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Biomedical subjects

R Scott

Publications and source records attributed to R Scott.

At least 145 records · Page 8Linked to original sources
PubMed1993

Molecular pharmacology of the beta-adrenergic receptor on THP-1 cells.

The beta-adrenergic receptor, its occupancy and subsequent modulation of intracellular cAMP, and mRNA expression were characterized for the promonocytic leukemia cell line THP-1. We report that THP-1 cells appear to express a beta-1 receptor with a Kd of 1.8 +/- 0.3 x 10(-11) microM and a B max of 108 +/- 0.07 fmole/mg protein using 125I-iodocyanopindolol (125I-ICYP). The potency of various beta-adrenergic agonists to compete for the 125I-ICYP binding site followed the order: isoproterenol (0.8 microM) > dobutamine (2.1 microM) > salbutamol (3 microM) > epinephrine (3.8 microM) > soterenol (4.6 microM) > terbutaline (11.1 microM) > norepinephrine (13.8 microM). Occupancy of the beta receptor on THP-1 cells results in activation of adenyl cyclase suggesting that these cells have a functional beta-adrenergic receptor. This receptor also has specific immunoregulatory properties, reducing message levels for tumor necrosis factor--but not interleukin 1, following treatment with isoproterenol (approximate EC-50 of 0.01 microM). We conclude, based on the above criteria, that THP-1 cells express a beta-1 receptor which, following ligand binding, results in increased cAMP leading to downregulation of TNF expression.

Adenylyl Cyclases↗
PubMed1993

Exposure to violence among inner-city youth.

Interpersonal violence is a major cause of morbidity and mortality among adolescents and young adults. In this study, 246 inner city, predominantly black youth (ages 14-23 years) were surveyed regarding their exposure to, and participation in, violent acts. An in-depth psychological interview was also completed. A total of 44% reported they could access a gun within one day, 42% have seen someone shot or knifed, and 22% have seen someone killed. In the preceding 3 months, 18% reported carrying a gun, and 32% had been in a physical fight; 34 subjects were rated by the psychologists as a high risk for involvement in violent acts. Those subjects were more likely to be of lower socioeconomic status (p < 0.01) and to have been physically abused (p < 0.001) but no more likely to be a witness to violent events. Inner-city youth are frequently exposed to violence. Those at risk for perpetration of violence were more likely to be at high risk for most other health-risk behaviors.

Adolescent↗
PubMed1993

Quantitative grading of nerve fiber layer photographs.

PURPOSE: The authors have developed a simple method for semi-quantitative grading of atrophy of the peripapillary nerve fiber layer (NFL) in black and white photographs. METHODS: An experienced observer read sets of NFL photographs using a four-level grading system. Five observers with varying levels of experience at ophthalmic examination were taught the grading system in approximately 4 hours, and their readings were compared with those of the expert. RESULTS: The reproducibility of readings by an experienced observer was excellent. The validity of the grading system was confirmed by comparisons to visual field findings, as well as to cup-to-disc ratios in the same eyes. The agreement with the expert by the five trained graders was good. CONCLUSIONS: Grading of the NFL could be useful both to monitor development of early glaucoma damage clinically and to measure progression of glaucoma damage in clinical trials research. The grading system can be taught readily to other observers.

Adult↗
PubMed1993

The anther-specific protein encoded by the Brassica napus and Arabidopsis thaliana A6 gene displays similarity to beta-1,3-glucanases.

An anther-specific Brassica napus cDNA, A6, and two corresponding Arabidopsis thaliana genes have been isolated. Sequence analyses of A6 revealed similarity to beta-1,3-glucanases. The deduced A6 protein differs from other beta-1,3-glucanases in the possession of a long C-terminus. Immunoblotting using an antibody raised to the A6 protein detects a temporal 60 kDa protein in B. napus buds, suggesting that the long C-terminal region is present in the mature protein. A6 promoter-GUS and RNase fusions demonstrate that the A6 gene is tapetum-specific and temporally expressed with a peak in activity when the plant normally expresses callase (a complex of endo- and exo-beta-1,3-glucanase activities). The sequence similarity of A6 to other beta-1,3-glucanases, coupled with the temporal and spatial expression data, suggests that A6 may be part of the callase enzyme complex.

Amino Acid Sequence↗
PubMed1993

Isolation of an asparagus intracellular PR gene (AoPR1) wound-responsive promoter by the inverse polymerase chain reaction and its characterization in transgenic tobacco.

The Asparagus officinalis intracellular PR1 (AoPR1) gene is expressed in response to wounding and pathogen attack. We utilized the inverse polymerase chain reaction (IPCR) to isolate the cis-acting regulatory sequences of the AoPR1 gene following unsuccessful attempts to identify hybridizing clones in genomic libraries. Sequence analysis of two IPCR products revealed that a 347 bp intron was present in the AoPR1 gene and that it was probable that the AoPR1 regulatory sequence had been amplified. To test the AoPR1 cis-acting sequences for biological function a translational fusion was constructed with the beta-glucuronidase (GUS) reporter gene and tested in tobacco. These data demonstrated that sequences 982 bp from the probable start of transcription are sufficient to direct wound-inducible transcription and that there is no signal peptide encoded by the first 31 residues of the predicted AoPR1 protein. Histochemical localization of GUS activity in transgenic tobacco demonstrated strong activity localized to wound and pathogen invasion sites. GUS activity was also found in mature pollen grains.

Amino Acid Sequence↗
PubMed1993

Three-year changes in refraction and its components in youth-onset and early adult-onset myopia.

We compared refractive components, and their changes during a 3-year period, for 79 young adults of whom 29 were youth-onset myopes, 26 were early adult-onset myopes, and 24 were emmetropes. In the initial evaluation we found that mean corneal power was greater for both groups of myopes than for the emmetropes, whereas mean vitreous chamber depth and mean axial length were greater for the youth-onset myopes than for the other two refractive error groups. However, the differences between the two groups of myopes appear to be related to the fact that the mean amount of myopia was significantly greater for the youth-onset myopes than for the early adult-onset myopes. During the 3-year period, mean spherical equivalent refraction for subjects in all three refractive error groups changed in the direction of increasing myopia. For each of the three groups, the only refractive component changes having significant correlations with changes in refraction were vitreous chamber depth and axial length. We interpret these results as indicating that: (1) whether axial elongation occurs before, during, or after the completion of the normal growth period, the result is an eye whose cornea is significantly steeper, whose vitreous chamber depth and axial length are significantly greater, and whose lens differs little from that of an emmetropic eye of a person of the same age and (2) when myopia progresses with time, the progression is due to an increase in axial length that is not fully compensated by a decrease in lens power.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

T cell function in children with acute lymphoblastic leukaemia.

Modern intensive chemotherapy has dramatically improved the prognosis of acute lymphoblastic leukaemia (ALL) in children. However, once remission has been established, quality of life and even survival may be threatened by exacerbation of viral infections in the prolonged period of continuation therapy necessary to prevent relapse. Often the viruses involved in the most severe infections are from the herpesvirus and paramyxovirus groups, suggesting that patients suffer from a defect in the cellular immunity thought essential to control such cell-associated infections. This may result from a T cell defect and, in this study, T cell responsiveness of patients under therapy for leukaemia has been investigated. In vitro proliferative responses of peripheral blood leucocytes (PBL) to the T cell mitogen phytohaemagglutinin (PHA) were impaired in children with ALL before treatment and in the induction of remission. Impairment was attributable to reduced T cell numbers, the presence of inhibitors in the patient's serum and direct damage to lymphocytes. On achieving remission, proliferative responses to PHA of both CD4+ and CD8+ T cell subsets quickly returned to normal levels with the switch to continuation chemotherapy. Proliferative responses to Herpes simplex virus antigens were also apparently normal in the majority of patients tested in remission. Further investigations, however, have suggested a persisting defect in CD8+ lymphocyte function. Gamma interferon secretion by PHA-stimulated PBLs was severely reduced for children with ALL in remission when compared with control children of similar age. Further, cytotoxic T lymphocyte responses to allogeneic cells could only be induced in PBL isolated from two of 13 children in remission from ALL whilst all control children of similar age and adults produced anti-allogeneic responses.

Adolescent↗
PubMed1993

Structural model for emmetropic and myopic eyes.

A structural model for the eye was tested using refractive component data for 42 emmetropic eyes (-0.50 to +1.50 D) and 42 eyes having from 5.00 to 7.00 D of myopia. Parameter estimates derived by applying the structural model to emmetropic eyes and to myopic eyes demonstrated that a common model described the two types of eyes, but that emmetropic eyes and myopic eyes could be considered to belong to statistically discrete populations. Corneal radius and vitreous chamber depth were the most important components determining refractive state.

Adolescent↗
PubMed1993

Case report: malignant giant cell tumour of the pancreas presenting as a large pancreatic cyst.

Carcinoma of the pancreas is a common tumour. Histologically, the majority are adenocarcinomas of duct origin. Carcinomas of the pancreas containing giant cells are uncommon and those containing osteoclast-type tumour cells are very rare. We report a case of malignant giant cell tumour presenting as an extremely large, thin walled haemorrhagic cyst of the pancreas. This tumour is most unusual in that the wall is composed of multiple highly pleomorphic malignant-looking multinucleated giant cells as well as numerous osteoclast-like giant cells in a stroma of small spindle shaped mononuclear cells.

Giant Cell Tumors↗
PubMed1993

Factor analysis of the WAIS-R and Verbal Memory and Visual Memory Indices of the Wechsler Memory Scale--Revised, for a vocational rehabilitation sample.

Few empirical studies have examined factor structures of responses of vocationally impaired persons, and those studies have drawn only on aptitude scores (Wechsler Adult Intelligence Scale--Revised: WAIS--R). Results have been inconclusive as to whether a two- or three-factor solution is more appropriate. The present work examined the factor scores of a vocational rehabilitation sample of 54 adults who had been given the WAIS--R and the Verbal Memory and Visual Memory Indices of the Wechsler Memory Scale--Revised. Analysis indicated that combining data from the two tests yields a viable three-factor solution which may contribute to the refinement of intervention strategies for vocationally vulnerable adults.

Accidents, Occupational↗
PubMed1993

Informed decision making in persons acquitted not guilty by reason of insanity.

Deciding to raise an insanity defense carries serious consequences. This is especially true for persons charged with minor offenses, for whom an acquittal not guilty by reason of insanity (NGRI) might lead to a longer period of incarceration than would conviction. Before raising an insanity defense, a defendant should be provided with information necessary to make an informed decision and should be competent to understand the consequences of the verdict. This study attempted, through retrospective review and concurrent evaluation, to determine the degree to which trial courts in Virginia attended to these important aspects of informed decision making before finding defendants charged with misdemeanors NGRI. The study also attempted to assess the degree to which defendants were competent and informed at the time of adjudication. In most instances, trial courts did not consider defendants' competence to make decisions regarding the insanity defense and did not consider whether defendants were informed about the consequences of a successful insanity defense at the time of adjudication. The average length of stay for these patients was (at least) 21 months; most would have been released earlier had they been committed civilly rather than committed as a result of insanity pleas. We stress the need to educate judges, attorneys and forensic evaluators to the importance of considering defendants competence to plead insanity and of providing information about the consequences of a successful plea. We also propose that laws be changed to recognize the importance of these elements in the decision making process regarding pleas of insanity.

Adult↗
PubMed1993

Characterization of a new class of oleosins suggests a male gametophyte-specific lipid storage pathway.

The expression and sequences of two related antherspecific cDNAs (I3 and C98) of Brassica napus (oilseed rape) were examined. These cDNAs were found to exhibit significant predicted amino acid sequence similarity with a group of seed-specific proteins, the oleosins, which are involved in oil body membrane structure. Pollen of B. napus also contains oil bodies, and the synthesis and accumulation of these organelles correlates with expression of the I3 and C98 transcripts. The protein content of purified pollen oil bodies was therefore examined in order to determine the presence or absence of possible oleosins. One major protein species of 14 kDa was identified and subjected to N-terminal amino acid sequence determination. The sequence of this pollen oil body associated protein is homologous to the predicted sequence of one of the anther-specific cDNs, I3, implying that this cDNA represents an anther-specific oleosin gene expressed in developing pollen. The expression of other genes active during seed oil body formation was also examined, and these were found to be specific to the sporophyte, inferring the existence of specific components of the pathway of lipid synthesis and storage in the male gametophyte. These possibilities and the relationship between different oleosin genes are discussed.

Amino Acid Sequence↗
PubMed1993

Gametophytic and sporophytic expression of an anther-specific Arabidopsis thaliana gene.

Genomic and cDNA clones of the anther-specific APG gene from Arabidopsis thaliana and Brassica napus, which encodes a novel proline-rich protein, were isolated and characterized. Southern blotting and Northern analysis of male fertile and cytoplasmic male sterile varieties of B. napus showed that the APG gene is present as a single copy in the Arabidopsis genome, and that the B. napus APG gene is a member of a small anther-specific gene family. Analysis of developmentally staged B. napus flower buds indicated that APG transcript is confined to the anther during the period of microspore development. Reporter gene fusions established that the APG promoter directs expression in a number of cell types in anthers of transformed plants. This expression is consistent with the temporal pattern of mRNA accumulation in B. napus buds and follows a complex developmental pattern. Most significantly, the promoter is active in both sporophytic and gametophytic cell types, with activity of the transgene in each cell type being delineated by various cytological markers.

Amino Acid Sequence↗
PubMed1993

Artificial intelligence: its use in medical diagnosis.

In nuclear medicine, analysis, interpretation and diagnosis may each be appropriate as applications for ANNs. Image processing and pattern recognition are two application areas of ANN technology that appear promising. An ANN (21) was used to classify normal and abnormal FDG-PET scans and performed better than discriminant analysis. Favorable results have been obtained from an ANN (22) in the interpretation of data recorded by experienced observers using various standard V/Q scans to determine the likelihood of pulmonary embolism. Carver Mead's book (23) on the development of hardware neural systems defines new approaches to ANN fabrication, including an electronic 100,000 transistor retina. As hardware is developed to permit the design of very large networks, we may expect many useful imaging applications to emerge for ANNs in the medical field.

Artificial Intelligence↗
PubMed1992

Hereditary conditions in which the loss of heterozygosity may be important.

Somatic mutations are a common event in multicellular organisms and, therefore, have a significant impact on health. They can lead to either heterozygosity or homozygosity. Since the multistep concept of carcinogenesis presupposes that mutations/deletions of several genes are acquired, the identification and location of the critical genes involved in this sequence is attempted either by the observation of cytogenetic or molecular abnormalities in tumorous tissue or by linkage analysis, or both. The retinoblastoma paradigm of loss of heterozygosity with respect to the loss of the only wild-type allele can be applied to familial neoplasias occurring in all organs as they are summarized in this review. The development of homozygosity in non-malignant tissue has not been extensively investigated. However, its study has contributed to the identification of new genetic phenomena such as parental unidisomy and genomic imprinting.

Genetic Diseases, Inborn↗