Differential Virulence and Disease Progression following Mycobacterium tuberculosis Complex Infection of the Common Marmoset (Callithrix jacchus)

Existing small-animal models of tuberculosis (TB) rarely develop cavitary disease, limiting their value for assessing the biology and dynamics of this highly important feature of human disease. To develop a smaller primate model with pathology similar to that seen in humans, we experimentally infected the common marmoset (Callithrix jacchus) with diverse strains of Mycobacterium tuberculosis of various pathogenic potentials. These included recent isolates of the modern Beijing lineage, the Euro-American X lineage, and M. africanum. All three strains produced fulminant disease in this animal with a spectrum of progression rates and clinical sequelae that could be monitored in real time using 2-deoxy-2-[¹⁸F]fluoro-d-glucose (FDG) positron emission tomography (PET)/computed tomography (CT). Lesion pathology at sacrifice revealed the entire spectrum of lesions observed in human TB patients. The three strains produced different rates of progression to disease, various extents of extrapulmonary dissemination, and various degrees of cavitation. The majority of live births in this species are twins, and comparison of results from siblings with different infecting strains allowed us to establish that the infection was highly reproducible and that the differential virulence of strains was not simply host variation. Quantitative assessment of disease burden by FDG-PET/CT provided an accurate reflection of the pathology findings at necropsy. These results suggest that the marmoset offers an attractive small-animal model of human disease that recapitulates both the complex pathology and spectrum of disease observed in humans infected with various M. tuberculosis strain clades.     

Isolated first rib fracture in a child

We report a case of isolated first rib fracture in a child following blunt trauma. First rib fractures are not always associated with other serious injuries and could happen after minor trauma. The mechanism of injury needs to be taken into account when assessing a patient with first rib fracture. However a thorough clinical examination is necessary in patients presenting with first rib fracture to exclude other life and limb threatening injuries.     

Altered S100 Calcium-Binding Protein B and Matrix Metallopeptidase 9 as Biomarkers of Mesial Temporal Lobe Epilepsy with Hippocampus Sclerosis

Mesial temporal lobe epilepsy (MTLE) associated with hippocampal sclerosis (HS) is the most common form of partial epilepsy. The aim of the present study is to highlight possible and suitable biomarkers that can help in the diagnosis and prognosis of this intractable form of epilepsy. The study was carried out on 30 epileptic patients of both sexes with complex partial seizures, having an age ranging from 4 to 30 years and were selected from the outpatient epilepsy clinic at the Kasr El-Aini Hospital in Cairo, Egypt. Thirty healthy children and young adults, age- and sex-matched to the patients, were included in the study as controls. Patients with epilepsy and healthy controls were subjected to a set of laboratory analyses including S100 calcium-binding protein B (S100B), matrix metallopeptidase 9 (MMP9), C-reactive protein (CRP), and prolactin (PRL), in addition to neurophysiological, radiological, and psychometric assessments, on the basis of the recent evidence of the field. The results of this study showed a marked increase in the investigated biomarkers in patients with epilepsy compared to controls. The performance of the epileptic patients in psychometric assessments was below the average threshold, with the MRI analysis showing specific findings of mesial temporal sclerosis (MTS) and EEG showing anterior temporal spikes. A significant negative correlation was found between MMP9 and psychometric test. On the other hand, a significant positive correlation was observed between seizure severity and the indicated biomarker. The present study suggests that S100B and MMP9 could be used as biomarkers for neuronal injury and helps in the prognosis of MTLE.     

Role of protein kinase C in the expression of endothelin converting enzyme-1

Increased expression of endothelin converting enzyme-1 (ECE-1) is associated with diabetic nephropathy. The molecular mechanisms underlying this association, as yet unknown, possibly involve protein kinase C (PKC) pathways. In the present study, we examined the effects of high glucose and PKC activation on ECE-1 expression in primary human umbilical vein endothelial cells (HUVECs) and in HUVEC line (EA.hy926). Increasing glucose concentration, but not mannitol, from 5.5-22.2 mmol/liter for 3 d, enhanced prepro endothelin-1 (ET-1) mRNA expression, ET-1 levels, ECE-1 protein, and mRNA expressions by 7, 4, 20, and 2.6-fold, respectively. High glucose increased ECE-1 protein expression dose and time dependently. By Western blot analysis, PKC-beta1, -beta2, and -delta isoform levels were significantly increased relative to other isoforms when glucose level was increased. Treatment with Rottlerin, a PKC-delta isoform inhibitor, reduced significantly the glucose-induced ET-1 secretion, and ECE-1 protein expression, but (S)-13-[(dimethylamino)methyl]-10,11,14,15-tetrahydro-4,9:16,21-dimetheno 1H,1(3)H-dibenzo[e,k]pyrrolo[3,4-h] (1, 4, 3) oxadiaza-cyclohexadecene-1,3(2H)-dione or G?6976, specific PKC-beta and -alpha inhibitors, respectively, did not. Overexpression of PKC-delta but not PKC-alpha or -beta1 isoforms by adenovirus vector containing the respective cDNA in HUVECs incubated with 5.5 mmol/liter glucose, increased in parallel PKC proteins, and glucose-induced endothein-1 and ECE-1 protein expression by 4- to 6-fold. These results show that enhanced ECE-1 expression induced by hyperglycemia is partly due to activation of the PKC-delta isoform. Thus, inhibition of this PKC isoform may prevent diabetes-related increase in ET-1.     

An investigation of CO2 laser scleral buckling using moiré interferometry

BACKGROUND AND OBJECTIVE: To demonstrate suitability of moiré interferometry to assess and quantify laser-induced shrinkage of scleral collagen for buckling procedures. MATERIALS AND METHODS: Scleral buckling of human cadaver eyes was investigated using a Coherent Ultrapulse CO2 laser. Projection moiré interferometry was employed to determine the out-of plane displacement produced by laser exposure, and in-situ optical microscopy of reference markers on the eye was used to measure in-plane shrinkage. RESULTS: Measurements based on moiré interferometry allow a three dimensional view of shape changes in the eye surface as laser treatment proceeds. Out-of-plane displacement reaches up to 1.5 mm with a single laser spot exposure. In-plane shrinkage reached a maximum of around 30%, which is similar to that reported by Sasoh et al (Ophthalmic Surg Lasers. 1998;29:410) for a Tm:YAG laser. CONCLUSION: The moiré technique is found to be suitable for quantifying the effects of CO2 laser scleral shrinkage and buckling. This can be further developed to provide a standardized method for experimental investigations of other laser sources for scleral shrinkage.     

Gustatory function after tonsillectomy

OBJECTIVE: To assess taste function before and after tonsillectomy (TE). DESIGN: Prospective study. SETTING: University hospital. PATIENTS: Sixty-five patients (42 females, 23 males; mean age, 28 years). MAIN OUTCOME MEASURES: Taste function was investigated before TE with 4 concentrations each of sweet, sour, salty, and bitter quality, respectively, on both sides of the anterior and posterior areas of the tongue. Self-assessment of gustatory function was performed by visual analogue scales. Thirty-two patients were retested 64 to 173 days after TE. Thirty-three patients could not be retested after TE but were interviewed by telephone. RESULTS: Self-assessed taste function significantly decreased (P=.001). Yet, none of the subjects reported taste dysfunction. Tonsillectomy had no major effect on taste test scores (P>.27). CONCLUSION: Persisting taste dysfunction seems to be rare after TE.     

Nitric oxide: a key factor behind the dysfunctionality of endothelial progenitor cells in diabetes mellitus type-2

Diabetes mellitus type-2 (DM-2) contributes to atherogenesis by inducing endothelial cell injury and dysfunction. Endothelial progenitor cells (EPCs) are essential to blood vessel formation, can differentiate into mature endothelial cells, and promote the repair of damaged endothelium. In DM-2, the circulating EPC count is low and their functionality is impaired. The mechanisms that underlie this reduced count and impaired functionality are poorly understood. Nitric oxide (NO) is a short-lived signalling molecule that is produced by vascular endothelial cells and participates in the maintenance of vascular tone. NO is also known to participate in other physiological processes, such as cell survival, proliferation, and migration. The bioavailability of NO is reduced in EPCs from DM-2 patients. Interestingly, an inverse relationship exists between the reduction in NO bioavailability in EPCs and the patient's plasma glucose and glycated haemoglobin levels. In addition, NO bioavailability in EPCs correlates with plasma oxidized low-density lipoprotein levels in DM-2. Although this reduction in NO bioavailability could be attributed to oxidative stress in DM-2 patients, it also may be due to impairment of one or more members of the protein signalling cascades that are responsible for NO production. The stimulation of NO production or its signalling cascades in EPCs may increase their numbers and improve their function, thus attenuating endothelium damage, independent of the vasodilatory effects of NO. This review summarizes the metabolic alterations that underlie the molecular mechanisms that may be responsible for EPC decrease and dysfunction in DM-2 with emphasis on the involvement of the NO system.     

Secondary reduction of alpha7B integrin in laminin alpha2 deficient congenital muscular dystrophy supports an additional transmembrane link in skeletal muscle.

The integrins are a large family of heterodimeric transmembrane cellular receptors which mediate the association between the extracellular matrix (ECM) and cytoskeletal proteins. The alpha7beta1 integrin is a major laminin binding integrin in skeletal and cardiac muscle and is thought to be involved in myogenic differentiation and migration processes. The main binding partners of the alpha7 integrin are laminin-1 (alpha1-beta1-gamma1), laminin-2 (alpha2-beta1-gamma1) and laminin-4 (alpha2-beta2-gamma1). Targeted deletion of the gene for the alpha7 integrin subunit (ITGA7) in mice leads to a novel form of muscular dystrophy. In the present study we have investigated the expression of two alternative splice variants, the alpha7B and beta1D integrin subunits, in normal human skeletal muscle, as well as in various forms of muscular dystrophy. In normal human skeletal muscle the expression of the alpha7 integrin subunit appeared to be developmentally regulated: it was first detected at 2 years of age. In contrast, the beta1D integrin could be detected in immature and mature muscle in the sarcolemma of normal fetal skeletal muscle at 18 weeks gestation. The expression of alpha7B integrin was significantly reduced at the sarcolemma in six patients with laminin alpha2 chain deficient congenital muscular dystrophy (CMD) (age >2 years). However, this reduction was not correlated with the amount of laminin alpha2 chain expressed. In contrast, the expression of the laminin alpha2 chain was not altered in the skeletal muscle of the alpha7 knock-out mice. These data argue in favor that there is not a tight correlation between the expression of the alpha7 integrin subunit and that of the laminin alpha2 chain in either human or murine dystrophic muscle. Interestingly, in dystrophinopathies (Duchenne and Becker muscular dystrophy; DMD/BMD) expression of alpha7B was upregulated irrespective of the level of dystrophin expression as shown by a strong sarcolemmal staining pattern even in young boys (age <2 years). The expression of the beta1D integrin subunit was not altered in any of our patients with different types of muscular dystrophy. In contrast, sarcolemmal expression of beta1D integrin was significantly reduced in the alpha7 integrin knock-out mice, whereas the expression of the components of the DGC was not altered. The secondary loss of alpha7B in laminin alpha2 chain deficiency defines a biochemical change in the composition of the plasma membrane resulting from a primary protein deficiency in the basal lamina. These findings, in addition to the occurrence of a muscular dystrophy in alpha7 deficient mice, implies that the alpha7B integrin is an important laminin receptor within the plasma membrane which plays a significant role in skeletal muscle function and stability.     

Health Status,Persistent Symptoms,and Effort Intolerance One Year After Acute COVID-19 Infection

BackgroundThe long-term prevalence and risk factors for post-acute COVID-19 sequelae (PASC) are not well described and may have important implications for unvaccinated populations and policy makers.ObjectiveTo assess health status, persistent symptoms, and effort tolerance approximately 1 year after COVID-19 infectionDesignRetrospective observational cohort study using surveys and clinical dataParticipantsSurvey respondents who were survivors of acute COVID-19 infection requiring Emergency Department presentation or hospitalization between March 3 and May 15, 2020.Main Measure(s)Self-reported health status, persistent symptoms, and effort toleranceKey ResultsThe 530 respondents (median time between hospital presentation and survey 332 days [IQR 325–344]) had mean age 59.2±16.3 years, 44.5% were female and 70.8% were non-White. Of these, 41.5% reported worse health compared to a year prior, 44.2% reported persistent symptoms, 36.2% reported limitations in lifting/carrying groceries, 35.5% reported limitations climbing one flight of stairs, 38.1% reported limitations bending/kneeling/stooping, and 22.1% reported limitations walking one block. Even those without high-risk comorbid conditions and those seen only in the Emergency Department (but not hospitalized) experienced significant deterioration in health, persistent symptoms, and limitations in effort tolerance. Women (adjusted relative risk ratio [aRRR] 1.26, 95% CI 1.01–1.56), those requiring mechanical ventilation (aRRR 1.48, 1.02–2.14), and people with HIV (aRRR 1.75, 1.14–2.69) were significantly more likely to report persistent symptoms. Age and other risk factors for more severe COVID-19 illness were not associated with increased risk of PASC.ConclusionsPASC may be extraordinarily common 1 year after COVID-19, and these symptoms are sufficiently severe to impact the daily exercise tolerance of patients. PASC symptoms are broadly distributed, are not limited to one specific patient group, and appear to be unrelated to age. These data have implications for vaccine hesitant individuals, policy makers, and physicians managing the emerging longer-term yet unknown impact of the COVID-19 pandemic.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11606-021-07379-z.KEY WORDS: COVID-19, PASC, persistent symptoms