Hormonal regulation of a chicken oviduct messenger ribonucleic acid that shares a common domain with gizzard myosin light chain kinase

Changes in myosin light chain kinase (MLCK) and calmodulin (CaM) mRNAs have been evaluated during estrogen-mediated differentiation of the chicken oviduct. Also examined were acute changes that occur in oviduct RNA from animals stimulated with estrogen, withdrawn from hormone and then injected for 1, 2, and 4 days with synthetic estrogen [diethylstilbestrol (DES)], progesterone (P), or testosterone (T). Small changes were noted in both CaM and MLCK RNAs during primary stimulation when oviduct cells are actively dividing. On the other hand no significant changes were observed during secondary stimulation regardless of the steroid hormone injected. These data support the contention that CaM and MLCK are constitutively expressed but vary as a function of cell cycle. The MLCK mRNA is 5.5 kilobases (kb) but the MLCK cDNA also hybridizes to an oviduct RNA 2.7 kb long. This RNA species is acutely regulated by estrogen, P, and T but in a manner different from that of ovalbumin mRNA. The magnitude of stimulation of the 2.7 kb mRNA by diethylstilbestrol and T is greater than that of ovalbumin whereas changes in response to P are similar. The 12- to 16-fold increase of the 2.7 kb mRNA in response to T is the largest effect reported for this hormone acting on oviduct. The 2.7 kb mRNA encodes an unknown protein yet contains a 520 nucleotide segment that is highly homologous with the COOH-terminal coding portion of the MLCK mRNA. Since this homology does not include either catalytic or CaM-binding domains of MLCK, it is unlikely that the 2.7 kb mRNA encodes a CaM-dependent protein kinase.(ABSTRACT TRUNCATED AT 250 WORDS)     

Treatment of Ph+ chronic myeloid leukemia by gamma interferon

The clinical, hematologic and cytogenetic effects of human recombinant gamma interferon (IFN) were investigated in 14 patients with Ph+ chronic myeloid leukemia (CML). Gamma-IFN was given at a daily dosage of 0.50 mg (= 10 x 10(6) U)/m2 from the 3rd week of treatment on, but the dosage had to be reduced to 0.25 mg/m2 in 10 cases and to 0.35 mg/m2 in 2 cases, because of the severity and persistence of side effects (mainly fever, fatigue, headache and pain). Only 2 patients tolerated the full dosage. The overall response rate was 64% (1 complete and 8 partial hematologic responses). Only patients in stable chronic phase responded. Two out of two patients in unstable chronic phase and two out of two patients in accelerated phase failed to respond. Eight out of nine responding patients remained in remission throughout the duration of treatment (30 to 35 weeks). No karyotypic conversion was detected. These data show that gamma IFN alone is effective in Ph+ CML, but that side effects can limit substantially the dosage and duration of treatment.     

Segregation analysis of 1885 DMD families: significant departure from the expected proportion of sporadic cases

Summary The proportion of sporadic cases of Duchenne muscular dystrophy has been estimated by classical segregation analysis in a pooled sample of 1885 sibships from 7 different countries. A significant departure from the theoretical expectations based on mutation-selection equilibrium is observed (segregation frequency = 0.439 ± 0.017; frequency of sporadic cases = 0.229 ± 0.026, at the maximum likelihood). The occurrence of germinal mosaicism in some of the mothers of Duchenne cases may account for this peculiar finding, although a possible role of inequality of mutation rates in the two sexes cannot be ruled out.     

Studies on the role of amino acids 38-45 in the expression of a functional thyrotropin receptor.

We previously reported that deletion or substitution of a unique eight-amino acid tract (residues 38-45) in the extracellular domain of the human TSH receptor led to the loss of specific ligand binding to the surface of transfected cells. In the present study we analyzed this region in more detail. Using site-directed mutagenesis of the TSH receptor cDNA, we substituted amino acid residues 38-45, either in three overlapping groups of four amino acids each or individually. The resultant TSH receptor mutant cDNAs were stably transfected into Chinese hamster ovary cells, and the cells were tested for their TSH-binding ability. Our data demonstrate that amino acid residues 38-40 and 42-45 in this region of the human TSH receptor can be substituted without alteration in receptor function and are, therefore, not critical in forming or maintaining the TSH-binding site. However, substitution of Cys41, either alone or together with adjacent amino acids, leads to the loss of TSH binding to its receptor. These data suggest a central role for the amino acid in position 41 in preserving the biological function of the TSH receptor.     

Genetical and biochemical comparisons of alcohol dehydrogenase isozymes from Anastrepha fraterculus and A. obliqua (Diptera: Tephritidae): Evidence for gene duplication

The electrophoretic patterns of the enzyme alcohol dehydrogenase (ADH) from Anastrepha fraterculus and A. obliqua were studied. Two loci were found to code for the enzyme in A. fraterculus, and three in A. obliqua. In both species, all isozymes were active in third-instar larvae. A cationic isozyme (Adh-1) was active mainly in the visceral fat body of both species. In A. fraterculus, the locus had an anionic polymorphic isozyme (Adh-3) that was detected in the parietal fat body. In addition to these two loci, a third locus for an anionic isozyme (Adh-2), which was active in the digestive tube of larvae, was present in A. obliqua and probably resulted from gene duplication. For both species, multiple forms of the isozymes are formed by binding of an NAD-carbonyl compound, as in Drosophila melanogaster. Both larvae and early pupae of A. obliqua had almost twice the specific ADH activity as A. fraterculus. The ethanol content of the host fruit infested with A. obliqua (red mombim) was also higher than that of the host fruit infested with A. fraterculus (guava).This research was supported by grants from Conselho Nacional de Desenvolvimento Científico e Tecnologico (CNPq-PIG 40.2486/82).     

Effect of gamma radiation on resting B lymphocytes. I. Oxygen-dependent damage to the plasma membrane results in increased permeability and cell enlargement

Although the susceptibility of resting B lymphocytes to radiation-induced interphase death is well known, the mechanism by which this occurs is not understood. In this report, we use three measures of plasma membrane integrity (increase in cell volume, uptake of trypan blue, and release of 51Cr) to assess the effect of radiation on the resting B cell plasma membrane. The delivery of 500 to 1000 rad caused the majority of resting B cells to enlarge slightly, whereas 3000 rad caused virtually all of the cells to approximately double in size within 3 to 4 hr. Measurement of the release of 51Cr from resting B cells revealed a similar relationship between the dose of radiation and the loss of radioactive label. Trypan blue exclusion was also found to diminish as a function of radiation dose. An analysis of a variety of lymphoid cells suggested that sensitivity to the membrane damaging effects of gamma radiation was in the order of resting B cells greater than resting T cells greater than a long-term L3T4+ T cell clone greater than a B cell lymphoma. LPS-induced B cell blasts treated with 3000 rad were equivalent to 1000 rad-treated resting B cells. The effects of the gamma radiation could be ameliorated by excluding oxygen (a diradical molecule that can potentially enhance the generation and propagation of highly reactive free radicals) at the time of irradiation, or by adding the free radical scavenging agent cysteamine. These data are compatible with the hypothesis that gamma radiation results in damage to the plasma membrane of resting lymphocytes via the generation of highly reactive free radical species. This damage is reflected in a rapid increase in plasma membrane permeability and swelling of the cells, and may play a major role in causing interphase death.     

Rapid method for evaluating intra-erythrocyte Na+ activity

The measurements of intracellular "Na+ activity" was performed in 10 ml of heparinized venous blood. First the blood was three times washed in isotonic magnesium chloride solution (114 mmol/l). Thereby the buffy coat was removed. Then the microhematrocrit was taken for packet cell volume determination. After the erythrocytes were lysed by ultrasound. Sodium "Na+ Activity" is measured in the hemolysate by Ion-Selective electrode. With this method all "pipetting" operations are eliminated and for the "Na+ activity" determination was used ion-selective electrode with an indirect measurements, which is less influenced by the matrix. Reference intervals determined for a healthy population were 7.3 +/- 0.6 mmol/l.