Visceral leishmaniasis in a German child who had never entered a known endemic area: case report and review of the literature

We describe a case of visceral leishmaniasis in a 15-month-old German child. Diagnosis was significantly delayed because the patient had no history of travel to known endemic areas. Congenital or blood transfusion-associated leishmaniasis was ruled out. Possible modes of transmission (including a potential new autochthonous focus of the disease in central Europe) are discussed.

Primary treatment of cervical carcinoma. Ten years experience from one Norwegian health region

OBJECTIVE

To study the primary care of cervical carcinoma with regard to clinical and pathological factors, treatment decisions, complications and survival.

DESIGN

A historical cohort comprising all women hospitalized with invasive cervical carcinoma (n=293) during the period 1987-1996.

RESULTS

Median age was 52 years (range 23-90). FIGO stage distribution was 62%, 15%, 18% and 5% in stages I, II, III and IV, respectively. Early stage disease correlated with young age. Histologic types were: squamous cell carcinoma 84%, adenocarcinoma 11%, adenosquamous carcinoma 4% and small cell/anaplastic carcinoma 1%. Primary therapies were: surgery 188 women (64%), radiotherapy 99 women (34%), chemotherapy two women (0.7%); four women not treated (1.3%). Complications after surgery in 25 women (13%), none were fatal. Acute or late complications after primary or postoperative radiotherapy in 39 women (25%), seven (4.6%) were late serious complications. Three women died from complications related to radiotherapy. Mean follow-up of surviving patients was 58 months. Overall disease specific five-year survival was 70%. Five-year survival in stages IA, IB, II and III was 100%, 88%, 58% and 20%, respectively. One-year survival in stage IV was 31%. Median survival in stages III and IV according to curative or palliative aim of treatment was 20 and 6 months, respectively (p<0.005).

CONCLUSION

Satisfactory quality of diagnosis and therapy have been maintained through regional care for cervical cancer patients.

A novel polymorphism in the toll-like receptor 2 gene and its potential association with staphylococcal infection

The toll-like receptor 2 (TLR2) has gained importance as a major mammalian receptor for lipoproteins derived from the cell wall of a variety of bacteria, such as Borrelia burgdorferi, Treponema pallidum, and Mycoplasma fermentans. We were interested in identifying mutations in the TLR2 gene that might prove to be associated with altered susceptibility to septic shock. We performed a mutation screen of the TLR2 gene using single-stranded conformational polymorphism in 110 normal, healthy study subjects and detected an Arg753Gln mutation in three individuals. No other missense mutations were detected in the TLR2 open reading frame. Functional studies demonstrate that the Arg753Gln polymorphism, in comparison to the wild-type TLR2 gene, is significantly less responsive to bacterial peptides derived from B. burgdorferi and T. pallidum. In a septic shock population, the Arg753Gln TLR2 polymorphism occurred in 2 out of 91 septic patients. More importantly, both of the subjects with the TLR2 Arg753Gln polymorphism had staphylococcal infections. These findings suggest that a mutation in the TLR2 gene may predispose individuals to life-threatening bacterial infections.

Evaluation of the growth dynamics of Trichophyton rubrum cultures by morphometry and non-linear curve fitting analysis

To determine the size of dermatophyte thalli, a point-counting procedure with a square lattice grid is proposed instead of using the one-dimensional diameter as the size parameter. For an analysis of the growth dynamics of such colonies, the area values might be subjected to a non-linear curve-fitting procedure. To demonstrate the method, samples of 15 Trichophyton rubrum strains, isolated from human skin and cultured concomitantly on Sabouraud and Selective agar during a period of 8 weeks, were used. The morphometric assessment of the area of the thalli, subjected to non-linear curve fitting, disclosed only a slight difference in the growth dynamics.

TLR4 mutations are associated with endotoxin hyporesponsiveness in humans

There is much variability between individuals in the response to inhaled toxins, but it is not known why certain people develop disease when challenged with environmental agents and others remain healthy. To address this, we investigated whether TLR4 (encoding the toll-like receptor-4), which has been shown to affect lipopolysaccharide (LPS) responsiveness in mice, underlies the variability in airway responsiveness to inhaled LPS in humans. Here we show that common, co-segregating missense mutations (Asp299Gly and Thr399Ile) affecting the extracellular domain of the TLR4 receptor are associated with a blunted response to inhaled LPS in humans. Transfection of THP-1 cells demonstrates that the Asp299Gly mutation (but not the Thr399Ile mutation) interrupts TLR4-mediated LPS signalling. Moreover, the wild-type allele of TLR4 rescues the LPS hyporesponsive phenotype in either primary airway epithelial cells or alveolar macrophages obtained from individuals with the TLR4 mutations. Our findings provide the first genetic evidence that common mutations in TLR4 are associated with differences in LPS responsiveness in humans, and demonstrate that gene-sequence changes can alter the ability of the host to respond to environmental stress.

Effect of clarithromycin and omeprazole therapy on the diversity and stability of genotypes of Helicobacter pylori from duodenal ulcer patients

The genotypes of multiple isolates of Helicobacter pylori from 17 duodenal ulcer patients in the United Kingdom were compared to determine reasons for treatment failure. Isolates were from antrum and corpus biopsies taken before and after dual therapy with clarithromycin and omeprazole. All isolates were tested for antibiotic resistance and characterised by a novel scheme combining polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of the ureA + ureB and 23S rRNA genes, vacA signal and midregion genotypes, and PCR detection of cagA. Combined genotypes of paired pre- and post-treatment isolates from 8 patients showed an infection with a single strain of H. pylori that had acquired resistance to clarithromycin. In 4 other patients, acquisition of clarithromycin resistance was associated with the presence of different strain types of H. pylori. The remaining 5 patients had clarithromycin-sensitive isolates. Overall, H. pylori from different patients had diverse genotypes, yet most (70%) were colonized by the same predominant and stable strain in both the antrum and corpus. There was no link between the emergence of in vitro clarithromycin resistance and a particular strain genotype for these UK isolates. It was concluded that colonization with a clarithromycin-resistant H. pylori was due to selection of a resistant strain or clonal variant within the infecting population. Present genomic markers had low predictive value for emergence of resistance.

A phase II study of biweekly administration of paclitaxel in patients with recurrent epithelial ovarian cancer

The purpose of this study was to assess the efficacy and toxicity of single agent paclitaxel administered biweekly to patients with relapse of epithelial ovarian cancer previously treated with platinum-based regimen. Forty patients received an initial paclitaxel dose of 134 mg/m2 administered intravenously over three hours every two weeks. 283 cycles were given. All 40 patients were evaluable for toxicity, which mainly consisted of granulocytopenia, myalgia/arthralgia, and peripheral neuropathy. Two patients developed severe hypersensitivity reactions. Dose escalation was possible by one level in 11 patients and by two levels in 12 patients, dose reductions were not necessary. Thirty-five patients were evaluated for response. Five obtained complete response (14%), eight obtained partial response (23%), and nine had stable disease (26%), while 11 patients showed progression (31%). The overall response rate was 37% (95% confidence interval 22-57%). The median duration of responses (complete and partial) was six months. Overall median time to progression and overall median survival for eligible patients (n = 35) was 4.3 months and 11 months, respectively. We conclude that biweekly administration of paclitaxel in recurrent epithelial ovarian carcinoma was active with manageable toxicity.

Noninsulinoma pancreatogenous hypoglycemia: a novel syndrome of hyperinsulinemic hypoglycemia in adults independent of mutations in Kir6.2 and SUR1 genes

In adults, endogenous hyperinsulinemic hypoglycemia is almost invariably due to insulinoma. In these patients with insulinoma, neuroglycopenic episodes exclusively after meal ingestion and negative 72-h fasts are extraordinarily rare. We describe five adults with neuroglycopenic episodes from hyperinsulinemic hypoglycemia within 4 h of meal ingestion and negative 72-h fasts. Each had negative transabdominal ultrasonography, spiral computed tomographic scanning, and celiac axis angiography of the pancreas. However, all showed positive selective arterial calcium stimulation tests indicative of pancreatic beta-cell hyperfunction. At pancreatic exploration, no insulinoma was detected by intraoperative ultrasonography and complete mobilization and palpation of the pancreas. Moreover, the resected pancreata showed islet hypertrophy and nesidioblastosis, but no insulinoma. No definite disease-causing mutation was detected in Kir6.2 and SUR1 genes, which encode the subunits of the pancreatic ATP-sensitive potassium channel responsible for glucose-induced insulin secretion. Four patients who underwent gradient-guided partial pancreatectomy have been free of hypoglycemic symptoms for up to 3 yr follow-up; the other, who underwent a limited distal pancreatectomy, has had brief recurrence of symptoms. The unique clinical features and responses to dynamic testing in these adults with hyperinsulinemic hypoglycemia in the absence of insulinoma may constitute a new syndrome of postprandial hypoglycemia from diffuse beta-cell hyperfunction.

Inhibition of inducible nitric oxide synthase exacerbates chronic cerebral toxoplasmosis in Toxoplasma gondii-susceptible C57BL/6 mice but does not reactivate the latent disease in T. gondii-resistant BALB/c mice

Infection of C57BL/6 mice with Toxoplasma gondii leads to progressive and ultimately fatal chronic Toxoplasma encephalitis (TE). Genetic deletion or inhibition of inducible nitric oxide synthase (iNOS) from the beginning of infection increased the number of T. gondii cysts in the brain and markedly reduced the time-to-death in this mouse strain. In the present study, we addressed whether iNOS also contributes to the control of intracerebral parasites in a clinically stable latent infection that develops in T. gondii-resistant BALB/c mice after resolution of the acute phase of TE. iNOS was expressed in the inflammatory cerebral infiltrates of latently infected BALB/c mice, but the number of iNOS+ cells was significantly lower than in the brains of chronically infected T. gondii-susceptible C57BL/6 mice. In BALB/c mice with latent TE (> 30 days of infection), treatment with the iNOS inhibitors L-N6-iminoethyl-lysine or L-nitroarginine-methylester for < or = 40 days did not result in an increase of the intracerebral parasitic load and a reactivation of the disease, despite the presence of iNOS-suppressive inhibitor levels in the brain. However, L-nitroarginine-methylester treatment had remarkably toxic effects and induced a severe wasting syndrome with high mortality. In contrast to BALB/c mice, L-N6-iminoethyl-lysine treatment rapidly exacerbated the already established chronic TE of C57BL/6 mice. Thus, the containment of latent toxoplasms in T. gondii-resistant BALB/c mice is independent of iNOS, whereas the temporary control of intracerebral parasites in T. gondii-susceptible C57BL/6 mice with chronic TE requires iNOS activity.

Physical association between recombinant cardiac ATP-sensitive K+ channel subunits Kir6.2 and SUR2A

The inwardly-rectifying K+ channel Kir6.2 serves as a common pore-forming core in various ATP-sensitive K+ (KATP) channels, and it is through assembly with sulfonylurea-receptor (SUR) isoforms, which are ATP-binding cassette (ABC) proteins, that tissue-specific channel phenotypes can be generated. In this regard, Kir6.2 has been shown to physically associate with SUR1 to form the pancreatic KATP channel. While cardiac KATP channel activity can be reconstituted by coexpression of Kir6.2 with a distinct SUR isoform, SUR2A, no direct proof has been provided for physical association between these two proteins. Therefore, we tested, by a coimmunoprecipitation procedure in conjunction with an amino-terminal Kir6.2-antibody, physical association between recombinant Kir6.2 and SUR2A. From a mixture of Kir6.2 and SUR2A in vitro-translated proteins, the Kir6.2-specific antibody coimmunoprecipitated 38-kDa and 140-kDa proteins corresponding to Kir6.2 and SUR2A, respectively. In the absence of Kir6.2, SUR2A was not precipitated by the anti-Kir6.2 antibody, indicating that the antibody recognized SUR2A only when SUR2A formed a complex with Kir6.2. A Kir6.2 deletion mutant lacking 37 amino acids from the carboxyterminus still coimmunoprecipitated with SUR2A, indicating that the distal carboxy-terminus of Kir6.2 is unnecessary for subunit association. Kir6.2 mutants lacking more proximal carboxy-terminus regions, including the M2 transmembrane domain, failed to immunoprecipitate SUR2A, suggesting that the proximal carboxyterminus together with the M2 domain are required for channel assembly. These deletion constructs supported cellular distribution of Kir6.2. Thus, the present study provides direct evidence for physical association between Kir6.2 and SUR2A, essentially reconstituting the cardiac KATP channel in vitro. The demonstration of complex formation between Kir6.2 and SUR2A indicates that the structural basis for channel function may rely on direct physical interaction of the two subunits.

Recombinant cardiac ATP-sensitive K+ channel subunits confer resistance to chemical hypoxia-reoxygenation injury

BACKGROUND

Opening of cardiac ATP-sensitive K+ (KATP) channels has emerged as a promising but still controversial cardioprotective mechanism. Defining KATP channel function at the level of recombinant channel proteins is a necessary step toward further evaluation of the cardioprotective significance of this ion conductance.

METHODS AND RESULTS

KATP channel deficient COS-7 cells were found to be vulnerable to chemical hypoxia-reoxygenation injury that induced significant cytosolic Ca2+ loading (from 97+/-3 to 236+/-11 nmol/L). In these cells, the potassium channel opener pinacidil (10 micromol/L) did not prevent Ca2+ loading (from 96+/-3 nmol/L before to 233+/-12 nmol/L after reoxygenation) or evoked membrane current. Cotransfection with Kir6.2/SUR2A genes, which encode cardiac KATP channel subunits, resulted in a cellular phenotype that, in the presence of pinacidil (10 micromol/L), expressed K+ current and gained resistance to hypoxia-reoxygenation (Ca2+ concentration from 99+/-7 to 127+/-11 nmol/L; P>0.05). Both properties were abolished by the KATP channel blocker glyburide (1 micromol/L). In COS-7 cells transfected with individual channel subunits Kir6.2 or SUR2A, which alone do not form functional cardiac KATP channels, pinacidil did not protect against hypoxia-reoxygenation.

CONCLUSIONS

The fact that transfer of cardiac KATP channel subunits protected natively KATP channel deficient cells provides direct evidence that the cardiac KATP channel protein complex harbors intrinsic cytoprotective properties. These findings validate the concept that targeting cardiac KATP channels should be considered a valuable approach to protect the myocardium against injury.

Subtyping of Campylobacter jejuni Penner serotypes 9, 38 and 63 from human infections, animals and water by pulsed field gel electrophoresis and flagellin gene analysis

Pulsed field gel electrophoresis and PCR-RFLP flagellin gene profiling were used to discriminate 44 isolates of Campylobacter jejuni Penner heat stable (HS) serotypes 9, 38 and 63 from sporadic human infections and other sources. Genomic similarities between HS9 and HS38 strains were demonstrated. HS63 and HS1 strains of Camp. jejuni ssp. jejuni were similar but were genomically distinct from Camp. jejuni ssp. doylei HS63. The molecular analyses provided a basis for assessing associations between cross-agglutinating strains of Camp. jejuni and for subtyping within those serogroups.

Evidence for direct physical association between a K+ channel (Kir6.2) and an ATP-binding cassette protein (SUR1) which affects cellular distribution and kinetic behavior of an ATP-sensitive K+ channel

Structurally unique among ion channels, ATP-sensitive K+ (KATP) channels are essential in coupling cellular metabolism with membrane excitability, and their activity can be reconstituted by coexpression of an inwardly rectifying K+ channel, Kir6.2, with an ATP-binding cassette protein, SUR1. To determine if constitutive channel subunits form a physical complex, we developed antibodies to specifically label and immunoprecipitate Kir6.2. From a mixture of Kir6.2 and SUR1 in vitro-translated proteins, and from COS cells transfected with both channel subunits, the Kir6.2-specific antibody coimmunoprecipitated 38- and 140-kDa proteins corresponding to Kir6.2 and SUR1, respectively. Since previous reports suggest that the carboxy-truncated Kir6.2 can form a channel independent of SUR, we deleted 114 nucleotides from the carboxy terminus of the Kir6.2 open reading frame (Kir6.2deltaC37). Kir6.2deltaC37 still coimmunoprecipitated with SUR1, suggesting that the distal carboxy terminus of Kir6.2 is unnecessary for subunit association. Confocal microscopic images of COS cells transfected with Kir6.2 or Kir6.2deltaC37 and labeled with fluorescent antibodies revealed unique honeycomb patterns unlike the diffuse immunostaining observed when cells were cotransfected with Kir6.2-SUR1 or Kir6.2deltaC37-SUR1. Membrane patches excised from COS cells cotransfected with Kir6.2-SUR1 or Kir6.2deltaC37-SUR1 exhibited single-channel activity characteristic of pancreatic KATP channels. Kir6.2deltaC37 alone formed functional channels with single-channel conductance and intraburst kinetic properties similar to those of Kir6.2-SUR1 or Kir6.2deltaC37-SUR1 but with reduced burst duration. This study provides direct evidence that an inwardly rectifying K+ channel and an ATP-binding cassette protein physically associate, which affects the cellular distribution and kinetic behavior of a KATP channel.

Type 1 interferon (IFNalpha/beta) and type 2 nitric oxide synthase regulate the innate immune response to a protozoan parasite

Type 2 nitric oxide synthase (NOS2) is required for the Th1-dependent healing of infections with intracellular microbes, including Leishmania major. Here, we demonstrate the expression and define the function of NOS2 during the innate response to L. major. At day 1 of infection, genetic deletion or functional inactivation of NOS2 abolished the IFNgamma and natural killer cell response, increased the expression of TGFbeta, and caused parasite spreading from the skin and lymph node to the spleen, liver, bone marrow, and lung. Induction of NOS2 was dependent on IFNalpha/beta. Neutralization of IFNalpha/beta mimicked the phenotype of NOS2-/- mice. Thus, IFNalpha/beta and NOS2 are critical regulators of the innate response to L. major.

Lineages within Campylobacter jejuni defined by numerical analysis of pulsed-field gel electrophoretic DNA profiles

Forty-seven Penner heat-stable (HS) serotype reference strains for Campylobacter jejuni and 47 serologically non-typable strains were examined by pulsed field gel electrophoresis (PFGE) DNA restriction analysis. The SmaI and KpnI digest profiles were compared by numerical analysis. Most strains grouped differently in the two analyses but strain lineages were inferred where the two agreed. Genetic relationships between reference strains in the cross-reacting HS4 complex were examined. Three clonal lines were evident and comprised: (i) HS4, HS13 and HS16; (ii) HS50 and HS65; (iii) HS43. The majority of those C. jejuni expressing HS antigens not recognised by currently available antisera had > 50% PFGE DNA digest similarity to one or more Penner scheme reference strain(s) and so did not necessarily represent distinct genetic lineages. PFGE analysis provided a high level of discrimination amongst strains of C. jejuni but overall similarity estimates for defining types must be based on the analysis of more than one restriction pattern.

Application of the Mast resistotyping scheme to Campylobacter jejuni and C. coli

The Mast resistotyping scheme was assessed with 228 strains of Campylobacter jejuni and C. coli from enteric infections in man and from a diverse selection of other sources (livestock, chickens and river water). Most (153 of 158) C. jejuni examined were of the three most common Penner (heat stable, HS) serotypes, HS1, HS2 and HS4 complex. Fourteen resistotypes were identified in the 158 strains of C. jejuni and 16 in the 70 isolates of C. coli. The predominant codes were 00 (44% of C. jejuni; 33% of C. coli) and 40 (21% of both species). The scheme was simple to use but reproducibility and interpretation of sensitivity zones--notably for fluorouracil, triphenyltetrazolium chloride and metronidazole--was occasionally problematic. Overall, resistotypes did not correlate with Penner HS serotypes or with three key genomic markers (ribotype, PFGE macrorestriction-type and fla-type). Although resistotyping offers a rapid means for distinguishing between some strains of C. jejuni and C. coli, discrimination for common resistotypes can be achieved only in combination with other typing methods.

MetR-mediated repression of the glyA gene in Escherichia coli

Inactivation of either of the two MetR binding sites centered at bp -143 and 121 relative to the +1 transcription start site results in reduced glyA-lacZ expression in a wild-type strain below the level seen in a metR mutant. This reduced expression is dependent on the side of the DNA helix MetR binds relative to the RNA polymerase binding site. Thus, a single MetR dimer bound to the DNA may play a physiological role in maintaining appropriate glyA gene expression, functioning as a repressor under low MetR conditions.

RNA polymerase, PurR and MetR interactions at the glyA promoter of Escherichia coli

In Escherichia coli, the MetR and PurR proteins positively and negatively regulate glyA gene expression, respectively. A DNase I footprint analysis showed that both proteins bind independently to the glyA control region. The PurR protein blocks RNA polymerase (RNAP) from binding to the glyA promoter. The presence of hypoxanthine, the co-repressor of PurR, increases the ability of PurR to prevent RNAP binding, providing a model for repression of the glyA gene by PurR. In contrast, MetR alters the RNAP footprint pattern of the glyA control region. In addition, the MetR footprint is increased in the presence of RNAP, suggesting that the two proteins might interact.

Cooperative MetR binding in the Escherichia coli glyA control region

We determined the relative binding affinity of the MetR protein for wild-type and mutant MetR binding sites 1 and 2 in the Escherichia coli glyA control region. The results show that MetR binding site 1 has a higher affinity for the MetR protein than binding site 2. In addition, the results suggest that binding of MetR to the glyA promoter is cooperative. Mutations that decrease the ability of MetR to bind to either site 1 or site 2 have no significant effect on MetR's ability to bend DNA.

Escherichia coli cis- and trans-acting mutations that increase glyA gene expression

We used an Escherichia coli strain blocked in serine biosynthesis and carrying a partial glyA deletion to isolate strains with altered regulation of the glyA gene. The glyA deletion results in 25% of the normal serine hydroxymethyltransferase activity. Three classes of mutants with increased glyA expression were isolated on glycine supplemented plates. One class of mutations increased glyA expression 10-fold by directly altering the -35 consensus sequence of the glyA promoter. The two other classes increased glyA expression about 2- and 6-fold, respectively. The latter two classes of mutations also affected regulation of the metE gene of the folate branch of the methionine pathway, but not metA in the nonfolate branch of the methionine pathway, or the gcv operon, encoding the glycine cleavage enzyme system. The mutations were mapped to about minute 85.5 on the E. coli chromosome.

Characterization of the MetR binding sites for the glyA gene of Escherichia coli

Sequence analysis of the glyA control region of Escherichia coli identified two regions with homology to the consensus binding sequence for MetR, a lysR family regulatory protein. Gel shift assays and DNase I protection assays verified that both sites bind MetR. Homocysteine, a coregulator for MetR, increased MetR binding to the glyA control region. The MetR binding sites were cloned into the pBend2 vector. Although the DNA did not show any significant intrinsic bend, MetR binding resulted in a bending angle of about 33 degrees. MetR-induced bending was independent of homocysteine. To verify that the MetR binding sites play a functional role in glyA expression, site-directed mutagenesis was used to alter the two binding sites in a lambda glyA-lacZ gene fusion phage. Changing the binding sites toward the consensus MetR binding sequence caused an increase in glyA-lacZ expression. Changing either binding site away from the consensus sequence caused a decrease in expression, suggesting that both sites are required for normal glyA regulation.