The role of thigh muscle and adipose tissue in knee osteoarthritis progression in women: data from the Osteoarthritis Initiative.

OBJECTIVE: To determine whether loss in thigh muscle strength in women concurrent with knee osteoarthritis progression is associated with reductions of muscle anatomical cross-sectional area (ACSA) or specific-strength (i.e., isometric force÷ACSA), and to explore relationships with local adiposity. DESIGN: Female participants from the Osteoarthritis Initiative with Kellgren-Lawrence grade ≤3, thigh isometric strength measurements, and thigh magnetic resonance images at year-two (Y2) and year-four (Y4) (n = 739, age 62 ± 9 years; body mass index measurements (BMI) 28.8 ± 5.9 kg/m2) were grouped into: (1) those with vs without symptomatic progression (≥9 increase in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)-pain [scale: 0-100]); and (2) those with vs without radiographic progression (≥0.7 mm reduction in minimum joint space width). The change in knee extensor and flexor ACSA and specific-strength, and subcutaneous and intermuscular fat (IMF) ACSAs were compared between progressors and non-progressors using analysis of covariance. RESULTS: Symptomatic progression was associated with a significantly greater loss (p < 0.001) of knee extensor ACSA (-2.0%, 95%CI -2.5, -1.5) compared to those without progression (-0.7%, 95%CI -1.0, -0.4), and greater loss (p = 0.020) of knee flexor specific-strength (-7.6%, 95%CI -11.5, -3.7; vs -2.4%, 95%CI -4.8, 0.0). Radiographic progression was associated with a significantly greater increase (p = 0.023) in IMF (+1.7%, 95%CI -0.1, +3.6) compared to those without progression (-0.6%, 95%CI -1.6, +0.3). CONCLUSION: The significant reduction in thigh muscle strength concurrent with symptomatic progression in women appears to be associated with loss of extensor muscle ACSA and flexor specific-strength. In contrast, radiographic progression appears to be unrelated to muscle properties, but to be associated with local (intermuscular) adiposity gains.

Longitudinal change in thigh muscle strength prior to and concurrent with symptomatic and radiographic knee osteoarthritis progression: data from the Osteoarthritis Initiative.

OBJECTIVE: To investigate whether symptomatic and/or radiographic knee osteoarthritis (KOA) progression is associated with prior and/or concurrent change in thigh muscle strength in men or women. DESIGN: Osteoarthritis Initiative (OAI) participants with isometric muscle strength measurements at baseline, 2- and 4-year follow-up (n = 1785: 1016 women) were grouped into 1) those with vs without symptomatic progression (i.e., increase ≥9 in WOMAC-pain [scale: 0-100]); and 2) those with vs without radiographic progression (i.e., decrease in minimum joint space width (JSW) ≥0.7 mm) between year-two and year-four follow-up. Sex-specific changes in thigh muscle strength concurrent (between year-two and year-four follow-up) and prior to (between baseline and year-two follow-up) symptomatic and radiographic progression were compared between groups (progression vs no progression) using analysis of covariance, with adjustment for age and body mass index. RESULTS: In women, but not in men, loss in knee extensor and flexor strength was greater concurrent with symptomatic progression (extensors: -3.7%, 95% confidence interval [CI] -6.4, -0.9; flexors: -7.2% 95% CI -10.7, -3.7) than in women without symptomatic progression (extensors: -0.3%, 95% CI -1.9, 1.3, P = 0.030; flexors: -2.6%, 95% CI -4.7, -0.6, P = 0.018). No association was found between extensor or flexor strength loss concurrent to radiographic progression, in either men or women, nor any statistically significant association between prior change in muscle strength with symptomatic or radiographic progression. CONCLUSION: These findings suggest that there is concurrent but not prior longitudinal association between loss in muscle strength and symptomatic KOA progression that is specific to women.

Lateral hypothalamic lesions and norepinephrine turnover in rats.

Animals with lateral hypothalamic lesions lost significantly more weight in the 18 h following this lesion than did sham-operated animals or rats with cerebral cortical lesions deprived of food for the same time period. In the acutely fasted sham-operated animals the turnover of norepinephrine in interscapular brown adipose tissue, heart, and pancreas was slowed but in fasted rats with lateral hypothalamic lesions norepinephrine turnover rates were three- to ninefold faster in all three organs. Exposure to the cold (4 degrees C) significantly increased norepinephrine turnover in the interscapular brown adipose tissue, heart, and pancreas of fasted sham-operated rats, but did not further increase the rate of turnover in lateral hypothalamic-lesioned rats. Rats with lesions in the cerebral cortex responded in a fashion similar to that of the sham-operated animals. Gastric erosions and microhemorrhagic gastric mucosa were observed in five of six acutely fasted rats with lateral hypothalamic lesions whereas all sham-operated rats had a normal appearance of the stomach lining. Animals with lateral hypothalamic lesions made 3 wk earlier also showed an increased rate of norepinephrine turnover in the interscapular brown adipose tissue, heart, and pancreas following an 18 h fast. Rats with bilateral lesions in the paraventricular region of the hypothalamus, however, responded similarly to sham-operated animals with a reduction in the turnover in norepinephrine with fasting and an increase in norepinephrine turnover rate after cold exposure even with fasting. These data suggest that lateral hypothalamic lesions produce an acute increase in turnover of norepinephrine, and that this increased turnover persists for up to 3 wk.

Pioglitazone increases insulin sensitivity, reduces blood glucose, insulin, and lipid levels, and lowers blood pressure, in obese, insulin-resistant rhesus monkeys.

The antidiabetic effects of pioglitazone hydrochloride were evaluated in 6 spontaneously obese, insulin-resistant rhesus monkeys. The animals were studied during six successive 2-wk treatment phases separated by 2-wk rest periods: two placebo phases; 0.3, 1.0, and 3.0 mg.kg-1 x day-1 pioglitazone hydrochloride phases; and a final placebo phase. During the second week of each treatment phase, serum insulin (immunoreactive insulin [IRI]), plasma glucose, and serum triglyceride (TG) levels were measured after an overnight fast and after a standardized meal. Blood pressure was measured and glucose tolerance tests (modified minimal model protocol) were performed a few days after the meal tests. Pioglitazone hydrochloride significantly improved fasting and postprandial levels of IRI, plasma glucose, and TG in a dose-related manner (P < 0.05). Fasting values during treatment with 3.0 mg.kg-1 x day-1 were reduced by 64% for IRI, 19% for plasma glucose, and 44% for TG compared with the placebo phase before treatment. Efficacy of pioglitazone hydrochloride was more marked for those animals with fasting hyperglycemia. Insulin sensitivity was increased by pioglitazone hydrochloride (P = 0.05), whereas glucose effectiveness and glucose disappearance rate were not detectably affected. Systolic and mean arterial blood pressures were significantly decreased by pioglitazone hydrochloride (P < 0.05). No toxic side effects of pioglitazone hydrochloride treatment were noted.

Complications of pregnancy and fetal development.

Although the outcome of pregnancy for women with diabetes mellitus has improved in recent years, the infant of the diabetic mother has an increased risk of major clinical problems, particularly in the early neonatal period. These include birth injury due to macrosomia, neonatal hypoglycemia, respiratory distress syndrome, and serious congenital anomalies. Because of the great difficulties encountered during attempts to investigate these problems in clinical research protocols, there is a continuing need to establish appropriate animal models of the diabetic pregnancy. Studies carried out over the past decade, primarily with chemically-induced diabetes have suggested techniques which might be useful. In general, the choice of the animal to be studied will depend on the hypotheses being addressed. For instance, small animals such as rabbits and rats made diabetic with streptozotocin have been successfully used for investigation of fetal lung development. Furthermore, the rat model has been helpful for evaluation of fetal anomalies associated with maldevelopment of the spine and central nervous system. Larger animals, such as the nonhuman primate, are more appropriate for studying placental function and amniotic fluid composition in diabetic pregnancies. The task group on pregnancy and fetal development recommends that animal models of diabetes mellitus be used for a more extensive hormonal and metabolic characterization of diabetic mothers during pregnancy, for investigation of placental physiology with respect to the transfer of substrates from mother to fetus, for systematic and comprehensive study of mechanisms controlling fetal lung development, and for delineation of the pathophysiology of neonatal hypoglycemia. It is further recommended that animal models of spontaneous diabetes such as the BB/W rat be used in future studies dealing with pregnancy and fetal development. Because females with spontaneous diabetes show reduced conception rates, there is a pressing need to enhance the fertility of these animals in order to intensify studies on fetal development.

Insights into the development of polycystic ovary syndrome (PCOS) from studies of prenatally androgenized female rhesus monkeys.

The developmental pathophysiology of polycystic ovary syndrome (PCOS) is unknown. However, prenatally androgenized female rhesus monkeys exhibit ovarian and endocrinological features that mimic those found in women with PCOS. Thus, prenatal androgen excess may provide an etiology for hyperandrogenism and anovulation in adulthood.

Effect of vagotomy on serum insulin in rats with paraventricular or ventromedial hypothalamic lesions.

The effects of vagotomy on plasma glucose and insulin levels in rats with paraventricular nuclear (PVN) or ventromedial hypothalamic (VMH) lesions were measured during a constant glucose infusion. In one experiment, vagotomy was performed 50 min after the lesions, and in a second experiment, it was performed at the same time as the lesions. After the introduction of lesions in the PVN, there was a significantly greater rise in plasma glucose than in animals with either large or small VMH lesions, both of which had plasma glucose values similar to those in the sham-lesioned animals. The rise in insulin was greater in all three lesion groups than in the sham-operated animals. Although both plasma glucose and insulin had begun to decline before the vagotomy performed 50 min after lesioning, there was a further subsequent fall after vagotomy which was greater in the VMH-lesioned animals with large lesions than in rats with PVN lesions or small VMH lesions. In the sham-lesioned rats, there was no significant change in insulin or glucose after vagotomy. When the vagotomy and hypothalamic lesions were performed simultaneously, the glucose and insulin values in all groups were the same. The present experiments suggest that VMH and PVN exert different controls over pancreatic hormone secretion. The VMH lesions appear to remove an inhibitory effect on the vagus, with resultant hyperinsulinemia in the absence of hyperglycemia. The PVN-lesioned animals show a hyperglycemia which is abolished by vagotomy, suggesting that the PVN connects to vagal fibers which activate the glucagon secretory system in the alpha-cell of the pancreas.

Obesity in male and female rhesus monkeys: fat distribution, glucoregulation, and serum androgen levels.

Obese (n = 8) and nonobese (n = 6) adult rhesus monkeys (Macaca mulatta) were assessed in terms of body size and distribution of body fat, glucose tolerance, and serum lipid, insulin, and androgen levels. The weights of the obese monkeys were more than 2 SD above the mean for their sex, while the nonobese monkeys averaged less than 0.25 SD from the mean. Obese males and females had excess body fat located predominantly in the abdominal region; abdominal circumference was highly correlated with total body fat, as estimated by the isotope dilution method (r = 0.98; P less than 0.001). Obese monkeys of both sexes had fasting hyperinsulinemia, greater insulin response to iv glucose administration, and marginally impaired glucose tolerance. Obese males had delayed maximal insulin response to glucose administration. Fasting serum triglycerides also were elevated in the obese monkeys (0.95 +/- 0.08 vs. 0.47 +/- 0.05 mmol/L; P less than 0.001). Obese males had lower serum dihydrotestosterone levels than nonobese males (3.1 +/- 0.7 vs. 5.6 +/- 0.4 nmol/L; P less than 0.01). Nonobese females had approximately 2-fold higher serum dehydroepiandrosterone sulfate levels than the other groups. We conclude that obese male and female rhesus monkeys have patterns of fat distribution and glucoregulatory abnormalities similar to those of humans with upper body obesity. The contribution of differences in androgen metabolism to the development of obesity and its complications in rhesus monkeys remain to be defined.

Timing of prenatal androgen excess determines differential impairment in insulin secretion and action in adult female rhesus monkeys.

This study determined whether timing of prenatal androgen excess resulted in differential impairment of insulin-glucose homeostasis in adult female rhesus monkeys. Ten female rhesus monkeys exposed to testosterone propionate starting on gestational day 40 (early treated), 9 females exposed to testosterone propionate starting between gestational days 100-115 (late treated), and 15 control females were studied. The modified minimal model was used to examine various measures derived from an i.v. glucose tolerance test, with regression analysis performed between these variables and body mass index. In addition, the disposition index (DI) and the hyperbolic relationship between insulin sensitivity (S(I)) and acute insulin response to glucose were examined. Early treated females demonstrated impaired pancreatic beta-cell function, as shown by diminished DI and decreased percentile ranking for the hyperbolic relationship between S(I) and acute insulin response to glucose. In contrast, late treated females exhibited both an increase in DI and a negative relationship between body mass index and S(I). These results suggest that prenatal androgen excess in female rhesus monkeys, regardless of gestational timing, perturbs insulin-glucose homeodynamics, with androgen excess in early and late gestation impairing pancreatic beta-cell function and altering insulin sensitivity, respectively.

Different central and peripheral responses to leptin in rhesus monkeys: brain transport may be limited.

The purpose of this experiment was to determine the effect of leptin administration on food intake and energy expenditure in rhesus monkeys. Four adult male rhesus monkeys, cannulated in the left lateral cerebral ventricle, were used for all phases of this experiment. Food intake was measured following intracerebroventricular injections of vehicle or three doses (500 ng, 2 micrograms, and 22 micrograms) leptin. Leptin administration resulted in a dose-dependent decrease in food intake (P < 0.05), with food intake decreased by an average of 54% at 22 micrograms leptin. Energy expenditure was also measured at two intracerebroventricular doses of leptin. Energy expenditure was not different (P > 0.10) between placebo and leptin injections at either dose. Food intake was also measured following i.v. injection of 3 mg leptin. In this case, leptin did not alter (P > 0.10) food intake, despite increasing serum leptin levels by as much as 100-fold. These results suggest that leptin is a potent inhibitor of food intake in rhesus monkeys, but this effect requires elevation of leptin concentrations in the cerebrospinal fluid or critical brain sites. The transport system for movement of leptin across the blood-brain barrier may limit the influence of circulating leptin on food intake in monkeys.

Skeletal effects of aging and menopausal status in female rhesus macaques.

To further define the nonhuman primate as a model of the adult human skeleton, we explored the impact of growth, natural menopause, and osteoarthritis on bone mass, serum markers of bone turnover (osteocalcin and C-terminal telopeptide of type I collagen) and measures of skeletal relevance (PTH, 25-hydroxyvitamin D, total alkaline phosphatase, calcium, phosphorus, creatinine, and albumin). Fifty-eight female (aged 4-30 yr) rhesus macaques were defined as growing (G; n = 12; < or = 10 yr old), adult premenopausal (APre; n = 30; > 10 yr old; eumenorrheic, high serum estradiol and low FSH), or postmenopausal (Post; n = 16; amenorrheic for at least 1 yr, with low serum estradiol and high FSH). Total body and posterior-anterior spinal bone masses were lower in G than APre animals (P < 0.05). Post females had lower total body, distal radius, and spinal bone mass than premenopausal animals (P < 0.05). Osteocalcin was higher in Post than APre animals (P < 0.01). Other measures showed no relationship with menopausal status. In older monkeys, spinal osteoarthritis became common, causing increased dual-energy x-ray absorptiometry-measured bone mass in the lumbar spinal posterior-anterior projection. In conclusion, after natural menopause, rhesus monkeys have lower bone mass and higher skeletal turnover without alteration of the calcium-vitamin D axis. As such, they are an excellent model of human estrogen-depletion bone loss.

Energy expenditure, body composition, and glucose metabolism in lean and obese rhesus monkeys treated with ephedrine and caffeine.

The administration of ephedrine and caffeine (E+C) has been proposed to promote weight loss by increasing energy expenditure and decreasing food intake. We tested this hypothesis in six lean (4-9% body fat) and six mildly to moderately obese (13-44% body fat) monkeys studied during a 7-wk control period, an 8-wk drug treatment period, and a 7-wk placebo period. During the drug treatment period, the monkeys were given ephedrine (6 mg) and caffeine (50 mg) orally three times per day. At the end of each period, a glucose tolerance test was performed, energy expenditure was measured, and body composition was determined. Treatment with E+C resulted in a decrease in body weight in the obese animals (P = 0.06). This loss in weight was primarily the result of a 19% reduction in body fat. Drug treatment also resulted in a decrease in body fat in the lean group (P = 0.05). Food intake was reduced by E+C only in the obese group (P < 0.05). Nighttime energy expenditure was increased by 21% (P < 0.03) in the obese group and 24% (P < 0.01) in the lean group with E+C treatment. Twenty-four-hour energy expenditure was higher in both groups during drug treatment. E+C did not produce systematic changes in glucoregulatory variables, whereas plasma leptin concentrations decreased in both groups with drug treatment. Overall, these results show that E+C treatment can promote weight loss through an increase in energy expenditure, or in some individuals, a combination of an increase in energy expenditure and a decrease in food intake.

Short-term calorie restriction improves disease-related markers in older male rhesus monkeys (Macaca mulatta).

Calorie restriction (CR) is widely known for its effects on life span, physiological aging and age-related disease in laboratory rats and mice. Emerging data from CR studies in rhesus monkeys suggest that this nutritional intervention paradigm may also have beneficial effects in long-lived mammals. Studies from our laboratory and others have suggested that young- or adult-onset CR might have beneficial effects on cardiovascular disease and diabetes. For example, long-term CR reduced body fat and serum triglycerides, and increased a subfraction of HDL cholesterol associated with decreased cardiovascular disease risk. These studies suggested that long-term CR begun in young or adult animals might have important effects on markers relevant to age-related disease. Few studies have examined the effects of CR initiated in older animals (rodents or monkeys), and the temporal nature of some potentially beneficial effects of CR is unknown. The present study examined several markers related to diabetes and cardiovascular disease in thirteen older adult (> 18 year) non-obese (body fat < 22%), male rhesus monkeys during a short-term CR paradigm. Specifically, we collected these data at baseline (ad libitum feeding), 10, 20, and 30% CR, and at 6 and 12 months on 30% CR. Fasting and peak insulin were significantly reduced as were the acute and second-phase insulin responses. CR also marginally reduced triglycerides (50% reduction), but had no effect on total serum cholesterol or blood pressure. Interestingly, the observed glucoregulatory changes emerged prior to any evidence of a change in body composition suggesting that certain effects of CR may not be wholly dependent on changes in body composition in older monkeys.

Skeletal effects of aging in male rhesus monkeys.

Age-related bone loss in men is receiving increased attention. In light of this, animal models for male bone loss are desirable. This study examined the effects of age and osteoarthritis (OA) on bone mineral content (BMC), bone mineral density (BMD), and markers of bone turnover and skeletal relevance in 56 male rhesus monkeys 4-34 years of age. BMC and BMD increased at all sites from 4 to 10 years of age. Male rhesus monkeys reach peak bone mass at approximately 10 years of age after which bone mass is lower at the lateral spine and distal radius. Markers of bone turnover (osteocalcin and carboxyterminal telopeptide of type I collagen [ICTP]) decreased with age. There was no relationship between PTH, 25-hydroxyvitamin D, FSH, or testosterone and age. With advancing age, the prevalence of lumbar spine OA increases dramatically, masking decreases in posteroanterior spine bone mass that are clear in the lateral projection. These data suggest that male rhesus monkeys sustain age-related bone loss in the absence of nutritional or gonadal steroid deficiencies. These animals may prove useful in studying the mechanisms of age-related bone loss.

The effect of advancing age on bone mineral content of female rhesus monkeys.

Dual-energy X-ray absorptiometry (DXA) can be used to assess bone mass in nonhuman primates; however, the changes in bone mineral across the lifespan have not been well described. The purpose of this cross-sectional study was to evaluate the effect of maturation and subsequent aging on bone mineral content (BMC) and bone size (two dimensional bone area) in female rhesus monkeys at sites analogous to those commonly evaluated in humans. Total body (n = 178) and lumbar spine (n = 167) DXA scans were performed on female rhesus monkeys aged 2.8 to 34.6 years. Radius scans (n = 86) were performed on monkeys aged 9.7 to 34.6 years. Measurement precision was comparable to that reported for humans. At all sites, BMC was highly correlated with bone area (p = 0.0001), which was positively correlated with both body weight (p < or = 0.002) and age (p < or = 0.08). Total body and lumbar spine BMC and bone area increased with maturation (p < 0.0001) until age 11 and then remained stable with further advancing age. There was little change in total body and lumbar spine area-adjusted BMC across the lifespan. At the radial sites, there were no significant changes in BMC or bone area with age, but the area-adjusted BMC and the weight- and area-adjusted BMC declined in older animals (p < 0.05). In conclusion, the female rhesus monkey does not attain peak bone mass until age 11. Significant bone loss at later ages was observed only at radial sites.

A classification of cardiac allograft rejection. A modification of the classification by Billingham.

We herein propose a classification of rejection in cardiac allografts based on the original Stanford work. Our modified classification, as a work hypothesis, defines the following grades: mild acute rejection (A-1), corresponding to Billingham's "mild rejection"; mild acute rejection with probable conversion to moderate rejection (A-2); moderate acute rejection (A-3), comparable to Billingham's "moderate rejection"; and severe acute rejection (A-4), morphologically identical with the respective grade in the Billingham classification. The resolution of rejection has been classified into two grades--early (A-5a) and late (A-5b) resolution--according to the development of granulation tissues. We also grade the degree of vasculopathy (B-1, B-2) and chronic rejection (C), which is characterized by aggressive fibrosis and persistent vasculopathy. Mild rejection with possible conversion to moderate rejection is defined by an increasing quantity of retrogressive changes in myocytes. Changes not related to transplantation are characterized in our classification by descriptive diagnosis. The proposed classification was validated by 1 year of clinical experience and by the evaluation of possible prognostic aspects of the classification.

Dietary restriction and aging in rhesus monkeys: the University of Wisconsin study.

Dietary restriction (DR) retards aging and extends the maximum lifespan of laboratory mice and rats. To determine whether DR has similar actions in a primate species, we initiated a study in 1989 to investigate the effects of a 30% DR in 30 adult male rhesus monkeys. In 1994, an additional 30 females and 16 males were added to the study. Although the animals are still middle-aged, a few differences have developed between the control and DR animals suggesting that DR may induce physiologic changes in the rhesus monkey similar to those observed in rodents. Fasting basal insulin and glucose concentrations are lower in DR compared to control animals while insulin sensitivity is higher in the restricted animals. DR has also altered circulating LDL in a manner that may inhibit atherogenesis. These results suggest that DR may be slowing some age-related physiologic changes. In addition to measures of glucose and lipid metabolism, the animals are evaluated annually for body composition, energy expenditure, physical activity, hematologic indices, and blood or urinary hormone concentrations. In the next few years, the first animals will reach the average lifespan ( approximately 26 years) of captive rhesus monkeys and it will become possible to determine if DR retards the aging process and extends the lifespan in a primate species.

Caloric restriction lowers plasma lipoprotein (a) in male but not female rhesus monkeys.

Many age-associated pathophysiological changes are retarded by caloric restriction (CR). The present study has investigated the effect of CR on plasma lipoprotein (a) [Lp(a)], an independent risk factor for the age-associated process of atherosclerosis. Rhesus monkeys were fed a control diet (n=19 males, 12 females) or subjected to CR (n=20 males, 11 females fed 30% less calories) for >2 years. All female animals were premenopausal. Plasma Lp(a) levels in control animals were almost two fold higher for males than females (47+/-9 vs 25+/-5mg/dl mean+/-SEM, p=0.05). CR resulted in a reduction in circulating Lp(a) in males to levels similar to those measured in calorie-restricted females, (27+/-5 vs 24+/-4 mg/dl mean+/-SEM). For all animals, plasma Lp(a) was correlated with total cholesterol (r=0.27, p=0.03) and LDL cholesterol (r=0.50, p=0.0001) whether unadjusted or after adjustment for treatment, gender or group. These studies introduce a new mechanism whereby CR may have a beneficial effect on risk factors for the development of atherosclerosis in primates.

Bile duct injury as a part of diagnostic criteria for liver allograft rejection.

The decisive criterium of acute liver allograft rejection was found to be the presence of the diagnostic triad of acute rejection; ie, the presence of portal inflammatory mixed infiltrates, venous endothelialitis (both portal and central), and bile duct injury. On the basis of the presence of each of the components of the diagnostic triad, criteria for the diagnosis of different degrees of acute rejection were developed, particularly focusing attention on a detailed analysis of bile duct injury. Bile duct injury was shown to be an essential part of the histopathologic changes in all grades of acute rejection in the liver allograft, the grade of severity of bile duct injury correlating to a certain extent with the grade of severity of acute rejection. Our analyses have made it evident that bile duct injury, which most probably occurs earlier in the process of acute rejection than endothelialitis, is a more sensitive parameter than endothelialitis in the diagnosis of acute rejection. Furthermore, our analyses have revealed that bile duct injury in acute rejection is likely to be an irreversible process, depending on the number of episodes of acute rejection that previously occurred. On the other hand, it has become clear from our results that bile duct injury must not be considered to be an absolute histopathologic marker of acute rejection; however, it does have to be judged synoptically in connection with the other components of the diagnostic triad and the changes that the triad cause in the hepatic parenchyma. Additional analyses of the grade of severity of cholostases have shown that the cholostases are, to a certain degree, an accompanying phenomenon of the histopathologic changes characterizing acute rejection rather than a histopathologic change that is as significant as the presence of the components of the diagnostic triad.

Bronchial circulation after experimental lung transplantation. The effect of long-term administration of prednisolone.

The effect of corticosteroids on bronchial healing after modified left lung transplantation was investigated in pigs. In groups I (n = 6) and II (n = 6), animals received cyclosporine (15 mg/kg per day) and azathioprine (2 mg/kg per day). In group II, prednisolone (1 mg/kg per day) was also administered. Bronchial blood flow was estimated at the donor carina and donor second carina with laser Doppler velocimetry and radioisotopes 7 days postoperatively; macroscopic and microscopic assessments of graft airways were performed. Bronchial blood was calculated relative to the recipient carina. In group II, bronchial blood flow at the donor carina and donor second carina was significantly higher than that of group I. Macroscopic assessment revealed more pronounced ischemic changes in group I (5 of 6 animals) than in group II (2 of 6 animals, p = not significant). Microscopically, airway samples from the donor carina revealed marked destructive changes in five of six animals in group I. In group II, only mild ischemic changes, which were limited to the respiratory epithelium, were seen. We concluded that the administration of prednisolone results in improved bronchial blood flow and decreased bronchial ischemia after lung transplantation.