Willingness to participate in HIV-1 vaccine trials among young Thai men

OBJECTIVES

Willingness to participate in HIV-1 vaccine trials and associated factors were investigated in a sample of 2670 Royal Thai Army conscripted recruits.

METHODS

Self administered questionnaires were used. Data were collected during the final visit of a longitudinal cohort study of HIV-1 epidemiology. Cross sectional analysis of data from this visit was performed.

RESULTS

32% of the respondents reported they would "definitely" join an HIV-1 vaccine trial. Greater willingness was associated with perceived risk of HIV-1 infection and a desire to help Thai society, although tangible incentives and intentions to reduce condom use in a vaccine trial also were associated with increased willingness. Concerns about physical harm and anticipated social pressure from family not to join were the most substantial impediments to willingness. Concerns about "social harm" (for example, participation would give appearance of having AIDS virus, a partner might refuse sex) also appeared to inhibit interest in joining trials and approached significance.

CONCLUSIONS

Willingness to participate was somewhat greater than in other investigations of non-injection drug user (IDU) cohorts in Thailand, with fewer concerns expressed about physical harm. Motivations appear to involve tradeoffs among perceived risk, anticipated social pressure, altruism, and tangible rewards. The absence of significant problems associated with vaccine trials to date, along with the presence of educational interventions in the study may help explain the lower level of concerns here relative to other Thai studies.

HIV-1 suppression during acute scrub-typhus infection

BACKGROUND

In HIV-1-infected individuals, viral load has been reported to rise transiently if an acute infection with another organism occurs. Our study was prompted by the unexpected finding that HIV-1 copy number fell during an acute infection with Orientia tsutsugamushi, the causative agent of scrub typhus.

METHODS

Serial HIV-1 viral load determinations were made in ten Thai adults with scrub typhus, who were not receiving antiretroviral therapy, and in five HIV-1-infected patients who had other infections (four malaria, one leptospirosis), during and after acute infections. Sera from HIV-1-infected patients with scrub typhus and from mice immunised with O. tsutsugamushi were examined for HIV-1-suppressive activity.

FINDINGS

Median viral load 3 days after admission was significantly lower in the scrub-typhus group than in patients with other infections (193% vs 376% of day 28 values, p=0.03). In four O. tsutsugamushi-infected patients HIV-1 RNA copy number fell by three-fold or more compared with day 28 values, and HIV-1 copy numbers were below the assay threshold in two patients with scrub typhus. Five of seven HIV-1 isolates from non-typhus patients with CD4 lymphocytes less than 200 cells/microL were syncytia-inducing variants, whereas all ten isolates from O. tsutsugamushi-infected individuals matched by CD4-cell count were non-syncytia inducing (p=0.03). Sera from an HIV-1-negative patient with scrub typhus had potent HIV-1-suppressive activity in vitro. Sera from typhus-infected mice inhibited HIV-1 syncytia formation and bound by immunofluorescence to HIV-1-infected lymphocytes.

INTERPRETATION

HIV-1-suppressive factors are produced during some scrub-typhus infection and should be investigated further in the search for novel strategies for the treatment and prevention of AIDS.

Selection for drug-resistant nematodes during and following extended exposure to anthelmintic

Five groups of ten 7-month-old Romney lambs were challenged twice-weekly (2 x 3,000) with either Ostertagia circumcincta (Groups 1-3) or Trichostrongylus colubrifornzis (Groups 4 and 5) infective-stage larvae (L3) following administration of controlled release capsules (CRC) containing either albendazole (ABZ-CRC) (Groups 2 and 5) or ivermectin (IVM-CRC) (Group 3). Larval challenge comprised a mixture of equal numbers of drug-susceptible and -resistant L3 (OR/TR:OS/TS) during the 14-week period of drug release. Positive faecal egg counts (FEC) were recorded in each group during this period. Eggs recovered from faeces were used in an egg hatch assay (EHA) utilizing different concentrations of ABZ. O. circumcincta eggs from Groups 2 and 3 had significantly higher LC50 values than Group 1; eggs of T. colubriformis from the ABZ-CRC treated Group 5 had a higher LC50 than control Group 4. Following the exhaustion of drug release, larval challenge was changed to consist of only susceptible parasites and EHA performed wveekly to determine whether LC50 declined, which would indicate dilution or replacement of drench survivors. In those animals challenged with O. circumcincta, LC50 values were still significantly higher in Groups 2 and 3 at week 19 than in the previously untreated Group 1. For T. colubriformis, LC50 values declined steadily following exhaustion of drug release and were not significantly different between Groups 4 and 5 by week 20. This decline in LC50, and corresponding rise in FEC, was largely the result of 3 animals which dominated with high FEC. The remaining 6 animals showed little decline in LC50 or rise in FEC. The results demonstrate the ability of persistent drugs to screen for resistant parasites and establish that the period of selective advantage for drug-resistant parasites of both species is significantly longer than the period of drug release from CRCs.

A comparative study of the impact of HIV infection on natural killer cell number and function in Thais and North Americans

Innate immunity may play a role in preventing HIV infection and progression to AIDS. Most studies of natural killer (NK) cell function have been conducted in populations with different HLA allele frequencies and HIV subtypes than those found in Southeast Asia. NK cell number and function, defined as CD3- cells expressing CD16+/CD56+ and the ability to lyse K562 cells, were enumerated in 42 HIV-seronegative Thais and 20 HIV-seronegative North Americans. The number and percentage of NK cells were similar for both groups, but cytotoxicity function expressed as lytic units (LU20) of NK cells was significantly greater in the Thai subjects compared with the North American subjects (p = 0.004). Comparisons were also conducted between the HIV-seronegative groups and HIV-infected subjects from both Thailand and North America. NK cell number and function were not significantly different between the Thai HIV-seronegative and -seropositive groups. However, the comparison between the North American HIV-seronegative and -seropositive subjects demonstrated profound impairment of NK cell number, percentage, and function (p < 0.001). Matching the Thai and North American HIV-infected subjects on CD4+ cell count revealed higher NK number and function in the Thai subjects (p < 0.001). The study indicates that NK function in both HIV-seronegative and -seropositive Thais is elevated relative to similar groups in North America.

DTH responsiveness of HIV-infected Thai adults

A study was carried out in Thailand to determine the frequency of reactivity to delayed-type hypersensitivity (DTH) skin tests used for the staging of HIV patients in the United States. A four-antigen panel which included tetanus toxoid (1:10), Candida (1:10), mumps and Trichophyton antigens was assessed in 221 adult subjects from across the full immunological spectrum of HIV disease. Complete anergy was found in 38 per cent of 73 subjects with CD4 counts of 0-200 cells/ml and in 6 per cent of 78 subjects with 201-400 cells/ml. Partial anergy (response to 1 of 4 antigens) was found in 26 per cent of the 0-200 cell/ml group and decreased progressively with increasing CD4 cell count. Results suggested that a 3-member recall antigen panel would provide nearly all the clinically useful information gained by the more standard 4-member panel. In conclusion, DTH skin testing was confirmed to provide a method of assessing the integrity of cellular immune function of HIV-infected Thai adults which correlated with disease progression.

A flow cytometric method for measuring neutralization of HIV-1 subtype B and E primary isolates

BACKGROUND

Clinical trials testing candidate human immunodeficiency virus type 1 (HIV-1) vaccines have required the use of HIV neutralization assays to detect responses to specific geographic subtypes of HIV-1. The variability in results seen with current p24 neutralization assay endpoints prompted us to assess the utility of flow cytometry for monitoring the neutralization of HIV-1 primary isolates.

METHODS

A modified neutralization assay was performed using CD8-depleted peripheral blood mononuclear cells (PBMC). The cells were fixed, permeabilized, stained with a directly conjugated HIV-1 p24 monoclonal antibody, and analyzed by flow cytometry. HIV-1 subtype B' and E primary isolates were tested using pooled sera or plasma from subtype B' or E infected patients.

RESULTS

Primary isolate cultures (without neutralizing antibody) showed from 18% to 42% p24(+) cells, depending on the virus. Less than 0.2% p24(+) cells were detected in uninfected cultures. Subtype-specific neutralization of viruses was observed using plasma or serum pools; neutralization ranged from 0% to 99% reduction of infected cells.

CONCLUSIONS

Flow cytometric detection of intracellular HIV-1 p24 can be used as an endpoint assay to assess neutralization of HIV-1 subtypes B' and E primary isolates. This enumerative method has the advantage of identifying intracellular p24 in specific subsets at an early culture timepoint. It also provides an alternative quantitative endpoint for HIV neutralization assays.

Infectious complications in the critically ill patient with cancer

Significant morbidity and mortality may result from infectious complications in patients with neoplastic disease. Clinical oncologists and infectious disease specialists recognize the emergent nature of these infections in the critically ill patient with cancer. It is essential to have an approach to the understanding of these infections and the circumstances in which they occur. Fever and neutropenia, pneumonia, CNS infections, and gastrointestinal infections are all discussed in this review.

Mannosidosis: an unusual cause of a deforming arthropathy

We report on a case of a deforming arthropathy in a young man with a lysosomal storage disorder. A 31-year-old man with a known diagnosis of mannosidosis presented with a painful swollen right elbow. Radiographs of his right elbow showed a disorganised joint with multiple fragments resembling the appearances of a neuropathic joint. This case provides further evidence that a deforming arthropathy may occur as part of the spectrum of skeletal abnormalities seen in mannosidosis.

Diversity of envelope glycoprotein from human immunodeficiency virus type 1 of recent seroconverters in Thailand

The envelope-coding sequence of human immunodeficiency virus type 1 (HIV-1) was determined for 11 Thai seroconverters between 1995 and 1996. On the basis of the env sequences, all subjects were infected with HIV subtype E. Compared with the interpatient protein diversity among HIV-1 Thai reference sequences from 1990 to 1992 (4.4%), the diversity among the 1995-1996 seroconverters was approximately double (9.5%). The tetrapeptide tip of the V3 loop was invariant for 10 of the 11 seroconverters, and identical to that observed in sequences derived from the 1990-1992 group. However, in the V3 region, sequences from 2 of the 11 subjects demonstrated more than 5 amino acid changes relative to the reference strains. This may represent the "aging" of the HIV epidemic seen in other endemic regions. These findings may have substantial implications for vaccine development and evaluation for both HIV antibody and cytotoxic T lymphocyte repertoire recognition.

Human immunodeficiency virus type 1 test results in patients with malaria and dengue infections

Six rapid enzyme immunoassays for the detection of HIV antibody were performed on paired sera from 66 patients with malaria and 9 patients with dengue. Kit specificities ranged from 77% to 100%, demonstrating that more data are needed on cross-reactivity with endemic diseases as the use of rapid HIV tests increases.

Role of transposon Tn5482 in the epidemiology of vancomycin-resistant Enterococcus faecium in the pediatric oncology unit of a New York City Hospital

During a 36-month period between 1993 and 1995 in the Pediatric Oncology Unit of Memorial Sloan Kettering Cancer Center, 74 patients experienced episodes of infection or colonization caused by vancomycin-resistant enterococci (VRE). Characterization of the 74 bacterial isolates by microbiological and molecular techniques (pulsed-field gel electrophoresis and hybridization with DNA probes specific for the vanA and vanB genes and for IS1251) identified 73 Enterococcusfaecium and one Enterococcusfaecalis (vanB) among the primary VRE isolates. Most (69/73) of the E. faecium isolates carried vanA and four isolates, the vanB gene complex. The overwhelming majority (67/69) of the vanA -positive isolates also gave hybridization signal for IS1251, indicating the presence of the newly described conjugative transposon Tn5482. No hybridization with IS1251 was obtained with the four vanB-carrying isolates. About 30% of the vanA-positive strains (23/69) were represented by PFGE subtype variants of a single clone, most isolates of which were recovered during a 4-month period between April to June of 1994. The larger portion of the vanA-carrying VRE represented by close to 70% of the isolates (46/69) belonged to as many as 37 different clonal types, indicating tremendous genetic diversity. Among 67 of the 69 vanA-carrying isolates, the localization of the Tn5482-associated vanA gene complex could be unequivocally identified either on the chromosome (40/69) or in plasmids (27/69). Transconjugants recovered from filter mating experiments using either a chromosomally located or plasmid-borne vanA donor strain and a single vancomycin-susceptible strain of either E. faecium or E. faecalis were analyzed by molecular typing techniques. Seven out of 10 independent transconjugants recovered from the same cross showed extensive differences in PFGE pattern and also in the localization of the vanA hybridizing DNA fragment transferred from the common VRE donor with chromosomally located vanA. The observations suggest that the extensive genetic diversity observed among the clinical isolates of VRE may be generated during conjugation between vancomycin-resistant and -susceptible enterococcal isolates. The observations also suggest that the epidemic spread of VRE in the United States may be linked to the frequent presence of Tn5482 among the American isolates.

A phase I/II trial of HIV SF2 gp120/MF59 vaccine in seronegative thais.AFRIMS-RIHES Vaccine Evaluation Group. Armed Forces Research Institute of Medical Sciences and the Research Institute for Health Sciences

Fifty-two human immunodeficiency virus type 1, seronegative Thai adults from the community were enrolled in a double-blind, placebo controlled, phase I/II trial of HIV SF2 gp120/MF59 vaccine to determine the safety and immunogenicity of this recombinant, B clade, HIV envelope protein vaccine. Twenty-six subjects were enrolled at each of two sites in Thailand, Bangkok and Chiang Mai. Twelve subjects received placebo and 40 subjects received vaccine (50 microg). Subjects were immunized according to one of two schedules, 0, 1 and 4 or 0, 1 and 6 months. The frequency of adverse reactions was not different between placebo and vaccine subjects, nor between immunization schedules. Of vaccinees, all developed high-titer binding antibody to the immunogen (rgp120), 39 developed neutralizing antibody (NA) responses against homologous virus (HIV-1(SF2)), and 22 developed NA against heterologous virus (HIV-1(MN)). No subject demonstrated intercurrent HIV infection, however screening EIA reactivity occurred in 27% of recipients. Thus, this candidate HIV vaccine was found to be safe and immunogenic in Thai adults, laying the foundation for development of a subtype E construct in this population.

Sensitization to Aspergillus species in the congenital neutrophil disorders chronic granulomatous disease and hyper-IgE syndrome

BACKGROUND

Hyper-IgE syndrome (HIE) and chronic granulomatous disease (CGD) are congenital immunodeficiency diseases with increased susceptibility to bacterial and fungal infections. Both carry significant morbidity and mortality rates because of invasive infections by Aspergillus species. We encountered 2 patients, one with HIE and one with CGD, in whom detection of sensitization to Aspergillus species preceded the diagnosis of immunodeficiency. With high-dose systemic corticosteroids for allergic bronchopulmonary aspergillosis (ABPA), an inflammatory disorder caused by sensitization to Aspergillus species, pulmonary abscesses developed in the patient with HIE, and the patient with CGD succumbed to an overwhelming Aspergillus species-induced pneumonia.

OBJECTIVE

We sought to assess the prevalence of sensitization to Aspergillus fumigatus and the presence of diagnostic criteria for ABPA in patients with CGD and HIE.

METHODS

We measured A fumigatus-specific serum IgE, IgG, and precipitating antibodies as indicators for A fumigatus sensitization in the sera of 18 patients with neutrophil disorders (7 with HIE and 11 with CGD). Hospital records were reviewed for the presence of other diagnostic criteria for ABPA (asthma, elevated total serum IgE concentration, and radiographic abnormalities).

RESULTS

Twelve (67%) of 18 patients were sensitized to A fumigatus, as evidenced by precipitating A fumigatus-specific antibodies. Six (33%) of 18 patients had serologic evidence of ABPA. Five of those 6 patients had radiologic abnormalities consistent with a diagnosis of ABPA. One patient with HIE also had asthma, thus fulfilling minimal essential criteria for concurrent ABPA.

CONCLUSIONS

Patients with HIE syndrome and CGD have a high incidence of sensitization to Aspergillus species. A clinical picture indistinguishable from ABPA may coexist or emerge in patients with CGD or HIE and create a major management dilemma because systemic corticosteroids may accelerate tissue damage and invasive fungal infections. It is important to distinguish individuals with congenital neutrophil disorders from uncomplicated classic ABPA.

Prevalence of the amylase-binding protein A gene (abpA) in oral streptococci

Salivary amylase binds specifically to a number of oral streptococcal species. This interaction may play an important role in dental plaque formation. Recently, a 585-bp gene was cloned and sequenced from Streptococcus gordonii Challis encoding a 20.5-kDa amylase-binding protein (AbpA). The goal of this study was to determine if related genes are present in other species of oral streptococci. Biotinylated abpA was used in Southern blot analysis to screen genomic DNA from several strains representing eight species of oral streptococci. This probe hybridized with a 4.0-kb HindIII restriction fragment from all 13 strains of S. gordonii tested. The probe did not appear to bind to any restriction fragments from other species of amylase-binding oral streptococci including Streptococcus mitis (with the exception of 1 of 14 strains), Streptococcus crista (3 strains), Streptococcus anginosus (1 strain), and Streptococcus parasanguinis (1 strain), or to non-amylase-binding oral streptococci including Streptococcus sanguinis (3 strains), Streptococcus oralis (4 strains), and Streptococcus mutans (1 strain). Primers homologous to sequences within the 3' and 5' ends of abpA yielded products of 400 bp following PCR of genomic DNA from the Southern blot-positive strains. Several of these PCR products were cloned and sequenced. The levels of similarity of these cloned products to the abpA of S. gordonii Challis ranged from 91 to 96%. These studies reveal that the abpA gene appears to be specific to S. gordonii and differs from genes encoding amylase-binding proteins from other species of amylase-binding streptococci.

Sex differences in cell migration in the preoptic area/anterior hypothalamus of mice

The preoptic area/anterior hypothalamus (POA/AH) sits as a boundary region rostral to the classical diencephalic hypothalamus and ventral to the telencephalic septal region. Numerous studies have pointed to the region's importance for sex-dependent functions. Previous studies suggested that migratory guidance cues within this region might be particularly unique in their diversity. To better understand the early development and differentiation of the POA/AH, cytoarchitectural, birthdate, immunocytochemical, and cell migration studies were conducted in vivo and in vitro using embryonic C57BL/6J mice. A medial preoptic nucleus became discernible using Nissl stain in males and females between embryonic days (E) E15 and E17. Cells containing immunoreactive estrogen receptor-alpha were detected in the POA/AH by E13, and increased in number with age in both sexes. From E15 to E17, examination of the radial glial fiber pattern by immunocytochemistry confirmed the presence of dual orientations for migratory guidance ventral to the anterior commissure (medial-lateral and dorsal-ventral) and uniform orientation more caudally (medial-lateral). Video microscopy studies followed the migration of DiI-labeled cells in coronal 250-microm brain slices from E15 mice maintained in serum-free media for 1-3 days. Analyses showed significant migration along a dorsal-ventral orientation in addition to medial-lateral. The video analyses showed significantly more medial-lateral migration in males than females in the caudal POA/AH. In vivo, changes in the distribution of cells labeled by the mitotic indicator bromodeoxyuridine (BrdU) suggested their progressive migration through the POA/AH. BrdU analyses also indicated significant movement from dorsal to ventral regions ventral to the anterior commissure. The significant dorsal-ventral migration of cells in the POA/AH provides additional support for the notion that the region integrates developmental information from both telencephalic and diencephalic compartments. The sex difference in the orientation of migration of cells in the caudal POA/AH suggests one locus for the influence of gonadal steroids in the embryonic mouse forebrain.

Thai language skill and HIV counseling among hilltribe people: a hospital-based study in Chiang Rai

Twenty-nine hilltribe individuals from 6 different ethnic groups were among a group of 70 patients included in an investigation of interactions between HIV-1 virus infection and common tropical illnesses. Approximately half of the hilltribe subjects (14/29) required the aid of an interpreter for HIV counseling because they could neither speak nor understand the Thai language. The 5 HIV seropositive hilltribe individuals were younger than their seronegative counterparts (26 vs 37 years respectively; p < 0.05) and had less need of an interpreter (0% vs 58% respectively; p < 0.05). Inability to speak and understand Thai limits the access of some ethnic minority subjects to HIV counseling, testing and education.

The immune response of sheep to larval challenge with Ostertagia circumcincta and O. ostertagi

One of three groups of sheep was challenged twice-weekly with infective-stage larvae (L3) of the sheep parasite O. circumcincta, another with the cattle parasite O. ostertagi while the third received no larval challenge. Positive faecal egg counts (FEC) and a rise in plasma pepsinogen levels were observed only in those animals given O. circumcincta. Anti-O. circumcincta L3 IgG titres were rapidly elevated during parasite challenge with either O. circumcincta or O. ostertagi. Throughout the experiment, no rise in anti-adult IgG titres or eosinophil numbers was observed in peripheral blood in any group. On evidence of self-cure of the trickle-infection, determined by a reduction in FEC, all groups were drenched and challenged with 15,000 O. circumcincta L3. No effect of previous challenge on parasite establishment or FEC was observed, although egg viability was significantly reduced in both groups given prior challenge. Significant differences in adult female worm length were observed between groups. Those recovered from animals previously challenged with O. circumcincta were shorter than from those given O. ostertagi which were in turn shorter than those from previously unchallenged animals. In utero egg counts were significantly lower in worms from animals previously challenged with O. circumcincta than in those from unchallenged control animals. The results indicate that a level of immunity to O. circumcincta can be conferred by exposure to O. ostertagi.

The preoptic area/anterior hypothalamus of different strains of mice: sex differences and development

While sex differences in neural morphology in the preoptic area/anterior hypothalamus (POA/AH) have been demonstrated in many species, their existence in mice have been controversial. Given the increased use of transgenic and gene-disrupted mice, we characterized sex differences using Nissl stains, and the immunocytochemical location of estrogen receptor-alpha (ER-alpha) and galanin in the POA/AH of two widely used strains, C57BL/6 and 129SvEv, and a mixed strain (C57BL/6x129Sv); the wild-type littermates of steroidogenic factor-1 (SF-1) gene-disrupted mice. Cell grouping was not a reliable marker of sex. In adults, cells located beneath the anterior commissure (AC) were reliably larger in females than males in 129SvEv, but not in the other strains. Caudally, cells in a group medial to the medial extension of the bed nucleus of the stria terminalis (BST) were significantly larger in males than females in C57BL/6J and SF-1 gene-disrupted wild-types. Cell groups discernible by embryonic day (E) 18 were not sexually dimorphic for cell size in C57BL/6J mice at E18 or postnatal day (P) 4. The pattern of distribution of cells containing ER-alpha was similar among the strains, reduced in the group medial to the BST; a pattern established by P0. Galanin-containing cells and fibers were seen from E15 to adulthood ventral to the AC. Caudally, a smaller group ventromedial to the BST was found only in 129SvEv adults. Sex differences in neural morphology which develop within the POA/AH depend upon multiple factors, particularly including genetic background.

Feasibility of a preventive HIV-1 vaccine cohort among persons attending sexually transmitted disease clinics in Thailand

Persons attending sexually transmitted disease clinics at three sites in Thailand were recruited to participate in a 1-year study of HIV-1 incidence. Between September 1995 and February 1996, 31% (371 of 1205) of eligible men and 24% (161 of 659) of eligible women agreed to participate. At enrollment, HIV-1 seropositivity was 3.8% among men and 2.5% among women. Follow-up of the 514 participants who were seronegative at baseline was 78% at the 12-month visit. During the study period, 53% of men reported 2 or more sexual partners, 31% reported sex with a commercial sex worker (CSW), and 33% with a casual partner. Of those visiting CSWs, 72% reported consistent condom use. Among women, 11% reported 2 or more sexual partners. Decreased HIV risk behaviors among men were observed during the study. Four incident infections occurred in men (1.4/100 person-years, 95% confidence interval [CI] = 0.4-3.6) and none among women. Based on the observed HIV-1 incidence, HIV vaccine efficacy trials in such populations would have to be larger than previously planned or more selective of high risk subgroups for recruitment.

Developing a pesticide policy for individuals with multiple chemical sensitivity: considerations for institutions

Institutions are increasingly being asked to accommodate individuals with multiple chemical sensitivity (MCS). Most establishments have chosen to provide such accommodations on a case-by-case basis only. This paper investigates feasible actions that may be taken by institutions to reduce exposure of MCS individuals as well as the general institutional population to pesticides and other substances. Emphasis is placed on procedures that can be instituted on a regular basis and may be combined with case-by-case management for better resolution of problems.

Application of dried blood spot specimens for serologic subtyping of human immunodeficiency virus type 1 in Thailand

Dried blood spot (DBS) specimens were assessed as an alternative to plasma for human immunodeficiency virus type 1 (HIV-1) serotyping by V3 loop peptide enzyme immunoassay. Nested PCR capable of distinguishing HIV-1 subtypes B and E was used as the reference standard. Ninety-two percent of DBS samples were typeable as either HIV-1 subtype B or E. Serotype results with DBS and plasma were identical for 254 of 257 specimens. A simple DBS collection method provides a convenient alternative for conducting HIV-1 serotype surveillance while retaining sensitivity and specificity.

Genetic and morphological characterization of Cladobotryum species causing cobweb disease of mushrooms

Cladobotryum dendroides (= Dactylium dendroides) has hitherto been regarded as the major causal agent of cobweb disease of the cultivated mushroom, Agaricus bisporus. Nucleotide sequence data for the internal transcribed spacer (ITS) regions of four Cladobotryum/Hypomyces species reported to be associated with cobweb disease, however, indicate that the most common pathogen is now C. mycophilum. This cobweb pathogen varies somewhat in conidial septation from published descriptions of C. mycophilum and lacks the distinctive colony odor. ITS sequencing revealed minor nucleotide variation which split isolates of the pathogen into three subgroups, two comprising isolates that were sensitive to methylbenzimidazole carbamate (MBC) fungicides and one comprising MBC-resistant isolates. The MBC-resistant isolates, which were only obtained from Ireland and Great Britain, clustered together strongly in randomly amplified polymorphic DNA (RAPD) PCR analysis, suggesting that they may be clonal. The MBC-sensitive isolates were more diverse. A RAPD fragment of 800 to 900 bp, containing a microsatellite and found in the MBC-resistant isolates, also indicated their clonal nature; the microsatellites of these isolates contained the same number of GA repeats. Smaller, polymorphic microsatellites, similarly comprising GA repeats, in the MBC-sensitive isolates in general correlated with their geographic origin.

The establishment rate of Ostertagia circumcincta and Trichostrongylus colubriformis in lactating Romney ewes

The ability of lactating Romney ewes to resist establishment of ingested infective-stage larvae (L3) of Ostertagia circumcincta and Trichostrongylus colubriformis was measured in the field. Three groups of seven single-lamb-bearing ewes were selected on the basis of uniformity of lambing date from a large flock held on pasture. Either 2, 4 or 6 weeks after parturition, groups of ewes were dosed with 24000 L3 of known oxfendazole-resistant parasite strains; 12000 of each species. Ten to 14 days later the ewes, along with their lambs, were transferred from the field to indoor pens. Twenty-five days after the challenge dose the ewes were drenched with oxfendazole to remove any field-derived infection and 3 days later slaughtered for worm counts. Mean establishment of the resistant parasites was low at all times, with the highest rate recorded being 6.1% for O. circumcincta 2 weeks after parturition. Establishment of O. circumcincta 4 and 6 weeks after parturition, and of T. colubriformis at all times, never exceeded 2%. By comparison, mean establishment in lambs held indoors and parasite free for 13 weeks prior to infection, was 24.9% and 47.1% for O. circumcincta and T. colubriformis, respectively. These results indicate that the lactating ewes were exhibiting a substantial ability to prevent establishment of ingested larvae. The results of this and other similar studies suggest that the dynamics of parasitism in lactating Coopworth and Romney ewes in New Zealand is substantially different to that in Merino ewes in Australia, and that these differences influence optimal strategies for the management of anthelmintic resistance in the two countries.

Moxidectin: persistence and efficacy against drug-resistant Ostertagia circumcincta

In order to determine whether the efficacy of moxidectin against Ostertagia circumcincta is enhanced by its persistency, therapeutic efficacy was compared at intervals after treatment and with that of ivermectin, a closely related but more transient endectocide. Groups of 7-month-old New Zealand Romney lambs were infected with a strain of O. circumcincta known to be resistant to moxidectin. At patency of the infections, groups of lambs were treated with either moxidectin or ivermectin at the manufacturer's recommended dosages, or left untreated. At 3, 6 and 10 days post-treatment, faecal egg count was measured and groups of lambs were slaughtered for estimation of adult worm burden. Drug-resistant worm burdens were significantly reduced in those animals treated with moxidectin but not in those treated with ivermectin. No effect of time of slaughter on worm burden was observed with either drug, demonstrating that the higher therapeutic efficacy of moxidectin against this parasite was not due to an increased period of drug exposure. Faecal egg counts in the moxidectin treated animals increased with time after treatment indicating a temporary suppression of egg output by surviving worms. The implications of these findings on selection for anthelmintic resistance are discussed.

The effect of continuous drug exposure on the immune response to Trichostrongylus colubriformis in sheep

The effect of albendazole (ABZ)-capsule (CRC) administration on parasite establishment and immunity to ABZ-resistant (RES) and -susceptible (SUS) T. colubriformis was measured in Romney lambs. During 12 weeks of twice-weekly dosing with 3000 parasite larvae (L3), eggs were observed in faeces from CRC-treated and untreated lambs given RES L3, but not CRC-treated lambs given SUS L3. Following the period of trickle challenge all lambs were drenched and, 1 week later, dosed with 20000 SUS L3. Resulting worm burdens were higher in control lambs than in those previously treated with CRCs and challenged with SUS, which in turn were higher than those in the CRC-treated or -untreated lambs previously challenged with RES L3. During the period of trickle challenge, the number of peripheral eosinophils and titres of anti-L3 and anti-adult antibody were raised only in those groups given RES L3. There was no effect of CRC administration. Following drench and challenge, antibody titres and eosinophil numbers increased in the control animals but not in those groups which had received previous trickle infection. The results demonstrate that the larval challenge alone resulted in incomplete though substantial protection against subsequent parasite challenge. The use of CRCs may potentially impact on subsequent animal performance and selection for anthelmintic resistance through a reduced level of immunity.

Management of Jehovah's Witness patients undergoing major head and neck surgery

BACKGROUND

Several diverse strategies have been recommended to manage Jehovah's Witness patients undergoing surgery when significant blood loss is expected. However, many of the proposed management strategies cannot be used when the urgent nature of the disease precludes adequate preoperative preparation of the patient. We present our experience of the management of two Jehovah's Witnesses with oral carcinoma requiring extensive resection, neck dissection, and reconstruction with free tissue transfer.

METHODS

Hypervolemic hemodilution, hypotensive anesthesia, meticulous surgical hemostasis, and antifibrinolytic therapy were used as an alternative to blood products or transfusion.

RESULTS

Radical surgical ablation and state-of-the-art reconstruction were possible, as a single-stage procedure, even though blood transfusion or blood product replacement therapy was refused.

CONCLUSION

Radical surgical ablation of oral carcinoma, with free tissue transfer reconstruction, is possible in this group of patients without the use of blood products or transfusion. There would have been no advantage in raising the red cell mass preoperatively, as the packed cell volume was ideal for free tissue transfer.

Frequency of abdominal CT findings in AIDS patients with M. avium complex bacteraemia

BACKGROUND

Use of blood culture studies for early diagnosis of Mycobacterium avium complex (MAC) infection has become important due to the recent development of effective antibiotic therapy for this condition. This study assessed the abdominal computed tomography (CT) findings in patients with AIDS who presented with bacteraemic MAC infection.

METHODS

A retrospective analysis of abdominal CT scans was performed in 24 patients who presented with MAC-positive blood culture. CT images were reviewed specifically to evaluate for lymph node enlargement and attenuation, hepatomegaly, splenomegaly, bowel wall abnormality and for any other pathological changes. Comparison was made to prior reports of the CT findings in this disease process.

RESULT

Enlarged intra-abdominal mesenteric and/or retroperitoneal lymph nodes were found in 10 patients (42%). These nodes were characterized by homogeneous, soft-tissue attenuation in eight of the 10 patients. Hepatomegaly, splenomegaly and small bowel wall thickening were noted in 12 (50%), 11 (46%) and four (14%) patients, respectively. CT findings were evaluated as normal in six (25%) patients.

CONCLUSIONS

Enlarged mesenteric and/or retroperitoneal lymph nodes in AIDS patients with bacteraemic MAC were observed much less frequently on CT than previously reported in AIDS patient populations. Normal abdominal CT findings do not exclude this diagnosis and may reflect a trend towards earlier detection of MAC disease.

CD38 expression on cryopreserved CD8+ T cells predicts HIV disease progression

Previous studies have revealed that the expression of CD38 on CD8+ T cells is a strong predictor of disease progression in human immunodeficiency virus (HIV)-infected individuals. Those studies were performed using fresh patient samples over an extended trial period. After demonstrating the validity of assay results on cryopreserved cells, we performed a retrospective study using frozen cell samples to determine the predictive value of CD38 expression in patients with CD4 counts above 400 cells/microl. The CD38 expression as measured by antibody binding capacity and the CD38 median channel were shown to be associated with time to new opportunistic infection or death (both P < 0.001). These results suggest that CD38 expression on CD8+ T cells, whether fresh or frozen, provides a useful predictor of HIV disease progression.

Clinical factors associated with positive bile cultures during primary percutaneous biliary drainage

PURPOSE

To evaluate the utility of routine bile cultures and to determine the risk factors for bacterial colonization of the bile as well as the biliary flora in patients with biliary obstruction undergoing primary percutaneous biliary drainage.

MATERIALS AND METHODS

Between October 1995 and January 1997, bile cultures were prospectively obtained in all patients undergoing percutaneous biliary drainage. Seventy-six patients underwent 86 procedures. Culture results were correlated with clinical, laboratory, and demographic variables. The antibiotic sensitivities of cultured organisms were examined.

RESULTS

Fever, previous endoscopic or percutaneous biliary instrumentation, and bilioenteric anastomosis were significant predictors of a positive bile culture. In the absence of any of these indicators, bile cultures were unlikely to be positive. Enterococcus species was the organism isolated most commonly. Yeast, gram-negative aerobic bacilli, and Streptococcus viridans followed in frequency.

CONCLUSION

Bile cultures provide valuable information that was useful for planning antibiotic prophylaxis and treatment. The likelihood of positive bile cultures can be predicted based on certain clinical variables. Continued investigation is needed to better predict bacterial flora in individual patients. Given the association between previous instrumentation and biliary colonization, noninvasive imaging modalities should be exhausted before invasive procedures are performed for solely diagnostic purposes in patients with biliary obstruction.

The effect of continuous drug exposure on the immune response of lambs challenged with drug-susceptible or drug-resistant nematode larvae

Groups of lambs either with or without controlled-release albendazole (ABZ) capsules (CRCs) were challenged twice weekly for 6 weeks with either drug-susceptible or drug-resistant Ostertagia circumcincta and Trichostrongylus colubriformis. Groups with and without CRCs remained unchallenged as controls. There was minimal establishment of drug-susceptible parasites of either species in those lambs with CRCs. However, drug-resistant parasites of both species established adult worm burdens in the presence of the capsules. The humoral immune response, as measured by the serum antilarval (L3) antibody (Ab) titre, was pooled for weeks 4-6 and compared for each group. With the exception of anti-T. colubriformis Ab in group 2, anti-L3 Ab titres were significantly higher in all the parasite-challenged groups as compared to the control animals. Also, with the exception of anti-resistant O. circumcincta Ab levels in the CRC-treated animals (group 5), no significant difference was observed in Ab titres between the four groups challenged with either resistant or susceptible larvae. The results demonstrate the inability of CRCs to prevent establishment of drug-resistant parasites and that immune stimulation is not inhibited by the capsules.

HIV vaccine development: a subtype E-specific strategy

The pandemic of HIV/AIDS consists of multiple foci with distinct epidemiological characteristics. Among the approximately one million Southeast Asians infected with HIV, subtype (clade) E infections predominate. This subtype, a recombinant virus comprised of a clade A core (gag) gene and a mosaic clade A/clade E envelope (env) gene, became broadly epidemic in Thailand beginning in 1989. Since then, subtype E HIV has become increasingly prevalent throughout Southeast Asia. Consistent with the recent introduction of clade E HIV, the diversity of Southeast Asian subtype E viruses is narrow (6% nucleotide diversity across env). Since neutralizing antibodies may play a protective role against HIV infection, and are relatively clade specific for genotype E viruses, a subtype E-derived candidate vaccine tested in Southeast Asia would provide an optimal test of vaccine concept. It would also provide, for the first time to a developing region of the world, a non-B clade candidate vaccine designed specifically for the local epidemic. A consortium of industry (Chiron Vaccines and Pasteur Merieux Connaught), academic (Mahidol and Chiang Mai Universities) and military (United States and Royal Thai Army Medical Departments) medicine is working together to develop and test HIV vaccines for the genotype E epidemic. A genotype B recombinant glycoprotein (rgp)120 candidate vaccine has undergone phase I/II testing in Thailand and confirmed to be safe and immunogenic in this ethnic group. An rgp120 (E) has been produced and a phase I/II trial of the bivalent product (B/E) is in the final stages of approval. This vaccine construct is designed to elicit humoral immune responses. To augment these antibody responses with CD8+ CTL responses, an E-specific, live-vectored vaccine is being developed which will be used in conjunction with rgp120 in a second vaccine approach. Canarypox (ALVAC) constructs containing multiple HIV genes (gag/pol/env) currently designed for the subtype B epidemics will be modified to contain a clade E env gene sequence. After predetermined milestones have been met, these two subtype E-specific candidate vaccines will be assessed for protection in a large collaborative efficacy trial. Since neither animal models nor laboratory assays are validated as predictive of HIV vaccine efficacy, it must be through such a phase III trial that vaccine-induced protection and immunologic correlates will be determined.

A PCR-based method to distinguish fungi of the rice sheath-blight complex, Rhizoctonia solani, R. oryzae and R. oryzae-sativae

Identification of Rhizoctonia solani, R. oryzae and R. oryzae-sativae, components of the rice sheath disease complex, is extremely difficult and often inaccurate and as a result may hinder the success of extensive breeding programmes throughout Asia. In this study, primers designed from unique regions within the rDNA internal transcribed spacers have been used to develop a rapid PCR-based diagnostic test to provide an accurate identification of the species on rice. Tests on the specificity of the primers concerned showed that they provide the means for accurate identification of the Rhizoctonia species responsible for sheath diseases in rice.

Septicemia and septic shock in pediatric patients: 140 consecutive cases on a pediatric hematology-oncology service

PURPOSE

This report describes the incidence of septic shock in pediatric hematology-oncology patients with positive blood cultures and investigates parameters of potential use in early diagnosis of gram-negative (GN) bacteremia and septic shock.

PATIENTS

In a 12-month period, 140 consecutive episodes of septicemia (135 bacterial and 5 fungal) were seen in 100 patients. The absolute neutrophil count (ANC) was > 500/microl in 89 episodes (65%).

RESULTS

Septic shock developed in patients with positive blood cultures with an overall incidence of approximately 19%. Of the 12 bacteremic patients who required transfer to the intensive care unit, 83% had a GN isolate recovered. The incidence of septic shock was not significantly lower in the group of patients with ANC > 500/microl. Low serum bicarbonate correlated with GN infection in patients with bacteremia.

CONCLUSIONS

GN organisms were the major cause of septic shock in a group of pediatric hematology-oncology patients with positive blood cultures although they were recovered less frequently than gram-positive organisms. In our study, non-neutropenic patients with indwelling catheters were at approximately the same risk for GN shock as neutropenic patients. Monitoring blood carbon dioxide content may be useful in the early diagnosis of GN infection.

An investigation of vancomycin-resistant Enterococcus faecium within the pediatric service of a large urban medical center

BACKGROUND

Between 1990 to 1992 and 1993 to 1995 there was a >5-fold increase (16.7% to 89.8%) in vancomycin-resistant Enterococcus faecium isolates as a percentage of all isolates of vancomycin-resistant enterococci on the pediatric units of The New York Hospital-Cornell Medical Center (NYH-CMC). A molecular epidemiologic investigation was undertaken to determine the extent to which this increase was associated with the spread of a vanA-containing clone of vancomycin-resistant E. faecium that had been previously defined in adults hospitalized at NYH-CMC or with the spread of another vanA clone that had been defined in children hospitalized on the pediatric service at Memorial Sloan-Kettering Cancer Center, which shares a common pediatric intensive care unit and pediatric house staff with NYH-CMC.

METHODS

Molecular genotyping of vancomycin-resistant E. faecium isolates obtained from pediatric patients from 1993 to 1995 was performed by pulsed field gel electrophoresis of chromosomal SmaI digests. Southern hybridization was performed using vanA- and vanB-specific probes. Medical records of patients were reviewed for pertinent clinical and demographic information.

RESULTS

A single vanB clone of vancomycin-resistant E. faecium was responsible for 17 (77.3%) of 22 isolates in the neonatal intensive care unit (NICU) of NYH-CMC. Two other vanB strains of vancomycin-resistant E. faecium and 2 vanA strains were identified among the 5 remaining NICU isolates. Vancomycin-resistant E. faecium isolates from the other pediatric units represented a heterogeneous population of primarily vanA strains, but vanA clonal strains previously identified from patients on adult services at NYH-CMC and from children hospitalized at Memorial Sloan-Kettering Cancer Center were not detected.

CONCLUSION

A newly identified vanB clone was responsible for the increase in vancomycin-resistant E. faecium isolates in the NICU of NYH-CMC. The increase of vancomycin-resistant E. faecium among children hospitalized at NYH-CMC was unrelated to the spread of vancomycin-resistant E. faecium among adults in the same hospital or among children at an affiliated facility cared for by the same house staff and sharing a common pediatric intensive care unit.

The BAOMS United Kingdom survey of facial injuries part 1: aetiology and the association with alcohol consumption. British Association of Oral and Maxillofacial Surgeons

OBJECTIVE

To determine the age and sex distribution, timing, causes, geographical location, and nature of facial injuries in the UK and to determine the association of these factors with alcohol consumption by the patient or any other involved person.

DESIGN

A 12-section proforma was completed on all patients with facial injuries covering their age and sex, time and day of injury and presentation, the cause and type of injury and where it occurred, the treatment the patient received, any other injuries, and alcohol consumption by the patient and any other involved person. The total attendances for the study week and the catchment population for each A&E department were recorded.

SETTING

163 of the A&E departments in the UK served by 137 of the UK's oral and maxillofacial departments.

SUBJECTS

All patients who presented with facial injuries to these 163 A&E departments in England, Scotland, Wales and Northern Ireland over the study week from 09.00 hours on Friday 12 September 1997 to 08.59 hours on Friday 19th September 1997.

RESULTS

6114 patients with facial injuries presented over the week, out of a total of 152,692 A&E attendances. The male:female ratio was 68:32. This rose to 79:21 in assault cases. The mean age of all patients was 25.3 years, of males 23.2 years, and of females 29.8 years. Forty per cent of the facial injuries were caused by falls. A large proportion of these happened to the under-5 age group in the home. Eleven per cent of all falls were associated with alcohol consumption. Twenty-four per cent of the facial injuries were caused by assault. The commonest sites for assault were the street followed by public drinking establishments. More women than men were assaulted at home. Fifty-five per cent of assaults were related to alcohol consumption. Eight per cent of assaults were with bottles or glasses. Five per cent of the facial injuries occurred in road traffic accidents (RTAs). Fifteen per cent of RTA victims had consumed alcohol. The 15-25 age group suffered the greatest number of facial injuries caused by assault and RTAs and had the highest number associated with alcohol consumption. At least 22% of all the facial injuries in all age groups were related to alcohol consumption within 4 hours of the injury. In the over 15 age groups, alcohol consumption was associated with 90% of facial injuries occurring in bars, 45% on the street, and 25% in the home. Assault, RTA and alcohol consumption conveyed an increased risk of serious facial injury.

CONCLUSIONS

Campaigns should be instituted to educate young people about the link between excessive alcohol consumption, assault, road traffic accidents and serious facial injury.

Use of SSU rDNA group-I intron to distinguish Monilinia fructicola from M. laxa and M. fructigena

Monilinia fructicola, M. laxa and M. fructigena are the causal agents of brown rot of pome and stone fruits. M. fructicola is not present in Europe and is classed as a quarantine pathogen in EU countries. A 418-bp group-I intron has been located in the small subunit (SSU) rDNA gene of M. fructicola which is absent from M. laxa and M. fructigena. PCR primers specific to the 3'-region of the intron together with the SSU rDNA primer NS5 were able to amplify a 444-bp product from M. fructicola and fruit tissue infected with M. fructicola but not from the other two species. This allows for the rapid and sensitive detection of this pathogen in planta.

Valve obturation of the nasopharynx

Complete obturation of the nasopharynx can cause functional problems with breathing and swallowing due to obstruction of the nasal airway. A technique is described whereby a one way valve was incorporated in an obturator to allow normal nasal inspiration whilst maintaining an oropharyngeal seal during swallowing and speech.

Importance of the C-1 substituent in classical cannabinoids to CB2 receptor selectivity: synthesis and characterization of a series of O,2-propano-delta 8-tetrahydrocannabinol analogs

The separation of the mood-altering effects of cannabinoids from their therapeutic effects has been long sought. Results reported here for a series of C-9 analogs of the cyclic ether O,2-propano-delta 8-tetrahydrocannabinol (O,2-propano-delta 8-THC) point to the C-1 position in classical cannabinoids as a position for which CB2 subtype selectivity occurs within the cannabinoid receptors. O,2-Propano-11-delta 8-THC, O,2-propano delta 9,11-THC, O,2-propano-9-oxo-11-nor-hexahydrocannabinol (O,2-propano-9-oxo-11-nor-HHC), and O,2-propano-9 alpha- and O,2-propano-9 beta-OH-11-nor-HHC were synthesized and evaluated in radioligand displacement assays for affinity at the CB1 and CB2 receptors and in the mouse vas deferens in vitro assay and the mouse tetrad in vivo assay for cannabinoid activity. Evaluation of binding affinity at the CB1 and CB2 receptors revealed that each compound possesses a modest increased affinity for the CB2 receptor. Analogs which contained an oxygen attached to C-9 (i.e., oxo and hydroxy derivatives) showed the highest affinity and selectivity for CB2 (for O,2-propano-9-oxo-11-nor-HHC, Ki(CB1) = 90 nM, Ki(CB2) = 23 nM, selectivity ratio 3.9; for O,2-propano-9 beta-OH-11-nor-HHC, Ki(CB1) = 26 nM, Ki(CB2) = 5.8 nM, selectivity ratio 4.5). Each compound was found to produce a dose-dependent inhibition of electrically-evoked contractions of the mouse isolated vas deferens when administered at submicromolar concentrations. This inhibition could readily be prevented by the selective CB1 cannabinoid receptor antagonist SR-141716A. The analogs exhibited unique in vivo profiles with O,2-propano-delta 9,11-THC exhibiting antinociception with reduced activity in three other in vivo measures and O,2-propano-9 beta-OH-HHC exhibiting lack of dose responsiveness in all measures. The CB2 selectivities in the O,2-propano analogs may be due to differences in solvation/desolvation that occur when the ligands enter the CB1 vs CB2 binding site. Alternatively, the CB2 selectivities may be a results of an amino acid change from a hydrogen bond-accepting residue in CB1 to a hydrogen bond-donating residue in CB2.

Human immunodeficiency virus RNA levels in US adults: a comparison based upon race and ethnicity

Volunteers in a natural history study of human immunodeficiency virus type 1 (HIV-1) at two military medical centers were studied to determine whether plasma HIV-1 RNA levels differ among racial and ethnic groups of US adults infected with HIV-1. Cross-sectional analyses of plasma HIV-1 RNA and CD4 cell counts were done using demographic and clinical data collected during study visits. Age, gender, CD4 cell count, seroconversion status, and use of antiretroviral therapy were studied in 545 military members (46% white, 49% black, and 6% Hispanic). No association was found between HIV-1 RNA levels and race or ethnicity among infected adults for whom access to care and socioeconomic status were not confounding factors.

1997 guidelines for the use of antimicrobial agents in neutropenic patients with unexplained fever. Infectious Diseases Society of America

This is the first in a series of practice guidelines commissioned by the Infectious Diseases Society of America through its Practice Guidelines Committee. The purpose of these guidelines is to provide assistance to clinicians when making decisions on treating the conditions specified in each guideline. The targeted providers are internists, pediatricians, and family practitioners. The targeted patients and setting for the fever and neutropenia guideline are hospitalized individuals with neutropenia secondary to cancer chemotherapy. Panel members represented experts in adult and pediatric infectious diseases and oncology. The guidelines are evidence-based. A standard ranking system was used for the strength of the recommendations and the quality of the evidence cited in the literature reviewed. The document has been subjected to external review by peer reviewers as well as by the Practice Guidelines Committee and was approved by the IDSA Council. An executive summary, algorithms, and tables highlight the major recommendations. The guideline will be listed on the IDSA home page at http://www.idsociety.org.

Viral RNA in the resolution of human immunodeficiency virus type 1 diagnostic serology

BACKGROUND

Assays for human immunodeficiency virus (HIV) antibody testing are characterized by very high levels of sensitivity and specificity. Nonetheless, serologic testing of HIV-infected individuals before they produce multispecific HIV antibodies will not detect and confirm those individuals as positive for HIV. This study was carried out to determine whether viral RNA in such specimens is detectable in a quantitative RNA polymerase chain reaction assay.

STUDY DESIGN AND METHODS

Study specimens were identified through the United States military HIV testing program. Thirty-five individuals were studied whose HIV type 1 (HIV-1) infection status was serologically inconclusive at initial testing (i.e., reactive on enzyme immunoassay, nondiagnostic or nonreactive on Western blot), but who were documented to be infected (n = 15) or uninfected (n = 20) through the testing of subsequently collected (follow-up) sera. HIV-1 RNA was detected in sera by the use of a commercially available, quantitative, reverse transcriptase-polymerase chain reaction assay.

RESULTS

Specimens from 15 individuals subsequently confirmed to be positive for HIV antibody were all positive for HIV-1 RNA. Specimens from 19 of 20 individuals subsequently confirmed to be negative for HIV antibody were negative for HIV-1 RNA. In the one HIV-1 RNA-positive serum from this group, the RNA copy number was low; specimen contamination during prior laboratory testing was suspected.

CONCLUSION

Viral RNA was detected in specimens collected for serologic diagnosis of HIV infection in which no special precautions had been taken to preserve the nucleic acid. Such molecular methods potentially add a much needed tool to current HIV testing algorithms.

Prophylactic efficacy of persistent anthelmintics against challenge with drug-resistant and susceptible Ostertagia circumcincta

Three groups of newly-weaned Romney lambs were given either a standard oral dose of albendazole, a controlled-release capsule containing albendazole, or a standard oral dose of moxidectin. At 10, 20, 30 and 40 days after treatment, sub-groups of lambs were given 10,000 infective-stage larvae of either a drug-resistant or a drug-susceptible strain of Ostertagia circumcincta. The recommended oral dose of albendazole removed 32 per cent of the resistant strain and over 99.9 per cent of the susceptible O. circumcincta. The recommended oral dose of moxidectin removed 91 per cent of the resistant strain and over 99.9 per cent of the susceptible parasites. None of the lambs treated with controlled-release capsules was challenged at 20 or 30 days after treatment. Twenty-one days after challenge, samples of faeces were taken to determine the presence of nematode eggs and cultured to establish the proportion of eggs developing to infective-stage larvae (L3). Abomasa were recovered after slaughter and worm burdens determined. In the lambs given controlled-release capsules only the resistant parasites were able to establish, and there were significantly fewer than in the lambs treated orally with albendazole. The proportion of the eggs from resistant parasites which developed to L3 was not reduced by the presence of the capsules. Oral moxidectin provided no protection against the establishment of the resistant strain and viable L3 were recovered after challenge with resistant parasites 10 days after treatment; however, the establishment of susceptible O. circumcincta was reduced by more than 99 per cent. The establishment of the susceptible parasites in the lambs treated with moxidectin increased with time and was not significantly lower than in the other groups by 30 days after treatment.

Rapid disease progression without seroconversion following primary human immunodeficiency virus type 1 infection--evidence for highly susceptible human hosts

A patient is described who rapidly progressed from primary human immunodeficiency virus (HIV) type 1 infection to death without seroconversion but with consistently high plasma viremia. His asymptomatic sex partner had been HIV-1 seropositive for >8 years prior to transmission. Analysis of viral sequences from these subjects and controls confirmed the transmission event. Although the biologic properties of the patient's virus were unremarkable, he had poor functional immune responses to HIV and an HLA haplotype associated with rapid disease progression. The disparity between immune responses and clinical course in this transmission pair, coupled with infection with an unremarkable HIV-1 isolate, underscores the crucial importance of host factors in HIV-1 pathogenesis.