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Biomedical subjects

M Alecu

Publications and source records attributed to M Alecu.

18 recordsLinked to original sources
PubMed1999

Traditional and MLC based dose compensator design for patients with hip prostheses undergoing pelvic radiation therapy.

Perturbations in the dose distribution caused by a hip prosthesis when treating pelvic malignancies can result in unacceptable dose inhomogeneities within the target volume. Our results, obtained by in vivo exit dose measurements with diodes, showed a 55% reduction in the dose at the exit dmax of a lateral 15 MV photon beam after passing through a bilateral cobalt-chrome alloy hip prosthesis. Such an inhomogeneous dose distribution may decrease the curability. Solutions such as treatment techniques to avoid the prosthesis are often not the best choice as the dose to the rectum may be unacceptably high. In this work an alternative method of dose compensator is presented. Two types of dose compensators were designed based on a 3-D treatment planning system and CT images of a pelvic phantom containing a hip prosthesis: one was fabricated from a polyethylene-lead slab in the representation of step fringes and placed on a tray in the path of the beam while the other was produced by the use of several fields shaped with a multileaf collimator. The calculation procedures developed by the authors for generating the compensators are described. Results of film measurements performed in a phantom with and without the compensators in place are discussed.

Alloys↗
PubMed1999

In-vivo rectal dose measurements with diodes to avoid misadministrations during intracavitary high dose rate brachytherapy for carcinoma of the cervix.

Our purpose in this paper is to present an in vivo dosimetry program designed both for measuring the rectal dose and for avoiding misadministrations in gynecological intracavitary implants. A device containing an energy compensated diode was specially designed for these measurements. Our calibration procedure as well as the clinical protocol is described. Measurements have been performed for 50 treatments delivered with a Fletcher Suit Delclos applicator. The calculated and in vivo measured values for the "20% reading," i.e., the dose delivered to the diode by the initial 20% of the total dwell time, agreed to within 15%.

Brachytherapy↗
PubMed1998

A method to improve the effectiveness of diode in vivo dosimetry.

A routine diode in vivo dosimetry program based on a combination of entrance and exit dose measurements was clinically implemented in the radiation oncology department of Grace Hospital, Detroit, in January 1995. The delivered dose has been monitored by taking weekly measurements. The calibration of the diodes and the in vivo dosimetry protocol for this new, more effective type of dose verification is presented. The problems encountered within the program are discussed along with our solutions.

Calibration↗
PubMed1997

Dose perturbations due to in vivo dosimetry with diodes.

In vivo dosimetry performed with semiconductor detectors is a reliable method for patient dose control. The purpose of this study is to evaluate the perturbations introduced in the patient's absorbed dose distribution by three types of commercially available diodes (Isorad, Sun Nuclear Corp.; model 114200, 114300 and 114400) from the same company and to present possible solutions for minimizing this side-effect.

Humans↗
PubMed1992

Intralesional human leukocyte interferon treatment alone or associated with IL-2 in non-AIDS related Kaposi's sarcoma.

Patients with classical European Kaposi's sarcoma were treated by intra- and peritumoral injections of human alpha leukocyte interferon (IFN) (12 cases) or, alternatively, with IFN and naturally synthesized IL-2 (8 cases). All the patients were HIV negative with tumors which had been present for at least six months. In each patient, one tumor received 1 ml (50,000 IU) IFN alone or alternatively associated with 1 ml IL-2 twice a week for 4-6 weeks; another nodule situated 10-12 cm away was considered as a control and remained uninjected. The clinical follow-up revealed that, in the same patient in the same anatomical area, the treated nodule was cured in all the investigated cases; the untreated one was not. These data strongly suggest that IFN is the factor responsible for the involution and final cure of these Kaposi tumors treated by perilesional inoculations. Association with IL-2 (and certainly also other interleukins) increases the beneficial clinical activation of the tumor involution. Histological examination showed that important histopathological changes occur in the treated nodules: complete disappearance of the Kaposi's aspect, fibrosclerous modifications progressively replacing the fibroblasts characteristic of Kaposi's sarcoma, abundant infiltrations of leukocytes, especially lymphocytes and necrotic patches, often with hemorrhagic centers. IL-2 association seems to especially induce this last type of histological phenomenon.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

The interleukin-1, interleukin-2, interleukin-6 and tumour necrosis factor alpha serological levels in localised and systemic sclerosis.

Serological level of interleukin-1 (IL-1), Interleukin-2 (IL-2), Interleukin-6 (IL-6) and tumour necrosis factor (TNF) alpha was investigated in 26 patients with scleroderma, divided into three lots, by the extension and the progress of the disease. Determinations were performed by ELISA in attack and in remission (after treatment with prednison). Normal values: IL-1 (0-5 pg/ml), IL-2 (0-5 pg/ml), IL-6 (5-15 pg/ml), TNF (0-16 pg/ml). Lot A. Results obtained at the first determination showed that IL-1 is elevated in 4 cases (10-15 pg/ml), IL-2 in 5 cases (10-32 pg/ml), IL-6 in 5 cases (15-42 pg/ml) and TNF in 4 cases (18-34 pg/ml). In the second determination IL-1 was increased in 1 case (8 pg/ml), IL-2 in 1 case (9 pg/ml), IL-6 in 2 cases (12 pg/ml) and TNF was normal. Lot B. In the first determination IL-1 was elevated in 5 cases (8-12 pg/ml), IL-2 in 5 cases (10-15 pg/ml), IL-6 in 7 cases (16-20 pg/ml) and TNF was raised in 3 cases (18-25 pg/ml). At the second determination IL-1 showed normal values in all the cases, IL-2 was raised in 2 cases (10 pg/ml), IL-6 in 2 cases (12.15 pg/ml), TNF in 1 case (20 pg/ml). Lot C. In the first determination there were raised values in 4 cases for IL-1 (6-8 pg/ml), 3 cases for IL-2 (10-18 pg/ml), 5 cases for IL-6 (18-20 pg/ml), 2 cases for TNF (20 pg/ml). At the second determination IL-2 was elevated in 1 case (10 pg/ml), IL-6 in 1 case (15 pg/ml). We consider that in scleroderma there is a disturbance of the investigated cytokines due to the activation and involvement of the secretory cells into the pathogenesis of the disease. The increase of the serological levels of IL-1, IL-2, IL-6 and TNF depends on the extension of the lesions and the clinical and biological activity periods of the disease. The absence of the increase of the serological levels does not exclude their activity at the lesional site.

Adolescent↗
PubMedDate not supplied

ICAM-1, ELAM-1, TNF-alpha and IL-6 in serum and blister liquid of pemphigus vulgaris patients.

The levels of ICAM-1, ELAM-1, TNF-alpha and IL-6 were determined in 12 patients with pemphigus vulgaris (PV) both in serum and the blister liquid. As a control, the same parameters were determined in 7 patients with herpes zoster (HZ). The patients with PV presented significantly higher values of ICAM-1 in the blister liquid, as compared to the serum values. The values of TNF-alpha and IL-6 were increased both in serum and the blister liquid. The ELAM-1 values did not show significant differences between serum and the blister liquid. In HZ patients, the blister liquid values did not significantly exceed the serum values both for ICAM-1 and ELAM-1. TNF-alpha and IL-6 presented high values both in serum and the blister liquid. We consider that the high values of ICAM-1 in the blister liquid from PV patients suggest the involvement of this adhesion molecule in the PV pathogenic features. The implication of ICAM-1 could be nonspecific and limited, and could possibly represent a reaction to the destruction of the desmosomal bonds within keratinocytes.

Adult↗
PubMedDate not supplied

Highly active effect of alpha interferon in blocking the cutaneous delayed hypersensitivity.

A group of 13 patients with contact dermatitis to various chemical compounds such as potassium dichromate, nickel sulphate, formaldehyde and balsam of Peru, was investigated by patch test and by the agreement between the history of disease and the patch test, the specific allergen involved in each special case could be demonstrated. Two-three days after the first patch test three normal skin areas were chosen. The first area was intradermally infiltrated with alpha-2a Interferon (IFN) (100,000 I.U. in 1 ml), the second area was infiltrated with saline and the third area, considered as control, did not receive any treatment. Once more the corresponding allergen was applied into the skin in a second patch-test. After 48 hours in the IFN infiltrated area, only the delayed contact hypersensitivity become negative thus proving that alpha-2a IFN behaves as an efficient inhibitor of these immune effector reactions. Since the lymphocytes involved in the delayed type hypersensitivity reactions (in our case contact dermatitis) belong to the T helper line, i.e., are CD-4 positive cells we conclude that alpha-2a IFN in vivo is an efficient inhibitor of the activation of these cells. This effect achieved by any CD-4(+) DTH clones does not depend on their antigenic specificity. Some clinical trials are now in progress in our laboratory to turn to account this important biological effect in the clinical practice as an efficient inhibitor in skin contact dermatitis.

Adolescent↗
PubMedDate not supplied

Therapeutic effect of intralesional interferon (Roferon) in squamous cell carcinoma.

Recombinant alpha-2 interferon (IFN)--Roferon--100,000 IU/ml was intralesionally administered in 8 cases of squamous cell carcinoma (SCC) three times a week during 4-6 weeks in inoculations of 1 ml each. The therapeutic effect was scored as major--more than 60% reduction of the tumor size, moderate--30-60% reduction of the tumor mass and, nonreactive--less than 30% reduction of the tumor size. Three cases showed a major reduction, three showed a moderate reduction and two patients showed no reduction of the tumor volume. Histopathological examination of the surgically removed tumors after completion of the Roferon administration confirmed the clinical diagnosis of squamous cell carcinoma and revealed that an intense leukocyte, mainly lymphocytes, infiltration can be observed along with necrotic centers, progressively surrounding and reducing in size the tumor islets, thus proving an intense activation of the immune effector reactions against tumor cells.

Carcinoma, Squamous Cell↗
PubMedDate not supplied

Human leukocyte interferon treatment associated with IL-2 in the non-AIDS related Kaposi's sarcoma.

Patients with classical European Kaposi's sarcoma have been treated by intra- and peritumoral injections of human alpha-leukocyte interferon (IFN) (12 cases) or alternatively with IFN and naturally synthetized IL-2 (8 cases). All the patients were HIV negative their tumour appearing at least six months before. In each patient one tumour received 1 ml (50,000 IU) IFM alone or associated, alternatively with 1 ml IL-2, twice a week during 4-6 weeks, whereas another nodule situated 8-10 cm apart was considered as control and remained uninjected. The clinical follow-up revealed that in the same patient in the same anatomical area the treated nodule was cured in all the investigated cases while the untreated nodule was not. These data undoubtedly prove that IFN is the responsible factor for the involution and final cure of the Kaposi tumours treated by perilesional inoculations. Association with IL-2 (and certainly also other interleukins) increases the beneficial clinical effect activating the tumour involution. The histological examination showed that important histopathological changes occur in the treated nodules, i.e., complete disappearance of the Kaposi's aspect; fibrosclerous modifications progressively replacing the abundant fibroblastic cells characteristic of Kaposi's tumour; abundant infiltrations of leukocytes especially lymphocytes; necrotic patches often appearing along with hemorrhagic centers. IL-2 association seems to frequently induce especially this last type of histological phenomena.

Adult↗
PubMedDate not supplied

Investigations of magnesium, histamine and immunoglobulins dynamics in acute urticaria.

In 42 urticaria patients, magnesium, histamine and IgE were dosed. Magnesium, IgE and histamine variations were followed in urticaria evolution, during acute phase and clinical remission. We noticed magnesium, histamine, IgE values variations depending on disease evolution and applied therapeutic scheme. Therefore: At disease starting point, histamine presented 3.5 times higher values than the normal ones. The value decreases following a curve which tends to reach normal values during clinical remission. At disease starting point, magnesium presented values under the inferior limit of the normal, 0.5 m mol/L respectively, as a mean. The value increases towards the normal limit during clinical remission. Immunoglobulins E follow a similar curve to histamine one, presenting 1,250 U/L values at the starting point, that, under medication, influence decrease between normal limits (800 U/L), during clinical remission. Analyzing the variations of biochemical parameters, the authors emphasize magnesium substitution treatment in urticaria.

Acute Disease↗
PubMedDate not supplied

Intralesional human leukocyte interferon treatment in the non-AIDS related Kaposi's sarcoma.

Twelve patients with classical European Kaposi's sarcoma have been treated by intra- and peritumoral injections of human alpha leukocyte interferon (IFN)--Ginterferon ("V. Babeş Institute", Bucharest). All the patients were HIV negative their tumour appearing at least six months before. In each patient one tumour received 1 ml (50,000 IU) IFN twice a week during 6-7 weeks whereas another nodule considered as control remained uninjected. After treatment biopsies of both the IFN-treated and the untreated nodules were performed in 8 patients and histological examinations were carried out. The clinical follow-up revealed: The skin colour progressively changed from purple red to dark reddish or even brown in all the IFN-treated tumours and only in 3 of the untreated ones (p less than 0.001). The consistency of the nodules decreased in all the treated tumours and only in 2 of the untreated ones (p less than 0.001). The tumour thickness decreased in 9 of the treated tumours and in none of the untreated ones (p less than 0.001). The surface of the lesions decreased in 4 of the treated nodules but not in the untreated ones (p less than 0.05). The IFN-inoculated tumours were gradually cured even in the four cases in which during the treatment some other tumour progressed or even new lesions appeared. The histological examination showed that: all the IFN-treated tumours were either predominantly sarcomatous or predominantly angiomatous. The typical Kaposi aspect disappeared totally in 2 of the cases examined, and in 3 a fibrosclerotic massive change was obvious.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Interferon efficiency in the treatment of herpetic dermatites. II. Comparison between human leukocyte interferon (Ginterferon) and a recombinant interferon (Roferon).

The comparative efficiency of a recombinant interferon-Roferon (R-IFN) and a human, naturally synthetized interferon-Ginterferon (G-IFN), applied as ointments in the treatment of herpetic dermatites, was studied in a blind trial. It was found that R-IFN in doses of 20,000 IU/g has practically similar results as G-IFN in doses of 10,000 IU/g therefore half the dose of the former product. Thus both preparations reduced significantly the mean duration of a herpetic dermatitis attack and both proved more efficient on smaller lesions (less than 2 sq.cm) than on larger ones (over 2 sq.cm). Likewise with both preparations the reduction of the healing period was more marked when administered in the first 2-3 days after onset. It was also found that the arrest of new vesicle appearance after two days of treatment is a reliable clinical criterion for the estimation of IFN capacity to block effectively viral multiplication in the host's epithelial cells. Finally the efficacy of both R-IFN and G-IFN proved similar whatever the localization of disease (oral or genital) or in their capacity to prevent relapses or the appearance of bacterial complications.

Clinical Trials as Topic↗
PubMedDate not supplied

Interferon efficiency in the treatment of herpetic dermatites. I. A double-blind placebo controlled study.

The effect of an alpha human leukocyte interferon (IFN) locally applied as an ointment in herpetic dermatitis was investigated in a double blind trial. It was observed that IFN reduced significantly by 25-42% the mean healing period of attacks. This reduction was more important if the period till disappearance of vesicles was considered than if the period till complete epithelialization was taken into consideration. Likewise IFN was proved more effective if administered within the first 2-3 days after onset of attacks than 5 days after. As compared with the group which received placebo the effect of IFN was more marked when the size of the lesions was smaller than 2 sq. cm. IFN did not reduce significantly the number of cases with bacterial superinfections nor the rate of relapses in the first three months after treatment. These results suggest that alpha IFN administered as an ointment is an efficient agent in blocking viral multiplication and therefore useful in the treatment of herpetic dermatitides whatever their localization.

Clinical Trials as Topic↗
PubMedDate not supplied

Tumoral infiltrate after local treatment with interferon in squamous cell carcinoma.

Using monoclonal antibodies UCHL-1 (T lymphocytes), MT-1 (pan T) and L-26 (B lymphocytes) in the study of the tumoral infiltrate after local treatment with alpha interferon (Roferon) in patients with squamous cell carcinoma of the lower lip, it was observed that: the proportion of UCHL-1 positive cells was between 30% and 80%, the proportion of MT-1 positive cells was of 85% and that of the L-26 positive cells was of 30% of all the cells in the infiltrate. In the area in which after treatment with interferon the tumoral structures had disappeared, the proportion of T lymphocytes was smaller than in the areas in which the tumoral structures were still present. The therapeutic effect of interferon is due both to the direct effects on the tumoral cell and also to the indirect effects, namely the activation of the cytotoxic T lymphocytes and of other cells in the tumoral infiltrate.

Adult↗
PubMedDate not supplied

Serological level of ICAM and ELAM adhesion molecules in allergic vascularitis.

A 24-patient lot with hypersensitivity vasculitis was investigated for serological determinations of ICAM and ELAM adhesion molecules. Determinations were made in attack and in remission. Over two thirds of the cases presented elevated serological levels of ICAM and ELAM in attack, with twofold higher values than normal. In remission, in the absence of clinical signs, ICAM and ELAM values were normal in 19 cases (ICAM) and 22 cases (ELAM). Serological level of ICAM and ELAM was concordant with serological level of IL-2, IL-6, circulating immune complexes and clinical status. The increased values of ICAM and ELAM are due to the expression of these molecules both on the surface of endothelial cells and on immune cells. The adherence of leukocytes on the endothelial cells, by adhesion molecules involvement, followed by their extravasation represents an important event in the vascular lesion pathogeny of the hypersensitivity vasculitis.

Adult↗
PubMedDate not supplied

Photodynamic treatment of basal cell carcinoma and squamous cell carcinoma with hypericin.

Hypericin displays antiproliferative and cytotoxic effects on tumor cells. This effect depends on photodynamic activation with visible light and oxygen. Hence, we explored its potential use in treating skin cancer. Eight patients with squamous cell carcinoma (SCC) and eleven patients with basal cell carcinoma (BCC) were treated topically with hypericin. After intralesional injection, the hypericin was irradiated with visible light. Patients with SCC were given 40-100 micrograms hypericin intralesionally, 3-5 times per week for 2-4 weeks; patients with BCC 40-200 micrograms hypericin 3-5 times per week for 2-6 weeks. Hypericin displayed selective tumor-targeting: penetration in the surrounding tissues did not induce necrosis or cell loss and even the generation of a new epithelium at the surface of the malignancy was noticed. The effectiveness of the therapy depends on the concentration and total dose of hypericin, the frequency and duration of the therapy; clinical remissions can be expected after 6-8 weeks.

Adult↗