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Biomedical subjects

R Mota

Publications and source records attributed to R Mota.

8 recordsLinked to original sources
PubMed2006

VUV spectroscopy of water under cellular conditions.

The understanding of radiation damage within cells, and thence mutagenesis, depends upon a detailed knowledge of the spectroscopy and dissociation dynamics of water. Results of a new study of the electronic state spectroscopy of water, using synchrotron radiation are reported. In order to gain some insight into how the spectroscopy and dissociation dynamics of water is influenced by its environment we also report photo-absorption spectra of water within thin films of poly(o-methoxyaniline) which have been suggested as a good mimic for biological membranes in the cellular environment. Comparison of these spectra with those of gaseous water and condensed amorphous water ice suggest that water in such films is similar to gaseous water and does not show the blue shift suggested in some cellular models. The lowest energy of OH production from dissociation of water in the cellular environment may therefore be around 6.7 eV (185 nm).

Cell Membrane↗
PubMed2006

[Frequent and rare dermatological diseases in HIV patients].

HIV patients develop a variety of infectious and non-infectious diseases of the skin and mucous membranes. Some of these serve as indicator diseases for a weakening immune system. While none of the dermatological complications is pathognomonic, conditions such as oral hairy leukoplakia, herpes zoster, thrush, and eosinophilic folliculitis should make physicians consider the possibility of underlying HIV disease. Moreover, one has to consider HIV if these skin diseases take an atypical or severe course, or if they do not respond properly to appropriate medication. Frequent and rare dermatoses occurring in HIV infection are discussed.

AIDS-Related Opportunistic Infections↗
PubMed2006

Doppler ultrasonographic and scintigraphic assessment of an auxiliary heterotopic liver transplantation with portal vein arterialization in pigs.

OBJECTIVE: Our aim was to evaluate liver graft integrity and function using scintigraphy and ultrasonography in a porcine model of auxiliary heterotopic liver transplantation with portal vein arterialization (AHLT-PVA). MATERIALS AND METHODS: Using Doppler ultrasonography we evaluated eight AHLT-PVA by parenchymal echogenicity, portal and arterial anatomy, and portal and biliary system flow. Two types of scintigraphy were performed: microaggregated human albumin colloid scintigraphy and diisopropyl iminodiacetic acid (DISIDA) scintigraphy, both labeled with 99mTc. RESULTS: The animals were distributed into two groups. The first group consisted of three animals with clinical suspicion of graft dysfunction, in which the ultrasonographic study revealed areas of parenchymal destructuring. In the scintigraphic study, heterogenous uptake was observed; there was no uptake in one animal. Necropsy of these three animals revealed areas of graft necrosis. The second group consisted of five animals with good clinical evolutions, in which the ultrasonographic study showed portal dilation, portal flow with arterial spiculations, and homogenous echogenicity of the hepatic parenchyma. The scintigraphic study revealed homogenous uptake by the graft and an elimination speed of the hepatobiliary agent similar to that of the native liver. CONCLUSIONS: An heterogenous echostructure of the graft provided a sign of poor prognosis indicating necrosis in the same way as heterogenous uptake or nonuptake of radioisotope upon scintigraphy. Scintigraphy is a good method to evaluate biliary function and bile elimination. In an AHLT-PVA, the main ultrasound findings derived from arterialization were dilation of the portal system and portal flow with arterial spiculations.

Animals↗
PubMed2005

Vacancy formation process in carbon nanotubes: first-principles approach.

The electronic and structural properties of a single-walled carbon nanotube (SWNT) under mechanical deformation are studied using first-principles calculations based on the density functional theory. A force is applied over one particular C-atom with enough strength to break the chemical bonds between the atom and its nearest neighbors, leading to a final configuration represented by one tube with a vacancy and an isolated C-atom inside the tube. Our investigation demonstrates that there is a tendency that the first bond to break is the one most parallel possible to the tube axis and, after, the remaining two other bonds are broken. The analysis of the electronic charge densities, just before and after the bonds breaking, helps to elucidate how the vacancy is formed on an atom-by-atom basis. In particular, for tubes with a diameter around 11 angstroms, it is shown that the chemical bonds start to break only when the externally applied force is of the order of 14 nN and it is independent of the chirality. The formation energies for the vacancies created using this process are almost independent of the chirality, otherwise the bonds broken and the reconstruction are dependent.

Journal Article↗
PubMed1993

[Immunoproliferative disease of the small intestine. Report of a case].

We report one case of immunoproliferative small intestinal disease with two rare characteristics. Firstly, the detection of monoclonal IgA-Kappa in serum and in the intestinal infiltrate and secondly, the advanced age of the patient at diagnosis. We checked up on Spanish literature and found an important number of patients that were diagnosed at such an age. We suggest that this disease may appear in elderly people in developed countries.

Aged↗
PubMedDate not supplied

[Human papillomavirus associated with uterine cervix lesions].

It was studied the prevalence of human papillomavirus (HPV) among 228 women with lesions of uterine cervix attending the Ofir Loiola Institute, in Belem, Para, from March 1992 to May 1996. Histopathological examination was performed with all cervical biopsy samples obtained from these patients. In addition, specimens were analysed by both polimerase chain reaction and dot-blot hybridization to detect HPV DNA. The patients were assigned to three groups, according to the diagnosis made by histopathology, as follows: A, including 155 women suffering from invasive epidermoid carcinoma or adenocarcinoma; B, 54 patients having either cervical intraepithelial neoplasia grade II or III; and C, involving 19 women with chronic cervicitis. The prevalence rates of HPV in groups A, B and C were 70.3%, 63% and 36.8% respectively. HPV 16 accounted for 60.4% and 54.5% of types identified in groups A and B, respectively. Altogether HPV types 16, 18 and 33 were detected in 71.4% of positive patients belonging to group C.

Biopsy↗