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Biomedical subjects

T Komatsu

Publications and source records attributed to T Komatsu.

At least 289 records · Page 16Linked to original sources
PubMed1989

Determinants in the 5' noncoding region of poliovirus Sabin 1 RNA that influence the attenuation phenotype.

A number of recombinants between the virulent Mahoney and attenuated Sabin strains of type 1 poliovirus were constructed by using infectious cDNA clones of the two strains. To identify a strong neurovirulence determinant(s) residing in the genome region upstream of nucleotide position 1122, these recombinant viruses were subjected to biological tests, including monkey neurovirulence tests. The results of the monkey neurovirulence tests suggested the important contribution of an adenine residue (Mahoney type) at position 480 to the expression of the neurovirulence phenotype of type 1 poliovirus. This nucleotide, however, had only a minor effect, if any, on viral temperature sensitivity. Monkey neurovirulence tests on the recombinant virus whose genome had a guanine residue (Sabin type) at position 480 and variants generated from this recombinant virus in the central nervous system of monkeys strongly suggested that only one nucleotide change, from adenine to guanine, was not sufficient for full expression of the attenuation phenotype encoded by this genome region. These results suggest that the expression of the attenuation phenotype depends on the highly ordered structure formed in the 5' noncoding sequence and that the formation of such a structure is possibly influenced by the nucleotide at position 480. Furthermore, in vitro biological tests performed on viruses recovered from the central nervous system of monkeys injected with a temperature-sensitive recombinant virus showing the small-plaque and d phenotypes revealed that most of the recovered viruses had even higher temperature sensitivities and that all of the recovered viruses that had acquired the large-plaque phenotype had lost the d phenotype to some extent. These results indicate that there may be an unknown selection pressure(s) in the central nervous system and that common determinants might be involved in the expression of the small-plaque and d phenotypes.

Animals↗
PubMed1989

Effects of 2(3)-tert-butyl-4-hydroxyanisole pretreatment on cefpiramide binding to mouse glutathione S-transferases.

Binding of cefpiramide (CPM) and other beta-lactam antimicrobial agents to 2(3)-tert-butyl-4-hydroxyanisole (BHA)-induced liver glutathione (GSH) S-transferases (EC 2.5.1.18) from CD-1 mice was studied. A marked induction of hepatic GSH S-transferase from mice fed BHA was observed. Gel chromatography of liver cytosol from mice fed BHA showed an increased binding of CPM, cefotetan and cefazolin to BHA-induced GSH S-transferases. The extent of their binding to GSH S-transferase seemed to be correlated with the extent of their excretion into the bile. Binding of CPM to the GSH S-transferase fraction was inhibited by both indocyanine green, which is known to bind liver GSH S-transferases intensively, and by cefoperazon, which is mainly excreted into the bile. This study suggests that GSH S-transferases are the main binding proteins of CPM in the liver cytosol fraction and play an important role as carrier proteins of CPM and some antimicrobial agents in mouse liver.

Animals↗
PubMed1989

Model of a new generation of tracheostomy and endotracheal tubes. A preliminary study of sensors to monitor obstruction.

The feasibility of monitoring cannula obstruction was studied by conversion of the electrical resistance of substances that are capable of causing obstruction into audible auditory signals. Copper-nickel-gold electrodes were thermal pressed onto polyimide-based flexible films placed as 1-mm wide strips along the inner surface of tracheostomy and endotracheal tubes. The responses were fed into a resistance-to-frequency converter (IC 555 timer), and the output was frequency selected to generate auditory responses through a piezoelectric beeper. Quantitative estimates of responses from the IC output were computer averaged. Instantaneous obstruction detection was made possible by the immediate responsiveness of the device in the presence of obstruction.

Airway Obstruction↗
PubMed1989

Synthesis and antitumor properties of N1-acyloxymethyl derivatives of bis(2,6-dioxopiperazines).

Many N1-acyloxymethyl derivatives VI of bis(2,6-dioxopiperazine) I, ICRF-154, were prepared and tested for antitumor activity. The treatment of I with formaldehyde gave a crystalline bis(N1-hydroxymethyl) derivative VII, which was acylated under various conditions to give bis(N1-acyloxymethyl) derivatives VI. Antitumor activity of VI against P388 leukemia in mice was studied. Several bis(N1-acyloxymethyl) compounds such as phenylacetyloxymethyl VI-6, methoxycarbonyloxymethyl VI-41, isobutoxycarbonyloxymethyl VI-44, and furancarboxymethyl VI-38 compounds were found to have potent antitumor activities. On the other hand, water-soluble esters having an amine or a carboxylic acid function in their acyl groups showed rather reduced activity. These bis(N1-acyloxymethyl) derivatives VI were presumably hydrolyzed into the parent bis(2,6-dioxopiperazine) I by nonspecific esterase in the body to exhibit their antitumor activity.

Animals↗
PubMed1989

[A case of left atrial ball thrombus observed in a patient with combined valvular heart disease, accompanying anomalous coronary venous run].

A 53-year woman, who had been under observation for combined valvular heart disease, was admitted to our hospital for further examination of embolic episodes to brain and kidney. Echocardiographic examination showed the evidence of free-moving ball thrombus in the left atrium, and emergent cardiac catheterization following the echocardiography confirmed the diagnosis of it as well as mitral stenosis, aortic regurgitation with stenosis, and tricuspid regurgitation. In addition, coronary angiography disclosed the anomalous coronary venous run. With these findings, the cause of embolic episodes was found to be due to the thrombus in the left atrium. In the surgery performed a ball thrombus of 40 x 35 x 36 mm and a mural thrombus of 15 x 35 x 20 mm in size in the left atrium were detected and removed, and both mitral and aortic valves were replaced to artificial ones. She had a good hospital course after the surgery and discharged without any complication. In this report, we discussed a case of left atrial thrombus observed in a combined valvular heart disease, with 29 literatures reported in our country.

Coronary Vessel Anomalies↗
PubMed1989

[An immunohistochemical study of normal sweat glands using an antibody to the breast cyst fluid protein (GCDFP-15)].

In this study, we applied the antibody against the molecular weight 15,000 protein purified from breast cyst fluid (GCDFP-15) to cutaneous tissue, especially to sweat glands. Breast cyst fluid was obtained by needle aspiration from patients with gross cystic disease. DEAE-cellulose column chromatography was performed and followed by SDS-polyacrylamide gel electrophoresis. Antisera against the purified protein were prepared in rabbits. We stained specimens of normal skin by the PAP method. The normal apocrine gland cells were strong positive and eccrine gland dark cells were positive. Eccrine gland clear cells were weak positive or negative. Duct cells of both glands were negative. From these observations, we suggest that this antibody is useful for detecting seromucous cells of sweat glands, including both the apocrine gland cells and eccrine dark cells in the skin.

Animals↗
PubMed1989

[An immunohistochemical study of cutaneous tumors using an antibody to the breast cyst fluid protein (GCDFP-15)].

The antibody against a molecular weight 15,000 protein isolated from the breast cyst fluid (GCDFP-15) was applied to tissue from cutaneous tumors, especially to sweat gland tumors. This protein was purified from the breast cyst fluid; antisera was prepared in rabbits. Ninety six cases of cutaneous tumors were stained by the PAP method. Apocrine hydrocystoma, syringocystadenoma papilliferum, so-called mixed tumor of the skin, extramammary Paget's disease, microcystic adnexal carcinoma, and mucinous carcinoma of the skin were positively stained. Eccrine poroma, eccrine spiradenoma, syringoma, eccrine hydrocystoma, papillary eccrine adenoma, adenoid type of basalioma were negative. These observations indicate that the positively stained tumors have functioning seromucous cells, which are characteristic of apocrine gland cells and eccrine dark cells in the skin.

Animals↗
PubMed1988

Effects of early antigen exposure through lactation on later specific antibody responses in mice.

This study characterized totally the effects of early Ag exposure by the suckling route on later specific antibody responses. When mother mice of BALB/c or C57BL/6 strains were injected with deaggregated human gamma-globulin (HGG) immediately after delivery, total amounts of HGG in sera of offspring increased until 2 wk of age. The catabolism of transferred HGG was extremely slow and the half-life was about 3 wk in both strains. Hence, small amounts of Ag in mothers, 0.5 micrograms in C57BL/6 and 50 micrograms in BALB/c, could tolerize their offspring effectively. As these were minimum tolerogenic doses, the strain difference in ease of tolerance induction is apparent already during suckling. The study on timing dependent effects of HGG-specific antiserum on tolerance induction by mothers given 50 micrograms HGG demonstrated that the tolerance is achieved within the 1st wk of lactation in C57BL/6 offspring, but not in BALB/c offspring, and the restoration from the tolerance needs more than 6 wk under circumstances, supposedly, without free Ag. Whereas the tolerance was induced in a dose-dependent manner in each class of antibody, the dissociation of tolerant states between IgM, IgG, and IgE antibody classes was found in C57BL/6 offspring. It is interesting that C57BL/6 offspring were sensitized weakly, but significantly, by mothers given subtolerogenic doses. However, this was not apparent in BALB/c. Thus, the Ag dose and the animal strain are related closely to the consequences of this Ag exposure. The aging of suckling mice within the first 2 wk of life or immunomodulators administered early in life did not seriously affect the consequences. Studies on a cellular basis showed that the tolerance is caused by the selective defect in helper T cell function and the suppressor cell activity is not associated with the mechanisms. This contrasts with other models of oral tolerance.

Adjuvants, Immunologic↗
PubMed1988

A recombinant virus between the Sabin 1 and Sabin 3 vaccine strains of poliovirus as a possible candidate for a new type 3 poliovirus live vaccine strain.

Biological tests including the monkey neurovirulence test performed on recombinants between the virulent Mahoney and attenuated Sabin 1 strains of type 1 poliovirus indicated that the genome region encoding mainly the viral capsid proteins had little correlation with the neurovirulence or attenuation phenotype of the virus. The results suggested that new vaccine strains of type 2 and type 3 polioviruses may be constructed in vitro by replacing the sequence encoding the antigenic determinants in viral capsid proteins of the Sabin 1 genome by the corresponding sequences of the type 2 and type 3 genome, respectively. Accordingly, we constructed recombinants between the Sabin 1 and Sabin 3 strains of poliovirus in which genome sequences of the Sabin 1 strain encoding most or all capsid proteins were replaced by the corresponding genome sequences of the Sabin 3 strain. One of the recombinant viruses thus constructed was fully viable and showed antigenicity and immunogenicity identical to those of type 3 poliovirus. The monkey neurovirulence tests and in vitro phenotypic marker tests (temperature sensitivity of growth, sodium bicarbonate concentration dependency of growth under agar overlay, and size of plaque) were performed on the recombinant virus. The stability of the virus in regard to the temperature sensitivity phenotype was also tested. The results suggested that the recombinant virus is a possible candidate for a new type 3 poliovirus vaccine strain.

Animals↗
PubMed1988

Use of pulse oximetry for monitoring tracheostomy tube obstruction.

Experimental studies were performed on dogs for monitoring postoperative tracheostomy tube obstruction using a pulse oximeter. While a 25% obstruction of the cross-sectional area of the tube did not alter the oxygen saturation, obstruction of 40% and above resulted in a drop in the oxygen saturation level which corresponded to the degree of obstruction. The greater the degree of obstruction, the sooner was the fall of oxygen saturation. Therefore a pulse oximeter could be effectively put to use to monitor tracheostomy tube obstruction.

Animals↗
PubMed1988

Morphological studies of the upper end of the femur. II. Macroscopic, radiological, histological and histomorphometrical studies.

Fragments of bone from the proximal femur were obtained at autopsy. Macroscopic, radiological and histological studies were then performed on these specimens, and the following observations were made: 1) It was possible to classify the bone marrow into four groups based on the distribution and volume of the red and yellow marrow. 2) The radiological findings were classified into four groups according to the degree of bone loss, as in aging. 3) The histomorphometrical studies of the femoral neck by undecalcified ground section showed a decrease in bone area with aging. In the female, scalloped and osteoid surface increased with age in the medial cancellous bone as did scalloped surface in the lateral. This observation may explain the age-related bone fragility of the femoral neck, especially in the elderly females.

Adult↗
PubMed1988

An immunohistochemical and ultrastructural study of an unusual case of multiple non-X histiocytoma.

An immunohistochemical and ultrastructural study of an atypical case of multiple non-X histiocytoma was done. There was involvement of the skin, lungs, and liver in a 3-month-old male infant. Microscopic examination of the cutaneous tumors revealed a dense infiltration of cells with polymorphous large nuclei and abundant eosinophilic cytoplasm in the entire dermis. Both immunohistochemical and electron microscopic studies suggested that the tumors were non-X histiocytomas. The patient's condition deteriorated with dyspnea due to rapid enlargement of tumor masses in the liver and lungs. However, at 5 months of age, the cutaneous nodules and pulmonary and hepatic lesions showed a tendency to involute. Furthermore, at 12 months of age, they were no longer detectable. The patient at 24 months of age was well with normal development. To date, no recurrence of the disease has been observed.

Biopsy↗
PubMed1987

Severe cardiovascular changes associated with pancuronium after cardiopulmonary resuscitation and after brain injury.

Severe hypertension, tachycardia or ECG changes have been reported following i.v. administration of pancuronium to patients with pheochromocytoma or bronchial asthma. These cardiovascular changes were explained by an interaction between autonomic effects of pancuronium and elevated serum catecholamines or aminophylline. We noted similar cardiovascular changes associated with i.v. administration of pancuronium in two patients after successful cardiopulmonary resuscitation and in two with midbrain hemorrhage and epidural hematoma. In these patients, pancuronium produced no abnormal cardiovascular changes when given during elective surgery or before the occurrence of midbrain hemorrhage. Thus, ischemic brain damage may play a role in producing the severe cardiovascular changes associated with pancuronium.

Aged↗