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Biomedical subjects

J Barabás

Publications and source records attributed to J Barabás.

At least 19 recordsLinked to original sources
PubMed2002

Quadruple cancer, including triple cancers in the head and neck region.

Multiple primary tumors are not rare: they are encountered in 3-5% of malignant tumors. They are particularly frequent in the head and neck [20]. They are most often met with secondary malignant tumors; triple tumors occur in only 0.5%, quadruple tumors in 0.3% of malignant tumors. The possibility of developing a second metachronous cancer 5 years after undergoing treatment of the initial head and neck cancer is approximately 22%. Multiple metachronous tumors often appear 3-4 years after the observation of the primary tumor, or even after 5-10 years in the case of laryngeal tumors. The frequency of multiple primary tumors in the head and neck region supports the "field cancerization" theory, according to which the inducing agents (primarily smoking and alcohol consumption) can initiate the tumorous degeneration at a number of sites in the oropharyngeal region. The authors report on a case in whom surgery for bladder tumor was followed 101 months later by tumor development in the region of the head and neck: 3 such tumors were treated within a period of 21 months. The histologic result on the bladder tumor was transitiocellular carcinoma, while the latter ones were squamous cell carcinomas. Three of the tumors were treated effectively (no local recurrence or metastasis developed), but the fourth led to the death of the patient. The literature on multiple tumors of the head and neck is reviewed, and possible etiologic factors are discussed. It is pointed out that, besides primary and secondary prevention, close observation of these patients is required, repeated panendoscopy of the upper aerodigestive tract and genetic examinations are recommended.

Carcinoma, Squamous Cell↗
PubMed2000

Possibilities of preventing osteoradionecrosis during complex therapy of tumors of the oral cavity.

In recent years, there has been a dramatic increase in the number of tumors of the head and neck. Their successful treatment is one of the greatest challenges for physicians dealing with oncotherapy. An organic part of the complex therapy is preoperative or postoperative irradiation. Application of this is accompanied by a lower risk of recurrences, and by a higher proportion of cured patients. Unfortunately, irradiation also has a disadvantage: the development of osteoradionecrosis, a special form of osteomyelitis, in some patients (mainly in those cases where irradiation occurs after bone resection or after partial removal of the periosteum). Once the clinical picture of this irradiation complication has developed, its treatment is very difficult. A significant result or complete freedom from complaints can be attained only rarely. Attention must therefore be focussed primarily on prevention, and the oral surgeon, the oncoradiologist and the patient too can all do much to help prevent the occurrence of osteoradionecrosis. Through coupling of an up-to-date, functional surgical attitude with knowledge relating to modern radiology and radiation physics, the way may be opened to forestall this complication that is so difficult to cure.

Antineoplastic Agents, Alkylating↗
PubMed1999

Intra-arterial preoperative cytostatic treatment versus preoperative irradiation: A prospective, randomized study of lingual and sublingual carcinomas.

BACKGROUND: For several decades, both preoperative intra-arterial chemotherapy and preoperative irradiation have been accepted treatments for patients with tumors of the head and neck. Unfortunately, arguments have often been put forward in favor of one or other of the two methods, but without the performance of an objective, randomized investigation. To resolve this situation, the authors have carried out a multicenter, randomized prospective study of selected patients with a view to deciding which method affords better results in complex tumor therapy from the aspects of survival and postoperative quality of life. METHODS: One hundred thirty-one patients with operable sublingual or lingual squamous cell carcinoma in stages T2NXM0 to T4MXM0 were randomized into 2 groups: 1 group participated in preoperative chemotherapy with cisplatin and epirubicin (total doses: 200 mg cisplatin, 120 mg epirubicin) via the external carotid artery, whereas the other group received preoperative radiation therapy (46 grays). Following subsequent radical surgery, the patients received regular follow-up for 5 years. RESULTS: By the end of the 5 years, 95 of the 131 patients had conformed to the protocol. Of those 95, 47 had received preoperative chemotherapy and 48 preoperative irradiation. After 5 years, 18 of the 47 patients who received chemotherapy and 15 of the 48 patients who received irradiation were still alive and tumor free. A few more patients had died of recurrence or regional metastasis in the chemotherapy group (23 patients) than in the irradiation group (20 patients). Occurrence of a second carcinoma was 3 times as frequent in the irradiation group (9 patients) as in the chemotherapy group (3 patients). Overall, the survival rates were by-and-large the same for the two groups. Regarding postoperative quality of life, the chemotherapy group presented a more favorable picture. CONCLUSIONS: The long term survival results subsequent to preoperative intra-arterial chemotherapy or preoperative radiotherapy were practically the same. Regarding postoperative quality of life, patients who underwent intra-arterial chemotherapy appeared to be in a slightly more favorable situation. The authors consider it important to stress these findings, as they are not aware of a similar randomized study of patients with tumors of the oral cavity.

Adult↗
PubMed1999

A new advanced surface modification technique--titanium oxide ceramic surface implants: the background and long-term results.

This paper discusses the background of advanced surface modification technologies and presents a new technique that forms a titanium oxide ceramic coating with relatively long-term clinical use. Three general techniques are used to modify surfaces: adding or removing material, or changing material already present. Surface properties can also be changed through laser or electron beam thermal treatment without adding or removing material. The new technique outlined in this paper describes producing a corrosion-resistant, 2000 A to 2500 A thick, coherent crystalline oxide ceramic layer on the surface of titanium implants. The layer is grown electrochemically from the bulk of the metal and modified by heat treatment. Compared with implants covered with other coatings, the improved properties of such oxide ceramic-coated implants include the advantages of higher external hardness and greater adherence between the titanium and the ceramic oxide coating. The virtually perfect insulation between the tissue and the metal prevents metal allergy. The coated implants were subjected to various physical and chemical tests and electron microscopy for a qualitative characterization. Finally, these implants (plates, screws for maxillofacial osteosynthesis, and dental root implants) were followed in surgical practice for 10 years. Tests demonstrated and the acquired experience confirmed the good properties of the titanium oxide ceramic-coated implants.

Ceramics↗
PubMed1997

Use of Bioplant HTR synthetic bone to eliminate major jawbone defects: long-term human histological examinations.

This article describes the long-term follow-up of Bioplant HTR Synthetic bone (HTR: hard tissue replacement) in the human organism, as revealed by clinical, radiological and histological examinations and observations over a period of 5 years. Twenty-nine patients with lesions, 9 keratocysts, 16 radicular cysts, 3 traumatic cysts and 1 odontome were followed continuously during this period. All patients selected for follow-up had two criteria in common: the initial intervention had been performed at least 5 years previously; and the largest diameter of the bone defect was at least 2 cm. In all cases, when large bone defects were filled with HTR, the cavity was eventually filled with newly formed and remodelled bone. The process of ossification was relatively slow. In these cases, complete bony regeneration took up to 5 years. Ossification did not continue in the soft parts around the bone cavity. The histological pictures confirmed complete bone healing over the time.

Adolescent↗
PubMed1995

[Effectiveness of intra-arterial chemotherapy in the management of intra-oral cancers and their lymphatic metastases].

The effect of complex therapy (intra-arterial chemotherapy and radical surgery) on primary tumours and their metastases was studied in 38 oral squamous cell cancer cases. The therapy had different effect on the primary tumours and their lymph node metastases. There was a close correlation between the number of metastatic lymph nodes and survival. The extension and the chemotherapeutic regression rate of metastatic lesions showed a significant correlation with patients' survival.

Adult↗
PubMed1993

[Closure of cleft palate in adult patients, using a forearm flap with microvascular radial artery II].

A clinical report on the utilization of the so called "Chinese Flap" first published in 1981 is presented by the authors. The basic principle of this method is the following: After closing the soft palate in three layers, a mucoperiosteal flap has been prepared from the palatal mucosa and rotated into the nasal cavity so to close nasally the defect in one layer. Than a pediculated fasciocutaneous flap containing both the radial artery and the two comitantes veins prepared from the forearm was sutured to the defect. The a radialis and the v. comitantes running forward and downward between the two layers of the soft palate passing the mandibular ramus and descending through a tunnel leading to the submandibular region were joined to the facial artery and veins and an anastomosis was established. The clinical experience with the "Chinese Flap" procedure showed good results. This method has been used in 12 cases so far and only one out of the 12 failed due to blood vessel developmental abnormalities.

Cleft Palate↗
PubMed1993

[A case of hygroma of the neck].

The authors describe a case of cervical cystic hygroma in a young adult. The histological diagnosis of an operation performed two years earlier was erroneous. In this context they describe the pathology, occurrence and therapy of the disease.

Adolescent↗
PubMed1991

The clinical use of aluminium oxide bioceramic implants for mandibular condyle replacement: a six year report.

In a 6-year period, six bilateral and five unilateral compact aluminium oxide ceramic condyle fixed with titanium screws were implanted. During the years following the operation, it was not necessary to remove any ceramic condyle. In only one case (rheumatic polyarthritis) was it necessary to reoperate on the patient because of bilateral reankylosis. Ceramics can be recommended in a wide field application because of the simplicity, uniformity, durability, and good tissue-enduring ability. The danger of postoperative ankylosis occurs only in patients suffering from rheumatoid arthritis.

Adolescent↗
PubMed1990

Effect of aminoglycoside antibiotics on the autolytic enzyme of Streptomyces griseus.

The isolated cell wall of Streptomyces griseus 52-1 strain labelled with fluorescein isothiocyanate (FITC) and containing wall-bound autolytic enzyme was lysed as a function of different cations. The autolysis was accelerated by aminoglycoside antibiotics (streptomycin and the structurally closely related neomycin) which have a polycationic character. Since this strain is a streptomycin producer it is suggested that streptomycin may have a regulatory function on autolysis.

Amidohydrolases↗
PubMed1990

Application of compact aluminum oxide ceramic implants in maxillofacial surgery.

In a 4-year period, 40 compact aluminum oxide ceramic implants fixed with titanium plates and screws were used: 24 for the correction of mandibular defects, 9 for temporomandibular joint replacement, and 7 for augmentation of facial contour. During the 1 to 4 years following the operations, it was not necessary to remove any aluminum oxide joint or implant used for contour correction. In 5 of the 24 cases of mandibular reconstruction, however, it was necessary to remove the ceramic. In 3 cases, this was due to recurrence of the tumor, and in 2 cases the cause was dermal necrosis.

Adolescent↗
PubMed1990

In vitro investigation of BK-218, a new oral and parenteral cephalosporin.

The antibacterial activity of BK-218 was similar to that of cefamandole when it was tested against several laboratory strains. The inhibiting effect of BK-218 was greater than that of cephalexin and cefoxitin on penicillin-binding proteins of Escherichia coli HB101. This result was in close correlation with the relative inhibition of radiolabeled glucosamine incorporation (greatest with BK-218) and with the lytic effect (most intensive with BK-218). BK-218 proved to be a good inhibitor for all five of the beta-lactamases that were investigated, although two enzymes (Enterobacter cloacae P99 and Pseudomonas aeruginosa Cilote) hydrolyzed it to some extent.

Bacteria↗