Gum Arabic as an Admixture in Modified Concrete Mixed with Calcined Kaolin

The use of calcined kaolin (CK) as a cementitious material in construction has attracted the interest of various researchers due to its environmental, mechanical, and physical qualities, all of which contribute to the lowering of cement usage. Studies have reported numerous problems associated with its use in concrete, apart from the ecological benefit that CK can provide. For instance, there is an issue of increased water demand due to smaller particle size, which generates much more heat in concrete, which has a detrimental effect on the mechanical and physical properties of concrete. This paper presents the analysis of an investigation aimed at using gum Arabic (GA) as a biopolymer admixture and calcined kaolin as a partial replacement of cement to improve the mechanical properties and durability of concrete. GA proportions ranged from 0 to 1% by weight of cement. Calcined kaolin (CK) was used to replace 5, 10, 15, 20, 25, and 30% of the cement content, respectively. Compressive strength, splitting tensile strength, density, strength loss, and weight loss tests were all performed to validate the structural performance of the modified concrete. The compressive tests, performed after 28 days from the time the mixture was made, demonstrated that the maximum percentage of CK that could replace cement without affecting the mechanical properties of concrete was 20%. Beyond 20%, concrete does not exhibit good compressive strength properties. The results also revealed decreased compressive strength and splitting tensile strength tests as the percentage of CK increased. After 56 days, compressive strength at 5% CK and 10% CK increased slightly by 0.743% and 1.162 %, respectively, compared to the control sample. The inclusion of 0.8%GA increased the compressive strength by 8.94% compared to the control sample (0%CK + 0%GA + 100%OPC) after 56 days. The results of durability tests showed that 0.6% GA had a higher compressive strength than other percentages containing GA. Doi: 10.28991/CEJ-2022-08-05-010 Full Text: PD

Factors associated with cardiac dysfunction following anthracyline-based chemotherapy in adults in a tertiary hospital in Nairobi

Introduction: Anthracyclines are known to improve survival in some malignancies, but may also be associated with irreversible cardiotoxicity, which is partly dose dependent. Early detection of cardiotoxicity provides an opportunity for treatment adjustment. Several parameters predict development of clinically manifest cardiac dysfunction. The study aimed to evaluate clinical and echocardiographic parameters which predict development of cardiac dysfunction in a sub-Saharan African population. Methods: Patients with a diagnosis of cancer and receiving anthracyclines at AKUH,N were evaluated if they met eligibility criteria (≥18years at first anthracycline administration, archived baseline echocardiogram, no prior history of heart disease or use of anthracyclines). Patients underwent echocardiographic, baseline clinical , drug therapy, radio-therapy and cardiovascular risk factor assessments. Echocardiographic global longitudinal strain (GLS), left ventricular (LV) ejection fraction and LV volumes were assessed. A relative decline from baseline in GLS of \u3e15%, an absolute decline in LVEF \u3e10 percentage points to \u3c53%, or symptomatic absolute decline in LVEF of 6-10 percentage points to \u3c53% defined LV dysfunction (cases). Factors associated with development ofLV dysfunction were compared between cases and controls (no LV dysfunction). Results: From 14-Oct-2013 to 11-Apr-2019, 504 patients who received anthracyclines were screened. 141 fullfilled inclusion criteria and were analysed (mean age, 47.7 years ± 11.2, Africans 95%, females 85.1%). Breast cancer patients were 82%, lymphoma 12%, sarcoma 5%, and leukaemia 1%. 39 (27.7%) had cardiac dysfunction, 30 of whom fulfilled the GLS criterion. Mean time interval between echocardiograms was 14.3 months (cases 16.4 ± 16.9; controls 14.4 ± 13.2), mean anthracycline dose was 244.7mg/m2 ± 72.2 (cases 254.5 ± 78.7; controls 241 ± 69.6), and mean symptom scores (DASI) were 50.0 ± 13.3 (cases 48.5 ± 13.4; controls 50.5 ± 13.2). Mean cardiotoxic doxorubicin equivalence dose was 236.7 mg/m2 ± 57.4 for cases and 217.3 ± 61.9 for controls [p = 0.033, OR = 1.00 (95% CI: 0.99 - 1.01)]. Cycle intervals, body surface area, body mass index, blood pressure, age, concomitant medication, radiation use and cardiovascular factors were similar. Echocardiographic parameters – E/a ratio and e’ were significantly reduced in cases (E/a 1.02 ± 0.33 for cases vs 1.16 ± 0.36 for controls, p =0.02: e’ 0.10 ± 0.05 for cases vs 0.11 ± 0.05 for controls, p =0.011). Conclusion: This is the first study evaluating early cardiotoxicity in an adult Sub-Saharan population receiving standard dose anthracyclines. The incidence of early cardiotoxicity was 27.7%, which was higher than in previously studied populations and had no relation to functional activity. Routine pre- and post-exposure cardiac assessment should be considered in an African population receiving anthracyclines to pre-empt the development of cardiac disease

Anthracycline associated cardiotoxicity in a subSaharan African population - tertiary care experience

Background Anthracyclines are associated with irreversible cardiotoxicity, with changes in echocardiographic parameters preceding clinically manifest cardiac dysfunction. We sought to evaluate the incidence of early cardiac dysfunction post anthracyclines, and associated clinical, echocardiographic and treatment parameters in a sub-Saharan African population. Methods Cancer patients aged ≥18years at anthracycline initiation with archived baseline echocardiograms, underwent repeat echocardiographic assessment. Cases (with cardiac dysfunction) had (1) \u3e15% relative decline from baseline in global longitudinal strain (GLS), or (2) a decline in left ventricular ejection fraction (LVEF) from baseline to \u3c53% with either (i) symptoms (assessed by the Duke Activity Status Index at follow-up echocardiogram) and LVEF decline by \u3e5 to ≤10%, or (ii) LVEF decline \u3e10% regardless of symptoms. Comparisons in clinical, echocardiographic and treatment parameters were made with controls (no cardiac dysfunction). Results Among 141 patients (mean age, 47.7years ± 11.2, Africans 95%, females 85.1%, breast cancer 82%), 39 (27.7%) had cardiac dysfunciton at a mean inter-echocardiogram interval of 14.9months ± 14.3, mean cumulative anthracycline dose of 244.7mg/m 2 ± 72.2, and mean DASI score was 50.0 ± 13.3. Mean cardiotoxic doxorubicin equivalence dose was 236.7mg/m 2 ± 57.4 for cases and 217.3 ± 61.9 for controls [p = 0.033, OR = 1.00 (95% CI: 0.99 - 1.01)]. The assessed clinical, echocardiographic and treatment parameters were not associated with cardiac dysfunction. Conclusion Incidence of early cardiac dysfunction after standard dose anthracyclines in an adult SubSaharan population is 27.7% at a mean follow-up of 14.9 months post anthracycline. Routine pre- and post-exposure cardiac assessment should be considered

Subclinical Cardiotoxicity Post Anthracycline in an African Population

Introduction: Anthracyclines, though known to improve survival in some malignancies, is known to be associated with cardiotoxicity. Early detection of cardiotoxicity provides an opportunity for treatment adjustment. Several parameters precede development of clinically manifest cardiac dysfunction. The study aimed to evaluate clinical and echocardiographic parameters associated with the development of cardiac dysfunction in a sub-Saharan African population. Methods: Cases and controls were respectively defined as cancer patients receiving anthracyclines at a tertiary centre where LV dysfunction on follow up echocardiogram did, or did not occur. Eligible patients were ≥18 years at first anthracycline dose, had an archived baseline echocardiogram, had no history of heart disease nor prior anthracycline use. Patients underwent baseline clinical, drug therapy and radio-therapy assessments. Baseline and follow-up left ventricular systolic and diastolic function were assessed. Subclinical LV dysfunction was defined according to the 2016 ESC position paper on cardiotoxicity (decline in LVEF and GLS). Results: Of 504 patients who received anthracyclines, 141 fullfilled inclusion criteria, with age 48 years, Africans 95%, females 85%, breast cancer 82%. 39 (27.7%) had cardiac dysfunction, 30 of whom fulfilled the GLS criterion. Mean echo follow up was 14.9 months (cases 16.4; controls 14.4), mean cardiotoxic doxorubicin equivalence dose was 237 mg/m2 for cases and 217 mg/m2 for controls (p = 0.033), mean DASI scores 49 for cases and 51 for controls. Cycle intervals, body surface area, body mass index, blood pressure, age, other therapy and cardiovascular factors were similar. E/a ratio and E’ were reduced in cases (E/a: 1.02 ± 0.33 vs 1.16 ± 0.36, p =0.02 and E: 0.10 ± 0.05 vs 0.11 ± 0.05 p =0.01). Conclusions: This is the first study evaluating subclinical cardiotoxicity after anthracycline use in an adult Sub-Saharan population. The incidence of subclinical cardiotoxicity in our study population, which received standard dose anthracyclines, was 27.7%, higher than previously studied populations. Routine pre- and post-exposure cardiac assessment should be considered at a low threshold in an African population receiving anthracyclines

Effects of Alternate Wet and Dry Conditions on the Mechanical and Physical Performance of Limestone Calcined Clay Cement Mortars Immersed in Sodium Sulfate Media

Sulfate attack in concrete structures significantly reduces their durability. This article reports the experimental findings on the effects of sodium sulfate on limestone calcined clay cement (LC3) in an alternate wet and dry media. The samples underwent wet–dry conditions of 28 cycles. Two types of LC3 were studied, one made from clay (LC3-CL) and the other made from fired rejected clay bricks (LC3-FR). The composition of each LC3 blend by weight was 50% clinker, 30% calcined clay, 15% limestone, and 5% gypsum. The reference compressive strength was evaluated at 2, 7, and 28 days of age. Then, ordinary Portland cement (OPC) and LC3-CL blends were subjected to alternate wet–dry cycle tests, immersion in a 5% sodium sulfate solution, or in water. For all exposed samples, sorptivity tests and compressive strength were done. The results showed that LC3 blends met the requirements for KS-EAS 18-1:2017 standard, which specifies the composition and conformity criteria for common cements in Kenya. The LC3 blend also had a lower rate of initial absorption compared to OPC. Additionally, LC3 blend also showed good resistance to sodium sulfate when exposed to alternating wetting and drying environment. OPC showed higher compressive strength than LC3 blends for testing ages of 2, 7, and 28 days. However, the LC3 samples utilized in the sodium sulfate attack experiment, which were later tested after 84 days, exhibited higher compressive strengths than OPC tested after the same period

Breast cancer clinical trials in East Africa

Purpose of Review: Breast cancer is one of the commonest cancers among women in sub-Saharan Africa. It occurs at an earlier age and with a more aggressive biology compared to the West. Yet despite this high prevalence and unusual phenotype, breast cancer in sub-Saharan African remains understudied, and this population is underrepresented in clinical trials. Recent Findings: While the immunohistochemical phenotype of breast cancer in East Africa and the West appears similar, there is growing evidence supporting the unique molecular nature of African breast cancer diagnosed. More needs to be done to study the African breast cancer genome, and effort invested to overcome the less than 2% participation of indigenous African patients in global clinical trials. To achieve this, investment needs to be made in training clinicians to become clinical investigators and more emphasis placed on clinical research in medical education. Summary: Breast cancer provides an important platform to study the demographic, biologic, and genomic differences of tumors diagnosed in African women. Active support for the study of such differences as well as promoting increased participation in clinical trials is critical to ensuring diversity, equity, and inclusivity of African patients in clinical trials

A rare case of breast carcinoma metastasis into a meningioma in a 64-year-old female patient

This report discusses the occurrence of tumor-to-tumor metastasis—an atypical phenomenon in oncology where a secondary malignancy develops within an existing primary tumor. The case of a 64-year-old woman is presented, who, with a history of stage II invasive ductal carcinoma of the breast treated with mastectomy and chemoradiotherapy, developed neurological symptoms indicative of a secondary brain tumor. MRI and subsequent histopathological analysis post-craniotomy confirmed a meningioma with a metastatic breast carcinoma, demonstrating the clinical importance of considering tumor-to-tumor metastasis in similar patient histories