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Biomedical subjects

D Rowe

Publications and source records attributed to D Rowe.

At least 91 records · Page 5Linked to original sources

Construction of DNA sequences complementary to rat alpha 1 and alpha 2 collagen mRNA and their use in studying the regulation of type I collagen synthesis by 1,25-dihydroxyvitamin D.

Type I collagen mRNA from fetal rat calvaria was used as a template for the synthesis of a cDNA that was subsequently inserted in the PstI site of the plasmic vector pBR322 and cloned. Three recombinant plasmids containing type I collagen specific sequences were characterized: p alpha 1R1 is 1600 bp and spans approximately 500 amino acid residues within the triple helical region of alpha 1(I) and p alpha 1R2 is 900 bp in size and covers the entire 3' noncoding and about half of the C-terminal propeptide region of alpha 1(I) collagen mRNA. The third recombinant p alpha 2R2 is 1500 bp and contains alpha 2(I) sequences specific for the entire 3' noncoding and C-terminal propeptide region. Partial nucleic acid sequence data revealed that the decreasing order of amino acid and nucleotide homology to similar regions of the rat cDNA was mouse greater than human greater than chick. Northern hybridization of mRNA after electrophoresis in 0.8% agarose revealed two distinctly different molecular weight patterns characteristic of alpha 1(I) (4.7 and 5.7 kb) and alpha 2(I) (4.2 and 4.5 kb) collagen mRNA when hybridized with the corresponding cDNA probe. Despite the high degree of sequence homology, DNA probes from rat or human produced a significantly reduced hybridization signal when used as an interspecies hybridization probe than to its corresponding mRNA. The rat cDNA probes were used in a dot hybridization assay to measure the type I collagen mRNA content in the fetal rat calvaria.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗

Specific thromboxane synthetase inhibition and albumin excretion rate in insulin-dependent diabetes.

Albumin excretion rates (AER) were measured in 30 insulin-dependent diabetics during a 16-week double-blind, randomised, placebo-controlled study of the specific thromboxane synthetase inhibitor UK-38,485.6 of 15 subjects in the active group had microalbuminuria (defined as mean pretreatment AER 20-150 micrograms/min); in these patients AER fell from 32 +/- 3 micrograms/min to 11 +/- 1 micrograms/min at 8 weeks and 9 +/- 1 micrograms/min at 16 weeks. The AER rose again (to 29 +/- 8 micrograms/min) within 12 weeks of stopping the drug. There was no significant change in the 10 patients with microalbuminuria who received placebo. There was a strong correlation between change from baseline values and the baseline values themselves in the active, but not in the placebo group, and the change from baseline differed significantly between the two groups. There was no change in glycosylated haemoglobin or mean blood glucose levels during the study. In a separate study UK-38,485 caused significant suppression of thromboxane B2 synthesis in diabetic and non-diabetic subjects.

Adult↗

Hypophosphatemia and hypercalciuria in small premature infants fed human milk: evidence for inadequate dietary phosphorus.

Phosphorus and calcium balance was measured prospectively in stable premature infants (less than or equal to 1600 gm) fed human milk or a standard commercial formula. Throughout the study, the P and Ca intakes of the infants fed human milk were two to three times less than those of infants fed formula. Infants fed human milk showed low serum P and normal serum Ca concentrations, complete renal reabsorption of P, and elevated renal Ca excretion. The net effect in infants fed human milk was a 50% reduction in the P and Ca retention, compared with the formula-fed group. Despite the unfavorable P and Ca balance in the group fed human milk, the only evidence of rickets was elevated alkaline phosphatase activity. Nevertheless, based on the biochemical changes in these infants, low serum P values, and excess urinary calcium losses, we conclude that the stable small premature infant fed human milk exclusively is deficient in phosphorus and only slightly more sufficient in calcium.

Bottle Feeding↗

Presence of translatable mRNA for pro alpha 2(I) chains in fibroblasts from a patient with osteogenesis imperfecta whose type I collagen does not contain alpha 2(I) chains.

RNA was extracted from the cultured fibroblasts from a patient with osteogenesis imperfecta previously shown to have type I collagen lacking alpha 2(I) chains. When the RNA was examined in a cell-free translation system from reticulocytes, the translation products included both pro alpha 1(I) and pro alpha 2(I) chains. When the poly(A)-enriched polysomal RNA was examined by blot hybridization with cDNAs for pro alpha 1(I) and pro alpha 2(I) chains, mRNAs for both pro alpha 1(I) and pro alpha 2(I) were seen. The ratio of mRNAs for pro alpha 1(I) to mRNAs for pro alpha 2(I) was about the same in the patient's fibroblasts as in control fibroblasts. The results suggested that the absence of pro alpha 2(I) chains in the type I pro-collagen from this patient is probably explained by a mutation which alters the structure of pro alpha 2(I) chains and thereby prevents incorporation of the pro alpha 2(I) chains into triple-helical procollagen.

Cell-Free System↗

Confirmation that the type I collagen gene on chromosome 17 is COL1A1 (alpha 1(I), using a human genomic probe.

A cloned 15 kb genomic fragment from the human alpha 1(I) collagen gene (COL1A1) has been used as a probe on restriction digests of DNA from human-mouse somatic cell hybrids. Positive results on hybrids containing chromosome 17 as their only karyotypically visible human material confirm the assignment of this gene to chromosome 17. Hybrids which contain fragments of chromosome 17 are used to confirm the localization to 17q21-qter.

Animals↗

An immunohistological study of secondary Sjögren's syndrome.

The labial biopsies from 13 patients with secondary Sjögren's syndrome (SS) and four disease controls were examined with a panel of monoclonal antibodies to human leucocyte antigens. Large numbers of T cells were found in most of the biopsies. In seven SS patients the T helper/inducer subset was found to be predominant. Antibody to HLA class I antigens consistently stained leucocytes, but other cell types stained more variably. Although the staining with antibody to HLA class II antigen was often weak, approximately as many cells stained with this antibody as with an antileucocyte antibody, implying that the T cells were activated. Anti-IgD revealed membrane staining of a corona of IgD-positive cells in structures resembling germinal centres. Isolated cells throughout the sections also showed strong cytoplasmic staining with anti-IgD. These results suggest a role for T-cell-dependent local antibody synthesis in the pathogenesis of the disease.

Adult↗

Plasma zinc in psoriasis: relation to surface area involvement.

Plasma zinc, serum albumin and alkaline phosphatase (a zinc-dependent enzyme) were measured in thirty-five psoriatics and their age- and sex-matched controls. No significant difference was seen between these two groups as a whole, but psoriatics with less than 10% surface involvement had significantly higher mean plasma zinc levels than their respective control group. Psoriatic patients also showed a relationship between the extent of surface involvement and the plasma zinc level, those with more extensive involvement having lower levels than those with minimal involvement. The differences were not due to disturbances in serum albumin, and no abnormalities in serum alkaline phosphatase were observed.

Adult↗

Monoclonal antibodies to human leucocyte antigens in polymyositis and muscular dystrophy.

Biopsy specimens from patients with treated or untreated polymyositis and muscular dystrophy controls were examined by indirect immunoperoxidase staining with a panel of monoclonal antibodies to human leucocyte antigens. In untreated polymyositis, helper/inducer T cells were the predominant T cell subset. In treated cases few T cells were seen. Overall, few T cells were seen in dystrophic cases, most infiltrating cells being dendritic and lacking T cell antigens. Staining of sarcolemma with anti-HLA class 1 antibody is weak or negative except in areas adjacent to infiltrating leucocytes or where muscle fibre damage is apparent.

Adult↗

Low ocular rigidity in patients with osteogenesis imperfecta.

Sixteen patients with osteogenesis imperfecta (OI) have undergone a thorough eye examination. These patients had statistically significantly lower ocular rigidity measurements than a group of normal volunteers matched on age, sex, and refractive error. In addition, the corneal diameter and length of the eyeball was smaller in OI patients than that in controls. Possible correlations of low ocular rigidity with biochemical changes in scleral collagen await further investigation.

Adolescent↗

Aging--a jewel in the mosaic of life. 15th Lenna Frances Cooper Memorial Lecture.

It is time to disabuse ourselves of the prevalent negative stereotypes and myths about aging. More people are living to an older age without the handicap of disease--and many of them are living independent, satisfying lives. True, there are old people who are loney, sick, and /or poor, but they are the minority. Nevertheless, they cannot be forgotten. There is an urgency to try to make their lives better. By ridding society of these negative stereotypes, better progress in the field of gerontology can be made. With nutrition woven so intimately into the fabric of satisfying living, opportunities beckon to the dietitian to provide service to the elderly. Done effectively, such service can add to the quality of life of all older persons, so that the later years can have dignity and meaning and indeed become a jewel in the mosaic of life.

Aged↗

Biophysical studies of infectious pancreatic necrosis virus.

The molecular weight of infectious pancreatic necrosis virus (IPNV) has been determined by analytical ultracentrifugation and dynamic light scattering. The sedimentation coefficient of the virus was found to be 435S. The average value for molecular weight is (55 +/- 7) x 106. The virus genome consists of two segments of double-stranded RNA (molecular weights, 2.5 x 106 and 2.3 x 106), which represents 8.7% of the virion mass. The capsid protein moiety of IPNV consists of four species of polypeptides, as determined by polyacrylamide gel electrophoresis. The number of molecules of each polypeptide in the virion has been determined. There are 22 molecules of the internal polypeptide alpha (molecular weight, 90,000), 544 molecules of the outer capsid polypeptide beta (molecular weight, 57,000), and 550 and 122 molecules, respectively, of the internal polypeptides gamma1 (molecular weight, 29,000) and gamma2 (molecular weight, 27,000). IPNV top component contains only the beta polypeptide species, and its molecular weight is estimated to be 31 x 106. The hydrodynamic diameter and electron microscopic diameter (calculated by catalase crystal-calibrated electron microscopy) of IPNV was compared with those of reovirus and encephalomyocarditis virus. Due to the swelling of the outer capsid, reovirus particles were found to be much larger when hydrated (96-nm diameter) than when dehydrated (76-nm diameter), having a large water content content and low average density. In contrast, IPNV particles are more rigid, having nearly the same average diameter under hydrous (64 nm) as under anhydrous conditions (59.3 nm). Encephalomyocarditis virus has a very low water content and does not shrink at all when prepared for electron microscopy.

Animals↗

Peptide map comparison of infectious pancreatic necrosis virus-specific polypeptides.

An investigation of virus-specific protein synthesis in infectious pancreatic necrosis virus (IPNV)-infected rainbow trout gonad cells was undertaken to find a relationship between the coding capacity of the virus genome (two segments of double-stranded RNA of 2.5 x 10(6) and 2.3 x 10(6) molecular weight) and the sizes and relative amounts of virus-specific proteins. Using polyacrylamide slabgel electrophoresis and autoradiography, eight distinct virus-specific polypeptides were detected in infected, [(35)S]methionine-labeled cells. These proteins may be grouped into three size classes on the basis of molecular weight: (i) large, alpha (90,000); (ii) medium, beta(1) (59,000), beta(2) (58,000), and beta(3) (57,000); and (iii) small, gamma(1) (29,000), gamma(1A) (28,000), gamma(2) (27,000), and gamma(3) (25,000). The combined molecular weight of these polypetides (373,000) is beyond the coding capacity of the virus genome. Purified IPNV contained polypeptides alpha, beta(3), gamma(1), and gamma(1A). Pulse-chase experiments and tryptic peptide map comparisons revealed that only four of the eight intracellular proteins were primary gene products, namely, alpha, beta(1), gamma(1), and beta(2), with a combined molecular weight of 205,000. Of these primary gene products only the alpha polypeptide was found to be stable, whereas the other three underwent intracellular proteolytic cleavage during virus morphogenesis. Polypeptide beta(1) was cleaved to generate beta(2) and beta(3); gamma(1) was trimmed to produce gamma(1A), and the only nonstructural primary gene product, gamma(2), was found to be a precursor of gamma(3). These results suggest that IPNV possesses a unique mechanism to synthesize three size classes of proteins using mRNA transcripts from two high-molecular-weight double-stranded RNA genome segments.

Animals↗