Relevance of a combined HIV antigen/antibody assay to detect early HIV infections in a low prevalence population: case reports.

The AxSYM HIV Ag/Ab Combo assay (Abbott) has proven to possess excellent sensitivity on seroconversion samples. Since its introduction in Sweden and Norway approximately one year ago, eight cases of acute HIV infections were found earlier compared to assays detecting only antibodies either to screen or to confirm an HIV infection. Data of the presented cases indicate that the early detection of primary HIV infection is of benefit to the individual patient and may reduce further spread of the disease. The impact of HIV combo assays on screening and diagnosis in a low prevalence population is discussed.

Laboratory handling of Helicobacter pylori critically influences the results of in-vitro metronidazole resistance determination.

In-vitro metronidazole resistance rates of Helicobacter pylori determined by Etest are high, and the predictive value of metronidazole resistance is low. It was hypothesised that altered laboratory methods could reduce the overestimation of resistance and improve the predictive value of the Etest. Pre-treatment isolates (n = 150) of H. pylori from 150 patients were investigated by Etest with incubation for 72 h. Treatment with metronidazole, tetracycline and bismuth for 10 days failed to eradicate H. pylori in 23 patients. After isolate storage for 3 years, resistance determination results by agar dilution and Etest, with incubation for 72 and 31 h, were compared. The rate of metronidazole resistance was reduced significantly during storage, and instability of resistance was associated significantly with treatment outcome. Isolates that retained in-vitro resistance had significantly (p 0.008) higher treatment failure rates (n = 13; 42%) than isolates that lost resistance (n = 3; 9%). The reproducibility achieved by dual testing with agar dilution and Etest was 41% and 70% for +/- 1 and +/- 2 log2 dilutions, respectively, after incubation for 72 h, and 85% and 92%, respectively, after incubation for 31 h. Thus, the predictive value was improved from 25% to 50% by the altered laboratory conditions (p 0.04). MIC values of 2-8 mg/L signified an intermediate risk of treatment failure.

An efficient procedure for cloning hormone-responsive genes from a specific tissue.

Nuclear receptors form a superfamily of ligand-activated transcription factors. In contrast to the significant advances made in recent years to dissect nuclear receptor structure and their corresponding function, progress has been rather slow in the identification of target genes for nuclear receptors, information that is a prerequisite for understanding hormone action. Here, we describe a simple screening protocol that makes it possible to efficiently and effectively clone hormone-responsive genes that are specific to a tissue of interest. When this procedure was used to clone prostate-specific and androgen-responsive genes, approximately 40% of the clones selected at random represented genes that are known to be androgen regulated and are largely specific to prostate for expression, such as prostate specific antigen (PSA). A further 37% are known to be highly enriched in prostate for expression, but their androgen regulation is yet to be studied. The rest of the clones represented novel genes, expressed sequence tags, or known genes whose possible androgen regulation has not yet been assessed. This screening scheme can be applied to any hormone/ligand to clone differentially expressed genes specific to a tissue of interest. Identification of such genes and their characterization should greatly facilitate understanding hormone action in normal and pathological conditions.

Full-length cDNA sequence and genomic organization of human NKX3A - alternative forms and regulation by both androgens and estrogens.

NKX3A (NKX3.1) is a recently identified androgen-regulated gene that is largely specific to prostate for expression and likely to code for a homeobox protein. Here we report the full-length mRNA and genomic organization of human NKX3.1. There are at least five different splice variants of NKX3.1 mRNA that result in different open reading frames (ORFs). There is extensive similarity between the human and the mouse NKX3.1 cDNA sequences outside of the ORFs (greater than 60% overall identity), which may be involved in modulating NKX3.1 expression. In addition to its androgen regulation in the prostate cancer cell line LNCaP, we show that NKX3.1 expression is androgen-dependent in the CWR22 prostate cancer xenograft model. Interestingly, NKX3.1 is highly expressed in the androgen-independent derivative CWR22R in the absence of androgens, indicating that it may be deregulated in advanced prostate cancer. Using a Green Fluorescent Protein fusion construct, we show that NKX3.1 is a nuclear protein consistent with its proposed function as a homeobox transcription factor. Furthermore, in addition to androgens, NKX3.1 expression is up-regulated by 17beta-estradiol, but not by progesterone, dexamethasone, or 3,5,3'-triiodothyronine in LNCaP cells. Regulation of NKX3.1 by androgens and 17beta-estradiol in prostate cancer cells and its deregulation in androgen-independent prostate cancer suggest that it may have important regulatory roles during prostate cancer progression.

A novel paired domain DNA recognition motif can mediate Pax2 repression of gene transcription.

The paired domain (PD) is an evolutionarily conserved DNA-binding domain encoded by the Pax gene family of developmental regulators. The Pax proteins are transcription factors and are involved in a variety of processes such as brain development, patterning of the central nervous system (CNS), and B-cell development. In this report we demonstrate that the zebrafish Pax2 PD can interact with a novel type of DNA sequences in vitro, the triple-A motif, consisting of a heptameric nucleotide sequence G/CAAACA/TC with an invariant core of three adjacent adenosines. This recognition sequence was found to be conserved in known natural Pax5 repressor elements involved in controlling the expression of the p53 and J-chain genes. By identifying similar high affinity binding sites in potential target genes of the Pax2 protein, including the pax2 gene itself, we obtained further evidence that the triple-A sites are biologically significant. The putative natural target sites also provide a basis for defining an extended consensus recognition sequence. In addition, we observed in transformation assays a direct correlation between Pax2 repressor activity and the presence of triple-A sites. The results suggest that a transcriptional regulatory function of Pax proteins can be modulated by PD binding to different categories of target sequences.

A cap 'n' collar protein isoform contains a selective Hox repressor function.

We have characterized a protein isoform (CncB) from the Drosophila cap 'n' collar locus that selectively represses cis-regulatory elements that are activated by the Hox protein Deformed. Of the three Cnc protein isoforms, CncB is expressed in a localized pattern in mandibular and labral cells of the head during mid-stages of embryogenesis. When CncB protein is absent or reduced, mandibular cells are homeotically transformed toward maxillary identities. This transformation is associated with persistent Deformed expression in anterior mandibular cells, since the Deformed autoactivation circuit is normally antagonized by CncB function in these cells. Heat-shock-induced ectopic expression of CncB in mid-stages of embryogenesis is sufficient to attenuate the activity of Dfd response elements in maxillary epidermal cells, but appears to have no effect in trunk epidermal cells on either the function or the response elements of other Hox proteins. CncB provides a mechanism to modulate the specificity of Hox morphogenetic outcomes, which results in an increase in the segmental diversity in the Drosophila head.

Accuracy of IgG serology and other tests in confirming Helicobacter pylori eradication.

BACKGROUND: In this study we assessed the accuracy of IgG serology and other tests in confirming Helicobacter pylori eradication. METHODS: The outcome of anti-H. pylori therapy was established by at least two of the following tests: rapid urease test (RUT), culture, 14C urea breath test (non-capsule or capsule UBT), and IgG serology (Orion Diagnostica Pyloriset New EIA-G). RESULTS: Successful H. pylori eradication was confirmed in 698 of 794 patients (88%). The percentage decrease in IgG antibody titre was related to the patients' pre-treatment IgG titre and time interval after treatment. A decrease in IgG titres of 40% or more confirmed H. pylori eradication with 100% specificity, whereas the sensitivity was 82%, 90%, 98%, and 98% 3, 4, 5, and 6 months after therapy, respectively. The 40% cut-off confirmed eradication 3 to 6 months after therapy in 328 of 339 patients (97%) with pre-treatment IgG titres of >700, in 36 of 45 patients (80%) with pre-treatment titres of 300-700, and in 5 of 12 patients (42%) with pretreatment titres of <300. The sensitivity and specificity of the other tests 2 months after treatment were as follows: RUT, 84% and 100%; culture, 88% and 100%; non-capsule UBT, 100% and 89%; and capsule UBT, 100% and 97%. CONCLUSION: A decrease in IgG antibody titre of 40% or more 3 to 6 months after therapy and the capsule 14C UBT at the 2-month follow-up were both highly accurate in confirming H. pylori eradication.

Accuracy of seven different tests for the diagnosis of Helicobacter pylori infection and the impact of H2-receptor antagonists on test results.

BACKGROUND: In this study we compared the accuracy of seven diagnostic tests in diagnosing Helicobacter pylori infection. METHODS: Over 1 year 351 consecutive dyspeptic patients were tested for H. pylori infection by means of antral biopsy specimens for the rapid urease test (RUT), culture, microscopy (acridine stain), and the laboratory urease test (LUT) and, in addition, with 14C urea breath test (UBT), IgG serology, and IgA serology (Orion Diagnostica Pyloriset New EIA-G and New EIA-A). The criterion for H. pylori infection was a minimum of three positive tests. Before being tested, 38% of the patients had used an H2-receptor antagonist (H2RA). RESULTS: Two-hundred and twenty-four patients (64%) were H. pylori-positive. The sensitivity and specificity of the tests were as follows (percentages): RUT, 85, 99; culture, 93, 100; microscopy, 81, 98; LUT, 80, 100; UBT, 95, 95; IgG serology, 99, 91; and IgA serology, 88, 91. The accuracy of the RUT and LUT was reduced in patients receiving H2RA therapy (P=0.04 and 0.01, respectively). CONCLUSIONS: Culture, UBT, and IgG serology were all superior to the other four tests in diagnosing H. pylori infection. Invasive urease-based tests were less accurate in patients receiving H2RAs.

Simplified 10-day bismuth triple therapy for cure of Helicobacter pylori infection: experience from clinical practice in a population with a high frequency of metronidazole resistance.

OBJECTIVE: To evaluate the cure rate of Helicobacter pylori infection, including the impact of in vitro metronidazole resistance (M-R), and the side effects of a simplified 10-day bismuth triple therapy in routine clinical practice. METHODS: From September 1995 to March 1996, 248 consecutive H. pylori-positive patients received 10 days of bismuth subnitrate 150 mg, oxytetracycline 500 mg, and metronidazole 400 mg, all t.id. Before treatment, upper endoscopy, including biopsy specimens for microbiological analysis and IgG serology were performed. M-R was found in 45% of females and 36% of males. At least 2 months after treatment, H. pylori status was assessed by the 14C urea breath test (n = 131), endoscopy (n = 37), urea breath test and endoscopy (n = 63), or solely by IgG serology (n = 7). Ten patients withdrew. IgG serology was performed again after 1 yr. RESULTS: H. pylori infection was cured in 205 patients: 86% by all-patients-treated analysis and 83% by intention-to-treat analysis. When patients were classified according to pretreatment metronidazole susceptibility, cure of infection was achieved in 76% of females harboring M-R strains versus 96% of those with sensitive strains (p = 0.002) and in 81% versus 88% (p = 0.34) of males with M-R versus sensitive strains, respectively. Twelve patients (5 %) had to stop treatment prematurely because of severe side effects, but eight of them were treated successfully. One case of H. pylori infection (0.6 %) was detected at 1-yr follow-up. CONCLUSIONS: Ten-day bismuth triple therapy t.i.d. was effective in curing H. pylori infection in the context of routine clinical practice. The efficacy was reduced in females harboring M-R strains.

A comparison between omeprazole-based triple therapy and bismuth-based triple therapy for the treatment of Helicobacter pylori infection: a prospective randomized 1-yr follow-up study.

OBJECTIVES: To compare the efficacy and side effects of standard bismuth triple therapy with those of omeprazole-based triple therapy in patients with Helicobacter pylori infection and duodenal ulcer disease. METHODS: One hundred patients were prospectively recruited and randomized to receive either bismuth subnitrate 75 mg q.i.d., oxytetracycline 500 mg q.i.d., and metronidazole 400 mg b.i.d. (regimen BTM), or omeprazole 20 mg b.i.d., amoxicillin 750 mg b.i.d., and metronidazole 400 mg b.i.d. (regimen OAM), both for 14 days. Upper endoscopy (with antral biopsy specimens for microbiology and antral and corpus biopsy specimens for histology) was performed before treatment, after 2 months, and again 1 yr after treatment. Serum samples for serology (IgG) were taken. Patients with in vitro metronidazole-resistant (M-R) H. pylori strains were excluded. In a nonrandomized study, 41 patients with M-R strains were given either BTM or OAM. RESULTS: According to intention-to-treat analysis, H. pylori cure rates were 91% and 96% with BTM and OAM, respectively (p = 0.45). In the BTM group, the mean total side effect score was higher (p < 0.001), and more severe side effects were reported (32% vs. 4%, p < 0.001). In the nonrandomized group of patients with M-R strains, H. pylori cure rates were 88% and 67% with BTM and OAM, respectively. All of the successfully treated patients were still H. pylori-negative after 1 yr. CONCLUSIONS: Both treatment regimens were highly effective in curing H. pylori infection in patients with metronidazole-sensitive strains. Omeprazole-based triple therapy was tolerated better than standard bismuth-based triple therapy.

Solid phase technology improves coupled gel shift/footprinting analysis.

For the analysis of protein-DNA interactions by coupled gel-shift/footprinting, DNA fragments need to be extracted from polyacrylamide gels and subsequently separated on high resolution gels. Due to impurities in the extracted DNA, single nucleotide resolution is frequently not achieved. We now describe an improved experimental strategy that employs transient coupling of DNA fragments to a solid support in order to extract DNA of high purity quantitatively, rapidly and reliably. As an example, we describe the application of our protocol to the 'in-gel footprinting' by copper phenanthroline. The method should also find application to the chemical interference assays.

[Diagnosis of Chlamydia trachomatis--culture or enzyme immunoassay? Norwegian multicenter study]. / Diagnostikk av Chlamydia trachomatis--dyrking eller enzymimmunoassay? En norsk multisenterundersøkelse.

Two EIA-tests (Chlamydiazyme, Abbott and Ideia, Celltech) were compared with culture for diagnosis of chlamydial infection in 1,185 patients from four different regions in Norway. The EIA-tests showed only minor differences in prevalences between the different regions (Chlamydiazyme: 4.1% to 5.4%; Ideia: 5.1% to 5.7%), but the agreement between the EIA-results was not satisfactory. 4.6 per cent of the specimens from Trondheim were culture-positive, but only 2.0% of the specimens from the other regions were culture-positive. Compared with the results from cultures from Trondheim (n = 349), the sensitivity, specificity, positive and negative predictive values for the EIA-tests were: Chlamydiazyme: 81.3%, 98.2%, 68.4% and 99.1% (81.3%, 96.4%, 52.0% and 99.1% without blocking test); Ideia: 93.8%, 98.5%, 75.0% and 99.7%. Culture should not be used as a routine method for detection of chlamydia in specimens sent by post without cooling.

The comparative in vitro activity of spiramycin and erythromycin against Norwegian bacterial isolates.

The in vitro activity of spiramycin and erythromycin has been determined by an agar diffusion method against relevant clinical isolates. Generally, erythromycin was more active than spiramycin on a weight-for-weight basis. Spiramycin showed only moderate activity against Haemophilus influenzae and Streptococcus pyogenes. Gonococci were sensitive in vitro to both agents. Many erythromycin-resistant staphylococci were sensitive to spiramycin.

Congenital malaria in Scandinavia.

A case of Plasmodium vivax malaria in a 3-week-old infant, born in Norway of a Pakistanian mother, is reported. The child was admitted with a febrile illness of unknown origin, persistent vomiting, reduced body weight, thrombocytopenia, elevated total level of IgM, and a slightly positive specific IgG antibody titer. The mother had malaria during the puerperium, and febrile episodes 6-8 weeks before parturition. This is the first case of congenital malaria reported from Scandinavia.

Endocarditis caused by Pasteurella multocida.

A 51-year-old previously healthy man developed endocarditis with low grade fever, aortic insufficiently and multiple arterial emboli. An atypical strain of Pasteurella multocida was isolated from each of 3 consecutive blood cultures. Protracted treatment with high doses of penicillin G was necessary to eradicate the infection. Following resection of the damaged aortic valves and implantation of a valve prosthesis, the patient recovered. P. multocida should be regarded as one of the possible causes of subacute bacterial endocarditis.