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Biomedical subjects

W Back

Publications and source records attributed to W Back.

At least 19 recordsLinked to original sources
PubMed2006

Neonatal mastocytosis with pachydermic bullous skin without c-Kit 816 mutation.

BACKGROUND: Bullous mastocytosis is an unusual variant of mast cell disease with widespread bullae as the main cutaneous feature induced by mast cell proteases that cause dermoepidermal separation. CASE REPORT: A rare case of diffuse cutaneous bullous mastocytosis with pachydermia and unusually extensive skin folding is described in a 3-week-old girl. The diagnosis was confirmed by immunohistochemistry with Giemsa stain, the naphthol ASD chloroacetate esterase reaction and elevated blood levels for tryptase, histamine in serum and histamine and 1.4-methylimidazol acetic acid in the 24-hour urine. Blood cell count was normal, as were thrombocytosis and leukocytosis. FACS analysis of the bone marrow aspiration material showed 1% mast cells. No c-Kit 816 [Asp-->Val] somatic mutation was found. Systemic involvement of other organs was excluded. DISCUSSION: The prognosis of c-Kit-negative diffuse bullous mastocytosis is not known. Regular blood controls are mandatory, and screening for germ cell ovarian cancer and bone marrow controls should be performed as well.

Female↗
PubMed2006

Hoof growth between two shoeing sessions leads to a substantial increase of the moment about the distal, but not the proximal, interphalangeal joint.

REASONS FOR PERFORMING STUDY: There is little insight into the effects of routine farriery on the internal structures of the distal limb in sound horses. OBJECTIVES: To measure the effect of change in hoof conformation during a shoeing interval on the moments about the proximal and distal interphalangeal joints (PIPJ, DIPJ) and to determine whether and how the horse compensates for this change in hoof conformation. METHODS: Both front feet of 9 sound Warmblood horses were measured while standing on a pressure-force measuring system and radiographed in a lateromedial direction shortly after shoeing and 8 weeks later. From these data, ground reaction forces (GRF) and lever arms were measured in order to calculate joint moments. RESULTS: After 8 weeks, the moment about the PIPJ did not increase significantly, but the moment about the DIPJ did so, indicating a compensatory mechanism for a change in hoof conformation in the DIPJ. CONCLUSIONS: Standing horses compensate for hoof conformation change during an 8-week shoeing interval, which leads to increased DIPJ extension and consequently an increased loading of the deep digital flexor tendon. POTENTIAL RELEVANCE: This study quantifies the effect of a shoeing interval on the internal structures of the foot and helps to determine an appropriate shoeing interval for individual horses in which the hoof with the lowest hoof angle is the best indicator. The exact determination of an optimal individual shoeing interval requires further study.

Animals↗
PubMed2006

Shoeing sound warmblood horses with a rolled toe optimises hoof-unrollment and lowers peak loading during breakover.

REASONS FOR PERFORMING STUDY: Overload injuries in sport horses commonly occur; shoeing techniques are believed to be important in prevention of these injuries, but there is a paucity of scientific information identifying the potential connection. OBJECTIVES: To test a horseshoe with a modified rolled toe designed to ease the process of breakover and decrease loading of lesion-prone structures of the distal limb. METHODS: Twenty clinically sound Warmblood horses trotted over a track containing a pressure/force measuring system and 6 infrared cameras. The horses were measured with 2 types of shoes, standard flat shoes and shoes with a rolled toe. The shoeing procedure was randomised and horses had 2 days between measurements to adapt to the shoes. RESULTS: Limb placement and timing characteristics, e.g. breakover duration, did not change significantly. There was an improvement in the ease of movement to roll over the toe in the shoes with a rolled toe, due mainly to a smoother hoof-unrollment pattern. The peak indicative moment decreased substantially at the onset of breakover in the shoe with the rolled toe. CONCLUSIONS: With a rolled toe the process of hoof-unrollment is smoother, which improves the coordination of this process, and lowers peak loading of the distal limb during breakover. POTENTIAL RELEVANCE: This study stresses the importance of proper shoeing in sound horses, showing that shoe modifications can optimise the loading characteristics of the distal limb and therefore might be a means to prevent sport horses from overload injuries.

Animals↗
PubMed2006

Uneven feet in a foal may develop as a consequence of lateral grazing behaviour induced by conformational traits.

REASONS FOR PERFORMING STUDY: Conformational traits are important in breeding, since they may be indicative for performance ability and susceptibility to injuries. OBJECTIVES: To study whether certain desired conformational traits of foals are related to lateralised behaviour while foraging and to the development of uneven feet. METHODS: Twenty-four Warmblood foals, born and raised at the same location, were studied for a year. Foraging behaviour was observed by means of weekly 10 min scan-sampling for 8 h. A preference test (PT) was developed to serve as a standardised tool to determine laterality. The foals were evaluated at age 3, 15, 27 and 55 weeks. The PT and distal limb conformation were used to study the relation between overall body conformation, laterality and the development of uneven feet. Pressure measurements were used to determine the loading patterns under the feet. RESULTS: About 50% of the foals developed a significant preference to protract the same limb systematically while grazing, which resulted in uneven feet and subsequently uneven loading patterns. Foals with relatively long limbs and small heads were predisposed to develop laterality and, consequently unevenness. CONCLUSIONS: Conformational traits may stimulate the development of laterality and therefore indirectly cause uneven feet.

Aging↗
PubMed2006

Developmental aspects of distal limb conformation in the horse: the potential consequences of uneven feet in foals.

REASONS FOR PERFORMING STUDY: Distal limb conformation is generally accepted to be an important item with respect to performance and soundness in mature horses, but little is known about the developmental aspects. OBJECTIVES: To gain insight into the development of distal limb conformation and to assess the possible consequences of uneven feet in foals. METHODS: Conformation of the distal front limbs of 23 Warmblood foals was scored visually and measured using radiographs, at ages 27 and 55 weeks. At the same ages, pressure measurements were made under both front feet. RESULTS: At both ages the hoof-pastern axis was broken-backwards on radiographs, but only occasionally recognised as such, when scored by eye. Over time, the hoof angle decreased, while both the angles of the dorsal and solar surfaces of the distal phalanx (P3) increased and the parallelism between hoof wall and P3 improved. The foals with uneven feet at age 27 weeks showed a significant difference in distal limb loading that persisted until age 55 weeks. CONCLUSIONS: The alignment of the distal limb in the sagittal plane increased in a 6 month period. Visual assessment was not sensitive enough to appreciate this. The growth processes in the distal limb could not compensate for existing unevenness and ensuing asymmetrical limb loading. POTENTIAL RELEVANCE: Foals have a different conformation of the distal limb from mature horses, which should be taken into account when interpreting radiographs. Unevenness of the feet resulted in asymmetrical loading of the proximal and distal interphalangeal joint, which might lead to increased susceptibility to overload injuries and decreased performance at mature age.

Aging↗
PubMed2005

Saddle pressure measuring: validity, reliability and power to discriminate between different saddle-fits.

Saddle-fit is recognised as an important factor in the pathogenesis of back problems in horses and is empirically being evaluated by pressure measurements in clinical practice, although not much is known about the validity, reliability and usability of these devices in the equine field. This study was conducted to assess critically a pressure measurement system marketed for evaluating saddle fit. Validity was tested by calculating the correlation coefficient between total measured pressure and the weight of 28 different riders. Reliability and discriminative power with respect to different saddle fitting methods were evaluated in a highly standardised, paired measurement set-up in which saddle-fit was quantified by air-pressure values inside the panels of the saddle. Total pressures under the saddle correlated well with riders' weight. A large increase in over-day sensor variation was found. Within trial intra-class correlation coefficients (ICCs) were excellent, but the between trial ICCs varied from poor to excellent and the variation in total pressure was high. In saddles in which the fit was adjusted to individual asymmetries of the horse, the pressure measurement device was able to detect correctly air-pressure differences between the two panels in the back area of the saddle, but not in the front area. The device yielded valid results, but was only reliable in highly standardised conditions. The results question the indiscriminate use of current saddle pressure measurement devices for the quantitative assessment of saddle-fit under practical conditions and suggest that further technical improvement may be necessary.

Animal Husbandry↗
PubMed2005

[Equine exudative canker: an (auto-)immune disease?].

Equine canker is a chronic, hyperplastic, exudative pododermatitis affecting one or more feet. Although many causes and treatments have been suggested, the cause of the disease is still unknown and most probably multifactorial. Local treatments include radical surgical debridement of the diseased hoof tissue and application of caustic substances, antibiotics, and pressure bandaging. Nevertheless, the number of recurrences is high (45%). This article presents a 3-year-old New Forest pony-cross mare in which all horny structures (frogs, coronets, spurs, chestnuts) of all feet were affected. Bacteriological and fungal cultures of the frogs were found negative for the pathogens tested. Papilloma virus was not found. Clinical findings raised the hypothesis that the non-specific hyperplastic inflammation of these horn-like structures might have been caused by an (auto-)immune reaction. On the basis of the clinical findings, the pony was treated with surgical debridement of the frogs of a diagonal pair of feet and oral administration of prednisolone (1 mg/kg sid). The frogs, coronets, spurs, and chestnuts of all four feet healed completely within 8 weeks, thus making an (auto-)immune reaction more likely. In conclusion, this case report raised the hypothesis that an aspecific, hyperplastic inflammation of all four feet ('equine canker') and other horny structures may be caused by an (auto-)immune reaction, and that corticosteroids (prednisolone 1 mg/kg sid per os) are effective as treatment.

Animals↗
PubMed2005

Bronchioloalveolar carcinoma: a new cancer in Peutz-Jeghers syndrome.

Besides gastrointestinal hamartomatous polyposis and melanin spots in the skin and mucosa, patients with the Peutz-Jeghers syndrome (PJS) have repeatedly been observed with a variety of tumours, including lung cancer. Available data indicate an increased cancer risk among PJS patients, which suggests that the gene involved in PJS, STK11 on chromosome 19p13.3, may be a tumour suppressor gene. Herein, bronchioloalveolar carcinoma (BAC) of mucinous type is reported in a 22-year old male PJS patient with a novel germline frameshift insertion in exon 2 at codon 118 of the STK11 gene. Molecular studies of his BAC indicated loss of heterozygosity (LOH) in the region of STK11 on chromosome 19p13.3. This observation supports the hypothesis that STK11 is a tumour suppressor gene which is involved in the development of lung adenocarcinoma.

AMP-Activated Protein Kinase Kinases↗
PubMed2005

Changes in location of centre of pressure and hoof-unrollment pattern in relation to an 8-week shoeing interval in the horse.

REASONS FOR PERFORMING STUDY: In order to optimise shoeing and shoeing conditions, it is essential to know how the horse adapts to a common shoeing interval. OBJECTIVES: To measure changes in location of the centre of pressure (CoP) and hoof-unrollment pattern during a shoeing interval and to assess whether these changes in CoP result directly from changes in hoof conformation or are also influenced by compensatory mechanisms. METHODS: Eighteen horses were trotted over a pressure-force measurement system shortly after shoeing and 8 weeks later. The position of the CoP was measured and also predicted using calculations based on changes in hoof conformation. RESULTS: The measured shift in CoP was less than calculated. This difference was largest in the hind feet. The hoof-unrollment pattern stayed basically the same in the front feet, but in the hind feet there was a substantial lateral shift of the trajectory of the CoP. CONCLUSIONS: Horses can compensate, to a certain extent, for changes in hoof conformation that develop during 8 weeks on shoes. As the capacity to compensate is less in the forelimbs, the relative increase in loading of these limbs during a shoeing interval is larger than in the hindlimbs. POTENTIAL RELEVANCE: This study provides essential basic data for the development of science-based shoeing techniques.

Animals↗
PubMed2005

Frictional forces required for unrestrained locomotion in dairy cattle.

Most free-stall housing systems in the Netherlands are equipped with slatted or solid concrete floors with manure scrapers. A slipping incident occurs when the required coefficient of friction (RCOF) exceeds the coefficient of friction (COF) at the claw-floor interface. An experiment was conducted to measure ground reaction forces (GRF) of dairy cows (n = 9) performing various locomotory behaviors on a nonslippery rubber-covered concrete floor. The RCOF was determined as the ratio of the horizontal and vertical components of the GRF. It was shown that during straight walking and walking-a-curve, the RCOF reached values up to the COF, whereas for sudden stop-and-start responses, the RCOF reached values beyond the maximum COF that concrete floors can provide. Our results indicate that concrete floors do not provide enough friction to allow natural locomotory behavior and suggest that tractional properties of floors should be main design criteria in the development of better flooring surfaces for cattle.

Animals↗
PubMed2004

[Retrospective evaluation of surgical versus conservative treatment of keratomas in 41 lame horses (1995-2001)].

A keratoma is a rather uncommon disorder of the equine hoof that can lead to lameness. Few quantitative data exist about the prognosis of different treatment regimens. The outcome of 41 cases that were presented to the Department of Equine Sciences in the period 1995-2001 and that were treated according to different regimens was retrospectively evaluated. All horses showed lameness that could be attributed to the keratoma: 23 (56%) were treated surgically using a standardized procedure, while the other 18 (44%) were treated conservatively. Results were based upon 35 horses; 6 were lost to follow-up. Range of recovery time for the surgically treated patients, was 2-12 months and for the conservatively treated group 2 weeks to 6 months. Of the surgically treated patients 83% (n =23) returned to the same or higher performance level as before the onset of the lameness, as opposed to 42% (n = 12) of the conservatively treated horses (p<0.05). The average hospitalization period was significanty longer for the surgically treated patients (35 vs. 5 days, p<0.05). It is concluded that surgical excision of the keratoma is the preferred treatment for horses suffering from lameness caused by a keratoma, because the better outcome outweighs the longer hospitalization and the longer overall recovery time.

Animals↗
PubMed2004

Three-dimensional co-culture model of enterocytes and primary enteric neuronal tissue.

AIM: The aim of this study was to establish a three-dimensional model of the innervated mucosal barrier using a co-culture of an enterocyte cell line and enteric glial and nerve cells. Such a model might form the basis for further studies of interactions between the single compartments of the bowel wall, as well as of extrinsic influences on intestinal development and plasticity. METHODS: Isolated and dissociated myenteric plexus was resuspended in either collagen or extracellular matrix (ECM) solutions. After incubation at 37 degrees C the solution gelled and formed stable plugs where neurons and glial cells reaggregated to form secondary neuronal networks. HT-29-enterocytes were seeded on top of the gels either immediately (collagen, ECM), or after adding a thin layer of collagen II (ECM). RESULTS: While the neuronal tissue formed complex networks within the gel, the enterocytes on top of the gels grew differently depending on the substrate and innervation. So enterocytes on ECM gels did not grow to confluence, while on collagen gels or on ECM plus collagen larger patches and increasing confluence could be observed. In general HT-29 grew better on innervated gels than on gels with no neuronal tissue. CONCLUSIONS: With the presented model of different compartments of the bowel wall, various parameters of intercellular dependencies and influences can be observed in vitro. Moreover, the first results are also steps towards developing an innervated gut wall in vitro which might be able to restore functional capacity in infants with short bowel syndrome or other disorders that severely impair bowel function.

Animals↗
PubMed2004

Spontaneous malignant transformation of conventional giant cell tumor.

Spontaneous malignant transformation of conventional giant cell tumor (GCT) of bone is exceedingly rare. We report on a case of GCT of the iliac crest in a 35-year-old woman with malignant change into a high-grade osteosarcoma 10 years after the first appearance of GCT on a radiograph. Since the patient refused therapy for personal reasons the tumor remained untreated until sarcomatous transformation occurred. Image cytometry showed DNA aneuploidy and a suspiciously high 2c deviation index (2cDI) in the primary bone lesion. A thorough review of the world literature revealed only seven fully documented cases of secondary malignant GCT which matched the definition of a "sarcomatous growth that occurs at the site of a previously documented benign giant cell tumor" and not treated by radiotherapy. These cases as well as the current one suggest that a spontaneous secondary malignant GCT presents as a frankly sarcomatous tumor in the form of an osteosarcoma or malignant fibrous histiocytoma. It usually appears at sites of typical GCTs-often without any recurrent intermediate state-and is diagnosed 3 or more years after the primary bone lesion. The prognosis is poor.

Adult↗
PubMed2004

Dynamic pressure measurements for the detailed study of hoof balance: the effect of trimming.

REASONS FOR PERFORMING STUDY: Studies on hoof balance have, so far, only assessed the effects of strong and relatively unrealistic interventions due to technical limitations of measuring equipment. For the assessment of more subtle interventions, other techniques are necessary. OBJECTIVES: To test a sensitive pressure measurement system during locomotion and to set a standard for further studies by using the system to evaluate the effects of trimming. METHODS: Eighteen horses were measured before and after trimming with an interval of 4 weeks. Trimming was standardised to a straight hoof-pastern axis. The horses trotted over a pressure/force measuring system, with a temporal resolution of 240 Hz and a spatial resolution of 0.39 cm2. RESULTS: The preferred way of landing was lateral, asymmetrical in both front and hind feet. The duration of landing was shorter in forelimbs than in hindlimbs with an equal decreasing trimming effect. Horses had a fixed hoof-unrollment pattern; the centre of pressure (CoP) travelled towards a maximum lateral deviation and returned towards the dorsopalmar/plantar axis of the hoof. Trimming decreased the intra-individual left/right difference in maximum lateral displacement. CONCLUSIONS: The technique used provided easily accurate data to quantify hoof balance characteristics and to measure short-term trimming effects. POTENTIAL RELEVANCE: Determination of CoP patterns has added value in gait analysis and can improve our understanding of the effects of different interventions on hoof balance.

Animals↗
PubMed2004

Effects of girth, saddle and weight on movements of the horse.

REASONS FOR PERFORMING STUDY: Although the saddle is seen as one of the biggest causes of back pain, and weightbearing is seen as an important aetiological factor in 'kissing spine' syndrome (KSS), the effects of a saddle and weight on the back movements of the horse have never been studied. OBJECTIVE: To determine the effects of pressure on the back, exerted by tack and weight, on movements of the horse. HYPOTHESIS: Weight has an extending effect on the horse's back and, as a compensatory mechanism to this extension, an alteration in pro- and retraction angles was expected. A similar but smaller effect was expected from a saddle only and a lungeing girth. METHODS: Data were captured during treadmill locomotion at walk, trot and canter under 4 conditions: unloaded; with lungeing girth; saddle only; and saddle with 75 kg of weight. Data were expressed as maximal extension, maximal flexion angles, range of motion of L3 and L5 and maximal pro- and retraction angles of the limbs. RESULTS: At walk and trot, there was a significant influence on back kinematics in the 'saddle with weight' situation, but not in the other conditions. Overall extension of the back increased, but the range of movement remained the same. Limb kinematics changed in the sense that forelimb retraction increased. At canter, both the 'saddle with weight' and 'saddle only' conditions had a significant extending effect on the back, but there was no effect on limb kinematics. CONCLUSIONS AND POTENTIAL RELEVANCE: Weight and a saddle induce an overall extension of the back. This may contribute to soft tissue injuries and the KSS. The data from this study may help in understanding the reaction of the equine back to the challenges imposed by man when using the animal for riding.

Adaptation, Physiological↗
PubMed2004

The role of electromyography in clinical diagnosis of neuromuscular locomotor problems in the horse.

REASONS FOR PERFORMING STUDY: Systematically performed EMG needle examination of muscles provides essential information about the functional aspects of the motor unit. However, clinical studies in which information is given on the diagnostic and discriminative values of electromyography (EMG) in the horse are scarce. OBJECTIVES: To determine to what extent inclusion of EMG analysis in clinical examination contributes to determination of type and localisation of abnormality. METHODS: EMG analysis, complete clinical examination and diagnosis of 108 horses (mean +/- s.d. age 75 +/- 3.8 years; bodyweight 548 +/- 86 kg; height 1.67 +/- 0.07 m) were performed, and results without and with EMG analysis compared. RESULTS: Without EMG, myopathy and neuropathy were diagnosed in 20 and 58 horses, respectively, and with EMG in 17 and 82 horses. EMG changed localisation in myopathy and neuropathy in 12 and 37% of cases, respectively. Lesions in the C1-T2, T2-L3 and L3-S3 segments were, respectively, diagnosed without EMG in 7, 11 and 30%, and with EMG in 27, 7 and 17% of cases. Where no clinical diagnosis could be made prior to EMG, many patients appeared to be suffering from localised cervical lesions (29%) or generalised neuropathy (54%). CONCLUSIONS AND POTENTIAL RELEVANCE: The assistance of EMG in discriminating between normal, neuropathy and myopathy, and in locating pathology, contributes to diagnosis of neuromuscular problems.

Animals↗