Introduction into fetal rat brain cells of a replication-defective retroviral vector harboring v-Ha-ras and v-gag-myc rapidly causes the induction of highly malignant undifferentiated neuroectodermal tumors following transplantation into the brains of syngeneic hosts [Wiestler, et al. (1992) Cancer Res. 52: 3760–3767]. In the present study, we have investigated the modulating effect of the developmental stage of neural target cells and of the dose of the retroviral vector used in the grafting experiments. Exposure of fetal cells from embryonic day (E)12 or E14 produced a 100% incidence of malignant neuroectodermal tumors which led to the death of recipient animals after a median latency period of 32 days. A 100-fold reduction of the virus dose from 2.062×106 to 2.062×104 focus-forming units/ml resulted in a lower tumor incidence of 25%. Of six neural grafts exposed to v-Ha-ras and v-myc at E16, only one showed evidence of tumorigenesis (low-grade astrocytoma and hemangioma). All other transplants were morphologically normal for observation periods of 26 weeks, indicating a marked loss of transforming activity of ras and myc in more advanced stages of brain development. In retrovirus-exposed donor cells which caused the development of neural tumors in recipient rats, malignant transformation was also evident during culture in vitro, usually after 9–12 days. Oncogene complementation was also studied in the newborn rat brain. After microinjection of the retroviral vector into the brain at postnatal day (P)0, P1 and P3, 5 out of 20 animals (25%) developed a total of seven brain tumors. Histopathologically, three of these neoplasms were malignant neuroectodermal tumors which, in contrast to those induced in fetal brain transplants showed evidence of focal glial and/or neuronal differentiation. In addition, we observed one oligodendroglioma, two hemangiomas and a malignant hemangioendothelioma. These data indicate that neural precursor cells and endothelia of the rat brain represent the major target cells for the complementary action of ras and myc and that the use of target cells from later developmental stages (E16 and postnatal) leads to the induction of both primitive and more differentiated neoplasms.These studies were supported by the Fonds zur Förderung der wissenschaftlichen Forschung in Österreich (Erwin Schrödinger fellowship, JO501-MED), by the Swiss National Science Foundation and by the Cancer League of the Kanton of Zürich 相似文献
Retrosternal dislocations of the clavicle have been reported previously in adults throughout the orthopedic literature. However, in children few cases have been noted in either the pediatric, emergency, or orthopedic literature. The potential for great vessel injury as well as acute airway compromise makes the retrosternal disruption of the sternoclavicular joint a surgical emergency that must be diagnosed quickly. Diagnosis is enhanced by the cephalic tilt view and by computed tomography (CT scan), as planar x-ray and tomography do not always reveal this potentially life-threatening condition. Surgical consultation must be sought acutely; however, management may need to begin prior to definitive repair. Emergency management begins by suspecting the injury, and with immediate airway and circulatory support for the patient. 相似文献
Background: Neuraxial blockade is used as primary anesthetic technique in one third of surgical procedures. The authors tested whether bisoprolol would protect patients at risk for cardiovascular complications undergoing surgery with spinal block.
Methods: The authors performed a double-blinded, placebo-controlled, multicenter trial to compare the effect of bisoprolol with that of placebo on 1-yr composite outcome including cardiovascular mortality, nonfatal myocardial infarction, unstable angina, congestive heart failure, and cerebrovascular insult. Bisoprolol was given orally before and after surgery for a maximum of 10 days. Adrenergic receptor polymorphisms and safety outcome measures of bisoprolol therapy were also determined.
Results: A total of 224 patients were enrolled. Spinal block could not be established in 5 patients. One hundred ten patients were assigned to the bisoprolol group, and 109 patients were assigned to the placebo group. The mean duration of treatment was 4.9 days in the bisoprolol group and 5.1 days in the placebo group. Bisoprolol therapy reduced mean heart rate by 10 beats/min. The primary outcome was identical between treatment groups and occurred in 25 patients (22.7%) in the bisoprolol group and 24 patients (22.0%) in the placebo group during the 1-yr follow-up (hazard ratio, 0.97; 95% confidence interval, 0.55-1.69; P = 0.90). However, carriers of at least one Gly allele of the [beta]1-adrenergic receptor polymorphism Arg389Gly showed a higher number of adverse events than Arg homozygous (32.4% vs. 18.7%; hazard ratio, 1.87; 95% confidence interval, 1.04-3.35; P = 0.04). 相似文献
Intestinal thermophilic Campylobacter species produce stable patterns when subjected to bacterial restriction endonuclease DNA analysis (BRENDA); this technique is therefore of considerable value in epidemiological studies. BRENDA was used to examine thermophilic Campylobacter species from humans, wild and domestic animals. One hundred and ninety-four (61%) of 316 isolates of Campylobacter jejuni from humans had BRENDA patterns which could be matched to those of animal isolates. Poultry appear to be a major source of infection for C. jejuni in humans with nearly half (49.7%) of the human isolates giving patterns which were indistinguishable from those isolated from poultry. A total of 60 BRENDA types were identified from 316 human isolates and 11 of these had the same pattern as those isolated from poultry. One of the three Campylobacter coli BRENDA types recovered from poultry was indistinguishable from a human isolate type. Pigs appear to be only a minor source of C. coli infection for humans in New Zealand. Rats were found to be infected with strains of C. jejuni with BRENDA patterns indistinguishable from those infecting humans, poultry and a horse. None of the 102 isolates of Campylobacter species from wild birds gave BRENDA patterns similar to those of isolates from humans. 相似文献
Zusammenfassung Wir berichten fiber die Doppler-sonographischen Ergebnisse bei 33 Patienten mit einer Anastomose zwischen der A. temporalis superficialis and der A. cerebri media. Die Indikation zur Bypass-Operation beinhaltete rezidivierende TIA oder ein kurz zuvor erworbenes leichtes neurologisches Defizit bei angiographischem Nachweis einseitiger oder beidseitiger tiefer Obliterationen der A. carotis interna und hochgradiger Stenosen oder Verschlüsse im distalen Abschnitt der A. carotis interna bzw. im proximalen Abschnitt der A. cerebri media. Die Funktionsfahigkeit der Anastomose wurde überpriift durch die Berechnung der modifizier ten Pourcelot-Indices (relative enddiastolische Strömungsgeschwindigkeit) der A. temporalis superficialis praeauriculär und am Bohrlochrand Bowie durch den EinfluB der intermittierenden Kompression des den Bypass-versorgenden Gefäßes auf den modifizierten Pourcelot-Index der ipsilateralen A. carotis communis. Bei allen Patienten mit funktionsfahigen Anastomosen, definiert durch einen modifizierten Pourcelot-Index von zumindest 0,20 am Bohrlochrand, kam es zu einer Reduktion dieses Parameters um durchschnittlich 0,08 an der A. carotis communis bei kurzfristiger Kompression des den Bypass-versorgenden Astes. Bei den 18 Patienten mit unilateraler Obliteration der A. carotis interna war der Bypass über-wiegend dann funktionsfähig, wenn die summierten modifizierten Pourcelot-Indices der verbliebenen hirnversorgenden Gefäße um zumindest 10% gegenüber einem vergleichbaren Normalkollektiv reduziert waren. Das Vorhandensein bzw. das Fehlen von Ophthalmica-Kollateralen hatte dabei keinen Einfluß auf den Prozentsatz der funktionsfahigen Anastomosen in diesen Untergruppen. Bei den vier Patienten mit bilateraler Obliteration der A. carotis interna war die angelegte Anastomose in jedem Fall funktionsfähig, während die Hälfte der Patienten mit Stenosen and Verschlüssen im distalen Abschnitt der Carotisstrombahn nur eine ungeniigende Bypass-Funktion zeigten. Die zwei Patienten mit einer Mediahauptstammstenose bzw. -obliteration hatten Indices von 0,45 bzw. 0,46 am Bohrlochrand als Hinweis auf die Funktionstüchtigkeit. Wir Bind der Auffassung, daß man mittels Doppler-sonographischer Kriterien die Funktionsfahigkeit einer Temporalis superficialis-Cerebri media-Anastomose überprüfen kann. Der praeoperativ berechnete summierte modifizierte Pourcelot-Index der verbliebenen hirnversorgenden Arterien kann zumindest bei uni- and bilateraler Internaobliteration als zusatzlicher Parameter herangezogen werden, um die Indikation zur Bypass-Operation zu klären. 相似文献
Areas of a high density university housing cooperative were randomly photographed following reports of decreased child supervision and increased potential for childhood poisoning and injury. A slide show was developed using these actual settings which revealed potential exposure to multiple toxic chemicals. This show was presented to the residents and demonstrated the high risk situations. Residents discovered that toxic chemicals were present in their own living environment, that many routes of exposure were possible and the high susceptibility of children during unsupervised play. As a result of this educational program, a poison prevention policy was approved with subsequent visible improvement in the community awareness and environment. This pictorial approach is a useful method for educating residents of a high density housing development about potential poisonings in their home environment and may be applied to other similar settings. 相似文献
OBJECTIVE: To review the technique, indications, and common imaging findings regarding saline infusion sonohysterography. METHODS: The literature on saline infusion sonohysterography was reviewed. Pertinent images from our institution are presented to illustrate common imaging findings. RESULTS: From the literature review, we summarize the various clinical scenarios in which saline infusion sonohysterography is useful and give examples from our clinical practice. CONCLUSIONS: Saline infusion sonohysterography is a useful procedure for evaluation of endometrial and subendometrial abnormalities. 相似文献