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Biomedical subjects

J Shimada

Publications and source records attributed to J Shimada.

At least 145 records · Page 8Linked to original sources
PubMed1992

Effect of antacid on absorption of the quinolone lomefloxacin.

The effect of antacid on the absorption of lomefloxacin (LFLX) in humans was studied. When LFLX was orally administered concomitantly with aluminum- and magnesium-containing antacids under fasting conditions, its level in plasma decreased by one-half and its area under the concentration-time curve was reduced by 40% compared with the levels observed after treatment with LFLX alone. The urinary recovery value also decreased by 40%. No such effects were noted after coadministration of LFLX and a nonmetallic antacid. This study confirmed the existence of chelate complexes of LFLX with Al3+ and Mg2+ and examined the chelating strength. The stability constants of LFLX with Al3+ and Mg2+ were measured and compared with those of ofloxacin and norfloxacin; little difference was observed among them. LFLX was found to bind more strongly with Al3+ than with Mg2+. Further, the existence of chelate formation was proven by 13C-nuclear magnetic resonance spectroscopy. The decrease in the LFLX level in plasma in humans could be explained by a reduced absorption of the Al(3+)- and Mg(2+)-LFLX chelate complexes.

Adult↗
PubMed1992

Effect of probenecid on the pharmacokinetics of DQ-2556, a new 3-quaternary ammonium cephalosporin antibiotic, in humans.

A total of 5 healthy volunteers were enrolled in a crossover study on the dose dependency and the effect of probenecid on pharmacokinetics of DQ-2556. They were administered intravenously 0.5 and 1.0 g of DQ-2556, and 1.0 g of DQ-2556 with oral administration of probenecid. The linearity in pharmacokinetics of DQ-2556 was confirmed up to the dose of 1.0 g. In the case of 1.0 g of DQ-2556 with probenecid treatment, the area under the serum concentration-time curve was larger, and total and renal clearances were less than those in the case of 1.0 g of DQ-2556 alone (by approximately 15% for each parameter, p < 0.01). These results demonstrated that DQ-2556 is secreted in the renal tubule, although it is excreted mainly by the glomerular filtration.

Administration, Oral↗
PubMed1992

[Transarterial "pile-up" infusion therapy of cisplatin and lipiodol emulsion in hepatic malignancies without TAE (transcatheter arterial embolization)].

We developed a modified transcatheter arterial infusion method using anticancer agents to treat hepatic malignancies; intermittent injections of iodized oil, lipiodol, containing adriamycin or epirubicin during the arterial infusion of cisplatin (75-200 mg/body) in order to achieve a higher concentration and longer retention of these anticancer agents in the tumor tissue. Fourteen patients with hepatocellular carcinoma (HCC) and five patients with metastatic liver cancer were treated with this "pile-up" arterial infusion therapy by anticancer agents without gelatin sponge TAE. In HCC patients, 50% or greater reduction in tumor size was obtained in 7 of 14 patients (50%). Serum AFP levels decreased by more than 75% in 6 of 7 patients in whom pretreatment serum levels of AFP were more than 200 ng/ml. The one-year and two-year survival rates were estimated at 55% and 27.5%, respectively, by the Kaplan-Meier method. Significant reduction in tumor size was not observed in 5 cases with metastatic liver cancer. Concerning the adverse effects, alimentary symptoms and fever were noted for a few days in many cases, but they were temporary and tolerable in almost all of the patients. Severe adverse changes in laboratory data were not observed. Thus this "pile-up" infusion therapy of anticancer agents without TAE may be a useful therapy for HCC.

Adult↗
PubMed1992

A comparative study on the convulsant activity of carbapenems and beta-lactams.

Beta-lactams are well known to have potent convulsant activity. Imipenem, the first carbapenem antibiotic introduced in the clinical field, has been reported to induce convulsions. The neurochemical mechanism of the convulsions induced by carbapenems and cephalosporins were studied. Intraventricular injection of cefazolin, cephaloridine and imipenem, and of panipenem (a new carbapenem), induced convulsions in a dose-dependent manner in mice. They inhibited the receptor binding of gamma-aminobutyric acid (GABA), an inhibitory transmitter in the mammalian central nervous system. These in-vitro and in-vivo results suggest that carbapenems and cephalosporins might induce convulsions through the inhibition of GABA receptor binding when they are accumulated in the central nervous system.

Animals↗
PubMed1992

Adverse effects of fluoroquinolones.

The newer fluoroquinolones have various kinds of adverse reactions and drug-drug interactions. Patients given concurrent therapy of fluoroquinolones with theophylline should be carefully observed. It is better to avoid concurrent therapy of fluoroquinolones with NSAIDs, and patients given fluoroquinolones who have a history of central nervous system disorders should be put under careful observation, because of the possibility of central nervous system reactions. Fluoroquinolones should be carefully administered to patients with compromised renal functions, because fluoroquinolones are accumulated in patients with impaired renal function. Although fluoroquinolones have various kinds of adverse reactions, the frequency of toxicity is considered to be acceptable. However careful, clinical and experimental studies should be continued to reveal more details on the adverse reactions of fluoroquinolones.

4-Quinolones↗
PubMed1991

[Kinetic estimation of infused Lipiodol within a hepatoma using a CT dynamic study].

Distribution of Lipiodol within hepatic tumor was evaluated using serial computed tomography. Imagistic Lipiodol transition into the tumor via hepatic artery was slower than that of water soluble contrast medium, spreading to central part first and turn to peripheral part of the tumor. This method was thought to be useful to clarify Lipiodol distribution in hepatic tumor and to decide the method or necessity of additional trans-arterial therapy.

Aged↗
PubMed1991

Effects of enoxacin and its combination with 4-biphenylacetate, an active metabolite of fenbufen, on population spikes in rat hippocampal slices.

The effects of enoxacin, a new quinolone antibacterial agent, and its combination with 4-biphenylacetate (BPA), an active metabolite of the non-steroidal antiinflammatory agent fenbufen, were examined on population spikes induced by electrical stimulation of the stratum radiatum in the CA1 pyramidal cell layer in rat hippocampal slices. Enoxacin (10(-4) M) and bicuculline (10(-6) M) increased the amplitude of the population spikes and anew elicited the second spikes (latency: 10 msec.), while BPA (10(-5) M) decreased the amplitude of the population spikes. However, the combination of enoxacin (10(-6), 10(-5) M) with BPA (10(-5) M) elicited the second spikes or epileptiform bursts with an increase of the population spike amplitude. The dose-response relationships showed that the effect of enoxacin was 100 times potentiated in the presence of BPA (10(-5) M). The second spikes induced by enoxacin (10(-4) M) were suppressed by muscimol (10(-6) M) and baclofen (10(-6) M), but not by clorazepate (5 x 10(-5) M) and pentobarbital (5 x 10(-5) M). The second spikes induced by bicuculline (10(-6) M) were suppressed by these four drugs. The second spikes by the combination of enoxacin (10(-6) M) with BPA (10(-5) M) were suppressed by muscimol (5 x 10(-6) M), but not by clorazepate (5 x 10(-5) M). These results suggest that the combination of enoxacin with BPA exerts a drug interaction to elicit the second spikes or epileptiform bursts with its mode of action different from that of bicuculline.

Action Potentials↗
PubMed1990

Differentiation of bronchogenic carcinoma from secondary changes, obstructive pneumonitis and/or collapse by I-123 IMP lung imaging.

Serial lung images with N-isopropyl-p-[I-123]-iodoamphetamine (I-123 IMP) were obtained to assess the imaging findings and to clarify the lesion to uptake relationships in 74 lesions in 73 patients with various histological types of bronchogenic carcinoma. A decreased uptake area was observed in all 74 lesions in the initial one or two-min I-123 IMP image. The initial image was analogous to a Tc-99m MAA lung perfusion image in 70 patients in whom both lung imaging procedures were performed. The imaging findings changed following this initial phase. At 4 hr, the lesion was depicted as either areas of decreased uptake or increased uptake or a combination of the two. Comparison between the lesion findings in the 4-hr I-123 IMP images, radiograms and removed specimens revealed that areas of decreased uptake corresponded to the cancerous portions of the lung mass or pleural effusion and areas of increased uptake corresponded to inflammatory portions including obstructive pneumonitis and/or collapse. Thus, the 4-hr I-123 IMP lung images can be used to discriminate the cancerous portion from associated secondary changes, obstructive pneumonitis and/or collapse.

Adenocarcinoma↗
PubMed1990

[Clinical courses and pathological findings in two gay male patients with acquired immunodeficiency syndrome infected in Japan].

This is a report on the clinical courses and pathological findings in two gay male patients with acquired immunodeficiency syndrome (AIDS) infected in Japan. Case 1. A 39 year-old Japanese homosexual male was diagnosed as amebic dysentery complicated with liver abscess on admission. He was placed on Metronidazole with complete relief. Serological tests was positive for AIDS. On second admission, he was found to have pneumocystis carinii pneumonia (PCP) and cytomegalo-viral uveitis. Administration of Pentamidine was partially effective, however the therapy with Azidothimidine was discontinued by bone marrow suppression. On his third admission, he suffered from cryptococcal meningitis and therapy-resistant fungusemia. Finally he died of recurrent pneumonia regardless of appropriate therapies. Autopsy proved extended cryptococcal infection in the brain, meninx, lungs, liver and kidney, and cytomegalo-infection in the lungs, liver and kidney. Furthermore, atypical mycobacteriosis was found in the lymph nodes. There was no active findings compatible with PCP. Case 2. A 44 year-old Japanese homosexual male was admitted with oral candidiasis and diagnosed as AIDS related complex. He suffered from pneumonia with marked improvement on sulfamethoxazole-Trimethoprim. On his second admission, he developed diarrhea and was found to be infected with Giardia lambia. In addition, cytomegalo-viral infection damaged his eye sight. He died of pneumonia and meningitis shortly there after. Autopsy proved a cytomegalo-viral infection in the lung and colon, old lesions possibly caused by PCP in the lungs, and suppurative meningitis in the meninx. These experiences confirm that AIDS patients can be exposed to several opportunistic infections at the same time in the multiple organs. Furthermore, it is suggested that homosexual patients with AIDS may have unique opportunistic infections such as amebic dysentery or Giardia lamblia unlike other AIDS patients related to hemophilia.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Renal handling of fleroxacin in rabbits, dogs, and humans.

The renal handling of fleroxacin was studied by renal clearance and stop-flow techniques in rabbits and dogs and by analyzing the pharmacokinetics with and without probenecid in humans. In rabbits the excretion ratios (fleroxacin intrinsic renal clearance/glomerular filtration rate) were greater than unity (2.01) without probenecid and were decreased to a value below unity (0.680) with probenecid. In dogs, on the other hand, the excretion ratios were less than unity (0.608 and 0.456) both without and with probenecid, and so were not affected by probenecid. This fact suggested that fleroxacin was excreted into urine by both glomerular filtration and renal tubular secretion in rabbits, but only by glomerular filtration in dogs, accompanied by partial renal tubular reabsorption in both species; these mechanisms were also supported by stop-flow experiments. In humans probenecid treatment induced increases in the elimination half-life and area under the serum concentration-time curve and decreases in apparent serum clearance, renal clearance, and urinary recovery of fleroxacin. The excretion ratio without probenecid was 1.13, which was significantly decreased to 0.750 with probenecid. These results indicated that both renal tubular secretion and reabsorption contributed to renal excretion of fleroxacin in humans. The contribution of tubular secretion was species dependent and was extensive in rabbits, minimal in dogs, and moderate in humans. Renal tubular reabsorption was commonly found in every species. The long elimination half-life of fleroxacin in humans might be explained by its small total serum clearance and small renal clearance, which are attributed to less tubular secretion and more tubular reabsorption.

Adult↗
PubMed1990

[Variations in blood cholinesterase activity and exposure to chlorpyrifos in termite-control workers].

Chlorpyrifos, an organophosphate insecticide, has often been used as a termite-control agent since the advent of regulatory measures against the use of chlordanes in September 1986. A current concern is hazards such as organophosphorus poisoning among termite-control workers. In this study, the blood cholinesterase activity, the number of hours engaged in termite-control work, general conditions, and various test values were examined regularly in eight workers at a termite-control office. The results are summarized as follows. 1. The plasma cholinesterase level was within the normal range from October 1986 until April 1987 in all workers, but started decreasing after May following the initiation of the full-scale termite-control season. It remained lower than the normal range (0.6 pH) from June until August in five of the six termite-control workers. The lowest level observed during this period was less than 50% of the mean value for each worker prior to the busy season in the six termite-control workers and was less than 10% of the pre-season values in three of them. In two workers, engaged mainly in sales, the plasma cholinesterase activity remained higher than in termite-control workers throughout the season. The lowest level in this minimally-exposed group during this period was not less than 50% of the mean value for each worker before the busy season. With the arrival of the off season, the level began to recover and returned to normal in all workers in January 1988. 2. The red cell cholinesterase activity remained within the normal range throughout the observation period, but it was generally low during the busy season from June to September and relatively high during the off season from December 1987 to January 1988. On the average, the red cell cholinesterase activity during the season was about 30% lower than that in the off season. 3. No marked subjective or objective abnormalities were seen in the workers. The results of other tests were generally normal, although a slight decrease in the red cell and white cell counts as well as abnormalities in serum lipid and lipase were noted in some workers. Further observations are necessary. 4. A significant negative correlation was noted between the number of hours engaged in termite-control work and variations in the plasma cholinesterase activity.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

[Influence of change in dental chair position on circulation kinetics. 1. Effects on rate x pressure product].

The rate x pressure product is a product of the systolic blood pressure and heart rate and is widely used in clinical medicine as an index of the cardiac oxygen supply-demand balance. Employing 20 healthy male subjects, we studied the changes in the rate x pressure product due to a body position change from the sitting position to the supine position in a dental chair. The following results were obtained: 1. The change from the sitting position caused a 10% decrease in the rate x pressure product, and this value did not return to the initial sitting position value even after 5 min in the supine position. 2. The heart rate tended to decrease due to the position change. 3. Immediately after the position change, the systolic blood pressure decreased significantly (p less than 0.05), but it tended to return to the initial value with the lapse of time. The lower rate x pressure product in the supine position suggests that the supine position is more advantageous than the sitting one in treatment of the elderly and patients with cardiovascular diseases from the viewpoint of the systemic cardiovascular kinetics.

Blood Pressure↗
PubMed1990

[Report on clinico-pathological examinations in Meikai University (formerly Josai Dental University) Hospital (4)].

This clinico-pathological study was conducted to examine biopsies and surgical specimens for histopathological diagnosis from April 1983 to March 1988 in Meikai University (formerly Josai Dental University) Hospital. The following statistical results were obtained: 1) The total number of the specimens examined was 2705, 2026 from the dental clinic and 679 from the medical clinic. 2) Concerning age distribution, most specimens from the dental clinic were from patients in the 40's age bracket, whereas most from the medical clinic were from those under 10 years of age. With regard to sex distribution, the difference between males and females was not so much in the dental clinic specimens, but the number from the medical clinic was greater for males than for females. 3) Concerning classification of the tumors from the dental clinic, 181 cases were benign; and of them 41 were odontogenic and 140 were non-odontogenic tumors. Among the odontogenic tumors, ameloblastoma, cementoma, and odontoma were the most numerous. Among non-odontogenic tumors, fibroma was the most common, followed by pleomorphic adenoma. Malignant tumors comprised 77 cases. Of them squamous cell carcinoma was the most commonly found, with the grade-2 type being most numerous. Of the medical clinic tumors, nevus was the most common benign tumor observed; and adenocarcinoma, the most common malignant one. 4) Concerning the distribution of main lesions in the dental clinic specimens, most specimens were cysts or cystic lesions, followed by inflammatory lesions and tumors. Among medical clinic specimens, inflammatory lesions were the most common. 5) Regarding the dental clinic specimens, the most frequently observed case was the radicular cyst (301 samples) among the odontogenic cysts (514 samples); and among non-odontogenic cysts (290 samples), the most common was the mucous cyst (159 samples). 5) In terms of the distribution by location, tissue or organ, most tumors from the dental clinic were from the jaws, followed in descending frequency by those from gingiva and alveolar mucosa, maxillary sinus, lip, buccal mucosa, and tongue. Among the medical clinic tumors, the paranasal cavity and tonsils were the most frequent locations.

Adult↗
PubMed1990

[Reconstruction of occlusal function with osseointegrated implant following mandibular resection].

We succeeded satisfactorily to restore the occlusal function by use of an osseointegrated implant following iliac bone grafting and partial mandibulectomy in 4 patients who underwent surgical resection of odontgenic cyst and benign or malignant tumor of the oral cavity. Case 1: The patient was a 19-year-old man. Partial resection of the mandible was carried out under the diagnosis of odontgenic keratocyst of the left lateral incisor to the 1st premolar region. Iliac bone grafting was performed as secondary surgery. After confirmation of the fusion of the grafted bone, the occlusal function was restored by use of an osseointegrated implant. Case 2: The patient was a 36-year-old man. After segmental resection of the mandible under the diagnosis of ameloblastoma of the left 2nd premolar to the right 2nd premolar region, mandibular reconstruction was carried out with an A-O plate. Iliac bone grafting was performed as secondary surgery. After fusion of the grafted bone had been confirmed, the A-O plate was remounted and the fixture was immediately implanted. Five months later, vestibuloplasty by free skin grafting and attachment of the abutment were carried out. A superstructure was mounted. Case 3: The patient was a 22-year-old woman. The histopathologically confirmed odontogenic myxoma in the right mandible posteriorly from the second premolar was resected. Immediate reconstruction of the mandible was carried out by use of an iliac bone graft. After confirmation of the fusion of the grafted bone, the occlusal function was restored by use of an osseointegrated implant. Case 4: The patient was a 57-year-old woman with carcinoma of the right lingual margin and mouth floor. The tumor was resected with the mandibular margin. Immediate reconstruction of the tongue and mouth floor with a major pectoral muscle skin flap was carried out. In the absence of evidence of recurrence, restoration of the occlusal function was attempted with an osseointegrated implant.

Adult↗
PubMed1990

Possibility for induction of convulsion by fleroxacin and its disposition in the central nervous system in animals.

Fleroxacin and its metabolites were examined for their possibility of the induction of convulsion in mice, inhibitory activity on GABA receptor binding, and disposition in the central nervous system of mice, rats and dogs. No convulsion was evoked in mice at high oral combination doses of fleroxacin and fenbufen. Brain-to-serum concentration ratios of fleroxacin after oral dose were 0.13 in mice, 0.19 in rats and 0.28 in dogs. Rats showed no accumulation of fleroxacin in brain and similar elimination from brain to that from serum after the oral dose. Dogs exhibited the similar distribution of fleroxacin into various brain regions. The inhibitory effect of fleroxacin on GABA receptor binding was relatively weak and slightly potentiated in the presence of 4-biphenylacetic acid. Demethyl fleroxacin showed more potent inhibitory activity on GABA receptor binding and potentiation with 4-biphenylacetic acid. The combination of intravenous demethyl fleroxacin and oral fenbufen showed no convulsion in mice. Fleroxacin N-oxide showed only slight inhibitory activity on GABA receptor binding, being not influenced with 4-biphenylacetic acid.

Animals↗
PubMed1990

[Effects of antacids on absorption, excretion and metabolism of cefteram pivoxil].

Effects of various antacids (sodium bicarbonate, aluminium hydroxide gel) and an H2-blocker (cimetidine) on the absorption and excretion of a new cephem drug for oral use, cefteram pivoxil (CFTM-PI), were studied in healthy adult volunteers. 1. No significant differences were found in serum levels of CFTM and CFTM-A (an inactive isomer of cefteram (CFTM)) or their urinary excretion levels (concentration, recovery rate) between the group given CFTM-PI in combination with sodium bicarbonate and that given CFTM-PI alone. 2. There were no significant differences in serum levels of CFTM and CFTM-A or their urinary excretion levels (concentration, recovery rate) between the group given CFTM-PI in combination with aluminium hydroxide gel and that given CFTM-PI alone. 3. In contrast, serum levels of CFTM and its urinary recovery rate were significantly less in the group given the drug in combination with cimetidine than in that given a single administration 2-3.5 hours and 2-4 hours after administration, respectively. Clinical considerations remain.

Absorption↗
PubMed1989

[The actual state of occupational exposure to chlorpyrifos of termite control workers].

Chlorpyrifos, an organophosphorus insecticide, has been used as a termite control agent since regulatory measures against the use of chlordane were taken in September, 1986. In this study the actual state of occupational exposure to chlorpyrifos of termite control workers was investigated. The findings obtained were as follows. The concentration of chlorpyrifos in the air (near the mouth) was about 10 times higher (1.7-2.3 mg/m3) under the floor than the threshold-limit value (0.2 mg/m3) proposed by the ACGIH and rose close to the threshold-limit value even above the floor. Regarding the performance of the absorption can of the mask, generally satisfactory results were obtained. The adhesion of this compound to the work outfit was conspicuous during the spraying work under the floor, and it was often noted on the right forearm (12 micrograms/cm2), on the left knee (10 micrograms/cm2), on the right knee (9 micrograms/cm2) and on the face (5 micrograms/cm2). The rate of this compound penetrating through the work outfit amounted to an average of 40 percent, making it clear that a considerable amount of the compound penetrated the work outfit. Furthermore, direct adhesion of the compound to the neck was considered. These results suggested the dermal-exposure to chlorpyrifos of termite control workers. This compound was detected, though the quantity was very small, in blood after work, which was definitely indicative of exposure at the time of termite control work. The plasma cholinesterase activity in the termite control workers was within the normal range before the busy termite control season but fell off markedly when the full-scale termite control season set in. It is suggested that a decrease in plasma cholinesterase activity occurs due to chlorpyrifos exposure.

Chlorpyrifos↗