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Biomedical subjects

X Cai

Publications and source records attributed to X Cai.

At least 127 records · Page 7Linked to original sources
PubMed1998

Leptin, the hypothalamus and the regulation of adiposity.

The hypothalamus contains a wealth of peptide and non-peptide neurotransmitters, many of which have been shown experimentally to influence feeding behaviour and energy metabolism. Regulatory activities as complex as these are likely to be controlled by numerous neurotransmitters interacting at a variety of levels. The hierarchy of command of these neuronal circuits is not known, but it is possible that some converge on to a final common pathway, governed by the actions of a single neurotransmitter, through which all other influences ultimately operate. This review will discuss several of the more recently identified neurotransmitters and consider their validity as candidates in the regulation of energy homeostasis.

Adipose Tissue↗
PubMed1998

Calreticulin: an intracellular Ca++-binding protein abundantly expressed and regulated by androgen in prostatic epithelial cells.

Calreticulin was identified in a screen for androgen-response genes in the rat ventral prostate. Northern blot and Western blot analyses in the rat model showed that both calreticulin messenger RNA and protein are down-regulated by castration and up-regulated by androgen replacement in the prostate. Northern blot analysis showed that calreticulin expression level in the prostate is much higher than that in seminal vesicles, heart, brain, muscle, kidney, and liver. The regulation of calreticulin expression by androgen is only observed in the prostate and seminal vesicles, two male secondary sex organs. The induction of calreticulin by androgen in prostate organ culture partially resists protein synthesis inhibition, suggesting that calreticulin is a direct androgen-response gene. In situ hybridization and immunohistochemistry studies showed that calreticulin is an intracellular protein in prostatic epithelial cells. Because calreticulin is a major intracellular Ca++-binding protein with 1 high-affinity and 25 low-affinity Ca binding sites, our observations suggest that calreticulin is a promising candidate that mediates androgen regulation of intracellular Ca++ levels and/or signals in prostatic epithelial cells. The expression of calreticulin is also regulated by androgen in the mouse and human prostate, suggesting that androgen regulation and function of calreticulin in the prostate are conserved evolutionarily.

Androgens↗
PubMed1998

[Detection of telomerase activity in bronchoscopic brush-off cells in lung cancer patients].

OBJECTIVE: To investigate the diagnostic significance of the detection of telomerase activity in the exfoliated cells obtained from fiberobronchoscopic brushing. METHODS: The techniques of TRAP-PCR-ELISA and TRAP-silver staining were employed to detecte telomerase activity in 57 cases with pulmonary diseases. RESULTS: Telomerase activity in the lesion side of lung cancer patients (N = 23) was significantly higher than that in the contralateral side of the same patient (P < 0.05), and in patients with pneumonia (P < 0.05). Positive rate of telomerase activity detection in lung cancer patients (91.3%) was significantely higher than that of cytological examination (52.3%, P < 0.05). In 83.3% of the cases examined, exfoliated cells showing cytological dysplasia were found to be telomerase activity positive. CONCLUSION: Detection of telomerase activity in the exfoliated cells obtained from fiberobronchoscopic brushing may be an effective and sensitive method in the diagnosis of pulmonary malignant diseases.

Adenocarcinoma↗
PubMed1998

[Neurilemmoma of the larynx with three case reports].

Neurilemmoma of the larynx is rare. We report three cases who were treated in our hospital in recent decade. The tumours mainly involves the aryepiglottic folds, the ventricular folds or extending to the pyriform fossa, uncommon being subglottic. It is believed that the most likely nerve of origin is the superior laryngeal nerve. Surgical approach was median laryngotomy for 2 cases and lateral pharyngotomy for 1 case.

Adolescent↗
PubMed1998

[Leiomyosarcoma of larynx and hypopharynx].

The laryngeal and hypopharyngeal smooth muscle tumors are very rare. One case of hypopharyngeal leiomyosarcoma and two cases of laryngeal smooth muscle tumors were reported: one angioleiomyoma, one leiomyosarcoma and one carcinoleiomyosarcoma. The patients usually present no characteristic symptoms in early stage and the clinical symptoms are similar to squamous cell carcinoma. It is difficult to make a correct diagnosis before operation. Treatment of first choice consists of primary radical resection including a large part of normal tissue. Early lymph node metastasis is rare. Precautary neck dissection is not indicated for subclinic cervical nodal disease. Radiotherapy may be taken as adjuvant or palliative measures.

Aged↗
PubMed1998

[In vitro study on arsenic trioxide-induced apoptosis of retinoic acid resistant acute promyelocytic leukemia cell line(MR-2)].

OBJECTIVE: To study the possible mechanisms of arsenic trioxide (As2O3) in the treatment of acute promyelocytic leukemia (APL). METHODS: Retinoic acid resistant APL cell line MR-2 was used as in vitro model. The effect of As2O3 on MR-2 cell line was observed by cell viability, cell growth, cell morphology, flow cytometry assay, NBT reduction test and immunofluorescence analysis. RESULTS: 1.0 mumol/L of As2O3 could induce apoptosis of MR-2 cells and it correlated with the degradation of PML-RAR alpha fusion protein. CONCLUSIONS: The therapeutic effect of As2O3 for APL possibly differs from that of ATRA, however, PML-RAR alpha fusion protein may be the target of both the therapy.

Antineoplastic Agents↗
PubMed1998

Mirror writing in the elderly.

OBJECTIVE: To determine if examination of mirror writing in the elderly could be used to assess the degradation of the brain function. METHODS: The occurrence of mirror writing in 146 subjects was examined. Among them, 104 were males and 42 females. All subjects were university graduates. Age ranged from 40 to 85 years with an average of 62.7 +/- 13.4. These subjects were divided into two groups, a non-elderly group consisting of 60 subjects (41.1%) and an elderly group 86 subjects (58.9%). All 146 subjects were examined with 10 items for determination of handedness, mini-mental state examination and the written language of Chinese Aphasia Examination Scale (Draft) including spontaneous writing, writing from dictation and copying. The above mentioned performances of written language were done by left and right hand. RESULTS: The results of examination revealed that in 146 subjects there were 7 subjects with mirror writing, which occurred only in the elderly group, accounting for 8.1%. In the elderly group, mirror writing was found in one subject of 70-79 years group and 6 subjects of age over 80 years. Mirror writing appeared in the elderly was of mild degree with an average percentage of 1.9 +/- 0.4. CONCLUSION: It is suggested that examination of mirror writing in the elderly may be used to assess the degradation of the brain function in senile subjects.

Adult↗
PubMed1998

[Parapharyngeal space neoplasms and surgical treatment].

This paper reports surgical treated 66 cases of parapharyngeal space neoplasms. They consist of primary 52 and secondary 14 cases, which were 59 benign and 7 malignant tumors. The surgical procedures which have been used are oral approach in 5 cases, the parotid approach in 5 cases, the cervical approach in 47 cases, the cervical approach with mandibular swing in 7 cases and the postaurical C incision approach in 2 cases. The procedures and indications of the cervical approach or (and) its combination with mandibular swing are outlined. It is considered that these two surgical procedures can provide very safe and efficacious approaches to the removal of the primary parapharyngeal space neoplasms encountered.

Adenoma, Pleomorphic↗
PubMed1998

[Nonepithelial malignant neoplasms of the larynx and hypopharynx].

OBJECTIVES: Nonepithelial Malignant Neoplasms of the larynx and hypopharynx are rare. Their clinical features, diagnosis and treatment were discussed. METHODS: From 1985 to 1996, 23 cases of nonepithelial malignant neoplasms of the larynx and 3 cases of hypopharynx were diagnosed. There were 21 males and 5 females. Age of the patients ranged from 16 to 65 years. Laryngeal tumours included 11 cases of sarcomas, 1 extramedullary plasmocytoma, 9 lymphomas and 2 malignant melanomas. Hypopharyngeal tumours included 1 leiomyosarcoma and 2 malignant melanomas. Extensive resection was the first treatment for 21 patients. Then, according to their histopathologic features, irradiation or/and chemotherapy were chosen. RESULTS: Follow-up period was from 6 months to 10 years. There were 12 patients survived for 4 to 10 years, including 6 cases of laryngeal sarcomas, 2 supraglottic lymphomas, 2 malignant melanomas of the larynx, 1 malignant melanoma and 1 leiomyosarcoma of the hypopharynx. CONCLUSIONS: Characteristics for these tumours were: 1. usually covered by intact mucosa; 2. laryngeal tumours rarely metastasize to the cervical lymph nodes; 3. difficulties in histopathological diagnosis, and immunohistochemistry is helpful to differentiation and determination.

Adolescent↗
PubMed1998

[Parapharyngeal space neoplasms].

OBJECTIVE: To study parapharyngeal space (PPS) neoplasms which are rarely seen clinically. METHODS: A retrospective review was made of 59 patients with PPS neoplasm operated on from 1986 to July, 1997 in our institution. RESULTS: Neurogenic tumors were the most common neoplasms, which constituted about 60 percent in the primary parapharyngeal space neoplasms. High-resolution computed tomography or magnetic resonance imaging was essential for diagnosis and presurgical planning. The transcervical approach was the preferred procedure for 75% benign parapharyngeal tumors. Middle mandibulotomy was used in 3 cases, including 2 small tumors confined to the superior aspect of the PPS and 1 carotid body tumor which extended to the skull base. Lateral skull base approach was utilized for 1 schwannoma originating in the jugular foramen with extension into the PPS. CONCLUSIONS: We believe that transoral approach can be used for small tumors and transparotid approach may be especially indicated for removal of deep lobe parotid tumors with extension to the PPS. Middle mandibulotomy is a safe and efficacious approach for the removal of special PPS neoplasms.

Adenoma, Pleomorphic↗
PubMed1998

Hemodynamics of ophthalmic artery and central retinal artery and correlation with other factors in patients with primary open angle glaucoma.

OBJECTIVE: To investigate the hemodynamics of ophthalmic artery (OA) and central retinal artery (CRA) in patients with primary open angle glaucoma(POAG) and analyse the correlation between hemodynamics of OA and CRA and other factors. METHODS: The hemodynamics of OA and CRA in normal persons (102 eyes) and glaucomatous patients (102 eyes) were measured by Colour Doppler Image (CDI). The linear correlation analysis was made between OA and CRA about each of the following parameters: the peak systolic flow velocity (Vmax), the end diastolic velocity (Vmin). The multiple stepwise regression analysis was taken to investigate the correlation between each of the following hemodynamics of OA and CRA: Vmax and Vmin in 74 eyes with POAG and each of the following related factors in hemorrheology: whole blood apparent viscosity at low, medium and high shear rate, plasma viscosity and hematocrit. The multiple linear regression was applied to investigate the correlation between each of the following hemodynamics of OA and CRA: Vmax and Vmin in 69 eyes with POAG and each of the following blood vessel filling time: the arm-retinal artery (A-AT) and retinal artery-venous (A-VT) of the fundus fluorescein angiography(FFA). RESULTS: The Vmax, Vmin and time-averaged maximum velocity (Vmean) of OA and CRA in patients with POAG were lower than those in normal persons, but the resistance index (RI) of OA and CRA was higher than those in normal. There was a positive correlation between OA and CRA in Vmin, but a negative correlation between Vmin of OA and plasma viscosity. The whole blood apparent viscosity at low shear rate was clodely related to Vmax and Vmin of CRA. Also there was a negative correlation between Vmax of CRA and A-AT of the FFA. CONCLUSION: There was abnormal hemodynamics, which is influenced by blood viscosity, of OA and CRA in patients with POAG. Abnormal hemodynamics can affect the blood supply to optic disc and retina in POAG.

Blood Flow Velocity↗
PubMed1997

Mismatch-sensitive hybridization detection by peptide nucleic acids immobilized on a quartz crystal microbalance.

A quartz crystal microbalance DNA hybridization biosensor, based on thiol-derivatized peptide nucleic acid (PNA) probes, offers unusual in situ differentiation of single-base mismatches. A large excess of a single-base mismatch oligonucleotide has no effect on the frequency response of the target. Such remarkable distinction between perfect matches and mismatches is illustrated by the detection of a common mutation in the p53 gene. The greater specificity of the new mass-sensitive indicatorless hybridization device over those of analogous PNA-based carbon electrodes is attributed to the formation of a PNA monolayer and the use of a hydrophilic ethylene glycol linker. The improved specificity is coupled to very fast (3-5 min) hybridization in a low-ionic-strength medium.

Biosensing Techniques↗
PubMed1997

Genes regulated by androgen in the rat ventral prostate.

Genes that are regulated by androgen in the prostate were studied in the rat. Four of the less than 10 genes that are down-regulated by androgen in the ventral prostate of a 7-day castrated rat were identified; their mRNAs decayed with identical kinetics. Twenty-five of the estimated 56 genes that are up-regulated by androgen in the castrated prostate have been isolated. The up-regulated genes fall into two kinetic types. Early genes are significantly up-regulated by 6.5 hr whereas the delayed genes respond mainly after 24 hr from the time of androgen replacement. These androgen-response genes are also regulated in the prostate by castration, indicating that these genes could play important roles in androgen-induced regrowth and/or castration-induced regression of the prostate during hormonal manipulation. A survey of the tissue specificity showed that the androgen-response gene expression program in the prostate is mainly prostate-specific. Total RNA Northern blot analysis detects the expression of about 16 up-regulated genes and 3 down-regulated genes in the prostate only. Four up-regulated genes and one down-regulated gene are regulated by androgen in both the prostate and seminal vesicles but not in other organs. The expression of the remaining androgen-response genes is not limited to the prostate but is only responsive to androgen in the prostate. This survey of the androgen-response gene expression program provides insights into the molecular and cellular mechanisms of androgen action in the prostate.

Androgens↗
PubMed1997

Comparison of fusion phage libraries displaying VH or single-chain Fv antibody fragments derived from the antibody repertoire of a vaccinated melanoma patient as a source of melanoma-specific targeting molecules.

A single-chain Fv (scFv) fusion phage library derived from random combinations of VH and VL (variable heavy and light chains) domains in the antibody repertoire of a vaccinated melanoma patient was previously used to isolate clones that bind specifically to melanoma cells. An unexpected finding was that one of the clones encoded a truncated scFv molecule with most of the VL domain deleted, indicating that a VH domain alone can exhibit tumor-specific binding. In this report a VH fusion phage library containing VH domains unassociated with VL domains was compared with a scFv fusion phage library as a source of melanoma-specific clones; both libraries contained the same VH domains from the vaccinated melanoma patient. The results demonstrate that the clones can be isolated from both libraries, and that both libraries should be used to optimize the chance of isolating clones binding to different epitopes. Although this strategy has been tested only for melanoma, it is also applicable to other cancers. Because of their small size, human origin and specificity for cell surface tumor antigens, the VH and scFv molecules have significant advantages as tumor-targeting molecules for diagnostic and therapeutic procedures and can also serve as probes for identifying the cognate tumor antigens.

Amino Acid Sequence↗