A review of the mesotheliogenic potency of cleavage fragments found in talc

It has long been recognized that amphibole minerals, such as cleavage fragments of tremolite and anthophyllite, may exist in some talc deposits. We reviewed the current state of the science regarding the factors influencing mesotheliogenic potency of cleavage fragments, with emphasis on those that may co-occur in talc deposits, including dimensional and structural characteristics, animal toxicology, and the most well-studied cohort exposed to talc-associated cleavage fragments. Based on our review, multiple lines of scientific evidence demonstrate that inhaled cleavage fragments associated with talc do not pose a mesothelioma hazard.

Ethylene oxide review: characterization of total exposure via endogenous and exogenous pathways and their implications to risk assessment and risk management

This review is intended to provide risk assessors and risk managers with a better understanding of issues associated with total exposures of human populations to ethylene oxide from endogenous and exogenous pathways. Biomonitoring of human populations and lab animals exposed to ethylene oxide has relied upon the detection of hemoglobin adducts such as 2-hydroxyethylvaline (HEV), which provides a useful measure of total exposure to ethylene oxide from all pathways. Recent biomonitoring data from CDC provide an excellent characterization of total exposure to ethylene oxide to the general U.S. population by demographic factors such as age, gender, and race as well as smoking habit, which might be comparable to previous measurements reported for humans and lab animals. The biochemical pathways including gastrointestinal (production by bacteria) and systemic (enzymatic production) pathways by which endogenous ethylene is generated and converted to ethylene oxide are described. The relative importance of endogenous pathways and exogenous pathways via ambient air or tobacco smoke was quantified based upon available data to characterize their relative importance to total exposure. Considerable variation was noted for HEV measurements in human populations, and important sources of variation for all pathways are discussed. Issues related to risk assessment and risk management of human populations exposed to ethylene oxide are provided within the context of characterizing total exposure, and data needs for supporting future risk assessment identified.

Polymorphisms in the prostate-specific antigen gene promoter do not predict serum prostate-specific antigen levels in African-American men

A major problem with the use of serum prostate-specific antigen (PSA) in predicting prostate cancer risk is the considerable variability of such measurements. Cramer et al. identified a set of single-nucleotide polymorphisms (SNPs) in the upstream regulatory region of the PSA gene that were each associated with increased promoter activity and serum PSA, further suggesting that genotyping these SNPs could be useful in improving the predictive value of PSA screening. In order to replicate this finding, DNA samples from 475 African-American men were genotyped for the same SNPs and no association was observed with either serum PSA level or prostate cancer diagnosis.

Late proliferation of retinal Müller cell progenitors facilitates preferential targeting with retroviral vectors in vitro

During vertebrate neural retina development, the relationship between mitotic activity in progenitor cells and the acquisition of a mature cell phenotype remains an area of controversy. The Müller glial cell has long been recognized as one of the last cell types of the retina to mature, which occurs under the influence of cell-cell interactions. In this report we examine the acquisition of the Müller cell phenotype in relation to mitotic activity. Using immunohistochemical markers, we demonstrate that a gene product characteristic of mature Müller cells, the 2M6 antigen, is expressed in mitotically active cells, even after all the major retina architectural features have been laid down. Furthermore, we show that retroviral infection, a process that requires mitotically active cells, preferentially targets Müller cell progenitors when late embryonic retina is infected in vitro. The two lines of evidence are consistent with a model for Müller cell differentiation that includes a mitotically active progenitor that has already begun to express specific differentiation gene products.

Dose-independent pharmacokinetics of the cardioprotective agent dexrazoxane in dogs

A randomized, four-way cross-over design was used to assess the disposition of the cardioprotective agent, dexrazoxane, in four male beagle dogs following single I.V. administration of 10, 25, 50, and 100 mg kg-1 doses. Parent drug was quantified in plasma and urine with a validated high-pressure liquid chromatographic-electrochemical assay. A two-compartment open model adequately described the dexrazoxane plasma concentration versus time data. The terminal half-life ranged between 1.1 and 1.3 h and the apparent steady-state distribution volume was 0.67 L kg-1. The systemic clearance (CL) ranged from 10.3 to 11.5 mL min-1 kg-1, while estimates of renal clearance approximated the glomerular filtration rate (GFR approximately 3.2-4.9 mL min-1 kg-1). Over the dose range evaluated, CL was dose independent (ANOVA, p = 0.33), while concentration at the end of infusion (Cend) and the area under the concentration versus time curve (AUC) were directly proportional to the dose (r > 0.999). The blood cell to plasma partitioning ratio was approximately 0.517 and drug was essentially unbound to plasma proteins (fu approximately 0.95). Dexrazoxane appeared to be subject to low organ extraction, since the hepatic and renal drug extraction ratios were on the order of 0.228 +/- 0.054 and 0.184 +/- 0.024, respectively. These results suggest a relatively small drug distribution space (approximately equal to total-body water) and low tissue and plasma protein binding. In light of the low plasma protein binding and extraction ratio exhibited by dexrazoxane, metabolic capacity and renal function would appear to be the predominant variables affecting the CL of this drug. The constancy of the half-life, CL, and VSS with increasing dose indicates dose-independent disposition for dexrazoxane. Thus a linear increase in the systemic exposure can be predicted over this dose range.

Lack of effect of concomitant zidovudine on rifabutin kinetics in patients with AIDS-related complex

The effect of concomitant dosing with the antiretroviral agent zidovudine (ZDV) on the pharmacokinetics of rifabutin (RBT) was investigated under steady-state conditions. Sixteen human immunodeficiency virus-positive patients with AIDS-related complex who had been maintained on stable ZDV therapy for > or = 6 weeks were administered RBT concomitantly for 12 days. Eight patients received daily doses of 300 or 450 mg of RBT. Administration of ZDV was discontinued on day 13, and RBT was given alone for 3 additional days. Four patients receiving 450 mg of RBT discontinued treatment. Under steady-state ZDV and RBT dosing, safety and kinetics assessments were performed on day 13 (ZDV plus RBT) and day 16 (RBT alone). Kinetics on days 13 and 16 demonstrated that RBT (300 or 450 mg) was readily absorbed, with the time at which the plasma concentration was maximal (Tmax) ranging between 2.6 and 2.9 h. At these two doses, the mean steady-state maximal plasma concentrations (Cmax) were 250 and 430 ng/ml on day 13 and 245 and 458 ng/ml on day 16, respectively. RBT kinetics at the two doses were proportional and similar on the basis of estimates of the ratios of the areas under the concentration-time curves over the dosing interval from 0 to 24 h (AUC0-24) (450 mg/300 mg), which were 1.5 and 1.4 for days 13 and 16, respectively. No significant differences were apparent in the mean oral clearance (CLs/F) estimates (range, 1.60 to 1.77 liters/h/kg), which were dose independent and similar for the 2 assessment days, as was the urinary recovery of RBT and its 25-deacetyl metabolite. Low urinary recovery of 25-deacetyl RBT and an AUC metabolite/parent ratio of 0.1 suggest that there is minimal metabolism of RBT via the deacetylation pathway. For RBT, pooled mean (95% confidence interval) ratio (day 13/day 16) estimates for Cmax, Tmax, AUC0-24, and CLs/F were 1.07 (range, 0.77 to 1.38), 1.08 (0.89 to 1.27), 0.97 (0.82 to 1.13), and 1.09 (0.92 to 1.26), respectively. In addition, no significant changes in any of the major safety parameters were detected throughout the study. Therefore, it is concluded that coadministration of ZDV and RBT does not affect the pharmacokinetics and/or safety of RBT in human immunodeficiency virus-positive patients.

Miniature Kinematic Mirror Mount for UHV Service

A miniature kinematic mount allows adjustment of mirror pointing inside ultrahigh vacuum (UHV) by rotating finely threaded screws outside of vacuum. The mount assembly is less than 0.620 in. in diameter, so it fits through the standard tubing used with miniature conflat flanges. The mount is a point-iine-plane device with a sapphire ball at the point position, so that no lubrication is required in vacuum.

The reliability of interpretation of photoscreening results with the off PS-100 in Headstart preschool children

BACKGROUND

Photoscreening has emerged as one of the newest means of screening children to detect amblyogenic factors. In the preschool population, it is important to reliably screen children who are at risk for developing amblyopia. This research was undertaken to determine the reliability of the interpretation of photoscreening results in a Headstart preschool population.

METHODS

Fifty-four African-American children aged 3 to 5 years of age were examined using the MTI PS-100 photorefractor. Five health care professionals with no prior knowledge of photoscreening techniques were asked to perform independent, masked interpretations of a set of 54 Polaroid snapshots. Their interpretations followed a training session by a company consultant.

RESULTS

The kappa coefficient for reliability of interpretation between observers was 0.55. This kappa value indicates that there was moderate agreement between the observers when identifying amblyogenic conditions in a child.

CONCLUSIONS

Non-vision professionals using this device for the assessment of children will probably achieve only moderate levels of agreement on pass-fail decisions at first. Higher reliability reported previously by more experienced photoscreeners indicates that agreement could improve with advanced training, feedback regarding diagnostic findings, and experience. Methods to improve the technique, the device, or the training of the examiners are discussed.

A phase I dose-ranging safety and pharmacokinetics study of a novel oral thromboxane synthase inhibitor, FCE 22, 178

A 100- to 3200-mg dose range of FCE 22,178 was studied in this phase I single-dose escalation safety/kinetics study. After oral administration, a rapid drug absorptive phase and a biexponential disposition profile were observed. Mean estimates of the terminal elimination half-life of FCE 22,178, over the doses studied, ranged from 7.6 to 14.4 hours. A disproportionate increase in both maximum peak plasma concentration (Cmax) and area under the curve (AUC0-infinity) was noticed for doses higher than 400 mg. Mean estimates of systemic clearance (CLs/F) over the 100- to 400-mg doses were 0.053 to 0.064 L/hour/kg, and were significantly higher for the three higher dose levels. This nonlinearity appears to be related to the changes in oral bioavailability. Estimates of distribution volume (Vd, lambda z/F) for FCE 22,178 increased from 0.75 L/kg at the 100-mg dose to 3.00 L/kg at the 3200-mg dose, and renal clearance (CLr) also increased with dose. Both observations may be related to an increase in free fraction of FCE 22,178 at higher doses. Urinary excretion of unchanged drug averaged < 10% for all dose levels. The urinary excretion of the glucuronide metabolite (M1) averaged 41 to 70% for doses up to 400 mg, but diminished to 13% at the 3200-mg dose. The disposition of M1 appeared to be formation-rate limited. In addition, the ratio of the formation to the disposition clearance for M1 was relatively stable and apparently dose independent. No drug-related adverse experiences were observed over the studied dose range after single doses at FCE 22,178.

Anatomy of the flexor retinaculum

For an accurate definition of the anatomic limits of the carpal tunnel, 26 cadaver upper extremities were studied by gross (10), histologic (3), and radiographic (13) methods. The mean proximal limit of the central portion of the flexor retinaculum was 11 mm distal to the capitate-lunate joint, and the mean distal limit of the distal portion was 10 mm distal to the carpometacarpal joint of the third metacarpal. Carpal tunnel width at the hook of the hamate (20 mm) was significantly smaller than its proximal (24 mm) or distal (25 mm) extent. The flexor retinaculum extended from the distal aspect of the radius to the distal aspect of the base of the third metacarpal. We redefined the palmar boundary of the carpal tunnel to include three continuous segments of flexor retinaculum: the thin proximal segment composed of thickened deep investing fascia of the forearm; the transverse carpal ligament; and the distal portion of the flexor retinaculum, composed of an aponeurosis between the thenar and hypothenar muscles. In light of recent operative procedures that divide only the transverse carpal ligament, this study provides an anatomic basis for a more extensive release.

Rifabutin absorption in humans: relative bioavailability and food effect

The relative bioavailability of the capsule dose form (150 mg) and the effect of high-fat food were assessed in a randomized, three-way crossover trial of rifabutin in 12 healthy male volunteers. Each subject received a single 150 mg dose as a solution (treatment A, fasted) or a capsule with food (treatment B) and without food (treatment C), with a 2-week washout period. Serial plasma and urine samples were obtained for 168 and 48 hours, respectively, and rifabutin and its active metabolite, 25-O-deacetyl-rifabutin, quantitated by a validated HPLC procedure. The mean +/- SD maximum concentration for rifabutin in plasma was 238 +/- 65, 156 +/- 52, and 188 +/- 50 ng/ml, time to reach peak concentration was 2.5 +/- 0.4, 5.4 +/- 1.6, and 3.0 +/- 1.1 hours, and the area under the plasma concentration-time curve from zero to infinity [AUC(0-infinity)] was 2989 +/- 726, 2640 +/- 891, and 2516 +/- 601 ng.hr/ml for the solution and the capsule during the fed and fasted states, respectively. Percentage of dose excreted in the urine as unchanged rifabutin was 11.0% +/- 2.4%, 11.4% +/- 4.9%, and 9.1% +/- 2.1% for treatments A, B, and C, respectively. The corresponding AUC(0-infinity) values for the equiactive metabolite 25-O-deacetyl-rifabutin, were 400 +/- 184, 361 +/- 187, and 298 +/- 102 ng.hr/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Establishment of carpal contents/canal ratio by means of magnetic resonance imaging

Magnetic resonance imaging (MRI) was used to determine cross-sectional areas and volumes of carpal canals and carpal canal contents in five cadaver specimens in an assessment of the reliability of MRI for establishing contents/canal ratios. Volumes of the carpal canals and their contents were accurately calculated from MRI with a previously described correction factor (0.8161) for carpal tunnel volumes and a calculated correction factor (1.078) for carpal tunnel contents volume. There was no significant difference between laboratory-measured or MRI-calculated ratios from either volumes (p = 0.86) or surface areas (p greater than 0.79). Cross-sectional area contents/canal ratios were significantly higher (p = 0.0001) at the level of the distal aspect of the hook of the hamate (0.54) as compared with those at the level of the distal radial styloid (0.42) and proximal metacarpals (0.44). MRI provides an effective and reliable means of determining contents/canal ratios from both cross-sectional area and volume calculations.

The carpal tunnel as a compartment. An anatomic perspective

Previously, patients with carpal tunnel syndrome have exhibited an elevated carpal tunnel pressure compared with that of control subjects. The etiology and maintenance of this pressure remains controversial, however. Both the open- and closed-compartment theories have their own advocates, although the closed-compartment theory has no apparent anatomic support.

Tips of the trade. Dacron core suture via suture-assist device. A technique for flexor tendon repair

This article introduces a technique of tendon repair using large-gauge dacron core sutures placed by a suture-assist device. Tensile strengths of the repair on preserved human tendons averaged 44.1 Newtons, compared with 29.8 Newtons for repairs with a modified Kessler technique. The technique shows promise as an alternative method for flexor tendon repair.

A sensitive and specific procedure for quantitation of ADR-529 in biological fluids by high-performance liquid chromatography (HPLC) with column switching and amperometric detection

An HPLC method using electrochemical detection (ED) has been validated for the determination of ADR-529 in plasma and urine using ICRF-192 as an internal standard (IS). Prior to storage and quantitation, both plasma and urine samples require acid stabilization. Acidified plasma samples were prepared for HPLC using a two column solid-phase extraction (SPE). An aliquot of buffered plasma (i.e., pH 6-7) was first deproteinated and desalted on a C-18 SPE column. The analytes were then eluted onto a C-8 SPE column where retention and selective cleanup were achieved in the cation-exchange mode via silanol interactions. Acidified urine samples were diluted in acetonitrile prior to injection. The HPLC system for plasma and urine samples employed two narrow-bore silica columns used in the weak cation-exchange mode and separated by a switching valve. To prohibit late-eluting peaks from passivating the glassy carbon working electrode, a heart-cut containing ADR-529 and the IS was vented from the first silica column to the second using an automated switching valve. Amperometric detection at an oxidation potential of +1050 mV vs a Ag/AgNO3 reference electrode was used. Linearity was validated between 5 and 500 ng/ml in plasma and between 2 and 100 micrograms/ml in urine. Imprecision and percentage bias were typically less than 10% for both plasma and urine controls throughout their respective dynamic ranges. The absolute recoveries for ADR-529 and the IS from plasma were greater than 95%. This method is being successfully applied to the pharmacokinetic/dynamic evaluation of ADR-529 in animals and humans.

A sensitive method for quantitation of rifabutin and its desacetyl metabolite in human biological fluids by high-performance liquid chromatography (HPLC)

Sensitive HPLC-UV methodology has been developed and validated for quantitating rifabutin, an antimycobacterial, and its 25-desacetyl metabolite, LM-565, in human plasma and urine. The HPLC separation for both plasma and urine samples was performed on an ODS, 5-microns, reverse-phase column (25 cm x 4.6-cm ID) using a mobile phase of acetonitrile/0.05 M potassium phosphate, pH 4.2, with triethylamine, (38:61.5:0.5, v/v), at a flow rate of 1.0 ml/min. The separation eluate was monitored by absorbance at 275 nm. Plasma samples (1 ml) were spiked with an internal standard (medazepam), buffered at pH 7.4 and extracted with 80:20 (v/v) hexane:ethyl acetate, and then back extracted with acidified water (0.05 M H3PO4). Linearity was established between 5.0-800 and 2.5-400 ng/ml for rifabutin and LM-565, respectively. Intraday imprecision for rifabutin and LM-565 plasma quality controls prepared at 7.3 and 3.2 ng/ml, respectively, was less than 15% relative standard deviation (RSD). Absolute recovery for parent drug and metabolite, from plasma, was greater than 90% throughout the respective dynamic ranges and greater than 70% for medazepam. Urine samples (1 ml) were acidified with 50 microliters of 3.6 M H2SO4 and diluted with 0.1 M ammonium acetate. Linearity was established between 100 and 5000 ng/ml for both rifabutin and LM-565. Intraday imprecision for a urine control at 200 ng/ml was less than or equal to 12% RSD for either component. The method is currently being used to support Phase I kinetics program for rifabutin in prophylaxis of MAC infection of AIDS patients. Application of this method to a bioavailability assessment is presented.

Quantitation of a novel antiemetic (ADR-851) in plasma and urine by reversed-phase high-performance liquid chromatography with fluorescence detection

A sensitive and specific bioanalytical method for quantitation of a novel antiemetic (ADR-851) in plasma and urine has been developed and validated. The drug and internal standard (metoclopramide) are extracted from the plasma matrix by solid-phase extraction on cyanopropyl bonded-phase columns. After extraction, samples are separated by isocratic reversed-phase high-performance liquid chromatography. The parent drug, internal standard and a yet unidentified metabolite are detected by fluorescence. The method requires 1.0 ml of plasma or 0.1 ml of urine and has a lower limit of quantitation of 2 ng/ml with 10.9% relative standard deviation (R.S.D.). Method linearity has been established over a 2-800 ng/ml range when 1.0 ml of plasma is used. The intra- and inter-day imprecisions for the method are typically better than 6% and 11% R.S.D., respectively, in both plasma and urine over the entire dynamic range. The pooled estimate of bias is less than 5% and attests to the excellent accuracy.

Transfer of sensibility in the hand: a new method to restore sensibility in ulnar nerve palsy with use of microsurgical digital nerve translocation

We describe a technique of translocation of a functioning proximal digital nerve into a non-functional distal digital nerve. Seventeen cases of digital nerve translocation have been done, thirteen were done for treatment of ulnar nerve palsy. Three patients were less than six months after operation and one had died, leaving thirteen available for follow-up. The average length of follow-up is seventy-eight months. Outcome was assessed objectively by functional sensory testing and subjectively by questionnaire. Ten (85%) of twelve of those tested had return of two-point discrimination. In all cases proprioception and protective sensibility were restored to the affected digit.

Determination of nicorandil in plasma using high-performance liquid chromatography with photoconductivity and ultraviolet detection. Application to pre-clinical pharmacokinetics in beagle dogs

A sensitive and precise method for the determination of nicorandil, a new anti-anginal medication, is reported. The method involves solid-phase extraction of the drug and internal standard using Bond-Elut C18 extraction columns, reversed-phase high-performance liquid chromatography on a Zorbax-Phenyl column and detection with photoconductivity and ultraviolet detection in series. Photoconductivity, performed with the Tracor 965 photoconductivity detector, provided a limit of detection of 2 ng/ml in plasma (between-day coefficient of variation of 15%) but the linear range of response was limited to only about 100 ng/ml. Ultraviolet detection in series with the photoconductivity detector extended the linear range of the analytical system to 1000 ng/ml (coefficient of variation 4.4%). The utility of the method is demonstrated in a dog pharmacokinetic study in which a 5-mg intravenous dose was compared to a 10-mg oral solution dose in six beagle dogs. The oral solution was absorbed rapidly, achieving an average maximum concentration of 857 ng/ml in 11.2 min. The absolute bioavailability of nicorandil in dogs in this study was determined to be 84.2%.

Treatment of upper extremity reflex sympathetic dystrophy with joint stiffness using sympatholytic Bier blocks and manipulation

Twenty patients with reflex sympathetic dystrophy involving the upper extremity with associated joint stiffness were treated by manipulation under Bier blocks composed of lidocaine, methylprednisolone, and reserpine or guanethidine. Depending on the patients' response, repeat blocks were performed at 48- to 72-hour intervals. Range of motion in the affected joints (primarily the hand and wrist) improved from a pre-block mean of 46% to 81% of normal following the blocks. Patients also reported an 80% mean improvement in their pain. The treatment of advanced reflex sympathetic dystrophy using joint manipulation under sympatholytic Bier blocks appears to be a safe and effective method of treatment.

Scapholunate instability following ganglion cyst excision. A case report

Complications following ganglion cyst excision include a 3%-50% recurrence rate, wrist stiffness, infection, neuroma formation, and keloid formation. Scapholunate instability is almost never seen as a complication of ganglion excision. Scapholunate instability occurred following excision of a dorsal ganglion in the wrist of a 38-year-old man.

Web space reconstruction with a M-V flap

An operative technique for the construction of a supple and broad commissure in syndactyly and web contracture release is introduced. The technique is based on a M-V flap framework. Sixty-three flaps were done in 33 patients who were followed-up for an average of 19 months. Excellent results were obtained in 90% of the cases. There were no neurologic or vascular complications in any of these cases. The versatility of this method has allowed its use in the majority of our cases that necessitated web release or web space reconstruction.

Biomechanical and clinical evaluation of the expandable intramedullary fixation device

The use of an expandable intramedullary device for internal fixation of metacarpal or phalangeal bones is described. The device is applicable to transverse fractures, short oblique fractures, or transverse osteotomies. The device consists of a cylindrical apparatus made of titanium that allows collapse in the circumferential diameter. It is introduced into the medullary canal in its collapsed state, and on release expands to its normal diameter in the canal with the fracture reduced over it. A biomechanical evaluation compared the stability of this device with other commonly employed fixation methods. A retrospective review is presented of the first 43 patients in whom the device was implanted.

Treatment of carpal tunnel syndrome by members of the American Society for Surgery of the Hand: results of a questionnaire

Carpal tunnel syndrome is one of the most common problems seen by the hand surgeon. In spite of its frequent occurrence there are several aspects of its treatment that remain controversial. A survey of the members of the American Society for Surgery of the Hand determined whether a consensus exists concerning the treatment of carpal tunnel syndrome among surgeons who regularly treat hand problems.

Expandable intramedullary device for treatment of fractures in the hand

Because the hand tolerates disuse so poorly, the beginning of early motion following fractures is important in achieving early restoration of function. This report concerns the use of a unique, expandable intramedullary device for internal fixation of metacarpal or phalangeal shaft fractures that renders enough intrinsic stability that motion may be started early without fear of loss of reduction. The device is applicable for transverse or short oblique fractures and consists of a cylindrical apparatus made of titanium that allows for collapse in the circumferential diameter. It is introduced into the medullary canal in its collapsed state, and then is released to allow reexpansion into its normal diameter in the canal with the fracture reduced over it. This gives excellent fixation and affords stability approaching that of normal bone. Minimal postoperative immobilization is needed and early restoration of motion is possible. The device may also be used to immobilize metacarpal bones or phalanges following osteotomies, and it appears to be excellent for fixation of the bone in digits to be replanted. No complications have occurred in the reported series.

The tenon method of small joint arthrodesis in the hand

A technique for arthrodesis of small joints of the hand is described that uses a tenon to secure apposition that has good intrinsic stability as well as a large surface area of cancellous bony contact. A minimum of postoperative immobilization is required. The tenon arthrodesis method has been employed in 85 joints. The literature shows pseudoarthrosis rates of 0 to 33%. This technique had a 2.3% failure rate that compares favorably with those in other published series.

Infections of the hand

The unique anatomic arrangements in the hand make possible rapid extension of infections through synovial-lined spaces if abscesses are not drained and pressure is allowed to build up. Adequate knowledge of these anatomic features and of routes for surgical drainage is mandatory if one is to give adequate management of hand infections. Localized processes, such as paronychia, felon, and human bite infections also require special insight for adequate treatment.

High-compression injection injuries to the hand

The importance of a specific effect of various agents injected into the hand cannot be overemphasized, since the outpouring of inflammatory edema fluid as a response to the more sclerotic solutions leads to tamponade and occlusion of digital vessels. Moreover, it has been shown that the vascular insufficiency is further increased by actual necrosis of small vessel walls caused by these solutions, which coagulate the protein of the arteriolar and arterial wall. The pathologic physiology is described, which indicates that the usual case of high-compression injection of foreign material into the hand develops severe and sometimes catastrophic consequences related to the tamponade effect occurring from the compression force, the quantity of material injected, and the subsequent outpouring of inflammatory edema fluid occasioned by the chemical irritation of these substances within the tissues. Based upon these findings, it has been pointed out that early treatment of these injuries is mandatory, with adequate incision along diagonal lines on the palmar surface of the hand made with the idea of decompressing the tamponade effect on the digital vessels as well as evacuation of the foreign material. Careful cleansing of the surrounding tissues to remove extensions of the material from the central mass is important. Finally, the postoperative measures, the late treatment procedures, and the rehabilitative surgical procedures have been described.

Injuries of the cervical spine in high school wrestling

Severe injuries to the cervical spine and spinal cord have been widely reported from many causes: automobile accidents, diving mishaps, falls, and contact sports. This paper concerns three young men who sustained severe trauma to the cervical spine and spinal cord during high school wrestling. Certain head-holds are prone to cause such injuries. Their tetraparesis and tetraplegia were reversed by reducing the fracture-dislocation and internal stabilization, in one case by decompressive laminectomy when no bony disruption was encountered. Their recoveries were satisfactory, but prevention of these cervical injuries may be accomplished by elimination of the more dangerous holds in wrestling.

Digital nerve-grafting for traumatic defects. Use of the lateral antebrachial cutaneous nerve

We used segments of the lateral antebrachial cutaneous nerve to graft defects in forty-two digital nerves in thirty-five patients. Age was a more important prognostic indicator for functional sensibility than either the length of the nerve graft or the time-interval from injury to grafting. The younger patients did better. A battery of eight tests was used to determine functional sensibility scores. All patients improved and 40 per cent had completely normal sensibility.

The lateral antebrachial cutaneous nerve as a highly suitable autograft donor for the digital nerve

The lateral antebrachial cutaneous and digital nerves were compared by a histomorphometric method in each patient from a series of patients in whom a digital nerve was grafted with the lateral antebrachial cutaneous nerve as donor. Statistical analysis by the paired Student's test of paired data sets from all patients showed that there was no significant difference between the two nerves in regard to the following parameters: fascicular area, area of the entire nerve bundle, and percent of the nerve bundle occupied by the actual nerve fascicles. These data, together with other observations reported here, strongly support the hypothesis that the lateral antebrachial cutaneous nerve closely resembles the original fascicular pattern of the digital nerve and is, therefore, a highly suitable donor for the digital nerve.

Multifocal neurilemmomas of median and ulnar nerves of the same extremity--case report

A 49-year-old man had multiple tumors in both the median and ulnar nerves in the same extremity, all histologically typical neurilemmomas. Removal was accomplished under high-power magnification, preserving individual fascicles and sensory and motor function.

Cerebellar astrocytoma invading the musculature and soft tissues of the neck. Case report

A case of cerebellar astrocytoma with unusual growth pattern in an 8-year-old boy is reported. The tumor had some histological hallmarks of malignancy (focally high cellularity, mitotic figures, necroses, and calcifications) and, 17 months after subtotal removal, recurred as a nuchal mass in the area of the incision, infiltrating first the skeletal musculature and later other soft tissues of the neck, including lymph nodes. Although cerebellar astrocytomas may recur locally and some may even seed through the cerebrospinal fluid, this is the first reported case of a tumor of this group to infiltrate skeletal muscle and other soft tissues of the neck. The patient underwent five operations to relieve the cervical organs from pressure.