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Biomedical subjects

S Asfar

Publications and source records attributed to S Asfar.

At least 19 recordsLinked to original sources
PubMed2004

Serum changes in trace elements during thyroid cancers.

The objective was to examine changes in trace elements due to thyroid cancer in humans. Serum levels and tissue contents of trace elements (Zn, Cu, Mn, Mg, Fe and Se) were measured in 43 patients with thyroid cancer before and 4 days after surgery were compared to normal values. The serum levels of zinc in cancer patients were lower than those of normal subjects. Surgical removal of the cancer resulted in the restoration of these levels. Although serum Cu levels in patients were not different from normal, but post-operatively these levels rose significantly (p < 0.001). Levels of Fe, Mg and Mn were significantly lower (p < 0.001) post-operatively. There was no significant change in Serum Se levels. The thyroid tissue contents of these trace elements did not show a difference between the normal (Juxta-tumor) thyroid tissue and the cancerous lesion. Out of the six trace elements examined, the decrease of serum levels of zinc in cancer patients may be linked to the disease condition. It is suggested that this change: (a) may be used to demonstrate successful cancer surgery and (b) may have implications for a long-term follow-up of thyroid cancer patients.

Adenocarcinoma, Follicular↗
PubMed2003

Expression of CD44s in human colorectal cancer.

CD44s is a cell adhesion molecule, which belongs to the family of hyaluronan binding proteins. Anti-body to CD44s is used to establish the association of its expression with the clinicopathological characteristics of colorectal cancer using immunohistochemical methods. The aim of this study is to investigate the expression of the standard form of CD44 (CD44s) in colorectal cancer tissues as compared to adjacent normal colonic tissues. Furthermore, the level of expression of CD44s in colorectal cancer tissues was correlated with the degree of histological differentiation, Duke s classification, sex, size and site of the tumor. Immunohistochemical analysis for CD44s was carried out in 49 paraffin-fixed sections of neoplastic colorectal tissues and non-neoplastic ones adjacent to the lesion, by the standard peroxidase-antiperoxidase method. Expression of these antigens were compared in normal and malignant epithelium and stromal cells. The results show that the level of CD44s in the epithelial and stromal cells was significantly higher in the colorectal cancer tissues than the normal ones. However, there was no association between the percentages of expressions of CD44s and the degree of histological differentiation, Duke s classification, sex or size of the tumor. There was however, a significantly higher expression of CD44s in the epithelium of rectal cancer than that of colonic cancer. This study indicates that the expression of CD44s is significantly higher in colorectal cancer tissues. However, further studies are required to understand its role in tumor progression and metastasis of this disease.

Adult↗
PubMed2002

Cocoon abdomen in a liver transplant patient.

Cocoon abdomen is a rare cause of intestinal obstruction and its pathogenesis remains unclear. This is probably the first report of the development of such a condition in a liver transplant recipient. The management of this patient is discussed and the current literature is reviewed

Humans↗
PubMed2000

Thioacetamide toxicity and the spleen: histological and biochemical analysis.

Exposure to thioacetamide is associated with the development of liver cirrhosis in experimental animals. In addition to liver, thioacetamide toxicity has been observed in other organs. In this study, the toxic effect of thioacetamide on the spleen was investigated at 0, 4, 8 and 12 weeks post-treatment durations. The level of tissue copper and selenium increased until the eighth week when a significant drop was observed. The zinc level was also increased but returned back to normal by week 8, thereafter it showed further increase. Calculation of the copper/zinc ratio showed an increase, but, recovered and returned to normal value by week 12. The level of manganese fluctuated until the eighth week. It then increased rapidly. Histological studies of the spleen tissue showed a significant increase in extramedullary haematopoiesis in the red pulp region and marked hyperplasia in the marginal zone and follicles. The results of this study, demonstrate an intimate association between trace element levels and spleen pathology, as observed in studies of other organs.

Animals↗
PubMed2000

Would measurement of C-reactive protein reduce the rate of negative exploration for acute appendicitis?

BACKGROUND: Appendicectomy for suspected acute appendicitis is a common procedure. The rate of normal appendices unnecessarily removed remains high (15-30%) despite several techniques and investigations used to improve the diagnostic accuracy. Many studies investigated the role of raised C-reactive protein in improving the diagnosis of acute appendicitis, but with conflicting results. This study emphasies the impact of a normal (rather than raised) serum C-reactive protein in reducing the rate of negative explorations. METHODS: In a double blind study, blood for the measurement of serum C-reactive protein (CRP) was collected pre-operatively from 78 patients just before going to the operating room for appendicectomy. The histopathology of the 78 appendices were grouped into positive (acute appendicitis) and negative (normal appendix). White blood count (WBC), CRP and the histopathology findings were correlated. RESULTS: In patients with histopathologically proven acute appendicitis both the WBC count and serum CRP level were significantly raised (P = 0.025 and P < 0.000,1 respectively). Serum CRP level was normal in 13 out of 15 negative explorations (normal appendix on histopathology). The specificity and sensitivity of serum CRP was 86.6% and 93.6%, respectively. CONCLUSION: A normal pre-operative serum CRP measurement in patients with suspected acute appendicitis is most likely associated with a normal appendix. Deferring surgery in this group of patients would probably reduce the rate of unnecessary appendicectomies.

Adolescent↗
PubMed1999

Mechanisms of induction of renal allograft tolerance in CD45RB-treated mice.

BACKGROUND: Rejection is the most significant problem in the field of transplantation. The current goal of transplant immunology is to develop better immunotherapeutic protocols that are aimed at specifically suppressing alloreactivity and preserving an otherwise intact immune system. We have previously shown that mice will accept renal allografts indefinitely with normal renal function after two injections of a monoclonal antibody to the CD45RB protein. Furthermore, this antibody will reverse acute rejection when therapy is delayed until day 4 and will still induce tolerance. The mechanisms of this therapeutic benefit are not known. METHODS: BALB/C mice were used as recipients of major multiple histocompatibility complex-mismatched kidneys using C57BL/6 as donors. Immunoperoxidase microscopy and Northern blots for cytokine gene expression were used to study the renal allografts. Fluorescence-activated cell sorter (FACS) analyses of peripheral blood lymphocytes were performed. Phosphotyrosine peptide phosphatase assays were performed on splenic lymphocyte membranes. RESULTS: A CD45RB monoclonal antibody (MB23G2) induced tolerance and partially depletes peripheral blood lymphocytes. A therapeutically ineffective CD45RB monoclonal antibody (MB4B4) merely coated the circulating lymphocytes. Furthermore, MB23G2 stimulated more tyrosine phosphatase activity than MB4B4 in mouse T-cell membranes. CONCLUSIONS: The clearance of peripheral blood lymphocyte populations and stimulation of protein tyrosine phosphatase activity may be important in the mechanism of tolerance induction by CD45RB therapy, which may be clinically relevant in the therapy of organ rejection in humans.

Animals↗
PubMed1997

Arteritis and increased intracellular calcium as a possible mechanism for tacrolimus-related cardiac toxicity in a pediatric transplant recipient.

We recently reported partially to wholly reversible hypertrophic cardiomyopathy, including severe hypertrophic obstructive cardiomyopathy, as a side effect in pediatric transplant recipients receiving tacrolimus immunosuppression. This seemed to be dose related. We describe a pediatric patient receiving tacrolimus who died 3 weeks after liver/bowel transplantation. Postmortem findings revealed arteritis of cardiac arteries and extensive calcification of cardiac tissue suggesting a possible mechanism of tacrolimus cardiac toxicity. This is consistent with recent reports of tacrolimus increasing calcium release into the sarcoplasmic reticulum of cardiac and striated muscle.

Arteritis↗
PubMed1996

An analysis of late deaths after liver transplantation.

Late deaths (after more than 1 year) after liver transplantation were analyzed in a series of 464 consecutive patients who received liver grafts between 1982 and 1993. Recipients who survived the first posttransplant year (n = 365) had actuarial 5- and 10-year survival rates of 92% and 84%, respectively. Thirty-five patients died between 1.1 and 7.6 years after transplantation (mean, 3.2 +/- 1.9 years). The most common causes of death were related to immunosuppression (40%), namely, chronic rejection, opportunistic infection, and lymphoma. The second most common causes of death were related to the primary disease for which liver transplantation was performed (34.3%), mainly recurrence of hepatobiliary malignancy and hepatitis B. Eight patients (22.9%) died of unrelated and unpredicted causes, most commonly of cardiovascular disease. Although the survival of liver recipients who live beyond the first posttransplant year is excellent, control of rejection and the consequences of chronic immunosuppression are continual threats. Modification of immunosuppression may help in decreasing the mortality of long-term survivors. In addition, better selection of recipients and effective adjuvant therapies (antiviral and antineoplastic) are needed in patients in whom the primary liver disease is notorious for recurrence.

Adolescent↗
PubMed1996

Small bowel transplantation. A life-saving option for selected patients with intestinal failure.

Thirty-seven patients were listed for small bowel transplantation; 16 were transplanted and 15 died while waiting for a donor. Cyclosporine (N = 6) or tacrolimus (N = 10) were used for immune suppression. Graft rejection rates were lower in the combined liver/small bowel grafts than the isolated intestinal transplants (1/7 vs 5/7; P < 0.01) All of the cyclosporine group have died; the median survival was 25.7 months with two patients living more than five years. The tacrolimus group had fewer infections and a shorter hospital stay. All but two are alive with a median survival of 13 months. Seven of eight long-term survivors are off intravenous feedings. We conclude that small bowel transplantation is a life-saving option for patients with intestinal failure who cannot be maintained on total parenteral nutrition.

Adolescent↗
PubMed1995

Pharmacokinetics of a new oral formulation of cyclosporine in liver transplant recipients.

Trough concentrations of cyclosporine can be highly variable because of its poor bioavailability in current oral formulations, Sandimmune (SIM). Neoral (N-SIM) a new microemulsion of cyclosporine is more readily absorbed than SIM in healthy controls. The present study compared the pharmacokinetic profiles of SIM and N-SIM following orthotopic liver transplantation. In 16 patients with partial biliary diversion, 1 week after transplantation, the bioavailability and peak concentration of a single 300 mg dose of N-SIM were greater than SIM by 724% (p = 0.0019) and 800% (p = 0.0001), respectively. In 39 patients who were on stable doses of cyclosporine 1 month after transplantation, the bioavailability of N-SIM was higher than that of SIM under both fasting (+64%, p = 0.001) and fed (+37%, p = 0.004) conditions. Trough concentrations were similar for the two formulations. However, peak concentrations were higher for N-SIM in both fasting (+119%, p = 0.003) and fed (+53%, p = 0.003) patients. Also, time to peak was shorter for N-SIM in both fasting (-21%, p = 0.027) and fed (-59%, p = 0.0001) patients. The correlation between trough concentrations and bioavailability was greater for N-SIM than for SIM in fasted (r = 0.80, p = 0.0001 versus r = 0.75, p = 0.0001) and fed patients (r = 0.65; p = 0.002 versus r = 0.55; p = 0.012). We conclude that the rate of absorption and the bioavailability of N-SIM is significantly and consistently better than SIM and may, therefore, improve the therapeutic index of cyclosporine after liver transplantation.

Administration, Oral↗
PubMed1994

Small bowel transplantation.

After struggling for three decades, SBT is finally emerging as a clinical reality. To become the standard therapy for the treatment of end-stage intestinal failure, SBT must offer a better quality of life, fewer risks, and lower costs than home TPN. To achieve this standard, protocols must be refined to obtain lower rates of rejection and infection as well as more consistent graft function.

Clinical Protocols↗