Rapid detection of mecA gene by nested PCR for diagnosis of methicillin resistance in Staphylococcus aureus]

In recent years, the most common causative organism of hospital infections has been methicillin resistant Staphylococcus aureus (MRSA). The major mechanism of beta-lactam resistance in MRSA is attributed to the production of a specific penicillin binding protein (PBP2'), which is a product of mecA gene, with extremely low binding affinities to beta-lactams. In the present study, we have established a rapid identification method of MRSA by sensitive detection of mecA gene using nested PCR. Nested PCR method amplifying the target DNA in two steps enhanced the efficiency of the second round amplification. By means of this method, mecA gene was successfully detected in clinical samples, such as blood, pus, sputum and feces within 3-4 hrs. Rapid diagnosis of MRSA-bacteremia is particularly important for prevention of sever systemic infection. There are some strains of S. aureus which possess mecA gene in spite of low minimal inhibitory concentration of DMPPC. In these strains expression of mecA gene is induced by contact of beta-lactams and they obtain methicillin resistance. Using nested PCR method, these latent MRSA are rapidly and certainly detectable. This method should be useful for early and effective detection of MRSA hospital infections.     

Universal applications of sentinel node technology

The sentinel node (SN) concept was originally proposed by several pioneers in the middle of the last century. After Donald Morton and his colleagues demonstrated the clinical significance of the SN concept in melanoma, it attracted vast attention in surgical oncology. At recent international conferences, a number of new approaches in this field for various solid tumors have been reported. Now, there are several possible applications with different technological aspects, such as individualized surgical management of solid tumors, multidisciplinary treatments, and novel therapeutic approaches. This article provides an overview of the future potential of SN technology.     

Left ventricular diastolic dysfunction as assessed by echocardiography in metabolic syndrome.

The purpose of the present study was to elucidate the cardiac structure and function in patients who have metabolic syndrome but no history of cardiovascular disease by analyzing echocardiographic findings. Echocardiographic examination was performed to screen for cardiovascular disease in 135 patients who were in their sixties. Patients were divided into metabolic syndrome (n=65, age: 65+/-2.7 years) and non-metabolic syndrome (n=70, age: 66+/-2.5 years) groups based on the criteria for metabolic syndrome proposed by the Japanese Society of Hypertension and seven other societies in 2005. The left ventricular (LV) wall thickness and dimension were measured by M-mode echocardiography. The relative wall thickness, LV mass index, and LV ejection fraction (LVEF) were calculated. LV diastolic function was assessed by the peak velocity of early rapid filling (E velocity) and the peak velocity of atrial filling (A velocity), and the ratio of E to A (E/A) was assessed by the transmitral flow. The Tei index, which reflects both LV diastolic and systolic function, was also calculated. There were no differences in relative wall thickness, LV mass index, or LVEF between the two groups. However, both the EIA and Tei index were significantly different between the metabolic syndrome (0.66+/-0.14 and 0.36+/-0.07, respectively) and non-metabolic syndrome (0.88+/-0.25 and 0.29+/-0.09) groups (p<0.001). These results indicate that patients with metabolic syndrome can have cardiac diastolic dysfunction even if they have neither LV hypertrophy nor systolic dysfunction.     

Further study of nebulisation chemotherapy, a new chemotherapeutic method in the treatment of lung carcinomas: fundamental and clinical.

Nebulisation chemotherapy, a chemotherapeutic method for the treatment of lung cancer that involves the administration of anticancer agents through the inhalation of nebulised aerosols, has been found to be highly effective (Tatsumura et al., 1983a,b). We confirmed that 5-FU administered by this method accumulates in the trachea, bronchi and regional lymph nodes of patients treated before surgery, along with 5-FU metabolites, FUR and FUdR, indicating that 5-FU is directly incorporated and metabolised in the respiratory tract. Parallel result were obtained using mongrel dogs. The 5-FU levels in other organs, such as the heart and liver, were found to be extremely low. Only a trace of 5-FU was found in the serum of both the patients and the dogs. We further investigated the anti-tumour effect of this therapy in ten selected patients and observed a satisfactory anti-tumour response of 60.0%. These results, along with our previous finding that the retention time of isotope tracers inhaled as aerosol is considerably longer in tumour tissues than in normal parts (Tatsumura et al., 1983a) explain the high antitumour action of this therapy and the absence of adverse effects of administered 5-FU.     

Reconstructive surgery for supravalvular aortic stenosis after arterial switch operation for simple transposition in the early neonate

Recently, many papers have reported the development of severe pulmonary stenosis after an arterial switch operation (ASO) for the transposition of the great arteries (TGA) with intact ventricular septum (IVS) in the early neonate. However, supravalvular aortic stenosis after the same procedure is very uncommon. We experienced supravalvular aortic stenosis which developed gradually after successfully performing the Lecompte maneuver for TGA with IVS in a 6-day-old baby. We underwent Doty's extended aortoplasty in his 11th-month. We approached the aorta through the transection of the pulmonary trunk which was located just before the aorta. At the stenotic parts of the aorta, a discrete projection of cicatricial tissue was observed mainly at the posterior wall. The projection of the cicatricial tissue seemed to be induced as a consequence of the contraction of the aortic wall where a continuous suture was tied too tightly with non-absorbable suture materials. To prevent this complication after the Lecompte maneuver for TGA with IVS in the neonate, it is important to take care not to tie the suture too tightly and to use absorbable suture materials for construction of the aorta. There are the recommendations which we observed would prevent the post-operative complication of supravalvular aortic stenosis. As a final note, in repairing the supravalvular aortic stenosis, an approach through the transection of the pulmonary trunk was very useful.     

Formation and the inhibition of reaction plug in mated Drosophila--study of a primitive defense reaction

Formation and inhibition of a reaction plug in the course of insemination reaction in Drosophila (Diptera) were investigated. When the reaction plug was formed in the vagina, fecundity was significantly reduced in interspecific crosses although the reaction plug did not affect the oviposition in intraspecific crosses. Some phenoloxidase blockers were found to be the effective inhibitors. The formation of the reaction plug was likely to be the consequence of polymerization and/or conformational change(s) of phenol-containing substance(s) involving nearly the same course of the melanization cascade reaction studied as a self-defense system in other insects.     

Evaluation of renal first pass blood flow with a functional image technique in hypertensive patients

The renal circulation of patients with essential hypertension and renovascular hypertension was evaluated using ^99mTc-DTPA. The first renal peak count (the first C_max; FC_max), time phase distribution (the first T_max; FT_max), and blood velocity (the FC_max/FT_max) were calculated by digital imaging. This yields a visual image of the renal circulation. We consider that the increase in the renal first pass blood flow in patients with essential hypertension is best observed pixel by pixel. The FC_max and FC_max/FT_max images before and after treatment by percutaneous transluminal renal angioplasty in patients with renovascular hypertension clearly show its therapeutic effect. The FI technique, therefore, has the advantage that it can be performed at the same time as the conventional routine examinations of renal function. This makes it very useful clinically.     

‘Ischemic tolerance’ phenomenon detected in various brain regions

We investigated the effects of mild and non-lethal ischemic insult on neuronal death following subsequent lethal ischemic stress in various brain regions, using a gerbil model of bilateral cerebral ischemia. Single 10-min ischemia consistently caused neuronal damage in the hippocampal CA1, CA2, CA3 and CA4, layer III/IV of the cerebral cortex, dorsolateral part of the caudoputamen and ventrolateral part of the thalamus. On the other hand, in double ischemia groups, 2-min ischemic insult 2 days before 10-min ischemia exhibited significant protection in the CA1 and CA3 of the hippocampus, the cerebral cortex, the caudoputamen and the thalamus. Five-min ischemic insult 2 days before 10-min ischemia also showed protective effect in the same areas as those of 2-min ischemia except for the CA1 region of the hippocampus, while 1-min ischemic insult exhibited no protective effect in any brain regions. In the immunoblot analysis, both 2- and 5-min ischemia caused increased synthesis of heat shock protein 72 (HSP 72) in the hippocampus, but 1-min ischemia did not. The present study demonstrated that the ‘ischemic tolerance’ phenomenon was widely found in the brain and also suggested that ischemic treatment severe enough to cause HSP 72 synthesis might be needed for induction of ‘ischemic tolerance’.     

Papillary thyroid cancer and its surgical management.

The surgical management in papillary thyroid cancer has been highly controversial. In the Department of Surgery (II), Kanazawa University Hospital, the surgical management especially for cervical lymph node metastases has changed since 1973 from a conservative approach to an aggressive one. In order to determine whether an aggressive approach is warranted, a retrospective multivariate analysis was carried out on 106 cases of papillary thyroid cancer. The patients have been followed for 10-28 years. Multivariate analysis was conducted following Cox's model. By this analysis, aggressive management appeared to have no impact on survival or relapse-free survival. However, age, sex, tumor size, and cervical lymphadenopathy were confirmed to be important prognostic factors in survival and/or relapse-free survival.