Shoko Nakao

Analysis of chest CT in patients with Mycobacterium avium complex pulmonary disease.

Background: The radiographic changes of Mycobacterium avium complex (MAC) pulmonary disease during therapy have not been studied well. Objective: To assess the efficacy of antituberculous drug therapy against MAC pulmonary disease using computed tomography (CT). Method: We analyzed chest CT scans before and after antituberculous therapy in 30 patients (21 women, 9 men) with MAC pulmonary disease. To evaluate radiographic changes during therapy, we defined a ‘degree of improvement’ (DI) that is calculated according to the CT appearance. Results: DI was better (1.35 ± 0.21) in patients who had converted sputum culture than in those who had not (0.44 ± 0.25) (p < 0.05). In patients who were diagnosed by bronchial washing, DI was better (1.60 ± 0.22) than in patients who were diagnosed by sputum (0.67 ± 0.20) (p < 0.01). We categorized the CT appearance into 6 types: small nodules, cavities, bronchial wall thickening, infiltration, pleural thickening and atelectasis. Patients who showed pleural thickening had a significantly worse DI (0.12 ± 0.40) than those who did not (1.23 ± 0.18) (p < 0.01). Most of the lesions that disappeared after therapy were small nodules. Conclusion: These results indicate that chest CT might be a useful tool for the prediction or assessment of drug therapy for MAC pulmonary disease.

Alterations in penicillin binding protein gene of Streptococcus pneumoniae and their correlation with susceptibility patterns

Penicillin binding protein (pbp) gene alterations of 328 clinical isolates of Streptococcus pneumoniae were examined for a correlation with their antibiotic-resistance. The frequency of penicillin G (PEN-G) resistance was determined to clarify susceptibility to several antibiotics, namely PEN-G, ampicillin, sulbactam/ampicillin, cefozopram, panipenem (PAPM), clarithromycin (CLR), azithromycin (AZM) and levofloxacin (LVX). Oligonucleotide primers for three pbp genes (pbp1a, pbp2x and pbp2b) were used to detect mutations in pbp. Of the strains, 25.9% were classified as Pen-Gs, 68.0% as Pen-Gir and 6.1% as Pen-Gr. The polymerase chain reaction product for wild-type pbp1a was found in 185 isolates, that for wild-type pbp2x was found in 66 isolates and that for wild-type pbp2b was found in 213 isolates. None of these three genes was detectable in 100 isolates while all of them were detected in 64 isolates (1aw/2xw/2bw). Of those 64 isolates with 1aw/2xw/2bw, the minimum inhibitory concentration (MIC) of PEN-G was < or =0.06 mg/l for 54 isolates and 0.12 mg/l for 10 isolates. Of the 272 strains for which the MIC of PAPM was < or =0.03 mg/l, there were 85 Pen-Gs, 184 Pen-Gir and three Pen-Gr isolates. Three strains for which the MIC of LVX was > or =4.0 mg/l included one Pen-Gs and two Pen-Gir isolates. The MICs of CLR correlated significantly with those of AZM. The MIC of CLR was > or =1 mg/l for 216 isolates, and the MIC of AZM was > or =1 mg/l for 244 of them. These data suggested that PAPM may be effective against S. pneumoniae infection, although acquisition of resistance should be considered. LVX also seemed to be effective against S. pneumoniae.

Detection of Photofrin Fluorescence From Malignant and Premalignant Lesions in the Bronchus using a Full-color Endoscopic Fluorescence Imaging System.

Study objectives: To detect invisible lung cancer and to determine field of laser radiation during PDT we developed a full-color fluorescence fiberscopic system. We tested the efficacy of this system in patients with various bronchial malignancies. System design: A fiber-optic endoscope was attached to a camera box containing a color ICCD camera which can detect from 400 to 700nm fluorescence in full-color. Light of average wavelength 405 nm was selected and radiated through the light channel of the fiberscope from a 300W Xenon lamp. Patients and methods: We examined nine consecutive patients with bronchial malignancy admitted in our hospital to receive PDT. Sixteen lesions in these nine patients were observed with white light and excitation light and the results were compared. Histological examinations were done by taking biopsy specimens and samples for pathological and cytological examination. After the diagnosis was confirmed, 2.0 mg/kg Photofrin was injected. Forty eight hours after the administration of Photofrin, observation of the bronchial wall was made using a full-color endoscopic fluorescence imaging system just before PDT. Results: Bright red fluorescence from Photofrin was Observed in 14/14 bronchial malignancies: 3 squamous cell carcinoma, 9 squamous cell carcinoma in situ, 1 metastatic breast cancer and 1 metastatic islet cell tumor. Bright red fluorescence was also detected in 2/2 squamous dysplasia. Green autofluorescence was observed in the normal part of the bronchus. Conclusions: Results of the present study suggest that the full-color endoscopic fluorescence imaging system can be used to detect malignant and premalignant lesions as red fluorescence against green autofluorescence with Photofrin administration, and this system has the potential to detect absence of autofluorescence in cancerous lesions.

Stimulus Interaction between Hypoxia and Hypercapnia in the Human Peripheral Chemoreceptors

interaction between hypoxia and hypercapnia in peripheral chemoreceptors has been clearly demonstrated in experimental animals, there have been limited studies targeted in human. It is difficult to distinguish peripheral chemoreception from central chemoreception in steady-state ventilatory response to hypercapnia, since inspired hypercapnic gas stimulates both peripheral and central chemoreceptor. On the contrary, “two breaths method” has been used to estimate the peripheral chemoreceptor activity in human. In this method, transient alteration of ventilation with two breaths of hypoxic gas or hypercapnic gas may show the peripheral chemoreceptor activity. In the present study, we evaluate the ventilatory response to combined effects of hypoxia and hypercapnia in the peripheral chemosensitivity in healthy human by using two breaths method.

Peripheral chemoreceptor activity on exercise-induced hyperpnea in human

The PCA was studied in ten healthy volunteers (38 +/9 yr, 75 +/16 kg, mean +/SD) during rest and exercise. The study was approved by the institute committee of human studies, and informed consent was obtained from each subject. They performed cycle ergometer exercise increasing by 25 W every 10 min in the stepwise manner. Arterial blood was sampled to analyze blood gases and to measure serum [K], [lactate] and [noradrenaline] at rest, and in early phase (3 min) and in late phase (10 min) of each step of exercise. The PCA related to O2 sensing was estimated by measurement of decline of minute ventilation ( V’I) during 5 to 15 sec after transient two breaths of pure oxygen (Fig. 1). In this test, the high inspired O2 fractions suppress peripheral chemosensory contribution to ventilatory drive before change the condition of central chemoreceptor (Dejours, 1964). The measurements of V’I were practiced at rest, and in early phase and in late phase of each step of exercise. The contribution of PCA in entire ventilatory gain (% V’I) was calculated as follows:

A case of lung cancer in which atypical spindle cells were found together with small cell cancer cells in the cytological specimen.

背景:喀出された腫瘍片の細胞診, 組織診で異型間質細胞を認めた肺小細胞癌の1例を経験した.症例:76歳の男性. 右肺下葉の結節性陰影と縦隔リンパ節の腫大を認めたため肺悪性腫瘍が疑われた. 喀痰採取時に組織片を喀出し, それを検体として細胞診, 病理組織診を行った. 細胞診では壊死性物質を背景に, 小型で裸核状の腫瘍細胞が木目込み配列を伴った結合性の弱い細胞集塊として多数出現しており肺小細胞癌を疑った.同時に紡錘形異型細胞や多核の巨細胞を多数認めた. これらの異型細胞は抗NSE抗体では染色されなかった. 組織像では紡錘形異型細胞を小型の腫瘍細胞巣の周囲に認めた. この紡錘形細胞は抗NCAM抗体では染色されず, 抗vimentin抗体, 抗actin抗体で一部の細胞が染色された.結論:細胞診に出現していた紡錘形異型細胞や多核巨細胞は, 腫瘍周囲に増生し異型を示した線維芽細胞と筋線維芽細胞と考えられた.