Observation of the suppression of the flux of cosmic rays above 4 x 10 (19) eV

The energy spectrum of cosmic rays above 2.5 x 10;{18} eV, derived from 20,000 events recorded at the Pierre Auger Observatory, is described. The spectral index gamma of the particle flux, J proportional, variantE;{-gamma}, at energies between 4 x 10;{18} eV and 4 x 10;{19} eV is 2.69+/-0.02(stat)+/-0.06(syst), steepening to 4.2+/-0.4(stat)+/-0.06(syst) at higher energies. The hypothesis of a single power law is rejected with a significance greater than 6 standard deviations. The data are consistent with the prediction by Greisen and by Zatsepin and Kuz'min.

Upper limit on the diffuse flux of ultrahigh energy tau neutrinos from the Pierre Auger Observatory

The surface detector array of the Pierre Auger Observatory is sensitive to Earth-skimming tau neutrinos that interact in Earth's crust. Tau leptons from nu(tau) charged-current interactions can emerge and decay in the atmosphere to produce a nearly horizontal shower with a significant electromagnetic component. The data collected between 1 January 2004 and 31 August 2007 are used to place an upper limit on the diffuse flux of nu(tau) at EeV energies. Assuming an E(nu)(-2) differential energy spectrum the limit set at 90% C.L. is E(nu)(2)dN(nu)(tau)/dE(nu)<1.3 x 10(-7) GeV cm(-2) s(-1) sr(-1) in the energy range 2 x 10(17) eV< E(nu)< 2 x 10(19) eV.

Ulcerated sclerotic giant congenital melanocytic naevus: case report and review of the literature

We report a case of a white girl with an ulcerated giant congenital melanocytic naevus that initially had a hard, stony consistency but in which the pigmentation and the induration are progressively vanishing. Very few cases of this variant of GCMN, known as sclerodermoid GCMN or desmoplastic hypopigmented hairless naevus, have been reported to date, and clinical evolution seems to be heterogeneous. We review the published cases and propose the term 'sclerotic hypopigmented GCMN as a common descriptor of this type of congenital melanocytic naevus.

Hormonal differences between psychotic and non-psychotic melancholic depression

BACKGROUND

The dexamethasone suppression test (DST) is the main hormonal disturbance in psychotic depression compared to non-psychotic depression. However, although there have been many studies of individual hormonal axes in depression, few multi-axial studies have been reported. This study aims to examine hormonal differences between these groups of patients through three functional hormonal tests: DST, thyroid stimulating hormone response to thyroid releasing hormone (TSH-TRF) and growth hormone response to growth hormone releasing factor (GH-GRF).

METHODS

Forty inpatients meeting DSM-III-R criteria for major depressive episode with melancholia (21 non-psychotic and 19 psychotic) were studied. Dexamethasone suppression test, TSH-TRF and GH-GRF tests were undertaken for all patients.

RESULTS

In the whole melancholic sample, 80.0% showed disturbances in at least one hormonal axis, 40.0% in two axes and 5.0% in all three axes. Basal and post-dexamethasone cortisol levels were significantly higher in psychotic than in non-psychotic patients. An association between post-dexamethasone cortisol and blunted GH-GRF response was demonstrated in those with psychotic depression. In the whole sample, GH blunting was found in 62.5% of patients, DST non-suppression in 37.5% and TSH blunting in 25.0% (no differences were found between psychotic and non-psychotic patients).

LIMITATIONS

Sample was restricted to melancholia and unknown factors may influence hormonal responses to stress.

CONCLUSIONS

Hormonal disturbances in depression are more evident when studying several axes, being the HPA and the GH axes the most prominents. Psychotic depression showed more HPA disturbance than non-psychotic depression. Influence of the HPA on the GH axis is discussed.

Atmospheric mercury emissions from polluted gold mining areas (Venezuela)

Soil, waste rock and mud from mercury-gold amalgamation mining areas of El Callao (Venezuela) are highly enriched in Hg (0.5-500 microg g(-1)) relative to natural background concentrations (<0.1 microg g(-1)). Mercury fluxes to the atmosphere from twelve polluted sites of this area were measured in situ (6 a.m. to 8 p.m.) using a Plexiglas flux chamber connected to a portable mercury analyzer (model RA-915+; Lumex, St. Petersburg, Russia). Mercury fluxes ranged between 0.65 and 420.1 microg m(-2) h(-1), and the average flux range during the diurnal hours was 9.1-239.2 microg m(-2) h(-1). These flux values are five orders of magnitude higher than both reported world background Hg fluxes (1-69 ng m(-2) h(-1)) and the regional values, which are in the range 2-10 ng m(-2) h(-1). The flux results obtained in this study are, however, similar to those measured at Hg polluted sites such as chloro-alkali plants or polymetallic ore mining districts (>100,000 ng m(-2) h(-1)). The results from this study also show that Hg emissions from the soil are influenced by solar radiation, soil temperature and soil Hg concentration. Our data suggest that solar radiation may be the dominant factor affecting Hg degrees emission since the major species of mercury in polluted soil is Hg degrees (85-97% of total Hg). The simple release of Hg degrees vapor is probably the dominant process occurring with incident light in the field. The apparent activation energy for mercury emission indicates that the volatilization of mercury mainly occurred as a result of the vaporization of elemental mercury in soil. The degree of Hg emission differed significantly among the soil sites studied, which may be due to variations in soil texture, organic matter content and soil compaction.

Loss of the circadian variation of platelet [3H]imipramine binding in delusional compared with non-delusional endogenously depressed patients

BACKGROUND

The circadian variations of the serotonin reuptake sites were studied in 16 patients meeting DSM-IV criteria for major depression with melancholia, either with (n=8) or without (n=8) psychotic symptomatology.

METHOD

The [3H]imipramine binding sites were measured in platelet samples.

RESULTS

While no statistically significant difference was found between the morning (09:00 h) and evening (21:00 h) [3H]imipramine B(max) values in the control group, both the non-delusional and delusional melancholic patients showed higher evening than morning B(max) values, which were only statistically significant in the former. When both diagnostic groups were compared, the delusional patients showed significantly lower [3H]imipramine binding values than the non-delusional patients both in the morning and evening samples. Within the non-delusional depressed patients, those individuals with mood circadian variation, assessed by the 18th item of the HDRS, showed significantly lower B(max) values than those without mood variation. Lowest morning and evening B(max) values were noted in the delusional depressed group without mood variations.

CONCLUSIONS

These results suggest that delusional depressions might have a different neurobiological substrate with loss of chronobiological rhythms.

Dopamine, hypertension and obesity

Dopamine, a neurotransmitter, precursor of noradrenaline, is responsible for cardiovascular and renal actions, such as increase in myocardial contractility and cardiac output, without changes in heart rate, producing passive and active vasodilatation, diuresis and natriuresis. These cardiovascular and renal actions take place through the interaction with dopamine receptors, D(1), D(2), D(3), D(4), and D(5). Recent findings point to the possibility of D(6) and D(7)receptors. Dopamine is known to influence the control of arterial pressure by influencing the central and peripheral nervous system and target organs such as kidneys and adrenal glands, in some types of hypertension. Although dopamine and its derivatives have been shown to have antihypertensive effects, these are still being studied; therefore it is important to explain some physiological and pharmacological aspects of dopamine, its receptors, and the clinical uses it could have in the treatment of arterial hypertension and more recently in obesity, based on evidence proving a clear association between obesity and the decrease in the expression of D(2) receptors in the brain of obese persons.

beta-catenin expression in pilomatrixomas. Relationship with beta-catenin gene mutations and comparison with beta-catenin expression in normal hair follicles

BACKGROUND

beta-catenin functions in signal transduction in the Wnt signalling pathway, which has recently been implicated in hair follicle (HF) morphogenesis. beta-catenin gene mutations affecting exon 3 have been reported in a high percentage of human pilomatrixomas. However, the expression pattern of beta-catenin in human HFs and pilomatrixomas has not been reported.

OBJECTIVES

To analyse immunohistochemically the expression pattern of beta-catenin in normal anagen HFs and in 40 human pilomatrixomas.

METHODS

In 11 of these tumours we also studied exon 3 beta-catenin gene mutations by polymerase chain reaction and direct sequencing. As these mutations have been related to a replication error (RER) phenotype in other tumour types, we explored whether or not this association also occurs in pilomatrixomas.

RESULTS

beta-catenin was expressed in the cell membranes of the outer and inner root sheaths and in matrix cells located at the base and periphery of the HF bulb. However, central matrix cells that differentiate into cortical cells, cortical and cuticular cells expressed beta-catenin in the nucleus, suggesting a role in signal transduction. In addition, some fibroblasts of the dermal papilla also showed nuclear expression of beta-catenin. All 40 analysed pilomatrixomas showed intense nuclear and cytoplasmic beta-catenin expression in proliferating matrix (basaloid) cells. In areas of maturation, transitional cells mainly showed cytoplasmic and membranous expression of beta-catenin, while only a few cells retained nuclear expression. Shadow or ghost cells did not show beta-catenin expression. Three of 11 tumours (26%) had beta-catenin mutations. All three had the same heterozygote mis-sense mutation: a G to T change affecting the first nucleotide at codon 32 (D32Y). None of the 11 tumours studied had a positive RER phenotype.

CONCLUSIONS

Present and previous studies suggest that the Wnt/beta-catenin/Tcf-Lef pathway is activated in normal matrix cells of the HF to induce differentiation to the hair shaft. Additionally, the beta-catenin mutation in matrix cells of the HF stabilizes beta-catenin protein, which translocates into the nucleus, where it activates of gene transcription together with lymphoid enhancer factor-1 producing pilomatrixoma. These mutations occur without an underlying defect in DNA mismatch repair.

Pilomatrix carcinoma: a clinicopathologic study of six cases and review of the literature

Pilomatrix carcinoma, the malignant variant of pilomatrixoma, is a rare entity. The authors report on six patients with pilomatrix carcinoma and review the pertinent literature. The lesions showed a predilection for elderly individuals (mean age, 61 years) with a male:female ratio of 5:1, and they presented as dermal or subcutaneous tumors located on the head and neck (5 neoplasms) and chest (1 neoplasm). Tumors varied in size from 0.6 cm to 2.5 cm (mean, 1.78 cm). None of the lesions recurred after wide local excision. On scanning magnification, all tumors showed the architectural features of a malignant neoplasm (asymmetry and poor circumscription, presence of several markedly sized and variably shaped basaloid aggregations, and ulceration). The tumors were composed of pleomorphic basaloid cells with prominent nucleoli and frequent atypical mitoses accompanied by central areas with keratotic material, shadow cells, and foci of necrosis. The tumor nests were surrounded by a desmoplastic stroma and infiltrated the adjacent tissues. Vascular or perineural infiltration was not observed. In one case, the basaloid cells contained abundant melanin pigment in their cytoplasms. Pilomatrix carcinoma is a neoplasm of low-grade malignancy that should be distinguished from the conventional pilomatrixoma and its variants (aggressive pilomatrixoma and proliferating pilomatrixoma), matricoma, and basal cell carcinoma with matrical differentiation. Clinicians and pathologists should be aware of the occurrence of pilomatrix carcinoma because of its potential for distant metastases.

Olmsted syndrome

Olmsted syndrome is an uncommon inherited disorder of keratinization that presents mutilating palmoplantar keratoderma, perioral hyperkeratosis, leukokeratosis and alopecia. We report a case of this rare syndrome diagnosed in a 48-year-old woman and confirms the existence of a generalized abnormality in keratin expression. Immunoreactivity in our case suggests an abnormal expression of keratins 5 and 14 similar to the observed in other hyperproliferative disorders.

Metabolism and growth of juveniles of Litopenaeus vannamei: effect of salinity and dietary carbohydrate levels

The present study was designed to understand how carbohydrate (CBH) and protein metabolism are related in the penaeid shrimp Litopenaeus vannamei. With this information, we obtained a comprehensive schedule of the protein-carbohydrate metabolism including enzymatic, energetic, and functional aspects. We used salinity to determine its role as a modulator of the protein-carbohydrate metabolism in shrimp. Two experiments were designed. The first experiment evaluated the effect of CBH-salinity combinations in growth and survival, and hemolymph glucose, protein, and ammonia levels, digestive gland glycogen, osmotic pressure, and glutamate dehydrogenase (GDH) of L. vannamei juveniles acclimated during 18 days at a salinity of 15 per thousand and 40 per thousand. The second experiment was done to evaluate the effect of dietary CBH level on pre- and postprandial oxygen consumption, ammonia excretion, and the oxygen-nitrogen ratio (O/N) of juvenile L. vannamei in shrimps acclimated at 40 per thousand salinity. We also evaluated the ability of shrimp to carbohydrate adaptation. We made phosphoenolpyruvate carboxykinase (PECPK) and hexokinase activity measurements after a change in dietary carbohydrate levels at different times during 10 days. The growth rate depended on the combination salinity-dietary CBH-protein level. The maximum growth rate was obtained in shrimps maintained at 15 per thousand salinity and with a diet containing low CBH and high protein. The protein in hemolymph is related to the dietary protein levels; high dietary protein levels produced a high protein concentration in hemolymph. This suggests hemolymph is able to store proteins after a salinity acclimation. Depending on the salinity, the hemolymph proteins could be used as a source of osmotic effectors or as metabolic energy. The O/N values obtained show that shrimp used proteins as a source of energy, mainly when shrimps were fed with low CBH. The role played by postprandial nitrogen excretion (PPNE) in apparent heat increase (AHI) (PPNE/AHI ratio) is lower in shrimps fed diets containing high CBH in comparison with shrimps fed diets containing low CBH levels. These results confirm that the metabolism of L. vannamei juveniles is controlled by dietary protein levels, affecting the processes involved in the mechanical and biochemical transformations of ingested food. A growth depression effect was observed in shrimps fed with low-CBH protein diets and maintained in 40 per thousand salinity. In these shrimps, the hemolymph ammonia concentration (HAC) was significantly higher than that observed in shrimps fed with low CBH and maintained in 15 per thousand salinity. That high HAC level coincided with lower growth rate, which suggests that this level might be toxic for juveniles of L. vannamei. Results obtained for GDH activity showed this enzyme regulated both HAC and hemolymph protein levels, with high values in shrimps fed with low CBH levels and maintained in 40 per thousand salinity, and lower in shrimps fed with high CBH and maintained in 15 per thousand salinity. These differences mean that shrimp with a high-gill GDH activity might waste more energy in oxidation of the excess proteins and amino acids, reducing the energy for growth. It was evident that L. vannamei can convert protein to glycogen by a gluconeogenic pathway, which permitted shrimp to maintain a minimum circulating glucose of 0.34 mg/ml in hemolymph. A high PECPK activity was observed in shrimps fed a diet containing low CBH level indicating that the gluconeogenic pathway is activated, as in vertebrates by low dietary CBH levels. After a change in diet, we observed a change in PEPCK; however, it was lower and seems to depend on the way of adaptation, because it occurred after 6 days when adapting to a high-CBH diet and with little change for the low-CBH diet.

Two cases of segmental multiple glomangiomas in a family: type 1 or type 2 segmental manifestation?

Several autosomal dominant skin diseases may manifest cutaneous mosaicism. Two types of segmental arrangement can be distinguished: type 1 is characterized by segmental lesions with similar severity to that observed in the diffuse phenotype, the remaining skin being normal; type 2 is characterized by segmental lesions showing a major degree of severity and milder lesions diffusely arranged. Multiple glomus tumours have recently been included in the group of genodermatoses showing type 2 segmental involvement. A family with 2 cases of multiple glomangiomas arranged in a segmental fashion is reported. A 12-year-old girl presented multiple nodular glomangiomas on her right buttock and thigh, in a band-like distribution. A sister of her paternal grandfather showed plaque-like multiple glomangiomas on her left thigh and various glomangiomas on her right buttock and arm. No other family members were known to be affected. Two new cases of familial segmental multiple glomangiomas are reported, with the particularity that one of these exhibited type 2 segmental manifestation and the other type 1 from a clinical point of view.

Endothelial dysfunction in arterial hypertension

Systemic arterial pressure is a dynamic and reactive physiological parameter depending on a great many factors. The endothelial cells of the vascular system are responsible for many biochemical reactions maintaining vascular homeostasis and therefore arterial pressure. Arterial hypertension, atherosclerosis and endothelial dysfunction constitute risk factors increasing morbidity and mortality of cardiovascular origin. These three elements are closely related and frequently act simultaneously damaging different organs. In this paper we review the physiology of the endothelium and the probable consequences of endothelial dysfunction on the pathophysiology of arterial pressure.

Diabetes and hypertension physiopathology and therapeutics

Diabetes mellitus by itself, is a frequent and increasing public health problem. The prevalence in most Western countries varies between 2 to 5% and it is rapidly increasing in Asiatic countries due to changes in dietary habits during the last years. The association between diabetes mellitus and hypertension has been described in 60 to 65% of diabetics. In hypertension we find insulin resistance mainly in skeletal muscle involving the conversion of glucose to glycogen independently of blood flow. The degree of resistance is related to the severity of hypertension and varies between races. States of hyperinsulinaemia and insulin-resistance have been postulated as causes and/or consequences of hypertension. Regardless of the type of diabetes, hypertension is two to three times more common among diabetics compared with non-diabetics. In this paper we propose to review the essential physiopathological mechanisms involved in this association that causes high morbidity and mortality rates and increases disability among the population involved.

Syphilis in an HIV infected patient misdiagnosed as leprosy

A 42-year-old man with uveitis and a widespread cutaneous eruption, histopathologically characterized by dermal granulomatous infiltrates with perineurial invasion, was incorrectly diagnosed and treated as having borderline leprosy. Further studies demonstrated secondary syphilis and human immunodeficiency virus (HIV) infection. Standard penicillin therapy resolved his cutaneous and ocular lesions. Reports on clinical and pathological findings of active syphilis in HIV infected patients are scarce but this case and isolated previous case reports suggest that granulomatous infiltrates might be a common feature in secondary syphilis with short evolution in HIV infected patients.