Biomedical subjects
K Frank
Publications and source records attributed to K Frank.
Analysis of multiple multipole scattering by time-resolved spectroscopy and angular dependent spectrometry.
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Monitoring of intracapillary HbO2 in foetal scalp during delivery.
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Monitoring of redox-state of respiratory enzymes and myoglobin oxygenation in the working rat heart in normoxia and oxygen deficiency.
The cellular oxygen supply in the isolated, hemoglobin-free perfused, working rat heart can be determined by measurements of myoglobin oxygenation. However, for a precise analysis of mitochondrial hypoxia and anoxia (pO2 < 0.01 Torr) redox-state of respiratory enzymes must be known. By use of the EMPHO (Frank et al. 1989) it is possible to perform a high speed spectrometry within very small tissue volumes. Because of the characteristic absorption spectra of oxygenated and deoxygenated myoglobin and of the oxidized and reduced cytochrome aa3 within the wavelength interval from 500 to 630 nm it is possible to isolate these two pigments from the remission spectra and to determine the oxygenation state of myoglobin and the redox-state of cytochrom aa3.
[Validation of the Child Speech Test using the Heidelberg Speech Development Test with six-year-old preschool children].
We present and discuss results from researches to validate a new test for diagnosing speech-competences of preschool children KISTE. 41 children (6;0-6;11) were tested both with KISTE and HSET. Correlations, factor- and clusteranalysis showed that the structure of both tests is different and that KISTE has a good differential validity for both aspects of speech: communicative and structural.
Spectrometric measurements in the anterior eye vasculature of the albino rabbit--a study with the EMPHO I.
Intracapillary haemoglobin oxygenation (oxygen saturation) and haemoglobin concentration (corresponding with blood volume) were measured in different regions of the albino rabbit anterior eye segment using the Erlangen micro-lightguide spectrophotometer (EMPHO I). The tip of the microlightguide (active diameter 210 microns, cover diameter 0.5 mm) was placed in the vitreous by a goniometric mounting and controlled by a micromanipulator. After stepwise elevation of intraocular pressure (IOP) the haemoglobin oxygenation decreased slightly in the iris at an IOP-level of 60 mmHg, whereas in the three regions of the ciliary processes and in the peripheral choroid haemoglobin oxygenation did not decrease until values of 80 mmHg were applied. In contrast, haemoglobin concentration decreases when the IOP increases in all regions except in the pars plana where the haemoglobin concentration increased at 40 and 60 mmHg. The most pronounced reactive hyperaemia was found in the major ciliary processes. Quite passive changes of haemoglobin concentration were seen in the peripheral choroid. Effective regulatory mechanisms must exist which result in IOP-independent (20-60 mmHg) haemoglobin oxygenation, whereas pronounced changes in intracapillary haemoglobin concentration were observed. The decay of both parameters at IOP 80 mmHg is indicative of an exhaustion of their regulatory capacity. Epinephrine topically applied onto the conjunctival sac or injected into the common carotid artery led to a short-term decrease of haemoglobin concentration and, later, a hyperaemic response. A short-term haemoglobin deoxygenation was found especially in the major ciliary processes.
Analysis of the immunoregulatory capacity of anti-alpha/beta-TCR and anti-CD3 monoclonal antibodies.
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The effect of fluoride on the resorption of dentine by osteoclasts in vitro.
Osteoclasts were isolated mechanically from bones of prehatch chicks and cultured on dentine for 24 or 39 h in medium without or with added sodium fluoride at concentrations of 0.15, 1, 15, or 30 mg/liter. Fixed and toluidine blue-stained specimens were examined by light microscopy and osteoclasts were counted, all cells were removed and resorption pits were counted. The dentine was then prepared for scanning electron microscopy (SEM) and pits located on a raster search using backscattered electron imaging. Stereophotogrammetric measurements were made of the depths, plan and true surface areas and volumes of pits, and the volume:area ratio and a three-dimensional form factor calculated for each. The presence or absence of a ring of demineralization around each pit was recorded. Pits with the same plan area were significantly (p less than 0.001) less deep in cultures containing 15 or 30 mg/liter NaF and the incidence of rings around pits was higher (controls 2.7%, 15 mg/liter 31.3%, 30 mg/liter NaF 39.7%). In one experiment, pits were larger in the specimen cultured with added 1 mg/liter NaF, but in a much larger series of 631 (251 in the control and 380 in the 1 mg/liter NaF cultures) pits measured, depths, volumes and volume:plan-area ratios were significantly lower (p less than 0.001), and rings round pits 2.5 times more common, in the fluoride-treated group. A complex interplay of stimulation of some cells in the culture with indirect stimulation of osteoclasts and direct inhibition of osteoclastic resorptive function may be operating at this concentration of fluoride. In vivo, therapeutic doses of sodium fluoride would be expected to act not only to increase the formation of osteoid but also to suppress osteoclastic activity.
[Echogenic splenic lesions--incidence and differential diagnosis].
In order to estimate the incidence and clinical relevance of echogenic focal lesions in the spleen, 121,372 ultrasound investigations from seven laboratories were evaluated. Ninety-two cases with echogenic lesions in the spleen were reviewed (incidence: 3.2 to 14.2 of 10,000 patients). Differential diagnosis included neoplastic tumors (17.4%; five metastases, three lymphomas, seven hemangiomas, one lymphangiomatosis), vascular disorders (17.4%: bleeding, infarct) and inflammatory focal lesions (8.7%; abscess, calcifications). Follow-up studies showed no change in size and pattern in a further 17.4% of the lesions, indicating benign disorders. Thirty patients suffered from a malignant condition with splenic metastasis or lymphomas in eight cases. In a further five patients, it was possible to confirm echogenic hemangiomas. There are no specific echographic patterns which differentiate hemangiomas from malignant tumors.
[Endosonographic staging of rectal tumors].
Pre-operative staging was performed in 81 patients with rectal tumours by means of endorectal sonography. In 87% of cases (70 out of 81), the endosonographic findings corresponded with the histopathological appearance; the recognition of T0 and 1 tumours, which is important in deciding surgical procedures, was possible in 94% (51 out of 54). Differentiation between T0 and T1 tumours (i.e. between adenomas and carcinomas infiltrating the submucosa) was not possible. Five out of ten of T2 and 14 out of 16 T3 tumours were staged correctly. One T4 tumour was placed in too low a stage. A comparison of the echo structure of adenomas and carcinomas in 76 patients showed that 28 out of 43 adenomas (65%) have homogeneous echoes, while 24 out of 33 carcinomas (73%) showed inhomogeneous low intensity echoes.
[The development of the assortment and requirements of the tissue bank of the District Institute for Blood Donation and Transfusion Leipzig].
Since the foundation of the tissue bank at the District Institute for Blood Donation--and Transfusion Service of Leipzig in 1966 the range of production and the assortment of nonvital tissue transplants has considerably increased. The amount of clinical establishments and their requirements is considerably increased, in which the realization of demands is not always possible without waiting periods. The main tissue conservation method is the cryo-drying. Besides the extreme cooling and cryo-preservation were used. Problems of transportation of cooled tissue conserves were discussed.
Primary glucocorticoid receptor defect with likely familial involvement.
A 29-year-old woman with moderately elevated blood pressure and signs of hyperandrogenism (hirsutism and acne) but without typical Cushing's syndrome symptoms has been followed for almost 6 years. Steroid and glucocorticoid receptor studies indicated a primary glucocorticoid receptor defect. Elevated androgen values were of special interest. Clinical manifestation of hyperandrogenism seemed not to be proportional to the biochemical findings. Therefore, the possibility of a partial androgen receptor defect should also be considered.
Endoluminal ultrasonic examination of sessile polyps and early carcinomas of the rectum.
The results of conventional endosonographic techniques in the assessment of early carcinomas and sessile polyps of the rectum have been unsatisfactory. We therefore developed a new technique in which the rectal cavity is filled directly with water. Using this technique, the anatomy of small rectal tumors is preserved and the layers of the rectal wall are easier to differentiate, especially with a 10-MHz scanner. The clinical results in 66 patients demonstrate that this new technique is very accurate in the preoperative staging of adenomas and T1-carcinomas of the rectum.
Endoluminal sonography in follow-up of rectal carcinoma.
Fourteen patients who had undergone local excision, anterior resection or low anterior resection for rectal carcinoma were examined by endoscopic ultrasonography. In two of three cases of local recurrent carcinomas, endoscopic sonography was superior to computed tomography in determining the depth of tumor infiltration. There were difficulties in differentiating scar tissue from local tumor formation when the mucosa appeared normal upon endoscopic examination. Only repeated follow-up examinations starting in the postoperative period, will allow a differentiation between scar tissue and local tumor recurrence.
Can the routine treatment of Graves' orbitopathy be efficiently supplemented by the administration of Venalot?
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[New endosonographic examination technic for improving the assessment of small rectal tumors].
Conventional endosonographic techniques of examination in early carcinoma and sessile rectal adenoma have shown unsatisfactory results. We therefore fill the rectal cavity directly with water. Using this technique the anatomy of the rectal polyp is preserved, and the separate layers are easier to differentiate, especially when the 10-MHz scanner is used. The clinical results in 56 patients show an improvement concerning the preoperative staging especially in those tumors which are not palpable.
[Diagnosis of Paget's disease of bone].
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[Therapy of Paget's disease of bone].
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