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.