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Biomedical subjects

A Gabriel

Publications and source records attributed to A Gabriel.

At least 127 records · Page 7Linked to original sources
PubMed1990

The relationship between carcass characteristics, plasma hormones and metabolites in young fattening bulls.

Six Belgian Blue bulls (double-muscled type) and six Friesian bulls were offered a fattening diet for 34 weeks. Plasma samples were obtained once a week and also every 20 min over a 24 h period, 7 weeks before slaughter. No differences were observed between the breeds in plasma glucose, urea and free amino nitrogen concentrations, while creatinine was significantly higher in the Belgian Blue bulls. Tri-iodothyronin, tetra-iodothyronin, insulin-like growth factor 1, insulin and testosterone concentrations were higher in the Holstein group. In contrast, the Belgian Blue bulls appeared to produce more growth hormone. The slaughter weight, carcass weight, dressing percentage and proportion of lean meat were significantly higher in the Belgian Blue group. The characteristics of muscle mass (carcass weight, dressing percentage and proportion of lean meat) were positively correlated with creatinine and with the total peak area or peak amplitude of growth hormone. The insulin concentration was positively correlated with the proportion of adipose tissue in the carcass and negatively correlated with the proportion of muscle. There were no correlations between the carcass characteristics and insulin-like growth factor 1 or testosterone. No further information was provided when the ratios of the hormones were correlated with carcass characteristics.

Age Factors↗
PubMed1990

Effects of 5-azacytidine in Syrian golden hamsters: toxicity, tumorigenicity, and differential modulation of bronchial carcinogenesis.

5-Azacytidine (AZC) was studied in a lung cancer model in outbred and syngeneic (F1D) hamsters wherein benzol[a]pyrene (BP) from sustained release implants (SRI) induces preneoplastic mucosal changes which progress to bronchogenic cancer. In pilot studies to evaluate AZC toxicity, a dose schedule of 5 mg/kg biweekly was found suitable and was then used for long-term administration in all subsequent studies. Three groups of outbred hamsters were studied: BP SRi alone (n = 60), BP SRI + AZC (n = 60), and AZC alone (n = 54). AZC treatment was begun 3-5 days after SRI placement. Sixty-one days after the start of the experiment, seven or eight hamsters were sacrificed from each group. Later sacrifices were at 3-week intervals in groups receiving BP SRI and at 6-week intervals in the AZC only group. Four groups of F1D syngeneic hamsters were studied: BP SRI alone (n = 50); BP + AZC starting 3-5 days after SRI placement and continuing until death (n = 52); BP + AZC from 3 to 5 days until 75 days after SRI placement (n = 49); BP + AZC starting 80 days after SRI placement and continuing until death (n = 52). Hamsters (n = 9-14) from each group were sacrificed at 120, 150, 180, and 220 days after SRI implantation. AZC alone was not carcinogenic under these conditions. Both outbred and F1D hamsters treated with early or continuous AZC had slower rates of neoplastic change from BP SRI than did animals receiving BP SRIs alone or BP + late AZC. The incidence of epidermoid cancer were the same for all regimens, but the tumors in those receiving AZC early in carcinogenesis were smaller than in those receiving late or no AZC. The incidences of nonepidermoid cancer were lower in those receiving AZC during early carcinogenesis, and larger tumors were noted in the absence of AZC. Thus, within the study period in this unique hamster lung cancer model, AZC given early in carcinogenesis inhibited only the later (promotional) phase of BP epidermoid carcinogenesis, but inhibited all phases of nonsquamous cancer development induced by BP. This differential modulation of bronchial carcinogenesis, which occurs from AZC given during preneoplastic stages, may prove useful for delineating molecular mechanisms underlying specific phenotypic types of bronchogenic cancers.

Animals↗
PubMed1990

A rapidly rearranging retrotransposon within the miniexon gene locus of Crithidia fasciculata.

The tandemly arrayed miniexon genes of the trypanosomatid Crithidia fasciculata are interrupted at specific sites by multiple copies of an inserted element. The element, termed Crithidia retrotransposable element 1 (CRE1), is flanked by 29-base-pair target site duplications and contains a long 3'-terminal poly(dA) stretch. A single 1,140-codon reading frame is similar in sequence to the integrase and reverse transcriptase regions of retroviral pol polyproteins. Cloned lines derived from a stock of C. fasciculata have unique arrangements of CRE1s. In different cloned lines, CRE1s, in association with miniexon genes, are located on multiple chromosomes. By examining the arrangement of CRE1s in subclones, we estimate that the element rearranges at a rate of ca. 1% per generation. These results indicate that the C. fasciculata miniexon locus is the target for a novel retrotransposon.

Amino Acid Sequence↗
PubMed1990

Animal performance, plasma hormones and metabolites in Holstein and Belgian Blue growing-fattening bulls.

Six Holstein (light-muscled type) and six Belgian Blue bulls (double-muscled type) were fed a finishing diet. Average daily gain was 1.36 kg for the Holstein bulls vs 1.24 kg for the Belgian Blue bulls (P less than .05). Holstein bulls consumed more feed (2.3 vs 1.8 kg/100 kg body weight, P less than .001) than the Belgian Blue bulls. The dressing percentage (55.4 vs 65.8%, P less than .001) and the proportion of muscle (56.1 vs 71.3%, P less than .001) in the carcass were less, whereas the proportions of adipose tissue (28.3 vs 15.4%, P less than .001) and bone (15.7 vs 13.4%, P less than .05) were higher in the Holstein bulls. Plasma creatinine determined in samples obtained once a week was lower (11.0 vs 20.3 mg/liter, P less than .001) in the Holstein bulls. In contrast, Holstein bulls tended to produce more triiodothyronine (2.3 vs 1.8 nM, P less than .10), tetraiodothyronine (71.9 vs 54.7 nM, P less than .10) and insulin-like growth factor I (IGF-I; 340 vs 205 ng/ml, P less than .20) than the Belgian Blue bulls. Growth hormone, insulin, IGF-I and testosterone were measured at 20-min intervals during two 24-h periods. In wk 6, Holstein bulls tended to produce more growth hormone than the Belgian Blues, as indicated by higher total peak area (3,185 vs 2,431 ng), peak amplitude (34.1 vs 22.6 ng/ml, P less than .10) and baseline (4.6 vs 3.3 ng/ml, P less than .20). In wk 27, the trends were opposite.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1990

Quantitative DNA alterations during 5-azacytidine-induced differential modulation of benzo(a)pyrene carcinogenesis in hamster bronchi.

Sustained release implants (SRI) containing 10% benzo(a)pyrene (BP) were placed endobronchially into outbred and syngeneic (F1D) hamsters. Randomly selected OB and F1D hamsters also received 5-azacytidine (AZC), 5 mg/kg i.p., twice weekly until death (AZC-CONT); two more groups of F1D hamsters were given the same AZC dose either for the first 75 days of SRI implantation (AZC-EARLY) or from 80 days after SRI placement until death (AZC-LATE). OB Hamsters were sacrificed at regular intervals from 62 to 189 days of SRI exposure. F1D Hamsters were sacrificed in groups after 120, 150, 180, and 220 days of SRI exposure. The bronchial mucosa at the SRI site was examined cytologically and histologically, as were the tumors that developed. Mean quantitative total cellular DNA values (QDNA) were measured by image analysis. For both varieties of hamster given AZC, QDNA values were higher in early carcinogenesis (CG) and lower in the late stage of CG than in hamsters that did not get AZC (P less than 0.001). QDNA values were lower in epidermoid than in non-epidermoid cancers (P less than 0.001); for both types of cancer, QDNA was lower in AZC-treated hamsters (P less than 0.01). Cancers induced under the influence of AZC included more epidermoid cancers (P less than 0.01) and were of a higher degree of differentiation (P less than 0.01) than those induced by BP alone, especially when AZC was given early in CG. There was no consistent relationship between QDNA and degree of differentiation in tumors. These differential effects of AZC given early during CG suggest that 1) for epidermoid bronchial CG, some of the molecular alterations involved in hyperploidy and in differentiation occur early in the sequential progression of carcinogenesis; and 2) for both epidermoid and non-epidermoid bronchial CG, the necessary changes must occur in a fixed sequence instead of as random events, until all needed changes have occurred.

Animals↗
PubMed1989

Isolation of colonic crypts that maintain structural and metabolic viability in vitro.

The aim of this study was to develop a method by which colonic epithelial cells can be isolated from resected mucosa or colonoscopic biopsy specimens and viability maintained in the short term. The principles of the technique are to digest the lamina propria from the epithelium with Dispase and collagenase, to disrupt the epithelium by trituration, and to purify the epithelial cells by seiving and differential sedimentation. Whole and partial crypts were isolated with consistently high purity of 93.5% +/- 1.2% (excluding red cells). Structural integrity was confirmed by light and electron microscopy, exclusion of trypan blue, minimal leakage of lactic dehydrogenase over 5 h (4.1% +/- 1.7%), and 51Cr leakage of less than 2% per hour over 16 h. Functional integrity was supported by continued deoxyribonucleic acid synthesis [( 3H]thymidine uptake) over 16 h and the formation of epithelial monolayer cultures on plastic. Thus, this simple method yields a highly enriched cell population that maintains high viability in vitro for at least 16 h. Such cells may be useful for the study of the biology of colonic epithelial cells.

Autoradiography↗
PubMed1989

A new case of deletion 1q42 syndrome.

We report a 1 8/12-year-old male with a de novo deletion of 1q42. The case is compared with 23 others from the literature. The clinical manifestations of our patient correspond with the phenotype of previous reports.

Chromosome Deletion↗
PubMed1989

[Primary lung cancer from biopsy material of the Pathomorphology Department of the Silesian Medical Academy in Zabrze].

An analysis was carried out of material biopsied during fiberoptic bronchoscopic examination of 289 patients suspected of lung malignant disorders were present more often in males. In the group of patients older than 40 years the most often diagnosed malignant process was squamous cell carcinoma. A high correlation of clinical suspicion of malignant process and histopathological diagnosis was found. A low rate of diagnosis of operable cases was found.

Adult↗
PubMed1987

Evidence of discontinuous transcription in the trypanosomatid Crithidia fasciculata.

In an effort to exploit the advantages of Crithidia fasciculata for detailed analysis of the mechanisms of discontinuous transcription in the trypanosomatid family, we have cloned, sequenced, and characterized the mini-exon gene repeat in Crithidia and mapped the termini of its primary transcript. We find that Crithidia contains approximately 500 mini-exon genes, present almost exclusively as tandemly repeated arrays on a single chromosome. Transcripts derived from these genes are approximately 90 bases in length with heterogeneity at both the 5' and 3' ends. Primer extension experiments reveal a putative splicing intermediate. Specific inhibition of in vitro translation of Crithidia mRNAs by an oligonucleotide complementary to the mini-exon suggests that all Crithidia mRNAs contain the mini-exon at their 5' termini. Comparison of mini-exon gene sequences from various trypanosomatids reveals several regions of conservation that imply functional constraints on the transcription of mini-exon genes and the processing of their transcripts.

Animals↗
PubMed1987

Differential susceptibility to bronchial carcinogenesis in syngeneic hamsters.

Previous studies of chemical carcinogenesis in the lung of Syrian golden hamsters have utilized outbred (nonsyngeneic) animals. Using the endobronchial sustained release implant technique, which causes focally originating cancers in outbred hamsters, we studied the course of bronchial carcinogenesis in two varieties of syngeneic Syrian golden hamsters, the LSH and the F1D strains (BIO 15.16 male X BIO 87.20 female). With either 10% benzo(a)pyrene or 10% methylcholanthrene sustained release implants the time course of epithelial transition from normal to neoplastic was the same for F1D hamsters as previously described for outbred hamsters. Using 10% benzo(a)pyrene sustained release implants the incidence of cancers as a function of time was significantly lower (P less than 0.001) in LSH hamsters as compared to outbred and F1D animals. Of 19 tumors transplanted into syngeneic F1D hamsters, 16 have been successfully propagated by serial transplantation. We conclude that (a) F1D hamsters are comparable to outbred animals in the response of their bronchial epithelium to endobronchial benzo(a)pyrene and methylcholanthrene, (b) there are significant differences in susceptibility to bronchial chemical carcinogenesis among hamster strains, thereby giving opportunity to study potential genetic control mechanisms during bronchial carcinogenesis, and (c) F1D hamsters are suitable for studies of lung cancer biology using tumor transplantation methods.

Animals↗
PubMed1987

A new colon carcinoma cell line (LIM1863) that grows as organoids with spontaneous differentiation into crypt-like structures in vitro.

A new colon carcinoma cell line (LIM1863) has been characterized. This cell line is unique in that the culture consists of organoids which are morphologically and functionally organized. Histological studies of the organoids show that the cells are arranged around a central lumen and the nuclei are polarized to the periphery. Two major morphological types are present: a columnar cell with a polarized, structurally normal brush border and goblet cells. The cells are also functionally mature and express the brush border enzymes aminopeptidase N, dipeptidyl peptidase IV, alkaline phosphatase, and sucrase-isomaltase. These enzymes are localized to the luminal membrane and the apical cytoplasm (of some cells). The goblet cells contain mucus and this mucus is secreted into the lumen. This functional differentiation suggests that the organoids contain precursor cells capable of differentiating along both the columnar and goblet cell pathways. At present no endocrine cells have been detected by morphological or histochemical analysis. The organoids have been in continuous culture with regular passaging for 21 months and also grow and differentiate normally in serum-free medium.

Aged↗
PubMed1986

Cultural values and biomedical knowledge: choices in infant feeding. Analysis of a survey.

This paper presents a study of 313 parturient women and considers their choices to bottle or breast feed. It examines demographic and cultural factors statistically and focuses on the effect of knowledge or ignorance of benefits of either method of infant feeding. Most women are found to have some biomedical knowledge of the benefits of breast feeding. The choice of bottle or breast feeding is closely associated with several demographic factors and a number of cultural ideas. Women who bottle feed see some of their dietary and other health related practices as barriers to breast feeding. It recommends that health practitioners who decide that individual women and/or their infants may benefit from breast feeding, should engage in a dialogue with the women. Such a dialogue should focus, not so much on information, but on the woman's views about her dietary and other health practices. If the woman is given compelling health reasons she may see herself as capable of changing some practices long enough to breast feed.

Adolescent↗
PubMed1986

Intensity increases of actin layer-lines on activation of the Limulus muscle.

Small angle x-ray diffraction patterns were recorded from isometrically contracting Limulus (horseshoe crab) telson levator muscle using a multiwire proportional-area detector on the storage ring DORIS. In the pattern a substantial increase in intensity is observed on the thin-filament-associated layer-line at 1/38 nm-1 (the first actin layer-line) with a maximum increase at a radial spacing of R = 0.07 nm-1 but there is a much smaller change in the intensity of the 5.9-nm layer-line, which also arises from the thin filament structure. The results suggest that during contraction the myosin heads, presumably being attached to the thin filaments, are arranged along the long-stranded helical tracks of the thin filaments but that the spatial relationship between the heads and the actin monomers varies. Intensity increases have also been observed (Maéda et al., manuscript in preparation) in the part of the patterns from frog muscle and barnacle muscle, which are attributable to the first actin layer-line. It is thus likely that the intensity increase of the first actin layer-line on the Limulus pattern is associated not with structural features which are special to Limulus muscle, but with the tension generating processes that are shared by muscles in general.

Actin Cytoskeleton↗
PubMed1985

Utilization and morbidity: random or tandem?

Earlier studies have shown that one in eight children persist in being high users of health care services over long periods of time and, conversely, about the same proportion of children are consistently low users. As these studies failed to discover reasons for these persistent deviations from average, this study explored three possible explanations: persistent morbidity, mental health problem, and familial patterns of use. Although all three phenomena were associated with both persistence of high utilization of services as well as an overall large number of visits, the number of types of morbidity was the most significant correlate of high use. Children who were constantly low users of services were much more likely to have only a few types of morbidity whereas children who were constantly high users were much more likely to experience a wide variety of types of problems. These findings suggest that an understanding of the demand for health services requires an understanding of the interrelationships of illnesses within individuals rather than a focus on particular illnesses or particular types of illnesses.

Acute Disease↗
PubMed1984

Morbidity in childhood--a longitudinal view.

We examined all the morbidity experienced in a six-year period by a total of 2591 children who were continuously enrolled in a prepaid medical plan. The children had received 19,291 diagnoses, each of which was assigned to one of 14 types of morbidity, and the frequency of each type was determined. Although the typical child had at least one problem in 5 of the 14 types of morbidity in the six-year period, over 20 per cent of children had at least 8 different types of problems during that time. Children with a greater variety of acute problems and more frequent acute problems were also more likely to have nonacute problems during the six-year period. Conversely, children with nonacute problems had more acute problems than other children. Our findings indicate that morbidity, like use of health services, occurred in clusters in this population of children. Therefore, an understanding of the cause and projected outcome of morbidity among children will be incomplete if the focus is only on specific diseases or specific types of illnesses.

Adolescent↗
PubMed1984

Preventive care and overall use of services. Are they related?

The relationship between the use of services of children constantly enrolled in a prepaid group practice medical plan for six years and the completeness of their preventive care were examined. Children who were consistently low users of services were more likely to be lacking one or more components of standard preventive care, particularly general health assessments in older children and vision, hearing, and tuberculosis screening in younger children. Teenage children who were low users were at some risk of not receiving their tetanus-diphtheria immunization on time. The relationship between low use of services and incomplete preventive care persisted after controlling for the severity of morbidity, although children with more severe morbidity were somewhat less likely to be missing preventive care. Health facilities and practitioners should pay special attention to assessing the need for standard preventive care in children who are infrequent users of services.

Adolescent↗