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Biomedical subjects

J Cai

Publications and source records attributed to J Cai.

At least 91 records · Page 5Linked to original sources
PubMed2000

Separation of cytochrome c-dependent caspase activation from thiol-disulfide redox change in cells lacking mitochondrial DNA.

Release of mitochondrial cytochrome c (cyt c) is an early and common event during apoptosis. Previous studies showed that the loss of cyt c triggered superoxide production by mitochondria and contributed to the oxidation of cellular thiol-disulfide redox state. In this study, we tested whether loss of the functional electron transport chain due to depleting mitochondrial DNA (mtDNA) would affect this redox-signaling mechanism during apoptosis. Results showed that cyt c release and caspase activation in response to staurosporine treatment were preserved in cells lacking mitochondrial DNA (rho0 cells). However, unlike the case with rho+ cells, in which a dramatic oxidation of intracellular glutathione (GSH) occurred after mitochondrial cyt c release, the thiol-disulfide redox state in apoptotic rho0 cells remained largely unchanged. Thus, mitochondrial signaling of caspase activation can be separated from the bioenergetic function, and mitochondrial respiratory chain is the principal source of ROS generation in staurosporine-induced apoptosis.

Adenylate Kinase↗
PubMed2000

Oxidative damage and protection of the RPE.

This review provides a model for the role of oxidative stress in the etiology of age-related macular degeneration (AMD). Epidemiological studies of diet, environmental and behavioral risk factors suggest that oxidative stress is a contributing factor of AMD. Pathological studies indicate that damage to the retinal pigment epithelium (RPE) is an early event in AMD. In vitro studies show that oxidant treated RPE cells undergo apoptosis, a possible mechanism by which RPE cells are lost during early phase of AMD. The main target of oxidative injury seems to be mitochondria, an organelle known to accumulate genomic damages in other postmitotic tissues during aging. The thiol antioxidant GSH and its amino acid precursors protect RPE cells from oxidant-induced apoptosis. Similar protection occurs with dietary enzyme inducers which increase GSH synthesis. These results indicate that therapeutic or nutritional intervention to enhance the GSH antioxidant capacity of RPE may provide an effective way to prevent or treat AMD.

Aging↗
PubMed2000

The (2 + 2) REMPI study of methylamine in the 430-485-nm region.

The mass resolved (2 + 2) resonance enhanced multiphoton ionization (REMPI) spectra of methylamine (MA) via the (nN,3s) Rydberg state were obtained in the 430-485-nm region using a time-of-flight (TOF) mass spectrometer. They have the same vibrational structure mainly due to NH2-wagging mode excitation. The parent ion relative intensity increases at longer wavelengths. The multiphoton ionization mechanism is discussed.

Lasers↗
PubMed2000

Hepatocyte transplantation in rats with decompensated cirrhosis.

Hepatocyte transplantation improves the survival of laboratory animals with experimentally induced acute liver failure and the physiological abnormalities associated with liver-based metabolic deficiencies. The role of hepatocyte transplantation in treating decompensated liver cirrhosis, however, has not been studied in depth. To address this issue, cirrhosis was induced using phenobarbital and carbon tetrachloride (CCL(4)) and animals were studied only when evidence of liver failure did not improve when CCL(4) was held for 4 weeks. Animals received intrasplenic transplantation of syngeneic rat hepatocytes (G1); intraperitoneal transplantation of syngeneic rat hepatocytes (G2); intraperitoneal transplantation of a cellular homogenate of syngeneic rat hepatocytes (G3); intraperitoneal transplantation of syngeneic rat bone marrow cells (G4); or intrasplenic injection of Dulbecco's modified Eagle medium (DMEM) (G5). After transplantation, body weight and serum albumin levels deteriorated over time in all control (G2-G5) animals but did not deteriorate in animals receiving intrasplenic hepatocyte transplantation (G1) (P <.01). Prothrombin time (PT), total bilirubin, serum ammonia, and hepatic encephalopathy score were also significantly improved toward normal in animals receiving intrasplenic hepatocyte transplantation (P <. 01). More importantly, survival was prolonged after a single infusion of hepatocytes and a second infusion prolonged survival from 15 to 128 days (P <.01). Thus, hepatocyte transplantation can improve liver function and prolong the survival of rats with irreversible, decompensated cirrhosis and may be useful in the treatment of cirrhosis in humans.

Animals↗
PubMed2000

Alterations in cathepsin H activity and protein patterns in human colorectal carcinomas.

Our analyses of cathepsin H activity levels and protein forms in human colorectal cancers compared to matched control mucosa support the concept that altered proteinase expression patterns may reflect both cancer stage and site. Cathepsin H-specific activity was significantly increased in colorectal cancers compared to control mucosa (P = 0.003; n = 77). Highest specific activities and cancer/normal ratios (C/N) for activity were measured in Dukes' B and C stage carcinomas, cancers involved in local spread and invasion to lymph nodes. In contrast, cathepsin B and L activities analysed in the same paired extracts had been shown to be most frequently elevated in earlier stage carcinomas (Dukes' A and B), confirming that cathepsin H demonstrates a distinct pattern of expression during colorectal cancer progression. Although cathepsin H activities were most commonly elevated in Dukes' C cancers at all colon sites, both specific activity and C/N ratios were significantly higher for cancers of the left colon compared to other colon locations. A subset of 43 paired extracts analysed on Western blots also revealed consistent changes in cathepsin H protein forms in cancers. Normal mucosa typically showed a strong protein doublet at 31 and 29 kDa while cancers demonstrated decreased expression or total loss of the 31 kDa protein (90% of cases), equal or increased expression of the 29-kDa protein (67% of cases) and the new appearance or up-regulation of a cathepsin H band at 22 kDa (78% of cases). C/N ratios for cathepsin H enzyme activity correlated significantly with C/N ratios for the 29 kDa mature single-chain protein form (P < 0.001), with increased activity most commonly associated with elevated expression of 29-kDa cathepsin H but also with up-regulation of the 22-kDa band, suggesting a shift to more fully processed, mature active cathepsin H protein forms in cancers. Changes in cathepsin H expression were also detected by immunohistochemistry as elevated cathepsin H staining in tumour epithelial cells.

Adult↗
PubMed2000

Micrometastasis in lymph nodes and microinvasion of the muscularis propria in primary lesions of submucosal gastric cancer.

BACKGROUND: It is important to clarify the clinicopathologic characteristics of micrometastasis in lymph nodes and microinvasion in primary lesions for the treatment options with regard to submucosal gastric cancer. METHODS: We examined 1945 lymph nodes and 68 primary tumors resected from 79 patients with submucosal gastric cancer. Two consecutive sections were prepared for simultaneous staining with ordinary hematoxylin and eosin and immunostaining with anticytokeratin antibody (CAM 5.2), respectively. RESULTS: The incidence of nodal involvement in 79 patients with submucosal gastric cancer increased from 13% (10/79 patients) by hematoxylin and eosin staining to 34% (27/79 patients) by cytokeratin immunostaining. Micrometastases in the lymph nodes were found in 17 of 69 patients (25%), with cancer-free nodes examined by hematoxylin and eosin. Microinvasion to the muscularis propria was found in 11 of 68 patients (16%) who were histologically diagnosed with submucosal gastric cancer. Survival analysis demonstrated a lesser 5-year survival in the patients with micrometastasis in lymph nodes (82%) and with microinvasion to muscularis propria (73%). A high incidence of nodal involvement was found in submucosal cancers of large size (> 2 cm; 43%), a depressed type (48%), lymphatic invasion (73%), and deeper submucosal invasion (submucosal 3, 53%). A higher incidence of microinvasion was found with the diffuse-type carcinoma (33%). CONCLUSIONS: Cytokeratin immunostaining is useful for detecting micrometastasis and microinvasion in submucosal gastric cancer. Tumor size, macroscopic type, lymphatic invasion, and the depth of submucosal invasion are strongly associated with lymph node involvement.

Adult↗
PubMed2000

Crystallization and preliminary crystallographic study of cucurmosin, a ribosome-inactivating protein from the sarcocarp of Cucurbita moschata.

Cucurmosin, a ribosome-inactivating protein purified from pumpkin, the sarcocarp of Cucurbita moschata, has been crystallized using polyethylene glycol as a precipitant. The crystals belong to space group P2(1)2(1)2(1) and have unit-cell parameters a = 41.91, b = 59. 48, c = 98.78 A. There is one molecule in the asymmetric unit. The diffraction data to 3.0 A resolution were collected on a MAR Research image-plate detector.

Crystallization↗
PubMed2000

Exposure to electromagnetic fields and suicide among electric utility workers: a nested case-control study.

OBJECTIVE: To examine mortality from suicide in relation to estimated exposure to extremely low-frequency electromagnetic fields in a cohort of 138,905 male electric utility workers. METHODS: Case-control sampling, which included 536 deaths from suicide and 5, 348 eligible controls. Exposure was classified based on work in the most common jobs with increased exposure to magnetic fields and indices of cumulative exposure to magnetic fields based on a measurement survey. RESULTS: Suicide mortality was increased relative to work in exposed jobs and with indices of exposure to magnetic fields. Increased odds ratios (ORs) were found for years of employment as an electrician (OR, 2.18; 95% confidence interval [CI], 1.25-3.80) or line worker (OR, 1.59; 95% CI, 1.18-2.14), whereas a decreased OR was found for power plant operators (OR, 0.67; 95% CI, 0.33-1.40). A dose-response gradient with exposure to magnetic fields was found for exposure in the previous year, with a mortality OR of 1.70 (95% CI, 1.00-2.90) in the highest exposure category. Stronger associations, with ORs in the range of 2.12 to 3.62, were found for men younger than 50 years. CONCLUSIONS: These data provide evidence for an association between occupational electromagnetic fields and suicide that warrants further evaluation. A plausible mechanism related to melatonin and depression provides a direction for additional laboratory research and epidemiologic evaluation.

Adult↗
PubMed2000

Exposure to electromagnetic fields and suicide among electric utility workers: a nested case-control study.

OBJECTIVES: This nested case-control study examines mortality from suicide in relation to estimated exposure to extremely low frequency electromagnetic fields (EMFs) in a cohort of 138,905 male electric utility workers. METHODS: Case-control sampling included 536 deaths from suicide and 5348 eligible controls. Exposure was classified based on work in the most common jobs with increased exposure to magnetic fields and indices of cumulative exposure to magnetic fields based on a measurement survey. RESULTS: Suicide mortality was increased relative to work in exposed jobs and with indices of exposure to magnetic fields. Increased odds ratios (ORs) were found for years of employment as an electrician (OR 2.18; 95% confidence interval (95% CI) 1.25 to 3.80) or lineman (OR 1.59; 95% CI 1.18 to 2.14), whereas a decreased OR was found for power plant operators (OR 0.67; 95% CI 0.33 to 1.40). A dose response gradient with exposure to magnetic fields was found for exposure in the previous year, with a mortality OR of 1.70 (95% CI 1.00 to 2.90) in the highest exposure category. Stronger associations, with ORs in the range of 2.12-3.62, were found for men <50 years of age. CONCLUSION: These data provide evidence for an association between occupational electromagnetic fields and suicide that warrants further evaluation. A plausible mechanism related to melatonin and depression provides a direction for additional laboratory research as well as epidemiological evaluation.

Adolescent↗
PubMed2000

Diet and apoptosis.

A range of compounds in or derived from the diet modulates apoptosis in cell cultures in vitro. These observations have important implications concerning the mechanisms whereby dietary components affect health. Proapoptotic compounds could protect against cancer by enhancing elimination of initiated, precancerous cells, and antiapoptotic compounds could promote tumor formation by inhibiting apoptosis in genetically damaged cells. Proapoptotic compounds could also contribute to age-related degenerative diseases by activating cell death in postmitotic cells or shifting the normal balance of mitosis and apoptosis in tissues with regenerative capacity. Many age-related diseases, for example macular degeneration and Parkinson's disease, appear to have oxidative stress as an underlying component that interacts with genetic, dietary, and environmental factors to determine relative risk in an individual. Oxidative stress activates apoptosis, and antioxidants protect against apoptosis in vitro; thus, a central role of dietary antioxidants may be to protect against apoptosis. However, little in vivo data are available to directly link diet with altered apoptosis as an underlying determinant of disease. Moreover, the possible antagonistic effects of different dietary components and the uncertainty about whether proapoptotic compounds that may protect against cancer could contribute to degenerative diseases and vice versa indicate that there is a great need for better in vivo assessment of apoptosis and that caution should be exercised when extrapolating in vitro data on apoptosis to in vivo dietary recommendations.

Age Factors↗
PubMed2000

In vivo evaluation of carborane gadolinium-DTPA complex as an MR imaging boron carrier.

The evaluation of the Gd-carborane complex 2 as an MR imaging and boron carrier agent was carried out in vivo using tumor-bearing Donryu rats, MRI, ICP-AES, and alpha-autoradiography. The MR imaging revealed that the carborane Gd-DTPA 2 was metabolized slower in the body than Gd-DTPA 1. The results of the ICP-AES method indicated that compound 2 was incorporated into normal tissues and metabolized quickly, whereas it was not accumulated into tumor or brain tissue. The alpha-autoradiography showed that a high level of boron was obtained in the internal organs and in the necrosis of tumor tissue.

Animals↗
PubMed2000

Negative symptoms in patients with major depressive disorder: a preliminary report.

OBJECTIVE: The purpose of this study was to examine negative symptoms (NSs) in patients with major depressive disorder (MDD) and their relation to depressive symptoms (DSs) and other psychiatric symptoms. BACKGROUND: Features similar to NSs were previously described in patients with depression. METHOD: The Hamilton Rating Scale for Depression (HRSD), Positive and Negative Symptom Scale (PANSS), Scale for the Assessment of Negative Symptoms (SANS), and Mini-Mental State Examination were administered to 23 patients with MDD and 10 normal control subjects. RESULTS: As expected, the mean scores of the HRSD, SANS, and negative symptom subscale of the PANSS of the patients with MDD were significantly higher than those of control subjects, validating the clinical significance of NSs as well as DSs in MDD patients. Within the MDD group, although measures of NSs were intercorrelated, there were no other correlations between the measures. Thus, measures of NSs and DSs were not intercorrelated. When the HRSD was divided in two subscales, HRSD negative symptom subscale scores but not HRSD depressive symptom subscale scores were correlated with PANSS negative symptom subscale and SANS total scores as well as with scores on the affective flattening subscale. CONCLUSIONS: These results suggest a high level of NSs in patients with MDD, which are distinct from positive symptoms of depression and may constitute a distinct dimension. Negative symptoms and DSs in MDD may represent separate constructs. Further, the HRSD might have possible subscales in MDD as it does in schizophrenia.

Adult↗
PubMed2000

Generic data modeling for home telemonitoring of chronically ill patients.

Management of many types of chronic diseases such as diabetes and asthma relies heavily on patients' self-monitoring of their disease conditions. In recent years, internet-based home telemonitoring systems that allow transmission of patient data to a central database and offer immediate access to the data by the care providers have become available. However, these systems often work with only one or a few types of medical devices and thus are limited in the types of diseases they can monitor. For example, a system designed to collect spirometry data from asthmatic patients cannot be easily adapted to collect blood glucose data from diabetic patients. This is because different medical devices produce different types of data and the existing telemonitoring systems are generally built around a proprietary data schema specific for the device used. In this paper, we describe a generic data schema for a telemonitoring system that is applicable to different types of medical devices and different diseases, and show an implementation of the schema in a relational database suitable for a variety of telemonitoring activities.

Asthma↗
PubMed2000

[Changes of hepatic energy metabolism following partial hepatopetal blood occlusion].

OBJECTIVE: To evaluate the changes of hepatic energy metabolism by temporary occlusion of partial hepatopetal blood. METHODS: The animal mode of partial hepatopetal blood occlusion (PBO) was established without portal stasis. The hepatic energy metabolism parameters including adenosine triphosphate, respiratory control ratio, P/O ratio, and arterial ketone bodies ratio were studied following 30 min ischemia or 1, 6, and 24 h of reperfusion. The total hepatopetal blood occlusion (TBO) and sham groups served as control. RESULTS: The parameters of hepatic motochondrial function reflecting hepatic damage to ischemia-reperfusion showed different in PBO comparing with TBO group. The functional lesion was restored progressively in PBO-30 min group, but it was maintained low level in TBO-30 min group. CONCLUSION: The results suggest that it is beneficial to restoration of the hepatic energy metabolism in the ischemia-reperfusion injury by partial hepatopetal blood occlusion.

Adenosine Triphosphate↗
PubMed2000

[The contribution of phacoemulsification to combined cataract and glaucoma surgery].

OBJECTIVE: To study the safety and effectiveness of phacoemulsification (phaco) in trabeculectomy combined with cataract extraction (phacotrabeculectomy) and posterior chamber intraocular lens (IOL) implantation. METHODS: 68 eyes with glaucoma and cataract were randomly divided into two groups: the phacotrabeculectomy with IOL implantation and modern extracapsular cataract extraction (ECCE), trabeculectomy and IOL implantation. RESULTS: Postoperatively, in the phaco group, the intraocular pressure (IOP) decreased obviously at the early stage (P < 0.05), the number of cases necessary for the use of anti-glaucoma drug was decreased, the mean kinds of the drug applied were markedly decreased (P < 0.05), the visual acuity improved quickly, significantly and steadily, and the complications were less than that in the ECCE group. CONCLUSIONS: The phaco's triple surgery is safe and effective. In cases with glaucoma and cataract, the surgery is indicated even when the cataract is not mature or premature.

Aged↗
PubMed2000

[Isolation and identification of HN-98 strain of spotted fever group rickettsiae].

OBJECTIVE: One strain of rickettsiae was isolated from a patient with unknown fever from Qiongzhong county in Hainan Province in 1998, using embryonated hen eggs and proved to be the member of rickettsiae by the methods of morphology. It was named HS-98 strain after the name of the place and the year it was isolated. METHODS: The isolate was identified by methods of Microcomplement fixation assay and OCR/RFLP and compared with known species and strains of SFGR by DNA polymerase chain reaction and DNA polymerase chainreaction and was followed by restriction endonuclease fragment length polymorphism analysis. RESULTS: Results demonstrated that HN-98 strain was antigenically and genotypically identical to R. sibirica 246. CONCLUSION: The results suggested that there existed natural foci of spotted fever in Qiongzhong Area of Hainan Province.

Adult↗