PubMed Health⌕ Search

Biomedical subjects

R Joseph

Publications and source records attributed to R Joseph.

At least 19 recordsLinked to original sources
PubMed1996

Cloning of human neuronatin gene and its localization to chromosome-20q 11.2-12: the deduced protein is a novel "proteolipid'.

Human brain development is a continuum governed by differential gene expression. Therefore, we proceeded to identify genes selectively expressed in the developing brain. Using differential display and library screening, a novel rat cDNA, neuronatin, was identified and used to screen a human fetal brain cDNA library. Human neuronatin cDNA was isolated and sequenced. The cDNA was 1159 bp long and corresponded in size to the 1.25 kb message detected on Northern analysis. Neuronatin mRNA was selectively expressed in human brain during fetal development, but became repressed in adulthood. When studied in the rat, neuronatin mRNA first appeared at mid-gestation in association with the onset of neurogenesis, becoming most pronounced later in development when neuroepithelial proliferation and neuroblast commitment are manifest, and declined postnatally coinciding with the completion of neurogenesis. The deduced protein has two distinct domains, a hydrophobic N-terminal and basic C-terminal rich in arginine residues. Both the amino acid sequence and secondary structure of this amphipathic polypeptide exhibited homology to PMP1 and phospholamban, members of the "proteolipid' class of proteins which function as regulatory subunits of membrane channels. The neuronatin gene, 3973 bases long, contains in its 5'-flanking region a neural restrictive silencer element which may govern neuron-specific expression. Based on screening a somatic cell hybrid panel, neuronatin gene was assigned to chromosome-20. And, using deletion constructs of chromosome-20 and fluorescence in situ hybridization, neuronatin was localized to chromosome-20q11.2-12. In conclusion, neuronatin is a novel human gene that is developmentally regulated and expressed in the brain. The deduced protein is a proteolipid that may function as a unique regulator of ion channels during brain development. The definitive localization of neuronatin to human chromosome 20q11.2-12 provides the basis to investigate this gene as a candidate in neuro-developmental diseases that may also map to this region.

Amino Acid Sequence↗
PubMed1996

Structure and organization of the human neuronatin gene.

Neuronatin is a brain-specific human gene that we recently isolated and observed to be selectively expressed during brain development. In this report, the genomic structure and organization of human neuronatin is described. The human gene spans 3973 bases and contains three exons and two introns. Based on primer extension analysis, a single cap site is located 124 bases upstream from the methionine (ATG) initiation codon, in good context, GAACCATGG. The promoter contains a modified TATA box, CATAAA (-27), and a modified CAAT box, GGCGAAT (-59). The 5'-flanking region contains putative transcription factor binding sites for SP-1, AP-2 (two sites), delta-subunit, SRE-2, NF-A1, and ETS. In addition, a 21-base sequence highly homologous to the neural restrictive silence element that governs neuron-specific gene expression is observed at -421. Furthermore, SP-1 and AP-3 binding sites are present in intron 1. All splice donor and acceptor sites conformed to the GT/AG rule. Exon 1 encodes 24 amino acids, exon 2 encodes 27 amino acids, and exon 3 encodes 30 amino acids. At the 3'-end of the gene, the poly(A) signal, AATAAA, poly(A) site, and GT cluster are observed. The neuronatin gene is expressed as two mRNA species, alpha and beta, generated by alternative splicing. The alpha-form contains all three exons, whereas in the beta-form, the middle exon has been spliced out. The third nucleotide of all frequently used codons, except threonine, of neuronatin is either G or C, consistent with codon usage expected for Homo sapiens. This information about the structure of the human neuronatin gene will help in understanding the significance of this gene in brain development and human disease.

Amino Acid Sequence↗
PubMed1996

Comparison of methods for measuring albumin in peritoneal dialysis and hemodialysis patients.

Serum albumin levels have been used extensively as an indicator of morbidity in patients with end-stage renal disease. Recent evidence suggests that albumin levels vary considerably in hemodialysis patients depending on the laboratory method used, but formulas for comparing albumin values by different methods have not been developed. We prospectively evaluated the effects of measuring albumin by three different methods on paired plasma and serum from 23 patients on continuous ambulatory peritoneal dialysis (CAPD) and 53 patients on chronic maintenance hemodialysis. Plasma and serum gave virtually identical results independent of method used. In CAPD patients, bromcresol green and nephelometry gave nearly identical albumin measurements through the entire range of plasma levels. In contrast, bromcresol purple gave values that were 9.9 percent +/- 1.3 percent lower (P < 0.05). Hemodialysis patients showed a similar pattern with close agreement between bromcresol green and nephelometry, but bromcresol purple gave lower albumin levels by 19.1 percent +/- 1.2 percent (P < 0.05). The discrepancy in albumin in CAPD patients was significantly less than in the hemodialysis patients (P < 0.05), suggesting that there were fewer interfering substances in the blood of CAPD patients than in hemodialysis patients. Linear regression analysis was used to develop simple formulas for comparing albumin values obtained by the different methods in CAPD and hemodialysis patients. These studies show that values for albumin in blood vary significantly by method of analysis in CAPD and hemodialysis patients. By the use of these formulas, it becomes possible to compare albumin values between centers using different methods for the purpose of quality management.

Adult↗
PubMed1996

Fetal and neonatal haemodilution associated with multiple placental chorioangioma: case report.

A pregnancy with polyhydramnios and abnormal antepartum fetal heart rate pattern was found to have multiple placental haemangiomas. Multiple placental haemangiomas can give rise to fetal cardiac failure due to a hyperdynamic circulation or fetal anaemia either due to haemodilution or possibly destruction of blood cells in the chorioangioma. Whether fluid restriction with or without diuretics or blood transfusion is the correct form of treatment of neonatal cardiac failure in such a case is discussed.

Adult↗
PubMed1996

Cervical cytology screening. How can we improve rates among First Nations women in urban British Columbia?

OBJECTIVE: To determine Pap smear screening rates among urban First Nations women in British Columbia; to identify facilitators and barriers; and to develop, implement, and evaluate specific interventions to improve Pap smear screening in Vancouver. DESIGN: Computer records of band membership lists and the Cervical Cytology Screening Program registry were compared to determine screening rates; personal interviews and community meetings identified facilitators and barriers to urban screening programs. A community advisory committee and the project team collaborated on developing specific interventions. SETTING AND PARTICIPANTS: Purposive sample of British Columbia First Nations women, focusing on women living in Vancouver. INTERVENTIONS: Poster, art card, and follow-up pamphlet campaign; articles in First Nations community papers; community meetings; and Pap smear screening clinics for First Nations women. MAIN OUTCOME MEASURES: Pap smear screening rates among BC First Nations women according to residence and reasons for not receiving Pap smears. RESULTS: Pap smear screening rates were substantially lower among First Nations women than among other British Columbia women; older women had even lower rates. No clear differences were found among First Nations women residing on reserves, residing in Vancouver, or residing off reserves elsewhere in British Columbia. Facilitators and barriers to screening were similar among women residing on reserves and in Vancouver. Many First Nations women are greatly affected by health care providers' attitudes, abilities to provide clear information, and abilities to establish trusting relationships. CONCLUSIONS: Family physicians are an important source of information and motivation for Pap smear screening among First Nations women.

Adolescent↗
PubMed1995

Neuronatin mRNA: alternatively spliced forms of a novel brain-specific mammalian developmental gene.

Neurogenesis begins with the closure of the neural tube around mid gestation and continues in the rat for about two weeks postnatally. Therefore, we investigated the role of neuronatin, a novel cDNA that we cloned from neonatal rat brain (Joseph et al., Biochem. Biophys. Res. Commun., 201 (1994) 1227-1234), in brain development. Further studies described in the present manuscript, lead to the identification of two alternatively spliced forms of neuronatin mRNA, alpha and beta, with the same open reading frame. Neuronatin-alpha encoded a novel protein of 81 aa, and the beta-form encoded 54 aa. Both forms were identical, except that the alpha-form had an additional 81 bp sequence inserted into the middle of the coding region. On Northern analyses, neuronatin mRNA was relatively selective for the brain. It first appeared at E11-14, a time when the neural tube has closed and neuroepithelial proliferation initiated, became pronounced at E16-19 with a surge in neurogenesis, and declined postnatally to adult levels with the completion of neurogenesis. In order to determine whether there were other forms of neuronatin mRNA, and to study the expression of the alpha and beta forms separately during development, reverse transcriptase-polymerase chain reaction was carried out using primers flanking the coding region of the alpha and beta forms. The RT-PCR results clearly indicated that there were only two forms of neuronatin. The beta-form first appeared at E11-14, whereas the alpha-form was present even earlier at E7-10. Together, these findings indicate that the two forms of neuronatin mRNA are regulated differently during brain development.(ABSTRACT TRUNCATED AT 250 WORDS)

Alternative Splicing↗
PubMed1995

Unusual biphasic melting behaviour of Rhodotorula gracilis DNA.

Ultraviolet, fluorescence and CD spectral analysis suggested unusual structural features of Rhodotorula gracilis ATCC 90950 DNA. R. gracilis DNA exhibited 13% hyperchromicity at 260 nm as against 26% shown by calf thymus DNA. The biphasic melting curve, one phase between 88-92 degrees C and the other between 92-97 degrees C, was attributed to different unwinding pattern of R. gracilis DNA as a function of rise in temperature. The binding affinity of ethidium bromide to R. gracilis DNA determined was almost the same as that of calf thymus DNA. Fluorescence spectra with rise in temperature showed decrease in the quanta of fluorescence intensity after transition temperature, suggesting the quenching due to variation in structure. The CD spectra of R. gracilis DNA did not resemble the spectra of any of the known DNA forms and it showed increase in the magnitude of negative band with rise in temperature suggesting a B-C transition. Disruption of intermolecular and higher order structures by sonication and salt concentration did not change this behaviour implicating the influence of sequence and base composition of R. gracilis DNA on thermal melting transition.

Circular Dichroism↗
PubMed1995

Exon organization and sequence of the genes encoding alpha-lactalbumin and beta-lactoglobulin from the tammar wallaby (Macropodidae, Marsupialia).

Clones encompassing the genes encoding alpha-lactalbumin and beta-lactoglobulin were isolated from a tammar wallaby genomic library, the exons localized using end-labeled oligonucleotides and the DNA sequences determined. The tammar beta-lactoglobulin gene has the same 7 exon-6 intron structure as the sheep homologue. Potential binding sites for mammary gland-specific transcription factors were identified, on the basis of similarity to sites in the sheep gene, in the promoter region of the tammar beta-lactoglobulin gene. The tammar gene encoding alpha-lactalbumin appears to contain four introns rather than three as are present in the eutherian homologues, or the evolutionarily related lysozyme gene. The additional intron appears to occur within the 5' noncoding region of the tammar gene.

Amino Acid Sequence↗
PubMed1995

Growth pattern of the Indian fetus.

OBJECTIVES: To determine the pattern of intrauterine growth and the gestation at birth of Indian fetuses. METHOD: One hundred twenty consecutive women who had reliable menstrual histories, low-risk pregnancies and who were booked for delivery at the Christian Medical College Hospital, Vellore, before 20 weeks' gestation were recruited to the study. Ultrasound fetal biometry was carried out at 4-weekly intervals from 20 weeks and at weekly intervals after 36 weeks until delivery. RESULTS: Growth patterns of fetal biparietal diameter and femur length were comparable to those reported in Western populations. However there was a lag in growth of abdominal circumference (AC) after 28 weeks in comparison with that reported in Western populations. The median gestation at delivery following spontaneous labor was 39 weeks. No association was observed between rate of growth of AC and gestation at birth. CONCLUSION: Slowing of growth of the fetal AC after 28 weeks and a shorter length of gestation result in the birth of smaller babies in this ethnic group. The implications of these findings are discussed.

Adult↗
PubMed1995

p23 transplantation antigen mRNA is differentially expressed in human fetal brain.

As gene expression governs development, we attempted to isolate differentially expressed genes in fetal and adult human brain. RNA samples extracted from adult and 18-24-week-old fetal human brain were reverse transcribed, amplified using twenty combinations of 3'-anchored primers and degenerate 5'-primers, and the resulting cDNA fragments separated on denaturing polyacrylamide gels. Thereafter, 45 (H1-H45) differentially displayed cDNA bands were extracted from the gels, amplified by polymerase chain reaction, and used as probes to detect their mRNA by northern blotting. One of these fragments, H8, confirmed on northern blotting to be highly expressed in fetal brain, was cloned and sequenced. This fragment was homologous to wild type p23 human transplantation antigen. This is phylogenetically a well conserved gene and appears to play an important role in cell growth. Even a single point mutation in the mouse gene results in cell destruction secondary to a cytotoxic T-lymphocyte response. Therefore, our finding that normal human fetal brain expresses high levels of wild type p23 transplantation antigen may have importance in maintaining cell growth during human brain development.

Antigens, Neoplasm↗
PubMed1995

The pruritogenic and inflammatory effects of prostanoids in the conjunctiva.

The therapeutic utility of cyclooxygenase (CO) inhibitors, such as ketorolac, in reducing the inflammatory events associated with allergic conjunctivitis is not unexpected since prostanoids (PG) elicit conjunctival redness (PGD2, PGE2, PGF2 alpha), edema (PGD2, TxA2), eosinophil infiltration (PGD2, PGJ2) and mucous cell discharge (PGD2, PGJ2, TxA2). Recently, topically administered ketorolac has also been reported to alleviate the itching associated with allergic conjunctivitis. This was viewed as intriguing since CO inhibitors are not regarded as useful for treating itching dermatoses and PGs do not elicit itching when applied to the skin. In order to investigate the antipruritic activity of ketorolac, we developed a model for reproducibly measuring ocular surface itch responses. The model involves itch-scratch responses to pruritogens applied locally to the ocular surface. Painful and foreign body stimuli do not produce an itch-scratch response. Unlike reported skin studies, PGE2 was a potent itch-producing substances in the conjunctiva. PGD2 was weakly pruritogenic but PGF2 alpha and the TxA2-mimetic U-46619 were inactive. The PG precursor arachidonic acid was also a potent pruritogen and its effects were inhibited by ketorolac pretreatment. Ketorolac also dose-dependently inhibited the itching associated with experimental allergic conjunctivitis. It appears that PGs are potent itch-producing substances in the conjunctiva and the anti-itch efficacy of ketorolac in allergic conjunctivitis appears to involve inhibition of conjunctival PG biosynthesis from arachidonic acid.

Animals↗
PubMed1995

Prospects for the secondary prevention of colorectal cancer: screening by flexible sigmoidoscopy?

It may be useful to draw an analogy between the proposed screening programme for colorectal cancer and the cervical cancer screening programme. Both tumours show a spectrum of histological abnormalities consistent with a premalignant phase. The natural history of these premalignant lesions is poorly understood and although some will progress, if untreated, to invasive disease, most will not. Light microscopy cannot confidently distinguish which cases will progress and which will regress, and clinicians are therefore obliged to treat all. This will result in the destruction of many lesions of uncertain malignant potential. The secondary prevention of cervical cancer, although therapeutically efficacious, is inefficient. A lack of understanding of the natural history of intraepithelial neoplasia has frustrated attempts to develop rational referral criteria, and it is only now that the appropriate trials are being undertaken. The development of outpatient investigative and therapeutic procedures has resulted in many more women being referred for investigation and treatment, with predictable pressure on other services offered by gynaecologists, but no demonstrable saving of life. Similar uncertainties surround a screening programme for colorectal cancer. The principal concerns are not about the efficacy of polypectomy in interrupting the polyp cancer sequence, although uncertainties about the frequency with which cancer arises de novo do require that the effectiveness of this intervention is formally tested. Our major concerns are with compliance, and the management of the individual who tests positive--that is, who is found to have a distal polyp. Technological advances and operator enthusiasm may, as has happened with the cervical screening programme, lead to a relaxation in the indications for further investigation and treatment. Such a development would affect resources substantially if a population screening programme were in place. Nevertheless, there are grounds for believing that a screening programme for colorectal cancer, using sigmoidoscopy, might be successful in certain age groups if compliance was satisfactory. The scale of benefits may be comparable with those achieved by the breast screening programme. Our limited cost analysis, which relates to only to specific items of clinical activity, suggest that the mean cost for each case of cancer prevented will be about 8000 pounds sterling. These conclusions suggest that screening by flexible sigmoidoscopy merits serious consideration. It is also imperative, however, that consideration should be given to resolving some of the uncertainties about the clinical management and surveillance of those found to have distal polyps.

Age Factors↗
PubMed1995

Towards improved perinatal care--perinatal audit.

Perinatal audit is a measure of quality of care given in pregnancy and it gives an idea as to how the resources need to be allocated for better outcome. The perinatal mortality data in the National University Hospital over a 7-year period (1986-1992) were compiled and compared with that of the year 1982. The perinatal mortality rate (PNMR) of 14.6/1000 in 1982 declined to 8.9/1000 for the period 1986 to 1992 and the reduction was noticeable in all ethnic groups, particularly in the Malays. When lethal congenital malformations (LCMs) were excluded, the PNMR decreased to 5.7/1000. Such reduction is due to easy availability and acceptance of antenatal care, improvement in antenatal and intrapartum fetal surveillance and advances in neonatal care. Neonatal audit was extended beyond the first 7 days of birth which showed that the majority (65%) of deaths occurred in the first week and 15% occurred after the first month. The fear that intensive neonatal care serves to postpone death is not entirely substantiated. There was nearly a ten-fold rise in PNMR between the non-low birthweight and low birthweight groups. The important causes of perinatal mortality during the review period were LCMs (35.7%), complications of prematurity (17.9%) and asphyxia (15.3%). No cause was identifiable in 28.5%. Detailed analysis revealed that the standard of care could have been improved in a third of the cases (83/235) which could have led to further reduction of perinatal mortality rate.

Asphyxia Neonatorum↗
PubMed1995

The normal preterm foetal heart rate pattern.

A longitudinal study was carried out on 38 women with low risk pregnancies. These women had cardiotocography at 27-28 wk initially, at fortnightly intervals thereafter until 36 wk and at weekly intervals thereafter until delivery. All cardiotocographs were analyzed by one investigator who was not aware of the individual clinical situation. Of the 232 cardiotocographs, 12 (0.5%) of poor quality were excluded from analyses. The mean base-line heart rate decreased from 142.5 (SD 6.03) beats per min at 27-30 wk to 138.2 (SD 7.4) at term. Analysis of variance for repeated measures showed that the decrease in foetal heart rate with gestation was statistically significant (P < 0.001). The number of accelerations increased with gestation (P = 0.002). There were no significant changes in variability and decelerations with increasing gestation.

Female↗
PubMed1994

Molecular cloning of a novel mRNA (neuronatin) that is highly expressed in neonatal mammalian brain.

As differential gene expression governs the progression of development into senescence, we attempted to define the genes that are selectively expressed during postnatal brain development. A cDNA fragment selectively expressed in neonatal rat brain was identified by differential display and used to screen a cDNA library prepared from the same mRNA sample. The full length cDNA, neuronatin, was 1195bp long and coded for a novel protein of 81 amino acids. The cDNA detected an mRNA species of similar size that was highly expressed in rat neonatal and human fetal brain. The deduced protein exhibited a hydrophobic N-terminal and hydrophilic C-terminal, suggesting that it is membrane bound and might function in signal transduction. The selective expression of this novel mRNA in late fetal and early postnatal brain development, and loss of expression in adulthood and senescence, suggests that downregulation of neuronatin may be involved in terminal brain differentiation.

Age Factors↗
PubMed1994

The identification of nuclear and mitochondrial genes by sequencing randomly chosen clones from a marsupial mammary gland cDNA library.

To increase the number of genes that can be mapped to the genome of the tammar wallaby (Macropus eugenii), we sequenced 100 randomly chosen clones from a mammary gland cDNA library. Provisional identifications were made of seven nuclear genes and one mitochondrial gene encoding two caseins, beta-galactosidase, acetyl-coenzyme A synthetase, lipoprotein lipase, inorganic pyrophosphatase, an ATP-dependent RNA helicase, and cytochrome c oxidase I. Highly conserved genes, such as that encoding acetyl-coenzyme A synthetase, were easily identified even from cross-kingdom matches. Genes which are highly divergent, however, such as those encoding the mature casein peptides, could not be aligned with homologues in the databases. Even in an organ where there is high mRNA species redundancy, the sequence characterization of expressed sequence tags provides a rapid means of gene identification for mapping purposes.

Amino Acid Sequence↗
PubMed1994

Double staining in situ study of mRNAs encoding milk proteins in the mammary gland of the tammar wallaby (Macropus eugenii).

Oligonucleotides, differentially tagged with fluorochromes, were used to determine whether the distribution of mRNAs encoding the major milk proteins is heterogeneous within the mammary gland of the tammar wallaby (Macropus eugenii). This method also allowed direct visualization of two species of mRNA within the same cell. Sections of early and late lactating glands of tammar wallabies were hybridized with oligonucleotides labelled with fluorescein isothiocyanate or rhodamine isothiocyanate either alone or in combination. The results support the hypothesis that milk secretion is an all-or-none process with all epithelial cells in a given alveolus producing the same suite of milk proteins. In tammar wallabies, a gene encoding a protein specific to the latter phase of lactation appears to be expressed in those cells already secreting the other major milk proteins.

Animals↗