Use of the 2A sequence from foot-and-mouth disease virus in the generation of retroviral vectors for gene therapy

We describe the construction of retroviral plasmid vectors in which two genes are linked by a minimum of 96 nucleotides encoding the 2A sequence from the picornavirus foot-and-mouth disease virus (FMDV). Transcription and translation gives rise to a bicistronic mRNA and two independent protein products. The system offers advantages to other alternative ways to create polycistronic mRNAs and can be used in gene therapy delivery vectors.

An estimate of the proportion of diarrhoeal disease episodes seen by general practitioners attributable to rotavirus in children under 5 y of age in England and Wales

Mean weekly incidence rates for a 4-week period of new episodes of infectious intestinal disease (IID) and laboratory reports of faecal isolations in children under 5 y of age presenting in general practice were used to estimate the incidence of IID due to rotavirus infection in England and Wales. Between January 1992 and December 1996, a total of 92452 new episodes of IID were seen at sentinel general practices and reported to the Royal College of General Practitioners (RCGP) Research Unit in Birmingham, UK. Of these 32% (29592) were in children under 5 y of age. During the same period the Communicable Disease Surveillance Centre (CDSC) in London, UK received 159532 reports of faecal identifications in children under 5 y of age; 69219 (43%) of these were due to rotavirus. By modelling RCGP data and laboratory reports, the proportion of episodes attributable to rotavirus infection was estimated to be 29% (95% CI: 24% to 34%). By extrapolation of RCGP data it was estimated that rotavirus accounted for 762000 of new episodes of IID nationally in children under 5 y of age between January 1992 and December 1996. Implementation of a rotavirus vaccination programme could substantially reduce the incidence of childhood diarrhoea.

Use of a broad-host-range bacteriocin-producing Lactococcus lactis transconjugant as an alternative starter for salami manufacture

Lactococcus lactis DPC4268 is widely used for Cheddar cheese manufacture in Ireland where it is recognised for its reliable fast acid producing ability in dairy environments. A transconjugant of this strain, L. lactis DPC4275, was generated which produces the broad spectrum, two-component bacteriocin lacticin 3147, which is inhibitory to a variety of undesirable gram-positive bacteria including Clostridium, Bacillus, Enterococcus, Listeria, Staphylococcus and Streptococcus. Both DPC4268 and DPC4275 were used as single strain starters for manufacture of salamis. These products were compared with a salami manufactured with a conventional starter (Lactobacillus sake and Staphylococcus carnosus) in terms of pH development, a(w)-value, weight loss, colour development and sensory characteristics. Salamis produced with either lactococcal culture exhibited pH values below 5.1 and a(w)-values below 0.90 which is favourable for preservation and hygienic stability. In addition, these salamis had good sensory and colorimetric qualities. A minimum lacticin 3147 concentration of 640 AU/g was detected in the salamis which were produced with L. lactis DPC4275.

Menopausal status: subjectively and objectively defined

This study aims to assess the relationship between self-rated and menstrually defined menopausal status, assesses criteria women use in perceiving their own menopausal status and compares symptom reporting and hormonal levels for self-rated and menstrually defined menopausal status. Women in the third year of the longitudinal phase of the Melbourne Women's Midlife Health Project (n = 332) were asked to assess their own menopausal status and the basis for this assessment. They were also specifically questioned on current menstrual cycle characteristics and levels of follicle-stimulating hormone (FSH), estradiol and inhibin were measured. For 67% of the women, the two definitions of menopausal status were in agreement. In women menstrually defined as premenopausal, self-rated menopausal status of peri- or postmenopausal appeared to be based on the occurrence of symptoms. In women menstrually defined as postmenopausal, persistence of hot flushes was taken to mean that 'the menopause was still in progress' despite absence of menses for more than 12 months. In women menstrually defined as perimenopausal yet who self-rated as premenopausal, FSH was lower (p < 0.01) and inhibin higher (p = 0.05) than women who self-rated as peri- or postmenopausal. Women's perceptions of the menopause are based on symptoms. Self-rated menopausal status appears to relate more closely to a women's endocrine status than definitions based on purely menstrual cycle characteristics.

Atrial natriuretic peptide increases urinary albumin excretion in men with type 1 diabetes mellitus and established microalbuminuria

Raised plasma concentrations of atrial natriuretic peptide (ANP) have been reported in patients with Type 1 (insulin dependent) diabetes mellitus (DM) who have poor glycaemic control and are associated with the presence of microalbuminuria. To test the hypothesis that elevations in plasma ANP concentration increase urinary albumin excretion in Type 1 DM, we have studied the effects of intravenous infusions of ANP in eight such subjects with established microalbuminuria. Blood glucose was maintained between 4 and 7 mmol l-1 in all subjects for the duration of studies; after euglycaemia had been established, a standard oral water load (20 ml kg-1 plus replacement of urinary losses) was given. Once steady state diuresis was attained, subjects received intravenous infusion of either placebo (0.9% saline), low dose (2.5 pmol kg-1 min-1) or high dose (5.0 pmol kg-1 kg min-1) ANP solution in a randomized, double-blind protocol. Infusion of ANP caused a dose-dependent increase in urinary albumin excretion rate (placebo, 11.3 (SD 8.9) to 8.7 (SD 6.8) micrograms min-1; low dose ANP, 12.4 (SD 9.9) to 26.5 (SD 27.5) micrograms min-1, p < 0.01; high dose ANP 10.3 (SD 7.3) to 36.6 (SD 28.5) micrograms min-1, p < 0.001, ANOVA). Only high dose ANP caused an increase in urine flow. Blood glucose remained unchanged in all studies. We conclude that intravenous infusions of ANP cause a dose-dependent increase in urinary albumin excretion rate in Type 1 DM subjects with microalbuminuria. These data support the hypothesis that ANP has albuminuric actions which may contribute to microalbuminuria in Type 1 DM.

The pharmacokinetics of combination therapy with nelfinavir plus nevirapine

OBJECTIVE

To investigate the pharmacokinetics of nelfinavir (NFV) administered alone and in combination with nevirapine (NVP) to HIV-positive patients.

DESIGN

Seven patients with advanced HIV disease received dual nucleoside analogues in addition to NFV (750 mg three times daily) and subsequently NVP (200 mg daily for 2 weeks followed by 200 mg twice daily) as salvage therapy. On the first study day (day 3), blood samples were taken for assay of NFV. The second study day followed the introduction of NVP for 3 weeks.

METHODS

Blood samples were obtained at 0, 1, 2, 3, 4, 6 and 8 h after dosing on both study days. Separated plasma was heated to 58 degrees C for 30 min to inactivate HIV and stored at -80 degrees C until analysis by high performance liquid chromatography for both NFV and NVP.

RESULTS

The geometric mean NFV area under the concentration-time curve to 8 h (AUC0-8h) was 23.4 microg x h/ml (range, 13.5-49.2) and 11.6 microg x h/ml (range, 6.6-23.2) on the first and second study days, respectively. The geometric mean ratio was 0.49 (95% confidence interval, 0.33-0.72; P = 0.016). This represented a 50% reduction in plasma NFV concentrations. Maximum and minimum concentrations were also reduced during NVP therapy (from 4.4 to 2.5 microg/ml and from 1.7 to 0.8 microg/ml, respectively). Time to maximum concentration was reduced from 4 to 2 h. NVP concentrations were determined with a maximum concentration of 5.4 microg/ml at 4 h.

CONCLUSIONS

NVP is currently being used in combination therapy with protease inhibitors for antiretroviral-experienced patients in the setting of treatment failure. This study demonstrates that when patients are coadministered NVP there is a 50% reduction in the plasma AUC of NFV. Although the mean trough concentrations of NFV remained above the stated minimum effective concentration of 0.4 microg/ml, there is nevertheless concern that some patients will fall below this value when NVP is added to treatment regimens. In the absence of therapeutic drug monitoring we suggest that an increase in the standard NFV dosage of 750 mg three times daily will be required to ensure satisfactory NFV plasma concentrations, thereby maintaining antiviral efficacy.

Methodological issues in the application of conjoint analysis in health care

This paper adds to an increasing literature on methodological questions addressed in the application of conjoint analysis (CA) in health care. Three issues are addressed: ordering effects; internal validity; and internal consistency. The results of an application of CA in a primary care setting provide no evidence that the ordering of scenarios was important. Evidence was found of both internal validity and internal consistency. In addition, individual preferences were found to be determined by experiences, which raise potentially important questions regarding the elicitation and use of such preferences in economic evaluation.

Antibodies to oxidized lipoproteins and their relationship to myocardial infarction

The inflammatory process and autoimmunity in the form of antibodies to oxidized LDL are important factors in the formation of the atherosclerotic plaque. We examined the time relationship of oxidized lipoprotein antibodies to the acute oxidative stress of myocardial infarction (MI). We also examined the relationship of C-reactive protein, an index of inflammation, and therefore of free radical production, to oxidized low-density lipoprotein (LDL) antibodies. We examined five groups of patients in a cross-sectional study: group 1, within 48 h of MI; group 2, two days to 1 week; group 3, 1-4 weeks; group 4, 1-3 months; and group 5, 3-6 months post MI. Nine patients with high antibody levels were re-examined 12 months after their first assessment. Malondialdehyde (MDA)-LDL and MDA-HDL antibodies were determined by an ELISA method. The highest MDA-LDL antibodies were found within 48 h of MI, but there was no significant difference in MDA-HDL antibodies between the groups. When 9/10 patients with LDL antibodies greater than the mean of 2.7 were re-examined 1 year later, there was a significant decrease in the mean antibody levels (5.2 +/- 1.7 vs. 3.2 +/- 0.6, p < 0.02). There was no correlation between antibodies to MDA-LDL and antibodies to MDA-HDL. There was a positive correlation between serum HDL cholesterol and antibodies to MDA-LDL (r = 0.4, p < 0.02) and a positive correlation between serum triglycerides and MDA-HDL antibodies (r = 0.39, p < 0.02). Acute MI appears to be associated with significantly higher C-reactive protein and antibodies to MDA-LDL, suggesting a possible acceleration of the atherosclerotic process immediately prior to MI.

Successful use of protease inhibitors in HIV-infected haemophilia patients

The haemophilias are a group of inherited haemostatic disorders that require regular clotting factor replacement therapy in the severe and moderately severe subgroups. Prior to the introduction of adequate viral inactivation methods in 1985, haemophilia patients were at exceptionally high risk of contracting blood-borne viruses from factor concentrates as each batch was derived from the plasma of thousands of donors. As a result, approximately 60% of these patients were infected with HIV between 1979 and 1985, and HIV infection now contributes significantly to the morbidity and mortality seen in this group. Protease inhibitors (PIs) have been shown to significantly log reduce viral loads and increase CD4 cell counts in HIV-infected individuals. Recently, there has been concern about their use in HIV-infected haemophilia patients following increased bleeding episodes in some patients during PI therapy. We prospectively studied the effect of PI therapy in 20 HIV-infected haemophilia patients at our centre over a 6-month period. The mean increase in CD4 cell count was 70 x 10(6)/l and the mean log decrease in viral load was 1.59 over the study period. Gastrointestinal side-effects (nausea and vomiting in five, diarrhoea in two) were the most frequent and resulted in discontinuation of the medication in two patients. Factor concentrate usage for the group on and off study was similar. One severe FVIII patient reported a single episode of an unusual bleed which responded promptly to FVIII concentrate infusion. The significant clinical and laboratory benefits in terms of HIV disease and the paucity of added bleeding complications suggest that PI therapy should not be withheld from HIV-infected haemophilics. Further prospective studies evaluating the efficacy and possible haemostatic complications related to these promising inhibitors of the HIV protease are needed.

Pertussis toxin potentiates Th1 and Th2 responses to co-injected antigen: adjuvant action is associated with enhanced regulatory cytokine production and expression of the co-stimulatory molecules B7-1, B7-2 and CD28

Pertussis toxin (PT) is a major virulence factor of Bordetella pertussis which exerts a range of effects on the immune system, including the enhancement of IgE, IgA and IgG production, delayed-type hypersensitivity reactions, and the induction of experimental autoimmune diseases. However, the mechanism by which PT mediates adjuvanticity remains to be defined. In this investigation we have shown that PT can potentiate antigen-specific T cell proliferation and the secretion of IFN-gamma, IL-2, IL-4 and IL-5 when injected with foreign antigens. A chemically detoxified PT and a genetic mutant with substitutions/deletions in the S-1 and B oligomer components that abrogate enzymatic and binding activity displayed no adjuvant properties. In contrast, a non-toxic S-1 mutant devoid of enzymatic activity but still capable of receptor binding retained its adjuvanticity, augmenting the activation of both Th1 and Th2 subpopulations of T cells. In an attempt to address the mechanism of T cell activation, we found that PT stimulated the production of IFN-gamma and IL-2 by naive T cells and IL-1 by macrophages. Therefore potentiation of distinct T cell subpopulations may have resulted in part from the positive influence of IFN-gamma on the development of Th1 cells and the co-stimulatory role of IL-1 for Th2 cells. Furthermore, PT augmented expression of the co-stimulatory molecules B7-1 and B7-2 on macrophages and B cells, and CD28 on T cells, suggesting that the adjuvant effect may also be associated with facilitation of the second signal required for maximal T cell activation. This study demonstrates that the immunopotentiating properties of PT are largely independent of ADP-ribosyltransferase activity, but are dependent on receptor binding activity and appear to involve enhanced activation of T cells.

Use of systematic reviews of randomised trials by Australian neonatologists and obstetricians

OBJECTIVE

To determine what proportion of Australian neonatologists and obstetricians report using systematic reviews of randomised trials.

DESIGN

Cross-sectional survey using structured telephone interviews.

SETTING

Australian clinical practice in 1995.

PARTICIPANTS

103 of the 104 neonatologists in Australia (defined as clinicians holding a position in a neonatal intensive care unit); a random sample of 145 members of the Royal Australian College of Obstetricians and Gynaecologists currently practising in Australia.

MAIN OUTCOME MEASURES

Information sources used in clinical practice; reported awareness of, access to and use of systematic reviews, and consequent practice changes.

RESULTS

Response rates were 95% (neonatologists) and 87% (obstetricians); 71 neonatologists (72%) and 55 obstetricians (44%) reported using systematic reviews, primarily for individual patient care. Databases of systematic reviews were used with a median frequency of once per month. Among neonatologists, systematic reviews were used more commonly by those who were familiar with computers, attended professional meetings, and had authored research papers. Among obstetricians, they were used more commonly by those who were familiar with computers, had less than 10 years' clinical experience, attended more deliveries, and were full-time staff specialists in public hospitals. Of neonatologists who reported using systematic reviews, 58% attributed some practice change to this use. For obstetricians, the corresponding figure was 80%.

CONCLUSIONS

There is evidence that Australian neonatologists and obstetricians use systematic reviews and modify their practice accordingly. Dissemination efforts can benefit from knowledge of factors that predict use of systematic reviews.

A kinematic and kinetic analysis of the sit-to-stand transfer using an ejector chair: implications for elderly rheumatoid arthritic patients

Twelve elderly female rheumatoid arthritis patients (mean age = 65.5 +/- 8.6 yr) were assessed rising from an instrumented Eser Ejector chair under four conditions: high seat (540 mm), low seat (450 mm), with and without the ejector mechanism operating. Sagittal plane motion, ground reaction forces, and vertical chair arm rest forces were recorded during each trial with the signals synchronised at initial subject head movement. When rising from a high seat, subjects displayed significantly (p < 0.05) greater time to seat off; greater trunk, knee and ankle angles at seat off; increased ankle angular displacement; decreased knee angular displacement; and decreased total net and normalised arm rest forces compared to rising from a low seat. When rising using the ejector mechanism, time to seat off and trunk and knee angle at seat off significantly increased, whereas trunk and knee angular displacement, and total net and normalised arm rest forces significantly decreased compared to rising unassisted. Regardless of seat height or ejector mechanism use, there were no significant differences in the peak, or time to peak horizontal velocity of the subjects' total body centre of mass, or net knee and ankle moments. It was concluded that increased seat height and use of the ejector mechanism facilitated sit-to-stand transfers performed by elderly female rheumatoid arthritic patients. However, using the ejector chair may be preferred by these patients compared to merely raising seat height because it does not necessitate the use of a footstool, a possible obstacle contributing to falls.

Double-blind crossover study of the interaction between perindopril and amlodipine on blood pressure and hormones related to fluid and electrolyte balance in patients with essential hypertension

This study was to investigate the interaction between low doses of perindopril (2 mg daily) and amlodipine (2.5 mg daily) on ambulatory blood pressure (BP), clinic BP, serum angiotensin-converting enzyme (ACE), plasma levels of renin (PRA), angiotensin II (Ang II), aldosterone, and atrial natriuretic peptide (alpha-h ANP) in subjects with essential hypertension. The study design was a parallel, two-period, placebo-controlled, double-blind crossover design, with 11 subjects receiving perindopril and 10 receiving amlodipine during the run-in phase. The addition of amlodipine to perindopril had no effect on ambulatory BP, whereas the addition of perindopril to amlodipine reduced both systolic (P = 0.027) and diastolic (P = 0.049) ambulatory BP. By contrast, the opposite result was obtained for clinic BP at trough, whereby the addition of amlodipine to perindopril reduced erect systolic BP (P = 0.036) and both supine and erect diastolic BP (P = 0.038) whereas the addition of perindopril to amlodipine was without effect. The addition of perindopril to amlodipine decreased serum ACE by 72% and increased PRA two-fold, without change in plasma levels of Ang II, aldosterone or alpha-h ANP. The addition of amlodipine to perindopril increased plasma aldosterone 1.7-fold but did not affect serum ACE, PRA, Ang II, or alpha-h ANP. These interactions between perindopril and amlodipine may have been conditioned by the specific effects of the therapy first given, as well as by the different circumstances of BP measurement (ambulatory vs clinic).

A murine model in which protection correlates with pertussis vaccine efficacy in children reveals complementary roles for humoral and cell-mediated immunity in protection against Bordetella pertussis

The results of phase 3 efficacy trials have shown that acellular and whole-cell pertussis vaccines can confer protection against whooping cough. However, despite the advances in vaccine development, clinical trials have not provided significant new information on the mechanism of protective immunity against Bordetella pertussis. Classical approaches based on measurement of antibody responses to individual antigens failed to define an immunological correlate of protection. A reliable animal model, predictive of acellular and whole-cell pertussis vaccine potency in children, would facilitate an elucidation of the mechanism of immune protection against B. pertussis and would assist in the regulatory control and future development of pertussis vaccines. In this study, we have shown that the rate of B. pertussis clearance following respiratory challenge of immunized mice correlated with vaccine efficacy in children. Using this model together with mice with targeted disruptions of the gamma interferon (IFN-gamma) receptor, interleukin-4 or immunoglobulin heavy-chain genes, we have demonstrated an absolute requirement for B cells or their products in bacterial clearance and a role for IFN-gamma in immunity generated by previous infection or immunization with the whole-cell pertussis vaccine. The results of passive immunization experiments suggested that protection early after immunization with acellular pertussis vaccines is mediated by antibody against multiple protective antigens. In contrast, more complete protection conferred by previous infection or immunization with whole-cell pertussis vaccines reflected the induction of Th1 cells. Our findings suggest that the mechanism of immunity against B. pertussis involves humoral and cellular immune responses which are not directed against a single protective antigen and thus provide an explanation for previous failures to define an immunological correlate of protection.

Distinct T-cell subtypes induced with whole cell and acellular pertussis vaccines in children

Recent clinical trials have demonstrated that new generation acellular pertussis vaccines can confer protection against whooping cough. However, the mechanism of protective immunity against Bordetella pertussis infection induced by vaccination remains to be defined. We have examined cellular immune responses in children immunized with a range of acellular and whole cell pertussis vaccines. Immunization of children with a potent whole-cell vaccine induced B. pertussis-specific T cells that secreted interferon-gamma (IFN-gamma), but not interleukin-5 (IL-5). In contrast, T cells from children immunized with acellular pertussis vaccines secreted IFN-gamma and/or IL-5 following stimulation with B. pertussis antigens in vitro. These observations suggest that protective immunity conferred by whole-cell vaccines, like natural immunity, is mediated by type 1 T cells, whereas the mechanism of immune protection generated with acellular vaccines may be more heterogeneous, involving T cells that secreted type 1 and type 2 cytokines.

Atypical squamous cells of undetermined significance: a comparative review of original and automated rescreen diagnosis of cervicovaginal smears with long term follow-up

BACKGROUND

There is an increasing number of articles regarding the long term follow-up of Papanicolaou (Pap) smears with the diagnosis of atypical squamous cells of undetermined significance (ASCUS). Much controversy exists regarding the management of patients with this diagnosis. In a prior study in 1992, the authors performed automated rescreening of 101 ASCUS cases and 91 negative (control) cases. They found that through PAPNET-directed rescreening, 35 of 101 ASCUS cases (35%) could be reclassified as a squamous intraepithelial lesion (SIL).

METHODS

These 192 women were followed since 1992 through manual look backs of subsequent Pap smears and surgical biopsies over a 4-year period. The population studied was comprised of predominantly black women between the ages of 14 and 85 years. The majority were considered a high risk population because many had a history of several sexual partners and multiple pregnancies.

RESULTS

Eighteen of 74 patients (24.3%) with an original diagnosis of ASCUS were found on subsequent Pap smears to have an SIL. Only 4 of 64 patients (6%) who originally had a negative Pap smear subsequently were found to have a low grade squamous intraepithelial lesion (LGSIL) within 4 years. Through ordinal logistic regression analysis, it was found that patients with an ASCUS diagnosis had a risk of developing SIL that was 2.6 times greater than the risk for patients with a negative smear diagnosis. Comparing the surgical biopsies in the control and ASCUS groups, there was no statistically significant difference in the risk of developing SIL. This may be because the number of follow-up biopsies were small.

CONCLUSIONS

A statistically significant difference of the risk of developing SIL exists between patients with a negative smear versus those with an ASCUS smear. Long term follow-up is essential in the management of the patients with an ASCUS smear because there is clearly an increased risk of developing SIL.

What precipitates deliberate self-harm? A cognitive behavioural formulation of attempted suicide presentations at an inner city hospital

OBJECTIVE

To develop a working model that provides an understanding of the process of deliberate self-harm and a framework for psychological intervention in an emergency department setting.

METHOD

A retrospective clinical audit of a consecutive series of 51 deliberate self-harm patients referred to the liaison psychiatry service by the emergency department of an inner city hospital.

RESULTS

Patient characteristics were diverse. The age range was 17-92 years, with 79% between 15 and 35 years. Most were single and unemployed and the majority had a psychiatric disorder. Characteristically, there was at least one immediate stressor and intoxication immediately before the attempt.

CONCLUSIONS

The diversity of deliberate self-harm patients requires strategic intervention in a setting such as the emergency department. The working model for intervention presented here may be transferable to other settings such as general practice or community mental health centres using an educational and skills development approach with ongoing supervision.

Spontaneous regression of granulomatous mycosis fungoides in an HIV positive patient

The development of mycosis fungoides in HIV-positive patients is uncommon. We describe the granulomatous type of mycosis fungoides in an HIV-positive patient whose cutaneous lesions regressed without treatment. In addition to HIV seropositivity and mycosis fungoides, he had a long history of pulmonary sarcoidosis. Immunophenotyping of the cutaneous lymphoid infiltrates revealed a predominance of CD4+ T cells, and monoclonality was demonstrated by T-cell gene rearrangement studies. The regression of mycosis fungoides in this patient was associated with a falling peripheral blood CD4 T-cell count.