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Biomedical subjects

F Wang

Publications and source records attributed to F Wang.

783 records · Page 44Linked to original sources
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Inhibitory effect of deferoxamine mesylate and low iron diet on the 13762NF rat mammary adenocarcinoma.

The iron chelator deferoxamine mesylate has been shown to inhibit the growth of a variety of human malignant cell lines and the rat 13762NF mammary adenocarcinoma cell line. In vivo studies in mice have also demonstrated that an iron deficiency induced by either feeding a low iron diet or injecting the iron chelator deferoxamine mesylate decreases tumor growth. In this study Fisher rats were transplanted with the 13762NF mammary adenocarcinoma and divided into four groups: normal diet, normal diet plus deferoxamine mesylate treatment, low iron diet and low iron diet plus deferoxamine mesylate treatment. The measurements of tumor size and body weight were recorded weekly. We found that treatment with either deferoxamine mesylate or a low iron diet decreased rat tumor growth, but the greatest inhibitory effect on tumor growth occurred when the rats were treated with deferoxamine mesylate injections plus fed a low iron diet. These treatments did not significantly inhibit the weight gain of the rats. At the end of the experiments measurement of serum iron proved that these treatments caused iron deficiency, but there was no significant treatment related alteration in blood hematocrit. We therefore concluded that deferoxamine mesylate may be a useful chemotherapeutic agent in the treatment of breast cancer, when used in combination with standard chemotherapeutic regiments or with other agents that interfere with iron metabolism, and further that the restricting of iron intake should be considered when planning chemotherapy for all cancer patients.

Adenocarcinoma↗
PubMedDate not supplied

Patients' satisfaction and their perception of the pharmacist.

OBJECTIVE: To explore the relationships between patients' satisfaction and (1) the level of pharmaceutical care services received, (2) patients' perceptions of the personal attention paid to them by the pharmacist, and (3) patients' perceptions of the pharmacist's ability to help them manage their asthma and prevent asthma-related problems. DESIGN: Exploratory study using mail or telephone survey methods. PATIENTS OR OTHER PARTICIPANTS: Asthma patients (n = 250) enrolled in one of two Florida managed care organizations. MAIN OUTCOME MEASURES: Predictor variables were level of pharmaceutical care and patients' perceptions of personal attention and their pharmacist's ability to help them control their asthma. Outcome variable was patients' overall satisfaction with the care they received from their pharmacist. RESULTS: The direct causal effects of level of care (standardized regression coefficient, beta = 0.07) and patients' perception of pharmacists' ability to help (beta = 0.01) on satisfaction were nonsignificant. Only personal attention had a significant direct path coefficient to patient satisfaction (beta = 0.63). Although the level of care was associated with patient satisfaction (r = 0.32), its direct effect was not significant because of its joint association (r = 0.27) with personal attention. Patients' satisfaction was associated with the level of pharmaceutical care and their perception of the pharmacist's ability to help them with their asthma. However, personal attention from the pharmacist was most influential. CONCLUSION: Patients may be less able to judge the technical quality of the care they receive, but they do judge their social interaction with the pharmacist. Pharmacy professionals must increase patients' awareness of the value of pharmaceutical care services and make it important to their judgment of satisfaction.

Asthma↗
PubMedDate not supplied

Doxorubicin-gallium-transferrin conjugate overcomes multidrug resistance: evidence for drug accumulation in the nucleus of drug resistant MCF-7/ADR cells.

Development of multidrug resistance (MDR) in cancer cells decreases net doxorubicin (ADR) uptake as a result of increased efflux, increased intracellular sequestration, and decreased membrane permeability. In this study, we investigated whether conjugation of ADR to transferrin (Tf) could overcome MDR in breast cancer cells. The multidrug resistant MCF-7/ADR breast cancer cell line was over 1000-fold more resistant to ADR, than its parental MCF-7 cell line, as determined by 3[H]-thymidine assay. The MCF-7/ADR cell line also expressed both MDR1 and MRP genes, as detected by RT-PCR. The ADR was coupled using a glutaraldehyde technique to human transferrin saturated with either ferric chloride (Fe-Tf) or gallium nitrate (Ga-Tf). These conjugates were tested for cytotoxicity on both MCF-7 and MCF-7/ADR cells after 6 days of incubation. The doxorubicin-gallium-transferrin conjugate (ADR-Ga-Tf) exhibited approximately the same inhibitory effect as ADR on MCF-7 cells with IC50s of 2.34 x 10(-3) microM and 1.42 x 10(-3) microM, respectively. However in MCF-7/ADR cells ADR-Ga-Tf reversed resistance to free ADR and decreased 100-fold the IC50 from 8.98 microM with free ADR to 9.52 x 10(-2) microM. ADR-Fe-Tf was 10-fold more inhibitory to MCF-7/ADR cells than free ADR. Compared to Ga-Tf, ADR-Ga-Tf was 500- and 3000-fold more inhibitory to MCF-7 and MCF-7/ADR cells, respectively. These results demonstrated that ADR-Ga-Tf reverses resistance to free ADR and Ga-Tf in MCF-7/ADR cells. The distribution of ADR in both cell lines was examined by fluorescence microscopy. It was noted that ADR mainly accumulated in the cytoplasm around the nucleus in MCF-7/ADR cells, but in both the cytoplasm and nucleus of MCF-7 cells. However the conjugate of ADR-Ga-Tf allowed ADR to accumulate in the cytoplasm and nucleus of both the MCF-7/ADR and MCF-7 cells. Further investigation of MDR1 and MRP genes expression by RT-PCR demonstrated that Ga-Tf decreased expression of the MRP more than the MDR1 gene. Therefore the reversal of resistance to ADR by the ADR-Ga-Tf conjugate is mediated by the transferrin receptor transmembrane transport mechanism, redistribution of ADR into the nucleus of ADR resistant MCF-7/ADR cells and inhibition of MRP gene expression.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMedDate not supplied

Expression of transferrin receptor and ferritin H-chain mRNA are associated with clinical and histopathological prognostic indicators in breast cancer.

It is well known that iron plays an essential role in many biochemical reactions and that rapidly growing cells require more iron for their growth and metabolism than resting cells. Transferrin and its receptor are required for entry of iron into the cell. In contrast, ferritin is a cellular storage protein whose main function is to sequester excess ferric iron and thus prevent high concentrations of soluble ferric iron from becoming toxic to the cell. However, the clinical significance of both transferrin receptor and ferritin mRNA levels have not previously been described in tumors from breast cancer patients. In this study, tumor tissue mRNA levels of transferrin receptor and ferritin were quantitated on forty-two breast cancer patients. A highly sensitive non-radioisotopic cDNA polymerase chain reaction assay was used to quantitate expression of mRNA. The expression of glyceraldehyde-3-phosphate dehydrogenase served as the control. In the tumor tissue from the 42 breast cancer patients the transferrin receptor mRNA levels were significantly correlated to the ferritin H-chain mRNA levels (Spearman correlation r = 0.5433, p = 0.0002; Pearson correlation r = 0.6276, p < 0.0001). The level of amplified transferrin receptor complementary DNA was related to differentiation (ANOVA, p = 0.042) with poorly differentiated tumors having high levels of transferrin receptor mRNA. Further, the levels of amplified gene for ferritin heavy chain complementary DNA was directly related to axillary lymph nodes status (Student's t-test, p = 0.044), presence of metastatic disease (Student's t-test, p = 0.046) and clinical stage (stage I + stage II versus stage III + stage IV; Student's t-test, p = 0.0181). These results demonstrate that non-radioisotopic RT-PCR is a very sensitive method for determining mRNA levels in tumor tissue. Additionally, the quantitation of expression of transferrin receptor and ferritin heavy chain mRNA may be useful for assessing prognosis and guiding therapeutic decisions in breast cancer patients.

Adult↗
PubMedDate not supplied

Influence of interrupted pulmonary lymph drainage on antibody responses in hilar-stripped lungs.

Lung transplantation interrupts hilar lymphatics. This may have an impact on immune responses to antigens entering the lung because the antigens cannot reach the lung-associated lymph nodes where the immune response is generated. We investigated the interruption and regeneration of lymphatics and the influence of this on antibody responses after hilar stripping in rats in three experiments: (1) visual detection of regenerated hilar lymphatics by chromolymphography, (2) observation of transport of carbon particles from the lung to the lung-associated lymph nodes, and (3) assessment of antibody responses after lung immunization with sheep red blood cells. The findings showed that hilar lymphatics were interrupted by hilar stripping and regenerated from day 7 after operation. Transport of particles to the lung-associated lymph nodes was blocked during the first week after operation but returned to normal values thereafter. Serum antibody titers were absent or low in the rats immunized on days 7 and 10 after hilar stripping; subsequently antibody responses gradually recovered in 1 month. We conclude that antibody responses to antigens in hilar-stripped lungs are impaired as long as the antigens cannot be transported through lymphatics from the lung to the lung-associated lymph nodes. These findings can explain in part why pulmonary infections occur so frequently in the initial weeks after lung transplantation.

Animals↗
PubMedDate not supplied

Office visits to ophthalmologists and other physicians for eye care among the U.S. population, 1990.

Despite growth in the use of ophthalmologic care in the last decade, little is known about the use of eye care services and patterns of physician contact across population subgroups. As the U.S. population grows older, such information is crucial in planning strategies for treatment and prevention of eye disorders as well as in identifying potential problems in access and use of eye care. Using the 1990 National Ambulatory Medical Care Survey data, a descriptive statistical analysis was employed to profile the possible variations in eye care-related office visits to ophthalmologists and other physicians across demographic groups. In 1990, a total of 49.3 million visits that were related primarily to an ocular disorder were made to physicians' offices; 43.8 million (89 percent) of these were visits to ophthalmologists and 5.4 million (11 percent) to other physicians. Use of ambulatory eye care varied across demographic subgroups. Those ages 65 or older had a substantially higher rate of eye care related outpatient visits per 1,000 persons per year compared with the rest of the population (743.6 per 1,000 versus 118.5 per 1,000, P < 0.001). Women had a higher rate than men (216.0 per 1,000 versus 177.0 per 1,000, 0.01; P < 0.05). Blacks had a substantially lower rate than whites (143.2 per 1,000 versus 194.6 per 1,000, 0.001; P < 0.01). Those who visited ophthalmologists' offices also differed from those who visited other physicians' offices in terms of their age, sex, race, health insurance status, and disease characteristics. It is important to devote increased attention to the prevention of vision loss among the population groups that have a higher risk of developing eye diseases and that also may have underused or have less access to care. Results from this analysis, in combination with data on the prevalence of ocular disorders for different population groups, provide useful information to identify these high-risk groups.

Adolescent↗
PubMedDate not supplied

Analysis of a new PM motor design for a rotary dynamic blood Pump.

The permanent magnet (PM) motor for a rotary dynamic blood pump requires high power density to coordinate the motor size with the limited pump space and high efficiency to reduce the size and weight of the associated batteries. The motor also serves as a passive axial magnetic thrust bearing, a reacting hydraulic force, and provides a stabilizing force for the radial journal bearing. This article presents analysis of a new PM motor for the blood pump application. High power density is achieved by using the Halbach magnetic array, and high efficiency is accomplished by optimizing the rotor magnet assembly and the stator slots/windings. While both radial and axial forces are greatly enhanced, pulsating components of the torque and force are also significantly reduced.

Biomechanical Phenomena↗