Hydroxyapatite/hyperbranched polyitaconic acid/chitosan composite scaffold for bone tissue engineering

In this study, a promising modified composite scaffold (hydroxyapatite/hyperbranched polyitaconic acid/chitosan) was synthesized for bone tissue engineering. Novel hyperbranched polyitaconic acid was prepared through the polymerization of itaconic acid using reversible addition fragmentation chain transfer using a macro‐RAFT agent. The chemical structure of the prepared hyperbranched polyitaconic acid was characterized by FTIR and 1HNMR and was subsequently embedded into hydroxyapatite/chitosan composite. The obtained modified composite scaffold was evaluated by characterizing its porosity, mechanical properties, bioactivity and cytotoxicity. The results showed that the modified composite scaffold had higher mechanical strength (i.e., 0.56 ± 0.03 MPa) in comparison to chitosan/hydroxyapatite scaffold only (i.e., 0.31 ± 0.01 MPa) and also showed higher bioactivity. In addition, the modified composite scaffold (HAP/HBP‐RAFT‐PI/CS) showed anticancer properties and enhanced human skin fibroblasts proliferation.

Using Mean Arterial Pressure in Hypertension Diagnosis versus Using Either Systolic or Diastolic Blood Pressure Measurements

Hypertension is a severe and highly prevalent disease. It is considered a leading contributor to mortality worldwide. Diagnosis guidelines for hypertension use systolic and diastolic blood pressure (BP) together. Mean arterial pressure (MAP), which refers to the average of the arterial blood pressure through a single cardiac cycle, can be an alternative index that may capture the overall exposure of the person to a heightened pressure. A clinical hypothesis, however, suggests that in patients over 50 years old in age, systolic BP may be more predictive of adverse events, while in patients under 50 years old, diastolic BP may be slightly more predictive. In this study, we investigated the correlation between cerebrovascular changes, (impacted by hypertension), and MAP, systolic BP, and diastolic BP separately. Several experiments were conducted using real and synthetic magnetic resonance angiography (MRA) data, along with corresponding BP measurements. Each experiment employs the following methodology: First, MRA data were processed to remove noise, bias, or inhomogeneity. Second, the cerebrovasculature was delineated for MRA subjects using a 3D adaptive region growing connected components algorithm. Third, vascular features (changes in blood vessel’s diameters and tortuosity) that describe cerebrovascular alterations that occur prior to and during the development of hypertension were extracted. Finally, feature vectors were constructed, and data were classified using different classifiers, such as SVM, KNN, linear discriminant, and logistic regression, into either normotensives or hypertensives according to the cerebral vascular alterations and the BP measurements. The initial results showed that MAP would be more beneficial and accurate in identifying the cerebrovascular impact of hypertension (accuracy up to 95.2%) than just using either systolic BP (accuracy up to 89.3%) or diastolic BP (accuracy up to 88.9%). This result emphasizes the pathophysiological significance of MAP and supports prior views that this simple measure may be a superior index for the definition of hypertension and research on hypertension.

The Role of Radiomics and AI Technologies in the Segmentation, Detection, and Management of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common primary hepatic neoplasm. Thanks to recent advances in computed tomography (CT) and magnetic resonance imaging (MRI), there is potential to improve detection, segmentation, discrimination from HCC mimics, and monitoring of therapeutic response. Radiomics, artificial intelligence (AI), and derived tools have already been applied in other areas of diagnostic imaging with promising results. In this review, we briefly discuss the current clinical applications of radiomics and AI in the detection, segmentation, and management of HCC. Moreover, we investigate their potential to reach a more accurate diagnosis of HCC and to guide proper treatment planning.

Cytocompatibility of MG-63 osteosarcoma cells on chitosan/hydroxyapatite/lignin hybrid composite scaffoldin vitro

This study aims at fabricating promising cytocompatible hybrid biocomposite scaffolds from chitosan (CS), hydroxyapatite (HAP) and lignin (L) for bone tissue engineering by using freeze-drying technique. Different ratios of HAP to L (50:0, 37.5:12.5, 25:25 and 12.5:37.5) were taken to determine the optimum ratio for obtaining a composite with superior properties. The mechanical and biological properties of the resulting composites were investigated. The mechanical results showed that the prepared composite with a ratio of 25:25 of HAP/L exhibited a remarkable enhancement in the mechanical properties compared to the others. Additionally, it was found from thein vitroresults that the addition of L enhanced the water uptake value of the resulting scaffolds indicating their increased hydrophilicity. As a result, a significant increase in the attachment and proliferation of MG-63 cell line (osteoblast like cells) was observed in composite scaffolds with L over the scaffold without L (CS/HAP). From these results, it could be suggested that the prepared composite scaffold with 25:25 of HAP/L is very promising biomaterials in bone tissue-engineering as it exhibited a better mechanical and biological properties than the other prepared composites.

How AI Can Help in the Diagnostic Dilemma of Pulmonary Nodules

Simple Summary

Pulmonary nodules are considered a sign of bronchogenic carcinoma, detecting them early will reduce their progression and can save lives. Lung cancer is the second most common type of cancer in both men and women. This manuscript discusses the current applications of artificial intelligence (AI) in lung segmentation as well as pulmonary nodule segmentation and classification using computed tomography (CT) scans, published in the last two decades, in addition to the limitations and future prospects in the field of AI.

Abstract

Pulmonary nodules are the precursors of bronchogenic carcinoma, its early detection facilitates early treatment which save a lot of lives. Unfortunately, pulmonary nodule detection and classification are liable to subjective variations with high rate of missing small cancerous lesions which opens the way for implementation of artificial intelligence (AI) and computer aided diagnosis (CAD) systems. The field of deep learning and neural networks is expanding every day with new models designed to overcome diagnostic problems and provide more applicable and simply used models. We aim in this review to briefly discuss the current applications of AI in lung segmentation, pulmonary nodule detection and classification.

Impact of stress and hypertension on the cerebrovasculature

OBJECTIVES

Both stress and hypertension (HTN) are considered major health problems that negatively impact the cerebral vasculature. In this article we summarize the possible relationship between stress and HTN.

METHODS

We conducted a systematic review of the literature using a database search of MEDLINE, PubMed, Scopus, and Web of Science.

RESULTS

Psychological stress is known to be an important risk factor for essential hypertension. Acute stress can induce transient elevations of blood pressure in the context of the fight-or-flight response. With increased intensity and duration of a perceived harmful event, the normal physiological response is altered, resulting in a failure to return to the resting levels. These changes are responsible for the development of HTN. Genetic and behavioral factors are also very important for the pathogenesis of hypertension under chronic stress situation. In addition, HTN and chronic stress may lead to impaired auto-regulation, regional vascular remodeling, and breakdown of the blood brain barrier (BBB). The effects of both HTN and chronic stress on the cerebral blood vessels shows that both have common structural and functional effects including endothelial damage with subsequent increased wall thickness, vessel resistance, stiffness, arterial atherosclerosis, and altered hemodynamics.

CONCLUSION

Most of the above mentioned vascular effects of stress were primarily reported in animal models. Further in-vivo standardization of pathological vascular indices and imaging modalities is warranted. Radiological quantification of these cerebrovascular changes is therefore essential for in depth understanding of the healthy and diseased cerebral arteries functions, identification and stratification of patients at risk of cardiovascular and neurological adverse events, enactment of preventive measures prior to the onset of systemic HTN, and the initiation of personalized medical management.

Role of smoking on body fat distribution and coronary artery disease

Introduction

Smoking and obesity are recognized as important modifiable risk factors for coronary artery disease (CAD). However, the general perception that smoking protects against obesity is a common reason for starting, and/or not quitting smoking.

Purpose

To detect the quantity, quality and relative distribution of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) estimated by abdominal computed tomography in smokers versus non- smokers.

Methods

The abdominal muscular wall was traced manually to calculate SAT and VAT areas (cm2) (outside and inside abdominal muscular wall respectively) as well as SAT density [Hounsfield units (HU)] at L4-L5 in 409 consecutive patients referred for evaluation of chest pain by multi-slice computed tomography coronary angiography (MSCT-CA).

Results

26% of the studied patients (n=107) were current smokers, while the remaining 74% (n=302) never smoked. Coronary artery atherosclerosis was more prevalent in smokers compared to non-smokers (64.5% vs 55.0%; p=0.09). Smokers had statistically significantly lower body mass index (BMI) (31.2±4.3 vs. 32.5±4.7 kg/m2; p=0.015), hip circumference (HC) (98.6±22.5 vs. 103.9±20.9 cm; p=0.031), total fat area (441.62±166.34 vs. 517.95±169.51cm2; p<0.001), and SAT area (313.07±125.54 vs. 390.93±143.28 cm2; p<0.001) as compared to non-smokers. However, smokers had statistically significantly greater waist-to-hip ratio (0.98±0.08 vs. 0.96±0.08; p=0.010), VAT/SAT area ratio (0.41±0.23 vs. 0.35±0.20; p=0.013), and denser SAT depot (−98.91±7.71 vs. −102.08±6.44 HU; p<0.001).

Conclusion

Smoking contributes to CAD and to the pathogenic redistribution of body fat towards VAT, through limiting SAT potential to expand.

Funding Acknowledgement

Type of funding source: None

A novel computer-aided diagnosis system for the early detection of hypertension based on cerebrovascular alterations

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3-D CNN segmentation succeeded in delineating cerebrovasculature accurately.

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Segmentation approach is automatic and applicable on healthy/pathological vessels.

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Blood flow variability challenge was addressed by processing MRA scans locally.

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Proposed vascular features were efficient to quantify cerebral changes.

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Proposed CAD system could help clinicians predict hypertension before its onset.

Hypertension is a leading cause of mortality in the USA. While simple tools such as the sphygmomanometer are widely used to diagnose hypertension, they could not predict the disease before its onset. Clinical studies suggest that alterations in the structure of human brains’ cerebrovasculature start to develop years before the onset of hypertension. In this research, we present a novel computer-aided diagnosis (CAD) system for the early detection of hypertension. The proposed CAD system analyzes magnetic resonance angiography (MRA) data of human brains to detect and track the cerebral vascular alterations and this is achieved using the following steps: i) MRA data are preprocessed to eliminate noise effects, correct the bias field effect, reduce the contrast inhomogeneity using the generalized Gauss-Markov random field (GGMRF) model, and normalize the MRA data, ii) the cerebral vascular tree of each MRA volume is segmented using a 3-D convolutional neural network (3D-CNN), iii) cerebral features in terms of diameters and tortuosity of blood vessels are estimated and used to construct feature vectors, iv) feature vectors are then used to train and test various artificial neural networks to classify data into two classes; normal and hypertensive. A balanced data set of 66 subjects were used to test the CAD system. Experimental results reported a classification accuracy of 90.9% which supports the efficacy of the CAD system components to accurately model and discriminate between normal and hypertensive subjects. Clinicians would benefit from the proposed CAD system to detect and track cerebral vascular alterations over time for people with high potential of developing hypertension and to prepare appropriate treatment plans to mitigate adverse events.

P5608Acute respiratory failure after type A aortic dissection repair: data from the International Registry of Aortic Dissection (IRAD)

Background

Acute Respiratory Failure (ARF) has been noted in up to 20% of patients undergoing cardiac surgery and is associated with increased mortality. Cardiopulmonary bypass (CPB) is often followed by pulmonary dysfunction, although literature on the subject in the setting of Type A acute aortic dissection (TAAAD) is limited.

Methods

This study identified the incidence of ARF after TAAAD, associated risk factors, and the impact of ARF on early and late outcomes. All data have been derived from the International Registry of Acute Aortic Dissection (IRAD).

Results

Postoperative ARF (defined as ventilator support for ≥3 days, tracheostomy, and/or pneumonia) occurred in 434 (24.6%) of 1764 surgically managed TAAAD patients (mean age 60.1±14.2 years) from November 2001 until November 2017. Peripheral vessel procedures (6.4% v 2.8%, p=0.002), cerebral perfusion (89.2% v 82.3%, p<0.001), use of hypothermic circulatory arrest (93% v 87.7%), longer arrest time (median 39 (Q1-Q3 27–128 minutes) v 31 (Q1-Q3 22.0–52.9 minutes)), and lower extremity ischemia (18.8% v 6.7%, p<0.001) were more common in ARF patients.

On multivariable logistic regression analysis, age ≥70 years (OR 1.019, 95% CI 1.005–1.034, p=0.008), current smoking (OR 1.744, 95% CI 1.184–2.570, p=0.005), peripheral vessel procedures (OR 2.457, 95% CI 1.132–5.334, p=0.023), presenting hypotension/shock (OR 2.036, 95% CI 1.336–3.102, p=0.001), lower extremity ischemia at surgery (OR 2.77, 95% CI 1.574–4.875, p<0.001), concomitant coronary artery bypass graft (CABG) (OR 2.982, 95% CI 1.597–5.568, p=0.001), pre-operative acute renal failure (OR 2.532, 95% CI 1.350–4.749, p=0.004), and prolonged circulatory arrest time in minutes (OR 1.005, 95% CI 1.003–1.007, p<0.001) were independently associated with ARF development. Patients with aortic valve replacement (AVR) were less likely to develop ARF (OR 0.497, 95% CI 0.308–0.802, p=0.004).

Post-operative complications were more common in ARF patients. In-hospital mortality was higher in the ARF cohort (16.4% v 4.7%, p<0.001). Multivariable logistic regression identified ARF (OR 2.686, 95% CI 1.647–4.381, p<0.001) as well as pre-operative hypotension (OR 1.89, 95% CI 1.130–3.159, p=0.015), lower extremity ischemia (OR 2.77, 95% CI 1.545–4.998, p=0.001), pre-operative myocardial infarction (OR 3.141, 95% CI 1.058–9.33, p=0.039), and CABG (OR 1.988, 95% CI 1.011–3.909, p-value 0.047) as independent predictors of death.

Conclusions

Post-operative ARF is common after TAAAD repair; in-hospital complications and death are higher in this cohort.

Acknowledgement/Funding

W.L. Gore & Associates, Inc.; Medtronic; Varbedian Aortic Fund; Hewlett Foundation; Mardigian Foundation; UM Faculty Group Practice; Ann & Bob Aikens

P3379Diagnostic value of cardiac computed tomographic angiography in suspected prosthetic valve dysfunction

Background

Echocardiographic assessment of prosthetic mechanical valves is limited by shadows, artefacts and the need for cumbersome Doppler calculations. CT scan has the potential to overcome some of the limitations of echocardiography in assessment of prosthetic valves.

Objectives

Determine the incremental diagnostic value of cardiac computed tomographic angiography (CTA) over transesophageal echocardiography (TEE) in patients with suspected prosthetic valve dysfunction (PVD) and its impact on treatment decisions.

Methods

50 consecutive patients with suspected PVD underwent both 64-slice ECG-gated CT and TEE and the results were compared. Imaging was compared against surgical findings (Reference standard). Echocardiographic evaluation focused on the detection of signs of PVD: vegetations, new or increased paravalvular leakage (PVL), aortic root pseudoaneurysms or abscesses and occluder malfunction. The CT interpreter was blinded to the findings of TEE.

Results

ECG-gated CT showed findings that were not detected by TEE in fifteen patients (30%). Additional aortic root abscess in four patients (8%), additional aortic root pseudoaneurysm in four patients (8%), and sclero-degenerative change across one of occluder of aortic prosthesis as cause of PVL in another patient (2%) not detected by TEE. CT negated the presence of aortic root abscess in one patient (2%), negated the presence of PVL in another patient (2%) both were detected by TEE. CT diagnosed occluder malfunction in one patient (2%) and underlying cause in two patients (4%) both were not detected by TEE. CT diagnosed presence of aortic arch dissection in one patient (2%) with large aortic root pseudoaneurysm.

CT showed minor diagnostic change in six patients (12%). CT showed better delineation of site and periannular extension of aortic root abscess in four patients (8%). CT showed better assessment severity of PVL in one patient (2%) and cause of PVL across mechanical aortic prosthesis in another patient (2%).

CT resulted in change of treatment strategy in 14 patients (28%). This included surgical excision of additional aortic root abscess or aortic root pseudoaneurysm in four patients (8%), surgical removal of prosthesis for underlying pathology (vegetation, malfunction due to underlying thrombus or PVL) in four patients (8%), aortic arch replacement with tubular graft and reimplantation of coronaries in one patient (2%) and conservative treatment with antibiotic therapy for small aortic root abscess not detected by TEE in 2 patients (4%), proper anticoagulation therapy and close monitor of INR in one patient (2%).

Conclusion

ECG-gated CT and TEE are complementary in patients with prosthetic valve dysfunction. Therefore, CT imaging has to be considered after clinical routine workup and TEE in patients with a high suspicion on prosthetic valve dysfunction.

A Novel Framework for Early Detection of Hypertension using Magnetic Resonance Angiography

Hypertension is a leading mortality cause of 410,000 patients in USA. Cerebrovascular structural changes that occur as a result of chronically elevated cerebral perfusion pressure are hypothesized to precede the onset of systemic hypertension. A novel framework is presented in this manuscript to detect and quantify cerebrovascular changes (i.e. blood vessel diameters and tortuosity changes) using magnetic resonance angiography (MRA) data. The proposed framework consists of: 1) A novel adaptive segmentation algorithm to delineate large as well as small blood vessels locally using 3-D spatial information and appearance features of the cerebrovascular system; 2) Estimating the cumulative distribution function (CDF) of the 3-D distance map of the cerebrovascular system to quantify alterations in cerebral blood vessels' diameters; 3) Calculation of mean and Gaussian curvatures to quantify cerebrovascular tortuosity; and 4) Statistical and correlation analyses to identify the relationship between mean arterial pressure (MAP) and cerebral blood vessels' diameters and tortuosity alterations. The proposed framework was validated using MAP and MRA data collected from 15 patients over a 700-days period. The novel adaptive segmentation algorithm recorded a 92.23% Dice similarity coefficient (DSC), a 94.82% sensitivity, a 99.00% specificity, and a 10.00% absolute vessels volume difference (AVVD) in delineating cerebral blood vessels from surrounding tissues compared to the ground truth. Experiments demonstrated that MAP is inversely related to cerebral blood vessel diameters (p-value < 0.05) globally (over the whole brain) and locally (at circle of Willis and below). A statistically significant direct correlation (p-value < 0.05) was found between MAP and tortuosity (medians of Gaussian and mean curvatures, and average of mean curvature) globally and locally (at circle of Willis and below). Quantification of the cerebrovascular diameter and tortuosity changes may enable clinicians to predict elevated blood pressure before its onset and optimize medical treatment plans of pre-hypertension and hypertension.

The ESC ACCA EAPCI EORP acute coronary syndrome ST-elevation myocardial infarction registry

Aims 

The Acute Cardiac Care Association (ACCA)–European Association of Percutaneous Coronary Intervention (EAPCI) Registry on ST-elevation myocardial infarction (STEMI) of the EurObservational programme (EORP) of the European Society of Cardiology (ESC) registry aimed to determine the current state of the use of reperfusion therapy in ESC member and ESC affiliated countries and the adherence to ESC STEMI guidelines in patients with STEMI.

Methods and results 

Between 1 January 2015 and 31 March 2018, a total of 11 462 patients admitted with an initial diagnosis of STEMI according to the 2012 ESC STEMI guidelines were enrolled. Individual patient data were collected across 196 centres and 29 countries. Among the centres, there were 136 percutaneous coronary intervention centres and 91 with cardiac surgery on-site. The majority of centres (129/196) were part of a STEMI network. The main objective of this study was to describe the demographic, clinical, and angiographic characteristics of patients with STEMI. Other objectives include to assess management patterns and in particular the current use of reperfusion therapies and to evaluate how recommendations of most recent STEMI European guidelines regarding reperfusion therapies and adjunctive pharmacological and non-pharmacological treatments are adopted in clinical practice and how their application can impact on patients’ outcomes. Patients will be followed for 1 year after admission.

Conclusion 

The ESC ACCA-EAPCI EORP ACS STEMI registry is an international registry of care and outcomes of patients hospitalized with STEMI. It will provide insights into the contemporary patient profile, management patterns, and 1-year outcome of patients with STEMI.

Ochromobactrum intermedium: an emerging opportunistic pathogen-case of recurrent bacteraemia associated with infective endocarditis in a haemodialysis patient

We describe the first clinical case report of infective endocarditis related to Ochrobactrum intermedium infection. The case involved a 23-year-old man receiving dialysis via an internal jugular long-term haemodialysis catheter. He improved with a prolonged course of meropenem and minocycline. Ochrobactrum spp. are recognized as rare emerging opportunistic pathogens.

Regulation of dendritic cell interleukin-12 secretion by tumour cell necrosis

Dendritic cells (DCs) play a key role in the induction and regulation of antigen-specific immunity. Studies have shown that, similar to infection, cellular necrosis can stimulate DC maturation. However, the ability of necrotic cell death to modulate DC cytokine secretion has yet to be explored. We investigated the regulation of interleukin (IL)-12 secretion by human DCs in response to tumour cell necrosis in an in vitro culture model. Two human tumour cell lines (K562 and JAr) were induced to undergo necrosis using heat injury and repeated cycles of freezing and thawing. Both types of tumour cells tested in this study, when injured, induced secretion of monomeric IL-12p40 by monocyte-derived DCs. Furthermore, priming DCs with necrotic cells augmented IL-12p70 secretion significantly in conjunction with CD40 cross-linking. This was physiologically relevant because cell death-pulsed DCs were more potent than non-pulsed DCs at stimulating T cells to proliferate and secrete interferon (IFN)-gamma. The Toll-like receptor 4 (TLR4) played a role in mediating the DC response to heat-killed, but not freeze/thaw-killed necrotic cells. For both methods of injury, proteins contributed to the effect of necrosis on dendritic cells, whereas DNA was involved in the effect of freeze/thawed cells only. These findings indicate that necrotic tumour cell death is not sufficient to induce bioactive IL-12p70, the Th1 promoting cytokine, but acts to augment its secretion via the CD40/CD40L pathway. The results also highlight that the mode of cell death may determine the mechanism of dendritic cell stimulation.

Renal cell carcinoma metastatic to the pituitary gland: clinical manifestations and successful treatment with transsphenoidal resection

OBJECTIVE

To describe two cases of metastatic involvement of the pituitary gland by renal cell carcinoma (RCCA) and review the medical literature regarding this entity.

METHODS

We present two case reports and discuss the published literature to illustrate the clinical findings, radiographic features, and recommended management of RCCA metastatic to the pituitary gland.

RESULTS

During a 12-month period, we encountered two patients, one with visual deficits and both with anterior pituitary dysfunction, who had large sellar lesions that were histologically proved to be RCCA. Both patients were successfully treated with transsphenoidal surgical resection of the lesion, one of whom is alive and well more than 2 years later. A pituitary metastatic tumor is an uncommon complication of RCCA; it may be difficult to diagnose and potentially fatal. Anterior pituitary dysfunction and visual disturbances are more common initial features than is diabetes insipidus, in contrast to pituitary metastatic involvement from other tumors.

CONCLUSION

Transsphenoidal resection is a safe and effective method of treatment of RCCA metastatic to the pituitary gland.

Hypertension prevalence, awareness, treatment, and control in Egypt. Results from the Egyptian National Hypertension Project (NHP). NHP Investigative Team

This report from the Egyptian National Hypertension Project presents national estimates of the prevalence of hypertension and the extent to which high blood pressure is being detected, treated with medications, and controlled in the Egyptian population. The results are based on findings from a national probability survey of adults > or = 25 years of age conducted in six Egyptian governorates. With the use of a stratified multistage probability design, 6733 people (85% response rate) were examined. Hypertension was defined as systolic pressure > or = 140 mm Hg, and/or diastolic pressure > or = 90 mm Hg, and/or reported treatment with one or more antihypertensive medications. Overall, the estimated prevalence of hypertension in Egypt was 26.3%. Hypertension prevalence increased progressively with age, from 7.8% in 25- to 34-year-olds to 56.6% in those 75 years or older. Hypertension was slightly more common in women than in men (26.9% versus 25.7%, respectively). Overall, 37.5% of hypertensive individuals were aware that they had high blood pressure, 23.9% were being treated with antihypertensive medications, and 8.0% were under control (systolic pressure < 140 mm Hg and diastolic pressure < 90 mm Hg). Hypertension prevalence as well as awareness, treatment, and control rates varied by region, with Cairo having the highest prevalence (31.0%) and the Coastal Region having the highest control rate (15.9%). Rates of awareness, treatment, and control tended to be lowest in areas of lower socioeconomic status. Our results indicate that hypertension is highly prevalent in Egypt and that the rates of hypertension is awareness, treatment, and control are relatively low.(ABSTRACT TRUNCATED AT 250 WORDS)

[Doppler echocardiographic evaluation of functional parameters of mechanical and biological valve prostheses]

We studied and compared functional parameters in 314 valvular prostheses. The following parameters have been calculated: mean transvalvular gradients for aortic and mitral prostheses and functional area by Pht (pressure half time) for mitral prostheses. All patients with important depression in myocardial function, tachycardia or malfunctioning prostheses were excluded. 173 prostheses were in aortic position and 141 in mitral position. Mitral prostheses were: 31 biological and 110 mechanical. We subdivided mechanical prostheses in monoleaflet (Omnicarbon, Sorin-Carbocast and Allcarbon, Medtronic, Bjork-Shiley) and bileaflet (Sorin-Bicarbon, St. Jude). These three groups were compared: mean transvalvular gradients and area showed no differences. Aortic prostheses were: 33 biological and 140 mechanical; mechanical prostheses were subdivided in two groups: monoleaflet (Sorin Allcarbon e Carbocast, Bjork-Shiley, Medtronic, Omnicarbon) and bileaflet (Sorin-Bicarbon, St. Jude). Mean transvalvular gradients of these three groups were compared within each group for every size: bileaflet prostheses demonstrated inferior gradients than biological and monoleaflet for 19-21 and 23 sizes; in superior sizes there were no significant differences. Further analysis showed a significant correlation among gradients and body surface area in the 21 size prostheses (p = 0.004). Bileaflet prostheses in this subgroup showed less increase in mean gradient with surface area than mechanical and biological ones.

Nitrogen balance and protein turnover during the growth failure in newly born low-birth-weight infants

Weight gain, nitrogen balance, protein turnover, and energy and protein intakes were measured during the first week of life of 14 low-birth-weight (LBW) infants, 5 small-for-gestational-age (SGA) infants and 9 appropriate-for-gestational-age (AGA) infants enterally fed at rates determined by the infants ability to assimilate feed. Mean gross intakes were 334 KJ and 1.75 g/kg protein; 4 infants were increasing and 10 were losing weight at rates proportional to gross energy and protein intakes and to nitrogen balance (0.031 g protein balance/g wt gain). Rates of protein synthesis and degradation measured by an intragastric infusion of [1-13C]leucine, averaged 14.5 and 15.9 g protein.kg-1.d-1, some 50% higher than previously reported in older preterm infants and not correlated with nitrogen balance. The growth failure of these infants was not associated with inadequate overall rates of protein turnover, but appeared to reflect an influence of the insufficient energy and protein intakes on the high rates of protein turnover, inducing changes in protein balance in either direction through relatively small changes in protein synthesis and/or degradation.

Regurgitant jet size by transesophageal compared with transthoracic Doppler color flow imaging

Combined echocardiography and Doppler color flow mapping from transthoracic imaging windows has become the standard method for the noninvasive assessment of valvular regurgitation. This study compared regurgitant jet areas by Doppler color flow imaging derived from the newer transesophageal approach with measurements obtained from conventional transthoracic apical views. Maximal regurgitant jet area determinations and an overall visual estimate of lesion severity were obtained from 42 patients who underwent color flow examination by both techniques. Seventy-three regurgitant lesions were visualized by transesophageal flow imaging: 34 mitral, 22 aortic, and 17 tricuspid jets. Transthoracic studies in the same patients revealed fewer regurgitant lesions for each valve; 20 mitral, 16 aortic, and 12 tricuspid (p = 0.0009). A comparison of maximal jet areas determined by transesophageal and transthoracic studies showed a good overall correlation (r = 0.85, SEE = 2.8 cm2) and a systematic overestimation by the transesophageal technique (TEE = 0.96 TTX + 2.7). For the subgroup with mitral insufficiency, valve lesions visualized by both techniques were larger by the transesophageal approach (n = 18, 6.0 versus 3.6 cm2, p = 0.008). Semiquantitative visual grading of individual valve lesions by two independent observers revealed a higher grade of regurgitation with more jets classified as mild (38 versus 25), moderate (18 versus 13), and severe (17 versus 10) by esophageal imaging than by transthoracic imaging. Thus, transesophageal color flow mapping techniques yield a higher prevalence of valvular regurgitation than do transthoracic techniques in the same patients. Jet area and the overall estimate of regurgitant lesion severity were also greater by transesophageal color Doppler imaging compared with standard transthoracic imaging.(ABSTRACT TRUNCATED AT 250 WORDS)

Morbidity and mortality of bacterial meningitis in Arab children

Between September 1981 and March 1987, 92 episodes of bacterial meningitis in 90 children were treated in three major hospitals in Kuwait. The diagnosis was bacteriologically confirmed in 80 (87%). Haemophilus influenzae was the most common aetiological organism and accounted for 42 episodes (45.6%) followed by Streptococcus pneumoniae in 21 (22.8%) and Neisseria meningitidis in only three (3.3%). Bacterial meningitis occurred in 53 children (57.6%) below the age of 1 year and in 81 (88%) below 5 years. The overall case fatality rate was 5.4% and ten children (9%) had severe neurological sequelae of their disease. Sequelae were more common following pneumococcal meningitis (28%) than after Haemophilus (7%). All 12 children with unknown pathogen recovered completely.

Erythrocyte protoporphyrin screening for lead poisoning in Bedouin children. A study from Kuwait

Screening for lead poisoning can be performed by measuring either blood lead (PbB) or a haematological indicator such as erythrocyte protoporphyrin (EP). We have screened 902 infants and children aged from 3 months to 5 years amongst those attending three primary health care centres in AI Jahra governorate of Kuwait. Blood specimens were collected by finger prick on Guthrie filter paper and the dried blood samples were mailed to the Central Laboratory of the Children's Hospital, Buffalo, USA. One hundred and eighty-four (20 per cent) had an elevated EP (greater than 50 micrograms/dl). Of those 11 had values above 159 micrograms/dl; 140 children were further tested for blood lead levels (PbB) haemoglobin, mean cell volumes, and percentage of transferrin saturation; 41 had blood lead levels greater than 25 micrograms/dl which is the current definition of elevated blood lead levels. Two children (2 per cent) were in Class IV, 17 (15 per cent) and 16 (14 per cent) were in Class II and Class III, respectively. There was a significant correlation between EP and PbB (r = 0.686; P = less than 0.001). Of 72 children with elevated EP and normal PbB, 32 were anaemic (Hb less than 11 g/dl) and 20 had iron deficiency. The role of tribal practices using lead contaminated preparations and their contribution to elevated blood lead levels is discussed.