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Biomedical subjects

B George

Publications and source records attributed to B George.

At least 55 records · Page 3Linked to original sources
PubMed2001

Long-term oncological results in 47 cases of jugular paraganglioma surgery with special emphasis on the facial nerve issue.

Oncological and functional results were assessed in 47 type C and/or D jugular paraganglioma operated on between 1984 and 1998 using the classical infratemporal fossa type A approach (mean follow-up = 66 months). In 24 instances, however, the facial nerve was not re-routed. Total resection was achieved in 33 cases (70 per cent). In 25 patients available for follow-up this resulted in a 92 per cent cure rate while two patients (eight per cent) developed recurrences that are being followed-up clinically and radiologically. Sub-total resection, leaving infracentimetric tumour remnants after being coagulated, was achieved in 14 cases (30 per cent). In 11 patients available for follow-up, only three cases developed tumour regrowth (27 per cent) that was controlled by salvage irradiation or surgery while in the other cases tumour remnants remained stable (73 per cent). Symptomatic post-operative lower cranial nerve impairment was observed in 23 per cent. When results were analysed depending on whether the facial nerve had been re-routed (n = 18) or not (n = 24), the incidence of facial paralysis HB grade III or more at one year was 33 per cent and eight per cent, respectively. Total resection was achieved in 56 per cent when the facial nerve was re-routed versus 75 per cent when it was not, the difference being due to a higher incidence of large tumours in the first group. The present study suggests that: 1) surgical resection of jugular paraganglioma provides overall satisfactory results, i.e. a 86 per cent rate of either cure or tumour remnant stabilization, but carries a significant risk of iatrogeny; 2) complete tumour removal should not be attempted, especially in patients over 60 years of age with no pre-operative neurological deficits, since leaving infracentimetric tumour remnants has no major detrimental effect on the final outcome; 3) facial nerve transposition carries a significant risk of cosmetic sequelae while it does not provide significant advantages in terms of tumour resection and long-term oncological control.

Adolescent↗
PubMed2001

Cost-effectiveness analysis and the consistency of decision making: evidence from pharmaceutical reimbursement in australia (1991 to 1996).

OBJECTIVE: The principle aim of this study was to generate a league table of drugs considered by the Australian Pharmaceutical Benefits Advisory Committee (PBAC) for reimbursement. The table was used to test the hypothesis that decisions made by the PBAC are consistent with the maxim of economic efficiency. In addition, we explored whether the past decisions by the PBAC revealed a threshold incremental cost-effectiveness ratio beyond which the PBAC is not prepared to recommend reimbursement of a drug. METHODS: All 355 submissions made to the PBAC between January 1991 and June 1996 were reviewed. Submissions using cost per life-year gained (26 submissions) or the cost per quality adjusted life-year (QALY) gained (9 submissions) were ranked in a league table and compared with advice given by the PBAC about that drug. The confidentiality restrictions for the submissions require that the individual drug details cannot be revealed in this article. RESULTS: There was a statistically significant difference between the cost per life-year gained for drugs that were recommended for listing and those that were not, suggesting that the PBAC has been broadly consistent with the use of economic efficiency as a criterion for decision making. We did not find an explicit threshold beyond which the PBAC was unwilling to pay for additional life years gained. However, between 1992 and 1996 the PBAC appears to have been unlikely to recommend a drug for listing if the additional cost per life-year exceeded 76 000 Australian dollars [$AU] (1998/1999 values) and was unlikely to reject a drug for which the additional cost per life-year gained was less than $AU42 000. The cost-effectiveness ratio was not the only factor determining the reimbursement decision. CONCLUSIONS: The results of this preliminary study indicate that decisions to recommend a drug for listing by the PBAC in the last few years have, by and large, been consistent with the notion of economic efficiency.

Australia↗
PubMed2001

DeLee suction. Does it have clinical significance?

OBJECTIVE: To evaluate the null hypothesis that there would be no difference in neonatal outcome in infants who underwent DeLee suction vs. those who underwent bulb suction when thick meconium was present. This difference was defined as a one-day difference in length of stay, two-point difference in the five-minute Apgar score or significant difference in blood gases. STUDY DESIGN: A power calculation based on a one-day length of stay found that 115 patients would be needed in each arm. A cohort of 115 consecutive deliveries with the presence of thick meconium was reviewed during each time period when DeLee suction was utilized and then matched with deliveries that used bulb suction. RESULTS: Two hundred thirty charts were reviewed. Length of stay, one-minute Apgar score, five-minute Apgar score, blood gases, gestational age and incidence of amnioinfusion were compared. There was no significant difference in any variable. Meconium aspiration syndrome in the period studied remained stable at < 1%. CONCLUSION: There was no significant clinical change in neonatal outcome with the abandonment of nasopharyngeal DeLee suction on the perineum when meconium was present. We recommend the use of bulb suction as routine obstetric practice even in the presence of thick meconium.

Apgar Score↗
PubMed2000

Surgical resection of jugulare foramen tumors by juxtacondylar approach without facial nerve transposition.

PRESENTATION: Jugulare foramen tumors (JFT) remain a difficult challenge especially in the forms extending extradurally and invading the petrous bone. In the standard technique, facial nerve function is placed at risks because of its transposition. We report on 31 extradural (N = 11) or intra-extra dural (N = 20) JFT resected surgically using the juxtacondylar approach alone or in combination with the infratemporal approach and without facial nerve transposition. RESULTS: The juxtacondylar approach permits the opening of the JF on its posteroinferior aspect and thus reduces the extent of petrous bone drilling. In tumors strictly located in the JF (N = 11), no petrous bone drilling is necessary and the facial nerve is never exposed. In tumors extending into the petrous bone (N = 20), the facial nerve was never transposed and moreover was kept in its bony canal in 15 cases. In only 5 cases, was the fallopian canal opened as the tumor was invading its bony wall. Similarly hearing function, when pre-operatively intact was always preserved and a better preservation of the lower cranial nerves could be achieved. Whatever the tumoral extent along the petrosal carotid artery, a radical resection could be realized in 30 cases. CONCLUSION: Therefore, we consider the juxtacondylar approach a useful adjunct to increase the possibilities of resection of JFT; it allows a better preservation of the neurovascular structures, especially the facial nerve which is kept in place and moreover kept in its bony canal when it is not invaded by the tumor.

Adolescent↗
PubMed2000

Use of OKT3 for acute myocarditis in infants and children.

Acute viral myocarditis triggers an autoimmune phenomenon that aggressive immunosuppressive therapy with monoclonal OKT3 may suppress. We treated 5 patients, aged 15 months to 16.5 years, who had acute viral myocarditis and left ventricular ejection fraction (LVEF) of 5% to 20%, with a combination immunosuppressive regimen that included OKT3, intravenous immunoglobulin, methylprednisone, cyclosporine, and azathioprine. Within 2 weeks of therapy, all patients demonstrated normalization of LVEF to 50% to 74%, and on mid-term follow-up, we have found no recurrence of heart failure or progression to dilated cardiomyopathy. In patients with severe acute myocarditis, aggressive immunosuppressive regimen based on OKT3 is safe and may inhibit or reverse the immune response, resulting in dramatic improvement in myocardial function.

Acute Disease↗
PubMed2000

Glyphosate-tolerant corn: the composition and feeding value of grain from glyphosate-tolerant corn is equivalent to that of conventional corn (Zea mays L.).

Glyphosate-tolerant (Roundup Ready) corn line GA21 has been developed by genetic modification to tolerate glyphosate, the active ingredient in Roundup herbicide. The purpose of this study was to evaluate the compositional and nutritional safety of corn line GA21 compared to that of conventional corn. Compositional analyses were conducted to measure proximate, fiber, amino acid, fatty acid, and mineral contents of grain and proximate, fiber, and mineral contents of forage collected from 16 field sites over two growing seasons. The nutritional safety of corn line GA21 was evaluated in a poultry feeding study conducted with 2-day old, rapidly growing broiler chickens, at a dietary concentration of 50-60% w/w. Compositional analysis results showed that, except for a few minor differences that are unlikely to be of biological significance, the grain and forage of GA21 corn were comparable in their composition to that of the control corn line and to conventional corn. Results from the poultry feeding study showed that there were no differences in growth, feed efficiency, adjusted feed efficiency, and fat pad weights between chickens fed with GA21 grain or with parental control grain. These data taken together demonstrate that Roundup Ready corn is as safe and nutritious as conventional corn for food and feed use.

Amino Acids↗
PubMed2000

Unusual extra-axial central nervous system involvement of non-Hodgkin's lymphoma: magnetic resonance imaging.

The MR imaging findings in a patient with non-Hodgkin's lymphoma with unusual involvement of the sella, pituitary stalk and left parasellar region are reported here. On the basis of the MR imaging findings, the initial differential diagnosis included invasive pituitary adenoma, a granulomatous lesion and en plaque meningioma. Trans-sphenoidal biopsy of the sellar mass showed chronic inflammatory changes and the patient was initially treated for tuberculosis. Because follow-up imaging showed the lesion to be progressive, a biopsy was done of an enlarged right inguinal lymph node. This revealed non-Hodgkin's lymphoma.

Adult↗
PubMed2000

Cranial epidural tuberculoma. A case report.

A 33-year-old patient with cranial epidural tuberculoma without history of tuberculosis is described. CT and MR imaging showed a lesion located on both sides of a right frontotemporal bone destruction with epidural extent. Except for a small necrotic core, the lesion enhanced intensely after contrast medium administration. Osteitis and subgaleal abscess were associated. The displaced dura mater delineated the epidural tuberculoma. Diagnosis was verified by histology and identification of Mycobacterium tuberculosis. After removal of the tuberculoma and combination therapy, there was a complete regression of abnormalities. Differential diagnoses are dural tuberculoma, focal tuberculous pachymeningitis and tuberculous epidural empyema.

Adult↗
PubMed2000

[Interest of free flaps for cranial base reconstruction].

We describe our experience in treating 7 patients who underwent skull base reconstruction with free flap (6 latissimus dorsi, 1 rectus abdominis) between October 1996 and November 1998. Four patients underwent temporal bone resection with auricular resection, 2 patients underwent anterior and middle cranial fossa resection, 1 patient underwent frontotemporal resection. There have been no failures of the free flaps and one cerebrospinal fluid leak. We advocate free flap reconstruction after temporal bone resection with auricular resection, and after anterior or middle cranial fossa resection when local flap options are not available or with complex dead space.

Adult↗
PubMed2000

[Hearing preservation in vestibular schwannoma surgery: indications, techniques and results in the literature since 1990].

Many authors have recently reported hearing preservation for approximately two-thirds of acoustic neuroma patients. The results have driven them to recommend early surgery for all patients whose hearing might be saved. Inversely, other authors advocate that MRI-screening may be beneficial in some patients and suggest surgery only in case of tumor growth or progressive hearing loss. In order to facilitate therapeutic decision making, we reviewed the techniques and results in the main papers dealing with hearing preservation in the course of acoustic neuroma surgery published since 1990. This analysis showed that the average percentage of useful hearing preservation is about 31%. It is however difficult to compare the different series due to the different methodologies used. This emphasizes the need for standardization of hearing selection and reporting criteria to a) identify factors predictive of success (tumor characteristics, preoperative hearing, monitoring, surgical pathways), and b) elaborate well accepted decisional guidelines (early surgery or MRI screening), notably for small and non-symptomatic tumors which show increasing prevalence.

Audiometry↗
PubMed2000

Motor and electrographic response of refractory experimental status epilepticus in rats and effect of calcium channel blockers.

Effects of various calcium channel inhibitors have been studied in lithium-pilocarpine model of status epilepticus. Status epilepticus was induced by administration of lithium chloride (3 meq/kg) followed 21 hr later by pilocarpine (30 mg/kg). Diltiazem (5 and 10 mg/kg) was not effective in delaying onset of convulsions. Verapamil (20 mg/kg) showed protection against lithium-pilocarpine-induced convulsions. The dihydropyridine nifidepine (2.5 and 5 mg/kg) did not show any protection in this model. Amlodipine (5 and 10 mg/kg) as partially protective. Flunarizine (10 and 20 mg/kg) delayed the onset of forelimb clonus and rearing and only 60% of the rats underwent status in the 20 mg/kg group. Pre-treatment of MK-801 led to a potentiation of the antiseizure activity of calcium channel inhibitors. The percent increase in amplitude at various time points with amlodipine pretreatment was significant only at the 30th min recording, and at the rest of the time frames was practically similar as the controls. It can be concluded that the anticonvulsant action of MK-801 can be enhanced by centrally acting calcium channel inhibitors.

Animals↗
PubMed2000

Sixteen-year experience with 1,000 heart transplants at UCLA.

1. The consecutive pre- and post-1994 eras have demonstrated improved survival for all age groups. This is linked to improved preservation methods, surgical technique and immunosuppression agents. 2. The use of marginal donor hearts for Status I and alternate elderly patients has followed the model of matching donor and recipient risk without affecting patient outcome and minimized the use of implantable assist devices. 3. A donor history of systemic gram-negative infection, hypertension, or traumatic intracranial bleeds was an important marker for risk. Younger age and shorter ischemia time could compensate for other hazards. 4. Heart transplantation in carefully selected elderly recipients yielded clinical results similar to those of younger patients with less rejection. 5. An adult alternate recipient list proved useful to prevent diversion of standard donors away from younger recipients. 6. Retransplantation for TCAD is acceptable but much less satisfactory for acute graft failure. 7. Trends show an increase in the use of implantable devices; refinement in technology for mechanical assist and replacement is forthcoming.

Adolescent↗