Digestive symptoms in young individuals: survey among medical students]

The purpose of this study was to assess the frequency patterns of 8 digestive symptoms and related features, with regard to functional disorders, in young adults. A sample of 279 subjects, representing the student body at the Medical School of Brasília, filled up the self-report questionnaire. From 20% to 27% of subjects reported more than 6 episodes of one more of the following symptoms, within a 12-month period: indigestion, distension, constipation, heartburn, abdominal pain, and diarrhea. A higher prevalence of constipation in women was a significant (p < 0.05) difference between the sexes. Dyspepsia and irritable bowel syndrome (IBS) were identified by clinical criteria in 25% and 9% of subjects, respectively, while 4% disclosed the occurrence of an organic disease. About 30% of the subjects volunteered perceptions on the meaning of the symptoms, while 22% reported days of restricted activities ascribed to the symptoms. Days of restricted activities were significantly (p < 0.05) related to the number, the type (diarrhea, nausea and vomiting, and abdominal pain), and the IBS pattern of symptoms (but not to the dyspepsia pattern). In conclusion, a substantial proportion of subjects in this student group, contacted at the workplace, showed indexes of clinical dysfunction (recurrence of multiple symptoms), and of social dysfunction (days of restricted activity), which indicate persistent limitations on the digestive health status.     

Changes in Neuropsychological Functioning with Progression of HIV-1 Infection: Results of an 8-Year Longitudinal Investigation

Despite the advent of more effective treatments for HIV-1 infection, cognitive impairment is still frequent and questions remain regarding which areas of impairment are more common in the different disease stages. This study investigated cognitive performance over an 8-year period of time in 59 HIV-1 seropositive (HIV-1+) men who were clinically asymptomatic at study entry, in comparison to a cohort of 55 HIV-1 seronegative (HIV-1-) men. Every 6 months we examined cognitive functioning in 5 domains-fine motor speed, attention, verbal memory, executive functioning, and speed of information processing. We found that patients with AIDS scored significantly worse on fine motor speed and speed of information processing than HIV-1- individuals and the HIV-1+ non-AIDS patients. In addition, the HIV-1+ non-AIDS patients performed more poorly than the HIV-1- group on speed of information processing. Depressive symptoms were also associated with diminished performance on measures of attention, executive functioning, and speed of information processing. Further research is needed to examine the effects of disease stage and depression on cognitive impairment in the era of new HIV treatments.     

Contribution to the surgical treatment of patients with cervical spine cord injury using simple procedures

Thirty-nine patients with acute cervical spine fractures and/or dislocations between C3 and C7 were submitted to an anterior approach using bone graft fixation without screw and plate systems and three required a preliminary posterior approach to reduce a dislocation. Graft dislodgement due to technical problems occurred at a rate of 7.7% postoperatively and 2.8% 1 month later. No redislodgement occurred. All fusions became solid after 3 months. Their progress was based on the Frankel scale, before surgery, at the moment of the discharge, and at 6 months follow-up. This experience shows how patients with an acute cervical injury can improve even when admitted late after trauma.     

Prevention of Mother-to-Child Transmission of HIV: Compliance with the Recommendations of the Brazilian National STD/AIDS Control Program for Prenatal and Perinatal HIV Testing in Porto Alegre, Brazil

In order to benefit from antiretroviral therapy, pregnant women infected with HIV must be tested and diagnosed. Not infrequently, however, women present in labor without prior prenatal care and are thus unable to benefit fully from HIV testing and, if infected, antiretroviral therapy. In this study we evaluated the need for rapid perinatal HIV testing for untested mothers presenting in labor in a public maternal–child hospital that provides care for metropolitan Porto Alegre, Brazil, and potentially modifiable risk factors for noncompliance with national recommendations. We surveyed a consecutive sample of women who gave birth at Hospital Materno–Infantil Presidente Vargas (Presidente Vargas Mother-and-child Hospital) in August–October 2001and administered a structured questionnaire to consenting participants. The questionnaire consisted of demographic data, information on health-seeking behavior, knowledge of HIV infection, and testing during pregnancy. We confirmed information on HIV testing, syphilis, and hepatitis B by examination of the patient's prenatal records. We also obtained data regarding laboratory testing and treatment during labor and delivery (e.g., HIV testing, antiretroviral treatment, and suppression of lactation) from hospital inpatient charts. Of 214 eligible participants, 209 (98%) agreed to participate in the study. Overall 173 (83%) of the 209 participants had had a previous HIV test and 36 (17%) had not. Women with fewer pregnancies were more likely to have been tested (p = .017), as were women with lower family incomes (p = .007). No women had received rapid tests in the delivery room. Of the 209 participants, 201 (96%) had had at least one prenatal visit and 169 (81%) had had three or more visits; 12 (6%) of these reported that they had not been offered an HIV test, 5 (2%) did not know if testing had been offered or not, and 191 (95%) reported that they had been offered a test. We were able to obtain prenatal records for 190 (95%) of the 201participants who had received prenatal care. HIV testing was not mentioned in 9% of charts. Results of syphilis tests were recorded on prenatal records or hospital charts for 167 (80%)participants, and results of hepatitis B surface antigen were found for 93 (45%). Women who to 30pchad had three or more prenatal visits were significantly more likely to have been tested for to 30pcHIV (OR 46.96, 95% CI, 15.92–144.85, .0001), syphilis (OR 31.64, 95% CI, 11.81–87.42, p < .0001) or HBsAg (OR, 4.88, 95% CI, 1.91–12.99, p < .0001) than women who had had two prenatal visits or fewer. Our study showed shown that in 12% of the pregnancies included in our sample national recommendations for prenatal or perinatal testing were not followed, and in an additional 5%, HIV testing, though offered, was not obtained. These women could potentially have benefited from rapid HIV testing. As knowledge of HIV and risk factors for transmission were almost universal in our sample, we believe that the passive health-seeking behavior we observed may offer an opportunity for targeting new efforts to promote the importance of prenatal care and prenatal diagnosis of HIV.     

Sweet's syndrome and intestinal inflammatory disease. A case report and review of the literature

Sweet's syndrome, or febrile neutrophilic dermatosis, is a process characterized by fever, red tender plaques, neutrophilia and neutrophilic dermal infiltrate with papilar edema in the absence of vasculitis. The association with intestinal inflammatory disease is inusual, a new case associated with ulcerative colitis is reported, and we perform a literature review of Sweet's associated intestinal inflammatory disease.     

ATP diphosphohydrolase in human platelets from patients with coronary arteries heart disease

ATP diphosphohydrolase is an enzyme described in platelets and may be related to the control of ADP-dependent platelet aggregation. Platelet aggregation in atherosclerotic coronary arteries, and the release of platelet-derived factors, play an important role in coronary artery disease syndromes. In this study, we determined the activity of ATP diphosphohydrolase in platelets from patients with chronic and acute coronary artery disease syndromes and healthy persons. The following groups were studied: healthy persons (group I), patients with chronic heart disease (group II) and acute heart disease (group III). Results did not demonstrate differences between the groups studied. The control group demonstrated a lower range of enzyme activity. The patients from groups II and III had ingested drugs with actions upon the cardiovascular system and the effect, in vitro, of these drugs upon the ATP diphosphohydrolase activity in human platelets was also investigated. The in vitro experiments demonstrated that 2.0 mM acetylsalicylic acid inhibited ATP hydrolysis by human platelets by approximately 55%. Significant correlation was observed between ADP hydrolysis and glucose blood levels in the control group and between ATP hydrolysis and triglycerides in the group II. These results contribute to our understanding of a possible relationship between ATP diphosphohydrolase and thrombogenesis.     

Vaccines, viruses, and voodoo.

Vaccinations are invaluable in protection from a wide variety of diseases that can cause substantial morbidity and mortality. Although a rare complication of vaccination, autoimmune disorders represent one of these morbidities. Recently, widespread public concern has arisen from case reports suggesting that--similar to what has been observed after natural viral infections--there might be an association between specific immunizations and autoimmune diseases. Herein we address the biological plausibility of such a connection, focusing particularly on the examples of hepatitis B, rubella, and measles-mumps-rubella (MMR) vaccinations, and the autoimmune diseases they are potentially associated with. Our review of the available data suggests that, for the general population, the risk: benefit ratio is overwhelmingly in favor of vaccinations. However, the possibility cannot be ruled out that, in genetically susceptible individuals, vaccination can result in the unmasking of an autoimmune disease triggered by the immunization. We also critically examine the existing data suggesting a link between immunization against MMR and autism, and briefly discuss the controversial evidence pointing to a possible relationship between mercury exposure from vaccines and autistic disorders. There is a continued urgent need for rigorously designed and executed studies addressing these potential associations, although the use of vaccinations remains a critical public health tool for protection against infectious disease.     

Biological evaluation of intervertebral disc cells in different formulations of gellan gum‐based hydrogels

Gellan gum (GG)‐based hydrogels are advantageous in tissue engineering not only due to their ability to retain large quantities of water and provide a similar environment to that of natural extracellular matrix (ECM), but also because they can gelify in situ in seconds. Their mechanical properties can be fine‐tuned to mimic natural tissues such as the nucleus pulposus (NP). This study produced different formulations of GG hydrogels by mixing varying amounts of methacrylated (GG‐MA) and high‐acyl gellan gums (HA‐GG) for applications as acellular and cellular NP substitutes. The hydrogels were physicochemically characterized by dynamic mechanical analysis. Degradation and swelling abilities were assessed by soaking in a phosphate buffered saline solution for up to 170 h. Results showed that as HA‐GG content increased, the modulus of the hydrogels decreased. Moreover, increases in HA‐GG content induced greater weight loss in the GG‐MA/HA‐GG formulation compared to GG‐MA hydrogel. Potential cytotoxicity of the hydrogel was assessed by culturing rabbit NP cells up to 7 days. An MTS assay was performed by seeding rabbit NP cells onto the surface of 3D hydrogel disc formulations. Viability of rabbit NP cells encapsulated within the different hydrogel formulations was also evaluated by Calcein‐AM and ATP assays. Results showed that tunable GG‐MA/HA‐GG hydrogels were non‐cytotoxic and supported viability of rabbit NP cells. Copyright © 2012 John Wiley & Sons, Ltd.     

Giant exciton-enhanced shift currents and direct current conduction with subbandgap photo excitations produced by many-electron interactions

Shift current is a direct current generated from nonlinear light–matter interaction in a noncentrosymmetric crystal and is considered a promising candidate for next-generation photovoltaic devices. The mechanism for shift currents in real materials is, however, still not well understood, especially if electron–hole interactions are included. Here, we employ a first-principles interacting Green’s-function approach on the Keldysh contour with real-time propagation to study photocurrents generated by nonlinear optical processes under continuous wave illumination in real materials. We demonstrate a strong direct current shift current at subbandgap excitation frequencies in monolayer GeS due to strongly bound excitons, as well as a giant excitonic enhancement in the shift current coefficients at above bandgap photon frequencies. Our results suggest that atomically thin two-dimensional materials may be promising building blocks for next-generation shift current devices.

When continuous wave light is shone on a noncentrosymmetric crystal, a direct current (DC) can arise due to a second-order optical response of the crystal. The origin of this current is interpreted to be related to the “shift” (1–4) of the intracell coordinates of the excited electron. This so-called shift current is proposed as an alternative to the photocurrent generated by traditional semiconductor p–n junctions (i.e., a junction between hole-doped [p-type] and electron-doped [n-type] semiconductors) for photovoltaic applications (5, 6). Unlike conventional photovoltaic devices, shift current is a bulk phenomenon, which does not require a p–n junction to separate the optically generated electron–hole pair for a DC. Moreover, recent studies reveal that the photocarriers in shift current can have long travel distances, which is distinct from the usual drift transport mechanism in traditional solar cells (7, 8) and makes shift current a promising candidate for efficient energy conversion.Despite many investigations over the past decade, a basic understanding of shift currents is far from complete. Most theoretical studies to date rely on the assumption of having noninteracting particles (3–6, 9–11). Given that it is well known that light-induced electron–hole pairs can form bound or resonant excitons (correlated electron–hole states), which dominate and qualitatively change the absorption features of semiconductors, electron–hole interactions or excitons are expected to play a large role in shift currents, especially for reduced dimensional systems. However, it is not straight forward to generalize existing ab initio methods [such as the ab initio GW plus Bethe-Salpeter equation (GW-BSE) approach (12)], used to understand and compute excitonic effects in linear optical absorption, to study nonlinear optical responses. Different model approaches to investigate the effects of many-electron interactions on nonlinear optical responses of materials have been proposed. For instance, a Floquet-based model Hamiltonian formalism showed that excitonic effects enhance nonlinear response (13). In the specific case of second harmonic generation, first-principles approaches have been developed and applied to real materials, for instance, by making an approximation to the full many-body perturbation theory treatment (14, 15) or to the time-dependent density function theory, in which electron interaction effects are taken into account via simplified kernels (16). A real-time formulation based on propagating the time-dependent Schrodinger equation has also been developed (17) and applied to second harmonic generation (18). For shift currents in real materials, only one recent study considered the effects of excitons on the linear optical coefficient that might influence shift currents, but these authors included only the effects of excitons on the electromagnetic field profile in a bulk sample, and the crucial process of shift current generation itself is still treated within an independent-particle picture (11). Thus, there is still no first-principles calculation and understanding of the role of many-electron interactions, particularly those due to excitons, on shift currents.Here, we show from first principles that 1) bound exciton states in the band gap can generate substantial shift currents, and 2) excitonic effects in the electron–hole continuum part of the spectrum can also greatly enhance shift currents due to the enhancement of the optical matrix elements from the coherence of the electron–hole pairs and to interexciton couplings that arose in the nonlinear responses.