Search PubMed⌕ Search

Biomedical subjects

J A Lynn

Publications and source records attributed to J A Lynn.

At least 19 recordsLinked to original sources
PubMed1998

Changing trends in the management of phaeochromocytoma.

BACKGROUND: The recent experience of a specialist endocrine surgery unit in the management of phaeochromocytoma is reviewed. METHODS: Over a 14-year period (June 1978 to June 1992) 43 patients (14 men, 29 women) with a mean age of 42 years were referred with phaeochromocytoma. RESULTS: Biochemical confirmation was usually by measurement of 24-h urinary vallinylmandelic acid. From 1980 venous sampling was replaced by computed tomography as the primary localizing procedure. 131I-meta-iodobenzylguanidine scintigraphy was used in all patients between 1984 and 1987, but selectively after that. With regard to the operative approach used, between 1978 and 1983 midline or flank incisions were used, and from 1984 to 1992 subcostal or posterior approaches were used predominantly. There was one operative (30-day) death. One patient died 24 months after operation from recurrent malignant phaeochromocytoma, and three patient died during follow-up from unrelated causes. The remaining patients (mean follow-up 30 months) have no evidence of recurrent phaeochromocytoma, although four remain on antihypertensive medication. CONCLUSION: Improved imaging of phaeochromocytoma obviates the need for transperitoneal exploration, allowing selected phaeochromocytomas to be successfully managed using an extraperitoneal approach.

Adolescent↗
PubMed1998

Conn syndrome: 14 year's experience from two European centres.

OBJECTIVE: To evaluate the long term results of adrenalectomy for primary hyperaldosteronism. DESIGN: Multicentre retrospective cohort study. SETTING: Two university hospitals, UK and Italy. SUBJECTS: 55 patients who presented with a mean (SD) preoperative blood pressure of 181/110 (21/10) mmHg and a mean (SD) potassium of 2.8 (0.4) mmol/L (range 1.6-4) during the period October 1978 to October 1992. INTERVENTIONS: Unilateral adrenalectomy, usually by the extraperitoneal approach. Adrenalectomy was total in all but nine cases. MAIN OUTCOME MEASURES: Accuracy of preoperative investigations for the diagnosis and localisation of the lesions, histology, morbidity and mortality, long term outcome (mean follow up 8.8 years). RESULTS: Computed tomography gave a diagnostic accuracy for unilateral lesions of 88%, the postural stimulation test 80%, norcholesterol scintigraphy 84%, and ultrasonography 57%. Histological examination showed carcinoma (n = 1), diffuse hyperplasia (n = 2), nodular hyperplasia (n = 11) including 5 with macronodular hyperplasia, double adenoma (n = 1) and single adenoma (n = 40). No patient died, and 10 developed minor complications. At the latest follow-up 44/52 patients with benign unilateral lesions (85%) have been cured by adrenalectomy. CONCLUSIONS: Our results confirm the safety of the extraperitoneal approach, and suggest that the improvement in the accuracy of preoperative investigations has allowed a careful selection of patients with the consequent amelioration of the long term outcome of surgery for Conn's syndrome. As laparoscopic adrenalectomy is currently advocated as the operation of choice for surgically-remediable mineralocorticoid excess, its long term results will have to be comparable with these standards.

Adrenalectomy↗
PubMed1996

Surgical management of gastrointestinal endocrine tumours.

The surgical management of gastrointestinal endocrine tumours must involve a multidisciplinary approach. The importance of accurate diagnosis, rendering the patient safe, and, in our opinion, localizing the tumour(s) before embarking on surgery cannot be overemphasized. Surgery is the only available treatment for cure. Occult primary tumours are now rarely a problem with novel imaging techniques, which can also improve detection and hence clearance of local spread. Surgical management in extensive metastatic or multicentric disease is less rigidly defined, and is dependent on the endocrine syndrome. A better understanding of tumour pathology, for example in MEN 1, has not always simplified matters. An appreciation of the benefit of chemotherapy, use of somatostatin analogues and hepatic artery embolization are vital to target appropriate palliative surgery. Hepatic transplantation may have an increasing role in the future. Surgical strategies must adapt to new medical treatments. If therapeutically relevant, advances in tumour biology (for example somatostatin receptor subtypes and growth factors) will influence surgical strategies in the future.

Diagnostic Imaging↗
PubMed1996

Localization of insulinomas by selective intraarterial calcium injection.

This study examines the role of selective intraarterial calcium injection and hepatic venous sampling in the localization of insulinomas. Seven patients were studied. In all cases, ultrasound and computerized tomography scans were either negative or equivocal. Calcium gluconate was injected directly into the arteries supplying the pancreas after standard selective angiography. Insulin levels were measured in samples taken from the right hepatic vein before and 30, 60, 90, 120, and 180 s after each injection. Two doses were used, 0.025 milliequivalents Ca/kg (1 mg/kg) for the first two subjects and 0.00625 milliequivalents Ca/kg (0.25 mg/kg) for the remaining five subjects. Serum insulin levels rose at least 2-fold, the proposed diagnostic rise, from basal in six subjects; one test was negative. Of the six positive studies, a diagnostic rise was seen only in one artery in five cases. One patient did not undergo surgery. In the remaining five patients, surgery confirmed the position and histology of the tumor. The one patient with a diagnostic rise in more than one artery, however, had residual disease after surgery. The seventh subject referred specifically for localization had a negative calcium stimulation study and a subsequent diagnosis of intermittent sulfonylurea abuse was made after a positive screen. The present study shows that preoperatively, selective intraarterial calcium injection with hepatic venous sampling is a powerful technique for the localization of insulinomas. Smaller doses of calcium than previously reported can be used and may reduce the risk of hypoglycemia during the procedure.

Adult↗
PubMed1996

Relative DNA.

Explore the source record for details and available documents.

DNA↗
PubMed1994

Localization and surgical management of insulinoma.

Over a 14-year period 34 patients were referred for surgical treatment of insulinoma. The diagnosis was confirmed by demonstrating hypoglycaemia with inappropriate hyperinsulinaemia during prolonged fasting. Selective visceral angiography localized 30 solitary benign insulinomas and two carcinomas. In two patients with islet cell hyperplasia, angiography demonstrated a single lesion only. Ultrasonography had a sensitivity of 15 per cent and computed tomography a sensitivity of 24 per cent in the localization of tumours. All patients but one were treated by operation. Eighteen tumours were enucleated and 13 (including both patients with islet cell hyperplasia) were treated by distal pancreatectomy. Two patients underwent negative primary exploration; both had single adenomas removed at re-exploration. There were no operative deaths but nine patients (predominantly those undergoing pancreatic resection) had complications. Thirty-one patients were symptom-free following operation at a mean follow-up of 16 months.

Adolescent↗
PubMed1986

Imaging of metastatic medullary carcinoma of the thyroid with 131I-meta-iodobenzyl guanidine.

The uptake of 131I-MIBG by medullary carcinoma of the thyroid was studied in six patients after total thyroidectomy in whom persistent raised plasma calcitonin levels were indicative of residual disease. The only patient in whom any activity in a possible metastasis was seen had by far the highest level of circulating calcitonin of the group and in contrast one patient with a presumptive metastatic deposit showed no uptake of MIBG into it. In conclusion the uptake of 131I-MIBG by medullary carcinoma of the thyroid is unreliable and unpredictable.

3-Iodobenzylguanidine↗
PubMed1981

Subtotal parathyroidectomy for primary chief cell hyperplasia of the multiple endocrine neoplasia type I syndrome.

To evaluate the efficacy of subtotal parathyroidectomy (STP) in the treatment of primary hyperparathyroidism due to multiple gland disease, 12 patients with multiple endocrine neoplasia (MEN) type I syndrome were reviewed out of 132 patients undergoing parathyroidectomy. Each patient had yearly follow-up examinations and calcium determinations for a minimum of four years except for one patient who died one year after S.T.P. Permanent hypoparathyroidism occurred in three patients. Two patients remained persistently hypercalcemic, and two patients developed recurrent hypercalcemia. One patient required oral administration of calcium and vitamin D for ten years following STP before recurrent hypercalcemia developed. Another patient was normocalcemic for three years before recurrent hypercalcemia was noted. Only five of these 12 patients remain normocalcemic without need of calcium and vitamin D therapy. In patients with MEN type I, the long-term results of STP are less than satisfactory. Not only is it difficult to gauge how viable parathyroid tissue must be left to prevent both permanent hypoparathyroidism and persistent hyperparathyroidism but there is also a long-term risk of recurrence.

Calcium↗
PubMed1981

Reoperations for hyperparathyroidism.

During a 20 year period, 27 patients have undergone reoperations for primary hyperparathyroidism. Hypercalcemia has been successfully controlled in 21 of the 27 patients after a total of 64 operations. Reasons for failure at initial exploration included surgical error in 12, multiple gland disease in five, unusual parathyroid gland location in five, carcinoma of the parathyroid gland in two and unknown in three. A variety of techniques were used to localize missing parathyroid glands prior to reoperation. Selective venous sampling was the most helpful but gave correct localizing information in only nine of 18 patients. Postoperatively, hypoparathyroidism was temporary in two patients and permanent in four. Recurrent laryngeal nerve injury was temporary in one patient, permanent and unilateral in two and bilateral in one patient. Reoperations for hyperparathyroidism are associated with increased morbidity and decreased success. Most importantly, failure at the initial operation is preventable in most patients.

Adolescent↗