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J C Araujo

Publications and source records attributed to J C Araujo.

15 recordsLinked to original sources
PubMed2004

Development and analysis of anaerobic biofilms onto hydrophobic and hydrophilic surfaces.

Fluorescent in situ hybridization (FISH) with domain and group specific probes that target intracellular 16S rRNA were used to investigate microbial composition of anaerobic biofilms developed on polypropylene (hydrophobic) and glass (hydrophilic) surfaces fitted inside a Modified Robbins Device (MRD). Crushed anaerobic granular sludge was used as inoculum for biofilm development in the MRD. The inoculum and biofilms formed showed nearly the same microbial composition, both were dominated by hydrogenotrophic methanogenic Archaea related to the Methanobacteriaceae as detected by the specific probe (MB1174). This group accounted for 44 to 90% of the DAPI-stained cells. Cells which hybridized to the Bacteria specific probe (EUB338) accounted for 3-18% of the DAPI-stained cells. After the first day of the biofilm formation experiment, a larger number of cells, 4.6 x 10(4) cells mm-2, could be seen colonizing the polypropylene coupon compared to the glass, 8.2 x 10(3) cells mm-2. However, after 9 days these numbers were very similar, i.e. 6.3 x 10(5) cells mm-2 and 7.2 x 10(5) cells mm-2, for the glass and polypropylene coupons, respectively. Our data suggest that the hydrophobicity of the support material did not influence the initial development and the microbial composition of anaerobic biofilms developed in the MRD.

Bacteria, Anaerobic↗
PubMed2003

Microbial community evaluation of anaerobic granular sludge from a hybrid reactor treating pentachlorophenol by using fluorescence in situ hybridization.

We used in situ hybridization with fluorescently labeled rRNA-targeted oligonucleotide probes concurrently with microscopic examinations and methane measurements to characterize the microbial community of an anaerobic hybrid reactor treating pentachlorophenol (PCP) with a mixture of fatty acids (propionic, butyric, acetic and lactic) and methanol. Archaeal cells detected with probe ARC915 prevailed in anaerobic granular sludge without and with the addition of PCP in a range of 2.0 to 21.0 mg/L to the reactor. This group accounted for 81 and 90% of the DAPI-stained cells before and after the addition of 21 mg/L of PCP, respectively. In these conditions, cells detected with the Methanosarcinales specific probe (MSMX860) were the only methanogenic Archaea found and accounted for 59 to 87.6% of the DAPI-stained cells. No cells were detected by the Methanomicrobiales (MG1200), Methanobacteriaceae (MB1174) and Methanococcaceae (MC1109) specific probes. Bacterial cells detected with probe EUB338 were found in very low numbers, which ranged from 5.7 to 1.0% of the DAPI-stained cells. This finding agrees with the scanning electron microscope examinations, in which cells morphologically resembling Methanosaeta and Methanosarcina were predominantly observed in the granular sludge. Results contributed to the investigation of the importance of the methanogens during PCP degradation.

Biomass↗
PubMed2002

Evaluation of thermophilic anaerobic microbial consortia using fluorescence in situ hybridization (FISH).

In this study we investigated the development of anaerobic biofilms in differential reactors and suspension cultures in batch reactors under thermophilic (55 degrees C) conditions. FISH, SEM, chemical and chromatographic analysis were used. The differential reactors reached 99.6%, 92.3% and 6.7% of acetic acid, COD and sulfate removal efficiencies, respectively, after 166 h of incubation time. The batch reactor reached 95.6% and 31.8% of acetic acid and sulfate removal efficiencies after 675 h, respectively. FISH results showed that bacterial cells rather than archaeal cells dominated biofilms. These cells, detected with the Bacteria specific probe (EUB338), accounted for 61.1% (+/-3.6) of the DAPI-stained cells and resembled acetate-oxidizing rods and Desulfotomaculum morphologies. Archaeal cells, which hybridized to the Archaea specific probe (ARC915), were also detected in biofilm but they accounted for 36.7% (+/-2.9) of the DAPI-stained cells. These cells were similar to Methanosaeta-like and hydrogenotrophic methanogen rods. In the suspension culture, archaeal cells (58.0%+/-3.8) morphologically similar to Methanosarcina and hydrogenotrophic methanogen rods were predominant over bacterial cells (41.0%+/-4.5), which resembled acetate-oxidizing rods and Desulfotomaculum morphologies. The percentage of sulfate-reducing bacteria cells (SRB) ranged from 12.2% (+/-2.5) to 21.7% (+/-2.8) in the biofilms and from 13.3% (+/-3.6) to 21.7% (+/-4.3) of the DAPI stained cells in suspension culture.

Archaea↗
PubMed2001

[Epidural spinal cavernous angioma: case report].

Epidural spinal cavernous angiomas account for approximately 4% of all spinal epidural tumors. More recently the diagnosis has become more frequent due to refinement of imaging modalities. We describe a 50-year-old woman with a spinal epidural cavernous angioma at L1-L2, which was successfully surgical treated. Clinical picture, imaginology and treatment of this entity is reviewed.

Epidural Neoplasms↗
PubMed2001

[Meningiomas in pediatric patients: report of 2 cases].

Meningiomas correspond to 1% - 4% of primary intracranial tumors in pediatric group, with their incidence raising according to age. There is not gender prevalence, in spite of some authors describe a male tendency opposed to female one in adulthood. At present study we describe two cases of pediatric meningiomas reviewing clinical, radiological and histological aspects of these lesions. The authors review also treatment options and prognosis of childhood meningiomas. A two-year-old boy was admitted with seizures. Computerized tomography showed a right parietal lesion, which was totally resected. Histological features were compatible with meningioma. After 17 months the child is doing well, with no deficits or seizures. The second case is a 12-year-old girl, with a headache complain. During investigation, a CT revealed a right frontal lesion. She was operated under a right frontal craniotomy with total tumor resection. Nowadays she is asymptomatic, 20 months after surgery. Despite meningiomas in pediatric group are uncommon; they should be included in differential diagnosis list of expansive intracranial lesions of childhood.

Child↗
PubMed2001

[Uncommon presentation of central neurocytoma causing intraventricular hemorrhage: case report].

Central neurocytoma was first described by Hassoun et al. in 1982 as a well-differentiated tumor from neuronal origin. This tumor typically occurs in young adults, localized in the ventricular system. It usually presents as intracranial hypertension due to obstructive hydrocephalus. The differential diagnosis should be done with others intraventricular tumors as oligodendroglioma, subependymoma and choroidal plexus papilloma. There are few cases of central neurocytoma presented by intraventricular hemorrhage in the literature. We report a case of 35 year-old woman, who presented with obstructive hydrocephalus due to intraventricular hemorrhage within the tumor. MRI revealed a tumor localized in the right lateral ventricle. Histopathological and immunohystochemical analysis confirmed the diagnosis of central neurocytoma. We review options for the treatment of this entity as well reinforce the inclusion of central neurocytoma as a differential diagnosis for intraventricular hemorrhage.

Adult↗
PubMed1997

Cell lines containing and expressing the human herpesvirus 6A ts gene are protected from both H-ras and BPV-1 transformation.

Human herpesvirus 6A (HHV-6A) strain U1102 was previously shown to contain a 1473 bp transformation suppressor gene (ts) (Araujo et al., 1995). Ts inhibited transformation of NIH3T3 cells by H-ras and transcription of the H-ras and human immunodeficiency type 1 (HIV-1) promoters in transient transfection experiments. In the current study, stable NIH3T3 cell lines expressing ts protein were established by transfection with pRc-ts containing the ts gene under the control of the Rous sarcoma virus (RSV) long terminal repeat (LTR) and a neomycin selectable marker. Selected cell lines contained approximately one to two copies per cell of intact ts sequences, expressed ts protein and grew at approximately the same rate as parental NIH3T3 cells. These cell lines were protected from H-ras transformation while parental and NIH3T3 cells containing the ts gene cloned in the antisense orientation were not. Expression of the chloramphenicol acetyl transferase (CAT) gene under the control of the EJ-H-ras promoter was also suppressed in the ts cell lines but not when the CAT gene was under the control of the murine osteosarcoma virus LTR or human cytomegalovirus immediate early promoter. When NIH3T3 cell lines expressing ts protein were established by infection with the retrovirus, LNCts, the cells expressed ts protein and were protected from H-ras transformation. Furthermore, bovine papillomavirus type 1 (BPV-1) transformation was also suppressed in cells co-transfected with BPV-1 plus ts and in ts expressing cell lines transfected with BPV-1. The BPV-1 p89 and p2443 promoters were down-regulated in 3T3-ts lines. Because the human papillomavirus type 16 (HPV-16) p97 promoter has similarity to the BPV-1 p89 promoter, the ability of ts to suppress p97 was also tested. Like the H-ras and BPV-1 promoters, HPV-16 p97 was down-regulated in 3T3-ts lines. The data indicate the utility of ts against H-ras, BPV-1 and HPV-16 promoters and their respective oncogenes.

3T3 Cells↗
PubMed1996

Human cytomegalovirus mtrII oncoprotein binds to p53 and down-regulates p53-activated transcription.

The 79-amino-acid (79-aa) open reading frame (UL111a) gene within morphological transforming region II (mtrII) of human cytomegalovirus strain Towne has been shown to transform rodent cells in vitro (J. Thompson, J. Doniger, and L. J. Rosenthal, Arch. Virol. 136:161-172, 1994). Moreover, a translation termination linker (TTL) mutant of mtrII that coded for the first 49 aa of mtrII oncoprotein (designated TTL49) was sufficient for malignant transformation, whereas a TTL mutant that coded for the first 24 aa (designated TTL24) was not. The current study demonstrates the binding of mtrII oncoprotein to the tumor suppressor protein p53 both in vivo using transiently transfected cells and in vitro using labeled proteins. Furthermore, the C-terminally truncated mtrII protein TTL49, but not truncated protein TTL24, bound to p53. The mtrII binding domain mapped to the N-terminal region of p53, residues 1 to 106, with a critical region from aa 27 to 44, whereas the p53 binding domain of mtrII protein was the first 49 aa. Furthermore, mtrII inhibited p53-activated transcription, indicating its ability to alter p53-directed cellular regulatory mechanisms. mtrII oncoprotein was detected both in stably transfected NIH 3T3 cell lines and human cytomegalovirus-infected HEL 299 cells (as early as 12 h after infection) in the perinuclear region and in the nucleus. mtrII-transformed cell lines, at both early and late passage, exhibited high levels of p53 with a 15-fold-extended half-life. However, p53-activated transcription was suppressed in these cells in spite of the increased p53 levels. Finally, the results with wild-type mtrII and its TTL mutants with respect to p53 binding, p53-activated transcription, and transforming ability suggest that the mechanism of mtrII transformation is linked to both p53 binding and disruption of p53 cell regulation.

3T3 Cells↗
PubMed1995

Human herpesvirus 6A ts suppresses both transformation by H-ras and transcription by the H-ras and human immunodeficiency virus type 1 promoters.

Human herpesvirus 6 strain U1102 (HHV-6A) was shown to contain a 1,473-bp functional transformation suppressor gene (ts). ts exhibited 24% identity and 51% similarity to adeno-associated virus type 2 Rep68/78. Like adeno-associated virus type 2 Rep68/78, HHV-6A ts suppressed H-ras transformation of NIH 3T3 cells. Suppression of H-ras transformation was eliminated by translation termination linker mutation at amino acid 25, 125, or 245. These data indicated the importance of the C-terminal portion of the ts protein. H-ras transformation was suppressed by ts only when H-ras was expressed by its endogenous H-ras promoter and not when it was expressed by the heterologous murine osteosarcoma virus long terminal repeat (LTR). Furthermore, ts suppressed chloramphenicol acetyltransferase (CAT) activity when the CAT gene was expressed from the H-ras promoter but not the murine osteosarcoma virus LTR promoter. Taken together, the data showed that ts suppressed H-ras transformation at the level of the H-ras promoter. To further identify the interaction of ts with transcriptional regulatory elements, the human immunodeficiency virus type 1 (HIV-1) LTR was used. This promoter was selected because it has well-defined transcriptional regulatory elements for both basal and activated transcription, because its activity is inhibited by the Rep68/78 gene, and because both HHV-6 and HIV-1 naturally infect CD4+ T cells in vivo and have been shown to infect the same cell in vitro. ts suppressed expression from both wild-type and upstream mutant HIV-1 LTR-CAT constructs. However, downstream HIV-1 TAR mutations reversed ts suppression, indicating that TAR is one of the critical elements involved. The data presented demonstrated that HHV-6A ts functionally suppressed H-ras transformation and HIV-1 LTR expression and thus that it may be useful in future gene therapy.

3T3 Cells↗
PubMed1982

[Myelopathy induced by anticoagulant medication. Report of a case with spinal epidural hematoma].

A 51 year-old female patient, under anticoagulant therapy due to thrombophlebitis and pulmonary embolism, developed sudden paraplegia. Emergency myelogram showed a total block at L2 level and an epidural hematoma was removed at surgery, but the motor deficit remained unchanged post-operatively. The pertinent literature is reviewed, etiological considerations are made and emphasis is placed on early diagnosis and prompt treatment.

Anticoagulants↗
PubMed1975

Meningiomas of Meckel's cave.

A retrospective review of 12 cases of meningioma of Meckel's cave involving the Gasserian ganglion or the trigeminal posterior root (or both) seen at the Mayo Clinic during a 20-year period suggested three clearly defined clinical groups. One group (the largest) had typical trigeminal neuralgia and an excellent prognosis after the removal of the easily detachable mass that was impinging on the ganglion. A second group, with meningiomas en plaque embedded in the ganglion, had a history of atypical trigeminal face pain without neurological deficit, but the prognosis for pain relief was not as good as in the previous group. A third group had a history of face dysesthesias and pain, objective trigeminal sensory loss, and multiple cranial nerve deficit; these patients had meningiomas with histological signs of mitotic activity and a poor prognosis, with return of intractable pain and recurrence of the tumor.

Adult↗
PubMedDate not supplied

The computed tomographic spectrum of cerebral cysticercosis.

The main findings observed in computed tomography (CT) of the brain of 116 patients with cerebral cysticercosis are reviewed. Calcifications, cysts, nodules, hydrocephalus and inflammatory reactions are better detected by CT than through the use of any of the conventional neuroradiologic procedures, and surgical cases are more properly selected.

Brain Diseases↗
PubMedDate not supplied

Unusual computed tomographic presentation of cerebral toxoplasmosis.

The computed tomographic appearance of three cases of cerebral toxoplasmosis is described. Two of the patients were children with Hodgkin disease and the third was an adult with systemic lupus erythematosus. All patients were severely immunosuppressed. Computed tomography showed single or multiple hypodense rounded areas with peripheral annular contrast enhancement, suggesting pyogenic cerebral abscesses. Pathologic correlation is presented. The importance of diagnosis and early treatment is emphasized.

Adult↗