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J Meyer

Publications and source records attributed to J Meyer.

At least 649 records · Page 36Linked to original sources
PubMed1991

[Diagnosis of pleural effusions and atelectases: sonography and radiology compared].

In a prospective study it was shown that chest ultrasonography is superior to conventional x-ray diagnosis of recumbent patients in diagnosing pleural effusion and lung atelectasis. In 110 supine radiographs we found a sensitivity of 47% and a specificity of 71% for right pleural effusions and a sensitivity of 55% and a specificity of 93% for left pleural effusions in comparison to 110 sonographic examinations. The results of supine radiographs in detection of atelectasis were less efficient: sensitivity for the right side: 7%; sensitivity for the left side: 13.5%. Hence, the knowledge of chest ultrasonographic diagnosis can improve the interpretation of supine radiographs.

Critical Care↗
PubMed1991

Cardiopulmonary effects of constant-flow ventilation in experimental myocardial ischaemia.

The cardiopulmonary effects of constant-flow ventilation were investigated in dogs with normal heart function (control-phase, n = 14) and after development of acute myocardial ischaemia (ischaemia phase, n = 14). Heated, humidified and oxygen-enriched air was continuously delivered with an inspiratory flow rate of 1.21.kg-1.min-1 via two catheters positioned within each mainstem bronchus. Continuous positive pressure ventilation with a positive end-expiratory pressure of 0.5 kPa (5 cmH2O) was used as a reference. During control, neither continuous positive pressure ventilation nor constant-flow ventilation showed impairment of cardiopulmonary performance. Oxygenation and CO2 removal were more efficiently achieved by continuous positive pressure ventilation (P less than or equal to 0.05). Acute myocardial ischaemia was induced by occlusion of the left anterior descending (LAD) coronary artery; measurements during the ischaemia phase were performed 60 min following LAD occlusion. Myocardial ischaemia resulted in moderate changes of cardiac output, left ventricular end-diastolic pressure and dP/dtmax. Both modes of ventilation were well tolerated in the ischaemia phase, and cardiovascular performance revealed no significant differences between continuous positive pressure ventilation and constant-flow ventilation. Haemodynamic parameters could be more precisely assessed during constant-flow ventilation. Oxygenation deteriorated, but hypoxaemia did not occur in any animal and CO2 elimination remained unchanged. It is concluded that 'non-conventional' ventilation by continuous intrabronchial gas flow maintains adequate gas exchange with no adverse effects on haemodynamics in dogs with acute myocardial ischaemia. Constant-flow ventilation may be advantageous in the experimental setting to study cardiac function without cyclic heart-lung interaction due to airway pressure alterations.

Animals↗
PubMed1991

Effect of recombinant bovine somatotropin (BST) on physiological parameters and on milk production in German Fleckvieh cows.

The efficacy of injecting primiparous cows of a dual purpose breed (Deutsches Fleckvieh) with a BST prolonged release formulation (500 mg Sometribove s.c.) was tested in a cross-over design. Seven cows were given 500 mg BST in the 10th through 19th week of lactation and a placebo in the 24th through 33rd week. A second group of seven cows received a placebo in the 10th through 19th week and BST in the 24th through 33rd week. Blood samples were taken from the jugular vein (via a permanent cannula) in the 13th, 17th, 23rd, 27th and 31st week of lactation over a period of 24 hrs at 30 min intervals. During the periods of BST treatment the amount of FCM (amount of milk corrected to 4% fat content) was higher in treated than in non-treated animals by 3.6 kg (19.8%) and 3.2 kg (22.5%) respectively. Milk fat levels were elevated significantly during both treatment periods. Milk protein concentration showed a significant rise during the second half of lactation only. There was no influence on lactose content. Blood concentration of somatotropin and IGF-I rose during treatment by a factor of 3-4. Insulin, T3, T4 and FTI as well as glucose, urea and GOT showed no changes or changes within physiological ranges. Free fatty acids and beta-hydroxybutyrate rose during treatment.

Animals↗
PubMed1991

The susceptibility of cerebral endothelial cells to astroglial induction of blood-brain barrier enzymes depends on their proliferative state.

Primary cultures of brain capillary endothelial cells (BCECs) were used to investigate the induction of blood-brain barrier (BBB) characteristics in vitro. Enzymatic activities of gamma-glutamyltranspeptidase (gamma-GT) and alkaline phosphatase (ALP) were taken as indicators for the expression of the BBB phenotype. We were able to show that a coculture system with a direct cell-cell contact between astroglial cells and BCECs is the necessary precondition for an increase of these enzyme activities that are lost in pure BCEC cultures. Coculture with both astrocytes and C6-glioma cells reestablishes the BBB phenotype whereas conditioned media as well as an astrocyte-derived extracellular matrix were ineffective. The susceptibility of the BCECs to an astroglial stimulus depends on the proliferative state of the BCECs. Cells in an early highly proliferative culture phase were stimulated to express an enzymatic activity level similar to the in vivo situation. Confluent BCEC monolayers were not induced at all. With the ALP we observed a spatial induction within a BCEC colony. Astrocyte-induced ALP activity was first observed at an outer belt of BCEC colonies in direct contact with the astrocyte layer. However, this signal is transferred to the center of the colony with time in culture. We conclude that direct contact of BCECs with astroglial cells is necessary for the induction of the BBB phenotype in cultured BCECs and that this signal may be transferred from induced to noninduced BCECs.

Alkaline Phosphatase↗
PubMed1991

Sequence of changes in rat buccal mucosa induced by zinc deficiency.

In weanling rats, after receiving a zinc-deficient diet (less than 1 ppm) for 4 wk, the buccal mucosa appears hyperplastic. This study determines changes at earlier stages of the lesion. After 9 days of deficiency, the keratin layer had partially converted to parakeratosis and thickened, and the size of the capillary bed was increased. After 18 days, the keratin layer was fully parakeratotic and thickened further. The cellular layer was thickened. The mitotic rate was doubled and rete ridges were convoluted. After 27 days, the keratin and cellular layers were further thickened, and the mitotic rate remained elevated. The rete ridges were further convoluted. The number of mast cells was doubled and the size of the vascular bed had increased further. These findings suggest early and late interactions between the epithelium and lamina propria. After four days on a control diet following 27 days of zinc deficiency, the mucosa returned normal.

Animals↗
PubMed1991

Mutagen specificity for 71 lines resistant to barley powdery mildew race D1 and isolated in four highbred barley varieties.

A search for practically valuable mutant genes conferring resistance to barley powdery mildew applied a screening system where four commercial varieties of barley without known genes for resistance were tested to the successful mildew race D1. Ionizing radiations and chemicals were used as mutagens. Among the 71 resistant lines isolated, 28 were recessive and belonging to locus ml-o, and 43 were dominant. In tests to a panel of 30 different races of barley powdery mildew, 27 among the dominant lines showed resistance spectra similar or identical to those characterizing 7 previously known genes. The remaining 16 lines formed 12 groups displaying new spectra of resistance to the panel of mildew races. Taking the frequency of recessive mutations in locus ml-o as a standard, ionizing radiations were significantly more efficient mutagens for producing dominant resistance to mildew. In spite of some possible sources of contaminant dominant resistance genes, the evidence points at a vast majority of the isolated lines representing genuine dominant mutations. Being produced in a single mutational step, such dominant genes for resistance offer evidence of having a regulatory function, regulating aspects of the host metabolism of importance for or interfering with the pathogen development.

Ascomycota↗
PubMed1991

Galactokinase encoded by GAL1 is a bifunctional protein required for induction of the GAL genes in Kluyveromyces lactis and is able to suppress the gal3 phenotype in Saccharomyces cerevisiae.

We have analyzed a GAL1 mutant (gal1-r strain) of the yeast Kluyveromyces lactis which lacks the induction of beta-galactosidase and the enzymes of the Leloir pathway in the presence of galactose. The data show that the K. lactis GAL1 gene product has, in addition to galactokinase activity, a function required for induction of the lactose system. This regulatory function is not dependent on galactokinase activity, as it is still present in a galactokinase-negative mutant (gal1-209). Complementation studies in Saccharomyces cervisiae show that K. lactis GAL1 and gal1-209, but not gal1-r, complement the gal3 mutation. We conclude that the regulatory function of GAL1 in K. lactis soon after induction is similar to the function of GAL3 in S. cerevisiae.

Alleles↗
PubMed1991

Short and long term results after intracoronary stenting in human coronary arteries: monocentre experience with the balloon-expandable Palmaz-Schatz stent.

OBJECTIVE: Intracoronary stenting was designed to overcome acute complications after percutaneous transluminal coronary angioplasty and to achieve a reduced rate of restenosis, both of which are major limitations of this well accepted method for treating coronary heart disease. This report describes the experience at one centre with the implantation of balloon-expandable Palmaz-Schatz stents and focuses on device related complications and the short and long term angiographic outcome. DESIGN: A retrospective data analysis. PATIENTS: Stenting was attempted in 50 patients. Restenosis after an initially successful angioplasty procedure, inadequate postangioplasty results, saphenous coronary bypass stenoses, and bail-out situations were regarded as indications. MAIN OUTCOME MEASURES AND RESULTS: In 49 of 50 attempted patients 61 stents (1-4 per patient) were implanted. Delivery problems occurred in three patients and were successfully overcome in two patients. Bail-out situations were successfully managed in 16 patients. Complications included acute thrombus formation within the stent immediately after implantation in one patient, which was successfully treated by thrombolysis. One patient was sent for bypass surgery the day after implantation; another died 10 days after implantation for unknown reasons. Subacute stent thrombosis occurred in seven patients 5-9 days after implantation and was successfully treated by thrombolysis or balloon angioplasty in five patients. Bleeding complications occurred in nine patients, five of whom required blood transfusions. Angiography showed long term vessel patency after 4-6 months in 31 (76%) of the 41 patients who were followed up, restenosis in six (14%), and reocclusion in four (10%). Late restenosis or reocclusion was found in five (15%) of 33 patients with a single stent in contrast to five (63%) of eight patients with multiple stents. CONCLUSIONS: Balloon-expandable intracoronary stenting is a feasible method for treating the acute complications of balloon angioplasty. It reduced the rate of restenosis for single stent implantation. Subacute thrombotic events must be regarded as previously unknown and serious complications.

Adult↗
PubMed1991

Lyme borreliosis.

Borrelia burgdorferi, the etiologic agent of Lyme disease, was the topic of an international conference in Stockholm which assembled 500 scientists from all over the world. About 300 oral and poster presentations revealed many new details on the complex life history of this bacterium, its molecular characteristics, the clinical consequences of human and animal infections, new diagnostic procedures and therapeutic regimens.

Animals↗
PubMed1991

Cellular and molecular mechanisms for reduced interleukin 4 and interferon-gamma production by neonatal T cells.

The mechanisms by which T lymphocytes acquire the capacity to produce interleukin 4 (IL-4) and other lymphokines during intrathymic and extrathymic development are poorly understood. To gain insight into this process, we determined the capacity of human neonatal and adult T lineage cell populations to produce IL-4 after polyclonal activation. IL-2 and interferon-gamma (IFN-gamma) production were studied in parallel, since their production by neonatal T cells is known to be similar or diminished, respectively, compared to adult T cells. Production of IL-4 by neonatal CD4+ T cells and IFN-gamma by neonatal CD4+ and CD8+ T cells was markedly lower compared with analogous adult cell populations, whereas IL-2 production was similar. Transcription of IL-4, as determined by nuclear run-on assays, and IL-4 mRNA-containing cells, as determined by in situ hybridization, were undetectable in neonatal T cells, whereas both were detectable in adult T cells. IFN-gamma transcription and IFN-gamma mRNA-containing cells were reduced in neonatal T cells compared with adult T cells. Reduced lymphokine production by neonatal T cells correlated with their lack of a CD45R- (putative memory T cell) population; cells with this surface phenotype comprised 30-40% of the adult CD4+ T cells and were highly enriched for IL-4 and IFN-gamma, but not IL-2 production. IL-4, IFN-gamma, and IL-2 mRNA expression by neonatal CD4+CD8- thymocytes was similar to that found in circulating neonatal CD4+ T cells. Taken together, these findings suggest that the extrathymic generation of memory T cells during postnatal life may result in an increased capacity for IL-4 and IFN-gamma gene expression. In addition, IFN-gamma and IL-2 mRNA were significantly more abundant than IL-4 mRNA in activated neonatal CD4+CD8- thymocytes and CD4+ T cells, as well as adult CD4+ CD45R- T cells. Therefore, the capacity of T lineage cells to express the IL-4 gene may be more restricted compared to other lymphokine genes beginning in intrathymic development. This restricted capacity appears to persist during postnatal extrathymic maturation of T cells.

Adult↗
PubMed1991

The inheritance of alcohol consumption patterns in a general population twin sample: I. Multidimensional scaling of quantity/frequency data.

Quantity/frequency data on alcohol consumption were obtained by mailed questionnaire from 2,903 same-sex monozygotic and dizygotic Australian twin pairs. Nonmetric multidimensional scaling was applied to these data. A three-dimensional solution was required to account for the observed pattern of twin concordances for alcohol consumption. These results suggest separate determination of abstinence, frequency of consumption and quantity consumed when drinking, rather than inheritance of a single continuum of overall consumption level.

Adolescent↗
PubMed1991

The inheritance of alcohol consumption patterns in a general population twin sample: II. Determinants of consumption frequency and quantity consumed.

Genetic models were fitted to self-report data on frequency of alcohol consumption and average quantity consumed when drinking, from 3,810 adult Australian twin pairs. Frequency of consumption is determined both by an abstinence dimension, which is strongly influenced by shared environmental effects but not by genetic effects, and by an independent frequency dimension, which is influenced by genetic effects in both sexes and possibly by shared environmental affects in men. Quantity of alcohol consumed is likewise determined by an environmental abstinence dimension and by an independent and partly heritable quantity dimension. The best-fitting model allowed for two routes to abstinence: those who were not abstainers by virtue of their position on the abstinence dimension could nonetheless become abstainers by their position on the second, frequency (or quantity) dimension. Heritability estimates were 66% in women and 42-75% in men, for frequency; and 57% in women and 24-61% in men, for quantity.

Adult↗
PubMed1991

Changes in hormones, metabolites, and milk after treatment with sometribove (recombinant methionyl bST) in Deutsches Fleckvieh and German black and white cows.

Twelve second-lactation Deutsches Fleckvieh cows, (FV, a dual-purpose breed) and 12 German Black and White (BW, a dairy breed) were used to evaluate similarities and differences in the response to a prolonged-release formulation of sometribove (N-methionyl bovine somatotropin, bST). Cows were milked twice daily and fed a basic diet (70% corn silage, 30% alfalfa hay) ad libitum plus 1 kg of concentrate. Additionally, concentrates and supplements were offered at the rate of 1 kg for each 22 kg of milk produced above 12 kg/d. Six cows of each breed were treated s.c. with 500 mg of sometribove at 14-d intervals from wk 9 to 29 postpartum (pp). Blood was collected by jugular vein puncture once weekly from wk 7 to 33 pp and daily for 14 d after the first and last (11th) injection of bST. Somatotropin (ST), insulin-like growth factor I (IGF-I), insulin, thyroid hormones, nonesterified fatty acids (NEFA), liver enzymes, and blood metabolites were evaluated. During bST treatment, plasma ST increased significantly on d 7 in both breeds and then decreased on d 14 after injection. Plasma IGF-I was positively correlated with ST. Plasma NEFA were high on d 7 and decreased on d 14. In response to bST, the average milk yield increased for FV and BW cows by 5.1 kg/d (29.7%) and 5.0 kg/d (28%), respectively, and 4% fat-corrected milk (FCM) increased by 5.0 kg/d (28%) and 5.3 kg/d (19.9%), respectively. Milk content of fat, protein, lactose, number of somatic cells, and body weight were similar across treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Acute intermittent porphyria and primary liver-cell carcinoma.

A patient known with acute intermittent porphyria who developed primary liver-cell carcinoma is described. No other risk factors were found. A possible association of acute intermittent porphyria with the development of primary liver-cell carcinoma has been suggested in recent, mainly Scandinavian literature. So far this association has never been described in The Netherlands.

Acute Disease↗
PubMed1991

[The significance of somatostatin for decreasing peri- and postoperative complications in Whipple operation].

During the period from 1987-1990 152 patients underwent a Whipple procedure at the Department of General Surgery of Münster University Hospital. 27 operations were performed for chronic pancreatitis (17.8%), 52 for pancreatic (34.2%) and 73 (48.0%) for ampullary carcinoma. All patients received Somatostatin (6 mg/24 h) postoperatively for five days. These patients were compared with those of a former series who were identically operated but did not receive Somatostatin. In-hospital-mortality was reduced from 10.7% to 4.6%. Additionally the frequency of postoperative pancreatic fistulas was reduced among the nonlethal complications.

Ampulla of Vater↗
PubMed1991

[The historical development of resection surgery in pancreatic carcinoma].

Based on the pitfalls of the past the development of pancreatic resection therapy is outlined, starting with the first distal pancreatic resection in 1882 performed by Trendelenburg. Giving details of operations from the first decades of this century the Whipple operation is described as the early cornerstone in the history of radical therapy of pancreatic cancer. Summarizing the disappointments of the seventies gives the clue to the present situation with a modified Whipple operation as the standard curative approach to pancreatic carcinoma today. Additionally, various aspects of palliative therapy for pancreatic carcinoma are discussed.

Europe↗
PubMed1991

[Stress echocardiography: a sensitive method in diagnosis of coronary heart disease].

Prevalence of coronary artery disease requires sensitive diagnostic methods for screening and follow-up. The sensitivity of stress-ECG is low, 201-thallium scintigraphy is more sensitive but has the disadvantages of radiation and costs. Improved echocardiographic resolution with better identification of endocardial border as well as digital imaging technique have increased the interest in stress echocardiography as a diagnostic tool in coronary artery disease since a decade ago the clinical usefulness of stress echocardiography has been demonstrated. For stress echocardiography a semisupine bicycle position for continuous recording of echocardiographic images from the apical position in the two-chamber- and RAO-view was developed. Echocardiographic images were digitized with a frame rate of 30/s and stored on optical discs with a storage capacity of 1 Gbyte. Rest and exercise images were analysed simultaneously for newly-occurring wall motion abnormalities or deterioration of already present hypokinesia or extension of existing wall motion abnormalities. Segmental wall motion was scored according to the scheme in Figure 2. In addition end-diastolic, end-systolic volume, and ejection fraction were calculated. In a patient population of 150, 30 female and 120 male, age 56.6 +/- 8.3 years, we could confirm the results reported by other working groups and demonstrate a high sensitivity in the diagnosis of single vessel disease. Our technique with the patient cycling in semi-supine position allows continuous echocardiographic registration during exercise and offers adequate image quality. The mean workload at peak stress was 127 +/- 30 watts, the maximal heart rate 137 +/- 18 bpm. Digital cine-loop imaging allowed evaluation of the examinations in about 90% of the cases. The sensitivity in the whole study group was 87%, the specificity 80%. Under full antianginal medication, 43% of the patients developed angina pectoris during exercise and 58% had a positive stress-ECG. The sensitivity in single-vessel coronary artery disease was 93% for the left anterior descending, 80% for the left circumflex, and 83% for the right coronary artery. These results in single-vessel disease were superior compared to findings of other authors using different techniques of stress echocardiography. In addition to the qualitative analysis, quantitative measurement of end-systolic volume and ejection fraction seems to be important. We found a significantly more pronounced decrease of ejection fraction at peak exercise in patients with multivessel disease compared to those with single-vessel disease. In single-vessel disease ejection fraction was 61 +/- 12% at rest and 57 +/- 17% during exercise, this difference was not significant.(ABSTRACT TRUNCATED AT 400 WORDS)

Cardiac Output↗