Gas phase Elemental abundances in Molecular cloudS (GEMS) II. On the quest for the sulphur reservoir in molecular clouds: the H2S case.

CONTEXT: Sulphur is one of the most abundant elements in the Universe. Surprisingly, sulphuretted molecules are not as abundant as expected in the interstellar medium and the identity of the main sulphur reservoir is still an open question. AIMS: Our goal is to investigate the H2S chemistry in dark clouds, as this stable molecule is a potential sulphur reservoir. METHODS: Using millimeter observations of CS, SO, H2S, and their isotopologues, we determine the physical conditions and H2S abundances along the cores TMC 1-C, TMC 1-CP, and Barnard 1b. The gas-grain model Nautilus is used to model the sulphur chemistry and explore the impact of photo-desorption and chemical desorption on the H2S abundance. RESULTS: Our modeling shows that chemical desorption is the main source of gas-phase H2S in dark cores. The measured H2S abundance can only be fitted if we assume that the chemical desorption rate decreases by more than a factor of 10 when n H > 2 × 104. This change in the desorption rate is consistent with the formation of thick H2O and CO ice mantles on grain surfaces. The observed SO and H2S abundances are in good agreement with our predictions adopting an undepleted value of the sulphur abundance. However, the CS abundance is overestimated by a factor of 5 - 10. Along the three cores, atomic S is predicted to be the main sulphur reservoir. CONCLUSIONS: The gaseous H2S abundance is well reproduced, assuming undepleted sulphur abundance and chemical desorption as the main source of H2S. The behavior of the observed H2S abundance suggests a changing desorption efficiency, which would probe the snowline in these cold cores. Our model, however, highly overestimates the observed gas-phase CS abundance. Given the uncertainty in the sulphur chemistry, we can only conclude that our data are consistent with a cosmic elemental S abundance with an uncertainty of a factor of 10.

Gas phase Elemental abundances in Molecular cloudS (GEMS): I. The prototypical dark cloud TMC 1.

GEMS is an IRAM 30m Large Program whose aim is determining the elemental depletions and the ionization fraction in a set of prototypical star-forming regions. This paper presents the first results from the prototypical dark cloud TMC 1. Extensive millimeter observations have been carried out with the IRAM 30m telescope (3 mm and 2 mm) and the 40m Yebes telescope (1.3 cm and 7 mm) to determine the fractional abundances of CO, HCO+, HCN, CS, SO, HCS+, and N2H+ in three cuts which intersect the dense filament at the well-known positions TMC 1-CP, TMC 1-NH3, and TMC 1-C, covering a visual extinction range from A V ~ 3 to ~20 mag. Two phases with differentiated chemistry can be distinguished: i) the translucent envelope with molecular hydrogen densities of 1-5×103 cm-3; and ii) the dense phase, located at A V > 10 mag, with molecular hydrogen densities >104 cm-3. Observations and modeling show that the gas phase abundances of C and O progressively decrease along the C+/C/CO transition zone (A V ~ 3 mag) where C/H ~ 8×10-5 and C/O~0.8-1, until the beginning of the dense phase at A V ~ 10 mag. This is consistent with the grain temperatures being below the CO evaporation temperature in this region. In the case of sulfur, a strong depletion should occur before the translucent phase where we estimate a S/H ~ (0.4 - 2.2) ×10-6, an abundance ~7-40 times lower than the solar value. A second strong depletion must be present during the formation of the thick icy mantles to achieve the values of S/H measured in the dense cold cores (S/H ~8×10-8). Based on our chemical modeling, we constrain the value of ζ H2 to ~ (0.5 - 1.8) ×10-16 s-1 in the translucent cloud.

Sphere-Tubule Superstructures through Supramolecular and Supracolloidal Assembly Pathways.

While colloids have been widely employed as models for atoms and molecules, the current study proposes to extend their use as building blocks for supracolloidal frameworks. Hereby, the self-assembly between highly anisotropic supramolecular microtubules and soft spherical fluorescent microgels is explored using confocal laser scanning microscopy. The influence of the particle size and charge with respect to the catanionic tubule composition, which consists of two oppositely charged bile salt derivatives, is investigated. Under certain conditions, microgel particles are found to specifically interact with the extremities of the tubular aggregates and hierarchically self-assemble into various superstructures varying from virus-like assemblies to supracolloidal networks. The reported approach is envisioned to open new self-assembly routes toward ordered hybrid superstructures where the spherical colloids act as responsive linkers of tubular structures.

The pure rotational spectrum of HPS (X̃1A'): chemical bonding in second-row elements.

The pure rotational spectrum of HPS, as well as its (34)S and D isotopologues, has been recorded at microwave, millimeter, and submillimeter wavelengths, the first observation of this molecule in the gas phase. The data were obtained using a combination of millimeter direct absorption, Fourier transform microwave (FTMW), and microwave-microwave double-resonance techniques, which cover the total frequency range from 15 to 419 GHz. Quantum chemical calculations at the B3LYP and CCSD(T) levels were also performed to aid in spectral identification. HPS was created in the direct absorption experiment from a mixture of elemental phosphorus, H(2)S, and Ar carrier gas; DPS was produced by adding D(2). In the FTMW study, these species were generated in a pulsed discharge nozzle from PH(3) and H(2)S or D(2)S, diluted in neon. The spectra recorded for HPS and its isotopologues exhibit clear asymmetric top patterns indicating bent structures; phosphorus hyperfine splittings were also observed in HPS, but not DPS. Analysis of the data yielded rotation, centrifugal distortion, and phosphorus nuclear spin-rotation parameters for the individual species. The r(m) ((1)) structure for HPS, calculated from the rotational constants, is r(H-P) = 1.438(1) Å, r(P-S) = 1.9320(1) Å, and θ(H-P-S) = 101.85(9)°. Empirically correcting for zero-point vibrational effects yields the geometry r(e)(H-P) = 1.4321(2) Å, r(e)(P-S) = 1.9287(1) Å, and θ(e)(H-P-S) = 101.78(1)°, in close agreement with the r(m) ((1)) structure. A small inertial defect was found for HPS indicating a relatively rigid molecule. Based on these data, the bonding in this species is best represented as H-P=S, similar to the first-row analog HNO, as well as HNS and HPO. Therefore, substitution of phosphorus and sulfur for nitrogen and oxygen does not result in a dramatic structural change.

Oral histoplasmosis associated with HIV infection: a comparative study.

OBJECTIVE: Histoplasmosis is a granulomatous fungal disease caused by Histoplasma capsulatum. The objective of the present paper was to describe the prevalence of oral histoplasmosis (OH) in two services from an endemic area in Argentina between 1991 and 2002 and to compare the clinicopathological profile of OH between HIV-positive and HIV-negative patients. METHODS: About 733 HIV+ (group A) and 14 260 patients (group B) were examined. Clinical diagnosis was confirmed by cytology, biopsy or culture. RESULTS: About 21 (3%) and 10 (0.07%) cases of OH were diagnosed in group A and B respectively. Most patients were male. A total of 90% of patients in group A were <45 years old whereas 70% of group B were more than 45 years old. Palate, gingiva and oropharynx were the most frequent locations. The importance of including histoplasmosis in the differential diagnosis of ulcerated oral lesions in immunocompromised patients was discussed.

In vitro secretion of interleukin-1 beta and interferon-gamma by peripheral blood lymphomononuclear cells in diabetic patients.

There is evidence that cytokines, in particular interleukin-1 beta (IL-1 beta) and interferon-gamma (IFN-gamma) might mediate beta cell destruction in type 1 diabetes. Therefore the secretion of these cytokines by peripheral blood lymphomononuclear cells (PBMNC) was investigated in basal conditions and 48 h after stimulation with T-cell mitogen phytohaemagglutinin (PHA) in 33 diabetic patients and in 10 normal controls. The patients were divided in 4 groups (Group 1, 10 controls; Group 2, 13 newly diagnosed type 1 diabetics, the onset had occurred from 5 days to 3 months before the study; Group 3, 10 Long Standing (LS) type 1 diabetics with duration of the disease between 2 years and 10 years; and Group 4, 10 type 2 diabetics). No difference was found among the 4 groups considered in IL-1 beta secretion by unstimulated cultures, although the percentage of TAC+ cells was significantly higher in type 1 newly diagnosed diabetic patients with respect to the LS, the type 2 diabetics and the controls. After PHA stimulation a significant increase of IL-1 beta was found in newly diagnosed type 1 diabetic patients in comparison with the control subjects, the LS and type 2 diabetic patients (P < 0.001). The supernatants of newly diagnosed type 1 diabetics also showed a significant reduction in IFN-gamma production both in basal (P < 0.01) and in stimulated conditions (P < 0.001) in comparison with the controls, the LS (P < 0.002 in basal, and P < 0.001 in stimulated conditions) and the type 2 diabetic patients (P < 0.001 both in basal and stimulated conditions).(ABSTRACT TRUNCATED AT 250 WORDS)

In search of predictive markers of remission from insulin dependence in type 1 diabetes: a preliminary report.

We studied 18 newly diagnosed diabetic patients (8 males and 10 females, aged 18-26 years, within 10-120 days from the onset of symptoms) who were submitted for 15 days to intensive insulin therapy performed via subcutaneous insulin infusion (CSII). We investigated some metabolic and immunological parameters in order to identify a possible marker to predict the selection of patients potentially more responsive to CSII treatment for the remission of type 1 diabetes. In accordance with the International Diabetes Immunology Group we considered clinical remission as being the withdrawal of insulin therapy for at least 3 months. In order to assess beta-cell function a fasting and post-prandial serum C-peptide, blood glucose and HbA1c were performed on all patients before, and 3 days after, the discontinuation of CSII. Islet cell antibodies were determined in all sera by indirect immunofluorescence. Analysis of T-lymphocyte subpopulations was carried out before starting the therapy. The following monoclonal antibodies were used: CD4, CD8, CD57, CD25, HLA-DR. The levels of C3 and C4 and serum IgG, IgA and IgM were also evaluated. After CSII, 11 of 18 patients showed remission. At the beginning of the study we observed no major difference in metabolic parameters between the two groups. Interestingly, the patients who exhibited remission presented a statistically higher percentage of positive cells for CD57, HLA-DR and CD25 surface antigens, significantly lower C4 levels and CD4/CD8 ratio and significantly higher IgG levels compared with patients who did not show any remission.(ABSTRACT TRUNCATED AT 250 WORDS)

Extreme insulin resistance due to anti-insulin receptor antibodies: a direct demonstration of autoantibody secretion by peripheral lymphocytes.

A 59-year-old woman with systemic lupus erythematosus was found to have marked hyperglycemia, extreme insulin resistance and abnormally high plasma immunoreactive insulin. Her circulating erythrocytes displayed a dramatic decrease of 125I-labeled insulin binding. Both the whole serum and purified IgG fraction strongly inhibited the binding of radiolabeled insulin to control erythrocytes. These results suggested, although indirectly, the existence of antibodies to insulin receptors in the serum of the patient. To directly investigate this issue, we used an enzyme-linked solid-phase immunoassay which allows the detection and enumeration of lymphocytes secreting antibodies towards insulin receptors. Peroxidase-conjugated anti-human immunoglobulin is used to reveal the binding of antibodies to insulin receptor-coated dishes. We demonstrated that the patient's mononuclear cells, when briefly incubated in Petri dishes with partially purified insulin receptor, were able to secrete immunoglobulins of G class specifically directed to the antigen. Moreover, only a fraction of the whole population of anti-insulin receptor antibodies was directed towards the insulin binding region of the receptor, seemingly corresponding to the auto-antibodies detected with conventional binding-inhibition assay.

Remission from insulin dependence induced by continuous subcutaneous insulin infusion (CSII) in type I, newly diagnosed diabetics: role of some hormonal and immunologic factors.

Optimal and early control of recent onset, type I diabetes by intensive insulin therapy has been reported to allow insulin withdrawal in about two thirds of subjects treated. We used continuous s.c. insulin infusion (CSII) in the attempt to induce a temporary remission of insulin dependence in 18 newly diagnosed young adult diabetics. After 10 days of optimized glycometabolic control, insulin infusion was stopped and patients were switched to glibenclamide (15 mg/die) plus metformin (1 g/die). Diabetics were considered in remission of insulin dependence when their metabolic control fulfilled the following criteria for at least 3 months: absence of glycosuria, pre- and post-prandial blood glucose less than or equal to 120 and 180 mg/dl, respectively, HbA1c less than or equal to 7%. Insulin therapy could be discontinued for periods of over three months in 11 subjects (61%) and for as long as 18 months in one case. Insulin requirement during CSII was slightly higher in nonremitters (NR) than in remitters (R): 0.36-0.64 vs 0.26-0.41 U/kg/die. After 24 months from CSII, R still showed lower insulin requirement (0.35-0.42 U/kg/die) than NR (0.55-0.75 U/kg/die). Further, the role of some hormonal and immunologic factors was investigated. Plasma C-peptide and glucagon were measured, fasting and 2h after each meal, both on admission and immediately after CSII, when patients were switched to oral therapy. No difference in hormone levels could be detected on admission, whereas, after CSII, mean post-prandial increase of C-peptide over basal was significantly higher in R than in NR (1.18 +/- 0.37 vs 0.22 +/- 0.16 ng/ml, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of tsh binding inhibiting antibodies (TBI-ab) and thyroid adenylate cyclase stimulating antibodies (TS-ab) in sera of patients with Graves' disease.

In the sera of patients with Graves' disease have been demonstrated the immunoglobulins able to inhibit the binding of TSH to the human thyroid membrane (TBI-Ab) and the immunoglobulins stimulating the thyroid adenylate cyclase (TS-Ab). The present study was performed in 75 hyperthyroid Graves' patients to ascertain the pathophysiological significance of these immunoglobulins. TS-Ab and TBI-Ab prevalence appeared to be much higher in the untreated and in relapsing patients than in subjects in remission. When the results of TBI-Ab and TS-Ab were compared in each group of patients no correlation was found between the two activities. We conclude that the TBI-Ab and the TS-Ab are the markers of hyperthyroidism in Graves' disease but the two activities are not equivalent and probably reflect a different phenomenon concomitantly produced.

Changes in circulating iodothyronines in diabetics with various degrees of metabolic control.

Plasma TSH, total and free T3 and T4, reverse T3, blood pH, HbAlc, ketonuria and glycosuria were evaluated in 8 subjects with diabetic ketoacidosis, in 54 diabetics of group 1 and group 2 without severe metabolic derangement and in 10 control women. The diabetics with ketoacidosis showed before intensive therapy low T3, total and free, and high reverse T3 concentrations as compared to controls (unpaired t-test, p less than 0.001). After one day of intensive therapy the decrease of hyperglycemia and pH increase (p less than 0.001, paired t-test), glycosuria and ketonuria are not related to significant variations of iodothyronines and TSH. The significant variations (paired t-test, p less than 0.001) in total and free T3 and in reverse T3 concentrations were found only six days after remission of ketoacidosis. In diabetics (type 1 and 2) without recent history of ketoacidosis no differences were found in mean total and free T3 and T4, in reverse T3 and in plasma concentrations although mean blood glucose and HbAlc were statistically different (t-test, p less than 0.001). The changes in serum T3 (total and free) and reverse T3 are useful indicators of total metabolic control during the management of diabetic ketoacidosis.

[Sleep and the circadian rhythm of cortisol in transsexuals]. / Sonno e ritmo circadiano del cortisolo in transessuali.

Polygraphic recordings of nocturnal sleep and hormonal behavior were studied in three male and two female transexual subjects, aged 17 to 26 years, who had required a surgical sex reassignment. The transexual state was assayed by psychological investigations according to the law. All subjects appeared healthy at physical examination and no abnormalities were revealed by basal laboratory data. Chromosomal picture was in accordance with sexual characteristics. Pituitary sella enlargements were excluded by radiographic examination. In each patient two adjustment days were followed by polygraphic recording (EEG,EOG,EMG of chin muscles) of nocturnal sleep and blood drawing for cortisol assay. Blood samples were drawn at 30 minutes intervals for 24 hours, starting from the bedding-time. Hormonal blood concentration were determined by radioimmunoassay. Cosinor method was employed in the analysis of circadian rhythm. In transexual subjects the percentage of sleep intermediate phase, or ambiguous sleep, with reference to total sleep time, was significantly higher than in matched controls.(ABSTRACT TRUNCATED AT 250 WORDS)

[Chronobiological aspects of TSH secretion in control subjects and in subjects with primary hypothyroidism]. / Aspetti cronobiologici della secrezione del TSH in soggetti controllo e con ipotiroidismo primario.

The circadian rhythm in plasma TSH concentration was demonstrated in euthyroid subjects and in treated hypothyroid patients. Our results suggest that two hypothalamic areas, involved in TRH secretion, are responsables in basal as well impulsive pituitary TSH dismission.

[Various types of reducing diets]. / I vari tipi di diete dimagranti.

It must be readily understood that the only possibility of fighting obesity is by bringing about a reversal in the energy balance so that inputs are smaller than outputs. At least theoretically, then, obesity's special quality is that it does not present any therapeutic problem. Restriction in food intake is currently the treatment of choice; to be effective, food intake must be cut so that the energy provided is below the obese person's daily consumption, on average below 1200 calories per day, while at the same time holding a comparatively high intake of indispensable elements (proteins, vitamins, certain minerals and oligo-elements). The physician has a choice of various possibilities represented by fasting, a variety of free or controlled diets, protein diets or diets with low carbohydrate content and with a variable fat content; dissociated, zig-zag, one food diets etc. Substantially all these tend to limit the total quantity of glycides and boost the feeling of satiety by increasing the total volume of good while keeping total calories unvaried. It is clear that each of them has specific indications and clear-cut contraindications. The aim is to produce a calory shortfall, not cause denutrition. The diet must therefore be suited to the individual directed during subsequent stages of weight loss in relation to the patient's specific requirements (number of meals, etc.).