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Biomedical subjects

A Pineda

Publications and source records attributed to A Pineda.

At least 19 recordsLinked to original sources
PubMed2004

Increased mast cell density and protease content in actinic cheilitis.

BACKGROUND: Actinic cheilitis (AC) is a pre-malignant lesion caused by ultraviolet (UV) radiation and characterized by epithelial and connective tissue alterations. Mast cells (MCs), key contributors to solar elastosis in murine UV-irradiated skin, were characterized in order to assess their potential contribution to connective tissue degeneration in AC. METHODS: Actinic cheilitis (n = 15) and normal lip (n = 8) biopsies were stained immunohistochemically for tryptase and enzymehistochemically for chymase to determine MC density and protease content. MC subpopulations (i.e. MC(T) containing only tryptase, and MC(TC) containing chymase and tryptase) and their distribution were also determined. RESULTS: Mast cells and their proteases were increased in AC as compared with normal lip (P < 0.0001), and appeared degranulated especially around elastotic areas. MC(T) predominated over MC(TC) in AC and normal lip (P < 0.05). However, in AC MC(T) were increased in the epithelium/connective junction and connective area (P < 0.05), while in normal lip MC(T) predominated in connective and submucosal areas (P < 0.05). CONCLUSION: The results suggest that increased MC density and protease content may contribute to elastosis formation in AC. In addition, changes in MC(T) distribution may favor AC malignization.

Adult↗
PubMed2002

A set of simple-sequence repeat (SSR) markers covering the Prunus genome.

A set of 109 microsatellite primer pairs recently developed for peach and cherry have been studied in the almond x peach F(2) progeny previously used to construct a saturated Prunus map containing mainly restriction fragment length polymorphism markers. All but one gave amplification products, and 87 (80%) segregated in the progeny and detected 96 loci. The resulting Prunus map contains a total of 342 markers covering a total distance of 522 cM. The approximate position of nine additional simple sequence repeats (SSRs) was established by comparison with other almond and peach maps. SSRs were placed in all the eight linkage groups of this map, and their distribution was relatively even, providing a genome-wide coverage with an average density of 5.4 cM/SSR. Twenty-four single-locus SSRs, highly polymorphic in peach, and each falling within 24 evenly spaced approximately 25-cM regions covering the whole Prunus genome, are proposed as a 'genotyping set' useful as a reference for fingerprinting, pedigree and genetic analysis of this species.

Chromosome Mapping↗
PubMed1999

Arthritis in patients with chronic hepatitis C virus infection.

OBJECTIVE: To describe the clinical picture of arthritis in patients with chronic infection by hepatitis C virus (HCV). METHODS: Two patient populations were studied. Patients with arthritis and evidence of serum elevation of alanine aminotransferase (ALT) at the consultation were checked for HCV infection. A second group of 303 consecutive patients with rheumatoid arthritis (RA) were also checked for the presence of HCV antibodies. All patients attended the outpatient rheumatology unit of a tertiary care teaching hospital. Chronic HCV infection was determined by the presence of viral RNA in serum. A group of 315 first-time blood donors served as controls. RESULTS: Twenty-eight patients with arthritis and chronic HCV infection were identified. Seven fulfilled criteria for RA, psoriatic arthritis was found in one patient, systemic lupus erythematosus in one, gout in 2, chondrocalcinosis in 2, osteoarthritis in 7, and tenosynovitis in one. In 7 patients with a clinical picture of intermittent arthritis, a definitive diagnosis could not be made. In these patients, mixed cryoglobulinemia was present in 6/7 (86%), whereas mixed cryoglobulinemia was found in 6/21 (28%) of the other patients. Among patients with RA, 23 (7.6%) had HCV antibodies, and active infection by HCV was found in 7 (2.3%) patients. The prevalence of HCV antibodies in a blood donor population was 0.95%, significantly different (p<0.001; 95% CI 0.03, 0.10) compared to patients with RA. The distribution of antibodies determined by recombinant immunoblot analysis was similar (p = NS) between RA patients and blood donors with HCV antibodies. CONCLUSION: There is not a single clinical picture of arthritis in patients with chronic HCV infection. There is a well defined picture of arthritis associated with the presence of mixed cryoglobulinemia that consists of an intermittent, mono or oligoarticular, nondestructive arthritis affecting large and medium size joints. Although a high prevalence of HCV antibodies is suspected in patients with RA, its occurrence may be coincidental and its interpretation is difficult to determine from the data in this study.

Adult↗
PubMed1994

NMR solution structure of the isolated N-terminal fragment of protein-G B1 domain. Evidence of trifluoroethanol induced native-like beta-hairpin formation.

The solution structure of the isolated N-terminal fragment of streptococcal protein-G B1 domain has been investigated in H2O and TFE/H2O solution by CD and NMR to gain insight into the possible role that native beta-hairpin secondary structure elements may have in early protein folding steps. The fragment also has been studied under denaturing conditions (6 M urea), and the resulting NMR chemical shifts were used as a reference for the disordered state. On the basis of CD and NMR data, it is concluded that in aqueous solution the fragment is basically flexible, with two local low populated chain bends involving residues 8-9 and 14-15, respectively, in close agreement with secondary structure predictions, a structure that is different from the final folded state of that segment of the protein. The changes in the CD spectrum, the presence of several medium-range NOEs plus two long-range NOEs, and the sign of the H alpha conformational shifts reveal that the addition of TFE facilitates the formation of a set of transient beta-hairpins involving essentially the same residues that form the native beta-hairpin found in the final three-dimensional structure of the B1 domain. The stabilization of native-like structures by TFE is known to occur for helices, but, to our knowledge, this is the first time the stabilization of a native-like beta-hairpin structure by TFE is reported. Since long-range tertiary interactions are absent in the isolated fragment, our results support the idea that, in addition to helices, beta-hairpins may play an active role in directing the protein folding process.

Amino Acid Sequence↗
PubMed1994

Effects of 3-5 log10 pre-storage leucocyte depletion on red cell storage and metabolism.

A new, in-line high-efficiency 3-5 log10 leucodepletion filter system (Leukotrap RC system) was used to investigate the effect of pre-storage white cell removal on the quality of AS-3 red cell concentrates stored for 42 d at 4 degrees C. Median residual white cell content was 4 x 10(5) when filtration was performed at 22 degrees C within 8 h of phlebotomy (n = 20) and 3.2 x 10(4) when filtration was performed at 4 degrees C 12-24 h after phlebotomy (n = 24). None exceeded 1 x 10(6) WBC per red cell product. Filtration was rapid (median 28 min), and red cell loss averaged (mean +/- 1 SD) 6.4 +/- 0.7%. In a paired study design, post-transfusion recoveries of 42 d stored red cells in the filtered units averaged 84 +/- 6% v 82 +/- 8% for unfiltered units (P < 0.05) and post-storage haemolysis. ATP, osmotic fragility, K+ and pH were significantly (P < 0.05) better in the filtered units. Reduced glycolytic activity was also observed in the filtered units, and there was a correlation between osmotic fragility, glucose consumption, and lactate produced in standard units that was not present in leucodepleted units. In conclusion, this study suggests that leucodepletion of AS-3 red cell concentrates prior to storage results in better maintenance of the integrity of the red cell membrane with reduced glycolytic activity. There was a modest improvement in post-infusion viability sufficient to offset the filtration-induced loss and to result in an equivalent red cell product.

Adenosine Triphosphate↗
PubMed1986

Plasma exchange in chronic inflammatory demyelinating polyradiculoneuropathy.

Plasma exchange has been reported to be efficacious in chronic inflammatory demyelinating polyradiculoneuropathy. We performed a prospective double-blind trial in which patients with static or worsening disease were randomly assigned to plasma exchange (n = 15) or to sham exchange (n = 14) for three weeks. After three weeks, we observed statistically significant differences in combined measurements of nerve conduction (total, motor, proximal, velocity, and amplitude) favoring patients who had received plasma exchange. Improvement to a greater degree than for any patient receiving sham exchange was detected in the neurologic-disability score in five patients (P = 0.025) and in subset scores for weakness and reflex in four patients (P less than 0.057). We conclude that for some patients with chronic inflammatory demyelinating polyradiculoneuropathy, plasma exchange has an ameliorating effect on neurologic dysfunction and nerve conduction, but in others no improvement is observed. Because plasma was replaced with normal serum albumin, a humoral factor or factors may have a role in the neurologic deficit of this disorder.

Chronic Disease↗
PubMed1982

The Mayo Clinic experience with plasma exchange in chronic inflammatory-demyelinating polyneuropathy (CIDP).

Fourteen patients with static or progressive CIDP with a neurologic disability score (NDS) greater than or equal to 50 were entered into a double-blind, stratified, 3-week trial of twice-weekly plasma exchange or sham plasma exchange. The end-points evaluated included the NDS, computer assisted sensory examination of the foot, and various attributes of nerve conduction of motor and sensory fibers of limb nerves. Of the 7 patients receiving plasma exchange, 4 improved by more than 10 points on the NDS (45, 32, 11, and 24 points) while 3 remained unchanged (2, -2, and -3 points). One patient, who did not appear to respond to either sham or plasma exchange, improved (100 points) with a 3 month alternate day course of prednisone. Of the 7 patients on sham exchange, 3 improved by more than 10 points (26, 15, and 16), 3 remained unchanged (-5, 4, and 8) and 1 was not able to complete the study due to cardiac tamponade. This preliminary trial will end with acquisition of 30 patients. It is too early to draw any conclusion from these studies other than that the double-blind study employed here is feasible and should provide information on the efficacy of plasma exchange in CIDP if its effect is prompt and large. The improvement which may be seen in the sham group appears to suggest that studies of efficacy require a double-blind design.

Adult↗
PubMed1980

Determinants of fertility in Guatemala.

The 1978 Contraceptive Prevalence Survey for Guatemala provides an opportunity to examine fertility levels and a number of determinants of fertility for three broad segments of the country: the Department of Guatemala and, in the remainder of the country, the Ladino and Indian populations. While Ladinos had a much higher rate of contraceptive use than did Indians, the two groups had similar birth rates. The lack of difference in fertility appears to be due to the pattern of prolonged breastfeeding among Indians and perhaps to differences in the rate of conception due to nutrition, coital frequency, or other factors.

Adult↗
PubMed1978

Complications of dorsal column stimulation.

The complications associated with 92 dorsal column stimulator implants are reported. They were of two types, technical and functional. In all there were 58 significant complications. Most technical complications were correctable but complications difficult to correct occurred in 26 patients. Late failure in stimulation was observed in 32 implants that had given excellent pain control for periods ranging from months to years. Improvements in the results of this procedure may be achieved by future technical developments and by clarification of physiological mechanisms.

Electric Stimulation Therapy↗
PubMed1978

Metastasis to the vagina from carcinoma of the breast.

Carcinoma of the breast, metastatic to the ovary, is encountered frequently. The potential routes of dissemination include transcoelomic spread, lymphatic spread and vascular (arterial or venous) transportation. A case report of vaginal metastasis secondary to bilateral breast carcinoma is cited and the potential mechanisms for dissemination described.

Breast↗