Hepatitis B surface antigen detection using pooled sera. A cost-benefit analysis

OBJECTIVES

To examine the feasibility and to perform a cost benefit analysis of a 5-sample pooling strategy using an enzyme immunoassay (EIA) for the screening of hepatitis B surface antigen (HBsAg).

MATERIAL AND METHODS

To assess the sensitivity and specificity of the pooling method, each of the 40 positive sera (from weak to intensely HBsAg-positive) and 250 negative sera were tested in a pool with 4 HBsAg-negative sera. The limit of detection for HBsAg/ad and HBsAg/ay was evaluated using sera from a panel of purified subtypes. A study under real conditions was conducted using pools from 340 pregnant women.

RESULTS

The sensitivity and specificity of this technique were 100%. The correlation coefficient among the sample/cutoff ratios of 40 samples studied in single and in pooled conditions was 0.792 (p < 0.005). The pooling method has lower levels of detection for HBsAg/ad and HBsAg/ay at 0.20 ng/mL and 0.12 ng/mL, and the single method at 0.34 ng/mL and 0.29 ng/mL, respectively. The pooling method loses no sensitivity for values up to 100 IU/L of anti-HBs in the four sera mixed with a positive serum. The cost-benefit analysis showed that the pooling method could save from 30% up to 75% of the cost of HBsAg determination, according to whether seroprevalences were 10% or 1%, respectively.

CONCLUSIONS

The pooled HBsAg EIA yielded no worse than the single EIA test, and was a cost-effective and valid strategy in areas with a high, medium or low prevalence.

Role of apolipoprotein E epsilon 4 allele on chronic allograft nephropathy after renal transplantation

Lipid abnormalities may contribute to chronic allograft nephropathy (CAN). Apolipoprotein E (ApoE) gene polymorphism regulates lipoprotein metabolism, but little is known about an association between CAN and this polymorphism. The ApoE gene (E3/E4) polymorphism was typed by PCR assay (99 E3/E3, 28 E3/E4, 1 E4/E4) on 128 consecutive renal transplant patients with functioning grafts for more than 3 years (6.7 +/- 2.8 years). Twenty-eight patients with histological CAN were compared with 100 patients who had no clinical evidence of chronic rejection (no proteinuria and sCr < 2.5 mg%). As expected, univariate analysis revealed that patients with CAN experienced a greater acute rejection rate (78% vs 21%; P=.001), a higher serum creatinine (3.6 +/- 1.7 vs 1.4 +/- 0.5 mg%; P=.0001), and an older organ donor (43 +/- 20 vs 29 +/- 13 years; P=.0001). The lipid profiles (total cholesterol and triglycerides levels) were similar in both groups with 60% in each group receiving anti-lipemic drugs. Interestingly, the ApoE epsilon 4 allele was overrepresented in the group with CAN (39% vs 17%, P=.019). Logistic regression analysis showed that the epsilon 4 allele was an independent predictor of CAN (OR: 3.4; CI 95%: 1.07 to 11; P=.040) as were donor age and acute rejection episodes. In conclusion, an interaction between risk factors and genetic factors may determine CAN in this population. This finding may help to target prophylactic interventions in these recipients.

[Carcinoid tumor and bone metastases: diagnosis by somatostatin receptor scintigraphy]

OBJECTIVE

The aim of this study has been to retrospectively assess the usefulness of 111In-DTPAOC scintigraphy in the detection of bone metastases (BM) in patients diagnosed of carcinoid tumour (CaT).

MATERIALS AND METHODS

Between June 1995 and April 2003 78 111In-DTPAOC studies were consecutively performed in 58 patients, 31 females and 27 males, 28 to 73 years old, with a histological diagnosis of CaT. Moreover, whole body bone scans (BS) using 99mTc-MDP were performed in 13 of these patients. The patients were classified into three groups: Group A: Initial CaT staging (n = 23); Group B: CaT staging after surgery (n = 14); and Group C: Post-treatment CaT re-staging (n = 29). In this last group, 6 patients of group A and 2 patients of group B were included. In only 2 patients the diagnoses of bone metastases were established before the 111In-DTPAOC scan.

RESULTS

Twenty six (44.8 %9 of the 58 patients with CaT had metastatic disease: 15 patients with hepatic metastases, associated with BM in 4 of them, 10 patients with hepatic and extra-hepatic metastases, abdominal and/or thoracic, associated with BM in 4 and in one patient, the BMs were the only metastases detected. The global incidence of BM in patients diagnosed with CaT was 15.5 % (9/58), whereas the incidence of BM in patients with metastasic disease was 34.6 % (9/26). Significant differences (p = 0.0035) were found on the incidence of BM in patients with or without hepatic metastases. In 4 patients, BMs were detected during the initial staging (group A), whereas in 5 patients, BMs were detected during the post-treatment re-staging (group C). During diagnosis, 4 of the 9 patients with BM had bone pain. BM were multiples in 8 patients, affecting axial skeleton in 4 and axial and appendicular skeleton in 4. One patient had a diffuse infiltration of bone marrow. BS was positive in 8 of the 9 patients with BM. In these 8 patients with abnormal BS, 111In-DTPAOC scintigraphy provides similar information to the BS in one patient, shows a greater number of bone lesions in 3, whereas BS was superior in 5 patients. Four of the patients with BM died between 6 and 47 months after diagnosis (mean: 29.7 months).

CONCLUSIONS

BMs are preferably located on axial skeleton, can be asymptomatic and are associated with hepatic metastases. Although the 111In-DTPAOC scintigraphy is able to detect some BM earlier than BS, the information provided by both studies is complementary. In patients with CaT, any invasive therapy on the hepatic metastases make it necessary to exclude extrahepatic metastases, including bone ones, and the somatostatin receptor scintigraphy is the diagnostic method of choice.

Plasma RNA viral load is not associated with intrapatient quasispecies heterogeneity in HIV-1 infection

The human immunodeficiency virus type 1 (HIV-1) viral set point has been associated with the rate of, disease progression and with the level of HIV-specific immune response. The analysis of the possible association between viral set point and quasispecies heterogeneity has important consequences in the understanding of HIV-1 in vivo evolution. In this study, we analyzed the association between intrapatient viral diversity and RNA viral load in 16 antiretroviral therapy-naive HIV-1-infected patients at a single time point, during the disease free period. Patients were separated into low and high viral load groups according to plasma RNA values. HIV-1 quasispecies complexity was assessed in the C2-V5 env region. The average intrapatient quasispecies heterogeneity in both groups was not significantly different (t-test, P > 0.05). However, while within the low viral load group both synonymous and non-synonymous mutations contribute to the variation observed, in the heterogeneity observed in the high viral load group there was an increase in the contribution of the non-synonymous mutations. Thus, this study show that although intrapatient quasispecies heterogeneity is not associated with viral set point in HIV-1 infection, some differences exist between the two groups in the pattern of mutation accumulation.

The Fang population of Equatorial Guinea characterised by 15 STR-PCR polymorphisms

Allele frequencies for 15 STR loci (D8S1179, D21S11, D7S820, CSF1PO, D19S433, HUMVWA31A, HUMTPOX, D18S51, D3S1358, HUMTHO1, D13S317, D16S539, D2S1338, D5S818 and HUMFGA) were analysed in the Fang population of Bioko Island, Equatorial Guinea. No deviation from Hardy-Weinberg equilibrium was found for all loci. Statistical parameters demonstrated the forensic utility of the analysed systems.

[Women who are partners of a man infected by HIV: description of their characteristics and appraisal of risk]

OBJECTIVE

To describe the situations of risk and the prevalence of HIV in women with a heterosexual partner infected by HIV.

DESIGN

Cross-sectional descriptive study.

SETTING

Out-patient HIV diagnosis centre in Madrid.

PATIENTS

229 women seen for the first time between 1993 and 2002 because they had a stable heterosexual partner diagnosed with HIV, and who were exposed to no other risk.

MAIN MEASUREMENTS

Social and personal details, reproduction history, sexual conduct, clinical, and analytic data of both partners.

RESULTS

66% of couples had maintained sexual relations for over a year. Women were on average younger (29.6 years old) than the men. 29% of the women had children and 5.2% were pregnant. 82% of men had injected drugs, but only 13% still did. 73% had been diagnosed with HIV for over 6 months, 16% had AIDS criteria, and 35% were taking retroviral treatment. 60% of the men who knew of their infection had systematically avoided sex without condoms, against 33% of those who did not know they were infected (P<.001). 19% had had accidents in use of the condom. HIV seroprevalence in the women was 6.1% (95% CI, 3.5%-10.3%).

CONCLUSIONS

Health care of people with HIV must include care of their sexual partner, involving information, psychological support, preventive and reproductive advice, as well as diagnosis of HIV or other sexually transmitted diseases.

Allograft reconstruction of the distal humerus after resection of a breast solitary metastasis: eleven years follow-up

Resection is a rare indication for the treatment of solitary skeletal metastasis (SSM), and provides an opportunity to cure the oncologic patient. Reconstruction after resection can imply a difficult problem depending on the size and the location of the metastasis. In the reported case, an en-bloc resection of a SSM of a breast cancer located in the distal humerus was performed in 1990. Reconstruction of the osteoarticular defect has been achieved with a massive allograft. At eleven years follow-up the patient remains free of illness and shows a good functional result. With the result obtained in the reported case, we suggest that osteoarticular allograft can be of considerable value for reconstruction after excision of SSM in the distal humerus, and that cure can be achieved with the radical resection of a SSM of breast cancer.

Utilidad de la detección del ganglio centinela en el tratamiento y la estadificación del carcinoma de cérvix uterino inicial

OBJECTIVE

The aim of this study was to evaluate the usefulness of intraoperative sentinel node (SN) detection in patients with initial cervix cancer.

PATIENTS AND METHODS

Lymphoscintigraphy and intraoperative SN detection was performed in 17 patients with initial cervix cancer who we going to have a radical laparoscopic hysterectomy and pelvic lymphadenectomy. Conization was performed in 4/17. The day before surgery, an injection of 111 MBq 99mtechnetium nanocolloid around the primary tumour and a subsequent lymphoscintigraphy were carried out. Blue dye was injected at the same location intraoperatively. A laparoscopic gamma probe was used to identify SNs.

RESULTS

SNs were successfully localized using a combination of radiocolloid and blue dye in 16/17 patients (detection rate 94 %). The detection rate only using blue dye technique decreases to 71 % (12/17) and it reaches an 82 % (14/17) if we avoid the blue dye injection. In 3 cases, there was no migration in lymphoscintigraphy and in one of the three SN could not be detected. Thirty-three SNs were identified (1.9 nodes/patient). The most frequent location was left external iliac nodal group (13 nodes: 39 %). SNs were identified in regions that are not included in usual lymphadenectomy: right parametrium (2 sentinel nodes, one of them in the retrouterine region), and interiliac (2 SNs). In all four patients with previous conization SNs were identified (detection rate 100 %).

CONCLUSIONS

The rate of SN detection combining lymphoscintigraphy with gamma probe and blue dye is 82 %. The use of blue dye allows increasing this rate to 94 % in those cases which migration was not seen or when the SN is placed near the injection site. The SN technique offers the possibility to find SNs in regions not included in usual lymphadenectomy.

[Bone metabolism alterations after kidney transplantation]

Early after renal transplantation (RT) a rapid decrease in bone mineral density at the lumbar spine, femoral neck, and femoral shaft has been documented. In addition, an appreciable proportion of patients still remain losing bone late after RT. As a consequence, RT patients are at a high risk of bone fractures as compared to general population. Most fractures involve appendicular skeleton, particularly the feet and ankles, and the diabetic patient is at increased risk of fractures. Thus, early institution of preventive measures and treatment of established osteoporosis are central. The major cause of post-transplantation bone loss is corticosteroid treatment, and this should be used at the lower dose compatible with graft survival. Preexisting hyperparathyroidism also affects the early cancellous bone loss at the spine, and post-transplantation bone loss reflects variable individual susceptibility, resembling the polygenic determination of bone mineral density in general. Clinical trials have demonstrated that bisphosphonates or vitamin D plus calcium supplementation, prevent post-transplantation bone loss during the first 6-12 months. However, their role in preventing bone fractures has not been proven. Finally, recommendations for management, prevention and treatment, are summarized.

Diagnosis and treatment of presumed STIs at Mexican pharmacies: survey results from a random sample of Mexico City pharmacy attendants

OBJECTIVES

People in developing countries often seek medical advice for common ailments from pharmacies. As one example, pharmacists routinely diagnose and treat symptomatic sexually transmitted infections (STIs). We aimed to assess the quality of advice provided in Mexico City pharmacies by presenting hypothetical STI related syndromes and recording pharmacy attendants' suggested diagnoses and treatments.

METHODS

We interviewed the first available attendant in each of a 5% random sample of Mexico City's pharmacies. We inquired about the training, age, and experience of the attendant and about the typical number of clients coming for treatment of suspected STIs. After considering three hypothetical case studies, attendants recommended diagnoses, treatments, and, sometimes, physician follow up.

RESULTS

Most Mexico City "pharmacists" are actually clerks, with trained pharmacists rarely available on the premises. The average pharmacy attendant was 32 years old, with a median of 5 years' experience at that pharmacy, but very limited (if any) training. 62% reported seeing 10 or more clients with genital or vaginal infections per month. Depending on the case study, attendants provided appropriate diagnoses in 0-12% of cases, recommended appropriate treatments in 12-16% of cases, and suggested physician follow up for 26-67% of cases.

CONCLUSIONS

In general, surveyed pharmacy personnel were unable to diagnose accurately or offer appropriate treatment advice when presented with classic, common STI symptoms. Given the volume of clients seeking advice from this source, training pharmacy attendants could significantly help to reduce the burden of disease associated with STIs in Mexico City.

Presumptive infection of a total hip prosthesis by Mycobacterium tuberculosis: a case report

Infection of a total hip prosthesis by Mycobacterium tuberculosis (MT) is an uncommon complication. We report a patient with septic loosening of a total hip prosthesis with a presumptive diagnosis of MT infection. His previous history was negative to any form of tuberculosis, and there was no evidence of a primary focus on the radiological study of the chest. He was diagnosed initially as presenting aseptic loosening and revision surgery was performed. Six months after surgery, septic loosening was diagnosed. The prosthesis was then removed. The histological study showed caseum granulomas and acid-fast bacilli, and routine cultures of the synovial fluid were negative. Since only a positive Löwenstein culture would have confirmed the diagnosis with certainty, a presumptive diagnosis of MR infection was made based on the findings in the histological study. Tuberculostatic treatment was administered for 9 months. At six years follow-up no signs of infection are present, neither by clinical or radiological criteria.

Absence of hepatitis C virus transmission in a prospective cohort of heterosexual serodiscordant couples

OBJECTIVE

To analyse hepatitis C virus (HCV) transmission in a cohort of heterosexual couples who are discordant both for HIV and for HCV.

METHODS

We followed an open cohort of 171 people, 152 women and 19 men, who were not initially infected by either HIV or HCV, and whose steady heterosexual partner presented antibodies to both viruses (index case). Other risk exposures were excluded. Every 6 months clinical, epidemiological, and risk behaviour information was collected, and antibodies to both viruses were determined.

RESULTS

During 529 person years of follow up more than 40 000 vaginal or anal penetrations were recorded. 74 partners (43.3%) had vaginal and/or anal intercourse without condoms with the index case; another 15.8%, who always used condoms, declared breaking or slipping episodes during intercourse; and another 22.2% had unprotected orogenital exposures. During the follow up, over 5800 unprotected vaginal and anal contacts with the index case were estimated, as well as more than 25 000 unprotected orogenital contacts. 31 women became pregnant (two were index cases), and seroconversion to HIV occurred for one woman (1.7 per 10 000 unprotected contacts; 95% CI, 0 to 9.5), but there was no seroconversion to HCV (95% CI, 0-6.3 per 10 000 unprotected contacts).

CONCLUSION

These results are consistent with a low or null transmissibility of HCV in heterosexual relations, even when the index case is HIV co-infected.

[Somatostatin receptor scintigraphy. When would a SPECT study be performed?]

Somatostatin receptor scintigraphy has become an essential tool in the treatment planning of patients with carcinoid tumor (CaT) and pancreatic neuroendocrine tumors (PNET). However, the contribution of SPECT images in the diagnosis and staging of these tumors has not been well established.

OBJECTIVE

1) To find out if SPECT improves the sensitivity of planar imaging and adds any value to tumor diagnosis, and 2) To determine under which circumstances SPECT images must be obtained.

MATERIAL AND METHODS

We have evaluated 49 patients, 26 females and 23 males, using both planar and SPECT 111In-DTPAOC images. The patients were classified into three groups according to their clinical indication: Group A: Indolent symptoms of CaT or PNET (n = 9); Group B: Known or functioning CaT or PNET tumors (n = 22); Group C: Post-surgical follow-up (n = 18). The total number of SPECT studies were 51 (37 abdomen, 13 thorax and 1 brain). In all cases SPECT was performed 24 hours after 111In-DTPAOC injection. Scintigraphic images were compared with surgical findings in 17 patients and with a synthesis of biochemical, clinical and CT findings in the other patients.

RESULTS

16 primary lesions were detected with planar images whereas SPECT detected 18. The two tumors detected only by SPECT were a bronchial CaT and an insulinoma located in the pancreatic tail. Planar and SPECT image sensitivities were 66.6% and 75% respectively. Twenty one patients developed metastatic disease. Sensitivities of planar and SPECT images for metastases were 76.1% and 90.4% respectively. Furthermore, SPECT helps planar images in the evaluation of six patients with uncertain images (lesions with low receptor density or with an uncertain scintigraphic localization). Therefore, in 15.6% of patients with primary or metastatic tumors, planar images were normal whereas SPECT was abnormal and SPECT provided an added value in 21.8% of the studies with abnormal planar images.

CONCLUSIONS

We recommend the use of SPECT images in: 1) Patients with specific functional clinical syndrome or with a known CaT or PNET and normal planar images. 2) When planar images are abnormal only in primary tumor. 3) In order to confirm the absence of other metastases in patients with known liver metastases. 4) In order to enhance the detection of lesions with low receptor density and uncertain planar images and 5) In order to determine exactly the anatomic location of some lesions

Textile dyeing wastewater treatment in a sequencing batch reactor system

This study was undertaken to examine the feasibility of treating biologically textile wastewater for organic carbon removal. The study was conducted over a lab scale SBR equipped with an in-house developed data acquisition and control software. From monitored operation of SBR and dissolved oxygen values, together with a simple compressed air ON/OFF control scheme, on-line Oxygen Uptake Rate (OUR) profiles during aerobic reaction periods were obtained. Due to the high variability of wastewater characteristics, periodical analyses of textile wastewater were conducted and thus characterized for pH, conductivity, total and volatile solids, COD, ammonia, and TKN. After an initial period of activated sludge adaptation to textile wastewater, the SBR was operated at step-feed strategy to reduce the effluent biodegradable matter presents in the wastewater by SBR water change ratio modification and feeding strategy.

[HIV prevalence among homosexual and bisexual men in Spain, 1992-2000]

BACKGROUND

Our purpose was to describe the time trend in HIV seroprevalence among homo/ bisexual men.

SUBJECTS AND METHOD

We analyzed 9,383 homo/ bisexual men who had a first voluntary test for HIV in 10 Spanish clinics from 1992 to 2000.

RESULTS

HIV prevalence decreased from 20.3% in 1992 to 8.4% in 2000. In the multivariate analysis this decline appeared independently associated with the testing year and the birth cohort.

CONCLUSIONS

New generations of voluntarily tested homo/bisexual men are less infected by HIV, but it is yet necessary to intensify the prevention programs.

[Diffusion-weighted magnetic resonance in deep cerebral venous thrombosis]

Changes in the apparent diffusion coefficient (ADC) are well established in acute ischemic stroke of arterial origin. However, ADC behaviour and its prognostic significance in cerebral venous thrombosis (CVT) are not fully understood. Diffusion-weighted imaging (DWI) findings in a 34-year old woman with deep cerebral venous thrombosis are described. Recent literature concerning DWI and cerebral venous thrombosis is also reviewed. A MRI performed within 7 hours from onset revealed hyperintensities in deep grey matter bilaterally (FLAIR/T2), without changes in ADC maps, suggesting vasogenic edema. After anticoagulation a new MRA disclosed complete recanalization of venous thrombosis. Despite her good clinical outcome the MRI showed hemorrhagic lesions suggesting venous infarct. Lesions detected in acute CVT with DWI may have normal ADC values. There is no good correlation between the acute ADC values and clinical and radiological evolution. The prognostic value of ADC in the acute phase of CVT remains unsettled.