Theoretical and experimental evidence of extinction and coexistence of killer and sensitive strains of yeast grown as a mixed culture in water.

Theoretical and experimental evidences of extinction and coexistence during batch interaction of killer and sensitive strains of Saccharomyces cerevisiae grown as a mixed culture in pure water are provided. The experimental results show that in the limited nutrient conditions of growth in pure water, the killer yeast is subject to extinction when the initial concentration ratio of killer to sensitive yeast is 1:100. However, if the initial concentration ratio of killer to sensitive yeast is 1:1, both strains coexist. Substantial damped oscillations are associated with the growth process in the mixed culture. A new theoretical model that was originally developed for recovering the growth of single species in isolation is extended and applied to two species competing over a common ecological niche. The solutions of the model are shown to recover all the qualitative features captured in the experiments.

Recovery of an oscillatory mode of batch yeast growth in water for a pure culture.

New experiments that we conducted show an oscillatory mode of batch yeast growth in water, for a pure culture of the T206 strain of Saccharomyces cerevisiae. The oscillations are damped over time, allowing the cell concentration to stabilize at the stationary equilibrium. A new proposed model that includes the complete cell growth dynamics is introduced and showed to recover the experimental oscillatory results. In addition the proposed model recovers effects that are frequently encountered in experiments such as a "Lag Phase" as well as an inflection point in the "ln curve" of the cell concentration. The proposed model recovers also the Logistic Growth Curve as a special case. For purposes of providing some interesting contrast we present additional experimental as well as computational results for the growth of the VIN7 strain of S. cerevisiae in a 5% grape juice medium. The latter indicates even stronger oscillations during the growth process. In order to capture experimentally the oscillatory growth behavior, very frequent readings are required (every 15-30 min) and the measurement process needs to be extended to longer than usual periods (over 250 h).

Role of occupational asbestos exposure in Hungarian lung cancer patients.

OBJECTIVE: What is the frequency of occupational asbestos exposure among patients suffering from malignant respiratory tumours and how many of these tumours are associated with asbestos in Hungary? METHODS: An internationally established questionnaire with 29 questions, covering the most characteristic activities of asbestos exposure at the workplace was completed for 300 patients with respiratory malignancies, i.e. 297 patients with lung cancer and three with mesothelioma of the pleura. From the questionnaire, the smoking habits were estimated and cumulative asbestos exposure was assessed in fibre-years. Additionally, lung X-rays were classified and the national data on the incidence of malignant pleura mesothelioma were analysed. RESULTS: A cumulative asbestos exposure of 25 fibre-years or more was detected in 11 patients with lung cancer (4%) and in each of the three patients with pleural mesothelioma (100%). In a further 72 patients (24%), cumulative occupational asbestos exposure was assessed as below 25 fibre-years (between 0.01 and 23.9 fibre-years). In this group, car and truck mechanics, and installation and construction workers using asbestos-cement were registered. Among patients with an asbestos exposure of 25 fibre-years or more, six asbestos-cement production workers were observed, among them the three mesothelioma cases. A weak but significant association between positive X-ray findings and exposure estimates could be demonstrated. Additionally, results of the lung tissue fibre counts by scanning transmission electron microscopy were available for 25 of the lung cancer patients. A good correlation was observed between the asbestos fibre counts and the assessment of cumulative asbestos exposure. In Hungary, 84 cases of pleural mesothelioma were registered in 1997 and 73 in 1998. These numbers correspond to an annual incidence of about one new case per 100,000 inhabitants older than 15 years. CONCLUSIONS: The annual incidence of lung cancer in Hungary is about 6,000. Since in our series of lung cancer patients about 4% were observed, which could be accepted as representing occupational disease because of a cumulative exposure to 25 fibre-years or more, the annual asbestos related lung tumour incidences may be estimated to be approximately 150 or more. The proportion of nearly two estimated cases of lung cancer per case of pleural mesothelioma corresponds to international experience. Up to now, lung cancer cases only exceptionally have been registered as occupational diseases, i.e. they were seriously under-diagnosed in Hungary. For improving this situation, diagnostic assistance by a self-interview with a questionnaire covering the working history for all newly diagnosed lung cancer patients would be helpful.

Mucoepidermoid bronchial tumors: a review of 34 operated cases.

OBJECTIVE: Pulmonary mucoepidermoid tumors are commonly included with adenoid cystic carcinoma and carcinoid tumors under the misleading rubric 'bronchial adenomas'. These neoplasms are extremely rare and little is known about their oncologic behaviour. They are considered to be of high, or low malignancy. METHODS: During a 16-year-period 34 consecutive patients (24 male and 10 female with an average age of 53 years) underwent surgery for pulmonary mucoepidermoids in our clinic (0.5% of all resected lung tumors). Fourteen patients were complaint free, in the others obstructive symptoms dominated. In 23 patients the tumors were located in the upper lobes. In 24 cases lobectomy, in four instances limited resection and in six cases pneumonectomy were performed without hospital mortality. RESULTS: Twenty-nine tumors proved to be high grade and five low grade malignancy by histology. In the latest group the 5-year-survival amounted to 80% (all of these tumors were observed in stage T1-2 N0), on the other hand, however, that rate accounted only 31% at high grade malignant mucoepidermoids. There was no 5-year-survivor among patients having N2-disease (n=5). CONCLUSION: Mucoepidermoid tumors have to be treated by radical surgery with lymph node sampling and dissection. Patients with low grade tumors can be expected to be cured following complete resection, on the other hand, however, in cases of high grade malignant neoplasms surgery results in significantly worse prognosis. Careful histological typing plays a key role in prediction of late results.

Radicality and prognosis of surgical treatment of thoracal carcinoid tumors: a review of 152 operated cases.

BACKGROUND: Experience of thoracal (bronchial and thymic) carcinoid tumors is discussed to add some remarkable diagnostic and therapeutic details for their treatment, based on a retrospective clinico-pathological analysis of 152 consecutive patients operated on at the Thoracic Surgery unit in Budapest between 1974 and 1988. METHODS: Prior to surgery 70 patients were symptom free, obstructive symptoms dominated in 65 patients, and hemoptysis occurred in 23 cases. In 68 patients a peripheral coin lesion was visible in radiographs and in 81 cases the tumor could be seen by bronchoscopy. In 3 patients the neoplasm appeared as mediastinal thymic-carcinoid. Pathological confirmation was based on routine light-microscopic sections, Grimelius technique, and immunohistochemical stainings for NSE and chromogranin. Bronchoplastic procedures were performed in 28 patients and limited (wedge or segmental) resection in 21 cases. RESULTS: Atypical carcinoids were diagnosed in 18 cases, microscopic vascular invasion could be seen in 70 tumors (46%), and 12 patients had a single hilar lymph-node metastasis. Immunostaining for NSE was evident in all carcinoids and 82% of the tumors presented positive reaction for chromogranin staining. Hospital mortality was 1.3%. The 5-year-survival rate amounted to 93% and the 10-year-survival rate to 83% (126/ 152). The early postoperative deaths were among 49 patients operated on by parenchyma-sparing methods; the rest of these 49 are alive and free of symptoms. Local recurrence occurred after a lobectomy and following removal of a mediastinal carcinoid. The tumors of 23 of the 26 dead patients showed vascular invasion, but 19 neoplasms among them had neither atypia nor regional lymph-node involvement. In the group of patients having tumors with signs of microscopic vascular invasion the 10-year-survival rate was 67%, while in the others it amounted to 96%. CONCLUSIONS: Bronchial carcinoids require anatomic resection with lymph-node dissection. On the other hand, however, parenchyma-sparing methods have to be encouraged because of excellent late results. In our experience, immunohistochemistry for chromogranin can give some help in separation on the neuroendocrine tumor scale, and the presence of microscopic vascular invasivity is the main prognostic factor.

Surgical aspects of 175 mediastinal goiters.

OBJECTIVE: Clinical picture and surgical management of 175 mediastinal goiters are discussed in this retrospective study. METHOD: Between 1979 and 1996, 175 patients with intrathoracic goiters were operated on at the Thoracic Surgical Clinic in Budapest. The majority of the goiters were cervicomediastinal (n = 138, 79%), past the level of aortic arch, and the others were complete aberrant lesions (n = 37, 21 %). Of the patients, 40% (n = 70) were symptom-free, in the others the clinical picture was dominated by compressive symptoms, among them, in five instances, the initial false, long-lasting diagnosis was bronchial asthma and, in four cases, vena cava superior syndrome caused by advanced inoperable malignancy. Twenty-two percent of patients (n = 39) were operated on previously for cervical struma. Eleven percent (n = 19) of the patients had hyperthyroid symptoms. In 124 cases the goiters were located in the anterior mediastinum. The majority (n = 96) of cervicomediastinal goiters (n = 138) could be removed through a cervical access, in the others an additional sternotomy (n = 31), or anterior thoracotomy (n = 11) were necessary. For resection of complete intrathoracic goiters (n = 37) standard thoracotomy (n = 30) or median sternotomy (n = 7) were used guided by retrotracheal or substernal position. RESULTS: Hospital mortality was 1.1%. Minor complications occurred in 46 cases (26%) and laryngeal nerve palsy in 14 patients (8%). Tracheomalatia developed in 18 patients (10%) which were mainly solved by tracheal intubation for 4-6 days. Ninety-four percent (n = 165) of the lesions proved to be diffuse colloid or adenomatous goiters by histology and 10 were (mostly follicular type) carcinomas. CONCLUSIONS: Unrecognized mediastinal goiters can produce asthma like symptoms, which may lead to late or misdiagnosis and deficient treatment. Once the diagnosis and exact extent of mediastinal goiter is established, multimodal surgical approaches are indicated for its safe removal - before occurrence of compressive symptoms.

Management of malignant tracheoesophageal fistulas with a cuffed funnel tube.

BACKGROUND: A detachable cuffed flange tube for the assessment of malignant tracheoesophageal fistulas by a minimal invasive surgical insertion technique is presented. The funnel cuff of this tube seals the space between the esophageal wall and the flange of conventional tubes above the fistula at the level of the suprastrictural dilatation. METHODS: Twenty-eight patients having a malignant esophagorespiratory fistula with associated primary or secondary esophageal stricture, except 1, underwent esophageal intubation with this prosthesis between 1983 and 1996. RESULTS: All insertion attempts, without previous esophageal dilation, were successful. The overall mortality was 7.4%. The cuffed funnel has provided hermetic water-tight exclusion of the fistula in all instances. Intraabdominal septic complications, reflux, or tube displacement have never occurred after use of this intubation technique. CONCLUSIONS: For occlusion of malignant respiratory tract fistulas this cuffed flange tube proved to be superior to conventional esophageal prostheses.

Transdiaphragmatic cyst-jejunostomy with Roux-en-Y loop for an exclusively mediastinal pancreatic pseudocyst.

In a patient presenting with a roentgenographic retrocardiac density, left pleural effusion and distal oesophageal displacement, echocardiography confirmed presence of a pseudocyst in the posterior mediastinum. Pancreatic origin was suspected. Left thoracolaparotomy revealed the large (900 ml), exclusively mediastinal pseudocyst, surrounding the aorta and adherent to the diaphragm, with high amylase content. Decompression was achieved with a retrocolic and gastric Roux-en-Y loop by transdiaphragmatic cystojejunostomy.

[Early diagnostic pitfalls in esophageal perforation and spontaneous rupture of the esophagus]. / A korai diagnózis útvesztöi nyelöcsö-perforációkban és spontán nyelöcsörupturákban.

In this retrospective study (1981-1993) of 31 cases of esophageal perforations and ruptures circumstances the delay or misdiagnosis with undoubtable influence on the survival have been discussed. The over-all mortality was 16.1% but in cases of early (24 h) perforations or ruptures (12) no patients were lost. The unfavourable consequence of the superficial case history, underestimated pain, incomplete roentgenographic study, diagnostic confusion inadequate surgical exploration and misinterpreted postoperative complications of the formal esophageal surgery are analyzed. The authors emphasized the methods to decrease the number of the false-negative contrast esophagograms as well as the value of the intraoperative endoluminal diluted methylin-blue injection to detect esophageal leak. The early diagnosis is the first prerequisite for a favourable outcome in this life-threatening emergency.

[Minimally invasive thoracic surgical procedures. Experience with standard video-thoracoscopic and mini-thoracotomy methods]. / Minimálisan invazív mellkasi mütétek. Tapasztalataink a standard video-thoracoscopos és mini-thoracotomiás módszerrel.

Experiences based on 75 minimal invasive intrathoracic procedures performed during a one and half--year--period are reported. The standard video thoracoscopic and mini-thoracotomy methods are compared. The possible indications are discussed, and the authors' opinion about the role of these methods in pulmonary resections is presented. They call attention to the consideration of the limits and possibilities of this new technique.

[Possibilities and limitations of minimally invasive methods in thoracic surgery]. / A "minimal invasive" mütéti irányzat lehetöségei és korlátai a mellkassebészetben.

First experiences with minimal invasive thoracic surgery are presented. Between November 1991 and September 1992 37 intrathoracic operations--3 lobectomies among them--have been performed by their modified method. A special surgical thoracoscope was inserted through a 6-7 cm-s incision into the thorax. This instrument provides a direct view with excellent distal illumination and it also can be applied by video-thoracoscopic system. It is emphasized that their method needs further development. It's practical value and result depend on the appropriate consideration of possibilities and limits, and on careful selection of the patients.

Diagnosis and treatment of bronchial carcinoid tumors: clinical and pathological review of 120 operated patients.

Clinical and pathological review is presented of 120 patients operated on for bronchial carcinoid tumors between 1976 and 1986. The usual oncologic features were analyzed. The Grimelius reaction, immunohistochemical staining for neuron specific enolase (NSE), serotonin and chromogranin, and DNA-analysis by flow cytometry were performed in these tumors and in small cell lung cancers (SCLC). In our experience the usual oncologic criteria--atypia, tumor-size, localization, history and regional lymph node metastasis--fail to give clear information for the prognosis. The Grimelius reaction has no significant differential diagnostic importance. Immunostaining for NSE can aid in distinguishing between neuroendocrine and non-neuroendocrine pulmonary tumors. The carcinoids and SCLCs could be differentiated by immunostaining for chromogranin and by flow cytometry but none of these methods are suitable for differential diagnosis within the carcinoid group. Resection by thoracotomy is the only treatment of choice: it can provide an excellent result (the 5-year survival rate is above 90%) with a low hospital mortality (0.8%). Parenchyma-sparing resections are to be encouraged.

[Surgical management of mediastinal tumors based on experience with 1000 cases]. / Ezer gátori daganat sebészi kezelésével szerzett tapasztalataink.

One thousand operated mediastinal tumours are analysed. Their characteristic features are discussed and some uncommon manifestations are presented. It is emphasized that in most cases (80-90%) the traditional simple X-ray methods can give a sufficient information for the diagnosis. On the other hand, vascular lesions, cervicomediastinal goiters, dumbbell neurinomas, lymphatic diseases and esophageal lesions should be detected carefully by especial diagnostic methods before surgery because of the different operative tactics and consequences. The diagnosis of the mediastinal neoplasm indicates surgery due to their compressive behaviour.

[Reoperation in thoracic outlet syndrome]. / Vállövi alagút (thoracic outlet) szindróma miatt végzett reoperációk.

Questions of surgical treatment are dealt with shortly when analyzing reoperations in cases of thoracic outlet syndrome. Transaxillary first rib resection is considered as a favourable solution. Authors believe that in the overwhelming majority of recurrences it is the lack of resection or insufficient resection of the first rib that can be considered as responsible for it. By the way of conclusion the importance of medical gymnastics and physiotherapy to be started in the early postoperative period is pointed out.

[Severe tracheal compression caused by achalasia]. / Achalasia okozta súlyos trachea-kompresszió.

A very rare complication of achalasia (cardiospasm) is presented. In the authors' case the esophagus of a 15-year old girl was dilated to a great extent and caused through the compression of the trachea upper respiratory obstruction. Following the surgical solution of the achalasia the respiratory complications ceased too. Attention is drawn to the possibility that esophagus diseases may play a significant role in the etiology of different pulmonary diseases.

Anastomoses of the colon made by inverting sutures.

The authors report on the advantages of inverting suture in the anastomoses of the colon. The comparative evaluation of the stapler gun technique and the sleeve technique is presented.

Oesophageal, gastric and small bowel anastomoses made by the sleeve technique.

The authors report on their experiences in oesophageal, gastric and small bowel anastomoses made by inverting sutures. The technique of constructing the anastomoses is described with an emphasis on the necessity of considering the sizes and proportions. The advantages of the method are summarized and the operations performed so far are presented.