Comparing Antenatal and Delivery Care Services in Public and Private Health Facilities: Evidence from 2018 Nigeria Demographic and Health Survey.

BACKGROUND: There have been calls for privatisation of public health facilities to improve quality of care received. The study compared antenatal and delivery services received in public and private health facilities in Nigeria. METHODS: The study was based on 2018 Nigeria Demographic and Health Survey data collected from women aged 15-49 years, concerning their pregnancy and delivery. Data on those that attended antenatal clinic (ANC) in public or private facilities and had live births in the preceding five years was analysed. Simple logistic regression was used to test for association between type of facility for ANC and delivery and the care received. RESULTS: A total of 15,811 women attended ANC in public (12,921, 81.7%) and private (2,890, 18.3%) facilities, and 12,399 delivered in public (8,583, 69.2%) and private (3,817, 30.8%) facilities. Type of facility attended was associated with number of ANC visits (OR=3.89; p<0.001), blood sample taken (OR=1.16; p=0.029), iron supplementation (OR=0.49; p<0.001), deworming (OR=0.74; p<0.001), receiving all the components of ANC service (OR=0.79; p<0.001), and skilled birth attendance (OR=3.81; p<0.001). However, it was not associated with blood pressure measurement (OR=1.07; p=0.459), urine sample taken (OR=1.05; p=0.486), postnatal check (OR=0.94; p=0.171) and timing of postnatal check (OR=0.73; p=0.185). CONCLUSION: While private facilities had more ANC visits and skilled birth attendance, overall provision of ANC services was better in the public facilities. Therefore, antenatal and delivery services were not necessarily better in private facilities. Beyond availability, further studies are needed to compare the quality of antenatal and delivery services in public and private facilities.

CONTEXTE: Il y a eu des appels à la privatisation des établissements de santé publics pour améliorer la qualité des soins reçus. L'étude a comparé les services prénatals et d'accouchement reçus dans les établissements de santé publics et privés au Nigéria. MÉTHODES: L'étude était basée sur les données de l'enquête démographique et de santé du Nigéria de 2018 collectées auprès de femmes âgées de 15 à 49 ans, concernant leur grossesse et leur accouchement. Les données sur les personnes ayant fréquenté une clinique prénatale (CPN) dans des établissements publics ou privés et ayant eu des naissances vivantes au cours des cinq années précédentes ont été analysées. Une régression logistique simple a été utilisée pour tester l'association entre le type d'établissement pour les soins prénatals et l'accouchement et les soins reçus. RÉSULTATS: Un total de 15 811 femmes ont assisté à des soins prénatals dans des établissements publics (12921, 81,7%) et privés (2890, 18,3%), et 12399 dans des établissements publics (8583, 69,2%) et privés (3817, 30,8%). Le type d'établissement fréquenté était associé au nombre de consultations prénatales (OR = 3,89; p <0,001), à un échantillon de sang prélevé (OR = 1,16; p = 0,029), à la supplémentation en fer (OR = 0,49; p <0,001), au déparasitage (OR = 0,74; p <0,001), recevant tous les composants du service ANC (OR = 0,79; p <0,001), et assistance à la naissance (OR = 3,81; p <0,001). Cependant, il n'était pas associé à la mesure de la pression artérielle (OR = 1,07; p = 0,459), à l'échantillon d'urine prélevé (OR = 1,05; p = 0,486), au contrôle postnatal (OR = 0,94; p = 0,171) et au moment du contrôle postnatal ( OR = 0,73; p = 0,185). CONCLUSION: Alors que les établissements privés avaient plus de visites prénatales et une assistance à l'accouchement qualifiée, la prestation globale des services prénatals était meilleure dans les établissements publics. Par conséquent, les services prénatals et d'accouchement n'étaient pas nécessairement meilleurs dans les établissements privés. Au-delà de la disponibilité, d'autres études sont nécessaires pour comparer la qualité des services prénatals et d'accouchement dans les établissements publics et privés.

Knowledge and perception of episiotomy among women attending antenatal clinic in a secondary health facility in North-West Nigeria.

BACKGROUND: Episiotomy is a common surgical procedure experienced by women worldwide to ease labor and improve its outcome. However, it could influence the use of delivery services because of its associated complications. The study assessed knowledge and perception of episiotomy among antenatal clinic (ANC) attendees. METHODS: It was a cross-sectional study conducted among 218 women attending ANC in a secondary health facility in Northwestern Nigeria. Data were collected using a structured, interviewer-administered questionnaire and were analyzed using IBM SPSS Statistics 20. RESULTS: The mean age of women attending ANC was 24.2 ± 6.6 years, and 31 (14.2%) of them had had an episiotomy in the past. A majority of them were aware of episiotomy (87.6%) and had good knowledge (83.5%) and good perception (77.5%) of it. In addition, a majority (89.0%) were willing to deliver at the facility even if episiotomy would be given during labor. Knowledge of episiotomy showed statistically significant association with only a history of previous delivery while perception did not show statistically significant association with any of the independent variables. CONCLUSIONS: Awareness and knowledge of episiotomy among women attending ANC were high and perception of it was generally good. The major factor associated with the knowledge of episiotomy was a history of previous delivery. Effort should be channeled toward improving awareness and knowledge on episiotomy among intending mothers, and health workers should always ensure that women are adequately informed and counseled before an episiotomy is given to them.

Integrated injection seeded terahertz source and amplifier for time-domain spectroscopy.

We used a terahertz (THz) quantum cascade laser (QCL) as an integrated injection seeded source and amplifier for THz time-domain spectroscopy. A THz input pulse is generated inside a QCL by illuminating the laser facet with a near-IR pulse from a femtosecond laser and amplified using gain switching. The THz output from the QCL is found to saturate upon increasing the amplitude of the THz input power, which indicates that the QCL is operating in an injection seeded regime.

Debridement, antibiotics, and implant retention in non-oncological femoral megaprosthesis infections: minimum 5 year follow-up.

PURPOSE: Megaprostheses are increasingly utilised outside of the oncological setting, and remain at significant risk of periprosthetic joint infection (PJI). Debridement, antibiotic, and implant retention (DAIR) is an established treatment for PJI, however its use in non-oncological patients with femoral megaprostheses has not been widely reported. There are significant differences in patient physiology, treatment goals, and associated risks between these patient cohorts. METHODS: We identified 14 patients who underwent DAIR for a PJI of their femoral megaprostheses, between 2000 and 2014, whom had their index procedure secondary to non-oncological indications. Patients were managed as part of a multidisciplinary team, with our standardised surgical technique including exchange of all mobile parts, and subsequent antibiotic therapy for a minimum of 3 months. Patients were followed up for a minimum of 5 years. RESULTS: Patients included six proximal femoral replacements, five distal femoral replacements, and three total femoral replacements. No patients were lost to follow-up. There were six males and eight females, with a mean age of 67.2 years, and mean ASA of 2.3. Nine patients (64.3%) successfully cleared their infection following DAIR at a minimum of 5 year follow-up. Five patients (35.7%) required further revision surgery, with four patients cleared of infection. No patients who underwent DAIR alone suffered complications as a result of the procedure. CONCLUSIONS: The use of DAIR in these complex patients can lead to successful outcomes, but the risk of further revision remains high. The success rate (64.3%) remains on par with other studies evaluating DAIR in megaprostheses and in primary arthroplasty. This study indicates judicious use of DAIR can be an appropriate part of the treatment algorithm. LEVEL OF EVIDENCE: II.

Genotoxic effects of Dukhan: A smoke bath from the wood of Acacia seyal used traditionally by Sudanese women.

ETHNOBOTANICAL RELEVANCE: Smoke from the wood of Acacia seyal Delile has been used by Sudanese women for making a smoke bath locally called Dukhan. The ritual is performed to relieve rheumatic pain, smooth skin, heal wounds and achieve general body relaxation. AIM OF THE STUDY: The present study was designed to investigate the in vitro anti-inflammatory effect of the smoke condensate using cyclooxygenase -1 (COX-1) and -2 (COX-2) as well as its potential genotoxic effects using the bacterial-based Ames test and the mammalian cells-based micronucleus/cytome and comet assays. MATERIAL AND METHODS: The smoke was prepared in a similar way to that commonly used traditionally by Sudanese women then condensed using a funnel. Cyclooxygenase assay was used to evaluate its in vitro anti-inflammatory activity. The neutral red uptake assay was conducted to determine the range of concentrations in the mammalian cells-based assays. The Ames, cytome and comet assays were used to assess its potential adverse (long-term) effects. RESULTS: The smoke condensate did not inhibit the cyclooxygenases at the highest concentration tested. All smoke condensate concentrations tested in the Salmonella/microsome assay induced mutation in both TA98 and TA100 in a dose dependent manner. A significant increase in the frequency of micronucleated cells, nucleoplasmic bridges and nuclear buds was observed in the cytome assay as well as in the % DNA damage in the comet assay. CONCLUSIONS: The findings indicated a dose dependent genotoxic potential of the smoke condensate in the bacterial and human C3A cells and may pose a health risk to women since the smoke bath is frequently practised. The study highlighted the need for further rigorous assessment of the risks associated with the smoke bath practice.

Bifunctional Composites for Biofilms Modulation on Cervical Restorations.

Cervical composites treating root carious and noncarious cervical lesions usually extend subgingivally. The subgingival margins of composites present poor plaque control, enhanced biofilm accumulation, and cause gingival irritation. A potential material to restore such lesions should combine agents that interfere with bacterial biofilm development and respond to acidic conditions. Here, we explore the use of new bioresponsive bifunctional dental composites against mature microcosm biofilms derived from subgingival plaque samples. The designed formulations contain 2 bioactive agents: dimethylaminohexadecyl methacrylate (DMAHDM) at 3 to 5 wt.% and 20 wt.% nanosized amorphous calcium phosphate (NACP) in a base resin. Composites with no DMAHDM and NACP were used as controls. The newly formulated 5% DMAHDM-20% NACP composite was analyzed by micro-Raman spectroscopy and transmission electron microscopy. The wettability and surface-free energy were also assessed. The inhibitory effect on the in vitro biofilm growth and the 16S rRNA gene sequencing of survival bacterial colonies derived from the composites were analyzed. Whole-biofilm metabolic activity, polysaccharide production, and live/dead images of the biofilm grown over the composites complement the microbiological assays. Overall, the designed formulations had higher contact angles with water and lower surface-free energy compared to the commercial control. The DMAHDM-NACP composites significantly inhibited the growth of total microorganisms, Porphyromonas gingivalis, Prevotella intermedia/nigrescens, Aggregatibacter actinomycetemcomitans, and Fusobacterium nucleatum by 3 to 5-log (P < 0.001). For the colony isolates from control composites, the composition was typically dominated by the genera Veillonella, Fusobacterium, Streptococcus, Eikenella, and Leptotrichia, while Fusobacterium and Veillonella dominated the 5% DMAHDM-20% NACP composites. The DMAHDM-NACP composites contributed to over 80% of reduction in metabolic and polysaccharide activity. The suppression effect on plaque biofilms suggested that DMAHDM-NACP composites might be used as a bioactive material for cervical restorations. These results may propose an exciting path to prevent biofilm growth and improve dental composite restorations' life span.

Voltammetric and spectroscopic studies on binding of antitumor Morin, Morin-Cu complex and Morin-beta-cyclodextrin with DNA.

A systematic comparative study of the binding of antitumor Morin and its complexes with DNA has been investigated in the Britton-Robison (BR) buffer solutions using voltammetric and spectroscopic methods. The results show that Morin molecule, acting as an intercalator, is inserted into the cavity of the beta-cyclodextrin (beta-CD) as well as into the base stacking domain of the DNA double helix. The interaction of Morin-Cu complex or the inclusion complex of Morin-beta-CD with ds-DNA causes hypochromism in the absorption spectra, along with pronounced changes in the electrochemical behavior of the Morin complexes. An isobestic point and a new spectrum band appeared indicating the formation of the new system of Morin-Cu-DNA at lambda(m)=391 nm and Morin-beta-CD-DNA at lambda(m)=375 nm. The intercalation of Morin-Cu and Morin-beta-CD complexes with DNA produces an electrochemically inactive supramolecular complex. The binding constants were calculated from the increase of the solubility, the strong hypochromism, and the decrease in peak current of Morin and its complexes upon the addition of the host molecules. Calculation of the thermodynamic parameters of the interaction of the inclusion complex of Morin-beta-CD with DNA, including Gibbs free energy change, Helmholz free energy and entropy change shows that the complexation is a spontaneous process of association.

Outcomes of repeat two-stage exchange hip arthroplasty for prosthetic joint infection.

AIMS: The increasing infection burden after total hip arthroplasty (THA) has seen a rise in the use of two-stage exchange arthroplasty and the use of increasingly powerful antibiotics at the time of this procedure. As a result, there has been an increase in the number of failed two-stage revisions during the past decade. The aim of this study was to clarify the outcome of repeat two-stage revision THA following a failed two-stage exchange due to recurrent prosthetic joint infection (PJI). PATIENTS AND METHODS: We identified 42 patients who underwent a two-stage revision THA having already undergone at least one previous two stage procedure for infection, between 2000 and 2015. There were 23 women and 19 men. Their mean age was 69.3 years (48 to 81). The outcome was analyzed at a minimum follow-up of two years. RESULTS: A satisfactory control of infection and successful outcome was seen in 26 patients (57%). There therefore remained persistent symptoms that either required further surgery or chronic antibiotic suppression in 16 patients (38%). One-third of patients had died by the time of two years' follow-up. CONCLUSION: The rate of failure and complication rate of repeat two-stage exchange THA for PJI is high and new methods of treatment including host optimization, immunomodulation, longer periods between stages, and new and more powerful forms of antimicrobial treatment should be investigated. Cite this article: Bone Joint J 2019;101-B(6 Supple B):110-115.

The usefulness of the platelet function analyser (PFA-100) in screening for underlying bleeding disorders in women with menorrhagia.

The prevalence of underlying bleeding disorders is common in women with menorrhagia. This was a prospective study to screen for the underlying bleeding disorders in women presenting with menorrhagia by using the PFA-100 and comparing the accuracy of the results with the complete haematological assays. A total of 62 women referred to gynaecology outpatients with a history of heavy, regular periods had blood collected for analysis by the PFA-100 and also a full coagulation profile including von Willebrand factor. PFA-100 analysis suggested platelet defects in 10 (16%) women. This included five (8%) identified with von Willebrand disease, two (3.2%) with storage pool disorders and three (4.8%) without any recognisable platelet or bleeding disorders after a full coagulation profile, including von Willebrand factor, was carried out. PFA-100 results had a sensitivity of 100% and specificity of 94.8% in our study. We conclude that PFA-100 is a quick and reliable method of screening for impaired haemostasis in patients with menorrhagia.

Two-stage revision for the culture-negative infected total hip arthroplasty : A comparative study.

AIMS: Periprosthetic joint infection (PJI) remains a challenging complication following total hip arthroplasty (THA). It is associated with high levels of morbidity, mortality and expense. Guidelines and protocols exist for the management of culture-positive patients. Managing culture-negative patients with a PJI poses a greater challenge to surgeons and the wider multidisciplinary team as clear guidance is lacking. PATIENTS AND METHODS: We aimed to compare the outcomes of treatment for 50 consecutive culture-negative and 50 consecutive culture-positive patients who underwent two-stage revision THA for chronic infection with a minimum follow-up of five years. RESULTS: There was no significant difference in the outcomes between the two groups of patients, with a similar rate of re-infection of 6%, five years post-operatively. Culture-negative PJIs were associated with older age, smoking, referral from elsewhere and pre-operative antibiotic treatment. The samples in the culture-negative patients were negative before the first stage (aspiration), during the first-stage (implant removal) and second-stage procedures (re-implantation). CONCLUSION: Adherence to strict protocols for selecting and treating culture-negative patients with a PJI using the same two-stage revision approach that we employ for complex culture-positive PJIs is important in order to achieve control of the infection in this difficult group of patients. Cite this article: Bone Joint J 2018;(1 Supple A)100-B:3-8.

Blood Hematological and Biochemical Constituents, Antioxidant Enzymes, Immunity and Lymphoid Organs of Broiler Chicks Supplemented with Propolis, Bee Pollen and Mannan Oligosaccharides Continuously or Intermittently.

This study investigate the effect of bee pollen (BP) and/or propolis (Pro) as an alternative to Mannan oligosaccharides (Bio-MOS, a hydrolyzed yeast with natural and artificial flavors Alltech Inc) when given continuously or intermittently on antioxidant enzymes, immunity, weight and morphology of lymphoid organs of broilers. Thus, 324 unsexed one-day-old Arbor Acres broilers were randomly distributed into nine treatment groups, each replicated 6 times of 6 birds per replicate. The chicks were kept in wire cages and fed the same basal diet and were submitted to the following treatments: control without supplementation (control) or supplemented with BP at 300 mg, Pro at 300 mg, BP+Pro at 300 mg each and Bio-MOS at 0.5 g/kg diet. Each supplemented group was subdivided into two subgroups in which the additives were supplied continuously or intermittently. In the continuously supplemented groups, supplementations were given from one till 36 days of age, and in the intermittently supplemented groups, the administration was only three days before, on the day of and day after vaccination. The BP and Pro supplied continuously or intermittently was equally potent for improving immunity, antioxidant enzymes similar to Bio-MOS. All supplements supplied either continuously or intermittently resulted a significantly higher thymus (P < .04) and bursa weights (P < .001) than the control group. Combining BP with Pro resulted in a further increase in thymus weights and small follicle diameter compared to the control group. In addition, thymus percentage in the group received BP+Pro showed a further increase compared to the control and Pro supplemented intermittently. Bio-MOS, when supplied continuously or intermittently, resulted in the greatest response in splenic lymphoblasts. Supplementation with either BP or Pro intermittently, is adequate to promote health and immune response of broiler chicks, with 40% saving of supplementation costs.

Anolignan B: a bioactive compound from the roots of Terminalia sericea.

Antibacterial bioassay-guided fractionation of an ethyl acetate root extract of Terminalia sericea led to the isolation of anolignan B. The isolated compound was further tested for anti-inflammatory activity using the cyclooxygenase enzyme assays (COX-1 and COX-2) and for potential mutagenic effects using the Ames test. In the antibacterial test, anolignan B showed activity against both Gram-positive and Gram-negative bacteria. The minimum inhibitory concentration values obtained (MIC) ranged from 3.8 microg/ml against Bacillus subtilis (Gram-positive) to 31 microg/ml against Escherichia coli (Gram-negative). In the anti-inflammatory assays, anolignan B showed activity against both COX-1 (IC(50) = 1.5 mM) and COX-2 (IC(50) = 7.5 mM) enzymes. No potential mutagenic effects were observed in the Salmonella microsome assay (TA98). Isolation of anolignan B from Terminalia sericea as well as the antibacterial and anti-inflammatory activities observed in this study has not been reported previously.

Financial analysis of revision knee surgery based on NHS tariffs and hospital costs: does it pay to provide a revision service?

Revision total knee arthroplasty (TKA) is a complex procedure which carries both a greater risk for patients and greater cost for the treating hospital than does a primary TKA. As well as the increased cost of peri-operative investigations, blood transfusions, surgical instrumentation, implants and operating time, there is a well-documented increased length of stay which accounts for most of the actual costs associated with surgery. We compared revision surgery for infection with revision for other causes (pain, instability, aseptic loosening and fracture). Complete clinical, demographic and economic data were obtained for 168 consecutive revision TKAs performed at a tertiary referral centre between 2005 and 2012. Revision surgery for infection was associated with a mean length of stay more than double that of aseptic cases (21.5 vs 9.5 days, p < 0.0001). The mean cost of a revision for infection was more than three times that of an aseptic revision (£30 011 (sd 4514) vs £9655 (sd 599.7), p < 0.0001). Current NHS tariffs do not fully reimburse the increased costs of providing a revision knee surgery service. Moreover, especially as greater costs are incurred for infected cases. These losses may adversely affect the provision of revision surgery in the NHS.

A micromethod for evaluating the phagocytic activity of human macrophages by ingestion of radio-labelled polystyrene particles.

Studies in vitro of human macrophage function in health and disease have been impeded by the difficulty of obtaining such cells in sufficient number. Unlike animal species, the only readily available source of human macrophages are circulating monocytes. Herein, a method is described whereby the phagocytic rate of small numbers of glass-adherent mononuclear cells can be accurately measured. The method utilizes the ingestion by macrophages of technetium labelled polystyrene particles; both the radiolabel and ingestible substrate are readily available and the labelling process simple and efficient. The phagocytic rate can be expressed as radioactive counts per microgram of cell protein; data is also presented showing that the number of particles ingested per cell can be accurately derived.

Surface-associated antigens of Brugia malayi L2 and L3 parasites during vector-stage development.

Surface and metabolic labeling procedures were used to characterize the composition and the time of expression of Brugia malayi L2 and L3 surface-associated molecules as the larvae develop within the mosquito vector. Larvae were harvested from mosquito tissues at 5 (early L2), 8 (late L2) and 11 (L3) days post-infection and labeled with 125I-Iodo-Gen. The results of one-dimensional analysis showed that there is a progressive increase in the complexity of peptides associated with the surface of developing larvae, culminating in the expression of 7 major labeled components on L3s. Both L2 and L3 parasites have surface-associated components of 42, 35, 33, 19 and 17 kDa. Between days 8 and 11 of development in the insect vector, Brugia malayi undergoes the L2 to L3 molt and acquires additional major immunogenic peptides of 40 and 22 kDa. Two-dimensional analyses of extracts from 125I-labeled L2s and L3s revealed that the major 35-, 33-, 19- and 17-kDa molecules are part of a peptide complex that forms a 'ladder' between 17 and 150 kDa. To gain information on the times during which the major surface-associated molecules are produced by the parasite, larvae were labeled with [35S]methionine either in situ as they developed within the mosquito or during culture after exiting the vector. For in situ labeling, [35S]methionine was introduced into the hemolymph of infected mosquitoes by micro-injection at days 2, 5 and 8 post-infection and the larvae were allowed to develop for an additional 3 days. The results of 1- and 2-dimensional analyses of [35S]methionine-labeled extracts from vector-stage or post-vector-stage larvae indicate that the molecules associated with the surface of B. malayi L3s are synthesized between day 5 and day 11 of development in the insect host. Immediately after the larvae exit the vector, the synthesis of the 40 and 22-kDa peptides is drastically reduced or terminated.

Dirofilaria immitis: studies on anti-microfilarial immunity in Lewis rats.

The effect of vaccination on rates of microfilarial clearance using Dirofilaria immitis in male Lewis rats was examined. Animals were immunized with whole, dead microfilariae or a PBS extract of microfilariae in Freund's adjuvant. The immunized animals, as well as untreated and adjuvant controls, were challenged intravenously with 4 x 10(5) viable microfilariae (mf). The duration of microfilaremia was 15.5 days in rats vaccinated with whole mf, 17.7 days in those vaccinated with a PBS extract, 36.3 days for those vaccinated with adjuvant alone, and greater than 70 days for the untreated group. Analysis of the anti-microfilarial IgG response by ELISA and Western blots demonstrated that immunization induced significant amounts of antibody against high molecular weight peptides, particularly a peptide located at 105 kDa. Antibody levels in both groups of immunized animals continued to rise following challenge, reaching peak levels of 78-80 micrograms/ml on the day of microfilarial clearance. Decreasing microfilaremia following challenge was associated with an enhanced recognition of low molecular weight peptides.

Detection of Francisella tularensis in infected mammals and vectors using a probe-based polymerase chain reaction.

We investigated the use of a TaqMan 5' nuclease assay (5NA) directed against the Francisella tularensis outer membrane protein (Fop) gene and a polymerase chain reaction-enzyme immunoassay (PCR-EIA) directed against the tul 4 gene for detection of this organism in experimentally infected mice and in field-collected tick vectors. We also evaluated the use of specially formulated filter paper (FTA) for rapid sample preparation. The 5NA had a detection limit of 1 pg of genomic DNA (<100 colony-forming units) and could be completed within several hours. The PCR-EIA could detect 1 pg of genomic DNA and 10 attograms (ag) (22 copies) of cloned insert, but takes longer to perform. Both assays were genus-specific, and successfully detected F. tularensis in mouse tissues (5NA) and in tick extracts (PCR-EIA). The FTA paper provided inexpensive, rapid, template preparation for the tick extracts, mouse tissues, and DNA obtained from clinical specimens. These probe-based assays have the potential to provide rapid, real-time/high-throughput molecular diagnostics in field situations.

Surface-associated antigens of second, third and fourth stage larvae of Dirofilaria immitis.

The surface-associated molecules of the second (L2), third (L3) and fourth (L4) larval stages of Dirofilaria immitis were characterized employing radiolabeling techniques and SDS-PAGE analysis. Major labeled components of 35 kDa and 6 kDa were present in extracts from IODO-GEN-labeled L2 and L3 parasites. The results of lactoperoxidase-catalyzed reactions also demonstrated that L2 and L3 stages of D. immitis have a similar repertoire of surface-associated antigens. However, in contrast to the results obtained with IODO-GEN, lactoperoxidase reactions labeled components with apparent molecular weights of 66, 48, 25, 16.5 and 12 kDa. The similarities in the molecular weights of the L2 and L3 surface-associated components and the results of immunoprecipitation experiments which demonstrated that antibodies produced against the 35 kDa molecule from D. immitis L3s also recognize the 35 kDa component from L2 parasites suggest that synthesis of the molecules found at the surface of mature infective larvae begins as early as day 6 of development in the mosquito, D. immitis L4s emerged from the molting process with a repertoire of surface-associated antigens distinct from those found on L2s and L3s. IODO-GEN labeling of D. immitis L4s showed major surface-associated molecules with apparent molecular weights of 57, 40, 25, 12 and 10 kDa when analyzed under non-reducing conditions. In addition to molecules of 57, 40, 25, 12 and 10 kDa, extracts of D. immitis L4s labeled with lactoperoxidase contained additional major bands at 45, 43 and 8 kDa. Metabolic labeling experiments demonstrated a shift in the amount and complexity of the excretory/secretory products released by D. immitis during L3 to L4 development.

Anti-Onchocerca volvulus immunoglobulin subclass response in children from Sierra Leone.

The humoral immune responses of a paediatric population of 224 children, 2-15 years of age, residing in an onchocerciasis endemic area of Sierra Leone, were studied to gain information that may be useful in the serodiagnosis of prepatent and low-level infections with Onchocerca volvulus. The antigen-specific levels of IgG and IgG4 were determined and evaluated in the context of the parasitological status of the child. Over 87% of the microfilaria-negative children had significant levels of antigen-specific antibodies against O. volvulus, suggesting that a large percentage of this paediatric population were harbouring prepatent or low-level infections. Over 60% of the children in the group that had detectable numbers of microfilariae in skin snips had elevated levels of O. volvulus-specific IgG4. In contrast, only 23% of the microfilaria-negative children had detectable IgG4 responses. The results presented here indicate that measures of O. volvulus-specific IgG4 may be a useful indicator of the parasitological status of children during the very early stages of onchocerciasis.

Muscle actin gene from Aedes aegypti (Diptera:Culicidae).

A recombinant phagemid containing a 1,240-bp insert encoding an actin was isolated from a yellow fever mosquito, Aedes aegypti (L.), complementary DNA library. This insert (pBS-Act35) contained an open reading frame of 822 bp whose deduced amino acid sequence exhibited > 95% homology with the carboxyl terminal 274 amino acids of Drosophila melanogaster Meigen and silkworm, Bombyx mori (L.), actin genes. Reverse transcriptase-polymerase chain reaction was used to clone and determine the sequence of the additional 306 nucleotides that comprise the 5' end of the gene. The coding nucleotide sequence of the whole gene (designated Aeact-1) exhibited between 81 and 89% homology with coding sequences of D. melanogaster and B. mori actin genes, and its deduced amino acid sequence exhibited > 95% homology with those genes. The highest similarity of Aeact-1 gene at the amino acid sequence level was with B. mori and D. melanogaster muscle actins. Southern blot analysis indicated that the Aedes genome contains at least 5 actin-related sequences.