Absence of a Crystal Direction Regime in which Sputtering Corresponds to Amorphous Material.

Erosion of material by energetic ions, i.e., sputtering, is widely used in industry and research. Using experiments and simulations that, independently of each other, obtain the sputter yield of thousands of individual grains, we demonstrate here that the sputter yield for heavy keV ions on metals changes as a continuous function of the crystal direction. Moreover, we show that polycrystalline metals with randomly oriented grains do not sputter with the same yield as the amorphous material. The key reason for this is attributed to linear collision sequences rather than channeling.

Complexity of PEComas : Diagnostic approach, molecular background, clinical management.

Perivascular epithelioid cell neoplasms (PEComas) are a family of mesenchymal neoplasms with features of both melanotic and smooth muscle differentiation. PEComa morphology is highly variable and encompasses epithelioid to spindle cells often with clear cytoplasm and prominent nucleoli. Molecularly, most PEComas are defined by a loss of function of the TSC1/TSC2 complex. Additionally, a distinct small subset of PEComas harboring rearrangements of the TFE3 (Xp11) gene locus has been identified. By presenting a series of three case reports with distinct features, we demonstrate diagnostic pitfalls as well as the importance of molecular work-up of PEComas because of important therapeutic consequences.

[Complexity of PEComas : Diagnostic approach, molecular background, clinical management (German version)]. / Komplexität von PEComen : Diagnose, Molekulargenetik, klinisches Management.

Perivascular epithelioid cell neoplasms (PEComas) are a family of mesenchymal neoplasms with features of both melanotic and smooth muscle differentiation. PEComa morphology is highly variable and encompasses epithelioid to spindle cells often with clear cytoplasm and prominent nucleoli. Molecularly, most PEComas are defined by a loss of function of the TSC1/TSC2 complex. Additionally, a distinct small subset of PEComas harboring rearrangements of the TFE3 (Xp11) gene locus has been identified. By presenting a series of three case reports with distinct features, we demonstrate diagnostic pitfalls as well as the importance of molecular work-up of PEComas because of important therapeutic consequences.

[Influence of primary lymph node status of colorectal cancer on the development of pulmonary metastases and thoracic lymph node metastases]. / Einfluss des primären Lymphknotenstatus kolorektaler Karzinome auf die Entwicklung von Lungenmetastasen und thorakalen Lymphknotenmetastasen.

BACKGROUND: The lungs are the second most common organ site for metastases in patients with colorectal cancer (CRC). Lymph node metastasis of CRC represents a prognostic factor for survival. OBJECTIVE: The present study investigated the influence of CRC lymph node metastasis on lung metastasis, in particular thoracic lymph node metastasis. MATERIAL AND METHODS: A retrospective analysis of 88 patients (n = 56 male) with curative resection of lung metastases of CRC was performed. Primary endpoint: influence of lymph node status of CRC on lung metastases. Secondary endpoints: disease-free survival and overall survival. Statistical evaluation was carried out with SPSS. RESULTS: In 48 patients a positive lymph node status of CRC and in 9 patients an N+ status of lung metastases were determined. The lymph node status of the CRC significantly affected the incidence of synchronous metastases (p = 0.03), disease-free interval until formation of metachronous lung metastases (p = 0.012) and the overall survival of patients with CRC (p = 0.048). The 5­year survival rate for CRC patients with lung metastases was 48.7% after pulmonary metastasectomy. Thoracic lymph node involvement also significantly affected survival (p = 0.001). CONCLUSION: Screening for pulmonary metastases should be included in the staging and follow-up of all patients with CRC, especially in patients with a positive lymph node status of the CRC.

SIESTA: A high current ion source for erosion and retention studies.

Second ion experiment for sputtering and TDS analysis is a high-current ion source for erosion and retention studies with focus on wall materials for fusion devices. The system is composed of a DuoPIGatron type ion source, three consecutive grids for ion extraction, acceleration and beam focusing, a differential pumping stage, a dipole magnet for mass filtering, a quadrupole doublet lens, a target chamber, a load-lock, and a chamber for thermal desorption spectrometry. The acceleration potential of the source can be varied between 500 V and 10 kV. The target chamber has a base pressure of 10-8 mbar and an operating pressure of 5 × 10-7 mbar. The target can be rotated to study angle-dependent effects and can be heated via electron-impact heating up to 1300 K for high temperature erosion and implantation studies. The target chamber is equipped with an in situ magnetic suspension balance. The operating parameters of the ion source were mapped to achieve the maximum ion current at the target for various gas species and accelerating potentials. The beam emittance for a D3 + ion beam was measured after deflection in the dipole magnet. This was used for ion beam simulations, which were instrumental for the design of the quadrupole lenses. If the quadrupole doublet is used, the ion flux to the target is increased by up to a factor of 4. Additionally, the relative population of neutral particles present in the beam at the target was quantified and is equal to 0.8% when averaged over the measurement positions. The typical beam footprint at the target under normal incidence has an area of 0.5 cm2. The ion current reaching the target increases with the accelerating potential. Due to this effect, the ion flux density at the target in the low-ion-impact-energy range can be increased by operating the source at a higher extraction potential and by applying a (decelerating) potential to the target. Ion impact energies as low as 200 eV/D are achieved this way with a D3 + current of 100 µA when focusing the beam with the quadrupole doublet lens, equating to a D particle flux density of 3.7 × 1019 m-2 s-1. At ion impact energies of 2 keV/D, the maximum achievable flux density with D3 + is 6 × 1019 D m-2 s-1. Experimental determination of sputter yields was performed via ex situ weight loss measurement for bulk Au samples, showing reasonably good agreement with simulations and experimental data from the literature.

Spring-driven high speed valve for massive gas injection in tokamaks.

A new high speed gas valve was developed for disruption mitigation studies in the tokamak ASDEX Upgrade. The valve was designed to operate inside the vacuum vessel to reduce the time of flight of the injected gas and to prevent dispersion of the gas cloud before the gas reaches the plasma. A spring-driven mechanism was chosen for the valve as it is robust against the high magnetic fields and electromagnetic disturbances inside the vessel. The internal gas reservoir (128 cm3) of the valve, which holds the mitigation gas, is opened within 1.5 ms, and the maximal stroke between the valve plate and nozzle (diameter 13 mm) is 4.5 mm. This allows a peak flow rate of 72 kPam3/s after 1 ms which was determined both analytically and numerically. The highest gas velocity (approximately 560 m/s) is reached 0.6 ms after the valve is opened. The gas cloud expands in a pear shape with an opening angle of 49°.

[A Screening-Tool for Three Dimensions of Work-Related Behavior and Experience Patterns in the Psychosomatic Rehabilitation - A Proposal for a Short-Form of the Occupational Stress and Coping Inventory (AVEM-3D)]. / Ein Verfahren zum Screening dreier Dimensionen arbeitsbezogener Verhaltens- und Erlebensmuster in der psychosomatischen Rehabilitation ­ Vorschlag für eine Kurzform AVEM-3D.

Objectives: The assessment of work pressures is of particular importance in psychosomatic rehabilitation. An established questionnaire is the Occupational Stress and Coping Inventory (German abbr. AVEM), but it is quite long and with regard to scoring time-consuming in routine clinical care. It should therefore be tested, whether a shortened version of the AVEM can be developed, which is able to assess the formerly described three second-order factors of the AVEM, namely Working Commitment, Resilience, and Emotions, sufficiently reliable and valid, and which also may be used for screening of patients with prominent work-related behavior and experience patterns. Methods: Data were collected at admission from consecutive samples of three hospitals of psychosomatic rehabilitation (N = 10,635 patients). The sample was randomly divided in two subsamples (design and validation sample). Using exploratory principal component analyses in the design sample, items with the highest factor loadings for the three new scales were selected and evaluated psychometrically using the validation sample. Possible Cut-off values ought to be derived from distribution patterns of scores in the scales. Relationships with sociodemographic, occupational and diagnosis-related characteristics, as well as with patterns of work-related experiences and behaviors are examined. Results: The three performed principal component analyses explained in the design sample on the respective first factor between 31 % and 34 % of the variance. The selected 20 items were assigned to the 3-factor structure in the validation sample as expected. The three new scales are sufficiently reliable with values of Cronbach's α between 0,84 and 0,88. The naming of the three new scales is based on the names of the secondary factors. Cut-off values for the identification of distinctive patient-reported data are proposed. Conclusion: Main advantages of the proposed shortened version AVEM-3D are that with a considerable smaller number of items the three main dimensions of relevant work-related behavior and experience patterns can be reliably measured. The proposed measure is simple and economic to use and interpret. Based on the present sample we provide means and standard deviations as reference at admission of psychosomatic rehabilitation. As a limitation it should be mentioned that further evaluation of reliability, validity and sensitivity to change restricted to the items of the shortened version is necessary. The practicability and validity of the proposed cut-off values cannot yet be conclusively assessed. Finally, the validity of the AVEM-3D in groups of indications other than psychosomatic patients and in healthy persons remains to be examined.

[Surgical reconstructive procedures of the chest wall after mediastinitis]. / Plastische Rekonstruktionsverfahren der Brustwand nach Mediastinitis.

Sternal osteomyelitis as a direct consequence of advanced mediastinitis or as in most cases after median sternotomy is still associated with a prolonged hospital stay, increased morbidity and postoperative mortality. Early diagnosis and an adequate surgical treatment are decisive for the prognosis. Prerequisites for a secondary stabilization of the chest wall using wires or plates are sterile wound conditions. Diverse reconstructive techniques are available for anterior chest wall reconstruction depending on the defect size and localization. The various reconstructive methods including local and free flap coverage are described in this review article.

A compact lithium pellet injector for tokamak pedestal studies in ASDEX Upgrade.

Experiments have been performed at ASDEX Upgrade, aiming to investigate the impact of lithium in an all-metal-wall tokamak and attempting to enhance the pedestal operational space. For this purpose, a lithium pellet injector has been developed, capable of injecting pellets carrying a particle content ranging from 1.82 × 10(19) atoms (0.21 mg) to 1.64 × 10(20) atoms (1.89 mg). The maximum repetition rate is about 2 Hz. Free flight launch from the torus outboard side without a guiding tube was realized. In such a configuration, angular dispersion and speed scatter are low, and a transfer efficiency exceeding 90% was achieved in the test bed. Pellets are accelerated in a gas gun; hence special care was taken to avoid deleterious effects by the propellant gas pulse. Therefore, the main plasma gas species was applied as propellant gas, leading to speeds ranging from 420 m/s to 700 m/s. In order to minimize the residual amount of gas to be introduced into the plasma vessel, a large expansion volume equipped with a cryopump was added into the flight path. In view of the experiments, an optimal propellant gas pressure of 50 bars was chosen for operation, since at this pressure maximum efficiency and low propellant gas flux coincide. This led to pellet speeds of 585 m/s ± 32 m/s. Lithium injection has been achieved at ASDEX Upgrade, showing deep pellet penetration into the plasma, though pedestal broadening has not been observed yet.

[Outcomes of Stage-Adapted Surgical Treatment of Pleural Empyema]. / Ergebnisse der stadienadaptierten chirurgischen Therapie von Pleuraempyemen.

BACKGROUND: The surgical treatment of pleural empyema should be carried out depending on the stage of the disease and the patient's symptoms. The aim of this study was to evaluate the outcomes of surgical pleural empyema treatment. PATIENTS AND METHODS: Retrospective analysis of all patients with pleural empyema treated surgically between January 2008 and December 2013. The primary endpoint of the study was inpatient lethality. Secondary endpoints included duration of inpatient stay, type of treatment (surgical/conservative), proof of pathogen and type, alteration and duration of antibiotic therapy. RESULTS: Of 359 patients, 0.8 % (n = 3) had stage I empyema, 50.4 % (n = 181) had stage II and 48.7 % (n = 175) had stage III. The most frequent causes (32.4 %) included acute pneumonia (parapneumonic pleural empyema), surgery (usually thoracic) in 18.0 % of cases and previous pneumonia (postpneumonic pleural empyema) in 15.4 %. Surgery was performed in 86 % of cases (operative procedures: open thoracotomy 85 %, VATS 15 %). The average duration of inpatient stay was 20 days for stages II and III. Recovery following VATS was significantly shorter in stage II compared to thoracotomy (p = 0.022). Hospital lethality amounted to 7.0 % (25 patients). The lethality rate was 5.5 % (10/185) in stage II and 8.6 % (15/175) in stage III. Patients with confirmed pathogens had a significantly worse mortality rate across all stages (9.8 %) than patients with no confirmed pathogens (4.0 %, p = 0.034). Age, malignant underlying disease, multiple comorbidities, immunosuppression, a change in antibiotic regimens and sepsis were significant risk factors. CONCLUSION: The inpatient lethality of patients with pleural empyema correlates with the stage of the condition. Positive confirmation of pathogens, sepsis, a higher age, multiple comorbidities, malignant tumour disease, immunosuppression and a change of antibiotics are negative prognostic factors.

[Persistent pleural effusion following thoracic surgery]. / Persistierender Erguss nach thoraxchirurgischen Eingriffen.

BACKGROUND: Persistent postoperative pleural effusion can occur after thoracic surgery and might lead to progressive dyspnea with a subsequent complicated and prolonged hospital stay. OBJECTIVES: The etiology, prevention and therapy of persistent pleural effusion after thoracic surgical interventions are presented. MATERIAL AND METHODS: A selective literature search was carried out in Medline (pleural effusion, pleural empyema and chylothorax). RESULTS: Persistent pleural effusions were observed especially after lung resection due to disorders in the pleural fluid balance and reduced postoperative lung expansion. An adequate chest tube management and postoperative physical therapy can reduce the incidence of postoperative pleural effusion. Relevant postoperative bleeding causes a hemothorax. An infection of the pleural effusion is defined as pleural empyema. These patients suffer from a significantly higher postoperative morbidity and require an adjusted multimodal treatment. Intraoperative injury of the thoracic duct can result in a postoperative chylothorax, which should be diagnosed early with specific laboratory investigations of the milky fluid. Interventional radiological procedures have now taken their place alongside conservative measures and surgical procedures in the therapy of chylothorax. CONCLUSION: Persistent postoperative pleural effusion after thoracic surgical interventions warrant early diagnosis and an adjusted treatment in order to avoid further complications and to shorten the postoperative hospital stay.

[Radical pleurectomy and hyperthermic intrathoracic chemotherapy for treatment of thymoma with pleural spread]. / Radikale Pleurektomie und hypertherme intrathorakale Chemotherapie zur Behandlung pleural metastasierter Thymome.

INTRODUCTION: Patients with pleural thymoma spread (Masaoka stage IV a) should be treated within a multimodal treatment regime. However, the extent of local surgical resection to achieve optimal tumour control remains controversial. PATIENTS AND METHODS: Prospective analysis between September 2008 and April 2013 of all patients with a Masaoka stage IV a thymoma, who underwent radical pleurectomy/decortication (P/D) followed by hyperthermic intrathoracic chemotherapy (HITHOC). RESULTS: A total of 11 patients (male n = 7; mean age 46.5 ± 11.4 years) with a primary stage IV a thymoma (n = 3) or thymoma with pleural relapse (n = 8) were included after successful transsternal thymoma resection. WHO histological classification was: B1 n = 1, B2 n = 6, B3 n = 3 and C n = 1. A radical P/D (5/11; 45 %) was extended with resection of the pericardium and diaphragm in 6/11 (55 %) patients. After surgical resection (91 % complete macroscopic R0/R1-resection) the HITHOC with cisplatin (100 mg/m2 body surface area (BSA) n = 7; 150 mg/m2 BSA n = 4) was performed for one hour at 42 °C. Operative revision was necessary in two patients (chylo- and hematothorax) with one patient also requiring temporary renal replacement therapy due acute renal failure (cisplatin 150 mg/m2 BSA). 30-day mortality was 0 %. Local recurrence (pulmonary n = 1, paravertebral n = 2) was documented in 3/10 (30 %) patients after R0/R1 resection. After a mean follow-up of 23 months the overall median survival was 27 months and 82 % (9/11) patients are still alive at the end of the study period. CONCLUSIONS: Masaoka stage IV a thymoma could be safely treated with lung-sparing radical P/D and HITHOC with cisplatin in a multimodality treatment regime. Early results with respect to recurrence and survival are encouraging, but further studies are warranted and we have to await long-term results.

[Regional treatment of malignant pleural mesothelioma: results from the tumor centre Regensburg]. / Regionale Versorgung des malignen Pleuramesothelioms : Ergebnisse aus dem Tumorzentrum Regensburg.

INTRODUCTION: Malignant pleural mesothelioma (MPM) is an aggressive, malignant tumor of the pleural surface and is strongly associated with asbestos exposure. Incidence of MPM will reach its peak over the coming years. Most patients present with advanced tumor stages and therefore surgical options are limited. PATIENTS AND METHODS: Retrospective analysis of all patients with MPM reported to the tumor centre Regensburg between January 1998 and August 2011. RESULTS: A total of 118 patients (85 % male) with cytologically or histologically confirmed MPM were reported. The mean age at diagnosis was 67 years (range 45-84 years) and 65 % of patients had a history of asbestos exposure. The incidence of MPM at the tumor centre Regensburg was 0.8/100,000 inhabitants with obvious regional differences depending on asbestos exposure. Staging was completed in 81 patients (67 %): stage I 9 %, stage II 22 %, stage III 23 % and stage IV 46 %. Of the patients 87 (74 %) underwent at least one surgical procedure: diagnostic thoracoscopy with biopsy (n = 37, 43 %), debulking surgery or talcum pleurodesis (n = 33, 38 %) and potentially curative resection (n = 17, 19 %). After a mean follow-up of 20 months the overall median survival was 14 months (1 year survival rate 62 %, 3 year survival rate 15 %). Patients had a significantly better median survival of 18 months after curative resection. CONCLUSIONS: The distribution of MPM varies according to regional and industrial asbestos exposure. Screening and diagnostics should concentrate on locations with higher incidence of MPM to facilitate surgical therapy in a multimodal treatment regime.

Local and systemic exposure of cisplatin during hyperthermic intrathoracic chemotherapy perfusion after pleurectomy and decortication for treatment of pleural malignancies.

BACKGROUND: Assessing the pharmacokinetics of intrapleurally administered cisplatin during hyperthermic intrathoracic chemotherapy perfusion (HITHOC) following pleurectomy/decortication in patients with malignant pleural mesothelioma or advanced thymoma with pleural spread. METHODS: Pharmacokinetic analysis (ICP-MS) of intrapleural cisplatin with a dosage of 100 mg/m(2) (n = 5) or 150 mg/m(2) (n = 5) at 42°C perfusate temperature. Simultaneous pleural perfusion fluid and serum samples were collected at the beginning and every 15 min. Serum samples were collected at the end of the operation, 6, 12, and 24 hr postoperative. RESULTS: Mean cisplatin levels in the perfusate slightly decreased during the HITHOC. The mean area under the curve ratios (AUC perfusate :AUC serum ) of cisplatin were nearly similar. The mean AUCs of cisplatin in the perfusate were approximately 58 and 55 times greater than detected in the serum. The mean peak of cisplatin in the serum was reached after 1 hr of HITHOC. The AUC of cisplatin in the serum did not significantly differ (P = 0.18) between both groups up to 24 hr after perfusion. CONCLUSIONS: HITHOC with cisplatin provides a pharmacological advantage of high local intrapleural cisplatin concentrations. Elevation of the cisplatin dosage to 150 mg/m(2) did not lead to a significant increase of the systemic cisplatin concentration.

Surgical resection of thymoma still represents the first choice of treatment.

OBJECTIVE: The aim of this study was to analyze the clinicopathological factors, treatment strategies and survival rates after surgical resection of thymoma. METHODS: Between 12/1997 and 5/2010, 42 patients underwent surgical resection of the thymus. The presence of a thymoma was determined by histological examination in 23 patients, while patients with hyperplasia of the thymus (n = 19) were excluded from further analysis. RESULTS: Myasthenia gravis coexisted in 9/23 (39.1%) patients. Thymomas were classified according to the Masaoka staging system (I: n = 6 [26.1%], IIa: n = 7 [30.4%], IIb: n = 2 [8.7%], III: n = 1 [4.4%], IVa: n = 7 [30.4%]) and the WHO histological classification (A: n = 4 [17.4%], AB: n = 5 [21.7%], B1: n = 1 [4.4%], B2: n = 8 [34.8%], B3: n = 3 [13%], C: n = 2 [8.7%]). Recurrence of thymoma was documented in three (13%) patients. After a mean follow-up of 58.4 months, 21 (91.3%) patients are alive. The overall survival rate was 95% and 87.8%, at 2 and 5 years, respectively. The disease-free interval at 5 years was 85% for the 17 (73.9%) patients with complete resection. CONCLUSIONS: Surgical resection of thymoma is the preferred treatment, because it is safe and effective with a low rate of recurrence and a good long-term survival. Advanced and invasive thymomas require a multimodal approach for better local tumor control and further improvement of prognosis.

The compact neutron spectrometer at ASDEX Upgrade.

The first neutron spectrometer of ASDEX Upgrade (AUG) was installed in November 2008. It is a compact neutron spectrometer (CNS) based on a BC501A liquid scintillating detector, which can simultaneously measure 2.45-MeV and 14-MeV neutrons emitted from deuterium (D) plasmas and γ radiation. The scintillating detector is coupled to a digital pulse shape discrimination data acquisition (DPSD) system capable of count rates up to 10(6) s(-1). The DPSD system can operate in acquisition and processing mode. With the latter n-γ discrimination is performed off-line based on the two-gate method. The paper describes the tests of the CNS and its installation at AUG. The neutron emission from the D plasma measured during a discharge with high auxiliary heating power was used to validate the CNS performance. The study of the optimal settings for the DPSD data processing to maximize the n-γ discrimination capability of the CNS is reported. The CNS measured both 2.45-MeV and 14-MeV neutrons emitted in AUG D plasmas with a maximum count rate of 5.4 × 10(5) s(-1) (>10 times higher than similar spectrometers previously achieved) with an efficiency of 9.3 × 10(-10) events per AUG neutron.

Common trisomy mosaicism diagnosed in amniocytes involving chromosomes 13, 18, 20 and 21: karyotype-phenotype correlations.

Karyotype-phenotype correlations of common trisomy mosaicism prenatally diagnosed via amniocentesis was reviewed in 305 new cases from a collaboration of North American cytogenetic laboratories. Abnormal outcome was noted in 10/25 (40%) cases of 47,+13/46, 17/31 (54%) cases of 47,+18/46, 10/152 (6.5%) cases of 47,+20/46, and in 49/97 (50%) cases of 47,+21/46 mosaicism. Risk of abnormal outcome in pregnancies with less than 50% trisomic cells and greater than 50% trisomic cells were: 26% (4/15) versus 60% (6/10) for 47,+13/46, 52% (11/21) versus 75% (6/8) for 47,+18/46, 4.5% (6/132) versus 20% (4/20) 47,+20/46, and 45% (27/60) versus 59% (22/37) for 47,+21/46. Phenotypically normal liveborns were observed with mean trisomic cell lines of 9.3% for 47,+13/46, 8.6% for 47,+18/46, 27% for 47, +20/46, and 17% for 47,+21/46. Cytogenetic confirmation rates were 46% (6/13 cases) for 47,+13/46 mosaicism, 66% (8/12 cases) for 47, +18/46, 10% (10/97 cases) for 47,+20/46, and 44% (24/54 cases) for 47,+21/46. There were higher confirmation rates in pregnancies with abnormal versus normal outcome: 50% versus 44% for 47,+13/46 mosaicism, 100% versus 33% for 47,+18/46, 66% versus 7% for 47, +20/46, and 55% versus 40% for 47,+21/46. Repeat amniocentesis is not helpful in predicting clinical outcome. It may be considered when there is insufficient number of cells or cultures to establish a diagnosis. Fetal blood sampling may have a role in mosaic trisomy 13, 18, and 21 as the risk for abnormal outcome increases with positive confirmation: 1/5 (20%) normal cases versus 5/8 (62%) abnormal cases. High resolution ultrasound examination(s) is recommended for clinical correlation and to facilitate genetic counselling.

Relocation of urf a from the mitochondrion to the nucleus cures the mitochondrial mutator phenotype in the fission yeast Schizosaccharomyces pombe.

In previous papers we have reported the characterisation of mitochondrial mutator mutants of Schizosaccharomzyces pombe. In contrast to nuclear mutator mutants known from other eucaryotes, this mutator phenotype correlates with mutations in an unassigned open reading frame (urf a) in the mitochondrial genome. Since an efficient biolistic transformation system for fission yeast mitochondria is not yet available, we relocated the mitochondrial urf a gene to the nucleus. As host strain for the ectopic expression, we used the nonsense mutant ana(r)-6, which carries a premature stop codon in the urf a gene. The phenotype of this mutant is characterised by continuous segregation of progeny giving rise to fully respiration competent colonies, colonies that show moderate growth on glycerol and a fraction of colonies that are unable to grow on glycerol. The phenotype of this mutant provides an excellent tool with which to study the effects on the mutator phenotype of ectopic expression of the urf a gene. Since a UGA codon encoding tryptophan is present in the original mitochondrial gene, we constructed two types of expression cassettes containing either the mitochondrial version of the urf a gene (mt-urf a) or a standard genetic code version (nc-urf a; UGA replaced by UGG) fused to the N-terminal import leader sequence of the cox4 gene of Saccharomyces cerevisiae. We show that the expression of the mt-urf a gene in its new location is able to cure, at least in part, the phenotype of mutant ana(r)-6, whereas the expression of the nc-urf a gene completely restores the wild-type (non-mutator) phenotype. The significant similarity of the urf a gene to the mitochondrial var1 gene of S. cerevisiae and homologous genes in other yeasts suggests that the urf a gene product might be a ribosomal protein with a dual function in protein synthesis and maintenance of mitochondrial DNA integrity.

Rare trisomy mosaicism diagnosed in amniocytes, involving an autosome other than chromosomes 13, 18, 20, and 21: karyotype/phenotype correlations.

In order to determine the significance of trisomy mosaicism of an autosome other than chromosomes 13, 18, 20, and 21, 151 such cases diagnosed prenatally through amniocentesis were reviewed. These rare trisomy mosaicism cases include 54 from 17 cytogenetic laboratories, 34 from a previous North American mosaicism survey, and 63 from published reports. All were cases of true mosaicism with information available on pregnancy outcome, and with no evidence of biased ascertainment. There were 11 cases of 46/47, +2; 2 of 46/47, +3; 2 of 46/47, +4; 5 of 46/47, +5; 3 of 46/47, +6; 8 of 46/47, +7; 14 of 46/47, +8; 25 of 46/47, +9; 2 of 46/47, +11; 23 of 46/47, +12; 5 of 46/47, +14; 11 of 46/47, +15; 21 of 46/47, +16; 7 of 46/47, +17; 1 of 46/47, +19; and 11 of 46/47, +22. As to the risk of an abnormal outcome, the data showed a very high risk (> 60 per cent) for 46/47, +2, 46/47, +16, and 46/47, +22; a high risk (40-59 per cent) for 46/47, +5, 46/47, +9, 46/47, +14, and 46/47, +15; a moderately high risk (20-39 per cent) for 46/47, +12; a moderate risk (up to 19 per cent) for 46/47, +7 and 46/47, +7 and 46/47, +8; a low risk for 46/47, +17; and an undetermined risk, due to lack of cases, for the remaining autosomal trisomy mosaics. Most cases were evaluated at birth or at termination, so subtle abnormalities may have escaped detection and developmental retardation was not evaluated at all. Comparison of the phenotypes of prenatally diagnosed abnormal cases and postnatally diagnosed cases with the same diagnosis showed considerable concordance. Since the majority of anomalies noted are prenatally detectable with ultrasound, an ultrasound examination should be performed in all prenatally diagnosed cases. In cytogenetic confirmation studies, the data showed much higher confirmation rates in cases with abnormal outcomes than in cases with normal outcomes [81 per cent vs. 55 per cent for fibroblasts (from skin, fetal tissue, and/or cord); 88 per cent vs. 46 per cent for placental cells; 22 per cent vs. 10 per cent for blood cells]. The confirmation rate reached 85 per cent when both fibroblasts and placental tissues were studied in the same case (with trisomic cells found in one or the other, or both). Therefore, one must emphasize that both fibroblasts and placental tissues should be studied. Except for 46/47, +8 and 46/47, +9, PUBS is of limited value for prenatal diagnosis of rate trisomy mosaicism. DNA studies for UPD are suggested for certain chromosomes with established imprinting effects, such as chromosomes 7, 11, 14, and 15, and perhaps for chromosomes 2 and 16, where imprinting effects are likely.