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C Castro

Publications and source records attributed to C Castro.

At least 37 records · Page 2Linked to original sources
PubMed2000

Eleven novel APC mutations identified in Portuguese FAP families.

Germline mutations of the adenomatous polyposis coli (APC) gene are responsible for familial adenomatous polyposis (FAP), an autosomal dominant predisposition to colorectal cancer. In the present study we screened all of the exons of the APC gene in individuals belonging to 85 Portuguese FAP families. We here report eleven novel mutations which are predominantly frameshifts or single base substitutions, resulting in premature stop codons. Hum Mutat 16:178, 2000.

Adenomatous Polyposis Coli↗
PubMed2000

Compartment syndrome following intravenous regional anesthesia.

PURPOSE: To present two cases of upper extremity compartment syndrome following intravenous regional anesthesia. CLINICAL FEATURES: Case 1: A 57-yr-old man presented for surgical release of a left-hand Dupuytren's contracture. The procedure was performed under iv regional anesthesia with 360 mg lidocaine and sedation with 150 microg fentanyl and 1.5 mg midazolam. Tourniquet time was 107 min at a pressure of 260 mmHg using three different tourniquet sites. Within minutes of tourniquet release, increased forearm muscle tension, hand anesthesia, pallor, and limited motor function developed. Serum CK and myoglobin levels rose. Myoglobinuria was present. Several fasciotomies and aggressive fluid therapy were performed. Patient made almost full recovery. Case 2: A 73-yr-old woman with controlled hypertension had Dupuytren fasciotomy of her right hand under iv regional anesthesia with 200 mg lidocaine and sedation using 75 microg fentanyl and 1.5 mg midazolam. Tourniquet time was 64 min at a pressure of 250 mmHg using three different tourniquet sites. The patient complained of pain at the iv site during injection of local anesthetic, third tourniquet inflation and after deflation of tourniquet. Thirty minutes after arrival in PACU, her fingers were bluish. She complained of pain and swelling of the forearm. Under general anesthesia, fasciectomy was performed. Myoglobin and CPK levels rose. CPK MB was high but troponin was negative. Three days later she developed pulmonary embolism. She was heparinized and subsequently discharged home. She recovered completely. CONCLUSION: Compartment syndrome may have a rapid and severe onset. Etiology of our cases is still not established. We postulate that increased tissue pressure may be the cause. The anesthesiologists must be aware of compartment syndrome during regional anesthesia.

Aged↗
PubMed2000

Do changes in physical activity lead to dietary changes in middle and old age?

INTRODUCTION: Research examining the relationship between dietary factors and physical activity patterns has yielded conflicting findings. Few prospective studies have examined whether individuals who change their level of physical activity make corresponding changes in their diet. METHODS: The current study examined, in two randomized clinical trials of physical activity, whether self-report of dietary factors changed over a 1-year period, whether these changes differed by gender or exercise-intervention group, and whether changes in physical activity led to changes in dietary factors. Participants included 268 men and women aged 50-65 years who participated in the Stanford-Sunnyvale Health Improvement Project I (SSHIP-I) and 103 men and women aged 65-82 years who participated in SSHIP-II. In both trials we recruited participants through random-digit telephone dialing and citywide promotion. RESULTS: Overall, participants adopted healthier diets over the 1-year period. The SSHIP-I participants decreased their consumption of total calories, total fat, saturated fat, protein, and cholesterol. The SSHIP-II participants decreased their consumption of high-fat, high-cholesterol foods. The SSHIP-I women were more likely than men to decrease their intake of total fat and protein (p < 0.01), as well as total calories, saturated fat, and cholesterol (p < 0.05). However, we found that changes in physical activity were not associated with changes in self-report measures of dietary habits. CONCLUSIONS: We found no evidence to support the idea that changes in physical activity are a gateway for changes in dietary factors in middle-aged and older adults.

Aged↗
PubMed2000

Personal and environmental factors associated with physical inactivity among different racial-ethnic groups of U.S. middle-aged and older-aged women.

Personal, program-based, and environmental barriers to physical activity were explored among a U.S. population-derived sample of 2,912 women 40 years of age and older. Factors significantly associated with inactivity included American Indian ethnicity, older age, less education, lack of energy, lack of hills in one's neighborhood, absence of enjoyable scenery, and infrequent observation of others exercising in one's neighborhood. For all ethnic subgroups, caregiving duties and lacking energy to exercise ranked among the top 4 most frequently reported barriers. Approximately 62% of respondents rated exercise on one's own with instruction as more appealing than undertaking exercise in an instructor-led group, regardless of ethnicity or current physical activity levels. The results underscore the importance of a multifaceted approach to understanding physical activity determinants in this understudied, high-risk population segment.

Activities of Daily Living↗
PubMed2000

Cutaneous primary paracoccidioidomycosis.

Paracoccidioidomycosis is a common fungal infection in Latin America. Few cases have been described in non-endemic countries and their diagnosis without the correct suspicion, bearing in mind that the latency period might be up to 60 years, may not be easy. We report the case of a 59-year-old man who worked as a taxi driver for 25 years in Venezuela. Cutaneous paracoccidioidomycosis was diagnosed one year after he returned to Spain. No internal signs or symptoms of the disease were found and cell-mediated immunity showed no depression. Our case suggested us to consider direct cutaneous infection, although respiratory tract is believed to be the most frequent portal of entry for this infection.

Humans↗
PubMed2000

Molecular characterization and identification of biocontrol isolates of Trichoderma spp.

The most common biological control agents (BCAs) of the genus Trichoderma have been reported to be strains of Trichoderma virens, T. harzianum, and T. viride. Since Trichoderma BCAs use different mechanisms of biocontrol, it is very important to explore the synergistic effects expressed by different genotypes for their practical use in agriculture. Characterization of 16 biocontrol strains, previously identified as "Trichoderma harzianum" Rifai and one biocontrol strain recognized as T. viride, was carried out using several molecular techniques. A certain degree of polymorphism was detected in hybridizations using a probe of mitochondrial DNA. Sequencing of internal transcribed spacers 1 and 2 (ITS1 and ITS2) revealed three different ITS lengths and four different sequence types. Phylogenetic analysis based on ITS1 sequences, including type strains of different species, clustered the 17 biocontrol strains into four groups: T. harzianum-T. inhamatum complex, T. longibrachiatum, T. asperellum, and T. atroviride-T. koningii complex. ITS2 sequences were also useful for locating the biocontrol strains in T. atroviride within the complex T. atroviride-T. koningii. None of the biocontrol strains studied corresponded to biotypes Th2 or Th4 of T. harzianum, which cause mushroom green mold. Correlation between different genotypes and potential biocontrol activity was studied under dual culturing of 17 BCAs in the presence of the phytopathogenic fungi Phoma betae, Rosellinia necatrix, Botrytis cinerea, and Fusarium oxysporum f. sp. dianthi in three different media.

DNA, Mitochondrial↗
PubMed2000

The tprK gene is heterogeneous among Treponema pallidum strains and has multiple alleles.

We have previously shown that the TprK antigen of T. pallidum, Nichols strain, is predominantly expressed in treponemes obtained 10 days after infection and that the hydrophilic domain of TprK is a target of opsonic antibodies and confers significant protection against homologous challenge. The T. pallidum genome sequence reported the presence of a single copy of the tprK gene in the Nichols strain. In the present study we demonstrate size heterogeneity in the central portions of the TprK hydrophilic domains of 14 treponemal isolates. Sequence analysis of the central domains and the complete open reading frames (ORFs) of the tprK genes confirms this heterogeneity. Further, multiple tprK sequences were found in the Nichols-defined tprK locus in three isolates (Sea 81-4, Bal 7, and Bal 73-1). In contrast, only a single tprK sequence could be identified in this locus in the Nichols strain. Alignment of the DNA and deduced amino acid sequences of the whole tprK ORFs shows the presence of seven discrete variable domains flanked by highly conserved regions. We hypothesize that these heterogeneous regions may be involved in antigenic heterogeneity and, in particular, evasion of the immune response. The presence of different tprK alleles in the tprK locus strongly suggests the existence of genetically different subpopulations within treponemal isolates.

Alleles↗
PubMed2000

Multiple alleles of Treponema pallidum repeat gene D in Treponema pallidum isolates.

Two new tprD alleles have been identified in Treponema pallidum: tprD2 is found in 7 of 12 T. pallidum subsp. pallidum isolates and 7 of 8 non-pallidum isolates, and tprD3 is found in one T. pallidum subsp. pertenue isolate. Antibodies against TprD2 are found in persons with syphilis, demonstrating that tprD2 is expressed during infection.

Alleles↗
PubMed2000

Determinants of leisure time physical activity in rural compared with urban older and ethnically diverse women in the United States.

STUDY OBJECTIVE: Determinants of leisure time physical activity (LTPA) in rural middle aged and older women of diverse racial and ethnic groups are not well understood. This study examined: (1) urban-rural differences in LTPA by sociodemographic factors, (2) urban-rural differences in LTPA determinants, and (3) the pattern of relations between LTPA determinants and LTPA. DESIGN: A modified version of the sampling plan of the Behavioral Risk Factor Surveillance Survey (BRFSS) was used. Zip codes were selected with 20% or more of each of the following race/ethnic groups: African American, American Indian/Alaskan Native (AI/AN), and Hispanic. A comparison group of white women were also surveyed using standard BRFSS techniques. PARTICIPANTS: Rural (n=1242) and urban (n=1096) women aged 40 years and older from the US Women's Determinants Study. MAIN RESULTS: Rural women, especially Southern and less educated women, were more sedentary than urban women. Rural women reported more personal barriers to LTPA, cited caregiving duties as their top barrier (compared with lack of time for urban women), and had greater body mass indices. Rural women were less likely to report sidewalks, streetlights, high crime, access to facilities, and frequently seeing others exercise in their neighbourhood. Multivariate correlates of sedentary behaviour in rural women were AI/AN and African American race, older age, less education, lack of enjoyable scenery, not frequently seeing others exercise, greater barriers, and less social support (p<0.05); and in urban women, older age, greater barriers, less social support (p<0.05), and less education (p<0.09). CONCLUSIONS: Rural and urban women seem to face different barriers and enablers to LTPA, and have a different pattern of determinants, thus providing useful information for designing more targeted interventions.

Adult↗
PubMed2000

[Analysis of the resonant frequency of the middle ear in otosclerosis].

Multifrequency tympanometry scans pressures and frequencies from 226 to 2000 Hz to analyze the resonant frequency of the middle ear, which determines the balance between stiffness and mass. We studied 143 patients (a total of 200 ears) diagnosed as otosclerosis at the E.N.T. Service of Santiago de Compostela University Hospital Complex, and 136 control subjects. The mean age of patients was 47.7 years; women were predominant (female/male ratio 2.25:1). The mean duration of the disease was 10.4 years. Using the Virtual model 310 tympanometer, we calculated the resonant frequency through the susceptance tympanogram, corresponding to the minimal frequency at which the central notch of the tympanograrn was equal to or less than the negative tail. The mean resonant frequency was 1230 Hz, the tympanometric amplitude was 88.32 daPa, and the admittance of the middle ear was 0.63 cc. We confirmed an increase in the resonant frequency in patients with otosclerosis compared with normal subjects (1132.33 Hz), and a decrease in the admittance of the middle ear. The relation between the two values was significant.

Acoustic Impedance Tests↗
PubMed1999

Creation of a functional S-nitrosylation site in vitro by single point mutation.

Here we show that in extrahepatic methionine adenosyltransferase replacement of a single amino acid (glycine 120) by cysteine is sufficient to create a functional nitric oxide binding site without affecting the kinetic properties of the enzyme. When wild-type and mutant methionine adenosyltransferase were incubated with S-nitrosoglutathione the activity of the wild-type remained unchanged whereas the activity of the mutant enzyme decreased markedly. The mutant enzyme was found to be S-nitrosylated upon incubation with the nitric oxide donor. Treatment of the S-nitrosylated mutant enzyme with glutathione removed most of the S-nitrosothiol groups and restored the activity to control values. In conclusion, our results suggest that functional S-nitrosylation sites can develop from existing structures without drastic or large-scale amino acid replacements.

Cysteine↗
PubMed1999

Methionine adenosyltransferase S-nitrosylation is regulated by the basic and acidic amino acids surrounding the target thiol.

S-Adenosylmethionine serves as the methyl donor for many biological methylation reactions and provides the propylamine group for the synthesis of polyamines. S-Adenosylmethionine is synthesized from methionine and ATP by the enzyme methionine adenosyltransferase. The cellular factors regulating S-adenosylmethionine synthesis have not been well defined. Here we show that in rat hepatocytes S-nitrosoglutathione monoethyl ester, a cell-permeable nitric oxide donor, markedly reduces cellular S-adenosylmethionine content via inactivation of methionine adenosyltransferase by S-nitrosylation. Removal of the nitric oxide donor from the incubation medium leads to the denitrosylation and reactivation of methionine adenosyltransferase and to the rapid recovery of cellular S-adenosylmethionine levels. Nitric oxide inactivates methionine adenosyltransferase via S-nitrosylation of cysteine 121. Replacement of the acidic (aspartate 355) or basic (arginine 357 and arginine 363) amino acids located in the vicinity of cysteine 121 by serine leads to a marked reduction in the ability of nitric oxide to S-nitrosylate and inactivate hepatic methionine adenosyltransferase. These results indicate that protein S-nitrosylation is regulated by the basic and acidic amino acids surrounding the target cysteine.

Amino Acids↗
PubMed1999

Altered formation of hemichannels and gap junction channels caused by C-terminal connexin-32 mutations.

Hexamers of connexins (Cxs) form hemichannels that dock tightly in series via their extracellular domains to give rise to gap junction channels. Here we examined the ability of a variety of C-terminal Cx32 mutations, most of which have been identified in X-linked Charcot-Marie-Tooth disease, to form hemichannels and to complete gap junction channels using the Xenopus oocyte system. First, we show that undocked wild-type Cx32 hemichannels at the plasma membrane can be detected as opening channels activated by depolarization. We have been able to estimate the efficiency of assembly of complete channels by measuring the time-dependent incorporation of preformed hemichannels into gap junction channels after cell-to-cell contact. These data offer strong evidence that hemichannels are the direct precursors of gap junction channels. Of 11 Cx32 mutants tested, a group of 5 mutations prevented the formation of functional hemichannels at the cell surface, whereas 4 mutations were fully able to form precursors but reduced the ability of hemichannels to assemble into complete channels, and 2 mutants formed channels normally. The data revealed that a minimum length of human Cx32 including the residue Arg-215 is required for the expression of hemichannels at the cell surface and that the efficiency of hemichannel incorporation into complete channels decreased gradually with the progressive shortening of the cytoplasmic C-terminal domain.

Animals↗
PubMed1999

Treponema pallidum major sheath protein homologue Tpr K is a target of opsonic antibody and the protective immune response.

We have identified a family of genes that code for targets for opsonic antibody and protective immunity in T. pallidum subspecies pallidum using two different approaches, subtraction hybridization and differential immunologic screening of a T. pallidum genomic library. Both approaches led to the identification of a polymorphic multicopy gene family with predicted amino acid homology to the major sheath protein of Treponema denticola. One of the members of this gene family, tpr K, codes for a protein that is predicted to have a cleavable signal peptide and be located in the outer membrane of the bacterium. Reverse transcription polymerase chain reaction analysis of T. pallidum reveals that Tpr K is preferentially transcribed in the Nichols strain of T. pallidum. Antibodies directed to purified recombinant variable domain of Tpr K can opsonize T. pallidum, Nichols strain, for phagocytosis, supporting the hypothesis that this portion of the protein is exposed at the surface of the treponeme. Immunization of rabbits with the purified recombinant variable domain of Tpr K provides significant protection against infection with the Nichols strain of T. pallidum. This gene family is hypothesized to be central to pathogenesis and immunity during syphilis infection.

Amino Acid Sequence↗
PubMed1999

Generation of null alleles for the functional analysis of six genes from the right arm of Saccharomyces cerevisiae chromosome II.

Using PCR-ligated long flanking homology cassettes, null alleles of six open reading frames (ORFs) from chromosome II have been created in Saccharomyces cerevisiae. Deletants were constructed in three genetic backgrounds: FY1679, W303 and CEN.PK2. Tetrad analysis of heterozygous deletants revealed that none of the ORFs is essential for vegetative growth. Basic phenotypic analysis of haploid deletants showed that deletion of the YBR283c ORF causes a slight growth defect at 30 degrees C and 37 degrees C on glycerol-complete, glucose-complete, and glucose-minimal media only in the FY1679 and W303 backgrounds. Transformation of these deletants with the corresponding cognate gene in a centromeric plasmid complements the defects. Deletion of the YBR287w ORF leads to poor growth on glucose-minimal medium at 15 degrees C in the FY 1679 background. None of the six ORFs seems to be involved in mating or sporulation.

Alleles↗