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Biomedical subjects

J Howell

Publications and source records attributed to J Howell.

At least 37 records · Page 2Linked to original sources
PubMed1995

Children who are shot: a 30-year experience.

Three data sets describe the pattern of gunshot injuries to children from 1960 to 1993: The Harlem Hospital pediatric trauma registry (HHPTR), the northern Manhattan injury surveillance system (NMISS) a population-based study, and the National Pediatric Trauma Registry (NPTR). A small case-control study compares the characteristics of injured children with a control group. Before 1970 gunshot injuries to Harlem children were rare. In 1971 an initial rise in pediatric gunshot admissions occurred, and by 1988 pediatric gunshot injuries at Harlem Hospital had peaked at 33. Population-based data through NMISS showed that the gunshot rate for Central Harlem children 10 to 16 years of age rose from 64.6 per 100,000 in 1986 to 267.6 per 100,000 in 1987, a 400% increase. The case fatality for children admitted to Harlem Hospital (1960 to 1993) was 3%, usually because of brain injury, but the majority of deaths occurred before hospitalization. During the same period, felony drug arrests in Harlem increased by 163%. The neighboring South Bronx experienced the same increase in gunshot wound admissions and felony arrests from 1986 to 1993. The NPTR showed a similar injury pattern for other communities in the United States. In a case-control analysis. Harlem adolescents who had sustained gunshot wounds were more likely to have dropped out of school, to have lived in a household without a biological parent, to have experienced parental death, and to have known of a relative or friend who had been shot than community adolescents treated for other medical or surgical problems.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Stereoselective epoxidation of 2,2-dimethyl-2H-1-benzopyran-6-carbonitrile.

The chiral intermediate (3S,4R)-trans-3,4-dihydro-3,4-dihydroxy-2,2-dimethyl- 2H-1-benzopyran-6-carbonitrile [(+)-trans diol 3] was made by the stereoselective microbial epoxidation of 2,2-dimethyl-2H-1-benzopyran-6-carbonitrile 1. This compound is a potential intermediate for the total synthesis of potassium-channel openers. Several microbial cultures were found which catalyzed the transformation of 1 to the corresponding (3S,4S)-epoxide 2 and (+)-trans diol 3. The two best cultures, Corynebacterium sp. SC 13876 and Mortierella ramanniana SC 13840 gave reaction yields of 32 M% and 67.5 M% and optical purities of 88 and 96%, respectively, for (+)-trans diol 3. A single-stage process (fermentation-epoxidation) for the biotransformation of 1 was developed using Corynebacterium sp. SC 13876 and M. ramanniana SC 13840. In a 25-L fermentor, the (+)-trans diol 3 was obtained in 38.6 M% yield with an optical purity of 90% using Corynebacterium SC 13876. The reaction yield of 60.7 M% and optical purity of 92.5% were obtained for (+)-trans diol 3 using M. ramanniana SC 13840. A two-stage process for the preparation of (+)-trans diol 3 was also developed using a 3 L cell-suspension (10% w/v, wet cells) of M. ramanniana SC 13840. The reaction was carried out in a 5-L Bioflo fermentor. The concentration of substrate 1 was 2 g L-1 with glucose present at 10 g L-1. After 48 h, (+)-trans diol 3 was obtained in 76 M% yield with an optical purity of 96%.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacteria↗
PubMed1994

Isolation of chicken anaemia virus from broiler chickens in New Zealand.

Chicken anaemia virus was isolated for the first time in New Zealand from the New Zealand domestic chicken population. The virus was recovered from diseased birds in five separate flocks of broiler chickens aged between 14 and 33 days of age. Six isolates were obtained from bone marrow and lymphoid tissues using the MDCC-MSB1 cell line derived from Marek's disease lymphoma. All isolates were resistant to chloroform and survived exposure to 70 degrees C for 5 minutes. The main clinical features consistently associated with the disease outbreaks were increased mortality, yolk sac infections, sub-cutaneous haemorrhages and atrophy of the thymus. Fungal pneumonia occurred in two flocks, and gangrenous dermatitis as a result of bacterial infection in another flock. Microscopic examination showed atrophy of the thymus, reduced medullary haematopoiesis and inflammation resulting from secondary infections.

Journal Article↗
PubMed1993

Hepatic tumors: role of computed tomographic arterial portography in surgical planning.

Various imaging modalities currently used to evaluate liver tumors include magnetic resonance imaging, ultrasonography, contrast-enhanced computed tomography, and computed tomographic arterial portography. In our review of 28 cases, we found CT arterial portography to be very sensitive, and in 5 of these 28 cases CT arterial portography was a key factor in altering the course of therapy.

Adult↗
PubMed1993

Microbial reduction of 1-(4-fluorophenyl)-4-[4-(5-fluoro-2-pyrimidinyl)-1- piperazinyl]butan-1-one.

Among various micro-organisms screened for the stereoselective reduction of 4-chloro-1-(4-fluorophenyl)butan-1-one (1), Hansenula polymorpha [American Type Culture Collection (A.T.C.C.) 26012 and 86014], Nocardia salmonicolor [Squibb Culture (S.C.) 6370], Arthobacter simplex (A.T.C.C. 6949), Mycobacterium vaccae (A.T.C.C. 29678), Candida boidinii (A.T.C.C. 13821) and Saccharomyces cerevisiae (A.T.C.C. 13792) reduced compound 1 to the corresponding (R)-(+)-alcohol (2). In contrast, Lactobacillus kefir (A.T.C.C. 35411), Pullularia pullulans (A.T.C.C. 16623), Trigonopsis variabilis (A.T.C.C. 10679) and Cunninghamella echinulata (A.T.C.C. 26269) reduced compound 1 to the (S)-(-)-alcohol (2). When 1-(4-fluorophenyl)-4-(1-piperazinyl)butan-1-one (3) was used as substrate for the reduction, only Nocardia globerula (A.T.C.C. 12505) and Saccharomyces cerevisiae (A.T.C.C. 13792) converted compound 3 into the corresponding (R)-(+)-alcohol (4). Organisms which reduced compound 1 were inactive for the reduction of compound 3. 1-(4-Fluorophenyl)-4-[4-(5-fluoro-2- pyrimidinyl)butan-1-one (5) was reduced to the corresponding (R)-(+)-alcohol (6) by Mortierella ramanniana (A.T.C.C. 38191) and to the (S)-(-)-alcohol (6) by Pullularia pullulans (A.T.C.C. 16623). (R)-(+)-compound 2 and compound 4 are key chiral intermediates in the total chemical synthesis of (R)-(+)-compound 6, an effective antipsychotic agent under development at Bristol-Myers Squibb. A single-stage (fermentation/biotransformation) process and two-stage (fermentation and subsequent biotransformation by cell suspensions) process were developed for the stereoselective reduction of compound 5 to (R)-(+)-compound 6 by Mortierella ramanniana (A.T.C.C. 38191). In both processes, the reaction yield of 98% and the optical purity of 99.4% were obtained for (R)-(+)-compound 6. The enzyme which catalysed the reduction of compound 5 to (R)-(+)-compound 6 was purified to homogeneity. The purified protein consisted of a single polypeptide of 29 kDa.

Bacteria↗
PubMed1992

Anatomical asymmetries and functional laterality.

Anatomical and functional asymmetries were measured using MRI and dichotic, visual field and hand performance laterality tasks in 104 normal right- and left-handed male and female adults. Comprehensive linear and area measures showed consistently larger brains when handedness and language laterality were in the same direction. Right-handers with left cerebral dominance for dichotic listening and left-handers with right cerebral dominance had larger structures. Hand performance was the strongest functional laterality related to anatomical asymmetries. Left hemisphere dominance on this task was associated with larger right frontal and left occipital widths. Dichotic listening or visual field laterality alone was not associated with contralaterally larger temporal, parietal or occipital measurements. Left visual field dominance for reading, interacting with right-handedness, was associated with wider left parietal width. The complex associations between anatomical and functional asymmetries contribute to individual differences in cerebral organization. The demonstrated association of coincident hand performance and language laterality measures with larger anatomical structures may confer biological advantage. Morphometric analysis in vivo may have increasing importance in interpreting behaviour.

Adult↗
PubMed1990

Sex, handedness, and the morphometry of cerebral asymmetries on magnetic resonance imaging.

Cerebral morphometry of linear measurements and hemispheric, frontal, temporal and parietal areas on MRI of 104 normal adults was analyzed for sex and handedness and right-left differences. The right hemisphere was significantly larger across all groups, but the left frontal width and area was larger in left handers. MANOVA showed separate effects of hand and sex for linear measures; right-handers had larger right anterior frontal, and left parietal and occipital widths. Ratios of L - R/L + R eliminated sex differences related to overall brain size, however, a significant sex-by-hand interaction was shown by the parietal area ratios, indicating larger left side in right-handed males and left-handed females. A 3-dimensional 'torque' was postulated, where the upper and rostral portions of the hemispheres were larger on the right and the lower and caudal parts equal, or slightly larger on the left. The relationship of anatomical asymmetries, sex and handedness is multi-dimensional, and may explain some of the variability of normal cognitive functions and deficits after brain damage.

Adolescent↗
PubMed1989

Word recognition and orthographic context effects in a letter-by-letter reader.

The performance of letter-by-letter readers when attempting to decipher written material gives the impression that words fail to directly evoke any higher-level representation. As a consequence, spelling patterns appear to be treated perceptually as if they were a collection of random letters. We tested the hypothesis that words are no longer mapped onto orthographic descriptions by examining the ability of a letter-by-letter reader to identify letters in familiar words, pseudowords, and random strings. A clear effect of orthographic context was obtained on the accuracy of letter recognition, indicating that spelling patterns do gain access to more central components of the reading mechanism. The implications of this result for our understanding of the syndrome are discussed.

Attention↗
PubMed1989

Hospital-based surveillance of malaria-related paediatric morbidity and mortality in Kinshasa, Zaire.

Although Plasmodium falciparum malaria is a leading cause of paediatric morbidity and mortality in Africa, few quantitative estimates are available about the impact of malaria on childhood health. To quantify the impact of the disease in an urban African setting, we reviewed the paediatric ward and mortuary records at Mama Yemo Hospital in Kinshasa, Zaire. From June 1985 to May 1986, 6208 children were admitted to the hospital, 2374 (38.2%) of whom had malaria; 500 of those with malaria died (case fatality rate, 21.1%). During this same period, there were 10,036 paediatric deaths, 1323 (13.2%) of which were attributed to malaria; 823 (62.2%) of these occurred in the emergency ward prior to hospitalization. Minimum population-based malaria mortality rates were highest for children aged less than 1 year (4.0 per 1000 per year). Over 70% of children admitted with malaria and greater than 80% of children who died from the disease were less than 5 years old. The total number of paediatric admissions and deaths remained relatively constant between 1982 and 1986; however, the proportional malaria admission rate increased from 29.5% in 1983 to 56.4% in 1986, and the proportional malaria mortality rate, from 4.8% in 1982 to 15.3% in 1986. These increases were temporally related to the emergence of chloroquine-resistant Plasmodium falciparum malaria in Kinshasa. Malaria is therefore a major cause of paediatric morbidity and mortality in the city, and this study indicates that hospital-based surveillance may be useful in monitoring disease-specific morbidity and mortality elsewhere in Africa.

Adolescent↗
PubMed1988

Hematometra presenting as acute appendicitis: a case report.

A case of intrauterine blood passing into the abdominal cavity and resulting in a clinical picture similar to acute appendicitis is presented. To our knowledge, hematometra presenting in this manner has not been reported in the medical literature. Some disease processes which more commonly mimic acute appendicitis include nonspecific mesenteric adenitis, gynecologic disorders, diverticulitis, and urinary tract infection. Unusual diseases presenting in this manner include splenic torsion, infarcted omentum, ileocecal tuberculosis, and duodenal hematoma.

Abdomen, Acute↗