[Microcirculation changes of three yin-meridians of hand in the forearm in rabbits with arrhythmia: a comparative study].

OBJECTIVE: To observe the microcirculation changes of three yin-meridians of hand in the forearm in rabbits with arrhythmia, and to compare the differences of responses among the three yin-meridians of hand. METHODS: A total of 20 New Zealand rabbits were randomly divided into a saline group and a model group, 10 rabbits in each one. The rabbits were anesthetized with intravenous injection of 20% ethyl carbamate (3.3 mL/kg) at ear vein; the saline group was injected with 0.9% sodium chloride solution (1 mL/kg), while the model group was injected with 0.4% barium chloride solution (1 mL/kg) to establish the arrhythmia model. The microcirculation changes of the three yin-meridians of hand were observed and analyzed by laser speckle blood flow imaging technique before and after the intervention. RESULTS: Compared before modeling, the microcirculation perfusion of the three yin-meridians of hand in the model group was significantly reduced (P<0.01), and the reduction in the jueyin meridian was more significant than that in the shaoyin meridian (P<0.05), but there was no significant difference between the taiyin meridian and shaoyin meridian (P>0.05). There was a negative correlation between microcirculation perfusion and position (P<0.001), indicating the closer to the elbow, the more the microcirculation perfusion decreased. CONCLUSION: During arrhythmia in rabbits, the dysfunction of qi and blood existes in the three yin-meridians of hand in the forearm, particularly the jueyin meridian. In addition, the closer to the elbow, the more obvious the reaction of the three yin-meridians of hand is.

The Effect of Ex Situ Perfusion in a Swine Limb Vascularized Composite Tissue Allograft on Survival up to 24 Hours.

PURPOSE: To test the potential for the ex situ limb perfusion system to prolong limb allograft survival up to 24 hours. METHODS: We used 20 swine for the study. In group 1 (control), 4 limbs were perfused with heparin solution and preserved at 4°C for 6 hours. In group 2, 4 limbs were perfused with autologous blood at 27°C to 32°C for 24 hours. In both groups, limbs were transplanted orthotopically to recipients and monitored for 12 hours. In addition to perfusion parameters, we recorded perfusate gases and electrolytes (pH, pCO2, pO2, O2 saturation, Na, K, Cl, Ca, HCO3, glucose, and lactate) and obtained functional electrostimulation hourly throughout the experiment. Histology samples were obtained for TUNEL staining and single-muscle fiber contractility testing. RESULTS: In both groups, hemodynamic variables of circulation remained stable throughout the experiment. Neuromuscular electrical stimulation remained intact until the end of reperfusion in group 2 vs no response in group 1. In group 2, a gradual increase in lactate levels during pump perfusion returned to normal after transplantation. Compared with the contralateral limb in group 2, single-muscle fiber contractility testing showed no significant difference at the end of the experiment. CONCLUSIONS: We demonstrated extended limb survival up to 24 hours using normothermic pulsatile perfusion and autologous blood. CLINICAL RELEVANCE: Successful prolongation of limb survival using ex situ perfusion methods provides with more time for revascularization of an extremity.

[Anatomic structure of "Shaoze" (SI 1), "Qiangu" (SI 2), "Houxi" (SI 3), "Yanggu" (SI 5) and Xiaohai" (SI 8) regions of Hand-Taiyang Meridian in the rabbit's forelimb].

OBJECTIVE: To observe the anatomic structure of the Five Shu-acupoints: "Shaoze" (SI 1) ,"Qiangu" (SI 2), "Houxi" (SI 3),"Yanggu" (SI 5) and "Xiaohai" (SI 8) regions of the Taiyang Meridian in the rabbit's forelimb. METHODS: Thirty rabbits (half male and half female) were used in the present study. The Five Shu-acupoints regions were located first based on the atlas of rabbits, stimulated by needling and confirmed later by using an electronic acupoint detector. Under anesthesia, the rabbit was perfused with warm normal saline via the common carotid artery and the internal jugular vein, followed by arterial perfusion of dental base acrylic resin powder(30 g), dibutylphthalate(6 mL), red couring agent liquid for denture acrylic and acetoacetate (2 mL), respectively; and venous perfusion of 30% gelatin (filtered) and black ink (filtered) and formaldehyde (8%). After fixing in 8% formaldehyde for 10 days, the rabbit's forelimb containing the aforementioned Five Shu-acupoints were carefully dissected layer by layer, followed by observing the local anatomic structure under microscope. RESULTS: The superficial layers of these acupoint regions mainly contained the basilic vein and its branches, and the superficial branch of the ulnar nerve. The deep layers chiefly comprised of the ulnar artery, the ulnar vein and their branches, and the ulnar nerve. CONCLUSION: In "Shaoze"(SI 1 ), "Qiangu" (SI 2), "Houxi" (SI 3), "Yanggu" (SI 5) and "Xiaohai" (SI 8) acupoint regions, the ulnar artery, basilic vein, ulnar vein and their branches, the ulnar nerve and its superficial branches are found, which constitute the morphological basis of the five acupoints of the Hand-Taiyang Meridian for treating some related clinical disorders.

Evaluation of a porcine whole-limb heterotopic autotransplantation model.

BACKGROUND: Recently performed vascularized composite tissue allotransplantations (CTAs) stimulate the ongoing research in the area of whole-limb transplantation. A reliable in vivo animal model is required for investigations in vascularized whole-limb CTA. The model should allow in vivo assessment in whole-limb preservation, allograft and xenograft response, and host immunomodulation. The goal of this study is to describe and evaluate the in vivo feasibility and reproducibility of a whole-limb porcine model as a basis for future research in this field. MATERIALS AND METHODS: In seven large white pigs, one forelimb was amputated under anesthesia and autotransplanted heterotopically with an arc of rotation of 180° and partially placed in a subcutaneous pocket. Clinical parameters were monitored and muscle biopsies were analyzed using ultrastructural morphological assessment of mitochondria quality after an observation period of 7 days. RESULTS: All animals could fully mobilize postoperatively without restrictions. At sacrifice, the anastomosed pedicle vessels of the limb were patent in six animals. In one pig, venous thrombosis could be observed. Muscle response was triggered following direct electrostimulation in six replanted limbs. The replanted extremities gained 12.97% weight within 7 days postreplantation compared with the amputation baseline values (P = 0.464 while maintaining normal compartment pressures at sacrifice (8.25 ± 5.31 cmH(2)O, P = 0.60). The ultrastructural evaluation of mitochondria morphology revealed intact mitochondria without signs of ischemia/reperfusion damage. CONCLUSION: This porcine model proved feasible, reliable, and reproducible for whole-limb autotransplantation. It presents significant potential in future preclinical research of whole-limb CTA transplantation.

Black walnut extract-induced laminitis in horses is associated with heterogeneous dysfunction of the laminar microvasculature.

REASONS FOR PERFORMING STUDY: Equine laminitis purportedly involves haemodynamic dysfunction at the level of the laminar vasculature. However, to date, no studies have been performed characterising the function of laminar arteries and veins during the prodromal stages of equine laminitis. HYPOTHESIS: That the prodromal stages of laminitis are associated with contractile dysfunction of the equine laminar vasculature. OBJECTIVE: To assess contractile function of laminar arteries and veins to phenylephrine (PE) and 5-hydroxytryptamine (5-HT). METHODS: Horses were administered black walnut heartwood extract (BWHE) or water (control horses) via nasogastric intubation. After euthanasia, laminar vessels (100-800 microm internal diameter) were isolated and mounted on small vessel myographs to assess contractile function. RESULTS: Contractile responses to PE or 5-HT were identical in laminar arteries isolated from either control horses or those administered BWHE. In contrast, responses to PE or 5-HT were significantly reduced in laminar veins isolated from BWHE-administered horses when compared with laminar veins isolated from control horses. CONCLUSIONS AND POTENTIAL RELEVANCE: These results are consistent with the prodromal stages of laminitis being associated with selective dysfunction of laminar veins. Further studies are required to discern the precise nature of this dysfunction and its potential relevance to the pathogenesis of acute laminitis in the horse and possible therapeutic targets for treatment.

Effect of electrical stimulation of the mamillary nuclei of the hypothalamus on skin vessel permeability in intact and capsaicin-treated rats.

Stimulation of the mamillary nuclei of the rat hypothalamus induced increases in the permeability of forelimb skin microvessels. This effect was not seen in rats stimulated after administration of capsaicin at a dose (150 mg/kg) sufficient to deplete vasoactive neuropeptides from the peripheral nerve terminals of capsaicin-sensitive neurons. These data indicate a role for the mamillary nuclei in central mechanisms modulating the effector functions of primary capsaicin-sensitive neurons.

An assessment of the peripheral antinociceptive potential of remoxipride, clonidine and fentanyl in sheep using the forelimb tourniquet.

A modification of the intravenous regional anaesthesia technique was used to assess the peripheral antinociceptive effect of remoxipride, clonidine and fentanyl. Drugs administered intravenously via peripheral catheters were restricted to the distal limb and nociceptive threshold test site by prior inflation of a tourniquet proximal to both the catheter and a threshold-testing device. Lignocaine (1 mg/kg) induced peripheral antinociception during tourniquet inflation. Clonidine (6 micrograms/kg) only induced significant elevations in thresholds after tourniquet deflation. A low dose of remoxipride (2 mg/kg), which had no systemic antinociceptive effect, produced antinociception after its restriction to the periphery. Peripheral administration of saline and tourniquet-induced restriction of blood flow to the distal limb did not alter threshold values. Peripheral administration of fentanyl was used to test a further modification of the injection protocol designed to reduce the incidence of leakage into the systemic circulation. Fentanyl administration (11.2 micrograms/kg) failed to elicit an increase in thresholds when it was restricted to the distal limb test site. The contribution of a peripheral mechanism to the antinociception induced by systemic administration of a higher remoxipride dose (7.5 mg/kg) was investigated using an inflated tourniquet to exclude remoxipride from the periphery. Exclusion of remoxipride from the periphery reduced its antinociceptive effect, i.e. threshold values were lower than if remoxipride was allowed free access to the limb prior to tourniquet inflation. The technique described here was effective in demonstrating that the increase in noninflammatory nociceptive thresholds seen with clonidine and fentanyl is not peripherally mediated whilst that seen with remoxipride has a peripheral component.

Effect of an aqueous extract of black walnut (Juglans nigra) on isolated equine digital vessels.

An aqueous extract was made from black walnut (Juglans nigra) heartwood obtained in the fall of the year. Ten hours after nasogastric administration of 5 L of the extract, a 550-kg, 13-yr-old Quarter Horse gelding experienced Obel grade-3 laminitis. The effect of aqueous extract of black walnut on vascular contractility was then tested, using isolated equine digital arteries and veins. The vessels were maintained in Krebs bicarbonate buffer with 95% oxygen at 37 C. The extract did not induce a direct contractile effect. It did, however, reversibly enhance the vasoconstriction induced in the isolated vessels by administration of epinephrine potentiated with hydrocortisone. In contrast, aqueous extracts made, using the same techniques, from the shavings of eastern white pine (Pinus strobus), eastern red cedar (Juniperus virginiana), and pin oak (Quercus palustrus) had no effect on epinephrine-induced digital vessel contractions.

Forelimb blood flow distribution during hypothalamic dilator response.

An attempt is made to determine whether hypothalamically induced forelimb vascular dilation in the dog affects primarily exchange beds or shunt circuits. Slug injections of [131I] albumin and 86RbCl were used to measure the active vascular volume of the forelimbs and permeability surface area product (PS), respectively. Changes in total vascular volume (TVV), filtration, and capillary filtration coefficient (CFD) were measured by plethysmography. During stimulation, forelimb blood flow increased 25% and TVV increased an average 1.5 ml. There was no plethysmographic evidence of outward capillary filtration. Active vascular volume decreased 11%. PS decreased 11%, and CFC decreased 20%. These results point to a redistribution of blood flow from exchange circuits to faster flow channels. During constant-inflow perfusion, there was evidence from CFC and PS measurements that the capillary surface area was increased while active vascular volume decreased. The results observed with hypothalamic stimulation are different from those obtained with pharmacologic dilators and denervation. It is suggested that the former method has a more selective effect in lowering resistance in the faster shuntlike vessels.

Hypothalamic and brachial nerve effects on circulation of isolated canine forelimb,.

Canine forelimbs were vascularly isolated and perfused at either constant inflow or constant inflow pressure. A comparison of the effects of electrical stimulation of hypothalamic pressor areas and brachial nerves was made on several vascular parameters. During constant pressure perfusion, forelimb resistance increased and total forelimb volume decreased. Additionally active vascular volumes measured with 131I-labeled albumin and 51Cr-labeled red cells decreased significantly. Capillary diffusion capacity product calculated from extraction of 86RbCl also decreased significantly as did the capillary filtration coefficient (CFC). The only significant differences between hypothalamic and brachial nerve stimulation were noted in the larger decreases in active volumes and CFC during the latter stimulations.