Generation of amyloid A protein by the cell lines from amyloid-susceptible and -resistant mice.

It has been proposed that impaired degradation is the cause of amyloid A (AA) formation in reactive amyloidosis (Ham et al., Scand J Immunol 1997; 45: 354-60). The current SDS-PAGE of the culture medium showed that the macrophage cell line from the amyloid-susceptible mouse strain (ANA1) degraded amyloid precursor protein serum amyloid A into the AA-like amyloidogenic product of approximately 8.6 kDa but went no further, whereas cells from the resistant strain (A/J10) cleared the AA-like derivates proceeding to approximately 7.7 kDa products within the incubation period. Degradation occurred in the chemically defined medium at a slower rate than in the medium with serum. This may imply that a lack of the serum components as well as impaired degradation could contribute to the development of amyloidosis.

Effects of oral supplementation with stable strontium.

The biologic effects of stable strontium, a naturally occurring trace element in the diet and the body, have been little investigated. This paper discusses the effects of oral supplementation with stable strontium in laboratory studies and clinical investigations. The extent of intestinal absorption of various doses of orally administered strontium was estimated by determining serum and tissue levels with atomic absorption spectrophotometry. The central observation is that increased oral intake produces a direct increase in serum levels and intracellular uptake of strontium. The results of these studies, as well as those of other investigators, demonstrate that a moderate dosage of stable strontium does not adversely affect the level of calcium either in the serum or in soft tissues. In studies of patients receiving 1 to 1.5 g/d of strontium gluconate, a sustained increase in the serum level of strontium produced a 100-fold increase in the strontium:calcium ratio. In rats, studies indicate that an increase in intracellular strontium content following supplementation may exert a protective effect on mitochondrial structure, probably by means of a stabilizing effect of strontium on membranes. The strontium:calcium ratio in animals receiving a standard diet is higher in the cell than in the extracellular fluid; this may be of physiologic significance.An increase in density that corresponded to the deposition of stable strontium was observed in areas of bone lesions due to metastatic cancer in patients receiving stable strontium supplementation. This suggests the possibility of using strontium to mineralize osteophenic areas and to relieve bone pain. Also, because of reports of an inverse relation between the incidence of dental caries and a high strontium content in drinking water, the use of natural water containing relatively high levels of stable strontium should be considered. In each of these instances it is important to maintain a normal dietary intake of calcium.

Influence of fucoidan on the intestinal absorption of iron, cobalt, manganese and zinc in rats.

Fucoidan was extracted from the seaweed Ascophyllum nodosum with boiling water and purified by repeated precipitation steps. Increasing doses of fucoidan (1.2--200 mg) were injected together with 360 nmol 59Fe-(FeCl3) or 60Co-(CoCl2) into tied-off jejunal segments of two groups of rats fed either a normal (160 mg Fe/kg) or a low iron diet (5 mg/kg). Fucoidan together with 360 nmol 54Mn-(MnCl2) or 65Zn-(ZnCl2) was administered in the same manner in rats fed a normal diet only. Fucoidan administered in doses above 30 mg decreased the absorption of iron, cobalt, manganese and zinc in normal rats, and the absorption of iron and cobalt in iron-deficient rats. This inhibitory effect of fucoidan on the absorption of heavy metals is apparently the consequence of the formation of metal complexes which are poorly absorbed from the intestinal lumen.

Pepsin and acid secretions during and after gastric operations in patients with duodenal ulcer.

Measurement of gastric pepsin and acid secretion was performed before, during and after selective vagotomy with antrectomy (SVA) and Billroth I gastrectomy (B-I) in 20 patients with a duodenal ulcer. Preoperative pepsin concentration increased during operation and decreased gradually 72 hours after SVA and 1 to 3 months after B-I. Although the pepsin concentration decreased substantially, it was never less than 70% of the preoperative level in both groups. Acid concentration decreased immediately after vagotomy in the SVA group and decreased gradually after 72 hours in the B-I group. Although there was a notable increase in the pH in both groups after operation, a pH of 5 was never reached. Decrease in gastric secretory volume (about 50%) was approximately equal in both groups. It appears that any increase in acid secretion occurring after vagotomy or gastrectomy may be sufficient to activate high-and low-pH-acting pepsins. Extravagal and extraantral stimulation of gastric pepsin secretion after operation should be considered an important etiologic factor in the pathogenesis of recurrent ulcer.

Relationship between gastric mucosal pH and site of peptic ulceration.

Measurements of mucosal pH of resected stomachs were carried out in gastric and duodenal ulcer patients. Low mucosal pH along the lesser curvature and relatively higher gastric pepsin levels were found. It is suggested that this lower pH affects gastric ulcer occurrence in the limited "lesser curvature area" where 63 per cent of the ulcers were situated. It is also suggested that increased pepsin activity present in gastric ulcer patients may be another factor affecting gastric ulcer formation by virtue of pepsins activated at higher pH. In duodenal ulcer patients, these factors are "overshadowed" by high acid-pepsin secretory activity of gastric juice.

Effects of the hexahydroxyhexane myoinositol on bone uptake of radiocalcium in rats: Effect of inositol and vitamin D2 on bone uptake of 45Ca in rats.

The objective of this study was to investigate the effects of inositol and vitamin D2 on bone uptake of 45Ca in rats. The radioactive calcium was administered to young rats by orogastric intubation (2 muci/100 g body weight (b. wt)) with inositol (20 mg/100 g b. wt.) and/or vitamin D2 (5OO IU/100 g b. wt.) to normal rats. Bone uptake of 45Ca was measured after 24 hours by standard technique. Inositol alone produced a 48% increase in calcium uptake. It is concluded that inositol significantly increases bone uptake of radioactive calcium (P greater than 0.005). Simultaneous administration of vitamin D2 decreases the effect of inositol considerably, while vitamin D2 has no significant effect.

[Gastric cancer--an attempt to correlate experimental and clinical findings (author's transl)]. / Klinisch-experimentelle Korrelationen beim Magenkarzinom

The correlation of induced gastric cancer in experimental animals with spontaneous gastric cancer in man may be based on several parameters. Malignant tumors have many properties, such as growth, heterotopia, anaplasia, unresponsiveness to extrinsic stimuli, and ability to evoke local and systemic reactions in the autologous host. Individually these properties do not characterise malignancy, but collectively they provide criteria for correlation of human and experimental gastric cancer. Accumulated data, particularly recent findings, attest to many similarities of induced animal and spontaneous human gastric cancer. However, the complexity of the disease is emphasized and data indicate a multi-causative etiology, with various factors interacting in a multi-coordinate manner.

Increased prothrombin time and metabolic changes with high serum aluminum levels following long-term exposure to Bayer-process alumina.

Serum aluminum levels twice to three times those in controls were found in 30 of 36 workers in a factory in an atmosphere of alumina dust. Inorganic phosphate and total alkaline phosphatase levels were within normal range, with no clinical evidence of phosphate depletion syndrome. Serum intestinal alkaline phosphatase, acid phosphatase and adenosine triphosphate levels were significantly reduced in the group with high levels of aluminum. The finding that the mean prothrombin time was significantly prolonged is of particular interest with respect to beneficial antithrombogenic effect.

Studies on natural gastric flora: survival of bacteria in fasting human subjects.

The present report deals with the survival of micro-organisms in the gastric lumen of fasting human subjects. Studies were carried out on hospitalized adult patients during the day, at night and over a 24-hour period.It is concluded that the survival of bacteria in the gastric lumen depends on the pH of the gastric juice. The duration of survival of the organisms at the pH <3.0 varied; however, at pH> 4.0, when a subsequent rapid drop in pH occurred, the clearing of viable organisms occurred within the hour sampling period in most cases. It is possible that medications which decrease gastric acidity favour an increase in the growth of gastric bacteria, while substances with a low pH may decrease bacterial growth.

Studies on inhibition of intestinal absorption of radioactive strontium. IX. Relationship between biological activity and electron microscopic appearance of alginic acid components.

The inhibitory action of alginate on intestinal absorption of radioactive strontium was investigated in order to correlate the biological activity with the chemical composition. Alginate from Laminaria hyperborea was partially hydrolyzed with oxalic acid and the degradation products were fractionated into polymannuronic and polyguluronic acid. The activity of these products was assessed biologically in rats and morphologically by electron microscopy. Sodium polymannuronate was found to be less effective than sodium polyguluronate in preventing absorption of radiostrontium. The inhibition of absorption of radio-calcium was low and not affected by hydrolysis or fractionation. When dried from dilute aqueous solutions, the polymannuronate retained the original helical structure of alginate, while the polyguluronate showed a strong tendency to coagulate, forming granules. The variation in the biological activity was attributed to the morphological differences between these alginic acid components and it is suggested that the degree of uncoiling of the polyguluronate chain in water is greater than that of the polymannuronate chain, thus making the carboxylate ions more accessible to strontium.

Studies on natural gastric flora. I. Bacterial flora of fasting human subjects.

The presence and survival of ingested micro-organisms, both pathogenic and commensal, is of practical interest because the stomach is one of the principal portals of entry of bacteria in humans. A study of the environmental factors governing the survival of indigenous flora in the gastric lumen will assist in determining whether potentially pathogenic organisms will survive in the stomach and pass on. The authors set out to determine the significance of gastric mucin in such survival, with the ultimate objective of learning what factors provide optimal bactericidal conditions.Samples of gastric juice were aspirated from 149 fasting individuals; samples of saliva, nose and throat swabs were also obtained. Positive gastric cultures were found in 82%. The study of the effects of gastric pH demonstrated an increase in the number of samples showing growth above pH 2.0 and a concomitant increase in total bacterial growth. At a pH lower than 2.0, certain organisms are selected out. It appears that even minor changes in gastrointestinal physiology disrupt the normal clearing of the flora.