Congenital midureteric obstruction is a rare entity which can be caused by either ureteric valves or strictures. We report our experience with four patients with midureteric obstruction due to stricture over a six-year period. The condition needs to be differentiated from obstruction of the pelviureteric and vesicoureteric junctions. Obstruction can be initially screened by ultrasound and confirmed by a radionuclide scan with furosemide challenge. Retrograde ureteropyelography and/or intravenous urography may be required to define the level of the stricture.

Hepatitis C virus (HCV) infection is an endemic disease in most hemodialysis (HD) units in Saudi Arabia. We observed that many of our HD patients seroconvert shortly after returning from "holiday dialysis" in other units. We investigated this issue together with other possible factors related to HCV transmission. During the study period, 56 patients were being dialyzed in our unit. Systematic screening was performed on all patients for anti-HCV antibody utilizing ELISA 2.0 and/or RIBA 3.0 and HBsAg every three months together with aminotransferases activity. The same tests were carried out on patients returning from "holiday dialysis" in other units. Test for HCV-RNA was performed in patients with elevated aminotransferases and negative HCV serology. HCV-antibody was positive in 32 patients (57%) of whom 15 (27%) were already positive at the time of starting HD and 17 (30%) seroconverted after starting HD. A total of 24 patients (43%) remained sero-negative. Comparing the sero-converters (SC) to the remained sero-negatives (RSN), the SC had been out for "holiday dialysis" more than the RSN with a mean number of such HD treatments of 16 versus 4 (P= 0.006). The SC had longer duration on dialysis, 38 versus 19 months for the RSN. The two groups did not have significant difference in their age, sex, number of blood transfusions or prior kidney transplantation. Fourteen out of 17 SC (82%) had seroconverted after a mean duration of 100 days from leaving our unit for "holiday dialysis". Eight out of 24 (33%) of the RSN had dialysis outside our unit and remained sero-negative; HCV-RNA confirmed infection in three of them, all of whom had high amino transferase levels. Our study suggests that patients who have "holiday dialysis" in units with high prevalence of HCV-antibody, run a high risk of sero-conversion and may play a role in unit to unit transmission of HCV.

To determine the specificity of flow cytometry based assay for HLA antibody screening prior to transplantation, we evaluated 11 positive sera that were tested by both Flow Panel Reactive Assay (PRA) ^TM class I and class II specific beads after initial FlowPRA ^TM . HLA specificity was compared with previous data from the complement dependent cytotoxicity (CDC) testing of these samples. We found that five samples (22%) were more HLA class II specific (DR- or DQ-) by FlowPRA ^TM than CDC. One sample, negative by FlowPRA ^TM screening, was shown to be HLA class I and class II reactive by FlowPRA ^TM -specific test. Class I specificity was only defined by CDC in this sample. Two other samples, shown to be HLA class I and class II reactive by FlowPRA ^TM screening and FlowPRA ^TM -specific test, were found to be HLA class I reactive only in the first sample and HLA class II reactive only in the second sample by CDC. Our study suggests that FlowPRA ^TM -specific test has higher specificity and sensitivity than CDC in identification of HLA class II specificity than CDC. Nevertheless, FlowPRA ^TM -specific test failed to identify precisely the HLA specificity in samples with broad-spectrum specificity, such as those that have HLA specific antibodies directed against large number of shared epitopes. A software protocol for specificity analysis might help overcome this problem. Also, studies involving larger number of samples are required to validate our findings.

This study was undertaken to compare "direct" and "indirect" nuclear cystography for the detection of vesicoureteral reflux (VUR). Forty-five children (15 males and 30 females), ranging in age from 5 months to 10 years, were studied at the King Hussein Medical Center, Amman, Jordan between January 1998 and December 1999, using both direct (catheter) and indirect techniques of nuclear cystography (NC). Of the 82 ureters that could be compared, 32 ureters were positive for VUR on the direct technique while only 20 ureters showed VUR on the indirect technique (sensitivity 62%). Nine ureters, which did not show VUR on the direct cystogram, were read as positive on the indirect cystogram (specificity 82%). The false positive results of indirect nuclear cystogram make it invalid for VUR screening program, while the ease of assessment and low radiation dose from the direct NC has made this the recommended test for screening and follow-up of VUR.

Allograft rejection remains a major barrier to successful organ transplan­tation. Cellular and humoral immune responses play a critical role in mediating graft rejection. During the last few years, monoclonal antibodies have been used as a new specific therapeutic approach in the prevention of allograft rejection. Recently, the technology of flow cytometry has become a useful tool for monitoring immunological responses in transplant recipients. The application of this valuable tool in clinical transplantation at the present time is aimed at, i) determining the extent of immuno­suppressive therapy through T-cell receptor analysis of cellular components, ii) monitoring levels of alloreactive antibodies to identify high-risk recipients (sensitized patients) in the pre-operative period and iii) to predict rejection by monitoring their development post­operatively. In future, further development of this technology may demonstrate greater benefit to the field of organ transplantation.

Kaposi's sarcoma (KS) has been recently linked with human herpes virus-8 (HHV-8) infection. Other risk factors include the use of cyclosporine and polyclonal anti­lymphocyte sera. Reduction of the immunosuppression, in particular cyclosporine, leads to regression or disappearance of the tumor in a significant number of patients. There are few publications about the response of the tumor to the newer immunosuppressive agent mycophenolate mofetil (MMF). We describe here a 52-year-old woman, who developed KS 22 months after living related transplantation. The sarcoma lesions disappeared after replacing cyclosporine and azathioprine by MMF, while the allograft function remained stable. This case suggests the importance of discontinuation of cyclosporine in the treatment of post-transplant KS. MMF, while maintaining allograft function in the absence of cyclosporine, apparently did not interfere with the regression of the tumor.

Renal excretion and cellular uptake of potassium play key roles in the body's defense mechanism against hyperkalemia. Intra-operative hyperkalemia is an uncommon life-threatening complication during elective renal transplant surgery. We report herewith a non-insulin dependent diabetic kidney transplant recipient with prolonged pre-operative fasting, in whom, despite pre-operative hemodialysis, unforeseen high serum potassium level suddenly presented as wide-complex bradycardia during the surgery. The patient responded well to medical therapy of the hyperkalemia and the surgery was completed uneventfully. It is difficult to single out the exact cause of hyperkalemia in our patient. Prolonged pre-operative fasting for about nine hours, associated with insulinopenia and hyperglycemia, in the presence of β-blockade and metabolic acidosis, have probably collectively resulted in efflux of potassium from intra-cellular stores. This potentially catastrophic complication should be remembered in diabetic patients undergoing any type of surgery.

Methylmalonic acidemia (MMA) is an inborn error of metabolism that results in the accumulation in blood, and increased excretion in the urine of, methylmalonic acid. It may present either as an acute, often fatal, condition in infancy, or in a more chronic intermittent form in older children. Organ involvement including kidneys has been described. We report here the presentation and management of a ten-year-old boy who had MMA and chronic renal failure.

This study was performed to find out the trends in the demand for regular maintenance hemodialysis (HD) and to assess the utilization with reference to selected variables. In a retrospective cohort study, data from a single in-center HD unit of a secondary care hospital located in the south-western part of the Kingdom of Saudi Arabia, were analyzed. Cases of end­stage renal failure (ESRF) registered for regular maintenance HD from the commencement of the HD services in this center (1987 to 2000) formed the subjects of this study. Utilization of the in­center HD was assessed by annual growth rate, death rate, renal transplantation rate and utilization rate. Simple descriptive statistics were used for data analysis. During the study period, 393 cases were registered for regular maintenance HD. There were 183 males (46.6%) and 210 females (53.4%). The mean and median ages of the patients at the initiation of HD were 40.7 and 35 years respectively. Saudis constituted 75.1%(295) over the years studied. The mean annual growth rate, death rate, renal transplantation rate and utilization rate were 7.44, 9.3, 4.33 and 139.57% respectively. Demand for maintenance HD was more from young individuals, which is similar to the national figures. Annual growth rate of those requiring HD was far higher than population growth of this region during the period of study caused primarily by an increased number of new entries coupled with low death and transplantation rates. We conclude that HD utilization studies help to unearth the problems, understand the needs, communicate with the authorities (with facts and figures), find out solutions, and create a network between providers and consumers.