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Biomedical subjects

P Carvajal

Publications and source records attributed to P Carvajal.

11 recordsLinked to original sources
PubMed2001

Frequency of CCR5 gene 32-basepair deletion in Chilean HIV-1 infected and non-infected individuals.

A 32-basepair deletion polymorphism in the CCR5 chemokine receptor gene (CCR5Delta32) has been identified and shown to have functional significance in determining susceptibility to infection by human immunodeficiency virus type 1 (HIV-1) and possibly in influencing disease progression in HIV-1 positive individuals. These findings led to an interest in studies of DeltaCCR5 allele geographical distribution in human population, for complete understanding of the role of CCR5 in HIV-1 epidemiology. Inter-population variation in CCR5Delta32 frequency may be a significant factor in the prediction of AIDS endemicity. In this report we assessed the frequency of DeltaCCR5 in a Chilean population (63 HIV-1 infected and 62 non-infected individuals). No homozygous CCR5Delta32 individual was identified, and no significant difference was observed between HIV-1 infected (3/63) and non-infected (3/62) individuals for the heterozygote CCR5Delta32 state. This is the first evidence of the contribution of DeltaCCR5 allele to the genetic background of the Chilean population, which is characterized by intense ethnic admixture and by gene flow from the European Spanish gene pool.

Chile↗
PubMed2000

Rheological and physicochemical properties of starches from moist- and dry-type sweetpotatoes.

Although starch makes up from 50 to 70% of sweetpotato (SP) dry matter, its role in cooked texture is unknown. The purpose of this research was to characterize raw starches isolated from SP cultivars and experimental selections (C/S) with a wide range of textural properties when cooked and to investigate the relationship between textural properties of the cooked roots and characteristics of the isolated starches. Shear stress measured by uniaxial compression of cooked SP cylinders served as an objective measure of SP texture. Starches were isolated from C/S representing three SP texture types: moist (Jewel and Beauregard); intermediate (NC10-28 and NC2-26); and dry (NC6-30 and NC8-22). The following parameters of isolated starches were measured: amylose content by colorimetric and differential scanning calorimetric (DSC) methods; swelling power, solubility, gelatinization enthalpy (DeltaH), and pasting properties by Brabender amylograph (BA) and rapid viscoanalyzer (RVA). Pasting temperatures for SP C/S measured by BA and RVA were significantly correlated. Due to high shear degradation in RVA, RVA viscosities of starch suspensions decreased as much as 40% during cooking at 95 degrees C, whereas the BA viscosities changed little at this temperature. There were no statistically significant differences among the C/S for amylose or DeltaH. However, significant C/S differences in swelling power, solubility, and pasting properties were observed. Although differences in some rheological and physical properties were observed for C/S starches, shear stress was statistically correlated only with DSC onset temperature (r = 0.78), indicating that factors other than the properties measured on isolated starches are mainly responsible for the texture of cooked SP C/S.

Calorimetry, Differential Scanning↗
PubMed1999

[Dental fluorosis: quantification of Streptococcus mutans in school children from Mamiña, Chile. A longitudinal study].

BACKGROUND: High fluorine concentrations in drinking water are associated with a decrease in the amount of salivary S mutants. Taking into account that clinical dental fluorosis can appear with 1.5 ppm of fluorine in the drinking water, fluorine concentrations in Mamiña is 2.4 ppm. AIM: To quantify salivary S mutans in school age children from Mamiña, a zone with a high fluorine content in the drinking water, during one year. MATERIAL AND METHODS: During 1997 and 1998, dental health was assessed and salivary samples were obtained from 51 children (27 male) aged 10 +/- 2 years to quantify S mutans. RESULTS: Most children studied had more than 10(5) salivary S mutans colony forming units. No changes in the rates of infection or dental health characteristics were observed during the observation year. CONCLUSIONS: High fluorine content in the drinking water did not have an effect on salivary S mutans infection in this population.

Child↗
PubMed1993

[Clinical usefulness of rheumatoid factor in synovial fluid. Re-evaluation].

The aim of this work is to analyze the usefulness of rheumatoid factor determination in synovial fluid. One hundred twenty nine patients (29 with rheumatoid arthritis), in whom rheumatoid factor was simultaneously determined in serum and synovial fluid, were retrospectively analyzed. Serum rheumatoid factor had a 48% sensitivity, 98% specificity, 88% positive predictive value and 87% negative predictive value for the diagnosis of rheumatoid arthritis. These numbers were 76, 79, 51 and 92% respectively for synovial fluid rheumatoid factor. In rheumatoid arthritis of less than one year of evolution, serum and synovial rheumatoid factor have a sensitivity of 15% and 62% respectively, a positive predictive value of 50 and 28% respectively and a negative predictive value of 90 and 94% respectively. It is thus concluded that the absence of rheumatoid factor in serum and synovial fluid in a patient with arthritis of less than one year of evolution, renders the diagnosis of rheumatoid arthritis very unlikely. Likewise the simultaneous presence of rheumatoid factor in both fluids has a high diagnostic certainty. Among other studied variables, leukocyte count, C3 and C4 levels in synovial fluid are the best discriminators within the different diagnostic groups.

Arthritis, Rheumatoid↗
PubMed1984

Erythrocyte and HLA antigens of Atacameño Indians.

The present study reports the results of erythrocyte antigen typing for the following systems: ABO, MN, Rh, Kell, Duffy, and Diego in roughly 180 Atacameño Indians from the oasis of Toconao, northern Chile. A subsample was tested for variation at the histocompatibility loci A, B, and C. Results agree with previous findings based on smaller samples. Caucasian admixture of the Atacameño from Toconao was estimated to be 0.056 +/- 0.022.

Blood Group Antigens↗
PubMedDate not supplied

[Post traumatic partial seizures].

INTRODUCTION: Post traumatic epilepsy represents 4% of the prevalence of the disorder and is one of the sequelas which is most difficult to prevent. Risk factors have been described to predict the appearance of seizures. CLINICAL CASE: A seven year old boy with a severe head injury was admitted to the Intensive Care Unit. On neuroimaging studies there were multiple foci of contusion, mainly in the left hemisphere, and blood in the III and IV ventricles and frontal horn of the left lateral ventricle. The patient had severe sequelae of head injury with a right spastic hemiplegia and hemiparesia with hypertony of the left side, together with complete blindness of both eyes due to bilateral atrophy of the optic nerve. Serial EEG were done, in which a recording showed alternating periods of hypervoltage grapho elements superimposed on a trace of very low voltage, with continuous activity of low voltage and low frequency. There were no grapho elements with acute morphology. However, the patient had a first partial seizure a year and a half after his head injury. On the EEG an epileptogenic focus was identified in the left hemisphere. Within two years of his head injury he had seven seizures. He had not received prophylactic antiepileptic treatment after the head injury. CONCLUSIONS: We report a case of epilepsy secondary to a head injury, in which the first seizure occurred one and a half years after injury. In view of the risk factors, we discuss whether prophylactic anti epileptic treatment might have been beneficial.

Brain↗
PubMedDate not supplied

[Landau kleffner syndrome].

INTRODUCTION: The Landau Kleffner syndrome (SLK) is associated with paroxystic alterations of the electroencephalogram which are intensified during sleep, with acquired aphasia and epilepsy, in 75 83% of the cases. The syndrome is associated with other features, such as personality disorders presenting as autistic behaviour, cognitive regression and in some cases, motor dysfunction. The epileptic activity appears to be responsible for the disorder. Treatment with anti epileptic drugs is ineffective in many cases, although there may be periods of spontaneous improvement, or there may be permanent sequelas of language. Design. A systematic revision of one case. CASE REPORT: A five year old boy with no previous clinical history had, at the age of four years, presented with behaviour changes and aphasia, accompanied by paroxystic changes on the EEG and nocturnal polysomnogram. On cranial CT there was a mid line cyst. He had had no seizures. Treatment. Treatment with carbamazepine led to clinical improvement in behaviour, reduction in the paroxysms and appearance of sleep spindles, but little effect on the degree of aphasia. CONCLUSIONS: The case described is a variant of SLK, with no epileptic seizures, some improvement on carbamazepine and a mid line cyst.

Anticonvulsants↗