[Afferent baroreflex failure with hyponatremia: A case report].

Afferent baroreflex failure (ABF) is a rare disease. It refers to the clinical syndrome caused by the impairment of the afferent limb of the baroreflex or its central connections at the level of the medulla. The recognized causes include trauma, surgery in related areas (radical neck tumor surgery, carotid endarterectomy), neck radiotherapy, brain stem stroke, tumor growth paraganglioma and hereditary diseases, among which the most common cause is extensive neck surgery or radiotherapy for neck cancer. The main manifestations are fluctuating hypertension, orthostatic hypotension, paroxysmal tachycardia and bradycardia. This case is a young man, whose main feature is blood pressure fluctuation, accom-panied by neurogenic orthostatic hypotension (nOH). After examination, the common causes of hypertension and nOH were ruled out. Combined with the previous neck radiotherapy and neck lymph node dissection, it was considered that the blood pressure regulation was abnormal due to the damage of carotid sinus baroreceptor after radiotherapy for nasopharyngeal carcinoma and neck lymph node dissection, which was called ABF. At the same time, the patient was complicated with chronic hyponatremia. Combined with clinical and laboratory examination, the final consideration was caused by syndrome of in- appropriate antidiuretic hormone (SIADH). Baroreceptors controlled the secretion of heart rate, blood pressure and antidiuretic hormone through the mandatory "inhibition" signal. We speculate that the carotid sinus baroreceptor was damaged after neck radiotherapy and surgery, which leads to abnormal blood pressure regulation and nOH, while the function of inhibiting ADH secretion was weakened, resulting in higher ADH than normal level and mild hyponatremia. The goal of treating ABF patients was to reduce the frequency and amplitude of sudden changes in blood pressure and heart rate, and to alleviate the onset of symptomatic hypotension. At present, drug treatment is still controversial, and non-drug treatment may alleviate some patients' symptoms, but long-term effective treatment still needs further study. The incidence of ABF is not high, but it may lead to serious cardiovascular and cerebrovascular events, and the mechanism involved is extremely complicated, and there are few related studies. The reports of relevant medical records warn that patients undergoing neck radiotherapy or surgery should minimize the da-mage to the baroreceptor in the carotid sinus in order to reduce the adverse prognosis caused by complications.

Effect of hirudin on arterialized venous flap survival in rabbits.

Arterialized venous flap (AVF) is limited in clinical application because its survival remains inconsistent and its exact survival mechanism is still unclear. Hirudin is an effective thrombin specific inhibitor, which is isolated from the salivary gland secretions of the leech. Our study evaluated the impact of hirudin on the viability of AVFs in rabbits. Thirty-six rabbits were randomly divided into three groups: sham group (physiological perfusion), control group (AVF), and hirudin group (AVF + hirudin). In hirudin group, 20 antithrombin units (ATU) hirudin (2.5 ml) were injected into each flap. In sham group and control group, the same amount of normal saline was injected into each flap. Status of flap survival, water content, vascular perfusion, histopathology, expression of CD34, VEGF, eNOS and HIF-1α were analyzed in each group. Analysis of oxidative stress was performed by measuring the activity of superoxide dismutase (SOD) and malondialdehyde (MDA). Compared with flaps in sham group with physiological perfusion mode, results of survival rate, perfusion status, SOD activity, expression of CD34, VEGF, and eNOS of AVFs in control group were significantly lower, while water content, MDA level and expression of HIF-1α were higher. The flap condition of AVFs injected with hirudin in hirudin group was improved significantly, and the results were similar to sham group. Our findings revealed that hirudin can effectively improve survival of AVF.

Trans-Cinnamaldehyde Increases Random Pattern Flap Survival Through Activation of the Nitric Oxide Pathway.

BACKGROUND: The application of random pattern skin flaps is limited in plastic surgery reconstruction due to necrosis. Trans-cinnamaldehyde has antibacterial, anticancer, and antioxidant properties. In this study, we aimed to investigate the effect of trans-cinnamaldehyde on skin flap survival and its possible mechanism regarding nitric oxide. MATERIALS AND METHODS: One hundred forty male Sprague-Dawley rats were randomly divided into seven groups (n = 20 each group). After the dorsal flap was raised, different doses of trans-cinnamaldehyde (10, 20, and 30 mg/kg) were immediately given by oral gavage in the three different groups. To assess the possible involvement of the nitric oxide system, NG-nitro-L-arginine methyl ester (L-NAME, a nonselective nitric oxide synthase inhibitor) was used in this study. All flap samples were incised on postoperative day 7. RESULTS: Our results showed that flap survival was increased significantly in the 20 mg/kg (P < 0.001) trans-cinnamaldehyde (TC) group compared to the control group or 30 mg/kg TC group. This protective function was restrained by coadministration of L-NAME with 20 mg/kg TC. The results of histopathology, laser Doppler, arteriography mediated with oxide-gelatine, and fluorescent staining all showed a significant increase in capillary count, collagen deposition, angiogenesis, and flap perfusion. Immunohistochemistry results revealed a significant increase in the expression of CD34, eNOS, and VEGF. CONCLUSION: Trans-cinnamaldehyde increased flap survival through the nitric oxide synthase pathway and contributed to angiogenesis. A concentration of 20 mg/kg trans-cinnamaldehyde was recommended in this study.

Gastrodin Promotes the Survival of Random-Pattern Skin Flaps via Autophagy Flux Stimulation.

The random-pattern flap has a significant application in full mouth restoration (reconstructive surgery) and plastic surgery owing to an easy operation with no axial vascular restriction. However, distal necrosis after flap operation is still considered the most common complication which makes it the Achilles heel in the clinical application of random-pattern flaps. A Chinese medicinal herb named gastrodin is an effective active ingredient of Gastrodia. Herein, the existing study explored the significant potential of gastrodin on flap survival and its underlying mechanism. Our obtained results show that gastrodin will significantly improve flap survival, reduce tissue edema, and increase blood flow. Furthermore, our studies reveal that gastrodin can promote angiogenesis and reduce the apoptotic process as well as oxidative stress. The results of immunohistochemistry and immunoblotting revealed that gastrodin has a role in the elevation of autophagy flux which results in induced autophagy. The use of 3MA (3-methyladenine) for the inhibition of induced autophagy significantly weakened the underlying benefits of gastrodin treatment. Taken together, our obtained results confirmed that gastrodin is an effective drug that can considerably promote the survival rate of flaps (random pattern) via enhancing autophagy. Enhanced autophagy is correlated with the elevation of angiogenesis, reduced level of oxidative stress, and inhibition of cell apoptosis.