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Biomedical subjects

M Beck

Publications and source records attributed to M Beck.

At least 181 records · Page 10Linked to original sources
PubMed1996

Anesthetic efficacy of the intraosseous injection after an inferior alveolar nerve block.

The purpose of this study was to determine the contribution of the intraosseous (IO) injection to the inferior alveolar nerve (IAN) block in human first molars. Using a repeated-measures design, 40 subjects randomly received either a combination IAN block + IO injection (on the distal of the first molar) using 2% lidocaine with 1:100,000 epinephrine or an IAN block+mock IO injection (gingival penetration only) at two successive appointments. The first molar and adjacent teeth, and contralateral canine (+/-controls) were blindly tested with an Analytic Technology pulp tester at 2-min cycles for 60 min. An 80 reading was used as the criterion for pulpal anesthesia. One hundred percent of the subjects had lip numbness with the IAN block. For the first molar, anesthetic success, defined as achieving an 80 reading within 15 min and keeping this reading for 60 min, was 42% with the IAN and 90% with the IAN + IO. Anesthetic failure defined as never achieving two 80 readings during the 60 min was 32% with the IAN and 0% with the IAN + IO. The onset of anesthesia was immediate with the IO injection. Eighty percent of the subjects sampled had a subjective increase in heart rate with the IO injection. The IO injection and postinjection questionnaire recorded low pain ratings.

Adolescent↗
PubMed1996

Anesthetic efficacy of the periodontal ligament injection after an inferior alveolar nerve block.

The purpose of this study was to determine the contribution of the periodontal ligament injection (PDL) to the inferior aveolar nerve (IAN) block in human first molars. Using a repeated-measures design, 40 subjects randomly received a combination IAN block and PDL injections of the first molar using 2% lidocaine with 1:100,000 epinephrine and a combination IAN block and mock PDL injections (needle penetration only) at two successive appointments. The first molar and adjacent teeth, and contralateral canine (positive and negative controls) were blindly tested with an Analytic Technology pulp tester at 2-min cycles for 60 min. Profound anesthesia was defined as no subject response at an 80 reading. One hundred percent of the subjects had lip numbness with the IAN block. When the combination IAN/PDL injections were compared with the IAN block, the incidence of successful pulpal anesthesia (80 reading) was significantly greater for the combination injections through the first 23 min of pulp testing. However, after 23 min, there was no increase in anesthetic success by adding the PDL to the IAN injection. We concluded that adding the PDL injection to an IAN block increased the incidence of pulpal anesthesia for the first 23 min in the first molar.

Adult↗
PubMed1996

Cephalometric A point changes during and after maxillary protraction and expansion.

The purpose of this study was to analyze the treatment and posttreatment maxillary changes achieved with maxillary protraction therapy. The cephalometric records of 25 consecutively treated Chinese children with Class III malocclusions (mean age 8.4 years) were analyzed for cephalometric A point changes, which were then compared with an untreated, age and sex matched Class III control sample. A cephalometric maxillary superimposition technique was used to differentiate between the skeletal and the local contributions to the total A point change. Results showed that 6 months of maxillary protraction therapy produced a mean A point advancement of 2.4 mm compared with 0.2 mm in the control group. Of this advancement, 75% was found to be due to skeletal maxillary advancement and 25% was attributed to local remodeling. Significantly less downward movement of A point was found with treatment compared with the controls, which could be related to the direction of force application. No significant differences were found in the horizontal and the vertical movements of A point between the treatment and the control groups during the 12-month posttreatment period, indicating stability of early maxillary protraction in patients with Class III malocclusions.

Case-Control Studies↗
PubMed1996

Anesthetic efficacy of the intraosseous injection in maxillary and mandibular teeth.

OBJECTIVE: The objective of this study was to determine the anesthetic efficacy of the intraosseous injection as a primary technique in human maxillary and mandibular teeth. STUDY DESIGN: Forty subjects received two sets of intraosseous injections with 1.8 ml of 2% lidocaine with 1:100,000 epinephrine at two successive appointments. The experimental teeth consisted of 40 groups of maxillary and mandibular first molars and lateral incisors. Each experimental tooth and adjacent teeth were tested with an electric pulp tester at 4-minute cycles for 60 minutes. Anesthetic success was defined as no subject response to the maximum output of the pulp tester (80 reading) for two consecutive readings. RESULTS: Anesthetic success occurred in 75% of mandibular first molars, in 93% of maxillary first molars, in 78% of mandibular lateral incisors, and in 90% of maxillary lateral incisors. Overall, for the intraosseous injection onset was immediate, the duration of pulpal anesthesia steadily declined over the 60 minutes, there was a 78% incidence of subjective increase in heart rate, the majority of the subjects had no pain or mild pain with perforation and solution deposition, and 3% of the subjects had slow healing perforation sites. CONCLUSIONS: The results of this study indicate that the intraosseous injection may provide pulpal anesthesia in 75% to 93% of noninflamed teeth as a primary technique. However, the duration of pulpal anesthesia declines steadily over an hour.

Adult↗
PubMed1996

Production of ouabain by rat adrenocortical cells.

Our aim was to identify which adrenocortical cells produce ouabain and how it is regulated in vitro. With the help of an ouabain radioimmunoassay developed in our laboratory, we found that ouabain is produced both by zona glomerulosa and fasciculata cells. Our results were confirmed by reverse-phase HPLC. ACTH increased ouabain production in both cell types. Angiotensin-II, as well as changes in the potassium concentration of the incubation medium, affected ouabain production only in the zona glomerulosa.

Adrenal Cortex↗
PubMed1996

Multiple alleles encoding a virus-like particle protein in the ichneumonid endoparasitoid Venturia canescens.

Hymenopteran endoparasitoids produce nuclear secretions from ovarian glands, which are deposited into the host insect together with the egg, protecting the developing parasitoid against the host's defence reactions. In the ichneumonid Venturia canescens, virus-like particles (VLPs), are attached to the egg surface and provide passive protection against encapsulation by the host. One of the four major particle proteins (p40) is expressed not only in the calyx gland but also in tissues that are not involved in particle production. The p40 coding DNA from V. canescens was cloned and sequenced. Within the coding DNA a tandem repeat sequence, coding for a putative proteolytic cleavage site of the PEST type, is rearranged in a significant portion of the wasp population. A corresponding polymorphism was also detected in the protein. The amino-terminal region of the deduced protein contains a putative type II transmembrane domain. The carboxy-terminal region shows similarity to the phospholipid hydroxyperoxide glutathione peroxidase (PHGPX) of vertebrates. A peroxidase function of the p40, although not ruled out, is unlikely due to the absence of a reactive centre which is typical for many vertebrate peroxidases. The overall conservation of the hydropathic region is discussed in the context of the formation of the viral envelope and its possible function in the immune protection.

Alleles↗
PubMed1996

[Typing of the apx toxin gene of Actinobacillus pleuropneumoniae using PCR].

For the determination of the apx toxin genes in Actinobacillus pleuropneumoniae strains, five PCR reactions were developed which allow the detection of the activator and structural genes and the secretion genes of the toxins ApxI, ApxII and ApxIII. The oligonucleotide primers were chosen in order to amplify characteristic parts of the activator and structural genes apxICA, apxIICA and apxIIICA, and the secretion genes apxIBD and apxIIIBD. The annealing temperature of all five reaction was identical in order to allow the five reactions in a single PCR run. The differences in length between the individual amplified gene fragments allowed all product fragments to be separated in a single electrophoresis. This way, a typical toxin gene pattern could be obtained which is characteristic for the five toxin gene groups of A. pleuropneumoniae including serotypes 1, 5a, 5b, 9 and 11 (group 1), serotypes 2, 4, 6 and 8 (group 2), serotype 3 (group 3), serotypes 7 and 12 (group 4), and serotype 10 (group 5). The identification of the toxin genes, which have significance in virulence, enhance and facilitate differentiation of A. pleuropneumoniae and allow the detection of serotypes with an atypical toxin pattern.

Actinobacillus pleuropneumoniae↗
PubMed1996

Mucopolysaccharidosis type II (Hunter syndrome): mutation "hot spots" in the iduronate-2-sulfatase gene.

Mucopolysaccharidosis type II (MPS II, Hunter syndrome) is an X-chromosomal storage disorder due to deficiency of the lysosomal enzyme iduronate-2-sulfatase (IDS). We have identified IDS mutations in a total of 31 families/patients with MPS II, of which 20 are novel and unique and a further 1 is novel but has been found in 3 unrelated patients. One of the mutations detected is of special interest as an AG-->G substitution in an intron, far apart from the coding region, is deleterious by creating a new 5'-splice-donor site that results in the inclusion of a 78-bp intronic sequence. While the distribution of gene rearrangements (deletions, insertions, and duplications) of <20 bp seems to be random over the IDS gene, the analysis of a total of 101 point mutations lying within the coding region shows that they tend to be more frequent in exons III, VIII, and IX. Forty-seven percent of the point mutations are at CpG dinucleotides, of which G:C-to-A:T transitions constitute nearly 80%. Almost all recurrent point mutations involve CpG sites. Analysis of a collective of 50 families studied in our laboratory, to date, revealed that mutations occur more frequently in male meioses (estimated male-to-female ratio between 3.76 and 6.3).

Alternative Splicing↗
PubMed1995

Mitral and aortic regurgitation in 84 patients with mucopolysaccharidoses.

UNLABELLED: In echocardiographic and necropsy studies nodular thickening of the mitral valve and, less frequently, of the aortic valve has been found in 60%-90% of patients with mucopolysaccharidoses (MPS). Little is known about the haemodynamic consequences of these morphological changes. In this study 84 unselected patients with different enzymatically proven MPS and 84 age and sex matched, healthy persons were studied prospectively by colour Doppler flow mapping. The patients' age ranged from 1 to 47 years (median 8.1 years). Mitral and aortic regurgitation were defined as a holosystolic or holodiastolic jet originating from the valve into the left atrium or the left ventricular outflow tract, respectively, with peak velocities exceeding 2.5 m/s. Of the 84 patients with satisfactory studies, mitral regurgitation was detected in 64.3% and aortic regurgitation in 40.5%, respectively. Regurgitation was severe in 4.8% of mitral valves and 8.3% of aortic valves. The frequency of aortic and/or mitral regurgitation was 75% in all patients, 89% in MPS I, 94% in MPS II, 66% in MPS III, 33% in MPS IV, and 100% in MPS VI. Combined mitral and aortic regurgitation was present in 29% of our patients. None of the control persons showed mitral or aortic regurgitation. CONCLUSION: Aortic and mitral regurgitation are more frequent in patients with MPS than previously thought and that therefore these patients should have regular colour Doppler flow mapping and antibiotic prophylaxis when required.

Adolescent↗
PubMed1995

Reactions to other corticosteroids in patients with positive patch test reactions to budesonide.

BACKGROUND: Corticosteroid cross-reactions have been classified into four well-defined groups. A previous study of patch test reactions to other corticosteroids in patients allergic to hydrocortisone failed to conform to these groups. It was suggested that substitution at the C6 and C9 positions of the corticosteroid was the most important determinant of a further reaction. OBJECTIVE: Our aim was to analyze multiple positive patch tests to corticosteroids in patients sensitized to budesonide to confirm our earlier findings. METHODS: Forty-six patients with positive patch tests to budesonide were patch-tested to 17 other topical corticosteroids. The results were examined by a generalized linear model and a chi-square test. RESULTS: Substitution of the corticosteroid at the C6 and C9 positions significantly reduced the number of reactions. A different substitution at the C16 and C17 positions was less important, and that at the C21 position was of no significance. CONCLUSIONS: Patients sensitized to budesonide are most likely to react to other non-C6 and non-C9 substituted corticosteroids.

Adrenal Cortex Hormones↗
PubMed1995

Development of an efficient PCR method for toxin typing of Actinobacillus pleuropneumoniae strains.

A method has been developed which allows the determination of the activator, the structural and the secretion genes of the three toxins ApxI, ApxII and ApxIII in Actinobacillus pleuropneumoniae in only two PCR reactions. The oligonucleotide primers were designed to amplify a significant part of the activator and structural genes apxICA, apxIICA and apxIIICA together in a single PCR reaction giving amplification products which differ in length, in order to be clearly separated by agarose gel electrophoresis. Variations in the apxIA and apxIIIA genes which were found in different serotypes were taken into account in the design of the primers to give a uniform amplification product for both variants of the apxIA and the apxIIIA genes. The secretion genes apxIBD and apxIIIBD are also detected in a single PCR reaction containing two pairs of oligonucleotide primers which yield two differently sized fragments to differentiate between apxIBD and apxIIIBD genes. The reference strains of A. pleuropneumoniae serotypes 1-12 and 104 field strains representing all serotypes obtained from various laboratories worldwide were analysed for their content of apx genes. The two PCR reactions give toxin gene patterns which are characteristic for different groups of serotypes in A. pleuropneumoniae and allow the rapid differentiation of five toxin type groups, group 1 including serotypes 1, 5a, 5b, 9 and 11, group 2 including serotypes 2, 4, 6, 8, group 3 with serotype 3, group 4 with serotype 7 and 12 and group 5 with serotype 10. The method enhances and facilitates differentiation of A. pleuropneumoniae strains for diagnostics and epidemiology and allows the detection of serotypes with atypical toxin patterns.

Actinobacillus pleuropneumoniae↗
PubMed1995

Histopathologic effects of kinetic cavity preparation for the removal of enamel and dentin. An in vivo animal study.

Recent developments in technology, direct placement restorative materials, and cavity preparation design have renewed interest in kinetic cavity preparation, a term to describe the use of air-abrasion for removal of tooth structure. This study compared the pulpal response of 120 teeth in mixed-breed dogs treated with four kinetic cavity preparation combinations of pressure (80 psi and 160 psi) and aluminum oxide particle sizes (27 microns and 50 microns) to those treated with high-speed rotary burs. Class V buccal preparations were made and restored with an interim material. Teeth were collected 72 hours after surgery, decalcified, sectioned, stained with hematoxylin and eosin, and blindly evaluated by two examiners at the minimal dentin thickness. Samples were graded for extent of displacement, disruption, inflammation, and necrosis of pulpal structures. Differences between groups were analyzed with the use of Bonferroni-adjusted multiple Mann-Whitney-Wilcoxon tests with p < 0.05 being significant. Higher pressures and smaller particles yielded significantly fewer pulpal effects than the high-speed treated teeth whereas lower pressures and larger particles were not significantly different for most effects evaluated. No adverse soft tissue effects were noted when kinetic cavity preparation was directed at attached gingiva.

Air Pressure↗