LUMO energy of model compounds of bispyridinium compounds as an index for the inhibition of choline kinase

Eleven derivatives of 1,1'-[1,2-ethylenebis(benzene-1,4-diylmethylene)]bis(4-pyridinium) dibromides bearing various groups at C-4 of the pyridinium moiety were synthesized and examined for their inhibition of choline kinase (ChoK) and antiproliferative activities. The C-4 substituents include electron-releasing, neutral or electron-withdrawing groups. A one-parameter regression equation has been derived which satisfactorily describes the ex vivo inhibitory potency of ChoK of the title compounds. The electronic effect plays a critical function in the ex vivo inhibition of ChoK although the role of electrostatic interactions could be altered due to a solvation process of both ChoK and ligands.

Lung cancer risk in iron and steel foundry workers: a nested case control study in Asturias, Spain

BACKGROUND

Workers of iron and steel foundries have a high lung cancer risk but the findings on specific processes associated with this risk are inconsistent. We examined the risk of lung cancer among workers in the main industrial processes of a large iron and steel foundry in Asturias, Spain.

METHODS

We conducted a nested case-control study comprised of 144 male lung cancer cases and 558 controls, selected from a study base of about 24,400 workers employed in the industry between 1952 and 1995. Cases were identified through linkage of industry records with those of two cancer registries. Controls were selected through industry records using incidence density sampling, were matched to cases by age and date of birth and had to be alive and without lung cancer at the time of selection. Smoking history was obtained through company medical records. Unconditional logistic regression was applied and all ORs were adjusted for age and tobacco consumption.

RESULTS

Workers were, on an average, heavy smokers and a very strong relation was observed for smoking (OR for "ever smoker" = 32.4). Workers having ever been employed in the blast furnace had an excess lung cancer risk (OR = 2.55, 95% CI 1.25-5.21) compared to a reference group of workers not employed in metal producing departments. A similar excess was observed for workers having as their longest held job employment in the blast furnace. A two-fold risk was also observed for workers in the main foundry. For subgroups of workers, tobacco smoking appeared to be an important positive or negative confounder.

CONCLUSIONS

In this large Spanish foundry, a high risk was observed for workers employed in departments with high exposure to crystalline silica, PAHs, and various other carcinogenic chemicals. Although comparisons were made between workers of the same industry, smoking habits differed and adjustment by smoking modified considerably the risk estimates.

Canine visceral leishmaniasis on Margarita Island (Nueva Esparta, Venezuela)

The frequency of American visceral leishmaniasis affecting humans on Margarita Island, Venezuela, has increased in recent years, and infected dogs appear to constitute the principal source of infection. ELISA tests with Leishmania donovani promastigotes and rK39 antigen from L. chagasi in serum from 541 dogs were positive in 33.1% and 21.6% of the samples, respectively. A second blood sample taken from 50 animals after 8-10 months revealed an increase from 24% to 40% of ELISA positivity to both antigens, suggesting high susceptibility and transmission in the canine population. Among 42 serologically positive dogs, 33% of which showed clinical signs of disease, 79% were positive in polymerase chain reactions using primers specific for the L. donovani complex. Control measures including epidemiological hypersurveillance, the humane sacrifice of infected dogs, and rapid diagnosis and treatment of human cases have been initiated.

QSAR of 1,1'-(1,2-ethylenebisbenzyl)bis(4-substitutedpyridinium) dibromides as choline kinase inhibitors: a different approach for antiproliferative drug design

Ten new structures of a series of the title compounds were synthesized and screened for their activity to inhibit choline kinase under ex vivo conditions. Their inhibitory potency correlates with the 13C chemical shifts (in CD3OD) of the methylene group bearing the positively charged nitrogen. The inhibitory effect on proliferation against the HT-29 cell line is strongly dependent on its ability to inhibit the production of phosphorylcholine.

Health services accessibility among Spanish elderly

The paper aims to identify the variables that best explain the use of health services by people aged 65 and over in Spain. The data comes from the 1993 Spanish National Health Survey (ENSE 93). The conceptual framework is the model proposed by Andersen, who suggests that utilisation is a function of predisposition to use the services, the ability to use them and of need. A bivariate and multivariate analysis (SPSS-X Discriminant Procedure) is conducted to define the predictors that best discriminate users and non-users. The use of each health service is explained by a different set of variables. The need variables play a more important role in predicting the use of non-discretionary services that are more closely related to healing processes (medical consultations, emergencies and hospitalisation). The predisposing and enabling variables are more relevant in explaining the use of dental services, indicating a certain degree of inequity of these discretionary services.

Particle-induced X-ray emission and scanning electron microscopic analyses of the effects of CO2 laser irradiation on dentinal structure

OBJECTIVES

The purpose of this study was to analyze the physico-chemical changes present on the dentinal surface after using CO2 laser irradiation, and to determine whether or not it is possible to seal the dentinal tubules.

METHODS

Thirty human-extracted first premolars were obtained for this study. A Class V cavity was prepared on the buccal surface of all the specimens with a carbide pear-shaped bur, using a conventional high speed handpiece. Fifteen premolars (experimental group) were irradiated with a CO2 laser (with a wavelength of 10.6 microm, 2 W, 10 J, 0.2 s, 25 pulses). The remaining 15 premolars were used as the control group.

RESULTS

Scanning electron microscopy showed that the effect of laser energy on dentin varied from charring, cratering, poring, fissuring, fracturing and cracking up to melting; also, the dentinal tubules were not sealed, in contrast with the control group in which the dentinal surfaces were more homogeneous. Particle-induced X-ray emission results showed that the irradiated dentinal surface presented a decrease in calcium content and an increase in phosphorous content, possibly due to a vaporization process which occurred during the irradiation.

CONCLUSION

The physicochemical changes observed on the irradiated dentinal surface suggest that changes in the hydroxyapatite crystal structure take place, and that these structural changes may be responsible for the observed effects.

[The EMECAM protocol: an analysis of the short-term effect of air pollution on mortality. Estudio Multicéntrico Español sobre la Relación entre la Contaminación Atmosférica u la Mortalidad]

The aim of this study is to Mortality show the protocol of analysis which was set out as part of the EMECAM Project, illustrating the application thereof to the effect of pollution has on the mortality in the city of Valencia. The response variables considered will be the daily deaths rate resulting from all causes, except external ones. The explicative variables are the daily series of different pollutants (black smoke, SO2, NO2, CO, O3). As possible confusion variables, weather factors, structural factors and weekly cases of flu are taken into account. A Poisson regression model is built up for each one of the four deaths series in two stages. In the first stage, a baseline model is fitted using the possible confusion variables. In the second stage, the pollution variables or the time legs thereof are included, controlling the residual autocorrelation by including mortality time lags. The process of fitting the baseline model is as follows: 1) Include the significant sinusoidal terms up to the sixth order. 2) Include the significant temperature or temperature squared terms with the time lags thereof up to the 7th order. 3) Repeat this process with the relative humidity. 4) Add in the significant terms of calendar years, daily tendency and tendency squared. 5) The days of the week as dummy variables are always included in the model. 6) Include the holidays and the significant time lags of up to two weeks of flu. Following the reassessment of the model, each one of the pollutants and the time lags thereof up to the fifth order are proven out. The impact is analyzed by six-month periods, including interaction terms.

Two groups of TH-like immunoreactive neurons in the frog (Rana pipiens) retina

The morphology and distribution of TH-like immunoreactive (TH-IR) cells in the retina of Rana pipiens were studied in retinal whole mounts and in radial and horizontal sections. A large majority (96%) of the immunoreactive cells were found in the inner nuclear layer while a few cells were found in the ganglion cell layer. All TH-IR cells had round to oval somata with average diameter of 10 microm. The 2-4 primary processes of these cells distributed extensively to sublamina 1 of the inner plexiform layer (IPL) and sparsely to sublamina 5. Two groups of TH-IR cells were distinguished: one, designated thin cells, had only thin (<2 microm diameter) primary processes; the second, designated thick cells, had one or more primary processes with diameter(s) exceeding 2 microm for a distance of 5 microm or more from the soma. The thin cells did not significantly differ from the thick cells in soma diameter, number of primary processes, horizontal spread of processes or vertical lamination of processes. Nearest neighbor analyses of the two types revealed that the population of TH-IR cells (thick and thin together) have an orderly distribution while the thick cells alone are more randomly distributed, indicating that the thick cells do not comprise a functional population. The total number of TH-IR cells varied between retinas; the variability was due principally to variation of thin cell density. It is hypothesized that the thick cells are a subpopulation of the TH-IR cells which are in a particular physiological state at the time of fixation.

Capillary electrophoretic method for quality control of phospholipid products

A practical, low cost capillary electrophoretic method for phospholipid products employed in pharmaceutical, cosmetic and food industries with quality control purposes is described. The phospholipid components of the samples were hydrolyzed prior to their electrophoretic separation. The carrier electrolyte to determine choline, ethanolamine and serine consisted of 5 mM imidazole, pH 3.0 using indirect UV detection at 214 nm. Inositol was quantified employing a buffer of 40 mM sodium borate, pH 10.0 at 40 degrees C and detection at 185 nm. Analytical parameters were evaluated and the results obtained of phospholipid composition in commercial samples from soybeans and animal sources showed acceptable values.

Infraclavicular brachial plexus block effects on respiratory function and extent of the block

BACKGROUND AND OBJECTIVES

Axillary block is devoid of severe respiratory complications. However, incomplete anesthesia of the upper limb is the main disadvantage of the technique. Theoretically, the more proximal infraclavicular approach would produce a more extensive block without the risk of pneumothorax. However, neither its effects on respiratory function nor a detailed characterization of the extent of neural block has been assessed. The goal of this study was to evaluate the possible changes in respiratory function and also the extent of the block after infraclavicular block.

METHODS

We performed an infraclavicular block with a mixture of 40 mL 1.5% plain mepivacaine and 4 mL 8.4% sodium bicarbonate in 20 patients. Forced expiratory volumes were measured before and 15 minutes after the injection of local anesthetic, and sensory and motor block were evaluated at 10 and 20 minutes.

RESULTS

We did not find significant differences from baseline in the forced expiratory volumes in any of the patients. Axillary and musculocutaneous nerve distributions had the lowest rate of sensory block at 20 minutes.

CONCLUSIONS

Infraclavicular block does not produce a reduction in respiratory function.

The proliferative response of HIV+ T-cells (CD4+ and CD8+) are severely suppressed via CD28 coactivation

Several studies have suggested that regulation of expression of the costimulatory molecule CD28 on the T-cell surface may play an important role in AIDS pathogenesis. In a study of T-cells from HIV+ donors, we find that activation with anti-CD3 plus anti-CD28 results in a mitogenic response which was approximately 86% suppressed for both CD4+ and CD8+ T-cells when compared to normal control cells. With PMA costimulation (instead of anti-CD28), the anti-CD3 response was suppressed much less, by 64 and 61%, respectively. With Con A as opposed to CD3 stimulation, the degree of suppression was less with either coactivator but still more severe with CD28 than with PMA coactivation. It has been reported that the CD28 subset of CD8+ T-cells is diminished in HIV+ individuals and could account for these results. It is possible as well that the CD28 costimulatory pathway in the CD4+ T-cells particularly is altered due to intervention by the HIV. While our data do not differentiate between these two possibilities, it show that the immune status is compromised in the HIV+ individual not only in terms of number of CD4+ T-cells, but in their activation response as well.

Iopentol (Imagopaque 300) compared with iopromide (Ultravist 300) in abdominal CT. A multi-centre monitoring trial assessing adverse events and diagnostic information--results from 518 patients in Spain

OBJECTIVES

Iopentol (Nycomed Imaging AS, Oslo, Norway) and iopromide (Schering AG, Berlin, Germany) are low-osmolar, non-ionic, iodinated contrast media (CM) used in abdominal CT examinations. The intravenous safety profile and radiological efficacy of iopentol and iopromide were studied in 518 patients. Specifically, frequency of adverse events (AEs), subjective change in quality of diagnostic information, and quantitative enhancement characteristics were compared.

MATERIALS AND METHODS

A prospective, double-blind, randomized, multicentre, parallel-group study was conducted at 8 hospitals. Patients received 100 ml of either iopentol 300 mg I/ml or iopromide 300 mg I/ml.

RESULTS

The incidence of patients with AEs was statistically significantly lower in the iopentol group compared to the iopromide group (2.3% vs. 8.9%, p < 0.001). Discomfort was frequent in both groups (44.8% vs. 49.4%, p = 0.33), sensation of heat and warmth being most common. Overall, diagnostic information was similar in both groups. Both CM gave high percentages of examinations rated as optimal (87.1% vs. 90.5%, p = 0.34) and in which diagnostic confidence was increased (87.5% vs. 91.1%, p = 0.22). No significant differences between the two CM were found concerning quantitative enhancement characteristics.

CONCLUSIONS

In this study iopentol was significantly safer than iopromide for contrast enhanced CT examination of the abdomen. Radiological efficacy was similar with both CM.

13C NMR spectroscopic and X-ray crystallographic study of the role played by mitochondrial cytochrome b5 heme propionates in the electrostatic binding to cytochrome c

The role played by the outer mitochondrial membrane (OM) cytochrome b5 heme propionate groups in the electrostatic binding between OM cytochrome b5 and horse heart cytochrome c was investigated by 13C NMR spectroscopy and X-ray crystallography. To achieve these aims, 13C-labeled heme OM cytochrome b5 was expressed in Escherichia coli as previously described [Rivera M., Walker, F.A. (1995) Anal. Biochem. 230, 295-302]. Assignment of the resonances arising from the heme propionate carbons in ferricytochrome b5 was carried out by a combination of one- and two-dimensional NMR experiments. Titrations of [13C]heme-labeled OM cytochrome b5 with horse heart cytochrome c were carried out in order to monitor the resonances arising from the heme propionate carbonyl carbons in OM cytochrome b5. The results from these titrations clearly show that only the heme propionate located on the exposed heme edge in OM cytochrome b5 participates in the electrostatic stabilization of the complex between OM cytochrome b5 and horse heart cytochrome c. Similar experiments carried out monitoring 13C resonances arising from several other heme substituents demonstrated that the stoichiometry of the complex is 1:1. A conditional binding constant, K which equals 3.8 x 10(4) +/- 1.4 x 10(4) at mu = 0.02 M, was obtained for the formation of the complex by fitting the binding curves obtained experimentally to a model based on this stoichiometry. The X-ray crystal structure of rat liver OM cytochrome b5 solved to 2.7 A resolution shows that the structures of bovine liver microsomal cytochrome b5 and rat liver OM cytochrome b5 are almost identical when compared at medium resolution. The similarity between the two structures, combined with the findings that only the heme propionate located on the exposed heme edge of OM cytochrome b5 participates in the electrostatic binding to cytochrome c and that the stability of this complex is similar to that measured for the association between microsomal cytochrome b5 and cytochrome c, clearly indicates that the site of interaction on OM cytochrome b5 is almost identical to the one elucidated for microsomal cytochrome b5. It is therefore possible to conclude that the large body of information gathered by many investigators for the nonphysiological interaction between microsomal cytochrome b5 and cytochrome c (recently reviewed) [Mauk, A. G. Mauk, M. R., Moore, G. R., & Northrup, S. H. (1995) Bioenerg. Biomembr. 27, 311-330] has indeed biological as well as pedagogical validity.

The IgG isotypes of specific antibodies in patients with American cutaneous leishmaniasis; relationship to the cell-mediated immune response

American cutaneous leishmaniasis (ACL) presents a spectrum of clinical and immunological manifestations. Since the nature of the cellular response appears to play a fundamental role in determining the characteristics of the immunoglobulin isotype of specific antibody responses, we have compared the relative levels of specific antibodies of the four IgG isotypes against Leishmania in sera from patients with different clinical manifestations of ACL. Using a specific antibody capture assay, significant levels of antibodies of the IgG1, 2 and 3 isotypes were detected in localized cutaneous leishmaniasis (LCL); the average level of IgG4 antibodies was low and they were not detected in 10/20 sera. Sera from muco-cutaneous leishmaniasis (MCL) gave a comparatively strong IgG1 response. Sera from diffuse cutaneous leishmaniasis (DCL), the rare form characterized by antigen-specific anergy of cell-mediated immunity, showed highly significant levels of IgG4 antibodies compared to antibody levels of this isotype in the other groups; IgG1 and IgG2 levels were also elevated. Based on other studies of the relationship between the IgG isotype response and cell-mediated immunity, these results confirm a Th1-like CD4+ T cell response in LCL and MCL and a significant Th2-like response in DCL.

Determination of noscapine, hexylresorcinol and anethole in cough lozenges by liquid chromatography

A liquid chromatographic method was developed for the simultaneous separation and determination of noscapine hydrochloride, hexylresorcinol and anethole in cough lozenges. Analysis was performed on a phenyl column with phosphate buffer- acetonitrile as mobile phase and the separated components were detected at 282 mm. Recoveries obtained for the analytes were of 94.6% for noscapine hydrochloride, 99.1% for hexylresorcinol and 96.3% for anethole. The values of the relative standard deviation were 0.8% for noscapine hydrochloride, 1.5% for hexylresorcinol and 1.1% for anethole. The analytical method was validated and a system suitability test was accomplished for the chromatographic method.

[Thrombosis from prosthetic materials: prevention with different antiaggregatory agents. Low dose aspirin?]

Using an ex vivo shunt in dogs, platelet deposition on 6 prosthetic materials used in the construction of cardiovascular prostheses [highly porous Knitted Dacron (intervascular HP 800, 1,400 ml/cm2/min/120 mmHg), Woven Dacron of low porosity (intervascular LP 200, 200 ml/cm2/min/120 mmHg), Doble Velour Knitted Dacron, Avcothane 51 elastomere and the mesothelial and epipericardial surfaces of bovine pericardium] was quantified. The study of the prevention of platelet thrombi formation on these materials was carried out in 6 groups of 8 animals: group 1 (control), group 2 (5 mg/kg body weight/day acetylsalicylic acid), group 3 (20 mg/kg body weight/day acetylsalicylic acid), group 4 (15 mg/kg body wt/day triflusal plus 5 mg/kg body wt/day dipyridamole), group 5 (15 mg/kg body wt/day triflusal) and group 6 (5 mg/kg body wt/day acetylsalicylic acid plus 5 mg/kg body wt/day dipyridamole). Platelets were labeled with 111In-oxine. The least thrombogenic material was Avcothane 51 elastomere. The only effective treatment for reduction of platelet deposition on the 6 materials was that used in group 2. The treatment used in group 3 only decreased the deposition of platelets on 3 of the 6 materials. The treatments employed in groups 4, 5 and 6 did not significantly diminish the deposition of platelets on any of the materials when compared with the control group. The platelet count was not modified in the animals in groups 2 and 4 while in the rest it decreased after the test.