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Biomedical subjects

A Mathews

Publications and source records attributed to A Mathews.

At least 19 recordsLinked to original sources
PubMed2004

Mandibular invasion in oral squamous cell carcinoma: investigation by clinical examination and orthopantomogram.

Assessing the relationship of oral squamous carcinoma with the mandible prior to definitive therapy poses a perplexing problem for the head and neck oncologist. We carried out a prospective open study of 51 (21 female and 30 male; mean age of 53.4 years) patients undergoing mandibular resections for oral squamous cell carcinoma to examine the incidence of mandibular bone invasion and to assess the predictive capabilities of clinical and radiological examination in detecting bone involvement. A detailed clinical examination was followed by radiographic evaluation of mandible for bone invasion. After resection, the mandible was sectioned serially at every cm to find the pathological bone involvement. Sensitivity, specificity, and positive and negative predictive values of clinical and radiological findings were calculated. Specimens from 25 patients (49%) (4 segmental 21 hemi) demonstrated tumour invasion on histological examination. Clinical impression of mandibular invasion showed a sensitivity of 96% and specificity of 65%, whereas radiological examination had a sensitivity of 92% and specificity of 88%. When considered together, clinical and radiological examinations were able to detect all the cases of bone invasion, but specificity was only 58%. This study advocates careful correlation of clinical and radiological findings prior to definitive therapy, as clinical examination tends to over diagnose bone invasion in tumours adjacent to the mandible. The specificity of imaging was also found to be low pointing towards the need for more specific diagnostic tools in doubtful cases. Aggressive surgical therapy, namely segmental or hemi resection of mandible is warranted in case of tumours of the lower alveolus with definite bone invasion. In case of carcinomas of the buccal mucosa and tongue the mandibular resection can be limited to that required for clearance of margins provided the radiology is negative.

Adult↗
PubMed2003

Negative self-imagery blocks inferences.

Previous research has shown that, unlike non-anxious individuals, people with social phobia fail to generate non-threatening inferences when ambiguous social information is first encountered (i.e. 'on-line'; Hirsch and Mathews Journal of Abnormal Psychology, 109 (2000) 705-712). Patients with social phobia also report negative self-imagery in social situations, while individuals without high social anxiety do not. The negative self-imagery in social phobia may prevent the generation of non-threatening inferences. If so, then training non-anxious individuals to hold in mind a negative self-image should remove the 'on-line' non-threat inferential bias normally evident in this population. In the present study, low anxious volunteers were allocated to negative image training or a control task that did not manipulate self-imagery. Following negative image training, or the control task, volunteers read descriptions of job interviews and at certain points during the text performed lexical decisions. Some decisions were made after ambiguous text that could have been interpreted in both a threatening and a non-threatening manner. In a baseline condition, decisions were made following the text for which there was only one possible inference (either threat or non-threat). The results for the control group replicated earlier findings of a non-threat inferential bias for non-anxious individuals. In contrast, and as predicted, non-anxious volunteers who were trained to hold a negative image in mind lacked any non-threatening inferential bias, and also experienced higher levels of state anxiety.

Adult↗
PubMed2002

Carcinosarcoma of the parotid gland with epithelial-myoepithelial carcinoma and pleomorphic sarcoma components.

We report a case of true malignant mixed tumour (carcinosarcoma) of the parotid gland with epithelial-myoepithelial carcinoma and pleomorphic sarcomatous components in a 68-year-old woman. The pleomorphic sarcomatous component behaved aggressively with lymph node and distant metastases. The biological behaviour of the individual components in a malignant mixed tumour makes it difficult to diagnose. We could find no previous report of epithelial-myoepithelial carcinoma as a component of a carcinosarcoma of the parotid.

Aged↗
PubMed2002

Palivizumab is highly effective in suppressing respiratory syncytial virus in an immunosuppressed animal model.

Respiratory syncytial virus (RSV) is widely recognized as a leading cause of pneumonia, with substantial mortality, in bone marrow transplant recipients. We tested the efficacy of a systemic monoclonal antibody (MAB) preparation possessing a high titer of anti-RSV neutralizing antibody, palivizumab (Synagis) for prophylaxis and therapy of RSV infection in cytoxan (CY) immunosuppressed cotton rats, a model in which the efficacy of a polyclonal anti-RSV product (Respigam) has been demonstrated. Both prophylaxis and therapy with this MAB were highly effective in reducing pulmonary viral replication. However, multiple sequential therapeutic doses of MAB were necessary to control rebound viral replication in continually suppressed animals.

Animals↗
PubMed2002

Infrequent loss of heterozygosity of the major tumour suppressor genes in Indian oral cancers.

The loss of heterozygosity (LOH) in tumour suppressor gene loci such as p53, retinoblastoma (rb) and adenomatous polyposis coli (apc) were analyzed in oral cancer tissues with matched controls by employing polymerase chain reaction based/restriction fragment length polymorphism (PCR-RFLP), variable number of tandem repeats (PCR-VNTR) analysis and microsatellite assay. The PCR-RFLP analysis showed an infrequent LOH in rb (17%), p53 (11%) and apc (10%) loci in these cases. The microsatellite assay also revealed only a low frequency of LOH in the microsatellite markers such as TP53 (25%), D5S505 (10%) and D3S1067 (0%) in the same samples. In contrast to the present study, similar studies from Western countries have reported a high frequency of LOH in p53, rb and apc genes in oral cancer tissues. The present preliminary study indicates that the gene aberration by LOH may be an insignificant mechanism in Indian oral cancers with respect to the tumour suppressor genes examined.

Adult↗
PubMed2002

Intramuscular lipomatosis of tongue.

A rare case of intramuscular lipomatosis of the tongue with intramuscular invasion in a 42 year old man is presented. The literature is reviewed and the clinical features, pathology, and treatment are discussed briefly.

Adult↗
PubMed2001

Subunit dissociation and reassociation leads to preferential crystallization of haemoglobin Bart's (gamma4) from solutions of human embryonic haemoglobin Portland (zeta2gamma2) at low pH.

A variety of human haemoglobins (Hbs) are produced at different stages of human development, including three embryonic Hbs, foetal Hb and adult Hb. All are heterotetramers. During crystallization experiments on human embryonic Hb Portland (zeta(2)gamma(2)), it was discovered by crystallographic and biochemical analysis that the homotetramer Hb Bart's (gamma(4)) preferentially crystallizes from zeta(2)gamma(2) solutions below pH 5. This results from dissociation of Hb Portland into gamma(2) dimers and zeta monomers and has interesting implications for subunit interactions and tetramer stability in Hbs. It also makes possible a full crystallographic analysis of Hb Bart's, which is of considerable medical significance because of its presence in the red blood cells of millions of people worldwide who suffer from alpha-thalassaemia.

Chromatography, High Pressure Liquid↗
PubMed2001

Anxiety, depression, and the content of worries.

Worry content as assessed by using a modified Worry Domains Questionnaire (WDQ) was compared among participants diagnosed with a depressive disorder, generalized anxiety disorder (GAD), and both a depressive disorder and GAD. A discriminant function analysis of worry domains yielded two significant functions. The worry domains Lack of Confidence, Aimless Future, Relationships, and Financial Concerns loaded significantly on Function 1, which was termed "Depressive Worries." The worry domain Loss of Control loaded significantly on Function 2, which was termed "Anxious Worries." The three participant groups differed in their pattern of worries in a way that lends support to the content-specificity hypothesis for both depression and anxiety. In addition, multiple regression analysis indicated that WDQ domain scores (in particular the Aimless Future domain) predicted the severity of depressive symptoms even after the variance contributed by anxiety symptoms was removed from the analysis. These findings suggest that the content of a person's worries may be significantly associated with the presence of depression, anxiety, or comorbid depression and anxiety.

Adult↗
PubMed2001

Anxiety and cognitive inhibition.

In 3 experiments, the authors investigated whether anxiety proneness is associated with impaired inhibitory processing. Participants made speeded decisions requiring inhibition of threatening or neutral meanings of ambiguous words, which were inappropriate in their current context. In Experiment 1 there were no differences found in inhibitory processing associated with anxiety. However, in Experiment 2, when the capacity for controlled processing was reduced by imposition of a mental load, anxious individuals showed a response pattern consistent with a general impairment of inhibitory processing. In Experiment 3, a group who had experienced a traumatic event also showed evidence of impaired inhibition, despite the absence of additional load. Thus anxiety proneness is associated with a general deficit of inhibitory processing, but this may be revealed only under conditions that limit the availability of controlled processing resources.

Adult↗
PubMed2001

Anxiety and attention to threatening pictures.

Previous research using attentional search tasks has revealed an anxiety-related bias favouring attention to threatening words when they are presented simultaneously with emotionally neutral words. In Experiment 1, using a similar task, a related effect was found here with emotionally threatening pictures. When pictures were used as location cues in a second experiment, high-trait anxious individuals were slower than less anxious controls when responding to targets requiring attentional disengagement from threat, and they were slower in general with pictures judged to be highly threatening. In a third experiment using the same task but with a longer cue exposure, a related disengagement difficulty occurred across both groups, although the more general slowing with severe threat was again confined to the anxious group. We conclude that attentional bias involves both a specific difficulty in disengaging attention from the location of any threat and a more general interference effect that is related to threat level.

Adolescent↗
PubMed2000

Reduction of anxiety during MR imaging: a controlled trial.

An anxiety reduction protocol was developed and evaluated for routine use with neurology and neuropsychiatry patients undergoing brain or spinal scans. Thirty five patients underwent standard procedures, with limited information given in advance. Twenty nine experimental patients received a booklet giving information about the scanning procedure and advice on cognitive strategies for anxiety reduction, a tape-recorded demonstration of scanner noise, a visit to the control room before entering the scanner, a device to signal for adjustment of music volume, precise timings of each scan, and a clock visible during scanning. Anxiety was measured before, during, and after scanning, using subjective ratings and a retrospective version of the Spielberger State Anxiety Scale. There was no difference in anxiety between groups immediately prior to the scan and immediately after entering the scanner. Patients in the experimental group were significantly less anxious during the scan than control patients, as measured by mean anxiety ratings made during the imaging procedure and by retrospective State Anxiety scores completed immediately after leaving the scanner. The results show that scan-related anxiety can be reduced by introducing these simple changes to MR imaging procedures, with minimal cost, no special training of staff, and no disruption of the running of the MR Unit.

Adult↗
PubMed2000

Impaired positive inferential bias in social phobia.

People with social phobia report anticipatory and retrospective judgments about social situations that appear consistent with a negative interpretative bias. However, it is not at all clear that biased interpretative inferences are made "on-line;" that is, at the time that ambiguous information is first encountered. In a previous study, volunteers who were anxious about interviews were found to lack the positive on-line inferential bias that was characteristic of nonanxious controls but also failed to show a bias favoring threatening inferences (C. R. Hirsch & A. Mathews, 1997). This finding was confirmed in the present study, in which social phobic patients showed no evidence of making on-line emotional inferences, in contrast with socially nonanxious controls who were again clearly biased in favor of positive inferences. The authors concluded that nonanxious individuals are characterized by a benign on-line inferential bias, but that this is impaired in people with social phobia.

Adult↗
PubMed2000

Effects of training on interpretation of emotional ambiguity.

In four experiments we investigated whether interpretative biases found in anxious patients and high-trait anxious individuals can be induced by training in unselected volunteers. Repeated exposure to emotionally valenced (threatening) meanings of homographs during training was followed by relatively faster resolution of word fragments and faster lexical decisions for targets that matched the trained valence. Similar effects were found whether participants generated the meanings themselves, or verified a particular meaning of the homograph. Finally, comparison with a baseline condition confirmed that systematic exposure to threatening--but not non-threatening--resolutions of ambiguous words led to generally faster access times for congruent meanings, thus resembling the interpretative bias seen in anxiety states.

Adult↗
PubMed2000

Induced emotional interpretation bias and anxiety.

Five experiments are reported showing that the interpretation of personally relevant emotional information can be modified by systematic exposure to congruent exemplars. Participants were induced to interpret ambiguous information in a relatively threatening or a benign way. Comparison with a baseline condition suggested that negative and positive induction had similar but opposing effects. Induction of an interpretative bias did not require active generation of personally relevant meanings, but such active processing was necessary before state anxiety changed in parallel with the induced interpretative bias. These findings provide evidence consistent with a causal link between the deployment of interpretative bias and anxiety and reveal something of the processes underlying this association.

Anxiety↗
PubMed1999

Attentional reactions to an MI: the impact of mood state, worry, and coping style.

This study investigated the possible development of an attentional bias to cardiac-related words in subjects who recently experienced a myocardial infarction (MI). It was hypothesized that cardiac-related stimuli would have attention-capturing characteristics for post-MI subjects, and this bias would be moderated by level of anxiety, degree of cardiac-related worry, and the subject's coping style. Post-MI subjects (n = 33) and matched controls (n = 31) participated in an attentional search task. The post-MI subjects failed to show the predicted group increases in attention allocated to cardiac stimuli, but a difference between groups still occurred as the control group exhibited directed inattention to cardiac stimuli. Subsequent analysis indicated those post-MI subjects who did evince an attentional bias toward cardiac stimuli had higher monitoring scores on a self-report measure of coping style. Level of emotional distress and cardiac-related worry failed to predict attentional bias for the post-MI subjects.

Adaptation, Psychological↗
PubMed1999

A strategy for reducing maternal mortality.

A confidential system of enquiry into maternal mortality was introduced in Malaysia in 1991. The methods used and the findings obtained up to 1994 are reported below and an outline is given of the resulting recommendations and actions.

Adolescent↗
PubMed1998

No evidence of infection with porcine endogenous retrovirus in recipients of porcine islet-cell xenografts.

BACKGROUND: The study of whether porcine xenografts can lead to porcine endogenous retrovirus (PERV) infection of recipients is critical for evaluating the safety of pig-to-man xenotransplantation. PERV is carried in the pig germline, and all recipients of porcine tissues or organs will be exposed to the virus. METHODS: We studied 10 diabetic patients who had received porcine fetal islets between 1990 and 1993, looking for evidence of PERV infection by using PCR serology, PCR, and reverse transcriptase assays. Prolonged xenograft survival (up to a year) was confirmed in five patients by porcine C-peptide excretion and detection of pig mitochondrial DNA (mtDNA) in serum. FINDINGS: Despite the evidence for extended exposure to pig cells and despite concomitant immunosuppressive therapy, we were unable to detect markers of PERV infection in any patient. Screening for two PERV sequences in peripheral blood lymphocytes collected 4-7 years after the xenotransplantation was negative. Markers of PERV expression, including viral RNA and reverse transcriptase, were undetectable in sera from both early (day 3 to day 180) and late (4-7 years) time points. Western blot analysis for antibodies was consistently negative. INTERPRETATION: These results suggested the absence of PERV infection in these patients. Also this study establishes a minimum standard for post-transplant surveillance of patients given porcine xenografts.

Adult↗