QRS Amplitude of ECG in Normal Humans: Effects of Orthostatic Challenge on Linear and Nonlinear Measures of Beat-to-Beat Variability

When respiratory signal is not available, it can be derived from the surface electrocardiogram (ECG) with some limitations. This is particularly useful to understand the contribution of respiratory variability in several conditions where there is an increased risk of cardiovascular mortality. ECG-derived respiratory signal is also more valuable in situations of 24-h ECG records, where the continuous respiratory signal is not usually available. We have previously shown that respiratory variability in tidal volume significantly increases during standing posture compared to supine posture. In this study, we obtained respiratory signal derived from the ECG in 17 normal adult controls without a history of heart disease and quantified the time of occurrence of peaks and amplitudes or the QRS complex and performed cross-spectral analysis between R-R (interbeat) interval and the QRS-amplitude time series sampled at 4 Hz. Our findings show that the supine QRS amplitude HF power (0.15–0.5 Hz) correlates significantly with the R-R HF power (r (0.62; n (17; p ((0.004). However, this was negatively correlated in standing posture (r (−0.5; n (17; p (0.04). While there was a significant decrease of R-R HF power upon standing (p(0.01), there was a significant increase in QRS amplitude HF power (p (0.004). These findings indicate that the variability of QRS amplitude behaves differently in standing posture compared to R-R time series and thus the supine QRS amplitudinal changes may reflect more closely, the respiratory variability. These findings are discussed in relation to the increased QRS amplitude variability in conditions such as coronary artery disease and other populations at risk for increased cardiac mortality.     

Experience with anti‐tumor necrosis factor‐α therapy in India

Aims: To review the Indian experience with anti‐tumor necrosis factor (TNF)‐α therapy. Methods: ‘PubMed’ and ‘IndMED’ were searched for Indian studies on anti‐TNF‐α therapy. Data were compiled and analysed. Results: Data on infliximab from 176 patients from five different series were collated. One hundred and forty‐seven had ankylosing spondylitis (AS), nine had polyarticular juvenile idiopathic arthritis (JIA), 12 had rheumatoid arthritis (RA), six had undifferentiated spondyloarthropathy, one had inflammatory bowel disease‐related spondyloarthritis and one had psoriatic arthritis. Thus, 155/176. (88%) had spondyloarthropathy (SpA). No screening for latent tuberculosis was done in any of the studies. One series comprising 108 cases of AS, used 3 mg/kg infliximab infusions (instead of 5 mg/kg) at 8‐weekly intervals with omission of the 2‐week and 6‐week doses. All others with SpA (n = 47) followed the standard protocol: 171/176 patients had a significant improvement. Reactivation tuberculosis developed in 5/47 (10.6%) SpA patients treated with standard doses of infliximab. This amounted to 56 times increased risk compared to baseline (0.187%). None of the 129 patients treated with 3 mg/kg infusions of infliximab developed reactivation tuberculosis (AS ?108, RA ?12, JIA ?9). The lone study on etanercept showed good efficacy in 40 patients with RA. However, seven serious adverse events occurred. Conclusions: Infliximab showed expected efficacy in SpA, RA and JIA. Reactivation tuberculosis developed in 10.6% of the SpA group treated with standard regimen. Patients treated with lower doses of infliximab which included a large subgroup of SpA patients and those with RA or JIA did not develop tuberculosis.     

Study of gastro‐oesophageal reflux disease in patients with mild‐to‐moderate chronic obstructive pulmonary disease in India

Background and objective: To study the incidence and pattern of gastro‐oesophageal reflux disease (GORD) in patients with mild‐to‐moderate chronic obstructive pulmonary disease (COPD) using dual‐probe 24‐h oesophageal pH recording. Methods: This was a prospective study of 50 patients with mild‐to‐moderate stage COPD based on the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines. A detailed history of illness along with spirometry was done in all patients. In the study group, reflux symptoms were measured using a validated scoring system. All the patients underwent oesophageal manometry and dual‐probe 24‐h oesophageal pH recording. Results: Symptoms of gastro‐oesophageal reflux were present in 38 patients. Twenty‐four‐hour oesophageal pH monitoring revealed pathological reflux in 31 out of 38 symptomatic and 8 out of 12 asymptomatic patients. The overall rate of GORD was 78% in our study. Only distal GORD was observed in 11 (28.9%), and both distal and proximal GORD was observed in 20 (52.6%) out of the 38 symptomatic subjects. In the remaining 12 asymptomatic patients, eight had GORD. Distal GORD was present in six (50%) patients, and two (16.6%) had both distal and proximal GORD in this group. Isolated proximal GORD was not observed in any patient. Conclusions: There is an increased occurrence of GORD in patients with even mild‐to‐moderate COPD.     

Low-dose recombinant interferon therapy in anti-HBe-positive chronic hepatitis B in Asian Indians*

Approximately 15% of Indian patients with hepatitis B virus (HBV)-related chronic liver disease (CLD) have infection with precore mutant forms. These patients are likely to have an aggressive course. There are equivocal reports of success with interferon therapy of mutant infection in the West. This therapy has not been evaluated in precore mutant-related CLD in Asian Indians. Eighteen patients (mean age 38.2 ± 12 years, M: F: 17: 1) with biopsy proven CLD and precore mutant HBV infection (hepatitis B surface antigen (HBsAg) positive, hepatitis B e antigen (HBeAg) negative, anti-HBe positive, HBV-DNA positive) were included. Interferon alpha 2b was given at 3 mIU on alternate days for 4 months. Serology, determination of HBV-DNA (both by dot-blot hybridization and polymerase chain reaction) and liver biopsy were repeated after completion of the therapy. Response to interferon therapy was defined as loss of HBV-DNA by dot-blot hybridization. Thirteen (72.2%) patients responded to the treatment (responders). Mean alanine aminotransferase levels (83 ± 12 vs 55 ± 29 IU/L, P < 0.01) and the histological activity index (15 ± 1.4 vs 12 ± 1.3, P < 0.01) significantly decreased in the responders compared with initial values. Serum albumin levels also improved at the end of the therapy (3.5 ± 0.4 g/dL vs 3.8 ± 0.4 g/dL, P= 0.07). During follow up, seven of the 13 (54%) responders relapsed; cirrhotics relapsed more often than chronic hepatitis patients (P < 0.05). All 18 patients, however, continued to be HBV-DNA positive at the end of follow up. This study concluded that: 1. Interferon therapy is beneficial, albeit to a limited extent, in HBV precore mutant-related chronic liver disease in Asian Indians. 2. It is ineffective in eliminating the mutant HBV infection, which explains the high relapse rate. 3. Prolonged low-dose interferon therapy alone or in combination with newer nucleoside analogues should be evaluated in these patients.     

Soluble (s)CD23 levels in a parasitized population from Papua New Guinea

Levels of sCD23, total and specific IgE were found to be considerably elevated in the plasma of a helminth infected population from Papua New Guinea. Using age-corrected data, a significant negative correlation was seen between sCD23 and total IgE in the young, at a time when hookworms are being rapidly acquired, and total IgE levels are rising most dramatically. It is suggested on the basis of this data that this inverse correlation is due to the stabilizing effect of IgE on the FceRII receptor in vivo, and that the high levels of sCD23 seen in hookworm infected individuals are partly responsible for the high levels of IgE recorded in these patients.     

The relative contribution of antibody production and CD8+ T cell function to immune control of Trypanosoma cruzi

The life cycle of the protozoan parasite Trypanosoma cruzi in mammalian hosts includes both non-dividing trypomastigote forms which circulate in the blood and replicating intracellular amastigotes which reside within the cytoplasm of a variety of host cells. In this study we have used mice with induced mutations in genes responsible for either antibody production or cytolytic T lymphocyte (CTL) function to examine the relative contributions of these effector mechanisms to control of T. cruzi. Mice deficient in the production of antibodies exhibited a delay in the rise in acute phase parasitaemia and an extended time to death relative to mice lacking CD8⁺ T cells. Nevertheless, B cell deficient mice eventually succumbed to the infection. Prior infection with an avirulent strain of T. cruzi failed to protect either CD8⁺ T cell-deficient mice or B cell deficient mice from challenge infection with virulent parasites. In contrast, mice with disruptions in the genes controlling perforin- or granzyme B-mediated cytolytic pathways had parasitaemia and mortality rates similar to wild-type mice and were protected from secondary infection by prior exposure to avirulent parasites. These results 1) confirm that antibody production, although secondary in importance to cellular responses, is nevertheless absolutely required and 2) perforin- or granzyme B-mediated lytic pathways are not required for control of T. cruzi infection.     

Can mothers identify malnutrition in their children?

To assess mothers' perceptions about malnutrition and theirability to identify malnutrition in their own children, 339children aged 3–35 months and their mothers were studiedin two urban hospitals in Dhaka, Bangladesh, and in a communityclinic. The weight, height, and mid-upper arm circumferenceof the children were measured, and their mothers were interviewed.Child nutritional status according to their mother's statementand anthropometrically assessed nutritional status were compared.Sixty per cent of the mothers correctly identified better nutritionalstatus (weight/age >75% of NCHS median) and 67% mothers correctlyidentified malnutrition (weight/age < 75% of NCHS median)in their children. Sixty-one per cent of mothers with less than5 years of formal education correctly identified better nutrition(weight/age >75%) whereas 38% mothers with more than 5 yearsof education correctly identified better nutrition. Correctidentification of malnutrition was made by 70% of mothers withless than 5 years of formal education, and 74% of educated mothersdid the same. As regards causes of malnutrition, 33% of mothers stated thatlack of food at home resulted in undernutri-tion in their children(mean weight-for-age of these children was 65% of the NCHS median).Mothers' suggestions for improving child health were: betterfood in 31% cases; treatment of illnesses in 22% cases; andboth in 42% cases. The results suggest that most of the mothersare able to identify malnutrition in their children, and 95%of them are aware of ways to improve it, and that the provisionof adequate food and health care may improve child nutritionalstatus.