Search PubMed⌕ Search

Biomedical subjects

S Duffy

Publications and source records attributed to S Duffy.

At least 91 records · Page 5Linked to original sources
PubMed1995

Development of a scoring system to judge the scientific quality of information from case-control and cohort studies of nutrition and disease.

A scoring system was developed to help judge the scientific quality of observational epidemiologic studies linking diet with risk of cancer. The scoring system was developed from key headings used in developing research protocols and included questions under headings: three for case-control studies (dietary assessment, recruitment of subjects, and analysis) and four for cohort studies (dietary assessment, definition of cohort, ascertainment, and analysis). Points were awarded for questions in each section, and a total score was derived. Interobserver variation was assessed for five case-controls and five cohort studies for 13 observers: 1 observer repeated the assessment of each paper. Absolute scores and ranking within observer were assessed. There was good agreement between observers in the ranking of studies. Papers that scored higher presented sufficient detail to enable the questions in the scoring system to be answered more easily. For some studies, the information required was either not collected or, if it was collected, not presented. In either case, the frequent lack of information available to judge papers raises questions about the editorial policy and review process of journals publishing dietary studies as much as it does about the scoring system. Applying the scoring system to a review of meat and cancer risk suggested that, taking the score into account, from what seemed like a large literature, there were relatively few studies that scored well (defined as a score > 65%), but these studies tended to provide more consistent information.

Case-Control Studies↗
PubMed1995

The pathology of hysterectomy specimens following trans-cervical resection of the endometrium.

The pathological findings in 29 hysterectomy specimens from a series of 175 patients undergoing trans-cervical resection of the endometrium are presented. In all but one case endometrium was present. Although all phases of the normal menstrual cycle were represented, in nine (28%) cases the endometrium appeared inactive, sometimes showing appearances similar to those in Asherman's syndrome. Adenomyosis was present in five (17%) cases and simple hyperplasia in one case. Haematocolpos was present in two cases. Inflammation was uncommon, usually mild in degree and present in the superficial myometrium. Four (14%) cases contained epithelioid or foreign body granulomas in the superficial myometrium. Deposits of haemosiderin and amorphous brown and/or particulate black pigment were seen in a total of 20 (69%) cases. A combination of transmission electronmicroscopy and energy dispersive analysis of X-rays showed these pigments to be a combination of charred organic material and metals, the latter corresponding to the composition of the diathermy cutting loop and electrocautery rollerball used in the ablative surgery.

Adult↗
PubMed1995

Monitoring interval cancers in breast screening programmes: the east Anglian experience. Quality Assurance Management Group of the East Anglian Breast Screening Programme.

Interval cancer rates are a major determinant of the success of a screening programme. In the Swedish two county study, on which the United Kingdom programme is based, a 39% reduction in mortality was observed in screened women aged 50-64. Using data from the Swedish study, the relationship between interval cancer incidence and the likely future effect on breast cancer mortality was quantified. In East Anglia, as elsewhere in the United Kingdom, interval cancers rates are nearly double those obtained in Sweden: interval cancer rates in the first, second, and third years respectively, after a negative screen were 24%, 59%, and 79% of the expected underlying incidence in the absence of screening. The corresponding figures from the two county study were 17%, 30%, and 56%. From these it was estimated that the mortality reduction in East Anglia will be 21%, which is lower than the 35% observed in invited women in this age group in the Swedish two county study and the 25% specified in the Health of the Nation target. In a rereading exercise, using screening mammograms from women who were screen normal, who had screen detected cancers, or who subsequently developed interval cancers, four out of five radiologists recommended recall for around 70% of the original mammograms (classed as screen normal at time of screening) from 33 interval cancers. This suggests that sensitivity is a contributory factor to the higher interval cancer rates in East Anglia.

Aged↗
PubMed1995

Follicular fluid levels of midazolam, fentanyl, and alfentanil during transvaginal oocyte retrieval.

OBJECTIVE: To investigate the time course of changes in follicular fluid (FF) concentrations of midazolam (Roche Products Ltd., Welwyn Garden City, United Kingdom), fentanyl (Janssen Pharmaceuticals Ltd., Wantage, United Kingdom), and alfentanil (Janssen Pharmaceuticals Ltd.) during ultrasound-guided transvaginal oocyte collection. STUDY DESIGN: Forty-five patients with tubal infertility were randomized to receive a bolus IV dose of midazolam, fentanyl, or alfentanil for sedation during ultrasound-guided transvaginal oocyte collection. Paracervical block with lignocaine was given for analgesia. Simultaneous blood and FF samples were drawn at 5-minute intervals after the bolus dose for analysis of drug levels. RESULTS: Data were obtained on 15 women receiving midazolam and fentanyl and on 13 women receiving alfentanil. Plasma levels of all agents rose to a peak and then fell in an exponential fashion as was expected. The FF levels of the agents continued to rise significantly to 25 minutes after the bolus dose, although the absolute level was low when compared with the blood level. There were no significant differences in fertilization or pregnancy rates in the three groups, but patient numbers were small. CONCLUSION: We conclude that midazolam, fentanyl, and alfentanil are found in FF after a single IV dose, but further investigation needs to be undertaken to investigate any potential influence on fertilization and implantation rates.

Adult↗
PubMed1995

Adrenergic calcium signaling in astrocyte networks within the hippocampal slice.

Norepinephrine (NE) and glutamate (Glu) initiate intracellular calcium ([Ca2+]i) transients, oscillations, and intracellular [Ca2+]i waves in cultured astrocytes. To further elucidate the significance of NE- and Glu-evoked astrocytic [Ca2+]i signaling to neuron-astrocyte communication in the mature CNS, [Ca2+]i of astrocyte networks within hippocampal slices (P21-42) was measured during bath application of NE and Glu receptor agonists. Astrocytes in stratum radiatum were identified by highly negative membrane potentials (75 +/- 3 mV), absence of action potentials, and dye coupling following intracellular injection of the [Ca2+]-sensitive dye calcium orange. NE (2-100 microM) evoked [Ca2+]i increases (7 of 8 slices, 24 of 24 cells in responding slices) characterized by an initial rise, 20-50 sec to peak, followed by a slower return to baseline (over approximately 8 min). The alpha 1-agonist phenylephrine (PE) (10-100 microM) evoked complex [Ca2+]i signals (22 of 26 slices, 90 of 90 cells in responding slices) composed of both a prolonged component (5.1 +/- 1.8 min), synchronized in neighboring cells, and multiple, mainly asynchronous [Ca2+]i spikes (25.0 +/- 11.6 sec). PE responses were completely blocked by the alpha 1-antagonist prazosin (200 nM, n = 4 slices), but not by the alpha 2-antagonist yohimbine (n = 3 slices). The alpha 2-agonist clonidine (10-100 microM) did not increase [Ca2+]i (n = 4 slices). alpha 1-mediated [Ca2+]i transients were observed after removal of extracellular [Ca2+]o (n = 8 of 9 slices), indicating PE-induced Ca2+ release from intracellular stores. Adrenergic responses were mediated by alpha 1-receptors localized to astrocytes because PE and NE increased [Ca2+]i of acutely isolated hippocampal astrocytes. Glu (0.75-2.0 mM) did not increase astrocytic [Ca2+]i in slices (0 of 7), even in the presence of the Glu uptake inhibitor L-trans-pyrrollidine-2,4-dicarboxylic acid (PDC) (0 of 5 slices), or in acutely isolated astrocytes (0 of 7 cells). The metabotropic agonist t-ACPD (30 or 50 microM) did not increase astrocytic [Ca2+]i in hippocampal slices (0 of 5), while kainate (200 microM or 1 mM) induced brief (1-2 min) [Ca2+]i increases only rarely (2 of 8 applications in 6 slices). These results support a primary role of NE release and alpha 1-adrenoceptor stimulation in neuron-astrocyte communication in the mature CNS.

Animals↗
PubMed1995

GABAA/benzodiazepine receptors in acutely isolated hippocampal astrocytes.

The properties of GABA receptor-mediated responses were examined in noncultured astrocytes, acutely isolated from the mature rat hippocampus. Whole-cell patch clamping revealed a GABA-activated Cl- conductance that was mimicked by the GABAA receptor agonist muscimol and depressed by the GABAA antagonists bicuculline and picrotoxin. The GABAA-activated currents were potentiated by the barbiturate pentobarbital and the benzodiazepine diazepam. The benzodiazepine inverse agonist DMCM either enhanced or depressed the astrocytic GABAA-mediated responses, suggesting receptor heterogeneity with respect to pharmacologic profiles. In addition, GABA evoked an increase in [Ca2+]n measured by indo-1 fluorometry, which was depressed in the presence of verapamil or picrotoxin. A GABAA-induced depolarization, therefore, causes Ca2+ influx through voltage-gated Ca2+ channels. The expression and subcellular localization of GABAA receptors and its subunits were examined using immunohistochemical and fluorescent benzodiazepine binding techniques. Polyclonal antisera raised against the GABAA/benzodiazepine receptor, which recognizes multiple subunit isoforms, labeled receptors on the astrocytic cell body and most large processes. In contrast, antisera generated against either alpha 1 or beta 1 subunit peptides revealed immunoreactivity predominantly on a subset of processes. To determine the subcellular distribution of membrane-bound receptors, a fluorescent benzodiazepine derivative was superfused over live astrocytes and visualized with laser-scanning confocal microscopy. Specific fluorescence was distributed in discrete clusters on the cell soma and a subset of distal processes. Collectively, these data support the view that astrocytes, like neurons, express GABAA receptors and target subunit isoforms to distinct cellular localizations. Astrocytic GABAA receptors may be involved in both [Cl-]o and [pH]o homeostasis, and a GABA-evoked increase in [Ca2+]i could serve as a signal between GABAergic neurons and astrocytes.

Amino Acid Sequence↗
PubMed1994

Prevalence of anal human papillomavirus infection and intraepithelial neoplasia in renal allograft recipients.

A study was performed to test the hypothesis that renal allograft recipients are at high risk of developing anal human papillomavirus (HPV) infection and anal intraepithelial neoplasia (AIN). A total of 133 renal allograft recipients and 145 control patients underwent anoscopy and biopsy. A polymerase chain reaction was used to detect HPV16 DNA in biopsy samples. A histological diagnosis of anal HPV infection or AIN was made in 32 allograft recipients (HPV infection, five; AIN I, 20; AIN II, three; AIN III, three; AIN III and anal cancer, one). One subject with AIN was detected in the control group. HPV16 DNA was detected in 47 and 12.4 per cent of anal biopsies in the allograft and control groups respectively. Renal allograft recipients are at high risk of developing anal HPV infection and neoplasia (P < 0.05). Further studies are required to determine whether screening anal examination is required in organ allograft recipients.

Adult↗
PubMed1994

Potassium-dependent calcium influx in acutely isolated hippocampal astrocytes.

Potassium depolarization can increase the intracellular ionized calcium concentration ([Ca2+]i) of cultured astrocytes, but it is not known if astrocytes that have matured in the intact CNS also exhibit voltage-dependent [Ca2+]i signalling. To address this issue, fluorometric measurements of [Ca2+]i were obtained from astrocytes acutely isolated from young adult rat hippocampus. In control artificial cerebrospinal fluid containing 5 mM [K+]o, average resting [Ca2+]i was 195 nM. Elevation of [K+]o to 50 mM caused [Ca2+]i to increase 150 nM to 1 microM above resting levels. The threshold [K+]o necessary to evoke an elevation in [Ca2+]i was 20-25 mM, and the magnitude of the [Ca2+]i signal grew progressively with increasing [K+]o (up to 50 mM). These [Ca2+]i increases were blocked completely by removal of external Ca2+, and markedly suppressed by the calcium channel blockers verapamil (30 microM and greater) and Co2+ (1 mM). Neither reversal of Na(+)-Ca2+ exchange, nor Ca(2+)-activated Ca2+ release, nor Ca2+ influx through stretch-activated channels contributed to the [Ca2+]i increase. These results suggest that [K+]o-evoked [Ca2+]i signals are mediated by influx through voltage-gated calcium channels. In contrast to results from cultured astrocytes and acutely isolated neurons, these [Ca2+]i increases were insensitive to dihydropyridine compounds. We conclude that increases in interstitial [K+], observed in situ during several pathological conditions, trigger voltage-dependent [Ca2+]i signals in astroglial cells. This may constitute an important form of neuron-to-glial communication.

Animals↗
PubMed1994

Detection of fertilization in embryos with accelerated cleavage by fluorescent in-situ hybridization (FISH).

Embryos from a couple undergoing routine in-vitro fertilization for unexplained infertility had shown cleavage by day 1 in two consecutive cycles. The response of the woman to fertility drugs had been normal, and there were no known sperm abnormalities. In a subsequent cycle, accelerated cleavage occurred again and we used a modified method of spreading whole embryos and dual fluorescent in-situ hybridization (FISH) with directly labelled probes for chromosomes X and Y to determine if fertilization had occurred in these embryos. Nine oocytes were collected, five of which had cleaved when examined for pronuclei early on day 1 following late insemination. Pronuclei were observed in one of the remaining oocytes, but in this case, three were present. On day 2, all of the oocytes/embryos had cleaved and two were transferred to the patient. The remaining seven were spread for FISH analysis but nuclei were only obtained from five. In three, a Y signal was detected, indicating that fertilization had occurred. In all five embryos, a wide range of X chromosome signals were observed. These data suggest that the embryos had undergone abnormal fertilization and accelerated cleavage.

Adult↗
PubMed1992

Fee crisis.

Explore the source record for details and available documents.

Denture, Complete↗
PubMed1992

Immunoglobulin V gene expression in CD5 B-cell malignancies.

Chronic lymphocytic leukemia (CLL) and small lymphocytic lymphomas (SLL) generally are malignancies of CD5 B cells. Immunophenotypic and clinicopathologic data, however, are required to distinguish subtypes that apparently have a different cytogenesis than that of conventional CLL or SLL. In addition to expressing CD5, neoplastic cells of the latter are also distinctive in that they frequently coexpress surface immunoglobulin (Ig), bearing one or more cross-reactive idiotypes (CRIs) (e.g. 17.109, G6,) that commonly are found on monoclonal IgM autoantibodies. The frequent occurrence of such CRIs reflects both the biased rearrangement and subsequent selected expression of Ig V genes with little or no somatic mutation. IgM/L CLL, for example, frequently (8/33) harbor abortive Ig rearrangements involving Humkv325, the VK gene encoding the 17.109-CRI. Also, the VH1 gene(s) encoding the G6 CRI accounts for over 10% of all VH genes and over 60% of all the VH1 genes used in randomly selected common CLL/SLL. Furthermore, comparison with the Ig expressed by nonmalignant G6 CRI+ B cells reveals an apparent restriction in the CDR3 of IgH expressed by G6 CRI+ CLL. Coupled with the observed potential bias in antibody light chain and heavy chain pairing in B-CLL, these data suggest that the autoantibodies expressed in this disease are selected based on antigen-binding activity. Collectively, our studies indicate that nonstochastic Ig V gene rearrangement and subsequent selection may influence the Ig repertoire expressed in this common B-cell malignancy.

Animals↗
PubMed1992

Personal touch.

Explore the source record for details and available documents.

Community Health Services↗
PubMed1992

Mutual accord.

Explore the source record for details and available documents.

Contract Services↗
PubMed1992

Preliminary observations of holmium:YAG laser tissue interaction using human uterus.

Preliminary observations of a pulsed Ho:YAG laser on human uterine tissue in-vitro are presented. The tissue effect on the uterine myometrium was demonstrated using fresh uteri which had been subjected to laser energy. The laser crater and surrounding zone of thermal necrosis (ZTN) was quantified. Measurements demonstrated a consistent narrow ZTN (0.8-1.8 mm) irrespective of power or pulse frequency used. The percentage forward transmission of laser energy through 1 mm of myometrium was investigated using a pyroelectric detector and found to be 0.41%. Finally, a visible and measureable photoacoustic component to the Ho:YAG laser was demonstrated using a water bath and needle hydrophone.

Biophysical Phenomena↗
PubMed1992

Preliminary evaluation of a new high power diode laser.

A high-powered semiconductor diode laser (805 nm) has recently been developed for medical use. The laser-tissue interactions of this wavelength have been compared with Nd:YAG (1064 nm). When used in the contact mode, the extent of tissue vaporization and zones of thermal necrosis produced by these two lasers were similar. The diode laser was also an effective and haemostatic laser scalpel. This compact laser unit has potential advantages over existing Nd:YAG lasers.

Animals↗
PubMed1992

Diet and colorectal cancer: results of two case-control studies in Russia.

Two case-control studies of diet and colorectal cancer were conducted in Moscow and Khabarovsk. The Moscow study comprised 100 cases of colorectal cancer and 100 neighbourhood controls. The Khabarovsk study consisted of 117 cases of colorectal cancer and 117 population controls. A history of the usual dietary intake one year prior to interview was taken using a food frequency questionnaire. Effects were adjusted in analysis for energy intake and education. Significantly reduced risks were observed with high intakes of cellulose (P = 0.001), beta-carotene (P = 0.002), vitamin C (P = 0.007), polyunsaturated fatty acids (PUFA) (P = 0.004), cholesterol (P = 0.04), and with a high ratio of PUFA to saturated fatty acids (SFA) (P = 0.002). Significant increases in risk were observed in association with high ratios of intakes of protein to cellulose (P = 0.002) and of fat to cellulose (P = 0.008). High intake of total fat was associated with non-significant decrease in the risk (P = 0.12), while high intake of SFA resulted in statistically non-significant increase in risk (P = 0.40). Significant reductions in risk were associated with high frequencies of consumption of vegetables (P = 0.001) and fruit (P = 0.009). There were results suggestive of a decreased risk with a high frequency of milk consumption (P = 0.06) and an increased risk in association with a ratio of meat to vegetable frequencies (P = 0.09). After adjustment among factors effecting risk of colorectal cancer statistically significant increase in the risk was seen only for protein/cellulose ratio and significant protective effect for PUFA/SFA ratio, beta-carotene and vegetable consumption.

Carotenoids↗
PubMed1992

In-vivo studies of uterine electrosurgery.

OBJECTIVE: To study the effects of electrosurgery on the living human uterus. DESIGN: Prospective observational study. SUBJECTS: Nine women with recurrent refractory dysfunctional uterine bleeding, listed for hysterectomy. INTERVENTION: Experimental endometrial resection on patients immediately prior to hysterectomy. MAIN OUTCOME MEASURES: The influence of power output, duration of exposure and repetition of consecutive surgical applications on the size of the zone of thermal necrosis in uterine tissue. RESULTS: Resection of the endometrium was associated with a narrow zone of thermal necrosis of between 0.69 and 0.76 mm which was not dependent on power output. Duration of exposure, however, was directly related to tissue necrosis (1.44 vs 1.88 mm for 1s and 5s, respectively). Coagulation by pin-point desiccation caused a zone of thermal necrosis of 3.30-3.77 mm that was independent of either power or duration of exposure to electrical energy. Thermal transmission through the uterus in situ, during electrosurgery was minimal, the maximum recorded rise in temperature from the baseline was 0.4 degrees C. The differences between the in vitro and in vivo effects of electrosurgery are highlighted and the possible reasons for these differences explored. CONCLUSIONS: The potential for unwanted thermally-induced damage to the uterus is small.

Electrosurgery↗