Loss of secretory response of rat basophilic leukemia (2H3) cells at 40 degrees C is associated with reversible suppression of inositol phospholipid breakdown and calcium signals

Antigen-induced stimulatory signals as well as histamine secretion from the RBL-2H3 cells were found to be highly temperature dependent. There was no hydrolysis of inositol phospholipids, increase in cytosol calcium concentration (calcium signal), or secretion upon antigen stimulation at temperatures below 20 degrees C. At higher temperatures (i.e., 20 to 37 degrees C), all responses increased in extent with increase in temperature. Temperatures of 38 degrees C or higher, however, resulted in a marked decline in all responses, until no responses were observed at 40 to 42 degrees C. As indicated by the decay in calcium signal, the duration of response was also temperature dependent. The response was of long duration at 30 to 32 degrees C, but it became progressively more transient as the temperature was increased from 32 to 40 degrees C. The effects of low or high temperature were fully reversible. For example, in the presence of antigen, stimulatory signals immediately appeared once the temperature was decreased from 40 to 37 degrees C. Although the diminished responses could be explained, in part, by a reduction in rates of IgE receptor aggregation and phospholipase C activity, the reductions were insufficient to account for complete loss of activity at 40 degrees C. We conclude that generation of intracellular signals in 2H3 cells is blocked by quite small elevations in temperature above 37 degrees C, possibly as consequence of changes in membrane fluidity.     

Suppressive effect of elcatonin, an eel calcitonin analogue, on excessive urinary hydroxyproline excretion in polyostotic fibrous dysplasia (McCune-Albright's syndrome)

A 12-year-old Japanese girl with polyostotic fibrous dysplasia and endocrine concomitants, was treated with elcatonin, a synthetic eel calcitonin analogue, 10 MRC unit/twice a week given by intramuscular injection. Significant decreases in 24 hr urinary content of hydroxyproline and other amino acids from bone collagen were observed during the course of treatment over 5 months. This biochemical result suggests that the synthetic eel calcitonin analogue exhibits the therapeutic effect in patients with polyostotic fibrous dysplasia by inhibiting bone resorption.     

Purification and characterization of myosin light-chain kinase from porcine myometrium and its phosphorylation and modulation by cyclic AMP-dependent protein kinase

Myosin light-chain kinase was purified from porcine myometrium to apparent homogeneity at about 262-fold with an Mr of 130 000 as determined by SDS-polyacrylamide gel electrophoresis and a sedimentation coefficient of 4.5 S. The approximate content of the soluble myosin light-chain kinase was estimated to be about 0.85 microM. The purified enzyme exhibited strict substrate specificity only for 20-kDa myosin light chain and Ka values of 0.6 nM and 0.3 microM for calmodulin and Ca2+, respectively. The enzyme was phosphorylated by the catalytic subunit of cyclic AMP-dependent protein kinase, which resulted in a decrease in the affinity for calmodulin of 4-7-fold without effect on the Vmax. The maximal amount of phosphate incorporated into the enzyme was 0.5-0.8 and 1.0-1.4 mol per mol of the enzyme in the presence and absence of Ca2+ and calmodulin, respectively. In the presence of a subsaturating concentration of calmodulin, the enzyme showed a lower sensitivity for Ca2+ by phosphorylation.     

Effect of alpha-fluoromethylhistidine on the histamine content of the brain of W/Wv mice devoid of mast cells: turnover of brain histamine

In the brains of W/Wv mutant mice that have no mast cells, the histidine decarboxylase (HDC) level is as high as in the brain of congenic normal mice (+/+), but the histamine content is 53% of that of +/+ mice. The effects of alpha-fluoromethylhistidine (alpha-FMH) on the HDC activity and histamine content of the brain of W/Wv and +/+ mice were examined. In both strains, 30 min after i.p. injection of alpha-FMH the HDC activity of the brain had decreased to 10% of that in untreated mice. The histamine content decreased more gradually, and after 6 h about half of the control level remained in +/+ mice, whereas histamine had disappeared almost completely in W/Wv mice. It is concluded that the portion of the histamine content that was depleted by HDC inhibitor in a short time is derived from non-mast cells, probably neural cells. The half-life of histamine in the brain of W/Wv mice was estimated from the time-dependent decrease in the histamine content of the brain after administration of alpha-FMH: 48 min in the forebrain, 103 min in the midbrain, and 66 min in the hindbrain.     

Serologic dissection of HLA-D specificities by the use of monoclonal antibodies

To study the gene products of the HLA complex, we produced two monoclonal antibodies, termed HU-18 and HU-23. They were active in complement-dependent cytotoxicity and detected B-cell alloantigens encoded by a locus (or loci) linked to HLA. When three types of HLA-DR4 homozygous B-cell lines with different HLA-D specificities were tested for reactivity with HU-18 and HU-23, they displayed distinct reaction patterns depending on the HLA-D specificities they possessed: EBV-Wa (HLA-DYT homozygous), negative for both HU-18 and HU-23; KT2 and KOB (HLA-DKT2 homozygous), positive only for HU-18; and ER (HLA-Dw4 homozygous), positive for both. These differential reaction patterns were further confirmed by testing against a panel of 17 HLA-DR4-positive peripheral blood lymphocytes with known HLA-D specificities. Thus, these monoclonal antibodies allow us to identify HLA-DYT, HLA-DKT2, and HLA-Dw4 solely by serologic methods. This is the first clearcut serologic identification of these three HLA-DR4-associated HLA-D specificities, which have been indistinguishable by conventional serology and identified only by cellular techniques. It is hoped that immunochemical investigations using HU-18 and HU-23 will advance our understanding of the HLA-D region on a molecular level.     

Three-Dimensional Labeling Program for Elucidation of the Geometric Properties of Biological Particles in Three-Dimensional Space

For all biological particles such as cells or cellular organelles, there are three-dimensional coordinates representing the centroid or center of gravity. These coordinates and other numerical parameters such as volume, fluorescence intensity, surface area, and shape are referred to in this paper as geometric properties, which may provide critical information for the clarification ofin situmechanisms of molecular and cellular functions in living organisms. We have established a method for the elucidation of these properties, designated the three-dimensional labeling program (3DLP). Algorithms of 3DLP are so simple that this method can be carried out through the use of software combinations in image analysis on a personal computer. To evaluate 3DLP, it was applied to a 32-cell-stage sea urchin embryo, double stained with FITC for cellular protein of blastomeres and propidium iodide for nuclear DNA. A stack of optical serial section images was obtained by confocal laser scanning microscopy. The method was found effective for determining geometric properties and should prove applicable to the study of many different kinds of biological particles in three-dimensional space.     

Age-dependent aluminum accumulation in the human aorta and cerebral artery

The purpose of this study was to determine the extent of aluminum (Al) accumulation in the human aorta and cerebral arteries. The Al contents in the aortae and in the cerebral arteries from 23 human subjects was determined by inductively coupled plasma atomic emission spectrophotometry (ICP-AES). The subjects' age range was 45–99-yr-old; 15 of the subjects were males and 8 were females. Al was detected in twelve aortae and in six cerebral arteries, when the entire specimen was analyzed. Two specimens where Al was found in the cerebral arteries contained no Al in the aorta. No relationship to the subject's sex was found. When related to age, two groups were established. Group L (45–75 yr old) and group H (>75 yr old), which exhibited aortal Al concentrations of 33.3 and 72.7%, respectively. When the aortic wall was dissected into the tunica intima, media, and adventitia, Al was found mainly in the tunica media. In the aorta, significant relationships were found between Al and phosphorus (P) levels (r=0.801,p<0.01) and between Al and calcium (Ca) (r=0.661,p<0.05). We have concluded that Al accumulation is age-dependent and that it occurs both in the aorta and in the cerebral artery. In the aorta, accumulation occurs mainly in the tunica media. Both P and Ca appear to enhance aortal Al accumulation.     

Urocystis tranzscheliana,a newly recorded smut fungus onPrimula sieboldii from Japan

A smut fungus onPrimula sieboldii was newly found in Japan and identified asUrocystis tranzscheliana by comparative morphology. This species causes systemic infection ofP. sieboldii and produces sori in its ovaries.Contribution No. 121, Laboratories of Plant Pathology and Mycology, Institute of Agriculture and Forestry, University of Tsukuba.     

Stable isotopic structure of aquatic ecosystems

Isotopic, biogeochemical and ecological structure can provide a new dimension for understanding material flows, and the simultaneous function and structure of an ecosystem. Distributions ofδ ¹³C andδ ¹⁵N for biogenic substances in the Nanakita river estuary involving Gamo lagoon in Japan were investigated to construct isotope biogeochemical and ecological structure for assessing fate and transfer of organic matter, and food web structure. The isotopic framework of the ecosystem was successfully described in aδ ¹⁵N–δ ¹³C map. In this estuary the variations of isotope ratios of biogenic substances were clearly explained by the mixing of land-derived organic matter, and marine-derived organic matter. A trophic-level effect of¹⁵N enrichment was clearly observed. Organisms were classified into three groups depending upon the contribution of land-derived organic matter in a food chain. Almost all biota except mollusca in the lagoon depend on organic matter of marine origin. The contributions of both land and marine organic matter were comparable for mollusca in the lagoon.