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R N Roy

Publications and source records attributed to R N Roy.

At least 37 records · Page 2Linked to original sources
PubMed1990

Organization of the gene for iso-rANP, a rat B-type natriuretic peptide.

Using the polymerase chain reaction and oligonucleotide primers constructed from knowledge of the cDNA sequence we have sequenced the gene for iso-rANP, a peptide of the B-type of atrial natriuretic peptides. The overall organization of the rat iso-ANP gene is the same as that of ANP and BNP consisting of three exons and two introns at relatively similar positions. Iso-rANP and it's gene are more closely related to BNPs than ANP and yet there are significant differences at both the protein and DNA levels. Our results suggest that iso-rANP and BNP are distinct members of the same sub-family (B-type natriuretic peptides) within the family of natriuretic peptide genes.

Amino Acid Sequence↗
PubMed1990

Methods of delivery and resuscitation of very-low-birthweight infants in Victoria: 1982-1985.

This article describes the patterns of delivery and resuscitation for very-low-birthweight infants who were born in Victoria from 1982 to 1985. Caesarean delivery rates increased from 15% to 30% for infants of birthweights of 500-999 g, and from 39% to 52% for infants of birthweights of 1000-1499 g. In level-III hospitals, the proportion of live-born infants who did not receive active resuscitation fell from 32% to 18% for those who weighed 500-999 g, and from 28% to 15% for those who weighed 1000-1499 g. Time trends over the four years showed the management of very-low-birthweight infants to be in a state of rapid transition in all birth settings. At the same time there was a fall in the still-birth rate of infants of birthweights of 500-999 g. Still-births rates for infants of birthweights of 1000-1499 g remained unchanged, as did neonatal mortality rates in both weight groups.

Apgar Score↗
PubMed1990

Developmental regulation of specific protein interactions with an enhancerlike binding site far upstream from the avian very-low-density apolipoprotein II gene.

Expression of the avian very-low-density apolipoprotein II (apoVLDLII) gene is completely dependent on estrogen and restricted to the liver. We have identified binding sites for nonhistone nuclear proteins located between -1.96 and -2.61 kilobases. One of these sites, located at -2.6 kilobases (designated site 1), was found to span an MspI site that becomes demethylated between days 7 and 9 of embryogenesis, the stage of development at which competence to express the apoVLDLII gene begins to be acquired. Levels of the factor(s) involved were high at day 7 of embryogenesis, decreased two- to threefold by days 9 to 11, and continued to decline more slowly until hatching. Furthermore, the mobility of the complex formed underwent a well-defined shift between days 11 to 13 embryogenesis. Methylation interference studies showed that modification of the outer guanosines of the MspI site resulted in marked inhibition of the formation of the protein-DNA complex. Competition studies, fractionation of nuclear extracts, and tissue distribution indicated that the factor was not the avian homolog of hepatocyte nuclear factor 1, nuclear factor 1, or CCAAT/enhancer-binding protein (C/EBP). However, site 1 could complete for binding to an oligonucleotide, previously shown to be recognized by C/EBP, in a nonreciprocal fashion. These studies demonstrate that the sequence recognized by the protein includes a C/EBP consensus sequence but that elements in addition to the core enhancer motif are essential for binding.

Age Factors↗
PubMed1990

The Melbourne Chart--a logical guide to neonatal resuscitation.

Resuscitation of the asphyxiated infant is one of the great emergencies in medical practice. Properly done, it can save many lives and greatly reduce the morbidity resulting from hypoxic-ischaemic encephalopathy, but if it is ineptly performed, the effects of hypoxic-ischaemic encephalopathy may be accentuated, with resultant increased morbidity and even mortality. Other than paediatricians, few practitioners have regular experience in neonatal resuscitation: indeed many, including obstetricians, anaesthetists, general practitioners and midwives may only rarely face the problem of severe asphyxia. It is therefore essential for the occasional practitioner to have ready reference to a logical guide to resuscitation. We have designed such a guide which is widely distributed in delivery suites and operating theatres in Victoria. Its basic form has been in use for over a decade and it has recently been revised. Use of the chart assists the resuscitator to judge the level of resuscitation required. It is our experience that much unnecessary intervention occurs at resuscitation, and we believe the methods outlined in this schematic chart represent a more conservative but logical approach to neonatal resuscitation. The chart is based on the pathophysiological changes that occur in perinatal asphyxia, directing the user to the appropriate manoeuvres required to correct those changes, depending on the degree of asphyxia which is determined by clinical signs and by use of the Apgar score.

Apgar Score↗
PubMed1989

Observations on spinal dysraphism.

An attempt has been made to look into the age at presentation, incidence and clinical presentation of 40 patients with spinal dysraphism. Thirteen cases of myelomeningocele and 11 cases of meningocele constituted the 'aperta' group and there were 16 'occulta' cases. Though among the 'aperta' cases male is to female ratio was 1:1, a marked male preponderance of 2.2:1 was seen among 'occulta' cases. First born child was found to be most frequently (44.50%) affected in the present series. Myelography remained a mainstay in deciding operation in 'occulta' cases. All 'aperta' cases and 11 out of 16 'occulta' cases were treated by operation. Regarding results of treatment, all cases with meningocele were fully cured, cases with myelomeningocele showed no improvement but further deterioration of the neurological status could be arrested. Hydrocephalus was associated in 8 out of 13 cases with myelomeningocele and ventriculoperitoneal (VP) shunt were instituted in all of them. Prognostic significance of presence of hydrocephalus was profoundly grave as was evident from the mortality rate (10%) in this series.

Adolescent↗
PubMed1988

Increased mortality of preterm infants transferred between tertiary perinatal centres.

Over 18 months almost one quarter of infants born before 30 weeks' gestation in a tertiary perinatal centre who required intensive care had to be transferred to other tertiary centres because intensive care facilities were fully occupied. When infants with lethal congenital malformations were excluded half of the 34 infants who were transferred died; this was twice the mortality (24%) in the 111 infants remaining. The difference between the groups was significant (relative odds = 3.1) and remained so after adjustment for any discrepancies in gestational age (relative odds = 4.0). After adjustment for potential confounding variables by logistic function regression the risk of dying for those transferred remained significantly higher than that for infants who remained (relative odds = 4.6, 95% confidence interval 1.8 to 12.1). As the requirement for neonatal intensive care is episodic and unpredictable more flexibility has to be built into the perinatal health care system to enable preterm infants delivered in tertiary perinatal centres to be cared for where they are born.

Australia↗
PubMed1988

The survival of extremely-low-birthweight infants in Victoria: 1982-1985.

A population-based survey of mortality in extremely-low-birthweight (500- to 999-g) infants was carried out in Victoria for the years 1982 to 1985. No increase in the number of extremely-preterm births occurred during that time. The still-birth rate fell from 498 still births per 1000 births in 1982-1983 to 403 still births per 1000 births in 1984-1985. The neonatal mortality in 1982-1985 was 638 deaths per 1000 live births, with no significant decline from that of the 1978-1981 cohort. The small increase in neonatal survivors was not associated with any change in the postneonatal death rate. Delivery in a level-3 unit was associated with a significantly better outcome. Multiple births made a major contribution to the extremely-low-birthweight group of infants.

Birth Weight↗
PubMed1988

A novel insertion sequence in the cryptic plasmid of Neisseria gonorrhoeae may alter the B protein at the translational level.

A variant of the cryptic plasmid of Neisseria gonorrhoeae, 4.4 kb in size, was isolated and characterized at the molecular level. This variant harbored a 156-bp insertion which was located between coordinates 3134 and 3135 within the putative cppB gene using the 4.2-kb cryptic plasmid, pJD1, as a reference. The insertion contained a novel EcoRI site and several elements of symmetry (both direct and inverted repeats). Stop codons present in the insertion interrupted the coding capacity of the cppB gene. Although the insertion was within one of two previously characterized 44-bp repeats purportedly involved in site-specific recombination, it was distinct from a 54-bp segment deleted in some cryptic plasmids. The presence of the insertion suggests a mechanism of modulating the expression of the cppB gene at the translational level through DNA rearrangement.

Amino Acid Sequence↗
PubMed1987

Cranial ultrasound screening of preterm and term neonates.

A cranial ultrasound examination was performed between 48 and 96 h of age on 580 neonates of 25-42 weeks gestation. The incidence of cerebroventricular haemorrhage (CVH) in infants less than 32 weeks gestation was 37%, compared with an incidence of 2.7% in infants of 32 weeks or more. The incidence of CVH unselected healthy term infants (between 37 and 42 weeks) was only 1.1%. Of the 13 infants of 32 weeks or more who were found to have a haemorrhage, nine had a small (Grade I) haemorrhage (69%) and none of these infants had abnormal neurological signs in the neonatal period. The remaining four infants with Grade II, III or IV haemorrhage developed either seizures or episodes of apnoea. Two of the 13 infants of 32 weeks or more with a haemorrhage died, one during the newborn period and the other at 5.5 months of age. CVH in asymptomatic infants of 32 weeks or more gestation is uncommon and does not justify routine cranial ultrasound scanning.

Cerebral Hemorrhage↗
PubMed1985

Standard electromotive force of the H2-AgCl;Ag cell in 30, 40, and 50 mass% glycerol/water from -20 to 25 degrees C: pK2 and pH values for a standard "mops" buffer in 50 mass% glycerol/water.

Data are presented regarding the establishment of the pH (designated pH*) of a standard buffer solution suitable as a pH reference in 50 mass% glycerol/water mixtures at temperatures ranging from -20 to 25 degrees C. The buffer material selected was the ampholyte Mops [(3-N-morpholino)-propane sulfonic acid], and the reference standard consists of equal molal amounts of Mops and its sodium salt. The assignment of pH* values is based on measurements of the electromotive force (emf) of cells without liquid junction of the type: Pt;H2(g, 1 atm) / Mops, Na Mopsate, NaCl / AgCl;Ag and the pH* was derived from a determination of K2, the equilibrium constant for the dissociation process (Mops) +/- in equilibrium with (Mopsate)- + H+. The standard emf of the silver-silver chloride electrode in 30, 40, and 50 mass% glycerol/water mixtures was determined from emf measurements of the cell at subzero temperatures with HCl solutions replacing the buffer-chloride mixtures.

Buffers↗
PubMed1985

Acid dissociation constants and pH values for standard "bes" and "tricine" buffer solutions in 30, 40, and 50 mass% dimethyl sulfoxide/water between 25 and -25 degrees C.

Information is given concerning two standard buffer solutions suitable as pH references in 30, 40, and 50 mass% dimethyl sulfoxide (DMSO)/H2O mixed solvents at subzero temperatures from -20 to 0 degrees C, with the intention of establishing a pH (designated pH*) scale. The two buffers selected were the ampholytes N,N-bis(2-hydroxyethyl)-2-aminoethane sulfonic acid ("bes") and N-tris(hydroxymethyl)methylglycine ("tricine"), and the reference standard consisted of equal molal quantities of the buffer and its respective sodium salt. The assignment of pH* values was based on measurements of the emf of cells without liquid junction of the type: Pt;H2(g,l atm) /Bes, Na Besate, NaCl / AgCl;Ag and Pt;H2(g,l atm) /Tricine, Na Tricinate, NaCl /AgCl;Ag and the pH* was derived from a determination of K2, the equilibrium constant for the dissociation process (Buffer)+/- in equilibrium with(Buffer)- + H+.

Alkanesulfonates↗
PubMed1985

Perinatal factors, periventricular haemorrhage and mortality in very low birthweight infants.

In a population of 225 very low birthweight infants born over a 21 month period the cerebroventricular system was scanned by ultrasound. One third of the infants developed a periventricular haemorrhage; in 41% of infants the haemorrhage was detected before an hour of age and 66% of all haemorrhages occurred within the first 24 hours. Statistically significant associations with periventricular haemorrhage included vaginal delivery, endotracheal intubation and intravenous sodium bicarbonate when this was administered in the first 24 hours. In a stepwise regression analysis, however, these and other potentially significant variables added little to the total accountable variance. A similar analysis of perinatal factors and mortality revealed that decreasing gestation was the major association with death.

Bicarbonates↗
PubMed1985

Ventricular size in newborn infants.

Cranial ultrasound examinations were performed on 533 infants of between 48 and 96 hours of age to establish the range of ventricular size in neonates of different gestational ages in whom there was no evidence of intraventricular hemorrhage or neural tube defects. It was found that ventricular size did not vary in infants with gestational age of 26 weeks or more. Only 15 (2.8 per cent) neonates had a ventricular width of greater than 3 mm. Of these 15 infants, 13 were re-examined within the first year of life and found to be neurologically and developmentally normal.

Anthropometry↗
PubMed1984

Standard electromotive force of the H2-AgCl;Ag cell in 30, 40, and 50 mass% dimethyl sulfoxide/water from -20 to 25 degrees C: pK2 and pH values for a standard "Bicine" buffer solution at subzero temperatures.

The establishment of the pH (designated pH*) of a standard buffer solution suitable as a pH reference in 30, 40, and 50 mass% dimethyl sulfoxide (DMSO)/H2O mixtures at temperatures in the range -20 to 0 degrees C is reported. The buffer material selected was the ampholyte Bicine (N,N-bis(2-hydroxyethyl)glycine), and the reference standard consists of equal molal quantities of Bicine and its sodium salt. The assignment of pH* values rests on measurements of the emf of cells without liquid junction, Pt;H2(g, 1 atm) [Bicine, Na Bicinate, NaCl [AgCl;Ag, and the pH* was derived from a determination of K2, the equilibrium constant for the dissociation process (Bicine) +/- in equilibrium (Bicinate)- + H+. The standard emf in the DMSO/H2O solvents at subzero temperatures was determined from emf measurements of the cell with solutions of HCl replacing the buffer-chloride mixture.

Buffers↗
PubMed1983

Provision of perinatal services and survival of extremely low birthweight infants in Victoria.

The transfer of at-risk mothers to one of the three Level III maternity hospitals in Victoria has been promoted since 1975; since 1978, the Newborn Emergency Transport Service has been available throughout the State for the transport of infants to the four Level III neonatal units. By means of data from multiple sources, we ascertained the one-year survival of infants with birthweights of between 500 g and 999 g born in Victoria between 1978 and 1981. Of 711 live-born infants, 227 (31.9%) survived 28 days and 210 (29.5%) lived to at least one year of age; of 490 infants born in the Level III maternity units, 156 (31.8%) lived. There were 54 (24.4%) survivors among the 221 infants born elsewhere; all these survivors were included in the group of 105 babies who had been transferred after birth to Level III neonatal units. Although only 25.5% of all births for the State occurred in the Level III maternity hospitals, 69% of all infants who weighed between 500 g and 999 g at birth were delivered in these hospitals. The transfer of the mother or the new born baby to a Level III unit was possible in an additional 48 cases. Although survival rates from Level III hospitals may possibly improve in the future, the shortage of ventilator beds remains a practical obstacle.

Australia↗
PubMed1983

The 5' noncoding and flanking regions of the avian very low density apolipoprotein II and serum albumin genes. Homologies with the egg white protein genes.

We have isolated and sequenced the 5' proximal exons and flanking regions of the chicken very low density apolipoprotein II (apo-VLDLII) and serum albumin genes. These genes specify the most abundant mRNA species present in livers of hens or estrogen-treated roosters. Sequencing revealed that the promoter region of the estrogen-dependent apo-VLDLII gene contained at least two potential transcriptional initiation sites, preceded by appropriately positioned "ATA" sequences. One is homologous with the cap site of the ovalbumin gene, and the other exhibits a match of 10 out of 12 nucleotides with the cap site of the serum albumin gene. S1 nuclease mapping indicates that both sites are active in vivo, although the "ovalbumin"-like site is by far the most efficient at all stages of the estrogenic response. The relative efficiencies of these two sites are maintained during in vitro transcription of truncated templates. A third site, that was not anticipated from sequencing data, is active in vivo but inactive in vitro. A conserved 5' flanking element, initially identified during studies on egg white protein genes, is also present upstream from the apo-VLDLII and serum albumin genes. Its removal does not affect initiation site selection in vitro. Regions of the apo-VLDLII and ovalbumin genes extending 100 nucleotides downstream from the "TATA box" contain several striking homologies that suggest a common mode of evolution.

Amino Acid Sequence↗