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Biomedical subjects

A Tavakoli

Publications and source records attributed to A Tavakoli.

15 recordsLinked to original sources
PubMed2005

Chlorine residual efficiency in inactivating bacteria from secondary contamination in Isfahan, 2002.

To investigate the inactivation of potential pathogens, we evaluated survival rates for Escherichia coli, Enterococcus faecalis, Aeromonas hydrophila and Salmonella typhi in samples taken from the Isfahan drinking water system. Chlorine residual, pH, temperature and total organic carbon levels were measured. The organism most sensitive to chlorine was A. hydrophila. It was inactived in < 100 minutes at chlorine levels of 0.11 mg/L to 0.90 mg/L. The other 3 organisms showed higher resistance. E. coli tolerated 0.30 mg/L chlorine for > 1000 minutes while Ent. faecalis and S. typhi survived at total chlorine concentration of 0.50 mg/L for 100 minutes. We concluded that total chlorine levels of less than 0.71 mg/L in water supply systems cannot provide the recommended safety levels.

Aeromonas hydrophila↗
PubMed2003

Vlasov model using kinetic phase point trajectories.

A method of solution of the collisionless Vlasov equation by following fixed collisionless phase point ("particle") trajectories (characteristics) in phase space is presented. It solves the coupled Vlasov Maxwell system self-consistently and employs the Leapfrog-Trapezoidal scheme to solve for the characteristics explicitly. It then uses the bilinear finite element interpolation scheme in phase space and maps vital instantaneous phase point information (distribution function) to a fixed background phase space mesh while retaining it at the phase point. The scheme is an enhanced second order one in time and fourth order in space. The code is then used to model a thermal plasma as well as two stream instability using mobile electrons and fixed background ions: the scheme being a momentum conserving one by construction allows energy conservation without assignment of particle shape functions; Langmuir waves are obtained with very good agreement with the Bohm-Gross dispersion relation; the two stream results do not show any numerically induced oscillations attributed to the initial well-ordered velocity distributions. Retention of the characteristics also minimized diffusion. Extensive numerical stability analysis deriving Courant condition for the scheme as well as behavior of computational modes are done in Appendix A, as well as estimating the impact of numerical diffusion in Appendix B. Two to five dimensional versions in phase space exist.

Journal Article↗
PubMed2003

Horseshoe kidney transplantation.

Even though the number of patients awaiting renal transplant is rapidly increasing, the donor pool remains relatively stable. In an attempt to increase this pool, marginal kidneys and kidneys with congenital anatomical variations are being used. Horseshoe kidneys, being the most common renal fusion anomaly, can provide a useful solution to the ever-increasing gap between demand and supply. These kidneys have been successfully transplanted en bloc into a single recipient or, alternatively they have been divided and transplanted into 2 recipients. We report a case of the successful transplantation of an en bloc horseshoe kidney into a single recipient. To the best of our knowledge this is the first of its kind in the U.K. The relevant literature is also reviewed with the aim of raising awareness about the necessity and promising outcomes of such transplants.

Adult↗
PubMed2003

Kidney transplantation into an ileal conduit: a single center experience of 59 cases.

PURPOSE: Congenital and acquired conditions of the lower urinary tract can lead to renal failure requiring transplantation. Under these circumstances transplantation into a urinary diversion or an augmented bladder may be the only option. We report our experience with renal transplantation into ileal conduits in the last 22 years. MATERIALS AND METHODS: Between January 1980 and August 2002, 59 renal transplants were drained into an ileal conduit in 54 patients at our center, accounting for 2.3% of the total number of transplants during this period. Median patient age was 28 years (range 1 to 63) and 13 patients were children. There were 12 living related and 47 cadaveric kidneys transplanted. Spina bifida, the most common cause of end stage renal disease, was seen in 22 patients (41%). Patient and graft survival following transplantation into an ileal conduit were compared with that in the 2,579 other transplants done at this center between January 1980 and December 2001. RESULTS: Actuarial graft survival was 90% at 1 year, 63% at 5 years, 52% at 10 years and 52% at 15 years. Actuarial patient survival was 95% at 1 year, 83% at 5 years, 69% at 10 years and 69% at 15 years. Graft and patient survival was statistically similar to the outcome of the 2,579 other transplants done at our center between January 1980 and December 2001. At a mean followup of 4.6 years (range 0.1 to 20) mean serum creatinine in the 39 functioning grafts was 156 mmol/l. Of the surgical complications 21% were directly attributable to the ileal conduit and it could be considered a risk factor contributing to the complication in a further 39%. Symptomatic urinary tract infection was noted in 65% of the patients, although it did not lead to graft loss. At followup 7 patients had died with a functioning graft. Grafts were lost due to chronic allograft nephropathy in 3 cases, renal artery stenosis in 2, renal vein thrombosis in 2, and acute severe rejection, staghorn calculus and ureteroileal stricture in 1 each. CONCLUSIONS: Kidney transplant drainage into an ileal conduit for urinary diversion is an effective treatment for patients with end stage renal disease due to abnormal lower urinary tracts. Despite preexisting co-morbidity and the increased complication rate long-term graft and patient survival is comparable to that in the normal transplant population.

Adolescent↗
PubMed2001

[Monitoring of oxidative stress after experimental small bowel autotransplantation].

The difficulty at transplanting the small bowel mainly is caused by the biology of the intestine. It is highly immunogenic, is one of the most sensitive tissues to ischemia-reperfusion injury. Our aims were to investigate changes of oxygen free radical mediated reactions after autotransplantation at different preservation times and perfusion fluids. Our results prove that this model is feasible to examine ischemia-reperfusion injury in the small intestine. Euro Collins (EC) is a suitable preserving solution for small bowel transplantation. There was no significant lipid peroxidation within the first 6 hours of graft preservation. However superoxide dismutase (SOD) activity was dramatically reduced during reperfusion in the tissues samples. Significant increase of reduced glutathione at the same time can be explained by compensatory mechanism to neutralize increased free radical production.

Animals↗
PubMed2001

Self-esteem matters: racial & gender differences among rural southern adolescents.

Self-esteem does matter! It matters so much that Oprah dedicated an entire issue of "O" magazine to address the subject. "It's a woman's most treasured possession" (Winfrey, 2000a). Self-esteem has a profound influence on adolescent health promotion behaviors. This study contributes to understanding the role self-esteem plays in the behavior of adolescents. Utilizing a secondary data analysis, race and gender self-esteem differences among adolescents were investigated. The sample of 1,237 students (46% African-American and 52% White) from rural southern areas consisted of 744 females and 493 males. Self-esteem was assessed using the Miller Self-esteem Questionnaire (SEQ). The Hendricks Perceptual Health Promoting Determinants Model (HPHD) provided the theoretical framework for the study. The results of the study revealed a statistically significant difference in various aspects of self-esteem according to race and gender. African-Americans and males had a higher self-esteem which is consistent with many prior studies.

Adolescent↗
PubMed2000

Levels of hope in HIV-infected African-American women of reproductive age.

HIV disease continues to grow at a staggering rate among women, with women of color becoming the group most frequently affected. Previous research has supported hope as an important factor associated with better health, quality of life, recovery from illness, and increased survival in life threatening illnesses such as HIV disease. The purpose of this study was to describe levels of hope in HIV-infected, African-American women, and to examine the relationships among hope and the women's reported symptoms, stage of illness, and perceived relationship with her primary health care provider (PHCP). A descriptive, quantitative design was used. The sample consisted of 49 African-American women 18 to 45 years of age. Face-to-face structured interviews were conducted. Hope was measured using the Herth Hope Scale, and the quality of the relationship with one's PHCP was measured using the Relationship with the PHCP Scale. The level of hope in these HIV-infected women was lower than women with breast cancer and hospitalized adults with cancer. No significant differences were found in level of hope related to relationship status, income, stage of illness, or if a woman had or did not have children. Hope was positively associated with a more positive relationship with the PHCP (r = .33, P = .02). This finding underscores the importance of the quality of the PHCP's relationship with their clients.

Adolescent↗
PubMed1997

Cytogenetic effects of space radiation in lymphocytes of MIR-18 crews.

For assessing health risk, the measurement of physical dose received during a space mission, as well as the LETs, energies and charges of particles is important. It is also important to obtain quantitative information regarding the effectiveness of space radiation in causing damage to critical biological targets, e.g., chromosomes, since at present the estimated uncertainty of biological effects of space radiation is more than a factor of two. Such large uncertainty makes accurate health risk assessment very difficult. For this very reason, a study on cytogenetic effects of space radiation in human lymphocytes was proposed and done for MIR-18 mission. This study used FISH technique to score chromosomal translocations and C-banding method to determine dicentrics. Growth kinetics of cells and SCE were examined to ensure that chromosomal aberrations were scored in first mitosis and were induced not by chemical mutagens. Our results showed that chromosomal aberration frequency of post-flight samples was significantly higher than that of pre-flight ones and that SCE frequency was similar between pre- and post-flight samples. Based on a dose-response curve of preflight samples exposed to gamma rays, the absorbed dose received by crews during the mission was estimated to be about 14.5 cSv. Because the absorbed dose measured by physical dosimeters is 4.16 cGy for the entire mission, the RBE is about 3.5.

Chromosome Aberrations↗
PubMed1996

Radiogenic transformation of human mammary epithelial cells in vitro.

Cancer induction by space radiations is a major concern for manned space exploration. Accurate assessment of radiation risk at low doses requires basic understanding of mechanism(s) of radiation carcinogenesis. For determining the oncogenic effects of ionizing radiation in human epithelial cells, we transformed a mammary epithelial cell line (185B5), which was immortalized by benzo(a)pyrene, with energetic heavy ions and obtained several transformed clones. These transformed cells showed growth properties on Matrigel similar to human mammary tumor cells. To better understand the mechanisms of radiogenic transformation of human cells, we systematically examined the alterations in chromosomes and cancer genes. Among 16 autosomes examined for translocations, by using fluorescence in situ hybridization (FISH) technique, chromosomes 3, 12, 13, 15, 16, and 18 appeared to be normal in transformed cells. Chromosomes 1, 4, 6, 8, and 17 in transformed cells, however, showed patterns different from those in nontransformed cells. Southern blot analyses indicated no detectable alterations in myc, ras, Rb, or p53 genes. Further studies of chromosome 17 by using in situ hybridization with unique sequence p53 gene probe and a centromere probe showed no loss of p53 gene in transformed cells. Experimental results from cell fusion studies indicated that the transforming gene(s) is recessive. The role of genomic instability and tumor suppressor gene(s) in radiogenic transformation of human breast cells remains to be identified.

Breast↗
PubMed1996

Clinical trials: testing of adult chemical heating pad.

Chemical packs are recent innovations in the delivery of dry heat. Because these delivery systems do not have any mechanism for verifying temperature during application, research to determine their safety seems warranted. The purpose of this study was to measure the skin temperature of adults during a 30-minute application of the MediHeat adult heating pad (MH-AHP). Seventy-seven subjects received a 30-minute application of the MH-AHP to their backs while lying in both supine and prone positions. The mean skin temperature in both positions was 101 degrees F. There were significant differences, however, in minimum and maximum skin temperature between positions. Subjects in the prone position had significantly higher maximum skin temperature and significantly lower minimum skin temperature than subjects in the supine position. It is possible that the prone position allows for more air flow over the MH-AHP and that more heat was generated causing the higher maximum temperature. This explanation does not account for the lower minimum temperature. There were no significant differences in perception of heat between the positions at either 5 minutes or 30 minutes. Findings suggest that caution is necessary when applying heating devices that depend on air circulation for heat generation.

Adult↗
PubMedDate not supplied

A validation study using the case-control method of the nursing diagnosis high risk for aspiration.

PURPOSE: To develop further the nursing diagnosis risk for aspiration by determining risk factors present in patients who aspirated. METHODS: The case-control design was used to compare cases (n = 131) and controls (n = 206) on past and present exposures thought to be risk factors for aspiration. Data were analyzed using univariate and multiple logistic regression. FINDINGS: The following risk factors were statistically significant and comprise the final model: altered level of consciousness, metoclopramide (known to accelerate gastric emptying), vomiting, seizures, and unable to change own position. CONCLUSIONS: The risk factors of altered level of consciousness and delayed gastric emptying are currently included in the NANDA taxonomy for the nursing diagnosis risk for aspiration. These risk factors are not included in the taxonomy: vomiting, seizures, and unable to change own position. Results of the study have been submitted to the Diagnosis Review Committee for consideration to further develop this diagnosis.

Analysis of Variance↗
PubMedDate not supplied

Health promoting behaviors among rural southern early adolescents.

A central element in attaining the goals and objectives of Healthy People 2010 is promoting healthy behavior lifestyles. Health promotion continues to be sanctioned as the long term most cost effective approach to a reduction in preventable health problems. Adolescents are presently an age group in jeopardy of making the transition into adulthood with healthy lifestyles. This paper describes the use of the Health Promoting Lifestyle Profile (HPLP) (Walker, Sechrist, and Pender, 1987) as a measure of health promoting behaviors in a group of rural southern early adolescents (1036 seventh and eight graders; 81% were African American). The findings suggest that rural southern adolescents perceive themselves to be enganging in health promoting lifestyle behaviors. However, some HPLP subscales seemed to be especially difficult for adolescents.

Adolescent↗