Determination by liquid chromatography-mass spectrometry of clomiphene isomers in the plasma of patients undergoing treatment for the induction of ovulation

A rapid, sensitive and selective LC-MS method is described for the simultaneous determination of zuclomiphene and enclomiphene in plasma from patients undergoing treatment with clomiphene citrate for the induction of ovulation. Samples spiked with N-didesmethyltamoxifen, the internal standard, were extracted into methyl tertiary butyl ether. The compounds were separated on a Luna C(18) analytical column, and a mobile phase of methanol-water (70:30 v/v) containing 0.05% trifluoroacetic acid at a flow rate of 1ml/min. The limits of determination were 35pg/ml and 7pg/ml for zu- and enclomiphene, respectively. Within-day coefficients of variation ranged from 2.1% to 7.2%.

An evaluation of current diagnostic tests for the detection of infectious salmon anaemia virus (ISAV) following experimental water-borne infection of Atlantic salmon, Salmo salar L

Four commonly used diagnostic tests [reverse transcription polymerase chain reaction (RT-PCR), indirect fluorescent antibody test (IFAT), virus culture and light microscopy] were evaluated for their ability to detect infectious salmon anaemia virus (ISAV) or tissue pathology following experimental infection of Atlantic salmon. Fish were infected with ISAV by water-borne exposure which mimics the route of natural infection. Forty-five per cent of pre-clinical fish tested yielded positive results by RT-PCR for at least one of the organs tested (kidney, heart, gill, liver, blood). No significant difference was detected between organs in the number or time of first occurrence of positive result. Virus culture identified a total of 14% of pre-clinical fish as ISAV-infected. The presence of ISAV in heart tissue was particularly notable (13% of fish sampled) as was the inability to culture virus from spleen tissue. In the case of IFAT, 15% of fish sampled were positive, although tissue other than kidney proved unsuitable for use in this method. Only limited ISAV-specific pathology was detectable by histological examination of fish prior to the onset of clinical disease. These findings reveal important information regarding the optimal choice of both tissue sample and diagnostic test for the routine diagnosis of ISAV.

Determination of midazolam and 1'-hydroxymidazolam by liquid chromatography-mass spectrometry in plasma of patients undergoing methadone maintenance treatment

A rapid, sensitive and selective LC-MS method was developed for the simultaneous determination of midazolam (MDZ) and 1'-hydroxymidazolam (1'-OHMDZ) in plasma taken from 54 patients undergoing methadone maintenance therapy, most of whom were multidrug users. Samples spiked with prazepam, the internal standard, and were extracted into diethyl ether. Compounds were separated on a Phenomenex Luna C(18) column and a mobile phase of acetonitrile-ammonium acetate buffer (10 mM, pH 4.7) (52:48, v/v) at a flow-rate of 1 ml/min. The limit of detection was 0.65 and 0.68 (ng/ml) for MDZ and 1'-OHMDZ, respectively. Within-day relative standard deviations were less than 8%.

Detection of infectious salmon anaemia virus (ISAV) by in situ hybridisation

An in situ hybridisation method was developed to detect infectious salmon anaemia virus (ISAV) in fixed tissues from Atlantic salmon Salmo salar L. Three DNA probes detected ISAV in heart, liver, kidney, spleen, caeca, and mid-gut from infected farmed Atlantic salmon obtained from a natural outbreak of ISA. The strongest signals were obtained using Probe S8, from Segment 8 of ISAV. Hybridisation was most prominent in the endothelial cells of heart tissue. The probes reacted specifically with ISAV; no hybridisation was evident in uninfected tissues from Atlantic salmon. Importantly, the probes did not cross react with the pathogens IHNV (haematopoietic necrosis virus), IPNV (infectious pancreatic necrosis virus), SPDV (salmon pancreas disease virus) and VHSV (viral haemorrhagic septicemia virus).

Infectious salmon anaemia virus in wild fish from Scotland

Following the outbreak of infectious salmon anaemia (ISA) at salmon farms in Scotland, UK, a survey was established to determine the extent of infection in wild fish. All fish tested were free from the clinical symptoms of ISA. Isolations of ISAV were made from 5 sea trout within areas where ISA affected salmon farms were located. Evidence for ISAV in other sea trout was provided by ISA RT-PCR diagnostic tests. Results from ISA RT-PCR tests reveal evidence for ISAV being present in salmon parr, adult salmon and juvenile brown trout in rivers distant from salmon farms and indicate that, at the time of the survey (1998-1999), ISAV may have been widely distributed. Nucleotide sequence analysis of segments 2 and 8 showed that for most sequences from wild fish there was 100% homology with ISAV isolated from clinically affected farmed fish although evidence is presented which indicates variability in ISAV sequences from wild fish. Modelling the RT-PCR findings indicates that ISAV among salmonid fish was spatially non-random. Brown trout, sea trout and salmon (adult and parr) show a pattern of occasionally large numbers of positive samples against a background of very low numbers.

The antitussive effect of dextromethorphan in relation to CYP2D6 activity

AIMS

To test the hypothesis that inhibition of cytochrome P450 2D6 (CYP2D6) by quinidine increases the antitussive effect of dextromethorphan (DEX) in an induced cough model.

METHODS

Twenty-two healthy extensive metaboliser phenotypes for CYP2D6 were studied according to a double-blind, randomised cross-over design after administration of: (1) Placebo antitussive preceded at 1 h by placebo inhibitor; (2) 30 mg oral DEX preceded at 1 h by placebo inhibitor (DEX30); (3) 60 mg oral DEX preceded at 1 h by placebo inhibitor (DEX60); (4) 30 mg oral DEX preceded at 1 h by 50 mg oral quinidine sulphate (QDEX30). Cough frequency following inhalation of 10% citric acid was measured at baseline and at intervals up to 12 h. Plasma concentrations of DEX and its metabolites were measured up to 96 h by h.p.l.c.

RESULTS

Inhibition of CYP2D6 by quinidine caused a significant increase in the mean ratio of DEX to dextrorphan (DEX:DOR) plasma AUC(96) (0.04 vs 1.81, P<0.001). The mean (+/-s.d.) decrements in cough frequency below baseline over 12 h (AUEC) were: 8% (11), 17% (14.5), 25% (16.2) and 25% (16.9) for placebo, DEX30, DEX60 and QDEX30 treatments, respectively. Statistically significant differences in antitussive effect were detected for the contrasts between DEX60/placebo (P<0.001; 95% CI of difference +80, +327) and QDEX30/placebo (P<0.001, +88, +336), but not for DEX30/placebo, DEX30/DEX60 or DEX30/QDEX30 (P=0.071, -7, +241; P=0.254, -37, +211; P=0.187, -29, +219, respectively).

CONCLUSIONS

A significant antitussive effect was demonstrated after 60 mg dextromethorphan and 30 mg dextromethorphan preceded by 50 mg quinidine using an induced cough model. However, although the study was powered to detect a 10% difference in cough response, the observed differences for other contrasts were less than 10%, such that it was possible only to imply a dose effect (30 vs 60 mg) in the antitussive activity of DEX and enhancement of this effect by CYP2D6 inhibition.

The relationship between anthropometric measurements at birth: asthma and atopy in childhood

BACKGROUND

Recent studies have reported that a large head circumference at birth is associated with an increased risk of raised serum IgE in adult life, and asthma during childhood.

OBJECTIVE

To examine the relationship between head circumference and other anthropometric measurements at birth and asthma and indices of atopy in childhood.

METHODS

The presence of asthma and measures of atopic status (total serum IgE level and skin prick tests to common allergens) were assessed prospectively in offspring of families participating in a community-based genetic study in Southampton, UK. Measures of perinatal variables including birth weight, head circumference at birth, and gestational age were obtained from hospital records of 239 offspring aged 6-23 years.

RESULTS

Children with a head circumference of 37 cm or more at birth had a relative risk of an elevated serum total IgE (> 150 IU) of 3.2 (95% CI 1.0-10.4). There were no consistent relationships between head circumference at birth and either skin prick positivity or the development of clinical asthma. There was no significant association between other perinatal markers and measures of atopic status or clinical asthma.

CONCLUSION

The study has identified that a large head circumference at birth is associated with an increased risk of an elevated total serum IgE in childhood. The reasons for this association, and the lack of an association with asthma are unclear and will require further research.

The so-called "placebo effect" in benign prostatic hyperplasia treatment trials represents partially a conditional regression to the mean induced by censoring

OBJECTIVES

To study the variability of assessment instruments (symptom questionnaires and flow rate recordings) in healthy volunteers during repeat administration in short intervals. To study the effect of inclusion criteria-based censoring of patients during screening for benign prostatic hyperplasia (BPH) treatment trials on the outcome of subsequent tests.

METHODS

One hundred forty-five male volunteers without known prostatic diseases with a mean age of 52 years (range 23 to 83) were given the American Urological Association (AUA) Symptom Index (SI), BPH Impact Index (II). Quality of Life (QOL) score, and a flow rate recording twice 10 to 20 days apart without any healthcare intervention. Data were collected and analyzed after typical BPH trial criteria were applied to the first test, and patients who did not "qualify" were censored.

RESULTS

Good correlation exists between two closely spaced administrations of the AUA SI, BPH II, QOL score, and flow rate recordings in healthy male volunteers with correlation coefficients between 0.73 and 0.89. Censoring patients and excluding them from the analysis of the second test based on typical BPH trial criteria induces a regression to the mean phenomenon, which results in an artificial improvement in these outcome parameters. The magnitude of the improvement increases as the selection and censoring criteria tighten. The mean differences between the first and second test range from 1.4 to 1.7 mL/s for the peak flow rate, from -1.0 to -1.4 for the AUA SI, and from -0.4 to -0.8 for the BPH II. All these differences induced solely by censoring with resulting regression to the mean are statistically significant.

CONCLUSIONS

Censoring of patients based on inclusion and exclusion criteria is typical for BPH treatment trials. One of the under-recognized effects of censoring is a regression to the mean, which leads to an apparent improvement in the outcome parameters assessed. In both placebo or sham-controlled trials, as well as in clinical series without controls, one must keep this effect and its relative magnitude in mind, and interpret the data from such trials with appropriate caution.

Intra-articular morphine and/or bupivacaine in the management of pain after total knee arthroplasty

The purpose of this study was to determine if intra-articular injection of morphine or bupivacaine significantly decreased postoperative pain as well as the use of intravenous narcotics for pain relief in patients undergoing total knee arthroplasty (TKA). In a prospective, double-blind, randomized fashion, 105 patients undergoing TKA were divided into the following 4 groups defined by the intra-articular injection they received: group 1 (n = 27) received saline solution, group 2 (n = 26) received morphine sulfate (5 mg), group 3 (n = 24) received bupivacaine (50 mg), and group 4 (n = 28) received a combination of morphine sulfate and bupivacaine. The injections were administered immediately after wound closure by the Hemovac drainage tubing that remained clamped for 45 minutes after surgery to allow for absorption. Before surgery and at 2, 4, 6, 24, and 48 hours after surgery, pain intensity was recorded using a visual analog scale. Postoperative supplemental intravenous morphine and/or meperidine was administered via a patient-controlled analgesia device, and 24-hour drug usage was tabulated. Results were suggestive of a modest short-term reduction in pain scores in the morphine and bupivacaine treatment groups compared with placebo (saline); however, results were statistically significant only at 4 hours because of the great variability in the pain score data. The total amount of postoperative pain medication used in the first 24 hours after surgery was not statistically significant between the 4 treatment groups. Thus, the results put into question the benefit of postoperative intra-articular administration of morphine or bupivacaine in patients undergoing TKA.

Comparison of three assays for total serum prostate-specific antigen and percentage of free prostate-specific antigen in predicting prostate histology

OBJECTIVES

To determine the statistical performance of three different assays for prostate specific antigen (PSA) and the percentage of free PSA with respect to the differentiation of histologic benign prostatic hyperplasia (BPH) and prostate cancer in men who underwent surgical removal of prostate tissue.

METHODS

Serum of 86 men scheduled for prostate surgery (transurethral resection of the prostate [TURP], simple open prostatectomy, radical prostatectomy, cystoprostatectomy) was frozen and subjected to measurement in batches using three different assays for total PSA (Hybritech Tandem-E, Abbott IMx, Tosoh AIA-600) and free PSA by the Hybritech method after a single freeze-thaw cycle. The histologic diagnosis of the removed tissue (35 BPH and 51 cancer) was used as a "gold standard" for classification of disease status. Sensitivity, specificity, positive and negative predictive values, and diagnostic efficiency were calculated for the three total PSA assays and the free/total PSA ratios for the entire cohort and subsets. Receiver-operating characteristic (ROC) curve analysis was used to compare the performance of the assays and ratios.

RESULTS

Mean and median total PSA values differed slightly between the three assays for all patients, and for those with BPH and cancer, but this difference was not significant. Because of a considerable overlap, the differences between the mean PSA values for men with BPH and prostate cancer were not significant. At a cutpoint of 4.0 ng/mL, sensitivity with respect to the differentiation between BPH and prostate cancer was 68.6% for all three total PSA assays; the respective AUCs (0.613-0.625) were not significantly different. While the performance of the free/total PSA ratios was superior, the differences were only significant when subsets of patients were considered with a total PSA between 4 and 10 ng/mL or 4 and 15 ng/mL (AUCs 0.789-0.816). Likewise, sensitivity, specificity, and diagnostic efficiency was better in these subsets of patients.

CONCLUSIONS

In this study in which a "gold standard" based on histologic analysis of the entire (or large part of) the prostate gland was used to classify disease status, the three assays for total serum PSA (Hybritech Tandem-E, Abbott IMx, and Tosoh AIA-600) performed very similarly with identical sensitivities (at a cutpoint of 4.0 ng/mL) and comparable AUCs with respect to the differentiation of men with histologic BPH and prostate cancer. The ratios of free/total PSA calculated as free PSA by the Hybritech manual immunoradiometric assay (IRMA) method over all three total PSA assays, performed marginally better in the entire patient population. However, in the subsets of patients with a PSA of 4-10 ng/mL and 4-15 ng/mL, all three ratios performed significantly better than the three total PSA assays. The proper choice of a cutpoint for the ratio (15%, 17%, 19%, or 21%) depends on the desirability of maximizing either sensitivity or specificity while optimizing diagnostic efficiency.

Identifying the residential location of rapists

The spatial offence behaviour of 45 British serial rapists was examined in order to generate a predictive model, of use to criminal investigators. Two alternative hypotheses were explored. One predicted that rapists would commute into an area to carry out their offence. The second predicted that they would "maraud" out from a fixed location. Of the 45 offenders, 39 fitted the "maurader" hypothesis. However, the area covered by this model was an average of nearly 180 square miles. A second complementary theory, developed from facets of offenders' backgrounds, was therefore used to refine the predictions of distance travelled to and between offences. This enabled the size of the residential zone predicted from the marauder model to be reduced to a mean area of just over ten square miles. Tests of these models, combined into a small scale expert system, predicted the correct area for 82% of the cases. Suggestions for the further development of this expert system are discussed.

The three dimensional reconstruction and monitoring of facial surfaces

The study and monitoring of facial appearance is particularly important in the field of orthodontics and reconstructive maxillo-facial surgery. The introduction of new medical imaging techniques, such as X-ray computerized tomography (CT), has enabled surgery to be planned in three dimensions, compared with conventional methods using lateral and antero-posterior cephalographic images. Whilst it is possible to visualize bone and soft tissue structure the repeated use of CT scanning is undesirable because of the high doses of radiation involved. The research involves the development of a simple, low cost and non-invasive three-dimensional scanning method for facial surfaces. This is achieved using a technique known as structured light, using a standard commercial slide projector, CCD cameras and a framestore linked to a PC. The eventual aim is to provide clinicians a software assisted surgical procedure, by merging X-ray and skin data, allowing the manipulation of bone and soft tissue. This will give the facility to predict and monitor post-surgical appearance, detailing the effects of surgery benefiting both the clinician and patient. The research focuses on how the images are obtained using the scanning system and the subsequent image processing of data to give a realistic 3D image using a standard PC.

Detection of Haemonchus contortus surface antigen in faeces from infected sheep

An antigen capture enzyme-linked immunosorbent assay (ELISA) has been developed that could identify Haemonchus contortus antigens in dilute suspensions of worm homogenates and in faeces from sheep naturally infected with moderate burdens of the parasite. The ELISA is based on a polyclonal (rabbit or sheep) antibody coated solid-phase that captures parasite antigen from a suspension of worms or faeces. The captured antigen is detected by a mouse monoclonal antibody (MAb E2) that is reactive with a cuticle surface antigen of H. contortus. Binding of MAb E2 was shown to be specific for H. contortus and the ELISA was able to detect this antigen in faeces of some infected sheep. Characterisation of the antigen reacting with MAb E2 indicates it to be a collagenase and protease resistant surface protein of H. contortus that under reducing conditions in SDS-polyacrylamide gel electrophoresis exists as polypeptides of molecular weight 122, 56 and 49 kDa.

Plasma concentrations of the stereoisomers of prilocaine after administration of the racemate: implications for toxicity?

A chiral high pressure liquid chromatography method was developed to measure the separate isomers of prilocaine in plasma after administration of the racemate. The concentrations of the isomers in six patients were similar (S(+)/R(-) = 1.06 (SD 0.06)) after brachial plexus block with 1.5% (RS)-prilocaine hydrochloride 35 ml, suggesting that a higher systemic safety margin may not be achieved by substituting racemic prilocaine by one of its isomers. Much higher plasma concentrations of the S(+)- than the R(-)-form after oral administration of 300 mg of the racemate (n = 4) indicated a large difference in intrinsic metabolic clearance of the isomers on first pass through gut, liver or both organs.

Loss of pancreatic islet tolerance induced by beta-cell expression of interferon-gamma

Interferon-gamma (IFN-gamma) is produced during the response to infection and participates in immunostimulatory events. We have previously reported the induction of diabetes in transgenic mice (ins-IFN-gamma) in which the expression of the lymphokine IFN-gamma is directed by the insulin promoter. This diabetes is a result of the progressive destruction of pancreatic islets that occurs with the influx of inflammatory cells. Here we demonstrate that this islet cell loss is mediated by lymphocytes, that engrafted histocompatible islets are destroyed, and that lymphocytes from the transgenic mice are cytotoxic to normal islets in vitro. These results indicate that the pancreatic expression of IFN-gamma can result in a loss of tolerance to normal islets, consistent with its role as an inducer of costimulatory activity, which is essential for lymphocyte activation during an immune response.

Tuberculosis in captive seals: bacteriological studies on an isolate belonging to the Mycobacterium tuberculosis complex

Culture of tuberculous lesions from six of 14 captive seals yielded an organism which, on the basis of biochemical and drug sensitivity tests, was identified as Mycobacterium bovis, although the organism showed a weak cording pattern and was glycerol tolerant. It was pathogenic in rabbits and guinea pigs and after passage the organism exhibited strong cord formation and was glycerol intolerant. Restriction endonuclease analysis and sodium dodecyl-sulphate polyacrylamide gel electrophoresis indicated that the organism belonged to the Mycobacterium tuberculosis complex. Restriction patterns indicated that infection in the six seals was from a single source. Western blotting with monoclonal antibody to M bovis identified antigens at 23 and 27 kDa in M bovis which were absent from the seal isolates.

A feasibility study of a new approach to clinical radiosensitisation: hypothermia and hyperbaric oxygen in combination with pharmacological vasodilatation

It is proposed that hyperbaric oxygen fails in the clinical situation due to a high proportion (greater than 33%) of hypoxic cells in human tumours. The means of overcoming this problem are reviewed. Additional to hyperbaric oxygenation, moderate hypothermia (30 degrees C) to allow redistribution of oxygen in the tumour is proposed. A system of externally controlled intravenous anaesthesia has been developed for the single-subject hyperbaric cylinder. Pharmacological vasodilatation is induced in the anaesthetised patient who is then fluid loaded and cooled. Initial single-sensitising treatments are advocated. Twenty-nine patients with advanced mouth cancer have completed a course of this treatment, of whom five of nine were free of disease after 2 years and 10 of 21 at 1 year, with three intercurrent deaths. Fifteen have experienced local failure. This approach would appear to be practical, safe and promising.