Metabolic polymorphisms and the micronucleus frequency in buccal epithelium of adolescents living in an urban environment

Micronuclei and other biomarkers were evaluated in oral cells from 11- to 16-year-old girls living in a foster home in the central area of México City. Variables analyzed for possible association with these biomarkers include smoking habits, body mass index, metabolic polymorphisms for NAT1 and GSTM1 and whether the cells were obtained from the cheek or pharynx. The results indicated that individuals having the NAT1*10 homozygous genotype showed a significant increase in chromatin buds and binucleated cells. When the damage in the cheek was compared with damage in the pharynx, a significant increase in micronuclei and binucleated cells was found for the latter tissue in all the individuals analyzed.     

The role of recombination signal sequences in the preferential joining by deletion in DH-JH recombination and in the ordered rearrangement of the IgH locus

The bias favoring deletion over inversion in DH-JH rearrangement has been known for years, but the underlying mechanism has yet to be fully defined. It has been suggested that the ratio of deletion/inversion is determined by the combined effect of two factors: (i) the relative strengths of 5' and 3' recombination signal sequences (RSS) of a DH segment, and (ii) the efficiency with which the deletional product (one joint) forms relative to the inversional product (two joints). In this study, we analyzed for the first time the effect of factor 1 alone on the biased 3' RSS utilization in DH-JH joining by using deletional plasmids in an extrachromosomal substrate V(D)J recombination assay. It was found that the 3' RSS and associated coding end (12 bp) mediate recombination more efficiently than the 5' RSS/coding end DH-JH plasmids. These results demonstrate that the effect of the RSS/coding end alone can account, at least partially, for the predominant deletion in DH-JH recombination. The potential effect of the relative strength of RSS and associated coding end on the ordered rearrangement of DH-JH followed by VH to DH-JH was also assessed. When recombination frequencies of D-->J (3' DH to J3) were compared with frequencies of V-- >D (VHPJ14 to 3' DH or VHOX2 to 3' DH), it was found that V-->D joining was, if anything, more efficient than D-->J joining. Therefore, if all three segments were accessible, RSS/coding end effects would not contribute to the ordered rearrangement of the IgH locus.      

Is Tourette syndrome a cause of sudden infant death syndrome and childhood obstructive sleep apnea?

The cause of sudden infant death syndrome (SIDS) is unknown. Sleep-related impairment of respiratory control and arousal are postulated; hyperdopaminergic and hyposerotonergic dysfunction may contribute to events leading to infant apnea and SIDS. Psychosocial adversity and impulsive and compulsive behaviours characterize some families of SIDS victims. Tourette syndrome (TS) is a common hereditary neurobehavioral disorder characterized by the frequent presence of impulsive and compulsive behaviors. Sleep disorders are common and include sleep apnea and abnormal arousal. Hyperdopaminergic and hyposerotonergic abnormalities are postulated to contribute to the pathophyusiology of the disorder. The following is a report of the presence of incidents of infant apnea and SIDS in families in which TS was present. In an additional TS family, a child had obstructive sleep apnea syndrome (OSAS). Results of a preliminary survey suggest that TS gene carriers are at increased risk of life-threatening apneas of infancy and that the prevalence of SIDS in such families may be 2 to 5 times the prevalence in the general population. The presence in some pedigrees of sleep apnea in children and adults suggest that in some instances disorders of sleep-related ventilatory control and arousal occurring throughout the life-span share common pathophysiological mechanisms. © 1993 Wiley-Liss, Inc.     

Upper tibial corticocancellous flap anatomy study (19.2.93)

Summary A cortico-cancellous flap from the anterolateral aspect of the upper third of the tibia was presented. Sixty lower limbs of fresh cadavers were dissected. The vascular bundle includes the anterior tibial artery and its recurrent collateral branches and recurrent and muscllo periostal arteries. The flap is harvested with the interosseous membrane and can be used either free or pedicled. We used this flap for two patients suffering from pseudarthrosis. Long range clinical and radiological results are good.

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Le transfert osseux vascularisé tibial superieur

Résumé Les auteurs décrivent un transfert ostéo-periosté vascularisé, prélevé sur la face antéro-latérale de l'extremité supérieure du tibia. L'étude anatomique porte sur soixante membres inférieurs, conservés au froid. La vascularisation métaphysaire du transfert provient de la branche récurrente tibiale antérieure et de ses rameaux, la vascularisation diaphysaire étant issue des branches musculo-périostiées proximales. Le transfert vascularisé est prélevé avec la membrane interosseuse et peut être pediculé ou libre. L'expérience clinique porte sur deux cas de pseudarthroses multiopérées. Les résultats cliniques et radiologiques sont bons à long terme.

     

The use of laparoscopic ovarian electrocautery in preventing cancellation of in-vitro fertilization treatment cycles due to risk of ovarian hyperstimulation syndrome in women with polycystic ovaries

Fifty women with polycystic ovaries took part in a prospective randomized study. All women required treatment by in-vitro fertilization (IVF) for reasons other than anovulation. They had all previously undergone ovarian stimulation with gonadotrophin therapy which had failed to result in pregnancy or had been abandoned due to high risk of developing ovarian hyperstimulation syndrome (OHSS). Twenty-five women were treated by long-term pituitary desensitization followed by gonadotrophin therapy, oocyte retrieval and embryo transfer (group 1). Twenty-five women underwent laparoscopic ovarian electrocautery after pituitary desensitization followed by gonadotrophin therapy, oocyte retrieval and embryo transfer (group 2). A significantly higher number of women in group 1 had to have the treatment cycle abandoned due to impending or actual OHSS, determined by endocrine and clinical findings. In addition, the development of moderate or severe OHSS in completed cycles was higher in group 1. The pregnancy rate and miscarriage rates in the two treatment groups were similar. The authors propose that laparoscopic ovarian electrocautery is a potentially useful treatment for women who have previously had an IVF treatment cycle cancelled due to risk of OHSS or who have suffered OHSS in a previous treatment cycle.      

The salivary microbiota as a diagnostic indicator of oral cancer: A descriptive,non-randomized study of cancer-free and oral squamous cell carcinoma subjects

Background  

The purpose of the present investigation was to determine if the salivary counts of 40 common oral bacteria in subjects with an oral squamous cell carcinoma (OSCC) lesion would differ from those found in cancer-free (OSCC-free) controls.     

Potassium transport in epithelial cells isolated from small intestine of the chicken

The transport of potassium has been studied in epithelial cells isolated from chicken small intestine using⁸⁶Rb as a tracer for K⁺. (i) The uptake studies revealed that about 60% of the total K⁺ net flux is inhibited by ouabain and therefore mediated by the Na⁺–K⁺-ATPase. About 20% of the ouabain-insensitive K⁺ net influx was inhibited by furosemide, bumetanide and by either Na⁺ or Cl^– removal from the incubation solution, suggesting that a Na⁺/Cl^–/K⁺ cotransport system might be present in chicken enterocytes. (ii) The efflux of K⁺ was measured from cells preloaded with⁸⁶Rb. K⁺ efflux was inhibited by Ba²⁺, quinine and verapamil; it was stimulated by A23187, and it was unaffected by 3,4-diaminopyridine. Apamin, that has no effect on basal rates of K⁺ efflux, abolished the effect of A23187. These findings suggest that K⁺ efflux appears to occur through Ca²⁺-activated K⁺ channels.     

Identification of MEN1 gene mutations in sporadic carcinoid tumors of the lung

Lung carcinoids occur sporadically and rarely in association with multiple endocrine neoplasia type 1 (MEN1). There are no well defined genetic abnormalities known to occur in these tumors. We studied 11 sporadic lung carcinoids for loss of heterozygosity (LOH) at the locus of the MEN1 gene on chromosome 11q13, and for mutations of the MEN1 gene using dideoxy fingerprinting. Additionally, a lung carcinoid from a MEN1 patient was studied. In four of 11 (36%) sporadic tumors, both copies of the MEN1 gene were inactivated. All four tumors showed the presence of a MEN1 gene mutation and loss of the other allele. Observed mutations included a 1 bp insertion, a 1 bp deletion, a 13 bp deletion and a single nucleotide substitution affecting a donor splice site. Each mutation predicts truncation or potentially complete loss of menin. The remaining seven tumors showed neither the presence of a MEN1 gene mutation nor 11q13 LOH. The tumor from the MEN1 patient showed LOH at chromosome 11q13 and a complex germline MEN1 gene mutation. The data implicate the MEN1 gene in the pathogenesis of sporadic lung carcinoids, representing the first defined genetic alteration in these tumors.      

Localization of gamma-aminobutyric acid (GABA) in type 3 cells and demonstration of their source to F2 terminals in the cat lateral geniculate nucleus: a Golgi-electron-microscopic GABA-immunocytochemical study

Postembedding immunocytochemistry with a gamma-aminobutyric acid (GABA) antiserum was done on semithin sections of cat lateral geniculate nucleus (LGN) previously processed with the rapid-Golgi and gold-toning procedures, to determine which of the three main morphological types (1, 2,3) of neurons in the A-laminae show immunoreactivity and are, therefore, presumably GABAergic. Only type 3 cells were found to be GABA positive. These cells were characterized by small somata and few, scarcely branched dendrites bearing almost exclusively appendages with long slender stalks. Some of these cells have extensive filiform "axonlike" processes originating from different regions of dendrites and having appendages similar to those originating directly from dendrites. Many of these Golgi gold-toned impregnated dendritic appendages of type 3 cells were analyzed in the electron microscope and were identified as typical F2 terminals by their content of pleomorphic synaptic vesicles; by being postsynaptic to retinal (RLP), cortical (RSD), and perigeniculate (F1) terminals; and by being presynaptic to dendrites. In addition, since it was previously demonstrated that glutamic acid decarboxylase (GAD) and GABA-positive cells are not retrogradely labeled with horseradish peroxidase (HRP) from the visual cortex, the present results, by showing that GABA-positive cells have type 3 morphology, provide supporting evidence for the interneuronal nature of type 3 cells in cat LGN.