Herpes simplex virus immediate-early proteins ICP0 and ICP4 activate the endogenous human alpha-globin gene in nonerythroid cells

Globin genes are normally expressed only in erythroid cell lineages. However, we found that the endogenous alpha-globin gene is activated following infection of human fibroblasts and HeLa cells with herpes simplex virus (HSV), leading to accumulation of correctly initiated transcripts driven by the alpha-globin promoter. The alpha1- and alpha2-globin genes were both induced, but expression of beta- or zeta-globin genes could not be detected. Experiments using HSV mutants showed that null mutations in the genes encoding the viral immediate-early proteins ICP4 and ICP22 reduced induction approximately 10-fold, while loss of ICP0 function had a smaller inhibitory effect. Transient transfection experiments showed that ICP0 and ICP4 are each sufficient to trigger detectable expression of the endogenous gene, while ICP22 had no detectable effect in this assay. ICP4 also strongly enhanced expression of transfected copies of the alpha2-globin gene. In contrast, the adenovirus E1a protein did not activate the endogenous gene and inhibited expression of the plasmid-borne alpha2-globin gene. Previous studies have led to the hypothesis that chromosomal alpha-globin genes are subject to chromatin-dependent repression mechanism that prevents expression in nonerythroid cells. Our data suggest that HSV ICP0 and ICP4 either break or bypass this cellular gene silencing mechanism.

Xist-deficient mice are defective in dosage compensation but not spermatogenesis

The X-linked Xist gene encodes a large untranslated RNA that has been implicated in mammalian dosage compensation and in spermatogenesis. To investigate the function of the Xist gene product, we have generated male and female mice that carry a deletion in the structural gene but maintain a functional Xist promoter. Mutant males were healthy and fertile. Females that inherited the mutation from their mothers were also normal and had the wild-type paternal X chromosome inactive in every cell. In contrast to maternal transmission, females that carry the mutation on the paternal X chromosome were severely growth-retarded and died early in embryogenesis. The wild-type maternal X chromosome was inactive in every cell of the growth-retarded embryo proper, whereas both X chromosomes were expressed in the mutant female trophoblast where X inactivation is imprinted. However, an XO mouse with a paternally inherited Xist mutation was healthy and appeared normal. The imprinted lethal phenotype of the mutant females is therefore due to the inability of extraembryonic tissue with two active X chromosomes to sustain the embryo. Our results indicate that the Xist RNA is required for female dosage compensation but plays no role in spermatogenesis.

DNA hypomethylation can activate Xist expression and silence X-linked genes

Xist and other X-linked gene expression was examined by fluorescence in situ hybridization in cells of wild type and DNA methyltranferase (Dnmt) mutant embryos and embryonic stem (ES) cells to determine whether demethylation-induced Xist expression leads to inappropriate X chromosome inactivation. In undifferentiated ES cells low-level Xist expression was detected from the single active X chromosome (Xa) in male cells and on both Xa's in female cells. Upon differentiation Xist expression was detected only in female cells, in which Xist RNA colocalized with the entire inactive X chromosome (Xi). Differentiated Dnmt mutant ES cells or cells of mutant postgastrulation embryos showed aberrant patterns of Xist expression: Xist transcripts colocalized with the single X chromosome in male cells and with both X chromosomes in female cells. X-linked gene expression was not detected from chromosomes coated with Xist RNA. These results suggest that ectopic Xist expression, induced by DNA hypomethylation, may lead to the inactivation of X-linked genes. We conclude that Xist-mediated X chromosome inactivation can occur in the absence of DNA methylation, arguing that DNA methylation may be required to repress Xist expression for the maintenance of a transcriptionally active Xa. In differentiated Dnmt mutant ES cells the activation of Xist expression correlated with a dramatic increase in apoptotic bodies, suggesting that Xist-mediated X chromosome inactivation may result in cell death and contribute to the embryonic lethality of the Dnmt mutation.

Activation of expression of multiple subfamilies of human Alu elements by adenovirus type 5 and herpes simplex virus type 1

The nearly one million Alu repetitive elements in the human genome can be grouped into a number of subfamilies. Comparisons between subfamily consensus sequences suggest that Alu evolution is characterized by the sequential amplification and dispersal of a limited number of Alu founder sequences. The S, Sb and Sb1 subfamilies provide an example of such a related series of Alu subfamilies. We have previously demonstrated that adenovirus type 5 and herpes simplex virus type 1 activate RNA polymerase III transcription of endogenous Alu elements in HeLa cells. Here, we report that expression of Alu sequences belonging to the S, Sb and Sb1 subfamilies was activated following infection with these viruses. The data indicate that transpositionally inactive Alu elements can give rise to high levels of pol III transcripts in the presence of appropriate trans-acting factors and demonstrate that the class III promoters of a significant number and variety of Alu sequences are functional in vivo. Multiple subfamilies of Alu sequences were induced in transformed and non-transformed cell types, suggesting that induction of Alu expression may be part of the normal cellular response to viral infection.

[Cardioverter-defibrillator implantation in the heart catheterization laboratory--observations with 105 patients]

Today, we are facing an exponential increase in implantation of cardioverter defibrillators (ICD). The intraoperative and follow-up results are reported in 105 patients (pts) with ventricular tachyarrythmias who underwent ICD implantation in the catheterization laboratory. Fifty-seven pts (54%) hat their first ICD implant (G 1), whereas 46 pts (44%) underwent pulse generator replacement or electrode revision (2 pts, 2%) (G 2). In all pts, ICD implant or pulse generator replacement was performed under general anesthesia from the beginning. In 57/58 pts (98%) in G 1, ICD implantation was possible with a mean defibrillation threshold (DFT) of 13 +/- 8 joules. One patient hat a DFT of > 25 joules and ICD implantation was not achieved. This patient underwent epicardial lead implantation 1 day later. One patient in G 1 had a vessel rupture (v. subclavia) intraoperatively. During a mean follow-up of 5 +/- 2 (< 1-13) months, three pts (3%) died from congestive heart failure, 2, 4 and 6 months after device implantation. An infection occurred in 1 patient in G 2, 3 months after generator replacement. Our data show that in the majority of patients ICD implantation in the cath-lab is possible, safe, and the complication rate is low. Therefore, ICD implantation in the cath-lab can generally be recommended.

Cardioverter-defibrillator implantation in the catheterization laboratory: initial experiences in 48 patients

The exponential increase in cardioverter-defibrillator implantations has resulted in a need for safe implantations that do not require long waiting periods. We report intraoperative and follow-up results in 48 patients with ventricular tachyarrhythmias who underwent cardioverter-defibrillator implantation in the catheterization laboratory. Twenty-six (54%) patients had their first cardioverter-defibrillator implant (group 1), and 22 (46%) patients underwent pulse-generator replacement (group 2). In all patients, cardioverter-defibrillator implant or pulse-generator replacement was performed with the patient under general anesthesia. In 25 (96%) of 26 patients in group 1, cardioverter-defibrillator implantation was possible with a mean defibrillation threshold of 13 +/- 8 J. One patient had a defibrillation threshold of > 25 J, and therefore cardioverter-defibrillator implant was not achieved. This patient underwent epicardial device implantation 1 day later. Another patient in group 1 had vessel rupture (vena subclavia) intraoperatively. During a mean follow-up of 2 +/- 1 months, two patients died from congestive heart failure 2 and 4 months after device implantation. An infection occurred in one patient in group 2, 3 months after generator replacement. In conclusion, these data show that in the majority of patients cardioverter-defibrillator implantation in the catheterization laboratory is safe and has a low complication rate and therefore can generally be recommended.

[Emergency intubation with the Combitube in a patient with persistent vomiting]

Prompt establishment of a patient airway and effective ventilation are the major goals during initiation of cardiopulmonary resuscitation in patients with cardiac arrest. Endotracheal intubation is the definitive method to maintain an optimal airway. However, endotracheal intubation is not always possible, even for the skilled physician. The Combitube has been developed to overcome this disadvantage. Studies have proved the effectivity of ventilation with this device. A case is reported where a patient suffered from acute respiratory failure and attempts at endotracheal intubation failed due to continued vomiting rendering fibre-optical visualisation of the vocal cords impossible. Blind insertion of the Combitube led to successful ventilation, and hence replacement by an endotracheal airway could be performed without danger of aspiration.

Activation of RNA polymerase III transcription of human Alu elements by herpes simplex virus

We found that HSV infection of HeLa cells strongly induces RNA polymerase III transcription of endogenous human Alu elements, resulting in the accumulation of high levels of cytoplasmic RNAs initiated from Alu pol III promoters. Induction required viral protein synthesis and occurred during infection with a viral mutant bearing a null mutation in the immediate-early (IE) gene encoding ICP4, suggesting that one or more IE proteins are sufficient for activation. However, mutations in each of the other four IE genes had no effect on activation of Alu expression. We therefore conclude that HSV most likely encodes at least two proteins that are each sufficient to activate Alu transcription and that at least one of these is an IE protein other than ICP4.

Neuroendocrine phenotype differentiation in a hamster lung epithelial cell line under low oxygen pressure or after transformation by diethylnitrosamine

Oxygen pressure as low as 5% in the gas phase or 87 mmHg in the liquid phase induced various neuroendocrine cell (NEC) phenotypes in more than 80% of cells of a cloned fetal Syrian hamster lung epithelial cell line (M3E3/C3). Further, cells from a number of colonies transformed in an anchorage-independent manner by diethylnitrosamine (DEN) demonstrated a NEC phenotype. Since the cell line used is of a pluripotent stem cell type, both hypoxia and DEN appear to possess a potency for NEC phenotype induction.

Activation of RNA polymerase III transcription of human Alu repetitive elements by adenovirus type 5: requirement for the E1b 58-kilodalton protein and the products of E4 open reading frames 3 and 6

We found that transcription of endogenous human Alu elements by RNA polymerase III was strongly stimulated following infection of HeLa cells with adenovirus type 5, leading to the accumulation of high levels of Alu transcripts initiated from Alu polymerase III promoters. In contrast to previously reported cases of adenovirus-induced activation of polymerase III transcription, induction required the E1b 58-kDa protein and the products of E4 open reading frames 3 and 6 in addition to the 289-residue E1a protein. In addition, E1a function was not required at high multiplicities of infection, suggesting that E1a plays an indirect role in Alu activation. These results suggest previously unsuspected regulatory properties of the adenovirus E1b and E4 gene products and provide a novel approach to the study of the biology of the most abundant class of dispersed repetitive DNA in the human genome.

Plasma volume estimation using indocyanine green. A single intravenous injection method

The validity and reliability of plasma volume estimation using indocyanine green were investigated in five in vitro experiments and in three in vivo series. The in vitro measurements reflected real volumes with an error of about 1%. Comparative measurements in the same patients using indocyanine green or Cr51 labelled red cells differed by 1.7% (r = 0.97). The mean (SD) plasma volume difference between two successive plasma volume measurements using indocyanine green was 38 (43) ml (r = 0.99). Plasma volume measured before and about 7 min after a hyperosmolar saline bolus (100 ml, 1 molar) was increased by 223 (102) ml and 286 (49) ml when determined by indocyanine green and plasma protein changes respectively. Nevertheless, the necessity for central venous injection and arterial sampling restricts the possible application of the method to intra-operative or emergency care use.

[Inner ear deafness following lumbar puncture. A complication requiring patient education?]

Deafness after lumbar puncture has been reported occasionally. Until now this complication has been regarded as spontaneously reversible, but a more recent publication of three cases of irreversible hearing loss possibly caused by lumbar puncture casts doubt on this. It has been proposed that this complication should be included in the pre-operative information given to patients, but we oppose this proposal.

[Cerebral perfusion pressure in acute blood pressure decrease with hyperosmolar sorbitol in anesthesia conditions]

Osmotherapy with sorbitol during intracranial surgery caused a significant decrease in arterial blood pressure. It was shown that this sometimes very desirable reaction did not cause relevant decreases in cerebral perfusion pressure, but was on the contrary accompanied by an increase in cerebral perfusion pressure in patients with severely elevated ICP (greater than 30 mmHg). 8 patients were studied by measuring the arterial and intracranial pressure during intraoperative infusions of sorbitol 40% (3 ml/kg body weight). Our findings are explained by the simultaneous decrease in arterial and intracranial pressure. During intracranial surgery sorbitol can be used as the antihypertensive agent of choice for treating hypertensive dysregulation of arterial blood pressure in the initial phase of craniotomy before opening the dura.

Determination of circulating blood volume by measurement of indocyanine green dye in hemolysate: a preliminary study

In 8 emergency care patients blood volume was determined using Cr5I labelled erythrocytes and indocyanine green (ICG). Prior to measurement of ICG in blood with a spectrophotometer, the blood was hemolyzed with Triton-X. A close correlation of r = 0.97 between the Cr51 and the ICGTR-X estimates was found; the ICGTR-X volume was about 3% lower than the Cr51 volume. In five additional in vitro experiments the ICGTR-X method was found to reflect real volumes with an insignificant error of less than 1%. Blood volume determination with ICGTR-X cannot be applied in cases of circulatory failure. ICG should be administered in a dose of 0.5 mg/kg of body weight. For calibration purposes, a two point calibration curve (point 1: point of intersection of x and y axis; point 2: 5 mg ICG/1 of blood) is sufficient. From these preliminary experiments it is concluded that the ICGTR-X method is a rapid and simple technique of blood volume determination with multiple reproducibility which can be carried out in any clinical laboratory.

[Photoplethysmography evaluation of collateral blood flow before puncture of the dorsalis pedis artery]

Prior to cannulation of the dorsalis pedis artery the collateral circulation through the plantar arch should be examined to evaluate the consequence of an occlusion of this artery. Since the performance of the Allen's test is impossible for assessment of the plantar arch, another suitable technique has to be chosen. We selected the photoelectric plethysmography. Toe pulses were recorded with photoelectric plethysmography in 20 neurosurgical patients. The pulse amplitudes were measured before and during successive compression of the dorsalis pedis and the posterior tibial artery. Obvious decrease or absence of the pulse wave during compression of the dorsalis pedis artery is indicating an inadequate collateral circulation and cannulation of this artery seems not to be safe. In our study this occurred in 4 of 32 examined feet (12.5 percent). The photoelectric plethysmography has proved to be a simple and accurate means for assessment of collateral circulation.

Regulation of cellular genes transduced by herpes simplex virus

Previous studies demonstrated that the rabbit beta-globin gene is transcribed from its own promoter and regulated as a herpes simplex virus (HSV) early gene following insertion into the early HSV thymidine kinase gene in the intact viral genome (J. R. Smiley, C. Smibert, and R. D. Everrett, J. Virol. 61:2368-2377, 1987). We report here that the beta-globin promoter remained under early control after insertion into the late HSV gene encoding glycoprotein C. On the basis of these findings, we concluded that the beta-globin promoter is functionally equivalent to an HSV early-control region. We found that a transduced human alpha-globin gene was also regulated as an early HSV gene, while two linked Alu elements mimicked the behavior of HSV late genes. These results demonstrate that certain aspects of HSV temporal regulation can be duplicated by cellular elements and provide strong support for the hypothesis that the regulation of HSV gene expression can occur through mechanisms that do not rely on recognition of virus-specific temporal control signals.

[Chronic subdural hematoma following spinal anesthesia]

A chronic subdural hematoma was observed 4 weeks after spinal anesthesia. The 70-year-old patient complained of severe, long-lasting headache soon after lumbar puncture. The later symptoms of hemiparesis and aphasia were first misinterpreted as a cerebral vascular accident. After evacuation of the hematoma the patient recovered. Long-lasting, severe headaches after lumbar puncture may be caused by a chronic subdural hematoma, a very rare complication. Risk groups are elderly patients and alcoholics, but every age group can be affected, including parturient women who deliver under spinal anesthesia. The diagnostic procedure of choice is computerized tomography (CAT). The application of contrast medium might be necessary if the CAT scan appears suspicious for a hematoma with the same density as the brain tissue. Because this complication is so rare informing the patient before spinal anesthesia does not seem to be necessary. According to expert opinions, a connection between lumbar puncture and subdural hematoma should be possible. In elderly patients and alcoholics, a pre-existing subdural hematoma may be possibly present.

[Critical comments on reports of fatalities in hereditary fructose intolerance in adulthood from the viewpoint of neuroanesthesia]

In view of repeated communications in recent years reporting on lethal infusions of fructose or sorbitol in adults with hereditary fructose intolerance, the known statements on the incidence of 1:20,000 are critically analysed. The validity is relativated. The special indication for sorbitol as an osmotherapeutic preparation for lowering intracranial pressure is pointed out. A modified intravenous fructose tolerance test is suggested.

[Acute lowering of blood pressure by infusion of hyperosmolal sorbitol solution in brain operations. Dangerous adverse effect or favorable side effect?]

Osmotherapy with sorbitol 40% during intracranial surgery using neurolept analgesia usually produced acute decreases in arterial blood pressure. Haemodynamical measurements during intraoperative infusions of sorbitol in 97 patients showed a rapid decrease of arterial mean pressure from 91 to 72 mm Hg. In 22 of these patients cardiac output measurements were performed. Increases of cardiac index from 2.5 to 4.3 l/min x m2 could be found. The hypotensive side effect can be used for treatment of reactive arterial hypertension in neurosurgical patients during surgery where this therapy is advantageous per se because of its cerebral dehydrating effects. The decrease of blood pressure is obviously caused by peripheral vasodilatation. Cardiac disturbances were not observed. Other side effects, especially the danger of hereditary fructose intolerance are discussed.

[Nalbuphine in comparison with piritramid and placebo in postoperative pain therapy following intubation anesthesia with halothane. Side effects and effectiveness]

The aim of the study was a comparison of the side-effects and efficacy of nalbuphine, piritramide, and placebo in patients during recovery from halothane anesthesia.

METHODS

Neurosurgical (vertebral surgery) and otolaryngological patients (surgery of face and neck) were operated under halothane anesthesia. Postoperatively 20 patients received 20 mg nalbuphine, 21 patients 15 mg piritramide, and 19 patients 0.9% NaCl for pain therapy in a randomized and double-blind manner. Respiratory function was monitored by blood gas analysis, hemodynamic function by noninvasive measurements. The analgetic and sedative effects were estimated by the patients (visual analog scale) and the investigator (4-point scale). If the treatment was ineffective, the study was interrupted and a known analgesic was prescribed.

RESULTS

The noninvasively measured hemodynamic parameters were unchanged. On the other hand, in the nalbuphine group mean arterial pCO2 increased significantly (max. 55.4 mmHg after 20 min), over the piritramide group (max. 51.2 mmHg before treatment) and the placebo group (max. 55.1 mmHg before treatment). Drowsiness, in 8 patients in each of the treatment groups and 3 patients in the placebo group, was the most frequent side-effect. After nalbuphine the pain threshold was significantly higher than after treatment with piritramide and placebo. The study was interrupted because of inefficacy in no patients from the nalbuphine group, 2 patients from the piritramide group, and 6 patients from the placebo group. There were no differences in the sedative effects.

CONCLUSIONS

Nalbuphine seems to have better analgesic effects then piritramide. Both cause no hemodynamic alterations.(ABSTRACT TRUNCATED AT 250 WORDS)

[Lumbar epidural hematoma and spinal abscess following peridural anesthesia]

Epidural application of local anesthetics or opiates is commonly used for treatment of severe pain or arterial obstruction. We discuss two cases of complications following peridural anesthesia. As an acute complication, a lumbar epidural hematoma developed hours after placement of the catheter and caused sciatic pain and nearly complete paraplegia. The hemorrhage might have been promoted by heparinization. After decompressive hemilaminectomy the patient recovered but was disabled by a persistent paresis. The second patient suffered from renal failure, arterial obstruction, and phantom limb pain. A peridural catheter was kept in place for 6 weeks. Five months later the patient developed severe sciatica. Spinal computed tomography showed compression of the cauda at the L4/5 level (Fig.4) caused by an abscess that was opened and drained. After insertion of a gentamicin - PMMA - chain (Septopal), the wound healed primarily but the patient suffered from persistent pain. The incidence of vessel puncture after insertion of a peridural catheter is about 1%-10%. The risk of hemorrhage, perforation of the dura, and nerve root irritation is increased in scoliotic or elderly patients with a narrow spinal canal. Persistent pain after removal of the catheter is the most important sign. Although paraplegias following peridural catheterization can occur without anticoagulants, even low-dose heparinization is potentially dangerous. The risk of infectious complications after long-term peridural catheterization may be up to 20%. Hematogenous metastatic infection is more common in patients with malignancies or multiple risk factors than continuous immigration of bacteria. Epidural hematomas and spinal abscesses can cause disability and persistent neurological deficit in spite of aggressive surgical and antibiotic therapy.

[Anesthesiological care of female patients with cerebrovascular aneurysms in pregnancy]

This is a report on a patient who suffered subarachnoid haemorrhage from an aneurysm of the a. cerebri media during the 28th week of pregnancy. The aneurysm was clipped under neuroleptanalgesia. Besides monitoring of heart rate, blood pressure and central venous pressure as well as the treatment parameters including end-expiratory CO2, the foetal heart rate was deduced by Doppler sonography. She was hyperventilated intraoperatively with a paCO2 of 3.8-4.1 kPa. During the actual aneurysm surgery, artificial hypotension by 20 mmHg to b.p. values around 100/160 mmHg was initiated by means of nitroglycerin. It is evident from the literature compiled on this occasion that it is mandatory to monitor foetal heart rate during controlled hypotension in pregnancy. Sodium nitroprusside should not be used to initiate artificial hypotension during pregnancy, since it may result in toxic cyanide levels in the foetus. As usual in neurosurgery, hyperventilation can be performed also during pregnancy, since placental blood flow decreases only if the CO2 concentration drops to a very low level.

[The so-called venous air embolism: historical aspects and current diagnosis, prophylaxis and therapy]

The so-called venous air embolism is known as a complication not only of surgical operations but also of other procedures. Two conditions must be fulfilled: a lesion of a non collapsible vein; and a pressure gradient from outside to inside the vein, as occurs for instance during puncture of a large vein in a hypovolemic patient. Air entry into veins is a frequent occurrence during neurosurgery in sitting patients, and thus most diagnostic, prophylactic, and therapeutic innovations were proposed by neuroanesthetists. Due to advances in technique, truly dangerous cases of so-called venous air embolism during neurosurgery in patients in the sitting position are very rare.

[Mycotic intracranial aneurysm in infective endocarditis of the mitral valve]

A 20-year-old woman suffering from mitral valve endocarditis due to streptococcus faecalis infection after blunt trauma and splenectomy complained of severe headache 18 days later. Cerebral angiography showed a left posterior artery aneurysm. A craniotomy was performed and the aneurysm could be successfully removed. The postoperative neurological status showed a mild transient right hemiparesis. The patient underwent mitral valve replacement with a St. Jude-Medical prosthesis 14 days after brain surgery. The patient was in stable neurologic and hemodynamic conditions at the time of discharge 3 weeks after valve replacement.

[Transient low frequency hearing loss and facial paralysis following spinal anesthesia. A case report]

Facial paresis and low frequency hearing loss was observed 16 days after spinal anaesthesia in a 22 years old male patient. Both disturbances disappeared within a short time of bed rest as the only therapy. The hearing loss showed the typical picture which we have observed in the last few years as a complication of spinal anaesthesia. The facial paresis which appeared at the same time could well be caused by low of cerebrospinal fluid pressure due to leakage via the puncture hole.

[Anaphylactoid shock following Alloferin]

Reports of allergic complications related to Alloferin are very infrequent. We report a case of anaphylactoid reaction to this drug. The diagnosis was confirmed by intradermal testing.

[Anesthetic problems and complications in the thermocoagulation of Gasser's ganglion]

We report about hypertensive crises, cardial arrhythmia and respiratory complications in 47 patients undergoing thermocoagulation of the gasserian ganglion. Therapeutic proposals are discussed.

[Transient low frequency hearing loss following spinal anesthesia]

Hearing loss after spinal anaesthesia is very seldom reported in the literature. After having seen such a case we studied prospectively 100 patients with urological operations under spinal anaesthesia. We found 3 patients having a typical picture of a transient hearing loss in the low frequency range (30 dB). This disturbance was reversible in short time without special therapy.