Evaluating the Ability of Brachial Plexus-Injured Patients to Control an Externally Powered (Myoelectric) Hand Prosthesis

BACKGROUND

Restoration of hand function after traumatic brachial plexus injury (BPI) remains a formidable challenge. Traditional methods such as nerve or free muscle transfers yield suboptimal results. Advancements in myoelectric prostheses, characterized by novel signal acquisition and improved material technology, show promise in restoring functional grasp. This study evaluated the ability of adults with a BPI injury to control an externally powered prosthetic hand using nonintuitive signals, simulating the restoration of grasp with a myoelectric prosthesis. It also assessed the effectiveness of a comprehensive multidisciplinary evaluation in guiding treatment decisions.

METHODS

A multidisciplinary brachial plexus team assessed adults with compromised hand function due to BPI. The feasibility of amputation coupled with fitting of a myoelectric prosthesis for grasp reconstruction was evaluated. Participants' ability to control a virtual or model prosthetic hand using surface electromyography (EMG) as well as with contralateral shoulder motion-activated linear transducer signals was tested. The patient's input and injury type, along with the information from the prosthetic evaluation, were used to determine the reconstructive plan. The study also reviewed the number of participants opting for amputation and a myoelectric prosthetic hand for grasp restoration, and a follow-up survey was conducted to assess the impact of the initial evaluation on decision-making.

RESULTS

Of 58 subjects evaluated, 47 (81%) had pan-plexus BPI and 42 (72%) received their initial assessment within 1 year post-injury. Forty-seven patients (81%) could control the virtual or model prosthetic hand using nonintuitive surface EMG signals, and all 58 could control it with contralateral uniscapular motion via a linear transducer and harness. Thirty patients (52%) chose and pursued amputation, and 20 (34%) actively used a myoelectric prosthesis for grasp. The initial evaluation was informative and beneficial for the majority of the patients, especially in demonstrating the functionality of the myoelectric prosthesis.

CONCLUSIONS

The study indicates that adults with traumatic BPI can effectively operate a virtual or model myoelectric prosthesis using nonintuitive control signals. The simulation and multidisciplinary evaluation influenced informed treatment choices, with a high percentage of patients continuing to use the myoelectric prostheses post-amputation, highlighting its long-term acceptance and viability.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The Role of Amputation and Myoelectric Prosthetic Fitting in Patients with Traumatic Brachial Plexus Injuries

BACKGROUND

A cohort of patients with traumatic brachial plexus injuries (BPIs) underwent elective amputation following unsuccessful surgical reconstruction or delayed presentation. The results of amputation with and without a myoelectric prosthesis (MEP) using nonintuitive controls were compared. We sought to determine the benefits of amputation, and whether fitting with an MEP was feasible and functional.

METHODS

We conducted a retrospective review of patients with BPI who underwent elective upper-extremity amputation at a single institution. Medical records were reviewed for demographics, injury and reconstruction details, amputation characteristics, outcomes, and complications. Prosthesis use and MEP function were assessed. The minimum follow-up for clinical outcomes was 12 months.

RESULTS

Thirty-two patients with BPI and an average follow-up of 53 months underwent elective amputation between June 2000 and June 2020. Among the cases were 18 transhumeral amputations, 12 transradial amputations, and 2 wrist disarticulations. There were 29 pan-plexus injuries, 1 partial C5-sparing pan-plexus injury, 1 lower-trunk with lateral cord injury, and 1 lower-trunk injury. Amputation occurred, on average, at 48.9 months following BPI and 36.5 months following final reconstruction. Ten patients were fitted for an MEP with electromyographic signal control from muscles not normally associated with the intended function (nonintuitive control). Average visual analog scale pain scores decreased post-amputation: from 4.8 pre-amputation to 3.3 for the MEP group and from 5.4 to 4.4 for the non-MEP group. Average scores on the Disabilities of the Arm, Shoulder and Hand questionnaire decreased post-amputation, but not significantly: from 35 to 30 for the MEP group and from 43 to 40 for the non-MEP group. Patients were more likely to be employed following amputation than they were before amputation. No patient expressed regret about undergoing amputation. All patients in the MEP group reported regular use of their prosthesis compared with 29% of patients with a traditional prosthesis. All patients in the MEP group demonstrated functional terminal grasp/release that they considered useful.

CONCLUSIONS

Amputation is an effective treatment for select patients with BPI for whom surgical reconstruction is unsuccessful. Patients who underwent amputation reported decreased mechanical pain, increased employment rates, and a high rate of satisfaction following surgery. In amputees with sufficient nonintuitive electromyographic signals, MEPs allow for terminal grasp/release and are associated with high rates of prosthesis use.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Temporal characterization of flowback and produced water quality from a hydraulically fractured oil and gas well

This study examined water quality, naturally-occurring radioactive materials (NORM), major ions, trace metals, and well flow data for water used and produced from start-up to operation of an oil and gas producing hydraulically-fractured well (horizontal) in the Denver-Julesburg (DJ) Basin in northeastern Colorado. Analysis was conducted on the groundwater used to make the fracturing fluid, the fracturing fluid itself, and nine flowback/produced water samples over 220days of operation. The chemical oxygen demand of the wastewater produced during operation decreased from 8200 to 2500mg/L, while the total dissolved solids (TDS) increased in this same period from 14,200 to roughly 19,000mg/L. NORM, trace metals, and major ion levels were generally correlated with TDS, and were lower than other shale basins (e.g. Marcellus and Bakken). Although at lower levels, the salinity and its origin appear to be the result of a similar mechanism to that of other shale basins when comparing Cl/Br, Na/Br, and Mg/Br ratios. Volumes of returned wastewater were low, with only 3% of the volume injected (11millionliters) returning as flowback by day 15 and 30% returning by day 220. Low levels of TDS indicate a potentially treatment-amenable wastewater, but low volumes of flowback could limit onsite reuse in the DJ Basin. These results offer insight into the temporal water quality changes in the days and months following flowback, along with considerations and implications for water reuse in future hydraulic fracturing or for environmental discharge.

Abstract P3-07-20: Biological functions of ERβ in triple negative breast cancer and its utility as a novel therapeutic drug target

Background: Triple negative breast cancer (TNBC) accounts for approximately 20% of all breast cancer diagnoses. It is the most aggressive form of breast cancer and clinical management is problematic due to lack of available targeted therapies. We have shown that approximately 30% of all TNBCs express estrogen receptor beta (ERβ), a ligand binding transcription factor, and a potential drug target for patients with this form of the disease.

Methods: Using novel ERβ-expressing TN cell lines developed in our laboratory, we assessed the impacts of ERβ on proliferation, invasion, migration, and alterations in cell cycle progression following estrogen and ERβ-specific agonist treatment. We also characterized the ERβ transcriptome and cistrome in these models through microarray and ChIP-Seq, respectively. Finally, we determined the tumoral response of cell line xenografts and PDXs treated with 17β-estradiol.

Results: We found that both estrogen and multiple ERβ-specific agonists elicit significant anti-tumor effects in ERβ+ TNBC cell lines and tumor xenografts. Activation of ERβ with estrogen and ERβ-specific agonists resulted in inhibition of cell proliferation primarily through a G1/S phase cell cycle arrest. Substantial reductions in cell migration and invasion were also observed following treatment. Microarray studies revealed that ERβ differentially regulated the expression of approximately 1000 genes following estrogen treatment. Of these genes, the most striking effects were observed in a family of small secreted cysteine protease inhibitors known as cystatins, which were highly induced following ERβ activation. ChIP-Seq and ChIP-PCR identified ERβ binding sites in the promoter region of each cystatin and demonstrated ERβ-mediated alterations in chromatin marks and recruitment of PolII around these promoters. We found that cystatins directly interact with TGFβ receptor 2 (TGFβR2) and block downstream TGFβ ligand-mediated activation of the canonical signaling pathway. Depletion of cystatins from conditioned media or through siRNA-mediated silencing reduced the ability of ERβ to elicit these anti-tumor effects. In vivo, estrogen treatment of mice harboring ERβ+ TNBC cell line xenografts or PDXs resulted in increased tumoral expression and serum levels of cystatins, and suppressed tumor growth.

Conclusions: Our data demonstrated that estrogen and ERβ-specific agonists elicit anti-cancer effects in ERβ+ TNBC, both in vitro and in vivo. These effects are partially mediated by cystatins which can interact with, and inhibit, canonical TGFβ signaling, a pathway known to drive TNBC progression. Given the lack of targeted therapies for TNBC patients, the present data suggests that estrogen or ERβ-specific agonists offer a novel approach to manage this subset of patients.

Citation Format: Reese JM, Bruinsma ES, Suman VJ, Nelson AW, Chernukhin I, Carroll JS, Ingle JN, Goetz MP, Hawse JR. Biological functions of ERβ in triple negative breast cancer and its utility as a novel therapeutic drug target [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-07-20.

Polonium-210 accumulates in a lake receiving coal mine discharges-anthropogenic or natural?

Coal is an integral part of global energy production; however, coal mining is associated with numerous environmental health impacts. It is well documented that coal-mine waste can contaminate the environment with naturally-occurring radionuclides from the uranium-238 (²³⁸U) decay series. However, the behavior of the final radionuclide in the ²³⁸U-series, i.e., polonium-210 (²¹⁰Po) arising from coal-mine waste-water discharge is largely unexplored. Here, results of a year-long (2014-2015) field study, in which the concentrations of ²¹⁰Po in sediments and surface water of a lake that receives coal-mine waste-water discharge in West Virginia are presented. Initial measurements identified levels of ²¹⁰Po in the lake sediments that were in excess of that which could be attributed to ambient U-series parent radionuclides; and were indicative of discharge site contamination of the lake ecosystem. However, control sediment obtained from a similar lake system in Iowa (an area with no coal mining or unconventional drilling) suggests that the levels of ²¹⁰Po in the lake are a natural phenomenon; and are likely unrelated to waste-water treatment discharges. Elevated levels of ²¹⁰Po have been reported in lake bottom sediments previously, yet very little information is available on the radioecological implications of ²¹⁰Po accumulation in lake bottom sediments. The findings of this study suggest that (Monthly Energy Review, 2016) the natural accumulation and retention of ²¹⁰Po in lake sediments may be a greater than previously considered (Chadwick et al., 2013) careful selection of control sites is important to prevent the inappropriate attribution of elevated levels of NORM in lake bottom ecosystems to industrial sources; and (Van Hook, 1979) further investigation of the source-terms and potential impacts on elevated ²¹⁰Po in lake-sediment ecosystems is warranted.

Partitioning of naturally-occurring radionuclides (NORM) in Marcellus Shale produced fluids influenced by chemical matrix

Naturally-occurring radioactive materials (NORM) associated with unconventional drilling produced fluids from the Marcellus Shale have raised environmental concerns. However, few investigations into the fundamental chemistry of NORM in Marcellus Shale produced fluids have been performed. Thus, we performed radiochemical experiments with Marcellus Shale produced fluids to understand the partitioning behavior of major radioelements of environmental health concern (uranium (U), thorium (Th), radium (Ra), lead (Pb), and polonium (Po)). We applied a novel radiotracer, (203)Pb, to understand the behavior of trace-levels of (210)Pb in these fluids. Ultrafiltration experiments indicated U, Th, and Po are particle reactive in Marcellus Shale produced fluids and Ra and Pb are soluble. Sediment partitioning experiments revealed that >99% of Ra does not adsorb to sediments in the presence of Marcellus Shale produced fluids. Further experiments indicated that although Ra adsorption is related to ionic strength, the concentrations of heavier alkaline earth metals (Ba, Sr) are stronger predictors of Ra solubility.

Understanding the Radioactive Ingrowth and Decay of Naturally Occurring Radioactive Materials in the Environment: An Analysis of Produced Fluids from the Marcellus Shale

BACKGROUND

The economic value of unconventional natural gas resources has stimulated rapid globalization of horizontal drilling and hydraulic fracturing. However, natural radioactivity found in the large volumes of "produced fluids" generated by these technologies is emerging as an international environmental health concern. Current assessments of the radioactivity concentration in liquid wastes focus on a single element-radium. However, the use of radium alone to predict radioactivity concentrations can greatly underestimate total levels.

OBJECTIVE

We investigated the contribution to radioactivity concentrations from naturally occurring radioactive materials (NORM), including uranium, thorium, actinium, radium, lead, bismuth, and polonium isotopes, to the total radioactivity of hydraulic fracturing wastes.

METHODS

For this study we used established methods and developed new methods designed to quantitate NORM of public health concern that may be enriched in complex brines from hydraulic fracturing wastes. Specifically, we examined the use of high-purity germanium gamma spectrometry and isotope dilution alpha spectrometry to quantitate NORM.

RESULTS

We observed that radium decay products were initially absent from produced fluids due to differences in solubility. However, in systems closed to the release of gaseous radon, our model predicted that decay products will begin to ingrow immediately and (under these closed-system conditions) can contribute to an increase in the total radioactivity for more than 100 years.

CONCLUSIONS

Accurate predictions of radioactivity concentrations are critical for estimating doses to potentially exposed individuals and the surrounding environment. These predictions must include an understanding of the geochemistry, decay properties, and ingrowth kinetics of radium and its decay product radionuclides.

Monitoring radionuclides in subsurface drinking water sources near unconventional drilling operations: a pilot study

Unconventional drilling (the combination of hydraulic fracturing and horizontal drilling) to extract oil and natural gas is expanding rapidly around the world. The rate of expansion challenges scientists and regulators to assess the risks of the new technologies on drinking water resources. One concern is the potential for subsurface drinking water resource contamination by naturally occurring radioactive materials co-extracted during unconventional drilling activities. Given the rate of expansion, opportunities to test drinking water resources in the pre- and post-fracturing setting are rare. This pilot study investigated the levels of natural uranium, lead-210, and polonium-210 in private drinking wells within 2000 m of a large-volume hydraulic fracturing operation--before and approximately one-year following the fracturing activities. Observed radionuclide concentrations in well waters tested did not exceed maximum contaminant levels recommended by state and federal agencies. No statistically-significant differences in radionuclide concentrations were observed in well-water samples collected before and after the hydraulic fracturing activities. Expanded monitoring of private drinking wells before and after hydraulic fracturing activities is needed to develop understanding of the potential for drinking water resource contamination from unconventional drilling and gas extraction activities.

A simple-rapid method to separate uranium, thorium, and protactinium for U-series age-dating of materials

Uranium-series dating techniques require the isolation of radionuclides in high yields and in fractions free of impurities. Within this context, we describe a novel-rapid method for the separation and purification of U, Th, and Pa. The method takes advantage of differences in the chemistry of U, Th, and Pa, utilizing a commercially-available extraction chromatographic resin (TEVA) and standard reagents. The elution behavior of U, Th, and Pa were optimized using liquid scintillation counting techniques and fractional purity was evaluated by alpha-spectrometry. The overall method was further assessed by isotope dilution alpha-spectrometry for the preliminary age determination of an ancient carbonate sample obtained from the Lake Bonneville site in western Utah (United States). Preliminary evaluations of the method produced elemental purity of greater than 99.99% and radiochemical recoveries exceeding 90% for U and Th and 85% for Pa. Excellent purity and yields (76% for U, 96% for Th and 55% for Pa) were also obtained for the analysis of the carbonate samples and the preliminary Pa and Th ages of about 39,000 years before present are consistent with (14)C-derived age of the material.

Nitric oxide produced by cytochrome c oxidase helps stabilize HIF-1α in hypoxic mammalian cells

The mitochondrial respiratory chain has been reported to play a role in the stabilization of HIF-1α when mammalian cells experience hypoxia, most likely through the generation of free radicals. Although previous studies have suggested the involvement of superoxide catalyzed by complex III more recent studies raise the possibility that nitric oxide (NO) catalyzed by cytochrome c oxidase (Cco/NO), which functions in hypoxic signaling in yeast, may also be involved. Herein, we have found that HEK293 cells, which do not express a NOS isoform, possess Cco/NO activity and that this activity is responsible for an increase in intracellular NO levels when these cells are exposed to hypoxia. By using PTIO, a NO scavenger, we have also found that the increased NO levels in hypoxic HEK293 cells help stabilize HIF-1α. These findings suggest a new mechanism for mitochondrial involvement in hypoxic signaling in mammalian cells.

The relationship between serum creatinine and estimated glomerular filtration rate: implications for clinical practice

INTRODUCTION

A new classification of chronic kidney disease (CKD) has been widely adopted that stratifies patients into 5 'stages' according to estimated glomerular filtration rate (eGFR). In adults the most commonly used formulae to calculate eGFR are the Cockcroft and Gault (C and G) and Modification of Diet in Renal Disease (MDRD) formulae. The UK Renal Association has recommended calculation of MDRD eGFR to screen for reduced kidney function in primary and secondary care.

AIM

The aim of this study was to explore the implication of using these predictive formulae.

METHODS

We searched for patients currently attending a renal clinic who have ever had a serum creatinine (SCr) of exactly 100 micromol/L, 150 micromol/L or 200 micromol/L. The C and G and MDRD eGFRs corresponding to that SCr were calculated. The proportion of patients in each stage of the CKD classification was determined.

RESULTS

For a SCr of 100 micromol/L mean eGFR was 86.5 ml/min (range 31.0 - 192.8) by C and G and 63.8 ml/min (range 39.7 - 99.9) by MDRD (p < 0.0001; t-test of mean). For SCr 150 micromol/L mean eGFR was 51.7 ml/min (18.0 - 110.4) by C and G and 38.0 ml/min (20.7 - 54.8) by MDRD (p < 0.0001). For SCr of 200 micromol/L mean eGFR was 34.4 ml/min (12.6 - 89.5) by C and G and 27.3 ml/min (16.7 - 41.3) by MDRD (p < 0.0001). Using MDRD eGFR 46.5% patients with a SCr of 100 micromol/L have stage 3 CKD (GFR 30-60 ml/min) and all patients with a SCr of 150 micromol/L or 200 micromol/L have CKD 3 or worse. 8.6% of males with SCr 100 micromol/L had stage 3 CKD or worse compared with 86.8% females. 70.2% patients > 65 years old with SCr 100 micromol/L had stage 3 CKD.

CONCLUSIONS

Targeted screening of patients at-risk for CKD will identify a large number of patients who require management of CKD and potential referral to nephrology services even at levels of SCr regarded as 'normal' or mildly.

Identity of Saccharomyces cerevisiae tRNA(Trp) is not changed by an anticodon mutation that creates an amber suppressor

A C35-->T mutation in an Escherichia coli tRNA(Trp) gene creates an amber suppressor which efficiently inserts glutamine in response to UAG codons in vivo (Soll, L., and Berg, P. (1969) Nature 223, 1340-1342). We have introduced the same change in a yeast tRNA(Trp) gene and demonstrated that the tRNA acts as an efficient amber suppressor in vivo. Amino acid sequence analyses were performed on chitinase produced by cells carrying the corresponding gene with a UAG codon at position 8 of the mature protein plus the mutant tRNA(Trp) gene. In contrast to comparable experiments with E. coli, tryptophan is inserted at a frequency > or = 80% by the yeast suppressor tRNA(Trp). Furthermore, in vitro charging experiments with the mutant tRNA(Trp) reveal no detectable increase in glutamine acceptor activity results from the C35-->T transition. The identity elements in E. coli tRNA(Gln) are well characterized (Jahn, M., Rogers, J., and Soll, D. (1991) Nature 352, 258-260). Sequence comparisons of the tRNA(Trp) and tRNA(Gln) molecules from E. coli reveal that the amber suppressor tRNA(Trp) has four of five identity elements required for glutaminyl-tRNA synthetase recognition. A similar comparison in the yeast system shows only two of the five potential identity elements are present. We conclude that, in spite of substantial structural similarities between yeast and E. coli aminoacyl-tRNA synthetases, fundamental differences can exist with regard to tRNA recognition.

A Comparison of Surgical Training with Live Anesthetized Dogs and Cadavers

Cadavers were compared with live anesthetized dogs for their effectiveness as models for surgical training of veterinary medical students. One group of students was trained using cadavers, and a peer group was trained using live anesthetized dogs. Both groups then performed an intestinal anastomosis using a live subject. The time to completion of the procedure was recorded. The anastomoses and celiotomy closures were evaluated. Each anastomosis was isolated and pressure tested. Reviewers blindly scored each surgical team's performance based on actual inspection of the surgical site and on viewing videotapes of the procedure. The participants' attitudes toward the use of live animals in teaching and research were documented before and after training. No statistically significant differences could be detected between the two groups. The results suggest that some substitution of cadavers for live dogs in surgical training might be feasible.

Exocrine pancreatic function following intraoperative irradiation of the canine pancreas

Twenty-four beagles received intraoperative irradiation (IORT) with 6 meV electrons to the pancreas and the duodenum. Intraoperative irradiation doses of 17.5 to 40 Gy were given. Billroth II gastrojejunostomy was done to bypass the irradiated duodenum. Six control dogs received only the Billroth II surgery. Two weeks postoperatively, irradiated dogs were given 50 Gy of 6 MV X radiation (external-beam radiation [EBRT]) to the pancreas and duodenum in 2 Gy fractions over a 5-week period. Dogs were monitored clinically and exocrine pancreatic function was evaluated using an N-benzoyl-l-tyrosyl-para-aminobenzoic acid (BT-PABA) test between 3 and 135 days postoperatively. Necropsies were performed on the dogs at 135 days postoperatively. The degree of gross pancreatic atrophy in the irradiated group was dose related. The mean percentage of normal acinar cells correlated with IORT doses and para-aminobenzoic acid (PABA) values (P less than 0.1). Weight loss was significantly greater in the irradiated dogs compared to the control (P less than 0.05) and the mean percentage of body weight loss correlated with the mean PABA values (P less than 0.01). In this study, the use of the BT-PABA test to evaluate progressive exocrine pancreatic function following IORT and EBRT showed an expected trend. A progressive decrease in exocrine pancreatic function in the irradiated dogs as indicated by plasma PABA levels may have been partly due to late radiation damage to acinar cells, secondary to vascular and ductular damage. At 135 days postoperatively none of the dogs showed clinical signs of exocrine pancreatic insufficiency and the plasma PABA levels were within the normal presurgical range. The progressive decrease in plasma PABA levels indicated a potential for the late development of exocrine pancreatic insufficiency. The BT-PABA test could be useful for evaluating the progressive decrease in exocrine pancreatic function and residual radiation injury to the pancreas. Because the exocrine deficiency can be managed with replacement therapy, pancreatic injury may not be a serious complication after doses of less than 30 Gy IORT with 50 Gy EBRT. Data from this study are in agreement with previous clinical and experimental reports that the duodenum is dose-limiting for IORT. Doses of 20 Gy IORT or less plus 50 Gy EBRT for treatment of carcinoma of the pancreas may not result in serious long-term complications due to radiation injury of the duodenum.

Billroth II gastrojejunostomy in dogs. Stapling technique and postoperative complications

Billroth II gastrojejunostomy was performed with surgical staplers in 6 dogs that were not irradiated and in 11 dogs that subsequently received radiation to the pancreas and proximal part of the duodenum. The dogs were monitored clinically for 135 days and then euthanatized and necropsied. Each gastrojejunostomy site was preserved in formalin and the stomal diameter was measured. No mechanical complications were encountered with the use of surgical staplers and no leakage was observed at the staple closure sites before abdominal closure. All dogs vomited approximately 100 ml of coagulated blood 4 to 8 hours after surgery, and 300 to 400 ml of brown fluid after approximately 24 hours. Vomiting was the most common clinical finding after the first 24 hours. Vomiting was subjectively graded from 1 to 3 with grade 1 representing the least severe problem and grade 3 the most severe. Grade 1 vomiting occurred in 12 of 16 dogs that survived 135 days; in the other four dogs, vomiting was classified as grade 2 or 3. All dogs with grade 1 vomiting had stomal diameters of 1.7 to 2.9 cm (mean, 2.2 +/- 0.4 cm standard deviation). Dogs with grade 2 or 3 vomiting had stomal diameters of 2.2 to 4.0 cm (mean, 3.2 +/- 0.8 cm standard deviation). The difference was statistically significant (p less than 0.005). The percentage of weight gained or lost was recorded for each dog. Two nonirradiated dogs gained body weight, whereas the other nonirradiated dogs and all irradiated dogs lost body weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Pathologic response of the pancreas and duodenum to experimental intraoperative irradiation

The pancreas and duodenum of 24 beagle dogs were given intraoperative irradiation (IORT) with 6 MeV electrons. The dose range was 17.5 Gy to 40 Gy. Billroth II gastrojejunostomy was performed on all dogs prior to irradiation. Six control dogs received only Billroth II surgery. Starting 2 weeks after surgery, dogs in the irradiation groups were given 50 Gy 6 MV X rays external beam radiation therapy (EBRT) to the pancreas and duodenum. The total dose of 50 Gy was given in 2 Gy fractions over 5 weeks. Dogs were monitored for 135 days then necropsied. Gross and histopathologic changes in the pancreas and duodenum were evaluated and quantitative analysis of pancreatic lesions done. Duodenal ulcers were found following 32.5 Gy and 40 Gy IORT. The pancreases were atrophic in irradiated dogs and exocrine pancreatic insufficiency occurred in one dog given 25 Gy. Gross pancreatic atrophy correlated with IORT dose. Histopathologic evidence of radiation damage to the pancreas was observed in acinar cells. Islet cell lesions were not apparent. There was pancreatic fibrosis and damage to blood vessels and ducts. Dose-response relationships were observed for the index of damage to the pancreas as a whole, for pancreatic fibrosis and a decrease in normal acinar cells. Although 25 Gy IORT plus 50 Gy EBRT was tolerated by the duodenum to 135 days, these doses may cause later pancreatic injury as an expression of damage to blood vessels and ducts. Exocrine pancreatic insufficiency and diabetes mellitus may thus represent potential late complications of IORT following 25 Gy or higher doses.

The diagnosis of acute acalculous cholecystitis: a comparison of sonography, scintigraphy, and CT

The clinical and laboratory diagnosis of acute acalculous cholecystitis is difficult, and the reliability of various diagnostic imaging techniques has not been established. The results of several imaging procedures performed over a 6-year period on 56 patients with clinically suspected acute acalculous cholecystitis were evaluated retrospectively. Sonography and CT were both highly sensitive (92% and 100%, respectively) and specific (96% and 100%, respectively). Hepatobiliary scintigraphy was compromised by frequent false-positives; the result was a specificity of only 38%. Percutaneous bile aspiration was insufficiently sensitive (33%) for diagnosis. Sonography was as sensitive as hepatobiliary scintigraphy and was more specific in establishing the diagnosis. Because sonography is relatively inexpensive and can be performed at the bedside, it should be regarded as a satisfactory screening procedure. However, CT is a good alternative in an easily transported patient when other intraabdominal disease is suspected.

Aorticopulmonary window in a dog

An aorticopulmonary window was diagnosed in an 18-month-old dog that had progressive exercise intolerance, hyperpnea, and cyanosis since birth. The dog was euthanatized and necropsied. Microscopic lesions in the lungs were compatible with chronic pulmonary hypertension.

Histochemical study of the anulus fibrosus in normal canine caudal cervical intervertebral discs

A qualitative assessment of glycosaminoglycans (GAGs) in the non-chondrodystrophoid canine cervical anulus fibrosus was performed using the Alcian blue/critical electrolyte concentration staining technique. Estimates of GAG concentration were deduced for two groups of dogs (average age four and eight years) by determining the hyaluronic acid, chondroitin sulphates and keratan sulphate 'alcianophilic indices'. Keratan sulphate was the predominant GAG in the four-year-old group of dogs. The concentration of keratan sulphate was equal to that of chondroitin sulphates in the eight-year-old group and the total GAG concentration was decreased. This qualitative assessment indicated that the concentrations of keratan sulphate decreased and chondroitin sulphates increased between four and eight years of age. Similar conclusions have not been reported for anuli in the thoracic and lumbar regions of the canine spine.

Portacaval shunt as treatment for hypercholesterolemia. Metabolic and morphological effects in a swine model

Since 1973 the portacaval shunt has been used as a treatment for homozygous familial hypercholesterolemia. Favorable results have been reported, but the mechanism or reduction of cholesterol is not clear. The objective of this research was to evaluate mechanisms of lipid alterations after portacaval shunting in Yucatan miniature swine. The animals were fed a high-fat diet, similar in composition to the average American diet, with or without added cholesterol. Controls were fed the atherogenic diet (+ cholesterol) for 8 months. Pigs were fed atherogenic or American diets for 8 months, then surgery (shunt or sham) was performed. They were continued on the diets for another 8 months. The vascular system was examined for the distribution and severity of atherosclerotic disease. Blood lipids and numerous biochemical indices were measured. Progression of atherosclerosis was slowed by portacaval shunting. Low density lipoprotein (LDL) concentrations were positively and high density lipoprotein (HDL) concentrations were negatively correlated with severity of atherosclerosis. Serum insulin concentrations were positively correlated with atherosclerosis. Cholesterol synthesis was increased by the shunting and decreased by cholesterol feeding. The cholesterol-fed swine is not an adequate model for familial hypercholesterolemia, but the results are consistent with inhibition of the atherosclerotic process and the involvement of lipoproteins and insulin in the mechanisms.

An audit of investigational services within general medical units

Over a period of a year data was collected on the utilisation of investigational services by three general medical units. The pattern of practice was found to be very similar between the units. The average calculated daily test cost per patient ranged from +12-23 and the average dialy number of tests per patient was less than two. The services contributing most to costs were the relatively cheap but frequently-performed laboratory and radiological investigations. The implications of these findings in relation to hospital costs and to the education of medical staff is discussed.

Evaluation of gamma radiation therapy in experimentally induced hemorrhagic pancreatitis in dogs

Acute bile-trypsin pancreatitis was induced in two groups of six dogs each. One group was given supportive treatment only; the second group was treated with irradiation of the pancreas (400 rad). A third group of six dogs was irradiated, but pancreatitis was not induced. A 13-fold increase in survival time was observed in the dogs with pancreatitis which had been irradiated. Irradiation alone was found to reduce the volume of pancreatic secretion with a relative increase in trypsin content. Modification of the inflammatory reaction by irradiation and reduction in pancreatic secretion probably account for the therapeutic effect.

Lumbar spondylectomy in the subhuman primate

Removal of the 2nd or 3rd lumbar vertebrae (or both) has been accomplished in the subhuman primate (Macaca mulatta). Variations between this animal and the dog in posture, vertebral column anatomy, and spinal cord blood supply made no apparent difference in the results when compared with those in previous experiments. All macaques were able to clinb and to use their hind legs in a normal manner within 3 days after surgical operation. Once hair had regrown over the surgical incision, persons not familiar with the animals were not able to identify the animals that had undergone surgical operation. If a single vertebra was removed, use of spinous process and a single vertebral body plate was sufficient to stabilize the vertebral column. Except for 1 rhesus macaque whose spinous process plates were removed 20 days after the operation, vertebral columns of macaques (n = 3) that underwent single spondylectomy healed in nearly normal alignment. With the removal of 2 lumbar vertebrae, the previously described stabilization procedure was not sufficient to prevent kyphotic deformity of the vertebral column. Spinous process plates from 1 macaque were removed after 64 days. However, all these macaques (n = 3) could climb and use their legs as well as others in the colony.

Inverse effect of chronically elevated blood flow on atherogenesis in miniature swine

The effect of chronically elevated blood flow on the development of atherosclerosis in miniature swine was studied. Fistulas connecting the right external iliac artery and vein were surgically created in four swine, while three were not fistulated. Pulsed Doppler velocity detection cuffs placed around the abdominal aorta and both iliac arteries of all pigs permitted chronic measurements of blood velocity, blood velocity distributions, and blood flow. All swine were fed an atherogenic diet consisting of 20% beef tallow, 3% cholesterol, and 5% cholic acid for 6 months. This diet elevated the serum cholesterol to values exceeding 500 mg/100 ml. Creation of the arteriovenous fistula (AVF) markedly elevated blood velocity and flow in the abdominal aorta and in the shunted iliac artery. In the shunted animals the aortic blood flow was 42.1 +/- 2.0 ml/sec compared with 17.3 +/- 1.4 ml/sec in the unshunted swine. The velocity distribution pattern across the vessel was also indicative of an elevated wall shear stress. After 6 months, the animals were killed and the arterial vessels examined macroscopically and microscopically for the presence of atherosclerotic lesions. In the shunted pigs, 17 +/- 15% of the lumenal surface was occupied by sudanophilic lesions, whereas 80 +/- 8% of the surface was covered by lesions in the unshunted (control) pigs. From these studies, it is apparent that mechanical factors related to blood flow rates can influence the development of atherosclerotic lesions in swine.

Thrombosis in association with atherosclerosis induced by dietary perturbations in dogs

The distribution, severity, and complications of diet-induced atherosclerosis in dogs can be altered by changing the source of fat in the diet. Thrombosis and thromboembolic disease associated with atherosclerosis occurred with diets containing beef tallow and lard of coconut oil but were absent in dogs fed cottonseed oil as a source of fat. Experiemtnal animals with and without thrombosis are of value as models in elucidating the role of platelets and thrombostatic mechanisms in atherosclerosis.

The unified concept of shock

In summary, the shock syndrome has a variety of causes although the same net physiologic insult results. The disease is a deficiency in tissue metabolism brought about by decreased capillary blood flow and cellular hypoxia. The therapeutic regimen employed in any given patient is dectated by the initial cause of shock as well as the physiologic changes that have occurred in the patient. Fluid and electrolyte therapy is the primary method of treatment. Modification of solutions and use of additional drugs may be indicated.