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Biomedical subjects

G Müller

Publications and source records attributed to G Müller.

At least 361 records · Page 20Linked to original sources
PubMed1991

Reaction time prolongation in the early stage of presenile onset Alzheimer's disease.

Simple reaction times (RT) to clicks, flashes and numerical signals were measured in four groups of subjects: 21 patients with mild presenile onset dementia of the Alzheimer type (PDAT, mean age 56 years), 14 patients with chronic cardiovascular disease and incipient cognitive deficit (mean age 55 years), 15 healthy older controls (mean age 53 years) and 16 younger controls (mean age 23 years). Both patient groups had significantly prolonged RTs, the PDAT group especially to the numerical signal (149%), compared with the age-matched controls.

Adult↗
PubMed1991

Impaired eye tracking performance in patients with presenile onset dementia.

Smooth pursuit eye movements, saccades and eye blinks were electrooculographically recorded from 26 healthy subjects of different age and 35 patients with presumptive presenile onset dementia (mean age 54), who had to track a light spot which oscillated with different speeds. Older subjects (mean age 51) performed the eye tracking with less accuracy and more saccades than younger ones (mean age 22). 16 patients with stage CDR 1 according to Washington University Clinical Dementia Rating performed smooth pursuit eye movements significantly worse with increased saccade numbers than the healthy older subjects and lost attention significantly more often which was measured by omitted trackings to presented target oscillations. Their number of eye blinks was partly increased. The test is found suitable for early diagnosis of dementia onset, supporting clinical findings and presumptive diagnosis by objective parameters.

Aging↗
PubMed1991

[Sonographic findings in radiologically non-displaced proximal humerus fractures].

UNLABELLED: In 5 patients with radiological nondisplaced fracture of the proximal humerus and persistent pain of the involved shoulder joint, ultrasonic evaluation was performed statically and dynamically. All patients suffered from a nondisplaced two-part fracture of the greater tuberosity. In four cases we found a significant cranialisation of the greater tuberosity between 1 and 8 mm. Furthermore, we identified a ventral cleft on the fracture side as well as a dorsal dislocation of the fragment. During dynamic examination we observed an impingement of the supraspinatus tendon between the acromion and the greater tuberosity. CLINICAL RELEVANCE: In primary diagnosis of cases with a questionable dislocated fragment and in patients with persistent pain after proximal humeral head fractures, diagnostic ultrasound investigation may yield additional information. This may influence further treatment.

Adult↗
PubMed1991

[Microendoscopy of the Eustachian tube and the middle ear. Indications and clinical application].

Progressive miniaturization of flexible fibreoptic systems has made it possible for the first time to perform atraumatic endoscopy of the Eustachian tube and tympanic cavity with the ear drum intact. With the aid of special actively steerable microcatheters, flexible fibrescopes having outer diameters of 350 to 650 microns are inserted into the opening of the naso-pharyngeal tube and advanced into the tympanic cavity under direct visual control. This new technique is indicated for any disturbance of sound conduction and in those sensorineural hearing disorders in which direct inspection of the middle ear cavity can provide information on the pathogenesis of the disturbance. In the future it may thus replace purely diagnostic tympanoscopy. In combination with fibre-delivery laser systems, this new method forms the basis of "microendoscopically controlled laser surgery" of pathological changes within this anatomical region.

Ear, Middle↗
PubMed1991

[Variance, factors of influence and clinical relevance of plasma viscosity].

The problem of measuring plasma viscosity has been solved through the use of capillary and falling-ball viscosimeters which have a determination variance of less than 1%. On account of the influence of overeating, forced thirst, psychological and physical stress plasma viscosity should be determined in the morning; the patient should be fasting and well hydrated. Plasma viscosity is influenced by diseases with alterated plasma protein composition. An elevated viscosity also significantly increases the risk of developing an arterial occlusion. Since the physician can both decrease and increase plasma viscosity, it should be determined parallel to therapy. Accordingly, plasma viscosity is one of the most important rheological parameters.

Adult↗
PubMed1991

Duration of EEG alpha wave blockade by tone stimulation is prolonged in early stage of presenile onset dementia of the Alzheimer type.

The EEG alpha rhythm suppression by sudden unexpected tones in a relaxed wakefulness state (Berger response) was measured in four groups of patients and healthy control subjects. One patient group with early cognitive deficits probably caused by a mild stage of presenile onset primary degenerative dementia of the Alzheimer type (DAT), a second patient group with cardiovascular disease and a stage of questionable dementia, an age-matched group of older healthy control subjects and a younger control group. Only half of the DAT group in the mild stage had significantly prolonged Berger responses and a retarded or disturbed habituation. In agreement with other data of their cognitive deficits this indicated a weakening in focussing attention and selective inhibition.

Acoustic Stimulation↗
PubMed1991

Structure and function of lamellar bodies, lipid-protein complexes involved in storage and secretion of cellular lipids.

This review article attempts to present an overview of the occurrence and function of lipid storage and secretory organelles: the lamellar bodies. Morphologically these organelles vary considerably in size (100 nm to 2400 nm); they are surrounded by a membrane and contain multilamellar lipid membranes. Lamellar bodies may also contain apolipoproteins and lytic enzymes and have an acidic pH, which confers on them a lysosomal character. Under normal physiological conditions, the main function of lamellar bodies is the supply of extracellular domains with specialized lipid components related to a specialized function. The lamellar bodies of the lung epithelium are best investigated in their functional and structural features and are the storage form of the lung surfactant. They provide a monomolecular lipid film of dipalmitoyl phosphatidylcholine (DPPC) on the surface of lung alveoli to lower surface tension necessary for optimal gas exchange and a hydrophobic protective lining against environmental influences. Additional cells of the respiratory system such as the mucosa of the human nose and the bronchi contain lamellar bodies. Lamellar bodies are also found in the gastrointestinal tract, in tongue papillae, oral epithelium, and mucosa cells of the stomach. The major phospholipid of lamellar bodies in mucosa cells of the stomach is DPPC, providing a hydrophobic protective lipid film against the tissue-damaging activities of gastric juice. The hydrophobic water-protective barrier of the skin, which consists mainly of neutral lipids, however, also originates from lamellar bodies secreted by epithelial cells. Lamellar bodies, mainly consisting of DPPC, also occur in mesodermal cell layers of sliding surfaces to provide the lubrication of joints, of the peritoneum, pericardium, and pleural mesothelium. In certain pathological conditions, such as atherosclerosis, Niemann-Pick disease, lecithin:cholesterol acyltransferase (LCAT) deficiency, cholestasis, degeneration of nerves and brain, and regeneration of nerves and wound healing, lipid-containing lamellar bodies have been observed in various cells, the function of which still remains to be elucidated. In early and late lesions of atherosclerotic plaques, lamellar bodies, consisting of unesterified cholesterol and phospholipids, are associated with the extracellular matrix of the intima. During regression of fatty streaks, lamellar bodies are seen intracellularly in macrophages and smooth muscle cells. Inherited metabolic disorders, such as Niemann-Pick disease type I and type II, result in the excessive accumulation of lamellar body-containing cells, for example in bone marrow, spleen, and lymphoid tissue. Type I is a deficiency in sphingomyelinase and type II is a defect in intracellular trafficking of lipoprotein-derived cholesterol.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

[Improved model of a fecal collection device for the prevention of coprophagia in the rat].

Previous fecal collection cups with tape fixation frequently led to serious necroses of the rat tail due to strangulations, and did not allow for growth of the tail. A recently developed new model gives space for rapidly growing tails and is securely fixed by a cannula perforating both fecal collection cup and tail. It is transparent, cheap to be made, and easy to empty and was tested in 118 animals for two and four weeks. In no case the cup did loosen or had to be removed due to infections, strangulations or any local problems.

Animals↗
PubMed1991

Lesion of pontine micturition area in rat causes a severe kidney syndrome.

Bilateral symmetric lesions of a small strip in the dorsal pontine reticular formation between the locus coeruleus and the laterodorsal tegmental nucleus caused a severe disturbance of kidney and urinary bladder function beginning with haematuria, micturition paralysis and incontinence on the second postoperative day. Thirteen rats with these lesions were killed on the sixth postoperative day, dissectioned and their kidneys were pathomorphologically investigated. Their urinary bladders were extremely expanded and filled with bloody urine. All kidneys showed a picture of hydronephrosis and were enlarged from 15 mm preoperatively to 30 mm in their longitudinal axis and from 9 to 15 mm in their transverse axis. In seven further rats with partial or asymmetric lesions of this pontine micturition area the micturition cessation and the haematuria disappeared between the 4th and 8th postoperative days: kidney enlargement and hydronephrosis were still found on the 20th postoperative day.

Animals↗
PubMed1991

Incisor growth acceleration after lesions in the lateral pontine reticular formation of rats.

The length of upper and lower incisors of Long-Evans hooded rats between gingiva and top were measured before and after small bilateral symmetric electrolytic lesions of the pontine reticular formation between the ventromedial parabrachial nucleus and the motor trigeminal nucleus. Ten days after lesions of this region 8.5 mm posterior to bregma the length of upper incisors was 13.4 +/- 0.7 mm compared with 6.1 +/- 0.2 mm before lesion (p less than 0.01) and the length of the lower incisors 17.1 +/- 0.4 mm compared with 10.2 +/- 0.2 mm before lesion (p less than 0.01). A second group with a smaller lesion of this region 9.0 mm posterior to bregma reached upper incisor length of 13.2 +/- 0.4 mm (p less than 0.05) and lower incisor length of 14.7 +/- 0.5 mm (p less than 0.05) at the 20th postoperative day. Sham-operated controls had no tooth growth acceleration.

Animals↗
PubMed1991

[Postoperative monitoring of transplanted kidneys using color Doppler sonography].

In 52 renal transplant patients a prospective study was carried out to compare the validity of szintigraphy and color-duplex-sonography for demonstrating the renal blood flow. In 49 cases the questions bout intra-allograft blood flow could be answered. In two cases szintigraphy was unable to make a right evidence. Angiodynography is a non invasive method to demonstrate the blood flow in renal allografts and is able to replace the szintigraphy.

Blood Flow Velocity↗
PubMed1990

The human pregnancy-specific glycoprotein genes are tightly linked on the long arm of chromosome 19 and are coordinately expressed.

The pregnancy-specific glycoprotein (PSG) genes encode a group of proteins which are found in large amounts in placenta and maternal serum. In situ hybridization analyses of metaphase chromosomes reveal that all the human pregnancy-specific glycoprotein (PSG) genes are located on the long arm of chromosome 19 (19q13.2-13.3), overlapping the region containing the closely-related carcinoembryonic antigen (CEA) gene subgroup. Higher resolution analyses indicate that the PSG genes are closely linked within an 800kb SacII restriction endonuclease fragment. This has been confirmed through restriction endonuclease mapping and DNA sequence analyses of isolated genomic clones, which show that at least some of these genes are located in very close proximity. Further, these studies have helped to identify a new member of the PSG gene subfamily (PSG7). DNA/RNA hybridization analyses, using gene-specific oligonucleotide probes based on published sequences, showed that five from six PSG genes tested are coordinately transcribed in the placenta. Due to the close proximity of these genes and their coordinated expression pattern, common transcriptional regulatory elements may exist.

Base Sequence↗
PubMed1990

[Structure and function of the factor VIII/von Willebrand factor complex].

In the blood plasma factor VIII is bound to the von Willebrand factor. The primary structure of the two proteins were clarified by gene clonation. Factor VIII descends from a precursor protein with 2,351 amino acids by splitting of 19 amino acid residues and is activated by partial proteolysis. In the blood coagulation factor VIII acts as co-factor for the activation of factor X by factor IX in the presence of phospholipids and Ca++ within the intrinsic coagulation system. The formation of the von Willebrand factor takes place by splitting of 22 and 741 amino acid residues, respectively, from pre-pro-von Willebrand factor via pro-von Willebrand factor. The subunits of the von Willebrand factor consist od 2,050 amino acid residues. In the blood plasma the von Willebrand factor is existing as a mixture of multimeres. Receptors of the von Willebrand factor on the thrombocytic membrane are the glycoproteins GPIb and GPIIb/GPIIIa, by means of which the adhesion of thrombocytes at the subendoethelium of the vascular wall and the aggregation of thrombocytes are mediated.

Amino Acids↗
PubMed1990

Rescue of the albino phenotype by introduction of a functional tyrosinase gene into mice.

The c-locus of the mouse is thought to encode tyrosinase, the key enzyme for melanin synthesis in melanocytes of the skin and the eye. Recently, a mouse cDNA was isolated and shown to confer tyrosine activity on a cell line which expressed no specialized functions for melanin synthesis. To verify that the isolated tyrosinase gene is encoded at the genetically well characterized c-locus, a minigene was assembled from tyrosinase cDNA and tyrosinase genomic DNA and used for generation of transgenic mice. Following microinjection of this construct into fertilized eggs of an albino mouse strain, transgenic mice were obtained which showed pigmentation in skin and eyes. By in situ hybridization, we show expression of the transgene in melanocytes of the hairbulb and in the pigmented cell layers of the eye. We conclude that we have rescued the albino mutation (c/c) by introduction and expression of a functional tyrosinase gene.

Albinism↗