Fate redirection of hippocampal astrocytes toward neuronal lineage by aggregate culture

Mammalian cells that have been committed to a certain cell lineage cannot be directed to other lineages. However, some astrocytes in the mammalian brains have been reported to represent plasticity to redirect to other cell lineages. We found that mouse hippocampal astrocytes cultured in aggregate forms of "astrosphere", redirected to MAP2-positive immature neurons. In astrospheres, basic HLH factors positively regulating neuronal differentiation were up-regulated and Id3 inhibiting basic HLH factors was down-regulated. Ectopic Id3 induction repressed redirection of astrocytes to a neuronal lineage, suggesting that astrosphere formation induced plasticity of astrocytes by changing the gene expression patterns.     

Ultrastructural and biochemical studies on the intestinal absorption of a medium-chain triglyceride (MCT), tricaprylin

The intestinal absorption of a medium-chain triglyceride (MCT) was studied by electron microscopy and biochemical analysis. In jejunal absorptive cells of rats fed tricaprylin, the smooth endoplasmic reticulum in the apical cytoplasm appeared to increase in number and contained one or two particles about 40–80 nm in diameter that were less electron dense and similar in size and profile to very low density lipoprotein. Similar particles were also observed packed in the dilated Golgi sacs and in the extended intercellular spaces. These particles were remarkably increased in number as compared with those in fasted rats. Biochemical analysis of lymph from the main intestinal lymph duct showed that caprylate was apparently demonstrated only in the lymph of rats given tricaprylin at the maximum rate 3h after oral administration. The study strongly suggests that medium-chain triglyceride is at least in part transported via lacteal, possibly in the form of very low density lipoprotein.     

Loss of the SEDL gene product (Sedlin) causes X‐linked spondyloepiphyseal dysplasia tarda: Identification of a molecular defect in a Japanese family

A 23‐year‐old man was diagnosed as having X‐linked spondyloepiphyseal dysplasia tarda (SEDT; MIM 313400) based on his disproportionately short trunk, short stature, characteristic radiological features of the spine (posterior hump, end plate sclerosis, and disc space narrowing) and the hips (short and thick femoral necks), and positive family history. This Japanese family was found to have an intragenic deletion flanking intron 2 and exon 3 of the SEDL gene that not only included the 5′ untranslated region but also the coding sequence for the first methionine through the 25th alanine. This mutation was present in the proband and his unaffected mother (a heterozygote), but not in an unaffected sister and an unaffected uncle. The nature of the mutation predicted that the SEDL protein (Sedlin) was not produced in the proband, indicating that loss of Sedlin caused SEDT. © 2001 Wiley‐Liss, Inc.     

Human marrow cells-derived cultured bone in porous ceramics

From four patients (mean age, 60 years; range 51-76 years), 3 ml of bone marrow was collected from the ilium. The marrow was cultured to concentrate and expand the marrow mesenchymal cells on a culture dish. The cultured cells were then subcultured either on another culture dish or in porous areas of hydroxyapatite ceramics in the presence of dexamethasone and beta-glycerophosphate (osteogenic medium). The subcultured tissues on the dishes were analyzed by scanning electron microscopy (SEM), and subcultured tissues in the ceramics were implanted intraperitoneally into athymic nude mice. Vigorous growth of spindle-shaped cells and a marked formation of bone matrix beneath the cell layers was observed on the subculture dishes by SEM. The intraperitoneally implanted ceramics with cultured tissues revealed thick layer of lamellar bone together with active osteoblasts lining in many pore areas of the ceramics after 2 months. The in vitro bone formation on the culture dishes and in vivo bone formation in porous ceramics were detected in all cases. These results indicate that we can assemble an in vitro bone/ceramic construct, and due to the porous framework of the ceramic, the construct has osteogenic potential similar to that of autologous cancellous bone. A significant benefit of this method is that the construct can be made with only a small amount of aspirated marrow cells from aged patients with little host morbidity.     

Adaptive Predictive Control of Arterial Blood Pressure Based on a Neural Network During Acute Hypotension

In acute hypotension, an automated drug infusion system to control mean arterial blood pressure (MAP) has not been previously studied, though many investigations have examined the use of vasodilating drugs to control MAP in postoperative hypertension. Therefore, we examined an automated control of MAP during acute hypotension using a neural network (NN) approach. A proportional-integral-derivative (PID) control, an adaptive predictive control using a NN (APC(NN)), a combined control of APC(NN) and PID (APC(NN-PID)), a fuzzy control, and a model predictive control were tested in computer simulation based on the MAP response to norepinephrine (NE) of 25 microg ml(-1). In six anesthetized rabbits, using the NE of 25 microg ml(-1), the PID control, APC(NN), and APC(NN-PID) prevented severe hypotension compared to an uncontrolled condition. Under PID control, four of the six animals showed MAP oscillation. Using NE of 50 microg ml(-1), the rabbits recovered from acute hypotension for all systems tested but showed sustained MAP oscillation during PID control. In conclusion, utilization of a NN for adaptive predictive control systems could facilitate the development of an automated drug infusion apparatus because it provides robust control even when acute or large perturbations and inter-individual differences in the sensitivity to therapeutic agents occur.     

Localization of motoneurons innervating the posterior belly of the digastric muscle: a comparative anatomical study by the HRP method.

Motoneurons innervating the posterior belly of the digastric muscle were identified in the monkey, cat, dog, guinea pig and rat by the HRP method. After injections of horseradish peroxidase (HRP) into the posterior belly of the digastric muscle, two groups of HRP-labeled motoneurons were observed; the rostral group was seen as a small cluster of neurons in the lateral reticular area along the medial border of the descending root of the facial nerve, and the neurons of the caudal group were distributed among the ascending root fibers of the facial nerve. The distribution pattern of these neurons corresponded to that of the accessory facial nucleus neurons. The accessory facial nucleus was lacking in the rabbit in which the posterior digastric (PD) muscle is nonexistent.