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Biomedical subjects

M Peter

Publications and source records attributed to M Peter.

At least 37 records · Page 2Linked to original sources
PubMed1990

Identification of major nucleolar proteins as candidate mitotic substrates of cdc2 kinase.

Following the identification of the cdc2 kinase as a major element controlling entry of cells into mitosis, it is important to define the physiological target range of this enzyme. Here, we demonstrate that two major nucleolar proteins, nucleolin and NO38, are highly phosphorylated during mitosis. Importantly, the two nucleolar proteins are also phosphorylated by highly purified starfish cdc2 kinase in vitro, on sites that correspond to those observed specifically during mitosis in vivo. A repeated motif (TPXKK) is identified as the likely mitotic phosphoacceptor site in nucleolin, in that a synthetic peptide mimicking this site functions as both a substrate and a competitive inhibitor of cdc2 kinase. These results identify two novel candidate substrates for cdc2 kinase, and they implicate protein phosphorylation in controlling mitotic changes in nucleolar structure and activity.

Amino Acid Sequence↗
PubMed1990

Assessment of chromosome 22 anomalies in neurinomas by combined karyotype and RFLP analyses.

We report the cytogenetic study of 28 neurinomas; sixteen of them were also analysed using 11 polymorphic DNA markers for the loss of alleles of chromosome 22. Partial or total loss of chromosome 22 was found in nine cases. The results of the two approaches appear homogeneous, however, three tumors that yielded only cells with normal karyotypes demonstrated loss of constitutional heterozygosities. One of the tumors, which displayed an isodicentric or isopseudodicentric 22, was obtained in a patient with von Recklinghausen neurofibromatosis. It appears that loss of chromosome 22 is a characteristic of neurinomas whatever their context of occurrence.

Alleles↗
PubMed1990

[Ectopic ureteral junction as a cause of chronic pelvic pain and treatment refractory vaginal discharge].

We report on a 22-year old patient with an ectopic ureter ending in the vestibulum of the vagina without genital malformations. Generally, the diagnosis of this anomaly will have already been made in childhood, because of enuresis uretica and therapy-resistant vaginal discharge. The methods of diagnosis leading to this anomaly, which is rare at that age, and the therapeutic requirements are shown.

Abdominal Pain↗
PubMed1990

Scintigraphic study of radiolabelled interferon-alpha in osteosarcoma patients.

Interferon-alpha is currently under evaluation as an antineoplastic agent in several types of tumour. Despite its clear in vitro effects, the effectiveness of interferon in vivo is limited. To assess whether this discrepancy reflects pharmacokinetic limitations, the authors analysed interferon distribution in 2 osteosarcoma patients by scintigraphy using 123I-interferon-alpha-2a. Numerical analysis of the scintigraphic records demonstrated that the main organs of elimination were the kidneys, when the calculation was made on the basis of surface area. On the other hand, the apparent total uptake by liver (whose projection surface--i.e. the area exposed to the lens--is greater) was higher, reaching about 25 to 30% of the injected dose. The projection surface of the tumour was able to take up radiolabelled interferon in both cases, resulting in a 4-fold increase in the external radiation count compared with the equivalent region of the contralateral limb (although it is not possible to determine whether the label is present on the tumour itself or on the surrounding inflammatory cells). Thus, interferon-alpha seems able to reach at least the immediate neighbourhood of osteosarcoma mass.

Adult↗
PubMed1989

Cloning and sequencing of cDNA clones encoding chicken lamins A and B1 and comparison of the primary structures of vertebrate A- and B-type lamins.

Nuclear lamins are intermediate-filament-type proteins forming a fibrillar meshwork underlying the inner nuclear membrane. The existence of multiple isoforms of lamin proteins in vertebrates is believed to reflect functional specializations during cell division and differentiation. Although biochemical criteria may be used to classify many lamin isoforms into A- and B-type subfamilies, the structural features distinguishing the members of these subfamilies remain to be characterized fully. Here, we report the complete primary structures of chicken lamins A and B1, as they are deduced from cloned cDNAs; in the accompanying paper we present the complete sequence of lamin B2, a second avian B-type lamin. Comparisons of the chicken lamin sequences with each other and with those of other lamins allow us to establish structural features that are common to members of both subfamilies. Conversely, multiple sequence alignments make it possible to identify a number of structural motifs that clearly differentiate B-type lamins from A-type lamins. With this information at hand, we attempt to correlate different biochemical properties of A- and B-type lamins with the presence or absence of specific sequence motifs.

Amino Acid Sequence↗
PubMed1989

[Lipoma of the corpus callosum in an infant with seizures].

A 3 month-old boy was admitted because of short convulsions commencing with a peculiar grin. A lipoma of the corpus callosum was diagnosed by X-ray of the skull, cranial ultrasound, CT and magnetic resonance tomography. Following treatment with phenobarbital convulsions were not observed any longer. Surgical removal of the tumour was not indicated.

Brain Neoplasms↗
PubMed1987

Sequence and identification of the nucleotide binding site for the elongation factor Tu from Thermus thermophilus HB8.

Two structural genes for the Thermus thermophilus elongation factor Tu (tuf) were identified by cross-hybridization with the tufA gene from E. coli. The sequence of one of these tuf genes, localized on a 6.6 kb Bam HI fragment, was determined and confirmed by partial protein sequencing of an authentic elongation factor Tu from T. thermophilus HB8. Expression of this tuf gene in E. coli minicells provided a low amount of immuno-precipitable thermophilic EF-Tu. Affinity labeling of the T. thermophilus EF-Tu and sequence comparison with homologous proteins from other organisms were used to identify the guanosine-nucleotide binding domain.

Amino Acid Sequence↗
PubMed1987

A surgical strategy for femoro-crural reconstruction.

In order to improve the results of femoro-distal bypass grafting a number of tactics are suggested. The bypass distance should be kept to a minimum using autologous vein as a bridge between open segments. Anastomoses should be end to end wherever possible because of their haemodynamic characteristics and collaterals should be preserved by a proximal end to side anastomosis. When salvaging the extremity the dissection should be kept to a minimum in tissue which is already ischaemic.

Aged↗
PubMed1987

Evidence of a selective major vascular marginal pool of lymphocytes in the lung.

The size and mobilization of the pulmonary vascular pool of lymphocytes was studied in young pigs. Blood lymphocytes, labeled in vitro with a fluorescent dye, were injected either intravenously or into the left heart. Comparable high numbers of lymphocytes were found in the lung after 30 min, demonstrating a specific homing of lymphocytes to the lung vascular bed. When the left lung was perfused with a cell-free medium for as long as 4 h in vitro, a continuous venous release of lymphocytes was found that resulted in about 1.5 x 10(9) lymphocytes and 5.7 x 10(6)/min leukocytes. Peripheral blood lymphocytes were labeled with 51Cr in vitro and injected intravenously. Fifteen minutes or 1 day later the lungs were perfused, and the release of cell-bound radioactivity was measured. The data indicate the existence of a large intravascular pulmonary lymphocyte pool. The sequestration of lymphocytes in the lung in many lymphocyte migration studies is not a removal of effete cells but a physiologic phenomenon.

Animals↗
PubMed1986

Modulation of LH-secretion in ovariectomized ewes by constant infusions of oestradiol and 4-hydroxyoestradiol: effects of varying infusion times and of high oestrogen doses.

Ovariectomized ewes were infused for different times (2-24 h) during the breeding season (September to February) with oestradiol (E2, 2 micrograms/h) or the catecholoestrogen 4-hydroxyoestradiol (4-OHE2, 10 micrograms/h). At these infusion rates comparable plasma levels of E2 and 4-OHE2 were obtained when steady state was reached after 3 h (E2: 20 +/- 4 pg/ml; 4-OHE2: 22 +/- 3 pg/ml). When E2 was infused for at least 6 h, all animals had significant LH-surges, starting 14-16 h after the beginning of oestrogen treatment, even when E2 was infused for up to 24 h. 4-OHE2, however, had only to be infused for 4 h to induce significant LH-surges in all animals tested. When E2 was infused for 12 h at a rate of 100 micrograms/h, the LH-surges in these ewes were significantly lower than the LH-surges in the same animals treated for 12 h with E2 at a rate of 2 micrograms/h. These data indicate: Once E2 has been administered at a specific infusion rate for a critical time period of 6 h, LH-surges occur, no matter whether the E2-infusion is continued or stopped. For the catecholoestrogen 4-OHE2 this critical time period amounts only to 4 h, if comparable plasma levels of either oestrogen are achieved. This might hint at a prolonged intracellular action of 4-OHE2 as compared to E2. At extremely high infusion rates of E2 (100 micrograms/h for 12 h) the positive oestrogen effect is significantly impaired, a finding supporting the concept of a bell-shaped dose-response relationship between oestrogens and their positive effect on LH-secretion.

Animals↗
PubMed1979

Blood conservation during myocardial revascularization.

A prospective study of blood utilization in 50 consecutive patients undergoing elective coronary artery bypass was undertaken. Blood was removed from all patients during induction of anesthesia and reinfused after bypass (mean, 675 ml). Intraoperatively, all discard suction was routed through a regionally heparinized collecting and processing system, and the resulting red cell concentrate was transfused. At the conclusion of bypass, all blood remaining in the pump oxygenator was retained for transfusion. After operation, shed mediastinal blood was collected in a sterile, filtered collection system and transfused. Normovolemic anemia was accepted in hemodynamically stable patients. The mean amount of patients' blood salvaged by the intraoperative system was 259 ml (range, 0 to 724 ml) and by the postoperative system, 194 ml (range, 0 to 564 ml). Ninety-four percent (47/50) of the patients received no bank blood or blood products during their hospital stay. No patients received bank blood intraoperatively or during the first 24 hours following operation. There were no complications attributable to blood salvage techniques.

Adult↗
PubMed1979

Footedness of left- and right-handers.

The performance on a simple tapping task of the hands and feet of left- and right-handers was tested. Right-handers tapped faster with their right hand and right foot. Left-handers tapped faster with their left hand and right foot. Thus, footedness follows handedness in right-handers but not in left-handers. Left-handers showed smaller left/right differences than right-handers in both hand and foot performance. These data are in loose agreement with the modified genetic theory of handedness proposed by Annett (Hand preference and the laterality of cerebral speech, Cortex, 1975).

Adolescent↗
PubMed1975

Thigh emphysema and hip pain secondary to gastrointestinal perforation.

A patient presenting with thigh emphysema and hip pain may suggest intra-abdominal pathology. Three new and 19 previously reported cases of thigh emphysema secondary to bowel disease are reviewed. The thigh and hip manifestations can obscure the primary intra-abdominal process either due to the obvious emphysema or to the obtunded abdominal signs secondary to associated neuropathy. Only one of 22 patients with thigh emphysema secondary to bowel perforation had gas gangrene. Early diagnosis of this clinical association is essential since eight of the 11 deaths occurred within a few days after admission. Right-sided thigh emphysema suggests appendicitis, whereas left-sided emphysema is more likely to be secondary to left colonic diverticulitis or carcinoma.

Appendicitis↗
PubMedDate not supplied

The role of the head and tail domain in lamin structure and assembly: analysis of bacterially expressed chicken lamin A and truncated B2 lamins.

Nuclear lamins like cytoplasmic intermediate filament proteins exhibit a characteristic tripartite domain structure with a segmented alpha-helical rod domain flanked by an N-terminal head and a C-terminal tail domain. To examine the influence of the head and tail domains on the structure and assembly properties of nuclear lamins, we have engineered "headless," "tailless," and "rod" chicken lamin B2 cDNAs and expressed them in Escherichia coli. A full-length chicken lamin A cDNA was also expressed in E. coli, and the recombinant protein compared with the structure and assembly properties of full-length chicken lamin B2 (E. Heitlinger et al. (1991) J. Cell Biol. 113, 485-495). As with lamin B2, at their first level of structural organization, lamin A and the headless lamin B2 formed myosin-like dimers consisting of a 51- to 52-nm-long tail flanked by two globular heads at one end. Similarly, the tailless and rod lamin B2 fragments formed tropomyosin-like dimers consisting of a 51 to 52-nm-long rod. In contrast to the lateral mode of association of cytoplasmic IF dimers into four-chain tetramers, at their second level of structural organization, lamin A dimers, just as lamin B2 dimers (E. Heitlinger et al. (1991) J. Cell Biol. 113, 485-495), associated longitudinally to form polar head-to-tail polymers. Whereas dimers made of the truncated B2 headless and rod lamins had lost their propensity to associate head-to-tail, tailless lamin B2 dimers revealed an enhanced head-to-tail association. Finally, at their third level of structural organization, rather than assembling into stable 10-nm filaments, both lamin A and the three truncated B2 lamins formed paracrystalline arrays exhibiting distinct transverse banding patterns with axial repeats of either 24 or 48-49 nm depending on the species.

Animals↗