Presence of Multiple Copies of the Capsulation b Locus in InvasiveHaemophilus influenzaeType b (Hib) Strains Isolated from Children with Hib Conjugate Vaccine Failure

Most invasive Haemophilus influenzae type b strains possess a duplication of the capsulation locus. Further amplification resulting in as many as 5 copies has been described. To verify whether amplification is involved in vaccine failure, the number of copies of the locus was determined by Southern blotting in 90 strains from children with true vaccine failure (TVF) between 1993 and 1999 and in 139 strains from unvaccinated children (50 collected between 1993 and 1999 and 89 collected between 1991 and 1992, before routine immunization was introduced). A significantly greater proportion of strains from TVFs contained multiple copies, compared with strains from control children (24% vs. 10%; P = .0379), which suggests that amplification of the capb locus may be a contributory factor in vaccine failure. The presence of multiple-copy strains was associated with disease other than meningitis.

In vivo comparison of suburethral sling materials

In vivo tissue responses were compared for three commercially available polypropylene suburethral slings that differ markedly in fabric structure and in size of resulting interstices and pores. All three elicited the same basic inflammatory response; however, individual fabric structures produced distinct differences in tissue formation within each mesh. The presence of numerous, closely spaced, small diameter filaments prevented formation of extensive fibrous connective tissue within two slings (ObTape and IVS Tunneller mesh). The much larger diameter monofilament and open knit structure of the Monarc sling permitted the most extensive fibrous tissue integration. These differences may be of interest to physicians considering clinical use.

Urethral retro-resistance pressure: A new clinical measure of urethral function

AIMS

The urethral retro-resistance pressure (URP) is a new retrograde measurement of urethral function. URP is the pressure required to achieve and maintain an open sphincter. The assessment of any potential diagnostic measure must include an evaluation in individuals both with and without disease. In this study, we examined URP values in women without urinary incontinence.

METHODS

Four centers enrolled 61 women who did not report symptoms of urinary incontinence, and who had negative standing stress tests (SST). Each center was to perform three consecutive URP measurements on each subject. At two centers, 32 subjects returned in 3-7 days for three additional URP measurements. We compared the average URP in this asymptomatic population to the average URP from women symptomatic of stress urinary incontinence (SUI) derived from a previous study. We evaluated the within-subject variation of the URP measurement at a single visit and the within-subject change in URP over time using test and retest values.

RESULTS

The mean age was 33 +/- 9 years and the mean body mass index (BMI) was 24 +/- 6. URP values were normally distributed. The mean URP at visit 1 was 112.6 +/- 39.2 cm H2O (n = 60). This was statistically significantly different from the mean URP of symptomatic women (69.9 cm H2O, P < 0.0001). The within-subject standard deviation of URP at visit 1 was 12.6 +/- 12.6 cm H2O (n = 60) and at retest visit was 9.3 +/- 6.2 cm H2O (n = 32). For the retest cases, the mean URP at visit 1 was 113.9 +/- 39.9 cm H2O (n = 32) and at retest visit was 125.5 +/- 33.9 cm H2O (n = 32) (Wilcoxon Signed Rank test, P = 0.145).

CONCLUSIONS

The mean URP measurement obtained in this study of asymptomatic women showed significantly higher values when compared to our study in women with SUI. The URP measurements were consistent within the same subject. Furthermore, there was no statistically significant difference in the URP measurement from visit 1 to retest visit. The data suggest that URP shows promise as a physiological urethral pressure measurement.

Outbreak of Haemophilus influenzae type b disease among fully vaccinated children in a day-care center

BACKGROUND

Two cases of invasive Haemophilus influenzae type b (Hib) infection were reported in immunized children in a day nursery within 1 week. Both cases were younger than 18 months of age, cared for in the same room. We aimed to characterize carriage of Hib and response to eradication therapy in this setting.

METHODS

Ninety-four children were enrolled in the nursery, cared for by 21 staff in 4 rooms, divided by age. Two children of a part time teacher also attended. Oropharyngeal swabs were taken to detect Hib carriage before introduction of rifampin prophylaxis (20 mg/kg/day for 4 days). A questionnaire addressing risk factors for colonization was administered to parents and staff. Carriage was reassessed in children and carers from the same room as the index cases 1 month later.

RESULTS

Eighty-nine children and all 21 staff were swabbed. Two additional Hib carriers, 1 child and 1 staff member, were identified from the same room as the cases. These isolates appeared identical with those causing invasive disease. Given the small numbers no clear risk factors for carriage could be confirmed. Compliance with rifampin prophylaxis was 97.4%. One month later no carriers were found among the 7 children and 3 staff tested from the room in which the cases were originally identified.

CONCLUSIONS

Although immunization against Hib has resulted in a reduction in the incidence of this disease in the UK, individual protection cannot be assumed to be infallible. The importance of timely chemoprophylaxis of close contacts of a child with invasive Hib disease is reinforced.

Relationship of urethral retro-resistance pressure to urodynamic measurements and incontinence severity

AIMS

The urethral retro-resistance pressure (URP) is a retrograde urethral pressure profile measured by a new urodynamic measurement system.1GYNECARE MoniTorr Urodynamic Measurement System (ETHICON, Inc., Somerville, NJ). URP is the pressure required to achieve and maintain an open sphincter. This clinical investigation focused on a comparison of URP to standard urodynamic measurements and an examination of their relationship to incontinence severity.

METHODS

Twenty-two centers enrolled 258 stress incontinent women in a randomized, crossover study of two groups: (1) test procedure followed by multichannel urodynamics, (2) multichannel urodynamics followed by test procedure. We defined incontinence severity categories using 24 hr urine loss and assessed these categories using incontinence quality of life (I-QOL), urinary incontinence severity score (UISS), incontinence visual analogue score (VAS), URP, maximum urethral closure pressure (MUCP), and leak point pressure (LPP).

RESULTS

The mean age was 56.2 (+/-12) years. No order effect was present. The correlation coefficient between URP and MUCP was 0.31 (95% CI 0.19-1, P < 0.0001); between URP and LPP was 0.28 (95% CI 0.12-1, P = 0.003); and between MUCP and LPP was 0.14 (95% CI-0.04-1, P = 0.101). The mean values for URP across symptom severity categories were significantly different (P = 0.028) and decreased with increasing severity. The mean values for MUCP and LPP did not decrease with increasing severity.

CONCLUSIONS

The study demonstrated that URP had a consistent relationship with incontinence severity. The data suggested that URP is a physiological measure of urethral function and may have clinical utility as a diagnostic tool. Future outcomes-based research is necessary to establish the predictive value of URP, MUCP, and LPP measurements in terms of incontinence cure rates and diagnosis of sphincter dysfunction.

A study of hormone replacement therapy in postmenopausal women with ischaemic heart disease: the Papworth HRT Atherosclerosis Study

OBJECTIVE

To assess the possible benefit of hormone replacement therapy (HRT) in the secondary prevention of ischaemic heart disease.

DESIGN

A prospective randomised trial of transdermal HRT in women with definite ischaemic heart disease.

SETTING

A regional cardiac unit.

POPULATION

Postmenopausal women with angiographically proven ischaemic heart disease.

METHODS

A total of 255 postmenopausal women with angiographically proven ischaemic heart disease were recruited and randomised; 134 were treated with transdermal HRT and 121 acted as controls. The women were seen at six monthly intervals. The primary end points, which were determined by a blinded assessor, were admission to hospital with unstable angina, proven myocardial infarction or cardiac death. A total of 53 (40%) patients withdrew from the HRT group and eight (7%) from the control group. The mean duration of follow up was 30.8 months.

MAIN OUTCOME MEASURES

Admission to hospital with unstable angina, proven myocardial infarction or cardiac death.

RESULTS

During follow up, there were 53 primary end-point events in the HRT group and 37 in the control group. Using an intention-to-treat analysis, the primary end-point event rate was 15.4 events per 100 patient years for the HRT group compared with 11.9 for the control group (event rate ratio 1.29 (95% CI 0.84-1.95, P = 0.24)). Using a per-protocol analysis, there was an event rate ratio of 1.49 (0.93-2.36, P = 0.11) for the HRT arm compared with the control arm. Particularly during the first two years of follow up, the HRT group had a higher, but not statistically significant, event rate than the control group.

CONCLUSION

Our findings suggest that transdermal HRT should not be commenced for the purpose of secondary prevention in postmenopausal women with angiographically proven ischaemic heart disease.

Haemophilus influenzae type b and cross-reactive antigens in natural Hib infection dynamics; modelling in two populations

Natural immunity to Haemophilus influenzae type b (Hib) invasive disease is based on antibodies arising in response to encounters with Hib or cross-reactive (CR) bacteria. The relative importance of Hib and CR contacts is unknown. We applied a statistical model to estimate the total rate of immunizing infections of Hib and CR prior to wide-scale vaccinations in Finland and the UK. The average rates of these contacts were 0.7 and 1.2 per year per child in Finland and the UK, respectively. Using a rough estimate of 0.1 Hib acquisitions per year per child in the UK based on carriage rates, the proportion of Hib among all immunizing contacts was in the order of 10%, suggesting that CR bacteria have a major role. In general, varying frequency of CR contacts may explain some differences in the pre-vaccination incidence and age-distribution of invasive disease in different countries.

Analyses of spontaneous mutations of cloned gene 49 of phage T4

Holliday structure resolving enzyme endonuclease VII (endo VII) of phage T4 is highly toxic for E. coli when expressed outside of the phage infection environment. As a consequence, plasmids with a mutated gene 49, the gene which encodes for endo VII, can be easily isolated and characterised. We have isolated and characterised 400 survivors from independent transformations with a plasmid carrying gene 49 under the control of the T7 promoter. The majority had mutated gene 49 by IS10 insertions which almost exclusively mapped to a distinct site. When this site was mutated other insertion sites were observed as well as an increase in other mutational events including large deletions. Neither of the observed insertion sites mapped matched the consensus IS10 sequence completely. Additionally when the level of expression of gene 49 was altered the distribution of mutations was changed suggesting that other elements apart from the target sequence are necessary for determining IS10 insertion. The expression of gene 49 in E. coli provides a particularly useful tool for the analysis of mutational events.

Invasive Haemophilus influenzae disease in adults

We reviewed retrospectively all invasive Haemophilus influenzae (Hi) infections in adults ascertained from reference laboratory records and notifications from five NHS regions over the 5 years from 1 October 1990, a period encompassing the introduction of routine Hib childhood immunization (October 1992). A total of 446 cases were identified, a rate of 0.73 infections per 10(5) adults per annum. Though numbers of Hib infections in adults fell after the introduction of Hib vaccines for children (P = 0.035), and there was no increase in infections caused by other capsulated Hi serotypes, total numbers of invasive Hi infections increased due to a large rise in infections caused by non-capsulated Hi (ncHi) strains (P = 0.0067). There was an unexpectedly low rate of infections in those aged 75 years or more (P < 0.0001). The commonest clinical presentations were pneumonia with bacteraemia (227/350, 65%) and bacteraemia alone (62/350, 18%) and the highest rates of disease were in the 65-74 years age group (P < 0.0001). Clinical presentation was not influenced by the capsulation status of the invading Hi strain. 103/350 cases (29%) died within 1 month, and 207/350 (59%) within 6 months of their Hi infection. Case fatality rates were high in all age groups. Pre-existing diseases were noted in 220/350 cases and were associated with a higher case fatality rate (82% vs. 21%, P < 0.0001). After the introduction of Hib immunization in children, invasive Hib infections in unimmunized adults also declined, but the overall rate of invasive Hi disease in adults increased, with most infections now caused by non-capsulated strains. Physicians and microbiologists should be aware of the changing epidemiology, the high associated mortality and high risk of underlying disease. Invasive haemophilus infections in adults should be investigated and treated aggressively.

Functional coexpression of HSV-1 thymidine kinase and green fluorescent protein: implications for noninvasive imaging of transgene expression

Current gene therapy technology is limited by the paucity of methodology for determining the location and magnitude of therapeutic transgene expression in vivo. We describe and validate a paradigm for monitoring therapeutic transgene expression by noninvasive imaging of the herpes simplex virus type 1 thymidine kinase (HSV-1-tk) marker gene expression. To test proportional coexpression of therapeutic and marker genes, a model fusion gene comprising green fluorescent protein (gfp) and HSV-1-tk genes was generated (tkgfp gene) and assessed for the functional coexpression of the gene product, TKGFP fusion protein, in rat 9L gliosarcoma, RG2 glioma, and W256 carcinoma cells. Analysis of the TKGFP protein demonstrated that it can serve as a therapeutic gene by rendering tkgfp transduced cells sensitive to ganciclovir or as a screening marker useful for identifying transduced cells by fluorescence microscopy or fluorescence-activated cell sorting (FACS). TK and GFP activities in the TKGFP fusion protein were similar to corresponding wild-type proteins and accumulation of the HSV-1-tk-specific radiolabeled substrate, 2'-fluoro-2'-deoxy-1beta-D-arabinofuranosyl-5-iodo-uracil (FIAU), in stability transduced clones correlated with gfp-fluorescence intensity over a wide range of expression levels. The tkgfp fusion gene itself may be useful in developing novel cancer gene therapy approaches. Valuable information about the efficiency of gene transfer and expression could be obtained by non-invasive imaging of tkgfp expression with FIAU and clinical imaging devices (gamma camera, positron-emission tomography [PET], single photon emission computed tomography [SPECT]), and/or direct visualization of gfp expression in situ by fluorescence microscopy or endoscopy.

An assessment of registrars and their training programmes at the University of Cape Town Teaching Hospitals

In order to describe the registrar population and to highlight their problems, a study using an anonymous questionnaire was conducted in August 1988 at the University of Cape Town Group of Teaching Hospitals. The average age of respondents was 32 years and the majority had family responsibilities (60% married, 41% with dependents). They had significant medical experience and postgraduate qualifications. Registrars work long hours (mean 66 +/- 13.7 h/wk), with duty shifts that can extend for up to 34 hours. Most of their time at work was devoted to patient care, with time for study and research virtually non-existent. Although the majority (61%) felt that the 'registrar experience' was worthwhile, a significant proportion of respondents (45%) had considered leaving the rotation. The study revealed several shortcomings that need to be addressed if candidates of good calibre are to be attracted, academic standards are to be maintained and sufficient specialists produced to serve the needs of our population adequately.

Effect of information organization on recall of medication instructions

This study compared immediate recall of prescription information when the message content was presented in a highly organized format versus a less-organized approach. Two groups of pharmacy students viewed separate videotapes, which described information for a patient about three fictitious medications. Students were then asked to recall the medications' name, colour, purpose, dosage, duration, side-effects and quantity prescribed. Students who viewed the organized version correctly recalled more information in every category except drug colour. Both groups made more errors in recalling dosage than any other category. Thus, organizing information facilitates recall of medication information.

The effect of trimethoprim-polymyxin B sulphate ophthalmic ointment and chloramphenicol ophthalmic ointment on the bacterial flora of the eye when administered to the operated and unoperated eyes of patients undergoing cataract surgery

Both eyes of patients undergoing cataract surgery were treated with an ointment preparation containing either trimethoprim 5 mg/g and polymyxin B sulphate 10,000 units/g, or chloramphenicol 1%. The antibiotic preparations were administered four times daily on the day prior to surgery, once in the morning prior to surgery and twice daily for fourteen days post-operatively. Cultures from conjunctivae and lid margins were taken prior to treatment, pre-operatively and post-operatively on selected days including the fourteenth post-operative day. The effect of the antibiotics on conjunctival and lid margin flora was determined by enumerating patients with positive cultures prior to treatment which were eradicated following treatment and patients with organisms which were cultured de novo in spite of antibiotic treatment. There was no significant change in the number of patients with organisms isolated from conjunctivae and lid margins (p greater than 0.1 in each case, Sign test) over the sixteen day study period with either treatment. Additionally, when the effect of the two preparations on the number of patients with organisms obtained from conjunctivae and lid margins was compared, there was no significant difference between them (p greater than 0.1 conjunctival cultures, p greater than 0.1 lid margin cultures, Fisher's Exact probability test).

Trichosporon capitatum causing recurrent fungal endocarditis

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Multiplication of contaminant bacteria in urine and interpretation of delayed culture

A prospective study of the bacterial populations of non-infected urine was mounted in an attempt to define the length of delay between voiding and analysis during which culture would not give false positive results due to the multiplication of contaminant bacteria present at the time of voiding. The findings suggest that culture of urine within four hours of voiding is likely to give a true indication of the presence or absence of infection. With further delay the interpretation of a heavy growth of bacteria in urine becomes progressively more unreliable, even if that growth is in pure culture.