Site-directed mutagenesis of two trans-regulatory genes (tat-III,trs) of HIV-1.

Point mutations were introduced into the overlapping trans-regulatory genes (tat-III and trs) of human immunodeficiency virus type 1 (HIV-1), and the mutants were evaluated for virus expression. The results showed that tat-III has a positive transacting role and is required for transcriptional activation. A chain terminating mutation early in the trs gene resulted in an increase in transcription of viral messenger RNA as measured by nuclear transcription experiments, but only one major species of viral messenger RNA (1.8 kilobases) was detected, and little or no viral structural proteins were made. Thus, the trs gene product is essential for expression of virus structural proteins but, at the same time, may have a negative trans-regulatory role in transcription. Cotransfection of the point mutant proviruses defective in tat or trs with each other or with a complementary DNA clone containing tat and trs sequences restored the normal transcription pattern and subsequent virus production.

Hydrogen sensors and switches from electrodeposited palladium mesowire arrays.

Hydrogen sensors and hydrogen-activated switches were fabricated from arrays of mesoscopic palladium wires. These palladium "mesowire" arrays were prepared by electrodeposition onto graphite surfaces and were transferred onto a cyanoacrylate film. Exposure to hydrogen gas caused a rapid (less than 75 milliseconds) reversible decrease in the resistance of the array that correlated with the hydrogen concentration over a range from 2 to 10%. The sensor response appears to involve the closing of nanoscopic gaps or "break junctions" in wires caused by the dilation of palladium grains undergoing hydrogen absorption. Wire arrays in which all wires possessed nanoscopic gaps reverted to open circuits in the absence of hydrogen gas.

Analysis of a non-ras 21-kDa protein in patients with metastatic testicular germ-cell tumors.

A novel protein of 21 kDa (p21) has been detected in the sera of patients with different solid tumors. The serum levels of this p21 protein were measured in seven patients with metastatic testicular germ-cell tumors before and after chemotherapy using an enzyme-linked immunosorbent assay. In five out of six patients who responded to chemotherapy a concomitant decrease of p21 serum levels was found. The decrease of p21 was in accordance with the decline of the established tumor markers alpha-fetoprotein, human chorionic gonadotropin beta-subunit and lactate dehydrogenase in three patients with non-seminomatous tumors and with the decline of lactate dehydrogenase and the clinical response in two patients with seminoma. In one patient the predicted decline of p21 did not occur despite the patient's clinical response to chemotherapy. In the seventh patient, who relapsed directly after chemotherapy, no decline of either p21 levels or tumor markers was observed. The absolute amount of the p21 protein prior to chemotherapy did not correlate with the patients' tumor burden. Elevated levels of p21 were found in patients with seminomatous and non-seminomatous germ-cell tumors. Since seminoma patients do not secrete tumor markers like alpha-fetoprotein or human chorionic gonadotropin beta, the determination of p21 levels may help to evaluate the efficacy of chemotherapy in patients with seminomatous as well as in patients with marker-negative non-seminomatous germ-cell tumors. The biological role of p21 and its clinical significance will be further investigated.

[Long-term central venous lines and their complications]. / Langfristige zentralvenöse Zugänge und deren Komplikationsmanagement.

The implantation of permanent (> 14 days) central venous catheters is constantly increasing, accelerated by a trend toward outpatient therapies. Subcutaneous tunneled and non-tunneled catheters as well as port systems are available. The interventional radiologist plays an important role in the implantation of central venous catheters as well as in detection and treatment of any complications. Various access ways via peripheral and central veins are described and the implantation techniques for the different systems explained. The use of peel-away sheaths allows the radiologist to implant subcutaneous tunneled catheters via the Seldinger technique without surgical preparation. Procedure-related early and late complications may occur, and the radiologist plays an important role in the surveillance and management of catheter-associated complications. This review demonstrates the different catheter systems and implantation techniques.

[Accuracy of the sonographic determination of the splenic weight in comparison with the weight at autopsy]. / Genauigkeit der sonographischen Milzgewichtsbestimmung am Lebenden im Vergleich zum pathologischen Korrelat.

PURPOSE: The weight of the spleen can be easily calculated from sonographic measurements. This study investigates the correlations between the weight of the spleen determined sonographically and the weight measured at autopsy or after splenectomy. MATERIALS AND METHODS: The splenic weight at autopsy or after splenectomy was correlated with the calculated sonographic splenic weight in 55 patients who had a sonographic examination within the preceding three weeks. RESULTS: A significant correlation (r = 0.978) was found between the sonographically calculated splenic weight (460.82 grams) and the measured weight of the removed spleen (average weight 463.18 grams). Spleens weighing more than 1 kg showed a slightly weaker correlation. CONCLUSION: This study proves that the simple formula of length x transverse diameter x vertical diameter x 0.6 provides a reliable calculation of the weight of the spleen.

[Importance of duplex velocity histograms in the diagnosis of liver cirrhosis]. / Bedeutung des Duplex-Geschwindigkeitshistogramms zur Diagnose der Leberzirrhose.

PURPOSE: A prospective study was carried out to determine the diagnostic value of velocity histograms of hepatic veins in patients with liver cirrhosis and healthy subjects. METHODS: The hepatic veins of ten healthy subjects and ten patients with liver cirrhosis were examined by the Doppler method. The velocity histogram measures the velocity variation at a defined area in the duplex tracing. Within this tracing, the peak, mean, mode and velocity range were measured. RESULTS: A velocity range of 0.02 +/- 0.015 m/s was examined in healthy subjects, and a range of 0.06 +/- 0.013 was examined in liver cirrhosis patients (p < 0.001). The other measurement options showed no significant changes between the healthy subjects and the liver cirrhosis patients (p < 0.05). CONCLUSIONS: Until now, differentiation of the hepatic vein tracings was possible only on a qualitative basis. With the assessment of the velocity range it is possible to obtain a more objective differentiation between the duplex tracing in hepatic veins of liver cirrhosis patients and healthy subjects.

Regulation of the proto-oncogenes c-sis, c-fos, c-myc and c-myb in acute myeloid leukemias.

RNA transcriptional levels of the proto-oncogenes c-sis, c-fos, c-myb and c-myc were measured in peripheral blood leukemic blast cells of 16 patients with acute myeloid leukemia (AML) of different FAB subtypes, 8 being at diagnosis and 8 upon relapse. The studied proto-oncogenes were found to be regulated but varied considerably within morphologically identical subtypes. This is consistent with the clinically observable diverse behavior of seemingly identical AMLs as to the course and outcome of the individual disease. Overexpression of c-sis and c-myc was found more often in AML upon relapse than at diagnosis and in two cases overexpression not found at diagnosis was present at relapse. This implies alterations of biological behavior in the course of antileukemic drug therapy. A decline of c-myb expression was observed in one patient studied throughout therapy which was found to be associated with a complete but transient hematological remission after chemotherapy.

[Niels Stensen--physician, naturalist and priest]. / Niels Stensen--Arzt, Naturforscher und Priester.

Niels Stensen born 1638 not only characterized the ductus paroticus he also made fundamental discoveries in paleontology and crystallography. After converting to catholicism he spend all his creativeness to strengthen the catholic church living in Franciscan humility.

[Splenic injury after colonoscopy: a retrospective study and review of the literature]. / Milzverletzung nach Koloskopie. Eine retrospektive Studie und Analyse der Literatur.

BACKGROUND AND OBJECTIVE: The increasing number of preventive screening investigations in the course of obtaining early diagnosis of colon cancer, has been leading to an increase in the number of colonoscopies in Germany. Splenic injury is one of the complications to be aware of, if postinterventional abdominal symptoms occur. PATIENTS AND METHODS: This retrospective study was based on the answers to questionnaires sent to 220 members of the Working Party of Leading Hospital-Based Gastroenterologists. The response rate was 40%. RESULTS: Thirteen of the gastroenterologists reported a total of 16 splenic injuries, a rate of about one injury per 87,000 (about 0.001 %) this compares to a worldwide published splenic injury rate of 0.004 %. But the actual numbers are probably higher in Germany as well. CONCLUSIONS: In order to obtain a more exact complication rate in the future, splenic injuries should be reported centrally. This is possible by sending a report of the complication by e-mail to splenicinjury_colonoscopy@web.de.

[Ultrasound education by simulator training high acceptance by ultrasound trainees of all qualification levels]. / Ultraschallausbildung am Ultraschallsimulator.

Ultrasound education improves by simulator training, however, the acceptance of ultrasound simulator training has not been investigated. Therefore we evaluated the participants response to simulator education during an ultrasound course of abdominal emergencies at an international ultrasound congress, at a regular ultrasound course and during courses at a regional hospital and an university hospital. Altogether, 62.3% of the participants judged the simulator image quality to be good. 84.3% considered the case selection to be good and 92.7% of the participants viewed the educational benefit to be good. 98.5% whished to have further ultrasound simulator courses to be developed and 95.3% of the participants opted for the integration of simulator training into the conventional ultrasound education.

Isolation and characterization of the human cellular myc gene product.

Antibodies against the product of the human cellular myc gene (c-myc) were prepared against a bacterially expressed human c-myc protein by inserting the ClaI/BclI fragment of the human c-myc DNA clone in an expression vector derived from pPLc24. These antibodies cross-react with viral-coded myc (v-myc) proteins from MC29 and OK10 viruses. Furthermore, IgGs specific for synthetic peptides, corresponding to the 12 carboxy-terminal amino acids of the human c-myc gene and 16 internal amino acids, were isolated. By use of the various myc-specific antisera or IgGs, a protein of Mr 64 000 was detected in several human tumor cell lines including Colo320, small cell cancer of the lung (417d), HL60, Raji, and HeLa. This protein is larger than the corresponding v-myc or chicken c-myc proteins from avian virus transformed cells or avian bursa lymphoma cells (RP9), both of which are proteins of Mr 55 000. The human c-myc protein is located in the nucleus of Colo320 cells, exhibits a half-life of about 15 min, and is expressed at significantly lower levels than the viral protein. The human c-myc protein was enriched about 3000-fold from Colo320 cells using c-myc-specific IgG coupled to Sepharose beads. The protein binds to double-stranded DNA in vitro, a reaction that can be inhibited to more than 90% by c-myc specific IgG.

Central venous access catheters: radiological management of complications.

A great variety of central venous access devices such as tunneled and non-tunneled central venous catheters (CVC) as well as port systems are implanted by interventional radiologists at an increasing rate. There are some possible immediate, early, and late complications related to the implantation technique, care, and maintenance of CVCs. This review will illustrate possible complications of CVCs and will discuss risk factors. Different strategies will be shown regarding the prevention and treatment of complications.