Changes in stone composition over two decades: evaluation of over 10,000 stone analyses.

To examine the changes in stone composition from 1990 to 2010. A retrospective review was performed of all renal and ureteral stones submitted from the state of Massachusetts to a single laboratory (Laboratory for Stone Research, Newton, MA) for the years 1990 and 2010. Stone composition was determined by infrared spectroscopy and/or polarizing microscopy.

A study of the test of supervisory skills.

In supervisory selection and development it is important to assess individuals' supervisory competencies. In a field study, the Test of Supervisory Skills was validated against a surrogate criterion of supervisory performance, based upon position classification and supervisory experience. Subjects (N=2406), workers and applicants of both sexes, were recruited from multiple sources, tested, and the data analyzed to evaluate the usefulness of the test in human resource management applications.

Gallstone detection at CT in vitro: effect of peak voltage setting.

This study was a retrospective single-institutional study approved by the Committee on Human Research and was HIPAA compliant. A waiver for informed consent was granted. The purpose of the study was to evaluate the effect of four peak voltage settings on the in vitro conspicuity of gallstones in an anthropomorphic phantom at computed tomography (CT).

A prescribed employee fitness program and job-related attitudes.

A prescribed physical fitness exercise program was initiated in a small furniture manufacturing plant. The present purpose was to investigate the effect of an intervention to change employees' attitudes and sense of well-being. The objective was to evaluate the changes in employees' attitudes (well-being) attributable to the exercise program.

Drug-induced urolithiasis.

Diagnostic and therapeutic drugs may enhance urolithiasis in one or a combination of ways, including: (1) alteration of urine pH in such fashion as to create an environment that increases the solubility of some lithogenic substances, (2) alteration of glomerular filtration rate, tubular reabsorption, and tubular secretion of drugs of endogenous substances so as to enhance promoters or impair inhibitors of urolithiasis, and (3) precipitation (e.g., drugs or their metabolites) to form a portion or all of a urolith.

Urolithiasis as a hazard of sulfonamide therapy.

We identified 40 patients (25 men and 15 women) who developed calculi composed totally or partially of sulfonamides (acetylsulfamethoxazole, sulfadiazine, and acetylsulfisoxazole) between 1980 and 1987. The incidence of sulfonamide stones is less than 1% of stones. Patient characteristics were determined from questionnaires sent to the patients and attending physicians.

Dissolution of calcified gallstones. Part II. Evaluation of edetic acid preparations for dissolution of residue after in vitro methyl tert-butyl ether treatment.

Rationale And Objectives: The authors assessed the potential of edetic acid (EDTA) preparations to dissolve the residue of calcified gallstones partially treated with methyl tert-butyl ether (MTBE).

Methods: Nineteen triplets (57 gallstones) were submitted to dissolution in EDTA, urea-EDTA, and an MTBE control for 48 hours after initial partial dissolution in MTBE for 24 hours. Results were compared with findings at specimen computed tomography and crystallographic analysis.

Dissolution of calcified gallstones. Part I. Correlation of in vitro dissolution kinetics in methyl tert-butyl ether with patterns of calcification by computed tomography.

Rationale And Objectives: The authors evaluated the relationship between stone computed tomography (CT) attenuation patterns and the kinetics of dissolution with methyl tertbutyl ether (MTBE).

Methods: Single moderately and heavily calcified gallstones from 40 patients were selected from a gallstone library and classified for pattern of calcification by in vitro CT scan (dense, rim, core, and laminated). Each stone was placed in a 10-mL aliquot of MTBE for 24 hours.

Prediction of gallstone composition: synthesis of CT and radiographic features in vitro.

Purpose: To test a morphoradiographic algorithm designed to predict the composition of gallstones with use of computed tomography (CT) to define calcification patterns.

Materials And Methods: Two reviewers retrospectively evaluated the radiographic features of 120 separate in vitro specimens (59 radiopaque and 61 radiolucent), then classified the stones into several categories of composition with the algorithm.

Results: The most useful features for prediction of cholesterol composition were, in order of decreasing importance, stone shape, absence of dense calcification on plain radiographs, overall CT attenuation not higher than that of water, presence of a second generation of smaller stones, and a peripheral cover of calcification detected on CT scans of aging cholesterol stones.

Triamterene nephrolithiasis: renewed attention is warranted.

Although triamterene has been known to contribute to urinary calculus formation, it has been presumed to be a rare phenomenon. Our review of stone analyses performed during the last decade by a single laboratory reveals an increasing incidence of triamterene stones. Awareness of the calculogenic potential of triamterene-containing medications should be re-emphasized.

The roles of clinical psychologists: a comparison of faculty models and student practicuum roles.

This article focuses on the definition of faculty education and training models, as compared to student field placement job roles. Both faculty models and student roles are described in terms of tasks and job skills that were judged important. An inverse factor analysis was performed for the task importance judgements, separately for the faculty sample and the student sample.

Cystine calculi--rough and smooth: a new clinical distinction.

Four stones each from 2 populations of cystine calculi, 1 with a rough external surface (cystine-R) and the other smooth (cystine-S), were studied for their crystal structure with stereoscopic and scanning electron microscopy. Two stones each of cystine-R and cystine-S, calcium oxalate monohydrate, calcium oxalate dihydrate, struvite plus apatite and brushite were fragmented with extracorporeal shock wave lithotripsy and the fragmentability was compared. Fragments resulting from cystine-R and cystine-S extracorporeal shock wave lithotripsy were examined under the stereoscope to assess the plane of cleavage or fracture.

Physical characteristics of gallstones removed at cholecystectomy: implications for extracorporeal shock-wave lithotripsy.

The criteria by which patients are selected for new, nonsurgical forms of gallstone therapy will influence the use of these techniques. We estimated the number of patients with gallbladder stones who are potentially suitable for extracorporeal shock-wave lithotripsy according to the current Food and Drug Administration protocol for the United States trials of the Dornier gallbladder lithotriptor. Exclusion criteria include patients with (1) more than three stones, (2) stones less than 0.

Computed tomographic analysis of urinary calculi.

Excised urinary calculi were subjected to computed tomographic (CT) scanning in an attempt to determine whether CT attenuation values would allow accurate analysis of stone composition. The mean, maximum, and modal pixel densities of the calculi were recorded and compared; the resulting values reflected considerable heterogeneity in stone density. Although uric acid and cystine calculi could be identified by their discrete ranges on one or more of these criteria, calcium-containing stones of various compositions, including struvite, could not be distinguished reliably.

Percutaneous catheter dissolution of cystine calculi.

In 11 kidneys with presumed cystine stones that were symptomatic and obstructing, percutaneous nephrostomy and stone lavage with either acetylcysteine-bicarbonate solution or tromethamine-E were performed. There were 7 complete stone dissolutions: 2 of 6 attempts with acetylcysteine-bicarbonate alone, 3 of 5 with tromethamine-E, 1 partial with acetylcysteine-bicarbonate, which was completed with tromethamine-E, and 1 proved mixed stone (cystine and calcium phosphate) that required acetylcysteine-bicarbonate and hemiacidrin. In 1 case tromethamine-E irrigation was 97 per cent complete but a few tiny caliceal fragments remained.

Determination of the chemical composition of urinary calculi by computerized tomography.

The clinical management of renal calculi would be aided if a direct in vivo determination of stone chemical composition could be made. We investigated the possibility of obtaining this information by a quantitative analysis of the computerized tomography scan images of 80 urinary calculi. Our results show that by using an appropriately calibrated computerized tomography scanner the differentiation of stone chemical composition can be made on the basis of 3 parameters, namely, absolute computerized tomography value at a single x-ray energy, the difference between computerized tomography values measured at 2 different x-ray energies, and computerized tomography value-frequency histograms (pixel patterns) of the stones.

A repeated dose-response study of methazolamide in glaucoma.

Twenty-two patients with open-angle glaucoma were given weekly courses of methazolamide at different dosages. Mean intraocular pressure reductions of 3.3, 4.

Trace elements in kidney stones from three areas in the United States.

A large number of trace elements has been found in calcium stones (whewellite, weddellite, and apatite) and in struvite. Significantly fewer elements, with lower abundances, are found in uric acid and cystine. With the exception of four trace elements (lead, silicon, strontium, and zine), the trace element assemblages are identical in the oxalates (whewellite and weddellite); struvite is also similar but with notable exceptions.

The presence of protein-bound gamma-carboxyglutamic acid in calcium-containing renal calculi.

The amino acid gamma-carboxyglutamic acid (Gla) is found in four blood-clotting proteins, in a bone protein, in kidney protein, and in the protein present in various ectopic calcifications. This paper reports the presence of Gla in the EDTA-soluble, nondialyzable proteins of calcium-containing renal calculi including calcium oxalate, hydroxyapatite, and mixed stores of apatite and struvite (MgNH4PO4). Calculi composed of pure struvite and those composed of only uric acid or cystine do not contain Gla.

Degree of sulfation in mucopolysaccharide sulfates in normal and stone-forming urines.

Mucopolysaccharides were extracted from both normal and stone-forming urines, and those from the stone-forming samples showed a higher degree of sulfation than those from normal urines, as determined by sulfate analysis and electrophoretic measurement. The sulfated mucopolysaccharides from stone-forming urines formed insoluble calcium salts, whereas those from normal urines generally remained soluble in the presence of calcium ion. Rachitic rat cartilage was found to have more highly sulfated mucopolysaccharides than normal rat cartilage.

Kidney stone matrix. Differences in acidic protein composition.

Organic matrices from kidney stones of several mineral compositions (calcium oxalate, uric acid, and apatite-struvite) were isolated and found to contain an abundance of acidic amino acids. The calcium oxalate stones contained 50% aspartic and glutamic acid residues while the uric acid stones contained over 65%. The apatite-struvite stones had only 30% of these two amino acid residues and also contained 20% glycine residues.

The riddle of Randall's plaques.

Randall described a pre-calculus lesion of the renal papilla in the 1930s and this was substantiated by others during the next decade and then largely ignored. This insignificant subepithelial calcification of the renal papilla. Randall's plaque type I, becomes the nucleus of at least 15% of calcium oxalate calculi, as demonstrated by apatite nuclei existing in papillary depression on the external stone surface.