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Biomedical subjects

K Chin

Publications and source records attributed to K Chin.

At least 91 records · Page 5Linked to original sources
PubMed1996

Inhibitory effect of an intellectual task on breathing after voluntary hyperventilation.

We investigated the effects of an intellectual task on posthyperventilation (PHV) breathing by using a video game. Eight normal subjects were placed in a supine positions. The game task by itself led to increase ventilation compared with the control tasks via an increase in the average inspiratory flow rate (P < 0.01) and the respiratory frequency (P < 0.001). After hypocapnic voluntary hyperventilation (VHV), the task led to a decrease in the 1-min PHV breathing level compared with the control tasks after VHV [after VHV, first 60 s average minute ventilation while watching television and while playing a video game are 5.54 +/- 2.91 (SD) and 2.05 +/- 1.40 l/min, respectively; P < 0.01]. Only one subject showed PHV apnea for at least 10 s during the control protocol, whereas seven of the same eight subjects showed PHV apnea while performing the task. After isocapnic VHV, the task still led to a decrease in PHV breathing compared with the control tasks. However, this decrease was smaller than in the hypocapnic studies and was only significant during the first 15 s of recovery. These results suggest that increased activity in the higher centers of the central nervous system has an inhibitory effect on PHV breathing at a time when the effects of short-term potentiation after VHV, hypocapnia, and perhaps other mechanisms would be expected to be acting on breathing.

Adult↗
PubMed1996

Prevalence of severity of hypoxemia following clinical voluntary hyperventilation.

The voluntary hyperventilation (VHV) test is used in many clinical examinations. However, arterial hypoxemia following a clinical VHV test is not a well-studied phenomenon. We analyzed the arterial blood gases (ABGs) of 61 patients during a VHV test. The ABG were taken prior to (PaO2-Prior), immediately following (PaO2-Immediate), and 5 min after (PaO2-After) the VHV test. The patients' average PaO2 rose significantly (p < 0.0001) from the PaO2-Prior (88 +/- 8 mm Hg; mean +/- SD) to the PaO2-Immediate (118 +/- 13 mm Hg) and then dropped significantly (p < 0.0001) to the PaO2-After (74 +/- 16 mm Hg). Two of the 20 patients who experienced an angina pectoris attack (AP(+)) following the VHV test showed severe arterial hypoxemia (PaO2-After < 60 mm Hg), whereas 9 of the 41 patients who did not experience an angina pectoris attack (AP(-)) showed a PaO2-After < 60 mm Hg. The PaO2-After did not correlate with the PaO2-Prior. The decrease in the PaO2-Prior to After did not correlate significantly with the left ventricular ejection fraction rate (n = 58, r = 0.18, not significant). However, the decrease in the PaO2-Prior to After correlated well with the degree of recovery of the PaCO2 following the VHV test (r = -0.69, p < 0.0001). The age, gender ratio, changes in arterial blood gases, number of patients who experienced PaO2-After < 60 mm Hg, and left-ventricular ejection fraction rate were not significantly different between the AP(-) and AP(+) groups. Posthyperventilation hypoxemia developed frequently following the VHV test during coronary angiography. Although this arterial hypoxemia was not directly correlated with the occurrence of AP attacks following VHV in this study, continuous SaO2 monitoring is recommended whenever a VHV test is used as a diagnostic technique to avoid the potentially deleterious effects of arterial hypoxemia.

Arteries↗
PubMed1996

Effects of NCPAP therapy on fibrinogen levels in obstructive sleep apnea syndrome.

In patients with obstructive sleep apnea syndrome (OSAS), the blood coagulation system may contribute to an increased risk of cardiovascular events, which occur most frequently in the morning. Nasal continuous positive airway pressure (NCPAP) treatment can improve the mortality of patients with OSAS. We measured the plasma fibrinogen concentration, which is an independent risk factor for cardiovascular events, in the afternoon (3:30 P.M.) and the next morning upon awakening (8:30 A.M.) in 11 patients with OSAS (apnea and hypopnea index > 20) before and after NCPAP therapy. We also measured the hematocrit, the C-reactive protein, and the total plasma protein at the same time. The plasma fibrinogen and hematocrit levels in the morning (298 +/- 16 mg/dl and 48.5 +/- 1.5%, mean +/- SEM) were significantly higher than on the previous afternoon (275 +/- 14 mg/dl and 46.6 +/- 1.3%) (fibrinogen, p < 0.02; hematocrit, p < 0.005). The whole blood viscosity (WBV) at a shear rate of 208 inverse seconds, which can be predicted based on the hematocrit and total plasma protein, was also significantly higher in the morning (4.98 +/- 0.20/s) than in the afternoon (4.73 +/- 0.17/s) (p < 0.005). These increases in the plasma fibrinogen concentration and the WBV in the morning disappeared after NCPAP treatment. The attenuation of morning increases in the plasma fibrinogen concentration and WBV induced by NCPAP treatment may contribute to an overall improvement in the mortality from cardiovascular events in patients with OSAS.

Adult↗
PubMed1996

Relationship between dyspnea in daily life and psycho-physiologic state in patients with chronic obstructive pulmonary disease during long-term domiciliary oxygen therapy.

We examined the relationships among dyspnea ratings in daily life, the physiologic state, and anxiety and depression of fifty-two patients with chronic obstructive disease (COPD) during long-term domiciliary oxygen therapy (LTOT). Clinical ratings of dyspnea were assessed by the visual-analog scale (VAS) during eight types of basic behavior in indoor daily life. Analysis of the physiologic state included forced expiratory volume in 1 second (FEV1.0), and arterial blood gas (PaO2, PaCO2) at rest while breathing room air. The hospital anxiety and depression (HAD) scale, which consists of 14 questions, was used to assess the degree of anxiety (HAD-A) and depression (HAD-D). The mean age of the patients was 69.5 +/- 10.8 year (SD), and the duration of LTOT was 944 +/- 739 days. The mean values were 0.77 +/- 0.45 L for FEV1.0, 57.7 +/- 7.4 Torr for PaO2, and 47.4 +/- 8.1 Torr for PaCO2. FEV1.0 was correlated with PaCO2(r = -0.548, p < 0.0001), but it was not correlated with PaO2. High correlation was noted between HAD-A and HAD-D (r = 0.693, P < 0.0001), whereas correlation was not noted between HAD and the physiologic state. VAS was significantly correlated with FEV1.0 (r = 0.320, p < 0.05), as well as with HAD-A (r = 0.358, p < 0.01) and HAD-D (r = 0.444, p < 0.01). Dyspnea ratings were found to be influenced by anxiety and the depression state, and also by the degree of flow limitation in patients with COPD during LTOT. In contrast, the physiologic state scarcely influenced the anxiety and depression state. Thus, psychotherapy may play an important role in the reduction of dyspnea sensation, which is an important determinant of quality of life.

Activities of Daily Living↗
PubMed1996

Validity of a random noise oscillation and body box system for the measurement of the respiratory impedance of small animals.

The accuracy and validity of a body box system which was developed for the measurement of airway and chest wall impedance in small animals such as canines was evaluated. Input impedance was calibrated using a resistance tube and the mouth flow sensing system was designed to be as symmetrical as possible such that the minimal common mode rejection ratio (CMRR) from 10 to 40 Hz was greater than 60 dB. The validity of this system using the resistance tube and inertant models indicated that the average error ratio for the input impedance and for the flow transfer function between the mouth and chest flow was within 3 and 0.5%, respectively. The location of the box pressure port near to the oscillatory flow inlet was shown to potentially give rise to errors in the measurement of the flow transfer factor due to the direct effects of the inflow. A distance of 60 cm was adopted in the present system, which proved to be sufficient to avoid this effect. It was concluded that the body box system which is described for small animals in the present study is appropriate for obtaining separate and accurate airway and tissue impedance data.

Airway Resistance↗
PubMed1996

Chest flow during the initial inspiratory phase (V0.1) in pulmonary diseased patients.

We measured the chest flow 0.1 s after the onset of the inspiratory phase (V0.1) in patients with chronic pulmonary emphysema (CPE: n = 5), interstitial pneumonitis (IP: n = 5) and normal subjects (Nor: n = 5). The subjects sat in a body box and breathed air from outside of the body box. V0.1 was measured during rest and during maximal breathing (V0.1-rest, V0.1-max) and then these results were compared with P0.1 (P0.1 rest, P0.1-max) values. V0.1-rest was not significantly different between the three groups (Nor: 0.25 +/- 0.10, CPE: 0.27 +/- 0.06, IP: 0.26 +/- 0.06, l/s), whereas the P0.1-rest in IP patients was significantly greater than in normal subjects (Nor: 1.98 +/- 0.61, CPE: 3.00 +/- 0.80, IP: 3.60 +/- 0.68 hPa; P < 0.05 compared with normal). The V0.1-max in CPE and IP patients was significantly lower than in normal subjects (Nor: 3.66 +/- 1.16, CPE: 0.82 +/- 0.25, IP: 1.02 +/- 0.21 l/s, P < 0.05 compared with normal subjects (Nor: 3.66 +/- 1.16, CPE: 0.82 +/- 0.25, IP: 1.02 +/- 0.21 l/s, P < 0.05 compared with normal), whereas P0.1-max in IP patients was not significantly different with in normal subjects (Nor: 33.2 +/- 10.2, CPE: 9.8 +/- 3.7, IP: 19.5 +/- 3.4 hPa, P < 0.05 compared with normal, P < 0.05 compared with CPE). A simulation of the influence of the mechanical properties of the respiratory system on V0.1 and P0.1 using the Runge-Kutta method suggested that V0.1 was negatively affected by airway resistance but positively affected by chest wall and lung compliance. In contrast, the influence of respiratory mechanics on P0.1 was much less than on the V0.1, except for highly decreased lung compliance. In CPE patients, it was suspected that mechanical disorders might not simply be the determining factors of V0.1-max, but that limitations of the neuro-muscular drive due to chest wall deformity may also play a definitive role in the smaller V0.1-max. In contrast, it may be inferred that IP patients had to exert greater inspiratory effort as compared with the other two groups in order to maintain a similar V0.1-rest because of the increased airway resistance and decreased tissue compliance; thus these abnormal mechanical properties suppress the increase in the V0.1-max. It may be concluded that V0.1 is a good index of chest wall acceleration, which is determined by both the neuro-muscular drive and the mechanics of the respiratory system.

Aged↗
PubMed1996

[Outcome of long-term nasal intermittent positive pressure ventilation in 41 patients with hypercapnic respiratory failure].

Nasal intermittent positive pressure ventilation (NIPPV) is widely used in domiciliary treatment of chronic ventilatory disorders. The outcomes of long-term NIPPV were analyzed in 41 patients with hypercapnic respiratory failure due to pulmonary tuberculosis sequelae (PTS; n = 17), neuromuscular disease (NMD; n = 8), kyphoscoliosis (KS; n = 7), chronic obstructive pulmonary disease (COPD; n = 6), and miscellaneous diseases (n = 3). Twenty-seven patients with chronic conditions but without acute exacerbations began receiving NIPPV, and fourteen patients began receiving NIPPV after an acute exacerbation. Outcome measures included the probability of continuing NIPPV, survival after starting NIPPV, survival after starting home oxygen therapy (HOT), arterial blood gases, nocturnal oxygen saturation, pulmonary function, and the number of hospital days. Two patients with PTS died, 7 and 40 months after starting NIPPV. Two patients (one with PTS and one with COPD) switched from NIPPV to intermittent positive pressure ventilation via a tracheostomy. The condition of one patient with NMD improved and NIPPV was discontinued. The three-year and five-year probabilities of continuing NIPPV in all patients were 82%, and 71%, respectively. The survival rates three and five years after starting NIPPV were 97% and 85%, respectively. The survival rates one to nine years, and ten to eleven years after starting HOT were 98% and 65%, respectively. The arterial PO2 and PCO2, nocturnal oxygen saturation, vital capacity, and forced expiratory volume, in one second all improved after NIPPV was begun. NIPPV also reduced the number of hospital days, particularly in patients with KS. In conclusion, the long-term outcome of NIPPV in patients with hypercapnic respiratory failure is encouraging.

Adult↗
PubMed1996

[A patient with myotonic dystrophy who presented with chest roentgenographic abnormalities and alveolar hypoventilation].

A 52-year-old man had been asymptomatic except for nasal speech since his third decade of life. A chest roentgenogram obtained during a health screening one year before admission revealed elevation of the right hemidiaphragm and infiltrates in the right lower lung field. Because the pulmonary shadows had gradually increased, he was admitted to the hospital, for further examination. Based on physiological findings and on the results of electromyography, myotonic dystrophy was diagnosed. The chest roentgenographic abnormalities were regarded as resulting from complications of this disease. Arterial blood gas analysis showed hypercapnic hypoxia and a spirogram showed that the vital capacity and maximum voluntary ventilation were about half of their respective predicted values. The hypercapnic ventilatory response was also abnormally low. An overnight study of oxygen saturation showed episodes of marked desaturation, and polysomnography revealed central sleep apnea. Inhalation of capsaicin showed an abnormally high cough threshold. Patients with undiagnosed myotonic dystrophy rarely present with chest roentgenographic abnormalities.

Electromyography↗
PubMed1996

[Temporary use of chest negative pressure ventilation to facilitate closure of a tracheal stoma before domiciliary nasal intermittent positive pressure ventilation].

A 67-year-old patient with pulmonary tuberculosis sequela had undergone a tracheostomy. The patient was receiving nasal intermittent positive pressure ventilation and the stoma failed to close. Temporary use of chest negative pressure ventilation facilitated closure of the stoma and probably shortened the patient's hospital stay. Nasal intermittent positive pressure ventilation at home was begun safely and effectively.

Aged↗
PubMed1995

Regulation of transcription of the human erythropoietin receptor gene by proteins binding to GATA-1 and Sp1 motifs.

Erythropoietin (Epo), the primary regulator of the production of erythroid cells, acts by binding to a cell surface receptor (EpoR) on erythroid progenitors. We used deletion analysis and transfection assays with reporter gene constructs to examine the transcription control elements in the 5' flanking region of the human EpoR gene. In erythroid cells most of the transcription activity was contained in a 150 bp promoter fragment with binding sites for transcription factors AP2, Sp1 and the erythroid-specific GATA-1. The 150 bp hEpoR promoter exhibited high and low activity in erythroid OCIM1 and K562 cells, respectively, reflecting the high and low levels of constitutive hEpoR expression. The GATA-1 and Sp1 binding sites in this promoter lacking a TATA sequence were necessary for a high level of transcription activation. Protein-DNA binding studies suggested that Sp1 and two other CCGCCC binding proteins from erythroid and non-erythroid cells could bind to the Sp1 binding motif. By increasing GATA-1 levels via co-transfection, we were able to transactivate the hEpoR promoter in K562 cells and non-erythroid cells, but not in the highly active OCIM1 cells, although GATA-1 mRNA levels were comparable in OCIM1 and K562. Interestingly, when we mutated the Sp1 site, resulting in a marked decrease in hEpoR promoter activity, we could restore transactivation by increasing GATA-1 levels in OCIM1 cells. These data suggest that while GATA-1 can transactivate the EpoR promoter, the level of hEpoR gene expression does not depend on GATA-1 alone. Rather, hEpoR transcription activity depends on coordination between Sp1 and GATA-1 with other cell-specific factors, including possibly other Sp1-like binding proteins, to provide high level, tissue-specific expression.

Cell Line↗
PubMed1995

Clinicopathological study of clear-cell tumors of the thyroid: an evaluation of 22 cases.

Twenty-two cases of partial or wholly composed clear-cell thyroid tumors were reviewed to differentiate between a primary nodule and metastatic clear-cell renal carcinoma in the thyroid. Pathological reevaluation of HE-stained specimens, immunohistochemical observation using anti-thyroglobulin (TG) antibody, and periodic acid-Schiff (PAS) staining were performed. The pathological characteristics in metastases from the kidney have a greater tendency to demonstrate a strikingly clear cytoplasm with small nuclei, rich vascularization, and a trabecular arrangement of tumor cells than do primary thyroid cases. The immunohistochemical TG staining in conjunction with PAS staining for the recognition of follicular colloid could provide much more reliable information of primary cases compared to that using TG staining alone. Clinically, in primary cases, the female:male ratio is substantially higher while the mean age is lower than in metastatic cases reflecting differentiated thyroid carcinoma. In conclusion, immunohistochemical staining for TG with PAS staining for the recognition of follicular colloid proved to be the most sensitive method for identifying primary clear cell thyroid tumors. In addition, a careful assessment of past and/or present kidney disorders to rule out metastatic renal cell carcinoma is advisable. Age, gender, and physiological findings are also informative when differentiating between them.

Adenocarcinoma, Clear Cell↗
PubMed1995

Immunohistochemical study of gamma delta T cell receptor-positive cells in the capsular region of hepatocellular carcinoma: possible role in defense against expansion of carcinoma in the liver.

The localization and distribution of gamma delta T cell receptor (TCR)-positive cells (gamma delta T cells) in hepatocellular carcinoma capsules was investigated immunohistochemically at both light and electron microscopic levels. Most of the mononuclear cells infiltrating the tumor capsules were CD3-positive. Together with gamma delta T cells, they were significantly increased in the tumor capsules compared to amounts in the fibrous septa in non-cancerous cirrhotic areas of the same liver, and compared to amounts in the liver of patients with cirrhosis. Phenotypic characterization by the two-color double-staining technique showed that CD8/gamma delta cells were significantly increased in the tumor capsule, and that more than one-third of gamma delta TCR-positive cells also expressed the CD56 antigen. Morphological observation revealed that large gamma delta T cells were increased in number in the tumor capsule and that the cytoplasm of these cells contained multivesicular bodies and dense granules. These morphological features were similar to those of large granular lymphocytes, and most of the gamma delta T cells were also positive for BB3. This suggests that extrathymic maturation of gamma delta T cells occurs in the tumor capsule, and that these gamma delta T cells may have a cytolytic effect on tumor cells, as shown in large granular lymphocytes; further, the results suggest that these cells may play a role in the defense against tumor expansion.

Aged↗
PubMed1995

Age-related changes in the static and dynamic mechanical properties of mouse lungs.

To investigate the effects of aging on pulmonary mechanical properties in mice, we devised a new experimental apparatus to measure the respiratory impedance of excised lungs in mice and examined age-related changes in both static and dynamic properties. In an accelerated senescence-resistant strain of mice, SAMR1 (Takeda, T., Y. Fukuchi, Y. Uejima, K. Teramoto, T. Oka and H. Orino, J. Am. Geriatr. Soc. 39: 911-919, 1991), ranging from 3 to 24 months of age, static compliance (Cst) as well as total lung capacity increased significantly with age, whereas specific compliance and the K value, as determined by exponential analysis, showed no significant change. In the dynamic study, dynamic compliance (Cdyn) increased significantly with age, whereas the frequency dependence of Cdyn (Cdyn/Cst) did not vary with age. From these results we concluded that lung elasticity, normalized to lung volume, remained constant with age and that the effects of aging on pulmonary mechanics might be solely derived from increases in lung volume in the SAMR1 strain of mice.

Age Factors↗
PubMed1995

Response of rat model of Pneumocystis carinii pneumonia to continuous infusion of deferoxamine.

The iron-chelating drug deferoxamine mesylate (DFO) is active against Pneumocystis carinii in vitro and in rat and mouse models of P. carinii pneumonia. Because DFO has a short half-life, daily divided or continuous dosage was expected to improve the dose response, as is the case with DFO treatment of malaria. Therefore, results of single daily intraperitoneal injections were compared with results of an evenly divided four-times-daily dosage and the efficacy of delivery with implanted infusion pumps. The highest bolus dosage (1,000 mg kg-1 of body weight day-1) was as effective as the standard combination of trimethoprim with sulfamethoxazole. Unexpectedly, very little improvement was observed with the divided or continuous dosage, and several mechanisms that could account for this are discussed.

Animals↗
PubMed1995

Clinically achievable plasma deferoxamine concentrations are therapeutic in a rat model of Pneumocystis carinii pneumonia.

The iron-chelating drug deferoxamine (DFO) has been shown to be active in animal models of Pneumocystis carinii pneumonia (PCP), with effective daily intraperitoneal bolus dosages being 400 and 1,000 mg of DFO mesylate kg of body weight-1 in mouse and rat models, respectively. Continuous infusion produced a moderately improved response in a rat model. The data reported here demonstrate that the response achieved by continuous infusion of 195 and 335 mg of DFO mesylate kg-1 day-1 in the rat model is associated with mean concentrations in plasma of 1.3 and 2.5 micrograms of DFO ml-1 and mean concentrations in lung tissue of 4.9 and 6.0 micrograms of DFO g of lung tissue-1, respectively. Since current clinical use of DFO mesylate for the treatment of iron overload produces higher concentrations in the plasma of patients, DFO may prove to be a useful anti-PCP treatment. The 2.4- to 3.8-fold higher DFO concentration observed in lung tissue compared with that observed in plasma may be important in the response of PCP to DFO.

Animals↗
PubMed1995

Mitochondrial encephalomyopathy with A to G transition of mitochondrial transfer RNA(Leu(UUR)) 3,243 presenting hypertrophic cardiomyopathy.

In a 24-year-old woman with mitochondrial encephalomyopathy presenting hypertrophic cardiomyopathy, microscopical examination of myocardial biopsy specimen disclosed severe vacuolar degeneration of myocardium and aggregates of enlarged mitochondria with proliferated cristae. Limb muscle biopsy specimen showed "ragged-red fibers" light microscopically and enlarged abnormal mitochondria with markedly increased cristae ultrastructurally. Mitochondrial DNA analysis by polymerase chain reaction (PCR) revealed an A-to-G transition in the mitochondrial transfer RNA(Leu)(UUR) gene at nucleotide position 3,243 which is reported to be associated with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). However, the clinical features of this case, presenting mainly cardiac abnormalities, were not consistent with the typical MELAS.

Adult↗