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Biomedical subjects

M Millán

Publications and source records attributed to M Millán.

At least 19 recordsLinked to original sources
PubMed2001

Multiple idiopathic small bowel strictures: report of three cases.

Multiple strictures of the small bowel are relatively rare. In many cases, a distinct cause can be defined, but some strictures are unexplainable by any specific mechanism and have been termed 'idiopathic' small bowel strictures. We present 3 cases of multiple small bowel strictures in which the affected segments were studied with perioperative photoplethysmography, in vivo specimen angiography and pathology. Neither photoplethysmographic alterations nor structural vascular lesions were found.

Adult↗
PubMed2000

Percolation thresholds in ultrasound compacted tablets.

Twenty matrix systems with different KCl content (as drug model, from 10 to 90% w/w) and Eudragit RS-PM (as inert excipient) were prepared using an ultrasound-assisted press and a traditional eccentric machine. The release behavior from both types of matrices was examined; the kinetic parameters for the release (intrinsic dissolution) and the technological properties of the final tablets (total porosity) were used to estimate the percolation threshold for the drug model and the excipient in both systems. For the systems compacted by ultrasound (US) the estimated value for the excipient percolation threshold ranges from 13.4 to 20.2% v/v (lower than that found for traditional tablets), that agrees with a continuum percolation model suggesting the presence of a continuum phase inside the tablet. This depends on a thermoplastic deformation of Eudragit RS-PM under ultrasound, that destroyed the particulate system of the excipient and transform it into a continuum medium. The percolation threshold for KCl ranged from 58.6 to 61.0% v/v for US and from 26.7 to 42.2% v/v for the traditional tablets. The higher value for ultrasound compacted tablets can be explained by the difficulty of KCl to outcome from a matrix containing insoluble phase that surrounds KCl crystals.

Excipients↗
PubMed1998

The role of the drug/excipient particle size ratio in the percolation model for tablets.

PURPOSE: In previous papers, a linear relationship between drug particle size and drug percolation threshold was found in inert matrix tablets. The main objectives of the present work are: to study the influence of the excipient particle size on the drug percolation threshold and to investigate if the change in the drug percolation threshold is due either to the absolute or to the relative drug particle size. METHODS: Matrix tablets have been prepared using KCl (7 different particle size fractions) as a drug model and Eudragit RS-PM (4 granulommetric fractions) as matrix forming material. In vitro release assays were carried out on the 66 lots of tablets. The drug percolation thresholds were estimated following the method of Bonny and Leuenberger. RESULTS: The particle size of the excipient has shown an opposite effect to the drug size on the drug percolation threshold. Nevertheless, the influence of drug and excipient sizes on the drug percolation threshold are of the same magnitude. CONCLUSIONS: The drug percolation threshold depends linearly on the relative drug particle size. This finding is in agreement with percolation theory and can facilitate the use of the percolation threshold as a preformulation parameter to improve the pharmaceutical dosage forms design.

Chemistry, Pharmaceutical↗
PubMed1997

Prevalence of osteomyelitis in non-healing diabetic foot ulcers: usefulness of radiologic and scintigraphic findings.

The study was conducted in order to assess the prevalence of osteomyelitis and the predictive value of radiographic (xR) and combined Tc 99-bone and leukocyte scanning (CS) findings in diabetic foot ulcers that met criteria for hospital admission (FUH). Out of 150 episodes of ulceration managed in an outpatient basis, 33 (in 28 NIDDM patients) requiring admission were evaluated. In all cases plain xR and CS were carried out. Seventeen episodes (51.5%) had a good outcome (healed or improving, at the time of the last follow up). Osteomyelitis was found in 21 episodes and 14 (66.6%) of them required an amputation. In 13 cases where xR showed characteristic radiologic changes of osteomyelitis (11 of them had a positive CS) 11 (84.6%) underwent an amputation. However, when osteomyelitis was diagnosed only by a positive CS, only 3/8 (37.5%) required a toe amputation. Severe peripheral vasculopathy was present in 44% of cases who required amputation and only in 17.6% of those who did not. We conclude that in FU underlying osteomyelitis is frequent and associated to a higher amputation rate than when no bone infection is identified (66.6 vs 17%), even when corrected for vascular status (OR 11, CI 95% 1.65-74.2), with a worse outcome when xR changes are already present.

Aged↗
PubMed1996

[Presence of markers predictive of type I pre-diabetes mellitus status in relatives of patients with type I diabetes mellitus].

BACKGROUND: The aim of this study was to analyze the predictive factors of IDDM in first degree relatives of IDDM patients. SUBJECTS AND METHODS: From 1992 to 1994, 1,053 first degree relatives were screened for measuring islet cell antibodies (ICA) by indirect immunofluorescence (iFl). In all ICA positive subjects, beta cell function was analyzed by intravenous glucose tolerance test (IVGTT) and other immunologic parameters were also studied: anti-insulin antibodies (IAA) by radiobinding and antibodies to glutamic acid decarboxylase (GADAb) by ELISA methods. RESULTS: ICA were found in 3.1% of the first degree relatives. IVGTT showed a significant decrease in acute first phase of insulin response to glucose (IRI 1 minute + 3 minute) in those with ICA > or = 20 JDF units. In patients with ICA > or = 20 JDF units, 20% were found to be positive for IAA and 40% were positive for GAdAb. Thirty-one percent (10/32) of ICA positive first degree relatives fulfilled prediabetes criteria. During follow-up, 40% (4/10) of these prediabetic patients developed IDDM. CONCLUSION: This study confirms the possibility of identifying among first degree relatives of IDDM patients the subgroup with high risk of developing IDDM thus allowing the initiation of therapy for preventing or delaying IDDM onset.

Adolescent↗
PubMed1993

Tamoxifen failure in medullary thyroid carcinoma.

We report the results of short-term tamoxifen treatment (20 mg two times a day orally) in 2 patients with metastatic medullary thyroid carcinoma. Patient A had a rapid tumor progression with development of Cushing's syndrome before initiation of tamoxifen treatment. Patient B had a slowly progressive course. In both cases, neither clinical nor biochemical improvement were observed, after 1 and 3 months of tamoxifen therapy, respectively.

Adult↗
PubMed1983

17-ketosteroid reductase deficiency in an adult patient without gynaecomastia but with female psychosexual orientation.

A 24 years old male with pseudohermaphroditism due to a deficiency in 17-ketosteroid reductase activity is described. Plasma delta 4 is 21 times higher than normal for an adult male, delta 4/T is greater than 6, both E1 and F2 are elevated and E1/E2 = 3. There is very slight modification of delta 4 on administration of ACTH, dexamethasone, hCG and fluoxymesterone. Steroid concentrations in the spermatic veins and arteries confirm the testicular origin of the increased secretion of delta 4 and E1 and show a lower secretion by the cryptorchidic testis. In vitro testicular tissue incubation and fibroblast studies confirm the 17-ketosteroid reductase deficiency and rule out any other anomaly as the cause of the ambiguous genitalia. Psychologically the patient seemed to be identified with a female social and sexual role in spite of her advanced degree of virilization.

17-Hydroxysteroid Dehydrogenases↗
PubMed1983

[Sacrococcygeal tumors. Experience of 42 cases].

From 1966 to 1981, at "La Paz" Children's Hospital, Madrid, 42 patients with ST were studied. We exclude 4 stillborn, the remaining 38 underwent 40 surgical operations, 69% in the first week of life. The aim of the study is to classify and organize from the clinical and pathological points of view the usual equivocal terminology. From a clinical point of view, sex, localization and age at diagnosis were the usually described for these tumors. The relationship of age with malignancy is pointed out. Special emphasis is made on the pathological information about undifferentiated blastodermic tissues, like neuroblasts pointing out their low influence in prognosis. 79% were mature teratomas and 21% malignant tumors (Yolk sac and embrional carcinoma).

Bone Neoplasms↗
PubMed1981

[Glycosylated hemoglobin as an index of diabetes mellitus control (author's transl)].

Glycosylated hemoglobin ((HbA1c) is formed by structural modification of HbA in a slow and irreversible non-enzymatic reaction. Its concentration is proportional to mean blood glucose levels during approximately four weeks, being therefore a useful index of diabetes mellitus control. The introduction of a microcolumn chromatographic method that measures together the subfractions HbA1a + b + c (fast Hb) and is well correlated to HbA1c has permitted the routine clinical measurement of this parameter. The authors used this method to study the levels of glycosylated hemoglobin in normal subjects, acutely decompensated diabetics, and diabetic outpatients classified according to their degree of control. The highest levels were detected in acutely decompensated patients and in those with chronic poor compensation. It is concluded that HbA1 constitutes a good index of compensation in diabetes, and that it may in the future unify existing criteria on the disease, contributing to clarify the problems about the correlation between the degree of compensation of diabetes and the incidence and evolution of its specific complications.

Blood Glucose↗