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Biomedical subjects

A Wenzel

Publications and source records attributed to A Wenzel.

At least 127 records · Page 7Linked to original sources
PubMed1987

Effect of varying gray-scale resolution for detectability of bone lesions in intraoral radiographs digitized for teletransmission.

Visual communication equipments were developed early by radiologists for the transmission of analog signals, whereas today's transmission systems are based on digitization of the radiograph. For teletransmission of dental radiographs, it is essential to assess the diagnostic accuracy of various spatial and gray-scale resolutions. Each of 83 dry mandibles was divided into four regions. By random assignment it was decided for each region whether or not a hole should be drilled. Intraoral radiographs (3 x 4 cm) were performed of each region and interpreted. The radiographs were thereafter recorded by a video camera connected to an IBM-PC. The personal computer held a hardware digitization card defined at a 512 x 512 spatial resolution with the possibility of selecting varying gray-scale resolutions. All radiographs were assessed in resolutions with 256 (8 bit), 128 (7 bit), 64 (6 bit), and 32 (5 bit) shades of gray. In no case was the original radiograph more accurate than the 512 x 512 x 8 resolution. In two of the regions evaluated, the images providing 32 shades of gray were less accurate (percentage of true positives and negatives) than the other resolutions (P less than 0.05) while in one region resolutions of 8 bit depth (256 shades of gray) provided a significantly greater accuracy than did the original radiograph and the other image resolutions (P less than 0.05). This was due to fewer false negative scores and was not followed by an increase in false positive scores. It can be concluded that a 512 x 512 spatial resolution is satisfactory for the detection of bone lesions in digitized intraoral radiographs and that 64 shades of gray provide an equally good diagnostic accuracy as do the original radiograph. This might be relevant when transmission times are of importance.

Animals↗
PubMed1985

Intermittent claudication: a double-blind crossover trial of pentoxifylline.

The influence of the xanthine derivative pentoxifylline ('Trental' or BL191; Hoechst-Roussel) on exercise tolerance was measured in 38 subjects with stable, severe to moderately severe, intermittent claudication who completed a randomised, double-blind, placebo controlled, cross-over clinical trial. Patients received placebo tablets or 400 mg slow-release pentoxifylline tablets ('Trental 400') twice a day for one week, followed by three times daily for seven weeks, and then crossed over to receive the alternate preparation for another eight weeks. Claudication distance and walking distance were measured on a treadmill before starting treatment and again at four-week intervals during the trial. At the same times, red blood cell filterability, plasma fibrinogen concentration and blood viscosity, resting and post-ischemic calf muscle blood flow, and the resting and post-exercise ankle/brachial systolic pressure ratio were also measured. In this study, the observed effects of pentoxifylline treatment were no greater than those of placebo, even though serum levels of pentoxifylline and its hydroxy-metabolite were within the anticipated range. This was shown by a 'therapeutic effect ratio' of 0.98 for treadmill claudication distance and 0.96 for treadmill walking distance after within-patient analysis at the end of the cross-over (where a ratio of 1.0 means the test drug and placebo effects are identical). These ratios have 95% confidence limits of 0.72-1.34 and 0.74-1.25, respectively.

Aged↗
PubMed1985

Syntheses and biological activities of new penem derivatives with side chains derived from 4-hydroxyproline.

New penem derivatives with various substituted, enantiomerically pure pyrrolidine-thio side chains at the C-2 position were synthesized and their chemotherapeutic potentials assessed in comparison with Sch 29482. The following criteria were used for preliminary evaluation: Antibacterial activity in vitro, beta-lactamase inhibition and apparent hydrolysis rates by crude murine and human kidney enzyme preparations. The most active compounds, 16e, 16f and 18 exhibit properties typical of this substance class with a tendency towards greater antibacterial potency in comparison with Sch 29482, especially against Pseudomonas aeruginosa. No clear-cut structure-activity relationships could be found with respect to beta-lactamase inhibition and stability against degrading renal enzymes.

Anti-Bacterial Agents↗
PubMed1984

Radiologic assessment of bone maturity and cortical thickness in experimental osteo-fluorosis in the young pig.

Radiographs of the left forelimb were obtained after slaughter in 16 14-month-old pigs. From age 8-14 months, eight pigs in the experimental group received 2 mg F-/kg body weight per day. Bone maturity in F-animals was the same as in controls. Cortical thickness was increased by 10 per cent in the fluorotic animals (p less than 0.01) and their plasma-fluoride levels increased throughout the experimental period to approximate those reported for man in endemic fluorosis areas. Thus fluoride given in the dose used and over that period, did not affect maturation in the long bones but increased cortical bone mass in the diaphyses.

Animals↗
PubMed1984

Dental health status and attitudes to dental care in families participating in a Danish fluoride tablet program.

The caries experience and dental fluorosis of 84 Danish children, who had used fluoride tablets for 1-4 yr in the period 1976-80, were compared with those of a group matching in sex, age, place of living, and socioeconomic status. The average age of the children at the time of examination was 5.8 yr. A recording of mothers' attitudes to dental care, knowledge about tooth brushing, attitudes to candy, and number of teeth in the maxilla showed no difference between the fluoride tablet group and the non-users' group. Moreover, there was no significant difference between the two groups with respect to dental caries. The findings are discussed in relation to recent reports on the decline of dental caries resulting from widespread use of local administration of fluorides.

Adult↗
PubMed1984

Effect of an intranasally administered corticosteroid (budesonide) on nasal obstruction, mouth breathing, and asthma.

The effect of intranasally administered corticosteroid (budesonide) on nasal symptoms, mode of respiration (nasal versus mouth breathing), and asthma was investigated in 37 asthmatic children who were mouth breathers because of chronic nasal obstruction. After a 2-wk run-in period, the children were allocated randomly to 4 wk of intranasal therapy with either budesonide (400 micrograms/day) or placebo spray. A double-blind, parallel design was used. Diaries for peak expiratory flow, asthma, and rhinitis symptom scores and degree of mouth breathing were recorded at home. Nasal eosinophilia, nasal airway resistance at a flow of 0.2 L/s (NAR0.2), and lung function at rest and after exercise challenge were assessed at the clinic immediately before and at end of the 4-wk treatment. Budesonide, when compared with placebo, significantly decreased nasal obstruction (p less than 0.05), secretion (p less than 0.01), and eosinophilia (p less than 0.02), as well as NAR0.2 (p less than 0.05) and mouth breathing (p less than 0.01). The improvement in nasal obstruction correlated closely to the changes in mouth breathing (r = 0.80, n = 17, p less than 0.001). Furthermore, intranasally administered budesonide resulted in less exercise-induced asthma (EIA) (p less than 0.02) and decreased cough and asthma severity significantly. Pulmonary mechanics were only marginally improved. The present study showed that intranasally administered budesonide is effective in the treatment of perennial allergic rhinitis. An attenuation of EIA and a tendency to less asthma after budesonide therapy suggest a decrease in bronchial reactivity, but the results gave no clear evidence of an association between nasal airway function and asthma.

Administration, Intranasal↗