Chronic residential crowding and children's well-being: an ecological perspective

Chronic residential crowding is associated with difficulties in behavioral adjustment at school, poor academic achievement, heightened vulnerability to the induction of learned helplessness, elevated blood pressure, and impaired parent-child interpersonal relationships among a sample of working-class, 10-to 12-year-old children living in urban India. The significant main effects of residential crowding on blood pressure and learned helplessness are moderated by gender. Residential crowding is positively associated with blood pressure only among boys and with helplessness only among girls. All analyses statistically control for household income. We then demonstrate that perceived parent-child conflict functions as an underlying, intervening process that largely accounts for several correlates of household crowding among children.     

Three thousand one hundred seventy-five primary inguinal hernia repairs: advantages of ambulatory open mesh repair using local anesthesia

BACKGROUND: Controversy exists over the relative advantages of open mesh repair compared with open stitching methods and the laparoscopic approach. STUDY DESIGN: Two thousand nine hundred six (2,906) consecutive unselected adult patients underwent 3,175 primary inguinal hernia repairs using polypropylene mesh, under local anesthesia on an ambulatory basis. The age range was 15-92 years. The study specifically investigated the postoperative course with regard to pain, complications, and time of return to work. RESULTS: There were no postoperative deaths and no cases of urinary retention. Two percent of patients developed a hematoma. The incidence of deep infection was 0.3%. No case of testicular atrophy occurred. Postoperatively 19% of patients used no analgesia at all; 60% used oral analgesics for up to 7 days. There was a gradual decrease in time of return to work over four successive 1-year periods. Manual workers returned to work in 15 days (median) in the first year, reducing to 9 days in the fourth year. The overall median time of return to work across the whole group was 9 days. There were eight recurrences with an 18-month to 5-year followup. CONCLUSIONS: Open mesh repair under local anesthesia is an effective day case technique, particularly in the elderly and medically unfit. The economic benefits are enhanced by low morbidity, early return to normal activities and low recurrence rates.     

A random graph model for the final-size distribution of household infections

In epidemiological/disease control studies, one might be interested in estimating the parameters community probability infection (CPI) and the household secondary attack rate (SAR), as introduced by Longini and Koopman. The quasi-binomial distribution I (QBD I) with parameters n, p and theta, introduced by Consul, is proposed as a model for the final-size distribution of household infections, where p (CPI) is the probability of an individual being infected from the community and theta (SAR) is the rate of secondary transmission of infection within household. An individual can be infected either from within the household or from the community. Let X be the total number of infected members in a household of size n. Then the distribution of X is given by the QBD I with the probability mass function: (formula: see text) with 0 < p < 1, theta > or = 0 such that p + n theta < 1. The epidemic model is derived from a directed random graph. Data from influenza epidemics in Asian and American households are used to test the model and a comparison is made with the Longini-Koopman model. It is shown empirically that the QBD I is as good as the L-K model in describing the household infectious disease data, and both models provide almost identical estimates for community and household transmission parameters although they are derived from different perspectives and conditions.     

Heart muscle cells acutely infected with Trypanosoma cruzi: characterization of electrophysiology and neurotransmitter responses

Primary cell cultures of mouse ventricular myocardium were infected with Trypanosoma cruzi, to study the consequences of T. cruzi-muscle cell interaction on the rate of spontaneous contractions, on the responses to norepinephrine, and on action potential parameters. Single cells or small cell groups of infected cultures were subjected to pharmacological and electrophysiological experiments. In concentrations ranging from 1 nM to 100 microM, norepinephrine exerted positive or negative chronotropic effects mediated by alpha-adrenergic receptors. A significant number of infected cells (25%) did not respond to the agonist. Two days after infection the cultures exhibited a higher frequency of spontaneous contractions (20%), paralleled by an increase in firing rate and a decrease in the action potential duration without significant changes in maximum diastolic potential and action potential amplitude. A decrease in alpha-adrenergic receptor-mediated positive chronotropic response to norepinephrine was also observed in 2-day infected cells. Cells made to phagocyte ferritin particles showed an increase in the rate of spontaneous contractions, but no changes in the positive chronotropic responses to norepinephrine. In conclusion, these observations show that during acute infection with T. cruzi, there are alterations in automaticity and in the chronotropic responses to norepinephrine, whose mechanisms are related to the process of parasite endocytosis by the cardiac cells.     

Red blood cell catechol O-methyl transferase and response to imipramine in unipolar depressive women

When baseline red blood cell catechol O-methyltransferase (COMT) was measured in 15 unipolar depressive women, the authors found a linear correlation between COMT and response to imipramine (best outcome occurring at low COMT). The results of this study were not related to such variables as intensity of depression, family history, or psychiatric history. The authors suggest that this assay may be useful either as a predictor of response to the drug or as a guide in choosing the optimum dose.     

The purine nucleotide cycle. Studies of ammonia production by skeletal muscle in situ and in perfused preparations

Ammonia production by hind limbs of rat was studied in perfused preparations during rest, exercise, and hypoxia, and while the perfusate contained epinephrine or cyanide. Ammonia production by hind limbs was also studied in situ during rest and exercise. Strong correlations were observed between ammonia, IMP, and lactate formation. Adenylosuccinate was not present in detectable amounts in resting muscle (less than 1 nmol/g dry weight) but it appeared and rose sharply in exercising muscle, and then declined during recovery. The maximum found was about 18 nmol/g dry weight. When IMP accumulation exceeded 2.8 mumol/g dry weight, the formation of adenylosuccinate diminished, presumably because of an inhibition of adenylosuccinate synthetase by excess substrate. Exercise resulted in a greatly increased output of ammonia and a decreased output of alanine and glutamine. The tissue contents of aspartate and glutamate were decreased, while that of alanine was increased. The content of malate increased 3-fold during exercise. Epinephrine, hypoxia, and cyanide each caused an increased output of ammonia at the expense of the amino acid content of the tissue. These results provide evidence for the operation of the purine nucleotide cycle in skeletal muscle under various conditions that are associated with an increased rate of glycolysis.     

Anticonvulsant activity of enzyme inhibitors in rats

Three liver microsomal enzyme inhibitors, proadifen, 2,4-dichloro-6-phenylphenoxyethyldiethylamine, and 2,4-dichloro-6-phenylphenoxyethylamine, and a hepatotoxic agent, carbon tetrachloride, were tested for anticonvulsant activity in adult male albino rats using the maximal electroshock seizure technique. All four substances exhibited significant anticonvulsant activity 1 hr after intraperitoneal administration. This protection was absent when tested 24 hr later.     

Surgical treatment of lung abscesses in children

The authors report their clinical observations of 44 patients, aged from 2 months to 14 years, with acute pulmonary abscesses. As evidenced by the authors a roentgenological examination in dynamics is of great value in establishing the diagnosis of pulmonary abscess, since it makes possible to follow the destruction of lung tissues and the formation of cavities. For treatment of lung abscesses different methods were employed: toilet bronchoscopy with antibiotics perfusion, puncture and drainage of the abscess, in case of pulmonary hemorrhage a resection of the lung portion involved, the complex conservative therapy.