Arachidonic acid modulates [14C]stearic acid incorporation into phosphatidylinositol,in human neuroblastoma cells

In the human neuroblastoma cell line SK-N-BE(2), arachidonic acid (AA), supplied in the medium at micromolar concentrations, markedly ehnanced [¹⁴C]stearic acid (SA) (but not [¹⁴C]palmitic acid or [¹⁴C]oleic acid) incorporation into phosphatidylinositol (PtdIns). AA failed to stimulate [¹⁴C]SA incorporation into PtdIns precursors, namely phosphatidic acid and cytidinediphosphodiacylglycerol; furthermore, enhanced [¹⁴C]SA incorporation, brought about by exogenously administered AA, was not restricted to PtdIns tetraenoic species. When cells were pulsed for 1 h with [¹⁴C]SA (either in the presence or absence of AA) and then reincubated in AA- and [¹⁴C]SA-free medium, a marked loss of radioactivity from PtdIns was observed, that however was restricted to molecular species other than tetraenoic. These results are discussed in the light of possible mechanisms through which PtdIns achieves the 1-stearoyl-2-arachidonoyl configuration.     

On the role of agonist-evoked Ca2+ mobilization in sustaining the ongoing phosphoinositide hydrolysis

Stimulation of SK-N-BE(2) cells with 1 mM carbachol (Cch) elicited phosphoinositide (PPI) hydrolysis and a rapid elevation of cytosolic Ca²⁺ concentration ([Ca²⁺]_i) from 115 nM to about 500 nM, followed by a plateau around 200 nM. In myo [³H]inositol-labelled cells, Cch-evoked accumulation of [³H]inositol phosphates (IPs) was not affected when [Ca²⁺]_i was clamped at resting by cell loading with 10 M BAPTA/AM; under these conditions, maximal 1,4,5-inositol trisphosphate accumulation was not reduced either. When [Ca²⁺]_i was clamped around 700 nM by cell treatment with 600 nM ionomycin, Cch-evoked [³H]IPs accumulation was enhanced by less than 20%, but it was impaired by a 30% and a 55% after [Ca²⁺]_i reduction to about 70 nM and 35—50 nM, by cell loading with 20 M or 40 M BAPTA/AM, respectively. These results show that, in SK-N-BE(2) cells, Cch-activated PPI-specific phospholipase C is sensitive to [Ca²⁺]_i but it already operates under suboptimal conditions at resting [Ca²⁺]_i.     

Consumer participation in identifying research and development priorities for power wheelchair input devices and controllers

A focus group comprised of persons who use power wheelchairs and professionals working in the field were asked to participate in a brainstorming session to determine priorities for the development and application of power mobility input devices and control concepts. The group consensus was that durability and reliability are the most important criteria. Essentially, the expectation is that a power wheelchair must work everyday in the way a person needs it and wants it. At the same time, there is a desire to enhance and advance the features of input devices and control systems. Many would say these changes constitute designing "smarter" power wheelchairs, such as systems that can independently detect obstacles and can provide users with more feedback. This paper presents the rationale behind forming this focus group and details of the results of a brainstorming session where ideas were generated and prioritized. The five most important issues as determined by the group are discussed in depth.     

Electrochemical vaginal potential during the estral cycle and pregnancy in the rat

Potentials were measured with nonpolarizable salt electrodes (agar KCl-AgCl) during the estral cycle and pregnancy of the rat. The vaginal fundus is positive in regard to the external end of the vagina and does not present changes associated with the estral cycle. Vaginal-tongue potentials present biphasic cyclic changes associated with the estral cycle, the vagina being (-) during estro and (+) during diestro. Vaginal-abdominal skin potentials present monophasic modifications associated with the estral cycle. Vaginal-tongue potentials registered during pregnancy were (-) on the first day of pregnancy, (+) throughout pregnancy, and (-) on the first day postpartum.     

Renal immunoblastic sarcoma complicating immunosuppressive therapy for wegener granulomatosis

A renal tumor developing in a patient receiving cyclophosphamide (Cytoxan) therapy for Wegener granulomatosis is reported. The tumor was similar histologically to the "immunoblastic" sarcoma that develops in renal allograft recipients as a complication of immunosuppressive therapy. This case report strengthens the cause and effect relationship between immunosuppressive drug usage and the subsequent development of neoplasia.     

Chlorpyrifos-induced delayed polyneuropathy

Chlorpyrifos [0,0-diethyl 0-(3,5,6-trichloro-pyridyl) phosphorothioate] caused delayed polyneuropathy in man. Contrary to previous studies, we report here that it also causes delayed polyneuropathy in the hen, the animal model for this toxicity. The minimal neuropathic dose was 60–90 mg/kg p.o., corresponding to 4–6 times the estimated LD₅₀. Consequently, pralidoxime (2-PAM) in conjunction with atropine was necessary to reverse acetylcholinesterase (AChE) inhibition and cholinergic toxicity in hens given high enough doses of chlorpyrifos to cause neuropathy. Chlorpyrifos was slowly absorbed after single oral doses and the threshold of inhibition (>70%) of neuropathy target esterase (NTE), the putative target for delayed neuropathy, was reached within 5–6 days. High AChE inhibition (>90%), however, was measured within hours after dosing because of the higher potency of chlorpyrifos to inhibit this enzyme. In vitro studies showed that chlorpyrifos-oxon, the active metabolite of chlorpyrifos, was 10–20 times more active against AChE than against NTE, confirming the clinical observation. No differences were seen between human and hen enzymes in this respect. Hen and human brain homogenates contain A-esterases which hydrolysed chlorpyrifos to about the same extent in both species. In conclusion, chlorpyrifos causes delayed polyneuropathy in the hen, as was reported in man. The reasons for previous negative data in the hen are probably due to the relatively lower doses which were used. Judging from in vitro studies with hen and human enzymes, there are no differences in the two species as far as their relative sensitivity to delayed polyneuropathy. It is likely that delayed polyneuropathy would develop in both species only after severe cholinergic toxicity requiring aggressive antidotal treatment.Part of this work was presented at the 25th Annual Meeting of the Society of Toxicology held in New Orleans, LA, USA, March 1986, at the International Symposium on Biochemical and Cellular Indices of Toxicity in Occupational and Environmental Medicine held in Milan, Italy, June 1986, and at the 9th Meeting of the Peripheral Nerve Study Group, Praglia (PD), Italy, August – September, 1989     

Prognostic value of galactose elimination capacity,aminopyrine breath test,and ICG clearance in patients with cirrhosis

Seventy-eight patients with cirrhosis were prospectively followed for up to 20 months, on the average. At entry into the study, galactose elimination capacity, aminopyrine breath test, and ICG clearance were measured. At the end of the study, 27 patients had died. Univariate analysis using the Kaplan-Meier method showed that both quantitative liver function tests (galactose elimination capacity:P<0.025; aminopyrine breath test:P<0.001; ICG clearance:P<0.005) and common clinical and biochemical data (encephalopathy:P<0.001; ascites:P<0.001; serum bilirubin:P<0.005; serum albumin:P<0.001; prothrombin index:P<0.05) were significant predictors of survival. To investigate whether quantitative liver function tests could contribute to a better definition of the prognosis, once Pugh score had already been taken into account, a multiple regression analysis according to the Cox model was performed. Pugh score and galactose elimination capacity resulted in the only independent prognostic covariates. From them a prognostic index was calculated, and the model was validated in an additional sample of 70 patients investigated according to the same protocol. The contribution GEC gave to the assessment of overall prognosis over that obtained using the Pugh score was slight, as estimated by the statistical parameters of the Cox's model, but was significant as assessed by a ROC curve analysis (P=0.05). These data show that all quantitative liver function tests were predictors of survival in cirrhosis, and that the galactose elimination capacity added some new prognostic information to those already available using the Child-Turcotte-Pugh classification.This study was supported in part by a grant from the Italian Ministry of Education (National Project Liver Cirrhosis). Part of this study was presented at the 22nd Meeting of the European Society for Clinical Investigation, Graz, Austria, April 20–23, 1988.     

Fear conditioning in C57/BL/6 and DBA/2 mice: variability in nucleus accumbens function according to the strain predisposition to show contextual- or cue-based responding

The contribution of the nucleus accumbens shell, the dorsal hippocampus, and the basolateral amygdala to contextual and explicit cue fear conditioning was assessed in C57BL/6 (C57) and DBA/2 (DBA) mice showing differences in processing contextual information associated with consistent but non-pathological variations in hippocampal functionality. Mice from both strains with bilateral ibotenic acid or sham lesions located in each area were introduced in a conditioning chamber and exposed twice to the pairing of a tone (2 x 8 s, 2000 Hz, 80 dB) with a shock (2 s, 0.7 mA). On the following day, mice were first exposed to the training context then to the tone in a different context. Freezing behaviour was scored in all situations. C57 showed more freezing to the context than to the tone whereas DBA showed more freezing to the tone than to the context. In C57, both nucleus accumbens and hippocampal lesions impaired acquisition of contextual fear conditioning but paradoxically improved acquisition of cue fear conditioning, whereas amygdala lesions disrupted performance in every task. In DBA, nucleus accumbens lesions, like amygdala lesions, impaired acquisition of both contextual and cue fear conditioning, whereas hippocampal lesions did not produce any effect. The parallelism between the effect of nucleus accumbens and hippocampus lesions in C57, and between the effect of nucleus accumbens and amygdala lesions in DBA points to a variability in nucleus accumbens function according to the strain specialization to develop context- or cue-based responding.     

Radiosurgery in the treatment of the glottic plane carcinoma

During the last 20 years, various conservative surgical techniques have been proposed to treat larynx cancer. On the basis of our various experiences and of the ultrastructural data on the tissues treated with radiowaves, we decided to also use radiosurgery in operations under direct microlaryngoscopy. We select 18 patients suffering from epidermoid carcinoma. These patients had been referred to our ENT clinic at the Polichnico of Palermo between 1999 and 2001. The authors describe the surgical procedures used and emphasize the advantages of radiosurgery in the treatment of larynx cancer.     

Common gene polymorphisms in the metabolic folate and methylation pathway and the risk of acute lymphoblastic leukemia and non-Hodgkin's lymphoma in adults.

Folate and methionine metabolism is involved in DNA synthesis and methylation processes. Polymorphisms in the genes of folate metabolism enzymes have been associated with some forms of cancer. In a case-control study, we evaluated whether four common polymorphisms in methylenetetrahydrofolate reductase (MTHFR C677T and A1298C), methionine synthase (MS A2756G), and methionine synthase reductase (MTRR A66G) genes may have a role in altering susceptibility to adult acute lymphoblastic leukemia (ALL) and non-Hodgkin's lymphoma (NHL). We analyzed DNA of 120 adult ALL, 200 NHL, and 257 healthy control subjects. Individual carrying the MTHFR 677TT genotype showed a 3.6-fold decreased ALL risk [odds ratio (OR) 0.28, 95% confidence interval (95% CI) 0.12-0.72] than wild-types. Similarly, MS 2756GG individuals showed a 5.0-fold decreased ALL risk (OR 0.20, 95% CI 0.02-1.45) than wild-types. In combined results, subjects with the MTHFR 677CT/TT and MS 2756AG/GG genotypes revealed a 3.6-fold ALL risk reduction (OR 0.28, 95% CI 0.14-0.58) and those with the MTHFR 677TT and MTRR 66AG genotypes revealed a 4.2-fold ALL risk reduction (OR 0.24, 95% CI 0.06-0.81). Finally, those with the MS 2756AG/GG and MTRR 66AG/GG genotypes revealed a 2.2-fold ALL risk reduction (OR 0.45, 95% CI 0.10-0.85). Single analysis for NHL did not show any significant difference for all the polymorphisms investigated, but in the low-grade NHL subgroup, we found a 2.0-fold risk reduction for the MTRR 66GG homozygous genotype (OR 0.50, 95% CI 0.25-0.99), which was higher (OR 0.37, 95% CI 0.14-0.85) when analyzed in combination with MS 2756AA genotype. These data are in accordance with the hypothesis that polymorphisms in the genes for folate and methionine metabolism might play a greater role in the occurrence of ALL than NHL by influencing DNA synthesis and/or DNA methylation.