Mutations in the V2 vasopressin receptor gene are associated with X-linked nephrogenic diabetes insipidus.

X-linked nephrogenic diabetes insipidus (NDI) is a rare disorder in which the kidney is insensitive to the antidiuretic hormone, vasopressin. It has been proposed that the kidney-specific V2 vasopressin receptor, a G protein-coupled receptor, is defective in this disorder as both the disease and the receptor map to Xq28. We report six unique mutations in the V2 receptor gene of five unrelated NDI patients, with one patient having two mutations. The most severely affected patient has a nonsense mutation which would terminate the protein in transmembrane domain III. Other mutations include three missense mutations, a frameshift and one small in-frame deletion. These results represent one of the first examples of recessive mutations affecting a G protein-coupled receptor.     

Human growth hormone in urine: development of an ultrasensitive radiometric assay

An immunoradiometric assay for human growth hormone (HGH) has been developed which has a detection limit of 1 ng/l and can measure HGH in unextracted urine from normal children and adults. The assay is based on a two-step procedure, using a solid-phase goat-anti-HGH immunosorbent for immunoextraction and [125I]-labeled monoclonal HGH-antibody for detection and quantification. The assay is not affected by urea, NaCl or changes of pH from 5-8. The mean urine HGH concentration in normal children is 6.78 +/- 7.6 (SD) pg/ml, in patients with HGH-deficiency 1.3 +/- 0.9 pg/ml which increases to 11.7 +/- 13.4 pg/ml on the day of growth hormone injection.     

Retroviruses released from a human tumor xenograft in nude mice induce colony-stimulating factor (CSF) activity in human fibroblastic cells

Summary A human colony-stimulating factor (CSF)-producing tumor transplanted into athymic nude mice released retroviruses in vitro. The viruses induced CSF activity in human fibroblastic cell lines.     

A method for determining cross-measurements of motor neurons

Summary This new triangulation technique allows the investigator to make cross-measurements of individual cells quickly and easily with a high degree of accuracy and reliability.     

Persistence of body weight cycles in dormice maintained with a limited food supply.

Dormice kept under food restriction for several months continued to exhibit body weight cycles with characteristic periods of about 2 months, despite an impaired ability to attain the high body weight levels observed in ad libitum conditions. These results imply that the cycle is controlled by a mechanism whose properties are more consistent with asn endogenous oscillator than with a sequence of stages, in which the relevant stages are defined by upper and lower body weight limits.