Uptake of HIV testing in a busy South London GU medicine clinic--will we reach targets set in the National Strategy and are we testing those at risk?

We audited the practice of offering, and the uptake of, an HIV antibody test in new genitourinary medicine clinic attenders. We aimed to determine if we have reached targets set in the National Strategy for Sexual Health and HIV for 2006. We also aimed to determine whether patients at higher risk of acquiring HIV infection reached these targets. We found that nearly all patients were offered an HIV test (94.7%) and uptake was 60.5%, demonstrating that we have already reached our target. However, in this audit, the 60% uptake targets were not met by patients at increased risk of HIV, with 52.9% uptake in men who have sex with men and 50% uptake in Black Africans.

A human homolog of angiotensin-converting enzyme. Cloning and functional expression as a captopril-insensitive carboxypeptidase.

A novel human zinc metalloprotease that has considerable homology to human angiotensin-converting enzyme (ACE) (40% identity and 61% similarity) has been identified. This metalloprotease (angiotensin-converting enzyme homolog (ACEH)) contains a single HEXXH zinc-binding domain and conserves other critical residues typical of the ACE family. The predicted protein sequence consists of 805 amino acids, including a potential 17-amino acid N-terminal signal peptide sequence and a putative C-terminal membrane anchor. Expression in Chinese hamster ovary cells of a soluble, truncated form of ACEH, lacking the transmembrane and cytosolic domains, produces a glycoprotein of 120 kDa, which is able to cleave angiotensin I and angiotensin II but not bradykinin or Hip-His-Leu. In the hydrolysis of the angiotensins, ACEH functions exclusively as a carboxypeptidase. ACEH activity is inhibited by EDTA but not by classical ACE inhibitors such as captopril, lisinopril, or enalaprilat. Identification of the genomic sequence of ACEH has shown that the ACEH gene contains 18 exons, of which several have considerable size similarity with the first 17 exons of human ACE. The gene maps to chromosomal location Xp22. Northern blotting analysis has shown that the ACEH mRNA transcript is approximately 3. 4 kilobase pairs and is most highly expressed in testis, kidney, and heart. This is the first report of a mammalian homolog of ACE and has implications for our understanding of cardiovascular and renal function.

Overexpression of the regulatory subunit of gamma-glutamylcysteine synthetase in HeLa cells increases gamma-glutamylcysteine synthetase activity and confers drug resistance.

gamma-Glutamylcysteine synthetase (GCS) is reported to catalyse the rate-limiting step in glutathione biosynthesis, and is a heterodimer composed of a catalytic subunit [heavy subunit (GCSh) of Mr 73000] and a regulatory subunit [light subunit (GCSl) of Mr 31000]. In the present study, we have demonstrated for the first time a potential role for GCSl in resistance towards doxorubicin and cadmium chloride. Addition of recombinant GCSl to HeLa cell extracts in vitro was found to result in an increase in GCS activity of between 2- and 3-fold. Transient transfections of COS-1 cells with the GCSl cDNA cause an increase in GCS activity of approx. 2-fold, and a small but significant (P=0.008) increase in glutathione levels from 126.9+/-4. 2 nmol/mg protein to 178.8+/-19.1 nmol/mg protein. We proceeded to make a HeLa cell line (LN73), which stably overexpresses GCSl. These cells overexpress GCSl approx. 20-fold above basal levels. LN73 was found to have a 2-fold increase in GCS activity (437.3+/-85.2 pmol/min per mg) relative to the control cell line, HL9 (213.4+/-71. 8 pmol/min per mg). In contrast with the transient transfections in COS-1 cells, stable overexpression of GCSl was found not to be associated with an increase in glutathione content. However, when the LN73 and HL9 cells were treated with the glutathione-depleting agent, diethylmaleate, the LN73 cells were found to have an enhanced ability to regenerate glutathione, compared with HL9 cells. The cell lines were treated with various anti-cancer drugs, and their cytotoxicity was examined. No obvious differences in toxicity were observed between the different cell lines following treatment with cisplatin and melphalan. The redox-cycling agent doxorubicin, however, was found to be more toxic (approx. 2-fold) to the HL9 cells than the LN73 cells. When the cells were treated with the carcinogenic transition-metal compound, cadmium chloride, LN73 cells were found to be approx. 3-fold more resistant than HL9 cells.