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Biomedical subjects

H Nolte

Publications and source records attributed to H Nolte.

At least 37 records · Page 2Linked to original sources
PubMed1997

Performance characteristics of a new automated enzyme immunoassay for the measurement of allergen-specific IgE. Summary of the probability outcomes comparing results of allergen skin testing to results obtained with the HYTEC system and CAP system.

BACKGROUND: Measurement of allergen-specific IgE may assist in the diagnosis of allergy in selected patients. The development of new assays for determination of allergen-specific IgE should be optimized with respect to analytical sensitivity, precision, automation, and reporting of test results in mass units. OBJECTIVE: The objectives of this study were to evaluate the analytical performance of the new automated HYTEC method for the measurement of allergen-specific IgE and to compare the performance of this new assay to that of the Pharmacia CAP system. METHODS: To demonstrate parallelism, allergen-specific IgE dilution curves were generated by diluting four patient sera containing cat (19.8 kU/L), D. pteronyssinus (5.4 kU/L), birch pollen (2.6 kU/L), and timothy grass (1.0 kU/L) with equine serum. The precision study utilized sera from three different atopic donors with low levels (0.62 +/- 0.05 kU/L), moderate levels (1.45 +/- 0.18 kU/L), and high levels (13.59 +/- 0.89 kU/L) of allergen-specific IgE to three common inhalant allergens: D. pteronyssinus, timothy grass, and birch. Sera for outcome probability determinations were obtained from 54 patients who were evaluated for the presence of inhalant allergy by skin prick test and physical examination. Only sera from patients with at least one positive skin prick test that clinically correlate with the physician's evaluation of case history and physical examination were selected for study material. In this study, sensitivity and specificity are conditional probabilities describing performances of the CAP system and the HYTEC system to skin prick testing. The lowest threshold, 0.35 kU/L, recommended for detection of allergen-specific IgE was used for both systems. RESULTS: The HYTEC system accurately detected a reduction in allergen-specific IgE antibody with different serum concentrations of allergen-specific IgE ranging from 0.10 kU/L to 20 kU/L. The median interdilutional coefficient of variation of 12.5% was obtained with assay samples containing 19.8 to 0.1 kU/L allergen-specific IgE antibody. During a 20-day trial period, three standard allergen-specific IgE controls, 0.62, 1.45 and 13.39 kU/L, respectively, demonstrated a mean coefficient of variation less than 18%. In 20% of the patients, duplicate assay determinations of allergen-specific IgE measurements resulted in a one-class discrepancy in the lowest assay range, 0.35 to 0.70 kU/L, only. The correlation coefficient between the HYTEC and CAP allergen-specific IgE assays was 0.77, rank correlation coefficients, being allergen-dependent and ranging from 0.62 to 0.91. Allergen-specific IgE assay sensitivity of the HYTEC system ranged from 0.78 to 1.00, whereas the assay sensitivity for the CAP system ranged from 0.50 to 1.00. Assay specificity ranged from 0.66 to 0.93 for the HYTEC system and from 0.70 to 0.87 for the CAP system. Eighty-nine percent of HYTEC-positive patients had a positive skin prick test (3% standard error) and 87% of CAP-positive patients had a positive skin prick test (4% standard error). Ninety-two percent of HYTEC-negative patients had a negative skin prick test (4% standard error), whereas 76% of CAP-negative patients had a negative skin prick test (5% standard error). CONCLUSION: The HYTEC system fulfills the current analytical requirements necessary to measure allergen-specific IgE antibody quantitatively and qualitatively, and compares favorably in performance with the CAP system.

Allergens↗
PubMed1997

The influence of age on the prevalence of hepatitis C virus subtypes 1a and 1b.

The distribution of hepatitis C virus (HCV) genotypes was determined in isolates of 447 chronically HCV-infected German patients by nucleotide sequencing. Of these, 206 (46.1%) were infected with the subtype 1a, 215 (48.1%) with subtype 1b, 2 (0.4%) with subtype 1c, 9 (2.0%) with subtype 3a, and 15 (3.4%) with subtype 4a. Subtype 1a was predominant in those < 40 years old (62.6%) and was associated with the risk factor of intravenous drug addiction and with shorter duration of disease. Conversely, subtype 1b was more frequent in patients > 50 years old (84.7%; P < .001) and was associated with the risk factor of blood transfusions and with longer duration of disease. These data suggest that a shift from subtype 1b to subtype 1a occurred in the population studied. An increase in HCV infection with subtype 1a and a diminution of subtype 1b in the future can be expected.

Adult↗
PubMed1996

[Ropivacaine for spinal anesthesia. A dose-finding study].

UNLABELLED: Several clinical studies have demonstrated the efficacy of ropivacaine in different regional anaesthesia techniques, e.g., epidural anaesthesia. However, the efficacy of ropivacaine for spinal anaesthesia has only been demonstrated in animal experiments up to now. The objective of this study was the investigation of the efficacy and appropriate dosage of isobaric ropivacaine for spinal anaesthesia in humans. METHODS: In a randomised, double-blind study, spinal anaesthesia with ropivacaine was performed in two groups of 20 patients each (group I: ropivacaine 0.5%, 3 ml = 15 mg; group II: ropivacaine 0.75%, 3 ml = 22.5 mg). Spinal anaesthesia was performed with a 25 G needle in the midline at the L3-4 level with the patient sitting up, preceded by local infiltration of 2 ml mepivacaine 0.5%. Spread and regression of sensory block were assessed by testing loss of sensation to cold. Development of motor block was concurrently recorded by means of a modified Bromage scale (motor block was assessed in the hip, knee and ankle joints and recorded as complete or incomplete according to degree). The findings are presented as mean values. RESULTS: Onset of analgesia to L5 and S1 was 2 min in both groups, and to T12 and T10 8 and 12.5 min, respectively, in group I and 12.5 and 13 min, respectively, in group II; these differences were not statistically significant. Mean maximum spread was to T10 in group I and T8 in group II. Onset of maximum cranial spread was 24 min in group I and 32 min in group II. Duration of analgesia in the segments relevant to the performed operations varied in group I between 1.5 and 5.7 h (S3 4.9, S1 5.7, L4 5.4, L2 3.0, T12 2.0, T10 1.6, T8 1.5 h) and in group II between 1.8 and 5.9 h (S3 5.4, S1 5.9, L4 5.7, L2 4.1, T12 2.9, T10 2.3, T8 1.8 h). These differences were significant in the segments S3, L3, L2, L1, T12, and T10. In 5 patients (20%) in group I adequate analgesia for the planned surgical intervention was not obtained. In 4 of these 5 patients the required spread of the spinal block was not reached; in 2 general anaesthesia had to be performed and in 2 the required analgesia could be obtained by administration of an analgesic (fentanyl). In the 5th patient the level of spinal block was sufficient for the planned operation, however, the quality of analgesia was not, i.e., additional analgesics were required. In the group that received the 0.75% solution additive analgesics were necessary in 1 patient (5%) because a sufficient level of anaesthesia for the planned operation was not obtained. In group I all patients had a complete motor block in all three joints (hip, knee, and ankle); in group II, however, the motor block was incomplete in 6 patients. This difference between the 2 groups was statistically significant. Onset of motor block of hip, knee, and ankle joints occurred after 10, 15, and 15 min, respectively, in group I and 10, 12 and 15 min, respectively, in group II. These differences were not statistically significant. Duration of motor block in the three joints was significantly longer (3.4, 2.8, and 3.8 h) in group II than in group I (2.4, 1.9, 2.7 h). Statistically significant changes in systolic and diastolic blood pressures (BP) and heart rate (HR) were recorded in both groups in the course of the study period. Relative BP changes were assessed in the individual patients. There were no statistically significant changes between the two groups with regard to relative changes in systolic and diastolic BP and HR. Bradycardia occurred a total of 13 times in 10 patients in group I and in 11 patients in group II. A BP decrease of > 20% was measured in 1 patient in each group. Twelve of the 40 patients complained a headache in the first 6 days; in this respect the groups did not differ significantly. There was no difference between male and female patients with regard to side effect profile. CONCLUSION: At concentrations of 0.5% and 0.75%, ropivacaine results in long-lasting spinal anaesthesia. (A

Amides↗
PubMed1996

Comparison of recombinant timothy grass pollen allergens with natural extract for diagnosis of grass pollen allergy in different populations.

BACKGROUND: Complementary DNAs coding for the major timothy grass pollen (Phleum pratense) allergens Phl p 1, Phl p 2, and Phl p 5 and birch profilin were isolated, expressed as recombinant nonfusion proteins in Escherichia coli, and purified. OBJECTIVE: In this study the in vitro IgE-binding capacity of recombinant Phl p 1, Phl p 2, Phl p 5, and birch profilin and their IgE recognition frequencies were investigated by using sera from different populations. METHODS: One hundred eighty-three sera from patients allergic to grass pollen were obtained from different populations in Europe, Japan, and Canada. The sera were selected according to clinical criteria, skin testing, and RAST (CAP system; Pharmacia, Uppsala, Sweden) and then tested for IgE reactivity with natural and purified recombinant timothy grass pollen allergens by ELISA and Western blot. RESULTS: Most (94.5%) of the patients allergic to grass pollen could be diagnosed with a combination of recombinant Phl p 1, Phl p 2, Phl p 5, and profilin by means of ELISA. Sera that did not react with the recombinant allergens contained low levels of timothy grass pollen-specific IgE. Although considerable variability in IgE recognition frequency of the recombinant allergens was observed in certain populations, a good correlation was found between natural timothy CAP results and the combination of recombinant allergens in all 183 tested sera (r = 0.87). CONCLUSIONS: Despite considerable variability in the IgE recognition frequency, purified recombinant timothy grass pollen allergens (Phl p 1, Phl p 2, Phl p 5) and profilin permitted successful in vitro diagnosis of grass pollen allergy in 94.5% of allergic individuals from different populations. The addition of other recombinant allergens (e.g., recombinant Phl p 4) would only slightly improve the in vitro test sensitivity.

Allergens↗
PubMed1993

Cutaneous histamine reactivity, histamine content of commercial allergens, and potential for false-positive skin test reactions in dogs.

The cutaneous reactivity of normal and atopic dogs to intradermal injections of histamine phosphate was evaluated. Significant differences were not found in the mean wheal diameters of either group. Commercial allergens used for intradermal skin testing and immunotherapy were determined to contain histamine. To determine whether allergen histamine content was sufficient to cause false-positive skin test results, the cutaneous response of Johnson grass allergic dogs was compared, using commercial Johnson grass allergen and commercial Johnson grass allergen with histamine removed. Significant differences were not noticed between Johnson grass and dehistaminized Johnson grass. Therefore, the histamine content of commercial Johnson grass allergen did not appear to cause false-positive skin test results for this group of Johnson grass allergic dogs.

Allergens↗
PubMed1993

Comparison of fiberglass-based histamine assay with a conventional automated fluorometric histamine assay, case history, skin prick test, and specific serum IgE in patients with milk and egg allergic reactions.

A microfiberglass-based histamine assay (HRM) was compared with an automated fluorometric histamine assay (HRA). Twenty-four subjects with and 24 without a case history (CH) of milk and/or egg allergy were tested by HRM and HRA, skin prick test (SPT), and specific serum IgE (RAST). Six different concentrations of milk, egg, and anti-IgE were used to stimulate washed leukocytes (250 microliters for HRA) and whole blood samples (25 microliters for HRM) in parallel. When we compared scores representing basophil sensitivity, correlation coefficients (rs) were positive (r(anti-IgE) = 0.88, r(egg) = 0.95, r(milk) = 0.88, P < 0.001), but no significant correlations were found after exclusion of the negatives in both tests. In some individual dose-response curves, the scores obtained by HRM were shifted to higher allergen and anti-IgE concentrations. A high degree of concordance was found in positive and negative responses between the two tests: anti-IgE 91%, egg 92%, milk 86%. Finally, we found a good concordance between, on one side, HRM and, on the other, CH, SPT, and RAST (HRM vs. CH/SPT/RAST): egg 92/82/82%; milk 89/74/67%. We conclude that HRM is in good qualitative, but poor quantitative, agreement with the autoanalyzer-based fluorometric histamine assay.

Adolescent↗
PubMed1993

[Prolongation and normalization of bleeding time during therapy with different doses of acetylsalicylic acid].

The present study investigated whether there is a statistically significant correlation between platelet aggregation inhibition (TAI) and prolongation of subaqueous bleeding time (SBT) under therapy with 40 mg (n = 20) and 500 mg (n = 20) acetylsalicylic acid (ASA) daily and when parameters return to normal after discontinuation of long-term (4 weeks) and short-term (1 week) treatment. The results of this study may be helpful in clinical practice when deciding upon indications for certain operative or anaesthetic procedures. RESULTS. Under ASA treatment, neither TAI nor prolongation of SBT was dependent on dosage or time (Figs. 1-4). After discontinuation of ASA, platelet aggregation returned to normal 1-4 days later than SBT, depending on the dosage and duration of medication. SBT declined to its initial value on the 3rd day following discontinuation of ASA in both dosage groups (Figs. 2 and 4). Normalisation of platelet aggregation depended on dosage: in those groups with 40 mg ASA, thrombocyte aggregation had normalised on the 4th day irrespective of duration of medication; in groups with 500 mg aggregation capacity was completely restored on the 5th day after 1-week therapy and on the 7th day after 4-week therapy (Figs. 1 and 3). Considering these results, an important factor is the time of discontinuation of ASA intake. Prior to scheduled operative procedures or regional anaesthetics near the spinal cord, ASA should be discontinued, depending on the dosage, 2-3 days ahead. At this time SBT has reached the initial value, however, the aggregation capacity of thrombocytes is still reduced for a few days.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Pneumatosis intestinalis--histology, immunocytochemistry and new theory of morphogenesis].

Based on the light microscopical and immunocytochemical findings in two cases of pneumatosis intestinalis, a new theory is advanced on the morphogenesis of the cysts that can be observed in this disease. The cavities identifiable in both cases in the submucosa of the small intestine and of the colon, respectively, were partially lined by histiocytes and foreign-body giant cells. Most of the lumina found in the subserosa of the stomach, small intestine and colon had an identical aspect. In addition, there were numerous true cysts here with a narrow, single-layered cells seam, showing the immunocytochemical characteristics of the mesothelium, but not the capillary endothelia. Thus, contrary to previous assumptions, pneumatosis interstinalis apparently does not develop from cystic dilatation of gas-filled lymph vessels that shrink and disappear in the process of an inflammatory foreign body reaction. Rather, the disease initially seems to manifest itself through gas-filled pseudocysts partially bordered by histiocytes and foreign-body giant cells, which become secondarily mesothelialized in the subserosa. Lymph vessels would thus not have significance for the morphogenesis of this disease.

Aged↗
PubMed1992

The histamine content of allergen extracts.

The histamine content of 108 inhalant, food, and venom extracts from four commercial sources was measured by chemical (glass fiber-based) and immunologic (competitive RIA) methods. Histamine was present in 64 of 76 inhalant extracts (range, 0.005 to 7.4 micrograms/ml), 20 of 26 food extracts (range, 0.16 to 23 micrograms/ml), and six of six venoms, 100 micrograms/ml (range, 1.0 to 38 micrograms/ml). Histamine was removed by treatment with diamine oxidase or dialysis of an extract. Repeat assay of selected extracts after addition of known amounts of histamine in the glass fiber-based method produced additive results, and glycerin- or phenol-extract preservatives did not affect assay performance. Timed extractions of dried-pollen grains demonstrated maximal histamine content at 30 seconds, suggesting that histamine is an inherent component of at least some pollens. Histamine found in some allergen extracts could, under extreme circumstances, produce false-positive results in skin testing and in basophil histamine release assays, and could affect the result of research that uses intact pollen or allergen extracts.

Allergens↗
PubMed1992

[Long-term medication with acetylsalicylic acid--a problem in regional anesthesia?].

In patients medicated with acetylsalicylic acid (ASA) and undergoing regional anaesthesia there is a risk of traumatically induced haematoma, particularly near the spinal cord. The increased bleeding tendency following aspirin administration is due to a change in thrombocyte aggregation caused by irreversible inhibition of prostaglandin synthesis. In order to assess the bleeding risk, it was investigated whether and how much subaqueous bleeding time (SBT) and aggregation inhibition (AGI) change under low-dose medication, and when these values return to normal after the end of administration. RESULTS. 1. SBT increased significantly with daily ASA medication of 100 mg or of 300 mg. However, only 4.5% of the values measured were within a pathologic range. After discontinuation of the medication SBT significantly dropped on the 2nd day, reaching the initial level on the 4th day at the latest. 2. AGI was significantly reduced, to 20% of the normal value. Depending on the dosage, the 100-mg group reached full aggregation capacity on the 4th day and the 300-mg group on the 7th day following discontinuation of medication. 3. AGI returned to normal 2-3 days later than SBT. CONCLUSIONS. 1. In the case of pathologically increased values (greater than 6 min), the determination of SBT may indicate an increased bleeding risk. 2. If SBT is within the normal range during or shortly after ASA administration, thrombocytic function is still disturbed. Whether there is a correlation between inhibition of thrombocyte aggregation and the occurrence of spinal haematomas is not yet known. 3. In view of these results, the effect of ASA should be investigated by determining SBT prior to scheduled regional anaesthetic procedures near the spinal cord. 4. If SBT is increased (greater than 6 min) and regional anaesthesia near the spinal cord is indicated, the procedure involving the slightest trauma (spinal anaesthesia) should be chosen [31]. Careful postoperative follow-up (1-2 days) should be guaranteed with regard to neurological disorders.

Adult↗
PubMed1992

[Determination of the spread of epidural anesthesia. A comparison between pin-prick and a new method using a metallic roller].

A new method (metal roller) for testing the spread of analgesia in regional anesthesia is introduced. The possible advantages of testing with a metal roller (cold sensation) in comparison to the pinprick method are investigated and discussed to determine whether loss of cold-sensation is comparable to loss of pinprick-sensation and thus reliable in clinical practice. METHOD AND MATERIAL. Spread of analgesia was tested with both the metallic roller and the conventional pinprick method in 40 patients (20 epidural and 20 spinal blocks), and pain perception or cold perception were compared. RESULTS. In epidural as well as in spinal anesthesia, similar levels of loss of pain perception and cold perception were found. DISCUSSION. Testing the spread of analgesia after nerve bock by the pinprick method is sometimes unpleasant for the patient. The metal roller is not unpleasant, and the possible danger of contamination or pinprick pain is virtually impossible because physical integrity is preserved and the feeling of "cold" is not harmful.

Anesthesia, Epidural↗
PubMed1992

[Does an injection filter modify the cranial spread of a sensory blockade in epidural anesthesia?].

UNLABELLED: In a prospective study we compared the spread of sensory blockade in epidural anaesthesia with and without Micropore filter. MATERIALS AND METHODS: A total of 32 patients undergoing varicose vein stripping under epidural anaesthesia were randomly assigned to two groups of 16 each. Bupivacaine 0.75% and POR 8 (0.1 IU/ml) were administered by means of a constant-velocity perfusor. In group A a Micropore filter was inserted between the perfusor syringe and the epidural catheter. In group B the epidural catheter was connected to the syringe without the filter. The puncture was performed at the L3-4 interspace with the patient in a sitting position. An epidural catheter was advanced 3 cm cephalad. Using the pin-prick method, the sensory level of the blockade was tested 5, 7, 10, 15, 20 and 30 min after injection of the local anesthetic solution. Statistical evaluation was performed with the t-test for unpaired samples. RESULTS. After 10 min the spread of analgesia was 5.75 +/- 1.26 segments in group A and 8 +/- 1.89 segments in group B; after 15 min it was 7.06 +/- 1.62 segments and 9.56 +/- 1.54 segments; after 20 min, 7.87 +/- 1.62 segments and 10.62 +/- 1.45 segments; and after 30 min 8.12 +/- 1.66 segments and 11.12 +/- 1.45 segments in group A and B, respectively. At any time sensory blockade was higher in group B (without Micropore filters) than in group A. The mean difference between the two groups amounted to 2-3 segments. The differences were significant at any time (P less than 0.001). These results show that the use of a Micropore filter in epidural anaesthesia leads to a reduced spread of sensory blockade. In our own examinations we found lowering of the pressure of the local anaesthetic solution that passes through the Micropore filter compared with the pressure of the solution injected without the filter. This seems to be the reason for the reduced spread of sensory blockade. Using these filters the onset of analgesia is delayed, and a given spread of analgesia needs a larger dose of local anaesthetic and is thus accompanied by a higher toxicity.

Adult↗
PubMed1992

[Subdural and epidural hematomas following epidural anesthesia. A literature review].

Of 434 cases of epidural, subdural, and intracranial haematomas published in the last 2-3 decades, 61 had developed following spinal, epidural or caudal anaesthetic procedures; 29 haematomas were around the spinal cord and 32, within the cranium. The most frequent secondary cause of this complication was pre-, intra-, or postoperative administration of drugs influencing blood coagulation. Simultaneous traumatic and haemorrhagic punctures may favour the development of a haematoma. The most common primary symptom of lumbothoracic haematomas was back pain with and without radicular symptoms, while intracranial haematomas were predominantly accompanied by persistent headache. Continuous postoperative follow-up of such patients is essential. Postoperative results of laminectomies for lumbothoracic haematomas has been found to on the time interval between the first symptoms and the start of surgery. If surgery is performed within 8 h after the onset of paraplegia the prognosis is relatively good. Compared with the frequency of spinal, epidural, and caudal anaesthetic procedures throughout the world, haematomas of the lumbothoracic or cranial region are extremely rare complications.

Adult↗
PubMed1991

Biochemical signal transduction of mechanical strain in osteoblast-like cells.

The responses to mechanical loading of two types of osteoblast-like cells and skin fibroblasts were investigated using two new devices for applying defined and homogeneous strains to cells. The results indicate that only periostal (bone surface) osteoblasts are sensitive to strains within the physiological range and that a specific strain mechanism is responsible. Osteoblasts derived from the haversian system and skin fibroblasts do not respond except at higher, unphysiological strains. The mechanism is located in the cytoskeleton and activates the membrane phospholipase C within milliseconds and may react to distension of a strain sensitive protein. Activation of phospholipase C can account for only some of the observed responses of bone to mechanical loading such as stimulation of cell division, increase in collagen and collagenase production. Application of over 10,000 mu strains results in a de-differentiation of the osteoblasts and a change in cell morphology to become fibroblast-like.

Animals↗