Genetic Testing for Huntington's Disease in Parkinsonism

The study was conducted to find out Huntington's disease (HD) by genetic analysis from those presenting with parkinsonism in the Neurology department of Mymensingh Medical College & Hospital. A sample of about 5ml blood was collected by veni puncture in EDTA tube with informed consent from 9 patients & 7 healthy individuals after approval of the institutional ethics committee for genetic study. The neurological disorder along with a complete history and physical findings were recorded in a prescribed questionnaire by the neurologists of Mymensingh Medical College & Hospital. Extraction of genomic DNA from the venous blood using FlexiGene DNA kit (Qiagen, Japan) was performed in Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh, Bangladesh. The extracted DNA was stored and accumulated and then these DNA were sent to Division of Clinical Genetics, Department of Medical Genetics, Osaka University Medical School, Suita, Osaka 565 0871, Japan for PCR and further analysis. PCR amplification of the CAG repeat in the 1T15 gene was performed with primers HD1 and HD3. HD PCR products revealed the DNA product of about 110bp (no. of CAG repeats=21) to 150bp (no. of CAG repeats=34) in both healthy individual and suspected PD patient DNA.

Identification of ter94, Drosophila VCP, as a modulator of polyglutamine-induced neurodegeneration

We have successfully generated a Drosophila model of human polyglutamine (polyQ) diseases by the targeted expression of expanded-polyQ (ex-polyQ) in the Drosophila compound eye. The resulting eye degeneration is progressive and ex-polyQ dosage- and ex-polyQ length-dependent. Furthermore, intergenerational changes in repeat length were observed in homozygotes, with concomitant changes in the levels of degeneration. Through genetic screening, using this fly model, we identified loss-of-function mutants of the ter94 gene that encodes the Drosophila homolog of VCP/CDC48, a member of the AAA+ class of the ATPase protein family, as dominant suppressors. The suppressive effects of the ter94 mutants on ex-polyQ-induced neurodegeneration correlated well with the degrees of loss-of-function, but appeared not to result from the inhibition of ex-polyQ aggregate formation. In the ex-polyQ-expressing cells of the late pupa, an upregulation of ter94 expression was observed prior to cell death. Co-expression of ter94 with ex-polyQ severely enhanced eye degeneration. Interestingly, when ter94 was overexpressed in the eye by increasing the transgene copies, severe eye degeneration was induced. Furthermore, genetical studies revealed that ter94 was not involved in grim-, reaper-, hid-, ced4-, or p53-induced cell death pathways. From these observations, we propose that VCP is a novel cell death effector molecule in ex-polyQ-induced neurodegeneration, where the amount of VCP is critical. Control of VCP expression may thus be a potential therapeutic target in ex-polyQ-induced neurodegeneration.

Efferents from the optic tectum to the brain stem in the Japanese quail (Coturnix japonica). Anterogradely biocytin method

Efferents from the optic tectum to the brain stem in the Japanese quail (Coturnix japonica) were studied with the anterogradely biocytin method. After injection of biocytin into the ipsilateral optic tectum, labeled terminals were seen in the rotund nucleus (Rt), neuropil part of the ventral lateral geniculate nucleus (GLnv), principal part of the dorsal lateral geniculate nucleus, lateral part of the dorsolateral thalamic nucleus, triangular nucleus (T), superficial parvocellular nucleus (SPC), pretectal nucleus, pretectal area (PA), subpretectal nucleus, central gray matter (GC), isthimo optic nucleus (ION), magnocellular and parvocellular parts of the isthimo nuclei (Imc and Ipc), semilunar nucleus (SLu), lateral and medial pontine nuclei and reticular formation (FRM) of the medulla, ipsilaterally. Labeled fibers were seen in the septomesencephalic tract nucleus, FRM, interstitio-paraetecto-subpraetectal nucleus, and the dorsal and ventral tectoreticular tracts (TRd and TRv). In the contralateral brain stem, labeled terminals were seen in the Rt, T. FRM, PA and paramedian nucleus. The contralateral terminals were remarkably fewer than those of the ipsilateral side. The present findings of the labeled terminals of the SPC and the GC at the level of the mesencephalic nucleus of the trigeminal nerve (MnT), and the topographic projection from optic tectum to the Rt in the thalamus, were original observations in the avian. The labeled terminals in the GLnv, Ipc, Imc and ION showed topographical projections from the optic tectum. Pathways to the contralateral brain stem were via the commissure posterior, ventral supraoptic decussation, and the predorsal bundle. The present results suggest that tectofugal impulses in the quail relate to various functions with special relation to the function of the GC at the level of the MnT as well as a visual function.

Neurotoxic effects of 2,5-hexanedione on rapidly growing unmyelinated peripheral nerve axons of a rat fetus: dose-effect relationship

To investigate the potential neurotoxicity of 2,5-hexanedione (2,5HD) on developing axons we examined peripheral nerves of rat fetuses. Pregnant female Sprague-Dawley rats were injected subcutaneously with 680 mg/kg of 2,5HD once a day from Day 12 of gestation (GD12) to GD16 in one group and with 340 mg/kg of 2,5HD once a day from GD12 to GD20 in the other group. On GD20 live fetuses were removed from the uteri and their sciatic nerves were examined morphologically. By electron microscopical observations, affected nerves revealed axons which were aggregated and fused together, but there were no axons aggregated with neurofilaments. The diameter distributions of axons revealed an increase in the number of small-size axons in the nerves of the 340 mg/kg group and showed an enlargement of part of the axons in the nerves of the 680 mg/kg group, suggested by the appearance of a second peak at a diameter larger than that of the first peak.

Effects of sodium bicarbonate and ammonium chloride on the incidence of furosemide-induced fetal skeletal anomaly, wavy rib, in rats

Furosemide produces fetal wavy ribs when administered to pregnant rats during late gestation. The compound is also known to produce metabolic alkalosis in laboratory animals and man. In order to evaluate the effect of furosemide on maternal blood pH, Crj:CD(SD) female rats received an oral administration of 150 or 200 mg/kg of furosemide by gavage on day 16 of gestation and were bled at 4 hr post-dose. Compared to an average pH of 7.39 in control females, there was a significant elevation in blood pH in these furosemide-treated females (average pH of 7.44 to 7.48). When 2% sodium bicarbonate was provided in the drinking water for females treated with 150 mg/kg of furosemide, there was a further rise in maternal blood pH (7.52) compared to females treated with furosemide alone. Associated with this elevation in maternal blood pH was a marked increase in the incidence of fetal wavy ribs (87.6% compared to 27.6%). When females treated with 200 mg/kg of furosemide were provided with 0.5% ammonium chloride, furosemide-induced maternal alkalosis was corrected (pH decreased to 7.35) and there was a reduction in the incidence of fetal wavy ribs (7.0% compared to 37.2%). In addition, maternal blood pH among individual females was positively correlated with the incidence of fetal wavy ribs (r = 0.714). These results suggest that maternal metabolic alkalosis is involved in the pathogenesis of furosemide-induced wavy ribs.

Neurotoxic effects of 2,5-hexanedione on growing peripheral nerve axons of rat fetuses

Peripheral nerves of rat fetuses were used to investigate the potential neurotoxicity of 2,5-hexanedione (2,5-HD) on developing axons. Pregnant female Sprague-Dawley rats were injected subcutaneously with 680 mg/kg of 2,5-HD once a day from day 12 of gestation (GD12) through GD16. On GD20 live fetuses were removed from the uterus, and the sciatic nerves were examined morphologically. Upon electron-microscopy affected nerves showed axons which were aggregated and fused together; the number of large axons was increased, but there were no axons aggregated with neurofilaments.

Relationship between the development of the gubernaculum and the testicular descent in the rat fetus: macroscopic and light and electron microscopic observation

The gubernaculum consists of the gubernacular cord connected with the vas deferens and the gubernacular bulb connected with the retroabdominal wall. The cord was first distinguished on day 15 of gestation. Its length reached the peak on day 16, followed by a reduction until day 18 to be almost constant thereafter. The bulb was first distinguished on day 16, and its length was steadily increased toward term. The testis began to descend with a reduced length of the cord. By day 19, the testis descended close to the caudal part of the bulb by the sharp bending of the cord. Microscopically, the bulb consisted at first of a centrally located mesenchymal mass and of a covering layer of myoblasts. Thereafter, the mesenchymal mass was gradually shifted toward the cranial part of the bulb, trailing loose mesenchymal tissue in the caudal part of the bulb. On day 19, the mass was decreased in cell population but increased in amount of collagen fibers. It is suggested that the testicular descent starts on day 16 together with the commencement of shortening of the gubernacular cord and enlargement of the gubernacular bulb.