Biomedical subjects

A L Amaral

Publications and source records attributed to A L Amaral.

10 recordsLinked to original sources

PubMed2004

Development of image analysis techniques as a tool to detect and quantify morphological changes in anaerobic sludge: II. Application to a granule deterioration process triggered by contact with oleic acid.

Image analysis techniques are applied to monitor the morphological changes in granular sludge present in an expanded granular sludge blanket (EGSB) reactor fed with oleic acid. Deterioration of granular sludge was monitored along the trial period by measuring the percentage of aggregates smaller than 1 mm (in terms of Feret diameter) either in terms of projected area or in terms of number of aggregates. A good correlation was obtained between these values and the percentage of aggregates smaller than 1 mm were physically sorted and quantified by the volatile suspended solid content. The ratio of total filaments length to cross-sectional area of aggregates defined as LfA, was applied to quantify the dispersion level of the granular sludge, which increased until day 141 and remained almost invariant afterwards. LfA was sensitive to the sludge deterioration process and was able to indicate, with the anticipation of about 1 month, the most significant biomass washout episode that occurred in the trial period. A mechanism of filaments' release, detachment and selective washout was proposed to explain the action of LfA from this viewpoint. The equivalent diameter of the bottom aggregates larger than 1 mm increased with the increase on the amount of long chain fatty acids associated with the biomass by mechanisms of adsorption, precipitation, or entrapment. After a threshold value of about 200 mg COD-LCFA gVSS (COD = chemical oxygen demand; LCFA = long chain fatty acids; VSS = volatile suspended solids), a migration of granular sludge from the bottom to a top-floating layer was evident.

Anaerobiosis↗

PubMed2004

Development of image analysis techniques as a tool to detect and quantify morphological changes in anaerobic sludge: I. Application to a granulation process.

Image analysis techniques were developed and applied to quantify the process of anaerobic granulation in an expanded granular sludge blanket reactor (EGSB) fed with a synthetic substrate based on glucose [60-30% COD (chemical oxygen demand)] and volatile fatty acids (40-70% COD) over 376 days. In a first operation period that lasted 177 days, the aggregation of dispersed sludge was quantitatively monitored through the recognition and quantification of aggregates and filaments. A parameter defined as the ratio between the filaments' length and the aggregates projected area (LfA) has proven to be sensitive to detect changes in the aggregation status of the anaerobic sludge. The aggregation time-defined as the moment when a balance between filaments' length and aggregates' size was established-was recognized through the LfA. The percentage of projected area of aggregates within three size ranges (0.01-0.1 mm, 0.1-1 mm, and >1 mm, equivalent diameter) reflected the granular size spectrum during the aggregation process. When sudden increases on the upflow velocity and on the organic loading rate were applied to the previously formed granules, the developed image analysis techniques revealed to be good indicators of granular sludge stability, since they were sensitive to detected filaments release, fragmentation, and erosion that usually leads to washout. The specific methanogenic activities in the presence of acetate, propionate, butyrate, and H(2)/CO(2) increased along the operation, particularly relevant was the sudden increase in the specific hydrogenophilic activity, immediately after the moment recognized as aggregation time.

Algorithms↗

PubMed2004

Effect of hyperbaric stress on yeast morphology: study by automated image analysis.

The effects of hyperbaric stress on the morphology of Saccharomyces cerevisiae were studied in batch cultures under pressures between 0.1 MPa and 0.6 MPa and different gas compositions (air, oxygen, nitrogen or carbon dioxide), covering aerobic and anaerobic conditions. A method using automatic image analysis for classification of S. cerevisiae cells based on their morphology was developed and applied to experimental data. Information on cell size distribution and bud formation throughout the cell cycle is reported. The results show that the effect of pressure on cell activity strongly depends on the nature of the gas used for pressurization. While nitrogen and air to a maximum of 0.6 MPa of pressure were innocuous to yeast, oxygen and carbon dioxide pressure caused cell inactivation, which was confirmed by the reduction of bud cells with time. Moreover, a decrease in the average cell size was found for cells exposed for 7.5 h to 0.6 MPa CO2.

Air Pressure↗

PubMed2003

Morphological analysis of Yarrowia lipolytica under stress conditions through image processing.

Stress conditions (thermal and oxidative) were applied to Yarrowia lipolytica culture. A rearrangement in cell metabolism as well as dimorphism was observed under these conditions. An image analysis procedure was employed for morphology characterization, and a net increase of around 25% on hyphae formation was detected. A significant increment in total hyphal length was detected, compared with the control system. The results obtained lead to the consideration of a possible relationship between dimorphism and a cell response mechanism to stress conditions.

Journal Article↗

PubMed2003

Automated image analysis to improve bead ingestion toxicity test counts in the protozoan Tetrahymena pyriformis.

AIMS: To improve bead ingestion counts in Tetrahymena pyriformis by automated image analysis as an alternative to direct-counts. METHODS AND RESULTS: Fluorescent latex beads were added to T. pyriformis cultures for ingestion tests. The number of beads ingested by 25 cells was counted directly by epifluorescence microscopy and compared with similar data from image analysis. anova indicated that counts were not significantly different (P < 0.05). The image analysis particularly provided advantages in terms of speed. CONCLUSIONS: The image analysis is superior to direct beads counting in T. pyriformis particularly in terms of speed of analysis. SIGNIFICANCE AND IMPACT OF THE STUDY: The image analysis method is very rapid and will allow many more toxicological analyses to be undertaken with less operator error.

Animals↗

PubMed2003

Image analysis, methanogenic activity measurements, and molecular biological techniques to monitor granular sludge from an EGSB reactor fed with oleic acid.

Morphological changes in anaerobic granular sludge fed with increasing loads of oleic acid were quantified by image analysis. The combination of this technique with data on the accumulation of adsorbed long chain fatty acid and with the molecular characterization of microbial community gave insight into the mechanisms of sludge disintegration, flotation and washout. It was found that the bacterial domain was more affected than the archaeal domain during this process. However, no acetoclastic activity and onlya residual hydrogenotrophic activity were detected in the sludge at the end of the operation.

Adsorption↗

PubMed1986

Adenoid cystic carcinoma of salivary glands. A study of 61 cases with clinicopathologic correlation.

Sixty-one cases of adenoid cystic carcinoma of the head and neck region, excluding the ear canal, lacrimal glands, larynx, esophagus, and trachea, were studied, and their different clinicopathologic aspects were analyzed. Adenoid cystic carcinoma occurred more commonly in the minor salivary glands; the palate was affected in 31% of the cases. The fifth decade of life was the age at which patients were most commonly affected, and there was a slight predominance of white women. In most patients a mass was the main complaint; in 63% the duration of symptoms was 1 year or less. Forty-one patients had Stages 3 or 4 disease when first seen, and 51.7% of the patients died of disease, with a mean survival period of 35.4 months. Three basic patterns of growth, solid, cribriform, and tubular, were identified in the histopathologic examination of the cases. Other pathologic aspects analyzed were cellular pleomorphism, mitotic activity, necrosis, vascular invasion, and perineural infiltration. The study revealed a positive correlation between location of the tumor, clinical staging, duration of symptoms, and histologic pattern of growth with the prognosis of the lesion. Tumors located in the minor salivary glands, those in which the duration of symptoms was less than 1 year, and those that showed advanced clinical staging and a predominantly solid pattern of growth had an extremely poor prognosis. Surgery is the treatment of choice of adenoid cystic carcinoma, and microscopically free surgical lines of resection must be obtained. Radiation therapy, although not curative, plays an important role in prolonging survival.

Adolescent↗

PubMed1984

Malignant lymphoepithelial lesion of the submandibular gland.

A case of malignant lymphoepithelial lesion of the submandibular gland is reported and the literature is reviewed. This neoplasm has been described frequently in Eskimos and is usually located in the parotid gland. The histogenesis of the lesion is discussed. The tumor shows local aggressiveness, with frequent recurrences and metastases to regional lymph nodes. Surgical treatment consisting of wide resection of the tumor with regional lymph node dissection, with or without radiotherapy, seems to be the most appropriate therapy.

Aged↗

PubMed1984

Proliferating pilar (trichilemmal) cyst. Report of two cases, one with carcinomatous transformation and one with distant metastases.

We examined two cases of proliferating pilar cysts of the inguinal region. One of the cases showed a transformation to epidermoid carcinoma and, despite surgical resection, the patient died by means of distant generalized metastases. The diagnosis of proliferating pilar cyst should be made in pilar cysts with epithelial proliferation that shows well-defined borders and abundant keratinization despite cytologic atypia and mitotic activity. The diagnosis of carcinoma in proliferating pilar cysts should be reserved for lesions showing poorly defined borders and clear-cut infiltrative properties with cytologic evidence of malignancy.

Aged↗

PubMedDate not supplied

[Polyneuropathy deficiency among Xavante indians].

UNLABELLED: The authors present two cases of polyneuropathy deficiency among Xavante indians where the sole food was rice in case 1 and almost so in case 2. The rice consumed by these indians was processed or hulled. Intoxication by cyanide from maniot or other vegetable was excluded. CASE REPORT: Two indians aged 18 and 25 years with a progressive history of weaness, decrease in muscular force and thinning were observed in their villages. On removal to the Hospital São Paulo, atrophy of the distal musculature of the upper and lower limbs, motor deficit distally with zero degree in the flexor musculature, abolished deep reflexes, plantar cutaneous reflex without response bilaterally, decreased tactile, painful and pallesthetic sensitivity distally in the lower limbs were noted on neurological examination of case 1. On neurological examination of case 2 proximal hyporeflexia in the upper limbs, areflexia in the distal portions of the upper and lower limbs, tactile and painful hypoesthesia in the feet, right hypoacousis were noted. Electromyography showed abnormalities compatible with symmetric sensorimotor polyneuropathy with an axonal demyelination pattern in case 1 and predominantly demyelinizing in case 2. Cerebrospinal fluid tests were normal. DISCUSSION: Polyneuropathy was characterized by the clinical history and by neurological, electromyographic and cerebrospinal fluid tests. The diagnosis of polyneuropathy deficiency was established by the clinical history and by electromyography suggesting peripheral polyneuropathy of nutritional origin. This neuropathy deficiency does not fit myeloneuropathies such as ataxic tropical neuropathy, spastic paraparesis and Cuba neuropathy. CONCLUSION: The Xavante polyneuropathy deficiency is caused by thiamine (vitamin B1) deficiency, that is dry beriberi, owing to consumption of industrially processed rice as sole or almost sole food. The Xavante polyneuropathy is different from the neuropathy observed among Kreen-Akrore indians and from that of adolescent indians in the Xingu Park.

Adolescent↗