High prevalence of undiagnosed anxiety symptoms among HIV-positive individuals on cART: a cross-sectional study

INTRODUCTION

Anxiety disorders are frequent in HIV-infected individuals, can pre-exist or occur during HIV infection. We evaluated with a self-reported questionnaire whether anxiety is related to HIV clinical status and therapeutic success in a cohort of HIV-positive subjects in Sicily.

PATIENTS AND METHODS

We enrolled 251 patients on combination antiretroviral therapy (cART) for at least six months; Self Rating Anxiety State SAS 054 was used to diagnose anxiety and a Z score ≥ 45 points was considered diagnostic.

RESULTS

47% of patients were diagnosed with anxiety. Patients showing symptoms related to anxiety had experienced a high number of therapeutic switches (fourth line or more).

CONCLUSIONS

These data confirm a high prevalence of anxiety symptoms among subjects with HIV infection in Eastern Sicily. Physicians should be aware of the extent of the problem and should be able to adequately manage anxiety in the setting of HIV infection.

[Saccharomyces cerevisiae fungemia associated with multifocal pneumonia in a patient with alcohol-related hepatic cirrhosis]

Saccharomyces cerevisiae is usually considered non-pathogenic and has rarely been reported as a cause of fungemia in immunocompromised patients, especially those admitted to an intensive care unit or those affected by acquired immune deficiency syndrome or under immunosuppressive treatment. In all described cases the use of probiotic yeast has been given as the main risk factor. We report a case of S. cerevisiae sepsis complicated by pneumonia in a patient affected by alcohol-related cirrhosis with no evidence of probiotic drug intake. In this case recovery was obtained after a treatment course with liposomal amphotericin B. S. cerevisiae should be taken into consideration when sepsis lacks to isolate any aetiological agent.

CCR5 and CCR3 expression on T CD3+ lymphocytes from HIV/Leishmania co-infected subjects

CC chemokine receptor 5 (CCR5) and CC chemokine receptor 3 (CCR3) are membrane-bound proteins involved in HIV-1 entry into susceptible cells. All T lymphocyte subsets display CCR5 and CCR3 on their membrane surface. T helper 1 cells are known to express CCR5 but not CCR3, and most of T cells expressing CCR3 are T helper 2. This study aimed to assess the expression of CCR5 and CCR3 on peripheral blood CD3+ T lymphocytes of HIV-Leishmania co-infected individuals. A total of 36 subjects were enrolled; nine had HIV-Leishmania co-infection; nine were HIV-infected without Leishmania, nine had visceral leishmaniasis without HIV co-infection and nine were healthy blood donors. HIV-Leishmania co-infected subjects showed a significantly higher rate of CCR5+CD3+ T lymphocytes in comparison with the other studied groups. The higher rate of CD3+ T-cells expressing CCR5 found in HIV-Leishmania co-infected subjects may be related to the role of Leishmania as an enhancer of the progression to AIDS.

Ribavirin up-regulates IL-12 p40 gene expression and restores IL-12 levels in Leishmania-treated PBMCs

Ribavirin, a nucleoside analogue that interferes with viral mRNA synthesis and inhibits the replication of RNA and DNA viruses, has been recently proposed as an effective immune response modulator. In the present report, we studied the effect of ribavirin on IL-12 p40 gene expression in peripheral blood mononuclear cells (PBMCs) of healthy subjects. We also studied ribavirin effects on PBMCs activated with lipopolysaccharide (LPS) and phytohaemagglutinin (PHA) and treated with Leishmania donovani antigens. We provide evidence that ribavirin was able to up-regulate IL-12 p40 gene expression and to restore levels of IL-12 p40 gene expression and IL-12 secretion in fully activated PBMCs that were strongly inhibited by L. donovani antigens. Because effective management of leishmanial disease is usually associated with a prevalent T-helper 1 immune response with elevated production of IL-12,our preliminary results may be of particular interest, provided that they will be confirmed by further in vitro and in vivo studies, when considering a possible use of ribavirin as adjuvant in severe leishmanial disease.

Clinical survey of Leishmania/HIV co-infection in Catania, Italy: the impact of highly active antiretroviral therapy (HAART)

The clinical and parasitological features of visceral leishmaniasis (VL) were investigated, retrospectively, in 27 HIV-infected patients who attended the out-patient clinic of Catania University's Department of Infectious Diseases between 1990 and 1998. The aim was to evaluate the epidemiological, clinical, therapeutic and prognostic characteristics of the co-infection, to determine if there were any interactions between the two infections, and to see if the use of highly active antiretroviral therapy (HAART) had any impact on the leishmaniasis. The most dramatic observation was a marked, HAART-attributable reduction in the annual incidence of VL relapses among the patients.

Visceral leishmaniasis in those infected with HIV: clinical aspects and other opportunistic infections

Cases of visceral leishmaniasis (VL) in HIV-positive individuals have been reported from most areas of the world where the geographical distributions of the two infections overlap. The majority of the co-infected cases that have been recorded, however, live around the Mediterranean basin. In these subjects, the length of the incubation period of VL is presumably very short, particularly in those who have severe immunodepression. At diagnosis, almost all cases of VL/HIV co-infection have been found to have fewer than 200 CD4+ cells/microl blood, and about 50% meet the AIDS-defining criteria during their first episode of VL. The clinical manifestations of VL in HIV-infected individuals may be similar to those seen in HIV-negative cases; fever, pancytopenia and hepato-splenomegaly, for example, are found in 75% of all the HIV-positive cases. Following the dissemination of the parasites, however, the HIV-positive cases may develop unusual, multi-organ pathology. Almost all the cases of co-infection are very prone to VL relapses, even after carefully managed antileishmanial treatment. The opportunistic infections that are often seen in HIV-positives frequently develop during VL episodes, the signs and symptoms of the leishmaniasis then confusingly overlapping with those of the other infections.

Reduction of serum melatonin levels in HIV-1-infected individuals' parallel disease progression: correlation with serum interleukin-12 levels

BACKGROUND

During the natural history of human immunodeficiency virus type I (HIV-1) infection, an impairment of interleukin-12 (IL-12) production precedes a switch from a T-helper 1 (Th1) to a T-helper 2 (Th2) stage of cellular immunity. Melatonin, the main hormone produced by the pineal gland, seems to promote a Th1 response by increasing the production of IL-12 in vitro. The aim of this study was to measure and correlate serum levels of melatonin and IL-12 in a cohort of HIV-1-infected individuals.

PATIENTS AND METHODS

77 anti-HIV-1-positive subjects were enrolled: 20 were in CDC stage A, 25 in CDC stage B and 32 in CDC stage C. 30 healthy HIV-1-seronegative subjects were recruited as controls. IL-12 and melatonin concentrations were quantitated in serum samples.

RESULTS

Mean levels of serum melatonin were significantly lower in HIV-1-infected individuals in comparison with controls (p < 0.001). Within the HIV-1-seropositive group, mean melatonin and IL-12 concentrations were significantly lower in patients in CDC stage C, as compared with patients in CDC stages B and A (p < 0.01).

CONCLUSION

During the natural history of HIV-1 disease, serum melatonin levels are progressively reduced. This reduction may be related to the impairment of Th1 immunoresponses.

Fatal hepatitis during Epstein-Barr virus reactivation

Fulminant hepatitis by Epstein-Barr virus is a rare event which is predominantly due to primary infection. We report a rare case of fatal hepatic failure due to Epstein-Barr virus reactivation in a 19-year-old boy who was taking oral steroids. Transaminase peak and the fulminant course of the disease began soon after steroid interruption. Epstein-Barr virus reactivation was diagnosed on the basis of past clinical history of heterophile-positive infectious mononucleosis, a high titer of IgG anti Epstein-Barr virocapsidic antigen, slight elevation of anti-virocapsidic IgM, a high titer of anti-EA IgG antibodies and elevated viral load in serum measured by polymerase chain reaction. It is concluded that Epstein-Barr virus should be considered as a possible etiological agent of fulminant hepatitis.

Visceral leishmaniasis and HIV co-infection: a rare case of pulmonary and oral localization

Visceral leishmaniasis (VL) has increased as a complicating infection in subjects with human immunodeficiency virus (HIV) in countries bordering the Mediterranean sea. The clinical course as well as organ involvement of VL are often atypical in HIV positive subjects. In this study a case of VL with pulmonary and oral mucose localisation in a patient with acquired immune deficiency syndrome (AIDS), is reported. These findings, together with the presence of the parasite in the peripheral blood smear, confirm that in HIV positive patients the impaired immune system allows the spreading and the atypical localisation of the Leishmania amastigotes more easily than in immuno-competent individuals. In endemic areas and in HIV positive subjects a systemic and careful parasitological follow-up is necessary to ensure that any clinical form of leishmaniasis is not overlooked.

Mitochondrial DNA sequences in prehistoric human remains from the Alps

The spread of agriculture that started in the Near East about 10 000 years ago caused a dramatic change in the European archaeological record. It is still unclear if that change was caused mostly by movement of people or by cultural transformations. In particular, there is disagreement on what proportion of the current European gene pool is derived either from the pre-agricultural, paleolithic and mesolithic people, or from neolithic farmers immigrating from the south-east. To begin to characterise the mtDNA gene pool of prehistoric Europe we examined five human remains from the Eastern Italian Alps, dated between 14 000 and 3000 years ago. Three of them yielded sufficient amount of mtDNA for analysis. DNA extracts were prepared in two independent laboratories, and PCR products from the first hypervariable segment of the mtDNA control region were cloned and sequenced. Together with the 5200 year old 'ice man', these DNA sequences show that European mtDNA diversity was already high at the beginning of the neolithic period. All the neolithic sequences have been observed in contemporary Europeans, suggesting genealogical continuity between the neolithic and present-day European mtDNA gene pool. The mtDNA sequence from a 14 000 year-old specimen was not observed in any contemporary Europeans, raising the possibility of a lack of continuity between the mesolithic and present-day European gene pools.

Feasibility in needle exchange programme: an evaluation of a pilot programme in Catania, Sicily

INTRODUCTION

Intravenous drug use (10 V) is a primary transmission route for HIV and other blood borne disease. A criminal approach to illicit drug use leads to aggressive attitudes towards drug users and forces them underground, thus hindering their access to Health Service outlets. A 6-month pilot Needle Exchange Programme was set up in Catania, with the aim of reducing the negative effects and consequences of drug use, preventing the spread of blood borne diseases by encouraging the use of clean needles and reduction of needle sharing. To establish contact with the hidden population of the city's, intravenous drug users (IDUs) and promote condom use and safer sex.

METHOD

An equipped camper was parked daily in two of the city's main public squares according to a preset timetable, morning and afternoon. A flexible needle exchange policy, i.e. free clean needles given out regardless of those returned, was adopted as a strategy considered necessary in order to, ensure maximum user-friendliness. Safer shooting information leaflets were given out alongside material for the correct use of the condom and condoms.

RESULT

The number of IDUs, contacted who had previously been referred to a National Health Service Drug Unit (Ser.T.) and not, and number of syringes exchanged were low but increased month by month.

CONCLUSION

Future projects should be undertaken after building up, a collaborative network between Street Unit and local courts; the city police force; social service outlets; hospitals and other health outlets; Ser.T. units and local pharmacies. In the light of our current experience, the one to one strategy instead to the flexible strategy could lead to stricter adherence to harm reduction strategies amongst IDUs.

Large number of replacement polymorphisms in rapidly evolving genes of Drosophila. Implications for genome-wide surveys of DNA polymorphism

We present a survey of nucleotide polymorphism of three novel, rapidly evolving genes in populations of Drosophila melanogaster and D. simulans. Levels of silent polymorphism are comparable to other loci, but the number of replacement polymorphisms is higher than that in most other genes surveyed in D. melanogaster and D. simulans. Tests of neutrality fail to reject neutral evolution with one exception. This concerns a gene located in a region of high recombination rate in D. simulans and in a region of low recombination rate in D. melanogaster, due to an inversion. In the latter case it shows a very low number of polymorphisms, presumably due to selective sweeps in the region. Patterns of nucleotide polymorphism suggest that most substitutions are neutral or nearly neutral and that weak (positive and purifying) selection plays a significant role in the evolution of these genes. At all three loci, purifying selection of slightly deleterious replacement mutations appears to be more efficient in D. simulans than in D. melanogaster, presumably due to different effective population sizes. Our analysis suggests that current knowledge about genome-wide patterns of nucleotide polymorphism is far from complete with respect to the types and range of nucleotide substitutions and that further analysis of differences between local populations will be required to understand the forces more completely. We note that rapidly diverging and nearly neutrally evolving genes cannot be expected only in the genome of Drosophila, but are likely to occur in large numbers also in other organisms and that their function and evolution are little understood so far.

AIDS-associated Kaposi's sarcoma is more aggressive in women: a study of 54 patients

OBJECTIVE

To describe the epidemiologic and clinical features of AIDS-associated Kaposi's sarcoma (KS) in women compared with men.

METHODS

In a retrospective study, within the Italian Cooperative Group on AIDS and Tumors (GICAT), we compared selected characteristics of 54 women and 108 men with AIDS-associated KS, matched by date of KS diagnosis and referral hospital. The chi2 test was used to test differences among proportions; the Kaplan-Meier method to estimate the survival time, and the Cox proportional hazard model was used to assess the role of gender, age, and CD4 cell count on death's risk.

RESULTS

KS occurred at an earlier age (p = .001), was associated with a more severe immunodeficiency (p = .03), more advanced stages of HIV disease (p = .05), and had more aggressive presentation and course in women than in men. At KS diagnosis, women had a significantly increased proportion of visceral disease (p = .009), in particular pulmonary involvement (p = .002) and atypical sites of involvement (p = .008). The number of deaths due to KS was significantly higher (p = .01) in female patients. Both the higher proportion of visceral disease and of KS-related deaths observed in women did not change after adjusting for CD4 cell count and age. Women showed a decreased overall survival compared with men (8.9 and 14.4 months, respectively; p = .07), and the CD4 cell count at diagnosis significantly influenced survival.

CONCLUSIONS

This study suggests that KS is more aggressive and life threatening in female than in male patients. This peculiar clinical behavior may reflect an inherently more aggressive biology of KS in women, possibly mediated by the level of immunodeficiency.

In vitro production of type 1 and type 2 cytokines by peripheral blood mononuclear cells from subjects coinfected with human immunodeficiency virus and Leishmania infantum

To explore the type 1 and type 2 cytokine profile in cases coinfected with human immunodeficiency virus (HIV) and Leishmania infantum, production of interleukin-4 (IL-4), interleukin-10 (IL-10), interferon-gamma (IFN-gamma), and interleukin-2 receptor (IL-2R) was investigated in mitogen-stimulated and unstimulated peripheral blood mononuclear cell cultures from eight HIV/Leishmania coinfected subjects matched with eight anti-HIV-positive subjects with no evidence of Leishmania coinfection. Levels of IL-4 and IL-2R increased significantly from the baseline levels in the peripheral blood mononuclear cell supernatants of HIV/Leishmania coinfected subjects following stimulation with phytohemoagglutin, whereas the postchallenge concentration of IFN-gamma was significantly increased in the HIV-infected group. The levels of IL-4 and IL-10 were significantly higher in the HIV/Leishmania group throughout evaluation. Post-stimulation IFN-gamma production was significantly higher in the HIV-positive group in comparison with that of the HIV-Leishmania coinfected subjects. These observations support the notion that a Th2 cytokine response is present during a Leishmania infection, even among HIV-coinfected individuals.

Microevolutionary divergence pattern of the segmentation gene hunchback in Drosophila

To study the microevolutionary processes shaping the evolution of the segmentation gene hunchback (hb) from Drosophila melanogaster, we cloned and sequenced the gene from 12 isofemale lines representing wild-type populations of D. melanogaster, as well as from the closely related species Drosophila sechellia, Drosophila orena, and Drosophila yakuba. We find a relatively low degree of sequence variation in D. melanogaster (theta = 0.0017), which is, however, consistent with its chromosomal location in a region of low recombination. Tests of neutrality do not reject a neutral-evolution model for the whole region. However, pairwise tests with different subregions indicate that there is a relative excess of polymorphic sites in the leader and the intron. Codon usage pattern analysis shows a particularly biased codon usage in the highly conserved regions, which is in line with the hypothesis that selection on translational accuracy is the driving force behind such a bias. A comparison of the expression pattern of hb in different sibling species of D. melanogaster reveals some regulatory changes in D. yakuba, which could be interpreted as changes in the timing of secondary expression domains.

Mitochondrial lineages in Ladin-speaking communities of the eastern Alps

European mitochondrial alleles cluster into five haplogroups. Haplogroup 2 is rare in general, but represents more than half of the few known sequences among Ladin speakers of the Alps. Here we describe DNA diversity in control region I of the hypervariable D-loop in 43 Ladins, and in 25 Italian speakers. Analysis of these data, and of previously published sequences, confirms a high degree of differentiation among Ladins and their geographical neighbours. This cannot be regarded as a simple effect of isolating factors, geographic or linguistic, as diversity is high within Ladin communities too. Rather, allele genealogies, population trees, and principal component analysis suggest a relationship between Ladin and Near Eastern samples. Two evolutionary hypotheses seem compatible with these findings. The view whereby Ladins could be descended from Palaeolithic inhabitants of the Alps is supported by the identification, in this study, of the probable ancestral haplotype of group 2, never previously observed in central Europe. Alternatively, a comparatively recent, Neolithic immigration of the ancestors of current Ladin speakers seems consistent with recent linguistic theories. In both cases, the number of lineages present, and their extensive diversity, are not compatible with a serious bottleneck in the Ladin population's history.

Serum cytokines as predictors of clinical outcome in AIDS-related intestinal cryptosporidiosis

BACKGROUND

Clinical variability in the natural course of cryptosporidiosis in patients affected by acquired immunodeficiency syndrome has been correlated to the degree of T-cell immunosuppression; however, cryptosporidiosis can occur as a self-limiting disease even in patients with very low T-lymphocyte count.

AIMS

We tested the serum values of a panel of cytokines in AIDS patients with cryptosporidial enteritis in order to evaluate their role in predicting the clinical outcome of the disease.

PATIENTS AND METHODS

Thirty one HIV-positive patients with cryptosporidiosis and a CD4+ count of less than 100/mm3 were studied. Interleukin-2, Interleukin-4, Interleukin-10, Interferon-gamma, Interleukin-12, Tumor Necrosis Factor alpha values were measured in serum at diagnosis.

RESULTS

Interleukin-4 and Interleukin-10 concentration was significantly lower in patients with mild disease whereas serum Interleukin-2 and -12 was higher in this same group. The serum level of Interferon-gamma did not differ in relation to the severity of the disease. Patients with self-limiting diarrhoea showed significantly lower levels of Tumor Necrosis Factor-alpha than subjects who did not show any clinical improvement.

CONCLUSIONS

In our study, it has been shown that cytokine levels in serum may represent early predictive markers both for the severity of symptoms and the clinical outcome of cryptosporidial enteritis in AIDS patients with a low CD4+ count.

Methadone maintenance and hepatitis C virus infection among injecting drug users

Harm reduction strategies for the prevention of transmission of human immunodeficiency virus (HIV) transmission among injecting drug users (IDUs) have been widely implemented in Australia and are seen to have been effective in preventing the spread of HIV. A major strategy has been increasing the availability of and accessibility to methadone maintenance therapy (MMT) programmes. We have reviewed the experience of a major MMT general practice with hepatitis C virus (HCV) infection from 1991 to 1995. Of 1741 individuals tested for HCV antibodies at least once 66.7% were positive. Of 73 IDUs who were initially seronegative and were retested at least once, 19 were subsequently seropositive. Seroconverters to HCV were younger than non-seroconverters, and were more likely to have evidence of previous hepatitis B infection. The overall HCV incidence rate was 22 cases per 100 person-years, and this did not differ between those on MMT programs (continuous or interrupted) between HCV tests and those not on MMT. These findings suggest that the role of MMT in the control of the spread of HCV infection among IDUs needs further assessment, and that control of the current epidemic of HCV infection among IDUs in Australia will be very difficult.

Eosinophilic ileocolitis by Enterobius vermicularis: a description of two rare cases

BACKGROUND

Human enterobiasis is usually mild. Occasionally, however, an "ectopic" disease may occur with a more severe course. Two rare cases of eosinophilic ileocolitis due to Enterobius vermicularis infection are reported here.

CASE REPORTS

Case n degree 1 was 46 years old, presenting with fever and bloody diarrhoea. Blood eosinophilia was present. Stool microscopy demonstrated red blood cells and leukocytes. A 2 mm long worm with bilateral cervical wings was found in wet-mount preparations of faecal samples. The Scotch tape test was positive for Enterobius vermicularis eggs. Colon biopsy specimens showed massive eosinophilic infiltration and a typical pinworm section overlying the infiltrated mucosa. Case n degree 2 was a 24-year-old, anti-HIV negative homosexual, presenting with watery diarrhoea. Tests for malabsorption were negative. Three mm long adult male E. vermicularis were found on stool microscopy. Biopsy specimens from the colon showed eosinophilic infiltration. In both cases a 200 mg/day course of oral mebendazole eliminated the symptoms within 3 days.

CONCLUSIONS

In these two cases the clinical presentation of enterobiasis was atypical. A common finding was the eosinophilic infiltration of bowel mucosa, although it is still uncertain whether the worm per se may induce mast cell degranulation and eosinophil activation. Nevertheless, the possibility of Enterobius vermicularis infection should be considered in the presence of eosinophilic ileocolitis.

High mitochondrial sequence diversity in linguistic isolates of the Alps

Segment I of the control region of mtDNA (360 bases) was sequenced in seven samples, each of 10 individuals inhabiting villages in the eastern Italian Alps (South Tyrol and Trentino). Three linguistic groups, German, Italian, and Ladin, were represented by two samples each; the seventh sample comes from an isolated group of German origin, the Mocheni, who are linguistically distinct and geographically separated from the bulk of the German speakers. Seventy-four polymorphic sites were identified, defining 63 different haplotypes. Mocheni and Ladin speakers tend to form two clusters in the evolutionary trees inferred from sequences. Analysis of molecular variance shows significant differentiation within samples, among them, and among linguistic groups. Genetic differences between the Ladins and the other groups are not much smaller than between Europeans and some Africans; variation is large within groups, as well, with the exception of only the Mocheni. In the evolutionary trees where the four alpine groups are compared with other European populations, Mocheni and especially Ladins appear as clear outliers. Romansch-speaking Swiss, who are linguistically related to Ladins, are not genetically similar to them, for this segment of DNA. Because the time elapsed since colonization of the Alps (< or = 12,000 years) is short in mutational terms, the only model accounting for the observed relationships between mtDNA variation and linguistic identity seems one in which a population ancestral to Ladin speakers was already differentiated long before the Alps were settled and the current linguistic affiliations were established. For the Mocheni, the results are consistent with a simpler episode of allele loss, from an original genetic pool common to the ancestors of the current German speakers.

A molecular phylogeny for the Drosophila melanogaster subgroup and the problem of polymorphism data

Drosophila melanogaster belongs to a closely related group of eight species collectively known as the melanogaster subgroup; all are native to sub-Saharan Africa and islands off the east coast of Africa. The phylogenetic relationships of most species in this subgroup have been well documented; however, the three most closely related species, D. simulans, D. sechellia, and D. mauritiana, have remained problematic from a phylogenetic standpoint as no data set has unambiguously resolved them. We present new DNA sequence data on the nullo and Serendipity-alpha genes and combine them with all available nuclear DNA sequence data; the total data encompass 12 genes and the ITS of rDNA. A methodological problem arose because nine of the genes had information on intraspecific polymorphisms in at least one species. We explored the effect of inclusion/exclusion of polymorphic sites and found that it had very little effect on phylogenetic inferences, due largely to the fact that 82% of polymorphisms are autapomorphies (unique to one species). We have also reanalyzed our previous DNA-DNA hybridization data with a bootstrap procedure. The combined sequence data set and the DNA-DNA hybridization data strongly support the sister status of the two island species, D. sechellia and D. mauritiana. This at least partially resolves what had been a paradox of parallel evolution in these two species.

Comparison of the indirect immunofluorescent antibody test and the direct agglutination test for serodiagnosis of visceral leishmaniasis in HIV-infected subjects

One hundred subjects positive for anti-human immunodeficiency virus (HIV) antibodies were tested for anti-Leishmania antibodies by the indirect immunofluorescent antibody test (IFAT) and the direct agglutination test (DAT). Subjects were subsequently followed for two years to monitor the onset of visceral leishmaniasis. Fifteen subjects were positive for anti-Leishmania antibodies in either one or both tests. Eleven were positive only by IFAT, one only by DAT, and three by both tests. During the two-year follow-up period, nine subjects developed visceral leishmaniasis; of these, six were serologically positive, four by IFAT alone and two by both tests. The results indicate that IFAT and DAT have a similar specificity but that IFAT has a higher sensitivity and a greater diagnostic significance.

Large differences in substitutional pattern and evolutionary rate of 12S ribosomal RNA genes

We demonstrate using Drosophila, periodical cicadas, and hominid primates, that the molecular clock based on animal mitochondrial small-subunit (12S) rRNA genes ticks at significantly different relative rates depending on which taxa and which region of the gene are examined. Drosophila, which are commonly used as model taxa, are evolving in a highly peculiar manner with the majority of sites in the 3' half of the 12S gene apparently invariant. The analogous 3' half of the mitochondrial large-subunit rRNA gene (16S) appears to be similarly constrained. It is surprising that these regions that are already highly constrained in all animals should be even more constrained in Drosophila, especially when the Drosophila mitochondrial genome as a whole does not display a similar rate slowdown. This extreme 12S rate slowdown is not apparent in periodical cicadas or hominid primates and appears to be related to strong structural and functional constraints rather than a depressed mutation rate. Finally, the slow average rate of evolution in the third domain of Drosophila does not imply that the few variable sites lack multiple hits.

Mitochondrial DNA sequence variation across linguistic and geographic boundaries in Italy

A previous investigation demonstrated the existence of extensive allele frequency diversity within an area of northern Italy crossed by a linguistic (dialect) boundary and by the Po River, either of them or both presumably constraining gene flow. We obtained hair samples from 45 school pupils from 9 localities in that area and sequenced a 255-bp segment of the mtDNA D loop. Estimates of the minimum number of migration events from gene genealogies suggest that the linguistic barrier impaired gene flow more than the river did. However, an analysis of molecular variance (AMOVA) showed that most sequence diversity occurs within rather than between populations and that the differences between groups of populations, defined either by linguistic or geographic criteria, do not reach significance. Three areas of rapid genetic variation were identified; their locations suggest that populations of the western part of the study area evolved in relative isolation. Therefore mtDNA sequence variation does not seem to reflect the same processes--drift and presence of dispersal barriers--that led to the observed distributions of nuclear allele frequencies.

Immunological findings in HIV-Leishmania coinfection

It is supposed that Leishmania infection increases human immunodeficiency virus (HIV) replication in seropositive individuals. Two groups of 9 HIV-infected intravenous drug users each, one group with HIV-Leishmania coinfection (as determined by bone marrow microscopy, culture and an immunofluorescent assay, the other with HIV infection alone, but no evidence of Leishmania coinfection were matched for sex, age, time since first diagnosis of HIV infection, number of AIDS-defining diseases, proportion of patients treated with AZT and months of treatment, CD4/CD8 ratio, beta 2-microglobulin level and HIV p24 antigen positivity rate. IL-4, -6, -10 and -12 and IFN-gamma levels were determined by commercial enzyme immunoassays. The HIV-1 RNA copy number was quantified with the nucleic-acid-sequence-based amplification method (NASBA). The differences between the two groups were highly significant for all markers determined except for IL-12 and IFN-gamma. We found a higher viral load in the patients with HIV-Leishmania coinfection compared to the patients with HIV infection alone (p < 0.009). In 6 HIV-positive individuals without Leishmania coinfection, the HIV-1 RNA copy number was below the detection limit of NASBA (i. e. < 400 copies/100 microliters). Plasma levels of IL-4, -6, and -10 were significantly elevated in the coinfected group (p < 0.0001; p < 0.02, and p < 0.005). The results of our study show that the viral load is increased in patients with HIV-Leishmania coinfection in comparison to the controls. This might be partly due to Th2 immune activation, as demonstrated by higher plasma levels of IL-4, -6 and -10 in HIV-Leishmania-coinfected patients than in HIV-infected individuals.

Nuclear background affects frequency dynamics of mitochondrial DNA variants in Drosophila simulans

Transplasmic lines, in which the original mitochondrial DNA (mtDNA) had been completely replaced by the mtDNA of the donor, were constructed to test for selection on mtDNA variants and to investigate the effects of nuclear-cytoplasmic interactions in Drosophila simulans. These lines were used to set up 12 experimental populations putting in competition two mtDNA variants with two different starting frequencies. Population cages were maintained for 20 generations and periodically sampled to monitor haplotype frequencies. Evidence is provided for a complete reversal of the forces acting on the frequency dynamics of the mtDNA variants according to the lines used to establish the population cages. In the cages where the competing lines had both the original nuclear and mtDNA, the siII type mtDNA variant seemed to be favoured but the situation was reversed when this variant was put in a different nuclear background.

Rates of DNA evolution in Drosophila depend on function and developmental stage of expression

DNA-sequence divergence of genes expressed in the embryonic stage was compared with the divergence of genes expressed in adults for 13 species of Drosophila representing various degrees of relatedness. DNA-DNA hybridization experiments were conducted using as tracers complementary DNA (cDNA) reversed transcribed from poly(A)+ mRNA isolated from different developmental stages. The results indicate: (1) cDNA is less diverged than total single-copy DNA; (2) cDNA sequences are not in the rapidly evolving fraction of the single-copy genome of Drosophila; (3) early in evolutionary divergence embryonic messages are about half as diverged as adult messages; sequence data from some of the species compared indicate this is likely due to differences in rates of silent substitutions in genes expressed at different stages of development; and (4) at greater evolutionary distance, the differences in embryonic and adult messages disappear; this could be due to lineage-specific shifts in codon usage.

HCV and HBV infection among multitransfused thalassemics from eastern Sicily

Serum specimens from 152 Sicilian multitransfused thalassemic subjects were tested for antibodies to hepatitis C virus (anti- HCV) and for HBV markers by enzyme linked immunoassay and with reference to anti-HCV, confirmed by recombinant immunoblot assay. A high rate (47%) of subjects was anti-HCV positive. HBsAg was found in 8% of patients and 55% had anti-HBs or anti-HBc antibodies or both. Contrary to HBV infection, anti-HCV seropositivity was related to the number of transfused units. The highest anti-HCV prevalence was observed between 16 and 20 years; 100% of persons older than 50 years had at least one marker of HBV infection. In conclusion, HCV and HBV are widespread among multitransfused thalassemic. Probably in our area, particularly during the pre-HBsAg screening era, several multitransfused patients were infected by HBV more readily than by HCV.

Preliminary investigation on intrafamilial spread of hepatitis C virus (HCV)

To determine the risk of cohabitant HCV infection, we investigated the sera of 101 family members of 53 anti-HCV antibody positive chronic liver disease patients. Altogether 14.8% of the cohabitants were also anti-HCV antibody positive, compared to a prevalence of 1.4% in the general population. These results suggest that hepatitis-C-virus may spread by person-to-person infection.

HCV infection in HBsAg positive chronic liver disease

The prevalence of anti-HCV antibodies was determined for a group of 68 patients with various forms of chronic liver disease. All patients that were anti-HCV positive but did not show signs of HBV replication had severe liver disease. We therefore suggest that HCV may be responsible for liver damage in HBsAg positive subjects when there are no evident signs of HBV replication.

Mitochondrial DNA sequence divergence in the Melanogaster and oriental species subgroups of Drosophila

The nucleotide sequence of a segment of the mitochondrial DNA from three Drosophila species (D. erecta, D. eugracilis, and D. takahashii), belonging to different subgroups of the melanogaster group has been determined. The segment encompasses three complete tRNA genes (tRNAtrp, tRNAcys, and tRNAtyr) and portions of two protein-coding genes: the subunit 2 of the NADH dehydrogenase (ND2) and the subunit 1 of the cytochrome oxidase (COI). Comparisons also involve homologous sequences already known for four other Drosophila species of the melanogaster group. Length differences were confined in the intergenic region where a long stretch of AT repeats was observed in one of the species analyzed. The three tRNA genes exhibit very different evolutionary rates, the most slowly evolving one, tRNAtyr, is adjacent to the 5' end of COI; tRNAs in similar positions have been previously shown to evolve slowly because they are probably involved in transcript processing. Although the rate of synonymous substitutions was very similar between ND2 and COI genes there were strong discrepancies between them in terms of the number of nonsynonymous substitutions. Differences have also been found in G + C content of the genes, which are likely to be linked to different selective pressures. There is a reduction in G + C content in the region where selective constraints are reduced. This suggests the existence of different levels of constraints along the sequenced segment. An overall analysis of the types of substitutions showed a decrease in A + T content during the course of evolution of the species.

The effect of heteroplasmy on cytoplasmic incompatibility in transplasmic lines of Drosophila simulans showing a complete replacement of the mitochondrial DNA

Unidirectional cytoplasmic incompatibility has been observed in crosses between different strains of Drosophila simulans when the males, but not the females, involved in the crosses are infected with intracellular rickettsia-like microorganisms. In contrast to what is known about this system an unexpected partial incompatibility has been observed between two infected strains. Transplasmic lines have been constructed in the laboratory to investigate this phenomenon. The injection of a foreign infected cytoplasm into a strain which apparently shows the same kind of bacterial infection causes an incompatibility in crosses between injected heteroplasmic males, but not injected females, of the same strain. These findings suggest that several crossing types exist within the Drosophila simulans incompatibility system. The complete replacement of the original mitochondrial DNA observed in some of the transplasmic lines made it possible to analyse and exclude any link between incompatibility and mitochondrial genomes.

Is there selection on RFLP differences in mitochondrial DNA?

Experimental populations of Drosophila simulans were established for the purpose of detecting the presence or absence of selection on a restriction fragment length polymorphism in mitochondrial DNA (mtDNA). It was then discovered that the founding strains differed with respect to the Rickettsia-mediated incompatibility system in this species, which is maternally transmitted together with the mtDNA differences. A population model was constructed using the known fitness effects of the incompatibility system, with the result that the population trajectories can be completely explained by the effects of the microorganism with no need to invoke selection on mtDNA. The strong conclusion is that in this case we can rule out the strong selection proposed by MacRae and Anderson to explain the "dramatic mtDNA changes" in their Drosophila pseudoobscura populations. The population theory used for the experiments is discussed in the context of natural populations. Estimated parameters include the possibility that with two populations, one with the organism and one without it, there may be no bias as to which will invade the other, which in turn suggests no global tendency for the infection to spread or decline.

Natural populations of Drosophila simulans show great uniformity of the mitochondrial DNA restriction map

The mitochondrial DNA of 21 Drosophila simulans isofemale lines of different geographic origins was digested with seven restriction endonucleases. All the lines, with one exception for one line and one enzyme, showed the same restriction patterns. The results confirm previous investigations showing great uniformity of the mtDNA genome in D. simulans.

Esterase-6 allozymes: biochemical studies of two common and one rare variant in Drosophila melanogaster

The biochemical properties of three allozymes coded by the Est-6 locus, two common forms (EST-6S and EST-6F) and one rare form (EST-6VF), were studied. The results show the existence of differences in isoelectric point, activity, activation energy, Km, and temperature coefficient among the three variants, especially between the two common forms and the one rare form. The specific activity of the rare enzymatic variant seems to be less affected by temperature variation. The possible significance of these findings in relation to the mechanism of reproduction is briefly discussed.