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Biomedical subjects

W Dietrich

Publications and source records attributed to W Dietrich.

104 records · Page 6Linked to original sources
PubMed1985

Terminal repetitive sequences in herpesvirus saimiri virion DNA.

The H-DNA repeat unit of Herpesvirus saimiri strain 11 was cloned in plasmid vector pAGO, and the nucleotide sequence was determined by the dideoxy chain termination method. One unit of repetitive DNA has 1,444 base pairs with 70.8% G+C content. The structural features of repeat DNA sequences at the termini of intact virion M-DNA (160 kilobases) and orientation of reiterated DNA were analyzed by radioactive end labeling of M-DNA, followed by cleavage of the end fragments with restriction endonucleases. The termini appeared to be blunt ended with a 5'-phosphate group, probably generated during encapsidation by cleavage in the immediate vicinity of the single ApaI recognition site in the H-DNA repeat unit. The sequence did not reveal sizeable open reading frames, the longest hypothetical peptide from H-DNA being 85 amino acids. There was no evidence for an mRNA promoter or terminator element, and H-DNA-specific transcription could not be found in productively infected cells.

Animals↗
PubMed1985

[Anesthesiologic treatment of 3,665 patients in Red Cross hospitals in Thailand, Lebanon, Pakistan and Indonesia].

Between the end of 1979 and the beginning of 1984, the authors served as anaesthetists for Red Cross missions in surgical field hospitals on the Thai-Cambodian and the Afghan-Pakistan borders, in Lebanon, and in Indonesia. A total of 3665 civilian emergency patients were anaesthetised. 643 were operated on under local anaesthesia; 639, under regional anaesthesia, in most cases spinal anaesthesia. In spite of principal preference for local and regional anaesthetic techniques, 65% of the patients (2383 patients) were managed under general anaesthesia, which was maintained with halothane in 947 cases and ketamine in 1345 cases. 877 general anaesthesias with ketamine were performed with spontaneous breathing of ambient air; endotracheal anaesthesia was necessary in 1238 patients. In spite of the high risk for the patients and of the operative interventions and in the light of the simple and sometimes even primitive working conditions, no anaesthesia-related fatalities occurred. Postoperative lethality was 2%. In all cases, the duties of the anaesthesist involved more than performance of anaesthesia, which was sometimes assigned to paramedics. Other duties included preoperative examination, postoperative intensive care, consultation services in nonsurgical emergency cases, resuscitation, and training of local assistants.

Anesthesia↗
PubMed1984

Residual ethylene oxide in hollow-fiber dialyzers.

The deaeration and extraction kinetics of ethylene oxide (ETO) in hollow-fiber dialyzers were examined. The investigations showed that both deaeration and extraction can be described by two additive first-order kinetic expressions. The ETO content of membranes decreased rapidly at first, followed by a second slower decrease. Even after prolonged storage time, residual ETO was still detectable in the milligram range. These residuals cannot be eliminated by the usual rinsing of the dialyzer prior to use.

Ethylene Oxide↗
PubMed1984

[Antithrombin III substitution for optimization of the heparin effect during extracorporeal circulation in heart surgery].

In a prospective randomised study 20 patients undergoing coronary bypass surgery were assigned to two groups. Patients in group I (n = 10) received initially 250 IU heparin X kg-1 before the start of extracorporeal circulation. Patients in group II (n = 10) were given the same amount of heparin and in addition 1 000 units of purified human antithrombin III (AT III) concentrate. A highly significant lower heparin coefficient [2.69 +/- 0.57 IU X kg-1 X min-1, which is a parameter of heparin consumption (units of heparin X kg-1 given per minute during the time of heparinisation)], was found in group II compared to group I (3.73 +/- 0.56 IU X kg-1 min-1). Heparin sensitivity, measured as an increase in the ratio of activated coagulation time (ACT) X IU heparin-1 X kg-1 as a response to initial heparin dose, was found to be significantly higher (1.22 +/- 0.30 sec X IU heparin-1 X kg-1) in patients receiving AT III as measured in the control group (0.95 +/- 0.23 s X IU heparin-1 X kg-1). Mean values of ACT during the period of heparinisation were comparable (group I: 533 +/- 81 s, group II: 512 +/- 62 s) in the two groups. The substitution of AT III led to an increase of plasma AT III activity of 1.4% per substituted unit AT III X kg-1. AT III plasma activity, corrected to initial haematocrit levels to avoid dilution dependency, decreased as a consequence of extracorporeal circulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Antithrombin III↗
PubMed1984

[Estradiol receptors in the cytosol of nitrosomethylurea-induced mammary tumors of the rat. Influence of cell nuclei on the cytoplasmic estradiol receptor].

The cytoplasmic estradiol receptor (ERc) in N-nitrosomethylurea induced mammary tumors of the rat was described and its binding properties were characterized. We found an estradiol receptor incidence of 100% and an ERc content of 40 +/- 10 fmol/mg cytosol protein (n = 18) 3-4 days after ovariectomy. A dissociation constant (KD) of 2,2 +/- 1,1 X 10(-10) M was measured. The optimal incubation time for the determination of the ERc was found to be c.18 h (0-4 degrees C). The occupied ERc was relatively stable (we observed only a c. 20% degradation of the estradiol receptor after an incubation time of 66 h (0-4 degrees C) in comparison with the value found during an incubation time of 18 h (0-4 degrees C), the unoccupied ERC is more instable. We found an inactivation of ERc after freezing of tumor tissue in dry ice for longer times (in this paper for 18 d). The occupied estradiol receptor was stable for at least 30 min at 30 degrees C, if an excess of steroid is available in the assay system (in this paper 4 X 10(-9) M). A distinct degradation was observed if occupied cytosol was incubated at 37 degrees C. We found a fast inactivation of the ERc if cytosol and nuclei were incubated together at 30 degrees C. At temperatures of 0-4 degrees C (incubation of cytosol plus nuclei) a slight degradation of the ERc could be seen. This degradation was not significant in every case. Nuclei of N-nitrosomethylurea-induced mammary tumors of the rat possess apparently a "factor" which is able to inactivate the cytoplasmic estradiol receptor and is highly active at elevated temperatures. It is possible that this "factor" also acts at temperatures of 0-4 degrees C but with diminished activity.

Animals↗
PubMed1983

Cloning of Herpesvirus saimiri DNA fragments representing the entire L-region of the genome.

Purified particles of Herpesvirus saimiri, a potent tumor-eliciting virus of primates, contain genomic DNA molecules (145-170 kb) consisting of a unique L-DNA region (112 kb) which is flanked by variable stretches of repetitive sequences (H-DNA). Restriction fragments representing the entire L-DNA of H. saimiri strain No. 11 were cloned in plasmid and bacteriophage vectors. The internal fragments of L-DNA generated by the enzymes EcoRI and KpnI were inserted into plasmid pACYC184, cosmid pJC81, or bacteriophage lambda derivative Charon 4A. The terminal parts of L-DNA, including the junctions between repetitive DNA and unique sequences, were cloned between the cleavage sites for KpnI and SmaI in the plasmid vector pWD7, which was constructed for this purpose. Molecular cloning allowed us to confirm and modify, in part, the existing cleavage maps of H. saimiri DNA. It provides a basis for future studies on virus replication and oncogenic transformation.

Bacteriophage lambda↗
PubMed1983

Virus-specific transcription in a Herpesvirus saimiri-transformed lymphoid tumor cell line.

Herpesvirus saimiri-transformed lymphoid tumor cell lines contain nonintegrated covalently closed circular viral DNA molecules in high multiplicity. One of those cell lines, 1670, carries large viral DNA circles (202 kilobase pairs) with two stretches of repetitive DNA (70.8% G + C) that are interspersed between two segments of unique DNA (36% G + C). Since it was not known if there is any viral gene expression in H. saimiri-transformed cells, we initiated a study of transcription in cell line 1670. cDNA was generated by reverse transcription of cellular RNA and hybridized with cloned virion DNA fragments. The experiments indicated that appreciable transcription is restricted to a single segment of unique DNA. This sequence is present once only in the circular viral DNA and corresponds to unique DNA between map units 0.89 and 0.93 of virion DNA. By Northern blot hybridizations with labeled cloned probes of virion unique DNA, one predominant virus-specific polyadenylated transcript of, at most, 2.7 kilo-bases could be detected in tumor cell line 1670. The direction of transcription was determined by hybridization with randomly primed cDNA and, in parallel, with oligodeoxythymidylate-primed cDNA probes. Apparently, the patterns of virus-specific RNA synthesis in the H. saimiri-transformed cells are clearly distinct from the transcription program in other herpesvirus transformation systems analyzed before.

Animals↗
PubMed1983

[Reduction of whole blood requirements in coronary surgery with hemoseparation and isovolemic hemodilution].

Because of relative shortage of homologous stored blood, and the dangers of transmission infectious diseases and isoimmunisation, we tried to reduce blood requirement in cardiac surgery. In 139 patients undergoing coronary artery bypass surgery different techniques of autotransfusion were applied. A 52% reduction of whole blood transfusion compared to a control group of patients could be obtained by preoperative isovolaemic haemodilution. The application of haemoseparation reduced the amount of whole blood used by 55%. When the two techniques were combined the use of whole blood was reduced by 70% compared to the control group of patients. In contrast retransfusion of blood remaining in the oxygenator is not advisable because only a small amount of blood can be saved in this way and in addition it results in a higher risk of postoperative bleeding. Our results will be discussed reviewing the literature.

Blood Transfusion↗
PubMed1982

[Incidence and importance of nuclear estradiol receptors in human breast cancer].

A literature study about the incidence of estradiol receptors in nuclear fractions of human mammary carcinomas and the importance of these receptors for the endocrine therapy were done. Because it is very difficult to isolate purified nuclei from human mammary tumor tissue most of the authors use a crude nuclear fraction (repeated washed 800 g pellet) for the receptor studies. A contamination of the nuclear receptor by receptor proteins of other fractions of the target cell is possible. Occupied (ERn+) and unoccupied (Rn+) nuclear estradiol receptors are demonstrable in more than 50% of tumor tissues with positive cytoplasmic estradiol receptors (ERc+). Both nuclear receptors were often found side by side. Mammary tumor tissues without cytoplasmic estradiol receptor have got seldom nuclear receptors. The response of endocrine therapy, the prognosis and the survival are more favourable in patients with ERc+, Rn+ than in patients with ERc+, Rn-. Regressions after hormone therapy are to expect in about 70% of the patients with ERc+, Rn+. Patients with positive cytoplasmic estradiol- and progesterone receptors have also a response rate of about 70%. An assay of ERc, PgR and Rn appear to reinforce the precision of prediction about prognosis and the kind of therapy in some cases. The use of the DNA-binding of the ERc as marker for the ability of ERc to translocate into the nucleus should be examined further.

Breast Neoplasms↗
PubMed1975

1-H and 13-C nuclear magnetic resonance spectra of the lipids in normal and SV 40 virus-transformed hamster embryo fibroblast membranes.

Well resolved 1-H and 13-C NMR spectra were obtained with normal and SV 40-transformed cell membranes. Estimation of the ratio of 13-CT2 values of the normal to transformed cell membranes showed an increased intermolecular motion in the transformed cell membranes. The temperature dependence of the (CH2) line in the 1-H spectra in the temperature range 298-343 degrees K shows an activation energy for the lateral diffusion of the fluid phospholipid regions in the normal cell membranes while the transformed ones show practically no temperature dependence in this temperature range. The fluidity of the phospholipid region in the transformed cell membrane seems to be significantly higher than that observed in the normal cell material. These data support and extend the findings concerning the mobility of the concanavalin A binding/agglutinating sites on the surface of normal and virus-transformed cells and suggest further approaches to the study of the membrane alterations in tumor cells.

Animals↗
PubMedDate not supplied

The Medos Hakim programmable valve in the treatment of pediatric hydrocephalus.

The programmable Medos Hakim valve offers the possibility of adjusting the valve's operating pressure noninvasively. We retrospectively analyzed a series of 78 children who underwent a shunting procedure using this programmable valve within the last 4 years: 46 children underwent a primary shunt placement and 32 children underwent a shunt revision with a different valve replaced by the Medos programmable valve. There were 23 complications, 9 infections, 13 mechanical complications and 1 subileus in all children. Treatment was successful with no need for further shunt revision in 29 of the children with primary shunt placements and 27 of the children with shunt revisions. In 10 cases of overdrainage this was adequately corrected by readjustment of the valve operating pressure alone. As there are no criteria for prediction of the valve operating pressure needed for any individual patient we consider this valve to be beneficial in various forms of shunt-dependent pediatric hydrocephalus.

Adolescent↗
PubMedDate not supplied

Reversible occlusion shunt for intraventricular chemotherapy in shunt-dependent brain tumor patients.

Intraventricular chemotherapy is increasingly used in the treatment of pediatric brain tumors with leptomeningeal seeding. However, some patients are shunt dependent after surgery, probably due to adhesions in the area of surgery. To avoid drug diversion in these patients we connected the reservoir to a reversible occlusion device. Over a 2-year period a shunt value with an on-off device was inserted into the shunt assembly of eight children with various brain tumors with a poor prognosis undergoing intraventricular chemotherapy. All eight patients had tumor cells in the ventricular cerebrospinal fluid (CSF) and/or metastases by magnetic resonance imaging. The number of intraventricular drug applications ranged from 10 to 51. No shunt malfunctions or shunt-related infections occurred. The temporary closure of the shunt after drug delivery was well tolerated. In all six children with tumor cells in the ventricular CSF a negative cytology was achieved over a 3- to 8-week period.

Adolescent↗