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Biomedical subjects

A Oshima

Publications and source records attributed to A Oshima.

194 records · Page 11Linked to original sources
PubMedDate not supplied

Splicing defect of the glycoasparaginase gene in two Japanese siblings with apartylglucosaminuria.

Molecular analysis of the glycoasparaginase gene was performed on two Japanese siblings with aspartylglucosaminuria. The cDNA from one patient contained 7 additional bases between exons 3 and 4 (3'-terminal sequence of intron 3). This insertion resulted in a frame shift, and a termination codon appeared at amino acid 146. Amplification and sequencing of genomic DNA detected a single base transition (A-->G) at the 5' side adjacent to the insertion sequence. This mutation created a consensus AG dinucleotide in the splice acceptor site, and produced almost exclusively an abnormal mRNA containing the insertion by alternative splicing. The calculation of the sample score of the acceptor site supported this analytical result. BsmAI restriction site analysis of amplified cDNA and genomic DNA showed that these patients were homozygotes for this mutation. We conclude that the splicing defect in intron 3 causes glycoasparaginase deficiency in these patients.

Asian People↗
PubMedDate not supplied

Two cases of malignant lymphoma complicated by hemophagocytosis resembling orbital cellulitis.

Two patients with malignant lymphoma complicated by hemophagocytic syndrome (HPS) are reported. Their clinical signs at onset were similar to those of orbital cellulitis. Lymphoma complicated by hemophagocytosis is called lymphoma-associated hemophagocytic syndrome (LAHS) and its prognosis is reported to be very poor. As far as we know, this is the first report in the ophthalmological field. In our patients, we suspected that the lesions occurred from the orbit or skin of this area. The first patient was a 22-year-old man and the second patient a 16-year-old girl. The diagnosis was very difficult at the onset of disease. They died within 6 months after the first ophthalmological examination. When orbital cellulitis is suspected and antibiotic therapy is ineffective, we should suspect HPS and should examine serum ferritin, which is a good marker of HPS. Early biopsy and consultation with a hematologist are very important.

Adolescent↗
PubMedDate not supplied

The differential ACTH responses to combined dexamethasone/CRH administration in major depressive and dysthymic disorders.

In a preliminary study, we performed the combined dexamethasone/CRH test on patients with major depressive and dysthymic disorders as well as healthy controls. The ACTH response was significantly enhanced in the major depression group compared to the control group and tended to be heightened compared to the dysthymia group. The cortisol response was not significantly different among the three groups. We assume that major depression and dysthymia are neuroendocrinologically distinct disorders, although whether the difference is quantitative or qualitative remains to be examined.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Psychological, autonomic and neuroendocrine responses to acute stressors in the combined dexamethasone/CRH test: a study in healthy subjects.

The combined dexamethasone/CRH test (DEX/CRH test) is reported to produce augmented ACTH and cortisol responses in various psychiatric disorders as well as in some non-psychiatric conditions. To examine whether stress affects the outcome of DEX/CRH test, two stress groups in a repeated measures design were compared to an age-matched control group with regard to the psychological, autonomic and neuroendocrine responses after the combined dexamethasone and CRH challenge. Cold pressor (4 degrees C, total 10 min) produced stronger subjective distress than mental arithmetic (15 min). Cold exposure, but not the mental test, elevated systolic and diastolic blood pressure, whereas the mental test increased pulse rate and skin conductance level more markedly than cold exposure. Neither stressor produced a significantly enhanced response of ACTH and cortisol in DEX/CRH test, and there was no correlation between psychological and neuroendocrine responses. These findings suggest that different stressors induce different patterns of sympathetic activation and that acute stress is unlikely to affect the results of DEX/CRH test.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Hypothesis: hyperstructures regulate bacterial structure and the cell cycle.

A myriad different constituents or elements (genes, proteins, lipids, ions, small molecules etc.) participate in numerous physico-chemical processes to create bacteria that can adapt to their environments to survive, grow and, via the cell cycle, reproduce. We explore the possibility that it is too difficult to explain cell cycle progression in terms of these elements and that an intermediate level of explanation is needed. This level is that of hyperstructures. A hyperstructure is large, has usually one particular function, and contains many elements. Non-equilibrium, or even dissipative, hyperstructures that, for example, assemble to transport and metabolize nutrients may comprise membrane domains of transporters plus cytoplasmic metabolons plus the genes that encode the hyperstructure's enzymes. The processes involved in the putative formation of hyperstructures include: metabolite-induced changes to protein affinities that result in metabolon formation, lipid-organizing forces that result in lateral and transverse asymmetries, post-translational modifications, equilibration of water structures that may alter distributions of other molecules, transertion, ion currents, emission of electromagnetic radiation and long range mechanical vibrations. Equilibrium hyperstructures may also exist such as topological arrays of DNA in the form of cholesteric liquid crystals. We present here the beginning of a picture of the bacterial cell in which hyperstructures form to maximize efficiency and in which the properties of hyperstructures drive the cell cycle.

Bacteria↗
PubMedDate not supplied

Gastric microcirculatory disturbance and behaviour of leucocytes after thermal injury: intravital observation of arteriovenous shunting channels in the gastric submucosal layer.

In order to investigate the pathogenesis of acute gastric mucosal lesion after thermal injury, microcirculatory disturbance was assessed and observation of the behaviour of leucocytes was performed. Gastric blood flow decreased at 15 min post-thermal injury, and partially improved at 2 h; however, it decreased again at 5 h post-thermal injury. Mucosal microcirculatory disturbance was observed by using vascular labelling with monastral blue B. Deposits of monastral blue B were observed centring mainly on collecting venules but were also observed in the capillaries. Submucosal microcirculatory disturbance was observed through an intravital microscope. The irregularity of the wall and segmental constriction in the venules and presence of an arteriovenous shunting channel was observed in the submucosal layer at 5 h post-thermal injury. The percentage of rolling or sticking leucocytes that passed the confluence of a prevenule and a venule were significantly increased at 5 h after thermal injury. The present study revealed depression of gastric blood flow, mucosal and submucosal microcirculatory disturbance, and a significant increase of rolling and sticking leucocytes in the peripheral part of venules after thermal injury. Leucocyte-endothelial interactions may occur under such conditions and this interaction may play an important role in inducing the microcirculatory disturbance that results in an acute gastric mucosal lesion after thermal injury. The present study also demonstrated the possibility of intravital study of gastric submucosal arteriovenous shunting channels.

Animals↗
PubMedDate not supplied

Scavenger effect of elastase on calcifications in liver, kidney and central nervous system tissues of rabbits with atherosclerosis induced by cholesterol-rich diet.

The inhibitory effect of elastase on calcification in liver, kidney and the central nervous system (CNS) was studied in rabbits with atherosclerosis induced by a cholesterol-rich diet. A total of 25 male rabbits were divided into six groups. In the first three groups, rabbits received a standard diet, a 1.5% cholesterol-rich diet or a 1.5% cholesterol-rich diet with intraperitoneal elastase (450 IU/kg.day) for 3 months. In the second three groups, rabbits received a standard diet, a 0.67% cholesterol-rich diet or a 0.67% cholesterol-rich diet with intraperitoneal elastase (450 IU/kg.day) for 6 months. Tissue calcium levels were then determined by neutron activation analysis. Tissue lipid levels were also measured. Dietary cholesterol increased serum lipid levels, atherosclerotic lesions and calcium levels in the CNS, but not in the liver or kidney. Calcium levels in the cerebellum and spinal cord of rabbits receiving the 0.67% cholesterol-rich diet plus elastase were significantly lower than those of rabbits receiving the 0.67% cholesterol diet alone. Elastase had a gradual inhibitory effect on the increase in calcium levels in CNS of cholesterol-induced atherosclerotic rabbits, reduced the increase in serum lipids and decreased the incidence of atherosclerotic lesions.

Animals↗
PubMedDate not supplied

Calcium, phosphorus and aluminium concentrations in the central nervous system, liver and kidney of rabbits with experimental atherosclerosis: preventive effects of vinpocetine on the deposition of these elements.

Calcium, phosphorus and aluminium concentrations in the central nervous system, liver and kidneys were determined in 16 rabbits with atherosclerosis experimentally induced by a cholesterol-rich diet and the protective effect of 3 or 10 mg/kg.day vinpocetine (14-ethoxycarbonyl-(3 alpha,16 alpha-ethyl)-14,15-eburnamenine) given orally on the deposition of these elements was assessed. Rabbits fed a cholesterol-rich diet developed atherosclerosis after 3 months and these rabbits possessed high concentrations of calcium, phosphorus and aluminium in the central nervous system, determined by neutron activation analysis. In atherosclerotic rabbits fed a vinpocetine supplement, there was a decrease in concentrations of these elements in tissues. It is suggested that calcium, phosphorus and aluminium may be implicated in the aetiology of atherosclerosis and that vinpocetine may have a preventive action on the deposition of these elements in central nervous tissue, liver and kidney.

Aluminum↗
PubMedDate not supplied

Effects of ibudilast on calcium deposition in soft tissues of rabbits with atherosclerosis.

The effects of 2.5 mg/kg.day ibudilast, with or without 300 mg/kg.day nicomol, or 10 mg/kg.day ibudilast on calcium and magnesium concentrations in the central nervous system (CNS), heart, liver, kidney, skeletal muscle, abdominal aorta and bone were determined in rabbits fed a 1% cholesterol-rich diet for 3 months. Serum thromboxane B2 concentrations were reduced in rabbits treated with 10 mg/kg.day ibudilast or with 2.5 mg/kg.day ibudilast plus 300 mg/kg.day nicomol, and atherosclerotic lesions were ameliorated compared with untreated rabbits. Calcium concentrations in the frontal cortex and cerebellum were lower in ibudilast/nicomol-treated rabbits and in those fed a standard diet compared with those receiving a cholesterol-rich diet only. Calcium concentrations in the pons and abdominal aorta were also lower in ibudilast/nicomol-treated rabbits whereas the calcium concentrations in the cerebellum were lower in rabbits treated with either 2.5 or 20 mg/kg.day ibudilast. There were no significant changes in tissue magnesium concentrations after feeding a cholesterol-rich diet, with or without drug treatment. It is concluded that 2.5 mg/kg.day ibudilast plus 300 mg/kg.day nicomol or 10 mg/kg.day ibudilast produced a scavenger effect on calcium deposited in the CNS and abdominal aorta of rabbits fed a cholesterol-rich diet.

Animals↗
PubMedDate not supplied

Effects of bifemelane hydrochloride on atherosclerosis in aged rats fed low-calcium diets.

The preventative effects of bifemelane (4-(o-benzylphenoxy)-N-methylbutylamine hydrochloride) on atherosclerosis in aged rats fed low-calcium diets were investigated. Male 18-month-old Wistar rats were maintained for 90 days on the following: (A) standard diet (n = 7), (B) low calcium, low magnesium, high aluminium diet (n = 8), (C) standard diet plus oral intubation with 10 mg bifemelane/kg daily (n = 6), (D) low calcium and magnesium, high aluminium diet plus oral intubation with 10 mg bifemelane/kg daily (n = 6). All groups were give these diets and water ad lib for 90 days, after which blood samples were taken from the abdominal aorta and samples of aorta were examined for atherosclerotic changes. The serum concentrations of the following were determined: calcium, magnesium, zinc, aluminium, inorganic phosphorus, cholesterol, glutamate-oxaloacetate transaminase, glutamate-pyruvate transaminase, lactate dehydrogenase, cholinesterase, creatine phosphokinase, blood urea nitrogen and N-terminal parathyroid hormone. The only significant differences between the groups in serum chemistry were reduced concentrations of cholinesterase and magnesium in groups B and D, increased aluminium in group B, and increased N-terminal parathyroid hormone in groups B and D. In groups C and D the atherosclerosis was much improved compared with that in groups A and B. It appears that bifemelane largely prevents atherosclerosis caused by calcium deposition in the arteries of rats fed low-calcium diets, due to its effect in maintaining magnesium and calcium in bones.

Aluminum↗
PubMedDate not supplied

Evolution of subpatent parasitaemia in Trypanosoma cruzi chronically infected mice with the help of a cyclophosphamide amplification transfer assay.

We have evaluated the sensitivity of the classical blood subinoculation method, modified through cyclophosphamide treatment of transferred mice, for the detection of occult parasitaemias in Trypanosoma cruzi chronically infected mice. Besides its simplicity, the method was shown to be highly sensitive for both the "chronic" phase parasites (99% of chronic cases were shown to harbour occult parasitaemias) and for the acute phase parasites (T. cruzi could be detected in 53.8% of animals transferred with one Y strain parasite and in 20% of animals transferred with one CL strain parasite). Using acute phase bloodforms, the assay proved to be more sensitive than conventional subinoculation when dealing with the CL, but not the Y strain of the parasite. With the help of this parasite detection tool, we have studied during a one year period, the evolution of subpatent parasitaemias in a group of mice which survived through chemotherapy from lethal acute phase of T. cruzi infection. Cyclophosphamide transfer assay revealed occult parasitaemias in 100% of the chronic animals, nevertheless, continuous and discontinuous patterns of positivity were observed.

Acute Disease↗
PubMedDate not supplied

An in vitro model for human endothelial cell seeding of a small diameter vascular graft.

A precise system was devised to measure the kinetics of attachment of human venous endothelium to a variety of materials and substrates. Cells were labelled in a postconfluent state with tritiated thymidine, harvested, and a cell suspension seeded into a 4 mm PTFE graft. After a 90 minute incubation period, one half of the graft segment was sacrificed and the remaining portion placed in a perfusion system (225 cc/min) for 1 hour. Graft segments, effluents, and seeding suspension were assayed in a beta scintillation counter. The percentage of cells that attached pre- and postperfusion were determined, as well as the retrieval of tritium from the system. Initially, 71% of seeded cells attached to grafts coated with fibronectin, with significantly less (60%) remaining attached after perfusion. Only 10% of cells initially attached to uncoated grafts, with 4% retained postperfusion. Retrieval of tritium averaged 102 +/- 10% for all experiments. This system determines both pre- and postperfusion attachment of human endothelial cells to vascular grafts following manipulation of numerous variables, including graft material, substrate, incubation time, and seeding density. An optimal seeding protocol for human trials can thus be determined.

Blood Vessel Prosthesis↗
PubMedDate not supplied

Disseminated intravascular coagulation caused by abdominal aortic aneurysm.

A 71-year-old male with disseminated intravascular coagulation (DIC) caused by abdominal aortic aneurysm was successfully treated surgically. He had aortic regurgitation, an old myocardial infarction, and nephrotic syndrome. The infrarenal part of the inferior vena cava, which was on the left side of the aneurysm, was temporarily transected during the surgical procedure. Preoperative heparin therapy was insufficient, but infusion of blood components during the operation and minimal dissection of the aneurysm were effective in controlling intraoperative hemorrhage. Hypofibrinogenemia and thrombocytopenia were normalized immediately after operation, and hemorrhagic diathesis was completely cured. In this case, the definitive treatment of DIC caused by an abdominal aortic aneurysm war removal of the lesion and the infusion of coagulation factors during the operation was effective in minimizing blood loss.

Aged↗