Long-term effects of maternal diabetes on vascular reactivity and renal function in rat male offspring

Fetal growth impairment can occur in pregnancy complicated by diabetes. Although several studies have focused the effects of nutritional status on intrauterine development, the long-term impact of maternal diabetes on vascular and renal function in the offspring is poorly investigated. In the present study, blood pressure profiles and renal function parameters were investigated in the offspring of diabetic rats (DO). Female rats were made diabetic throughout gestation with a single dose of streptozotocyn (STZ) 10 d before mating. After weaning, the offspring had free access to food and water. Arterial pressure was evaluated every 15 d. Functional and morphometric kidney studies were performed in newborn, 3, 6 and 12-mo-old male rats in DO and in controls, C. Although maternal diabetes did not affect nephron number in the young adult rat, glomerular hypertrophy developed from 3 mo on. Glomerular Filtration Rate and Renal Plasma Flow were observed to be significantly decreased in DO when compared with C, from 3 mo on. In DO, hypertension was observed from 8 wk on and persisted elevated throughout the experimental period (12 mo). Vascular reactivity, evaluated in mesenteric arterial bed showed a decreased endothelium-dependent vasodilatation in 12-mo-old DO animals, while preserved response to sodium nitroprusside was demonstrated. Our data show that exposure to intrauterine diabetes induced by STZ does not affect nephron number in the young offspring but can cause permanent changes in Nitric Oxide (NO)-related vascular response, which, in turn may accelerate the natural age-related nephron loss.     

Maternal protein restriction suppresses the newborn renin-angiotensin system and programs adult hypertension in rats

Restriction of maternal protein intake during rat pregnancy produces offspring that are hypertensive in adulthood, but the mechanisms are not well understood. Our purpose was to determine whether this adult hypertension could be programmed during development by suppression of the fetal/newborn renin-angiotensin system (RAS) and a consequent reduction in nephron number. Pregnant rats were fed a normal protein (19%, NP) or low-protein (8.5%, LP) diet throughout gestation. Birth weight was reduced by 13% (p < 0.0005), and the kidney/body weight ratio was reduced in LP pups. Renal renin mRNA levels were significantly reduced in newborn LP pups; renal renin concentration and renin immunostaining were suppressed. Renal tissue angiotensin II levels were also suppressed in newborn LP (0.079 +/- 0.002 ng/mg, LP versus 0.146 +/- 0.016 ng/mg, NP, p < 0.01). Mean arterial pressure in conscious, chronically instrumented adult offspring (21 wk) was higher in LP (135 +/- 1 mm Hg, LP versus 126 +/- 1 mm Hg, NP, p < 0.00007), and GFR normalized to kidney weight was reduced in LP (p < 0.04). The number of glomeruli per kidney was lower in adult LP offspring (21,567 +/- 1,694, LP versus 28,917 +/- 2,342, NP, p < 0.03), and individual glomerular volume was higher (1.81 +/- 0.16 10(6) microm(3), LP versus 1.11 +/- 0.10 10(6) microm(3), NP, p < 0.005); the total volume of all glomeruli per kidney was not significantly different. Thus, perinatal protein restriction in the rat suppresses the newborn intrarenal RAS and leads to a reduced number of glomeruli, glomerular enlargement, and hypertension in the adult.     

Naturally occurring intrauterine growth retardation and adult blood pressure in rats

In humans, infants who are born small have been reported to have higher blood pressure in adulthood than do larger infants. This suggests that factors in the intrauterine environment that affect fetal growth can program the individual for hypertension later in life. The present study determined whether there is a similar, naturally occurring relationship between birth weight and adult blood pressure in rats. Female Sprague-Dawley rats bred in our colony were fed a normal diet during pregnancy. On the day of delivery, any pups that weighed <90% of the mean pup weight for the litter were identified as runts. For each runt, a sex-matched littermate of normal weight was also identified and assigned to this study. These pairs were chronically instrumented at approximately 20 wk of age. Mean arterial pressure was significantly higher in runt male and female offspring compared with their normal birth weight littermates (males: 149 +/- 7, runts versus 129 +/- 4 mmHg, controls; females: 128 +/- 1, runts versus 119 +/- 2 mmHg, controls). Although the runts had smaller body weights at study than did their littermate controls, the kidney-to-body weight ratio and renal function normalized to kidney or body weight were not different. These studies indicate that adult blood pressure is related to birth weight in rats, as it is in humans. The relative hypertension in runt animals is not due to gross differences in renal function but may be related to more subtle renal structural and/or functional differences.     

Mechanism of the unique susceptibility of deep cortical glomeruli of maturing kidneys to severe focal glomerular sclerosis

The alterations in single glomerular hemodynamics, glomerular size, and development of glomerular sclerosis after subtotal nephrectomy were assessed in approximately 32-d-old young and greater than 3-mo-old adult Munich-Wistar rats. In 6 wk, young rats developed more pronounced glomerular sclerosis and more marked elevation in blood urea nitrogen. The deep (versus superficial) cortical region of young rats was characterized by having a greater number of glomeruli with advanced sclerosis. Single nephron glomerular filtration rate of superficial glomeruli of the young increased to a much greater extent than whole kidney glomerular filtration rate, whereas there were comparable post-subtotal nephrectomy increases in whole kidney glomerular filtration rate in these two age groups, indicating that the deep glomeruli were exposed to a lesser hemodynamic load than were the superficial. Since the remnant nephrons of young and adult rats achieved equally high glomerular pressures and comparably large glomerular size shortly after subtotal nephrectomy, the unique susceptibility of young glomeruli to sclerosis is attributed to the intrinsic property of these glomeruli, rather than the abnormal hemodynamics or stimuli promoting hypertrophy and mesangial matrix accumulation imposed upon the glomeruli.     

Chronic partial ureteral obstruction in the neonatal guinea pig. I. Influence of uninephrectomy on growth and hemodynamics

Although obstructive nephropathy is a frequent cause of renal insufficiency in infancy, factors influencing adaptation to chronic partial ureteral obstruction (CPUO) are poorly understood. Guinea pigs were subjected to unilateral CPUO within the first 2 days of life (Group I) and microsphere studies were performed at 23 +/- 3 days of age. To also investigate the role of functional renal mass on growth and hemodynamics, contralateral nephrectomy was performed in Group II at the time of ureteral constriction. Compared to sham-operated controls (ureteral diameter = 1 mm) CPUO caused impaired somatic growth in both groups. Resulting hydroureteronephrosis was variable and most severe (ureteral diameter greater than 3 mm) in azotemic animals of Group II, which demonstrated reduced compensatory renal hypertrophy and poorest somatic growth. Mean arterial blood pressure was not affected by CPUO or uninephrectomy. Renal blood flow (RBF) was higher in Group II than Group I, and did not fall significantly with severity of CPUO in Group II, in which number of perfused glomeruli was similar to controls. In contrast, renal vascular resistance (RVR) increased by 172% in animals of Group I with severe CPUO, and was associated with 34% fewer perfused glomeruli than in the hypertrophied contralateral kidney. With increasing severity of CPUO, RBF tended to be distributed to outer cortical regions in the obstructed kidney of Group I, while the shift in RBF distribution was from outer to inner cortex in the remaining kidney of Group II. Filtration fraction fell as a result of CPUO in both groups, such that reduction in the glomerular filtration rate was due in large part to factors other than RBF.(ABSTRACT TRUNCATED AT 250 WORDS)     

Vitamin D deficiency, pancreatic and small intestinal enzyme development in rats

Maternal vitamin D deficiency has been shown to lead to reduced body weights in developing rat pups. To evaluate the effects of vitamin D deficiency alone both in dams and pups during the perinatal age on the ontogeny of gastrointestinal enzymes, female weanling rats (3 weeks of age) were divided into three groups. Groups I and II were fed a control (vitamin-D-replete) diet. Group II were fed a vitamin-D-deficient diet. Six weeks afterward they were mated with normal male rats while continuing on their respective diets until sacrifice. Only rats that delivered their pups on the same day from each group were brought into the study. Litter sizes of groups I and II were adjusted to 10, while group III was adjusted to 13 such that the rate of growth paralleled that of group II. At 19 days after birth, all dams and pups were sacrificed. There were no differences in the calcium and phosphorus contents in breast milk obtained from dams of each group. The serum calcium concentration of pups from group II (vitamin-D-deficient) was lower than the other groups. Body weights of pups from groups II and III were significantly lower than those of group I. The mucosal weight, total mucosal protein, mucosal DNA, sucrase, and maltase activities from groups II and III were similar, but lower than group I. Pancreatic weight, total pancreatic protein, DNA, amylase, and lipase activities from groups II and III were also similar, but lower than group I. Vitamin D deficiency was confirmed in both dams and pups from group II.(ABSTRACT TRUNCATED AT 250 WORDS)     

Congenital malformations in offspring of diabetic rats: experimental study on the influence of the diet composition and magnesium intake

In spite of improvements in the treatment of diabetes, the risk of congenital malformations in diabetic pregnancy is three to four times higher than in normal pregnancy. This might be due to the metabolic abnormalities of diabetic pregnancy that also affect mineral metabolism. Since diabetes can lower both maternal and fetal blood Mg levels, and Mg deficiency has been shown to be teratogenic in laboratory animals, we decided to investigate which effects Mg deficiency would have in inducing embryopathy in diabetic animals. Female CD rats were divided into six groups. Groups 1 and 2 were fed a standard diet (Mg content 4,200 ppm), groups 3-6 a purified diet (Mg contents 4,200, 500, 250, or 125 ppm). Groups 2-6 had been made diabetic by an intravenous injection of 50 mg/kg streptozocin 1 week before mating. The rats were killed on day 21 of pregnancy, and the live fetuses were examined for external, skeletal, and visceral malformations. The maternal and fetal blood glucose levels were the same in all diabetic groups. The maternal Mg levels in groups 2 and 3 were the same as in controls, but definitely lower in groups 4-6. Embryotoxicity (embryonic deaths, delayed development, congenital malformations) was higher in the groups fed the purified diet than in group 2, but without a clear relation to the dietary Mg levels. We cannot draw any conclusions about the effects of Mg deficiency in diabetic pregnancy from our results, but they show that the quality of the diet is of major importance in the manifestation of embryotoxicity in diabetes.     

Uteroplacental insufficiency affects kidney VEGF expression in a model of IUGR with compensatory glomerular hypertrophy and hypertension

Low nephron endowment secondary to intrauterine growth restriction (IUGR) results in compensatory hypertrophy of the remaining glomeruli, which in turn is associated with hypertension. However, gender differences exist in the response of the kidney to injury, and IUGR female offspring seems protected from an unfavorable outcome. We previously reported differences in gender-specific gene expression in the IUGR kidney as well as increased circulating corticosterone levels following uteroplacental insufficiency (UPI). Vascular endothelial growth factor (VEGF), which is critical for renal development, is an important candidate in the IUGR kidney since its expression can be regulated by sex-steroids and glucocorticoids. We hypothesize that IUGR leads to altered kidney VEGF expression in a gender-specific manner. Following uterine ligation in the pregnant rat, UPI decreases renal VEGF levels in male and female IUGR animals at birth and through postnatal day 21. However, by day 120 of life, IUGR females have increased kidney VEGF expression, not present in the IUGR males. In addition, IUGR males exhibit increased serum testosterone levels as well as proteinuria. These findings are intriguing in light of the difference in glomerular hypertrophy observed: IUGR males show increased glomerular area when compared to IUGR females. In this model characterized by decreased nephron number and adult onset hypertension, UPI decreases renal VEGF expression during nephrogenesis. Our most intriguing finding is the increased renal VEGF levels in adult IUGR females, associated with a more benign phenotype. We suggest that the mechanisms underlying renal disease in response to IUGR are most likely regulated in a gender specific manner.     

Nephron endowment and filtration surface area in the kidney after growth restriction of fetal sheep

Low birth weight is associated with adult-onset diseases including hypertension and renal disease; altered renal development after intrauterine growth restriction (IUGR) may underlie such prenatal programming. Our aim was to investigate nephron endowment and renal filtration surface area in fetal sheep in which IUGR resulted from late gestational umbilico-placental embolization (UPE) or natural twinning. UPE was performed between 120 and 140 d of gestation (term approximately 147 d). At autopsy (140 d), body weights of UPE and twin fetuses were, respectively, 34% and 28% lower than controls. Kidneys were sampled using a smooth fractionator approach and glomerular number was estimated using a physical disector/fractionator technique. Glomerular capillary length and filtration surface area were estimated using unbiased stereological techniques. Although relative kidney weights (grams per kilogram body weight) were not different between groups, nephron endowment was 40% lower in twin fetuses compared with controls (34.3 +/- 10.6 x 10(4) and 55.9 +/- 19.8 x 10(4), respectively; p < 0.05); UPE did not alter nephron number (50.7 +/- 13.2 x 10(4)). There was no difference in the glomerular capillary length or surface area between the UPE and control fetuses. IUGR due to twinning leads to reduced nephron endowment whereas late gestational IUGR does not, suggesting that reduced nephron endowment is dependent on the timing of the growth restriction. Our findings demonstrate that reduced birth weight per se does not necessarily imply reduced nephron endowment.     

Thyroxine treatment in acute renal failure (author's transl)]

8 patients suffering from acute renal failure (shock kidney) with anuria extending over 3 to 5 days, were treated with L-thyroxine for 5 to 9 days (5-6 mug per kg body weight per day orally). Diuresis was restored within 34 to 46 hrs. Plasma levels of urea and creatinine decreased earlier and much more rapidly to normal than was to be expected from the natural history of the disease, indicating the prompt and extensive increase of glomerular filtration rate. Polyuria seemed less pronounced and also shortened as compared with the ordinary course of that form of sudden renal insufficiency. Obviously, the well-known diuretic response in the normal individual to high doses of thyroid hormones in not a factor in the induction of diuresis in acute renal failure. The tendency with L-thyroxine treatment to dilate the preglomerular arterial vessel is considered a consequence of the stimulation of sodium reabsorption in the upper nephron. High values of RPF and GFR, regularly observed in hyperthyroidism or after L-thyroxine administration, do not depend on any augmentation of cardiac output or on arterial hypertension, since such symptoms were missed in our patients and, in our view, such an interpretation is excluded by the very existence of the so-called autoregulation of the kidney which leaves RPF (and therefore GFR) independent of systemic blood pressure. The same intrarenal feed-back mechanism, normally adapting the glomerular blood supply to the resorptive capacity of the proximal-tubular epithelium (mediation via the juxta-glomerular apparatus), is responsible for the GFR- and RPF-raising effect of exogenous L-thyroxine in the intact kidney as well as in acute renal failure: both sodium reabsorption and sodium filtration are accelerated.--The special conditions under which L-thyroxine interferes with the pathogenetic process of acute renal failure, the latter being characterised by the critical insufficiency of tubular sodium reabsorption and therefore by preglomerular arterial constriction, is discussed on the basis of a new hypothesis concerning the thyrogenic nephrotropic effects in general.     

Perinatal salt restriction: a new pathway to programming insulin resistance and dyslipidemia in adult wistar rats

Several studies support the hypothesis that chronic diseases in adulthood might be triggered by events that occur during fetal development. This study examined the consequences of perinatal salt intake on blood pressure (BP) and carbohydrate and lipid metabolism in adult offspring of dams on high-salt [HSD; 8% (HSD2) or 4% (HSD1)], normal-salt (NSD; 1.3%), or low-salt (LSD; 0.15% NaCl) diet during pregnancy and lactation. At 12 wk of age, female Wistar rats were matched with adult male rats that were fed NSD. Weekly tail-cuff BP measurements were performed before, during, and after pregnancy. After weaning, the offspring received only NSD and were housed in metabolic cages for 24-h urine collection for sodium and potassium and nitrate and nitrite excretion measurements. At 12 wk of age, intra-arterial mean BP was measured, a euglycemic-hyperinsulinemic clamp was performed, and plasma lipids and nitrate and nitrite concentrations were determined. Tail-cuff BP was higher during pregnancy in HSD2 and HSD1 than in NSD and LSD dams. Mean BP (mm Hg) was also higher in the offspring of HSD2 (110 +/- 5) and HSD1 (107 +/- 5) compared with NSD (100 +/- 2) and LSD (92 +/- 2). Lower glucose uptake and higher plasma cholesterol and triacylglycerols were observed in male offspring from LSD dams (glucose uptake: HSD2 17 +/- 4, HSD1 15 +/- 3, NSD 11 +/- 3, LSD 4 +/- 1 mg . kg(-1) . min(-1); cholesterol: HSD2 62 +/- 6, HSD1 82 +/- 11, NSD 68 +/- 10, LSD 98 +/- 17 mg/dL; triacylglycerols: HSD2 47 +/- 15, HSD1 49 +/- 12, NSD 56 +/- 19, LSD 83 +/- 11 mg/dL). In conclusion, maternal salt intake during pregnancy and lactation has long-term influences on arterial pressure, insulin sensitivity, and plasma lipids of the adult offspring.     

Dietary flax oil during pregnancy and lactation retards disease progression in rat offspring with inherited kidney disease

Dietary flax oil (FO) retards disease progression in growing or adult animal models of kidney disease. To determine whether dietary flax oil during the perinatal period would alter renal disease progression in offspring, Han-SPRD-cy rats with inherited cystic kidney disease were given diets with either 7% FO or corn oil (CO), throughout pregnancy and lactation. At 3 wk of age, offspring were then given either the same or the alternate diet for 7 wk. Rats given FO during the maternal period had 15% less renal cyst growth compared with rats given FO only in the postweaning period. Dietary FO, compared with CO, in the maternal period also resulted in 12% lower cell proliferation and 15% less oxidant injury in diseased kidneys of offspring. Including FO in both the maternal and postweaning period resulted in 29-34% less renal interstitial fibrosis and 22-23% lower glomerular hypertrophy. Along with improved histology, these rats exhibited 13% less proteinuria and 30% lower creatinine clearance when dietary FO was given in the maternal period. The potential for dietary FO during pregnancy and lactation to positively modulate adult renal disease has significant implications for the 1 in 1000 individuals with congenital cystic kidney disease.     

The influence of L-arginine on blood pressure, vascular nitric oxide and renal morphometry in the offspring from diabetic mothers

The present study was designed to evaluate the effects of L-arginine (L-arg) supplementation on blood pressure, vascular nitric oxide content, and renal morphometry in the adult offspring from diabetic mothers. Diabetes mellitus was induced in female rats with a single dose of streptozotocin (50 mg/kg), before mating. The offspring was divided into four groups: group C (controls); group DO (diabetic offspring); group CA (controls receiving 2% L-arg solution dissolved in 2% sucrose in the drinking water) and group DA (DO receiving the L-arg solution). Oral supplementation began after weaning and continued until the end of the experiments. In DO, hypertension was observed, from 3 mo on. In DA, pressure levels were not different from C and CA. In 6-mo-old animals, basal NO production (assessed by DAF-2) was significantly depressed in DO in comparison to controls. The NO production was significantly increased after stimulation with Ach or BK in all groups, the increase being greater in control than in DO rats. L-arg was able to improve the NO production and to prevent the glomerular hypertrophy in the DO. Our data suggest that the bioavailability of NO is reduced in the DO, because L-arg corrected both the hypertension and glomerular hypertrophy.     

早期干预对边缘型维生素A缺乏幼鼠学习记忆的影响及机制研究

目的观察边缘型维生素A缺乏幼鼠早期维生素A(VA)干预后,其学习记忆的恢复情况,并对其机制进行初步探讨。方法实验分为正常对照组、边缘型维生素A缺乏组(MVAD组)、胚胎干预组(VAI1组)和新生干预组(VAI2组)。正常对照组(幼鼠10只)母鼠和幼鼠均给予VA充足饲料;MVAD组(幼鼠19只)母鼠和幼鼠均给予边缘型维生素A缺乏饲料;VAI1组(幼鼠10只)母鼠给予边缘型维生素A缺乏饲料至孕14 d,后改饲VA充足饲料,幼鼠饲VA充足饲料。VAI2组(幼鼠13只)母鼠给予边缘型维生素A缺乏饲料至分娩,后改饲VA充足饲料,幼鼠饲VA充足饲料。待各组幼鼠长至7周龄,用穿梭箱主动回避反应实验测试学习记忆功能,离体脑片检测海马长时程增强(LTP),半定量RT-PCR技术检测RAR-α、RAR-β、RXR-β、RXR-γ、RC3和tTG mRNA的表达。结果(1)穿梭箱主动回避反应实验达到学会标准的训练次数:MVAD组[(45.6±12.1)次],多于正常对照组[(17.1±4.4)次](P<0.01),VAI1组[(20.8±3.1)次]和VAI2组[(22.1±4.0)次]均少于MVAD组(P<0.01),VAI1组和VAI2组比较及分别与正常对照组比较,差异均无统计学意义(P>0.05);(2)海马脑片诱发LTP的场兴奋性突触后电位(fEPSP)斜率增加的百分比:MVAD组[(22.9±9.4)%]和VAI2组[(39.1±4.3)%]均小于正常对照组[(57.5±27.3)%](P<0.05),VAI1组[(51.6±9.4)%]与正常对照组差异无统计学意义;(3)半定量RT-PCR结果:MVAD组的RAR-βmRNA和RXR-βmRNA表达与对照组比较,分别下降48.72%和37.84%(P均<0.05),VAI1组RAR-βmRNA表达与MVAD组比较,有增高的趋势(P=0.065);MVAD组的RC3 mRNA表达与对照组比较有降低趋势(P=0.061),MVAD组的RAR-αmRNA表达与对照组比较,有增高趋势(P=0.061);各组的RXR-γmRNA和tTG mRNA表达无明显差异(P>0.05)。结论早期VA干预可以使MVAD所致的学习记忆障碍行为基本恢复至正常水平,而新生干预不能使LTP恢复正常;VA可能主要通过受体RARα-、RAR-β和RXR-β调控RC3的表达,影响海马长时程增强,最终表现为学习记忆的改变。     

Reduced renal mass in early postnatal development. glomerular dynamics in the guinea pig

As shown previously in the neonatal guinea pig, unilateral nephrectomy at birth results in an earlier rise in superficial nephron glomerular filtration rate. To evaluate the role of glomerular dynamics in this compensatory adaptation, pressure gradients responsible for glomerular ultrafiltration in superficial nephrons were measured by micropuncture techniques in developing euvolemic guinea pigs subjected to uninephrectomy or sham operation at birth. Uninephrectomy resulted in a significant rise in mean arterial blood pressure and glomerular capillary pressure by 10 days of age. Effective filtration pressure was 30% higher in 10- and 21-day-old uninephrectomized guinea pigs compared to sham-operated littermates. However, there ws no significant increase in effective filtration pressure with normal growth from 10 to 21 days of age. Augmented pressure gradients for glomerular ultrafiltration therefore contribute significantly to early compensatory renal adaptation but not to the transitional sharp increase in superficial glomerular filtration which characterizes normal renal growth from 10 to 21 days of age. The apparent acceleration of functional glomerular maturation resulting from uninephrectomy of birth may result from the summation of differing responses to the demands of somatic growth and reduced renal mass.     

Paleonephrology and reflux nephropathy. From the 'big bang' to end-stage renal disease

Urinary tract infections, in association with ureteral reflux or dysperistalsis, may lead to invasive renal parenchymal infection and residual scarring (reflux nephropathy). Such infections in infants are often not diagnosed during the acute phase. Late sequelae of reflux nephropathy include hypertension, proteinuria, or chronic renal failure. The latter may eventuate in the subset of patients with urinary tract infection and unilateral reflux extending to a solitary kidney or bilateral reflux. Proteinuria may herald the inexorable progression of glomerular sclerosis in patients destined to progress to end-stage renal disease, despite the absence of further recurrences of urinary tract infections. The mechanism of progression is probably similar to that occurring in other forms of chronic, diffuse parenchymal renal disease, which all have similar alterations in glomerular hemodynamics (an increase in glomerular capillary flow, pressure, and filtration). The consequent hyperfiltration per nephron may be related to the level of dietary protein intake or to some derivative of the protein load. Hyperfiltration appears to recapitulate the presumed renal hemodynamic response to the relatively high level of episodic meat consumption by paleolithic hunter-gatherers. A prudent therapeutic intervention in children with progressive reflux nephropathy may be a proportional reduction in protein intake.     

Hypertension and microalbuminuria in children with congenital solitary kidneys

Aim:   According to the hyperfiltration hypothesis, a low nephron endowment will lead to hyperfiltration in the remaining glomeruli and is associated with systemic hypertension, proteinuria and glomerulosclerosis. Being born with one functioning kidney instead of two, for instance because of unilateral renal agenesis or multicystic dysplastic kidney, is a cause of congenital renal mass reduction.
Methods:   In order to study the effect of congenital renal mass reduction on renal function and blood pressure, a retrospective chart review of 66 patients at the Pediatric Renal Center of the VU University Medical Center was performed. As intrauterine growth restriction is associated with a low nephron endowment, the additional effect of birthweight was also studied.
Results:   A total of 50% of patients with congenital renal mass reduction is found to be hypertensive, using anti-hypertensive drugs, and/or having microalbuminuria (>20 μg/min). Patients born small for gestational age have significantly smaller kidneys and lower estimated glomerular filtration rate than patients with a normal birthweight.
Conclusions:   We conclude that microalbuminuria and/or hypertension is present in 50% of patients with congenital solitary kidneys, which warrants a systematic follow-up of blood pressure, proteinuria and renal function in all patients with congenital solitary functioning kidneys, especially in patients with a low birthweight.     

孕期和哺乳期轻度缺锌对仔鼠学习记忆能力的影响

目的探讨孕期和哺乳期母鼠缺锌对仔鼠幼年期学习记忆能力的影响。方法怀孕1 d的孕鼠随机分为轻度缺锌组和对照组,每组3只。缺锌饲料、正常饲料含锌量分别为5 mg/kg、25 mg/kg。产后每窝随机保留4只。至21 d断乳去母鼠,每组12只仔鼠,继续饲以缺锌和正常饲料,分别于28 d及58 d以Morris水迷宫测试仔鼠的短期及长期学习记忆能力。结果学习获得实验(短期记忆)及记忆保持实验(长期记忆):对照组定位能力较好,游泳轨迹以目标象限为主;而缺锌组定位能力较差,游泳轨迹比较分散;缺锌组仔鼠找到平台的潜伏期、总游程大于对照组(P<0.01);两组游速的差异无统计学意义(P>0.05)。随着训练天数的增加,对照组上述各项记录都随着训练天数增加而变化,其中潜伏期和总游程随着训练天数增加而逐步减少,游泳速度、目标象限游程占总游程的百分比随着训练天数的增加而增加,缺锌组的变化趋势不如对照组明显。结论孕期及哺乳期母鼠轻度缺锌影响仔代生长期幼鼠短期与长期学习记忆能力。     

三聚氰胺致大鼠泌尿系结石肾脏损害及病理改变的实验研究

目的 建立三聚氰胺泌尿系结石大鼠模型,观察肾脏病理改变,初步探讨三聚氰胺亚慢性肾脏毒性的可能机制。方法 将3周龄刚断乳雄性Wistar大鼠60只按随机数字表法分为实验组2组（A、B组）和对照组（C组）,每组20只,A、B、C组分别给予三聚氰胺质量分数为1％、2％、0的饲料。比较大鼠体重、摄食量、血清尿素氮和肌酐水平。15周时（用药期末）3组各随机选取半数处死,剩余半数停药继续喂养4周后（停药期末）处死,均行肾脏重量、系数比较并观察病理改变。采用高效液相色谱-质谱联用法检测血清和结石中三聚氰胺、三聚氰酸和尿酸含量。结果 用药期末,A、B组血清尿素氮水平分别为( 13.23 ±5.10)、( 18.30 ±5.90) mmol/L,均高于C组(8.23 ±2.30) mmol/L(P＜0.01);B组肌酐水平(19.90 ±2.90) mmoL/L高于C组(10.04±1.73) mmol/L(P＜0.01);A、B组左右肾系数均高于C组(P＜0.01);肾脏中可见结晶形成,结晶所在肾小管扩张明显,肾小管周围肾间质淋巴细胞浸润及间质纤维化,B组最为显著。停药期末,A、B组血清尿素氮水平分别为(17.96±2.04)、(19.20±3.36) mmol/L,均高于C组的（8.30±1.79）mmol/L(均P＜0.01);B组肌酐水平(24.20±5.28) mmol/L高于C组(9.87 ±2.71) mmol/L(P ＜0.01),且分别较用药期水平升高（分别为P＜0.01,P＜0.05）;两实验组肾脏系数较前下降;肾脏仍有结晶未排出,间质改变较停药前未见减轻。结论(1)饲喂3周龄刚断乳雄性Wistar大鼠含三聚氰胺质量分数为2％的饲料15周能够建立三聚氰胺泌尿系结石模型。饲喂含三聚氰胺质量分数为1％的饲料15周,仅少数大鼠可形成肉眼可见的肾脏结石,部分形成镜下结晶。结石成分主要为三聚氰胺(＞90％)、少量尿酸及极少量三聚氰酸。(2)三聚氰胺可导致大鼠肾功能受损,镜下可见肾小管结晶形成、肾小管扩张、炎症、纤维化等病理表现,并具有剂量依赖性。三聚氰胺的肾脏损害与结晶、结石梗阻有一定相关性。(3)停止摄入三聚氰胺后,肾功能及肾脏炎症、纤维化等改变短期内未见好转,结晶自行排出的过程较为缓慢,如结晶持续存在可能会造成进一步的或不可逆转的肾脏损伤。     

Renal effects of theophylline and caffeine in newborn rabbits

Renal hemodynamics and functions were assessed in four groups of anaesthetized newborn rabbits receiving a single intravenous dose of methylxanthines, i.e.: aminophylline: 3 mg/kg (A1) or 6 mg/kg (A2); sodium benzoate caffeine: 5 mg/kg (C1) or 10 mg/kg (C2). Each animal acted as its own control. The mean PAH extraction ratio was not modified by the methylxanthines. Renal blood flow and glomerular filtration rate were determined by clearances of para-aminohippuric acid and inulin, respectively. No changes in renal hemodynamics or renal functions were observed in group C1. In group C2, renal blood flow and filtration fraction did not vary significantly but renal vascular resistance showed a delayed increase. Systemic infusion of the two aminophylline regimens induced a delayed increase in renal vascular resistance with a concomitant fall in renal blood flow and an increase of filtration fraction in group A2. Glomerular filtration rate was either reduced (3 mg/kg aminophylline) or increased (6 mg/kg aminophylline and 10 mg/kg caffeine). Moreover, diuresis increased and tubular water reabsorption declined in groups A1, A2, and C2. High dose caffeine enhanced sodium fractional excretion. The acute renal effects of methylxanthines appeared dose- and time-related in immature animals and caffeine proved safer than aminophylline at doses used in human neonates.