Failures of intravenous Rh immune globulin prophylaxis: an analysis of the reasons for such failures

Universal administration of an ion exchange column prepared Rh immune globulin (RhIG-IV) antepartum at 28 weeks' gestation and postpartum to 9,295 Rh negative women delivering Rh positive babies has reduced the prevalence of Rh immunization from the expected 601 to 25 (a protection rate of 95.9%). Rh immunization, despite universal Rh prophylaxis, developed in 25 women; eight before antenatal prophylaxis was administered, 17 after antenatal prophylaxis was administered. Residual Rh immunization is caused by small fetal transplacental hemorrhages (TPH) (greater than or equal to 0.01 mL of fetal blood) before antenatal prophylaxis (15%) and by significant fetal TPH (greater than or equal to 0.05 mL of fetal blood) between 30 and 38 weeks' gestation (18%); TPH was too great, in some instances, for residual passive Rh antibody to give protection. Although a reduction of 62% (five of eight) of early Rh immunization and 82% (14 of 17) of later Rh immunization might be achieved by addition of 16 weeks' to 20 weeks' gestation and 34 weeks' gestation Rh prophylaxis; and a reduction of 84% overall (21 of 25) might be achieved by universal fetal TPH screening every 2 weeks from 10 weeks' gestation until delivery, with administration of RhIG when a small early fetal TPH or a significant later fetal TPH is detected, all of these programs are costly in terms of prevention of perinatal mortality and in terms of cost per quality adjusted life year gained. We believe that the costs outweigh the benefit that would be achieved. Therefore, a residual Rh immunization prevalence of 0.24% to 0.31% during or after each Rh positive pregnancy in patients at risk is to be expected despite universal 28 weeks' gestation antenatal and postnatal Rh prophylaxis.     

Intrauterine growth restriction promotes vascular remodelling following carotid artery ligation in rats

Epidemiological studies revealed an association between IUGR (intrauterine growth restriction) and an increased risk of developing CVDs (cardiovascular diseases), such as atherosclerosis or hypertension, in later life. Whether or not IUGR contributes to the development of atherosclerotic lesions, however, is unclear. We tested the hypothesis that IUGR aggravates experimentally induced vascular remodelling. IUGR was induced in rats by maternal protein restriction during pregnancy (8% protein diet). To detect possible differences in the development of vascular injury, a model of carotid artery ligation to induce vascular remodelling was applied in 8-week-old intrauterine-growth-restricted and control rat offspring. Histological and immunohistochemical analyses were performed in the ligated and non-ligated carotid arteries 8 weeks after ligation. IUGR alone neither caused overt histological changes nor significant dedifferentiation of VSMCs (vascular smooth muscle cells). After carotid artery ligation, however, neointima formation, media thickness and media/lumen ratio were significantly increased in rats after IUGR compared with controls. Moreover, dedifferentiation of VSMCs and collagen deposition in the media were more prominent in ligated carotids from rats after IUGR compared with ligated carotids from control rats. We conclude that IUGR aggravates atherosclerotic vascular remodelling induced by a second injury later in life.     

超声引导羊膜腔内营养治疗改善宫内发育迟缓仔兔心肺

目的探讨羊膜腔内营养治疗对宫内发育迟缓(IUGR)仔兔心肺发育的影响。方法健康新西兰兔(孕25 d)15只,随机分为:正常组、建立IUGR模型组、建立IUGR模型+羊膜腔注射营养素组,每组5只。于妊娠30 d剖宫产出仔兔,分别分为A、B、C组,测量三组仔兔身长、体质量、胎盘质量、支气管肺泡灌洗液中二棕榈胆碱酯磷酸(DPPC)的含量,通过后期处理病理图像评估心肺成熟程度、检测肺表面活性蛋白A(SP-A)的含量及心肌凋亡细胞数量等。结果(1)B组IUGR发生率高于A组(P<0.05)。(2)B组肺合成、分泌DPPC及SP-A低于A组(P<0.05),C组肺合成、分泌DPPC、SP-A的含量高于B组(P<0.05),仍未达到A组水平(P<0.05);B组肺间质比例高于A组(P<0.05),C组肺间质比例低于B组(P<0.05),仍高于A组(P<0.05)。(3)A组心肌细胞几乎没有凋亡细胞,B组心肌凋亡细胞数目高于A组,C组心肌凋亡细胞低于B组但高于A组,B组心肌损伤评分高于A组(P<0.05)。结论超声引导羊膜腔内营养素治疗可作为有效的产前治疗对IUGR仔兔的心脏及肺发育起促进作用。     

早产危险因素的1∶1病例对照研究

目的 探讨早产的主要危险因素,为降低早产发生率提供理论依据。方法 系统抽样选取2018年1月1日至2018年12月31日青岛大学附属医院新生儿科NICU收治122例早产儿和122例足月儿及产妇进行问卷调查。分析早产危险因素。结果 早产组的产妇在多胎妊娠、胎盘异常、宫颈机能不全、胎儿宫内窘迫、妊娠期高血压、试管婴儿、胎膜早破、阴道流血、居住在乡镇及农村的比例高于足月组(P均<0.05),是新生儿早产的独立危险因素。结论 产妇存在多胎妊娠、胎盘异常、宫颈机能不全、胎儿宫内窘迫、妊娠期高血压、试管婴儿、胎膜早破、阴道流血、居住在乡镇及农村是新生儿早产的危险因素。     

Tumor Necrosis Factor-α and Pregnancy Complications: A Prospective Study

Objective

The aim of this study was to compare the levels of tumor necrosis factor-α (TNF-α) produced by peripheral blood mononuclear cells in normal pregnancies and pregnancies with complications.

Materials and Methods

Maternal peripheral blood mononuclear cells from women with a recurrent spontaneous miscarriage (n = 35), premature rupture of fetal membranes (n = 30), preeclampsia (n = 27) and intrauterine fetal growth retardation (IUGR; n = 36) were stimulated with mitogen or antigen, and the levels of TNF-α produced were compared to those produced by peripheral blood mononuclear cells from a normal pregnancy (n = 35).

Results

The median levels of mitogen-induced TNF-α at the 1st, 2nd and 3rd trimester, and at normal delivery were 1,176.4, 4,320.9, 7,307.4 and 2,463.0 pg/ml, respectively, while those produced in the recurrent spontaneous miscarriage, premature rupture of membranes and preeclampsia cases were 4,159.8, 3,489.5 and 4,149.2 pg/ml, respectively. The differences were statistically significantly higher in these pregnancy complications (p = 0.04, 0.024 and 0.014) as compared to the levels in normal pregnancy. Furthermore, antigen-induced TNF-α levels were produced at statistically significantly higher levels by women with IUGR (120.4 pg/ml) compared to women with normal pregnancies (17.9 pg/ml; p = 0.041).

Conclusion

Higher levels of TNF-α seem to play a role in these pregnancy complications, suggesting its pathogenesis in such conditions.Key Words: Cytokines, Intrauterine fetal growth retardation, Preeclampsia, Recurrent spontaneous miscarriage, Tumor necrosis factor-α     

Antenatal Transplacental Hemorrhage

A transplacental hemorrhage of approximately 10 ml occurred at the 29th week of the first pregnancy of a woman carrying twins. The administration of 400 μg Rh immunoglobulin 96 hours later failed to prevent primary immunization. Traces of saline‐reacting anti‐Rh₀ (D) were detectable by the 32nd week, increasing to a titer of 1 : 64 by the 37th week of pregnancy. The possibility that antenatal administration of Rh immunoglobulin may enhance the risk of primary immunization is considered.     

Uterine and umbilical artery flow velocity waveform analysis in pregnancies complicated by chronic hypertension or preeclampsia

Using continuous wave Doppler ultrasound, we studied the umbilical and uterine flow velocity waveforms in 68 pregnant women who had chronic hypertension and/or preeclampsia. The systolic-diastolic (S/D) ratio was considered an expression of vascular resistance peripheral to the point of insonation. Abnormal umbilical artery S/D ratio (greater than 95th percentile) alone or with abnormal uterine artery S/D ratio was associated with poor pregnancy outcome as judged by incidence of intrauterine growth retardation (IUGR), cesarean section rate, birth weight, perinatal morbidity and mortality, and prematurity. In patients with preeclampsia and abnormal Doppler values, pregnancy outcome was poor, whereas in those with normal Doppler values, pregnancy outcome approached normal. The same relationship was also found in patients with chronic hypertension. The sensitivity and specificity for the prediction of IUGR by the umbilical artery S/D ratio alone was 71% and 93%, respectively. The uterine artery S/D ratio alone yielded a 66% sensitivity and 64% specificity, and when both tests were taken into account, the sensitivity increased to 75% and the specificity to 100%. Abnormal umbilical and uterine artery S/D ratios were associated with 100% IUGR and 25% perinatal mortality. We conclude that in pregnant women with hypertensive disorders there is a significant difference in pregnancy outcome between those with normal and those with abnormal Doppler values. Umbilical artery S/D ratio alone is a better predictor of IUGR and poor pregnancy outcome than the uterine artery S/D ratio.     

Circadian rhythm of maternal blood pressure and fetal growth

This study aimed at examining any relation between the circadian variation in blood pressure (BP) in human pregnancy and fetal growth. A prospective study included 52 pregnant women monitored during the third trimester of pregnancy. There were 33 uncomplicated pregnancies with normal fetal growth (Group 1) and 19 pregnancies complicated by intrauterine growth retardation (IUGR), confirmed at birth (Group 2). Ten women (five in each group) had pregnancy-induced hypertension. All women were hospitalized and followed a similar daily routine. BP was recorded with an automatic wearable device. Measurements were obtained every 20 min for 24 ± 1 h. BP profiles were analyzed by conventional statistical methods and by cosinor, involving the least squares fit of cosine curves with an anticipated period (24 h) to the data. BP parameters, fetal outcome, demographic and obstetric characteristics were compared between the two groups. Logistic regression and multivariate analyses were used to assess factors putatively associated with fetal outcome. The circadian amplitude of diastolic BP was found to be larger in normotensive women with IUGR. As gauged by odds ratios (OR), the circadian amplitude of diastolic BP (OR = 1.7, 95% CI: 1.1–2.8; P = 0.03) and hematocrit (OR = 1.4, 95% CI: 1.0–1.9; P = 0.04) were the only variables positively and independently associated with IUGR. In the presence of maternal hypertension, the circadian amplitude of systolic BP was negatively associated with IUGR (OR = 0.7, 95% CI: 0.5–1.0; P = 0.03). A larger circadian variation in diastolic BP, rather than a difference in the mean value of systolic or diastolic BP, was found to be statistically significantly associated with IUGR. This study adds another condition in which the circadian BP amplitude constitutes a harbinger of elevated risk, apart from an association with a shortened lifespan in the absence or presence of malignant hypertension and with an increased risk of stroke and nephropathy reported earlier.     

宫外生长发育迟缓早产儿1岁内生长发育迟缓发生情况及其影响因素

目的分析宫外生长发育迟缓（EUGR）早产儿出院后校正年龄1岁内生长发育迟缓发生情况及其影响因素。 方法选取2014年7月至2017年12月在泰安市中心医院新生儿重症监护治疗病房（NICU）住院治疗且正常出院的90例EUGR早产儿。对90例EUGR早产儿在校正年龄1岁内进行定期随访，测量体质量、身长、头围等，并收集相关临床资料，如喂养情况、疾病情况、前白蛋白量、元素锌含量等，分析出院后EUGR早产儿校正年龄1岁内生长发育迟缓发生情况及其影响因素。采用t检验比较生长发育迟缓患儿和非生长发育迟缓患儿母亲年龄、出生体质量、出院体质量、胎龄、住院时间、达完全肠内营养时间、血前白蛋白、血锌等指标的差异。采用χ²检验比较生长发育迟缓患儿和非生长发育迟缓患儿双胎、妊娠高血压综合征、糖尿病、胎膜早破、宫内生长发育迟缓（IUGR）、窒息、剖宫产、新生儿呼吸窘迫综合征（NRDS）、支气管肺发育不良（BPD）、新生儿坏死性小肠结肠炎（NEC）、应用有创呼吸机、贫血、感染等的发生情况以及不同喂养方式的差异。对生长发育迟缓的高危因素进行logistic回归分析。 结果对EUGR早产儿随访时间点为校正年龄1个月、6个月、12个月，分别为90例、86例、70例，生长发育迟缓发生率分别为48.9%（44/90）、30.2%（26/86）、17.1%（12/70）。在校正年龄1个月时，与非生长发育迟缓患儿相比较，生长发育迟缓患儿IUGR、NRDS、BPD、应用有创呼吸机的发生率明显增高，差异有统计学意义（χ²=10.146，P=0.001；χ²=7.479，P=0.006；χ²=14.407，P<0.001；χ²=10.500，P=0.001）；出生体质量、出院体质量、胎龄、血前白蛋白明显降低，差异有统计学意义（t=-4.945，P<0.001；t=-3.522，P=0.001；t=-2.047，P=0.044；t=-2.312，P=0.023）；住院时间、达完全肠内营养时间明显延长，差异有统计学意义（t=3.797，P<0.001；t=2.840，P=0.006）；在喂养方式方面明显不同，差异有统计学意义（χ²=7.060，P=0.029）。logistic回归分析表明，生长发育迟缓与达完全肠内营养时间（P=0.040）、IUGR（P<0.001）及BPD（P=0.011）有显著相关性。在校正年龄6个月时，与非生长发育迟缓患儿相比较，生长发育迟缓患儿IUGR、NRDS、BPD、应用有创呼吸机的发生率明显增高，差异有统计学意义（χ²=8.474，P=0.004；χ²=12.613，P<0.001；χ²=24.398，P<0.001；χ²=12.662，P<0.001）；出生体质量、出院体质量、胎龄、血前白蛋白明显降低，差异有统计学意义（t=-5.849，P<0.001；t=-3.211，P=0.002；t=-3.405，P=0.001；t=-2.636，P=0.010）；住院时间、达完全肠内营养时间明显延长，差异有统计学意义（t=5.351，P<0.001；t=3.095，P=0.003）。logistic回归分析表明，生长发育迟缓与出生体质量（P=0.013）、IUGR（P=0.001）及BPD（P=0.022）有显著相关性。在校正年龄12个月时，与非生长发育迟缓患儿相比较，生长发育迟缓患儿IUGR、NRDS、BPD的发生率明显增高，差异有统计学意义（χ²=4.050，P=0.044；χ²=5.737，P=0.017；χ²=8.393，P=0.004）；出生体质量、胎龄、前白蛋白明显降低，差异有统计学意义（t=-3.192，P=0.002；t=-2.271，P=0.026；t=-3.509，P=0.001）；住院时间明显延长，差异有统计学意义（t=3.133，P=0.003）。logistic回归分析表明，生长发育迟缓与IUGR（P=0.040）及BPD（P=0.003）有显著相关性。 结论NICU出院的EUGR早产儿是一组特殊的高危人群，IUGR、BPD是出院后发生生长迟缓的持续危险因素。     

Intrauterine growth retardation index

SUMMARY: The objective of the study discussed was to develop an intrauterine growth retardation (IUGR) index to detect fetuses with IUGR. The study was conducted in Australia and was based on 219 pregnant women at Wollongong Hospital in the Illawarra region in New South Wales, Australia. Overall, 21 variables, including ultrasonographic variables and risk factors for IUGR, related to IUGR were tested in the sample. The results of discriminant analysis showed that hypertension, amniotic fluid index, abdominal circumference, head circumference, head circumference-to-abdominal circumference ratio, and low maternal weight gain in pregnancy have the highest F values. That means that these parameters were the most important predictors of IUGR in fetuses. An IUGR score was developed using these parameters. The developed index in this study has a reasonably high sensitivity (89.1%) and specificity (71.8%) in detecting IUGR in fetuses, compared with the developed indices to date. The IUGR score includes both ultrasonographic and maternal risk factor variables. This combination increases the accuracy of identification of IUGR in fetuses.     

妊娠合并乙型肝炎病毒感染对妊娠结局的影响

目的探讨妊娠合并乙型肝炎病毒（HBV）感染影响妊娠结局的有关因素。方法回顾性分析对比200例妊娠期存在HBV感染者与200例正常产妇的临床资料。结果①并发症（早产、胎膜早破、产后出血、妊娠高血压综合征）的发生率以肝功能异常组发病率最高,无症状HBV感染组次之,正常妊娠组最低,其差异有统计学意义（P〈0.05）。②新生儿异常发生率（死胎、低体重儿、新生儿窒息等）肝功能异常组与其他两组之间比较差异有统计学意义（P〈0.05）,而无症状HBV感染组与正常妊娠组比较差异无统计学意义（P〉0.05）。结论妊娠合并HBV感染,易发生早产、胎膜早破、产后出血、妊娠高血压综合征等并发症,肝功能异常对这些妊娠并发症的发生有显著影响,新生儿异常发生率仅与肝功能异常有关。     

The risk of alloimmunization to c (Rh4) in R1R1 patients who present with anti-E

BACKGROUND: Because the Rh antigens E (Rh3) and c (Rh4) are relatively immunogenic, it has been suggested that R1R1 (E-, c-) patients who present with anti-E alone receive prophylactic c- (Rh: -4) red cell transfusions. STUDY DESIGN AND METHODS: To determine the utility of this approach, the transfusion records of 100 consecutive R1R1 patients with anti-E identified over a 6-year period were reviewed. RESULTS: Thirty-two (32%) had anti-c concurrent with anti-E. Twenty-seven of the 68 patients who presented with anti-E alone received random (i.e., not typed for c [Rh4]) red cell transfusions. Five (18.5%) of the 27 subsequently developed anti-c 13 to 193 days (mean, 50) after transfusion of 2 to 14 (mean, 8) red cell units. None of the five had clinical evidence of hemolysis that could be attributed to a delayed hemolytic transfusion reaction. Twenty-two (81.5%) of the 27 failed to develop anti-c even after transfusion of 1 to 41 (mean, 9; median, 7) red cell units. CONCLUSION: The overall rate of immunization to c (Rh4) antigen in R1R1 patients with anti-E was 37 percent. Production of anti- c following transfusion to R1R1 patients with anti-E occurred in 18.5 percent of the cases in this series, which could have been avoided by the prophylactic use of R1R1 (E-, c-) blood for transfusion. The prophylactic use of c- (Rh: -4) blood in this patient population may be justified by the high immunization rate and the potential risk of delayed hemolytic transfusion reaction.     

Intrauterine growth restriction and placental location.

OBJECTIVE: The purpose of this study was to determine whether an association exists between intrauterine growth restriction (IUGR) and second-trimester placental location. METHODS: A case-control study was performed in well-dated singleton pregnancies with (n = 67) and without (n = 205) IUGR (defined as estimated fetal weight <10th percentile for gestational age at the last sonographic examination) to investigate the association between IUGR and placental location. Placental location was determined by sonography at 16 to 20 weeks' gestation. Maternal, perinatal, and delivery characteristics were abstracted from medical records. Group comparisons were made by the Student t test, chi(2) analysis, the Fisher exact test, the Wilcoxon test, and analysis of variance. Multivariable logistic regression analysis was used to determine the relationship between IUGR and placental location. RESULTS: In both groups, the most common placental locations in the second trimester were anterior and posterior. After adjusting for potential confounders (including race, chronic hypertension, and hypertensive disorders of pregnancy), IUGR pregnancies were nearly 4-fold more likely to have lateral placentation (odds ratio, 3.8; 95% confidence interval, 1.3-11.2) compared with anterior or posterior placentation. CONCLUSIONS: Pregnancies complicated by IUGR are significantly more likely than non-IUGR pregnancies to have lateral placentation in the second trimester.     

Lung fractional moving blood volume in normally grown and growth restricted foetuses

OBJECTIVE: To examine foetal lung blood perfusion using power Doppler ultrasound (PDU) and to compare fractional moving blood volume (FMBV) and mean pixel intensity (MPI) estimations in the lungs of normally grown (NG) foetuses and foetuses with intrauterine growth restriction (IUGR) and also to correlate foetal lung FMBV and MPI with respiratory complications after birth. METHODS: Lungs of 47 NG and 25 IUGR foetuses after 32 weeks of gestation were examined with PDU. FMBV and MPI were estimated in a defined region in the posterior part of the foetal lung closest to maternal abdominal wall. FMBV and MPI were correlated to foetal weight deviation and gestational age. Perinatal outcome and respiratory complications after birth were recorded in both groups. RESULTS: There were significantly lower FMBV and MPI values in IUGR than in NG foetuses. The overall variation was lower for FMBV than for MPI. There was a slightly higher correlation between FMBV and foetal weight deviation [r = 0.33, 95% confidence intervals (CI) 0.11-0.52] than between MPI and foetal weight deviation (r = 0.26, 95% CI 0.03-0.46). There was no significant correlation between FMBV or MPI and gestational age. No differences between the groups were found in the rate of respiratory complications, and they were not correlated either to the FMBV or MPI. CONCLUSION: FMBV and MPI, estimated from the PDU signals of foetal lung circulation, showed lower values in third-trimester pregnancies complicated by IUGR. The frequency of neonatal respiratory complications was not increased in cases with low pulmonary FMBV and MPI values.     

Studies on Rh Prophylaxis

The incidence of Rh immunization of Rh-negative volunteers given approximately 500 ml of Rh-positive blood is 18 out of 22. Complete Rh immune suppression was achieved in a treated group given a precalculated dose of Rh immune globulin. Rh immune prophylaxis is safe, effective and practical after transfusion accidents or massive fetomaternal hemorrhages where large volumes of Rh-positive blood enter the circulation of Rh-negative individuals.
The dose of RhoGAM,* Rho(D) Immune Globulin (Human) found to be effective in suppressing an immune response to the Rh factor was 20 μg/ml of red blood cells (not whole blood). Since each vial contains no less than 300 μg of anti-Rho(D), the potency for RhoGAM is 15 ml of red blood cells/vial.     

Isolation and purification of the Rh(D) blood group receptor component from human erythrocyte membrane

The Rh(D) antigen of human red blood cell membranes has been isolated as a homogeneous immunologically intact component. The method of preparation was as follows: Red cell membranes were prepared free of hemoglobin and components were solubilized using ethylenediaminetetraacetic acid (EDTA) followed by sodium chloride. Diaflo® ultrafilter membranes were used to separate solubilized membrane components into different molecular weight classes. The Rh(D) activity was demonstrated in the molecular weight class between 10 000 and 20 000. This fraction, which had six components by disc gel electrophoresis, was further purified by isoelectric focusing on a pH gradient of 3 to 10, followed by a pH gradient of 5 to 8. The Rh(D) antigen was eluted as a single component, migrated as a discrete band on disc gel electrophoresis, and inhibited the agglutination of anti-Rh(D) antibody. When the Rh(D) antigen was injected into guinea pigs, a high titer of anti-Rh(D) antibody was obtained.     

足月前胎膜早破的期待疗法

目的：探讨足月前胎膜早破期待疗法的可行性。方法：选取足月前胎膜早破病例102例，以为破膜1d内自发子宫收缩而分娩41例为对照组，破膜后行期待治疗3d内结束分娩32例为治疗1组，破膜后行期待治疗3d以上结束分娩29例为治疗2组，通过分析三组的分娩孕周、围生儿情况及产妇感染情况，综合判断期待疗法的效果。结果：期待治疗后围生儿的病死率、呼吸窘迫综合征率均有显著下降，而新生儿感染率及产妇感染率没有显著差异。结论：在严密监测和护理下期待治疗足月前胎膜旱破对改善存活儿的预后更具重要意义。     

A successful program of immunizing Rh-negative male volunteers for anti- D production using frozen/thawed blood

Individually matched (rhesus-D) Rh-positive frozen/thawed red blood cells were used to immunize 28 Rh-negative male volunteers. The immunizing schedule consisted of a single unit (200 ml) of frozen/thawed red blood cells, followed by six monthly booster doses (0.5 to 1.0 ml) after a rest period of six months. A final response rate of 93 percent (26 of 28) was achieved. All responders had produced anti-D before the second booster injection (mean detection time 4.25 months). Retrospective analysis indicated that the final response rate and the level of anti-D response could be predicted as early as seven to eight months from the start of immunization. These findings have practical implications for deciding when to discontinue immunization. The Rh genotype of the immunizing cells did not appear to be an important factor in determining the anti-D response, and with the matching system used, antibodies other than anti-C, D, and/or E were not produced. The use of frozen/thawed red blood cells for immunization has the advantage of permitting optimum matching for undesirable red blood cell antigens and minimizing the risk of transmitting disease to the recipients.     

97例新生儿窒息临床分析

目的探讨新生儿窒息的各种相关因素,制定预防措施,降低新生儿窒息率,提高产科质量。方法对97例新生儿窒息采取回顾性分析。结果新生儿窒息与多方面因素有关,胎膜早破、合并内科疾病、前置胎盘占新生儿窒息原因前三位。结论加强围产期保健,加强产前监护,及时治疗胎膜早破、妊高征等新生儿窒息高危因素,密切做好产时监护,及时处理异常产程,果断剖宫产终止妊娠,可降低新生儿窒息的发生率。     

Transforming growth factor-beta activity in sheep lung lymph during the development of pulmonary hypertension.

Chronic pulmonary hypertension is associated with extensive structural remodeling of the pulmonary arterial bed. The structural changes in the arterial walls include increased production of extracellular matrix components and smooth muscle cell hypertrophy, changes that have been similarly induced by transforming growth factor-beta (TGF-beta) in culture. In the present study, experiments were performed to determine whether TGF-beta is present in sheep lung lymph, and whether TGF-beta levels were altered in an animal model of chronic pulmonary hypertension induced by continuous air embolization. Several standard biological assays for TGF-beta activity were used for these determinations including soft agar assays, inhibition of epithelial cell proliferation, and a TGF-beta-specific radioreceptor assay. In each case, control lung lymph contained high concentrations of TGF-beta (100 ng/ml) which required transient acidification for detection. Samples of lung lymph from hypertensive sheep showed a transient and early two- to threefold increase in concentrations of latent TGF-beta. This activity could be partially blocked by TGF-beta antibodies. These studies indicate that sheep lung lymph contains TGF-beta and that the level of TGF-beta increases early during the development of pulmonary hypertension. Thus, TGF-beta may contribute to the development of the structural changes in the pulmonary arteries that occur during the onset of chronic pulmonary hypertension.