硝酸甘油对高危妊娠胎儿—胎盘血流动力学的影响

应用Acuson-128彩色电脑声像仪监测12例高危妊娠孕妇应用硝酸甘油前后的脐动脉、胎儿大脑中动脉,胎儿腹主动脉的血流动力学变化。结果:用药后脐动脉的搏动指数(PI),阻力指数(RI)和S/D值均显著降低(P<0.001),胎儿大脑中动脉和胎儿腹主动脉的PI、RI和S/D值无显著改变,呈现良好的耐受性,表明应用硝酸甘油可明显降低脐-胎盘血管阻力,是改善胎儿血氧供应的简便、有效方法,并对硝酸甘油的作用机理进行了讨论。     

Anal fissure: the changing management of a surgical condition

Background Chronic anal fissure is a common benign disorder that causes severe, sharp anal pain during defaecation. Fissures are generally associated with raised resting anal pressures, and treatments are aimed at reduction of these pressures. Surgical sphincterotomy is very successful at healing fissures but is associated with significant morbidity. Much work has gone into the development of new pharmacological agents that can promote healing of chronic anal fissures by production of a reversible chemical sphincterotomy, with the aim of avoiding long-term problems of incontinence.Methods We review these recent innovations that have largely replaced surgery as first line treatment for chronic anal fissure.Conclusions Despite there being initial success with many of these pharmacological agents in the treatment of patients with chronic anal fissures, there are still some concerns about their use. In particular, the occurrence of side effects limits their use, and, unfortunately, they are not always effective at healing fissures. However, despite these drawbacks they remain excellent first-line options in the treatment of chronic anal fissures, and surgery should be offered only to patients who fail these therapies.     

RENAL, ADRENAL AND VASCULAR CHANGES DURING INHIBITION OF CONVERTING ENZYME WITH CAPTOPRIL

1. In rats treated continuously with captopril (80 μg/h, i.p.), for 2 days, blood pressure decreased and adrenal angiotensin II receptor concentration was decreased from 160 fmol/mg protein (s.e.m.=9) in controls to 131 fmol/mg protein (s.e.m. = 7, P < 0.01, n= 10). However, after 5 days of continuous treatment, blood pressure had returned to normal and adrenal receptor concentrations in treated rats were not significantly different from controls (180 fmol/mg, s.e.m. = 11 and 203 fmol/mg protein s.e.m. = 14 respectively, 0.1>P>005). 2. Vascular reactivity, defined as the pressor response to exogenous angiotensin II, increased concurrently by 166 and 33% respectively. 3. In anaesthetized dogs (n= 8), captopril (1.5 mg/kg, i.v.) caused a fall in blood pressure, and urine bradykinin excretion increased from 1 08 (s.e.m.=0 14) to 1 64 μg/h (s.e.m.=0 33, P < 0 025) at 15 min. Renal blood flow increased significantly (P < 0 01) with no change in glomerular filtration rate, and there was no change in either renal venous or arterial blood bradykinin levels. 4. Thus, converting enzyme inhibition produces transient secondary changes in angiotensin receptors and vascular reactivity. Increased urine bradykinin probably reflects decreased catabolism of intrarenal bradykinin. The hypotensive effect of captopril may be due in part to raised levels of bradykinin in the kidney.     

Folic acid improves endothelial function in children and adolescents with type 1 diabetes

OBJECTIVE: To evaluate the effect of folate supplementation on endothelial function in children and adolescents with type 1 diabetes. STUDY DESIGN: Thirty-six subjects with type 1 diabetes age 13.6+/-2.6 years completed a randomized, double-blind, placebo-controlled crossover trial. Each subject received 8 weeks of oral folic acid (5 mg/d) and 8 weeks of placebo, with an 8-week washout period. Before and after each intervention, we assessed endothelial function by using brachial artery responses to flow (flow-mediated dilatation [FMD]) and glyceryl trinitrate, von Willebrand factor, glucose, hemoglobin A1c, total plasma homocyst(e)ine (tHcy), vitamin B(12), serum folate, and red cell folate (RCF). RESULTS: Folic acid increased FMD by 2.58 (3.1-5.7) % (95% confidence interval, 1.28-3.88), whereas placebo did not change FMD (-0.42%; 95% confidence interval, -1.67 to 0.83; P<.001). Folic acid increased serum folate by 14 nmol/L (6.2 ng/mL, P<.001) and RCF by 467.2 nmol/L (206 ng/mL, P<.001). Change in FMD was related to change in serum folate (r=0.46, P=.005) and RCF (r=0.39, P=.02). Glyceryl trinitrate responses, von Willebrand factor, tHcy, and hemoglobin A1c were not affected by the intervention. CONCLUSIONS: Short-term high-dose folic acid improves endothelial function in children and adolescents with type 1 diabetes and normal folate status independently of tHcy.     

The nitric oxide donor glyceryl trinitrate increases subchondral bone sclerosis and cartilage degeneration following ovine meniscectomy

AIM: To examine the effect of glyceryl trinitrate (GTN), a nitric oxide (NO) donor compound, on the concurrent progression of cartilage and subchondral bone changes in an ovine meniscectomy model of osteoarthritis (OA). METHODS: Bilateral lateral meniscectomy (MX) was performed on 12 ewes to induce OA. Six were treated with topical GTN (0.7mg/kg twice weekly) (MX+GTN). Six other sheep formed non-operated controls (NOC). After sacrifice at six months, the subchondral bone density (BMD) of the lateral and medial femoral condyles (LFC, MFC) and tibial plateau (LTP, MTP) was assessed by DEXA. Dynamic biomechanical testing was performed across the MTP and LTP. Histological sections from each region were scored qualitatively and the thickness of the subchondral bone plate (SCB) was determined by image analysis. RESULTS: MX+GTN displayed significantly greater SCB thickness relative to MX in the LFC (mean increase +88% and +42%, respectively) and the MFC. SCB BMD was 10-12% greater in MX+GTN relative to MX in the LFC, LTP and MTP. MX+GTN sheep also showed greater increases in some histopathology variables, greater central erosion of the LTP, and changes in dynamic stiffness (decreased) and phase lag (increased) in the outer zone of the LTP. CONCLUSIONS: Treatment with GTN significantly increased subchondral bone thickness and density during subchondral remodelling following meniscectomy. In addition, it slightly but significantly worsened degeneration of cartilage structure and function. These results suggest that clinical use of GTN may accelerate both cartilage degeneration and subchondral bone sclerosis if used in the presence of OA, and demonstrate that NO has the potential be an important mediator of the subchondral bone changes seen in OA.     

Nitric oxide potentiates response of trigeminal neurones to dural or facial stimulation in the rat

Infusing glyceryl trinitrate as a donor molecule, we have used electrophysiological and c-fos immunostaining techniques to study the effects of nitric oxide on neurones in the nucleus trigeminalis caudalis. Following infusion of glyceryl trinitrate, responses of neurones to electrical stimulation of periorbital cutaneous afferents were potentiated and threshold for activation of neurones by stimulation of dural afferents was reduced. Expression of c-fos was unchanged by glyceryl trinitrate compared to saline controls. Intradermal injection of capsaicin in the periorbital area increased c-fos expression in nucleus trigeminalis caudalis; this was significantly potentiated by glyceryl trinitrate. These results suggest that, in the anaesthetized rat, glyceryl trinitrate alone may not acutely activate the trigeminovascular system to a significant degree at doses that cause headache and later trigger migraine headache in migraineurs. Nevertheless, it is susceptible to exogenous nitric oxide in that activation of trigeminal neurones through cutaneous or dural pathways is potentiated. This may in some measure underlie the pathogenesis of migraine headache.     

Treatment of anal fissure with glyceryl trinitrate in patients referred for surgical management

Background : A number of recent studies indicate that anal fissure may be treated by applying glyceryl trinitrate (GTN) ointment. The present study aims to determine the effectiveness and patient acceptability of GTN treatment for patients referred to a consultant surgeon. Methods : A prospective study of 65 consecutive patients referred to one surgeon (ALP) over a 12‐month period was undertaken. All patients were offered 0.2% GTN ointment to be applied intra‐anally four times daily for 4 weeks. Informed consent was obtained and review planned for 4 weeks. Results : Fourteen patients declined treatment and nine of the 14 (64%) subsequently underwent lateral sphincterotomy. Twelve of the 51 patients (18.5%) who accepted treatment could not complete it due to headache or persisting severe anal pain. Thirty‐nine of the 51 patients (77%) were able to complete 4 weeks of treatment. Twenty‐two of the 39 reported an improvement in symptoms. A total of 22 patients (43%) who started GTN treatment subsequently underwent lateral sphincterotomy. Conclusions : Evidence from the present study suggests that GTN ointment has a place in the management of referred patients with severe and/or chronic anal fissure, but sphincterotomy remains an important treatment option for the majority.     

RENAL VENOUS WEDGE PRESSURE IN RENAL WRAP HYPERTENSION IN RABBITS

1. Renal cellophane wrapping to produce hypertension causes thickening of the capsule of the kidney. To determine whether this compresses the kidney, deep renal vein wedge pressure was measured as an estimate of tissue pressure in anaesthetized rabbits 1 month after cellophane wrapping (n= 5) or a sham operation (n= 3). 2. Renal vein wedge pressure was 18.3 ± 2.0 mmHg in hypertensive rabbits and 8.4 ± 1.1 mmHg in the sham-operated rabbits. 3. Arterial pressure was raised or lowered with angiotensin II or glyceryl trinitrate, respectively. Arterial and wedge pressures were approximately linearly related and, at any given arterial pressure, wedge pressure was approximately 8 mmHg higher in the cellophane-wrapped kidney than in the kidney of the sham-operated group. 4. These results, showing that renal wedge pressure is elevated in renal wrap rabbits, indicate that the kidneys are compressed, probably by the thickened renal capsule. This may explain the increased renal vascular resistance seen in this form of hypertension.     

Comparison of topically applied 0.2% glyceryl trinitrate ointment, incision and excision in the treatment of perianal thrombosis

BACKGROUND AND AIMS: Topically applied 0.2% glyceryl trinitrate ointment to the anal region, incision and excision were compared in the treatment of perianal thrombosis, in order to establish which method is the best in terms of pain relief, number of recurrences and the appearance of anal skin tags. PATIENTS AND METHODS: A total of 150 patients were randomly divided into three groups of 50, each group being treated by one of the above-mentioned methods. The results of the treatment were evaluated during the first 4 days, after one month and after one year. RESULTS: A statistically significant reduction of pain was achieved by excision if compared with incision or conservative treatment with glyceryl trinitrate (p<0.001), and by conservative treatment with glyceryl trinitrate if compared with incision (p<0.01 on the 4th day of follow-up. Comparison of patients treated by the three different methods did not reveal any significant difference between these methods after one month (p>0.05). After one year the number of recurrences was significantly reduced after excision if compared with incision (p<0.05) or conservative treatment with glyceryl trinitrate (p<0.05). The number of patients without symptoms was significantly greater after excision if compared with incision or conservative treatment with glyceryl trinitrate (p<0.001). The number of patients with anal skin tags was significantly reduced in patients treated by excision if compared with incision (p<0.001) or glyceryl trinitrate treatment (p<0.001). CONCLUSION: Excision is a significantly better method of treatment of perianal thrombosis than incision or topically applied 0.2% glyceryl trinitrate ointment.     

Prevention and management of recurrent postoperative Hirschsprung's disease obstructive symptoms and enterocolitis: Systematic review and meta-analysis

Background/Purpose

The purpose of this study was to review the management of obstructive symptoms and enterocolitis (HAEC) following pull-through for Hirschsprung's disease.