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Query: UMLS:C0728731 (prematurity)
 7,134 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several diseases of prematurity are thought to be related to oxidative injury and many of the available markers are unsatisfactory. An assay was developed using HPLC with electrochemical detection for the quantitation of urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) as a proposed indicator for oxygen-derived free radical injury to DNA in preterm infants. A median value of 3.79 micromol/mol creatinine was obtained for normal children (2-15 years old, n=14). Urinary 8-OHdG excretion in neonates ranged from 0-99 micromol/mol creatinine. There were no gestation or birthweight related differences in urinary 8-OHdG, and no correlation with urinary malondialdehyde. Mean 8-OHdG excretion increased with postnatal age (r=0.80, p < 0.0001, n=15), mirroring the growth velocity curve. These changes could also be due to changes in the activity of the enzyme responsible for 8-OHdG excision. Urinary 8-OHdG levels are unlikely to accurately reflect oxygen derived free radical activity given the strength of the relationship with growth.
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PMID:Urinary 8-hydroxydeoxyguanosine in infants and children. 968 87

The outlook of pregnancy for women with lupus nephritis is usually favourable if the disease has been quiescent for at least 3 months before pregnancy, and if, at conception, serum creatinine is less than 140 mumol/l, proteinuria less than 3 grams/25 hours and blood pressure controlled. The risk of fetal loss is, however, 2-3 times higher than in the normal population and pre-eclampsia, prematurity and fetal growth retardation frequently complicate these pregnancies. Pregnancies in women with lupus nephritis are high-risk pregnancies and they require intense fetal and maternal surveillance.
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PMID:Renal lupus in pregnancy. 975 40

Female solid organ recipients with good graft function generally tolerate pregnancy well. However, the combination of mother, fetus, transplanted organ, and immunosuppressive and other medications increases the complexity of management and raises the specter of adverse outcomes. For the mother, considerations include the nature of the original disease (i.e. genetic risk of transmission), co-morbid conditions which increase pregnancy risk (i.e. hypertension, diabetes, renal insufficiency), and long-term maternal prognosis. For the fetus, questions include the adequacy of maternal physiology (cardiac, renal, glycernic control, etc.), exposure to medications, and exposure to infectious agents. The transplanted organ must accommodate the increased workload of pregnancy and the needs of the fetus. The delicate balance between immunosuppression and rejection may be altered by the pregnancy. The impact of pregnancy on recurrent disease can also be an issue. Medication issues include changes in drug pharmacokinetics and the potential for adverse effects on the fetus. These effects could include chromosomal aberrations, structural malformations, organ-specific toxicity, intrauterine growth retardation, and immune system development. For female kidney recipients there are sufficient data to demonstrate a direct relationship between creatinine levels before and during pregnancy and risk of graft loss in the postpartum period. Pregnancy itself does not appear to adversely affect stable graft function. Among liver recipients, those with recurrent viral hepatitis may have deterioration of graft function with subsequent pregnancies. These recipients should be apprised accordingly, as maternal deaths have occurred in this setting. Postpartum depression and potential for medication noncompliance require vigilance. The safety of pregnancy from the NTPR analysis to date has been largely derived from the experience with CsA-based regimens. For recipients on CsA there have been good maternal outcomes without any specific or predominant malformation patterns in the offspring. For the general population, malformations occur in approximately 3% of live births. To date, there is no indication that this incidence has increased despite the complex medical regimens of transplant recipients. Data are accruing with tacrolimus and Neoral. Continuing data entry and continued follow-up of off-spring will allow for further recommendations, especially in light of the new medications and combinations. Recipients should be advised to wait one to 2 years after transplant before considering pregnancy. Those with stable graft function, and with no rejection, graft dysfunction, or deterioration should still be apprised of the high risk of prematurity and low birthweight, although maternal risks appear low. These are high-risk pregnancies, requiring close communication and cooperation between the high-risk obstetrician and the transplant team. The use of the FDA pregnancy categories should not be the sole reason for choosing a particular immunosuppressive drug. Agents such as Neoral and tacrolimus would appear to offer some advantage as blood levels can be measured. At present, no safety guidelines can be given for mycophenolate mofetil, OKT3, or ATG. Identification of prepregnancy factors predictive of higher risks and appropriate counseling and management guidelines are major NTPR goals, and depend on the continued assistance and cooperation of the transplant community.
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PMID:Report from the National Transplantation Pregnancy Registry (NTPR): outcomes of pregnancy after transplantation. 991 94

Childbearing is important to women with renal disease, but pregnancy has generally been regarded as very high risk in these women. In this review, an attempt is made to clarify the nature and severity of those risks in the settings of chronic renal insufficiency and end-stage renal disease, including dialysis patients and transplant recipients. Hypertension is the most common life-threatening problem in all three groups. A wide range of antihypertensive medications have been used, with angiotensin-converting enzyme inhibitors the only drugs absolutely contraindicated because of their association with neonatal anuria, pulmonary hypoplasia, and neonatal death. Women with serum creatinine levels of 1.4 mg/dL or greater are at risk for accelerated loss of renal function compared with women who don't become pregnant. Transplant recipients have a risk for loss of renal function similar to controls as long as renal function is well preserved. The frequency of conception is decreased in women with renal insufficiency and markedly decreased in dialysis patients (0.5% per year). Return of fertility is the rule in transplant recipients. Exposure to immunosuppressive drugs, including prednisone, azathioprine, cyclosporine, and tacrolimus, has not been associated with an increase in congenital anomalies. These drugs, particularly cyclosporine, have been associated with small-for-gestational-age babies. Transplant recipients are at risk for infections that have implications for the fetus, including cytomegalovirus, herpes simplex, and toxoplasmosis. All groups have an increased risk for prematurity and intrauterine growth restriction. The percentage of pregnancies resulting in surviving infants in women with renal insufficiency and transplant recipients ranges from 70% to 100%. For women who conceive after starting dialysis, the likelihood of a surviving infant is approximately 50%.
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PMID:Pregnancy in chronic renal insufficiency and end-stage renal disease. 1002 34

To assess the impact of prematurity-associated nephrocalcinosis on kidney function later in life, 20 premature children with neonatal nephrocalcinosis and 20 controls, matched for birth weight and postnatal age but without nephrocalcinosis, were examined (birth weight 905+/-209 vs. 957+/-226 g; study age 4.7+/-1.1 vs. 4.6+/-0.9 years). Distal tubular acidification capacity was measured with the oral acetazolamide test, in which the response was abnormal in 1 out of the 20 children with a history of nephrocalcinosis, but in none of the controls. Urinary calcium and beta(2)-microglobulin excretion were higher in the children with nephrocalcinosis, but no differences were found in fractional excretion of sodium and potassium or tubular reabsorption of phosphate. Estimated creatinine clearance was not different between the groups. Of the 6 children with nephrocalcinosis lasting beyond 2 years of age, 5 had had chronic lung disease neonatally and exhibited a tendency for compensated respiratory acidosis at the time of the examination. Neonatal nephrocalcinosis seems to lead to some signs of renal tubular dysfunction in early childhood of preterm infants. Glomerular function, however, appears not to be specifically disturbed by nephrocalcinosis.
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PMID:Prematurity-associated nephrocalcinosis and kidney function in early childhood. 1060 42

Specific data on pregnancies following transplantation continue to accrue in the National Transplantation Pregnancy Registry (NTPR) in each type of organ recipient, with the following conclusions: 1. While the majority of kidney recipients appear to tolerate pregnancy well, a small percentage develops rejection, graft dysfunction and/or graft deterioration. Overall, there is a slight increase in the mean postpartum creatinine level when compared with the prepregnancy level, which has been noted in previous investigations by the NTPR. One neonatal death attributed to thrombotic cardiomyopathy was noted in a set of twins of a tacrolimus-based kidney recipient, but no other death has been noted in any of the additional reports among the recipients given newer immunosuppression regimens. Follow-up of offspring of these recipients is ongoing. 2. No structural malformations have been noted among offspring exposed to mycophenolate mofetil, but exposures are limited. (5 mothers, 29 fathers). 3. Female liver recipients with biopsy-proven acute rejection during pregnancy appear to be at greater risk for both poorer newborn outcomes and recurrent rejection episodes. In the setting of acute rejection diagnosed during pregnancy, close attention is warranted, anticipating that birthweight may be lower and that a substantial percentage of these female recipients may have recurrent rejection episodes. 4. Pancreas-kidney grafts can maintain normoglycemia throughout pregnancy. A high incidence of maternal hypertension, prematurity and low birthweight have been noted, so, as in other recipient groups, these are high-risk pregnancies. Maternal pancreas and kidney function must be closely monitored. 5. No specific prepregnancy predictors of adverse outcomes have yet been identified among heart or lung recipients although none of the deaths among heart recipients in the NTPR database occurred within 2 years of delivery. When compared with other solid organ recipients, female lung recipients may face higher risks, particularly related to rejection. Whether prepregnancy factors can help to predict either heart or lung recipients at risk requires continued study. 6. No structural malformations or significant learning disabilities have been noted in follow-up of the offspring of CsA-treated females, the largest group of offspring followed to date with a mean age of 4-5 years. Continued surveillance of children will be essential to determine if effects become apparent as age-related developmental delays or other problems in immune function or fertility later in life. 7. Newer regimens as well as new combinations of agents will continue to be studied. It is essential that non-viable as well as viable pregnancy outcomes be reported to the registry (i.e., recipients with pregnancies that result in spontaneous abortion or termination should be included for study). True estimates of non-viable outcomes have been difficult to assess. Additionally, inclusion of reports of pathologic evaluations at delivery hospitals will be helpful to determine whether spontaneous abortions are a result of lethal malformations related to immunosuppressive or other medication exposure. Safety of pregnancy for parent and child remain the primary goals of the NTPR.
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PMID:Report from the National Transplantation Pregnancy Registry (NTPR): outcomes of pregnancy after transplantation. 1103 29

The purpose of this study was to describe the maturation of vancomycin (V) clearance and the influence of altered renal function in infants on vancomycin using population pharmacokinetic methods. A population pharmacokinetic model was developed using NONMEM from clinical data obtained from 374 newborns and infants < 2 years of age (median age = 27 days) from four institutions. A total of 1103 serum V concentrations were used in the model development, including 311 with elevated serum creatinine (CR) (> 0.8 mg/dl) and more than 104 evaluations in infants older than 2 months of age. The final model was evaluated against a second data set of 160 concentrations from 67 infants at one of the institutions and then used to develop dosing guidelines. The data were best described by a two-compartment model. Weight and CR greatly influenced vancomycin elimination, while postnatal age and prematurity (< 28 weeks) were significant but less important predictors of V elimination. For the typical study infant (age = 27 days, CR = 0.6, WT= 1.8 kg, gestational age = 33.5 weeks), this results in VdSS = 0.79 l/kg and Cl = 0.066 l/h/kg. The validation data set showed the model to be unbiased. Dosing guidelines from this model, based on serum creatinine and gestational age at birth, performed better than published guidelines based on postconceptional age. Vancomycin clearance is initially reduced in premature infants and increases with postnatal age. Most of the age-related changes could be predicted by the concomitant fall in serum creatinine. Dosing guidelines that incorporate these factors are more likely to produce therapeutic V concentrations in infants.
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PMID:The influences of renal function and maturation on vancomycin elimination in newborns and infants. 1154 96

Family planning and pregnancy are important and usually problematic issues for a young woman with lupus nephritis. Moderate renal insufficiency and previous use of alkylating cytotoxic drugs are associated with decreased fertility. Oral contraceptives containing synthetic estrogens are contraindicated in women with active lupus nephritis, uncontrolled hypertension, history of thromboembolic diseases or high levels of antiphospholipid antibodies. Mild flares of systemic lupus erythematosus (SLE) are common during pregnancy, severe renal flares and permanent impairment of renal function are uncommon. The outlook of pregnancy for women with lupus nephritis is usually favourable if the disease (both renal and nonrenal) has been quiescent for at least 6 months before pregnancy, and if, at conception, serum creatinine is less than 140 micromol/l, proteinuria less than 3 g/24 h and blood pressure controlled. The risk of fetal loss is, however, at least 2-3 times higher than in the normal population and pre-eclampsia, prematurity and fetal growth retardation frequently complicate these pregnancies. Especially poor fetal outcome is associated with antiphospholipid antibodies. Pregnancies in women with lupus nephritis require intense fetal and maternal surveillance.
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PMID:Pregnancy and lupus nephritis. 1167 60

Very low birth weight (VLBW) infants can be subjected to oxidative stress in the course of intensive care. We measured 8-hydroxydeoxyguanosine (8-OHdG), a biomarker of oxidative stress, and estimated the degree of oxidative stress in such infants. We also examined if the administered oxygen was related to oxidative stress. Urine samples of 50 Japanese VLBW infants [birth weights: 956.3+/-277.6g, and gestational ages: 28.0+/-2.6 weeks (mean +/- SD)] were collected on various postnatal days and 8-OHdG levels were determined using an ELISA kit. Sixteen term infants served as normal controls. As body weights at sampling increased, the average levels of urinary 8-OHdG decreased. 8-Hydroxydeoxyguanosine levels were: infants under 1000g, 29.5+/-16.4 micromol/mol creatinine (n = 24); 1000-1500g, 23.8+/-14.9 (n = 12); over 1500g, 16.1+/-8.5 (n = 14); and control, 10.9+/-7.2 (n = 16). Significant differences were found between <1000g group and > or = 1500g group (p = 0.0030), <1000g group and control (p < 0.0001), and 1000-1500g group and control (p = 0.0108). Also as postconceptional age at sampling increased, the average levels of 8-OHdG decreased. 8-Hydroxydeoxyguanosine levels were: infants before 252 days (36 weeks) of postconception: 27.4+/-15.5 micromol/mol creatinine (n = 34); after 252 days, 18.2+/-12.5 (n = 16). Differences between <252 days group and control (p < 0.0001), and <252 days group and > or = 252 days groups (p = 0.0253) were statistically significant. Among the three groups based on ambient oxygen concentration (21%, 22-29%, and > or = 30%) there was no significant difference (p = 0.417). The more premature the infants were, the more intense was the oxidative stress, hence, it is the prematurity rather than the administered oxygen which causes oxidative stress in VLBW infants. Drury et al. ["Urinary 8-hydroxydeoxyguanosine in infants and children" Free Radic. Res. 28 (1998) 423-4281 measured urinary 8-OHdG of 28 infants (24-40 weeks gestation) and found no gestation or birthweight related differences. This discrepancy seemed to be because of difference in birth weights and sampling period of the subjects.
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PMID:Oxidative stress in very low birth weight infants as measured by urinary 8-OHdG. 1199 87

This article attempts to assess the nature, severity and management of the risks associated with pregnancy in chronic renal insufficiency and end-stage renal disease, including dialysis and transplant recipients. Women with serum creatinine levels of >125 mmol/l are at an increased risk for deterioration in renal function, hypertension with superimposed pre-eclampsia and obstetric complications. Rigid control of hypertension is crucial for a successful pregnancy outcome. A range of antihypertensive drugs are available with angiotensin converting enzyme inhibitors being contraindicated. Women on dialysis have low fertility rates that return to normal following renal transplantation. Immunosuppresive drugs are not associated with increased congenital anomalies. Transplant recipients are at an increased risk for infections that may have implications for the fetus. All groups have an increased risk for prematurity and intrauterine growth restriction. The percentage of pregnancies resulting in surviving infants in women with renal insufficiency and transplant recipients ranges from 80-100%. For women who conceive after dialysis, the likelihood of a surviving infant is approximately 50%.
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PMID:Chronic renal insufficiency in pregnancy. 1288 99


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