Experimental atrophy/hypertrophy complex (AHC) of the liver: portal vein, but not bile duct obstruction, is the main driving force for the development of AHC in the rat.

BACKGROUND/AIMS: Patients with lobar or segmental impairment of bile flow or of portal venous blood flow frequently develop considerable atrophy of the area involved, followed by compensatory hypertrophy/hyperplasia of the non-affected parts. This configuration is termed atrophy/hypertrophy complex of the liver. METHODS: In order to analyze the relative contributions of bile duct and portal vein obstruction in the pathogenesis of atrophy/hypertrophy complex, we developed a rat model with selective bile duct and/or portal vein ligation of the anterior liver lobes, representing about two thirds of the liver mass. Evolution of total body weights and weights of the different liver lobes were determined, and morphometry and functional scintigraphy (hepatoiodida scanning) were performed immediately after ligation and at 30 h, 4, 8 and 28 days postoperatively. RESULTS: The major findings were: 28 days after biliary and/or portal ligation there was no difference between the body weights of all animals, all ligated animals having compensated an initial body weight loss. Total liver weight remained constant during the whole observation period, while atrophy of the anterior and hypertrophy/hyperplasia of the posterior lobes occurred. A significant atrophy/hypertrophy complex developed only after selective portal ligation, but not after selective biliary ligation. Morphometrically analyzed histologic changes after selective biliary ligation were reversible, whereas in portally ligated liver lobes a progressive parenchymal destruction and involution with subsequent impairment of hepatic function of the concerned lobe were observed. CONCLUSIONS: The present findings indicate that impairment of portal venous flow is the major driving force for the development of lobar atrophy in the rat and that atrophy/hypertrophy complex can be produced in a rodent model.

Experimental assessment of thrombogenicity in vascular prostheses before and during prostaglandin E1 treatment.

The effect of prostaglandin E1 (PGE1; Prostavasin), a powerful platelet blocking agent, was assessed on various new synthetic or biological prostheses in a 6-min in vivo extra corporal arterio-venous (AV) shunt. In eight anaesthetised and heparinised minipigs (weight 25.1 +/- 1.9 kg) the following materials were tested before and during PGE1 infusion (alprostadil-alpha-CD; 40 micrograms/50 ml NaCl/50 min or 0.8 microgram/min): PTFE, (Gore-tex, TW, 4 mm ID); Xenograft, Biologic (Solcograft, 5 mm ID), (non-porous) and Dacron (Atrium, 4 mm ID); polyurethane 1 (Braun-Melsungen, 4 mm ID); polyurethane 2 (S. Gogolewski, 4 mm ID), (porous). Technetium-labelled platelet deposition and blood flow were measured; morphology was assessed by scanning electron microscopy (SEM) and histology. Compared to control levels, PGE1 infusion had a significant systemic effect on mean arterial pressure required by the protocol (MAP 82.6 vs. 66.6 mm Hg; p < 0.001) and flow (173.6 vs. 134.8 mm/min; p < 0.001). Standardised platelet counts per area showed a marked overall decrease from 197 to 130 counts/min/mm2; NS). The morphological assessment by SEM showed a slight increase of surface cellular deposition (score: 6.7 vs. 8.3), the histology score being unchanged (3.9 vs. 3.7). Looking at deposition of platelets for each prosthesis, the porous materials showed a net improvement after PGE1 treatment as compared to non-porous materials. We conclude that PGE1 may be of benefit by reducing platelet deposition in synthetic porous vascular prostheses in the early phase.

[Radiologic and nuclear medicine diagnosis of lung embolism]. / Radiologische und nuklearmedizinische Diagnose der Lungenembolie.

The imaging methods used in diagnosing pulmonary embolism and their appropriate indication in individual situations are discussed. Chest radiography is needed to exclude other diseases, whereas nuclear ventilation and perfusion scans are the main screening method and have not been replaced by intravenous digital subtraction angiography up to now. As long as these non-invasive methods are clearly negative or positive, no other method is needed. With questionable findings (intermediate scan probability), pulmonary angiography is needed, above all when there is a contraindication to anticoagulation.

[Experimental atrophy/hypertrophy complex of the liver after portal and/or biliary ligation in the rat]. / Experimenteller Atrophie/Hypertrophie-Komplex der Leber nach portaler und/oder biliärer Ligatur bei der Ratte.

Patients with lobar or segmental, benign or malignant strictures of the biliary tree (with or without impairment of the portal blood flow) show a considerable atrophy of the involved area of the liver with a compensatory hypertrophy/hyperplasia of the remaining non affected liver. To investigate the importance of the biliary and portal obstruction for the development of this process, we used a rat model, with selective biliary and/or portal ligation of the anterior liver lobes (two thirds of the liver mass). Weight measurements, morphometry, functional scintigraphy (Hepatoiodida-scan) and blood enzyme analyses were done immediately postoperatively, at 30 hours and 4, 8 and 28 days after the operation. The major findings were: 1. 28 days after biliary and/or portal ligation there was no difference between the body weight of the four groups, all ligated animals having compensated for an initial greater percentage body-weight loss. 2. Total liver weight remained constant, while atrophy and hypertrophy/hyperplasia occurred although a progressive derangement of liver morphology was observed during that time. 3. A severe atrophy-hypertrophy-complex (AHC) developed after selective portal ligation, which in our experiment did not appear after selective biliary ligation. 4. Morphometrical changes after selective biliary ligation were reversible, whereas in liver lobes with selective portal ligation a progressive parenchymal destruction and involution with subsequent impairment of hepatic function of the concerned lobe was observed.

Reversibility of secondary biliary fibrosis by biliodigestive anastomosis in the rat.

Biliary cirrhosis with portal hypertension and hepatocellular failure is a well-known complication of extrahepatic obstruction. It is unclear to what extent these changes are reversible by biliodigestive anastomosis. Therefore a rat model of relief of biliary obstruction was developed by performing Roux-en-Y choledochojejunostomy in rats after bile duct obstruction. Patency of the biliodigestive anastomosis was documented by biliary scintigraphy. Microsomal function was assessed in vivo by the aminopyrine breath test and portal hypertension by spleen pulp pressure. Microsomal function was markedly impaired in obstructed animals but recovered after biliodigestive anastomosis. Microsomal cytochrome P450 content paralleled these changes. Similarly, portal hypertension was reversed after successful relief of obstruction. Stereologic analysis showed that biliodigestive anastomosis partially reversed bile ductular proliferation and fibrosis. Studying the time course of recovery showed that restoration of microsomal function was achieved after 2 weeks whereas recovery from portal hypertension required 4 weeks of biliary drainage. Recovery of microsomal function was paralleled by normalization of microsomal lipid composition while resolution of portal hypertension occurred parallel to resolution of the histologic abnormalities.

[Evaluation of recent vascular prostheses in the arteriovenous shunt]. / Erprobung neuer Gefässprothesen im arterio-venösen Shunt.

Prosthetic vascular replacement materials are still suboptimal especially for distal peripheral and coronary bypass grafts due to the small caliber and high occlusion rates. Therefore new vascular grafts have been assessed with respect to blood compatibility, thrombogenicity and host pretreatment. In 12 heparinized minipigs (25 kg), a total of 120 small caliber grafts (i.d. 3.0 mm) were perfused (6 min) in a femoro-femoral arteriovenous shunt (AVS). Materials included: Dacron (Atrium), PTFE (Gore), Polyurethanes (PU), Auto- and Xenografts. Animals were treated preoperatively with fishoil (3 g EPA/QD x 3 weeks = group I), perioperatively with prostaglandins (PGE1 = group II) or with fishoil and graft incubation in plasma proteins (= group III) and compared to controls without pretreatment (= group 0). We measured flow, deposition of marked thrombocytes (HMPAO-Tc* per area and per weight). - Blood flow was similar in AVS for all groups and materials (168 +/- 86 ml/min, p = NS). There was no significant correlation in deposition of marked thrombocytes and host pretreatments (group 0: controls = 7356 counts/area, group I: fishoil = 6807. group II: PGE1 = 7864). However graft incubation in plasma proteins significantly lowered deposition of marked thrombocytes (1766 in group III vs. 7356 in group 0: p less than 0.05). And significant differences of thrombocyte counts where found between the different materials: Autografts less than PTFE less than Xenografts less than Small Pore PU less than Dacron less than Large Pore PU.--AVS is a useful tool to determine early thrombogenicity in prosthetic vascular replacement materials and to assess the effect of different host pretreatments.

Routine 18F-2-deoxy-2-fluoro-D-glucose (18F-FDG) myocardial tomography using a normal large field of view gamma-camera.

There is a recent need to study glucose metabolism of the heart in ischemic, as well as in "hibernating or stunned" myocardium, and compare it with that in perfusion studies. In non-positron emission tomography centers, positron imaging is possible with a standard Anger-type camera if proper collimation and adequate shielding of the camera crystal can be achieved. For the study with fast-decaying isotopes, seven-pinhole tomography (7PHT), a limited-angle method designed for transaxial tomography of the left ventricle using a nonrotating camera, is well suited, because projections are acquired simultaneously. Individual adjustment (patient supine) of the camera's view axis (CAx) with the left ventricular axis (LVAx) gives excellent results: sensitivity for CHD 82%, specificity 72% in a prospective 201TI study (48 patients, x-ray coronarography as reference). Good alignment of CAx with LVAx is also achieved with the patient prone in LAO in a hammock above the camera surface. In this setting additional lead shielding of the camera is possible using a table reinforced with 5 cm of lead with a central hole for the 7PH-collimator, which has a special lead inlay. This allows utilization of the 511 KeV emitter 18F-FDG, which with a half-life of 109 minutes, can be transported a reasonable distance from the production site. System sensitivity and resolution for 18F was found comparable to 201Tl, 99mTc, and 123I using a phantom. First clinical examinations after 201Tl stress/redistribution studies showed increased 18F-FDG uptake in ischemic heart segments, as well as in "hibernating" nonperfused or "stunned" myocardium.

Comparative diagnostic value of a new computerized vectorcardiographic method (cardiogoniometry) and other noninvasive tests in medically treated patients with chest pain.

The diagnostic value of cardiogoniometry (CGM), a new computerized vectorcardiographic method, for the identification of coronary artery disease was compared with other noninvasive tests in 48 medically treated patients with chest pain. Coronary angiography revealed one-vessel disease in 18, two- or three-vessel disease in 21, and normal coronary arteries in 9 patients. Cardiogoniometry was less sensitive (63%) than thallium-201 (201T1) scanning (82%), but slightly more sensitive than the exercise ECG (50%) or a recently proposed parameter of exercise performance (50%). On the other hand, specificity was comparable among these tests (exercise ECG 78%, thallium-201 scanning 72%, CGM 67%, new parameter of exercise performance 66%). Moreover, the false negative rate of noninvasive testing was reduced from 8 to 3% when CGM was added to thallium-201 scanning and exercise ECG. Our findings indicate that in view of the easier feasibility with computerized technology, the future role of vectorcardiographic methods such as CGM in the noninvasive diagnosis of coronary artery disease should be redefined.

Experimental pancreaticosplenic composite transplantation in the pig. Operative technique and assessment of graft function.

A large animal model for substitutive pancreaticosplenic composite transplantation with urinary drainage to the bladder has been developed in the pig. Transplantations were performed in 7 nontissue-typed donor-recipient combinations without immunosuppressive medication. Six recipients showed perfect graft function at least until the 5th postoperative day. Blood glucose, intravenous glucose tolerance tests and urine amylase concentrations proved to be sensitive markers of graft function. Scintigraphic follow-up examination with 99mTc tin colloid could only record perfusion of the splenic transplantation. With this model the role of the spleen in pancreaticosplenic composite transplantations can be studied in forthcoming experiments.

Pneumatosis cystoides coli recurs after oxygen treatment. A clue to the pathogenesis?

Two patients with pneumatosis cystoides coli associated with chronic pulmonary disease are described. In both patients, cysts and symptoms recurred after successful treatment with O2. Both patients had exceptionally high expiratory H2 fasting values. On the basis of these and other observations a new hypothesis is proposed for the pathogenesis of the cysts and for their frequent association with chronic pulmonary disease. It is suggested that the cysts result from excessive colonic gas production in a patient unable to excrete this excess gas via the lungs.

The importance of proper adjustment of safety bindings.

The ski bindings in 50 consecutive patients with fractures of the lower leg were tested. All patients had broken the leg while skiing at two of Sweden's most popular ski resorts. There were 21 boot top fractures, 20 spiral fractures of the tibial shaft, eight malleolar fractures, and one fracture of the lateral tuberosity of the tibia. The tension required for release of the bindings laterally at the toe and vertically at the heel was measured and compared with the values recommended by the International Association for Skiing Safety. The ski bindings in no less than 49 of the 50 patients did not release in both directions at a tension 10 per cent higher than the recommended values. The ski bindings of 50 skiers randomly taken from a ski lift queue at one of the ski resorts studied were tested for comparison. The bindings in 48 of these 50 persons were found to be overadjusted; i.e., their bindings did not release in both directions at values comparable to those recommended by IAS. An analysis of the series stresses the need for bindings releasing also laterally at the heel, with a consistent release mechanism and a tamperproof tension adjustment screw.

Effect of flow material ski boots on foot circulation.

The effect of modern "flow material" ski boots on foot circulation was studied. Pressure inside a flow material ski boot was found to be markedly higher than in a conventional ski boot. In some places the pressure exceeded the diastolic pressure in the foot. 113mIndium chloride, which when injected intravenously is bound to transferrin was used for blood pool scanning. In healthy young volunteers the uptake of radioactivity in the two feet--one with and one without a ski boot--was compared. The activity level of the foot with the ski boot was significantly lower than in the other foot. After corrections were made for absorption by the boot, a significant difference remained. Plethysmographic studies were performed with a mercury strain gauge using a ski boot in which a hole was cut over the big toe. No difference was demonstrated between the blood pressure at the leg just above the boot top and at the big toe. The arterial pulse wave at the big toe was altered; i.e., there was an absence of a dichrotic wave. Intramuscular perfusion was studied with 133xenon. The disappearance curve in a foot with a boot was more shallow than that in a bare foot. Unbuckling resulted in an immediate fall in radioactivity, the disappearance curve then becoming identical to that of the bare foot. The results indicate that when flow material ski boots are to be used by skiers who are not in the habit of unbuckling for short intervals, buckle tension should not be too high.

Boot top fractures.

Low transverse fractures of the tibiofibular complex due to ski injuries were formerly virtually unknown but are now met in ever increasing numbers. A series of 126 such fractures occurring in patients 13 years or older was analyzed. The sex and age distributions of these patients were found to differ significantly from those in skiers with other tibial shaft fractures. Among boot top fractures cases, boys younger than 20 years predominated much more than among patients with other fractures of the tibial shaft. In the boot top fracture there is characteristically a backward angulation, which may be combined with a forward displacement of the distal fragment. A simple technique for reduction of this typical deformity is described. According to this technique the surgeon should take a steady grip on the foot held in extreme plantar flexion. By applying strong traction, disimpaction is achieved after which the distal fragment is forced back into position and the fracture is immobilized with the foot in full equinus. This technique was successfully applied in the majority of our cases (112 of 126). Patients with boot top fractures were hospitalized for shorter periods than were skiers with other tibial fractures, and they were able to resume their normal activities much sooner. This held true even when allowance was made for differences in age. During the last few years a new type of boot top fracture has been observed. In this type there is a forward instead of a backward angulation. Its occurrence is most probably related to the new "scoot foot" or "sitting back" technique in downhill skiing. The appearance of this new type of boot top fracture implies that successful prevention can be achieved only with safety bindings that release not only at rotation but also when the skier falls backward.