Is titanium–zirconium alloy a better alternative to pure titanium for oral implant? Composition,mechanical properties,and microstructure analysis

IntroductionTitanium (Ti) is widely accepted as a biomaterial for orthopaedic and dental implants, primarily due to its capacity to integrate directly into the bone and its superior corrosion resistance. It has been suggested that titanium–zirconium alloy (TiZr), with 13–17% of zirconium, has better mechanical properties than pure Ti, but there are very few published studies assessing the suitability of TiZr for high-load- bearing implants. This study aimed to compare the mechanical properties and microstructures of TiZr and commercially pure titanium (Ti).MethodologyPure Ti and TiZr alloy discs were prepared and subjected to characterisation by nanoindentation, electron dispersive spectroscopy (EDS), X-ray diffraction (XRD), and electron backscatter diffraction (EBSD).ResultsThe TiZr alloy was found to have significantly lower elastic modulus value (p < 0.0001) and greater hardness than Ti (p < 0.05). The EDS results confirmed the presence of Zr (13–17%) in the TiZr alloy, with XRD and EBSD images showing microstructure with the alpha phase similar to commercially available Ti.ConclusionThe lower elastic modulus, higher hardness, presence of alpha phase, and the finer grain size of the TiZr alloy make it more suitable for high-load-bearing implants compared to commercially available Ti and is likely to encourage a positive biological response.     

Cross-protective immunity following coronavirus vaccination and coronavirus infection

Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines have shown efficacy against SARS-CoV-2, it is unknown if coronavirus vaccines can also protect against other coronaviruses that may infect humans in the future. Here, we show that coronavirus vaccines elicited cross-protective immune responses against heterologous coronaviruses. In particular, we show that a severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) vaccine developed in 2004 and known to protect against SARS-CoV-1 conferred robust heterologous protection against SARS-CoV-2 in mice. Similarly, prior coronavirus infections conferred heterologous protection against distinct coronaviruses. Cross-reactive immunity was also reported in patients with coronavirus disease 2019 (COVID-19) and in individuals who received SARS-CoV-2 vaccines, and transfer of plasma from these individuals into mice improved protection against coronavirus challenges. These findings provide the first demonstration to our knowledge that coronavirus vaccines (and prior coronavirus infections) can confer broad protection against heterologous coronaviruses and establish a rationale for universal coronavirus vaccines.     

History of pancreaticoduodenectomy: early misconceptions, initial milestones and the pioneers

Pancreaticoduodenectomy is one of the most challenging surgical procedures which requires the highest level of surgical expertise. This procedure has constantly evolved over the years through the meticulous efforts of a number of surgeons before reaching its current state. This review navigates through some of the early limitations and misconceptions and highlights the initial milestones which laid the foundation of this procedure. The current review also provides a few excerpts from the lives and illuminates on some of the seminal contributions of the three great surgeons: William Stewart Halsted, Walther Carl Eduard Kausch and Allen Oldfather Whipple. These surgeons pioneered the nascent stages of this procedure and paved the way for the modern day pancreaticoduodenectomy.     

Acrometastasis as the Initial Presentation of a KRAS-Positive Colon Cancer

The propensity of colon cancer to metastasize to bones is very low compared to prostate, breast or lung cancer. The reason for this is not yet understood, although an explanation for the osteotropism of certain primaries has been offered by the ‘seed and soil’ concept, suggesting that the bone microenvironment provides a favorable ‘soil’ for metastasis and proliferation of some tumor cells (‘seeds’) [1]. Here, we report an unusual case of colon cancer with metastasis to the finger at initial presentation, and exophytic sclerotic lesions to other bones. The incidence of metastases to fingers/toes (acrometastases) is reported to be only 0.1%, even after including involvement of primary sites other than the colon. The etiology and characteristics of acrometastases are reviewed in this case report.Key Words: Colon cancer, Acrometastasis, Finger, Bone, Amputation, KRAS     

Ocular biometry in an urban Indian population: the Singapore Indian Eye Study (SINDI)

PURPOSE. To describe the distribution and determinants of ocular biometric parameters in adult Singapore Indians. METHODS. A population-based, cross-sectional study was conducted on 3400 Indians aged 40 to 83 years residing in Singapore. Ocular components including axial length (AL), anterior chamber depth (ACD), and corneal radius (CR) were measured by partial coherence interferometry. Refraction was recorded in spherical equivalent (SE). RESULTS. After 502 individuals with previous cataract surgery were excluded, ocular biometric data on 2785 adults were analyzed. The mean AL, ACD, and CR were 23.45 ± 1.10, 3.15 ± 0.36, and 7.61 ± 0.26 mm, respectively. The mean AL/CR ratio was 3.08 ± 0.13. The mean AL was 23.53, 23.49, 23.35, and 23.25 mm in 40- to 49-, 50- to 59-, 60- to 69-, and 700 to 83-year age groups, respectively (P < 0.001). Men had significantly longer ALs than women (23.68 mm versus 23.23 mm, P < 0.001). In multivariate linear regression models, AL was found to be longer in adults who were taller (P < 0.001), better educated (University, P < 0.001), and more apt to spend time reading (P < 0.001). Increasing CR was associated with increasing height (P = 0.008). AL was the strongest determinant for refraction in all age groups, whereas lens nuclear opacity was a predictor in adults aged 60 to 83 years. CONCLUSIONS. The AL in Indians living in Singapore was similar to that of Malays in Singapore, but longer than that of Indians living in India. Time spent reading, height, and educational level were the strongest determinants of AL. AL was the strongest predictor of SE in all age groups.     

Left ventricular pseudoaneurysm: A case report and review of the literature

Left ventricular (LV) pseudoaneurysm is a rare complication that is reported in less than 0.1% of all patients with myocardial infarction. It is the result of cardiac rupture contained by the pericardium and is characterized by the absence of myocardial tissue in its wall unlike true aneurysm which involves full thickness of the cardiac wall. The clinical presentation of these patients is nonspecific, making the diagnosis challenging. Transthoracic echocardiogram and cardiac magnetic resonance imaging are the noninvasive modalities whereas coronary arteriography and left ventriculography are invasive modalities used for the diagnosis. As this condition is lethal, prompt diagnosis and timely management is vital.     

Water,sanitation, and hygiene practices mediate the association between women's empowerment and child length‐for‐age z‐scores in Nepal

In Nepal, more than one‐third of children are stunted. Prior studies have shown that women's empowerment in agriculture is associated with child (<2 years) length‐for‐age z‐scores (LAZ) in Nepal. This study tests whether child dietary diversity (DD) and household water, sanitation, and hygiene (WASH) facilities and practices mediate the associations between women's empowerment and LAZ. With a cross‐sectional dataset of 4,080 households from 240 rural communities across 16 districts of Nepal, we used ordinary least squares regression models to first estimate the associations between women's empowerment and LAZ for children 6 to 24 months (n = 1,402; our previous published analysis included all children <24 months of age), using the Women's Empowerment in Agriculture Index's Five Domains of Empowerment subindex. We used standardized structural equation models to test whether child DD and/or household WASH mediated the association between women's empowerment and child LAZ. Overall, women's empowerment was positively associated with child LAZ (β = 0.24, P = 0.03), as found in our previous analyses. In the mediation analysis, women's empowerment was positively associated with WASH (β = 0.78, P < 0.001), and in turn child LAZ (β = 0.09, P < 0.001). Women's empowerment was not associated with DD, but DD was associated with LAZ (β = 0.06, P = 0.05). Empowered women had better WASH practices than nonempowered women, which translated into higher child LAZ. Child DD was not a mediating factor in the association between women's empowerment and child LAZ. More research is needed to explore other pathways by which women's empowerment may affect child nutrition outcomes.     

Bacteriological study of pus isolates from neuropathic plantar ulcers associated with acute inflammatory phase

In this retrospective study, sensitivity of organisms cultured from ulcers of leprosy patients without and with diabetes mellitus, diabetic patients without leprosy and patients with ulcers from other causes was examined. The profile of organisms grown from these groups of patients did not differ significantly. However, there was a high prevalence of organisms like Proteus, E. coli and Enterococcus in the ulcers of leprosy patients indicating faecal contamination of the ulcers. Co-trimaxazole and tetracycline were of little value in the treatment of these ulcers. We therefore recommend that in situations where there is no culture facility, the patients be started on a course of penicillin and gentamycin. If these antibiotics fail, it would be necessary to use more advanced antibiotics like norfloxacin, amikacin and ciprofloxacin.