Nanomolar quantification and identification of various nitrosothiols by high performance liquid chromatography coupled with flow reactors of metals and Griess reagent

To evaluate the histological findings in patients with chronic hepatitis C and autoimmune features, liver tissue specimens from 60 patients were graded under code for individual features and composite patterns that denoted autoimmune, viral, combined autoimmune and viral, and nondiscriminative changes. Portal, interface, and acinar hepatitis in any combination with plasma cell infiltration connoted an autoimmune pattern that was associated with higher serum levels of gamma-globulin (2.4 +/- 0.2 g/dL vs. 1.7 +/- 0.1 g/dL; P = .0003) and immunoglobulin G (2,211 +/- 227 mg/dL vs. 1,508 +/- 83 mg/dL; P = .001) than patients with other patterns. Patients with the autoimmune pattern also had a greater frequency of cirrhosis (43% vs. 8%; P = .003), higher mean Knodell score (13.2 +/- 0.9 vs. 6.8 +/- 0.9; P < .0001), and a greater occurrence of high-titer smooth muscle antibodies (SMA) (13% vs. 0%; P = .05) than patients with other histological findings. HLA DR3 also occurred more frequently in these individuals than in other patients (48% vs. 15%; P = .01) and normal subjects (43% vs. 16%; P = .01). Patients with nondiscriminative patterns and interface hepatitis had clinical findings similar to those with autoimmune patterns, except for a lower mean serum level of gamma-globulin. We conclude that the composite histological pattern that resembles autoimmune hepatitis is associated with greater immunoreactivity, inflammatory activity, and disease severity than other patterns. Interface hepatitis may be the most important histological finding associated with these clinical manifestations.     

Effects of vesnarinone, a novel orally active inotropic agent with an immunosuppressive action, on experimental cardiac transplantation in rats

BACKGROUND: Vesnarinone (VES) has been used for treatment of patients with congestive heart failure. In addition to inotropic effects, it seems to have immunosuppressive action. We tested the hypothesis that VES suppresses graft rejection, inotropic dysfunction caused by early rejection, and chronic coronary obstruction in a heterotopic rat cardiac transplantation model. METHODS: (1) To study acute rejection, hearts from Lewis-Brown Norway (LBN) rats were transplanted into Lewis rats, which were treated with or without VES (50 or 100 mg/kg/day orally). (2) In a functional study, LBN hearts with or without VES (100 mg/kg/ day) were isolated and perfused on day 3 after transplantation to assess inotropic response to isoproterenol (3 x 10(-8) M). (3) To study chronic rejection, Lewis hearts were transplanted into Fisher 344 rats, which were treated with or without VES (50 mg/kg/day) for 90 days. Coronary obstructive disease was assessed by morphometric analysis. There were five to six animals in each group. RESULTS: (1) VES (100 mg/kg/day) prolonged LBN heart survival (11.7 +/- 0.7 vs. 9.6 +/- 0.7 days in control; P < 0.05). (2) Left ventricular developed pressure was depressed in transplanted hearts regardless of VES treatment (84 +/- 12, 90 +/- 8 vs. 144 +/- 16 mmHg in untransplanted hearts; P < 0.01). The developed pressure after administration of isoproterenol in VES-treated hearts (184 +/- 20 mmHg) was higher than transplanted hearts without VES (118 +/- 16 mmHg; P < 0.05), and similar to untransplanted hearts (203 +/- 27 mmHg; P = NS). (3) Transplanted hearts treated with or without VES showed similar grades of rejection (2.0 +/- 0.3 vs. 2.6 +/- 0.2; P = NS), intimal area (6,996 +/- 3,186 vs. 13,441 +/- 5,165 microns2; NS), and coronary luminal obstruction (45 +/- 16% vs. 67 +/- 14%; NS). CONCLUSIONS: VES produces mild prolongation in survival of rat heart grafts, but has no significant effect on chronic graft atherosclerosis. VES preserves the positive inotropic effects of isoproterenol that are otherwise deteriorated by early acute rejection.     

The dipsogen angiotensin II does not stimulate ethanol intake in mice

The Banff classification of acute rejection is based on histologic grades and scores for borderline changes, glomerular, vascular, interstitial and tubular lesions. We reviewed 56 episodes of acute rejection occurring in 44 kidney allograft recipients (30 cadaveric and 14 living donor transplants), comparing Banff classification to degree of reversibility of rejection. Rejection reversal was defined as complete if serum creatinine returned < or = 25% of baseline, partial if creatinine was > 25% to < 75% of baseline, and irreversible if creatinine was > or = 75% of baseline or graft loss occurred. Eight biopsies were classified as borderline (SUM score 1.6 +/- 0.5), 14 grade I (SUM score 3.3 +/- 0.4), 19 grade II (SUM score 4.2 +/- 0.3), and 15 grade III (SUM score 8.5 +/- 0.4). SUM distinguished borderline and grade III rejections, but not grades I and II. Clinically, grade and SUM score correlated with rejection reversal. Complete reversal of rejection occurred in 93% of patients with grade I rejection, while 47% of patients with grade III had irreversible rejection. The mean SUM for complete reversal was 3.9 +/- 0.34 and was different from SUM of partial (6.0 +/- 0.86) and irreversible (8.5 +/- 0.93), P < 0.006. Meanwhile, vascular scores were similar for rejections with complete (0.9 +/- 0.2) or partial (1.0 +/- 0.4) reversal, but significantly higher in those with irreversible rejection (3.0 +/- 0.4, P < 0.000). Likewise, mean scores for tubulitis and interstitial inflammation were significantly higher for irreversible rejection. Resolution of rejection by steroids was correlated to low vascular score (steroid sensitive 0.65 +/- 0.25 vs. steroid resistant 1.42 +/- 0.18, P < 0.01), and low SUM score (steroid sensitive 3.7 +/- 0.5 vs. steroid resistant 5.22 +/- 0.43, P < 0.04). Neither scores for tubulitis nor interstitial cellular inflammation were predictive of steroid sensitivity. These data demonstrate that Banff scoring has clinical relevance in predicting rejection reversal and has implications to first-line therapy of rejection episodes.     

Reduced production of immunoreactive interleukin-1 by peripheral blood monocytes of patients with acute and chronic viral hepatitis

The in vitro production of interleukin-1 beta by peripheral blood monocytes derived from patients with various liver diseases was studied. An impaired production of immunoreactive interleukin-1 (IL-1) (mean +/- SEM) by monocytes stimulated with an optimal dose (100 ng/ml) of lipopolysaccharide was observed in patients with chronic hepatitis B (N = 13; 32 +/- 6 pg/ml) or chronic hepatitis C (N = 13; 61 +/- 12 pg/ml) as compared to those of healthy control individuals (N = 35; 166 +/- 24 pg/ml; P = 0.0003 and P = 0.015, respectively), whereas an unaltered IL-1 production was seen in patients with alcoholic cirrhosis (N = 23; 125 +/- 28 pg/ml) and primary biliary cirrhosis (N = 6; 111 +/- 33 pg/ml). Similar to the situation seen in chronic viral hepatitis, lipopolysaccharide-stimulated monocytes from patients with acute hepatitis also showed a decreased IL-1 production in the first week after onset of jaundice (N = 17; 55 +/- 20 pg/ml; P = 0.001) and a return to normal in the second and third week. An impaired production of IL-1 in chronic as well as acute viral hepatitis is a further example of the known disturbed immunoregulation in this disease.     

Fine needle aspirative biopsy of the liver in HBsAG-positive patients with end-stage renal failure

HBsAg-positive patients with end-stage renal failure have a high prevalence of asymptomatic chronic hepatitis. In order to determine the usefulness of hepatic cytology in the diagnosis of liver disease, the findings of hepatic needle core biopsy (NCB) and fine needle aspirative biopsy (FNAB) were compared in 15 HBsAg-positive uremic patients. The patients, aged 42 +/- 12 years, 14 males, were on hemodialysis for periods ranging from 13 to 105 months. The NCB was processed by standard histologic and immunohistochemical techniques and FNAB by the conventional technique, using the total corrected increment score (TCI). Plasma samples were collected for evaluation of hepatic function and for viral serologic tests. In 15 patients a diagnosis was made by NCB: normal, 7 cases; chronic persistent hepatitis, 4 cases; and chronic active hepatitis, 4 cases. When the patients were allocated into two groups according to the severity of the liver histologic findings [group I--minor changes (normal+chronic persistent hepatitis), 11 patients; group II--major changes (chronic active hepatitis), 4 patients], statistically higher values were found in the major changes group for alanine aminotransferase (49 +/- 33 vs. 24 +/- 11, p = 0.04), gamma-glutamyl transpeptidase [148 +/- 53 vs. 38 +/- 28, p < (minor) 0.02] and TCI (3.7 +/- 1.2 vs. 2.5 +/- 0.8, p = 0.04). In conclusion, liver FNAB can be useful as a screening procedure for the identification of liver histologic changes (minor or major) in uremic HBsAG-positive patients.     

T lymphocyte subsets and activation status in patients following liver transplantation

Changes in T-lymphocyte subsets have previously been shown to relate to clinical events following liver transplantation and be of prognostic significance following renal transplantation. The aim of this study was to examine T lymphocyte subsets, their activation status and the mean fluorescence intensity of cell surface markers by flow cytometric analysis, in peripheral blood of patients following liver transplantation. Stable transplant patients (n=11) had a significantly higher level of activation (HLA-DR expression ) of all T cell subsets: CD3, CD4 and CD8 compared to healthy controls: 17.5% +/- 14.0 (mean +/- SD) vs 4.7 +/- 1.8 (p=0.04), 13.7% +/- 10.3 vs 4.3 +/- 1.7 (p=0.03) and 23.8% +/- 19.9 vs 3.6 +/- 2.4 (p=0.02) respectively. A further increase in activation status occurred in all T cell subsets in association with acute cellular rejection, reaching significance for the CD4+ population: 13.7% +/- 10.2 vs 23.3% +/- 20.6 (p=0.04). The mean fluorescence intensity of the CD3+DR- and CD3+ DR+ populations were increased to 1397 +/- 869 and 1282 +/- 810 following liver transplantation compared to values of 425 +/- 204 and 376 +/- 166 respectively for controls (p<0.05). T-lymphocytes maintain a high level of activation following liver transplantation and continue to express high levels of the surface marker CD3, which may account for the occurrence of acute cellular rejection despite immunosuppression in these patients.     

The significance of citrate, uromucoid and GAG for diagnosis of renal tubular acidosis in patients with urinary calculi]

BACKGROUND: The purpose of this study was to determine the effects of early postoperative tube feeding on outcomes of liver transplant recipients. METHODS: Fifty transplant patients were randomized prospectively to receive enteral formula via nasointestinal feeding tubes (tube-feeding [TF] group) or maintenance i.v. fluid until oral diets were initiated (control group). Thirty-one patients completed the study. Resting energy expenditure, nitrogen balance, and grip strength were measured on days 2, 4, 7, and 12 after liver transplantation. Calorie and protein intakes were calculated for 12 days posttransplant. RESULTS: Tube feeding was tolerated in the TF group (n = 14). The TF patients had greater cumulative 12-day nutrient intakes (22,464 +/- 3554 kcal, 927 +/- 122 g protein) than did the control patients (15,474 +/- 5265 kcal, 637 +/- 248 g protein) (p < .002). Nitrogen balance was better in the TF group on posttransplant day 4 than in the control group (p < .03). There was a rise in the overall mean resting energy expenditure in the first two posttransplant weeks from 1487 +/- 338 to 1990 +/- 367 kcal (p = .0002). Viral infections occurred in 17.7% of control patients compared with 0% of TF patients (p = .05). Although other infections tended to occur more frequently in the control group vs the TF group (bacterial, 29.4% vs 14.3%; overall infections, 47.1% vs 21.4%), these differences were not statistically significant. Early posttransplant tube feeding did not influence hospitalization costs, hours on the ventilator, lengths of stay in the intensive care unit and hospital, rehospitalizations, or rejection during the first 21 posttransplant days. CONCLUSIONS: Early posttransplant tube feeding was tolerated and promoted improvements in some outcomes and should be considered for all liver transplant patients.     

Heart transplantation in patients over 54 years of age. Mortality, morbidity and quality of life

AIMS: As a consequence of recent advances in heart transplantation, upper age limits for the procedure have been liberalized in many centres. It was the purpose of this study to compare post-transplant mortality, morbidity and quality of life in a consecutive series of 72 patients > 54 years (mean age, 57.6 +/- 2.7 years) with a control group of 72 adult patients < or = 54 years (mean age, 42.4 +/- 9.5 years) transplanted at one centre between 1985 and 1991. METHODS AND RESULTS: Patients were followed for 41 +/- 27 months post-transplant. Actuarial 1-, 5- and 7-year survival rates were 78 +/- 5%, vs 81 +/- 5%, 52 +/- 7% vs 66 +/- 6% and 46 +/- 8% vs 63 +/- 6% in patients > 54 years and < or = 54 years, respectively (P = ns). Causes of death were not significantly different between the groups. Patients > 54 years experienced significantly fewer rejection episodes after the 6th month post-transplant (0.5 +/- 0.9 vs 0.9 +/- 1.0, P < 0.04), and incidence and treatment of rejection episodes as well as incidence of infection was comparable between the groups. Non-lymphoid malignancies, mainly skin cancer, occurred more often in the older age group (27% vs 13%, P < 0.05). Quality of life, as assessed by the Nottingham Health Profile, was better in 5/6 dimensions of social functioning in older patients and the difference reached statistical significance for the dimensions of emotional reactions (P = 0.005) and sleep (P = 0.0005). CONCLUSION: In conclusion, carefully selected patients > 54 years can undergo heart transplantation with mortality and morbidity comparable to younger patients. Quality of life post-transplant seems even to be slightly better in the older age group.     

Gene therapy for myocardial angiogenesis: initial clinical results with direct myocardial injection of phVEGF165 as sole therapy for myocardial ischemia

BACKGROUND: We initiated a phase 1 clinical study to determine the safety and bioactivity of direct myocardial gene transfer of vascular endothelial growth factor (VEGF) as sole therapy for patients with symptomatic myocardial ischemia. METHODS AND RESULTS: VEGF gene transfer (GTx) was performed in 5 patients (all male, ages 53 to 71) who had failed conventional therapy; these men had angina (determined by angiographically documented coronary artery disease). Naked plasmid DNA encoding VEGF (phVEGF165) was injected directly into the ischemic myocardium via a mini left anterior thoracotomy. Injections caused no changes in heart rate (pre-GTx=75+/-15/min versus post-GTx=80+/-16/min, P=NS), systolic BP (114+/-7 versus 118+/-7 mm Hg, P=NS), or diastolic BP (57+/-2 versus 59+/-2 mm Hg, P=NS). Ventricular arrhythmias were limited to single unifocal premature beats at the moment of injection. Serial ECGs showed no evidence of new myocardial infarction in any patient. Intraoperative blood loss was 0 to 50 cm3, and total chest tube drainage was 110 to 395 cm3. Postoperative cardiac output fell transiently but increased within 24 hours (preanesthesia=4.8+/-0.4 versus postanesthesia=4.1+/-0.3 versus 24 hours postoperative=6. 3+/-0.8, P=0.02). Time to extubation after closure was 18.4+/-1.4 minutes; average postoperative hospital stay was 3.8 days. All patients had significant reduction in angina (nitroglycerin [NTG] use=53.9+/-10.0/wk pre-GTx versus 9.8+/-6.9/wk post-GTx, P<0.03). Postoperative left ventricular ejection fraction (LVEF) was either unchanged (n=3) or improved (n=2, mean increase in LVEF=5%). Objective evidence of reduced ischemia was documented using dobutamine single photon emission computed tomography (SPECT)-sestamibi imaging in all patients. Coronary angiography showed improved Rentrop score in 5 of 5 patients. CONCLUSIONS: This initial experience with naked gene transfer as sole therapy for myocardial ischemia suggests that direct myocardial injection of naked plasmid DNA, via a minimally invasive chest wall incision, is safe and may lead to reduced symptoms and improved myocardial perfusion in selected patients with chronic myocardial ischemia.     

Methylprednisolone pharmacokinetics, cortisol response, and adverse effects in black and white renal transplant recipients

It is generally assumed that chronic glucocorticoid therapy is similar pharmacologically when administered to either black or white renal transplant recipients, resulting in adrenal suppression, low circulating plasma cortisol concentrations, and a similar degree of drug exposure and toxicity. To examine this theory and to investigate the relationship of glucocorticoid metabolism to steroid-induced adverse effects among specific ethnic groups of renal transplant recipients, 9 black and 9 white male patients chronically receiving methylprednisolone were enrolled. All patients had stable renal function and were matched for age, weight, and time since transplant. Standard pharmacokinetic parameters for methylprednisolone were determined and cortisol responses were characterized by total cortisol area under the concentration curve (AUC), return cortisol AUC, and cortisol suppression half-life. All patients received their daily oral dose of methylprednisolone (mean daily dose = 11 mg for blacks and 11 mg for whites) as an intravenous infusion with serial plasma samples obtained over 24 h. The patients were assessed for the presence of specific cushingoid manifestations (buffalo hump, moon facies) and steroid-associated diabetes. Methylprednisolone and cortisol were analyzed via HPLC. In the black patients, the mean clearance of methylprednisolone (206 +/- 70 ml/hr/kg) was significantly slower with a smaller volume of distribution (0.95 +/- 0.32 L/kg) when compared with the white group (327 +/- 129 ml/hr/kg, P = 0.03; volume of distribution = 1.33 +/- 0.27 L/kg, P = 0.015). Despite chronic methylprednisolone therapy, a definite 24-hr cortisol response pattern was noted in 15 of the 18 patients with a mean total cortisol AUC of 732 +/- 443 ng.hr/ml in blacks and 539 +/- 361 ng.hr/ml in whites (P = 0.17, black vs. white). The mean cortisol suppression half-life was 4.31 +/- 1.54 hr in black recipients and 4.11 +/- 1.49 hr in whites (P = 0.48). The mean return cortisol AUC for the black patients was 327 +/- 279 ng.hr/ml and 370 +/- 207 ng.hr/ml for white patients (P = 0.28). The serum cortisol nadir for black patients was 12.3 +/- 7.2 ng/ml, which was significantly higher than the cortisol nadir in white patients (6.4 +/- 4.4 ng/ml; P = 0.03). A majority (94%) of patients (9 black, 8 white) had moon facies and 27% of patients (3 black, 1 white) had a buffalo hump. While 5 of 9 black patients had steroid-associated diabetes, no white patients manifested this adverse effect. The black patients with diabetes had higher cortisol AUCs with lower methylprednisolone clearances than the white group.(ABSTRACT TRUNCATED AT 400 WORDS)     

Risks of subsequent pregnancies on mother and newborn in female heart transplant recipients

BACKGROUND: Female heart transplant recipients are able to carry pregnancies successfully. This study evaluates the effect of subsequent pregnancies on newborn and maternal outcomes and graft survival. METHODS: Subjects were identified through a previously reported multicenter study, case reports from literature review, and recipients entered in the National Transplantation Pregnancy Registry. A retrospective analysis was completed of 35 heart transplant recipients with first pregnancies (FP) and 12 who had one or two additional pregnancies (P>1). Newborns were assessed for gestational age, neonatal birth weight, and complications. Maternal data included pregnancy outcome, peripartum complications, including infection and rejection, current graft function, and recipient survival. RESULTS: Forty-seven pregnancies (35 FP and 12 P>1) from 35 heart transplant recipients were studied. FP outcomes included 26 live births (one set of twins), four miscarriages, and six therapeutic abortions, whereas P>1 outcomes included 11 live births (one set of twins), and two miscarriages. There was no significant difference between mean birth weights (2353+/-986 gm vs 2588+/-521 g, P>1 vs FP; mean+/-SD; p=NS) or prematurity incidence (<37 weeks; 50% vs 40%; p=NS) for the live-born infants. Compared with the FP group, there was a trend toward increased neonatal complications in P>1 (40% vs 12%; p=NS). Complications were significantly more common in premature newborns compared with full-term newborns (33% vs 5%; p < 0.05). No structural malformations were identified in the live-born infants. Maternal complication rates were the same in both groups (40%). Of 28 recipients available for follow-up, the maternal survival rate was 75% for the FP group and 89% for the P> group. Mean rejection rate per year was slightly increased after pregnancy in the P>1 group. Surviving recipients had similar graft function by echocardiographic left ventricular ejection fraction. CONCLUSIONS: Post-heart transplantation pregnancies often have successful outcomes, but there is a high incidence of prematurity and low birth weight. Subsequent pregnancies do not seem to significantly increase the incidence of complications in either the newborn or mother or increase graft rejection or failure. Larger studies of posttransplantation pregnancies may provide more definitive information.     

Differences of resected hepatocellular carcinoma with hepatitis B or C virus

BACKGROUND/AIMS: The purpose of this study was to clarify the clinicopathologic differences of hepatocellular carcinoma associated with the hepatitis B versus the hepatitis C virus. METHODOLOGY: One hundred and sixty-eight patients with resected hepatocellular carcinoma were tested for viral hepatitis. Ten (6%) had both the hepatitis B surface antigen and antibodies to the hepatitis C virus. Thirty-three (20%) had neither marker. Sixteen (9%) had only the hepatitis B surface antigen (group B), and 109 (65%) had only antibodies to the hepatitis C virus (group C). We compared groups B and C clinicopathologically. RESULTS: The mean tumor diameter was larger in group B than in group C (6.3 cm vs 3.4 cm), while group B patients were younger than group C (48 yrs vs 62 yrs, p<0.0001). Poor liver function, histologic cirrhosis and chronic active hepatitis were frequently found in group C. The 1- and 2-year tumor-free survival rates following surgery in group B were 67% and 33%, and those in group C were 73% and 49%. The 1-, 2-, and 3-year survival rates following surgery in group B were 78%, 68%, and 0%, while those in group C were 92%, 83%, and 76% (p=0.0189). CONCLUSIONS: Hepatocellular carcinoma with concomitant hepatitis B viral infection was found to present as larger tumors in younger patients with less severe liver dysfunction. Hepatocellular carcinoma with concomitant hepatitis C viral infection was often detected in follow-up studies when it was small.     

Major histocompatibility complex class II antigen expression in rejecting cardiac allografts: detection using in vivo imaging with radiolabeled monoclonal antibody

BACKGROUND: Increased expression of major histocompatibility complex class II (MHC-II) antigen occurs during cardiac allograft rejection. We tested the hypotheses that (1) radiolabeled antibody to MHC-II antigen allows detection of cardiac allograft rejection using nuclear imaging techniques and (2) uptake of radiolabeled antibody to MHC-II antigen correlates with severity of rejection. METHODS AND RESULTS: Thirteen beagles with cervical cardiac allografts were studied for 64+/-23 days by use of myocardial biopsy and in vivo imaging. Uptake of radiolabeled (131I [n=2], 123I [n=1], or 111In [n=10]) antibody to MHC-II increased over baseline in 7 animals that developed histological evidence of progressively worsening allograft rejection (group A), from 72.2+/-46.1 to 176.8+/-102.0 counts/pixel/mCi (P<.009). In 4 beagles without progressively worsening allograft rejection (group B), uptake was unchanged during follow-up (74.4+/-43.8 and 60.2+/-37.4 counts/pixel/mCi; P=NS). In animals studied with 111In-labeled antibody, uptake increased from 102.9+/-23.1 at baseline to 233.2+/-82.7 counts/pixel/mCi at follow-up in group A animals (P=.036), with no significant change in group B (91.1+/-34.9 and 75.9+/-24.9 counts/pixel/mCi; P=NS). Uptake of 111In-labeled antibody was 107.5+/-35.7, 135.9+/-70.8, and 307.8+/-90.1 counts/pixel/mCi in biopsy samples showing evidence of mild, moderate, and severe rejection, respectively (P=.001). Biopsy samples showing mild, moderate, and intense MHC-II expression antibody uptake had uptakes of 92.6+/-36.3, 158.5+/-54.7, and 307.8+/-90.1 counts/pixel/mCi, respectively (P=.00004). CONCLUSIONS: Radiolabeled monoclonal antibodies to MHC-II antigen can detect cardiac allograft rejection in this large mammal model of cardiac allograft transplantation, and this technique may have a potential role in the detection of rejection in patients after cardiac transplantation.     

Na/H exchange and H-K ATPase increase distal tubule acidification in chronic alkalosis

We examined whether H(+)-ATPase, H(+)-K(+)-ATPase, and or Na+/H+ exchange mediates increased distal tubule acidification in animals with chronic metabolic alkalosis using pharmacological inhibitors of these H+ transporters in in vivo-perfused tubules of anesthetized rats. Chronic metabolic alkalosis was induced with furosemide followed by minimum electrolyte diet and HCO3 drinking water. The reduction in net HCO3 reabsorption was greater in distal tubules of alkalotic compared to control animals perfused with Schering 28080 to inhibit H(+)-K(+)-ATPase (-6.4 +/- 0.9 vs. -1.4 +/- 0.5 pmol/mm.min-1, P < 0.02) and with EIPA to inhibit Na+/H+ exchange (-11.1 +/- 1.7 vs. -6.6 +/- 0.9 pmol/mm.min-1, P < 0.01) but was similar in distal tubules of alkalotic and control animals perfused with bafilomycin to inhibit H(+)-ATPase. The greater reduction of distal tubule net HCO3 reabsorption in alkalotic compared to control animals induced by EIPA was eliminated by systemic infusion of the endothelin receptor antagonist bosentan (-4.6 +/- 0.7 vs. -4.4 +/- 0.7 pmol/mm.min-1, P = NS) but the greater reduction induced by Schering 28080 persisted. Urine endothelin-1 (ET-1) excretion was higher in animals with maintained alkalosis (164.5 +/- 23.7 vs. 76.6 +/- 10.8 fmol/day, P < 0.03), but decreased following KCl repletion to a value (86.7 +/- 10.0 fmol/day, P < 0.02 vs. respective before-KCl value) that was not different from that for KCl-repleted control animals (79.9 +/- 8.7 fmol/day, P = NS vs. KCl-repleted alkalotic animals). The data support that augmented distal tubule acidification in alkalotic animals is due to increased H(+)-K(+)-ATPase and Na+/H+ exchange activity, the latter stimulated by endogenous endothelins.     

Coronary compliance in patients following orthotopic heart transplantation. An intravascular ultrasound study

BACKGROUND: The aim of this study was to investigate coronary compliance in patients early and 71.8 weeks after orthotopic heart transplantation. METHODS: Thirty patients (mean age 51.4 years, women n = 6) underwent coronary angiography early after orthotopic heart transplantation (mean interval 11.6 +/- 5.5 weeks), by which time 12 recipients had already been treated for episodes of rejection. A total of 153 different coronary segments were investigated using a mechanical 30 MHz intravascular ultrasound system. In all segments, the intimal index and the circumferential extension of the vessel wall, which had a three-layered appearance, were assessed. Systolic-diastolic changes in area, and pressure with respect to vessel wall area, were used to study normalized compliance. All measurements were repeated in a subgroup of 13 patients 71.8 +/- 10.7 weeks after transplantation. RESULTS: At the first investigation, the mean intimal index of all estimated cross-sectional areas was 0.07 +/- 0.10. The mean circumferential extension of the 'three-layered' coronary vessel wall was 74 degrees +/- 101 degrees. No correlation could be found between normalized compliance and the intimal index (r = -0.322, P < 0.001) or between normalized compliance and the circumferential extension of the three-layered vessel wall (r = -0.362, P < 0.001). Donor age did not correlate with normalized compliance either (r = -0.515, P = 0.004). In 12 patients with proven rejection periods before the first investigation, normalized compliance was significantly lower (1.76 +/- 0.81 mmHg-1) than in those without rejection (2.95 +/- 1.22 mmHg-1, P = 0.005). Both the intimal index and the circumferential extension of the three-layered architecture of the vessel wall were significantly higher in recipients with rejection periods. A comparison of the subgroup of 13 recipients between first and second investigation showed that the intimal index increased slightly from 0.03 +/- 0.03 to 0.09 +/- 0.13 (ns) 71.8 weeks after transplantation, but that normalized compliance did not differ significantly between the first and the follow-up investigation. CONCLUSIONS: Early after orthotopic heart transplantation, normalized compliance does not correlate with donor age or the extent of atherosclerotic vessel alterations identifiable by intravascular ultrasound. Early rejection periods are associated with reduced coronary arterial compliance. Using intravascular ultrasound, this adverse functional effect on arterial compliance can be observed together with an increase in the intimal index.     

Forearm nitric oxide balance, vascular relaxation, and glucose metabolism in NIDDM patients

Endothelium-dependent and -independent vascular responses were assessed in 10 NIDDM patients and 6 normal subjects with no evidence of atherosclerotic disease. Changes in forearm blood flow and arteriovenous (AV) serum nitrite/nitrate (NO2-/NO3-) concentrations were measured in response to intra-arterial infusion of acetylcholine (ACh) (7.5, 15, 30 microg/min, endothelium-dependent response) and sodium nitroprusside (SNP) (0.3, 3, 10 microg/min, endothelium-independent response). Insulin sensitivity (determined by minimal model intravenous glucose tolerance test) was lower in NIDDM patients (0.82 +/- 0.20 vs. 2.97 +/- 0.29 10(4) min x microU(-1) x ml(-1); P < 0.01). Baseline forearm blood flow (4.8 +/- 0.3 vs. 4.4 +/- 0.3 ml x 100 ml(-1) tissue x min(-1); NS), mean blood pressure (100 +/- 4 vs. 92 +/- 4 mmHg; NS), and vascular resistance (21 +/- 1 vs. 21 +/- 1 units; NS), as well as their increments during ACh and SNP, infusion were similar in both groups. No difference existed in baseline NO2-/NO3- concentrations (4.09 +/- 0.33 [NIDDM patients] vs. 5.00 +/- 0.48 micromol/l [control subjects]; NS), their forearm net balance (0.31 +/- 0.08 [NIDDM patients] vs. 0.26 +/- 0.08 micromol/l x 100 ml(-1) tissue x min(-1); NS), and baseline forearm glucose uptake. During ACh infusion, both NO2- and NO3- concentrations and net balance significantly increased in both groups, whereas glucose uptake increased only in control subjects. When data from NIDDM and control groups were pooled together, a correlation was found between the forearm AV NO2- and NO3- differences and blood flow (r = 0.494, P = 0.024). On the contrary, no correlation was evident between NO2- and NO3- concentrations or net balance and insulin sensitivity. In summary, 1) no difference existed in basal and ACh-stimulated NO generation and endothelium-dependent relaxation between uncomplicated NIDDM patients and control subjects; 2) in both NIDDM and control groups, forearm NO2- and NO3- net balance following ACh stimulation was related to changes in the forearm blood flow; and 3) ACh-induced increase in forearm blood flow was associated with an increase in glucose uptake only in control subjects but not in NIDDM patients. In conclusion, our results argue against a role of impaired NO generation and blood flow regulation in determining the insulin resistance of uncomplicated NIDDM patients; rather, it supports an independent insulin regulation of hemodynamic and metabolic effects.     

Structural and functional alterations of the intramyocardial coronary arterioles in patients with arterial hypertension

BACKGROUND: In hypertensive patients with angina pectoris, the coronary vasodilator reserve is frequently impaired despite a normal coronary angiogram. Experimental data indicate that structural alterations of the intramyocardial coronary vasculature contribute to an increased minimal coronary resistance and a diminished coronary flow reserve. METHODS AND RESULTS: In 14 patients (10 men and 4 women) with arterial hypertension and 8 normotensive subjects, minimal coronary resistance and vasodilator reserve (dipyridamole: 0.5 mg/kg body wt, gas chromatographic argon method) were determined after the angiographic exclusion of relevant coronary artery disease. Coronary reserve was depressed in hypertensive patients (2.7 +/- 2.3 vs 4.6 +/- 1.3, P < or = .05) due to increased minimal coronary resistance (0.64 +/- 30 vs 0.24 +/- 0.055 mm Hg.min.100 g.mL-1, p < or = 0.002). In right septal biopsies, mean external arteriolar diameter (21.6 +/- 2.3 vs 17.2 +/- 2.5 microns, P < or = .001), mean arteriolar wall area (271 +/- 61 vs 172 +/- 62 microns 2, P < or = .01), percent medial wall area (69.9 +/- 4.0 vs 66.0 +/- 3.2%W, P < or = .05), mean periarteriolar fibrosis area (216 +/- 122 vs 104 +/- 68 microns 2, P < or = .05), and volume density of total interstitial fibrosis (3.6 +/- 1.8 vs 1.9 +/- 0.5Vv% fibrosis, P < or = .05) were increased in hypertensive patients compared with normotensive subjects. Minimal coronary resistance correlated with %W (r = .6, P < or = .003) and Vv% fibrosis (r = .62, P < or = .002). Left ventricular mass index (111 +/- 21 vs 97 +/- 17 g/m2, P = NS) and left ventricular end-diastolic pressure (12 +/- 6 vs 8 +/- 3 mm Hg, P = NS) did not correlate significantly with minimal coronary resistance. In multivariate analysis, both %W and Vv% fibrosis explained half of the variability of minimal coronary resistance (r2 = .5, P < or = .002). CONCLUSIONS: Structural remodeling of the intramyocardial coronary arterioles and the accumulation of fibrillar collagen are decisive factors for a reduced coronary dilatory capacity in patients with arterial hypertension and angina pectoris in the absence of relevant coronary artery stenoses.