Naam Kariv

Experimental intrauterine growth retardation alters renal development

Abstract Vascular placental insufficiency is considered a common pathogenic factor in human intrauterine growth retardation (IUGR), resulting in small-for-gestational-age, asymmetric newborns. IUGR neonates experience higher morbidity and mortality rates, as well as a possible contribution towards late sequelae, such as hypertension, and cardiovascular disease in adulthood. To simulate vascular placental insufficiency, an experimental rabbit IUGR model was used. Intrauterine growth retardation was achieved by ligation of 25–30% uteroplacental vessels of half of the fetuses during the last third of gestation. Ischemic fetuses were significantly small, asymmetric, and had a disproportionately small body with a relatively large head. The kidneys from all groups were analyzed for relative estimated glomeruli number (REGN) using an unbiased blind design. The glomeruli number was significantly reduced in the asymmetric IUGR rabbit fetuses, probably due to decreased renal vascular supply. Our results support the concept that the reduced number of glomeruli may contribute to impaired renal function, thus predisposing to neonatal renal dysfunction and late sequelae, such as adult hypertension. This study emphasizes the clinical importance of early IUGR diagnosis and prevention.

NAP Enhances Neurodevelopment of Newborn Apolipoprotein E-Deficient Mice Subjected to Hypoxia

Perinatal hypoxic injury is associated with significant neonatal morbidity and long-term neurodevelopmental complications. NAP, a peptide derived from ADNP (activity-dependent neuroprotective protein), has previously shown neuroprotective abilities in various adult animal models. To evaluate its neuroprotective role in neonatal hypoxic-ischemic injury, we evaluated the neurodevelopmental outcome in apolipoprotein E (ApoE)-deficient (knockout) mice (a breed prone to brain damage during hypoxic insult) exposed to postnatal global hypoxic damage with and without treatment with NAP. ApoE-deficient (n = 80) and control (C57B6) mice pups (n = 81) were exposed to postnatal global hypoxia (35 min of 8% O2 within 24 h of birth) or room air with or without subsequent subcutaneous NAP treatment during postnatal days 1 to 14. Pups were then evaluated for neonatal motor reflex attainment, spatial learning ability in the Morris water maze, and locomotor open-field activity. The C57B6 and ApoE-deficient anoxic groups showed significantly slower achievement of neonatal reflexes, diminished locomotor activity, and diminished spatial learning ability compared with their control groups. This was more pronounced in the anoxic ApoE-deficient pups. NAP treatment had a pronounced effect on neurodevelopmental outcome in both breeds, particularly in the ApoE-deficient mice. ApoE-deficient and control mouse pups exposed to postnatal hypoxia and treated with NAP showed improvement in neurodevelopmental outcome compared with nontreated mice pups. ApoE-deficient mice show a greater susceptibility to hypoxic damage and better response to NAP treatment.

The pregnant spontaneously hypertensive rat as a model of asymmetric intrauterine growth retardation and neurodevelopmental delay.

Introduction. Hypertension in pregnancy and vascular placental insufficiency are considered common pathogenic factors in human intrauterine growth retardation (IUGR). IUGR neonates experience higher mortality, and the surviving infants have a higher incidence of neurological and intellectual impairment. Methods. To mimic this condition, we used pregnant spontaneously hypertensive rats (SHR) and performed biometric measurements on Embryonic Day 20, postnatal developmental reflexes, and locomotor activity evaluations. Results. SHR fetuses had significant decreased body weight compared to the Wistar-Kyoto control fetuses (1.51 ± 0.02 g vs. 2.05 ± 0.01 g, respectively; p < 0.0001), and were relatively microcephalic (2.86 ± 0.04 cm vs. 3.3 ± 0.03 cm, respectively; p < 0.0001). Their cephalization index (head circumference/body weight) was increased (1.88 ± 0.03 vs. 1.62 ± 0.02, respectively; p < 0.0001), indicating a “brain-sparing” process. The disproportional ratio indicated that the IUGR type in this model is asymmetric. The SHR pups exhibited a significant (p < 0.04) neurodevelopmental delay in the acquisition of neonatal reflexes (righting, negative geotaxis, placing), but they spontaneously caught up with the control pups after approximately 10 days. On Day 30, the SHR pups exhibited significantly increased walking speed and distance and spent less time in quadrant than the controls (p < 0.002). Conclusion. We speculate that the model of pregnant SHR closely simulate human IUGR caused by hypertension in pregnancy and should enable investigation of mechanisms of hypertension-mediated placenta-vascular injury as well as provide a system for preclinical evaluations of future preventive neuroprotective treatments.

The effects of vascular intrauterine growth retardation on cortical astrocytes

OBJECTIVE We sought to determine the pathogenesis of neurodevelopmental impairments in survivors of intrauterine growth retardation (IUGR). METHODS We used an experimental rabbit vascular IUGR model. We ligated 25% of uteroplacental vessels (partial ischemia) of one-half of the fetuses on day 25 at the end of the third trimester. We then determined hemispheral DNA and protein levels, and used glial fibrillary acidic protein (GFAP) staining to count the labeled astrocytes at the superficial cortical layers. RESULTS Ischemic fetuses were significantly smaller than control fetuses and presented a disproportionately small body and a relatively larger head compared with the normal body/head ratio, confirming the study model as that of asymmetric IUGR. Hemispheral DNA was unchanged in IUGR fetuses, but they had decreased brain weight, hemispheral protein content, and a reduced number of mature (GFAP-positive) cortical astrocytes compared with control fetuses. CONCLUSION Vascular IUGR, as demonstrated in our asymmetric IUGR model, adversely affected brain growth, cell size, and cortical astrocytes maturation. In view of the neurotrophic and neuroprotective functions of astrocytes, a reduced number of mature astrocytes during this critical period of development may be implicated in the pathogenesis of the neurodevelopmental impairments observed in IUGR.

Gene-expression-based analysis of local and metastatic neuroblastoma variants reveals a set of genes associated with tumor progression in neuroblastoma patients

Metastasis is the primary cause of mortality in Neuroblastoma (NB) patients, but the metastatic process in NB is poorly understood. Metastsis is a multistep process that requires the coordinated action of many genes. The identification of genes that promote or suppress tumor metastasis can advance our understanding of this process. In the present study, we utilized a human NB xenograft model comprising local and metastatic NB variants, which was recently developed in our laboratory. We set out to identify molecular correlates of NB metastasis and to determine the clinical relevance of these molecules. We first performed genome‐wide expression profiles of metastatic and nonmetastatic NB variants that have an identical genetic background. We found that some of the proteins highly expressed in the metastatic NB variants are localized in the cytoplasm and endoplasmic reticulum. Other proteins are linked to metabolic processes and signaling pathways, thereby supporting the invasive and metastatic state of the cells. Subsequently, we intersected the differentially expressed genes in the human xenografted variants with genes differentially expressed in Stage 1 and Stage 4 primary tumors of NB patients. By using the same gene‐expression platform, molecular correlates associated with metastatic progression in primary NB tumors were identified. The resulting smaller gene set was clinically relevant as it discriminated between high‐ and low‐risk NB patients.

Telmisartan in the Treatment of Cohen-Rosenthal Diabetic Hypertensive Rats: The Benefit of PPAR-γ Agonism

The antihypertensive and hypoglycemic effects of telmisartan, which has dual angiotensin II antagonist-PPAR-γ agonist properties, was studied in Cohen-Rosenthal Diabetic Hypertensive rats (CRDH), a model in which hypertension, insulin resistance, and diabetes co-exist. CRDH, Cohen-diabetic rats (CDR), and SHR received telmisartan (3 mg/kg/day in drinking water) for five months. Telmisartan significantly lowered systolic and diastolic BP in SHR and CRDH, independent of body weight, and remained fairly constant in controls throughout the experiment. Blood glucose levels fell rapidly in the treated animals and remained steady in controls. Results indicate that telmisartan is a prototype of a new approach to treating coexisting diabetes and hypertension.

In vivo laser soldering of incisions in juvenile pig skins using GaAs or CO2 lasers and a temperature control system

Two temperature controlled laser soldering systems were compared, one based on a GaAs laser and the other on a CO2 laser. Both systems were used for bonding full thickness incisions. Methods: 47% bovine serum albumin (BSA) solder was used in the CO2 laser soldering experiments. BSA with 1.8 mg/ml Indocyanine Green (ICG) was used for the GaAs soldering experiments. In both cases the solder was applied onto cuts created in juvenile pig skin and an infrared fiberoptic system was used to monitor and control different temperature and time settings. Differences in tensile strength and wound reparative parameters were compared between GaAs laser, CO2 laser, and Dermabond glued incisions on the seventh day after the operation. Results: The tensile strength of CO2 laser-soldered and Dermabond glued incisions were found to be higher than that of the GaAs laser-soldered incisions. Histological study showed better and faster wound healing characteristics of the CO2 laser soldered incisions, as compared to the GaAs laser-soldered and glued incisions. Conclusions: Preliminary results of temperature controlled CO2 laser soldered incisions suggest a better wound reparative process over the temperature controlled GaAs laser soldered incisions. Laser soldering offers many advantages over gluing techniques.

A Preclinical Study ofEO-122, a New Lidocaine- Like Antiarrhythmic Drug

The 2,6-dimethylanilide of quinuclidine-3-carboxylic acid hydrochloride (EO-122), a new structural analog of lidocaine, has been shown to possess po tent antiarrhythmic activity in experimentally induced arrhythmias in animals. Restoration of normal sinus rhythm and suppression of ouabain-induced ar rhythmia in cats and dogs, and of coronary occlusion-induced arrhythmia in dogs, followed a single IV injection of 1-3 mg/kg, with an onset of 2 minutes and a duration of 20-240 minutes. Occlusion-induced arrhythmia was likewise suppressed after an oral dose of 10-20 mg/kg, with an onset of 11-65 minutes and a duration of 25-120 minutes. Under similar conditions, lidocaine was ei ther totally ineffective or of ultra-short duration. The bioavailability of EO-122 by the oral route exceeded 80% of the oral dose. Therapeutic blood concentrations were in the range 0.5-7 μg/ml. At about 5μg/ml there was a slight depression of cardiac function in the anesthe tized cat, but not in the conscious dog. In cats, complete A-V block occurred at concentrations of 60-70 μg/ml. The IV LDso in mice was 22 mg/kg, and in rabbits 8.5 mg/kg. No overt signs of neurotoxicity could be observed at any dose of EO-122. The pharmacokinetic profile of the drug fits a two-com partment open model, with t½ ≃ 150 min and Vd (ss) ≃ 1.5 1/kg.

CO 2 laser soldering of arteriotomy incisions in blood vessels of rats using a temperature-controlled fiber optic system

Background and objectives: Conventional methods for microvascular anastomosis are normally based on suturing, using special thin nylon sutures. These methods suffer from major drawbacks, which include: anastomosis, which is not watertight, and sutures or clips that cause an inflammatory response. In order to obtain better results, we introduced a procedure based on CO 2 laser soldering. We tested the system on arteriotomy incisions in rat blood vessels, in vivo. Materials and methods: We used a fiber optic based laser soldering system, with a temperature control capability. Arteriotomy incisions of lengths 4±1mm were performed on the femoral arteries of 48 wistar rats: 24 rats in the control group (suture) and 24 rats in the test group (laser soldering). We conducted two follow-up periods: 7 days and 21 days after the surgical procedure, for each group. Flow tests and histology examination were done in order to evaluate the quality of the procedures. Results: The patency rate was 84% for both groups, soldered and sutured. The sutured group showed a significant foreign body reaction (p < 0.05), which was not observed in the soldered group. We found no evidence of thermal damage in the soldered blood vessels. Conclusions: We can conclude that laser soldering is a less traumatic procedure, compared with the conventional suturing technique. It is potentially a faster technique and easier to master.

CO 2 temperature-controlled laser soldering of pig trachea incisions in vitro using flexible albumin bands

Resection of a segment of the trachea is a procedure applied for the removal of cervical tumors invading the trachea, or for the treatment of severe tracheal stenosis. The current method of anastomosis is based on multiple sutures. The main drawbacks of this method are: 1) A long procedure time, 2) An air leakage, and 3) An inflammatory response to the sutures. In this study we evaluated the feasibility and effectiveness of the use of temperature controlled CO2 laser soldering of incisions in pig tracheas in vitro. A transverse incision was made in a separated pig trachea. A flexible albumin band was prepared and was laser soldered with albumin solder to the outer surface of the trachea, covering the incision. The soldered trachea ends were sealed and the burst pressure was measured. In a series of in vitro experiments, the mean burst pressure was found to be 230 mm Hg. These preliminary results demonstrated that laser soldering using a flexible albumin band may be a useful method for sealing an incision in the trachea.