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Biomedical subjects

J Graham

Publications and source records attributed to J Graham.

At least 181 records · Page 10Linked to original sources

Cochlear implants in children: physiological considerations.

Cochlear implants now play a standard role in the management of adults with acquired profound sensorineural deafness. Their role in children is more controversial. However, as demonstrated by a 1979 report on childhood deafness in the European Communities, there is no reason for complacency in the present management of profoundly deaf children. Transtympanic electrocochleography has been used as a method of estimating neural survival in deafened adults being assessed for the U.C.H./R.N.I.D. single channel extracochlear implant and also in a parallel group of profoundly deaf children referred by a paediatric hearing assessment clinic. In adults the effectiveness of electrocochleography in judging neural survival was monitored by electrical stimulation of the cochlea and found to be significantly effective. This result was extrapolated to the paediatric group to estimate the proportion of congenitally deaf children who might benefit from a cochlear implant. It is suggested that in a programme designed to implant such children at 2 years of age, techniques should be chosen that neither damage the cochlea nor the middle ear sound conducting mechanism.

Adult↗

Results of treatment of non seminomatous germ cell tumours; 122 consecutive cases in the West of Scotland, 1981-1985.

Between January 1981 and December 1985, 122 patients with non-seminomatous germ cell tumours (NSGT) were seen at a regional referral centre. Of these, a total of 98 patients received chemotherapy for metastatic disease. Treatment was given within collaborative EORTC Urology group studies, all of which involved cis-platin-containing schedules. Ninety patients had tumours of testicular origin, and their 2 year actuarial survival rate is 91%; 8 had tumours of extragonadal origin and their 2 year actuarial survival is 25%. Patients with testicular tumours were subdivided by volume of metastatic disease using the recommendations of the Testicular Cancer Subgroup of the MRC Urological Cancer Working Party and survival was significantly worse in the group with very large volume metastatic disease (VLVM, 57%) compared with the groups with large volume metastases (LVM, 100%) and small volume metastases (SVM, 98%). There were 31 patients with Stage I disease at presentation; of these 6 were treated by prophylactic abdominal radiotherapy and 25 were managed by a policy of surveillance only. Seven of these Stage I patients (23%) relapsed with metastatic disease (median 8 months); all have been successfully treated with chemotherapy. These data confirm that the majority of patients now presenting with metastatic NSGCT are curable with chemotherapy, but that a small proportion with very large volume metastases or extragonadal tumours require alternative chemotherapy schedules.

Antineoplastic Combined Chemotherapy Protocols↗

The impact of preoperative skin disinfection on preventing intraoperative wound contamination.

The efficacy of total body showering and incision site scrub with disinfectant agents was evaluated in a randomized, prospective study of 575 patients undergoing selected surgical procedures. Patients who showered twice with 4% chlorhexidine gluconate had lower mean colony counts of skin bacteria at the surgical incision site in the operating room prior to the final scrub than patients who showered twice with povidone-iodine solution or medicated bar soap. Patients in the chlorhexidine group had no growth on 43% of the incision site skin cultures compared with 16% in the povidone-iodine group and 6% in the soap and water group. Patients who showered and who were scrubbed with chlorhexidine also had lower rates of intraoperative wound contamination. Bacteria were recovered from the wounds of 4% of patients using this regimen compared with 9% for patients who used povidone-iodine and 15% for patients who showered with medicated soap and water and were scrubbed with povidone-iodine. We noted no difference in surgery-specific infection rates among patients in the three treatment groups; however, our sample sizes were too small to evaluate this outcome parameter adequately. These data suggest that preoperative showering and scrubbing with chlorhexidine is an effective regimen to reduce extrinsic intraoperative contamination of the surgical wound from skin bacteria. The efficacy of this regimen to prevent postoperative wound infection needs to be evaluated in a well-designed, carefully controlled prospective trial with adequate numbers of patients to achieve statistically valid conclusions.

Baths↗

Receptor-mediated endocytosis of enterokinase by rat liver. Preliminary characterisation of low-density endosomes.

The endocytosis of enterokinase by rat hepatocytes has been studied both in a perfused liver system and in the intact, anaesthetised animal. 10 min after administration of the enzyme, only 70% of the activity was cleared by the perfused liver, whereas clearance was total in the intact animal. In both cases, about 85% of the internalised enzyme co-purified with the smooth microsomes and virtually all (more than 90%) of the catalytic activity was latent and could only be detected in the presence of detergent. After 10 min, 22.5% of the activity remained with the sinusoidal plasma membrane in the case of the perfused liver, while for the intact animal this figure was only 10%, confirming the more efficient clearance of enterokinase in the intact animal. Further subcellular fractionation showed that in the anaesthetised animal 8% of the internalised enzyme was associated with a low-density Golgi-like endosomal compartment (prepared from the mitochondrial pellet), whereas the corresponding value for the perfused liver was only 2.5%. Enterokinase specific activity was also up to 50-times greater in the low-density endosomes prepared from the intact animal. A second low-density Golgi-like compartment (purified from the smooth microsomes) also contained latent enterokinase, which together with the endosomes derived from the mitochondria accounted for 20% of the total enterokinase internalised by the liver 10 min after its administration to the intact animal. The passage of enterokinase through these two low-density compartments was shown not to be synchronous with its passage through the peripheral (sinusoidal membrane) and internal endosomes (smooth microsomes). There were qualitative differences in marker enzymes and polypeptide composition between the mitochondria and microsome-derived low-density endosomes. The sub-fractionation of low-density fractions on shallow sucrose gradients revealed a complex enzyme and polypeptide heterogeneity both between and within fractions. There was an apparent density-dependent separation of enterokinase from galactosyltransferase and the asialoglycoprotein receptor which was coincident with marked changes in the polypeptide composition of the endosomal membranes, particularly in the 30-45 kDa range.

Animals↗