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Biomedical subjects

G Spence

Publications and source records attributed to G Spence.

8 recordsLinked to original sources
PubMed2006

Differentiation of mononuclear precursors into osteoclasts on the surface of Si-substituted hydroxyapatite.

In healthy bone, resorption and synthesis are in perfect coordination. In previous studies we demonstrated that the incorporation of silicon into the hydroxyapatite (HA) lattice enhances the proliferation and differentiation of human osteoblasts. Therefore, the aim of this study was to demonstrate the effect of silicon-substituted HA (0.8 and 1.5 wt % Si-HA) on the differentiation of mononuclear cells into osteoclasts, using two different starting cultures, peripheral blood mononuclear cells (PBMC) and monocytes expressing the CD14 antigen (CD14+). Through this study, it was possible to demonstrate that Si-HA allows the differentiation of mononuclear cells into mature osteoclasts, independent of the starting culture, PBMC or CD14+. Most of the cells on the surface of the materials expressed osteoclastic markers: actin rings, several nuclei, positivity for tartrate-resistant acid phosphatase (TRAP), and vitronectin receptor. In the presence of osteoclasts, a higher release of calcium and phosphate into the medium from the 1.5 wt % Si-HA substrate was detected when compared to the HA substrate; therefore, these results indicate higher osteoclastic resorptive activity on the 1.5 wt % Si-HA surface. Si-HA can be resorbed by cellular mechanisms and have a stimulatory effect on osteoclasts, although the underlying mechanism is still poorly understood.

Cell Differentiation↗
PubMed2001

Diagnosing slipped upper femoral epiphysis.

The key to diagnosing slipped upper femoral epiphysis is a high index of suspicion. This article summarizes the important clinical features of the disorder and points out the pitfalls in diagnosis.

Adolescent↗
PubMed2000

Gastrointestinal infections presenting in general practice in Scotland.

OBJECTIVES: To determine the incidence of gastrointestinal infections (GII) presenting to general practitioners (GPs) in Scotland, To record the demographic and clinical characteristics of persons presenting with GII, To determine the proportion and characteristics of GII investigated in the laboratory, To report on the microbiological aetiology of the GII. DESIGN: Descriptive epidemiological study. SETTING: Twenty three general practices in Scotland serving a total practice population of 152,471. SUBJECTS: Patients consulting their GPs for a 'gastrointestinal infection' which met the study case definition. RESULTS: These are presented for the 3872 patient consultations for GII between April 1996 and December 31st 1997 which met the survey case definition. The crude annual rate of new consultations recorded was 1.7 per 100 person years. The crude monthly consultation rate for new cases ranged between 11 and 18 per 10,000 patients. GPs notified 9% of the cases as 'food poisoning'. A request for microbiological testing of samples at the local laboratory for clinical reasons was documented for 34% of cases with diarrhoea. The study laboratory received faecal samples by post from 66% of these cases. About one in five of the samples tested revealed evidence of infection with a common gastrointestinal pathogen. The pathogens most frequently reported were Campylobacter sp and Salmonella sp. CONCLUSION: The incidence of consultations for GII in Scotland is similar to that recorded in a recent survey in England. The very low notification rate by GPs means that statutory notification by telephone or post is a poor basis for early warning of outbreaks. It is recommended that a pilot study of electronic notification using the NHS net is set up.

Adolescent↗
PubMed1997

Impaired delivery of hemodialysis prescriptions: an analysis of causes and an approach to evaluation.

Serial kinetic modeling is commonly used in hemodialysis to assess the adequacy of dialysis. A variety of problems lead to declining Kt/V in previously stable patients. These include noncompliance, vascular access recirculation, and dialyzer dysfunction. The purpose of this study was to find the relative frequencies of these problems in a group of patients undergoing routine hemodialysis. Simultaneous urea kinetic modeling and access recirculation were tested during 3 consecutive months. The baseline Kt/V was defined as the average of each patient's Kt/V values obtained during the previous 4 mo. A clinically important fall in Kt/V was defined as a decline of > or =0.2 if the baseline Kt/V was > or =1.2, or a decline of > or =0.1 if the baseline Kt/V was <1.2. Ninety-three of 375 (25%) sessions met the criteria for a significant decline in urea kinetic modeling. The baseline Kt/V in this group was 1.33 +/- 0.20 (mean +/- SEM) and declined to 1.02 +/- 0.18 in the abnormal month (P < 0.05). In 42% of instances with a decline of Kt/V, reduced blood processing due to a lower blood flow or shorter time than prescribed was responsible. Recirculation of >12% was found in 25% of sessions with a decrease in Kt/V. These patients most often had access dysfunction or reversed needles. The remaining one-third of patients with decreases in Kt/V had no problem identified, and subsequent monthly kinetic modeling results returned to baseline. These results suggest that analysis of falling urea kinetic modeling results should include a careful review of the dialysis record for reductions in prescribed time or blood flow rates followed by vascular access testing. If these evaluations are unrevealing, urea kinetic modeling results usually return to baseline in the next month.

Adult↗
PubMed1990

A review of animal bites in Delaware--1989 to 1990.

Rabies, a disease associated with aggression in animals, has been endemic in terrestrial wildlife in New Castle County, Delaware, since November 1987. There have been four documented deaths in humans in Delaware since 1919, although the last case originated in Maryland and was hospitalized in Delaware in 1975. Because of the potential association of pet animals with wild animals and the subsequent contact with humans, emphasis is placed on preventive medicine (vaccinations) and prevention of animal bites. People are bitten more often by dogs than any other domestic animal, causing injury, pain and sometimes death.

Animals↗