Determination of Glyphosate and Aminomethylphosphonic Acid in Crops by Capillary Gas Chromatography with Mass-Selective Detection: Collaborative Study

A collaborative study was conducted to validate a method for the determination of glyphosate and aminomethylphosphonic acid (AMPA) in crops. The analytes are extracted from crops with water, and the crude extracts are then subjected to a cation exchange cleanup. The analytes are derivatized by the direct addition of the aqueous extract into a mixture of heptafluorobutanol and trifluoroacetic anhydride. The derivatized analytes are quantitated by capillary gas chromatography with mass-selective detection (MSD). The collaborative study involved 13 laboratories located in 5 countries 12 laboratories returned valid data sets. The crops tested were field corn grain, soya forage, and walnut nutmeat at concentrations of 0.050, 0.40, and 2.0 mg/kg. The study used a split-level pair replication scheme with blindly coded laboratory samples. Twelve materials were analyzed, including 1 control and 3 split-level pairs for each matrix, 1 pair at each nominal concentration. For glyphosate, the mean recovery was 91%, the average intralaboratory variance, the repeatability relative standard deviation (RSDr), was 11%, and the interlaboratory variance, the reproducibility relative standard deviation (RSDR), was 16%. For AMPA, the mean recovery was 87%, the RSDr was 16%, and the RSDR was 25% at mg/kg levels.

Prevalence of HLA-B*57:01 allele in Argentinean HIV-1 infected patients

Hypersensitivity reaction to abacavir (ABC hypersensitivity syndrome, AHS) is strongly associated with the presence of the HLA-B*57:01 allele. This study was designed to estimate the prevalence of HLA-B*57:01 allele in Argentinean HIV-1 infected patients. We analyzed the presence of HLA-B*57:01 allele in 1646 HIV-1 infected patients from different regions of Argentina. This allele was detected in 81 patients; most of them corresponded to patients living in the central region of the country. The prevalence of HLA-B*57:01 was 4.9%, similar to other Caucasian populations and higher than other data reported for South American populations. This strongly supports screening for the presence of HLA-B*57:01 in abacavir treatment of HIV-1 in our country.

Use of cannula ileostomy to protect a low colorectal anastomosis in patients having preoperative neoadjuvant chemoradiotherapy

AIM

This study evaluated the efficacy and safety of ileal diversion, using a tracheal cannula, to protect from a low colorectal anastomosis in patients treated with neoadjuvant chemoradiotherapy.

METHOD

Fifty patients who presented with rectal cancer and who had accepted neoadjuvant chemoradiotherapy were included. All underwent a low anterior resection with ileal diversion by either tracheal cannula ileostomy (n = 28) or conventional loop ileostomy (n = 22). Demographics, clinical features and operation data were recorded.

RESULTS

Two patients developed anastomotic dehiscence after completion of the cannula ileostomy but neither patient required any further operation. There was no difference in anastomotic dehiscence, peritonitis or requirement for further surgery in patients treated with cannula ileostomy and loop ileostomy.

CONCLUSION

Cannula ileostomy is a safe, quick, effective and convenient means of intestinal diversion after low anterior resection. Its obvious advantage over loop ileostomy is a reduced overall hospital stay and avoidance of the need to close the stoma.

HIV mother-to-child transmission: a complex genetic puzzle tackled by Brazil and Argentina research teams

Human immunodeficiency virus (HIV) mother-to-child transmission is a complex event, depending upon environmental factors and is affected by host genetic factors from mother and child, as well as viral genetic elements. The integration of multiple parameters (CD4 cell count, virus load, HIV subtype, and host genetic markers) could account for the susceptibility to HIV infection, a multifactorial trait. The goal of this manuscript is to analyze the immunogenetic factors associated to HIV mother-to-child transmission, trying to unravel the genetic puzzle of HIV mother-to-child transmission and considering the experience in this topic of two research groups from Brazil and Argentina.

Detrimental effects of mannose-binding lectin (MBL2) promoter genotype XA/XA on HIV-1 vertical transmission and AIDS progression

BACKGROUND

The literature on the involvement of mannose-binding lectin (MBL) in human immunodeficiency virus (HIV) transmission and acquired immunodeficiency syndrome (AIDS) is conflicting. Polymorphisms in the MBL2 gene reduce the level of protein and alter its structure. Thus, we investigated whether MBL2 alleles and plasma concentrations of MBL are associated with perinatal HIV transmission and disease progression.

METHODS

Frequencies of MBL2 allelic variants (B, C, D, and X) were estimated among 345 HIV-exposed children and 147 blood donors. AIDS-free time was evaluated for different MBL2 genotypes and MBL plasma levels. The median duration of follow-up was 96.5 months.

RESULTS

In the Argentinean population, gene frequencies of MBL2 variants were 18%, 15%, and 3% for the X, B, and D alleles, respectively, with no identified C allele. The haplotype XA/XA was associated with an 8-fold risk of acquiring HIV-1 (P= .054; odds ratio [OR], 8.11 [95% confidence interval {CI}, 0.96-67.86]) and almost a 3-fold risk of progression to pediatric AIDS (P= .026; OR, 2.81 [95% CI, 1.14-7.47]). We also found an independent positive correlation between the rate of AIDS progression and MBL plasma concentration (P= .008; OR, 1.28 [95% CI, 1.07-1.55]).

CONCLUSIONS

Our results demonstrate that homozygosity for the MBL2 promoter genotype XA/XA is an important genetic determinant of HIV-1 acquisition through vertical transmission and the pathogenesis of pediatric HIV/AIDS, via a mechanism that remains to be established.

Estrogenic status influences nitric oxide-regulated TNF-alpha release from human peripheral blood monocytes

Cytokines and nitric oxide (NO) have been implicated in bone loss caused by estrogen deficiency. Here we evaluated the effect of nitric oxide synthase (NOS) inhibitors on the bone particle resorbing activity and TNF-alpha release of cultured peripheral blood monocytes (PBM) obtained from 10 premenopausal (PreM) and 10 postmenopausal (PostM) women. Gonadal status (menopause < 3 yr) was assessed by FSH and estradiol. Bone alkaline phosphatase and N-Telopeptide were significantly increased in PostM. Significant differences between PreM and PostM women were observed in bone mineral density of lumbar spine. The bone particle resorbing activity of PBM cultured in the presence of L-arginine-methyl ester (NAME) or aminoguanidine, NOS inhibitors, was determined by (45)Ca release from rat bone labeled particles. TNF-alpha release was assayed in supernatants by ELISA. (45)Ca release was higher in PostM (p < 0.01) and was enhanced by NAME (p < 0.02). Furthermore, TNF-alpha release from PBM was significantly higher in PostM (p < 0.01). Aminoguanidine significantly increased TNF-alpha release in PreM. Based on these findings and on the evidence that estrogen stimulates NOS, we suggest that estrogen withdrawal may reduce the inhibitory effect of NO on TNF-alpha release. Thus, this increased production of TNF-alpha could contribute to the increased postmenopausal bone turnover.

Electron and light microscopy of neutrophil responses in mice vaccinated and challenged with third-stage infective hookworm (Ancylostoma caninum) larvae

The role of neutrophils in mediating host inflammation was examined in mice vaccinated with living third-stage infective hookworm larvae (L3). Mice were vaccinated by oral immunization with 500 L3 (Ancylostoma caninum) once every 2 weeks for a total of three immunizations. The vaccinated mice were then challenged intraperitoneally with 2000 L3) 1 week after the final immunization. To stimulate peritoneal production of neutrophils, 2 ml of 2% glycogen were injected intraperitoneally at 16 h prior to the challenge infection. Neutrophils were found to comprise 85% of the peritoneal cell population. L3 from the challenge infection were collected and then examined at timed intervals by inverted light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Greater than a fivefold increase in the total numbers of peritoneal cells was noted in the vaccinated mice as compared to unvaccinated mice. In the peritoneal cavity of vaccinated mice, the neutrophils adhered to the L3 within 2 h, and over 55% of the L3 were surround by clusters of neutrophils to form a sausage-like sheath 4 h later. At 24-72 h after challenge, almost all of the L3 recovered from the vaccinated mice were covered with thick clusters of cells. Both SEM and TEM demonstrated extensive ultrastructural damage to the L3. In contrast, the L3 recovered from the unvaccinated mice appeared to be unaffected by neutrophils. These studies suggest that neutrophils, like macrophages, can have an important role as effector cells in L3-vaccinated mice.

Efficiency, efficacy, and adverse effects of adenovirus vs. liposome-mediated gene therapy in cardiac allografts

Virus- and nonvirus-mediated immunosuppressive cytokine gene therapy prolongs cardiac allograft survival in various nonfunctional heart transplant animal models, but its cardiac adverse effects have not been addressed. Recently, we developed a functional heterotopic heart transplant model in rabbits. For the first time, we were able to systematically compare the efficiency, efficacy, and adverse effects of optimized adenovirus- and liposome-mediated ex vivo interleukin (IL)-10 gene transfer in functional donor hearts. The efficiency of liposome-mediated gene transfer was greatly improved in physiologically functioning donor hearts and was only three- to fourfold lower than adenovirus-mediated gene transfer. The efficacy of liposome-mediated IL-10 gene transfer was much higher than that mediated by adenovirus. Significant negative inotropic and arrhythmogenic adverse effects on transplanted hearts were observed due to viral cytotoxicity and immunogenesis, which greatly abated the therapeutic efficacy of this first generation adenovirus-mediated gene therapy.

Distribution of CCR5-Delta 32 and CCR2-64I alleles in an Argentine Amerindian population

In order to evaluate the frequency distributions of CCR5-Delta 32 and CCR2-64I polymorphisms in an Amerindian population, we tested a total of 42 Chiriguanos individuals that are aboriginal inhabitants of the north west of Argentina. Only one carried the CCR5-Delta 32 allele (0.0238), while 17 out of 35 carried the CCR2-64I mutation, including one homozygous for the mutated allele (0.2571). Although the cohort studied is considered highly endogamic, the HLA genotyping revealed that 8 out of 42 subjects had a gene flow from Caucasian populations. The only heterozygous CCR5+/Delta 32 found and three heterozygous CCR2+/64I belonged to the admix group. In conclusion, the protective deletion CCR5-Delta 32 is practically absent in Chiriguanos whereas the CCR2-64I allele is highly frequent.

Increased incidence of atrial flutter associated with the rejection of heart transplantation

Atrial fibrillation (AF) and atrial flutter (Afl) are common dysrhythmias that occur after orthotopic heart transplantation (OHT); however, their etiology and clinical significance have not been defined. To determine the precise incidence of sustained AF and Afl and their association with cardiac rejection, 892 consecutive patients who underwent OHT were studied. A total of 104 patients had 113 episodes of Afl; 102 patients had 117 episodes of AF. The incidence of Afl (12.7%) was the same as AF (13.1%). Sixty-nine AF episodes occurred in first 2 weeks after transplantation, and 22 of which were associated with rejection. In contrast, only 20 Afl episodes occurred the first 2 weeks after OHT, 10 of which were associated with rejection. Fifty-two episodes of Afl occurred during from the third week to 6 months after transplantation, 34 of which were associated with moderate to severe cellular or humoral rejection and/or transplant coronary artery disease (TCAD). All 41 Afl episodes that occurred 6 months after transplantation were associated with cellular and humoral rejection, and/or TCAD. The prevalence of Afl was significantly higher in biatrial than bicaval anastomosis. Atrial conduction defect, manifested by the increase of terminal force of the P wave in lead V(1) of the surface electrocardiogram, predicted the occurrence of Afl and AF associated with rejection in OHT with a sensitivity of 89% and specificity of 92%. These results demonstrate that the incidence of Afl increased after OHT, which might be a consequence of cellular and humoral rejection, and coronary vasculopathy of the transplanted hearts.

Concordance between the CC chemokine receptor 5 genetic determinants that alter risks of transmission and disease progression in children exposed perinatally to human immunodeficiency virus

If CC chemokine receptor 5 (CCR5)-dependent mechanisms at the time of initial virus exposure are important determinants of virus entry and disease outcome, then the polymorphisms in CCR5 that influence risk of transmission and disease progression should be similar; this hypothesis was tested in a cohort of 649 Argentinean children exposed perinatally to human immunodeficiency virus type 1 (HIV-1). Two lines of evidence support this hypothesis. First, CCR5 haplotype pairs associated with enhanced risk of transmission were the chief predictors of a faster disease course. Second, some of the haplotype pairs associated with altered rates of transmission and disease progression in children were similar to those that we previously found influenced outcome in European American adults. This concordance suggests that CCR5 haplotypes may serve as genetic rheostats that influence events occurring shortly after initial virus exposure, dictating not only virus entry but, by extension, also the extent of early viral replication.

Global survey of genetic variation in CCR5, RANTES, and MIP-1alpha: impact on the epidemiology of the HIV-1 pandemic

Expression of CC chemokine receptor 5 (CCR5), the major coreceptor for HIV-1 cell entry, and its ligands (e.g., RANTES and MIP-1alpha) is widely regarded as central to the pathogenesis of HIV-1 infection. By surveying nearly 3,000 HIV+ and HIV- individuals from worldwide populations for polymorphisms in the genes encoding RANTES, MIP-1alpha, and CCR5, we show that the evolutionary histories of human populations have had a significant impact on the distribution of variation in these genes, and that this may be responsible, in part, for the heterogeneous nature of the epidemiology of the HIV-1 pandemic. The varied distribution of RANTES haplotypes (AC, GC, and AG) associated with population-specific HIV-1 transmission- and disease-modifying effects is a striking example. Homozygosity for the AC haplotype was associated with an increased risk of acquiring HIV-1 as well as accelerated disease progression in European Americans, but not in African Americans. Yet, the prevalence of the ancestral AC haplotype is high in individuals of African origin, but substantially lower in non-Africans. In a Japanese cohort, AG-containing RANTES haplotype pairs were associated with a delay in disease progression; however, we now show that their contribution to HIV-1 pathogenesis and epidemiology in other parts of the world is negligible because the AG haplotype is infrequent in non-Far East Asians. Thus, the varied distribution of RANTES, MIP-1alpha, and CCR5 haplotype pairs and their population-specific phenotypic effects on HIV-1 susceptibility and disease progression results in a complex pattern of biological determinants of HIV-1 epidemiology. These findings have important implications for the design, assessment, and implementation of effective HIV-1 intervention and prevention strategies.

Effects of human tissue plasminogen gene transfer on allograft coronary atherosclerosis

BACKGROUND

Transplant coronary atherosclerosis is a major limiting factor to successful long-term cardiac transplantation. The depletion of tissue plasminogen activator (tPA) in the arteriolar smooth muscle cells has been associated with a higher incidence of accelerated graft atherosclerosis. In vivo overexpression of tPA may inhibit accelerated graft atherosclerosis and improve the long-term results of heart transplantation. We evaluated the feasibility, distribution, and effects of intracoronary transfer of the human tPA (htPA) gene in a rabbit heterotopic cardiac transplant model, using a novel cationic liposome compound designed for improved delivery to vascular endothelium.

METHODS

Human tPA cDNA under the control of the SV40 promoter (100 microg) was complexed with the novel cationic liposome (+/-)-N-(3-aminopropyl)-N,N-dimethyl-2,3-bis(dodecyloxy)-1-propanaminium bromide (GAP: DLRIE) (50 microg), and delivered ex vivo to the donor heart by slow intracoronary infusion. Control hearts received an "empty" liposome preparation. Grafts were then implanted into recipient rabbits in the heterotopic cervical position. For the analysis of gene expression, beating donor hearts were collected at 4 days. To examine the effects of htPA expression on graft atherosclerosis, animals received a 0.5% cholesterol diet for 30 days posttransplant, as well as 10 mg/kg cyclosporine A daily. Beating hearts were collected at 30 days posttransplant and analyzed for the development of transplant atherosclerosis by image analysis.

RESULTS

Northern blot analysis for the htPA messenger RNA (mRNA) transcripts showed significantly higher counts in hearts receiving the htPA gene as compared to controls. The distribution of these transcripts favored the left ventricle (LV) and septal regions over the right ventricle (RV). Scintillation analysis of specimens stained by immunoflourescence showed expression of htPA throughout the perivascular myocardium that was significantly higher in grafts transduced with the htPA gene than in control or native hearts. Expression in the vascular wall was also significantly enhanced. Scintillation counts per x 200 field were 262 +/- 145 in htPA-transduced hearts and 20 +/- 27 in controls (p = 0.001), and mean luminescence was 83.7 +/- 12.5 in htPA-transduced hearts and 62.9 +/- 12.8 in controls (p = 0.01). Intimal hyperplasia was assessed by mean percent luminal stenosis in small- and medium-sized arteries and was 31.12 +/- 23.5% in htPA-transduced hearts and 86.59 +/- 17.5% in control hearts (p < 0.0001). These results demonstrate that expression of the htPA gene can be induced by ex vivo intracoronary gene transfer at the time of allograft preservation. Liposome-mediated delivery of the htPA gene at the time of transplantation results in significant early transgene expression, and significantly inhibits the development of graft coronary atherosclerosis.

[Hyperprolactinemia is a frequent finding in HIV infection but does not correlate with viral burden]

Although many authors have reported the finding of hyperprolactinemia during the course of HIV infection, the circumstances determining the rise of prolactin (PRL) concentrations in serum are poorly understood. To analyze the relationships between serum PRL and other clinical variables in HIV-infected patients, 46 HIV-infected patients and 17 seronegative controls were studied. Serum PRL concentrations were significantly higher in the HIV-infected group (p = 0.022). Furthermore, Serum PRL and serum IgG correlated positively (Rs = 0.42; p = 0.05, Spearman-Rank). On the contrary, serum PRL concentrations did not correlate with the plasmic viral burden (Rs 0.039; p = 0.841), Our data confirm that hyperprolactinemia is a frequent finding during the course of HIV infection, and that serum PRL are independent of viral replication kinetics. Considering that a positive correlation was found between serum PRL and immunoglobulins, it is possible that serum PRL might increase in response to non specific immunological activation, or even in response to immunological activation at the onset of infections.

[Immunological properties of prolactin]

A profound bi-directional interaction exists between the hormone prolactin and the immune system. Even the name "hormone" seems to be inadequate, since prolactin is clearly a growth factor and in fact it functions as an immune co-mitogenic cytokine using autocrine, paracrine and obviously endocrine mechanisms. Prolactin (PRL) stimulates lymphocyte proliferation in response to antigen and mitogens. In addition, prolactin is locally secreted by immune cells, and the pituitary production of prolactin is partially under the control of pro-inflammatory cytokines. These reciprocal influences imply the presence of specific receptors for prolactin in many immune cells, such as lymphocytes and other accessory cells. The PRL-binding to its receptor stimulates the synthesis and secretion of lymphocyte cytokines. In addition, it is a growth factor essential for at least one lymphoid cell line. The PRL-corresponding mRNA has been demonstrated in the cytoplasm of mitogen-stimulated lymphocytes, and the secretion of PRL has been well documented in lymphoid cells. Moreover, PRL acts on NK cells to induce their differentiation to prolactin-activated killer cells (PAK cells) in a dose-dependent way (activation at physiological concentrations, and cytotoxicity inhibition at tenfold higher concentrations). PRL also shows a well known capacity to induce IFN-gamma and IL-2 synthesis, suggesting their participation in the genesis of Th1-responses. These PRL immunological properties strongly support PRL as a cytokine. PRL involvement in both the normal immune response and in many pathological conditions raises important considerations regarding potential diagnostic and therapeutic applications.

Association between high serum prolactin levels and concomitant infections in HIV-infected patients

Although prolactin (PRL) is now recognized as a cytokine and persistent immune activation is a common immunopathogenic feature of the human immunodeficiency virus infection (HIV), the circumstances associated with the onset of hyperprolactinemia during the course of this infection remain controversial. Given that PRL is able to exert not only endocrinologic effects but also immunologic influences, a study was conducted to investigate whether raised serum levels of PRL were more likely to prevail when HIV-infected patients developed concomitant infections. Serum PRL concentrations, as well as immunoglobulin isotypes, plasmatic viral burden, CD3+, CD4+, CD8+, CD19+, and natural killer (NK) cell counts were measured in 46 nonselected HIV-infected patients stratified on the basis of the presence or absence of clinically active concomitant infections. Serum PRL levels were significantly higher in patients presenting secondary infections as compared with the asymptomatic ones, with hyperprolactinemia being detected in 10/18 (55%) and 2/28 (7%) of these patient groups, respectively. Hyperprolactinemia was not related with viral burden, antiretroviral treatment, gender differences, or CD4+ cell counts. CD3+, CD4+, CD8+, and CD19+ cells were significantly lower in the group presenting active infections, whereas comparisons in NK cell counts, immunoglobulin levels and HIV viral burden revealed no differences between groups. These results provide evidence that hyperprolactinemia is more prevalent during the onset of secondary infections, which might have diagnostic and therapeutic consequences.

Epidemiology of human ancylostomiasis among rural villagers in Nanlin County (Zhongzhou Village), Anhui Province, China: II. Seroepidemiological studies of the age relationships of serum antibody levels and infection status

Anti-hookworm antibody serologic responses were measured in residents of an Anhui provincial Chinese village where Ancylostoma duodenale is the predominant hookworm. Antibody responses were measured against either soluble infective third-stage larval (L3) or adult antigens. Immunoglobulins of the IgG class, especially IgG4 correlated with both the prevalence and intensity of A. duodenale hookworm infections. In contrast, there was an inverse correlation with IgM, but no correlation with IgA or IgE. Circulating IgG4 antibody responses might serve as a surrogate marker for active A. duodenale hookworm infection.

Differences in mechanisms of SR dysfunction in ischemic vs. idiopathic dilated cardiomyopathy

We examined 1) contractile properties and the intracellular Ca(2+) concentration ([Ca(2+)](i)) transient in cardiac myocytes and 2) sarcoplasmic reticulum (SR) Ca(2+) uptake and release function in myocardium from patients with end-stage heart failure caused by ischemic (ICM) vs. idiopathic dilated cardiomyopathy (DCM). The amplitude of cell motion was decreased 43 +/- 6% in ICM and 68 +/- 7% in DCM compared with that in normal organ donors (DN). Time to peak of shortening was increased 43 +/- 15% in DCM, but not in ICM. Prolongation of the relaxation time was more predominant in ICM. In DCM the systolic [Ca(2+)](i) was decreased 27 +/- 9% and diastolic [Ca(2+)](i) was increased 36 +/- 11%. In ICM the diastolic [Ca(2+)](i) was increased 59 +/- 12% but the systolic [Ca(2+)](i) was unchanged. A significant decrease of the ATP-dependent SR Ca(2+) uptake rate associated with the reduction of the SR Ca(2+)-ATPase protein level was found in ICM. In contrast, the significant decrease in SR Ca(2+) release rate was distinct in DCM. The large amount of Ca(2+) retained in the SR associated with a significant decrease in the maximum reaction velocity and increase in the Michaelis-Menten constant in the caffeine concentration-response curve suggests a fundamental abnormality in the SR Ca(2+) release channel gating property in DCM. We conclude that potentially important differences exist in the intracellular Ca(2+) homeostasis and excitation-contraction coupling in ICM vs. DCM. The SR Ca(2+) release dysfunction may play an important pathogenetic role in the abnormal Ca(2+) homeostasis in DCM, and the SR Ca(2+) uptake dysfunction may be responsible for the contractile dysfunction in ICM.

Atrial conduction disturbance as an indicator of rejection after cardiac transplantation

BACKGROUND

Abnormalities of the terminal force of the P wave in Lead V1 (ptf-V1) and dispersion of corrected atrial repolarization (Ta-TcD) are believed to represent interatrial conduction defect.

METHODS AND RESULTS

To determine whether atrial conduction disturbance correlates with cardiac allograft rejection, we analyzed 249 twelve-lead-electrocardiograms, echocardiograms, hemodynamic parameters, and endomyocardial biopsys from 137 patients with heart transplantation. Both ptf-V1 and Ta-TcD were significantly increased in patients with severe, moderate, and mild rejection. In 22 patients, significant increases of the ptf-V1 and Ta-TcD were observed before positive histological findings, and significantly correlated with severity of rejection during 5- week to 1-year follow-up. Increase of 0.030 mm x sec in ptf-V1 or 0.040 s1/2 in Ta-TcD indicated cardiac rejection > or =1B with sensitivity of 88 and 83%, specificity of 85 and 77%, respectively.

CONCLUSION

These results suggest that the ptf-V1 and Ta-TcD might be an adjunct to detect rejection and reduce the number of surveillance EMB.

Hookworm burden reductions in BALB/c mice vaccinated with recombinant Ancylostoma secreted proteins (ASPs) from Ancylostoma duodenale, Ancylostoma caninum and Necator americanus

Vaccination of mice with alum-precipitated recombinant Ancylostoma secreted protein-1 from the canine hookworm Ancylostoma caninum (Ac-ASP-1) results in protection against A. caninum larval challenge. Vaccine protection is manifested by host reductions in hookworm burden compared to control mice. The goal of this study was to determine whether ASP antigens cloned and expressed from different hookworm species will cross protect against A. caninum larval challenge. Cross-species protection against A. caninum challenge infections was observed with immunizations using recombinant ASP-1 from the human hookworms Ancylostoma duodenale and Necator americanus. However, the degree of protection was proportional to the extent of amino acid sequence homology between the ASP immunogen used for vaccination and the Ac-ASP-1 produced by the challenge larval strain. Vaccine protection was noted to decrease significantly as amino acid sequence homologies diverged 10% or more. It was also determined that Ac-ASP-2, a molecule cloned from A. caninum having 55% amino acid sequence homology to the C-terminus of Ac-ASP-1, did not elicit vaccine protection. These observations were partly reflected in the titer of antibodies that recognize Ac-ASP-1. The studies reported here will help to design immunogenic peptide vaccines based on the sequence divergence of hookworm ASPs.

Protective effect of CCR2-64I and not of CCR5-delta32 and SDF1-3'A in pediatric HIV-1 infection

The effects of chemokine and chemokine receptor genetic polymorphisms such as stromal derived factor 1 (SDF1-3'A), CCR2-64I, and CCR5-delta32 associated with HIV-1 transmission and/or rate of disease progression in infected study subjects remain highly controversial and have been analyzed primarily only in adults. We have investigated whether these polymorphisms may provide similar beneficial effects in children exposed to HIV-1 perinatally. The prevalence of CCR2-64I allele was significantly increased (p = .03) and the CCR2-64I genotype distribution was not in Hardy-Weinberg equilibrium, among HIV-1-exposed uninfected infants. Moreover, in the HIV-1-infected group, a delay to AIDS progression was observed among carriers of CCR2-64I allele. This is the first report that suggests a protective role of CCR2-64I allele in mother-to-infant HIV-1 transmission and documents a delay in disease progression, after the child has been infected with HIV-1. However, SDFI-3'A and CCR5-delta32 alleles did not modify the rate of HIV-1 transmission or disease progression in HIV-1-infected children.

Experimental approaches to the development of a recombinant hookworm vaccine

Hookworm infection is a major parasitic cause of morbidity in the developing nations of the tropics. Development of a genetically engineered vaccine would be a useful tool in the control of this infection in highly endemic areas. Recombinant polypeptides belonging to the Ancylostoma secreted protein (ASP)-1 family have shown promise for reducing hookworm burdens after larval challenge infections in mice. Typically, these polypeptides are expressed in Escherichia coli and administered as an alum precipitate. Vaccine protection is antibody dependent. It is anticipated that a cocktail of different recombinant hookworm antigens may be required in order to effectively prevent heavy hookworm infections and disease. The progress of this work has been hampered by the absence of both a convenient laboratory animal with which to study hookworm infections resembling human infection, as well as the lack of easy availability of native hookworm antigens. In addition, useful human serologic correlates of antihookworm immunity are still poorly defined.

In acute lymphoblastic leukemia deletion of the tumor suppressor gene P16 is associated with abnormal interferon genes

The putative tumor-suppressor gene p16 was mapped to human chromosome 9p21, close to the interferon alpha cluster. The frequency and association of gene alterations of p16, interferon alpha and interferon beta were investigated in a total of 39 Acute Lymphoblastic Leukemia (ALL) patients. Of these, 10 patients (25.6%) presented abnormalities of at least one of the three genes studied. In 32 ALL cases studies of the three genes could be accomplished. In 23 out of 32 ALL cases the 3 genes studied were normally preserved. In the remaining 9 ALL, p16 was affected in 8 cases by homozygous deletions. In 2 patients, p16 deletion was associated with homozygous deletions for interferon alpha and interferon beta genes and in 1 case with total deletion of interferon beta 1 gene and partial deletion of interferon alpha. In the remaining 5 cases, p16 was the only gene deleted with no alteration of type I interferon genes. These data indicate that p16 gene is deleted in a higher frequency than type I interferon genes in ALL. Moreover, within the ALL group with p16 gene deletion, 37.5% are associated with interferon deletions and in general, ALL with alpha and/or beta interferon gene deletions are associated with p16 deletions. Therefore, p16 gene deletion with preserved type I interferon genes in some ALL suggests that the absence of this cdk inhibitor may disturb the normal cell cycle and favor blast transformation.

Electron and light microscopy of peritoneal cellular immune responses in mice vaccinated and challenged with third-stage infective hookworm (Ancylostoma caninum) larvae

The role of peritoneal macrophages in a murine model of immunity to living hookworm third-stage larvae (L3) was investigated. Mice immunized orally with 500 L3 once every 2 weeks for three times were challenged intraperitoneally with 2000 L3 1 week after the final immunization. The challenged larvae were collected from the peritoneal cavity at intervals between 2 and 72 h and then examined by inverted light microscopy, scanning electron microscopy and transmission electron microscopy. Peritoneal cellular responses in non-immunized mice served as negative controls. The numbers of peritoneal macrophages in immunized mice were 6-7-fold higher than in non-immunized mice. In the peritoneal cavity of immunized mice, host macrophages adhered to the challenged L3 within 2 h and created a cocoon-like encasing which surrounded the parasite. Extensive damage to the L3 was observed which included swelling, collapse and deformation of the larval cuticle. Lysis and vacuolization of the parasite's internal structures were also observed. In contrast, no significant cellular adherence and damage were observed in L3 recovered from non-immunized mice. L3-specific antibody levels were also elevated in the peritoneum of immunized mice relative to non-immunized controls. These studies implicate macrophages as important effector cells in hookworm larval vaccine immunity.

Reliability of laboratory markers of HIV-1 infection in Argentinian infants at risk of perinatal infection

Early and accurate diagnosis of HIV-1 infection in infants born to HIV-1-seropositive mothers is of great importance. Polymerase chain reaction (PCR), HIV culture, and p24 antigen detection assays were evaluated for their ability to detect the presence of HIV in 195 infants at risk of perinatal infection. Using the Centers for Disease Control and Prevention guidelines for assessing HIV infection status in children younger than 18 months, 70 infants (36%) were diagnosed as HIV-1 infected and 125 (64%) lacked virologic and clinical evidence of infection. PCR and HIV culture were the most sensitive laboratory markers, detecting 100% and 98% of positive samples, respectively, regardless of age at testing. HIV-1 p24 antigen assay was detected in 26 of 38 positive samples but not in negative samples. PCR was performed with three different sets of primers (SK38/SK39-SK19-gag, SK68/SK69-SK70-env, and SK150/SK431-SK102-gag). The sensitivity/specificity of the individual assays were for SK19, 96.1%/94.25%; SK70, 89.6%/100%; and SK102, 100%/100%. A sample was considered HIV-1 positive when two positive PCR results were obtained with two different pairs of primers, and negative if the sample was negative when three sets of primers were used. False-positive results were occasionally obtained with probe SK19 in six seroreverter infants before serologic status was known. This suggested that the infection was caused by nonreplicative strains or were false-positive results probably by nonspecific amplification due to cross-reaction with other microorganisms; contamination was discarded because there was no specific amplification with the other two primers. All the HIV-1-infected infants were correctly identified with PCR; all except one could be identified with coculture and only 68.4% were confirmed with p24 antigen assay. No seroreverter infant was misdiagnosed using the criteria selected.

Different Effects of Amiodarone and Quinidine on the Homogeneity of Myocardial Refractoriness in Patients With Intraventricular Conduction Delay

BACKGROUND: Increases in QT and JT dispersion have been suggested as indicative of a proarrhythmic potential as a result of heterogeneity in myocardial refractoriness, the reduction of which by antiarrhythmic agents might be associated with a beneficial effect on the development of serious ventricular arrhythmias. METHODS: To test the hypothesis that amiodarone reduces the heter-ogeneity of ventricular refractoriness to a significantly greater extent than quinidine in patients with intraventricular conduction defects under treatment for ventricular arrhythmias, the corrected and uncorrected QT and JT intervals and dispersions from 12-lead surface electrocardiograms were determined in 120 patients with intraventricular conduction defects with cardiac arrhythmias before and during treatment with amiodarone (n = 60) and quinidine (n = 60). RESULTS: Amiodarone increased QT from 403 +/- 50 ms to 459 +/- 47 ms (P <.001), with a similar increase in the corrected QT interval (QTc) (P <.001). Amiodarone reduced QT dispersion by 40% (P <.001), whereas quinidine increased by 18% (P <.001). The net effects of both drugs were similar for OTc. Amiodarone, but not quinidine, reduced heart rate significantly; amiodarone had no effect on the QRS; but quinidine increased if (P <.001). Quinidine as well as amiodarone increased the JT and JTc intervals significantly, but the effect of quinidine was qualitatively less striking. Amiodarone decreased the JT dispersion by 33% (P <.001) and JTc dispersion by 37% (P <.001). On the other hand, quinidine increased the corresponding values for JT and JTc by 18% (P <.001) and 21% (P <.001), respectively. The overall data on QT and JT dispersion indicate an improvement in the homogeneity of myocardial refractoriness with amiodarone treatment and the converse with quinidine treatment; this observation is consistent with a lower proarrhythmic propensity and mortality with amiodarone than with quinidine. Quinidine increased the QRS interval more than amiodarone, and the data indicate that in patients with intraventricular conduction defects, the monitoring of the JT interval might more accurately reflect changes in myocardial repolarization. CONCLUSIONS: Amiodarone and quinidine both increased the corrected and uncorrected QT and JT intervals; amiodarone decreased and quinidine increased the dispersion of these intervals, and these results suggested an improvement in the homogeneity of myocardial refractoriness as a result of amiodarone treatment and the converse as a result of quinidine treatment. Quinidine increased the QTS interval more than amiodarone, and the data indicate that in patients with intraventricular conduction defects, the monitoring of the JT interval might more accurately reflect changes in myocardial repolarization.

Electrophysiological effects of MS-551, a new class III agent: comparison with dl-sotalol in dogs

MS-551 is a newly synthesized, nonspecific K+ channel blocker. To elucidate its electrophysiological and potential proarrhythmic effects relative to those of dl-sotalol in vivo, serial changes in ECGs, endocardial and epicardial monophasic action potential durations, and left and right ventricular pressures were measured simultaneously in pentobarbital-anesthetized open-chest dogs. Complete heart block was produced by the injection of 37% formaldehyde into the atrioventricular node. Intravenous administration of MS-551 produced prolongation of action potential duration at 90% repolarization time (APD90) immediately after the beginning of infusion and reached plateau at 10 min. MS-551 (1 mg/kg) caused 73 +/- 8% increase in APD90 and 28 +/- 5% increase in QTc at basic cycle length of 700 msec. The maximal prolongation of APD90 induced by 1 mg/kg MS-551 was 39% greater than that by the same dose of sotalol (P < .01). The dose-response curve of prolongation of ventricular effective refractory period produced by MS-551 was shifted significantly to the left compared with that induced by sotalol. The EC50 was 0.5 +/- 0.1 mg/kg and 1.2 +/- 0.2 mg/kg for MS-551 and sotalol, respectively (P < .05). When 0.5 mg/kg MS-551 doses were used, no ventricular arrhythmia was induced by stimulation at 200-msec basic cycle length. When 1.5 mg/kg sotalol was administered, 5 of 15 developed torsade de pointes, 2 of 15 developed ventricular fibrillation and 5 of 15 developed sustained ventricular tachycardia. The idioventricular rates and left ventricular pressures were reduced significantly by sotalol, not by MS-551. In conclusion, MS-551 is a potent class III antiarrhythmic agent that selectively prolongs repolarization in the ventricular myocardium and appears to be devoid of autonomic effects. Dose for dose, it is more potent in prolonging the APD90 and the right ventricular effective refractory period possibly with a lower tendency for the development of proarrhythmia in a canine heart-block model.

Prolactin levels in the cerebrospinal fluid of patients with HIV infection and AIDS

The objective of this study was to assess the levels of prolactin (PRL) in cerebrospinal fluid (CSF) of HIV-infected patients with regard to nonHIV-infected patients, and to assess the levels of prolactin in the CSF of HIV-infected patients with and without neurological HIV-involvement. Seventeen HIV-infected patients with different degrees of immunological and neurological involvement were studied. A second group of six HIV-seronegative patients with varying clinical conditions requiring lumbar punctures were included as controls. CSF was collected from patients and controls. Patients were studied neurologically and neuropsychologically, and computed tomography of the brain were performed. They were staged according to CDC clinical classification for HIV infection, and on the basis of tomographic findings into one of five stages. An additional classification for neurological involvement in AIDS was used. CD4+ cell counts, CSF studies, serum-prolactin levels and CSF-prolactin levels were performed as principal laboratory tests. CSF PRL concentrations were significantly higher in the HIV-infected group (n = 17) than the nonHIV infected control group (n = 6) (mean +/- s.d.; 5.77 +/- 2.22 vs. 3.53 +/- 0.69 x 10(-6) g l-1, respectively; p = 0.009, Mann-Whitney U-test). Moreover, even CSF-PRL concentration was higher in HIV-infected patients without cognitive impairment (stage 0 of the clinical classification), (n = 12) in comparison with nonHIV infected controls (n = 6) (mean +/- s.d.; 5.51 +/- 2.31 vs. 3.53 +/- 0.69 x 10(-1) g l-1, respectively; p = 0.028, Mann-Whitney U-test). There was a good correlation between serum and CSF-PRL levels in HIV-infected patients when measured by the Spearman Rank Test (rs = 0.773; p = 0.005). PRL raised serum levels were found in 4 out of 13 patients (30.73%). We conclude that higher levels of CSF-PRL are more frequently found in HIV-infected patients in comparison to uninfected controls. High levels of circulating PRL were also found in HIV-infected patients corroborating results from other work. A good correlation coefficient was found between circulating and CSF-PRL levels in HIV-infected patients, suggesting that disruption of the blood-brain barrier might account for a possible pathogenic mechanism.

Intracoronary adenovirus-mediated transfer of immunosuppressive cytokine genes prolongs allograft survival

BACKGROUND

Intracoronary transfer and expression of recombinant genes in the intact heart is now feasible. In the transplant setting, local modulation of host immune responses by a genetically modified allograft may offer an attractive alternative to systemic immunosuppression.

METHODS

We tested the efficacy and in vivo effect of intracoronary transfer of two immunosuppressive cytokine genes. First-generation E1-deleted adenoviral vectors expressing the Epstein-Barr virus interleukin-10 (AdSvIL10) or human transforming growth factor--beta 1 (AdCMVTGF-beta) were used. Rabbit cardiac allografts were transduced during cold preservation by slow (1 ml/min) intracoronary infusion of 10(10) pfu/gm diluted viral vectors and then implanted heterotopically. Controls included E1-deleted adenovirus (Ad5dI434) and AdCMVLacZ. Beating allografts were collected on day 4 for analysis of gene transfer efficacy and distribution. Additional grafts were used for evaluation of alloreactivity (n = 34).

RESULTS

Mean allograft viral uptake was 81% (up to 91%). Polymerase chain reactions and reverse transcription-polymerase chain reactions confirmed the presence and expression of both genes in the grafts. beta-Galactosidase staining in AdCMVLacZ-infected grafts demonstrated efficient gene expression, which was highest (100%) in subepicardial regions. More homogeneous transmyocardial distribution of the transgene (in 25% to 40% of cells) could be achieved by pulsatile slow delivery. Allograft survival was 6.9 +/- 0.9 days in controls (n = 12), 11.1 +/- 1.7 days in AdCMVTGF-beta-infected grafts (n = 11, p < 10(-4)), and 11.2 +/- 3 days in AdSvIL10-infected grafts (n = 11, p < 10(-4)). Histologic scores (blinded) showed significantly (p < 0.005) higher regression coefficients for rejection in controls compared with both cytokine-transduced groups. Perioperative administration of cyclosporine A (INN: ciclosporin) to recipients had no effect on survival of AdCMVTGF-beta-infected grafts but reduced survival of AdSvIL10-infected grafts.

CONCLUSIONS

Intracoronary gene transfer of immunosuppressive cytokines to cardiac allografts is efficient and effectively prolongs graft survival. Vectors that would induce long-term expression of such genes may make this approach clinically applicable.

Monocyte phagolysosomal fusion in children born to human immunodeficiency virus-infected mothers

BACKGROUND

Previously we demonstrated that monocyte phagolysosomal fusion is impaired in chronic HIV infection in adult patients.

METHODS

We studied the phagolysosomal fusion of peripheral blood monocytes from 45 children vertically infected with HIV, 38 noninfected infants born to HIV-positive mothers and 14 children born to HIV-seronegative women, by a cytomorphologic method in which acridine orange is used as a fusion marker.

RESULTS

The mean percentages of phagolysosomal fusion +/-SD were 42 +/- 16.1 for HIV-positive children, 55.3 +/- 15.5 for HIV-negative infants born to HIV-infected mothers and 58.2 +/- 12.7 for normal controls. Monocyte phagolysosomal fusion of HIV-infected children was significantly decreased in comparison to noninfected and normal infants (P < 0.001), while there was no difference between the two latter groups. Phagolysosomal fusion impairment in HIV-infected infants inversely correlated with age (r = -0.4527; P < 0.002) and directly correlated with CD4+ T cell counts (r = 0.393; P = 0.03). Moreover, phagolysosomal fusion strongly correlated with clinical manifestations; this function was significantly impaired in moderately and severely symptomatic HIV-infected children with respect to those who remained asymptomatic or mildly symptomatic (P < 0.05).

CONCLUSIONS

Our results suggest that monocyte function in HIV-infected children progressively deteriorates, closely related to the severity of the clinical symptoms.

Acute effects of thyroid hormone on inward rectifier potassium channel currents in guinea pig ventricular myocytes

Thyroid hormones play an important role in cardiac electrophysiology. However, the regulation of cardiac ionic channels by thyroid hormones is still unclear. To evaluate the acute effect of 3,3',5-triiode-L-thyronine (T3) on inward rectifier potassium channel (IK1) action potentials, whole-cell IK1 currents and steady-state single IK1 currents were recorded in guinea pig ventricular myocytes. Acute exposure of cells to T3 resulted in shortening of the action potential durations. This effect was initiated at 5-15 min and reached a stable plateau at 25 min. The amplitude of steady-state whole-cell IK1 was significantly increased by T3 at 1 nM to 1 microM concentration rage and with ED50 12 nM/liter. T3 (1 microM) increased IK1 by 68 +/- 7% at -40 mV and 52 +/- 9% at -100 mV. Similar effects were observed with triiodothyroacetic acid, an analogue of T3 that does not stimulate DNA transcription. The single IK1 open probability (Po) was increased 7 +/- 1% by 1 nM T3 (n = 9, P < 0.05) and 42 +/- 6% by 1 microM T3 at -40 mV (n = 18, P < 0.0001). However, the channel unit amplitude, time constants of open and fast-closed time were not changed. T3 shortened interburst duration at each membrane potential but did not change the burst behavior. To elucidate detailed mechanism, we assumed a three-state model (C1 <==> C2 <==> O) and calculated each rate constant. T3 significantly increased the rate constant, k+1, for the transition from the C1 to the C2 state at RP -40 mV (2.84 +/- 0.56 to 7.28 +/- 1.23 sec-1, P < 0.01), RP -20 mV (3.63 +/- 0.95 to 10.17 +/- 2.60 sec-1, P < 0.05) and RP (6.73 +/- 1.20 to 21.94 +/- 4.49 sec-1, P < 0.01). However, the other rate constants were not affected. These results demonstrate that T3 enhances IK1 with the increment in Po, which mainly results from shortening of interburst duration without any changes in burst behavior. Hence, the shortening of interburst duration is due to acceleration of the transition from the C1 to the C2 state. The enhanced IK1 by T3 might be one of the causes for shortened action potential duration in hyperthyroidism.