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K Krogh

Publications and source records attributed to K Krogh.

26 records · Page 2Linked to original sources
PubMed1999

Subcellular localization of GFP-myosin-V in live mouse melanocytes.

Class-V myosins are two-headed actin-based mechanoenzymes that function in the transport and subcellular localization of organelles and possibly in the outgrowth of cellular processes. To determine which domains of myosin-V are involved in intracellular localization of this motor protein, we have expressed fusions of the green fluorescent protein with segments from two distinct myosin-V heavy chains. The expression patterns of constructs encoding four different domains of chick brain myosin-Va were compared to a single construct encoding the globular tail region of mouse myosin-Vb. In transfected mouse melanocytes, expression of the NH(2)-terminal head (catalytic domain) of chick brain myosin-Va codistributed with actin filaments throughout the cytoplasm. A similar construct encoding the myosin-Va head with the associated neck (light chain binding sites), also codistributed with actin filaments. The GFP-head-neck peptide was also highly concentrated in the tips of filopodia in B16 melanocytes wild type for myosin-Va (MYO5a gene), but was concentrated throughout the entire filopodia of S91-6 melanocytes derived from dilute mice with mutations in the MYO5a gene. Evidence is also presented that the globular tail of myosin-Va, but not myosin-Vb, targets this motor molecule to the centrosome as confirmed by colocalization in cells stained with antibodies to (gamma)-tubulin. Expression of the GFP-myosin-Va globular tail causes displacement of endogenous myosin-V from centrosomes as visualized by immunolabeling with antibodies to the head domain of myosin-V. Treatment with the microtubule-disrupting drug nocodazole markedly reduces myosin-V staining at the centrosome. In contrast, there was no detectable diminution of myosin-V staining at the centrosome in cells treated with the actin filament-disrupting drug cytochalasin D. Thus, while localization of the myosin-V motor domain to actin-rich regions is consistent with conventional models of actomyosin-based motility, localization to the centrosome occurs in the complete absence of the myosin-V motor domain and is dependent on intact microtubules.

Actin Cytoskeleton↗
PubMed1998

Localization of myosin-V in the centrosome.

The perinuclear localization of myosin-V was investigated in a variety of cultured mammalian cells and in primary cultures of rat hippocampus. In all cells investigated, myosin-V immunoreactivity was associated with the centrosome. In interphase cells, myosin-V was found in pericentriolar material, and in both mother and daughter centrioles. These results were obtained by using two different fixation protocols with three different affinity-purified antibodies that recognized a single band in Western blots. During cell division, myosin-V staining was intense throughout the cytoplasm and was concentrated in a trail between migrating centrioles and in the mitotic spindle poles and spindle fibers. The centrosome targeting site was determined to reside within the globular tail domain, because centrosome association also was observed in living cells transfected with DNA encoding the tail domain fused with a green fluorescent protein tag, but not in cells transfected with the vector encoding green fluorescent protein by itself.

Animals↗
PubMed1998

Fracture rates and risk factors for fractures in patients with spinal cord injury.

AIM: To study fracture rates and risk factors for fractures in patients with spinal cord injuries. MATERIAL AND METHODS: A self-administered questionnaire was mailed to 646 members of the Danish Paraplegic Association and 1000 randomly selected normal controls. 438 patients (309 males, 129 females, 67.8%) and 654 controls (332 males, 322 females, 65.4%) returned the questionnaire. Median age in patients was 42, range 10-80 years, and in controls 43, range 19-93 years (2p = 0.25). RESULTS: The crude fracture rate was 2% per year in patients and 1% per year in controls (RR = 2.0, P < 0.001). Low-energy fractures were much more prominent in patients (19.0% of all fractures) than in controls (1.4%, P < 0.001). The fracture rate did not differ before the injury but increased after the injury to a constant level from the third year and forward. Fractures of the lower extremities were more prominent in patients than controls (femurs: RR = 23.4, P < 0.001, lower legs: RR = 5.2, P < 0.001, feet/toes: RR = 2.4, P = 0.006) while fractures of the forearms (P < 0.001) and clavicles (P = 0.03) were absent among patients. Fractures were more frequent in female patients (RR = 1.6, P = 0.008) and in male patients with a family history of fractures (RR = 2.0, P = 0.004). CONCLUSIONS: Low-energy fractures especially of the lower extremities are frequent in spinal cord injury patients and especially among female patients. The forearms seem protected from fractures.

Adolescent↗
PubMed1998

Malone antegrade continence enema for faecal incontinence and constipation in adults.

BACKGROUND: In the Malone antegrade continence enema (ACE) technique the appendix or a 'neoappendix' created from the caecum is brought to the abdominal wall creating a small stoma. Thereby, antegrade enemas can be administered to empty the colorectum and prevent faecal incontinence or constipation in children with congenital malformations. The aim of this study was to describe the results of the ACE in adults suffering from faecal incontinence or constipation. METHODS: In 16 adult patients (ten women and six men) suffering from severe faecal incontinence (ten patients) or constipation (six patients) the ACE procedure was performed; the appendix was used in 12 and a 'neoappendix' was created in four. Patient records were used for the description of surgical procedures and complications. Results were evaluated by a structured telephone interview. RESULTS: After a follow-up of 1-39 (mean 17) months, four patients had stopped using the stoma because of abdominal pain or lack of effect. Among the other 12 patients overall satisfaction with the stoma was high or very high. In constipated patients mean time for defaecation was reduced from 170 to 45 min. Faecal incontinence was much reduced in eight patients; the impact on social activities and quality of life caused by bowel dysfunction was reduced in all 12 patients. CONCLUSION: The ACE technique can be used to treat selected adult patients suffering from faecal incontinence or constipation.

Adult↗
PubMed1997

Colorectal function in patients with spinal cord lesions.

PURPOSE: This study was designed to describe the frequency and severity of colorectal problems among patients with spinal cord lesions and to determine whether these problems are associated with age, gender, time since the lesion, and level and severity of the lesion. PATIENTS AND METHODS: A detailed questionnaire describing colorectal and bladder function was sent to all 589 members of The Danish Paraplegic Association; 424 responded (72 percent). RESULTS: Only 19 percent felt a normal desire to defecate, whereas the remaining patients felt no desire to defecate (38 percent) or a combination of abdominal discomfort (37 percent) and headache, physical uneasiness, and perspiration (25 percent). Digital stimulation of the anal canal before defecation or digital evacuation of the rectum was used regularly by 65 percent of patients. Fecal incontinence was experienced by 75 percent of patients; however, most patients only had a few episodes of fecal incontinence each month (15 percent) or each year (56 percent). Overall, 39 percent of patients reported that colorectal dysfunction caused some or major restrictions on social activities or on their quality of life, and 30 percent regarded colorectal complaints to be worse than both bladder and sexual dysfunction. The severity of most symptoms was significantly correlated with the severity of the lesion, and the self-reported impact on social activities or quality of life was significantly more severe among women than men. CONCLUSION: Colorectal dysfunction is very common among spinal cord-injured patients, often causing restriction on social activities and quality of life. Therefore, these problems deserve more attention in the treatment of spinal cord-injured patients.

Adolescent↗
PubMed1997

Dimensions and mechanical properties of porcine aortic segments determined by combined impedance planimetry and high-frequency ultrasound.

The aim of the study is to devise a method for direct measurements of pressure, cross-sectional area (CSA) and wall thickness of a vessel when pressurised. Segments of porcine descending thoracic aorta from 22 and 35 kg pigs (in groups 1 and 2, respectively) and of abdominal aorta from 35 kg pigs are studied in vitro. Impedance planimetry provides measurements of the luminal pressure and CSA of the aorta. The wall thickness is measured simultaneously by means of 20 MHz A-mode ultrasound. The pressure, CSA and wall thickness are registered at different pressure at steady state. At maximum pressure, the CSAs are 107 +/- 10, 215 +/- 19 and 257 +/- 17 mm2 in the abdominal, group 1 and 2 segments, respectively. There is a difference between the abdominal group and groups 1 and 2 (p < 0.05), but not between group 1 and 2 segments (p > 0.2). At maximum pressure, the wall thickness is 0.52 +/- 0.04, 0.79 +/- 0.07 and 1.07 +/- 0.02 mm, in the abdominal group 1 and 2 segments, respectively (p < 0.05). The circumferential stress-strain relationship accorded well with stress = a x exp(b x strain). The stress-strain curve of the abdominal aortas is shifted to the left, indicating an increase (p < 0.05).

Animals↗
PubMed1996

Electroretinogram flicker photometry and its applications.

The electroretinogram (ERG) has been a traditional tool for the measurement and the analysis of spectral sensitivity. With the appropriate choices of stimulus and measurement conditions, the ERG permits a noninvasive examination of photopigment complement and provides the means for studying the combination of spectral signals at various locations throughout the retina. There are a number of practical problems associated with making spectral measurements with the ERG. One approach to minimizing these problems is to exploit the advantages of a flicker-photometric procedure. We summarize a method used to conduct ERG flicker photometry and illustrate a range of problems to which this technique can be successfully applied.

Electroretinography↗