Removal Of Pituitary Tumor Research Articles

A Comparative Interaction of Epinephrine with Enflurane, Isoflurane, and Halothane in Man

Forty-eight patients undergoing transphenoidal removal of pituitary tumors received submucosal injections of epinephrine in saline solution during halothane, enflurane, or isoflurane anesthesia. Twelve additional patients received epinephrine in 0.5 percent lidocaine while anesthetized with halothane. Positive evidence of ventricular irritability was given by the appearance of 3 or more premature ventricular contractions during or following injection. Positive or negative responses were plotted against the total dose of epinephrine in mug/kg body weight. From these data, the dose producing a positive response in 50 percent of patients (ED50) was calculated. An ED50 of 2.1 mug/kg for halothane, 3.7 mug/kg for halothane-lidocaine, 10.9 mug/kg for enflurane, and 6.7 mug/kg for isoflurane indicates the relative safety of these agents when epinephrine is injected for hemostasis. The data also suggest that lidocaine given with the epinephrine protects against ventricular arrhythmias.

Hypophyseal function in the operative and postoperative phases after removal of pituitary tumours

In 47 patients with various pituitary tumours plasma cortisol, LH, FSH, prolactin, and GH were measured by radioimmunoassays to investigate anterior pituitary function. In 14 subjects LH--RH and TRH stimulation tests were performed to assess pituitary reserve before, during, and after surgical therapy. The mean cortisol levels were raised during and after the operative procedures until the 14th postoperative days. In patients with functionless tumours the other hormone concentrations remained nearly unchanged and in the normal ranges. After the removal of the tumour a rapid decrease in hormone levels, as might be expected, was rare, with the exception of the GH and prolactin levels in patients with hypersecretion. The postoperative stimulation tests showed a maintained secretory pituitary reserve due to active tissue left behind after operative removal of the tumour.

Intraoperative demonstration of the neoplasm cavity in open transsphenoidal pituitary gland surgery using dimer X

The problems of the complete removal of pituitary fossa tumours by transsphenoidal approach and its risk of producing a rhino-liquorrhea are well known. Concerning these difficulties a control of the operative procedure by intrasellar application of contrast medium is recommended.

Serial plasma growth hormone concentration during selective removal of pituitary tumors in acromegaly.

✓ The pituitary function of two patients with acromegaly was monitored before, during, and after selective transnasal pituitary adenomectomy. The purpose of the study was to verify the efficacy of this technique, and to see if there was normal function in the residual pituitary tissue. Following surgery, both patients showed clinical improvement with no evidence of significant anterior or posterior pituitary dysfunction. Concentrations of plasma growth hormone obtained serially during surgery were elevated prior to tumor removal but fell precipitously after adenomectomy. The half-life for immunoreactive growth hormone in these patients was less than 35 minutes. We conclude that selective transnasal pituitary adenomectomy is an effective treatment for pituitary tumors. Furthermore, our data suggest that the pituitary tumor in these patients did not arise because of excessive stimulation by hypothalamic growth hormone-releasing factor.

Endonasal transsphenoidal approach to pituitary surgery: experience of 55 cases

Transsphenoidal approach to sella is not a new approach. In the last 100 years it has gone numerous changing refinements from using headlight to microscope and more recently the sensitive endoscope. In this prospective study, all patients with pituitary tumor who underwent endonasal transsphenoidal pituitary surgery during the period of January 2006 to July 2009 in the department of neurosurgery, Dhaka Medical College Hospital and Islami Bank Central Hospital, Dhaka, Bangladesh were included. Among the 55 patients 36 cases were operated by combined endoscopic and microscopic techniques and 19 cases were operated by endoscope only. Total 73 procedures were done in 55 patients. Age range was 17 years to 70 years. Follow up period was 03 months to 42 months (mean 14.2 months) .Male: female was almost 1:1. Clinical features were pituitary apoplexy, pituitary apoplexy with 3rd/+6th cranial nerve palsy, headache, amenorrhea, loss of libido, galactorrhoea, gynecomastia, weight gain and psychosis. Visual impairment was in 35 cases. Functioning adenoma was 21 and non functioning adenoma was 34 cases. Among the functioning adenoma acromegaly was seen in 12 cases, gigantism in 01 case, prolactinoma in 05 cases, Cushing's disease 03 cases. Purely sellar tumor was 15, sellar & suprasellar 35 and sellar & parasellar 11 cases. Microscopic plus endoscopic techniques used in 54 procedures. Purely endoscopic procedures were 19. Complete removal of tumor in single stage was done in 33 cases. Complete removal with more than one stage surgery in 13 cases. In our initial cases of the series, we exposed the sella endonasally with endoscope then we used microscope for the rest of the surgery. In the later part of the series we gained experience and confidence for removal of pituitary tumor with an endoscope completely. The rate of diabetes insipidus occurred in 11(20%) cases and all are transient. Postoperative CSF leak was noted in 10(18%) cases. Patient with ocular palsy improved post operatively within 6 weeks. Among non functioning adenoma that were removed completely (30 cases) recurrence occurred in three cases. Eleven patients were stable in vision as preoperative. Other showed visual improvement to variable extents. Key words: Pituitary surgery; Endonasal; Transsphenoidal; Microsurgery; Endoscopic surgery. DOI: 10.3329/bjo.v15i2.5056 Bangladesh J Otorhinolaryngol 2009; 15(2): 45-49

Factors affecting alternate pathways of corticosteroid excretion: Possible catabolite repression phenomena in man

By employing a method of sequential extraction of β-glucuronidase hydrolyzed urine it was possible to quantitate the excretion of “less polar” 17-OH, 20, 21-ketols (tetrahydrocortisol and tetrahydrocortisone) and of polar 17-OH, 20, 21-ketols. In normal subjects the excretion of the less polar fraction exceeds the polar fraction by a 2 1 ratio. In a patient with a recent infarction of a pituitary tumor and subsequent removal of the tumor, the urinary excretion pattern was found to be abnormal, with a greater excretion of polar 17-OH, 20, 21-ketols and essentially zero levels of the less polar 17-OH, 20, 21-ketols. While the patient was maintained on replacement dosages of dexamethasone, intermittent measured doses of cortisol were also found to lead to the urinary excretion of more 17-OH, 20, 21-ketols in the polar fraction than in the less-polar fraction. After the patient was given an infusion of glucose and a small amount of insulin it was found that the excretion pattern after ingestion of cortisol became essentially normal. The change was due to a 63 per cent decrease in the polar steroid pathway and a 23 per cent increase in the less-polar steroid pathway. On substitution of daily cortisol for replacement it was found that the excretion pattern was essentially normal. The alternate pathways described are dependent on two different enzyme systems, the pathway to the “less-polar” steroids is dependent on reduction of the Δ 4, 3-ketone structure by a hepatic Δ 4, 5 hydrogenase and a 3α hydrogenase. The formation of the polar metabolites is dependent on certain hepatic microsomal hydroxylases. The glucose effect and the effect of maintenance doses of cortisol on these alternate pathways are discussed in terms of enzyme induction and repression. The possibility that the glucose effect noted here is an example of the “catabolite repression” phenomena affecting corticosteroid metabolism is considered.