Specific antisera to C1r. Quantitation of C1r in normal and pathological human sera

Monospecific neutralizing and precipitating antisera to C1r, a subunit of the first complement component, were obtained. These antisera neutralized C1r activity in purified preparations and in macromolecular C1 and did not react with C1q or C1s. They formed one line of precipitation in the β-globulin region with normal human serum, C1^hu and C1r at various stages of purification. Using anti-C1r antiserum and a radial immunodiffusion technique, the concentration of C1r was determined in normal, SLE and RA sera. It was 101 μg/ml in normal sera and lower in sera of active SLE patients (69·7 μg/ml). No significant variations from normal were found in sera of SLE patients in periods of remission or in RA patients.     

Myosin VIIA gene: heterogeneity of the mutations responsible for Usher syndrome type IB

Usher syndrome is recognized as the most frequent cause of hereditary deaf-blindness. Usher syndrome type I (USH1), the most severe form of the disease, is characterized by profound congenital sensorineural deafness, constant vestibular dysfunction, and retinitis pigmentosa of prepubertal onset. This form is genetically heterogeneous and five loci (USH1A-E) have been mapped thusfar. However, only the gene responsible for USH1 B (which accounts for approximately 75% of USH1 cases) has been characterized. It encodes a long-tailed unconventional myosin, myosin VIIA, with a predicted 2215 amino acid sequence. Primers covering the complete myosin VIIA coding sequence as well as the 3' non coding sequence were designed, allowing direct sequence analysis of each of the 48 coding exons and flanking splice sites in seven patients affected by USH1. Four novel mutations were thereby identified. The possibility should now be considered of a sequence-based prenatal diagnosis in some of the families affected by this very severe form of Usher syndrome.      

Occurrence of infection with a parvovirus-like agent in children with sickle cell anaemia during a two-year period.

The occurrence of infection with a parvovirus-like agent during the period April 1979-May 1981 in children attending a single sickle cell clinic in London was investigated. Virus was detected in serum by counter-current immunoelectrophoresis (CIE) and immunoelectron microscopy (IEM). Viral antibody was detected by CIE and specific IgM antibody by an IgM-antibody capture assay. Of the 68 children studied nine presented in aplastic crisis and evidence of infection with the parvovirus-like agent at the time of the crisis was found in all nine. Eighteen of the other children were antibody-positive at some time during the study. In 11 children there was no evidence of recent infection; however, two of these had a history of aplastic crisis in previous years. The other seven seroconverted during the course of the study but did not show any haematological effects. Five of these had a primary infection, one appeared to have reinfection and in the seventh there were insufficient data to distinguish between the two. Possible explanations for the difference between those presenting with aplastic crisis and those with asymptomatic seroconversion are discussed.     

Guinea pig cytomegalovirus: Transplacental transmission

Summary A well characterized strain of guinea pig cytomegalovirus (GPCMV) was used to infect pregnant guinea pigs during various periods of pregnancy. Transplacental transmission of virus with invasion of the fetus was observed, even in some mothers with preinoculation evidence of GPCMV antibody. Fetal infection occurred during the middle third of pregnancy and GPCMV was isolated from many fetal tissues although histologic evidence of infection was not noted. During the last third, abortion of the pregnancy occurred in some animals.This report demonstrates that GPCMV may invade the fetus producing a sublethal, possibly mild infection which may be very similar to the usual type of CMV infection observed in the human newborn.