Demonstration of a CW diode-pumped Ar metastable laser operating at 4 W.

Optically pumped rare gas lasers are being investigated as potential high-energy, high beam quality systems. The lasing medium consists of rare gas atoms (Rg=Ne, Ar, Kr, or Xe) that have been electric discharge excited to the metastable np5(n+1)s P32 state. Following optical excitation, helium (He) at pressures of 200-1000 Torr is used as the energy transfer agent to create a population inversion. The primary technical difficulty for this scheme is the discharge production of sufficient Rg* metastables in the presence of >200 Torr of He. In this Letter, we describe a pulsed discharge that yields >1013 cm-3Ar* in the presence of He at total pressures up to 750 Torr. Using this discharge, a diode-pumped Ar* laser providing 4.1 W has been demonstrated.

The 14C-urea breath-test for the detection of gastric Campylobacter pylori infection.

A breath-test has been developed for the detection of gastric infection with Campylobacter pylori. Urea that is labelled with carbon 14 is administered to a fasting patient and the patient's breath is sampled for radioactivity over the following 30 minutes. If C. pylori is present in the patient's stomach, urease activity causes hydrolysis of the urea and the 14C is absorbed as carbon dioxide. This carbon dioxide enters the patient's bicarbonate pool and eventually is excreted in the breath. The results are expressed as a percentage of the administered dose/mmol carbon dioxide x kg body weight. Sixty-three patients who were undergoing endoscopy were studied. The radioactivity in exhaled breath which was sampled within five minutes of 14C-urea administration was attributed to the presence of urease enzyme in mouth organisms and was discounted. The time-radioactivity curves for breath samples from five to 30 minutes after the administration of 14C-urea gave an excellent separation between subjects with negative results of the examination of gastric-biopsy samples and patients with microbiological and histological evidence of infection with C. pylori. The area under the time-radioactivity curve at between five and 30 minutes after the administration of 14C-urea in 24 patients with negative microbiological results was 6.9 +/- 4.4 area units; in 35 of 39 patients with positive microbiological results, this area was greater than 40 area units. Measured against the results of the microbiological examination of gastric-biopsy samples, the sensitivity of breath-testing was 90% and the specificity was 100%. Measured against the results of histological examination for the presence of C. pylori infection, breath-testing had a sensitivity of 94% and a specificity of 93%. A positive breath-test result also correlated well (P = 0.0001) with the serological antibody test-result. The role of non-invasive tests--enzyme-linked immunosorbent assays and 14C-urea breath-testing--in the management of gastritis and peptic ulcer disease is discussed. We consider that the 14C-urea breath-test has an important role in the noninvasive confirmation of gastric infection with C. pylori and in the follow-up of patients after treatment.

Prospective double-blind trial of duodenal ulcer relapse after eradication of Campylobacter pylori.

100 consecutive patients with both duodenal ulcer and Campylobacter pylori infection were followed up to see whether eradication of C pylori affected ulcer healing or relapse. Patients were randomly assigned to 8 weeks of treatment with cimetidine or colloidal bismuth subcitrate (CBS), with tinidazole or placebo being given concurrently from days 1 to 10, inclusive. Endoscopy, biopsy, and culture were done at entry, in weeks 10, 22, 34, and 62, and whenever symptoms recurred. There was no maintenance therapy. C pylori persisted in all of the cimetidine-treated patients and in 95% of those treated with cimetidine/tinidazole, but was eradicated in 27% of the CBS/placebo group and 70% of the CBS/tinidazole group. When C pylori persisted, 61% of duodenal ulcers healed and 84% relapsed. When C pylori was cleared 92% of ulcers healed (p less than 0.001) and only 21% relapsed during the 12 month follow-up period (p less than 0.0001).

Familial idiopathic megaduodenum.

Familial idiopathic megaduodenum is an uncommon condition which may be associated with other visceral abnormalities. Antineuronal antibody directed against guinea-pig skeletal muscle was found in one member of the family suffering from megaduodenum, in whom degeneration of the Auerbach's and Meissner's plexuses was documented. The significance of this finding is unclear. Management of the complaint is problematic. Despite shortcomings of surgical treatment, surgery nevertheless has an important role to play when medical treatments fail.

Evaluation of cultural techniques for isolating Campylobacter pyloridis from endoscopic biopsies of gastric mucosa.

One hundred and three gastroscopic biopsies from 80 patients were cultured for Campylobacter pyloridis and studied histologically. Active chronic gastritis, as shown by the presence of polymorphonuclear leucocytes, was diagnosed in 51 biopsies and C pyloridis was found in 47. Sixteen gastric biopsies showed normal histology (no inflammation); C pyloridis was detected in only one of these, and a second biopsy taken from this patient at the same time showed active gastritis. Biopsies could be kept at 4 degrees C for five hours without loss of viability of C pyloridis. An inoculum made by grinding the biopsy in a ground glass grinder consistently gave a much heavier growth of C pyloridis than one made by mincing the specimen. The campylobacter supplement ferrous sulphate, sodium metabisulphite, sodium pyruvate (FBP) (Oxoid) was inhibitory for some isolates; the inhibitory component was found to be sodium metabisulphite. Contaminants, but not C pyloridis, were inhibited by the incorporation of vancomycin 6 mg/l, nalidixic acid 20 mg/l, and amphotericin 2 mg/l, but higher concentrations inhibited C pyloridis. Undried plates kept in a plastic container at room temperature for up to two weeks were as satisfactory as freshly poured plates for the isolation of C pyloridis.

Serum pyridoxal in patients with gastric pathology.

Fasting serum pyridoxal was assayed by an automated microbiological system in 60 patients investigated for dyspepsia, patients with active peptic ulceration being excluded from the study. Gastritis was present in 30 patients, gastric carcinoma in 16, six patients had benign polyps, and, in eight patients, radiology, endoscopy, and biopsy failed to shown any abnormality. Of the 52 patients with gastric pathology, 44 had a low serum pyridoxal.

Serum pyridoxal in patients with rheumatoid arthritis.

Abnormalities of tryptophan metabolism have been reported in patients with rheumatoid arthritis (RA) and it has been suggested that these abnormalities are the result of disordered vitamin B6 metabolism. Fasting serum pyridoxal, assayed by an automated microbiological system, was found to be below normal in 35 out of 42 patients with RA while a similar abnormality was found in 8 out of 35 patients with osteoarthrosis (OA). Within the RA group the abnormality could not be related to the age, sex, or drug therapy of individuals but of the 8 patients with OA and a low serum pyridoxal, 7 were receiving indomethacin either alone or in conjunction with aspirin.

Serum pyridoxal in active peptic ulceration.

Fasting serum pyridoxal was assayed by an automated microbiological system in 50 patients with endoscopically confirmed active peptic ulceration. Thirty patients had gastric ulceration, 14 had duodenal, four had pyloric canal ulceration, and two had both a gastric and a duodenal ulcer. Serum pyridoxal was below normal in 28 of the gastric ulcer group and in one of the duodenal ulcer group. No difference in the age, sex, drug, alcohol intake, or diet could be distinguished between those two groups.