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Biomedical subjects

D J Rowe

Publications and source records attributed to D J Rowe.

At least 19 recordsLinked to original sources
PubMed1996

Osteoclast inhibition by factors from cells associated with regenerative tissue.

Guided tissue regeneration (GTR) uses expanded polytetrafluoroethylene (ePTFE) membranes to favor the repopulation of the healing wound with cells with bone regenerative potential. As bone remodeling is a tightly coupled process, inhibition of osteoclast-mediated bone resorption may be critical to regeneration. Thus, this study was undertaken to determine whether cells associated with regenerative tissue can inhibit osteoclast differentiation and activity and to begin characterizing and identifying the factor(s) mediating the observed effects. Conditioned media were harvested from human periodontal cell lines established in culture: cells adherent to ePTFE membranes, recovered from patients after GTR; cells adherent to ePTFE augmentation membranes, recovered from edentulous ridge augmentation procedures; and periodontal ligament cells from periodontally healthy bicuspids. Conditioned medium from each of these regenerative cell lines reduced the number of tartrate-resistant acid phosphatase-positive osteoclast-like cells formed from hemopoietic precursors in mouse bone marrow cultures. Also, both the total resorbed surface area and number of resorption pits formed by these cells on calcium phosphate ceramic films were reduced. The factor in the conditioned medium which inhibited osteoclast differentiation was soluble, heat labile, and resided in the lower molecular weight (< 30 kDa) fraction, the same fraction which would contain cytokines. Western blot analysis of the conditioned medium detected a band at the molecular weight of interferon gamma (IFN-gamma), using a polyclonal rabbit anti-human IFN-gamma. Thus, the factor in the conditioned medium with inhibitory activity may have identity with IFN-gamma or one of the other anti-inflammatory cytokines.

Animals↗
PubMed1994

Diagnostic strategy to monitor diabetic nephropathy.

Although much evidence supports the theory that microalbuminuria is predictive of the development of clinical diabetic nephropathy, other experimental data fail to support this conclusion. It remains unclear whether random urine samples offer as much clinical information as timed overnight or 24 hour samples. Clinical decisions as to treatment based on improved glycemic control or enhanced antihypertensive treatment should be structured to the urinary albumin concentration. Tubular dysfunction is common in diabetes, but is clinical relevance remains unclear.

Albuminuria↗
PubMed1992

Speech recognition and the clinical microbiology laboratory.

Keyboard entry of large amounts of diagnostic data is a laborious task. Any transcription errors that occur may pass undetected by 'non-technical staff' employed to input these data. The object of this project was to design a system, based on a Marconi 'Macrospeak' Speech Recogniser, for 'on line' laboratory entry of data generated from the microbiological examination of specimens of urine. Six parameters considered important to the success of the system were assessed: accuracy, speech recognition, reproducibility, speed, user friendliness, and cost effectiveness. The system performed well under the test conditions examined. 'On line' hands free entry of diagnostic data, using speech recognition, may be a practical alternative to more conventional means of data entry.

Clinical Laboratory Information Systems↗
PubMed1991

Biphasic effect of calcitonin on tartrate-resistant acid phosphatase activity in isolated rat osteoclasts.

Tartrate-resistant acid phosphatase (TRAP) has been implicated as being involved in osteoclastic bone resorption, and calcitonin (CT) is known to inhibit the resorptive process. This study investigates the kinetics of CT action on TRAP activity in isolated rat osteoclasts using both biochemical and quantitative cytochemical methods. The latter technique has been developed to detect very small changes in intracellular TRAP activity at the single-cell level. The biochemical study showed that 10(-9) M salmon CT (sCT) decreased TRAP activity in medium throughout the experimental period; TRAP activity in the cells was increased during the first 2 h but subsequently declined and was decreased to a significant level at 6 h. TRAP activity in sCT-treated osteoclasts measured by the cytochemical method showed significant increases within the first hour. This response was dose dependent between 10(-16) and 10(-11) M sCT with EC50 at 8 X 10(-14) M. After 1 h, the initial increase in intracellular TRAP activity in CT-treated osteoclasts was followed by a decline to below control levels, reaching statistical significance at 9 h. Treatment with forskolin (10(-5) M) showed a similar trend, suggesting that this response is mediated by cyclic AMP-regulated phosphorylation events. From these results, we conclude that CT has two actions on TRAP in isolated rat osteoclasts: the first to inhibit its release, the second to inhibit its synthesis and/or increase its degradation.

Acid Phosphatase↗
PubMed1991

A carboxyl-terminal peptide from the parathyroid hormone-related protein inhibits bone resorption by osteoclasts.

PTH-related protein (PTHrP) interacts, via its amino-terminal 34 residues, with PTH receptors on osteoblasts to stimulate osteoclastic bone resorption indirectly. We now report that mature hPTHrP-(1-141) (EC50, approximately 10(-11) M) and a carboxyl-terminal fragment, PTHrP-(107-139) (EC50, approximately 10(-15) M), are potent inhibitors of resorption in an isolated rat osteoclast bone resorption assay, whereas hPTHrP-(1-108) and hPTHrP-(1-34) are inactive in this respect. PTHrP-(107-139) also inhibits resorption in a rat long bone organ culture system and reduces osteoclast spreading. PTHrP-(107-139) does not act on osteoclasts via a cAMP signal transduction mechanism, but its effects may be mediated by protein kinase-C. This previously unrecognized action of PTHrP, to inhibit osteoclastic bone resorption directly, indicates that PTHrP may be a precursor of multiple biologically active peptides with differing physiological functions.

Amino Acid Sequence↗
PubMed1989

Neonatal renal function assessment.

Urine samples from neonates admitted to a special care baby unit were analysed to establish ranges for urinary retinol binding protein, albumin, and total protein concentrations in healthy term and preterm infants and to investigate changes seen in disease states. Urinary excretion of retinol binding protein was greater in preterm infants and was increased in sick infants. This was greater than would be predicted from changes in creatinine excretion with gestational or postconceptional age. Urinary retinol binding protein appeared more sensitive to illness than did urinary albumin or total protein.

Albuminuria↗
PubMed1989

Low-molecular-weight proteinuria in insulin-dependent diabetes mellitus: a study of the urinary excretion of beta 2-microglobulin and retinol-binding protein in alkalinized patients with and without microalbuminuria.

The urinary excretion of two low-molecular-weight proteins (beta 2-microglobulin and retinol-binding protein) was measured in 12 insulin-dependent diabetic patients with persistent microalbuminuria and an equal number with normal albumin excretion; reference ranges for the excretion of beta 2-microglobulin (beta 2M) and retinol-binding protein (RBP) were also obtained in 40 non-diabetic subjects. To ensure the stability of beta 2M in urine a urinary pH greater than or equal to 7 was achieved by giving oral sodium bicarbonate. beta 2M and RBP excretion was significantly higher in the diabetics than in the controls (p less than 0.01), but no higher in microalbuminuric than non-albuminuric diabetics. In the diabetics as a group a significant correlation was found between the excretion of beta 2M and RBP (r = 0.53, p less than 0.01), but more patients had an abnormal excretion of beta 2M than RBP (p less than 0.001). No significant correlation was found between the urinary excretion of either low-molecular-weight protein and duration of diabetes, insulin dose, HbA1, urinary glucose excretion or systemic blood pressure. Measured under appropriate alkaline conditions beta 2M appears to be more sensitive than RBP in detecting an abnormality of the renal proximal tubule which may be an early feature of diabetic renal involvement not characterized by microalbuminuria; microalbuminuria may have glomerular and tubular components.

Adolescent↗
PubMed1988

Reference values for 75 g oral glucose tolerance test in pregnancy.

A 75 g oral glucose tolerance test was performed in 212 pregnant women with no predisposing factors suggesting glucose intolerance to establish the normal pattern of glucose metabolism in pregnancy. Reference values for the test were established for the middle of pregnancy (14-20 weeks, n = 43) and late pregnancy (28-37 weeks, n = 168). One woman was excluded because she had diabetes that required treatment with insulin. There were statistically significant differences between the two groups for samples taken both one and two hours after the glucose load. Reference ranges for the interpretation of the glucose tolerance test in pregnancy should therefore take account of the period of gestation. Arbitrary upper limits of normal (represented by the 97.5 centile) two hours after a 75 g oral glucose load are proposed at 7.5 and 9.6 mmol/l for the second and third trimesters, respectively.

Blood Glucose↗
PubMed1988

A new antigen identified by the monoclonal antibody UCHB 1 delivers a costimulatory signal to a subset of human B cells.

A novel anti-B cell monoclonal antibody UCHB1 is described which detects an antigen present on a selected subpopulation of both normal and leukemic B cells. Approximately 20% of normal tonsil and peripheral blood (PB) B cells are UCHB 1+ and the majority of B cells from all cases of prolymphocytic leukemia (PLL) tested, together with a low, variable percentage of PB B cells from non-Hodgkin's lymphoma patients with centroblastic centrocytic leukemia also express this antigen. Chronic lymphocytic leukemia and hairy cell leukemia B cells, pre-B acute lymphoblastic leukemia and Epstein-Barr virus transformed cell lines all lack UCHB 1 positivity as do all non-B lineage leukocytes and cell lines so far tested. In tonsil sections UCHB 1 staining is almost completely confined to surface IgM+ mantle zone lymphocytes and follicular dendritic cells, but not B cells, within the germinal centers. UCHB 1 can induce a rise in the level of intracellular free calcium ([Ca2+]i) in PLL B cells and low concentrations of monoclonal antibody can result in the entry of these cells into cell cycle in the absence of additional factors. The proliferative effect of UCHB 1 is greatly enhanced in the presence of Staphylococcus aureus Cowan and, to a lesser extent, phorbol ester. A similar costimulatory effect is exerted on a proportion of normal tonsil B cells although here, despite inducing a rise in [Ca2+]i, UCHB 1 alone does not cause cells to proliferate. UCHB 1 may well prove to be a useful antibody both to distinguish between different B cell leukemias and to study the phenotype and function of leukemic and normal B cell subpopulations.

Animals↗
PubMed1988

Uptake of a fluorinated bisphosphonate by cultured bones.

The uptake of bisphosphonates into bone was studied using 19-day-old fetal rat bones cultured with a new fluorinated bisphosphonate, difluoromethylidene bisphosphonate (F2MBP). F2MBP uptake was assessed by determining the weight percent of fluoride using electron probe microanalysis. By 30 min the weight percent of fluoride was significantly greater in the F2MBP-treated bones than in controls and continually increased throughout the duration of the experiment to reach a fluoride concentration 6-fold greater than controls after 120 h of incubation. When the peripheral cortical bone was analyzed separately from the interior trabecular bone in the F2MBP-treated bones, the fluoride concentration in the periphery increased until 24 h and then remained somewhat constant, while the interior, which is more actively remodeling, showed a continual increase. The uptake of F2MBP during the 1 to 6 h time intervals demonstrated no differences between vital and devitalized bone and, thus, is not cell-mediated. Because analysis of free fluoride in F2MBP media incubated with bones showed that the concentration of fluoride was less than 1% of the total amount of fluoride, the fluoride detected by the probe was most likely that of the intact molecule and not free fluoride. The rapid uptake of the F2MBP molecule was supported by assessing the effects of short-term F2MBP treatment on subsequent bone resorption, as determined by the release of 45Ca from prelabeled bones. Bones treated with F2MBP for only 5 min exhibited reductions in the percentage of 45Ca released during the remainder of the 120 h incubation period similar to that when F2MBP was continuously in the medium.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

The clinical use and measurement of theophylline.

This report reviews the clinical use, metabolism and toxicity of theophylline (Section 1). Current chromatographic and immunoassay methods for theophylline measurement are discussed and practical methods using high-performance liquid chromatography are described (Section 2). Results from the UK National scheme for theophylline quality control and from an experiment to investigate the degree of interference by 1,7-dimethylxanthine in routine assays for theophylline are discussed in Section 3.

Humans↗
PubMed1987

Retinol binding protein as a small molecular weight marker of renal tubular function in diabetes mellitus.

A radioimmunoassay has been developed for the measurement in urine of retinol-binding protein (alpha 2-microglobulin) and used as an index of renal tubular function in adult Type 1 (insulin-dependent) diabetics and to define reference ranges in non-diabetic controls. There was a significantly greater excretion (P less than 0.001) of retinol-binding protein in the diabetic group compared to the controls in both overnight and daytime samples. There was a weak positive correlation with albumin excretion (r = 0.33; P less than 0.01) but no correlation with HbA1, duration of diabetes or arterial blood pressure. The results indicate that retinol-binding protein excretion may be increased in diabetic subjects without increased albumin excretion. The possibility therefore exists that renal tubular damage may occur early in diabetic nephropathy without apparent glomerular dysfunction.

Adolescent↗