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Biomedical subjects

J Green

Publications and source records attributed to J Green.

At least 199 records · Page 11Linked to original sources
PubMed1998

Altering the anaerobic transcription factor FNR confers a hemolytic phenotype on Escherichia coli K12.

The recent outbreaks of Escherichia coli O157-associated food poisoning have focused attention on the virulence determinants of E. coli. Here, it is reported that single base substitutions in the fnr gene encoding the oxygen-responsive transcription regulator FNR (fumarate and nitrate reduction regulator) are sufficient to confer a hemolytic phenotype on E. coli K12, the widely used laboratory strain. The mechanism involves enhancing the expression of a normally dormant hemolysin gene (hlyE) located in the E. coli chromosome. The mutations direct single amino acid substitutions in the activating regions (AR1 and AR3) of FNR that contact RNA polymerase. It is concluded that altering a resident transcription regulator, or acquisition of a competent heterologous regulator, could generate a pool of hemolytic, and therefore more virulent, strains of E. coli in nature.

Amino Acid Sequence↗
PubMed1998

An aspartic proteinase expressed in the equine placenta.

This manuscript describes the cloning of a novel aspartic proteinase expressed in the placenta of the horse (order Perrisodactyla). Evidence for similar genes in the cat (Carnivora) and ruminants (Artiodactyla), indicates that these molecules have been conserved within widely divergent species with distinct types of placentation. Since ePAG is produced by the outer cell layer (trophoblast) of the placenta, it can tentatively be grouped with the pregnancy-associated glycoproteins (PAG) of cattle, sheep, and pig. The high sequence identity that ePAG shares with pepsinogens as well as the PAG, indicates that ePAG may be the evolutionary bridge that links these two groups of aspartic proteinases.

Animals↗
PubMed1998

The role of environmental contamination with small round structured viruses in a hospital outbreak investigated by reverse-transcriptase polymerase chain reaction assay.

In May 1994 an outbreak of vomiting and diarrhoea occurred in a 28-bed long-stay ward for the mentally infirm. The predominant symptoms were vomiting, diarrhoea, malaise and abdominal pain lasting for approximately 12 h in most cases. The attack rate was 62% (13/21) for patients and 46% (16/35) for staff members. Infection control measures were implemented (containment of infectious individuals, hand hygiene among staff and environmental decontamination) and the ward was closed to admissions. Affected staff were excluded from contact with patients and their food until asymptomatic for 72 h. The outbreak lasted for 17 days. Faecal samples from nine symptomatic persons were negative for bacterial enteric pathogens, Giardia, Cryptosporidium and group A rotavirus. Electron microscopy of 12 faecal samples and one sample of vomitus revealed small round structured virus (SRSV) particles in one faecal sample. A further 30 faecal samples and seven vomitus samples were tested by reverse transcription polymerase chain reaction (RT-PCR) for SRSV of which 12 (40%) and 1 (14%) were positive respectively. Twenty-eight throat swabs from symptomatic and asymptomatic patients were collected, three (9.5%) of which were positive for SRSV by RT-PCR. Thirty-six environmental swabs were collected on the affected ward, and 11 (30%) were positive by RT-PCR. Positive swabs were from lockers, curtains and commodes and confined to the immediate environment of symptomatic patients. The distribution of contamination supports the rationale of cohorting sick patients.

Cross Infection↗
PubMed1998

Translation, adaptation, and validation of the SF-36 Health Survey for use in Japan.

Development of the Japanese SF-36 was completed in two phases: Phase 1: Japanese version 1.1 was produced according to International Quality of Life Assessment (IQOLA) project guidelines, but some results of psychometric tests were unexpected. First, scores varied little across physical-functioning items. Second, using factor analysis, we could not clearly distinguish the scales designed to measure the "physical" component of quality of life from those designed to measure the "mental" component. Phase 2: Focus-group discussions revealed that limited had often been interpreted as limited by a doctor. Therefore, is difficult to do was used instead (version 1.2). Results of two surveys indicated that version 1.2 yields scores that are reliable by internal consistency and test-retest standards and yields two principal components. In Japan, however, the pattern of correlations between some scales and the principal components differs from that in the United States. Iterative use of qualitative and quantitative methods was very important in developing the Japanese SF-36.

Cross-Cultural Comparison↗
PubMed1998

Basal cell carcinoma development is associated with induction of the expression of the transcription factor Gli-1.

Recent work has established that activation of Hedgehog/patched signalling plays a key role in the development of basal cell carcinomas (BCCs). In Drosophila the effects of hedgehog signalling are mediated by the transcription factor Cubitus interruptus, which is homologous to the mammalian Gli family of transcription factors. In order to investigate the downstream consequences of patched gene inactivation in BCCs, we have investigated the expression of Gli-1 and Gli-3 in normal skin and BCCs by reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization. Gli-3 was found to be expressed in both normal skin and BCCs by both RT-PCR and in situ hybridization using a Gli-3-specific probe. Using a sensitive RT-PCR assay we were unable to detect Gli-1 transcripts in normal skin. Gli-1 was expressed in 13 of 14 BCCs examined, and in situ hybridization confirmed that the transcripts were localized to the epithelial component of the tumours. Our results demonstrate that inactivation of the patched gene BCCs is associated with the accumulation of Gli-1 transcripts. These findings suggest that the Gli-1 transcription factor plays a key role in BCC development.

Basal Cell Carcinoma↗
PubMed1998

Downregulation of Escherichia coli yfiD expression by FNR occupying a site at -93.5 involves the AR1-containing face of FNR.

The promoter of the FNR-activated yfiD gene of Escherichia coli has an unusual architecture because it contains two FNR sites, an arrangement usually associated with FNR-mediated repression. Investigation of yfiD promoter derivatives with altered FNR sites revealed that occupation of the far upstream FNR site (FNR II) downregulated expression, despite the presence of a FNR dimer activating expression from the promoter proximal site (FNR I). Transcript mapping by primer extension, and mutagenesis of potential -10 elements, indicated that yfiD expression is driven from a single FNR-dependent promoter with FNR sites at -40.5 (FNR I) and -93.5 (FNR II). However, yfiD mRNA is processed in stationary-phase cultures independently of rne, rpoS, ihfA and fis to yield transcripts lacking 12 and 21 bases from their respective 5' ends. Single amino acid substitutions (G74-->C, F92-->S, A95-->P, R184-->P, P188-->A or L193-->P) in the surface of FNR that contains activating region 1 (AR1 contacts the alpha-subunit of RNA polymerase to promote transcription activation) reduced the inhibitory effect of FNR at FNR II, indicating that this region of the protein may have a role in repression as well as activation. The FNR variant F92-->S was notable because, although it activated transcription of yfiD (two FNR sites), it was unable to activate transcription from model Class I and II promoters, which contain only a single FNR site.

Amino Acid Substitution↗
PubMed1998

Shortcomings in psychosocial history taking in a paediatric emergency department.

OBJECTIVE: To assess the quality of documentation of the psychosocial history taken from parents who repeatedly bring their infants and young children to an emergency department. METHODOLOGY: We prepared a list of 26 psychosocial items, indicated by the literature to be important elements of a history taken in this setting. We then reviewed subjects' casenotes, and compared each history to this ideal list. PARTICIPANTS/SETTING: Case note review of 104 children under 2 years who had presented to a paediatric emergency department at least five times in 1 year. RESULTS: Documentation of psychosocial history for these subjects was very poor, with a mean of only 5 of the 26 possible psychosocial items mentioned per set of casenotes. The majority of records lacked important information, including basic demographic data. CONCLUSIONS: We canvass possible reasons for poor psychosocial history taking, and argue for changes in medical education, the development of techniques to efficiently identify at risk children and families, and improved resources for referral.

Australia↗
PubMed1998

A nested reverse transcriptase PCR assay for detection of small round-structured viruses in environmentally contaminated molluscan shellfish.

We describe the evaluation of a nested reverse transcriptase PCR (RT-PCR) procedure for the detection of small round-structured viruses (SRSVs) in molluscan shellfish and the application of this assay for the detection of SRSVs in commercially produced shellfish and in shellfish implicated in outbreaks of gastroenteritis. The range of virus strains detected and the sensitivity of detection were evaluated by using a representative panel of 21 well-characterized SRSV strains. The nested RT-PCR detected 15 of 21 SRSVs, demonstrating that the assay detects a broad range of SRSVs including strains from both genogroup I and genogroup II. Seeding experiments showed the nested RT-PCR assay to be 10 to 1,000 times more sensitive than the single-round RT-PCR assay for the detection of SRSV in shellfish. SRSV-contaminated samples were identified by nested RT-PCR for shellfish grown in polluted harvesting areas and for shellfish associated with outbreaks of gastroenteritis which were negative by a previously described single-round RT-PCR. The assay was shown to be effective for investigation of virus elimination during commercial shellfish processing procedures such as depuration and relaying and has potential applications for monitoring at-risk shellfish harvesting areas, for investigation of SRSV contamination in shellfish from producers linked to gastroenteritis outbreaks, and for the direct detection of virus in shellfish implicated in outbreaks.

Polymerase Chain Reaction↗
PubMed1998

Children's views of accident risks and prevention: a qualitative study.

OBJECTIVES: To examine children's accounts of injury risks and opportunities for prevention. SETTING: Schools, youth clubs, and a holiday activity scheme in the south east of England. METHODS: Sixteen focus groups were held with 7-11 year old children. Transcripts of the discussions were analysed using qualitative methods. RESULTS: Children were knowledgeable about injury risks and how to reduce them. They also saw injury prevention as primarily their own responsibility. However, they were also sophisticated in their criticisms of generalised prevention advice, and evaluated safety messages in the light of local environmental and social knowledge. Personal experience was more often reported as a reason for risk reduction than formal prevention advice. Risks for injury were not isolated from other risks faced. CONCLUSIONS: Effective educational interventions aimed at changing children's risk behaviour should build more on children's own competence and knowledge of their local environment, and stress the need to manage risks rather than avoid dangers.

Accident Prevention↗
PubMed1998

Inflammatory cytokines (IL-1alpha, TNF-alpha) and LPS modulate the Ca2+ signaling pathway in osteoblasts.

Locally derived growth factors and cytokines in bone play a crucial role in the regulation of bone remodeling, i.e., bone formation and bone resorption processes. We studied the effect of interleukin (IL)-1alpha, tumor necrosis factor (TNF)-alpha, and Escherichia coli lipopolysaccharide (LPS) on the hormone-activated Ca2+ message system in the osteoblastic cell line UMR-106 and in osteoblastic cultures derived from neonatal rat calvariae. In both cell preparations, IL-1alpha, TNF-alpha, and LPS did not alter basal intracellular Ca2+ concentration ([Ca2+]i) but attenuated Ca2+ transients evoked by parathyroid hormone (PTH) and PGE2 in a dose (1-100 ng/ml)- and time (8-24 h)-dependent fashion. The cytokines modulated hormonally induced Ca2+ influx (estimated by using Mn2+ as a surrogate for Ca2+) as well as Ca2+ mobilization from intracellular stores. The latter was linked to suppressed production of hormonally induced inositol 1,4,5-trisphosphate. The effect of cytokines on [Ca2+]i was abolished by the tyrosine kinase inhibitor herbimycin A (50 ng/ml). The cytokine's effect was, however, independent of nitric oxide (NO) production, since NO donors (sodium nitroprusside) as well as permeable cGMP analogs augment, rather than attenuate, hormonally induced Ca2+ transients in osteoblasts. Given the stimulatory role of cytokines on NO production in osteoblasts, the disparate effects of cytokines and NO on the Ca2+ signaling pathway may serve an autocrine/paracrine mechanism for modulating the effect of calciotropic hormones on bone metabolism.

Animals↗
PubMed1998

Cortisol infusion depresses the ratio of bioactive to immunoreactive ACTH in adrenalectomized sheep fetuses.

We examined the effects of exogenous cortisol on plasma immunoreactive adrenocorticotropic hormone (iACTH), bioactive ACTH (bACTH), and ACTH-(1-39) in nine adrenalectomized fetuses at 126-130 and 136-140 days of gestation. Fetuses received 4 h of cortisol (2 micrograms.kg-1.min-1) or saline infusions on consecutive days. Blood was obtained before and at intervals during infusions. Arterial blood gases and hematocrits were normal and did not change with age. Plasma cortisol did not change during saline infusions but increased significantly (range 30-70 ng/ml) during cortisol infusions. Basal plasma iACTH, bACTH, ACTH-(1-39), and bACTH-to-iACTH and ACTH-(1-39)-to-iACTH ratios were significantly higher in the older fetuses. Cortisol infusions decreased plasma iACTH, bACTH, and ACTH-(1-39) in both groups, and the suppression as a percent of the baseline was similar. The bACTH-to-iACTH ratio declined to the same level at 126-130 (0.201 +/- 0.040 to 0.051 +/- 0.002) and 136-140 (0.389 +/- 0.088 to 0.046 +/- 0.002) days of gestation. These data suggest that physiological concentrations of cortisol selectively inhibit bACTH secretion, and the ACTH response to cortisol inhibition is not different between 126 and 140 days of gestation in adrenalectomized sheep fetuses.

Adrenal Glands↗
PubMed1998

Minimal-change nephropathy and malignant thymoma.

A 69-year-old woman presented with persistent dyspnea and continuous coughing and mediastinal mass. The mass was found to be a malignant thymoma and was resected incompletely. A full-blown nephrotic syndrome appeared 1 year after removal of the thymoma. Renal biopsy revealed minimal-change glomerulonephritis. There was no evidence of other autoimmune diseases or causes of the minimal-change glomerulonephritis.

Aged↗
PubMed1998

Acute oliguric renal failure associated with unilateral renal embolism: a successful treatment with iloprost.

A 66-year-old woman presented with acute-onset rapid atrial fibrillation and right upper quadrant pain which had appeared 24 h prior to admission. The patient also manifested acute oliguric renal failure (serum creatinine 6.9 mg/dl). Selective renal angiography revealed total occlusion of the right renal artery with normal visualization of the left kidney vasculature. The patient was treated with intra-arterial urokinase and intravenous heparin, with no response. Intravenous administration of the prostacyclin analogue, iloprost, resulted in rapid resolution (within hours) of the oliguric acute renal failure, in spite of the continuing presence of a nonfunctioning right kidney. We conclude that the etiology of the acute renal insult in this patient is probably related to unilateral renal arterial embolization accompanied by arterial spasm of the unaffected kidney. The contralateral vasospasm can be reversed by iloprost, which then leads to a rapid recovery from acute renal failure. We are unaware of prior reports documenting the beneficial effect of iloprost in a clinical setting as described here.

Acute Kidney Injury↗