Evaluation of periapical lesion healing by correction of gray values

The purpose of this study was to compare two methods for evaluating periapical healing in humans: the periapical index (PAI) and a gray value correction method. Fifty human teeth with a periapical lesion were endodontically treated. Radiographs, with a special aluminum device, were taken postoperatively, after 3 months and after 6 months. The PAI was recorded at each period of time, and a Kruskall and Wallis test was performed to compare the three groups. After scanning, the size of the lesion and its gray value were recorded. The aluminum device allowed the gray values to be equalized. An analysis of variance followed by a Duncan test was performed to compare the three groups. The teeth that showed no sign of healing according to the PAI were separately analyzed by an analysis of variance and a Duncan test. The PAI (n = 50) showed signs of periapical healing over time (p < 0.01). The analysis of variance, based on gray value evaluation (n = 50), also showed signs of periapical healing over time (p < 0.002). The analysis of variance of teeth with the same PAI over time (n = 15 at 3 months, and n = 5 at 6 months), based on gray value evaluation showed statistically significant differences among the 3 groups (p < 0.02). These results show that the gray level correction method is powerful and may reduce the risks of false negative responses during assessment of treatment results or epidemiological studies.     

Enhancing and diminishing gene function in human embryonic stem cells

It is widely recognized that gain- and loss-of-function approaches are essential for understanding the functions of specific genes, and such approaches would be particularly valuable in studies involving human embryonic stem (hES) cells. We describe a simple and efficient approach using lipofection to transfect hES cells, which enabled us to generate hES cell lines expressing naturally fluorescent green or red proteins without affecting cell pluripotency. We used these cell lines to establish a means of diminishing gene function using small interfering (si)RNAs, which were effective at knocking down gene expression in hES cells. We then demonstrated that stable expression of siRNA could knock down the expression of endogenous genes. Application of these gain- and loss-of-function approaches should have widespread use, not only in revealing the developmental roles of specific human genes, but also for their utility in modulating differentiation.     

Impact of one year of shift work on cardiovascular disease risk factors

The purpose of the study was to investigate whether the reported increased cardiovascular disease risk in shift workers could be explained by changes in cardiovascular risk factors. In a cohort of 239 shift and 157 daytime workers, 1-year changes in biological and lifestyle cardiovascular risk factors were monitored between the start of a new job and 1 year later. Both body mass index and low-density lipoprotein/high-density lipoprotein cholesterol ratio decreased significantly in shift workers compared with daytime workers (body mass index change: -0.31 and +0.13 kg/m; low-density lipoprotein/high-density lipoprotein ratio change: -0.33 and -0.13 respectively). Cigarettes smoked per day increased significantly in shift compared with daytime workers (+1.42 and -1.03, respectively). Therefore, only for smoking, an unfavorable change was observed. This may explain, at most, only a part of the excess cardiovascular disease risk reported in shift workers.     

Roles of unsaturated fatty acids (especially omega-3 fatty acids) in the brain at various ages and during ageing

Among various organs, in the brain, the fatty acids most extensively studied are omega-3 fatty acids. Alpha-linolenic acid (18:3omega3) deficiency alters the structure and function of membranes and induces minor cerebral dysfunctions, as demonstrated in animal models and subsequently in human infants. Even though the brain is materially an organ like any other, that is to say elaborated from substances present in the diet (sometimes exclusively), for long it was not accepted that food can have an influence on brain structure, and thus on its function. Lipids, and especially omega-3 fatty acids, provided the first coherent experimental demonstration of the effect of diet (nutrients) on the structure and function of the brain. In fact the brain, after adipose tissue, is the organ richest in lipids, whose only role is to participate in membrane structure. First it was shown that the differentiation and functioning of cultured brain cells requires not only alpha-linolenic acid (the major component of the omega-3, omega3 family), but also the very long omega-3 and omega-6 carbon chains (1). It was then demonstrated that alpha-linolenic acid deficiency alters the course of brain development, perturbs the composition and physicochemical properties of brain cell membranes, neurones, oligodendrocytes, and astrocytes (2). This leads to physicochemical modifications, induces biochemical and physiological perturbations, and results in neurosensory and behavioural upset (3). Consequently, the nature of polyunsaturated fatty acids (in particular omega-3) present in formula milks for infants (premature and term) conditions the visual and cerebral abilities, including intellectual. Moreover, dietary omega-3 fatty acids are certainly involved in the prevention of some aspects of cardiovascular disease (including at the level of cerebral vascularization), and in some neuropsychiatric disorders, particularly depression, as well as in dementia, notably Alzheimer's disease. Recent results have shown that dietary alpha-linolenic acid deficiency induces more marked abnormalities in certain cerebral structures than in others, as the frontal cortex and pituitary gland are more severely affected. These selective lesions are accompanied by behavioural disorders more particularly affecting certain tests (habituation, adaptation to new situations). Biochemical and behavioural abnormalities are partially reversed by a dietary phospholipid supplement, especially omega-3-rich egg yolk extracts or pig brain. A dose-effect study showed that animal phospholipids are more effective than plant phospholipids to reverse the consequences of alpha-linolenic acid deficiency, partly because they provide very long preformed chains. Alpha-linolenic acid deficiency decreases the perception of pleasure, by slightly altering the efficacy of sensory organs and by affecting certain cerebral structures. Age-related impairment of hearing, vision and smell is due to both decreased efficacy of the parts of the brain concerned and disorders of sensory receptors, particularly of the inner ear or retina. For example, a given level of perception of a sweet taste requires a larger quantity of sugar in subjects with alpha-linolenic acid deficiency. In view of occidental eating habits, as omega-6 fatty acid deficiency has never been observed, its impact on the brain has not been studied. In contrast, omega-9 fatty acid deficiency, specifically oleic acid deficiency, induces a reduction of this fatty acid in many tissues, except the brain (but the sciatic nerve is affected). This fatty acid is therefore not synthesized in sufficient quantities, at least during pregnancy-lactation, implying a need for dietary intake. It must be remembered that organization of the neurons is almost complete several weeks before birth, and that these neurons remain for the subject's life time. Consequently, any disturbance of these neurons, an alteration of their connections, and impaired turnover of their constituents at any stage of life, will tend to accelerate ageing. The enzymatic activities of sytivities of synthesis of long-chain polyunsaturated fatty acids from linoleic and alpha-linolenic acids are very limited in the brain: this organ therefore depends on an exogenous supply. Consequently, fatty acids that are essential for the brain are arachidonic acid and cervonic acid, derived from the diet, unless they are synthesized by the liver from linoleic acid and alpha-linolenic acid. The age-related reduction of hepatic desaturase activities (which participate in the synthesis of long chains, together with elongases) can impair turnover of cerebral membranes. In many structures, especially in the frontal cortex, a reduction of cervonic and arachidonic acids is observed during ageing, predominantly associated with a reduction of phosphatidylethanolamines (mainly in the form of plasmalogens). Peroxisomal oxidation of polyunsaturated fatty acids decreases in the brain during ageing, participating in decreased turnover of membrane fatty acids, which are also less effectively protected against peroxidation by free radicals.     

Distribution of the mRNAs encoding the thyrotropin-releasing hormone (TRH) precursor and three TRH receptors in the brain and pituitary of Xenopus laevis: effect of background color adaptation on TRH and TRH receptor gene expression

In amphibians, thyrotropin-releasing hormone (TRH) is a potent stimulator of alpha-melanotropin (alpha-MSH) secretion, so TRH plays a major role in the neuroendocrine regulation of skin-color adaptation. We have recently cloned a third type of TRH receptor in Xenopus laevis (xTRHR3) that has not yet been characterized in any other vertebrate species. In the present study, we have examined the distribution of the mRNAs encoding proTRH and the three receptor subtypes (xTRHR1, xTRHR2, and xTRHR3) in the frog CNS and pituitary, and we have investigated the effect of background color adaptation on the expression of these mRNAs. A good correlation was generally observed between the expression patterns of proTRH and xTRHR mRNAs. xTRHRs, including the novel receptor subtype xTRHR3, were widely expressed in the telencephalon and diencephalon, where two or even three xTRHR mRNAs were often simultaneously observed within the same brain structures. In the pituitary, xTRHR2 was expressed selectively in the distal lobe, and xTRHR3 was found exclusively in the intermediate lobe. Adaptation of frog skin to background illumination had no effect on the expression of proTRH and xTRHRs in the brain. In contrast, adaptation of the animals to a white background provoked an 18-fold increase in xTRHR3 mRNA concentration in the intermediate lobe of the pituitary. These data demonstrate that, in amphibians, the effect of TRH on alpha-MSH secretion is mediated through the novel receptor subtype xTRHR3.     

Leiomyoma remaining after vaginal hysterectomy for symptomatic leiomyomas. A case report

BACKGROUND: A remaining leiomyoma, an uncommon postoperative complication of vaginal hysterectomy for symptomatic leiomyomas, occurred. CASE: A second vaginal operation for a remaining leiomyoma was necessary 1 month after a vaginal hysterectomy for a myomatous uterus. CONCLUSION: Checking the pelvic cavity during hysterectomy may avoid this complication.     

Hemorrhage risk during operative hysteroscopy

BACKGROUND: To evaluate the risk of hemorrhage during hysteroscopic surgery. METHODS: Cases of hemorrhage during hysteroscopic surgery were assessed in a single center, observational, prospective study conducted from 1990 to 2000, including 2116 surgical hysteroscopies. Risk of hemorrhage was evaluated according to the hysteroscopic procedure. The management of this complication was also noted. RESULTS: Thirteen cases (0.61%) were reported. In six cases, hemorrhage stopped spontaneously. For six patients, a Foley (no. 10) probe was introduced into the uterine cavity and inflated for 24 h to stop hemorrhage. For one patient, immediately from the start of the procedure, the uterine arteries were ligatured through the vaginal route in order to stop bleeding. Haemorrhage risk was higher during hysteroscopic adhesiolysis compared with endometrial ablation (Relative risk [RR] 5.22 (1.26-21.64); p = 0.02), polyp [RR 5.3 (1.04-27.09); p = 0.04], and fibroid resections [RR 6.55 (1.58-27.17); p = 0.01]. Haemorrhage risk was however, comparable for endometrial ablation, uterus septa section, polyp, and fibroid resections (p = 0.92). CONCLUSIONS: Hemorrhage risk is higher during synechiolysis compared with other procedures. An inflated Foley probe may be an efficient means of stopping hemorrhage.     

Job mobility,its determinants,and its effects: longitudinal data from the Maastricht Cohort Study

This prospective study of 12,140 employees examined the effects of work characteristics and situational, psychological, and health aspects on job mobility. Before job change, the mobility group reported significantly more conflicts with the supervisor, higher physical and emotional strain, higher degree of job insecurity, lower job satisfaction, and lower degree of commitment compared with employees who did not change jobs. After job change, the mobility group reported improved autonomy, task diversity, decreased occurrence of conflicts with the supervisor, decreased physical and emotional strain, and improved training possibilities and job security than before the change. Changing jobs had a positive effect on employees with respect to job perception and job satisfaction and led to reduced fatigue and need for recovery.     

Neuropeptide Y inhibits the biosynthesis of sulfated neurosteroids in the hypothalamus through activation of Y(1) receptors

We have recently shown that hydroxysteroid sulfotransferase (HST), the enzyme responsible for the biosynthesis of pregnenolone sulfate (Delta(5)PS) and dehydroepiandrosterone sulfate (DHEAS), is expressed in neurons located in the anterior preoptic area and the dorsal magnocellular nucleus of the frog diencephalon. As these two nuclei are richly innervated by NPY-immunoreactive fibers, we investigated the possible implication of NPY in the control of Delta(5)PS and DHEAS biosynthesis. Double labeling of frog brain sections revealed that 42% of the HST-immunoreactive perikarya in the diencephalon were contacted by NPY-containing fibers. In situ hybridization studies showed that Y(1) and Y(5) receptor mRNAs are expressed in the anterior preoptic area and the dorsal magnocellular nucleus. Pulse-chase experiments with (35)S-labeled 3'-phosphoadenosine 5'-phosphosulfate as a sulfate donor demonstrated that frog NPY (fNPY) inhibited the conversion of [(3)H]Delta(5)P and [(3)H]dehydroepiandrosterone ([(3)H]DHEA) into [(3)H,(35)S]Delta(5)PS and [(3)H,(35)S]DHEAS by diencephalic explants. The inhibitory effect of fNPY on Delta(5)PS and DHEAS formation was mimicked by (pPYY) and [Leu(31),Pro(34)]pNPY, which is an agonist for non-Y(2) receptors in mammals, and was completely suppressed by the Y(1) receptor antagonist BIBP3226. Conversely, the Y(2) receptor agonist pNPY-(13-36) and the Y(5) receptor agonist [D-Trp(32)]pNPY did not significantly modify the biosynthesis of [(3)H,(35)S]Delta(5)PS and [(3)H,(35)S]DHEAS. The present study provides the first evidence for the innervation of neurosteroid-producing neurons by NPY fibers. Our data also demonstrate that NPY, acting via Y(1) receptors, exerts an inhibitory effect on the biosynthesis of sulfated neurosteroids.