologic grade is a main prognostic factor for patients with intracranial ependymomas treated in the microneurosurgical era: an analysis of 258 patients

BACKGROUND: Ependymomas account for 3-5% of all intracranial malignancies and occur most often in children and young adults. These neoplasms continue to generate considerable controversy with regard to their rational clinical management. It has been shown that the histologic classification of ependymoma is a significant predictor of clinical outcome in patients with ependymoma. METHODS: Ependymomas from 258 patients who underwent microsurgery at a single institution were evaluated histologically to elucidate the prognostic utility of a recently proposed grading scheme. Pathologic and clinical data then were compared using univariate and multivariate analyses. RESULTS: Increasing grade of ependymoma malignancy was found to be associated strongly and independently with worse clinical outcomes in terms of both event-free survival and overall survival. The effect of radiotherapy also was found to be related to histologic grade and was more beneficial for patients who had anaplastic ependymomas and had undergone complete tumor removal. CONCLUSIONS: The application of a uniform diagnostic criteria for grading ependymomas highlighted the key role of tumor histology in clinical outcome in a cohort of patients who were treated in the microsurgical era. The recently proposed grading scheme is likely to be practically useful, reproducible, and clinically applicable.     

Consequences of a short pulse of pesticide exposure for survival and reproduction of Gammarus pulex

The aim of the present study was to examine the effects of a short and environmentally realistic pulse exposure of different life stages of the freshwater amphipod, Gammarus pulex, to the pyrethroid insecticide, esfenvalerate. We were particularly interested in determining the extent to which detectable effects on key life-history traits persisted following cessation of a brief exposure to this pesticide. Our results indicate that environmentally realistic exposure concentrations of this widely used insecticide can have a significant effect on the survival and reproduction of Gammarus pulex. Comparison of LC(50) values indicates that G. pulex has a similar sensitivity to esfenvalerate as the standard test invertebrate, Daphnia magna and is more sensitive than other common stream invertebrates. Despite 100% survival during pulses of up to 2 microg l(-1), mortality increased, in some cases markedly, following transfer to clean conditions. Pulse exposure to esfenvalerate at concentrations in the range 0.1-0.6 microg l(-1) for as little as 1h can have effects on G. pulex survival, pairing behaviour, and reproductive output that can still be detected at least 2 weeks following the pulse. Reproductive traits were very sensitive to esfenvalerate, and exposure to 0.05 microg l(-1) for 1h led to immediate disruption of reproducing pairs, release of eggs or offspring from the brood pouch, and substantial delays in pair formation and subsequent reproduction following transfer to clean water. The kinds of effects on reproductive behaviour observed in this study could potentially impact the population dynamics of G. pulex in the field. Whether such effects occur will depend on the frequency, duration, timing, and spatial extent of pesticide exposure in freshwater stream ecosystems, about which relatively little is known. Such information is essential if effects on non-target aquatic species are to be more accurately assessed.     

Modified radical vaginal hysterectomy with or without laparoscopic nerve-sparing dissection: a comparative study

OBJECTIVE: Nerve-sparing dissection of the lateral portion of the cardinal ligament (paracervical lymphadenectomy) has been recently developed with the goal of reducing the late urinary adverse effects of radical hysterectomy without impairing the outcome. This work has been carried out in order to investigate the influence of additional paracervical lymph node dissection at the time of laparoscopically assisted modified radical hysterectomy on outcome and urinary sequelae. METHODS: A total of 95 patients underwent a modified radical hysterectomy using a combined laparoscopic and vaginal approach since 1991. In 47 of these patients treated since 1996 an additional laparoscopic paracervical lymphadenectomy was performed. The operative, postoperative, and survival outcomes were assessed. In 60 patients, 32 and 28 in the groups of patients with or without paracervical dissection, respectively, a careful interview on urinary symptoms was conducted by an independent investigator. RESULTS: Paracervical dissection involves no operative complication and lenghthens the postoperative urinary retention, but has no adverse influence on long-term urinary discomfort. The yield of paracervical dissection is negligible for small tumors: no positive node was found in 38 patients with tumors less than 2 cm in diameter. The outcome of patients after minimal access surgery for tumors less than 2 cm is excellent whether or not a paracervical dissection has been performed. CONCLUSION: Paracervical dissection does not worsen the late urinary symptoms after vaginal radical hysterectomy. It has a limited value in the surgical management of small-size (less than 2 cm) cervical cancers, although it may prevent long-term lateropelvic recurrences.