新生儿肺出血29例临床病理分析

1962～1986年25年间,经尸检病理确诊的29例新生儿肺出血,以早产儿和低出生体重儿为主,生后一周内发病者27例。本组20例有窒息史,口鼻有血性分泌物流出者17例。本文描述了新生儿肺出血的临床表现和病理特征,以及对新生儿肺出血的病因作了讨论。     

Safety pharmacology of the respiratory system: Techniques and study design

The known effects of drugs from a variety of pharmacologic/therapeutic classes on the respiratory system and worldwide regulatory requirements support the need for conducting respiratory evaluations in safety pharmacology. The objective of these studies is to evaluate the potential for drugs to cause secondary pharmacologic or toxicologic effects that influence respiratory function. Changes in respiratory function can result either from alterations in the pumping apparatus that controls the pattern of pulmonary ventilation or from changes in the mechanical properties of the lung that determine the transpulmonary pressures (work) required for lung inflation and deflation. Defects in the pumping apparatus are classified as hypo- or hyperventilation syndromes and are evaluated by examining ventilatory parameters in a conscious animal model. The ventilatory parameters include respiratory rate, tidal volume, minute volume, peak (or mean) inspiratory flow, peak (or mean) expiratory flow, and fractional inspiratory time. Defects in mechanical properties of the lung are classified as obstructive or restrictive disorders and can be evaluated in animal models by performing flow-volume and pressure-volume maneuvers, respectively. The parameters used to detect airway obstruction include peak expiratory flow, forced expiratory flow at 25 and 75% of forced vital capacity, and a timed forced expiratory volume, while the parameters used to detect lung restriction include total lung capacity, inspiratory capacity, functional residual capacity, and compliance. Measurement of dynamic lung resistance and compliance, obtained continuously during tidal breathing, is an alternative method for evaluating obstructive and restrictive disorders, respectively, and is used when the response to drug treatment is expected to be immediate (within minutes post-dose). The species used in the safety pharmacology studies conducted in our laboratory are the same as those used in toxicology studies since pharmacokinetic and toxicologic/pathologic data are available in these species. These data can be used to help select test measurement intervals and doses and to aid in the interpretation of functional change. The techniques and procedures for measuring respiratory function parameters are well established in guinea pigs, rats, and dogs.     

THE EFFECT OF HYPERTENSIVE EPISODES AND CARDIAC HYPERTROPHY ON THE CANINE CARDIAC BAROREFLEX

1. Left ventricular (LV) hypertrophy has been implicated in the reduction of baroreflex sensitivity present in hypertension. The aim of the current study was to investigate the mean arterial pressure-heart rate reflex (MAP-HR) in a model which induced left ventricular hypertrophy but no sustained blood pressure elevation. 2. Five mongrel dogs were exposed to transient blood pressure elevation of between 20 and 30 mmHg, through hindlimb compression using a pneumatic pressure suit, for 7 h per day, 6 days per week for 6 weeks. Resting blood pressure was not altered by the 6 week hindlimb compression intervention. 3. Echocardiographically determined LV mass (mean ± s.e.m.) was 116.0 ± 7.4 g prior to hindlimb compression (baseline) and elevated to 125.4 ± 8.1 g (P= 0.003) after 6 weeks of compression. A reduction in the early (E) to late (A) transmitral diastolic flow ratio (E/A) from 1.80 ± 0.06 at baseline to 1.54 ± 0.09 (P = 0.037) after the 6 week intervention suggested that cardiac compliance was reduced. 4. The maximum gain of the MAP-HR reflex, studied using the ‘steady-state’ drug technique, when blood pressure was normal, showed a trend for reduction from 3.85 ± 0.43 beats/min per mmHg at baseline to 3.10 ± 0.45 beats/min per mmHg (P= 0.067) after 6 weeks of compression. This gain reduction became significant after β-adrenoceptor blockade with propranolol (3.13 ± 0.55 vs 2.32 ± 0.25 beats/min per mmHg; P= 0.039). Covariant analysis showed a significant inverse correlation between LV mass and maximum gain (r= 0.96; P<0.001) during the 6 week compression period. 5. The MAP-HR reflex changes in this model mimic those present in hypertension and implicate cardiac hypertrophy as one possible mediator.     

RENIN GENE POLYMORPHISM ASSOCIATED WITH ALDOSTERONE RESPONSIVENESS TO THE RENINANGIOTENSIN SYSTEM IN PATIENTS WITH ALDOSTERONE-PRODUCING ADENOMAS

1. Aldosterone levels in patients with unilateral aldosterone-producing adenomas may be responsive or unresponsive to the renin-angiotensin system, with the former often previously misdiagnosed as bilateral adrenal hyperplasia. 2. In tumours from patients in the responsive subgroup, renin mRNA is expressed in greater amounts than in tumours from patients in the unresponsive subgroup, or in normal adrenals. 3. We compared the frequency of four renin gene polymorphisms in peripheral blood DNA from the two subgroups and found significant associations between BglI, TaqI and HinfI restriction fragment length polymorphisms (RFLP) and aldosterone responsiveness. 4. Allelic variation in the constitutive renin gene was associated with a specific cause of hypertension.     

VASOCONSTRICTOR RESPONSES TO COMPONENTS OF THE RENIN-ANGIOTENSIN SYSTEM IN CYCLOSPORIN-INDUCED HYPERTENSION IN THE RAT

1. Since plasma renin activity is increased in cyclosporin A (CsA)-induced hypertension in the rat, the role of the vascular renin-angiotensin system (RAS) in CsA-induced hypertension was investigated in rat mesenteric resistance vessels. 2. Female Wistar rats received CsA (10 mg/kg per day, s.c.) or vehicle for 30 days. CsA treatment increased tail-cuff systolic blood pressure (CsA treated 135 ± 3 mmHg vs control 125 ± 1 mmHg, P<0.0001). 3. Mesenteric resistance arteries (200–300 μm) were isolated and mounted in a microvessel myograph. Concentration-response curves to tetradecapeptide renin substrate (10-¹¹-10^?6 mol/L), angiotensin I (10-^l1-10^?6 mol/L) and angiotensin II (10-¹²-10^?6 mol/L) showed no differences between CsA-treated and control groups. 4. Mesenteric vascular angiotensin-converting enzyme (ACE) characteristics were determined by radioligand binding. There were no differences in the content or affinity of ACE between CsA-treated and control rats. 5. These results suggest that the mesenteric vascular RAS does not play a major role in CsA-induced hypertension in the rat.     

硝基胍的毒性研究

目的对硝基胍的毒性进行研究,为制订卫生标准提供依据.方法包括急性毒性试验、蓄积毒性试验及亚慢性毒性试验.结果硝基胍大鼠经口LD50为8 066 mg/kg,小鼠经口LD50为10 044 mg/kg,蓄积系数大于5.3.亚慢性毒性试验中,高剂量组雄性大鼠在染毒第3周和第8周,体重有明显的负增长(P＜0.05);高剂量组雄性大鼠睾丸脏器系数明显高于对照组(P＜0.05);红细胞免疫功能测定结果显示,中、高剂量组大鼠红细胞受体花环率分别为10.00±2.37和7.50±2.66,明显低于对照组(P＜0.05,P＜0.01).其余各项指标未见明显改变.结论硝基胍属于微毒级毒物,轻度蓄积,亚慢性毒性试验对动物有一定的影响.     

Oxidative stress: does it play a role in the genesis of essential hypertension and hypertension of uraemia?

Reactive oxygen species: general aspects Reactive oxygen species, including superoxide radicals, hydrogenperoxide, nitric oxide, peroxynitrite, hydroxyl radicals andhypochlorous acid are by-products of normal metabolic processesin cells. Reactive oxygen species can be found in several cellsincluding macrophages and vascular smooth muscle cells. At lowconcentrations reactive oxygen species can act as physiologicalmediators of cellular responses whereas higher concentrationsmay cause cell damage [1,2]. The major sources of reactive oxygenspecies are leakages from the electron transport chains of mitochondriaand endoplasmic reticulum. Cellular energy metabolism is basedon the production of ATP through the electron transport reactionin which O₂ accepts electrons and H⁺ and then is eventuallyreduced to water. Only 1–2% of the electrons are leakedto generate superoxide radicals in reactions mediated by coenzymeQ and ubiquinone and its complexes. During ageing (and probablyin patients     

ENDOSCOPIC PANCREATIC STENTING IN CHRONIC PANCREATITIS WITH DUCTAL DILATION PROXIMAL TO A STRICTURE: A SAFE and EFFECTIVE PROTOCOL

After removal of intraductal stones, a 10‐Fr or 7‐Fr pancreatic stent was placed in 16 patients with upstream ductal dilation proximal to a stricture of the main pancreatic duct. Stents were removed after a mean duration of 52.5 days. Nine patients underwent repeated stenting. About one year after removal of the initial stent, when the remaining upstream ductal dilation was found on follow‐up pancreatograms, the next stent was replaced. Repeated stenting improved outflow of pancreatic juice more effectively than one‐time stenting. Correlation between long‐term pain relief without recurrence of intraductal stones and reduction of duct diameter was also shown. Stent occlusion was observed in 14 of 30 stents. Stent occlusion was frequently associated with recurrence of pancreatitis and intraductal stones, and was also associated with morphologic changes in the pancreatic ductal system. Although there were no significant differences between stent patency of the initial stents and that of the next stents, stent patency of 10‐Fr stents was superior to that of 7‐Fr stents. 10‐Fr stents should be removed within 8 weeks and 7‐Fr stents should be removed within 4 weeks for the prevention of stent occlusion. Repeated stenting with short‐term stenting is therefore considered a safe and effective protocol of endoscopic pancreatic stenting.     

WHO and ATPIII proposals for the definition of the metabolic syndrome in patients with Type 2 diabetes.

AIMS: Different criteria have been proposed by the World Health Organization (WHO) and by the Third Report of the National Cholesterol Education Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (ATPIII) for the diagnosis of the metabolic syndrome. Its identification is of particular importance for coronary risk assessment. METHODS: The prevalence of the metabolic syndrome was determined according to the two different proposals in 1569 consecutive subjects with Type 2 diabetes. RESULTS: By the WHO proposal, 81% of cases (95% confidence interval, 79-83) were labelled as metabolic syndrome. Microalbuminuria had the highest specificity (99%) and visceral obesity the highest sensitivity (93%). Seventy-eight per cent of patients (95% CI, 76-80) fulfilled the ATPIII criteria for metabolic syndrome, low HDL-cholesterol having the highest specificity (95%), elevated blood pressure having the highest sensitivity. According to both proposals, 1113 patients were positive; 183 were concordantly negative, indicative of a fairly good agreement (k statistics, 0.464). Subjects only positive for the WHO proposal were more frequently males, had a lower BMI and a higher arterial pressure. Only subjects identified by the ATPIII proposal had a significantly higher prevalence of previously detected coronary heart disease. CONCLUSIONS: Minimum criteria for the metabolic syndrome are met in most patients with Type 2 diabetes. Correct identification of the syndrome is important for an integrated approach to reduce the high costs and the associated disabilities. The ATPIII proposal more clearly identifies the burden of coronary heart disease associated with the metabolic syndrome.