Aggressive PitNETs and Potential Target Therapies: A Systematic Review of Molecular and Genetic Pathways

Recently, advances in molecular biology and bioinformatics have allowed a more thorough understanding of tumorigenesis in aggressive PitNETs (pituitary neuroendocrine tumors) through the identification of specific essential genes, crucial molecular pathways, regulators, and effects of the tumoral microenvironment. Target therapies have been developed to cure oncology patients refractory to traditional treatments, introducing the concept of precision medicine. Preliminary data on PitNETs are derived from preclinical studies conducted on cell cultures, animal models, and a few case reports or small case series. This study comprehensively reviews the principal pathways involved in aggressive PitNETs, describing the potential target therapies. A search was conducted on Pubmed, Scopus, and Web of Science for English papers published between 1 January 2004, and 15 June 2023. 254 were selected, and the topics related to aggressive PitNETs were recorded and discussed in detail: epigenetic aspects, membrane proteins and receptors, metalloprotease, molecular pathways, PPRK, and the immune microenvironment. A comprehensive comprehension of the molecular mechanisms linked to PitNETs' aggressiveness and invasiveness is crucial. Despite promising preliminary findings, additional research and clinical trials are necessary to confirm the indications and effectiveness of target therapies for PitNETs.

UNet and MobileNet CNN-based model observers for CT protocol optimization: comparative performance evaluation by means of phantom CT images

Purpose

The aim of this work is the development and characterization of a model observer (MO) based on convolutional neural networks (CNNs), trained to mimic human observers in image evaluation in terms of detection and localization of low-contrast objects in CT scans acquired on a reference phantom. The final goal is automatic image quality evaluation and CT protocol optimization to fulfill the ALARA principle.

Approach

Preliminary work was carried out to collect localization confidence ratings of human observers for signal presence/absence from a dataset of 30,000 CT images acquired on a PolyMethyl MethAcrylate phantom containing inserts filled with iodinated contrast media at different concentrations. The collected data were used to generate the labels for the training of the artificial neural networks. We developed and compared two CNN architectures based respectively on Unet and MobileNetV2, specifically adapted to achieve the double tasks of classification and localization. The CNN evaluation was performed by computing the area under localization-ROC curve (LAUC) and accuracy metrics on the test dataset.

Results

The mean of absolute percentage error between the LAUC of the human observer and MO was found to be below 5% for the most significative test data subsets. An elevated inter-rater agreement was achieved in terms of S-statistics and other common statistical indices.

Conclusions

Very good agreement was measured between the human observer and MO, as well as between the performance of the two algorithms. Therefore, this work is highly supportive of the feasibility of employing CNN-MO combined with a specifically designed phantom for CT protocol optimization programs.

Discretized superimposed optical fiber long-period gratings

A novel technique, to the best of our knowledge, for the inscription of superimposed long-period gratings with arbitrary grating pitches is proposed and experimentally validated. The technique is based on the discretization of an ideal continuous sinusoidal refractive index (RI) pattern with a step function. The RI variation is induced by means of the irradiation of a photosensitive fiber with a 248 nm UV laser beam. The nonlinear relation between the induced RI change and the UV fluence was experimentally derived. Two superimposed long-period grating (LPGs) with different grating pitches have been realized with the discretization technique; the transmission spectrum was compared with that of two superimposed LPGs obtained with the traditional square wave RI modulation. The validity of the proposed technique was demonstrated by the better spectral characteristics of the discretized superimposed LPGs.

Characterization of Physicians Workload in a Reference Center for the Treatment of Thrombotic and Bleeding Disorders

Heavy workloads in healthcare have been often associated to adverse clinical outcomes. To reduce workloads, an optimal scheduling of clinical staff resources is not enough, but particular attention must be payed to work organization and task characteristics. Moreover, interruptions during the clinical practice contribute to increase perceived workloads. In this study we analyzed and characterized the physicians' workload in an Italian center for the treatment of thrombotic and bleeding disorders. First, all clinical and administrative processes performed in the center were analyzed by means of two process modelling tools. Then, the quantification of the physicians' workload and the characterization of interruptions during practice were conducted. From our results it emerged that the task that mainly impacts on the workload is ambulatory care (42% of total workload) while interruptions produce a delay of almost 15 minutes per day and mainly occur during visits. Including all activities, the total daily workload per physician was 8 hours on average. In this time breaks were not taken into account. Concluding, from our analysis it is evident that the physicians' workload in the analyzed center is heavy and interruptions represent a source of delay in the workflow, that impact the physicians' workload.

Reducing perioperative blood loss in patients undergoing total hip arthroplasty

In this prospective, randomised, double-blind study, we investigated the effect of epidural anaesthesia and an antifibrinolytic agent, Aprotinin (500,000 KIU in bolus before surgery and 500,000 KIU h-1 in drip form during surgery), on intra and postoperative blood loss and transfusion requirements in total hip arthroplasty. Sixty patients were allocated randomly to four groups (A: epidural + general anesthesia + Aprotinin, B: epidural + general anesthesia + placebo (equal volume), C: general anaesthesia + Aprotinin, D: general anaesthesia + placebo). Postoperative analgesia: epidural analgesia in groups A and B, systemic analgesia with opiates in groups C and D.

Blood loss during surgery was monitored and salvaged with the Compact-A Dideco, and postoperative blood loss with the BT 797 Recovery Dideco for the first 24 hours. Perioperative blood loss, frequency and quantity of transfusions were significantly higher in group D (p < 0.0001). Total blood loss was reduced by 31.3% by epidural anaesthesia, 20.4% by Aprotinin and 51.4% using a combination of the two techiniques.

Adaptive response of the rat pancreas to dietary substrates: parallel regulation of trypsinogen and pancreatic secretory trypsin inhibitor

Chronic pancreatitis has been associated with malnutrition in alcoholic patients and malnourished juveniles. The composition of the diet, especially the protein content, regulates the synthesis of secretory proteins in the rat pancreas. Adaptive responses of the pancreas have shown that anionic proteases (e.g., trypsinogen) are upregulated during protein deprivation. We hypothesize that the (cationic) pancreatic secretory trypsin inhibitor (PSTI) is down-regulated after a protein-deficient diet. Low PSTI levels might cause a lack of protection from prematurely activated trypsin and therefore enhance the risk for pancreatic inflammation. Over a period of 1 month, rats were fed one of four isocaloric diets with a casein content varying from 0 to 82%. PSTI and trypsinogen mRNA remained fairly constant, irrespective of the diet composition. Trypsinogen and elastase secreted into pancreatic juice were upregulated after a protein-deficient diet relative to a control diet. Contrary to our hypothesis, PSTI was also upregulated. Parallel secretion of trypsinogen and PSTI appears to ensure protection against premature activation even under extreme dietary conditions.

Regulation of PSP/reg in rat pancreas: immediate and steady-state adaptation to different diets

Pancreatic stone protein/reg protein (PSP/reg) is a secretory pancreatic protein of hitherto unknown function. It is precursor to a spontaneously precipitating peptide called pancreatic thread protein, which is found in protein plugs within the pancreatic ductal system. Increasing PSP/reg concentrations in pancreatic juice might augment the risk of intraductal plug formation and therefore be a condition predisposing to chronic pancreatitis. Malnutrition is associated with a high incidence of chronic pancreatitis in tropical countries. In a diet study with rats, we tested the hypothesis that protein malnutrition leads to increased PSP/reg concentrations in pancreatic juice. A highly sensitive and reliable enzyme-linked immunosorbent assay (ELISA) for rat PSP/reg was newly established. Male Sprague-Dawley rats were allocated to three nearly isocaloric experimental diets, which contained 0, 45, or 82% casein, respectively, or to a control diet (22% casein). We evaluated PSP/reg expression under these four dietary conditions on the RNA and on the protein level, performing a time-course study over a period of 28 days. Our results demonstrate that PSP/reg expression is not increased because of a protein-deficient diet if investigated under steady-state conditions. After a temporary increase in PSP/reg levels due to a carbohydrate-deficient high-protein diet, we could not find signs of a diet-dependent regulation of this protein. The regulation of PSP/reg thus differs from that of most other pancreatic secretory proteins. Our findings contradict earlier reports that had drawn conclusions based solely on messenger RNA levels.

[Acute pulmonary edema from contrast media. A clinical case]

A rare and strong adverse reaction to contrast media (mdc) i.v. injected to carry out an abdominal vessels' angiography is reported. The patient suffered from non cardiogenic pulmonary edema and hypoxia. Chest X-ray detected the same radiological patterns of ARDS: in contrast alveolar edema became insignificant in 5 days. Serum immunocomplexes levels were high in the early phase of the reaction. Serum IgE, C3 and C4 were within the normal ranges. The case can be considered strongly significative because of the rarity of this syndrome; moreover, the early monitoring detected some data which could contribute to the knowledge of the physiopathology of contrast media adverse reaction. Overall, the presence of an immunological disease can increase the risk for adverse reactions to contrast media.

Reducing perioperative blood loss in patients undergoing total hip arthroplasty

In this prospective, randomised, double-blind study, we investigated the effect of epidural anaesthesia and an antifibrinolytic agent, Aprotinin (500,000 KIU in bolus before surgery and 500,000 KIU h(-1) in drip form during surgery), on intra and postoperative blood loss and transfusion requirements in total hip arthroplasty. Sixty patients were allocated randomly to four groups (A: epidural + general anesthesia + Aprotinin, B: epidural + general anesthesia + placebo (equal volume), C: general anaesthesia + Aprotinin, D: general anaesthesia + placebo). Postoperative analgesia: epidural analgesia in groups A and B, systemic analgesia with opiates in groups C and D. Blood loss during surgery was monitored and salvaged with the Compact-A Dideco, and postoperative blood loss with the BT 797 Recovery Dideco for the first 24 hours. Perioperative blood loss, frequency and quantity of transfusions were significantly higher in group D (p<0.0001). Total blood loss was reduced by 31.3% by epidural anaesthesia, 20.4% by Aprotinin and 51.4% using a combination of the two techniques.

Reducing Perioperative Blood Loss in Patients Undergoing Total Hip Arthroplasty

In this prospective, randomised, double-blind study, we investigated the effect of epidural anaesthesia and an antifibrinolytic agent, Aprotinin (500,000 KIU in bolus before surgery and 500,000 KIU h-1 in drip form during surgery), on intra and postoperative blood loss and transfusion requirements in total hip arthroplasty. Sixty patients were allocated randomly to four groups (A: epidural + general anesthesia + Aprotinin, B: epidural + general anesthesia + placebo (equal volume), C: general anaesthesia + Aprotinin, D: general anaesthesia + placebo). Postoperative analgesia: epidural analgesia in groups A and B, systemic analgesia with opiates in groups C and D.

Blood loss during surgery was monitored and salvaged with the Compact-A Dideco, and postoperative blood loss with the BT 797 Recovery Dideco for the first 24 hours. Perioperative blood loss, frequency and quantity of transfusions were significantly higher in group D (p < 0.0001). Total blood loss was reduced by 31.3% by epidural anaesthesia, 20.4% by Aprotinin and 51.4% using a combination of the two techiniques.

Fructose and tagatose protect against oxidative cell injury by iron chelation

To further investigate the mechanism by which fructose affords protection against oxidative cell injury, cultured rat hepatocytes were exposed to cocaine (300 microM) or nitrofurantoin (400 microM). Both drugs elicited massively increased lactate dehydrogenase release. The addition of the ketohexoses D-fructose (metabolized via glycolysis) or D-tagatose (poor glycolytic substrate) significantly attenuated cocaine- and nitrofurantoin-induced cell injury, although both fructose and tagatose caused a rapid depletion of ATP and compromised the cellular energy charge. Furthermore, fructose, tagatose, and sorbose all inhibited in a concentration-dependent manner (0-16 mM) luminolenhanced chemiluminescence (CL) in cell homogenates, indicating that these compounds inhibit the iron-dependent reactive oxygen species (ROS)-mediated peroxidation of luminol. Indeed, both Fe2+ and Fe3+ further increased cocaine-stimulated CL, which was markedly quenched following addition of the ketohexoses. The iron-independent formation of superoxide anion radicals (acetylated cytochrome c reduction) induced by the prooxidant drugs remained unaffected by fructose or tagatose. The iron-chelator deferoxamine similarly protected against prooxidant-induced cell injury. In contrast, the nonchelating aldohexoses D-glucose and D-galactose did not inhibit luminol CL nor did they protect against oxidative cell injury. These data indicate that ketohexoses can effectively protect against prooxidant-induced cell injury, independent of their glycolytic metabolism, by suppressing the iron-catalyzed formation of ROS.

[A clinical case of pulmonary thromboembolism in a patient at risk treated with rt-pA]

After a brief mention of new advances in the pathophysiology of fibrinolysis, the authors outline the pharmacological properties of the new thrombolytic agent rt-pA versus classic thrombolytic agent urokinase and streptokinase. Thereafter they report a case of acute pulmonary embolism with severe hypoxemia in a patient with a history of recent traumatic cerebral bleeding. Thrombolytic treatment with rt-pA (100 mg/2 h) resulted in a satisfactory clinical outcome without appreciable worsening of intracranial injury.