Suicide in deaf populations: a literature review

Background  

Studies have found that deaf individuals have higher rates of psychiatric disorder than those who are hearing, while at the same time encountering difficulties in accessing mental health services. These factors might increase the risk of suicide. However, the burden of suicidal behaviour in deaf people is currently unknown.     

Epidemiology of abdominal symptoms in a random population: Prevalence,incidence, and natural history

The study presents results from a five-year follow-up on abdominal symptoms in an age and sex stratified random sample of 4,581 Danes. Abdominal pain occurred significantly more often among women (prevalence: 49%, incidence: 21%) compared to men (prevalence: 38%, incidence: 15%). Five years later the pain had disappeared in 43% of the men and 31% of the women (p=0.003). Distension, borborygmi, and altering consistency of stools occurred with a prevalence of approximately 50% and an incidence of approximately 30%, significantly more often among women compared to men. Five years later these symptoms had disappeared in about 20%. Prevalence of both heartburn and acid regurgitation were significantly higher among men (38%) than women (30%), whereas no sex difference was observed regarding incidence of these symptoms (16%). Approximately 30% of subjects who had experienced heartburn or acid regurgitation did not do so five years later. In conclusion, abdominal symptoms occur frequently and recurrently in the general population. This information is of importance to doctors when they evaluate patients with abdominal complaints, but no obvious organic etiology.     

Heterotopic transplantation of cryopreserved tracheae in a rat model.

INTRODUCTION: The successful use of cryopreserved tracheal allografts in canine models suggests their use in humans. The grade of genetic difference, the mechanism of revascularisation and the method of cryopreservation are not clearly defined. The purpose of our study was to investigate the rejection of tracheal transplants in a standardised heterotopic rat model using different forms of cryopreservation. METHODS: Tracheae from Brown Norway rats were implanted into the omentum from Brown Norway rats or Lewis rats. We transplanted fresh isografts or allografts and pretreated isografts or allografts. Cryopreservation was performed in a medium containing 10% dimethyl sulphoxide at -80 degrees C for 28 days (I) or -196 degrees C for 84 days (II) or without medium at -80 degrees C for 28 days (III). The transplants were excised after 7 and 21 days, respectively. RESULTS: Histological examinations revealed normal structure and function of isografts after 21 days. In the cryopreserved isograft, the epithelium had disappeared and the tracheal lumen was partially obstructed by a non-compact fibrous tissue. In the fresh allografts, the epithelium was replaced by aggressive fibrous tissue, infiltrating the membranous part of the trachea and occluding the tracheal lumen. The cartilage was vital without any sign of rejection. In the cryopreserved allografts, the tracheal lumen was obstructed by dense fibrous tissue with an inflammatory reaction. The cartilage of cryopreserved allografts (II) and (III) had lost the nuclei corresponding to non-vital tissue. Only in the cryopreserved allografts (I) did we find nodular regeneration at the edges of the cartilaginous bow. CONCLUSIONS: The heterotopic transplantation model allows the study of the mechanisms leading to tracheal obstruction. Cryopreservation was found to have no clear advantage in reducing transplant immunogenicity. Cryopreservation leads to significant damage to the cartilage, the intensity of which is dependent on the mode of cryopreservation.     

Gene transfer experiments imply instructive role of major histocompatibility complex class I molecules in cellular peptide processing.

DBA/2-derived mouse tumor cells were transfected with the H-2 Kb gene. Naturally processed minor histocompatibility (H) peptides were extracted from both transfected and non-transfected cells by acid elution, and were separated by high-performance liquid chromatography. Kb-restricted minor H epitopes corresponding to H-4b and mapki, both encoded by non-major histocompatibility complex genes of DBA/2, were readily detected by the respective cytotoxic T lymphocyte in peptides extracted from Kb-transfected, but not from non-transfected or Db-transfected cells. Titration experiments indicated at least 3000-fold less copies of correctly processed Kb-restricted epitopes in cells without Kb as compared to cells with Kb. Since we estimate the copy number of Kb-restricted H-4b epitopes in Kb-expressing transfectants to be less than 1000 per cell, the pool size of H-4b epitopes correctly processed in the absence of Kb should be less than 1/3 copy per cell.     

Prospective study of bacterial and viral contamination of exercise equipment.

OBJECTIVE: Transmission of bacterial and viral pathogens is known to occur by hand contact with fomites. Exercise equipment in public facilities may serve as such fomites. It is not known whether equipment disinfection might reduce microorganism colonization. We performed studies to address these issues. DESIGN: Observational study of bacterial and viral culture results from hand-contact surfaces of exercise equipment, pre-exercise and postexercise; prospective study of viral culture results before and after intervention with disinfection solution. SETTING: Two fitness centers in a military community. INTERVENTION: One week trial of twice-a-day equipment disinfection. MAIN OUTCOME MEASURES: Type and number of bacteria and type of viruses present on equipment before and after exercise; prevalence of viral culture positivity on equipment before and after intervention. RESULTS: Bacterial cultures of body contact surfaces on equipment revealed benign bacterial species (coagulase-negative staphylococci, diphtheroids, and so forth) but no pathogenic bacteria whether obtained pre-exercise or postexercise, or whether from aerobic versus weight training equipment. Viral cultures revealed the presence of viruses (generally rhinoviruses) on 63 of 100 (63%) hand-contact surfaces of equipment. Weight equipment was significantly more often contaminated than aerobic equipment (73% vs. 51%; P = 0.026). Disinfection of equipment did not lower the prevalence of virus isolation (48% positive before cleaning; 86% positive after cleaning). CONCLUSIONS: There is little risk of exposure to pathogenic bacteria on exercise equipment. Such equipment may commonly serve as fomites for the transmission of viruses. These data do not suggest that disinfection of exercise equipment will offer significant protective effects against virus exposure.     

Dopamine transporters, D2 receptors, and glucose metabolism in corticobasal degeneration.

Alterations in presynaptic and postsynaptic dopaminergic system and cerebral glucose metabolism in corticobasal degeneration (CBD) were assessed to evaluate the potential usefulness of different imaging methods for CBD. (123)I-FP-CIT/(123)I-beta-CIT SPECT and (123)I-IBZM SPECT as well as (18)F-FDG PET were performed in eight CBD patients. Decreased presynaptic dopamine transporter binding was found in all CBD patients while D2 receptor binding was reduced in only one patient. (18)F-FDG PET displayed a contralateral hypometabolism in cortical and subcortical areas in seven out of eight patients. Our results demonstrate that glucose metabolism and DAT are reduced, while D2 receptors may be frequently preserved in CBD.     

Intense vasoconstriction in response to aspirate from stented saphenous vein aortocoronary bypass grafts.

OBJECTIVES: We sought to identify soluble vasoconstrictor substances that are released during stent implantation into saphenous vein aortocoronary bypass grafts. BACKGROUND: Atherosclerotic saphenous vein aortocoronary bypass grafts are particularly vulnerable to plaque rupture. Protection devices prevent particulate debris from being embolized. Additional soluble vasoconstrictor substances possibly also contribute to impaired microvascular perfusion. METHODS: Peripheral venous blood (VB) and aspirate (AS) were obtained from 14 patients with a significant stenosis in a saphenous vein graft during stent implantation under protection with a distal balloon occlusion device. In five additional patients, arterial blood (AB) was also taken distal to the stented lesion before intervention. Vasomotor substances in VB, AB, and AS plasma were identified in a bioassay of rat mesenteric arteries with intact (+E) and denuded endothelium (-E). Vasoconstriction was normalized to that induced by potassium chloride depolarization (100%). RESULTS: Venous blood, AB, and AS plasma induced maximum vasoconstriction within six minutes. The AS plasma induced a vasoconstriction of 138 +/- 13% (-E) and 87 +/- 14% (+E); VB, of 70 +/- 14% (-E) and 23 +/- 4% (+E); and AB plasma obtained before intervention, of 49 +/- 9% (-E) and 36 +/- 8% (+E). The vasoconstrictor potency of AS plasma in endothelium-denuded vessels was related to the severity of anginal symptoms, angiographic stenosis severity, plaque volume, and plaque burden as determined by intravascular ultrasound. The AS plasma-induced vasoconstriction was largely attenuated by combined serotonin/5-hydroxytryptamine (5-HT)(2A/2C)- and 5-HT(1A/1B)-receptor blockade and eliminated by additional thromboxane A2 thromboxane-prostanoid (TP)-receptor blockade. CONCLUSIONS: Stent implantation releases, apart from and in addition to particulate debris, soluble vasoconstrictor substances that possibly contribute to impaired microvascular perfusion.     

Cholesterol-sensing receptors, liver X receptor alpha and beta, have novel and distinct roles in osteoclast differentiation and activation.

The liver X receptor (alpha,beta) is responsible for regulating cholesterol homeostasis in cells. However, our studies using the LXRalpha-/-, LXRbeta-/-, and LXRalpha-/-beta-/- mice show that both LXRalpha and beta are also important for bone turnover, mainly by regulating osteoclast differentiation/activity. Introduction: The liver X receptors (alpha,beta) are primarily responsible for regulating cholesterol homeostasis within cells and the whole body. However, as recent studies show that the role for this receptor is expanding, we studied whether the LXRs could be implicated in bone homeostasis and development. MATERIALS AND METHODS: pQCT was performed on both male and female LXRalpha-/-, LXRbeta-/-, LXRalpha-/-beta-/-, and WT mice at 4 months and 1 year of age. Four-month-old female mice were additionally analyzed with reference to qPCR, immunohistochemistry, histomorphometry, transmission electron microscopy, and serum bone turnover markers. RESULTS: At the mRNA level, LXRbeta was more highly expressed than LXRalpha in both whole long bones and differentiating osteoblast-like MC3T3-E1 and osteoclast-like RAW 264.7 cells. Four-month-old female LXRalpha-/- mice had a significant increase in BMD because of an increase in all cortical parameters. No difference was seen regarding trabecular BMD. Quantitative histomorphometry showed that these mice had significantly more endosteal osteoclasts in the cortical bone; however, these cells appeared less active than normal cells as suggested by a significant reduction in serum levels of cross-linked carboxyterminal telopeptides of type I collagen (CTX) and a reduction in bone TRACP activity. Conversely, the female LXRbeta-/- mice exhibited no change in BMD, presumably because a significant decline in the number of the trabecular osteoclasts was compensated for by an increase in the expression of the osteoclast markers cathepsin K and TRACP. These mice also had a significant decrease in serum CTX, suggesting decreased bone resorption; however, in addition presented with an increase in the expression of osteoblast associated genes, bone formation markers, and serum leptin levels. CONCLUSIONS: Our findings show that both LXRs influence cellular function within the bone, with LXRalpha having an impact on osteoclast activity, primarily in cortical bone, whereas LXRbeta modulates trabecular bone turnover.