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Biomedical subjects

P E Davis

Publications and source records attributed to P E Davis.

At least 19 recordsLinked to original sources
PubMed2002

Neuropsychological deficits and opiate abuse.

Cognitive functioning was examined in people with a current or past history of opiate abuse using a range of neuropsychological tests. Sixty percent of those currently abusing opiates showed impairments of at least two standard deviations from the published norms on two or more neuropsychological tests, a significantly higher incidence than found in matched controls with no history of drug abuse. The drug free group of recovering addicts fell between the other groups without significant differences. It was concluded that the risk of neuropsychological impairment is greater in opiate abusers, and that recovery may occur during abstinence.

Adult↗
PubMed1999

Disseminated Mycobacterium genavense infection in a FIV-positive cat.

An 8-year-old FIV-positive Australian cat was presented with coughing, periocular alopecia, pyrexia and inappetence. Skin scrapings demonstrated Demodex cati mites. Antibiotics were administered and it was treated successfully for periocular demodectic mange, but the cat continued to exhibit respiratory signs and lose weight. Further investigation revealed an ascarid infection and active chronic inflammation of undetected cause affecting the lower airways. Repetitive treatment with pyrantel failed to eradicate the ascarid infection. The cat became cachectic and developed moist ulcerative dermatitis of the neck, severe non-regenerative anaemia, leucopenia and thrombocytopenia. Necropsy and histopathology revealed mycobacteriosis affecting skin, lungs, spleen, lymph nodes, liver and kidney. Attempted culture of frozen tissues at a mycobacteria reference laboratory was unsuccessful. Paraffin-embedded, formalin-fixed tissue was retrieved and examined using PCR to amplify part of the 16S rRNA gene. A diagnosis of disseminated Mycobacterium genavense infection was made based on the presence of acid fast bacteria in many tissues and partial sequence of the 16S rRNA gene. Although M genavense has been identified previously as a cause of disseminated disease in AIDS patients, this is the first report of infection in a cat. It was suspected that the demodecosis, recurrent ascarid infections and disseminated M genavense infection resulted from an immune deficiency syndrome consequent to longstanding FIV infection.

Animals↗
PubMed1999

Technical note: use of slow-release estradiol and prostaglandin F2alpha to induce pseudopregnancy and control estrus in gilts.

We determined whether a single injection of slow-release estradiol-17beta (SRE2) would induce pseudopregnancy in gilts and whether PGF2alpha would regress the corpora lutea (CL) of pseudopregnancy. Crossbred gilts (n = 40) were induced to ovulate by treatment with 400 IU of hCG + 200 IU of eCG (PG600, Intervet, Millsboro, DE) given at 180 d of age (d = 0). On d 14, gilts were injected i.m. with one of five doses (n = 8 gilts/dose) of SRE2 (0, 12.5, 25, 50, or 100 mg). Blood samples were collected before SRE2 and twice weekly until d 73 to monitor serum progesterone (P4) and estradiol (E2). On d 59, gilts received (i.m.) 10 mg of PGF2alpha (Lutalyse, Pharmacia Upjohn, Kalamazoo, MI) and were checked for estrus for 7 d. On d 62, mammary development was scored (0 = no development; 1 = some development; 2 = teat and gland development) by a neutral observer. Treatment with SRE2 increased (P < .05) peak E2 concentrations, duration of luteal function, and mammary gland score. There were no differences (chi-square, P > .05) among doses of SRE2 in the percentage of pseudopregnant gilts that showed luteolysis after PGF2alpha. We conclude that a single injection of SRE2 can induce pseudopregnancy and that the CL can be regressed with PGF2alpha, providing a simple method for controlling estrus in gilts.

Animals↗
PubMed1997

Rickets in a litter of racing greyhounds.

Rickets was diagnosed in six 14-week-old racing greyhound littermates presented with musculoskeletal disease. Physical findings included listlessness, profound muscle weakness, lameness, lateral bowing of the antebrachii and focal hard swellings proximal to the tarsi and carpi. Radiological findings included generalised osteopenia, axial and radial thickening of growth plates, and "cupping' of the adjacent metaphyses; the distal ulnar growth plates were most severely and consistently affected. The diagnosis was confirmed by demonstrating subnormal concentrations of 25-hydroxycholecalciferol in serum samples collected at admission. The pups' diet consisted of an inexpensive generic kibble formulated for adult dogs, porridge, milk, pasta, minced beef, vegetables and a small quantity of calcium carbonate powder. The pups were successfully treated by feeding a nutritionally complete, vitamin D-containing ration formulated for growing pups. Bilateral growth retardation of distal ulnar physes occurred as a sequel in one pup.

Animals↗
PubMed1996

Interrogative suggestibility in opiate users.

The present study investigated interrogative suggestibility in opiate users. A group of patients undergoing a methadone detoxification programme in an in-patient drug treatment unit (Detox group, n = 21), and a group of residents who had come off drugs and were no longer suffering from withdrawal syndrome (Rehab group, n = 19) were compared on interrogative suggestibility and various other psychological factors. Significant differences were found between the two groups, with the Detox group having more physical and psychological problems, and a higher total suggestibility score in comparison with the Rehab group. These findings are discussed in relation to the context of police interrogations and the reliability of confessions made by suspects and witnesses dependent on opiates.

Adult↗
PubMed1990

An analysis of the abstinence violation effect in a sample of illicit drug users.

Studies using samples of alcoholics and cigarette smokers show that the occurrence of the abstinence violation effect predicts the likelihood of a full-blown relapse following an initial slip from voluntary abstinence. The present study investigated this process in a sample of 31 illicit drug users. The attributional styles of abstainers and relapsers were examined in addition to the types of initial slip situations for the relapse group. No significant differences were found in attributional styles, although relative to the relapse group there was a tendency for abstainers to score higher on internality and stability of attribution for negative events, but lower on globality. Both negative affect and interpersonal conflict, but not social pressure, were found to be important precipitants for relapse. Demographic differences between the groups are discussed in addition to the implications of the results for models of relapse, prediction of relapse and cognitive therapy in relapse prevention.

Adolescent↗
PubMed1990

Fibrosis of gastric cardia after endoscopic sclerosis. Mechanism for control of experimental reflux?

Endoscopic sclerosis of the gastric cardia (ESGC) prevents experimental gastroesophageal reflux (GER) without changes in lower esophageal sphincter (LES) pressure and length. This study was performed to define the histologic appearance of the esophagus and stomach one year after ESGC. Four dogs were studied one year after ESGC with morrhuate sodium; ESGC had been performed at six sites, 1-3 cm distal to the esophagogastric junction. All animals had stable weight and eating habits at sacrifice. Light microscopy of the cardia and LES included morphometry of wall thickness (mm) and assessment of fibrosis (- to ). The esophagus had minimal changes; the gastric cardia had focal fibrosis, maximal on the greater curve, without any change difference in wall thickness. ESGC results in fibrosis of the gastric cardia, without significant changes in the esophagus. These changes prevent GER, possibly by preventing the initiation of a reflux event.

Animals↗
PubMed1989

Hematologic, biochemical, blood-gas, and acid-base values in greyhounds before and after exercise.

After racing 722 m, 16 Greyhounds were evaluated to determine changes in hematologic, biochemical, blood-gas, and acid-base values following exercise. Values were determined before racing (T0), immediately after racing (T1), and 3 hours after racing (T2). Significant changes detected immediately after racing included increased heart rate, respiratory rate, and rectal temperature. Significant changes in hematologic values included increases in PCV, total plasma protein, hemoglobin, RBC, WBC, neutrophils, and lymphocytes. Change was not detected in values for monocytes, eosinophils, and neutrophil/lymphocyte ratio. Other increases included those for plasma concentrations of sodium, chloride, calcium, lactic acid, aspartate transaminase, alanine transaminase, alkaline phosphatase, creatine kinase, lactate dehydrogenase, and glucose. Concentrations of potassium and urea did not change. Measurement of blood-gas and acid-base status revealed significant increases in PaO2 and base deficit, whereas PaCO2, pH, and bicarbonate decreased. Three hours after exercise, all vital signs and blood-gas and acid-base values, except for PaCO2, which was still slightly low, had returned to baseline (T0) values. Most biochemical values had also returned to baseline, although sodium, chloride, aspartate transaminase, and creatine kinase were still high, and urea was low. Many hematologic values were still different from baseline values, with high values for WBC, neutrophils and neutrophil/lymphocyte ratio, and low values for PCV, total plasma protein, hemoglobin, RBC, and lymphocytes.

Animals↗
PubMed1984

Cued recall and the nature of the memory disorder in dementia.

The study investigated the retrieval deficit hypothesis of forgetting in senile dementia, using a cued recall technique. Memory for lists of words was tested with either no cues given at the time of recall, or alternatively by cueing the patient either with the word's first letter or its semantic category. Results do not support a retrieval deficit explanation of forgetting in dementia, but instead suggest the possibility of a processing deficit at the acquisition stage.

Aged↗
PubMed1981

Fixation of metacarpal and metatarsal fractures in greyhounds.

Over a 6-year period a total of 23 greyhounds and 10 dogs of other breeds were presented with metacarpal and metatarsal fractures. While in other breeds trauma was the usual cause, in greyhounds the injuries were stress or fatigue fractures. In the greyhounds the fractures occurred mainly in young dogs and were often comminuted. Fifteen cases involved the fifth metacarpal bone of the left foreleg. The fractures were managed by either external immobilisation (8 cases) or internal fixation, mainly with lag screws (14 cases). Of 16 dogs which recovered sufficiently to be trialled, 6 were retired due to poor performance, 2 suffered further fractures and 4 raced in less than 10 races each. Four dogs entered in more than 10 races each won 23 of a total of 109 starts.

Animals↗
PubMed1980

The production of alpha-amylase in batch and chemostat culture by Bacillus stearothermophilus.

The production of alpha-amylase (alpha-1,4-glucan 4-glucanohydrolase; EC 3.2.1.1) by a strain of Bacillus stearothermophilus isolated from leaf litter was investigated in a tryptone-maltose medium at 55 degrees C in batch and chemostat culture. Amylase production was growth-limited and restricted to the exponential phase in batch culture. The enzyme yield was reduced by 40% when the culture pH was maintained at pH 7.2. Amylase production in chemostat culture was influenced by the growth rate throughout the dilution rate range used.

Amylases↗
PubMed1979

Heterogeneity of chloramine T- and lactoperoxidase-radioiodinated human calcitonin.

Radioiodination reportedly damages peptides, but the nature of the damage has not been adequately examined. Utilizing isoelectric focusing, we examined the products of Chloramine T- and lactoperoxidase-directed radioiodinations of human calcitonin. Initially, the reaction products were purified by adsorption onto and elution from microfine silica (QUSO-G32). Radioiodination of the calcitonin by Chloramine T and lactoperoxidase produced a heterogeneous population of 125I-labeled peptides exhibiting apparent isoelectric points that were more acidic than that of unlabeled synthetic calcitonin. Variation in the products among radioiodinations and the inability of QUSO-G32 to resolve the components of the reaction mixture prompted our examination of alternative purification procedures. Anion-exchange chromatography on QAE-Sephadex effectively separated [125I]diiodotyrosine containing calcitonin from free iodine and [125I]iodolactoperoxidase. Our data indicate that: (a) radioiodination of human calcitonin by Chloramine T and lactoperoxidase induced alteration in the peptide as evidenced by isoelectric point, (b) specific [125I]iodopeptides vary in incidence and relative abundance among radioiodinations, (c) identification of the labeled amino acid in [125I]iodopeptides cannot ensure intergrity of the molecule, and (d) isoelectric focusing provides a method of comparing the products of peptide radioiodinations among laboratories.

Calcitonin↗
PubMed1978

The use of electrocardiography in the diagnosis of poor racing performance in the horse.

Electrocardiograms were reocrded from 153 racehorses and 10 Olympic three-day-event horses. The horses were then grouped into those presented for routine examination, those in which there was a complaint of poor performance, those going to the Montreal Olympics, and those with upper respiratory tract abnormalities. When the ECGs of the four groups were compared on the basis of detection of abnormality, it was found that 93.2% of the poor performance group showed abnormalities of various types. The routine examination group showed 21.1% of horses with abnormal ECGs, and over half of these have been followed to the point where it can be said they raced unsuccessfully. In particular, this applied to those horses with T wave abnormalities in 4 or more leads, and to those with intraatrial block. There were significant T wave changes in 50% of the Olympic horses, and 43.7% of horses with laryngeal hemiplegia showed abnormality. While it can be concluded that T wave changes are highly significant findings in an ECG, it is also true that modification of the training programme is a way of helping trainers to get the best out of horses which might otherwise have a serious limitation of their performance potential.

Animals↗
PubMed1977

Paroxysmal atrial fibrillation in a racehorse.

A 4-year-old thoroughbred stallion with a history of loss of racing form was studied over a period of approximately 7 months. At the initial examination he showed positive T waves in 1 chest lead and wandering of the pacemaker. This was followed by an episode of paroxysmal atrial fibrillation which disappeared spontaneously and was replaced by significant T wave changes in all the chest leads. During a period when these changes persisted, there was progressive lengthening of the P wave and the P-R interval. Because the last ECG showed evidence of intra-atrial block, first degree A-V block and T wave changes, the owner was advised that a fluctuating myocarditis was affecting the horse's performance and it was retired to stud. This appears to be the first report of paroxysmal atrial fibrillation in Australia, and it demonstrates the value of regular follow-up examinations in horses with initial electrocardiographs showing only minor departures from normal. The case also suggests that when sharp reversals of racing form occur, the possibility of paroxysmal atrial fibrillation being the cause should be kept in mind.

Animals↗