Challenges for palliative care in times of COVID-19: a scoping review

Introduction

Many of the essential practices in palliative care (PC) had to be adapted to the COVID-19 pandemic. This global spread of the infectious respiratory disease, caused by SARS-CoV-2, created unprecedented obstacles. The aim of this research was to comprehensively assess the experiences and perceptions of healthcare professionals, individuals, and families in palliative and end-of-life situations during the COVID-19 pandemic.

Methods

A scoping review was conducted using the databases CINAHL Complete, MEDLINE, Scopus, SciELO, Cochrane Central Register of Controlled Trials, Psychology and Behavioral Sciences, MEDIClatina, and Portugal's Open Access Scientific Repository. The review followed the JBI® methodological approach for scoping reviews.

Results

Out of the initially identified 999 articles, 22 studies were included for analysis. The deprivation of relationships due to the safety protocols required to control the spread of COVID-19 was a universally perceived experience by healthcare professionals, individuals in PC, and their families. Social isolation, with significant psychological impact, including depersonalization and despair, was among the most frequently reported experiences by individuals in palliative situation. Despite healthcare professionals' efforts to mitigate the lack of relationships, the families of these individuals emphasized the irreplaceability of in-person bedside contact.

Systematic review registration

https://osf.io/xmpf2/.

POS0251 TRANSCRIPTOMIC CHANGES INDUCED BY MAVRILIMUMAB VERSUS TOCILIZUMAB IN EX-VIVO CULTURED ARTERIES FROM PATIENTS WITH GIANT-CELL ARTERITIS

Background

Giant cell arteritis (GCA) is a chronic disease, and affected patients suffer from relapses and glucocorticoid (GC)-related toxicity. Targeted therapies are emerging with the aim of achieving better disease control and reducing GC exposure. Blocking IL-6 receptor with tocilizumab has been a major advance in the treatment of GCA. However, approximately 40% of patients treated with tocilizumab in combination with GCs experience a flare or tocilizumab-related adverse event. Blocking GM-CSF receptor α with mavrilimumab significantly reduced risk of relapse and improved sustained remission at week 26 vs placebo in a Phase 2 trial. Not all patients satisfactorily respond to any therapy, indicating heterogeneity in leading pathogenic pathways among patients. For these reasons, it is crucial to understand the specific impact of targeted therapies on vascular lesions.

Objectives

In this study we investigated transcriptomic changes induced by tocilizumab or mavrilimumab in ex-vivo cultured arteries from patients with GCA.

Methods

Temporal artery sections obtained for diagnostic purposes from 11 patients with histopathologically-confirmed GCA and 3 controls were cultured ex-vivo and exposed to placebo, mavrilimumab, or tocilizumab (both at 20 µg/mL) for 5 days. Of 11 GCA donors, 2 had received no treatment prior to biopsy, 2 had received a single prednisone (60 mg) dose, 1 had received 2 daily doses, and the remaining 6 had extended treatment; in prednisone-treated patients, mean (SEM) treatment duration was 17.9 ±8.7 days. A separate cohort of patients (consisting of five newly diagnosed patients with GCA, age- and sex-matched with the previous cohort) was used to validate 7 transcripts by real time PCR. Genes were selected for validation based on high level of expression and differential expression with each treatment. All samples were homogenized, and total RNA was extracted with TRIzol reagent. 100 ng of RNA per sample were processed with Nanostring Inflammation gene expression assay (256 transcripts) and hybridized using nCounter Prep Station. Barcode counts from nCounter Digital Analyzer were processed with nSolver 4.0 Software. Normalised data were analyzed using R Studio 4.0.5 and IBM SPSS 22.0, and paired Wilcoxon tests were applied individually to each treatment comparison group for each analysed gene. One µg of RNA per sample from the validation cohort was retrotranscribed; subsequent real time PCRs were normalised against endogenous control GUSb and analysed using SDS 2.3 software.

Results

67 out of 250 transcripts were differentially expressed between arteries from GCA patients and arteries from control patients (all placebo-treated). Of those, only 9 transcripts remained significant after correction for multiple comparisons, with a false discovery rate ≤0.05. 81 transcripts were differentially expressed in at least one comparison across groups (Figure 1A). 15 transcripts were lower, and 6 were higher in the mavrilimumab group vs placebo; 3 transcripts were lower, and 2 were higher in the tocilizumab group vs placebo. Most changes elicited between treatments were unique, but CXCL-1 was common (Figure 1B). None remained significant after correction for multiple comparisons. The effects of mavrilimumab and tocilizumab on GNAS, CXCL1, IL8, IL2, IRF3, MRC1 and BCL6 expression by Nanostring were consistent with the effect assessed using real time PCR in the separate validation cohort (Figure 1C).

Conclusion

Mavrilimumab and tocilizumab have a different transcriptomic impact on cultured arteries from patients with GCA, with some overlapping effects, although differential effects may have been attenuated by prior GC use. A better understanding of the impact of targeted therapies on vascular inflammation is needed to improve treatment options for patients with GCA.

Acknowledgements

The authors would like to thank: the Genomics core facility of the Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and Emily Plummer, PhD, Kiniksa Pharmaceuticals, for her invaluable contribution.

The study was funded by Kiniksa Pharmaceuticals, Ltd. With support from: Fundació Clínic Barcelona, Fundació Privada Cellex, IDIBAPS, Universitat de Barcelona, Vasculitis Foundation, Marie Curie Actions, and Gobierno de España, Ministerio de Economía, Industria, y Competitividad.

Disclosure of Interests

Marc Corbera-Bellalta: None declared, Farah Kamberovic: None declared, Ferran Araujo: None declared, Roser Alba-Rovira: None declared, Georgina Espigol-Frigole Consultant of: Consulting for Janssen and Hoffmann-La Roche;, Grant/research support from: Meeting attendance support from Boehringer Ingelheim, Marco Alba: None declared, Sergio Prieto-González Speakers bureau: Lecturing for Roche, Grant/research support from: Meeting attendance support from Italfarmo and CSL Behring, José Hernández-Rodríguez Speakers bureau: Lecturing for Novartis, Consultant of: Consulting for Sobi, Grant/research support from: Meeting attendance support from Sobi and Novartis, Patricia Pérez-Galán: None declared, Kent Bondensgaard Shareholder of: Kiniksa Pharmaceuticals Corp., Employee of: Kiniksa Pharmaceuticals Corp., John F. Paolini Shareholder of: Kiniksa Pharmaceuticals Corp., Employee of: Kiniksa Pharmaceuticals Corp., Maria C. Cid Speakers bureau: Educational from GSK and Vifor, Consultant of: Consulting for Janssen, GSK, and Abbvie, Grant/research support from: Research grant from Kiniksa; meeting attendance support from Roche and Kiniksa

Cost-effectiveness of the CNIC-polypill strategy for the secondary prevention of CV disease in male and female patients with established coronary heart disease based on improved risk factor control

Background

The burden of CV disease is a health and economic challenge to societies that is expected to grow in future years due to an increased prevalence in CV risk factors. Adequate management and appropriate therapy positively modify risk factors and, consequently, improve outcomes and cost-effectiveness of care. The CNIC-polypill has demonstrated in real-life, clinical effectiveness studies, its superiority over monocomponents in improving the lipidic parameters and in reduction of blood pressure in secondary CV prevention patients.

Purpose

To assess the cost-effectiveness of the CNIC-polypill (acetylsalicylic acid 100mg, atorvastatin 20/40mg, ramipril 2.5/5/10mg) compared to usual care with individual monocomponents for the secondary prevention of CV events in patients with a history of coronary heart disease (CHD) based on control of CV risk factors.

Methods

A Markov cost-effectiveness model (1-year cycles; 4 health states: stable disease, subsequent CHD, subsequent stroke, death; payer perspective; direct medical costs; lifetime horizon; 4% discount rate) based on changes in TC (10,1% reduction), HDL-c (7.4% increment) and SBP (2.6% reduction) obtained from the NEPTUNO* – a real-life, clinical effectiveness study conducted in Spain – was set for Portugal (base case). The probability of transition between health states was based on the SMART risk equation (S0, t=10= 0.8107). Cost-effectiveness was calculated for a hypothetical population (n=1,000) that replicated the characteristics of the population in the proACS registry, comprised of Portuguese patients with previous CHD. Systematic reviews identified epidemiological, costs, utility and mortality data. Outcomes were costs (€, 2020), life years (LY) and quality adjusted LY (QALY) gained.

Results

In patients with a history of CHD, the incremental cost of the CNIC-polypill strategy reaches €365,527, while preventing 35 recurrent CHD events and 17 subsequent strokes. In women and men with previous CHD, the incremental cost reaches €392,529 and €354,444 respectively while preventing recurrent 47 and 30 CHD events and 19 and 16 subsequent strokes respectively. The ICER is €5,130/LY gained for the overall population, €5,768/LY gained for women and €4,884/LY gained for men. The ICUR is €5,332/QALY gained in total, €5,817/QALY gained for women and €5,137/QALY gained for men. Assuming a willingness-to-pay (WTP) threshold of €30,000/QALY gained, there is 76.1% chances in total, 75.8% in women and 76.9% in men for the CNIC-polypill to be cost-effective and 27.8% chances overall, 27.7% in women and 25.5% in men of it being cost saving compared to usual care.

Conclusion

The CNIC-polypill seems to be a cost-effective strategy in men and women compared to usual care with monocomponents for the secondary prevention of CV disease based on improved control of risk factors. A larger reduction in the number of recurrent events is seen in women compared to men at a slightly higher cost.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Ferrer International S.A. Base case resultsProbabilistic sensitivity analysis

Cardiovascular risk profile in Portugal: evidence from a large population-based cohort

Background

The rising prevalence of CVD in Portugal translates into more than 35 thousand annual deaths (1,2), with stroke and ischemic heart disease as the leading causes of death (3). Reducing the incidence of ASCVD is a public health priority, for which LDL-C lowering is paramount to halt atherosclerotic plaque progression (4,5). Real-world data is lacking regarding patient characterization, lipid-lowering therapy, and LDL-C levels by CV risk profile.

Purpose

To assess the proportion of patients with low, intermediate, high, and very high CV risk in a population with a complete spectrum of care, and describe their clinical characteristics, cardiovascular medications, and degree of LDL-C control.

Methods

This non-interventional, cross-sectional study included adult patients between 40 and 80 years old followed for primary or secondary CV risk prevention at a major healthcare institution that provides both primary and hospital care. Patient data spanned the period from 1/1/2008 to 31/12/2019. The index date for patient identification and characterization was 31/12/2019. CVD risk assessment was computed according to the 2019 ESC/EAS Guidelines for the management of dyslipidemias (6). Every criterion for risk assessment (excluding imaging and family history) was reconstructed using the most granular available records of clinical observations, measurements, episodes, lab orders, diagnosis and medications recorded at all primary and secondary care sites of the institution. We described patient demographic and clinical characteristics for each CV risk level, lipid-lowering treatment (LLT), and LDL-C levels.

Results

We identified 111.394 patients eligible for analysis. Sufficient records for CV risk assessment were available for 82.271 patients. According to 2019 ESC/EAS Guidelines CV risk categories, 25.7%, 21.4%, 12.2% and 40.7% of patients had low, intermediate, high and very high CV risk. High/very high CV risk patients had a mean (SD) age of 65.6 (10.1) years. Type 2 diabetes was present in 13.1% of high CV risk and 40% of very high CV risk groups. Although approximately 70% of patients with high/very high CV risk were treated with a LLT, only 5.1% of high CV risk and 3.6% of very high CV risk had LDL-C levels within the recommended targets. There was a very low use of high intensity statins or combination therapies in high/very high CV risk categories (table 1). Patients with atherosclerotic CV disease accounted for 34.6% of those at very high CV risk and only 4.8% attained desired goals (table 2).

Conclusions

There is a pressing need for better control of LDL-C levels at every stage of CV risk, with a particular focus on high and very high CV risk patients. Effective strategies for LCL-C control are thus needed.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): This study was funded by Novartis Farma, Produtos Farmacêuticos S.A.

POS1180 TREATMENT COMPLIANCE OF PATIENTS WITH RHEUMATOID ARTHRITIS DURING THE FIRST WAVE OF THE SARS-CoV-2/COVID-19 PANDEMIC IN PORTUGAL: RESULTS FROM THE COVID IN RA (COVIDRA) SURVEY

Background:

The outcomes of the infection by the SARS-CoV-2 in patients with immune-mediated inflammatory diseases were largely unknown during the early days of the COVID-19 pandemic. It was hypothesized that these patients were at higher risk of morbidity and mortality due to their inherent immune dysfunction and immunosuppressive therapy. Several rheumatology societies issued recommendations urging patients not to stop their anti-rheumatic treatments.

Objectives:

To assess treatment compliance of patients with rheumatoid arthritis (RA) during the first wave of the SARS-CoV-2/COVID-19 pandemic in Portugal.

Methods:

The web-based survey COVIDRA (COVID in RA) was developed to assess the impact of the first wave mandatory confinement in patients with RA focusing on 5 domains: RA symptoms, attitudes towards medication, employment status, physical exercise and mental health. The questionnaire was sent to RA patients through e-mail and social media of the Portuguese Society of Rheumatology and two patient associations; and it was filled locally at two rheumatology centers in Lisbon. Recruitment took place during June and July 2020. Descriptive statistics were generated by the survey software and were afterwards transported and evaluated using appropriate biostatistics software.

Results:

We obtained 441 valid questionnaires. Most respondents were female (88.4%), caucasian (93.6%), with a mean age of 58 (+/-13) years. The majority (57.6%) had longstanding disease (>10 years) and were treated with csDMARDs (63.2%) and/or bDMARDs/tsDMARDS (23,7%). Only 14% (N=61) discontinued or reduced the dosage or frequency of their RA treatment. Most of these changes were previously planned by the attending physician (27.9%). Only 11 patients (18%) discontinued their immunosuppressive medication out of fear of becoming infected with SARS-CoV-2 (corresponding to 2.5% of total responders). Another 11 patients did so because they had no prescription, couldn’t go to the community/hospital pharmacy or couldn’t afford the medication. Although these numbers preclude any statistical analysis, when compared to patients who persisted on their treatment, those discontinuing due to fear of contagion were younger (56.4 vs 58.5 years), all female (100 vs 86.8%), with long-lasting disease (≥ 11 years) (90.9% vs 57.5%), more frequently treated with bDMARDs (36.4 vs 23.1%) and presenting more symptoms of depression (54.5 vs 49.7%).

Conclusion:

Most RA patients complied with their treatment during the first wave of the SARS-CoV-2 pandemic in Portugal. Only a minority changed their immunosuppressive treatment due to fear of SARS-CoV-2 infection. Very similar rates of immunosuppressive discontinuation due to fear of contagion were reported by other authors (such as Schmeiser et al, Pineda-sic et al and Fragoulis et al).

Disclosure of Interests:

Filipe Araujo Speakers bureau: Pfizer, Biogen, Novartis, Menarini, Consultant of: MSD, Nuno Gonçalves: None declared, Ana Filipa Mourão: None declared.

Cost-effectiveness of a cardiovascular polypill strategy (aspirin, atorvastatin, ramipril) for the secondary prevention of cardiovascular disease based on real life improvement in risk factor control

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Ferrer Internacional

Background

The cardiovascular (CV) polypill has consistently demonstrated cost-effectives in decreasing the risk of CV disease in patients in secondary prevention. Previous pharmacoeconomic studies addressed improvements in adherence as a driver of health gains. This economic assessment focuses on the implications of improved control of risk factors with the polypill as observed in clinical practice.

Purpose

To assess the cost-effectiveness of a fixed-dose combination polypill (ASA 100mg, atorvastatin 20/40mg, ramipril 2.5/5/10mg) strategy for the secondary prevention of CV and cerebrovascular events in adults with a history of coronary heart disease (CHD) or stroke compared to usual care with monocomponents.

Methods

A Markov cost-effectiveness model (1-year cycles; 4 health states: stable disease, subsequent CHD, subsequent stroke, death; payer perspective; direct medical costs; lifetime horizon; 4% discount rate) based on changes in CV risk factors (total cholesterol, 18.3% reduction; high density lipoprotein cholesterol, 2.1% increment; systolic blood pressure, 11.46% reduction) obtained from a real-life effectiveness study was set for Portugal. The probability of transition between health states was based on the SMART risk equation. Cost-effectiveness was calculated for two cohorts (n = 1,000) of secondary prevention patients with previous CHD or stroke. Systematic reviews, Portuguese registries, mortality tables and official reports were searched to identify effectiveness, epidemiological, costs and utility data. Outcomes were costs (€, 2020) per life year (LY) and Quality Adjusted LY (QALY) gained. One-way (OWA) and probabilistic (PSA) sensitivity analyses tested consistency. Assumptions were validated by experts.

Results

In the CHD cohort, the incremental cost-effectiveness ratio for the polypill strategy (ICER) is 2,402 €/LY and the incremental cost-utility ratio (ICUR) is 2,328 €/QALY. Incremental cost reaches 278,927 € (polypill, 13,198,506 €; monocomponents: 12,919,579 €) with less subsequent CV events (552.31 vs 641.88) and CV deaths (102.4 vs 118.68). Assuming a willingness-to-pay (WTP) threshold of 30.000 €/QALY gained, the PSA shows a 81.4% probability for the polypill to be cost-effective and 39.1% chances to be costs saving compared to usual care. In the stroke cohort, the ICER is 386 €/LY and the ICUR is 553 €/QALY. Incremental costs are 34,178 € (polypill, 10,138,807 €; monocomponents: 10,104,629 €) with less subsequent CV events (481.99 vs 564.50) and CV deaths (101.00 vs. 117.23) with the polypill. There is a 75.9% probability for the polypill to be cost-effective and 49.5% chances to be costs saving.

Conclusion

The CV polypill is a cost-effective secondary prevention strategy compared to usual care with monocomponents. Its ICER is well below acceptable thresholds in both CV and cerebrovascular disease patients. It reduces the number of recurrent events at a moderately higher cost compared to monocomponents.

How consistent are cost-effectiveness estimates of a cardiovascular polypill strategy for the secondary prevention of cardiovascular disease across different cardiovascular risk equations?

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Ferre Internacional

Background

Risk equations (RE) are crucial to individualise estimates and properly adjust preventive treatments in patients with previous cardiovascular (CV) disease. RE are also routinely incorporated into health economic assessments but it is unknown if the cost-effectiveness results vary according to the RE applied.

Purpose

To determine the cost-effectiveness of a CV polypill (ASA 100mg, atorvastatin 20/40mg and ramipril 2.5/5/10mg) strategy compared to usual practice of combining monocomponents in the prevention of recurrent events in patients with previous coronary heart disease (CHD) or stroke applying two different CV RE: SMART and FRAMINGHAM, respectively.

Methods

A Markov cost-effectiveness model (1-year cycles; 4 health states: stable disease, subsequent CHD, subsequent stroke; death; payer perspective; direct medical costs; lifetime horizon; 4% discount rate) was developed for Portugal. Transition probability between health states was based on the SMART RE and an adaptation for secondary CV prevention of the FRAMINGHAM RE, respectively. Cost-effectiveness was calculated for a mixed cohort of secondary prevention patients (weighed post-CHD: 57.9%; post-stroke: 42.1%). Systematic literature reviews, Portuguese registries, mortality tables and official reports ware used to identify effectiveness, epidemiological, costs and utility data. Outcomes were costs (€, 2020) per life year (LY) and Quality Adjusted Life Year (QALY) gained. One-way (OWA) and probabilistic (PSA) sensitivity analyses tested the consistency of results. Assumptions were validated by experts.

Results

Applying the SMART RE, the incremental cost-effectiveness ratio (ICER) is 1,555€/LY gained and the incremental cost-utility ratio (ICUR) is 1,785€/QALY gained for the polypill strategy. The incremental costs of adopting the polypill strategy are 171,378€. Recurrent CV events (550.68 vs 642.13) and CV deaths (106.05 vs 122.81) are also less frequent with the polypill strategy compared with monocomponents. Assuming a willingness-to-pay (WTP) threshold of 30.000 €/QALY gained, there is a 77.80% probability for the polypill strategy to be cost-effective and 43.00% chances to be costs saving when used in a mixed cardiovascular and cerebrovascular disease population. Applying the FRAMINGHAM RE, the ICER is 998€/LY gained and the ICUR is 1,242€/QALY. The incremental costs amount 175,122€. Recurrent CV events (452.66 vs 563.48) and CV deaths (104.77 vs 127.32) are less frequent with the polypill strategy. The PSA shows a 99.5% probability for the polypill strategy to be cost-effective and 46.8% chances to be costs saving.

Conclusion

Both risk equations result in comparable results on the cost-effectiveness of interventions for the secondary prevention of CV disease. The polypill strategy remains cost-effective compared to the common practice of using individual monocomponents concomitantly, reducing recurrent CV events at a moderately higher cost.

[Septic shock. Update of treatment using hypertonic saline and antidiuretic hormone-vasopressin]

Safety in the use of small volumes of hypertonic saline solution for hypovolaemic shock and in the treatment of intracranial hypertension has been demonstrated in studies in the field of resuscitation. There is little experience of this for septic shock in humans. Beneficial immunomodulatory effects have been detected in pre-clinical studies. Interactions with the pituitary-adrenal axis and with the secretion of anti-diuretic hormone are varied and suggestive, but are not sufficiently understood. On the other hand, vasopressin has cardiovascular, osmoregulatory, and coagulation effects, and also acts on the hypothalamic-pituitary-adrenal axis. There is a relative deficit of vasopressin in septic shock. Its use in these patients does not seem to have any advantages as regards mortality, but may be beneficial in patients at risk from acute renal failure, or those who receive corticosteroids. Terlipressin is a vasopressin analogue that has also been studied. The synergy between vasopressin and hypertonic saline is a hypothesis that is mainly supported in pre-clinical studies. The use of hypertonic saline solution in septic shock, although promising, is still experimental, and must be restricted to the field of controlled clinical trials.

Optimization of (131)I doses for the treatment of hyperthyroidism

Several methods can be used to determine the activity of (131)I in the treatment of hyperthyroidism. However, many of them do not consider all the parameters necessary for optimum dose calculation. The relationship between the dose absorbed by the thyroid and the activity administered depends basically on three parameters: organ mass, iodine uptake and effective half-life of iodine in the thyroid. Such parameters should be individually determined for each patient in order to optimize the administered activity. The objective of this work is to develop a methodology for individualized treatment with (131)I in patients with hyperthyroidism of the Grave's Disease. A neck-thyroid phantom developed at the IRD was used to calibrate a scintillation camera and a uptake probe SCT-13004 at the Nuclear Medicine Center of the University Hospital of Rio de Janeiro and a uptake probe SCT-13002, available at the Nuclear Medicine Institute in Goiânia. The biokinetic parameters were determined based on measurements performed in eight voluntary patients. It is concluded that the use of the equipment available at the hospital (scintillation camera and uptake probe) has shown to be a suitable and feasible procedure for dose optimization in terms of effectiveness, simplicity and cost.

Treadmill exercise testing of asymptomatic men and women without evidence of heart disease

The aim of this study was to test the hypothesis of differences in performance including differences in ST-T wave changes between healthy men and women submitted to an exercise stress test. Two hundred (45.4%) men and 241 (54.6%) women (mean age: 38.7 +/- 11.0 years) were submitted to an exercise stress test. Physiologic and electrocardiographic variables were compared by the Student t-test and the chi-square test. To test the hypothesis of differences in ST-segment changes, data were ranked with functional models based on weighted least squares. To evaluate the influence of gender and age on the diagnosis of ST-segment abnormality, a logistic model was adjusted; P < 0.05 was considered to be significant. Rate-pressure product, duration of exercise and estimated functional capacity were higher in men (P < 0.05). Sixteen (6.7%) women and 9 (4.5%) men demonstrated ST-segment upslope >or=0.15 mV or downslope >or=0.10 mV; the difference was not statistically significant. Age increase of one year added 4% to the chance of upsloping of segment ST >or=0.15 mV or downsloping of segment ST >or=0.1 mV (P = 0.03; risk ratio = 1.040, 95% confidence interval (CI) = 1.002-1.080). Heart rate recovery was higher in women (P < 0.05). The chance of women showing an increase of systolic blood pressure <or=30 mmHg was 85% higher (P = 0.01; risk ratio = 1.85, 95%CI = 1.1-3.05). No significant difference in the frequency of ST-T wave changes was observed between men and women. Other differences may be related to different physical conditioning.

Dopamine D2 receptor polymorphisms in inflammatory bowel disease and the refractory response to treatment

Dopamine and its receptors may be involved in inflammatory reaction. The availability of this molecule depends on its receptors. The DRD2 gene, which codifies for the D2 dopamine receptor, has several polymorphisms. In this study, the DRD2 TaqIA polymorphism, which confers a decreased receptor density, was evaluated in 313 individuals including 220 inflammatory bowel disease patients (143 patients with Crohn's disease and 77 with ulcerative colitis) and in 93 healthy blood donors. The analysis was carried out by PCR-RFLP techniques. The frequencies of A (1) A (1) and A (2) A (2) genotypes were similar among Crohn's disease, ulcerative colitis patients, and health controls. Also, the genotype frequency was similar in different groups of disease localization, behavior, and age of disease onset. However, the Crohn's disease patients carriers of A (2) A (2) genotype showed a lower risk for development refractory Crohn's disease (37 out 65) than A (1) A (1) and A (1) A (2) carriers (28 out of 65) [(OR=0.4, 95% CI 0.21-0.87; p=0.02)]. Our results support an involvement of the dopamine receptor in inflammatory bowel disease and suggest a new potential target for therapy in refractory Crohn's disease patients.

Soluble selectins, sICAM, sVCAM, and angiogenic proteins in different activity groups of patients with inflammatory bowel disease

The endothelium is involved in the pathogenesis of inflammatory bowel disease (IBD). So far knowledge of the precise role of soluble adhesion molecules and angiogenic factors at different periods of activity in IBD is scarce or contradictory. Our goal in this study was to determine the serum levels of adhesion molecules and angiogenic factors in IBD patients at different periods of disease activity--clinical remission, biochemical evidence of inflammation, and clinical evidence of activity. We used a cross-sectional study design consisting of 218 patients (145 with Crohn's disease [CD] and 73 with ulcerative colitis [UC]) and 115 randomly assymptomatic blood donors. To assess disease activity, Harvey and Bradshaw's and Truelove-Witts' indexes were used. Circulating plasma sE-selectin (sE-S), sP-selectin (sP-S), human soluble vascular cell adhesion molecule-1 (sVCAM-1), and human soluble intercellular adhesion molecule-1 (sICAM-1) and serum levels of human vascular endothelial growth factor (VEGF), angiogenin (ANG), and placenta growth factor (P/GF) were measured with ELISAs. The amount of mRNA VEGF in blood mononuclear cells was also evaluated. In inactive CD patients, serum levels of sP-S, sE-S, sVCAM, and sICAM were significantly lower (P < 0.05) than in controls. In active CD patients, only the sE-S values were higher than in controls. In UC patients, sP-S and sVCAM levels were significantly lower than those in controls. Considering growth factors, CD patients in remission had levels of ANG and VEGF lower than those found in controls. The VEGF RNAm in blood mononuclear cells was similar among all CD activity groups. In conclusion, in UC patients the serum levels of VEGF, ANG, and P/GF were similar to those in controls. The serum levels of adhesion molecules and angiogenic factors were low in IBD patients in periods of remission. Low levels of angiogenic factors in inactive CD patients suggest dysfunction of the angiogenic process and wound repair.

Gemifloxacin inhibits cytokine secretion by lipopolysaccharide stimulated human monocytes at the post-transcriptional level

The fluroquinolone gemifloxacin was examined for its capacity to modulate secretion of cytokines by human monocytes stimulated with lipopolysaccharide (LPS). Monocytes from six male and two female healthy volunteers were stimulated with LPS, exposed to gemifloxacin and the amounts of secreted IL-1 alpha, IL-1 beta, IL-6, IL-10 and TNF-alpha measured at 3, 6 and 24 h. The results revealed that LPS alone increased secretion of each cytokine significantly. Treatment of the LPS-stimulated monocytes with gemifloxacin resulted in a significant inhibition (p < 0.01) of secretion of each of the cytokines from monocytes of the eight volunteers. Nuclear extracts of the human monocyte cell line, THP-1, were used in the electrophoretic mobility shift assay to determine whether gemifloxacin affects nuclear factor-kappa B (NF-kappa B) activation. In addition, RNA from THP-1 cells was used in Northern blots to determine whether inhibition of secretion of IL-1 beta and TNF-alpha by gemifloxacin occurred at the transcription or translation level. Whereas LPS induced a rapid increase in NF-kappa B activation, gemifloxacin alone did not. Gemifloxacin did not affect the kinetics or decrease the extent of activation. Northern blots indicated that the inhibitory activity of gemifloxacin occurred post-transcription. Thus, gemifloxacin may modulate the immune response by altering secretion of cytokines by human monocytes. Although the concentrations of gemifloxacin used were higher than those observed in the serum of human volunteers treated with the dose under clinical development, it should be taken into consideration that concentrations at tissue and intracellular levels may be considerably higher than serum concentrations.

[Giant evoked potentials]

INTRODUCTION

There are many, diverse nosological entities with the common factor of the genesis of cortical evoked potentials of great amplitude, commonly known as giant evoked potentials. In most cases they are conditions with the common clinical condition of myoclonic of cortical origin, such as progressive myoclonic epilepsy, generalized idiopathic epilepsy, myoclonias of toxic, infectious or postanoxic origin. Giant potentials have been shown both in studies of focal hemisphere lesions and in some cases of patients with corticobasal degeneration.

OBJECTIVE

The aim of this paper was to show, by presenting interesting cases, some of the conditions mentioned and to review some concepts concerning the mechanisms which may be involved in the production of these electrophysiological responses.

PATIENTS AND METHODS

We studied 6 patients aged between 2 and 22 years, in whom multimodal evoked potentials, electroencephalograms and imaging studies had been done.

RESULTS

Giant somatosensory potentials were shown in the patients with obvious myoclonia. Visual potentials of great amplitude were common to the other patients presented, with or without myoclonia.

CONCLUSION

Giant evoked potentials respond to a state of cortical hyperexcitability which may have various causes.

Prevalence between different alpha subunits performing the benzodiazepine binding sites in native heterologous GABA(A) receptors containing the alpha2 subunit

The presence of two heterologous alpha subunits and a single benzodiazepine binding site in the GABA(A) receptor implicates the existence of pharmacologically active and inactive alpha subunits. This fact raises the question of whether a particular alpha subtype could predominate performing the benzodiazepine binding site. The hippocampal formation expresses high levels of alpha subunits with different benzodiazepine binding properties (alpha1, alpha2 and alpha5). Thus, we first demonstrated the existence of alpha2-alpha1 (36.3 +/- 5.2% of the alpha2 population) and alpha2-alpha5 (20.2 +/- 2.1%) heterologous receptors. A similar alpha2-alpha1 association was observed in cortex. This association allows the direct comparison of the pharmacological properties of heterologous native GABA(A) receptors containing a common (alpha2) and a different (alpha1 or alpha5) alpha subunit. The alpha2 subunit pharmacologically prevailed over the alpha1 subunit in both cortex and hippocampus (there was an absence of high-affinity binding sites for Cl218,872, zolpidem and [3H]zolpidem). This prevalence was directly probed by zolpidem displacement experiments in alpha2-alpha1 double immunopurified receptors (K(i) = 295 +/- 56 nM and 200 +/- 8 nM in hippocampus and cortex, respectively). On the contrary, the alpha5 subunit pharmacologically prevailed over the alpha2 subunit (low- and high-affinity binding sites for zolpidem and [3H]L-655,708, respectively). This prevalence was probed in alpha2-alpha5 double immunopurified receptors. Zolpidem displayed a single low-affinity binding site (K(i) = 1.73 +/- 0.54 microM). These results demonstrated the existence of a differential dominance between the different alpha subunits performing the benzodiazepine binding sites in the native GABA(A) receptors.

Distribution of the gamma-aminobutyric acid(A) receptor complex alpha 5 subunit in chick brain. An immunocytochemical and autoradiographic study

This work reports the distribution of the gamma-aminobutyric acid(A) (GABA(A)) receptor complex alpha5 subunit in the chick using an antibody raised against this subunit in the rat, an immunoprecipitation study and a comparative autoradiographic study using [(3)H]flunitrazepam in the presence of 1 microM zolpidem, which is considered to bind only to those areas presenting the alpha5 subunit. The specificity of the antibody for the chick GABA(A) receptor complex alpha5 subunit is supported by the similar bands obtained by Western blotting from rat and chick, the immunoprecipitation study and the general agreement in the distribution and pattern of labelling of this antibody in both species. The immunocytochemical and autoradiographic distributions in both the chick and rat are compared and some areas with disagreement between these distributions are discussed. The general conclusion is that the alpha5 subunit of the GABA(A) complex receptor seems to have been conserved along evolution.

GABAA and alpha-amino-3-hydroxy-5-methylsoxazole-4-propionate receptors are differentially affected by aging in the rat hippocampus

We have investigated the age-dependent modifications in the expression of eight different subunits of the gamma-aminobutyric acid, type A (GABA(A)) receptor (alpha1, alpha2, alpha3, alpha5, beta2, beta3, gamma2S, and gamma2L) and all four subunits of the alpha-amino-3-hydroxy-5-methylsoxazole-4-propionate (AMPA) receptor (GluR1-4) in the hippocampus of 24-month-old rats. All aged hippocampi displayed a remarkable increase (aged/adult ratio, 3.53 +/- 0.54) in the mRNA levels of the short version of the gamma2 subunit in parallel with a similar increase in the gamma2 subunit protein (aged/adult ratio, 2.90 +/- 0.62). However, this increase was not observed in the mature receptor. On the other hand, the expression of the different alpha subunit mRNAs increased moderately with aging, displaying a heterogeneous pattern. The most frequent modification consisted in an increase in the expression of the alpha1 subunit mRNA (aged/adult ratio, 1.26 +/- 0.18), in parallel with a similar increase on the alpha1 protein (aged/adult ratio, 1. 27 +/- 0.12) and in the alpha1 incorporated to the assembled GABA(A) receptor (tested by immunoprecipitation; aged/adult ratio, = 1.20 +/- 0.10). However, in the same hippocampal samples, no major modifications were observed on the expression of the AMPA receptor subunits. As a whole, these results indicated the existence of an increased expression of the GABA(A) receptor subunits and a preservation of the AMPA receptor at the hippocampal formation. These modifications could reflect the existence of specific deficiencies (neuronal loss and/or deafferentiation) on the GABAergic system in the aged rats.

Native gamma-aminobutyric acid type A receptors from rat hippocampus, containing both alpha 1 and alpha 5 subunits, exhibit a single benzodiazepine binding site with alpha 5 pharmacological properties

Evidences indicate the existence of two homologous and/or heterologous alpha subunits coassembled in a single gamma-aminobutyric acid type A (GABA(A)) receptor. However, it is unknown whether both or only one of the coassembled alpha subunits display benzodiazepine binding sites. Thus, we have investigated the association between alpha1 and alpha5 subunits and the pharmacological properties of these GABA(A) receptors from rat hippocampus. The association between alpha1 and alpha5 subunits was demonstrated by immunoblot of the anti-alpha1 or -alpha5 immunoaffinity-purified receptors and by double immunopurification by anti-alpha1 and -alpha5 columns in series. The benzodiazepine binding properties of the immunoprecipitated receptors indicated the existence of pharmacologically active and inactive alpha subunits. The anti-alpha5 immunoprecipitated receptors displayed exclusively low-affinity binding sites for both Cl218,872 (K(i) = 0.81 +/- 0.15 microM) and zolpidem (K(i) = 5.0 +/- 3.0 microM), in spite of the association between alpha1 and alpha5 subunits. The anti-alpha1 immunoprecipitated receptors displayed both high- and low-affinity binding sites for both ligands (K(i)s = 47.5 +/- 5.2 nM and 0.7 +/- 0.06 microM for Cl218,872 and 25.0 +/- 7.0 nM, 415 +/- 200 nM and 9. 3 +/- 3.0 microM for zolpidem). Therefore, the alpha5 subunit, when coassembled with alpha1 subunit, should be pharmacologically predominant. This hypothesis was probed by immunoprecipitation of the photoaffinity-labeled receptors and by anti-alpha1 and -alpha5 double immunopurified receptors. The alpha1-alpha5 double immunopurified receptors displayed a single low-affinity binding site (K(i) = 908 +/- 105 nM) for Cl218,872, undetectable [(3)H]zolpidem binding activity, and similar [(3)H]flumazenil and [(3)H]L-655,708 binding activity (0.10 +/- 0.01 and 0.09 +/- 0.02 pmol/20 microliters of anti-alpha5 immunobeads, respectively). Thus, the native GABA(A) receptors containing alpha1 and alpha5 subunits have only one alpha subunit pharmacologically active displaying alpha5 binding properties.

Pharmacological properties of the GABA(A) receptor complex from brain regions of (hypoemotional) Roman high- and (hyperemotional) low-avoidance rats

The pharmacological properties of benzodiazepine binding sites of the gamma-aminobutyric acid (GABA)A receptor complex from cortical, hippocampal and cerebellar membranes of Roman high-avoidance (RHA/Verh) and Roman low-avoidance (RLH/Verh) rats were investigated. No major differences between the two lines were found in the binding parameters of [3H]flunitrazepam (a non-selective agonist). [3 H]zolpidem (a Type I selective agonist) or [3 H]ethyl 8-azido-6-dihydro-5-methyl-6-oxo-4H-imidazol[1,5-a]-[1,4]benzodiazepine- 3-carboxylate (Ro15-4513) (a partial inverse agonist). Neither the Kd values nor the Bmax for these ligands differed between RHA/Verh and RLA/Verh rats in any of the brain regions studied. As a result, the proportion of Type I binding sites in cortical and hippocampal membranes of RHA/Verh and RLA/Verh rats or the 'diazepam-sensitive' and the 'diazepam-insensitive' binding sites in cerebellar membranes, calculated from the [3H]flunitrazepam and [3H]zolpidem maximal binding sites or from [3H]Ro15-4513 binding (in the absence or in presence of diazepam), respectively, was also similar. Furthermore, there were no differences between the two rat lines in the allosteric interactions between GABA and the benzodiazepine binding sites (labeled with [3H]flunitrazepam) in all three areas tested or the Type I binding sites (labeled with [3H]zolpidem) in the hippocampus. In contrast, RLA/Verh rats showed a significant reduction in the allosteric interactions between GABA and [3H]zolpidem binding sites in the cortex. As a whole, these results indicate the absence of generalized between-line differences in the GABA(A) receptor complex showing, at the same time, the existence of some specific differences in allosterism within the GABA(A) complex. These differences may contribute to the divergent emotional responses which characterize the RHA/Verh and RLA/Verh rat lines.

Absence of association between delta and gamma2 subunits in native GABA(A) receptors from rat brain

We investigated the possible association between delta and gamma2 subunits in native GABA(A) receptors, from different rat brain regions, using subunit-specific anti-delta and anti-gamma2 antibodies. Previous reports have provided somewhat controversial results, indicating both the presence and the absence of association between these two subunits in native receptors. Our results indicate the absence of co-localization between delta and gamma2 subunits. In immunoprecipitation experiments, anti-delta antibody consistently immunoprecipitated [3H]muscimol binding activity (GABA binding sites) from all brain areas tested (10-20% of the total binding). However, under the same conditions, no significant [3H]flumazenil or [3H]ethyl 8-azido-6-dihydro-5-methyl-6-oxo-4H-imidazol[1,5-a]-[1,4]benzodiazepine- 3-carboxylate (Ro15-4513) binding (benzodiazepine binding sites) activity was detected in the immunopellets. These results indicate the absence of association between delta and gamma2 subunits. This question was directly addressed by immunopurification and Western blot experiments. As expected, no gamma2 subunits were detected in anti-delta immunoaffinity purified receptors. Conversely, no delta subunits were identified in anti-gamma2 immunopurified receptors. Thus, these results demonstrate the absence of association between delta and gamma2 subunits in native GABA(A) receptors. Finally, our results also indicate the relevance of the solubilization conditions on the apparent association between different subunits of the native GABA(A) receptor complex.

Chronic infection with Toxoplasma gondii does not prevent acute disease or colonization of the brain with tissue cysts following reinfection with different strains of the parasite

Two strains of Toxoplasma gondii with different capacities to induce disease and brain lesions in mice were used to study the effects of reinfection with the parasite on a previously infected host. In spite of marked antibody and cell-mediated immune responses, chronically infected mice developed disease and died of acute toxoplasmosis when reinfected with a strain different from the one causing the primary infection. Moreover, the marked antibody and cell-mediated immune responses of the chronically infected mice did not prevent invasion of their brains and formation of tissue cysts by the reinfecting strain. Tissue cysts of the reinfecting strain were demonstrated in the brains of the chronically infected and subsequently reinfected mice. These results highlight the importance of strain differences in the pathogenesis of toxoplasmosis.

GABAA receptor subunit expression changes in the rat cerebellum and cerebral cortex during aging

Significant aging-related decreased expression of various GABAAR subunit mRNAs (alpha 1, gamma 2, beta 2, beta 3 and sigma) was found in both cerebellum and cerebral cortex using quantitative dot blot and in situ hybridization techniques. Contrary to the other subunits, the alpha 6 mRNA expression was significantly increased in the aged cerebellum. Parallel age-related changes in protein expression for gamma 2 and beta 2/3 (decrease) and alpha 6 (increase) were revealed in cerebellum by quantitative immunocytochemistry. However, no significant changes in alpha 1 protein expression nor in the number or affinity of [3H]zolpidem binding sites were detected in cerebellum even though alpha 1 mRNA expression was significantly decreased in the aged rat. Age-related increased expression of alpha 6 mRNA and protein in the cerebellum was accompanied by no significant changes in the number of diazepam-insensitive [3H]Ro15-4513 binding sites. In the cerebral cortex, no changes in the protein expression of the main GABAA receptor subunits (alpha 1, gamma 2 and beta 2/3) were observed which contrasted with the age-related decreased expression of the corresponding mRNAs. No significant changes in the number or affinity of [3H]zolpidem binding sites were observed in the cerebral cortex. Thus, age-related changes in the mRNA expression of a particular subunit does not necessarily lead to similar changes in protein or assembly into mature GABAA receptors. The results reveal the existence of complex regulatory mechanisms of GABAA receptor expression, at the transcriptional, translational and post-translational and/or assembly levels, which vary with the subunit and brain area.

Molecular and pharmacological characterization of native cortical gamma-aminobutyric acidA receptors containing both alpha1 and alpha3 subunits

We have investigated the existence, molecular composition, and benzodiazepine binding properties of native cortical alpha1-alpha3 gamma-aminobutyric acidA (GABAA) receptors using subunit-specific antibodies. The co-existence of alpha1 and alpha3 subunits in native GABAA receptors was demonstrated by immunoblot analysis of the anti-alpha1- or anti-alpha3-immunopurified receptors and by immunoprecipitation experiments of the [3H]zolpidem binding activity. Furthermore, immunodepletion experiments indicated that the alpha1-alpha3 GABAA receptors represented 54.7 +/- 5.0 and 23.6 +/- 3.3% of the alpha3 and alpha1 populations, respectively. Therefore, alpha1 and alpha3 subunits are associated in the same native GABAA receptor complex, but, on the other hand, these alpha1-alpha3 GABAA receptors from the cortex constitute a large proportion of the total alpha3 population and a relatively minor component of the alpha1 population. The pharmacological analysis of the alpha1- or alpha3-immunopurified receptors demonstrated the presence of two different benzodiazepine binding sites in each receptor population with high (type I binding sites) and low (type II binding sites) affinities for zolpidem and Cl 218,872. These results indicate the existence of native GABAA receptors possessing both alpha1 and alpha3 subunits, with alpha1 and alpha3 subunits expressing their characteristic benzodiazepine pharmacology. The molecular characterization of the anti-alpha1-anti-alpha3 double-immunopurified receptors demonstrated the presence of stoichiometric amounts of alpha1 and alpha3 subunits, associated with beta2/3, and gamma2 subunits. The pharmacological analysis of alpha1-alpha3 GABAA receptors demonstrated that, despite the fact that each alpha subunit retained its benzodiazepine binding properties, the relative proportion between type I and II binding sites or between 51- and 59-61-kDa [3H]Ro15-4513-photolabeled peptides was 70:30. Therefore, the alpha1 subunit is pharmacologically predominant over the alpha3 subunit. These results indicate the existence of active and nonactive alpha subunits in the native alpha1-alpha3 GABAA receptors from rat cortex.

Age-related modifications on the GABAA receptor binding properties from Wistar rat prefrontal cortex

In the present communication we have investigated the pharmacological properties of the GABAA receptor from adult (3 months old) and aged (24 months old) Wistar rat prefrontal cortex. The prefrontal cortex is implicated in cognitive functions and stress and both processes seem to be altered during aging. These changes could be mediated by modifications in the GABAA receptor properties. Our results indicated the absence of generalized age-related modifications on the pharmacological properties of the GABAA receptor from prefrontal cortical membranes. Saturation experiments using the non-selective benzodiazepine [3H]flunitrazepam revealed that neither the Kd values or the Bmax were modified during aging. Moreover, Cl 218 872 displacement of [3H]flunitrazepam showed no age-related modifications on either the Kis or the relative proportion between the Type I and Type II benzodiazepine binding sites. Therefore, the benzodiazepine binding sites are well preserved in aged prefrontal cortex. On the other hand, saturation experiments using the GABA agonist [3H]muscimol demonstrated in the Bmax of the low affinity [3H]muscimol binding sites in aged rats (4.3 +/- 0.8 pmol/mg protein vs. 2.3 +/- 0.2 pmol/mg protein in adult and aged rats, respectively). However, no age-dependent modifications were observed in the allosteric interaction between GABA and benzodiazepine binding sites. These results demonstrate that the benzodiazepine binding sites and the GABA binding sites of the GABAA receptor complex from rat prefrontal cortical membranes are differentially affected by the aging process.

Interleukin-12-mediated resistance to Trypanosoma cruzi is dependent on tumor necrosis factor alpha and gamma interferon

The aim of this study was to determine if interleukin-12 (IL-12) has a role in the immune response to Trypanosoma cruzi. Infection of BALB/c mice with the virulent Tulahuen strain of T. cruzi is characterized by a high-level parasitemia, pathology in the heart associated with the presence of amastigotes, and death during the acute phase of the disease. Administration of IL-12 to BALB/c mice infected with T. cruzi resulted in a reduced parasitemia and a significant delay in the time to death compared with those for infected controls. This protective effect was correlated with increased levels of gamma interferon (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) in serum. To determine if these cytokines were involved in the protective effects of IL-12, we treated infected mice with IL-12 alone or in combination with monoclonal antibodies specific for IFN-gamma or TNF-alpha. These antibodies antagonized the protective effect of exogenous IL-12. Treatment of infected mice with a polygonal antibody specific for IL-12 resulted in a significant increase in parasitemia but did not affect the time to death. These latter studies demonstrate a role for endogenous IL-12 in resistance to T. cruzi. Together, our data identify an IL-12-mediated mechanism of resistance to T. cruzi, which is dependent on IFN-gamma and TNF-alpha.

Uniject as a delivery system for the once-a-month injectable contraceptive Cyclofem in Brazil

This study assessed the administration of Cyclofem using prefilled Uniject devices. A total of 480 injections were administered divided equally between standard syringes and Uniject. The majority of women (82%) reported that they felt anxious prior to receiving the injection with Uniject. After injection, more than 80% expressed no anxiety about the appearance of Uniject or about the technique of injection. A total of 96.3% of the participants reported slight to no pain with Uniject. In comparison to the standard syringe, 5.6% expressed having had more pain with Uniject. Ninety percent of the service providers reported that Uniject was easy to activate and inject and that it was reassuring for users to know that the syringe and needle had never been used previously. Only two service providers demonstrated difficulties in activating the device. No accidental punctures occurred during the manipulation, and incomplete emptying of the Uniject was not observed. In conclusion, Uniject is a good device for the administration of the injectable contraceptive Cyclofem. It is likely to be appropriate for the delivery of other injectable contraceptives after the necessary stability tests have been performed.

Some phosphonic acid analogs as inhibitors of pyrophosphate-dependent phosphofructokinase, a novel target in Toxoplasma gondii

Pyrophosphate-dependent phosphofructokinase (PPi-PFK) was identified previously in Toxoplasma gondii as the only kinase that phosphorylates fructose-6-P to fructose-1,6-bisP. Since such an enzyme is not present in mammals, it was considered to be a good target for prospective selective inhibitors of the parasite. We have examined the effects of several phosphonic acid derivatives, analogs of pyrophosphate, on PPi-PFK activity, as well as on the replication of T. gondii in human foreskin fibroblast (HFF) cells. The most active compound in inhibiting PPi-PFK was tetrasodium carbonyldiphosphonate. Several bisphosphonates and related arylhydrazones showed inhibition of the enzyme, but with higher IC50 values. Although several phosphonoacetic acid derivatives also inhibited PPi-PFK, as a group they were less potent than the bisphosphonate derivatives. Comparison among the structures of various inhibitors and their effects against PPi-PFK indicates that a carbonyl (C=O) or amino (C=N) group between two phosphoryl moieties is associated with more potent enzyme inhibiton. Tetrasodium carbonyldiphosphonate did not show a significant effect against replication of T. gondii cells, probably because, as a charged molecule, it could not cross the cell membrane to reach the intracellular parasite. Tetraisopropyl carbonyldiphosphonate 2,4-dinitrophenylhydrazone showed some selective inhibitory effect against replication of the parasite in the HFF cells and protected the mammalian cells from damage by T. gondii. The results indicate that carbonyldiphosphonic acid is a good prototype compound that is amenable to chemical manipulation, which, in turn, may optimize selective inhibition of T. gondii PPi-PFK and increase accessibility to the intracellular parasite.

Molecular characterization of type I GABAA receptor complex from rat cerebral cortex and hippocampus

The molecular composition of the native gamma-aminobutyric acidA (GABAA) receptor complex is actually unknown. In the present communication we report a novel approach to characterize the minimal molecular conformation of the native GABAA receptor complex. This novel approach is based on the combination of subunit specific antibodies and specific 3H-labeled ligands in immunoprecipitation experiments. We have determined the presence of beta 2/3 and gamma 2 subunits in the Type I GABAA receptor complex, from rat cerebral cortex and hippocampus, by using two antibodies, the monoclonal 62-3G1 (specific for beta 2/3) and the polyclonal anti-gamma 2 (to the large intracellular loop of the gamma 2 short form) together with the Type I-specific ligand [3H]zolpidem. The association of gamma 2 and beta 2/3 subunits with the GABAA receptor complex was also tested using [3H]flumazenil. The results indicated that both gamma 2 and beta 2/3 were the most abundant subunits associated to either Type I or total benzodiazepine receptors from both cortex and hippocampus. Between 70-80% of Type I or total benzodiazepine binding activity was immunoprecipitated by either antibody. In addition, we have also investigated the coexistence of both subunits as part of the same population of Type I GABAA receptor complex by cross-immunoprecipitation experiments with 62-3G1 and anti-gamma 2. The results indicated that, in cerebral cortex, both gamma 2 and beta 2/3 subunits were part of the same population of Type I receptors. In hippocampus, an additional 20% of Type I receptors displayed either gamma 2 or beta 2/3 but not both subunits.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of beta interferon in resistance to Toxoplasma gondii infection

The role of recombinant murine beta interferon (rMuIFN-beta) and recombinant human IFN-beta (rHuIFN-beta) in resistance to Toxoplasma gondii was examined. rMuIFN-beta protected mice against a lethal infection with the parasite. The protective effect appeared to depend on the concomitant release of gamma interferon. rMuIFN-beta did not activate murine peritoneal macrophages to inhibit or kill T. gondii whether used alone or in combination with lipopolysaccharide (LPS). rHuIFN-beta did not activate human monocyte-derived macrophages to inhibit or kill T. gondii when 5-day-old monocyte-derived macrophages were used. In contrast, significant killing of T. gondii was noted when 10-day-old monocyte-derived macrophages were used. The addition of LPS enhanced this effect. These results revealed a role for IFN-beta in the mechanisms of defense against T. gondii and suggest its potential use in the treatment of toxoplasmosis in humans.