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Biomedical subjects

A Shimada

Publications and source records attributed to A Shimada.

At least 109 records · Page 6Linked to original sources

Amyotrophic lateral sclerosis in an adult following acute paralytic poliomyelitis in early childhood.

About 30% of polio survivors develop a post-polio syndrome. Some of these patients develop slowly progressive muscle weakness known as post-poliomyelitis muscular atrophy (PPMA). We describe an unusual form of amyotrophic lateral sclerosis (ALS) in a patient with acute poliomyelitis in childhood. An 80-year-old woman had acute poliomyelitis at 2 years of age and developed weakness limited to the lower extremities. Residual weakness was stable until the age of 75 when she developed rapidly progressive weakness that first affected her left arm and subsequently the right arm. Neurological examination revealed both upper and lower motor neuron signs. These clinical features were more consistent with ALS than PPMA. At autopsy, there was marked atrophy of the precentral gyrus. Microscopic examination revealed a severe loss of all nerve cells and pronounced fibrillary astrocytosis of the lumbar ventral horns in the spinal cord, presumably a result of poliomyelitis. Superimposed on these spinal cord alterations were the pathological features of ALS, consisting of loss of Betz cells, corticospinal tract degeneration and loss of motor neurons of other levels of the spinal cord. The findings included some atypical features for ALS, namely, sparing of the hypoglossal nucleus, absence of Bunina bodies and absence of ubiquitin-immunoreactive inclusions. Although poliomyelitis and ALS may be coincidental, the unusual pathological expression of ALS raise the possibility that it is related to the antecedent poliomyelitis.

Aged↗

Pulmonary toxicity caused by acute exposure to mercury vapor is enhanced in metallothionein-null mice.

This study examined the protective role of metallothionein (MT) against pulmonary damage caused by acute exposure to metallic mercury (Hg0) vapor using MT-null and wild-type mice. Both strains of mice were exposed to Hg0 at 6.6 to 7.5 mg/m3 for 4 hr each day for 3 consecutive days. This dosing protocol was lethal to over 60% of MT-null mice but did not kill any wild-type mice. More severe pulmonary damage was found by histopathological observation in MT-null mice than in wild-type mice. MT levels in the lung were elevated in wild-type mice after Hg0 vapor exposure, and gel filtration of the lung cytosol revealed that most of the mercury was associated with MT. In MT-null mice, MT levels were below the limit of detection (0.2 microg/g tissue) for the MT assay even after exposure. After exposure to Hg0 vapor for 3 consecutive days, the pulmonary mercury levels in wild-type mice were significantly higher than in MT-null mice. These findings suggest that MT plays a protective role against the acute pulmonary toxicity of Hg0 vapor.

Administration, Inhalation↗

Effects of troglitazone on fat distribution in the treatment of male type 2 diabetes.

We investigated the efficacy of additional administration of 400 mg troglitazone (+T), which became available as a treatment for type 2 diabetes following the demonstration of its ability to reduce insulin resistance, in combination with diet (D + T) or sulfonylurea (S + T) therapy. Body fat area as determined by computed tomographic (CT) scanning at the umbilical level, as well as several clinical and biochemical parameters of glycemic control and lipid metabolism, were compared before and after 3 months of additional treatment with troglitazone. The body mass index (BMI) tended to increase in both groups (22.7 +/- 0.6 v 23.2 +/- 0.6 kg/m2 in D + T, nonsignificant [NS]; 22.2 +/- 0.5 v 22.3 +/- 0.5 kg/m2 in S + T, NS), while it tended to decrease in the control group (only diet therapy, 23.6 +/- 0.6 v 23.1 +/- 0.8 kg/m2, NS). Mean blood pressure ([BP] 96 +/- 3 v 89 +/- 4 mm Hg, P < .05) decreased significantly in the D + T group. Changes in the glycemic and lipid profile and leptin did not reach statistical significance. The D + T group showed a significant decline in immunoreactive insulin ([IRI] 12.4 +/- 1.2 v 8.0 +/- 1.0 microU/mL, P < .05), reflecting markedly reduced insulin resistance, as well as a significant increase in plasma insulin-like growth factor-1 ([IGF-1] 175.7 +/- 14.2 v 189.8 +/- 12.6 ng/mL, P < .05). A slight weight gain was associated with a tendency for subcutaneous fat to increase, while visceral fat decreased in both troglitazone-treated groups. The decrease in the visceral to subcutaneous fat ratio (V/S ratio) was statistically significant in the D + T group (1.09 +/- 0.11 v 0.94 +/- 0.09, P < .05), while the V/S ratio in the control group did not change. A notable finding of this study is the difference in the response to troglitazone between subcutaneous and visceral adipose tissue. It is suggested that troglitazone may exert beneficial effects by reducing visceral fat.

Adipose Tissue↗

Methyl alpha-D-mannopyranoside-responsive release of microencapsulated glucoamylase.

Microcapsules are made of porous membranes through which enzymes or proteins can readily permeate. Glucoamylase was encapsulated into microcapsules in the presence of concanavalin A. Microencapsulated glucoamylase was released from the microcapsules into the bulk phase in the presence of methyl alpha-D-mannopyranoside, while it was not released in the absence of methyl alpha-D-mannopyranoside. The initiation and cessation of glucoamylase release from the microcapsules accurately corresponded to the addition and removal of methyl alpha-D-mannopyranoside, respectively. Methyl alpha-D-mannopyranoside served as a controller for the release of glucoamylase.

Journal Article↗

Inactivation of p34cdc2 kinase by the accumulation of its phosphorylated forms in porcine oocytes matured and aged in vitro.

Culturing of matured porcine oocytes in vitro results in the enhancement of their cytoplasmic ability for oocyte activation (so-called ageing), although they are arrested at metaphase II. The enhanced ability for oocyte activation is related to decreased activity of the maturation promoting factor (MPF). In the present study we clarified the molecular mechanism of MPF inactivation during ageing, especially the changes in the phosphorylation status of p34cdc2, a catalytic subunit of MPF, compared with that in fertilised oocytes. The MPF activity decreased gradually when maturation culture was prolonged from 36 to 72 h, confirming the decreasing MPF activity in aged oocytes. The activity of 48 h matured oocytes also decreased after in vitro fertilisation. Immunoblotting of p34cdc2 with anti-PSTAIRE antibody revealed that the culturing of matured oocytes induces a gradual increase in pre-MPF, which is a p34cdc2 and cyclin B complex inactivated by phosphorylation at the inhibitory phosphorylation site of p34cdc2. In contrast, pre-MPF decreased after fertilisation, indicating the degradation of cyclin B. These results suggest that the molecular mechanisms of inactivation of MPF are different between oocyte activation and ageing, and that the mechanism during ageing might be based on the inhibitory phosphorylation of p34cdc2, whereas that of oocyte activation is based on the degradation of cyclin B.

Amino Acid Sequence↗

Direct evidence for in vivo reversible tyrosine phosphorylation of the N-terminal domain of the H/K-ATPase alpha-subunit in mammalian stomach cells.

In vivo reversible phosphorylation of Tyr-7 and Tyr-10 of the pig stomach H/K-ATPase alpha-chain was initially demonstrated in mammals, rat, rabbit, and pig, in the presence of vanadate + H(2)O(2). In vitro phosphorylation has also been unequivocally demonstrated via the use of protease inhibitors during membrane H/K-ATPase preparation. An amphoretic detergent permitted each intrinsic kinase to phosphorylate each fusion protein containing the requisite Tyr residues, along with a reduction in alpha-chain phosphorylation. These and other data suggest that some important enzyme systems are present in the apical membrane and that they are in sufficient proximity to participate in the reversible phosphorylation of the amino terminal soluble domain of the alpha-chain with an unknown physiological function in the membrane embedded H/K-ATPase.

Animals↗

Developmental competence, after transfer to recipients, of porcine oocytes matured, fertilized, and cultured in vitro.

The objective of this study was to evaluate the developmental ability of early porcine embryos produced in vitro and transferred to recipient gilts. Porcine cumulus-oocyte complexes were matured in modified North Carolina State University-37 solution for 44-46 h (in vitro maturation, IVM). In vitro fertilization (IVF) was performed with frozen-thawed epididymal spermatozoa. Inseminated oocytes were cultured in vitro (IVC) for 0, 24, or 48 h in modified NCSU-37 solution. Embryos were surgically transferred to the oviducts of recipients in which estrus had been synchronized with eCG and hCG. On the 29th day post-IVF, the uteri of some recipients were surgically examined for pregnancy; then pregnant females were hysterectomized in order to examine number and weight of the fetuses. Developmental rates to fetuses for IVM/IVF oocytes cultured for 24 and 48 h were significantly lower (p < 0.05, 1.7% and 2.0%, respectively) than that of IVM/IVF oocytes without IVC (6.7%). However, the weights of fetuses (1.0-1.2 g) did not differ among the experimental groups. The other recipients were examined for pregnancy using an ultrasound pregnancy detector, and pregnant females were allowed to go to term. Healthy piglets were delivered by some recipients to which embryos cultured for 0 or 24 h had been transferred; however, no farrow was obtained from embryos cultured for 48 h before the transfer. The results indicate that the viability of in vitro-produced porcine embryos is decreased by IVC after IVF; however, these embryos have competence to develop to term. An improved IVC system of porcine IVM/IVF oocytes is needed to generate advances in this field.

Animals↗

Efficacy of endoscopic static pressure/area assessment of the passive pharynx in predicting uvulopalatopharyngoplasty outcomes.

OBJECTIVES/HYPOTHESIS: Although uvulopalatopharyngoplasty (UPPP) is an attractive surgical treatment for obstructive sleep apnea (OSA), the unpredictable outcome limits application of the procedure. Since UPPP corrects only retropalatal airway (RP) patency, we hypothesized that response to UPPP is determined by collapsibility of the retroglossal airway (RG), where UPPP does not correct. METHODS: We estimated closing pressure (Pclose) for each pharyngeal segment by endoscopically obtaining the static pressure/area relationship of the passive pharynx in completely paralyzed and anesthetized patients with sleep-disordered breathing (n = 41) before UPPP. Preferable response to UPPP was defined as the number of oxygen dips (ODI), obtained by nocturnal oximetry, less than 10 h(-1) after UPPP. RESULTS: Patients with negative Pclose at RG responded to UPPP significantly better than those with positive Pclose at RG (22/30 [73%] vs. 3/11 [27%], P<.05). ODI after UPPP was significantly correlated with age, Pclose at RP, and Pclose at RG. CONCLUSIONS: Endoscopic assessment of anatomic abnormality of the pharynx in paralyzed patients with sleep-disordered breathing under general anesthesia has clinical value for the improvement of UPPP outcome.

Adult↗

Oligodendroglial vacuolar degeneration in the bilateral motor cortices and astrocytosis in epileptic beagle dogs.

We performed a pathologic examination of the brains of three dogs in an epileptic beagle colony. Histologically, all the cases had diffuse astrocytosis in the cerebral cortex and basal ganglia as well as the hippocampus, whereas they showed acute nerve cell change in the hippocampus and some other areas of the cerebrum. One of these animals showed laminar myelin pallor associated with the presence of many vacuoles in the IV to VI layers of the bilateral motor cortices. Most of the vacuoles contained fine granules stained with luxol-fast-blue stain. Ultrastructural examination revealed that some oligodendrocytes and perineuronal satellite oligodendrocytes in the bilateral cerebral motor cortices of the two affected dogs had many vacuoles surrounded by myelin-like lamellar structures. These findings suggest a possibility that astrocytosis in the cerebrum and vacuolar degeneration of oligodendrocytes in the cerebral motor cortex may be, at least in part, related to the occurrence or development of seizures.

Animals↗

Localization of metallothioneins-I & -II and -III in the brain of aged dog.

Localization of metallothionein (MT) -I & -II and MT-III and its significance in the brain aging in dogs were examined using immunohistological and molecular pathological techniques. MT-I & -II immunohistochemistry showed positive staining in the hypertrophic astrocytes throughout the aged dog brains; these MT-I & -II immunoreactive astrocytes were predominant in the cerebral cortex and around the blood vessels in the brain. These findings dominated in the brain regions with severe age-related morphological changes. In situ hybridization using MT-I mRNA riboprobes also demonstrated signals for MT-I mRNA in these hypertrophic astrocytes. Immunohistochemistry using a guinea pig antiserum against a synthetic polypeptide of canine MT-III demonstrated positive MT-III immunoreactivity predominantly in neurons in the Zn-rich regions such as hippocampus and parahippocampus. The findings were supported by in situ hybridization using MT-III mRNA riboprobes. Both MT-III immunoreactivity and signals for MT-III mRNA were demonstrated in neurons in the brain regardless of the intensity of the age-related changes. These results suggest, first, MT-I & -II may be induced in relation to the progress of the age-related morphological changes in the brain, playing an important role in the protection of the brain tissue from the toxic insults responsible for the brain aging, and second, MT-III may play a role in maintenance of Zn-related essential functions of the brain.

Aging↗

Intranasally inoculated Mycoplasma hyorhinis causes eustachitis in pigs.

Specific-pathogen-free pigs were experimentally inoculated with Mycoplasma hyorhinis, Pasteurella multocida, or both bacterial isolates to evaluate the role of these bacteria in the pathogenesis of otitis media. Six pigs were inoculated intranasally with 4.4 X 10(8) colony-forming units (CFU) of M. hyorhinis. Twenty-one days later, three of these six pigs were inoculated intranasally with 5.0 X 10(8) CFU of P. multocida. Three additional pigs were also inoculated intranasally at the time with P. multocida alone. Two pigs served as uninoculated controls. Seven days later, all pigs were euthanatized. Histologically, subacute inflammation was found in 10 auditory tubes of six pigs and two tympanic cavities of two pigs inoculated with M. hyorhinis. Immunohistochemically, M. hyorhinis antigens were detected on the luminal surface of eight of 10 inflamed auditory tubes, and ultrastructural examination confirmed mycoplasmal organisms in two pigs. M. hyorhinis was isolated from the inflamed tympanic cavities of two pigs. None of the pigs inoculated only with P. multocida had otitis, and P. multocida was not isolated from the tympanic cavity. These findings indicate that M. hyorhinis can cause eustachitis but rarely otitis media in specific-pathogen-free pigs.

Administration, Intranasal↗

T-cell insulitis found in anti-GAD65+ diabetes with residual beta-cell function. A case report.

CASE HISTORY: We recently encountered a 65-year-old anti-GAD+ diabetic woman with residual beta-cell function who was proved to have T-cell insulitis. The proportion of CD4+ and CD8+ cells varied among individual islets, although CD4+ cells tended to be the predominant T-cell type in the islets examined. All of the islets examined still contained insulin, suggesting that beta-cell mass may have been preserved. DISCUSSION: It is well known that lymphocytic infiltration of pancreatic islets, a condition referred to as "insulitis," is seen in acute-onset type 1 diabetes at autopsy and in biopsy specimens. However, there have been no proven cases of insulitis in type 1 diabetes with residual beta-cell function. We believe that this is the first type 1 diabetic patient with residual beta-cell function who was proven to have T-cell insulitis. This novel evidence will contribute to the proper classification and treatment of diabetes and to a better understanding of the pathophysiology of type 1 diabetes.

Aged↗

[A case of medial medullary infarction without Dejerine syndrome].

A 67-year-old man with right hemiparesis and dysarthria was admitted with right hemiparesis involving the face, hyperpathia, numbness and pain of the right body and limb except the face, and had hyperreflexia and pathological reflex in the right limb. Brain MRI on the day after admission disclosed no lesion which might explain the symptoms. Short latency somatosensory evoked potential showed a low amplitude after P14 when the right side was stimulated. Cerebral angiography revealed occlusion of the left vertebral artery. Brain MRI on the 18th hospital day disclosed left medial medullary infarction, so we diagnosed medial medullary syndrome. This case was hard to diagnose, because of the atypical features and the absence of an abnormal lesion on the initial MRI.

Aged↗

Structure-activity relationship of hydroxamate-based inhibitors on membrane-bound Fas ligand and TNF-alpha processing.

Both Fas ligand (FasL) and tumor necrosis factor-alpha (TNF-alpha) are type II integral membrane proteins. Recently, we have reported that FasL is processed to a soluble form by an unknown metalloproteinase at the cell surface and some hydroxamate matrix metalloproteinase (MMP) inhibitors inhibit the processing similar to the case observed with TNF-1alpha. We studied the inhibitory effects of various hydroxamate MMP inhibitors on FasL and TNF-alpha processing in order to characterize the processing enzymes using human FasL cDNA transfectants and LPS-stimulated THP-1 cells. It turned out that (1) the P1' group of hydroxamates was very important for the selective inhibitory activity toward TNF-alpha and FasL processing, (2) P1' 3-phenylpropyl group was favorable for the inhibition of FasL processing, and (3) P1' isobutyl and isopropyl groups were favorable for that of TNF-alpha processing. These differences in sensitivity to inhibitors imply that (1) membrane-bound FasL and TNF-alpha might be processed by distinct metalloproteinases, (2) the S1' site of FasL processing enzyme differs from that of MMP-1 and MMP-9, but appears to be similar to that of MMP-3, and (3) the S1' site of TNF-alpha processing enzyme is smaller than that of FasL processing enzyme. These results would be helpful in designing a more selective inhibitor.

Humans↗

Molecular detection of heparan sulfate proteoglycan mRNA in rat kidney during calcium oxalate nephrolithiasis.

The present study used reverse transcription (RT)-PCR to examine heparan sulfate proteoglycan (HSPG) mRNA expression in rat kidneys. Total mRNA in kidney was isolated and converted to cDNA. To confirm the exact expression level of HSPG mRNA, quantitative competitive (QC)-PCR was performed for each sample. PCR products were resolved by electrophoresis on 1.5% agarose gel and visualized with ethidium bromide. Fragment intensity and area were measured using an image analyzer. In QC-PCR, target DNA and competitive DNA were expressed, using gene-specific primer for HSPG mRNA, as 506- and 345-bp bands, respectively. The level of HSPG mRNA expression apparently increased in the nephrolithic rat kidney. Immunohistochemical study revealed that increased production of heparan sulfate was detected in both distal and proximal tubules during nephrolithiasis. These findings suggest that increased expression of HSPG may play a significant role during calcium oxalate stone formation.

Animals↗

TrkB signaling modulates spine density and morphology independent of dendrite structure in cultured neonatal Purkinje cells.

Neurotrophins cooperate with neural activity to modulate CNS neuronal survival and dendritic differentiation. In a previous study, we demonstrated that a critical balance of neurotrophin and neural activity is required for Purkinje cell survival in cocultures of purified granule and Purkinje cells (Morrison and Mason, 1998). Here we investigate whether TrkB signaling regulates dendrite and spine development of Purkinje cells. BDNF treatment of purified Purkinje cells cultured alone did not elicit formation of mature dendrites or spines. In cocultures of granule and Purkinje cells, however, continuous treatment with BDNF over a 2 week postnatal culture period increased the density of Purkinje cell dendritic spines relative to controls without causing a shift in the proportions of headed and filopodia-like spines. The increase in spine number was blocked by adding TrkB-IgG to the medium together with BDNF. Although BDNF alone did not consistently modify the morphology of dendritic spines, treatment with TrkB-IgG alone yielded spines with longer necks than those in control cultures. None of these treatments altered Purkinje cell dendritic complexity. These analyses reveal a role for TrkB signaling in modulating spine development, consistent with recently reported effects of neurotrophins on synaptic function. Moreover, spine development can be uncoupled from dendrite outgrowth in this reductionist system of purified presynaptic and postsynaptic neurons.

Animals↗