A hypothesis of calcium stone formation: an interpretation of stone research during the past decades

An interpretation of previous and recent observation on calcium salt crystallization and calcium stone formation provide the basis for formulation of a hypothetical series of events leading to calcium oxalate (CaOx) stone formation in the urinary tract. The various steps comprise a primary precipitation of calcium phosphate (CaP) at high nephron levels, establishment of large intratubular and/or interstitial (sub-epithelial) aggregates of CaP. These crystal masses subsequently might be dissolved during periods with low urine pH. On the denuded surface of subepithelial or intratubularly trapped CaP, release of calcium ions can result in very high ion-activity products of CaOx, particularly during simultaneous periods with peaks of CaOx supersaturation. Crystals of CaOx may result from nucleation in the macromolecular environment surrounding the apatite crystal phase. In the presence of low pH, low citrate and high ion-strength of urine, formation of large CaOx crystal masses can be accomplished by self-aggregation of Tamm–Horsfall mucoprotein. Following dislodgment of the initially fixed CaOx stone embryo, the further development into to clinically relevant stone is accomplished by CaOx crystal growth and CaOx crystal aggregation of the retained stone material. The latter process is modified by a number of inhibitors and promoters present in urine. The retention of the stone is a consequence of anatomical as well as hydrodynamic factors.     

Penile Gangrene and Urethrocutaneous Fistula Following Transurethral Resection of Prostatic Carcinoma. A Case Report

Channel transurethral resection of prostate (TURP) is an accepted treatment for advanced carcinoma of prostate (CaP) to improve quality of life. We are presenting a case of penile gangrene and urethrocutaneous fistula following TURP in a CaP. This is the first case in literature to our knowledge.     

Difference in urinary stone components between obese and non-obese patients

The prevalence and incidence of urinary stone disease have been reported to be associated with body weight and body mass index (BMI). The aim of the study was to determine the difference in stone components among different BMI groups in patients with urolithiasis. Between Dec 2005 and Jan 2008, 907 urinary calculi were collected and analyzed by infrared spectroscopy. Most of the stones had been passed spontaneously, and some were collected during surgical manipulations. The data on patients’ gender, age, BMI at diagnosis, and stone composition were collected. The patients were classified as normal weight (18.5≤ BMI <24), overweight (24≤ BMI <27), or obese (BMI ≥27). Of the 907 patients with urinary stone disease, 27.7% had normal weight, 33.5% were overweight, and 38.8% were obese. The prevalence of calcium oxalate stones in the normal weight, overweight, and obese groups were 23.1, 30.6, and 34.9%, respectively (P = 0.002), and the prevalence of uric acid stones in the different groups was 2.8, 7.2, and 7.7%, respectively (P = 0.002). The prevalence of calcium oxalate and uric acid stones, but not that of calcium phosphate stones, increased with body size. There was a significant correlation between BMI and uric acid stones in the overweight and obesity groups, with odds ratios of 3.28 and 4.35, respectively. The prevalence and incidence of urinary stone disease were found to be associated with BMI. The percentage of uric acid and calcium oxalate stones was higher in obese than in non-obese patients. There was no apparent difference in the prevalence of calcium phosphate stones between obese and non-obese patients.     

Perioperative cardiopulmonary complications after cervical spine surgery in the prone position: the relationship between age and preoperative testing

Background  

Cardiac arrest during spine surgery in the prone position is difficult to manage as poor access makes cardiopulmonary resuscitation and defibrillation difficult. Advanced age is the maximal risk factor for cardiac arrest. Therefore, we wanted to determine the relationship between age and cardiac risk factors/pre-operating tests for cervical spine surgery in the prone position.     

Study of short-pulse laser propagation in biological tissue by means of the boundary element method

Propagation of short pulses of light through biological tissues can be studied by numerically solving the diffusion equation. The boundary integral method was used to convert the differential equation to integral form and the result was solved using the boundary element method. The effects of different optical parameters of the tissue, i.e. scattering, absorption coefficients and anisotropic factor, on temporal evolution of the diffusely reflected pulse were studied. The results were compared with those obtained using the finite difference time domain method and the boundary integral method was found to be more precise and faster than the last method. The method can be used to investigate reflected pulses in the study of cell morphology and tumours in different types of tissue.     

Are Laparoscopic Gastric Bypass After Gastroplasty and Primary Laparoscopic Gastric Bypass Similar in Terms of Results?

Background  

This retrospective study compares the results of primary gastric bypass (PGB) versus secondary gastric bypass (SGB) performed after gastroplasty.     

The Combination of Structural Parameters and Areal Bone Mineral Density Improves Relation to Proximal Femur Strength: An In Vitro Study with High-Resolution Peripheral Quantitative Computed Tomography

The aim of this study was to assess structural indices from high-resolution peripheral quantitative computed tomography (HR-pQCT) images of the human proximal femur along with areal bone mineral density (aBMD) and compare the relationship of these parameters to bone strength in vitro. Thirty-one human proximal femur specimens (8 men and 23 women, median age 74 years, range 50–89) were examined with HR-pQCT at four regions of interest (femoral head, neck, major and minor trochanter) with 82 μm and in a subgroup (n = 17) with 41 μm resolution. Separate analyses of cortical and trabecular geometry, volumetric BMD (vBMD), and microarchitectural parameters were obtained. In addition, aBMD by dual-energy X-ray absorptiometry (DXA) was performed at conventional hip regions and maximal compressive strength (MCS) was determined in a side-impact biomechanical test. Twelve cervical and 19 trochanteric fractures were confirmed. Geometry, vBMD, microarchitecture, and aBMD correlated significantly with MCS, with Spearman’s correlation coefficients up to 0.77, 0.89, 0.90, and 0.85 (P < 0.001), respectively. No differences in these correlations were found using 41 μm compared to 82 μm resolution. In multiple regression analysis of MCS, a combined model (age- and sex-adjusted) with aBMD and structural parameters significantly increased R ² values (up to 0.90) compared to a model holding aBMD alone (R ² up to 0.78) (P < 0.05). Structural parameters and aBMD are equally related to MCS, and both cortical and trabecular structural parameters obtained from HR-pQCT images hold information on bone strength complementary to that of aBMD.     

Sclerotherapy for lymphatic malformations in children: a scoping review

Purpose

This scoping review assesses the literature and summarizes the current evidence on sclerotherapy for the treatment of lymphatic malformations in pediatric patients.

Methods

A comprehensive search of published and unpublished literature was conducted using multiple databases. Title, abstract, and full-text screening was conducted by 2 independent clinicians. All discrepancies were resolved during consensus meetings.

Results

A total of 182 articles were retrieved. Forty-four articles were removed as duplicates, and 11 articles were added after reviewing prominent studies. After full-text abstraction, 44 articles and 2 conference proceedings (N = 882 patients) were included in the final results. Twelve articles were classified as level II and 34 articles as level IV evidence. Picibanil (OK-432) was the primary agent used in most included studies. Postinjection symptoms with OK-432 were primarily fever, swelling, and erythema at the site. Life-threatening complications were uncommon and involved postinjection swelling of cervical lesions causing airway compromise.

Conclusions

The literature regarding sclerotherapy for lymphatic malformations is of a low level of evidence and suffers from a lack of standardization. Randomized clinical trials focused on OK-432, bleomycin, or alcoholic solution of zein; standardized dosing protocols; and consistent and reliable outcome reporting will be necessary for further development of treatment guidelines.     

Biographical Sketch: Thomas Callaway,FRCS (1822–1869)

This biographical sketch on Thomas Callaway corresponds to the historic text, The Classic: A Dissertation Upon Dislocations and Fractures of the Clavicle and Shoulder-Joint (1849) available at DOI .