In utero morphological effects of hydroxyurea on the fetal development in Sprague-Dawley rats

In order to investigate in utero morphological effect of hydroxyurea (HU) in Sprague-Dawley rats, HU was intraperitoneally injected to pregnant Sprague-Dawley rats at a dose of 100 or 200 mg/kg/day during the organogenetic period (days 9-12 of gestation). A dose of 200 mg/kg/day induced growth retardation, high mortality and high incidence of malformations, although a dose of 100 mg/kg/day produced no adverse effects in the next generation. In the HU 200 mg/kg/day group the incidence of malformations in pups at 4 days of age was low as compared with that in fetuses and pups at 21 days of age. Increasing perinatal mortality in fetuses and pups due to severe central nervous system (CNS) malformations and disappearance of some cases of ventricular septal defect after delivery were considered as the possible causes to induce difference in malformation rate in various stage of development. Latent effect on the development of CNS malformations was observed between 4 and 21 days of age. There was no sex difference in teratogenic effect. These findings were compared with those in Wistar rats exposed to HU 200 mg/kg/day. The incidence of perinatal malformations and the stillbirths were significantly higher in the Wistar rats as compared with those in the Sprague-Dawley rats. In addition, such morphological effects of HU as the exencephaly, dilatation of lateral ventricle, anophthalmia, cleft palate and micrognathia are less severe in Sprague-Dawley rat fetuses than in Wistar rat fetuses.     

The effect of in utero hypoxia on fetal heart and brain trace metals.

This study determined the effect of in utero hypoxia on fetal heart and brain pro- and antioxidant trace metals. Dunkin-Hartley guinea pigs (50–60 days gestation) were exposed to 1 h hypoxia (7% O₂/93% N₂) followed by 4 h reoxygenation in room air. Fetal hearts and brains were harvested and analyzed for copper, iron, magnesium and zinc. Fetal brain iron was significantly increased 28% after hypoxia and 35% by 1 h posthypoxia. Fetal brain magnesium demonstrated progressive decreases of 18% by 4 h posthypoxia. No significant effects of hypoxia were observed on heart trace metals. These results indicate that prooxidant metals may be increased and antioxidant metals may be decreased in posthypoxic fetal brain during a time when these tissues may be vulnerable to oxidative injury.     

Novel method for in vivo hydroxyl radical measurement by microdialysis in fetal sheep brain in utero.

Hydroxyl radical (.OH) is a reactive oxygen species produced during severe hypoxia, asphyxia, or ischemia that can cause cell death resulting in brain damage. Generation of .OH may occur in the fetal brain during asphyxia in utero. The very short half-life of .OH requires use of trapping agents such as salicylic acid or phenylalanine for detection, but their hydroxylated derivatives are either unstable, produced endogenously, or difficult to measure in the small volume of microdialysis samples. In the present study, we used terephthalic acid (TA), hydroxylation of which yields a stable and highly fluorometric isomer (excitation, 326 nm; emission, 432 nm). In vitro studies using .OH generated by the Fenton reaction showed that hydroxylated TA formed quickly (<10 s), was resistant to bleaching (<5% change in fluorescence), and permitted detection of <0.5 pmol .OH. In vivo studies were performed in fetal sheep using microdialysis probes implanted into the parasagittal cortex. The probe was perfused at 2 mul/min with artificial cerebrospinal fluid containing 5 mM TA, and samples were collected every 30 min. Fluorescence measured in 10 mul of dialysate was significantly greater than in the efflux from probes perfused without TA. High-performance liquid chromotography analysis showed that the fluorescence in dialysis samples was entirely due to hydroxylation of TA. Thus this study shows that it is possible to use TA as a trapping agent for detecting low concentrations of .OH both in vitro and in vivo and that low concentrations of .OH are present in fetal brain tissue and fluctuate with time.     

Accuracy of 2-hydroxyglutarate quantification by short-echo proton-MRS at 3 T: A phantom study

PurposeWe set out to investigate the potential confounding effect of variable concentration of N-acetyl-l-aspartate (NAA) and Glutamate (Glu) on measurement of the brain oncometabolite 2-hydroxyglutarate (2HG) using a standard MRS protocol. This issue may arise due to spectral overlap at clinical magnetic field strengths and thus complicate the usage of 2HG as a putative biomarker of gliomas bearing mutations of the isocitrate dehydrogenase (IDH) 1 and 2 genes.MethodsSpectra from 25 phantoms (50 mL falcon test tubes) containing a range of known concentrations of 2HG, NAA and Glu were acquired using a clinical 3 T scanner with a quadrature head coil, single-voxel point-resolved spectroscopy sequence with TE = 30 ms. Metabolite concentrations were estimated by linear combination analysis and a simulated basis set.ResultsNAA and Glu concentrations can have a significant confounding effect on 2HG measurements, whereby the negative changes in concentration of these metabolites typically observed in (peri)lesional areas can lead to under-estimation of 2HG concentration with respect to spectra acquired in presence of physiological levels of NAA and Glu.ConclusionThe confounding effect of NAA and Glu concentration changes needs to be considered: in patients, it may mask the presence of 2HG at low concentrations, however it is not expected to lead to false positives. 2HG data acquired using standard short echo-time MRS protocols should be considered with caution.     

Effects of in utero ultrasound exposure on the development of the fetal mouse testis.

The effect on the developing fetal testis of in utero exposure to 1-MHz, continuous-wave ultrasound in the spatial peak, temporal average intensity range 0.5-10 W/cm2 for durations of 400-30 sec on Day 9, 12, or 15 of gestation was determined. Results show that two subtle, yet potentially deleterious, effects occurred: a reduction in the Sertoli cell population and an apparent delay in the cessation of gonocyte mitosis. An increase was also seen in the number of fetal resorptions and stillborn pups per number of implantation sites in the exposed specimens as compared to the sham and cage controls. Because the reduction in testis weight was proportional to decreased body weight and because there was no difference in Sertoli cell numbers due to day of treatment, the testicular effects may reflect a generalized delay in growth. Whether this effect of ultrasound on fetal testis will be translated into an equal reduction in germ cell numbers in the adult testis remains to be determined.     

Deformation and recovery of cartilage in the intact hip under physiological loads using 7 T MRI

Accurate measurement of cartilage deformation in loaded cadaver hip joints could be a valuable tool to answer clinically relevant research questions. MRI is a promising tool, but its use requires an understanding of cartilage deformation and recovery properties in the intact hip. Our objective was to answer the following questions: (1) How long does it take for hip cartilage to reach a deformed steady-state thickness distribution under simulated physiological load, and how much does the cartilage deform? (2) How long does it take for hip cartilage to return to the original cartilage thickness distribution once the load is removed?MethodsFive human hip specimens were axially loaded to 1980 N in a 7 T MR scanner and scanned every 15 min throughout loading. One specimen was scanned every hour throughout recovery from load. One repeatability specimen was loaded and scanned every day for 4 days. Hip cartilage was segmented as a single unit and thickness was measured radially.ResultsThe hip cartilage reached a steady-state thickness distribution after 225 min of load, and 16.5 h of recovery. Mean strain after 225 min of load was 30.9%. The repeatability specimen showed an average day-to-day change in mean cartilage thickness of 0.10 mm over 4 days of data collection. The amount of deformation (0.96 mm) was far greater than the image resolution (0.11 mm) and error due to repeatability (0.10 mm).ConclusionUsing an ex vivo model, this method has potential for assessing changes in hip cartilage strain due to injury or surgical intervention.     

Fructose-1, 6-bisphosphatase in human fetal brain and liver during development

Activity of fructose-1,6-bisphosphatase (EC 3.1.3.11), one of the key gluconeogenic enzymes, was measured in human fetal brain and liver during development. Fructose-1,6-bisphosphatase was distributed throughout the different regions of the brain. In contrast to the partially purified enzyme from the brain, the liver enzyme was dependent on Mg²⁺ for maximal activity, EDTA, citrate, oleate and linoleate were stimulatory, whereas 5′-AMP inhibited the activity of the liver enzyme.     

Effects of hyperphenylalaninemia in the fetal stage on the postnatal development of fetal rat brain

The effect of exposure at different prenatal stages to maternal hyperphenylalaninemia (HyPhe) on the somatic and neurological development of fetuses in rats was studied, with special respect to the change of relevant enzyme activities in the brain. While evident somatic damage was found only in the fetuses exposed to maternal HyPhe at a last stage of gestation, distinct mental retardation seemingly due to some irreversible damage to the brain was observed in all the treated fetuses regardless of the timing of exposure, and a significantly reduced activity of 2, 3-cyclic nucleotide 3-phosphohydrolase (CNPase), a marker enzyme of myelin, was confirmed in the mantle region of the brain.Dedicated to Professor Yasuzo Tsukoda.     

Regulation of rabbit fetal glycogen: effect of in utero fetal decapitation on the metabolism of glycogen in fetal heart, lung, and liver

To understand the control mechanisms involved in the regulation of fetal glycogen, we have studied the effect of in utero fetal decapitations on glycogen metabolism in rabbit fetal heart, lung, and liver. In utero fetal decapitations were performed between days 18 and 21 of gestation. Two to four fetuses on one side of the horn were decapitated. Fetuses were delivered between days 23 and 26 or between days 28 and 30 of gestation. Fetal heart, lungs, and liver were analyzed for DNA, protein, glycogen, glycogen synthase (I and D forms), glycogen phosphorylase (a and b forms), phosphofructokinase, pyruvate kinase, and lactic dehydrogenase. In fetal heart and lung, no difference was observed in any of the above measurements in the intact and decapitated fetuses. In contrast, fetal liver does not appear to develop the glycogen system as indicated by the very low levels of glycogen (0.02 mg/mg DNA) in decapitated fetuses as compared with intact fetuses (0.4 mg/mg DNA). Similarly the levels of glycogen synthase and phosphorylase were two to three times lower in livers from decapitated fetuses as compared with the livers from intact fetuses. The three enzymes phosphofructokinase, pyruvate kinase, and lactic dehydrogenase were not affected by fetal decapitation in all three tissues. These results indicate that the fetal hypothalamic-pituitary-adrenal (thyroid) axis is not required at least after day 18 of gestation for the normal accumulation and subsequent utilization of glycogen in fetal heart and lungs, while it is an absolute requirement for the development of the fetal liver glycogen system.(ABSTRACT TRUNCATED AT 250 WORDS)     

Analysis of expression of CD2, CD3, and T cell antigen receptor molecules during early human fetal thymic development

To define early stages of T cell maturation during human fetal thymic development, we have used mAb reactive with CD2, CD3, and TCR molecules in indirect immunofluorescence assays on a series of early human fetal thymic specimens. Using a technique of quantitating the relative proportions of fluorescent-positive cells present in tissue sections, we found at 8.5 wk of gestational age after arrival of CD7+ T cell precursors into the thymic rudiment, 60% of thymic CD7+ cells were CD2+, 4% were CD3+ and none was TCR-delta+ or TCR beta+. Moreover, cells reactive with anti-CD2 antibodies against T11(2) and T11(3) epitopes of CD2 as well as thymic stromal cells expressing the CD2 ligand, lymphocyte function associated Ag-3, were also present at 8.5 wk. From 9.5 wk to birth TCR beta+ cells increased to include greater than 90% of all CD7+ cells while TCR-delta+ cells fell from a peak of 11% of CD7+ cells at 9.5 wk to 1% of CD7+ cells at birth. These data suggest that epitopes of CD2 molecules are expressed early on during fetal thymic development. Moreover, these data suggest that CD7+, CD2+, cytoplasmic CD3+ T cell precursors in man give rise to both TCR-delta+ T cells as well as to T cells expressing TCR-alpha beta.     

MRI osteitis predicts cartilage damage at the wrist in RA: a three-year prospective 3T MRI study examining cartilage damage

Introduction

Cartilage damage impacts on patient disability in rheumatoid arthritis (RA). The aims of this magnetic resonance imaging (MRI) study were to investigate cartilage damage over three years and determine predictive factors.

Methods

A total of 38 RA patients and 22 controls were enrolled at t = 0 (2009). After 3 years, clinical and MRI data were available in 28 patients and 15 controls. 3T MRI scans were scored for cartilage damage, bone erosion, synovitis and osteitis. A model was developed to predict cartilage damage from baseline parameters.

Results

Inter-reader reliability for the Auckland MRI cartilage score (AMRICS) was high for status scores; intraclass correlation coefficient (ICC), 0.90 (0.81 to 0.95) and moderate for change scores (ICC 0.58 (0.24 to 0.77)). AMRICS scores correlated with the Outcome MEasures in Rheumatoid Arthritis Clinical Trials (OMERACT) MRI joint space narrowing (jsn) and X-Ray (XR) jsn scores (r =0.96, P < 0.0001 and 0.80, P < 0.0001, respectively). AMRICS change scores were greater for RA patients than controls (P = 0.06 and P = 0.04 for the two readers). Using linear regression, baseline MRI cartilage, synovitis and osteitis scores predicted the three-year AMRICS (R² = 0.67, 0.37 and 0.39, respectively). A multiple linear regression model predicted the three-year AMRICS (R² = 0.78). Baseline radial osteitis predicted increased cartilage scores at the radiolunate and radioscaphoid joints, P = 0.0001 and 0.0012, respectively and synovitis at radioulnar, radiocarpal and intercarpal-carpometacarpal joints also influenced three-year cartilage scores (P-values of 0.001, 0.04 and 0.01, respectively).

Conclusions

MRI cartilage damage progression is preceded by osteitis and synovitis but is most influenced by pre-existing cartilage damage suggesting primacy of the cartilage damage pathway in certain patients.