Delayed clearance of specific polymeric IgA immune complexes in patients with IgA nephropathy

The presence of multimeric (polymeric and monomeric) IgA immune complexes (IC), detected by Raji cell assay and by the inhibition binding assay, as well as the specific polymeric IgA-IC were examined before and after the ingestion of 100 g protein. A rise in multimeric IgA-IC occurred in three out of seven controls with a peak at two to four hours after the meal, being cleared thereafter. The amount of multimeric IC present at fasting in four of six patients diminished at two to four hours after food challenge reaching a new peak around six hours. In both controls and patients, IC containing antibodies against diet antigens (e.g. ovalbumin) paralleled those of multimeric IgA-IC. In controls the specific polymeric IgA-IC presented a maximal peak with distribution similar to multimeric IgA-IC, but with a faster disappearance from the circulation. By contrast, polymeric IgA-IC remained elevated 24 hours after food ingestion in most patients. These results suggest that a defect in the hepatic clearance of circulating polymeric IgA-IC exists in patients with IgA nephropathy.

The effect of the injection of a synthetic platelet-activating factor (PAF-acether) on the fate of IgG aggregates in mice

The effect of the injection of a synthetic platelet-activating factor (PAF-acether) upon the fate of exogenous immune aggregates was studied in normal mice. When animals received 0.5 μg of PAF-acether following the administration of 5 μg heat-aggregated human IgG (A-IgG), a 50% increase of clearance velocity was observed during the initial 5 min; thereafter, between 15 and 30 min, there was a marked increase in blood levels of immune aggregates which paralleled the increase in plasma volume observed at those times. As regards the effect of the infusion of PAF-acether on the distribution of A-IgG in the organs, hepatic uptake was not affected, kidney uptake was reduced during the first 15 min, and lung and spleen showed only minor variations. When animals were injected with 0.5 μg PAF-acether, skin trapped aggregates showed a 73% increase above control values at 5 min, followed by a fall to control values coincidently with the flood back of the aggregates into the circulation and the increase in blood volume. The injection of lower doses of PAF-acether (0.05 μg) or Diazoxide (1.5 mg) did not induce any change on the skin trapping of aggregates. In conclusion, the powerful action of PAF-acether on vascular permeability allows a reversible deposition of immune aggregates in the skin which is followed by the flood back of this material into the circulation when its pharmacological action subsides. These findings may be of some relevance to the understanding of the dynamic processes involved in the deposition of immune complexes in tissues, especially as regards skin vessels.

Handling of soluble IgA aggregates by the mononuclear phagocytic system in mice. A comparison with IgG aggregates

We have studied the fate of soluble stable aggregates of human IgA (A-IgA) and IgG (A-IgG) after their injections in mice, as well as in vitro catabolism by liver, kidney and peritoneal macrophages. The half-life of the fast component of blood clearance was similar for both aggregates. However the half-life of the slow component of A-IgA clearance was significantly slower than A-IgG (t1/2 10 . 03 v. 7 . 52 hr, respectively). The A-IgA deposited in liver and kidney was removed significantly more slowly than A-IgG. Studies in isolated liver and kidney slices suggest that this could be due to the impaired catabolism of A-IgA as opposed to that of A-IgG. Interestingly the kidney hardly participates in the processing of A-IgA. At the three doses employed (1, 5 and 10 micrograms of both aggregates) peritoneal macrophages bound and catabolised significantly less amount of A-IgA than A-IgG. Complement seems to have no role in the processing of A-IgA by peritoneal macrophages unlike that observed with A-IgG. It is suggested that the impairment in handling of A-IgA by the mononuclear phagocytic system could provoke their persistence in the circulation and deposition at sites susceptible to injury. These results may be of some relevance for the understanding of physiological IgA-IC (immune complex) clearance and for the pathogenesis of IgA-related diseases.

Plasma renin activity and urinary sodium excretion as prognostic indicators in nonazotemic cirrhosis with ascites

Azotemia is an ominous prognostic sign in cirrhosis with ascites. To investigate whether other renal disturbances are also prognostically significant, we studied the renin-aldosterone system and sodium excretion (UNaV) in 75 patients who had nonazotemic cirrhosis with ascites and related these to survival. On the basis of plasma renin activity patients were classified in two groups. Group I included 34 patients with normal renin activity (1.13 +/- 0.69 ng/mL . h) and Group II, 41 patients with high renin activity (7.46 +/- 3.86 ng/mL . h). The two groups differed significantly (p less than 0.001) in plasma aldosterone, UNaV, and wedged hepatic venous pressure but not in clinical features, liver function, glomerular filtration, and renal plasma flow. Patients of Group I lived significantly longer than those of Group II (the 50% survival rates were 28 months and 6 months, respectively). Survival curves obtained after grouping the patients according to UNaV (higher and lower than 10 meq/d) were almost identical to those obtained according to renin activity. The study results indicate that plasma renin activity and UNaV are of prognostic value in nonazotemic cirrhosis with ascites.

Bottled mineral waters polluted by protozoa in Mexico

A survey of protozoa polluting bottled mineral water in Mexico was carried out using samples obtained form the three best-selling brands of bottled mineral water in the country. The organisms were concentrated through filtration procedures and subsequently cultured in the sterile media. The cultures were observed over four weeks, with identification to the level of genus and species. Most commonly found were the amoebae Naegleria gruberi, Acanthamoeba astronyxis, and Vahlkampfia vahlkampfi (trophic as well as cystic stages) plus one flagellate, Bodomorpha minima. No ciliates were detected. The public health importance of the findings is obvious, since some strains of Naegleria and Acanthamoeba have the potential to cause human disease that may lead to death.

[Effect of chronic administration of cimetidine on adenohypophysis secretion in children]

In view of the existing disagreement on the hormonal effects of a chronic treatment with cimetidine, we have studied on a sample of 18 children, the possible alterations that might occur. A comparison has been established between basal conditions and a two-month treatment with 500 mg. a day, on levels of GH, PRL, LH, FSH, TSH and cortisol (as an indirect measurement of ACTH). The statistic study has not shown any noticeable difference in the considered period of time, and dose that has been used does not provoke any alteration in adenohypophyseal secretion.

Oat cell carcinoma of the oesophagus. Case description and review of the literature

The small oat cell type of carcinoma is only rarely seen in extrapulmonary sites. To date, nineteen cases have been described in the oesophagus, almost all by Japanese authors. In this report we review the relevant literature and add one more case of pure type to the total. The histopathological, histochemical and ultrastructural findings and the similarity of this tumour to the oat cell bronchial carcinoma, lead one to propose that it originates in the cells of the APUD series, which have been demonstrated in the normal oesophageal epithelium. Thus is represents on endocrine carcinoma of the oesophagus.

Use of piretanide, a new loop diuretic, in cirrhosis with ascites: relationship between the diuretic response and the plasma aldosterone level

Twenty patients with cirrhosis and ascites but no renal failure were given piretanide, a new loop diuretic, in order to investigate its efficacy and to relate the diuretic response with the pretreatment plasma aldosterone concentration. Eleven patients responded to piretanide 12 mg/day (equivalent in potency to 80 mg furosemide); there was no response in nine patients. Both groups were similar with regard to liver function, plasma urea, serum creatinine, plasma electrolytes, urine volume, and urine potassium concentration. The basal urinary sodium excretion was significantly higher in those patients who responded (23.6 +/- 5.7 mmol/day vs. 4.3 +/- 1.42 mmol/day; P < 0.01) (M +/- SE). Plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were normal or only slightly increased in patients who responded to piretanide (PRA = 1.22 +/- 0.20 ng/ml/h; PAC = 12.25 +/- 2.20 ng/100 ml) and very high in patients who did not respond (PRA = 8.71 +/- 1.18 ng/ml/h; PAC = 84.6 +/- 16.2 ng/100 ml) (P < 0.001). Patients unresponsive to piretanide 12 mg/day also failed to respond when the dose was increased to 24 mg/day. However, the addition of spironolactone, 150 mg/day, to piretanide was followed in these patients by a marked increase in diuresis and natriuresis. These results strongly suggest that the pre-treatment level of aldosterone is an important factor influencing the response to loop diuretics in patients with non-azotaemic cirrhosis and ascites.

The effect of postovulatory administration of dehydrogesterone on plasma progesterone levels

The effect of dehydrogesterone upon corpus luteum function as reflected by plasma progesterone levels was investigated in eight healthy women. No significant difference was found between control cycles and treated cycles when dehydrogesterone, 20 mg daily, was given orally for 10 days after ovulation.

Nonchromaffin paraganglioma of the duodenum

A benign nonchromaffin paraganglioma of the duodenum is described and compared with other reported cases. Duodenal location is extremely rare but the morphology, based on the optical microscopic pattern (Zellballen) and the ultrastructural appearance is, comparable with paragangliomas of other sites. The lack of nerve fibres and ganglion cells in this tumour, together with the absence of a positive chromaffin reaction permits us to classify it as a pure nonchromaffin paraganglioma. This finding constitutes indirect evidence of the probable existence of a paraganglion in the duodenal wall, a structure not yet demonstrated in the adult.

Renin, aldosterone and renal haemodynamics in cirrhosis with ascites

The interrelationships between the renin-angiotensin-aldosterone system, renal haemodynamics and urinary sodium excretion were investigated in fifty-six non-azotaemic cirrhotics with ascites. In twelve additional patients the renal renin secretion rate was also studied. Plasma renin activity and concentration and plasma aldosterone ranged from normal to very high values. There was a significant inverse relationship between plasma aldosterone and the urinary sodium excretion. Plasma aldosterone showed a highly significant direct correlation with plasma renin activity, and plasma renin concentration was closely and directly related to the estimated renin secretion rate. Neither plasma renin activity, plasma renin concnetration nor the estimated renin secretion rate correlated with the renal plasma flow or the glomerular filtration rate. These results suggest that in non-azotaemic cirrhosis with ascites the renin-angiotensin-aldosterone system is an important factor influencing sodium excretion, increased plasma renin and aldosterone concentrations are mainly due to an increased secretion rate, and total renal perfusion is not a major factor influencing renin secretion.

Arterioventricular relations and their classification. Two specimens of arterioventricular discordance and review of published reports

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