Biomedical subjects

V Schubert

Publications and source records attributed to V Schubert.

17 recordsLinked to original sources

PubMed2006

Nuclear DNA content and nuclear and cell volume are positively correlated in angiosperms.

Volumes of flow sorted nuclei were analyzed from two highly endopolyploid (diploids with endopolyploid tissues) species (Arabidopsis thaliana and Barbarea stricta), from a less endopolyploid species (Allium cepa) and from two non-endopolyploid species (Chrysanthemum multicolor and Fritillaria uva-vulpis). Intraspecific as well as interspecific comparisons revealed a highly positive correlation (r > 0.99) between DNA content and nuclear volume. No significant differences between expected and measured nuclear volumes were noted indicating that chromatin packing is not increased with increasing DNA content in the tested plant species. In epidermis cells of A. thaliana, A. cepa and Ch. multicolor, a lower (r between 0.6 and 0.7) but significant positive correlation between nuclear volume and cell volume was found. This correlation is compatible with the hypothesis that endopolyploidization (EP = consecutive replication cycles not separated by nuclear and cell divisions) might speed up the growth of endopolyploid species and compensate for small genome size.

Arabidopsis↗

PubMed2004

DNA damage processing and aberration formation in plants.

Various types of DNA damage, induced by endo- and exogenous genotoxic impacts, may become processed into structural chromosome changes such as sister chromatid exchanges (SCEs) and chromosomal aberrations. Chromosomal aberrations occur preferentially within heterochromatic regions composed mainly of repetitive sequences. Most of the preclastogenic damage is correctly repaired by different repair mechanisms. For instance, after N-methyl-N-nitrosourea treatment one SCE is formed per >40,000 and one chromatid-type aberration per approximately 25 million primarily induced O6-methylguanine residues in Vicia faba. Double-strand breaks (DSBs) apparently represent the critical lesions for the generation of chromosome structural changes by erroneous reciprocal recombination repair. Usually two DSBs have to interact in cis or trans to form a chromosomal aberration. Indirect evidence is at hand for plants indicating that chromatid-type aberrations mediated by S phase-dependent mutagens are generated by post-replication (mis)repair of DSBs resulting from (rare) interference of repair and replication processes at the sites of lesions, mainly within repetitive sequences of heterochromatic regions. The proportion of DSBs yielding structural changes via misrepair has still to be established when DSBs, induced at predetermined positions, can be quantified and related to the number of SCEs and chromosomal aberrations that appear at these loci after DSB induction. Recording the degree of association of homologous chromosome territories (by chromosome painting) and of punctual homologous pairing frequency along these territories during and after mutagen treatment of wild-type versus hyperrecombination mutants of Arabidopsis thaliana, it will be elucidated as to what extent the interphase arrangement of chromosome territories becomes modified by critical lesions and contributes to homologous reciprocal recombination. This paper reviews the state of the art with respect to DNA damage processing in the course of aberration formation and the interphase arrangement of homologous chromosome territories as a structural prerequisite for homologous rearrangements in plants.

Arabidopsis↗

PubMed2001

The effects of light therapy on mini-mental state examination scores in demented patients.

BACKGROUND: Preliminary evidence suggests that demented patients may experience beneficial effects of light therapy. The authors tested whether bright light therapy (BLT) is capable of improving cognitive functions in patients with Alzheimer-type dementia (AD) or vascular dementia (VD). METHODS: Twenty-three patients with AD or VD were randomly assigned to either evening BLT or dim light therapy (DLT). Effects of light therapy on cognitive functions were assessed before and after light therapy using Mini-Mental State Examination (MMSE) scores. Body temperature rhythm (BTR) was additionally recorded pre- and posttreatment. RESULTS: Irrespective of their diagnosis, patients treated with BLT (p =.0012) but not with DLT (p =.73) showed a statistically significant increase in MMSE total scores after light therapy. Evening BLT simultaneously induced a significant phase delay of 56 min on BTR (p =.025). CONCLUSION: Our preliminary results suggest that short-term evening BLT may exert beneficial effects on cognitive functioning in patients with dementia.

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PubMed2001

Effects of phototherapy on pressure ulcer healing in elderly patients after a falling trauma. A prospective, randomized, controlled study.

BACKGROUND: The effects of infrared and red pulsed monochromatic light, with varied pulsations and wavelengths, on the healing of pressure ulcers were evaluated in this prospective, randomized, controlled study. METHODS: Elderly patients (> or =65 years) with Stage 2 or 3 skin ulcers were enrolled and assigned to one of two groups. Both groups were given the same standard ulcer therapy. One group was also given phototherapy with pulsed monochromatic infrared (956 nm) and red (637 nm) light. Treatments lasted 9 min each time using a regimen with pulse repetition frequency varied between 15.6 Hz and 8.58 kHz. Patients were followed for 10 weeks or until the ulcer was healed, whichever occurred first. The ulcer surface area was traced weekly. RESULTS: Patients treated with pulsed monochromatic light had a 49% higher ulcer healing rate, and a shorter time to 50% and to 90% ulcer closure compared with controls. Their mean ulcer area was reduced to 10% after 5 weeks compared with 9 weeks for the controls. CONCLUSION: The results are encouraging as pulsed monochromatic light increased healing rate and shortened healing time. This will positively affect the quality of life in elderly patients with pressure ulcer.

Accidental Falls↗

PubMed2000

The influence of local heating on skin microcirculation in pressure ulcers, monitored by a combined laser Doppler and transcutaneous oxygen tension probe.

In a prospective, controlled study the skin microcirculation and transcutaneous oxygen tension were evaluated in 28 elderly patients (85 +/- 0.8 years) with grade 2 and 3 pressure ulcer. Laser Doppler fluxmetry and transcutaneous oxymetry techniques were used together in a combined probe to simultaneously evaluate the influence of heat stress at 44 degrees C, at the same time and in the same area of the ulcer edge. Total skin microcirculation was already increased at rest before heating, and increased even more during a fast and then a more gradually heat-induced hyperaemia response compared with undamaged skin. The increase showed a biphasic manner. On the other hand, the oxygen diffusibility from the capillaries to the skin surface was significantly reduced, compared with undamaged skin. One hypothesis may be that in ageing skin the main part of the increased skin microcirculation in a pressure ulcer were passing through thermoregulatory vessels in subpapillary tissue layers. Interactions between the increased blood flow and metabolic activity at the ulcer edge might be oxygen-consuming, leading to reduced oxygen content passing through the capillaries and contributing to tissue ischaemia. Disturbances of the local skin microcirculation and tissue oxygenation will influence the ulcer healing rate and may affect the healing progress.

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PubMed1997

[Letting family participate in care. A study on relatives' experience with a palliative geriatric care department].

An evaluation was made of relatives' experiences of the care of the patient and the treatment of themselves at a geriatric ward where elderly patients dying of cancer were nursed. A questionnaire was sent to 100 relatives after they had agreed on telephone to participate. 86 relatives answered the questions. The results shows that the majority of the relatives were satisfied with the care of the patient and the treatment of themselves as relatives. Most of them thought that they had been able to influence the care of their next-to-kin. However, elderly ladies and younger men were uncertain whether they had had the possibility to influence the care. Most of the relatives had been given the opportunity to talk enough to the doctor, the nurses and the social-worker. However; they required a more active approach from the staff in the ward. They also desired more information about the patient's disease, prognosis and medical treatment. The findings of this study suggest that relatives need information repeated at several occasions in order to understand the message. They also need support and invitation to get the courage to ask questions and to participate in the care of their dying next-of-kin. We need deepen our knowledge of what kind of information the relatives demands and what information needs to be repeated. Evaluations of routines to make contact easier between patients, their relatives and hospital staff should be done continuously.

Adult↗

PubMed1995

Analysis of arterial flowmotion in spinal cord injured and elderly subjects in an area at risk for the development of pressure sores.

Flowmotion (blood flow changes due to vasomotion) in the skin over a risk area for pressure sores, the sacrum, and a non-risk area, the gluteus muscle, was evaluated by laser Doppler fluxmetry during resting conditions and post-occlusive reactive hyperaemia (PRH) response. Measurements were made in healthy younger subjects and in two risk groups for pressure sores-spinal cord injured (SCI) and the elderly. The SCI were divided into two subgroups, one with and one without distinct flowmotion seen on the original recordings over the sacrum. The Prony spectral line estimation (PSLE) method was used to determine the power spectrum of the flowmotion activity. During the PRH, flowmotion frequencies were found in two separated bands, 5.4-6.6 cpm (cycles min-1) and 7.8-9.0 cpm. In the subgroup without distinct flowmotion, the PSLE method found flowmotion frequencies similar to the other groups. During the PRH, the flowmotion power pattern over the sacrum was similar within all groups, but the power was extremely low in one subgroup of SCI subjects. To conclude, flowmotion (vasomotion) was present in the two skin areas and increased during the PRH response, reaching a maximum within 50 s. This study shows that the flowmotion frequencies might be locally driven, whereas the power might be centrally mediated. Disturbances in microcirculatory flowmotion can be a part of the mechanisms leading to skin ischaemia and pressure sores. A new method has been developed for analysing differences in flowmotion behaviour such that statistical comparisons can be made.

Adult↗

PubMed1994

The effects of pressure and shear on skin microcirculation in elderly stroke patients lying in supine or semi-recumbent positions.

The effects of external pressure and shear on the skin microcirculation over the sacral area, which is known as a high risk area for pressure sore formation, were studied in 30 elderly patients. The skin blood cell flux (SBF) was measured using the laser Doppler technique, with the patient first at rest in lateral position, then lying for 30 minutes in supine or semi-recumbent 45 degrees position, and finally in lateral position. Elderly high-risk patients (G2), most of them more than two years post-stroke, had a lower body mass index and a reduced sacral skin-fold compared with non-risk patients (G1). The SBF in G2 decreased 28% in supine and 14% in 45 degrees position, whereas the SBF in G1 increased 35% in supine and 13% in 45 degrees position. Spontaneous movements up to seven times per 30 minutes were registered, even during sleep, and were evident by direct observation of the recorded charts as a temporary SBF increase. The risk for skin ischaemic damage over the sacral area of elderly risk patients was evident in both positions, especially with the patients lying in supine position. When increasing the upper body slope in G2 from horizontal to 45 degrees, an inability to recover a satisfactory blood supply after the ischaemic insult was found. Discomfort from compressive and shear forces initiates changes in posture, even in elderly patients prone to tissue breakdown. Occasional relief of pressure was in most patients followed by temporary increase in skin blood flow with concomitant temperature increase. This most probably protected them from developing skin lesions.

Aged↗

PubMed1994

Skin microcirculatory and thermal changes in elderly subjects with early stage of pressure sores.

Elderly subjects are prone to develop pressure sores over the sacrum area mainly due to external pressure and shear effects which negatively affect the skin microcirculation. The aim of the study described here was to measure skin microcirculatory and thermal changes in twelve elderly patients with an early stage of pressure sore and in ten elderly subjects without pressure sore. The total skin microcirculation at a damaged risk area, the sacrum, and a reference area of undamaged skin over the gluteal region, was evaluated using the laser Doppler fluxmetry. The nutritive transport of small solutes, characterized by the transcapillary exchange of sodium fluorescein, was evaluated using the fluorescein flowmetry technique. The skin temperature was measured with a thermoelement. The skin microcirculation at the area with an early stage of pressure sore was significantly higher than at undamaged skin as measured by both techniques. The total microcirculatory blood flow increased > 16 times (P < 0.001) and the nutritive transport approximately 5 times (P < 0.01) compared to the reference value, and the calculated blood flow of subpapillary tissue layers increased 17-19 times (P < 0.001). However, the skin temperatures in damaged and undamaged skin did not differ significantly. These results show an increased skin microcirculation in the early stage of pressure sores but no increase in skin temperature. The more strongly increased skin blood flow in subpapillary tissue layers effectively conducts away the heat caused by the damage and the increased metabolic activity.

Aged↗

PubMed1992

Repeated DNA sequences of Aegilops markgrafii (Greuter) Hammer var. markgrafii: cloning, sequencing and analysis of distribution in Poaceae species.

Total DNA of Aegilops markgrafii (Greuter) Hammer var. markgrafii was shot gun cloned. From all the recombinants containing repetitive sequences 1-2% hybridized preferentially with the Ae. markgrafii genome and were almost absent in wheat. The cloned sequences are disperse distributed over the Aegilops chromosomes and show the typical features of eukaryotic repetitive DNA. Five specific probes were tested for their applicability in a screening program on 68 Poaceae accessions.

Base Sequence↗

PubMed1991

Hypotension as a risk factor for the development of pressure sores in elderly subjects.

The systolic (sBP), diastolic (dBP) and mean (mBP) blood pressure were measured in hospitalized geriatric patients with (n = 30) and without (n = 100) pressure sores. A more intensive investigation was carried out in 18 elderly hospitalized geriatric patients without pressure sores, who were compared with 10 healthy young and 10 healthy elderly subjects. In these groups, the blood pressure was compared to the skin blood cell flux (SBF) as evaluated by the laser Doppler technique, at rest and during the post-occlusive reactive hyperaemia (PRH) response in the sacral area which is a high risk area for pressure sores. The patients with pressure sores had a significantly lower sBP (130 +/- 17 mmHg) compared to patients without pressure sores (140 +/- 20 mmHg). A significant correlation between a low resting SBF and a low mBP was found in all groups. An impaired PRH response corresponded to a low sBP in the two elderly groups. No correlation to dBP was seen at all. It is concluded that low mBP and sBP in elderly hospitalized patients were significantly correlated to a low resting SBF and a impaired reactivity of the skin microcirculation, respectively, and a low sBP was associated with pressure sores. Measurements of the systemic BP are of importance when classifying patients at risk of pressure sores.

Aged↗

PubMed1991

Evaluation of the dynamic cutaneous post-ischaemic hyperaemia and thermal response in elderly subjects and in an area at risk for pressure sores.

The response of skin blood cell flux (SBF) to locally applied pressure was evaluated with the laser-Doppler technique in the areas of the sacrum and the gluteus maximus muscle of geriatric patients and healthy young and elderly subjects. The SBF over the sacrum stopped at a lower external skin pressure than over the gluteus muscle in all groups studied (P less than 0.05-0.001). The SBF at rest was lower among geriatric patients and over the sacrum, with men showing the lowest value (P less than 0.001). The initial slope of the SBF curve and the peak SBF during the post-occlusive reactive hyperaemia (PRH) were lower among geriatric patients compared to younger healthy subjects (P less than 0.05-0.01) over both areas studied. During the last part of the PRH response rhythmic oscillations started, known as vasomotion. The mean skin temperature at rest was higher over the sacrum (P less than 0.001) than over the gluteus area, but no difference was found between the groups. The temperature increase during the PRH was larger over the gluteus muscle (P less than 0.01) than over the sacrum area in the healthy subjects. Among the patients the temperature increase was larger over the gluteus only during the first half of the PRH, after which the temperature increased most over the sacrum. It is concluded that SBF and skin temperature show different responses in microvascular reactivity to external pressure in elderly vs. younger subjects and also between sexes. The described technique may be useful in clinical practice for predicting the risk of pressure sores in different areas and subjects.

Adult↗

PubMed1991

Postocclusive reactive hyperemia and thermal response in the skin microcirculation of subjects with spinal cord injury.

The response of skin blood cell flux (SBF) to locally applied pressure was evaluated by laser Doppler fluxmetry over the sacrum and the gluteus maximus muscle in twenty patients with spinal cord injuries (SCI)-ten with tetraplegia, ten with paraplegia-and ten healthy subjects. The SCI patients were further divided into two subgroups, one with sensation and the other without sensation over the sacrum area. The SBF over the sacrum, without applied pressure, showed somewhat higher values among the patients. The ten paraplegic patients (p less than 0.05) and the subgroup of patients without sensation over the sacrum (p less than 0.05) showed the highest values. Occlusion of the SBF was reached at a lower external skin pressure over the sacrum than over the gluteus maximus muscle in the group with spinal cord injuries (p less than 0.01). During the postocclusive reactive hyperemia we found a much shorter time to peak SBF over the gluteus muscle for the patients compared to the healthy subjects (p less than 0.01). In the subgroup of patients without sensation over the sacrum a prolonged time to peak SBF was found (p less than 0.01) over the sacrum compared to patients with sensation and to healthy subjects. The increase of the SBF during postocclusive hyperemia response was lower over both the sacrum and the gluteus maximus muscle areas in the patients with spinal cord injuries (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1989

Local skin pressure and its effects on skin microcirculation as evaluated by laser-Doppler fluxmetry.

The effect of prolonged local pressure on the skin microcirculation was investigated in the regions of the sacrum and gluteus maximus muscle to determine the aetiology of pressure sores. Thirty normal subjects (15 female, 15 male) were investigated. The subjects were divided into three age groups: group 1, less than or equal to 35 years; group 2, 36-64 years; and group 3, greater than or equal to 65 years. Local pressure was applied with a specially designed instrument according to the sequence 0----110----0----110----0----mmHg. Skin blood cell flux (SBF) was measured with a laser-Doppler technique and the local skin temperature measured with a thermistor. No significant differences were seen in SBF due to sex or age. However, differences between the two areas studied were observed. SBF was maximal over the sacrum at 12-50 mmHg (1.6-6.7 kPa) applied pressure. With further pressure increases, the SBF signal decreased successively, reaching minimum level at 110 mmHg (14.6 kPa), where it was approximately 43% below the initial value. The SBF in the gluteus region showed a more stable pattern, with a maximum SBF at 13-60 mmHg (1.7-8.0 kPa). At both locations, an increased SBF at zero pressure was seen when the pressure was decreased from 110 to 0 mmHg. The skin temperature (n = 7) increased by 2.7 degrees C (range 1.9-3.5 degrees C) over the gluteus and by 1.3 degrees C (range 0.8-2.5 degrees C) over the sacrum. This increase was more rapid over the gluteus region. Concomitantly a temperature-dependent increase of SBF could be seen. It is concluded that a cause for the greater frequency of pressure sores over the sacrum than over the gluteus region is the comparatively poorer regulation of microvascular flow in this area.

Adult↗

PubMed1989

[Urinary protein level determination as a rapid method for the detection of contamination of slaughtered swine].

Reference is made to work undertaken by Stehle (1983) on rapid semiquantitative determination of urinary protein in pigs for slaughter to identify premortal strain and stress, with additional studies being conducted into the suitability of the method. The investigations performed for this study covered urinary protein samples from 59 living and 762 slaughtered pigs. The Biophan E paper strip test was applied to groups of animals, and, when compared to high-accuracy laboratory determination of urinary protein, it provided sufficiently accurate information on the presence of stress-related proteinuria. Its accuracy, however, proved to be insufficient, when individual animals were examined. The number of clearly stressed slaughter pigs was unexpectedly high, although the same animals had been rated clinically inconspicuous prior to slaughter. Brief rest period resulted in significant rise of stress. The Biophan E paper strip test was found to be suitable for instantaneous determination of stress and strain on pigs for slaughter.

Animals↗

PubMed1982

Malignant mesothelioma in Turkish immigrants residing in Sweden.

Mesothelioma is a rare neoplasm in the general population, but it is strongly associated with previous asbestos exposure. The endemic occurrence of this disease in two villages in central Turkey has raised the question of whether the inhalation of naturally occurring zeolite dust may also be a factor in the development of mesothelioma. During the past few years a large portion of the inhabitants of one of the two villages of concern has immigrated to Sweden. This report presents three cases of malignant pleural mesothelioma and the results of a chest radiographic survey among these immigrants. Mineralogical analysis of lung tissue specimens from two of the cases revealed the presence of both zeolite and asbestos minerals and therefore suggested a synergistic effect involving both types of minerals. The importance of close medical surveillance of this high-risk population is emphasized, as is the possibility that similar cases appear in other countries because of increased migration.

Adult↗

PubMedDate not supplied

Analysis of the measurement of four wound variables in elderly patients with pressure ulcers.

The suitability of four different methods for measuring pressure ulcer size was investigated during 10 consecutive weeks in a group of 11 elderly patients. The methods used were: 1. Volume measurement by filling the wound cavity with a gel 2. area measurement, by tracing the wound boundary outlined on transparent film with a digital planimeter 3. perimeter measurement, by tracing the wound boundary outlined on transparent film with a digital measuring pen 4. depth measurement using a millimeter probe. The mean values of the rate parameters for volume, area, perimeter, and depth were approximately in the proportions 3:2:1:1, which mirrors the inherent geometric dimensions of the corresponding variables. The methods used for measuring perimeter and depth were less reliable than the methods used for measuring volume and area. Thus, the use of both volume and area measurements in recommended. The former is best suited for deep ulcers and the latter for broad, irregularly shaped ulcers.

Aged↗