Search PubMed⌕ Search

Biomedical subjects

A Marin

Publications and source records attributed to A Marin.

At least 19 recordsLinked to original sources
PubMed2003

Analysis of risk factors for acute cutaneous graft-versus-host disease after allogeneic stem cell transplantation.

BACKGROUND: Although skin is typically the first site of involvement of acute graft-versus-host disease (GVHD), most standard recommended staging and grading criteria allow enrolment of patients with involvement of GVHD target organs other than the skin in studies analysing risk factors for acute GVHD after stem cell transplantation (SCT). OBJECTIVES: To determine the risk factors for developing histologically confirmed acute cutaneous GVHD in patients who underwent allogeneic SCT for different haematological disorders. METHODS: This retrospective study was based on review of clinical files and databases from 300 consecutive patients with several haematological disorders who received allogeneic SCT between 1 January 1984 and 31 December 1999 at Hospital Universitario de la Princesa, Madrid, Spain. Variables evaluated included diagnosis of haematological disorder, age and gender (donor and recipient), HLA matching, female donor to male recipient, donor and recipient viral serology (cytomegalovirus), conditioning regimen, GVHD prophylaxis, blood counts at day of engraftment, mortality, cause of death, and survival at 100 days, 5 years and 10 years following SCT. RESULTS: In multivariate analysis, risk factors for acute cutaneous GVHD were type of haematological disease (P = 0.006), HLA disparity (P = 0.006), number of transplants per patient (P = 0.017), conditioning regimen (P = 0.001), and GVHD prophylaxis (P = 0.025). Survival rates did not differ significantly for cases and controls. CONCLUSIONS: Risk factors for acute cutaneous GVHD were a diagnosis of chronic myeloid leukaemia, HLA disparity, receipt of more than one SCT, conditioning regimens including total body irradiation, and GVHD prophylaxis regimens other than ciclosporin plus methotrexate. Other common risk factors for acute GVHD without specific target organ involvement showed no significant association with the risk for developing acute GVHD affecting the skin as primary target organ.

Acute Disease↗
PubMed2001

Mechanism of the ultrasonic activation of micellar drug delivery.

The mechanism of the ultrasonic enhancement of the uptake of cytotoxic drugs, doxorubicin (DOX) and ruboxyl (Rb) by HL-60 cells from Pluronic micelles was studied. DOX and Rb sorption from either PBS or micellar Pluronic solutions is described by Langmuir-type isotherms characteristic of substrates with limited number of sorption centers. The sorption limits for Rb from PBS and Pluronic were considerably higher than those for DOX, presumably due to much higher Rb partitioning into cell membranes. The overall number of drug sorption centers for both drugs decreased in the presence of Pluronic implying the effect of Pluronic on the DNA conformation, which was confirmed by the electron paramagnetic resonance (EPR) experiments using Rb as a spin probe. Ultrasound increased drug uptake by the cells from PBS and Pluronic solutions. The fluorescence microscopy and flow cytometry experiments using fluorescently-labeled Pluronic showed that ultrasound enhanced both the intracellular uptake of Pluronic micelles and Pluronic trafficking into cell nuclei. A scheme is suggested that describes various equilibria controlling drug/cell interactions and effect of ultrasound on these equilibria. Under the action of ultrasound, the equilibrium between the micellar-encapsulated and free drug is shifted in the direction of free drug due to micelle perturbation; the equilibrium between extracellular and internalized drug is shifted to the intracellular drug due to the ultrasound-induced cellular changes that enhance the accessibility of various cellular structures to drug. An important advantage offered by ultrasound is that the same degree of the intracellular drug uptake may be achieved at a substantially lower drug concentration in the incubation medium.

Algorithms↗
PubMed2001

Acoustic activation of drug delivery from polymeric micelles: effect of pulsed ultrasound.

The effect of a continuous wave (CW) and pulsed 20-kHz ultrasound on the Doxorubicin (DOX) uptake by HL-60 cells from the phosphate buffered saline solution (PBS) and Pluronic micellar solutions was studied. Both CW and pulsed ultrasound enhanced DOX uptake from PBS and Pluronic micelles. The main factor that effected drug uptake was ultrasound power density; however, with increasing power, the enhanced drug uptake was accompanied by the extensive cell sonolysis. For PBS, no significant effect of duration of the ultrasound pulse or inter-pulse interval on the drug uptake was observed. For Pluronic micelles, the uptake increased with increasing pulse duration in the range 0.1-2 s, overall sonication time being the same. For 2-s pulses, the uptake was close to that under CW ultrasound. There was no significant effect of the duration of the inter-pulse interval on the drug uptake from Pluronic micelles. The data on the effect of pulse duration on drug uptake suggest that the characteristic times of drug release from micelles and drug uptake by the cells are comparable. The results point to two independent mechanisms controlling acoustic activation of drug uptake from Pluronic micelles. Both mechanisms work in concert. The first one is related to the acoustically-triggered drug release from micelles that results in higher concentration of the free drug in the incubation medium. The second mechanism is based on the perturbation of cell membranes that results in the increased uptake of the micellar-encapsulated drug. The intracellular uptake of Pluronic micelles was confirmed by fluorescence microscopy.

Antibiotics, Antineoplastic↗
PubMed2001

Molecular cloning of newt prolactin (PRL) cDNA: effect of temperature on PRL mRNA expression.

A partial prolactin (PRL) cDNA was specifically PCR amplified from a cDNA library constructed from pituitary mRNAs of the newt (Cynops pyrrhogaster) and cloned into plasmid vectors. One clone thus obtained contained a 739-bp insert encoding the C-terminal amino acid sequence of the mature hormone molecule. Using this clone as a probe, the full-length newt PRL cDNA was screened from the cDNA library. The PRL cDNA clone thus obtained consisted of 1024 bp encoding the entire sequence of the mature PRL molecule in addition to its signal peptide. The amino acid sequence of newt PRL deduced from its nucleotide sequence showed higher homologies with those PRL sequences of tetrapod animals than with those of teleosts. Northern blot analysis revealed the newt PRL mRNA size to be approximately 1 kb. In situ hybridization using the newt PRL cDNA as a probe revealed that the pituitary region expressing PRL mRNA corresponded to that immunoreactive with antiserum against PRL. PRL mRNA levels in the pituitary of newts subjected to room and low temperatures were determined by Northern analysis employing the PRL cDNA as a probe. PRL mRNA levels were significantly higher in the pituitaries of newts subjected to 10 degrees than in those of newts kept at 23 degrees. Likewise, immunoassayable plasma PRL levels were higher in animals subjected to 10 degrees than in those kept at 23 degrees.

Amino Acid Sequence↗
PubMed2001

Circadian rhythmicity of whole-blood glutathione in healthy subjects.

OBJECTIVES: Physiologic rhythms of antioxidants have been the subject of considerable interest in recent years. Physiologically, it is known that 24-h variability in whole-blood glutathione (GSH) could depend on various factors, such as meal composition, protein dietary content, meal-related hormonal modifications, and stress. Experiments were conducted to determine if the circadian variations previously observed in hepatic concentrations of reduced glutathione in animals also occurred in healthy volunteers. METHODS: The circadian periodicity of whole-blood glutathione was explored. All parameters were measured enzymatically at 4-h intervals over a 24-h period. RESULTS: Circadian rhythms were not found. The rhythms peak for glutathione content occurred at 9 h with a small peak at 21 h. The nadir occurred at 17 h and 1 h. CONCLUSION: These data show that despite this wide distribution of glutathione throughout the day we could not find any significant intertime variability.

Adult↗
PubMed2001

Practical implications of nutritional support during continuous renal replacement therapy.

Continuous blood membrane interactions during continuous renal replacement therapy cause bioincompatibility and low grade inflammatory reactions with potentially adverse consequences on protein metabolism and immunocompetence. In designing a nutritional program for patients receiving this treatment, these adverse metabolic effects, especially the loss of nutritional substrates, must be considered. This review provides a practical overview of nutritional support in acute renal failure, including assessment techniques, determination of nutrient needs, and appropriate intervention for patient support.

Acute Kidney Injury↗
PubMed2000

Protein domain interfaces: characterization and comparison with oligomeric protein interfaces.

The physical and chemical properties of domain-domain interactions have been analysed in two-domain proteins selected from the protein classification, CATH. The two-domain structures were divided into those derived from (i) monomeric proteins, or (ii) oligomeric or complexed proteins. The size, polarity, hydrogen bonding and packing of the intra-chain domain interface were calculated for both sets of two-domain structures. The results were compared with inter-chain interface parameters from permanent and non-obligate protein-protein complexes. In general, the intra-chain domain and inter-chain interfaces were remarkably similar. Many of the intra-chain interface properties are intermediate between those calculated for permanent and non-obligate inter-chain complexes. Residue interface propensities were also found to be very similar, with hydrophobic residues playing a major role, together with positively charged arginine residues. In addition, the residue composition of the domain interfaces were found to be more comparable with domain surfaces than domain cores. The implications of these results for domain swapping and protein folding are discussed.

Amino Acids↗
PubMed2000

[Color Doppler and ultrasound-guided prostate biopsy in the diagnosis of prostatic neoplasm].

The diagnosis of prostate neoplasm is still limited today by the variable power of prediction of the three main surveys used: prostate-specific antigen (PSA), digito rectal exploration (DRE) and ultrasound transrectal (TRUS). The study aimed to estimate the benefits and the diagnostic impact of the color Doppler ultrasonography on the diagnosis of prostate neoplasm through biopsies targeted on areas with abnormal flow. With this purpose, 222 biopsies performed on 71 patients between 1997 and 1999 were considered, which led to a diagnosis of neoplasm in 36 patients. Of the 84 biopsies that revealed prostate adenocarcinoma, 74 (64.3%) were correlated to hypoechoic lesions with abnormal flow signals while 41 (35.6%) showed a benign pathology (prostatitis or benign prostatic hyperplasia) (p < 0.0011). In five patients (13%) who did not present any evident lesions at a first transrectal ultrasound, the diagnosis of neoplasm was made only through biopsies targeted on areas with abnormal flow. Therefore, the color Doppler exam can be used during prostate ultrasonography either to consolidate the diagnosis or to give a useful target in case of isoechoic lesions.

Adenocarcinoma↗
PubMed1999

Parietaria allergy in children.

Parietaria, a grassy plant belonging to the Urticaceae family which is commonly found in urban environments, tends to grow on fences, walls and soils with a high content in nitrogen. Since 1983 the Xarxa Aerobiologica de Catalunya (Catalonian Aerobiological Network) has been using Hirst and Court sensors to monitor the daily concentrations of its pollen with respect to the weather conditions (wind, rain, temperature) in various sites in Catalonia and the Balearic Islands. This pollen is present practically all year round in our area, mainly during cold, rainy and seaside areas. Studies at a pediatric level are scarce and this is why we reviewed our data in this field. The study included a total of 12,650 case histories of first time attendances to our Pediatric Allergology Unit; 449 children showed sensitivity to Parietal pollen. Exclusive sensitivity to Parietaria in this age group of 1 and 15 years olds tended to be very low. However, we observed that after initial preferential sensitization to domestic allergens, Parietal pollen became the most frequent cause of sensitivity as the patients grew older. Although rhinoconjunctival manifestations predominate, at least at a pediatric level, the implication of Parietal pollen as a cause of bronchial asthma cannot be ignored.

Adolescent↗
PubMed1998

Allergy to pine nuts in children.

BACKGROUND: Allergy to nuts is a common and well-known disease. Despite the fact that pine nut is a widely eaten food, only nine cases have been described in literature. OBJECTIVE: To describe four paediatric patients suffering from allergy reaction on ingestion of pine nuts and compare them with cases described in literature, taking into account clinical symptoms, epidemiological and diagnostic methods. METHODS: The immuno-allergic study was carried out with skin tests (prick tests) using a commercial and native extract, and specific IgE serum test. An oral provocation test was performed in one case. RESULTS: Ages ranged from 12 months to 6 years. All patients had a personal history of atopy. Symptoms on ingesting pine nut were severe systemic reactions in three cases. Two of the children had allergic reactions to other nuts. In all cases, both the skin test and the specific IgE serum test were positive. The oral provocation was positive in the case for which it was performed. CONCLUSIONS: A typical clinical reaction of immediate hypersensitivity to this nut took place in all four children. The skin tests and in vitro studies confirm an IgE-mediated response. We currently have a commercial prick test for pine nut for the diagnosis, which has proven its sensitivity and specificity. In our region, due to the large consumption, the rate of allergic reactions to pine nuts would probably be greater and earlier on in life than in other areas.

Allergens↗
PubMed1997

The carboxy-terminus of I kappaB alpha determines susceptibility to degradation by the catalytic core of the proteasome.

The Rel/NF-kappaB family of transcription factors controls the expression of a wide variety of genes that are implicated in immune and inflammatory responses and cellular proliferation. Disregulation of NF-kappaB is associated with cellular transformation and the maintenance of a high anti-apoptotic threshold in transformed cells. NF-kappaB activity is in turn regulated by its sequestration in the cytoplasm by the inhibitor I kappaB. I kappaB alpha, the most abundant and well-characterized member of the I kappaB multiprotein family, is rapidly degraded in response to multiple physiologic stimuli. In the present study we show that not only the amino-terminus, but also the carboxy-terminus of I kappaB alpha contain transferable signals that must be simultaneously present in an unrelated protein to render it susceptible to activation-induced, proteasome-mediated degradation. We show here that I kappaB alpha amino-terminal modifications occur independently of the carboxy-terminus. Moreover, we present evidence indicating a critical role for the carboxy-terminal region in facilitating proteolysis by the catalytic core of the proteasome. When incubated with 20S proteasome extracted from rat liver, I kappaB alpha was quickly degraded while a deletion mutant lacking the carboxy-terminus was resistant to proteolysis. Likewise, chimeric proteins of beta-galactosidase with the I kappaB alpha carboxy-terminus were degraded in vitro independently of the presence of the I kappaB alpha amino-terminus, whereas chimeric proteins lacking the I kappaB alpha carboxy-terminus were stable. Our results identify the carboxy-terminus of I kappaB alpha as a domain critical for degradation through interaction with an as yet unidentified component of the proteasome.

Animals↗
PubMed1997

Electrophysiology and pharmacology of outward potassium currents in semicircular canal hair cells of toadfish, Opsanus tau.

Outward currents from hair cells from the horizontal semicircular canal (HSCC) of the toadfish were investigated using whole cell patch clamp methods. Two classes of hair cells are found. One class (approx. 10% of cells) showed only a non-inactivating current (IKCa) which was blocked by 2 mM TEA. A second class had both inactivating and non-inactivating currents. The former (IA) was blocked by 4-AP (1 mM) and the latter (IKCa) by TEA (2-20 mM) . While the majority of the cells expressed both these outward currents, due to IA inactivation both currents are functionally present in the same cell only between -60 and -40 mV. At more depolarized membrane potentials, IA was inactivated, suggesting that a single hair cell may have two distinct signalling modes, one dominated by IA at more hyperpolarized membrane potentials and the other by IKCa at depolarized values where ICa is beginning to grow, increasing both amplitude and activation rate of IKCa. The switch between modes will be determined by the amplitude and frequency characteristics of the stimulus and possibly also by actions of efferent transmitters. In current clamp mode, 10% of the HSCC hair cells showed high Q and high frequency resonance, from 44 to 360 Hz at 12 degrees C. These cells expressed only one outward calcium dependent, non-inactivating, TEA sensitive current, characteristic of IKCa. A suggested role for high frequency resonance is as positive feedback to produce a high frequency updating of the stereociliary compliance to most faithfully transduce angular acceleration.

4-Aminopyridine↗
PubMed1996

Physiological aging and penile erectile function: a study in the rat.

Erectile function of adult (8-month-old) and aged (27-month-old) rats was investigated by in vivo and in vitro assays. Reflexogenic tonic erections were evoked in vivo by electrostimulation of the dorsal nerve of the penis. Aged rats developed tendentially low intracavernosal pressures, and the kinetics of erection and detumescence were significantly lower than in adult animals. The erectile tissue isolated from aged rats exhibited poor response to papaverine. When precontracted with norepinephrine, aged tissues required a 3-fold increase of papaverine concentration to full relaxation. Functional measurements were coupled with morphological analysis of elastic fibres of the tunica albuginea. Light microscopy showed degenerative signs of elastic fibres of aged rat specimens. Taken together, the present findings show that physiological aging is associated with penile tissue stiffness and abnormal corporal compliance.

Aging↗
PubMed1996

[Ebastine : treatment of perennial rhinitis in the child].

Ebastine is H1 receptor antagonist, powerful and selective for histamine. Its efficacy has been evaluated in control of symptoms of persistent rhinitis, appearance of secondary effects and tolerance of the drug, in 30 children who were suffering from persistent rhinitis, of which the diagnosis included:- clinical history, skin tests (prick test) nasal and conjunctival provocation tests, total and specific IgE. All the children had treatment for 30 days. The parameters followed were:- clinical score, skin tests, nasal and conjunctival provocations and evaluation of secondary effects, of the start and 10 days after the end of treatment. The results obtained were a disappearance or reduction of the weals from histamine and specific antigens, disappearance or reduction of the response in nasal and conjunctival provocation with carbachol or specific antigens, clear clinical improvement in 22 patients, in 2 small improvement and no response in 6 patients. We conclude that Ebastine improved the clinical symptoms in persistent rhinitis, the skin test is inhibited and sensitivity of the shock organ is reduced. No secondary effects were seen on the Central Nervous System (SNC) and the tolerance of the drug was very good.

Adolescent↗
PubMed1995

Correlations between the clinical picture and the intentionality in schizophrenic and schizoaffective patients.

The results are presented of catamnestic research on 24 patients with the diagnosis of schizophrenia at the first clinical episode confirmed according to the ICD-10 criteria. The clinical picture rated with the Positive and Negative Symptoms Scale (Kay, Fiszbein and Opler, 1987) and with the BPRS, was correlated with the intentionality, which was rated with the InSka (IntentionalitätsSkala; Mundt, 1985). The transformation of the phenomenal significance into a numeric value enables the use of mathematical methods for the search of interactions inside the schizophrenic phenomenon. We found the following significant tendencies: (1) the negative syndrome score correlates with the residual intentionality; (2) the negative syndrome score correlates with the premorbid intentionality; (3) the clinical thought disturbance correlates with the premorbid speech content intentional profile.

Adult↗