Biomedical subjects

H Tamii

Publications and source records attributed to H Tamii.

3 recordsLinked to original sources

PubMed1996

The effects of repetitive mild brain injury on cytoskeletal protein and behavior.

The purpose of this study was to examine the hypothesis if repetition of mild mechanical brain injury induces the pathological process related to Alzheimer's disease. After defining the magnitude of the subthreshold brain injury which does not induce brain tissue damage by a single hit, the subthreshold mild impact (1.0 atm) was repeated 7 times every 24 h. One week after the last impact, abnormal accumulation of microtubule-associated protein 2 (MAP2) and phosphorylated neurofilament 200 kD (p-NFH) was observed in neuronal perikarya and dendrites. One month after percussion, the number of MAP2-and p-NFH-positive neuronal perikarya was increased and observed in remote areas including the contralateral cortex and the hippocampus. Tau-1 immunoreactivity was increased in deep cortical neurons of the ipsilateral side after dephosphorylation, indicating the accumulation of phosphorylated tau in neuronal perikarya. The abnormal accumulation of cytoskeletal proteins in neuronal perikarya may be due to impaired axonal transport caused by mechanical brain injury. The behavioral study revealed that after repetitive mild percussion, rats show less efficient habituation to a new environment. It is suggested that the repetition of subthreshold mechanical brain injury may trigger cytoskeletal alteration related to neuronal degeneration.

Alzheimer Disease↗

PubMed1994

[Hemodynamics during hypervolemic hemodilution (HH) technique].

In order to avoid blood transfusion in patient, we have been carrying out hypervolemic hemodilution (HH) with HES and Ringer's lactate without blood withdrawal. We studied the hemodynamics during hypervolemic hemodilution in adult mongrel dogs. The dogs were divided into two groups; control group (group C) and nitroglycerin group (group N) in which nitroglycerin was administrated at 1 microgram.kg-1.min-1. During HH, CVP, PAP, PCWP increased remarkably, and they were lower in group N than in group C, and CO increased in group N more than in group C. Though by the acute hemodilution Hct decreased to 30%, PaO2/FIO2, pH, and SvO2 remained within normal ranges. We conclude that HH is a very useful technique to avoid blood transfusion. However, during HH the excessive volume loading is associated with significant increase in CVP and PCWP, and the vasodilating therapy is effective to reduce the volume overloading.

Animals↗

PubMed1993

[Evaluation of the peripheral circulation during surgery by the difference between the central and peripheral temperature].

The peripheral circulation during surgery was evaluated by the difference between rectal and sole deep temperature (RT-SDT) in 160 patients. Moreover it was investigated whether the peripheral circulation is influenced by the operation site, the method of anesthesia, the age of patient, the volume of infusion and blood loss. In many patients during intracranial, thoracic and upper abdominal surgeries, RT-SDT dissociated with time. But the change of RT-SDT varied with the anesthetic method. During upper abdominal surgery, RT-SDT tended to dissociate wtih the halothane (H) or enflurane (E)+N2O anesthesia and the wide dissociation was observed with fentanyl+droperidol+N2O anesthesia (NLA) on and after the 4th hour during the surgery. In contrast, RT-SDT continued to converge throughout the surgery in H or E+N2O+epidural anesthesia. The influence on RT-SDT of age, volume of infusion and blood loss, varied with the anesthetic method also. RT-SDT on the 4th hour during surgery correlated with the age of the patient, the volume of infusion in the H+N2O anesthesia, and with the volume of blood loss under NLA. The peripheral circulation during the surgery is affected seriously by anesthesia and the site as well as time of the operation. Therefore the anesthetic method should be selected in consideration of the type, length and site of operation. Some counter-measures should be taken in order to maintain good peripheral circulation in long operations.

Adult↗