Profiling wastewater characteristics in intra-urban catchments using online monitoring stations

This study aims to investigate the differences in intra-urban catchments with different characteristics through real-time wastewater monitoring. Monitoring stations were installed in three neighbourhoods of Barcelona to measure flow, total chemical oxygen demand (COD), pH, conductivity, temperature, and bisulfide (HS-) for 1 year. Typical wastewater profiles were obtained for weekdays, weekends, and holidays in the summer and winter seasons. The results reveal differences in waking up times and evening routines, commuting behaviour during weekends and holidays, and water consumption. The pollutant profiles contribute to a better understanding of pollution generation in households and catchment activities. Flows and COD correlate well at all stations, but there are differences in conductivity and HS- at the station level. The article concludes by discussing the operational experience of the monitoring stations.

Seamless integration of sewer system topology and tree location data: An algorithm to diagnose the potential impact of tree roots on pipes and propose rearrangement solutions

Wastewater networks are subject to several threats leading to wastewater leakages and public health hazards. External elements such as natural factors and human activities are common causes of wastewater leakages and require more in-depth analysis. Prevention and rehabilitation work is essential to secure wastewater networks and avoid pipe failures. This work presents a new algorithm that allows for the seamless integration of sewer topology and tree location data to diagnose the potential impact of tree roots on pipes. The algorithm also proposes tree rearrangement options that balance the cost of tree rearrangement with the cost of pipe repair. The paper also showcases a real-world case study in the city of Girona to evaluate the performance of the presented algorithms for a specific case focusing on tree roots as a natural factor. Results show that it is possible to optimally rearrange a number of the trees with the greatest impact, significantly minimizing pipe failures and wastewater leakages (82% risk reduction with only rearranging a 12% of the most impactful trees). The rearrangement solution not only protects the environment and prevents public health hazards, but also achieves a positive economic payback during the operational period of the pipes, saving up to 1.33M€ for a tree rearrangement of 7%. The presented methodology is applicable to other natural or human factors.

Optimal design of water reuse networks in cities through decision support tool development and testing

Water scarcity and droughts are an increasing issue in many parts of the world. In the context of urban water systems, the transition to circularity may imply wastewater treatment and reuse. Planning and assessment of water reuse projects require decision-makers evaluating the cost and benefits of alternative scenarios. Manual or semi-automatic approaches are still common practice for planning both drinking and reclaimed water distribution networks. This work illustrates a decision support tool that, based on open data sources and graph theory coupled to greedy optimization algorithms, is able to automatically compute the optimal reclaimed water network for a given scenario. The tool provides not only the maximum amount of served reclaimed water per unit of invested cost, but also the length and diameters of the pipes required, the location and size of storage tanks, the population served, and the construction costs, i.e., everything under the same architecture. The usefulness of the tool is illustrated in two different but complementary cities in terms of size, density, and topography. The construction cost of the optimal water reclaimed network for a city of approximately 100,000 inhabitants is estimated to be in the range of €0.17-0.22/m³ (for a payback period of 30 years).

Optimal selection of monitoring sites in cities for SARS-CoV-2 surveillance in sewage networks

Selecting sampling points to monitor traces of SARS-CoV-2 in sewage at the intra-urban scale is no trivial task given the complexity of the networks and the multiple technical, economic and socio-environmental constraints involved. This paper proposes two algorithms for the automatic selection of sampling locations in sewage networks. The first algorithm, is for the optimal selection of a predefined number of sampling locations ensuring maximum coverage of inhabitants and minimum overlapping amongst selected sites (static approach). The second is for establishing a strategy of iterations of sample&analysis to identify patient zero and hot spots of COVID-19 infected inhabitants in cities (dynamic approach). The algorithms are based on graph-theory and are coupled to a greedy optimization algorithm. The usefulness of the algorithms is illustrated in the case study of Girona (NE Iberian Peninsula, 148,504 inhabitants). The results show that the algorithms are able to automatically propose locations for a given number of stations. In the case of Girona, always covering more than 60% of the manholes and with less than 3% of them overlapping amongst stations. Deploying 5, 6 or 7 stations results in more than 80% coverage in manholes and more than 85% of the inhabitants. For the dynamic sensor placement, we demonstrate that assigning infection probabilities to each manhole as a function of the number of inhabitants connected reduces the number of iterations required to detect the zero patient and the hot spot areas.

Tuberculous sacroiliitis in a patient with systemic lupus erythematosus: a case report and literature review

Systemic lupus erythematosus (SLE) patients are at higher risk of developing opportunistic infections such as tuberculosis (TB), especially extrapulmonary forms like osteoarticular TB, compared to the general population. However, tuberculous sacroiliitis has been scarcely reported in these patients. We present a 34-year-old woman with SLE who developed articular tuberculosis simultaneously affecting the right sacroiliac joint and the left knee. The patient was successfully treated with antituberculosis therapy for nine months. In this case, in addition to the immunological abnormalities of lupus, the long-term glucocorticoid therapy at high dosages was the main risk factor for the development of osteoarticular tuberculosis.

Robustness surfaces of complex networks

Despite the robustness of complex networks has been extensively studied in the last decade, there still lacks a unifying framework able to embrace all the proposed metrics. In the literature there are two open issues related to this gap: (a) how to dimension several metrics to allow their summation and (b) how to weight each of the metrics. In this work we propose a solution for the two aforementioned problems by defining the R*-value and introducing the concept of robustness surface (Ω). The rationale of our proposal is to make use of Principal Component Analysis (PCA). We firstly adjust to 1 the initial robustness of a network. Secondly, we find the most informative robustness metric under a specific failure scenario. Then, we repeat the process for several percentage of failures and different realizations of the failure process. Lastly, we join these values to form the robustness surface, which allows the visual assessment of network robustness variability. Results show that a network presents different robustness surfaces (i.e., dissimilar shapes) depending on the failure scenario and the set of metrics. In addition, the robustness surface allows the robustness of different networks to be compared.

In early development of the rat mRNA for the major myelin protein P(0) is expressed in nonsensory areas of the embryonic inner ear, notochord, enteric nervous system, and olfactory ensheathing cells

The myelin protein P(0) has a major structural role in Schwann cell myelin, and the expression of P(0) protein and mRNA in the Schwann cell lineage has been extensively documented. We show here, using in situ hybridization, that the P(0) gene is also activated in a number of other tissues during embryonic development. P(0) mRNA is first detectable in 10-day-old embryos (E10) and is at this time seen only in cells in the cephalic neural crest and in the otic placode/pit. P(0) expression continues in the otic vesicle and at E12 P(0) expression in this structure largely overlaps with expression of another myelin gene, proteolipid protein. In the developing ear at E14, P(0) expression is complementary to expression of serrate and c-ret mRNAs, which later are expressed in sensory areas of the inner ear, while expression of bone morphogenetic protein (BMP)-4 and P(0), though largely complementary, shows small areas of overlap. P(0) mRNA and protein are detectable in the notochord from E10 to at least E13. In addition to P(0) expression in a subpopulation of trunk crest cells at E11/E12 and in Schwann cell precursors thereafter, P(0) mRNA is also present transiently in a subpopulation of cells migrating in the enteric neural crest pathway, but is down-regulated in these cells at E14 and thereafter. P(0) is also detected in the placode-derived olfactory ensheathing cells from E13 and is maintained in the adult. No signal is seen in cells in the melanocyte migration pathway or in TUJ1 positive neuronal cells in tissue sections. The activation of the P(0) gene in specific tissues outside the nervous system was unexpected. It remains to be determined whether this is functionally significant, or whether it is an evolutionary relic, perhaps reflecting ancestral use of P(0) as an adhesion molecule.

Amino acid nitrosation products as alkylating agents

Nitrosation reactions of alpha-, beta-, and gamma-amino acids whose reaction products can act as alkylating agents of DNA were investigated. To approach in vivo conditions for the two-step mechanism (nitrosation and alkylation), nitrosation reactions were carried out in aqueous acid conditions (mimicking the conditions of the stomach lumen) while the alkylating potential of the nitrosation products was investigated at neutral pH, as in the stomach lining cells into which such products can diffuse. These conclusions were drawn: (i) The alkylating species resulting from the nitrosation of amino acids with an -NH(2) group are the corresponding lactones; (ii) the sequence of alkylating power is: alpha-lactones > beta-lactones > gamma-lactones, coming respectively from the nitrosation of alpha-, beta-, and gamma-amino acids; and (iii) the results obtained may be useful in predicting the mutagenic effectiveness of the nitrosation products of amino acids.

Formation of intranuclear crystalloids and proliferation of the smooth endoplasmic reticulum in schwann cells induced by tellurium treatment: association with overexpression of HMG CoA reductase and HMG CoA synthase mRNA

Administration of tellurium (Te) in weaning rats causes a well-established demyelinating neuropathy induced by the inhibition in myelinating Schwann cells (SC) of the synthesis of cholesterol, a major component of the myelin sheath, at the level of squalene epoxidase. We have used this experimental model of Te neuropathy to study the biogenesis and reorganization of the endomembranes of the nuclear envelope and endoplasmic reticulum (ER) in response to Te treatment by ultrastructural analysis and in situ hybridization for the detection of HMG CoA reductase and synthase mRNA, which encode key enzymes in cholesterol synthesis. The adaptive response of myelinating SC to cholesterol depletion includes cell hypertrophy, the formation of tubular invaginations of proliferating nuclear membranes giving rise to peculiar nuclear inclusions termed crystalloids, and, at the cytoplasmic level, the formation of lamellar bodies of rough ER, proliferation of the smooth ER, and overexpression of HMG CoA reductase and synthase mRNAs. The changes revert after withdrawal of Te treatment. Our results show that the biogenesis and structural organization of both endomembrane systems change dynamically upon Te-induced cholesterol depletion, indicating that this constituent plays a critical role in the organization of nuclear envelope and ER compartments in SC. The results also suggest that the HMG CoA reductase, an integral membrane protein of ER, provides the signal for the extensive membrane assembly. While the physiological meaning of crystalloid remains to be clarified, the hypertrophy of the smooth ER may represent a cytoprotective mechanism involved in detoxification of the neurotoxic agent or its metabolic derivates.

Necrosis of schwann cells during tellurium-induced primary demyelination: DNA fragmentation, reorganization of splicing machinery, and formation of intranuclear rods of actin

We present a cytological, immunocytochemical, and biochemical study of the cell death of mature myelinating Schwann cells (SCs) in the primary demyelinating neuropathy induced by tellurium (Te). Weaned rats were fed a diet containing 1.1% elemental Te. The animals were killed daily within the first week of Te diet. After 4 to 6 days of Te treatment some SCs underwent degeneration and necrosis. By electron microscopy analysis, degenerating SCs showed chromatin condensation, detachment from the nuclear envelope of condensed chromatin clumps, aggregation of interchromatin granule clusters, formation of intranuclear bundles of microfilaments, and cytoplasmic vesiculation. By confocal laser fluorescence microscopy, chromatin regions were stained with the TUNEL method for in situ labeling of DNA fragmentation and exhibited a progressive reduction of histone signal. In addition, splicing small nuclear ribonucleoprotein (snRNP) factors were redistributed in a few large nuclear domains and bright foci of intranuclear actin were observed. DNA electrophoresis revealed a smear pattern of DNA fragmentation in sciatic nerve samples from Te-treated animals. Upon Te treatment, no degradation of the caspase substrates poly (ADP-ribose) polymerase and lamin B was detected by Western blots or immunocytochemistry, respectively. The peculiar structural rearrangement of the transcription and splicing machinery as well as the vesicular degeneration of the cytoplasm in degenerating SCs support an autophagic cell death of the necrotic type. Unlike the apoptosis of pre-remyelinating SCs (11), this caspase independent cell death of necrotic type involves mature pre-demyelinating SCs and eliminates SCs injured by the neurotoxic effect of Te.

Nitrosation of phenolic compounds: inhibition and enhancement

The nitrosation of phenol, m-, o-, and p-cresol, 2,3-, 3,5-, and 2, 6-dimethylphenol, 3,5-di-tert-butylphenol, 2,4,6-trimethylphenol, o-chlorophenol, and o-bromophenol was studied. Kinetic monitoring of the reactions was accomplished by spectrophotometric analysis of the products at 345 nm. At pH > 3, the dominant reaction was C-nitrosation through a mechanism that appears to consist of an attack on the nitrosatable substrate by NO(+)/NO(2)H(2)(+), followed by a slow proton transfer. The finding of an isokinetic relationship supports the idea that the same mechanism operates throughout the series. The observed sequence of nitrosatable substrate reactivities is explained by (i) the preferred para-orientation of the hydroxyl group for the electrophilic attack of nitrosating agents, (ii) steric hindrance of alkyl substituents, which reduces or prevents attack by nitrosating agents, and (iii) the hyperconjugative effect of the methyl substituent, which causes electronic charge to flow into the aromatic nucleus, as well as the opposite electronic withdrawing effect induced by halogen substituents. The results show that potential nitrosation of widespread environmental species such as chlorophenols is negligible, but more attention should be paid to polyphenols with strongly nucleophilic carbon atoms.

Activation of the autophagy, c-FOS and ubiquitin expression, and nucleolar alterations in Schwann cells precede demyelination in tellurium-induced neuropathy

We have used an experimental model of tellurium (Te)-induced demyelinating neuropathy in the rat to study cellular mechanisms involved in the early response of myelinating Schwann cells (SCs) to injury, prior to demyelination. Starting at postnatal day 21, weaned rats were fed a diet containing 1.1% elemental Te. The animals were killed daily within the 1st week of Te diet and the sciatic nerves were processed for the ultrastructural and immunocytochemical studies. Immunohistochemistry revealed that Te induces an increased nuclear expression of c-Fos in SCs. By electron microscopy analysis, the early cytoplasmic alteration was a dramatic disorganization of the rough endoplasmic reticulum (ER) with cisternal dilations and redistribution and loss of membrane-bound ribosomes. This was followed by a prominent activation of the macroautophagy in SCs. This process involved the formation of autophagosomes containing well-preserved cell organelles, autolysosomes with cellular remnants in various phases of degeneration and lysosomes. Te treatment also induced the expression of free ubiquitin in the perikaryal region of the SC cytoplasm. Immunogold electron microscopy showed the subcellular distribution of ubiquitin in the cytosol, around of dilated ER cisterns and in the matrix of autolysosomes and residual bodies. At the nucleolar level, fibrillarin immunofluorescence revealed nucleolar segregation in SCs exposed to Te. The ultrastructural study confirmed the segregation of the nucleolar components with a peripheral distribution of the dense fibrillar component. These results support the hypothesis that the depletion of cholesterol induced by Te treatment triggers a stress response in myelinating SCs mediated by immediate early genes of the fos family. The cellular response includes a severe disruption of the protein synthesis machinery, namely the rough ER and nucleolus, with the subsequent activation of both ubiquitin and autophagic pathways of proteins and cell organelle degradation. This cytoplasmic remodeling may represent a cytoprotective mechanism in the response of SCs to a neurotoxic stress. Furthermore, it must be a prerequisite for the induction of phenotypic changes and cell repair mechanisms in SCs.

Reactive gliosis of immature Bergmann glia and microglial cell activation in response to cell death of granule cell precursors induced by methylazoxymethanol treatment in developing rat cerebellum

The morphology, organization and expression of proliferating cell nuclear antigen (PCNA) and the cytoskeletal proteins vimentin and GFAP in immature Bergmann glial cells were studied after a developmental injury induced by a single dose of the cytotoxic agent methylazoxymethanol (MAM) administered on postnatal day 5. This drug, which produces cell death of cerebellar granule cell precursors, did not induce apoptosis in Bergmann glial cells, which are in a proliferative stage. After MAM treatment, PCNA staining showed a severe depletion of PCNA-positive granule cell precursors, whereas PCNA-positive Bergmann glial nuclei in the Purkinje cell layer were preserved. Moreover, the quantitative analysis revealed an increase in the density of both Purkinje cells and PCNA-positive Bergmann glial cells per mm of Purkinje cell layer in MAM-treated rats relative to age-matched controls, but the numerical ratio between these two cell populations remains invariable after MAM treatment. Vimentin and GFAP immunocytochemistry revealed a reinforcement of the Bergmann glial palisade with overexpression of both proteins and thicker immunoreactive glial processes in MAM-treated rats. At the ultrastructural level, Bergmann glial processes closely associated with dying cells in different stages of apoptosis were observed. Frequently, these processes enclosed dying cells in extracellular compartments. Furthermore, phagosomes containing apoptotic bodies were found in Bergmann fibers of MAM-treated rats. These data indicate that the cell death of granule cell precursors triggers a reactive response in immature Bergmann glia. We suggest that this response reflects the plasticity of Bergmann glia to control the neuronal microenvironment in the maturing molecular layer, protecting healthy cells against the potentially harmful contents of dying cells. In situ labeling of cell death with the TUNEL method revealed that the cell death of granule cell precursors is of the apoptotic type. The participation of ameboid microglial cells in the phagocytosis of apoptotic cells was shown with tomato lectin histochemistry and ultrastructural analysis. Moreover, the presence of mitosis in this microglial population demonstrates its proliferative activity in regions of extensive cell death.

Regulation of Schwann cell numbers in tellurium-induced neuropathy: apoptosis, supernumerary cells and internodal shortening

We have used an experimental model of tellurium(Te)-induced demyelinating neuropathy in the rat to study cellular mechanisms involved in regulating Schwann cell (SC) numbers during remyelination. Starting at postnatal day 21, weaned rats were fed a diet containing 1.1% elemental Te. Following 7 days of Te treatment and at several time points of post-tellurium treatment (PTe), the animals were processed for ultrastructural analysis, SC nuclei quantification and teased fibre preparations. It is well-established that Te induces a transient demyelinating/remyelinating sequence in sciatic nerves. The loss of the myelin sheath in this neuropathy produces active proliferation and overproduction of immature SCs. By electron microscopy analysis most mitotic SCs were located along demyelinated segments. Quantitative determination of SC nuclei per transverse section of sciatic nerve revealed a dramatic increase of SCs at 2 days PTe relative to control nerves. The number of SC nuclei then decreased progressively during the long-term period of recovery studied (330 days PTe). In Te-treated rats, SCs undergoing cell death were regularly found within the nerve fibre compartment, especially on demyelinated segments. Dying cells exhibited morphological features of apoptosis and appeared enclosed by lamellar processes of adjacent healthy SCs in extracellular compartments. Both healthy immature SCs and endoneurial macrophages were involved in the phagocytosis of apoptotic SCs. Particularly during remyelination, supernumerary endoneurial SCs were observed surrounding myelinated fibres. These cells progressively became atrophic with a morphological phenotype similar so that of "onion bulb" cells. On the other hand, teased fibre measurements revealed a remarkable permanent internodal shortening in remyelinated fibres from Te-treated sciatic nerves. These results indicate that a portion of redundant immature SCs are susceptible to elimination by apoptosis. However, other distinct biological mechanisms such as the persistence of supernumerary SCs in the endoneurium and the shortening of internodal lengths are also involved in regulating SC numbers during the remyelination stage.

Fulminant Guillain-Barré syndrome with universal inexcitability of peripheral nerves: a clinicopathological study

The pathological basis of nerve inexcitability in Guillain-Barré syndrome has not been established with certainty. We report the clinicopathological findings in a 67-year-old patient with fulminant Guillain-Barré syndrome who died 18 days after onset. Three serial electrophysiological studies revealed nerve inexcitability. Antibodies to Campylobacter jejuni were present but there was no antiganglioside reactivity. Spinal root sections revealed extensive and almost pure macrophage-associated demyelination with occasional presence of T lymphocytes and neutrophil leukocytes. Conversely, in femoral, median, and sural nerves the outstanding lesion was axonal degeneration, with some denuded axons remaining. Unmyelinated fibers, posterior root ganglia, and dorsal columns were preserved. Endoneurial postcapillary venules showed plump endothelial cells with loss of their tight junctions. We conclude that both primary demyelination and axonal degeneration secondary to inflammation account for nerve inexcitability. Our findings lend support to the hypothesis of increased endoneurial pressure as the cause of wallerian degeneration in nerve trunks.

Apoptosis induced by methylazoxymethanol in developing rat cerebellum: organization of the cell nucleus and its relationship to DNA and rRNA degradation

We present a cytological and biochemical study of the cell death of granule cell precursors in developing rat cerebellum following treatment with the cytotoxic agent methylazoxymethanol (MAM) during the first postnatal week. The density of apoptotic figures per square millimeter progressively increases after 6, 12, 24 and 44 h of treatment, whereas cells immunoreactive for proliferating cell nuclear antigen tend to disappear in the external granular layer (EGL). DNA migration on gel electrophoresis reveals a typical ladder pattern of internucleosomal cleavage following MAM treatment, whereas gel electrophoresis of rRNA shows a conspicuous degradation of both 28S and 18S rRNAs. Ultrastructural analysis has revealed the alterations of structures containing chromatin and ribonucleoprotein (RNP) in dying cells of the EGL. The typical granular beaded configuration of the condensed chromatin changes to a denser, more homogeneous texture suggesting nucleosomal disruption. The reorganization of RNP nuclear domains is reflected by the appearance of dispersed nucleoplasmic RNP particles and the formation of a coiled-body-like structure. However, typical nuclear domains involved in the splicing of RNAs, namely interchromatin granule clusters and typical "coiled bodies", are not found in apoptotic cells. Intranuclear bundles of filaments have also been detected. In the cytoplasm, the presence of dispersed single ribosomes is an initial sign of apoptosis. The massive dispersion and disruption of ribosomes detected after 24 h and 44 h of MAM treatment is reflected by the degradation of both 28S and 18s rRNAs. These results show that MAM treatment provides a useful experimental model for the study of apoptosis in the developing central nervous system. The organization of the cell nucleus in cells undergoing apoptosis clearly reflects a disruption of the nuclear compartments involved in transcription and the processing and transport of RNA and is related to the patterns of DNA and rRNA degradation.

Breast cancer mortality in relation to self-reported use of breast self-examination. A cohort study of 450,000 women

The benefits of breast self-examination (BSE) for reducing mortality from breast cancer are uncertain. We conducted an analysis of the relationship between self-reported practicing of BSE and mortality from breast cancer over 13 years in a cohort of over 548,000 women. The report of practicing BSE was unrelated to breast cancer mortality. There was a small beneficial effect in those women who were the thinnest, but this effect was small and not statistically significant. BSE was otherwise equally ineffective in subgroups defined by obesity level and family history of breast cancer. We conclude that BSE, as practiced by American women in 1959, did not reduce the risk of mortality from breast cancer.

Schwann cell nuclear remodelling and formation of nuclear and coiled bodies in Guillain-Barré syndrome

We have examined the reorganization of the cell nucleus in myelin-related Schwann cells (SCs) in a case of acute Guillain-Barré syndrome (GBS). Spinal root samples of the GBS case and human controls were processed for light and electron microscopy. The cytochemical EDTA method for ribonucleoproteins (RNPs) and a specific silver staining technique for nucleolar organizer regions were used on ultrathin sections. In SCs of the GBS case, we observed a significant increase in nuclear size (64.99 +/- 10.47 microns 2 in the GBS vs 35.07 +/- 8.74 microns 2 in the controls, mean +/- SD) accompanying partial decondensation of heterochromatin domains and elaboration of an extensive network of RNP-containing perichromatin fibrils. In addition, the formation of two types of nuclear structures, coiled bodies and nuclear bodies of Bouteille, was induced in SCs of the case of acute GBS. Free coiled bodies were observed in the nucleoplasm and were characteristically stained with both RNP and silver procedures. Typical "simple" and "complex" nuclear bodies were regularly found, sometimes in association with coiled bodies. On the basis of cell nucleus physiology, all of these changes are considered cytological indicators of enhanced transcription and cellular hyperactivity, and they seem to reflect a reactive response of SCs triggered by the constellation of cellular and humoral signals associated with acute GBS.

[Upper digestive hemorrhage in the inhabitants of high altitudes in Peru]

One hundred cases of upper gastrointestinal hemorrhage in peruvian highlanders were studied at a hospital in La Oroya (3850 meters above the sea level). On admission in all of them an esophagogastroduodenal fiberscope was performed to establish the diagnosis. Most of them were males (98%), between 30-39 years of age (38%) and presented at the same time hematemesis and melena (64%). After bleeding in 72% the hemoglobin was over 14 g%. As a whole the most frequent diagnosis were: gastric ulcer (33%). duodenal ulcer (23%) and erosive gastritis (23%). In those living between 3000-3500 m.a.s.l. duodenal ulcer had the highest incidence. At 3500 m.a.s.l. was gastric ulcer more frequent, followed by erosive gastritis. In 11% surgery was required and only in 27% it was necessary a blood transfusion. After bleeding 10% had an hemoglobin level over 20 g% and because of this they were considered as having Chronic Mountain Sickness, 4 of them with severe cardiorespiratory and consciousness disturbances required after the gastrointestinal hemorrhage, an immediate bleeding in order to compensate the patient, a completely unusual occurrence in general pathology but a peculiar treatment in these patients living at high altitudes of the peruvian Andes.

Age-induced hypertrophy of astrocytes in rat supraoptic nucleus: a cytological, morphometric, and immunocytochemical study

BACKGROUND

In the adult rat, neuron-astroglia interactions in the supraoptic nucleus (SON) are characterized by the structural and functional plasticity of astrocytes in response to several physiological and experimental conditions. This study has analyzed the plasticity of the supraoptic nucleus astrocytes in response to the age-induced changes in neuronal activity.

METHODS

The study was performed in 5-, 12-, 18- and 24-month-old rats. The cytology and organization of astrocytes in the SON were examined using glial fibrillary acidic and vimentin immunocytochemistry and ultrastructural and morphometric analysis.

RESULTS

No significant age-related variations in the total number of neurons and astrocytes in the SON were detected, although a few degenerating neurons were found in old rats. An age-dependent increase in GFAP immunoreactivity was observed at the ventral glial lamina, perivascularly and between neuronal perikarya. Vimentin overexpression was also detected in ventral lamina astrocytes with advancing age. At the cell nucleus level, we observed an age-associated increase in nuclear size and in the number of coiled bodies, nuclear bodies, and "cleared" nucleoplasmic areas, as well as changes in the nucleolar organization. At the cytoplasmic level, characteristic ultrastructural features in astrocytes of old rats were the hypertrophy of intermediate filament bundles and the formation of an extensive network of Golgi stacks interlinked by tubulovesicular elements. Glial filaments were often associated with the nuclear envelope and polyribosomes.

CONCLUSIONS

The increased GFAP and vimentin immunoreactivity and the morphometric and cytological changes in rat SON astrocytes may reflect a sustained upregulation of cellular activity with age, resulting in hypertrophy of glial perikarya and cell processes. Several factors that are known to influence the expression of the astrocytic phenotype, such as signals produced by degenerating neurons and activated microglia, as well as variations in neuronal activity are considered possible causes of the age-associated changes in SON astrocytes.

Parental age and breast cancer mortality

Because older ages of both mothers and fathers have been hypothesized by others to increase the subsequent risk of breast cancer in female babies, we analyzed the association between maternal and paternal age at birth and mortality from breast cancer in a cohort of 384,796 American women. Cox proportional hazards modeling accounted for age, family history of breast cancer in first-degree relatives, age at menarche, age at first pregnancy, and parity. We found little association between paternal age at birth and death from breast cancer. Although there was no clear linear trend for higher risk with increasing age of the mothers at birth, women born to mothers age 45 years or older had a relative hazard of 1.30 (95% confidence interval = 0.85-1.98), compared with women born to mothers under the age of 20 years. Although these findings are of little public health significance, they may indicate a hormonal profile in older mothers that predisposes female offspring to a higher risk of breast cancer in later years.

Adjusting risk factors in spontaneous abortion by multiple logistic regression

A cross-sectional case-control study was performed to identify some obstetric and gynaecologic factors that can influence spontaneous abortion. Statistical and epidemiologic analyses were done by multiple logistic regression to adjust OR through the beta coefficient. A dicotomized outcome variable, representing spontaneous abortion, and different independent variables, representing distinct medical factors, were designed. The analysis was carried out with a personal computer and an appropriate statistic package. The variables representing age over 35 and previous spontaneous abortions were shown to be risk factors, adjusted for the rest of variables. The variables representing parity and late menarcheal age lost significance when they were adjusted with multiple logistic regression.