Search PubMed⌕ Search

Biomedical subjects

P Walter

Publications and source records attributed to P Walter.

At least 307 records · Page 17Linked to original sources
PubMed1985

Beta-blockade benefits patients following a subarachnoid haemorrhage.

Previous studies have shown that ECG changes following a subarachnoid haemorrhage are associated with increased catecholamine levels, necrotic myocardial lesions, and a poor prognosis. Furthermore, beta-blockade using propranolol reverses some of the ECG changes and prevents necrotic myocardial lesions. This study was established to assess the affects of adrenergic blockade on morbidity and mortality following subarachnoid haemorrhage. Patients were admitted to the randomized double-blind between-patients study if they presented at the neurosurgical unit within 48 hours of a subarachnoid haemorrhage confirmed by lumbar puncture. Of 224 patients, the first 118 received an alpha-blocker, phentolamine 20 mg three-hourly, and either the beta-blocker propranolol 80 mg eight-hourly, or placebo. The last 106 patients received either propranolol or placebo. Treatment was continued for three weeks. Assessment at four weeks revealed significant improvements in the treated group for neurological deficit (p = 0.003) and death (p = 0.02). More treated patients underwent operation and those that did had a better outcome (p = 0.01). Assessment at one year showed that although patients had improved in both groups, patients in the treated group had significantly fewer neurological deficits (p = 0.003). There were fewer deaths in the treated group but this difference was not significant (p = 0.09). Possible mechanisms for this protective effect of propranolol may include a reduction in plasma renin activity, a reduction in pulmonary oedema, prevention of myocardial infarcts, and a reduction in cerebral oxygen requirements. It is concluded that early beta-blockade benefits patients with subarachnoid haemorrhage, in terms of fewer neurological deficits, for up to one year.

Adolescent↗
PubMed1985

Influence of native collagen on the cell cycle.

The influence of native collagen-solutions on the cell cycle of human-fibroblasts was investigated. The results point out that the phase of cell-specific function is distinctly lengthened to the debit of a reduced rate of mitosis. That seems to be desirable, because the cells of the implantation-layer would produce more rapidly and augmentedly their cell-specific product--usually collagen--and incorporation of the implanted material would occur quite earlier. This effect seems also to be responsible for the promotion of granulation of "Dermodress", a fleece of collagen I for temporary covering of debrided areas (5).

Bioprosthesis↗
PubMed1985

Cloning of the human estrogen receptor cDNA.

Poly(A)+ RNA isolated from the human breast cancer cell line MCF-7 was fractionated by sucrose gradient centrifugation and fractions enriched in estrogen receptor (ER) mRNA were used to prepare randomly primed cDNA libraries in the lambda gt10 and lambda gt11 vectors. Clones corresponding to ER sequence were isolated from both libraries after screening with either ER monoclonal antibodies (lambda gt11) or synthetic oligonucleotide probes designed from two peptide sequences of purified ER (lambda gt10). Five cDNA clones were isolated by antibody screening and five were isolated after screening with synthetic oligonucleotides. The two largest ER cDNA clones, lambda OR3 (1.3 kilobase pairs) and lambda OR8 (2.1 kilobase pairs), isolated by using antibodies and oligonucleotides, respectively, were able to enrich selectively for ER mRNA by hybrid-selection. Furthermore, lambda OR8 contains the DNA sequence expected from the two ER peptides and crosshybridizes with each of the other ER cDNA clones. These results demonstrate that the clones isolated correspond to the ER mRNA sequence. Use of lambda OR8 as a hybridization probe revealed a single poly(A)+ RNA band of approximately equal to 6.2 kilobase pairs in the ER-containing human breast cancer cell lines MCF-7 and T47D. In contrast, no hybridization was seen in the human ER-negative cell line HeLa. The same probe hybridizes to a chicken gene that is expressed in oviduct tissue as a 7.5-kilobase-pair poly(A)+ RNA.

Animals↗
PubMed1985

Structure of the signal recognition particle by electron microscopy.

The signal recognition particle (SRP) is a ribonucleoprotein consisting of six distinct polypeptide components and one molecule of small cytoplasmic RNA (7SL RNA). The particle was previously shown to function in protein translocation across and protein integration into the endoplasmic reticulum membrane. Homogeneous signal recognition particle preparations were visualized by electron microscopy (i) after negative staining, (ii) by dark-field imaging of unstained specimens, and (iii) by platinum-shadowing. The results of each of these different techniques indicate that the signal recognition particle is a rod-shaped particle 5-6 nm wide and 23-24 nm long.

Animals↗
PubMed1985

Elongation arrest is not a prerequisite for secretory protein translocation across the microsomal membrane.

Signal recognition particle (SRP) is a ribonucleoprotein consisting of six distinct polypeptides and one molecule of small cytoplasmic 7SL RNA. It was previously shown to promote the co-translational translocation of secretory proteins across the endoplasmic reticulum by (a) arresting the elongation of the presecretory nascent chain at a specific point, and (b) interacting with the SRP receptor, an integral membrane protein of the endoplasmic reticulum which is active in releasing the elongation arrest. Recently a procedure was designed by which the particle could be disassembled into its protein and RNA components. We have further separated the SRP proteins into four homogeneous fractions. When recombined with each other and with 7SL RNA, they formed fully active SRP. Particles missing specific proteins were assembled in the hope that some of these would retain some functional activity. SRP(-9/14), the particle lacking the 9-kD and 14-kD polypeptides, was fully active in promoting translocation, but was completely inactive in elongation arrest. This implied that elongation arrest is not a prerequisite for protein translocation. SRP receptor was required for SRP(-9/14)-mediated translocation to occur, and thus must play some role in the translocation process in addition to releasing the elongation arrest.

Animals↗
PubMed1985

Dermodress: a new, temporary skin substitute for extensive deep burn coverage.

A chemically treated bovine skin, Dermodress, is presented as a long-term skin substitute. Dermodress was applied over denuded surfaces of debrided deep burns and was kept in place for up to 56 days. Dermodress adheres to all contours of the debrided surfaces, has hemostatic effect and does not present any signs of infection or rejection. Dermodress can be removed in stages according to the availability of autografts, which may be applied immediately, since the exposed areas are clean and suitable for immediate grafting. Our clinical experience shows that Dermodress has most of the required properties of a long-term temporary skin substitute.

Adolescent↗
PubMed1985

Prepartal infection of the placenta with Neisseria gonorrhoeae.

Placentas from 191 consecutive deliveries were cultured for Neisseria gonorrhoeae and other bacteria before being examined histologically. N gonorrhoeae was seen on direct microscopical examination and cultured from two placentas, one of which had chorioamnionitis and the other had a granulocytic invasion of the membranes. In both patients, rupture of the membranes had occurred two hours or less before delivery, and thus after infection. A third patient was also found to have light gonococcal infection of the placenta. Six infections with group B streptococci were identified, but only one correlated with chorioamnionitis. Chorioamnionitis was observed in 16 (8.4%) and granulocytic infiltration of the membranes in 18 (9.4%) of the deliveries.

Adolescent↗
PubMed1985

[Malarial infection of the placenta. Parasitologic, clinical and immunologic aspects].

Among 1,206 pregnant women tested in Franceville (Gabon), 36.4% showed a positive parasitemia as compared to 21.9% of 154 non pregnant (p less than 0.001). Increase in the incidence of parasitemia appeared at the 4th month of pregnancy with two peaks at the 5th (44.4%) and 9th months (43.6%). Of 741 placenta studied, 33% showed plasmodial pathological changes; placental lesions were associated with a decrease in mean placental weight (26 g; p less than 0.001) and birth weight (220 g; p less than 0.001). Parasitemia during pregnancy and placental changes were more frequent in 1st or 2nd parous women and were associated with a decrease of inhibitory antibody titres in mothers at delivery, and with a synthesis of specific antibodies by the foetus i.e. with a transplacental transmission of plasmodial antigens to the foetus. Maternal inhibitory antibodies were constantly detected in cord blood and this could account for the absence of plasmodium in the 1,128 cord blood samples which have been examined.

Female↗
PubMed1985

[Placental lesions in malaria].

Malarial placenta is characterized by the presence of parasites in maternal erythroblasts, by an excess of intervillous macrophages and by an excess of perivillous fibrin deposits stained with malaric pigment. The high frequency of prematures, hypotrophic neonates and still-births in the malarial population is explained by the intervillous macrophages, which decrease the maternal blood output and the perivillous excess of fibrin which reduces the materno-fetal exchanges.

Female↗
PubMed1985

The effects of retrograde perfusion of cardioplegic solution in cardiac operations.

The effects of continuous retrograde coronary perfusion of a cardioplegic solution were investigated in 42 patients. From each patient, a needle biopsy was taken on the anterior left ventricular free wall during cardiac operations and investigated by electron microscopy. With the use of our well-standardized ultrastructural criteria of ischemic injury, we found that the retrograde perfusion technique provides cardiac protection of a quality superior to that of antegrade perfusion. This finding applied to the state of the myocardial cells. The cardiac microvessels, on the other hand, were more severely injured by retrograde perfusion, and extracellular edema occurred more frequently. It is concluded, therefore, that the retrograde perfusion of a crystalline cardioplegic solution during cardiac operation has beneficial effects on the preservation of myocardial cells in comparison to the antegrade application. Unfortunately, we also conclude that the occurrence of extracellular edema and of microvascular damage represents a serious drawback in the clinical use of this method. This technique, therefore, needs to be improved before it may routinely be applied in patients undergoing cardiac operations.

Glucose↗
PubMed1984

Role of signal recognition particle in the membrane assembly of Sindbis viral glycoproteins.

We have investigated the role of signal recognition particle (SRP) in the biosynthesis of Sindbis glycoproteins by translating the viral 26S mRNA in a wheat-germ cell-free system. SRP was shown to have no effect on the synthesis or proteolytic processing of the cytoplasmic C protein. In contrast, the membrane integration and the proteolytic processing of the viral glycoproteins PE2 and E1 were demonstrated to be SRP-dependent. In the absence of microsomal membranes, SRP caused an arrest of the synthesis of the viral glycoproteins. This arrest could be released by the addition of salt-extracted microsomal membranes. Synchronization experiments indicated that the uncleaved signal sequence of PE2 was recognized by SRP after at most 130 amino acids of PE2 had been polymerized. No apparent interaction of SRP with a putative signal sequence of E1 and/or a 6-kDa peptide could be detected.

Animals↗
PubMed1984

[Laxatives and roughage].

The mode of action, indications and contraindications of laxatives and bulkage are presented. There are only a few indications for the use of laxatives, centering mainly on bowel preparation for diagnostic and operative purposes. Frequent abuse of laxatives is observed in chronic constipation, a disease which should be treated by a high roughage diet and bulkage, preferably with bran.

Castor Oil↗
PubMed1984

[Stage-III cerebrovascular insufficiency in stenoses and occlusions of the extracranial A. carotis. An indication for surgery?].

Reconstructive surgery was performed on 93 patients with stage III cerebrovascular insufficiency, extracranial stenoses and (or) occlusions of the cerebral blood flow. Compared with the spontaneous course in acute stroke, results of surgery point towards recommending an aggressive procedure provided certain criteria are observed (time limit, absence of haemorrhagia), particularly in view of the potential mortality of the condition. Late prognosis, assessed on the basis of 40 patients subjected to neurological follow-up 4 1/2 years after the operation, can be considered favourable.

Carotid Artery Thrombosis↗
PubMed1984

[Hemodynamics and changes in compliance of the extra-thoracic capacity system following administration of prostacyclin (PGI2)].

Hemodynamic effects of prostacyclin (PGI2) given as an intravenous infusion at a rate of 8 ng/kg/min were assessed in 50 patients with coronary artery disease at the time of aortocoronary bypass surgery. 1. During steady-state neuroleptic anesthesia, after sternotomy and pericardiotomy, before cannulation of the aorta and vena cava PGI2 led to the following changes: decreases in mean arterial pressure (-24%), total peripheral resistance (-46%), left ventricular pressure (-12%) and left ventricular end-diastolic pressure (-48%), increases in heart rate (+9%), cardiac output (+41%), stroke volume (+30%) and dp/dtmax (+26%) as well as nonsignificant decreases in right ventricular filling pressure (-13%) and mean pulmonary arterial pressure (-9%) together with an unaltered rate-pressure product. 2. In a randomized double-blind study PGI2 was infused throughout the period from two minutes prior to, until termination of extracorporeal circulation. The effects on compliance of the extrathoracic venous system were analyzed on the basis of changes in venous pressure and oxygenator volume. As compared with controls, patients receiving PGI2 were found to have a significant increase in compliance (.157 ml/mm Hg X kg). Thus, in this setting, PGI2 can affect marked vasodilatation with reductions in peripheral resistance and mean arterial pressure together with increases in cardiac output and heart rate.

Clinical Trials as Topic↗