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Biomedical subjects

C Gray

Publications and source records attributed to C Gray.

At least 91 records · Page 5Linked to original sources
PubMed1998

Advanced bone formation in grooves in vitro is not restricted to calcified biological materials.

The aim of this in vitro study was to investigate whether the phenomenon of advanced bone formation in grooves (Bone 18, 115, 1995) is restricted to calcified biological materials. Osteoblasts were released from neonatal rat calvaria by enzyme digestion and cultured in EMEM and 10% FCS. At confluence, they were seeded on to dentine, bone, plastic, titanium, or silicon, which had been grooved using a water-cooled, diamond-edged, slow-speed or high-speed circular saw or reciprocating wire saw, or a rotating dental burr. Cultures were continued for 14-21 days, with a few extended for up to 7 weeks. Osteoblasts were also cultured on grooved dentine and plastic with or without added Stanozolol for 18 days, and bone formation assayed by measuring the total length of bone formed in the grooves in each specimen. Bone formation always occurred first within the grooves and was appositional. It formed on both calcified biological and nonbiological substrates, but developed consistently earlier on the biological substrates, and conformed to both the main grooves and the secondary finer grooving within them. Surface features at scales ranging from the millimeter to nanometer therefore influence the development of bone in vitro and possibly in vivo. The described site-induced bone formation system is valuable as an in vitro assay for biomaterial and pharmaceutical research.

Animals↗
PubMed1998

Postnatal development of Leydig cells in the opossum (Monodelphis domestica): an immunocytochemical and endocrinological study.

This study involved characterization of Leydig cells of the opossum Monodelphis domestica, functionally by immunocytochemical identification of the enzyme 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) and by measurement of testosterone levels using RIA. Immunostaining for 3 beta-HSD was first detected in a few Leydig cells on Day 16, was increased by Day 24, reached a peak at 4 mo, and was present even in senescent (3 yr) animals. Plasma testosterone was first measurable (0.35 nM) at prepuberty (3.5 mo). Prior to that, plasma testosterone concentrations were uniformly below the level of detection (< 0.3 nM) in both sexes from Day 5 to 2.5 mo. By 4 mo (puberty), plasma testosterone levels in males had risen significantly to 1.53 +/- 0.35 nM, continuing to increase to 1.79 +/- 0.4 nM at 6 mo and peaking at 2.71 +/- 0.29 nM in the adult (1-2 yr). Ovarian testosterone concentrations were consistently lower than those in the testis, as were those of adrenals of both sexes. Thus the testis would appear to be the major source of androgen production throughout life in this species. Our immunocytochemical study suggests that in Monodelphis, puberty is reached at 4 mo, and this was further supported by a rise in circulating testosterone levels at this time.

3-Hydroxysteroid Dehydrogenases↗
PubMed1998

Service-level agreements at the Huddersfield NHS Trust.

Service-level agreements (SLAs) have been claimed to be an excellent vehicle for organisational improvement where there is a substantial degree of departmental autonomy. Such a situation is likely to exist in NHS trust hospitals because of the differentiated nature of the work performed by each department, with varying degrees of specialisation and professionalism, access to patients, use of technology and differing cost bases but also an interdependence of the direct services to the support services. It is proposed that SLAs can be used to promote improved integration between departments, quality assurance and provide a framework for cost transfer charging. The article describes and analyses SLAs from an overview of the idea to the particular implementation to date at the Huddersfield NHS Trust. SLAs have been negotiated between the Directorate of Clinical Support and its customers, and these are supported by computerised measurement and reporting tools.

Ancillary Services, Hospital↗
PubMed1998

Emmetropisation, axial length, and corneal topography in teenagers with Down's syndrome.

AIM: To study the refractive status and corneal topography in Down's syndrome. METHOD: A matched cohort subgroup of 50 individuals with Down's syndrome in the Manchester area aged 15-22 years was studied by refraction, corneal topography, A-scan biometry, slit lamp examination, and orthoptic examination. RESULTS: (1) A linear relation was found between axial length and spherical equivalent refraction. There was no statistical relation between keratometry and the axial length. (2) 80% of the group had a hyperopic refraction (mean +2.46 D, range +0.5 to +7.5 D); 18% were myopic (mean -2.75 D, range -0.5 to -8.0 D); and 2% were emmetropic (within plus or minus 0.5 D of zero). The overall mean spherical equivalent refraction was +1.43 (SD 2.86) D. 63% of eyes could see 6/12 or better and 66% of the individuals had a binocular vision of 6/12 or better. (3) Corneal topography was generally of a regular "bow tie" pattern, but there was a high incidence of oblique cylinders. Mean cylinder strength was 1.14 (1.15) D. (4) The prevalence of overt keratoconus was 2%. 6% had corneal topography with inferior steepening which may be a preclinical keratoconic process. CONCLUSIONS: In this cohort of late teenagers with Down's syndrome, emmetropisation has failed to occur in most individuals. In a similar aged group of non-disabled individuals one would expect about 83% emmetropic (plus or minus 0.25 D), 13% myopic, and 4% hyperopic. The wide spread of oblique cylinders and the small proportion of with the rule astigmatism is probably related to this failure of emmetropisation. The prevalence of 2% keratoconus in Down's syndrome compares with that found by other authors of between 5.5 and 15%. The 6% with inferior steepening on topography will be followed up over the next few years to see if there is any development of clinical keratoconus. Hence we will see if corneal topography is useful as a screening tool for preclinical keratoconus in this high risk group.

Adolescent↗
PubMed1998

An audit of clinical placements.

Clinical teaching of students is a requirement of the majority of practicing therapists in the UK and yet there is little guidance as to the nature of the placement which needs to be offered. As models of service delivery change, placements must change to prepare the student for working life whilst also meeting the need for solid foundation experiences. The audit reported here examined current placements including the physical setting, level of supervision provided and the responsibilities described by the professional body (Royal College of Speech and Language Therapists 1996) The results are discussed in the context of their implications for the educational establishment and the clinical teaching setting.

Humans↗
PubMed1998

Frontal lobe functioning in man: the riddle revisited.

Forty-eight patients, each with a single frontal lobe lesion, were tested with a battery of 10 of the most widely used neuropsychological tests, comprising five traditional "frontal" tests and five others, for which that claim is not generally made. All correlations among the tests in the group were positive and significant. Moreover, the average correlation between each frontal test and the other tests in the frontal group was found to be higher than the average correlation of the same frontal test with the tests in the other group. A factor analysis of the scores on the five frontal tests yielded a single factor accounting for 53% of the variance. A factor analysis on the entire battery of tests (frontal plus nonfrontal) also yielded a strong general factor; although this accounted for a smaller portion (43%) of the shared variance, and one test (Verbal Span) failed to show a substantial loading on the factor. Neither the results of the present study nor the findings of other researchers argue for the abandonment of the concept of "executive" functioning, mediated by the functioning of the frontal lobes, in favor of a variant of fractionation.

Journal Article↗
PubMed1998

Disposition of cyproheptadine in cats after intravenous or oral administration of a single dose.

OBJECTIVE: To determine disposition of cyproheptadine hydrochloride in cats after intravenous or oral administration of a single dose. ANIMALS: 6 healthy cats. PROCEDURE: A randomized crossover design was used, and each cat was studied after intravenous (2 mg) and oral (8 mg) administration of cyproheptadine. Blood samples were collected at fixed time intervals after drug administration, and serum cyproheptadine concentration was determined by means of polarized immunofluorescence. RESULTS: Mean (+/- SD) residence time was significantly longer after oral (823 +/- 191 minutes) than after intravenous (339 +/- 217 minutes) administration, but no significant differences were detected between other pharmacokinetic parameters after oral and intravenous administration. Mean +/- SD oral bioavailability was 1.01 +/- 0.36. Mean elimination half-life after oral administration was 12.8 +/- 9.9 hours. Peak extrapolated cyproheptadine concentration was 669 +/- 206 ng/ml. Only 1 cat developed adverse effects (transient vocalization). CONCLUSIONS: Cyproheptadine appeared to be well tolerated in cats and had high bioavailability after oral administration. The mean elimination half-life of 12 hours indicated that approximately 2.5 days must elapse to achieve steady-state concentrations of cyproheptadine after oral administration of multiple doses. A 12-hour dosing interval is acceptable, but an 8-hour interval may be indicated for some cats. CLINICAL RELEVANCE: On the basis of pharmacokinetic parameters determined in this study, the oral form of cyproheptadine appears to be suitable for use in clinical trials to treat anorexia in cats. Its half-life is compatible with once or twice daily dosing.

Administration, Oral↗
PubMed1998

Assessing the accuracy of partial weight-bearing instruction.

A force-monitoring platform was used to ascertain accuracy in following instructions concerning partial weight bearing. Three groups of healthy volunteers were instructed to bear 60 pounds of weight on a foot in one of three ways: on a bathroom scale, against a therapist's hand, or on a force-monitoring platform. The accuracy of each group, tested against platform measures, revealed significantly greater accuracy in the group instructed on the force-monitoring platform.

Adolescent↗
PubMed1997

Service-level agreements. Trading places.

Internal trading or service-level agreements can help trusts manage the interface between hospital consultants and support services. Previous attempts at introducing SLAs had increased the administrative burden on support departments without changing consultants' behaviour or improving budgetary control. Problems were resolved by simplifying and improving measuring and reporting systems to produce credible, user-friendly information that facilitates meaningful debate between clinical managers and support services.

Ancillary Services, Hospital↗
PubMed1997

1997 up and comers.

Leadership is both singular and diverse, subtle and bold. It moves others, transcends the obvious and stretches the boundaries of achievement. And it's always passionate about what it does. Being a leader in today's complex, evolving healthcare industry is an especially challenging task. Modern Healthcare salutes this year's "Up & Comers," 13 young executives, all 40 or under, who already have made their marks and will help shape the future of healthcare.

Administrative Personnel↗
PubMed1997

With a system in turmoil, will there be enough blood?

In a short time Canadians won't be able to recognize their blood-collection system. With the Red Cross getting out of the blood business and the government and business moving in, what will the changes mean for Canadians and their physicians?

Blood Banks↗
PubMed1997

The recognition of haemoglobin by antibodies raised for the immunoassay of beta-amyloid.

Canine and porcine cerebrospinal fluid (CSF) were fractionated by size exclusion chromatography and analysed by a luminescence enzyme linked immunosorbent assay (ELISA) configured to detect beta-amyloid. A peak of activity was observed in the CSF consistent with the molecular weight of beta-amyloid. When CSF contaminated with blood was analysed an additional peak of immunoreactivity at a higher molecular weight was observed. The peak of activity was found to be derived from cross-reactivity of the immunoglobulins employed in the ELISA with haemoglobin. These findings are discussed with reference to primary and structural sequence homology between beta-amyloid and haemoglobin from a number of species, the known properties of beta-amyloid and recent clinical reports.

Amyloid beta-Peptides↗