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Biomedical subjects

K Thomas

Publications and source records attributed to K Thomas.

At least 37 records · Page 2Linked to original sources
PubMed2003

Classic papers in Urology.

OBJECTIVE: Most clinicians are aware of the importance of using "evidence based medicine" to support their clinical practice, but where does the evidence come from? The aim of this study was to examine the concordance between papers deemed "important" by urologists compared with those selected by the more objective criteria of the citation index. METHOD: To achieve this, two approaches were used; firstly "experts" in various fields of urology were asked to select what they felt were classic papers and secondly urology journals were searched to find the 100 most cited papers for 1982-1997 and 1935-1997. The results of both of these "league tables" were then combined. RESULTS: The most cited papers varied depending on the time period studied. When the experts' selections were combined with those obtained via citation index it was found that the experts had chosen papers with a high citation index from non-urological as well as urological journals. CONCLUSION: It is possible to collate the classic papers within urology and the most effective means of doing so is to combine objective selection with expert choice. This is an exercise that can be repeated within any specialty.

Bibliometrics↗
PubMed2003

A large prostate at radical retropubic prostatectomy does not adversely affect cancer control, continence or potency rates.

OBJECTIVES: To determine the effect of a large prostate at radical retropubic prostatectomy (RRP) on the pathological outcome, biochemical recurrence rates, potency and continence. PATIENTS AND METHODS: From a database of 440 patients treated with RRP, retrospective information was obtained on prostate weights, patient and tumour characteristics, and follow-up. Potency and continence after RRP was obtained using a self-reported validated questionnaire. Patients with prostates of > 75 or < or = 75 g were compared. RESULTS: The median (range) prostate size was 87 (76-182) and 42 (4.1-75) g in the two groups. The response rate to the questionnaire was 78% (344 men). Patients with prostates of > 75 g were older, with a median (range) age of 65 (51-74) years, than the other group, at 61 (40-76) years (P = 0.01), and had higher initial prostate-specific antigen (PSA) levels, at 9.6 (3.4-37.8) and 7.6 (0.1-30.0) ng/mL, respectively (P = 0.001). Tumours within larger prostates were of a lower stage (P = 0.035), lower Gleason grade (median 6 and 7, P = 0.015), of smaller volume (median 1.0, 0.1-12.4; and 1.5, 0.1-21.1 mL; P = 0.04) and more often 'clinically insignificant' (23% and 6%, P = 0.001). There was no difference in the number or distribution of positive surgical margins. For a limited median follow-up of 20-25 months, patients with prostates of > 75 g were less likely to have biochemical recurrence (5% vs 24%, P < 0.001). Potency and continence rates were similar between the groups. CONCLUSIONS: Prostate size at RRP does not affect the risk of impotence or incontinence afterward. A prostate of > 75 g is associated with a lower likelihood of PSA-relapse, potentially as a result of lead-time bias. While an enlarged prostate may contraindicate other potentially curative cancer treatments, the outcomes of RRP appear to be unaffected.

Adult↗
PubMed2003

Aspirin and diabetes: inhibition of amylin aggregation by nonsteroidal anti-inflammatory drugs.

Islet amyloid polypeptide (amylin), cosecreted with insulin by the pancreatic beta-cells, has an important role in the regulation of islet cell hormone homeoastasis. Deposition of beta-sheet polypeptide fibrils into amyloid deposits is considered to be central to the pathology of a number of amyloidogenic disorders, including type-2 diabetes. Amyloid deposits comprised of beta-sheet fibrillar amylin observed in type-2 diabetics are cytotoxic and may have a prominent role in causing beta-cell dysfunction. The amyloidogenic process may impair beta-cell function before cell death and replacement by amyloid. Preservation of beta-cell viability and insulin secretion is a major objective in diabetic care. Using circular dichroism and Congo red absorption techniques we found that clinically relevant doses of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDS) prevented and also reversed the beta-sheet conformation of human amylin. The specific COX-2 inhibitors were less effective. The anti-inflammatory steroid prednisolone or the analgesic acetaminophen had no effect on amylin fibrillogenesis. This action of NSAIDS was similar to their inhibition of beta-sheet conformation of the Alzheimer protein, amyloid-beta. Aspirin, currently recommended for the prevention of cardiovascular complications in diabetic patients, may also ameliorate the disease process in diabetes by preserving the beta-cell function.

Amyloid↗
PubMed2003

Endometrial integrin expression in women undergoing IVF and ICSI: a comparison of the two groups and fertile controls.

BACKGROUND: Integrins are thought to play a vital role in implantation. Three integrins in particular (alpha(4)beta(1), alpha(v)beta(3) and alpha(1)beta(1)) are all present during the implantation window. Defects in their expression have been linked to tubal disease, unexplained infertility and endometriosis. Hence, a reduced endometrial integrin expression would be expected in women attending for IVF due to these causes of infertility when compared with those with male factor infertility attending for ICSI. METHODS: Women attending for IVF (n = 25) and ICSI (n = 25) treatment were recruited, and timed endometrial biopsies were taken during the 'implantation window' (cycle day 20-24). A group of fertile women (n = 15) attending for sterilization was used as controls. RESULTS: There was no significant difference in integrin expression between patients undergoing IVF or ICSI. Neither did these groups differ from the control group. CONCLUSIONS: The endometrium in patients undergoing ICSI treatment is sometimes thought to be more receptive, as the infertility might be due to a male factor. This study shows that there is no significant difference in integrin expression between patients attending for IVF or ICSI and the control group. These data add to the increasing uncertainty about the clinical value of assessing the endometrium with only one marker, in this case integrins.

Adult↗
PubMed2003

Associations between Mycoplasma genitalium, Chlamydia trachomatis and pelvic inflammatory disease.

OBJECTIVE: To evaluate the association between Mycoplasma genitalium, Chlamydia trachomatis, and pelvic inflammatory disease (PID) METHODS: A case-control methodology was used. Swab eluates were processed using the QIAamp DNA mini kit. Polymerase chain reaction (PCR) for M genitalium was carried out using a real time in-house 16S based assay. An endocervical swab was taken and tested for the presence of C trachomatis (ligase chain reaction, Abbott Laboratories), and a high vaginal swab was taken and tested for the presence of Neisseria gonorrhoeae and bacterial vaginosis. RESULTS: Of the PID cases 13% (6/45) had evidence of M genitalium infection compared to none of the controls (0/37); 27% (12/45) of the cases had C trachomatis infection compared to none of the controls; and 16% (7/45) of cases only had serological evidence of C trachomatis infection compared to 5% (2/37) of controls. Cases were more likely to present with M genitalium and/or C trachomatis than controls (p<0.001). CONCLUSIONS: This study indicates that there may be an association between M genitalium and PID, and that this relation is largely independent of C trachomatis. Future studies need to investigate the pathological basis of the relation between M genitalium and PID using samples from women with PID diagnosed using laparoscopy and endometrial biopsy. Little is known about the epidemiology of M genitalium: large scale epidemiological investigations are needed to determine the prevalence, incidence, and factors associated with this emerging infection.

Adult↗
PubMed2003

Associations between Mycoplasma genitalium, Chlamydia trachomatis, and pelvic inflammatory disease.

OBJECTIVE: To evaluate the association between Mycoplasma genitalium, Chlamydia trachomatis, and pelvic inflammatory disease (PID) METHODS: A case-control methodology was used. Swab eluates were processed using the QIAamp DNA mini kit. Polymerase chain reaction (PCR) for M. genitalium was carried out using a real time in-house 16S based assay. An endocervical swab was taken and tested for the presence of C. trachomatis (ligase chain reaction, Abbott Laboratories), and a high vaginal swab was taken and tested for the presence of Neisseria gonorrhoeae and bacterial vaginosis. RESULTS: Of the PID cases 13% (6/45) had evidence of M. genitalium infection compared to none of the controls (0/37); 27% (12/45) of the cases had C. trachomatis infection compared to none of the controls; and 16% (7/45) of cases only had serological evidence of C. trachomatis infection compared to 5% (2/37) of controls. Cases were more likely to present with M. genitalium and/or C trachomatis than controls (p<0.001). CONCLUSIONS: This study indicates that there may be an association between M. genitalium and PID, and that this relation is largely independent of C. trachomatis. Future studies need to investigate the pathological basis of the relation between M. genitalium and PID using samples from women with PID diagnosed using laparoscopy and endometrial biopsy. Little is known about the epidemiology of M. genitalium: large scale epidemiological investigations are needed to determine the prevalence, incidence, and factors associated with this emerging infection.

Adolescent↗
PubMed2003

Drug resistant tuberculosis in diabetes mellitus: a retrospective study from south India.

This study was conducted in a tertiary care teaching hospital in south India to evaluate the association of drug resistant tuberculosis (TB) in diabetic subjects. There were: 361 subjects with positive mycobacterial culture and susceptibility tests results over a 3-year period; 267 (74%) acid-fast bacillus smear positive; and 94 (26%) smear negative cases. One hundred and seventy-seven (49%) had resistant isolates to any one first line antiTB drugs (resistant group) and 184 (51%) had isolates sensitive to all drugs (non-resistant group). In the resistant and non-resistant subjects the mean duration of TB symptoms was, respectively, 22 months and 4.5 months, past history of TB 126 (71%) and 48 (26%), past antiTB drug therapy 126 (71%) and 47 (25%), inadequate anti TB drug therapy 42 (24%) and 23 (13%), HIV positive six and 13 subjects. There were 72 diabetic subjects [35 and 37, respectively] with a duration of diabetes 5.8 +/- 7.5 years and 3.7 +/- 5.0 years in the resistant and non-resistant groups. Twenty-six per cent of the diabetic subjects (19/72) had multi-drug resistantTB. Drug resistance to first line anti-TB drugs was not found to be associated with diagnosis or duration of diabetes mellitus.

Adult↗
PubMed2002

Nasopharyngeal carriage of Haemophilus influenzae.

OBJECTIVE: Nasopharyngeal colonization of Haemophilus influenzae (H. influenzae) in young children may be important in developing countries. METHOD: In this study, we screened school going children for carriage of H. influenzae. A total of 44 H. influenzae isolates out of a collection of 162 were characterized for biotypes, capsular serotypes and antibiotic resistance. RESULTS: A significant proportion of H. influenzae (25/44) isolates were serotype b. High antibiotic resistance was observed against commonly administered antibiotics like ampicillin (79%), chloramphenicol (20%), trimethoprim sulfamethoxazole (84%) and erythromycin (95%). Comparison of antibiotic resistance profile of nasopharyngeal isolates was observed to be correlated with those of H. influenzae from disease. CONCLUSION: Multidrug resistant nasopharyngeal H. influenzae in young healthy children may act as reservoir. Monitoring of antibiotic resistance among nasopharyngeal H. influenzae as a surrogate for invasive H. influenzae seems an attractive option.

Age Distribution↗
PubMed2002

Parental responses to first and recurrent febrile convulsions.

OBJECTIVE: To compare parental knowledge, attitudes, concerns, and first-aid practices for children experiencing febrile convulsions (FC). SUBJECTS AND METHODS: A questionnaire was mailed to 326 FC parents from 11 emergency departments in southern Taiwan. RESULTS: A total of 109 first- and 107 recurrent-FC parents responded 1-3 months after the FC. Most incorrectly believed an electroencephalogram (EEG) or computed tomography (CT) was necessary; immunization should be postponed, and overestimated the risk of subsequent epilepsy. Parents were concerned about further attacks in the night, fever episodes, and frequently measured the child's body temperature. During the first episode, objects were inserted into the child's mouth and they were rushed to a hospital. One third lowered the child's body temperature, and 15% positioned the children on their side. For subsequent seizures, 80% anticipated rushing the child to a hospital, and 44% would put objects into the child's mouth. In comparison, although the recurrent-FC parents had higher scores in knowledge and attitudes than the first-FC parents, low knowledge scores (40% correct) were seen in both groups. No significant differences were found on parental concerns, performed/anticipated first aid for FC. CONCLUSION: Most FC parents had inadequate knowledge, high concerns, and improper first-aid practices. This suggests that parents with either first- or recurrent-FC children need information, emotional support, and first-aid demonstrations.

Adult↗
PubMed2002

The effect of gonadotrophic stimulation on integrin expression in the endometrium.

BACKGROUND: Despite many recent advances in IVF treatment implantation rates per embryo transfer rarely exceed 30%. Three integrins (alpha(1)beta(1),alpha(4)beta(1) and alpha(v)beta(3)) have been shown to be expressed in the endometrium in a cyclically dependent manner and are thought therefore to play a vital role in the process of implantation. METHODS: The effect of gonadotrophin stimulation on the expression of these three integrins within the endometrium was investigated by examining biopsies from oocyte donation patients and comparing them with fertile controls. RESULTS: A delay in the maturation of the glandular epithelium was found in the oocyte donation patients. There was also a reduction in the expression of all three integrins in the glandular epithelium and also a reduced expression of the alpha(v)beta(3) integrin in the luminal epithelium. CONCLUSIONS: As these integrins have been shown to be important in implantation their reduced expression after IVF treatment may have an adverse effect on pregnancy rates.

Adult↗
PubMed2002

Control of the human inhibin alpha chain promoter in cytotrophoblast cells differentiating into syncytium.

Inhibins are dimeric proteins consisting of a common alpha subunit linked to one of the beta subunits, beta A or beta B. During pregnancy, the placenta is the main source of inhibin A production and the in-vitro transformation of cytotrophoblast cells into syncytium is associated with an inhibin alpha subunit mRNA up-regulation. In this study, the 5' region of the human inhibin alpha gene was isolated and sequenced. Three transcription initiation sites were identified. When transiently transfected in trophoblast cells with a luciferase reporter vector, the sequence displayed promoter activity. DNase I footprinting and electrophoretic mobility shift assay (EMSA) analysis showed a specific DNA-protein interaction in the promoter when using cytotrophoblast nuclear proteins. This interaction was weaker with syncytiotrophoblast nuclear proteins. Moreover, the deletion of this DNA-protein interaction region suppressed the promoter activity. In an attempt to identify this factor, the potential binding of known factors delta EF1, AP1 and NFE2 were excluded by competition EMSA experiments. We suggest that it may correspond to an undescribed protein interaction. The identification of the human inhibin alpha promoter could help in understanding the mechanisms modulating inhibin gene transcription. Moreover, the identification of a factor, whose presence is related to the trophoblast cell differentiation state, could help in understanding the transformation of cytotrophoblast cells into syncytium.

Animals↗
PubMed2002

Outcome of the artificial urinary sphincter in female patients.

PURPOSE: We reviewed the outcome in female patients at our unit in whom an artificial urinary sphincter was inserted. MATERIALS AND METHODS: We reviewed notes on 68 patients and mailed a questionnaire to those without recent followup. RESULTS: Median time since insertion was 12 years. Overall 25 patients (37%) had the original artificial urinary sphincter in situ and were dry at a median followup of 7 years. The artificial urinary sphincter was replaced for loss of function in 12 patients, of whom 11 were dry with the replaced device. The device was removed for erosion or infection in 31 patients, of whom 19 underwent successful replacement or were continent after removal. Overall 55 of 68 patients (81%) were continent. Those with neuropathic bladder dysfunction achieved a continence rate of greater than 90%, although half required sphincter removal initially. When the indication for insertion was stress incontinence, 70% of the patients had the original or a replaced artificial urinary sphincter in situ and 82% were continent. All patients with previous pelvic irradiation had the sphincter removed and urinary diversion was done. CONCLUSIONS: The overall continence rate in female patients after insertion of an artificial urinary sphincter is satisfactory. A satisfactory outcome was achieved in terms of stress incontinence and we would recommend an artificial urinary sphincter after an adequate anti-stress incontinence operation fails. Continence in patients with neuropathic bladder dysfunction is excellent and the artificial urinary sphincter should be considered first line treatment in this group, although the risk of revision surgery is high. Pelvic irradiation is a contraindication to the artificial urinary sphincter in female patients.

Adolescent↗
PubMed2002

Epidemiological typing of Streptococcus pneumoniae from various sources in India & Korea using Box A PCR fingerprinting.

BACKGROUND & OBJECTIVES: Epidemiological typing of Streptococcus pneumoniae is necessary to study genetic relatedness among strains. The Box A PCR assay, a good epidemiological tool for high resolution typing of pneumococcal isolates, was used for comparison of strains of S. pneumoniae from Korea, an area of high penicillin resistance and India with low resistance to penicillin. METHODS: The pneumococcal strains from Indian and Korean sources included in the study belonged to serotypes 19F, 23F, 6A & 6B. The penicillin susceptibility of the strains was confirmed by determination of minimum inhibitory concentration values. The strains were then fingerprinted using the Box A PCR protocol and the results were further analysed by Molecular Analyst Software. RESULTS: The Box fingerprinting technique produced sharp, clear and reproducible banding patterns for strains of S. pneumoniae included in the study. There was no similarity between Indian and Korean strains at the genetic level. Among the Korean strains with similar serotypes, the level of similarity varied. Except for one pair (serotype 23F), that showed a level of homology of about 90 per cent, almost all the others showed less than 80 per cent homology. It was also seen that there was a high percentage of homology (> 90% in nasopharyngeal isolates from India belonging to serotype 19F) between isolates from similar source. Comparison of the Indian and Korean isolates of similar serotype showed low homology, except for one cluster of two strains with serotype 6B which showed 84 per cent homology (blood isolates from India and Korea). INTERPRETATION & CONCLUSION: Box A PCR is a highly discriminatory and useful method for typing S. pneumoniae. The results of the study have shown low levels of homology between strains from within India and also between two geographically distinct areas.

Bacterial Typing Techniques↗
PubMed2001

Aspirin and non-steroidal anti-inflammatory drugs inhibit amyloid-beta aggregation.

The neurotoxic and proinflammatory actions of the Alzheimer peptide amyloid-beta (Abeta) are dependent on its aggregation and beta-sheet conformation. Chronic use of non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin for arthritis decreases the risk of developing Alzheimer's disease (AD) by unknown mechanisms. We report that these drugs inhibit human Abeta aggregation in vitro and reverse the beta-sheet conformation of preformed fibrils at clinically relevant doses. Aspirin prevented enhanced Abeta aggregation by aluminum, an environmental risk factor for AD. This anti-aggregatory effect was restricted to NSAIDs and was not exhibited by other drugs used in AD therapy. NSAIDS may have a role in the prevention and treatment of AD, in addition to a number of age-related disorders such as arthritis, cardiovascular disease and cancer.

Alzheimer Disease↗
PubMed2001

Human reserve pluripotent mesenchymal stem cells are present in the connective tissues of skeletal muscle and dermis derived from fetal, adult, and geriatric donors.

This study details the profile of 13 cell surface cluster differentiation markers on human reserve stem cells derived from connective tissues. Stem cells were isolated from the connective tissues of dermis and skeletal muscle derived from fetal, mature, and geriatric humans. An insulin/dexamethasone phenotypic bioassay was used to determine the identity of the stem cells from each population. All populations contained lineage-committed myogenic, adipogenic, chondrogenic, and osteogenic progenitor stem cells as well as lineage-uncommitted pluripotent stem cells capable of forming muscle, adipocytes, cartilage, bone, fibroblasts, and endothelial cells. Flow cytometric analysis of adult stem cell populations revealed positive staining for CD34 and CD90 and negative staining for CD3, CD4, CD8, CD11c, CD33, CD36, CD38, CD45, CD117, Glycophorin-A, and HLA DR-II.

Aged↗
PubMed2001

Clonogenic analysis reveals reserve stem cells in postnatal mammals: I. Pluripotent mesenchymal stem cells.

Clonal populations of lineage-uncommitted pluripotent mesenchymal stem cells have been identified in prenatal avians and rodents. These cells reside in the connective tissue matrices of many organs and tissues. They demonstrate extended capabilities for self-renewal and the ability to differentiate into multiple separate tissues within the mesodermal germ line. This study was designed to determine whether such cells are present in the connective tissues of postnatal mammals. This report describes a cell clone derived by isolation from postnatal rat connective tissues, cryopreservation, extended propagation, and serial dilution clonogenic analysis. In the undifferentiated state, this clone demonstrates a high nuclear-to-cytoplasmic ratio and extended capacity for self-renewal. Subsequent morphological, histochemical, and immunochemical analysis after the induction of differentiation revealed phenotypic markers characteristic of multiple cell types of mesodermal origin, such as skeletal muscle, smooth muscle, fat cells, cartilage, and bone. These results indicate that this clone consists of pluripotent mesenchymal stem cells. This report demonstrates that clonal populations of reserve stem cells are present in mammals after birth. Potential roles for such cells in the maintenance, repair, and regeneration of mesodermal tissues are discussed.

Animals↗