Delayed occurrence of traumatic aortic dissection? Biomechanical considerations and literature.

Chronic aortic dissections and pseudoaneurysms caused by chest trauma are rare and generally have to be critically distinguished from non-traumatic dissections and aneurysms. We present a well-documented case of a post-traumatic aortic dissection that ruptured about 9 months after chest trauma. A motorcyclist sustained fractures of the forearm and chest trauma with paravertebral rib serial fractures and hemopneumothorax. Nine months after the accident, echocardiography revealed a pseudoaneurysm that ruptured 3 months later and 1 month prior to the planned surgery. An autopsy showed pericardial tamponade following a rupture of the dissected aorta. Accident scene documentation was consistent with a head-on collision of the motorcycle against the left front side of the car. The relative speed was about 55 km/h. Aggravation of unspecific symptoms after discharge, initial CT imaging, and the absence of atherosclerosis or medial necrosis hold for a post-traumatic genesis of the dissection in our case. Initially, the accident insurance company rejected the regulation. In the second instance, they revised rejection based on our interdisciplinary expert opinion.

[Prostate cancer]. / Prostatakarzinom.

For many clinical issues regarding prostate cancer magnetic resonance imaging (MRI) is gaining increasing importance for prostate diagnostics. The high morphological resolution of T2-weighted sequences is unsurpassed compared to other imaging modalities. It enables not only the detection and localization of prostate cancer but also allows the evaluation of extracapsular extensions. Functional MRI methods, such as diffusion-weighted imaging (DWI), dynamic contrast-enhanced (DCE) MRI and proton magnetic resonance spectroscopy ((1)H-MRS) increase the specificity and to a lesser extent, the sensitivity of diagnostics. In accordance with the interdisciplinary S3 guidelines, prostate MRI is recommended for patients with at least one negative biopsy for cancer detection. According to the guidelines areas suspected of being cancerous should be selectively biopsied in addition to the systematic biopsy. The transmission of findings about the suspected tumor areas according to the structured PI-RADS classification system has proven its worth. The localization and staging of prostate carcinoma is best achieved with the help of MRI and is recommended in the S3 guidelines especially for tumors with a clinical stage cT3/4 or with a Gleason grading system score ≥8. In addition to these applications MRI is mainly used under study conditions for local recurrence or active surveillance.

[Refractory thrombotic thrombocytopenic purpura]. / Therapierefraktäre thrombotisch-thrombozytopenische Purpura.

Thrombotic thrombocytopenic purpura (TTP) remains a serious illness with potentially life-threatening complications. The following case of a TTP patient describes a serious relapse with exacerbation in spite of adequately initiated therapy and highlights the necessity of interdisciplinary expertise in the treatment of the disease.

Heat Denaturation Profiles of Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase (Rubisco) and Rubisco Activase and the Inability of Rubisco Activase to Restore Activity of Heat-Denatured Rubisco.

We compared the heat-denaturation profiles of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and Rubisco activase and further examined the ability of Rubisco activase to restore the activity of heat-denatured Rubisco originally reported (E. Sanchez de Jimenez, L. Medrano, and E. Martinez-Barajas [1995] Biochemistry 34: 2826-2831). Rubisco was heat-treated in both the carbamylated and uncarbamylated forms and in the presence and absence of 10 mM dithiothreitol (DTT). Both forms were highly resistant to heat denaturation and further protection was gained in the presence of DTT. A 50% loss in total activity occurred after 1 h at 57.5 and 55.2[deg]C for uncarbamylated Rubisco and at 60.2 and 59.6[deg]C for carbamylated Rubisco, in each case with and without DTT, respectively. In contrast, Rubisco activase lost 50% activity after only 5 min at 33[deg]C and the loss in activity was not affected by the presence of Rubisco. When Rubisco, heat-denatured to various extents, was incubated at room temperature with Rubisco activase or bovine serum albumin as a control, Rubisco activase did not have a significant specific ability to restore Rubisco activity. We conclude that Rubisco activase alone does not have the ability to restore the activity of heat-denatured Rubisco and is unlikely to protect or restore Rubisco activity from heat denaturation in vivo because it is more heat-labile than Rubisco.

Phase I and pharmacokinetic study of tirapazamine (SR 4233) administered every three weeks.

Tirapazamine (SR 4233; 3-amino-1,2,4-benzotriazine-1,4-di-N-oxide) is a bioreductive agent exhibiting up to 200 x greater toxicity for hypoxic cells as compared to oxygenated cells. In murine studies, a selective increase in tumor kill was observed when tirapazamine was coadministered with other agents, notably cisplatin. A Phase I study of single-agent tirapazamine administered i.v. every 3 weeks was conducted to determine the toxicity of a schedule for use with systemic chemotherapy. A total of 28 patients were given 50 courses of tirapazamine at doses ranging from 36-450 mg/m2. No tumor responses were observed. Reversible deafness and tinnitus were dose-limiting, with ototoxicity observed in 1 of 6 patients treated at 330 mg/m2, 1 of 4 patients treated at 390 mg/m2, and 3 of 3 patients treated at 450 mg/m2. Muscle cramps, nausea, and vomiting were also observed. Pharmacokinetic studies revealed a greater than dose-proportional increase in the area under the plasma concentration x time curve (AUCs) of the two major metabolites. Patients who developed ototoxicity generally showed higher plasma AUC values for the parent drug and metabolites. The mean plasma tirapazamine AUC at 330 mg/m2 was 1026.5 microgram/ml x min (range 863. 8-1252.3), but no pharmacokinetic data are available for the solitary patient who developed otoxicity at this dose level. These AUC values were in the (estimated) range required for therapeutic effect in murine studies. Ototoxicity was not observed when the AUC of tirapazamine was equal to or less than 1252 microgram/ml x min. The dose of 330 mg/m2 was therefore chosen as an appropriate level for combination chemotherapy studies.

Phase II trial of 5-fluorouracil and recombinant interferon alfa-2B in metastatic colorectal carcinoma.

Between February 1990 and April 1991, 59 previously untreated patients with progressive and/or symptomatic metastatic colorectal carcinoma were enrolled in a phase II study of 5-fluorouracil (5-FU) and interferon alfa-2b (IFN-alpha). 5-FU 750 mg/m2/day was administered as continuous infusion for 5 days, then weekly in a dose of 750 mg/m2 as intravenous push injection starting on day 15. IFN-alpha 9 MU was given subcutaneously three times a week. Treatment was given for a maximum of 6 months. 55 patients are evaluable for response and 51 for toxicity. 17 patients (31%) achieved a partial remission, 15 (27%) had stable disease and 21 patients (38%) had progressive disease. Median duration of remission was 5 months and median survival for all patients 10 months. Toxicity was important with two treatment-related deaths and severe leukopenia, fever, diarrhoea and mucositis in about one third of the patients. In our opinion, this regimen is effective but rather toxic in metastatic colorectal carcinoma.

O3 -induced degradation of Rubisco protein and loss of Rubisco mRNA in relation to leaf age in Solanum tuberosum L.

The effect of ozone (O3 ) on Rubisco degradation was investigated by dark incubation of potato plants (Solanum tuberosum L. cv. Norland) following exposure to charcoal-filtered air or 0.30µl l-1 O3 for 6 h. Rubisco small subunit (rbcS) mRNA levels declined dramatically in control foliage within 10.16 h of dark incubation; thus declines in Rubisco protein following a 48-h dark period were ascribed to proteolytic degradation. Foliage sampled from the 4th and 6th leaves from the apex, designated immature and mature, respectively, showed no effect of O3 on Rubisco protein content immediately following the exposure. However, the decline in Rubisco quantity during the dark incubation was significantly enhanced by prior treatment with O3 in the mature leaves. The immature leaves sustained a similar decline in Rubisco quantity in both O2 and control treatments. O3 had a significant effect on the relative quantity of rbcS mRNA in the immature leaves (sampled immediately following the O3 exposure). Levels of rbcS mRNA in mature leaves and Rubisco large subunit (rbcL) mRNA in both leaf ages were not significantly affected by O3 , There was no effect of O3 , on Rubisco quantity in immature or mature leave's of plants maintained in the greenhouse under a 16 h photoperiod far 48 h following the exposure. Thus the effect of short-term O3 exposure on processes affecting Rubisco synthesis and degradation may have been transient, and a more prolonged exposure would he necessary to effect a decline in Rubisco protein quantity in plants grown under a 16 h photoperiod. We concluded that O3 caused enhanced degradation of Rubisco in mature leaves of plants induced to senesce by dark incubation following O3 exposures. The potential for O3 -induced reduction in synthesis of Rubisco also exists.

Effects of ethylenediurea (EDU) on ozone-induced acceleration of foliar senescence in potato (Solanum tuberosum L.).

Experiments were conducted to examine the effects of the anti-ozonant ethylenediurea (EDU) and chronic ozone (O3) exposure on leaf physiology and senescence in an O3-sensitive potato cultivar (Solanum tuberosum L. cv. Norland). A dose-response experiment showed that an EDU concentration of 15 mg l(-1) soil (given as a soil drench) provided complete protection from accelerated foliar senescence induced by exposure to 0.1 microl l(-1) O3 for 5 h day(-1) for 11 days. EDU doses of 45 and 75 mg active ingredient l(-1) soil also gave protection but were associated with symptoms of toxicity and delayed senescence. In further experiments, plants were given 0 or 15 mg EDU l(-1) soil and exposed to clean air or 0.1 microl l(-1) O3 for 5 h day(-1) for 14 days. Chronic O3 exposure in the absence of EDU resulted in accelerated foliar senescence, characterized by early declines in net photosynthesis and Rubisco quantity in O3-treated plants relative to controls. EDU in the presence of O3 gave complete protection against symptoms of accelerated senescence. Senescence was not delayed in plants that received EDU in the absence of O3, and no symptoms of EDU toxicity were evident. The results suggest that EDU-induced tolerance to O3 was not based on 'anti-senescent' properties of this anti-ozonant.

Occurrence of human papillomavirus DNA types 16 and 18 (HPV-16/18) in cervical smears as compared to cytological findings.

Cervical smears from 2336 women were examined for the presence of HPV-16/18 by dot-blot hybridization using 32P-labeled HPV-16/18 DNA under high stringency conditions. The hybridization data were compared with cytological findings classified according to Papanicolaou. The ages of the patients ranged from under 20 to over 70 years. Ninety-eight (4.4%) of the 2237 cytologically normal cervical samples (Pap I and II) were HPV-16/18 positive. Thirteen out of 32 (40.6%) samples showing signs of mild and moderate dysplasia (Pap IIID) were found to be HPV-16/18 positive. In 5 out of 7 (71.4%) samples from women with severe dysplasia or carcinoma in situ (Pap IV) and in 9 out of 25 (32.1%) samples from patients with invasive cervical carcinoma (Pap V) HPV-16/18 DNA was detected. Thirty-two smears were from women with severe unspecific cervical inflammation (Pap III). Two (6.2%) out of them were HPV-16/18 positive. Normal smears showed an apparent age-dependent pattern of HPV-16/18 positivity with a peak prevalence of 10.6% among women younger than 20 years old. The majority of premalignant lesions was detected among women younger than 40 years old; whereas all invasive lesions were from women older than 39 years. Compared to the HPV-16/18 prevalence rate in normal smears, abnormal smears harbored HPV-16/18 DNA approximately 9 times more frequently. This finding supports the hypothesis that HPV-16/18 may be involved in the development of cervical cancer.

Biochemical and molecular basis for impairment of photosynthetic potential.

Ozone induces reductions in net photosynthesis in a large number of plant species. A primary mechanism by which photosynthesis is reduced is through impact on carbon dioxide fixation. Ozone induces loss in Rubisco activity associated with loss in concentration of the protein. Evidence is presented that ozone may induce oxidative modification of Rubisco leading to subsequent proteolysis. In addition, plants exposed to ozone sustain reduction in rbcS, the mRNA for the small subunit of Rubisco. This loss in rbcS mRNA may lead to a reduced potential for synthesis of the protein. The regulation of O3-induced loss of Rubisco, and implications of the decline in this protein in relation to accelerated senescence are discussed.

Overexpression of deltaEmBP, a truncated dominant negative version of the wheat G-box binding protein EmBP-1, alters vegetative development in transgenic tobacco.

As a first step toward elucidating the in vivo function of plant bZIP proteins and their related G-box cis elements, we have introduced a dominant negative inhibitor of G-box-dependent transcriptional activation into tobacco plants by transforming them with a truncated EmBP-1 gene (deltaEmBP) containing the DNA binding and dimerization domains under the control of the CaMV 35S promoter. Five independent lines of transgenic plants expressing deltaEmBP were identified, as demonstrated by immunodetection of the transgenic protein in leaf extracts, and the ability of the protein to bind a target G-box DNA sequence. The transgenic plants exhibited an abnormal phenotype characterized by interveinal chlorosis, growth inhibition and weakening of stems and petioles, the severity of which positively correlated with deltaEmBP expression and G-box DNA binding capability. Furthermore, development of chlorosis and growth inhibition was dependent on growth irradiance. Low light promoted the development of interveinal chlorosis and growth inhibition in the transgenic plants, whereas high light conditions led to near-complete amelioration of the abnormal phenotype. Transgenic plants under both light regimes showed signs of impaired stem and petiole function which was not observed in wild-type tobacco. RhcS gene expression was not significantly altered by deltaEmBP expression, suggesting that down-regulation of this gene was not responsible for the altered phenotype. The results suggest that G-box elements specific for the EmBP-1 class of bZIP proteins have an important developmental function in vegetative plant tissues, and that the trans-dominant negative mutant approach is a useful tool for continued in vivo functional analysis of bZIP transcription factors and their corresponding cis elements in plants.

Growth and photosynthesis under high and low irradiance of Arabidopsis thaliana antisense mutants with reduced ribulose-1,5-bisphosphate carboxylase/oxygenase activase content.

Photosynthesis and growth to maturity of antisense ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activase Arabidopsis thaliana with reduced concentrations of activase relative to wild-type (Wt) plants were measured under low (200 mumol m-2 s-1) and high (600 mumol m-2 s-1) photosynthetic photon flux density growing conditions. Both growth and photosynthesis were significantly reduced in an Arabidopsis clone (R100) with 30 to 40% Wt activase, an effect that was more pronounced in high light. The aboveground biomass of the antisense clone R100 reached 80% of Wt under low light and 65% of Wt under high light. Decreased growth in the antisense plants was attributed to reduced relative rates of growth and leaf area expansion early in development; all plants attained similar values of relative rates of growth and leaf elongation by 21 d after planting. Reductions in photosynthesis were attributed to decreased Rubisco activation in the antisense plants. Rubisco constituted about 40% of total soluble protein in both Wt and clone R100 under both light regimes. Activase content was 5% and 1.4% of total soluble protein in Wt and clone R100, respectively, and also was unaffected by growth irradiance. The stoichiometry of Rubisco to activase was estimated at 20 Rubisco active sites per activase tetramer in Wt Arabidopsis and 60 to 80 in the transgenic clone R100. We conclude that Wt Arabidopsis does not contain Rubisco activase in great excess of the amount required for optimal growth.

[Prevalence of hepatitis C virus in poly-transfused patients with hematologic and oncologic diseases]. / Prävalenz des Hepatitis-C-Virus bei polytransfundierten Patienten mit hämatologischen und onkologischen Erkrankungen.

Patients with hematological and oncological diseases often require intensive, supportive hematotherapy due to the underlying disease or chemo-/radiotherapy. As a consequence, they had an increased transfusion-associated risk of hepatitis C virus infections (non-A, non-B-posttransfusion hepatitis) until 1989-1990, when specific and sensitive HCV antibody tests became available. This is confirmed by our study of 'first' and 'second' generation (1.0 and 2.0) anti-HCV EIAs against structural and non-structural (NS) antigen-determinants. Ten of 101 patients (10.9%) were anti-HCV positive in 2.0 tests. HCV antibodies were detected more often by 2.0 EIAs and the new HCV-immunoblot (4-RIBA), than by 1.0 EIAs. In this respect, the patients' serological HCV profile differs from that of healthy blood donors, which display a prevalence of NS-antibodies.

In vivo pharmacology and anti-tumour evaluation of the tyrphostin tyrosine kinase inhibitor RG13022.

Amplification and increased expression of many growth factor receptors, including the epidermal growth factor receptor (EGFR), has been observed in human tumours. One therapeutic strategy for overcoming EGF autocrine control of tumour growth is inhibition of EGFR protein tyrosine kinase (PTK). A series of low molecular weight molecules have been identified which inhibit the EGFR PTK in vitro and demonstrate antiproliferative activity against human cancer cell lines with high expression of EGFR. A significant growth delay in squamous cancer xenografts has been reported for one of these compounds, the tyrphostin RG13022. Based on these encouraging results, we sought to confirm the activity of RG13022 in vivo and relate the effects to the in vivo plasma disposition. RG13022 and three additional peaks were detected by HPLC following intraperitoneal administration of 20 mg kg-1 RG13022 in MF1 nu/nu mice. RG13022 demonstrated rapid biexponential elimination from plasma with a terminal half-life of 50.4 min. RG13022 plasma concentrations were less than 1 microM by 20 min post injection. A primary product was identified as the geometrical isomer (E)-RG13022. Both RG13022 and its geometrical isomer inhibited DNA synthesis in HN5 cells after a 24 h in vitro incubation (IC50 = 11 microM and 38 microM respectively). Neither RG13022 nor its geometrical isomer displayed significant cytotoxicity. RG13022 had no influence on the growth of HN5 tumours when administered chronically, starting either on the day of tumour inoculation or after establishment of tumour xenografts. The rapid in vivo elimination of RG13022 has potential significance to the development of this and other related tyrphostin tyrosine kinase inhibitors, as plasma concentrations fell below that required for in vitro activity by 20 min post injection. The lack of in vivo tumour growth delay suggests that a more optimal administration schedule for RG13022 would include more frequent injections or continuous administration. An improved formulation for RG13022 is therefore required before further development of this or other similar protein tyrosine kinase inhibitors can be made. Alternative strategies should also be sought which display longer lasting in vivo exposures.