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Biomedical subjects

H Holmes

Publications and source records attributed to H Holmes.

At least 19 recordsLinked to original sources
PubMed2006

Interventions for the prevention and management of oropharyngeal candidiasis associated with HIV infection in adults and children.

BACKGROUND: Oral candidiasis (OC) associated with human immunodeficiency virus (HIV) infection occurs commonly and recurs frequently, often presenting as an initial manifestation of the disease. Left untreated these lesions contribute considerably to the morbidity associated with HIV infection. Interventions aimed at preventing and treating HIV-associated oral candidal lesions form an integral component of maintaining the quality of life for affected individuals. OBJECTIVES: To determine the effects of any intervention in preventing or treating OC in children and adults with HIV infection. SEARCH STRATEGY: The search strategy was based on that of the HIV/AIDS Cochrane Review Group. The following electronic databases were searched for randomised controlled trials for the years 1982 to 2005: Medline; AIDSearch; EMBASE and CINAHL. The Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effectiveness and the Cochrane Central Register of Controlled Trials (CENTRAL) was also searched through May 2005. The abstracts of relevant conferences, including the International Conferences on AIDS and the Conference on Retroviruses and Opportunistic Infections, as indexed by AIDSLINE, were also reviewed. The strategy was iterative, in that references of included studies were searched for additional references. All languages were included. SELECTION CRITERIA: Randomised controlled trials (RCTs) of palliative, preventative or curative therapy were considered, irrespective of whether the control group received a placebo. Participants were HIV positive adults. DATA COLLECTION AND ANALYSIS: Two authors independently assessed the methodological quality of the trials and extracted data. Study authors were contacted for additional data where necessary. MAIN RESULTS: Four trials were conducted in developing countries with eleven of the trials conducted in the United States of America. Twenty eight trials (n=3225) were included. Nineteen trials investigated treatment and nine trials the prevention of OC. One trial, comparing fluconazole and ketoconazole, investigated the treatment of OC in children. Eighteen of the included studies reported CD4 cell counts. None of the included studies investigated the effects of HAART or any other form of antiretroviral treatment on OC treatment or prevention.TreatmentTreatment was assessed in the majority of trials looking at both clinical and mycological cures. In the majority of comparisons there was only one trial. Compared to nystatin, fluconazole favoured clinical cure in adults(1 RCT; n=167; RR 1.69; 95% CI 1.27 to 2.23). There was no difference with regard to clinical cure between fluconazole compared to ketoconazole (2 RCTs; n=83; RR 1.27; 95% CI 0.97 to 1.66), itraconazole (2 RCTs; n=434; RR 1.05; 95% CI 0.94 to 1.16) or clotrimazole (2 RCTs; n=358; RR 1.14; 95% CI 0.92 to 1.42). When compared with clotrimazole, both fluconazole (2 RCTs; n=358; RR 1.47; 95% CI 1.16 to 1.87) and itraconazole (1 RCT; n=123; RR 2.20; 95% CI 1.43 to3.39) proved to be better for mycological cure. Both gentian violet (1 RCT; n=96; RR 5.28; 95% CI 1.23 to 22.55) and ketoconazole (1 RCT; n=92; RR 5.22; 95% CI 1.21 to 22.53) were superior to nystatin in bringing about clinical cure. PreventionSuccessful prevention was defined as the prevention of a relapse while receiving prophylaxis. Fluconazole was compared with placebo in one trial (5 RCTs; n=599; RR 0.61; 95% CI 0.5 to 0.74) and with no treatment in another (1 RCT; n=65; RR 0.16; 95% CI 0.08 to 0.34). In both instances the prevention of clinical episodes was favoured by fluconazole. Comparing continuous fluconazole treatment with intermittent treatment (1 RCT; n=62; RR 0.37; 95% CI 0.15 to 0.92), prevention is favoured by the continuous treatment. AUTHORS' CONCLUSIONS: Implications for practiceDue to only one study in children it is not possible to make recommendations for treatment or prevention of OC in children. Amongst adults, there were few studies per comparison. Due to insufficient evidence no conclusion could be made about the effectiveness of clotrimazole, nystatin, amphotericin B, itraconazole or ketoconazole with regard to OC prophylaxis. In comparison to placebo, fluconazole is an effective preventative intervention. However, the potential for resistant Candida organisms to develop, as well as the cost of prophylaxis, might impact the feasibility of implementation. No studies were found comparing fluconazole with other interventions. Direction of findings suggests that ketoconazole, fluconazole, itraconazole and clotrimazole improved the treatment outcomes. Implications for researchThere is an urgent need for gentian violet and other less expensive anti-fungal drugs for OC treatment to be evaluated in larger studies. More well designed treatment trials with larger sample size are needed to allow for sufficient power to detect differences in not only clinical, but also mycological response and relapse rates. There is also a strong need for more research to be done on the treatment and prevention of OC in children as it is reported that OC is the most frequent fungal infection in children and adolescents who are HIV positive. More research on the effectiveness of less expensive interventions also needs to be done in resource-poor settings. Currently few trials report outcomes related to quality of life, nutrition, or survival. Future researchers should consider measuring these when planning trials. Development of resistance remains under-studied and more work must be done in this area. It is recommended that trials be more standardised and conform more closely to CONSORT as this will improve research and also clinical practice.

Adult↗
PubMed2006

Comparative analysis of HIV-1 recombinant envelope glycoproteins from different culture systems.

The productivity of stable Chinese hamster ovary cell lines secreting HIV-1 monomeric (IIIB gp120) and oligomeric (UG21 gp140) recombinant envelope glycoproteins was compared in serum-containing (S+), serum-free (S-) and protein-free (P-) culture media. UG21 gp140 expression was greatest in S+ medium, while IIIBgp120 production was lower than gp140 in all three media but highest in S-. UG21 gp140 production was highest in standard 850-cm2 roller bottle cultures in S+ media, peaking after 14 days of incubation, while expression levels in the three media were 0.5 (S+), 0.4 (S-) and 0.2 (P-) mg/l, from which 90, 80 and 12% of gp140, respectively, could be purified by immunoaffinity chromatography. Purified UG21 gp140 from S+ and S- media possessed biological functionality as evidenced by CD4 and monoclonal antibody (Mab) binding. In contrast, UG21 gp140 from P- medium appears to be misfolded and non-functional. Despite the possession of a different N-linked glycan profile, UG21 gp140 from S- media shows very similar CD4 and Mab binding characteristics to S+ UG21 gp140. The relevance of these findings to HIV vaccine development is discussed.

Animals↗
PubMed2004

Expression and characterisation of recombinant oligomeric envelope glycoproteins derived from primary isolates of HIV-1.

The production, purification and characterisation of recombinant gp140 oligomeric envelope glycoproteins derived from six primary isolates of HIV-1 (covering clades A, B, C, D, F and O) are described. Using a Chinese hamster ovary cell expression system, expression levels of between 0.1 and 1 mg/l cell-conditioned culture media were obtained, and purified to >95% by affinity chromatography. A, B, D, F and O clade gp 140s were found to be multimeric, bind to a panel of defined env-specific monoclonal antibodies and interact with CD4 and CXCR4, demonstrating correct folding. Their immunogenicity was confirmed by the generation of high-titre anti-gp140 antibodies in rabbits. The C clade gp140 was incorrectly folded and poorly antigenic. Despite the presence of an unmodified gp120/41 cleavage site, only the B clade gp140 showed significant processing to gp120 and gp41. Each gp140 has a specific pattern of oligomerisation, and varies in its resistance to reducing agents and salt concentration. The binding of gp140 to soluble and cell-surface CD4 and CXCR4 is related to the degree of oligomerisation. The C1 and C5 regions, CD4 binding domain and the epitope defined by the 2G12 monoclonal antibody were well exposed, but the C-terminal region of the extracellular domain of gp41 appears to be occluded by oligomerisation. These reagents have potential as immunogens for use in vaccine development.

Animals↗
PubMed2002

A new cell line-based neutralization assay for primary HIV type 1 isolates.

Simple and standardized assays for detection and quantification of neutralizing antibodies to primary HIV-1 isolates are needed in research on HIV-1 vaccines and pathogenesis. Here we describe a new HIV-1 neutralization assay that is based on plaque formation in U87.CD4-CCR5 and U87.CD4-CXCR4 cells, which is an attractive alternative to peripheral blood mononuclear cell-based assays. Infected cells form syncytia, that is, plaques, that can be stained with hematoxylin and enumerated by light microscopy. Neutralization is determined by the ability of a serum to reduce the number of plaque-forming units (PFU) relative to controls exposed to medium or negative serum. The intraassay variation of the plaque-forming unit determinations was tested with 15 serum-virus combinations and showed good reproducibility. The differences ranged from -19 to +27% and had a standard deviation of +/- 9.1%. On the basis of these data the cutoff for neutralization (i.e., plaque reduction) was set to 30% (3.3 standard deviations). Virus titration experiments showed that neutralization results were dependent on virus dose and therefore the neutralization assays should be performed with a virus dose of 10-100 PFU/well. The reproducibility of the new neutralization assay was tested with 4 primary viruses and 9 sera for a total of 20 virus-serum combinations. The mean difference in neutralization (i.e. plaque reduction) determinations performed on different days was as small as 11%. None of 10 Swedish sera and 1 Ugandan plasma pool from HIV-1-uninfected subjects were positive for neutralization, indicating that the assay has high specificity. In summary, the new U87.CD4 cell line-based neutralization assay for primary HIV-1 isolates is a highly reproducible, sensitive, and high-throughput assay that is well suited for large-scale HIV-1 neutralization studies.

CD4-Positive T-Lymphocytes↗
PubMed2001

Characterization of human monoclonal antibodies selected with a hypervariable loop-deleted recombinant HIV-1(IIIB) gp120.

Recombinant gp120 of the HIV-1(IIIB) isolate (BH10 clone) has been mutated to form the PR12 protein with the first 74 C-terminal amino acids and the V1, V2 and V3 hypervariable loops deleted. A variety of studies have shown that the CD4 binding domain (CD4bd) is very well exposed in PR12 in contrast to rgp120(LAI). Using PR12 for selection of human monoclonal antibodies (MAbs) from HIV-infected individuals, five MAbs were generated with specificities to the epitopes overlapping the CD4bd (1570A,1570C,1570D,1595 and 1599). The three MAbs, 1570A, C and D, generated from one HIV-infected individual, represent one MAb as determined by sequence analysis of the V(H)3 region. Since the epitopes overlapping the CD4bd exhibit variability among HIV-1 clades, the specificity of anti-CD4bd MAbs were distinguished by differing patterns of binding to recombinant envelope proteins derived from clade A, B, C, D and E viruses. The PR12-selected MAbs were also compared with a panel of gp120-selected anti-CD4bd MAbs and showed a different range of specificities. MAb 1599 is clade B specific, MAb 1595 reacts with the A, B and D clades, while MAb 1570 recognises the most conserved epitope, as it binds to all proteins. The results show that the exposure of different epitopes in the CD4bd of the PR12 protein allows this protein to serve as an immunogen and to induce anti-CD4bd antibodies.

Antibodies, Monoclonal↗
PubMed2001

An international collaborative study to establish the 1st international standard for HIV-1 RNA for use in nucleic acid-based techniques.

Twenty-six laboratories from 10 different countries participated in a collaborative study to establish the 1st International Standard for HIV-1 RNA for use in nucleic acid-based techniques (NAT). Three candidate preparations were tested all based on genotype B viruses. The candidates were tested by each laboratory at a range of dilutions in four independent assays and the results collated and analysed statistically. All three candidates gave results that were tightly grouped, with little difference between the results from different laboratories or from the use of different assays. Studies of relative potency showed good agreement between laboratories. There were no significant differences between five commercial assay types, except that candidate XX showed a slightly lower potency compared to YY and ZZ with a single commercial assay. The reason for this was not established. Degradation studies showed that the freeze-dried preparations were stable at -20,4 and 20 degrees C for 26 weeks, the longest period studied, but that they became difficult to reconstitute after 3 weeks at 45 degrees C and 9 weeks at 37 degrees C. As a result of the study, the World Health Organisation (WHO) Expert Committee on Biological Standardisation (ECBS) established the preparation referred to as candidate YY (NIBSC Code No. 97/656) as the 1st International Standard for HIV-1 RNA for use with NAT with an assigned potency of 100000 International Units per vial.

HIV Infections↗
PubMed2001

National Institute for Biological Standards and Control/UK Blood Transfusion Service working standards for HBsAg, anti-HCV and anti-HIV-1 ('go/no-go' controls).

BACKGROUND AND OBJECTIVES: The positive controls supplied with the commercial kits used in the testing of blood donations for markers of viral infection are usually of high reactivity and do not give users a reliable indication of optimal performance of the kit on a day-to-day basis. MATERIALS AND METHODS: The National Institute for Biological Standards and Control has developed working standards for hepatitis B surface antigen (HBsAg), anti-hepatitis C virus (anti-HCV) and anti-human immunodeficiency virus type 1 (anti-HIV-1) for the UK Blood Transfusion Services for daily use in every test. RESULTS: Data from the use of these reagents are collated and quarterly reports are issued. CONCLUSIONS: The centralized collation, analysis and reporting of the results from users of working standards facilitate the continual assessment of the responses obtained by individual laboratories, comparisons of the interlaboratory performance and the performance of different manufacturers' kits at a national level. This information complements the data on infection surveillance and initial/repeat reactivities using the same kits.

Biological Assay↗
PubMed2001

Development of multiplexed nucleic acid testing for human immunodeficiency virus type 1 and hepatitis C virus.

BACKGROUND AND OBJECTIVES: In most Western countries, blood donations are routinely screened for hepatitis C virus (HCV) RNA by polymerase chain reaction (PCR) or other nucleic acid tests. We describe the development of a multiplexed assay for human immunodeficiency virus type 1 (HIV-1) and HCV in an internally controlled PCR suitable for large-scale blood donor screening. MATERIALS AND METHODS: The HIV/HCV multiplexed PCR used primers from highly conserved regions in the long terminal repeat region. The National Institute for Biological Standards and Controls (NIBSC) International HIV-1 RNA standard, run control and HIV-1 subtype panel were used for assay evaluation. RESULTS: The HIV-1 PCR showed a sensitivity of 24 IU/ml for HIV-1 RNA (a dilution where 95% of replicate reactions were positive), which was at least five times more sensitive than the Roche Monitor version 1.5 (using the ultrasensitive extraction protocol) and Organon NASBA assays. The assay was capable of detecting all subtypes of HIV-1 (A to H), as well as the more divergent group N and O variants. The sensitivity of the PCR was unaffected by multiplexing with HCV primers and by the presence of a bovine viral diarrhoea virus (BVDV) internal control. CONCLUSION: We have developed a highly sensitive multiplexed PCR for HIV-1 and HCV RNA screening that can be introduced into current PCR-based blood donor screening at minimal cost and without significant operational changes.

Conserved Sequence↗
PubMed2000

Muscle force and range of motion as predictors of function in older adults.

BACKGROUND AND PURPOSE: Musculoskeletal impairments and functional limitations are linked to disability in older adults. The purposes of this study were to identify the extremity musculoskeletal impairments that best predict functional limitations in older adults and to assess the validity of measurements obtained for the Physical Performance Test (PPT) as a predictor of disability. SUBJECTS AND METHODS: Eighty-one older adults residing in independent and dependent care facilities were tested for extremity muscle force, range of motion, and function. Data were analyzed using multiple regression analysis to identify extremity impairments that predicted function scores and logistic regression analysis to determine whether PPT scores predicted subjects' living situation as dependent versus independent. RESULTS: Subject age, lower-extremity muscle force, and lower-extremity range of motion explained 77% of the variance in function as measured by the PPT. Results differed when analysis was done by subject living situation, with a higher percentage of the variance in function scores explained by musculoskeletal measures for the dependent living group as compared with the independent living group. CONCLUSION AND DISCUSSION: Extremity musculoskeletal impairments have a strong relationship to function, especially in older adults living in dependent care settings. The results of this study can be used to design interventions to address the musculoskeletal disorders most related to function in the older population.

Activities of Daily Living↗
PubMed2000

Oncology legislative update.

This article reviews current legislative and regulatory issues of importance to the oncology community. Topics include patient protection, Medicare support of clinical trials, research data protection, the Medical Innovation Tax Credit, National Cancer Institute appropriations, and medical record privacy issues. Other topics discussed included funding for stem-cell research, genetic therapy oversight, and coverage for uninsured patients.

Budgets↗
PubMed1999

An international collaborative study on the detection of an HIV-1 genotype B field isolate by nucleic acid amplification techniques.

An international collaborative study to assess inter-laboratory variation in the sensitivity of gene amplification assays for the detection of HIV-1 RNA sequences was conducted using a panel of eight duplicate dilutions of an HIV-1 genotype B clinical isolate and negative control samples. Twenty-five laboratories participated in the study and used a variety of in-house assays and commercial assay systems. With few exceptions, the assays were more sensitive than a p24 antigen assay. Overall, the PCR-based Amplicor Monitor assay was the most sensitive and gave the highest mean copy number for any one sample. Some of the in-house assays gave results comparable with the Monitor assay whilst the NASBA and bDNA assays appeared to be less sensitive. As a result of this study, an HIV-1 Working Reagent for the standardisation of nucleic acid amplification assays was developed and assessed in a subsequent study. Similar differences in sensitivity between the different assay systems was observed. The discrepancies in viral copy number obtained using the Working Reagent highlights the need for an International Standard against which all Working Reagents may be calibrated.

Adult↗
PubMed1999

Are the oral manifestations associated with HIV infection really relevant to the practising South African dentist? A comparative analysis of oral HIV studies in South Africa.

This comparative analytical review of oral HIV in South Africa, Africa and the West shows that relatively little work has been done on the African continent in this field of study. Direct epidemiological comparisons of these studies with each other are difficult but were made between these regions for overall prevalence values, mode of transmission and individual lesion presentation (candidiasis, oral hairy leukoplakia, periodontal disease, Kaposi's sarcoma, salivary gland disease, oral ulcers and other lesions). Apparent differences exist between the reported prevalence values of oral candidiasis, periodontal disease, Kaposi's sarcoma and tuberculous ulcers, the significance of which is uncertain. There is a need to standardise research methodologies. This would enable appropriate comparisons to be made and a better understanding of the implications of the oral HIV disease process in South Africa and elsewhere on the continent.

AIDS-Related Opportunistic Infections↗
PubMed1998

Serotyping of HIV type 1 infections: definition, relationship to viral genetic subtypes, and assay evaluation. UNAIDS Network for HIV-1 Isolation and Characterization.

V3 serotyping refers to a system based on binding of antibody in patient sera to V3-loop peptides derived from HIV-1 env genetic subtypes. The V3x serotype represents reactivity of serum from an HIV-1-infected patient (regardless of viral genetic subtype), which reacts preferentially to a V3 peptide derived from the X subtype sequence. We have classified HIV-1 serotypes, determined the relationship between the HIV-1 V3 serotypes and viral genetic subtypes in a large study (n = 125), and evaluated the performance of three different V3 peptide-binding assays. Seven HIV-1 V3 serotypes were identified: A, B, B-Br, B-Th, C, D, and E. Serotypes B-Br and B-Th represent sera that react specifically to peptides derived from Brazilian B (B-Br, GWGR) and Thai B (B-Th, GPGQ) strains. The HIV-1 V3 B, C, and E serotypes correlated closely with their viral env genetic subtypes; 19-26 of 32 B sera (59-79%), 3-4 of 4 C sera (75-100%), and 19-22 of 23 E sera (83-96%) were identified as serotypes B, C, and E, respectively. In contrast, two major V3 serotypes were classified in A sera: A (14-18 of 36 [40-50%]) and C (12-19 of 36 [33-54%]). Similarly, two major V3 serotypes were classified in D sera: B (6-10 of 20 [30-50%]) and D (9-12 of 20 [45-60%]). Serotyping of subtype E sera showed the best concordance with genetic subtypes by all assays. Overall, HIV-1 V3 serotyping produced consistent results among three laboratories. However, HIV-1 V3 serotypes do not distinguish all HIV-1 genetic subtypes. The relative biological significance of the V3 serotypes remains to be elucidated.

Amino Acid Sequence↗
PubMed1998

Evaluation of the MycoAKT latex agglutination test for rapid diagnosis of Mycobacterium avium complex infections.

Rapid diagnosis of Mycobacterium avium complex (MAC) bacteremia is important for management of patients with the acquired immunodeficiency syndrome who have disseminated MAC. The purpose of this study was to determine the reliability of the MycoAKT latex agglutination test for direct detection of MAC in positive mycobacterial blood cultures. First, colonies of isolates of previously identified mycobacteria, including 35 MAC, were tested. Of the 55 isolates evaluated, 33 were identified as MAC by the latex test, including 31 of the known MAC and 2 M. chelonae (sensitivity, 88.6%; specificity, 90.0%). Second, broth from 20 ESP II and 20 BACTEC 12B bottles seeded with isolates of MAC were tested. Aliquots from 19 (95%) ESP II cultures and 16 (80%) 12B cultures were positive by the latex test. In phase 3, broth from 115 signal-positive ESP II blood cultures were tested by latex agglutination. Forty-three subcultures from these bottles grew mycobacteria (41 MAC and 2 Mycobacterium tuberculosis complex); the remainder grew no organisms. Broth from 40 of the blood cultures (39 that grew MAC and 1 from which no organisms were recovered) were latex positive; thus, the sensitivity, specificity, and positive and negative predictive values of the latex test for direct identification of MAC in ESP II blood cultures were 95.1, 98.6, 97.5, and 97.3%, respectively. The mean time to detection of MAC was 14.6 days (range, 6-34 days) with the direct latex test, compared with 18.3 days (range, 9-36 days) with subculture and probe (p < 0.05).

AIDS-Related Opportunistic Infections↗
PubMed1998

Older adults and the news media: utilization, opinions, and preferred reference terms.

We surveyed 868 community-dwelling older adults about their (a) utilization of media news, (b) opinion of news media coverage of older people, and (c) preferences among terms used by news media to refer to senior citizens. Those with more than high school education read more newspaper news than those with less education. All groups watched TV news more frequently than they read the newspaper. Respondents had reservations about the news media's accuracy in, attitude toward, and interest in stories regarding seniors. Clear education and gender-related patterns emerged, whereas age proved nonsignificant in many analyses. Respondents' preferred reference terms were: (nouns) senior citizen, retiree, senior, and older adult; (adjectives) retired, senior, and mature. Respondents disliked: (nouns) old man/woman, old person, oldster, old timer, and geezer; (adjectives) old, aged, gray, and geriatric.

Aged↗