The key role of residue 5 in angiotensin II

The conformation–biological activity relationships in a series of angiotensin II analogs substituted in position 5 were studied. Results indicated that only analogs with β-branched residue in position 5 possess spectral and biological properties identical to that of parent angiotensin II.     

Haem ligands of the ferricytochrome c of Ustilago sphaerogena

The mammalian-type cytochrome c of the basidiomycete Ustilago sphaerogena contains in a single polypeptide chain of 107 residues, two histidine residues located at positions 18 and 33, and one methionine residue situated at position 80 (Bitar et al., 1972). The reaction of Ustilago ferricytochrome c with bromoacetate at neutral pH resulted in the modification of histidine-33, but not of histidine-18 or of the invariant methionine residue. The activities of Ustilago cytochrome c with mitochondrial cytochrome c oxidase and with NADH-cytochrome c reductase were unaltered by the modification. The equilibrium constants for the formation of low-spin complexes of the ferrihaem octapeptide of horse cytochrome c (residues 14-21, including the haem bound covalently to cysteines 14 and 17) with imidazole, N(2)-acetylhistidine and monocarboxymethyl derivatives of N(2)-acetylhistidine were determined spectrophotometrically. Alkylation of the imidazole side-chain group of N(2)-acetylhistidine resulted in a marked decrease in its ability to form low-spin ferrihaem complexes. These results indicate that in Ustilago ferricytochrome c in solution histidine-33 is not involved in the central co-ordination complex. Since side-chain groups of residues other than histidine and methionine do not appear to be involved in the central complexes of other mammalian-type cytochromes c (Hettinger & Harbury, 1964, 1965; Myer & Harbury, 1965) it is likely that in Ustilago ferricytochrome c in solution at neutral pH, the side-chain groups of histidine-18 and methionine-80 are involved in the central co-ordination complex. The latter is stable over the pH range 2.6-8.4.     

La forme scléronodulaire de la maladie de Hodgkin: expérience du CHU de Sherbrooke

Scleronodular type of Hodgkin''s disease: experience at the Centre hospitalier universitaire de SherbrookeThe nodular sclerosis type of Hodgkin''s disease appears to be a distinct clinical entity. However, the incidence, the initial localization of the tumour and the survival of the patients are variable. The present study was carried out on a group of 17 patients, all French Canadians living in the province of Quebec, from a total of 31 with Hodgkin''s disease, an incidence of 55%. There were more males (10) than females (7). The mean age of the group was 37 years, but that of the females was lower than that of the males. The mediastinum was involved at the onset in 47% of the patients. The initial staging (according to the classification of Rye) in 76% of the patients was I or II.Four patients showed disease below the diaphragm. The lungs were infiltrated three times, the spleen six times, and the liver five times. The duration of survival of the 17 patients was twice that of the patients with the three other types of the disease.     

Trichinosis: Thiabendazole in the Treatment of 11 Cases

We have studied 11 cases of acute human trichinosis; five of these patients were treated with thiabendazole. We have reviewed the laboratory data for these patients and described their course. This study has failed to show any definite effect of thiabendazole on the course of human trichinosis at the doses used. However, thiabendazole may have decreased the infectivity of the larvae which were embedded in the muscles of our patients.     

Diabetic Neuroarthropathy: Report of Four Cases

Diabetic neuroarthropathy was observed in four patients; these are the first cases of this nature reported in the Canadian medical literature. The criteria for this diagnosis included: (1) long-standing diabetes; (2) arthropathy, most frequently involving the foot, which shows deformity, shortening and ulceration without evidence of infection or peripheral circulatory failure; (3) abolition or diminution of pain on weight-bearing; (4) diabetic peripheral neuropathy with impaired sense of position or vibration and weak or absent deep tendon reflexes. Radiographic findings were similar to those in patients with Charcot''s arthropathy from any cause.Tabes dorsalis, leprosy, syringomyelia, myelodysplasia and the arthropathies of corticosteroid therapy were ruled out in these cases. In addition to conventional medical therapy the patients were treated by means of walking-casts for several months.Diabetic neuroarthropathy is probably more common than the medical literature would indicate. Diminished sensation in the lower limbs in diabetics of long standing appears to be the major factor contributing to this disorder.     

Histoenzymology of the developing human basal ganglia

Summary Oxidative and hydrolytic enzyme activities are present in the anlage of the human basal ganglia as early as the second month of embryonic life, and acetylcholinesterase activity appears during the sixth month of pre-natal life.Clinical Research Fellow of the Medical Research Council. Presently in the Department of Neurology, Indiana University, Medical School.     

Supplemental oxygen reduces right ventricular hypertrophy in monocrotaline-injected rats

We evaluated the possible contributory role of hypoxia in the development of monocrotaline-induced pulmonary hypertension. Male Sprague-Dawley rats were injected subcutaneously with monocrotaline (60 mg/kg) or saline in controls and were kept in oxygen-enriched (inspired O2 fraction of 0.35) or compressed air chambers. After 21 days, rats were anesthetized while spontaneously breathing room air, hemodynamic parameters and arterial blood gases were measured, and animals were killed. Right ventricular peak systolic pressures (RVPP), right ventricular-to-left ventricular plus septal weight ratios (RV/LV + S), hematocrits, lung dry weight-to-body weight ratios, and medial thickness of pulmonary arteries were significantly reduced in monocrotaline-injected rats exposed to mild hyperoxia compared with air. The air-exposed monocrotaline-injected rats had significantly more arterial hypoxemia than the other groups, and mild hyperoxia had no effect on any of the measured variables in saline-injected rats. To determine whether the effects of mild hyperoxia occurred early or late after monocrotaline injection, we moved separate groups of rats from air to mild hyperoxia and vice versa 10 days after monocrotaline injection. After 21 days, significant reductions in RVPP and RV/LV + S occurred only in rats exposed to mild hyperoxia during the latter 11 days after injection. Our findings suggest that hypoxia contributes to the development of pulmonary hypertension relatively late after monocrotaline injection in rats but that it does not influence the early injury.     

N-terminal portion of motilin determines its biological activity.

This study aimed to identify the portion of the 22 amino acid sequence of motilin responsible for the biological activity of the peptide. The contraction of rabbit duodenal muscle in vitro was measured when exposed to synthetic fragments of motilin corresponding to various sequences of the C- or N-terminal portions of the molecule. Fragments 2-22 or 3-22 (where the initial amino acids of the N-terminal ending were removed) were more than 1000 times less potent than the native molecule 1-22. Fragment 1-9 (where the last 13 amino acids located at the C-terminal side of motilin were removed) was devoid of any contractile capacity, while synthetic fragments whose C-terminal structure extended beyond the 1-9 motilin sequence maintained almost complete biological activity. N-terminal amino acid sequence 1-9 is therefore an essential determinant of the contractile activity of motilin.