A cell type-specific enhancer drives expression of the chick muscle acetylcholine receptor alpha-subunit gene

The regulation of acetylcholine receptor alpha-subunit gene expression was analyzed by transient expression assays. Using rabbit beta-globin cDNA as a reporter gene, we have confirmed that the 5'-flanking sequence of the chicken acetylcholine receptor alpha-subunit gene directs specific expression in differentiated C2C12 cells, a mouse muscle cell line, but not in undifferentiated C2C12 cells and mouse 3T3 fibroblasts. Testing chimeric plasmids containing Bal31 deletion mutants of the alpha-subunit gene upstream sequence, we found the -116 to -81 region of the alpha-subunit to be responsible for tissue- and stage-specific expression. This 36 bp fragment stimulates the activity of both alpha-subunit and SV40 promoters in a distance- and orientation-independent manner, thus fulfilling the criteria of an enhancer.

Isolation, structure and expression of cDNA and genomic clones for murine eosinophil differentiation factor. Comparison with other eosinophilopoietic lymphokines and identity with interleukin-5

Eosinophil differentiation factor (EDF) is a recently described regulator affecting eosinophil growth and activation. cDNA clones for murine EDF were isolated by direct expression from libraries prepared from the T cell hybrid NIMP-TH1. The longest cDNA clone obtained was 1534 bp in length encoding a polypeptide of 133 amino acids. Two variant cDNAs suggesting alternative RNA processing events were detected. The EDF gene was cloned from a genomic lambda library and a region of 6727 bp encompassing the gene was sequenced. The gene contains three introns 829, 1875 and 79 bases in length and has numerous repetitive sequences. A common, possible regulatory element, including a conserved decamer, lies adjacent to the TATA boxes of the EDF and granulocyte-macrophage colony-stimulating factor (GM-CSF) genes and similar sequences are present in some other lymphokine genes. Recombinant EDF produced in monkey COS cells strongly stimulated the eosinophil lineage and also showed B-cell-growth factor II (BCGFII) activity whereas recombinant murine interleukin-3 and GM-CSF showed much broader activity towards the different myeloid lineages, were less active on eosinophils and had no BCGFII activity. The BCGFII activity of recombinant EDF together with a comparison of the BCGFII (interleukin-5) cDNA sequence with that of the EDF cDNA establishes that these two activities are the properties of a single polypeptide.

Enhanced vasopressin (V2-receptor)-induced sodium retention in mineralocorticoid hypertension

The deoxycorticosterone acetate (DOCA)-Na model of hypertension requires the presence of vasopressin for expression of high blood pressure. In the present study, the effects of vasopressin V2-receptor stimulation were examined in kidneys from rats receiving 1 wk of DOCA-Na or control (olive oil-tap water) treatment. The dose response to vasopressin (10(-10) to 10(-6) M) was tested in microdissected cortical collecting tubule (CCT) segments and adenosine 3',5'-cyclic monophosphate (cAMP) accumulation was significantly increased in segments from DOCA-Na rats vs. controls, confirming our previous study. In other experiments, kidneys from DOCA-Na and control rats were perfused with a modified Krebs-Henseleit buffer (37 degrees C, pH 7.4) and treated with either vehicle or 0.21-2.1 pM 1-desamino-8-D-arginine vasopressin (DDAVP). DDAVP caused significant (P less than 0.05) dose-related reductions in urine excretion (UV) and urinary sodium excretion (UNaV) in both DOCA-Na and control kidneys in the absence of changes in renal hemodynamics. However, DDAVP produced earlier and significantly greater reductions in UV and UNaV in kidneys from DOCA-Na vs. control rats. Percent fractional excretion of sodium was reduced significantly only in the DOCA-Na group (2.1 pM DDAVP). A small degree of antikaluresis was seen with DDAVP in both groups. Thus, DOCA-Na treatment augmented cAMP accumulation in the CCT, accompanied by a significant enhancement of DDAVP-stimulated urinary sodium and water reabsorption at the level of the intact kidney.(ABSTRACT TRUNCATED AT 250 WORDS)

Demonstration of rat preprotachykinin A mRNA in the rat trigeminal ganglion by in situ hybridization histochemistry

The localization of gamma-preprotachykinin A mRNAs in the rat trigeminal ganglion was demonstrated by in situ hybridization histochemistry using the 32P and 35S labelled gamma-preprotachykinin A complementary DNA. In situ hybridization using 32P allowed shorter exposure times, whereas higher resolution of the hybridization signal on both film and emulsion autoradiograms was obtained using 35S. Preprotachykinin A mRNA detected by the gamma-preprotachykinin A probe was localized in about 15 per cent of the trigeminal ganglion cells, most of which were small or medium sized. Immunohistochemical studies using anti-substance P antibodies demonstrated that 15-20 per cent of total trigeminal ganglion cells were positive. These cells were small or medium sized. The result of immunohistochemistry coincided well with that of in situ hybridization histochemistry. The present study showed that the cellular localization of preprotachykinin A mRNA could be analysed by in situ hybridization histochemistry.

Some rules for predicting the base-sequence dependence of DNA conformation

Two tables have been constructed showing the crystal and solution conformations of short sequences of DNA. Each of these DNAs has been found to be in one of three different conformations--the A, B, or Z form--depending upon the base sequence and the environmental conditions. A set of rules is presented showing the tendency of certain base pairs to direct the DNA conformation into the A, B, or Z genus in saturated salt solutions and in crystals. These rules are based on a consideration of nearest-neighbor interactions that are interpreted in terms of 10 different two-letter code words made from the letters denoting the bases guanine (G), cytosine (C), adenine (A), and thymine (T). One table discusses the effect on DNA conformation of 3 strong words that tend to direct a DNA oligomer into either the A, B, or Z genus in crystals or in aqueous solutions containing a high salt concentration (6 M). The second table discusses the remaining 7 code words that appear to have a much weaker effect on conformation. The sequences that are most likely to lead to A-Z, B-Z, and A-B junctions are discussed, as is the possible biological significance of these rules.

Deoxycytidylate hydroxymethylase gene of bacteriophage T4. Nucleotide sequence determination and over-expression of the gene

We describe two approaches to cloning and over-expressing gene 42 of bacteriophage T4, which encodes the early enzyme deoxycytidylate hydroxymethylase. In Bochum a library of sonicated fragments of wild-type phage DNA cloned into M13mp18 was screened with clones known to contain parts of gene 42. Two overlapping fragments, each of which contained one end of the gene, were cleaved at a HincII site and joined, to give a fragment containing the entire gene. In Corvallis a 1.8-kb fragment of cytosine-substituted DNA, believed to contain the entire gene, was cloned into pUC18 and shown to express the enzyme at low level. The cloned fragment bore an amber mutation in gene 42. From the DNA sequence of gene 42, the cloned gene was converted to the wild-type allele by site-directed mutagenesis. Both gene-42-containing fragments were cloned into the pT7 expression system and found to be substantially overexpressed. dCMP hydroxymethylase purified from one of the over-expressing strains had a turnover number similar to that of the enzyme isolated earlier from infected cells. In addition, the N-terminal 20 amino acid residues matched precisely the sequence predicted from the gene sequence. The amino acid sequence of gp42 bears considerable homology with that of thymidylate synthase of either host or T4 origin. The gene 42 nucleotide sequences of bacteriophages T2 and T6 were determined and found to code for amino acid sequences nearly identical to that of T4 gp42.

Fused cells of frog proximal tubule: II. Voltage-dependent intracellular pH

Experiments were performed in intact proximal tubules of the doubly perfused kidney and in fused proximal tubule cells of Rana esculenta to evaluate the dependence of intracellular pH (pHi) on cell membrane potential applying pH-sensitive and conventional microelectrodes. In proximal tubules an increase of the K+ concentration in the peritubular perfusate from 3 to 15 mmol/liter decreased the peritubular cell membrane potential from -55 +/- 2 to -38 +/- 1 mV paralleled by an increase of pHi from 7.54 +/- 0.02 to 7.66 +/- 0.02. The stilbene derivative DIDS hyperpolarized the cell membrane potential from -57 +/- 2 to -71 +/- 4 mV and led to a significant increase of the K+-induced cell membrane depolarization, but prevented the K+-induced intracellular alkalinization. Fused proximal tubule cells were impaled by three microelectrodes simultaneously and cell voltage was clamped stepwise while pHi changes were monitored. Cell membrane hyperpolarization acidified the cell cytoplasm in a linear relationship. This voltage-induced intracellular acidification was reduced to about one-third when HCO-3 ions were omitted from the extracellular medium. We conclude that in proximal tubule cells pHi depends on cell voltage due to the rheogenicity of the HCO-3 transport system.

[Multifactorial analysis of survival in breast cancer]

Eleven clinical and pathological factors were eligible for study in relation to the survival of 617 female patients with breast cancer treated by radical mastectomy. All the patients have been followed for more than five years. The data were analyzed by the Cox's proportional hazards regression model. A final set of five independent significant prognostic factors was obtained. In order of importance, they were clinical stage, age at diagnosis, axillary lymph node status, histologic type and size of the primary. To test the time-dependency of these factors using Cox's model, all except age reduced their prognostic impact significantly after five years, however, age was a powerful prognostic factor for long-term survival. A prognostic index based on the regression coefficients was constructed. This index can give a better prediction for our patients' survival and be taken as reference when formulating treatment protocols for breast cancer.

ACR-NEMA digital imaging and communications standards: minimum requirements

The purposes, implications, and history of development of the American College of Radiology-National Electrical Manufacturers Association (ACR-NEMA) Digital Imaging and Communication Standard and its contents are briefly described, and the minimum requirements of the ACR-NEMA Digital Imaging and Communication Standard are described with a concise introduction of each layer. The usefulness, validity, current status, and future development of the standard are also discussed.

The effects of acetaldophosphamide, a novel stable aldophosphamide analogue, on normal human and leukemic progenitor cells in vitro: implications for use in bone marrow purging

Acetaldophosphamide (A-ALD), a novel in vitro active and stable derivative of aldophosphamide, kills human bone marrow-derived granulocyte-macrophage colony-forming cells (GM-CFC) independent of the cell cycle. The surviving fraction of GM-CFC is an exponential function of the drug concentration and time of exposure. Variation of marrow light-density cell concentration between 2 x 10(6) and 10 x 10(6)/ml does not significantly influence its GM-CFC toxicity. Marrow depleted of GM-CFC by A-ALD subsequently generates GM-CFC when grown in suspension cultures. During the early period after treatment with A-ALD the number of surviving GM-CFC (size of surviving GM-CFC compartment) does influence the speed of the GM-CFC repopulation in suspension cultures. The importance of the number of surviving GM-CFCs for the growth and maintenance of GM-CFC population in such suspension cultures diminishes with time. No significant differences are observed after 2 wk, indicating that the ancestor stem cell population and its regenerative potential responsible for in vitro hematopoiesis have not been significantly affected by the drug treatment. A-ALD-treated progenitor cells retain their ability to integrate with the previously established marrow stromal cell layer and generate GM-CFC within this layer to an extent comparable to that of untreated marrow cells. The effect of A-ALD on human hematopoiesis is comparable to that of 4-hydroperoxycyclophosphamide. Its advantage over 4-hydroperoxycyclophosphamide is a greater stability in vitro. It has sparing effect on GM-CFC ancestor cells. Its toxicity to myeloid leukemia cell line (KBM-3)-derived clonogeneic cells is higher than to the GM-CFC. It is similar in doxorubicin-sensitive (KBM-3) and -resistant (KBM-3/DOX) leukemic cells. Thus, A-ALD appears to be a promising drug for in vitro purging of bone marrow cells.

Clinical report on 62 cases of acute dimethyl sulfate intoxication

Sixty-two cases of accidental acute intoxication from the inhalation of dimethyl sulfate (DMS) are reported. To facilitate clinical evaluation and treatment, as well as identification of capacity for physical labor, a grading system was established according to the history of exposure to DMS, symptoms and signs of respiratory mucosal irritation, findings on chest radiographs, and abnormalities of leukocyte count. Emergency treatment included prophylactic use of glucocorticoids, supplemental oxygen, sedatives, and antibiotics for prevention and treatment of laryngeal and pulmonary edema, pulmonary infections, and other complications. Follow-up studies for 2-12 years have found only mild to moderate impairment in ventilatory capacity in eight cases, with no abnormal findings in ECG, chest films, and routine blood tests. Nearly all patients have resumed their usual work.

Microwave-induced thermoelastic pressure wave propagation in the cat brain

This paper presents direct measurements of acoustic pressure wave propagation in cat brains irradiated with pulsed 2.45-GHz microwaves. Short rectangular microwave pulses (2 microseconds, 15 kW peak power) were applied singly through a direct-contact applicator located at the occipital pole of a cat's head. Acoustic pressure waves were detected by using a small hydrophone transducer, which was inserted stereotaxically into the brain of an anesthetized animal through a matrix of holes drilled on the skull. The measurements clearly indicate that pulsed microwaves induce acoustic pressure waves which propagate with an acoustic wave velocity of 1523 m/s.