Pilomatrix carcinoma of the axilla: CT and MRI features.

Pilomatrix carcinoma, a rare malignant soft tissue tumour, is the malignant variant of pilomatricoma. We report a case of pilomatrix carcinoma of the axilla. CT demonstrated a well-circumscribed, sand-like calcified mass. MRI showed diffusely inhomogeneous, mixed signal intensities with inhomogeneous enhancements. The MRI findings were different from those previously reported for pilomatricoma.

Development of Dunn osteosarcoma inoculated into subcutaneous air pouch in mice.

Dunn osteosarcoma cell growth was observed in C3H/Hej mouse subcutaneous air pouch. Inoculation with Dunn osteosarcoma cell suspension was performed by injection into air pouches of 70 mice on Day 7 after the initial injection of air. The developmental pattern of the tumor cell colonies was classified histologically into five stages. In Stage 0 (stage of no tumor cells), there were no tumor cells. In Stage 1 (focal stage), the colonies were limited to the lining-cell layers. In Stage 2, (segmental stage) the colonies protruded into the cavity of the pouch. In Stage 3 (annular stage), the total surface of the inner wall of the pouch was occupied by tumor cells. In Stage 4 (occlusive stage), the cavity of the pouch was fully occupied by tumor cells. The tumor was observed to develop to stage 1 in all mice 7 days after inoculation. The colonies were all found to be settled initially in the deeper layer of lining cells. Thus, the mouse air-pouch model is useful for direct observation of osteosarcoma cell growth.

Suppressive effects of F-1322 on the antigen-induced late asthmatic response and pulmonary eosinophilia in guinea pigs.

We investigated the effects of F-1322 (N-[2-[4-(benzhydryloxy)piperidino]ethyl]-3-hydroxy-5-(3-pyridylmethoxy)-2-naphthamide), a new compound that inhibits both thromboxane A2 synthetase and 5-lipoxygenase and that functions as a histamine antagonist, on the Ascaris antigen-induced late asthmatic response and pulmonary eosinophilia in guinea pigs. Oral administration of F-1322 (10-100 mg/kg) inhibited the antigen-induced late asthmatic response in a dose-dependent manner. Histological analysis revealed that F-1322 prevented the accumulation of eosinophils in the airways and this was paralleled by a decrease in the number of eosinophils and lymphocytes recovered in bronchoalveolar lavage fluid. F-1322 (0.1-10 microM) inhibited eotaxin-induced chemotaxis and actin polymerization of eosinophils in vitro in a concentration-dependent manner, while oral administration of F-1322 dose-dependently suppressed the migration of eosinophils into the airways in vivo in response to infusion of interleukin 5 and eotaxin in combination. F-1322 may, thus, improve the late asthmatic response in this model, in part, by preventing the accumulation of eosinophils in the airways. The pharmacological profile of F-1322 indicates that this drug is likely to be useful in the treatment of allergic diseases such as asthma.

Organizing sound sequences in the human brain: the interplay of auditory streaming and temporal integration.

The present study examined the relationship between two of the early brain processes of sound organization: auditory streaming and the temporal window of integration (TWI). Presented at a fast stimulus delivery rate, two tones alternating in frequency are perceived as separate streams of high and low sounds. However, when two sounds are presented within a ca. 200 ms temporal window, they are often processed as a single auditory event. Both stream segregation and temporal integration occur even in the absence of focused attention as was shown by their effect on the mismatch negativity (MMN) event-related potential. The goal of the present study was to determine the precedence between these two sound organization processes by using the stimulus-omission MMN paradigm. Infrequently omitting one stimulus from a homogeneous tone sequence only elicits an MMN when the stimulus onset asynchrony separating successive tones is shorter than 170 ms. This demonstrates the effect of the TWI. Magnetic brain responses elicited by infrequent stimulus omissions appearing in a sequence of two alternating tones were recorded. The magnetic MMN was elicited by tone omission when the alternating tones formed a single stream (with no or only small frequency separation between the two tones) but not when separate high and low streams emerged in perception (large frequency separation between the two alternating tones). This result shows that auditory streaming takes precedence over the processes of temporal integration.

The effect of deviant stimulus probability on the human mismatch process.

The present study addresses the separate activities of frontal and temporal MMN generators which might be differentially affected by a change in the probability of standard stimuli. As the probability of standard stimuli was increased, the frontal MMN component significantly increased in amplitude, while the temporal one was not affected. Correspondingly, the scalp current density (SCD) maps showed that the temporal MMN generator was activated even at low probability of standard stimuli, suggesting that even the weak memory trace could start the automatic mismatch process, whereas the frontal MMN generator was activated only with increased probabilities of standard stimuli, suggesting that the stronger the memory trace is, the easier it might trigger the involuntary switching of attention to stimulus change.

Automatic auditory information processing in sleep.

STUDY OBJECTIVES: The mismatch negativity (MMN) component of the event-related potentials reflects the automatic detection of sound change. Only a few researchers have investigated the MMN elicitation during sleep in adult human and some of them reported that MMN amplitude was decreased in sleep compared to in waking. However, it is not clear that the decrease of MMN amplitude was due to increased drowsiness or long-term response decrement. Two experiments were conducted to clarify whether or not the MMN was elicited in each sleep stage. We presented auditory stimuli to subjects continuously from waking until sleep state (Experiment 1). Using the same experimental condition, we examined whether or not MMN amplitude was influenced by long-term stimulus presentation (80min.) and by vigilance level (Experiment 2). DESIGN: N/A SETTING: N/A PARTICIPANTS: N/A INTERVENTIONS: N/A MEASUREMENTS & RESULTS: Experiment 1: MMN was obtained in both drowsiness and REM sleep. MMN was significantly smaller in amplitude and shorter in latency in the both stages than in the waking state. However, MMN was not found in another sleep stage. Experiment 2: Amplitudes were no different among 0-20 min., 20-40 min., 60-80 min. But it was decreased in 40-60 min. and power value of alpha-wave was decreased in 40-60 min. CONCLUSIONS: To obtain the reliable data, by using the automatic spectral analysis, we confirmed that MMN was elicited in REM sleep. MMN was not influenced by long-term stimulation. The result suggested that auditory stimuli could be processed in the pre-attentive sensory memory even in REM sleep.

Mismatch negativity (MMN) reveals sound grouping in the human brain.

To investigate a part of the structure of the memory trace, auditory event-related potentials (ERPs) were recorded from reading subjects while they were presented with two different stimulus-series simultaneously. A clear mismatch negativity (MMN) was obtained from each series, when the stimulus sequence consisted of a high-frequency series and a low-frequency series. Moreover, the MMN showed independent elicitation within each series. However, if the frequency range of one series overlapped with that of the other series, the amplitude of the MMN was prominently reduced, suggesting that the two processing functions indexed by MMN coexisted simultaneously in the preattentive acoustic system and were produced by the respective grouping of high-frequency tones and low-frequency tones.

Event-related desynchronization during an auditory oddball task.

OBJECTIVE: The present study addressed what kind of mental processes would be presented by the event-related desynchronization (ERD) relevant to the stimuli of an auditory oddball count task. METHODS: Electroencephalogram (EEG) was recorded from nine healthy subjects while target tones (2000 Hz, P = 0.2) and non-target tones (1000 Hz, P = 0.8) were presented randomly with constant stimulus onset asynchrony (SOA) of 3.3 s. To improve time resolution of ERD analysis, obtained EEG epochs were digitally convoluted by Gabor wavelet and averaged respectively. RESULTS: For target stimulus, prominent ERD was observed in left parieto-occipital areas (peak latency: 400-600 ms), but there were no significant ERD for non-target stimulus. CONCLUSION: Our result suggests that magnitude of ERD would reflect amount of mental effort which was associated with intentional and voluntary processes rather than automatically sensory process.

Predictive value of serum immunosuppressive acidic protein for lung metastasis after amputation of murine osteosarcoma of the lower limb.

A spontaneously occurring murine osteosarcoma cell line (POS-1) was inoculated into the footpads of 88 mice. In 59 mice, the tumor-bearing leg was amputated at 1, 3, 5, or 7 weeks after inoculation and the mice sacrificed at 9 weeks. Lung metastasis was observed in 82.6-100% of the mice undergoing leg amputation at 5 or 7 weeks after inoculation. There were no lung metastasis in the mice amputated at 1 or 3 weeks. The serum immunosuppressive acidic protein (IAP) concentration showed a significant increase at 5 or 7 weeks after inoculation (P<0.005 and P<0.0005, respectively). When amputation was done 5 weeks after inoculation, the serum IAP concentration increased further to 5.9 times the pre-amputation level 1 week after the amputation. The IAP concentration increased only 1.3-fold in the control group without inoculation. Thus, a high serum IAP concentration before amputation and a further increase after amputation were indicators of lung metastasis in this mouse model of osteosarcoma.

Degradation of yolk platelets in the early amphibian embryo is regulated by fusion with late endosomes.

The eggs of many animal species contain a large store of yolk platelets, lipid droplets and glycogen granules; these are consumed during early embryogenesis. However, the mechanisms by which degradation of these stored materials occurs during early embryogenesis are not clearly understood. The mechanisms underlying yolk degradation in amphibian (newt) embryos were investigated. Electron microscopy using an anion marker, cationic ferritin, revealed that yolk platelets were degraded after fusion with late endosomes containing primary lysosomes. Electron microscopy and the results of experiments using a number of reagents with selective effects on intracellular transport suggested that yolk degradation activity in early amphibian embryos may be regulated at the point of fusion between late endosomes and yolk platelets.

Time integrated spectroscopy of turbid media based on the microscopic beer-lambert law: application to small-size phantoms having different boundary conditions.

Continued work on time-integrated spectroscopy (TIS) is presented to quantify absorber concentrations in turbid media. We investigated the applicability of the TIS method to small-size media that have different boundary conditions by measuring two 20×20×50 mm3 cuboid liquid tissue-like phantoms at various absorption levels (absorption coefficients of the phantom from 2.5×10-3 to 4.4×10-2 mm-1 at 782 nm and from 3.1×10-3 to 2.7×10-2 mm-1 at 831 nm). The scattering and absorbing solution was filled into ordinary and black-anodized aluminum containers to provide different boundary conditions. By means of a single equation, the absorber concentrations have been recovered within errors of a few percent in both cases. This demonstrates that the TIS method can quantify absorbers in small-size media having different boundary conditions. © 1999 Society of Photo-Optical Instrumentation Engineers.

Somatosensory automatic responses to deviant stimuli.

We studied event-related potentials (ERPs) produced in response to deviant stimuli in a sequence of somatosensory stimuli which were measured under stimulus-ignoring conditions. A change in the repetitive somatosensory input elicited not only a frontal negativity which was similar to the somatosensory mismatch negativity very recently reported by Kekoni et al. [J. Kekoni, H. Hämäläinen, M. Saarinen, J. Gröhn, K. Reinikainen, A. Lehtokoski, R. Näätänen, Rate effect and mismatch responses in the somatosensory system: ERP-recordings in humans, Biol. Psychol. 46 (1997) 125-142] but also a positive deflection ranging in latency from 100 to 200 ms. This somatosensory change-related positivity was reduced with prolongation of the interstimulus interval (ISI) and was different from the responses to the deviant stimuli when they were presented alone. These findings suggest that the somatosensory change-related positivity is probably generated not by activation of new afferent elements but by a detection of change in a process of comparison with sensory memory.

Development of mechanisms regulating intracellular Ca2+ concentration in cardiac muscle cells of early chick embryos.

The development of mechanisms for the regulation of intracellular-free calcium ion concentration ([Ca2+]i) was investigated in precardiac mesodermal cells (PMC) and cardiac muscle cells (CMC) from early chick embryos by microfluorometry using a Ca2+-sensitive fluorescent probe, fura-2, and transmission electron microscopy. Microfluorometry indicated that two types of regulatory mechanisms, involving the dihydropyridine receptor (DHPR) and the ryanodine receptor (RYR), are present in CMC when the heartbeat begins at the 8-9 somite stages. Nifedipine completely suppressed the beating of hearts isolated from embryos on Days 1.5 and 2. Ryanodine had no effect on the beating of hearts isolated from embryos on Day 1.5, though it completely suppressed beating in hearts from Embryonic Day 2. Microfluorometry revealed that a change occurred in the Ca2+-regulating mechanisms of CMC on Day 2. Transmission electron microscopy showed the appearance in CMC, also on Day 2, of peripheral couplings with feet structures, and SR adjacent to the Z-line of myofibrils. These findings suggest that the calcium-induced calcium-release (CICR) mechanism appears in the CMC of the chick on the second day of embryonic development.

Formation of the ocular arteries in the chick embryo: observations of corrosion casts by scanning electron microscopy.

An investigation was carried out on the formation of the blood vessels that supply the optic cup or eyeball in developing chick embryos ranging in age from Hamburger-Hamilton stage 17 (st17) to st44. Corrosion casts of the vasculature were made by injecting resin and examined by scanning electron microscopy. The optic cup was supplied by branches of the cranial ramus of the circle of Willis (CCW) from st17 to st19. By st23, a branch of the CCW and that of the internal carotid artery became anlagen of two ophthalmic arteries, namely, the cerebral ophthalmic artery (COA) and the internal carotid ophthalmic artery (ICOA) respectively. They were continued by primordia of the long posterior ciliary arteries, which connected with each other to form a ring around the pupil. Between st19 and st26, another branch of the CCW was found, by contrast, to supply the primitive pecten. The distal part of the nasal long posterior ciliary artery began to atrophy at st28, so the temporal long posterior ciliary artery only began to supply the ring artery around the pupil by st30. At the same time, the artery supplying the pecten became anastomosed with the ICOA behind the eyeball to form the definitive pectinate artery. By st30, the ophthalmic branch of the stapedial artery had also formed and connected with the distal part of the ICOA behind the eyeball, as well as with the distal part of the COA by st34. The supraorbital branch of the stapedial artery, which had replaced the CCW to anastomose with the ethmoidal artery by st30, was found to be connected to the COA at st36. The main vascular system supplying the eyeball was complete at st36, and its structure at st40 and st44 was fundamentally similar to that at st36.

Hypoplasia of cushion ridges in the proximal outflow tract elicits formation of a right ventricle-to-aortic route in retinoic acid-induced complete transposition of the great arteries in the mouse: scanning electron microscopic observations of corrosion cast models.

BACKGROUND: The major morphologic change associated with retinoic acid (RA)-induced complete transposition of the great arteries (TGA), a congenital malformation of the heart, was investigated in a mouse model in which TGA was found in 80% of surviving fetuses. METHODS: Corrosion casts of embryonic hearts with or without prior exposure to retinoic acid were observed under a scanning electron microscope. RESULTS: In control hearts, indentations caused by expanded parietal and septal ridges in the outflow tract established right ventricle-to-left ventral pulmonic and left ventricle-to-right dorsal aortic routes before the aorticopulmonary septum completion. In RA-treated hearts, indentations of proximal regions of the parietal and septal ridges were small in the proximal outflow tract, whereas those in the distal regions developed well. These morphological features in the RA-treated hearts elicited right ventricle-to-right ventral aortic and left ventricle-to-left dorsal pulmonic routes in the TGA morphology. CONCLUSIONS: Hypoplasticity of the proximal regions of parietal and septal ridges in the outflow tract is one of the primary morphological abnormalities of the RA-induced TGA.

Inhibitory effect of cilnidipine on pressor response to acute cold stress in spontaneously hypertensive rats.

We investigated the effect of cilnidipine on cardiovascular and neuroendocrine responses to acute cold stress in conscious and unrestrained or moderately restrained spontaneously hypertensive rats (SHRs). Acute cold stress significantly increased mean blood pressure without marked change in heart rate. The acute cold stress-induced elevation in blood pressure was almost abolished by 1 mg/kg, p.o. of prazosin. The cold stress also elevated plasma norepinephrine and epinephrine levels. Cilnidipine at 3 mg/kg, p.o. significantly inhibited the pressor response to acute cold stress. Although 3 mg/kg, p.o. of nifedipine, nicardipine or manidipine lowered mean blood pressure to a similar extent as cilnidipine, none of these three drugs affected the pressor response. Cilnidipine also reduced the cold stress-induced increment in plasma norepinephrine but not the epinephrine level. These findings suggest that acute cold stress may induce the elevation in blood pressure due to an enhanced activation of the sympathoadrenal system in SHRs and that cilnidipine may suppress the pressor response by inhibiting the sympathetic nerve activity.

Inhibitory effect of cilnidipine on vascular sympathetic neurotransmission and subsequent vasoconstriction in spontaneously hypertensive rats.

We reported previously that cilnidipine inhibited increases in blood pressure and plasma norepinephrine (NE) level in response to cold stress in spontaneously hypertensive rats (SHRs). In the present study, we investigated the effect of cilnidipine on sympathetic neurotransmission and subsequent vasoconstriction in SHRs. In pithed SHRs, electrical sympathetic nerve stimulation (ESNS) elevated blood pressure, and this pressor response was abolished by guanethidine. Cilnidipine at 10 micrograms/kg, i.v. and phentolamine at 1 mg/kg, i.v. suppressed the pressor response to ESNS by 28 +/- 6% and 67 +/- 3%, respectively. Neither nifedipine nor nicardipine inhibited it. The pressor response to exogenous NE was not influenced by cilnidipine. alpha, beta-Methylene ATP inhibited the pressor response to ESNS in the presence or absence of phentolamine. Cilnidipine also attenuated the phentolamine-resistant pressor response to ESNS. In SHR mesenteric vasculatures preloaded with [3H]-NE, cilnidipine (10(-7) M) as well as omega-conotoxin significantly inhibited the 3H overflow evoked by periarterial nerve stimulation. In radioligand binding experiments, cilnidipine inhibited [125I]-omega-conotoxin binding to rat synaptosomes, but it did not inhibit [3H]-prazosin binding to rat cortex membranes. These results suggest that cilnidipine may reduce electrically stimulated NE release from the sympathetic nerve endings of SHR vasculatures probably through its N-type Ca channel blocking action and that cilnidipine may also inhibit the vasoconstriction induced by ATP released concomitantly during nerve stimulation.