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Biomedical subjects

G Wilcox

Publications and source records attributed to G Wilcox.

At least 19 recordsLinked to original sources
PubMed2006

Urinary excretion of equol by postmenopausal women consuming soymilk fermented by probiotic bifidobacteria.

OBJECTIVE: To study the effects of consuming isoflavone aglycone-enriched soymilk fermented by bifidobacteria on urinary excretion of equol with respect to fermentation, daidzein dose, supplementation duration and background diet. DESIGN: Double-blind crossover pilot study comprising three 14-day supplementation periods separated by a washout. SETTING: Victoria University, Melbourne, Australia. SUBJECTS: Sixteen postmenopausal women. INTERVENTION: SUBJECTS randomized into two groups consuming either fermented (FS) or non-fermented soymilk (NFS), ingested three daily dosages of daidzein via soymilk and collected pooled urine specimens. Daidzein and equol were quantified using high-performance liquid chromatography. RESULTS: After 14-days supplementation six women (38%) excreted equol (>1 micromol equol/day), including four from the FS group, two of whom were classified as non-producers at day 4. Bifidobacteria ingestion, composition of daidzein and its glucosides, and carbohydrate intake appeared to influence equol formation among equol producers. CONCLUSIONS: Pilot-study group mean urinary equol excretion results provided insufficient evidence (P>0.05) that FS consumption instigates equol production in women predetermined as non-producers.

Bifidobacterium↗
PubMed2005

Body composition in young adults with inborn errors of protein metabolism--a pilot study.

The natural history of inborn errors of protein metabolism and the long-term effects of prescribed semisynthetic therapeutic diets are largely unknown. We assessed body composition, measuring body-fat mass and distribution, fat-free mass, total body protein, total body potassium, bone density and skeletal muscle mass, in young adults (age > 18 years; 6 female, 5 male) with inborn errors of protein metabolism maintained on long-term low-protein diets, compared with controls. Female patients were significantly shorter (159.4 cm vs 169.2 cm, p = 0.013) and had higher BMI (25.3 vs 22.0 kg/m2, p < 0.05), abdominal to gluteal circumference ratio (0.84 vs 0.73, p = 0.011), percentage body fat (42.3% vs 29.5%, p < 0.005) and ratio of central to peripheral body fat (1.15 vs 0.86, p < 0.05) than controls. Male patients had lower height-adjusted total body bone mineral content (0.9 vs 1.02 g/m2, p < 0.04) and skeletal muscle mass (31.1 vs 36.3 kg, p < 0.04) than controls. Compared with controls, patients'nitrogen index was significantly lower (0.91 vs 1.03, p < 0.01), consistent with lower total body protein. Potassium index was significantly higher (121.2% vs 110.4%, p < 0.03), consistent with higher body cell mass, or intracellular water. Documentation of body composition in larger patient series is important to elucidate whether these results reflect increased risks (hence opportunities for prevention) of bone disease, metabolic syndrome and cardiovascular disease in this population.

Absorptiometry, Photon↗
PubMed2001

Measurement of cardiac troponin I levels in the emergency department: predictive value for cardiac and all-cause mortality.

OBJECTIVE: To assess the predictive value of cardiac troponin I levels in cardiac and all-cause mortality in patients presenting to an emergency department. DESIGN: A prospective cohort study. SETTING: The emergency department of a major tertiary teaching hospital in metropolitan Melbourne over a six-week period in 1998. PATIENTS: All patients with requests for cardiac enzyme level measurement. MAIN OUTCOME MEASURES: Cardiac and all-cause mortality within 30 days of presentation. RESULTS: 424 patients (232 men, 192 women; age range, 16-93 years) were reviewed. The 30-day mortality rate was 7.3% (31/424); in patients with raised levels of both creatine kinase (CK)-MB isoenzyme and troponin I this rate was 27% (7/26; 95% CI, 13%-44%); and in those with troponin I levels above 2 microg/L, but normal CK-MB values, it was 24% (5/21; 95% CI, 5%-43%). The mortality rate in the group with normal results of cardiac markers was 4.3% (14/328; 95% CI, 2.1%-6.5%). Patients with minor increases in troponin I levels (minimal myocardial damage) showed an intermediate 30-day mortality rate (13%, 5/39; 95% CI, 2%-24%). Other predictors of 30-day mortality included age, presentation with shortness of breath, and electrocardiography (ECG) changes diagnostic of acute myocardial infarction or consistent with ischaemia. Cardiovascular causes were responsible for most of the deaths in patients with raised troponin I levels. Multivariate logistic regression analysis showed that raised levels of troponin (> 2.0 microg/L), but not of CK-MB, predict 30-day mortality rate. CONCLUSIONS: Compared with CK-MB, cardiac troponin I more accurately predicts 30-day mortality rates in patients presenting to the emergency department. Moreover, troponin I levels identify additional groups of patients at increased risk of death not so identified by measuring CK-MB values.

Adolescent↗
PubMed2000

Jembrana disease virus Tat can regulate human immunodeficiency virus (HIV) long terminal repeat-directed gene expression and can substitute for HIV Tat in viral replication.

Jembrana disease virus (JDV) is a bovine lentivirus genetically similar to bovine immunodeficiency virus; it causes an acute and sometimes fatal disease in infected animals. This virus carries a very potent Tat that can strongly activate not only its own long terminal repeat (LTR) but also the human immunodeficiency virus (HIV) LTR. In contrast, HIV Tat cannot reciprocally activate the JDV LTR (H. Chen, G. E. Wilcox, G. Kertayadnya, and C. Wood, J. Virol. 73:658-666, 1999). This indicates that in transactivation JDV Tat may utilize a mechanism similar to but not the same as that of the HIV Tat. To further study the similarity of JDV and HIV tat in transactivation, we first tested the responses of a series of HIV LTR mutants to the JDV Tat. Cross-transactivation of HIV LTR by JDV Tat was impaired by mutations that disrupted the HIV type 1 transactivation response element (TAR) RNA stem-loop structure. Our results demonstrated that JDV Tat, like HIV Tat, transactivated the HIV LTR at least partially in a TAR-dependent manner. However, the sequence in the loop region of TAR was not as critical for the function of JDV Tat as it was for HIV Tat. The competitive inhibition of Tat-induced transactivation by the truncated JDV or HIV Tat, which consisted only of the activation domain, suggested that similar cellular factors were involved in both JDV and HIV Tat-induced transactivation. Based on the one-round transfection assay with HIV tat mutant proviruses, the cotransfected JDV tat plasmid can functionally complement the HIV tat defect. To further characterize the effect of JDV Tat on HIV, a stable chimeric HIV carrying the JDV tat gene was generated. This chimeric HIV replicated in a T-cell line, C8166, and in peripheral blood mononuclear cells, which suggested that JDV Tat can functionally substitute for HIV Tat. Further characterization of this chimeric virus will help to elucidate how JDV Tat functions and to explain the differences between HIV and JDV Tat transactivation.

Animals↗
PubMed1999

Characterization of the Jembrana disease virus tat gene and the cis- and trans-regulatory elements in its long terminal repeats.

Jembrana disease virus (JDV) is a newly identified bovine lentivirus that is closely related to the bovine immunodeficiency virus (BIV). JDV contains a tat gene, encoded by two exons, which has potent transactivation activity. Cotransfection of the JDV tat expression plasmid with the JDV promoter chloramphenicol acetyltransferase (CAT) construct pJDV-U3R resulted in a substantial increase in the level of CAT mRNA transcribed from the JDV long terminal repeat (LTR) and a dramatic increase in the CAT protein level. Deletion analysis of the LTR sequences showed that sequences spanning nucleotides -68 to +53, including the TATA box and the predicted first stem-loop structure of the predicted Tat response element (TAR), were required for efficient transactivation. The results, derived from site-directed mutagenesis experiments, suggested that the base pairing in the stem of the first stem-loop structure in the TAR region was important for JDV Tat-mediated transactivation; in contrast, nucleotide substitutions in the loop region of JDV TAR had less effect. For the JDV LTR, upstream sequences, from nucleotide -196 and beyond, as well as the predicted secondary structures in the R region, may have a negative effect on basal JDV promoter activity. Deletion of these regions resulted in a four- to fivefold increase in basal expression. The JDV Tat is also a potent transactivator of other animal and primate lentivirus promoters. It transactivated BIV and human immunodeficiency virus type 1 (HIV-1) LTRs to levels similar to those with their homologous Tat proteins. In contrast, HIV-1 Tat has minimal effects on JDV LTR expression, whereas BIV Tat moderately transactivated the JDV LTR. Our study suggests that JDV may use a mechanism of transactivation similar but not identical to those of other animal and primate lentiviruses.

Amino Acid Sequence↗
PubMed1998

Patterns of high-grade prostatic intraepithelial neoplasia associated with clinically aggressive prostate cancer.

High-grade prostatic intraepithelial neoplasia (PIN) is the only widely accepted precursor lesion for prostatic adenocarcinoma (PCa). However, the spread of established PCa within prostatic ducts may be indistinguishable morphologically from high-grade PIN. By convention, all cytologically malignant cellular proliferations within prostatic ducts have been lumped into a PIN category, although there have been recent attempts by McNeal to develop reproducible criteria to separate high-grade PIN from the spread of established PCa within prostatic ducts--intraductal carcinoma (IDCa). Using McNeal's criteria for IDCa, we studied whole-mount sections from 252 patients with pT3NO PCa for the presence of IDCa and correlated the presence or absence of IDCa with Gleason score, total tumor volume, surgical margin status, seminal vesicle involvement, and disease progression. Patients with IDCa had higher Gleason score and total tumor volume and were more likely to show seminal vesicle involvement and disease progression than those patients without IDCa. In addition, IDCa was of independent prognostic significance. Total tumor volume and surgical margin status had no independent prognostic significance in this data set.

Adenocarcinoma↗
PubMed1998

Clinical review 92: Phytoestrogens.

We have reviewed the literature regarding the food sources, potency, population intakes, and known biological effects of phytoestrogens in humans using MEDLINE data base from the years 1975-1996. Over 600 articles pertinent to the metabolism of phytoestrogens, including female reproduction (in particular menstruation and menopause), cardiovascular disease, osteoporosis, and cancer were assessed including relevant case control or cohort studies, as well as randomized trials and review articles. Epidemiological studies regarding human data were included, as well as human cell line and animal studies when there were no relevant human data available. We conclude that phytoestrogens exhibit physiological effects in humans. Mild estrogenic changes occur in postmenopausal women. Benefits are seen regarding hypercholesterolaemia. Epidemiological, animal, and in vitro data encourage further assessment of the role of phytoestrogens in cancer prevention.

Cardiovascular Diseases↗
PubMed1997

Visualization of ventricular fibroelastoma with a video-assisted thoracoscope.

Left ventricular papillary fibroelastomas are associated with a high risk of cerebral embolization. Two-dimensional echocardiography and intraoperative transesophageal echocardiography are helpful in diagnosing tumors, planning a surgical approach, and achieving adequate excision. A video-assisted thoracoscope via the left atrium was used to visualize a left ventricular papillary fibroelastoma. Thoracoscopic visualization facilitated excision of a mass within the chordae tendineae between the anterolateral papillary muscle and the left ventricular wall. Video-assisted thoracoscopy greatly facilitates exposure/excision of deeper intracavitary left ventricular masses.

Endoscopy↗
PubMed1995

In vitro and in vivo evidence for a tachykinin NK1 receptor antagonist effect of vapreotide, an analgesic cyclic analog of somatostatin.

Vapreotide, a long-acting somatostatin analog, possesses an analgesic effect. The purpose of this work was to determine a tachykinergic involvement. Vapreotide reduced substance P-induced biting and scratching in mice. This inhibitory effect of substance P action was confirmed by experiments performed on the bronchial apparatus of guinea-pigs known to possess tachykinin NK1 and NK2 receptors. (i) Vapreotide reduced the substance P-induced plasmatic exudation. (ii) It inhibited selectively the tachykinin-dependent second contractile phase induced by electrical field stimulation of isolated bronchi. (iii) It shifted to the right the concentration-effect curve of substance P-induced contraction of isolated main bronchi. The peptide displaced [3H]substance P (IC50 = 3.3 +/- 1.8 x 10(-7) M) from guinea-pig bronchial tachykinin NK1 sites. The displacement of [125I]neurokinin A, a specific tachykinin NK2 receptor ligand, needed higher concentrations (IC50 = 4.5 +/- 0.6 x 10(-6) M). It is concluded that vapreotide possesses an antagonist activity on guinea-pig tachykinin NK1 receptors; the involvement in its analgesic action is discussed.

Acetylcholine↗
PubMed1995

Dietary flour supplementation decreases post-menopausal hot flushes: effect of soy and wheat.

Plants contain compounds with oestrogen-like action called phytoestrogens. Soy contains daidzin, a potent phytoestrogen, and wheat flour contains less potent enterolactones. We aimed to show in 58 postmenopausal women (age 54, range 30-70 years) with at least 14 hot flushes per week, that their daily diet supplemented with soy flour (n = 28) could reduce flushes compared with wheat flour (n = 30) over 12 weeks when randomised and double blind. Hot flushes significantly decreased in the soy and wheat flour groups (40% and 25% reduction, respectively < 0.001 for both) with a significant rapid response in the soy flour group in 6 weeks (P < 0.001) that continued. Menopausal symptom score decreased significantly in both groups (P < 0.05). Urinary daidzein excretion confirmed compliance. Vaginal cell maturation, plasma lipids and urinary calcium remained unchanged. Serum FSH decreased and urinary hydroxyproline increased in the wheat flour group.

Adult↗
PubMed1994

A method to perform direct transcutaneous intrathecal injection in rats.

This work describes a method for performing direct intrathecal (i.t.) injections in rats without introducing a spinal catheter. Its ease of use in awake animals yields rapid and reproducible results with no sign of motor impairment. The quality of each injection was ensured by the observation of an injection-induced tail-flick. A 10-microL injection of methylene blue was well localized yielding a very limited diffusion along the spinal cord. The method was validated by demonstrating that morphine (i.t.) had a marked antinociceptive effect and that naloxone (i.t.) blocked the effect of systemic (s.c.) morphine in mononeuropathic rat.

Administration, Cutaneous↗
PubMed1994

Determination of lignans and isoflavonoids in human female plasma following dietary supplementation.

Plasma levels of the lignans enterodiol and enterolactone, and also the isoflavonic phyto-oestrogens daidzein, equol and genistein, are reported for postmenopausal Australian women consuming a traditional diet supplemented with linseed, soya flour or clover sprouts. Analysis was performed by gas chromatography-mass spectrometry, after enzymatic hydrolysis and ion-exchange chromatography. Following linseed supplementation, combined levels of enterolactone and enterodiol reached 500 ng/ml, whereas after soya flour or clover sprouts the respective concentrations of equol, daidzein and genistein reached 43, 312 and 148 ng/ml. Not all subjects were able to produce equol from daidzein. The possible relationship and role of these weak dietary oestrogens as restraining factors in the development of hormone-dependent cancers in Asian populations is discussed.

4-Butyrolactone↗
PubMed1993

Modification of the C terminus of cecropin is essential for broad-spectrum antimicrobial activity.

Cecropin A is a naturally occurring peptide with bactericidal activity against gram-negative and gram-positive bacteria. Production of large quantities of bactericidal peptides that are similar in structure and activity to cecropin A has been achieved by combining recombinant DNA techniques and techniques and chemical modification. Expression of the bactericidal peptide in Escherichia coli was accomplished through the formation of a fusion protein. The 5' end of the L-ribulokinase gene was fused to a single copy of a synthetic gene encoding cecropin A. A methionine codon was engineered between the two genes, and a methionylglycine extension was introduced at the C terminus of cecropin A. Cyanogen bromide treatment of the fusion protein yielded cecropin A with a C-terminal homoserine. The recombinant cecropin A with a homoserine at the C terminus did not kill most gram-positive bacteria tested. However, recombinant cecropin A with a chemically modified C terminus has antimicrobial activity similar to that of cecropin produced by cecropia pupae.

Anti-Bacterial Agents↗
PubMed1992

Mutations in the araC gene of Salmonella typhimurium LT2 which affect both activator and auto-regulatory functions of the AraC protein.

The araC gene encodes a regulatory protein, AraC, that acts as both an activator and a repressor of transcription of the genes involved in the transport and catabolism of L-arabinose in Salmonella typhimurium LT2. Five araC mutants which have altered regulatory properties were characterized. All are point mutations which would result in amino acid substitutions near the C terminus of AraC. Each mutation results in altered activator and auto-regulatory AraC function in vivo. In vitro DNA-binding assays showed that three mutant AraC have measurable lowered affinity for ara controlling site DNA. The data are consistent with a model in which there is a DNA-binding domain in the C terminus of AraC which functions in both activation and repression.

Alleles↗
PubMed1992

Characterization of the Erwinia carotovora peh gene and its product polygalacturonase.

The peh gene, encoding polygalacturonase (Peh), was identified in Erwinia carotovora strain EC and cloned in Escherichia coli. Recombinant Peh (re-Peh) was purified from E. coli strain 706 containing peh on a recombinant plasmid. The activity of the re-Peh protein is optimal at pH 5.5. The N-terminal and internal amino acid (aa) sequences of re-Peh were determined and compared to the aa sequence deduced from the nucleotide (nt) sequence of the cloned peh. The re-Peh has no similarity, based on either the nt sequences or the deduced aa sequences, to pectate lyases from the same Er. carotovora strain or other organisms.

Amino Acid Sequence↗
PubMed1991

Cloning and characterization of the L-rhamnose regulon in Salmonella typhimurium LT2.

A Salmonella typhimurium LT2 cosmid library was constructed, and a 46-kb recombinant plasmid was isolated that could complement an Escherichia coli rha mutant. Subsequent subcloning generated a 13.6-kb ClaI restriction fragment that contained a functional regulatory element. By complementation analyses using different subclones, the approximate physical locations of rhaT, rhaC1, rhaC2, rhaB, rhaA, and rhaD were determined. The nucleotide sequence spanning the rhaB and rhaC2 genes was determined.

Amino Acid Sequence↗