ABSTRACT Achondroplasia, a form of short stature with short limbs, is the most com- mon disease among osteochondrodysplasia. The growth pattern of patients with achondroplasia is unique compared with the normal standard. At birth, patients’ heights are within normal limits and height velocity is normal during the first year in most patients. There- after, it declines to the 3 percentile line and remains low until 8 years of age. The peak height velocity is much lower during puberty in these patients than in the normal and contributes to short stature in achondroplasts. Extremely short stature lowers quality of life, therefore, various medications have been tried to promote growth in achondroplasts but in vain. GH is now produced in sufficient quantity utilizing recombinant DNA tech- nique. Since encouraging results have been obtained in the GH treatment of various kinds of short stature without GH deficiency, e.g., Turner’s syndrome, intrauterine growth retardation, non-endocrine short stature, etc., achondroplasia has been also considered as a candidate for GH treatment. There have been only a few studies on GH treatment in achondroplasia and the number of subjects studied is small. However, satisfactory growth-promoting effects have been demonstrated in these studies although observation periods were short and side effects have not been reported. Further studies are necessary to confirm the optimal dosage and administration method on final height and side effects in long-term use of GH.
ABSTRACT Using Chinese hamsters heterozygous for inversions of chromosomes 1 or 4 [INV( 1)37Idr and INV(4)Idr], as well as karyotypically normal animals, interchromoso- ma1 effects on meiotic disjunctions were investigated by chromosomal analysis of the meiotic cells and one-cell conceptuses. The mean frequency of nondisjunction at the first meiosis in five normal +/+ males was calculated at 1.28%, by doubling the frequency (0.64%) of hyperhaploid second meiotic (MII) cells, and there was no significant difference in the frequency among individuals. Among males heterozygous for INV(1)37Idr or INV(4)25Idr inversion, the frequencies of hyperhaploid cells with an extra inversion-unrelated chromosome were 0.52% and 0.43%, respectively, which were not significantly different from the frequency of hyperploid MI1 cells in +/+ males (0.52%). In one-cell conceptuses obtained from crosses between karyotypically normal females and males heterozygous for INV( 1)37Idr or INV(4)25Idr, 1.18% and 1.22% of conceptuses had an extra inversion-unrelated chromosome, respectively. The frequency of nondisjunction during meiotic divison in males heterozygous for these inversions was not significantly different from that in controls. The results therefore suggest that the presence of inversions in meiotic cells exerts no influence on disjunctions of normal bivalents and MI1 chromo- somes unrelated to the inversions.
ABSTRACT Congenital humero-radio-ulnar synostosis (HRUS) is a rare malformation. Some cases are hereditary in origin and some are sporadic. We report on a sporadic case of HRUS. A patient with HRUS is described who had constriction ring on the left upper limb and flexion contracture of the wrist joint and fingers. There was no range of motion nor crease at the elbow joint. Hypoesthesia was noted at the distal part of the ring of the upperarm as she did not respond to pin-prick. But circulatory failure like cyanosis or congestion was not seen on the extremity. No operation was performed to release the constrictive ring because it was not so deep. Only splint was applied to correct flexion contracture of the thumb, middle finger and ring finger. Three months later, examination of the thumb and fingers showed full extention. The sense to pain by pin-prick has been improved as the ring on the upperarm shallowed. A minor ischemic change may have been caused by the ring and followed by the contracture and the sensory disturbance. Synostosis also may have been related with the ring.
ABSTRACT This study was conducted to examine the effects of concanavalin A (Con A) on rat neurulation. Con A was injected intravenously to pregnant rats at a single dose of 5, 10, or 20 mgkg between gestational days (GD) 7.5 and 10.0, and the embryos were macroscopically examined on GD 1 1.5. Con A induced a high mortality rate, the treatment with 10 and 20 mgkg on GD 9.5 was completely lethal. Con A caused a high incidence of neural tube defects (NTD), the incidence in the 10 mgkg on GD 8.0 and 8.5 groups and in the 20 mgkg on GD 8.0, 8.5 and 9.0 groups being significantly higher than that in the control group. Histological evaluation revealed that Con A inhibited neural tube expansion and altered neural crest cell shape. In the Con A-treated embryos, the stratified structure of the neuroepithelium was irregular and its extracellular space was expanded. In rat embryos from intact dams, the distribution of receptors for Con A was demonstrated histochemically on the cell surfaces around neurulation sites between GD 8.5 and 10.5, but not on GD 7.5. These findings indicate that Con A bound around the neurulation sites in rat embryos may disturb the cell-cell communication required to form the neural tube, resulting in NTD.
ABSTRACT Embryotoxicity and teratogenicity of cadmium (Cd) and modulation of its effects by N-acetyl-L-cysteine (NAC) were evaluated in mice. Pregnant ICR mice were intraperitoneally injected with 3.5 mgikg of CdC12 on day 10 or I1 of gestation (vaginal plug = day 0). Pregnant mice were pretreated with 160 mgkg of NAC intravenously 2 hours before dosing with CdC12. Pregnant mice were killed on day 17 of gestation. Fe- tuses were examined for external malformations, especially limb malformations, cleft pal- ate and abnormal palatal rugae. There was little difference in body weight gain of dams during the gestation period in the groups treated with NAC plus Cd as compared with the groups treated with Cd alone. Pretreatment with 160 mgkg of NAC decreased the fetal mortality, incidence of cleft palate and abnormal palatal rugae induced by Cd on day 11. On day 10, pretreatment with NAC decreased the incidence of Cd induced abnormal palatal rugae. These results clearly indicate that NAC exerts protective effects against embryotoxicity and teratogenicity of Cd
ABSTRACT The prevalence and death rates for microcephaly were analyzed using Japa- nese Vital Statistics for the period 1969-1992. The prevalence rate was 0.23 per 10,000 births in 1979 and the overall rate was 0.20 during the period 1979-1982. The prevalence rate slightly increased with paternal age, whereas the rate remained constant with maternal age except the 40 years age group. Overall death rates per 100,000 population under 20 years of age were 0.094 for males and 0.090 for females. In both sexes, the death rate gradually decreased with age. The proportion of deaths with microcephaly under 5 years old was 78% and under 20 years old was 97%. Geographical variations in the death rate of microcephaly were observed with the highest death rate in Tottori Prefecture (0.245), and the lowest in Fukui Prefecture (0.018). The mean age at death in microcephalics increased from about 3 years in 1969-1971 to 13 years in 1990-1992 for both sexes.
ABSTRACT Effects of folic acid (FA) and folinic acid (FNA) on the embryotoxicity of pyrimethamine (PYR), an antifolate drug, were examined in mice. PYR and FA were administered orally, and FNA was injected intraperitonially for 7 days from day 9 to 15 of pregnancy. The incidence of embryotoxicity including intrauterine deaths and mal- formations, was 33.5 % in the PYR 50 mg/kg/day group. However, all the fetuses were resorbed in the PYR 50 + FA 50 mgkg/day group, and FA potentiated the embryotoxicity of PYR. On the contrary, FNA reduced the embryotoxicity of PYR (PYR 50 + FNA IOmg/kg/day; 8.5%). Plasma concentrations of PYR and 5-methyltetrahydrofolic acid (5MF), a principal form of folate in plasma, were determined after single oral administration of PYR 50 mgkg with or without FA 50 mgkg to non-pregnant mice. Plasma 5MF concentration decreased drastically in the group receiving PYR with FA, compared with the PYR alone group. The pharmacokinetics of PYR were not affected by co-administration of FA. Therefore, we consider that the potentiated embryotoxicity of PYR by oral FA results from a decrease of plasma 5MF concentration in dams.