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H Mayer

Publications and source records attributed to H Mayer.

At least 127 records · Page 7Linked to original sources
PubMed1994

The structure of the O-specific polysaccharide of Salmonella arizonae O62.

The O-specific polysaccharide was liberated by mild acid hydrolysis of the lipopolysaccharide (LPS) isolated from S. arizonae O62 by phenol-water extraction. The branched hexasaccharide repeating-unit of the O-specific chain of the O62 LPS contained L-rhamnose, 2-acetamido-2-deoxy-D-glucose, and 2-acetamido-2-deoxy-D-galacturonic acid in molar ratios of 4:1:1. On the basis of methylation analysis, 1H and 13C NMR spectroscopy, including 2D shift-correlated (COSY) and 1D NOE spectroscopy, the following structure for the repeating unit of the O-specific polysaccharide was established: [formula: see text]

Carbohydrate Conformation↗
PubMed1994

Time-dependent effects of parathyroid hormone and prostaglandin E2 on DNA synthesis by periosteal cells from embryonic chick calvaria.

Both PGE2 and PTH (1-34) caused a time- and concentration-dependent stimulation of proliferation by embryonic chick periosteal cells. Cells were exposed to the agents for different periods of time, the medium was replaced with fresh medium, and 3H-TdR incorporation was measured after 16 hours. Challenge with 10(-6) M prostaglandin E2 (PGE2) or 10(-7) M parathyroid hormone (1-34) (PTH) for 5 minutes produced 4- and 5.5-fold increases in 3H-TdR incorporation, respectively. Longer exposures, however, produced diminishing responses and after 45 minutes, only minimal effects or slight inhibitions were seen. These time-dependent effects were also seen with forskolin and dibutyryl-cAMP; TPA on the other hand stimulated DNA synthesis after both short- and long-term exposure. Both PGE2 and PTH (1-34) stimulated cAMP synthesis in periosteal cells but neither could be shown to stimulate protein kinase-C (PKC) at concentrations required for stimulation of proliferation, and dibutyryl-cyclic AMP (cAMP) effectively inhibited endogenous PKC activity. It is possible that the stimulation of proliferation by short-term exposure to PGE2 and PTH (1-34) is mediated by cAMP and that the time dependency possibly stems from the inhibition of endogenous PKC activity by increased intracellular cAMP levels.

Animals↗
PubMed1994

Intravascular lymphomatosis: a clinicopathological study of three cases.

In patients with intravascular lymphomatosis (IL) a broad spectrum of neuro-psychiatric disorders including dementia, focal neurological signs and seizures has been reported. Clinical diagnosis is difficult since neuroimaging findings are nonspecific. The clinical histories, biopsy and autopsy findings of three patients with IL, one with brain biopsy, are described. Two of them presented with rapidly progressive, fluctuating dementia. The third patient suffered from seizures followed by aphasia. Histology revealed large-cell lymphoma of the B cell type. The prognosis of IL, in general, is poor.

Aged↗
PubMed1994

The influence of low growth temperature on the amount of free R lipopolysaccharide, on the expression of R-core determinants and on O-chain lengths in Salmonella S forms.

Ten Salmonella strains belonging to five serological groups were cultivated both at 37 degrees C and close to their individual temperature minima at 12-14 degrees C and the composition of their cell wall lipopolysaccharides (LPS) was compared. When grown at low temperature, the proportion of unsubstituted (free) R-LPS in the total LPS moiety increased significantly in 6 strains, whereas in the other strains, no change or even a slight decrease in the R-LPS proportion was observed as judged from the analyses by SDS-PAGE. In the immunoblot, the R-LPSs from 9 out of 10 strains showed a modified reactivity against a set of specific Salmonella R antisera (anti-Ra, anti-Rb1, anti-Rb2, anti-Rc). In most cases, the decrease in Rb1 reactivity was paralleled by an increase in Rb2 reactivity and also by an increase in the total amount of free R-LPS. The electrophoretic mobility of free R-LPS was changed in 7 out of 10 strains, although the changes were not unidirectional. All changes occurred only in the range of the Ra-Rb1 chemotypes and no significant correlation to the serological grouping of the strains was evident. When grown at low temperature, the average number of O-repeating units was reduced in the majority of cases and in some cases, also the banding profile in SDS-PAGE in the S-LPS region was modified. The fatty acid spectra showed some changes which were in accordance with previous results, namely a decrease in the content of C-12:0 and C-16:0 and an increase in that of C-14:0 and C-16:1. The different influences of the growth temperature on the LPS biosynthesis of different Salmonella strains may be a result of the genetic diversity of this group of microorganisms.

Electrophoresis, Polyacrylamide Gel↗
PubMed1994

Calibration problems of subcutaneous glucosensors when applied "in-situ" in man.

Continuous glucose monitoring is the conditio sine qua non to achieve total automation in glucose-controlled insulin-delivery. Several types of glucosensors have been designed according to the enzyme-amperometric method to measure the glucose in different human compartments. However, problems such as long-term stability and calibration prevent this technique being put into practice. A feasible method is needed to calibrate the glucosensor and at the same time should be accepted by the patients. To achieve calibration we determined the absolute tissue glucose, as well as the microdialysis recovery in-vivo, in healthy subjects under normal conditions and during a hyperglycaemic clamp by applying a device based on the recirculation of phosphate buffer saline in a microdialysis probe implanted in the s.c. adipose tissue. The first experiments carried out were promising and encouraging, but further investigations are still needed to favour an ideal "before implantation, all in-vitro" method to calibrate a s.c. glucosensor.

Biosensing Techniques↗
PubMed1994

[Clinical study of the effectiveness of a new preservative-free polyvidon preparation in therapy of dry-eye disorders].

BACKGROUND: Diseases of the ocular surface very frequently seen are related to irregularities of wetting. Patients often have complaints and feeling of ill-health, although under symptomatic therapy. Tolerability of the tear substitutes plays a key role in these cases. It is improved with unpreserved medication. METHOD: 59 patients with 'dry eye condition' of various etiology were enrolled in an open multicentre study and treated 8 weeks with a new preservative-free tear substitute. All patients had a history of previous ineffective treatment with artificial tears. The product was formulated with polyvidone and electrolytes in a composition which resembles natural tears. The therapeutic effect was evaluated by ratings of patients' self assessment of their complaints, tear film break up time (BUT), Schirmer I test, visual acuity, biomicroscopic examination and physicians' assessment. RESULTS: Based on the key criteria patients's self assessment and BUT, the new agent (Oculotect fluid sine) improved symptoms and reduced discomfort significantly compared with the previous treatment (paired t test, two-sided, level of significance p < or = 0.05). The improved condition was confirmed by the other findings taken. CONCLUSION: In 4/5 of patients, as typically met in ophthalmologists' offices, whose complaints were insufficiently relieved by previously applied tear substitutes, treatment with the new preservative-free product resulted in a distinct improvement of their condition. The lack of preservatives contributed to better tolerability and acceptance of tear substitution.

Adult↗
PubMed1994

Body-fat distribution and changes in the atherogenic risk-factor profile in obese adolescent girls during weight reduction.

We examined the effect of the pattern of body-fat distribution on the modification of atherogenic risk factors in obese adolescent girls during weight reduction. During the 6-wk program, which included a mixed diet of 4321 kJ/d and intensive physical exercise, the girls lost 8.5 +/- 2.4 kg and their waist-to-hip ratio (WHR) decreased from 0.86 +/- 0.05 to 0.81 +/- 0.05 (P < 0.01). Significant reductions were observed for total cholesterol, LDL cholesterol, uric acid, fasting insulin, and systolic and diastolic blood pressure. Girls with abdominal obesity (WHR > 0.88) had greater reductions in serum cholesterol, LDL cholesterol, and uric acid than did girls with gluteal-femoral obesity (WHR < 0.81). In a multivariate-regression analysis these differences could be partly explained by the greater weight loss of the girls with abdominal obesity. These results suggest that during weight reduction girls with abdominal obesity exhibit more beneficial changes in the atherogenic-risk-factor profile than do girls with gluteal-femoral obesity, partly because of a greater weight loss.

Adipose Tissue↗
PubMed1994

4-Amino-4-deoxy-L-arabinose in LPS of enterobacterial R-mutants and its possible role for their polymyxin reactivity.

The content of 4-amino-4-deoxy-L-arabinopyranose (L-Arap4N) and the phosphate substitution pattern of the LPS of various strains from Salmonella minnesota, Yersinia enterocolitica and Proteus mirabilis was determined by GC/MS, HPLC and 31P-NMR. These data allowed us to examine the possible role of these components for the polymyxin B-binding capacity of LPS and for the minimal inhibiting concentration (MIC) and the minimal bactericidal concentration (MBC) of polymyxins B and E towards the respective R-mutants. Contrary to other investigated Re-, Rd- and Rc-mutants of S. minnesota, strain R595 (Re-mutant) showed about a 90% substitution of the ester-linked phosphate-group with L-Arap4N, whereas the L-Arap4N content of the other S. minnesota strains amounted to 17-25%. Neither the binding capacity of LPS to polymyxin B, determined by a bioassay, nor the MIC- and MBC-values of the R-mutants were significantly affected by this alteration. Similar results were obtained after using the temperature-dependent changes in the L-Arap4N-content and phosphate substitution pattern of Y. enterocolitica 75R. In order to explore the relevant polymyxin B binding site, lipid A samples with or without substitution of their ester-linked phosphate group were prepared and subjected to the polymyxin-binding assay. The results obtained so far indicated that the inner core bound L-Arap4N, detected in all resistant strains investigated, may play a decisive role in the decreased binding of polymyxin B, responsible for the bacterial resistance towards polymyxin(s).

Amino Sugars↗
PubMed1994

Synergistic effects of parathyroid hormone and 1,25-dihydroxyvitamin D3 on proliferation and vitamin D receptor expression of rat growth cartilage cells.

We investigated possible interaction of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] and PTH on: 1) proliferation (monolayer culture) and colony formation (agarose stabilized suspension cultures); 2) expression of 1,25-(OH)2D3 receptor (VDR); and 3) cAMP response to PTH, using primary cultures of chondrocytes from rat tibia proximal epiphysis. 1 alpha,25-(OH)2D3 stereospecifically stimulated DNA synthesis, cell counts, and colony formation at low concentration (10(-12) M). Within 6 h bovine PTH (bPTH)(1-34), human PTH (hPTH)(28-48) (10(-10) M), (Bu)2cAMP (1-2 mM), and 12-O-tetradecanoyl-13-acetate (10(-8) M) increased [3H]thymidine incorporation in the absence and presence of 1,25-(OH)2D3. Both PTH fragments also stimulated chondrocyte growth and colony formation in a Ca-dependent fashion. Prolonged exposure to bPTH(1-34) or hPTH(28-48) did not affect baseline DNA synthesis but increased the stimulatory effect of 1,25-(OH)2D3. This increase was inhibited in the presence of H7 (inhibition of PKC) or the monoclonal hPTH(1-38) antibody A1-70. In subconfluent chondrocyte cultures VDR was up-regulated by bPTH(1-34) and hPTH(28-48) (10(-10) M) or activators of protein kinase C (PKC), but not by (Bu)2cAMP. It was blocked by cycloheximide and actinomycin D and persisted in the presence of Ca-channel blockers. Inhibition of PKC by H7 also blocked the effect of bPTH(1-34) on VDR. The cAMP response to bPTH(1-34) was not affected by 1,25-(OH)2D3. We conclude that: 1) DNA synthesis, cell proliferation, and colony formation in chondrocyte monolayer or suspension cultures is increased by aminoterminal and midregional PTH fragments and by cAMP analogs in a Ca- dependent fashion; 2) bPTH(1-34) and hPTH(28-48) up-regulate VDR by cAMP-independent, PKC-dependent steps requiring transcriptional and translational processes; both PTH fragments also amplify the effect of 1,25-(OH)2D3 on DNA synthesis; and 3) no difference is found between the bPTH(1-34) and hPTH(28-48) fragments with respect to chondrocyte proliferation and VDR up-regulation, although the two differ with respect to stimulation of cAMP production.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1994

[The concept of myocardial infarct rehabilitation in phase III].

The benefit of outpatient rehabilitation in coronary artery disease is well documented in literature. Despite this, there is evident lack of rehabilitation facilities during phase III WHO in our country. Departments of Physical Medicine and Rehabilitation seem to be well suited to run ambulant rehabilitation programmes. Therefore we developed a comprehensive rehabilitation programme including physical training, dietary counselling and teaching lessons for patients. Physical training is strictly aerobic according to the guidelines of medical training therapy. Training time will rise systematically. To keep risks low, precise in- and exclusion criteria are defined. Regular training for the staff is mandatory. Uniformity of therapeutic interventions and documentation provide quick evaluation of therapeutic success.

Ambulatory Care↗
PubMed1994

[Value of interventional procedures in treatment of stenotic and occluded infra-inguinal vascular bypasses].

In a prospective study, the results following PTA of 30 short stenoses > 70% in 17 infrainguinal arterial bypass grafts were examined. The stenoses were detected after a mean follow-up of 7.2 months by Duplex-ultrasound. The initial success rate after PTA was 100%. After an average time of 4.6 months recurrent graft stenoses were identified in 8 bypasses and 1 patient experienced graft thrombosis. Overall 8 of the 17 patients with stenotic grafts were treated by PTA alone during a mean follow-up of 11.7 months. Using life-table analysis, primary and assisted primary patency rates were each 100% at 1 month and 41 and 86% at 2 years. The efficacy of thrombolysis in 36 occluded grafts (graft age > 30 days) with clinical symptoms of incomplete ischaemia was analyzed retrospectively. After successful lysis in 61% (22/36), 15 grafts underwent additional procedures including PTA (10), vein patch angioplasty (4) and distal graft extension (1). Following successful initial graft salvage, primary cumulative patency and limb salvage rates were 45 and 72% at 1 month and 16 and 51% at 3 years. PTA of primary graft stenoses may be regarded as an acceptable initial therapeutic option, but has some limitations in providing sustained patency. Grafts initially salvaged with lysis do not have favourable short and long-term patency.

Aged↗
PubMed1993

Influence of the supramolecular structure of free lipid A on its biological activity.

The three-dimensional supramolecular structures and the states of order of the acyl chains of lipid A from different Gram-negative species were investigated at 40 degrees C, high water content (80-90%), and different [lipid A]/[Mg2+] molar ratios using synchrotron radiation X-ray diffraction and Fourier-transform infrared spectroscopy. Measurements were made on free lipid A from Salmonella minnesota R595, mono- and bi-phosphoryl, as well as those from the non-enterobacterial strains Rhodobacter capsulatus 37b4, Rhodopseudomonas viridis F, and Rhodocyclus gelatinosus 29/1. Parallel to differences in their chemical primary structure, the structural polymorphisms and states of order at 37 degrees C of the non-enterobacterial lipid A were found to be different from those of enterobacterial lipid A. A clear correlation between the supramolecular structure and previously determined biological activities was found. Lipid A with a strong preference for lamellar structures (Rb. capsulatus and Rp. viridis) are endotoxically inactive and lack cytokine-inducing capacity; the compounds assuming a mixed lamellar/nonlamellar structure (monophosphoryl lipid A from S. minnesota) are of lower toxicity in vivo, but may induce cytokines in vitro; those lipid A with a strong tendency to form non-lamellar inverted structures (lipid A from S. minnesota and Rc. gelatinosus) exhibit full endotoxicity in vitro and in vivo. In contrast, anti-complementary activity is most pronounced for compounds with lamellar and least expressed for those with inverted structures. The states of order at 37 degrees C vary non-systematically, exhibiting the highest values for lipid A of S. minnesota and the lowest for that of Rc. gelatinosus. We propose to extend the term 'endotoxic conformation', which is used to describe the conformation of a single lipid A molecule required for optimal triggering of biological effects, to 'endotoxic supramolecular conformation' which denotes the particular organization of lipid A aggregates in physiological fluids causing biological activity.

Carbohydrate Sequence↗
PubMed1993

Urban bioclimatology.

This article deals with the part of urban climatology which is of particular relevance to human beings. Presented first is a summary of all human biometerologically effective complexes, as well as other factors which are relevant to urban planning and which depend on atmospheric conditions in urban structures in a direct or indirect manner. Later, methods for human biometerologically significant assessment of thermal and air pollution components of the urban climate are discussed in detail, because these components can be strongly influenced by urban planning. The application of these methods is illustrated by some results of appropriate investigations in urban areas.

Climate↗
PubMed1993

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Journal Article↗
PubMed1993

Prognostic significance of myeloid-associated antigen expression on blast cells in children with acute lymphoblastic leukemia. The Austrian Pediatric Oncology Group.

The prognostic significance of expression of myeloid-associated antigens in childhood acute lymphoblastic leukemia (myA+ALL) was evaluated. From 1984 to 1990, 251 children with immunologically verified ALL were treated in two prospective consecutive Austrian studies. Complete immunophenotyping was performed in 206 cases (82%). Out of these 175 cases were classified as B-cell precursor ALL, 31 cases as T-ALL. Expression of myeloid-associated antigens was demonstrated in 23 cases (13.1%) of childhood B-cell precursor ALL, particularly in immature (CD10 negative) forms (P < .0001), and in 1 case (3.2%) of T-ALL. CDw65 was expressed most frequently (12 cases), followed by CD13 and CD15 (5 cases each), CD33 (4 cases), and blood-group H (3 cases). Compared to myA- ALL prognosis of children with myA+ B-cell precursor ALL was poor, despite intensive multiagent chemotherapy according to BFM protocols. Remission rates were not impaired, but pEFS was 74.6% for myA- ALL, and only 37.8% for myA+ ALL (P = .0001). As demonstrated by multivariate analysis the expression of myeloid-associated antigens was the most important prognostic variable for EFS in B-cell precursor ALL, whether or not CD10 was expressed.

Adolescent↗
PubMed1993

Distal vein graft reconstruction for isolated tibioperoneal vessel occlusive disease in diabetics with critical foot ischaemia--does it work?

Since 1986, 75 distal vein bypass procedures have been performed in 72 diabetics with isolated tibioperoneal vessel occlusive disease for limb salvage. Fifty-six grafts were anastomosed proximally to the below-knee popliteal artery and 19 to the anterior tibial artery. Autologous vein was used in all patients. One patient died within the first postoperative month. Of the occluded grafts, only two which failed during hospitalisation were salvaged. In six patients progressive plantar gangrene necessitated below-knee amputation in spite of graft patency. Using life-table analysis, primary and secondary patency rates were 84 and 86% at 1 year and 71 and 76% at 5 years. One- and five-year limb salvage rates were 81 and 72%, respectively. Distal vein graft reconstruction for limb threatening ischaemia produces excellent patency rates and contributes significantly to limb salvage in these patients.

Aged↗