Biomedical subjects

A Arellano

Publications and source records attributed to A Arellano.

At least 19 recordsLinked to original sources

PubMed2002

Use of 201Tl SPECT imaging to assess the response to therapy in patients with high grade gliomas.

PURPOSE: To assess the potential role of 201Tl single photon emission tomography (201-Thallium SPECT) when compared to other imaging modalities in the evaluation of the response to therapy in high grade gliomas. MATERIALS AND METHODS: Twenty patients with histologically proved high grade glioma have been included: 15 with glioblastoma (GBM), 3 with anaplastic astrocytoma (AA) and 2 with anaplastic oligoastrocytoma (AOA). Patients were assessed by 201Tl SPECT, computed tomography (CT) and magnetic resonance imaging (MRI) at (a) either at the moment of maximum response to first line chemotherapy, or after the completion of radiotherapy and chemotherapy if post-surgical residual disease was present, and (b) after the completion of second line chemotherapy if disease persisted, or either a relapse or disease progression was confirmed. Final response was evaluated according to the McDonald criteria, and by comparing SPECT, CT and MRI results. RESULTS: According to the McDonald criteria, clinical response after first line chemotherapy was 5 partial response, 7 stable disease and 8 progressive disease. Evaluation by 201Tl SPECT was in agreement with such criteria in nearly all patients (90%). MRI findings closely agreed with the clinical follow-up. CT findings clearly differed from those observed by SPECT and MRI. After second line therapy, 10 patients progressed, 3 had stable disease and 7 had partial response. 201Tl SPECT agreed with the clinical status in 89% cases, whereas MRI and, specially CT, fared significantly lower. CONCLUSION: Compared to conventional neuroimaging, 201Tl SPECT added valuable information in the assessment of the response to therapy in our patient population; whenever findings were not conclusive and in the case of disagreement between CT and MRI findings.

Adult↗

PubMed2001

Combined effect of oleic acid and propylene glycol on the percutaneous penetration of tenoxicam and its retention in the skin.

The influence of oleic acid (OA) on the in vitro percutaneous absorption of tenoxicam (TEN) and its combined effect with propylene glycol (PG) was studied using Franz-type diffusion cells. Furthermore, at defined concentrations of OA, complexes of the drug with cyclodextrins (MbetaCD and gammaCD) were added because their combined use may be an interesting approach to raise TEN flux. In addition, the amount of TEN retained in the skin after topical administration of several formulations was determined. It was found that OA content markedly increased TEN absorption when compared to the control gel; the highest drug flux was obtained by 15% of OA. The absorption rate of TEN increased in parallel with increasing OA concentration, due to the alteration of the stratum corneum caused by this enhancer. Moreover, the action of OA is likely to be strongly dependent on the vehicle used since drug penetration tended to increase with increasing PG content in the vehicle, especially at the high OA concentrations. Contrary to our expectations, addition of CD complexes did not produce a significant further enhancement. Skin pretreatment with OA, independently of the vehicle used to dissolve the fatty acid, dramatically improved TEN percutaneous penetration. The amount of TEN retained in the skin was related to the flux values obtained with each formulation.

Administration, Cutaneous↗

PubMed2001

Interaction of tenoxicam with cyclodextrins and its influence on the in vitro percutaneous penetration of the drug.

Solid complexes of tenoxicam (TEN) with cyclodextrins (CDs), in a 1:1 molar ratio, were obtained by the coprecipitation method and characterized by x-ray diffractometry, infrared spectroscopy, and differential scanning calorimetry. The binding capacity of the CDs with TEN was also demonstrated in aqueous solution and in water-propylene glycol mixtures. The purpose of this study was to determine the effect of CDs on the in vitro percutaneous penetration of TEN from carbopol gels, taking into account the role of the CD cavity size and the nature of the substituents. The effect of pretreatment was studied too. In vitro permeation experiments were carried out on Franz diffusion cells using cellulose nitrate membranes and abdominal rat skin. In these results, the release rates of the drug scarcely decreased when the CDs were added, probably because of a lower concentration of the free drug and an increased gel viscosity. However, it was also found that CDs, particularly gamma-CD and M-beta-CD, can improve slightly TEN absorption through the skin. Pretreatment studies with CDs, however, provided no effects on TEN permeation, but lag time was markedly reduced, suggesting a faster partitioning of TEN into the skin. Therefore, the use of pretreatment with CDs would be interesting when a quick action of the drug is desired.

Acrylic Resins↗

PubMed2001

Surgical correction of hyperopia: clear lens extraction and laser correction.

Modern ophthalmology offers a series of surgical procedures to correct a wide range of hyperopia and hyperopic astigmatism. Varies excimer lasers and thermal lasers have been proven safe and effective. Phakic implants and clear lens extraction offers alternatives for moderate to high hyperopic patients. Indications, techniques, and clinical study results were reviewed and summarized.

Cornea↗

PubMed1999

Influence of propylene glycol and isopropyl myristate on the in vitro percutaneous penetration of diclofenac sodium from carbopol gels.

The influence of propylene glycol (PG) on the in vitro penetration of diclofenac sodium (DFS) through a synthetic membrane and abdominal rat skin from carbopol gels was investigated using Franz-type diffusion cells. The combined effect of isopropyl myristate (IPM) and PG was also evaluated. It was found that the penetration through the synthetic membrane was well described by the Higuchi model. The gel containing 40% PG showed the highest release rate, indicating that a releasing maximum exists for PG content which provides the fully solubilized drug in the vehicle. When using rat skin as the barrier, the penetration rate was controlled by the membrane. DFS flux decreased with increasing PG content of the gels due to an increase of the drug affinity to the vehicle. A cosolvent action of PG was evident. However, the combination of PG and IPM resulted in a synergistic enhancement of DFS flux. Maximum enhancing activity was obtained from gels containing 40% PG, which yielded an enhancement ratio of about 8. Increasing IPM content from 3 to 5% increased the flux and decreased the lag time taken to reach a steady-state level.

Acrylic Resins↗

PubMed1997

[Spinal cord compression in non-Hodgkin's lymphoma. A study of 10 patients].

Spinal cord compression is an infrequent event in patients with non-Hodgkin's lymphomas (NHL) and early diagnosis and therapy are required. The main clinical and histologic characteristics as well as the response to therapy in 10 NHL patients with spinal cord compression diagnosed at a single center in a 7-year period are referred. The main initial clinical manifestations were pain in dorsal or lumbar regions (5 cases) and paraparesia or paraplegia (5 patients). Infection by human immunodeficiency virus (HIV) was present in four cases. In 8 patients spinal cord compression was the initial manifestation of NHL. Pathologic diagnosis showed intermediate or high-grade lymphoma in 8 out of 10 cases and immunologic phenotype was B-cell in all cases. Laminectomy followed by radiation therapy and chemotherapy was performed in 4 cases, radiotherapy and chemotherapy in two, isolated chemotherapy in 3 and radiation therapy was administered to the remaining case. Complete response was observed in 4 cases and 6 cases were resistant to treatment. No patient with HIV infection responded to treatment. Six patients had died, median survival time for the whole series being 4 months, and the actuarial probability of survival was 40% at the first year.

Adult↗

PubMed1996

Factor H co-purifies with thrombospondin isolated from platelet secretate.

Thrombospondin is a trimeric glycoprotein that has several known functions, including roles in platelet aggregation, phagocytosis and an inhibitor of angiogenesis. Typically the molecule is isolated from platelet secretate by heparin affinity followed by sizing chromatography. In this study, purity is analysed by 7.5% SDS-PAGE under reducing conditions when thrombospondin monomers run as a band at around 180 kDa. Under nonreducing conditions of 7.5% SDS-PAGE, thrombospondin does not penetrate beyond the stacking gel; however, under these conditions a major contaminating band can be seen which, upon reduction, merges into the thrombospondin band. Further purification of this contaminating protein was achieved by DEAE chromatography and it was identified as Factor H by peptide sequencing and immunoblotting. Factor H function was demonstrated by the ability of the protein to function as a cofactor in the Factor-I-mediated cleavage of C3b. Since Factor H has several known functions, such contamination could confound functional studies of thrombospondin thus purified and a pre-elution step of the heparin affinity column is recommended.

Amino Acid Sequence↗

PubMed1996

In vitro percutaneous absorption of piroxicam through synthetic membranes and abdominal rat skin.

The in vitro release of piroxicam from carbomer gels and its penetration through isopropyl myristate impregnated membranes and abdominal rat skin were investigated. Attempts were made to relate the differences in the release rate with physicochemical properties of the drug and the vehicle. The results showed that piroxicam is released from the topical gel formulations and diffuses through skin. It is suggested that although piroxicam flux across abdominal rat skin was lower than through isopropyl myristate membranes, this kind of membranes can be used in preliminary screening among the different piroxicam formulations.

Animals↗

PubMed1996

The role of induction (neoadjuvant) chemotherapy in stage IIIA NSCLC.

Induction (neoadjuvant) chemotherapy has become an accepted treatment for stage IIIA (T1-3N2M0) non-small cell lung cancer. In two recent randomized trials, neoadjuvant chemotherapy plus surgery gave an increase in median survival at least fivefold greater than surgery alone. The Spanish Lung Cancer Group trial of preoperative chemotherapy, in which the cisplatin dose was randomized to either 50 mg/m2 or 100 mg/m2 plus 3 g/m2 ifosfamide and 6 mg/m2 mitomycin, examines the effect of K-ras gene mutations on tumor response and survival. Patients whose tumors contain K-ras gene mutations are more likely to develop distant metastases and have lower median survival than patients without such mutations. Microsatellite instability seems to be a frequent mechanism of genetic aberrations. Knowledge about these genetic alterations could have prognostic importance and may identify the patients who should receive the most aggressive additional treatment.

Carcinoma, Non-Small-Cell Lung↗

PubMed1994

Upregulation of human neutrophil CD59, a regulator of the membrane attack complex of complement, following cell activation.

CD59 is a membrane glycoprotein that regulates the membrane attack complex of complement and protects cells from autologous complement damage. Human polymorphonuclear leucocyte (PMN) expression of CD59 was confirmed by flow cytometry following staining with mAb 1F5, and western blotting revealed staining of a 19-23 kDa band. Warming of PMN from 4 to 37 degrees C resulted in spontaneous CD59 upregulation. A dose-dependent increase in expression following PMN stimulation with FMLP was observed and occurred within minutes, indicating that new protein synthesis was not required. Treatment of PMN with calcium ionophore A23187 resulted in similar increases in CD59 expression. This occurred in the presence or absence of extracellular calcium, indicating that upregulation was dependent on release of calcium from intracellular stores. Evidence for a mobilizable intracellular pool of CD59 was obtained by detection of increased binding of 1F5 following PMN permeabilization; CD59 could also be re-expressed after stripping by phosphatidylinositol specific phospholipase C (PI-PLC) by treatment with FMLP or A23187. There was a correlation between CD59 upregulation and lactoferrin release, suggesting that stores of CD59 may be associated with secondary granules. These studies indicate that PMN expression of CD59 is enhanced by cell activation and suggest the presence of an intracellular pool of CD59 which can be translocated to the cell membrane upon PMN stimulation.

Antibodies, Monoclonal↗

PubMed1991

A new scalp flap for baldness.

The technique and results of a new scalp flap that solves frontal baldness are described. As a bipediculate flap it offers a great amount of hair when advanced and has a low rate of complications. This kind of flap has been used by us for four years in 36 patients in the age group between 20 and 60 years. The results obtained with the flap have been very satisfactory.

Adult↗

PubMed1991

Sagaxine, the protamine from Sardinops sagax. Characterization, sequence and secondary structure prediction.

This paper describes the isolation, purification and full characterization of the protamine from Sardinops sagax. The protein was purified by both gel filtration and ion exchange chromatography and its amino acid composition, electrophoretic behaviour and sequence were determined. We postulate that the protamine exhibits microheterogeneity with a major and a minor component. The molecular weight for the major component is 4377, as calculated from the sequence. The N-terminal amino acid is proline and the C-terminal is arginine. The amino acid composition is: Thr-Ser-Glx-(Pro)2-Gly-(Ala)3-(Val)2-(Lys)2-(Arg)20 The secondary structure for the protamines was also predicted and a revision of our previously published results in this area is discussed. We have called this protamine Sagaxine and an overall comparison with the hitherto described fish protamines is also made.

Amino Acid Sequence↗

PubMed1990

Fat injection.

The results of grafts of fat obtained through liposuction are presented. They are the outcome of the current revitalization of the old technique of fat extraction and transplant. Both doctor and patient should be aware that a successful treatment is achieved through continuity. Fat grafts evolve with respect to time and permanence with reabsorption a part of the normal evolutionary process. Fat reinjection is a consequence of tissue reabsorption or a complement of the preceding injection. There is no complication associated with repeated reinjection. All cases reported here include patients with two or more reinjections, depending on their pathology and evolution.

Adipose Tissue↗

PubMed1988

Fluorescence studies on clupein protamines: evidence for globular conformation.

Conjugates of fluorescein isothiocyanate with clupein YI, YII and Z, the protamines from Clupea palasii, were prepared and their fluorescence utilized to determine the rotational relaxation times of the proteins. All conjugates exhibited single component lifetimes near 4.05 ns. Linear isothermal Perrin plots were obtained for all conjugates; these data indicated rotational relaxation times of 3.33 ns for clupein YI and YII and 3.19 ns for clupein Z. These results and the results from our previous studies lead us to postulate globular conformations for the three proteins with hydrated molecular diameters of 22 A. Based on these findings a three dimensional model for Clupein YII is proposed.

Clupeine↗

PubMed1988

[Comparative study on lipoinjection and other methods].

This paper present the method and technical description of the fat graft injection with the material obtained from the same patient (donor area) to correct the affected area (receptor), and also have the finality to remark the good aesthetic results and the patient acceptance. A comparative of the procedure advantage with other filling materials is effected, providing the highly permanence and minimal complications. An evaluation since 1984 is made, referring the innocuousness and facility of the method. We employ the autogenous tissue to make the aesthetic correction of the face wrinkles, nasolabial folds, and depression. With this technique we improve defects like facial atrophy, radiodystrophies, acne, scars, etc. In the same way we use the fat injection in combined procedures with lipoplasty, blepharoplasty, rhinoplasty and facelift. We made this histological study taking postoperative biopsies in some patients.

Adipose Tissue↗

PubMed1987

Induction chemotherapy with cisplatin, bleomycin and methotrexate in advanced head and neck cancer--lack of therapeutic gain.

Seventy patients with stage IV head and neck cancer were treated by two courses of induction chemotherapy followed by surgery plus postoperative irradiation (7) or radical radiotherapy (62). One patient renounced to further treatment after chemotherapy. Each chemotherapy course consisted of methotrexate (40 mg/m2 days 1 and 14), bleomycin (10 mg/m2 days 1, 7 and 14), and cisplatin (50 mg/m2 day 4). Three patients did not complete the two courses of chemotherapy planned due to bad tolerance whereas the rest of the patients tolerated chemotherapy well. 2 CR (3%) and 35 PR (50%) were achieved for an overall response rate to chemotherapy of 53%. 35 (50%) CR were achieved with the whole treatment schedule. The 5-year disease-free survival is 26% for the whole group of patients. The prior response to chemotherapy neither influenced the complete responses to treatment nor the relapse-free survival. The addition of this chemotherapy to conventional treatment was of no value.

Adolescent↗

PubMed1987

External beam irradiation for T1, T2-3 and T4 transitional cell carcinoma of the urinary bladder.

Fifty-seven patients with T1 transitional cell carcinoma of the bladder, 57 patients with T2-3 and 10 patients with T4 were treated by radical irradiation +/- salvage cystectomy. Thirty-five patients with T1 were treated by transurethral resection (TUR) plus local chemotherapy +/- salvage cystectomy. Eleven patients with T2-3 were treated with 5 X 4 Gy in one week followed by cystectomy while four patients with T2-3 were treated with 40 Gy in 4 weeks also followed by cystectomy. Five patients with T4 were treated with 40 Gy in 4 weeks plus cystectomy. Seven year survival rates are: 69% for T1 treated by radical irradiation, 43% for T1 treated by TUR (p less than 0.02), 36% for T2-3 treated either by radical irradiation or 5 X 4 Gy plus cystectomy, and 18% for T4 treated by radical irradiation. All the survival rates indicated are free of disease and include the cases in which salvage cystectomy was successfully performed. Sixty per cent of the cured patients conserved very good functional bladders. We believe that external beam irradiation plus salvage cystectomy is indicated in the treatment of T1 and T2-3 tumours of the bladder.

Adult↗

PubMed1986

[Surgical treatment of baldness. 20 years' experience].

After giving an introduction on the surgical treatment of alopecia in the last years, we talk about our experience with more than 2,500 patients. We discussed in individual chapters each one of the four major methods for the surgical management of male pattern alopecia: punch grafts, strip grafts, scalp reduction, flaps and combined techniques. In general more than the half of those patients have been seen and controlled for long time, because the most of them have continued with the clinic treatment in correspondence with the skin-hair pathology.

Alopecia↗