Reduced intracellular oxidative metabolism promotes firm adhesion of human polymorphonuclear leukocytes to vascular endothelium under flow conditions

The interaction of polymorphonuclear leukocytes (PMN) with the vascular endothelium and their subsequent extravasation to the tissues is a key step during different physiological and pathological processes. In certain of these pathologies the oxygen tension becomes very low, leading to reduced cellular oxidative status. To evaluate the effect of lowering the intracellular redox status in the interaction of PMN with the endothelium, exposure to hypoxic conditions as well as treatment with different antioxidant agents was carried out. PMN exposure to hypoxia enhanced beta2 integrin-dependent adhesion to intercellular adhesion molecule-1-coated surfaces, concomitant with a decrease in the intracellular redox status of the cell. As occurs with hypoxia, treatment with antioxidants produced a decrease in the oxidation state of PMN. These agents enhanced adhesion of PMN to human umbilical vein endothelial cells stimulated with tumor necrosis factor-alpha (TNF-alpha), and this effect was also mediated by beta2 integrins LFA-1 and Mac-1. Adhesion studies under defined laminar flow conditions showed that the antioxidant treatment induced an enhanced adhesion mediated by beta2 integrins with a decrease in the fraction of PMN rolling on TNF-alpha-activated endothelial cells. The up-regulated PMN adhesion was correlated to an increase in the expression and activation of integrin Mac-1, without loss of L-selectin surface expression. Altogether, these results demonstrate that a reduction in the intracellular oxidative state produces an enhanced beta2 integrin-dependent adhesion of PMN to stimulated endothelial cells under conditions of flow.     

Systematic screening for fragile X syndrome in a cohort of 574 mentally retarded children

The Sense of Coherence Scale is used frequently world-wide and is thought to be appropriate to any population. The purpose of this study was to highlight some of the potential limitations of the scale. Fifteen members of the Pentecostal Movement described several difficulties in completing the scale, especially items measuring manageability and comprehensibility. The following three statements indicate the nature of their interpretation of the items and the ambiguity of their answers as they argued that: (1) the concept of 'I' was interpreted as 'I and God', (2) it is not necessary to understand everything in life, because it is enough that God understands, and (3) life is meaningful in itself because of the salvation. According to this interpretation of the items, every proposed answer could be suitable and consequently, the scores can readily be misconstrued. Many of the respondents proposed additions or changes in the wording to make the scale more suitable. The strong ego-centred items seem to be inappropriate for the participants in this study and other populations might also be confronted with similar difficulties.     

Choline kinase inhibitors as a novel approach for antiproliferative drug design

Recent progress in deciphering the molecular basis of carcinogenesis is of utmost importance to the development of new anticancer strategies. To this end, it is essential to understand the regulation of both normal cell proliferation and its alterations in cancer cells. We have previously demonstrated that in ras-transformed cells there is an increased level of phosphorylcholine (PCho) resulting from a constitutive activation on choiline kinase (ChoK). The importance of ChoK for the regulation of cell proliferation has also been proposed since an inhibitor for this enzyme, hemicholinium-3 (HC-3), drastically reduces entry into the S phase after stimulation with growth factors. Here we report the synthesis of several new compounds which are highly specific inhibitors for ChoK, with up to 1000-fold or 600-fold increased inhibitory activity, compared to HC-3 under ex vivo or in vitro conditions respectively. These novel compounds also drastically reduce entry into the S phase after stimulation with specific growth factors. A more profound inhibition of cell proliferation was observed in ras-, src- and mos-transformed cells in the presence of ChoK inhibitors, compared to their parental, untransformed NIH3T3 cells. By contrast, this effect was not observed in fos-transformed cells. While ras, src and mos transformation is associated with elevated levels of ChoK activity, fos-induced transformation does not affect ChoK activity. The inhibitory effect on proliferation of the new compounds correlates with their ability to inhibit the production of phosphorylcholine in whole cells, a proposed novel second messenger for cell proliferation. These results strongly support a critical role of choline kinase in the regulation of cell growth and makes this enzyme a novel target for the design of new antiproliferative and anticancer drugs.     

Evaluation of mental retardation: recommendations of a Consensus Conference: American College of Medical Genetics

A Consensus Conference utilizing available literature and expert opinion sponsored by the American College of Medical Genetics in October 1995 evaluated the rational approach to the individual with mental retardation. Although no uniform protocol replaces individual clinician judgement, the consensus recommendations were as follows: 1. The individual with mental retardation, the family, and medical care providers benefit from a focused clinical and laboratory evaluation aimed at establishing causation and in providing counseling, prognosis, recurrence risks, and guidelines for management. 2. Essential elements of the evaluation include a three-generation pedigree: pre-, peri-, and post-natal history, complete physical examination focused on the presence of minor anomalies, neurologic examination, and assessment of the behavioral phenotype. 3. Selective laboratory testing should, in most patients, include a banded karyotype. Fragile X testing should be strongly considered in both males and females with unexplained mental retardation, especially in the presence of a positive family history, a consistent physical and behavioral phenotype and absence of major structural abnormalities. Metabolic testing should be initialed in the presence of suggestive clinical and physical findings. Neuroimaging should be considered in patients without a known diagnosis especially in the presence of neurologic symptoms, cranial contour abnormalities, microcephaly, or macrocephaly. In most situations MRI is the testing modality of choice. 4. Sequential evaluation of the patient, occasionally over several years, is often necessary for diagnosis, allowing for delineation of the physical and behavioral phenotype, a logical approach to ancillary testing and appropriate prognostic and reproductive counseling.     

Oculocerebral dysgenesis in the linear nevus sebaceous syndrome

PURPOSE: The authors document the association of peripapillary staphyloma and an atypical variant of hemimegalencephaly with the linear nevus sebaceous syndrome. BACKGROUND: Linear nevus sebaceous syndrome is an uncommon neurocutaneous disorder that has a propensity to involve the eyes. METHODS: Clinical, histopathologic, and neuroimaging findings are examined in a child with linear nevus sebaceous syndrome. RESULTS: In addition to bilateral peripapillary staphylomas, ophthalmologic abnormalities included a corneal dermoid, a complex conjunctival choristoma, macular hypoplasia, and optic nerve hypoplasia with contralateral optic atrophy. Magnetic resonance imaging disclosed a rare form of hemimegalencephaly characterized by hypoplasia of an optic radiation within the enlarged, dysgenetic cerebral hemisphere. CONCLUSION: The spectrum of oculocerebral dysgenesis in the linear nevus sebaceous syndrome can be expanded to include peripapillary staphyloma and atypical hemimegalencephaly with hypoplasia of an optic radiation.     

Further studies on the immunopathology of atopic keratoconjunctivitis using flow cytometry

Atopic keratoconjunctivitis (AKC) is an ocular manifestation of systemic hypersensitivity. Although the pathogenesis of AKC is not fully understood, some previous data suggest that a decrease in numbers of suppressor T lymphocyte (Ts) and increase of Th, especially Th2 (the second subgroup of helper T lymphocyte), at the ocular surface may play an important role in the occurrence of the disease. In this study, the percentages of naive-Th (CD4/45RA+) and memory-Th (CD4/29+) cells, and the Th/Ts and memory-Th cells/naive-Th cells ratios were measured in the blood and tear samples of patients with AKC, atopic patients without ocular involvement and normal volunteers, using flow cytometry. Groups were compared using the Mann-Whitney U test. We found that patients with AKC had significantly higher memory-Th cell concentration, and Th/Ts and memory-Th cells/naive-Th cell ratios both in the tear and blood samples compared to normal subjects. While no significant difference existed between the tear samples of the atopic patients without ocular involvement and normal volunteers with respect to the above values, atopic patients had higher percentages of memory-Th cells and higher Th/Ts and memory-Th cells/naive-Th ratios in their blood than normal subjects. The percentages of memory-Th cells, and the Th/Ts and memory-Th cells/naive-Th cell ratios in the tear samples of AKC patients were also found to be higher than that of the atopic patients without ocular involvement, but no significant difference was present between the blood samples of these groups. The percentages of naive-Th cells did not show any significant difference between groups either in tear or blood samples. Since the mean memory-Th cells/naive-Th1 cells ratio in the tear samples of the patients with AKC was higher than in their blood samples, we propose that the localized accumulation of memory-Th2 cells, in addition to the increase of Th/Ts ratios in the external eye may cause AKC in atopic individuals.     

Yeast pseudohyphal growth is regulated by GPA2, a G protein alpha homolog

Pseudohyphal differentiation, a filamentous growth form of the budding yeast Saccharomyces cerevisiae, is induced by nitrogen starvation. The mechanisms by which nitrogen limitation regulates this process are currently unknown. We have found that GPA2, one of the two heterotrimeric G protein alpha subunit homologs in yeast, regulates pseudohyphal differentiation. Deltagpa2/Deltagpa2 mutant strains have a defect in pseudohyphal growth. In contrast, a constitutively active allele of GPA2 stimulates filamentation, even on nitrogen-rich media. Moreover, a dominant negative GPA2 allele inhibits filamentation of wild-type strains. Several findings, including epistasis analysis and reporter gene studies, indicate that GPA2 does not regulate the MAP kinase cascade known to regulate filamentous growth. Previous studies have implicated GPA2 in the control of intracellular cAMP levels; we find that expression of the dominant RAS2(Gly19Val) mutant or exogenous cAMP suppresses the Deltagpa2 pseudohyphal defect. cAMP also stimulates filamentation in strains lacking the cAMP phosphodiesterase PDE2, even in the absence of nitrogen starvation. Our findings suggest that GPA2 is an element of the nitrogen sensing machinery that regulates pseudohyphal differentiation by modulating cAMP levels.     

Severe and early alteration of action potential during acute cardiac rejection in rats

INTRODUCTION: Alteration of cardiac action potential and its adaptation to heart rate could contribute to cardiac dysfunction and arrhythmias during acute cardiac rejection. METHODS AND RESULTS: Heterotopic heart transplantation was performed in allogeneic and syngeneic rats in which the action potentials of right and left ventricles were measured at 1, 2.5, 3.3, and 5.7 Hz successively using standard microelectrode techniques and compared with nontransplanted hearts. For each frequency, we measured action potential amplitude, action potential duration, transmembrane resting potential, and Vmax. In the right ventricle, at 1 Hz in the presence of rejection (n = 40), a significant increase was observed in action potential duration at 20%, 50%, and 70% repolarization (82.5%, 75.6%, and 70.8%, respectively) and in action potential amplitude (+17.9 mV), and the resting potential was decreased (-5.3 mV). A lack of adaptation of action potential duration to the driving frequency was observed in the rejecting heart group in contrast to controls (n = 20) and nonrejecting hearts (n = 13). Similar results were observed in the left ventricle and surprisingly in the native hearts (n = 11) of recipients with allografted rejecting hearts in the abdominal position. CONCLUSION: Action potential and its adaptation to the driving frequency is considerably altered during acute rejection. A humoral factor could contribute to cardiac dysfunction.     

Response of large and small vessels to alpha and beta adrenoceptor stimulation in heart failure: effect of angiotensin converting enzyme inhibition

Understanding sexual fantasies is important to the scientific study of human sexuality. A sexual fantasy refers to a private or covert experience in which the imagination of desirable sexual activity with a partner is sexually arousing to the individual. Prior sexual experiences of an individual appear to increase the incidence of sexual fantasies, as well as the variety of sexual themes in a fantasy, which permit a greater elaboration of the fantasy theme when compared to less sexually experienced individuals. The present study was an investigation of the factors or sexual themes that emerge in a college male population, as well as a comparison of college men with human samples obtained in other studies: a sample of men and women and a sample of sexually variant men. In this study, 116 male students, all of whom identified themselves as heterosexual, completed the Wilson Sex Fantasy Questionnaire (WSFQ). Results indicated that the present sample had significantly more exploratory, intimate, impersonal, and total sexual fantasies than sexual fantasies reported by female respondents in another study using the WSFQ and significantly more intimate, impersonal, and total sexual fantasizing when compared with a male sample in another study. The men in this study also evidenced less deviant areas of sexual fantasizing when compared with a group of sexually variant men in another study. A principal components analysis extracted four factors, which accounted for 45% of the total variance. The four sexual fantasy topic areas for the most part replicated prior findings by Wilson (1988) but are also more heterogeneous, indicating that male college students engage in a variety of sexual fantasies but seem to favor more intimate, less deviant or exploratory sexual themes that are in line with nonclinical samples and different from several clinical samples of sexually variant men.     

Neurotransmitters in cerebrospinal fluid reflect pathological activity

Reduced bone mineral density (BMD), termed diabetic osteopenia, has been reported in patients with insulin-dependent (Type 1) diabetes mellitus (IDDM). To examine BMD in long-term IDDM patients with normal kidney function, but with different degrees of urinary albumin excretion rate (UAER), compared to that of patients with elevated plasma creatinine, 36 IDDM male patients (mean duration 27 years) were subdivided according to UAER (<30, 30-300, >300, >300 mg 24 h(-1) and plasma creatinine 0.120-0.350 mmol l(-1)) and 15 controls were recruited. BMD was measured by dual energy X-ray absorptiometry and UAER by enzyme linked immunosorbent assay. BMD was normal in IDDM patients with normal UAER and reduced in the femoral neck, the trochanter major, and the Wards triangle in patients with increased UAER (p < 0.01, p < 0.05, p < 0.02). BMD correlated to creatinine clearance in both cortical and cancellous bone sites (p < 0.001, p < 0.0001), and inversely to the levels of plasma PTH (p < 0.0005). We conclude that BMD is normal in long-term IDDM male patients with normal kidney function and normal UAER and reduced in patients with increased UAER. Diabetic osteopenia seems to be a progressive phenomenon related to diabetic nephropathy and associated with the decrease in creatinine clearance and with the resulting rise in plasma PTH.