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Biomedical subjects

T Imamura

Publications and source records attributed to T Imamura.

At least 361 records · Page 20Linked to original sources
PubMed1994

Simultaneous determination of nicotine and cotinine in various human tissues using capillary gas chromatography/mass spectrometry.

A reliable and sensitive method for the simultaneous determination of nicotine and cotinine concentrations in various human tissues was developed using capillary gas chromatography/mass spectrometry. Nicotine and cotinine were extracted using a 3-step solvent extraction procedure and quinoline as an internal standard. Quantification was carried out by single ion monitoring using ions of m/z 133 for nicotine, m/z 176 for cotinine and m/z 129 for quinoline. The lower limit of detection was 5 ng/g for nicotine and 10 ng/g for cotinine, in each tissue sample. The calibration curves of various tissues were linear in the concentration range from 5-1,200 ng/g for nicotine and 10-1,500 ng/g for cotinine. The accuracy and precision of this method were examined using human tissues and the results were satisfactory. The distribution of nicotine and cotinine was measured in tissues from 10 human autopsies. Nicotine was detected in every tissue examined at a level seen in habitual smokers. The nicotine concentration was high in the liver, kidney, spleen and lung, and low in adipose tissue. The cotinine level was highest in the liver. The tissue/blood concentration ratios of nicotine and cotinine were most stable in skeletal muscle, where the level of these drugs was close to that in whole blood. Skeletal muscle is, therefore, considered to be the most suitable tissue sample for toxicological examination, when acquisition of blood samples is not feasible.

Adipose Tissue↗
PubMed1994

A case of appendiceal cancer metastatic to the stomach with pseudomyxoma peritonei.

Appendiceal cancer associated with pseudomyxoma peritonei is a low grade malignancy and its extraperitoneal metastasis is extremely rare. We report a case of gastric metastasis of this tumor in a 76-year-old man. Two metastatic gastric tumors, which appeared after a 1-year interval, were successfully resected endoscopically. The patient was well for more than 3 years after the onset of the disease. To our knowledge, gastric metastasis from appendiceal cancer with pseudomyxoma peritonei has not been previously reported.

Aged↗
PubMed1994

Recurrent pulmonary metastases from benign giant cell tumors of the bone: report of two cases and analysis of nuclear DNA content by flow cytometry.

It is impossible to predict the biological characteristics of benign giant cell tumors of the bone (BGCTB) from light microscopic findings. About 2% of patients with BGCTB develop pulmonary metastases and we encountered two such patients, both of whom underwent several pulmonary resections. The nuclear DNA content of the primary lesion, the locally recurrent lesion, and the pulmonary metastatic lesions were determined by flow cytometry. The tumors from both patients exhibited a diploid pattern without any of the biological characteristics of BGCTB such as latent activity or metastasis.

Adult↗
PubMed1994

Evidence that both Ca(2+)-ATPase and (Ca2+ + Mg2+)-ATPase activities in the plasma membrane-rich fraction from bovine parotid gland reside on the same enzyme molecule.

1. Evidence was obtained that activities of both low-affinity Ca(2+)-ATPase and high-affinity (Ca2+ + Mg2+)-ATPase in the plasma membrane-rich fraction from bovine parotid gland reside on the same enzyme. 2. Two solubilized ATPases were purified by four steps of HPLC; and both activities eluted at the same fractions from each column, and the specific activity ratio of the two enzymes at each step was constant. 3. By non-denaturing PAGE, the final preparation gave a single band for both protein staining and activity staining for the two ATPases; and the Ca(2+)-ATPase activity comigrated with that of (Ca2+ + Mg2+)-ATPase. 4. In SDS-PAGE, each activity staining for the ATPases also gave a single band, and both activities comigrated. 5. These findings suggest that Ca(2+)-ATPase and (Ca2+ + Mg2+)-ATPase are a single enzyme.

Animals↗
PubMed1994

Peak time difference of time-density curve in contrast media transit as an indicator of asymmetric cerebral perfusion.

Time-density curve study in contrast media transit has a theoretical possibility to evaluate asymmetric cerebral perfusion. We studied the right-to-left hemispheric difference of peak time in regional time-density curve. Twenty-seven chronic stroke patients underwent either dynamic CT or intravenous digital subtraction angiography (IVDSA), and single photon emission CT (SPECT). We placed symmetric regions of interest as appropriate in each study, and obtained a peak time of each regional time-density curve in IVDSA or dynamic CT, and a laterality index of reconstructed counts in SPECT. Right-to-left difference of peak time significantly correlated to the laterality index both in IVDSA and dynamic CT (r = -0.88, p < 0.001, and r = -0.82, p < 0.001, respectively). Thus, time-density curve study well reflected unilateral reduction of cerebral perfusion. Recent progress in acute thrombolytic intervention for ischemic stroke recommends a quick and efficient evaluation of ischemic status, and time-density curve study may satisfy this requirement.

Angiography, Digital Subtraction↗
PubMed1994

Genetic origin of malignant trophoblastic neoplasms.

The genetic origin of three trophoblastic neoplasms (two choriocarcinomas and a placental site trophoblast tumor (PSTT)] was determined by analysis of the restriction fragment length polymorphism (RFLP) pattern. One choriocarcinoma, which was believed not illogically to have developed from an antecedent complete mole, contained both paternal and material RFLP alleles and thus was probably the product of a normal fertilization. The other choriocarcinoma was not of gestational origin but had RFLPs homozygous at some loci and heterozygous at others, compatible with the parthenogenic origin of this tumor from a germ cell after meiosis I. The PSTT required amplification of DNA sequences by polymerase chain reaction (PCR) because of the small amount of tumor material available. This tumor contained RFLP alleles from both parents and appeared to have resulted from a previous unrecognized (and abnormal) pregnancy.

Adult↗
PubMed1994

Immunohistochemical study of heparan sulfate proteoglycan in adenocarcinomas of the pancreas.

The prognosis for carcinoma of the pancreas is extremely poor. One of the characteristics of this tumor is its invasion of the surrounding tissues. Reduction of glycoprotein is considered to be conducive to invasion of the basement membrane by carcinoma cells. Heparan sulfate proteoglycan (HSPG), a kind of glycoprotein, is an important component of basement membrane. In this study, the relation between HSPG and carcinoma of the pancreas was examined by using the immunohistochemical method, and the survival rate of pancreatic adenocarcinoma was evaluated. We found that some carcinomas contained little or no HSPG. The poorer the differentiation of an adenocarcinoma of the pancreas, the lower was its content of HSPG. The level of HSPG was significantly different in carcinomatous and in noncarcinomatous cells. There was a close correlation among the content of HSPG, the degree of differentiation of carcinomas of the pancreas, and the survival time. HSPG seems to be useful in prognosis of adenocarcinoma of the pancreas.

Adenocarcinoma↗
PubMed1994

Long-term follow up in type A insulin resistant syndrome treated by insulin-like growth factor I.

Insulin-like growth factor I (IGF-I) is a useful therapeutic agent in insulin resistant diabetes mellitus due to insulin receptor disease because of its hypoglycaemic effects through the IGF-I receptor. A girl with typical type A insulin resistant syndrome was treated with IGF-I for two years and the treatment was effective in ameliorating hyperglycaemia. Overproduction of testosterone in polycystic ovaries was aggravated with this treatment, however. Therefore, IGF-I treatment may be used for glycaemic control but with caution because of its possible side effect of aggravating hyperandrogenism in these patients.

Acanthosis Nigricans↗
PubMed1994

Transforming growth factor beta 1 as a prognostic factor in pulmonary adenocarcinoma.

AIMS: To evaluate the efficacy of transforming growth factor beta (TGF-beta) for the prognosis of pulmonary adenocarcinoma. METHODS: TGF-beta was detected immunohistochemically using the avidin-biotin-peroxidase complex technique in resected pulmonary adenocarcinomas from 88 patients. RESULTS: Of the 88 patients, 39 were TGF-beta negative and 45 TGF-beta positive. The five year survival rate was 56% for the TGF-beta negative and 16% for the TGF-beta positive group. CONCLUSIONS: TGF-beta can be used as a prognostic factor in pulmonary adenocarcinoma.

Adenocarcinoma↗
PubMed1994

Platelet-activating factor involvement in the aggravation of acute pancreatitis in rabbits.

Platelet activating factor (PAF) was administered to anesthetized rabbits with cerulein-induced acute pancreatitis to investigate the role of PAF in the development of acute pancreatitis. In acute edematous pancreatitis, induced with cerulein 20 micrograms/kg/h i.v. for 5 h, blood flow in the gastroduodenal and superior mesenteric arteries (GDAF and SMAF) had decreased significantly by 30 min and the serum amylase and lipase levels were significantly increased in the early phase. In the cerulein+PAF group, in which PAF was injected 100 ng/kg/min i.v. for 20 min simultaneously with cerulein, GDAF and SMAF declined significantly to 52 +/- 4 and 47 +/- 3% (p < 0.05), serum amylase and lipase levels rose significantly to 1,110 +/- 150 and 1,370 +/- 190% (p < 0.01) at 300 min, much higher than in the cerulein group. Furthermore, scattered hemorrhages and more marked inflammatory cell infiltration were observed histologically. These findings suggest that PAF has an additive role in the aggravation of acute pancreatitis.

Acute Disease↗
PubMed1994

Acute changes in myosin heavy chain synthesis rate in pressure versus volume overload.

The left ventricular hypertrophy that develops with the volume overload of mitral regurgitation is relatively less than that which develops with the pressure overload of aortic stenosis even when both lesions are severe. The hypertrophy that develops must be the sum of changes in the rate of myocardial protein synthesis and degradation. In the present canine study, we explored early changes in the synthesis rate of myosin heavy chain in response to severe acute pressure overload versus that of the severe acute volume overload of mitral regurgitation. We tested the hypothesis that in acute overload, the rate of protein synthesis would increase less in the volume-overload model than in the pressure-overload model, a potential partial mechanism for the discrepancy in the eventual total amount of hypertrophy that develops in these two lesions. Acute pressure overload was produced by inflating a balloon in the descending aorta, and acute volume overload was produced by using our closed-chest mitral chordal rupture technique. In both models, the hemodynamic lesion that was created was severe. In eight dogs with pressure overload, the average gradient across the balloon was 119.8 +/- 6.1 mm Hg. In six dogs with volume overload, the average regurgitant fraction was 0.67 +/- 0.06. Six other dogs served as controls. The average rate of myosin heavy chain synthesis in control dogs was 2.7 +/- 0.2% per day, virtually identical to the rate we found in the severe volume-overload model. In contrast, the rate was increased in the pressure-overload model by 30% to 3.5 +/- 0.3% per day (P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1994

The role of proteolytic enzymes in the development of pulmonary emphysema and periodontal disease.

Pulmonary emphysema and periodontal disease are each characterized by the uncontrolled proteolysis of connective tissue proteins by proteinases derived from human neutrophils. Although these diseases would not appear to be related in terms of the initial insult to individual tissues, the ultimate result in each disease is the accumulation and degranulation of neutrophils at inflammatory sites, apparently as a result of frustrated phagocytosis and specific activation of these phagocytic cells. This result is easily recognized in the case of emphysema, where there is clear evidence that the primary cause of the disease is the accumulation of foreign materials in the lung (e.g., smoke condensate), followed by the recruitment of neutrophils to the organ and the release of oxidative and hydrolytic enzymes. In periodontitis, however, the problem begins with the accumulation of plaque at the base of the teeth, followed by the growth of opportunistic anaerobic bacteria below the gum line. These parasitic microbes, which are resistant to killing by both monocytes and granulocytes, secrete proteinases that can activate the kallikrein-kinin pathway, degrade clotting factors, and release the potent neutrophil chemotactic factor, C5a, from complement. It is under such conditions that neutrophils are recruited to infected sites within the periodontium. After the neutrophil-recruitment stage, the two diseases become similar in that degranulation of neutrophils occurs during attempted phagocytosis of either cigarette smoke components (emphysema) or bacteria (periodontitis), followed by inactivation of tissue proteinase inhibitors and degradation of connective tissue proteins, the ultimate result being the destruction of the alveolus or gingiva, respectively.

Animals↗
PubMed1994

Pathogenesis of periodontitis: a major arginine-specific cysteine proteinase from Porphyromonas gingivalis induces vascular permeability enhancement through activation of the kallikrein/kinin pathway.

To elucidate the mechanism of production of an inflammatory exudate, gingival crevicular fluid (GCF), from periodontal pockets in periodontitis, we examined the vascular permeability enhancement (VPE) activity induced by an arginine-specific cysteine proteinase, Arg-gingipain-1 (RGP-1), produced by a major periopathogenic bacterium, Porphyromonas gingivalis. Intradermal injections into guinea pigs of RGP-1 (> 10(-8) M), or human plasma incubated with RGP-1 (> 10(-9) M), induced VPE in a dose- and activity-dependent manner but with different time courses for the two routes of production. VPE activity induced by RGP-1 was augmented by kininase inhibitors, inhibited by a kallikrein inhibitor and unaffected by an antihistamine drug. The VPE activity in human plasma incubated with RGP-1 also correlated closely with generation of bradykinin (BK). RGP-1 induced 30-40% less VPE activity in Hageman factor-deficient plasma and no VPE in plasma deficient in either prekallikrein (PK) or high molecular weight kininogen (HMWK). After incubation with RGP-1, plasma deficient in PK or HMWK, reconstituted with each missing protein, caused VPE, as did a mixture of purified PK and HMWK, but RGP-1 induced no VPE from HMWK. The VPE of extracts of clinically isolated P. gingivalis were reduced to about 10% by anti-RGP-1-IgG, leupeptin, or tosyl-L-lysine chloromethyl ketone, which paralleled effects observed with RGP-1. These results indicate that RGP-1 is the major VPE factor of P. gingivalis, inducing this activity through PK activation and subsequent BK release, resulting in GCF production at sites of periodontitis caused by infection with this organism.

Adhesins, Bacterial↗
PubMed1994

Formaldehyde-fixed cells infected with pseudorabies virus conferred resistance against Aujeszky's disease.

Cells infected with Pseudorabies virus (PrV) and fixed with formaldehyde were evaluated as a vaccine against Aujeszky's disease. Mice and pigs inoculated with fixed cells showed no clinical signs. In a challenge test, all fixed cells conferred protection on mice and pigs. Although pigs showed slight symptoms, they were restored to normal health within a few days. These results demonstrate that PrV-infected cells fixed with formaldehyde function as a vaccine against Aujeszky's disease and serve as a novel type of vaccine which is easy to make, and is both safe and effective.

Animals↗
PubMed1994

[Age-related changes in the visual function of WBN/Kob rats--an electrophysiological study].

Changes in the visual function of the male WBN/Kob rat known as diabetic strain with increasing age were studied electrophysiologically. The measurements of electroretinogram (ERG) and visual evoked potential (VEP) in male WBN/Kob rats were performed at 5, 9, 13, 17, 23, 27, 36, 45, 54, 67 and 80 weeks of age, and compared with those in male Wistar/ST rats used as control. The prolonged latencies and decreased amplitudes of a- and b- waves and oscillatory potentials of ERG in WBN/Kob rats aged over 17 or 27 weeks were recorded under the light or after 20 min dark adaptation. The visual abnormality as indicated by non-recordable ERG was obvious in WBN/Kob rats aged 67 and 80 weeks. No changes of N1, P and N2 peak latencies of VEP were recorded in WBN/Kob rats with increasing age. The amplitudes between N1 peaks and P peaks decreased remarkably in WBN/Kob rats aged 54 weeks. The amplitudes of VEP in 67 or 80 weeks old rats in which ERG disappeared showed 26 or 28% of those in 5 weeks old rats. From these results, recording of ERG and VEP suggested that the visual abnormality occurred in male WBN/Kob rats aged 67 or 80 weeks and the process of visual abnormality with increasing age was clarified.

Aging↗
PubMed1994

Age-related changes in the visual organ of WBN/Kob rats--an ophthalmoscopical study.

Changes in the visual organ with aging were investigated non-surgically in male WBN/Kob rats, in which spontaneous diabetic mellitus commonly occurs. Male Wistar/ST rats at the ages of 5, 9, 13, 17, 23, 27, 36, 45, 54, 67 and 80 weeks were examined for changes in the peri-orbital region, eyelid, lens, corpus vitreum and ocular fundus by macroscopic inspection and fundoscopy. The area around the eyelid was stained with reddish-brown excretions from the Harderian gland. This stain was frequently observed in rats of both strains aged 54 weeks or over, showing no difference in frequency between WBN/Kob rats and Wistar/ST rats. Lens opacity was observed in male WBN/Kob rats aged 67 weeks or over, and narrowing of the retinal artery and vein in those aged 36 weeks or over. The occurrence of lens opacity was consistent with that of visual dysfunction as determined by a test of the ability to differentiate light from dark using a Y-shaped apparatus (Kiyosawa et al., 1993).

Aging↗