RENIN GENE POLYMORPHISM ASSOCIATED WITH ALDOSTERONE RESPONSIVENESS TO THE RENINANGIOTENSIN SYSTEM IN PATIENTS WITH ALDOSTERONE-PRODUCING ADENOMAS

1. Aldosterone levels in patients with unilateral aldosterone-producing adenomas may be responsive or unresponsive to the renin-angiotensin system, with the former often previously misdiagnosed as bilateral adrenal hyperplasia. 2. In tumours from patients in the responsive subgroup, renin mRNA is expressed in greater amounts than in tumours from patients in the unresponsive subgroup, or in normal adrenals. 3. We compared the frequency of four renin gene polymorphisms in peripheral blood DNA from the two subgroups and found significant associations between BglI, TaqI and HinfI restriction fragment length polymorphisms (RFLP) and aldosterone responsiveness. 4. Allelic variation in the constitutive renin gene was associated with a specific cause of hypertension.     

Susceptibility to ketoconazole of Candida albicans strains from sequentially followed HIV-1 patients with recurrent oral candidosis

The MIC values of the antifungal drug ketoconazole were evaluated on 66 Candida albicans strains. These strains were isolated from 26 HIV-1 infected patients with oral recurrent candidosis. Each episode of oral candidosis observed in these patients was orally treated with ketoconazole (200 mg/day) until the clinical disappearance of the lesions. The most frequent MIC values were 20 micrograms/ml and 10 micrograms/ml, observed in 37 and 19 isolates respectively. Only strains from five patients showed changes in their susceptibility to ketoconazole. This fact could indicate that a different strain causes the subsequent reappearance of the oral lesions, rather than the drug selecting resistant fungal strains. Our results stress the role of host characteristics in the occurrence of candidal infections, pointing to the progressing failure of the immunological response as the most important factor responsible for the recurrence of oral candidosis during HIV-1 infection.     

DNA probe technology: implications for service planning in Britain

For certain genetic conditions DNA testing identifies carriers and determines the risk status of foetuses, thus helping parents to make more informed prenatal decisions. Data, collected from three genetic centres in England and Wales from August 1986 to July 1990, are used to describe trends in demand for DNA testing, the impact of DNA tests on carrier risk assessment, and the use of DNA tests in relation to pregnancy outcome. Altogether the data include 23,388 subjects and 681 pregnancies in 8738 families divided into five cohorts by year of entry and referral. The most frequent gene disorders referred to the genetic centres are currently being tested or will soon be tested. For these disorders the initial high level of activity has declined and may have reached steady state. Demand for DNA services is high for cystic fibrosis and Duchenne muscular dystrophy, intermediate for Huntington's disease, and low for adult polycystic kidney disease, phenylketonuria and tuberous sclerosis. Based on these findings we suggest that demand for DNA tests will be high in serious, untreatable and slow progressing conditions with early onset; intermediate for conditions affecting intellect and neurological integrity with later onset; and low for treatable, late-onset conditions, or those for which there is evidence of heterogeneity, and variable penetrance. It would be helpful to assess the extent to which this view of demand is confirmed when the new disorders being DNA tested are considered and for the pattern of activity of DNA testing for some types of cancer. Since no DNA centre could offer a fully comprehensive testing service, it is recommended that a structure is created to audit overall activity, assist in policy formulation, and influence supraregional service organisation, in order that the spread of DNA services be planned as effectively as possible. This structure would facilitate monitoring of the evolution of contract specifications agreed by commissioners and providers on a regional basis.     

Exercise tolerance after anaemia correction with recombinant human erythropoietin in end-stage renal disease

The aim of this study was to evaluate the effect of correction of chronic anaemia on the physical performance and the cardiovascular response to effort in children with end-stage renal disease (ESRD) maintained by haemodialysis. Seven patients (mean age 13.9 years) underwent triangular-type treadmill exercise testing before [haemoglobin (Hb) 6.3±0.9 g/dl] and after (Hb 11.2±1.2 g/dl) anaemia correction with recombinant human erythropoietin (rHuEPO). After treatment, the work-load reached, the peak oxygen uptake and average ventilatory anaerobic threshold (VAT) values were significantly increased (P<0.01,P<0.001,P<0.05 respectively). VAT values, expressed as a percentage of normal values, increased from 55.7±16.6% to 82.4±21%. This improvement correlated well with the increase in Hb (r=0.79). Oxygen pulse also increased significantly, when tested after anacmia correction. In conclusion, these data demonstrate that when the anaemia of children with ESRD is corrected with rHuEPO, there is a clear improvement in acrobic work capacity and effort tolerance.     

Gastroesophageal reflux disease (GERD), extraesophageal reflux (EER) and recurrent chronic rhinosinusitis

Chronic polypoid rhinosinusitis (CRS) is a common disease, affecting approximately 16% of the adult population in the US every year. In addition to many well known predisposing factors, an association with reflux disease is hypothesized. Such an association might explain the recurrence of polyposis in the face of improved surgical techniques and postsurgical treatment of CRS. At present it is unclear whether extraesophageal reflux directly injures the sinus mucosa, whether gastroesophageal reflux leads to vagus-mediated neuroinflammatory changes, or whether both mechanisms occur separately or simultaneously. In patients suffering from recurrent CRS (n=20) and healthy volunteers (n=20), ambulatory 24 h two channel pH testing was performed. The number of reflux events, the fraction of the total time during which pH was below 4, and the reflux area index (RAI) were determined in the esophagus as well as in the hypopharynx. Patients with recurrent CRS had significantly more reflux events in the esophagus and the fraction of pH<4 and the RAI were increased up to 10-fold compared to healthy volunteers. In contrast to the esophagus, these differences were not observed in the hypopharynx. Recurrent CRS is often associated with GERD but not with EER. Recurrent disease or prolonged recovery after surgery should raise the suspicion of reflux disease as a possible triggering factor. Because GERD itself cannot be diagnosed by laryngoscopy, and because of the subjectivity of symptoms such as heartburn, the otolaryngologist should consider double-probe pH testing as the diagnostic procedure of choice.     

Epstein-Barr virus DNA in Reed-Sternberg cells of Hodgkin''s disease is frequently associated with CR2 (EBV receptor) expression

We studied 44 cases of Hodgkin's disease for the presence of Epstein-Barr virus (EBV) DNA, its localization and the expression of the EBV receptor on the tumour cells. EBV DNA was found in 52% (16/31) of the Hodgkin's lymphomas using the polymerase chain reaction. With a very sensitive non-radioactive DNA in situ hybridization technique in combination with immunohistochemistry for CD 30 or CD 15 antigens, EBV DNA was localized to Reed-Sternberg cells and its mononuclear variants. The relationship between the presence of EBV DNA and the expression of the EBV-receptor CR2 (CD 21) on Reed-Sternberg cells was studied using the same techniques and two different monoclonal anti-CD 21 antibodies. CR2 could be detected on a substantial number of the Reed-Sternberg cells in EBV DNA positive Hodgkin's lymphomas (9/12; 75%), whereas in EBV negative cases positivity with anti-CD 21 was rare (1/13; 8%). The results indicate that CR2 expression on Reed-Sternberg cells and the presence of EBV DNA sequences are frequently associated in Hodgkin's lymphomas.     

A quantitative analysis of valgus torque on the ACL: a human cadaveric study.

The loads needed to elicit a positive pivot shift test in a knee with an anterior cruciate ligament (ACL) rupture have not been quantified. The coupled anterior tibial translation (ATT), coupled internal tibial rotation (ITR), and the in situ force in the ACL in response to a valgus torque, an inherent component of the pivot shift test, were measured in 10 human cadaveric knee specimens. Using a robotic/universal force-moment sensor testing system, valgus torques ranging from 0.0 to 10.0 Nm were applied in nine increments on the intact and ACL-deficient knee in flexion ranging from 0 degrees to 90 degrees. At 15 degrees of knee flexion, the coupled ATT and ITR were significantly increased in the ACL-deficient knee when compared to the intact knee. Coupled ATT increased a maximum of 291% (6.7 mm, p<0.05), while coupled ITR increased a maximum of 85% (5.1 degrees, p<0.05). At 30 degrees, the increases in coupled ATT and ITR were significant at valgus loads of 3.3 Nm and greater with a maximum increase in coupled ATT of 137% (6.3 mm, p<0.05) and a maximum increase in coupled ITR of 38% (3.6 degrees, p<0.05). At 45 degrees, coupled ATT increased significantly (maximum of 69%, 4.4 mm, p<0.05), but only at torques > or =6.7 Nm. The in situ force in the ACL was less than 20 N for all flexion angles when a torque between 3.3 and 5.0 Nm was applied. Low valgus torque elicited tibial subluxation in the ACL-deficient knee with low in situ ACL forces, similar to a positive pivot shift test. Thus, application of a valgus torque may be suitable to evaluate ACL-deficient and ACL-reconstructed knees, since subluxation can be achieved with minimal harm to the ACL graft. This work is important in understanding one load component needed for the pivot shift examination; further studies quantifying other load components are essential for better comprehension of the in vivo pivot shift examination.     

Standardized molecular typing of Candida albicans strains

Summary. A method is presented for the standardization of Candida albicans DNA fingerprinting, which is based on Southern hybridization of Eco RI-digested chromosomal DNA with the moderately repetitive DNA element CARE-2 and the subsequent rehybridization of the blots with a molecular size marker also included in each DNA sample. This method resulted in extremely precise alignment of all strain-specific CARE-2 hybridization patterns, even when analysed on different gels, and will enhance the accuracy of genetic relationship determinations in epidemiological studies including large numbers of strains.
Zusammenfassung. Zur Standardisierung des DNA-Fingerprinting von Candida albicans wurde eine Methode entwickelt, die auf der Southern Hybridisierung Eco RI-gespaltener chromosomaler DNA mit dem mittelrepetitiven DNA-Element CARE-2 und der darauffolgenden Rehybridisierung der Blots mit einem auch in den Proben enthaltenen molekularen Größenmarker beruht. Dies resultierte in einer äußerst präzisen Größen-bestimmung der hybridisierenden Fragmente, so daß alle stammspezifischen CARE-2-Hybridisierungsmuster exakt verglichen werden konnten, auch wenn die Isolate auf verschiedenen Gelen analysiert wurden. Die Methode erhöht die Genauigkeit der Bestimmung genetischer Verwandtschaftsbeziehungen in epidemiologischen Untersuchungen, in denen eine große Anzahl von Stämmen analysiert wird.     

Genetic analysis of the yeast NUD1 endo-exonuclease: a role in the repair of DNA double-strand breaks

The deoxyribonucleases (DNases) have been shown genetically to be important in the vital processes of DNA repair and recombination. The NUD1 gene, which codes for an endo-exonuclease of Saccharomyces cerevisiae, was analyzed for its role in the DNA double-strand break (DSB) repair processes. While the nud1 strain is only slightly sensitive to ionizing radiation, expression of the HO-endonuclease to introduce a DSB at the MAT locus in that strain results in cell death. Cell survival is inversely proportional to the duration of HO-endonuclease expression. Analysis of the surviving colonies from the nud1 strain indicated that many of the survivors are sterile and that the proportion of these sterile survivors increases with the time of HO-endonuclease expression. On the other hand, the surviving colonies from the isogenic NUD1 strain are mating-proficient. Interestingly, double mutants of nud1 rad52 are more resistant to ionizing irradiation than the rad52 strain and have a cell-survival fraction of 32% for rad52-1 nud1 and 9% for rad52::URA3 nud1 following prolonged HO-endonuclease expression, indicating that nud1 has a suppressor effect on the DSB-induced lethality in rad52. Polymerase chain reaction analysis showed that many of the nud1 survivors contained small alterations within the MAT locus, suggesting that the survivors arose through the process of non-homologous end-joining. These results suggest that the endo-exonuclease acts at a DSB to promote DNA repair via the homologous recombination pathway. Received: 20 July / 20 September 1998