Biomedical subjects
H Uematsu
Publications and source records attributed to H Uematsu.
Non-invasive estimation of the net influx constant using the standardized uptake value for quantification of FDG uptake of tumours.
To reduce the variability of the standardized uptake value (SUV) which is widely used to evaluate 2-[18F]fluoro-2-deoxy-d-glucose (FDG) uptake by neoplasms, net influx constant (Ki) was derived from SUV. The relationship Ki=SUV.kp.V0, where kp is the plasma clearance rate and V0 is the initial distribution volume of FDG, was utilized. A total of 71 plasma input functions were measured up to 60 min after intravenous injection of FDG in 55 patients and were analysed to obtain kp and V0. SUV and V0 were calculated based on either body weight or body surface area. To validate the Ki estimation, another group of eight patients with squamous cell carcinoma of the head and neck was included. Parametric images of the net influx constant were obtained by Patlak graphical analysis of dynamic positron emission tomography (PET) data and measured plasma input function. V0 based on body weight was 0.1627+/-0.0329 (ml/g) and showed a weak negative correlation with body weight (y=0.23356-0.00138x, r=0.591). V0 based on body surface area was 5540+/-871 (ml/m2) and had no significant correlation with body weight. kp at 50 min post injection was 0. 03272+/-0.00243 (1/min), and had no correlation with the plasma glucose concentration. A highly significant positive correlation was noted between true Ki and estimated Ki based on both body weight (y=0.0033+1.0371x, r2=0.897), and body surface area (y=0.0033+1. 0351x, r2=0.926). Ki, a better indicator of FDG uptake by tumour than SUV, is derivable non-invasively. Quantification of FDG uptake by Ki will aid standardization of diagnostic criteria of FDG PET oncology.
Multiple single sections Turbo FLASH MR arterial portography in the detection of hepatic neoplasms.
OBJECTIVE: To determine the sensitivity of multiple single sections Turbo FLASH MR arterial portography (MRAP) in the detection of hepatic neoplasms. METHODS AND PATIENTS: Twelve patients with hepatic mass underwent MRAP prior to hepatic resection. Findings of MRAP were compared with surgical specimen and intra-operative ultrasonography (US). RESULTS: A total of 19 separate malignant neoplastic nodules were identified in the resected specimens or intra-operative ultrasonography. The sensitivity was 89.5% (17/19) for MRAP. MRAP depicted all neoplasms more than 1.0 cm in diameter. Two lesions not depicted on MRAP had a diameter of 5 and 9 mm, respectively. One lesion identified by MRAP was confirmed to false positive lesion by intra-operative US. CONCLUSION: Multiple single sections Turbo FLASH MRAP may be a valuable adjunct for pre-operative detection of malignant hepatic neoplasms.
Dive Europa: a search-for-life initiative.
Liquid water, underwater volcanoes and possibly life forms have been suggested to be present beneath the estimated 10 km-thick ice shell of Europa the Jovian satellite J2. Europa's possible ocean is estimated to be 100-200km deep. Despite the great depth of the Europa's ocean, hydrostatic pressure at the seafloor would be 130-260 MPa, corresponding to 13-26 km depth of a theoretical Earth's ocean. The hydrostatic pressure is not beyond the edge of existing deep-sea technology. Here we propose exploration of Europa's deep-sea by the use of current technologies, taking a symbolic example of a deep submergence vehicle Shinkai 6500 which dives to a depth of 6.5 km deep (50 km depth of Europa's ocean). Shinkai 6500 is embarkable in the payload bay of the Space Shuttles in terms of size and weight for the transportation to a Low Earth Orbit (LEO). Secondary boost is needed for interplanetary flight from the LEO. On-orbit assembly of the secondary booster is a technological challenge. The International Space Station (ISS) and ISS-related technologies will facilitate the secondary boost. Also, ice shell drilling is a challenge and is needed before the dive into Europa's ocean. These challenges should be overcome during a certain leading time for matured experience in the ISS operation.
Fluorine-18-fluorodeoxyglucose PET versus thallium-201 scintigraphy evaluation of thyroid tumors.
UNLABELLED: To determine whether PET could help differentiate malignant from benign thyroid tumors, 18F-fluorodeoxyglucose (FDG) accumulation and 201Tl scintigraphy were examined relative to histological diagnosis. METHODS: Nodular thyroid lesions in 11 patients were evaluated before surgical resection. Static PET scanning with 370 MBq FDG was done for 20 min (from 40 to 60 min postinjection) in all patients, and standardized uptake values (SUVs) in these lesions were calculated. In addition, eight patients were evaluated with dynamic PET scan up to 60 min postinjection, and the lesions were further evaluated using graphical analysis. Thallium-201 delayed images were visually evaluated in 10 patients. RESULTS: Four of 11 nodules were well-differentiated papillary carcinoma, another five were benign follicular adenomas, one was a multinodular goiter and another a case of chronic thyroiditis that was proved not to contain a nodule. Time-activity curves of FDG uptake showed different patterns in malignant and benign tumors. In the malignant tumors, FDG uptake increased with time after the tracer injection. By contrast, FDG uptake in benign tumors gradually decreased. With use of a cutoff value of 5.0 mg/ml for SUV and 10 microl x min(-1) x ml(-1) for Kc (K complex value determined using the linear fitting of the time-activity curve of FDG accumulation), all of the four malignant nodules and the six benign nodules were separated correctly. Chronic thyroiditis had high SUV in the malignant range. Of the four patients with thyroid carcinoma, the delayed 201Tl images revealed a slightly higher or equal uptake to background activity. In a patient with chronic thyroiditis, the delayed 201Tl images revealed diffuse accumulation higher than background activity. CONCLUSION: FDG-PET is superior to 201Tl in differentiating malignant from benign tumors. Both SUVs and Kc values were useful indexes for this discrimination. Although careful evaluation is needed for chronic inflammatory lesions, this technique appears to be useful in evaluating thyroid nodules.
Coregistration of FDG PET and MRI of the head and neck using normal distribution of FDG.
UNLABELLED: For better localization of head and neck structures by PET with 2-(18)F-2-deoxy-D-glucose (FDG), direct incorporation of anatomical information from MRI by the coregistration of FDG PET and MRI without external markers is proposed. METHODS: Seventeen patients with neoplasms and 16 normal subjects who had both FDG PET and MRI were studied. First, the three-dimensional normal distribution of FDG was evaluated, and then the structures of the head and neck regions with normal distribution patterns of FDG were used as internal markers for the coregistration of PET and MRI. The effectiveness of the coregistration was evaluated using focal neoplasms that were identified by both PET and MRI as fiducial internal markers. RESULTS: The normal structures selected as internal landmarks for coregistration were the tonsils, salivary glands, mucosal layers of the oral cavity and pharynx, spinal cord, inferior portion of the frontal lobe, cerebellum and nasal turbinates. These structures were more easily observed in sagittal or coronal sections than in transaxial sections. All primary neoplasms were delineated by PET, whereas 4 were missed by MRI. Thirteen primary tumors and 7 cervical lymph node metastases coregistered well, with a center-of-mass distance of <2 mm, whereas 10 lymph node metastases were slightly misregistered, with a center-of-mass distance of 7.8+/-6.5 mm (mean+/-s.d.), probably due to differences in neck positions. CONCLUSION: Normal distribution of FDG uptake in the head and neck regions delineated by multidirectional sections is important for effective coregistration of FDG PET with MRI.
Inhibitory effects of metronidazole on anaerobic metabolism of phenylalanine and leucine by Peptostreptococcus anaerobius.
The metabolism of phenylalanine and leucine by Peptostreptococcus anaerobius and the effects of metronidazole on this metabolism were studied. The cells metabolized both phenylalanine and leucine under strict anaerobic conditions and produced hydroxylated products (i.e. phenyllactate from phenylalanine and hydroxyisocaproate from leucine). Other products were phenylpropionate, cinnamate and phenylacetate from phenylalanine; isocaproate, alpha-ketoisocaproate and isovalerate from leucine. Metronidazole inhibited the production of all end-products, with the exception of phenyllactate and hydroxyisocaproate which were increased. Similarly, when the reaction was carried out aerobically, the cells also metabolized both phenylalanine and leucine and all end-products were inhibited again with the exception of phenyllactate and hydroxyisocaproate. Our results suggest that the inhibitory mode of metronidazole is similar to that of oxygen.
[The out look for home care--from the standpoint of medical association].
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In-vitro antibacterial susceptibility of bacteria taken from infected root dentine to a mixture of ciprofloxacin, metronidazole and minocycline.
The aim of this study was to clarify the antibacterial effect of a mixture of ciprofloxacin, metronidazole and minocycline, with and without the addition of rifampicin, on bacteria taken from infected dentine of root canal walls. The efficacy was also determined against bacteria of carious dentine and infected pulps which may the precursory bacteria of infected root dentine. This efficacy was estimated in vitro by measuring bacterial recovery on BHI-blood agar plates in the presence or absence of the drug combination. Bacteria ranging in number from 10(2) to 10(6) occurred in samples of infected root dentine (27 cases). However, none was recovered from the samples in the presence of the drug combination at concentrations of 25 micrograms ml-1 each. The respective drug alone (10, 25, 50 and 75 micrograms ml-1) substantially decreased the bacterial recovery, but could not kill all the bacteria. Bacteria taken from carious dentine (25 cases) and infected pulps (12 cases) were also sensitive to the drug combination. These results may indicate that the bactericidal efficacy of the drug combination is sufficiently potent to eradicate bacteria from the infected dentine of root canals.
[Anaphylactoid purpura: intestinal ultrasonographic findings].
We evaluated six children with anaphylactoid purpura for ultrasonographic changes in the small intestine. Of 16 ultrasonographic scans, eight showed abnormal findings, consisting of circumscribed hypo-echoic enlargement, reduced peristalsis, equivocal structure of the small intestinal wall and ascites in patients with abdominal pain. Follow-up ultrasonography after steroid therapy demonstrated the small intestine to be normal in four of six patients. We believe that ultrasonography is an useful diagnostic modality to detect changes in the small intestinal wall in anaphylactoid purpura and plays an important role in its differentiation from other causes of abdominal pain.
[Unknown fever and abnormal liver functions after repeated epidural blocks with lidocaine for management of herpes zoster pain].
We present a case of unknown fever and abnormal liver functions which developed during the course of pain management for herpes zoster with repeated epidural blocks with 0.5% lidocaine 10 ml. The patient was a 67 year old woman. At her first admission to dermatology, there were no abnormal findings in her blood examinations. She complained of severe pain from herpes zoster. She was admitted to the pain clinic. She received thoracic epidural blocks with 0.5% lidocaine 10 ml repeatedly three or four times a week. Two weeks later, she developed general fatigue, appetite loss, nausea and a high fever. Blood examinations revealed the elevation of glutamic oxalacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), alkaline phosphatase (ALP), and gamma glutamyltrans peptidase (gamma-GTP), C reactive protein (CRP), and blood sedimentation rate (BSR). Many examinations including abdominal and thoracic computer tomography and abdominal echograph could not reveal the cause of high fever and abnormal blood examinations. We continued the thoracic epidural block for her herpes zoster pain. GOT, GPT, ALP, and gamma-GTP gradually went down to normal values in next two weeks, though fever still persisted. At this time, lymphocyte cell simulation test with 0.5 % lidocaine was positive and eosinophylic cell had increased to 5%. After ceasing the epidural block, fever resolved and blood examinations returned to normal values. These findings suggest strongly that 0.5% lidocaine induced fever and hepatitis.
Eubacterium saphenum sp. nov., isolated from human periodontal pockets [corrected].
A new species, Eubacterium saphenum [corrected] sp. nov., established on the basis of the results of DNA-DNA hybridization, was proposed for strains isolated from human periodontal pockets. Differential characteristics are given.
In vitro antimicrobial susceptibility to combinations of drugs on bacteria from carious and endodontic lesions of human deciduous teeth.
The purpose of this study was to clarify the antibacterial efficacy of mixed antibacterial drugs on bacteria of carious and endodontic lesions of human deciduous teeth in vitro. The antibacterial drugs used in this study were mixtures of ciprofloxacin, metronidazole, plus a third antibiotic: amoxicillin, cefaclor, cefroxadine, fosfomycin or rokitamycin. Samples taken from carious dentin (17 cases) and infected pulpal tissues (14 cases) were cultured on control plates and plates containing the mixed drugs. No bacteria were recovered in the presence of any combination of the mixture of the drugs (100 micrograms each/ml), and the bacterial growth occurred on control plates (10(1) to 10(7) colony-forming units), indicating that the mixed drugs inhibit the growth of bacteria in the samples. When carious and endodontic lesions on split surfaces of freshly extracted teeth were covered overnight with alpha-tricalcium phosphate cement containing a mixture of ciprofloxacin, metronidazole and cefaclor (1% each; 5 cases), no bacteria were recovered from the lesions. No bacteria were recovered from carious and endodontic lesions when these lesions were immersed in a solution of the mixture (200 micrograms each/ml; 5 cases). These findings indicate that carious and endodontic lesions can be sterilized by the mixed drugs in situ.
[Obstetric anesthesia in Gifu].
Improvement of perinatal mortality rate in Japan is remarkable for the last two decades, but maternal mortality rate is still relatively high in comparison with the improvement of the perinatal mortality rate. Maternal mortality rate 1991 in Japan was 8.5. Maternal deaths occurred mostly in perinatal period. The causes of death include pre- and postpartum hemorrhage, pulmonary embolism, and hypertension. This means an intensive, vigorous therapy including anesthesia management is necessary during peripartum period. Questionnaires were mailed to 63 maternity clinics in Gifu area. Some of the questions requested as many answers as applicable. We received 51 replies to questionnaires. Average Cesarean rate in Gifu was 7.3%. Spinal anesthesia was used in 74.5% of maternity clinics. Dibucaine was the most widely used local anesthetic for spinal anesthesia. Antacid medications were rare in our study group. After induction of general anesthesia, airway was maintained by masks (36.0%) or endotracheal tube (64.0%). Obstetric analgesia by local anesthetics was not used widely.
Predominant obligate anaerobes in human periodontal pockets.
This study was carried out to investigate the predominant anaerobic bacteria of periodontal pockets in patients with advanced periodontitis, who had no previous treatment other than supragingival scaling, no history of recent or chronic systemic illness, nor any intake of antibiotics within 6 weeks prior to bacteriological sampling. Care was taken not to ignore tiny-colony-forming anaerobes, by means of a stereoscope and an anaerobic glove box system. Out of 422 (100%) isolates, 380 (90%) were obligate anaerobes, suggesting that the environment in periodontal pockets was anaerobic and favors the growth of obligate anaerobes. Among the 380 obligate anaerobes isolated, strains belonging to Eubacterium (54%) were predominant, and many of them occurred in tiny colonies. The other obligate anaerobes isolated were assigned to Wolinella (9%), unidentified motile rods which resemble Wolinella (7%), Peptostreptococcus (6%), Fusobacterium (5%), Bacteroides (2%; including those reclassified to Prevotella and Porphyromonas) and Selenomonas (0.5%). Among the isolates, 67% were Gram-positive bacteria, including 59% of rods (mostly asaccharolytic Eubacterium), suggesting that these bacteria, particularly strains of the Eubacterium species, may play an important role in etiology of adult periodontitis.
Acute effect of hypobaria and hypoxia on renal nerve activity in anaesthetized rabbits.
To determine the acute effect of reduced barometric pressure and hypoxia on renal nerve activity, urethane-anaesthetized and mechanically ventilated rabbits were randomly exposed to the following four separate conditions in a decompression chamber: hypoxic hypobaria (n = 7), hypoxic normobaria (n = 5), normoxic hypobaria (n = 8) and slow normoxic hypobaria (n = 7). A combination of rapid decompression and simultaneous adjustment of inspired PO2 was used to simulate an altitude of 6600 m, and renal nerve activity and haemodynamics, such as systemic blood pressure and heart rate, were measured. During both hypoxic hypobaria and hypoxic normobaria, there were significant and similar increases in renal nerve activity at 6600 m (54 +/- 7% and 61 +/- 13% from each baseline, respectively). However, there were no changes in renal nerve activity during normoxic hypobaria or slow normoxic hypobaria with decompression rates of 1000 or 400 m min-1, respectively. From these results, we conclude that a reduction in barometric pressure without hypoxia does not affect renal nerve activity in anaesthetized rabbits.
Interaction of antisense DNA with nucleic acids/proteins.
In order to study interaction of various types of labeled antisense DNAs were prepared. Fluorescein and 2,2,6,6-tetramethypiperidine-N-oxyl were the label molecules, which were introduced to 5'-end of oligonucleotides and their analogs. Interactions of labeled antisense DNAs with nucleic acids or proteins such as HSA, HIG and TF, were studied by UV, fluorescence depolarization spectroscopy, and ESR spectroscopy. Hybrid formation of antisense DNAs with oligonucleotides in solution could be monitored by the increase in fluorescence anisotropy (r) and by intensity change in ESR spectra. When phosphorothioate type antisense molecules anchoring fluorescein (F-OPT) were mixed with proteins, r drastically increased, whereas ODN slightly increased. These results suggest that OPTs have much more affinity for proteins than ODNs.
Bronchospasm-induced massive lung collapse during thoracotomy.
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