Biomedical subjects
Publications and source records attributed to A Vogel.
A case of a 10-year old boy suffering from asthma bronchiale following pleuropneumonia is reported. Paradoxically, bronchospasmolysis tests using physiological saline + salbutamol or ipratropium bromide impaired the lung function of this patient. Salt solutions inhaled in increasing doses until 1.4% generated severe bronchoconstriction, however, inhalation of DNCG + salbutamol normalized the lung function completely.
The spectral dependence of the optical properties of human sclera adjacent to the limbus was investigated and related to the potentials of transscleral photocoagulation. The total transmission, absorption and reflection and the angular distribution of the transmitted and reflected light were measured at five laser wavelengths (442 nm, 514 nm, 633 nm, 804 nm, and 1064 nm) for both noncontact and contact applications. The scleral transmission is only 6% at 442 nm, but increases to 35% at 804 nm and 53% at 1064 nm. The absorption is high at short wavelengths, with 40% at 442 nm, but it is only 6% at 804 nm and 1064 nm. The reflection is generally higher than 40% and shows little wavelength dependence. The transmitted light is scattered diffusely at short wavelengths, but at 804 nm and 1064 nm it exhibits a fairly narrow angular distribution in the forward direction. Fiber contact leads to an increase in transmission, with a factor of 3.5 at 442 nm, of 2.0 at 804 nm, and of 1.5 at 1064 nm. Our results indicate that the diode laser (804 nm) and the Nd:YAG laser (1064 nm) are best suited for transscleral photocoagulation and that contact delivery leads to a reduction of the energy required for cyclophotocoagulation.
The effect of the positioning of the needle in the horizontal plane and the applied clenching force on the result of the needle point tracing was investigated. The results show a strong influence of the applied clenching force. The results on the variation of the needle position leaded to the conclusion, that in the progress of the needle point tracing the lower jaw is balanced over the central bearing point.
We report a patient with the characteristic features of the brittle cornea syndrome, a rare, autosomal recessively inherited disorder, namely brittle corneae, blue sclerae, and red hair. The patient also showed joint hyperextensibility, a soft skin, and dysplastic auricles with unusually soft cartilage. Phenotypically, the disorder bears a certain resemblance to fragilitas oculi and the type VI (ocular) form of the Ehlers-Danlos syndrome, two conditions which are, themselves, not readily distinguishable. However, the hydroxylysine content of dermal collagen was normal, as was the activity of lysyl hydroxylase in cultured dermal fibroblasts, thus supporting the distinction of the brittle cornea syndrome as an independent entity. No abnormality was discernible in types I or III collagens synthesised by cultured fibroblasts, but electron microscopy revealed dramatic ultrastructural alterations in dermis in that distributed over its whole thickness were 20-60 microns wide "holes" or fibre-free spaces, filled with an amorphous material.
The damage mechanisms of intraocular Nd:YAG laser surgery and their respective damage ranges were investigated in vitro using bovine cornea specimens as a model tissue. The main damage mechanisms are plasma formation and expansion, emission of acoustic transients, and cavitation with jet formation. When a sequence of laser pulses is applied, the interaction of the acoustic transients with gas bubbles remaining from preceding laser exposures is also important. To distinguish the effects caused by the different physical mechanisms, laser pulses were aimed directly onto the corneal endothelium, and parallel to the cornea at various distances. Simultaneously, the cavitation bubble size was determined. The surface morphology and sections of the same lesions were studied by light and electron microscopy. The primary surgical mechanism is tissue evaporation by the laser plasma, whereas the collateral damage from single laser pulses is mainly caused by the cavitation and jet formation. The damage range after a 4-mJ laser pulse is 0.8 mm which is slightly larger than the corresponding cavitation bubble radius. The damage range of the acoustic transients produced by a 4-mJ laser pulse is several millimeters, when they can interact with small gas bubbles attached to the corneal endothelium. The damage range of the acoustic transients alone is smaller than that of cavitation as far as damage detected by light and scanning electron microscopy is concerned. However, on a subcellular level the acoustic transients may possibly cause damage up to a much larger distance. The damage range observed varies with the cube root of the laser pulse energy. A reduction of collateral effects therefore requires the use of small pulse energies. For energies of less than 1 mJ, the pulse duration has to be reduced to ensure plasma production. It is proposed to use low-energy picosecond pulses with moderate repetition rate instead of single nanosecond pulses to reduce collateral damage effects.
An epidemiological survey was conducted on the cadmium intoxication of 132 residents living on former sewage fields. Besides 'global biological monitoring', the relation between the cadmium secretion in urine and the load of cadmium of the kitchen gardens and flower gardens was analysed. There were significant correlations between the cadmium concentration of the residents' garden soil and their daily urine secretion, particularly for older nonsmokers who admitted "at least occasional consumption" of products from their gardens. The value of applying non-parametric correlation coefficients is proven.
In September 1983, we selected 30 villages in four rural counties of northern Haiti for a partial census and malaria prevalence survey. A cohort of 1,577 persons was enumerated in this census. Survey teams revisited the same houses in these villages in September 1984 and updated the previous census, inquiring about all listed family members. We administered an additional questionnaire to each household concerning the occurrence over the past year of deaths, births, pregnancies, and migration. Among the 1,218 persons who had been followed for one year, there were 21 deaths (crude mortality rate: 17 per 1,000 population; 95% confidence interval [95% CI]: 12 per 1,000, 25 per 1,000) and 35 births (birth rate: 29 per 1,000 population year; 95% CI: 19 per 1,000, 38 per 1,000). The infant mortality rate was 171 per 1,000 live births (95% CI: 81 per 1,000, 315 per 1,000), and the mortality rate for children less than 5 years old was 36 per 1,000 (95% CI: 24 per 1,000, 56 per 1,000). Although small sample surveys are subject to limitations of precision dependent on sample size, they can be a simple method by which researchers may estimate vital statistics for rural areas of less-developed countries.
With the help of video- and computer techniques is investigated in what respect the forces operating in intraoral tracing pin registration have an influence on the mandibular movement at the sagittal plane. The results significantly show this dependence.
It was the purpose of this study to assess the influence of the applied clenching force and the positioning of the needle in the sagittal plane on the results of needle point tracings. The results show a direct influence of the applied force, whereas the influence of the position of the needle point showed great interindividual variations.
The recording of the mandibular movement at a horizontal plane were described by Gysi, McGrane, Marxkors and Solomon also by Kleinrok. Our improvement at the recording set refers to the anchoring by means of which repeated recordings are possible in both patients with teeth and patients with a denture.
The performance of schizophrenic patients in a task which requires a sequence of saccades guided by visuospatial cues is reported. A previous study recording eye movements determined a highly increased number of fixations necessary for this task in acute schizophrenic patients compared with normal controls. The performance of normal control subjects of different age groups and the correlation between the performance in the tracking task and the results of a clinical psychological test battery are described. Schizophrenic patients in a partly remitted state and in a remitted or mildly chronic state performed this task worse than matched control subjects; this was particularly indicated by the time score. The relation to the lifetime dosage of neuroleptic medication is considered.
A patient with epidermolysis bullosa simplex with mottled pigmentation is described. Clinical features include blistering of the skin, especially of the extremities; healing without scars; slight atrophy of the skin; and striking mottled pigmentation of the trunk. Histologic examination of a biopsy specimen from freshly frictioned, clinically uninvolved skin indicated a split inside the basal keratinocytes, focal hyperpigmentation of the basal cells, and pigment incontinence without an inflammatory infiltrate. Indirect immunofluorescence demonstrated focal discontinuity of the basement membrane zone. Electron microscopic examination revealed basal keratinocytes with few intact intracellular organelles, aggregated tonofilaments, and subnuclear splitting with the basal parts of the cells adhering to the basement membrane. Both normal basement membrane and zones of irregular and interrupted structures were seen. Hemidesmosomes and anchoring fibrils appeared to be normal.
The penetration depth of laser light into the fundus is dependent on the wavelength. Thereby, the profile of damage depends on the absorption and on the temperature profile. It has been demonstrated earlier that wavelength-dependent differences in penetration depth are hard to detect ophthalmoscopically or histologically in severe lesions in Chinchilla gray rabbits. Therefore in this study, the wavelength-dependent exposure powers necessary for (1) similar retinal effects and (2) similar choroidal effects were compared. The resulting wavelength-dependent differences were smaller than expected-due to at least three reasons: (1) predominance of the temperature profile over the absorption profile for clinically useful exposure times; (2) light scatter in the retina in relationship to the exposure time (and wavelength?): (3) changes in the choroidal geometry in relationship to the exposure time and wavelength. Nevertheless, it appears to be possible to spare the retina somewhat by using longer wavelengths. In order to evaluate the clinical situation experimentally despite the fact that the human choroid is about three times thicker than the rabbit choroid, a geometrical model has been developed. The results indicate that the retina is less damaged using Nd:YAG lasers than using argon lasers when similar choroidal effects are produced.
1. Canine saphenous veins were investigated in vitro either within 24 h after removal or after storage at -190 degrees C for 4-5 weeks of foetal calf serum containing 1.8 M dimethyl sulphoxide. 2. Contractions and 45Ca2+ uptake in response to both depolarization and guanfacine were studied in the absence and presence of the calcium channel antagonists diltiazem, verapamil, nifedipine and the two stereoisomers of a 1,4-dihydropyridine derivative, namely the (+)-(S) enantiomer and the (-)-(R) enantiomer of 202-791 (isopropyl 4-(2,1,3-benzoxadiazol-4-yl)-1,4-dihydro-2,6-dimethyl-5-nitro-3- pyridinecarboxylate). 3. Comparison of the data obtained on unfrozen and frozen/thawed veins revealed a good preservation of both contractile responsiveness and 45Ca2+ uptake mechanisms after storage at -190 degrees C. 4. It is suggested that cryopreservation is a useful technique for storing venous smooth muscle for pharmacological studies.
The influence of artificial unilateral occlusal disturbances on the structure of the temporomandibular joint (TMJ) condyle cartilage was investigated by an experimental study using the miniature pig "MINI-LEWE". After a burden over 20 weeks the side exposed to occlusal disturbance (right TMJ) turned out to have unchanged histological proportions in comparison with control animals. The condyles of the side with pressure loading (left TMJ) exhibited but a changed histological picture. Cartilage resorptions as well as accumulations of large blown chondrocytes indicate an increased tissue reaction within the chondroblastic layer near spongiosa. The morphometric investigations confirm these results. A significant increase was observed in cell density within the chondroblastic layer of the most superior point of the left condylus due to the permanent disturbance of the normal masticatory function.
The activator protein for the enzymatic hydrolysis of sulfatide, ganglioside GM1, and globotriaosylceramide was purified from human kidney, brain, and urine. As far as they could be assayed, these three activities cochromatographed during all steps, indicating that they are due to the same protein. This result was corroborated by immunochemical comparison of individually purified activator preparations. In contrast, the activator for ganglioside GM2 hydrolysis could clearly be separated from the other activities. Kinetic data were determined for the interaction of the sulfatide activator with the different glycolipids and hydrolases.
An 11-year-old patient with clinically typical acrogeria is presented. She had wrinkled 'old-appearing' acral skin, thin skin on the whole integument, grooved tip of nose, mottled hyperpigmentation of fold regions and thickened dystrophic toe nails. Histologically, the epidermis was flattened, dermis thinned and the connective tissue densely packed with very few cellular elements. Electron microscopic examination revealed partially abnormal collagen fibers with varying caliber, degenerated elastic fibers and dystrophic fibroblasts. The patient's fibroblasts produced normal amounts of apparently normal type I and III collagen as analyzed after radioactive labeling. Also, the levels of cytoplasmic mRNA for both of these collagens were similar in acrogeria and control cells.
In order to examine characteristics of nondangerous and nonpsychotic patients referred to a consultation service, the authors administered self-rating scales and questionnaires to fifty referred medical patients and nonreferred controls. Recalled abuse in childhood appeared a stronger predictor for referral than some other commonly researched ones such as parental death, divorce or separation in childhood or recent losses. Anxiety, hostility and depression were significantly higher in referred patients, whereas hypochondriacal attitudes did not differ between the two groups. The findings appear to have implications for treatment.