Bunya Kuze

Morphology of single pontine reticulospinal axons in the lumbar enlargement of the cat: a study using the anterograde tracer PHA-L.

The fine morphology of single pontine reticulospinal axons in the lumbar enlargement was investigated by using an anterograde Phaseolus vulgaris–leucoagglutinin (PHA‐L) tracing technique. Localized injections of PHA‐L were made into the nuclei reticularis pontis oralis and caudalis in four cats. Following survival periods of 8–9 weeks, PHA‐L‐labeled axons were found throughout the lumbar enlargement from segments L4 to S2, in which the diameter of labeled axons was 0.6–2.5 μm. From serial transverse sections (50 μm), trajectories of 21 single pontine reticulospinal axons were traced in continuity over distances of 18.9–36.3 mm, corresponding to three to six segments, respectively. All the identified axons gave off multiple (two to nine) axon collaterals along their courses, with mean intercollateral distances of approximately 5–6 mm. Detailed reconstruction of the collateral arborization in the lumbar enlargement showed a high degree of similarity to that of single axons in the cervical enlargement previously reported (Matsuyama et al. [1997] J. Comp. Neurol. 377:234–250). First, axon collaterals arising from a majority (n = 18) of identified axons innervated the gray matter unilaterally, ipsilateral to the parent axons, whereas those from the remaining three axons innervated the gray matter bilaterally. Second, collateral projections terminated mainly in laminae VIII and VII, with the arborization field confined to a narrow rostrocaudal extent (<1 mm). Third, the termination fields of axon collaterals arising from a given reticulospinal axon were similar at each segmental level and differed from one stem axon to another. These results suggest that the long descending pontine reticulospinal pathway is composed of different types of axons that may innervate the cervical and lumbar enlargements in continuity in a similar manner. J. Comp. Neurol. 410:413–430, 1999.

Cerebellar-induced Locomotion: Reticulospinal Control of Spinal Rhythm Generating Mechanism in Catsa

Abstract: In a decerebrate cat (locomotor preparation), stimulation of a restricted region along the midline cerebellar white matter has been found to evoke generalized augmentation of postural muscle tone on a stationary surface (Asanome et al. 1998. Neurosci. Res. 30: 257‐269) and “controlled” locomotion on the surface of a moving treadmill. Characteristics of cerebellar‐evoked locomotion were similar to those of mesencephalic locomotor region‐evoked “controlled” locomotion on the same animal. Microinjection of a neural tracer (CTb‐HRP) into the lesioned stimulus site of the cerebellar white matter resulted in both retrograde labeling of cells in the fastigial nuclei, bilaterally, and anterograde labeling of fibers descending to the brain stem. These results indicated that the effective cerebellar stimulus site (cerebellar locomotor region) corresponded to the midline region of the hook bundle of Russell (Rasmussen, A. T., 1933. J. Comp. Neurol. 57: 165‐197), through which crossed fastigioreticular, fastigiovestibular, and fastigiospinal fibers pass. In this study, contribution of reticulospinal systems to the control of cerebellar‐evoked locomotion was extensively studied. By stimulating the cerebellar locomotor region and the MLR in the same animal, a majority of antidromically identified pontomedullary reticulospinal cells were synaptically activated. The results of the present study demonstrated that fastigial cells with crossed fastigioreticular fibers and reticulospinal fibers play a crucial role in the control of posture and locomotion in the locomotor preparation.

Dichloroacetate improves immune dysfunction caused by tumor-secreted lactic acid and increases antitumor immunoreactivity.

The activation of oncogenic signaling pathways induces the reprogramming of glucose metabolism in tumor cells and increases lactic acid secretion into the tumor microenvironment. This is a well‐known characteristic of tumor cells, termed the Warburg effect, and is a candidate target for antitumor therapy. Previous reports show that lactic acid secreted by tumor cells is a proinflammatory mediator that activates the IL‐23/IL‐17 pathway, thereby inducing inflammation, angiogenesis and tissue remodeling. Here, we show that lactic acid, or more specifically the acidification it causes, increases arginase I (ARG1) expression in macrophages to inhibit T‐cell proliferation and activation. Accordingly, we hypothesized that counteraction of the immune effects by lactic acid might suppress tumor development. We show that dichloroacetate (DCA), an inhibitor of pyruvate dehydrogenase kinases, targets macrophages to suppress activation of the IL‐23/IL‐17 pathway and the expression of ARG1 by lactic acid. Furthermore, lactic acid‐pretreated macrophages inhibited CD8+ T‐cell proliferation, but CD8+ T‐cell proliferation was restored when macrophages were pretreated with lactic acid and DCA. DCA treatment decreased ARG1 expression in tumor‐infiltrating immune cells and increased the number of IFN‐γ‐producing CD8+ T cells and NK cells in tumor‐bearing mouse spleen. Although DCA treatment alone did not suppress tumor growth, it increased antitumor immunotherapeutic activity of Poly(IC) in both CD8+ T cell‐ and NK cell‐sensitive tumor models. Therefore, DCA acts not only on tumor cells to suppress glycolysis but also on immune cells to improve the immune status modulated by lactic acid and to increase the effectiveness of antitumor immunotherapy.

Segment-specific branching patterns of single vestibulospinal tract axons arising from the lateral vestibular nucleus in the cat: A PHA-L tracing study

The purpose of the present study was to detail the spinal cord (SC) trajectories and arborization patterns of vestibulospinal axons descending from the lateral vestibular nucleus (LVN). An anterograde neural tracer, Phaseolus vulgaris‐leucoagglutinin (PHA‐L), was focally injected into the right‐side LVN in 8 cats. Their subsequent survival times varied from 4 days to 12 weeks. The labeled axons were found mainly in the brainstem after 4–5 days and in successively more caudal spinal segments after longer survival times: i.e., in C1–T2 after 2–3 weeks, in C3–T11 after 6–7 weeks, and in T7–S1 after 10–12 weeks. The trajectories of 28 single, thick (diameter ≥2.4 μm) lateral vestibulospinal tract (LVST) axons were traced from serial transverse sections of the SC from C1–8 (n = 10), T1–9 (n = 11), and T11–L7 (n = 7). In the cervical segments, the LVST axons gave off collateral fibers, which terminated mainly in Rexeds laminae VII–VIII. The terminal‐field patterns of these collaterals differed from one stem axon to another. In the thoracic segments, the terminal‐field patterns from a given LVST axon were similar at each segmental level, i.e., a few main branches with or without short side branches. At the L3–5 midlumbar level, the collaterals usually arborized more extensively, such that their terminal fields occupied a much greater region of laminae VII–VIII. In contrast, at the L6–7 lower lumbar level, collaterals arising from thin axons (diameter <1.0 μm) tended to innervate, with even more extensive arborization, the medial part of the lamina VIII. These results revealed common and segment‐specific collateral distribution patterns of LVST axons along the full extent of the spinal neuraxis. J. Comp. Neurol. 414:80–96, 1999.

The association of antidiuretic hormone levels with an attack of Meniere's disease

Objectives:  An elevation of the plasma antidiuretic hormone (ADH) levels has frequently been observed in Menieres disease patients. However, little is known regarding the mechanism behind such an elevation of ADH level in Menieres disease patients. Therefore, we measured the plasma ADH in Menieres disease patients and other vertigo patients to elucidate the association between the ADH levels, stress levels and the development of Menieres symptom.

Tracing Sox10-expressing cells elucidates the dynamic development of the mouse inner ear.

The inner ear is constituted by complicated cochlear and vestibular compartments, which are derived from the otic vesicle, an embryonic structure of ectodermal origin. Although the inner ear development has been analyzed using various techniques, the developmental events have not been fully elucidated because of the intricate structure. We previously developed a Sox10-IRES-Venus mouse designed to express green fluorescent protein under the control of the Sox10 promoter. In the present study, we showed that the Sox10-IRES-Venus mouse enabled the non-destructive visualization and understanding of the morphogenesis during the development of the inner ear. The expression of the transcription factor Sox10 was first observed in the invaginating otic placodal epithelium, and continued to be expressed in the mature inner ear epithelium except for the hair cells and mesenchymal cells. We found that Sox10 was expressed in immature hair cells in the developing inner ear, suggesting that hair cells were generated from the Sox10-expressing prosensory cells. Furthermore, we demonstrated that scattered Sox10-expressing cells existed around the developing inner ear, some of which differentiated into pigmented melanocytes in the stria vascularis, suggesting that they were neural crest cells. Further analyzing the Sox10-IRES-Venus mice would provide important information to better understand the development of the inner ear.

A characteristic pattern in the postural sway of unilateral vestibular impaired patients.

The statistical properties of the center of pressure (COP) change over time, and -invariant methods of the COP analysis is not sufficient to monitor the changes. Therefore, dynamic temporal information of the COP signals has been important in assessing the postural stability. The purpose of this study was to evaluate the characteristic pattern of time-frequency dynamics during the upright stance in patients with unilateral vestibular dysfunction (UVD). This study included 20 dizzy patients with UVD and age-matched 20 control subjects without any vestibular disorder. The COP signals were collected using a single standard force platform and a spectral analysis including the time-frequency dynamics was carried out on the basis of the maximum entropy method (MEM) by using a segment time series analysis. The power spectral density (PSD) analysis exhibited an exponential decreasing shape (1/f (-)(β)) when plotted on a double logarithmic scale. The average value of β in the low frequency range of less than 1 Hz in the UVD group was significantly lower than that in the control group (p < 0.05) in the medial-lateral (ML) direction under eyes closed condition. In the segment time series analysis, the peak frequency of the COP signals in the patients with UVD gradually converged to the frequency range of 0.1-0.2 Hz in the ML direction under EC condition. Our results suggest that the segment time series analysis of the COP signals can derive a characteristic pattern related to the UVD. It may indicate an increased reflexivity of the COP fluctuation by the UVD, resulting in inducing the instability.

Mucosa-associated lymphoid tissue lymphoma of the salivary glands: MR imaging findings including diffusion-weighted imaging

PURPOSE The purpose of this study was to describe MR findings including diffusion-weighted (DW) imaging findings in patients with mucosa-associated lymphoid tissue (MALT) lymphoma of the salivary glands. MATERIALS AND METHODS Ten patients with histologically proven MALT lymphoma of the salivary glands were included. All patients underwent 1.5-T MR imaging, six of the ten underwent DW imaging, nine underwent CT, and eight (18)F-fluorodeoxyglucose (FDG) PET/CT. MR images were reviewed for numbers, locations, sizes, MR imaging characteristics, and apparent diffusion coefficients (ADCs). Calcium deposition and maximum standardized uptake values (SUVmax) were also assessed. RESULTS Twenty-six tumors, ranging in number from 1 to 5 (mean, 2.6), were identified. Nine patients had tumors in the parotid glands and one in the submandibular glands. Tumors were found bilaterally in 7 patients and unilaterally in three. Tumors ranged in size from 0.6 to 5.5cm (mean, 1.8cm). Ten (38%) tumors had intratumoral cystic formations and 8 (31%) had ill-demarcated margins. DW images showed hyperintensity with extremely low ADCs (range, 0.48-0.82 [×10(-3)mm(2)/s]; mean, 0.64) for solid components of all 19 tumors in the 6 examined patients. Calcium deposition was found in one (4%) tumor on CT. SUVmax variously ranged from 1.3 to 17.7 (mean, 6.3). CONCLUSION Salivary gland MALT lymphomas were often found bilaterally and were occasionally accompanied by intratumoral cystic formations and ill-demarcated margins. DW imaging may play a supplementary role in the diagnosis of lymphoma, because it showed restricted water molecule diffusion, whereas PET/CT showed indeterminate findings.

Disorder of the saliva melatonin circadian rhythm in patients with Meniere's disease

Objectives –  Stress is involved in the development of symptoms of Menieres disease (MD). Stress‐related disease has been reported to be associated with disorders in the circadian rhythm of melatonin (MEL) which regulates that rhythm. We therefore investigated MEL circadian rhythm of patients with MD.

M2-like macrophage polarization in high lactic acid-producing head and neck cancer.

Reprogramming of glucose metabolism in tumor cells is referred to as the Warburg effect and results in increased lactic acid secretion into the tumor microenvironment. We have previously shown that lactic acid has important roles as a pro‐inflammatory and immunosuppressive mediator and promotes tumor progression. In this study, we examined the relationship between the lactic acid concentration and expression of LDHA and GLUT1, which are related to the Warburg effect, in human head and neck squamous cell carcinoma (HNSCC). Tumors expressing lower levels of LDHA and GLUT1 had a higher concentration of lactic acid than those with higher LDHA and GLUT1 expression. Lactic acid also suppressed the expression of LDHA and GLUT1 in vitro. We previously reported that lactic acid enhances expression of an M2 macrophage marker, ARG1, in murine macrophages. Therefore, we investigated the relationship between the lactic acid concentration and polarization of M2 macrophages in HNSCC by measuring the expression of M2 macrophage markers, CSF1R and CD163, normalized using a pan‐macrophage marker, CD68. Tumors with lower levels of CD68 showed a higher concentration of lactic acid, whereas those with higher levels of CSF1R showed a significantly higher concentration of lactic acid. A similar tendency was observed for CD163. These results suggest that tumor‐secreted lactic acid is linked to the reduction of macrophages in tumors and promotes induction of M2‐like macrophage polarization in human HNSCC.