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Biomedical subjects

M Peña

Publications and source records attributed to M Peña.

At least 37 records · Page 2Linked to original sources
PubMed1998

Takayasu arteritis in Colombia.

Takayasu arteritis has been recognized in Colombia just recently, and so far we do not have any report concerning its presentation here. In this first report, some issues related to the presentation of the disease are indicated and compared with those found in the medical literature. No differences were found in age and sex. Most of the cases were diagnosed during an inactive phase of the disease with advanced manifestations due to vascular lesion which suggests the existence of some genetic factor influencing such a presentation, or may be the consequence of a delay in diagnosing the disease during initial and active stages due to not suspecting it. Comparing the vessels which are affected among other races and countries, we can find both differences and similarities. With the purpose of discovering the demographic, clinical, angiographic and laboratorial characteristics of Takayasu arteritis in Colombia, the present study was carried out by studying 35 clinical cases in different medical centers of the country.

Adolescent↗
PubMed1998

Buerger's disease at the 'San Juan De Dios' Hospital, Santa Fe De Bogota, Colombia.

OBJECTIVES: To know the clinical characteristics in the presentation of Buerger's disease in San Juan de Dios Hospital, Bogota, Colombia, between 1986 and 1996, and compare them with a previous series from the same Hospital and another reported in international literature; To determine the changes in the form of appearance of the disease. METHODS: We reviewed the clinical information of 22 patients with diagnosis of Buerger's disease, observed between 1986 and 1993, and we added the information of the clinical histories of eight other patients with equal diagnosis, observed between 1994 and 1996 in our Unit. RESULTS: We observed 30 patients: 28 men (93%) and two women (7%), with a ratio M:F of 14:1, with an average age of 39+10 years (range from 18 to 52 years). Sixty percent were younger than 40 years and only the 10% were older than 50 years. The most frequent reasons for consultation were: pain in rest in the affected extremity, gangrene and ulceration in more than 50%. Raynaud's phenomenon in 30%, and the related surgical history in 40%. The pedal pulse was the most compromised followed by popliteal, poster or tibial and femoral. We did not observe the presence of thrombophlebitis. Eighty percent showed compromise of more than one extremity. All of them were active smokers. Three patients showed IgG anticardiolipine antibodies at high level. CONCLUSIONS: The clinical characteristics are similar to those reported, we find also a reduction of the disease diagnosis. It calls to our attention that no thrombophlebitis was found in the present series and the less compromise of the upper extremities with a frequent femoral compromise. All this points toward a change in the natural history of the disease.

Adolescent↗
PubMed1998

Structure of keratan sulfate from bonefish (Albula sp.) larvae deduced from NMR spectroscopy of keratanase-derived oligosaccharides.

Structural details of keratan sulfate (KS) glycosaminoglycan, isolated from early-metamorphosing larvae (leptocephali) of bonefish (Albula sp.), are described. Bonefish KS was analyzed by first hydrolyzing the purified compound with KS endo-beta-galactosidase (keratanase) from Pseudomonas spp., and then examining the resulting oligosaccharides with reversed-phase high-performance liquid chromatography (HPLC) and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy at 400 MHz. Spectral analyses were performed by COSY and HMQC. The results showed that a single oligosaccharide was produced whose structure is consistent with that of a tetrasaccharide containing two, beta-linked, N-acetyllactosamine units. Enzymic evidence indicated that the internal galactose of the tetrasaccharide was O-sulfated at C-6, and that the reducing-end galactose was unsulfated. Spectral data for C-1 of the two galactose residues were consistent with the proposed sulfation pattern. In addition, spectral evidence confirmed that a C-6 on one of the sugars was sulfated: this sulfate was tentatively assigned to the internal galactose. Chemical studies have shown that an additional sulfate group is present, but its assignment could not be confirmed, owing to the complexity of the spectral data. The known specificities of keratanase, and the production of a single tetrasaccharide, however, require that the additional sulfate reside on C-6 of either of the two available N-acetylglucosamine (GlcNAc) moieties, and that it cannot alternate between the two. The inability of beta-N-acetylglucosaminidase from beef kidney to liberate GlcNAc from the tetrasaccharide provided preliminary support for the view that this sulfate is located on the nonreducing-end GlcNAc. We conclude that the native, high molecular weight (M(r) = 55,000) KS polymer from bonefish larvae consists of a disulfated disaccharide alternating with an unsulfated disaccharide in the adjacent N-acetyllactosamine unit, with this pattern repeating itself in a regular fashion along most, or all, of the chain. This structure could provide an explanation for the ability of bonefish KS chains to self-associate into dimers. Although the N-acetyllactosamine repeat is characteristics of KS in general, the sulfation pattern is different from that postulated for the well-characterized KS chains of lower molecular weight obtained from mammalian cornea and cartilage. An additional difference was the inability to demonstrate sialic acid in bonefish KS.

Animals↗
PubMed1998

Phase II trial of cisplatin and gemcitabine in advanced squamous-cell carcinoma of the head and neck.

BACKGROUND: To evaluate the toxicity profile and efficacy of cisplatin combined with gemcitabine in patients with irresectable locally recurrent or metastatic squamous cell carcinoma of the head and neck. PATIENTS AND METHODS: Gemcitabine was given at a dose of 800 mg/m2 on days 1, 8 and 15, plus cisplatin at a dose of 50 mg/m2 on days 1 and 8; every four weeks. RESULTS: Twenty-four patients with a median age of 59 years (range 42-74) were included. All patients were evaluable for toxicity and 22 patients were assessable for response. Eleven cases had advanced recurrent locoregional disease while 13 patients had metastatic disease. One CR (4.7%) and four PR (18%) were observed, for an overall response rate of 22.7% (95% CI: 8%-42%). The main toxicity was hematological: neutropenia grade 3-4 in 28% of the cycles and thrombocytopenia grade 3-4 in 16%. The most significant non-hematological toxicity was asthenia grade 2-3 in 24% of the cycles. CONCLUSIONS: This cisplatin plus gemcitabine combination schedule has a favourable toxicity profile with a discrete activity in patients with locally recurrent or metastatic squamous-cell carcinoma of the head and neck.

Adult↗
PubMed1998

Help seeking for mental health care among poor Puerto Ricans: problem recognition, service use, and type of provider.

OBJECTIVES: This study examines the effects of health, predisposing, and enabling factors on recognition of a mental health problem, use of formal mental health care, and contact with a specialized mental health provider. METHODS: Interviews were conducted with a probability sample of 3,435 adults. The variables examined include measures of mental health; social and demographic factors; and enabling factors relevant to the help-seeking process. RESULTS: Subjective and objective measures of mental health were associated with the recognition of a mental health problem. The objective assessment of definite need for services was relevant for the use of formal services. However, the subjects' perception of poor mental health was strongly related to receiving care from a mental health specialist. Although interaction with social networks is associated with use of formal services, low economic strain is related to receiving care from the specialty sector. CONCLUSIONS: The results support the importance of using multiple measures of mental health problems. The finding that individuals' perceived economic strain increases the likelihood of receiving specialized care suggests that studies of economic barriers to the use of mental health services might benefit from the adoption of measures that assess perceived economic circumstances.

Adolescent↗
PubMed1998

Myocardial collagen in cardiac hypertrophy resulting from chronic aortic regurgitation.

Myocardial fibrosis and abnormal myocardial collagen content are common in many forms of pathological cardiac hypertrophy, including that mediated by pressure overload. Recently, in an experimental animal model of chronic aortic regurgitation (AR), we found a strong relation between myocardial fibrosis and congestive heart failure development. To determine if these fibrotic lesions are composed of collagen, as they are in pressure overload, and to determine if potential preventive therapies should be developed similarly in both diseases, we assessed left ventricular collagen content at three time points after AR induction. Moderate to severe AR was induced in 19 New Zealand White rabbits by inserting a catheter through the carotid artery to perforate the aortic valve leaflets. Animals were killed (1) when they showed echocardiographically discernible systolic dysfunction or (2) if normal cardiac function continued, either early (1 month) or late (>3 years) after operation. Fourteen age-matched, sham-operated controls and seven normal unoperated rabbits also were studied. Collagen concentrations were determined biochemically by hydroxyproline measurement. Fibrosis was measured histologically using Mason's trichrome stain and the fibrous collagen-specific stain, Picro-Sirius Red. Our results show an age-related increase in left ventricular collagen concentration with no specific increase among animals with evidence of fibrosis. We conclude that, unlike pressure overload, volume overload produces fibrotic lesions not composed predominantly of excess collagen and that the therapy needed to prevent fibrosis may be different in these conditions. Further study is needed to define the chemical characteristics of the fibrous lesions and the pathophysiological importance of this finding.

Age Factors↗
PubMed1997

Mental health utilization in women with symptoms of depression.

This paper examines the help-seeking process of mental health services in women with high depressive symptoms. The data are based on an island wide probabilistic sample (n = 1,062) of 18- to 64-year-old women living in low socioeconomic areas in Puerto Rico. Symptoms of depression were measured by the Center for Epidemiological Studies Depression Scale (CES-D). Results show that one out of three women living in poor residential areas report high depressive symptoms. Of these women with high depressive symptoms, only 12% seek help from a mental health specialist and 14.5% from a general health care provider to deal with their emotional problems. Some factors related to the use of mental health services are: presence of an occupational disability, head of household status, having private insurance, and having a regular source of care. These data suggest that women underutilize mental health services and overutilize physical health services to deal with their emotional problems. The lack of recognition of emotional problems by these women may explain the low utilization of mental health services.

Adolescent↗
PubMed1997

Study of escalating doses of paclitaxel plus cisplatin in patients with inoperable head and neck cancer.

This phase I/II study sought to determine the response rate and toxicity profile of escalating doses of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) when administered with fixed doses of cisplatin with granulocyte colony-stimulating factor support in 28 patients with head or neck cancer. The study was designed as a modified dose-finding trial and contained five dose-escalation levels of paclitaxel. Dose level 1 contained seven patients, and doses ranged from 175 to 220 mg/m2; dose level 2, 230 to 250 mg/m2 (five patients); dose level 3, 250 mg/m2 only (four patients); dose level 4, 260 to 280 mg/m2 (six patients); and dose level 5, 280 to 300 mg/m2 (six patients). Dose levels greater than 200 mg/m2 were supported with concomitant granulocyte colony-stimulating support. Paclitaxel was given on day 1 by 3-hour infusion; cisplatin 75 mg/m2 was given on day 2. Courses were given every 3 weeks. All patients were evaluable for toxicity and 27 were evaluable for response. The overall response rate was 77% (10 complete responses, 11 partial responses, four no change, and two disease progression). Over a median follow-up of 15 months (range, 7 to 22 months), 16 patients showed no evidence of disease and three are alive with disease. A dose-effect relationship was found between paclitaxel and peripheral neuropathy. Twenty-seven of 28 patients experienced alopecia, peripheral neuropathy, myalgias, and arthralgias. Most toxicities were grade 1 or 2; the mean duration of symptoms was 7 days. No dose-limiting hematologic toxicity was observed, nor was any significant neutropenia seen in those patients receiving filgrastim. The paclitaxel/cisplatin combination was found to be an effective first-line regimen for patients with head or neck cancer. Although the number of patients in this study was small, no relationship was noted between patient response and disease site.

Adult↗
PubMed1997

Phase I/II study of paclitaxel/cisplatin as first-line therapy for locally advanced head and neck cancer.

A phase I/II study was conducted to determine the response rate and the toxicity of escalating doses of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) plus cisplatin with granulocyte colony-stimulating factor support in patients with untreated advanced head and neck carcinoma. Twenty-eight patients with locally advanced inoperable squamous cell head and neck carcinoma were included. Median age was 51 years. Karnofsky performance status was > or =90% in all patients. Primary tumor sites were oropharynx, hypopharynx, larynx, oral cavity, parotid gland, nasal cavity, and unknown primary. We observed 13 complete responses, eight partial responses, four patients with stable disease, and two patients with progressive disease for an overall response rate of 78%. Toxicity was paresthesia grade 1/2 in 27 patients, and myalgias were grade 1/2 in 23 patients and grade 3 in four patients. One patient died 5 days after the first cycle due to acute renal failure, respiratory distress, and pancytopenia. No dose-limiting hematologic toxicity has been observed, and intrapatient escalations were performed in all patients when planned. Calculated dose intensity for the two drugs was 100% in all evaluable patients. The combination of escalating doses of paclitaxel 175 to 300 mg/m2 and cisplatin 75 mg/m2 was active in untreated head and neck carcinoma, with an overall response rate of 78%. No dose-limiting toxicity has been encountered at paclitaxel doses up to 300 mg/m2 given with granulocyte colony-stimulating factor.

Adolescent↗
PubMed1996

Gout nodulosis: widespread subcutaneous deposits without gout.

Subcutaneous tophaceous deposits of monosodium urate, in the absence of arthritis, may occasionally occur as the initial manifestation of gout. In this report, we describe a 35-year-old man who presented with a 6-year history of multiple subcutaneous nodules and no history of previous articular complaints. Needle aspirations of the nodules proved them to be deposits of monosodium urate. A literature search revealed 28 other cases with a similar presentation. We propose the term "gout nodulosis" as a clinical entity at one end of the spectrum of gout to describe this group of patients.

Adult↗
PubMed1996

The prevalence of anthelmintic resistance in nematode parasites of sheep in southern Latin America: Argentina.

Sixty-five sheep farms in the northern provinces of Buenos Aires, Entre Rios, Corrientes, Cordoba and Sante Fe were used in this survey on anthelmintic resistance. Anthelmintic groups tested were the benzimidazoles, levamisole, the combination levamisole + benzimidazole product and the avermectins. The overall level of resistance was 46% of properties, with resistance to the individual drug groups being 40%, 22%, 11% and 6%, respectively. On a large proportion of farms the resistance recorded was to two, or more, anthelmintic groups. Haemonchus contortus, Ostertagia spp. and Trichostrongylus spp. were the most abundant parasite species recorded. Resistance was greatest in the province of Corrientes where the frequency of treatment is generally high due to the endemic nature of H. contortus. Management practices were also important with resistance greatest on farms where frequent drenching is carried out and on farms carrying only sheep.

Agriculture↗
PubMed1996

[Severe cardiac failure as complication of primary hypothyroidism].

We report a 29 years old female admitted due to a congestive cardiac failure that failed to respond to therapy with furosemide and enalapril. Serum thyroid hormone profile showed a TSH over 40 microIU/ml, a thyroxine of 0.8 microgram/dl and a triiodothyronine below 20 ng/dl. Levothyroxine therapy was started with remission of cardiac failure. The study of thyroid function in patients with cardiac failure of unknown origin and resistant to therapy, should be bone in mind.

Adult↗
PubMed1995

Characterization of B27 haplotypes by oligotyping and genomic sequencing in the Mexican Mestizo population with ankylosing spondylitis: juvenile and adult onset.

The aim of this study was to investigate the contribution of the different B27 subtypes in the Mexican Mestizo population with juvenile and adult AS. No differences in the distribution of B27 subtypes were found between both populations, B*2705 being the predominant subtype followed by B*2702. Transracial gene mapping was performed in order to find out the origin of the B27 alleles of the Mexican Mestizos. A PCR with SSOPs was used to analyze the polymorphism in exons 2 and 3 of HLA-B27 and HLA-C related alleles. This population shares with the Spanish Caucasians B*2705 and B*2702, which are absent in Central and South American Indians. AS and healthy Mexican mestizo donors were analyzed to ascertain B27/Cw haplotypes. The B27/Cw linkage arrangements seen in mestizos are similar to those reported for Caucasian Spaniards with three different haplotypes positively associated with AS in both populations, B*2705/Cw*0102, B*2705/Cw*02022, and B*2702/Cw*02022, suggesting that B27 in Mexicans may be due to a recent Caucasoid admixture with the Spanish genes. Finally, a strategy for sequence analysis of exons 2 and 3 from genomic DNA of HLA-B27 alleles was developed. A novel HLA-B27-like allele typed serologically as B27 was identified and sequenced by this method in a healthy Mexican mestizo, corresponding to the B*7301 variant found with low frequency in different populations. Analysis of the association of B*7301 to AS would require an extensive study in different populations and could provide insights into the molecular structure of the alleles involved in the disease.

Adolescent↗
PubMed1995

The anatomical substrates for language and hemispheric specialization.

Three main lines of investigation are discussed in this paper: (1) the comparison between the anatomical arrangement of the language areas and the large-scale neurocognitive cortical networks partly involved in active or working memory; (2) the relations between hemispheric specialization and the development of interhemispheric communication; and (3) the analysis of individual differences in brain organization for language. The hypothesis and evidence presented stem from work being performed in our laboratories.

Cerebral Cortex↗
PubMed1994

Molecular analysis of HLA-B27 haplotypes in Caucasoids. Frequencies of B27-Cw in Jewish and Spanish populations.

PCR in combination with SSO probes was used to analyze the polymorphism in exons 2 and 3 of HLA-B27 subtypes and HLA-C-related alleles in two genetically distant Caucasian groups: Spanish and Jewish populations. AS patients and healthy B27 donors from both populations were analyzed in order to ascertain B27-Cw haplotypes. Three different ancestral haplotypes were found to be represented in both populations: B*2705/Cw*0102, B*2705/Cw*02022, and B*2702/Cw*02022. The B*2705 (92.5%) was the most frequent allele found in the Spanish population, carried by B*2705/Cw*0102 (60.9%) and B2705/Cw*02022 (30.4%) haplotypes. In contrast, B*2702 (59.4%) was the most prevalent allele found in the Jewish population and was carried by the B*2702/Cw*02022 (63.3%) haplotype. No different allelic and haplotypic distributions were among healthy and AS patients in either Spanish or Jewish populations. The differences found in the distribution of B27 haplotypes among Spanish and Jewish Caucasian populations are consistent with the genetic distance of these ethnic groups. When the Jewish population was subdivided into Ashkenazi (A) and non-Ashkenazi (NA) groups, no significant differences were observed in the distribution of B*2702/Cw*02022 haplotype. Minor differences were observed in the underrepresented B*2705 haplotypes. The present results reflect the ancestral affinities of A and NA Jewish populations. A possible HLA-B27 evolutive pathway in Caucasians is proposed according to the data available for the B27/Cw ancestral haplotypes in Spanish and Jewish groups.

Base Sequence↗
PubMed1994

[Primary cytomegalovirus infection in pregnant women of different socioeconomic status].

Cytomegalovirus infection is the first cause of viral congenital infections. We studied the incidence of primary cytomegalovirus infection, searching for the presence of antibodies with an ELISA technique, in 939 pregnant women of a low socioeconomic level, attending a public outpatient clinic and 123 pregnant university students, attending a special outpatient clinic for students. The initially seronegative women were tested again during the second and third trimester of pregnancy to identify primary infections. The presence of cytomegalovirus congenital infection in the newborns of infected mothers was investigated isolating the virus in cell cultures from urine samples. There was a higher prevalence of infection among low socioeconomic status women (95 vs 69.9%). Two women (one student and one coming from a low socioeconomic status) had a primary infection and in the newborn of the student, a congenital cytomegalovirus infection was detected. It is concluded that women's socioeconomic condition is not a risk factor for cytomegalovirus primary infection during pregnancy.

Adult↗