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Biomedical subjects

J E Scott

Publications and source records attributed to J E Scott.

At least 55 records · Page 3Linked to original sources
PubMed1996

Is delayed surgery really better for congenital diaphragmatic hernia?: a prospective randomized clinical trial.

Delayed surgery has become widely accepted in the management of congenital diaphragmatic hernia after comparing outcomes only with historical retrospective controls. It was the aim of this study to compare early and delayed hernia repair in a randomized prospective clinical trial. Fifty-four infants were randomized to receive either early repair (within 4 hours of admission) or delayed repair (more than 24 hours after birth). The survival rate was higher for the delayed group (57% v 46%), but the difference was not significant (difference: -11; 95% confidence limits: -37.5, 15.5). There were no significant differences between the two groups with respect to length of hospital stay, ventilator dependency, or survival time. Recorded preoperative risk factors were similar for the two groups. Eight infants in the delayed repair group died without having undergone surgery. The optimum time for surgery still needs clarification.

Blood Gas Analysis↗
PubMed1996

Bovine interleukins 2 and 4 expressed in recombinant bovine herpesvirus 1 are biologically active secreted glycoproteins.

The open reading frames encoding bovine interleukin 2 (boIL-2) and bovine interleukin 4 (boIL-4) were integrated into the unique short segment of the genome of bovine herpesvirus 1 (BHV-1) and expressed under control of the murine cytomegalovirus (MCMV) immediate-early 1 (ie1) enhancer-promoter element or the MCMV early 1 (e1) promoter. Madin-Darby bovine kidney cells infected with the recombinant viruses secreted boIL-2 or boIL-4 into the culture medium. Secretion was inhibited by the presence of brefeldin A during the infection, indicating that export from the cells was dependent on a functional Golgi apparatus. Treatment of the secreted interleukins with N-glycosidase F reduced the apparent molecular mass of recombinant BHV-1-expressed boIL-2 from 22 kDa to 16 kDa and that of boIL-4 from 20 kDa to 13 kDa, which demonstrated that both cytokines contain N-linked oligosaccharides. Digestion with neuraminidase and O-glycosidase had no detectable effect on the apparent molecular masses, suggesting that BHV-1-expressed boIL-2 and boIL-4 are not, or only slightly, O-glycosylated. In vitro experiments demonstrated the biological activity of recombinant BHV-1-expressed boIL-2 and boIL-4 by their ability to maintain the proliferation of bovine 4325 T cells and activated bovine B cells, respectively. In conclusion, we show that boIL-2 and boIL-4 are secreted from recombinant BHV-1-infected cells as biologically active glycoproteins.

Animals↗
PubMed1996

Alcian blue. Now you see it, now you don't.

A brief outline of the history and chemistry of the copper pthalocyanin-based Alcian blue dyes highlights the adverse effects of commercial secrecy and entrepreneurial dishonesty on the use of these valuable histochemical and biochemical reagents in the biological sciences. The acquisition of detailed and validated chemical structures required the avoidable expenditure of much time that otherwise would have been spent on new research. The combination of this chemical knowledge with experiments on isolated polyanions, using critical electrolyte concentration (CEC) techniques, established a molecular recognition paradigm of Alcian blue usage in histochemistry. New reagents (Cuprolinic and Cupromeronic blues) were synthesised to investigate and support the hypothesis that Alcian blue did not intercalate with DNA. They were made with the important additional aim of using them in electron microscopy of polynucleotides (in the case of Cuprolinic blue) and non-nucleotide polyanions, such as sulphated proteoglycans in extracellular matrices (in the case of Cupromeronic blue). The cationic groups of Alcian blue are easily removed in very mild conditions, producing insoluble blue pigment in situ (ingrain dying). This reaction underlies its unique capability to stain in repeated cycles, thus greatly amplifying sensitivity of detection of substrates present in very small amounts in tissues and on electrophoretic strips etc.

Alcian Blue↗
PubMed1995

Comparison of secondary structures in water of chondroitin-4-sulfate and dermatan sulfate: implications in the formation of tertiary structures.

Chondroitin-4-sulfate (CS4) and dermatan sulfate (DS) were examined in D2O solution, with or without NaCl, by NMR at 300 MHz, to investigate the physicochemical consequences of epimerization of glucuronate (GlcUA in CS4) to iduronate (IdoUA in DS). Nuclear Overhauser effects (NOEs) and spin-lattice relaxation times following selective and nonselective inversion were measured at up to 70 degrees C. (1) NOEs confirmed 4C1 conformations of sugar rings in N-acetylgalactosamine and GlcUA, and 1C4 or 2S0 in IdoUA. Conflict between NMR data and periodate oxidation kinetics over IdoUA conformations is resolvable by postulating conversion of monodentate periodate-1C4 complexes to conformations in which periodate oxidation can procede. (2) Pairs of glycosidic protons in CS4 and DS showed strong NOEs, implying that stretches of 2-fold helix were present, with carboxylate and acetamido groups close to each other on the same side of tapelike molecules, extending previous work in dimethyl sulfoxide solution. CS4 and DS have large hydrophobic patches in this configuration, similar to those in keratan sulfate and hyaluronan. (3) Selective and nonselective inversion-recoveries implied similar segmental and backbone mobilities and hence flexibilities in CS4 and DS. This is discussed in terms of intrinsic flexibility of glycosidic conformations, modified by hydrogen-bonded arrays. (4) We postulate that hydrophobic and hydrogen bonding drives DS self-aggregation. Stronger self-aggregation of DS compared with CS4 is attributed to increased intermolecular hydrogen-bonding in DS, secondary to decreased intramolecular hydrogen-binding. This is partly because the axial OH groups in 1C4 IdoUA cannot hydrogen-bond to neighboring sugars as can the equatorial OH groups in GlcUA of CS4.

Animals↗
PubMed1995

Fourier-transform infrared spectroscopic analysis of rabbit lung surfactant: subfraction-associated phospholipid and protein profiles.

Surfactant obtained from bronchoalveolar lavage (BAL) can be separated into subfractions based on sedimentation characteristics. It has been suggested that the 10,000 x g, 60,000 x g and 100,000 x g subfractions isolated by this approach represent stages of surfactant extracellular processing. These three subfractions have been reported to differ in their morphology, composition and ability to lower surface tension. We wished to determine if infrared spectroscopy, which may be applied as a non-invasive technique could potentially prove useful for characterization and quantification of bronchoalveolar lavage (BAL) protein and phospholipid, and if this approach could detect differences in intermediate surfactant processing stages. Subfractions were collected from adult rabbit lungs by BAL and differential centrifugation and analyzed by Fourier transform infrared (FT-IR) spectroscopy. Biochemical assay of phospholipid and protein showed differences between subfractions that correlated well with the phospholipid/protein ratios obtained from FT-IR spectra (r = 0.939; r2 = 0.882). The subfraction sedimenting at 100,000 x g (P100) exhibited spectral shifts in the Amide I band, suggesting that the protein secondary structure was different compared to other fractions. Spectra obtained after separation of lipids and protein components showed an apparent disordering of protein secondary structure but little or no effect on the structure or mobility of phospholipids. These results support the idea that subfractions represent various processing stages of surfactant. In addition, they show that results from FT-IR analyses correlate significantly with traditional biochemical assay methods which may prove of clinical use.(ABSTRACT TRUNCATED AT 250 WORDS)

Amides↗
PubMed1995

MHC class I expression and transport in a calnexin-deficient cell line.

The human leukemic cell line, CEM, and an NK-resistant variant of CEM, called CEM-NKR, were analyzed for protein differences by two-dimensional gel electrophoresis. One protein was found to be completely absent in CEM-NKR. This protein has been identified as calnexin. CEM-NKR also completely lacks calnexin RNA. Calnexin is thought to act as a molecular chaperone by assisting in the assembly and/or retention of MHC class I and many other membrane and secreted proteins. The surface expression of class I molecules on CEM-NKR was compared with CEM by several Abs. There was no significant class I expression differences between CEM and CEM-NKR using w6/32 (a conformational and beta 2-microglobulin-dependent mAb), HC-10 (a conformational and beta 2-microglobulin-independent mAb), and an anti-class I antiserum that reacts with native and denatured class I. The transport rate of class I in both cell lines was examined by pulse-chase experiments, immunoprecipitating class I with w6/32 and anti-class I antiserum. The results show that class I molecules in the calnexin-deficient cell line and its parent cell line are transported at similar rates. These results indicate that calnexin is not absolutely required for the viability of CEM or the transport and surface expression of human MHC class I molecules.

Biological Transport↗
PubMed1995

Site-directed mutagenesis of varicella-zoster virus thymidylate synthase. Analysis of two highly conserved regions of the enzyme.

We have constructed a series of mutants to study the role of two structurally and functionally important regions of thymidylate synthase (TS) from varicella-zoster virus (VZV). The first centres on a conserved glycine residue in the beta-kink of beta-strand i, a partially buried region of the protein that is important for dimer interactions and the formation of the active site. We show that the glycine residue located in beta-strand i is not essential for enzyme activity and that beta-strand i can readily accommodate several amino acid substitutions and also an insertion. A covariant residue that accommodates these changes was also identified. The second region of interest was the solvent-exposed and highly mobile C-terminal residue which is an essential component of the active site in TS from Lactobacillus casei and Escherichia coli. We demonstrate that removal of the C-terminal residue from VZV TS does not completely inactivate the enzyme, implying that there are significant structural differences between the virus and bacterial enzymes. By combining site-directed mutagenesis and molecular modelling we have identified these differences and propose a model that explains the contrasting activities.

Base Sequence↗
PubMed1995

FT-IR spectroscopy of methylmercury-exposed mouse lung.

Infrared spectroscopy which has traditionally been utilized by chemists and physicists for characterization and identification of the structural properties of chemical compounds is now becoming more relevant as a biodiagnostic tool. Recent reports suggest that arthritis and Alzheimer's disease can be diagnosed by using this technique. Changes associated with these diseases diagnosable with this technique are generally overt. In this study we have used 'Fourier transform infrared spectroscopy' (FT-IR) to analyze subtle changes in composition and structure of lipids and proteins in lung tissue, bronchoalveolar lavage and purified lamellar body fraction of mice exposed to methylmercury. Infrared measurements were made in attenuated total reflection mode using the Split Pea (Harrick Scientific Corporation, USA). Mice were treated with 4 doses of methylmercuric chloride (15 mg/kg body weight/dose), and control animals received an equivalent volume of physiological saline. Comparison of the control and experimental spectra revealed alterations in the intensities and frequencies of vibrational modes of lipids following methylmercury exposure. Results indicate that FT-IR spectral analyses may be a valuable tool for detecting subtle variations in biological components associated with drug exposure to lungs and, in particular may be very useful for assessing changes in bronchoalveolar lavage.

Animals↗
PubMed1995

Heat treatment of leukemic cell lines can increase their sensitivity to NK lysis.

The effect of stress on target cell susceptibility to human natural killer cell-mediated lysis was examined. Targets were incubated at 37, 42, or 45 degrees C for 1 hr and then tested for NK sensitivity in chromium-release assays. The T cell target JURKAT displayed minor increases in susceptibility to NK lysis with 42 degrees C pretreatment (20-50% increases) and dramatic increases in lysability with 45 degrees C pretreatment (100-300% increase) compared to control. In contrast, lysis of the NK prototypic target K562 is not increased after 42 or 45 degrees C pretreatment. Kinetic studies indicated an optimal NK sensitivity enhancement time of 1 hr at 45 degrees C for JURKAT. Inhibition of target cell protein synthesis by emetine pretreatment does not produce an increase in susceptibility to NK lysis. JURKAT cells pretreated with sodium arsenite exhibited a comparable increase in NK sensitivity to the heat treatments. Cold target inhibition assays suggest that the increase in sensitivity after heat treatment is at a postbinding stage. This was exemplified by the increased sensitivity of JURKAT, but not K562, to lysis mediated by isolated rat NK granules. These results indicate that a heat-sensitive, de novo protein synthesis-independent defense mechanism against lysis may exist in some tumors, altering their susceptibility to lysis by NK cells.

Arsenites↗
PubMed1995

The effects of mechanical stimulation on the distribution of beta 1 integrin and expression of beta 1-integrin mRNA in TE-85 human osteosarcoma cells.

Mechanical stimulation of the skeleton alters the metabolism of bone cells, but the effects of mechanical strain on the cytoskeleton of osteoblasts are poorly understood. While changes in the distribution of the cytoskeleton in mechanically strained cells have been reported, little is known about the pathways by which these changes are transduced into cell functions. Human osteosarcoma (HOS) TE-85 cells were cultured in Dubelcco's modified Eagle's medium/F-12 and grown to confluency in Flexercell type I dishes in a humidified incubator with 5% CO2 and 95% air. Intermittent strain (3 cycles/min) was applied to the cells for periods of 15 and 30 min, 2, 4 and 24 h, and 3, 5, 7, 10, 14, 20 and 28 days. Unstrained cells were used as controls. The distribution of beta 1 integrin was studied immunocytochemically. Total RNA was isolated at every period of time and Northern blots were used to study the effects of strain on the levels of beta 1-integrin expression. The results indicated that mechanical strain increased the synthesis of beta 1 integrin. Northern blots showed that beta 1 mRNA expression was increased significantly (p < 0.005) at 30 min and 3 days of strain application. Strain also affected beta 1 distribution markedly in 24-h cultures. The response of HOS cells to mechanical strain demonstrates that the cytoskeleton of the osteoblast adapts to strain through the stimulation of specific cytoskeletal and receptor proteins. These results suggest a pathway through which mechanical strain is transmitted to the osteoblastic-like cells.

Analysis of Variance↗
PubMed1995

Ca(+2)-phosphatidylserine-dependent protein kinase C activity in fetal, neonatal and adult rabbit lung and isolated lamellar bodies.

Evidence indicates that Ca(+2)-phosphatidylserine-dependent protein kinase C (PKC) is involved in regulation of surfactant secretion. This study was done to examine PKC activity in lung as surfactant synthesis and secretion is initiated, and at birth and to compare these enzyme levels with those in the adult lung. NZW rabbits were used. Fetal and adult lungs were fractionated into subcellular compartments including a lamellar body fraction, which represents intracellular surfactant. The time course for microsomal enzyme activity was compared between 24th gestational day and adult rabbit lung. The reactivity appeared similar in both fractions. PKC specific activity displayed a prominent peak between the 27th and 30th gestational days in total homogenate and lamellar bodies. Specific activity was also high in nuclear, mitochondrial and microsomal fractions the day prior to birth. Adult levels were similar or higher. Total PKC activity was high during late gestation but declined sharply the day prior to birth. A marked increase was present on the first postnatal day. In contrast lamellar bodies displayed a peak in activity between the 27th and 30th gestational days followed by a decline to adult levels. Delipidation of lamellar body fraction indicated that the high enzyme activity in this fraction on the 27th gestational day was not artifactual. The changes observed in PKC in fetal, neonatal and adult lung indicate this enzyme activity changes in lung during the period of onset of surfactant synthesis and secretion during late gestation and may be associated with lamellar bodies, in 27th gestational day fetal lung.

Animals↗
PubMed1995

Schizophrenia: treatment outcomes research--editors' introduction.

Considerable research over the past few decades on the nature and treatment of schizophrenia has yielded important advances to improve the outcomes of this disorder. Recent action plans, including the "Decade of the Brain," the National Institute of Mental Health (NIMH) A National Plan for Schizophrenia Research, and NIMH's report, Caring for People With Severe Mental Disorders: A National Plan of Research to Improve Services, promise major new advances over the next several years. As research advances, it is critical to ensure that patients in everyday practice receive the most effective treatments being developed. This issue of the Schizophrenia Bulletin reviews the research on outcomes of treatments for schizophrenia and lays out an agenda for available research knowledge to be translated into practice and for future research to improve outcomes.

Combined Modality Therapy↗
PubMed1995

Psychological interventions for schizophrenia.

This review examines the impact of dynamic and supportive psychotherapies (both individual and group) and psychosocial skills training on clinical and social outcomes for individuals with schizophrenia. The relatively few controlled trials of individual or group psychotherapies for persons with schizophrenia exhibit serious methodological problems that limit their generalizability. Reality-oriented approaches appear to be superior to dynamic, insight-oriented psychotherapies, but further research is needed to identify and evaluate disorder-specific models that target specific deficits and disabilities in schizophrenia. Research on psychosocial skills training models shows that target skills can be trained and maintained over time. Further work is needed to determine the extent to which trained skills generalize from the original training setting to "real life" environments.

Behavior Therapy↗
PubMed1995

Assertive community treatment and case management for schizophrenia.

This review examines the impact of assertive community treatment (ACT) and case management models on the use of inpatient hospitalization and other community mental health services, costs, and other clinical and social outcomes. ACT programs have been found to reduce hospitalization and increase use of community mental health services at an equivalent or reduced cost. Greater fidelity to the ACT model produced better outcomes. The impact of case management models is less consistent, but intensive case management programs also have been found to reduce hospitalization. We discuss limitations in past research and recommend future directions.

Case Management↗
PubMed1995

Measuring the fetal kidney with ultrasonography.

OBJECTIVES: To establish a normal range of measurements for the external and internal dimensions of the fetal kidney and, if possible, to correlate these measurements with gestational age. SUBJECTS AND METHODS: The external and internal dimensions of the fetal kidney were measured in 810 women selected on the grounds of obstetric, fetal or technical risk factors from a consecutive series of 1136 women attending the ante-natal ultrasonography clinic of a district general hospital. Post-natal data were obtained from medical records on 1122 newborns. The maximum of pairs of renal measurements was used for analysis. Measurements were cross-sectional in 347 cases and longitudinal in 463. The total number of measurement episodes was 2294. RESULTS: External renal dimension and gestational age were closely related, enabling accurate growth centile charts to be constructed. The correlation between renal pelvic dimension and gestational age was weak. The maximum dimension of the renal pelvis at any gestational age in 92.7% of fetuses was < 5 mm. Using longitudinal measurements, 6.5% of cases with a renal pelvic dimension of < 5 mm at the first scan measured > or = 5 mm at a subsequent scan, but 53.3% with a dimension of > or = 5 mm at the first scan also measured > or = 5 mm at the subsequent scan. CONCLUSION: It is possible to assess the growth and size of the fetal kidney according to gestational age but this does not apply to the renal pelvis. A renal pelvic dimension of > 5 mm at any gestational age is unusual and dilatation beyond this level should prompt a detailed post-natal urological investigation.

Female↗