Biomedical subjects

M Hummel

Publications and source records attributed to M Hummel.

At least 253 records · Page 14Linked to original sources

PubMed1992

[Heterogeneous Epstein-Barr virus infection patterns in peripheral T cell lymphoma of the angioimmunoblastic lymphadenopathy type].

32 cases of T cell lymphoma of angioimmunoblastic lymphadenopathy type (AILD-TCL) were investigated for their association with Epstein-Barr virus (EBV). Polymerase chain reaction (PCR) for detection of EBV-DNA and in situ hybridization for EBV-encoded small nuclear RNAs (EBER) produced almost identical results, showing that all but one of AILD-TCL cases contained EBV genomes. Three distinctive patterns of EBV infection were observed after immunophenotypical characterization of EBER positive cells: 1. predominant infection of B-immunoblasts (26% of the cases), 2. predominant infection of neoplastic T cells (42% of the cases) and 3. infection of few small lymphocytes (32% of the cases). EBV-encoded latent membrane protein was frequently detectable in cases exhibiting patterns 1 and 2. These findings suggest that, in AILD-TCL patients B cells and especially T cells are highly susceptible to a persistent EBV infection which may lead to a growth advantage of infected cells.

DNA, Viral↗

PubMed1992

[Epstein-Barr virus associated lymphocyte proliferation].

In recent years, techniques, probes, and reagents became available to reliably visualize individual Epstein-Barr virus (EBV)-infected cells, to assess EBV gene expression, and to analyze the clonal composition of EBV genomes in human tissues. Application of these techniques to more than 1000 lymphoid tissue specimens revealed (1) characteristic cellular and compartmental distribution patterns of EBV-infected cells in normal lymph nodes, reflecting the interference of EBV with physiologic B cell differentiation pathways, (2) an association of EBV with various mono- and oligoclonal lymphoproliferations ranging from benign conditions to overtly malignant lymphomas, and (3) characteristic patterns of EBV gene expression among EBV-associated lymphoproliferations. In the context of the established immortalizing and transforming properties of EBV, the findings support the concept of an etiologic role of EBV for cases of certain lymphomas such as Burkitt's lymphoma, anaplastic large cell lymphoma, Hodgkin's disease, and lymphomas arising in immunocompromised individuals. In contrast, lymphomas harboring EBV in only proportions of the tumor cells (such as cases of peripheral T cell lymphoma and some B cell lymphoma types) argue against an etiologic role in the primary process of malignant transformation for the virus in these instances. Since in many of these cases a proportion of the EBV infected tumor cells express the EBV oncoprotein LMP (latent membrane protein) the virus may influence, however, the proliferative properties as well as the morphological and molecular phenotype of the neoplastic cells.

B-Lymphocytes↗

PubMed1992

[Heart transplantation--indications and results].

Heart transplantation has become a standard procedure in the treatment for irreversible heart failure. Criteria for both recipients and donors have been extended. One year survival now reaches 81%. In the immediate postoperative course patients are endangered by infection. In the long-term course coronary artery disease of the transplanted heart becomes the most serious problem. Alteration of liver and kidney function due to chronic medication as well as malignancies and hypertension also occur. In case of chronic transplant failure retransplantation may be indicated. Acute cardiac failure before transplantation nowerdays can be treated by mechanical circulatory assist devices.

Follow-Up Studies↗

PubMed1992

[Progress in heart transplantation].

Within the past 10 years, heart transplantation has become established as a standard procedure in heart surgery. Improvements in immunosuppressive therapy and diagnosis of graft rejection have been crucial. The criteria for transplantation have been broadened for recipients as well as for donors. Newborns, pediatric patients, diabetics, and patients with impaired renal function will no longer be excluded from transplantation due to improved postoperative therapy. Furthermore, progress has been made with assisted circulation. Patients with acute heart failure can now be bridged to transplantation.

Adult↗

PubMed1992

[Therapeutic control of premedication with famotidine given on the evening before surgery for the prevention of pneumonitis in heart surgery patients].

Pulmonary damage after aspiration of acid gastric content is one of the major risks of general anaesthesia. Antisecretory therapy with different H2-antagonists can effectively decrease the risk of aspiration. The effective dosage and the method and timing of administration remain unclear. PATIENTS AND METHODS. A series of 38 patients scheduled for elective cardiac surgery (coronary artery bypass graft) were premedicated at random at 10:00 p.m. on the evening prior to surgery with famotidine 40 mg and flunitrazepam 0.5 mg p.o. or with flunitrazepam alone. Continuous intragastric pH monitoring (720 values/h) with a combined glass electrode was started immediately after induction and continued for at least 12 h after surgery, in most cases up to extubation. The time periods analyzed were the first 30 min after induction, time of surgery, 12 h after surgery, and time of extubation. For each period the number of pH values less than 2.5 and pH less than 4, mean and median, and significance of differences were calculated. STATISTICS. Test statistics were evaluated using the Wilcoxon test and the Mann-Whitney U-test. RESULTS. (see Table 1, Fig. 1). The mean time interval between oral premedication and induction of anaesthesia was 9.7 h. There were no differences between the groups concerning age and duration of surgery. The average age was 51 in the group of treated patients (n = 15) and 59 years in the control group (n = 23). The average duration of surgery was 3.36 h and 4.02 h. During induction and in the following 30 min, in the famotidine treatment group 28.7% of all pH values were pH less than 2.5, as against 45.4% in the control group (P = 0.08). Intraoperative values: 16.3% pH less than 2.5 against 24.7% (not significant); 12 h postoperative: 21.1% vs 17.8% and during extubation 40% vs 21% (not significant). During induction there were more pH values less than 2.5 in the control than in the treatment group (P = 0.08). Treated patients had nearly 30% pH values less than 2.5 and therefore, a persisting risk of acid aspiration. In both groups intragastric acidity decreased during surgery. Postoperatively there was no difference between the two groups, and during extubation more patients in the famotidine-treated group had values below pH 2.5. CONCLUSION. Prophylaxis of acid aspiration before, during and after cardiac surgery can be achieved by increasing the pH of the gastric content. The timing and the method of administration must be selected to a safe decrease in intragastric acidity before the induction of general anaesthesia. Famotidine 40 mg given orally at 10.00 p.m. on the evening before surgery is not a reliable means of decreasing intragastric acidity or, consequently, of preventing of acid aspiration syndrome.

Administration, Oral↗

PubMed1991

Epstein-Barr virus DNA and latent gene products in Ki-1 (CD30)-positive anaplastic large cell lymphomas.

Epstein-Barr virus (EBV)-specific DNA sequences were detected by polymerase chain reaction analysis in 15 of 47 (32%) DNA extracts prepared from CD30-positive (Ki-1 antigen-positive) anaplastic large cell (ALC) lymphomas. EBV-encoded RNA (EBER) transcripts could be detected by in situ hybridization in the tumor cells of 9 of 11 EBV DNA-positive cases. Twenty-eight cases were examined by immunohistology on cryostat sections for the presence of the EBV-encoded latent membrane protein (LMP), the nuclear antigen 2 (EBNA2), the BZLF1 transactivator protein, and the late viral glycoprotein gp350/250. A distinct LMP-specific membrane and cytoplasmic staining was detected exclusively in lymphoma cells of five cases (18%); two of these cases additionally expressed EBNA2. BZLF1 protein and gp350/250 immunoreactivity was absent in all instances. All LMP-positive cases contained EBV DNA and EBER sequences. The pattern of EBV latent protein expression in ALC lymphomas showed heterogeneity with respect to EBNA2 expression: LMP-positive/EBNA2-negative cases displayed a pattern previously described for undifferentiated nasopharyngeal carcinomas and Hodgkin's disease, whereas LMP-positive and EBNA2-positive cases showed parallels to lymphoblastoid cell lines. Because the LMP gene has transforming potential, our findings support the concept of a pathoetiologic role for EBV in a proportion of CD30-positive ALC lymphomas.

Adult↗

PubMed1991

Undulin is a novel member of the fibronectin-tenascin family of extracellular matrix glycoproteins.

We characterized cDNA clones specific for the extracellular matrix glycoprotein undulin. Two sets of cDNA clones were isolated from a human placental lambda gt11 expression library and from a rhabdomyosarcoma cell line encoding two partially identical carboxyl-terminal polypeptides of 843 (Un1) and 443 (Un2) amino acids suggesting differential splicing of a single gene transcript. Northern blot analysis of human rhabdomyosarcoma cell poly (A) RNA with cDNA specific for Un1 identified transcripts of approximately 4.2, 6.5, and 8.5 kilobases, whereas a probe specific for Un2 detected a single mRNA of approximately 5 kilobases. Since a monoclonal antibody that is reactive with a sequence encoded by Un1 and not by Un2 detects the bands considered characteristic for undulin in Western blots, the mRNAs related to Un1 may code for the major part of the undulin molecule. The protein sequences deduced from Un1 and Un2 reveal an amino-terminal differentially spliced von Willebrand factor A domain, characteristic of proteins that interact with interstitial collagens, which is linked to fibronectin-like type III homology units by a unique sequence of 57 amino acids. Whereas Un2 encodes two complete and one incomplete type III homologies followed by a unique acidic carboxyl-terminal domain of 118 amino acids, Un1 codes for seven complete and one truncated type III homologies, followed by a short proline-rich carboxyl-terminal segment of 23 amino acids. Considering the 298 amino acids occurring in identical segments, the 989 different amino acid positions deduced from clones Un1 and Un2 represent an estimated 40% of the overall undulin sequence. In the context of 1) rotary shadowing electron microscopy data showing undulin as a structure composed of nodules that are interconnected by flexible rods of varying size, 2) the presence of three major bands of Mr 270,000, 190,000, and 180,000 in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with 3) common antigenic epitopes and similar peptide maps (Schuppan, D., Cantaluppi, M.C., Becker, J., Veit, A., Bunte, T., Troyer, D., Schuppan, F., Schmid, M., Ackermann, R., and Hahn, E.G. (1990) J. Biol. Chem. 265, 8823-8832), our finding of differentially spliced type III homology units, as found in tenascin and fibronectin, suggests that undulin is another member of the fibronectin-tenascin family of extracellular matrix glycoproteins. Furthermore, as in fibronectin and tenascin, undulin bears an additional subset of interactive domains tailored to specific structural and functional roles in development and differentiation.

Amino Acid Sequence↗

PubMed1991

[Therapy of terminal heart failure using heart transplantation].

Heart transplantation (HTx) has now become an accepted treatment modality for end-stage heart disease. The limited supply of suitable donor organs imposes constraints upon the decision of who should be selected for transplantation. Usually patients are candidates for HTx, who remain NYHA functional class III or IV despite maximal medical therapy. Further criteria are low left ventricular ejection fraction (less than 20%) with heart rhythm disturbances class IIIA-V (LOWN), which are associated with poor prognosis. Additionally, the suffering of the patient and also the course of heart failure are essential for judging the urgency of HTx. Contraindications are absolute in patients with untreated infections, fixed pulmonary vascular resistance (PVR) above 8 WOOD-degrees, severe irreversible kidney and liver disease, active ventricular or duodenal ulcers and acute, psychiatric illness. HTx is relatively contraindicated in patients with diabetes mellitus, age over 60 years, PVR above 6 WOOD-degrees and an unstable psychosocial situation. To prevent rejection of the transplant heart, live-long immunosuppressive therapy is needed. Most immunosuppressive regimes consist of Cyclosporine A and Azathioprine (double drug therapy) or in combination (tripple drug therapy) with Prednisolone. For monitoring of this therapy, control of hole blood cyclosporine A level and white blood count is needed. Rejection episodes can be suspected if there is a greater than 20 mmHg decrease of systolic blood pressure, elevated body temperature, malaise, tachycardia or heart rhythm disturbance. The diagnosis of cardiac rejection can be established by endomyocardial biopsy. Measurement of the voltage of either the surface or intramyocardial ECG, echocardiography with special consideration to early left ventricular filling time as well as immunological methods are additionally used tools. Graft sclerosis as the main risk factor of the late transplant period remains an unsolved problem.

Adaptation, Psychological↗

PubMed1991

Epstein-Barr virus latent membrane protein expression in Hodgkin and Reed-Sternberg cells.

Cryostat sections from lymph nodes of 47 Hodgkin disease patients were examined by immunohistology for the Epstein-Barr virus (EBV)-encoded latent membrane protein (LMP), nuclear antigen 2, and late viral glycoprotein gp350/250. A distinct LMP-specific membrane and cytoplasmic staining was detected exclusively in Hodgkin and Reed-Sternberg cells in 18 patients (38%); EBV nuclear antigen 2 and gp350/250 immunoreactivity was absent in all instances. Thirty-two of 47 (68%) cases contained EBV-specific DNA sequences as detected by PCR, all LMP-positive cases being in this category. Our results confirm previous studies establishing the presence of EBV genomes in Hodgkin and Reed-Sternberg cells by demonstrating expression of an EBV-encoded protein in the tumor-cell population. The finding of LMP expression in the absence of EBV nuclear antigen 2 suggests a pattern of EBV gene expression different from that of B-lymphoblastoid cell lines and Burkitt lymphoma, whereas this finding shows similarities with that seen in undifferentiated nasopharyngeal carcinoma. Because the LMP gene has transforming potential, our findings support the concept of a pathoetiological role of EBV in many cases of Hodgkin disease.

Adult↗

PubMed1991

[Risk of adrenal cortex insufficiency following heart transplantation].

In 20 patients we studied the function of the corticotropic pituitary and adrenal gland 13 to 45 month (m = 27.1) after heart transplantation (HTx). For prophylactic immunosuppression all patients were treated with triple drug therapy, including Cyclosporine A, Azathioprine and Prednisolone. After performing the CRH-test we could demonstrate, that in all patients, treated with Prednisolone (0.09-0.15 mg/kg/day) for more than 1 year, adrenal insufficiency was evident. Patients must be controlled carefully, if therapy with steroids is stopped thereafter, not only because of increased risk of rejection but also because metabolic disturbance caused by adrenal insufficiency may occur. In case of elevated demand of steroids (i.e. infections or surgery), adequate substitution with glucocorticosteroids is needed.

Adrenal Cortex Function Tests↗

PubMed1991

Mechanical left ventricular support as a bridge to cardiac transplantation in childhood.

The mechanical extrathoracic "Berlin Heart" cardiac assist device was used for left ventricular support in an 8-year-old child of 27 kg body weight. Terminal left ventricular failure and life-threatening ventricular tachyarrhythmias in this child were sequelae of coarctation of the aorta, aortic stenosis and resultant severe left ventricular dilatation, hypokinesia and fibrosis. With the assist device, cardiogenic shock could be reversed. The child was extubated and mobilized during an 8-day waiting period for orthotopic heart transplantation. This case illustrates that the use of ventricular assist devices can be successfully extended to children and may be advantageous compared to other techniques of mechanical circulatory support, such as balloon pumping or extracorporeal membrane oxygenation.

Age Factors↗

PubMed1991

[Expression of latent membrane proteins (LMP) of Epstein-Barr virus in malignant lymphomas].

The presence of Epstein-Barr virus (EBV) DNA and antigens was assessed by polymerase chain reaction and immunohistology, respectively, in a total of 92 cases of Hodgkin's disease, angioimmunoblastic lymphadenopathy, CD30-positive anaplastic large cell (ALC) lymphomas, and AIDS-associated atypical lymphoproliferations (ALP). Proportions of the EBV DNA-positive lesions showed latent membrane protein (LMP) expression; some of the LMP-positive ALC lymphomas and ALP cases also displayed EBNA2 immunostaining. BZLF1-protein and gp250/350 immunoreactivity were absent in all instances indicating latent EBV infection. Since the LMP gene has transforming potential, our findings support the concept of a pathoetiological role for EBV in these lymphoproliferative lesions.

Acquired Immunodeficiency Syndrome↗

PubMed1990

Familial hypercholesterolemia in a rhesus monkey pedigree: molecular basis of low density lipoprotein receptor deficiency.

We have recently identified a family of rhesus monkeys with members exhibiting a spontaneous hypercholesterolemia associated with a low density lipoprotein receptor (LDLR) deficiency. By using the polymerase chain reaction, we now show that the affected monkeys are heterozygous for a nonsense mutation in exon 6 of the LDLR gene. This mutation changes the sequence of the codon for amino acid 284 (tryptophan) from TGG to TAG, thereby generating a nonsense codon potentially resulting in a truncated 283-amino acid protein, which needs documentation, however. This G----A mutation also creates a site for the restriction endonuclease Spe I. Using this site as a marker for this nonsense mutation, we have shown that the mutation is present in all of the affected members of the pedigree and absent in unaffected members and that the mutation segregates with the phenotype of spontaneous hypercholesterolemia through three generations. Quantitative analyses of RNA obtained from liver biopsies show that the abundance of the LDLR RNA is also reduced by about 50%. Thus, we have identified a primate model for human familial hypercholesterolemia which will be useful for studying the relationship between the LDLR and lipoprotein metabolism and for assessing the efficacy of diets and drugs in the treatment of human familial hypercholesterolemia.

Animals↗

PubMed1990

[Epstein-Barr virus and malignant lymphomas--studies on incidence and localization of viral DNA].

Tissue specimens from 198 cases of Hodgkin's disease and 151 non-Hodgkin lymphomas as well as 34 non-malignant lymph node biopsies were examined for the presence of Epstein-Barr virus (EBV) DNA by polymerase chain reaction. EBV-specific DNA sequences were detected in DNA extracts of 58% of Hodgkin's disease biopsies. Non-Hodgkin lymphomas and benign lymph node lesions were associated with EBV in far smaller proportions. In Hodgkin's disease biopsies, subsequent in situ hybridization revealed an exclusive localization of EBV DNA in the tumour cells, suggesting an involvement of EBV in the pathogenesis of Hodgkin's disease in a substantial proportion of cases.

Base Sequence↗

PubMed1990

High incidence of Epstein-Barr virus genomes in Hodgkin's disease.

Tissue specimens from 198 cases of Hodgkin's disease and 151 non-Hodgkin lymphomas, as well as 34 nonmalignant lymph node biopsies were examined for the presence of Epstein-Barr virus (EBV) DNA by polymerase chain reaction. Epstein-Barr virus-specific DNA sequences were detected in DNA extracts from frozen and/or paraffin-embedded tissues of 58% of Hodgkin's disease cases. High and low grade non-Hodgkin lymphomas as well as chronic lymphocytic leukemia biopsies contained EBV DNA in 26%, 14%, and 7% of the cases, respectively. Ten percent of the control lymph nodes with normal histology were EBV positive. In Hodgkin's disease biopsies, subsequent in situ hybridization revealed an exclusive localization of the viral DNA in the tumor cells. These findings suggest an involvement of EBV in the pathogenesis of Hodgkin's disease in a substantial proportion of cases.

Base Sequence↗

PubMed1990

Detection of HTLV-I proviral sequences in CD30-positive large cell cutaneous T-cell lymphomas.

To investigate the possibility that cutaneous T-cell lymphomas of large cell type may be associated with human T-cell leukemia/lymphoma virus type I infection in nonendemic regions, tissue samples from six cases of large cell cutaneous T-cell lymphoma and four cases of small cell cutaneous T-cell lymphoma were screened for the presence of integrated proviral human T-cell leukemia/lymphoma virus type I DNA. Combined use of Southern blot hybridization and enzymatic DNA amplification revealed human T-cell leukemia/lymphoma virus type I-specific sequences in all cases of large cell cutaneous T-cell lymphoma and in none of the cases of small cell cutaneous T-cell lymphoma. These results suggest that in nonendemic areas, a significant proportion of large cell cutaneous T-cell lymphoma cases are associated with human T-cell leukemia/lymphoma virus type I.

Adolescent↗

PubMed1989

Gene synthesis, expression in Escherichia coli and purification of immunoreactive human insulin-like growth factors I and II. Application of a modified HPLC separation technique for hydrophobic proteins.

We have expressed synthetic genes encoding human insulin-like growth factors I and II in large quantities in Escherichia coli as fusion proteins with the 300 N-terminal amino acids of the E. coli trpE gene product. The resulting hybrid proteins were purified from the insoluble fraction of crude bacterial lysates using a rapid HPLC separation procedure employing a C8 reversed-phase column and a gradient of 2-propanol in formic acid. With the procedure we obtained in volatile solvents highly purified fusion proteins that were used for further biochemical and immunological procedures. Here we describe biochemical characteristics of the bacterially expressed fusion proteins and demonstrate that these proteins share substantial antigenic properties with the native polypeptides allowing the establishment of highly specific monoclonal antibodies.

Amino Acid Sequence↗

PubMed1989

Long-acting somatostatin analog controls acid and gastrin secretion in benign, not in malignant, Zollinger-Ellison syndrome.

The long-acting somatostatin (SMS) analog, SMS 201-995 has beneficial effects on APUDomas. In two Zollinger-Ellison syndrome (ZES) patients we assessed basal acid output (BAO) and 24-h pH under SMS and compared them to controls. We also assessed total gastrin, gastrin 17, insulin, glucagon, C-peptide, and SMS by radioimmunoassay. In the benign gastrinoma, an acid-controlling action of SMS was shown, elevating the 24-h pH threshold over the pH range 1.5-5 of 55-10% compared with control. A parallel inhibition of the gastrins greater than 90% was apparent. We found no beneficial effect on gastric acid secretion and on tumor gastrin in the malignant gastrinoma despite a fourfold higher plasma SMS level. Non-tumor-related peptides were suppressed by approximately 50% and in contrast to gastrin they again reached pre-SMS levels before the next dose of the drug. We conclude that SMS is more effective in benign than in malignant gastrinomas, and may be exclusively so.

Female↗