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Biomedical subjects

K Asano

Publications and source records attributed to K Asano.

At least 181 records · Page 10Linked to original sources
PubMed1997

[Long-term observation of sensorineural hearing-impaired children with hearing aids].

In the long-term observation (9-22 years) of 45 hearing-impaired children, using our own "Hearing Test Progress Table", 36(80.0%) showed fluctuation of the hearing threshold. Twenty-nine of the 36 patients had acute progression of hearing loss. Three peaks of onset of the acute loss were observed: at age 6, 10, 16 years in girls, 7, 11 and 16 years in boys. Twenty-three of the 45 (51.1%) have been able to maintain their good thresholds throughout these periods, with 14 cases of hearing loss restored by our successful treatment of acute sensorineural hearing losses (1-6 times). Twenty-two of the 45 children (48.9%) could not maintain their initial thresholds: gradual hearing deterioration in 7 of the 22, and acute hearing loss (1-10 times) in the remaining 15 cases. Although these 15 patients could not maintain their initial hearing thresholds until the end of the observation period, active treatments for their acute losses were successful in the early period, and almost all patients were able to maintain their initial hearing thresholds until graduation from elementary school. Our "Hearing Test Progress Table" is based on the results of pure tone audiometry for each frequency on every audiometry test. The management (including guidance and treatment) using the table is very effective.

Child↗
PubMed1997

[En bloc resection of the temporal bone for middle ear carcinoma extending to the cranial base].

En bloc resection of the temporal bone for squamous cell carcinoma of the middle ear was performed by the postauricular transtemporal and retromastoid approaches. The patient was a 70-year-old woman whose tumor extended to the middle and posterior cranial fossae. Temporal and retromastoid craniotomies were carried out, then the temporal dura and the cerebellar dura, and the transverse and sigmoid sinuses were exposed. The temporal dura and the cerebellar dura were opened, and the transverse sinus was ligated at the junction with the sigmoid sinus. After that, the tentorial dura was incised, the incision extending anteriorly to the middle cranial fossa and transecting the superior petrosal sinus. Consequently, a wide view into the middle and the posterior cranial fossae was obtained. In the posterior fossa, cranial nerves VII and VIII were divided. On the other hand, nerves IX, X and XI were preserved at the dural incision on the posterior surface of the temporal bone. Subsequently, in the area of the carotid canal, the temporal bone was drilled toward the medial side of the internal auditory canal and also posteriorly down to the jugular bulb. At this stage, the temporal bone and the soft tissue attachments, such as the middle and posterior cranial fossa dura, and the sigmoid sinus, were separated from the pyramidal apex and the clivus. The dural defect was repaired with a free pericranial graft. A rectus abdominis muscle flap was transferred to reconstruct the defect of the skull base resulting from the temporal bone resection. Postoperative complications like CSF leakage, meningitis and lower cranial nerve damage, were not seen after the treatment. The patient has shown no evidence of recurrence for the 28 months since the surgical treatment, and has not complained of any problems with swallowing or conducting conversations in daily life. With the contribution of recent developments in skull base and reconstruction surgery, more aggressive en bloc resection of the temporal bone can be carried out on patients with advanced middle ear carcinoma. These developments will also make it possible for patients whose prognosis was previously thought to be poor to have a chance for a cure.

Aged↗
PubMed1997

[Study of the effects of treatment with interferon for the advanced renal cell carcinoma based upon the survival rate].

BACKGROUND: There is no consistent acknowledgment with the effects of the prolongation of survival for the advanced renal cell carcinoma (RCC) treated with interferon (IFN). Therefore, we tried to study on the effects of such prolongation of survival for the advanced RCC through the comparative analysis between the patients treated with IFN and the patients treated with other treatment modalities in the past years. PATIENTS AND METHODS: We differentiated the patients treated with IFN (recurrent patients after nephrectomy as Group I, and patients with stage 4B as Group II) from the patients treated with other modalities (recurrent patients after nephrectomy as Group III, and patients with stage 4B and Group IV). We compared the survival rate between the two groups (Groups I vs III, and Groups II vs IV). RESULTS: Regarding the various factors affecting prognosis of RCC, no significant difference was observed among these groups. 1) There observed a significantly favorable survival rate in the Group I compared with the Group III, and the same result was observed in the Group II compared with the Group IV. 2) In the patients with performance status (P.S.) 0 and low grade, there observed a significantly favourable survival rate in the Group I compared with the Group III, and the same result was observed in the Group II compared with the Group IV. Furthermore, in the patients with low stage, the Group I showed a significantly favourable survival rate compared with the Group III. 3) In the study on the number of metastatic organs (1, 2 and 3 organs or more), there observed a significantly favourable survival rate in the Group I compared with the Group III for all numbers of the metastatic organs. The same result was observed in the group II compared with the Group IV, except for the patient with 3 organs or more. Regarding the operative procedures for the metastatic side, the patients who did not receive the operative procedures showed a significantly favourable survival rate in the Group I compared with the Group III. The same result was observed in the Group II compared with the Group IV. 4) As to the survival rate based upon the response rate, only the patients with no change (N.C.) showed a significantly favourable survival rate in the Group I compared with the Group III. The same result was observed in the Group II compared with the Group IV. CONCLUSION: We conclude that the treatment with IFN for the advanced RCC would much contribute to the prolongation of the survival in comparison with the previous patients who received other treatments.

Adolescent↗
PubMed1997

[A case of mediastinal liposarcoma surgically removed by bilateral thoracotomy].

A rare case of mediastinal liposarcoma was experienced at our institute. A 64-year-old male patient was accidentally found by chest X-ray photo. The tumor was so gigantic and seemed to involve the descending aorta, therefore, it was removed through bilateral thoracotomy. It was well encapsulated and its malignancy resides in that of low grade to be completely removed. The patient is expected to acquire long term survival.

Humans↗
PubMed1997

Relation of sympathetic activation to ventilation in man at 4300 m altitude.

BACKGROUND: The sympathetic nervous activity increases at high altitude but is not maximal initially when hypoxemia is most severe. HYPOTHESIS: The sympathetic activation would correlate better to the ventilatory response to chronic hypoxia than to the severity of hypoxia per se. METHODS: Eleven healthy male volunteers (27 +/- 1 yr) had measurements from the abdominal aorta of pressure, catecholamines, and blood gases at sea level, on arrival at 4300 m, and after 21 d of residence. Additionally, we measured 24-h urinary catecholamine excretion at sea level and each day at altitude, and made serial measurements of resting ventilatory parameters. RESULTS: Arterial norepinephrine (NE) concentrations on arrival at 4300 m were little changed from sea level, but were increased following acclimatization at 21 d. Arterial oxygenation was decreased on arrival, but improved with acclimatization. Arterial epinephrine (E) concentrations were increased on arrival, and returned to an intermediate level by 21 d. The urinary NE excretion was increased along with the increase in VE (p < 0.01) and the fall in end-tidal PCO2 (p < 0.001), but not with the decrease in end-tidal PO2 during the sojourn at 4300 m. Excretion of E did not relate to any ventilatory parameters. Propranolol (240 mg.d-1), which was given to 6 of 11 subjects, did not affect any relationships. CONCLUSION: The sympathetic activation was related to the ventilatory response but not to measures of hypoxemia at 4300 m. We conclude that factors related to ventilatory acclimatization, possibly increased chemoreceptor activity, contribute to the development of sympathetic activation at high-altitude.

Acclimatization↗
PubMed1997

[Effect on 5'-deoxy-5-fluorouridine (5'-DFUR) of pyrimidine nucleoside phosphorylase (PyNPase), matrix metalloprotease and serum IAP values. Hokuriku Colorectal Cancer Chemotherapy Study Group].

PyNPase activity, MMPs activity and serum IAP values were measured in tumor tissues from colorectal cancer patients who had been divided into two groups, one given preoperative 5'-DFUR and the controls. PyNPase activity of the preoperative administration group was approximately equivalent to that of the controls. In the control group, correlations were assessed between PyNPase activity and activities of MMP1 and MMP3. To assess the effect of 5'-DFUR on the activity of MMPs, we divided patients into two groups, a high and a low PyNPase activity group. Although there was no correlation with MMPs activity of the preoperative administration group and the control group in the low PyNPase activity group, the activities of MMP1 and MMP9 of the control group were significantly higher in the high PyNPase activity group. Moreover, the serum IAP value of the administration group was significantly lower than that of the control group. These results indicated that PyNPase activity was thus suggested to be somehow related to MMPs activity and serum IAP values.

Adult↗
PubMed1997

[A case of giant cell-rich gliosarcoma].

We report a case of gliosarcoma with numerous giant cells resembling ganglion cells and having clear nucleoli. A 75-year woman was admitted to our hospital suffering from progressive left hemiparesis and ambulatory disturbance of one week's duration. CT and MRI studies showed ring enhancement on a clear margin mass in the right parieto-occipital lobe. The mass was totally removed macroscopically. Her left hemiparesis had improved and self walk came to be possible. But the tumor was regrowthed during next two months and she died for three months and a week. The gross and microscopic appearances of the tumors showed the double structure. The surface of the tumor was well enhanced and consisted of soft, gray, and easily bleeding tissue. The central core, however, was poorly enhanced and consisted of hard, yellow, non-bleeding tissue. Macroscopically, the central area included numerous giant ganglion-like cells which were negative for GFAP but positive for EMA in the cytoplasm. These giant cells had abundant collagen fibers and were surrounded by such fibers. Microscopic findings of the surrounding area included numerous spindle shaped cells which were positive for GFAP and vimentin. The origins of giant cells or tumor tissues have long been discussed, but no consensus has yet been obtained. Therefore, we speculated as to the origin in our patient based on immunohistochemical study and the findings of electronmicroscopy. We concluded, in sharp contrast to the old theory of one origin, epithelial tissue of a hamartomatous nature existed initially, followed by the growth of malignant tissue of a reactive astrocytic tumor with a sarcomatous component.

Aged↗
PubMed1996

Distribution of thromboxane A2 receptor mRNA along the mouse nephron segments.

Thromboxane A2 (TXA2) receptor mRNA was semi-quantitated in microdissected mouse nephron segments by reverse transcription-polymerase chain reaction (RT-PCR). TXA2 receptor mRNA was most abundantly expressed in the glomerulus, followed by the distal convoluted tubule > proximal tubule, thick ascending limb of Henle, and outer medullary collecting duct. These results suggest the potential physiological roles of TXA2 in the entire renal tubule as well as in the glomerulus.

Actins↗
PubMed1996

Distribution of platelet activating factor receptor mRNA along the rat nephron segments.

Platelet activating factor (PAF) receptor mRNA was semi-quantitated in microdissected rat nephron segments by the reverse transcription-polymerase chain reaction (RT-PCR). PCR primers were designed from two alternative splicing isoforms of rat PAF receptor cDNA; a homologue of human leukocyte PAF receptor cDNA (p172) and the other with a unique sequence in the 5'-noncoding region upstream of the splice acceptor site (p18). Only the expression of mRNA corresponding to p172 was detectable, which was most abundant in the glomerulus, followed in order by: proximal convoluted tubule > proximal straight tubule > outer medullary and cortical collecting duct, distal convoluted tubule > thick ascending limb of Henle's loop. These results suggest the potential physiological roles of PAF in the entire renal tubule as well as in the glomerulus.

Alternative Splicing↗
PubMed1996

Superoxide dismutase derivative prevents oxidative damage in liver and kidney of rats induced by exhausting exercise.

To prevent oxidative tissue damage induced by strenuous exercise in the liver and kidney superoxide dismutase derivative (SM-SOD), which circulated bound to albumin with a half-life of 6 h, was injected intraperitoneally into rats. Exhausting treadmill running caused a significant increase in the activities of xanthine oxidase (XO), and glutathione peroxidase (GPX) in addition to concentrations of thiobarbituric acid-reactive substances (TBARS) in hepatic tissue immediately after running. There was a definite increase in the immunoreactive content of mitochondrial superoxide dismutase (Mn-SOD) 1 day after the running. Meanwhile, the TBARS concentration in the kidney was markedly elevated 3 days after running. The activities of GPX, and catalase in the kidney increased significantly immediately and on days 1 and 3 following the test. The immunoreactive content of Mn-SOD also increased 1 day after running. The exercise induced no significant changes in immunoreactive Cu, Zn-SOD content in either tissue. The administration of SM-SOD provided effective protection against lipid peroxidation, and significantly attenuated the alterations in XO and all the anti-oxidant enzymes, measured. In summary, the present data would suggest that exhausting exercise may induce XO-derived oxidative damage in the liver, while the increase in lipid peroxidation in the kidney might be the result of washout-dependent accumulation of peroxidised metabolites. We found that the administration of SM-SOD provided excellent protection against exercise-induced oxidative stress in both liver and kidney.

Animals↗
PubMed1996

Comparison of muscle force, muscle endurance, and electromyogram activity during an expedition at high altitude.

Handgrip force (HF), maximal pinch force (MF), muscle endurance (ME), and the median power frequency (MdPF) of the activity shown in the electromyogram (EMG) were studied at various altitudes in eight normal healthy subjects. MF and ME were measured between the index finger and thumb, and all measurements were obtained at altitudes ranging from 610 to 4860 m during an expedition in the Qinghai Plateau in China. With the change in altitude HF, ME, and MF showed no significant change. Compared to the MdPF at 2260 m on ascent, the MdPF at other altitudes showed a significant decrease (P < 0.01). Thus, we conclude that muscle performance (HF, MF, and ME) was not affected by the environment at high altitude. However, MdPF was affected and the mean MdPF at 610 m after the expedition did not recover to initial values of MdPF. We suggest these results may have been affected by fatigue and chronic exposure to the hypobaric hypoxic environment, since the members of the expedition party expressed feelings of sluggishness and fatigue after the expedition.

Acclimatization↗
PubMed1996

31P nuclear magnetic resonance study on changes in phosphocreatine and the intracellular pH in rat skeletal muscle during exercise at various inspired oxygen contents.

We measured ATP, phosphocreatine (PCr), inorganic phosphate (Pi), and the intracellular pH in rat hindlimb muscles during submaximal isometric exercise with various O2 deliveries using 31P nuclear magnetic resonance spectroscopy (31P NMR) to evaluate changes in energy metabolism in relation to O2 availability. Delivery of O2 to muscles was altered by controlling the fractional concentration of inspired oxygen (F1O2) at 0.50, 0.28, 0.21, 0.11 and 0.08 with monitoring partial pressure of oxygen and carbon dioxide, and bicarbonate at the femoral artery. The steady-state ratio of PCr: (PCr + Pi) during exercise decreased as a function of F1O2 even at 0.21. Significant acidification of the intracellular pH during exercise occurred at 0.08 F1O2. Change in the PCr: (PCr + Pi) ratio demonstrated that the oxidative capacity, i.e. the maximal rate of the oxidative phosphorylation reaction, in muscle was not limited by O2 delivery at 0.50 F1O2, but was significantly limited at 0.21 F1O2 or below. Change in the intracellular pH at 0.08 F1O2 could be interpreted as an increase in lactate, suggesting activation of glycolysis. Correlation between the PCr: (PCr + Pi) ratio and the intracellular pH revealed the existence of a critical PCr: (PCr + Pi) ratio and pH for glycolysis activation at around 0.4 and 6.7, respectively.

Animals↗
PubMed1996

Influence of deoxyspergualin on mononuclear phagocytic system in mice.

The influence of deoxyspergualin (DSG) on mononuclear phagocytic system was examined in BALB/c mice. DSG did not influence on both the organ distribution of sheep red blood cells (SRBC) and blood clearance of colloidal carbon when the agent was administered intraperitoneally into mice at doses of 5.0 and 10.0 mg/kg for six consecutive days before antigen. Hemagglutination titers in experimental and control mice did not differ significantly when 10.0 mg/kg of DSG was given six times before SRBC injection. However, when administered during the course of the response (days 0 to 5) DSG (5.0 mg/kg/day) markedly suppressed antibody formation.

Animals↗
PubMed1996

Inhibitory action of deoxyspergualin on effector/memory T cell generation during Hymenolepis nana infection in mice.

The effects of deoxyspergualin (DSG), a newly developed immunosuppressive agent, on protective immunity to Hymenolepis nana reinfection were examined in BALB/c mice. Administration of DSG at daily doses of 10.0 mg/kg to 30.0 mg/kg (but not 5.0 mg/kg) caused suppression of protective immunity when the agent was injected intraperitoneally during the induction phase of the immunity. In contrast, daily administration of 30.0 mg/kg DSG, during effector phase, could not suppress protective immunity. DSG inhibited endogenous interferon-gamma production in mesenteric lymph nodes induced by H. nana challenge infection, when the agent was injected intraperitoneally at a daily dose of 10.0 mg/kg during the induction phase of immunity. Delayed type hypersensitivity (DTH) local transfer analysis revealed that administration of DSG at 10.0 mg/kg/day into donor mice during induction phase of immunity inhibited generation of effector/memory cells that mediate DTH to H. nana egg antigen. However, DSG could not inhibit DTH effector cell activation when cells prepared from H. nana-infected, saline-injected mice were transferred into recipient treated with 10.0 mg/kg DSG. Administration of DSG at a dose of 10.0 mg/kg daily for 5 days produced large DNA fragments in mesenteric lymph node (MLN) cells. These results strongly suggest that DSG suppresses generation of effector/memory cells by apoptotic cell death but cannot suppress lymphocyte activation in vivo.

Animals↗
PubMed1996

Long-term outcome of patients who received Starr-Edwards valves between 1965 and 1977.

To determine the risk factors relating to long-term outcomes of the Starr-Edwards ball valve, data from 150 patients (75 males, 75 females; age range 9-67 years); who underwent valve replacement (44 aortic, 106 mitral) between 1965 and 1977 at Niigata University were reviewed retrospectively. Valve models 6120/6320 and 1260/2320 were mainly used in mitral and aortic positions, respectively. The cumulative follow-up period was 2227.4 patient-years. Using the Kaplan-Meier life-table method, actuarial probability of freedom from valve-related mortality, morbidity and thromboembolism were analysed. Thirteen patients died from various causes during hospitalization. Some 80 patients suffered 97 instances of valve-related morbidity and 58 died during follow-up (up to 28 years). Patient age > 50 years affected the actuarial probability of freedom from valve-related mortality in the entire group (P < 0.05). Valve type and the year of operation were discriminative predictors of thromboembolic complications in the entire group (both P < 0.05) and in the mitral valve replacement group (P < 0.01 and P < 0.001). However, only the year of operation affected the actuarial probability of freedom from all valve-related morbidity in the entire group and in the mitral valve replacement group (both P < 0.05). Univariate analysis revealed that age at surgery, valve type, and the year of operation were related to late postoperative outcome in patients who received a Starr-Edwards ball valve between 1965 and 1977.

Actuarial Analysis↗
PubMed1996

Conservation and diversity in the structure of translation initiation factor EIF3 from humans and yeast.

Initiation factor eIF3 plays a central role in the initiation pathway, influencing ribosome association, ternary complex binding to 40S subunits, and mRNA binding, in part through an interaction with eIF4F. We are attempting to clone and sequence DNAs encoding the subunits of this complex factor. Mammalian eIF3 comprises 10 subunits; full-length human cDNAs have been cloned for eight of these, and partial clones are in hand for the remaining two. Yeast eIF3 comprises at least seven subunits, with six of the seven genes identified and sequenced. Comparison of eIF3 subunit sequences between human and yeast reveals an unexpectedly large diversity of structure. Surprisingly, comparisons with other sequences in the data base suggest that some of the eIF3 subunits may have functions apart from the eIF3 complex. Work is in progress to use the cloned DNAs as tools for elucidating the structure of eIF3 and its interactions with other initiation factors.

Animals↗