Non-cultural detection of rectal and pharyngeal gonorrhoea by the Gen-Probe PACE 2 assay

OBJECTIVE

To assess the sensitivity and specificity of the Gen-Probe PACE 2 assay, which uses a chemiluminescent labelled single-stranded DNA probe to detect gonococcal ribosomal RNA (rRNA), for the non-cultural detection of rectal and pharyngeal gonorrhoea in homosexual men.

SUBJECTS

161 homosexual men attending the Department of Genitourinary Medicine, Edinburgh Royal Infirmary during the latter half of 1995 and the first quarter of 1996.

METHODS

Duplicate rectal and pharyngeal swabs were collected for culture on modified New York City (MNYC) medium and detection of gonococcal nucleic acid by the Gen-Probe assay. Repeatedly reactive Gen-Probe specimens from culture negative patients were also tested by the Gen-Probe competition assay (PCA).

RESULTS

Of the 161 patients, 23 (14.3%) gave a positive culture at one or both sites (rectum 10, throat 8, rectum and throat 5) compared with 28 (16.7%) who gave a positive Gen-Probe result at one or both sites (rectum 9, throat 11, rectum and throat 8). After resolution of discrepant results by PCA the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of Gen-Probe was 94.1%, 100%, 100% and 99.3% for rectal specimens while the corresponding values for pharyngeal specimens were 86.4%, 100%, 100%, and 97.9%. The sensitivity and NPV of rectal culture were 88.2% and 98.6% while the corresponding values for pharyngeal culture were 59% and 93.9%. Gen-Probe was significantly more sensitive than throat culture (p < 0.05) but not rectal culture (p > 0.2). The average Relative Light Units (RLU) value for the cut-off was 386 (range 351-450) while the average for a positive result was 20306 (range 403-110104): this was, however, significantly higher (p = 0.019) in rectal specimens 31325 (range 1705-110104) than in throat specimens 10447 (range 403-15633).

CONCLUSIONS

Gen-Probe PACE 2 assay is a sensitive and specific method for the detection of rectal and pharyngeal gonorrhoea. As the Gen-Probe assay may detect nucleic acid from non viable gonococci the clinical significance of a probe positive culture negative specimen from a patient without culture evidence of gonorrhoea at another site is uncertain and requires further consideration. Nevertheless a positive result does indicate exposure to infection and could be important in ensuring appropriate partner notification action. If non-cultural methods are used to screen for gonococcal infection cultures should be obtained from patients with positive results in order that the antibiotic susceptibility and molecular epidemiology of the gonococcal population can be monitored.

STDS in women attending family planning clinics: a case study in Addis Ababa

For cultural reasons modern contraception has been slow to gain acceptance in Ethiopia. Knowledge about contraception and abortion is still limited in many family and community settings in which it is socially disapproved. By 1990 only 4% of Ethiopian females aged 15-49 used contraception. Little is known of sexually transmitted disease (STD) prevalence in family planning (FP) attenders in Africa in general and Ethiopia in particular, even though attenders of family planning clinics (FPCs) are appropriate target groups for epidemiological studies and control programmes. A study of 2111 women of whom 542 (25.7%) attended FPCs in Addis Ababa showed utilisation rates to be highest in women who were: Tigre (33%) or Amhara (31%), aged 20-34 years (30%), age 16 or older at first marriage/coitus (28%:38% in those first married after 25 years); who had a monthly family income of 10 Ethiopian Birr (EB) or more (33%:36% for those with income 100-500 EB), three or more children (37%), more than five lifetime husbands/sexual partners (39%); or were bargirls (73%) or prostitutes (43%). The seroprevalence rates for all STDs, higher in FPC attenders compared with other women, were syphilis (TPHA) 39%, Neisseria gonorrhoeae 66%, genital chlamydia 64%, HSV-2 41%, HBV 40% and Haemophilus ducreyi 20%. Only 4% of FPC attenders had no serological evidence of STD: 64% were seropositive for 3 or more different STD. Clinical evidence of pelvic inflammatory disease (PID) was also more common in the FPC attenders (54%), 37% having evidence of salpingitis. The FPC provides a favourable setting for screening women likely to have high seroprevalence of STD, who for lack of symptoms will not attend either an STD clinic nor a hospital for routine check up. We recommend that measures be taken to adequately screen, treat and educate FPC attenders, their partners, and as appropriate and when possible their clients, in an attempt to control STDs and ultimately HIV in the community. Social, economic and cultural factors in the occurrence of STDs, prostitution, family planning and modern contraception coverage in Ethiopia are identified and deficiencies of current programmes briefly discussed with the objective of targeting services more effectively.

ECAT ART - a continuously rotating PET camera: performance characteristics, initial clinical studies, and installation considerations in a nuclear medicine department

Advances in fully three-dimensional (3D) image reconstruction techniques have permitted the development of a commercial, rotating, partial ring, fully 3D positron emission tomographic (PET) scanner, the ECAT ART. The system has less than one-half the number of bismuth germanate detectors compared with a full ring scanner with the equivalent field of view, resulting in reduced capital cost. The performance characteristics, implications for installation in a nuclear medicine department, and clinical utility of the scanner are presented in this report. The sensitivity (20 cm diameterx20 cm long cylindrical phantom, no scatter correction) is 11400 cps.kBq-1.ml-1. This compares with 5800 and 40500 cps.kBq-1.ml-1 in 2D and 3D respectively for the equivalent full ring scanner (ECAT EXACT). With an energy window of 350-650 keV the maximum noise equivalent count (NEC) rate was 27 kcps at a radioactivity concentration of approximately 15 kBq.ml-1 in the cylinder. Spatial resolution is approximately 6 mm full width at half maximum on axis degrading to just under 8 mm at a distance of 20 cm off axis. Installation and use within the nuclear medicine department does not appreciably increase background levels of radiation on gamma cameras in adjacent rooms and the dose rate to an operator in the same room is 2 microSv. h-1 for a typical fluorine-18 fluorodeoxyglucose (18F-FDG) study with an initial injected activity of 370 MBq. The scanner has been used for clinical imaging with18F-FDG for neurological and oncological applications. Its novel use for imaging iron-52 transferrin for localising erythropoietic activity demonstrates its sensitivity and resolution advantages over a conventional dual-headed gamma camera. The ECAT ART provides a viable alternative to conventional full ring PET scanners without compromising the performance required for clinical PET imaging.

Determinants of the gonococcal serovar pattern in Edinburgh, Scotland: a multivariate analysis

The geographical and temporal variety of gonococcal serovar patterns are well described but it remains uncertain what characteristics possessed by the organism, or sexual behaviour pattern in the patients, determine the particular serovar pattern in a given area at a given time. This study was designed to assess the relative contribution of various demographic and clinical features of infection to the observed pattern of serovars in Edinburgh between 1990 and 1993. Five hundred and eight isolates were included in a multivariate analysis model to control for potential interactions between variables. Associations were noted between certain serovars and an asymptomatic clinical presentation, method of acquisition and site of infection. Certain physical characteristics of Neisseria gonorrhoeae in conjunction with the sexual behaviour patterns of patients are partially responsible for observed serovar patterns but more detailed analysis requires further sub-classification of serovars using molecular techniques.

Attitudes toward use of nursing homes and home care in older Japanese-Americans

OBJECTIVE

A cohort of 1142 older Japanese Americans was identified to study preferences and attitudes regarding use of long-term care (nursing home or home care).

DESIGN

Prospective cohort study.

PARTICIPANTS AND SETTING

Older Japanese Americans in King County, Washington.

RESULTS

Subjects were asked to consider hypothetical situations in which they were temporarily disabled by hip fracture or permanently disabled by dementing illness. If they fractured a hip, only 12% intended to use a nursing home; 29% intended to recover at home with the help of family or friends; another 54% intended to use paid home health care. If they became demented, the majority (53%) intended to use a nursing home; only 11% intended to rely on family or friends for care, and another 29% intended to use paid home health care. Similar responses were observed when subjects were asked what most members of their family or friends would wish them to do; however, they tended to value the perceived wishes of religious figures or the Japanese American community-at-large less than those of family or friends. Significant correlates with intention to enter nursing homes were lack of social support (unmarried, few or no close relatives or housemates), female gender, and high levels of acculturation into American society (never lived in Japan, English-speaking only). Other factors that were not significantly correlated were health perceptions, satisfaction and life control scales, and health care utilization (hospitalizations and MD visits). In multivariate logistic regression, marital status and level of acculturation were the most powerful independent predictors of intention to enter nursing homes. Age and female gender were predictors of intention to use home care. In the base population of subjects, the prevalence of nursing homes use (5%) was similar to that of the general US older population.

CONCLUSIONS

We conclude that older Japanese Americans in the Pacific Northwest often intend to enter nursing homes if they became disabled by dementing illness. Actual use is similar to other older populations. This may be attributable largely to the existence of an ethically appropriate nursing home which is strongly supported by, and familiar to, this close-knit community. Intention to use long-term care services appears to be dependent primarily on the level of social supports and acculturation into American society.

An evaluation of pre-poured selective media for the isolation of Neisseria gonorrhoeae

Fourteen commercial media supplied as pre-poured plates were compared with an 'in-house' selective medium for their ability to support the growth of 105 gonococcal isolates (representing a wide variety of serovars encountered in natural infection), 25 meningococcal and 20 Neisseria lactamica isolates, and to inhibit the growth of 71 isolates of non-pathogenic neisseriae and miscellaneous organisms. Only two of the pre-poured plate media and the in-house selective medium yielded growth of duplicate cultures of all 105 gonococcal isolates after incubation for 24 h: one other medium provided growth of all the isolates after incubation for 48 h. The ability of the various media to suppress the growth of the 71 isolates of non-pathogenic neisseriae and miscellaneous organisms ranged from 97.2 to 71.8% of isolates inhibited. Of the four media that enabled growth of all the gonococcal strains, inhibition was 94.4% for the in-house medium, 85.9% and 80.3% for the two media on which all gonococci grew after 24 h and 71.8% for the medium on which all of the gonococci grew after 48 h. Failure of growth of gonococci was associated with: serogroup IA isolates (p<0.001), AHU auxotype (p<0.001) and the presence of vancomycin rather than lincomycin in the selective medium (p < 0.02). The use of 10% blood and a highly nutritious medium based on the original New York City (NYC) or modified New York City (MNYC) formulation were also important in supporting growth of gonococci. One of the main problems in lack of selectivity was a failure to inhibit the growth of yeasts. As effective inhibition of yeasts was obtained with other media containing the same concentration of amphotericin, failure may be due to batch variation of supplement, media preparation, or reduced shelf life of the media. None of the commercially available pre-poured media performed as well as the in-house medium despite the fact that some of the media were prepared to a very similar formula.

Noninvasive monitoring of tumor metabolism using fluorodeoxyglucose and positron emission tomography in colorectal cancer liver metastases: correlation with tumor response to fluorouracil

PURPOSE

To investigate and measure the metabolism of colorectal cancer liver metastases using 18F-fluorodeoxyglucose positron emission tomography (FDG PET), before and during the first month of chemotherapy. The findings were compared with tumor outcome conventionally assessed using changes in tumor size.

PATIENTS AND METHODS

Patients with colorectal cancer liver metastases were treated with fluorouracil (5FU) as a protracted venous infusion (300 mg/m2/d), with or without interferon-alpha 2b for two 10-week blocks separated by a 2-week break. Before and at 1 to 2 and 4 to 5 weeks on treatment, FDG PET scans were performed. Patients fasted, were injected intravenously with FDG (50 to 100 MBq), and scanned using a large-area positron camera; the image data was processed such that regions of interest could be identified. The results were expressed as a ratio of FDG uptake in the tumor and normal liver (T:L) or as a semiquantitative standardized uptake value (SUV). These measures were compared with the tumor dimensions measured on a computed tomographic (CT) scan performed at 12 weeks from commencement of chemotherapy.

RESULTS

Twenty patients were studied; however, two did not have assessable liver metastases. Objective partial responses were observed in 11 of 18 patients. A total of 27 metastatic lesions were assessable. Pretreatment T:L ratios and SUVs did not correlate with tumor response, although response was associated with lower 1- to 2-week (1.84 v 2.17; t=2.667; P < .02) and 4- to 5-week (1.36 v 2.28; t=5.02; P < .001) T:L ratios, and 4- to 5-week (3.57 v 4.95; t=2.492; P < .05) SUVs. Expressed as a percent of the baseline values of the T:L ratio, responding lesions had a greater reduction in metabolism (67% v 99%; t=7.53; P < .001). The 4- to 5-week T:L ratio was able to discriminate response from nonresponse both in a lesion-by-lesion and overall patient response assessment (sensitivity 100%; specificity 90% and 75%, respectively).

CONCLUSION

Positron emission tomography used to evaluate the uptake of FDG in tumors yields data that correlate with the antitumor effect of chemotherapy in patients with liver metastases from colorectal cancer.

Serovar specific immunity to Neisseria gonorrhoeae: does it exist?

OBJECTIVE

To determine whether the host immune response to gonorrhoea provides limited serovar specific protection from reinfection.

SUBJECTS

508 episodes of gonorrhoea diagnosed at a city centre genitourinary medicine clinic including 22 patients with multiple infections over a 4 year period.

METHODS

Patients with recurrent gonococcal infection were analysed with respect to the initial and subsequent serovars isolated.

RESULTS

No significant difference was seen in the prevalence of serovars isolated following a repeat infection compared with those without repeat infections. The site of the initial infection did not appear to influence the subsequent serovar isolated.

CONCLUSION

We found no evidence of serovar specific immunity in our population. It remains possible that populations with a higher prevalence of gonorrhoea and more frequent infections may have a quantitatively greater immune response.

Malnutrition and poverty in the early stages of famine: North Darfur, 1988-90

In this article we report findings on the relationship between malnutrition and poverty during a period of acute food insecurity in Darfur, Sudan. Children of rich and poor families were equally likely to be malnourished, which is explained in terms of people's responses to the threat of famine. This finding has important implications for targeting interventions in the early stages of famine. Appropriate interventions at the early stages of famine are livelihood and income support to the most vulnerable. The entitlement theory of famine causation assumes that the poor are most vulnerable, and become malnourished and die during famines. In this article we show that this assumption does not hold. Even though poverty is the root cause of malnutrition, it does not follow that anthropometric status can be used to target individual poor families, or even that targeting the poor is appropriate in famine situations.

Gonococcal serovar patterns in Glasgow: 1990-1992

Using monoclonal antibodies directed against protein 1 (major outer membrane protein) in the cell wall of Neisseria gonorrhoeae it is possible to serotype the gonococcus into different sub-groups. This study was designed to analyse the distribution of such serovars in Glasgow, Scotland, and report associations between serovars and clinical features of infection. N. gonorrhoeae isolated from all patients with a diagnosis of gonorrhoea attending genitourinary medicine clinics in Glasgow were serotyped between January 1990 and December 1992. The results were then correlated with sexual orientation of patients, penicillin sensitivity, site of infection, location of acquisition of infection and presence of symptoms. Six hundred and four episodes of gonococcal infection were analysed and an association between certain serovars with sexual orientation, penicillin sensitivity and asymptomatic infection was found. No association between serovar type and locality of acquisition of infection was apparent. Although there was a decreasing trend in the incidence of gonorrhoea overall, infections in homosexual men increased over the three-year study period. The associations between serovars and other features of gonococcal infection are discussed. The observed increase in homosexually-acquired infection has implications with regard to the spread of human immunodeficiency virus infection in this area, and suggests that attempts to promote safer sex in this group are failing.

Nutrition, disease and death in times of famine

In this article we review the relationship between malnutrition and mortality, and the interaction of morbidity, with the aim of clarifying the health risks of malnutrition in situations of famine and food insecurity. Apart from reviewing what is known about this relationship, we highlight areas where further research is needed. Among refugee and famine affected populations living in camps, there appears to be a close association between high rates of malnutrition and excess mortality. Results from community-based prospective studies of malnutrition and mortality among individuals conclude that as nutritional status declines the risk of death increases, although the discriminating power of different nutritional indices and the strength of the association varies considerably in different locations and at different times. These differences are attributed mainly to the different prevailing patterns of morbidity and growth failure, which are influenced by both environmental and social factors. In situations of famine and population displacement, the deterioration in the health environment increases exposure to infection and is likely to raise the threshold of nutritional status which corresponds to an increased risk of mortality. This has important implications for nutritional assessments and interventions.

Pharmacokinetics and biodistribution of radiolabelled idoxifene: prospects for the use of PET in the evaluation of a novel antioestrogen for cancer therapy

With a view to evaluating the role of PET imaging in the development of new anticancer drugs, we are investigating the novel antioestrogen pyrrolidino-4-iodotamoxifen (idoxifene). [125I]idoxifene and [131I]idoxifene have been produced in no-carrier-added form using a tributyl stannylated precursor, and the bio-distribution and dynamic behaviour of the compound investigated using syngeneic transplantable mammary tumours in the rat. Our findings support the use of PET imaging with 124I to study the clinical pharmacology of idoxifene. Factors other than hormone receptor levels appear to influence tumour uptake and therefore, possibly the biological effects of this compound.

Markers of past syphilis in HIV infection comparing Captia Syphilis G anti-treponemal IgG enzyme immunoassay with other treponemal antigen tests

The sensitivity of the Captia Syphilis G anti-treponemal IgG enzyme immunoassay (EIA-IgG) was compared with the Treponema pallidum haemagglutination assay (TPHA) and the Fluorescent Treponemal Antibody Absorbed (FTA-Abs) test as a marker for past syphilis in 28 HIV-infected and 31 HIV-negative patients with a past history of syphilis. The specificity of EIA-IgG was compared in 89 patients without a history of syphilis who were known to be HIV antibody positive with a control group of 89 patients who had tested HIV negative. In patients with a past history of syphilis each treponemal test (EIA-IgG, TPHA and FTA-Abs) gave a lower sensitivity (82%, 86%, 79%) in the HIV-positive group than in the HIV-negative group (97%) but the difference was significant only in the case of the FTA-Abs test (P < 0.05). In the HIV-positive patients 11% (3/28) were negative in all 3 treponemal tests while 25% (7/28) were negative in at least one treponemal test. In patients without a past history of syphilis the EIA-IgG antibody index in the HIV-positive group (0.436) was significantly higher than in the HIV-negative group (0.378): the specificity, however, was similar in the HIV-positive (100%) and HIV-negative group (99%). We conclude that the Captia Syphilis G anti-treponemal IgG enzyme immunoassay is of similar specificity in HIV-positive and HIV-negative patients and is of similar sensitivity to the TPHA and FTA-Abs as a marker of past syphilis in HIV-infected patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Temporal changes in the sensitivity of Neisseria gonorrhoeae to penicillin in Edinburgh, Scotland

Increased resistance of Neisseria gonorrhoeae to penicillin has been reported from many centres around the world since the introduction of antibiotic therapy in the 1940s. This study reports the temporal changes in gonococcal penicillin sensitivity over a 3-year period. All patients with a diagnosis of gonorrhoea in the city of Edinburgh, Scotland between 1990 and 1992 were included in the study. Penicillin sensitivity of isolates was analysed in relation to the sex and sexual orientation of the patient and the antibiotic therapy given. Four hundred and twenty-seven new patient episodes of infection occurred of which penicillin sensitivities were available in 426. Eleven episodes of PPNG infection occurred. Chromosomally mediated penicillin resistance did not increase over the study period. No differences were evident in the sensitivity of isolates from homosexual and heterosexual patients. Unlike many other areas the relative resistance of N. gonorrhoeae is not increasing in Edinburgh at present. This may relate to local antibiotic policies combined with intrinsic characteristics of N. gonorrhoeae itself. Unlike previous reports there did not appear to be any increased resistance to penicillin in isolates from gay men.

Nutritional assessments, food security and famine

The widely held view that malnutrition is a late indicator of famine is challenged on the basis of evidence that people often deliberately reduce their food intake as an early response to inadequate food security. This broadens the possible interventions in response to high malnutrition rates to include measures to support livelihoods under threat of collapse. In the late stages of famine, social disruption and distress migration often result in a degraded health environment which may raise the threshold of nutritional status associated with an increased mortality risk. It is important to assess the underlying causes of malnutrition and the associated health risks. At present, the main objective of nutrition surveys is usually to obtain a reliable estimate of the prevalence of malnutrition among children under five years of age, with little analysis of the underlying causes of malnutrition. Experience from the 1984-85 famine in Darfur led to the development of an alternative approach to nutritional assessment which could be applicable elsewhere in Africa. The combination of quantitative and qualitative methods was particularly valuable as a means of gaining a wider and deeper understanding of the nature of the nutritional situation.

Storage and repeated recovery of Neisseria gonorrhoeae using cryovials

One hundred gonococcal isolates, representing eight protein IA serovars and 14 protein IB serovars, were stored at -70 degrees C using the Pro-Lab Microbank cryovial storage system. At monthly intervals a bead from each cryovial was removed and cultured on modified New York City medium. The overall recovery rate was 98.6% (2365/2400), the 35 failures representing 13 separate isolates. There was a small but significant decrease in recovery in the last 12 months of the trial (97.8%) compared with the first 12 months (99.8%), which may have been due to a sampling problem rather than a temporal phenomenon. Failures were significantly associated with minor serovars, suggesting that the transmissibility/viability of minor serovars may be lower than that of common serovars and could be a significant factor in the epidemiology of gonococcal infection. We conclude that Pro-Lab Microbank cryovials provide a highly effective and convenient system for storage of Neisseria gonorrhoeae, particularly when multiple retrieval is required, and the system offers many advantages over conventional lyophilisation.

Serotonin immunoreactivity in the ventral nerve cord of the primitive crustacean Anaspides tasmaniae closely resembles that of crayfish

Syncarid crustaceans, of which only a few living species remain, have articulated segments with well-developed appendages along the length of the body, an arrangement thought to resemble that of the earliest malacostracan crustaceans. Decapod malacostracans have fused thoracic segments and reduced abdominal appendages. Modern representatives of the two groups are separated by at least 300 million years of evolutionary history. The serotonin immunoreactivity of ganglia and connectives from the ventral nerve cord of the syncarid Anaspides tasmaniae was compared with that of serially homologous ganglia of the crayfish Cherax destructor. Both species show the serotonin-immunoreactive longitudinal fibre bundles described from other decapods and thought to be part of a neuromodulatory network. They also have in common a number of the cell bodies associated with this system. Each species has some serotonergic cells in the region examined that are not present, or that do not stain, in the other species.

Gonorrhoea in Aberdeen: a serovar analysis

The serotyping of gonococcal isolates has enabled detailed studies of the epidemiology of gonorrhoea in different geographical areas. This study reports the patterns of infection found in 1992 in Aberdeen and relates these to a variety of clinical parameters. 140 cases of gonorrhoea were isolated the majority of which belonged to one strain (lA-2) in contrast to the diversity of strains seen in other Scottish cities. Most isolates were highly sensitive to penicillin and only 3 penicillinase producing strains were found. A low rate of infections in homosexual men is reported again in contrast to the situation seen in other geographically close cities. Compared to the rest of Scotland Aberdeen has a high prevalence of gonorrhoea.

Tissue blood flow estimation with copper(II)-pyruvaldehyde bis (N-4-methylthiosemicarbazone) and PET

Copper (II)-pyruvaldehyde bis (N-4-methylthiosemicarbazone) (Cu-PTSM) labelled with 62Cu or 64Cu is currently under investigation as a radiotracer for imaging the distribution of blood flow with positron emission tomography (PET). The application of a simple trapped tracer model in conjunction with tissue uptake and continuous arterial sampling to estimate blood flow has been compared with the 57Co-microsphere method in the rat. After intraventricular injection the cumulative arterial function for 64Cu increased progressively due to the presence of circulating non lipophilic complexes. The cumulative function for lipophilic 64Cu-PTSM extracted in n-octanol plateaued at levels corresponding to those reached by 57Co-microspheres. No consistent disagreement was found between cardiac output and blood flow estimated by 64Cu-PTSM and 57Co-microspheres in low to moderate flow tissues: muscle (0.08, 0.07 mL/min/g; 64Cu mean, 57Co mean), brain (0.52, 0.43 mL/min/g) and kidney (2.29, 2.45 mL/min/g). However, 64Cu-PTSM underestimated blood flow measured by 57Co-microspheres in myocardium (4.09, 6.55 mL/min/g). A simple tissue trapping model may therefore be suitable for the derivation of blood flow estimates in low to moderate flow tissues using 62,64Cu-PTSM, PET imaging and continuous arterial sampling with n-octanol extraction.