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Biomedical subjects

H Shi

Publications and source records attributed to H Shi.

At least 109 records · Page 6Linked to original sources
PubMed1999

Identification and characterization of multiple subtypes of muscarinic acetylcholine receptors and their physiological functions in canine hearts.

M2 receptors have long been believed to be the only functional subtype of muscarinic acetylcholine receptor (mAChR) in the heart, although recent studies have provided evidence for the presence of other subtypes. We performed a detailed study to clarify this issue. In the presence of tetramethylammonium (1 microM to 10 mM), a novel K+ current with both delayed rectifying and inward rectifying properties (IKTMA) was activated in single canine atrial myocytes. 4-Aminopyridine (0.05-2 mM) also induced a K+ current (IK4AP) with characteristics similar to but distinct from those of IKTMA. Both IKTMA and IK4AP were abolished by 1 microM atropine. IK4AP, but not IKTMA, was minimized by treatment with pertussis toxin. IKTMA was markedly decreased by 4-diphenylacetoxy-N-methylpiperidine methiodide (a selective antagonist for M3 subtype) but was not altered by pirenzepine (for M1), methoctramine (for M2), and tropicamide (for M4). Tropicamide substantially reduced IK4AP, but the antagonists for other mAChR subtypes had no effects on IK4AP. By comparison, IKACh (ACh-induced K+ current) was significantly depressed by methoctramine but was unaltered by other antagonists. Results from displacement binding of [methyl-3H]N-scopolamine methyl chloride with pirenzepine, methoctramine, 4-diphenylacetoxy-N-methylpiperidine methiodide, or tropicamide revealed the coexistence of multiple mAChR subtypes in canine atrium. Cloning of cDNA fragments and detection of mRNAs coding for M2, M3, and M4 provided further supporting evidence. Our results suggest that 1) multiple subtypes of mAChRs (M2/M3/M4) coexist in the dog heart and 2) different subtypes of mAChRs are coupled to different K+ channels. Our findings represent the first functional evidence for the physiological role of cardiac M3 and M4 receptors.

4-Aminopyridine↗
PubMed1999

Morphometric and histological study of coronary plaques in stable angina and acute myocardial infarctions.

OBJECTIVE: To compare the morphological difference of coronary plaques in acute myocardial infarction and stable angina to clarify the occurrence basis of these two different myocardial events. METHODS: Sixty-eight acute myocardial infarction cases and 34 stable angina postmortem cases were studied. The coronary arteries were dissected en block, fixed, decalcified, sectioned at a 3 mm interval and processed routinely for histologic examination. A computor-aided planimeter was used to measure plaque and lipid core area. RESULTS: Among the total 4089 coronary blocks in acute myocardial infarction, 2087 (51.0%) had a lipid core over 40% of the plaque area; while among the total 2030 blocks in stable angina, only 209 (10.3%) had a lipid core over 40% of the plaque area (P < 0.05). Sixty-one of the 68 (89.7%) acute myocardial infarction cases had thrombi among which 56 occurred on ruptured plaques; while no thrombus was found in stable angina. In addition, atheroemboli were found in most of the thrombus-negative acute myocardial infarction cases (6/7) but none in SA cases. CONCLUSIONS: Acute myocardial infarction and stable angina had different morphologic basis of the coronary plaques. The former had more plaques with a large lipid core than the latter. Acute myocardial infarction was caused mainly by plaque rupture and associated thrombus. But atheroembolus could be another very important cause of acute myocardial infarction.

Aged↗
PubMed1999

[Detection and significance of interleukin-16 in sputa from patients with bronchial asthma].

OBJECTIVE: To explore the significance of in the terleukin-16 (IL-16) in pathogenesis of bronchial asthma. METHODS: Induced sputum samples were obtained from 12 allergic asthmatics, 8 non-allergic asthmatics, 10 non-asthma allergic and 10 non-asthma non-allergic normal subjects. ELISA was used to determine the concentrations of IL-16 in sputum, and CD4+ T cells and activated eosinophils (EG2 cells) in sputum were detected by immunostaining. RESULTS: IL-16 levels in both allergic and non-allergic asthmatics were much higher than those in non-asthma allergic or non-asthma non-allergic normal subjects. Effective anti-asthma treatment led to a significant decrease in IL-16 levels in patients with acute asthma. It was also found that the percentages of CD4+ and EG2 cells were all positively correlated to IL-16 levels. CONCLUSIONS: IL-16 is involved in the asthmatic process by recruiting CD4+ T cells and thus plays an important role in CD4+ cell-dependent eosinophilic inflammation in asthmatic airways.

Adult↗
PubMed1999

[Effects of laminin on the invasive and metastatic behaviors of human salivary adenoid cystic carcinoma cell lines].

OBJECTIVE: To study the effect of laminin (LN) on invasive and metastastic behaviors of salivary adenoid cystic carcinoma (Acc) cell lines. METHODS: Immunohistochemistry, Boyden chamber in vitro motility, and adhesion test were used. LN and LNR (LN receptor) distributions in Acc-2 and Acc-M cells were studied with immunohistochemical staining. RESULTS: There were less LN and LNR found in Acc-2, but much more LN and LNR were present in the highly metastatic clone Acc-M. With the presence of exgenous LN, Acc-2 became activated showing a higher migration rate. The cell adhesion test showed that Acc-2 had stronger ability of adhesion than Acc-M with the presence of LN. CONCLUSION: The result suggests LN and LNR may play a vitral role in the invasion and metastasis of Acc.

Animals↗
PubMed1999

[A study on the roles of CD86 in antigen-induced eosinophil infiltration into airways and airway hyperresponsiveness].

OBJECTIVE: To explore the effect of CD86 on antigen-induced eosinophil infiltration into the airways and airway hyperresponsiveness in sensitized mice, and further elucidate the role of CD86 in the pathogenesis of bronchial asthma. METHODS: Female BALB/c mice (n = 8 for each group) were sensitized and challenged with ovalbumin to induce airway eosinophilia and airway hyperresponsiveness. Airway responsiveness was espressed by the provocative concentration of acetylcholine causing 50% increase in respiratory resistance (PC50). Effect of anti-CD86 monoclonal antibody (mAb) on antigen-induced changes of eosinophil numbers in brochoalveolar lavage fluid (BALF) and airway reactivity was observed. CD86 expression on BALF cells was detected by flow cytometry and concentrations of interleukin-4 and interleukin-5 in homogenized supernatant of lung tissue were determined by ELISA. RESULTS: In sensitized mice challenged with ovalbumin 20 minutes once a day for 6 days, the number of BALF eosinophils was (9.2 +/- 1.5) x 10(8)/L. However, no eosinophil could be found in the BALF from mice without ovalbumin sensitization and challenge. Also, ovalbumin treatment led to PC50 value decrease from (0.66 +/- 0.13) g/L to (0.17 +/- 0.07) g/L (P < 0.01). CD86 expression on BALF cells from ovalbumin sensitized- and challenged-mice (36.4 +/- 6.2) was much higher than that from control mice (12.3 +/- 3.6, P < 0.01). In mice treated with intravenous injection of anti-CD86 mAb before each challenge, BALF eosinophils decreased by 67% (P < 0.01), and PC50 value increased by 69% (P < 0.01). Our results showed that anti-CD86 mAb prevented antigen-induced airway eosinophilia and airway hyperresponsiveness accompanied by a decrement of levels of both interleukin-4 and interleukin-5 in lung tissue. CONCLUSIONS: Anti-CD86 mAb is able to inhibit antigen-induced airway eosinophilia and to ameliorate airway hyperresponsiveness, possibly by inhibiting production of interleukin-4 and interleukin-5. These data suggested that the blockade of airway antigen-presenting cells' functions couid be of value in treatment of human asthma.

Acetylcholine↗
PubMed1999

[Thyroid squamous-cell carcinoma showing thymus-like element (CASTLE): a report of eight cases].

OBJECTIVE: To report 8 cases of squamous-cell carcinoma showing thymus-like element (CASTLE) of the thyroid. METHODS: Clinical data and pathological sections were retrospectively reviewed. RESULTS: CASTLE of the thyroid differed from ordinary squamous-cell carcinoma (SCC) in that it not only presented typical squamous pattern of differentiation, but also admixed with thymic architecture, such as Hassall's corpuscles, lymphoepithelial-like structure and mature lymphocyte infiltration in the stroma. CASTLE of the thyroid and much better prognosis than that of the ordinary SCC of the thyroid with a median survival time of 10.5 year. Histogenesis of CASTLE was discussed. CONCLUSION: Thyroid CASTLE is of rare occurrence. It should be distinguished from SCC of thyroid in order to treat such patients adequately.

Adult↗
PubMed1999

[Comparative study of conventional CT and spiral CT in diagnosis of lung cancer].

OBJECTIVE: To observe and compare the findings of lung cancer with conventional CT and spiral CT. METHODS: One hundred and thirty-four cases of pathologicalty confirmed lung cancer, including 56 centrally located and 78 peripherally located lung cancer, were examined by conventional CT and spiral CT, and their findings compared. RESULTS: In 30 of the 56 cases with central lung cancer, the lesion was located in the right bronchus and in 26 of them the lesion was in the left bronchus. On spiral CT, the display rate of obstructive findings and invasion to big vessels in the mediastinum was higher than that on conventional CT. There was no remarkable difference in density of the lesion and detection of metastasis in hilar and mediastinal lymph nodes between conventional and spiral CT. In 34 of the 78 cases with peripheral lung cancer, the lesion was in the right lung and in 44 was the lesion in the left lung. Calcification, air-bronchogram, cavity and pleural indentation of the lesion in the peripheral lung cancer were better displayed by spiral than by conventional CT. CONCLUSION: Spiral CT is superior to conventional CT in the observation of signs characteristic of central and peripheral lung cancers.

Adult↗
PubMed1999

[CT findings of non-Hodgkin lymphoma in the head and neck].

OBJECTIVE: To evaluate the characteristic CT findings of non-Hodgkin lymphoma (NHL) in head and neck. METHODS: Thirty-six patients with the head and neck NHL consisted of 23 males and 13 females, median 49.2 years. All cases were categorized into two groups: extranodal and nodal NHL lesions. RESULTS: The extranodal NHL disease included 39 lesions (31 cases), and, the frequent head and neck sites of such lesions were Waldeyer's ring (n = 11), maxilla (n = 8), maxillofacial spaces (n = 7), salivery gland (n = 6), and others (n = 7). 30 lesions were soft tissue mass; 9 were mucosal thickening abnormality (including Waldeyer's ring in 6 lesions, maxilla in 2 lesions, and nasal cavity in one lesion). The majority of such extranodal NHL diseases were demonstrated on CT as non-necrosis (33 lesions) and uneven margin (26 lesions). Sixteen lymph node NHL lesions were composed of 6 NHL confined to neck lymph nodes and 10 combinations of nodal and extranodal NHL diseases. 5/6 of the former had the condition with rim enhancement, necrosis and confluent nodal mass. Of ten of the latter, 7 had the necrostic lesion with rim enhancement, and 3 had the lesion with confluent nodal mass. CONCLUSION: Multiple maxillofacial extranodal sites of soft tissue mass with the presence of non-necrosis and uneven margin should be considered as the characteristic sign of NHL disease in the head and neck. Most nodal NHL may have the lesion with necrosis and rim enhancement, and the confluent mass is commonly seen in NHL confined to the neck lymph nodes.

Adolescent↗
PubMed1999

[CT evaluation of the primary extracranial neoplastic diseases eroding the central skull base].

OBJECTIVE: To evaluate the central skull base erosion caused by primary extracranial mass lesions with CT. METHODS: Forty-nine patients (33 males and 16 females; mean, 40.2 years) suffered from the primary extracranial neoplastic diseases with middle skull base involvement were divided into two groups: group I (10 cases), primary osseous lesions of the central skull base and group II (39 cases), primary maxillofacial neoplasms. All lesions were confirmed histopathologically by surgery and biopsy. RESULTS: Four invasion patterns of the central skull base were identified on CT: I. resorption of the cortical bone (30 cases), including outer cortical margin destruction in 16 cases (group II lesions) and both inner and outer laminae resorption in 14 cases (4 group I lesions and 10 groups II lesions). II. ossification and thickening of the skull base (4 group I cases, all were fibrous dysplasia) III. erosive enlargement of the ovale and rotundam foramina (9 group II cases). IV. combined sclerosis and resorption of the skull base (6 cases, 2 group I lesions and 4 group II lesions). Involvement of the intracranial structures embraced the cavernous sinus (n = 12; group II lesions), temporal lobe (n = 11; 5 group I lesions and 6 group II lesions), and pituitary (n = 2, group II lesions). CT demonstrated the following central skull base structures were eroded: greater wing of sphenoid bone (n = 34), sphenoid body (n = 22), sphenoid process (n = 23), petrous bone (n = 15), and articular fossa of the temporal bone (n = 8). CONCLUSION: Osseous lesions originating from the central skull base have various CT manifestations. The cortical resorption of the central skull base may be regarded as a main pattern of bone erosion caused by primary maxillofacial neoplasms, and most of them have lesions involve the greater wing of sphenoid bone through the deeper maxillofacial spaces, such as the infratemporal, pterygopalatine and parapharyngeal spaces.

Adolescent↗
PubMed1999

[Morphometric study of inflammatory cells and smooth muscle cells in coronary plaques and their relation with plaque stability].

OBJECTIVE: To compare the content of inflammatory cells and smooth muscle cells in stable and unstable coronary plaques in order to clarify the role of these cells in the vulnerability of plaques. METHODS: Hearts from 12 postmortem acute myocardial infarction cases were studied. The epicardial coronary arteries were dissected en bloc, fixed, decalcified, cut at 4 mm intervals and routinely processed for HE sections. 163 stable plaques (with no or only little lipid core) and 163 unstable plaques (with lipid core size > 40% of plaque area) were studied immunohistochemically using monoclonal antibodies specific for macrophages (CD68), T lymphocytes (UCHL-1) and smooth muscle cells (actin). Computor aided planimetry was used to measure the positive area of different cells. RESULTS: The content of macrophage and T lymphocytes in unstable plaques were significantly higher than that in stable plaques (P < 0.05). CONCLUSIONS: Stable plaques and unstable plaques not only had different lipid core size but also had different inflammatory cell and smooth muscle cell content. The larger the lipid core and the more macrophages and T lymphocytes in the fibrous cap, the more unstable the plaque. The lipid core and inflammatory cells (including macrophages and T lymphocytes) are the two major determinants of the vulnerability of coronary plaques.

Actins↗
PubMed1999

[Separation and identification of thellungianin G from the root of Pimpinella thellungiana Wolff].

OBJECTIVE: To study the effective components in the root of Pimpinella thellungiana METHOD: Column chromatography with silica gel and ODS was employed for the isolation and purification of ingredients. Their structures were elucidated by spectral analysis. RESULT: Three compounds were obtained and identified as 2-(1',2'-epoxy)-4-methoxy pheryl-2-methyl-butyrate(I),4-(1'-propenyl) phenol(II) and 2-methyl butyric acid(III). CONCLUSION: Compound I is a new compound and named thellungianin G. Compounds II and III were separated from P. Thellungiana for the first time.

Phenylbutyrates↗
PubMed1999

[Epidemiological survey on orchard pollinosis].

OBJECTIVE: To investigate the prevalence of Orchard Pollinosis in China. METHOD: From 1995 to 1998, an epidemiological survey on orchard pollinosis was carried on among 1,660 primary and middle school students and 2,167 university students, including questionnaire investigation, nasal inspection and scratch test. From April to June of 1998, a clinical investigation of orchard pollinosis was adopted among 30 patients of allergic rhinitis including scratch test and nasal mucosa test. RESULT: 1. The total positive rate of orchard pollen scratch test was 6.7%, and the prevalence of orchard pollinosis was 0.37%. 2. 5 cases (16.7%) were hypersensitive to orchard pollen clinically in allergen test. CONCLUSION: Orchard pollinosis is one kind of important pollinosis and should be paid high attention to.

Adolescent↗
PubMed1999

[A clinical study on sudden deafness in juveniles].

OBJECTIVE: To understand the clinical characteristics, treatment efficacy and the main factors affecting the prognosis of sudden deafness in juveniles. METHOD: Clinical data of thirty-four cases about juvenile with sudden deafness were respectively analysesed. RESULT: 1) The number of male cases is as about four times as that of female cases, nearly one-third of the cases had a history of virus infection. 2) The total effective rate was 52.4%. The significantly differences among the different modalities were not found. 3) An association was found between the prognosis and the sex, the type of primary audiogram, the course of disease and the degree of hearing loss. The threshold of hearing at 4,000 Hz. was found valuable to judge the prognosis of sudden deafness in juveniles. The influence of the vertigo and tinnitus was not remarkable. CONCLUSION: Some aspects of sudden deafness in juvenile were similar to that in adult, however, there are also some special characteristics about it.

Adolescent↗
PubMed1999

[Hybridization experiments using Anopheles minimus from Hainan and Yunnan].

AIM: To observe whether there were any intra-species differences between Anopheles minimus from Hainan(H) and Yunnan(Y). METHODS: Anopheles minimus were collected from cattle shed on the spot. Each isofemale line was set up in the laboratory. Hybridization experiments were conducted by using forced mating between Anopheles minimus from Hainan and Yunnan, for observing the reproductive ability of F1 hybrids. Ovarian nurse cell polytene chromosomes of F1 hybrid females were examined, to observe any synapsis in different zones of chromosomes. RESULTS: No embryo formation was found within the eggs produced by group Y female x H male, the hatching rate was zero. Low hatching rate was shown in other groups with (H female x Y male) F1, except for groups with (H x Y) F1 x Y. Ovarian nurse cell polytene chromosomes from (H x Y) F1 hybrid females showed constant asynapsis at the 29th, 36th and 37th zones in the chromosome 3R, and at the 4th and 6th zones in the chromosome X. CONCLUSION: Reproductive isolation did appear in An. minimus from Hainan and Yunnan.

Animals↗
PubMed1999

[Expression of CD44v and nm23-H1 proteins in laryngeal carcinoma and its correlation with clinical significance].

OBJECTIVE: To investigate the correlation between the expression of two gene proteins and their clinical significance in laryngeal carcinoma. METHODS: Sixty fresh laryngeal carcinoma samples were analyzed and 20 para-carcinoma tissue and 12 normal laryngeal mucosa samples were studied as controls. All specimens were collected from patients operated on from 1996 to 1998 in the same department (including 52 males and 8 females, age ranged from 41 to 77). The quantitative expression of CD44v and nm23-H1 proteins was analyzed by flow cytometry (FCM) and immunofluorescence technique. RESULTS: 1. Higher level expression of CD44v and nm23-H1 proteins was detected in the laryngeal carcinoma specimen than in normal laryngeal mucosa. 2. The expression of CD44v protein was positively correlated with the metastasis, clinical staging and pathological classification; but not correlated with sex, age, tumor size, course of the disease, T classification and category of laryngeal cancer. 3. The expression of nm23-H1 protein was inversely correlated with metastasis and clinical staging while positively correlated with age and tumor size; no significant relations were found between the expression and the sex and course of the disease, T classification and category of laryngeal cancer. 4. There was an inverse correlation between the protein expression of CD44v and nm23-H1. CONCLUSION: CD44v and nm23-H1 probably play an important regulating role in the metastasis of laryngeal carcinoma.

Adult↗
PubMed1998

In vitro selection of RNA molecules that displace cocaine from the membrane-bound nicotinic acetylcholine receptor.

The nicotinic acetylcholine receptor (AChR) controls signal transmission between cells in the nervous system. Abused drugs such as cocaine inhibit this receptor. Transient kinetic investigations indicate that inhibitors decrease the channel-opening equilibrium constant [Hess, G. P. & Grewer, C. (1998) Methods Enzymol. 291, 443-473]. Can compounds be found that compete with inhibitors for their binding site but do not change the channel-opening equilibrium? The systematic evolution of RNA ligands by exponential enrichment methodology and the AChR in Torpedo californica electroplax membranes were used to find RNAs that can displace inhibitors from the receptor. The selection of RNA ligands was carried out in two consecutive steps: (i) a gel-shift selection of high-affinity ligands bound to the AChR in the electroplax membrane, and (ii) subsequent use of nitrocellulose filters to which both the membrane-bound receptor and RNAs bind strongly, but from which the desired RNA can be displaced from the receptor by a high-affinity AChR inhibitor, phencyclidine. After nine selection rounds, two classes of RNA molecules that bind to the AChR with nanomolar affinities were isolated and sequenced. Both classes of RNA molecules are displaced by phencyclidine and cocaine from their binding site on the AChR. Class I molecules are potent inhibitors of AChR activity in BC3H1 muscle cells, as determined by using the whole-cell current-recording technique. Class II molecules, although competing with AChR inhibitors, do not affect receptor activity in this assay; such compounds or derivatives may be useful for alleviating the toxicity experienced by millions of addicts.

Animals↗
PubMed1998

[A molecular variant of angiotensinogen gene is associated with myocardial infarction in Chinese].

OBJECTIVE: A molecular variant of the angiotensinogen(AGT) gene with threonine instead of methionine at position 235(i.e.,with M235T polymor- phism) has been shown to be associated with essential hypertension, preeclampsia, coronary atherosclerosis, coronary heart disease(CHD), myocardial infarction(MI) in Caucasians and in Japanese. The purpose of the present study was to assess whether the M235T polymorphism was associated with MI in a Chinese population. METHODS: M235T polymorphism in exon 2 of AGT gene was determined by polymerase chain reaction(PCR) and restriction endonuclease analysis in a study of 57 patients with MI and 76 non-CHD individuals as control. RESULTS: The frequencies of T235 allele(0.82) and 235TT genotype (0.70) in the MI group were higher than those in the control subjects(0.63 and 0.42 respectively, P=0.013 and P<0.025). AGT gene 235TT genotype was at significantly increased risk of MI(odds ratio 3.65, P=0.016) in analysis adjusted for several main CHD risk factors. CONCLUSION: There is a significant association between AGT gene 235TT genotype and MI, this genotype might be an independent risk for MI in Chinese population.

Aged↗