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Biomedical subjects

M Meyer

Publications and source records attributed to M Meyer.

At least 433 records · Page 24Linked to original sources
PubMed1992

[A problematic case of dysfibrinogenemia in gynecology].

Following an hymenal incision in a thirtheen years old patient a haemostaseological examination was done. A hyperfibrinolysis was supposed. In spite of a good clinical recovery values remained pathological, so we had to suspect a dysfibrinogenaemie. Only a rapid examination of all attainable family members was able to secure the diagnosis: Dysfibrinogenaemie. Dysfibrinogenaemia is not a to rare case, that such a diagnostic problem may arise in every department.

Adolescent↗
PubMed1991

Changes in ceruloplasmin activity and lactate concentration in patients at high risk of acute organ system failure.

In 241 critically ill patients at a high risk of acute organ system failure (OSF) the activity of ceruloplasmin (CPL) and the concentration of lactate in blood was measured. In patients with acute OSF the lactate concentration is high, and the CPL activity is lower in comparison with patients without OSF. These changes are particularly distinct in nonsurviving patients with OSF. The results are discussed in connection with the development of a tissue oxygen debt and the decrease of antioxidative capacity of blood.

Adult↗
PubMed1991

Acquired disorder of platelet function associated with autoantibodies against membrane glycoprotein IIb-IIIa complex--1. Glycoprotein analysis.

A patient with idiopathic thrombocytopenic purpura developed after splenectomy a thrombasthenia-like severe haemorrhagic diathesis characterized by a normal or subnormal platelet count, prolonged bleeding time, strongly reduced platelet adhesion to glass and defective platelet aggregation in response to ADP and collagen. In contrast to hereditary thrombasthenia membrane glycoproteins (GP) IIb and IIIa were normally present in the patient's platelets. Immunoelectrophoretic analysis revealed an abnormal behaviour of the patient's GP IIb-IIIa complex. Autoantibodies against GP IIb-IIIa were detected in Triton-extracted washed platelets. Incubation of normal platelets with plasma from the patient resulted in a similar immunoelectrophoretic abnormality of the GP IIb-IIIa complex indicating that bound autoantibodies (IgG) are responsible for the abnormal immunoelectrophoretic behaviour of the patient's GP IIb-IIIa complex. Platelet fibrinogen was severely reduced similar to classical thrombasthenia suggesting that the GP IIb-IIIa complex is involved in platelet fibrinogen storage.

Autoantibodies↗
PubMed1991

Stimulation of K+ transport systems by Ha-ras.

The expression of Ha-ras in quiescent NIH3T3 cells carrying a glucocorticoid-inducible human Ha-ras gene (Val-Gly mutation at codon 12) stimulates total 86Rb+ influx. This effect is predominantly due to an elevated 86Rb+ uptake through an ouabain-resistant, furosemide-sensitive system. The ouabain-sensitive Na+/K(+)-ATPase is less affected. The transport which is resistant to both inhibitors is not altered by Ha-ras. Overexpression of the Ha-ras proto-oncogene causes only a marginal increase in total 86Rb+ uptake. The stimulation of the furosemide-sensitive influx by Ha-ras is paralleled by an increase in mean cell volume which can be inhibited by furosemide. A rapid stimulation of the furosemide-sensitive Rb+ influx is also observed after addition of bombesin to growth-arrested cells. Furosemide inhibits the mitogenic response after expression of Ha-ras or addition of bombesin. Both the Ha-ras and the bombesin-induced stimulation of the furosemide-sensitive Rb+ transport can be blocked by protein kinase C depletion or the protein kinase C inhibitor staurosporine. In contrast to bombesin-induced phosphatidylinositol-4,5-bisphosphate hydrolysis which is down-modulated by Ha-ras, the stimulation of the furosemide-sensitive Rb+ influx by bombesin is elevated in Ha-ras-expressing cells. This is in accordance with the increased mitogenic activity of bombesin in Ha-ras-expressing cells.

Animals↗
PubMed1991

[Benign, focal amyotrophy].

Benign focal amyotrophy is a usually asymmetrical motor neuron disease affecting young people. Its favourable prognosis differentiates it from progressive motor neuron diseases such as the much more frequent and most severe form, amyotrophic lateral sclerosis (ALS). We report on one patient with "juvenile muscular atrophy of unilateral upper extremity" of the Hirayama type and two patients with selective amyotrophy of one calf ("wasted leg-syndrome"). In addition, we have observed three young women with selective muscle atrophy in the scapula region which has appeared stable for many years and might represent another entity of so-called benign focal amyotrophy.

Adult↗
PubMed1991

Nucleotide sequence of the 3' terminal region of lettuce mosaic potyvirus RNA shows a Gln/Val dipeptide at the cleavage site between the polymerase and the coat protein.

DNA complementary to the 3' terminal 1651 nucleotides of the genome of the common strain of lettuce mosaic virus (LMV-O) has been cloned and sequenced. Microsequencing of the N-terminus enabled localization of the coat protein gene in this sequence. It showed also that the LMV coat protein coding region is at the 3' end of the genome, and that the coat protein is processed from a larger protein by cleavage at an unusual Q/V dipeptide between the polymerase and the coat protein. This is the first report of such a site for cleavage of a potyvirus polyprotein, where only Q/A, Q/S, and Q/G cleavage sites have been reported. The LMV coat protein gene encodes a 278 amino acid polypeptide with a calculated Mr of 31,171 and is flanked by a region which has a high degree of homology with the putative polymerase and a 3' untranslated region of 211 nucleotides in length. Percentage of homology with the coat protein of other potyviruses confirms that LMV is a distinct member of this group. Moreover, amino acid homologies noticed with the coat protein of potexvirus, bymovirus, and carlavirus elongated plant viruses suggest a functional significance for the conserved domains.

Amino Acid Sequence↗
PubMed1991

Physiological profiles and therapeutic goals--graphical aids support quick orientation in intensive care.

Although present-day technical facilities and modern patient monitoring produce an overwhelming number of measured parameters in intensive care medicine, there is a great need to develop decision aids to enable ICU personnel to become quickly orientated in the pathophysiological state of the patients under their care. One possible way for the representation of a multidimensional pattern of physiological values is the graphical display of a physiological profile of a patient's state. A combination of this display and the concept of 'therapeutic goals' is well suited for reducing the complexity of the computer output and for aiding in the necessary decisions in a twofold manner: substantial deviations of a single parameter are instantly visible and may be checked for their causes, the physician obtains an impression of the most serious deviations from the intended therapeutic goal for his patient. So she/he can act to support the patient in achieving the most likely course for recovery.

Computer Graphics↗
PubMed1991

Weekly intravenous administration of recombinant human erythropoietin in infants with the anaemia of prematurity.

To study the safety and efficacy of administering human recombinant erythropoietin (rHuEPO) to infants with anaemia of prematurity, a combined phase I/II trial of weekly intravenous injections for 4 weeks was undertaken. We treated 16 infants with 10, 25, 50, 100 or 200 units/kg body weight in groups of two to four patients per dose level. They were all born prematurely (mean gestational age: 29 weeks; range 27-32), had a mean post-natal age of 42 days (range: 25-59) and haemoglobin concentration of 87 g/l (range: 72-94) when treatment was started. Four patients (25%) needed a transfusion during the trial, one at day 7 treated with 10 units/kg and 3 at days 15, 25, 29 with 100 units/kg. In the others, a progressive rise in mean haemoglobin values was seen in each group after 21 days of treatment, without a dose-dependent effect. A positive change in absolute reticulocyte counts with a peak after 7-14 days of therapy was observed with low (25-50 units/kg) but not with higher doses, with a significant difference at day 14 between 25 and 100 units/kg (P less than 0.01). A dose-limiting severe neutropenia (absolute neutrophil count less than 0.5 x 10(9)/l) occurred transiently in five patients, with doses greater than 25 units/kg. No infectious complication and no sign of iron deficiency were observed. Weekly low doses of rHuEPO appear safe, convenient to administer and able to induce a reticulocytic response in infants with anaemia of prematurity. A phase III placebo-controlled trial is needed to confirm these results. Neutropenia associated with rHuEPO administration in infants might be related to their stage of human ontogeny.

Anemia, Neonatal↗
PubMed1991

Changes of neuron-specific enolase concentration in plasma after cardiac arrest and resuscitation.

The concentration of neuron-specific enolase (NSE) was measured in plasma of 18 patients after cardiac arrest and resuscitation (14 nonsurvivors and 4 survivors). In all patients, the NSE concentration was significantly higher in comparison to reference values. The highest concentration was measured in nonsurvivors. Time-course investigation in the first 24 h after cardiac arrest was performed in five patients. Two nonsurvivors and one survivor of the five patients showed a significant rise, and a NSE peak concentration of 42.7 micrograms/L, 13.6 micrograms/L, and 10.5 micrograms/L, respectively, was found 10-19 h after cardiac arrest.

Brain Ischemia↗
PubMed1991

Effects of 10 days 6 degrees head-down tilt on the responses to fluid loading and lower body negative pressure.

In an international collaborative project six normal male subjects were studied before, during and after 10 days 6 degrees HDT. Fluid intake was controlled at 40 ml/(kgbw day). Urine volume and body weight were determined daily. Fluid loading and LBNP were performed in all three phases of the study. Body weight diminished by 2.6% because of fluid loss. Blood volume diminished by 13%. The responses to fluid loading were similar in the three phases of the study. Sixty minutes after end of infusion only 5.5% of the infused saline remained in the intravascular compartment. Excess interstitial fluid was eliminated in the next 24 hs but a negative balance was recorded also in the following day. The compliance of the lower limbs expressed as the rate of limb volume change/unit LBNP change was increased at the end of the HDT phase and during the post HDT phase. The set point of intravascular volume was defended, as shown by the response to FL. HDT increased the compliance of the lower limbs.

Adult↗
PubMed1991

A study of the effects of photodynamic therapy on the normal tissues of the rabbit jaw.

Photodynamic therapy (PDT) is an anti-cancer treatment which involves the systemic administration of a photosensitising drug which is preferentially absorbed by tumour tissue. Relatively little drug should be absorbed by the surrounding normal tissues. Tumour destruction is achieved when the tumour is illuminated with light of a wavelength which activates the photosensitising drug thereby inducing a cytotoxic reaction. However studies in many tissues have shown that the hoped for tumour selectivity is rarely achieved. Using the rabbit mandible and gingiva as our models we have studied the effects of various doses of PDT on the tissues of the oral cavity, namely mucosa, bone, muscle and salivary gland. The photosensitiser used was di-sulphonated aluminium phthalocyanine. Results show that whereas bone is extremely resistant to PDT the other tissues are vulnerable to it. In the case of muscle and salivary gland this susceptibility is very much dose related. In salivary tissue necrotising sialometaplasia was observed in areas of the gland adjacent to those that had undergone necrosis. All tissues were noted to heal or regenerate well following PDT injury.

Animals↗
PubMed1991

Auriculatin 4'-O-Glucoside: A New Prenylated Isoflavone Glycoside from Erythrina eriotricha1.

In addition to known compounds, sigmoidin C and 8-(3,3-dimethylallyl)-erythrinin C, also called senegalensin, a new isoflavone glycoside designated auriculatin 4'- O-glucoside was isolated from the chloroform extract of the stem bark of ERYTHRINA ERIOTRICHA. Its structure was elucidated as 7,6-(2''',2'''-dimethyl-2 H-pyrano)-2',5-dihydroxy-8-(3,3-dimethylallyl)-isoflavone 4'- O-beta- D-glucoside on the basis of spectroscopic methods and chemical evidence.

Journal Article↗
PubMed1991

Insulin-like growth factor I (IGF-I) and insulin binding to erythrocytes of normal prepubertal children and adults.

Erythrocyte insulin-like growth factor I (IGF-I) and insulin receptors were characterized in 10 normal prepubertal children (5 girls and 5 boys) aged 4-11 yrs and 10 normal adults (4 women and 6 men) aged 32-47 yrs. erythrocytes were purified from 5 ml of blood by Ficoll-Paque gradient centrifugation. Reticulocytes count in the erythrocyte suspensions were lower than 1%. Insulin and IGF-I binding assays were performed simultaneously. Maximal percent binding of [125I] labelled IGF-I was significantly higher in prepubertal children than in adults (8.7 +/- 0.7% versus 6.2 +/- 0.5% at a concentration of 5 x 10(9) erythrocytes/ml). Scatchard analysis revealed the high affinity constant was better in prepubertal children (Ka = 4.6 +/- 1.3 nM-1 versus 1.8 +/- 0.2 nM-1), whereas the binding capacity was similar (5.8 +/- 1.1 versus 7.7 +/- 0.8 high affinity binding sites/cell). In both groups, unlabelled IGF-I inhibited tracer-binding half maximally at about 1 nM. Insulin was 100-fold less potent. In adults, specific binding of [125I] labelled IGF-I was higher in women (7.6 +/- 0.7%) than in men (5.3 +/- 0.4%). No significant difference was observed in maximal specific binding of [125I] labelled insulin between prepubertal children (8.2 +/- 0.5%) and adults (7.2 +/- 0.7%). In both groups, competition by unlabelled insulin for [125I] labelled insulin binding gave 50% displacement for approximately 0.25 nM and IGF-I was about 80-fold less potent. Both IGF-I and insulin binding parameters were not significantly correlated with plasma hormone levels. In prepubertal children, the high-affinity IGF-I receptors number decreased with increasing high-affinity insulin receptors number.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Discrete-time event history analysis using segmented hazards.

Event history analysis is a means of explaining variation in the timing of events in individual life histories. This article describes methods for overcoming two difficult problems likely to be encountered in applications of event history analysis to studies of aging and human development. First, in many studies the ages of occurrence of critical life events are recorded in discrete units such as years, but the probability distributions of life events are usually specified in continuous-time form. We show how to estimate models for discrete-time data based on an underlying continuous-time specification. Second, the standard distributions for life events often fail to capture the complex age-dependence seen in actual data. We show how to construct a model using segmented hazards, that is, a composite of different functions for different segments of time. To illustrate these points, we study the age of first intercourse of 11,883 subjects from the National Longitudinal Study of Youth.

Adolescent↗