C CELL CARCINOMA OF THE THYROID

Two cases of papillary type of C cell carcinoma of the thyroid were reported. They showed papillary arrangement with Abrovascular stalk in properly Axed tissues. Histochemically argyrophil reaction was positive in the cytoplasm and amyloid deposited in the stroma. Ultrastructurally secretory granules were found in their cytoplasm. The papillary type is not an artifact but one of the histologic variations of this carcinoma. ACTA PATH. SAP. 29: 653–659, 1979.     

Features of 4-aminopyridine sensitive outward current observed in single smooth muscle cells from the rabbit pulmonary artery

The 4-aminopyridine (4AP) sensitive outward current of enzymatically dispersed single smooth muscle cells of the rabbit main pulmonary artery were investigated using the voltage clamp method. When the cell was exposed to physiological salt solution (PSS) in the bath and high K⁺ in the pipette no inward current was generated by depolarization of the membrane, but when 4AP was present in the bath or when Cs⁺ with tetraethylammonium⁺ (Cs⁺-TEA⁺) in the pipette, an inward current was generated. This current was enhanced by Ba²⁺ or high Ca²⁺ and was blocked by inorganic or organic Ca²⁺ channel blockers.The outward current was partly inhibited by the Ca²⁺ channel blockers, Ca²⁺-free or Mn²⁺ containing solution. The residual outward current was blocked by external application of 10 mM 4AP, whereas it was inhibited by half with 100 mM TEA⁺. To investigate further natures of 4AP sensitive outward current, the following experiments were done in the bath solution containing 2.5 mM Mn²⁺. The reversal potential of this outward current, estimated from the tail current, remained the same in Na⁺-deficient solution, but shifted to near the K⁺-equilibrium potential in Cl^– deficient solution. Thus, the main current carrier for the outward current seems to be K⁺, but Cl^– may participate to some extent. The amplitude of the outward current decreased slowly. However, the reversal potential was not changed, suggesting the reduction in amplitude of the outward current was not due to the accumulation of K⁺ on the outer surface of the membrane. As 4AP inhibited the outward current to a greater extent at lower than higher membrane potential levels, 4AP bound to the channel may be dislodged at higher levels. When pH of the bath solution was modified from 7.3 to 8.0, inhibitory actions of 4AP were enhanced (pKa value of 4AP=9.17). Thus, a non-ionized form of 4AP may act as a channel blocker. We conclude that in smooth muscle cells of the pulmonary artery, lack of an action potential in physiological solution may partly be due to a small inward current as well as a large contribution of the 4AP sensitive outward current.     

Observation of cavitation in a mechanical heart valve in a total artificial heart

Recently, cavitation on the surface of mechanical heart valves has been studied as a cause of fractures occurring in implanted mechanical heart valves. The cause of cavitation in mechanical heart valves was investigated using the 25 mm Medtronic Hall valve and the 23 mm Omnicarbon valve. Closing of these valves in the mitral position was simulated in an electrohydraulic totally artificial heart. Tests were conducted under physiologic pressures at heart rates from 60 to 100 beats per minute with cardiac outputs from 4.8 to 7.7 L/min. The disk closing motion was measured by a laser displacement sensor. A high-speed video camera was used to observe the cavitation bubbles in the mechanical heart valves. The maximum closing velocity of the Omnicarbon valve was faster than that of the Medtronic Hall valve. In both valves, the closing velocity of the leaflet, used as the cavitation threshold, was approximately 1.3-1.5 m/s. In the case of the Medtronic Hall valve, cavitation bubbles were generated by the squeeze flow and by the effects of the venturi and the water hammer. With the Omnicarbon valve, the cavitation bubbles were generated by the squeeze flow and the water hammer. The mechanism leading to the development of cavitation bubbles depended on the valve closing velocity and the valve stop geometry. Most of the cavitation bubbles were observed around the valve stop and were generated by the squeeze flow.     

Hepatocellular carcinoma and myocardial sarcoidosis.--An autopsy case.

An autopsy case of a 65-year-old male who died of hepatocellular carcinoma superimposed on liver cirrhosis complicated with systemic sarcoidosis is presented. No organ metastasis of hepatocellular carcinoma was found except for a minute tumor embolus in the left upper lobe of the lung. Involved organs by sarcoidosis were the lymph nodes, lungs, heart, liver and spleen, but its presence was not noticed before death. Its cardiac involvement coincide with his clinical symptom of exertional dyspnea and the ECG finding of A-V block.     

Expression of cyclin D1, retinoblastoma gene protein, and p16 MTS1 protein in atypical adenomatous hyperplasia and adenocarcinoma of the lung

 To clarify the events leading to the disruption of cell growth control that occurs during the development of pulmonary adenocarcinoma (AC), we used immunohistochemistry to evaluate the expression of G1 cycle regulators, cyclin D1, Rb protein (pRb), and p16 MTS1 protein and the tumour proliferation marker, Ki 67, both in AC of the lung and in its precursor lesion, atypical adenomatous hyperplasia (AAH). The frequency of lesions with cyclin D1 overexpression was relatively high in AAH (47–89%), but was decreased in early AC (28%) and overt AC (35%). The loss of pRb expression was rare in both AAH (0–18%) and early AC (0%), and was infrequent even in overt AC (13%). The loss of p16 expression was also relatively infrequent in both the premalignant and the malignant lesions (11–25%). Our results suggest that overexpression of cyclin D1 is an early event and plays an important part in tumorigenesis in the case of lung AC. However, cyclin D1 overexpression is not required for the development and maintenance of a malignant phenotype. It is likely that some cyclin D1-independent pathways other than Rb and p16 abnormalities have an important role in the malignant transformation from AAH to early AC. Received: 8 July 1997 / 26 September 1997     

Sensory inputs from the oral region to the cerebral cortex in behaving rats: an analysis of unit responses in cortical somatosensory and taste areas during ingestive behavior

1. The responses of 90 cortical neurons in the somatosensory and gustatory areas were recorded with chronically implanted fine wires in freely moving Wistar rats. The responses were analyzed mainly while the animals were freely licking solutions and eating dry pellets. Cortical neurons were classified into several groups according to their response properties. 2. "Mechanosensitive" neurons (n = 20) showed rhythmic phasic activity in different phases of the licking cycle, depending on the location of their receptive field in the peripheral orofacial region. 3. "Movement-related" neurons (n = 27) changed their activities tonically during licking, chewing, or grooming behavior. The responses were either excitatory or inhibitory. Receptive fields and adequate stimuli could not be identified. These neurons might receive somatosensory (except light tactile) inputs from wide or deep areas of intra- or perioral regions, or might be related to orofacial active movement. 4. "Taste" neurons (n = 35) increased or decreased their discharge rates during licking of particular taste solutions. Some taste neurons received convergence from somatosensory inputs. 5. "Temperature" neurons (n = 2) responded exclusively to water of temperatures lower or higher than room temperature. The responses were opposite in direction between cold and warm stimuli. 6. "Anticipation" neurons (n = 4) increased their impulse discharges before the start of licking in the situation in which the animal expected access to the drinking tube. 7. "Attention" neurons (n = 2) responded to arousal stimulation such as sound, a flash of light, and body touch. These neurons showed only a slightly increasing response during ingestive behavior. 8. The locations of 56 of 90 units were histologically identified. Mechanosensitive neurons were located in the appropriate parts of the somatotopic pattern within the primary somatic sensory area in the granular cortex. Taste neurons were found evenly in the dysgranular cortex and the agranular insular cortex. Other types of neurons were located mainly in the dysgranular cortex between the granular cortex and agranular insular cortex, and some were intermingled with taste neurons in the agranular insular cortex. 9. The present study has shown that cortical neurons in the orolingual somatosensory and taste areas have different response characteristics related to each aspect of ingestive behavior.(ABSTRACT TRUNCATED AT 400 WORDS)     

PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATHY

Clinical, light- and electron microscopic, and immunohistochemical findings of a 44-year-old woman with progressive multifocal leukoencephalopathy were presented. Autopsy revealed a wide distribution of the demyelinating lesion in the cerebrum, cerebellum, brain stem and spinal cord, and intranuclear inclusion bodies and papova-like virions in transmission electron microscopy in the nuclei of oligodendrocytes. SV40 antigen was immunohistochemically detected in these inclusion bodies. The widespread extension of the lesions seemed to correlate with the duration of the patient's illness. The prolongation of the clinical course in this case may be dependent upon the lack of serious underlying diseases except for a small nodule of thyroid carcinoma, SV40 infection rather than JC virus infection and/or improved care of that kind of patient.     

Mesp1-nonexpressing cells contribute to the ventricular cardiac conduction system.

Previous fate mapping analysis, using Cre recombinase driven by the Mesp1 locus, revealed that Mesp1 is expressed in almost all of the precursors of the cardiovascular system, including the endothelium, endocardium, myocardium, and epicardium. Mesp1-nonexpressing cells were found to be restricted to the outflow tract cushion and along the interventricular septum (IVS), which is a location that is suggestive of specialized cardiac conduction system (CCS). In our current study, we examined the identity of these IVS cells by using the pattern of beta-galactosidase activity in CCS-lacZ mice. In addition, by crossing Mesp1-Cre and floxed GFP reporter mice with CCS-lacZ mice, we have calculated that approximately 20% of the ventricular CCS within the IVS corresponds to Mesp1-nonexpressing cells. These data suggest that the ventricular CCS is of heterocellular origin. Furthermore, we indicate a possibility that a population of the cells that contribute to the ventricular CCS might be distinguished at an early stage of development.     

Adrenomedullin and proadrenomudullin N-terminal 20 peptide (PAMP) are present in human colonic epithelia and exert an antimicrobial effect

The hypotensive and vasorelaxing peptides adrenomedullin (AM) and its gene-related peptide, proadrenomedullin N-terminal 20 peptide (PAMP), were found to be distributed on the surface of the colonic mucosa. AM and PAMP showed dose-dependent antimicrobial activity against E. coli. The results suggest that the novel vasoactive peptides AM and PAMP play an important role in mucosal defence.