Anemia during pregnancy in a Chinese population

OBJECTIVES

To study prevalence, risk factors, and birth outcomes of women with anemia during pregnancy in a Chinese population.

METHODS

A retrospective cohort study was performed based on 16936 pregnancies delivered between January 1989 and December 1990 in Suzhou, China. Anemia was defined as hemoglobin less than 10 g/dl. Multivariate logistic regression was used to estimate odds ratio, 95% confidence interval, and to control for confounding variables.

RESULTS

The prevalence of anemia was 10.3% at the first trimester, 18.9% at the third trimester. Overall, 26.2% pregnant women experienced anemia in pregnancy. Anemia during early pregnancy was not associated with increased risk of adverse perinatal outcomes. However, anemia in later pregnancy was inversely associated with preterm birth and low birth weight.

CONCLUSIONS

Anemia during pregnancy does not increase the risk of poor birth outcomes.

[Relationship of age, sex, body weight, smoking, blood lipids and fibrinolytic activities in healthy subjects]

Relationship of plasma activities of tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor-1(PAI-1) with age, sex, body weight, smoking, blood lipids were studied in 131 healthy subjects. The results demonstrated that plasma PAI-1 activity increased with age and body weight. PAI-1/t-PA ratio was higher in smoking than in non-smoking subjects. With multivariate analyses, plasma PAI-1 activity was positively correlated with age, body weight index(BMI) in males, and positively correlated with low-density-lipoprotein-cholesterol(LDL) in females, and negatively correlated with plasma tPA activity. Plasma triglyceride, high-density-lipoprotein-cholesterol did not show a correlation to PAI-1 or tPA activity. It is indicated that age, BMI, blood lipids may contribute to moderate fibrinolytic activities and that smoking may affect fibrinolytic function.

[Plasma Lp (a) levels and correlation of Lp (a) with fibrinolysis activation in chronic renal failure]

Plasma Lp (a) concentration and activation of tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor-1(PAI-1) were determined in 50 patients with chronic renal failure (CRF) and in 50 healthy subjects. The results demonstrated that plasma concentration of Lp(a) was significantly higher and plasma t-PA activation was significantly lower in CRF patients than in healthy subjects. With multivariate analyses, plasma Lp(a) concentration was positively correlated with the total amount of 24 h uric protein, plasma BUN and uric protein concentration. Moreover, a negative significant correlation between plasma Lp(a) levels and t-PA activation was observed. Plasma Lp(a) levels did not show a correlation to PAI-1 activation. It is indicated that renal function may contribute to moderate plasma Lp(a) concentration and elevated Lp(a) levels may be related with fibrinolytic impairment.

Preeclampsia and cerebral palsy in low-birth-weight and preterm infants: implications for the current "ischemic model" of preeclampsia

OBJECTIVE

One of the prevailing hypotheses for the pathogenesis of preeclampsia is the "ischemic model." It assumes that reduced uteroplacental perfusion is the primary step and the point of convergence of diverse pathogenic processes in the development of preeclampsia. One might expect a fetus under such "ischemic conditions" to be at an increased risk of later development of cerebral palsy (CP). The objective of this study was to test the hypothesis that maternal preeclampsia increases the risk of CP in preterm and low-birth-weight infants.

METHODS

A meta-analysis was performed based on published articles identified by searching computerized databases (MEDLINE, EMBASE, CINAHL, Current Contents, Biological Abstracts, and Dissertation Abstracts) from 1966 through 1999. Ten observational studies on the association between preeclampsia and CP were identified based on prespecified inclusion criteria. Two independent reviewers extracted data and assessed the methodological quality of eligible articles. Odds ratios (OR) of CP for preeclampsia from individual studies were pooled.

MAIN OUTCOME MEASURE

Cerebral palsy.

RESULTS

In case-control studies, preeclampsia was associated with a statistically significant decreased risk of CP [pooled adjusted OR, 0.50; 95% confidence interval (CI), 0.33-0.81; p < 0.01). In cohort studies, preeclampsia was associated with a nonstatistically significant reduced risk of CP (pooled OR, 0.91; 95% CI, 0.35-2.41; p > 0.05).

CONCLUSIONS

Preeclampsia may be associated with a decreased risk of CP in preterm and low-birth-weight infants. This challenges the currently held belief that reduced uteroplacental perfusion is the unique pathophysiological process in preeclampsia.

Effect of therapeutic ionizing radiation on the human brain

We test a hypothesis that fractionated radiation therapy within a therapeutic dose range is associated with a dose-related change in normal brain, detectable by quantitative magnetic resonance imaging. A total of 33 patients were examined by quantitative magnetic resonance imaging to measure brain tissue spin-lattice relaxation time (T1) before treatment, and at various times during and after radiation therapy. A T1 map was generated at each time point, and radiation therapy isodose contours were superimposed on the corresponding segmented T1 map. Changes in white matter and gray matter T1 were analyzed as a function of radiation therapy dose and time since treatment, controlling for patient age and tumor site. In white matter, a dose level of more than 20 Gy was associated with a dose-dependent decrease in T1 over time, which became significant 6 months after treatment. There was no significant change in T1 of gray matter over time, at radiation therapy doses of less than 60 Gy. However, GM in close proximity to the tumor had a lower T1 before therapy. Our results represent the first radiation dose-response data derived from pediatric brain in vivo. These findings confirm that white matter is more vulnerable to radiation-induced change than is gray matter, and suggest that T1 mapping is sensitive to radiation-related changes over a broad dose range (20 to 60 Gy). Human white matter T1 is not sensitive to radiation therapy of less than 20 Gy, and gray matter T1 is unchanged over the dose range used to treat human brain tumor. The reduction of gray matter T1 near the tumor could result from compression of cortical parenchyma near the growing tumor mass, or from tumor cell invasion directly into the parenchyma. If brain T1 is a surrogate for radiation effect, reducing the volume of normal white matter receiving more than 20 Gy could be an important treatment planning goal.

Gestational diabetes mellitus: prevalence, risk factors, maternal and infant outcomes

OBJECTIVES

To study prevalence, risk factors, and maternal and infant outcomes of women with gestational diabetes mellitus (GDM).

METHODS

A retrospective cohort study was performed based on 111563 pregnancies delivered between 1991 through 1997 in 39 hospitals in northern and central Alberta, Canada. Multivariate logistic regression was used to estimate the odds ratios with 95% confidence intervals, and to control for confounding variables.

RESULTS

The prevalence of GDM was 2.5%. Risk factors for GDM included age >35 years, obesity, history of prior neonatal death, and prior cesarean section. Teenage mothers and women who drank alcohol were less likely to have GDM. Mothers with GDM were at increased risk of presenting with pre-eclampsia, premature rupture of membranes, cesarean section, and preterm delivery. Infants born to mothers with GDM were at higher risk of being macrosomic or large-for-gestational-age.

CONCLUSIONS

Specific conditions predispose to GDM which itself is associated with a significantly increased risk of maternal and fetal morbidity.

Tumor volume or dynamic contrast-enhanced MRI for prediction of clinical outcome of Ewing sarcoma family of tumors

BACKGROUND

The identification of risk factors that predict poor clinical outcome at the time of diagnosis could lead to intensified early therapy and improved outcome for pediatric patients with Ewing sarcoma family of tumors (ESFT).

OBJECTIVE

To compare the effectiveness of static magnetic resonance (MR) imaging measurements of tumor volume with variables obtained by dynamic contrast-enhanced MR imaging (DEMRI) in predicting ESFT outcome.

METHODS

MR examinations that included DEMRI were retrospectively reviewed. The analyses included 45 examinations of 21 patients with ESFT (performed from 1992 to 1996). Tumor volumes were measured on the static MR images, and the regions of interest were selected for DEMRI analysis. The relationships of static MR imaging and DEMRI variables with the probability of progression-free survival (PFS) and disease-free survival (DFS) were determined.

RESULTS

Larger tumor volume at the time of diagnosis predicted poorer PFS and DFS estimates. No DEMRI variable predicted outcome.

CONCLUSION

Determination of tumor volume by static MR imaging at the time of diagnosis is a simple and reliable method of predicting the clinical outcome of patients with ESFT. DEMRI is not as reliable a technique as static MR imaging for predicting the outcome of these patients.

Down-regulation of IL-12 p40 gene in Plasmodium berghei-infected mice

We analyzed the mechanism that causes suppression of IL-12 p40 gene induction during Plasmodium berghei infection. Although IL-12 together with IFN-gamma plays an important role in protection against pathogenic infection, the IL-12 p70 protein production of infected macrophages is lower than that by the uninfected macrophages. We showed in the present study that the induction of IL-12 p40 gene but not IL-12 p35 gene in macrophages of P. berghei-infected mice was profoundly inhibited. The inhibition was induced by interaction with macrophages that had contacted with P. berghei-infected erythrocytes and was mediated by a soluble factor, IL-10. There was comparable activation of NF-kappaB in uninfected and infected cells. The induction of IFN-regulatory factor-1 gene was comparable in transcription level in uninfected and infected cells, while the unidentified complex formation of IFN-regulatory factor-1 was observed in infected cells. Therefore, the inhibition of the IL-12 p40 gene induction appeared to be regulated at transcriptional regulation level of the gene.

Dynamic magnetic resonance imaging of regional contrast access as an additional prognostic factor in pediatric osteosarcoma

BACKGROUND

The purpose of this article was to evaluate the utility of a pharmacokinetically modeled measure of regional contrast access, based on dynamic contrast-enhanced magnetic resonance imaging (MRI) studies after preoperative chemotherapy, as a predictor of disease free survival in osteosarcoma.

METHODS

The kinetic parameters of a two-compartment pharmacokinetic model of MRI contrast agent accumulation were analyzed in relation to disease free survival in 31 patients who received protocol-based therapy for nonmetastatic osteosarcoma of the extremities. The modeled exchange rate of contrast between the plasma and the tumor extravascular extracellular fluid space served as a measure of regional contrast access. The prognostic impact of both the clinically accepted standard of histologic evaluation of tumor necrosis and the regional contrast access were analyzed with tumor size as an influential factor.

RESULTS

Although the histologic grade of response was not a statistically significant prognostic factor in these patients (P = 0.884), regional contrast access after preoperative chemotherapy was significantly predictive of disease free survival (P = 0.035) in the Cox proportional hazards model. Lower regional access before surgery and smaller tumor size were associated with a better treatment outcome. Log-rank analyses of Kaplan-Meier curves indicated that the impact of regional access was most pronounced in patients with larger tumors (P = 0.052). Higher regional access at presentation also was associated significantly with greater decreases during therapy.

CONCLUSIONS

Dynamic MRI estimates of regional contrast access after preoperative chemotherapy, when combined with tumor size, holds promise for the early identification of patients at risk of recurrence. The availability of such response predictors could facilitate the development of risk-adapted treatment approaches.

[Uvulopalatopharyngoplasty for the treatment of obstructive sleep apnea syndrome in 70 cases]

OBJECTIVE

To elevate the effect of uvulopalatopharyngoplasty (UPPP) and minimize the postoperative complications.

METHOD

The data of 70 patients with obstructive sleep apnea syndrome diagnosed with polysomnography were analyzed.

RESULT

15 cases (21%) reported unchanged snoring and apnea and hyponea index. 55 cases improved after UPPP for at least 6 months. The complications included hypertensive crisis (2 cases), respiratory embarrassment (4 cases) in period of paretic UPPP. After UPPP, The complications included local hemorrhage (1 case), wound dehiscence (2 cases), temporal velopalatal insufficiency (9 cases), one had suffocation after extraction of endotracheal tube.

CONCLUSION

Our results indicate that the strategies of improving the effect and avoiding the complications include: Excision of the lateral pharyngeal wall in retropalatal region and fat tissue in soft palate. Protection of palatosalpingeus and palatostaphylinus. Part preservation of uvula. Confirmation of the obstructive region. Choice of the anesthesia and preventive tracheotomy. Modified tracheotomy were safe and convenient when exchanging trachea canula.

Quantitation of mitomycin C in human ocular tissues by high-performance liquid chromatography-photo-diode array detection

A chromatographic method, which can quantitate mitomycin C (MMC) along with two antiglaucoma drugs, is described. The separation of MMC, alphagan and timolol was performed on a reversed-phase C18 column with water-methanol-trifluoroacetic acid (65:35:0.01, v/v) as the mobile phase. By monitoring at 360, 248 and 296 nm, the lower limits of detection for MMC, alphagan and timolol are, respectively, 1.0, 2.0 and 5.0 ng (injection amount) at three-time S/N ratio. The dynamic ranges of quantitation for the three drugs are, respectively, 1.0 ng-10.0 microg, 2.0 ng-10.0 microg and 5.0 ng-10.0 microg with linearity being larger than 0.9960. This method was applied to the determination of MMC levels in Tenon's and trabeculum tissues of 10 glaucoma patients. MMC levels in these tissues, which were obtained from glaucoma filtering surgery, were determined following a multiple extraction with methanol. The recovery of MMC for a two-batch extraction was better than 91.2%. The reproducibility of measurement for the MMC levels in these tissues is 2.5-6.0% RSD for triplicate injections. The intra-day variation of retention times for the MMC peaks was less than 1.6% RSD (n=3). The inter-day variation of retention times for the MMC peaks was less than 4.8% RSD (n=3). MMC was detectable in three trabeculum tissues out of 10 cases (ranging from 0.8 to 25.5 ng/mg specimen), while MMC was detected in nine Tenon's tissues out of 10 cases (ranging from 0.3 to 21.1 ng/mg specimen). The results obtained show that the method is sensitive and selective for the quantitation of MMC.

META-controlled env-initiated transcripts encoding superantigens of murine Mtv29 and Mtv7 and their possible role in B cell lymphomagenesis

Spontaneous germinal center (GC)-derived B cell lymphomas of SJL mice (RCS) transcribe a 1.8-kb Mtv-29 mRNA under control of the META-env promoter. The encoded vSAg29 stimulates syngeneic Vbeta16(+) CD4(+) T cells, thereby acquiring T cell help necessary for RCS growth. Other strains of B cell lymphoma-prone mice include Mtv29(+) C57L and MA/MyJ, and the Mtv29(-) Mtv7(+)-recombinant inbred strain, SW x J-1. The lymphomas of these mice produce similar mouse mtv-vSAg-encoding mRNA, as characterized by Northern blotting, PCR, and RNase protection. A 1.8-kb mRNA in C57L/J and MA/MyJ lymphomas hybridized with an Mtv29-specific oligonucleotide, whereas SW x J-1 lymphomas produced 1.8-kb transcripts hybridizing with an Mtv7-specific oligonucleotide. Similar META-env-initiated transcripts were absent from LPS-activated B cells from any strain examined but were detected in Peyer's patch RNA from SJL mice. Like typical SJL-derived RCS, all these lymphomas stimulated syngeneic CD4(+) T cells and Vbeta16(+) T hybridoma cells. Immunohistochemical staining of primary tumors showed the presence of peanut agglutinin binding (PNA(+)) highly mitotic lymphoblasts, suggesting their GC derivation. The findings indicate that this novel mRNA for Mtv29 is present in B cell lymphomas from several Mtv29(+) mouse strains. Additionally, this is the first description of the ability of Mtv7 to produce transcripts that are controlled and spliced identically to those of Mtv29 and that are expressed in SW x J-1, I-A(s+), lymphomas that also stimulate Vbeta16(+) T cells. Our results suggest an important role for mouse mtv-vSAgs and Vbeta16 T cell stimulation in the development of GC-derived murine B cell lymphomas.

Regulation of the PH-domain-containing tyrosine kinase Etk by focal adhesion kinase through the FERM domain

Etk/BMX, a member of the Btk family of tyrosine kinases, is highly expressed in cells with great migratory potential, including endothelial cells and metastatic carcinoma cell lines. Here, we present evidence that Etk is involved in integrin signalling and promotes cell migration. The activation of Etk by extracellular matrix proteins is regulated by FAK through an interaction between the PH domain of Etk and the FERM domain of FAK. The lack of Etk activation by extracellular matrix in FAK-null cells could be restored by co-transfection with wild-type FAK. Disrupting the interaction between Etk and FAK diminished the cell migration promoted by either kinase. Furthermore, inhibiting Etk expression in metastatic carcinoma cell lines with an antisense oligonucleotide blocks integrin-mediated migration of these cells. Taken together, our data indicate the essential role of the interaction of the PH domain of Etk and the FERM domain of FAK in integrin signalling.

Molecular modeling and biochemical characterization reveal the mechanism of hepatitis B virus polymerase resistance to lamivudine (3TC) and emtricitabine (FTC)

Success in treating hepatitis B virus (HBV) infection with nucleoside analog drugs like lamivudine is limited by the emergence of drug-resistant viral strains upon prolonged therapy. The predominant lamivudine resistance mutations in HBV-infected patients are Met552IIe and Met552Val (Met552Ile/Val), frequently in association with a second mutation, Leu528Met. The effects of Leu528Met, Met552Ile, and Met552Val mutations on the binding of HBV polymerase inhibitors and the natural substrate dCTP were evaluated using an in vitro HBV polymerase assay. Susceptibility to lamivudine triphosphate (3TCTP), emtricitabine triphosphate (FTCTP), adefovir diphosphate, penciclovir triphosphate, and lobucavir triphosphate was assessed by determination of inhibition constants (K(i)). Recognition of the natural substrate, dCTP, was assessed by determination of Km values. The results from the in vitro studies were as follows: (i) dCTP substrate binding was largely unaffected by the mutations, with Km changing moderately, only in a range of 0.6 to 2.6-fold; (ii) K(i)s for 3TCTP and FTCTP against Met552Ile/Val mutant HBV polymerases were increased 8- to 30-fold; and (iii) the Leu528Met mutation had a modest effect on direct binding of these beta-L-oxathiolane ring-containing nucleotide analogs. A three-dimensional homology model of the catalytic core of HBV polymerase was constructed via extrapolation from retroviral reverse transcriptase structures. Molecular modeling studies using the HBV polymerase homology model suggested that steric hindrance between the mutant amino acid side chain and lamivudine or emtricitabine could account for the resistance phenotype. Specifically, steric conflict between the Cgamma2-methyl group of Ile or Val at position 552 in HBV polymerase and the sulfur atom in the oxathiolane ring (common to both beta-L-nucleoside analogs lamivudine and emtricitabine) is proposed to account for the resistance observed upon Met552Ile/Val mutation. The effects of the Leu528Met mutation, which also occurs near the HBV polymerase active site, appeared to be less direct, potentially involving rearrangement of the deoxynucleoside triphosphate-binding pocket residues. These modeling results suggest that nucleotide analogs that are beta-D-enantiomers, that have the sulfur replaced by a smaller atom, or that have modified or acyclic ring systems may retain activity against lamivudine-resistant mutants, consistent with the observed susceptibility of these mutants to adefovir, lobucavir, and penciclovir in vitro and adefovir in vivo.

Immediate neurocognitive effects of methylphenidate on learning-impaired survivors of childhood cancer

PURPOSE

To test if methylphenidate (MPH) has an objective beneficial effect on immediate performance on tests of neurocognitive functions among learning-impaired survivors of childhood acute lymphoblastic leukemia (ALL) and malignant brain tumors (BT).

PATIENTS AND METHODS

From July 1, 1997 through December 31, 1998, 104 long-term survivors of childhood ALL or a malignant BT completed neurocognitive screening for learning impairments and concurrent problems with sustained attention. Eligibility criteria for the MPH trial included an estimated intelligence quotient greater than 50, academic achievement in the 16(th) percentile or lower for age in reading, math, or spelling, and an ability to sustain attention on a computerized version of the Conners' Continuous Performance Test (CPT) in the 16(th) percentile or lower for age and sex. Of the 104, 32 (BT, n = 25; ALL, n = 7) were eligible on the basis of these a priori criteria for a randomized, double-blinded, placebo-controlled trial of MPH. The patients ingested a placebo (lactose) or MPH (0.6 mg/kg; 20 mg maximum) and repeated selected portions of the screening battery 90 minutes later.

RESULTS

Compared to the 17 patients randomized to the placebo group, the 15 patients randomized to the MPH group had a significantly greater improvement on the CPT for sustained attention (errors of omission, P =.015) and overall index (P =.008) but not for errors of commission (indicative of impulsiveness) nor reaction times. A trend for greater improvement in the MPH group on a measure of verbal memory failed to reach statistical significance. No trend was observed for MPH effectiveness in improving learning of a word association task. No significant side effects from MPH were observed.

CONCLUSION

MPH resulted in a statistically significant improvement on measures of attention abilities that cannot be explained by placebo or practice effects.

Anemia during pregnancy and birth outcome: a meta-analysis

To determine the relationship between maternal anemia [hemoglobin (Hgb) < 10-11 g/dL] and various birth outcomes, a meta-analysis was conducted based on published literature identified by MEDLINE and manual search from 1966 through 1999. Odds ratios (OR) from selected studies were pooled according to the gestational age at anemia diagnosis. The meta-analysis shows that maternal anemia during early pregnancy was associated with slightly increased preterm birth [pooled adjusted OR (aOR): 1.32, 95% confidence interval (CI): 1.01-1.74], and nonstatistically significant increased low birth weight [pooled aOR: 1.39 (0.70-2.74)], and was not associated with fetal growth restriction [pooled aOR: 1.01 (0.73-1.38)]. However, there was a nonstatistically significant inverse relationship between anemia during late pregnancy and preterm birth [pooled aOR: 0.92 (0.54-1.84)] and low birth weight [pooled aOR: 0.80 (0.64-1.00)]. Anemia was not statistically significantly associated with hypertensive disorders of pregnancy regardless of stage of pregnancy [pooled OR: 0.80 (0.53-1.20)]. The relationship between anemia and perinatal mortality was inconclusive. A few studies indicated that severe maternal anemia (Hgb < 8-8.5 g/dL) was associated with increased risk of poor outcomes. We conclude that early pregnancy anemia is associated with slightly increased risk of preterm birth. The trend toward an inverse association of anemia determined during late pregnancy with preterm birth and low birth weight may reflect the benefit of plasma volume expansion.

Effect of ionizing radiation on the human brain: white matter and gray matter T1 in pediatric brain tumor patients treated with conformal radiation therapy

OBJECTIVE

To test a hypothesis that fractionated radiation therapy (RT) to less than 60 Gy is associated with a dose-related change in the spin-lattice relaxation time (T1) of normal brain tissue, and that such changes are detectable by quantitative MRI (qMRI).

METHODS

Each of 21 patients received a qMRI examination before treatment, and at several time points during and after RT. A map of brain T1 was calculated and segmented into white matter and gray matter at each time point. The RT isodose contours were then superimposed upon the T1 map, and changes in brain tissue T1 were analyzed as a function of radiation dose and time following treatment. We used a mixed-model analysis to analyze the longitudinal trend in brain T1 from the start of RT to 1 year later. Predictive factors evaluated included patient age and clinical variables, such as RT dose, time since treatment, and the use of an imaging contrast agent.

RESULTS

In white matter (WM), a dose level of greater than 20 Gy was associated with a dose-dependent decrease in T1 over time, which became significant about 3 months following treatment. In gray matter (GM), there was no significant change in T1 over time, as a function of RT doses < 60 Gy. However, GM in close proximity to the tumor had an inherently lower T1 before therapy. Neither use of a contrast agent nor a combination of chemotherapy plus steroids had a significant effect on brain T1.

CONCLUSION

Results suggest that T1 mapping may be sensitive to radiation-related changes in human brain tissue T1. WM T1 appears to be unaffected by RT at doses less than approximately 20 Gy; GM T1 does not change at doses less than 60 Gy. However, tumor appears to have an effect upon adjacent GM, even before treatment. Conformal RT may offer a substantial benefit to the patient, by minimizing the volume of normal brain exposed to greater than 20 Gy.

[The effect of methylenum coeruleum in laparoscope cholecystectomy]

OBJECTIVES

To help the operator correctly judge in operation the cystic gall duct and choledoch, and eliminate the operation wound.

METHODS

To divide laparoscope cholecystectomy patients with the same weight at the same period into two groups: development group (589 cases) using methylenum coeruleum and conducting cholecysto-puncture visualization during the operation in which colors of cholecyst, cystic gall duct and choledoch turn blue; comparative group (553 cases) using regular laparoscope cholecystectomy.

RESULTS

The two groups differed remarkably in operation time, complication, and transferring rate (P < 0.01).

CONCLUSIONS

Methylenum coeruleum development technology in operation is a kind of visualization to help the operator judge in operation Calot triangular anatomy construction correctly, reduce the operation time obviously, and increase the rate of success.

Spatiotemporal expression of BDNF in the hippocampus induced by the continuous intracerebroventricular infusion of beta-amyloid in rats

The beta-amyloid protein (Abeta) is the major component of senile plaques found in the brain in Alzheimer's disease (AD). Its neurotoxic properties in vivo, however, are not well defined. Since the expression of neurotrophin genes is considered an important component of the intrinsic neuroprotective response to insults, we analyzed the gene expression of neurotrophins in the brains of rats which received a continuous infusion of Abeta-(1-42) into the cerebroventricle. Northern blot analysis revealed a significant increase in brain-derived neurotrophic factor (BDNF) expression in the hippocampus but no change in the cerebral cortices. The alteration peaked on days 3-7 and returned to the basal level on day 14 after the start of Abeta-(1-42) infusion. No significant changes in nerve growth factor or neurotrophin-3 mRNA expression were observed. The infusion of Abeta-(1-40) and (25-35) also triggered the expression of BDNF mRNA, whereas neither Abeta-(40-1) nor (1-16) had any effect. In situ hybridization histochemistry revealed that the expression mainly occurred in the hilus and granular layer of the dentate gyrus and to a lesser extent in the pyramidal neurons of the CA1 region. These results demonstrate that the continuous intracerebroventricular infusion of Abeta induces selective and spatiotemporal expression of BDNF mRNA in the hippocampus.

Subtle white matter volume differences in children treated for medulloblastoma with conventional or reduced dose craniospinal irradiation

Medulloblastoma is the most common malignant brain tumor in children, and approximately seventy percent of average-risk patients will achieve long-term survival. Craniospinal irradiation (CSI), combined with chemotherapy and surgery, is currently the mainstay of treatment but places children who survive at risk for serious neurocognitive sequelae. These sequelae are intensified with a younger age at treatment, greater elapsed time following treatment, and an increased radiation dose. Many newer treatment approaches have attempted to address this problem by reducing the dose of the CSI component of radiation therapy while maintaining the current survival rates. This study evaluates longitudinal MR imaging during therapy to assess the impact of the two CSI doses (conventional [36 Gy] and reduced [23.4 Gy]) on normal appearing white matter volumes (NAWMV) evaluated in a single index slice. Twenty-six children and young adults at least three years of age enrolled on an institutional protocol for newly diagnosed, previously untreated primary medulloblastoma had at least four MR examinations over a minimum nine month period following CSI. These serial volumes were evaluated as a function of time since CSI in three analyses: 1) all subjects, 2) subjects stratified by age at CSI, and 3) subjects stratified by CSI dose. The first analysis demonstrated that medulloblastoma patients treated with CSI have a significant loss of NAWMV in contradistiction to normally expected maturation. Stratifying the patients by age at CSI found no significant differences in the rate of NAWMV loss. The final analysis stratified the patients by CSI dose and revealed that the rate of NAWMV loss was 23% slower in children receiving reduced-dose. Serial quantitative MR measures of NAWMV may provide a neuroanatomical substrate for assessing functional impact of CSI on normal brain function following treatment for medulloblastoma.

Cloning, characterization, and functional studies of human and mouse glycoprotein VI: a platelet-specific collagen receptor from the immunoglobulin superfamily

Injuries to the vessel wall and subsequent exposure of collagen from the subendothelial matrix result in thrombus formation. In physiological conditions, the platelet plug limits blood loss. However, in pathologic conditions, such as rupture of atherosclerotic plaques, platelet-collagen interactions are associated with cardiovascular and cerebral vascular diseases. Platelet glycoprotein VI (GPVI) plays a crucial role in collagen-induced activation and aggregation of platelets, and people who are deficient in GPVI suffer from bleeding disorders. Based on the fact that GPVI is coupled to the Fc receptor (FcR)-gamma chain and thus should share homology with the FcR chains, the genes encoding human and mouse GPVI were identified. They belong to the immunoglobulin (Ig) superfamily and share 64% homology at the protein level. Functional evidence demonstrating the identity of the recombinant protein with GPVI was shown by binding to its natural ligand collagen; binding to convulxin (Cvx), a GPVI-specific ligand from snake venom; binding of anti-GPVI IgG isolated from a patient; and association to the FcR-gamma chain. The study also demonstrated that the soluble protein blocks Cvx and collagen-induced platelet aggregation and that GPVI expression is restricted to megakaryocytes and platelets. Finally, human GPVI was mapped to chromosome 19, long arm, region 1, band 3 (19q13), in the same region as multiple members of the Ig superfamily. This work offers the opportunity to explore the involvement of GPVI in thrombotic disease, to develop alternative antithrombotic compounds, and to characterize the mechanism involved in GPVI genetic deficiencies. (Blood. 2000;96:1798-1807)

[Preliminary clinical comparison of HLF and ELF regimen in the treatment of advanced gastric carcinoma in middle-aged and elderly patients]

OBJECTIVE

To observe the therapeutic effects and toxicity of HLF (hydroxycamptothecin HCPT/leucovorin LV/fluorouracil 5-Fu) regimen and ELF (etoposide VP-16/LV/5-Fu) regimen in middle-aged and elderly patients with advanced gastric carcinoma.

METHODS

A group of twenty-five cases were treated with HLF regimen, and the other group of 23 cases were treated with ELF regimen.

RESULTS

Of the 25 cases treated with HLF regimen, there was no complete remission (CR), but there were 12 partial response (PR), 11 no response (NC), and 2 had progressive disease (PD). The response rate (RR) was 48.0%. Of the 23 patients treated with ELF regimen, there was no CR, there were 9 PR, 11 NC, and 3 PD. The RR was 39.1% (P > 0.05). The main toxicity was myelosuppression and stomatocace. Grade III-IV stomatocace in HLF regimen group (68.0%) was more commonly seen than that in ELF regimen group (39.1%, P < 0.05). There was no cardiac or renal toxicity observed.

CONCLUSION

HLF regimen is promising for treatment of advanced gastric carcinoma in middle-aged and elderly patients with the merits of low toxicity affecting heart, kidney and bladder except stomatocace, which is worthy of further clinical trial.

Maternal smoking and preeclampsia

OBJECTIVE

To study the relationship between maternal smoking and preeclampsia and whether this association differs between primiparous and multiparous women.

STUDY DESIGN

We conducted a population-based, retrospective, cohort study of 58,216 singleton pregnancies from northern and central Alberta, Canada, between 1995 and 1997. Multivariate logistic regression was used to control for maternal alcohol consumption, drug dependence, maternal age, maternal weight, prior intrauterine growth restriction and other confounders.

RESULTS

Maternal smoking was associated with a significantly reduced overall risk of preeclampsia (adjusted odds ratio [aOR]: .61; 95% confidence interval [CI]: .50-.75; P < .01). Stratified analyses showed that in primiparous pregnancies, maternal smoking was associated with a significantly decreased risk (aOR: .63; 95% CI: .50-.80; P < .01); in multiparous women, maternal smoking was not associated with a statistically significant decreased risk of preeclampsia (aOR: 0.72; 95% CI: .51-1.02; P > .05).

CONCLUSION

Maternal smoking is protective against preeclampsia. Understanding the underlying biologic mechanisms of this protective effect may advance our knowledge of the pathogenesis of preeclampsia.

Risk factors for development of diabetes mellitus in women with a history of gestational diabetes mellitus

OBJECTIVE

To determine whether diabetes recurs in their later life when women have a history of gestational diabetes mellitus (GDM) or abnormal glucose tolerance test (impaired glucose tolerance, IGT).

METHODS

Three groups of women were investigated at 5-10 years postpartum. GDM group (n = 45) had been diagnosed as having GDM in their previous pregnancy. IGT group (n = 31) had a history of abnormal glucose tolerance test during previous pregnancy. Normal control group (n = 39) was normal previous pregnant population. Their previous obstetric and medical histories were thoroughly reviewed. Fasting plasma glucose (FPG) and oral glucose (75 g) tolerance test (OGTT) were repeated in all women.

RESULTS

Diabetes mellitus (DM) was diagnosed in 33.3% of patients in the GDM group, while in 9.7% in the IGT group and in 2.6% in the normal control group. Incidence of recurring DM in later life was significant higher in the GDM group (P = 0.017). When one or more blood glucose values exceeding WHO criteria for diagnosis of diabetes in their previous pregnancy, the incidence of DM in later life was 60% (3/5, including GDM in women having four abnormal OGTT values), 41.7% (5/12) in women having three, 25% (7/28) in women having two and 9.7% (3/31) in women having one. The women with DM, also with a history of GDM and abnormal OGTT in previous pregnancy, tends to have a high pregnant body mass index (BMI > 25 kg/m2).

CONCLUSION

The women suffering from GDM during previous pregnancy have a high risk of recurrence DM. Two or more abnormal OGTT values during pregnancy, blood glucose level exceeding the maximal values at 1 and 2 hours after oral glucose loading and high pregnant BMI are concluded to be useful factors in predicting the recurring DM in their later life.

Association of preeclampsia with high birth weight for age

OBJECTIVE

The purpose of this study was to examine the effect of gestational hypertension and preeclampsia on fetal growth.

STUDY DESIGN

A retrospective cohort study was conducted on the basis of 97,270 pregnancies delivered between 1991 and 1996 in 35 hospitals in northern and central Alberta, Canada. Univariate and multivariate logistic analyses were performed to examine the impact of preeclampsia and gestational hypertension on high-birth-weight (> or =4200 g), large-for-gestational-age, low-birth-weight (<2500 g), and small-for-gestational-age babies.

RESULTS

The rate of high-birth-weight fetuses in women with gestational hypertension (7. 3%) was higher than in those with normal blood pressure (5.6%). After we controlled for confounders, the adjusted odds ratio of high birth weight was 1.44 (95% confidence interval, 1.21-1.70) in women with gestational hypertension. Preeclampsia was also associated with a statistically nonsignificant (P =.054) increased risk of high birth weight (adjusted odds ratio, 1.40; 95% confidence interval 0. 99-1.98). The rate of large-for-gestational-age babies was significantly higher in women with gestational hypertension (4.5%) and preeclampsia (4.7%) than in those with normal blood pressure (2. 2%), with adjusted odds ratios of 1.50 (95% confidence interval, 1. 22-1.85) for gestational hypertension and 1.87 (95% confidence interval, 1.31-2.67) for preeclampsia. Concurrently, women who had gestational hypertension were also at higher risk of having low-birth-weight (adjusted odds ratio, 2.4; 95% confidence interval, 2.13-2.93) and small-for-gestational-age (adjusted odds ratio, 2.04; 95% confidence interval, 1.68-2.48) babies. Women with preeclampsia were also at markedly higher risk of having low-birth-weight (adjusted odds ratio, 4.14; 95% confidence interval, 3.32-5.15) and small-for-gestational-age (adjusted odds ratio, 2.56; 95% confidence interval, 1.92-3.41) babies.

CONCLUSIONS

There is a significant association of preeclampsia and gestational hypertension with large-for-gestational-age infants, in addition to a significant association with low-birth-weight and small-for-gestational-age infants. This study challenges the currently held belief that reduced uteroplacental perfusion is the unique pathophysiologic process in preeclampsia.

The inhibitory effects of IFN alpha-2b on EGFR expression and growth of cultured subconjunctival fibroblasts

To investigate to what extent the growth of cultured subconjunctival fibroblasts was regulated by epidermal growth factor receptor (EGFR), we observed the expression of EGFR inhibited by interferon alpha-2b (IFN alpha-2b) and determined the growth of cultured subconjunctival fibroblasts by immunohistochemical and MTT methods. The linear relationships between the concentration of IFN alpha-2b and EGFR expression or growth were y = 1252.7-554.61 lgx (r = -0.98, P < 0.01), y = 0.523-0.0421 lgx (r = -0.93, P < 0.05) respectively. The concentration of IFN alpha-2b at doubled IC50 to EGFR (6.55 x 10(3) IU/ml) only inhibited the cell growth by 25.13%. The results suggested that the growth of subconjunctival fibroblasts may be controlled by many other growth factors because it was only partially inhibited by decreasing EGFR expression.

[Relationship of lipoprotein(a) to fibrinolytic activities in healthy subjects]

Plasma tissue-type plasminogen activator(tPA) and plasminogen activator inhibitor(PAI-1) and lipoprotein(a) [Lp(a)] in 133 healthy subjects were determined. The results demonstrated that PAI-1 activity was higher in Lp(a) > or = 0.3 g.L-1 group than Lp(a) < 0.3 g.L-1 group (P < 0.05). Univariate statistical analyses showed Lp(a) concentration was positively associated with PAI-1 activity (P < 0.01), but not with age, sex, body mass index, blood lipids or tPA activity.

Testing secondary hypotheses following sequential clinical trials

Sequential monitoring in a clinical trial poses difficulty in hypotheses testing on secondary endpoints after the trial is terminated. The conventional likelihood-based testing procedure that ignores the sequential monitoring inflates Type I error and undermines power. In this article, we show that the power of the conventional testing procedure can be substantially improved while the Type I error is controlled. The method is illustrated with a real clinical trial.

Accuracy of MR imaging for detecting epiphyseal extension of osteosarcoma

BACKGROUND

Too few patients are receiving epiphyseal-sparing limb salvage procedures for osteosarcoma.

OBJECTIVE

To determine how magnetic resonance (MR) imaging can best predict the epiphyseal extension of osteosarcoma.

MATERIALS AND METHODS

Forty children underwent complete pretreatment static and dynamic contrast-enhanced MR imaging (DEMRI). Static MR images [T1-weighted and short tau inversion recovery (STIR)] of the epiphyses were read in three ways: (1) for suspicion of any abnormality (tumor or edema), (2) for suspicion of tumor, excluding suspected edema, and (3) validating the second method by using a scale to rate the likelihood of tumor. Presentation imaging was compared to histopathologic findings after chemotherapy and resection. The receiver operating characteristic (ROC) method was used to analyze the scaled ratings of static MR and DEMRI values.

RESULTS

At delayed resection, 20 of 40 children with osteosarcoma had confirmed epiphyseal tumor; however, 32 epiphyses were abnormal on STIR and 28 abnormal on T1. Differentiating suspected tumor from edema increased the accuracy to an Az (area under the ROC curve) of 0.94 for both T1-weighted and STIR static sequences. T1-weighted MR had better specificity and STIR better sensitivity at any given rating. DEMRI was slightly less accurate (Az = 0.90).

CONCLUSION

Static MR imaging most accurately detected epiphyseal extension of osteosarcoma when readers distinguished suspected tumor from edematous or normal tissue.

[A study on the telomerase activity in lung cancer and its clinical significance.]

BACKGROUND

To investigate the telomerase activity in human lung cancer and its clinical significance.

METHODS

Sixty human lung cancer specimens (NSCLC 45 , SCLC 15) , seven tuberculosis specimens and seven inflammatory pesudotumor were examined for telomerase activity by means of TRAP (telomeric repeat amplification protocol) based on polymerase chain reaction.

RESULTS

In NSCLC , telomerase positivity was 73. 3 %(33/ 45) with weak to moderate activity (172 TPG) , whereas 14 of 15 SCLC (93. 3 %) were positive with strong activity (288 TPG) , and all tuberculosis and inflammatory pseudotumor were telomerase negativity. The telomerase activity was significantly higher in SCLC than that in NSCLC ( P < 0. 05) , and was closely associated with the differentiation , size of the cancer , lymph node metastasis , and TNM staging ( P < 0. 05) .

CONCLUSIONS

The results suggest that telomerase may be regarded as one of the prognostic factor in lung cancer.

Silent lacunar lesions detected by magnetic resonance imaging of children with brain tumors: a late sequela of therapy

BACKGROUND

Cerebral lacunes, which generally appear on magnetic resonance imaging as foci of white matter loss, usually occur in adults after ischemic infarcts. We report the development of lacunes in children after therapy for brain tumors.

PATIENTS AND METHODS

We reviewed the clinical characteristics and radiologic studies of 524 consecutive children with brain tumors treated over a 10-year period. We documented the neuropsychologic findings associated with lacunes and the factors predictive of lacunar development.

RESULTS

Lacunes developed in none of the 103 patients observed or treated with surgery alone. Twenty-five of the 421 patients treated with chemotherapy or radiation therapy or both had lacunes. Patients were a median of 4.5 years old at the time of both diagnosis (range, 0.3 to 19.8 years) and radiotherapy (range, 1.5 to 20 years). Fourteen patients were treated with craniospinal irradiation, and 11 were treated with local radiotherapy. The median time from radiotherapy to the appearance of lacunes was 2.01 years (range, 0.26 to 5.7 years). For all patients, lacunes were an incidental finding with no corresponding clinical deficits. The factor most predictive of lacunar development was age less than 5 years at the time of radiotherapy (P =.010). There was no significant difference in estimated decline in intelligence quotient scores between patients with lacunes and age and diagnosis-matched controls.

CONCLUSION

Lacunes may be caused by therapy-induced vasculopathy in children with brain tumors, with the most significant predictor being age less than 5 years at the time of radiotherapy.

[Detection of distortion-product otoacoustic emissions in well-drilling workers]

OBJECTIVE

To understand the value of using distortion product of otoacoustic emissions(DPOAE) in monitoring noise-induced hearing-loss.

METHOD

The amplitude and the positive rates of DPOAE were detected in 102 well-drilling workers (195 ears).

RESULT

The amplitude and the positive rates of DPOAE declined significantly in noise groups against control. With the increase of working-age the positive rates of DPOAE was decrease. The DPOAE amplitudes and the positive rates of noise group with normal pure tone threshold were obvious lower than that in controls. There were negative relationship between pure tone threshold in high-frequency and the positive rates.

CONCLUSION

The DPOAE can reflect the cochlea's function of labors working in noise condition well. Contrast with the pure tone audiometry, DPOAE was more sensitive and more objective.

Sample size calculation for planning group sequential longitudinal trials

Procedures are developed in this paper for sample size calculations for planning a group sequential longitudinal trial with various correlation structures, using a test statistic based on generalized estimating equations (Lee, Kim and Tsiatis) and group sequential boundaries based on type I error spending functions (Lan and DeMets).

In vitro evaluation of hepatitis B virus polymerase mutations associated with famciclovir resistance

Several mutations (V521L, P525L, L528M, T532S, and V555I) in the gene for hepatitis B virus (HBV) polymerase have been identified in HBV isolated from patients that displayed break-through viremia during famciclovir treatment. To determine whether these mutations cause phenotypic resistance to famciclovir, we compared the inhibition constants (K(i)) of penciclovir triphosphate (PCVTP, the active metabolite of famciclovir) for recombinant wild-type and mutant HBV polymerases containing these mutations. In in vitro enzymatic assays, the V555I mutation displayed the most resistance (with K(i) increased by 6.2-fold) to PCVTP. The V521L and L528M mutations showed moderately decreased sensitivity to PCVTP (K(i) increased by >3-fold). We also analyzed the cross-resistance profiles of these variants for adefovir and lamivudine, two other antiviral agents that also inhibit DNA replication by HBV polymerase. All 5 famciclovir-associated mutations were sensitive to adefovir diphosphate (ADVDP) in in vitro enzymatic assays (<2.3-fold decreased sensitivity). The V521L, L528M, and T532S mutations were also sensitive to lamivudine triphosphate (LAMTP); however, the P525L and V555I mutations displayed moderately decreased sensitivity to LAMTP in enzymatic assays (3.6-fold decreased sensitivity). The lamivudine-resistant mutations M552I, M552V, and L528M+M552V, which were previously shown to display 8- to 25-fold resistance to LAMTP, were less resistant (< or = 3.1-fold) to PCVTP.

Fulminant hepatic failure resulting from lamivudine-resistant hepatitis B virus in a renal transplant recipient: durable response after orthotopic liver transplantation on adefovir dipivoxil and hepatitis B immune globulin

BACKGROUND

Mutations in the hepatitis B virus (HBV) genome may occur during therapy.

METHODS

We report an asymptomatic HBV carrier who underwent transplantation for end-stage renal disease. She developed an HBV flare 6 months after transplantation and was placed on lamivudine. After initial rapid improvement, she relapsed clinically and virologically. She decompensated with jaundice, peripheral edema, ascites, encephalopathy, coagulopathy, and hepatorenal syndrome. A liver biopsy specimen revealed submassive necrosis.

RESULTS

Emergency liver transplantation was performed: lamivudine was discontinued. Hepatitis B immunoglobulin and adefovir dipivoxil were initiated. Sixteen months after orthotopic liver transplantation, she is HBV DNA seronegative with normal liver enzymes. Sequencing of HBV polymerase gene from preliver transplantation sera did not detect the usual lamivudine resistance mutations in the YMDD motif but instead two other mutations (F514-->L, L528-->M). Lamivudine resistance was demonstrated in vitro.

CONCLUSIONS

Asymptomatic HBV carriers may reactivate following renal transplantation after immunosuppression. Resistance to lamivudine may result in severe hepatic damage in immunocompromised patients.

Functional human corneal equivalents constructed from cell lines

Human corneal equivalents comprising the three main layers of the cornea (epithelium, stroma, and endothelium) were constructed. Each cellular layer was fabricated from immortalized human corneal cells that were screened for use on the basis of morphological, biochemical, and electrophysiological similarity to their natural counterparts. The resulting corneal equivalents mimicked human corneas in key physical and physiological functions, including morphology, biochemical marker expression, transparency, ion and fluid transport, and gene expression. Morphological and functional equivalents to human corneas that can be produced in vitro have immediate applications in toxicity and drug efficacy testing, and form the basis for future development of implantable tissues.

Survival and neurodevelopmental outcome of young children with medulloblastoma at St Jude Children's Research Hospital

PURPOSE

Young children treated for medulloblastoma are at especially high risk for morbidity and mortality from their disease and therapy. This study sought to assess the relationship, if any, between patient outcome and M stage. Neuropsychologic and endocrine outcomes were also assessed.

PATIENTS AND METHODS

Twenty-nine consecutively diagnosed infants and young children were treated for medulloblastoma at St Jude Children's Research Hospital between November 1984 and December 1995. All patients were treated with the intent of using postoperative chemotherapy to delay planned irradiation.

RESULTS

The median age at diagnosis was 2.6 years. Six patients completed planned chemotherapy without progressive disease and underwent irradiation at completion of chemotherapy. Twenty-three children experienced disease progression during chemotherapy and underwent irradiation at the time of progression. The 5-year overall survival rate for the entire cohort was 51% +/- 10%. The 5-year progression-free survival rate was 21% +/- 8%. M stage did not impact survival. All patients lost cognitive function during and after therapy at a rate of -3.9 intelligence quotient points per year (P =.0028). Sensory functions declined significantly after therapy (P =.007). All long-term survivors required hormone replacement therapy and had growth abnormalities.

CONCLUSION

The majority of infants treated for medulloblastoma experienced disease progression during initial chemotherapy. However, more than half of these patients can be cured with salvage radiation therapy, regardless of M stage. The presence of metastatic disease did not increase the risk of dying from medulloblastoma. All patients treated in this fashion have significant neuropsychologic deficits. Our experience demonstrates that medulloblastoma in infancy is a curable disease, albeit at a significant cost.

[Observation of the long-term serum insulin level in women with gestational diabetes history]

OBJECTIVE

To determine beta-cell's function by measuring blood glucose level and serum insulin level in women who had history of gestational diabetes mellitus (GDM), but had no long-term diabetes.

METHODS

30 cases in GDM history group, 29 cases in abnormal oral glucose tolerance test(OGTT) history group, and 38 cases in control Group were followed up to undergo fasting blood sugar test and 75 g glucose load test, and to measure their insulin levels. All the cases had no long-term diabetes.

RESULT

(1) the blood glucose levels at 2 hour in GDM history group and abnormal OGTT history group were higher than that in control group especially the former, which was very significantly higher (P < 0.001). (2) The insulin at 2 hours in GDM history group was higher than that in control group (P = 0.00067).

CONCLUSION

Though women with GDM history do not have long-term diabetes, insulin resistance still exists, postings a possible sign for future diabetes attack.

Characterization of human acid sphingomyelinase purified from the media of overexpressing Chinese hamster ovary cells

A rapid purification method was developed to isolate milligram quantities of human acid sphingomyelinase from the media of overexpressing Chinese hamster ovary cells. The purified, recombinant enzyme (rhASM) had physical and kinetic characteristics that were consistent with those reported for the non-recombinant enzyme, including an acidic pH optimum and sensitivity to sulfhydryl reducing reagents and the zinc specific chelator, 1, 10-phenanthroline. A novel assay using fluorescently conjugated sphingomyelin was developed to explore the substrate binding properties of rhASM. Substrate binding required a fatty acid chain length of at least six carbons and the presence of the phosphocholine headgroup on sphingomyelin. Substrate binding also required an acidic pH, and was inhibited by pretreatment of the enzyme with sulfhydral reducing reagents or 1,10-phenanthroline. rhASM was rapidly internalized by cultured skin fibroblasts from Niemann-Pick disease (NPD) patients, and approximately 50% of this uptake was dependent on the mannose 6-phosphate receptor system. Studies using FITC-labeled rhASM revealed that by 1 h the internalized enzyme was localized to acidic compartments and could degrade sphingomyelin, the first demonstration that a lysosomal sphingolipid hydrolase can be fluorescently labeled and retain its biological activity. Intravenous injection of rhASM into ASM knock-out mice showed that the t(1/2) in the plasma was less than 5 min, and that the majority of the injected enzyme was taken up by the liver, followed by the spleen. Thus, these studies lay the foundation for future structure/function investigations of ASM, further investigations into this enzyme's role in ceramide mediated signal transduction, and the evaluation of enzyme replacement therapy for NPD using the mouse model.

Differential strain susceptibility following 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration acts in an autosomal dominant fashion: quantitative analysis in seven strains of Mus musculus

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has been used as a potent neurotoxin to approximate, in animals, the pathology that is observed in human Parkinson's disease. In this study, we examine the toxicity of MPTP in seven strains of mice, spanning a genetic continuum of Mus musculus as a prelude to uncovering complex traits associated with MPTP toxicity. Seven days following injection of 80 mg/kg MPTP (4x20 mg/kg every 2 h), we find that the individual mouse strains exhibit dramatic differences in SNpc neuron survival, ranging from 63% cell loss in C57BL/6J mice to 14% cell loss in Swiss-Webster (SW) mice. In order to determine if the susceptibility trait was dominant, additive or recessive, we crossed C57Bl/6J mice with either SWR/J or AKR/J mice and examined the effect of MPTP on F1 C57BL/6JxSWR/J or F1 C57BL/6JxAKR/J animals. We find that all of the F1 animals were phenotypically identical to the C57BL/6J animals. In addition, no gender differences were noted in any of the MPTP-treated inbred mice or in the F1 animals. These results suggest that susceptibility to cell loss following MPTP is autosomal dominant and this polymorphism is carried on the C57BL/6J allele.

Diffuse T1 reduction in gray matter of sickle cell disease patients: evidence of selective vulnerability to damage?

The objective of our study was to test the hypothesis that subtle brain abnormality can be present in pediatric sickle cell disease (SCD) patients normal by conventional MR imaging (cMRI). We examined 50 SCD patients to identify those patients who were normal by cMRI. Quantitative MR imaging (qMRI) was then used to map spin-lattice relaxation time (T1) in a single slice in brain tissue of all 50 patients and in 52 healthy age-similar controls. We also used a radiofrequency (RF) pulse to saturate blood spins flowing into the T1 map slice, to characterize the effect of blood flow on brain T1. Abnormalities were noted by cMRI in 42% (21/50) of patients, with lacunae in 32%, and encephalo malacia in 20%. Brain T1 in patients normal by cMRI was significantly lower than controls, in caudate, thalamus, and cortex (p < or =0.007), and regression showed that gray matter T1 abnormality was present in caudate and cortex by age 4 (p < or =0.002). In patients abnormal by cMRI, T1 reductions in gray matter were larger and more significant. White matter T1 was not significantly increased except in patients abnormal by cMRI. RF saturation in a slab below the T1 map produced no significant change in T1, compared to RF saturation in a slab above the T1 map, suggesting that inflow of untipped spins in blood does not cause an artifactual shortening of T1. Gray matter T1 abnormality was present in patients normal by cMRI, while white matter T1 abnormality was present only in patients also abnormal by cMRI. These findings suggest that gray matter is selectively vulnerable to damage in pediatric SCD patients and that white matter damage occurs later in the disease process. Our inability to find an effect from saturation of inflowing blood implies that rapid perfusion cannot account for T1 reduction in gray matter.

Independence of evolutionary and mutational rates after transmission of avian influenza viruses to swine

In 1979, an H1N1 avian influenza virus crossed the species barrier, establishing a new lineage in European swine. Because there is no direct or serologic evidence of previous H1N1 strains in these pigs, these isolates provide a model for studying early evolution of influenza viruses. The evolutionary rates of both the coding and noncoding changes of the H1N1 swine strains are higher than those of human and classic swine influenza A viruses. In addition, early H1N1 swine isolates show a marked plaque heterogeneity that consistently appears after a few passages. The presence of a mutator mutation was postulated (C. Scholtissek, S. Ludwig, and W. M. Fitch, Arch. Virol. 131:237-250, 1993) to account for these observations and the successful establishment of an avian H1N1 strain in swine. To address this question, we calculated the mutation rates of A/Mallard/New York/6750/78 (H2N2) and A/Swine/Germany/2/81 (H1N1) by using the frequency of amantadine-resistant mutants. To account for the inherent variability of estimated mutation rates, we used a probabilistic model for the statistical analysis. The resulting estimated mutation rates of the two strains were not significantly different. Therefore, an increased mutation rate due to the presence of a mutator mutation is unlikely to have led to the successful introduction of avian H1N1 viruses in European swine.

Subtle brain abnormalities in children with sickle cell disease: relationship to blood hematocrit

Our objective was to test a hypothesis that subtle brain abnormality can be present in pediatric sickle cell disease (SCD) patients who are clinically free of stroke. We prospectively compared 50 patients with 52 healthy age-similar controls, using quantitative magnetic resonance imaging. A previously validated precise and accurate inversion-recovery method was used to measure T1 in a slice at the basal ganglia. We also used the Wechsler test to measure intelligence quotient (IQ) in a randomly selected subset of 27 patients. Brain T1 was significantly lower in patients in every gray matter structure evaluated but in none of the white matter structures. Regression suggests that T1 in caudate, nucleus pulvinares, and cerebral cortex was abnormal by age 4 years. Psychometric testing showed that 33% of patients were functioning in the range of mild mental deficiency (IQ, 50-70), compared with a published prevalence of 1.45% in inner-city black children. Thus, in our patients, SCD was associated with a 23-fold increase in the risk of mild mental deficiency. Full-scale IQ of SCD patients was a function of hematocrit (Hct), and when Hct was used to stratify patients, those with an Hct of less than 27% had significantly lower psychometric test scores, and significantly lower gray matter T1, than those with an Hct of 27 or more. Both cognitive deficits and subtle T1 abnormalities were associated with a low Hct, and both could be present when conventional magnetic resonance imaging findings were normal. Our findings suggest that chronic hypoxia of brain tissue can occur in SCD patients free of clinical stroke.

[Rat retinal ganglion cells in culture]

OBJECTIVE

To establish a culture system for retinal ganglion cells (RGCs) in order to lay a foundation for the experimental research in vitro.

METHODS

The retinae of 16 postnatal 2 - 3 day Sprague-Dawley rats were dissected into cell suspension with trypsin digestion. The cell suspension was implanted in 24 well culture plates with a cover slide 1 cm(2) in size and covered with murine tail collagen preplaced in each well (4 x 10(5) cells/well) and cultured under 37 degree C in an incubator with 5% CO(2). The cells were identified by immunocytochemical method with anti-rat Thy -1.1 monoclonal antibody after culture for 1, 3, 5 days, respectively, and the number of RGCs and its axon-growth percentage were counted in each 10-field high power (HP, 200 x) view under light microscope.

RESULTS

The RGCs cultured in murine tail collagen tissue grew very well. Some cells possessed axons and some axons connected in networks. The RGC number and its axon-growth percentage were (401 +/- 9) cells/10 HP and (25.34 +/- 0.72)% in 1-day-culture, (351 +/- 6) cells/10 HP and (35.16 +/- 2.22)% in 3-day-culture, (109 +/- 8) cells/10 HP and (69.84 +/- 0.97)% in 5-day-culture, respectively.

CONCLUSION

RGCs can be cultured successfully and the murine tail collagen tissue is a good substratum for RGC survival in vitro.