[Effectivity versus toxicity of minoxidil as antiproliferative agent for lens epithelial cells. In vitro study]

PURPOSE

To evaluate the inhibitory effect of minoxidil on cultured proliferating lens epithelial cells (LECs) versus cytotoxic effect over corneal endothelial cells in culture, because minimum side effects over anterior chamber structures and particularly on corneal endothelium are required for successful therapy and prevention of posterior capsular opacification (PCO).

METHODS

New Zealand Rabbit LECs and corneal endothelium were cultured in DMEM at 35 degrees C in 5% CO2 in multiwells during 7 days. Both types of cells were exposed to minoxidil (1, 2 and 4 mM) for 1 and 24 hours. Control group and balanced salt solution group were included. After seven days multiwells were processed for light microscopy study. Morphometric study of cellular population of LECs and corneal endothelium cells were done using a computed planimetry system.

RESULTS

Dose-dependent effect on LECs proliferation was noted and non-confluent colonies of cells were observed on all treated groups. Morphologic changes in normal appearance of corneal endothelial cells after 1 hour of minoxidil treatment was observed and intracellular alterations were confirmed even with the lowest dose exposure.

CONCLUSIONS

Although effectiveness of minoxidil suppressing in vitro LECs proliferation could be suggest as a useful therapeutic agent to prevent PCO, however the inhibitory effect of different concentrations on corneal endothelial cells conditioned its possible use on ocular surgery.

[Massive bilateral adrenal hemorrhage after conservative tumor surgery in the isthmus of a horseshoe kidney]

OBJECTIVE

To present a fatal case of massive bilateral suprarrenal haemorrhage (MBSH) after partial nephrectomy.

CLINICAL CASE

An 82 year old male treated with oral anticoagulants was diagnosed by means of CT scan and arteriography of having an avascular tumor located at the isthmus of a horseshoe kidney. A tumorectomy with safety surgical margins was performed; It was diagnosed of having a renal adenocarcinoma, which was almost completely necrotic. During the postoperative period, the patient presented abdominal pain, nausea, fever, hypotension and severe respiratory distress. Biochemical studies showed mild hyponatremia and azotemia, accompanied by anemia, leucocytosis and thrombocytosis. An abdominal CT scan demonstrated a MBSH, which produced the patients death soon afterwards.

DISCUSSION

Tumoral pathology of horseshoe kidneys presents important topographic and anatomopathologic differences with respect to non-fused kidneys. MBSH is a rare complication of many stress processes especially if an anticoagulant treatment coexists. The treatment has to be initiated as soon as we suspect MBSH, which should be confirmed by hormonal determinations and/or the presence of hyperdense suprarenal lesions at the CT scan.

[Clinical and functional analysis of long-term results of uvulopalatopharyngoplasty]

In order to evaluate the clinical and functional effectiveness of uvulopalatopharyngoplasty (UPPP) in chronic roncopathy, we studied the subjective improvement of operated patients and compared to pulsioximetry findings before and after surgery. A follow-up was made on 72 patients entitled of chronic roncopathy--51 with obstructive sleep apnea syndrome (OSAS) and 21 with simple snoring-, for a mean period of time of 41 months. Preoperatory study included on ENT exploration, fibre optic endoscopy, Müller maneuver, pharyngeal CT, value of daytime sleepiness with Epworth's scale, espirometry and pulsioximetry, and the postoperatory study included of pulsioximetry and a health questionnaire over snoring and daytime sleepiness. Snoring improved or disappeared in 13 of 21 patients (61.8%), and daytime sleepiness did it in 26 of 39 (66.6%). Therapeutic failure in snoring was mainly due to an increase in the body mass index. After UPPP in OSAS, only 21 patients (41.1%) showed all positive response criteria (decrease into ODI > or = 50% or in absolute values < 6, CT 90% < 1%, and SaO2 Min > or = 85%). UPPP failed in long term evaluation in the rest of individuals. Patient selection is mandatory to optimize clinical response of UPPP for snoring, without OSAS success depends on body mass index, respiratory disturbances ratios and the eventual presence of another upper airways collapses below velopharyngeal segment.

[Are we diagnosing people infected with HIV in time?]

OBJECTIVE

To describe the number of AIDS cases who did not know of their HIV infection until they developed AIDS, and the factors relating to this situation.

DESIGN

Descriptive study of data of the National AIDS Register.Setting. Spain.Patients. Cases of AIDS in the over-14s diagnosed between 1997 and 1999.

RESULTS

Of the 6910 cases of AIDS studied, 35% (n = 2421) knew that they were HIV-positive at the same time as they were diagnosed with AIDS (in the same month or the previous one). The multi-variate analysis showed that this situation occurred less commonly in women (OR = 0.61; 95% CI, 0.53-0.71), in cases diagnosed in prison (OR = 0.19; 95% CI, 0.13-0.27), in cases diagnosed early (OR = 0.49; 95% CI, 0.41-0.60) and among residents in provinces with AIDS rates higher than the Spanish average (OR = 0.88; 95% CI, 0.78-0.99). Ignorance of HIV infection until the AIDS diagnosis was associated to ages of under 25 and over 34, homo/bisexual transmission (OR = 3.20; 95% CI, 2.69-3.80) and heterosexual transmission (OR = 4.88; 95% CI, 4.21-5.65) compared with intravenous drug users, and to the person coming from countries other than Spain, both developed (OR = 2.78; 95% CI, 1.89-4.08) and under-developed (OR = 1.85; 95% CI, 1.26-2.72) countries.

CONCLUSIONS

A considerable number of people diagnosed with AIDS were unaware of their HIV infection, especially among people who had never injected drugs. HIV needs to be diagnosed earlier so as to improve prevention and treatments.

Prevalence of Neisseria meningitidis carriers in the school population of Catalonia, Spain

The aim of this study was to determine the prevalence of healthy Neisseria meningitidis pharyngeal carriers in a representative sample of the Catalonian school population, as well as its associated factors. The sample was divided into age groups: < or = 5, 6-7 and 13-14 years old. Parents were given a questionnaire to collect information on sociodemographic and epidemiological variables. Oropharyngeal swabs were collected with a cotton-tipped swab in an Amies transport medium and cultured on Thayer Martin plates at 35 degrees C in 5% CO2. The isolates were serogrouped and sero/subtyped. Of the 1406 children studied, 75 (5.34%) meningococcal carriers were detected: 63 B (4.5%), 9 non groupable (0.7%), 2 29E (0.1%) and 1X (0.07%). No serogroup C meningococci were found in this study, probably due to the high A+C vaccination coverage of up to 68.9% in children 6-7 years old. Bivariate analysis identified six statistically significant risk factors for meningococcal carriage: increasing age, recent upper respiratory tract infection, previous antibiotic treatment, number of students in the class, size of the classroom and social class. Multivariate analysis found that only age and previous antibiotic treatment remained statistically significant when the other factors were controlled.

Actin monoubiquitylation is induced in plants in response to pathogens and symbionts

Most dramatic examples of actin reorganization have been described during host-microbe interactions. Plasticity of actin is, in part, due to posttranslational modifications such as phosphorylation or ubiquitylation. Here, we show for the first time that actins found in root nodules of Phaseolus vulgaris are modified transiently during nodule development by monoubiquitylation. This finding was extended to root nodules of other legumes and to other plants infected with mycorrhiza or plant pathogens such as members of the genera Pseudomonas and Phytophthora. However, neither viral infections nor diverse stressful conditions (heat shock, wounding, or osmotic stress) induced this response. Additionally, this phenomenon was mimicked by the addition of a yeast elicitor or H2O2 to Phaseolus vulgaris suspension culture cells. This modification seems to provide increased stability of the microfilaments to proteolytic degradation and seems to be found in fractions in which the actin cytoskeleton is associated with membranes. All together, these data suggest that actin monoubiquitylation may be considered an effector mechanism of a general plant response against microbes.

Apatite nucleation on silica surface: a zeta potential approach

Zeta potential measurements on pure silica, prepared by the sol-gel method from tetraethoxysilane under acidic conditions, are reported in different suspensions. Water suspensions and suspensions containing calcium or phosphate ions with and without NaCl were tested. zeta potential measurements were carried out as a function of the pH and ion concentration. Also, calcium and phosphate adsorption on silica was determined experimentally. The results of zeta potential and adsorption measurements suggest that both calcium and phosphate ions can be adsorbed on the silica surface; however, calcium adsorption is stronger than phosphate adsorption. When calcium and sodium ions are present in the suspension, calcium adsorption decreases. It seems that certain sites on the silica surface are specific for calcium adsorption.

Characterization of GFAP expression and cell proliferation in the rat median eminence following hypophysectomy

To analyze whether the reorganization of the rat median eminence after hypophysectomy might be related to changes in glial fibrillary acidic protein (GFAP)- and cellular proliferation, the distribution of cells immunoreactive for GFAP and the proliferation rate of such cells were analyzed at 20, 40 and 60 days posthypophysectomy. For this study, four rostro-caudal regions of the median eminence were differentiated: the retrochiasmatic, preinfundibular, infundibular and postinfundibular regions. In each of these regions, three layers were studied: the ependymal, the internal and the external. At 20 and 40 days after hypophysectomy, significant increases in cellular proliferation affecting all three layers studied in the preinfundibular and infundibular regions were found. At the same time points, increases in GFAP expression were also observed. However, after 60 days, GFAP and proliferative cellular nuclear antigen (PCNA) expression decreased. Although variations of PCNA and GFAP levels were evident, no colocalisation of PCNA and GFAP was found in the cells of the median eminence in untreated or hypophysectomized rats when sections were analyzed by double immunohistochemical staining. Our results suggest that reorganization of median eminence involves alterations (or modulation) of GFAP-immunoreactive cells together with a proliferation of cells that are not GFAP-immunoreactive. This study also demonstrates that this reorganization is completed within the first two months after hypophysectomy.

[A viral infection in the neck glandula of larvae of Dione junio (Lepidoptera: Nymphalidae)]

Lepidopteran larvae may be attacked by different viruses, many of which belong to the Baculoviridae family. Whilst studying the ultrastructure of the neck gland in Dione junio larvae we found that in later instars the larvae showed symptoms of attack by two types of virus. The glands were prepared for optical and electron microscopy using sodium cacodylate buffer and standard procedures (0.1M, pH 7.2). The neck gland is composed of two oval internal sacks which communicate with the exterior via an extracellular channel. Each sack contains, in its external region, cells with large, irregular nuclei and a dense cytoplasm containing numerous small mitochondria. In infected larvae, the tissues are damaged and the nuclear polyhedrosis virus can be observed in several of the nuclei. In the cytoplasm another "rickettsia type" virus, may be observed. The pathogenic viruses present in D. junio larvae could be studied as potential biological controls of this pest.

Mediterranean and low-fat diets improve endothelial function in hypercholesterolemic men

BACKGROUND

The regulatory function of the endothelium is altered in hypercholesterolemia, and the subsequent endothelial dysfunction plays a central role in the development of atherosclerosis.

OBJECTIVE

To determine whether endothelial function in hypercholesterolemic patients is affected by replacing a saturated fat-enriched diet with a low-fat, low-saturated fat diet (the U.S. National Cholesterol Education Program stage 1 [NCEP-1] diet) or a diet rich in monounsaturated fat (such as that common in Mediterranean countries).

DESIGN

Intervention dietary study with a baseline phase and two randomized crossover dietary periods.

SETTING

Hospital Universitario Reina Sofía, Córdoba, Spain.

PATIENTS

22 hypercholesterolemic men.

INTERVENTION

Patients followed a diet high in saturated fat, then were assigned in a crossover design to the NCEP-1 diet or a Mediterranean diet. Each dietary period lasted 28 days.

MEASUREMENTS

Plasma P-selectin levels, lipid concentrations, and endothelial function.

RESULTS

Compared with the saturated fat diet, flow-mediated dilatation increased during the Mediterranean diet but not during the NCEP-1 diet. In addition, levels of plasma cholesterol, low-density lipoprotein cholesterol, apolipoprotein B, and P-selectin decreased during the NCEP-1 and Mediterranean diets.

CONCLUSION

In hypercholesterolemic men, diets low in fat (especially saturated fat) and diets rich in monounsaturated fats improve endothelial function.

Quantitative hepatitis B virus DNA testing for the early prediction of the maintenance of response during lamivudine therapy in patients with chronic hepatitis B

To determine whether a dramatic decrease in hepatitis B virus (HBV) DNA levels within the first months of lamivudine therapy can predict the emergence of YMDD variants in patients with chronic hepatitis B, quantitative testing was done every 3 months on serum samples from 35 patients who were treated with lamivudine for >1 year. The decline in HBV DNA levels from baseline to month 3 was higher in 22 responders than in 13 nonresponders (mean+/-SD, 4.16+/-1.06 vs. 2.88+/-1.77 log(10) copies; P=.002), whereas no differences were observed in patients with and without YMDD variants at 1 year of therapy. At 3 months, HBV DNA was undetectable in 77% of the responders, whereas, after 1 year, it was undetectable in 23% of nonresponders, 40% of patients with YMDD variants, and 74% of those without variants. Therefore, quantitative HBV DNA testing is very useful in deciding whether to continue therapy, because of the low likelihood of response in patients who remain HBV DNA positive at month 3 of treatment.

Estradiol influences the LH response to met-enkephalin. An immunocytochemical and morphometric study

In order to test the possible role of estradiol in the response of the LH-adenohypophyseal cells to the administration of met-enkephalin in the albino male rat, an immunocytochemical (peroxidase-antiperoxidase), morphometric (cellular and nuclear areas and numerical density) and radioimmunoassay (LH serum levels at the moment of sacrifice) study was carried out. The intraventricular administration of met-enkephalin (150 micrograms in 25 microliters of distilled water) does not produce any changes in the parameters considered. However, when the animals were pretreated with estradiol (chronically, 15 days), met-enkephalin produced a significant decrease in all the parameters considered.

[Early diagnosis of retinoblastoma: usefulness of searching for RB1 gene mutations]

BACKGROUND

Retinoblastoma, the intraocular malignancy most common in children,occurs in both familial and sporadic (bilateral or unilateral). Hereditary predisposition is caused by a germ-line mutation while non-hereditary is due to two somatic mutations in a retinal cell. This work was carried out in order to analyse genetically, the high number of families with some affected member and to go deep into the molecular mechanisms responsible of this pathology.

PATIENTS AND METHOD

59 families with one or more affected members were analysed. Cytogenetics and with polymorphic markers studies were carried out and a search for mutations was performed in DNA from white cells and from available tumoral tissue.

RESULTS

In four of the 5 familial cases, the responsible mutation was established,the same as in 9 of the 13 bilateral sporadic. In the 7% of the unilateral sporadic cases, mutation was found in leucocytary DNA. Lost of heterozygosity as a second mutational event was mainly due to mitotic recombination.

CONCLUSIONS

Among the mutations of our series, a higher frequency of punctual mutations,responsible of the first mutational event, was observed at constitutional level. Lost of heterozygosity was the mechanism observed in the majority of the tumours.

Different strategies to recover the activity of monomeric triosephosphate isomerase by directed evolution

A monomeric version of triosephosphate isomerase from Trypanosoma brucei, MonoTIM, has very low activity, and the same is true for all of the additional monomeric variants so far constructed. Here, we subjected MonoTIM to directed evolution schemes to achieve an activity improvement. The construction of a suitable strain for genetic selection provided an effective way to obtain active catalysts from a diverse population of protein variants. We used this tool to identify active mutants from two different strategies of mutagenesis: random mutagenesis of the whole gene and randomization of loop 2. Both strategies converged in the isolation of mutations Ala43 to Pro and Thr44 to either Ala or Ser, when randomizing the entire gene or to Arg in the case of randomization of loop 2. The kinetic characterization of the two more active mutants showed an increase of 11-fold in k(cat) and a reduction of 4-fold in K(m) for both of them, demonstrating the sensitivity of the selection method. A small difference in growth rate is observed when both mutant genes are compared, which seems to be attributable to a difference in solubility of the expressed proteins.