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Biomedical subjects

G Thomas

Publications and source records attributed to G Thomas.

At least 55 records · Page 3Linked to original sources
PubMed2003

Pregnancy and lymphangioleiomyomatosis: anaesthetic management.

Lymphangioleiomyomatosis is a rare, progressive cystic pulmonary disease related to tuberous sclerosis complex, affecting almost exclusively females of childbearing age. Progression of the disease is variable but may lead to terminal respiratory failure. As the disease may be oestrogen-dependent, it can arise de novo in pregnancy or established disease may undergo exacerbation. We report on the successful labour and delivery of such a patient and present the results of an internet survey of 30 pregnancies in 15 patients worldwide with lymphangioleiomyomatosis conducted by our patient before delivery.

Journal Article↗
PubMed2003

Socioeconomic status, lifestyle factors and oral premalignant lesions.

Several studies have suggested that low socioeconomic status (SES) is associated with a higher risk of oral cancer, but the association with oral premalignant lesions has not yet been explored. The aim of this study was to examine the association of education, occupation, income and SES index with oral premalignant lesions. A case-control study was conducted with data from the baseline screening of a randomized oral cancer screening trial in Kerala, India. There were a total of 927 oral leukoplakia, 170 oral submucous fibrosis, 100 erythroplakia and 115 multiple oral premalignant lesion cases and 47,773 controls. Subjects with high SES index had protective ORs for oral premalignant lesions, ranging from 0.6 to 0.7, after adjustment for age, sex, BMI, tobacco chewing, smoking, drinking and fruit/vegetable intake. Higher education levels were also associated with decreased risk of all four oral premalignant lesions. Protective ORs for income were observed for oral leukoplakia and possibly oral submucous fibrosis and erythroplakia. SES may be associated with oral premalignant lesions because of access to medical care, health related behaviors, living environment or psychosocial factors. Though the mechanism for the association is not clear, higher SES index, education and income were associated with decreased risk of oral premalignant lesions in our study.

Adult↗
PubMed2003

The effectiveness of screening for diabetic retinopathy by digital imaging photography and technician ophthalmoscopy.

AIMS: To evaluate the introduction of a community-based non-mydriatic and mydriatic digital photographic screening programme by measuring the sensitivity and specificity compared with a reference standard and assessing the added value of technician direct ophthalmoscopy. METHODS: Study patients had one-field, non-mydriatic, 45 degrees digital imaging photography prior to mydriatic two-field digital imaging photography followed by technician ophthalmoscopy. Of these patients, 1549 were then examined by an experienced ophthalmologist using slit lamp biomicroscopy as a reference standard. The setting was general practices in Gloucestershire. Patients were selected by randomizing groups of patients (from within individual general practices) and 3611 patients were included in the study. Patients for reference standard examination were recruited from groups of patients on days when the ophthalmologist was able to attend. The main outcome measure was detection of referable diabetic retinopathy (DR) as defined by the Gloucestershire adaptation of the European Working Party guidelines. RESULTS: For mydriatic digital photography, the sensitivity was 87.8%, specificity was 86.1% and technical failure rate was 3.7%. Technician ophthalmoscopy did not alter these figures. For non-mydriatic photography, the sensitivity was 86.0%, specificity was 76.7% and technical failure rate was 19.7%. CONCLUSIONS: Two-field mydriatic digital photography is an effective method of screening for referable diabetic retinopathy. Non-mydriatic digital photography has an unacceptable technical failure rate and low specificity.

Adolescent↗
PubMed2003

Soft tissue sarcoma of the head and neck region in adults.

Soft tissue sarcomas (STS) are rare solid tumours accounting for less than 1% of all malignancies and are very unusual in the head and neck region. Histopathologically diagnosed cases of STS treated at Regional Cancer Centre (RCC). Trivandrum, India, between January 1989 and November 2000 were analyzed retrospectively. Survival analysis was carried out by Kaplan-Meier method and curves were compared using log rank test. A total of 22 cases were seen during the study period. The mean age of the patients was 36.4 years with male-to-female ratio of 2:1. The neck, lower jaw, tongue, cheek, scalp and maxilla were the commonest sites affected. None of the patients had palpable neck nodes or distant metastasis at presentation. All the patients were treated with primary surgical resection and this was followed by adjuvant treatment in 14 cases (63.6%). After a median follow-up of 14.5 months, two patients died, six developed local recurrence, four developed metastatic disease and another patient developed second primary sarcoma. The overall 5-year survival was 80% while the 5-year disease-free survival rate was 24.1%. The majority of the patients failed within first and second year. None of the parameters except grade of tumour (P=0.008) were found to have a significant effect on survival. The overall survival rate for patients with soft tissue sarcoma of the head and neck is good, however, disease-free survival is poor as the majority of these fail within 2 years of completing treatment.

Adolescent↗
PubMed2003

Ectopic lingual thyroid: a case report.

A rare case of lingual thyroid of massive size is being reported in a 28-year-old female patient who presented with dysphonia, fullness in the throat, dysphagia and breathing difficulties. Fibre-optic nasopharyngoscopy revealed a sessile mass occupying the whole of the oro and hypopharynx. The mass was excised and histopathological examination was reported as thyroid tissue. Postoperatively the patient remained euthyroid and did not require thyroxine supplements since the hypoplastic thyroid gland in the prelaryngeal region remained functional.

Adult↗
PubMed2003

A study of GafChromic XR Type R film response with reflective-type densitometers and economical flatbed scanners.

The GafChromic XR Type R film is a relatively new product for recording high radiation dose in interventional radiological procedures. Means of measuring the film response were studied in this investigation. Two handheld reflective-type densitometers of different models were compared in the range of 0-8 Gy. They were found to be in excellent agreement. Five reflective flatbed scanners of different models were compared by a simple preliminary test. Their widely differed performances suggest the need of testing a scanner before using it for dosimetry measurement. A selected scanner was further tested for its ability to measure radiation in the range of 0-8 Gy and for the development of a scanning protocol. This experiment suggested the inclusion of a calibration pattern with known exposures and a black reference step in the scanning of a film in RGB mode. Then the red component of this image should be used for dosimetry computation. This method was compared to the use of a red acetate filter. The latter was demonstrated to be a possible alternative for measurement below 5 Gy and when there is no software ability to split an image into color components.

Absorptiometry, Photon↗
PubMed2003

CARD4/NOD1 is not involved in inflammatory bowel disease.

BACKGROUND AND AIMS: Inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), are complex genetic disorders. CARD15/NOD2, a member of the Ced4 superfamily which includes Apaf-1 and CARD4/NOD1, has recently been associated with genetic predisposition to CD but additional genetic factors remain to be identified. Because CARD4/NOD1 shares many structural and functional similarities with CARD15, we tested its putative role in IBD. PATIENTS AND METHODS: The 11 exons of CARD4 were screened for the presence of variants in 63 unrelated IBD patients. The only non-private genetic variation encoding for a substitution in the peptidic chain was genotyped in 381 IBD families (235 CD, 58 UC, 81 mixed, and seven indeterminate colitis families) using a polymerase chain reaction-restriction fragment length polymorphism procedure. Genotyping data were analysed by the transmission disequilibrium test. RESULTS: Five of nine sequence variations identified in the coding sequence of the gene encoded for non-conservative changes (E266K, D372N, R705Q, T787M, and T787K). Four were present in only one family. The remaining variant (E266K), which exhibited an allele frequency of 0.28, was not associated with CD, UC, or IBD. Furthermore, IBD patients carrying sequence variations in their CARD4 gene had a similar phenotype to those with a normal sequence. CONCLUSION: Our results suggest that CARD4 does not play a major role in genetic susceptibility to IBD.

Adaptor Proteins, Signal Transducing↗
PubMed2003

Irruption of genomics in the search for disease related genes.

Genomics was initiated when robotics made possible the characterisation of large numbers of DNA fragments and when ever improving computers with dedicated software were applied to the localisation in the genome of these sequences and to the analysis of their content. By enabling the generation and management of large amounts of DNA based sequences these tools have changed our perception of the genomes of living organisms. These data, as applied to humans, are contributing to the understanding of gene function, disease processes, and evolution of our species. Presently they are changing the research strategies for identifying genetic variations influencing disease susceptibility and response to treatment. These advances will have a profound impact in biomedicine.

Chromosome Mapping↗
PubMed2003

Completion of the audit cycle: standardised nurse-led information for patients.

BACKGROUND: It is increasingly accepted that patients want information about their proposed treatment, and that provision of such information may alleviate fear and may improve the process of obtaining informed consent. It is not yet clear what form such information should take. OBJECTIVE: Based on differences shown previously between patients receiving standard treatment and those in clinical trials, a system of routine appointments with a chemotherapy nurse at least one day before the patient offered consent to treatment was established for all patients receiving chemotherapy in Leicestershire, at which time patients were given standardised written information regarding outpatient chemotherapy and specific drugs. METHOD: In order to complete the audit cycle, the previous questionnaire study was repeated. RESULTS: From 160 questionnaires distributed, 131 complete replies were received. Compared with the previous audit, a significantly higher proportion of patients receiving standard chemotherapy remembered being given written information about chemotherapy from a nurse before starting their treatment and remembered signing a consent form. The significant difference in feelings of involvement in the decision to have chemotherapy between patients receiving standard chemotherapy and those in clinical trials detected in the previous audit was no longer detectable, suggesting the clinical effectiveness of the intervention performed. CONCLUSION: Implementation of nurse-led appointments with provision of standardised information before formal consent being taken should be studied further for its potential to improve patients' involvement in medical decision making.

Clinical Trials as Topic↗
PubMed2002

Physical and magnetic modification of co/pt multilayers by ion irradiation.

The microstructure of Co/Pt multilayers with large perpendicular magnetic anisotropy (PMA) was investigated before and after energetic ion irradiation. No pronounced microstructural changes were detected at ion doses sufficient to completely reduce the PMA and cause a spin reorientation transition to in-plane. Ion-induced displacement of Co and Pt atoms near Co/Pt interfaces lead to local "roughening" and Co layer strain relaxation, reducing the PMA. The magnetic domain confinement induced by ion irradiation and magnetic patterning by selective ion irradiation were also investigated.

Alloys↗
PubMed2002

Concurrent cisplatin-based chemotherapy plus radiotherapy for cervical cancer--a meta-analysis.

PURPOSE: To evaluate the role of concurrent cisplatin plus radiotherapy in the treatment of cervical cancer. METHODS: A systematic review of randomized trials of cisplatin administered concurrently with external beam radiotherapy versus radiotherapy without cisplatin for cervical cancer was combined with a meta-analysis of results abstracted from published reports of the trials. RESULTS: Pooled survival rates from eight randomized trials that evaluated the role of cisplatin, alone or in combination with other chemotherapy agents, administered concurrently with external beam radiotherapy to patients with cervical cancer demonstrated a statistically significant effect in favour of cisplatin-based chemotherapy plus radiotherapy compared with radiotherapy without cisplatin (relative risk [RR] of death, 0.74; 95% confidence interval [CI], 0.64 to 0.86). The pooled RR of death among the six trials that enrolled only women with locally advanced cervical cancer was 0.78 (95% CI, 0.67 to 0.90). The pooled relative risk for the two trials in high-risk early-stage disease also demonstrated a statistically significant benefit for the addition of cisplatin-based chemotherapy to radiotherapy (RR=0.56; 95% CI, 0.41 to 0.77). CONCLUSION: This meta-analysis confirms that treatment with concurrent cisplatin-based chemotherapy plus radiotherapy improves overall survival over various controls in women with locally advanced cervical cancer, large stage IB tumours (prior to surgery) and high-risk early-stage disease (following surgery). The variation in control treatments and the quality of their delivery among the randomized trials makes interpretation difficult. Nonetheless, the meta-analysis supports the use of concurrent cisplatin with radical radiotherapy in the treatment of cervical cancer.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2002

Parapharyngeal metastasis from papillary microcarcinoma of thyroid: report of a case diagnosed by peroral fine needle aspiration.

A parapharyngeal metastasis from primary thyroid carcinoma is rare and a search of relevant publications disclosed only seven previous reported cases. We describe a 46-year-old man who presented with a left parapharyngeal mass that was subsequently diagnosed by peroral fine-needle aspiration as a metastasis originating from a papillary carcinoma of the thyroid gland. Metastatic thyroid cancer should be considered in the differential diagnosis of a parapharyngeal mass. Fine-needle aspiration cytology is a simple, speedy, and cost-effective method of diagnosis of parapharyngeal masses.

Biopsy, Needle↗
PubMed2002

Minimal early mortality in CABG--simply a question of surgical quality?

BACKGROUND: The increasing number of risk scores and models for the evaluation of the early risk after cardiac surgery reflects the interest in 'calculating' the risk of adverse events. Different time intervals, but also different 'types' of death are generally accepted in the evaluation of early mortality. The aim of this study was to focus on the differences in the calculation of early mortality and to focus on their potentially misleading impact on risk stratification. METHODS: We investigated 7,436 patients who underwent coronary artery bypass grafting from June 30, 1988 through June 30, 2001. A follow-up was performed 180 days after operation (98.7 % complete). RESULTS: According to the definition of 30-day mortality to represent the total time interval between an intervention and the 30th postoperative day, the 30-day mortality was 5.92 % (n = 440 patients). Hospital mortality reflects the number of deaths from the day of intervention through the patient's individual discharge, independent of any fixed time interval. Hospital mortality was 5.86 % (n = 436 patients) in our patient group. 30-day hospital mortality requires the investigation of hospital mortality until the 30th postoperative day; in-hospital and general mortality after the 30th postoperative day remained excluded from the analysis; 30-day hospital mortality was 5.19 % (n = 386 patients). Assuming a maximum hospital stay of 5 days, hospital mortality would decrease to 2.64 % (n = 196 patients). CONCLUSIONS: 30-day mortality, hospital mortality and 30-day hospital mortality are used to determine early outcome. The present data indicate the vulnerability of non-standardized time intervals to discharge policy. However, both hospital mortality and 30-day hospital mortality are predominantly used in current risk scores and models. In view of the comparability and meaning of data, the methodology for the evaluation of early risk should be reconsidered.

Coronary Artery Bypass↗
PubMed2002

The effects of antimalarial drugs on ventricular repolarization.

Cardiotoxicity has become a major concern during treatment with antimalarial drugs. Lengthening of the QTc and severe cardiac arrhythmia have been observed, particularly after treatment with halofantrine for chloroquine-resistant Plasmodium falciparum malaria. The purpose of this prospective study was to evaluate whether antimalarial agents alter dispersion of the QTc and ventricular repolarization dynamicity. Sixty patients with uncomplicated falciparum malaria were randomly allocated in four groups of 15 patients and treated with quinine, mefloquine, artemether, or halofantrine at recommended doses. Patients in treatment groups were compared with a group including 15 healthy controls with no history of malaria and/or febrile illness within the last month. QTc dispersion was measured on surface electrocardiograms. Repolarization dynamicity was analyzed from Holter recordings, which allow automatic beat-to-beat measurement of QT and RR intervals. Plasma drug concentration was determined by reversed-phase high-performance liquid chromatography. No change in QTc dispersion was observed after treatment with quinine, mefloquine, or artemether. Treatment with halofantrine was followed by a significant increase in QTc dispersion at 9 hours (P < 0.0001) and 24 hours (P < 0.01). Assessment of QT heart rate variability by QT/RR nychtohemeral regression slope demonstrated no significant difference between the artemether (mean +/- SEM = 0.170 +/- 0.048), mefloquine (0.145 +/- 0.044), and the control groups (0.172 +/- 0.039). A significant decrease in the Q-eT/RR slope was observed in the quinine group compared with the control and artemether groups (0.135 +/- 0.057; P < 0.04). With halofantrine, a significant increase in the QT/RR regression slope (0.289 +/- 0.118) was observed (P < 0.0002). QTc interval, QT dispersion, and QT regression slope were significantly correlated with halofantrine and quinine plasma concentration. Mefloquine and artemether did not alter ventricular repolarization. Quinine induced a significant decrease in QT/RR slope of the same order of magnitude as those previously observed with quinidine. Both QTc dispersion and QT/RR slope were significantly modified by halofantrine. These repolarization changes were related to a class-III antiarrhythmic drug effect and may explain the occurrence of ventricular arrhythmia and/or sudden deaths reported after halofantrine intake.

Adult↗
PubMed2002

[Stability of the Euro-score as an identification tool for patient risk groups -- dependency of the applied documentation system].

From the different methods for risk adjustment, scores allow a rough classification of the patients. The Euroscore represents one of the most modern scores. The most recent version of the documentation system of the German Society for Thoracic and Cardiovascular Surgery may be used without extended extra-work to evaluate the Euroscore despite the presence of various limitations. The investigation of the scores with nearly complete adaptation of the variables of the quality assurance documentation to the original definition showed no substantial differences between the score groups. However, many methodological implications favor the development of self-evaluated models to obtain a most recent weight for each risk factor and to be able to take into account new therapeutical options. These models can be evaluated by the existing database and extended by the most recent data.

Cardiac Surgical Procedures↗
PubMed2001

PDK1 regulates growth through Akt and S6K in Drosophila.

The insulin/insulin-like growth factor-1 signaling pathway promotes growth in invertebrates and vertebrates by increasing the levels of phosphatidylinositol 3,4,5-triphosphate through the activation of p110 phosphatidylinositol 3-kinase. Two key effectors of this pathway are the phosphoinositide-dependent protein kinase 1 (PDK1) and Akt/PKB. Although genetic analysis in Caenorhabditis elegans has implicated Akt as the only relevant PDK1 substrate, cell culture studies have suggested that PDK1 has additional targets. Here we show that, in Drosophila, dPDK1 controls cellular and organism growth by activating dAkt and S6 kinase, dS6K. Furthermore, dPDK1 genetically interacts with dRSK but not with dPKN, encoding two substrates of PDK1 in vitro. Thus, the results suggest that dPDK1 is required for dRSK but not dPKN activation and that it regulates insulin-mediated growth through two main effector branches, dAkt and dS6K.

3-Phosphoinositide-Dependent Protein Kinases↗
PubMed2001

Mammalian TOR: a homeostatic ATP sensor.

The bacterial macrolide rapamycin is an efficacious anticancer agent against solid tumors. In a hypoxic environment, the increase in mass of solid tumors is dependent on the recruitment of mitogens and nutrients. When nutrient concentrations change, particularly those of essential amino acids, the mammalian Target of Rapamycin (mTOR) functions in regulatory pathways that control ribosome biogenesis and cell growth. In bacteria, ribosome biogenesis is independently regulated by amino acids and adenosine triphosphate (ATP). Here we demonstrate that the mTOR pathway is influenced by the intracellular concentration of ATP, independent of the abundance of amino acids, and that mTOR itself is an ATP sensor.

Adaptor Proteins, Signal Transducing↗