Place of urolithiasis in the spectrum of urological pathologies, practices and use of endourological procedures in the management of calculi of the upper urinary tract: results of a survey of referral centres in Africa

Our aim was to determine the current trend of endourology in the management of upper urinary tract calculi in Africa reference centres. We conducted an online multiple-choice questionnaire survey involving 46 centres from 27 countries using a structured well-designed Google Form (®) questionnaire. The questionnaires were distributed to the head of service through their emails. The questions collected demographic data about the centre, the epidemiology of urolithiasis, diagnostic means and management of upper urolithiasis, especially access to endourology procedures and their practices. Descriptive analyses were performed. The participation rate was 77.9%. Urinary lithiasis was one of the three main pathologies encountered in 42/46 centres. 33 centres had easy access to CT scanners and 34 had operating theatres equipped with endo-urological surgery equipment. Of these 34 centres, 30 perform endourology for the management of upper urinary tract stones. Rigid ureteroscopy is the main technique used by the centres. It is the only endourology technique used for stone management by 12 centres (40%). 7/30 (23.3%) have the option of performing rigid ureteroscopy, flexible ureteroscopy and percutaneous nephrolithotomy. The frequency of procedures varies widely, with 43.3% rarely performing endourological surgery. Seventeen centres have their operating theatre equipped with a fluoroscope and 6/42 centres have extracorporeal lithotripsy. Open surgery is still used in 29/42 centres (69.1%). Laparoscopy is available in 50% of centres, but none reported performing laparoscopic lithotomy. In Africa, urinary lithiasis plays an important role in the activities of referral centres. Modern management techniques are used to varying degrees (not all centres have them) and with very variable frequency. Open surgery is still widely performed as a management. Rigid ureteroscopy is the main endourological technique. It is essential to develop the practice of modern urology in Africa, mainly endourology.

High frequency of vitamin B12 deficiency in asymptomatic individuals homozygous to MTHFR C677T mutation is associated with endothelial dysfunction and homocysteinemia

The aim of this study was to examine the association of homozygosity for the methylenetetrahydrofolate reductase (MTHFR) C677T mutation and vitamin B12 deficiency in 360 asymptomatic individuals and to investigate forearm endothelial function in C677T homozygotes. MTHFR C677T mutation and levels of vitamin B12, folic acid, and homocysteine were measured in study participants. Frequency of homozygosity for the C677T mutation was 67/360 (18.6%). Homocysteine levels were elevated in homozygous compared with heterozygous subjects or those without the mutation (20.6 +/- 18.8 vs. 9.4 +/- 3.2 mumol/l; P < 0.0001). The number of subjects with vitamin B12 deficiency (<150 pmol/l) was significantly higher among the homozygote than the heterozygote subjects or subjects without mutation [20/67 (29.8%) vs. 27/293 (9.2%); P < 0.0001]. Homozygote subjects had 4.2 times higher probability of having B12 deficiency (95% confidence interval = 2.1-8.3). Forearm endothelial function was assessed in 33 homozygote and 12 control subjects. Abnormal endothelial function was observed in homozygous subjects and was worse in homozygote subjects with vitamin B12 deficiency. Endothelial function was normalized after B12 and folic acid treatment. We found that homozygosity for the C677T mutation is strongly associated with B12 deficiency. Coexistence of homozygosity for the C677T mutation and B12 deficiency is associated with endothelial dysfunction and can be corrected with vitamin B12 and folic acid treatment.

Telomerase activity and cytokeratin 20 as markers for the detection and followup of transitional cell carcinoma: an unfulfilled promise

PURPOSE

Telomerase activity compensates for the erosion of chromosomes and it has been detected in a wide variety of human tumors. Cytokeratin 20, an intermediate filament of epithelial cells, is expressed particularly in the urinary tract. These 2 molecules are candidates to become markers for the detection and followup of bladder carcinoma. We evaluate whether each molecule may serve as a potential marker and whether the 2 combined would improve the detection or followup of bladder carcinoma in a noninvasive manner.

MATERIALS AND METHODS

We obtained 44 morning urine samples from patients with transitional cell carcinoma patients and 26 from age matched patients with a wide variety of clinical disorders but no malignancy of any kind. A telomerase polymerase chain reaction-enzyme-linked immunosorbent assay kit was used to determine telomerase activity and cytokeratin 20 expression was determined by nested reverse transcriptase-polymerase chain reaction.

RESULTS

All samples tested positive for cytokeratin 8 expression, which verified epithelial cells in the urine samples. Of the 44 transitional cell carcinoma cases of all stages and grades 37 (84.1%) were positive for telomerase activity, 36 (81.8%) were positive for cytokeratin 20 expression and 65.9% were double positive. Of the 29 controls with various clinical conditions other that malignancy 22 (75.9%) were positive for telomerase activity, 13 (44.83%) were positive for cytokeratin 20 expression and 34.6% were double positive.

CONCLUSIONS

Telomerase activity and cytokeratin 20 expression are not specific for malignancy and may be detected in many nonmalignant pathological conditions. Therefore, their use as potential markers of bladder carcinoma should be carefully reevaluated.

Urinary cytokeratin 20 as a marker for transitional cell carcinoma

OBJECTIVES

To determine if detection of cytokeratin 20 (CK20) gene expression, by reverse transcriptase-polymerase chain reaction (RT-PCR) in urine from transitional cell carcinoma (TCC) patients, can provide a new noninvasive tool for the follow-up of patients with urothelial carcinoma of the bladder.

METHODS

Urine was collected from 95 patients previously diagnosed as TCC during their follow-up, and from 27 healthy volunteers. All patients had a transurethal resection of tumor or biopsies obtained from 'suspicious' areas in the bladder. RNA was extracted from cells collected from the urine and RT-PCR was performed with specific primers for the amplification of cytokeratin 8, a general marker for epithelial cells, and of CK 20, a marker for TCC urothelium.

RESULTS

CK20 expression was detected in 86.7% of TCC patients, and only in 3.3% of healthy volunteers (specificity 96.7%). Strong correlation was found between tumor grade and expression of CK20 in urine. All grade III and IV tumors demonstrated positive CK20 expression (100% sensitivity), whereas the sensitivity for lower grades was between 71 and 80%. Among 11 patients with a previous biopsy-proven diagnosis of TCC and a current negative biopsy, in 9 patients CK20 expression was detected. Further follow-up of these patients for a period of 6 months revealed recurrence of TCC in 4 patients.

CONCLUSION

CK20 detection in urine cells is a simple, noninvasive method with a high potential to become the marker of choice for monitoring and follow-up of TCC patients. More information is needed regarding CK20 expression in nonmalignant urological disease, to evaluate its use for routine screening purposes.

Activated protein C resistance (factor V Leiden) associated with thrombosis in pregnancy

OBJECTIVE

Our purpose was to evaluate activated protein C resistance phenotype and genotype among patients with thrombosis during pregnancy and the puerperium.

STUDY DESIGN

This observational study was conducted prospectively during a 2-year period (July 1993 to June 1995) in a preselected population. All patients admitted to our high-risk pregnancy unit with a diagnosis of deep vein thrombosis, pulmonary emboli, transient ischemic attack, and cerebrovascular accident during pregnancy and the puerperium were included. Prothrombin time, partial thromboplastin time, fibrinogen levels, protein C, protein S, antithrombin III, functional test for activated protein C resistance, and factor V Leiden mutation by polymerase chain reaction were performed on each patient.

RESULTS

Fifteen patients were included. Seven (46.6%) patients were positive for activated protein C resistance (factor V Leiden). All other coagulation studies were negative for all patients. All patients with activated protein C resistance had a venous thrombotic event, deep vein thrombosis, or pulmonary emboli, and only one had a cerebrovascular accident on the basis of sagittal sinus thrombosis. Only two of the activated protein C resistance-negative patients had venous thrombosis (pulmonary emboli). The remaining six patients had transient ischemic attacks or cerebrovascular accidents. For the subgroup with venous thrombosis during pregnancy and the puerperium, the incidence of activated protein C resistance (factor V Leiden) was 78%.

CONCLUSION

This study demonstrates the incidence of factor V Leiden in a selected population in whom thrombotic events developed during pregnancy and the puerperium. This small-scale study provides justification for a large cohort study that will identify women with factor V Leiden and determine their risk for thrombosis during pregnancy and the puerperium. We believe that factor V Leiden should be evaluated in conjunction with thrombotic events in the pregnant woman.

Erythropoietin-independent colonies of red blood cells and leukocytosis in a worker exposed to low levels of benzene

BACKGROUND

Exposure to high levels of benzene commonly results in the suppression of hemopoiesis, although cases of leukocytosis and leukocytosis with thrombocytosis have been reported. No hematologic abnormalities have generally been found with exposure to low levels of benzene.

METHODS

A pipe fitter exposed to low levels of benzene (time-weighted average 0.9 ppm) developed leukocytosis. His blood counts and growth of erythroid burst forming units (BFU-E) was followed with and without the addition of erythropoietin.

RESULTS

Erythropoietin-independent BFU-E colonies were increased to 40 per 4 x 10(4) cells (normal < 3 per 4 x 10(4) cells). Both the leukocyte count and the number of erythropoietin-independent BFU-E colonies decreased when exposure to benzene was terminated. On reexposure the white blood count again increased. After the work was terminated, the white blood count returned to normal, as did the number of erythropoietin-independent BFU-E colonies, over a period of 12 months.

CONCLUSIONS

Our findings suggest that even low levels of benzene can result in perturbations of the hemopoietic system. Further studies are warranted to determine whether these findings are idiosyncratic, coincidental, or a more general phenomenon.

Soluble factors from peripheral blood T-cells of patients with polycythemia vera stimulate normal BFU-E

T cells and monocytes from patients with polycythemia vera (PV) were isolated and grown in culture. The conditioned medium was tested for the presence of soluble factors that promote proliferation of erythroid colonies from the blood of healthy donors. We show that T cells from all 14 PV patients that were examined secrete factor/s that stimulate the proliferation of erythroid burst-forming units (BFU-E) in the absence of an external source of erythropoietin and BPA. Addition of cyclosporin A to the culture did not inhibit the production of this activity. The conditioned medium from monocytes of PV patients can also stimulate normal BFU-E but to a much lesser extent than T-cell conditioned medium. Such stimulation was not observed with control T cells or monocytes. We observed that the fraction of DR-positive T cells was significantly higher in PV patients comparing to normal. These results suggest that PV patients possess an abnormally high level of circulating activated T cells which may in turn be the source of the putative factor that facilitates uncontrolled erythroid differentiation.

Retroviral-mediated gene transfer into CD34-enriched human peripheral blood stem cells

Retroviral-mediated gene transfer has been shown to be a feasible method for the introduction of new genes into bone marrow hematopoietic stem cells. We have investigated the application of this technology to primitive CD34-enriched human peripheral blood cells as a potential alternative stem cell source. Bone marrow (BM) and peripheral blood (PB) CD34-enriched cells from normal volunteers and patients with multiple myeloma were exposed to retroviral vectors containing the neomycin-resistance gene and gene transfer efficiency into colony-forming unit colonies (CFU-C) and CD34+ cells was assessed by polymerase chain reaction (PCR). Peripheral blood was a target equally efficient to BM, and PB cells mobilized with chemotherapy and growth factors were also shown to take up retroviral vectors readily. Conditions favoring gene transfer were investigated, and exposure of cells to interleukin-3 (IL-3), interleukin-6 (IL-6), and stem cell factor (SCF) during a 72-hour transduction was found to be most effective. The use of PB stem cells as targets for gene transfer could allow repeated collections and transductions, with obvious advantages over a single BM collection.

Evidence for the existence of circulating monoclonal B-lymphocytes in multiple myeloma patients

Multiple myeloma is characterized by the proliferation of a single clone of plasma cells producing a homogeneous immunoglobulin fraction. In this disease, plasma cells home essentially in the bone marrow. However, controversy exists whether peripheral blood B-lymphocytes in patients with multiple myeloma (MM) are part of the malignant clone. We investigated clonal immunoglobulin gene rearrangement (IgGR) in T-cell-depleted peripheral blood mononuclear cells as well as in bone marrow of these patients. Seven out of 17 MM patients demonstrated an identical IgGR in bone marrow and peripheral mononuclear cells, these patients were in an active stage of the disease. In nine patients in plateau phase, clonal IgGR could not be detected in peripheral blood. Peripheral mononuclear cells from ten patients with monoclonal gammopathies of undetermined significance (MGUS) were also examined and no IgGR was detected. The existence of monoclonal B-lymphocytes in the circulation of patients with MM suggests a mechanism whereby the malignant clone homes in the bone marrow through peripheral blood. These findings may also be used for the evaluation of patients with active myeloma and the determination of plateau phase.

Effect of adherent cells on the regulation of BFU-E in patients with myeloproliferative disease

The interaction between adherent cells and red cell progenitors from peripheral blood of patients with polycythemia vera (PV), essential thrombocytosis (ET), and healthy controls was studied. Various combinations of adherent and nonadherent cells were co-cultured in a semisolid system. Adherent cells from controls, when added at low concentrations, stimulated BFU-E proliferation, whereas high concentrations (40% of total cells in the culture) caused a significant decrease in the number of BFU-E colonies in 6/8 PV patients, 4/4 ET patients, and 8/12 controls. On the other hand, low and high concentrations of adherent cells from both patients with PV and ET caused a significant increase in BFU-E from either patients or controls. Moreover, adherent cells from these patients induced endogenous BFU-E proliferation (independent of erythropoietin) in nonadherent cells of 12/12 normal controls. The results show that BFU-E from patients with PV and ET are sensitive to suppression by normal adherent cells. On the other hand, adherent cells from these patients possess stimulatory activity on BFU-E from peripheral blood at all concentrations and are devoid of the inhibitory activity. This suggests a possible defect in the functioning of adherent cells in PV and ET patients which may contribute to the abnormal regulation of hematopoiesis in these disorders.

pHG165: a pBR322 copy number derivative of pUC8 for cloning and expression

During the construction of the Messing pUC plasmid series, the rop(rom) gene of pBR322 which mediates the activity of RNAI was deleted. This has resulted in an elevated copy number for the pUC plasmids which makes the expression of beta-galactosidase activity constitutive in a host containing the Iqtss lac repressor. We describe the construction of a new series of vectors which retain the pUC multiple cloning site (MCS) but in which copy number control has been recovered. In addition, the lac alpha/lac promoter expression region has been inserted into a HpaI cassette. This facilitates the movement of recombinant DNA clones within the MCS. It also increases the complementation activity of the lac alpha peptide by an order of magnitude, allowing selection of recombinants by their Lac- phenotype on MacConkey agar.

Specific DNA sequences associated with the nuclear matrix in synchronized mouse 3T3 cells

Eukaryotic chromatin appears to be organized into arrays of supercoiled loops anchored to the scaffolding structure of the mitotic chromosome core or to the nuclear matrix of interphase nuclei. To reveal whether specific DNA sequences are involved in this level of chromatin organization, we isolated and cloned a population of DNA molecules [average length of 150 base pairs (bp)] closely associated with the nuclear matrix after exhaustive DNase digestion and subsequent extensive protease digestion. The nuclear matrix was obtained from murine BALB/c 3T3 cells synchronized at the G1/S border of the cell cycle. We report the structure of two sequences, designated G4 and G5, which are highly enriched in the matrix DNA. Sequence G4, of 152 bp, contains three 31-bp direct head-to-tail repeats. An 11-bp sequence at the end of each repeat is homologous to the first large tumor antigen recognition site of human papova virus. Sequence G5, of 135 bp, consists of two well-defined domains, in which the first domain is a fragment of the B1 repetitive sequence. The results suggest the possibility that the loops of histone-depleted chromatin are connected to the scaffold of the nuclear matrix, with specific DNA sequences at the anchorage sites.