Surface expression of the immunotherapeutic target GD2 in osteosarcoma depends on cell confluency

BACKGROUND

Chimeric antigen receptor (CAR) T-cell therapy of pediatric sarcomas is challenged by the paucity of targetable cell surface antigens. A candidate target in osteosarcoma (OS) is the ganglioside GD2 , but heterogeneous expression of GD2 limits its value.

AIM

We aimed to identify mechanisms that upregulate GD2 target expression in OS.

METHODS AND RESULTS

GD2 surface expression in OS cells, studied by flow cytometry, was found to vary both among and within individual OS cell lines. Pharmacological approaches, including inhibition of the histone methyltransferase Enhancer of Zeste Homolog 2 (EZH2) and modulation of the protein kinase C, failed to increase GD2 expression. Instead, cell confluency was found to be associated with higher GD2 expression levels both in monolayer cultures and in tumor spheroids. The sensitivity of OS cells to targeting by GD2 -specific CAR T cells was compared in an in vitro cytotoxicity assay. Higher cell confluencies enhanced the sensitivity of OS cells to GD2 -antigen specific, CAR T-cell-mediated in vitro cytolysis. Mechanistic studies revealed that confluency-dependent upregulation of GD2 expression in OS cells is mediated by increased de novo biosynthesis, through a yet unknown mechanism.

CONCLUSION

Expression of GD2 in OS cell lines is highly variable and associated with increasing cell confluency in vitro. Strategies for selective upregulation of GD2 are needed to enable effective therapeutic targeting of this antigen in OS.

Overcoming Heterogeneity of Antigen Expression for Effective CAR T Cell Targeting of Cancers

Chimeric antigen receptor (CAR) gene-modified T cells (CAR T cells) can eradicate B cell malignancies via recognition of surface-expressed B lineage antigens. Antigen escape remains a major mechanism of relapse and is a key barrier for expanding the use of CAR T cells towards solid cancers with their more diverse surface antigen repertoires. In this review we discuss strategies by which cancers become amenable to effective CAR T cell therapy despite heterogeneous phenotypes. Pharmaceutical approaches have been reported that selectively upregulate individual target antigens on the cancer cell surface to sensitize antigen-negative subclones for recognition by CARs. In addition, advanced T cell engineering strategies now enable CAR T cells to interact with more than a single antigen simultaneously. Still, the choice of adequate targets reliably and selectively expressed on the cell surface of tumor cells but not normal cells, ideally by driving tumor growth, is limited, and even dual or triple antigen targeting is unlikely to cure most solid tumors. Innovative receptor designs and combination strategies now aim to recruit bystander cells and alternative cytolytic mechanisms that broaden the activity of CAR-engineered T cells beyond CAR antigen-dependent tumor cell recognition.

Cryptococcal meningitis presenting as sinusitis in a renal transplant recipient

Cryptococcal meningitis is a relatively common invasive fungal infection in immunocompromised patients, especially in solid organ transplant recipients. Clinical presentation typically includes fever, headache, photophobia, neck stiffness, and/or altered mental status. Unusual presentations may delay diagnosis. Therapy is challenging in renal transplant patients because of the nephrotoxicity associated with amphotericin B, the recommended treatment. We present a case of cryptococcal meningitis in a renal transplant recipient presenting as acute sinusitis with successful treatment using fluconazole as primary therapy.

[Postoperatively increased oxygen demand and hemoptysis after extubation]

A 22-year-old man on postoperative day 1 after open reduction with internal fixation of a distal fibula fracture presented with hemoptysis and increased oxygen demand. X-ray and contrast-enhanced computed tomography revealed bilateral patchy opacities and mediastinal emphysema. After bronchoscopy and bronchoalveolar lavage, a diagnosis of alveolar hemorrhage was made. The medical history revealed regular abuse of marihuana and cocaine.

[Dyspnea in a 45-year-old man with liver cirrhosis]

HISTORY AND ADMISSION FINDINGS

During evaluation for a liver transplantation in a 45-year-old man with alcoholic liver he complained of exertional dyspnea. He had grade 3 chronic obstructive pulmonary disease (COPD) after nicotine abuse of 50 pack-years. One and a half years earlier the patient had been treated for tuberculosis.

INVESTIGATIONS

The diagnostic procedures showed a respiratory insufficiency with a PO(2) of 52 mm Hg. Notable was a missing improvement of oxygenation after the supply of 100 % oxygen. Lung perfusion scintigraphy showed a shunt of about 14 %, a contrast-medium echocardiography demonstrating a right-to-left shunt. These findings indicated that the patient had a hepatopulmonary syndrome.

TREATMENT AND COURSE

The only causal therapy of a hepatopulmonary syndrome was a liver transplantation. However, the tuberculosis diagnosed one and a half years earlier had not been treated adequately, so that an antituberculotic therapy was essential before starting an immunosuppression. Therefore the only option of treatment was to continue the long-term oxygen therapy. As a matter of differential diagnosis and because of the intrapulmonary shunt, a pulmonary venous disconnection for a shunt caused by tuberculous cavities or by the COPD had to be taken into account.

CONCLUSION

Treating patients with advanced liver cirrhosis and dyspnea a hepatopulmonary syndrome must be taken into consideration. Typically there will be found a right-left-shunt. In addition, coexistent comorbidities as a reason for dyspnea have to be excluded.

Exercise reduces airway sodium ion reabsorption in cystic fibrosis but not in exercise asthma

When ventilating large volumes of air during exercise, airway fluid secretion is essential for airway function. Since these are impaired in cystic fibrosis and exercise-induced asthma, it was the aim of this study to determine how exercise affects airway Na(+) and Cl(-) transport and whether changes depend on exercise intensity. Nasal potential was measured in Ringer's solution, with amiloride to block Na(+) transport, and in low chloride-containing isoproterenol to assess Cl(-) channels. Nasal potential was measured at rest and during submaximal and maximal bicycle ergometer exercise in individuals with cystic fibrosis, exercise-induced asthma and controls. At rest, nasal potential was significantly higher in cystic fibroses than in the others. Maximal exercise decreased nasal potentials in cystic fibrosis and controls but not in exercise asthma. Submaximal exercise decreased nasal potentials only in cystic fibrosis. Cl(-) transport was not affected. Our results indicate that nasal potentials and Na(+) transport were decreased by maximal exercise in healthy and cystic fibrosis, whereas submaximal exercise decreased potentials in cystic fibrosis only. Exercise did not affect nasal potentials in asthmatics. Decreased reabsorption during exercise might favour airway fluid secretion during hyperpnoea. This protective effect appears blunted in patients with exercise-induced asthma.

[Relapsing solitary pulmonary nodule in a patient with ulcerative colitis]

ANAMNESIS AND CLINICAL FINDINGS

A 46-year-old patient with ulcerative colitis, known since she was 27 years old, was found to have a mesenteric granulomatous necrotizing inflammation containing acid-fast bacilli ten years ago. Treatment against tuberculosis was initiated. The ulcerative colitis was treated with mesalazin and, in times of peak activity, additionally with prednisolon. During periods of chronic activity the patient received azathioprin. Six years ago a solitary pulmonary nodule (coin lesion) was detected radiologically in the inferior lobe of the left lung.

INVESTIGATIONS

Laboratory investigations revealed mild inflammation (CRP 1.5 mg/dl). Computed tomography showed a solitary nodule in the left lower pulmonary lobe (diameter 27 mm). Fungi, actinomyces and mycobacteria were not found.

TREATMENT AND COURSE

The pulmonary nodule was resected. During the following years several relapses occurred. After the second relapse lobectomy was performed revealing mycobacterial DNA (not further identified). Treatment against non-tuberculous mycobacteria with clarithromycin, rifampicin and ethambutol was started for 12 months. A third relapse in the form of another solitary pulmonary node occurred one year later. But this nodule regressed spontaneously in part without any additional therapy.

CONCLUSION

In this case the spontaneous regression after the third relapse may represent better control of the ulcerative colitis. An infection seems less likely retrospectively.

[Intermittent positive pressure ventilation in post tuberculosis syndrome]

Pulmonary tuberculosis sequelae with chronic respiratory failure is a clinical picture that is often mentioned, but seldom separately described, in connection with noninvasive ventilation in the case of acute or chronic respiratory failure. We report on the functional data and the ventilation of 26 patients. The patient group is characterized by great chronological latency between the start of pulmonary tuberculosis and the development of respiratory illness. Acute or chronic respiratory failure with this clinical entity should be treated in the form of noninvasive positive pressure ventilation.

[Ventilatory failure in COPD: follow-up under intermittent positive pressure ventilation (IPPV)]

Effectiveness of IPPV in COPD is controversial. We examine the course of 29 patients with longterm IPPV (19 male, 10 female, age 60.3 years, BMI 23.7, FEV1 mean 22% predicted, PaCO2 mean 67 mmHg). PaCO2 is significantly by IPPV reduced. Patients are followed for 2 to 48 months (mean 16.5). Five stop IPPV (1 bilateral lung transplantation, 1 lung volume reduction surgery, 3 non-compliance), 8 die of respiratory failure, 5 of non-respiratory causes (non-RI) (3 tumor, 2 cardiovascular), and 10 survive (SV, 20.5 months). No difference in survival is observed between non-RI and SV. Weight increase by +5% is seen in SV more frequently, lung function is worse in RI, especially in weaning pts., hospital days are less frequent in SV and non-RI. Probability of survival is 70% at 1 year, 57% at 2 years, and 23% at 3 years, and is seriously influenced by non-RI. Our results are influenced by the high number of non-RI, the quitting of IPPV, and the primary inclusion of tumour pts. Still a high number of deaths by RI leads us to the conclusion that IPPV may be helpful for palliation, bridging before surgery and in subgroups who still have to be defined.

[Pharmacological stress echocardiography--a new non-invasive follow-up examination of intermittent ventilation]

BACKGROUND

Patients with chronic respiratory insufficiency frequently develop pulmonary hypertension. Non-invasive intermittent ventilation is usually very successful in these patients to improve blood gas exchange and clinical symptoms. Alterations of pulmonary hemodynamics during non-invasive intermittent ventilation are rarely described. Pharmacological stress echocardiography of the right heart is a new method to examine pulmonary hemodynamics. Aim of this study was to answer the question whether non-invasive intermittent ventilation improves pulmonary hemodynamics.

PATIENTS AND METHOD

Five patients are examined prior to and during non-invasive intermittent ventilation by right ventricular stress echocardiography at rest and during exercise. Pulmonary arterial pressure was registered and compared. The effectiveness of intermittent ventilation was evaluated with respect to blood gas analytic values.

RESULTS

During non-invasive intermittent ventilation all 5 patients improved their pulmonary arterial mean (PAP mean) and systolic pressure, but no statistical significant changes could be observed during the 4.5-months follow-up.

CONCLUSION

Non-invasive intermittent ventilation improves the pulmonary hemodynamics at rest and during exercise the results not being significant.

[The role of non-invasive positive pressure ventilation in lung volume reduction surgery of pulmonary emphysema--a survey of German hospitals]

BACKGROUND

Since the first publication by Cooper et. al. in 1994 of lung volume reduction surgery (LVRS) of emphysema a marked respiratory failure with hyperkapnia (PaCO2 > 55 Torr) has been regarded as an exclusion criterion for LVRS.

PATIENTS AND METHOD

In a survey in German hospitals the question was asked whether non-invasive nasal ventilation (NIPPV) has a role in the management of LVRS. Of 12 hospitals 6 had experience with NIPPV and LVRS in a total of 19 patients with a mean FEV1 of 0.64 +/- 0.101.

RESULTS

LVRS improved FEV1 by 0.20 +/- 0.181. Preoperative NIPPV was short (< 6 months) in 8 patients and resulted in improvement of physical condition and getting the patient used to NIPPV for better perioperative management. In 5 cases NIPPV was used on a long-term basis in order to allow the patient to be included in the LVRS program. In fact 7 of these 13 patients needed ventilation perioperatively, and 4 had to continue long-term NIPPV after surgery. In further 3 patients NIPPV was applied only perioperatively. One patient had to resume NIPPV after 15 months. Two patients started NIPPV 1 resp. 12 months after surgery. Two patients had bronchial cancer which was resected. Four patients died: 1 perioperatively after intubation, 2 after 3 resp. 13 months due to respiratory failure, 1 for cancer relapse after 20 months.

CONCLUSION

NIPPV may be helpful in the planning and management of LVRS in patients with ventilatory failure with hypercarbia.

[Follow-up of intermittent self-ventilation (ISB). Mortality and causes]

BACKGROUND

Intermittent positive pressure ventilation (IPPV) has an impact on morbidity and survival in patients with chronic respiratory failure. We analyse the causes of death in relation to the disease, the age, the effectiveness of and the compliance with IPPV.

PATIENTS

The course of 108 patients, who were on IPPV for a mean of 24 (SD +/- 21) months, is analysed.

RESULTS

Twenty-seven patients die (7/7 AIS, 2/17 muscular dystrophy, 8/45 kyphoskoliosis and TB sequelae, 2/7 other neurological diseases, 6/16 COPD bronchiectasis, 1/1 fibrosis of the lang). The cause of death is in 21 hypoventilation or respiratory infection due to progressive disease (9 patients), air leakage after occlusion of tracheostoma (2 patients), bronchitis (6 patients), discontinuation of IPPV (3 patients). Two patients develop pulmonary failure (atypical mycobacteriosis and asbestosis, pulmonary embolism). Non-pulmonary causes of death are present in 2 (rupture of aortic aneurysm, pleural carcinosis).

CONCLUSIONS

A safe interface for IPPV is needed for longer survival. An efficient system of home-care has to be developed.

[Quality of life and long-term survival with intermittent self-ventilation in respiratory insufficiency caused by thoracic restrictive diseases]

BACKGROUND

Mortality and quality of life are to be assessed in patients with respiratory failure due to restrictive chest wall disease. Neither specific questionnaires, nor perspective studies are available.

PATIENTS AND METHOD

In a retrospective analysis records of mortality and morbidity, physical and social activity, and duration of IPPV are reviewed.

RESULTS

The group consists of 35 patients (mean age 56 +/- 12 years; 22 female, 13 male; 11 post tuberculosis, 24 kyphoskoliosis; IPPV duration 28.5 +/- 20.7 months). Five patients died, 3 of which during the first 4 months: In 3 death is related to respiratory symptoms, 1 is due to pulmonary embolism, 1 to disruption of aortic aneurysm. Hospitalisation is required by 12 patients in 20 instances with a mean duration of 14.2 days. Respiratory symptoms are the cause in 13 instances, special difficulties are met with occlusion of tracheostoma in 3 patients. Professional activity is performed by 14 of the 21 patients < 60 years old. Physical activity is severely reduced in 4 patients, while it is mildly to moderately compromised in 26. Seven of all patients need supplemental oxygen.

CONCLUSION

In respiratory failure due to restrictive chest wall disease treatment with IPPV seems to improve long-term survival and to enhance quality of life.

[Intermittent self-ventilation in neuromuscular diseases. Comparison of lung function parameters in ventilated and non-ventilated patients]

BACKGROUND

Based on neuromuscular-disease patients in our case, we investigate the possibility of elaborating criteria by which to judge when home intermittent mechanical ventilation should be commenced and to access its consequences over an extended period.

PATIENTS AND METHODS

Out of 24 patients with neuromuscular diseases (6 female, 18 male, mean age 32 years), 14 were treated with IPPV. They were suffering from hypercapnic respiratory failure with heavy sleep disruption and corresponding daily symptoms.

RESULTS

The aim was to calculate significant examination parameters to facilitate indication for IPPV. The clinical situation of patients dependent on respiratory support improved under IPPV. We witnessed a "ventilation-saving effect" and--despite progression of the basic disease within the monitoring period--no deterioration of the blood-gas situation.

CONCLUSIONS

It is possible to elaborate criteria for the indication of IPPV based on our group of neuromuscular-disease patients.

[Noninvasive self-ventilation--successful transition aid in the waiting period before lung transplantation?]

BACKGROUND

Non-invasive mechanical ventilation is used with success for ventilatory failure due to derangements of the respiratory pump. Efficacy in pulmonary diseases is controversial. Still non-invasive intermittent ventilation is reported as a mean of bridging the period till lung transplantation can be performed.

PATIENTS AND METHODS

We report of 20 patients from 5 centers who were treated with non-invasive intermittent ventilation while lung transplantation was planned.

RESULTS AND CONCLUSION

Non-invasive intermittent ventilation was seen as successful in 14 patients. Of these 4 are transplanted after up to 2 years, 4 are still waiting, 2 have not yet entered a lung transplantation program, 1 continued non-invasive intermittent ventilation after refusal to be enlisted, 3 meanwhile died. In the group of non-successful non-invasive intermittent ventilation 2 patients were transplanted after a short waiting period. All remaining 4 patients died. It seems that non-invasive intermittent ventilation may be helpful in prolonging the period of survival while waiting for lung transplantation.

[Diaphragmatic paralysis and respiratory insufficiency]

BACKGROUND

Phrenic nerve palsy leads to disfunction of the main respiratory muscle. With bilateral palsy dyspnoea in the supine body position will typically occur. With one-sided lesion symptoms will only appear when a second pulmonary disease is present.

PATIENTS

We refer of 6 patients with bilateral and 5 with unilateral diaphragmatic paresis. In 3 patients neuralgic shoulder-arm-amyotrophy was diagnosed, in further 4 there was suspicion of it. Amyotrophic lateral sclerosis developed in 2 after 4 respectively 8 months. In 1 case a cervical operation led to palsy, mediastinitis in 1 case. Lung function tests showed a restrictive pattern, especially in bilateral palsy.

RESULTS

Vital capacity was reduced by almost 50% respectively 25% in the supine body position. Mouth occlusion pressure reduction was apparent. Near normal to marked hyperkapnia developed in bilateral paresis. In 5 cases non-invasive intermittent ventilation is instituted (2 volume controlled, 3 pressure supported). Two patients died (1 patient with amyotrophic lateral sclerosis after 13 months, 1 with malignant pleurisy after 4 months). Three patients continued non-invasive intermittent ventilation since 14 to 64 months.

[Adult Leigh syndrome. A rare differential diagnosis of central respiratory insufficiency]

Subacute necrotizing encephalomyelopathy (Leigh's syndrome) is a rare neurodegenerative disease in the adult. The precise metabolic defect is unknown, but abnormalities of a mitochondrial enzyme system related to cytochrome-c oxidase or pyruvate dehydrogenase are described. The clinical picture usually consists of an altered breathing pattern, oculomotor paralysis, other signs of cranial nerve dysfunction, ataxia, myoclonic jerks, nystagmus, generalized seizures, optic atrophy and demyelinating peripheral neuropathy. Hypopnea leads to CO2-retention with consecutive loss of consciousness demanding mechanical ventilation. Respiratory failure is the most frequent cause of death. Here we describe two patients with adult onset Leigh's syndrome and we discuss the longterm treatment strategies including vitamin B1 and CPAP mask.

Necrotizing bronchitis, angiitis, and amyloidosis associated with chronic Q fever

The authors report the clinical, radiological and histological findings in a 63-year-old male patient who developed severe necrotizing bronchitis, necrotizing angiitis, and secondary amyloidosis of the right upper love and intermediate bronchus. The patient expired due to respiratory insufficiency. At the age of 27 years, the patient had had radiotherapy of the mediastinum because of suspected Hodgkin's disease. Acute pneumonia suggestive of Q-fever infection was diagnosed at the age of 48. Progressive restrictive lung disease developed during the last decade. Serological evaluation revealed IgM and IgA high titers against Coxiella burnetii. IgA, complement and amyloid deposits were detected in the walls of small arteries. Bronchial lavage and pleural effusions displayed numerous activated T lymphocytes. Analysis of endogenous lectins revealed alterations of the pulmonary defense system. The clinical history, histological and immunological findings suggest that chronic Q fever may induce remarkable changes in the immune system, comparable to autoimmune-reactive diseases.

[Diagnosis, therapy and prognosis of atypical mycobacterial infections--results of a retrospective study]

The most important mycobacteria causing disease in humans are Mycobacterium tuberculosis and Mycobacterium leprae. These germs contrast the so-called atypical mycobacteria. The importance of the atypical mycobacteria was recognized in the fifties. Even if the quantity of atypical mycobacterial disease has increased during the last decades in Germany, it is still a rare disease today, but it is seen in patients with acquired immunodeficiency syndrome more often nowadays. In the period from 1st January 1986 til 31st December 1992 31 HIV-negative patients with a diagnosis of atypical mycobacterial disease have been seen in the department for lung diseases in the Thoraxklinik Heidelberg-Rohrbach. During the same period an atypical mycobacterial disease was diagnosed in 12 out of 413 HIV-positive patients (2.9%) of the AIDS-ambulance of the skin hospital of the University of Heidelberg. Most of the HIV-negative patients showed additional diseases which reduce the immunological resistance. In HIV-positive patients an atypical mycobacteriosis heralds a severe immunodeficiency. Because it is a rare disease and an exact diagnosis is difficult to establish there is a lack of controlled clinical trials and therefore detailed therapeutical guidelines do not exist. A therapeutical approach is also complicated by a lack of effective drugs. With disseminated disease in AIDS-patients, which is mostly caused by Mycobacterium avium-intracellulare, the therapy should be stopped, if there are any severe side-effects. The present results of therapy are still disappointing. In the future the management of atypical mycobacterial disease will be more important, because there is an increasing number of patients with acquired immunodeficiency.

Elastinolytic activity of alveolar macrophages in smoking-associated pulmonary emphysema

Current concepts of pathomechanisms leading to acquired emphysema suggest that alveolar macrophages (AM) activated by cigarette smoking may cause an elastase/antielastase imbalance localized to the microenvironment formed by phagocytes and lung tissue. A functional cell assay was used to evaluate the cell-associated elastinolytic activity of AM. AM were obtained by bronchoalveolar lavage from patients with emphysema and from patients with non obstructive chronic pulmonary diseases (non-COPD) and cultured under serum-free conditions in direct contact with 3H-labeled elastin particles. Elastinolytic activity was calculated from the released radioactivity in culture supernatants and expressed as micrograms of 3H-elastin degraded x 10(-5) AM x 72 h-1. AM of patients with emphysema had significantly higher elastinolytic activity compared to that of non-COPD patients (median: 10.8 versus 4.1 micrograms; P < 0.01). Further differentiation of patients revealed the lowest median activity in sarcoidosis (2.3 micrograms). In respect to smoking habits there was a major difference between smokers with emphysema degraded more than twice the amount of elastin than smokers in the non-COPD group (median:11 versus 3.9 micrograms, P = 0.01). From these data we conclude that AM-derived elsatinolytic proteases may be involved in the destruction of lung elastin, which is thought to be the key event occurring in the pathogenesis of pulmonary emphysema.

Sera from patients with tuberculosis recognize the M2a-epitope (E2-subunit of pyruvate dehydrogenase) specific for primary biliary cirrhosis

Anti-M2 antibodies in primary biliary cirrhosis (PBC) have been shown to react with the alpha-ketoacid dehydrogenase complex of the inner mitochondrial membrane consisting of six epitopes (E2 subunit of the pyruvate dehydrogenase complex (PDC), 70 kD; protein X of the PDC, 56 kD; alpha-ketoglutarate dehydrogenase complex, 52 kD; branched-chain alpha-ketoacid dehydrogenase, 52 kD; E1 alpha subunit of PDC, 45 kD; and E1 beta-subunit of PDC, 36 kD). These epitopes are also present in the M2 fraction which is a chloroform extract from beef heart mitochondria. The E2 subunit of the PDC at 70 kD (M2a), especially, is a major target epitope which is recognized by about 85% of all PBC sera. However, analysing sera from 28 patients with active pulmonary tuberculosis it became evident that 12 (43%) also recognized the PDC-E2 subunit (M2a), as shown by Western blotting using the M2 fraction, the purified PDC, and the recombinant PDC-E2. In contrast, only two of 82 patients with other bacterial and viral infections including 25 patients with Escherichia coli infections reacted with the PBC-specific epitope at 70 kD. Naturally occurring mitochondrial antibodies (NOMA) were present in 54% of the patients with tuberculosis and in 50% of patients with other infectious disorders. They recognized either a determinant at 65 kD (epsilon) or at 60/55 kD (zeta/eta). None of the sera from 100 blood donors had anti-M2 but 14 had NOMA. Testing anti-M2 and NOMA-positive marker sera by Western blotting against membrane fractions derived from mycobacteria and E. coli it could be shown that--like mammalian mitochondria--they contain both the PBC-specific M2 antigen as well as the non-PBC-specific naturally occurring mitochondrial antigen system (NOMAg). The observation that PBC-specific antibodies were preferentially induced in patients suffering from a mycobacterial infection may provide some new clues to the still unknown etiology of PBC.

[Q fever endemic in the Palatinate]

In 1989 investigations revealed a small scale outbreak of Q fever in the area of Vorderpfalz several kilometers west of the city of Ludwigshafen/Rhein. In 16 cases the diagnosis of Q fever has been serologically confirmed by complement fixation test (CF), the estimated number of unknown cases, however, may be considerable. A flock of sheep was determined as the source of infection. Due to the prevalence of the tick species Dermacentor marginatus, one of the main vectors of the infection, the area is considered one of the natural foci of Q fever. Epidemiological aspects as well as case reports are shown.

[The echocardiographic demonstration of a right atrial thrombus and its embolization into the lung]

A 43-year-old man was hospitalized because of extensive bilateral pulmonary tuberculosis. After several weeks of tuberculostatic treatment--at first applied orally, then because of nausea and vomiting parenterally via a central venous catheter--he acutely developed nocturnal dyspnoea and symptoms of shock requiring artificial ventilation. Echocardiography demonstrated dilatation of the right ventricle and a large floating thrombus in the right atrium. During the examination complete displacement of the worm-like thrombus into the pulmonary artery was observed echocardiographically. Despite anticoagulation and immediate operation the patient died 2 days later of protracted shock. The thrombus was found to have been formed in the superior vena cava after placement of the central venous catheter.