Metal oxalates in paints: a Raman investigation on the relative reactivities of different pigments to oxalic acid solutions.

One degradation phenomenon that occurs in artworks is the formation of metal oxalates on their surfaces. In order to gain insight into the inclination of pigments to produce oxalates, nine pigments including Na, Ca, Fe, Pb and Cu cations were selected to react with oxalic acid solutions at different concentrations (1 M, 0.1 M, 0.01 M and 0.005 M). Micro-Raman spectroscopy was used to detect the different reaction products. Pigments containing calcium (calcite, gypsum and Volterra gypsum) showed a high tendency to form weddellite as well as whewellite, especially at high acidic concentrations; among copper-based pigments (malachite, azurite, verdigris), the formation of moolooite was observed for high concentrations of acid and down to the lowest concentration (0.005 M) in the case of verdigris. Lead oxalate was detected on lead white. No iron oxalates were observed for hematite; the formation of calcium oxalate crystals was observed instead. Ultramarine blue reacted to produce elemental sulfur. According to the results obtained, calcite and verdigris showed the highest reactivity in oxalic acid environments, resulting in a high tendency to form calcium and copper oxalates, even at very low acidic concentrations; this behavior seems to arise from the high solubilities of these pigments in acidic environments.

A new compact instrument for Raman, laser-induced breakdown, and laser-induced fluorescence spectroscopy of works of art and their constituent materials.

A small, potentially transportable prototype instrument capable of carrying out Raman, laser-induced breakdown (LIB), and laser-induced fluorescence (LIF) spectroscopy using a single pulsed laser source was developed for the analysis of cultural heritage objects. The purpose of this instrumentation is to perform fast and reliable analysis of surfaces with minimum damage to an object. For this purpose, a compact (51 x 203 x 76 mm) nanosecond Q-switched neodymium doped yttrium aluminum garnet laser (8 ns, 20 Hz, 0.01-115 mJ/pulse) was used as an irradiation source. The use of a nanosecond-gated detector sensitive between 180 and 900 nm allows the acquisition of elemental emissions in LIB spectroscopy and can also be employed for both LIF and time-resolved Raman spectroscopy. In this work, attention is focused on the description of the instrument and its optical components, and two examples of applications for the analysis of pigments and binding media used in works of art are presented.

Spectroscopic analysis of works of art using a single LIBS and pulsed Raman setup.

A nanosecond pulsed laser setup has been optimized to perform laser-induced breakdown spectroscopy (LIBS) and pulsed Raman spectroscopy measurements in the field of cultural heritage. Three different samples of artistic/architectural interest with different typologies have been analyzed. The results from the two techniques allowed the identification of the materials used in their manufacture or contaminating them, probably coming from atmospheric pollution and biological activity. No sampling and sample preparation was required before the measurements, and no visual or structural damage was observed. Depth profiling using LIBS was performed in one of the samples, providing elemental information along the different layers composing the object and covering its surface. The quality of the results and the rather short time needed for the measurements and for switching between techniques confirmed the instrument's capabilities and specificity for dealing with objects of artistic or historical interest.

Analysis of natural and artificial ultramarine blue pigments using laser induced breakdown and pulsed Raman spectroscopy, statistical analysis and light microscopy.

Pulsed laser induced breakdown spectroscopy (LIBS) and Raman spectroscopy were performed using a novel laboratory setup employing the same Nd:YAG laser emission at 532 nm for the analysis of five commercially available pigments collectively known as "ultramarine blue", a sodium silicate material of either mineral origin or an artificially produced glass. LIBS and Raman spectroscopy have provided information regarding the elemental and molecular composition of the samples; additionally, an analytical protocol for the differentiation between natural (lapis lazuli) and artificial ultramarine blue pigments is proposed. In particular LIBS analysis has allowed the discrimination between pigments on the basis of peaks ascribed to calcium. The presence of calcite in the natural blue pigments has been confirmed following Raman spectroscopy in specific areas of the samples, and micro-Raman and optical microscopy have further corroborated the presence of calcite inclusions in the samples of natural origin. Finally multivariate analysis of Laser induced breakdown spectra using principal component analysis (PCA) further enhanced the differentiation between natural and artificial ultramarine blue pigments.

Influence of cholecalciferol (vitamin D3) on the course of experimental systemic lupus erythematosus in F1 (NZBxW) mice.

The course of systemic lupus erythematosus (SLE), an autoimmune disease, is markedly affected by hormones such as estrogen and prolactin. It is well known that heavy exposure to sunlight has deleterious effects on SLE, triggering episodes of the disease. Classical explanations for this occurrence suggest that UV radiation damages DNA, which becomes immunogenic, or induces exposure of the Ro antigen in keratinocytes. In recent years, it has been shown that vitamin D3 has important effects on the immune system. Thus, we proposed an alternative hypothesis, suggesting that UV radiation, by promoting vitamin D3 synthesis, could be a factor aggravating the course of SLE after exposure to sunlight. To test this hypothesis, we injected F1(NZBxW) mice, which are prone to developing SLE, with vitamin D3, and we demonstrated a worsening of the histopathological findings in the kidney.

Endolymphatic irradiation in preparation for renal transplantation: a 26-year's follow-up.

OBJECTIVE: The aim of the present study was to analyze the long-term evolution of patients submitted to endolymphatic irradiation as a pre-transplant preparation. SETTING: Referral center of university hospital. DESIGN: Case-control study. MAIN OUTCOMES MEASURES: The study was designed to evaluate the incidence of rejection, kidney loss, leukopenia, infection, and graft survival in the group treated (group 1) prior to surgery, compared to a control group (group 2) composed of patients under identical clinical conditions (sex, age, type of donor, immunosuppressive therapy and time of transplant) that did not undergo treatment preparation. PATIENTS: Patients were selected from amongst transplantation candidates on a long-term waiting list, some with a high level of antibodies against panel. The control group was chosen from amongst recently transplanted patients. Patients in the treated group received lipoiodine containing 131I with specific activity ranging between 4 and 6 mCu/ml. RESULTS: A significant difference between the two groups was found with regard to the incidence of rejection crises (21.0% in group 1 and 73.6% in group 2; P = 0.003), and the maintenance dose of azathioprine (smaller in group 1; P < 0.01). As to kidney graft loss due to rejection, a tendency to significance could be identified (10.5% in group 1 and 42.1% in group 2; P = 0.063); however, the difference was not significant between the two groups in terms of reversibility of rejection episodes during the first 60 post-transplant days. CONCLUSIONS: The authors concluded that this method, besides being relatively innocuous (there was no compromising of either the thyroid gland or of gonad function and there was no increase in tumor incidence), has an extended immunosuppressive effect, and can be indicated for cadaveric renal allograft recipients, especially those showing high panel reactivity.

Stored blood--an effective immunosuppressive method for transplantation of kidneys from unrelated donors. An 11-year follow-up.

Thirty-seven patients were submitted to kidney transplantation after transfusion at 2-week intervals with 4-week stored blood from their potential donors. All patients and donors were typed for HLA-A-B and DR antigens. The patients were also tested for cytotoxic antibodies against donor antigens before each transfusion. The percentage of panel reactive antibodies (PRA) was determined against a selected panel of 30 cell donors before and after the transfusions. The patients were immunosuppressed with azathioprine and prednisone. Rejection crises were treated with methylprednisolone. The control group consisted of 23 patients who received grafts from an unrelated donor but who did not receive donor-specific pretransplant blood transfusion. The incidence and reversibility of rejection episodes, allograft loss caused by rejection, and patient and graft survival rates were determined for both groups. Non-parametric methods (chi-square and Fisher tests) were used for statistical analysis, with the level of significance set at P < 0.05. The incidence and reversibility of rejection crises during the first 60 post-transplant days did not differ significantly between groups. The actuarial graft and patient survival rates at five years were 56% and 77%, respectively, for the treated group and 39.8% and 57.5% for the control group. Graft loss due to rejection was significantly higher in the untreated group (P = 0.0026) which also required more intense immunosuppression (P = 0.0001). We conclude that transfusions using stored blood have the immunosuppressive effect of fresh blood transfusions without the risk of provoking a widespread formation of antibodies. In addition, this method permits a reduction of the immunosuppressive drugs during the process without impairing the adequate functioning of the renal graft.

Stored blood - an effective immunosuppressive method from unrelated donors: an 11-year follow-up

Thirty-seven patients were submitted to kidney trasnplantation after transfusion at 2-weeck intervals with 4-week stored blood from their potential donors. All patients and donors were typed for HLA-A-B and DR antigens. The patients were also tested for cytotoxic antibodies against donor antigens before each transfusion. The percentage of penel reactive antibodies (PRA) reative antibodies (PRA) was determined against a selected panel of 30 cell donors before and after the transfusions. The patients were immunosuppressed with azathioprine and prednisone. Rejection crises were treated with methylprednisolone. The control group consisted of 23 patients who received grafts from an unrelated donor but who did not receive donor-specific pretransplant blood transfusion. The incidence and reversibility of rejection episodes, allograft loss caused by rejection, and patient and graft survival rates were determined for both groups. Non-parametric methods (chi-square and Fisher tests) were used for statistical analysis, with the level of significance set at P<0.05. The incidence and reversibility of rejection crises during the first 60 post-transplant days did not differ significantly between groups. The actuarial graft and patient survival rates at five years were 56 percent and 77 percent, respectively, for the treated group and 39,8 percent and 57.5 percent for the control group. Graft loss due to rejection was significantly higher in the untreated group (P = 0.0026) which also required more intense immunosuppression (P = 0.0001). We conclude that tranfusions using stored blood have the immunosuppressive effect of fresh blood transfusions without the risk of provoking a widespread formation of antibodies. In addition, this method permits a reduction of the immunosuppressive drugs during the process with-out impairing the adequate funsctioning of the renal graft.

Quantitation of soluble E-receptor of T lymphocytes in serum from HIV-1 positive patients.

Human T lymphocytes carry a membrane receptor for sheep erythrocytes (E) related to the CD2 molecule. The E-receptor is found in a soluble from (Rs) in serum and can be quantitated by "rocket electrophoresis" using an anti-Rs serum obtained by immunizing sheep with autologous erythrocytes coated with Rs. Increased serum levels of Rs are found in patients with diseases associated with immunodepression. In the present study, 14 asymptomatic HIV-1 seropositive individuals were investigated regarding their Rs levels and delayed hypersensitivity skin tests every 3 months for a period of 35 months. All these patients progressed to AIDS in this period. Rs serum levels have also been quantitated in 14 normal individuals. The mean Rs values in normal individuals, asymptomatic, and AIDS patients were, respectively: 4.8 +/- 1.5 mm (SD), 9.6 +/- 1.9 mm (SD) and 11.3 +/- 2.4 mm (SD). An increase of Rs serum levels was observed when we compared normal individuals with CDC-II and CDC-IV clinical stage patients (P < 0.05, Mann-Whitney test) and CDC-II and CDC-IV patients, (P < 0.05, Wilcoxon test). We have observed a depressed delayed hypersensitivity response to ubiquitous antigens in CDC-IV patients. Our results indicate that Rs serum levels can be used as a progression marker in HIV infected patients.

Effect of glucan on murine lupus evolution and on host resistance to Klebsiella pneumoniae.

Glucan is a polysaccharide from the yeast Saccharomyces cerevisiae that stimulates the mononuclear phagocytic system (MPS). NZB/NZW F1 mice were divided into two groups: one group received a subcutaneous injection of 0.5 mg glucan/animal for 1 week, and the other received the same dose for 3 months. No changes were observed in those animals submitted to short-term glucan treatment, whereas animals with active lupus and submitted to long-term glucan administration presented early death, with significant differences in accumulated mortality rates over 33-37 weeks, when compared to controls. No deaths were observed in lupus mice treated with glucan 24 hours before the induction of septic shock by Klebsiella pneumoniae, in contrast to mortality of 95.3% in the control group during the follow-up period of 12 days. We conclude that although glucan is able to exacerbate lupus activity, it enhances resistance to infection in lupus mice.

Evaluation of recent techniques for detection of red blood cell antibodies in sera of reference samples, patients, pregnant women, and blood donors.

The sensitivity of the low ionic strength solution antiglobulin test (LISS-AGT), polyethylene glycol antiglobulin test (PEG-AGT), low ionic strength solution solid-phase antiglobulin test (LISS-SPAT), gel low ionic strength solution antiglobulin test (GEL-LISS), and gel papain test (GEL-PAP) was compared in titration studies of 460 sera containing identified IgG alloantibodies. The GEL-PAP was 100% sensitive to detect Rh antibodies, whereas the PEG-AGT was the most sensitive to detect Kell, Duffy, Kidd, Ss, and rare blood group antibodies. The better performance of PEG-AGT was especially obvious with Kell, Duffy, and Ss antibodies (S = 100%). When the sensitivity of the LISS-AGT, PEG-AGT, GEL-LISS, and GEL-PAP was evaluated in different routines, the GEL-LISS showed to be more sensitive than PEG-AGT in the detection of clinically significant antibodies. These discrepant results showed that the performance of a technique may change when it is applied as a routine.

Cutaneous immediate and late phase reactions to schistosomin in schistosomiasis patients.

Cutaneous immediate and late phase reactions (LPR) to schistosomin were studied in 29 patients with schistosomiasis mansoni. In 12 of these patients, the determination of total and specific serum IgE by immunoenzymatic method against schistosome antigen was carried out using serum samples obtained on the same day as the cutaneous tests. Skin biopsies were taken from 4 typical LPRs. Immediate reactions occurred in all except one and LPRs in 12 (41.3%). Patients with positive cutaneous reactions had highe levels of specific serum IgE against schistosome antigen. Histopathological studies showed a moderate exudate consisting mainly of neutrophils (60%) and eosinophils (40%). LPRs in schistosomiasis have the same characteristics reported in the medical literature in relation to time of appearance, morphology and histopathology. The immunopathogenic role played by LPRs in the patients remains to be clarified.

HLA antigens and resistance to HIV.

The role of histocompatibility antigens in HIV infection has been investigated by several approaches. Thus the haplotype A1B8DR3 that is usually linked to autoimmune disorders seems to be associated with accelerated progression to AIDS. Cross-reactivity between MHC antigens and HIV-1 proteins is evident from alloimmunization experiments in mice and xenoimmunization of monkeys with human cells. Furthermore, recent reports suggest that some individuals with uncommon HLA antigens may be resistant to HIV infection. In addition to expressing cross-reacting antigens with HLA, HIV also exhibits substantial amounts of host beta-2 microglobulin and HLA-DR attached to its surface. Taken together, these data are stimulating new hypotheses relevant for AIDS pathogenesis. Based on alloimmunization, novel approaches have also been proposed in attempts to promote an effective immune response to HIV.

Infection prevention in patients with severe multiple trauma with the immunomodulator beta 1-3 polyglucose (glucan).

In a effect to prevent nosocomial pneumonia and sepsis, we treated patients with severe multiple trauma with an immunomodulator--beta 1-3 polyglucose (glucan). Forty-one patients with no infection at admission were stratified using Trauma Score and included in a randomized double-blind controlled trial. They were divided into a control group (n = 20) and a glucan group (n = 21). Pneumonia occurred in 11 of 20 patients in the control group and in two of 21 recipients of glucan (p < 0.01). Sepsis occurred in seven of 20 patients in the control group and in two of 21 patients treated with glucan (p < 0.05). Considering patients with pneumonia and sepsis, a decrease was observed in nosocomial infection from 65.0 to 14.4 percent (p < 0.001). The mortality rate related to infection was 30.0 percent in patients in the control group and 4.8 percent in the group treated with glucan (p < 0.05). The general mortality rate, cerebral deaths excluded, was 42.1 percent in the control group and 23.5 percent in the glucan group.

Immunomodulatory effect of glucan on the response to experimental antirabies vaccination.

The objective of the present study was to determine the stimulatory response to antirabies vaccination promoted by glucan in mice. Glucan increased both resistance to infection and antibody titres and this effect was more evident when glucan was used at dose of 0.5 mg, administered intraperitoneally before, during and after immunization and when the challenge virus was applied to the foot-pad.

Delayed hypersensitivity skin tests in prognosis of human immunodeficiency virus infection.

Delayed hypersensitivity skin tests (DHST) with recall antigens were investigated as prognostic markers in five different approaches. In the first study, 42 acquired immunodeficiency syndrome (AIDS) patients (IVb, IVcl, IVd, and IVe; MMWR 35:334-339, 1986) 26 AIDS-related complex (ARC) patients (IVa and IVc2), and 98 asymptomatic patients (II and III) were evaluated with candidin, tricophytin, PPD and streptokinase-streptodornase. In the second study, 10 patients (II and III) were evaluated sequentially with the same antigens. In the third, 45 patients with at least two positive skin tests ("reactors") were followed for one year and evaluated every 6 months with the same antigens. In the fourth, 16 "reactors" were followed and evaluated every 3 months with the same antigens. We measured the interval from the time at which patients first presented with only one or no positive DHST until the development of ARC or AIDS. In the last study, the correlation between absolute number of CD4+ lymphocytes and the number of DHST was studied in 151 patients. We found that the decrease in reactiveness to DHST correlated directly with the progression to AIDS, demonstrating the usefulness of this simple procedure as a valid prognostic marker.