HLA-DR, DQ genotypes of celiac disease patients and healthy subjects from the West of Ireland

Celiac disease (CD) has one of the strongest class II HLA associations of any human illness. We used DNA-RFLP typing to study the class II HLA genotypes of celiac disease patients from the West of Ireland, the geographic area with the highest rate of celiac disease in the world. We confirmed the high frequency of HLA-DR3 in this population, and we were also able to demonstrate the additional risk of developing celiac disease imparted by HLA-DR7. This was done by clearly distinguishing DR7, DQ2 haplotypes from DR7, DQ9 haplotypes, and by "subtraction analysis" of haplotype frequencies. As reported in other populations, most of the patients without DR3 were heterozygous for DR7 and DR11 or 12 (DR5), or had DR4. We used PCR-RFLP and direct sequencing of amplified DNA to examine HLA-DR4 subtypes. The frequency of HLA-DR4 was markedly decreased in patients compared with controls (p=0.000001) and there was a significant alteration of DR4 subtypes of the patients compared with controls (p=0.0227). Moreover, all of the CD patients (5 of 5) with DR4 had a haplotype associated with the DQB1*0302 allele compared with only 11 of 23 control subjects with DR4. Our results in this population with exceptionally high risk of CD strongly support the DQ heterodimer hypothesis and suggest that the recently described sequence difference between the DQB1*02 alleles of DR3 and DR7 may contribute to a synergistic increased risk when these haplotypes are inherited together. In addition, our findings suggest a role for HLA-DQ in DR4-associated CD.     

Abnormal Digital Pressure Measurements in Diabetic Neuropathic Foot Ulceration

The diabetic neuropathic ulcer is typically slow to heal and recurrent. Macrovascular insufficiency is usually excluded as foot pulses are present and ankle:brachial pressure ratios are not decreased. These assessments cannot however exclude more distal vascular disease. Digital pressure measurements enable a reliable assessment of the distal peripheral vascular status to be made. The aim of this study was therefore to use toe pressures to assess the contribution of distal ischaemia in the pathogenesis of the neuropathic ulcer. Sixteen diabetic patients with recurrent neuropathic foot ulceration had their toe pressures compared to 10 neuropathic patients without a history of foot ulceration, 10 diabetic control subjects, and 11 normal subjects. Four non-diabetic patients with neuropathy and foot ulceration were also assessed. All subjects had ankle:brachial pressure indices ≧ 1. Toe pressure was assessed using laser Doppler flowmetry to record the return of skin blood flow. The toe:brachial pressure index (TBI) was then calculated. The diabetic patients with a history of recurrent neuropathic ulceration, had the lowest mean TBI, 0.63 ± 0.14 (SD), compared to the non-ulcerated diabetic neuropathy patients, the diabetic control subjects, and the normal subjects. 0.84 ± 0.11, 0.82 ± 0.1, and 0.81 ± 0.07, p < 0.01, respectively. Three of the four non-diabetic patients with neuropathic foot ulceration also had an abnormally low TBI. Reduced toe pressure measurements are thus found to be associated with neuropathic foot ulceration. The contribution of distal ischaemia in the pathogenesis of the diabetic neuropathic foot ulcer needs to be evaluated. One hundred and eight non-insulin-dependent diabetic patients who had been tested for autonomic dysfunction in 1984/85 were re-evaluated 5 years later. Autonomic function was assessed by means of four cardiovascular tests (heart rate variation during deep breathing and standing, and blood pressure variation after standing and sustained handgrip). Eighteen subjects were lost to follow-up; in the 90 patients who completed the study, both the deep breathing and the handgrip test significantly worsened (respectively from 13.7 ± 7.8 to 11.6 ± 6.3 beats min^?1 p < 0.01, and from 16.9 ± 8.2 to 12.7 ± 7.1 mmHg, p < 0.001), whereas both the 30:15 ratio and the variation of blood pressure on standing did not change. The impairment of a comprehensive evaluation score (from 2.5 ± 1.7 to 3.0 ± 1.5; p < 0.05) also confirmed the gradual deterioration of autonomic function over the study period.     

Feasibility analysis for medical services.

Feasibility analysis is an important aspect of business planning. A feasibility study is a study of the impacts of revenues, cost, and returns on a decision. It helps answer the questions of "What share of total sales can be attained?" "What revenues will be generated?" "What costs will be incurred?" "What will be the return on investment?" The discipline of going through a systematic approach to analyze market demand, cost requirements, and return on investment will improve business decisions by eliminating risk and increasing the possibility of successful ventures.     

"Worst case" aerosol testing parameters: I. Sodium chloride and dioctyl phthalate aerosol filter efficiency as a function of particle size and flow rate

The efficiency of filter media is dependent on the characteristics of the challenge aerosol and the filter's construction. Challenge aerosol parameters, such as particle size, density, shape, electrical charge, and flow rate, are influential in determining the filter's efficiency. In this regard, a so-called "worst case" set of conditions has been proposed for testing respirator filter efficiency in order to ensure wearer protection. Data collected on various types of filters (dust and mist; dust, fume, and mist; paint, lacquer, and enamel mist; and high efficiency) challenged with a worst case-type sodium chloride (NaCl) and dioctyl phthalate (DOP) aerosol are presented. The particle size of maximum penetration varies as a function of filter type and was less than 0.25-micron count mean diameter (CMD) in all cases. The count efficiency for high efficiency filters was greater than 99.97% at worst case testing conditions, but the worst case count efficiencies for dust and mist; dust, fume and mist; and paint, lacquer and enamel mist filters were not nearly as efficient as existing test methods indicate. Also, as the test flow rate is increased, the count efficiency decreases. Thus, respirator filters were found to conform to the prediction of single-fiber filtration theory.     

Reduced cortical noradrenergic neurotransmission is associated with increased neophobia and impaired spatial memory in aged rats

In the present study, young (5-month-old (mo)) and aged (24 mo) adult male Fischer-344 (F344) rats were assigned to experimental groups based upon their performance of a reference memory task in the Morris water maze and reactivity to a novel palatable taste in a gustatory neophobia task. Levels of norepinephrine (NE) and its metabolite 3-methoxy-4-hydroxy-phenylglycol (MHPG) were assayed via high performance liquid chromatography (HPLC) in brain regions associated with the locus coeruleus (LC)-hippocampus-cortex system and A1/A2-hypothalamic system. Binding of ligands specific for alpha-1, alpha-2, beta-1, and beta-2 receptors was assessed in hippocampus and cortex with receptor autoradiography. Impaired acquisition and retention of the water maze task and gustatory neophobia in aged rats was primarily associated with decreased NE activity in cingulate cortex (CC) as indicated by a significant reduction in the MHPG/NE ratio coupled with increased NE content. No significant changes in adrenergic receptor binding were detected in any region sampled. The results suggest that an aging-related reduction in cortical NE neurotransmission is associated with the expression of increased neophobia and deficits in spatial learning and memory performance occurring with advanced age in rats.     

Production of pemphigus antibodyin vitro and analysis of T-cell subsets

T cells from nine patients in the active stage of pemphigus vulgaris and five in the inactive stage of the disease were studied with Leu-1, Leu-2, and Leu-3 monoclonal antibodies. No significant differences were observed in the proportions of total T cells or T cells expressing either helper or suppressor phenotype in peripheral blood leukocytes of patients compared to normal subjects. Immunoregulatory mechanisms were functionally studied using an assay measuring total IgG synthesizedin vitro. Peripheral blood leukocytes were separated into T- and B-cell fractions and cultured in various combinations. In nine experiments, the T cells were irradiated prior to culturing with B cells to remove their suppressor function. No statistically significant differences were observed in the total IgG synthesized by B cells obtained from patients and normal subjects when cultured with untreated T cells or irradiated T cells obtained from patients or normal controls. These results indicated that there was no loss of suppressor-cell function or increased helper-cell function when assessed by measuring the total IgG synthesized. The addition of serum from pemphigus patients to peripheral blood leukocyte cultures of pemphigus patients and normal controls had no statistically significant effect on the synthesis of total protein or on the amount of Ig synthesized and secreted. Peripheral blood leukocytes from six untreated patients with pemphigus vulgaris were stimulatedin vitro with pokeweed mitogen (PWM) to produce immunoglobulin. The IgG produced selectively bound to the intercellular cement substance of the epidermis of patients' perilesional skin, normal human skin, and monkey esophagus. The IgG was biosynthetically labeled by culturing the leukocytes in medium supplemented with [³H]leucine, and the binding of the radiolabeled IgG was visualized by autoradiography. The IgG nature of the protein was demonstrated by precipitation withStaphylococcus protein A and removal with rabbit anti-human IgG antisera. Peripheral blood leukocytes obtained from normal volunteers and control patients did not produce this antibody. Our studies indicate that there was no general functional or phenotypic alteration of suppressor or helper T cells in the peripheral blood. The peripheral blood leukocytes of pemphigus patients under PWM stimulation can produce an anti-intercellular cement substance antibodyin vitro. These results indicate that the abnormality of immunoregulation which resulted in the production of a pathogenetic autoantibody in pemphigus is highly specific.     

Cyclin D1 overexpression in AIDS-related and classic Kaposi sarcoma.

The anatomic distribution and rate of progression vary significantly between acquired immunodeficiency syndrome (AIDS)-related Kaposi sarcoma (KS) and classic KS. The reasons are unclear, but cyclin D1 overexpression is associated with tumor progression in other malignancies. Cyclin D has an important regulatory role in the progression of cell cycle at the G1-S phase due to its effect in phosphorylating the retinoblastoma gene product. Forty-one paraffin-embedded surgical specimens (31 AIDS-related, 10 classic) were examined using streptavidin-biotin-peroxidase immunohistochemistry with monoclonal antibody to cyclin D1. A scoring system based on the intensity and extent of staining was used. The correlations among cyclin D1 expression and clinicopathologic parameters were statistically analyzed. Cyclin D1 overexpression was found in 29% (12/41) of all KS cases. There was a strong correlation between cyclin D1 overexpression and pathologic stage (0% in patch stage, 13% in plaque stage, 50% in nodular stage; P = 0.0017). Classic KS lesions had a higher incidence of cyclin D1 overexpression than AIDS-related lesions (70% vs 16%, P = 0.001). Cyclin D1 overexpression was detected in 78% of the classic nodular lesions and 31% of the AIDS-related nodular lesions (P = 0.03). On multivariate analysis, negative human immunodeficiency virus status (P = 0.001) and nodular lesions (P = 0.007) were strong predictors of cyclin D1 overexpression. Age, gender, recurrence of the tumor, multiplicity, and site of the lesions hold no statistically significant association with cyclin D1 expression on multivariate analysis. In summary, cyclin D1 overexpression was more prevalent in classic lesions and more advanced nodular stage. These findings raise the possibility of a different pathogenetic mechanism in the progression of AIDS-related KS and classic KS.     

The hemodynamics of oddball processing during single-tone and two-tone target detection tasks

Event-related potential (ERP) studies have shown that the neural systems engaged during performance of oddball tasks are sensitive to contextual manipulations, such as the number of stimulus classes. Some ERP components (i.e., N1) are modulated by the number of stimulus types, while others (i.e., P3) are not greatly affected. However, little is known about how these contextual manipulations affect the hemodynamics underlying oddball processing. The purpose of this study was to examine the hemodynamic correlates of target stimulus processing in single-tone (targets alone) and two-tone (targets and standard tones) auditory oddball tasks. The primary hypothesis was that processing of salient stimuli in both contextual conditions would engage the same spatially distributed cortical and subcortical networks observed in previous oddball fMRI studies. Results were consistent with this hypothesis and suggest that the brain engages many potentially useful brain regions during salient stimulus processing despite the low probability that said regions are necessary for task performance, which likely reflects a form of “adaptive reflexive processing”. Results were also consistent with ERP data that shows that the N1 is larger for single-tone tasks by showing greater amplitude of hemodynamic response for single-tone targets, relative to two-tone targets, in bilateral temporal cortex and bilateral inferior lateral frontal cortex. The results are discussed as they relate to the understanding of neurocognitive function pertaining to contextual manipulations in general, and orienting processes in particular.     

The immune response of healthy adults to a reduced dose of hepatitis B vaccine

Three hundred thirty-six medical personnel from hemodialysis centers were treated with three doses, 20 μg each, of the Merck hepatitis B vaccine (at 0, 1, and 6 months). Within 1 month after the first injection, 41% converted to anti-HBs positivity; after the second injection the conversion rate rose to 80–90%; and after the booster, to 96–98%. The later rate remained unchanged during the 18-month follow-up period. Only 2.8% of those vaccinated did not respond to the vaccine. The patterns of immune responses to 20-μg doses were found to be exactly the same as to 40-μg doses. It is suggested that reduced doses of vaccine should be as efficacious as the larger ones.