Analysis of proliferating biliary epithelial cells in human liver disease using a monoclonal antibody against DNA polymeraseα

The proliferative activity and ultrastructural characteristics of proliferating biliary epithelial cells were analysed immunohistocytochemically in 39 biopsied liver specimens from patients with acute viral hepatitis, chronic hepatitis and liver cirrhosis using a monoclonal antibody against DNA polymerase (DNA-PA). In acute viral hepatitis with perivenular confluent necrosis, proliferation of typical bile ducts was found frequently in portal areas. In chronic aggressive hepatitis and cirrhosis, ductular proliferation of both typical and atypical forms was found in enlarged portal and periportal areas and in confluent necrotic areas. The number of proliferating biliary epithelial cells that stained positive for DNA-PA was small. There were very few positively stained cells in atypical bile ducts in confluent necrotic areas of cirrhosis. Atypical bile ducts seen in chronic aggressive hepatitis, cirrhosis and acute hepatitis with confluent necrosis were positively stained for both cytokeratins 8 and 19. In cirrhosis, the number of stained biliary epithelial cells in typical bile ducts was larger than the number of such cells in atypical bile ducts (P< 0.01). By electron microscopy, the cells positively stained for DNA-PA were mostly so-called clear cells with irregular nuclei containing coarse nucleoplasm, and a few small cells with scanty cytoplasm and few organelles.     

Topical application of FK506 (tacrolimus) ointment inhibits mite antigen-induced dermatitis by local action in NC/Nga mice

BACKGROUND: FK506 ointment (tacrolimus ointment, protopic) is a new drug therapeutically effective for patients with atopic dermatitis (AD). However, the mechanism of action of FK506 ointment on AD is not fully understood. METHODS: We examined the effect of FK506 ointment on mite antigen-induced dermatitis in NC/Nga mice. Clinical symptoms and ear thickness were recorded, and histopathological studies and in vitro analyses were performed. RESULTS: Topical application of FK506 ointment (0.03-0.3%) suppressed the development of dermatitis. In the lesional skin, both interleukin (IL)-4 and interferon (IFN)-gamma were detected, even though the IL-4+/IFN-gamma- T helper 2 (Th2) population was predominant in the regional lymph nodes (LNs). Topical application of FK506 treatment reduced the elevated level of both IL-4 and IFN-gamma in the skin, but did not decrease the expansion of the Th2 population in the LNs. CONCLUSIONS: Topical application of FK506 ointment suppresses dermatitis by inhibiting the activation of inflammatory cells locally, without systemic immune suppression, in this AD model.     

Atypical Glomus Tumor in the Mediastinum: A Case Report with Immunohistochemical and Ultrastructural Studies

A case is reported of atypical glomus tumor occurring in the posterior inferior mediastinum of a 26-year-old woman complaining of severe back pain. The tumor was composed of atypical small, round tumor cells with scattered mitotic figures. In addition to sheet-like, diffuse proliferation of the tumor cells, some areas of the tumor contained small “glo-moid” cells arranged in organoid and hemangiopericytoma-like patterns. Immunohistochemically, many tumor cells were positive for muscle-type actins and a few cells were focally positive for desmin. Ultrastructural studies revealed smooth muscle features of tumor cells, that is, pinocytotic vesicles, external laminas, dense plaques, and occasional thin filaments with dense bodies. The patient remained well for 5 years and 4 months after the operation without additional radiation and chemotherapy. The tumor was diagnosed as an atypical, or low-grade malignant, glomus tumor morphologically. It seems important to recognize the presence of this type of tumor in sites other than extremities and to differentiate it from other malignant small, round cell tumors.     

A tctex1-Ca2+ channel complex for selective surface expression of Ca2+ channels in neurons

Voltage-gated Ca(2+) channels (VGCCs) are important in regulating a variety of cellular functions in neurons. It remains poorly understood how VGCCs with different functions are sorted within neurons. Here we show that the t-complex testis-expressed 1 (tctex1) protein, a light-chain subunit of the dynein motor complex, interacts directly and selectively with N- and P/Q-type Ca(2+) channels, but not L-type Ca(2+) channels. The interaction is insensitive to Ca(2+). Overexpression in hippocampal neurons of a channel fragment containing the binding domain for tctex1 significantly decreases the surface expression of endogenous N- and P/Q-type Ca(2+) channels but not L-type Ca(2+) channels, as determined by immunostaining. Furthermore, disruption of the tctex1-Ca(2+) channel interaction significantly reduces the Ca(2+) current density in hippocampal neurons. These results underscore the importance of the specific tctex1-channel interaction in determining sorting and trafficking of neuronal Ca(2+) channels with different functionalities.     

Monosynaptic inputs from the nucleus tractus solitarii to the laryngeal motoneurons in the nucleus ambiguus of the rat

The cricothyroid (CT) and the posterior cricoarytenoid (PCA) muscles in the larynx are activated by the laryngeal motoneurons located within the nucleus ambiguus; these motoneurons receive the laryngeal sensory information from the nucleus tractus solitarii (NTS) during respiration and swallowing. We investigated whether the neurons in the NTS projected directly to the laryngeal motoneurons, and what is the synaptic organization of their nerve terminals on the laryngeal motoneurons using the electron microscope. When wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) was injected into the NTS after cholera toxin subunit B-conjugated HRP (CT-HRP) was injected into the CT muscle or the PCA muscle, the anterogradely WGA-HRP-labeled terminals from the NTS were found to directly contact the retrogradely CT-HRP-labeled dendrites and soma of both the CT and the PCA motoneurons. The labeled NTS terminals comprised about 4% of the axosomatic terminals in a section through the CT motoneurons, and about 9% on both the small (PCA-A) and the large (PCA-B) PCA motoneurons. The number of labeled axosomatic terminals containing round vesicles and making asymmetric synaptic contacts (Gray’s type I) was almost equal to that of the labeled terminals containing pleomorphic vesicles and making symmetric synaptic contacts (Gray’s type II) on the CT motoneurons. The labeled axosomatic terminals were mostly Gray’s type II on the PCA-A motoneurons, while the majority of them were Gray’s type I on the PCA-B motoneurons. These results indicate that the laryngeal CT and PCA motoneurons receive a few direct excitatory and inhibitory inputs from the neurons in the NTS. Accepted: 2 June 2000     

Effect of maximal arm exercise on skin blood flux in the paralyzed lower limbs in persons with spinal cord injury

 The purpose of the present study was to examine the effect of maximal arm exercise on the skin blood circulation of the paralyzed lower limbs in persons with spinal cord injury (PSCI). Eight male PSCI with complete lesions located between T3 and L1 performed graded maximal arm-cranking exercise (MACE) to exhaustion. The skin blood flux at the thigh (SBFT) and that at the calf (SBFC) were monitored using laser-Doppler flowmeter at rest and for 15 s immediately after the MACE. The subject's mean peak oxygen uptake and peak heart rate was 1.41 ± 0.22 l · min^–1 and 171.6 ± 19.2 beats · min^–1, respectively. No PSCI showed any increase in either SBFT or SBFC after the MACE, when compared with the values at rest. These results suggest that the blood circulation of the skin in the paralyzed lower limbs in PSCI is unaffected by the MACE. Accepted: 12 September 1996     

The plasminogen activation system reduces fibrosis in the lung by a hepatocyte growth factor-dependent mechanism

Mice deficient in the plasminogen activator inhibitor-1 gene (PAI-1-/- mice) are relatively protected from developing pulmonary fibrosis from bleomycin administration. We hypothesized that one of the protective mechanisms may be the ability of the plasminogen system to enhance hepatocyte growth factor (HGF) effects, which have been reported to be anti-fibrotic in the lung. HGF is known to be sequestered in tissues by binding to extracellular matrix components. Following bleomycin administration, we found that HGF protein levels were higher in bronchoalveolar lavage fluid from PAI-1-/- mice compared to wild-type (PAI-1+/+) mice. This increase could be suppressed by administering tranexamic acid, which inhibits plasmin activity. Conversely, intratracheal instillation of urokinase into bleomycin-injured PAI-1+/+ mice to activate plasminogen caused a significant increase in HGF within bronchoalveolar lavage and caused less collagen accumulation in the lungs. Administration of an anti-HGF neutralizing antibody markedly increased collagen accumulation in the lungs of bleomycin-injured PAI-1-/- mice. These results support the hypothesis that increasing the availability of HGF, possibly by enhancing its release from extracellular matrix by a plasmin-dependent mechanism, is an important means by which activation of the plasminogen system can limit pulmonary fibrosis.     

Hepatische Extraktion und Clearance von Renin bei Lebercirrhosen

Zusammenfassung Bei 14 kompensierten und 8 dekompensierten Lebercirrhosen wurden Vergleichsbestimmungen der Renin-Aktivität (RA) im arteriellen und Lebervenenblut (Methode Kaneko et al.) durchgeführt. Die errechnete hepatische Renin-Extraktion (HE %) ist im Gegensatz zu Befunden anderer bei Cirrhosekranken nicht aufgehoben. Die Einzelwerte sind weit gestreut, die HE beträgt bei kompensierten Cirrhosen durchschnittlich 17,8±17,3%, bei dekompensierten Cirrhosen 30,5±5,8%. Ein signifikanter Unterschied der HE zu einer Vergleichsgruppe Hochdruckkranker (Mittelwert 28,5±20,4%,n=20) besteht nicht (p>0,05 bzw.>0,4).Aus den bei der Mehrzahl der Cirrhosekranken durchgeführten Bestimmungen leberhämodynamischer Größen geht hervor, daß die Renin-Extraktion der Tendenz nach mit dem Lebervenenverschlußdruck ansteigt (r=–0,393,p>0,05). Zum hepatischen Plasmafluß, bestimmt mit der Indocyaningrün-Methode, ergibt sich eine umgekehrte, statistisch allerdings nicht gesicherte Beziehung (r=–0,427,p>0,05). Es wird geschlossen, daß die hepatische Extraktion von Renin bei Lebercirrhosen vermutlich durch die intrahepatische Passagezeit beeinflußt wird.Unter Berücksichtigung der für die Vergleichsgruppe errechneten hepatischen Renin-Clearance (HRC) von 292±178 ml/min ist die HRC bei kompensierten Cirrhosen auf 68%, bei dekompensierten Cirrhosen auf 42,5% herabgesetzt. Im Rahmen der komplexen Regulationsstörung des Renin-Angiotensin-Systems bei fortgeschrittenen Lebercirrhosen dürften danach nicht allein Änderungen der renalen Sekretion, sondern außerdem eine Einschränkung der hepatischen Renin-Clearance für die Aufrechterhaltung einer erhöhten Plasma-Enzym-Aktivität von Bedeutung sein.     

Renin-Substrat-(Angiotensinogen-)Konzentration im maternen und fetalen Blut

Zusammenfassung Bei 18 Schwangeren wurden unter der Geburt Vergleichsbestimmungen der Angiotensinogen-Konzentration und der Renin-Aktivität (modifiz. Methode nach Kaneko) im mütterlichen peripher-venösen und Nabelschnurblut durchgeführt.Im fetalen Serum ist die Angiotensinogen-Konzentration auf durchschnittlich 1440 ± 543 ng/ml gegenüber 3622 ± 1312 ng/ml im mütterlichen Serum (p<0,001) herabgesetzt. Dagegen liegt der fetale Angiotensinogengehalt, bezogen auf die Erwachsenen-Werte Nichtgravider (1115 ± 178 ng/ml) um 39% (p<0,05) erhöht.Die Renin-Aktivität ist im mütterlichen Serum mit 15,7 ± 8,7 ng/ml/4 Std signifikant (p<0,05) gegenüber dem fetalen Blut (31,4 ± 28,2 ng/ml/4 Std) herabgesetzt.Es wird geschlossen, daß die fetale Leber in hohem Maße Angiotensinogen synthetisieren kann. Der mögliche stimulierende Einfluß mütterlicher oder placentarer Oestrogene auf die hepatische Biosynthese wird erörtert. Unter Berücksichtigung des Konzentrationsgradienten ist mit einem placentaren Übertritt von Angiotensinogen zur fetalen Seite nur in geringem Maße zu rechnen.