Diagnostic Availability of PCR in the Mycoplasma pneumoniae Pneumonia of Children / 소아알레르기및호흡기학회지

PURPOSE: Mycoplasma pneumoniae is one of the most common causes of pneumonia in children and adolescents. Though cold agglutinin test and specific antibody test are used in the diagnosis of mycoplasma pneumonia, there are some limitations in early diagnosis. In this study, we evaluated the availability and usefulness of polymerase chain reaction (PCR) in the diagnosis of M. pneumoniae pneumonia and compared it with serologic test. METHODS: One hundred twenty four children who were clinically diagnosed with pneumonia and admitted to Kyunghee Hospital from January 1998 to March 2001 were enrolled. Mycoplasma specific antibody test using commercial kit (Serodia-MYCO II, Fusirebio Inc., Tokyo, Japan) and PCR using mycoplasma DNA obtained from throat swabs were done. The sensitivity and specificity of PCR were evaluated. RESULTS: M. pneumoniae pneumonia was diagnosed when the mycoplasma specific antibody titer was over 1: 160 or when the titer increased more than fourfold during follow-up period. The specificity, sensitivity, false-positive rate and false-negative rates of PCR were 93.0%, 58.3%, 33.3%. and 9.7%, respectively. CONCLUSION: PCR has shown high specificity. But, the positive result in PCR don't correlate with the disease activity and PCR does not have high sensitivity. So PCR must be used alongside with serologic test in the diagnosis of pneumonia. But, it seems possible to improve sensitivity by delicate handling of samples and by improving PCR technology, and PCR will possibly be used in the diagnosis of early infections of M. pneumoniae pneumonia and in the evaluation of treatments in the future.

Altered Calcium Current of the Vascular Smooth Muscle in Renal Hypertension

The present study was aimed at investigating whether the calcium current in the vascular smooth muscle (VSM) cells is altered in renal hypertension. Two-kidney, one clip (2K1C) and deoxycorticosterone acetate (DOCA)-salt hypertension were made in Sprague-Dawley rats. Rats without clipping the renal artery or implanting DOCA were used as control for 2K1C and DOCA-salt hypertension, respectively. Four weeks after clipping, systolic blood pressure was significantly higher in 2K1C rats than in control (192+/-24 and 119+/-4 mmHg, respectively, n=16 each). DOCA-salt rats also showed a higher blood pressure (180+/-15 mmHg, n=18) compared with control (121+/-6 mmHg, n=14). VSM cells were enzymatically and mechanically isolated from basilar arteries. Single relaxed VSM cells measured 5 ~ 10 mum in width and 70 ~ 150 mum in length were obtained. VSM cells could not be differentiated in size and shape between hypertensive and normotensive rats under light microscopy. High-threshold (L-type) calciumcurrents were recorded using whole-cell patch clamp technique. The amplitude of the current recorded from VSM cells was larger in 2K1C hypertension than in control. Neither the voltage-dependence of the calcium current nor the cell capacitance was significantly affected by 2K1C hypertension. By contrast, the amplitude of the calcium current was not altered in DOCA-salt hypertension. These results suggest that high-threshold calcium current of the VSM cells is altered in 2K1C hypertension, and that calcium channel may not be involved in calcium recruitment of VSM in DOCA-salt hypertension.

A Long - term Effect of Pentobarbital on the Atrial Natriuretic Peptide System in Rats / 대한마취과학회지

A long-term effect of pentobarbital on the atrial natriuretic peptide (ANP) system was investigated. The experimental group of rats (Sprague-Dawley, male) was one week previously treated with pentobarbital (50 mg/kg, intraperitoneal), and the control was an age-matched group of rats which had never been anesthetized. ANP reaponse to volume-expansion (VE) induced by intravenous infusion of iso-oncotic saline over 30 min (total volume infused amounted up to 5% body weight) was examined under thiopental anesthesia (50 mg/kg, intraperitoneal). Basal plasma ANP level did not significantly differ between the experimental and control groups. Following VE, while the plasma ANP five-fold increased in the control, it rather decreased in the experimental group. Despite the different ANP responses, the magnitude of urinary responses (volume and sodium excretion) to VE did not differ between the two groups. Right and left atrial tissue contents of ANP were significantly lower in the experimental group than in the controL In another series of experiments, the two-kidney, one clip rats were made under either pentobarbital or ether anesthesia and the blood pressure and ANP responses were compared. While the magnitude of blood pressure increases did not differ, the plasma ANP level measured on Day 12 after the clipping was lower in the pentobarbital group than in the ether group. These results suggest that pentobarbital has a long-term inhibitory effect on the ANP system. Its physiological significance in blood pressure and body fluid homeostasis remains to be determined.