Immune responses to Sinopharm/BBIBP-CorV in individuals in Sri Lanka

As there are limited data of the immunogenicity of the Sinopharm/BBIBP-CorV in different populations, antibody responses against different SARS-CoV-2 variants of concern and T cell responses, we investigated the immunogenicity of the vaccine, in individuals in Sri Lanka. SARS-CoV-2-specific antibodies were measured in 282 individuals who were seronegative at baseline, and ACE2 receptor blocking antibodies, antibodies to the receptor-binding domain (RBD) of the wild-type (WT), alpha, beta and delta variants, ex vivo and cultured IFNγ ELISpot assays, intracellular cytokine secretion assays and B cell ELISpot assays were carried out in a sub cohort of the vaccinees at 4 and 6 weeks (2 weeks after the second dose). Ninety-five percent of the vaccinees seroconverted, although the seroconversion rates were significantly lower (p < 0.001) in individuals >60 years (93.3%) compared to those who were 20-39 years (98.9%); 81.25% had ACE2 receptor blocking antibodies at 6 weeks, and there was no difference in these antibody titres in vaccine sera compared to convalescent sera (p = 0.44). Vaccinees had significantly less (p < 0.0001) antibodies to the RBD of WT and alpha, although there was no difference in antibodies to the RBD of beta and delta compared to convalescent sera; 27.7% of 46.4% of vaccinees had ex vivo IFNγ and cultured ELISpot responses respectively, and IFNγ and CD107a responses were detected by flow cytometry. Sinopharm/BBIBP-CorV appeared to induce a similar level of antibody responses against ACE2 receptor, delta and beta as seen following natural infection.

Mosaic RBD nanoparticles protect against challenge by diverse sarbecoviruses in animal models

To combat future severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants and spillovers of SARS-like betacoronaviruses (sarbecoviruses) threatening global health, we designed mosaic nanoparticles that present randomly arranged sarbecovirus spike receptor-binding domains (RBDs) to elicit antibodies against epitopes that are conserved and relatively occluded rather than variable, immunodominant, and exposed. We compared immune responses elicited by mosaic-8 (SARS-CoV-2 and seven animal sarbecoviruses) and homotypic (only SARS-CoV-2) RBD nanoparticles in mice and macaques and observed stronger responses elicited by mosaic-8 to mismatched (not on nanoparticles) strains, including SARS-CoV and animal sarbecoviruses. Mosaic-8 immunization showed equivalent neutralization of SARS-CoV-2 variants, including Omicrons, and protected from SARS-CoV-2 and SARS-CoV challenges, whereas homotypic SARS-CoV-2 immunization protected only from SARS-CoV-2 challenge. Epitope mapping demonstrated increased targeting of conserved epitopes after mosaic-8 immunization. Together, these results suggest that mosaic-8 RBD nanoparticles could protect against SARS-CoV-2 variants and future sarbecovirus spillovers.

Kinetics of immune responses to SARS-CoV-2 proteins in individuals with varying severity of infection and following a single dose of the AZD1222

To characterize the IgG and IgA responses to different SARS-CoV-2 proteins, we investigated the antibody responses to SARS-CoV-2 following natural infection and following a single dose of AZD1222 (Covishield), in Sri Lankan individuals. The IgG and IgA responses were assessed to S1, S2, RBD, and N proteins in patients at 4 weeks and 12 weeks since the onset of illness or following vaccination. Antibodies to the receptor-binding domain of SARS-CoV-2 wild type (WT), α, β, and λ and ACE2 (Angiotensin Converting Enzyme 2) receptor blocking antibodies were also assessed in these cohorts. For those with mild illness and in vaccines, the IgG responses to S1, S2, RBD, and N protein increased from 4 weeks to 12 weeks, while it remained unchanged in those with moderate/severe illness. In the vaccines, IgG antibodies to the S2 subunit had the highest significant rise (P < 0.0001). Vaccines had several-fold lower IgA antibodies to all the SARS-CoV-2 proteins tested than those with natural infection. At 12 weeks, the haemagglutination test (HAT) titres were significantly lower to the α in vaccines and significantly lower in those with mild illness and in vaccines to β and for λ. No such difference was seen in those with moderate/severe illness. Vaccines had significantly less IgA to SARS-CoV-2, but comparable IgG responses those with natural infection. However, following a single dose vaccines had reduced antibody levels to the VOCs, which further declined with time, suggesting the need to reduce the gap between the two doses, in countries experiencing outbreaks due to VOCs.

Persistence of immune responses to the Sinopharm/BBIBP-CorV vaccine

BACKGROUND

To determine the kinetics and persistence of immune responses following the Sinopharm/BBIBP-CorV, we investigated immune responses in a cohort of Sri Lankan individuals.

METHODS

SARS-CoV-2 specific total antibodies were measured in 20-39 years (n = 61), 40-59 years (n = 120) and those >60 years of age (n = 22) by enzyme-linked immunosorbent assay, 12 weeks after the second dose of the vaccine. Angiotensin-converting enzyme 2 (ACE2) receptor blocking antibodies (ACE2R-Ab), antibodies to the receptor-binding domain (RBD) of the ancestral virus (WT) and variants of concern, were measured in a sub cohort. T cell responses and memory B cell responses were assessed by ELISpot assays.

RESULTS

A total of 193/203 (95.07%) of individuals had detectable SARS-CoV-2 specific total antibodies, while 67/110 (60.9%) had ACE2R-Ab. A total of 14.3%-16.7% individuals in the 20-39 age groups had detectable antibodies to the RBD of the WT and variants of concern, while the positivity rates of those ≥60 years of age was <10%. A total of 14/49 (28.6%) had Interferon gamma ELISpot responses to overlapping peptides of the spike protein, while memory B cell responses were detected in 9/20 to the S1 recombinant protein. The total antibody levels and ACE2R-Ab declined from 2 to 12 weeks from the second dose, while ex vivo T cell responses remained unchanged. The decline in ACE2R-Ab levels was significant among the 40-59 (p = .0007) and ≥60 (p = .005) age groups.

CONCLUSIONS

Antibody responses declined in all age groups, especially in those ≥60 years, while T cell responses persisted. The effect of waning of immunity on hospitalization and severe disease should be assessed by long term efficacy studies.

Kinetics of immune responses to the AZD1222/Covishield vaccine with varying dose intervals in Sri Lankan individuals

BACKGROUND

To understand the kinetics of immune responses with different dosing gaps of the AZD1222 vaccine, we compared antibody and T cell responses in two cohorts with two different dosing gaps.

METHODS

Antibodies to the SARS-CoV-2 virus were assessed in 297 individuals with a dosing gap of 12 weeks, sampled 12 weeks post second dose (cohort 1) and in 77 individuals with a median dosing gap of 21.4 weeks (cohort 2) sampled 6 weeks post second dose. ACE2-blocking antibodies (ACE2-blocking Abs), antibodies to the receptor-binding domain (RBD) of  variants of concern (VOC), and ex vivo T cell responses were assessed in a subcohort.

RESULTS

All individuals (100%) had SARS-CoV-2-specific total antibodies and 94.2% of cohort 1 and 97.1% of cohort 2 had ACE2-blocking Abs. There was no difference in antibody titers or positivity rates in different age groups in both cohorts. The ACE2-blocking Abs (p < .0001) and antibodies to the RBD of the VOCs were significantly higher in cohort 2 compared to cohort 1. 41.2% to 65.8% of different age groups gave a positive response by the hemagglutination assay to the RBD of the ancestral virus and VOCs in cohort 1, while 53.6%-90% gave a positive response in cohort 2. 17/57 (29.8%) of cohort 1 and 17/29 (58.6%) of cohort 2 had ex vivo interferon (IFN)γ ELISpot responses above the positive threshold. The ACE2-blocking antibodies (Spearman's r = .46, p = .008) and ex vivo IFNγ responses (Spearman's r = .71, p < .0001) at 12 weeks post first dose, significantly correlated with levels 12 weeks post second dose.

CONCLUSIONS

Both dosing schedules resulted in high antibody and T cell responses post vaccination, although those with a longer dosing gap had a higher magnitude of responses, possibly as immune responses were measured 6 weeks post second dose compared to 12 weeks post second dose.

Mosaic RBD nanoparticles protect against multiple sarbecovirus challenges in animal models

To combat future SARS-CoV-2 variants and spillovers of SARS-like betacoronaviruses (sarbecoviruses) threatening global health, we designed mosaic nanoparticles presenting randomly-arranged sarbecovirus spike receptor-binding domains (RBDs) to elicit antibodies against conserved/relatively-occluded, rather than variable/immunodominant/exposed, epitopes. We compared immune responses elicited by mosaic-8 (SARS-CoV-2 and seven animal sarbecoviruses) and homotypic (only SARS-CoV-2) RBD-nanoparticles in mice and macaques, observing stronger responses elicited by mosaic-8 to mismatched (not on nanoparticles) strains including SARS-CoV and animal sarbecoviruses. Mosaic-8 immunization showed equivalent neutralization of SARS-CoV-2 variants including Omicron and protected from SARS-CoV-2 and SARS-CoV challenges, whereas homotypic SARS-CoV-2 immunization protected only from SARS-CoV-2 challenge. Epitope mapping demonstrated increased targeting of conserved epitopes after mosaic-8 immunization. Together, these results suggest mosaic-8 RBD-nanoparticles could protect against SARS-CoV-2 variants and future sarbecovirus spillovers.

Immune responses following the first dose of the Sputnik V (Gam-COVID-Vac)

As the first dose of Gam-COVID-Vac, is currently used as a single dose vaccine in some countries, we investigated the immunogenicity of this at 4 weeks (327 naïve individuals). 88.7% seroconverted, with significantly lower seroconversion rates in those over 60 years (p = 0.004) and significantly lower than previously seen with AZD1222 (p = 0.018). 82.6% developed ACE2 receptor blocking antibodies, although levels were significantly lower than following natural infection (p = 0.0009) and a single dose of AZD1222 (p < 0.0001). Similar titres of antibodies were observed to the receptor binding domain of WT, B.1.1.7 and B.1.617.2 compared to AZD1222, while the levels for B.1.351 were significantly higher (p = 0.006) for Gam-COVID-Vac. 30% developed ex vivo IFNγ ELISpot responses (significantly lower than AZD1222), and high frequency of CD107a expressing T cells along with memory B cell responses. Although single dose of Gam-COVID-Vac was highly immunogenic, administration of a second dose is likely to be beneficial.

Seroprevalence of SARS-CoV-2 Infection in the Colombo Municipality Region, Sri Lanka

Background: As the Municipality Council area in Colombo (CMC) experienced the highest number of cases until the end of January 2021, in Sri Lanka, we carried out a serosurvey prior to initiation of the vaccination program to understand the extent of the SARS-CoV-2 outbreak.

Methods: SARS-CoV-2 seropositivity was determined in 2,547 individuals between the ages of 10–86 years, by the Wantai total antibody ELISA. We also compared seroprevalence using the haemagglutination test (HAT) to evaluate its usefulness in carrying out serosurveys.

Results: The overall seropositivity rate was 24.46%, while seropositivity by HAT was 18.90%. Although The SARS-CoV-2 infection detection rates by PCR were highest in the population between the ages of 20–60 years of age, there was no statistically significant difference in the seropositivity rates in different age groups. For instance, although the seropositivity rate was highest in the 10–20 age group (34.03%), the PCR positivity rate was 9.80%. Differences in the PCR positivity rates and seropositivity rates were also seen in 60–70-year-olds (8.90 vs. 30.4%) and in individuals >70 years (4.10 vs. 1.20%). The seropositivity rate of the females was 29.70% (290/976), which was significantly higher (p < 0.002) than in males 21.2% (333/1,571).

Conclusions: A high seroprevalence rate (24.5%) was seen in all age groups in the CMC suggesting that a high level of transmission was seen during this time. The higher PCR positivity rates between the ages of 20–60 are likely to be due to increased testing carried out in the working population. Therefore, the PCR positivity rates, appear to underestimate the true extent of the outbreak and the age groups which were infected.

Immune Responses to a Single Dose of the AZD1222/Covishield Vaccine at 16 Weeks in Individuals in Sri Lanka

Due to limited access to vaccines, many countries have only administered a single dose of the AZD1222, whereas the dosage intervals have increased ≥4 wk. We sought to investigate the immunogenicity of a single dose of vaccine at ≥16 wk postimmunization. Severe acute respiratory syndrome coronavirus 2-specific Abs in 553 individuals and Abs to the receptor-binding domain of the Wuhan virus (wild-type) and the variants of concern, angiotensin-converting enzyme 2 receptor blocking Abs ex vivo and cultured IFN-γ T cell (Homo sapiens) responses and B cell (H. sapiens) ELISPOT responses, were investigated in a subcohort. The seropositivity rates in those >70 y of age (93.7%) was not significantly different compared with other age groups (97.7-98.2; Pearson χ² = 7.8; p = 0.05). The Ab titers (Ab index) significantly declined (p < 0.0001) with increase in age. A total of 18 of 69 (26.1%) of individuals did not have angiotensin-converting enzyme 2 receptor-blocking Abs, whereas responses to the receptor-binding domain of wild-type (p = 0.03), B.1.1.7 (p = 0.04), and B.1.617.2 (p = 0.02) were significantly lower in those who were >60 y. Ex vivo IFN-γ T cell ELISPOT responses were seen in 10 of 66 (15.1%), whereas only a few expressed CD107a. However, >85% had a high frequency of cultured IFN-γ T cell ELISPOT responses and B cell ELISPOTs. Virus-specific Abs were maintained at ≥16 wk after receiving a single dose of AZD1222, although levels were lower to variants of concern, especially in older individuals. A single dose induced a high frequency of memory T and B cell responses.

Kinetics of immune responses to the AZD1222/Covishield vaccine with varying dose intervals in Sri Lankan individuals

Background

To understand the kinetics of immune responses with different dosing gaps of the AZD1222 vaccine, we compared antibody and T cell responses in two cohorts with two different dosing gaps.

Methods

Antibodies to the SARS-CoV-2 virus were assessed in 297 individuals with a dosing gap of 12 weeks, sampled at 12 weeks post second dose (cohort 1) and in 77 individuals with a median dosing gap of 21.4 weeks (cohort 2) sampled 6 weeks post second dose. ACE2 receptor blocking antibodies (ACE2R-Abs), antibodies to the receptor binding domain (RBD) of the virus and variants of concern (VOC) and ex vivo T cell responses were assessed in a sub cohort.

Results

All individuals (100%) had SARS-CoV-2 specific total antibodies and 94.2% of cohort 1 and 97.1% of cohort 2 had ACE2R-blocking Abs. There was no difference in antibody titres or positivity rates in different age groups in both cohorts. The ACE2R-blocking Abs (p<0.0001) and antibodies to the RBD of the VOCs were significantly higher in cohort 2, compared to cohort 1. 41.2% to 65.8% of different age groups gave a positive response by the haemagglutination assay to the RBD of the ancestral virus and VOCs in cohort 1, while 53.6% to 90% gave a positive response in cohort 2. 17/57 (29.8%) of cohort 1 and 17/29 (58.6%) of cohort 2 had ex vivo IFNγ ELISpot responses above the positive threshold. The ACE2R-blocking antibodies and ex vivo IFNγ ELISpot responses at 12 weeks post-first dose, significantly correlated with levels 12 weeks post second dose (Spearman's r=0.46, p=0.008) and (Spearman's r=0.71, p<0.0001) respectively.

Conclusions

Both dosing schedules resulted in high levels of antibody and T cell responses post vaccination, although those with a longer dosing gap had a higher magnitude of responses, possibly as immune responses were measured 6 weeks post second dose compared to 12 weeks post second dose.

Persistence of antibody and T cell responses to the Sinopharm/BBIBP-CorV vaccine in Sri Lankan individuals

Background

To determine the kinetics and persistence of immune responses following the Sinopharm/BBIBP-CorV, we investigated immune responses in a cohort of Sri Lankan individuals.

Methods

SARS-CoV-2 specific total antibodies were measured in 20-to-39 year (n=61), 40-to-59-year and those >60 years of age (n=22) by ELISA, 12 weeks after the second dose of the vaccine. ACE2 receptor blocking antibodies (ACE2R-Ab), antibodies to the receptor binding domain (RBD) of the ancestral virus (WT) and variants of concern, were measured in a sub cohort. T cell responses and memory B cell responses were assessed by ELISpot assays.

Results

193/203 (95.07%) of individuals had detectable SARS-CoV-2 specific total antibodies, while 67/110 (60.9%) had ACE2R-Ab. 14.3% to 16.7% individuals in the 20 to 39 age groups had detectable antibodies to the RBD of the WT and VOC, while the positivity rates of those >60 years of age was <10%. 14/49 (28.6%) had IFN _γ ELISpot responses to overlapping peptides of the spike protein, while memory B cell responses were detected in 9/20 to the S1 recombinant protein. The total antibody levels and ACE2R-Ab declined after 2 to 12 weeks from the second dose, while ex vivo T cell responses remained unchanged. The decline in ACE2R-Ab levels was significant among the 40 to 59 (p=0.0007) and ≥60 (p=0.005) age groups.

Conclusions

Antibody responses declined in all age groups, especially in those >60 years, while T cell responses persisted. The effect of waning of immunity on hospitalization and severe disease should be assessed by long term efficacy studies.

723 Neuroendoscopy versus Craniotomy in Basal Ganglia Haemorrhage: A Systematic Review and Meta-Analysis

Aim

Basal ganglia haemorrhage (BGH) is the most common type of intracerebral bleed with high morbidity and mortality rate. The efficacy between craniotomy and endoscopic approach in BGH is still debatable and advancement in minimally invasive technique has made endoscopic approach the preferred option. The aim of this systematic review and meta-analysis was to evaluate the outcomes of craniotomy and endoscopic approach in BGH.

Method

Databases of PubMed, EMBASE, MEDLINE and CENTRAL were systematically searched from its inception until December 2020. All randomized clinical trials and observational studies comparing craniotomy versus endoscopic approach in BGH were included.

Results

Twelve studies enrolling 1297 patients (craniotomy:675, endoscopy:632) were included for qualitative and quantitative analysis. Endoscopic approach was associated with significantly lower postoperative mortality (OR:0.35, P &lt; 0.00001), higher haematoma evacuation rate (MD:4.95, P = 0.0002), shorter operative time (MD:-117.03, P &lt; 0.00001), lesser intraoperative blood loss (MD:-328.47, P &lt; 0.00001), higher postoperative Glasgow Coma Scale (GCS) (MD:1.14, P = 0.01), higher postoperative Glasgow Outcome Scale (GOS) (MD:0.44, P = 0.05), shorter length of hospital stay (MD:-2.90, P &lt; 0.00001), lower complication rate (OR:0.30, P = 0.0004), lower infection rate (OR:0.29, P &lt; 0.00001) and lower modified Rankin Scale (mRS) (MD:-0.57, P = 0.004) compared to craniotomy. No significant difference was detected in reoperation, intracranial infection, re-bleeding.

Conclusions

The best available evidence suggest that endoscopic approach has better outcomes in mortality rate, operative time, haematoma evacuation rate, intraoperative blood loss, length of hospital stay, mRS, postoperative GCS and GOS compared with craniotomy in the management of BGH. However, there is a need for high quality randomised controlled trials with large sample size for definite conclusions.

727 Robotic Assisted Versus Fluoroscopic Guided Approach in Pedicle Screw Insertion: A Systematic Review and Meta-Analysis

Aim

The robotic assisted surgery has become prevalent in most of the surgical subspecialty. The adaption of such technique in spine surgery has resulted in minimising several issues encountered with fluoroscopic guided approach. The aim of this study is to compare the outcomes of robotic assisted approach and fluoroscopic guided approach in pedicle screw insertion.

Method

PUBMED, EMBASE, MEDLINE and CENTRAL database were systematically searched from its inception until November 2020. All the studies comparing robotic assisted surgery and fluoroscopic guided approach in pedicle screw insertion were included for quantitative and qualitative analysis.

Results

Twenty-eight studies enrolling 2105 patients (robotic group: 1027, fluoroscopic: 1078) and total screws of 8668 screws (robotic group: 4217, fluoroscopic group: 4451) were eligible for inclusion, these studies consisted of 19 observational studies, 7 randomised controlled trials (RCTs) and 2 cadaveric study. Robotic assisted approach was associated with significantly higher accuracy (Grade A+B) (OR = 2.34; P &lt; 0.0001) and distance between pedicle and screw (MD: 1.69; P = 0.001), lower incident of facet joint violation (OR = 0.22; P &lt; 0.00001), screw revision (OR = 0.38; P = 0.009), intraoperative blood loss (MD: -116.95; P = 0.0006), shorter pedicle screw placement time (MD: -4.66; P &lt; 0.00001), radiation exposure time (MD:-5.27; P = 0.0001), radiation dose (MD:-22.30; P = 0.0002) and postoperative hospital stay (MD: -0.79; P = 0.02) compared to fluoroscopic guided approach. There was no significant difference in operative time and wound infection.

Conclusions

In this meta-analysis, robotic assisted approach is more effective in achieving better clinical outcomes compared to fluoroscopic guided technique in pedicle screw insertion. However, future adequately powered RCTs are warranted to generate standardised outcomes.

724 Quadriceps Tendon Autograft Versus Hamstring Tendon Autograft in Anterior Cruciate Ligament Repair: A Systematic Review and Meta-Analysis

Aim

Quadriceps tendon (QT) autograft has recently become the popular choice of autograft in anterior cruciate ligament reconstruction (ACLR) and slowly replacing hamstring tendon (HT) autograft. QT autograft has traditionally served as the alternative of HT autograft, but recent studies revealed that QT autografts are not inferior to HT autografts. The purpose of this study was to provide an in-depth review the clinical and functional outcomes between QT and HT autografts in ACLR.

Method

Databases of Pubmed, EMBASE, MEDLINE and CENTRAL were systematically searched from its inception until November 2020. All observational studies comparing QT and HT autografts in the ACRL surgery were included.

Results

Twenty-two observational studies (3 randomized controlled trials and 19 comparative studies) comprising of 16952 patients (QT = 1407, HT = 15545) were included in quantitative meta-analysis. In comparison to HT autograft, patients who received QT autograft had similar postoperative Lysholm Score (MD:1.05, p = 0.44), Tegner Score (MD:0.11, p = 0.06), IKDC score (MD:0.48, p = 0.48), side to side laxity(MD:-0.08, p = 0.77), limb symmetry index (MD:1.87, p = 0.61), Pivot shift test grade 0 (OR:1.13, p = 0.74), Lachman test grade 0 (OR:2.38, p = 0.32), hamstring to quadriceps ratio (MD:-1.10, p = 0.82), incidence of graft failure (OR:0.68, p = 0.43), contralateral knee injury (OR:1.22, p = 0.61), peak torque muscle strength flexion (MD:-0.20, ρ = 0.10) and Cincinnati score (MD:-0.85, p = 0.66).

Conclusions

In this meta-analysis, the usage of QT autograft is not inferior to HT autograft in ACLR. Our study demonstrated comparable morbidity, clinical and functional outcome in QT and HT autografts, indicating that QT autograft is equally safe as HT autograft.

730 Is The Total Hip Arthroplasty For Hip Fracture Comparable With Matched Elective Cohort ? A Prospective Study

Aim

Total hip replacement (THR) has been effective in managing osteoarthritis but its effectiveness in managing neck of femur fracture (#NOF) is debatable due to higher risk of morbidity and mortality. We aimed to review the selection criteria for trauma THR and to compare the functional outcomes and complication profiles of trauma THR cohort with elective THR cohorts.

Method

we prospectively reviewed patients undergoing THR for #NOF with follow-up. The functional outcomes, any further complications-related admissions and death within a year were noted for subsequent analysis. All the patients and data collected were subsequently matched with the elective cohort.

Results

Forty-one matched cases were included in our study. The Modified Harris Hip Score (mHHS) was significantly lower pre-operatively in elective cohort (41.4±14.3 VS 60.3±22.2, P &lt; 0.001) and achieved significantly higher score than trauma cohort 1-year post operatively (88.2±10.9 VS 82.6±12.7, P = 0.029). As for the mHHS Function, the trauma cohort achieved similar value with the pre-operative score post-operatively, and no significant difference was witnessed between the trauma and elective cohort post-operatively (35.1±7.4 VS 37.6±7.7, P = 0.142). mHHS Pain score was significantly higher in trauma cohort pre-operatively (19.8±15.3 VS 12.7±6.3, P = 0.034), but the score was significantly higher than trauma cohort 1-year postoperatively (42.7±4.4 VS 40.7±7.7, P = 0.027). Both cohorts had similar complication rate.

Conclusions

Our study further justified the clinical indication of THR for #NOF. With careful selection, trauma THR can achieve similar HHS function and better pain score. Further randomized controlled trials are warranted to justify our findings.

Bioefficacy of mosquito mat vaporizers and associated metabolic detoxication mechanisms in Aedes aegypti (Linnaeus) in Selangor, Malaysia: A statewide assessment

This study aims to examine the efficacy of mosquito mat vaporizers on Aedes aegypti and their associated metabolic detoxication mechanisms. For this purpose, Aedes aegypti (Linnaeus) was collected from nine districts in Selangor, Malaysia and tested with mosquito vaporizing mat bioassays. The same populations were also subjected to biochemical assays to investigate activities of detoxifying enzymes, namely non-specific esterase (EST), glutathione-S-transferase (GST) and mixed function oxidase (MFO). The efficacy of Ae. aegypti on the active ingredients tested in decreasing order were d- allethrin > dimefluthrin > prallethrin with PBO > prallethrin. The results further indicated significant enhancement mean levels of EST, GST and MFO in pyrethroid-resistant populations. The mortality rate of Ae. aegypti in response to pyrethroid active ingredients was associated with MFO activity, suggesting it is an important detoxification enzyme for the populations tested. In view of the presence of resistance against household insecticide products, pyrethroid efficacy on Ae. aegypti populations needs to be monitored closely to ensure the implementation of an effective vector control program in Malaysia.

Inclusion of cGAMP within virus-like particle vaccines enhances their immunogenicity

Cyclic GMP-AMP (cGAMP) is an immunostimulatory molecule produced by cGAS that activates STING. cGAMP is an adjuvant when administered alongside antigens. cGAMP is also incorporated into enveloped virus particles during budding. Here, we investigate whether inclusion of cGAMP within viral vaccine vectors enhances their immunogenicity. We immunise mice with virus-like particles (VLPs) containing HIV-1 Gag and the vesicular stomatitis virus envelope glycoprotein G (VSV-G). cGAMP loading of VLPs augments CD4 and CD8 T-cell responses. It also increases VLP- and VSV-G-specific antibody titres in a STING-dependent manner and enhances virus neutralisation, accompanied by increased numbers of T follicular helper cells. Vaccination with cGAMP-loaded VLPs containing haemagglutinin induces high titres of influenza A virus neutralising antibodies and confers protection upon virus challenge. This requires cGAMP inclusion within VLPs and is achieved at markedly reduced cGAMP doses. Similarly, cGAMP loading of VLPs containing the SARS-CoV-2 Spike protein enhances Spike-specific antibody titres. cGAMP-loaded VLPs are thus an attractive platform for vaccination.

Serological survey of canine vector-borne diseases in two animal shelters in central Peninsular Malaysia

Canine vector-borne diseases (CVBDs) are increasingly becoming a cause for global concern because of their high morbidity and mortality rates in dogs. However, information on their occurrence in Malaysia is still scanty. In this study, a total of 103 dog blood samples were collected from two animal shelters in central Peninsular Malaysia and tested for the antibodies against Ehrlichia spp., Anaplasma spp., Borrelia burgdorferi, and the antigen of Dirofilaria immitis. Of the 103 tested dogs, 44.7% (46) were found to be seropositive for Ehrlichia spp., 30.1% (31) for Anaplasma spp. and 13.6% (14) for D. immitis. Co-infections of Anaplasma spp. + Ehrlichia spp. (18.5%, 19) were most prevalent, followed by Anaplasma spp. + D. immitis (1.9%; two) and D. immitis + Ehrlichia spp. (1.0%; one). Furthermore, three dogs (2.9%) were also found to have triple infection, testing seropositive for Ehrlichia spp., Anaplasma spp. and D. immitis. The dogs which were found to be seropositive with at least one pathogen were 66.7% (32/51) at shelter A, and 55.8% (29/52) at shelter B. Serological evidence showed that the exposure of major vector-borne diseases in dogs in shelters was relatively high in the surveyed areas. Routine detection and control of vector-borne diseases are of paramount importance for reducing the risk of CVBDs transmission in dogs and humans.

Observations of scrotal mass, liver mass, haemolytic jaundice, and central vestibular disorder in Brugia pahangi-infected dogs

Brugia pahangi is known to infect humans and dogs. Its associated symptoms and complications, however, have not been fully understood in dogs. Herein, we reported the observations of B. pahangi infections in dogs with scrotal mass, liver mass, haemolytic jaundice, and central vestibular disorder.

Nematode control failure due to anthelmintic resistance in a sheep farm in Malaysia: First identification of the F200Y mutation in the isotype 1 β-tubulin gene

This paper reports total nematode anthelmintic resistance towards albendazole, fenbendazole, levamisole and ivermectin in a commercial sheep farm located in Terengganu, Malaysia. Faecal Egg Count Reduction Test (FECRT) was conducted on 25 sheep, where five sheep in each group were treated with the respective four anthelmintics based on live bodyweight. The balance of five sheep placed in the control group were not treated with any anthelmintics. At day 13 post-treatment, faecal egg count was conducted and nematode worm egg count reduction percentage was calculated to determine the resistance status towards the respective anthelmintics tested. Results showed that nematodes were resistant to all the anthelmintics tested, namely albendazole, fenbendazole, levamisole and ivermectin with reduction percentage of 87%, 46%, 94% and 68%, respectively. Subsequently, the third stage larvae of Haemonchus contortus and Trichostrongylus colubriformis recovered from post-treatment faecal cultures were subjected to allele-specific polymerase chain reaction (AS-PCR) assay to determine the presence of the benzimidazole resistance gene. This study reports the occurrence of the classical F200Y mutation in the isotype 1 βtubulin gene, for the first time in Malaysia.

Occurrence of gastro-intestinal parasites among small ruminants in Malaysia: highlighting Dicrocoelium infection in goats

The aim of the present study was to determine the gastro-intestinal (GI) parasitic infections among small ruminants (i.e., goats, sheep, deer) in Malaysia through formalin-ether concentration technique. Overall, 70.9% or 302 out of 426 small ruminants (79.4% or 251/316 goats; 87.5% or 35/40 sheep; 22.9% or 16/70 deer) were infected with at least one species of GI parasites. Overall, ten types of GI parasites [Helminth: strongyle (57.7%), Moniezia spp. (5.4%), Paramphistomum spp. (4.5%), Strongyloides spp. (4.2%), Dicrocoelium spp. (2.3%), Trichuris spp. (2.3%); Protozoa: Eimeria spp. (23.7%), Entamoeba spp. (18.8%), Giardia spp. (1.9%), Cryptosporidium spp. (0.2%)] were detected in this study. Among the studied animals, goats harboured the highest diversity of GI parasites (ten types), followed by sheep (six types) and deer (two types). Polyparasitism was observed in goats (43.7% or 138 of 316) and sheep (15.0% or 6 of 40). Cumulatively, a total of 32 combinations of coinfections (Helminth+Helminth: 8 combinations; Helminth+Protozoa: 20 combinations; Protozoa+Protozoa: 4 combinations) between detected parasites with up to quintuple infections were reported. Among these parasites, "strongyle + Eimeria spp." and "Moniezia spp. + strongyle" were the commonest infections in goats (13.5% or 34 of 251) and sheep (5.7% or 2 of 6), respectively. This study is a comprehensive documentation on multiple GI parasitisms among small ruminant in Malaysia, and the findings are crucial for effective farm management, especially for the formulation of parasitic control and elimination strategies.

First molecular genotyping of A302S mutation in the gamma aminobutyric acid (GABA) receptor in Aedes albopictus from Malaysia

Given the lack of molecular evidence in altered target-site insecticide resistance mechanism in Aedes albopictus (Skuse) worldwide, the present study aims to detect the presence of A302S mutation in the gene encoding the gamma aminobutyric acid receptor resistant to dieldrin (Rdl) in Ae. albopictus for the first time from its native range of South East Asia, namely Malaysia. World Health Organization (WHO) adult susceptibility bioassay indicated a relatively low level of dieldrin resistance (two-fold) in Ae. albopictus from Petaling Jaya, Selangor. However, PCR-RFLP and direct sequencing methods revealed the presence of the A302S mutation with the predomination of heterozygous genotype (40 out of 82 individuals), followed by the resistant genotype with 11 individuals. This study represents the first field evolved instance of A302S mutation in Malaysian insect species.

Mitochondrial DNA analyses reveal low genetic diversity in Culex quinquefasciatus from residential areas in Malaysia

The present study explored the intraspecific genetic diversity, dispersal patterns and phylogeographic relationships of Culex quinquefasciatus Say (Diptera: Culicidae) in Malaysia using reference data available in GenBank in order to reveal this species' phylogenetic relationships. A statistical parsimony network of 70 taxa aligned as 624 characters of the cytochrome c oxidase subunit I (COI) gene and 685 characters of the cytochrome c oxidase subunit II (COII) gene revealed three haplotypes (A1-A3) and four haplotypes (B1-B4), respectively. The concatenated sequences of both COI and COII genes with a total of 1309 characters revealed seven haplotypes (AB1-AB7). Analysis using tcs indicated that haplotype AB1 was the common ancestor and the most widespread haplotype in Malaysia. The genetic distance based on concatenated sequences of both COI and COII genes ranged from 0.00076 to 0.00229. Sequence alignment of Cx. quinquefasciatus from Malaysia and other countries revealed four haplotypes (AA1-AA4) by the COI gene and nine haplotypes (BB1-BB9) by the COII gene. Phylogenetic analyses demonstrated that Malaysian Cx. quinquefasciatus share the same genetic lineage as East African and Asian Cx. quinquefasciatus. This study has inferred the genetic lineages, dispersal patterns and hypothetical ancestral genotypes of Cx. quinquefasciatus.

Co-infection of Haemonchus contortus and Trichostrongylus spp. among livestock in Malaysia as revealed by amplification and sequencing of the internal transcribed spacer II DNA region

Background

Haemonchus contortus and Trichostrongylus spp. are reported to be the most prevalent and highly pathogenic parasites in livestock, particularly in small ruminants. However, the routine conventional tool used in Malaysia could not differentiate the species accurately and therefore limiting the understanding of the co-infections between these two genera among livestock in Malaysia. This study is the first attempt to identify the strongylids of veterinary importance in Malaysia (i.e., H. contortus and Trichostrongylus spp.) by amplification and sequencing of the Internal Transcribed Spacer II DNA region.

Results

Overall, 118 (cattle: 11 of 98 or 11.2%; deer: 4 of 70 or 5.7%; goats: 99 of 157 or 63.1%; swine: 4 of 91 or 4.4%) out of the 416 collected fecal samples were microscopy positive with strongylid infection. The PCR and sequencing results demonstrated that 93 samples (1 or 25.0% of deer; 92 or 92.9% of goats) contained H. contortus. In addition, Trichostrongylus colubriformis was observed in 75 (75.8% of 99) of strongylid infected goats and Trichostrongylus axei in 4 (4.0%) of 99 goats and 2 (50.0%) of 4 deer. Based on the molecular results, co-infection of H. contortus and Trichostrongylus spp. (H. contortus + T. colubriformis denoted as HTC; H. contortus + T. axei denoted as HTA) were only found in goats. Specifically, HTC co-infections have higher rate (71 or 45.2% of 157) compared to HTA co-infections (3 or 1.9% of 157).

Conclusions

The present study is the first molecular identification of strongylid species among livestock in Malaysia which is essential towards a better knowledge of the epidemiology of gastro-intestinal parasitic infection among livestock in the country. Furthermore, a more comprehensive or nationwide molecular-based study on gastro-intestinal parasites in livestock should be carried out in the future, given that molecular tools could assist in improving diagnosis of veterinary parasitology in Malaysia due to its high sensitivity and accuracy.

Isolation and characterization of β-glucosidases from Aspergillus nidulans mutant USDB 1183

Two extracellular β-glucosidases (cellobiase, EC 3.2.1.21), I and II, from Aspergillus nidulans USDB 1183 were purified to homogeneity with molecular weights of 240,000 and 78,000, respectively. Both hydrolysed laminaribiose, β-gentiobiose, cellobiose, p-nitrophenyl-β-L-glucoside, phenyl-β-L-glucoside, o-nitrophenyl-β-L-glucoside, salicin and methyl-β-L-glucoside but not α-linked disaccharides. Both were competitively inhibited by glucose and non-competitively (mixed) inhibited by glucono-1,5-lactone. β-Glucosidase I was more susceptible to inhibition by Ag(+) and less inhibited by Fe(2+) and Fe(3+) than β-glucosidase II.

Sources of fungal linamarases

Forty-four strains of Aspergillus, Penicillium, Fusarium, Trichoderma and Rhizopus were grown on a liquid medium containing glucose and cassava-root extract. All of the Aspergillus and Fusarium strains, eight out of 10 Penicillium strains and three of seven Trichoderma strains showed linamarase activity. No such activity was detected in any Rhizopus strain. The crude enzyme preparation from F. oxysporum had the highest affinity for linamarin whereas that from A. nidulans was the most heat-stable.

First molecular genotyping of voltage gated sodium channel alleles in Culex quinquefasciatus populations in Malaysia

A nationwide investigation was performed to detect the presence of 1014 mutation(s) in voltage gated sodium channel (kdr) gene of Culex quinquefasciatus from 14 residential areas across 13 states and a federal territory in Malaysia. Molecular genotyping of kdr mutation was performed via a modified three tubes allele-specific-polymerase chain reaction (AS-PCR) and direct sequencing of kdr gene. Based on the results of AS-PCR, homozygous susceptible (SS) genotype was found in nine out of 14 populations with 38 individuals from a total sample size of 140. Heterozygous (RS) genotype was most predominant (99 individuals) and distributed across all study sites. Homozygous resistance (RR) genotype was detected in Perak (one individual) and Selangor (two individuals). The resistance kdr allele frequencies ranged from 0.1 to 0.55, with the highest being detected in Cx. quinquefasciatus population from Selangor. This study has documented the first field-evolved instance of 1014F mutation in Malaysian mosquitoes and the findings of this study could be utilized in the implementation of strategic measures in vector control programs in Malaysia.

First molecular characterization of Giardia duodenalis from goats in Malaysia

In the present study, 310 faecal samples from goats from eight different farms in Malaysia were tested for the presence of Giardia using a PCR-coupled approach. The nested PCR for SSU amplified products of the expected size (∼200 bp) from 21 of 310 (6.8%) samples. Sixteen of these 21 products could be sequenced successfully and represented six distinct sequence types. Phylogenetic analysis of the SSU sequence data using Bayesian Inference (BI) identified Giardia assemblages A, B and E. The identification of the 'zoonotic' assemblages A and B suggests that Giardia-infected goats represent a possible reservoir for human giardiasis in Malaysia.

Subdural haematoma due to dural metastases from bronchogenic carcinoma in a previously well patient: an unusual cause of non-traumatic recurrent intracranial haematomata

Subdural haematomata (SDH) are usually traumatic in aetiology. Non-traumatic instances of SDH are uncommon, and can rarely be due to metastases involving the dura. Computed tomography or magnetic resonance imaging can be misleading, as the underlying aetiology may be masked by the SDH, or the appearance can simulate meningiomas. A high index of suspicion for SDH is thus required. Under such circumstances, when no overt cause is identified, dural tissue should be sent for histological analysis and blood clot for cytology, even if the appearances are grossly normal at surgery. We present a rare case of a 42-year-old woman who was previously well, but presented with progressive weakness due to acute spontaneous SDH. She required repeated surgical evacuations for SDH and for subsequent recurrent extradural haematomata. After extensive investigations, the cause was identified to be secondary dural metastases from a primary lung carcinoma.

The anaesthetist's role in the setting up of an intraoperative MR imaging facility

The clinical and economic advantages of intraoperative magnetic resonance (MR) imaging for neurosurgery are apparent. Hence, more medical institutions are setting up such services. Establishing such a service can be daunting because of the cost and specifications, its highly technical nature and many safety considerations. The anaesthetists have an integral part to play during this process because of their stake as key users and their vital role in conducting anaesthesia for complex neurosurgery within this hostile, and sometimes remote, environment. Moreover, their experiences with efficient workflows, patient screening and concern about safety make them eminently qualified members of the planning and building process. They are also no strangers to budgets and equipment appraisals. The complex interactions between conducting anaesthesia in a hostile environment and in a remote site conspire to make this a challenging undertaking. This article describes the role, the practical considerations and the difficulties experienced by the neurosurgical anaesthetists in setting up an intraoperative MR imaging operating theatre at Singapore General Hospital, from planning to equipment procurement and streamlining the workflow. Safety concerns and training are vital aspects of this article. It is hoped that our experiences will be of help to others who will be called upon at some point in a similar undertaking.

How severe acute respiratory syndrome (SARS) affected the department of anaesthesia at Singapore General Hospital

The effects of the outbreak of severe acute respiratory syndrome (SARS) on the Singapore General Hospital's Department of Anaesthesia are described. Urgent measures to protect staff and patients were implemented. Clear direction in administration issues and clinical pathways with good logistic support were essential. Anaesthetists were at risk and anaesthetic practice had to change in view of strict infection control provisions. Contingency planning for future infectious diseases outbreaks is required. Lessons can be learnt by hospitals yet to be visited by this virulent infection.

Groups perform better than the best individuals on letters-to-numbers problems: Informative equations and effective strategies

One-hundred 3-person groups and 300 individuals solved 2 letters-to-numbers problems, requiring identification of the coding of 10 letters to 10 numbers by proposing an equation in letters, receiving the answer in letters, proposing a hypothesis, and receiving feedback on the hypothesis on each trial. There were 5 instruction conditions: (a). standard, (b). use at least 3 letters on all equations, (c). use at least 4 letters on all equations, (d). number 1 known before beginning problem, and (e). number 9 known before beginning problem. The groups had fewer trials to solution, proposed more complex equations, and identified more letters per equation than the best individuals. Performance was best under instructions to use at least 4 letters and with the number 9 known.

Somatosensory evoked potential monitoring during carotid endarterectomy in patients with a stroke

The aim of our study was to assess the characteristics and feasibility of somatosensory evoked potential (SSEP) monitoring in patients who have had a stroke undergoing carotid endarterectomy. We retrospectively reviewed the medical and SSEP records of 204 patients. The patients were divided into two groups: Stroke (n = 65) and No-Stroke (n = 139). The amplitude and latency of the N20-P25 cortical complex on the ipsilateral side (surgical) were compared with the contralateral side in each group and between groups. Stroke patients showed asymmetry of their cortical waveforms; the ipsilateral N20-P25 baseline amplitude was 1.5 +/- 1.0 microv versus 1.9 +/- 1.2 microv for the contralateral (P = 0.001), for No-Stroke patients 2.0 +/- 1.1 microv versus 2.1 +/- 1.1 microv (P = 0.2). Forty-eight percent of Stroke patients had a ratio (ipsilateral/contralateral amplitude) of <1.0 +/- 0.2 compared with 26% for No-Stroke patients (P = 0.01). There were no differences in latency measurements, in the incidences of significant SSEP changes (four Stroke, six No-Stroke) and immediate postoperative neurological deficits (two Stroke, six No-Stroke) between the two groups. Nine patients (three Stroke, six No-Stroke) had a decrease in ipsilateral N20-P25 amplitude >50% after cross-clamping, and had a shunt inserted. In conclusion, patients with a history of a stroke before surgery had a decrease in the amplitude of the ipsilateral cortical peak. There were no differences in the incidences of SSEP changes or neurological deficits.

IMPLICATIONS

Patients who have had a preoperative stroke may show asymmetry of their cortical baseline somatosensory evoked potential waveforms; however, this does not interfere with the ability to use somatosensory evoked potential as a monitor during surgery.

Concurrent production of chitin from shrimp shells and fungi

Crustacean shells constitute the traditional and current commercial source of chitin. Conversely, the control of fungal fermentation processes to produce quality chitin makes fungal mycelia an attractive alternative source. Therefore, the exploitation of both of these sources to produce chitin in a concurrent process should be advantageous and is reported here. Three proteolytic Aspergillus niger (strains 0576, 0307 and 0474) were selected from a screening for protease activity from among 34 zygomycete and deuteromycete strains. When fungi and shrimp shell powder were combined in a single reactor, the release of protease by the fungi facilitated the deproteinization of shrimp-shell powder and the release of hydrolyzed proteins. The hydrolyzed proteins in turn were utilized as a nitrogen source for fungal growth, leading to a lowering of the pH of the fermentation medium, thereby further enhancing the demineralization of the shrimp-shell powder. The shrimp-shell powders and fungal mycelia were separated after fermentation and extracted for chitin with 5% LiCl/DMAc solvent. Chitin isolates from the shells were found to have a protein content of less than 5%, while chitin isolates from the three fungal mycelia strains had protein content in the range of 10-15%. The relative molecular weights as estimated by GPC for all chitin samples were in the 10(5) dalton range. All samples displayed characteristic profiles for chitin in their FTIR and solid-state NMR spectra. All chitin samples evaluated with MTT and Neutral Red assays with three commercial cell lines did not display cytotoxic effects.

Evaluation of the allergenicity of tropical pollen and airborne spores in Singapore

BACKGROUND

Sensitization to pollen and spores of the Southeast Asian tropical region is not well documented. This study evaluated the allergenicity of the tropical airspora in Singapore.

METHODS

On the basis of the results of an aerobiologic survey of the airspora profile of Singapore, crude extracts of 23 main spore (fungal and fern) and pollen types were prepared. A total of 231 patients with asthma and/or allergic rhinitis and 76 healthy controls were evaluated by skin prick test (SPT). Total and specific IgE levels were also quantified by the fluorescence allergosorbent test (FAST).

RESULTS

All 23 allergenic extracts tested elicited positive SPT responses. Among the patients with atopic diseases, extracts of oil-palm pollen (Elaeis guineensis) were observed to have the highest frequency of positive reactions (40%), followed by extracts of resam-fern spores (Dicranopteris linearis) (34%) and sea-teak pollen (Podocarpus polystachyus) (33.8%). Fungal spores with the highest SPT responses were Curvularia spp. (26-32%) and Drechslera-like spores (31%). Positive responses to these extracts correlated with total serum IgE levels of the subjects and were significantly associated with the presence of atopic disease.

CONCLUSIONS

We have documented sensitization to tropical pollen and spores in our population. Its association with atopy suggests that it has a role in allergic diseases in the tropics.

Epidural analgesia in obstetrics

An ideal analgesic for labour would preferably be non-invasive, as effective as spinals and epidurals without their attendant complications and is safe to mother and child and should not complicate the labour process. Analgesia for labouring women ranges from the use of opioid injections to invasive methods, chiefly epidural injections. Each has its advantages and drawbacks. This article provides a review of analgesic methods and techniques for labouring women. It focuses mainly on the role of epidurals, how it is utilised by anaesthetists and the differing methods of drug delivery through the epidural route. It discusses various concoctions of local anaesthetics and adjuvants used. The epidural route is probably the most effective and most commonly used invasive route for achieving analgesia during labour. Local anaesthetics of varying concentrations are administered as intermittent boluses or as a continuous infusion. Adjuvant drugs are able to enhance the quality and duration of the analgesia. Opioids including fentanyl and sufentanil, and clonidine are discussed. The use of patient-controlled epidural analgesia and combined spinal-epidural analgesia are reviewed. Ambulatory or mobile epidurals are increasingly popular. They are known to improve maternal satisfaction because of preservation of motor power. Ambulation may help with cervical dilatation and engagement, and abolition of backpain, among other advantages. This article describes the methods of establishing mobile epidurals and offers guidelines on safe ambulation and contraindications to its use.

Interhospital and intrahospital transfer of the critically ill patient

AIM

This paper highlights hazards involved in moving critically ill patients between locations, discusses minimalisation of risks involved and the advantages of specialist teams.

METHOD

This is a systematic review.

RESULTS AND CONCLUSIONS

Critically ill patients are moved within the hospital because of the need for surgical procedures or to have fixed facilities investigations performed. Interhospital movement of patients is necessary for specialised care available elsewhere. This has increased with centralisation of specialist services. This paper adopts a practical approach to the transfer process. It establishes the goals of conducting a safe transfer, highlights the deleterious effects of moving an ill patient, the risks and pitfalls of a transfer, and how to minimise them. Attention is drawn to the need for proper resuscitation and stabilisation of a patient before transport. The quality and outcome of the transfer depend on the experience of the transferring team and on adequate monitoring facilities. The benefits of a specialist transfer team is suggested.

Allergens of Bipolaris species

Skin prick tests done previously revealed a significantly higher percentage of sensitization to an extract of Bipolaris sp. among atopic individuals (34/147, 23.1%) compared to non-atopic individuals. Bipolaris-specific IgE levels were quantified in sera from a representative group of 38 individuals using the Fluorescence Allergosorbent Test (FAST). Result obtained by FAST were found to be comparable to the skin prick test results (r2 = 0.60, p < 0.001 for IgE levels vs wheal sizes; r2 = 0.44, p < 0.001 for IgE levels vs erythema sizes). Characterisation of the extract's allergenic component by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) showed 28 protein bands with molecular weights (MW) ranging from 11 kDa to above 100 kDa. Immunoblotting with sera of 10 Bipolaris-sensitive (skin prick test, 3 +) individuals showed that Bipolaris spore extract contained at least 4 IgE binding proteins (MW 11-13 kDa, 16-17 kDa, 20-22 kDa and 36 kDa). All 10 sera reacted to the protein at MW 20-22 kDa, 2 sera with MW 11-13 kDa, 3 sera with 16-17 kDa and 6 sera with 36 kDa. This study has thus demonstrated that spores of Bipolaris sp. contain allergenic components which may elicit IgE-mediated reactions.

House dust mite allergen levels in a Singapore hospital

House dust mite allergens constitute one of the most important allergens in house dust. In this study, the levels of two common dust mite allergens, Der p I and Der f I, in a general hospital in Singapore were evaluated. Our results showed that these allergens were detected in 42/74 (or 57%) of the dust samples. Der p I was found to be the predominant allergen detected (p < 0.001). The allergen levels were, however, low with only 1/74 having a Der p I concentration above 2 micrograms g-1 dust. None of the samples had Der f I concentrations above this level. Of the various niches studied (mattresses, pillows, sofas, carpets, blinds and floors), the blinds and floors had the lowest concentration of allergen (p < 0.05). These low levels in the hospital compared to homes were attributed to the vigorous cleaning schedule in the hospital, the use of plastic to encased mattresses and pillows, vinyl covered sofas and vinyl lined floors. These practices may be adopted in the home as a means to reduce mite allergen exposure.

General anaesthesia vs sedation for minor gynaecological procedures--a comparative study

Sedation using combined intravenous midazolam and fentanyl is a popular technique for minor gynaecological procedures. However, it is fraught with inconsistency in efficacy and has a greater tendency to perioperative oxygen desaturation. Fifty female ASA I patients scheduled for minor gynaecological procedures were given intravenous midazolam and fentanyl before surgery started. Intraoperative excessive movement that interfered with surgery and failure to maintain a patient airway were noted. Perioperative oxygen saturation was monitored with the pulse oximeter. In another group of 50 female ASA I patients, intravenous thiopentone was given and anaesthesia maintained with 67% nitrous oxide in 33% oxygen and 0.5% of isoflurane via a face mask. Results showed that 10% of the sedated patients had excessive movements that interfered with surgery, of which 6% needed a general anaesthetic. Twenty-two percent of the sedated patients needed maintenance of airway perioperatively. Perioperative oxygen desaturation was profound in incidence and degree in the sedated patients whereas no patient who received general anaesthesia desaturated. The perioperative incidence of desaturation in the sedated patients was 46%. Intraoperatively, 28% (p < 0.001) of the sedated patients had oxygen saturation in the range of 85 to 90% and 18% of them (p < 0.01) had oxygen saturation of less than 85%. Postoperatively 8% of the sedated patients had oxygen saturation of 85 to 90%. We conclude that general anaesthesia is more efficacious and safer than sedation in patients scheduled for minor gynaecological procedures. The same minimum standard of monitoring applied to general anaesthesia should be used for sedated patients.

Dysphagia and chronic schizophrenia: a case report

It is known that dysphagia in schizophrenia could result from acute or tardive dystonic reactions or parkinsonism as a result of neuroleptics. This case illustrates that dysphagia may be inherent in schizophrenia itself and not necessarily be due to neuroleptics.

Cancer: To tell or not to tell?

After a patient is diagnosed with a malignant illness, the physician is often left with the dilemma of how to communicate the diagnosis to the patient and the family. In the West, it is often the consensus that the patient be told. This is not necessarily true elsewhere, eg in Japan, the patient is often not told. A questionnaire survey was done to study how Singapore doctors feel about revealing the diagnosis of cancer to the patient. 90.4% of respondents will reveal the diagnosis to the family, while only 43.6% will inform the patient. The possible reasons are discussed.

Protoplast fusion of beta-glucosidase-producing Aspergillus niger strains

Protoplast fusion, induced by polyethylene glycol and Ca2+, was carried out between two auxotrophic strains of Aspergillus niger. The fusion frequency ranged from 6.2 x 10(-2) - 9.1 x 10(-2). After induced haploidization of a diploid, various segregants showing combinations of the parental genetic markers were isolated. Unlike diploids, haploid segregants exhibited greater variations in their morphology and beta-glucosidase activities. One segregant showed a 2.5-fold increase in beta-glucosidase activity over those of the parents. Thus, this method appears promising for creating new recombinant strains of A. niger with improved beta-glucosidase activities.