Human Calculi Research Articles

PERCUTANEOUS RENAL STONE EXTRACTION: IN VITRO STUDY OF RETRIEVAL DEVICES

Traditionally, percutaneous stone extraction has relied on the use of 2-prong and 3-prong graspers, which are prone to causing trauma to the urothelium. We evaluate the efficiency of stone removal with a novel tipless stone basket designed specifically for percutaneous procedures. A 3, 5 and 8 mm human calculus were placed in the calix of a percutaneous renal model. A 26Fr Storz nephroscope (27093B, Storz Medical AG, Kreuzlingen, Switzerland) was inserted through a 30Fr Amplatz sheath into the model with camera input from a Storz telecam SL-NTSC feeding to a 20-inch Sony Triniton monitor (Sony Corp of America, New York, New York). Operators were randomized to start stone extraction with a Storz 3-prong grasper (27090RB) or a Cook 12Fr Perc-NCircle (38 cm) (Cook Urological, Inc., Indianapolis, Indiana). Subsequent testing alternated between the 2 devices until 10 extraction attempts were conducted with each device. Time to extraction of all 3 calculi and number of inadvertent withdrawals of the sheath were recorded. Three experienced operators tested each device. Stone extraction times were shorter with the Cook Perc-NCircle than the 3-prong grasper for all operators. Mean time for stone extraction was 25.3 +/- 11.2 seconds for the Perc-NCircle compared to 35.1 +/- 18.5 seconds for the 3-prong grasper (p = 0.016). Loss of access by inadvertent removal of the Amplatz sheath occurred in 53% of the attempts with the 3-prong grasper compared to 7% of attempts with the Perc-NCircle. The Cook Perc-NCircle facilitates a more expeditious approach to percutaneous stone removal with less risk of sheath withdrawal.

Determination of cholesterol in human biliary calculus by TLC scanning

Determination of cholesterol in human biliary calculus by TLC scanning

Role of bacteria in the development of kidney stones.

Currently, only struvite stones are regarded as deriving from bacteria. Recent work has suggested that calcium-based stones might also have an infectious origin. Nanobacteria, small intracellular bacteria found in human kidney stones, are capable of forming a calcium phosphate shell, and thus could serve as crystallization centres for renal calculi formation. Until now, however, all trials performed to confirm the presence of nanobacteria in human calculi, serum or urine have failed. In a hyperoxaluric rat model, tissue-residing macrophages were able to remove interstitial crystals and thus may not be primarily engaged in defending against micro-organisms, if present.

In VitroModels for Studying Renal Stone Formation: A Clear Alternative

This paper discusses the limitations of using laboratory animals for direct in vivo observation of the development of renal stones. In fact, the majority of hypotheses related to mechanisms of stone formation have been based on the results of in vitro experiments. The relevance of in vitro experiments that allow the study of urolithiasis depends upon the degree of correspondence between the experimental conditions and those prevailing in the stone-forming kidney in vivo. For this reason, several in vitro experimental systems that attempt to reproduce the conditions found in vivo have been developed in order to study renal stone formation, which have been classified into two main groups: a) models to study papillary stone formation; and b) models to study "sedimentary" stone formation. These models are briefly described in this paper, and the information obtained was compared with that resulting from a study of the fine structure of real human renal calculi, in order to prove the validity of the models. It was concluded that the experimental in vitro models can closely reproduce the renal conditions under which human calculi are developed. This allows important data to be obtained about the aetiology of renal lithiasis, which is of great relevance to the development of effective treatments for this disease. Therefore, experimental in vitro models constitute a clear alternative to the use of laboratory animals.

Inhibition of Formation of Calcium Phosphate Deposits on Teeth and Dental Materials: Recent Advances

The inorganic composition of dental calculi from teeth and dentures has been characterized by x-ray diffraction, electron microprobe, and infrared absorption spectroscopy. They consist of carbonated hydroxylapatite (CHA), dicalcium phosphate dihydrate (DCPD), octacalcium phosphate (OCP), and magnesium-substituted beta-tricalcium phosphate (6-TCMP). The calculi on denture surfaces are principally CHA. Formulations have been developed to inhibit formation of these calculi in humans. The active inhibitors are pyrophosphate, pyrophosphate plus polymer, and zinc salts. These agents inhibit calculus formation in humans by preventing the formation of hydroxyapatite crystals. The new formulations include multiple-benefits products containing fluoride and antimicrobial and/or desensitizing agents. These provide not only reduction in calculus formation in humans but also reduced plaque, gingivitis, and/or dentinal hypersensitivity. Recent studies have also indicated a relationship between gingival recession and supragingival calculus in the Thai population, and the use of an anticalculus formulation has shown significant improvement in gingival recession in this population.

Intraoperative bile duct sonography during laparoscopic cholecystectomy: experience with a 12.5-MHz catheter-based US probe.

During elective laparoscopic cholecystectomy, 20 patients underwent intraoperative evaluation of the biliary tract with a commercial 6.2-F, 12.5-MHz catheter-based ultrasound (US) probe. The study tested the feasibility of this technology for mapping the anatomy of the hepatoduodenal ligament and Calot triangle, assessing bile duct integrity, and detecting choledocholithiasis. The duct was studied with a transmural approach, the catheter being placed parallel to, but remaining outside, the bile duct. The common hepatic duct and common bile duct in the vicinity of the cystic duct were seen in all 20 patients; the junction of the cystic duct with the common hepatic duct was seen in nine patients (45%). After the cystic duct was clamped, no sonographic evidence to suggest bile duct injury was noted in any patient. The transmural imaging approach was tested in four pigs in whose common bile duct a single human calculus had been placed. In all instances the size and location of the calculus were accurately detected. Intraoperative US with a catheter-based system is a safe and effective means for interrogation of the extrahepatic biliary tree during laparoscopic cholecystectomy.

N-terminal sequence extension in the glycosylated forms of human pancreatic stone protein. The 5-oxoproline N-terminal chain is O-glycosylated on the 5th amino acid residue

The pancreatic stone protein isolated from human calculi (PSP) derives from the immunoreactive protein forms detected in human pancreatic juice (PSP S2-5) through the tryptic cleavage of the Arg-11-Ile-12 bond. Among the eleven amino acids of the PSP S2-5 N-terminal extension Z-E-A-Q-T-E-L-P-Q-A-R, the first residue is an oxoprotine and the fifth, a threonine, bears the single carbohydrate chain of the protein molecules. Variations in the glycan chain composition account for the differences in the M r of PSP S2-5. The PSP S2-5 forms are very soluble in aqueous solutions between the pH values 5.0–9.0, whereas the proteolysated form is scarcely soluble.

Formation of bobierrite (magnesium phosphate) crystal aggregates by bacteria from human urine and renal calculi.

The formation of extracellular crystal aggregates of bobierrite [Mg3(PO4)2.8H2O] by bacteria isolated from renal calculi and urine of urolithiasic patients is found with the use of B-17 and B-43 media. The crystal aggregates were observed in the colonies as deposits of brown-yellow coloration, and were identified by X-ray powder diffraction, chemical analysis and scanning electron microscopy. The production of bobierrite by bacteria from human urine and renal calculi implies further versatility of crystal formation by microorganisms, and it may be interesting to investigate the possible relationships between calculi precipitation and urinary infection.

Determination of cadmium, copper, zinc, and lead in human renal calculi in both cadmium polluted and non-polluted areas.

A number of investigators have reported about heavy metal contents in food, blood, urine, and animal tissues, including bone, hair, feather, and tooth. However, few data concerning calculi are reported as yet. Heavy metal contents in the calculi might reflect the level of metals absorbed from respiratory tract, skin and intestine. When absorbed metals from respiration are distributed in blood, a part of cadmium is accumulated in liver and kidney, and of lead is in bone, annular vessel and kidney. The remainder is excreted in the urine through the urinary tracts. From intestine, they are distributed by the blood to the liver, and excreted in the urine in the same manner of respiration. It is well known that renal calculi are produced in the urinary tract. The present study is focused on the contents of cadmium, copper, zinc and lead in human renal calculi, samples collected from Hokuriku which is one of the most cadmium polluted areas and from Chugoku which is recognized as a non-polluted one in Japan.

Percutaneous Nephrolithgtripsy: A Functional and Morphological Study

Percutaneous removal of renal calculi requires a nephrostomy track, irrigation and lithotripsy The purpose of this study is to investigate the effects of these procedures on renal function and anatomy.Renal access was obtained through a small left subcostal incision and a 22 Ch nephrostomy track was formed by fine parenchymal puncture and serial dilation in 15 dogs. Three liters of glycine solution were perfused through these tracks. In a further 16 dogs, human calculi were placed transparenchymally in the renal pelvis and disintegrated under vision through the Wolf nephroscope using an ultrasonic probe in8and electrohydraulic probe in 8. Assessments were made in all animals at 48 hours or 6 weeks by creatinine clearance, microfil casts, contrast radiography and ex-situ conventional and digital subtraction angiography.There was no significant urinary leakage or bleeding from the nephrostomy track at 48 hours. There was a small track hematoma and at 6 weeks a surface dimple and fine linear parenchymal scar. There was no ureteric or pelvic damage. Microfil casts showed small track defects at 48 hours resolving to a fine scar at 6 weeks. All angiograms were normal. Some IVtPs displayed minor track defects at 48 hours but all were normal at 6 weeks. Corrosion casts and subtraction angiography demonstrated no significant vascular defects. Creatinine clearance showed no significant difference between experimental and control sides. Occasionally, intra pelvic scatter of fine calculus fragments was seen at 48 hours but none was detectable at 6 weeks.Transparenchymal nephrostomy, irrigation and nephrolithotripsy caused initial minor anatomical defects that rapidly resolved and were not associated with any loss of renal function.

A canine model for the investigation of human calculus disease.

The rapid development of new methods for the treatment of renal calculi requires an animal model to assess the efficacy of stone treatment in vivo. This requires the implantation of human calculi large enough to be easily imaged radiologically. Most previous models have required multiple operative procedures and ureteric obstruction which has confused results. This study demonstrates the one-stage insertion of human calculi into the canine renal pelvis through a nephrostomy which does not affect the collecting system or cause any significant functional or structural damage to the kidney.

Copper in human subgingival calculus.

The Cu concentration as well as the Ca, Mg, Fe, Pb, Zn, and F concentrations were determined in subgingival calculus and the relation of Cu to Zn, Ca, Mg and Fe described. Samples of human subgingival calculus of 60 pieces from 60 subjects were ashed in an acid solution and the cation concentrations were determined with atomic absorption spectrophotometry. The F content was analyzed with an ion-selective electrode. The data was analyzed using the multiple linear regression analysis. The mean +/-SD of the Cu concentration in the subgingival calculus was 48.4+/-59.0 micrograms/g. Four elements, Zn, Ca, Fe and Mg, explained 41.1% of the Cu content. Zn explained 25.5% and the correlation was positive, whereas Ca (10.4%) had a negative correlation with the Cu content. The results showed such a high Cu content that it could affect the mineralization of calculus.

Light- and electrondashmicroscopic study of the microbial deposits present on the tongue and dentition of macropods

The dental deposits in the kangaroos and wallabies were similar to human calculus with lysed bacterial cell remnants embedded in previously mineralized areas. The surface of the microbial deposits in contact with the enamel showed: (a) triangular structures 3–5 μm deep and 4–5 μm wide at their base repeating every 4 or 5 μm which probably occupied the remnants of Tomes processes which in macropods do not flatten out; (b) irregular, short (1 μm) projections that probably occupied the inter-prismatic areas. Few organisms were observed on the anterior or dorsal surfaces of the tongues but on the posterior region there was abundant microbial colonization. Large amounts of extracellular matrix were preserved using a fixation technique designed to minimize the loss of water-soluble material. Bacteria were arranged perpendicular to the epithelial cell surfaces and were present on either surface of desquamating epithelial cells. Aqueous fixation erroneously suggested that inter-bacterial and bacterial-epithelial cell adhesion was primarily by fine fibrillar strands.

Zn concentration of human subgingival calculus related to F, Mg and Cu contents.

F and Zn content of human subgingival calculus was studied with respect to its Ca, Mg, Cu, Fe and Ph contents. The material consisted of 60 subgingival calculus samples from 60 persons. The element concentrations were determined with an atomic absorption spectrophotometer except for the F content, which was measured with an ion-selective electrode. The data were analyzed using the multiple linear regression analysis. 24% of F content was explained by Zn and none of the other elements were significantly related to F content. Altogether, 55.4% of Zn content was accounted for in all variables. The selected variables after the removal of nonsignificant ones explained 54.8%. The most important variable was F (24.0%) and the explanation power of Cu was 18.3% and of Mg 12.5%. The regression coefficients of these variables were positive. The mean +/- s.d. concentration of F in the samples was 221.2 +/- 174.1 micrograms/g and of Zn 498.6 +/- 499.1 micrograms/g, respectively.

A microbiological study of dental calculus. IV. An electron microscopic study of in vitro calcified microorganisms.

Cultures of microorganisms isolated from human calculus have been calcified using a simple in vitro system. All strains had previously produced hydroxyapatite (HAp) under similar experimental conditions.Ultra‐thin sections of specimens embedded in Epon 812 were examined, with a Philips 200 electron microscope, unstained or double‐stained with uranyl acetate and lead citrate.Intracellular crystals of HAp were seen in all strains examined. The majority of Grampositive rods produced only intracellular calcification, usually mesosome associated and extracellular vesicles were rarely seen. In contrast Gram‐negative rods produced extracellular material—vesicles and debris from disrupted cells—which was heavily mineralized. The association of initial intracellular calcification with mesosomes was not always observed.Extracellular calcification was also a feature of some Gram‐positive and all Gram‐negative cocci with cell‐associated deposits apparently originating from the cell wall. A feature of some species, particularly the Gram‐negative cocci, was the presence of randomly arranged spherules of amorphous calcium phosphate within the cytoplasm some of which appeared to be partially converted to HAp. In the majority of microorganisms examined early mineralization was apparently crystalline.It is suggested that extracellular mineralization of Gram‐negative microorganisms may be a significant factor in early matrix calcification in natural calculus.

The Crystalline Components of Dental Calculi: Human vs. Dog

Dental calculus from the dog was found to consist principally of the calcite form of calcium carbonate mixed with small amounts of apatite; other calcium phosphates, consistently present in human calculus, were not present in dog calculus. Precipitable calcium salts from human saliva were mainly apatite; for the dog the principal precipitated salt was calcium carbonate (calcite form).

A microbiological study of dental calculus. II. The in vitro calcification of microorganisms from dental calculus.

A simple in vitro system has been used to culture 34 species of microorganisms derived from human calculus. A confluent growth on the surface of an agar dise, was subjected to a daily 4 hr incubation in culture medium followed by 20 hr in a metastable solution of calcium phosphate, in a simplified organ culture vessel, for 7–17 days. Smears, taken daily, were stained by Von Kossa's method for the demonstration of calcification. 18 species showed evidence of calcification. In addition to the previously reported Bacterionema matruchotii, Streptococcus salivarius, Streptococcus sanguis (Sherman type 1), Veillonela alcalescens and a Neisseria species, calcification was also demonstrated in Actinomyces naeslundii, 1 strain of Actinomyces viscosus, an unidentified catalase positive facultative Gram‐positive rod, Staphylococcus epidermidis, Micrococcus varians, Eikenella corrodens, a Campylobacter sp., Eubacterium saburreum, an unidentified Gram‐negative rod, Haemophilus aphrophilus, Haemophilus segnis, Bacteroides melaninogenicus and Propionibacterium acnes.The Gram‐negative flore of calculus thus shares with the more frequently studied Gram‐positive species the property of in vitro calcification. Since the surface of calculus is covered with plaque containing a high proportion of Gram‐negative microorganisms, it is suggested that they may play a larger part in the production of calculus than had been indicated previously.

The Seeded Growth of Calcium Phosphates. The Kinetics of Growth of Dicalcium Phosphate Dihydrate on Enamel, Dentin, and Calculus

The kinetics of growth of calcium phosphates on synthetic hydroxyapatite (HAP), human enamel, whole dentin, and human calculus has been studied at 37 C at pH values from 4.97 to 5.10 held constant by the pH-stat addition of base. Following an initial induction period, dicalcium phosphate dihydrate (DCPD) crystallization takes place on the surface of these solids in all cases, even though the solutions are highly supersaturated with respect to HAP. The second order crystal growth kinetics are characteristic of the crystallization of DCPD on pure DCPD seed material. The ability of the substrate surfaces to nucleate DCPD falls in the order, synthetic HAP greater than enamel greater than calculus greater than dentin. Nucleation of DCPD, which is completed during the initial induction period, is very sensitive to small changes in pH, from 4.99 to 5.10.

Hyaluronic acid in supragingival dental calculus.

A method is described for the isolation of heteropolysaccharides from human supragingival calculus. One component was identified as hyaluronic acid, by electrophoretic mobility, testicular hyaluronidase digestion and cetylpyridinium chloride profiles. No sulphated glycosaminoglycans were detected.

A sulphated glycopeptide in human supragingival calculus extracts

A method is described for the isolation and purification of a sulphated glycopeptide from human supragingival calculus. The compound was isolated after using EDTA treatment, 2 M CaCl2 extraction, proteolytic digestion, ethanol precipitation, and finally purified by DEAE cellulose chromatography. It migrated as a single component of cellulose acetate electrophoresis, and chemical and infrared spectral analysis showed the presence of covalently attached sulphate groups. The sulphated glycopeptide was distinguished from being a sulphated glycosaminoglycan.