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Biomedical subjects

M Derrick

Publications and source records attributed to M Derrick.

At least 19 recordsLinked to original sources
PubMed2001

Hypoxia-ischemia in fetal rabbit brain increases reactive nitrogen species production: quantitative estimation of nitrotyrosine.

Reactive nitrogen species (RNS) cause nitration of protein-bound tyrosine that is used as biomarker for detection. We hypothesized that RNS are formed in fetal rabbit brain following acute placental insufficiency. Near-term pregnant rabbits were randomized to either repetitive uterine ischemia or no ischemia, and fetal brains obtained. Only one electrochemical HPLC method (of three tested) was successful in detecting brain nitrotyrosine. Protein nitrotyrosine was significantly increased following cumulative 40 min ischemia and 20 min reperfusion compared to controls. Repetitive hypoxia-ischemia results in the increased formation of RNS in near-term fetal brains.

Animals↗
PubMed2001

The in vitro fate of rabbit fetal brain cells after acute in vivo hypoxia.

In the investigation of ischemia-induced brain damage, traditional methods using histopathology estimate brain cell death at a time remote from ischemic insult. These observations fail to take into account endogenous repair processes or ongoing injury cascades like apoptosis. The cells that are injured but not killed initially are the population most amenable to rescue. The hypothesis was that in vivo uterine ischemia-reperfusion would result in more cell death and apoptosis in fetal brain cells cultured in vitro. Near-term, 29 d gestation, pregnant New Zealand White rabbits were subjected to repetitive uterine ischemia for a cumulative time of 40 min ischemia and 20 min reperfusion. Immediately after uterine ischemia, the fetal brains were removed and dissociated into a cell suspension. The ischemic group had more cell death than non-ischemic controls as assessed by Trypan Blue exclusion and propidium iodide (PI) uptake on a flow cytometer. Aliquots of cells were plated and cultured for 24 and 48 hr. The ischemic group had significantly more cell death (propidium iodide) than non-ischemic controls at 24 hr and significantly more apoptosis, as assessed by annexin-V binding in cells at 24 hr and caspase-3 activity at 48 hr. Fewer cells attached to the culture plates at 48 hr in the ischemia group. After uterine ischemia, certain fetal brain cells die immediately, and other cells undergo ongoing damage resulting in necrosis and apoptosis that is manifest later. This method offers insight into the fate of those cells and provides a tool for assessing interventions to decrease cell injury.

Acute Disease↗
PubMed1998

Structure and properties of surfactant protein B.

Surfactant protein B is a small homodimeric protein that is found tightly associated with surfactant lipids in the alveolar space. In this review, we discuss the actions of SP-B on phospholipid membranes using information predominantly obtained from model membrane systems. We try to correlate these model actions with current concepts of SP-B structure and proposed biological functions. These functions may include critical roles in the intracellular assembly of surfactant through a role in lamellar body organogenesis, the structural rearrangement of secreted surfactant lipids into tubular myelin, and the subsequent rapid insertion of secreted surfactant phospholipids into the surface film itself. The relevance of SP-B to human biology is emphasized by the fatal respiratory distress that is associated with a genetic deficiency of SP-B and the important role of SP-B in certain exogenous surfactant formulations in wide clinical use.

Lipid Bilayers↗
PubMed1997

Relation of maternal ethnicity to infant birthweight in east London, England.

OBJECTIVE: We sought to determine whether black race is a risk factor for very low birthweight in a developed country other than the United States. DESIGN: A cross-sectional study was performed. SETTING: We analyzed a dataset of 1987-1990 birth records from three hospitals in East London, England. PARTICIPANTS: All live born African (N = 3,495), West Indian (N = 3,471), and European white (N = 20,313) singleton infants born to East London residents. MAIN OUTCOME MEASURES: For each ethnic group, we calculated the proportion of very low birthweight (< 1500g) and moderately low birthweight (1500-2499g) infants. RESULTS: The very low birthweight rate was 2.9% for infants of West Indian descent and 2.2% for infants of African descent vs. 1.3% for European whites; odds ratio (95% confidence interval) = 2.1(1.7-2.8) and 1.8(1.2-3.1), respectively. West Indian and white mothers were similar in terms of age, social support, and prenatal care. African mothers were older and had less social support. The West Indian:white and African:white differentials in very low birthweight rates persisted among low risk mothers; odds ratio (95% confidence interval) = 2.7(1.7-4.0) and 2.3(1.5-3.6), respectively. CONCLUSIONS: We conclude that black race is a risk factor for very low birthweight in the United Kingdom.

Adult↗
PubMed1988

Biochemical and cytogenetic studies of human lung cancers.

In ongoing studies, we have tested resected lung cancers from 41 men and 49 women; of those with primary lung cancer, 46 patients are free of disease and 35 have died of cancer or have persistent disease. Measurements and studies were as follows: total cellular deoxyribonucleic acid content by image analysis (n = 77); total genomic deoxyribonucleic acid methylation state and banding patterns from probed Southern blots (n = 36); radioimmunoassay for motilin, bombesin, gastrin, vasoactive intestinal peptide, and cholecystokinin (n = 18); and cytogenetic analysis (n = 39). All lung cancers were hyperploid. Adenocarcinomas and epidermoid carcinomas were generally hexaploid to nearly septaploid; comparisons by stage and histologic features suggested potential prognostic correlations. There was general hypomethylation of deoxyribonucleic acid (p less than 0.001). Deoxyribonucleic acid digests from restriction endonuclease Hpa II, when probed with deoxyribonucleic acid homologous to KPN, showed banding patterns that separated histologically indistinguishable primary adenocarcinomas and metastatic adenocarcinomas from one another. Cancers studied with radioimmunoassay were all negative for polypeptide hormones. Five cancers grew adequately in vitro to permit study of 190 detailed karyotypes (20 to 50 per tumor). Chromosome modal numbers ranged from 49 to 109. There were from 4 to 20 clearly abnormal marker chromosomes per tumor; abnormality derived from chromosome 1 was prevalent. Ten of 19 tumors xenotransplanted to nude mice were carried through two to five transplant generations without a change in histologic patterns.

Animals↗