[Cognitive impairment associated to leukoaraiosis: its pathophysiology, clinical manifestations and treatment]

INTRODUCTION AND DEVELOPMENT

Leukoaraiosis is a radiological term which refers to white matter disturbances observed as a hypodensity in computed tomography and hyperintensity in T2-weighted magnetic resonance image. The most accepted theory to explain the mechanism of production of leukoaraiosis is chronic ischemia, due to a damage in penetrating arteries. It is an entity with increasing interest, since it is associated with the presence of cognitive impairment. Clinical manifestations in relation with cognitive functions range from mild affectation to dementia, affecting the processing speed and executive functions.

CONCLUSIONS

It seems that the control of vascular risk factors slow the progression of leukoaraiosis and cognitive impairment, and although there are no really effective treatment, it seems that some drugs, such as acetylcholinesterase inhibitors or NMDA-receptor antagonists, exert a beneficial effect, although slight, in cognitive functions.

Identification of a plum pox virus CI-interacting protein from chloroplast that has a negative effect in virus infection

The cylindrical inclusion (CI) protein of potyviruses is involved in virus replication and cell-to-cell movement. These two processes should rely on multiple plant-virus interactions; however, little is known about the host factors that are involved in, or that may interfere with, CI functions. By using a yeast two-hybrid system, the CI protein from Plum pox virus (PPV) was found to interact with the photosystem I PSI-K protein, the product of the gene psaK, of Nicotiana benthamiana. Coexpression of PPV CI was shown to cause a decrease in the accumulation level of PSI-K transiently expressed in N. benthamiana leaves. To test the biological relevance of this interaction, we have analyzed the infection of PPV in N. benthamiana plants in which psaK gene expression has been silenced by RNA interference, as well as in Arabidopsis thaliana psaK knockout plants. Our results show that downregulation of the psaK gene leads to higher PPV accumulation, suggesting a role for the CI-PSI-K interaction in PPV infection.

Effects of spinal and peripheral nerve lesions on the intersegmental synchronization of the spontaneous activity of dorsal horn neurons in the cat lumbosacral spinal cord

In the anesthetized and paralyzed cat, spontaneous negative cord dorsum potentials (nCDPs) appeared synchronously in the L3 to S1 segments, both ipsi- and contralaterally. The acute section of both the intact sural and the superficial peroneal nerve increased the variability of the spontaneous nCDPs without affecting their intersegmental coupling. On the other hand, the synchronization between the spontaneous nCDPs recorded in segments L5-L6 was strongly reduced following an interposed lesion of the left (ipsilateral) dorsolateral spinal quadrant and it was almost completely abolished by an additional lesion of the contralateral dorsolateral quadrant at the same level. Our observations support the existence of a system of spontaneously active dorsal horn neurons that is bilaterally distributed along the lumbosacral segments and affects, in a synchronized and organized manner, impulse transmission along many reflex pathways, including those mediating presynaptic inhibition.

Mutant prevention concentration: comparison of fluoroquinolones and linezolid with Mycobacterium tuberculosis

OBJECTIVES

The mutant prevention concentration (MPC) has recently been defined to characterize the capacity for severely restricting the selection of resistant mutants during antibiotic treatment. We determined this parameter for ciprofloxacin, levofloxacin, gatifloxacin, moxifloxacin and linezolid in Mycobacterium tuberculosis clinical isolates in our setting.

METHODS

We determined the antibiotic concentration that prevents the selection of resistant mutants following inoculation with a high mycobacteria inoculum on Middlebrook 7H11 plates with serial dilutions of the antibiotics in 224 M. tuberculosis isolates.

RESULTS

Fifty percent of the strains exhibited values of MPC (MPC(50)) lower than 0.8, 0.6, 0.4, 0.4 and 0.6 mg/L for ciprofloxacin, levofloxacin, gatifloxacin, moxifloxacin and linezolid, respectively. If 90% of the strains are considered (MPC(90)), the values are seen to rise to 2, 1.8, 1, 1.2 and 1.2 mg/L, respectively.

CONCLUSIONS

When we compare this parameter with the drug levels in serum and tissue, it can be seen that ciprofloxacin is the least useful of the fluoroquinolones studied, whereas moxifloxacin appears to be the most active. Linezolid exhibits excellent activity against this microorganism (MPC(90) 1.2 mg/L and AUC 140.3 mg.h/L) and this makes us consider that its usefulness in the treatment of this pathology should be thoroughly evaluated.

Conduction failure of action potentials in sensory sural nerves of undernourished rats

In order to determine possible functional and morphometrical alterations produced by perinatal undernourishment on peripheral nerves, sensory sural nerves from control and undernourished rats of 30 and 90 postnatal days of age were dissected and divided in two segments, one for recording the compound action potential (CAP) and the other for histological examination. Nerves from undernourished animals showed maximal CAP responses of smaller amplitude and area, larger trial-to-trial variability in area, and a significant reduction in axonal myelin sheath thickness than nerves from control animals. It is suggested that perinatal undernourishment produces changes in axonal myelin sheath structure, resulting in severe alterations in the generation and propagation of action potentials (block and/or intermittent conduction) in sensory afferent fibers in the rat.

[Evaluation of a pharmaceutical care program to improve adherence to antiretroviral therapy]

OBJECTIVE

To establish the impact of a pharmaceutical care program on the improvement of adherence to antiretroviral therapy, and on patient immunologic and virologic outcome.

MATERIALS AND METHODS

A multicenter, observational, prospective study in a HIV-infected patient cohort under treatment with antiretrovirals selected by random sampling in 19 Spanish hospitals. The study lasted 12 months, in which the program was applied through a baseline preprocedural visit and 4 quarterly visits. Adherence estimation was based on pill counting. An adherence > or = 90, or > or = 95% was considered adequate (in two time points).

RESULTS

541 patients were included, most of them were males (68.8%) between 20 and 78 years of age. Major risk groups included injecting drug users (43.4%) and heterosexuals (29.4%). Sixty percent had already received treatment for more than 3 years. Mean baseline viral load and CD4 count values were 32,866 copies/ml and 485 cells/mm3, respectively. Throughout the study a slight increase in the percentage of adherent patients was seen; however, statistical significance was not reached (64.3 and 79.2% of patients showed an adherence > 95 and > 90%, respectively, during the fourth quarter, versus 59.8 and 75.5% at baseline). A statistically significant decrease in viral load and increase in CD4 cells was seen following program application. The percentage of patients with a viral load < 200 copies/ml was 72.2, 76.7, and 75.0% at the 2nd, 3rd, and 4th quarters, respectively, versus 64.2% at baseline. CD4 cell counts increased by 50 cells/mm3 on average from the start to the end of follow-up.

CONCLUSIONS

Patients included in the program had a good immunologic and virologic outcome, and a trend towards an increased percentage of patients with good adherence was also seen. These results confirm the need to implement follow-up programs for patients receiving antiretrovirals in order to ensure maximum therapeutic benefits.

[Comparison between two 13C-urea breath tests for the diagnosis of Helicobacter pylori infection: isotope ratio mass spectrometer versus infrared spectrometer]

OBJECTIVES

To compare the accuracy of the breath test using the isotope ratio mass spectrometer (IRMS) versus the nondispersive isotope-selective infrared spectrometer (NDIRS) in the diagnosis of Helicobacter pylori infection.

METHOD

Multicenter study in 4 Spanish hospitals. One group of dyspeptic patients who had not undergone prior eradication therapy and another group of patients with gastric ulcer or gastrointestinal bleeding due to gastroduodenal ulcer receiving H. pylori eradication therapy were included in the study. A reference standard based on histology and the rapid urease test was used. The breast test (TAU-KIT, Isomed S.L., Madrid, Spain) was performed with citric acid and 100 mg of 13C-urea. Samples of expired air were collected in tubes and bags for reading with the IRMS (ABCA, PDZ, Crewe, Manchester, England) and the NDIRS (UBiT-IR200, Otsuka Electronics, Co, Osaka, Japan), respectively. The endoscopist, pathologist and person responsible for reading the urease test and both breath tests were blinded to the results of the other diagnostic methods.

RESULTS

Forty-one patients were included. The prevalence of H. pylori was 26%. No differences were found on comparing the mean values obtained with the IRMS and the NDIRS: 13 (standard deviation) (24) and 14 (25) delta units, respectively. The area under the ROC curve for the IRMS and the NDIRS was 0.96. The diagnostic accuracy for the best cut-off point with the IRMS and the NDIRS was, respectively: sensitivity (90 and 100%), specificity (96 and 89%), positive predictive value (90 and 77%), negative predictive value (96 and 100%), + likelihaod ratio (25 and 9.3) and (0.1 and 0). A close correlation was found between the values of the IRMS and those of the NDIRS (lineal regression equation, Y = 1.1 + 1.004. X; r = 0.97).

CONCLUSION

Both the spectrometers used to evaluate the breath test, the IRMS and the NDIRS, offer a high degree of accuracy in the diagnosis of H. pylori infection.

Intersegmental synchronization of spontaneous activity of dorsal horn neurons in the cat spinal cord

Extracellular recordings of neuronal activity made in the lumbosacral spinal segments of the anesthetized cat have disclosed the existence of a set of neurons in Rexed's laminae III-VI that discharged in a highly synchronized manner during the occurrence of spontaneous negative cord dorsum potentials (nCDPs) and responded to stimulation of low-threshold cutaneous fibers (<1.5x T) with mono- and polysynaptic latencies. The cross-correlation between the spontaneous discharges of pairs of synchronic neurons was highest when they were close to each other, and decreased with increasing longitudinal separation. Simultaneous recordings of nCDPs from several segments in preparations with the peripheral nerves intact have disclosed the existence of synchronized spontaneous nCDPs in segments S1-L4. These potentials lasted between 25 and 70 ms and were usually larger in segments L7-L5, where they attained amplitudes between 50 and 150 micro V. The transection of the intact ipsilateral hindlimb cutaneous and muscle nerves, or the section of the dorsal columns between the L5 and L6, or between the L6 and L7 segments in preparations with already transected nerves, had very small effects on the intersegmental synchronization of the spontaneous nCDPs and on the power spectra of the cord dorsum potentials recorded in the lumbosacral enlargement. In contrast, sectioning the ipsilateral dorsal horn and the dorsolateral funiculus at these segmental levels strongly decoupled the spontaneous nCDPs generated rostrally from those generated caudally to the lesion and reduced the magnitude of the power spectra throughout the whole frequency range. These results indicate that the lumbosacral intersegmental synchronization between the spontaneous nCDPs does not require sensory inputs and is most likely mediated by intra- and intersegmental connections. It is suggested that the occurrence of spontaneous synchronized nCDPs is due to the activation of tightly coupled arrays of neurons, each comprising one or several spinal segments. This system of neurons could be involved in the modulation of the information transmitted by cutaneous and muscle afferents to functionally related, but rostrocaudally distributed spinal interneurons and motoneurons, as well as in the selection of sensory inputs during the execution of voluntary movements or during locomotion.

Validation of the 13c-urea breath test for the initial diagnosis of helicobacter pylori infection and to confirm eradication after treatment

OBJECTIVES

the breath test with 13C-urea (UBT) is a method widely used in Spain, but its diagnostic accuracy has not been evaluated in a clinical trial until now. Our objective was to validate the UBT (TAU-KIT) both as an initial diagnostic method for the detection of H. pylori infection and as a method to confirm eradication.

METHODS

a multi-centre study in 7 Spanish hospitals was performed. A group of dyspeptic patients who had not previously received eradication treatment was included, and a second group of patients with gastric ulcer or upper gastrointestinal bleeding due to peptic ulcer was also included (eradication of H. pylori was confirmed 6 to 8 weeks after treatment completion with omeprazole, clarithromycin and amoxycillin). In both groups an endoscopy was performed with biopsies for histology and rapid urease test. Patients were considered infected if both tests yielded positive results, and not infected when both tests were negative. The UBT 13C-urea (TAU-KIT, Isomed S.L., Madrid, Spain) was performed with citric acid and 100 mg of 13C-urea. The pathologist and persons responsible for endoscopy, urease test and UBT were all unaware of the results from the other diagnostic methods.

RESULTS

in the pre-treatment group (36 patients) the prevalence of H. pylori was 72%, the area under the ROC curve for the diagnosis of infection with the UBT was 0.99, and the best cut-off point was 5 units, with the following results: sensitivity= 96% (95% CI = 81-99%), specificity= 100% (69-100%), positive predictive value (PPV) = 100% (87-100%), negative predictive value (NPV) = 92% (59-100%), likelihood ratio (LR) + = infinity, and LR- = 0.04. In the post-treatment group (85 patients) the prevalence of H. pylori was 16%, the area under the ROC curve was 0.99, and the best cut point was 4.6, with the following results: sensitivity= 100% (77-100%), specificity = 97% (90-99%), PPV = 88% (62-98%), NPV = 100% (95-100%), LR+ = 35, and LR- = 0.

CONCLUSION

UBT provides excellent accuracy both for the initial diagnosis of H. pylori infection and to confirm eradication after treatment.

Multiple sclerosis in the tropics: genetic association to STR's loci spanning the HLA and TNF

Clear evidence has been presented correlating gene polymorphisms at 6p21.3-21.4 (containing HLA and TNF) and the predisposition to acquire multiple sclerosis (MS). In a previous study, we found that polymorphisms at HLA DQAI were associated with being or not being predisposed to MS in individuals inhabiting the tropics, where the prevalence of MS is significantly lower than in subtropical areas. Here, we tested the hypothesis that polymorphisms at D6S276, D6S265, D6S273 and D6S291 microsatellite loci are in strong linkage disequilibrium with a major genetic factor predisposing to MS. These microsatellites span the 6p21.3 region with intervals of 5 cM establishing particular landmarks for the HLA and TNF loci. Thirty-five MS patients and 35 controls, age, sex, social, ethnically and geographically matched healthy individuals, were studied. After testing the fit of gene frequencies to the normal distribution and performing the correlation for multiple comparisons, we found significant differences among the case and the control frequencies for the allele 202 belonging to the marker D6S276 (Pc=0.00455) and for the allele 114 belonging to the marker D6S265 (Pc=0.0084). For these two alleles at different loci, we found higher frequencies in the cases than in the controls. A nonsignificant p value was found in testing the existence of linkage disequilibrium among the studied loci in the cases and in the controls. In conclusion, the current study adds evidence to the established association among polymorphisms of genes located at 6p21.3-21.4 and MS. Furthermore, because of the distribution of the tested microsatellite loci, the more probable critical region could be correlated with the TNF neighborhood.

Chronic exposure of HepG2 cells to excess copper results in depletion of glutathione and induction of metallothionein

Metallothionein (MT) and reduced glutathione (GSH) play an important role in the intracellular handling of copper by preventing the generation and favouring the removal of copper-derived free radicals. The present study addressed the changes in MT and GSH that follow chronic (2 or 5 weeks) exposure of human hepatoblastoma cells (HepG2) to excess copper. Copper treatment (100 microM, 2 weeks) led to a 28-fold elevation in intracellular copper. Concomitantly, cells exhibited a seven-fold increase in total MT and an increment in its saturation with copper from 45 to 86%. Around 38% of copper in the cytosolic fraction could be accounted for by MT. GSH equivalents were substantially lowered (to 37% of basal levels) in treated cells, with only part of it being accounted for by an increase in GSSG. Copper-treatment induced no changes in catalase or GSH-peroxidase activities but it was associated with a small reduction in SOD (20%) and GSH-reductase (26%) activities. Copper-loaded cells did not differ from controls in their basal oxidative tone; however, when exposed to tert-butylhydroperoxide they exhibited a markedly greater susceptibility to undergo both oxidative stress and cell lysis. It is proposed that chronic exposure of HepG2 cells to excess copper is accompanied by "adaptive changes" in GSH and MT metabolism that would render cells substantially more susceptibility to undergo oxidative stress-related cytotoxicity.

Expression of lectin receptors on the membrane surface of sperm of fertile and subfertile boars by flow cytometry

Studies suggest that carbohydrates are important in different stages of fertilization. Plasma membrane changes accompanying in vitro capacitation and acrosome reaction (AR), such as removal or appearance of specific glycoproteins, have been studied using lectins that bind specifically to carbohydrate residues. In specialized artificial insemination farms and semen production centers, identification of boars with decreased fertilization ability (subfertility) is a newborn necessity. This investigation is a sequential study to determine the kinetics of surface carbohydrates turnover during in vitro capacitation and AR in fertile and subfertile boar sperm. Flow cytometry determinations of the binding of three FITC-labeled lectins were assessed. WGA binding was significantly lower in fresh, capacitated, and acrosome-reacted sperm of subfertile boars than in fertile boars. Con-A binding was not significantly different in fresh sperm of fertile and subfertile boars. However. Con-A labeling in capacitated, and acrosome-reacted sperm differed significantly in both groups. UEA binding increased only in capacitated sperm of subfertile boars. These findings could be used as indicators of capacitation and AR and may also be a good indicator of sperm fertilizing ability in boars.

Acrosome reaction in fertile and subfertile boar sperm

The main purpose of sperm evaluation is to predict its fertilizing ability. However, basic sperm test results show a low correlation with fertilizing ability. The purpose of this study was to determine whether there is an association between acrosome reaction (AR) and the incidence of subfertility of normal sperm boar. The production records of 22 farms were analyzed to identify boars with low fertility and/or prolificity, classified as subfertile. Twenty-two subfertile boar semen samples were analyzed and compared with 51 samples of fertile boars. Sperm were capacitated during 4 h at 39 degrees C. viability was determined by bisbenzimide (Hoechst-33258) staining. Acrosome reaction was assessed with fluorescein isothiocyanate conjugated Pisum sativum agglutinin. The percentage of spontaneous acrosome reaction (SAR) was not significantly different in fertile (4.5%) and subfertile boars (4.75%) (p > .05). Nevertheless, the percentage of progesterone-induced acrosome reaction (IAR) was significantly lower in subfertile boars (5.75%) as compared with fertile boars (10%) (p < .01). These results suggest that assessment of IAR in vitro may be a useful parameter to identify subfertility in boars.

Effect of perinatal food deficiencies on the compound action potential evoked in sensory nerves of developing rats

The aim of this study was to analyze the possible alterations produced by inadequate perinatal food intake, in quantity (undernutrition) or quality (malnutrition), on the generation and propagation of the compound action potential (CAP) evoked in sensory sural nerves, during the postnatal development of the rat. Low intensity stimulation (2-3 times the threshold of the most excitable nerve fibers; xT) of the sural nerve evoked an early potential (CAP-A component) which is due to activation of low-threshold, fast-conducting myelinated group A afferent fibers. Meanwhile, at higher stimulus intensity (20-30T) it produced a second, long-lasting potential (CAP-C component) probably due to activation of high-threshold, slow-conducting group Adelta or C afferent fibers. Compared to control nerves, the CAP-A component, but not the CAP-C component of undernourished and malnourished nerves showed significant changes in amplitude, area, electrical threshold and conduction velocity (except absolute refractory period) at several postnatal ages. Our results may suggest that a relative large number of myelinated group A afferent fibers in the sural nerve of undernourished and malnourished animals suffer severe alterations on their electrophysiological properties of generation and propagation of the action potential during the postnatal development of the rat.

Clinical features of multiple sclerosis in a genetically homogeneous tropical population

Individuals affected with multiple sclerosis (MS) from a genetically homogeneous Caucasian population in Antioquia, a tropical region of Colombia, were evaluated in order to observe the clinical behavior of the disease. The frequency of clinical manifestations in 65 patients with definite MS from Antioquia was compared with those reported from temperate regions. The most common manifestations were optic neuritis and motor symptoms with absence of cerebellar symptoms. This presentation is significantly different from the frequency distribution at onset in series from temperate regions. These differences suggest that environmental factors could modify the clinical expression of MS in this population.

[Internal jugular phlebectasia]

The jugular phlebectasia is an infrequent anomaly in which a jugular dilatations of the jugular vein during the Valsalva manoeuvre is the main characteristic. We report a case of a 7 years old male with an internal jugular phlebectasia manifestating as a latero-cervical right mass expanding with Valsalva manoeuvre. After the first initial echographic study, we recommend angio-TAC helicoidal as an useful test to confirm the diagnosis, it is also useful to get a tridimensional reconstruction of the jugular anomaly as well as establish the extension and possible complication. Jugular phlebectasia is a benign entity, usually it doesn't progress and causes a minimal estatic defect, therefore it is recommended to avoid any surgical resection or drapping. Periodical follow up is the best choice.

[Prevalence of multiple sclerosis in Colombia]

INTRODUCTION

Multiple sclerosis (MS) is the commonest demyelinating condition of the nervous system. It is characterized by numerous demyelinating areas or plaques of demyelination which are found dispersed throughout the nervous system. It has been shown that MS is less frequent in tropical regions than in subtropical regions. In Latin America particularly, there are some studies which show this phenomenon. However, in Colombia no studies of prevalence of MS have been done.

OBJECTIVE

To determine the prevalence of multiple sclerosis in five provinces of Colombia (Antioquia, Caldas, Santander, Risaralda and Bolivar).

PATIENTS AND METHODS

The capture-recapture method was used for two sources to determine the number of cases defined on the criteria of Poser et al seen between July 1995 and June 2000.

RESULTS

The prevalence (cases of MS per 100,000 inhabitants) varied between 1.48 in Antioquia (95% CI 1.12; 1.78) and 4.98 in Risaralda (95% CI 3.52; 6.43). Seventy two percent were women. The regions included in this study represented 25% of the population of Colombia.

CONCLUSIONS

There is a low prevalence of MS which is as expected in tropical areas. Persons with MS in these regions may be very useful in the study of other factors involved in the aetiology of MS (genetic). The capture-recapture method is an excellent tool for carrying out prevalence studies since it is cheap and requires little time.

Integrative medicine: a paradigm shift in medical education and practice

The use of alternative/complementary medicine has been increasing considerably. Conventional medicine must begin to address issues related to the use, safety, regulation, research and education of alternative/complementary medicine. Integrative medicine combines conventional medicine and alternative complementary practices. Integrative medicine is an innovative approach to medicine and medical education. It involves the understanding of the interaction of the mind, body and spirit and how to interpret this relationship in the dynamics of health and disease. Integrative medicine shifts the orientation of the medical practice from disease based approach to a healing based approach. It does not reject conventional medicine nor uncritically accepts unconventional practices. Integrative medicine is an effective, more fulfilling human approach to medicine based on the benefit of the patient by following good medicine practices in a scientific manner.