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Biomedical subjects

P Kann

Publications and source records attributed to P Kann.

48 records · Page 3Linked to original sources
PubMed1995

Validation of a mechanical method for measuring skin thickness: relation to age, body mass index, skin thickness determined by ultrasound, and bone mineral density.

In a number of endocrine disorders, typical changes in skin thickness can be observed which make measurement of skin thickness interesting in this field. A newly developed mechanical method for measuring skin thickness is presented. Using a digital measuring screw on the dorsum of the hand with a defined measuring force of 10 newton and a resulting tissue compression of 1500 mm Hg, highly reproducible results were obtained (mean coefficient of variation 2.56%). In 129 women, 37 to 78 years old, body mass index < 30 kg/m2, there was no significant relation between body mass index and skin fold thickness. A negative correlation between skin fold thickness and age (r = 0.37, p < 0.001) was detected. This has been shown for skin by other methods previously and is well known to occur in bone, another tissue whose matrix as well as dermis consists mainly of collagen type I. In 30 subjects, half hypopituitary patients, half healthy subjects (17 women, 13 men; 43.3 +/- 10.5 years old), skin fold thickness measured mechanically and sonographically determined skin thickness correlated with r = 0.46 (p < 0.01). A significant correlation between bone mineral density measured by single photon-absorptiometry at the ultradistal forearm and skin fold thickness measured mechanically was found and skin fold thickness measured mechanically was found (r = 0.36, p < 0.05), whereas this was not the case for sonographically determined skin thickness and bone mineral density (r = 0.13, n.s.). This newly developed method might be useful in clinical studies on endocrine disorders affecting skin (and bone) metabolism and the regulation of collagen type I metabolism in general.

Adult↗
PubMed1995

Peripheral osteopenia in adult patients with insulin-dependent diabetes mellitus.

Alterations in bone metabolism in diabetes mellitus is a topic of special interest. Bone blood flow is increased in the distal limb of diabetic patients, which is believed to increase osteoclastic activity. We measure bone mineral density using dual-photon absorptiometry in the distal lower limb, the femoral neck, and the lumbar spine in 41 IDDM patients and in 30 control persons. In the diabetic group there was a 10% reduction of bone mineral density in the femoral neck (p < 0.01) and a 12% reduction in the distal limb (p < 0.001) compared with the control group. No significant difference was found in the lumbar spine (p = 0.22). Our data yield incidence for peripheral osteopenia in IDDM-patients, independent of any systemic bone disease such as osteoporosis. A link between decreased bone mineral density and diabetic neuropathy has been observed for the femoral neck (p < 0.001), but not for the distal limb or axial skeleton. Whether there is a common aetiological link or a casual connection between diabetic neuropathy and bone mineral density has still to be determined.

Absorptiometry, Photon↗
PubMed1994

Age-dependence of bone material quality shown by the measurement of frequency of resonance in the ulna.

In women before and after the age of peak bone mass, identical values of bone mineral density (BMD) can be obtained. However, there is a much higher incidence of osteoporotic fractures in older women. We investigated whether a deterioration of bone material quality with increasing age might contribute to this phenomenon. Material properties of bone tissue can be characterized by the modulus of elasticity, which is correlated to the square of sound transmission velocity. In this study, sound transmission velocity was determined in cortical bone by measuring the frequency of resonance in the ulna in the direction of the bone's longitudinal axis and correcting the values by multiplying by ulna length. Validation of this method indicated acceptable reproducibility: interobserver variability determined as the mean coefficient of variation was 1.82%. In a clinical study, 21 young women (22.5 +/- 1.2 years old) were compared with 21 middle-aged women (52.9 +/- 2.7 years old). Pairs were matched that had identical values of BMD in the nondominant forearm at a location representing mainly cortical bone (SPA). The product of ulna length and frequency of resonance in the ulna in the younger women was found to be 61.4 +/- 5.8 m/second, and in the middle-aged women 55.7 +/- 4.5 m/second. The difference was highly significant with P < 0.005. Our results confirm recent findings indicating a deterioration of bone material quality independent of BMD with increasing age.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Association between "diabetic thick skin syndrome" and neurological disorders in diabetes mellitus.

Skin thickness on the extremities of patients with diabetes mellitus has been described controversially. Using high resolution ultrasonography, we were able to show a significant increase in skin thickness at the forearm (P < 0.05), thigh (P < 0.001) and lower limb (P < 0.05) of diabetic patients, most prominent at the thigh. No difference in skin thickness was found at the dorsum of the foot. In addition, skin thickness was not related to the duration of diabetes, age or HbA1. A close association was found between diabetic neuropathy and increasing skin thickness. Diabetic patients with neurological disorders had a significant increase in skin thickness versus diabetic patients without neuropathy. The present findings suggest that diabetic neuropathy and abnormalities of connective tissue have a common etiological link in their development or that both are time-dependent processes. Whether changes in capillary blood flow, increase of nonenzymatic glycosylation, polyol accumulation or other metabolic disorders are responsible for these findings remains still to be established.

Adult↗
PubMed1993

[Driver's license and diabetes. Legal and social medicine aspects].

The diagnosis of diabetes mellitus is accompanied by a lot of personal and social consequences for the patient himself. One of the most important problems is the influence of the disease on the patients driving skills. This aspect is discussed according to the recommendations of the German ministry of traffic, and advice is given for the diabetic patient taking part at the daily traffic as a car driver.

Accidents, Traffic↗
PubMed1993

[Backache and osteoporosis in perimenopausal women].

Osteoporosis is thought to represent one of the main causes of back pain in perimenopausal women. One hundred perimenopausal women (45 to 60 years) who were consecutively admitted in order to clarify the cause of their back pain were examined. In 20% disc degenerations were found. Other degenerative disorders (osteoarthritis) of the spine without coincident scoliosis were found to be the second most common cause of pain in 19%. Scoliosis due to different leg length was detected in 15%, idiopathic scoliosis in 13%. Spondylolisthesis occurred in 7% even more frequently than osteoporosis with vertebral deformities in 6%. Non-osteoporotic vertebral deformities were seen as often as osteoporotic ones. Rare diagnoses among others were seronegative spondyloarthropathy and fibrositis. Our results indicate that back pain in women up to 60 years is mostly due to degenerative disorders of the spine. Osteoporosis with vertebral deformities as cause of pain is quite rare. Comparing bone mineral density of the distal forearm (SPA) of the patients with back pain not due to manifest osteoporosis (98 +/- 15% of age related mean) with those of 50 asymptomatic women (96 +/- 14%) and 50 female patients with pain in other regions of the skeleton (103 +/- 17%) in the same age group, there was no evidence for any relation between low bone mineral density and skeletal pain.

Female↗
PubMed1993

Architecture in cortical bone and ultrasound transmission velocity.

The square of ultrasound transmission velocity in a material is correlated to the modulus of elasticity, which is an indicator of its mechanical properties. This might make the measurement of ultrasound transmission velocity useful in the noninvasive diagnosis of bone diseases. Bone, however, is not an isotropic material but is architecturally structured. The aim of our study was to investigate and especially to quantify the influence of architecture in cortical bone on ultrasound transmission velocity. Twenty-two rectangular, flat specimens of cortical bone were prepared from diaphysis of fresh pig radius. Ultrasound transmission velocity was measured parallel and perpendicular to direction of Haversian channels. It was found to be 3647 +/- 41 m/s parallel to and 2821 +/- 29 m/s perpendicular to Haversian channels respectively (p < 0.001). Our results clearly indicate that there is an important influence of architecture in cortical bone on ultrasound transmission velocity which has to be taken into account in its clinical use.

Animals↗
PubMed1993

[99mTc-MAG3-kidney function scintigraphy without and with captopril in the diagnosis of renovascular hypertension].

In this study, the diagnostic value of renal function scintigraphy performed both without and with ACE inhibition has been evaluated using the new radiopharmaceutical 99mTc-MAG3. In cases of decompensated renal artery stenoses, the typical scan finding with this tubular excreted agent was shown to be a distinct parenchymal nuclide retention in combination with a delayed appearance of the radiotracer in the pelvic system. Using this criterion in 43 patients with suspected renovascular hypertension, sensitivity and specificity were 89 and 88%, respectively. Bilateral positive findings were non-specific; excluding them from the study, specificity increased to 100%. In renal insufficiency, captopril scans seem to be of reduced diagnostic value. Summarising our experiences, renal function scintigraphy using 99mTc-MAG3 without and with captopril was proved to be a reliable non-invasive method to detect or exclude haemodynamically relevant renal artery stenosis.

Captopril↗
PubMed1993

[Evaluation criteria for captopril-kidney function scintigraphy using 99mTc-MAG3].

Renal function scintigraphy under ACE inhibition has gained an important role in the diagnosis of renovascular hypertension. Using the radiopharmaceutical 99mTc-MAG3, 54 kidneys with angiographically verified renal artery status were evaluated with respect to the following scintigraphic parameters: intraparenchymal tracer transport, urine drainage, kidney size, and functional side-to-side ratio. In cases of decompensated renal artery stenosis, the typical scan finding using MAG3 was shown to be a distinct parenchymal nuclide retention in combination with a delayed appearance of the radiotracer in the pelvic system. In our patients, the visual impression of the renal sequential scans was superior to quantitative evaluation methods. Using these criteria in 43 patients with suspected renovascular hypertension, sensitivity and specificity were 89% and 88%, respectively. Bilateral positive findings were nonspecific; when excluding them from the study, specificity increased to 100%.

Adult↗
PubMed1990

Different muscarinic receptors mediate autoinhibition of acetylcholine release and vagally-induced vasoconstriction in the rat isolated perfused heart.

Experiments were carried out on rat isolated perfused hearts with both vagus nerves attached. The acetylcholine stores were labelled with [14C]-choline. The effects of muscarinic receptor antagonists on the [14C]-overflow and increase in perfusion pressure evoked by vagus nerve stimulation (10 Hz, 4-10 mA) were studied in order to determine the muscarinic receptor type involved in autoinhibition of acetylcholine release and vagally-induced vasoconstriction in the rat heart. Stimulation of the vagus nerves (1200 pulses) caused an increase in [14C]-overflow and in perfusion pressure which was significantly reduced by hexamethonium 500 mumol/l and abolished by tetrodotoxin 0.3 mumol/l or perfusion with Ca2(+)-free solution. The fractional rate of evoked [14C]-overflow per pulse upon stimulation at 10 Hz (720 pulses) was doubled in the presence of the non-selective antagonist atropine (0.01-1 mumol/l) as well as in that of the M2-selective compounds methoctramine (0.1 mumol/l) and AF-DX 116 (0.1-1 mumol/l), but remained unaffected by the M3-selective hexahydrosiladifenidol (0.1 mumol/l). The increase in perfusion pressure upon nerve stimulation was reduced by atropine (0.01 mumol/l) or hexahydrosiladifenidol (0.1 mumol/l) to approximately 50% and increased by about 50% in the presence of AF-DX 116 (0.1 mumol/l). The results show that the autoinhibition of acetylcholine release in the rat heart is mediated by M2 receptors. On the other hand, the increase in perfusion pressure upon vagus nerve stimulation is caused by a different muscarinic receptor, more sensitive to hexahydrosiladifenidol than to M2-selective antagonists.

Acetylcholine↗
PubMed1989

[Osteoporosis: a case report].

A 56-year-old female patient was admitted to our hospital because she was suffering from severe osteoporosis. The patient had experienced repeated spontaneous fractures for 1.5 years such as serial rib fractures, fractures of the sternum and most recently fracture of the neck of the femur after a minimal trauma. Histology revealed a low-turnover-osteoporosis. Subsequent radiologic examination showed extreme osteoporosis of the skeleton with numerous compression fractures of the vertebral bodies as the most outstanding finding. The bone histology and the relatively short history of spontaneous fractures led us to investigate endogenous hypercortisolism as a possible cause although clinical signs were absent. An attenuated diurnal variation of cortisol levels and lack of suppressibility of cortisol was found. Furthermore, magnetic resonance tomography showed a microadenoma of the pituitary gland. Computerized tomography of the adrenals was normal. Transsphenoidal surgery confirmed the tentative diagnosis and histological examination revealed a bilateral adenoma of the pituitary gland.

Adenoma↗