Facilitators and barriers to TB care during the COVID-19 pandemic

BACKGROUND

Knowledge about factors influencing access and adherence to TB care, and on the impact of the COVID-19 pandemic on TB care in resource-restricted settings is scarce. We conducted this study in Atsimo-Andrefana, a rural region in southern Madagascar where TB prevalence, poverty and food insecurity rates are high. We aimed to determine facilitators and barriers to access to and provision of TB care in rural Madagascar during the COVID-19 pandemic.

METHODS

We conducted qualitative focus group discussions (FGDs) and in-depth interviews (IDIs) with patients with TB, community health workers, facility-based health workers, public health officials and non-governmental organisation staff. We analysed interviews using thematic analysis.

RESULTS

We conducted 11 FGDs and 23 IDIs. We identified three main barriers to access and adherence to TB care: 1) stigma, 2) indirect treatment costs, and 3) food insecurity. The facilitator perceived as most influential was high health worker motivation. The effects of the COVID-19 pandemic on TB care varied between stake-holders; some health workers described delays in TB diagnosis and increased workload.

CONCLUSIONS

To improve access and adherence to TB care, both indirect treatment costs and stigma need to be reduced; undernourished patients with TB should receive food support.

Phenotypic prediction based on metabolomic data for growing pigs from three main European breeds

Predicting phenotypes is a statistical and biotechnical challenge, both in medicine (predicting an illness) and animal breeding (predicting the carcass economical value on a young living animal). High-throughput fine phenotyping is possible using metabolomics, which describes the global metabolic status of an individual, and is the closest to the terminal phenotype. The purpose of this work was to quantify the prediction power of metabolomic profiles for commonly used production phenotypes from a single blood sample from growing pigs. Several statistical approaches were investigated and compared on the basis of cross validation: raw data vs. signal preprocessing (wavelet transformation), with a single-feature selection method. The best results in terms of prediction accuracy were obtained when data were preprocessed using wavelet transformations on the Daubechies basis. The phenotypes related to meat quality were not well predicted because the blood sample was taken some time before slaughter, and slaughter is known to have a strong influence on these traits. By contrast, phenotypes of potential economic interest (e.g., lean meat percentage and ADFI) were well predicted (R(2) = 0.7; P < 0.0001) using metabolomic data.

Soft tissue tumours and mass-like lesions of the chest wall: a pictorial review of CT and MR findings

Soft tissue tumours and tumour-like lesions of the chest wall are uncommon. The purpose of this pictorial essay is to describe the imaging findings of chest wall soft tissue tumours and tumour-like lesions. We searched the radiological and pathological archive at our institution retrospectively and reviewed the literature on soft tissue tumours of the chest wall. Common chest wall soft tissue tumours and mass-like lesions include peripheral nerve tumours, lipomas, liposarcomas, haemangiomas, elastofibromas, metastases, lymphoma and abscesses. Other lesions encountered include desmoid tumours and malignant fibrous histiocytoma. Many have distinctive radiological findings or occur in specific locations, allowing a specific radiological diagnosis to be suggested.

[Personality disorders in an institution for ambulatory mental health care. Prevalence, type and severity, treatment indication and drop out]

BACKGROUND

Personality disorders occur frequently. The presence of one or more personality disorders can influence the severity of the symptoms and can affect coping, treatment indication and drop out.

AIM

To study the prevalence of personality disorders in an ambulatory health care centre and to investigate the influence of both the severity and the nature of personality disorders on the following: symptomatology, interpersonal behaviour, coping and defence mechanisms, personality traits, treatment indication and drop out.

METHOD

We studied the prevalence of personality disorders in 100 patients using the International Personality Disorder Examination (IPDE), a semi-structured interview. Symptoms, interpersonal behaviour, coping and defence mechanisms and personality traits were assessed by means of self-reports. Patients were assigned to specific types of treatment by their own doctors, who were not aware of the assessment results. results Most of the patients suffered from a personality disorder. Patients with cluster-A-type personality disorders were all assigned to treatment. The majority of patients with cluster- B-type personality disorders were assigned to Axis-ii-type treatment but most patients with cluster-A-and cluster-C personality disorders were assigned to Axis-I-type treatment. The dropout percentage was higher among patients with a personality disorder than among those without. Among patients with personality disorders the drop-out percentage was highest in those from the A and C clusters. Patients with personality pathology from the A cluster were 13 times more likely to drop out than those without A cluster pathology, patients with C cluster pathology were 11 times more likely to drop out than those without C cluster pathology.

CONCLUSION

In ambulatory mental health care more attention needs to be given to the diagnosis of personality disorders. Results suggest that in the treatment of patients with A and C cluster pathology much effort must be directed at fostering therapeutic alliance and compliance to treatment.

Schizophrenia as an inflammation-mediated dysbalance of glutamatergic neurotransmission

This overview tries to bridge the gap between psychoneuroimmunological findings and recent results from pharmacological, neurochemical and genetic studies in schizophrenia. Schizophrenia is a disorder of dopaminergic neurotransmission, but modulation of the dopaminergic system by glutamatergic neurotransmission seems to play a key role. This view is supported by genetic findings of the neuregulin- and dysbindin genes, which have functional impact on the glutamatergic system. Glutamatergic hypofunction, however, is mediated by the N-methyl-D-aspartate (NMDA)-receptor antagonism. The only endogenous NMDA receptor antagonist identified up to now is kynurenic acid (KYNA). Despite the NMDA receptor antagonism, KYNA also blocks, in lower doses, the nicotinergic acetycholine receptor, i.e., increased KYNA levels can explain psychotic symptoms and cognitive deterioration. KYNA levels are described to be higher in the cerebrospinal fluid (CSF) and in critical central nervous system (CNS) regions of schizophrenics as compared to controls. Another line of evidence suggests that a (prenatal) infection is involved in the pathogenesis of schizophrenia. Due to an early sensitization process of the immune system or to a (chronic) infection, which is not cleared through the immune response, an immune imbalance between the type-1 and the type-2 immune responses takes place in schizophrenia. The type-1 response is partially inhibited, while the type-2 response is over-activated. This immune constellation is associated with inhibition of the enzyme indoleamine dioxygenase (IDO), because IDO - located in astrocytes and microglial cells - is inhibited by type-2 cytokines. IDO catalyzes the first step in tryptophan metabolism, the degradation from tryptophan to kynurenine, as does tryptophan 2,3-dioxygenase (TDO). Due to the inhibition of IDO, tryptophan-kynurenine is predominantly metabolized by TDO, which is located in astrocytes, not in microglial or other CNS cells. In schizophrenia, astrocytes in particular are activated, as increased levels of S100B appear. Additionally, they do not have the enzymatic equipment for the normal metabolism-route of tryptophan. Due to the lack of kynurenine hydroxylase (KYN-OHase) in astrocytes, KYNA accumulates in the CNS, while the metabolic pathway in microglial cells is blocked. Accordingly, an increase of TDO activity has been observed in critical CNS regions of schizophrenics. These mechanisms result in an accumulation of KYNA in critical CNS regions. Thus, the immune-mediated glutamatergic-dopaminergic dysregulation may lead to the clinical symptoms of schizophrenia. Therapeutic consequences, e.g., the use of anti-inflammatory cyclo-oxygenase-2 inhibitors, which can also decrease KYNA directly, are discussed.

Induction of UGT1A6 isoform by inflammatory conditions in rat astrocytes

Alteration of drug metabolism under diseased conditions is of clinical importance. We have investigated the effects of inflammatory conditions on phase II drug-metabolizing enzyme activity in rat cultured astrocytes. Lipopolysaccharide (LPS) treatment was used to promote inflammatory conditions. Thus, we reported that LPS initiates an inflammatory response, which is mediated by pro-inflammatory mediators and free radical generation. An increase in astrocyte glucuronidation activity was observed after a 48-h LPS treatment. This increase in glucuronidation activity was associated with an up-regulation of the UGT1A6 isoform mRNA level as shown by RT-PCR and gene reporter assay. Moreover, this endotoxin-induced increase in UGT1A6 expression level was blocked by actinomycin D and cycloheximide, indicating the requirement for RNA and protein synthesis. The UGT1A6 expression enhancement could be prevented by anti-inflammatory drugs (dexamethasone and NS398) or nitric oxide synthase inhibitors (L-NAME and L-NMMA). Moreover, gel shift assay revealed increased activator protein-1 (AP-1) binding activity after LPS treatment. We propose, based on the data presented, that the action of LPS to induce UGT1A6 isoform up-regulation may be mediated by pro-inflammatory mediator accumulation, and AP-1 binding activity increase.

Psychological and/or educational interventions for the prevention of depression in children and adolescents

BACKGROUND

Depression is the fourth most important disease in the estimation of the burden of disease Murray 1996 and is a common problem with prevalence rates estimated to be as high as 8% in young people. Depression in young people is associated with poor academic performance, social dysfunction, substance abuse, suicide attempts, and completed suicide (NHMRC 1997). This has precipitated the development of programmes aimed at preventing the onset of depression. This review evaluates evidence for the effectiveness of these prevention programmes.

OBJECTIVES

To determine whether psychological and/or educational interventions (both universal and targeted) are effective in reducing risk of depressive disorder by reducing depressive symptoms immediately after intervention or by preventing the onset of depressive disorder in children and adolescents over the next one to three years.

SEARCH STRATEGY

The Cochrane Depression, Anxiety and Neurosis Group trials register (August 2002), MEDLINE (1966 to December Week 3 2002), EMBASE (1980 to January Week 2 2003), PsychInfo (1886 to January Week 2 2003) and ERIC (1985 to December 2002) were searched. In addition, conference abstracts, the reference lists of included studies, and other reviews were searched and experts in the field were contacted.

SELECTION CRITERIA

Each identified study was assessed for possible inclusion by two independent reviewers based on the methods sections. The determinants for inclusion were that the trial include a psychological and/or educational prevention programme for young people aged 5 to 19 years-old, who did not meet DSM or ICD criteria for depression and/or did not fall into the clinical range on standardised, validated, and reliable rating scales of depression.

DATA COLLECTION AND ANALYSIS

The methodological quality of the included trials was assessed by two independent reviewers according to a list of pre-determined criteria, which were based on quality ratings devised by Moncrieff and colleagues (Moncrieff 2001). Outcome data was extracted and entered into Revman 4.2. Means and standard deviations for continuous outcomes and number of events for dichotomous outcomes were extracted where available. For trials where the required data were not reported or could not be calculated, further details were requested from first authors. If no further details were provided, the trial was included in the review and described, but not included in the meta-analysis. Results were presented for each type of intervention: targeted or universal interventions; and educational or psychological interventions and if data were provided, by gender. Where possible data were combined in meta-analyses to give a treatment effect across all trials. Sensitivity analysis were conducted on studies rated as "adequate" or "high" quality, that is with a score over 22, based on the scale by Moncrieff et al (Moncrieff 2001). The presence of publication bias was assessed using funnel plots.

MAIN RESULTS

Studies were divided into those that compared intervention with an active comparison or placebo (i.e. a control condition that resembles the intervention being investigated but which lacks the elements thought to be active in preventing depression) and those that used a "wait-list" or no intervention comparison group. Only two studies fell into the former category and neither showed effectiveness although one study was inadequately powered to show a difference and in the other the "placebo" contained active therapeutic elements, reducing the ability to demonstrate a difference from intervention. Psychological interventions were effective compared with non-intervention immediately after the programmes were delivered with a significant reduction in scores on depression rating scales for targeted (standardised mean difference (SMD) of -0.26 and a 95% confidence interval (CI) of -0.40 to -0.13 ) but not universal interventions (SMD -0.21, 95% CI -0.48, 0.06), with a significant effect maintained on pooling data (SMD -0.26, 95% CI -0.36, -0.15). While small effect sizes were reported, these were associated with a significant reduction in depressive episodes. The overall risk difference after intervention translates to "numbers needed to treat" (NNT) of 10. The most effective study is the targeted programme by Clarke (Clarke 2001) where the initial effect size of -0.46 is associated with an initial risk difference of -0.22 and NNT 5. There was no evidence of effectiveness for educational interventions. Reports of effectiveness for boys and girls were contradictory. The quality of many studies was poor, and only two studies made allocation concealment explicit. Sensitivity analysis of only high quality studies did not alter the results significantly. The only analysis in which there was significant statistical heterogeneity was the sub-group analysis by gender where there was variability in the response to different programmes for both girls and boys. For the most part funnel plots indicate findings are robust for short term effects with no publication bias evident. There are too few studies to comment on whether there is publication bias for studies reporting long-term (12-36 month) follow-up.

REVIEWER'S CONCLUSIONS

Although there is insufficient evidence to warrant the introduction of depression prevention programmes currently, results to date indicate that further study would be worthwhile. There is a need to compare interventions with a placebo or some sort of active comparison so that study participants do not know whether they are in the intervention group or not, to investigate the impact of booster sessions to see if effectiveness immediately after intervention can be prolonged, ideally for a year or longer, and to consider practical implementation of prevention programmes when choosing target populations. Until now most studies have focussed on psychological interventions. The potential effectiveness of educational interventions has not been fully investigated. Given the gender differences in prevalence, and the change in these that occurs in adolescence with a disproportionate increase in prevalence rates for girls, it is likely that girls and boys will respond differently to interventions. Although differences have been reported in studies in this review the findings are contradictory and a more definitive delineation of gender specific responses to interventions would be helpful.

Urinary health in eldercare environments: an update from the NAFC

The National Association For Continence elected to cancel its 2001 conference scheduled for October 2001 in Washington, DC in light of national events. Executive Director Nancy Muller has provided Ostomy/Wound Management with a synopsis of key issues, important considerations, and the syllabus. We are grateful for the opportunity to serve as a forum for this worthy organization.

Infant and adolescent hepatitis B immunization up to 1999: a global overview

This article presents a global overview of hepatitis B infant and adolescent immunization programmes. The 108 reported universal infant or adolescent immunization programmes and 87 reported national infant coverage rates fit a pattern, explained by hepatitis B endemicity, prosperity, policy emphasis, and immunization programme strength. Most East and Southeast Asian, Pacific, and Middle Eastern countries have intermediate to highly endemic hepatitis B. Most have achieved 65-100% coverage. South and Central Asia and sub-Saharan Africa have intermediate to high endemicity, with some countries having hepatitis B immunization programmes. Some Southern and Eastern European countries, with intermediate endemicity, have high coverage. Low endemic Northern European countries vaccinate higher risk groups; some have universal infant or adolescent programmes. Caribbean and Latin American countries have varying endemicity, and most started programmes. Low endemic North American countries have universal vaccination programmes. Universal immunization strategies have greatly reduced incidence and prevalence, and are cost-effective for many countries, but many have difficulties affording this vaccine. Globally, most infants are not being immunized against hepatitis B virus infection. Increasing coverage, and decreasing the numbers of people diseased and dying from this virus, may require delivering heat-stable vaccine beyond cold chains, creative financing to reduce prices, and multivalent vaccines.

Topoisomerase I-mediated antiproliferative activity of enantiomerically pure fluorinated homocamptothecins

Homocamptothecin (hCPT) is an E-ring modified camptothecin (CPT) analogue bearing a methylene spacer between the alcohol and carboxyl functions of the CPT lactone. Combining pronounced inhibitory activity of topoisomerase I (Topo I) with enhanced plasma stability, hCPT constitutes an attractive template for the elaboration of new anticancer agents. Fluorinated hCPT analogues, prepared in enantiomerically pure form, were assayed by their stimulation of Topo I-mediated DNA cleavage. Translation into cytotoxicity against tumor cells was evaluated on HT29 human colon adenocarcinoma and on the multidrug resistant lung and bladder tumor cell lines, A549 and T24r. Good correlation is observed between the ability of the drugs to stimulate Topo I-mediated DNA cleavage and the respective 50% inhibitory concentrations (IC(50) values) of the HT29, A549, and T24r cell growth. Fluorine substitution in the A-ring of hCPT was found to have a pronounced influence on biological activity, providing several compounds which are up to 100-fold more potent than CPT in terms of IC(50). Among these, 10,11-difluoro-hCPT has been selected for further development.

Nephrotic syndrome in Namibian children

BACKGROUND AND OBJECTIVES

Patterns of nephrotic syndrome vary between regions and countries, and influence approaches to management. In the mid-1970s the University of Stellenbosch became involved in providing tertiary care to Namibia, including a paediatric nephrology service. The aim of this study was to document the clinical, pathological and outcome features of nephrotic syndrome in Namibian children.

SUBJECTS

Seventy black Namibian children with nephrotic syndrome were managed from 1975 to 1988. Sixty-eight renal specimens (67 biopsies and 1 autopsy specimen) were evaluated.

RESULTS

Twenty-nine of the 70 children (41.4%) were hepatitis B virus (HBV) carriers, of whom 25 (86.2%) were male. Of the 29, 26 had predominantly membranous glomerulonephritis (MGN), 1 mesangiocapillary glomerulonephritis (MCGN), and 1 focal segmental glomerulosclerosis (FSGS); 1 child in advanced renal failure was not biopsied. Five children (7.4%) showed minimal change disease (MCD), 11 (16.2%) FSGS and 15 (22.1%) diffuse mesangial proliferative glomerulonephritis (DMP). The remaining 10 children showed diffuse glomerulosclerosis (6), MCGN (3) and endocapillary proliferative GN (1). Four of the 5 children with MCD went into remission on immunosuppressive treatment. Of the 15 with DMP, 4 improved spontaneously and only 1 of those treated did not improve. Only 2 of those with FSGS improved on treatment. The children with HBV-associated MGN and MCGN were offered symptomatic rather than specific treatment. Thirteen children presented with degrees of chronic renal failure. Eight are known to have died, 3 of relentless nephrotic syndrome and 4 (of whom 3 were HBV carriers) of end-stage renal failure. One child died of penicillin anaphylaxis.

CONCLUSIONS

The pattern of nephrotic syndrome in black Namibian children differed greatly from the non-African pattern elsewhere in that MCD was uncommon and HBV-associated GN was the most common single group. The most frequent pattern of HBV-associated GN was MGN with some mesangiocapillary features showing marked male predominance. MCD and DMP were potentially treatable and could only be identified by biopsy. HBV carrier rates exert a major influence on the proportions of morphological subgroups of nephrotic syndrome in children. As these HBV carrier rates alter in future due to the influence of vaccination and urbanisation, the relative size of nephrotic subgroups seems likely to alter.

Efficient simulation of coherence transfer pathway selection by phase cycling and pulsed field gradients in NMR

The selection of well-defined coherence transfer pathways is an essential feature of all but the simplest NMR and EPR pulse sequences. This selection can be achieved by phase cycling and by pulsed field gradients. The properties of the RF-pulses (flip angle, offset effects, inhomogeneity) and transport phenomena (diffusion, flow) in conjunction with gradients cause a weighting of the different coherence transfer pathways. We present a method by which the selection process can be simulated efficiently and visualized easily. In its basic form it involves straightforward matrix manipulations without reference to the density matrix and the particular spin system. This method is implemented in a MATLAB program, called CCCP (Complete Calculation of Coherence Pathways). Copyright 1998 Academic Press.

The glycyl radical enzyme TdcE can replace pyruvate formate-lyase in glucose fermentation

Mutants of Escherichia coli unable to synthesize a functional pyruvate formate-lyase (PFL) are severely impaired in their capacity to grow by glucose fermentation. In a functional complementation assay designed to isolate the pfl gene from Clostridium butyricum, we fortuitously identified a gene that did not encode a PFL but nonetheless was able to complement the phenotypic defects caused by an E. coli pfl mutation. The clostridial gene encoded a basic 14. 5-kDa protein (TcbC) which, based on amino acid similarity and analysis of immediately adjacent DNA sequences, was part of a transposase exhibiting extensive similarity to the product of the site-specific transposon Tn554 from Staphylococcus aureus. Our studies revealed that the clostridial TcbC protein activated the transcription of the E. coli tdcABCDEFG operon, which encodes an anaerobic L-threonine-degradative pathway. Normally, anaerobic synthesis of the pathway is optimal when E. coli grows in the absence of catabolite-repressing sugars and in the presence of L-threonine. Although anaerobic control of pathway synthesis was maintained, TcbC alleviated glucose repression. One of the products encoded by the tdc operon, TdcE, has recently been shown to be a 2-keto acid formate-lyase (C. Hesslinger, S. A. Fairhurst, and G. Sawers, Mol. Microbiol. 27:477-492, 1998) that can accept pyruvate as an enzyme substrate. Here we show that TdcE is directly responsible for the restoration of fermentative growth to pfl mutants.

Internal rotation of mutually interacting methyl groups: A 13C NMR study

The overall and intramolecular rotational diffusion behavior of 1,3, 7,10-tetramethylbenzo[c]cinnoline was determined from longitudinal 13C NMR relaxation and 1H-13C NOE measurements in dilute chloroform solution. The four methyl groups in this compound represent three different situations of sterical hindrance. One pair of methyl groups is in close mutual sterical contact, forming the ends of an open six-membered ring. Assuming completely anisotropic overall molecular tumbling combined with a 120 degrees jump model for the internal methyl rotations the jump rates of methyl groups were evaluated and compared to earlier results on different sterically hindered compounds, in particular with respect to a potential cogwheel-like intermethyl interaction. To characterize intermethyl interactions in different sterical situations, a new gauge-the "methyl interaction volume"-is introduced. Implications for correlated rotational diffusion of methyl groups are discussed. Copyright 1997 Academic Press. Copyright 1997Academic Press

Giardia lamblia infections in B-cell-deficient transgenic mice

In the present study, we infected B-cell (and antibody-)-deficient transgenic mice with the Giardia lamblia clone GS/M-83-H7. These animals were inhibited in intestinal anti-Giardia immunoglobulin A (IgA) production and could not resolve the parasite infection, and antigenic diversification within the respective parasite populations occurred in an unusually slow manner. These findings indicate an important immunological function of local IgA antibodies which promotes antigenic variation of the parasite and is involved in control of the parasite infection.

Pregnancy in partially remitted hepatitis B-associated membranous glomerulonephritis

Hepatitis B-associated glomerulonephritis is a relatively common cause of nephrotic syndrome in endemic areas affecting especially male children. When this disease affects girls or women, both the glomerular disease and the hepatitis B carrier state could affect subsequent pregnancies. This may be the first reported case of such a pregnancy. In this patient the partially remitted renal disease and the reduced infectivity of the hepatitis B carrier state decreased the influence of the disease on the pregnancy.

Cryptogenic organizing pneumonia. A report of 25 cases and a review of the literature

Cryptogenic organizing pneumonia (COP), also known as bronchiolitis obliterans organizing pneumonia (BOOP), is an uncommon lung disease characterized by the presence of granulation tissue within the alveolar ducts and alveoli. Because of the limited published literature on this topic and limited information on outcome we reviewed our own experience over an 8-year period and also critically evaluated the literature. We reviewed all cases of COP diagnosed from 1985 through 1992 at Vancouver General Hospital: 25 patients (14 male, 11 female) aged 20-77 years (mean, 49 yr, SD +/- 17 yr). Nine patients had myeloproliferative disorder, including 6 who had allogenic bone marrow transplants; 2 patients had connective tissue disease; and 14 patients had no underlying disease (idiopathic). Data retrieved retrospectively from clinical records included demographics, risk factors, symptoms, chest radiographs, computerized tomograms, lung function tests, therapy prescribed, and response to therapy. Symptoms included dyspnea and cough (n = 15) (60%), cough only (n = 10) (40%), and fever (n = 15) (60%). Twenty-two patients were diagnosed by open lung biopsy and 3 by transbronchial biopsy. Lung imaging showed bilateral patchy airspace consolidation or nodular opacities as the main finding in 22 patients. Pulmonary function tests showed a combined restrictive and obstructive pattern. All patients received prednisone therapy except 1 patient whose idiopathic findings resolved completely with minimal treatment. Eight patients died, including 4 of the 9 patients with myeloproliferative disorder--2 from a combination of respiratory failure due to COP and graft-versus-host disease. One of 2 patients with connective tissue disease died, and 3 of 14 patients with idiopathic COP died. COP is an uncommon condition but should be considered in patients with bilateral airspace disease, especially those who fail to respond to antibiotics for presumed pneumonia. Although pulmonary function tests and CT scan findings in conjunction with the clinical features usually suggest the diagnosis, definite confirmation usually requires either open lung biopsy or transbronchial biopsy. Histologic confirmation of the diagnosis is particularly warranted as therapy with corticosteroids is usually needed for a number of months. The prognosis is excellent with idiopathic cases but more guarded especially when COP is associated with lymphoproliferative or connective tissue disease.

HIV-associated nephropathy--an initial presentation in an HIV-positive patient

The lesions of HIV-associated nephropathy occur in patients with AIDS, AIDS-related complex and in individuals clinically asymptomatic for HIV infection. We report on a 35-year-old black South African woman who presented with nephrotic syndrome and renal failure. The renal biopsy appearance suggested HIV infection and this was subsequently verified. This finding emphasises the possibility that otherwise asymptomatic patients presenting with renal disease may be HIV-positive.

Binding sites of fluorescent probes on human serum albumin

Human serum albumin is known to have two major and selective drug binding sites, termed sites I and II. The fluorescent probes, dansylamide and dansylsarcosine selectively interact with sites I and II, respectively. However, the binding site of the fluorescent probe dansylglycine on human serum albumin is not clear from the literature. This study investigated whether dansylglycine interacts tightly with site I or II. Spectrofluorimetric titrations (quenching and complex) and circular dichroism measurements were performed to determine the binding characteristics of dansylglycine to human serum albumin. Modification in probe fluorescence was described by fluorescence titrations to be a result of competitive displacement by ligands. The pattern of displacement of this probe by several ligands whose primary binding sites are exactly known, enabled the identification of its specific binding site. The fluorescence of dansylglycine is only extensively changed when ligands of site II are added, suggesting that it strongly interacts with the benzodiazepine/indole binding site on human serum albumin.

Anti-inflammatory properties of IL-1 in carrageenan-induced paw oedema

To evaluate any inhibitory effect of a single dose of human recombinant interleukin-1 beta (hrIL-1 beta) on the severity of carrageenan-induced oedema in rats (a commonly used model of acute inflammation), we first injected 0.1 ml of carrageenan (0.2%, 0.5%, or 2%) to induce mild, moderate, or severe inflammation, respectively into the right rear footpad. Then we promptly injected the interleukin (0.02, 0.2, or 2 micrograms) subcutaneously into the flank. The initial rapid increase in volume of the injected paw (within 2 h of the subplantar injection) was independent of the dose of carrageenan, whereas the increase in volume by 6 to 10 h was dose-dependent. All doses of HrIL-1 beta inhibited the carrageenan-induced swelling at the 6th hour. In the moderate and severe carrageenan-induced oedemas, the higher dose of HrIL-1 beta induced a delayed inflammation peaking at 10 h instead at 6 h.

Representation of affinity in the case of co-operativity in protein-ligand binding

We have already proposed a "Global Association Function" to represent the global affinity of proteins to a drug; it was first applied in the case of independent binding sites. In this paper, we show that this same function can also be used to assess interactions between sites by varying the number of interacting sites and their co-operativity level. The resulting curves in two application cases are given together with the corresponding Scatchard plot: i) in a system with one single class of identical and interacting sites, ii) in a system with two classes of sites in which either primary or secondary are interacting; unexpectedly, in this latter case we also observed that sometimes positive co-operativity occasionally resulted in a concave-up Scatchard plot which is unusually admitted. In addition, as described in one example, our function is assumption free; this might be an advantage over usual methods, such as discrete parameter methods, because they require additional and empirical hypotheses on their related binding model.

Protein binding and stereoselectivity of nonsteroidal anti-inflammatory drugs

Stereoselective binding of nonsteroidal anti-inflammatory drugs (NSAIDs) can be studied using various techniques. Thus the results obtained by different investigators may be poorly consistent and even contradictory. NSAIDs are bound stereoselectively to serum albumin to different degrees depending on the drug investigated (ibuprofen, indoprofen, carprofen, etodolac, ketoprofen and flurbiprofen). For other drugs, both enantiomers are bound to a similar extent (pirprofen, fenoprofen). This stereoselectivity could vary with experimental conditions, in particular with protein concentration (ketoprofen, etodolac), leading to individual differences. Finally, the stereoselectivity of protein binding and of pharmacokinetics can be compared: differences in binding between enantiomers can explain their differences in pharmacokinetics, once metabolic properties such as inversion have been taken into account.

Direct high-performance liquid chromatographic resolution of the enantiomers of tiaprofenic acid using immobilized human serum albumin

Resolution of racemic tiaprofenic acid (TA) has been performed using immobilized human serum albumin as the stationary phase. The eluent was phosphate buffer-acetonitrile-n-octanoic acid (90:10:0.015, v/v). Detection was achieved at 305 nm. The pharmacokinetics of the enantiomers were studied following oral administration into humans and after subcutaneous injection in rats. Plasma concentrations of (+)-TA were much greater than those of (-)-TA. For the rat, the pharmacokinetic parameters between (-)-TA and (+)-TA were all statistically different (p < 0.005).

[Stereoselective protein binding of non-steroidal anti-inflammatory agents. Pharmacological implications]

Non steroidal anti-inflammatory drugs (NSAIDs) contain a chiral carbon alpha to carboxyl function. Except for naproxen, chiral NSAIDs are marketed for clinical use as racemate, ie an equimolar mixture of the two enantiomers R(-) and S(+). However, in vitro studies have shown that the anti-inflammatory activity exists almost solely in the S form. The unbound fraction is able to diffuse into tissues and to reach sites of action. It represents also the pharmacological active form. Stereoselective protein binding studies carried out at various concentrations of NSAIDs and albumin are used to evaluate the free fraction of the active enantiomer. Two optical isomers do not interact in the same manner with proteins and this binding stereoselectivity depends on NSAID and experimental conditions. Thus, it seems difficult to predict the in vivo free concentration of each enantiomer and protein binding experiments should be achieved taking into account the physiopathological parameters which influence this biological process. This enantioselectivity is determinant for the pharmacokinetic properties and could be responsible of the parameters variation obtained for each enantiomer. It could explain the variability in response to NSAIDs too. In fact, the anti-inflammatory effect is directly function of the free concentration of the S isomer. To correlate the NSAID dose with its activity, it should be better to determine this free fraction in the site of action, in particular in the synovial fluid. But the clinical response, as for example the antalgic effect, remains very far from the pharmacological activity, ie the cyclooxygenase inhibition.

Hyaluronidase degradation of hyaluronic acid from different sources: influence of the hydrolysis conditions on the production and the relative proportions of tetra- and hexasaccharide produced

1. Hyaluronic acid (HA) can be digested with a Streptomyces hyaluronidase. 2. The rate of production and the ratio of tetrasaccharide (T) and hexasaccharide (H), studied by HPLC, varied with the temperature and duration of hydrolysis. 3. The rates of production and the respective amounts of the two oligosaccharides depended on the rheological properties of the HA from different sources. 4. A close relationship was found between the initial rate of hydrolysis and the intrinsic viscosity of the HA (eta i). 5. Our data suggest that enzymatic degradation at a given pH value, temperature, and duration of hydrolysis is dependent on the conformation of HA. 6. Moreover, under given conditions, the relative proportions of the two oligosaccharides depend on the eta i and may also reflect the degree of hydrolysis of the substrate.

Pro- and anti-inflammatory properties of human recombinant IL-1 beta during experimental arthritis in rats: 2. Period-dependent effect

The systemic effects of human recombinant Interleukin-1 beta (HrIL-1 beta) on hindpaw edema were determined in arthritis induced by human native type II collagen (CII) with muramyl dipeptide (MDP) both injected on day 0. Daily treatment with HrIL-1 beta (0.2 microgram sc) pretreatment, from D-1 (the day before MDP and CII were injected) to D3 significantly delayed the secondary inflammation in the uninjected left hindpaw, whereas the same treatment from D6 to D10 at the end of the "primary" inflammation, enhanced the volume of the left hindpaw. Treatment from D13 to D17 did not affect the "secondary" edema in the left hindpaw. Thus, HrIL 1 beta administration produces pro- or anti-inflammatory effects on a developing polyarthritis depending on when treatment is started and is most effective as an anti-inflammatory molecule when started at the peak of the the inflammatory reaction, as previously described. In view of these early findings, we have compared the effect of adding HrIL-1 beta along with MDP in the sensitization procedure on the time-course of CII-induced arthritis. No adjuvant effect of HrIL-1 beta was observed. On the contrary, HrIL-1 beta significantly decreased the signs of inflammation in the injected hindpaw during the secondary inflammation. In addition, the immune response to type II collagen was less in the group receiving HrIL-1 beta, maybe because of nonspecific increase of antigen clearance. On the other hand, the MDP sensitization procedure enhanced the incidence of CII arthritis and significantly worsened the clinical parameters in both primary and secondary inflammations.

Does hydrophobic hydration destabilize protein native structures?

Water in the immediate vicinity of a non-polar solute has characteristically low entropy and high heat capacity at 25 degrees C. Common opinion has been that the insolubility of such species is caused by thermodynamic changes associated with the formation of these layers of abnormal water, 'hydrophobic hydration'. Recently, however, it has been proposed instead that hydrophobic hydration favors solution of hydrocarbons, or hydrocarbon sidechains, in water and therefore promotes protein unfolding. It is argued here that available data do not convincingly support this hypothesis.

Relation between the convergence temperatures Th* and Ts* in protein unfolding

A challenge in understanding the thermodynamics of protein unfolding is to explain the 1979 puzzle posed by Privalov. Why do values of the specific enthalpy and specific entropy of unfolding both converge to common values at approximately the same temperature (Th* approximately equal to Ts*) when extrapolated linearly versus temperature? In 1986, a liquid hydrocarbon model gave an explanation for convergence of the specific entropies at Ts*: it happens because the contribution of the hydrophobic effect to the entropy of unfolding goes to zero at Ts*. The reason for convergence of the specific enthalpies at Th* and for the equality Th* approximately equal to Ts* has remained, however, a matter for speculation; recently, some explanations have been given that are based on models for polar interactions in protein folding. We show here that the relation Th* approximately equal to Ts* can be derived straightforwardly without making any assumptions either about polar interactions or about splitting the hydrophobic interaction into two terms--one for the "hydrophobic hydration" and the other for the residual effect, as suggested recently. Thus, the liquid hydrocarbon model explains both halves of Privalov's puzzle. A similar conclusion has been reached independently by A. Doig and D. H. Williams (personal communication). It has been proposed recently that a correction should be made for the relative sizes of a hydrocarbon solute and water when computing the thermodynamic properties of the hydrophobic interaction from a solvent transfer experiment. This correction affects the temperature at which the entropy of transfer equals zero, and it is important to evaluate its effect on the convergence temperature Ts*. We show that making the size correction does not change the conclusion, reached earlier, that the liquid hydrocarbon model explains the convergence of the specific entropies of protein unfolding.

Stereoselective binding of etodolac to human serum albumin

The protein binding of etodolac enantiomers was studied in vitro by equilibrium dialysis in human serum albumin (HSA) of various concentrations varying from 1 to 40 g/liter, by addition of each enantiomer at increasing concentrations. In the 1 g/liter solution, at the lowest drug levels, the (R)-form is more bound than its antipode, the contrary being observed at the highest drug levels. For higher albumin concentrations, S was bound in a larger extent than R. Using the displacement of specific markers of HSA sites I and II, studied by spectrofluorimetry, it was suggested that R and S are both bound to site I, while only S is strongly bound to site II.

Protein binding of indomethacin in human cerebrospinal fluid

The binding of the non-steroidal anti-inflammatory drug indomethacin to proteins in human cerebrospinal fluid (CSF), drawn during lumbar puncture from 10 patients affected by lumbosciatica, was measured by equilibrium dialysis and spectrofluorimetry. Similar binding studies on human serum albumin solutions (0.5 and 1 g/L) were performed using the same techniques. The mean binding percentage of indomethacin determined by equilibrium dialysis was 40%. The results obtained by both techniques allowed us to conclude that the binding of indomethacin in CSF was essentially due to albumin.

Assay of synovial fluid hyaluronic acid using high-performance liquid chromatography of hyaluronidase digests

A high-performance liquid chromatographic method for the determination of hyaluronic acid levels in synovial fluids has been developed. The hyaluronidase sample digests, containing an internal standard (benzoic acid), were separated on a reversed-phase octadecylsilyl column eluted with 0.01 M tetrabutylammonium phosphate-acetonitrile (83:17, v/v) at pH 7.35. The determination was made on 1:10 diluted samples, by using a calibration curve from 50 to 500 micrograms/ml of human umbilical cord hyaluronic acid. For validation, the synovial fluids were simultaneously analysed by this method and a radiometric method: a high correlation was found between the two (correlation coefficient 0.94). The proposed method can be used to determine specifically the high hyaluronic acid levels of synovial fluids without interferences from other glycosaminoglycans or non-steroidal anti-inflammatory drug treatment.

Pharmacological aspects of chiral nonsteroidal anti-inflammatory drugs

Most NSAIDs are chiral molecules: they exist under 2 configurations of non-superimposable mirror images which are termed enantiomers or optical isomers or optical antipodes. Direct or indirect (resolution) methods are used to separate this equal mixture of compounds. Some of the enantiomers of the NSAIDs are able to undergo chiral inversion from the inactive R(-) to the active S(+) form. The pharmacokinetics in terms of absorption, distribution, metabolism, protein binding and elimination may be different for the 2 enantiomers, leading to interindividual variability in clinical response and drug toxicity.