Small bowel transplantation in mice

Since 1990, the development of tacrolimus-based immunosuppression and improved surgical techniques, the increased array of potent immunosuppressive medications, infection prophylaxis, and suitable patient selection helped improve actuarial graft and patient survival rates for all types of intestine transplantation. Patients with irreversible intestinal failure and complications of parenteral nutrition should now be routinely considered for small intestine transplantation. However, Survival rates for small intestinal transplantation have been slow to improve compares increasingly favorably with renal, liver, heart and lung. The small bowel transplantation is still unsatisfactory compared with other organs. Further progress may depend on better understanding of immunology and physiology of the graft and can be greatly facilitated by animal models. A wider use of mouse small bowel transplantation model is needed in the study of immunology and physiology of the transplantation gut as well as efficient methods in diagnosing early rejection. However, this model is limited to use because the techniques involved is an extremely technically challenging. We have developed a modified technique. When making anastomosis of portal vein and inferior vena cava, two stay sutures are made at the proximal apex and distal apex of the recipient s inferior vena cava with the donor s portal vein. The left wall of the inferior vena cava and donor s portal vein is closed with continuing sutures in the inside of the inferior vena cava after, after one knot with the proximal apex stay suture the right wall of the inferior vena cava and the donor s portal vein are closed with continuing sutures outside the inferior vena cave with 10-0 sutures. This method is easier to perform because anastomosis is made just on the one side of the inferior vena cava and 10-0 sutures is the right size to avoid bleeding and thrombosis. In this article, we provide details of the technique to supplement the video.     

THE SURGICAL TREATMENT OF PORTAL HYPERTENSION

Portacaval shunt operations were done in 15 of 18 patients who were treated surgically for portal hypertension. In eight cases the shunt was established by splenorenal anastomosis; in seven by anastomosis of the portal vein to the side of the inferior vena cava. Of the eight patients with splenorenal shunt, two are well, four are considered improved, and two have died. Of the seven in whom the portal vein was joined to the vena cava, two are improved, one is unimproved, and four have died.     

Orthotopic Kidney Transplantation in Mice: Technique Using Cuff for Renal Vein Anastomosis

Mouse renal transplantation is a technically challenging procedure. Although the first kidney transplants in mice were performed over 34 years ago and refined some years later, the classical techniques of mouse renal transplantation required clamping both vena cava and aorta simultaneously and carry out suture anastomoses of the renal artery and vein in a heterotopic position. In our laboratory, we have successfully developed mouse orthotopic kidney transplantation for the first time, using a rapid “cuffed” renal vein technique for vessel anastomosis, wherein the donor’s renal vein was inserted through an intravenous catheter, folded back and tied. During grafting, the cuffed renal vein was directly inserted into the recipient’s renal vein without the need for the clamping vena cava and suturing of renal vein. This technique allowed for the exact transplantation of the kidney into the original position, compared to the classical technique, and has significantly shortened the clamping time due to a quicker and precise anastomosis of renal vein as described. This also allowed for a quicker recovery of the lower extremity activity, reduction in myoglobinuria with resultant kidney graft survival of 88.9%. Thus we believe that the cuffed renal vein technique simplifies microvascular anastomoses and affords important additional benefits.     

On the presence of a ductus venosus in the fetal pig in late gestation

Evidence is presented to show that there is a functional bypass in the liver of the fetal piglet between the umbilical vein and the posterior vena cava. Injections of labelled microspheres (14 micrometer) into the umbilical vein in six fetuses in late gestation resulted in the appearance of radioactivity in the arterial blood and throughout the tissues of all piglets. About 60% of the umbilical venous blood bypassed the liver whereas in a fetal foal, injection in a similar manner, no evidence for a shunt was found. Radiographic studies confirmed the presence of a large vascular connection, equivalent to the ductus venosus, between the umbilical vein and posterior vena cava in the fetal piglet.     

A simplified method for metabolic studies in conscious swine

Reliable short-term blood access in conscious swine was provided by implanting multiple silastic catheters. Catheters were inserted into the aorta, hepatic vein, portal vein, and inferior vena cava through a midline laparotomy incision. Multiple catheters also were placed into the external jugular vein through a separate cervical incision. Catheter patency rates for blood withdrawal on the sixth post-operative day were: arterial 100%, hepatic 91%, portal 86%, inferior vena cava 71%. No animal had major wound or catheter infection on the seventh post-operative day. The methods described allow metabolic studies, including measurements of splanchnic blood flow, to be carried out either acutely or for up to at least 7 days post-operatively.     

环颈雉胃的血供

用血管铸型法和大体解剖学方法对环颈雉胃动脉的起源、分布及胃静脉的回流情况进行了解剖学研究。结果表明,环颈雉的胃动脉均由腹腔动脉分出;腺胃由腺胃背侧动脉和腺胃腹侧动脉营养,腺胃背侧动脉直接起自腹腔动态的左侧,腺胃腹侧动脉起自腹腔动脉左支。腺胃血液的静脉有腺胃前静脉和腺胃后静脉,分别汇入后腔静脉和左肝门静脉。肌胃由肌胃左动脉、肌胃右动脉和肌胃背侧动脉营养,肌胃左动脉起自腹腔动脉的左支;肌胃右动脉起自腹腔动脉的右支;肌胃背侧动脉从腺胃背动脉分支而来。回流肌胃血液的静脉有胃右静脉、胃左静脉和胃腹侧静脉;胃右静脉汇入右肝门静脉,胃左静脉和胃腹侧静脉汇入左肝门静脉。另外腺胃和肌胃的表面缺乏主干动脉间的吻合。     

Problems associated with the measurement of mean circulatory filling pressure by the atrial balloon technique in anaesthetized rats.

To examine the existence of pressure equilibrium between tributary veins and the central vena cava during the mean circulatory filling pressure manoeuvre, pressures in the hepatic portal vein, renal vein, and inferior vena cava were determined at 4-s intervals over a 20-s period of circulatory arrest induced by inflating a right atrial balloon in normal blood volume, 10% volume depletion, and 10% volume expansion states in urethane-anaesthetized rats. Portal vein pressure determined 8 s after arrest during volume depletion and expansion was significantly higher than vena caval pressure (6.2 +/- 0.8 vs. 3.4 +/- 0.2 and 7.7 +/- 0.5 vs. 6.2 +/- 0.4 mmHg (1 mmHg = 133.32 Pa), respectively; p less than 0.01); this pressure disequilibrium continued for 16 s during volume expansion and for the entire 20 s during volume depletion. Renal vein pressure was equal to vena caval pressure during this manoeuvre. Portal vein pressure at normal blood volume was not significantly different from vena caval pressure following circulatory arrest (4.6 +/- 0.3 vs. 3.8 +/- 0.4 mmHg, respectively). Following ganglionic blockade, portal vein pressure was still significantly higher than vena caval pressure for 12 s during volume alterations. At the 8th s of the arrest the portal pressure determined in volume depletion was 3.6 +/- 0.3 mmHg and the inferior vena caval pressure was 2.6 +/- 0.4 mmHg (p less than 0.05). Under the volume expansion condition, the respective values were 6.5 +/- 0.3 and 5.3 +/- 0.4 mmHg (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Contractile responses to prostacyclin (PGI2) of isolated human saphenous and rat venous tissue.

Prostacyclin (PGI2), in a wide concentration range, produced neither contraction nor relaxation of isolated human saphenous vein. Isolated portal veins and vena cava from normal and spontaneously hypertensive rats (SHR) responded only with an increase in contractile tension when exposed to PGI2. This constrictor effect was absent in a calcium-free buffer. PGI2 failed to relax KCI contracted vena cava. The constrictor effect of PGI2 on portal vein was attenuated in a glucose-free, oxygen deficient buffer. No tachyphylaxis or tolerance to the constrictor effect of PGI2 was noted. Results emphasize that PGI2 may produce differing effects on vascular smooth muscle tension depending on species and type of blood vessel studied.     

The effect of oxytocin treatment on the levels of prostaglandin F in the blood of heifers

Six heifers with normal oestrous cycles were treated i.m. with 100 i.u. oxytocin on 3 consecutive days, commencing on Days 1-6 after oestrus, and the levels of prostaglandin (PG) F in posterior vena cava plasma were compared with pretreatment values. An increase of PGF in response to oxytocin was significantly influenced by day, with the greatest response occurring on Day 3 after oestrus. In an ovariectomized heifer the levels of PGF in posterior vena cava plasma increased 24 h after priming with oestradiol, but no further increase occurred after oxytocin injection. Peak levels of PGF were higher in the plasma of the posterior vena cava than in the jugular vein. Various storage conditions of the blood before centrifugation and freezing (--20 degrees C) produced significant differences in plasma levels of endogenous PGF, but storage experiments with added labelled PGF-2alpha indicated that the PG was stable in plasma and whole blood.     

Evidence for the secretion of immunoreactive neurophysin I in addition to oxytocin from the ovary in cattle

In Exp. I, blood samples were collected simultaneously from the posterior vena cava and jugular vein or aorta from 7 heifers every 5-20 min for 2-5 h. Concomitant pulsatile secretion of oxytocin and immunoreactive neurophysin I was detected in the vena cava, but not in the jugular vein or aorta. Concentrations of oxytocin and immunoreactive neurophysin increased earlier and were higher in the vena cava than in the jugular vein or aorta after the injection of a luteolytic dose of prostaglandin F-2 alpha analogue during the mid-luteal phase of the oestrous cycle, demonstrating its ovarian but not pituitary origin. In Exp. II, blood samples were collected from the jugular vein every 12 h during 1 week after oestrus. Follicular growth had been stimulated during the preceding oestrous cycle with PMSG (10 heifers and cows) or with FSH (5 animals); 6 heifers served as controls. There was a high correlation between the number of follicles or CL and the increase in oxytocin and immunoreactive neurophysin I. Although PMSG had a greater luteotrophic effect than did FSH on progesterone secretion, a similar stimulation of oxytocin and immunoreactive neurophysin I was not observed. It is concluded that immunoreactive neurophysin I and oxytocin are secreted from the ovary in concentrations dependent upon the number of corpora lutea (and of follicles) present. During the mid-luteal period the secretion occurs in a concomitant pulsatile fashion.     

Inherited liver shunts in dogs elucidate pathways regulating embryonic development and clinical disorders of the portal vein

Congenital disorders of the hepatic portal vasculature are rare in man but occur frequently in certain dog breeds. In dogs, there are two main subtypes: intrahepatic portosystemic shunts, which are considered to stem from defective closure of the embryonic ductus venosus, and extrahepatic shunts, which connect the splanchnic vascular system with the vena cava or vena azygos. Both subtypes result in nearly complete bypass of the liver by the portal blood flow. In both subtypes the development of the smaller branches of the portal vein tree in the liver is impaired and terminal branches delivering portal blood to the liver lobules are often lacking. The clinical signs are due to poor liver growth, development, and function. Patency of the ductus venosus seems to be a digenic trait in Irish wolfhounds, whereas Cairn terriers with extrahepatic portosystemic shunts display a more complex inheritance. The genes involved in these disorders cannot be identified with the sporadic human cases, but in dogs, the genome-wide study of the extrahepatic form is at an advanced stage. The canine disease may lead to the identification of novel genes and pathways cooperating in growth and development of the hepatic portal vein tree. The same pathways likely regulate the development of the vascular system of regenerating livers during liver diseases such as hepatitis and cirrhosis. Therefore, the identification of these molecular pathways may provide a basis for future proregenerative intervention.     

Effect of the Warren operation on hypersplenism]

The authors present their own comments on the effect of Warren shunt on hypersplenism. Hypersplenism is frequent complication in portal hypertension. The authors estimate its frequency on 64.7% of patients. Spleen size, thrombocyte count, WBC count, and esophageal endoscopy have been carried out prior to and following distal spleno-renal shunt. Surgery produced favourable effect in 70% of patients, i.e. a decrease of hypersplenism symptoms. An increase in blood platelet count may serve as a screening marker of anastomosis patency.     

Participation of the cava vein blood flow in forming the total venous return under influence of different modality stimuli on the circulation system

Participation of the anterior and posterior veins cava in forming the total venous return under pressor and depressor effects, stimulation of depressing foci of the medulla's ventral part, enhancement of pulmonary ventilation, hypoxia, hypothermia, administration of acetylcholine, histamine, corinfar, was shown to depend on the blood flow shift direction in each of the veins cava, dynamics of shifts' development in time, and intensity of the stimulus. In systemic responses, the blood flow shifts in the vena cava anterior much contribute to the total venous return at the maximum of the systemic arterial pressure rise (r = 0.87) whereas contribution of the vena cava posterior is the greatest during a later occurring increase in the venous return (r = 0.84). Along with increase in the stimulus intensity the vena cava anterior's part in forming the venous return becomes more limited whereas that of the vena cava posterior is enhanced.     

Simultaneous collection of the portal and superior vena cava blood in conscious rats defined that intestinal epithelium is the major site of glucuronidation,but not sulfation and methylation,of quercetin

ABSTRACT

Quercetin is a flavonoid with many physiological effects. Absorbed quercetin is rapidly conjugated in the intestinal epithelium and liver. Different positional isomers of quercetin conjugates have different physiological properties. However, the mechanisms of quercetin conjugation in the intestine are not fully clarified. We examined the regioselective quercetin conjugate formation in the intestine after oral administration of quercetin glycosides, by simultaneous sampling of blood from the portal vein and superior vena cava, and quantifying various positional isomers of quercetin glucuronides and sulfates in conscious rats. Concentrations of quercetin glucuronides were higher in blood from the portal vein than the superior vena cava, showing that glucuronidation mainly occurred in the intestine. Such differences were not observed for quercetin sulfates. Regioselectivity of the intestinal glucuronidation in quercetin hydroxyl groups were 7- >3′- >3- >4′-OH. Quercetin was mainly sulfated on 3′-OH at 30 min, but on 4′-OH at 240 min.     

Contractile responses to prostacyclin (PGI2) of isolated human saphenous and rat venous tissue

Prostacyclin (PGI₂), in a wide concentration range, produced neither contraction nor relaxation of isolated human saphenous vein. Isolated portal veins and vena cava from normal and spontaneously hypertensive rats (SHR) responded only with an increase in contractile tension when exposed to PGI₂. This constrictor effect was absent in a calcium-free buffer. PGI₂ failed to relax KCI contracted vena cava. The constrictor effect of PGI₂ on portal vein was attenuated in a glucose-free, oxygen deficient buffer. No tachyphylaxis or tolerance to the constrictor effect of PGI₂ was noted. Results emphasize that PGI₂ may produce differing effects on vascular smooth muscle tension depending on species and type of blood vessel studied.     

Simultaneous sampling of portal, hepatic and systemic blood during intragastric loading and tracer infusion in conscious pigs

A surgical model for catheterization at multiple sites has been developed for use in long-term metabolic studies. For blood sampling, catheters were inserted into the portal and hepatic veins and the common carotid artery. The hepatic vein catheter was inserted from the margin of a liver lobe and led through the venous system, until the tip was close to the bifurcation with the inferior vena cava. A new technique was developed to ensure correct placement of the hepatic vein catheter using the specific extraction of indocyanin-green over the liver during surgery. Gastrostomy was performed using a Pezzer catheter. Catheters in the artery and hepatic and portal veins were patent for blood withdrawal for up to 4 weeks, and thus allowed repeated metabolic studies. Studies were performed in conscious animals familiar with the experimental situation.     

Orthotopic Liver Transplantation in Rats

Clinical progress in the field of liver transplantation has been largely supported by animal models^1,2. Since the publication of the first orthotopic rat liver transplantation in 1979 by Kamada et al.³, this model has remained the gold standard despite various proposed alternative techniques⁴. Nevertheless, its broader use is limited by its steep learning curve⁵.In this video paper, we show a simple and easy-to-establish revision of Kamada''s two-cuff technique. The suprahepatic vena cava anastomosis is performed manually with a running suture, and the vena porta and infrahepatic vena cava anastomoses are performed utilizing a quick-linker cuff system⁶. Manufacturing the quick-linker kit is shown in a separate video paper.     

Morphologic and surgical indications for temporary partial occlusion of the inferior vena cava by soft clipping

In the experiment performed on 72 dogs peculiarities of morphological changes in the posterior vena cava wall have been studied at a temporal disturbance of blood flow in it by means of a complete or partial ligation of the vessel with catgut, a complete or partial closing of the lumen of the vein by means of a wavy catgut clip, covered with glue MK-6. Predominance of the soft clipping at the temporal disturbance of the blood flow in the vein with the aim of prophylaxis of thromboembolism of the pulmonary artery has been demonstrated. At the soft clipping in the place of the vascular compression, the blood flow partially remains, thrombi in the lumen do not form, rough dystrophic and necrotic changes in the vein are absent, that is the organ preservation of the vein is ensured. In 1.5 months the vascular lumen is completely restored, and structure of its wall at the place of compression does not differ from the normal one.     

The Vascularization of the Anuran Brain: The Mesencephalon

The angioarchitecture of the toad's mesencephalon is studied by scanning electron microscopy of vascular corrosion casts. The arterial supply is performed by the superior mesencephalic artery and by an artery arising from the ramus posterior of the arteria carotis cerebralis just in front of the retroin-fundibular communicating artery. The venous drainage is exerted by the vena diencephalica, the vena lateralis mesencephalis and by anterior and posterior branches of the encephaloposthypophysial portal vein. Characteristics of the mesencephalic angioarchitecture are the centrifugal direction of the blood flow, the intensive capillarization, and the formation of vascular meshworks in the region of the stratum griseum periventriculare tecti and of the stratum griseum superficiale tecti.     

Contribution of the umbilical and portal veins to the hepatic blood supply of guinea pig fetuses--an angiographic study.

The interlobular distribution of the umbilical and portal venous blood flow within the liver was examined in 35 guinea pig fetuses between 59 and 65 days of gestation. Contrast medium was injected into the umbilical or vitelline vein, and its passage through the liver was monitored by serial angiography. In four experiments, injections were made into both the umbilical and vitelline veins of the same fetus. To ease interpretation of the angiograms obtained in vivo, we also made a postmortem examination of livers in which the venous system had been filled with an aqueous suspension of barium sulphate in gelatin. These combined experiments demonstrated no passage of contrast medium from the placenta to the inferior vena cava, which is in accordance with independent evidence that the term guinea pig fetus lacks a functional ductus venosus. The area supplied by the umbilical and portal veins was clearly and consistently delineated. The umbilical vein supplied the left lobe and the left sublobe of the quadrate lobe. The portal vein supplied the right lobe, the smaller caudate lobe, and all or most of the right sublobe of the quadrate lobe. This pattern of distribution appears to be determined by flow and pressure gradients within the hepatic circulation.