Social signalling in the domestic fowl: role of UV(A) light in mating and mate choice.
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Animals↗
Biomedical subjects
P Cook
Publications and source records attributed to P Cook.
Immediate and delayed complications of epidural analgesia in labour and delivery.
A prospective controlled, longitudinal study investigated the immediate and delayed complications of epidural analgesia in labour. One hundred and twenty-two parturients were studied: 81 had epidurals in labour and 41 had other forms of analgesia. Each parturient was studied over a period of 6 weeks. Epidural analgesia in labour and delivery is generally safe. Although the epidural group recorded more complications, they tended to be minor ones such as backache, headaches, shoulder and neck pain. Epidural blocks have an added advantage of being helpful in complicated labours like breech presentations, multiple pregnancies, pre-eclampsia, in situations where caesarean section is anticipated and in manual removal of the placenta.
Journal Article↗
Predicting the outcome of twin block functional appliance treatment: a prospective study.
A prospective study was undertaken to investigate the relationship between various measured pre-treatment parameters and the reduction in overjet achieved when using a twin block functional appliance. Forty-three subjects were fitted with a twin block functional appliance, and a number of pre-treatment clinical and radiographic morphological features were recorded. The functional appliance wear was monitored for 6 months and any individual who did not co-operate with wear was excluded from the subsequent analysis. Multiple regression analysis with stepwise inclusion was used to relate the percentage reduction in overjet achieved by functional appliance wear to any of the pre-treatment parameters. The data from 22 individuals was included in the final analysis. The overbite and SNB angle were the most strongly related variables to percentage reduction in overjet. These were then used to construct a predictive equation for the expected percentage reduction in overjet: Percentage reduction in overjet in 6 months = 132 + 4.9x1 - 1.4x2, where x1 = overbite and x2 = SNB. The pre-treatment overbite was, in isolation, the most influential feature in predicting the percentage of overjet reduction.
Adolescent↗
Use of real-time PCR and fluorimetry to detect lamivudine resistance-associated mutations in hepatitis B virus.
Very rapid amplification of DNA by PCR in small volumes can be continuously monitored by the detection of the binding of probes with a rapid cycler with built-in fluorometric detection. Primers were designed to amplify approximately 100 bp of the polymerase gene of hepatitis B virus (HBV) spanning codon 550, where mutations associated with resistance to lamivudine invariably occur. Four hybridization probes were synthesized: one was 3' labelled with fluorescein and hybridized upstream of codon 550. The others were 5' labelled with Cy5 and 3' labelled with biotin and spanned codon 550. The Cy5-labelled oligonucleotides contained either wild-type (ATG) or mutant (GTG or ATT) sequences. A Cy5-labelled probe and either the fluorescein-labelled probe or Sybr Green 1 (a compound that fluoresces when bound to double-stranded DNA) were included in each PCR. After completion of the amplification by using a LightCycler (Idaho Technology), the temperature at which the Cy5 probe melted from the product was determined in a melt program that took ca. 3 min. Pre- and posttreatment samples from eight patients (five chronic and three transplant) who failed lamivudine treatment were amplified, and the presence of mutations in codon 550 was determined by ABI sequencing and by using the LightCycler; in some cases PCR products were also cloned, and multiple clones were sequenced. Concordant results were obtained in all cases. We found the LightCycler to be better at resolving the sequences of genomic mixtures; for example, two samples showed a sequence at codon 550 of (A/G)T(G/T), which was found by fluorimetry to be mixtures of GTG and ATT but no ATG, and this finding was confirmed by the sequencing of clones. However, this approach was not more sensitive than population sequencing for the detection of the presence of mixtures. Overall, this pilot study has demonstrated an approach that could be an extremely rapid and economical method for the detection of lamivudine resistance-associated mutations in HBV.
Anti-HIV Agents↗
Update on some aspects of the use of epidural analgesia in labour.
The aim of the study was to investigate the effect of epidural analgesia on blood pressure, duration of the second stage and mode of delivery. In a prospective controlled study carried out in a district general hospital, 122 parturients made up the study population; 81 had epidural blocks and 41 had other forms of analgesia during labour. Data were collated using questionnaires within 48 hours of delivery: 58/81 (71.6%) of those who chose epidural were primigravidae compared with 14/41 (34%) in the non-epidural group (p < 0.001). During labour, minimum diastolic blood pressure was significantly lower in the epidural group: 65.8 versus 72.4 mmHg (p = 0.003). Mean duration of the second stage of labour was significantly longer in the epidural group: 108.3 versus 41.6 minutes (p < 0.0001); 28/81 (34.6%) of the epidural group had operative vaginal deliveries compared with 6/41 (14.6%) of the non-epidural group (p = 0.0004). Epidural analgesia provides an effective form of pain relief in labour, which has a particularly strong appeal to primigravidae. It has a hypotensive effect which can be put to beneficial effect in hypertensive disease of pregnancy, but is significantly associated with a lengthened second stage of labour, resulting in an increased operative vaginal delivery rate.
Adolescent↗
Analysis of hepatitis B virus quasispecies changes during emergence and reversion of lamivudine resistance in liver transplantation.
This report describes nucleotide sequence analysis of part of the polymerase gene of hepatitis B virus (HBV) during the development of lamivudine-resistant HBV in five patients who received lamivudine treatment in conjunction with liver transplantation. Samples from patients were analysed before, during and after drug treatment in conjunction with serum HBV quantification by PCR. Lamivudine resistance was found to be associated with L526M and M550V changes in two patients and M550I change in three patients. Other changes associated with lamivudine resistance in some patients were V509I, A546V, S565A and A568T. The effects on HBV surface antigen are also described. Some patients were subsequently treated with famciclovir and/or ganciclovir with variable outcomes. In two out of three patients who stopped lamivudine treatment, reversion (partial or complete) to wild-type virus was observed after about 5 months. In contrast, a complex mixture of mutant viruses emerged in a third patient who stopped lamivudine treatment.
Antiviral Agents↗
Laparoscopy in 533 patients with abdominal malignancy.
BACKGROUND: Laparoscopy in patients with intra-abdominal malignancy remains controversial. This study evaluates the incidence of tumor recurrence at the port site after laparoscopy in patients with intra-abdominal malignancy. METHODS: The medical records of all patients with nongynecologic malignancies who underwent laparoscopic procedures between May 1, 1990, and June 30, 1996, at the University of Texas M.D. Anderson Cancer Center were reviewed. Data on extent of tumor, histologic findings, primary location, procedures performed, and complications were recorded. RESULTS: During this time, 533 patients with known intra-abdominal malignancies underwent laparoscopy. Mean follow-up time was 13.2 +/- 0.5 months (range 1 to 71 months; median 10.6 months). Four recurrences at the port site were identified (0.8%). Three of these patients had advanced intra-abdominal disease at the time of laparoscopy; 1 patient without advanced disease at the time of laparoscopy had a recurrence at the port site as the only site of recurrent disease (0.19%). The incidence of port site recurrences among patients with advanced intra-abdominal disease at the time of laparoscopy (3/71) was significantly greater than the risk of development of a recurrence at the port site among patients without advanced intra-abdominal disease at the time of laparoscopy (1/462; P < .0003, by chi-square analysis). CONCLUSION: Recurrence at the port site is very rare. When implantation at the port site does occur, it is most commonly associated with advanced intra-abdominal disease.
Abdominal Neoplasms↗
Phenotypic difference between Bcg(r) and Bcg(s) macrophages is related to differences in protein-kinase-C-dependent signalling.
Mice of diverse genetic backgrounds may be classified as being either resistant or susceptible to infection with Mycobacteria. These phenotypes appear to be determined by a single gene on chromosome 1, the Bcg gene, and are expressed at the level of the macrophage in vitro. When compared to macrophages from mice of the susceptible phenotype (Bcg[s]), macrophages from mice of the resistant phenotype (Bcg[r]) show enhanced functional properties including increased expression of MHC class II molecules, increased nitric oxide production, and greater capacity to inhibit the growth of several intracellular pathogens. The bacteriostatic activity of B10R and B10S macrophages correlated with the amount of nitric oxide produced by the macrophages. Since protein kinase C (PKC) has been shown to be involved in the induction of a range of macrophage functional activities, experiments were conducted to examine the possibility that phenotypic differences between Bcg(r) and Bcg(s) macrophages may be related to differences in PKC-dependent signalling. Macrophage cell lines were derived from mice congenic at the Bcg locus that are either resistant (B10R) or susceptible (B10S) to infection with Mycobacteria. In the basal state, PKC-specific activity was significantly increased in the cytosolic fractions of B10R cells when compared to B10S cells. Following phorbol myristate acetate (PMA) treatment and following the stimulation with Mycobacteria bovis BCG, PKC-specific activity increased significantly in membrane fractions of both B10R and B10S cells, but the absolute level was significantly greater in particulate fractions from B10R macrophages. Furthermore, B10R cells had a superior ability to phosphorylate endogenous substrates compared to B10S macrophages. Scatchard analysis of phorbol ester receptors revealed no differences between B10R and B10S cells. In contrast, the sensitivity of partially purified PKC from B10S cells to activation in vitro by diacylglycerol was decreased by approximately 50% when compared to enzyme from B10R cells. Western-blotting analysis using antibodies specific for PKC isoforms (alpha, beta, delta, epsilon, zeta and eta) showed similar levels of PKC isoforms present in B10R and B10S cells. To examine whether differences in PKC activity of B10R and B10S cells had functional consequences, the induction of c-fos gene expression was compared in the two cell lines. In response either to infection with M. bovis BCG or to stimulation with PMA, c-fos mRNA levels in B10R macrophages were increased 2-4-fold in comparison to B10S macrophages. Since we have previously found that the bacteriostatic activity of B10R and B10S macrophages correlated with the amount of nitric oxide produced by the macrophages, we have tested if the enhancement of PKC activity in these macrophages affects their ability to produce nitric oxide. We have found that interferon-gamma-(IFNgamma)-induced secretion of nitric oxide by B10R macrophages could be augmented a few fold by the activation of PKC whereas, in B10S macrophages stimulated with IFNgamma, nitric oxide release could be augmented by only about 10-20%. These results indicate that the differences in PKC activity between B10R and B10S macrophages may contribute to altered responsiveness to IFNgamma that results in different production of effector molecules crucial for bacteriostatic activity against M. bovis BCG.
Animals↗
Philadelphia-negative chronic myelogenous leukemia in a patient with a unique complex translocation: 46,XY,t(9;12;15)(q34;12;q21).
Chronic myelogenous leukemia (CML) is associated with an acquired karyotypic abnormality, the Philadelphia (Ph) chromosome, in 95% of cases. The Ph chromosome is the product of a balanced translocation that results in a hybrid gene that is considered essential for the pathogenesis of this disease. We have found a complex translocation involving chromosomes 9, 12, and 15 in a 42-year-old Haitian male with the clinical findings of CML. Complex translocations have been shown to result in the masking of the Ph chromosome. We used a mixture of two BCR-specific DNA probes for Southern blot analysis in order to test this hypothesis in our patient. High-molecular weight DNA was digested with the restriction enzymes BglII, BamHI and HindIII. The BglII digestion revealed the presence of two abnormal fragments of 3.9 and 3.0 kb and the BamHI digestion an abnormal 15-kb fragment. These data suggest there is a breakpoint in region 2 of M-bcr. The identification of this breakpoint confirms our hypothesis that a rearrangement involving 22q11 has occurred in the leukemic cells of our patient. A secondary translocation involving chromosomes 12 and 15 has hidden the effects of this translocation. Combined cytogenetic and molecular analysis establishes the karyotype of our patient as 46,XY,t(9;12;15;22)(q34;q12;q21;q11).
Adult↗
The ectopic maxillary canine: a case report.
A case is described of a severely ectopic maxillary canine, which underwent initial spontaneous improvement, and following extraction of the deciduous canine erupted satisfactorily. It provides a cautionary tale when considering surgical removal of ectopic maxillary canines.
Child↗
Toxic equivalency factors (TEFs) for PCBs, PCDDs, PCDFs for humans and wildlife.
An expert meeting was organized by the World Health Organization (WHO) and held in Stockholm on 15-18 June 1997. The objective of this meeting was to derive consensus toxic equivalency factors (TEFs) for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and dioxinlike polychlorinated biphenyls (PCBs) for both human, fish, and wildlife risk assessment. Based on existing literature data, TEFs were (re)evaluated and either revised (mammals) or established (fish and birds). A few mammalian WHO-TEFs were revised, including 1,2,3,7,8-pentachlorinated DD, octachlorinated DD, octachlorinated DF, and PCB 77. These mammalian TEFs are also considered applicable for humans and wild mammalian species. Furthermore, it was concluded that there was insufficient in vivo evidence to continue the use of TEFs for some di-ortho PCBs, as suggested earlier by Ahlborg et al. [Chemosphere 28:1049-1067 (1994)]. In addition, TEFs for fish and birds were determined. The WHO working group attempted to harmonize TEFs across different taxa to the extent possible. However, total synchronization of TEFs was not feasible, as there were orders of a magnitude difference in TEFs between taxa for some compounds. In this respect, the absent or very low response of fish to mono-ortho PCBs is most noticeable compared to mammals and birds. Uncertainties that could compromise the TEF concept were also reviewed, including nonadditive interactions, differences in shape of the dose-response curve, and species responsiveness. In spite of these uncertainties, it was concluded that the TEF concept is still the most plausible and feasible approach for risk assessment of halogenated aromatic hydrocarbons with dioxinlike properties.
Animals↗
Effect of time between farm loading and processing on carcase quality of broiler chickens.
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Animal Husbandry↗
A Bayesian analysis of regression models with continuous errors with application to longitudinal studies.
We employ a regression model with errors that follow a continuous autoregressive process to analyse longitudinal studies. In this way, unequally spaced observations do not present a problem in the analysis. We employ a Bayesian approach, where our inferences are based on a direct resampling process that generates values from the posterior distribution of the parameters of the model. We illustrate these Bayesian inferences with an analysis of a longitudinal study that involves the regression of foetal head circumference on menstrual age. Using these same data, we contrast the Bayesian approach with a maximum likelihood technique.
Bayes Theorem↗
Prognostic factors for patients with advanced seminoma treated with platinum-based chemotherapy.
Prognostic factors for 3-year progression-free survival (PFS) were defined in 286 patients with advanced seminoma treated with cisplatin-based chemotherapy at 10 European oncology units (no prior treatment: 236; prior radiotherapy: 50). Previously irradiated patients displayed a 69% PFS as compared to 87% in those presenting with advanced seminoma at the time of diagnosis (P = 0.009). In the univariate analysis, the extent and site of disease before chemotherapy and the level of serum LDH (< 2.0 versus > or = 2.0 x upper limit of normal) correlated with PFS in previously non-irradiated patients, but not in patients with prior radiotherapy. The multivariate analysis was, therefore, restricted to previously non-irradiated patients. The presence of non-pulmonary visceral metastases and a serum LDH level of > or = 2 x normal (N) proved to be independent prognostic factors. Based on these variables, two prognostic models were constructed and validated in an external data set of 166 comparable patients. For clinical use, Model 2 is recommended. The good-prognosis group comprises non-irradiated patients with stage II seminoma and any LDH level at presentation, or stage III and IV patients (with lung metastases only) whose serum LDH level is < 2 x N. These patients display a 94% 3-year PFS. The poor prognosis group includes all other patients with a 56% PFS. With this prognostic model, individualisation of the therapeutic approach may be considered in patients with advanced seminoma and a high risk of chemotherapy-related toxicity.
Adult↗
Treatment of recurrent malignant glioma with BCNU-fluosol and oxygen inhalation. A phase I-II study.
OBJECTIVES: To evaluate the toxicity and response rate following BCNU with oxygen inhalation and escalating dosages of fluosol administered to patients with radiographic progression of malignant glioma after definitive surgery and radiotherapy. METHOD: This single arm, phase I-II multicenter trial, enrolled 99 patients with malignant gliomas recurrent after definitive surgery and radiotherapy. All patients received a fixed dose (200 mg/m2) of BCNU along with 100% oxygen and fluosol, a perfluorochemical. Fluosol doses were escalated between patients (150, 275, 400 and 600 ml/m2). Treatment was repeated every 6 weeks for a maximum of 6 cycles. Patients were assessed for toxicity at the time of infusion and sequentially thereafter. Response was evaluated clinically and radiologically at least every 6 weeks. RESULTS: Treatment was well tolerated. Dose reductions were required at least once in 18 patients, treatment delays were necessary at least once in 33 patients. Grade 3-4 leukopenia occurred in 6 patients (12 events), grade 3-4 thrombocytopenia in 10 patients (25 events) and grade 3-4 liver enzymes elevations in 18 patients (31 events). Higher fluosol dosages did not produce increases in toxicity or responses. Response or stabilization was seen in 57% (38% were stabilizations) of the patients who entered the trial with progressive disease. The median time to progression was 45 weeks, and median survival was 66 weeks for patients who had response or stabilization. For patients with glioblastoma response/stabilization was seen in 45% with a mean duration of 24 weeks, for patients with anaplastic astrocytoma response/stabilization was seen in 68% with a mean duration of 50 weeks. CONCLUSION: This treatment regimen is well tolerated. Our results suggest fluosol may enhance the effectiveness of BCNU for the treatment of recurrent malignant gliomas. Future studies will be performed using fluosol at the dose of 400 ml/m2.
Adolescent↗
Single and double autotransplants for relapsing/refractory Hodgkin's disease: results of two consecutive trials.
To evaluate a strategy of one cycle of dose-intensive chemotherapy for patients with Hodgkin's disease in sensitive relapse and two cycles for those with refractory disease, 122 patients received dose-intensive chemotherapy followed by autotransplant in two consecutive studies. Patients with refractory disease were offered a second transplant with different conditioning in the absence of progression or excessive toxicity. CR was present after treatment in 46% while 16% died in the peritransplant period. Of 41 patients with primary refractory disease and 42 with refractory relapse, 24 and 21 respectively received a second cycle. Of these 45 refractory patients, 12 were in CR and 11 in PR after the first cycle and 10 of these 11 in PR achieved a durable CR with the second transplant. The CR rate is 37% in patients with refractory relapse and 19% in those with primary refractory disease. At a median follow-up of 4 years, median survival is 45 months. Progression-free survival of the refractory patients who could receive a second cycle was similar to that of patients with sensitive disease. A sequential transplant strategy is feasible. A subgroup of patients with refractory disease can achieve long-term survival after sequential BMT.
Adolescent↗
Sheet plastination as a clinically based teaching aid at the University of Auckland.
As a concerted move toward closer integration of the clinical and preclinical aspects of the undergraduate medical curriculum at the University of Auckland, the Department of Anatomy with Radiology has implemented a number of clinical procedures, pathological observations and diagnostic methods into the course resulting in a structured program of clinically based teaching of gross anatomy to second- and third-year medical students. The recently developed method of E12 epoxy resin sheet plastination of sectioned cadaver specimens has expanded the learning process twofold, firstly as a developmental microscopy teaching aid enabling us to link histological slides directly to gross anatomical specimens and secondly as a radiographic training tool in the correlation of clinical imaging techniques of magnetic resonance (MRI) and computed tomography (CT) with the teaching of gross anatomy. The direct comparison between E12 serial sectioned cadaver specimens and the equivalent MRI and CT images provides the student with a much clearer understanding of anatomical structures in relation to clinical diagnosis.
Aged↗