Associations between air pollutants and blood pressure in an ethnically diverse cohort of adolescents in London, England

Longitudinal evidence on the association between air pollution and blood pressure (BP) in adolescence is scarce. We explored this association in an ethnically diverse cohort of schoolchildren. Sex-stratified, linear random-effects modelling was used to examine how modelled residential exposure to annual average nitrogen dioxide (NO2), particulate matter (PM2.5, PM10) and ozone (O3), measures in μg/m3, associated with blood pressure. Estimates were based on 3,284 adolescents; 80% from ethnic minority groups, recruited from 51 schools, and followed up from 11-13 to 14-16 years old. Ethnic minorities were exposed to higher modelled annual average concentrations of pollution at residential postcode level than their White UK peers. A two-pollutant model (NO2 & PM2.5), adjusted for ethnicity, age, anthropometry, and pubertal status, highlighted associations with systolic, but not diastolic BP. A μg/m3 increase in NO2 was associated with a 0.30 mmHg (95% CI 0.18 to 0.40) decrease in systolic BP for girls and 0.19 mmHg (95% CI 0.07 to 0.31) decrease in systolic BP for boys. In contrast, a 1 μg/m3 increase in PM2.5 was associated with 1.34 mmHg (95% CI 0.85 to 1.82) increase in systolic BP for girls and 0.57 mmHg (95% CI 0.04 to 1.03) increase in systolic BP for boys. Associations did not vary by ethnicity, body size or socio-economic advantage. Associations were robust to adjustments for noise levels and lung function at 11-13 years. In summary, higher ambient levels of NO2 were associated with lower and PM2.5 with higher systolic BP across adolescence, with stronger associations for girls.

A biophysical study of the interactions of palladium(II), platinum(II) and gold(III) complexes of aminopyridyl-2,2'-bipyridine ligands with RNAs and other nucleic acid structures

Metal compounds form an attractive class of ligands for a variety of nucleic acids. Five metal complexes bearing aminopyridyl-2,2'-bipyridine tetradentate ligands and possessing a quasi-planar geometry were challenged toward different types of nucleic acid molecules including RNA polynucleotides in the duplex or triplex form, an RNA Holliday four-way junction, natural double helix DNA and a DNA G-quadruplex. The binding process was monitored comparatively using different spectroscopic and melting methods. The binding preferences that emerge from our analysis are discussed in relation to the structural features of the metal complexes.

Air pollution and trajectories of adolescent conduct problems: the roles of ethnicity and racism; evidence from the DASH longitudinal study

PURPOSE

No known UK empirical research has investigated prospective associations between ambient air pollutants and conduct problems in adolescence. Ethnic minority children are disproportionately exposed to structural factors that could moderate any observed relationships. This prospective study examined whether exposure to PM2.5 and NO2 concentrations is associated with conduct problems in adolescence, and whether racism or ethnicity moderate such associations.

METHODS

Longitudinal associations between annual mean estimated PM2.5 and NO2 concentrations at the residential address and trajectories of conduct problems, and the potential influence of racism and ethnicity were examined school-based sample of 4775 participants (2002-2003 to 2005-2006) in London, using growth curve models.

RESULTS

Overall, in the fully adjusted model, exposure to lower concentrations of PM2.5 and NO2 was associated with a decrease in conduct problems during adolescence, while exposure to higher concentrations was associated with a flattened trajectory of conduct symptoms. Racism amplified the effect of PM2.5 (β = 0.05 (95% CI 0.01 to 0.10, p < 0.01)) on adolescent trajectories of conduct problems over time. At higher concentrations of PM2.5, there was a divergence of trajectories of adolescent conduct problems between ethnic minority groups, with White British and Black Caribbean adolescents experiencing an increase in conduct problems over time.

CONCLUSION

These findings suggest that the intersections between air pollution, ethnicity, and racism are important influences on the development of conduct problems in adolescence.

Neutrophil gelatinase-associated lipocalin is a biomarker of acute-on-chronic liver failure and prognosis in cirrhosis

BACKGROUND & AIMS

Acute-on-chronic liver failure (ACLF) is a syndrome that occurs in cirrhosis characterized by organ failure(s) and high mortality rate. There are no biomarkers of ACLF. The LCN2 gene and its product, neutrophil gelatinase-associated lipocalin (NGAL), are upregulated in experimental models of liver injury and cultured hepatocytes as a result of injury by toxins or proinflammatory cytokines, particularly Interleukin-6. The aim of this study was to investigate whether NGAL could be a biomarker of ACLF and whether LCN2 gene may be upregulated in the liver in ACLF.

METHODS

We analyzed urine and plasma NGAL levels in 716 patients hospitalized for complications of cirrhosis, 148 with ACLF. LCN2 expression was assessed in liver biopsies from 29 additional patients with decompensated cirrhosis with and without ACLF.

RESULTS

Urine NGAL was markedly increased in ACLF vs. no ACLF patients (108(35-400) vs. 29(12-73)μg/g creatinine; p<0.001) and was an independent predictive factor of ACLF; the independent association persisted after adjustment for kidney function or exclusion of variables present in ACLF definition. Urine NGAL was also an independent predictive factor of 28day transplant-free mortality together with MELD score and leukocyte count (AUROC 0.88(0.83-0.92)). Urine NGAL improved significantly the accuracy of MELD in predicting prognosis. The LCN2 gene was markedly upregulated in the liver of patients with ACLF. Gene expression correlated directly with serum bilirubin and INR (r=0.79; p<0.001 and r=0.67; p<0.001), MELD (r=0.68; p<0.001) and Interleukin-6 (r=0.65; p<0.001).

CONCLUSIONS

NGAL is a biomarker of ACLF and prognosis and correlates with liver failure and systemic inflammation. There is remarkable overexpression of LCN2 gene in the liver in ACLF syndrome.

LAY SUMMARY

Urine NGAL is a biomarker of acute-on-chronic liver failure (ACLF). NGAL is a protein that may be expressed in several tissues in response to injury. The protein is filtered by the kidneys due to its small size and can be measured in the urine. Ariza, Graupera and colleagues found in a series of 716 patients with cirrhosis that urine NGAL was markedly increased in patients with ACLF and correlated with prognosis. Moreover, gene coding NGAL was markedly overexpressed in the liver tissue in ACLF.

Measurement of the charged-pion polarizability

The COMPASS collaboration at CERN has investigated pion Compton scattering, π(-)γ→π(-)γ, at center-of-mass energy below 3.5 pion masses. The process is embedded in the reaction π(-)Ni→π(-)γNi, which is initiated by 190 GeV pions impinging on a nickel target. The exchange of quasireal photons is selected by isolating the sharp Coulomb peak observed at smallest momentum transfers, Q(2)<0.0015  (GeV/c)(2). From a sample of 63,000 events, the pion electric polarizability is determined to be α(π)=(2.0±0.6(stat)±0.7(syst))×10(-4)  fm(3) under the assumption α(π)=-β(π), which relates the electric and magnetic dipole polarizabilities. It is the most precise measurement of this fundamental low-energy parameter of strong interaction that has been addressed since long by various methods with conflicting outcomes. While this result is in tension with previous dedicated measurements, it is found in agreement with the expectation from chiral perturbation theory. An additional measurement replacing pions by muons, for which the cross-section behavior is unambiguously known, was performed for an independent estimate of the systematic uncertainty.

Epidemiology and outcome of sepsis syndromes in Italian ICUs: a muticentre, observational cohort study in the region of Piedmont

BACKGROUND

Sepsis is an important cause of mortality and morbidity in the intensive care unit (ICU). We performed a study to describe the epidemiology of sepsis syndromes in patients admitted to ICUs of the Piedmont region.

METHODS

In this prospective, multicentre, observational study, all 3902 patients admitted to a network of 24 ICUs from 17 hospitals during a 180 day period (April 3-September 29, 2006) were included. Patients were followed from the first day of admission until death or ICU discharge.

RESULTS

The incidence of sepsis during the ICU stay was 11.4% (N.=446), corresponding to an incidence of 25 cases/100,000 inhabitants/year; 141 (31.6%) patients had only sepsis, 160 patients had severe sepsis (35.9%) and 145 patients (32.5%) had septic shock In 227 patients (50.9%), sepsis was observed within 48 hours after admission to the ICU, and 219 patients (49.1%) developed ICU-acquired sepsis. The main sources of infection were the lungs, abdomen, and urinary tract. ICU mortality was higher (41.3 vs. 17.3%, P<0.0001) and the median ICU length of stay longer (15 vs. 2 days, P<0.0001) in patients with sepsis than in those without sepsis. The mortality rate increased with the severity of sepsis. ICU-acquired sepsis was associated with higher ICU mortality rates than sepsis occurring within 48 hours of ICU admission (49.8 vs. 33.0%, P<0.0001).

CONCLUSION

Sepsis is a common occurrence in critically ill patients. Our data underscore the regional variability in the epidemiology and outcome of sepsis syndromes and may be useful to guide appropriate resource allocation.

First measurement of chiral dynamics in π- γ → π- π- π+

The COMPASS Collaboration at CERN has investigated the π- γ → π- π- π+ reaction at center-of-momentum energy below five pion masses, sqrt[s]<5m(π), embedded in the Primakoff reaction of 190 GeV pions impinging on a lead target. Exchange of quasireal photons is selected by isolating the sharp Coulomb peak observed at smallest momentum transfers, t'<0.001  GeV2/c2. Using partial-wave analysis techniques, the scattering intensity of Coulomb production described in terms of chiral dynamics and its dependence on the 3π-invariant mass m(3π)=sqrt[s] were extracted. The absolute cross section was determined in seven bins of sqrt[s] with an overall precision of 20%. At leading order, the result is found to be in good agreement with the prediction of chiral perturbation theory over the whole energy range investigated.

Endoscopic banding for esophageal variceal bleeding: technique and patient outcome

AIM

Endoscopic variceal ligation (EVL) is recommended for the treatment of esophageal variceal bleeding. The aim of this study was to assess the most cost-effective timing of endoscopic follow-up after variceal eradication.

METHODS

Cirrhotics with esophageal varices treated between January 2008 and January 2009 until reached variceal obliteration were retrospectively analyzed for technical aspects and for outcomes.

RESULTS

Out of 127 patients treated with EVL, 103 were included. Number of sessions to achieve variceal obliteration and number of bands for each session were 2.8±1.3 (range 1-7) and 4.6±1 (range 2-7), respectively. The placement of >5 bands per session was not associated with higher incidence of complications (19.6% vs. 17.8%, P=ns). Esophageal ulcers were observed in 42% of patients when the interbanding interval was <20 days (versus 15% for interval >20 days, P<0.05). Once obliteration was achieved, varices reappeared in 28% of patients; the early appearance of small varices was not associated with bleeding.

CONCLUSION

A longer interbanding interval reduces the incidence of procedural-related complications. After variceal obliteration an early endoscopic control is not useful because it does not influence the approach and does not change the patient outcome.

Potential link between Helicobacter pylori and ischemic heart disease: does the bacterium elicit thrombosis?

Over the past fifteen years, numerous observations have linked Helicobacter pylori (H. pylori) infection to ischemic heart disease (IHD). Despite the controversial literature data, it has been postulated that if a role is plausible, it will be in the early events of the acute coronary syndrome. According to this model, we focused on the potential pathogenic mechanisms relating H. pylori to IHD like platelet aggregation and thrombosis. To identify all publications in this field, a MEDLINE search of studies published in English from 1965 to 2009 was conducted. Although very few investigations were found, these showed data of paramount importance. In particular, it has been demonstrated that some strains of H. pylori bind von Willebrand factor and interact with glycoprotein Ib to induce platelet aggregation in humans. In experiments from animal models, such infection promoted the formation of platelet aggregates by both a marked increase in the flux of rolling leukocytes and the appearance of platelet and leukocyte-platelet aggregates in gastric venules. This aggregate formation was abrogated by antibodies against specific adhesion molecules (L- and P-selectin). The future challenge is to gain more knowledge in this field and to translate these information into clinical practice.

Quality-of-life measurement in patients with inflammatory bowel disease receiving social support

BACKGROUND

Crohn's disease and ulcerative colitis, referred to as inflammatory bowel diseases, affect mainly young adults and have an elevated morbidity and a negative effect on quality of life. This study aimed to compare the health-related quality of life between 2 randomized groups of patients with inflammatory bowel disease: (1) the supported group (SG), patients receiving social support for an 18-month period, and (2) the control group (CG), patients receiving no social support.

METHODS

Health-related quality of life was assessed at 4 moments with the Portuguese versions of the Medical Outcomes Study Short Form 36 and the Inflammatory Bowel Disease Questionnaire (IBDQ), both validated in Brazil.

RESULTS

In the SG, using analysis of variance for repeated measures complemented by the Bonferroni test positive variations were observed (1) in the Social Aspects domain, between the first and third evaluations (P = 0.044), and (2) in the Emotional Aspects domain, between the first and second and the third and fourth evaluations (P = 0.029).

CONCLUSIONS

In the sample studied, social support, measured by use of the Inflammatory Bowel Disease Questionnaire, had a positive impact on the social and emotional aspects of quality of life.

Effects of Lactobacillus GG on genes expression pattern in small bowel mucosa

BACKGROUND AND AIMS

Probiotics have been used for cure and prevention of several clinical conditions. However, further insights into the mechanism of action are needed to understand the rationale of their use. The aim of this study was to investigate the influence of Lactobacillus GG on the genetic expression patterns in the small bowel mucosa.

METHODS

Six male patients (38+/-5 years) with endoscopically proven oesophagitis were enrolled. All patients were treated for 1 month with esomeprazole and randomised to receive Lactobacillus GG or placebo. After 1 month of treatment, upper endoscopy was repeated. Biopsies of the duodenal mucosa were taken prior to and after the treatment, and the genes expression patterns were assessed using GeneChip Human U133A array. Genes with significant expression changes were selected and analysed to identify specific cellular pathways modified by Lactobacillus GG. To support the array data, 10 target genes were studied using Syber-Green PCR.

RESULTS

Microarray analysis showed that Lactobacillus GG administration determined the up- and down-regulation of 334 and 92 genes, respectively. Real-time PCR confirmed the reliability of the analysis. Lactobacillus GG mainly affected the expression of genes involved in immune response and inflammation (TGF-beta and TNF family members, cytokines, nitric oxide synthase 1, defensin alpha 1), apoptosis, cell growth and cell differentiation (cyclins and caspases, oncogenes), cell-cell signalling (ICAMs and integrins), cell adhesion (cadherins), signal transcription and transduction.

CONCLUSIONS

These data indicate that administration of Lactobacillus GG is associated with a complex genetic response of the duodenal mucosa, reflected by the up- and down-regulation of several genes involved in specific cellular pathways.

Bronchial hyperresponsiveness and analysis of induced sputum cells in Crohn's disease

With the aim of investigating the presence of latent inflammatory process in the lungs of patients with Crohn's disease, 15 patients with Crohn's disease were evaluated by spirometry, the methacholine challenge test, induced sputum, and skin tests for inhaled antigens. Serum IgE, erythrocyte sedimentation rate and hematocrit were also determined. The patients were compared with 20 healthy controls by the Mann-Whitney and Fisher exact tests. Their respiratory physical examination was normal. None had a personal or family history of clinical atopy. None had a previous history of pulmonary disease, smoking or toxic bronchopulmonary exposure. None had sinusitis, migraine, diabetes mellitus, or cardiac failure. Four (26.6%) of the patients with Crohn's disease had a positive methacholine challenge test whereas none of the 20 controls had a positive methacholine test (P = 0.026, Fisher exact test). Patients with Crohn's disease had a higher level of lymphocytes in induced sputum than controls (mean 14.59%, range 3.2-50 vs 5.46%, 0-26.92%, respectively; P = 0.011, Mann-Whitney test). Patients with Crohn's disease and a positive methacholine challenge test had an even higher percentage of lymphocytes in induced sputum compared with patients with Crohn's disease and a negative methacholine test (mean 24.88%, range 12.87-50 vs 10.48%, 3.2-21.69%; P = 0.047, Mann-Whitney test). The simultaneous findings of bronchopulmonary lymphocytosis and bronchial hyperresponsiveness in patients with Crohn's disease were not reported up to now. These results suggest that patients with Crohn's disease present a subclinical inflammatory process despite the absence of pulmonary symptoms.

Effects of oral nutritional supplementation on the intestinal mucosa of patients with AIDS

Weight loss is a major component of the clinical syndrome in patients with acquired immunodeficiency syndrome (AIDS). The impact of malnutrition on the outcome of the disease has been unappreciated in many investigations. The authors evaluated the effects of oral nutritional supplementation on the morphology and immunology of the intestinal mucosa of patients with AIDS. Twelve patients with AIDS without diarrhea or opportunistic infections, with at least 10% of body weight loss over 1 year, were submitted to anthropometric measures, peripheral blood T-lymphocyte counts, and peroral jejunal biopsy before and after oral nutritional supplementation. An industrialized peptide-based formula containing omega-3 fatty acids was given for 6 weeks. Jejunal samples were analyzed by histomorphometry, including villous-to-crypt ratio, lamina propria, and intraepithelial lymphocyte count. Immunologic assessment of the intestinal mucosa was made by indirect immunoperoxidase using monoclonal antibodies against CD3, CD4, and CD8. Seven patients with irritable bowel syndrome and two healthy volunteers were selected as a control group for histologic and immunohistochemical comparisons. After 6 weeks the patient group maintained their body weight and increased their tricipital fold. The number of peripheral blood T cells, albumin, transferrin, and the number of CD3+, CD4+, and CD8+ cells in jejunal mucosa as well as the intestinal morphometry remained stable. Oral supplementation contributed to maintaining body weight and may constitute a reasonable adjuvant therapeutic tool against AIDS progression.

Humoral intestinal immunity in systemic lupus erythematosus

Forty-five patients with systemic lupus erythematosus (SLE) underwent a cross-sectional study to evaluate intestinal secretory immunity. Peroral jejunal biopsy with histologic and immunohistochemical assessment of the mucosa were carried out in the patients and in 12 healthy volunteers. It was observed that an altered pattern of immunoglobulin-bearing plasma cells distributed in the lamina propria and complementary components were invariably present, mainly in the patients with active disease. The basement membrane of the intestinal crypt epithelium exhibited immunoglobulin and complementary deposits, similar to the lupus band test. None of the immunologic findings correlated with the medical treatment and with the peripheral blood analysis. The local changes in humoral immunity in patients with SLE did not correlate with gastrointestinal symptoms and may reflect the systemic effects of the disease.

Clinical patterns of diarrhea in AIDS. A retrospective study at the Federal University Hospital, Rio de Janeiro

Three hundred and fifty two medical records of AIDS inpatients were analysed in a retrospective study to establish the frequency, clinical patterns and etiology of AIDS-related diarrhea. Diarrhea was observed in 58.8% of the patients, being a chronic symptom in 65.7%, and the first complaint in 24.6%. The most common cause of diarrhea was coccidea and the etiology remained unknown in 56.1% of the patients. Routine stool examination was the most sensitive method in the diagnosis of diarrhea. In countries with limited resources, the use of stool examinations seems to provide appropriate clinical management. The implementation of an objective protocol could improve the etiologic diagnosis of AIDS-related diarrhea without the burden of more complex and invasive technologies.

Quantitative and qualitative changes in intestinal immunoglobulin-bearing plasma cells in jejunal mucosa of 52 HIV-infected patients

1. The purpose of the present study was to evaluate the intestinal secretory immunity of HIV-infected patients. Jejunal biopsies were obtained with a Watson capsule from 52 HIV-infected patients and compared to a control group consisting of 12 healthy subjects, matched for age and sex. IgA- and IgM-containing plasma cells were studied by immunofluorescence by two independent observers who had no knowledge of the history of the slides. 2. The IgA and IgM plasma cell density was significantly decreased in HIV-infected patients when compared to the controls (31/52 for IgA and 42/52 for IgM in the HIV group and normal density in all controls). The depletion of intestinal plasma cells was an early feature of HIV disease and did not correlate with diarrhea, enteropathogens or mucosal atrophy. Although IgA plasma cell depletion has been described in HIV infection, this is the first report of IgM cell density reduction. 3. A peripheral fluorescence pattern was observed in the intestinal cells of HIV-infected patients, contrasting with the normal cytoplasmic fluorescence pattern seen in controls. The cells presenting a rim of peripheral fluorescence in HIV disease might correspond to immature B lymphocytes. 4. The intestinal plasma cell depletion may result in hampered mucosal defense in HIV disease, and is likely to be a direct consequence of T lymphocyte function impairment. 5. The data indicate that the intestinal secretory immune system is altered in AIDS and also in the early stages of HIV disease.

Loss of mucosal CD4 lymphocytes is an early feature of HIV infection

T cell subsets in the gut mucosa are distinct populations and their imbalance in HIV has specific implications in infection. Alterations in T cell subsets in duodenal biopsies were investigated in 17 asymptomatic HIV patients, 24 AIDS patients and 10 controls with non-ulcer dyspepsia. Immunohistochemistry and immunofluorescence using MoAbs to CD3, CD4, CD8, CD68, CD45RA, CD45RO and gp120 were performed on frozen sections. In the lamina propria, there was a significant depletion of CD4+ cells at all stages of HIV, but the density of CD8 lamina propria cells was increased. Intraepithelial lymphocytes were decreased in AIDS patients. There was a significant correlation between cellular density and mucosal CD3+ lymphocytes, and between mucosal CD3+ and CD8+ lymphocytes. Although mucosal CD4,CD45RO+ 'memory' cells were decreased, CD8,CD45RO+ 'memory' cells were increased. Mucosal CD4+ lymphocyte depletion occurred early in HIV, and thus their role in mucosal protection against opportunistic infection should be revised. Mucosal CD8+ lymphocytes initially increased, but decreased when CD4 blood counts were depleted, perhaps contributing to loss of host protection against infection. Intraepithelial lymphocyte depletion may also contribute to opportunistic infection.

The incidence of pathological gambling among Native Americans treated for alcohol dependence

The prevalence rate of potential and pathological gambling was examined among Native American and Caucasian patients (n = 85) being treated for alcohol dependence. Previous studies with alcohol-dependent (mainly Caucasian) populations revealed 10-15% to have gambling problems. This study, the first to measure pathological gambling among a Native American population, utilized the South Oaks Gambling Screen and was administered in a group setting, between 1/91 and 4/91 on the alcohol treatment ward of the Ft. Meade Veterans Administration Hospital. Results showed that 22% of the Native Americans studied (compared to 7.3% Caucasian), scored in a range indicating a probable pathological gambling addiction. Furthermore, 41% of the Native Americans studied (compared to 21.3% Caucasian) admitted to some difficulty with gambling. Education and treatment is encouraged to help stem projected radical increases in pathological gambling and related problems among this cultural group as Native American gambling becomes widespread.

HIV particles detected in spermatozoa of patients with AIDS

In this paper the Authors describe the presence of HIV particles on and in mature spermatozoa either ejaculated by AIDS patients or incubated in vitro with HIV. Both kinds of spermatozoa have particles localized around the sperm organelles. In the first case, the nucleoid of the virus can be enveloped by a membrane-like coat or be devoid of it and form buddings in the plasma membrane. In the in vitro infected spermatozoa, only membrane enveloped nucleoids are present, and no process of budding can be found. The Authors conclude considering that the spermatozoa of the AIDS patients can be penetrated by the virus particles in different moments of their life, and show the HIV particles in different stages of their cycle: some of them have freshly penetrated the sperm, and are still contained in a membrane-like coat, others are replicated and are budding through the sperm plasma membrane. On the contrary, in vitro infected spermatozoa have only freshly penetrated virus particles, and lack buddings and membrane-free nucleoids. The presence of the HIV virus in spermatozoa is substantiated by labelling with monoclonal or polyclonal anti-HIV antibodies.

[Jejunal biopsy in AIDS]

Histopathological changes in small bowel biopsy from 5 patients with acquired immunodeficiency syndrome are reported. The main abnormalities were villous atrophy, severe mononuclear infiltrate and enhanced regenerative activity with high number of mitosis in the crypts.

Effect of ascorbic acid on increased bronchial responsiveness during upper airway infection

We investigated the acute effect of ascorbic acid on histamine bronchial responsiveness (PC 20: concentration causing a 20% fall in FEV1) in 9 hospital staff members with upper respiratory tract infection (URI) and cough. Subjects were examined within 5 days from the start of illness and 6 weeks after. On day 1, the reproducibility of PC20 was assessed by 2 consecutive inhalation challenges 1 h apart; the two values were closely related (r = 0.96, p less than 0.001). Five subjects had bronchial hyperresponsiveness (PC20 less than 8 mg/ml histamine). On the following day, PC20 was measured before and 1 h after oral intake of 2 g ascorbic acid. Vitamin C produced a significant increase in average PC20 (p less than 0.01) from 7.8 +/- (SE) 1.2 to 25.1 +/- (SE) 1.2 mg/ml. None had airway hyperresponsiveness after treatment. Six weeks after the onset of URI, bronchial responsiveness was normal in all the subjects but one. The mean PC20 was 15.5 +/- (SE) 1.25 mg/ml, significantly higher than during URI (p less than 0.05); after ascorbic acid it increased nonsignificantly to 25.7 +/- (SE) 1.35 mg/ml. Our results indicate that vitamin C inhibits the transient increase in bronchial responsiveness occurring in otherwise normal subjects during URI.

A freeze-fracture study of human bronchial epithelium in normal, bronchitic and asthmatic subjects

Tight junctions (TJ) play a major role in maintaining the integrity of epithelia. Damage of conducting airway surface epithelium is commonly observed in asthma, and recent data suggest that epithelial cells modulate airway smooth muscle tone by the production of relaxant factor(s). To evaluate the ultrastructure of tight junctions (TJ) in human bronchial epithelium of normal and diseased lung, biopsy samples were obtained by fiberoptic bronchoscopy in three normal healthy subjects, four asthmatic patients with bronchial hyperreactivity to methacholine and one heavy smoker with chronic bronchitis. Specimens were examined by electron microscopy, using both thin sections and freeze-fracture techniques. In normal subjects two types of TJ were identified, based on 27 type I, 23 type II junctional areas. Epithelium from the patient with chronic bronchitis showed extensive mucous metaplasia and only junctions of the second type. Extensive epithelial damage was detected in asthmatic subjects, so that a few TJ could be found. Varying degrees of TJ abnormalities were observed and the possible role of such ultrastructural derangements was discussed.

[Immunologic study of the non-pathogenic bacterial flora of the small intestine in children with persistent diarrhea]

Twenty five children with diarrhea were studied. Ten children without diarrhea or that had the last episodic one year before biopsy, represented the control group. Jejunal juice and biopsy specimens obtained from each patient were cultured, and bacteria obtained from these were tested against a further piece of mucosa and sample of pure juice from the same patient, to determine the presence within them of antibody against the small bowel bacteria. Duodenal mucosae antibody against non-pathogenic bacteria was demonstrated in 95% of children with diarrhea and only 25% of control group. The immunoglobulin classes involved, IgA and IgM, suggest a strong local immune system stimulation, although a systemic immune response can not be excluded since IgG was frequently found in the mucosa.

[Experience with peroral biopsy of the small intestine at the University Hospital--Federal University of Rio de Janeiro]

The experience with 103 jejunal biopsies in the Rio de Janeiro University Hospital--UFRJ, from January 1983 to June 1985 is presented. It is reported the effectiveness of the method and the low number of complications. The importance as a valuable complementary method of diagnosis and the usefulness in the small intestine disease's scientific investigation is emphasized.

Hemoglobin solution and the oxyhemoglobin dissociation curve

1) A study was carried out to determine the oxyhemoglobin dissociation curve of stroma-free hemoglobin solution and factors which influence it, (pH; 2,3 DPG). 2) To simulate acute volume replacement, dilution experiments, in vitro, were performed employing both hemoglobin solution and Ringer's lactate in whole blood. 3) It was determined that stroma-free hemoglobin solution has a left-shifted oxyhemoglobin dissociation curve which responds to pH change but not to the addition of 2,3 DPG. 4) The dilutional effect of hemoglobin solution when mixed with whole blood in volumes up to 50% was to left-shift the oxyhemoglobin curve, unlike the effect of Ringer's lactate (no change). 5) This may have importance in the hemodynamic compensatory response to acute normovolemic anemia.