The concept of "whole perforator system" in the lateral thoracic region for latissimus dorsi muscle-preserving large flaps: An anatomical study and case series

Background

Previous studies have reported on the abundant cutaneous perforating blood vessels around the latissimus dorsi (LD) lateral border, such as a thoracodorsal artery perforator (TDAP) of septocutaneous type (TDAP-sc) and muscle-perforating type (TDAP-mp), or the lateral thoracic artery perforator (LTAP). These perforators have been clinically utilized for flap elevation; however, there have been few studies that accurately examined all the cutaneous perforators (TDAP-sc, TDAP-mp, LTAP) around the LD lateral border. Here, we propose a new “whole perforator system” (WPS) concept in the lateral thoracic region and a methodology that enables elevating large flaps with reliable perfusion in a muscle-preserving manner.

Methods

We first performed an anatomical study that verified the number and perforating points of all perforators around the LD lateral border using the results of dynamic contrast-enhanced magnetic resonance imaging of patients with breast cancer. Following the anatomical evaluation, we performed large muscle-preserving flap transfer that contained all of the perforators around the LD lateral border in an actual clinical setting.

Results

A total of 175 latissimus dorsi from 98 patients were included. The mean number of perforators (TDAP-sc + TDAP-mp + LTAP) per side was 4.51±1.44 (2–9); TDAP-sc was present in 57.1% (100/175) of cases, and TDAP-mp in 76.6% (134/175); the TDAP total prevalence rate (TDAP-sc + TDAP-mp) was 96.0% (168/175). The LTAP existence rate was 94.3% (165/175). Distance from the axillary artery to the TDAP-sc was 148.7±56.3 mm, which was significantly proximal to the TDAP-mp (183.8±54.2 mm) and LTAP (172.2±81.3 mm).

Conclusion

The lateral thoracic region has an abundant cutaneous perforator system derived from the descending branch of the thoracodorsal and lateral thoracic arteries. Clinical application of the lateral thoracic WPS flap is promising, with a large survival area even with muscle-preserving procedures and requiring a relatively simple procedure.

Chronological flap volume and distribution changes after reconstruction of total maxillectomy defect using a rectus abdominis myocutaneous flap

BACKGROUND/PURPOSE

After total or subtotal maxillectomy, reconstruction using a free rectus abdominis myocutaneous (RAMC) flap is a fundamental and useful option. The purpose of the present study was to clarify the degree of flap volume change and volume distribution change with time after total or subtotal maxillectomy and free RAMC flap reconstruction and to examine the factors affecting the results.

METHODS

A total of 20 patients who underwent total or subtotal maxillectomy with free RAMC flap reconstruction were examined, and the flap volume change rate (volume at final evaluation [POD 181-360] / volume at initial evaluation [POD 5-30]) was investigated using the results of imaging tests. Moreover, the flap was divided into four blocks (A-D) in the cranio-caudal direction, and the volume change of each block was individually analyzed.

RESULTS

The overall volume change rate of fat/muscle/total was 0.84 ± 0.21/0.36 ± 0.08/0.67 ± 0.15, at the mean follow-up period of 309±35 days after the operation. The multiple regression analysis revealed that weight loss (for fat), postoperative RT (for fat and muscle), and young age (for muscle) were independently associated with flap volume loss. The results also indicated that the fat volume was stable, whereas the muscle volume decreased to <40% over time, assuming there were no influencing factors. Regarding flap volume distribution change, the fat volume tended to gather toward the central-cranial direction, while the muscle volume gathered toward the cranial direction, and total flap volume gathered toward the central direction.

Soft silicone foam dressing is more effective than polyurethane film dressing for preventing intraoperatively acquired pressure ulcers in spinal surgery patients: the Border Operating room Spinal Surgery (BOSS) trial in Japan

Preventing intraoperatively acquired pressure ulcers (IAPUs) in patients undergoing spinal surgery in the prone position using a Relton-Hall frame is challenging. We investigated the efficacy of soft silicone foam dressings in preventing IAPUs. A prospective dual-center sham study was conducted among patients undergoing elective spinal surgery in a general hospital and a university hospital in Japan. The incidence of IAPUs that developed when soft silicone foam dressings and polyurethane film dressings were used was compared on two sides in the same patient. IAPUs developed on the chest in 11 of 100 patients (11%). Polyurethane film dressings were associated with a significantly higher rate of IAPUs than soft silicone foam dressings (11 versus 3, P = 0·027). A multivariate logistic regression analysis revealed that a diastolic blood pressure of <50 mmHg (P = 0·025, OR 3·74, 95% confidence interval [CI] 1·18-13·08) and the length of surgery (by 1 hour: P = 0·038, OR 1·61, 95% CI 1·03-2·64) were independently associated with the development of IAPUs. The use of soft silicone foam dressings reduced the risk of IAPUs (P = 0·019, OR 0·23, 95% CI 0·05-0·79) and was more effective than film dressings for preventing IAPUs in spinal surgery patients.

Effects of SSM (specific substance maruyama) on HBe antigen-positive chronic hepatitis B -clinical efficacy and modulation of cytokines

Twenty-three patients with HBe antigen-positive chronic hepatitis B were treated with capitalite first letters Maruyama (SSM). HBe antigen turned negative in 15 patients. The levels of various cytokines in pre- and post-treatment frozen serum samples from six patients whose HBe antigen turned negative and from five whose HBe antigen did not were examined. Reduction of serum interleukin (IL) -10 level to below 20 pg/ml was observed after SSM treatment in four of the six patients whose HBe antigen turned negative. SSM was found to stimulate the production of interferon (IFN) -gamma in peripheral blood cells from two healthy volunteers. This stimulatory effect was confirmed in 12 out of 24 healthy volunteers. SSM augmented the production of IFN-gamma in eight out of 10 patients with chronic hepatitis B and nine of 10 with hepatitis C. These results demonstrate for the first time that SSM stimulates the production of IFN-gamma in human peripheral blood cells and also suggest that treatment of HBe antigen-positive chronic hepatitis B patients with SSM leads to the clearance of HBe antigen and normalization of serum aspartate aminotransferase levels through inhibition of IL-10 and stimulation of IFN-gamma.

Synthesis and antiviral activity of novel anti-VZV 5-substituted uracil nucleosides with a cyclopropane sugar moiety

A series of 5-substituted uracil nucleoside derivatives with a 1(1'S, 2'R)-[1',2'-bis(hydroxymethyl)cyclopropyl]methyl group as an acyclosugar moiety were synthesized and evaluated for their anti-herpetic activities. Among the compounds synthesized, (E)-5-halovinyluracil derivatives showed superior anti-varicella zoster virus (VZV) activity over acyclovir (ACV) but were less potent than ACV against herpes symplex virus type-1 (HSV-1). IC(50) values for the VZV Kawaguchi strain were 0.027 for Br, 0.070 for Cl, and 0.054 microg/mL for I derivatives and 3.4 microg/mL for ACV. The most potent compound, (1'S,2'R)-5-[(E)-2-bromoethenyl]-1-[[1', 2'-bis(hydroxymethyl)cycloprop-1'-yl]methyl]-2,4-(1H, 3H)-pyrimidinedione (3a), was 40-60-fold more potent than ACV against clinical isolates of VZV. It showed good oral bioavailability in rats (68.5%) and, unlike (E)-5-(2-bromovinyl)-1-beta-D-arabinofuranosyluracil (BVaraU), did not result in the release of (E)-5-(2-bromovinyl)uracil (BVU), a potent dihydropyrimidine dehydrogenase inhibitor, in plasma after oral administration.

Evaluation of anti-herpesvirus activity of (1'S,2'R)-9-[[1',2'-bis(hydroxymethyl)cycloprop-1'-yl]methyl]- guanine (A-5021) in mice

The anti-herpesvirus activity of (1'S,2'R)-9-[[1',2'-bis(hydroxymethyl)cycloprop-1'-yl]methyl]guani ne (A-5021) was evaluated in murine cells and in several murine models of herpes simplex virus (HSV) infection. Against HSV type 1 (HSV-1), A-5021 was 15-30- and 30-60-fold more active, and against HSV type 2 (HSV-2), it was 2- and 8-fold more active than acyclovir and penciclovir in Balb/3T3 cells, respectively. When antiviral compounds were administered orally (once daily) to mice infected intraperitoneally with HSV-1 (Tomioka), A-5021 was more active than acyclovir or famciclovir in spite of its relatively low oral bioavailability. A-5021 was as active as penciclovir when the antiviral compounds were given intravenously (three times daily) to mice infected intraperitoneally with HSV-2 (186). In mice with a cutaneous HSV-1 (KOS) infection, three times daily oral therapy with A-5021 at 25 mg/kg per day produced more significant reduction in severity of skin lesions than equivalent treatment with acyclovir or famciclovir. In mice infected intracerebrally with HSV-1 (Tomioka), complete survival was observed in the group treated intravenously with A-5021 at 25 mg/kg per day (three times daily), while more than 50% of mice died in the groups treated intravenously with acyclovir of up to 100 mg/kg per day (three times daily). Moreover, A-5021 was more effective than acyclovir in clearing infectious virus from the brain. These findings demonstrate that A-5021 has potent anti-HSV activity in several murine models.

Mode of action of (1'S,2'R)-9-[[1',2'-bis(hydroxymethyl) cycloprop-1'-yl]methyl]guanine (A-5021) against herpes simplex virus type 1 and type 2 and varicella-zoster virus

The mode of action of (1'S,2'R)-9-([1', 2'-bis(hydroxymethyl)cycloprop-1'-yl]methyl)guanine (A-5021) against herpes simplex virus type 1 (HSV-1), HSV-2, and varicella-zoster virus (VZV) was studied. A-5021 was monophosphorylated at the 2' site by viral thymidine kinases (TKs). The 50% inhibitory values for thymidine phosphorylation of A-5021 by HSV-1 TK and HSV-2 TK were comparable to those for penciclovir (PCV) and lower than those for acyclovir (ACV). Of these three agents, A-5021 inhibited VZV TK most efficiently. A-5021 was phosphorylated to a mono-, di-, and triphosphate in MRC-5 cells infected with HSV-1, HSV-2, and VZV. A-5021 triphosphate accumulated more than ACV triphosphate but less than PCV triphosphate in MRC-5 cells infected with HSV-1 or VZV, whereas HSV-2-infected MRC-5 cells had comparable levels of A-5021 and ACV triphosphates. The intracellular half-life of A-5021 triphosphate was considerably longer than that of ACV triphosphate and shorter than that of PCV triphosphate. A-5021 triphosphate competitively inhibited HSV DNA polymerases with respect to dGTP. Inhibition was strongest with ACV triphosphate, followed by A-5021 triphosphate and then (R,S)-PCV triphosphate. A DNA chain elongation experiment revealed that A-5021 triphosphate was incorporated into DNA instead of dGTP and terminated elongation, although limited chain extension was observed. Thus, the strong antiviral activity of A-5021 appears to depend on a more rapid and stable accumulation of its triphosphate in infected cells than that of ACV and on stronger inhibition of viral DNA polymerase by its triphosphate than that of PCV.

Synthesis and antiviral activity of novel acyclic nucleosides: discovery of a cyclopropyl nucleoside with potent inhibitory activity against herpesviruses

A series of acyclic nucleosides with two hydroxymethyl groups mimicking the 3'- and 5'-hydroxyl groups of the 2'-deoxyribose moiety were prepared and evaluated for their antiherpetic activity. Among those, 9-[[cis-1', 2'-bis(hydroxymethyl)cycloprop-1'-yl]methyl]guanine (3) showed extremely potent antiviral activity against herpes simplex virus type-1 (HSV-1) with good selectivity. Both enantiomers of 3 were synthesized starting from chiral epichlorohydrins, and only one of the enantiomers with 1'S,2'R-configuration (3a) exhibited strong antiherpetic activity (IC50 of 0.020 microg/mL against HSV-1 Tomioka vs 0.81 microg/mL for acyclovir). Enantiomer 3a was also more inhibitory than acyclovir against varicella-zoster virus (VZV) but ineffective against human immunodeficiency virus (HIV). Compound 3a is phosphorylated by HSV-1 thymidine kinase (TK) very efficiently. The relationship between conformation and antiherpetic activity in this series of compounds is discussed.

Effects of the alpha-/beta-blocking agent carvedilol on hepatic and systemic hemodynamics in patients with cirrhosis and portal hypertension

To enhance the portal hypotensive effect of nonselective beta-blockers, combinations of vasoactive agents with different mechanisms should be considered. The effect of carvedilol (CAS 72956-09-3, Artist), and alpha-/beta-blocking agent, on hepatic and systemic hemodynamics in 10 patients with portal hypertension was evaluated. After administration of carvedilol, the hepatic venous pressure gradient (HVPG) decreased from 15.9 +/- 3.2 mmHg to 13.3 +/- 4.0 mmHg (mean +/- SD) at 60 min (-15%) and to 12.9 +/- 3.0 mmHg at 90 min (-17%, p < 0.05). However, only 5 patients showed a decrease of HVPG by more than 20% at 60 or 90 min. The estimated hepatic blood flow (EHBF) was not significantly reduced. In contrast, heart rate (-8%, p < 0.05), mean arterial pressure (-10%, p < 0.01), and cardiac index (CI) (-8%, p < 0.05) were all reduced at 90 min, while total systemic vascular resistance was not altered. The reduction of HVPG was significantly correlated with the decrease of CI (r = 0.6415, p < 0.05). The portal hypotensive effect of carvedilol may mainly result from a reduction of CI. However, because of the greater reduction of HVPG than that of CI, other additive actions were suggested.

N-alkylated 1,4-dihydropyridines: new agents to overcome multidrug resistance

New N-alkylated 1,4-dihydropyridine derivatives were synthesized and their ability to overcome multidrug resistance was examined in vincristine-resistant P388 cells (P388/VCR cells). Compounds that possessed an arylalkyl substituent on the dihydropyridine ring nitrogen were more potent than verapamil in potentiating the cytotoxicity of vincristine against P388/VCR cells. However, neither drug effectively enhanced the antitumor activity of vincristine in tumor-bearing mice. Introduction of basic nitrogen-containing substituents on the side chain of 1,4-dihydropyridines gave improved activity in vitro and in vivo. The piperazine derivative 12c and 12o were more than 10 times as potent as verapamil in vitro. Four compounds selected for in vivo testing showed superior antitumor activity in P388/VCR-bearing mice in combination with vincristine. The structure-activity relationships of the compounds are discussed.

Portal and systemic hemodynamic responses to a very low dose of nitroglycerin in cirrhotic patients with portal hypertension

Portal and systemic hemodynamic responses to a very low dose of nitroglycerin were studied in patients with portal hypertension and cirrhosis, and compared with those to a high dose of this compound. A 0.15 mg dose of nitroglycerin was given sublingually to 10 patients (LDG), and 0.3 mg to another 10 (HDG). Hemodynamic measurements were performed by means of hepatic venous and right cardiac catheterization before and 5 min after nitroglycerin administration. The wedged hepatic venous pressure decreased after dosing by 7.9% (p < 0.01) in LDG, and by 15.3% (p < 0.01) in HDG. Hepatic blood flow with ICG did not change in either group. In LDG, azygos blood flow remained unchanged, in contrast to a significant decrease by 10.1% (p < 0.05) in HDG. Mean arterial pressure fell by 3.6% (p < 0.05) in LDG and by 18.6% (p < 0.01) in HDG. Cardiac index did not change in LDG, but decreased by 11.4% (p < 0.05) in HDG. In both groups, mean pulmonary arterial pressure and pulmonary capillary wedge pressure fell significantly by the same amount. In HDG, a significant correlation between changes in wedged hepatic venous pressure and azygos blood flow (r = 0.70, p < 0.05) was observed. This suggested that splanchnic vasoconstriction mediated by a high-pressure, rather than a low-pressure, baroreceptor reflex was the main contributor to a decrease in portal venous blood flow, resulting in a reduction in wedged hepatic venous pressure; whereas a slight but significant fall of wedged hepatic venous pressure induced by a very low dose of nitroglycerin might have been due to venodilatation in the portal system and the hepatic vascular bed. These data suggest that, even with a very low dose of nitroglycerin, partial improvement of the hepatic circulation can be expected with minimal change in the systemic circulation in patients with cirrhosis and portal hypertension.

[Congestive (cardiac) cirrhosis]

As the incidence of cardiac cirrhosis at autopsy today is much lower than that from decades ago, true cardiac cirrhosis is a rare finding. With the decline in incidence of valvular disease, cardiomyopathy, in the etiology of congested liver, has increased. The pathophysiology of congestive heart failure consists of two components: forward failure with decreased hepatic blood flow and backward failure with congestive liver. Both lead to hepatocellular hypoxia. Increased serum transaminases and serum bilirubin correlate with reduction in cardiac output and elevation of venous pressure. Even when cardiac cirrhosis develops, it is difficult to diagnose clinically.

Plasma volume contraction in portal hypertension

The effect of blood volume contraction induced by a 4-week regimen of spironolactone (100 mg/day) or furosemide (40 mg/day) on the hepatic venous pressure gradient (HVPG), an indicator of portal hypertension, was evaluated in patients with cirrhosis and no ascites. In the spironolactone group (n = 15), HVPG decreased significantly from 16.5 +/- 0.9 mmHg (mean +/- S.E.M.) to 12.9 +/- 1.0 mmHg (P < 0.005) and total blood volume contracted significantly from 4338 +/- 231 ml to 4006 +/- 203 ml (n = 14, P < 0.01). Although the HVPG changes did not correlate significantly with changes in measured total blood volume or in simultaneously determined systemic haemodynamics, a significant inverse correlation (r = -0.74, P < 0.01, n = 12) was found between the HVPG change and posttreatment plasma aldosterone levels, attesting to the effectiveness of spironolactone therapy in lowering HVPG. In the furosemide group (n = 10), neither HVPG (13.7 +/- 0.3 mmHg vs. 13.6 +/- 0.9 mmHg) nor total blood volume (4961 +/- 153 ml vs. 4964 +/- 162 ml) declined significantly. These results show that long-term administration of spironolactone to patients with cirrhosis and no ascites produced a significant reduction in HVPG that may have been due to gradual, sustained volume contraction. Thus, spironolactone may prove to be an effective treatment for portal hypertension in cirrhosis without ascites.

Effects of alpha 1 and beta-adrenergic antagonists and 5-hydroxytryptamine receptor antagonist on portal-systemic collateral vascular resistance in conscious rats with portal hypertension

In order to study the acute effects of pharmacological agents on the vascular resistance of portal-systemic collaterals, a model of total portal vein occlusion with 100% portal-systemic shunts was developed in the conscious rat. The haemodynamic effects of several vaso-active substances were evaluated in this model and compared with those obtained after saline administration. Prazosin (0.5 mg), an alpha 1-adrenergic antagonist, significantly reduced mean arterial pressure by 29%, portal pressure from 13.8 +/- 1.0(mean +/- s.e.m.) to 10.1 +/- 0.4 mmHg and portal tributary blood flow (radioactive microspheres) from 13.6 +/- 2.1 to 11.7 +/- 1.2 mL/min. It also decreased portal-systemic vascular resistance from 95 +/- 16 to 73 +/- 9 dyn s/cm5 x 10(3). Propranolol (4 mg), a beta-adrenergic antagonist, significantly reduced mean arterial pressure by 12% and portal pressure from 15.5 +/- 1.2 to 13.3 +/- 0.9 mmHg while reducing portal tributary blood flow from 14.6 +/- 1.5 to 11.0 +/- 1.7 mL/min and increasing portal systemic collateral vascular resistance from 88 +/- 7 to 103 +/- 8 dyn s/cm5 x 10(3). Ketanserin (0.25 mg/kg), a 5-hydroxytryptamine receptor antagonist, reduced portal pressure from 15.8 +/- 1.0 to 13.3 +/- 0.7 mmHg at a dose that did not alter mean arterial pressure or portal tributary blood flow. It achieved this by reducing portal-systemic collateral vascular resistance from 90 +/- 14 to 74 +/- 13 dyn s/cm5 x 10(3). Saline had no significant effect on systemic and splanchnic haemodynamics. This study shows that ketanserin decreases vascular resistance of portal-systemic collaterals while propranolol increases it. Thus, it is suggested that collateral vascular resistance is accessible to pharmacological manipulation.

Long-term haemodynamic effects of a 4-week regimen of nipradilol, a new beta-blocker with nitrovasodilating properties, in patients with portal hypertension due to cirrhosis. A comparative study with propranolol

To study the long-term effects of pharmacological combination therapy, a comparison was made of the haemodynamic changes in patients with cirrhosis and portal hypertension following a 4-week treatment of propranolol or nipradilol, a new nonselective beta-blocker with nitrovasodilating effect. Nipradilol (12 mg/dag, n = 12) significantly diminished wedged hepatic venous pressure (WHVP, 25 +/- 16%), the hepatic venous pressure gradient (HVPG, 20 +/- 12%), and estimated hepatic blood flow (EHBF, 18 +/- 16%). Propranolol (30 mg/day, n = 11) also caused a significant reduction in WHVP (22 +/- 21%) and HVPG (24 +/- 21%), but not in EHBF. The percentage of portal pressure reduction and the frequency of nonresponders did not differ between the nipradilol and propranolol groups. Both agents reduced heart rate by approx. 20%. Nipradilol, however, did not cause a significant reduction in cardiac index (CI) versus a 14% reduction by propranolol. Pulmonary capillary wedge pressure and central venous pressure, an index of preload, were decreased slightly in the nipradilol group. When nonresponders were excluded, there was a significant correlation of the percentage of reduction between WHVP and CI or systemic vascular resistance, in the nipradilol group. These results indicate that nipradilol may have potent hypotensive effects on portal hypertension, similar but not superior to propranolol. Nipradilol, at the dosage used in the present study, did not appear to exert a nitrovasodilating effect to enhance the portal pressure reduction induced by beta-blocking action.

Reduction in hepatic venous pressure gradient as a consequence of volume contraction due to chronic administration of spironolactone in patients with cirrhosis and no ascites

The effect of plasma volume contraction induced by a 4-wk administration of spironolactone or furosemide on the hepatic venous pressure gradient was evaluated in consecutively allocated patients with cirrhosis and no ascites. In the spironolactone group (n = 15), the hepatic venous pressure gradient decreased significantly (p less than 0.005), by 21.8%, with a significant contraction of circulating plasma volume (p less than 0.01). Although there were no statistically significant correlations between the change in hepatic venous pressure gradient and changes in circulating plasma volume or in simultaneously determined systemic hemodynamics, a significant negative correlation (r = -0.74, p less than 0.01, n = 12) between the hepatic venous pressure gradient change and the post-treatment plasma aldosterone levels was found. However, in the furosemide group (n = 10), the hepatic venous pressure gradient and circulating plasma volume did not significantly decrease. Our data demonstrated a significant reduction in the hepatic venous pressure gradient on a chronic administration of spironolactone, which may have been due to volume contractions in patients with cirrhosis and no ascites.

Regional differences in peripheral circulation between upper and lower extremity in patients with cirrhosis

In 42 patients with compensated cirrhosis and 31 control subjects, blood flow (BF) and vascular resistance (VR) were measured at the forearm and calf, using a pneumoplethysmograph. In some of the subjects deep-body temperature (DBT) was also measured by the zero heat flow method. In cirrhosis, BF and DBT were significantly higher and VR was significantly lower in the forearm than in the calf. Corresponding differences were not observed in control subjects. When these indices of the forearm were compared between cirrhosis and controls, BF and DBT were significantly higher and VR was significantly lower in cirrhosis than in controls. In cirrhotics in whom the gradient between forearm BF and calf BF was 1 ml.dl-1.min-1 or more (forearm greater than calf), the vascular response of the forearm to cold stimulation was reduced, whereas in the remaining patients and in controls the forearm BF and VR responded significantly. These results suggest that there is a regional difference in peripheral circulation in cirrhotics, partly with participation of impaired sympathetic nervous activity, which may account for the selective distribution observed in the clinical manifestations of vascular spider, palmar erythema, and warm hand, inclined toward the upper extremities or the upper part of the body.

[Hepatic and systemic hemodynamics in compensated cirrhosis--effect of posture change]

The effect of changes in body posture on estimated hepatic blood flow (EHBF) and various hemodynamic parameters was examined in 15 patients with compensated cirrhosis. EHBF and various hemodynamic parameters were first measured with the patients in the supine position, and then again 10 min after tilting to 45 degrees. EHBF was 1089 +/- 315 ml/min at supine and 1065 +/- 328 after tilting; the difference was not significant. However, the patients were then divided into two groups according to the magnitude of the decrease in EHBF after tilting, with those showing a decrease of 10% of more assigned to group B, and those showing a decrease of less than 10% assigned to group A. It was found that ICG (R15) and BSP (R45) were significantly higher in group A. Meanwhile, among hepatic and systemic hemodynamics, wedged hepatic venous pressure, hepatic venous pressure gradient, free hepatic venous pressure, cardiac index, systolic blood pressure, systemic vascular resistance, and stroke volume were found to have changed significantly after tilting. These results suggest that posture change has no effect on EHBF in compensated cirrhotic patients.

Orthotopic liver transplantation with hepatic artery anastomoses. Hemodynamics and response to hemorrhage in conscious rats

Orthotopic liver isotransplantation was performed in one group of Lewis rats using cuffs for the portal vein and the infrahepatic vena cava, stents for the hepatic artery and the bile duct. Three other groups were also investigated: group A, normal rats; group B, sham-transplanted rats (clamping of the vessels, washing of the liver, placing cuffs around the portal vein); and group C, sham-transplanted rats with ligature section of the hepatic artery. Blood-flow measurements were performed, 1 week after the surgical procedure, with the radioactive microsphere method in conscious animals. Transplanted rats exhibited significant (ANOVA, P less than 0.05) increase in cardiac index and decrease in mean arterial pressure and systemic vascular resistance. Blood flows of the portal territory and to the kidneys were not significantly modified. Arterial liver blood flow and arterial liver vascular resistance in rats with liver transplantation were not significantly different between normal and sham-transplanted rats but were significantly different from rats with ligature of the hepatic artery. These results confirm the validity of the method used for vascular anastomoses. Hypotensive hemorrhage (2 ml/100 g bw) induced marked hemodynamic changes, but rats with liver transplantation when compared with normal and sham-transplanted rats exhibited the following: (a) significantly lower percentage of decrease in cardiac index and in mean arterial pressure; and (b) significantly higher renal and portal tributary blood flows. Plasma catecholamine concentrations and plasma volume were higher in rats with liver transplantation than in normal rats but were not significantly different from sham-operated rats. Histologic examination of the liver revealed slight portal edema in sham-operated rats and small necrotic areas in the liver, probably corresponding to the reperfusion injury, in rats with liver transplantation. In conclusion, the method described for the four vascular anastomoses allows functional perfusion of the transplanted liver. Rats with liver transplantation exhibited a hyperkinetic circulatory syndrome and an improved tolerance to hemorrhage. Changes in plasma catecholamine concentrations and in plasma volume did not account for the hemodynamic changes.

Effects of haemorrhage and volume expansion on portal-systemic collateral vascular resistance in conscious portal hypertensive rats

1. In order to study the acute effects of blood volume changes on the vascular resistance of portal-systemic collaterals (collateral vascular resistance), a model of total portal vein occlusion with 100% portal-systemic shunts was developed in the rat. In this model, we determined the haemodynamic effects of haemorrhage (1.8 ml/100 g body weight) or intravenous infusion of a volume expander (1.8 ml/100 g body weight). Cardiac output and regional blood flows were measured by the radioactive microsphere method. 2. Haemorrhage significantly reduced arterial pressure from 108 +/- 4 to 92 +/- 4 mmHg (mean +/- SEM), cardiac output from 56 +/- 4 to 24 +/- 2 ml min-1 100 g-1 body weight, portal pressure from 15.1 +/- 1.5 to 10.0 +/- 1.4 mmHg and portal tributary blood flow from 19.9 +/- 2.3 to 8.3 +/- 1.4 ml/min. Consequently, collateral vascular resistance significantly increased from 6.6 +/- 0.9 x 10(3) to 11.1 +/- 2.0 x 10(3) kPa 1(-1) s. 3. Volume expansion reduced arterial pressure from 98 +/- 3 to 90 +/- 3 mmHg, and significantly increased cardiac output from 43 +/- 3 to 55 +/- 3 ml min-1 100 g-1 body weight, portal pressure from 13.9 +/- 0.7 to 16.5 +/- 0.8 mmHg and portal tributary blood flow from 16.4 +/- 1.3 to 28.2 +/- 3.2 ml/min. Consequently, collateral vascular resistance significantly decreased from 7.0 +/- 0.5 x 10(3) to 4.9 +/- 0.4 x 10(3) kPa l-1 s. 4. This study shows that in rats with portal hypertension, portal-systemic collateral vascular resistance is modified by alterations in blood volume.

Hemodynamic effects of a combination of clonidine and propranolol in conscious cirrhotic rats

The hemodynamic effects of the combination of clonidine and propranolol were studied in conscious rats with portal hypertension owing to secondary biliary cirrhosis. Pressure and blood flow measurements (radioactive microsphere method) were performed in three groups of eight rats before and after drug administration. The combined effects of clonidine (2 micrograms/100 g body wt., i.v.) and propranolol (0.2 mg/min for 10 min) were compared with those observed after administration of either clonidine alone or propranolol alone. The association of clonidine and propranolol induced significant decreases in portal pressure (30%) and portal tributary blood flow (43%), the magnitude of these changes being significantly more marked than that after administration of either clonidine alone (12 and 20%, respectively) or propranolol alone (16 and 17%, respectively). After the combination, no significant change in arterial pressure was observed, but cardiac output significantly decreased and systemic vascular resistance significantly increased. Renal blood flow decreased to a similar extent (40%) in the three groups. These findings indicate that the combination of clonidine and propranolol is more effective for reversing splanchnic hemodynamic changes than clonidine alone or propranolol alone. The additive effects of this association are in agreement with the action of clonidine and propranolol at different levels (central and peripheral) and on different receptors (alpha and beta). It suggests that an increase in sympathetic activity may play a major role in hemodynamic changes observed in experimental cirrhosis.