Search

These investigations were conducted to measure the prebreakdown current and breakdown voltage between stainless steel electrodes using 50 Hz alternating and direct voltages. The measurements were made at room temperature and liquid nitrogen temperature using uniform field electrodes. The range of electrode spacings for the current measurements was 0.1-2.1 mm and for the breakdown voltage with temperature and electrode spacing was very similar with both types of voltage application. Also with both types of voltage, the prebreakdown current obeyed a cold-cathode emission law, analytically similar to the Fowler-Nordheim relation. In both cases an ambient pressure greater than about 10-6 Torr caused the current to be suppressed though this was found to be a reversible effect.

The cellular infiltrate of the proximal jejunum has been compared between 20 subjects without gastrointestinal disease, 20 subjects with ulcerative colitis, and 26 subjects with Crohn's disease. A significant increase (P smaller than 0.001) in the plasma cell infiltrate was noted in subjects with ulcerative colitis and a more marked increase in subjects with Crohn's disease (P smaller than 0.001). Such increases may be relevant to raised serum IgA levels following panproctocolectomy for ulcerative colitis or recurrence in the small intestine in Crohn's disease.

These investigations were conducted to measure the prebreakdown current and breakdown voltage between aluminium, copper, stainless steel, niobium and gold electrodes in vacuum and uniform fields at room, liquid nitrogen and liquid helium temperatures. The range of electrode spacings for the current measurements was 0·1-4 mm and for the breakdown voltages was 0·1-1·8 mm. The results showed that the current decreased with decreasing electrode spacing and decreasing cathode temperature. They also showed that the breakdown voltage increased with increasing electrode spacing and decreasing cathode temperature. It was shown that the prebreakdown currents obeyed a cold-cathode emission law analytically similar to the Fowler-Nordheim relation and that the changes in values could be explained by changes in the field intensification factor and emitting area. The breakdown voltages indicated that the same mechanism prevailed at all spacings and temperatures and suggested that breakdown was initiated by the cold-cathode emission currents causing an instability at either the anode or the cathode.

The result of a prospective trial of 40 patients with duodenal ulcer treated either by proximal gastric vagotomy (antrum innervated) or by selective vagotomy (antrum denervated) shows that they are equally effective in reducing gastric acid and pepsin secretion. Preservation of antral innervation by proximal gastric vagotomy reduces gastric secretion as effectively as denervation of the entire stomach.

The accuracy of early radiology in patients with acute gastrointestinal haemorrhage has been studied by a comparison of the radiological opinion with the established diagnosis. A full examination has proved safe and uncomplicated with a high degree of accuracy and no false-positive results. Analysis of the errors shows that the presence of residue discourages the radiologist from making the correct diagnosis, and modification of the standard bariummeal technique may be needed to overcome this difficulty.

In a study of a group of 325 blood donors between the ages of 18 and 65 years, the total leucocyte and polymorph counts of the females aged 50 to 65 years were found to be significantly lower than those of the corresponding group of male donors. In the whole series of female donors, there were significantly lower total leucocyte and lymphocyte counts with increasing age and a less significant (P [unk] 0·1) fall in the polymorph count. No age variation in the male counts was found. Analysis of large numbers of leucocyte counts performed on hospital patients has confirmed the sex difference in the total leucocyte count found in the blood donors. The factors responsible for the differences are discussed.

A comparison is made of the immediate and long term mortality of colectomy and ileostomy between 73 patients who had Crohn's colitis and 442 who had ulcerative colitis. The immediate mortality in Crohn's disease is 4%. In ulcerative colitis it is 10%, chiefly because of the higher proportion of emergency operations. The late mortality in both groups is 10%, chiefly as a result of recurrence of Crohn's disease or the sequellae of colonic malignancy present at the time of colectomy for ulcerative colitis. A further comparison is made between the postoperative course of the 64 surviving patients with Crohn's disease and a comparable sample of 65 patients who had an ileostomy for ulcerative colitis in the same era. There was a similar incidence of postoperative septic complications in the two groups (35%). The readmission rate was twice as high in the Crohn's disease patients. Ileostomy reconstruction for mechanical complication was needed in 21 patients with Crohn's disease compared with 6 with ulcerative colitis. Further ileal resection was required for recurrent disease on another 25 occasions in the patients with Crohn's disease but never in those with ulcerative colitis. Long therm review graded the clinical status as excellent or good in 70% of those with Crohn's disease compared with 95% with ulcerative colitis.

Xenon-133 has been widely used for the measurement of regional cerebral blood flow by both the carotid injection and inhalation methods. The principal disadvantage of Xenon-133 is the low energy of the radiation which is very readily scattered. The energy of the radiation scattered at 180° (the backscatter peak) depends on the energy of the primary beam. The back- scatter peak of the 81 keV of 133Xe occurs at 69 keV. Since the resolution of a sodium iodide detector at 80 keV is usually about 25 keV, counting over the full photopeak includes a substantial amount of scattered radiation and there will also be a contribution from lead X-rays at 73 keV, if the collimators contain lead. It is not possible to eliminate the scattered energy without a substantial loss in the sensitivity even by accepting only the upper portion of the photopeak. Wilkinson (personal communication) has indicated that if the lower discriminator gate is set at 77 keV approximately 23% of the counts recorded by the detector come from outside the “optical” field of view of the collimator. Most of the papers on local blood flow do not specifically indicate that counting conditions were such as to exclude scattered radiation. The results ascribed to regional areas as measurements of local blood flow are therefore of questionable accuracy.

The first case of duodenal perforation during gastroscopy is reported. The patient's symptoms were mild in contrast to the dramatic picture of perforated peptic ulcer. He developed a pneumoperitoneum, pneumomediastinum, and, in addition, subcutaneous emphysema of the neck—signs more commonly associated with oesophageal rupture than perforation of the duodenum. The aetiology of these signs and the prevention of this complication are discussed.