Microbially induced calcite precipitation performance of multiple landfill indigenous bacteria compared to a commercially available bacteria in porous media.

Microbially Induced Carbonate Precipitation (MICP) is currently viewed as one of the potential prominent processes for field applications towards the prevention of soil erosion, healing cracks in bricks, and groundwater contamination. Typically, the bacteria involved in MICP manipulate their environment leading to calcite precipitation with an enzyme such as urease, causing calcite crystals to form on the surface of grains forming cementation bonds between particles that help in reducing soil permeability and increase overall compressive strength. In this paper, the main focus is to study the MICP performance of three indigenous landfill bacteria against a well-known commercially bought MICP bacteria (Bacillus megaterium) using sand columns. In order to check the viability of the method for potential field conditions, the tests were carried out at slightly less favourable environmental conditions, i.e., at temperatures between 15-17°C and without the addition of urease enzymes. Furthermore, the sand was loose without any compaction to imitate real ground conditions. The results showed that the indigenous bacteria yielded similar permeability reduction (4.79 E-05 to 5.65 E-05) and calcium carbonate formation (14.4-14.7%) to the control bacteria (Bacillus megaterium), which had permeability reduction of 4.56 E-5 and CaCO3 of 13.6%. Also, reasonably good unconfined compressive strengths (160-258 kPa) were noted for the indigenous bacteria samples (160 kPa). SEM and XRD showed the variation of biocrystals formation mainly detected as Calcite and Vaterite. Overall, all of the indigenous bacteria performed slightly better than the control bacteria in strength, permeability, and CaCO3 precipitation. In retrospect, this study provides clear evidence that the indigenous bacteria in such environments can provide similar calcite precipitation potential as well-documented bacteria from cell culture banks. Hence, the idea of MICP field application through biostimulation of indigenous bacteria rather than bioaugmentation can become a reality in the near future.

MICP as a potential sustainable technique to treat or entrap contaminants in the natural environment: A review.

In the last two decades, developments in the area of biomineralization has yielded promising results making it a potentially environmentally friendly technique for a wide range of applications in engineering and wastewater/heavy metal remediation. Microbially Induced Carbonate Precipitation (MICP) has led to numerous patented applications ranging from novel strains and nutrient sources for the precipitation of biominerals. Studies are being constantly published to optimize the process to become a promising, cost effective, ecofriendly approach when compared with the existing traditional remediation technologies which are implemented to solve multiple contamination/pollution issues. Heavy metal pollution still poses a major threat towards compromising the ecosystem. The removal of heavy metals is of high importance due to their recalcitrance and persistence in the environment. In that perspective, this paper reviews the current and most significant discoveries and applications of MICP towards the conversion of heavy metals into heavy metal carbonates and removal of calcium from contaminated media such as polluted water. It is evident from the literature survey that although heavy metal carbonate research is very effective in removal, is still in its early stages but could serve as a solution if the microorganisms are stimulated directly in the heavy metal environment.

Towards total voluntary non-remunerated blood donation in Trinidad and Tobago

Objective: Investigate the historical origins of voluntary nonremunerated blood donation (VNRD) and describe a UWI-led initiative. Design and Methodology: Historical review was performed using internet searches, documents, books, journals, interviews. Data from blood donor cards and Microsoft Excel spreadsheets was collected prospectively and analysed retrospectively. Donors were classified by age, gender, donation status (first-time or repeat) and donation outcome (accepted or deferred). The prevalence of transfusion transmissible infections and deferrals in donors was compared to the national donor pool using Chi square analysis to compare proportions and a p value < 0.05 to assign statistical significance. Results: Human to human blood transfusion and voluntary non-remunerated blood donation were first practised in metropolitan countries and amplified in large scale community blood donation programmes during World War II. Blood donation systems based on individual, transactional donations emerged in most developing countries, including Trinidad and Tobago, causing low donation rates, chronic blood shortage, unequal access, high donor infections and high donor deferrals. A voluntary non-remunerated blood donation programme started by the UWI Blood Donor Foundation and the North Central Health Authority has collected 660 units of blood in its first three years, the majority from persons aged 16 -25 age (52%), females (52%) and repeat donors (51%). Deferrals were < 10% and total transfusion transmissible infections in donors 0.9% compared with 43.6% and 2.4 % respectively (p < 0.05 for both) for the involuntary national donor pool. Conclusion: This model could be extended to all blood donation centres and the community to achieve 100% VNRD.

Biomineralisation performance of bacteria isolated from a landfill in China.

We report an investigation of microbially induced carbonate precipitation by seven indigenous bacteria isolated from a landfill in China. Bacterial strains were cultured in a medium supplemented with 25 mmol/L calcium chloride and 333 mmol/L urea. The experiments were carried out at 30 °C for 7 days with agitation by a shaking table at 130 r/min. Scanning electron microscopic and X-ray diffraction analyses showed variations in calcium carbonate polymorphs and mineral composition induced by all bacterial strains. The amount of carbonate precipitation was quantified by titration. The amount of carbonate precipitated in the medium varied among isolates, with the lowest being Bacillus aerius rawirorabr15 (LC092833) precipitating around 1.5 times more carbonate per unit volume than the abiotic (blank) solution. Pseudomonas nitroreducens szh_asesj15 (LC090854) was found to be the most efficient, precipitating 3.2 times more carbonate than the abiotic solution. Our results indicate that bacterial carbonate precipitation occurred through ureolysis and suggest that variations in carbonate crystal polymorphs and rates of precipitation were driven by strain-specific differences in urease expression and response to the alkaline environment. These results and the method applied provide benchmarking and screening data for assessing the bioremediation potential of indigenous bacteria for containment of contaminants in landfills.

Blood utilisation in a developing society: what is the best index of efficiency?

OBJECTIVES: To assess blood usage for elective surgery in a developing country as a first step towards developing a maximum surgical blood-ordering schedule (MSBOS). BACKGROUND: Cross-match:transfusion (C/T) ratio, transfusion index (Ti ) and transfusion ratio (T%) are standard indices of efficient blood usage for elective surgical procedures. The MSBOS assigns surgical procedures to Group and Cross Match (GXM) and Group and Save (G&S) categories. Non-use probability (NUP) is the percentage of blood that is requested but not used. Trinidad and Tobago (TTO) has a transfusion service that predominantly uses family replacement (F/R) donors. MATERIALS/METHODS: C/T ratio, Ti , T% and NUP were retrospectively calculated for 304 elective surgical procedures performed at a tertiary medical institution in TTO between 1st January and 15th May 2013. RESULTS: For 17 types of surgical procedure, C/T ratio was <2·5 for 10, T% ≥ 30 for 10 and Ti ≥ 0·5 for 12, suggesting efficiency, significant blood use and a requirement for GXM for most operations. However, the majority of these procedures qualify for G&S when performed under conditions that guarantee ready access to blood in an emergency. A substantial proportion of issued blood was returned unused to the blood bank, giving an NUP of 39·7%. CONCLUSION: NUP was the most sensitive measure of efficiency. C/T ratio, T% and Ti must be interpreted in the context of the blood donation system. An internationally accepted value of NUP that equates to efficient blood use should be adopted.

Next-generation sequencing showing potential leachate influence on bacterial communities around a landfill in China.

The impact of contaminated leachate on groundwater from landfills is well known, but the specific effects on bacterial consortia are less well-studied. Bacterial communities in a landfill and an urban site located in Suzhou, China, were studied using Illumina high-throughput sequencing. A total of 153 944 good-quality reads were produced and sequences assigned to 6388 operational taxonomic units. Bacterial consortia consisted of up to 16 phyla, including Proteobacteria (31.9%-94.9% at landfill, 25.1%-43.3% at urban sites), Actinobacteria (0%-28.7% at landfill, 9.9%-34.3% at urban sites), Bacteroidetes (1.4%-25.6% at landfill, 5.6%-7.8% at urban sites), Chloroflexi (0.4%-26.5% at urban sites only), and unclassified bacteria. Pseudomonas was the dominant (67%-93%) genus in landfill leachate. Arsenic concentrations in landfill raw leachate (RL) (1.11 × 103 µg/L) and fresh leachate (FL2) (1.78 × 103 µg/L) and mercury concentrations in RL (10.9 µg/L) and FL2 (7.37 µg/L) exceeded Chinese State Environmental Protection Administration standards for leachate in landfills. The Shannon diversity index and Chao1 richness estimate showed RL and FL2 lacked richness and diversity when compared with other samples. This is consistent with stresses imposed by elevated arsenic and mercury and has implications for ecological site remediation by bioremediation or natural attenuation.

Blood donors' attitudes towards voluntary non-remunerated donation in Trinidad and Tobago.

OBJECTIVES: To assess the attitude towards voluntary non-remunerated blood donation among blood donors in Trinidad and Tobago (TRT). BACKGROUND: Blood donors in TRT are either family replacement (F/R, 87%) or remunerated (13%). There is chronic blood shortage and high seroreactivity for transfusion-transmissible infections (TTI) in donors. Converting existing to voluntary non-remunerated donors (VNRD) reduces the need to recruit news donors in achieving 100% VNRD. METHODS: A questionnaire-based, cross-sectional survey was conducted at two blood collection centres at an interval of 8 years. Donors were surveyed for sociodemographic characteristics, awareness of the blood shortage, previous donation behaviour, donor-beneficiary linkage if F/R, willingness to become VNRD and choice of motivators for converting to VNRD. RESULTS: A total of 400 and 595 donors respectively participated in Surveys 1 and 2, of whom 92·8 and 86·3% were F/R (P < 0·001), respectively. In both surveys, 52% of participants were unaware of an existing blood shortage (P = 0·983). Only 9·8 and 9·1% of participants expressed unwillingness to become VNRD (P = 0·720). The main motivators to convert to VNRD were reminders from the centre (84%) and extended opening hours (78%) in Survey 1 as compared to confidence that donated blood was used properly (73%) and shortened waiting times to donate (73%) in Survey 2. CONCLUSION: Despite low awareness of blood shortage, willingness to become VNRD was high among existing donors. Accountability and donor convenience underpinned the main motivators for converting to VNRD.

Blood transfusion in the Caribbean: a case study of Trinidad and Tobago.

The Caribbean islands form an archipelago connecting North and South America. They have all been colonised by European countries and share strong historical, social, economic and diplomatic links with North America. However, their blood transfusion services have evolved differently, using predominantly family/replacement rather than voluntary non-remunerated donors as has been the practice in England and America since 1926 and 1970, respectively. This article uses the case of Trinidad and Tobago to examine the history and current state of blood transfusion services in the Caribbean and to present early results of an initiative for improving blood safety and adequacy in the region.

Development and characteristics of polymer monoliths for advanced LC bioscreening applications: A review.

Biomedical research advances over the past two decades in bioseparation science and engineering have led to the development of new adsorbent systems called monoliths, mostly as stationary supports for liquid chromatography (LC) applications. They are acknowledged to offer better mass transfer hydrodynamics than their particulate counterparts. Also, their architectural and morphological traits can be tailored in situ to meet the hydrodynamic size of molecules which include proteins, pDNA, cells and viral targets. This has enabled their development for a plethora of enhanced bioscreening applications including biosensing, biomolecular purification, concentration and separation, achieved through the introduction of specific functional moieties or ligands (such as triethylamine, N,N-dimethyl-N-dodecylamine, antibodies, enzymes and aptamers) into the molecular architecture of monoliths. Notwithstanding, the application of monoliths presents major material and bioprocess challenges. The relationship between in-process polymerisation characteristics and the physicochemical properties of monolith is critical to optimise chromatographic performance. There is also a need to develop theoretical models for non-invasive analyses and predictions. This review article therefore discusses in-process analytical conditions, functionalisation chemistries and ligands relevant to establish the characteristics of monoliths in order to facilitate a wide range of enhanced bioscreening applications. It gives emphasis to the development of functional polymethacrylate monoliths for microfluidic and preparative scale bio-applications.

Deploying aptameric sensing technology for rapid pandemic monitoring.

The genome of virulent strains may possess the ability to mutate by means of antigenic shift and/or antigenic drift as well as being resistant to antibiotics with time. The outbreak and spread of these virulent diseases including avian influenza (H1N1), severe acute respiratory syndrome (SARS-Corona virus), cholera (Vibrio cholera), tuberculosis (Mycobacterium tuberculosis), Ebola hemorrhagic fever (Ebola Virus) and AIDS (HIV-1) necessitate urgent attention to develop diagnostic protocols and assays for rapid detection and screening. Rapid and accurate detection of first cases with certainty will contribute significantly in preventing disease transmission and escalation to pandemic levels. As a result, there is a need to develop technologies that can meet the heavy demand of an all-embedded, inexpensive, specific and fast biosensing for the detection and screening of pathogens in active or latent forms to offer quick diagnosis and early treatments in order to avoid disease aggravation and unnecessary late treatment costs. Nucleic acid aptamers are short, single-stranded RNA or DNA sequences that can selectively bind to specific cellular and biomolecular targets. Aptamers, as new-age bioaffinity probes, have the necessary biophysical characteristics for improved pathogen detection. This article seeks to review global pandemic situations in relation to advances in pathogen detection systems. It particularly discusses aptameric biosensing and establishes application opportunities for effective pandemic monitoring. Insights into the application of continuous polymeric supports as the synthetic base for aptamer coupling to provide the needed convective mass transport for rapid screening is also presented.

Ophthalmic manifestations of haematological disorders.

Five case histories are presented. Waldenstrom's macroglobulinaemia caused bilateral central retinal vein occlusion, proptosis was the presenting feature of retro-orbital plasmacytoma in relapsed multiple myeloma, a red painful eye was due to neovascular glaucoma in primary polycythaemia, bilateral VIth nerve palsy caused convergent squint and diplopia in meningeal relapse of acute lymphoblastic leukaemia and lymphoma of the eyelid caused complete ptosis. Interdisciplinary management is described. Ophthalmological lesions in haematological disease should be promptly recognized and managed. Collaboration between ophthalmology and haematology departments may be effective for palliative management.

Five-year follow-up of patients treated with imatinib mesylate for chronic myeloid leukaemia in Trinidad and Tobago.

OBJECTIVE: Data on the use of Imatinib (IM) in developing countries remain limited. A retrospective study was done to assess the efficacy and toxicity of IM in treating chronic myeloid leukaemia (CML) in Trinidad and Tobago. METHODS: Patients in all phases of CML who started IM therapy between February 2001 and February 2004 were included. All had received other previous therapy. They were assessed for haematological, cytogenetic and molecular response, overall survival (OS), event free survival (EFS) and adverse effects (AE). RESULTS: Twenty-five patients were followed-up for a median 61 months. At initiation of IM, 18 were in the chronic phase (CP), 3 in accelerated phase (AP), 3 in blast crisis (BC) and one in myelofibrotic transformation (MF). Overall, 96% of patients achieved complete haematological remission (CHR). Among CP patients, 67% attained a major cytogenetic response (MCR) and 44% a complete cytogenetic response (CCR). Overall survival and event free survival in the CP group were 82% and 76% respectively. Overall survival for advanced phase patients was 14% at 61 months. The adverse effects of IM were the same as previously described and generally tolerable. No patient opted to discontinue IM because of side effects. CONCLUSION: After 5 years of follow-up, IM was found to induce favourable and durable survival responses with an acceptable side effect profile in CP-CML patients who had received prior treatment with alternative agents.

Evaluation of blood donor deferral causes in the Trinidad and Tobago National Blood Transfusion Service.

The majority of blood donations in Trinidad and Tobago are made as replacement by family members or friends. National Blood Transfusion Policy was drafted in 2007 to promote voluntary, repeated donation. The objective of this study is to assess the current rate and reasons for donor deferral, and the aim is to guide the proposed donor education and recruitment programme. A retrospective study of pre-donation deferral of prospective blood donors at the National Blood Transfusion Centre, Port of Spain, Trinidad and Tobago, was conducted. Records of all pre-donation deferrals over a 12-month period were studied. As many as 11,346 pre-donation screening interviews were conducted. There were 4043 (35.6%) deferrals. The most common reasons for donor deferral were exposure to high-risk sexual activity (27.6%), low haemoglobin 22.2% and hypertension 17.5%. Other reasons such as medication, chronic medical illness, tattoos, travel history, recent pregnancy, surgery or presentation outside the accepted age limit caused 33.8% of all deferrals and the majority (34.7%) of male deferrals. Low haemoglobin (44.5%) was the most common reason among females. The rate of deferral of voluntary donors was not significantly different from that for replacement donors (31.7 vs. 35.4%, P = 0.25). This study exposed a lack of public awareness as the principal reason for an unacceptably high rate of donor deferral. Donor education about selection criteria needs to be urgently addressed as an objective of the National Policy. Monitoring and evaluation of deferral rates and reasons could be used as one indicator of the effectiveness of the Policy.

Establishing an oral anticoagulant monitoring service in a multiethnic developing country.

We describe the establishment of an International Normalized Ratio (INR)-based system for monitoring oral anticoagulant therapy in a multiethnic developing country. There was significant variation in geometric mean normal prothrombin time among ethnic groups: 12.7 s for Indians, 13.4 s for Africans and 13.7 s for subjects of mixed ancestry. About 4129 INR measurements were performed in the first 2 years. The majority (55.2%) of achieved INRs were subtherapeutic. We found 31 (0.8%) instances of severe overanticoagulation (INR > 8.0). There were no bleeding manifestations in 24 (77%) of them. Only two experienced life-threatening haemorrhage. The management of bleeding and excessive anticoagulation was not always in accordance with international recommendations. The high incidence of underanticoagulation in Trinidad and Tobago may be due to genetically determined warfarin resistance or underdosing. Oral anticoagulant monitoring in Trinidad and Tobago could benefit from the centralization of such services to designated clinics with specialized staff and computer-assisted dosing which adopt internationally accepted guidelines for practice.

Attitudes towards blood donation in Trinidad and Tobago.

The aims of this study were to determine the factors that influence blood donation in different demographic groups in a multi-ethnic, multicultural community, and to devise a strategy for a national campaign to increase voluntary non-remunerated blood donations. The majority (87%) of blood donations in Trinidad and Tobago are replacement donations. Seventy per cent of the country's transfusion needs are not met. In 1998, the World Health Assembly recommended that reliance on replacement donations should be phased out due to their association with an increased risk of transfusion-transmitted infections. An observer-administered questionnaire was completed by 1423 respondents in a multi-ethnic borough in central Trinidad. Respondents were classified as donors or non-donors and grouped by age, race, religion, employment status and highest level of education. The prevalence of a history of blood donation and the factors that encouraged donation or conversely discouraged donation in each demographic group were recorded. A total of 1146 (81.2%) respondents had never donated blood. Of the 277 (18.8%) who had previously donated, replacement for a family member or friend was the most common reason (86.9%). The prevalence of donation was low in all racial, religious, gender, educational and age groups. However, there were significant demographic variations. The majority (71.3%) of non-donors cited a lack of information as a major reason for non-donation and expressed a willingness to donate if access to information and donation facilities were improved. Voluntary blood donation in Trinidad and Tobago could be greatly increased by a national education campaign and increased accessibility to donation centres. This would ensure a safer and more reliable blood supply.

Hospital admissions for acute painful crisis in Trinidad and Tobago. Are the British Committee for Standards in Haematology (BCSH) guidelines applicable?

We observed consecutive hospital admissions for acute painful crisis (APC) among adults with Sickle Cell Disease (SCD) over a 6-month period in Trinidad and Tobago. Episodes (111) of APC resulted in 82 admissions of 59 patients. The most common site for pain was the trunk. Patients ranged in age from 17 to 53 years (median: 25). Median length of hospital stay was 4 days. Total dose of Pethidine given per admission ranged from 100 to 1650 mg (median: 525). The mean dose of morphine was 70 mg. Six (7%) of patients were readmitted within 10 days of discharge. Twenty-five (30%) of patients had chest pain at presentation of whom 10 (12%) had consolidation on chest X-ray, defining the acute chest syndrome (ACS). There was one death caused by biliary sepsis. The study revealed seemingly low opiate usage for in-hospital treatment of APC with acceptable rates of readmission. The BCSH 2003 guidelines seemed applicable apart for the choice and route of fluid for rehydration and opiate analgesia.

Hospital admissions for acute painful crisis in Trinidad and Tobago. Are the British Committee for Standards in Haematology (BCSH) guidelines applicable?

We observed consecutive hospital admissions for acute painful crisis (APC) among adults with Sickle Cell Disease (SCD) over a 6-month period in Trinidad and Tobago. Episodes (111) of APC resulted in 82 admissions of 59 patients. The most common site for pain was the trunk. Patients ranged in age from 17 to 53 years (median: 25). Median length of hospital stay was 4 days. Total dose of Pethidine given per admission ranged from 100 to 1650 mg (median: 525). The mean dose of morphine was 70 mg. Six (7%) of patients were readmitted within 10 days of discharge. Twenty-five (30%) of patients had chest pain at presentation of whom 10 (12%) had consolidation on chest X-ray, defining the acute chest syndrome (ACS). There was one death caused by biliary sepsis. The study revealed seemingly low opiate usage for in-hospital treatment of APC with acceptable rates of readmission. The BCSH 2003 guidelines seemed applicable apart for the choice and route of fluid for rehydration and opiate analgesia.

Audit of bone marrow aspirates and trephine biopsies in multiple myeloma--a single centre study.

We compared 79 simultaneous marrow aspirates and trephine biopsies from multiple myeloma patients for sensitivity, concordance, quality and clinical relevance. A total of 60 examinations had been performed for initial diagnosis, i.e. in cases of suspected myeloma and 19 at follow-up. Of which, 45 (57%) of trephine biopsies were less than 1.6 cm before processing and 33 (42%) were crushed and/or fragmented. Overall, only 19/79 (24%) of trephine biopsy specimens were of at least 1.6 cm length prior to processing and not disrupted. On the other hand, 75% of aspirates were particulate and satisfactory. Mean time between receipt of a trephine biopsy specimen and issuance of a histopathological report was 9 days. Although 40% of trephine biopsies yielded information that could not be reliably obtained from a bone marrow aspirate such information was in all cases clinically irrelevant or obtainable by non-invasive means. In all cases where myeloma was detected in a trephine biopsy it was also detected in a simultaneous bone marrow aspirate, if particulate. However, there were four (5%) cases in which myeloma was detected in such aspirates but not in simultaneously taken trephine biopsies. In cases (n=19) where repeat aspirates/trephine biopsies were taken for surveillance, concordance was found between reported changes in plasma cell ratio. Our data failed to demonstrate any added benefit from routinely performing trephine biopsies after a particulate specimen had been aspirated for the diagnosis or surveillance of myeloma. Furthermore, they suggest that particulate aspirates may be at least as sensitive as trephine biopsies for detecting myeloma.

Scrotal ulceration during all-trans retinoic (ATRA) therapy for acute promyelocytic leukaemia.

We report the development of painful scrotal ulceration in two patients during treatment with all-trans-retinoic acid (ATRA) for acute promyelocytic leukaemia (APL). ATRA 45 mg/m2 was administered orally for 8 days prior to the addition of standard induction chemotherapy. Painful scrotal ulceration developed in both cases within 2 weeks of therapy (9 and 13 days) and responded slowly to drug withdrawal and systemic, or topical, corticosteroids. A total of 17 APL patients have been treated with ATRA at our institution during the last 10 years, giving an incidence of approximately 12%. The present report, together with a review of literature, suggests that scrotal ulceration is a specific adverse effect of ATRA therapy and that this complication may be more common than previously documented.