Spatial distribution of evoked potentials in the inferior olivary nucleus by stimulation of the visual afferents in the rat

Visual pathways (optic disc, optic nerve and pretectal regions) were electrically stimulated and evoked potentials were explored throughout the inferior olive in the anesthetized rat. Responsive areas were identified as the caudal half of the dorsal cap, nucleus beta and the most caudal region of subnucleus c of the medial accessory olive. No field potentials were identified in the rostral half of the dorsal cap, its ventrolateral outgrowth or the dorsomedial cell column. Contralateral retinal afferents were only effective all over the responsive areas.     

Efficiency-optimized speed control system in separately excited DC-motor drives—performance index method

This paper proposes a synthesis method for an efficiency-optimized speed control system using a performance index including loss term. Since the performance index almost includes the loss term at the steady state, suboptimal efficiency is obtained. The speed response is controlled by tuning the values of the weighting factors at the transient state. The effectiveness is shown in simulation and experimental studies, and the system is more efficient than the usual control systems with constant field excitation.     

Immunohistochemically demonstrated altered expression of cytochrome P-450 molecular forms and epoxide hydrolase in N-ethyl-N-hydroxyethylnitrosamine-induced rat kidney and liver lesions

A comparison of N-ethyl-N-hydroxyethylnistrosamine (EHEN)-inducedpreneoplastic and neoplastic lesions in the rat liver and kidneywas made with respect to the expression of different drug metabolizingenzymes. Four cytochrome P-450 species (cyt. P-450 UT₅₀, PB_3a,MC₁ and MC₂) and microsomal epoxide hydrolase (mEHb) were investigatedalong with two glutathione S-transferase species (GST-P andA forms) earlier shown to be elevated in putative preneoplasticlesions in the liver and kidney, respectively. In contrast tothe liver lesions, which showed clear decrease in all formsof cyt. P-450s and increase of mEHb, elevated levels of cyt.P-450 PB_3a and, to a lesser extent, the other P-450 forms andearly elevation to late decrease in mEHb characterized the renaltubular lesions. Thus opposite shift in enzyme phenotype wasobserved in carcinogen-induced focal lesions of the two organs.Variation in binding levels in the different nephron segmentsand zones of the liver acinus indicated physiological specializationwith regard to the enzymes investigated and suggested that thealtered phenotype of preneoplastic populations might be of adaptivesignificance.     

Spermatozoon and mitochondrial DNA

In eukaryotic cells, mitochondria are the major site of ATP production, which is achieved through the electron-transport chain and oxidative phosphorylation, according to the energy demand. Mitochondria contain their own genome (mitochondrial DNA, mtDNA) on which a limited number of genes are encoded. In the human sperm, mitochondria helically wrap the midpiece of the tail and supply the energy for the driving force of motility. While various mutations in mtDNA in somatic cells are found to be associated with a wide spectrum of diseases, it is also reported that the abnormal mtDNA causes astenozoospermia and male infertility. At fertilization, the paternal mitochondria and mtDNA are rapidly degraded early in embryogenesis, thus, only maternal mtDNA is transmitted to the descendant. We briefly review here the basic characteristics of mtDNA and its maternal transmission during fertilization, as well as male infertility. (Reprod Med Biol 2002; 1 : 41–47)     

Water/Ethanol Selectivity of New Organic‐Inorganic Hybrid Membranes Fabricated from Poly(vinyl alcohol) and an Oligosilane

To control the swelling of PVA membranes, mixtures of PVA and an inorganic oligosilane were prepared using sol‐gel reactions to yield new PVA/oligosilane hybrid membranes. In the separation of an ethanol/water azeotropic mixture during pervaporation, the effect of the oligosilane content on the water/ethanol selectivity of PVA/oligosilane hybrid membranes was investigated. The water/ethanol selectivity of PVA/oligosilane hybrid membranes was higher than that of PVA membranes, but the water/ethanol selectivity of hybrid membranes decreased with increasing oligosilane content. In order to increase the water/ethanol selectivity, PVA/oligosilane hybrid membranes were annealed. The water/ethanol selectivity of annealed PVA/oligosilane hybrid membranes was greater than un‐annealed hybrid membranes, and significantly governed by the oligosilane content, which could be attributed to both sorption and diffusion selectivities. The relationship between the structure of un‐annealed and annealed PVA/oligosilane hybrid membranes along with permeation and separation characteristics of an ethanol/water azeotropic mixture during pervaporation are discussed in detail.

     

Crosstalk between high-molecular-weight adiponectin and T-cadherin during liver fibrosis development in rats

Adiponectin, a circulating adipocyte-derived secretory protein, reportedly plays an important role in liver fibrosis development, although the biological role of adiponectin in liver fibrogenesis is still controversial. Adiponectin is present in the serum as three oligometric complexes; namely, high-, middle-, and low-molecular weight (HMW, MMW, and LMW, respectively). Adiponectin exerts different biological activities in an oligomerization-dependent manner. The aim of our current study was to examine the alteration of each isoform of adiponectin and its receptors (AdipoR1, AdipoR2, and T-cadherin) during the choline-deficient L-amino acid-defined (CDAA) diet-induced rat liver fibrosis development. We also elucidated the methylation status of all receptors. The serum level of total adiponectin significantly increased during the liver fibrosis development. Among the three isoforms, only HMW adiponectin was significantly up-regulated whereas MMW and LMW were not. The expression of T-cadherin, which exclusively binds with HMW adiponectin, was significantly augmented as well. The AdipoR2 expression was markedly decreased and showed no marked difference from that of AdipoR1. No obvious methylation change was observed in all three receptors, suggesting that another mechanism is involved in the alteration of receptor gene expression. Collectively, since the specific ligand and receptor were augmented together, crosstalk between HMW adiponectin and T-cadherin may play an important role during liver fibrosis development in rats.     

Langerhans cell histiocytosis of the skull on cytologic squash preparations

We present a case in which a primary cytodiagnosis of Langerhans cell histiocytosis (LCH) of the skull was made using squash preparations. The patient, a 25-year-old male, presented with raised intracranial pressure and decreased visual acuity. Magnetic resonance imaging revealed a large skull lesion with osteolytic features in the left frontal bone. The patient underwent surgical resection by the extended basal frontal epidural approach. The squash preparation smears were cellular and demonstrated a mixed population of small, mature lymphocytes, eosinophils, and a high histiocytes content. The histiocytes occurred as isolated or loosely cohesive and clustered. They possessed abundant cytoplasm with rounded cell shape and had characteristic nuclear features, composed of fine chromatin and delicate nuclear membranes. The cytologic features of these histiocytes were consistent with Langerhans cells (LCs). A final impression of LCH of the skull was rendered. Subsequent histopathology confirmed the diagnosis. LCs reacted with both S-100 protein and CD1a immunohistochemically. The demonstration of Birbeck granules on electron microscopic study was also noted. Whenever squash preparation yields a mixed population of mature lymphocytes, eosinophils, and histiocytes, the cytologists should be aware of and consider LCH as a diagnostic possibility.