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Biomedical subjects

K Nitta

Publications and source records attributed to K Nitta.

At least 307 records · Page 17Linked to original sources
PubMed1985

Responsiveness of cerebral vessels to changes of blood pressure and partial pressure of carbon dioxide after a transient period of cardiac arrest in dogs.

Post-ischemic cerebral hypoperfusion supposedly due to constriction of cerebral vessels is considered to be one of the most important factors limiting the recovery of the brain after cerebral ischemia. An experimental study on dogs was carried out to determine the changes in the responsiveness of cerebral vessel to the dilating effects of increase of arterial pressure (AP) and of CO2 inhalation after 3-6 min of cardiac arrest. Responsiveness was measured by the ratio of change in intracranial pressure (ICP) to change in AP (delta ICP/delta AP) and to change in PCO2 (delta ICP/delta PCO2), since in a bony cranium the changes in cerebral vessel diameter are reflected by instantaneous ICP change. delta ICP/delta AP following the administration of intravenous epinephrine was 33%, 43%, 36%, 37% and 16% of pre-ischemic value 1 h, 2 h, 3 h, 4 h and 5 h after cerebral ischemia, respectively. delta ICP/delta PCO2 following 10% CO2 inhalation was 13%, 32%, 55%, 50%, 70% and 75% of pre-ischemic value 1/2 h, 1 h, 2 h, 3 h, 4 h and 5 h after cerebral ischemia, respectively. Normal delta ICP/central venous pressure (delta CVP) was observed during the post-ischemic period, although statistical analysis was not done. From this we concluded: After 3-6 min of cardiac arrest, cerebral arteries constricted for more than 5 h during post-ischemic period. These arteries did not respond well to the dilating effects of increased arterial pressure or CO2 inhalation, but after 3 h their responses to CO2 inhalation returned to their pre-ischemic levels. The intracranial pressure became more or less dependent on CVP during post-ischemic period.

Animals↗
PubMed1985

Non-invasive estimation by cross sectional echocardiography of myocardial damage in cardiomyopathy.

Retrospective and prospective studies of high resolution cross sectional echocardiograms were undertaken in order to establish an ultrasonic method for the non-invasive estimation of degeneration and fibrosis of the endomyocardium in cases of cardiomyopathy. When the echocardiograms of the ventricular wall were compared with the histological specimens intense abnormal echoes were seen at the sites of myocardial degeneration and fibrosis of the ventricular wall. The abnormal echoes classified into five types: types I, II, III-1, III-2, and III-3. Type I and type III-1 echoes were the strongest followed by those of types II and III-2, and then those of type III-3. The intensity of the abnormal echoes was 5-20 decibels stronger than that from intact tissue and was closely related to the consistency and density of the diseased tissue. These findings strongly suggest that the boundary between degeneration or fibrosis and the intact normal myocardium was the source of the abnormal myocardial echoes and that the extent and the pattern of the distribution of the sites of degeneration and fibrosis in the myocardium were reflected in the echo patterns. Thus the tissue characteristics of the sites of degeneration or fibrosis of the myocardium may be determined non-invasively by measuring the echo intensity.

Adolescent↗
PubMed1985

[Mechanism of 67Ga uptake by an experimental abscess--permeability of plasma from blood vessels in abscessed tissue].

In the previous paper, we reported that 67Ga was accumulated in abscess and uptake rate of 67Ga in abscess increased with time after the injection of 67Ga-citrate. The present study was undertaken to elucidate the influence of blood flow on the accumulation of 67Ga in abscess. Five days after subcutaneous injection of 0.2 ml of turpentine to the rats, 131I-human serum albumin (HSA) was injected intravenously to the rats. At an appropriate time after the injection (10 min to 6 days), uptake rates of 131I-HSA in abscess and normal tissues were measured. Similarly, 51Cr-red blood cells (RBC) were injected intravenously to the above rats and the uptake rates of 51Cr-RBC were also measured. One, three, and 24 hours after injection of 131I-HSA, the uptake rates of 131I-HSA in abscess were 1.32 %dose/g, 1.84 %dose/g, and 0.82 %dose/g, respectively. However, the uptake rates of 51Cr-RBC in abscess was very small, and the value was 0.14 %dose/g at 24 hours after the injection. In the case of abscess, blood in the tissue fluid was very little, but the permeability of 131I-HSA from the blood vessel in the tissue was much larger than that of normal tissues. From these facts, it was deduced that the accelerated permeability caused the abscess accumulation of 67Ga.

Abscess↗
PubMed1985

The therapeutic effects of orally administered 5'-deoxy-5-fluorouridine, 1-(2-tetrahydrofuryl)-5-fluorouracil and 5-fluorouracil on experimental murine tumors.

The antitumor effects of three 5-fluorouracil-related compounds, 5'-deoxy-5-fluorouridine (5'-DFUR), 1-(2-tetrahydrofuryl)-5-fluorouracil (FT-207) and 5-fluorouracil (5-FU) itself, on several experimental murine tumors were compared after oral administration. 5'-DFUR showed strong antitumor activity against the solid type of four kinds of tumors tested with a wide range of effective doses, and also showed moderate antitumor activity against three kinds of solid tumors with a narrow range of effective doses. 5'-DFUR was effective against a few kinds of ascites tumors. In general, the antitumor activity of FT-207 was not very strong, with narrow ranges of effective doses under the present conditions. 5-FU showed strong toxicity but at lower doses its antitumor effectiveness was almost the same as that of FT-207. When the doses were divided into three and the divided dose was given orally three times a day for five consecutive days to mice bearing L1210 leukemia, this modality (with any of the three drugs) enhanced the ILS of the mice by two to three times in the case of the ascites type but not the solid type of L1210. The chemotherapeutic index in oral treatment of the solid type of tumors was higher for 5'-DFUR than for FT-207 or 5-FU. The minimum lethal doses in oral administration for five consecutive days were about 3, 1.5 and 0.5 mmol/kg/day for 5'-DFUR, FT-207 and 5-FU, respectively. In conclusion, 5'-DFUR appeared to have stronger antitumor activity and less toxicity than FT-207 and 5-FU, and it is therefore expected to be clinically useful.

Animals↗
PubMed1985

[Pulsed Doppler evaluation of left ventricular pressure and pressure difference in hypertrophic obstructive cardiomyopathy].

To assess the patho-physiological severity of hypertrophic obstructive cardiomyopathy (HOCM), the systolic pressure differences caused by the functional stenosis across the outflow tract of the left ventricle must be evaluated. The present study explored and proposed a non-invasive method predicting the pressure difference across the intraventricular obstruction and the pressure proximal to the obstruction by using pulsed Doppler technique, guided by simultaneous two-dimensional echocardiography. The ultrasonic equipment recently developed in our laboratory was used. It consisted of a 3.0 MHz pulsed ultrasonic transducer with a 4.4 KHz repetition rate and a mechanical sector scanner equipped with a single concave transducer 1.3 cm in diameter having a 70 mm radius of curvature. The sample volume was approximately 3 X 3 X 3 mm. Doppler signals obtained were subjected to a real-time analyzer with a fast Fourier transformer, and were simultaneously recorded on a thermal recorder as a spectral display together with an M-mode echocardiogram, lead II ECG, phonocardiogram and mechanocardiogram. Ten adults with HOCM were the subjects in the present study. For six of the 10, good pressure tracings were obtained. The pressure differences estimated by the maximum velocity as measured from the Doppler signals at the left ventricular (LV) outflow tract and the pressure gradients as obtained by cardiac catheterization were subjected to correlative analysis. Prior to investigating the pressure differences, the site and mechanism of the outflow obstruction in HOCM were studied in two cases using two-dimensional echocardiography in the longitudinal- and short-axis views. The obstruction was produced during systole by posteroinferior displacement of the hypertrophied interventricular septum and by abnormal anterosuperior movement of the hypertrophied, and elongated anterior or posterior papillary muscles. Thus, a concentric and centripetal narrowing was formed at the midportion of the outflow tract. In some cases, a bottle-shaped chamber was clearly observed in the apical area. Ultrasonic Doppler examinations were performed by the apical approach. Flow velocity patterns in the apical region or proximal to the obstruction had two peaks with a narrow spectrum in systole. At the distal portion or downstream the obstruction had a pattern with a narrow spectrum and a sharp single peak. To measure the maximum flow velocity, Doppler velocity patterns recorded immediately distal to the obstruction were used.(ABSTRACT TRUNCATED AT 400 WORDS)

Blood Flow Velocity↗
PubMed1985

Effect of forphenicinol, a small molecular immunomodifier, in combination with cyclophosphamide on growth of and immunity to syngeneic murine tumors.

Forphenicinol (FPL) is a low molecular immunomodifier derived from forphenicine, a microbial product found by Umezawa and co-workers. We studied the antitumor effect of FPL, cyclophosphamide (CY), and the combination of the two on several syngeneic murine tumors. The tumors used were mammary carcinoma, L1210 leukemia, B16 melanoma, Lewis lung carcinoma, and glioblastoma. A single ip injection of CY on Day 1 followed by eight consecutive daily oral doses of FPL beginning 6 days after tumor inoculation showed strong cooperation in curing syngeneic mammary carcinoma inoculated intradermally in C3H/HeN mice, most mice being cured of the tumor by the combination therapy and subsequently having acquired strong specific immunity. Treatment with FPL alone (either pre- or post-treatment) also significantly inhibited the growth of the mammary tumor. FPL and CY also showed cooperation in inhibiting the growth of L1210 leukemia transplanted intradermally into CDF1 (BALB/c X DBA/2) mice and markedly prolonged the survival time but FPL treatment alone had no effect. The FPL-CY treatment also affected Lewis lung carcinoma and glioblastoma in syngeneic C57BL/6 mice and produced therapeutic synergism. FPL alone significantly inhibited the growth of B16 melanoma in C57BL/6 mice as well as the syngeneic mammary carcinoma in C3H/HeN mice. These findings suggest that oral administration of FPL in combination with chemotherapeutic agents can be used for treating cancer without causing toxicity, because of the synergistic efficacy of the combination.

Adjuvants, Immunologic↗
PubMed1985

[A case of hemangiopericytoma in the pelvic retroperitoneum and review of literature of hemangiopericytoma in the retroperitoneal space in Japan].

Hemangiopericytoma is a rare capillary tumor that was first described and named by Stout and Murray in 1942. A case of hemangiopericytoma in the pelvic retroperitoneum is reported. The patient, a 57 year old man, was admitted because of dysuria. He underwent extirpation of the tumor with the rectum by low anterior resection. The pathological diagnosis was malignant hemangiopericytoma, and Adriamycin was administered to prevent recurrence or metastasis. He has been free from any recurrence or metastasis for the last eight months. Twenty cases of hemangiopericytoma in the retroperitoneum including our case, were collected from Japanese literature and reviews. Hemangiopericytoma, especially in the retroperitoneal space, should be regarded as a highly malignant tumor. Early aggressive therapy and long term follow up are recommended because the tumor characteristically produces late local recurrence and metastasis.

Doxorubicin↗
PubMed1984

Studies on three kinds of lectins from Xenopus laevis skin.

Among skin extracts of various frogs, lectin activity was found only in fractions prepared from Xenopus laevis skin. 3 skin lectins have been separated. Among these, the lectin designated S2-Dlc was isolated in a homogeneous state and showed a preferential agglutination of Ehrlich and S-180 ascites tumor cells; other tumor cells and human erythrocytes were not agglutinated. The lectin-dependent agglutination was inhibited by D-fucose, L-arabinose, D-galactose, lactose and lactulose. The sugar specificity of this lectin is similar to that of the lectin from Xenopus laevis eggs which agglutinates Ehrlich and S-180 ascites cells.

Animals↗
PubMed1984

Conformational studies on rat alpha-lactalbumin.

The reversible unfolding of rat alpha-lactalbumin, which, in contrast to other alpha-lactalbumins, has a 17-amino-acid extension at the carboxyl terminus and a carbohydrate unit at Asn-45, was studied by circular dichroism between 193 and 310 nm as a function of pH, heat and guanidine hydrochloride ( GdnHCl ). The native structure of rat alpha-lactalbumin was similar to that of bovine alpha-lactalbumin. Acidification changes rat alpha-lactalbumin to a state similar to the 'A state' of bovine alpha- lactalbumin . The heat-reduced unfolding of the tertiary structure of rat alpha-lactalbumin is highly cooperative. The GdnHCl -induced unfolding of rat alpha-lactalbumin could not be expressed by a two-state mechanism as in the case of bovine alpha-lactalbumin. However, the midpoints of transitions suggested lower stabilities of secondary and tertiary structures in rat alpha-lactalbumin than in bovine alpha-lactalbumin consistent with the differences in the local structure between rat and bovine alpha-lactalbumins.

Animals↗
PubMed1984

Separation of macrophages from mouse peritoneal exudate cells with substrata coated with chemically modified collagens.

A cell-separation technique was designed on the basis of specific interaction between macrophages and chemically modified collagens in the presence of serum. When unseparated mouse peritoneal exudate cells containing approximately 50% macrophages and 50% lymphocytes were incubated in dishes coated with unmodified and chemically modified collagens, only macrophages adhered more rapidly and in greater numbers to succinylated and methylated collagen than to unmodified collagen. The adherent macrophages could be easily detached from the substrata by divalent cation chelating agents. The purity and recovery of macrophages separated by this method were approximately 92-94% and 41-48%, respectively.

Animals↗
PubMed1984

67Ga-binding substances in abscess and normal tissues.

Abscess-induced animals and normal animals were treated with 67Ga-citrate. Abscess, kidney, heart, lung, and spleen were excised and homogenized. After removal of the nuclear fraction, each of these homogenates was digested with protease. After digestion, the supernatants of the reaction mixtures were applied to a Sephadex G-100 column. Resultant eluates were analyzed for radioactivity, protein, uronic acids, and sialic acids. Sodium sulfate-35S was administered to animals that were then treated by the same procedure as that followed for animals treated with 67Ga-citrate. In abscess, kidney, lung, heart, and spleen, sizeable amounts of 67Ga had been bound to the sulfated acid mucopolysaccharides with molecular weights of about 10,000, and to the sulfated acid mucopolysaccharides, a species whose molecular weights exceeded 40,000. Based on the results presented here, it is clear that 67Ga-binding substances in abscess and also in the above four organs are sulfated acid mucopolysaccharides.

Abscess↗
PubMed1984

Survey of CELSS concepts and preliminary research in Japan.

Many agricultural and other experiments relating to the development of a Controlled Ecological Life Support System (CELSS) were proposed by scientists throughout Japan in the fall of 1982. To develop concrete experimental concepts from these proposals, the engineering feasibility of each proposal was investigated by a CELSS experiment concept study group under the support of the National Aerospace Laboratory. The conclusions of the group were described in two documents. Originally, the study group did not clearly define necessary missions leading to the goal of an operational CELSS for spaceflight. Therefore, the CELSS experiment concept study group met again to clarify the goals of CELSS and to determine three phases to achieve the goals. The resulting phases, or missions, and preliminary proposals and studies needed to develop a CELSS are described herein.

Animals↗
PubMed1984

Cerebral blood flow during conventional, new and open-chest cardio-pulmonary resuscitation in dogs.

The following parameters were monitored simultaneously in 15 dogs, in order to evaluate the efficacy of conventional CPR (C-CPR), new CPR (N-CPR), and open-chest CPR (O-CPR) on cerebral perfusion: arterial blood pressure (BP), central venous pressure (CVP), intrathoracic airway pressure, blood flow in carotid artery, intracranial pressure (ICP), sagittal sinus blood flow (sinus BF) and pressure (sinus P), and blood flow in cerebral cortex (cortical BF). The sinus blood flow was measured by the direct-method and with a cannulating electromagnetic flowmeter. The cortical blood flow was measured with a termocouple tissue flowmeter. Intracranial pressure was obtained by measuring subarachnoid cerebrospinal fluid pressure. Ventricular fibrillation was induced electrically. Chest compression and ventilation were always done manually in all cardiopulmonary resuscitation. The mean blood pressures during C-CPR, N-CPR and O-CPR were 52, 68 and 95 mmHg, respectively, and mean carotid blood flows per stroke were 36, 71 and 131% of the control values, respectively. The intracranial pressures were 30, 42 and 36 mmHg, respectively, giving the calculated cerebral perfusion pressures (BP-ICP) of 22, 27 and 60 mmHg, respectively. This should have been reflected in cerebral blood flow. Sinus blood flows/min were 18, 18 and 42%, and sinus blood flows per stroke were 55, 45 and 127% of control values, respectively; the differences between C-CPR and N-CPR were not significant. This was also true for cortical blood flow. From this we conclude that, firstly, N-CPR is not significantly better than C-CPR in cerebral perfusion because of its accompanying high intracranial pressure, secondly, O-CPR is far superior to the other two methods in respect of cerebral perfusion.

Animals↗