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Biomedical subjects

F Kiya

Publications and source records attributed to F Kiya.

16 recordsLinked to original sources
PubMed1994

[Contamination of hot water supply in office buildings by Legionella pneumophila and some countermeasures].

An assessment of the contamination by Legionella species of hot water supplied to office buildings was made based on 80 samples of water from 3 types of systems as follows: 20 samples supplied from instantaneous heaters, 20 samples from hot water storage type systems, and 40 samples from circulation type systems. Legionella spp. were detected in two samples (10.0%) from hot water storage systems and five samples (12.5%) of the circulation type. The number of Legionella spp. was 2.0 x 10-8.4 x 10(2) CFU/500 ml. All isolated strains were identified as Legionella pneumophila. All hot water samples with Legionella spp. showed a temperature range from 41-55 degrees C. Contamination may easily occur in hot water storage and circulation type systems, due to their presence for prolonged periods. Hot water may be therefor be a source of Legionnaires' disease. It is clear from the present study that Legionella spp. survived over long periods and proliferated considerably. Elimination of this organism requires careful cleaning of hot water storage tanks but this alone may not be sufficient. Heat treatment for 20 hours at 70 degrees C was found to be adequate for complete elimination. Experimentally, complete sterilization from Legionella spp. within 5 minutes was demonstrated by heating at 60 degrees C. As a countermeasure temperature of hot water should be maintained at more than 55 degrees C, as the best means for elimination while also giving consideration to the prevention of scalding.

Hot Temperature↗
PubMed1988

The total heart beats per 24 hours by ambulatory electrocardiography and the changes of heart rate by treadmill exercise test in sick sinus syndrome.

To study the clinical implications of the total number of heart beats per 24 hours (THB), 24 hour ambulatory electrocardiography and treadmill test were performed by sixty patients with sick sinus syndrome (SSS, 58 +/- 12 years old) who underwent overdrive suppression test. Results were compared with thirty control subjects (58 +/- 12 years old). The THB was 74 +/- 11 thousand beats in the SSS group and 99 +/- 10 thousand beats in the control group. The THB and the maximal heart rate (MHR) achieved during the treadmill test were significantly lower in the SSS group than in the control group. However, the exercise duration in patients with SSS was similar to that of the control subjects. The exercise duration and the MHR were correlated to age, but not to the THB in the patients with SSS. There was no significant relationship between the total heart beats per 24 hours and the maximal sinus node recovery time (max. SNRT). We conclude that the THB, independent of the max. SNRT, can be a useful index in diagnosing and assessing the quantity of bradycardia in patients with SSS. The tolerance of exercise and the MHR were not correlated with the THB, in patients with SSS.

Adult↗
PubMed1987

Effects of combined changes in serum calcium and potassium on QT interval. A study by Holter electrocardiographic monitoring during hemodialysis.

Holter electrocardiographic recordings were performed for 24 hours in 20 patients on chronic hemodialysis to evaluate the effect of changes in serum calcium and potassium during a 5-hour hemodialysis period on the QT interval. Hemodialysis caused an acute increase in serum calcium from a predialysis value of 9.6 +/- 1.3 mg/dl to 11.5 +/- 1.2 mg/dl and a decrease in serum potassium from 4.9 +/- 0.6 mEq/L to 3.5 +/- 0.4 mEq/L. The Q-oTc interval shortened from a predialysis value of 0.240 +/- 0.023 sec to a minimum of 0.215 +/- 0.022 sec during the 5th hour of hemodialysis. This Q-oTc interval shortening was correlated strongly with an increase in serum calcium and was statistically significant only in subjects showing an increase in serum calcium of more than 2 mg/dl (p less than 0.05). The Q-eTc interval increased from a predialysis value of 0.392 +/- 0.030 sec to 0.414 +/- 0.024 sec during the 4th hour of hemodialysis. This Q-eTc interval prolongation was correlated with a decrease in serum potassium. It was concluded that increased serum calcium during hemodialysis caused shortening of the Q-oTc interval, that the degree of shortening was proportional to the magnitude of increase in serum calcium, and that changes in serum calcium and the Q-oTc interval were concurrent. It was also concluded that hemodialysis resulted in prolongation of the Q-eTc interval. This change was possibly caused by a decrease in the level of serum potassium during the procedure.

Adult↗
PubMed1987

The QT prolongation syndrome: long-term follow-up study of 13 families with Romano-Ward syndrome.

To investigate the long-term course or natural history of Romano-Ward syndrome, 131 cases from the affected side of 13 families with the syndrome were examined by electrocardiography and a review of the histories. The patients were followed up for 2-13 years, with an average of 7.2 years. Five patients (3.8%) died suddenly, four with QT prolongation and one with a normal QT interval. Fourteen patients (10.7%) with QT prolongation developed episodes of syncope, whereas 58 patients (44.3%) showed only QT prolongation without syncopal episode. Three of the thirteen families were asymptomatic, with no cases of syncopal episodes or sudden death, although more than 50% of the examined cases in these families showed definite QT prolongation. In the other ten families, syncopal attacks and/or sudden death occurred in some of the family members. In two of the ten symptomatic families, the probands developed their first syncopal attacks very late in their lives (at the ages of 64 and 75 years), and both families had been asymptomatic before these elder family members became symptomatic. In two cases, syncopal attacks disappeared after electrocardiographic improvement. The present study suggests that: (a) asymptomatic families of Romano-Ward syndrome exist, (b) asymptomatic families may sometimes become symptomatic, and (c) regression of the manifestations of Romano-Ward syndrome may occur in some cases.

Adolescent↗
PubMed1986

Sinus node function after selective elimination of sympathetic influences on the sinus node area of the dog.

Six-hydroxydopamine (6OHDA) was injected directly into the subepicardium of the sinus node area in an attempt to damage sympathetic nerve terminals in the sinus node. The changes in sinus node function were observed for 4 weeks. The predominant rhythm was of sinus origin throughout the observation period. The sinus rate progressively decreased from 145.1 +/- 14.2 to 76.2 +/- 12.1 beats/min during the first week after injection of 6OHDA. The sinus rate remained at this level for 2 weeks, followed by a gradual increase to 89.3 +/- 18.2 beats/min 4 weeks after injection of 6OHDA. These sinus rates were only significantly different from control dogs through the 14th postoperative day. The sinus rate was considerably increased by intravenous atropine injections 5 to 7 days after the injection of 6OHDA into the sinus node area. The sinus node recovery time was much longer in dogs with an injection of 6OHDA than that in the control dogs throughout the observed period. These results suggest that elimination of the sympathetic influences on the sinus node can be achieved by direct injection of 6OHDA into the sinus node area in the dog, and that sinus node function can be depressed by decreasing sympathetic tone alone, in the absence of an intrinsic dysfunction of the sinus node.

Animals↗
PubMedDate not supplied

Effect of verapamil directly administered into A-V node artery on A-V junctional automaticity and A-V conduction in dogs.

We investigated the direct effects verapamil, which was infused into the A-V node artery at two doses of 0.01 and 0.1 microgram/kg/min on the A-V conduction and the A-V junctional automaticity in the dog with experimentally induced A-V junctional rhythm. Verapamil significantly prolonged the A-H interval, but not the H-V interval, in the His bundle electrogram during atrial pacing at a rate of 100 beats/min. Effective and functional refractory periods of the A-V node also were prolonged significantly by verapamil. On the other hand, verapamil showed less propensity to decrease the spontaneous A-V junctional rate and to prolong the A-V junctional recovery time after atrial overdrive at a rate of 100 beats/min for 60 s. These results indicate that suppressive effects of verapamil on the A-V junctional automaticity are much weaker when compared with that on the A-V conduction.

Animals↗