Generation of reactive oxygen species by blood monocytes during acute Plasmodium knowlesi infection in rhesus monkeys.

The status and kinetics of monocyte activation during acute P. knowlesi infection was investigated by latex-induced, luminol-dependent chemiluminescence (CL) response. The contribution of various reactive oxygen species (ROS) to CL response was estimated before infection and at peak parasitaemia (day 7 post infection) by using scavengers of ROS (benzoate, catalase and superoxide dismutase). The chemiluminescence index (CLI) was not found to be significantly different from controls on day 2 postinfection, but was significantly higher on days 5 and 7 postinfection. Hydroxyl radical (OH.) production was considerably elevated, whereas superoxide anion (O2-.) and hydrogen peroxide (H2O2) production dropped following infection. These changes in generation of ROS are discussed in relation to the progression of parasitaemia to high levels, immunopathology and immunosuppression during acute P. knowlesi infection.

Fluid restriction does not improve the outcome of acute meningitis.

The objective of this prospective study was to examine the effect of fluid restriction on body water and the outcome of children with acute meningitis. Fifty consecutively hospitalized children with acute meningitis, divided into two groups (A, without hyponatremia; and B, with hyponatremia), were randomly assigned to receive either normal maintenance (M) or restricted (R subgroup) (65 to 70% of M subgroup) fluids during the first 48 hours. Total body water, extracellular water (ECW), serum and urinary sodium and plasma and urinary osmolality were measured at admission and after 48 hours. In both groups children receiving restricted fluids showed a significant decrease in the mean total body water and ECW whereas body water remained unchanged in those on maintenance fluids. Children having an ECW reduction of 10 ml/kg or more in 48 hours had a significantly lower intact survival (10 of 28, 36%) than those with < 10 ml/kg or no reduction of ECW (15 of 22, 64%) (P < 0.05). The mortality was also higher in the former (7 of 28, 25%) than in the latter (2 of 22, 9%). On multiple stepwise regression analysis, ECW volume at admission (partial r2 0.20), ECW loss in 48 hours (partial r2 0.13) and plasma osmolality at admission (partial r2 0.22) were significantly related to outcome. We conclude that fluid restriction does not improve the outcome of acute meningitis. Indeed a decrease in ECW volume at 48 hours increases the likelihood of adverse outcome.

Nitrites and L-citrulline levels in copper intrauterine device users.

The mechanism of copper in limiting intrauterine infections in intrauterine device (Cu IUD) users is poorly understood. Copper ions may enhance the release of reactive oxygen radicals, which in turn decrease the release of reactive nitrogen intermediates (RNI). RNI are known to have bactericidal effect. The present study compares the levels of RNI prior to Cu-T insertion and at different post-insertion intervals up to 12 weeks. The decrease in RNI was evident by one week and continued until 12 weeks. Therefore, the bactericidal effect of copper in IUD is via reactive oxygen intermediates. The superoxide anion inactivates this active intermediate nitric oxide. Therefore, excess of superoxide radical will markedly shorten the half-life of nitric oxide but will not prevent its conversion to nitrites and nitrates.

PIP: Copper ions may enhance the release of reactive oxygen radicals that decrease the release of reactive nitrogen intermediates (RNIs), known to have a bactericidal effect. The capability of the Copper-T IUD to generate RNIs was investigated in women seeking IUD insertion at a family planning clinic in Chandigarh, India. A significant decrease in nitric oxide levels was recorded from pre-insertion to 1 week post-insertion. Moreover, the values at 4 weeks' post-insertion were significantly lower than those at 1 week, and the 12 weeks' post-insertion level was lower than that recorded at 4 weeks. Uterine aspirate L-citrulline levels at 1 week post-insertion were significantly lower than pre-insertion levels; again, values at 4 and 12 weeks post-insertion were significantly less than those of the receding levels. There was no significant difference in levels of nitrites or serum L-citrulline before and after IUD insertion. Although the exact mechanism of the decrease in RNI levels at the local site after IUD insertion is unknown, it appears related to the sterile intrauterine milieu. At the peak of copper release, the inflammatory cells are activated to release reactive oxygen radicals. Copper potentiates the effect of superoxide dismutase, which influences the half-life of nitric oxide, but does not prevent its conversion to nitrites and nitrates.

Body water distribution in newborn infants appropriate for gestational age.

Total body water (TBW), extracellular water (ECW) and intracellular water (ICW) were measured within 6 h of birth in 99 appropriate for gestational age (AGA) infants. The two groups of infants included were term (mean +/- SD gestation 272 +/- 7 days) and preterm (mean +/- SD gestation 238 +/- 11 days) infants. The mean TBW +/- SD was 777 +/- 26 ml/kg in preterm infants and 737 +/- 26 ml/kg in term infants. The corresponding ECW was 349 +/- 26 ml/kg and 331 +/- 30 ml/kg respectively. Weight was the best correlate of TBW (r = 0.98) and ECW (r = 0.92) volumes. TBW per unit of body weight showed significant decline with increasing gestation (r = -0.54) and birth weight (r = -0.51). ICW per kg showed a moderate correlation with TBW (r = 0.63), whereas ECW per kg had a low correlation (r = 0.35) with it. TBW/kg in our infants was comparable to infants from other ethnic groups. ICW/kg, however, was consistently higher and ECW/kg lower at all stages of maturation in Indian infants as compared to Caucacian and Negroid infants.

A method of two-dimensional mapping of cortical perfusion by cylindrical transformation of HMPAO SPET data.

In order to synthesize three-dimensional information on relative regional blood flow (rCBF) from the cortical grey matter in 99Tcm-hexamethylpropyleneamine oxime (HMPAO) single photon emission tomographic (SPET) images into a single two-dimensional 'cortical peel' (CP) image, we developed a program that performs cylindrical transformation of SPET data. A sub-routine of this program performs measurements of cortex-to-cerebellum rCBF ratios for 54 cortical regions in the CP image. This program was used to establish a normative database derived from 30 young normal control subjects aged 28.7 +/- 6.9 years. The database was then used to express cortex-to-cerebellum rCBF ratios in four colour-coded ranges of normal standard deviation of the mean rCBF ratio across the cortical regions in the CP image. This CP method was implemented for 30 clinical HMPAO SPET studies in patients (n = 30, aged 71.8 +/- 4.2 years) with suspected dementia as well as several studies in aged healthy subjects (n = 8, aged 67 +/- 9.8 years). In 25/30 (83%) patients, all abnormalities seen on the tomographic display were evident on the corresponding CP image. No aged healthy subjects showed abnormalities on either the tomographic display or the corresponding CP image. An advantage of this technique is that the extent and severity of rCBF abnormalities are readily appreciated in one single image. This technique, in conjunction with the conventional multi-slice tomographic display, was a useful tool in identifying various patterns of rCBF abnormalities in the patients with clinically suspected dementia.

Maximum likelihood methods in vowel recognition: a comparative study.

Vowel classification accuracy is studied using a generalized maximum likelihood ratio method. It is shown that two simplifying assumptions can reduce computation times by as much as a factor of five while producing practically no change in recognition accuracy. The two simplifying assumptions remove cross correlation terms and produce an Euclidean distance discriminant function. The vowels are taken from 350 multisyllabic isolated words spoken by five male speakers. The vowels occur in a variety of preand postconsonantal contexts. The recognition scores obtained for vowels are 83 percent. The effect of grouping of similar vowels on recognition scores is found to be marginal. The high back and high front vowels show better recognition scores (92-94 percent). In general, recognition performance for individual vowels follows a definite trend with respect to. the vowel diagram. A reasonable similarity is observed between confusion matrix and the distribution of vowels in first and second formant frequency (F1 F2) plane.

Wheat threshing dust--a "new allergen" in April-May nasobronchial allergy.

OBJECTIVE: To identify the allergen(s) responsible for mid April-mid May nasobronchial allergy seen in North India. DESIGN: Case control study. SETTING: Children living in and around Chandigarh (urban, rural). SUBJECTS: 39 children suffering from wheat harvest period (mid April-mid May) respiratory allergy along with randomly selected controls. METHODS: Aerobiological surveys were done from March to June for identification of prevailing allergens for performing allergy tests. Patients were subjected to skin tests (ST), nasal provocation tests (NPT) and bronchial provocation tests (BPT) with extracts prepared from identified pollens and fungal spores. Specific IgE (SIgE) was assayed by ELISA and comparison between pre-season, season and post-season values made. RESULTS: 81% patients had ST positive to antigen of wheat threshing dust (WTD), 30% to fungal antigens, 14% to wheat dust antigens and none to the wheat plant (WP) antigens. Nasal provocation test and bronchial provocation tests were also positive to WTD in 80% and 66% patients, respectively. WTD SIgE was demonstrated in 77% of ST positive patients. CONCLUSIONS: These in vivo and in vitro tests confirm wheat threshing dust as a major causative inhalant allergen for the April-May nasobronchial allergy; in addition, fungal allergens also play a role in 1/3rd of these patients.

Water electrolyte homeostasis in acute bronchiolitis.

Children with acute bronchiolitis frequently require hospitalization and parenteral fluid therapy. Water retention due to impaired renal water excretion has been described in several pulmonary conditions in children. We studied 20 infants (3.6 +/- 2.9 months), hospitalized consecutively for acute bronchiolitis for water and electrolyte changes during the acute stage and compared them to those on recovery. Serum sodium and plasma osmolality, urinary sodium and osmolality were measured in all infants. Ten infants each were assigned alternatively to study body water compartment or renal water handling (water load excretion and free water excretion capacity) on the day of hospitalization and after recovery. Mean ( +/- SD) value of serum sodium of the infants at admission was 132.7 +/- 7.2 mEq/L which increased to 137.1 +/- 5.4 mEq/L on recovery (p < 0.05). Plasma osmolality changed from 284 +/- 14 mOsm/kg at admission to 294 +/- 10 mOsm/kg at recovery (p < 0.05). There was a significant decrease in urinary sodium from 54 +/- 39 mEq/L to 20 +/- 18 mEq/L and urinary osmolality from 415 +/- 213 mOsm/kg to 252 +/- 204 mOsm/kg at admission and at recovery, respectively. All 10 infants showed significant increase in total body water (mean +/- SD; 22.8 +/- 7.5 ml/kg) at admission as compared to that at recovery. The total body water (TBW) excess was mainly in extracellular water compartment (16.3 +/- 3.6 ml/kg). Seven of 10 infants had significant impairment in renal water excretion. Increase in maximum free water clearance of these 7 infants on recovery was 0.69 +/- 0.27 ml/min, i.e., 15 times more than that at admission. It is concluded that bronchiolitis of infancy is characterized by water retention which is caused by impaired renal water excretion. In the management of severe bronchiolitis careful attention to fluid therapy is mandatory; liberal fluid therapy may lead to water intoxication.

Bacterial contamination of reconstituted oral rehydration solution.

The extent and nature of bacterial contamination in oral rehydration solution reconstituted for use by individuals and for group of patients was studied. Twenty three volunteers (all qualified doctors) were asked to reconstitute a packet of prepackaged salt in half litre of clean unboiled water obtained from taps at their residence. Five ml aliquots of ORS were collected at 6, 12 and 24 hours after reconstitution for bacteriologic study. The water used by volunteers to reconstitute the ORS as well as throat swabs, peri-anal swabs and nail clippings of volunteers yielded pathogenic bacteria in all the subjects/samples. All the 23 specimens of ORS prepared by volunteers when cultured at 6 hours after reconstitution yielded pathogenic bacteria. The bacterial colony counts were found to be unacceptably high at 12 hours. Five ml samples of reconstituted ORS prepared in bulk in the children ward of PGIMER, Chandigarh were cultured at 12, and again at 24 hours after reconstitution on 10 different days. These yielded Klebsiella pneumoniae in 8 specimens (80%) and E. coli in 2 (20%). The bacterial colony count was unacceptably high, 12 hours after reconstitution.

Genital mycoplasma in intrauterine contraceptive device users.

PIP: The incidence association between genital mycoplasma isolation and copper IUD users is reported in this Indian study. The study group (IUD users) had 24.3% isolation of mycoplasma (16 of 66 subjects) compared with a figure of 11.4 in controls (non-IUD users). This was a statistically significant difference (P .001). Incidence of T-strains was more in the study group (18.2%) as compared with controls (2.2%) (P .001). Large-colony mycoplasmas (Mycoplasma hominis) had a statistically similar distribution in both study and control groups (6.1 and 9.2%, respectively) (P .005). In different categories of copper IUD users, the percentage of positivity of T-strains was higher in Copper t and Copper 7 users (33.3%) than in any other group which was statistically significant (P .001). However, M. hominis was found in the highest percentage among users of Lippes Loop (20%).^ieng

Role of 30 kDa antigen of enteric bacterial pathogens as a possible arthritogenic factor in post-dysenteric reactive arthritis.

BACKGROUND: Reactive arthritis (ReA)/Reiter's syndrome (RS) may be caused as a sequel of infections caused by enteric bacterial pathogens, although the mechanisms through, which different pathogens cause similar disease are not clear. AIM: This study was done to look for the presence and role of any common bacterial antigen among the pathogens isolated from such patients. MATERIALS AND METHODS: A total of 51 patients of ReA and 75 controls (three groups of 25 subjects each: Group 1: Patients who did not develop arthritic complications within 3 months after bacillary dysentery/diarrhea; Group 2: Patients with other arthritic diseases and Group 3: Normal healthy subjects) were included. The isolated enteric pathogens were tested to detect the immunodominant antigens. RESULTS AND CONCLUSIONS: A common 30 kDa antigen was found to be specifically present among seven arthritogenic enteric bacterial strains belonging to three genera, Salmonella, Shigella and Hafnia. Post-dysenteric ReA patients' sera show higher levels of immunoglobulin G, immunoglobulin M and immunoglobulin A antibodies against this antigen as compared to the controls. Lymphocytes of ReA patients recognize this antigen, proliferate and produce interleukin-2 in response to this antigen more than the lymphocytes of controls. 30 kDa antigen may be a common arthritogenic factor associated with post-dysenteric ReA/RS. The association of Hafnia alvei with post-dysenteric ReA is described for the first time. Four cases of mycobacterial ReA had an association with this antigen, suggesting that the arthritogenic antigen of mycobacteria and enteric bacteria may be of a similar nature.