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Biomedical subjects

D C Knottenbelt

Publications and source records attributed to D C Knottenbelt.

At least 19 recordsLinked to original sources
PubMed2003

Aid to the antemortem diagnosis of Fell pony foal syndrome by the analysis of B lymphocytes.

Fell pony foals are affected by a congenital fatal immunodeficiency that commonly leads to anaemia and lymphopenia. Previous work has shown that the foals' circulating subpopulations of CD4 and CD8 T lymphocytes are unaffected. In this study it was shown that the mean population of B lymphocytes in 10 affected foals was less than 10 per cent of that in normal foals.

Animals↗
PubMed2001

An immunodeficiency in Fell ponies: a preliminary study into cellular responses.

A putative immunodeficiency, causing mortality in UK Fell pony foals (Fell pony syndrome), was studied in affected foals and compared with healthy, age-matched foals. Differential cell counts of peripheral blood indicated that the syndrome foals were lymphopenic (P<0.05). Flow cytometric analysis of circulating leucocytes showed a reduced MHC II expression (P<0.01) on lymphocytes but not on polymorphonuclear cells in affected foals. There were no changes in the percentages of CD4+ or CD8+ T cells. There was an increased (P<0.05) expression of CD11a/18 by the lymphocytes of the syndrome foals, compared to the control foals, which is probably a response to systemic bacterial infections. The syndrome foals' lymphocytes responded to mitogens (PHA, ConA, PWM) at normal levels. The data do not conform to any known immunodeficiencies identified in any other species. Further analyses will be required, particularly on bone marrow function.

Age Factors↗
PubMed2000

Endoscopic electrosurgical excision of laryngeal granulation tissue in a standing pregnant mare.

An 11-year-old, eight-months pregnant mare suddenly developed severe respiratory distress. Endoscopic examination identified intralaryngeal granulation tissue obstructing the airway. In order to avoid general anaesthesia and the problems associated with a permanent tracheostomy, the mass was resected electrosurgically while the mare was standing. Patency was restored to the airway and the mare foaled without complication.

Airway Obstruction↗
PubMed2000

Headshaking in horses: possible aetiopathogenesis suggested by the results of diagnostic tests and several treatment regimes used in 20 cases.

Twenty mature horses with typical headshaking of 2 week-7 year duration were studied. Clinical examinations included radiography of the head and nasopharyngeal endoscopy. All were assessed at rest and at exercise, both before and after fitting an occlusive nasal mask, application of tinted contact lenses and the perineural anaesthesia of the infraorbital and posterior ethmoidal branches of the trigeminal nerve. Infraorbital anaesthesia had no effect in 6/7 cases but 11/17 (65%) cases showed a 90-100% improvement following posterior ethmoidal nerve anaesthesia. Tinted contact lenses had no apparent long-term benefit, although 2 cases showed a transient improvement. We found no other evidence to suggest a photic aetiology in the current series of cases. Treatment regimens based on the results of the diagnostic investigative methods included sclerosis of the posterior ethmoidal branch of the trigeminal nerve. This was effective in some cases but the benefits were temporary. Cyproheptadine alone was ineffective but the addition of carbamazepine resulted in 80-100% improvement in 80% of cases. Carbemazepine alone was effective in 88% of cases but results were unpredictable at predefined dose rates. The positive response to carbamazepine, combined with the clinical features is consistent with involvement of the trigeminal nerve, particularly the more proximal branches such as the posterior ethmoidal nerve. Headshaking has some clinical features in common with trigeminal neuralgia in humans. As a result of the findings detailed in this paper, we conclude that a trigeminal neuritis or neuralgia may be the basis of the underlying aetiopathology of equine headshaking. Initial observations of the positive response of headshakers to carbamazepine therapy is encouraging. However, future studies will include a more detailed investigation of dosages, duration of effectiveness (in some cases it appears short-lived) and other effects. In practice there is a realistic possibility of controlling but not curing headshaking with carbamazepine therapy at the present time. Other future investigations will include details of the functional anatomy of the trigeminal nerve and the role of the P2 myelin protein in headshaking and other neurological disease.

Anesthesia↗
PubMed2000

Anaemia, diarrhoea and opportunistic infections in Fell ponies.

This report summarises clinical and pathological observations on Fell pony foals with a range of signs that included ill thrift, anaemia, respiratory infection, glossal hyperkeratosis and diarrhoea. Some of the foals had normochromic, normocytic anaemia and some had low levels of plasma proteins, including immunoglobulin G. Antibiotic and supportive treatment was ineffective and all affected foals died or were killed on humane grounds. Postmortem examination of 12 foals and tissues from 2 other foals revealed a range of lesions that included glossal hyperkeratosis, typhlocolitis, intestinal cryptosporidiosis, granulomatous enteritis, proliferative and necrotising bronchiolitis consistent with adenovirus infection; lesions similar to those in the respiratory tract were present in the salivary gland and pancreas of individual foals. Lymphoid tissue was judged to be smaller than expected. These observations suggest the possibility of opportunistic infections secondary to some form of undefined immunocompromised state.

Anemia↗
PubMed1997

Surgical repair of the parotid gland in a gelding.

The surgical repair of a traumatic injury to the parotid (Stenson's) duct of an adult horse is described and compared with previous reports. The diagnosis was confirmed by the analysis of a flow of saliva-like fluid observed while the horse was eating. The repair was attempted under general anaesthesia three days after the injury. Surgical anastomosis was considered to have improved the rate of healing. However, there was some evidence of leakage of saliva from the site for three days after the removal of the in-dwelling catheter, seven days postoperatively. A full recovery followed.

Animals↗
PubMed1994

Humane destruction of horses with a mixture of quinalbarbitone and cinchocaine.

One hundred and-two horses requiring to be euthanased for a variety of reasons were killed by the intravenous injection of a mixture of quinalbarbitone sodium (400 mg/ml) and cinchocaine hydrochloride (25 mg/ml). The dose rates used were 1 ml/10, 15, 20 and 30 kg bodyweight, and the time of injection was varied between 5 and 25 seconds. The average time to collapse from the start of the injection was 34 seconds and the average time to clinical death was 230 seconds. Slow injection (particularly of the low dose rates) and premedication with detomidine resulted in a longer time to collapse (median 46 seconds). Premedication with xylazine and low dose rates of the mixture resulted in an unacceptable degree of muscular activity and agonal gasping and death was delayed. Premedication with romifidine and butorphanol resulted in an apparent (but insignificant) reduction in the time to collapse and death but was also accompanied by significant agonal gasping. Without premedication quinalbarbitone and cinchocaine resulted in a smooth and quiet collapse with the cessation of cardiac and respiratory functions within three minutes in all cases, but the palpebral reflex of the horses was prolonged significantly beyond the time when all other reflex activity was lost. Occasional gasping and muscular tremors, particularly of the upper forelimb, occurred particularly when lower dose rates and either very slow or very fast rates of injection were used. One horse which was premedicated with xylazine and received a very low dose at a slow rate showed unacceptably violent muscular activity. At no other time was the procedure regarded as violent or unacceptable.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Welfare↗
PubMed1993

Rhodococcus equi infection in foals: a report of an outbreak on a thoroughbred stud in Zimbabwe.

Twenty-four foals were confirmed to be infected with Rhodococcus equi on a private stud in Zimbabwe over a two-year period. Six mares had foals which were affected in each of the two years. All the foals were febrile and early cases were detected by this pyrexia. Bronchopneumonia was only clinically detectable in advanced cases. In spite of energetic hygiene measures relating to pasture and housing management, the incidence was higher in the second year (23 per cent of foals born) than in the first (15 per cent of foals born). The mean age of the foals was significantly greater in the second year. The immunological status of some of the foals was obtained from zinc sulphate turbidity tests performed at 24 hours old and all the affected foals so tested were considered to have had effective colostral transfer. Clinically, affected foals showed pyrexia, tachypnoea and tachycardia and many had a scanty purulent nasal discharge. Only one animal had diarrhoea which was attributed to enteric infection with R equi. Diagnosis was confirmed by clinical examination, culture of the organism from tracheal aspirates and thoracic radiography and was supported by significant elevations of plasma fibrinogen and platelet and neutrophil counts in all cases. Anaemia was not a major finding in any case. Rifampicin and erythromycin were administered per os and weight-related doses were continued until plasma fibrinogen and the absolute neutrophil and platelet counts had been persistently normal for two weeks. Supportive radiography was obtained in some cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Actinomycetales Infections↗
PubMed1992

Conservative treatment of oesophageal stricture in five foals.

Three foals under four weeks old and two under six months old with a history of oesophageal obstruction, had oesophageal strictures of different characters in the rostral cervical oesophagus. One case, which was complicated by severe inhalation pneumonia, was euthanased without any treatment and in another initial treatment by bougienage under general anaesthesia was attempted without success. The four surviving cases were provided with progressively firmer and coarser food, starting with liquid only, over a period of three to four weeks. The treatment is recommended in the early stages of stricture maturation and for strictures which do not involve the deeper layers of the oesophageal wall.

Age Factors↗
PubMed1992

Reproduction in female cattle in a communal farming area of Zimbabwe.

Cattle in a communal farming area of Zimbabwe were identified and examined in the late dry and mid wet season of 1985/86. Ovarian activity rates were 17.9% and 38.6% in the dry and wet season respectively. Pregnancy rates were 16.1% and 24.6% respectively. A major limitation to reproduction was the percentage of anoestrous females. There was no evidence of a seasonal calving pattern. Median body condition score was 2.0 in the dry season and 1.5 in the wet season. Adult females of body condition score 2.5 and above had ovarian activity rates of 41.9% and pregnancy rates of 41.9 per cent. Those with a body condition score below 2.5 had rates of 26.8% and 16.4% respectively. Serum progesterone levels in pregnant animals were positively related to body condition score, with some animals having progesterone levels similar to non-pregnant animals. Metabolic profiles suggested that the major limiting nutrient in both seasons was nitrogen, although other micronutrients might also be involved in low reproductive rates.

Agriculture↗