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Biomedical subjects

R Pavelka

Publications and source records attributed to R Pavelka.

At least 19 recordsLinked to original sources
PubMed1996

Conventional vs accelerated fractionation in head and neck cancer.

From October 1990 to March 1994, 90 patients entered a prospectively randomised trial in head and neck cancer. All patients had verified squamous cell carcinoma and were referred for primary radiation therapy. Tumours originated in the oral cavity in 25, oropharynx in 37, larynx in 15 and hypopharynx in 13 cases. Patients' stages were predominantely T3 and T4 (71/90) and had lymph node metastases (60/90). Seventy-nine male patients and 11 female patients, with a median age of 57 years (range 37-76 years) were treated. Patients were randomised to one of three treatment options: conventional fractionation (CF) consisting of 70 Gy in 35 fractions over 7 weeks or continuous hyperfractionated accelerated radiation therapy (Vienna-CHART) or Vienna-CHART with administration of a single dose of mitomycin C on day 5 of treatment (V-CHART + MMC). By the accelerated regimen a total dose of 55.3 Gy was given in 33 fractions within 17 consecutive days. Acute mucositis was the main toxicity recorded in those patients treated by accelerated fractionation, although the overall duration of mucosal reaction did not differ in the three treatment groups. There was no influence on local toxicity if MMC was added to radiation therapy or not. Those patients treated with additional MMC experienced a grade III/IV haematological toxicity in 4/28 cases. Complete remission (CR) was recorded in 48% following CF, 79% after Vienna-CHART (P < 0.05) and 71% after Vienna-CHART + MMC. The overall local failure rates were 73%, 59% and 42% (P = NS) for patients treated by CF, Vienna-CHART and Vienna-CHART + MMC respectively.

Adult↗
PubMed1992

[Atypical fractionation in advanced squamous-cell carcinomas of the head-neck area].

From May 1990 to May 1991, 23 patients with advanced, inoperable squamous cell cancers, clinically staged as III or IV, were treated by unconventional fractionation radiotherapy. Treatment consisted of a continuous hyperfractionated accelerated radiotherapy, delivering a total dose of 55.3 Gy within 17 consecutive days. In ten patients radiation therapy was combined with chemotherapy; 20 mg mitomycin C/m2, administered by intravenous bolus injection on day 5 of treatment. Apart from a confluent mucositis, treatment tolerance was good. Haematological toxicity from mitomycin C was minor and did not require any specific therapy. The mucosal reaction lasted six weeks (median duration) and was not thought to be increased by additional chemotherapy. In twelve of 23 patients a complete remission of the primary tumour was seen, in patients with lymph node metastases there was a complete response in 14 out of 20 patients. After a median follow-up of 18 months, ten of 23 patients have survived (8/23 without evidence of disease). Eleven patients have died due to local tumour progression and one patient died with distant metastases, being without evidence of local tumour. The advantage of this unconventional fractionation, which takes the described short potential tumour doubling time for head and neck cancers into account, is discussed.

Adult↗
PubMed1991

Determination of small drug molecules by capillary electrophoresis-atmospheric pressure ionization mass spectrometry.

Capillary electrophoresis (CE) separations are reported for sulfonamides and benzodiazepines in an uncoated fused-silica capillary. The capillary column exit was connected to a liquid junction-ion spray interface combination coupled to an atmospheric pressure ionization (API) triple quadrupole mass spectrometric (MS) system. On-line UV detection occurred 20 cm from the inlet of the capillary and with the API mass spectrometer (CE-API-MS) after the entire length of the capillary (100 cm). The separations were made using volatile buffers composed of ammonium acetate (15-20 mM) with 15-20% of methanol to facilitate ionization under electrospray conditions. This study showed that the major metabolite of flurazepam in man, N-1-hydroxyethylflurazepam, could be detected and characterized in human urine by CE-UV-MS following the administration of a single oral dose of 30 mg of flurazepam dihydrochloride. The presence of additional flurazepam metabolites in human urine was observed by using the system, suggesting that a combination of UV with MS detection should be useful for metabolic studies. In addition to molecular weight determination of compounds, structural information may be obtained by utilizing online tandem mass spectrometry (CE-UV-MS-MS). This was demonstrated for sulfamethazine where the protonated molecule species was transmitted into the collision cell of the tandem triple quadrupole mass spectrometer. Collision-induced dissociation of the protonated sulfamethazine molecule yielded structural information characteristic of the sulfa drug following the on-column injection of 2 pmol of sulfamethazine.

Benzodiazepines↗
PubMed1990

[Sonography in malignant tonsillar tumors].

In this retrospective study the value of sonography in the preoperative staging of malignant tumours of the tonsils was evaluated in 36 patients. According to our results sonography is indicated in small tumours. In greater tumours, especially if bone destruction could be expected, MR or CT should be performed additionally to sonography. Good results were achieved in assessing the infiltration of the tongue with or without crossing the midline (accuracy 92 to 97%) and the detection of cervical lymph node metastasis (accuracy 94%).

Adult↗
PubMed1989

Advanced laryngeal cancer: sonographic assessment.

Endoscopy permits visualization of the endolaryngeal spread of laryngeal tumors, yet the depth of tumor infiltration often remains unclear. The authors used high-resolution sonography in 37 patients with advanced laryngeal cancer to assess the tumors and the cervical lymph nodes. Sonographic findings were compared to operative and histologic reports. Sonography demonstrated histologically confirmed infiltration into the thyroid (n = 8) and cricoid cartilages (n = 1), preepiglottic space (n = 12), base of the tongue (n = 4), hypopharynx (n = 8), subglottic space (n = 3), and thyroid gland (n = 2). Except for the retrolaryngeal portion of the tumor, sonography was valuable in assessing extralaryngeal spread of advanced cancers. It enabled detection of subclinical lymph node metastases in four patients. Furthermore, invasion of the wall of the carotid artery was found in two patients. For evaluating the endolaryngeal and hypopharyngeal portions of the tumor, endoscopy remains mandatory.

Female↗
PubMed1988

[CT staging of laryngeal carcinoma].

In the pre-operative staging of laryngeal carcinoma CT is of great clinical importance. We examined 20 cases of laryngeal cancer. In 20% of the cases, the CT evaluation indicated more advanced stages, thereby correcting the results of clinical staging. In 65% of the cases, clinical staging showed the same results as CT. 3 glottis tumours (15% of the patients) could not be identified by CT.

Adult↗
PubMed1987

Tongue cancer. Sonographic assessment of tumor stage.

In an effort to improve preoperative evaluation of tumors of the tongue, a prospective study on the value of ultrasound (US) for the staging of 50 surgically proven cancers of the tongue and floor of mouth was performed. Sonography was correlated with clinical staging and surgical outcome. Real-time high-frequency transducers and an echo-free silicone interface were used. The dorsal and middle thirds of the tongue were scanned from a submental access and the tip of the tongue directly. US accurately defined tumor sizes and locations in all cases. US staged cancers correctly in all cases but one. In contrast, clinical staging was correct in only 66% of cases. Surgically relevant details, such as crossing of the midline of the tongue or infiltration of the lateral pharyngeal wall, were detected with US. The major limitations of US include the nonvisualization of the epiglottis and retropharyngeal space as well as bone infiltration.

Female↗
PubMed1986

Electron beam therapy in treatment of parotid neoplasm.

In a retrospective analysis, 42 patients with malignant primary tumor of the parotid gland were evaluated considering survival, local recurrence and tolerance of treatment. All patients referred to radiotherapy were treated by electron beam (10-15 MeV) and followed for more than 5 years. Postoperative radiotherapy after radical operation, with no macroscopic disease, was performed in 18 patients, 7 of whom were treated by radical re-operation and radiation of a recurrent parotid neoplasm. In these groups, the local recurrence rate was 4/18 (22%) and 2/7 (29%), the 5-year survival rate was 9/18 (50%) and 5/7 (71%). In 17 patients, radiotherapy started with gross tumor left behind. This group showed a local recurrence rate of 10/17 (59%) and a 5-year survival of 7/17 (41%). Treatment was well tolerated with no major sequelae. Local tumor control and its impact on survival is discussed.

Adult↗
PubMed1986

[Realtime sonography in the diagnosis and follow-up of malignant tongue tumors. II. Detection and staging].

92 sonographic examinations performed in 62 patients were evaluated to determine the possible application of sonography in the diagnosis and follow-up of malignant tumours of the tongue. Squamous cell carcinomas were by far dominant and proved to be hypoechoic, mainly inhomogeneous and ill-defined masses. In most cases, they ranged between 2 and 4 cm. in diameter. In 50% of the lesions an infiltration of the pharynx wall was confirmed, and exulcerations were correctly detected by sonography in 75%. In preoperative determination of the size of the tumour, sonography correctly detected the size in 93% of the cases and was thus markedly superior to the clinical palpatory examination, which determined a mere 43% correctly. Sonography should be included in the pretherapeutic staging of tumours of the tongue to objectify the clinical findings. It is also adequate to document tumour behaviour during radiation.

Aged↗
PubMed1986

Serum immunoglobulin levels in patients with head and neck cancer (IgE, IgA, IgM, IgG).

In the present study, 226 patients with squamous cell cancer of the head and neck, who had had undergone no antitumor therapy, were examined pretherapeutically for serum immunoglobulin levels (IgG, IgM, IgA, IgE). In cancer patients, significant elevations of mean levels of IgA and IgE were found in comparison to healthy controls (n = 100) and patients with chronic laryngitis (n = 63). IgG and IgM were in the range of the control groups. Levels above the upper limit were detected in 40.9% for IgE and 43.9% for IgA in the groups of cancer patients and in about 6% for both immunoglobulins in the control group. The group of patients with relapses in the follow-up were found to have pretherapeutically significantly higher levels of both IgE and IgA in comparison to those without evidence of disease for more than 6 months. These results point to the fact that determination of serum IgA and IgE levels in patients with head and neck cancer might be applicable as parameters for monitoring malignant disease, being additionally of some prognostic significance.

Antibody Formation↗
PubMed1986

[Radiotherapy of carcinoma of the paranasal sinuses].

Carcinomas of the paranasal sinuses are usually advanced when diagnosed and present a therapeutic challenge. During the period between February 1970 and June 1981 44 patients were treated. 22 received postoperative irradiation, seven in combination with chemotherapy. 18 patients were treated with radiation alone, eleven with concomitant chemotherapy. Four patients received preoperative irradiation, three in combination with chemotherapy. The three-year survival is 43% and the five-year survival 33%. For those 26 patients who were irradiated pre- or postoperatively with or without concomitant chemotherapy the five-year survival is 45%. We believe the patient will be afforded the greatest opportunity for cure with the combined efforts of the radiotherapist and the surgeon. The combination of chemotherapy and radiotherapy did not provide better results but increased acute and chronic toxicity of the therapy.

Adult↗
PubMed1986

Sonography of the tongue and floor of mouth. Part II: Neoplasms of the tongue.

Frequently, correct evaluation of space-occupying lesions in the tongue is not possible with clinical methods only. In an attempt to assess the value of sonography in the detection of tongue lesions, we used submental sonography to examine 62 patients with suspicious palpatory findings upon physical examination of the tongue. Ultrasound detected 45 out of 47 tumours that were eventually confirmed either by surgery or by biopsy. Inadequate technique was the only factor that affected the detection rate. Sonography appears to be a reasonable guide in determining size and site of a tumour of the tongue. Thus, more precision in therapy planning may be achieved.

Aged↗
PubMed1986

[Evaluation of real-time sonography in the pretherapeutic staging of malignant tumors of the tongue and mouth floor].

Based on our three years experience with about 200 transcutaneous real-time sonographies of the tongue and the floor of mouth, an assessment of the determination of size and site of 38 pretherapeutically examined malignant tumours (35 squamous cell carcinomas) was made. The patients were examined in reclined position, the head retroflected. Curved array transducers of 5 or 7.5 MHz and a silicon elastomer block as interface turned out to be optimal. All tumours could be detected by sonography as hypoechoic, more or less homogeneous, ill-defined areas. Two thirds of the tumour ulcerations could be seen as hard hyperechoic reflexes within the hypoechoic areas. When comparing the maximal diameter of tumours of the 20 operated patients, we found an agreement (5 mm tolerance) of sonography with the surgical specimen in 14 of 20 tumours (70%), of sonography with the clinically estimated diameter in 10 of 20 tumours (50%), whereas the clinically estimated diameter was in agreement with the surgical specimen in only 8 of 20 tumours (40%). A peritumoral inflammatory infiltration can simulate a larger tumour size in sonography. The extent of tumours within the tongue, to the floor of mouth, the lateral pharyngeal wall and the preepiglottic space was documented correctly in most cases. In three cases a previously unknown spread across the midline was found sonographically. Including the sonographic findings in the TNM classification, 5 T1 tumours would have been staged as T2 and one T3 tumour as T4. Inflammatory diseases of the tongue can show the same sonomorphology as malignant tumours.

Adult↗
PubMed1985

[Immunoglobulin A serum antibodies against the capsid antigen of Epstein-Barr virus in the differential diagnosis and follow-up of nasopharyngeal cancer].

IgA antibodies to Epstein-Barr virus capsid antigen (IgA anti-VCA) can be detected in sera of patients with certain types of nasopharyngeal carcinoma (NPC). IgA anti-VCA titres were determined by the indirect immunofluorescence technique. 17 control patients with benign diseases or carcinomas of the head and neck other than NPC had negative IgA anti-VCA titres less than or equal to 1:16. NPC was diagnosed histologically according to the Cologne modification of the WHO classification. Among 16 cases of untreated or recurrent NPC, a rare disease in Europe, seen over the past three years, those with undifferentiated carcinomas with and without lymphoid stroma and the non-keratinizing carcinomas with lymphoid stroma were IgA anti-VCA positive (1:32 to 1:512), whereas patients with squamous cell carcinomas were negative. In four cases the primary tumour had not been diagnosed by other ENT doctors in spite of known regional or distant metastases consisting of undifferentiated carcinomas with or without lymphoid stroma. IgA anti-VCA antibodies in the sera of these patients indicated the probable site of the primary tumour. NPC was verified by biopsy in all these cases. In 2 serologically negative patients the original diagnosis of undifferentiated NPC with lymphoid stroma had to be revised to malignant Non-Hodgkin lymphoma. In the follow-up of 6 NPC patients the trend of changes in IgA anti-VCA titres correlated with the course of the disease, but the minute tumour-related changes could be detected only when at least two previous sera of the same patient were included in every test.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Viral↗
PubMed1985

Recombinant interferon-alpha-2C in laryngeal papillomatosis: preliminary results of a prospective multicentre trial.

A preparation of interferon-alpha 2C of high purity formed by recombinant DNA technology was used as adjuvant therapy following removal of laryngeal papillomas by cauterization or laser vaporization. Preliminary data on 20 patients are reported and include 11 complete and 7 partial responses. Side-effects included initial temperature elevation, but this subsided and other side-effects were uncommon. No antibodies to the interferon preparation were found in any of the patients.

Clinical Trials as Topic↗