Murine retroviral restriction genes Fv-4 and Akvr-1 are alleles of a single locus.

The two murine retroviral restriction genes, Fv-4 and Akvr-1, are very similar in their effects, distributions, ranges of action, and phenotypes. Akvr-1 has been shown to segregate independently in backcrosses with a variety of retroviral restriction loci, including Fv-1, Fv-2, Ril-1, and Ril-2. An allelism test cross of FRG (Fv-4R) X LCRR (Akvr-1R) hybrids mated to AKR mice failed to produce any viremic offspring. These results suggested that Akvr-1R and Fv-4R are alleles of a single locus, Fv-4, on mouse chromosome 12.     

The cloned butyrylcholinesterase (BCHE) gene maps to a single chromosome site, 3q26.

Human tissues have two distinct cholinesterase activities: acetylcholinesterase and butyrylcholinesterase. Acetylcholinesterase functions in the transmission of nerve impulses, whereas the physiological function of butyryl-cholinesterase remains unknown. An atypical form of butyrylcholinesterase or the absence of its activity leads to prolonged apnea following administration of the muscle relaxant suxamethonium. Inheritance of these butyrylcholinesterase variants is consistent with the enzyme activity being encoded in a single autosomal locus, BCHE (formerly CHE1 and E1), which has been assigned to chromosome 3. Previous in situ hybridization of a BCHE cDNA probe gave evidence of homologous sequences at 3q26 and 16q11-q23, raising the possibility of more than one locus coding for butyrylcholinesterase [H. Soreq, R. Zamir, D. Zevin-Sonkin, and H. Zakut (1987) Hum. Genet. 77: 325-328]. Using a different cDNA probe hybridized in situ to 46,XX,inv(3)(p25q21) metaphase chromosomes, we report here the localization of BCHE to a single autosomal location: 3q26.     

Respiratory and psychiatric abnormalities in chronic symptomatic hyperventilation.

Many physicians believe that the hyperventilation syndrome is invariably associated with anxiety or undiagnosed organic disease such as asthma and pulmonary embolus, or both. Twenty one patients referred by specialist physicians with unexplained somatic symptoms and unequivocal chronic hypocapnia (resting end tidal Pco2 less than or equal to 4 kPa (30 mm Hg) on repeated occasions during prolonged measurement) were investigated. All but one complained of inability to take a satisfying breath. Standard lung function test results and chest radiographs were normal in all patients, but histamine challenge showed bronchial hyper-reactivity in two of 20 patients tested, and skin tests to common allergens were positive in three of 18. Ventilation-perfusion scanning was abnormal in a further three of 15 patients studied, with unmatched perfusion defects in two and isolated ventilation defects in one. None of the 21 had thyrotoxicosis, severe coronary heart disease, or other relevant cardiovascular abnormalities. Ten of the 21 patients were neurotic and suffered from chronic psychiatric disturbance characterised by anxiety, panic, and phobic symptoms. The remainder had no detectable psychiatric disorders but reported proportionately more somatic than anxiety symptoms. Severe hyperventilation can occur in the absence of formal psychiatric or detectable respiratory or other organic abnormalities. Asthma and pulmonary embolus must be specifically excluded.     

Results of case-control study of leukaemia and lymphoma among young people near Sellafield nuclear plant in West Cumbria.

OBJECTIVE--To examine whether the observed excess of childhood leukaemia and lymphoma near the Sellafield nuclear plant is associated with established risk factors or with factors related to the plant. DESIGN--A case-control study. SETTING--West Cumbria health district. SUBJECTS--52 Cases of leukaemia, 22 of non-Hodgkin''s lymphoma, and 23 of Hodgkin''s disease occurring in people born in the area and diagnosed there in 1950-85 under the age of 25 and 1001 controls matched for sex and date of birth taken from the same birth registers as the cases. MAIN OUTCOME MEASURES--Antenatal abdominal x ray examinations, viral infections, habit factors, proximity to and employment characteristics of parents at Sellafield. RESULTS--Expected associations with prenatal exposure to x rays were found, but little information was available on viral illnesses. Relative risks for leukaemia and non-Hodgkin''s lymphoma were higher in children born near Sellafield and in children of fathers employed at the plant, particularly those with high radiation dose recordings before their child''s conception. For example, the relative risks compared with area controls were 0.17 (95% confidence interval 0.05 to 0.53) for being born further than 5 km from Sellafield 2.44 (1.04 to 5.71) for children of fathers employed at Sellafield at their conception, and 6.42 (1.57 to 26.3) for children of fathers receiving a total preconceptual ionising radiation dose of 100 mSv or more. Other factors, including exposure to x rays, maternal age, employment elsewhere, eating seafood, and playing on the beach did not explain these relationships. Focusing on Seascale, where the excess incidence has predominantly been reported, showed for the four out of five cases of leukaemia and one case of non-Hodgkin''s lymphoma whose fathers were employed at Sellafield and for whom dose information was obtained that the fathers of each case had higher radiation doses before their child''s conception than all their matched control fathers; the father of the other Seascale case (non-Hodgkin''s lymphoma) was not employed at the plant. These results seem to explain statistically the geographical association. For Hodgkin''s disease neither geographical nor employment associations with Sellafield were found. CONCLUSIONS--The raised incidence of leukaemia, particularly, and non-Hodgkin''s lymphoma among children near Sellafield was associated with paternal employment and recorded external dose of whole body penetrating radiation during work at the plant before conception. The association can explain statistically the observed geographical excess. This result suggests an effect of ionising radiation on fathers that may be leukaemogenic in their offspring, though other, less likely, explanations are possible. There are important potential implications for radiobiology and for protection of radiation workers and their children.     

Ultrastructural histochemistry of the surface lamina of normal articular cartilage

Summary Two collagen-poor, ultramicroscopic layers are described at the surface of canine articular cartilage. They are distinguished by staining with an electron-dense cationic dye, Cupromeronic Blue, in a critical electrolyte concentration technique and by digestion with testicular hyaluronidase. The superficial layer, approximately 50 nm thick, stained at low electrolyte concentrations but failed to stain in conditions specific for sulphated glycosaminoglycans. It was hyaluronidase-resistant and may be either glycoprotein or protein in nature. The deeper layer, 100–400 nm thick, stained positively at electrolyte concentrations specific for sulphated glycosaminoglycans but not in conditions specific for keratan sulphate. It was removed by hyaluronidase digestion. This layer probably represents a chondroitin sulphate-rich proteoglycan.These surface layers may be important in the lubrication of the articular surface and in the permeability and compression resistance of the superficial cartilage zone.