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Biomedical subjects

R N Roy

Publications and source records attributed to R N Roy.

At least 19 recordsLinked to original sources
PubMed2005

Dibutyl phthalate, the bioactive compound produced by Streptomyces albidoflavus 321.2.

It was found that the bioactive compound, dibutyl phthalate, was produced by a new soil isolate Streptomyces albidoflavus 321.2. Once this active compound was recovered by ethyl acetate from the fermented broth, being possible to isolate 13.4 mg/l, it was purified by paper, silica gel column, thin layer and gas chromatography. Structure was determined by analysing UV, IR and GC-MS spectra. During analysis, such active compound showed strong activity against gram-positive and gram-negative bacteria, as well as unicellular and filamentous fungi. The antimicrobial activity of the compound was reversed by the amino acid proline. No acute toxicity was observed.

Anti-Bacterial Agents↗
PubMed2005

Who's got what? A benchmarking exercise for tertiary neonatal units.

OBJECTIVES: To determine the current facilities available in level-3 neonatal units (NNU) in Australia and New Zealand to assist with establishment of standards for new NNU design. BACKGROUND: Many current NNU in Australia and New Zealand are planning new or redesigning existing facilities. There are no adequate local standards for NNU design available which reflect changing neonatal practices. METHODS: All level-3 neonatal units belonging to the Australia and New Zealand Neonatal Network (ANZNN) were invited to respond to a survey on NNU facilities. Questions were based around obtaining information on whether the NNU were planning to build or redesign the space and clinical facilities available in their existing facilities and what support and family spaces were provided. RESULTS: Twenty-six (six in New Zealand and 20 in Australia) of the 29 tertiary NNU in the ANZNN responded the survey. The oldest facility was built in 1960, with the most recent NNU being commissioned in 2003. Of the 26 responders, 18 indicated that they were planning to rebuild or renovate, with 13 anticipating completion within 6 years. The median floor area for existing level-3 cots was 11.1 m(2) (range 5.5-18.0 m(2)) and 5.8 m(2) (range 2.3-15.6 m(2)) for level-2 cots, respectively. Most units responded that storage space was insufficient (median 1.5 m(2) per cot, range 0.4-3.3 m(2) per cot). Most units had facilities for parents including a family lounge and parent overnight rooms, although 16 units indicated that they needed more overnight rooming in facilities. Noise levels in level-3 areas were described as being 'generally' or 'mostly noisy' in 14 of 25 responses, but noise levels in level-2 areas were less in the majority of responses. Privacy was cited as an issue for 80% of responding NNU with comments directed at either the layout or space constraints interfering with confidentiality or interactions with families. CONCLUSIONS: The majority of NNU have inadequate space and environmental control. The lack of space particularly impacts on infection control aspects, parental privacy and participation and staff satisfaction. Level-2 areas, where parent participation in the care of infants is often greater, should receive as much attention as higher technology level-3 areas. Furthermore, work should be undertaken to develop appropriate local recommendations for NNU design which are acknowledged by local government agencies and professional bodies and take into account the changes in neonatal care practices, integration of family in the care of infants and the needs of the staff.

Australia↗
PubMed2000

Effect of tamoxifen treatment on the endometrial expression of human insulin-like growth factors and their receptor mRNAs.

The effect of tamoxifen (Tam) treatment on the endometrial expression of IGF-I and II/IGF-IR and IIR mRNAs was assessed by measuring the levels of expression of these mRNAs in the endometrial samples of Tam-treated postmenopausal breast cancer patients by RT-PCR assays. The levels of these mRNAs were compared with those in normal endometrium and in Type I and Type II endometrial carcinomas (EC). The promoter-specific transcript profiles of IGF-I and II were also elucidated. The levels of IGF/IGF-R mRNAs in the endometrium from Tam-treated patients were found to be comparable with the high levels of these mRNAs observed in the proliferative and early secretory phase endometrium and in the samples of Type I EC. These results indicate that Tam acts as an estrogen agonist in inducing the endometrial expression of these genes. Tam stimulated transcription from the multiple promoters of IGF-I and II, with the exception of IGF-II P2 promoter, in which case the transcription across exon 4 appeared to be inhibited. The profiles of IGF-I and II transcripts of endometrium from Tam-treated patients were similar to Type I EC but differed considerably from those of Type II EC. These results suggest that the Tam-associated ECs are likely to be similar to type I EC and will therefore have a more favorable prognosis.

Antineoplastic Agents, Hormonal↗
PubMed2000

Loss of IGF-II imprinting in endometrial tumors: overexpression in carcinosarcoma.

The genomic imprinting of the maternal allele defines the monoallelic expression of the IGF-II gene in most human tissues. The loss of imprinting (LOI) leading to biallelic overexpression of IGF-II has been reported in several human malignancies, including uterine leiomyosarcoma. To ascertain if LOI occurs in endometrial malignancies, the allelic expression of the IGF-II gene was examined in samples of normal human endometrium (n=22) and endometrial tumors (n=12) by assessing the ApaI polymorphism in cDNA segments amplified by RT-PCR. The biallelic overexpression of IGF-II mRNA, involving activation of all four (P1-P4) promoters, was detected in one normal endometrium and in one endometrial carcinosarcoma. Low level biallelic expression of IGF-II was also detected in two samples of hormone-unresponsive/Type II endometrial carcinomas. The level of IGF-I mRNA in these four samples was low. The IGF-IR mRNA was overexpressed in all endometrial cancers including the carcinosarcoma sample, but not in normal endometrium. These data suggest that LOI associated with overexpression of IGF-II and concomitant overexpression of IGF-IR may play a role in the rare carcinosarcoma of the endometrium.

Carcinosarcoma↗
PubMed2000

Transcriptional induction of the conserved alternative sigma factor RpoS in Escherichia coli is dependent on BarA, a probable two-component regulator.

The stationary phase expression of many conserved, adaptive bacterial proteins is dependent on RpoS, a second vegetative sigma factor. The regulation of RpoS itself, however, is complex and not fully understood, particularly at the level of transcription. In this report, we show that the observed hydrogen peroxide sensitivity of a mutant defective in expression of barA, a bacterial virulence factor, can be explained by a reduction in catalase activity, an RpoS-controlled function. Levels of katE mRNA, encoding the major catalase of Escherichia coli, were much lower in the barA mutant, suggesting that BarA is required for the expression of this RpoS-regulated gene. Expression of another RpoS-regulated gene, osmY, was also found to be severely reduced in the barA mutant. Employing Western analyses with anti-RpoS antisera and Northern analyses using probes specific for rpoS, we found that BarA is required for the exponential phase induction of RpoS itself. Operon lacZ fusion expression studies and Northern analyses indicate that BarA itself is maximally expressed in early exponential phase cultures immediately preceding the transcriptional induction of RpoS. Results of primer extension studies indicate that exponential phase expression from the rpoSp1 promoter is reduced by more than 85% in a barA mutant but could be efficiently complemented by a plasmid-borne copy of barA in trans. These results suggest that regulatory signals that are operant in exponentially growing cultures play an important role in effecting stationary phase gene expression.

Bacterial Proteins↗
PubMed2000

Development and evaluation of a monoclonal antibody based competitive enzyme-linked immunosorbent assay for the detection of rinderpest virus antibodies.

A competitive enzyme-linked immunosorbent assay has been standardised for the detection of antibodies to rinderpest virus in sera from cattle, sheep and goats. The test uses a neutralising monoclonal antibody (MAb) directed against the haemagglutinin protein of rinderpest virus. The test is specific for rinderpest, as it failed to detect antibodies to peste des petits ruminants virus in convalescent goat sera. A 45% inhibition of the binding of the MAb to the antigen was used as the cut-off point for deciding the rinderpest status of the test samples. The specificity and sensitivity of the test and the stability of the test reagents were determined and compared to the results obtained using a commercial kit with approximately 1,200 serum samples from cattle, sheep and goats in India. The current test compared very well with the commercial kit. The test is expected to be extremely useful for sero-monitoring and sero-surveillance of rinderpest in countries which are actively pursuing a rinderpest eradication programme.

Animals↗
PubMed1999

Discordant expression of insulin-like growth factors and their receptor messenger ribonucleic acids in endometrial carcinomas relative to normal endometrium.

The inappropriate expressions of insulin-like growth factors (IGF-I and II) and IGF-I receptor (IGF-IR) are implicated in the malignant growth of many cancers. To determine changes, if any, in the levels of expression of IGFs and IGF receptor genes in neoplastic endometrium, relative to normal endometrium, the mRNA levels of IGF-I and II and of IGF-IR and IIR were measured in samples of endometrial carcinomas (EC) and normal endometrium, through all phases of the menstrual cycle, by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) assays. In normal endometrium, the mRNA levels of IGF-I were elevated in the proliferative and early secretory phases. The IGF-II mRNAs were relatively high in the proliferative phase, but unaltered through early and late secretory phases. Significantly elevated levels of IGF-II transcripts were observed during the menstrual phase, suggesting a possible role of IGF-II in endometrial regeneration. A positive correlation between the levels of IGF-I and IGF-IR mRNAs, apparent in the samples of normal endometrium, was not observed in endometrial carcinomas. The IGF-IR and IIR mRNA levels were elevated in endometrial carcinoma samples. On the other hand, the IGF-I and II mRNA levels were conspicuously low in many carcinoma samples, which were not associated with hyperplasia (type II EC), but relatively elevated in two other carcinoma samples, associated with adenomatous hyperplasia (type I EC). These results albeit with few samples suggest the possibility that the overexpressed receptor, IGF-IR, could be activated differently in two types of endometrial carcinomas, namely ligand-dependently in type I ECs and ligand-independently in type II ECs.

DNA, Complementary↗
PubMed1997

Endometrial transcripts of human insulin-like growth factors arise by differential promoter usage.

By the application of RT-PCR, we have demonstrated that in the human endometrium mRNAs for insulin-like growth factors, IGF-I and II, and their receptors are expressed not only in the intact endometrium, but also in the freshly isolated stromal and epithelial cells. The expression of multiple transcript forms of the IGF-I and II at various phases of the menstrual cycle, occurs by differential use of all four IGF-I transcriptional start sites, and two of the four known promoter sites of the IGF-II gene. The complete spectrum of transcripts is displayed by the proliferative phase and the menstrual phase endometrium. During the secretory phase, the exon 1 upstream start site of the IGF-I gene and the P2 promoter of the IGF-II gene are not used. Irrespective of the phase of the menstrual cycle, the stromal cells always display the same transcriptional patterns of both growth factor genes as those of the intact endometrium. In contrast, the epithelial cells do not express IGF-I transcript originating from the exon 2 upstream initiation site. These results indicate that the expressions of the IGF-I and II genes in the intact endometrium and stromal and epithelial cells are modulated at the transcriptional level during the menstrual cycle by differential usage of promoters and start sites.

Endometrium↗
PubMed1997

Minimal haemolysis in blood co-infused with amino acid and dextrose solutions in vitro.

OBJECTIVE: To examine the haemolytic effects of amino acid and dextrose solutions on co-infused packed red blood cells. METHODOLOGY: An in vitro study of packed cells co-infused at various rates with dextrose 5%, 10%, 15% and intravenous amino acid solution (Vamin; Kabi-Pharmacia, Baxter Healthcare Pty Ltd) in dextrose 5%, 10% and 15%. The degree of haemolysis was measured as free oxyhaemoglobin by spectrophotometer. Co-infused 0.9% saline and water were used as 0% and 100% haemolysis controls. RESULTS: Only minimal haemolysis was observed with the solutions tested. The greatest observed amount of haemolysis was 0.14%. CONCLUSIONS: Co-infusion of packed red blood cells with dextrose and amino acid solutions at the concentrations and infusion rates commonly used in neonatal care, does not cause clinically important haemolysis.

Amino Acids↗
PubMed1997

Control of temperature during newborn transport: an old problem with new difficulties.

OBJECTIVE: To explore any changes in temperature control during neonatal emergency inter-hospital transport between 1977 and 1996. METHODS: Records were reviewed of all infants undergoing emergency transfer by the statewide Victorian Newborn Emergency Transport Service (NETS). Per axillary temperatures were recorded prospectively on arrival of transport team and at conclusion of transfer for all infants. RESULTS: The rate of hypothermia (< 36.0 degrees C) when NETS reached the infant has decreased overall (22% in 1977-79 to 7% in 1995-96) and for all weight groups; although in 1995-96 hypothermia was present in 36% of infants less than 1000 g when NETS arrived. The rate of hypothermia (< 36.0 degrees C) at the end of the transfer has remained at 3% overall for many years. The rate of hyperthermia at both times has increased significantly overall (12% in 1977-79 to 24% in 1995-96 on NETS arrival, 4%-19%, respectively at end of transfer) and for all weight groups except infants less than 1000 g. The range of abnormal temperatures has not substantially changed over time. CONCLUSION: There has been significant improvement in avoidance of hypothermia and cold stress amongst infants requiring emergency neonatal transport from 1977 to 1996. However, in order to improve the number of infants transferred who achieve a temperature in the normal range the need to avoid hyperthermia is highlighted. Infants who require incubator care for optimal medical management require continual monitoring of temperature and review of environmental conditions to optimise the conditions both prior to and during transport.

Fever↗
PubMed1995

Genomic sequence, structural organization and evolutionary conservation of the 13.2-kDa subunit of rat NADH:ubiquinone oxidoreductase.

The 13.2-kDa subunit of NADH:ubiquinone oxidoreductase has been shown to be an integral part of the bovine iron-sulfur (IP) part of the protein. This subunit has been shown to interact with at least two other protein subunits of the IP fragment. The amino acid (aa) sequence of this subunit, determined from an acid extract of rat heart was used to generate an oligodeoxyribonucleotide probe which allowed isolation of a cDNA coding for the rat homologue of 13.2-kDa IP. The cDNA was used as a probe of a rat genomic DNA library and two clones were isolated, one of which contained the entire coding region for 13.2-kDa IP. Southern analysis indicates that the IP13 sequence exists as a single copy gene. The sequence of the genomic clone contains one intron and promoter elements including a TATAAA region. The 5' flank region has several potential regulatory sites, most notably regions similar to the nuclear respiratory factor 1 (NRF-1) motif, found in other genes which code for mitochondrial proteins [Evans and Scarpulla, Genes Dev. 4 (1990) 1023-1034]. The core domain of the deduced rat aa sequence has a high degree of identity with the mouse and cow homologues of this protein. The high degree of conservation of this protein indicates that the protein is essential for the function of complex I.

Amino Acid Sequence↗
PubMed1995

Gene expression of A- and B-type natriuretic peptides in response to acute ethanol ingestion.

Given that ethanol ingestion is associated with a disruption of water and electrolyte balance in addition to being a significant risk factor for cardiovascular disease, we have investigated the gene expression of ANP and BNP in response to acute doses of ethanol. Wistar rats were administered either a 5 g/kg dose of ethanol or an equivalent volume of water, and atrial and ventricular tissue samples were removed at 30, 60, and 120 min for analyses. Although no differences in ANP mRNA were observed between ethanol and water-treated rats during the time course, BNP mRNA levels in ethanol-treated rats were 43% of those present in water-treated animals in atrial tissue at 120 min. In ventricular tissue, BNP mRNA levels were reduced similarly to 38% of control. These results suggest a possible differential regulation of A- and B-type natriuretic peptides under the influence of ethanol ingestion.

Alcoholic Intoxication↗
PubMed1993

Chronic ethanol ingestion modifies the renin-aldosterone axis independent of alterations in the regulation of atrial natriuretic peptide.

Using an animal model, we have investigated the effects of chronic ethanol ingestion on the regulation of atrial natriuretic peptide (ANP) synthesis and release. Male Sprague-Dawley rats were maintained for 6 weeks on a liquid diet of ethanol (up to 20% v/v) as part of a 2% solution of calf milk replacer. Weight-matched controls received an equal volume of ethanol-free solution, and normal animals drank ad libitum. All animals received rat chow throughout the experiment. This model produced physiologically relevant levels of blood ethanol, as concentrations at the time of sacrifice were 171.98 +/- 39.26 mg/dl. Plasma renin activity was significantly elevated in response to ethanol treatment, whereas circulating aldosterone concentration was reduced. No alterations in the plasma or atrial tissue levels of ANP were evident, although we did observe a significant increase in the ventricular tissue levels of ANP from 45.1 to 71.8 ng/g as a consequence of ethanol treatment. Levels of both atrial and ventricular ANP mRNA were not different between alcohol-treated and liquid-restricted control animals, although both groups showed significant increases in the amount of transcript in comparison with rats drinking ad libitum. No significant increases in either arterial blood pressure or heart/body weight ratio were observed for ethanol-treated rats. These results suggest that modifications in the renin-aldosterone axis can occur independently of alterations in the regulation of ANP under the influence of chronic ethanol ingestion.

Alcoholism↗
PubMed1992

Expression of natriuretic peptide genes in cardiac tissues of hypertensive rats.

A quantitative assay using a reverse transcriptase-linked polymerase chain reaction has been developed for measuring the levels of rANP and iso-rANP mRNA. A linear correlation between total RNA template and amplified cDNA was obtained for the amplification of cDNA from both iso-rANP and rANP mRNAs even when both cDNAs were amplified in the same assay. Application of the assay showed that in contrast to rANP levels of iso-rANP transcript in hypertensive rats remained approximately the same in atrium but were increased 10-fold in ventricle compared to normal rats. Given the relative size of the ventricle the increase of iso-rANP in this tissue in SHR may be a major response to the hypertensive state.

Animals↗
PubMed1992

Crohn's disease & aflatoxins.

An investigation to examine the relationship between Crohn's disease and aflatoxins, a group of structurally related toxic and carcinogenic metabolites, was carried out on 24 patients. Extracts of serum and urine from the patients were assayed qualitatively by thin layer chromatography and the Aflatest method, and quantitatively by fluorimetry. There was evidence that some patients suffering from Crohn's Disease, together with some having coeliac disease and ulcerative colitis, did have varying amounts of aflatoxins in their serum and urine. The presence of aflatoxins may have been due to exposure to food containing these toxins or inability of the patient to excrete aflatoxins on account of some gastro-intestinal derangement. Only long-term investigation would establish the link between dietary history and the presence of aflatoxins in these patients.

Aflatoxins↗