Visual system's adjustments to illuminant changes: heuristic-based model revisited

This study evaluates the effect of illuminant changes along the two post-receptoral mechanisms: red-green (L - 2M) and yellow-blue (L + M - S). By means of a CRT colour monitor, Mondrian-type scenes were simulated and a series of asymmetric colour matches were made with five test illuminants. The standard objects comprising the scenes were simulations of surfaces under equal-energy illuminant and were selected according to lines of equal excitation of the red-green and the yellow-blue mechanisms. Results show that observers' matches are well predicted by assuming affine transformations between test and standard illuminant conditions. The best linear fits derived from the data corroborates the previous heuristic-based algorithms [Zaidi Q. (1998) Journal of the Optical Society of America A. 7. 1767-1776] although some discrepancies were found. Results along red-green mechanism confirm that the significant effect of the illuminant is an additive change along this axis, while data for yellow-blue mechanism suggest that illuminant induces not only multiplicative changes along this axis but additive too. In addition, we found that memory factors involved in the experiment could influence the observers' matches and would be taken into account as responsible of the differences found between the yellow-blue and the red-green systems.     

Antiviral activity of Spirulina maxima against herpes simplex virus type 2

Spirulina has been used in a variety of practical applications in biotechnology and medical sciences. This paper presents the antiviral activity found in a hot water extract (HWE) of a commercial preparation of Spirulina maxima, studied by a microplate inhibition assay, using several viruses. The HWE inhibited the infection for: herpes simplex virus type 2 (HSV-2), pseudorabies virus (PRV), human cytomegalovirus (HCMV), and HSV-1, and the 50% effective inhibition doses (ED(50)) were 0.069, 0.103, 0.142, and 0.333 mg/ml for each virus, respectively. For adenovirus the inhibition was less than 20%, and no inhibition was found for measles virus, subacute sclerosing panencephalitis virus (SSPE), vesicular stomatitis virus (VSV), poliovirus 1 and rotavirus SA-11, at concentrations of 2 mg/ml of the HWE. The highest antiviral activity was for HSV-2, with a selectivity index of 128. The antiviral activity was not due to a virucidal effect. Herpesvirus infection was inhibited at the initial events (adsorption and penetration) of the viral cycle. To initiate the isolation and identification of the compound that exhibits the antiviral activity of S. maxima, some extracts made by using several solvents with different polarity were evaluated by microplate inhibition assay using HSV-2. The highest antiviral activity was detected in the methanol-water 3:1, which suggests that the antiviral activity is probably due to highly polar compounds.     

Treatment of excessive daytime sleepiness in patients with Parkinson's disease with modafinil

Excessive daytime sleepiness (EDS) may limit the symptomatic treatment of Parkinson's disease and can alter the patient's lifestyle significantly. Ten consecutive patients with Parkinson's disease on various dopaminergic drugs and EDS were recruited to a 4-week open-label trial of modafinil. Patients were evaluated using the Epworth Sleepiness Scale and Unified Parkinson's Disease Rating Scale part III. All but three patients, with previous history of intolerability of a dopamine agonist caused by EDS, remained on their baseline medications. Modafinil was titrated as needed to a maximum of 400 mg/day. The mean Epworth Sleepiness Scale score at baseline of patients completing the study (n = 9) was 14.22 (+/- 3.03). After completing the study on an average dose of 172 mg/day, the Epworth Sleepiness Scale score was 6.0 (+/- 4.87). Unified Parkinson's Disease Rating Scale scores were not affected by this medication. Side effects encountered were headache, generalized paresthesias, and hallucinations (n = 1 each, the patient developing hallucinations dropped out of the trial before completing 4 weeks of the study drug). The three patients who did not tolerate any increments of dopamine agonist before modafinil were able to tolerate further upward titration of the dopamine agonist. Modafinil may be effective in reducing EDS in patients with Parkinson's disease treated with dopaminergic drugs. It does not seem to worsen parkinsonian symptoms and may allow further increase in dopaminergic therapy in patients previously unable to tolerate this because of EDS.     

Mutagenesis in Escherichia coli K-12 mutants defective in superoxide dismutase or catalase

Escherichia coli K-12 strains with diminished levels of superoxidedismutase (SOD) due to inactivation of the sodA, sodB or sodAsodB genes were constructed in order to quantify the role ofO^–₂. in mutagenesis. Mutagenesis was monitored by selectingforward mutations to L-arabinose resistance (Ara^R). No sodAsodB mutant inability to grow in aerobic minimal medium wasfound, in contrast to that previously reported for a differentE.coli wild-type genetic background. The role of SOD for copingwith the damaging effects of superoxide became evident afterthe increase in intracellular O^–₂. flux by growing cellsunder hyperoxygenation, but particularly by using redox cyclingcompounds such as plumbagin, paraquat and menadione. Bacteriacompletely devoid of SOD activity showed very high levels ofAra^R-induced mutants at doses that were non-mutagenic for theSOD-proficient parental or the sodA or sodB single mutants.The mutagenicity of nifurtimox and quercetin were studied tofurther compare the responses of the SOD-deficient bacteriato those of their SOD-proficient counterparts. The relativeimportance of SOD and catalase for coping with the damagingeffects of O^–₂. and H₂O₂ was quantified by comparing SOD-deficientbacteria with isogenic catalase-deficient cells (a katG katEdouble mutant). The mutagenicities of plumbagin and menadionewere much higher in SOD-deficient than in catalase-deficientbacteria, in agreement with the role of the O^–₂. radicalin the so-called metal-catalyzed Haber—Weiss reaction.The relevance of catalase in protecting against the damagingeffects of H₂O₂ was evident from the hypersensitivity of thekatG katE double mutant to the mutagenic and lethal effectsof this oxidizing agent. It is concluded that the Ara mutagenicityassay combined with depletion in specific antioxidative enzymescould be a tool in establishing the extent to which DNA damageby oxygen radicals is relevant to mutagenesis.     

Efficacy of telephone and mail intervention in patient compliance with antihypertensive drugs in hypertension. ETECUM-HTA study

OBJECTIVE: To study the efficacy of telephone and mail intervention in therapeutic compliance among patients with mild to moderate hypertension. DESIGN: A prospective controlled multicenter clinical trial. SETTING: Eighty-five primary care centers in Spain, with a duration of 6 months. PATIENTS: A total of 636 patients with newly diagnosed or uncontrolled hypertension were included. Interventions. The patients were randomized and distributed between the following groups: (i) control (CG) - under routine clinical management; (ii) mail intervention (MIG) - received a mailed message reinforcing compliance and reminding of the visits (15 days, 2 and 4 months); (iii) telephone intervention (TIG) - received a telephone call at 15 days, then at 7 and 15 weeks. MAIN OUTCOME MEASURE: Five visits were scheduled, with the measurement of blood pressure and counting of tablets. Compliers were defined as subjects showing 80-110% drug consumption. Calculations were made of mean percentage compliance (MPC) and compliers, mean blood pressure and percentage controlled subjects. RESULTS: Five hundred and thirty-eight patients completed the study (261 males); 85.5% were compliers (CI = 82.5-88.5; n = 460). The MPC was 95.1+/-19.6% (CI = 93.28-96.92). The CG consisted of 182 individuals, MIG = 172 and TIG = 184. Compliers represented 69.2% of the CG (CI 62.5-75.9%), 91.3% (CI = 87.1-95.5) of the MIG (p = 0.0001) and 96.2% of the TIG (CI 93.5-98.9%); the final MPC was 89.6%+/-15 in CG, 96.6%+/-12 in MIG and 99.1+/-26.8 in TIG (p = 0.0001). The percentage of controlled subjects was 47.2% in CG (CI = 40-54.4), 61.3% in MIG (CI = 54.1-68.5%) and 63.3% in TIG (CI = 56.4-70.2%) (p<0.05). CONCLUSIONS: TIG and MIG are effective measures for improving patient compliance in hypertension.     

Hypothalamic adipic hypernatraemia syndrome with normal osmoregulation of vasopressin

Adipsic hypernatraemia is an uncommon disorder in childhood caused by a defect in the osmoregulation of thirst, leading to impairment of water homeostasis and chronic hyperosmolality of body fluids. Adipsia is often associated with an abnormality in osmoregulated vasopressin secretion due to the close proximity of the hypothalamic osmoreceptors that control thirst with those regulating vasopressin secretion. Hypothalamic lesions of diverse aetiology (vascular abnormalities, neoplasms, granulomatous diseases, trauma etc.) have been described in this syndrome. We report a 12-year-old boy with evident weight loss due to hypernatraemic dehydration with a selective defect in osmoregulation of thirst and normal vasopressin secretion with no demonstrable structural lesion. To date, only six paediatric patients with this condition have been described in the literature. Conclusion:hypothalamic adipsic hypernatraemia syndrome must be suspected when a dehydrated patient denies thirst. The study of antidiuretic function is necessary because the osmoregulation of vasopressin secretion could be altered.Abbreviations ADH antidiuretic hormone - AVP arginine vasopressin - Posm plasma osmolality     

Upper urinary tract tumor: differential diagnosis by radiological images

To perform the adequate treatment of upper urinary tract lesions it is very important to have an exact diagnosis. When the suspicion of an upper tract urothelial tumor is established the initial evaluation is carried out by imaging diagnostic tests (intravenous urography, pyelography, and others). The association of radiological tests and urine cytologies allows us to get to a correct diagnosis in most cases. Upper urinary tract endoscopy solves some equivocal cases, but sometimes it is impossible to clarify the nature of the lesion in spite of a comprehensive diagnostic effort. Therapeutic decision should be individualized in these cases. The objective of this article is to describe the various features of upper tract urothelial tumors in a variety of available imaging tests, and to review all conditions that may have similar images, describing the characteristic radiological findings for each of them. We discuss about differential diagnosis and perform a critical evaluation of the diagnostic difficulties that occasionally present upper urinary tract diseases.     

Can Early Diagnosis of Symptomatic Colorectal Cancer Improve the Prognosis?

Patients with colorectal cancer continue to present with relatively advanced tumors. Delay in diagnosis is often believed to have been a contributing factor, and the validity of this hypothesis has seldom been questioned. The aim of this study was to establish whether a delay in diagnosis is related to long-term survival and if the most frequent symptoms were related to the stage or time at which the carcinoma was diagnosed. Data from 660 patients surgically treated for uncomplicated colorectal carcinoma in our institution between 1985 and 2000 were analyzed retrospectively. Age, sex, initial symptoms, duration of symptoms, neoplasm location, curative surgery, TNM stage, and survival time were the variables recorded. Patients were classified into two groups according to symptom duration: < 3 months versus 3 months. Comparative statistical analysis was performed for the two groups as well as the initial symptom, TNM stage, and survival time. Also, the initial symptoms most frequently reported were compared with the TNM stage. The two groups were found to be equal with regard to distribution of age, gender, location of the neoplasm, type of surgery performed, and TNM stage. We found that symptom duration was shortened in the presence of abdominal pain (p = 0.002) [odds ratio (OR) 0.53; 95% confidence interval (CI) 0.35–0.80] and was delayed in the presence of an anemic syndrome (p = 0.006) (OR 2.4; 95% CI 1.27–4.56). Also, the stage of the neoplasm was related to rectal bleeding (p < 0.001) and abdominal pain (p = 0.008). The log-rank test indicated that duration of symptoms was not related to long-term survival (p = 0.90). We concluded that the duration of colorectal cancer symptoms is not related to the stage or prognosis of tumors.     

Clinical Hepatic Impairment after the Duodenal Switch

Background: Nonalcoholic steatohepatitis (NASH) is the most common histological finding in morbidly obese patients undergoing liver biopsy. Biliopancreatic diversion has been widely used for the treatment of morbid obesity and hepatic steatosis, and very few cases of liver impairment as a complication of this operation have been reported. Methods: During the last 9 years, 470 morbidly obese patients were operated by means of a biliopancreatic diversion with duodenal switch ( BPD-DS), and 93 of them were performed laparoscopically. Results: 10 cases of clinical hepatic impairment occurred after the BPD-DS. The clinical course of these patients ranged from transient subclinical alterations of liver function tests to severe cases of jaundice and one death from liver failure. Conclusion: Randomized prospective studies with standardization of BPD-DS are needed, to know the real incidence of hepatic impairment and the proper treatment for this condition. Careful follow-up and correction of possible malnutrition should be addressed to avoid hepatic impairment and/or progression of liver disease.