Polyphosphate at the Streptomyces lividans cytoplasmic membrane is enhanced in the presence of the potassium channel KcsA.

The distribution of polyphosphate (polyP) within the cytoplasmic membrane of Streptomyces lividans hyphae or protoplasts has been determined at high spatial resolution by elemental mapping using energy-filtered electron microscopy (EFTEM). The results revealed that polyP was best traceable after its interaction with lead ions followed by their precipitation as lead sulphide. Concomitant studies of the S.lividans wildtype (WT) strain and its co-embedded mutant DeltaK (lacking a functional kcsA gene) were conducted by labelling as the surface matrix of either one was labelled by cationic colloidal thorium dioxide. Within the WT strain, additional polyP was found to accumulate distinctly at the inner face of the cytoplasmic membrane. After removal of the cell wall (within protoplasts), the polyP-derived lead-sulphide (PbS) precipitate formed clusters of fibrillar material extending up to 50 nm into the cytoplasm. This feature was absent in the DeltaK mutant strain. Together the results revealed that the presence of the KcsA channel and the structured polyP coincide.

Long-term survival and interruption of HAART in HIV-related pulmonary hypertension.

Reported here is a case of a patient with pulmonary arterial hypertension related to HIV (PAHRH) in which lipodystrophy necessitated interruption of highly active antiretroviral therapy (HAART) and long-term survival was the outcome. Although previous studies have suggested antiretroviral therapy may benefit patients with this rare complication of HIV infection, no worsening of PAHRH was observed when HAART was interrupted. Clinical and echocardiographic parameters remained stable during 7 months of follow up. In cases in which HAART is associated with relevant toxicity, interruption of HAART in patients with PAHRH can be considered, but should be used only if no alternatives are available. Close follow-up is warranted.

Alveolar echinococcosis of the liver in an adult with human immunodeficiency virus type-1 infection.

We describe a patient with human immunodeficiency virus type-1 (HIV) infection and alveolar echinococcosis (AE) with a focus on two messages. Despite being severely immunocompromised over years the patient exhibited a long-term asymptomatic course of AE. This is in clear contrast to reports describing accelerated courses of AE in immunocompromised patients. The patient had therapeutic mebendazole drug levels with only 1/10 of the normal drug dose. He was co-treated with protease inhibitors for his HIV infection. These drugs are known as strong inhibitors of cytochrome P450 3A4 (CYP3A4)-dependent metabolism. We speculate that benzimidazoles and protease inhibitors interfere at the CYP3A4-level. The first report of co-infection of HIV and accelerated AE was in a young girl with an extremely low CD4 cell count and an abrogated lymphoproliferative responsiveness to parasite antigen stimulation. Since the CD4 cell count in our patient remained in the range of 27-150 cells/microl, we speculate that there was a critical threshold of immunosupression for constraining AE. Initial treatment with albendazole for AE added to the current highly active antiretroviral treatment (HAART), and suppressive toxoplasmosis therapy became complicated by pancytopenia. After full recovery of the bone marrow, mebendazole was introduced with a new HAART and the previously prescribed toxoplasmosis maintenance therapy. Surprisingly, efficient mebendazole levels were achieved with an uncommonly low dose. These observations suggest that the benzimidazoles, albendazole and mebendazole, may interact with protease inhibitors, which are known for their strong inhibition of the CYP3A4.

Estimating progression to cirrhosis in chronic hepatitis C virus infection.

To gain a clearer understanding of the rate of progression to cirrhosis and its determinants in chronic hepatitis C virus (HCV) infection, a systematic review of published epidemiologic studies that incorporated assessment for cirrhosis has been undertaken. Inclusion criteria were more than 20 cases of chronic HCV infection, and information on either age of subjects or duration of infection. Of 145 studies examined, 57 fulfilled the inclusion criteria. Least-squares linear regression was employed to estimate rates of progression to cirrhosis, and to examine for factors associated with more rapid disease progression in 4 broad study categories: 1) liver clinic series (number of studies = 33); 2) posttransfusion cohorts (n = 5); 3) blood donor series (n = 10); and 4) community-based cohorts (n = 9). Estimates of progression to cirrhosis after 20 years of chronic HCV infection were 22% (95% CI, 18%-26%) for liver clinic series, 24% (11%-37%) for posttransfusion cohorts, 4% (1%-7%) for blood donor series, and 7% (4%-10%) for community-based cohorts. Factors that were associated with more rapid disease progression included older age at HCV infection, male gender, and heavy alcohol intake. Even after accounting for these factors, progression estimates were much higher for cross-sectional liver clinic series. Selection biases probably explain the higher estimates of disease progression in this group of studies. Community-based cohort studies are likely to provide a more representative basis for estimating disease progression at a population level. These suggest that for persons who acquire HCV infection in young adulthood, less than 10% are estimated to develop cirrhosis within 20 years.

When power does not corrupt: superior individuation processes among powerful perceivers.

To examine whether powerful people fail to individuate the less powerful, the authors assigned participants to either a high-power or low-power role for a computer E-mail role play. In 3 studies, participants in the high-power role made decisions and determined the outcomes of interactions; low-power role players had no power and relied on high-power targets for outcome decisions. Studies I and 2 found that high-power perceivers better individuated low-power targets. Study 3 demonstrated that high-power role players' superior judgment can be impaired by including a task that directs their responsibility toward organizational rather than interpersonal concerns. In all, results suggest that the effect of power on social judgment may be more complex and multifaceted than has previously been acknowledged.

Bactericidal effect of extracorporeal shock waves on Staphylococcus aureus.

Despite considerable knowledge about the effects of shock waves on eukaryotic soft tissues, no data are available concerning their effect on prokaryotic micro-organisms. In vitro studies on the bactericidal effect of extracorporeal shock waves on staphylococci were performed with energy levels that are standard for the disintegration of calculi. Suspensions containing 10(4)-10(5) cfu of Staphylococcus aureus/ml were sealed in plastic tubes and exposed to shock waves, resulting in a mean decrease of 3.1 log(10). Whereas impulse rates of > or =350 resulted in a decrease of cfu/ml equalling the detection limit, lower numbers of impulses did not result in an appreciable bactericidal effect. The bactericidal effect of extracorporeal shock waves might provide the basis for the development of novel therapeutic strategies for bacterial infections.

[Hepatitis C. Diagnostic and prognostic aspects from the insurance medicine viewpoint]. / Hepatitis C. Diagnostische und prognostische Aspekte aus versicherungsmedizinischer Sicht.

Hepatitis C is a chronic infection with potentially serious long-term effects. An acute clinical presentation is the exception, often the disease is only diagnosed through routine screening (e.g. as a blood donor) or work-up for elevated liver enzymes. The silent course of this disease also makes it difficult to interpret epidemiological studies. Potential biases need to be considered which may lead to underestimation or overestimation of prevalence and incidence data. Special attention is needed in evaluating long-term effects as the studies usually deal with small numbers of HCV positives and their selection may not have been randomised. An assessment of the prognosis is difficult, especially in the absence of a series of liver enzyme measurements and if the viral load is unknown. The wide availability of diagnostic tests harbours a potential for anti-selection. Caution is therefore required when designing underwriting guidelines; only well documented cases should be accepted. A response to therapy (e.g. with interferon), alone, does not prove a good prognosis, rather, the course over a 2-year follow-up may give relevant prognostic information.

[Socio-demographic and life-style factors in a Swiss study of HIV non-progression]. / Soziodemographie und Lebensweise in einer schweizerischen Studie zur HIV-Nonprogression.

OBJECTIVES: The study investigates associations between socio-demographic or lifestyle factors and the progression of HIV. METHODS: We recruited a Swiss cohort (n = 56) of long-term survivors and conducted a cross-sectional study of laboratory data as well as factors concerning socio-demography, life-style, and psychology. On the basis of laboratory results, the cohort was divided into 2 subgroups, non-progressors (n = 31) and slow progressors (n = 25), which were subsequently compared. RESULTS: The comparison of socio-demographic factors showed that non-progressors were younger and had a higher income than slow progressors. Our data do not show an association between lifestyle and disease progression. DISCUSSION: Younger age as a cofactor of non-progression confirms various other studies. The association between income and disease progression, also found in another cohort, cannot be explained by unequal access to therapies since, in accordance with the inclusion criteria, no one in our cohort had received antiretroviral therapies. Further research in this field seems important to determine possible links between socio-economic status and disease progression. The lack of association between disease progression and lifestyle factors such as drug use, physical activity or nutrition is in contrast to a common view of HIV in our study population, but is confirmed by a majority of the research in this field.

Thiamin deficiency in HIV-positive patients: evaluation by erythrocyte transketolase activity and thiamin pyrophosphate effect.

BACKGROUND AND AIMS: The aim of the study was to determine the thiamin status in HIV-positive patients. METHODS: Measurement of erythrocyte transketolase activity (ETK) and thiaminpyrophosphate (TPP) effect in 55 consecutive HIV-positive patients of a specialized outpatient clinic were grouped into five groups according to their CD4 counts. Comparison of results of HIV-positive patients with age-matched control group of 22 healthy subjects. RESULTS: Of the patients, 27% had a pathologically-increased TPP effect, 18% of the patients had pathologically-low ETK. The percentage of pathological values of TPP effect in the patients was significantly higher compared with the control group. There was no statistically significant correlation between pathological thiamin status and stage of the disease, zidovudine therapy or nutritional status of the patients. CONCLUSIONS: Thiamin deficiency in HIV-positive patients was found in a higher percentage than previously reported. Thiamine deficiency is not only present in advanced stages of HIV-infection, but also in clinically asymptomatic patients.

Association of syncytium-inducing phenotype of HIV-1 with CD4 cell count, viral load and sociodemographic characteristics.

OBJECTIVES: To study whether syncytium-inducing (SI)/non-SI (NSI) phenotype of HIV-1 is associated with CD4+ lymphocyte count, plasma HIV RNA level, clinical stage and sociodemographic characteristics in antiretroviral-naive HIV-1-infected patients. DESIGN: Cross-sectional analysis of single centre cohort study data. METHODS: SI/NSI phenotype was determined using a cocultivation assay using patients' peripheral blood mononuclear cells and MT2 cells. Standard procedures were used for CD4+ cell counts and viral load measurements in plasma. Univariate and multivariate analyses of association of CD4+ cell counts, viral load, clinical stage, age, sex and mode of HIV transmission were performed. RESULTS: In univariate analysis, SI phenotype was significantly associated with lower CD4+ cell counts, higher HIV RNA plasma levels, symptomatic HIV disease, male sex and age 32-36 years (middle tercile). In multivariate analysis, only lower CD4+ cell counts were associated with SI phenotype (odds ratio per increase of 100 x 10(6)/l, 0.54; 95% confidence interval, 0.38-0.78). CONCLUSIONS: HIV-1 SI phenotype was associated with lower CD4+ cell counts but not with higher plasma viral load, clinical stage or sociodemographic variables.

Single tube competitive PCR for quantitation of CMV DNA in the blood of HIV+ and solid organ transplant patients.

Cytomegalovirus (CMV) infection is a major cause of morbidity and mortality in transplant and HIV-infected patients. However, CMV can also cause asymptomatic infection. An elevated blood viral load as assessed by various methods appears to be a predictor for symptomatic infections, and can be used to identify patients at the highest risk of developing CMV disease. We developed a single tube competitive quantitative PCR assay for CMV DNA, using as a competitor a plasmid carrying the target sequence for amplification with an internal deletion. The analysis of data from repeated extractions and amplifications of samples showed that the coefficient of variation of the assay was typically less than 20%. Clinical samples from 14 HIV-infected and 13 solid organ transplant patients were analyzed. Widely varying CMV DNA levels were found in leukocytes, with a positive correlation with the measure of infectivity in the leukocytes by quantitative culture on fibroblasts. The highest CMV DNA content in leukocytes was found in two patients with presumptive CMV disease. In HIV patients, the amount of DNA in leukocytes was much larger than in solid organ transplant recipients, when standardized for infectivity. Although based on a very limited number of patients, this observation probably points to a difference in the biology of CMV infection in these two categories of susceptible individuals. CMV DNA was also found in the plasma of some of the patients with a high CMV DNA leukocyte load. The present test should be useful for identifying patients at high risk of developing CMV disease, for monitoring therapeutic efficacy of antiviral regimens and to improve the understanding the pathogenesis of CMV infection.

Toxicity, efficacy, plasma drug concentrations and protease mutations in patients with advanced HIV infection treated with ritonavir plus saquinavir. Swiss HIV Cohort Study.

OBJECTIVE: To assess the safety, efficacy and plasma drug levels of the combination of ritonavir plus saquinavir for the treatment of advanced HIV infection. DESIGN: Multicentre pilot study. PATIENTS: Eighteen protease inhibitor-naive patients, with intolerance or contraindication to reverse transcriptase inhibitors, a median CD4 cell count of 12 x 10(6)/l (range, 1-50 x 10(6)/l), and a median HIV viraemia of 5.25 log10 copies/ml (range, 4.00-6.13 log10 copies/ml). METHODS: Patients received 600 mg twice daily of both ritonavir and saquinavir. Viraemia was measured at baseline and at weeks 5, 9 and 13. Response was defined as a drop of viraemia of more than 1 log10 at week 5. Plasma drug levels were determined after at least 3 weeks of combined treatment: samples were collected before and 1, 2, and 4 h after the morning ingestion of both drugs. The protease gene was sequenced at baseline and under treatment. RESULTS: Among the 16 patients evaluable at week 5, 11 were responders, and among these patients, six remained responders at week 13 (two with undetectable viraemia). Study discontinuations were due to side-effects (n = 4), patient choice (n = 3), protocol violation (n = 1) and death (n = 1). Responders had higher drug levels than non-responders (P < 0.01 for saquinavir, P = 0.04 for ritonavir). In two non-responders, development of multiple new mutations at positions 10, 20, 48, 82, 84 and 90 was observed after 5-13 weeks. CONCLUSION: The response to ritonavir plus saquinavir in advanced HIV infection is unpredictable. A minority of patients respond with disappearance of HIV viraemia. In other patients, rapid cumulative emergence of protease mutations conferring resistance to treatment cannot always be prevented by good compliance and relatively high plasma drug levels.

Sequence of gp41env immunodominant region of HIV type 1 group O from west central Africa.

PIP: HIV-1 group O is endemic in the west central region of Africa, where the frequency of infection is estimated to be 3-10% of all HIV-1-infected individuals. However, international travel and immigration have led to group O cases being identified in France, Germany, Belgium, Spain, and the US. With the exception of an infected French woman, all reported group O-infected individuals originate from or have a connection to west central Africa. Since most immunoassay reagents are based upon HIV-1 group M, many HIV immunoassays have lower sensitivity for the detection of group O infections. Serum samples were collected from patients at hospitals, tuberculosis (TB) clinics, and STD clinics in endemic regions of Cameroon and Equatorial Guinea in a study of the sequence divergence with group O isolate infections. Screening of the 1086 samples using a range of research and commercial immunoassays found 255 to be HIV-1 seropositive. On the basis of differential reactivity in the various immunoassays, 8 individuals were identified as potentially being infected with group O virus, of which 4 were drawn from TB patients. 7 of the group-O samples were then subjected to polymerase chain reaction (PCR) amplification to verify group O infection. The gp41(env) immunodominant region was successfully amplified and sequenced from 4 of the 7 samples, 2 of which were from the TB patients; 4 of 1086 samples were definitely infected with HIV-1 group O.^ieng

Cytomegalovirus retinitis: decreased risk of bilaterality with increased use of systemic treatment. Swiss HIV Cohort Study Group.

Cytomegalovirus (CMV) retinitis may be treated systemically or intravitreally. We reviewed retrospectively patients with CMV retinitis, in order to determine whether systemic treatment was associated with less spread of CMV retinitis from one eye to the other. Of 222 cases, 92 patients had bilateral disease at onset of CMV retinitis, leaving 130 for analysis. Bilaterality occurred in 10 patients during 12,687 days of systemic treatment and in 34 during 14,791 days without systemic treatment (odds ratio [OR] = 2.92; confidence interval [CI], 1.44-5.90). Patients who had received systemic treatment for <50% of the follow-up period had a greater risk of bilaterality (OR = 3.7; CI, 2.79-4.54) than did the more intensively treated patients. CD4 cell levels also contributed to increased risk, but multivariate analysis showed that CD4 cell counts and treatment intensity were independent risk factors. CMV retinitis was more likely to become bilateral in patients who received less intravenous therapy. Local treatment can complete but does not replace systemically administered therapy.

[HIV infection: future perspective for a so-called fatal disease?]. / L'infection VIH: perspectives d'avenir pour une maladie dite fatale?

During the last 18 months, our knowledge and possibilities in the field of HIV infections have progressed in four principal domains: (1) better understanding of the dynamics of HIV infections and in particular of the importance of viral replication during the phase of latency, (2) possibility of measuring the viral charge and its use for diagnosis and to follow treatment, (3) access to very effective new anti-retroviral substances which permit hope of long-term stabilization of the infection, (4) clinical demonstration that combined treatments are superior to monotherapy. While, at the beginning of 1996, only three medications were commercialized, there were eight at the end of that year. This paper describes the implications for daily practice of recent scientific discoveries in the field of HIV infection. The importance of compliance is discussed, as well as that of clinical research.

Incidence and direct medical costs of hospitalizations due to osteoporotic fractures in Switzerland.

The objective of this study was to estimate the annual direct medical costs of hospitalizations due to osteoporotic fractures in Switzerland. Days of hospital stay in 1992 were quantified using the casuistic of the medical statistics department of VESKA (Vereinigung Schweizerischer Krankenhäuser, the Swiss Hospital Association), which covers 43% of all hospital beds of that country. Number and incidence of total hospitalizations due to fractures were calculated by extrapolating to 100% the 43% VESKA-selected sample. To estimate number and incidence of hospitalizations due to osteoporotic fractures, internationally accepted age-specific osteoporosis attribution rates were applied. According to the latter the probability of a fracture being caused by osteoporosis increases with age. Mean length of stay for all fractures was calculated (= total hospital days divided by number of cases). By multiplying these mean lengths of stay by the number of osteoporosis-related fracture cases, the number of bed-days due to osteoporotic fractures was calculated. To compare the direct medical costs of hospitalization due to osteoporosis with those due to other frequent diseases, days of hospital stay caused by chronic obstructive pulmonary disease (COPD), stroke, acute myocardial infarction and breast cancer were estimated using the same methodology. A total estimate of 63,170 (f: 33,596, m: 29,574) hospitalizations due to fractures (and other osteoporosis-related diagnoses) was calculated, thus leading to overall annual incidence rates of hospitalizations for fractures of 950/100,000 women and 877/100,000 men. In women, 548,615 hospital days were found to be caused by osteoporosis, 353,654 days by COPD, 352,062 days by stroke, 200,669 days by breast carcinoma and 131,331 days by myocardial infarction. In men, COPD caused more hospitalization days (537,164) than myocardial infarction (196,793), stroke (180,524) or osteoporosis (152,857). Taking a mean price for a hospital day in Switzerland of 845 Swiss francs, the annual costs of acute hospitalizations due to osteoporosis and its complications were approximately 600 million Swiss francs (f: 464, m: 130 million Swiss francs) in 1992. We conclude that there is enough economic evidence to justify wide-scale interventions against osteoporosis in Switzerland.

Genetic polymorphism of CCR5 gene and HIV disease: the heterozygous (CCR5/delta ccr5) genotype is neither essential nor sufficient for protection against disease progression. Swiss HIV Cohort.

Homozygous (delta ccr5/delta ccr5) and heterozygous (CCR5/delta ccr5) deletions in the beta-chemokine receptor 5 (CCR5) gene, which encodes for the major co-receptor for macrophage-tropic HIV-1 entry, have been implicated in resistance to HIV infection and in protection against disease progression, respectively. The CCR5/delta ccr5 genotype was found more frequently in long-term nonprogressors (LTNP) (31.0%) than in progressors (10.6%, p < 0.0001), in agreement with previous studies. Kaplan-Meier survival analyses showed that a slower progression of disease, i.e. higher proportion of subjects with CD4+ T cell counts > 500/microl (p = 0.0006) and a trend toward a slower progression to AIDS (p = 0.077), was associated with the CCR5/delta ccr5 genotype. However, when LTNP were analyzed separately, no significant differences in CD4+ T cell counts (p = 0.12) and viremia levels (p = 0.65) were observed between the wild-type (69% of LTNP) and the heterozygous (31.0%) genotypes. Therefore, there are other factors which play a major role in determining the status of nonprogression in the majority of LTNP. Furthermore, there was no evidence that the CCR5/delta ccr5 genotype was associated with different rates of disease progression in the group of progressors. Taken together, these results indicate that the CCR5/delta ccr5 genotype is neither essential nor sufficient for protection against the progression of HIV disease.

Clinical and biomechanical aspects of external fixation of the pelvis.

OBJECTIVE: The aim was to evaluate the mechanical stability of several traditional and modern external fixators in unstable pelvic ring disruption. DESIGN: In a laboratory study external and internal fixation techniques were tested in seven fresh and five embalmed human pelves with a disruption of the pubic symphysis and one sacroiliac joint (type C1.2 injury according to the Tile-AO classification). BACKGROUND: Stability provided by external fixation depends upon many factors, with the residual pelvic stability being the most important. METHODS: Simulating a single-leg stance, the load was applied quasi-statically to the acetabulum of the unstable hemipelvis. Device failure was defined as displacement >10 mm either at the symphysis pubis or the sacroiliac joint. RESULTS: The frame with the highest failure load (fresh versus embalmed specimens) was the Egbers configuration with the AO fixator (analysis of variance; P < 0.05). Failure was noted at 114.9 N versus 129.5 N. Augmentation of the Mono-Tube by additional internal posterior osteosynthesis gave the following results: sacral bars 325.4 N versus 217.8 N, plate fixation 294.3 N versus 215.8 N, lag screws 338.4 N versus 215.8 N. Failure loads of hybrid fixation of the Orthofix were as follows: sacral bars 257.9 N versus 213.9 N, plate fixation 333.5 N versus 245.3 N, lag screws 397.3 N versus 280.6 N. The differences between the two fixators were not statistically significant. CONCLUSIONS: No single external frame provided sufficient stability. The addition of a posterior internal fixation significantly increased failure loads and controlled the weight-bearing pelvic elements.

[HIV infection and splenectomy: 3 cases and literature review]. / Infection VIH et splénectomie: trois cas et revue de la littérature.

3 splenectomized patients infected by the human immunodeficiency virus (HIV) are described. They all presented with more than 500 CD4/mm3 but, surprisingly, with a CD4 percentage below 15, positive p24 antigenemia and a CD4/CD8 ratio below 0.24. 2 patients had repeated episodes of oropharyngeal candidiasis while their CD4 counts exceeded 800/mm3. These episodes suggested the presence of a certain degree of immuno-suppression and prompted us to introduce anti-HIV therapy. 2 patients also presented with a pulmonary infection, due to Klebsiella pneumoniae and Haemophilus influenzae respectively. The third patient had septicemia due to Streptococcus pneumoniae type 22, despite vaccination and a CD4 count above 700/mm3. In splenectomized HIV-infected patients the number of CD4 lymphocytes should be interpreted with caution, as this number increases after splenectomy. The CD4 percentage and CD4/CD8 ratio correlated better with the clinical stage of HIV infection and gave more valuable indications as to the degree of immunosuppression. A possible correlation between viremia and the number of CD4 lymphocytes in this subset of patients remains to be established. In HIV-infected patients, infections due to S. pneumoniae, H. influenzae, S. aureus and enteric gram-negative bacteria are frequent. After splenectomy, susceptibility to encapsulated bacteria increases even in HIV-negative patients. Early vaccination against the main strains of S. pneumoniae is essential, as vaccinal response is uncertain in patients with less than 400 CD4/mm3.