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Biomedical subjects

G Chew

Publications and source records attributed to G Chew.

13 recordsLinked to original sources
PubMed2002

Cockroach allergy and exposure to cockroach allergen in Polish children with asthma.

BACKGROUND: Asthma morbidity increases every year, especially among children, and exposure to high levels of indoor allergens is a very important factor. We evaluated the prevalence and exposure to cockroach (CR) allergen in asthmatic children in Poland, and also tested the hypothesis that asthma with allergy to CR is more severe than with allergy to other antigens. METHODS: One hundred and sixty children with asthma were examined, had skin prick tests (SPT) with common and CR allergens, underwent spirometry, and provocation tests to histamine. Children with positive SPT to CR had measured specific IgE levels to this antigen and Bla g 2 concentrations were measured in their homes. RESULTS: The most common allergen, was dust mite 51.3%, followed by pollen 48.8% and CR allergen 24.3%. In children with CR sensitivity, 13% had mild asthma, 26% moderate and 61% had severe asthma. Their levels for forced expiratory volume in one second (FEV1), and the provocative concentration of histamine that caused a 20% fall in FEV1 (PC20), were statistically lower than in the group of children with other than CR allergies. Bla g 2 antigen was detected in 55.13% samples. The highest levels of Bla g 2 were found in old houses, without central heating, and in houses with lower income. CONCLUSION: In Polish children, CR allergen is a very important factor of sensitivity. Concentrations of Bla g 2 in homes are higher than previously reported in other European countries, and are strongly related to the houses' characteristics. Also, children with CR hypersensitivity have severe asthma more often than children with other allergies.

Adolescent↗
PubMed2000

Acute lindane poisoning in three children.

Lindane has been reported to cause central nervous system (CNS) toxicity including seizures after prolonged dermal contact and also after acute ingestions. Despite safer alternatives, lindane still remains a commonly used agent in the treatment of scabies and pediculosis. We present three cases of acute toxicity after the inadvertent oral administration of lindane in three siblings. A 17-month-old female suffered a single seizure. A 3-year-old male was listless, nauseated, pale, and had decreased responsiveness to verbal and tactile stimulation. A 4-year-old female became nauseated and required bag-valve-mask ventilation for hypoventilation. The three patients all recovered without sequelae.

Acute Disease↗
PubMed2000

Socioeconomic predictors of high allergen levels in homes in the greater Boston area.

In the United States, childhood asthma morbidity and prevalence rates are the highest in less affluent urban minority communities. More than 80% of childhood asthmatics are allergic to one or more inhalant allergens. We evaluated whether socioeconomic status was associated with a differential in the levels and types of indoor home allergens. Dust samples for an ELISA allergen assay were collected from the homes of 499 families as part of a metropolitan Boston, Massachusetts, longitudinal birth cohort study of home allergens and asthma in children with a parental history of asthma or allergy. The proportion of homes with maximum home allergen levels in the highest category was 42% for dust mite allergen (> or = 10 microg/g Der p 1 or Der f 1), 13% for cockroach allergen (> or = 2 U/g Bla g 1 or Bla g 2), 26% for cat allergen (> or = 8 microg/g Fel d 1), and 20% for dog allergen (> or = 10 microg/g Can f 1). Homes in the high-poverty area (> 20% of the population below the poverty level) were more likely to have high cockroach allergen levels than homes in the low-poverty area [51 vs. 3%; OR, 33; 95% confidence interval (CI), 12-90], but less likely to have high levels of dust mite allergen (16 vs. 53%; OR, 0.2; CI, 0.1-0.4). Lower family income, less maternal education, and race/ethnicity (black or Hispanic vs. white) were also associated with a lower risk of high dust mite levels and a greater risk of high cockroach allergen levels. Within a single U.S. metropolitan area we found marked between-community differences in the types of allergens present in the home, but not necessarily in the overall burden of allergen exposure.

Adult↗
PubMed1998

The effect of serial dilution error on calibration inference in immunoassay.

A common practice in immunoassay is the use of sequential dilutions of an initial stock solution of the antigen of interest to obtain standard samples in a desired concentration range. Nonlinear, heteroscedastic regression models are a common framework for analysis, and the usual methods for fitting the model assume that measured responses on the standards are independent. However, the dilution procedure introduces a propagation of random measurement error that may invalidate this assumption. We demonstrate that failure to account for serial dilution error in calibration inference on unknown samples leads to serious inaccuracy of assessments of assay precision such as confidence intervals and precision profiles. Techniques for taking serial dilution error into account based on data from multiple assay runs are discussed and are shown to yield valid calibration inferences.

Algorithms↗
PubMed1996

Defecation induced deep venous thrombosis. A case report.

While the risk of deep venous thrombosis (DVT) during prolonged fights is well recognized, we present the case of a 54-year-old male who suffered a deep venous thrombosis following defecation. Defecation, through a combination of the Valsalva maneuver and squatting, led to a DVT due to venous stasis, most marked in the left leg. Color-duplex scanning not only proved a convenient diagnostic tool but also allowed for monitoring and documentation of popliteal and saphenous vein recanalization. Being non-invasive and complication-free, color-duplex scanning should be considered for any patient in whom DVT is a possibility.

Angiography↗
PubMed1994

Annexins possess functionally distinguishable Ca2+ and phospholipid binding domains.

All annexins bind Ca2+ and phospholipids, although individual annexins differ markedly in their affinities for these ligands. Annexin I binds phosphatidylserine (PS) at lower [Ca2+] than annexin V, while annexin V exhibits a higher affinity for PS than does annexin I. To identify the structural determinants of these properties, we characterized a series of chimeric annexins. A chimera containing repeat 1 of annexin V used to repeats 2, 3, and 4 of annexin I exhibited a Ca2+ requirement for PS binding close to that of annexin I, while chimeras containing repeat 1 of annexin I fused to repeats 2, 3, and 4 of annexin V required higher [Ca2+], similar to that of annexin V. In contrast, the overall affinity for PS vesicles was determined by the source of repeat 1. The chimera that contained repeat 1 of annexin V exhibited a high affinity for PS, while a chimera that contained repeat 1 of annexin I had a low affinity for PS similar to that of annexin I. We conclude that the [Ca2+] requirement for phospholipid binding and the overall phospholipid affinity of annexins are determined by distinct domains.

Annexins↗
PubMed1990

Fed, but not fasted, adrenalectomized rats survive the stress of hemorrhage and hypovolemia.

We have recently shown that conscious adrenalectomized rats exhibit nearly normal recovery of arterial blood pressure during the 5 h after hemorrhage. In those experiments, it appeared that a previous reduction in food intake might have compromised the recovery of blood pressure and increased mortality. These experiments were designed to test in conscious sham-adrenalectomized (control) and adrenalectomized rats prepared with indwelling arterial and venous cannulae 1) the effects of a 20- to 24-h fast (compared to rats fed ab libitum) on the mobilization of plasma substrates and recovery of arterial blood pressure after a 15 ml/kg.5 min hemorrhage, and 2) vascular responsivity to pressor agents in fed or fasted groups before or 2 h after hemorrhage. In all rats hemorrhage resulted in decreased arterial pressure and heart rate. Arterial pressure recovered to near normal in both fed and fasted control groups and in the fed adrenalectomized rats, and all of these rats survived for 24 h after stress. By contrast, in the fasted adrenalectomized rats, arterial pressure recovered only during the first 1.5-2 h and then failed, resulting in 100% mortality by 3-5 h. Compared to the other three groups, in which substrate levels either increased or remained fairly stable, plasma glucose and beta-hydroxybutyrate concentrations fell steadily from 1.5-2 h after hemorrhage until death occurred in the fasted adrenalectomized rats. Basal ACTH concentrations were elevated compared to control values in both adrenalectomized groups (fed and fasted). Hemorrhage caused increases in plasma ACTH in all groups; the magnitude of the responses did not differ among the groups. The dilution of Evans' blue dye after hemorrhage (used as an index of fluid movement into the vascular space) was not different in control and adrenalectomized rats (either fed or fasted). There were no differences in pressor responses to phenylephrine, vasopressin, or angiotensin-II between the fed and fasted conditions in the control rats either before or after hemorrhage. There was a fasting-associated decrease in vascular responsivity to vasopressin, but normal responsivity to phenylephrine and angiotensin-II, in the adrenalectomized rats both before and after hemorrhage.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenalectomy↗
PubMed1990

Corticosterone, but not glucose, treatment enables fasted adrenalectomized rats to survive moderate hemorrhage.

Fed adrenalectomized rats survive the stress of hemorrhage and hypovolemia, whereas fasted adrenalectomized rats become hypotensive and hypoglycemic after the first 90 min and die within 4 h. We have studied the effects of glucose and corticosterone (B) infusions after hemorrhage as well as treatment with B at the time of adrenalectomy on the capacity of chronically prepared, conscious, fasted, adrenalectomized rats to survive hemorrhage. We have also measured the magnitudes of vasoactive hormone responses to hemorrhage. Maintenance of plasma glucose concentrations did not sustain life; however, treatment of rats at the time of adrenalectomy with B allowed 100% survival, and acute treatment of adrenalectomized rats at the time of hemorrhage allowed about 50% survival during the 5-h posthemorrhage observation period. Rats in the acute B infusion group that died exhibited significantly increased plasma B and significantly decreased plasma glucose concentrations by 2 h compared to the rats that lived. Plasma vasopressin, renin, and norepinephrine responses to hemorrhage were markedly augmented in the adrenalectomized rats not treated with B, and plasma vasopressin concentrations were significantly elevated at 1 and 2 h in all of the rats that subsequently died compared to values in those that lived. We conclude that: 1) death after hemorrhage in fasted adrenalectomized rats is not a result of lack of glucose; 2) chronic and, to an extent, acute treatment of fasted adrenalectomized rats with B enables survival; 3) fasted adrenalectomized rats exhibit strong evidence of hepatic insufficiency which is not apparent in either fed adrenalectomized rats or B-treated fasted adrenalectomized rats; 4) death after hemorrhage in fasted adrenalectomized rats may result from hepatic failure as a consequence of marked splanchnic vasoconstriction mediated by the actions of extraordinarily high levels of vasoactive hormones after hemorrhage; and 5) B appears to act to decrease the magnitude of response of vasoactive hormones after hemorrhage in fasted adrenalectomized rats.

Adrenalectomy↗
PubMed1975

Sensitivity test on Neisseria meningitidis strains to antimicrobial drugs.

1. The Authors present the antibiotic sensitivity pattern of 62 Neisseria meningitidis strains isolated in Northern Ghana (Bawku, Navrongo, Bolgatanga and Nalerigu) in February-March, 1973. The following antibiotics or chemotherapeutic drugs were effective in vitro: Penicillin 100%, Ampicillin 100%, Chloramphenicol 100%, Tetracycline 100%, Erythromycin 100% (Nalidixic acid 100%, Nitrofurantion 100%), and the following were less effective: Streptomycin 61.2%, Novobiocin 100% (weakly sensitive), Oleandomycin 95.1% (weakly sensitive), Septrin 87%, Sulphafurazole 91.9%, Sulphadiazine 91.9%. All the isolates were Colistin resistant. 2. The sex and age distribution of patients with positive culture for Neisseria meningitidis shows the preponderance of males over females and the dominance of the group of 5-15 years of age over the other age groups. These results are in good agreement with previous data collected in other countries of the "meningitis belt".

Adolescent↗