Search PubMed⌕ Search

Biomedical subjects

C A Sousa

Publications and source records attributed to C A Sousa.

At least 19 recordsLinked to original sources
PubMed2002

Male size does not affect mating success (of Anopheles gambiae in São Tomé).

For malaria control, the utility of transgenic vector Anopheles mosquitoes (Diptera: Culicidae) refractory to Plasmodium transmission, will depend on their interbreeding with the wild vector population. In many species, larger males are more successful in obtaining mates. In São Tomé island, we determined that size did not affect mating success of male Anopheles gambiae Giles sensu stricto, the main malaria vector in tropical Africa. Also we showed that larval intraspecific competition is probably insignificant in this population of An. gambiae. Thus, the potential success of transgenic An. gambiae is unlikely to be affected by size selection under field conditions.

Animals↗
PubMed2001

The ACVD task force on canine atopic dermatitis (II): genetic factors.

Canine atopic dermatitis is commonly diagnosed in pruritic animals. Many studies have attempted to determine the inheritance pattern of both atopic dermatitis and of elevated allergen-specific IgE production. Despite many clinical, laboratory and breeding studies, the mode of inheritance and genetic mutations underlying this disease currently remain elusive.

Animals↗
PubMed2001

The ACVD task force on canine atopic dermatitis (XX): glucocorticoid pharmacotherapy.

Glucocorticoids (GCs) have been the most commonly prescribed drugs for treatment of canine atopic dermatitis (AD) during the last decades. In spite of this widespread usage, there are a few studies documenting their efficacy. Fortunately, recently completed clinical trials were designed with oral GCs used as "standard of care" for treatment of canine AD. These studies provided high quality evidence in favor of the strong efficacy of oral low-dose glucocorticoid formulations to control skin lesions and pruritus in dogs with AD. Consequently, there is good evidence to support the recommendation of use of oral glucocorticoids for treatment of canine AD.

Administration, Oral↗
PubMed2001

The ACVD task force on canine atopic dermatitis (XI): the relationship between arthropod hypersensitivity and atopic dermatitis in the dog.

The relationship between arthropod allergen hypersensitivity and the development of canine atopic dermatitis (AD) is unclear. It has been shown that dogs with AD are more likely to exhibit positive intradermal reactivity to flea allergens than non-pruritic dogs from the same flea-endemic geographic region. Also, dogs in a flea endemic region are four times more likely to suffer from flea allergy dermatitis (FAD) and AD than from FAD alone. These results provide indirect evidence to support the hypothesis that, in the canine species, atopy predisposes to the development of hypersensitivity to flea allergens and eventually to FAD. A causal relationship between insects other than fleas and canine AD has not been identified with certainty.

Animals↗
PubMed2001

The ACVD task force on canine atopic dermatitis (XIX): general principles of therapy.

The treatment of canine atopic dermatitis is multifaceted and consists of a combination of actions that include the use of allergen avoidance, anti-inflammatory agents, allergen-specific immunotherapy and antimicrobial drugs. The importance and order of these treatment steps vary from patient to patient. General recommendations for each of the therapeutic steps are highlighted in this paper. Specific details are covered in other papers of this issue.

Animals↗
PubMed2001

Dogs as a favored host choice of Anopheles gambiae sensu stricto (Diptera: Culicidae) of São Tomé West Africa.

The host source and human blood index (HBI) of an exophilic population of the "forest" cytoform of Anopheles gambiae Giles sensu stricto, from a peri-urban area of the island of São Tomé were assessed. Blood meals of 434 An. gambiae females from all-night indoor light-trap collections, 193 from indoor and 422 from outdoor resting collections, were determined by ELISA. Significant differences were found in the HBI estimates from insects collected indoors (0.93) and outdoors (0.27). Blood-fed insects collected resting outdoors provided the most representative sample for host determination. Dogs were the predominant hosts, followed by humans and pigs. Of all human feeds, it was estimated that 81.5% were taken inside houses. The low HBI of 0.27 for the An. gambiae population explains the low sporozoite rate and the meso-endemicity of malaria in the island.

Africa, Western↗
PubMed2000

Malaria in São Tomé and Príncipe: parasite prevalences and vector densities.

A cross-sectional survey was carried out in 16 localities on the island of São Tomé and three on the island of Príncipe, at the end of the rainy season of 1997, to determine malaria prevalence and vector densities. Blood samples from 664 inhabitants of all ages were examined by optical microscopy (OM) and PCR. Mosquito collections were made by outdoor landing captures from 21:00-23:00 h. Great differences were found between OM and PCR readings. OM had a sensitivity of 66%, a specificity of 79% and failed to reveal any mixed-infections. Overall prevalence, determined by PCR, was higher in São Tomé (53%) than in Príncipe (35%). It was highest in children below 16 years-old. All four human Plasmodium species occurred in São Tomé but P. ovale was not detected in Príncipe. The human population was largely asymptomatic. Bednet users had lower prevalence than did non-users. The FOREST form of Anopheles gambiae s.s., identified by PCR and cytogenetics, was the only vector on the islands. The sporozoite rate in São Tomé, assessed by ELISA, was 0.5%. Parasite prevalence and vector densities were positively correlated in São Tomé, where malaria transmission must occur predominantly in the more populated coastal areas.

Adolescent↗
PubMed2000

Complex segregation analysis of deafness in Dalmatians.

OBJECTIVE: To use pedigree analysis to evaluate the feasibility of a major locus model for deafness in Dalmatians. ANIMALS: 605 purebred Dalmatians from 42 families. PROCEDURE: Hearing loss was evaluated through the brainstem auditory-evoked response. Dogs were classified into mutually exclusive categories: normal hearing, unilaterally deaf, or bilaterally deaf. Information was collected on sex, coat color, presence or absence of a color patch at birth, and eye color. Statistical analyses were performed by use of regressive logistic models designed for complex segregation analysis. Genetic correlations among eye color, deafness, and color patch were estimated. RESULTS: Prevalence of hearing loss was 11% for dogs classified as unilaterally deaf and 5% for dogs that were bilaterally deaf. Complex segregation analysis detected statistical evidence of a single allele with an expected frequency of 0.21 that had an effect on the prevalence of deafness. Results of analyses suggested that this locus cannot completely explain the inheritance and incidence of deafness in Dalmatians. Genetic correlation estimates among deafness, eye color, and color patch revealed strong interrelationships among these characteristics. CONCLUSIONS AND CLINICAL RELEVANCE: To reduce the incidence of hearing loss in Dalmatians, unilaterally deaf, blue-eyed dogs should not be considered as potential parents.

Alleles↗
PubMed1999

Neutral lipids induce critical behavior in interfacial monolayers of pulmonary surfactant.

We have shown previously that lateral compression of pulmonary surfactant monolayers initially induces separation of two phases but that these remix when the films become more dense (1). In the studies reported here, we used fluorescence microscopy to examine the role of the different surfactant constituents in the remixing of the separated phases. Subfractions containing only the purified phospholipids (PPL), the surfactant proteins and phospholipids (SP&PL), and the neutral and phospholipids (N&PL) were obtained by chromatographic separation of the components in extracted calf surfactant (calf lung surfactant extract, CLSE). Compression of the different monolayers produced nonfluorescent domains that emerged for temperatures between 20 and 41 degreesC at similar surface pressures 6-8 mN/m higher than values observed for dipalmitoyl phosphatidylcholine (DPPC), the most prevalent component of pulmonary surfactant. Comparison of the different preparations showed that the neutral lipid increased the total nonfluorescent area at surface pressures up to 25 mN/m but dispersed that total area among a larger number of smaller domains. The surfactant proteins also produced smaller domains, but they had the opposite effect of decreasing the total nonfluorescent area. Only the neutral lipids caused remixing. In images from static monolayers, the domains for N&PL dropped from a maximum of 26 +/- 3% of the interface at 25 mN/m to 4 +/- 2% at 30 mN/m, similar to the previously reported behavior for CLSE. During continuous compression through a narrow range of pressure and molecular area, in N&PL, CLSE, and mixtures of PPL with 10% cholesterol, domains became highly distorted immediately prior to remixing. The characteristic transition in shape and abrupt termination of phase coexistence indicate that the remixing caused by the neutral lipids occurs at or close to a critical point.

Animals↗
PubMed1999

A clonal Plasmodium falciparum population in an isolated outbreak of malaria in the Republic of Cabo Verde.

We present the first parasitological, molecular and longitudinal analysis of an isolated outbreak of malaria. This outbreak occurred on Santiago Island (Republic of Cabo Verde), a region where malaria is hypoendemic and controlled, and thus the population is considered non-immune. Blood samples were collected from the inhabitants over 1 month and during cross-sectional surveys in the following year. The presence and nature of the parasites was determined by PCR. Plasmodium falciparum was the only species detected. Genetic analysis revealed that the circulating parasites were genetically homogeneous, and probably clonal. Gametocytes were found throughout this period. Our data suggest that this represented a focal outbreak, resulting in the infection of at least 40% of the villagers with a clonal parasite line. Thus, P. falciparum infections can persist for at least 1 year in a substantial proportion (10%) of the hosts. Implications for malaria control and the interpretation of epidemiological data are discussed.

Africa, Western↗
PubMed1996

A threshold model analysis of deafness in Dalmatians.

To elucidate the inheritance of deafness in Dalmatian dogs, 825 dogs in 111 litters were evaluated for abnormalities in hearing through the brainstem auditory evoked response (BAER). Recorded along with their quality of hearing (normal, unilaterally deaf, or bilaterally deaf) were the sex, coat color, eye color and the presence or absence of a color patch. The analysis considered deafness an ordered categorical trait in a threshold model. The underlying, unobservable continuous variate of the threshold model was assumed to be a linear function of sex of dog, coat color (black or liver and white), color patch (presence or absence), eye color, the deafness phenotype of the parents and a random family effect. Twenty-six percent of dogs were deaf in at least one ear. Eye color, color patch, sex and the hearing status of the parents were all significant contributions to deafness. The heritability of deafness, on the continuous unobservable scale, was 0.21. This value was computed after correction for eye color, color patch, parental hearing status and sex, implying that significant genetic variation exists beyond the contribution of several single loci.

Animals↗
PubMed1995

Exudative, crusting, and scaling dermatoses.

This article discusses the differential diagnoses for the dermatologic diseases of the cat that present with the primary owner complaint of scaling, crusting, and exudation. Clinical signs, diagnostic tests, and therapies are included for each disease.

Animals↗
PubMed1995

[Systemic lupus erythematosus in the elderly].

The authors report two clinical cases of systemic lupus erythematosus, both in patients over 65 years of age. The discussion includes a brief overview of recent publications on this condition in geriatric patients. Some aspects of systemic lupus in elderly persons are suggested and commented on.

Aged↗
PubMed1994

[Angiosarcoma of the spleen].

Primitive splenic tumors are extremely rare. We report a case, the first at S. José-Hospitais Civis de Lisboa, of a 70 year old woman who presented splenomegaly. She had pelvic irradiation in her past history. MRI revealed a splenic mass characterized as vascular on angiography. She is doing well 12 months after splenectomy. We have found 61 reported cases of this rare tumor whose etiopathogeny is unknown. Early splenectomy should be the first therapeutical approach, since spontaneous rupture is very common and was the feature presented in 34% of patients in the series by Autry et al. As far as cytostatic chemotherapy is concerned, the rarity of this tumor precludes any conclusion about its efficacy, but in metastasized forms it seems that chemotherapy for soft tissue sarcomas may be effective.

Aged↗