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Biomedical subjects

W Kühnel

Publications and source records attributed to W Kühnel.

At least 73 records · Page 4Linked to original sources
PubMed1992

[The olfactory region of the bat Scotophilus heathi. Light and electron microscopic studies].

The present investigation reports light and electron microscopical aspects of the main olfactory epithelium (MOE) of the insectivorous bat Scotophilus heathi. Serial frontal sections of the nose and associated structures reveal: 1) that the MOE is located on most of the ethmoturbinals and on the proximal upper portion of the nasal septum; and 2) that the vomeronasal organ is absent in this species. The ultrastructure of the MOE of Scotophilus heathi is similar to that observed in other vertebrates. Moreover, we did not observe significant morphological differences between the MOE of male and female animals. Nevertheless, the supra-nuclear region of the supporting cells of males and females shows a different amount and distribution of "lysosome-like" cell organelles at the two times of the year investigated.

Animals↗
PubMed1992

[The effect of cyclooxygenase inhibitors on the course of hereditary retinal dystrophy in RCS rats].

Daily administration of acetyl salicylic acid (ASA) and ibuprofen leads to an appreciable retardation in the process of retinal degeneration in the RCS rat which is dependent on the dosage given. The photoreceptor cell nuclei and inner segments are relatively well preserved in all regions of the retina. While the outer nuclear layer of 32 day old RCS rats is usually composed of only 3-4 rows, we found 8-9 nuclear rows exhibiting minimal pyknotic change in animals which had been treated with higher doses of ASA. These differences in layer thickness could be confirmed using morphometric analysis. The outer segments show evidence of degenerative change although they are in a clearly better condition than those found in untreated animals and in those animals treated at lower dose. Phagolysosomal structures which are not otherwise apparent in this strain of rat are detected only in the RPE cells of animals treated with higher dose. The animals treated with ibuprofen show essentially the same morphological changes although a corresponding effect in regard to the thickness of the outer nuclear layer was only achieved after a high dose. The determined dose for the optimal preservation (thickness) of the outer nuclear layer lies around 160 mg/kg body weight for acetyl salicylic acid and at 400 mg/kg body weight for ibuprofen.

Animals↗
PubMed1991

Postnatal changes in the ultrastructure of the rat olfactory epithelium: the supranuclear region of the supporting cells.

The present electron-microscopical study reports ultrastructural changes occurring in the supranuclear region of the supporting cells of the rat olfactory epithelium during the first 16 days of postnatal life. These changes are concerned with the enclosure of receptor cell dendrites and an increase in the amount of smooth endoplasmic reticulum, which has a specific distribution in the supporting cell. An increase in microvillous projections at the free cell surface is also observed. Moreover, this report demonstrates that the cytoarchitecture of the apical portion of the olfactory epithelium at the 16th day of postnatal life is similar, with respect to the relationship between supporting cells and receptor cell dendrites, to that of adult animals.

Animals↗
PubMed1991

[Lectin histochemistry on the olfactory region and the vomeronasal organ or rats and golden hamsters].

The present investigation describes the lectin-binding properties of the regio olfactoria (RO) and the vomeronasal organ (VNO) of the rat and golden hamster. Special attention is paid to the lectin-binding properties of the chemosensory epithelia as well as to the reactions of their specific glands. The following lectins were used: wheat germ agglutinin (WGA), horseshoe crab agglutinin (LPA), gorse agglutinin (UEA I), peanut agglutinin (PNA), soybean agglutinin (SBA), and horse gram agglutinin (DBA). Lectin-binding procedure was performed on paraffin sections of the RO and VNO using the peroxidase-antiperodixase method. Comparisons of the lectin-binding properties of the surface of the main olfactory epithelium (MOE) with that of the neuroepithelium (NE) of the VNO as estimated by the intensity of staining demonstrate that in both species differences exist between the lectin-binding properties, of the MOE and VNO-NE. Moreover, some reactions of the MOE and VNO-NE differ from species to species.

Animals↗
PubMed1989

[CT of the upper ankle joint. Anatomy--pathology].

Diagnosis of ligament ruptures via the possibilities of conventional radiology is often insufficient. To verify CT efficiency, postmortem specimens were scanned in axial, coronal and sagittal planes and compared with anatomical findings of sections in identical planes. After the preliminary examinations we conducted a study on 32 patients. The examinations of the anterior talofibular ligament showed a correlation between CT and operative findings in 30 of 32 cases.

Adolescent↗
PubMed1989

Mechanistic study on formaldehyde-induced hepatotoxicity.

In isolated, hemoglobin-free perfused livers of fasted rats, formaldehyde at an initial concentration of 10 mmol/l produced toxicity as evidenced by a release of enzymes (GPT, SDH) and of glutathione (mainly GSSG) into the perfusate, an accumulation of calcium in the liver, and a depletion of hepatic glutathione. Formaldehyde also led to an enhanced release of malondialdehyde into the perfusate, indicating peroxidative processes and decreased hepatic oxygen consumption by about 50-70%. The electron microscopic investigation of formaldehyde-exposed livers showed a destruction of the mitochondria (ruptured membranes, loss of the cristae) and some damage of the rough endoplasmic reticulum. Feeding the rats prior to surgery attenuated the hepatotoxic effects of 10 mmol/l formaldehyde. At an initial concentration of 3 mmol/l, formaldehyde did not release enzymes from livers of fed or fasted rats but only from those whose glutathione content had been depleted by treatment with phorone (250 mg/kg ip 2 h earlier). Formaldehyde liberated glucose and lactate from the livers of fed but not from those of fasted rats, indicating anaerobic energy supply in the fed state. The hepatotoxic action of formaldehyde is not due to its metabolism to formate or to the 10% methanol added as a stabilizing agent to the commercially available 37% solution named formalin. In conclusion, by destruction of mitochondria, formaldehyde inhibits aerobic energy supply and thereby presumably produces hepatocellular damage.

Alanine Transaminase↗
PubMed1989

[beta-Thromboglobulin concentration, thrombocyte count and thrombocyte volume from four selected sample collections].

beta-Thromboglobulin, blood platelet count and blood platelet volume are presented by a reference group (N = 30) and are compared with a group of patients having mild thrombocytopenia, migraine and renal disease before, during as well as after dialysis. Patients with migraine have statistically significant differences regarding these three parameters in comparison to the reference group. Renal patients demonstrate a marked increase of the beta-thromboglobulin values during dialysis and a rapid decrease two hours afterwards.

Adult↗
PubMed1989

[Short-term versus long-term chemoprevention of recurrence with Epodyl following transurethral resection of superficial urinary bladder cancer].

This investigation compares the short and long-term administration of intravesical Epodyl (etoglucid), following transurethral bladder tumor resection. This chemoprophylactic agent was used specifically in the treatment of bladder tumors that displayed different associated tumor risk factors: solitary versus multiple tumors, grade(s) I-III, primary versus recurrent tumors, and the presence of associated dysplasia. Within this study, 114 patients with carcinoma of the bladder underwent primary transurethral resection (TUR), followed in 10 days by short-term intravesical therapy (STIT) or long-term intravesical therapy (LTIT). Short-term intravesical therapy was administered to 56 patients. The therapy consisted of a 1% solution of Epodyl, which was given once per week for 6 weeks. Long-term intravesical therapy was given to 58 patients. This consisted of the short-term intravesical therapy protocol, followed by an additional dose once a month during an observation period of 2 years. The follow-up in both groups was for a minimum of 2 years. When the total number of recurrences in patients receiving (STIT) or (LTIT) was compared, no marked differences were noted (39% vs 38%). However, there was a difference when the individual tumor risk features were compared, e.g. for solitary tumors, the recurrence rate was 67% within the (STIT) group and 43% within the (LTIT). These results demonstrate that the decision of whether superficial bladder carcinomas are to be treated with short- or long-term Epodyl should be based on tumor-associated risk factors. Furthermore, if multiple tumor risk factors are present, maximal therapy is require; in the absence of risk factors TUR alone may be sufficient.

Administration, Intravesical↗
PubMed1987

Morphological evidence for a direct innervation of the mouse vomeronasal glands.

The morphological evidence for a direct autonomic innervation of the mouse vomeronasal glands is presented. Axonal varicosities containing a few dense-core vesicles and numerous clear vesicles (36-60 nm in diameter) make synaptic contacts with the secretory cells at the base of the glandular acini. The axonal presynaptic membrane is associated with a distinct dense material and it is separated from the secretory cell by a synaptic cleft of about 12-14 nm. At the postsynaptical level, coated vesicles can be found. Additional postsynaptical specializations have not been observed.

Animals↗
PubMed1987

[A morphological study of the peri- and epineurium in the compression zone of the median nerve in carpal tunnel syndrome].

The structure of the peri- and epineurium of the median nerve in the carpal tunnel syndrome was studied by light and transmission electron microscopy. Electron microscopy confirms the flattened lamellar arrangement of the perineurial cells, but in contrast to the normal architecture the perineurial component of the median nerve in carpal tunnel syndrome consists of 20-25 layers of ramified squamous-type cells, each layer being separated from the adjacent one by a wide space containing thick bundles of collagen fibrils. The perineurial cells are bounded on both sides by a basement membrane which is of substantial thickness. A prominent feature is the occurrence of multiple pinocytotic vesicles and caveolae opening on both the internal and external aspects of the flattened cells. They also contain bundles of closely aggregated filaments. In the spaces between the perineurial cells we find, in some places, extremely disoriented and individually abnormal fibrils and fine filaments arranged in form of a spider web. Matrix vesicles can also be seen. The epineurium of the median nerve in the carpal tunnel syndrome is also considerably thickened, and the attachment is solid, so that the median nerve is relatively immobile constricted like an hourglass. The thick collagen fibers are orientated predominantly parallel to the axis of the nerve, but circular fibers can also be seen. Apart from fibroblasts, the outer layer of the epineurium contains mast cells and vasa nervorum as well as myelinated nervi nervorum. Variable quantities of fat are also present, particularly in the surrounding loose connective tissue.

Carpal Tunnel Syndrome↗