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Biomedical subjects

J Bird

Publications and source records attributed to J Bird.

At least 37 records · Page 2Linked to original sources
PubMed1998

Dung-derived biological agents associated with reduced numbers of infective larvae of equine strongyles in faecal cultures.

Two sets of dung-derived organisms from soil routinely fertilized with manure (MA) and soil chemically fertilized (CH) were cultured separately in the laboratory. Baermannized organisms from these cultures were added to 20 g of faeces from strongyle-infected horses to form three treatment groups: (i) no soil organisms; (ii) low inoculum of soil organisms containing all organisms present in a suspension of approximately 100 adult female free-living nematodes; and (iii) high inoculum containing those soil organisms present with approximately 1000 adult female free-living nematodes. Three studies were conducted using MA cultures and faeces containing 50 stronglye epg, CH cultures and faeces containing 1500 strongyle epg, and a mixture of soil organisms from the two cultures (MC) and faeces containing 600 strongyle epg. Within each study, five control cultures and 15 each of low and high inoculum cultures were prepared and incubated at 24 degrees C and 95% humidity in a climate chamber for 15 days. Parasitic and free-living nematodes were then recovered by the Baermann technique and counted. The numbers of third stage larvae were significantly lower in the high inoculum group compared to controls. The percent reductions in the number of third stage larvae for the low and high inoculum groups were 63.6% and 90.9%, 85.1% and 97.1%, 84.5% and 98.4% for MA, CH, and MC studies, respectively, indicating that mortality increased with the number of soil organisms added to cultures. Examination of the source cultures detected the presence of two species of nematophagous fungi and three genera of free-living nematodes reported to be predacious.

Animals↗
PubMed1998

Luteinizing hormone and human chorionic gonadotropin decrease type 2 5 alpha-reductase and androgen receptor protein levels in women's skin.

The present study tested the hypothesis that LH/hCG may regulate the type 2 5 alpha-reductase and androgen receptor protein levels in skin. The skin samples obtained from women undergoing abdominal laparotomy or abdominoplasty were incubated in the presence or absence of hCG. Western blotting was then performed to determine the response of type 2 5 alpha-reductase and androgen receptors. The results demonstrated that treatment with hCG resulted in a significant time- and dose-dependent, although modest, decrease in 5 alpha-reductase and androgen receptor levels compared to the controls. These effects were mimicked by LH, but not by other hormones in the glycoprotein hormone family, including alpha- and beta-subunits of hCG. Although the biological and clinical importance of this regulation remains to be determined, these findings reaffirm that human skin is among the nongonadal tissues that respond to LH and hCG treatment.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1998

Heat resistance of Salmonella weltevreden in low-moisture environments.

The heat resistance of Salmonella weltevreden inoculated into flour and heated in hot air was determined for (a) an initial water activity (aw) range of 0.20 to 0.60 prior to heating, (b) a range of storage relative humidities of 6.0 to 35.5% prior to heating, and (c) temperatures of 57 to 77 degrees C. The death curves obtained were biphasic, demonstrating an initial rapid decline in the numbers of survivors (1.0- to 1.5-log reductions) during the first 5 to 10 min of heating for all the temperature-water activity combinations tested. Following this initial rapid decline in the number of cells, a linear survivor curve was obtained where inactivation occurred at a slower rate. The initial decline in survivors coincided with a rapid decrease in the water activity of all the samples tested. Irrespective of the initial water activity level in the samples prior to heating, the aw decreased to < 0.2 during the first 5 to 10 min of heating. The D values obtained for these experimental parameters ranged from a D60-62 of 875 min at an initial aw of 0.4 to a D63-65 of 29 min at an initial aw of 0.5. The results demonstrated that, for any temperature, as the initial water activity of the sample prior to heating decreased, the heat resistance of the cells increased. The z values obtained from these data ranged from 15.2 to 53.9 degrees C. The relative humidity during storage prior to heating did not appear to have a significant effect on the heat resistance of S. weltevreden in flour. These results demonstrate that the amount of available water in foods that are considered to be "dry" (i.e., with a water activity less than 0.60) will significantly influence the effectiveness of the heat processing of foods and, in addition to the temperature, the aw prior to heating is a critical controlling factor during these processes.

Food Microbiology↗
PubMed1995

Characterization and distribution of esterase electromorphs in the whitefly, Bemisia tabaci (Genn.) (Homoptera: Aleyrodidae).

Esterase profiles were examined for over 40 populations of the whitefly, Bemisia tabaci, obtained from native and cultivated plant hosts worldwide. Twelve unique electromorphs were identified from distinct populations concentrated largely in Central America, Africa, and India. One electromorph, type B, has recently been proposed as a separated species, Bemisia argentifolii, and has recently spread throughout much of the world. When considered with evidence from mating studies and the ability to induce phytotoxic disorders (squash silverleaf disorder), our data suggest that the single taxon Bemisia tabaci may actually represent a species complex.

Alleles↗
PubMed1995

Relationship between balance system function and agoraphobic avoidance.

There is a striking similarity between the situations avoided by people with agoraphobia and the environments which provoke disorientation in people with organic balance disorders. This study investigated the possibility that agoraphobia might be linked to balance system dysfunction by comparing the results of balance system tests in 36 people with symptoms of panic and agoraphobia and 20 normal controls. A traditional battery of audiovestibular tests was supplemented with moving platform posturography, which assesses the postural instability induced by disorienting perceptual conditions. Subjects also completed questionnaire measures of somatic symptoms of dizziness and anxiety, agoraphobic cognitions, avoidance behaviour and state anxiety. Over 60% of the Ss with symptoms of panic and agoraphobia were destabilised by the disorienting perceptual conditions, compared with just 10% of the normal controls. Postural instability was strongly related to reported agoraphobic avoidance (r = 0.63, P < 0.01), even after controlling for symptoms, anxiety and agoraphobic cognitions. In our discussion we consider alternative interpretations of these findings, future directions for research, and implications for therapy.

Adult↗
PubMed1995

In vitro assessment of two species of nematophagous fungi (Arthrobotrys oligospora and Arthrobotrys flagrans) to control the development of infective cyathostome larvae from naturally infected horses.

The ability of two species of nematophagous fungi, Arthrobotrys oligospora and Arthrobotrys flagrans (syn. Trichothecium flagrans, Duddingtonia flagrans), to control the development of infective larvae in feces from naturally infected horses was assessed in vitro. The horses were from a farm where it had been previously established that cyathostomes accounted for 100% of the strongyle egg output. The feces from these naturally infected horses were mixed with spores of each fungal species at four concentrations: 0 (control), 1, 10, and 100 spores per egg. Five replicates for each group were incubated for 8 days. Infective larvae were harvested using a Baermann technique and counted. The percentage reduction in infective cyathostome larvae was calculated for each fungal concentration compared to controls. A fungal concentration of 1 spore per egg resulted in 40.5% and 32.1% reduction for A. oligospora and A. flagrans, respectively. A concentration of 10 spores per egg resulted in 87.4% and 90.5% reduction, while 100 spores per egg resulted in 95.8% and 93.9% reduction for A. oligospora and A. flagrans, respectively.

Animals↗
PubMed1995

Phonological awareness and literacy development in children with expressive phonological impairments.

This study investigated the link between expressive phonological impairments, phonological awareness, and literacy. Previous investigations of literacy skills in children with speech impairments have given mixed results; here we considered whether presence of additional language impairments or severity of the speech impairment was an important prognostic factor. Thirty-one children with expressive phonological impairments were compared with control children matched on age and nonverbal ability on three occasions, at mean ages of 70, 79, and 91 months. On each occasion they were given three tests of phonological awareness: one involved rime-matching and two involved onset-matching. At assessments 2 and 3 literacy skills were assessed. Children with phonological impairments scored well below their controls on phonological awareness and literacy, independent of whether or not they had other language problems. Although many of them knew letter sounds, they were poor at reading and writing nonwords as well as real words. It is suggested that both the speech impairment and the literacy problems arise from a failure to analyze syllables into smaller phonological units. The severity of the phonological problems in relation to age is an important determinant of literacy outcome; children who have severe expressive phonological impairments at the time they start school are at particular risk for reading and spelling problems.

Age Factors↗
PubMed1995

Effects of anxiety arousal and mental stress on the vestibulo-ocular reflex.

Although the subjective reports of patients suggest that anxiety may aggravate vertigo and imbalance, there has been little research into how anxiety might directly affect balance system functioning. We conducted two studies to examine the effect of anxiety and arousal on the vestibulo-ocular reflex (VOR). In the first study, pre-lest fear ratings were obtained from 20 normal subjects and 36 anxious subjects immediately prior to rotation and caloric testing. Fear ratings were significantly correlated with the maximum slow-phase velocity (SPV) of nystagmus induced by caloric testing. In the second study, we assessed the VOR response to rotation of 36 normal subjects under 3 task conditions: a) minimal alerting (counting backwards during rotation), b) physical arousal (induced by exertion prior to rotation); c) mental arousal (induced by performance of stressful mental tasks during rotation). Both the physical and mental tasks induced a significant increase in heart rate compared with the alerting condition. The maximum SPV of the nystagmus induced by rotation was significantly greater during performance of the mental task than in the other two conditions. These combined results indicate that anxiety may influence the gain of the VOR.

Adolescent↗
PubMed1994

Synthesis of novel N-phosphonoalkyl dipeptide inhibitors of human collagenase.

The synthesis of a series of N-phosphonalkyl dipeptides 6 is described. Syntheses were devised that allowed the preparation of single diastereoisomers and the assignment of stereochemistry. The compounds were evaluated in vitro for their ability to inhibit the degradation of radiolabeled collagen by purified human lung fibroblast collagenase. Several of the compounds were potent collagenase inhibitors and were at least 10-fold more potent than their corresponding N-carboxyalkyl analogues. Activity was lost when the phosphonic acid group P(O)(OH)2 was replaced by the phosphinic acid groups P(O)(H)(OH) and P(O)(Me)(OH). At the P1 position, (R)- or (S)-alkyl groups, especially ethyl and methyl (e.g., 12a,b, 52a,b, and 53a,b), or an (R)-phenethyl moiety (55a) conferred high potency (IC50 values in the range 0.23-0.47 microM). (S)-Stereochemistry was preferred for the P1' isobutyl side chain. Structure-activity relationships were also investigated at the P2' site, and interestingly, compounds with basic side chains, such as the guanidine 57a, were equipotent with more lipophilic compounds, such as 52a. As with other series of collagenase inhibitors, potency was enhanced by introducing bicyclic aromatic P2' substituents. The most potent phosphonic acid of the series was the bicyclic aromatic P2' tryptophan analogue 59a (IC50 0.05 microM).

Animals↗
PubMed1993

Synthesis of novel modified dipeptide inhibitors of human collagenase: beta-mercapto carboxylic acid derivatives.

The synthesis of a series of thiol-containing, modified dipeptide inhibitors (8) of human collagenase, which incorporate various carboxylic acid derivatives at the presumed P1 position, beta to the thiol group, is described. The compounds were evaluated, in vitro, for their ability to inhibit the degradation of rat skin type 1 collagen by purified human lung fibroblast collagenase, and structure-activity relationship studies are described. Optimum potency (IC50 values in the nanomolar range) was achieved by incorporating methyl (compounds 43a, 56a, and 57ab) or benzyl esters (44a) at the P1 position. Small amides were also accommodated (e.g. primary amide 47a), but in general, increasing the size of the P1 amide substituent lowered potency. PheNHMe, TrpNHMe, and Tyr(Me)NHMe substituents were found to be approximately equipotent P2'-residues. The results of testing all four diastereoisomers 56a-d of the compound with (S)-TrpNHMe at the P2' position indicated that the S,S,S diastereoisomer 56a possessed highest potency (IC50 2.5 nM) and that the second most potent diastereoisomer was 56d (IC50 12 nM) with the R,R,S configuration. It appeared that the orientation of the P1' and the thiol-bearing centers to each other is a more critical influence on potency than any absolute stereochemical requirements. It is suggested that the high potency of the beta-mercapto carboxylic acid derivatives may be a consequence of bidentate coordination of the thiol and carbonyl groups to the active-site zinc ion in the collagenase enzyme.

Animals↗
PubMed1993

Workshops for consultants on the teaching of clinical communication skills.

A group of senior medical school staff concerned about the short-lived effects of communication training formed the Medical Interview Teaching Association. They felt that communication training needed to be reinforced throughout the curriculum and that this would need active involvement by large numbers of consultants. To achieve this they planned a series of workshops. Seventeen consultants and eight other senior staff agreed to participate in the pilot workshop. This was a 3 1/2-day residential workshop. The structure was adapted from a 'faculty development' model used successfully in the USA. Participants worked mostly in small groups helped by experienced facilitators. The teaching style was learner centred and therefore the details of the problem-based agenda and the choice of working methods were largely determined by the participants themselves. There were also some conventional lectures and demonstrations. Evaluation was by postal questionnaire 2 weeks later. This requested both qualitative comments and Likert scale ratings about every aspect of process and outcome. Most responses were strongly positive. Participants felt they made good progress in developing new skills and new curriculum ideas. They also felt more motivated and self-aware as teachers. The learner-centred approach and the diversity of learning activities were seen as very useful. The unstructured approach to self-awareness training was felt to be less useful. It is concluded that such workshops could well lead to more effective communication training and may also have wider implications for medical education.

Clinical Competence↗
PubMed1993

The facilitation and evocation of seizures. A questionnaire study of awareness and control.

The finding that seizures can be precipitated in some epileptic patients by stimuli which originate from outside the central nervous system is not new. The influence of psychological changes on seizure frequency has, however, been much more difficult to determine. Patients who become aware of such associations may gain some control over their seizures. One hundred randomly selected out-patients with epilepsy were asked about their awareness of such associations and whether, as a consequence, they believed they had any control of their seizures. Ninety-two reported associations between seizures and facilitators or precipitants. The group who had made associations between independent states or stimuli and their seizures were more likely to have poorly controlled seizures and to be taking more anticonvulsants. Many had used this knowledge to control their seizures.

Adaptation, Psychological↗
PubMed1992

Perceptions of psychological problems in general practice: a comparison of general practitioners and psychiatrists.

All general practitioners and psychiatrists working in a single health district were sent a questionnaire on their perceptions of the prevalence of psychological problems among patients consulting in general practice. One hundred and twenty-one GPs (75%) and 10 (83%) psychiatrists responded. GPs and psychiatrists agreed that up to 20% of consulting patients were likely to be clinically depressed; they also agreed on the most appropriate management, although GPs tended to be more conservative than psychiatrists would advise on making use of hospital services. GPs, however, believed non-specific psychological problems to be significantly less common than did psychiatrists. This expectation may help explain the reported failure of GPs to diagnose all psychological problems identified by formal psychiatric instruments.

Adult↗
PubMed1992

The facilitation and evocation of seizures.

Despite the fact that environmental factors have been demonstrated to be important in the genesis of seizures in people with epilepsy, such factors have received scant attention in the education of clinicians or in the provision of services for managing patients with epilepsy. This paper reviews the history of, and literature about, reflex epilepsy, with particular reference to seizures which occur in response to psychological states or stimuli, and discusses the possible implications for management, and the rationale for the use of psychological interventions which may complement drug treatments in the management of epilepsy.

Adolescent↗