Application of X-ray microcomputed tomography in the characterization of irradiated nuclear fuel and material specimens.

X-ray microcomputed tomography (µCT) was applied in characterizing the internal structures of a number of irradiated materials, including carbon-carbon fibre composites, nuclear-grade graphite and tristructural isotropic-coated fuel particles. Local cracks in carbon-carbon fibre composites associated with their synthesis process were observed with µCT without any destructive sample preparation. Pore analysis of graphite samples was performed quantitatively, and qualitative analysis of pore distribution was accomplished. It was also shown that high-resolution µCT can be used to probe internal layer defects of tristructural isotropic-coated fuel particles to elucidate the resulting high release of radioisotopes. Layer defects of sizes ranging from 1 to 5 µm and up could be isolated by tomography. As an added advantage, µCT could also be used to identify regions with high densities of radioisotopes to determine the proper plane and orientation of particle mounting for further analytical characterization, such as materialographic sectioning followed by optical and electron microscopy. In fully ceramic matrix fuel forms, despite the highly absorbing matrix, characterization of tristructural isotropic-coated particles embedded in a silicon carbide matrix was accomplished using µCT and related advanced image analysis techniques.

Characterization of spontaneous malignant lymphomas in Japanese macaques (Macaca fuscata).

Lymphomas are common spontaneous tumors in nonhuman primates but remain poorly characterized in Japanese macaques (Macaca fuscata). This study examined 5 cases of spontaneous malignant lymphoma in Japanese macaques, focusing on the immunophenotypes and presence of simian lymphocryptoviruses, which are Epstein-Barr virus-related herpesviruses in nonhuman primates. The macaques with lymphoma were 5 to 28 years old, indicating that lymphomas develop over a wide age range. The common macroscopic findings were splenomegaly and enlargement of lymph nodes. Histologic and immunohistochemical analyses revealed that all cases were non-Hodgkin type and exhibited a T-cell phenotype, positive for CD3 but negative for CD20 and CD79α. The lymphomas exhibited diverse cellular morphologies and were subdivided into 3 types according to the World Health Organization classification. These included 3 cases of peripheral T-cell lymphoma, not otherwise specified; 1 case of T-cell prolymphocytic leukemia; and 1 case of an unclassifiable T-cell lymphoma. Positive signals were detected by in situ hybridization in 2 of the 4 examined cases using probes for the Epstein-Barr virus-encoded small RNA (EBER). Furthermore, the presence of M. fuscata lymphocryptovirus 2, a macaque homolog of Epstein-Barr virus, was demonstrated in EBER-positive cases by polymerase chain reaction amplification followed by direct sequencing. Immunohistochemistry using antibody to the Epstein-Barr virus-encoded nuclear antigen 2 was negative, even in the EBER-positive cases. The present study suggests that T-cell lymphoma is more common than B-cell lymphoma in Japanese macaques and that M. fuscata lymphocryptovirus 2 is present in some cases.

Direct observations of energy transfer from resonant electrons to whistler-mode waves in magnetosheath of Earth.

Electromagnetic whistler-mode waves in space plasmas play critical roles in collisionless energy transfer between the electrons and the electromagnetic field. Although resonant interactions have been considered as the likely generation process of the waves, observational identification has been extremely difficult due to the short time scale of resonant electron dynamics. Here we show strong nongyrotropy, which rotate with the wave, of cyclotron resonant electrons as direct evidence for the locally ongoing secular energy transfer from the resonant electrons to the whistler-mode waves using ultra-high temporal resolution data obtained by NASA's Magnetospheric Multiscale (MMS) mission in the magnetosheath. The nongyrotropic electrons carry a resonant current, which is the energy source of the wave as predicted by the nonlinear wave growth theory. This result proves the nonlinear wave growth theory, and furthermore demonstrates that the degree of nongyrotropy, which cannot be predicted even by that nonlinear theory, can be studied by observations.

Collaborative Research Activities of the Arase and Van Allen Probes.

This paper presents the highlights of joint observations of the inner magnetosphere by the Arase spacecraft, the Van Allen Probes spacecraft, and ground-based experiments integrated into spacecraft programs. The concurrent operation of the two missions in 2017-2019 facilitated the separation of the spatial and temporal structures of dynamic phenomena occurring in the inner magnetosphere. Because the orbital inclination angle of Arase is larger than that of Van Allen Probes, Arase collected observations at higher L -shells up to L ∼ 10 . After March 2017, similar variations in plasma and waves were detected by Van Allen Probes and Arase. We describe plasma wave observations at longitudinally separated locations in space and geomagnetically-conjugate locations in space and on the ground. The results of instrument intercalibrations between the two missions are also presented. Arase continued its normal operation after the scientific operation of Van Allen Probes completed in October 2019. The combined Van Allen Probes (2012-2019) and Arase (2017-present) observations will cover a full solar cycle. This will be the first comprehensive long-term observation of the inner magnetosphere and radiation belts.

Direct measurements of two-way wave-particle energy transfer in a collisionless space plasma.

Particle acceleration by plasma waves and spontaneous wave generation are fundamental energy and momentum exchange processes in collisionless plasmas. Such wave-particle interactions occur ubiquitously in space. We present ultrafast measurements in Earth's magnetosphere by the Magnetospheric Multiscale spacecraft that enabled quantitative evaluation of energy transfer in interactions associated with electromagnetic ion cyclotron waves. The observed ion distributions are not symmetric around the magnetic field direction but are in phase with the plasma wave fields. The wave-ion phase relations demonstrate that a cyclotron resonance transferred energy from hot protons to waves, which in turn nonresonantly accelerated cold He+ to energies up to ~2 kilo-electron volts. These observations provide direct quantitative evidence for collisionless energy transfer in plasmas between distinct particle populations via wave-particle interactions.

Spatiotemporal treadmill gait measurements using a laser range scanner: feasibility study of the healthy young adults.

OBJECTIVE: Spatio-temporal parameters are typically used for gait analysis. Although these parameters are measured by sophisticated systems such as 3D motion capture system or optoelectronic bars, these systems cannot be deployed easily because of their high costs, large space requirements and elaborate set-up. The purpose of this study is to develope a system for measuring spatiotemporal gait parameters using a laser range scanner during treadmill gait. APPROACH: To calculate accurate spatiotemporal parameters, the differences between the laser range scanner measured values and the reference values obtained from a 3D motion capture system were investigated in thirty subjects. From measurements in time and position at foot contact/off, adjustments to compensate for the differences in time and position were derived. Then, to determine the validity of the proposed system, values from the proposed system and the reference system were compared in four additional subjects. MAIN RESULTS: The results indicate that the data from the laser range scanner demonstrate certain differences in time and position compared with reference values. However, when compensation values were introduced, each spatiotemporal parameter correlated well with the reference values. SIGNIFICANCE: This newer system is smaller, is easier to deploy and requires less training than the 3D motion capture system.

Disease-specific expression of VEGF and its receptors in AML cells: possible autocrine pathway of VEGF/type1 receptor of VEGF in t(15;17) AML and VEGF/type2 receptor of VEGF in t(8;21) AML.

Various angiogenic factors, such as vascular endothelial growth factor (VEGF) and an associated molecule, placenta growth factor (PlGF), are thought to be important for normal and malignant hematopoiesis. This study examined mRNA expression of VEGF, PlGF and receptors for these molecules in AML cells and identified the disease-specific patterns of expression. AML M3 having t(15;17) abnormality showed highest expression of VEGF and VEGF receptor type 1 (VEGFR1), suggesting the autocrine pathway of VEGF-VEGFR1. Then, t(8;21) AML demonstrated augmented expression of VEGF and VEGF receptor type 2 (VEGFR2), suggesting VEGF-VEGFR2 autocrine pathway. Then, addition of VEGFR2 kinase inhibitor in Kasumi-1, a t(8;21) AML cell line, resulted in marked inhibition of cell growth, although growth inhibitory effect of R2 kinase inhibitor to HL-60 was marginal. In addition, cell cycle analysis study showed S-phase cell population reduction by R2 kinase inhibitor in Kasumi-1, but not in HL-60. This observation is thought to be the rationale for novel molecular target therapy directed to angiogenic molecules.

Transformation and neoplastic development of hamster chondrocytes after exposure to 4-nitroquinoline-1-oxide and 3-methylcholanthrene in tissue culture.

Sternal hyaline cartilages of Syrian hamsters were dissociated with collagenase and culured. Primary monolayer cultures of the dissociated cells were morphologically homogeneous. Secondary cultures of the chondrocytes were treated with 1 x 10(-6) or 2 x 10(-6) M 4-nitroquinoline-1-oxide (4NQO) for 3 hours or with 5 or 10 microgram 3-methylcholanthrene (MCA)/ml for 3 days. Cultured chondrocytes transformed morphologically 29-51 days after 4NQO treatment and 41-61 days after MCA treatment and began to grow continuously in vitro. Cultures of transformed cells, like transformed fibroblasts. Untreated cells and cells treated with dimethyl sulfoxide did not transform within at least 110 days after inoculation. Among the transformed cells, one near-diploid cell line preserved the distinct phenotypic expression of chondrocytes, whereas heteroploid cell lines lost their differentiated features. The near-diploid cell line produced nodules in the cheek pouches of hamsters within a week, by the nodules regressed later. They showed the chondrogenic properties of the original cells and stained metachromatically with toluidine blue. Heteroploid cell lines formed progressive tumors with few chondrogenic features; these tumors were diagnosed as fibrosarcomas.

Cloning and sequencing of novel genes from Vibrio alginolyticus that support the growth of K+ uptake-deficient mutant of Escherichia coli.

Novel genes that functionally complement the growth of K+ uptake-deficient mutant strain of Escherichia coli TK420 have been cloned from the marine bacterium Vibrio alginolyticus. The nucleotide sequence revealed three open reading frames. The second gene was homologous to proC gene and allowed the growth of proC-defective mutant strain of E. coli chi 342 in the absence of proline. The first and third genes, but not proC, were required for the growth of TK420 in a synthetic medium containing 10 mM K+ and 100 mM Na+. Since K+ uptake activity of TK420 was restored by the introduction of these genes, these two genes were considered to be directly related to K+ transport. Homologous genes were found in E. coli, but their functions have not been reported.

Subunit structure of the mouse epidermal keratin filament.

The two proteins which are the subunits of mouse epidermal keratin filaments have been isolated from fully differentiated epidermis (stratum corneum), viable differentiating cells and cells grown in culture. The proteins have molecular weights of 68 000 and 60 000, consist of families of very similar species, have common N-terminal (N-acetylserine) and C-terminal (glycine) residues, contain 35--40% alpha-helix and are immunologically cross-reacting. In mixtures, the two proteins polymerize in vitro into native-type keratin filaments that are 70--80 angstrom in diameter, up to 30 micrograms long, possess a characteristic alpha-type X-ray diffraction pattern and contain the subunits in the precise molar ratio of 1 : 2 or 2 : 1.

Expression of endothelial cell-associated molecules in AML cells.

Recently, it has been clarified that interaction between hematopoietic cells and endothelial cells is important in normal hematopoiesis and leukemogenesis. In this study, we examined the relationship between AML cells and endothelial cells by analyzing the expression profile of angiogenic factors, angiopoietin-1 (Ang-1), Ang-2, Tie-2 (a receptor for angiopoietins) and vascular endothelial growth factor (VEGF). Our results demonstrated that CD7(+)AML expressed Ang-2 mRNA frequently and integrin-family adhesion molecules (CD11c and CD18) intensively, suggesting the close correlation with endothelial cells. On the other hand, in t(8;21) AML cells, expression of Ang-2 was infrequent and expression of integrin-family adhesion molecules (CD11b, CD11c and CD18) was weak, suggesting the sparse association with endothelial cells. As for CD7(+)AML cells, despite the frequent and intense expression of endothelial cell-associated molecules (such as Ang-2, CD11c and CD18), intensity of Tie-2 expression was quite low (P < 0.05). Ang-2 expressed in CD7(+)AML cells is not considered to act in an autocrine fashion, but to work on endothelial cells to "feed" leukemic cells. Although Ang-2 is recognized as a natural antagonist for Tie-2, our data presented here suggested the alternative role of Ang-2 in the relationship between endothelial cells and leukemia cells, at least in a subset of leukemia such as CD7(+)AML. These results were supported by the study using AML cell lines, KG-1 (CD7 negative) and its subline KG-1a (CD7 positive); KG-1 had mRNA expression profile of Ang-1(+)Ang-2(-)Tie-2(+), while KG-1a showed Ang-1(+)Ang-2(+)Tie-2(-). These difference in the expression profile of angiogenic factors between CD7(+)AML and t(8;21)AML may explain the characteristic morphological features of these leukemias (CD7(+)AML as blastic type and t(8;21)AML as differentiative type).

Salt-inducible kinase is involved in the ACTH/cAMP-dependent protein kinase signaling in Y1 mouse adrenocortical tumor cells.

The involvement of salt-inducible kinase, a recently cloned protein serine/threonine kinase, in adrenal steroidogenesis was investigated. When Y1 mouse adrenocortical tumor cells were stimulated by ACTH, the cellular content of salt-inducible kinase mRNA, protein, and enzyme activity changed rapidly. Its level reached the highest point in 1-2 h and returned to the initial level after 8 h. The mRNA levels of cholesterol side-chain cleavage cytochrome P450 and steroidogenic acute regulatory protein, on the other hand, began to rise after a few hours, reaching the highest levels after 8 h. The salt-inducible kinase mRNA level in ACTH-, forskolin-, or 8-bromo-cAMP-treated Kin-7 cells, mutant Y1 with less cAMP-dependent PKA activity, remained low. However, Kin-7 cells, when transfected with a PKA expression vector, expressed salt-inducible kinase mRNA. Y1 cells that overexpressed salt-inducible kinase were isolated, and the mRNA levels of steroidogenic genes in these cells were compared with those in the parent Y1. The level of cholesterol side-chain cleavage cytochrome P450 mRNA in the salt-inducible kinase-overexpressing cells was markedly low compared with that in the parent, while the levels of Ad4BP/steroidogenic factor-1-, ACTH receptor-, and steroidogenic acute regulatory protein-mRNAs in the former were similar to those in the latter. The ACTH-dependent expression of cholesterol side-chain cleavage cytochrome P450- and steroidogenic acute regulatory protein-mRNAs in the salt-inducible kinase-overexpressing cells was significantly repressed. The promoter activity of the cholesterol side-chain cleavage cytochrome P450 gene was assayed by using Y1 cells transfected with a human cholesterol side-chain cleavage cytochrome P450 promoter-linked reporter gene. Addition of forskolin to the culture medium enhanced the cholesterol side-chain cleavage cytochrome P450 promoter activity, but the forskolin-dependently activated promoter activity was inhibited when the cells were transfected with a salt-inducible kinase expression vector. This inhibition did not occur when the cells were transfected with a salt-inducible kinase (K56M) vector that encoded an inactive kinase. The salt-inducible kinase's inhibitory effect was also observed when nonsteroidogenic, nonAd4BP/steroidogenic factor-1 -expressing, NIH3T3 cells were used for the promoter assays. These results suggested that salt-inducible kinase might play an important role(s) in the cAMP-dependent, but Ad4BP/steroidogenic factor-1-independent, gene expression of cholesterol side-chain cleavage cytochrome P450 in adrenocortical cells.

Growth and differentiation of smooth muscle cells during vascular development.

Vascular smooth muscle cells have been the subject of intense study because of their importance in vascular disease process. Although significant progress has been made toward defining the various growth factors affecting the smooth muscle phenotype, very little is known about factors that promote smooth muscle differentiation. In the past few years, a number of key advances have been made in our understanding of skeletal muscle myogenesis, with the discovery of myogenic determination genes. In spite of these advances, the development and differentiation of smooth muscle cells remain vastly underexplored. This review is an attempt to understand the current status of the field and to highlight some of the recent progress made toward this goal.

Electron microscopic identification of the intracellular secretion pathway of human G-CSF in a human tumor cell line: a comparative study with a Chinese hamster ovary cell line (IA1-7) transfected with human G-CSF cDNA.

Using monoclonal antibodies specific for human granulocyte colony-stimulating factor (G-CSF), intracellular localization of G-CSF in a G-CSF-producing human tumor cell line (CHU-2) and its ultrastructural characters were described and compared with those of a Chinese hamster ovary cell line (IA1-7) transfected with human G-CSF cDNA. The CHU-2 line, which was derived from a poorly differentiated squamous cell carcinoma of the oral cavity, preserved the character of a poorly differentiated squamous cell carcinoma. In the CHU-2 cell line, there were few cells immunohistochemically positive for G-CSF under light microscopic analysis despite the high transcription level of G-CSF cDNA and secretion of G-CSF that were comparable with cDNA-transfected IA1-7 cells. Using electron microscopy, the reaction products were localized mainly in the perinuclear space (PNS) and rough endoplasmic reticula (RER) without dilation of the cisternae, but they were very rarely found in the Golgi complex and not at all in other intracellular organelles. In contrast, most cells were positive for G-CSF in the IA1-7 cell line. Reaction products in this cell line were also demonstrated in the PNS and RER without dilation of the cisternae. These immunohistochemical findings, in conjunction with the results of Western and Northern blot analysis, suggested that G-CSF was secreted via the PNS and RER without intracellular retention.

Injection of CD4(+) and CD8(+) cells with donor or host accessory cells induces acute graft-vs-host disease in human skin in immunodeficient mice.

OBJECTIVE: We examined cell subsets with respect to cutaneous graft-vs-host disease by cell sorting selection of subsets of human mononuclear cells and injecting the subsets subcutaneously in a mouse model. MATERIALS AND METHODS: Cell suspensions containing cultured human epidermal cells and dermal fibroblasts from a single donor mixed with lymphoid cell subsets positively selected using the FACSVantage cell sorting instrument and/or MACS cell isolation kits from unrelated individuals were injected into immunodeficient mice. This model is known to generate human skin with histologic findings similar to human graft-vs-host disease. RESULTS: Donor T-cell subsets CD4(+) and CD8(+) plus either host or donor CD14(+) cells were necessary to cause acute cutaneous graft-vs-host disease. Although graft-vs-host disease can result from recognition of class I antigens expressed on human cutaneous cells by donor peripheral blood mononuclear cells, additional recognition of class II antigens expressed on host mononuclear cells resulted in more severe histologic manifestations. Dendritic cells that differentiated from donor and host monocytes also showed competent accessory cell function in this system. CONCLUSIONS: Based on this model, human cutaneous graft-vs-host disease was caused by donor CD4(+) cells and CD8(+) cells activated through recognition of host antigens, including class I and class II antigens presented by either donor or host CD14(+) cells or dendritic cells.

Parathyroid hormone has a positive inotropic action in the rat.

Parathyroid hormone (PTH: synthetic bovine, amino terminus 1-34 amino acids) demonstrates a positive inotropic action on the isolated papillary muscle of the rat heart. The effect was evident at PTH concentration of 10(-12)M, and the maximum inotropic effect occurred with PTH concentrations greater than 10(-11)M. Biologically inactive PTH (PTH treated with H2O2) was without effect. The inotropic effect of PTH was partially blocked by propranolol and also suppressed in the papillary muscle of the rat pretreated with reserpine. Methoxyverapamil completely blocked the inotropic action of PTH. PTH was without effects on adenylate cyclase activity of the myocardium. Results show the presence of an inotropic action of PTH in vitro and suggest that this action of PTH is partially mediated by releasing the endogenous myocardial norepinephrine which exerts a positive inotropic effect via beta-adrenergic stimulation and by an increase in Ca++ influx across plasma membranes, but independent of adenylate cyclase activation. The inotropic action of PTH may be of significance in normal cardiac function.

Serum concentration of 20K human growth hormone (20K hGH) measured by a specific enzyme-linked immunosorbent assay. Study Group of 20K hGH.

Several GH isoforms have been identified in pituitary and serum, the most abundant of which is the 22K human GH (hGH) isoform. The 20K hGH isoform is produced by alternative splicing of GH messenger ribonucleic acid and comprises approximately 10% of all GH in the pituitary. The physiological role of 20K hGH remains to be determined, partly because of the lack of a simple and specific assay. We have established sensitive enzyme-linked immunosorbent assays (ELISAs) specific to 20K and 22K hGH. To determine whether regulation of 20K hGH secretion is the same as that for 22K hGH, we measured serum concentrations of both species of hGH in normal subjects and patients with a variety of endocrine disorders. The serum levels of 20K hGH after overnight fasting was 118 +/- 178 pg/mL (n = 282) in normal women, significantly higher than that in normal men (64 +/- 170 pg/mL; n = 226). However, there was no difference in the proportion of 20K hGH to 20K plus 22K hGH between men (6.3 +/- 2.6%, mean +/- SD; n = 176) and women (6.3 +/- 2.1%; n = 263). No correlation was detected between the ratio of 20K hGH and age, body height, body weight, or body fat mass in normal subjects. The proportion of 20K hGH was significantly (P < 0.001) higher in patients with active acromegaly (9.2 +/- 2.2%; n = 33) and patients with anorexia nervosa (9.0 +/- 1.9; n = 8), both of which are characterized by chronic elevation of circulating GH levels. The proportion of 20K hGH in successfully treated acromegalic patients did not differ from that in normal subjects, suggesting that GH-producing pituitary tumors secrete a higher proportion of 20K hGH, or that a chronic excess of 22K hGH alters the MCR of 20K hGH. The values in patients with adult GH deficiency, hyperthyroidism, primary hypothyroidism, or GH-independent short stature did not differ from those in normal subjects. The 20K ratio did not change after acute GH provocative tests, such as the insulin tolerance test and the GHRH test. These results suggest that secretion of 20K hGH from the pituitary is under the same control as that of 22K hGH. This new assay may provide a tool for understanding the physiological or pathophysiological role of the 20K hGH isoform.

The GABAergic neurons and axon terminals in the lateralis medialis-suprageniculate nuclear complex of the cat: GABA-immunocytochemical and WGA-HRP studies by light and electron microscopy.

In order to get more detailed information on the neural circuit of the lateralis medialis-suprageniculate nuclear (LM-Sg) complex of the cat, the GABAergic innervation of this complex was studied by GABA immunohistochemical techniques. Small immunoreactive cells were found throughout the LM-Sg complex. On the basis of their ultrastructural features, these GABAergic cells were identified as Golgi type II interneurons. The neuropil of this nucleus displayed a conspicuous granular immunoreactivity. Ultrastructurally, the immunoreactive neural profiles in the neuropil were identified as the presynaptic dendrites of interneurons, myelinated axons, or axon terminals. The GABAergic dendritic profiles, containing pleomorphic synaptic vesicles, were involved in synaptic glomeruli. Additionally, GABAergic axon terminals containing pleomorphic synaptic vesicles formed symmetric axodendritic synaptic contacts mainly in the extraglomerular neuropil. They appeared to correspond to either axon terminals from the thalamic reticular nucleus (TRN) or the axon terminals of interneurons. The projections from the TRN to the LM-Sg complex were studied by using wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP). Following injection of WGA-HRP into the LM-Sg complex, a number of retrogradely labeled cells were observed in the TRN. The connections between the TRN and the LM-Sg complex appeared to be topographically organized, the dorsal TRN being connected mainly with the dorsomedial portion of the LM-Sg complex, and the ventral TRN being connected chiefly with the ventrolateral portion of the LM-Sg complex. Following injection of the tracer into the TRN, ultrastructural examination of anterograde labeling in the LM-Sg complex revealed that labeled terminals contain pleomorphic vesicles and make symmetric synaptic contacts mainly with small to medium-sized dendrites. The labeled terminals were not involved in synaptic glomeruli. The present results provide anatomic support for the contention that the projection cells of the LM-Sg complex may be inhibited by both the TRN axons and interneurons, probably through the mediation of GABA.

Organization of the colliculo-suprageniculate pathway in the cat: a wheat germ agglutinin-horseradish peroxidase study.

A wheat germ-agglutinated horseradish peroxidase (WGA-HRP) tracing technique was used to label the cell bodies of neurons in the superior colliculus that send projections into the visually sensitive region of the suprageniculate nucleus (Sg) in the feline thalamus. After determination of the position of the Sg by detecting characteristic single-unit responses to moving visual stimuli, WGA-HRP was injected into the Sg in five pentobarbital-anesthetized cats. The animals were than sacrificed, and serial frozen sections of the midbrain were processed for the demonstration of peroxidase activity. A total of 2,736 WGA-HRP-stained neurons were located within the ipsilateral superior colliculus (SC), and a few labeled cells were consistently found bilaterally in the external nuclei of the inferior colliculus. In each cat, a small but significant fraction of the labeled cells were encountered contralateral to the injection. Medial SC neurons tended to project to the posterior Sg, and lateral SC neurons tended to project to more rostral Sg. However, labeled cells were distributed homogeneously along the rostrocaudal extent of the SC, indicating the absence of a well defined topographic relationship. Nor was the Sg injection site location related to the laminar distribution of SC projection neurons. In all cases, the majority of the labeled cells were found in layer IV (49.0%), with fewer cells in layers III (17.5%) layer V (20.0%), and layer VI (11.8%). No labeled cells were located in layer I, although a few were located in the deep part of layer II. Five types of SC projection cells were distinguished morphologically. Of the 258 labeled cells that could be characterized, 25% were stellate cells, 25% vertical cells, 20% granular cells, 17% triangular cells, and 12% horizontal cells. The average diameter of 226 cells ranged between 8 and 47 microns. We conclude that a mixed population of SC cells projects to the Sg; the morphological heterogeneity and the distribution of these cells suggests that several functionally different pathways may be involved in the colliculothalamic pathway and in the processing of visual input in the SC.

Effects of ethane-1-hydroxy-1, 1-diphosphonate on cell differentiation, and proteoglycan and calcium metabolism, in the proximal tibia of young rats.

The effects of ethane-1-hydroxy-1, 1-diphosphonate(EHDP) on cell differentiation, and on the metabolism of proteoglycan and calcium in the epiphyseal plate and metaphysis of rats were investigated through histology and autoradiograms of [35S]-sulfate, 45Ca, and [3H]-thymidine. Suppression of bone resorption in the metaphysis due to low dose EHDP administration was associated with a proliferation of osteoclasts with an increased number of nuclei. High dose EHDP induced enlargement of the hypertrophic zone of the epiphyseal plate and suppression of calcification of the cartilage matrix. This change had a significant association not only with the suppression of chondroitin sulfate synthesis and the degradation in the cartilage matrix, but also with the suppression of growth and differentiation of chondrocytes. Calcification was also inhibited in the metaphysis, and growth and differentiation from undifferentiated mesenchymal cells to osteoblasts, osteocytes, and osteoclasts were also suppressed by high dose EHDP.