Successful balloon angioplasty in a cat with unilateral left pulmonary artery branch stenosis

A 9-month-old intact male Ragdoll cat was presented for evaluation of a left-sided systolic murmur that was first auscultated during examination for a newly developed cough. Transthoracic echocardiography revealed a narrowed left pulmonary artery and an increase in flow velocities at the level of the narrowing, consistent with left pulmonary artery branch stenosis. The right pulmonary artery appeared normal. Balloon angioplasty was performed and successfully reduced pressure gradient across the stenosis. The patient continues to do well 14 months after the procedure.

Immediate outcomes of low-pressure balloon valvuloplasty for severe pulmonary valve stenosis in 20 dogs: a retrospective, single-center case series

INTRODUCTION

The primary objective of this study was to describe the immediate post-procedural outcomes in dogs with severe pulmonary stenosis that were treated with low-pressure balloon valvuloplasty (BV) at a single institution.

ANIMALS, MATERIALS AND METHODS

Retrospective case series; medical records of dogs that underwent BV performed with a balloon dilation catheter >20 mm in diameter and a burst pressure of less than 4 atm (atm) were retrospectively reviewed. Twenty animals were identified fitting the criteria. Pre-procedural and post-procedural echocardiograms and peri-procedural angiograms were reviewed. Procedural success was defined as greater than 50% reduction in echocardiographically derived transpulmonary systolic pressure gradient (TPPG) or post-procedural TPPG of less than 50 mmHg.

RESULTS

The median percent reduction from initial TPPG was 53% (range = 15-90%). Sixty percent of the dogs met the pre-specified criteria for a successful outcome. Post-procedural TPPG was not different based on valve types A or B (p=0.67), presence or absence of additional supravalvular (p=0.23) or subvalvular (p=0.83) obstructive components.

DISCUSSION

The proportion of dogs that reach the successful outcome were not different based on valve type A or B. No relationship was noted between immediate outcomes and bodyweight or pulmonary annulus diameter.

CONCLUSION

Dogs with severe pulmonic stenosis that underwent low-pressure BV had good immediate outcomes with no difference in outcome based on valve morphology. Further randomized controlled studies are needed to compare the outcomes of different strategies for BV in dogs with large-diameter pulmonary annulus.

Double-outlet right ventricle in a Vietnamese potbellied pig

A 6-month-old, neutered male, Vietnamese potbellied pig presented for evaluation of exercise intolerance and intermittent episodes of exertional cyanosis. Initial diagnostic evaluation revealed arterial hypoxemia. Transthoracic echocardiogram revealed double-outlet right ventricle (DORV) and a subaortic ventricular septal defect. Agitated saline contrast study confirmed the entry of saline contrast from the right ventricle into both pulmonary artery and aorta. Due to deterioration of clinical status, the patient was euthanized 3 months later. Gross necropsy examination was performed confirming the congenital cardiac defects noted on the echocardiogram. To the authors knowledge, this is the first case report of DORV in a Vietnamese potbellied pig.

Periprocedural vascular access complications associated with percutaneous femoral arterial access using the modified Seldinger's technique in dogs during cardiac catheterization: a single-center experience

BACKGROUND

The primary objective of this study is to evaluate the peri-procedural major and minor complications associated with percutaneous femoral arterial access using modified Seldinger's technique in dogs that underwent cardiac catheterization.

METHODS

Medical records of 62 client owned dogs that underwent percutaneous femoral arterial access for interventional cardiac procedures were retrospectively evaluated. Post-procedural manual compression was used for hemostasis. Peri-procedural vascular access complications (that occurred from procedure time to discharge) were evaluated. Vascular access complications were divided into two groups: minor complications that did not require specific therapy and major complications that did require an intervention to address the complication associated with vascular access.

RESULTS

The minor complication rate was 30.6% (19/62) with most dogs experiencing minor bruising and small hematomas. The major complication rate was 3.2% (2/62). Both major complications were associated with bleeding with one dog requiring blood transfusion and the other dog requiring fluid therapy. No peri-procedural mortality associated with vascular access was noted.

CONCLUSION

This retrospective study suggests that percutaneous femoral arterial access using the modified Seldinger's technique with post-procedural manual compression for hemostasis is viable option for vascular access during cardiac catheterization and associated with no peri-procedural mortality in dogs. The lower rate of complications noted in this study may be related to operator experiences and as such complication rate at a single center may not reflect the experience at other centers.

Infective aortic valve endocarditis in a cat with patent ductus arteriosus and perimembranous ventricular septal defect

A 3-year-old, male neutered, domestic short-haired cat presented for evaluation of respiratory distress. Transthoracic echocardiography revealed a left-to-right shunting ventricular septal defect, a left-to-right shunting patent ductus arteriosus, and a vegetative growth on the aortic valve leaflet consistent with aortic valve endocarditis. Because of poor response to therapy, the owner elected euthanasia, and a necropsy was performed. Gross necropsy examination confirmed the congenital cardiac defects, and aortic valve endocarditis was noted on the echocardiogram. Histopathological examination revealed diffuse interstitial pneumonia and evidence for systemic septic embolism including renal infarcts and brain microabscesses. To the authors' knowledge, this is the first case report of aortic valve endocarditis in a cat in association with congenital cardiac malformations.

Comparison of single- versus seven-day Holter analysis for the identification of dilated cardiomyopathy predictive criteria in apparently healthy Doberman Pinscher dogs

INTRODUCTION

The primary objective of this study was to test whether seven-day Holter recording improves the sensitivity of detecting dilated cardiomyopathy (DCM) predictive criteria (DCM_p) compared with 24-h Holter recording in asymptomatic Doberman Pinscher (DP) dogs.

ANIMALS

Twenty-eight asymptomatic DP dogs with normal echocardiographic examinations.

METHODS

Dogs with normal echocardiographic examinations underwent seven-day Holter monitoring. The presence of ≥50 ventricular premature complexes and or ≥ one couplet/one triplet/one episode of ventricular tachycardia per 24-h period was considered positive for DCM_p.

RESULTS

Five dogs were positive on the first day, and an additional six dogs tested positive from day two to seven of the Holter recording. The number of dogs positive for DCM_p detected by four days was significantly different (p = 0.031) compared with the first-day Holter recording.

CONCLUSIONS

Seven-day Holter recording detected significantly more dogs with DCM_p compared with the first-day Holter recording. Follow-up studies are warranted to evaluate the long-term accuracy of multiple-day Holter analysis in predicting the development of DCM in DP dogs.

Caprenin 1. Digestion, Absorption, and Rearrangement in Thoracic Duct-Cannulated Rats

Caprenin (CAP) is a triglyceride that primarily contains caprylic (C8:0), capric (C10:0), and behenic (C22:0) acids. This study was undertaken to determine whether or not CAP is qualitatively digested, absorbed, and rearranged like other dietary fats and oils that contain these medium-chain and very long-chain fatty acids. In vitro results showed that neat CAP, coconut oil (CO) and peanut oil (PO) were hydrolyzed by porcine pancreatic lipase. All of the neat triglycerides also were digested in vivo by both male and female rats. This was shown by the recovery of significantly more extractable lymphatic fat than with fat-free control animals and by the recovery of orally administered triglyceride-derived fatty acids in lymph triglycerides. However, substantially more PO (74%) and CO (51%) were recovered in lymph relative to CAP (10%). These quantitative differences are consistent with the fatty acid composition of each triglyceride and primary routes of fatty acid uptake. The 24-h lymphatic recovery of CAP-derived C8:0, C10:0, and C22:0 averaged 3.9%, 17.8%, and 11.2%, respectively, for male and female rats. The C8:0 and C10:0 results approximated those obtained with CO (2.0% and 16.3%, respectively). In contrast, the 24-h absorbability of C22:0 in CAP was significantly less than that seen in PO (55.4%). Finally, there was no evidence of significant rearrangement of the positions of fatty acids on glycerol during digestion and absorption. Those fatty acids recovered in lymphatic fat tended to occupy the same glyceride positions that they did in the neat administered oils. However, the lymph fats recovered from all animals dosed with fat emulsions were enriched with endogenous lymph fatty acids. It is concluded that CAP is qualitatively digested, absorbed, and processed like any dietary fat or oil that contains medium-chain and very long-chain fatty acids.

Effects of Aldose Reductase Inhibitors, Al-4114 and Al-1576, on Hepatic Biotransformation in Rabbit and Rat

Aldose reductase is part of the sorbitol pathway, which has been linked to many diabetic complications such as retinopathy and cataracts. This study has determined whether two aldose reductase inhibitors, AL-1576 and AL-4114, may be inducersof hepaticbiotransformation in New Zealandwhiterabbits or Sprague-Dawley rats. The drugs were administered either by intraperitoneal injection (ip) once a day for 4 days (10 mg/kg or 50 mg/kg) to rats and rabbits or by topical-ocular dosing three times a day for 14 days to rabbits (0.5% or 5.0%). Rats dosed ip had increased hepatic cytochrome P450 monooxygenase activity toward methoxy count ar in and benzphetamine, glutathione S-transferase activity toward 1-chloro-2,4-dinitrobenzene, and uridine diphosphate (UDP)-glucurono-syltr an sferase activity toward 4-hydroxybiphenyl and 1-naphthol. In rabbits, ip dosing increased only glucuronosyltransferase activity toward 4-hydroxybiphenyl after AL-4114, and no hepatic biotr an sformation enzyme activities were increased after topical-ocular dosing with either AL-4114 or AL-1576. Activities of other enzymes, including P-450 monooxygenase toward benzo(a)pyrene, N-acetyltr an sferase toward 2-aminofluorene and β-naphthylamine, UDP-glucuronosyltransferase toward 4-methylumbelliferone, styreneoxidehydrolase, and 2-naphthol suIfotransferase, were not increased by either topical-ocular or ip dosing with AL-1576 or AL-4114 in either rats or rabbits, although ip dosing with AL-1576 decreased monooxygenase activity toward ethoxyresorufin in rabbit liver. These results indicate that AL-1576 and AL-4114, though inducers of hepatic biotr an sformation in rats, do not induce hepatic biotran sformation in rabbits when administered by either ip or topical-ocular dosing.

Suppression of endogenous antioxidant enzymes by 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced oxidative stress in chicken liver during development

Domestic chickens (Gallus gallus) are an excellent model in which to evaluate developmental toxicity and oxidative stress because of their high sensitivity to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The goal of this study was to measure the effects of environmentally relevant doses of TCDD on endogenous hepatic antioxidant enzyme activity in hatchling chickens. The vehicle (sunflower oil) or 2, 20, or 200 pg/g TCDD was injected into chicken eggs before incubation. On hatching, livers were harvested and quickly frozen. The changes in activity of antioxidant enzymes, including glutathione peroxidase (GPx), glutathione reductase (GRx), copper zinc superoxide dismutase (SOD), and catalase (CAT) were determined as indicators of oxidative stress. TCDD exposure was associated with a significant suppression of the activities of the protective endogenous enzymes GPx, GRx, and SOD in the liver, even at the lowest dose. CAT activity was also suppressed, but not significantly. The measured decreases were 37% to 63% for GPx, 50% to 58% for GRx, 30% to 40% for SOD, and 16% to 24% for CAT. Noncomplex dose-response relationships were evident in GPx and GRx, whereas SOD and CAT curves were U-shaped. These results demonstrate that a decreased ability to scavenge reactive oxygen species may result from developmental TCDD exposure at very low doses, contributing to oxidative stress and thus to the embryotoxicity of TCDD.

Influence of treatment of diabetic rats with combinations of pycnogenol, ?-carotene, and ?-lipoic acid on parameters of oxidative stress

Treatment with antioxidants may act more effectively to alter markers of free radical damage in combinations than singly. This study has determined whether treatment with combinations of pycnogenol, beta-carotene, and alpha-lipoic acid was more effective at reducing oxidative stress in diabetic rats than treatment with these antioxidants alone. It is not feasible, based on this study, to assume that there are interactive effects that make combinations of these antioxidants more effective than any one alone to combat oxidative stress. Female Sprague-Dawley rats, normal and streptozotocin-induced diabetic, were treated (10 mg/kg/day ip for 14 days) with pycnogenol, beta-carotene, pycnogenol + beta-carotene, or pycnogenol + beta-carotene + alpha-lipoic acid; controls were untreated. Concentrations of thiobarbituric acid reactive substances, glutathione and glutathione disulfide, and activities of glutathione reductase, glutathione peroxidase, superoxide dismutase, and catalase were measured in liver, kidney, and heart. Four types of effects were observed: (1) treatment with beta-carotene alone either reversed (cardiac glutathione disulfide) or elevated (cardiac glutathione, hepatic glutathione peroxidase activity) levels seen in diabetic animals; (2) beta-carotene alone produced no effect, but pycnogenol both alone and in combinations elevated (renal glutathione peroxidase and glutathione reductase activities, hepatic glutathione reductase activity and glutathione disulfide) or depressed (cardiac glutathione disulfide) levels seen in untreated diabetic animals; (3) all treatments with antioxidants, either alone or in combination, either normalized (lipid peroxidation in all tissues), elevated (hepatic GSH, cardiac glutathione peroxidase activity), or had no effect on (activities of hepatic catalase and superoxide dismutase in all tissues) levels seen in diabetic animals; (4) in only one case (cardiac glutathione reductase activity) levels in diabetic animals treated with combinations of antioxidants were normal, but elevated in animals treated with either antioxidant alone. Antioxidant effects seem to be dependent on the nature of the antioxidant used and not on combination effects.

Effects of pycnogenol treatment on oxidative stress in streptozotocin-induced diabetic rats

Free radicals and oxidative stress have been implicated in the etiology of diabetes and its complications. This in vivo study has examined whether subacute administration of pycnogenol, a French pine bark extract containing procyanidins that have strong antioxidant potential, alters biomarkers of oxidative stress in normal and diabetic rats. Diabetes was induced in female Sprague-Dawley rats by a single injection of streptozotocin (90 mg/kg body weight, ip), resulting (after 30 days) in subnormal body weight, increased serum glucose concentrations, and an increase in liver weight, liver/body weight ratios, total and glycated hemoglobin, and serum aspartate aminotransferase activity. Normal and diabetic rats were treated with pycnogenol (10 mg/kg body weight/day, ip) for 14 days. Pycnogenol treatment significantly reduced blood glucose concentrations in diabetic rats. Biochemical markers for oxidative stress were assessed in the liver, kidney, and heart. Elevated hepatic catalase activity in diabetic rats was restored to normal levels after pycnogenol treatment. Additionally, diabetic rats treated with pycnogenol had significantly elevated levels of reduced glutathione and glutathione redox enzyme activities. The results demonstrate that pycnogenol alters intracellular antioxidant defense mechanisms in streptozotocin-induced diabetic rats.

Diabetes, oxidative stress, and antioxidants: a review

Increasing evidence in both experimental and clinical studies suggests that oxidative stress plays a major role in the pathogenesis of both types of diabetes mellitus. Free radicals are formed disproportionately in diabetes by glucose oxidation, nonenzymatic glycation of proteins, and the subsequent oxidative degradation of glycated proteins. Abnormally high levels of free radicals and the simultaneous decline of antioxidant defense mechanisms can lead to damage of cellular organelles and enzymes, increased lipid peroxidation, and development of insulin resistance. These consequences of oxidative stress can promote the development of complications of diabetes mellitus. Changes in oxidative stress biomarkers, including superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase, glutathione levels, vitamins, lipid peroxidation, nitrite concentration, nonenzymatic glycosylated proteins, and hyperglycemia in diabetes, and their consequences, are discussed in this review. In vivo studies of the effects of various conventional and alternative drugs on these biomarkers are surveyed. There is a need to continue to explore the relationship between free radicals, diabetes, and its complications, and to elucidate the mechanisms by which increased oxidative stress accelerates the development of diabetic complications, in an effort to expand treatment options.

Effects of alpha-lipoic acid on biomarkers of oxidative stress in streptozotocin-induced diabetic rats

Increased oxidative stress and impaired antioxidant defense mechanisms are important factors in the pathogenesis and progression of diabetes mellitus and other oxidant-related diseases. This study was designed to determine whether alpha-lipoic acid, which has been shown to have substantial antioxidant properties, when administered (10 mg/kg ip) once daily for 14 days to normal and diabetic female Sprague-Dawley rats would prevent diabetes-induced changes in biomarkers of oxidative stress in liver, kidney and heart. Serum glucose concentrations, aspartate aminotransferase activity, and glycated hemoglobin levels, which were increased in diabetes, were not significantly altered by alpha-lipoic acid treatment. Normal rats treated with a high dose of alpha-lipoic acid (50 mg/kg) survived but diabetic rats on similar treatment died during the course of the experiment. The activity of glutathione peroxidase was increased in livers of normal rats treated with alpha-lipoic acid, but decreased in diabetic rats after alpha-lipoic acid treatment. Hepatic catalase activity was decreased in both normal and diabetic rats after alpha-lipoic acid treatment. Concentrations of reduced glutathione and glutathione disulfide in liver were increased after alpha-lipoic acid treatment of normal rats, but were not altered in diabetics. In kidney, glutathione peroxidase activity was elevated in diabetic rats, and in both normal and diabetic animals after alpha-lipoic acid treatment. Superoxide dismutase activity in heart was decreased in diabetic rats but normalized after treatment with alpha-lipoic acid; other cardiac enzyme activities were not influenced by either diabetes or antioxidant treatment. These results suggest that after 14 days of treatment with an appropriate pharmacological dose, alpha-lipoic acid may reduce oxidative stress in STZ-induced diabetic rats, perhaps by modulating the thiol status of the cells.

Effects of quercetin on antioxidant defense in streptozotocin-induced diabetic rats

In light of evidence that some complications of diabetes mellitus may be caused or exacerbated by oxidative damage, we investigated the effects of subacute treatment with the antioxidant quercetin on tissue antioxidant defense systems in streptozotocin-induced diabetic Sprague-Dawley rats (30 days after streptozotocin induction). Quercetin, 2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-4H-1-benzopyran-4-one, was administered at a dose of 10mg/kg/day, ip for 14 days, after which liver, kidney, brain, and heart were assayed for degree of lipid peroxidation, reduced and oxidized glutathione content, and activities of the free-radical detoxifying enzymes catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase. Treatment of normal rats with quercetin increased serum AST and increased hepatic concentration of oxidized glutathione. All tissues from diabetic animals exhibited disturbances in antioxidant defense when compared with normal controls. Quercetin treatment of diabetic rats reversed only the diabetic effects on brain oxidized glutathione concentration and on hepatic glutathione peroxidase activity. By contrast, a 20% increase in hepatic lipid peroxidation, a 40% decline in hepatic glutathione concentration, an increase in renal (23%) and cardiac (40%) glutathione peroxidase activities, and a 65% increase in cardiac catalase activity reflect intensified diabetic effects after treatment with quercetin. These results call into question the ability of therapy with the antioxidant quercetin to reverse diabetic oxidative stress in an overall sense.

Effects of isoeugenol on oxidative stress pathways in normal and streptozotocin-induced diabetic rats

Because some complications of diabetes mellitus may result from oxidative damage, we investigated the effects of subacute treatment (10mg/kg/day, intraperitoneal [ip], for 14 days) with the antioxidant isoeugenol on the oxidant defense system in normal and 30-day streptozotocin-induced diabetic Sprague-Dawley rats. Liver, kidney, brain, and heart were assayed for degree of lipid peroxidation, reduced and oxidized glutathione content, and activities of the free radical-detoxifying enzymes catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase. All tissues from diabetic animals exhibited disturbances in antioxidant defense when compared with normal controls. Treatment with isoeugenol reversed diabetic effects on hepatic glutathione peroxidase activity and on oxidized glutathione concentration in brain. Treatment with the lipophilic compound isoeugenol also decreased lipid peroxidation in both liver and heart of normal animals and decreased hepatic oxidized glutathione content in both normal and diabetic rats. Some effects of isoeugenol treatment, such as decreased activity of hepatic superoxide dismutase and glutathione reductase in diabetic rats, were unrelated to the oxidative effects of diabetes. In heart of diabetic animals, isoeugenol treatment resulted in an exacerbation of already elevated activities of catalase. These results indicate that isoeugenol therapy may not reverse diabetic oxidative stress in an overall sense.

Effects of piperine on antioxidant pathways in tissues from normal and streptozotocin-induced diabetic rats

Using diabetes mellitus as a model of oxidative damage, this study investigated whether subacute treatment (10 mg/kg/day, intraperitoneally for 14 days) with the compound piperine would protect against diabetes-induced oxidative stress in 30-day streptozotocin-induced diabetic Sprague-Dawley rats. Liver, kidney, brain, and heart were assayed for degree of lipid peroxidation, reduced and oxidized glutathione (GSH and GSSG, respectively) content, and activities of the free-radical detoxifying enzymes catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase. Piperine treatment of normal rats enhanced hepatic GSSG concentration by 100% and decreased renal GSH concentration by 35% and renal glutathione reductase activity by 25% when compared to normal controls. All tissues from diabetic animals exhibited disturbances in antioxidant defense when compared with normal controls. Treatment with piperine reversed the diabetic effects on GSSG concentration in brain, on renal glutathione peroxidase and superoxide dismutase activities, and on cardiac glutathione reductase activity and lipid peroxidation. Piperine treatment did not reverse the effects of diabetes on hepatic GSH concentrations, lipid peroxidation, or glutathione peroxidase or catalase activities; on renal superoxide dismutase activity; or on cardiac glutathione peroxidase or catalase activities. These data indicate that subacute treatment with piperine for 14 days is only partially effective as an antioxidant therapy in diabetes.

Effects of coenzyme Q10 treatment on antioxidant pathways in normal and streptozotocin-induced diabetic rats

Coenzyme Q10 is an endogenous lipid soluble antioxidant. Because oxidant stress may exacerbate some complications of diabetes mellitus, this study investigated the effects of subacute treatment with exogenous coenzyme Q10 (10 mg/kg/day, i.p. for 14 days) on tissue antioxidant defenses in 30-day streptozotocin-induced diabetic Sprague-Dawley rats. Liver, kidney, brain, and heart were assayed for degree of lipid peroxidation, reduced and oxidized glutathione contents, and activities of catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase. All tissues from diabetic animals exhibited increased oxidative stress and disturbances in antioxidant defense when compared with normal controls. Treatment with the lipophilic compound coenzyme Q10 reversed diabetic effects on hepatic glutathione peroxidase activity, on renal superoxide dismutase activity, on cardiac lipid peroxidation, and on oxidized glutathione concentration in brain. However, treatment with coenzyme Q10 also exacerbated the increase in cardiac catalase activity, which was already elevated by diabetes, further decreased hepatic glutathione reductase activity, augmented the increase in hepatic lipid peroxidation, and further increased glutathione peroxidase activity in the heart and brain of diabetic animals. Subacute dosing with coenzyme Q10 ameliorated some of the diabetes-induced changes in oxidative stress. However, exacerbation of several diabetes-related effects was also observed.

Streptozotocin-induced diabetes increases gamma-glutamyltranspeptidase activity but not expression in rat liver

Earlier work describing increased biliary excretion of the acetaminophen-cysteine conjugate advanced the hypothesis that streptozotocin-induced diabetes increases gamma-glutamyltranspeptidase (GGT) expression in Sprague-Dawley rats. To test this hypothesis, rats were divided into control, diabetic, and insulin-treated diabetic groups. Diabetes was induced by intravenous injection of 45 mg streptozotocin/kg body weight and was effectively controlled by insulin treatment in the appropriate group. Densitometric quantification demonstrated that hepatic GGT activity in diabetic rats was significantly increased when compared to normal and insulin-treated diabetic controls. Histochemical staining of liver was greater in female than in male rats, and staining increased in female rat liver as the duration of diabetes lengthened from 30 to 90 days. GGT activity was increased by diabetes in liver canalicular-enriched and basolateral-enriched membrane preparations, and it was unchanged in renal brush border-enriched membranes. Total mRNA isolated from diabetic and insulin-treated diabetic rat livers did not conclusively demonstrate an elevation of GGT mRNA relative to normal. Western blot analysis showed no differences in the amount of GGT in diabetic versus normal rat livers. These data indicate that streptozotocin-induced diabetes does not alter the expression of, but does increase the activity of, GGT in liver.

Streptozotocin may provide protection against subsequent oxidative stress of endotoxin or streptozotocin in rats

Endotoxin lipopolysaccharide (LPS) and streptozotocin-induced diabetes are known to cause oxidative stress in vivo. There is some evidence that a sublethal dose of LPS provides protection against subsequent oxidative stress. Because of its wide use as a diabetogenic agent, this study was undertaken to determine if streptozotocin can likewise provide a protective effect against further oxidative stress in rats. Female Sprague-Dawley rats were given streptozotocin (50 mg/kg intraperitoneally once) prior to exposure to either bacterial endotoxin from Salmonella abortus equii (5 mg/kg intraperitoneally) or three additional daily doses of streptozotocin (50 mg/kg intraperitoneally). One week after LPS or streptozotocin treatments, oxidative stress was determined by measuring changes in antioxidant activity (glutathione peroxidase, glutathione reductase, superoxide dismutase, catalase, glutathione S-transferase, and gamma-glutamyltranspeptidase) and in concentrations of glutathione, nitrite, and thiobarbituric acid reactants in liver, kidney, intestine, and spleen. High levels of some antioxidants in the LPS-control and streptozotocin-control rats, in contrast to normal levels found in diabetes + LPS and multidose-streptozotocin rats, suggest that streptozotocin, like LPS, may confer a protective effect against subsequent oxidative stress.

Atrophic ununited diaphyseal fractures of the humerus with a bony defect

We treated 15 patients with atrophic nonunion of a diaphyseal fracture of the humerus with an associated bony defect using an autogenous cancellous bone graft and a plate to bridge the defect. There were nine men and six women with a mean age of 48 years. The mean length of the bony defect was 3 cm.

At a mean follow-up of 30 months only one fracture failed to unite. This suggests that, in the presence of a well-vascularised envelope of muscle, the application of an autogenous cancellous bone graft in conjunction with a bridging plate represents a good alternative to more demanding surgical techniques.

Atrophic ununited diaphyseal fractures of the humerus with a bony defect: treatment by wave-plate osteosynthesis

We treated 15 patients with atrophic nonunion of a diaphyseal fracture of the humerus with an associated bony defect using an autogenous cancellous bone graft and a plate to bridge the defect. There were nine men and six women with a mean age of 48 years. The mean length of the bony defect was 3 cm. At a mean follow-up of 30 months only one fracture failed to unite. This suggests that, in the presence of a well-vascularised envelope of muscle, the application of an autogenous cancellous bone graft in conjunction with a bridging plate represents a good alternative to more demanding surgical techniques.

Effects of new antioxidant compounds PNU-104067F and PNU-74389G on antioxidant defense in normal and diabetic rats

Diabetes mellitus and its complications are associated with elevated oxidative stress, leading to much interest in antioxidant compounds as possible therapeutic agents. Two new classes of antioxidant compounds, the pyrrolopyrimidines and the 21-aminosteroids, are known to inhibit lipid peroxidation and other biomolecular oxidation. We hypothesized that in the presence of excess oxidants or the impaired antioxidant defense seen in diabetes mellitus, administration of antioxidants such as these may reverse the effects of diabetes on antioxidant parameters. This study measured the effects of subchronic (14 day) treatment with a pyrrolopyrimidine (PNU-104067F) or a 21-aminosteroid (PNU-74389G) in normal and diabetic Sprague-Dawley rats. Activity levels of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase, concentrations of oxidized and reduced glutathione, and lipid peroxidation were used as measures of antioxidant defense in liver, kidney, heart, and brain tissue. In normal rats, the only effect was a 43% increase in cardiac lipid peroxidation after treatment with PNU-104067F. In diabetic rats, the only reversals of the effects of diabetes were a 30% decrease in hepatic glutathione peroxidase activity after PNU-74389G treatment and a 33% increase in cardiac glutathione disulfide concentration after PNU-104067F treatment. In contrast to these effects, increased cardiac glutathione peroxidase and catalase activities, increased brain glutathione peroxidase activity, increased hepatic lipid peroxidation, decreased hepatic glutathione content, and decreased hepatic catalase activity were seen in diabetic rats, reflecting an exacerbation of the effects of diabetes.

Decreased apoptosis as a mechanism for hepatomegaly in streptozotocin-induced diabetic rats

Insulin-dependent diabetes mellitus in both humans and animals leads to structural and functional changes including hepatomegaly. This study examined hypertrophy, hyperplasia, and apoptosis, three basic aspects of tissue growth, in livers of Sprague-Dawley and Wistar rats made diabetic by iv injection of streptozotocin 8, 30, or 90 days previously. Immunohistochemical measurement of proliferating cell nuclear antigen revealed that hepatic DNA labeling indices were similar in normal control animals and diabetic rats 30 or 90 days post diabetic induction, but were reduced to 45 to 50% of control in insulin-treated diabetic animals, perhaps due to altered receptor activity or to partial insulin resistance, as reported previously. Flow cytometry indicated a 613% increase in diploid hepatocytes in the livers of diabetic rats 30 days after the onset of diabetes, compared to control. Diabetic livers contained 29% fewer tetraploid cells, 81% fewer octaploid cells, and 20% more binucleated hepatocytes than normal controls. At 90 days, the overall smaller size of hepatocytes in diabetic tissue was evidenced by more cells per area. Insulin treatment prevented some of these changes, but did not restore ploidy to a normal distribution. Mitosis, while 300% of normal at 8 days after streptozotocin injection, was reduced to 25% of normal after 90 days of diabetes. The morphological evidence of apoptosis was decreased by 23% to 76% in the diabetic liver, and was reversed but not normalized by insulin treatment. This study indicates that the hepatomegaly observed in streptozotocin-induced experimental diabetes may be due primarily to early hyperplasia, and later decreased apoptosis.

Hepatobiliary excretion of bile acids and rose bengal in streptozotocin-induced and genetic diabetic rats

Divergent opinions regarding the effect of streptozotocin- (STZ) induced diabetes on bile flow rate may be due to the differing lengths of time after STZ administration at which bile flow was measured. Also, the biliary excretion of bile acids can influence the canalicular transport of several organic anions. Therefore, the hepatic clearance of the bile acid-dependent organic anion rose bengal was studied over a 30-day period in STZ-induced insulin-dependent Sprague-Dawley diabetic rats with elevated bile acid pools and in fatty noninsulin-dependent diabetic and lean Wistar rats. Excretion of total bile acids and rose bengal was higher in diabetic rats than in Sprague-Dawley control or lean or fatty Wistar rats. Depletion of bile acids for 10 hr in the 30-day STZ rat prevented the increased excretion of rose bengal. Bile flow rates in fatty and lean Wistar rats were similar to that in Sprague-Dawley controls. Increased bile acid excretion 7 and 14 days after STZ was not accompanied by the expected significant increase in bile flow, reflecting decreased bile acid-independent bile flow, regardless of method of calculation of bile flow (per g liver or per kg body weight). By 30 days, there were significant increases in bile acid excretion and bile flow. The increased clearance of rose bengal 7 days after STZ indicates that pathophysiological changes in the hepatocyte begin soon after the initiation of diabetes. Studies of taurocholate uptake into liver plasma membrane vesicles indicated that the maximal velocity of transport across the basolateral membrane was increased with no change in Km. This change was not observed in vesicles from insulin-treated diabetic rats. Therefore, studies employing STZ need to allow time for STZ toxicity to be overcome and for the pathology of diabetes to become established, to accurately reflect the diabetic condition.

COMPLEX NONUNION OF FRACTURES OF THE FEMORAL SHAFT TREATED BY WAVE-PLATE OSTEOSYNTHESIS

We have treated 42 consecutive complex ununited fractures of the femoral shaft by wave-plate osteosynthesis at five different medical centres. There were 13 with previous infection, 12 with segmental cortical defects, and 3 were pathological fractures. In 39 cases there had been previous internal fixation and 21 patients had had more than one earlier operation.

Union was achieved in 41 patients at an average of six months, although three had required a second bone graft. Two patients had recurrence of infection and in one this resulted in the persistence of nonunion. There were no failures of the implant. All 41 patients with union are now fully weight-bearing, but four have a leg-length discrepancy, one has axial malalignment, and nine have residual stiffness of the knee. These results are surprisingly good, despite the complexity of the initial problem, and appear to confirm the biological and mechanical advantages of the wave plate over the conventional plate for such cases.

Complex nonunion of fractures of the femoral shaft treated by wave-plate osteosynthesis

We have treated 42 consecutive complex ununited fractures of the femoral shaft by wave-plate osteosynthesis at five different medical centres. There were 13 with previous infection, 12 with segmental cortical defects, and 3 were pathological fractures. In 39 cases there had been previous internal fixation and 21 patients had had more than one earlier operation. Union was achieved in 41 patients at an average of six months, although three had required a second bone graft. Two patients had recurrence of infection and in one this resulted in the persistence of nonunion. There were no failures of the implant. All 41 patients with union are now fully weight-bearing, but four have a leg-length discrepancy, one has axial malalignment, and nine have residual stiffness of the knee. These results are surprisingly good, despite the complexity of the initial problem, and appear to confirm the biological and mechanical advantages of the wave plate over the conventional plate for such cases.

Minimal effect of acute experimental hepatitis induced by lipopolysaccharide/D-galactosamine on biotransformation in rats

When administered with D-galactosamine, lipopolysaccharide endotoxins produce a good experimental animal model of hepatitis. This galactosamine plus endotoxin model has been used widely, but the acute effect of this fixed combination of two chemicals on hepatic and extrahepatic biotransformation has not been determined. Therefore, either 2 or 4 hr after a single intraperitoneal dose of 300 mg/kg galactosamine plus 30 micrograms/kg lipopolysaccharide was administered, serum, liver, kidney, intestine, and spleen were collected. Serum enzymes (alanine and aspartate aminotransferases, sorbitol dehydrogenase, and gamma-glutamyltranspeptidase) were elevated dramatically 2 and 4 hr after treatment. Cytochrome P450 monooxygenase activity toward benzo-[a]pyrene was increased in kidney 4 hr after treatment, whereas dealkylation of 7-methoxycoumarin or 7-ethoxyresorufin was unchanged in any tissue at either time point. An increase in UDP-glucuronosyltransferase activity toward 4-methylumbelliferone and 4-hydroxybiphenyl was noted in the intestine. Conjugation of 1-chloro-2,4-dinitrobenzene with glutathione was increased in intestine and spleen 2 hr after treatment. gamma-Glutamyltranspeptidase activity was unaltered in all tissues studied. Reduced glutathione concentrations were increased significantly by different amounts depending on which organs were studied 2 or 4 hr after treatment. These results indicate that galactosamine/lipopolysaccharide-induced liver injury is not accompanied by major effects on the examined biotransformation reactions.

Hepatobiliary excretion of cysteinyl leukotrienes in three experimental models of acute hepatic injury

The acute phase response to chemically-induced organ damage involves inflammation and the production of leukotrienes. The liver ordinarily takes up, metabolizes and excretes into bile cysteinyl leukotrienes, but the effect of hepatic injury on these processes is unknown. The hepatic uptake and biliary excretion of LTC4 was studied in male Sprague-Dawley rats after exposure to either streptozotocin (45 mg/kg iv 30 days before experimentation), estradiol-17 beta-valerate (1 mg/kg sc once a week for 3 weeks) or lipopolysaccharide/D-galactosamine (33 micrograms/ kg ip; 300 mg/kg ip at 6 h and 3 h, respectively, before experimentation). Acute liver injury is produced by these treatment paradigms. Glucose concentrations and activities of several marker enzymes in plasma were measured to demonstrate hepatic injury. Biliary excretion of 3H-LTC4 was similar to normal control rats in the three types of acute liver injury. Bile flow rates after 3H-LTC4 injection were reduced in lipopolysaccharide-pretreated rats and increased in estradiol-treated animals. Total biliary excretion of leukotrienes was not altered in any disease group. Thus, these models of acute hepatic injury do not appear to influence the hepatobiliary clearance of leukotrienes.

Minimal effects of two aldose reductase inhibitors, AL-1576 and AL-4114, after subacute topical-ocular dosing on xenobiotic biotransformation in rabbits

Aldose reductase is believed to be involved in teh etiology of diabetic complications, including cataractogenesis, nephropathy, and neuropathy. AL-1576 and AL-4114, two spirohydantoin aldose reductase inhibitors, were specifically developed for prevention of diabetic cataractogenesis. This study has determined whether AL-1576 and AL-4114 are inducers of biotransformation by assaying the activities of some phase I and phase II enzymes in the liver, kidney, intestine, and five ocular tissues (cornea, lens, iris-ciliary body, retina, and choroid). The aldose reductase inhibitors were administered topically (the intended route for use in preventing cataractogenesis) in two concentrations (0.5 and 5.0%) each 3 times/day to both eyes of New Zealand white rabbits for 14 days. Lenticular aldose reductase activity was decreased by 30-75% by the aldose reductase inhibitors. Monooxygenase activity toward benzo(a)pyrene, ethoxyresorufin, and methoxycoumarin was not increased by AL-1576 or AL-4114 treatment in any tissue. Activities of 1-chloro-2,4-dinitrobenzene glutathione S-transferase, 2-naphthol sulfotransferase, and 1-naphthol UDP-glucuronosyltransferase were not significantly induced in the eight tissues. Clearly, ocular dosing with AL-4114 and AL-1576 for 14 days had little effect on hepatic, intestinal, and ocular biotransformation.

Dental surgery standards for perioperative nurses. Medical Center of Central Georgia

Practice standards for dental surgery are necessary to maintain quality care for dental patients. Specific standards or recommended practices for dental surgery have not been addressed by AORN, and none are available from the American Dental Association or the Georgia Dental Association. We incorporated the Centers for Disease Control and Prevention guidelines, and Occupational Safety and Health Administration regulations had to be incorporated into existing perioperative standards to institute dental surgery standards for our facility. The standards for dental surgery at the Medical Center of Central Georgia, Macon, evolved with the leadership of perioperative nurses.

Biotransformation in Egyptian spiny mouse Acomys cahirinus

The activities of several representative biotransformation enzymes were determined in male and female spiny mouse tissues. Cytochrome P450 monooxygenase activity toward benzo(a)pyrene was significantly greater in female spiny mouse intestine than in males. Activity toward benzphetamine in both sexes was high in the liver, with little activity in the kidney and intestine. Sulfotransferase activity was high in kidney and intestine of female spiny mice but undetectable in the same tissues in males. Hepatic glutathione S-transferase activity towards 1-chloro-2,4-dinitrobenzene in females was significantly higher than in males. UDP-Glucuronosyltransferase activity toward 1-naphthol in both sexes in the kidney was significantly higher than hepatic and intestinal activity. Intestinal N-acetyltransferase activity towards 2-aminofluorene and beta-naphthylamine was significantly greater in females than males. No consistent relation appeared to exist between biotransformation activities in spiny mouse and those in other related rodent species.

Chronic voluntary exercise may alter hepatobiliary clearance of endogenous and exogenous chemicals in rats

A chronic voluntary exercise paradigm, which mimics the exercise pattern of many humans, influences the hepatic clearance of several organic anions and a bile acid, whereas a neutral organic compound is seemingly unaffected. To extend these observations, the present work has evaluated in female Sprague-Dawley rats the effect of 6 weeks of voluntary running on the hepatobiliary elimination of endogenous bile acids and glutathione and exogenously injected rose bengal, digoxin, and acetaminophen. Inactive rats had mobility limited to their cages, whereas exercised rats had free access to a 44-in running wheel. In comparison to weight-matched sedentary rats, the exercised rats ran 4.3 +/- 0.3 miles/day, consumed 45% more food daily, had slightly greater liver/body weight ratios, and slightly elevated basal bile flow rates. Biliary excretion of endogenous bile acids was increased significantly, and excretion of reduced and oxidized glutathione was increased in exercised rats by 190% and 173% of sedentary levels, respectively. Total clearance, biliary clearance, and maximal biliary excretion of the injected organic anion rose bengal (60 mumol/kg) were elevated in exercised rats by 86%, 440%, and 85%, respectively. In contrast, there were no observed differences in pharmacokinetic parameters, serum elimination, or biliary excretion for the clinically important cardiac glycoside digoxin (dose of 100 nmol/kg). Finally, study of the analgesic acetaminophen (330 mumol/kg) revealed that total and biliary clearances were increased by 37% and 42%, respectively, in exercised rats, whereas steady-state volume of distribution and elimination half-life were not significantly different.(ABSTRACT TRUNCATED AT 250 WORDS)

Simultaneous inhibition of two tomato fruit cell wall hydrolases, pectinmethylesterase and polygalacturonase, with antisense gene constructs

The cloning and sequencing of two cDNAs representing pectinmethylesterase (PME) RNAs from tomato fruit is reported. The clones were used to construct chimeric antisense PME genes designed for high-level constitutive expression in plants. A full-length antisense PME gene construct, in conjunction with a chimeric antisense polygalacturonase gene, was introduced into tomato plants via Agrobacterium-mediated transformation. Simultaneous and significant reduction in the mRNA and protein levels of these normally highly abundant cell wall hydrolases of the pectin degradation pathway were observed in ripe fruit of transformants. Thus, antisense gene constructs in plants can be used to block multiple steps in metabolic pathways simultaneously.

Chronic physical activity: hepatic hypertrophy and increased total biotransformation enzyme activity

Does chronic voluntary physical activity alter hepatic or intestinal capacities for xenobiotic biotransformation? This question was investigated by comparing biotransformation enzyme activities in liver and small intestine of active and sedentary rats. Male rats allowed unlimited access to a running wheel and fed ad lib. for 6 weeks were weight-matched to sedentary controls; the active rats ate 22% more food than the sedentary rats (P less than 0.05). Active rats ran 2.8 +/- 0.6 miles/day. Liver weights were higher in the active rats (11.2 +/- 0.2 vs 9.8 +/- 0.2 g; P less than 0.05), as were total liver protein, and liver microsomal and cytosolic protein (P less than 0.05). As a result of liver hypertrophy, the active rats showed higher total liver activity of several biotransformation enzymes, including 2-naphthol sulfotransferase, styrene oxide hydrolase, benzphetamine N-demethylase, ethacrynic acid glutathione S-transferase and morphine UDP-glucuronosyltransferase (P less than 0.05). In contrast, there was no detectable difference in total liver N-acetyltransferase activity toward p-aminobenzoic acid, 2-naphthylamine, and 2-amino-fluorene as well as, relative hepatic enzyme activity (expressed per g liver or per mg protein) and total and relative intestinal enzyme activity. We conclude that chronic voluntary physical activity, accompanied by an increased food intake, results in liver hypertrophy and potentially increases total hepatic capacity to biotransform certain xenobiotic chemicals.

Operative treatment of bicondylar intraarticular fractures of the distal humerus

Orthopedists' lack of consensus on treatment regimens for bicondylar fractures of the distal humerus warrants further review of this uncommon fracture. We present a series of 17 bicondylar fractures of the distal humerus that had a minimum follow up of 2 years. Of these fractures, the 13 that were treated exclusively with internal fixation had 92% excellent or good results. The operative technique we describe is modified from the technique recommended by the AO group. We have found it helpful to use the radial column as the site of primary fixation with a 3.5 mm dynamic compression plate in the sagittal plane. Additional fixation is provided by a reconstruction plate placed posteriorly on the ulnar column in the coronal plane. This system of dual plates in perpendicular planes provides rigidity for early motion which, when supervised, is beneficial to a satisfactory outcome.

The Sauvé-Kapandji procedure: a salvage operation for the distal radioulnar joint

The Sauvé-Kapandji procedure, a distal radioulnar arthrodesis with surgical creation of a pseudoarthrosis in the distal ulna, was used to treat 11 patients. Although all patients had had at least one previous operation on the involved wrist, they were still having pain and functional limitations. Ten patients were available for follow-up, which averaged 33 months. Of the nine patients with posttraumatic arthritis, six had excellent results (a painless wrist that averaged 82 degrees of pronation and 83 degrees of supination). Three patients had good results (mild pain during activities with an identical range of forearm rotation). One patient who had rheumatoid arthritis had an excellent result for 3 years but recently had a radiocarpal wrist fusion because of radiocarpal arthritis. We have found the Sauvé-Kapandji procedure to be a reliable treatment option for intractable disorders of the distal radioulnar joint and recommend it as a salvage procedure when previous treatment has failed.

Comparative study of phase II biotransformation in rabbit ocular tissues

To assess the biotransformational capability of ocular tissues in the rabbit, representative phase II enzymes were assayed in five tissues from the eye, and in the liver, kidney, and intestine. Within the eye, the iris/ciliary body exhibited the highest glutathione S-transferase activity, whereas the cornea possessed the highest specific activities for N-acetyl-, sulfo-, and UDP-glucuronosyl-transferases. Cornea, iris/ciliary body, choroid, and retina exhibited significant activities of p-aminobenzoic acid N-acetyltransferase, 2-naphthol sulfotransferase, and 1-chloro-2,4-dinitrobenzene glutathione S-transferase. Despite its size and protein content, lens displayed little or no biotransformational activity. Only the iris/ciliary body conjugated sulfobromophthalein with glutathione. UDP-glucuronsyltransferase activity varied depending on tested substrates and tissues. When compared to liver, kidney, or intestine, N-acetyltransferase activity in the iris/ciliary body nearly matched the rate measured in kidney, glutathione S-transferase activity in cornea and iris/ciliary body was nearly 70 and 89%, respectively, of the rate in intestine, and corneal sulfotransferase activity was greater than that in kidney. These data suggest that biotransformation pathways are present in the eye, and particularly in ocular tissues having adequate blood supply or interfacing with the external environment.

External fixation of distal radial fractures: results and complications

External fixation of unstable fractures of the distal radius yields satisfactory results but has a high complication rate. We studied thirty-five fractures in thirty-four patients to determine whether the results obtained with external fixation warranted it use. At a mean follow-up period of 31 months, the results of treatment were assessed by interviews and clinical and radiographic examination of both wrists. Twelve fractures had an excellent result, twelve had a good result, ten had a fair result, and one had a poor result. Radiographic results were graded excellent in ten fractures, good in thirteen, fair in five, and poor in seven. No correlation was found between the anatomical results and the clinical results or the patients' subjective ratings. Complications that were related directly to the fixation pins occurred in fourteen of the fractures. There were forty-five additional complications. The frequency of complications and the limitations of external fixation demand caution on the part of the surgeon to prevent iatrogenic morbidity, which would limit the benefits of the technique.

Metacarpal and phalangeal osteotomy with miniplate fixation

We reviewed the results of corrective oseotomies performed with power tools for symptomatic malunions of metacarpal and phalangeal fractures in 10 patients. At an average follow-up of 30 months, all patients had a healed osteotomy with correct alignment and had an average increase of 30 degrees in the flexion arc of the involved digit. We recommend a surgical technique of miniplate fixation over K-wire fixation where possible; it allows precise, intraoperative correction and rigid stabilization. A shortened immobilization time and early motion are significant advantages of plate fixation. However, plates cannot be used across open growth plates or directly over areas of tendon insertion. A careful preoperative plan should always be prepared prior to any corrective osteotomy. Problems such as post-operative tendinous adhesions did not occur, nor did nonunions or delayed unions.

Open reduction and internal fixation of delayed union and nonunion of the distal humerus

Nonunion of a condylar fracture of the distal humerus rarely occurs, but when present it is difficult to manage. We recommend internal fixation of the nonunion in combination with decortication and autogenous iliac crest bone grafting along with careful selection and placement of the implant. Postoperatively, the goal is preservation of elbow motion until the nonunion heals. We reviewed the cases of five patients who had surgery for nonunion of this fracture, all of which healed within 2-3 months after surgery. At final follow-up their average arc of motion was 88 degrees.

The relation of rural alcoholism to farm economy

Several studies have suggested an association between the farm crisis of the 1980's and the increase in mental health problems in rural America. A stress hypothesis for alcoholism would indeed predict such an association. The study presented herein examines the rate of new referrals for treatment of alcohol abuse and/or dependence to state-funded agencies in Nebraska. Between mid-1978 and mid-1986, the rate of subjects seeking treatment grew steadily, paralleling an increase in both population and available treatment programs. Yet, the total number of farmers seeking treatment peaked around 1982 and declined steadily thereafter, outpacing any change in the total number of farmers in the state. Possible interpretations of these findings are discussed.

The effect of long-term streptozotocin-induced diabetes on the hepatotoxicity of bromobenzene and carbon tetrachloride and hepatic biotransformation in rats

To exclude the possibility that changes in hepatotoxicity and biotransformation were induced by diabetogen administration, the influence of long-lasting experimental insulin-dependent diabetes on the activities of benzphetamine demethylase, styrene oxide hydrolase, and UDP-glucuronosyl-transferases toward 1-naphthol, diethylstilbestrol, estrone and testosterone, and glutathione S-transferases toward 1-chloro-2,4-dinitrobenzene, ethacrynic acid, and sulfobromophthalein was studied. Adult male Sprague-Dawley rats injected with 45 mg streptozotocin/kg rapidly developed the classical symptoms of diabetes which persisted throughout the 90-day test period. Ketonemia was detectable at 6 but not at either 35 or 90 days after streptozotocin administration. After acute challenge with bromobenzene or carbon tetrachloride (CCl4), aspartate and alanine aminotransferase activities in rats diabetic for 35 and 90 days were markedly higher than those in normal rats, suggesting that diabetes potentiated the hepatotoxicity of these chemicals. Administration of 25 microliters CCl4/kg, ip, to diabetic rats decreased enzyme activities toward benzphetamine, sulfobromophthalein, 1-chloro-2,4-dinitrobenzene, and 1-naphthol. In normal rats, a dose of 400 microliters CCl4/kg, ip, was required to cause similar changes in enzyme activities. Bromobenzene (500 microliters/kg, ip) elicited opposing responses in diabetic and normal rats in N-demethylase activity, in UDP-glucuronosyltransferase activity toward 1-naphthol, estrone, and testosterone, and in glutathione S-transferase activity toward 1-chloro-2,4-dinitrobenzene. Total cytochrome P450 concentrations were reduced by both induction of diabetes and hepatotoxicant challenge. Thus, chronic uncontrolled diabetes alters the response of hepatic xenobiotic biotransformation enzymes in a non-uniform, substrate-dependent manner, independent of initial diabetogen effects. The role of cytochrome P450j in potentiating CCl4 toxicity is discussed.

Tibiofibular synostosis: an unusual cause of shin splint-like pain

Tibiofibular synostosis may be an underlying cause of tibial pain with activity or ankle pain of uncertain origin. The diagnosis may be suspected when symptoms begin and progress months after an injury, when symptoms occur with vigorous activity, and when symptoms are most pronounced during midstance and preswing phases of the gait cycle. Confirmation of the diagnosis is easily made through radiographic examination, which should include the entire leg. Bone scan may show increased tracer uptake. Interference with normal dynamic function of the fibula subjects the synostosis to repetitive stress and ultimate fatigue fracture with resultant pain. Conservative treatment is recommended initially. Surgical excision should be reserved for the athletically active patient whose symptoms are gradually progressing and disabling, and whose synostosis has taken on the appearance of mature cortical bone on radiographs. The principles of tumor biopsy should be adhered to, lest the diagnosis be in error. Finally, meticulous hemostasis and use of bone wax may lessen the possibility of recurrence.