Vocal cord paralysis in postpoliomyelitis syndrome

Postpoliomyelitis syndrome is characterized by new neuromuscular symptoms, including weakness, developing years after recovery from acute polio. Bilateral vocal cord paralysis is presented as a new manifestation of this syndrome. Other clinical features of post-poliomyelitis syndrome in this report are discussed. The etiology of this syndrome is unknown, though attrition or immune-mediated destruction of collateral muscular innervation appears likely. The pathologic findings include scattered individual muscle fiber atrophy as well as evidence of chronic denervation and reinnervation. This form of motor deterioration is not life-threatening, but potentially may cause increasing disability in a large number of polio survivors. Proper supportive care of facial, laryngeal, and pharyngeal weakness is crucial in the management of these patients.

Inhibition of ribulose bisphosphate carboxylase assembly by antibody to a binding protein

We have developed an assay to monitor in vitro the posttranslational assembly of the chloroplast protein, ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). Most of the newly synthesized 55-kD catalytic ("large") subunits of this enzyme occur in a 29S complex together with 60- and 61-kD "binding" proteins. When the 29S complex is incubated with ATP and MgCl2 it dissociates into subunits, and the formerly bound large subunits now sediment at 7S (still faster than expected for a monomer). Upon incubation at 24 degrees C, these large subunits assemble into RuBisCO. The minority of newly made large subunits which are not bound to the 29S complex also sediment at 7S. When endogenous ATP was removed by addition of hexokinase and glucose, the dissociation of the 29S complex was inhibited. Nevertheless, the 7S large subunits assembled into RuBisCO, and did so to a greater extent than in controls retaining endogenous ATP. Thus the 7S large subunits are also assembly competent, at least when ATP is removed. Apparently, in chloroplast extracts, ATP can have a dual effect on the assembly of RuBisCO: on the one hand, even at low concentrations it can inhibit incorporation of 7S large subunits RuBisCO; on the other hand, at higher concentrations it can lead to substantial buildup of the 7S large subunit pool by causing dissociation of the 29S complex, and stimulate overall assembly. At both high and zero concentrations of ATP, however, antibody to the binding protein inhibited the assembly of endogenous large subunits into RuBisCO. Thus it appears that all assembly-competent large subunits are associated with the binding protein, either in the 7S complex or in the 29S complex. The involvement of the binding protein in RuBisCO assembly may represent the first example of non-autonomous protein assembly in higher plants and may pose problems for the genetic engineering of RuBisCO from these organisms.

Cancer in children of parents exposed to hydrocarbon-related industries and occupations

Recent animal and human studies suggest that prenatal exposure to carcinogens may increase the risk of childhood malignancy. The Texas Childhood Cancer Study (1976-1977) was designed to test the hypothesis that parental exposure to hydrocarbon-related occupations or industries increases this risk. The study subjects, parents of children with and without cancer, were questioned about their job histories. Parents of 296 children with cancer were not exposed to hydrocarbon-related occupations or industries more often than the uncles and aunts of these children, the parents of neighborhood children, or the parents of 283 children without cancer. During the year before birth, odds ratios for fathers of children seen at a hematology clinic with cancer relative to the uncles of these children (0.93), the fathers of neighborhood children (1.33), and the fathers of children seen at the clinic without cancer (0.50) were not statistically significantly different from 1.00 (p greater than 0.05). This lack of association persisted for the year after birth, the year before diagnosis, and the interval from the year before birth to the year of diagnosis; for different diagnoses; for different ages at diagnosis; and for the industries and occupations of female as well as male parents.