Closed Suction Drainage after Total Knee Arthroplasty with Concomitant Intravenous Tranexamic Acid Administration

Drain use in total knee arthroplasty (TKA) remains controversial. Use has been associated with increased complications, particularly postoperative transfusion, infection, increased cost, and longer hospital stays. However, studies examining drain use were performed before widespread adoption of tranexamic acid (TXA), which markedly reduces transfusion without increasing venous thromboembolism events. We aim to investigate incidence of postoperative transfusion and 90-day return to the operating room (ROR) for hemarthrosis in TKA with use of drains and concomitant intravenous (IV) TXA. Primary TKAs from a single institution were identified from August 2012 to December 2018. Inclusion criteria were primary TKA, age 18 years and over where use of TXA, drains, anticoagulant, and pre- and postsurgical hemoglobin (Hb) were documented during the patient's admission. Primary outcomes were 90-day ROR specifically for hemarthrosis and rate of postoperative transfusion. A total of 2,008 patients were included. Sixteen patients required ROR, three of which were due to hemarthrosis. Drain output was statistically higher in the ROR group (269.3 vs. 152.4 mL, p = 0.05). Five patients required transfusion within 14 days (0.25%). Patients requiring transfusion had significantly lower presurgical Hb (10.2 g/dL, p = 0.01) and 24-hour postoperative Hb (7.7 g/dL, p < 0.001). Drain output between the transfusion and no transfusion groups varied significantly (p = 0.03), with transfusion patients having higher postoperative day 1 drain output of 362.6 mL and total drain output of 376.6 mL. In this series, postoperative drain use with concomitant weight-based IV TXA is shown to be safe and efficacious. We observed exceedingly low risk of postoperative transfusion compared with prior reports of drain use alone as well as preserved low rate of hemarthrosis that has previously been positively linked to drain use.

Role of the Coiled-Coil Domain in Allosteric Activity Regulation in Soluble Guanylate Cyclase

Soluble guanylate cyclase (sGC) is the primary nitric oxide (NO) receptor in higher eukaryotes, including humans. NO-dependent signaling via sGC is associated with important physiological effects in the vascular, pulmonary, and neurological systems, and sGC itself is an established drug target for the treatment of pulmonary hypertension due to its central role in vasodilation. Despite isolation in the late 1970s, high-resolution structural information on full-length sGC remained elusive until recent cryo-electron microscopy structures were determined of the protein in both the basal unactivated state and the NO-activated state. These structures revealed large-scale conformational changes upon activation that appear to be centered on rearrangements within the coiled-coil (CC) domains in the enzyme. Here, a structure-guided approach was used to engineer constitutively unactivated and constitutively activated sGC variants through mutagenesis of the CC domains. These results demonstrate that the activation-induced conformational change in the CC domains is necessary and sufficient for determining the level of sGC activity.

Characterization of a unique polysaccharide monooxygenase from the plant pathogen Magnaporthe oryzae

Blast disease in cereal plants is caused by the fungus Magnaporthe oryzae and accounts for a significant loss in food crops. At the outset of infection, expression of a putative polysaccharide monooxygenase (MoPMO9A) is increased. MoPMO9A contains a catalytic domain predicted to act on cellulose and a carbohydrate-binding domain that binds chitin. A sequence similarity network of the MoPMO9A family AA9 showed that 220 of the 223 sequences in the MoPMO9A-containing cluster of sequences have a conserved unannotated region with no assigned function. Expression and purification of the full length and two MoPMO9A truncations, one containing the catalytic domain and the domain of unknown function (DUF) and one with only the catalytic domain, were carried out. In contrast to other AA9 polysaccharide monooxygenases (PMOs), MoPMO9A is not active on cellulose but showed activity on cereal-derived mixed (1→3, 1→4)-β-D-glucans (MBG). Moreover, the DUF is required for activity. MoPMO9A exhibits activity consistent with C4 oxidation of the polysaccharide and can utilize either oxygen or hydrogen peroxide as a cosubstrate. It contains a predicted 3-dimensional fold characteristic of other PMOs. The DUF is predicted to form a coiled-coil with six absolutely conserved cysteines acting as a zipper between the two α-helices. MoPMO9A substrate specificity and domain architecture are different from previously characterized AA9 PMOs. The results, including a gene ontology analysis, support a role for MoPMO9A in MBG degradation during plant infection. Consistent with this analysis, deletion of MoPMO9A results in reduced pathogenicity.

Batter's Shoulder: Clinical Outcomes and Return to Sport

Background

Batter’s shoulder has been defined as an acute posterior subluxation of the lead shoulder during a baseball swing causing a traumatic tear of the posterior labrum. There are limited data correlating repair techniques with return-to-play information but none utilizing standardized outcome measures. The purpose of this study is to examine a case series of patients for postoperative return-to-play and obtain follow-up using standardized outcome measures.

Methods

We retrospectively identified 10 patients with a batter’s shoulder injury. Patients were included if they met the criteria for batter’s shoulder injury. We attempted contact via telephone to complete Western Ontario Shoulder Instability (WOSI) and Disability of Arm Shoulder and Hand (QuickDASH) evaluations. We successfully reached five of the patients. The minimum follow-up was one year and the maximum was 11 years.

Results

All five patients in our cohort were able to return to play at the previous level without limitation. Patients reported a very low percentage limitation on the WOSI and QuickDASH questionnaires and results are detailed further on. Range of motion (ROM) and strength were not affected.

Conclusion

Batter’s shoulder is an infrequent cause of posterior labral tearing, leading to a painful swing that can limit sports activity. In our limited series, all patients treated with arthroscopic repair were able to return to play at the previous level, confirming a significantly improved prognosis for a batter’s shoulder injury in contrast to return to play after other causes of posterior labral tears.

Convergent allostery in ribonucleotide reductase

Ribonucleotide reductases (RNRs) use a conserved radical-based mechanism to catalyze the conversion of ribonucleotides to deoxyribonucleotides. Within the RNR family, class Ib RNRs are notable for being largely restricted to bacteria, including many pathogens, and for lacking an evolutionarily mobile ATP-cone domain that allosterically controls overall activity. In this study, we report the emergence of a distinct and unexpected mechanism of activity regulation in the sole RNR of the model organism Bacillus subtilis. Using a hypothesis-driven structural approach that combines the strengths of small-angle X-ray scattering (SAXS), crystallography, and cryo-electron microscopy (cryo-EM), we describe the reversible interconversion of six unique structures, including a flexible active tetramer and two inhibited helical filaments. These structures reveal the conformational gymnastics necessary for RNR activity and the molecular basis for its control via an evolutionarily convergent form of allostery.

Ribonucleotide reductase (RNR) catalyzes the conversion of ribonucleotides to deoxyribonucleotides, which is an essential step in DNA synthesis. Here the authors use small-angle X-ray scattering, X-ray crystallography, and cryo-electron microscopy to capture active and inactive forms of the Bacillus subtilis RNR and provide mechanistic insights into a convergent form of allosteric regulation.

An endogenous dAMP ligand in Bacillus subtilis class Ib RNR promotes assembly of a noncanonical dimer for regulation by dATP

The high fidelity of DNA replication and repair is attributable, in part, to the allosteric regulation of ribonucleotide reductases (RNRs) that maintains proper deoxynucleotide pool sizes and ratios in vivo. In class Ia RNRs, ATP (stimulatory) and dATP (inhibitory) regulate activity by binding to the ATP-cone domain at the N terminus of the large α subunit and altering the enzyme's quaternary structure. Class Ib RNRs, in contrast, have a partial cone domain and have generally been found to be insensitive to dATP inhibition. An exception is the Bacillus subtilis Ib RNR, which we recently reported to be inhibited by physiological concentrations of dATP. Here, we demonstrate that the α subunit of this RNR contains tightly bound deoxyadenosine 5'-monophosphate (dAMP) in its N-terminal domain and that dATP inhibition of CDP reduction is enhanced by its presence. X-ray crystallography reveals a previously unobserved (noncanonical) α2 dimer with its entire interface composed of the partial N-terminal cone domains, each binding a dAMP molecule. Using small-angle X-ray scattering (SAXS), we show that this noncanonical α2 dimer is the predominant form of the dAMP-bound α in solution and further show that addition of dATP leads to the formation of larger oligomers. Based on this information, we propose a model to describe the mechanism by which the noncanonical α2 inhibits the activity of the B. subtilis Ib RNR in a dATP- and dAMP-dependent manner.

Transient Thermal Response of a Guarded-Hot-Plate Apparatus for Operation Over an Extended Temperature Range

A mathematical model is presented for a new-generation guarded-hot-plate apparatus to measure the thermal conductivity of insulation materials. This apparatus will be used to provide standard reference materials for greater ranges of temperature and pressure than have been previously available. The apparatus requires precise control of 16 interacting heated components to achieve the steady temperature and one-dimensional heat-transfer conditions specified in standardized test methods. Achieving these criteria requires deriving gain settings for the 16 proportional-integral-derivative (PID) controllers, comprising potentially 48 parameters. Traditional tuning procedures based on trial-and-error operation of the actual apparatus impose unacceptably lengthy test times and expense. A primary objective of the present investigation is to describe and confirm the incremental control algorithm for this application and determine satisfactory gain settings using a mathematical model that simulates in seconds test runs that would require days to complete using the apparatus. The first of two steps to achieve precise temperature control is to create and validate a model that accounts for heating rates in the various components and interactions with their surroundings. The next step is to simulate dynamic performance and control with the model and determine settings for the PID controllers. A key criterion in deriving the model is to account for effects that significantly impact thermal conductivity measurements while maintaining a tractable model that meets the simulation time constraint. The mathematical model presented here demonstrates how an intricate apparatus can be represented by many interconnected aggregated-capacity masses to depict overall thermal response for control simulations. The major assemblies are the hot plate with four subcomponents, two cold plates with three subcomponents each, and two edge guards with three subcomponents each. Using symmetry about the hot plate, the number of components in the simulation model is reduced to 12 or 15, depending on the mode of operation for the apparatus. Configurations of the main components with embedded heating elements were carefully designed earlier using detailed finite-element analyses to give essentially isothermal surfaces and one-dimensional heat flow through test specimens. It is not tractable, or perhaps justified, to extend these prior analyses to simulate the controlled transient responses of the apparatus. The earlier design criterion does, however, support the aggregated-capacity simplification implemented in the present thermal model. The governing equations follow from dynamic energy balances on components with controlled heating elements and additional intermediate ("floating") components. Thermal bridges comprise conduction paths, with and without surface convection and radiation, between components and fixed-temperature "heat sinks." An implicit finite-difference numerical method was used to solve the resulting system of first-order differential equations. The mathematical model was initially validated using measurement data from test runs where a step change in heating rate was applied to single elements in turn, and component temperatures were recorded up to a nearly steady condition. Thermocouples and standard platinum resistance thermometers were used to measure temperatures, and thermopiles were used to measure temperature differences. Next, extensive simulations were conducted with the mathematical model to estimate suitable gain settings for the various controllers. The criteria were tight temperature control after reaching set points and acceptable times to achieve quasi-steady-state operation. Comparisons between measurements and predicted temperatures for heated components are presented. The results show that the model incorporating the above simplifying approximations is satisfactory for components comprising the hot-plate and cold-plate assemblies. For the edge guards, however, the conventional aggregated-capacity criteria are not as fully satisfied because of their configuration. Temperature variations in the edge guards, fortunately, have a lesser effect on the accuracy of the thermal conductivity measurements. Therefore, the thermal response model is deemed satisfactory for simulating PID feedback to investigate "closed-loop" control of the apparatus, thus meeting the primary objective.

X-ray Scattering Studies of Protein Structural Dynamics

X-ray scattering is uniquely suited to the study of disordered systems and thus has the potential to provide insight into dynamic processes where diffraction methods fail. In particular, while X-ray crystallography has been a staple of structural biology for more than half a century and will continue to remain so, a major limitation of this technique has been the lack of dynamic information. Solution X-ray scattering has become an invaluable tool in structural and mechanistic studies of biological macromolecules where large conformational changes are involved. Such systems include allosteric enzymes that play key roles in directing metabolic fluxes of biochemical pathways, as well as large, assembly-line type enzymes that synthesize secondary metabolites with pharmaceutical applications. Furthermore, crystallography has the potential to provide information on protein dynamics via the diffuse scattering patterns that are overlaid with Bragg diffraction. Historically, these patterns have been very difficult to interpret, but recent advances in X-ray detection have led to a renewed interest in diffuse scattering analysis as a way to probe correlated motions. Here, we will review X-ray scattering theory and highlight recent advances in scattering-based investigations of protein solutions and crystals, with a particular focus on complex enzymes.

Gas Phase Oxidation of Campholenic Aldehyde and Solution Phase Reactivity of its Epoxide Derivative

The rate constant for the OH reaction with campholenic aldehyde (CA) was measured using the flow tube-chemical ionization mass spectrometry method with a relative rate kinetics technique and was found to be (6.54 ± 0.52) × 10^-11 cm³ molecule^-1 s^-1 at 100 Torr pressure and 298 K. A mechanism for the formation of the observed products was developed for both NO-free and NO-present conditions. On the basis of measurements of the pressure dependent yields of the products, between 5 and 20% of the CA oxidation at atmospheric pressure is predicted to lead to campholenic aldehyde epoxide (CAE). The aqueous solution reaction rate constants for CAE were determined via NMR spectroscopy and were found to be (2.241 ± 0.036) × 10^-5 s^-1 for neutral conditions and 0.0989 ± 0.0053 M^-1 s^-1 for acid-catalyzed conditions at 298 K. The products of the CAE aqueous solution reaction were identified as an isomer of CAE and the aldehyde group hydrated form of this isomer. Unlike the isoprene-derived epoxide, IEPOX, a nucleophilic addition mechanism was not observed. On the basis of the rate constants determined for CA and CAE, it is likely that these species are reactive on atmospherically relevant time scales in the gas and aerosol phases, respectively. The results of the present study largely support a previous supposition that α-pinene-derived secondary organic aerosol may be influenced by the multiphase processing of various intermediate species, including those with epoxide functionality.

Thermal response simulation for tuning PID controllers in a 1016 mm guarded hot plate apparatus

A mathematical model has been developed and used to simulate the controlled thermal performance of a large guarded hot-plate apparatus. This highly specialized apparatus comprises three interdependent components whose temperatures are closely controlled in order to measure the thermal conductivity of insulation materials. The simulation model was used to investigate control strategies and derive controller gain parameters that are directly transferable to the actual instrument. The simulations take orders-of-magnitude less time to carry out when compared to traditional tuning methods based on operating the actual apparatus. The control system consists primarily of a PC-based PID control algorithm that regulates the output voltage of programmable power amplifiers. Feedback parameters in the form of controller gains are required for the three heating circuits. An objective is to determine an improved set of gains that meet temperature control criteria for testing insulation materials of interest. The analytical model is based on aggregated thermal capacity representations of the primary components and includes the same control algorithm as used in the actual hot-plate apparatus. The model, accounting for both thermal characteristics and temperature control, was validated by comparisons with test data. The tuning methodology used with the simulation model is described and results are presented. The resulting control algorithm and gain parameters have been used in the actual apparatus without modification during several years of testing materials over wide ranges of thermal conductivity, thickness, and insulation resistance values.

Effect of vitamin D in fluoride-treated rats

Fluoridated drinking water (30 mg and 100 mg F per liter) was used to induce rachitic changes in rats fed a vitamin D free diet containing calcium and phosphorus in a ratio of 1 : 1. Supplements of vitamin D3 (70 IU of cholecalciferol per week) completely prevented the rachitogenic effects of fluoride. This protective effect occurred despite evidence that vitamin D enhanced the intestinal absorption of fluoride.

Comparison of the maximum tolerated dose (MTD) dermal response in three strains of mice following repeated exposure to acrylic acid

The dermal response of three strains of mice (ICR, C3H and B6C3F1) exposed to repeated doses of 0, 1 or 4% acrylic acid was examined over 13 wk. Microscopic and gross changes to the skin were classified as being indicative of exceeding the maximum tolerated dose (MTD), reaching the MTD, or tolerating the dose based on proposed MTD guidelines established in US Environmental Protection Agency (EPA) Workshops on dermal carcinogenesis bioassays. A significant number of animals in all three strains with repeated exposure to 4% acrylic acid experienced skin irritation that was classified as having reached or exceeded the MTD compared with animals exposed to either 1% acrylic acid or the 0% acrylic acid acetone control. These results were observed within the first 3 wk of exposure, but there was some accommodation to irritation by 8 wk of exposure. Microscopic findings provided a more sensitive index for exceeding MTD than gross observations taken only at autopsy, but generally correlated well for MTD if gross observations were taken at regular intervals during treatment. That is, to set MTD, gross observations could be used if taken over the entire course of the exposure, but using microscopic findings was generally a more reliable or sensitive measure. EPA guidelines suggest that it is inappropriate to conduct a dermal bioassay at concentrations that exceed the MTD. Acrylic acid at 4% in acetone clearly exceeded the MTD based on microscopic or gross observation criteria. At 4%, strain differences were evident by gross observation only, with the ICR strain being less susceptible to irritation than C3H or B6C3F1 strains. These strain differences were not apparent with microscopic examination. Acrylic acid at 1% in acetone, although demonstrating signs of minimal irritation, was fairly well tolerated by all mice in all strains. Thus, acrylic acid at 1% in acetone, one-quarter of the concentration that was in clear excess of the MTD, would be the appropriate dose concentration for lifetime skin studies based on MTD criteria.

Exercise, age, and bones

Skeletal development in average healthy individuals is maximal at age 25 in women and at age 30 to 35 in men. However, there are significant racial differences, skeletal mass being greater in black than in white individuals. This difference appears best accounted for by increased muscle mass in blacks. Bed rest, immobilization, weightlessness (as in space flights), and aging induce a decrease in skeletal mass. The degree of osteopenia in the elderly depends partly on skeletal development during formative years and can be prevented from becoming severe by maintaining good nutritional status (calcium, vitamin D, protein) and physical activity. Maintenance or actual increase in muscle mass is a desired effect of appropriate physical activity, but excessive physical exercise may induce estrogen deficiency and menstrual irregularities in premenopausal women. In addition to diet and exercise, pharmacologic therapy (estrogens, androgens, diphosphonates, or calcitonin) is indicated in patients with significant osteoporosis.

Genetic toxicology of acrylic acid

Acrylic acid was tested for gene mutations in the in vitro CHO/HGPRT assay, for chromosome aberrations in CHO cells in culture, and for potential to induce unscheduled DNA synthesis in rat hepatocytes in culture. In vivo assays performed included the Drosophila sex-linked recessive lethal assay by both the feeding and injection routes, the in vivo cytogenetic assay in rat bone marrow cells after both a 1-day and 5-day oral dosing regimen, and a dominant lethal assay in mice by both an acute and 5-day dosing regimen. All results were negative (non-mutagenic) except for the in vitro chromosome aberration assay. This latter result is consistent with the previously reported possible clastogenic activity suggested by the results of the mouse lymphoma L5178Y TK locus assay in which a predominance of small-colony mutants was observed (Moore et al., Environmental and Molecular Mutagenesis 1988, 11, 49-63). The rapid clearance of acrylic acid in animals and the weight of evidence of genetic toxicity testing, including negative in vivo data in both somatic and germ cells, indicate a lack of genetic toxicity of acrylic acid in vivo.

Subchronic oral toxicity of cellulose acetate in rats

Cellulose acetate was administered by way of a dietary admixture to Sprague-Dawley rats (20/sex/group) at dose levels of 0, 500, 2500 and 5000 mg/kg body weight/day for 94-96 days. Physical observations, body weight and food consumption measurements were made before testing and throughout the study. Ophthalmoscopic examinations were conducted on all animals before testing and just prior to study termination. Haematology, clinical chemistry and urinalysis were performed at 1.5 and 3 months on 10 animals/sex/group. After 3 months of treatment the animals were killed, terminal body weights and organ weights were measured and ratios calculated. Histopathological examination of tissues from the control and high-dose groups was conducted. The evaluation of physical observations, ophthalmology, body weight, food consumption, haematology, clinical chemistry, organ-to-body-weight ratios, gross pathology and histopathology revealed no evidence of an adverse effect related to treatment with cellulose acetate.

Acute inhalation toxicity studies in several animal species of an ethylene oxide/propylene oxide copolymer (UCON 50-HB-5100)

An acute inhalation toxicity study in several species of animals with an ethylene oxide/propylene oxide copolymer (EO/PO) having a molecular weight of 4000 [UCON-50-HB-5100, CAS #9038-95-3] was designed to determine if any species variation could be shown. Species tested included: rats, mice, hamsters, guinea pigs, and dogs. The test material was administered as a respirable liquid aerosol for 4 hours at target concentrations of 50, 100, 200, and 500 mg/m3. A vehicle control group was exposed to a distilled water aerosol. The 4 hours LC50's were calculated to be 147 mg/m3 [rats], 174 mg/m3 [mice], 293 mg/m3 [guinea pigs] and 511 mg/m [hamsters]. The dog LC50 was determined to be greater than 500 mg/m3 since all the test animals survived exposure to this concentration. These values show that rats and mice were the most sensitive species with a declining response in guinea pigs, hamsters and dogs. Lung weights were increased at all exposure concentrations in rats, mice and hamsters. Lung weights were increased in guinea pigs at exposure concentrations of 100 mg/m3 and above. Lung weights in dogs were increased only at the 500 mg/m3 exposure concentration. Significant pathological changes were limited to the lungs and were more common in animals which died prior to scheduled sacrifice. Grossly, these lung changes consisted of red discoloration, edema, emphysema, and surface irregularities. Microscopic findings in the lungs included acute congestion and hemorrhage and, less commonly, acute interstitial inflammation.

Urinary calculi in hypercalcemic states

In this brief review of various hypercalcemic disorders and the likelihood of renal calculus formation, it is clearly evident that renal calculi occur much more often in hyperparathyroidism than in the other hypercalcemic states. Dystrophic calcification and nephrocalcinosis are common to all of the hypercalcemic disorders, including hyperparathyroidism, when the hypercalcemia is marked and the limit of solubility of calcium and phosphate in serum is approached. Interestingly, in sarcoidosis there are calcium oxalate crystals in variously distributed sarcoid granuloma, and the renal calculi are composed of calcium oxalate. By contrast, in hyperparathyroidism, the calculi composed of calcium phosphate predominate. This indicates a subtle and as yet undefined alteration in oxalate metabolism in sarcoidosis. An increase in urine pH occurs in hyperparathyroidism, and this enhances formation of crystalline calcium phosphate. However, the striking disparity between the frequency of calculus formation in hyperparathyroidism and that in other hypercalcemic disorders, several of which may be of relatively long duration, suggests that there indeed may be increased promoters of crystal formation in the urine of hyperparathyroid patients.

The effect of hypoparathyroidism on the aging skeleton

Serum concentrations of parathyroid hormone are frequently increased in elderly subjects. How much this increase may contribute to the development of osteoporosis in such subjects is unknown. Long-standing hypoparathyroidism has been reported to be accompanied by an increase in skeletal density. In seven consecutive women, aged 40 to 83 years, with hypoparathyroidism of at least 18 years duration, the mineral density in the lumbar vertebrae was measured by quantitative computed tomography (QCT) and dual photon absorptiometry (DPA). In these subjects, the bone mineral density by dual photon absorptiometry was 1.4 to 6.2 standard deviations above mean values for age-matched normal women. However, the mineral density of vertebral trabecular bone as determined by quantitative computed tomography was only slightly increased above values reported for normal women. The differences between the values determined by dual photon absorptiometry and quantitative computed tomography indicate that most of the increase in mineral density was a reflection of increased cortical bone. Roentgenograms of the metacarpals did not reveal consistent differences between normals and the hypoparathyroid subjects. These findings suggest the possibility that control of parathyroid function might be of value in treating osteoporotic patients.

Vitamin D deficiency in Florida, the Sunshine State

Several years may be required for development of clinically evident osteomalacia in previously healthy subjects deprived of exposure to sunlight or enriched dietary sources of vitamin D. In a survey of residents of a 120 bed VA nursing home who had been patients there for two to six years, 17 were found to have x-ray or laboratory findings suggestive of the presence of vitamin D deficiency. Bone biopsy in eight of these 17 patients revealed definite osteomalacia in three patients. Thus, vitamin D deficiency may develop in confined, nonvitamin D fortified patients in Florida just as in more northern climes. Daily exposure for 30 minutes to sunshine or oral administration of 2.5 mg of vitamin D2 or D3 twice yearly has been recommended to prevent deficiency of this vitamin.

Extracorporeal shock-wave lithotripsy: prevalence of renal stones 3-21 months after treatment

One hundred and four (70%) of the first 148 patients who underwent extracorporeal shock-wave lithotripsy (ESWL) at the University of Florida were evaluated for persistent or recurrent renal stone disease. Radiographs obtained 3-21 months after treatment showed that 53 (50%) of 106 treated kidneys were free of stones. In 48 of the 53 kidneys that contained stones, the stones were residual fragments dating from the period immediately after ESWL. New stones had developed in only five kidneys. The 50% incidence of stone-free kidneys 3-21 months after ESWL is less than the 65-90% rate reported by other institutions in the United States and Europe. After stone removal by ESWL, new stone formation occurs at a rate of 5%, which is much lower than the expected recurrence rate of 37-50%.

Extracorporeal shock-wave lithotripsy: long-term complications

Of 148 patients who had extracorporeal shock-wave lithotripsy (ESWL) for renal lithiasis in 1984, 21 (14%) returned after 17-21 months for renal function tests (21 patients) and blood pressure determination (20 patients). Quantitative radionuclide renography showed a statistically significant (p = .048) decrease in the percentage of effective renal plasma flow (ERPF) to the treated kidney. Two of these patients had developed hypertension requiring treatment but became normotensive when given medication. In the other patients there was a statistically significant increase in both systolic (p = .0002) and diastolic (p = .015) blood pressures. Information about blood pressure was also obtained from an additional 71 (48%) of the 148 patients; of the total 91 patients (61%) in whom blood pressures were obtained, seven (8%) had developed sufficiently severe hypertension to require treatment beginning within 21 months after ESWL. Side effects of ESWL for renal lithiasis include hemorrhage, edema, and acute tubular necrosis of the kidney. This form of renal trauma is associated with an immediate decrease in renal function of the treated kidney, and this decrease may be permanent. ESWL is also associated with the onset of hypertension, which may occur immediately or be delayed by several weeks or months. Although the pathogenesis remains unknown, hypertension is an important complication of ESWL in about 8% of patients.

Inhalation teratology studies of n-butyl mercaptan in rats and mice

n-Butyl mercaptan (n-BM) is used as a solvent and a chemical intermediate. Pregnant Charles River CD-1 mice and COBS CD rats were randomly assigned to a control group and to three n-BM-exposed groups of 25 rats and 25 mice each. The animals were exposed by whole-body inhalation to mean n-BM concentrations of 10, 68, or 152 ppm on a 6-hr daily exposure schedule. Rats were exposed on Gestation Days 6-19 and mice on Gestation Days 6-16. The control group was exposed to filtered air only on a comparable regimen. Cesarean sections were performed on all surviving mice on Gestation Day 17 and on all rats on Gestation Day 20. Seventeen of the n-BM-treated mice died: 8 at the 68-ppm level and 9 at the 152-ppm level; none of the n-BM-treated rats died. An increased postimplantation loss and increased early resorption occurred in mice exposed at 68 and 152 ppm, indicating embryotoxicity. An increased incidence of cleft palate was observed in mice exposed to 10 or 68 ppm which was not statistically significant. Total fetal abnormalities were statistically significantly different from controls at 68 ppm where maternal lethality was observed when based on the fetal unit although not when based on the litter unit. Rats exposed to 152 ppm or less demonstrated no terata.

Influence of aluminum on mineralization during matrix-induced bone development

A model of de novo mineralization employing matrix-induced endochondral bone formation in rats was used to study the short-term effects of aluminum on the deposition of calcium and phosphate in vivo. In experiments where systemic aluminum concentrations were elevated, the cellular processes associated with bone development appeared to be normal, if somewhat delayed, however precipitation of the mineral phase was prevented. This suggests a primary direct physical chemical effect of aluminum in vivo on calcification, as suggested by in vitro studies which demonstrate that aluminum is a potent inhibitor of calcium phosphate precipitation. Aluminum salts implanted locally with the matrix appeared to be toxic to the cellular processes leading to chondrogenesis and osteogenesis.

Relationship between experimentally induced crystalluria and relative supersaturation of various stone salts in rats

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.

The subchronic oral toxicity of polyphenylene sulfide

Polyphenylene sulfide was offered to Charles River CD rats for 6 months in the diet at concentrations of 0.00, 0.50, 2.75 and 5.00% (w/w). In this study, animals of both sexes consumed polyphenylene sulfide for 6 months without exhibiting compound-related effects. Parameters studied were: body weight, hematology, clinical chemistry, urinalysis, organ weights, gross pathology and histopathology.

Trace metal-citric acid complexes as inhibitors of calcification and crystal growth. II. Effects of Fe(III), Cr(III) and Al(III) complexes on calcium oxalate crystal growth

The high molecular weight Fe(III)-citric acid complex, formed at low ratios of citrate:iron in solution, has been shown to be an effective inhibitor of calcium oxalate crystal growth. This appears to be a specific reaction, since 2 other similar metal ions. Al(III) and Cr(III), exhibit no synergism with citric acid in this system. Because the low molecular weight Fe(III)-citric acid complex, formed at high ratios of citrate:iron, inhibits calcium phosphate precipitation but has no effect on calcium oxalate, the Fe(III)-citric acid system might have a selective biologic role in regulating the growth of calcium-containing urinary calculi in vivo.

Trace metal-citric acid complexes as inhibitors of calcification and crystal growth. I. Effects of Fe(III), Cr(III) and Al(III) complexes on calcium phosphate crystal growth

The crystal growth of calcium phosphate has been shown to be inhibited by a low molecular weight Fe(III)-citric acid complex formed when there are high ratios of citrate:iron at neutral pH in aqueous solution. Synergism with citric acid was also observed in systems containing Al(III) or Cr(III) ion, but different unknown complexes seemed to be involved. These results are in qualitative agreement with a preceding study involving calcification of an organic matrix. Since chelating agents like citric acid can compete with the storage proteins for iron, we suggest that the Fe(III)-citrate complexes studied here may be formed in vivo and participate in regulating biologic calcification.