The thanatophoric dwarf. A report on two cases

Two cases of thanatophoric dwarfism are presented. At external physical examination this anomaly is not readily distinguishable from achondroplasia and other forms of congenital disproportionate dwarfism. Radiologically, however, characteristic skeletal changes are demonstrable. The diagnosis can be made in utero. The clinical course is invariably fatal. The hereditary aspects, of importance for genetic counseling of parents, are still unexplained. The patients discussed show the typical thanatophoric skeletal changes in combination with a form of synostosis, i.e. bilateral radioulnar synostosis in one case, and synostosis of the coronal sutures and the lambdoid suture in the other. Emphasis is placed on the importance of radiological examination in cases of unexplained hydramnion and perinatal death.     

Naloxone antagonizes narcotic self blockade of emesis in the cat

Morphine, levorphanol, fentanyl and methadone given by intracerebroventricular (i.c.v.) injection blocked the vomiting response to a standard emetic test dose of apomorphine subsequently injected i.c.v. Of these narcotics, only morphine initially evoked vomiting. Systemic pretreatment with naloxone (5 mg/kg i.p. or i.v.) uniformly abolished the antiemetic activity of all the represented narcotic agents, moreover, naloxone thus administered was followed consistently by emetic responses to those narcotics which separately failed to evoke vomiting. When naloxone was injected i.c.v. in addition to being given systemically, both antiemetic and emetic activities of the narcotic agents were essentially abolished, whereas apomorphine continued to evoke vomiting. In the presence of systemic naloxone, given to counteract self-blockade of vomiting, the narcotics were shown to induce vomiting through excitation of the medullary emetic chemoreceptor trigger zone and emetic receptor tolerance as well as cross-tolerance developed acutely. The present differentiation by naloxone of the emetic and antiemetic properties of narcotic agents placed in the cerebrospinal fluid indicates that the opposing narcotic actions are exercised at different sites in the brain and that the narcotic receptor specificity of the chemoreceptor trigger zone does not encompass the emetic action of apomorphine.     

Anti-self receptors. IV. H-2-restricted receptors on thymocytes recognize carbohydrate structures on target cells

Rosetting between thymocytes and autologous erythrocytes in mediated by receptors on thymocytes that primarily recognize self H-2L molecules on erythrocytes. This paper describes preliminary attempts to chemically characterize the receptor and acceptor molecules involved in this H-2-restricted interaction. On the basis of sugar inhibition studies and the sensitivity of the receptors to protease and glycosidase treatments it appears that a protein receptor on thymocytes recognizes the carbohydrate portion of a glycoprotein on erythrocytes. Furthermore, the thymocyte receptor appears to recognize terminal D-galactose, D-mannose and sialic acid residues on a branched-chain carbohydrate structure on erythrocytes, with mouse strains of different H-2 haplotype expressing carbohydrate structures that differ in the linkage of these three terminal sugars. These findings indicate that H-2-restricted carbohydrate-protein interactions can occur between cells, a conclusion with important theoretical implications.     

Echinocytosis induced by haemodialysis

BACKGROUND: Haemodialysis, widely used to treat patients with renal failure, is not always well tolerated. Different mechanisms have been postulated for this. We analyzed the influence of haemodialysis on erythrocyte morphology and blood rheology. METHODS: Twenty-two haemodialysed patients were studied immediately before haemodialysis, after 30 min, and at the end of haemodialysis with biocompatible membranes. Haematological routine was measured, the erythrocyte morphology was assessed on glutaraldehyde-fixed cells and blood viscosity was determined. RESULTS: Erythrocytes underwent various degrees of echinocytic shape transformation after 30 min of haemodialysis, which was completely reversible at the end. In a repetition of the investigations during a subsequent haemodialysis other patients were affected. A plasmatic factor caused echinocytosis since the incubation of control erythrocytes in patients plasma induced a similar, even more marked shape transformation and, vice versa, patient echinocytes regained a discocytic shape when incubated in buffer. The degree of echinocytosis was related to an increased blood viscosity at high shear rates (r=0.800, P<0.01). Echinocytosis was not accompanied by obvious clinical reactions. CONCLUSIONS: Reversible echinocytosis and an increase in blood viscosity is often seen during haemodialysis, which may affect the circulation in patients at risk.     

Developmental toxicity of clarified slurry oil, syntower bottoms, and distillate aromatic extract administered as a single oral dose to pregnant rats

Clarified slurry oil (CSO), syntower bottoms (STB), and distillate aromatic extract (DAE) are refinery streams produced by processing crude oil. Each of these refinery streams is rich in both hydrocarbons having carbon numbers of C20 or greater and polycyclic aromatic compounds. Available data indicate that some refinery streams are developmentally toxic (manifested primarily as increased embryolethality and growth retardation) by the dermal route of exposure. However, there is no conclusive evidence for their being teratogenic. The present studies were designed to further explore the suspected teratogenic potency of refinery streams while at the same time limiting embryolethality. To profile teratogenic effects as a function of gestation day, pregnant rats received a single oral dose (2000 mg/kg) of CSO, STB, or DAE on one of gestation days (GD) 11-14; DAE and STB were also administered on GD 15. To profile effects as a dose response function, rats received a single oral dose of CSO, DAE, or STB on GD 12 at 125, 500, and 2000 mg/kg. Control animals were similarly treated but were administered tap water. On GD 20, dams were necropsied and the fetuses evaluated for normal development. In general, evidence of maternal toxicity (i.e., decreased body weight gain, decreased thymus weight) was observed at doses greater than or equal to 500 mg/kg. For each refinery stream tested, the incidence of resorption was greatest on GD 11. A common pattern of fetal malformations was observed for all of the refinery streams tested and included cleft palate, diaphragmatic hernia, and paw and tail defects. The incidence and type of malformation observed were influenced by the gestation day of exposure. The incidences of external and skeletal malformations were greatest on GD 11 and 12 for fetuses exposed to CSO; on GD 13 and 14, the incidence of malformation was comparable for CSO- and STB-exposed fetuses. The incidence of visceral anomalies was greatest on GD 11-13 for fetuses exposed to CSO and STB; on Gestation D 14, the incidence was comparable for each of the refinery streams tested. In general, the ability to produce adverse effects on development was greatest for CSO and least for DAE. Effects produced by STB were comparable to or less severe than those observed for CSO.