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Biomedical subjects

M Nakai

Publications and source records attributed to M Nakai.

At least 343 records · Page 19Linked to original sources
PubMed1987

[A bronchogenic cyst of the esophageal wall--a case report and differential diagnosis from an esophageal cyst].

A 25-year-old man underwent extirpation of a cystic mass of the esophageal wall. It proved to be an unilocular cyst surrounded by a pseudo-stratified, ciliated columnar epithelium with occasional goblet cells. Outside of the epithelium, a smooth muscle layer was seen and a small foci of seromucous glands were scattered in the wall. Electron microscopic observations of the epithelial layer revealed 5 types of the cells: ciliated columnar cells, mucous cells, brush cells, intermediate cells, and basal cells. Our results suggest that electron microscopic observations are useful for distinguishing the bronchogenic cyst from the esophageal cyst. Nine cases of para-esophageal bronchogenic cysts that have been reported in Japan also are briefly reviewed.

Adult↗
PubMed1986

The N-terminal 21 amino acids of a 70 kDa protein of the yeast mitochondrial outer membrane direct E. coli beta-galactosidase into the mitochondrial matrix space in yeast cells.

The intracellular location of fusion proteins was investigated in yeast cells. They consisted of the N-terminal 21, 61 or 292 amino acids of the 70 kDa protein of the yeast mitochondrial outer membrane and an enzymatically active E. coli beta-galactosidase. The hybrids containing 61 or 292 residues of the 70 kDa protein, as well as the original 70 kDa protein, were localized on the outer membrane in a tightly membrane-bound form. In contrast, the other hybrid was exclusively localized in the mitochondrial matrix space as a soluble protein.

Cytosol↗
PubMed1986

High-affinity receptor-mediated internalization and degradation of interleukin 2 in human T cells.

Receptor-mediated internalization and degradation of IL-2 were investigated in cell lines carrying human T cell leukemia/lymphoma (lymphotrophic) virus type I (HTLV-I) and PHA-treated normal PBL. The HTLV-I-carrying cell lines ILT-Yan and TL-Mor, and the PBL expressed both high- and low-affinity IL-2-R. However, another HTLV-I-carrying T cell line, MT-1, expressed mainly low-affinity receptors. Greater than 50% of the IL-2 bound to high-affinity receptors was internalized within 10 min when these cells were incubated at 37 degrees C. The internalized IL-2 was rapidly degraded and the products were excreted into the culture fluid. The t1/2 of IL-2 degradation in these cells was estimated as 60-80 min at 37 degrees C. The internalization and degradation of IL-2 were both temperature dependent. Light-microscopic autoradiography with 3H-labeled IL-2 confirmed the internalization of IL-2, and suggested that some IL-2 might be carried to the nucleus.

Cell Compartmentation↗
PubMed1986

Distribution profiles of keratin proteins during rat amelogenesis.

We examined rat cells undergoing amelogenesis for the presence of three types of keratin proteins using a polyclonal antibody to keratin (against total keratins (TK) with molecular masses ranging from 41 to 65 kilodaltons (kd) and monoclonal antibodies keratins to KL1 and PKK1 (reactive with keratins with molecular masses of 55-57 and 41-56 kd, respectively). In normal oral epithelia from young rats, the TK, KL1, and PKK1 antibodies bound to all of the epithelial strata. The epithelial cap on the top of incisors and the dental lamina of molar teeth exhibited strong TK staining, moderate staining KL1, and little or no PKK1 staining. In developing molar enamel organs, both the outer and inner enamel epithelia, the stratum intermedium, and stellate reticulum cells were all positively stained by the TK immunoreagent. In developing incisors, TK only bound strongly to stratum-intermedium cells, and no KL1 and PKK1 staining antibodies was observed in ameloblasts or the stratum intermedium.

Amelogenesis↗
PubMed1986

Immunohistochemical distribution of monoclonal antibodies against keratin in papillomas and carcinomas from oral and nasopharyngeal regions.

Papillomas (40) and squamous cell carcinomas (75) were examined for the presence of three keratin proteins with the use of an immunohistochemical technique. Polyclonal keratin antibody (TK, detecting 41 to 65 kDa keratin) and monoclonal antibodies KL1 and PKK1 (55 to 57 kDa and 41 to 56 kDa, respectively) were used. Squamous epithelium in normal oral mucosa showed marked TK staining in cells of upper strata and relatively slight staining in basal layer cells, moderate KL1 staining in spinous and granular layers and was negative in basal cells. Positive PKK1 staining was noted in cells of the basal layer. Columnar epithelium in the nasal mucosa showed TK staining in all layers, KL1 staining on the apical side of epithelial cells and trace or negative staining in basal layer cells. There was moderate PKK1 staining along the apical side of cells and variable staining in basal cells. Keratin distribution in oral papillomas was similar to that in normal oral epithelium, whereas in nasal and nasopharyngeal papillomas, keratin distribution was restricted to the upper layers. Tonsillar papillomas showed a strong TK reaction, negative KL1 in upper layer cells, and marked PKK1 staining in basal cells. Well-keratinized squamous carcinomas indicated an irregular TK distribution and decreased KL1 and negative PKK1 stainings. Intermediate and poorly differentiated keratinizing squamous carcinoma showed irregular staining patterns for the three classes of keratins studied. Immunohistochemically detectable keratins utilizing monoclonal antibodies were described as useful markers of epithelial tumors of squamous origin. Keratin expression within benign tumors was related to normal regional distribution, whereas in malignant tumors, keratin distribution was irregular in its distribution profile.

Antibodies, Monoclonal↗
PubMed1986

Relevance of location of defect and pulmonary vascular resistance to the intracardiac pattern of left-to-right shunt flow in dogs with experimental ventricular septal defect.

Left-to-right (L-R) shunting across a ventricular septal defect (VSD) often involves a direct VSD-pulmonary arterial component (jet) that surges from the VSD immediately into the pulmonary artery. We used the thermodilution technique in dogs with acute experimental VSD to quantify this component. In dogs with supracristal VSD (n = 7), the direct component represented 76 +/- 4% (mean +/- SE) of the total L-R shunt on average, vs 39 +/- 7% (p less than .001) of the total in dogs with infracristal VSD and the same level of L-R shunting (n = 6). The direct component can be expected to impose additional hyperkinetic forces on the pulmonary artery since it is driven by the left ventricular pressure. Although not yet clinically proven, we speculate therefore that patients with supracristal VSD may be at greater risk of becoming jeopardized by late-onset pulmonary vascular obstructive disease. Since a part of the total shunt other than the direct component dropped into the right ventricle, the right ventricle bore only 24% of the total shunt in supracristal VSD, but 61% in infracristal VSD. We also found that the amount of direct component was decreased, and therefore another part must have increased, as the pulmonary vascular resistance was artificially raised. As a second speculation, therefore, we suggest that patients with supracristal VSD may have less enlargement of the right ventricle than those with infracristal VSD before pulmonary hypertension develops.

Animals↗
PubMed1986

Functional characteristics of intramyocardial capacitance vessels during diastole in the dog.

In order to evaluate the functional characteristics of the intramyocardial capacitance vessels during prolonged diastole, we analyzed the response of coronary vein flow after stepwise changes of coronary artery pressure in anesthetized open-chest dogs by using our newly developed laser Doppler velocimeter with an optical fiber. The peripheral portion of the great cardiac vein was isolated and the optical fiber tip was inserted into the vessel. The left anterior descending coronary artery was cannulated and connected to a reservoir to regulate coronary perfusion pressure. Intracoronary adenosine administration was carried out to avoid any change in coronary vasomotor tone. After 15 seconds of occlusion of the perfusion route, the heart was arrested by pacing-off. Two seconds later, coronary perfusion pressure was increased stepwise to a preset target pressure. This procedure was repeated by changing target pressure at 4 (or 5) different pressure levels (31-105 mm Hg). The great cardiac vein flow became zero due to the cardiac arrest and remained at zero for a moment (dead time) after the initiation of reperfusion. Then the flow reappeared and increased with first order time delay. The presence of dead time indicates the existence of unstressed volume, and the first order time delay represents the product of resistance and capacitance. The unstressed volume with a minimal vasomotor tone for perfusion pressure of 60-90 mm Hg was 5.2 +/- 2.2 ml per 100 g left ventricle, which is comparable to coronary blood flow for several beats. The capacitance at perfusion pressure of 60-90 mm Hg was 0.08 +/- 0.04 ml/mm Hg per 100 g left ventricle, while that at low perfusion pressure (30-50 mm Hg) was 0.14 +/- 0.09 ml/mm Hg per 100 g left ventricle. These results indicate that the intramyocardial capacitance vessels have two functional components, and that the phasic nature of coronary vein flow is solely the result of the myocardial squeezing of the blood in the capacitance vessels.

Animals↗
PubMed1986

An in situ experimental model in rabbits for the study of rectal absorption.

An in situ experimental model of rectal absorption was studied in rabbits compared with in vivo determination of drug concentration in the plasma of postcaval vein using indomethacin as drug. Pharmacokinetic parameters were similar between in vivo and in situ. When results from both studies were compared, 60% of the drug administered to the rectum was absorbed from the superior hemorrhoidal vein and the remaining 40% was absorbed from the inferior hemorrhoidal vein. When an aspirin suppository was used in this model, the amount of unaltered aspirin absorbed in the rectal mucosa or space was greater than the absorbed salicylic acid which was metabolized or degradated from aspirin. In the case of insulin, these differences were not seen in the insulin concentration of venous plasma between insulin physiological saline and surfactant suspension. However, using the in situ model, the surfactant effect on rectal absorption of insulin was observed. From the above results, it was concluded that this in situ experimental model of rectal absorption has advantages in that it can be used directly to measure the rectal absorption rate and to determine ratios of easily metabolized and poorly absorbed drugs. Therefore, this model appears to be useful in evaluation of rectal absorption.

Animals↗
PubMed1986

Enhanced vasopressin release upon activation of the central neural mechanism in spontaneously hypertensive rats.

Monopolar electrical stimulation of the intermediate portion of the solitary nucleus in spontaneously hypertensive rats (SHRs) with cervical cordotomy and vagotomy resulted in a 1.68 times greater increase in plasma vasopressin concentration than in Wistar rats. The result implies that such an enhanced function of the central neural mechanism to release vasopressin in SHR backs up the functionally aberrant cardiovascular receptors.

Animals↗
PubMed1986

Acute systemic and regional hemodynamic effects of alpha 1-adrenoceptor blockade in conscious spontaneously hypertensive rats.

The acute hemodynamic effect of the selective alpha1-antagonist, 2-[4-(n-butyryl)-homopiperazine-1-y1]-4-amino-6,7-dimethoxy-quinazoline (bunazosin; E-643), was studied by the microsphere technique in 62 conscious spontaneously hypertensive rats. We found that a large fall in total peripheral resistance with a moderate increase in cardiac output accounted for the moderate decrease in arterial pressure; the heart rate did not change; the skeletal muscle, brain, heart, and gastrointestinal tract sensitively dilated, and kidney less sensitively dilated, their resistance vessels, with little change in their blood flow.

Adrenergic alpha-Antagonists↗
PubMed1986

Evaluation of human coronary blood flow with an 80 channel 20 MHz pulsed Doppler velocimeter and zero-cross and Fourier transform methods during cardiac surgery.

To evaluate local blood flow velocities accurately at many sampling points in small vessels, especially in human coronary arteries, we have developed an 80 channel 20 MHz pulsed Doppler velocimeter. Doppler signals from 80 channels are detected by a zero-cross method and a signal from an optional channel is analyzed by a fast-Fourier transform method, both in real time. Basic experiments using a model and animals have demonstrated the accuracy and utility of our method of measurement of blood flow velocity for both nondisturbed and disturbed flow. Velocity waveforms in a native coronary artery beyond a vein bypass graft insertion were measured during cardiac surgery. They showed a diastolic-predominant pattern with a small systolic component. During transient graft occlusion, the waveforms changed to a systolic-predominant pattern in a patient with severe stenosis and to a to-and-fro pattern in a patient with total occlusion. In a patient with severe aortic regurgitation, the coronary arterial velocity waveforms exhibited a systolic-predominant pattern with a broad velocity spectrum. After aortic valve replacement, however, a diastolic-predominant pattern with a narrow spectrum was observed.

Blood Flow Velocity↗
PubMed1986

[Intravascular papillary endothelial hyperplasia of the breast--report of a case with scanning electron microscopic observations].

A 65-year-old woman noticed a left breast mass and underwent excisional biopsy. The excised mass measured 1.7 cm in diameter. Histologically, the tumor-like mass revealed irregular vascular channels with occasional thrombi and many papillary projections of fibrous stalks lined with a layer of flat endothelial cells. A small cavernous hemangioma was present adjacent to the lesion. Scanning electron microscopic observation revealed disorderly oriented thin and thick cords forming branches and meshworks in the lumina. The luminal wall and cords were covered with flat endothelial cells. Light and scanning electron microscopic differences between intravascular papillary endothelial hyperplasia and angiosarcoma are discussed.

Breast↗