Functional MRI shows activation of the medial preoptic area during sleep.

Changes in the activity of the basal forebrain sleep regulating areas were studied noninvasively in conscious rats by employing functional magnetic resonance imaging (fMRI). Sleep-wakefulness (S-W) stages were identified with the help of electrophysiological recordings carried out simultaneously. An increase in the signal intensity was observed in the medial preoptic area (mPOA) during sleep indicating a heightened activity of neurons in this area. In some rats, there was a decrease in the activity of the fronto-parietal cortex. The sleep-induced increase in activity in the mPOA and decrease in the fronto-parietal cortex are in relation to their levels in the awake state. The findings helped to localize the critical area for the maintenance of slow wave sleep at the mPOA. These results further corroborate some of the previous suggestions based on neurotoxic lesion, chemical stimulation and electrophysiological recordings.

Stereotaxic assembly and procedures for simultaneous electrophysiological and MRI study of conscious rat.

A stereotaxic restraining assembly was designed and developed for simultaneous electrophysiological recordings and functional MRI (fMRI) data acquisition from a conscious rat. The design of the nonmagnetic stereotaxic apparatus facilitated the restraining of head and body of the unanesthetized conscious animal during MRI experiments. The apparatus was made of Teflon and Perspex materials with an appropriate size and shape for a 4.7 T / 40 cm animal MRI scanner. Electrodes made from nonmagnetic silver wire were implanted on the skull for recording the electroencephalogram (EEG), the electro-oculogram (EOG), and the electromyogram (EMG), while polycarbonate screws were used for anchoring the electrode assembly. There were no major distortions or artifacts observed in the electrophysiological tracings and MR images. Electrophysiological recordings during fMRI acquisitions are useful to study different neurophysiological mechanisms of sleep and pathophysiology of seizure activity. Integration of electrophysiological recordings (with their good temporal resolution) and MRI (with its superior spatial resolution) is helpful in characterizing the functional state of different brain regions.

Relationship of symptom duration and survival in patients with carcinoma of the colon and rectum.

The generally held belief that early diagnosis and treatment are associated with a greater proportion of localized tumors and better prospects of salvage is not supported in carcinoma of the large intestine. This study is not to be interpreted to mean that purposefully delayed treatment in an individual patient will improve his chances of survival. Its purpose is to place the emphasis on early diagnosis in its proper perspective. Entirely different methods of diagnosis need to be developed so as to be able to diagnose carcinoma of the large intestine during its presymptomatic phase.

Results of Whitehead operation.

Eighty-four patients underwent the Whitehead procedure for extensive hemorrhoids. Early postoperative complications, excluding urinary difficulties, developed in six patients. Long-term results were within an acceptable range.

Comparison of results of treatment of fistula-in-ano.

The results of treatment of 137 consecutive patients with fistula-in-ano are presented. Sixty-eight were treated by the 'lay-open' technique and 69 by the Parks technique, the two groups being comparable. The results slightly favour the Parks technique.

Single-layer anastomosis of the colon and rectum.

A total of 116 one-layer end-to-end anastomoses of the colon and the rectum in 112 patients were studied. Three patients died postoperatively (2.6 per cent). Significant disruption of anastomosis requiring a diverting colostomy occurred in five patients. The study is presented to draw attention to the safety of the single-layer anastomosis.

Experience with single-layer rectal anastomosis.

Anastomotic dehiscence following resection of the large intestine is a serious complication. Satisfactory results of single-layer anastomosis depend upon meticulous technique and a scrupulously clean colon. Out of 65 single-layer anastomoses involving the rectum, significant leakage occurred in 4 patients. The results are reported in order to draw attention to the safety and efficacy of one-layer anastomosis.

Urgent hemorrhoidectomy for hemorrhoidal thrombosis.

Sixty-five patients underwent hemorrhoidectomies for acute thrombosis. All biopsy specimens contained intravascular thrombi. Early postoperative complications included urinary difficulties and bleeding. Late postoperative complications included anal stenosis.