Hypercalcaemia caused by calcium sulfate beads

Hypercalcaemia is a relatively common metabolic disturbance seen in hospitalised patients; however, given the complicated systems of calcium regulation, it can take a significant amount of time and testing to pinpoint the aetiology. This case discusses a patient who developed acute hypercalcaemia from calcium sulfate-containing antibiotic beads placed during an orthopaedic procedure. These beads are used in surgical procedures to fill gaps/voids in bony structures and for local delivery of antibiotics. The case highlights the importance of careful review of a patient's hospital course, including the administration of medical products that may not be clearly documented on a patient's medicine administration record when working up an unexplained finding.

Symptomatic hypercalcaemia following the use of calcium sulfate beads in periprosthetic joint infections

Calcium sulfate beads (CSBs) are used as a method of delivery of antibiotics in periprosthetic joint infections, non-union and chronic osteomyelitis.[[1-3]] Symptomatic hypercalcaemia can occur as a complication following the insertion of CSBs however it is rare and few cases have been reported.[[4-7]] The cause of hypercalcaemia is poorly understood.

Hip osteonecroses treated with calcium sulfate-calcium phosphate bone graft substitute have different results according to the cause of osteonecrosis: alcohol abuse or corticosteroid-induced

INTRODUCTION

The aim of the study was to assess the factors influencing the final results of treatment of the femoral head osteonecrosis (ONFH) with core decompression and bone substitute grafting. The special interest was focused on comparison between alcohol- and steroid-induced ONFHs.

MATERIAL AND METHODS

In this prospective study, a total of 53 patients (58 hips) in the mean age of 35.5 years were included: 29 had a history of alcohol use (32 hips) and 24 of steroid use (26 hips). The mean follow-up was 4.2 years (minimum 3 years).

RESULTS

At last follow-up, significant improvements were noted in the Harris Hip Score (HHS) (mean 44.0 vs 55.9 points, p < 0.00002) and VAS scores (mean 7.0 vs 5.8 points, p < 0.0002) for the whole ONFH cohort, comparing to pre-operative status. The degree of improvement did not differ between Ficat and Arlet grade II and grade III (mean 14.9 vs 6.2 points, respectively, p = 0.1). No change was found between the final and initial results in this group in the steroid group (HHS mean 42.2 vs 45.5 points, p = 0.5 and VAS mean 6.8 vs 6.5 points, p = 0.5), but the improvement was noted in the alcohol group (HHS mean 45.5 vs 64.4 points, p < 0.0001; VAS mean 7.1 vs 5.2 points, p < 0.0001) comparing to pre-operative status.

CONCLUSIONS

Presented treatment of ONFH significantly improves hip function, offers pain reduction, and gives similar functional improvement for hips scoring grade II and III on the Ficat and Arlet scale. A good response to operative treatment is seen in patients with alcohol-induced ONFH, but not in those with steroid-induced ONFH.

Modifications to advanced Core decompression for treatment of Avascular necrosis of the femoral head

BACKGROUND

"Advanced Core Decompression" (ACD) is a new technique for treatment of osteonecrosis of the femoral head (ONFH) that includes removal of the necrotic tissue using a percutaneous expandable reamer followed by refilling of the drill hole and the defect with an injectable, hard-setting, composite calcium sulphate (CaSO4)-calcium phosphate (CaPO4) bone graft substitute. As autologous bone has been shown to be superior to all other types of bone grafts, the aim of the study is to present and evaluate a modified technique of ACD with impaction of autologous bone derived from the femoral neck into the necrotic defect.

METHODS

A cohort of patients with an average follow-up of 30.06 months (minimum 12 months) was evaluated for potential collapse of the femoral head and any reasons that led to replacement of the operated hip. Only patients in stages 2a to 2c according to the Steinberg classification were included in the study.

RESULTS

In 75.9% the treatment was successful with no collapse of the femoral head or conversion to a total hip replacement. Analysis of the results of the different subgroups showed that the success rate was 100% for stage 2a lesions and 84.6% respectively 61.5% for stages 2b and 2c lesions.

CONCLUSIONS

Previous studies with a comparable follow-up reported less favourable results for ACD without autologous bone. Especially in stages 2b and 2c the additional use of autologous bone has a positive effect. In comparison to other hip-preserving techniques, the modified ACD technique is a very promising and minimally invasive method for treatment of ONFH.

TRIAL REGISTRATION

German clinical trials register ( DRKS00011269 , retrospectively registered).

Biocompatibility of artificial bone based on vancomycin loaded mesoporous silica nanoparticles and calcium sulfate composites

The aim of this study was to evaluate the in vitro and in vivo biocompatibility of artificial bone based on vancomycin loaded mesoporous silica nanoparticles and calcium sulfate composites. In vitro cytotoxicity tests by cholecystokinin octapeptide (CCK-8) assay showed that the 5%Van-MSN-CaSO4 and Van-CaSO4 bone cements were cytocompatible for mouse osteoblastic cell line MC3T3-E1. The microscopic observation confirmed that MC3T3-E1cells incubated with Van-CaSO4 group and 5%Van-MSN-CaSO4 group exhibited clear spindle-shaped changes, volume increase and maturation, showing that these cements supported adhesion of osteoblastic cells on their surfaces. In addition, the measurement of alkaline phosphatase activity revealed the osteoconductive property of these biomaterials. In order to assess in vivo biocompatibility, synthesized cements were implanted into the distal femur of twelve adult male and female New Zealand rabbits. After implantation in artificial defects of the distal femur, 5%Van-MSN-CaSO4 and Van-CaSO4 bone cements did not damage the function of main organs of rabbits. In addition, the Van-MSN-CaSO4 composite allowed complete repair of bone defects with new bone formation 3 months after implantation. These results show potential application of Van-MSN-CaSO4 composites as bone graft materials for the treatment of open fracture in human due to its mechanical, osteoconductive and potential sustained drug release characteristics and the absence of adverse effects on the body.

CERAMENT treatment of fracture defects (CERTiFy): protocol for a prospective, multicenter, randomized study investigating the use of CERAMENT™ BONE VOID FILLER in tibial plateau fractures

BACKGROUND

Bone graft substitutes are widely used for reconstruction of posttraumatic bone defects. However, their clinical significance in comparison to autologous bone grafting, the gold-standard in reconstruction of larger bone defects, still remains under debate. This prospective, randomized, controlled clinical study investigates the differences in pain, quality of life, and cost of care in the treatment of tibia plateau fractures-associated bone defects using either autologous bone grafting or bioresorbable hydroxyapatite/calcium sulphate cement (CERAMENT™|BONE VOID FILLER (CBVF)).

METHODS/DESIGN

CERTiFy (CERament™ Treatment of Fracture defects) is a prospective, multicenter, controlled, randomized trial. We plan to enroll 136 patients with fresh traumatic depression fractures of the proximal tibia (types AO 41-B2 and AO 41-B3) in 13 participating centers in Germany. Patients will be randomized to receive either autologous iliac crest bone graft or CBVF after reduction and osteosynthesis of the fracture to reconstruct the subchondral bone defect and prevent the subsidence of the articular surface. The primary outcome is the SF-12 Physical Component Summary at week 26. The co-primary endpoint is the pain level 26 weeks after surgery measured by a visual analog scale. The SF-12 Mental Component Summary after 26 weeks and costs of care will serve as key secondary endpoints. The study is designed to show non-inferiority of the CBVF treatment to the autologous iliac crest bone graft with respect to the physical component of quality of life. The pain level at 26 weeks after surgery is expected to be lower in the CERAMENT bone void filler treatment group.

DISCUSSION

CERTiFy is the first randomized multicenter clinical trial designed to compare quality of life, pain, and cost of care in the use of the CBVF and the autologous iliac crest bone graft in the treatment of tibia plateau fractures. The results are expected to influence future treatment recommendations.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov: NCT01828905.

Differential growth and yield by canola (Brassica napus L.) and wheat (Triticum aestivum L.) arising from alterations in chemical properties of sandy soils due to additions of fly ash

BACKGROUND

There is a need for field trials on testing agronomic potential of coal fly ash to engender routine use of this technology. Two field trials were undertaken with alkaline and acidic fly ashes supplied at between 3 and 6 Mg ha⁻¹ to acidic soils and sown to wheat and canola at Richmond (Eastern Australia) and to wheat only at Merredin (Western Australia).

RESULTS

Ash addition marginally (P< 0.10) raised the pH in the top soil layers at both sites. The exceptionally dry season at both sites constrained yields and thwarted any likelihood of gaining yield benefits from ash-induced improvements in soil conditions. Yield improvements due to ash addition were absent at Merredin and only marginal at Richmond, where no elevated accumulation of B, Mo, Se, P or S in either the straw or seeds of wheat was observed; canola increased accumulation of Mo and Se in its shoot with acidic fly ash, but it was well below phyto toxic levels. Simulations of wheat using APSIM at Richmond over a 100-year period (1909-2008) predicted yield increases in 52% of years with addition of ash at 3.0 Mg ha⁻¹ compared with 24% of years with addition of ash at 6.0 Mg ha⁻¹. The simulated yield increases did not exceed 40% over the control with addition of 6 Mg ha⁻¹ ash, but was between 40% and 50% with an addition rate of 3 Mg ha⁻¹.

CONCLUSION

We found no evidence of phytotoxicity in either crop in this unusually dry year and there is still a need for further field assessment in years with favourable rainfall to enable development of clear recommendations on fly ash rates for optimum yield benefits.

Calcium sulfate cement in contained traumatic metaphyseal bone defects

The aim of this study was to evaluate prospective patients with periarticular fractures where a meta physeal bone defect was grafted with high compressive calcium sulfate cement. The calcium sulfate cement MIIG X3, (Wright Medical Technology, Inc, Arlington, TN) was used in 45 patients with periarticular fractures--distal radial, tibial plateau, humeral head, and calcaneal fractures--to fill the metaphyseal defect. All fractures were treated either with open or closed reduction, fracture fixation, and the cement was applied openly or closed. Radiographs were evaluated for fracture reduction, joint line gap, and step, as well as for rate of graft replacement by bone. All fractures united without an additional procedure. There were no wound infections or other complications attributed to the graft. At three-month follow-up, a complete graft replacement by bone was observed in all fractures. Joint line step was not developed in any patient, but a joint line gap of 3 mm was observed postoperatively in one patient with a tibial plateau fracture. Loss of reduction occurred in one patient with an extra-articular distal radial fracture treated with closed reduction and k-wire fixation. Cement that escaped into the joint or the surrounding soft tissues was not visible at the six-week follow-up. In conclusion, the results of this study confirm the safety and the efficacy of this cement when it is used as graft with the appropriate fixation method in traumatic metaphyseal bone defects.

Effect of phosphogypsum amendment on soil physico-chemical properties, microbial load and enzyme activities

Phosphogypsum (PG) is produced as a solid waste from phosphatic fertilizer plants. The waste slurry is disposed off in settling ponds or in heaps. This solid waste is now increasingly being used as a calcium supplement in agriculture. This study reports the effectof PG amendmenton soil physico chemical properties, bacterial and fungal count and activities of soil enzymes such as invertase, cellulase and amylase over an incubation period of 28 days. The highest mean percent carbon loss (55.98%) was recorded in 15% PG amended soil followed by (55.28%) in 10% PG amended soil and the minimum (1.68%) in control soil. The highest number of bacterial colonies (47.4 CFU g(-1) soil), fungal count (17.8 CFU g(-1) soil), highest amylase activity (38.4 microg g(-1) soil hr(-1)) and cellulase activity (38.37 microg g(-1) soil hr(-1)) were recorded in 10% amended soil. Statistically significant difference (p<0.05) has been recorded in the activities of amylase and cellulase over the period of incubation irrespective of amendments. Considering the bacterial and fungal growth and the activities of the three soil enzymes in the control and amended sets, it appears that 10% PG amendment is optimal for microbial growth and soil enzyme activities.

Acute intraoperative reactions during the injection of calcium sulfate bone cement for the treatment of unicameral bone cysts: a review of four cases

Unicameral bone cysts can predispose patients to pathologic fracture and deformities of growth. Treatment options vary from continuous decompression with transcortical placement of a cannulated screw to percutaneous aspiration and injection of medical-grade calcium sulfate. From 2005 to 2007, we treated 22 patients with unicameral bone cysts using aspiration and injection of calcium sulfate. Three patients experienced acute laryngospasm and one patient developed tachyarrhythmia, temporarily, associated with injection of calcium sulfate. All reactions occurred in patients under age 18 without predisposing risk factors and resolved spontaneously with supportive care. Although the mechanism is unclear, we hypothesize that these reactions are either due to the nociceptive stimulus of the calcium sulfate injection or a systemic calcium bolus. Clinicians using this product for this indication should be aware that such reactions may occur. We suggest endotracheal intubation and communication to the anesthesiologist about the time of the injection in preparation for these idiopathic responses. Further research is necessary to determine exactly how this reaction occurs and how it can be avoided.

Comparative performance of three ceramic bone graft substitutes

BACKGROUND CONTEXT

A number of different synthetic calcium-based bone graft substitutes (BGS) are currently available for clinical use. There is, however, a lack of comparative performance data regarding the relative efficacy of these materials when placed in an osseous defect site.

PURPOSE

To compare the rate, quality, and extent of osseous healing in a standard rabbit defect model for three commercially available BGS materials by measuring early bone formation and completion of defect healing and to identify whether rapid scaffold resorption stimulated or impaired bone healing.

STUDY DESIGN

Osteochondral defects, 4.8 mm in diameter and 6 to 7 mm deep, were made through the articular surface into the subchondral bone of the femoral condyle of New Zealand White rabbits and filled with cylindrical pellets of one of three commercially available BGS materials: dense calcium sulfate (DCaS), ultraporous tricalcium phosphate (beta-TCP), and porous silicated calcium phosphate (Si-CaP). The repair response was examined at 1, 3, 6, and 12 weeks after surgery (n=4 per BGS per time point).

METHOD

Qualitative histological and quantitative histomorphometric (% new bone, % bone graft substitute, capillary index, and mineral apposition rates) analysis.

RESULTS

Rapid resorption of D-CaS, primarily through dissolution, elicited a mild inflammatory response that left the defect site empty before significant quantities of new bone were formed. Both beta-TCP and Si-CaP scaffolds supported early bone apposition (<1 week). However, beta-TCP degradation products subsequently provoked an inflammatory response that impaired and reversed bone apposition within the defect site. The Si-CaP scaffolds appeared to be more stable and supported further bone apposition, with the development of an adaptive bone-scaffold composite; cell-mediated resorption of scaffold and new bone were observed in response to local load and contributed to the production of a functional repair within the defect site.

CONCLUSIONS

Rapid BGS resorption impaired the regenerative ability of local bone via three pathways: 1) insufficient persistence of an osteoconductive scaffold to encourage bone apposition, 2) destabilization of early bony apposition through scaffold disintegration, and 3) stimulation of an inflammatory response by elevated levels of particulate degradation products. This had a significant impact on the ultimate rate of healing. D-CaS did not stimulate early bone apposition, but bone repair was more advanced in D-CaS-treated defects at 12 weeks as compared with those treated with beta-TCP, despite the beta-TCP supporting direct bone apposition at 1 week. Si-CaP appeared to provide a more stable osteoconductive scaffold, which supported faster angiogenesis and bone apposition throughout the defect site, with the development of a functionally adaptive trabecular structure through resorption/remodelling of both scaffold and new bone. There was rapid formation of mineralized tissue at week 1 within the center of the defect and complete infiltration with dense, predominantly mature bone by weeks 3 to 6. The progressive remodeling of bone ingrowth and scaffold to reflect the distribution of local host tissue, combined with histological evidence of targeted osteoclastic resorption of both scaffold and bone, suggest that bone adaptation within the scaffold could be in response to Wolff's law. Although this model may not directly translate to a spinal fusion model and the products may vary according to the environment, these results suggest that, in patients in whom bone regeneration may be compromised, the degradation observed with some resorbable bone grafts may contribute to the decoupling of bone regeneration and resorbtion within the graft site, which may ultimately lead to incomplete bone repair.

Occupational exposure to carbon/coke fibers in plants that produce green or calcined petroleum coke and potential health effects: 1. Fiber characteristics

Carbon/coke fibers are found in bulk samples of calcined petroleum coke. Carbon/coke and other fibers, including calcium silicate, cellulose, gypsum, and iron silicate, have been found in exposure monitoring of workers who make or handle green or calcined petroleum coke. Carbon/coke fibers are not classified or regulated as carcinogens by any agency, and the available literature (summarized in this article) has not reported significant adverse health effects associated with exposure to these fibers or dusts containing these fibers. However, available epidemiological and toxicological studies have limitations that prevent a definitive assessment of carbon/coke fiber toxicity. Therefore, it is prudent to monitor and control workplace concentrations. Analyses by transmission electron microscopy (TEM) indicate that the carbon/coke fibers are amorphous, irregularly shaped, and generally rather short (94% less than 20 microm long). Nearly all carbon/ coke fibers satisfying NIOSH 7400 B counting criteria are detectable by phase-contrast optical microscopy (PCOM), which permits the use of a highly efficient sequential sampling strategy for analysis. Data are presented on the distribution of carbon/coke structure and fiber lengths and diameters. Bootstrap resampling results are presented to determine confidence intervals for structure/fiber length and diameter. Data on time-weighted average concentrations are given in a companion article, but nearly all time-weighted average carbon/coke fiber concentrations were beneath 0.1 fibers per milliliter.

A temporary filling material may cause cusp deflection, infractions and fractures in endodontically treated teeth

AIM

To test the hypothesis that Coltosol F might cause infractions and cusp fracture in root-filled teeth because of material expansion.

METHODOLOGY

Thirty-two extracted human molar teeth were root filled and prepared with mesial-occlusal-distal (MOD) cavities with or without undercuts. The specimens were filled proximally with glass-ionomer cement and then occlusally with either Coltosol F or zinc oxide eugenol (ZOE). The tooth specimens were kept in water at 37 degrees C for a period of 20 days, and every second day the intercusp distance (ICD) of each specimen was measured in a travelling microscope, and the number of infraction lines as well as fractures were noted.

RESULTS

The number of infraction lines increased in teeth filled with Coltosol F. Between day 8 and 16, seven of 16 teeth filled with Coltosol F showed fracture and exhibited a mean increase in ICD of 316 +/- 156 microm. Teeth filled with ZOE did not show an increase in number of infraction lines or in ICD, and none showed fracture.

CONCLUSIONS

The hygroscopic expansion of Coltosol F in a cavity may lead to cusp deflection, infraction development and fracture. Masticatory forces will in vivo aggravate this unfavourable condition. The material is not recommended for temporary filling in root-filled teeth except for a few days.

Nanocrystalline hydroxyapatite and calcium sulphate as biodegradable composite carrier material for local delivery of antibiotics in bone infections

The use of polymethylmetacrylate beads for local delivery of antibiotics requires a second surgical procedure for their removal and resorbable calcium sulphate exhibits cytotoxic effects. In this work, a bioresorbable composite of calcium sulphate and nanoparticulate hydroxyapatite (PerOssal was studied regarding its antibiotic release properties and biocompatibility. Material characteristics of plain PerOssal and pure calcium sulphate pellets were studied using scanning and electron microscopy and X-ray methods. Pellets were soaked with gentamicin and vancomycin, respectively. Release properties of both antibiotics from both materials were investigated over 10 days. Quantitative and qualitative cytotoxic assays were performed for biocompatibility testing. Specific surface was 106 m(2)/g for PerOssal and 2.2 m(2)/g for pure calcium sulphate. Almost complete elution of gentamicin was found for both carrier materials (94.7% for PerOssal vs. 95.8% for calcium sulphate) within 10 days, whereas vancomycin release was higher for PerOssal (96.3% vs. 74.8%). PerOssal showed higher initial and lower release after approximately 5 days compared to calcium sulphate. No significant in vitro cytotoxic differences were found between PerOssal and nontoxic cell culture medium. Calcium sulphate showed cytotoxic effects in two out of four tests. PerOssal exhibits excellent properties regarding resorption, biocompatibility, and antibiotic release.

Sensory and associated reactions to mineral dusts: sodium borate, calcium oxide, and calcium sulfate

Occupational exposure limits (OELs) for irritant dusts have had no quantifiable bases. This study (1) charted chemosensory feel, denoted chemesthesis here, to dusts of calcium oxide (1 to 5 mg/m(3)), sodium tetraborate pentahydrate [sodium borate] (5 to 40 mg/m(3)), and calcium sulfate (10 to 40 mg/m(3)); (2) examined correlates of the chemesthetic sensations; and (3) sought to illuminate the basis for potency. Twelve screened men exercised against a light load while they breathed air in a dome fed with controlled levels of dust for 20 min. Measured parameters included nasal resistance, nasal secretion, minute ventilation, heart rate, blood oxygenation, mucociliary transport time, and chemesthetic magnitude, calibrated to pungency of carbon dioxide. Subjects registered time-dependent feel from exposures principally in the nose, secondarily in the throat, and hardly in the eyes. Calcium oxide had the greatest potency, followed by sodium borate, with calcium sulfate a distant third. Of the physiological parameters, amount of secretion showed the best association with chemesthetic potency. That measure, as well as mucociliary transport time and minute ventilation, went into calculation of mass of dust dissolved into mucus. The calculations indicated that the two alkaline dusts increased in equal molar amounts with time. At equal molar concentrations, they had, to a first approximation, equal chemesthetic magnitude. On the basis of mass concentration in air or dissolved into mucus, calcium oxide and sodium borate differed in potency by a factor just above five, equal to the difference in their molecular weights. This relationship could inform the setting of OELs for a critical effect of irritation.

Effect of repeated vertical loads on microleakage of IRM and calcium sulfate-based temporary fillings

Temporary fillings are commonly used to seal endodontic access cavities between visits. IRM and Cavidentin were selected to represent two widely used groups of temporary filling materials. The first is a reinforced zinc oxide-eugenol preparation that is mixed at chairside, whereas the second is a ready-to-use calcium sulfate-based material that gained popularity due to its convenience of application. The seal provided by the aforementioned materials was studied using a radioactive tracer quantitative assay. When compared as passive temporary filling, the two provided a similar quality of seal. However, when subjected to repetitive "occlusal" cyclic loading of 4 kg, IRM was clearly superior to the calcium sulfate-based material. Whereas IRM maintained a reasonable seal, the calcium sulfate-based fillings deteriorated and lost the ability to seal. These results suggest that even though calcium sulfate-based materials may be useful when not subjected to any occlusal forces, IRM should be preferred whenever occlusal loads may be applied. Furthermore it is demonstrated that testing such materials for microleakage with no reference to mastication forces may be of limited value.

Environmental impacts of phosphogypsum vs. borrow pits in roadfill construction

A comparison was performed of the environmental impacts of using phosphogypsum versus conventional fill materials (e.g., from borrow pits) for road construction. The study compared a hypothetical roadway with an actual roadway in Florida; the two facilities differed only in that phosphogypsum was employed as fill material instead of conventional materials. The effect of the two construction approaches on the plant and animal communities was considered, as was the impact on the surface and ground water. A summary was made of the comparative impacts, and a comparison matrix was constructed using integral numbers to depict impacts ranging from -5 (most impact) to 0 (none) to + 5, showing most benefit of the part of the project on a given resource. Values were subjective, based upon investigators' experience. Four categories (plant and animal communities, water quality, water resources, and air quality) were considered. The cumulative total was +12 for phosphogypsum and -6 for conventional fill material.

Inflammatory reactions associated with a calcium sulfate bone substitute

OBJECTIVES

Loss of bone substance is a major source of disability that often requires grafting. Recently developed synthetic bone grafts have generated a lot of enthusiasm due to the lack of immunological reactions and infectious disease transmission risk. The current work describes some peculiar complications related to the use of calcium sulfate granules.

METHODS

15 implantations of calcium sulfate pellets Osteoset (Wright Medical Technology) were performed following resection of bone tumors at our service during 1999. Clinical or computerized tomography scans were available in all patients.

RESULTS

3 cases were encountered in which a severe inflammatory reaction developed. In one case serous drainage and an allergic reaction obligated graft removal. In another case, inflammation resolved two months following implantation. In the last case, wound breakdown occurred.

CONCLUSIONS

A sterile inflammatory response has previously hindered the use of absorbable poly-lactic and poly-glycolic acid rods. Apparently due to rapid graft resorption, the resulting calcium-rich fluid incites inflammation. The single case of an allergic reaction is interesting. An allergy to plaster of Paris is rare and related to minor additives. These were not present in the bone substitute used. Inflammatory complications should be considered when assessing the risk-benefit ratio of using different types of bone replacement materials, and comparing allogeneic grafts to synthetic ones.

Equipment malfunction in common hand surgical procedures. Complications associated with the pneumatic tourniquet and with the application of casts and splints

Pneumatic tourniquets and plaster of Paris splints and casts are the hallmarks of hand surgery, firmly entrenched as an adjunct in the routine treatment of upper extremity disorders. Because they are usually employed with a comparative degree of safety and because they are relatively simple devices from a technologic perspective. Little is written about them in the scientific literature. In this paper we extensively review their historical developments, physiologic effects, and common complications, and we attempt to provide a rationale for their safe and effective use.

Baking powder pica mimicking preeclampsia

We report a case of baking powder pica during pregnancy that was associated with maternal hypertension, hypokalemia, and elevated liver function tests. After discontinuation of baking powder ingestion and correction of electrolyte abnormalities, the blood pressure and the liver function tests normalized.

Pulmonary alveolar proteinosis and cement dust: a case report

Pulmonary alveolar proteinosis developed in a 29-year-old white man within 2 years of working as a cement truck driver. Pulmonary alveolar proteinosis (PAP), an uncommon respiratory disorder characterized by the accumulation of phospholipid material within the alveoli, has been described in association with exposure to silica, aluminum oxide, and a variety of dusts and fumes. Although a link between exposure to Portland cement and PAP has not been previously noted, this type of cement contains nearly 20% silica. Lung biopsy material, originally used to diagnose PAP, was reviewed under electron dispersive spectroscopy. Analysis indicated the presence of silica particles within the alveolar fluid and macrophages. A number of items support a causal relationship between exposure to cement dust and PAP: (1) the temporal sequence between assuming job duties and the development of the illness, (2) improvement following removal from further exposure, (3) dusty, unprotected working conditions, (4) the presence of silica within the cement, and (5) the alveolar fluid from periodic acid-Schiff-positive lung tissue.

Heat generation in plaster-of-Paris and resulting hand burns

Four female pupils at a technical school received hand burns while trying to make moulds of their hands using a dental plaster instead of ordinary plaster-of-Paris. In three cases the burns were so severe that several fingers had to be amputated due to irreversible tissue damage. The severity of the burns is explained on the basis of an experimental study where it was demonstrated that the temperature of hardening dental plaster rose to 70 degrees C and had a hardness that was 10-times greater than ordinary plaster-of-Paris. This should serve as a warning against the use of dental plaster in direct casting of living tissue. However, the technique used here is also considered dangerous, as ordinary plaster-of-Paris under certain circumstances could also cause severe burns.

Setting temperatures of plaster casts. The influence of technical variables

It is known that plaster-of-Paris casts can cause burns. Experiments were done to determine what factors are involved in causing an elevation of the temperature in a freshly applied cast. A glass tube filled with water between the temperatures of 36 and 39 degrees Celsius was used to simulate a leg for this study. Standard plaster casts were applied to the tube and the following variables were studied: different temperatures of the dip water; different thicknesses of the cast; the presence of plaster residue in the dip water; and the effect of the plaster of a pillow placed under the tube. It was found that if the temperature of the dip water was higher than 24 degrees Celsius or the thickness of the cast was greater than eight ply, or both, and if the pillow was used to limit the dissipation of heat from the cast, temperatures high enough to cause skin burns could occasionally be reached. Variable results indicated that these were the factors operating in practice and that a combination of them posed the greatest hazard.

Is polioencephalomalacia associated with high-sulfate diets?

During 1979 and 1980, rations containing high concentrations of gypsum or other sulfate salts were noticed to be a common feature of several episodes of polioencephalomalacia (PEM) diagnosed at the University of Missouri-Columbia Veterinary Medical Diagnostic Laboratory (VMDL). A retrospective study of 72 herds represented by all 6- to 18-month-old cattle necropsied at the VMDL between Sept 1 and Dec 31, 1980, was undertaken. Information about diet and husbandry was collected for each herd by interviews with the owner. Polioencephalomalacia occurred in 18 of 21 herds fed high-sulfate (greater than 2 % sulfate) rations, but in only 1 of 51 herds not fed such rations. The data demonstrated a statistically significant and possible causal relationship between PEM in cattle and high-sulfate rations.

Plaster of paris as an alloplastic implant in the frontal sinus

The use of calcium sulfate (plaster of Paris) has been advocated to repair bony defects because of its unique capability of stimulating osteoneogenesis. Plaster of Paris can be used as a bony alloplast, and it can be analyzed histologically. Sinus roentgenograms and technetium Tc 99m medronate bone scanning further support the use of plaster of Paris as an alloplast and assess its osteoneogenic capacity when implanted in the frontal sinus of dogs; complete bone regeneration was demonstrated in six dogs within four to six months. The use of plaster of Paris for bone reconstruction in the head and neck can be applied in surgery. The experience with plaster of Paris to date, although limited, shows it to be safe and highly encouraging as an effective bone allograft.

[Expediency of plastic surgery methods with osteomyelitic cavities]

The fitness of plaster filling, Schede's method, muscular pedicled autograft and of 3 biopolymeric compositions with the use of ultrasound for the grafting of bone cavities was tested in 206 experiments on dogs. The basic possibility of bone cavity filling with a biopolymeric composition was demonstrated.

Dental lead, blood lead, and pica in urban children

Lead storage in teeth was evaluated by examining the lead concentration in deciduous teeth of 32 children whose habits of pica and state of lead exposure had been studied when they were between 1 and 3 years of age. Concentratios of lead in their teeth depended on the reported amount of paint or plaster intake and the duration of exposure. The mean dental concentration of lead in exposed children was significantly higher than the mean value in 36 controls, who presumably did not have undue exposure to lead. A difference in dental lead concentration related to living area was noted. The significant difference in lead content of teeth between the two groups, even though the concentrations of lead in blood at 8 years of age were similar, emphasizes the importance of dental lead measurments for retrospective studies of lead exposure.