Search

Within the endometrial cavity intrauterine contraceptive devices (IUDs) become encrusted with cellular, acellular, and fibrillar substances. Scanning electron microscopy was used to study the crust. Cellular material consisted mainly of blood cells and various types of bacteria. The fibrillar material appeared to be fibrin which was omnipresent in the crust and formed a thin layer immediately over the IUD surface. X-ray microanalysis of the acellular component of the crust revealed the presence of calcium. No other major peaks were identified. Near the IUD surface characteristic calcium phosphate crystals were present. Their microanalysis showed peaks for calcium and phosphorus. X-ray diffraction of the crust however, showed it to contain only calcite. It is through the use of scanning electron microscopy that calcium phosphate has been detected in the IUD crust and a fibrillar layer has been visualized on the IUD surface. This study further demonstrates the effectiveness of SEM analytical techniques in the area of biomedical research.

Calcium oxalate nephrolithiasis in rats, induced by single intraperitoneal injection of sodium oxalate, is associated with pathologic changes in the renal papillary tip. Calcium oxalate crystals appear in the tubular lumens, in the intercellular spaces between epithelial cells, and attached to the tubular epithelial basal lamina. Unusual paracrystalline structures also develop in the distal tubule associated with the basal lamina. Speculations are made about the role of these structures. The epithelial changes are primarily necrotic and are similar to those described in experimental papillary necrosis. Complete morphologic recovery occurs in 1-2 weeks.

We have examined whether the addition of powdered rice and pulses (Dal moong) to oral rehydration solution will decrease the purging rate and thereby increase the efficacy of the oral rehydration therapy. The study was carried out on 60 male infants, with acute watery diarrhoea, moderate dehydration but without fever, vomiting, or other conditions like septicaemia and meningitis. The infants were treated with either the standard WHO oral rehydration salt solution (ORS) or with a modified solution where glucose was removed and powdered rice and Dal moong were added. We found that the infants receiving ORS with powdered rice and Dal moong had significantly lower fluid losses in the stools, a significant and more rapid weight gain, and needed significantly less fluid than the infants receiving ORS only.

Tetanic convulsions are not uncommon among severely dehydrated children in the developing countries. This raises the question whether these children have disturbances in the homeostasis of divalent ions. Serum values are reported of calcium, magnesium, phosphorus, sodium and potassium, as well as blood pH in children below 3 years of age with acute watery diarrhoea and with an estimated weight loss of about 10%. The study was performed on dehydrated children with (DC) or without (D) convulsions. Values were obtained on admission and following rehydration therapy (RT). On admission serum calcium was low in both D and DC children. Serum phosphorus was likewise elevated in both D and DC children. Serum magnesium was slightly elevated in the DC but not in the D group. No patient had hypernatremia. During RT, serum calcium increased significantly and serum phosphorus decreased significantly in D and DC children. Serum calcium showed a significant inverse correlation with serum phosphorus and a significant direct correlation with blood pH. Treatment of DC children with i.v. calcium and i.m. magnesium had no immediate effect on the convulsions. Our conclusion is that severely dehydrated children will develop hypocalcemia. The cause may be a redistribution of calcium into the cells, parallelled by a redistribution of phosphorus from the intra- to the extracellular space.

All urinary concretions are composed of a crystalline or mineral phase and a non-crystalline phase. Both phases vary markedly in their chemical nature. There are a number of theories about the role and morphogenesis of the organic phase or matrix. In our opinion, at least a part of the matrix is formed by adsorption of urinary proteins onto crystal surfaces. It has already been shown that naturally occurring polymers have an affinity for calcium oxalate crystal surfaces and that spaces filled with amorphous substances exist between calcium oxalate monohydrate crystals of whewellite renal stones. We wanted to visualize these crystal surfaces with adsorbed organic material. We studied calcium oxalate monohydrate crystals from urinary stones, and crystal made in a crystallizer and incubated in gamma globulin or bovine serum albumin. We also studied calcium oxalate monohydrate crystals experimentally induced in rat renal tubules. They were studied using light, scanning and transmission electron microscopy with, as well as without, EDTA digestion. All crystals were surrounded by an amorphous coat which may have originated by adsorption of proteins on crystal surfaces.

Calcium oxalate monohydrate crystalluria was experimentally induced in male rats by administration of ethylene glycol. The crystalluria particles were separated by filtration and studied by scanning and transmission electron microscopy. They were associated with cellular degradation products. Organic material was present both on the surfaces of crystalluria particles as well as within them and was organized in radial striations and concentric laminations. It is proposed that crystal nuclei were formed by heterogeneous nucleation. These nuclei then adsorbed organic material and aggregated. The organic material polymerized resulting in the formation of a crystal-matrix unit which then grew and incorporated more organic material during the crystal growth.

Urine of male Sprague-Dawley rats was supersaturated for struvite and often contained struvite crystals. Ethylene glycol administration to these rats resulted in elevation of urinary oxalate and calcium oxalate supersaturation, and induced calcium oxalate crystalluria. Implantation of foreign bodies in their urinary bladders and changing their urinary ambient conditions by administering ethylene glycol for two weeks at two week intervals resulted in the formation of urinary stones of mixed composition containing calcium oxalate and struvite. Crystal-onto-crystal epitaxy did not appear to play any role in the development of these stones.

Calcium oxalate crystalluria was induced in laboratory rats by subcutaneous implantation of potassium oxalate containing mini-osmotic pumps in their intercapsular region. Concentrations of major urinary ions were measured and urinary supersaturations of various urinary salts were calculated using a computer programme. The urines of experimental animals that received oxalate had calcium oxalate crystals and higher supersaturations for calcium oxalate compared to their controls. Oxalate levels of the urines of experimental animals were higher than their controls and this increase was proportional to the increase in urinary supersaturation of calcium oxalate. No significant difference was found in the calcium levels of urines from experimental and control animals.

Organic material associated with the calcium oxalate crystals in urinary stones and experimentally induced nephrolithiasis was stained with colloidal iron and analysed by energy dispersive x-ray microanalysis using standard techniques. Iron was positively identified in the stained specimens indicating that some of the organic material is an acidic mucosubstance. The results also indicate that some of the organic material of urinary stones may originate in the kidneys.

Birefringent crystals of calcium oxalate have been previously identified in the colloid of human thyroid glands. We found such crystals in 19/20 adult thyroids at autopsy, in 4/20 infants at autopsy, and, using frozen sections, in 19/20 thyroids partially or totally removed at surgery. These crystals were soluble in hydrochloric acid, insoluble in acetic acid, and contained only calcium by energy dispersive X-ray microanalysis, confirming their calcium oxalate character. Similar crystals were found in equine and ovine thyroids.

Intestinal permeability was assessed with different-sized polyethylene glycols (PEG 400 and PEG 1,000) in small children with acute diarrhea. All children with acute diarrhea absorbed and excreted less PEG of all molecular sizes into the urine when compared with healthy control children (p less than 0.001). Children with acute rotavirus infection excreted significantly less PEG of all sizes than children with Shigella, Salmonella, and enteropathogenic Escherichia coli (EPEC) infection (p less than 0.001-0.01), suggesting a more severe mucosal lesion caused by rotavirus. In patients with severe malnutrition there was also a significant decrease in absorption of PEGs observed. In addition, malnourished patients with rotavirus diarrhea showed a pronounced decrease of PEGs in comparison with well-nourished patients. The ratio between the recovery of a large PEG molecule, 1,074 Da, and a small molecule, 370 Da, was utilized to assess the absorption of large molecules in relation to that of smaller ones. On applying this ratio, it was noted that the intestine in children with Shigella and EPEC infection was relatively more permeable to larger molecules than in healthy controls, while in rotavirus and Salmonella infection it was less permeable to larger molecules. In this study significant differences in the permeability characteristics were observed, suggesting etiology-specific effects on the mucosal barrier.

A procedure for studying urinary stones by various microscopic techniques is described. The stones are sectioned into approximately 0.2 to 1.0 mm. thick pieces using a low-speed saw. The sections are then embedded in agar and decalcified using 0.25 M ethylenediaminetetracetic acid at pH 7.2. The decalcified residue is then processed for light microscopy and scanning and transmission electron microscopy as with any other biological tissue. The results indicate that the ethylenediaminetetracetic acid-insoluble stone matrix keeps its architectural integrity and can be studied like other biological materials.

We report the case of a white woman with bilateral renal calculi that were removed by bilateral nephrolithotomies. The morphology of renal tubular stones and the changes in papillary tissue were studied by light microscopy and scanning and transmission electron microscopy. The stones were made of calcium oxalate and were intratubular. Large calcium phosphate deposits were present in the interstitium. There was a marked interstitial fibrosis and tubular epithelial hyperplasia.

Twenty insulin-dependent diabetic teenagers from the Oxford pediatric diabetic clinic were recruited to study the relationship between diabetic control and retinal microvascular disease. Two patients (10%) had evidence of minimal background diabetic retinopathy on careful ophthalmoscopy. Retinal color photography and fluorescein angiography each revealed retinopathy in 5 patients (25%) and together revealed retinopathy in 7 patients (35%). Color photography demonstrated retinopathy which had not been discovered on ophthalmoscopy. The presence of retinopathy was related to the duration of diabetes (p less than 0.02) and the glycosylated hemoglobin level (p less than 0.01). It is concluded that multiple field color photography is a useful method of assessing patients with minimal or no ophthalmoscopic retinopathy.

We have compiled a broad overview of the genesis of urinary stones. Central to the theses given are precise definitions of stone as opposed to stone disease. In terms of mechanisms, a kinetic point of view is essential to any formulation relating to stone formation. It is necessary to comprehend the kinetic approach, an understanding of nucleation, growth and aggregation, if one is to appreciate the final product--the stone. Certain fundamental concepts are reviewed which are critical in grasping these phenomena. Not to be forgotten is that the purely physical chemical aspects of stone formation are insufficient to explain all facets of the process. Therefore, interactions between crystals and tissue are explored in suggesting a unifying hypothesis for upper tract stone disease.

Intestinal hypomotility is a common late complication in infants with acute diarrhoeal disease in pakistan. Among the infants admitted to our gastrointestinal unit with a history of acute diarrhoea, 35% developed abdominal distension and 12% developed the full clinical picture of paralytic ileus. The infants with ileus were treated with decompression and total parenteral nutrition; in this group the mortality rate was 25%. We compared 30 infants who developed ileus (group A) with an age-matched control group of infants (group B) who were admitted because of acute diarrhoea but did not develope ileus. The use of antimotility drugs was significantly more frequent in group A. Serum-K was not different in in group A (3.92 +/- 0.22 mmol/l) and group B (4.32 +/- 0.18 mmol/1). However, there were more patients who had serum-K below 3 mmol/l in group A (8/30) than in group B (5/30). We conclude that the use of antimotility drugs predisposes to the development of ileus in infants with acute diarrhoea. Hypokalemia may contribute to ileus in a few cases but is generally not a prerequisite.

Crystalluria was induced in male Sprague-Dawley rats by implanting potassium-oxalate-containing mini-osmotic pumps. Urine of all experimental animals had abundant crystals of calcium oxalate, hydroxypatite, struvite, and calcium phosphate. These crystals were similar in morphology to the crystals found in human crystalluria. Histological examination of kidneys and tissue samples from other organs revealed no abnormality. One group of animals was injected with sodium oxalate in addition to implantation of potassium-oxalate-containing mini-osmotic pumps. Bladder urine from these animals contained calcium oxalate microstones and their kidneys had deposits of calcium oxalate crystals.

The formation of calcium oxalate crystals in rat kidneys was induced by intraperitoneal challenge with sodium oxalate. The structure of these crystals and the effect of their formation on the architecture of the tubular epithelium was studied by SEM. From the results we conclude that the crystals were formed intraluminally in the renal tubules. During the growth of the microliths they were closely adherent to the luminal surface of the tubular epithelial cells. Two types of the crystals were identified. Calcium oxalate monohydrate crystals consisted of plate-like crystallites and were more common. Dihydrate crystals on the other hand were tetragonal dipyramids and were less common. Elemental analysis of the crystal surface revealed them to be closely similar to the crystals present in calcium oxalate stones. The renal tubules were morphologically altered. Their epithelial cells underwent focal necrosis. There was a focal loss of the microvillous brush border of the proximal tubules. The epithelial cells formed large blebs which protruded into the tubular lumen. Sometimes the tubular lumen was completely occluded by the crystals. Crystals were often covered with cellular debris. It is suggested that the cellular debris derived from from necrotic cells become incorporated into the calculi. A similar process may be involved in the formation of mucoproteinaceus matrix of the human renal stones.

Organic matrix of human calcium oxalate urinary stones was obtained by demineralizing with EDTA. Lipids were extracted from the EDTA-insoluble matrix by chloroform methanol treatment. The whole matrix and its total lipid extract were then incubated in a metastable solution of calcium oxalate and depletion of calcium and oxalate ions from the calcifying solution was determined. Results of our studies described here show that urinary calcium oxalate stone matrix and its total lipid contents were capable of binding calcium and oxalate ions and of catalysing calcium oxalate crystal formation from a metastable calcium oxalate solution.

The early phases of calcium oxalate crystal formation in rat kidneys after intraperitoneal challenge with sodium oxalate were examined. From the results we conclude that the crystals are formed intraluminally in the proximal tubules of the renal cortex. The size, number, and distribution of calcium oxalate particles depend on the amount of sodium oxalate injected and the time interval after its injection. Tubular necrosis and dilation were evident after administration of higher doses of sodium oxalate. The papillary tip and corticomedullary junction were the preferential sites for crystal localization after longer periods of injections of higher doses of sodium oxalate.

Calcium oxalate stone disease is the most common human urinary stone disease in the Western Hemisphere. To understand different aspects of the disease, calcium oxalate urolithiasis in the rat is used as a model. Spontaneous calcium oxalate urolithiasis is very rare in rats. Thus the disease is experimentally induced and the rats are generally made hyperoxaluric either by administration of excess oxalate, exposure to the toxin ethylene glycol, or various nutritional manipulations. All the experimental models show renal injury associated with crystal deposition. Calcium oxalate crystals are in most cases intraluminal in renal tubules and often attached to the basal lamina of the denuded epithelium. Rat renal papillary tips and fornices appear to be the preferential sites for the deposition of large calcium oxalate calculi. Where urinary supersaturation of calcium oxalate has been studied the crystal forming rat urines are shown to have higher urinary supersaturation of calcium oxalate than their controls. Oxalate metabolism in the rat is nearly identical to that in humans. Thus, in a number of respects, experimental calcium oxalate urolithiasis in the rat is similar to calcium oxalate stone disease in man.

Experiments to evaluate the neurochemical action of gaseous pollutants were performed in a specifically designed inhalation chamber. Exposure of guinea pigs to 10 ppm of SO2 for one hour daily for 21 days produced a significant depletion of total lipids and free fatty acids in all brain regions. Phospholipid and cholesterol content of the cerebellum and brain stem were also decreased, but were increased in cerebral hemisphere. Esterified fatty acids were depleted in the cerebral hemisphere and brain stem, but exhibited increment in the cerebellum. The rate of lipid peroxidation and the activity of lipase were increased significantly in all the regions of the brain. The results clearly indicate that SO2-exposure induces degradation of brain lipids. Interestingly, the lipid contents are affected differentially in the various parts of the brain.

The influence on secretory IgA antibody levels in milk and saliva of vaccination with oral, live poliovirus vaccine ( OPV ) and inactivated poliovirus vaccine (IPV) was studied. IPV, especially the antigen-rich Dutch vaccine, more often induced increases in antibody titers in milk (50%) than did OPV (26%) (P less than .01). OPV more often decreased the antibody levels in milk (40%) than did IPV (10%) (P less than .01). It was striking that mainly high prevaccination titers were decreased. The increases of IgA antibody in saliva were less striking. IPV caused increases as often in milk as in saliva, whereas OPV more often induced increases in IgA antibody in saliva, but there was a poor correlation between the changes in antibody titers in milk and those in saliva.

Calcium oxalate bladder stones were induced in male rats by implanting plastic foreign bodies and by adding ethylene glycol to their drinking water. The foreign body surface was first coated with cellular debris and some amorphous material. Encrustation with crystals of calcium oxalate started on the third day of implantation. Within 2 weeks the entire surface of a foreign body was covered with crystals and some noncrystalline material. Calcium oxalate monohydrate crystals consisted of platelike crystallites arranged in hemispherulitic or spherulitic habit. Calcium oxalate dihydrate crystals wee basically dipyramidal, a majority of them showing interpenetrant twinning. The stone grew by confluent crystal growth and crystal aggregation. A transformation of calcium oxalate monohydrate crystals to calcium oxalate dihydrate also occurred. The matrix consisting of cellular debris and urinary macromolecules was universally distributed in the stone including the inside of crystal bodies.