[Multilocular thymic cyst].

We describe a case of multilocular thymic cyst with severe acute inflammation. A 23-year-old man was admitted to our hospital with a sudden onset of chest pain and high fever. A computed tomography scan showed multilocular cystic lesion at anterior mediastinum. We resected the tumor with the thymus by median sternotomy. Macroscopically, the mediastinal mass showed thick-walled multiloculated cavities filled with turbid yellow fluid. Histological examination revealed that the tumor was a multilocular thymic cyst which is reported by Suster.

[Tension hemothorax associated with congenital pulmonary arteriovenous fistula].

We describe a case of intrapleural rupture of pulmonary arteriovenous fistula A 37-year-old woman was admitted to our hospital with a sudden onset of right chest pain. A computed tomography scan showed massive pleural effusion and tension hemothorax. Subsequently the patient went into shock. Partial resection of the lung was performed emergently. Pulmonary arteriovenous fistula is often associated with Rendu-Osler-Weber disease (ROW). Because of her brain arteriovenous malformation and family history, we could not exclude the possibility of ROW.

Evaluation of insulin secretion of isolated rat islets cultured in extracellular matrix.

Islet isolation involves enzymatic digestion of the interstitial matrix and mechanical disruption of the tissue. It is possible that a fundamental change of islet biology resulting from the loss of critical factors required for islet function or survival will occur. Extracellular matrix (ECM) is one of the most important components of the islet microenvironment. Reconstruction of the cell-matrix relationship seems to be effective for improving the loss of differentiated islet structure and function. The purpose of this study was to characterize and compare the effects of collagen gel mixture or Matrigel on beta-cell function and islet cell survival. After isolation by the collagenase digestion technique, rat islets were divided and cultured with various types of collagen gel mixture. They were assessed for their glucose-stimulated insulin secretion and cell viability. Glucose-induced insulin secretion of islets cultured with collagen type I gel or a mixture of collagen type I and IV was improved after 11 days in culture. In conclusion, a type of gel composed of collagen type I and/or type IV as an islet microenvironment is sufficient to maintain glucose responsiveness and may be useful for islet transplantation.

Development of a new method to induce angiogenesis at subcutaneous site of streptozotocin-induced diabetic rats for islet transplantation.

The subcutaneous space is a potential site for clinical islet transplantation. Even though there are several advantages, poor blood supply at this site mainly causes failure of islet survival. In this study, angiogenesis was induced in advance at the diabetic rats subcutis for islet transplantation by implanting a polyethylene terephthalate (PET) mesh bag containing gelatin microspheres incorporating basic fibroblast growth factor (bFGF) (MS/bFGF) and a collagen sponge. The bFGF was incorporated into gelatin microspheres for controlled release of bFGF. As controls, a PET mesh bag with or without either collagen sponges or MS/bFGF was implanted at the subcutaneous site of diabetic rats. Macroscopic and microscopic examinations revealed the formation of capillary network in and around the PET mesh bag containing MS/bFGF and collagen sponges 7 days after implantation when compare with other control groups. When tissue hemoglobin level was also measured, a significantly high level of hemoglobin amount was observed compared with that of control groups. When allogeneic islets mixed with 5% agarose were transplanted into the prevascularized rat subcutis, normoglycemia was maintained for more than 40 days, while other control groups were ineffective. This study demonstrated that combination of gelatin microspheres incorporating bFGF and collagen sponges enabled the mesh to induce neovascularization even at the subcutaneous site of streptozotocin-induced diabetic rats, resulting in improved function of islet transplantation.

Isolation, culture, and characterization of endocrine cells from 6-month-old porcine pancreas.

Porcine endocrine cells were isolated from pancreas of 6-month-old pigs by two-step enzymatic digestion procedures. They were separated by the density gradient (isopycnic) centrifugation method using Histopaque-1077. Isolated cells were cultured and divided into two groups: suspension cells and adhesion cells. Suspension cells maintained their cell numbers on and after 7 days in culture. Approximately 1 x 10(7) cells were obtained from single pancreas of a 6-month-old pig. The cultured suspension cells took up dithizone (DTZ) staining 14 days after isolation in culture and indicated the presence of beta-cells. In in vitro study, the suspension cells were capable of secreting insulin into the culture medium. The suspension cells were tested for insulin and glucagon staining by Western blot analysis. These results indicated the maintenance of endocrine cell function after isolation. However, cultured adhesion cells failed to maintain their function during culture. In in vivo study, the suspension cells were transplanted into diabetes-induced nude mice. Reduction in blood glucose level was obtained after transplantation. Intraperitoneal glucose tolerance test (IPGTT) results showed a normal pattern of blood glucose clearance. After 1 week, the transplanted endocrine cells were detected with anti-insulin antibody by immunostaining and it showed the presence of viable beta-cells under the renal capsule of nude mice. Collectively, our results suggest that isolated and cultured suspension porcine endocrine cells maintained their endocrine function. These endocrine cells can be used as isolated islets for further study, including transplantation experiments.

Noise-induced regularity of spatial wave patterns in subalpine abies forests

In subalpine forests dominated by Abies species in Japan and northeastern United States, trees show traveling wave of regeneration with many striped zones of tree dieback, moving downwind at a constant rate. Previous theoretical studies have demonstrated that a very simple model can generate wave-like spatio-temporal patterns of tree regeneration in a lattice-structured habitat with each site occupied by a cohort of trees. A cohort taller than the average height of its windward neighbor experiences stand-level dieback in the next time step and the height becomes zero. Otherwise the cohort increases its height at a constant rate. Starting from a random initial pattern, this simple deterministic model can generate a saw-toothed pattern that moves downwind at a constant rate, but the distance between adjacent dieback zones has a large variance. In this paper, we study the effects of "noises" in tree dieback rules in two forms which help to generate more regular patterns: (1) additional random disturbances at a low rate, which change the size of "clusters" (defined as a group of cohorts between adjacent dieback zones) by splitting a large cluster into two or by merging a small one with a neighbor, and (2) the stochastic rule of tree dieback, represented by the probability of dieback in unit time being a sigmoidal function of the difference in the tree height between the site and the windward neighbors. These noises are effective both for one-dimensional and two-dimensional models, but spatial patterns are much more regular in the two-dimensional model than in the one-dimensional model. Copyright 1998 Academic Press

Three-dimensional brain visualization for metachromatic leukodystrophy.

The basic understanding of many neurogenetic diseases requires study of the clinical, biochemical, and pathological aspects. To study the pathological aspects, the organs affected by the disease must be observed. We have used volume visualization techniques to create three-dimensional (3D) brain images of a patient with late infantile metachromatic leukodystrophy (MLD). The 3D brain images showed clearly, stereographically, and non-invasively the intracerebral lesion. This lesion, which indicated hyperintensity in magnetic resonance (MR) images, extended throughout the periventricular white matter. The 3D brain images are provided to integrate information. Volumetric ray-casting was useful in obtaining directly images of the entire brain and in allowing an intuitive understanding of the extension of the lesion in three dimensions and of the extent of the defects in the MLD brain. Isosurfacing facilitated a clear extraction of the lesion located by volumetric ray-casting. Each technique used in this study played a role in visualization and their use was complementary. 3D brain images will promote morphological investigation of neurogenetic diseases.

Expression of protective protein in human tissue.

The authors investigated by immunohistochemistry the distribution of protective protein in human tissues. Immunoreactivity was observed in the cytoplasm, revealing a granular pattern and cell type specificity. The most intense staining was observed in the large neurons of brain, distal and collecting tubular cells of kidney, epithelial cells of bronchus, and Leydig cells of testis. In a patient with galactosialidosis type IIa, all these stains were absent. The neurons that were most strongly stained in the control group, such as the Betz cells, neurons in the basal forebrain, motor neurons in the cranial nerve nuclei, and ventral horn cells of the spinal cord, were markedly ballooned in the patient with galactosialidosis.

[Clinical and laboratory studies in seven patients with pre-B cell leukemia in children].

We have experienced and treated seven patients of pre-B cell leukemia in childhood. Clinical, cytological and ultrastructural characteristics of them were studied. Most of them had higher counts of white blood cells, hepatosplenomegaly, high value of lactic dehydrogenase and various karyotype abnormalities at onset. The chromosomal translocation t (1; 19) that is supposed to be specific to pre-B cell ALL was found in four of seven of our cases. In the seven patients, survival was studied in comparison to that of 27 common ALL patients at our hospital that are common in childhood acute leukemia. Although no difference in remission duration and survival time between pre-B cell ALL patients and common ALL group, there have been seen the tendency that remission and survival were of shorter duration for patients with pre-B cell ALL.

[Cutaneous malignant lymphoma in childhood].

Two cases of malignant lymphoma in childhood were studied. The first case was a Japanese girl aged 8, in whom the primary site was skin of the right temple. The second case was a 4-year-old Japanese boy, who had metastases to the abdominal skin. Histochemical findings indicated B-cell lineage in both cases. Primary cutaneous lymphoma is extremely rare in childhood. Fourteen such cases that have been reported in Japan and our case added to them, were reviewed. The relationship between their morphologic, immunohistochemical and clinical findings were summarized and discussed. Although the prognosis of lymphoma confined to skin in childhood has been reported not to be bad as compared with other types of lymphoma, our first such case was fatal. This suggests that appropriate initial treatment is very important. Recent advances in science may clarify the clinical and biologic characteristics of this tumor in the near future.

Protective effect of 17beta-estradiol on ischemic acute renal failure through the PI3K/Akt/eNOS pathway.

Estrogens attenuate renal injury induced by ischemia/reperfusion (I/R), an effect that is related to nitric oxide production in the post-ischemic kidney. The compound 17beta-estradiol (E(2)-beta) acting via estrogen receptors (ERs) is known to activate endothelial nitric oxide synthase (eNOS) through the phosphatidylinositol-3 kinase (PI3K)/Akt pathway. We determined if this pathway contributes to the renoprotective effect of E(2)-beta in the uninephrectomized ischemia reperfusion rat model of acute renal injury. Treatment with E(2)-beta suppressed the I/R-induced increases in blood urea nitrogen, plasma creatinine, urine flow, and fractional excretion of sodium while augmenting creatinine clearance, renal blood flow, and urine osmolality, indicating attenuation of renal injury. Phosphorylation of Akt and eNOS protein was significantly increased 30-60 min after reperfusion in estradiol-treated compared to vehicle-treated rats. The protective effects of E(2)-beta and protein phosphorylation were reversed by the PI3K inhibitor wortmannin or the ER antagonist tamoxifen. Furthermore, the E(2)-beta-induced renoprotective effects were not seen in eNOS knockout mice with renal injury. We conclude that the E(2)-beta-induced renoprotective effect is due to activation of the PI3K/Akt pathway followed by increased eNOS phosphorylation in the post-ischemic kidney.

Pollen coupling of forest trees: forming synchronized and periodic reproduction out of chaos.

Many of the tree species in mature forests show masting; their reproductive activity has a large variance between years and is often synchronized between different individuals. In this paper, we analyse a globally coupled map model in which trees accumulate photosynthate every year, produce flowers when the energy reserve level exceeds a threshold, and set seeds and fruits at a rate limited by pollen availability. Without pollen limitation, the trees in the forest show independent chaotic fluctuation. Coupling of trees via pollen exchange results in reproduction being synchronized partially or completely over the forest. The whole forest shows diverse dynamical behaviors determined by the values of two essential parameters; the depletion coefficient k and the coupling strength beta. We find perfectly synchronized periodic reproduction, synchronized reproduction with a chaotic time series, clustering phenomena, and chaotic reproduction of trees without synchronization over individuals. There are many parameter windows in which synchronized reproduction of trees shows a stable periodic fluctuation. For perfectly synchronized forests, we can calculate all the Lyapunov exponents analytically. They show that synchronized reproduction of all the trees in the forest can only occur when trees flower at low (but positive) levels in a significant fraction of years, resulting in small fruit sets due to outcrossed pollen limitation. This is consistent with the observation that the distinction between mast years and non-mast years is often not clear cut.

Variable timing of reproduction in unpredictable environments: adaption of flood plain plants.

We study the evolutionarily stable reproductive timing of annual plants that face unpredictable environmental disturbances. Plants living in a riverbed often experience a disturbance before they reproduce, suffering major fitness loss. Plants reproducing prior to the flood season are free from the risk of lost reproduction, but a small flowering plant can produce only a few numbers of seeds. If the date of disturbance is unpredictable, a mixed strategy of reproductive timing may evolve in which individuals of the same genotype have different reproductive dates. We calculate the evolutionarily stable phenotype distribution analytically. Depending on parameters, the ESS distribution is either (1) a timid strategy-the plant reproduces when small, prior to the major disturbance season; (2) a bold strategy-the plant reproduces only when it is fully grown; (3) a mixture of early and late reproduction; or (4) dates of reproduction spread over a wide interval. We also examine the effects of developmental and environmental noises that make realized flowering dates deviate from that programmed by the genotype, which follows the ESS distribution. In the presence of noise, the ESS distribution of programmed timing of reproduction is discrete.

Synthesis of bipyridylene-bridged bisporphyrin by nickel-mediated coupling reaction: ON-OFF control of cofacial porphyrin unit by reversible complexation.

Novel bipyridylene-bridged bisporphyrin 1a, in which two porphyrin units were attached directly to symmetrical 4,4'-positions of the 2,2'-bipyridyl group, was synthesized by a nickel(0)-mediated homocoupling reaction of 5,10,15-tris(n-heptyl)-20-(2'-bromo-4'-pyridyl)porphyrinatozinc (3a) in 58% yield. Spatial geometries of two porphyrins in 1a were regulated by reversible complexation of the bipyridyl part with PdCl(2). Thus, the addition of 2.2 equiv of palladium chloride to 1a converted the freely rotating conformation to the cofacial bisporphyrin 2a. The subsequent addition of 4,4'-dimethyl-2,2'-bipyridine 9 regenerated the initial bisporphyrin 1a.

Production of monoclonal antibody and development of enzyme-linked immunosorbent assay for kanamycin in biological matrices.

Monoclonal antibodies (MAbs) against kanamycin were prepared by using a kanamycin-bovine gamma-globulin conjugate for the immunization of mice. Splenocytes from BALB/c immunized mice were fused with P3X63Ag8U.1 myeloma cells. This resulted in two hybridoma cell lines. Fifty per cent inhibition concentrations (IC50) for the MAbs were 2 and 5 ng ml-1. One MAb (IC50 = 2 ng ml-1) was named #22 and was used to develop quantitative assays for kanamycin by means of an enzyme-linked immunosorbent assay (ELISA). The detection limit was 0.2 ng ml-1 and the standard deviations were 0.2-4.4% for intra-assay and 0.6-4.7% for inter-assay, respectively. The detection limits using peroxidase were 4 ppb in cattle milk, cattle plasma, cattle urine, swine plasma, swine urine and chicken plasma. Using the MAb #22 produced, a rapid test kit based on an immunochromatographic method was developed. The detection limits using the kit were 50 ppb in cattle milk, cattle plasma, cattle urine and chicken plasma.

Artificial ion channels showing rectified current behavior.

Voltage-dependent artificial ion channels 3 and 4 were synthesized. Two cholic acid derivatives were connected through a m-xylylene dicarbamate unit at 3-hydroxyl groups. Asymmetries were introduced by terminal hydrophilic groups, carboxylic acid and phosphoric acid for 3 and hydroxyl and carboxylic acid for 4. Under basic conditions, these headgroups in 3 and 4 are expected to be dissociate into -1/-2 (pH 8.2) and 0/-1 (pH 7.2), respectively. Single ion channel properties were examined by a planar bilayer lipid membrane method under symmetrical 500 mM KCl at pH 8.2 or 7.2. When 3 and 4 were introduced into the bilayer membrane under application of positive voltage (a positive-shift method), the current values at positive applied voltage were larger than the corresponding ones at the negative applied voltage. The current-voltage plots were fitted by curves through a zero point to show clear rectification properties. The direction of rectification could be controlled by positive- or negative-shift methods. Vectorial alignment of terminal headgroup charges by the voltage-shift incorporation is essential for giving voltage-dependent rectified ion channels.