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Biomedical subjects

J Han

Publications and source records attributed to J Han.

At least 235 records · Page 13Linked to original sources
PubMed1998

cGMP facilitates calcium current via cGMP-dependent protein kinase in isolated rabbit ventricular myocytes.

The effect of guanosine 3',5'-cyclic monophosphate (cGMP) on L-type Ca current (ICa) was investigated in a study of rabbit ventricular myocytes using the whole-cell patch-clamp technique. Intracellular application of cGMP (100 MUm) increased ICa in the absence of isoprenaline or forskolin. 8-Bromo-cGMP (100 muM) and 8-(4-chlorophenylthio)-cGMP (8-pCPT-cGMP, 400 muM), relatively specific stimulators of cGMP-dependent protein kinase (cGMP-PK), also increased ICa. The stimulatory effect of 8-pCPT-cGMP was suppressed by Rp-8-chlorophenylthio-cGMP (400 muM), a phosphodiesterase-resistant cGMP-PK inhibitor. When ICa was increased by bath application of the non-specific phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX, 100 muM), 8-pCPT-cGMP (400 muM) resulted in additional stimulation of ICa. In the presence of 8-pCPT-cGMP, additional applications of isoprenaline (1 muM) or forskolin (1 muM) induced a further increase in ICa. From these results, it could be concluded that the activation of cGMP-dependent protein kinase is involved in the facilitation of ICa by cGMP in rabbit ventricular myocytes.

1-Methyl-3-isobutylxanthine↗
PubMed1998

Surgical resection of mucoepidermoid carcinoma at the carina in a 9-year-old boy.

Mucoepidermoid carcinoma of trachea and bronchi is a rare tumor, especially in children. The authors report a case of 9-year-old boy with mucoepidermoid carcinoma at the carina. His presenting symptoms were hemoptysis of recent onset and intermittent cough of 2 years' duration. Preoperative assessment of the tumor was an intraluminal polypoid mass arising from the carina extending into the trachea and right main stem bronchus. A complete resection with reconstruction of carina was successful. The tumor was 12 mm in size, polypoid with a broad base. It had characteristic features of a low-grade mucoepidermoid tumor, namely, admixture of islands of intermediate cells and glandular components with invasion of submucosa. The patient is now 15 months postsurgery free of disease.

Bronchial Neoplasms↗
PubMed1998

The p38 MAP kinase pathway and its biological function.

p38 is a mitogen-activated protein (MAP) kinase with structural and functional characteristics that distinguish it from JNK and ERK MAP kinases. p38 activity is upregulated when cells are exposed to a variety of stimuli including bacterial pathogens, proinflammatory cytokines, certain growth factors, and other forms of environmental stress. By regulating downstream substrates that include protein kinases and transcription factors, p38 participates in transmission, amplification, and diversification of the extracellular signal, initiating several different cellular responses. Studies have revealed that activation of p38 pathway is related to many pathological changes that occur in the course of inflammatory/immunologic and cardiovascular diseases.

Journal Article↗
PubMed1998

Traditional and evidence-based acupuncture: history, mechanisms, and present status.

BACKGROUND: In 1983, the Southern Medical Journal advised its readers that a scientific basis might underlie the popular practice of ancient Chinese acupuncture. Recent studies have proven this to be correct, and a 1997 National Institutes of Health consensus panel recommended acupuncture as a useful clinical procedure. METHODS: Pertinent articles in the literature were reviewed, including our own research. Significantly, we had access to recent important studies from China. RESULTS AND CONCLUSIONS: Most of the 10,000 acupuncturists in the country today practice metaphysically explained "meridian theory" acupuncture using needles to supposedly remove blockages of a hypothesized substance "Qi." Scientific research has shown that healing is not by manipulating Qi but rather by neuroelectric stimulation for the gene expression of neuropeptides. Needles are not necessary. Evidence-based neuroelectric acupuncture requires no metaphysical rituals. It is a simple, useful clinical tool for pain modulation and other conditions and can be easily taught to physicians.

Acupuncture Therapy↗
PubMed1998

E1B 19,000-molecular-weight protein interacts with and inhibits CED-4-dependent, FLICE-mediated apoptosis.

Genetic studies of the nematode Caenorhabditis elegans (C. elegans) have identified several important components of the cell death pathway, most notably CED-3, CED-4, and CED-9. CED-4 directly interacts with the Bcl-2 homologue CED-9 (or the mammalian Bcl-2 family member Bcl-xL) and the caspase CED-3 (or the mammalian caspases ICE and FLICE). This trimolecular complex of CED-4, CED-3, and CED-9 is functional in that CED-9 inhibits CED-4 from activating CED-3 and thereby inhibits apoptosis in heterologous systems. The E1B 19,000-molecular weight protein (E1B 19K) is a potent apoptosis inhibitor and the adenovirus homologue of Bcl-2-related apoptosis inhibitors. Since E1B 19K and Bcl-xL have functional similarity, we determined if E1B 19K interacts with CED-4 and regulates CED-4-dependent caspase activation. Binding analysis indicated that E1B 19K interacts with CED-4 in a Saccharomyces cerevisiae two-hybrid assay, in vitro, and in mammalian cell lysates. The subcellular localization pattern of CED-4 was dramatically changed by E1B 19K, supporting the theory of a functional interaction between CED-4 and E1B 19K. Whereas expression of CED-4 alone could not induce cell death, coexpression of CED-4 and FLICE augmented cell death induction by FLICE, which was blocked by expression of E1B 19K. Even though E1B 19K did not prevent FLICE-induced apoptosis, it did inhibit CED-4-dependent, FLICE-mediated apoptosis, which suggested that CED-4 was required for E1B 19K to block FLICE activation. Thus, E1B 19K functions through interacting with CED-4, and presumably a mammalian homologue of CED-4, to inhibit caspase activation and apoptosis.

Adenovirus E1B Proteins↗
PubMed1998

Invasive pulmonary aspergillosis: prediction at thin-section CT in patients with neutropenia--a prospective study.

PURPOSE: To evaluate prospectively the usefulness of thin-section computed tomography (CT) in the prediction of biopsy-proved invasive pulmonary aspergillosis in patients with neutropenia. MATERIALS AND METHODS: In 11 consecutively seen neutropenic patients, 12 open-lung biopsies were performed prospectively for suspected angioinvasive (n = 10) or airway-invasive (n = 2) pulmonary aspergillosis. Thin-section CT findings in the patients with angioinvasive pulmonary aspergillosis were reviewed, and the findings were compared with those of other diseases. RESULTS: Five of 12 biopsy specimens were positive for angioinvasive pulmonary aspergillosis; none was positive for airway-invasive pulmonary aspergillosis. In five (50%) of 10 cases, suspicion of angioinvasive pulmonary aspergillosis proved to be correct. The most common CT findings were segmental areas of consolidation plus ground-glass attenuation (four of five cases [80%]) and at least one nodule surrounded by a halo (two of five cases [40%]). Segmental areas of consolidation plus ground-glass attenuation were seen as isolated findings in three and mixed findings with nodules that have a surrounding halo in one case. In two patients, at least one nodule with a halo was an isolated finding in one patient and a mixed finding in one patient. Mucormycosis, organizing pneumonia, and pulmonary hemorrhage produced similar findings. CONCLUSION: At thin-section CT, segmental areas of consolidation plus ground-glass attenuation or at least one nodule with the halo sign were seen in patients with invasive pulmonary aspergillosis. The findings were nonspecific, however, and can be seen in neutropenic patients with mucormycosis, organizing pneumonia, or pulmonary hemorrhage.

Adolescent↗
PubMed1998

Bronchial stenosis due to anthracofibrosis.

STUDY OBJECTIVES: To define the clinical characteristics of the patients showing bronchoscopic findings of bronchial narrowing or obliteration with black pigmentation on overlying mucosa (we named this finding as "anthracofibrosis"), and to determine the association of anthracofibrosis with tuberculosis. PATIENTS AND METHODS: The subjects of this study consisted of 28 patients; 8 men and 20 women, ranging in age from 42 to 86 years. The distinctive clinical features, natures of bronchoscopic lesions, and radiologic findings were analyzed retrospectively and summarized. Bacteriologic studies and results of pathologic examinations were also assessed. RESULTS: Chief complaints were cough (20/28) and dyspnea on exertion (17/28). The abnormal bronchoscopic findings were identified most frequently in the right middle lobe bronchus (n=21/28) while more than one part of the bronchial tree was narrowed in 22 patients. Abnormalities of bronchial airways on CT were associated with peribronchial cuffs of soft tissue or surrounding lymph nodes. In 17 patients, active tuberculous infection was confirmed either bacteriologically (n=15) and/or histologically (n=8). Pathologic study of the lesion obtained by bronchoscopic biopsy or thoracotomy showed dense bronchial and/or peribronchial fibrosis with interspersed black pigments. CONCLUSIONS: These findings strongly suggest that bronchial stenosis or obliteration with anthracotic pigmentation in the mucosa was caused by a fibrotic response to active or old tuberculous infection. To prevent the spread of tuberculosis and avoid unnecessary invasive procedures, detailed examinations for the presence of active tuberculosis should be performed in patients with this unique bronchoscopic finding.

Adult↗
PubMed1998

Localized form of bronchioloalveolar carcinoma: FDG PET findings.

OBJECTIVE: The aim of our study was to describe 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) findings of a localized form of bronchioloalveolar carcinoma and to compare those findings with other cell types of lung cancer. SUBJECTS AND METHODS: FDG PET was performed in 48 patients with lung cancer. The patients had carcinomas of various cell types: bronchioloalveolar carcinoma (n = 9), squamous cell carcinoma (n = 11), adenocarcinoma (n = 22), and other cell types (n = 6). Using FDG PET, we compared peak standardized uptake values among the various cell types of lung cancer. CT and pathologic findings for patients with bronchioloalveolar carcinoma were also reviewed. RESULTS: Overall, 48 malignant tumors showed a mean peak standardized uptake value of 8.0 +/- 4.1. The mean peak standardized uptake value was 3.5 +/- 2.2 for bronchioloalveolar carcinoma, 10.8 +/- 4.4 for squamous cell carcinoma, and 8.8 +/- 3.2 for adenocarcinoma. The mean peak standardized uptake value for bronchioloalveolar carcinoma was significantly lower than that for adenocarcinoma and squamous cell carcinoma (p < .001). On high-resolution CT scans, bronchioloalveolar carcinomas appeared as areas of ground-glass opacity (n = 4), as nodules (n = 2), as masses (n = 2), and as a ground-glass opacity plus consolidation (n = 1). On pathologic examination, bronchioloalveolar carcinomas were well differentiated, having moderate degrees of nuclear atypism, mild degrees of mitotic figure, desmoplasia, and necrosis. CONCLUSION: The localized form of bronchioloalveolar carcinoma shows significantly lower peak standardized uptake values than do other lung carcinomas. Thus, bronchioloalveolar carcinoma can be a potential cause of false-negative findings of malignancy on FDG PET scans. When bronchioloalveolar carcinoma is suggested, FDG PET results should be interpreted in combination with high-resolution CT findings.

Adenocarcinoma↗
PubMed1998

Nonspecific interstitial pneumonia with fibrosis: high-resolution CT and pathologic findings.

OBJECTIVE: The purpose of our study was to describe high-resolution CT findings of nonspecific interstitial pneumonia with fibrosis and to compare findings seen on CT with pathologic findings. MATERIALS AND METHODS: High-resolution CT findings of biopsy-proven non-specific interstitial pneumonia with fibrosis from 23 consecutive patients (one man and 22 women) were analyzed retrospectively by two chest radiologists. CT findings were compared with pathologic findings. RESULTS: The predominant high-resolution CT finding, seen in all patients, was bilateral patchy areas of ground-glass opacity with (35%) or without (65%) areas of consolidation. Irregular linear opacities (87%), thickening of bronchovascular bundles (65%), and bronchial dilatation (52%) were also frequently seen. Honeycombing was not seen in any patient. All parenchymal abnormalities showed subpleural predominance. Areas of ground-glass opacity with or without irregular linear opacity or bronchial dilatation on CT corresponded pathologically to areas of interstitial thickening caused by varying degrees of interstitial inflammation and fibrosis showing temporal uniformity. Areas of consolidation, seen at five biopsy sites, represented the areas of bronchiolitis obliterans organizing pneumonia, foamy cell collections in alveolar spaces, or microscopic honeycombing with mucin stasis. CONCLUSION: On high-resolution CT, nonspecific interstitial pneumonia with fibrosis is most commonly revealed as patchy subpleural areas of ground-glass opacity mixed with irregular linear opacity or bronchial dilatation. These areas represent interstitial thickening caused by varying degrees of interstitial inflammation, fibrosis, or both.

Adult↗
PubMed1998

Influence of environmental conditions on the kinetics and mechanism of dehydration of carbamazepine dihydrate.

The object of this project was to study the influence of temperature and water vapor pressure on the kinetics and mechanism of dehydration of carbamazepine dihydrate and to establish the relationship between the dehydration mechanism and the solid-state of the anhydrous phase formed. Three experimental techniques were utilized to study the kinetics of dehydration of carbamazepine dihydrate (C15H12N2O.2H2O)-thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and variable temperature powder X-ray diffractometry (VTXRD). These techniques respectively provide information about the changes in weight, heat flow and solid-state (phase) during the dehydration process. The instrumental setup was modified so that simultaneous control of both the temperature and the water vapor pressure was possible. The experiments were carried out at different temperatures, ranging from 26 to 64 degrees C. In the absence of water vapor, the dehydration followed the 2-dimensional phase boundary controlled model at all the temperatures studied. In the next stage, the water vapor pressure was altered while the studies were carried out at a single temperature of 44 degrees C. The dehydration was 2-dimensional phase boundary controlled at water vapor pressures < or = 5.1 torr while the Avrami-Erofeev kinetics (3-dimensional nucleation) was followed at water vapor pressures > or = 12.0 torr. In the former case, the anhydrous phase formed was X-ray amorphous while it was the crystalline anhydrous gamma-carbamazepine in the latter. Thus a relationship between the mechanism of dehydration and the solid-state of the product phase was evident. The dehydration conditions influence not only the mechanism but also the solid-state of the anhydrous phase formed. While the techniques of TGA and DSC have found extensive use in studying dehydration reactions, VTXRD proved to be an excellent complement in characterizing the solid-states of the reactant and product phases.

Anticonvulsants↗
PubMed1998

Age-related changes in blood pressure in the senescence-accelerated mouse (SAM): aged SAMP1 mice manifest hypertensive vascular disease.

Age-related changes in systolic blood pressure were assessed, using the senescence-accelerated mouse (SAM) model for aging research with strains SAMR1, SAMP1, and SAMP8. Each of the strains manifested a characteristic change in blood pressure with age. The SAMR1 strain, with normal aging, did not have chronologic changes from 2 to 27 months of age. The SAMP1 strain, with accelerated senescence, had a significant increase in blood pressure with age, and some (8 of 39) mice manifested hypertensive vascular disease characterized by high blood pressure, cardiac hypertrophy, and arteriolar fibrinoid necrosis at 11 to 14 months of age. The gradual increase in blood pressure after 8 to 10 months was considered to be preceded by progressive renal changes, from glomerulonephritis to contraction of the kidney, suggesting that the high blood pressure in the SAMP1 strain was of renal origin. Blood pressure in the SAMP8 strain, with age-related deficits in learning and memory, gradually decreased after 5 to 7 months of age, and was suggested to be due to the astrogliotic changes in response to spongiform degeneration in the medulla oblongata at 11 to 14 and 15 to 18 months of age.

Aging↗
PubMed1998

[Uterine and placental vascular lesions in pregnancy induced hypertension and its relationship to pregnancy outcome].

OBJECTIVE: To study the vascular lesions of the uterus and placenta in severe pregnancy induced hypertension (SPIH) and its relationship to pregnancy outcomes. METHODS: 29 cases of SPIH and 29 cases of normal term pregnancies (NTP) were examined to observe the expressions of IgA, IgG, IgM and C3 in the vascular walls of placental villus and uterus placental bed by immunohistochemical technique. RESULTS: (1) In SPIH, the positive expression rates of the IgA, IgG, IgM and C3 in the vascular wall of placental villus (20.1%, 24.1%, 72.4%, and 65.5%) and uterus placental bed (20.0%, 20.0%, 70.0% and 60.0%) were significantly higher than those of NTP (all P < 0.05), while there were no expression in NTP. (2) The thickening of endangium angiostenosis, fibronoid necrosis and acute arterial atherosis were found at the sites of positive expressions in SPIH. (3) In SPIH complicated by intrauterine growth retardation (IUGR), the positive expressions of the immunocomplex and complement in the vessel walls (76.2%) were significantly higher than those of the SPIH without IUGR (50%, all P < 0.05). CONCLUSION: In SPIH, there are depositions of immunocomplex and complement on the vessel walls of placental villus and uteroplacenta. Immunological factor plays an important role in the development of PIH.

Adult↗
PubMed1998

An observation on the mimic ecology of the oncomelania hupensis in three-Gorge-reservoir areas.

According to the modulation of three-gorge-reservoir water level, the two observation spots were established at Gaoyang Town and Jianshe Village in Xingshan County of Hubei Province in order to observe the survival and reproduction of the oncomelania under different ecological conditions. Our one-year observation revealed that most settled oncomelania died between June and August in the year and only a few of them survived the winter. The oncomelania hupensis's survival rate in group I, II, III settled in Gaoyang Town was 10%, 1%, 0%, respectively, and the oncomelania Sichuan's 12.5%, 22.5%, 13.5%. The rates obtained from spots in Jianshe Village is 0%, 2%, 0% and 9.5%, 19%, 3%, respectively. The survival rate of oncomelania Sichuan was higher than that of the oncomelania hupensis in the two spots. After draining the feeding pools, the soil samples were harvested and used for egg-hatching. The numbers of eggs that hatched in group I, II in Gaoyang were 1 and 2, respectively. The young oncomelania were found in each spot pool after the drainage, suggesting that the local condition is favorable to the oncomelania and the mating season of each group oncomelania is from April to August with the most active mating time being from May to June.

Animals↗
PubMed1998

[Occurrence of hyperventilation syndrome in Chinese patients].

OBJECTIVE: To evidence the occurrence of hyperventilation syndrome in Chinese patients. METHOD: Case report and literature review. RESULT: Three cases with manifest hyperventilation syndrome were reported. The diagnosis was based on the presence of several suggestive complaints occurring in a context of stress, and the reproduction of the most important complaints by the hyperventilation provocation test. Organic diseases as a cause of the symptoms had been excluded. Breathing therapy reducing the tendency to hyperventilate by acquiring an abdominal breathing pattern, with slowing down of expiration, markedly reduced complaints in the three patients. CONCLUSION: Hyperventilation syndrome occurs also in Chinese patients.

Adult↗
PubMed1998

[Studies on flavonoids from Fenugreek (Trigonella foenumgraecum L.)].

OBJECTIVE: To study the flavonoids in fenugreek (Trigonella foenumgraecum) produced in China. METHOD: The flavonoids were isolated with silica gel, polyamide and Sephadex LH-20 chromatography, and their structures were identified by physical, chemical properties and spectral analysis. RESULT: Five flavonoid compounds were isolated from fenugreek seeds and identified as vitexin, tricin, naringenin, quercetin and tricin-7-O-beta-D-glucopyranoside. CONCLUSION: Three flavonoids, tricin, naringenin and tricin-7-O-beta-D-glucopyranoside, were isolated from fenugreek as well as from the plants of Trigonella for the first time.

Apigenin↗
PubMed1998

[Experimental studies on dynamic changes of circulating antigens of Schistosoma japonicum in infected rabbits].

AIM: To observe the dynamic changes and disappearance of three kinds of schistosome circulating antigens(CAgs) in infected rabbits before and after praziquantel treatment. METHODS: Dot-ELISA assays were developed by using 3 McAbs to determine the dynamic changes of the gut-associated antigen (GAA), membrane-associated antigen (MAA) and soluble egg antigen (SEA) respectively in sera of rabbits infected with S. japonicum. RESULTS: By the 4th week after infection 39% of the rabbits infected with S. japonicum were GAA positive and only 8.6% were MAA or SEA positive. All the infected rabbits becOme positive with GAA, MAA and SEA by the 8th week after infection. The titers of the GAA, MAA and SEA in sera of the infected rabbits reached their peaks by the 10th week after infection. Titers from rabbits of the untreated group rabbits remained high level until the 27th week after infection. SEA titers were found negative in 10% of the infected rabbits in the treatment group by the 6th week after treatment. The titers of GAA of, MAA' and SEA were found negative in 20%, 80% and 70% of the rabbits in the treatment group, respectively the 8th after treatment. GAA, MAA and SEA in sera except one of the treated rabbits were all negative by the 14th week after treatment. CONCLUSION: The determination of GAA is useful for the early diagnosis of schistosomiasis, while the determination of, MAA and SEA might be used for the efficacy evaluation.

Animals↗