Search

Tartrate-resistant acid phosphatase activity (TRAPase) is widely used as a cytochemical marker to distinguish osteoclasts from macrophages and other related cell types. The degree of tartrate resistance, however, may depend on which reaction methods, tissues, or species are used. To investigate this further, we have measured the amount of cytochemical reaction product by microdensitometry. We compared osteoclast acid phosphatase (APase) activity in fresh frozen sections of neonatal rat calvaria using two different reaction methods; one is commonly employed for qualitative histochemistry and includes alpha naphthyl phosphate as substrate, simultaneous coupling to the chromagen Fast Garnet, and a 30-minute reaction time (method A). The other may be used to measure enzyme reaction rates in cells in situ and employs conditions suitable for initial velocity kinetics, namely naphthol-ASBI phosphate as substrate, post coupling to Fast Garnet, and a 2-minute reaction time. Although enzyme reaction rates differed greatly between the two methods, significant inhibition of APase activity by tartrate was observed in calvarial osteoclasts (69% and 59% with methods A and B, respectively), osteoblasts, and spleen macrophages. Using method B, mouse calvarial osteoclasts had similar APase activity to that seen in the rat. Tartrate produced little inhibition in these mouse cells, in contrast to the observations made with rat tissue, but murine spleen macrophages were significantly tartrate sensitive (40% inhibition with tartrate). On this basis, conclusions regarding the cell specificity of TRAPase should be treated cautiously.

A 40-year-old man with hepatitis B surface (HBs) antigenemia developed the nephrotic syndrome. Renal biopsy revealed a glomerulonephritis with features of both membranous glomerulonephropathy and IgA nephropathy. Histologically some glomeruli showed mesangial expansion and hypercellularity only, while others contained sclerotic segments. Direct immunofluorescence demonstrated granular IgG-bearing deposits along the peripheral glomerular capillaries and IgA-containing ones in the mesangium. HBs antigen was detected by indirect immunofluorescence both along the glomerular capillary walls and within the mesangium. Granular epimembranous and mesangial deposits were observed by electron microscopy. A few mesangial deposits consisted of spherical particles, 35-100 nm in diameter. Although 3 cases of mixed membranous and IgA nephropathy have been previously reported, this appears to be the first one to be associated with HBs antigenemia.

The in vitro stability and immunointegrity of four radioiodinated monoclonal antibodies was evaluated in various storage conditions and also in plasma samples. The monoclonal antibodies studied included T101, B72.3, Lym1, and 16.88. Stabilities of typical monoclonal antibody therapy solutions, with radioactivities ranging from 2220 to 3700 MBq (60-100 mCi) were assessed using conventional instant thin layer chromatography and size exclusion high performance liquid chromatography. Radioimmunoreactivity was assessed using a live cell attenuated cell, or mucin-linked bead assay. Results of the study demonstrated that therapy solutions were stable to degradation, if properly stored in 5 or 10% human serum albumin at 4 degrees C for the duration of the study (5 days). Minor losses in immunoreactivity were also measured in stabilized therapy solutions. When incubated in plasma samples, radioiodinated monoclonal antibodies generally remained stable for the duration of the study (3 days). However, significant decreases in immunoreactivity were measured for specific radioiodinated monoclonal antibody preparations.

1. Gastric emptying, gastric acid and pepsinogen secretion were assessed simultaneously in the conscious calf using the test meal and duodenal perfusion technique (Bell & Mostaghni, 1975).2. Duodenal infusion of NaCl at a constant osmolality of 300 m-osmole/kg, but with pH ranging from 2.0 to 12.0, did not alter the high level of gastric emptying and secretion already reported for isotonic NaCl or NaHCO(3) alone (Bell & Mostaghni, 1975; Bell & Webber, 1979). Gastric function, therefore, is either unaffected by gastric chyme at pH 2.0-12.0 entering the duodenum, or else isotonicity is dominant over pH in activating duodenal receptors which increase motor activity.3. When the pH of the isotonic NaCl was reduced by the addition of HCl to below pH 2.0, inhibition of gastric function occurred in direct proportion to the amount of titratable acid present in the infusate. The H(+) moiety of isotonic duodenal infusates of pH < 2.0 dominates activation of osmoreceptors and so inhibits motor activity.4. When the same amount of acid but at differing concentrations and infusion rates was introduced into the duodenum uniform inhibition of gastric function occurred. This result indicates that duodenal acid receptors respond to acid concentration and flow rate to produce an integrated response in proportion to the amount (concentration x volume) of acid present.5. Isotonic NaHCO(3) solutions adjusted to pH 8.1-12.0 by the addition of NaOH, like isotonic NaCl infusions, did not affect gastric function until pH 11.0-12.0, when significant inhibition occurred. This inhibitory effect of isotonic NaHCO(3) at high pH is probably due to CO(3) (2-), since Na(2)CO(3) and Li(2)CO(3), but not LiCl, produce a similar inhibitory effect on gastric function.6. The inhibitory effect of carbonate gives some support to the existence of a CO(2)-sensor as suggested by Hunt & Knox (1972), whereby increased P(CO2) produced by intracellular or intercellular neutralization of CO(3) (2-) by duodenal H(+) activates acid receptors. But other experiments reported here, where simultaneous perfusion of HCl and excess NaHCO(3) produced a rise in intraluminal P(CO2), did not inhibit gastric function, which is contrary to the idea of a direct intraluminal effect of CO(2) on duodenal receptors.7. The pH, P(O2), P(CO2), HCO(3) (-) and base excess of venous blood showed no detectable change during duodenal infusion of either acidic or alkaline solutions. Metabolic acidosis or alkalosis, therefore, cannot be considered to play any part in controlling gastric function. The results thus corroborate the notion that the receptors controlling gastric function are localized in the intestinal mucosa.8. Our results suggest that interplay between acid and osmolality of gastric chyme occurs in the rostral part of the duodenum to produce a graded inhibitory effect which by negative feedback modulates the gastric effectors that normally activate smooth muscle, parietal cells and zymogen cells.

The level of hypoglycaemia required to elicit gastric secretion of acid and pepsin was studied in urethane-anaesthetized rats. Hypoglycaemia was induced by intravenous injection of insulin or by electrical stimulation of the posterior hypothalamus. In each case the blood glucose values below which gastric secretion was stimulated were significantly higher for pepsin than for acid secretion. This consistently resulted in the onset of pepsin secretion in advance of the onset of acid secretion. These observations suggest that the production of the different components of the gastric juice was under the influence of either separate hypothalamic glucoreceptors, or a single set of glucoreceptors able to respond selectively to different blood glucose levels.

Acid phosphatase activity is prominent in osteoclasts (bone resorbing cells) and has been implicated in the process of bone resorption, although its precise role is not understood. To study the distribution and activity of this enzyme, a quantitative cytochemical method has been developed using undecalcified fresh frozen sections of foetal rat calvariae. Sections were allowed to react with 3 mM naphthol ASBI phosphate at pH 5.0, and the reaction was stopped by rinsing in ice-cold tap water containing 50 mM sodium fluoride. The reaction product was post-coupled to Fast Garnet at 4 degrees C. The absorbance of areas of reaction product in the cytoplasm was measured using scanning and integrating microdensitometry. The initial velocity rate was maintained for up to 2 min at pH 5.0 with a substrate concentration of 3 mM and a section thickness of 5 micron. Under these conditions reaction product was localized to osteoclasts and the surface of bone matrix beneath these cells. Activities in osteoblasts and chondrocytes were negligible. Osteoclastic acid phosphatase was almost totally inhibited by 10 mM fluoride and reduced by 70% by 100 mM tartrate.

Perfusion of the stomach in the anaesthetized rat with saline acidified to pH 2.5 with hydrochloric acid induced a small but significant release of pepsinogen into the perfusate. This stimulus to secretion was unaffected by splanchnectomy but was abolished by vagotomy. It is concluded that a modest degree acid secretion in the rat may stimulate pepsinogen secretion by a vagal pathway.

1. The relative importance of energy content and osmolality of the duodenal chyme in the feed-back control of gastric emptying was investigated in the milk-fed calf fitted with gastric (abomasal) and duodenal re-entrant cannulae. 2. Duodenal infusion of isosmolal solutions, containing glucose, fructose or galactose, with a range of combustible energy content (0--1.46 MJ/l.) resulted in the same high rate of emptying of test meals from the stomach (abomasum). Abomasal emptying was, therefore, not affected by the energy content of the duodenal infusate. 3. Gastric secretion of acid and pepsinogen, and the volume of gastric secretions produced were also unaffected by the energy content of isosomolal duodenal infusates. 4. The results of the study show that the combustible energy content of the intestinal chyme is not a direct determinant of gastric function and that total osmolality of the lumenal contents is the only parameter influencing duodenal receptors under the conditions of our experiments.

Levels of endogenous somatostatin, gastric inhibitory polypeptide (GIP), glucagon and insulin were measured during gastric (abomasal) emptying in the conscious calf. Isotonic NaHCO3 infused into the duodenum increased rates of emptying of a saline test meal and of gastric acid secretion, but had no effect on basal levels of blood glucose, somatostatin, GIP, insulin or glucagon. By contrast, intraduodenal infusion of 60 mM-HCl caused complete inhibition of gastric emptying, reduction of acid secretion, and an immediate increase in plasma somatostatin from 121.3 +/- 9.4 (S.E.M.) to 286.3 +/- 16.3 pg/ml (P less 0.01) but levels of GIP, insulin, glucagon and glucose were unaltered. Intravenous injection of somatostatin (0.5 microgram/kg) suppressed the antral electromyographic recording and gastri efflux so long as plasma somatostatin levels remained above approx. 200pg/ml. This suggest that somatostatin can be released by intraduodenal acidification and that it inhibits gastric function by an endocrine effect. Since somatostatin retards gastric emptying it may therefore have an indirect role in nutrient homeostasis by limiting discharge of gastric chyme to the duodenum.

1. Gastric emptying, gastric acid and pepsinogen secretion were assessed simultaneously in the conscious calf using the test meal and duodenal perfusion technique (Bell & Mostaghni, 1975).2. When 60 mM-HCl was infused into the duodenum, gastric emptying was arrested but both acid and pepsinogen secretion continued at a low level. Duodenal infusion with isotonic NaHCO(3) caused rapid exponential emptying of the test meal and acid and pepsinogen output was more than doubled.3. Duodenal infusion of amino acids in isotonic NaHCO(3) did not affect the rapid emptying, except infusion with tryptophan, which caused a measureable degree of inhibition of emptying, with concomitant effects on acid and pepsinogen secretion4. Tryptamine and 5-hydroxytryptamine (5-HT) incorporated in low concentration into isotonic NaHCO(3) also produced depression of gastric emptying, acid and pepsinogen levels comparable to the response initiated by acid infusate. Tryptophan was effective only in non-physiological amounts while 5-HT and tryptamine were active in smaller doses.5. Our results suggest that the inhibition of gastric emptying following duodenal infusion of tryptophan noted by Stephens, Woolson & Cooke (1975) may be due to the duodenal synthesis of its biogenic amine derivatives tryptamine and 5-HT.6. The level of activity of the three gastric functions, emptying, acid secretion and pepsinogen secretion appears to be linked. A single stimulus, therefore, could evoke a duodenal receptor or receptors to mediate or suppress activity of the gastric smooth muscle and secretory cells through interrelated mechanisms. The effect of some duodenal infusates, however, produces some variability in response which suggests differential activation of different receptors with consequent variable motor activity on effector cells.

The authors used immunohistochemical staining for S-100 protein to search for Langerhans cells in 7 cases of pulmonary eosinophilic granuloma (EGL) and in 18 cases of other pulmonary processes (including reactive eosinophilic pleuritis, chronic interstitial pneumonias, eosinophilic pneumonia, and nonspecific scars), which can produce diagnostic confusion with EGL. Qualitatively, Langerhans cells were found in almost every disease. However, cases of active or resolving EGL showed greater than 75 such cells/10 high-power fields (hpf), often appearing as densely packed aggregates (a virtually diagnostic feature), while all other conditions, including completely scarred EGL, showed fewer than 35 Langerhans cells/10 hpf, and the cells were scattered through the parenchyma. The authors conclude the following: (1) Langerhans cells participate in many types of inflammatory process in the lung, and hence the mere presence of Langerhans cells is not diagnostic of EGL; (2) S-100 staining with quantitation of Langerhans cells is a useful adjunct in the diagnosis of active and resolving EGL.

In brief: A review of the records of 62 runners treated for stress fractures showed that initial x-rays were positive in 47.2% of the cases, while bone scans were positive in 95.8%. A combination of errors in training and changes in footwear accounted for 44% of the fractures, and all the patients had alignment problems. The runners had waited until their performance was seriously impaired to seek treatment. The authors concluded that if point tenderness and soft-tissue swelling are recognized early, stress fractures can be prevented with rest, muscle rehabilitation, and orthotic control of excessive pronation.