Biomedical subjects

M Ehrlich

Publications and source records attributed to M Ehrlich.

At least 73 records · Page 4Linked to original sources

PubMed1997

The use of profound hypothermia and circulatory arrest in operations on the thoracic aorta.

OBJECTIVE: This retrospective study reviews the contemporary surgical outcome of our patients undergoing operations on thoracic aneurysms in deep hypothermic circulatory arrest. METHODS: Between January 1989 and February 1995, 279 patients were operated on in our institution on various portions of the aorta. In 143 patients (97 male, 46 female), deep hypothermia and circulatory arrest were used as the standard operative technique. Patients age ranged from 16 to 83 years (mean 55). Final indication for operation was dissection Type A in 80 patients (61 acute, 19 chronic), dissection Type B in 21 patients (17 acute, 4 chronic) and atherosclerotic aneurysms in 42 patients (11 acute, 31 chronic). 16 patients were operated under preoperative unstable hemodynamic conditions, 6 patients had been resuscitated preoperatively. Surgical technique included cardiopulmonary bypass with femoral artery cannulation. For added cerebral protection all patients received Cortisone and barbiturates right before circulatory arrest (confirmed by 0-EEG). The segment of the aorta containing the area with the aneurysm, was resected and replaced with a tubular albumin coated graft. RESULTS: The 30-day mortality was 31.15% (19/61) in the acute and 23.52% (4/19) in the chronic type A dissection group, 35.29% (6/17) in the acute and 25% (1/4) in the chronic type B group, 36.3% (4/11) in the acute and 22.58% (7/31) in the chronic atherosclerotic group. Causes of postoperative death in order of frequency were: multiorgan failure (n = 15), myocardial failure (n = 13), bleeding (n = 4), sepsis (n = 4), myocardial infarction (n = 3) and stroke (n = 2). CONCLUSION: Despite rather high mortality rates in the acute aneurysm groups, the technique of profound hypothermic circulatory arrest represents a relatively safe method for operations on the thoracic aorta.

Adolescent↗

PubMed1997

Preferential induction of chromosome 1 multibranched figures and whole-arm deletions in a human pro-B cell line treated with 5-azacytidine or 5-azadeoxycytidine.

5-Azacytidine (azaCR) causes genomic demethylation and decondensation of juxtacentromeric heterochromatin in chromosomes 1, 9, and 16. We determined the karyotypes of a pro-B cell line (FLEB14) treated with azaCR or its deoxynucleoside analog (azaCdR). About 80% of the induced rearrangements were in chromosome 1, and almost 90% of these involved its pericentromeric region. Multibranched figures with up to seven chromosome 1 arms, as well as whole-arm deletions of this chromosome, were the predominant anomalies, often with one normal homolog of chromosome 1 present. Isochromosomes 1 and fusions in the pericentromeric regions of chromosomes 1 and 16 or chromosomes 1 and 9 were also seen. The overlap of the spectrum of chromosomal rearrangements in azaCR- or azaCdR-treated FLEB14 cells and in mitogen-stimulated lymphocytes from patients with a rare genetic disease (ICF) associated with localized DNA hypomethylation supports the hypothesis that the DNA demethylating activity of azaCR is essential for the induction of these pericentromeric rearrangements. These studies may help elucidate the overrepresentation of chromosome 1 pericentromeric rearrangements in many types of cancer cells.

Antimetabolites, Antineoplastic↗

PubMed1997

[Histologic evaluation of bone regeneration in cases of limb lengthening by Ilizarov's technique. An experimental study in the dog].

The histology of bone regeneration in cases of limb lengthening was studied in eight adult dogs. Following an osteotomy of the right fibula, an Orthofix (four dogs) or an Ilizarov external fixator (4 dogs) was installed and an osteotomy of the right tibia performed. Lengthening was started seven days after the surgery at the rate and rhythm of 0.5 mm every 12 hours for three weeks and was then followed by compression of 1 mm. The animals were then sacrificed in pairs 3, 6, 9 and 12 weeks after the start of lengthening. Histological evaluation of regenerate bone was performed using hematoxylin and eosin, trichrome and Von Kossa stain (decalcified). New bone at the site of distraction seemed to be formed mostly through intramembranous, and to a lesser extent, through endochondral ossification as evident by the presence of cartilaginous islands within the distraction gap of old specimens. However, these foci of cartilage cells did not have the appearance of growth plates. From the third week of lengthening, collagen fibers were laid down along the longitudinal axis of distraction. Mineralization of these fibers started at the bone ends and during the following weeks, progressed towards the center of the distraction gap. New bone was formed from both the medullary cavity and the periosteum.

Animals↗

PubMed1996

Operative management of aortic arch aneurysm using profound hypothermia and circulatory arrest.

Since the first successful replacement of the aortic arch with perfusion of the head, various methods have been employed to preserve cerebral function during aneurysm operations. Although deep hypothermia was used for surgery of the aortic arch, as early as 1963, the introduction of prolonged circulatory arrest has simplified replacements of the aortic arch. Between October 1990 and September 1993, 69 patients underwent aortic arch replacement for aneurysmal disease at the Dept. of Cardio-Thoracic Surg., University of Vienna. 52 patients had an acute dissection Type A, 17 patients were operated on electively. The patients age (48 male, 21 female) ranged between 16 and 81 years. Primary diagnosis was hypertension (n=44), marfan (n=14), unknown (n=10) and trauma (n=1). Total cardiopulmonary bypass was established via femoral artery cannulation. All patients received Cortison and Thiopental for added cerebral protection. Deep hypothermia (12 degrees C), confirmed by 0-EEG, and circulatory arrest were induced in all patients. The aneurysm was opened longitudinally and a full thickness single patch or "island" of aortic wall, containing the origins of the three arch vessels, was constructed and anastomosed in a continuous fashion to an albumin coated graft. 68 patients survived the operation (intraoperative mortality 1%). The 30-day mortality was 23% (n=16). Twelve patients died of multiorgan failure, two patients of a stroke and two due to myocardial infarction. The mean cerebral circulatory arrest time was 32 minutes (range 11-61 min.). Our experience with aortic arch replacements using profound hypothermia and circulatory arrest supports our contention, that it is the method of choice in this very difficult surgical field.

Adolescent↗

PubMed1995

A mutation in the 5' untranslated region of the human alpha-galactosidase A gene in high-activity variants inhibits specific protein binding.

Recently, normal individuals were identified who had high levels of plasma alpha-galactosidase A activity and a G to A transition in the 5' untranslated (5' UT) region of the alpha-galactosidase A gene. Electrophoretic mobility shift assays revealed that the wild-type sequence at the site of this mutation complexed with specific nuclear proteins. A standard NF-kappa B site competed with the 5' UT site for formation of these DNA-protein complexes. Complex formation was inhibited by the transition mutation. Therefore, the wild-type site might down-modulate expression of the alpha-galactosidase A gene from this 5' untranslated region, which includes a previously described protein-binding site for another family of sequence-specific DNA-binding proteins, methylated DNA-binding protein.

Base Sequence↗

PubMed1995

Increasing binding of a transcription factor immediately downstream of the cap site of a cytomegalovirus gene represses expression.

A closely related family of ubiquitous DNA binding proteins, called MDBP, binds with high affinity to two 14 base pair (bp) sites within the human cytomegalovirus immediate early gene 1 (CMV IE1) enhancer and with low affinity to one site beginning 5 bp downstream of the CMV IE1 transcription start point (+5 site). Unlike several cap position downstream MDBP sites in mammalian genes, these MDBP sites do not require cytosine methylation for optimal binding. Mutation of one of the enhancer MDBP sites to prevent MDBP recognition modestly increased the function of a neighboring CREB binding site in a transient transfection assay in the context of one promoter construct. A much larger effect on reporter gene expression (a 10-fold reduction) was seen when the low affinity MDBP recognition sequence at position +5 was converted to a high affinity site in a plasmid containing the CMV IE1 promoter upstream of the reporter gene. Evidence that the increased binding of MDBP at the mutant site is largely responsible for the observed results was provided by transfection experiments with this high affinity MDBP +5 site re-mutated to a non-binding site and by in vitro transcription assay.

Base Sequence↗

PubMed1995

Frequent detection of bcl-2/JH translocations in human blood and organ samples by a quantitative polymerase chain reaction assay.

Using an ultrasensitive assay involving the PCR, we have examined the frequency of a follicular lymphoma-associated translocation in peripheral blood from 132 individuals, most of whom were healthy blood donors. This translocation occurs between the bcl-2 proto-oncogene and the JH gene region and prolongs the life of lymphocytes. At a level of sensitivity of 1 translocation-bearing cell per 5 x 10(6) cells, almost one-half of healthy human adults had this translocation in the mononuclear fraction of peripheral blood. However, the range of frequency of these translocations spanned almost three orders of magnitude among translocation-positive individuals. Furthermore, there was a statistically significant increase with age in the percentage of individuals who were translocation positive. Such an age correlation was also seen for the percentage of blood donors with rather high translocation frequencies (> or = 20 per 5 x 10(6) peripheral blood mononuclear cells). However, the blood donor who had by far the highest concentration of this translocation was a healthy 35-year-old male containing approximately 900 apparently monoclonal, translocation-bearing cells per 5 x 10(6) peripheral blood mononuclear cells. Our findings suggest that some individuals who may be at risk for follicular lymphoma might be able to be identified by this PCR assay on peripheral blood. Also, these data may help explain the age dependence of the occurrence of this cancer.

Adolescent↗

PubMed1995

Reporter gene expression upon stable transfection when only a TATA box or a TATA box plus Sp1 sites are present 5' to the gene.

Episomal plasmids for stable transfection of mammalian cell cultures were constructed that have a G418-resistance (neo) gene immediately downstream of a highly truncated promoter. These plasmids had a function hygromycin-resistance gene (hyg) as a selectable marker. Surprisingly, in LTK- cells, but not HeLa cells, stably transfected with these BK virus-based plasmids having no promoter elements adjacent to the neo gene, readthrough transcription, probably from about 1 kb upstream, gave almost as efficient expression of the neo gene as of the hyg gene with a full-length promoter immediately upstream. When the transfecting plasmids contained Epstein-Barr virus (EBV) DNA sequences for episomal maintenance and had multiple Sp1 sites and a TATA box as the only promoter elements 5' to the neo gene, only about 3-9% of HeLa transfectants were G418 resistant (G418R). In transfections with analogous plasmids lacking these promoter elements 5' to the neo gene, no G418R colonies were seen. The establishment of the G418R phenotype probably required integration of plasmid DNA into favorable chromosomal sites and was aided by the presence of the TATA box plus Sp1 sites as a subminimal promoter. The absence of detectable G418-resistance in most of the HeLa transfectant clones obtained with EBV-type plasmids, even at a high plasmid copy number and even when a TATA box and six Sp1 sites were present immediately upstream of the neo gene, indicates that these elements do not suffice for appreciable gene expression in vivo and that this is a suitable model system for studying DNA rearrangements that can potentiate expression of the neo gene.

Animals↗

PubMed1995

Surgical treatment of type A aortic dissections. Results with profound hypothermia and circulatory arrest.

Type A aortic dissection still presents an emergency situation in cardiac surgery that is associated with high morbidity and mortality rates. There has been a significant improvement in the surgical outcome since the introduction of deep hypothermia and circulatory arrest. In this study, we discuss our results after operative repair of ascending aortic dissections, using deep hypothermia and circulatory arrest. This study presents the results of 67 patients (43 men, 24 women) from 18 through 81 years of age (mean, 54 years) who underwent surgery for type A dissecting aneurysm over a period of 4 years. Type A dissection (52 acute and 15 chronic cases) was due to Marfan syndrome in 12 patients, to atherosclerotic disease of the aorta in 27 patients, and to traumatic injury in 1 patient. Hypertension as the only pathologic finding was observed in 27 patients. Deep hypothermia (confirmed by isoelectric electroencephalogram) and circulatory arrest were induced in all patients. Two patients died intraoperatively due to massive bleeding (intraoperative mortality, 3%). The 30-day mortality rate was 30% (n = 20). Causes of perioperative deaths in order of frequency were multi-organ failure (n = 11), myocardial infarction (n = 2), postoperative bleeding (n = 2), cerebrovascular insult (n = 2), and sepsis (n = 1). The mean intensive care unit stay of the surviving 47 patients (72%) was 8 days, followed by a mean of 21 additional days in the hospital. Our experience with profound hypothermia and circulatory arrest, used in combination with coated grafts, supports our conviction that this is the method of choice for the treatment of type A dissecting aneurysm.

Adolescent↗

PubMed1995

[Surgery of thoracic and thoraco-abdominal aneurysms using deep hypothermia and cardiovascular arrest with continuous administration of blood cardioplegia].

Between January 1991 and February 1993, 14 patients (3 female, 11 male) aged between 21 and 79 years (mean 50 years) underwent reconstruction of the thoracic (n = 7) and thoracoabdominal aorta (n = 7). Four patients had previously undergone operation of the ascending aorta, in 3 patients coronary artery by pass grafting was performed before. All patients were operated using cardiopulmonary bypass with continuous blood cardioplegia, hypothermic circulatory arrest (11 degrees C nasopharyngeal temperature, 0-EEG) and posterolateral exposure. All patent lower intercostal and lumbar arteries (Th3-L5) were reimplanted. The 30-day mortality after repair of the thoracic aorta was 0, after replacement of the thoracoabdominal aorta 28.5% (n = 2). One patient died 70 days after replacement of the thoracic aorta as a consequence of a perioperative stroke. None of the surviving 11 patients developed a permanent neurologic deficit, renal or cardiac dysfunction. The average intensive care stay was 6 days for patients after replacement of the thoracic and 18 days for patients after replacement of the thoracoabdominal aorta. Our results indicate the method of elective hypothermia and circulatory arrest effective in spinal cord protection. The increase in the tolerable duration of spinal cord ischemia supports the reimplantation of all intercostal and lumbar vessels.

Adult↗

PubMed1995

Aortic valve resuspension in ascending aortic aneurysm repair with aortic insufficiency.

BACKGROUND: The known complications of prosthetic valve replacement in patients with an ascending aortic aneurysm and secondary aortic regurgitation who frequently have a morphologically normal aortic valve have prompted interest in valve-sparing aneurysm repair procedures. The aim of this study was to define the echocardiographic criteria for identifying suitable candidates for ascending aortic aneurysm repair that spares the aortic valve. We also examined the perioperative and intermediate-term results of this innovative procedure. METHODS: Fifteen patients underwent ascending aortic replacement with resuspension of the native valve within a vascular prosthesis and reimplantation of the coronary ostia. Echocardiography was performed preoperatively and intraoperatively, before discharge, and during follow-up. Thirteen patients had nondissecting aneurysms, and 2 patients had a Standford type A aortic dissection. The mean age of the patients was 48 +/- 18 years. Only patients with morphologically normal aortic leaflets and leaflets of similar size were selected. RESULTS: There was one death perioperatively, and this was due to sepsis. The procedure failed in 1 patient, and a valved conduit was implanted during the same operation. In the 13 others the aortic annulus diameter was significantly reduced from 27.1 +/- 2.2 mm preoperatively to 22.2 +/- 1.9 mm postoperatively (p < 0.05). The severity of aortic insufficiency decreased from 2.9 +/- 0.7 to 0.6 +/- 0.4 (p < 0.05). The peak aortic gradient increased from 11.5 +/- 6.5 to 20.3 +/- 16 mm Hg. A slight increase in the aortic annulus diameter to 24.3 +/- 1.0 mm and normalization of the peak aortic gradient to 9.8 +/- 7.8 mm Hg were noted at follow-up. There was no significant increase in aortic insufficiency. CONCLUSIONS: In selected patients undergoing ascending aortic aneurysm repair who have normal aortic leaflets but secondary aortic regurgitation, the native valve can be spared through this novel operation. The aortic annulus size is reduced significantly, thereby effectively eliminating hemodynamically significant aortic regurgitation. The intermediate-term results are promising, but the long-term durability of this type of repair needs to be determined.

Adult↗

PubMed1994

Binding of AP-1/CREB proteins and of MDBP to contiguous sites downstream of the human TGF-beta 1 gene.

Transcription of the human gene encoding transforming growth factor beta 1 (TGF-beta 1), which is a key regulator of cell growth and differentiation, is inducible by phorbol esters. DNA sequences resembling phorbol ester response elements (TREs) are present upstream and downstream of this gene. TREs are recognized by proteins from the AP-1 family of transcription factors. We examined a 16 basepair (bp) sequence downstream of the TGF-beta 1 gene that contains three putative TREs. This sequence had been shown to stimulate reporter gene expression from a downstream location in response to phorbol ester treatment. Electrophoretic mobility shift assays suggest that minor proteins from the related AP-1 and CREB families of transcription factors bind to the overlapping TREs within the 16 bp element. A site beginning at the end of this 16 bp element matches the consensus sequence of a DNA-binding protein called MDBP and was shown to bind to this protein. When the intact MDBP site was present in a reporter gene construct in addition to the TREs, the phorbol ester-induced stimulation of reporter gene expression was no longer observed. This suggests that MDBP can counteract the stimulation of transcription by AP-1/CREB-like proteins binding to this downstream enhancer element.

Base Sequence↗

PubMed1994

Sinus of Valsalva aneurysm: a late complication after repair of ascending aortic dissection.

Surgical advances and the introduction of new more rapid and accurate diagnostic techniques have led to significant improvement in the survival of patients with aortic aneurysms. However, considerable long-term morbidity and mortality remains a concern. In the present study we report on the occurrence of sinus of Valsalva (SV) aneurysm after repair of the ascending aorta for aortic dissection as a significant long-term complication. Since transesophageal echocardiography (TEE) became available it has been used for the follow-up of 33 hospital survivors after ascending aortic replacement for a mean of 27 +/- 20 months. Those patients who received a valved conduit were excluded from this analysis. The aortic valve was conserved in 22 patients: 17 had a dissecting aneurysm involving the ascending aorta and 4 patients non-dissecting aneurysms. A sinus of Valsalva diameter > 45 mm was considered an aneurysm and was found in a total of 7 patients (33%), 5 being patients with aortic dissection. The overall reoperation rate on account of SV aneurysms was 24%. We conclude that SV aneurysm is a significant long-term complication of patients after repair of the ascending aorta. In the light of these results we have changed our operative policy of repair to include resorcin glue as a reinforcing agent or to perform more extensive repair.

Aortic Dissection↗

PubMed1994

Effect of internal direct and inverted Alu repeat sequences on PCR.

We have studied the effect of repeated DNA sequence, especially Alu repeats, on PCR. Alu repeats are sequences that are approximately 300 bp long and interspersed at a very high copy number throughout the human genome. We amplified part of the human low-density lipoprotein receptor gene containing two Alu repeat sequences in the same orientation, approximately 7.8 kb apart, with unique sequence primers outside these repeats. The major PCR product was a DNA fragment with an in vitro deletion between the Alu repeats. The formation of this product depended on the template concentration and the type of polymerase used. Such a product arose apparently as a result of a "jumping reaction" involving a primer whose extension was terminated prematurely within one Alu repeated followed by annealing of such an incompletely extended primer to the other, distant Alu repeat. No such jumping products were seen when a 0.8-kb region containing two nearby inverted Alu repeats within the human alpha-galactosidase A gene was subject to PCR with unique sequence primers annealing just outside these repeats.

Animals↗

PubMed1994

Thoracoabdominal aneurysm repair: spinal cord protection using profound hypothermia and circulatory arrest.

Between January 1991 and February 1993, 14 patients (11 male, 3 female) between 21 and 79 years of age (median 50 years) underwent reconstruction of the thoracic (n = 7) and thoracoabdominal aorta (n = 7). Four patients had previously undergone operation of the ascending aorta, and in three patients coronary artery bypass grafting had previously been performed. All patients were operated on a via a posterolateral thoracotomy using cardiopulmonary bypass with continuous blood cardioplegia and hypothermic circulatory arrest (11 degrees C nasopharyngeal temperature, flat-EEG). All patent lower intercostal and lumbar arteries (T3 to L5) were reimplanted. The 30-day mortality after repair of the thoracic aorta was 0%; after replacement of the thoracoabdominal aorta, mortality was 28.5% (n = 2). One patient died 70 days after replacement of the thoracic aorta as a consequence of a perioperative stroke. None of the surviving 11 patients developed a permanent neurological deficit or renal or cardiac dysfunction. The average intensive care stay was 6 days for patients after replacement of the thoracic aorta and 18 days for patients after replacement of the thoracoabdominal aorta. Our results suggest that use of elective hypothermia and circulatory arrest for spinal cord protection is highly effective. We, therefore, recommend this method for complex reconstructions of the thoracoabdominal aorta.

Adult↗

PubMed1994

Expression of mRNAs encoding ARPP-16/19, ARPP-21, and DARPP-32 in human brain tissue.

In this study we have isolated and sequenced human cDNAs for the phosphoproteins DARPP-32, ARPP-21, and ARPP-16/19, and have compared these sequences to previously characterized bovine and rat cDNAs. In situ hybridization and Northern blot analysis with the human cDNA probes were used to study the expression of mRNAs encoding ARPP-16/19, ARPP-21, and DARPP-32 in human postmortem brain tissue. In situ hybridization was performed using horizontal whole hemisphere sections. Five representative levels of the brain ranging from 71 mm to 104 mm ventral to vertex were examined. All three probes showed distinct hybridization patterns in the caudate nucleus, putamen, nucleus accumbens, and the amygdaloid complex. For ARPP-16/19 mRNA, a hybridization signal comparable to the signal in caudate nucleus, putamen, and nucleus accumbens was also detected in the neocortex. ARPP-21 and DARPP-32 mRNA, on the other hand, were present in lower levels in neocortical regions. DARPP-32 mRNA was abundant in the cerebellar cortex at the level of the Purkinje cell layer. High levels of ARPP-16/19 and ARPP-21 mRNA were also found in the cerebellar cortex, where they were confined to deeper layers. The present result demonstrate that mRNAs for the three phosphoproteins are expressed in overlapping, but also distinct, areas of the human brain that in many cases coincide with previously described distribution of the dopamine D1 receptor.

Aged↗

PubMed1994

Detection and quantitation of low numbers of chromosomes containing bcl-2 oncogene translocations using semi-nested PCR.

A PCR assay has been optimized for the detection of one or a few molecules of a translocation-containing human DNA sequence in the presence of a vast excess (7 micrograms) of the normal human genome. This procedure avoids blot hybridization by the use of two rounds of PCR with 20-22 cycles of amplification per round and by the replacement of one of the two primers from the first round of PCR with a different primer in the second round (semi-nested PCR). We demonstrate that very low numbers of the target DNA molecules can be quantitated by this semi-nested PCR. This method can be used to detect a single DNA molecule from one mutant cell displaying a translocation between the bcl-2 proto-oncogene region and a JH immunoglobulin gene sequence [t(14;18)] in a background of normal human DNA from 10(6) cells.

Base Sequence↗

PubMed1993

The expression of a novel receptor-type tyrosine phosphatase suggests a role in morphogenesis and plasticity of the nervous system.

Analysis of the localization of receptor-type protein tyrosine phosphatase-beta (RPTP-beta) by in situ hybridization and immunocytochemistry indicates that it is predominantly expressed in the developing central nervous system (CNS). RPTP-beta is highly expressed in radial glia and other forms of glial cells that play an important role during development. The immunoreactivity localizes to the radial processes of these cells, which act as guides during neuronal migration and axonal elongation. The pattern of RPTP-beta expression changes with the progression of glial cell differentiation. In the adult, high levels of RPTP-beta are seen in regions of the brain where there is continued neurogenesis and neurite outgrowth. The spatial and temporal patterns of RPTP-beta expression suggest that this receptor phosphatase plays a role in morphogenesis and plasticity of the nervous system.

Animals↗