Rethinking Fluid Responsiveness during Septic Shock: Ameliorate Accuracy of Noninvasive Cardiac Output Measurements through Evaluation of Arterial Biomechanical Properties.

Beat-to-beat estimates of cardiac output from the direct measure of peripheral arterial blood pressure rely on the assumption that changes in the waveform morphology are related to changes in blood flow and vasomotor tone. However, in septic shock patients, profound changes in vascular tone occur that are not uniform across the entire arterial bed. In such cases, cardiac output estimates might be inaccurate, leading to unreliable evaluation of fluid responsiveness. Pulse wave velocity is the gold-standard method for assessing different arterial biomechanical properties. Such methods might be able to guide, personalize and optimize the management of septic patients.

Closed-Loop Microreactor on PCB for Ultra-Fast DNA Amplification: Design and Thermal Validation.

Polymerase chain reaction (PCR) is the most common method used for nucleic acid (DNA) amplification. The development of PCR-performing microfluidic reactors (µPCRs) has been of major importance, due to their crucial role in pathogen detection applications in medical diagnostics. Closed loop (CL) is an advantageous type of µPCR, which uses a circular microchannel, thus allowing the DNA sample to pass consecutively through the different temperature zones, in order to accomplish a PCR cycle. CL µPCR offers the main advantages of the traditional continuous-flow µPCR, eliminating at the same time most of the disadvantages associated with the long serpentine microchannel. In this work, the performance of three different CL µPCRs designed for fabrication on a printed circuit board (PCB) was evaluated by a computational study in terms of the residence time in each thermal zone. A 3D heat transfer model was used to calculate the temperature distribution in the microreactor, and the residence times were extracted by this distribution. The results of the computational study suggest that for the best-performing microreactor design, a PCR of 30 cycles can be achieved in less than 3 min. Subsequently, a PCB chip was fabricated based on the design that performed best in the computational study. PCB constitutes a great substrate as it allows for integrated microheaters inside the chip, permitting at the same time low-cost, reliable, reproducible, and mass-amenable fabrication. The fabricated chip, which, at the time of this writing, is the first CL µPCR chip fabricated on a PCB, was tested by measuring the temperatures on its surface with a thermal camera. These results were then compared with the ones of the computational study, in order to evaluate the reliability of the latter. The comparison of the calculated temperatures with the measured values verifies the accuracy of the developed model of the microreactor. As a result of that, a total power consumption of 1.521 W was experimentally measured, only ~7.3% larger than the one calculated (1.417 W). Full validation of the realized CL µPCR chip will be demonstrated in future work.

Association of Pressure Wave Reflections With Left Ventricular Mass: a Systematic Review and Meta-Analysis.

BACKGROUND: Pressure wave reflections (PWRs) within the circulation are assessed at various arterial sites by various noninvasive methods. We aimed at reviewing the conflicting data regarding the hypothesis that higher PWRs are associated with higher left ventricular mass and tested whether this association stands for all available indices of PWRs, all (proximal or distal to the heart) sites of assessment, and is modified by sex, age and heart rate. METHODS: Based on a predefined protocol applying the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) guidelines, we identified eligible for meta-analysis data regarding: augmentation index, augmentation pressure, backward pressure (Pb), reflection index, and their association with left ventricular mass index (19 studies, total population n=8686). RESULTS: We found statistically significant associations, independent from blood pressure level, for all indices of PWRs at all arterial sites (carotid augmentation index; odds ratio; standardized beta coefficient [ß]: 0.14 [95% CI, 0.07% to 0.21%], per SD increase), radial augmentation index (ß: 0.21; 0.11 to 0.31), central augmentation pressure (ß: 0.15; 0.03 to 0.27), central Pb (ß: 0.23; 0.05 to 0.42), and central reflection index (ß: 0.14; 0.06 to 0.22), except for aortic augmentation index as estimated by generalized transfer functions. Meta-regression analysis showed that the association between carotid augmentation index and left ventricular mass was higher among populations with higher heart rate (P=0.036, beta: 0.017 [95% CI, 0.001 to 0.033]) and tended to be higher in middle-aged (P=0.07, beta: -0.001; -0.021 to 0.001). CONCLUSIONS: A clinically meaningful association between PWRs and left ventricular mass, assessed at either central or peripheral arterial sites by most available methods was shown, suggesting that PWR reduction strategies might be useful. Based on the present evidence, such trials should target middle-aged populations with high normal heart rate.

Assessment of Early Markers of Cardiovascular Risk in Polycystic Ovary Syndrome.

Polycystic ovary syndrome (PCOS) is a heterogeneous syndrome, with long-term sequelae from birth to senescence. The long-term effects of PCOS are attributed to several metabolic aberrations ensuing the syndrome. In a systematic review of literature regarding the cardiovascular risk factors that accompany PCOS, we found that macrovascular function has been assessed by flow-mediated dilatation (FMD), microvascular function by venous occlusion plethysmography (VOP), and arterial structure by ultrasonographic assessment of intima-media thickness (IMT) usually of the carotid artery. Contradictory results have been reported; however, in most studies, endothelial dysfunction, an early marker of atherosclerosis assessed either by haemodynamic methods such as FMD or by biochemical methods such as endothelin-1 levels, was found to be impaired. VOP is a less-studied method, with few indices altered. IMT was found to be altered in most of the included studies, but the population was more heterogeneous. Inflammatory markers, including C-reactive protein, were also found to be altered in most studies. On the other hand, a number of interventions have been shown beneficial for the markers of cardiovascular risk, in the context of insulin-sensitizers. However, other interventions such as oral contraceptive pills or statins did not consistently show a similar beneficial effect. In summary, the early identification and eventual treatment of cardiovascular clinical and biochemical risk factors may be used in clinical practice to prevent potential 'silent' triggers of cardiovascular disease.

Role of Receptor Profiling for Personalized Therapy in a Patient with a Growth Hormone-Secreting Macroadenoma Resistant to First-Generation Somatostatin Analogues.

BACKGROUND: Acromegaly is almost always caused by a pituitary adenoma and is associated with high morbidity and mortality when uncontrolled. Trans-sphenoidal removal of the adenoma is the mainstay of therapy, but fails to control the disease in a significant number of patients who require further treatment. Somatostatin analogues (SSAs) as monotherapy or in combination with growth hormone (GH)-receptor antagonists and/or dopamine agonists are used either alone or in combination following surgical failure to achieve disease control. The use of specific biomarkers may help to individualize the therapeutic plan after surgical failure and direct towards a more personalized approach. METHODS: We report a 41-year-old man with acromegaly and residual disease after repeated surgery that was resistant to first-generation SSAs. RESULTS: Biochemical and tumor control were achieved following the administration of a second-generation SSA, pasireotide, combined with pegvisomant, both at maximal doses and along with cabergoline. Histology specimens showed a sparsely-granulated GH-immunostaining pituitary adenoma with intense positivity for somatostatin receptors 2 and 5 and low levels of E-cadherin. CONCLUSION: Personalized medical therapy guided by currently available biomarkers, such as immunohistochemically-characterized receptor profiling or adhesion molecules, resulted in controlled insulin-like growth factor-1 (IGF-1) and GH levels and symptom alleviation following the combination of three drug-classes.

Differential Expression of Apoptotic and Low-Grade Inflammatory Markers in Alzheimer Disease Compared to Diabetes Mellitus Type 1 and 2.

BACKGROUND: Neuroinflammation, impaired brain insulin signaling, and neuronal apoptosis may be interrelated in the pathophysiology of people with Alzheimer disease (AD) and diabetes, either type 1 or 2 diabetes (T1D or T2D, respectively). METHODS: We studied 116 patients: 41 with AD, 20 with T1D, 21 with T2D, and 34 healthy controls. The number (n) of cytokine-secreting peripheral blood mononuclear cells (PBMCs) before and after mitogenic stimulation was determined for interleukin 1ß (IL1ß), interleukin 6 (IL6), tumor necrosis factor (TNF) by the enzyme-linked-immuno-spot assay. Serum concentrations of C-reactive protein (CRP) and Fas ligand (FASLG) were determined by ELISA. RESULTS: The studied subgroups did not differ in sex but differed in age. Higher CRP concentrations were detected in the AD group than in the T1D group (P = 0.02) and lower in controls (P < 0.001). The nPBMCs was higher in AD patients after stimulation than in basal conditions: after stimulation in nTNF (P < 0.001 vs T2D; P < 0.001 vs T1D; P = 0.001 vs control), nIL6 (P = 0.039 vs T2D; P < 0.001 vs T1D; P = 0.007 vs control), and nIL1ß (P = 0.03 vs control). The nPBMCs increased after stimulation with ΡΜA in all the subgroups (P < 0.001). FASLG in the AD group displayed statistically higher concentrations than in all other subgroups (P < 0.001 vs T2D; P < 0.001 vs T1D; P = 0.012 vs control). The nPBMCs was positively correlated with plasma concentrations of FASLG in the AD subgroup. CONCLUSIONS: Patients with AD display a low-grade systemic inflammation compared to people with diabetes. The FAS-FASLG pathway has a potential role because FASLG concentrations are positively correlated with the inflammatory response in AD. However, this positive correlation cannot be seen in people with diabetes, at least not with the apoptotic markers used in the present study.

The impact of financial crisis on coronary artery disease burden in Greece.

BACKGROUND: Economic crisis poses an immense threat to public health worldwide and has been linked to cardiovascular morbidity and mortality. Greece is facing a distinctive recession over the recent years. However, the exact impact on coronary artery disease (CAD) burden has not been adequately addressed. METHODS: Demographic, clinical, and angiographic data of 3895 hospitalized patients were retrospectively studied. Patients were classified into two groups: those before crisis (2006-2007, n = 1228) and those during crisis (2011-2015, n = 2667). RESULTS: All data before and during crisis were compared. During crisis, patients presented with less acute coronary syndrome (ACS - 45.5% vs. 39.9%, p < 0.001). Subsequently, there were more patients without CAD (23.7% vs. 35.1%, p < 0.001) or one-vessel disease (20.5% vs. 23%, p < 0.001). The prevalence of traditional risk factors decreased significantly or remained stable except obesity (26.3% vs. 31.4%, p = 0.002). A significant increase in the examined females (23.6% vs. 26.7%, p = 0.04) was also observed. CONCLUSIONS: The burden of CAD in Greece was partially affected during the financial crisis. Even though the incidence of ACS was decreased, more women and more patients with no- or single-vessel disease were referred for cardiac catheterization. In addition, the prevalence of traditional risk factors for CAD did not increase except obesity confirming the "obesity paradox." It seems that the impact of traditional risk factors for CAD is not an immediate process and is somewhat related to living conditions or other exogenous and social factors.

Effectiveness of artificial pancreas in the non-adult population: A systematic review and network meta-analysis.

OBJECTIVE: Artificial pancreas is a technology that minimizes user input by bridging continuous glucose monitoring and insulin pump treatment, and has proven safety in the adult population. The purpose of this systematic review and meta-analysis is to evaluate the efficacy of closed-loop (CL) systems in the glycemic control of non-adult type 1 diabetes patients in both a pairwise and network meta-analysis (NMA) context and investigate various parameters potentially affecting the outcome. METHODS: Literature was systematically searched using the MEDLINE (1966-2018), Scopus (2004-2018), Cochrane Central Register of Controlled Trials (CENTRAL) (1999-2018), Clinicaltrials.gov (2008-2018) and Google Scholar (2004-2018) databases. Studies comparing the glycemic control in CL (either single- or dual-hormone) with continuous subcutaneous insulin infusion (CSII) in people with diabetes (PWD) aged <18 years old were deemed eligible. The primary outcome analysis was conducted with regard to time spent in the target glycemic range. All outcomes were evaluated in NMA in order to investigate potential between-algorithm differences. Pairwise meta-analysis and meta-regression were performed using the RevMan 5.3 and Open Meta-Analyst software. For NMA, the package pcnetmetain R 3.5.1 was used. RESULTS: The meta-analysis was based on 25 studies with a total of 504 PWD. The CL group was associated with significantly higher percentage of time spent in the target glycemic range (Mean (SD): 67.59% (SD: 8.07%) in the target range and OL PWD spending 55.77% (SD: 11.73%), MD: -11.97%, 95% CI [-18.40, -5.54%]) and with lower percentages of time in hyperglycemia (MD: 3.01%, 95% CI [1.68, 4.34%]) and hypoglycemia (MD: 0.67%, 95% CI [0.21, 1.13%]. Mean glucose was also decreased in the CL group (MD: 0.75 mmol/L, 95% CI [0.18-1.33]). The NMA arm of the study showed that the bihormonal modality was superior to other algorithms and standard treatment in lowering mean glucose and increasing time spent in the target range. The DiAs platform was superior to PID in controlling hypoglycemia and mean glucose. Time in target range and mean glucose were unaffected by the confounding factors tested. CONCLUSIONS: The findings of this meta-analysis suggest that artificial pancreas systems are superior to the standard sensor-augmented pump treatment of type 1 diabetes mellitus in non-adult PWD. Between-algorithm differences are also addressed, implying a superiority of the bihormonal treatment modality. Future large-scale studies are needed in the field to verify these outcomes and to determine the optimal algorithm to be used in the clinical setting.

Prevalence, Incidence, and Contributors of Subclinical Atheromatosis, Arteriosclerosis, and Arterial Hypertrophy in HIV-Infected Individuals: A Single-Center, 3-Year Prospective Study.

Cardiovascular disease (CVD) is an important comorbidity for people living with HIV infection (PLWH) in the combined antiretroviral therapy era. We prospectively examined the presence of subclinical arterial disease in 138 consecutive CVD-free, HIV-infected individuals compared to 664 HIV-negative individuals. We studied 10 arterial sites in 4 beds using 5 distinct biomarkers of subclinical atheromatosis, arteriosclerosis, and hypertrophy and evaluated the association of subclinical arterial damage with CVD-related and HIV-related factors at baseline and at 3-year follow-up. Atheromatosis, arteriosclerosis, and arterial hypertrophy were present in 36.1%, 59.7%, and 34.3% of HIV-infected individuals, respectively, at baseline. HIV infection was independently associated with carotid atheromatosis and hypertrophy. The presence of carotid atheromatosis was independently associated with age, years of smoking, and exposure to nonnucleoside reverse transcriptase inhibitors (NNRTIs). The annual incidence of atheromatosis, arteriosclerosis, and arterial hypertrophy was 5.5, 18.6, and 12.5 cases/100 patients, respectively. Carotid atheromatosis progression was significantly associated with NNRTI exposure. People living with HIV infection exhibited high prevalence and incidence of subclinical arterial damage and site-specific predilection for the carotids. These investigations may help optimize HIV-specific CVD prediction models. The NNRTIs may contribute to atheromatosis, emphasizing the need to consider the atherogenic potential of antiretroviral drugs in management strategies.

Right and left common carotid arteries arising from the branchiocephalic, a rare variation of the aortic arch.

The aortic arch may present a plethora of anatomical variations, which my cause a cluster of complications in interventional procedures in surgery and angiography. We present a rare case of a common origin of both the common carotids arteries from the brachiocephalic trunk (anonymous artery), with the left common carotid artery emerging from the initial portion of it, forming a small common trunk. The great importance towards an excellent knowledge of the topographical aortic arch anatomy is stressed out.

Michael Constantine Psellus (1020-1105 AD) and his definition of strabismus.

Strabismus was a known eye misalignment since the Hippocratic era (ca 5th century BC). Hippocrates and his followers were the first to introduce the hypothesis of a hereditary condition. Many ancient Greek physicians like Galen (ca 2nd AD) provided several definitions, while Paul of Aegina (625-690 AD) was the scholar who introduced a method to treat it. Paul used a full face mask and an oil lamb to guide the eyeballs toward the desired direction. It seems that this approach endured for centuries to come. During 11th century AD in Constantinople, the Byzantine scholar and politician Michael Constantine Psellus (ca 1020-1105 AD) composed a series of philosophical, religious, political and scientific treatises. Among his work stands a medical iambic didactic poem of 1732 lines, in which he had mentioned strabismus. Although he was not an oculist, he had managed to define strabismus. His definition was noted as such, "Strabismus is caused by a spasm of the bodies which move (the eye balls) and the oblique tendency of the muscles". Psellus was aware of the knowledge of the past and recorded what was still valid at that era, presenting a memorable definition. As his reference was completely neglected from the medical bibliography, our study aims to add him in the scientific chain of those who understood this disorder. This study aims to compose Psellus biography, present ancient Greek and Byzantine ophthalmology's opinion concerning strabismus and note Psellus' definition. The TLG and MedLine/PubMed databases were searched and the terms "strabismus" and "Psellus" were used as key words.

Antithrombotic therapy in TAVI.

Transcatheter aortic valve implantation (TAVI) carries a significant thromboembolic and concomitant bleeding risk, not only during the procedure but also during the periprocedural period. Many issues concerning optimal antithrombotic therapy after TAVI are still under debate. In the present review, we aimed to identify all relevant studies evaluating antithrombotic therapeutic strategies in relation to clinical outcomes after the procedure. Four randomized control trials (RCT) were identified analyzing the post-TAVI antithrombotic strategy with all of them utilizing aspirin lifelong plus clopidogrel for 3-6 months. Seventeen registries have been identified, with a wide variance among them regarding baseline characteristics, while concerning antiplatelet therapy, clopidogrel duration was ranging from 3-12 months. Four non-randomized trials were identified, comparing single vs. dual antiplatelet therapy after TAVI, in respect of investigating thromboembolic outcome events over bleeding complications. Finally, limited data from a single RCT and a retrospective study exist with regards to anticoagulant treatment during the procedure and the optimal antithrombotic therapy when concomitant atrial fibrillation. In conclusion, due to the high risk and frailty of the treated population, antithrombotic therapy after TAVI should be carefully evaluated. Diminishing ischaemic and bleeding complications remains the main challenge in these patients with further studies to be needed in this field.

Colchicum Genus in the Writings of Ancient Greek and Byzantine Physicians.

The plants of the Colchicum family were known during the archaic period in Greece for their deleterious properties. Later on, they were used for the treatment of podagra. The treatment was introduced by the ancient Greek physicians and passed on to the Byzantine and Arabian physicians to endure until nowadays. The first plant was most probably named "Medea" from the notorious Colchican witch. As the most common member of the family blossoms in autumn, the plant was named Colchicum autumnale. Various nominations were also used, such as Ephemeron, Hermodactyl, Anima articulorum and Surugen. Our article discusses them, while at the same time presents the most notable authorities who have used Colchicum plants in herbal medicine and toxicology.

Mechanisms of pulse pressure amplification dipping pattern during sleep time: the SAFAR study.

The difference in pulse pressure (PP) between peripheral arteries and the aorta, called pulse pressure amplification (PPamp), is a well-described physiological phenomenon independently associated with cardiovascular events. Recent studies suggest that it exhibits circadian variability. Our aim was to detect the factors associated with the circadian variability of PPamp. In 497 consecutive subjects (aged 54 years, 56.7% male, 79.7% hypertensives), we assessed the circadian pattern of peripheral and central arterial hemodynamics by 24-hour evaluation of brachial and aortic blood pressure (BP), augmentation index (AI), and pulse wave velocity (PWV) using a validated oscillometric device (Mobil-O-Graph). All parameters exhibited a circadian variation. Sleep dipping (decrease) pattern was observed for PPamp, brachial and aortic systolic BP, mean BP, and PWV, whereas a rising pattern (higher sleep than wake values) was observed for brachial PP, aortic PP, and AI. The factors independently associated with the less sleep dipping in PPamp were older age, lower height, the use of antihypertensive medication, and sleep decrease in arterial stiffness (PWV), whereas female gender, the presence of hypertension, sleep increase of pressure wave reflections (AI), sleep decrease in heart rate, and mean BP were associated with a greater sleep-dipping in PPamp. These data provide further pathophysiological understanding of the mechanisms leading to PPamp dipping. Several implications regarding the clinical use of the aortic and brachial BP, especially during sleep time, are raised that should be addressed in future research.

Epilepsy, Theories and Treatment Inside Corpus Hippocraticum.

An archaic surgical procedure, the skull trepanning, was introduced in ancient Greece to treat brain derangement, and endured until the 18th century with the same use. Hippocrates recognized epilepsy as a common entity and categorized it as a brain disorder, removing any divine origin. He proposed that the excess of black bile and mucus is due to the infiltration of air inside the blood circulation (veins). For him it was a hereditary disease that could be cured. Thus, he suggested a non-invasive treatment based on herbal potions, and a surgical treatment by using the most advanced operation of the era, the open brain drilling, known as trepanning, or trephination, setting the beginning of neurosurgery.

Antiepileptic Treatment Strategy in Vascular Malformations.

BACKGROUND: Antiepileptic treatment strategy plays an important role in the management of intracranial vascular malformations. The intracranial vascular malformations can be divided into cavernous hemangiomas, arteriovenous malformations, developmental venous anomalies and capillary telangiectasias. Seizures and hemorrhage are among their most common clinical manifestations. OBJECTIVE: The aim of this article is to review the current literature on the antiepileptic treatment in the setting of intracranial vascular malformations and offer an updated view on when antiepileptic drug treatment should be employed for each type of vascular malformation. METHODS AND MATERIALS: Current literature has been reviewed on cavernous malformations, arteriovenous malformations, developmental venous anomalies and capillary telangiectasias. Epidemiological features, epileptogenesis, clinical presentation and antiepileptic treatment have been analyzed. RESULTS: A variety of treatment modalities exist for the management of intracranial vascular malformations, including antiepileptic treatment, microsurgery, radiosurgery and embolization. The decision-making process is different for each type of intracranial vascular malformation. Moreover, a plethora of other clinical factors needs to be taken into consideration during the decision-making process, such as the patient's age and comorbidities, the risk of hemorrhage the need for definitive treatment of the malformation, the seizure rates after the definitive treatment, the efficacy and side effects profile of antiepileptic drugs. CONCLUSION: Antiepileptic treatment strategy is a multifactorial decision that should be individualized and ideally be made by multidisciplinary teams.

Hallmarks in history of esophageal carcinoma.

Esophageal cancer is one of the deadliest cancers due to its aggressive behavior and poor survival. It was mentioned in the works of ancient Chinese and Arabo-islamic physicians, centuries before the recognition of high incidence in the Asian esophageal cancer belt. Till the 19th century the disease was considered incurable and the main goal of the proposed treatments was to alleviate dysphagia and pain. The introduction of esophagoscope in 1868 by Adolf Kussmaul (1822-1902) contributed to the observation of the living esophagus and to the diagnosis of esophageal pathologies, paving the way for new therapeutic approaches. In 1877, Vincenz Czerny (1842-1916) performed the first successful resection of the cervical esophagus for carcinoma, followed by Franz Torek (1861-1938) who carried out in 1913 the first successful subtotal thoracic esophagectomy and Tohru Ohsawa (1882-1984) who performed the world's first esophagectomy with an intrathoracic esophagogastric anastomosis. Nowadays, despite the advent of biomedical technology and the development of operation techniques, the surgical treatment of esophagus still remains a challenge.

Concomitant alterations of metabolic parameters, cardiovascular risk factors and altered cortisol secretion in patients with adrenal incidentalomas during prolonged follow-up.

OBJECTIVE: Adrenal incidentalomas (AI) are associated with metabolic and hormonal abnormalities, most commonly autonomous cortisol secretion (ACS). Data regarding alterations of insulin resistance (IR) and ACS after prolonged follow-up are limited. We investigated the evolution of IR, cortisol secretion and ACS development in patients with AI during prolonged follow-up. DESIGN: Prospective study in a tertiary hospital. PATIENTS AND MEASUREMENTS: Seventy-one patients with AI [51 nonfunctioning (NFAI) and 20 ACS] and 5·54 ± 1·7 years follow-up underwent testing for ACS and oral glucose tolerance test to determine IR indices and adrenal imaging. RESULTS: At follow-up, 16/51 (31%) NFAI patients converted to ACS, while two with previous ACS reverted to NFAI; 21% (7/33) of patients who did not covert to ACS exhibited high urinary-free cortisol (H-UFC) levels. All AI patients developed deterioration of IR irrespective of their cortisol secretory status. Eight patients developed newly diagnosed type 2 diabetes (9·8% NFAI and 15% ACS, respectively) and 14 IR (17·6% NFAI and 25% ACS, respectively). Adenoma size increased from 2·1 ± 0·8 to 2·3 ± 0·8 cm, whereas IR correlated with postdexamethasone cortisol level and adenoma size increase. IR showed an incremental continuum trend from normal UFC (Ν-UFC), to H-UFC, C-ACS and ACS patients. CONCLUSIONS: New-onset ACS developed in 31% patients with NFAI, whereas 21% of NFAI patients had H-UFC levels. All AI patients as a group and the subgroups of N-UFC, H-UFC, C-ACS and ACS patients developed deterioration of metabolic parameters during follow-up that was more prominent in ACS patients.