The nucellus degenerates by a process of programmed cell death during the early stages of wheat grain development

The nucellus, which is the maternal tissue of the wheat grain, degenerates during the early stages of development. We have investigated whether or not this degenerative process may be considered as programmed cell death (PCD). The analysis of DNA of tissues dissected from developing wheat (Triticum aestivum L. cv Chinese Spring) grains at 5-20 days post anthesis (dpa) showed the presence of DNA laddering, which is indicative of internucleosomal fragmentation of nuclear DNA, in maternal tissues but not in the endosperm. The TUNEL assay showed in-situ internucleosomal fragmentation of DNA in nuclei of parenchymal and epidermal cells of the nucellus, as well as in the pericarp, during the early stages of grain development (5 dpa). Furthermore, internucleosomal fragmentation of nuclear DNA was observed in nucellar projection cells in the middle stages of grain development (13-18 dpa), thus showing a process of PCD in these maternal tissues. Electron-transmission microscopy analysis allowed the morphology of PCD to be characterized in this plant tissue. Initially, fragmentation of the cytoplasm was observed, the nuclear envelope appeared dilated and to be forming vacuoles, and the content of heterochromatin increased. A progressive degradation of the cytosolic contents and organelles was observed, and the plasma membrane was disrupted. However, the Golgi apparatus remained intact and apparently functional even in the final stages of cell death.

Influence of nutritional and environmental factors on polysaccharide production by Azotobacter vinelandii cultured on 4-hydroxybenzoic acid

The capacity of 4-hydroxybenzoic acid to support exopolysaccharide (EPS) biosynthesis was investigated. Carbon source concentration, nitrogen supplementation, and other nutritional and environmental factors were optimized to obtain maximal EPS recovery. Higher EPS yields were obtained in nitrogen-free media amended with 20-30 mM 4-hydroxybenzoic acid. In general, modifications in inorganic salt concentration did not alter EPS production, except in the case of magnesium ions. Increased levels of this cation were correlated to greater EPS yields. Production was strongly influenced by certain environmental factors. Optimal values of 34 degrees C, 80 rpm and neutral or slightly basic conditions were selected. Under these conditions, more than 25% of the carbon source supplied was converted to EPS and the production was improved about 42% in comparison to that observed in the initial media.

Xanthomonas campestris strain selection for xanthan production from olive mill wastewaters

Four Xanthomonas campestris strains were tested in olive mill wastewaters (OMW) for xanthan production. Differences among strains were found in the range of tolerance to OMW concentration and xanthan amount obtained. X. campestris NRRL B-1459 S4LII was chosen by its capability for xanthan production from 50-60% OMW as the sole nutrient source.

[Testicular dislocation. Report of 2 new cases and review of the literature]

We report 2 new cases of testicular luxation. A review of current literature is made. Testis was located inguinal after scrotal trauma in both cases. Early close reduction was unsuccessfully. A delayed reduction was found in one case at the moment of surgery. A surgical replacement of the testis was carried out in the other patient. Follow-up control revealed a benign course in both. Testicular dislocation is a rare complication after scrotal trauma (only 152 cases reported). Physician have to be aware of this possibility following perineal trauma. Oftenly, a surgery reduction is required.

Extrathyroid spread in papillary carcinoma of the thyroid: clinicopathological and prognostic study

INTRODUCTION

The extrathyroid spread (ETS) is one of the risk factors that influence mortality and recurrence in patients with papillary carcinoma of the thyroid (PCT). The aim of this study is to analyze the clinical and histologic features and follow-up of a series of patients with ETS undergoing surgery for PCT and to identify patients with a greater risk of presenting with ETS.

MATERIAL AND METHODS

Retrospective study of a series of 200 patients undergoing surgery for PCT, of whom 47 (23.5%) presented with ETS. The clinical and histologic features and follow-up of the patients with ETS were compared with those without ETS using the Pearson chi(2) test. We used a logistics regression model to perform a multivariant analysis for ETS. The survival and disease-free interval rates were calculated using the Kaplan-Meier method.

RESULTS

ETS is most associated with patients over 50 years of age, with tumors over 4 cm that are not encapsulated, with lymph node metastasis, and with certain PCT histologic subtypes after the multivariant analysis. The overall rate of recurrence and mortality in patients with ETS was much higher than in patients without ETS.

CONCLUSIONS

PCT patients with ETS have a greater risk of tumor-related recurrence and mortality than patients without ETS. There are patients with certain clinical and histologic features who have a greater risk of presenting with ETS.

Prevalence of coeliac disease in Down's syndrome

OBJECTIVE

During the past decade, it has been shown that the association between Down's syndrome and coeliac disease is relatively frequent Prevalence rates of coeliac disease in patients with Down's syndrome reported by different authors are significantly higher than those found in the general population. The main purpose of this study was to assess the prevalence of coeliac disease in a series of subjects with Down's syndrome from our geographical area.

DESIGN

A cross-sectional study.

SETTING

Outpatient paediatric clinics of acute-care teaching hospitals in Barcelona, Spain.

PARTICIPANTS

A total of 284 persons with Down's syndrome aged between 1 and 25 years were included in the study. In all cases, serum concentrations of antigliadin antibodies (AGAs) (Pharmacia CAP system enzyme-linked immunosorbent assay), antiendomysium antibodies (AEA) (indirect immunofluorescence) of immunoglobulin (Ig)A class or IgG class in cases of IgA deficiency were determined. Jejunal biopsy was offered to all patients with AEA positivity and to those with suggestive clinical manifestations of coeliac disease. In all patients, a clinical study was made to evaluate the presence and time-course of symptoms related to coeliac disease.

MAIN OUTCOME MEASURES AND RESULTS

In 18 of the 284 subjects with Down's syndrome, aged between 2 and 15 years, coeliac disease was confirmed by jejunal biopsy. Accordingly, the minimum prevalence rate of coeliac disease was of 6.3%. Ninety-four percent (17/18) and 78% (14/18) of patients with the association Down's syndrome and coeliac disease showed AEA and AGA positivity, respectively. Fifteen patients with the association coeliac disease and Down's syndrome (15/18) showed clinical manifestations compatible with coeliac disease, with a predominance of intestinal symptoms (8/18) over those with atypical or extra-intestinal forms (7/18). Three patients had clinically silent forms of coeliac disease (3/ 18).

CONCLUSIONS

Measurement of serum concentrations of AEA should be added to the list of screening tests for coeliac disease in patients with Down's syndrome, otherwise definite association between both diseases may pass unnoticed and diagnosis of coeliac disease be considerably delayed.

Lutein production by Muriellopsis sp. in an outdoor tubular photobioreactor

The effect of dilution rate, mixing and daily solar cycles on lutein and biomass productivity of the green unicellular alga Muriellopsis sp. has been studied, throughout the year, in an outdoor tubular photobioreactor. Highest productivity values, for both lutein (about 180 mg m(-2) per day) and biomass (about 40 g (dry weight) m(-2) per day) were achieved on May and July. Values for the optimal dilution rate varied, being lower in May (0.06 h(-1)) than in November (0.09 h(-1)). Similar values for photosynthetic efficiency (about 4%) were recorded throughout the year, indicating that optimization of culture conditions was achieved for each experimental period. Along the daily solar cycle, there was a fast increase of lutein content of Muriellopsis sp. in response to irradiance during the early hours of daytime, with maximal lutein content (about 6 mg (g dry weight)(-1)) being recorded at noon, and decreasing slowly, thereafter. An increase in cell growth was observed following the establishment of maximum lutein/chlorophyll ratio, which might indicate a role for lutein in protecting cells from photodamage.

Differential regulation of the expression of CD95 ligand, receptor activator of nuclear factor-kappa B ligand (RANKL), TNF-related apoptosis-inducing ligand (TRAIL), and TNF-alpha during T cell activation

Members of TNF superfamily are characterized by their ability to inflict apoptosis upon binding to their cognate receptors in a homotrimeric manner. These proteins are expressed on different cell types under various conditions. However, the mechanisms governing the expression of these molecules remain elusive. We have found that the TCR signal can elicit the expression of receptor activator of NF-kappaB ligand (RANKL), TNF-alpha, CD95L, and TNF-related apoptosis inducing ligand (TRAIL) in T cell hybridoma A1.1 cells, thus allowing us to examine the expression pattern of these molecules under precisely the same conditions. We have previously reported that CD95L expression requires both protein kinase C (PKC) translocation and Ca2+ mobilization and is inhibited by cyclosporin A, and dexamethasone. We demonstrate now that activation-induced expression of RANKL is mediated by Ca2+ mobilization. PKC activation does not induce RANKL expression nor does it synergize with the Ca2+ signal. Activation-induced RANKL expression is blocked by cyclosporin A, but not by dexamethasone. The expression of TNF, in contrast, is mediated by PKC, but not by Ca2+. TNF-alpha expression is not inhibited by cyclosporin A, but is sensitive to dexamethasone. A1.1 cells constitutively express TRAIL at low levels. Stimulation with anti-CD3 leads to an initial reduction and subsequent increase in TRAIL expression. TRAIL induction is not inhibited by cyclosporin A, but highly sensitive to dexamethasone. Therefore, expression of the TNF superfamily genes is regulated by distinct signals. Detailed understanding of the regulatory mechanisms could provide crucial information concerning the role of these molecules in the modulation of the immune system.

[Chlamydia pneumoniae and cerebrovascular disease]

INTRODUCTION

Chlamydia pneumoniae has relationship with artherosclerosis of carotid artery by seroepidemiological studies and by demonstration of the bacteria in atheromata. We made a case-control study to know the seroprevalence of chronic infection of C. pneumoniae and the presence of the bacteria in arterial biopsies.

PATIENTS AND METHODS

The cases group was constituted by 26 patients undergoing carotid surgery. In the control group there were 50 patients without atherosclerosis and who underwent removal of their varicose veins. There were matched for sex, age and smoking. We obtained serum samples to determinate IgG antibodies against MOMP by MIF and ELISA. In the cases group, we got the arterial biopsies from carotid artery, and from pudendal arteries in control group. We determined chlamydial DNA on the biopsies by heminested PCR (primers: HL-1, HM-1, HR-1). We measured fibrinogen in both groups.

RESULTS

By MIF technique, the seroprevalence was (IgG > 1:32) 69.23% cases versus 24% controls (OR: 7.12, CI: 2.47-20.48). The ELISA showed 76.92% of seropositivity in cases versus 16% in controls (OR: 17.5, CI: 95%: 5.35-57.23). The DNA of C. pneumoniae was found in 18 cases and 6 controls, (p < 0.0001, chi 2). We did not find any relationship between fibrinogen levels and groups.

CONCLUSION

We think that there is a relationship between chronic infection with C. pneumoniae and carotid atherosclerosis.

Electroanalytical determination of cadmium and lead in deciduous teeth after microwave oven digestion

A method using differential pulse anodic stripping voltammetry after microwave oven digestion was developed for the simultaneous determination of Cd(II) and Pb(II) in the deciduous teeth of children. Each tooth was weighed; deposited in a 120 mL capped Teflon vessel with 5 mL 65% nitric acid, Suprapur analytical grade; and digested in a 2-step microwave oven for 15 min. The detection limits for Cd(II) and Pb(II) in the final solution were 0.078 and 0.323 microg/L, and the quantitation limits 0.394 and 1.613 microg/L, respectively, with a linearity range of 2 microg/L for Cd(II) and 23.3 microg/L for Pb(II). The sensitivity was 2.51 nA/microg-L and 1.37 nA/microg-L, for Cd(II) and Pb(II). The main advantages of this technique are a complete and satisfactory dissolution of the tooth material with the proposed microwave oven digestion procedure, without sample pretreatments, such as drying, ashing, or powdering. The voltammetric procedure proved to be well designed because of significant goodness of fit to a linear model, and the accuracy of the method was established as compared with standard reference material. The methodology has enabled us to study Cd(II) and Pb(II) in 371 deciduous teeth from school children in Cartagena, Spain.

Strategies to enhance the biodegradation of toxic compounds using discontinuous processes

This study presents two strategies used to enhance the biological degradation of phenolic wastewaters. In the first one the operation of a sequencing batch biofilter added with granular activated carbon (SBB-AC) was studied. The second strategy presents the results of the automation of a sequencing batch reactor in order to optimize the reaction phase. In this case, the dissolved oxygen was employed to monitor and control the reactor. The results of the SBB-AC system, based on the configuration of the reactor, type and size of activated carbon and size of the packing material, are discussed. The system biodegraded efficiently (total phenol removals as high as 97%) high concentrations (600 mg/l) of a mixture of phenol, 4-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol. Maximal eliminated loads of 4.33 kg COD/m3-d were achieved. For the second strategy, the applicability of an optimal control for a SBR using the dissolved oxygen as the measured variable was demonstrated. When the reactor was operated under the time-optimal control strategy, the degradation time of 4-chlorophenol was reduced. A very satisfactory operation of the reactor was observed, since the removal efficiencies were around 99%.

Are avian blood parasites pathogenic in the wild? A medication experiment in blue tits (Parus caeruleus)

The Hamilton and Zuk hypothesis on haemoparasite-mediated sexual selection and certain studies of reproductive costs are based on the assumption that avian blood parasite infections are detrimental to their hosts. However, there is no experimental evidence demonstrating harmful effects of blood parasites on fitness in wild populations, it even having been suggested that they may be non-pathogenic. Only an experimental manipulation of natural blood parasite loads may reveal their harmful effects. In this field experiment we reduced through medication the intensity of infection by Haemoproteus majoris and the prevalence of infection by Leucocytoazoon majoris in blue tits (Parus caeruleus), and demonstrated detrimental effects of natural levels of infection by these common parasite species on host reproductive success and condition. The fact that some of the costs of infection were paid by offspring indicates that blood parasites reduce parental working capacity while feeding nestlings. Medicated females may be able to devote more resources to parental care through being released from the drain imposed upon them by parasites and/or through a reduced allocation to an immune response. Therefore, this work adds support to previous findings relating hosts' life-history traits and haematozoan infections.

Usefulness of unipolar electrograms to detect isthmus block after radiofrequency ablation of typical atrial flutter

BACKGROUND

RS morphology of the unipolar electrogram is associated with propagation of the wave front through the exploring electrode, whereas positive uniphasic (R) unipolar electrograms are characteristic of the end of activation.

METHODS AND RESULTS

Unipolar electrograms were recorded in 45 consecutive patients with atrial flutter who were undergoing radiofrequency ablation (RFA). Bidirectional cavotricuspid isthmus (CTI) block was achieved in 44 patients. The unipolar electrogram obtained before RFA at the low anterolateral right atrium during coronary sinus pacing changed from RS, rS, or QS to R or Rs in all patients after clockwise CTI block was obtained. The morphology of unipolar electrograms recorded close to the coronary sinus during pacing from the low anterolateral right atrium changed from RS or rS to R or Rs in all but 4 patients after counterclockwise CTI block. In the patient in whom CTI block was not achieved, the RS morphology of the unipolar electrogram remained unchanged. In 18 patients, the results of the RFA were assessed with only the unipolar electrogram. The unipolar electrogram correctly predicted 100% and 89% of the cases of clockwise and counterclockwise CTI block, respectively.

CONCLUSIONS

The creation of CTI block is associated with an easily detectable loss of negative components and development of an R or Rs pattern of the unipolar electrogram recorded close to the ablation line while pacing at the opposite side of the CTI.

Canine leishmaniasis transmission: higher infectivity amongst naturally infected dogs to sand flies is associated with lower proportions of T helper cells

The dog is the main reservoir of Leishmania infantum, which is a parasite spread among canine hosts by the bite of sand flies. Phlebotomus perniciosus is the sand fly acting as a major vector in the Mediterranean basin. As a consequence, the dog will suffer from leishmaniasis. In this work the infective capacity of infected dogs, established by direct xenodiagnosis, has been investigated in relation to their immunological status by determining the lymphocyte percentages present in peripheral blood mononuclear cells. We found a significant association between the percentages of T helper cells (CD4/TcR alpha beta(+)and CD4/CD45RA(+)) and the infection rates detected in the vector, while significant association was not detected in the case of the T cytotoxic cells (CD8/TcR alpha beta(+)and CD8/CD45RA(+)). The relationship discovered was that the lower the CD4(+)T cell count, the higher the rate of the infection in the vector.

Polymorphisms of octopine dehydrogenase (Odh) in mollusks and implications for the neutralism-selectionism hypothesis

Octopine dehydrogenase (Odh) was examined in several species of bivalves and gastropods and complemented with bibliographic data, to assess the controversy between neutralism and selectionism in explaining the maintenance of genetic variation in natural populations. This debate was the center of the molecular evolution and population genetic research in the 1970s and 1980s, but waned thereafter, without resolution. Although DNA data have been produced, implications are not understood. We examined the polymorphims of Odh in several species of bivalves and gastropods, and the kinetic properties (apparent Km) of the different isozymes in the scallop Euvola ziczac that indicates an apparent case of overdominance of the heterozygous individuals. The question "which of the two hypothesis is correct" has shifted with time to "how much influence did each factor have in the maintenance of genetic variation".

[Pneuropsychological disorders after occupational exposure to mercury vapors in El Bagre (Antioquia, Colombia)]

INTRODUCTION

The department of Antioquia in Columbia is the main producer of gold in Columbia. In the gold-producing regions the population is exposed to high levels of mercury used in the processes of extraction and purification. Studies done in Columbia on neurotoxicity underline the hazards of mercury from the environmental and occupational-health point of view, but the effect of long-term exposure on cognitive function has not been studied.

OBJECTIVE

To determine whether the miners of El Bagre (Antioquia, Columbia) have neuropsychological and/or behavior disorders as a result of occupational exposure to toxic mercury vapor.

PATIENTS AND METHODS

The sample was made up of 22 right-handed men, residents of El Bagre, aged between 20 and 45 years old who had been exposed to mercury vapor for at least three years. The control group consisted of 22 men who lived in the non-mining regions of the department and had not been exposed to mercury, paired with the cases considered for age and educational status. Neuropsychological assessment, a medical examination and behavioral performance tests were applied to all the men (in both groups).

RESULTS

In the study group alterations were seen and classified as: intellectual damage (mainly alteration of executive function and constructional praxis); emotional changes (symptoms of depression and anxiety) and neurological changes (amnesia, insomnia and tremor of the tongue). No changes were found in the control group.

CONCLUSION

Exposure to mercury causes specific neuropsychological and behavior disorders in the absence of clinically detectable physical or physiological damage.

Image processing from computerized tomography images: virtual reconstruction for telediagnosis

We have developed a system for remote three-dimensional reconstruction, which facilitates telediagnosis. The telereconstruction system is based on a computerized tomography (CT) scanner, a workstation connected to the CT scanner, a PC, which can be geographically far away from the workstation, and a computer program that we have developed. The workstation allows CT images to be stored and image processing to be carried out. The PC permits the user to control the workstation in making a three-dimensional reconstruction and allows the remote user to see that reconstruction. From the PC various graphical operations can be performed on the three-dimensional model, such as rotations, translations and cuts through the model. The program therefore allows a remote user to have three-dimensional images and to study them by means of all the options the program provides.

Telereconstruction from computerized tomography images for the distance teaching of medicine

A system for making remote two- and three-dimensional reconstructions from computerized tomography images has been developed in order to improve medical teleteaching. It allows the automatic two- and three-dimensional remote visualization of the anatomical structure of interest. As a part of this system, software has been developed which allows many visual operations or transformations on a remote three-dimensional model. It permits the remote workstation and the local workstation to visualize every transformation simultaneously. It allows a doctor to interact virtually and remotely with the anatomical structure. The software enables examination of the anatomical model from all angles, even from inside (including planar and three-dimensional presentations).

[Loss of heterozygosity in the 9p21 region as an inactivation mechanism of the p16 suppressor gene]

OBJECTIVE

To determine the loss of heterozygosity (LOH) on 9p21 (locus D9S1747) in patients with renal carcinoma by analysis of microsatellite polymorphisms.

METHODS

40 patients with sporadic renal cancer were studied. LOH on 9p21 was performed by analysis of microsatellite polymorphisms.

RESULTS

23.7% showed LOH on 9p21. No correlation was found between this genetic alteration and tumor features.

CONCLUSIONS

LOH on 9p21 was found in 23.7% of the patients in this series. LOH was found in 26.9% of renal cell carcinomas, 25% of papillary carcinomas and 25% of Bellini duct carcinomas. LOH was not found in the other histological types.