[Cardio-metabolic risk and adverse pregnancy outcomes in the first trimester: findings from the Shenzhen birth cohort study]

Objective: To investigate the relationship between cardio-metabolic abnormalities in the first trimester and adverse pregnancy outcomes (APO). Methods: This cohort study recruited singleton pregnancies in the first trimester (6-13+6 weeks of gestation) from Shenzhen Maternal and Child Health Care Hospital between January 1, 2021, and October 31, 2022. Cardiometabolic markers, including body mass index (BMI), blood pressure, fasting plasma glucose (FPG), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG), were recorded during the first trimester. Incidence of APO, including gestational hypertension, preeclampsia, gestational diabetes mellitus, preterm birth, fetal growth restriction, small for gestational age infant, and placental abruption, was documented. Cardiovascular metabolic abnormalities in the first trimester were defined as meeting one or more of the following criteria: elevated BMI (BMI≥24 kg/m²), elevated TG (TG≥1.7 mmol/L), decreased HDL-C (HDL-C<1.0 mmol/L), elevated blood pressure (systolic pressure≥130 mmHg (1 mmHg=0.133 kPa) and/or diastolic pressure≥85 mmHg), elevated FPG (FPG≥5.6 mmol/L). Enrolled women were categorized into abnormal cardio-metabolic and normal cardio-metabolic groups. Poisson regression was employed to analyze the association between cardio-metabolic abnormalities in the first trimester and APO. Results: The study included 14 197 pregnant women with an age of (32.0±4.1) years. There were 8 139 women in the normal cardio-metabolic group and 6 058 women in the abnormal cardio-metabolic group. Women with cardio-metabolic disorders in the first trimester had a younger gestational age and higher incidence rates of preterm birth, gestational hypertension, preeclampsia, and gestational diabetes mellitus (all P<0.05). In multivariable Poisson regression, elevated BMI (RR=1.22, 95%CI 1.15-1.29), elevated FPG (RR=1.59, 95%CI 1.38-1.82), elevated TG (RR=1.22, 95%CI 1.13-1.31), and elevated blood pressure (RR=1.50, 95%CI 1.39-1.63) were independent risk factors for APO, while decreased HDL-C (RR=0.93, 95%CI 0.70-1.23) was not. Elevated blood pressure (RR=5.57, 95%CI 4.58-6.78), elevated BMI (RR=1.71, 95%CI 1.40-2.09), and elevated TG (RR=1.38, 95%CI 1.10-1.74) had the greatest impact on the risk of developing preeclampsia. Elevated FPG (RR=1.70, 95%CI 1.45-1.99) had the greatest impact on the risk of gestational diabetes. Conclusions: Elevated blood pressure, BMI, TG and FPG in the first trimester are closely related to APO.

[Attach importance to prevention and effective interventions on child injury]

Injury is a threat to children globally and appears as the leading cause of death among children aged 1 to 17 years in China. Child injury prevention is a public health measure with a high cost-benefit ratio. Many years of research and practices have proved the effectiveness of specific child injury interventions. It is recommended that China should strengthen multi-sectoral cooperation and coordination mechanism on child injury prevention, including the clear clarification of responsibility and ensuring the necessary financial support. It is also essential to widely implement various effective interventions to ensure the healthy development of children.

[Occurrence of injuries among left-behind children from 27 poor rural areas in 12 provinces of China, 2016]

Objective: To understand the injuries among 16 459 left-behind children from 27 poor rural areas in 12 provinces of China, 2016. Methods: Data were collected from the survey of 'Health Service Needs Assessment' (HSNA) program on left-behind children, from poor rural areas in the middle and western parts of China. Factors including causes, types, locations, related activities, ways of treatment and outcomes among left-behind children with injuries in 2016, were described and analyzed by gender and age groups. Results: In 2016, per-person and person-time incidence rates of injuries were 8.88% and 11.21%, among the 16 459 left-behind children from 27 poor rural areas in 12 provinces of China, both higher in boys, than in girls. Most injuries were unintentional with its proportion higher in older children. The main types of injuries were seen as falls, blunt and sharp injuries, with burns and animal injuries more common in younger children. Injuries among left-behind children mainly took place at home, kindergarten/school, and on the highways/streets/roads, during playing. Most common ways of treatment would include at the emergency settings, self-treated, with older children more likely to treat by themselves. Most injuries were cured. Conclusions: In programs on prevention and control of injuries targeting the left-behind children in poor rural areas, special attention should be given to older boys, on falls and blunt/sharp injuries, at home or kindergarten/school. Education programs should pinpoint on self-rescue skills and guidance on kids by the parents, with behavioral norms and social support included. Related comprehensive prevention and control mechanism should be developed in families, schools and communities, with medical resources and insurance mechanism explored to serve these population and districts, including those left-behind children.

[Association of maternal nocturnal sleep throughout pregnancy with the early nocturnal sleep of infants]

Objective: To investigate the association between maternal nocturnal sleep during pregnancy and their infants' nocturnal sleep patterns in early infancy by establishing a birth cohort. Methods: In this prospective study,healthy pregnant women and their infants were recruited in Chongqing Health Center for Women and Children from September 2013 to January 2014. A total of 40 healthy pregnant women and their infants were enrolled, and 34 pairs (85%) completed the whole survey. Actiwatch, wearing on the mother's wrist or infant's ankle,was used to monitor nighttime sleep at home for 7 times in total,with 7 consecutive days for each monitoring course. Pregnant women were monitored at 16, 24, 32 weeks gestational age, and were required to finish Pittsburgh Sleep Quality Index (PSQI) scale at the end of each monitoring. Their infants were initially monitored at 14 days after birth, followed by 1(st), 2(nd), and 3(rd) month after birth,with sleep diary recorded by parents. Pearson correlation analysis and multivariate linear regression were used to investigate the potential correlation between these two sleep patterns. Results: The average nocturnal sleep time was (465±53) min throughout pregnancy, with increased trend in the latency of maternal nighttime sleep onset ((30±15), (34±29), (38±30) min) while decreasing of average sleep efficiency ((85±5)%, (84±8)%, (83±8)%). The longest night sleep duration decreased from (382±74) min in the first trimester to (330±83) min in the third trimester (F=4.932, P<0.05), while awakening time after sleep onset (WASO) correspondingly increased from (27±22) min to (53±25) min (F=12.605, P<0.05). In terms of infants, the latency of nighttime sleep onset decreased from (43±33) min on the 14th day to (20±29) min at 3-month of age (t=3.281, P=0.002), while the longest nighttime sleep duration increased from (20±62) min to (265±140) min (t=3.867, P<0.01); meanwhile, the total nocturnal sleep time and the sleep efficiency increased from (373±126) min and (63±28)% to (431±103) min and (75±16)%, respectively (t=2.362, P=0.024; t=2.418, P=0.039, respectively). After adjusting for maternal age and body mass index (BMI), parental educational level and family income, maternal mood, exposure to tobacco and alcohol during pregnancy, method of delivery, as well as infants' gender, feeding patterns and gestational weeks, the regression analysis showed that the total nocturnal sleep time and the longest nighttime sleep duration during pregnancy were positively correlated with the corresponding parameters of their infants at the age of 3 months (B=0.541, 95%CI 0.168-0.914, t=2.882, P=0.005; B=0.310, 95%CI 0.035-0.586, t=2.240, P=0.027, respectively). Conclusions: The total nocturnal sleep time and the longest nighttime sleep duration during pregnancy are positively correlated with the corresponding parameters of their infants in early infancy. Paying more attention to improve maternal sleep quality may facilitate their infants to establish sleep-wake patterns early.

[Effectiveness of integrated early childhood development intervention on nurturing care for children aged 0-35 months in rural China]

Objective: To explore whether Integrated Early Childhood Development (IECD) program has effectively improved the nurturing care for children aged 0-35 months in rural China. Methods: IECD has been implemented by the government of China with support from the United Nations Children's Fund (UNICEF) in four poverty-stricken rural counties since 2014. The interventions targeting the five key components of nurturing care (i.e. child and caregiver health, child nutrition, early learning support, child protection and social security) were delivered through the IECD program to children aged 0 to 35 months and their caregivers. A population-based intervention trial was designed to evaluate intervention effectiveness with data collected in 2013 (baseline) and 2016 (mid-term). The changes of nurturing care in the intervention and control group were analyzed by using a difference-in-differences (DID) model. This approach provided adjustment for sociodemographic and other confounding factors. Results: The baseline and mid-term survey enrolled 1 468 and 1 384 children in the intervention group, and 1 485 and 1 361 in the control group. After two years of implementation, the prevalence of caregiver's depression in the intervention group showed a decrease of 9.1% (mid-term 34.8% (479/1 377) vs. baseline 43.9% (621/1 414)), whereas that in control group showed a decrease of 1.6% (mid-term 34.3% (464/1 353) vs. baseline 35.9% (509/1 419)). With the confounding adjusted in the difference-in-differences model, the decrease of the caregiver's depression prevalence in the intervention group was 7.0% greater than that in the control group (P=0.008). The qualified rate of minimum meal frequency in the intervention group showed an increase of 10.4% (mid-term 69.0% (532/771) vs. baseline 58.6% (481/821)), whereas the qualified rate in the intervention group showed an increase of 2.9% (mid-term 66.4% (469/706) vs. baseline 63.5% (508/800)). With the confounding adjusted in the difference-in-differences model, the increase of the qualified rate in the intervention group was 8.2% greater than that in the control group (P=0.021). The proportion of violent discipline by caregivers in the intervention group showed a decrease of 6.2% (mid-term 49.1% (478/973) vs. baseline 55.3% (554/1 001)), whereas the proportion in control group showed an increase of 4.5% (mid-term 58.4% (560/959) vs. baseline 53.9% (558/1 036)), and with the confounding adjusted in the difference-in-differences model, the difference in increase rate between two groups was 11.0% (P=0.001). The proportion of families with three or more children's books in the intervention group showed an increase of 12.7% (mid-term 42.7% (588/1 378) vs. baseline 30.0% (432/1 440)), whereas the proportion of the control group showed an increase of 4.2% (mid-term 25.7% (349/1 357) vs. baseline 21.5% (298/1 388)), and with the confounding adjusted in the difference-in-differences model, the difference in increase rate between two groups was 6.1% (P=0.007). Conclusions: The IECD intervention strategy implemented in rural China effectively improved the mental health of caregivers, optimizes families' child feeding and early stimulation behaviors, while reducing violent discipline and other risk factors. IECD provides better nurturing care for the early development of children aged 0-35 months in rural China.

Simple conversion of earth-abundant coal to high-performance bifunctional catalysts for reversible oxygen electrodes

Efficient bifunctional electrocatalysts for reversible oxygen electrodes are vitally important for the realization of important future generation electrochemical energy conversion devices, such as regenerative fuel cells and rechargeable metal–air batteries.

[Percentile curves on growth among breastfed 1-4 year olds in 8 urban areas]

Objective: To construct the growth percentile curves of weight-, length/height-, head circumference and BMI for 1 to 4 year-olds who had been breastfed in urban areas. Methods: Data was from the longitudinal study on 1 025 breastfed children aged 1 to 4 years, in 8 urban areas during 2008-2012. MLwiN2.25 was selected to construct the multi-level models of weight-for-age,length for-age, head circumference-for-age and BMI-for-age. The models included many growth relevant factors including gender, age, family and social demographic characteristics, perinatal factors, parent biological characteristics, dietary patterns and diseases of childen. Based on these models, predicted values (P(3), P(15), P(50), P(85), P(97)) were estimated to fit the percentiles reference curves. Results: The percentiles reference curves of weight-, length/height, head circumferenceand BMI-for-age for the 1-4 year-olds who had been breastfed in the urban areas were developed. Differences of all the indicators between boys and girls were statistically significant (P<0.001). Weight, length/height, head circumference and BMI were higher in boys than those in girls, with an average differences as 0.56-0.76 kg, 0.89-1.12 cm, 0.64-0.91 cm and 0.31-0.52 kg/m(2). Conclusion: The percentiles reference curves on growth, constructed by the longitudinal observational data and scientific method, were important in reflecting the development of breastfed children in urban areas.

The effects of fasudil on the permeability of the rat blood-brain barrier and blood-spinal cord barrier following experimental autoimmune encephalomyelitis

Dysfunction of the blood-brain barrier (BBB) and blood-spinal cord barrier (BSCB) is a primary characteristic of multiple sclerosis (MS). We evaluated the protective effects of fasudil, a selective ROCK inhibitor, in a model of experimental autoimmune encephalomyelitis (EAE) that was induced by guinea-pig spinal cord. In addition, we studied the effects of fasudil on BBB and BSCB permeability. We found that fasudil partly alleviated EAE-dependent damage by decreasing BBB and BSCB permeability. These results provide rationale for the development of selective inhibitors of Rho kinase as a novel therapy for MS.

Protective effect and mechanism of Ginkgo biloba leaf extracts for Parkinson disease induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine

AIM

To observe the effects of extracts of Ginkgo biloba leaves (EGb) on the Parkinson disease (PD) models induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its ion 1-methyl-4-phenylpyridinium (MPP+).

METHODS

MPTP was microinjected into substantia nigra of rats to induce a behavior change of rotation. EGb (ip, 50 or 100 mg.kg(1 . d-1) was pretreated consecutively for 19 d before MPTP administered and 1 d after MPTP administered. The contents of malondialdehyde (MDA), superoxide dismutase (SOD), and dopamine (DA) in substantia nigra of model rats were determined. Apoptosis of PC12 cells was induced by MPP+, and the protective effect of EGb (25, 50, and 100 mg/L) was also observed. The cells of apoptosis were observed under a microscope and counted under a fluoroscope after stained with AO/EB.

RESULTS

EGb (100 mg . kg-1 . d-1) decreased the duration and frequency of the rotation of rats (P < 0.05, n = 10 ) while EGb (50 or 100 mg/L)inhibited the decreases of DA and SOD and the increase of MDA induced by MPTP, (P < 0.05 or P < 0.01, n = 10). MPP+ (10 micromol/L) induced the apoptosis of PC12 cells, and EGb (50 or 100 mg/L) prevented cells from apoptosis at 6 h, 12 h, and 24 h (P < 0.05 or P < 0.01, n = 3).

CONCLUSION

EGb possesses protective effect on the PD models in vivo and in vitro. The anti-oxidation and anti-apoptosis may be one of the mechanisms underlying the neuroprotective effect of EGb.

[RP-HPLC method for determination of protopine in plasma and pharmacokinetics in rats]

AIM

To develop a reversed phase high performance liquid chromatographic method (RP-HPLC) for determination of protopine (Pro) in rat plasma and to investigate the pharmacokinetics of Pro in rats.

METHODS

The column was packed with 5 microns C18. The mobile phase (pH 5.6) was a mixture of methanol-water-10% acetic acid (80:20:2). After twice extracted with ether under basic condition, and reextracted with 0.02 mol.L-1 sulfuric acid, protopine in the plasma samples was isolated well. The content of protopine in the plasma sample was measured by UV detector at 285 nm.

RESULTS

The lowest limit of detection was 50 ng.mL-1. The intraday and interday precisions were 1.5%-3.0% and 2.1%-6.2%, respectively. The mean recovery was 80.6%-97.6%. A good linear relationship between the peak height and the concentration of protopine in rat plasma was observed. The pharmacokinetics of protopine had been investigated in rats after intravenous administration 10 mg.kg-1. The concentration-time curve of protopine in rat was confirmed to two-compartment open model. The T1/2 alpha, T1/2 beta, Ke, CL, Vd were 0.05 h, 1.85 h, 1.52 h, 6.41 L.h-1 and 17.27 L, respectively.

CONCLUSION

This method is suitable for studies on pharmacokinetics of protopine.

Trauma and alkali burns induce distinct patterns of cytokine gene expression in the rat cornea

Cytokines such as the interleukins (IL) and tumor necrosis factor alpha (TNF alpha) have traditionally been associated with paracrine regulation of immune reactions. These proteins also have properties suggestive of functional roles in the inflammatory and reparative responses to tissue injury. In this study, mRNA levels for IL-1 alpha, IL-1 beta, IL-6, TNF alpha, interferon gamma, transforming growth factor beta 1, and CD4 were monitored in rat corneas at times from 1 hour through 2 weeks after incisional trauma or alkali burns. Transcripts for IL-1 alpha, TNF alpha, and TGF beta 1 were present in most corneal samples; whereas those for IFN gamma and CD4 were not detected. As early as 1 hour following either of these non-immunologic forms of injury, expression of IL-6 mRNA levels was induced. Only in corneas with alkali burns did IL-6 induction persist from days 1 through 7. The alkali-injured corneas also had markedly increased IL-1 beta mRNA levels from days 1 through 7. These observations indicate that cytokine mRNA is induced in the cornea by trauma without an apparent immunologic stimulus. Our data are consistent with the hypothesis that corneal tissues respond to different types of injury with different patterns of cytokine gene expression.

Mast cells are a major source of basic fibroblast growth factor in chronic inflammation and cutaneous hemangioma

Mast cells play an essential role during development of inflammation after chemical and immunological insults and have been implicated in tissue fibrosis and angiogenesis. The exact contribution of mast cells to these conditions is largely unknown. In this study, we found that a potent angiogenic and mitogenic polypeptide, basic fibroblast growth factor (bFGF), is localized to the majority of mast cells from normal skin and lung and in tissue samples characterized by fibrosis, hyperplasia, and neovascularization. Using specific antibodies to mast cell tryptase, tissue macrophage, and bFGF, we demonstrate that cytoplasmic bFGF immunoreactivity is localized to 96.8 +/- 9.6% of tryptase-positive cells in human fibrotic lung tissue (n = 10), 82.3 +/- 6.9% of tryptase-positive cells in rheumatoid synovia (n = 6), and 93.1 +/- 4.8% of tryptase-positive cells in skin hemangioma (n = 5). Moreover, these tryptase-positive cells comprise a major portion (86 to 97%) of nonvascular cells exhibiting cytoplasmic bFGF staining in these tissues. In contrast, macrophage-like cells contribute less than 10% of the bFGF-positive cells in the same samples. The specificity of the immunostaining results was supported by the finding that cultured human mast cells (HMC-1) express both bFGF mRNA and protein. Our data indicate that mast cells, a primary source of heparin, also serve as a significant source of a heparin-binding growth factor, bFGF, in these disease processes. These observations suggest that mast cells may contribute to these pathological conditions by releasing this polypeptide.

Expression of basic fibroblast growth factor in synovial tissue from patients with rheumatoid arthritis and degenerative joint disease

BACKGROUND

Recent studies have implicated polypeptide growth factors in the development of rheumatoid arthritis (RA), which is characterized by synoviocyte hyperplasia and neovascularization. One such polypeptide, basic fibroblast growth factor (bFGF), is of particular interest because of its potent mitogenic and angiogenic activities. We have previously reported that cultured human synoviocytes synthesize and bind bFGF and also proliferate in response to it (1). Recently, we found a close association between increased bFGF expression and destructive changes in arthritic joints from rats (2). Now we extend our study by detecting in vivo expression of bFGF in human synovial tissues obtained from patients with RA.

EXPERIMENTAL DESIGN

Human synovial tissues from patients with RA, degenerative joint disease (DJD), and trauma were collected during joint surgery. The expression of bFGF protein and mRNA by the synovia was examined by immunolocalization, Western blot, Northern blot, and RNase protection assays. Synovium from patients with DJD and trauma was used to compare with rheumatoid synovium. Double immunostaining with cell type-specific antibodies was carried out to identify cellular sources of bFGF.

RESULTS

Both polypeptide and mRNA for bFGF were detected in the synovial samples examined. Increased bFGF staining was found in synovium-cartilage interface where joint destruction occurred and in hyperplastic synoviocytes of a subset of rheumatoid synovium. Strong cytoplasmic bFGF staining was localized in the majority of mast cells and vascular cells.

CONCLUSIONS

Synovial tissue from patients with RA, DJD, and trauma express bFGF. Increased bFGF staining in the hyperplastic lining synoviocytes and at the pannus-cartilage interface suggests that bFGF may play a role in synovial hyperplasia and joint destruction. Strong cytoplasmic bFGF staining found in mast cells and vascular cells indicates that these cells are the major sources of tissue bFGF.

Detection of mRNA for the cytokines, interleukin-1 alpha and interleukin-8, in corneas from patients with pseudophakic bullous keratopathy

PURPOSE

Cytokines have been implicated in corneal inflammatory diseases. The authors sought to determine if corneal diseases with different patterns of inflammation are accompanied by characteristic patterns of cytokine expression.

METHODS

The authors used reverse transcription-polymerase chain reaction to detect mRNA for 12 specific cytokines from patients with Fuch's dystrophy (n = 7), pseudophakic bullous keratopathy (n = 12), or normal corneas (n = 4).

RESULTS

Using Wilcoxon rank sum analysis, mRNA for interleukin (IL)-1 alpha or IL-8 was significantly more abundant in corneas from patients with pseudophakic bullous keratopathy relative to either comparison group. mRNA for the T-cell marker, CD4, and for T-cell derived cytokines, IL-2, IL-4, and interferon gamma, could not be detected in any corneal sample. Message for IL-1 receptor antagonist and transforming growth factor-beta 1 or -beta 2 was readily detectable in most corneas regardless of diagnosis.

CONCLUSION

The findings indicate that the pattern of cytokine mRNA expression reflects differences in the pathogenesis of these corneal diseases.

Cytokine mRNA levels in rat ocular tissues after systemic endotoxin treatment

PURPOSE

An intertwined cascading network of cytokines is believed to direct the development of endotoxin-induced uveitis (EIU). This study investigated mRNA levels of interleukin (IL) 1 alpha, IL-1 beta, IL-6, tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, transforming growth factor (TGF)-beta 1, and the helper T lymphocyte marker, CD4, during the course of EIU in rats.

METHODS

Reverse transcription followed by polymerase chain reaction amplification was used to determine relative mRNA levels in four ocular tissues (iris/ciliary body, cornea, lens, and neuroretina) at 0, 1, 3, 6, 24, and 48 hours after subcutaneous injection of 200 micrograms of Escherichia coli endotoxin.

RESULTS

Four general patterns of mRNA expression were observed: (1) constitutively expressed and unaffected by endotoxin; (2) constitutively expressed but further induced by endotoxin, reaching peak levels at 3 hours postinjection; (3) initially undetectable or marginally detectable and induced by endotoxin, with peak levels occurring 3 hours postinjection; and (4) never present at appreciable levels. The most dramatic responses were seen in the mRNA levels of IL-1 alpha, IL-1 beta, IL-6, TNF-alpha, and IFN-gamma in iris/ciliary body. Lesser mRNA level responses were found for IL-1 beta and IL-6 in cornea and for IL-1 alpha, IL-1 beta, IL-6, TNF-alpha, and IFN-gamma in neuroretina. Little or no changes in mRNA levels were observed for CD4 or TGF-beta 1 in any tissue or for any mRNA examined in lens.

CONCLUSIONS

These data show that subcutaneous endotoxin induces cytokine mRNA expression differentially in ocular tissues. These data support the hypothesis that induction of cytokine expression in iris/ciliary body plays a major role in the development of EIU.

Retinal pigment epithelial cells produce interleukin-1 beta and granulocyte-macrophage colony-stimulating factor in response to interleukin-1 alpha

The retinal pigment epithelium (RPE) is clinically involved in diverse ocular inflammatory diseases. Because perturbed RPE cells produce a variety of inflammatory substances, RPE cells may play an integral part in these diseases. Interleukin-1 (IL-1) and granulocyte-macrophage colony-stimulating factor (GM-CSF) are pleiotropic cytokines with the ability to trigger numerous inflammatory responses. This report shows that cultured human RPE cells synthesize interleukin-1 beta (IL-1 beta) and GM-CSF in response to the potentially inflammatory cytokine, IL-1 alpha, but not to E. coli endotoxin. Control RPE cells made little or no mRNA or protein for either IL-1 beta or GM-CSF. Upon stimulation of the cells by IL-1 alpha, both IL-1 beta and GM-CSF mRNAs were readily apparent by 3 hours, persisted for over 24 hours, and were translated into immunologically detectable proteins. GM-CSF protein was secreted into the culture medium, whereas IL-1 beta protein remained cell associated. The IL-1 alpha-induced mRNA and protein production were inhibited by dexamethasone. These observations provide additional evidence that RPE cells are capable of playing a pivotal role during ocular inflammation.

Expression of growth factor mRNA in rabbit PVR model systems

Proliferative vitreoretinopathy (PVR) involves the formation of intravitreal fibrocellular membranes which may lead to traction retinal detachment and blindness. The cellular component of epiretinal membranes originates from the proliferation and migration of cells within the eye. Several growth factors and other cytokines are plausible candidates for directing the processes leading to membrane formation. A reproducible animal model is needed for experimental studies of cytokine expression during PVR induction or treatment. We found that intravitreal injection of > 10(6) mixed mononuclear leukocytes or adherent monocytes along with a trans-scleral incision through the pars plana leads to the development of PVR-like disease in rabbit eyes. The severity of the disease was related to the number of monocytes injected. Typically, organized membranes extending from the incision toward the optic nerve formed within one week. Progression to extensive traction retinal detachment required 1 to 4 weeks. Injection of up to 5 x 10(6) lymphocytes or freeze-thaw killed monocytes was ineffective, and coinjecting 100 micrograms endotoxin with the monocytes did not result in enhanced disease. The histological appearance of the epiretinal membranes was similar to human PVR membranes. Macrophage, cytokeratin-positive (epithelial), and fibroblast-like cells were present. Northern blot analysis of RNA extracted from the rabbit membranes revealed the presence of mRNA for acidic fibroblast growth factor (aFGF). Acidic FGF mRNA was not expressed by the injected monocytes. A comparable level of aFGF mRNA and also mRNAs for basic FGF, platelet-derived growth factor-B, and transforming growth factor beta were found in epiretinal membranes induced by a scleral incision in association with cryopexy.(ABSTRACT TRUNCATED AT 250 WORDS)

Ca2(+)-dependence of endothelin-1 induced contraction of rat tail artery

1. In rat tail artery, endothelin-1(ET-1) caused an increase in the cytosolic free Ca2+ level ([Ca2+]i) followed by a relatively sustained but not steady-state contraction in Ca2+ containing solution. 2. In the early phase of the contraction, the rate of increase in [Ca2+]i, was much faster than that in muscle tension. However, after the increases in [Ca2+]i and muscle tension reached at their peaks, there was a good correlation between the changes of the two parameters. 3. ET-1 could not induce an apparent contractile response in Ca2(+)-free medium, notwithstanding it evoked a [Ca2+]i transient in this medium. 4. The results indicate that ET-1 induce a contraction of rat tail artery which is almost fully dependent on the [Ca2+]i changes, and may inhibit the Ca2(+)-sensitivity of the contractile filaments in the early phase of the contraction.

Endothelin-1 induced contraction of rat aorta in Ca2(+)-free medium independent of phosphatidylinositol 4,5-bisphosphate (PIP2) breakdown

1. The mechanism of endothelin-1 (ET)-induced contraction of rat aorta in Ca2(+)-free medium was investigated and compared with that of phenylephrine-induced contraction, measuring tension development and inositol 1,4,5-trisphosphate (IP3) formation. 2. After Ca2(+)-deprivation for 10 min, ET (10 nM) induced only a slow sustained contraction, whereas phenylephrine (10 microM) evoked a rapid phasic contraction followed by a small sustained one. Prolonged incubation of the strips in Ca2(+)-free medium (for 100 min) abolished the phasic contraction evoked by phenylephrine, but had no effect on the sustained contraction by either stimulant. 3. ET (100 nM) and phenylephrine (10 microM) stimulated inositol trisphosphate formation and these effects were inhibited by TPA (5 microM). 4. TPA (5 microM) had no effect on ET (10 nM)-induced contraction in Ca2(+)-free medium, but inhibited the contraction by phenylephrine (10 microM). 5. The ET- and phenylephrine-induced contractions in Ca2(+)-free PSS were inhibited by H-7, a protein kinase C inhibitor. 6. The difference and similarity of signal transduction pathways between alpha 1-adrenoceptor and ET receptor systems were discussed.

Endothelin-1 induced contraction of rat aorta: contributions made by Ca2+ influx and activation of contractile apparatus associated with no change in cytoplasmic Ca2+ level

The modes by which endothelin-1 (ET) induces Ca2(+)-influx and the relative functional importance of the different sources of Ca2+ for ET-induced contraction were studied using fura 2-loaded and unloaded rat aortic strips. ET caused an increase in the cytosolic free Ca2+ level ([Ca2+]i) followed by a tonic contraction in Ca2(+)-containing solution, and produced a transient elevation of [Ca2+]i followed by a small sustained contraction in Ca2(+)-free medium. ET also stimulated 45Ca influx into La3(+)-inaccessible fraction significantly. With the same change of [Ca2+]i, ET caused a larger tension than that induced by high K. ET-induced contraction and [Ca2+]i elevation were not significantly inhibited by 0.1-0.3 microM nicardipine which nearly abolished the contraction and [Ca2+]i elevation produced by high K. During treatment of the strips with high K, addition of ET induced further increases in [Ca2+]i and muscle tension, and vice versa. In Ca2(+)-free medium, ET-induced contraction was influenced neither by ryanodine-treatment nor by high K-treatment, although the former attenuated and the latter potentiated the [Ca2+]i transient induced by ET. Further, the ET-induced sustained contraction under Ca2(+)-free conditions began to develop after the [Ca2+]i level returned to the baseline. Thus, it seems that the Ca2+ released from the ryanodine-sensitive and -insensitive Ca2+ stores by ET may provide only a minor or indirect contribution, if any, to the tension development. ET might cause a contraction mainly by stimulating Ca2(+)-influx through Ca2+ channel(s) other than voltage-dependent Ca2+ channels in character, and by increasing the sensitivity of the contractile filaments to Ca2+ or activating them Ca2(+)-independently.