Applying biofluid 1H NMR-based metabonomic techniques to distinguish between HIV-1 positive/AIDS patients on antiretroviral treatment and HIV-1 negative individuals.

Metabonomics, the study of metabolites and their role in various physiological states, is a novel methodology arising from the post-genomics era and has extensive biomedical application. This technology has exhibited vast success in the identification and study of human diseases and may find further application in the study of HIV/AIDS. Specifically, the wide range of clinical and metabolic abnormalities associated with the use of antiretroviral (ARV) treatment may be investigated. To this end, this preliminary study evaluated whether metabonomic techniques could distinguish between HIV-1 positive/AIDS patients utilizing antiretroviral therapy and HIV-1 negative individuals. Serum metabolic profiles determined by 1H nuclear magnetic resonance (NMR) spectroscopy combined with pattern recognition analysis of the data showed that this distinction was attainable; suggesting that ARV-associated side-effects could be monitored utilizing NMR metabonomic techniques.

Mechanism of inhibition of cytochrome P450 C21 enzyme activity by autoantibodies from patients with Addison's disease.

OBJECTIVE: To study possible mechanisms for the inhibition of cytochrome P450 C21 (steroid 21-hydroxylase) enzyme activity by P450 C21 autoantibodies (Abs) in vitro. DESIGN: Two possible mechanisms for the inhibition of P450 C21 enzyme activity by P450 C21 Abs were studied: (a) conformational changes in the P450 C21 molecule induced by Ab binding and (b) the effects of Ab binding to P450 C21 on the electron transfer from the nicotinamide adenine dinucleotide phosphate reduced (NADPH) cytochrome P450 reductase (CPR) to P450 C21. METHODS: The effect of P450 C21 Ab binding on the conformation of recombinant P450 C21 in yeast microsomes was studied using an analysis of the dithionite-reduced CO difference spectra. The effect of P450 C21 Abs on electron transfer was assessed by analysis of reduction of P450 C21 in the microsomes in the presence of CO after addition of NADPH. RESULTS: Our studies confirmed the inhibiting effect of P450 C21 Abs on P450 C21 enzyme activity. Binding of the Abs did not induce significant change in the P450 C21 peak at 450nm (native form) and did not produce a detectable peak at 420 nm (denatured form) in the dithionite-reduced CO difference spectra. This indicated that conformation of P450 C21 around the heme was not altered compared with the native structure. However, incubation of the P450 C21 in yeast microsomes with P450 C21 Ab inhibited the fast phase electron transfer from the CPR to P450 C21. CONCLUSIONS: Our observations suggested that the mechanism by which P450 C21 Abs inhibit P450 C21 enzyme activity most likely involves inhibition of the interaction between the CPR and P450 C21.

Peptide immunogens based on the envelope region of HIV-1 are recognized by HIV/AIDS patient polyclonal antibodies and induce strong humoral immune responses in mice and rabbits.

Peptide immunogens produced by novel synthesis techniques and based on envelope proteins have repeatedly proven successful in inducing anti-HIV and anti-SIV responses in addition to producing anti-peptide immunity [Vaccine 12 (8) (1994) 736; AIDS Res. Hum. Retroviruses 14 (9) (1998) 751; Vaccine (2002) 2680]. We report here the design and evaluation of synthetic peptide constructs mimicking the variability of the third variable (V3) loop, or representing the conservation of the CD4 region of HIV-1 envelope. Three peptides based on the V3 region of HIV-1 subtype C gp120 and designated multiple epitope immunogens (MEI) differ in that one was randomly branched containing a spacer (b-MEI-s), another conjugated to a tetrameric lysine core (MEIV3b(4)) and the third conjugated to poly-L-lysine (poly-L-MEI). The method of synthesis employed produced peptides that were either linear, dimeric or tetramerically branched thereby providing differing levels of conformation. In addition the peptides also differed in their levels of variability. A fourth peptide designated B138 was based on a conserved region of HIV-1 envelope. The aim of this work was to evaluate the effect of variability and level of conformation on the immunogenicity of variable region peptides (MEI's) when compared to that of a known immunogenic and conserved region peptide (B138). Anti-peptide humoral immunity induced in BALB/c mice and New Zealand White rabbits produced antigen-recognizing antibody titres of

Hospital admission for acute stroke: who, for how long, and to what effect?

Data from 976 patients registered in a community survey as suffering an acute stroke have been analysed to discover what factors are associated with admission to hospital, how long patients spend in hospital, and whether there are any specific benefits attributable to hospital admission. Six hundred and twenty-five patients were admitted on account of their index stroke. These patients were compared with the 249 who remained at home throughout the first six months after the stroke--the remaining patients were admitted for other reasons or had their stroke in hospital. Two major factors related to an increased chance of admission: having a more severe disability and not having a carer. The same factors were associated with a longer length of stay for those who returned home within six months. Nevertheless 26% of patients managed at home were severely disabled when first seen within seven days. Patients admitted had a median stay of seven days if they died, 19 days if they returned home, and 149 days if they needed alternative long-term accommodation. Patients from the study population of 215 000 people occupied an average of 11.4 beds/100 000 over the first six months after their stroke. After making allowance for the increased severity of disability seen in those admitted to hospital, no differences in functional, social or emotional outcome were found for either place of care.

Services for stroke patients one year after stroke.

The use of community services by stroke patients was investigated one year after their stroke. Survivors from a register of all patients from a defined community were followed up one year after their stroke. Four hundred and thirty six of the 492 survivors were seen: 301 lived at home with someone, 82 lived at home alone, and 53 were in long-stay care. One hundred and forty seven (38%) of those at home were visited by one or more community services, the major ones being district nurse (73), home help (73), day centres (42), and meals on wheels (30). Analysis suggests that these services reach the patients who need most help. However, some 57 (19%) disabled patients are being looked after at home without any outside help.

Driving after a stroke.

Four hundred and thirty-eight stroke patients from a community register covering a period of 28 months were interviewed at one year post-stroke. Of 144 (34%) living at home who had been driving prior to their stroke, 82 (58%) did not resume post-stroke. Assessments of arm function, walking, functional ability and IQ showed ex-drivers to be significantly more disabled than drivers. Stopping driving was associated with a loss of social activities and with a higher frequency of depression amongst ex-drivers when compared with drivers. This was despite 79% of ex-drivers having easy access to alternative car transport. Extending mobility allowance to the 49 (60%) ex-drivers over 65 years old at the time of their stroke might ease their situation. More appropriate assessments would be needed to establish whether ex-drivers would benefit from retraining or car adaptations to enable them to return to driving.

Peptide immunogens designed to enhance immune responses against human immunodeficiency virus (HIV) mutant strains: a plausible means of preventing viral persistence.

A major problem impeding the development of an effective HIV-1 vaccine is the rapid antigenic variability that occurs throughout the viral genome but is most pronounced in the envelope (env) gene and env gene products. The high number of errors made by the reverse transcriptase (RT) enzyme and the absence of an RT proofreading mechanism during HIV-1 replication leads to new antigenic variants that escape current immunological attack. In turn, accumulation of escape mutants leads to a persistent infection. It has been hypothesized through many means including mathematical modeling that preventing HIV persistence necessitates a vaccine that enhances immunity against a sufficiently large fraction of mutant stains. To this extent we have developed a 4 branched--and an 8 branched--multiple epitope immunogen (MEI) that in theory represent 6.7x10(7) and 1.8x10(16) envelope V3 loop sequences respectively. Both MEI constructs were recognized by antibodies in sera from AIDS and/or HIV-1 positive patients from South Africa and Puerto Rico. The immunogens also induced immune responses in MF1 mice and New Zealand White rabbits with the octameric MEI proving to be a more effective antigen. This data supports our hypothesis that synthetic peptides designed to represent the variable regions of HIV-1 envelope should induce immunity against a large quantity of mutant strains.

Evaluation of a synthetic vaccine construct as antigen for the detection of HIV-induced humoral responses.

Synthetic V3 loop peptides hold numerous benefits for the development of HIV vaccines and in immunodiagnosis; however, their use is limited due to the extensive antigenic variability of this region. The effectiveness of a potential HIV vaccine component, which accounts for V3 loop variability, is evaluated here. A branched peptide construct representing multiple sequences and allowing 1.8 x 10(16) possible permutations was developed to mimic circulating HIV-1 subtype C, V3 loops. The construct was found to be immunogenic, able to induce neutralizing antibodies and sensitive to HIV-1 subtype B/C and HIV-2. This alternative antigen format also incorporates conformational epitopes.

Multiple sclerosis--management and rehabilitation.

After reviewing the size of the problem of multiple sclerosis, and the likely case-load for doctors in different settings, this paper than proceeds to consider the major challenges in management and rehabilitation for this disease. The latter resolve themselves into what to discuss with the patient; relapses and their prevention, including general advice on such matters as stress, pregnancy, and infection; major problems including bladder and bowel dysfunction, sexual difficulties, spasticity, ataxia and incoordination, vision, and intellectual and psychological manifestations, and other problems, such as menstruation, obesity, and pressure sores. The paper concludes with a discussion of the role of specialist physicians.

Study of fatal cases of Friedreich's ataxia.

A study of 82 fatal cases of Friedreich's ataxia showed that over half the patients died of heart failure while nearly three-quarters had evidence of cardiac dysfunction during life. A high incidence of diabetes mellitus (23%) was another finding, and four patients developed diabetic ketosis terminally.

Producing a highly immunogenic synthetic vaccine construct active against HIV-1 subtype C.

A synthetic peptide immunogen designated the multiple epitope immunogen (MEI), based on the principle neutralizing domain (PND) of the third variable region (V3) of the HIV-1 subtype C surface envelope protein was prepared by combining two different modes of synthesis [Vaccine 12 (8) (1994) 736; AIDS Res. Hum. Retroviruses 14 (9) (1998) 751; J. Biol. Chem. 263 (4) (1988) 1719]. The MEI induced strong humoral immune responses (titers of >100) in Swiss White and Balb/c mice and antibodies from individuals with HIV/AIDS recognize the immunogen at similar antibody titers. Anti-MEI antibodies were detected by ELISA (using HIV-1 and the immunogen as antigen) and confirmed by proliferation assays (stimulation indices of >5).

Hand contractures in Parkinson's disease.

Three cases of hand contractures due to Parkinson's disease and possible mechanisms that may be involved in their pathogenesis are described.