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Biomedical subjects

K Kono

Publications and source records attributed to K Kono.

At least 145 records · Page 8Linked to original sources
PubMed1993

Fusion activity of an amphiphilic polypeptide having acidic amino acid residues: generation of fusion activity by alpha-helix formation and charge neutralization.

A sequential polypeptide, poly(Glu-Aib-Leu-Aib) (Aib represents 2-aminoisobutyric acid), was synthesized and the pH-dependence of fusogenic activity of the polypeptide was studied. The polypeptide was designed to take amphiphilic structure upon the formation of alpha-helix. Circular dichroism spectra of the polypeptide showed a negative Cotton effect with double minima, indicative of an alpha-helical conformation. The alpha-helix content was increased with lowering pH and/or increasing the ionic strength. It was found that the polypeptide induces remarkable leakage of calcein from egg-yolk phosphatidylcholine (EYPC) vesicles loaded in the inner aqueous phase with lowering pH and/or increasing ionic strength. The polypeptide caused fusion of EYPC liposomes and dipalmitoylphosphatidylcholine liposomes more strongly with decreasing pH. Moreover, two distinct increases of fusogenic activity of the polypeptide were observed near pH 6.0 and below pH 4.5. The former corresponds to the midpoint of pH-dependent change in helical content of the polypeptide and the latter the pKa of the gamma-carboxyl group of glutamic acid. These results indicate that elevation of the fusogenic activity of the polypeptide is related to the increase in two factors, alpha-helix content and hydrophobicity.

Amino Acid Sequence↗
PubMed1993

Urine, serum and hair monitoring of hydrofluoric acid workers.

To define the relationship between fluoride (F) concentration in the serum, urine and hair of workers and the concentration of hydrofluoric acid (HF) in the work environment, pre- and postshift serum and urine samples of 142 HF exposed workers and 237 unexposed workers were examined. Hair specimens were also collected for the determination of F. To determine whether external contamination influences hair analysis, the control hair samples were kept in the work environment for one week. The pre-exposure levels in serum and urinary F in HF workers were higher (P < 0.01) than the control values. This suggests that F excretion from the body continues for at least 12 hours. The postshift serum and urinary F concentrations of these workers were significantly higher (P < 0.01) than the preshift concentrations. The levels of F in the hair of HF workers were also higher than in the control subjects. The concentrations of F in postshift serum and urine, and hair were in good correlation to each other. There was a linear relationship between mean serum and urinary F concentrations and HF concentration in the workplace. A mean F concentration of 82.3 micrograms/l in serum and 4 mg/l in urine with a lower fiducial limit (95%, P = 0.05) of 57.9 micrograms/l in serum and 2 mg in urine were estimated to correspond to an atmospheric HF concentration of 3 ppm, which is the maximum allowable concentration recommended by Japan Association of Industrial Health and also the threshold limit value suggested by American Conference of Governmental Industrial Hygienists.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

New interpretation of systolic time intervals from active cross-bridge model.

Using an active cross-bridge model proposed by the authors, it has been established theoretically that cross-bridge activation rate (Ka) of the left ventricular myocardium, which might correspond to the rate of binding of Ca2+ with troponin C, is approximately expressed as a simple formula: Ka = 3/electromechanical systole (sec-1), although no definitive biological proof has yet been provided for the equation. One hundred eighteen patients without significant cardiac disease and 6 patients who had atrioventricular block with a permanent pacemaker were evaluated to determine the Ka value of the normal human left ventricular myocardium (test 1), and to examine the effect of changes in heart rate (test 2) as well as afterloading (test 3) or dobutamine infusion (test 4) on Ka. The pacing rate was increased from 50 to 110 beats/min at 20-beat increments in test 2. Arterial pressure was elevated by angiotensin II infusion in test 3, and 7 subjects received a continuous dobutamine infusion in test 4. The Ka value was found to be related to heart rate, to be increased by dobutamine infusion, and to be decreased by myocardial lengthening due to afterloading. Dependence of Ka on heart rate appeared to result from changes in myocardial length. The Ka value corrected for heart rate (Kac) had an average variation of only 4.6%, and was unrelated to age or myocardial length in individual subjects. Thus, the Kac value of normal human left ventricular myocardium appears to be nearly constant between individuals but to be increased by catecholamine infusion or myocardial shortening.

Adult↗
PubMed1993

[The effect of soluble fiber dietary supplement on constipation in 3 patients with dysphagia who suffered from cerebral infarction with special reference to serum diamine oxidase activity].

Dietary supplement with soluble fibers was given to 3 patients with stroke and dysphagia and obtained improved defecation condition. These clinical effects of soluble fibers should reduce the burden of the patients and families. Long-term inaction of the gastrointestinal tract or continuation of supplementary diet without fibers will induce atrophic intestinal mucosa and abnormal intestinal function. The addition of dietary soluble fibers into supplementary diet can improve the atrophy of the intestinal mucosa and the decline in function of the intestine, constipation and meteorism. The serum diamine oxidase activity, which is regarded as a parameter of intestinal mucosal atrophy, increased with the improvement of constipation and meteorism after addition of dietary soluble fibers. We think that dietary soluble fibers are necessary, especially for the patients who have low diamine oxidase activity. The measurement of serum diamine oxidase activity should be an effective method to evaluate intestinal mucosal atrophy and estimate dietary fibers. We selected a supplementary diet, Enrich-SF, which contains Fibaron, a kind of soluble fiber, galactomannan purified from guar, because this canned supplementary diet has only one kind of soluble fiber. Some consider that soluble fibers are fermented to short-chain fatty acids in the intestinal tract, and improve the disordered bacterial flora in the intestine, resulting in more regular intestinal function. Attention should be paid to dietary fibers in cases of long-term tube feeding.

Aged↗
PubMed1993

[Anesthetic management of a patient with polyarteritis nodosa who suddenly developed cardiac rupture after valve replacement].

We recently encountered a patient with mitral insufficiency, accompanied by PN (polyarteritis nodosa), who developed a cardiac rupture immediately after a mitral valve replacement. The patient was a 60-year-old woman. After she was diagnosed as having mitral stenosis and insufficiency in 1968, the patient developed congestive heart failure and underwent repeated hospital admissions and discharges. In 1989, she was diagnosed as having PN and began to receive a high-dose steroid therapy (prednisolone; total dose 5245 mg). Because of transient brain ischemia and exacerbation of the symptoms of heart failure, the patient underwent mitral valve replacement on December 19, 1991. For anesthesia, oxygen, fentanyl, midazolam and vecuronium were administered. During surgery, catecholamine, nitroglycerin and prostaglandin E1 were continuously infused intravenously. The patient was weaned smoothly from the cardiopulmonary bypass. The operation was completed in about 6 hours. Her postoperative course was satisfactory until she suddenly developed left ventricular rupture and died 6 hours after surgery. The rupture seemed to be attributable to a weakening of the myocardial wall following long-term, high-dose steroid therapy, and to myocardial degeneration caused by PN-associated necrotizing vasculitis of myocardial arterioles.

Female↗
PubMed1993

[Anesthetic management for cesarean section of a patient with transient diabetes insipidus and acute severe liver dysfunction].

A 26-year old woman presented with acute hepato-renal dysfunction, coagulation abnormalities and diabetes insipidus associated with hypernatremia in the latter term of pregnancy (39 weeks). Such transient diabetes insipidus during pregnancy as in this case has been reported to be resistant to AVP, but to respond to DDAVP. Because of fetal compromise, an urgent cesarean section was performed. Spinal anesthesia was chosen because of the possible deleterious effects of general anesthesia on liver function. After delivery of twin babies, her symptoms recovered gradually. In conclusion, diabetes insipidus during pregnancy as in this case is transient and disappear after delivery. However, multiple organ dysfunction may become worse and cause fetal death, unless surgical procedure with appropriate anesthetic management is performed.

Acute Disease↗
PubMed1993

Elemental analysis of hair among children living in Bangkok, Negros Island and Takarazuka. A comparative study in three countries.

Twelve elements in the hair of children living in Bangkok (Thailand) were compared with those of children living in Negros Island (Philippines) and Takarazuka (Japan). With the exception of lower Se and F values, the contents of Ca, Mg, Na, K, Fe and Al in the hair of children in Bangkok were higher than those in Japanese children. A high coefficient of correlation was obtained between Cu and Fe, Cu and Mn, Se and Fe, Se and Cu, Se and Mn in the children of Bangkok. These findings were not found in other groups.

Child↗
PubMed1993

[Successful anesthetic management of a patient with a giant mediastinal tumor].

Because of its anatomical location, mediastinal tumor is frequently accompanied by airway stenosis and signs indicating compression of the heart and large vessels. For this reason, a patient with this tumor often requires an urgent operation. We recently conducted such an operation on a girl 2 year and 7 month old in whom a giant tumor originating from the posterior mediastinum had caused dyspnea. In this case, anesthesia was induced with ketamine. Intubation was carried out while the girl was semiawake. No muscle relaxants were used, and spontaneous ventilation was partially preserved. During the operation, anesthesia was maintained with oxygen, nitrous-oxide and halothane, without using muscle relaxants. Although intratracheal bleeding, caused by manipulation of the tumor, aggravated the blood gas data, this could be coped with by elevating the oxygen concentration in the inspired gas. During the operation, respiratory control with 10cmH2O PEEP was carried out to cope with atelectasis from lung compression by the tumor. The postoperative course was excellent. From anesthetic management of this case we emphasize the following points: (1) preoperative assessment of the relationship between posture and dyspnea and assessment of the locational relationships of the tumor, heart, vessels and trachea, using CT, ultrasonography, bronchoscopy, etc; (2) utilizing a pulse oximeter, monitoring CO2 in expired gas and monitoring CVP during operation; (3) avoidance of the use of muscle relaxants before the improvement of the symptoms arising from tumor-caused compression; and (4) close respiratory care after operation.

Anesthesia↗
PubMed1992

An experimental study on the treatment of hydrofluoric acid burns.

A 20% solution of hydrofluoric acid (HF) was applied to the skin of rats and a biomedical observation of the tissues and sera was made. Flushing with running water was effective for HF burns. By applying 2.5% calcium gluconate jelly, concentrations of fluoride in the urine and the tissues surrounding the injured region were reduced. Thus, the results proved that irrigation with running water and jelly applications were evaluated as the most effective therapy among various methods tested for HF burns.

Animals↗
PubMed1992

Serum fluoride as an indicator of occupational hydrofluoric acid exposure.

To define the relationship between ionic fluoride concentration in the serum of workers and the amount of hydrofluoric acid (HF) in the work environment, pre-and postshift serum and urine samples of 142 HF workers and 270 unexposed workers were examined. The maximum and minimum concentrations of HF in the air in each workshop varied from the mean by less than 30%. The preexposure levels of serum and urinary fluoride in HF workers were higher (P < 0.001) than the control values. This suggests that fluoride excretion from the body continues for at least 12h. The postshift serum and urinary fluoride concentrations of these workers were significantly higher (P < 0.001) than the preshift concentrations. A good correlation (r = 0.64) was obtained between postshift serum fluoride and postshift urine fluoride. There was a linear relationship between mean serum fluoride concentration and HF concentration in the workshop. A mean fluoride concentration of 82.3 micrograms/l with a lower fiducial limit (95%, P = 0.05) of 57.9 micrograms/l was estimated to correspond to an atmospheric HF concentration of 3 ppm. This is the maximum allowable environmental concentration recommended by the Japanese Association of Industrial Health, and it is also the threshold limit value suggested by the American Conference of Governmental Industrial Hygienists. The results demonstrate that exposure to HF can be monitored by determining the serum fluoride concentration.

Adolescent↗