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Biomedical subjects

H Grant

Publications and source records attributed to H Grant.

At least 19 recordsLinked to original sources
PubMed1995

The influence of medium composition on the maintenance of cytochrome P-450, glutathione content and urea synthesis: a comparison of rat and sheep primary hepatocyte cultures.

Rat and sheep primary hepatocytes have been cultured in four different medium formulations: Williams' E, Chee's, Medium 199 and Modified Earle's. The total cytochrome P450 content, intracellular concentration of reduced glutathione, rate of urea synthesis and total protein content of cultures of cells from both species in each medium have been determined. Modified Earle's and Chee's medium proved to be the most favourable formulations for the culture of rat hepatocytes. After 48 h, cells cultured in Modified Earle's had significantly more cytochrome P450 and a significantly greater rate of urea synthesis than cells in any other medium. After 6 days in culture the difference in cytochrome P450 levels between rat hepatocytes in Chee's medium and those in Modified Earle's medium was abrogated. The difference in the rate of urea synthesis between rat hepatocytes cultured in each of these two media was shown to be more dependent on the medium in which the cells were maintained during the period of urea synthesis measurement than on the medium in which the cells had been previously cultured. Sheep hepatocytes cultured in Chee's medium ruptured and died within 24 h. Apart from this, sheep cells were less sensitive to changes in medium formulation than were rat hepatocytes. The initial plating efficiency was lower in sheep cells. Total cytochrome P450 content was the most discriminatory of the four parameters for evaluating the status of rat hepatocyte cultures. However, urea synthesis may be the most useful parameter for assessment of hepatocyte function in hybrid liver devices such as bioartificial liver support systems where access to the cells during operation of the device is restricted.

Ammonia↗
PubMed1995

A confidential comparative audit of stapedectomies: results of the Royal College of Surgeons of England Comparative Audit of ENT surgery 1994.

This paper presents the results of a national confidential comparative audit of stapedectomy: 185 operations by 28 consultants over a two-year period were retrospectively analysed. This included 10 revision procedures. Small fenestra stapedectomies accounted for 63 per cent of the total. Thirty-nine per cent of consultants operated on the second ear. Of the 168 stapedectomies in which the hearing change was known at six months, 87 per cent achieved improved hearing, eight per cent had no change and five per cent were worse. The overall complication rate was 30 per cent with a 'dead ear' rate of two per cent.

Bone Conduction↗
PubMed1995

Mastoidectomy audit: results of the Royal College of surgeons of England comparative audit of ENT surgery.

This paper presents the results of a national comparative audit of mastoid surgery, retrospectively analysing 611 operations by 55 consultants. Confidentiality for both patient and surgeon was assured. For cholesteatoma 80% of mastoidectomies performed were open cavity procedures and for other middle ear disease 58% used an intact canal wall technique. Thirty-two surgeons used only an open cavity mastoidectomy for cholesteatoma during the period of the audit. There was a statistically significantly greater number of wet ears with open cavities than with closed cavities, but the frequency of the operator did not correlate with the dry ear rate. Ten serious complications (facial palsy and dead ear) were recorded. All occurred in open cavity mastoidectomies. The post-operative hearing status was unknown in 40% of patients.

Cholesteatoma↗
PubMed1994

Yersinia pseudotuberculosis affecting the appendix.

Yersinia pseudotuberculosis is an uncommon cause of abdominal pain. It has a much lower incidence than Yersinia enterocolitica, and most reports have emanated from Europe or North America. This report is about a patient with Yersiniosis affecting the appendix alone, in contrast to the usual picture of mesenteric adenitis or septicemia associated with this organism.

Appendix↗
PubMed1994

Potential danger of 'trial of life' approach to congenital diaphragmatic hernia.

This is the report of a newborn girl who was treated by "trial of life" before surgical repair of her left-sided diaphragmatic hernia. Surgery was performed 60 hours after birth, at which time she was found to have an organo-axial volvulus of the stomach. Her postoperative course was complicated by a jejunal perforation on the fourth postoperative day, necessitating another laparotomy.

Combined Modality Therapy↗
PubMed1994

Microvascular free flaps in head and neck surgery.

This study is a retrospective review of 60 patients who had microvascular free flap reconstructions in the head and neck region. They were all performed over a 10-year period by a single surgeon. The series includes a wide range of flap types and analyses pre-operative risk factors for flap failure as well as complications and outcome. Smoking and advanced age did not appear to prejudice flap survival but peripheral vascular disease, cardiac disease and alcohol withdrawal were found to increase the likelihood of flap failure. The most frequent complications encountered were thrombosis of one of the anastomosis and haematoma. The most successful flap in terms of survival and function was the fasciocutaneous radial forearm flap. The literature is reviewed in relation to the general principles of microvascular free flap surgery and the results of this series are placed in context.

Adolescent↗
PubMed1994

Expression of liver functions in immortalised rat hepatocyte cell lines.

The differentiated hepatic function of two rat liver cell lines, P9 and SV40RH1, immortalised by transfection with SV40 DNA has been investigated in terms of the glutathione synthesis, and the activities of gamma-glutamyltransferase, glutathione-S-transferase and UDP-glucuronosyltransferase. SV40RH1 is a highly differentiated cell line at early passage, but the expression of some aspects of its differentiated phenotype is unstable and some functions are lost by passage 12-13. P9 is a less-well differentiated cell line, with relatively stable expression of functions between passages 4 and 13. In terms of differentiated function both cell lines represent a marked improvement over primary cultures of rat hepatocytes which de-differentiate rapidly within 24-48 h in culture. This retention of liver function in proliferating cell lines offers the opportunity to use such cells in in vitro toxicological studies.

Animals↗
PubMed1989

Osteoma of the incus.

Osteomas of the temporal bone are rare. Osteomas of the middle ear have been reported but none involving an ossicle. We describe a case of a 28-year-old man who had a conductive hearing loss caused by an osteoma of the incus.

Adult↗
PubMed1983

The effect of opioid drugs on the release of dopamine and 5-hydroxytryptamine from rat striatum following activation of nicotinic-cholinergic receptors.

The effect of (Met5)enkephalin, (D-Ala2,D-Met5)enkephalin, (Leu5)enkephalin, (D-Ala2,D-Met5)enkephalin and morphine on the release of [3H]dopamine, endogenous dopamine and [3H]5-hydroxytryptamine produced by the nicotinic-cholinergic agonist, dimethylphenyl piperazinium iodide (DMPP), was examined in rat striatal slices. The DMPP-induced release of [3H]dopamine and endogenous dopamine was reduced by the presence of (Met5)enkephalin, (D-Ala2,D-Met5)enkephalin (1-10 microM) or morphine (10 microM) but not by (Leu5)enkephalin or (D-Ala2,D-Leu5)enkephalin. The DMPP-induced release of [3H]5-hydroxytryptamine was reduced by (Leu5)enkephalin, (D-Ala2,D-Leu5)enkephalin, (Met5)enkephalin, (D-Ala2,D-Leu5)enkephalin (1-10 microM), and morphine (10 microM). All three opioids failed to alter the release of [3H]dopamine induced by field stimulation or potassium depolarization (30 microM). The inhibitory effects of opioid peptides and morphine demonstrated in the present study appear to be due to an initial interaction with nicotinic-cholinergic receptors in the striatum.

Animals↗
PubMed1983

Release of dopamine and 5-hydroxytryptamine from rat striatal slices following activation of nicotinic cholinergic receptors.

1. The administration of the nicotinic cholinergic agonists dimethylphenylpiperazinium iodide (DMPP) or nicotine caused a concentration dependent release of [3H] dopamine, [3H]5-hydroxytryptamine as well as endogenous dopamine and 5-hydroxytryptamine from superfused slices of rat striatum. 2. Release of both labelled and non-labelled transmitter was antagonized by the nicotinic antagonist, hexamethonium but not the muscarinic antagonist, atropine. 3. The present study provides additional evidence that nicotinic-cholinergic receptors are present in the mammalian central nervous system. 4. Activation of these nicotinic-cholinergic receptors in the striatum results in the release of both dopamine and 5-hydroxytryptamine.

Animals↗