Armoring CRAds with p21/Waf-1 shRNAs: the next generation of oncolytic adenoviruses

Conditionally replicating adenoviruses (CRAds) represent a promising modality for the treatment of neoplastic diseases, including Prostate Cancer. Selectively replicating viruses can be generated by placing a tissue or cancer-specific promoter upstream of one or more of the viral genes required for replication (for example, E1A, E1B). We have previously reported multiple cellular processes that can attenuate viral replication, which in turn compromises viral oncolysis and tumor kill. In this study, we investigated the importance of the cyclin-dependent kinase inhibitor p21/Waf-1, on viral replication and tumor growth. To our knowledge, this is the first report describing the importance of p21/Waf-1shRNA on the induction of an androgen responsive element (ARE) based promoter driving the E1A gene. As a proof of concept, the study emphasizes the use of RNA interference technology to overcome promoter weaknesses for tissue-specific oncolytic viruses, as well as the cellular inhibitor pathways on viral life cycle. Using RNA interference against p21/Waf-1, we were able to show an increase in viral replication and viral oncolysis of prostate cancer cells. Similarly, CRAd viruses that carry p21/Waf-1 shRNA (Ad5-RV004.21) were able to prevent tumor outgrowth that resulted in a marked increase in the mean survival time of tumor-bearing mice compared with CRAd without p21/Waf-1 shRNA (Ad5-RV004). In studies combining Ad5-RV004.21 with Adriamycin, a suprar-additive effect was observed only in CRAds that harbor shRNA against p21/Waf-1. Taken together, these findings of enhanced viral replication in prostate cancer cells by using RNA interference against the cdk inhibitor p21/Waf-1 have significant implications in the development of prostate-specific CRAd therapies.

Systemic inhibition of the Na(+)/H (+) exchanger type 3 in intact rats activates brainstem respiratory regions

Selective inhibition of the Na(+)/H(+) exchanger type 3 (NHE3) increases the firing rate of brainstem ventrolateral CO(2)/H(+) sensitive neurons, resembling the responses evoked by hypercapnic stimuli. In anesthetized animals, NHE3 inhibition has also been shown to stimulate the central chemosensitive drive. We aimed to analyze the respiratory-related brainstem regions affected by NHE3 inhibition in anaesthetized spontaneously-breathing rats with intact peripheral afferents. For that, c-Fos immunopositive cells were counted along the brainstem in rats intravenously infused with the selective NHE3 inhibitor AVE1599. A rostral extension of the ventral respiratory column which includes the pre-Bötzinger complex was activated by the NHE3 inhibitor. In addition, the number of c-Fos positive cells resulted significantly increased in the most rostral extension of the retrotrapezoid nucleus/parapyramidal region. In the pons, the intravenous infusion of AVE1599 activated the lateral parabrachial and Kölliker-Fuse nuclei. Thus, selective NHE3 inhibition in anaesthetized rats activates the respiratory network and evokes a pattern of c-Fos expressing cells similar to that induced by hypercapnia.

Relationship between adherence level, type of the antiretroviral regimen, and plasma HIV type 1 RNA viral load: a prospective cohort study

The relationship between adherence, antiretroviral regimen, and viral load (VL) suppression was assessed through a 1 year prospective follow-up study among 1142 HIV-infected patient. Patients on antiretroviral therapy who attended to the pharmacy during a 6-month period were considered eligible. Those included in the final analysis were patients who had been taking the same antiretroviral therapy for > or =6 months since their inclusion. The cohort included patients taking first line therapy (n = 243) and antiretroviral-experienced patients (n = 899). Naive patients who were included had to have reached undetectable VL at enrollment. Antiretroviral-experienced patients with detectable VL determinations in the previous 6 months were excluded. Adherence was measured by means of announced pill counts and dispensation pharmacy records. Of patients, 58% were taking NNRTI, 31.4% boosted PI, and 10.6% unboosted PI-based regimens. Overall, the relative risk of virologic failure was 9.0 (95% CI 4.0-20.1) in patients with adherence 80-89.9%, 45.6 (95% CI 19.9-104.5) with adherence 70-79.9%, and 77.3 (95% CI 34.2-174.9) with adherence <70%, compared with adherence of > or =90%. The risk of virologic failure in patients with adherence <90% taking unboosted PI was 2.5 times higher than the group taking boosted PI (95% CI 1.2-5.3). There were no statistical differences in patients taking boosted PI and those who were taking NNRTI. Less than 95% of adherence is associated with high virologic success. For patients taking NNRTI- or boosted PI-based regimens with adherence rates of 80%, the failure rate is <10%. These data do not affect the goal of achieving the highest level of adherence possible.

Syntheses, Crystal Structures, and Magnetic Properties of Metal−Organic Hybrid Materials of Cu(II): Effect of a Long Chain Dicarboxylate Backbone, and Counteranion in Their Structural Diversity

Eight new metal-organic hybrid materials of Cu(II) have been synthesized by using flexible glutarate/adipate as a bridging ligand, 2,2'-bipyridine/1,10-phenanthroline as a chelating ligand, and BF4-/ClO4-/Cl- as a counteranion. These materials are characterized by single-crystal X-ray diffraction analyses and variable temperature magnetic measurements. Out of them, complexes 1, 3, 5, and 8 crystallize in the triclinic system with space group P. Complexes 2, 4, 6, and 7 crystallize in the monoclinic system with space group P21/n (2, 4), P21/c (6), and C2 (7). The structural analysis reveals that bridging glutarate gives rise to dinuclear and tetranuclear species, whereas the adipate dianion leads to octanuclear, one-dimensional and two-dimensional polymeric complexes, although they have been prepared under similar conditions. Supramolecular architectures of higher dimensionality have been achieved through H-bonding and pi-pi interaction. In all the complexes, the bridging and/or counteranions as well as chelating ligand have a vital role in directing the solid-state structure. A variable temperature (2-300 K) magnetic susceptibility study discloses the antiferromagnetic coupling for all of the complexes.

7-Bromoindirubin-3'-oxime induces caspase-independent cell death

Indirubin, an isomer of indigo, is a reported inhibitor of cyclin-dependent kinases (CDKs) and glycogen synthase kinase-3 (GSK-3) as well as an agonist of the aryl hydrocarbon receptor (AhR). Indirubin is the active ingredient of a traditional Chinese medicinal recipe used against chronic myelocytic leukemia. Numerous indirubin analogs have been synthesized to optimize this promising kinase inhibitor scaffold. We report here on the cellular effects of 7-bromoindirubin-3'-oxime (7BIO). In contrast to its 5-bromo- and 6-bromo- isomers, and to indirubin-3'-oxime, 7BIO has only a marginal inhibitory activity towards CDKs and GSK-3. Unexpectedly, 7BIO triggers a rapid cell death process distinct from apoptosis. 7-Bromoindirubin-3'-oxime induces the appearance of large pycnotic nuclei, without classical features of apoptosis such as chromatin condensation and nuclear fragmentation. 7-Bromoindirubin-3'-oxime-induced cell death is not accompanied by cytochrome c release neither by any measurable effector caspase activation. Furthermore, the death process is not altered either by the presence of Q-VD-OPh, a broad-spectrum caspase inhibitor, or the overexpression of Bcl-2 and Bcl-XL proteins. Neither AhR nor p53 is required during 7BIO-induced cell death. Thus, in contrast to previously described indirubins, 7BIO triggers the activation of non-apoptotic cell death, possibly through necroptosis or autophagy. Although their molecular targets remain to be identified, 7-substituted indirubins may constitute a new class of potential antitumor compounds that would retain their activity in cells refractory to apoptosis.

[Acid and non-acid gastro-esophageal reflux in newborns. Preliminar results using intraluminal impedance]

Preterm infants present often Gastroesophageal refluxes (GER). Esophageal pH monitoring to reflux detection is of limited use in this infants because their gastric pH is normally higher than 4 for 90% of the time. Other methods such as the Intraluminal Impedance Technique (MII) technique and the use of micromanometric catheters try to palliate the difficulties for measuring GER by pH monitoring. The aim of this study, in a first step, was to obtain the normal Intraluminal Impedance values on control children and, in a second step, to study the relationship between GER and cardiorespiratory episodes using simultaneous recording of the end-tidal fraction of expired CO2, 02 saturation by pulse-oximetry, respiratory frequency, esophageal impedance and manometry, gastro-esophageal pHmetry, and electrocardiography in selected patients. Data from simultaneous pH and Intraluminal Impedance during 24 hours in 7 control preterms showed 89 acid refluxes, 192 non-acid refluxes, 79.36% of all refluxes reached the proximal esophagus. Therefore the impedance is an innocuous method which opens new horizons in the study of such a common illness as the GER in the preterm infants.

Rare Azido-Bridged Manganese(II) Systems: Syntheses, Crystal Structures, and Magnetic Properties

Two new polymeric azido-bridged manganese complexes of formulas [Mn(N3)2 (bpee)]n (1) and {[Mn(N3)(dpyo)Cl(H2O)2](H2O)}n (2) [bpee, trans-1,2-bis(4-pyridyl)ethylene; dpyo, 4,4'-dipyridyl N,N'-dioxide] have been synthesized and characterized by single-crystal X-ray diffraction analysis and low-temperature magnetic study. Both the complexes 1 and 2 crystallize in the triclinic system, space group P1, with a = 8.877(3) A, b = 11.036(3) A, c = 11.584(4) A, alpha = 72.62(2) degrees, beta = 71.06(2) degrees, gamma = 87.98(3) degrees, and Z = 1 and a = 7.060(3) A, b = 10.345(3) A, c = 11.697(4) A, alpha = 106.86(2) degrees, beta = 113.33(2) degrees, gamma = 96.39(3) degrees, and Z = 2, respectively. Complex 1 exhibits a 2D structure of [-Mn(N3)2-]n chains, connected by bpee ligands, whose pyridine rings undergo pi-pi and C-H...pi interactions. This facilitates the rare arrangement of doubly bridged azide ligands with one end-on and two end-to-end (EO-EE-EE) sequence. Complex 2 is a neutral 1D polymer built up by [Mn(N3)(dpyo)Cl(H2O)2] units and lattice water molecules. The metals are connected by single EE azide ligands, which are arranged in a cis position to the Mn(II) center. The 1D zipped chains are linked by H-bonds involving lattice water molecules and show pi-pi stacking of dpyo pyridine rings to form a supramolecular 2D layered structure. The magnetic studies were performed in 2-300 K temperature range, and the data were fitted by considering an alternating chain of exchange interactions with S = 5/2 (considered as classical spin) with the spin Hamiltonians H = -Ji sigma(S(3i)S(3i+1) + S(3i+1)S(3i+2)) - J2 sigmaS(3i-1)S(3i) and H = -Ji sigmaS(2i)S(2i+1) - J2 sigmaS(2i+1)S(2i+2) for complexes 1 and 2, respectively. Complex 2 exhibits small antiferromagnetic coupling between the metal centers, whereas 1 exhibits a new case of topological ferromagnetism, which is very unusual.

Highly H+-sensitive neurons in the caudal ventrolateral medulla of the rat

The ventral surface of the caudal ventrolateral medulla (cVLM) has been shown to generate intense respiratory responses after surface acid-base stimulation. With respect to their chemosensitive characteristics, cVLM neurons have been less studied than other rostral-most regions of the brainstem. The purpose of these experiments was to determine the bioelectric responses of cVLM neurons to acidic stimuli and to determine their chemosensitive properties. Using extracellular and microiontophoretic techniques, we recorded electrical activities from 117 neurons in an area close to the ventral surface of the cVLM in anaesthetised rats. All neurons were tested for their sensitivity to H+. The fluorescent probe BCECF was used to measure extracellular pH changes produced by the microiontophoretic injection of H+ in brainstem slices. This procedure provided an estimation of the local changes in pH produced by microiontophoretic H+ application in the anaesthetised rat. Neurons coupled to the respiratory cycle, R (n = 51), were not responsive to direct stimulation with H+. Sixty-six neurons that did respond to H+ stimulation were uncoupled from respiration, and identified as NR neurons. These neurons presented distinct ranges of H+ sensitivity. The neuronal sensitivity to H+ was mainly assessed by the slope of the stimulus-response curve, where the steeper the slope, the higher the H+ sensitivity. On this basis, NR neurons were classed as being either weakly or highly sensitive to H+. NR neurons with a high H+ sensitivity (n = 12) showed an average value of 34.17 +/- 7.44 spikes s-1 (100 nC)-1 (mean +/- S.D.) for maximal slope and an EC50 of 126.76 +/- 33 nC. Suprathreshold H+ stimulation of highly sensitive NR neurons elicited bursting pattern responses coupled to the respiratory cycle. The bursting responses, which were synchronised with the inspiratory phase and the early expiratory phase of the respiratory cycle, lasted for several seconds before returning to the steady state firing pattern characteristic of the pre-stimulus condition. These NR neurons, which possess the capacity to detect distinct H+ concentrations in the extracellular microenvironment, are excellent candidates to serve in a chemoreceptor capacity in the caudal medulla.

Intravenous and oral antibiotics in respiratory tract infection: an international observational study of hospital practice

BACKGROUND

Hospitalised patients with respiratory tract infections (RTI) frequently receive intravenous (i.v.) antibiotics followed by a short course of oral treatment.

OBJECTIVES

To observe antibiotic use in hospitals in Germany, Spain, France, Italy and the UK and the reasons for choosing the i.v. route and switching to oral treatment.

METHODS

Research pharmacists sought the opinions of physicians and senior nurses in the completion of a semi-structured questionnaire on the treatment of RTI with i.v. antibiotics. Questions focussed on antimicrobials of choice, reasons for choosing i.v., reasons for changing to oral administration, and duration of treatment.

RESULTS

This study recruited 796 patients with RTI, usually pneumonia. Prescribing patterns varied widely between the five hospitals. Accepted clinical criteria were only commonly cited in Germany, Spain and the UK as reasons for choosing the i.v. route at the beginning of the study. These were more commonly cited at the time of switch, although other criteria such as improved condition, were other significant reasons. The mean duration of i.v. treatment ranged from 4 days in the UK to 10 days in Italy, where most patients received the full course of treatment by the i.v. route. Unlike the other hospitals studied, the few patients in Italy who were switched to another form of treatment were as likely to receive intramuscular as oral administration (13% and 11%, respectively).

CONCLUSIONS

The practice of and reasons for prescribing i.v. antibiotics varied in the hospitals studied. Objective clinical criteria were inconsistently cited as reasons for administering i.v. antibiotics and in general these reasons were unrelated to those given for the switch from i.v. to oral administration. In order for guidelines for switching from i.v. to oral antimicrobials to be routinely employed, explicit physiological criteria need to be recorded in a routine fashion. Closer co-operation between pharmacists and physicians may help in developing and implementing guidelines at a local level.

Toxicity to topical dimethyl sulfoxide (DMSO) when used as an extravasation antidote

DMSO is a dipolar, aprotic, hygroscopic solvent for which a large number of pharmacologic properties have been claimed. Topical DMSO is considered an effective and safe antidote to be used with topical cooling after extravasations of vesicant drugs. A case of toxicity after its use as an antidote is described. Furthermore, the increasing importance of DMSO pharmacology, as its use in haematologic patients is spreading, is reviewed.

The Study of Passive Membrane Properties and Morphology Reveals Neuronal Differences Along the Sagittal Axis of the Ventral Periaqueductal Grey Matter

The membrane properties of the neurons located in the ventral part of the periaqueductal grey (PAG) of the guinea-pig were studied using an in vitro slice preparation. Cells had low values of resting membrane potential (-53.3 +/- 1.3 mV, mean +/- standard error), high input resistance (195. +/- 16.2 M ohm) and moderate values of membrane time constant (12.6 +/- 0.7 ms). The last two parameters changed as recordings were made along the sagittal axis, higher values corresponding to the more rostral cells. Three main neuronal types-fusiform, triangular and stellate-were found in the ventral PAG using intracellular injection of Lucifer yellow. A study of the cell number and cell density was carried out in coronal and sagittal sections of the ventral PAG. This analysis showed a clear gradient of size in this region arising from the gradual disappearance of large (17 to 40 microm) neurons in the caudorostral direction. The neuronal density also increased in this direction. Therefore, some electrotonic and morphological parameters differ along the sagittal axis. These findings suggest a larger neuronal heterogeneity of the caudal part of the PAG, and might contribute to a functional segregation of this region.

Gas exchange and pulmonary hemodynamics during lung resection in patients at increased risk: relationship with preoperative exercise testing

STUDY OBJECTIVES

To evaluate the intraoperative evolution of patients with COPD during lung resection and to test whether exercise testing could be helpful in the prediction of the intraoperative course.

DESIGN

Prospective study.

SETTING

University teaching hospital.

PATIENTS

Forty patients (mean [+/- SD] age, 65 +/- 9 years) with COPD (ie, FEV(1), 55 +/- 11% of predicted) and resectable lung neoplasms.

INTERVENTIONS

Preoperatively, pulmonary function testing, quantitative lung perfusion scanning, and exercise performance testing were administered. Intraoperatively, pulmonary, hemodynamic, and blood gas measurements were performed at five stages, including periods of two-lung ventilation (TLV) and periods of one-lung ventilation (OLV).

RESULTS

During OLV, compared with TLV, the PaO(2)/fraction of inspired oxygen (FIO(2)) ratio decreased from 458 +/- 120 to 248 +/- 131 mm Hg (p < 0.05), whereas pulmonary artery pressure (PAP) increased from 18 +/- 5 to 23 +/- 5 mm Hg (p < 0.05). Cardiac output (t) also increased from 4.0 +/- 1.2 to 5.1 +/- 1.9 L/min (p < 0.05), yielding to a higher mixed venous PO(2). Both PaO(2) and t during OLV were significantly lower in patients who had undergone right thoracotomies compared with those who had undergone left thoracotomies. The PaO(2)/FIO(2) ratio during OLV correlated with the PaO(2) during exercise (r = 0.39; p = 0.01) and with the perfusion of the non-neoplastic lung (r = 0.44; p = 0.005).

CONCLUSIONS

In COPD patients, OLV leads to a significant derangement of gas exchange, which is more pronounced in right thoracotomies. Preoperative measurement of PaO(2) during exercise and the distribution of perfusion by lung scan might be useful to identify those patients who are at the greatest risk of abnormal gas exchange during lung resections.

Synthesis, characterization, and magnetic properties of self-assembled compounds based on discrete homotrinuclear complexes of Cu(II)

Three new supramolecular entities of Cu(II) were synthesized and characterized: [(Cu(H(2)O)(tmen))(2)(mu-Cu(H(2)O)(opba))](2)[(ClO(4))(2)](2).2H(2)O (1), [(Cu(H(2)O)(tmen))(2) (mu-Cu(H(2)O) (Me(2)pba))](2)[(ClO(4))(2)](2) (2), and [(Cu(H(2)O)(tmen))(Cu(tmen))(mu-Cu(OHpba))](n)() ((ClO(4))(2))(n)().nH(2)O (3), where opba = o-phenylenbis(oxamato), Me(2)pba = 2,2-dimethyl-1,3-propylenbis(oxamato), OHpba = 2-hydroxy-1,3-propylenbis(oxamato), and tmen = N,N,N'N'-tetramethylethylenediamine. The crystal structures of 1, 2, and 3 were solved. Complex 1 crystallizes in the monoclinic system, space group C2/c with a = 20.572(4) A, b = 17.279(6) A, c = 22.023(19) A, beta = 103.13(4) degrees, and Z = 8. Complex 2 crystallizes in the monoclinic system, space group P2(1)/c, with a = 16.7555(7) A, b = 13.5173(5) A, c = 17.1240(7) A, beta = 104.9840(10) degrees, and Z = 4. Complex 3 crystallizes in the orthorhombic system, space group Pca2(1) with a = 21.2859(4) A, b = 12.8286(10) A, c = 12.6456(2) A, and Z = 4. The three complexes are very similar in structure: a trinuclear Cu(II) complex with the two terminal Cu(II) ions blocked by N,N,N',N'-tetramethylethylenediamine, but with a different environment in the Cu(II) central ion. In the case of complex 1, two of these trinuclear entities are packed with a short distance between the central Cu(II) ions of two separate entities forming a hexanuclear-type compound. In the case of 2, two of these trinuclear entities are linked by a hydrogen bond between a water molecule of one terminal Cu(II) and one oxygen atom of the oxamato ligand of the neighboring entity, also forming a hexanuclear complex. In the case of complex 3, the intermolecular linkages give a one-dimensional system where the OH groups of the OHpba entities are linked to the terminal Cu(II) of the neighboring entities. The magnetic properties of the three complexes were studied by susceptibility measurements vs temperature. For complex 1, an intramolecular J value of -312.1 cm(-)(1) and a contact dipolar interaction of -0.44K were found. For complex 2 and 3 the fit was made by the irreducible tensor operator formalism (ITO). The values obtained were as follows: J(1) = -333.9 cm(-)(1) and J(2) = 0.67 cm(-)(1) for 2 and J(1) = -335.9 cm(-)(1) and J(2) = 3.5 cm(-)(1) for 3.

Pulmonary gas exchange responses to histamine and methacholine challenges in mild asthma

Histamine (HIST) produces greater changes in bronchial and pulmonary vasculature, and so may produce more gas exchange abnormalities, than methacholine (MTH) after inhalational challenge. The goals of this study were to compare the effects of HIST and MTH challenge on pulmonary gas exchange in patients with mild asthma at an equivalent degree of bronchoconstriction. Eleven patients were studied (mean+/-SEM age, 22+/-1 yr; forced expiratory volume in one second (FEV1), 91+/-5% pred) using a randomized, double-blind cross-over design. Respiratory system resistance (Rrs), arterial blood gases, and ventilation-perfusion distributions were measured before and after HIST/MTH challenges when cumulative doses caused a 30% fall in FEV1. Compared with baseline, HIST and MTH provoked similar moderate to severe increases in Rrs (p<0.005 each), and mild to moderate decreases in arterial oxygen tension (Pa,O2) due to ventilation-perfusion abnormalities (dispersion of pulmonary blood flow -log SDQ-, 0.40+/-0.03-0.71+/-0.08 and 0.47+/-0.04-0.89+/-0.06; normal values <0.60-0.65), respectively, similar to those shown in mild to moderate acute asthma, without differences between them. For the same degree of airflow obstruction, both histamine and methacholine bronchoprovocations induce, in patients with mild asthma, very similar disturbances in ventilation-perfusion distribution and respiratory system resistance, suggesting similar mechanisms of airway narrowing.

The use of evidence in pharmacovigilance

OBJECTIVE

Withdrawal of a drug from the market for safety reasons is a serious and sometimes complex decision. The scientific evidence supporting drug withdrawals in the past years is critically appraised.

METHODS

With data provided by the Spanish Medicines Agency, all drugs withdrawn from the Spanish market for safety reasons from January 1990 to December 1999 were identified. The adverse drug reactions (ADRs) were classified by the year of withdrawal, by the organ/system affected and by the alleged type of reaction (Rawlins and Thompson classification). A systematic review of the literature was performed.

RESULTS

A total of 22 drugs were withdrawn from the market due to safety reasons. In 18 of 22 cases (82%), the evidence supporting the drug withdrawal came from individual case reports, cases series or the combination of data provided by randomised clinical trials and case reports. Hepatic (eight cases) and cardiac (five cases) reactions accounted for 59% (13 of 22) of the total withdrawals. In 10 of 22 (45%) cases, drug withdrawal was clearly due to type-B reactions. Only four withdrawals were based on evidence from observational studies including a comparison group.

CONCLUSION

Case reports are the main source of information used to withdraw a drug from the market for safety reasons. It is necessary to improve the quality of evidence supporting the withdrawal process of drugs linked to unexpected and severe ADRs. The use of large databases to perform cohort or nested case-control analyses is the most efficient and reliable method to study type-A class effect ADRs. The implementation of such databases in different countries could increase the quality of the information on ADRs by allowing researchers to conduct efficiently these type of studies.

Synthesis, structure, and magnetic properties of three new one-dimensional nickel(II) complexes: new magnetic model for the first one-dimensional S = 1 complex with alternating ferro-ferromagnetic coupling

Three new one-dimensional nickel(II) complexes with the formulas trans-[Ni(N-Eten)2(mu1.3-N3)]n(ClO4)n (1), trans-[Ni(N-Eten)2(mu1.3-N3)]n(PF6)n (2), and cis-[Ni(N-Eten)(mu1.1-N3)2]n (3) (N-Eten = N-Ethylethylenediamine) were synthesized and characterized. Complex 1 has the P2(1)/c space group and consists of a structurally and magnetically alternating one-dimensional antiferromagnetic system with end-to-end azido bridges. Compound 2 has the P1 space group and has alternate units in its structure but consists of a magnetically uniform one-dimensional antiferromagnetic system with end-to-end azido bridges. Complex 3 has the I2/a space group and may be described as a structurally and magnetically alternating one-dimensional ferromagnetic system with double azido bridged ligands in an end-on coordination mode. The chi(M)T versus T plots for compound 3 suggest an intramolecular ferromagnetic interaction between adjacent NiII ions and metamagnetism at low temperature (below 10 K). The magnetization measurements versus applied field confirm this metamagnetic ordering. In order to describe the magnetic data of this compound we developed a general formula for the magnetic susceptibility of the isotropic ferro-ferromagnetic S = 1 Heisenberg chain in terms of the alternation parameter alpha (= J2/J1); this assumed a variation of chi(M)T versus the length N.

Lack of serological evidence for Mycoplasma fermentans infection in army Gulf War veterans: a large scale case-control study

Mycoplasma firmentans is suspected in the development of 'Gulf War illness' in veterans of Operation Desert Storm. We conducted a matched case-control study for the prevalence of M. firmentans-specific antibodies before and after the operation, as well as seroconversion rates in veterans with and without complaints of 'Gulf War illness'. Cases consisted of Gulf War veterans, who complained of various illnesses and were enrolled in the second phase of the health evaluation by the Army Comprehensive Clinical Examination Program (CCEP). Controls were selected from Gulf War veterans who did not participate in the registry and did not request a health evaluation by the CCEP. Before operation deployment, 34 out of 718 of the cases (48%) and 116 out of 2233 of the controls (5.2%) tested positive for M. fermentans-specific antibodies. There was no difference in rates of seroconversion between cases and controls (1.1 vs. 1.2%) to M. fermentans during Operation Desert Storm. Thus, there is no serological evidence that suggests infectionby M. fermentans is associated with development of 'Gulf War illness'.

[Analysis of the cost-effectiveness relationship in the empirical treatment in patients with infections of the lower respiratory tract acquired in the community]

BACKGROUND

Cost of treatment of community-acquired infections in Spain is an important factor in overall health expenditures. The aim of this study was to assess the direct health costs related with the treatment of patients with community-acquired pneumonia (CAP) and acute exacerbations of chronic bronchitis (AECB) due to infection, using different antibiotic options, and to identify main cost drivers.

METHODS

A basic decision analysis model was developed, including probabilities estimation derived from the literature review, supplemented when needed by the opinion of a panel of 8 Spanish physicians (Delphi technique). Four groups of antibiotics were included (macrolides, beta-lactam, fluoroquinolones and cephalosporins) in two different groups: patients with CAP without hospital admission criteria and patients with AECB due to respiratory infection. The analytic horizon and the perspective used were those of the Spanish National Health Service. Direct cost were assessed (drugs, outpatient visits, hospital admissions, diagnostic tests). Indirect cost were not included in the model. Final costs uses as main outcome measure the average cost per patient treated. All results were calculated following a fold-back technique. Sensitivity analysis were included allowing for variations in several clinically relevant parameters.

RESULTS

1. Patients with CAP: Hospital admissions, directly related to the effectiveness rate of initial empirical antibiotic therapy, were the main cost driver (50%-70%). Acquisition costs of initial antibiotic therapy only account for 2%-13% of total costs. 2. Patients with AECB: Outpatient visits are the main cost driver for these group of patients (49% of total costs). Hospital admission costs are also an important cost driver (40%-51% of total costs). Acquisition costs of initial antibiotic therapy account for 4%-28% of total costs. Clinical effectiveness of first antibiotic option is the main variable regarding the cost-effectiveness rate.

CONCLUSION

The model here presented showed that acquisition costs of first empirical antibiotic therapy are only a small proportion of total costs related with the management of community acquired lower respiratory tract infections in Spain. The clinical effectiveness rate of the first antibiotic used is the main variable which determines the final average cost per patient cured. For patients with lower respiratory tract infections the therapeutic option with a better cost-effectiveness ratio must be chosen, in order to minimize the risk of therapeutic failure after first line therapy, and should not be selected only by its lower acquisition costs.