Striving for Uniformity: A Review on Advances and Challenges To Achieve Uniform Polyethylene Glycol

Poly(ethylene glycol) (PEG) is the polymer of choice in drug delivery systems due to its biocompatibility and hydrophilicity. For over 20 years, this polymer has been widely used in the drug delivery of small drugs, proteins, oligonucleotides, and liposomes, improving the stability and pharmacokinetics of many drugs. However, despite the extensive clinical experience with PEG, concerns have emerged related to its use. These include hypersensitivity, purity, and nonbiodegradability. Moreover, conventional PEG is a mixture of polymers that can complicate drug synthesis and purification leading to unwanted immunogenic reactions. Studies have shown that uniform PEGylated drugs may be more effective than conventional PEGylated drugs as they can overcome issues related to molecular heterogeneity and immunogenicity. This has led to significant research efforts to develop synthetic procedures to produce uniform PEGs (monodisperse PEGs). As a result, iterative step-by-step controlled synthesis methods have been created over time and have shown promising results. Nonetheless, these procedures have presented numerous challenges due to their iterative nature and the requirement for multiple purification steps, resulting in increased costs and time consumption. Despite these challenges, the synthetic procedures went through several improvements. This review summarizes and discusses recent advances in the synthesis of uniform PEGs and its derivatives with a focus on overall yields, scalability, and purity of the polymers. Additionally, the available characterization methods for assessing polymer monodispersity are discussed as well as uniform PEG applications, side effects, and possible alternative polymers that can overcome the drawbacks.

The role of shame in the relationship between bullying and self-harm in portuguese adolescents

Introduction

Bullying consists in acts of intentional and repeated physical or psychological violence, completed by an individual or a group of individuals, provoking pain, distress and shame. Currently, it is considered a serious problem with health implications in adolescents. Shame is a self-conscious, multifaceted and socially focused emotion that relates to a negative self-assessment.

Objectives

The study aim was to investigate the mediating role of Shame in the relationship between Bullying and Self-harm and Suicide Ideation in Portuguese adolescents.

Methods

346 adolescents (58.4% girls), aged 15.32±1.193 from public and private schools (9^th to 12^th grades) in Coimbra, answered the validated Portuguese versions of the Bullying Questionnaire, the Other as Shame Scale for Adolescents and the Self-Harm and Suicidal Ideation Questionnaire. For data analysis the SPSS 26 and Macro Process (Hayes 2020) was used.

Results

Bullying Victimization had a prevalence of 18.78%. Girls and boys significantly differ in Bullying Victimisation, Self-Harm, Suicidal Ideation and Shame mean scores (all p<.05). In girls, Bullying Victimisation was correlated with Shame and Suicidal Ideation. The mediation analysis showed that, in girls, Shame partially mediated the relationship between Bullying and Suicidal Ideation (p<.001). We didn’t find these results in boys.

Conclusions

Bullying is a global problem that needs to be addressed. Adolescents of today are the adults of tomorrow. In a physical growth and mental maturation phase, it is urgent to avoid disruptors which lead to psychopathology. Our results corroborate that Shame can be a harmful factor in Bullying with deleterious consequences in adolescents.

Habits and quality of life in portuguese girl adolescents: Association with psychological disturbance distress

Introduction

Adolescence is a life period with considerable biological, psychological and social changes. Quality of life is a complex and multifactorial construct that necessarily encompasses the adolescent’s mental well-being. Some life habits like sleep, sport practice and screen time can be either risk factors or protective factors, influencing the quality of life and mental health.

Objectives

To investigate the role of sleep habits, sport practice and screen time in quality of life, and psychological distress in a Portuguese adolescent girl sample.

Methods

409 girls, mean aged 13.51±2.298, from public and private schools in Coimbra answered questions about sleep time, sport practice and screen time habits; the Portuguese versions of the Quality of Life Questionnaire (reduced version) and theAnxiety, Depression and Stress Scale. SPSS 26 was used.

Results

Girls mentioned to sleep 8,2 hours/night during the week and 9,4 hours/night at the weekend. They spend 1,5 hours/day during the week and 1,8 hours/day at the weekend with Screens. They spend 2,1 hours/ week in Sport Practice. Quality of Life was positive correlated with Sleep Time and negative correlated with Screen Time, Anxiety, Depression and Stress (all p<.05). Multiple regression analysis showed that Screen Time, Anxiety and Depression were all significant predictors of Quality of life in girls (p<0,05).

Conclusions

Our findings show that Screen Time is related with poor Quality of Life in girls. These results suggest the importance of addressing Screen Time and Psychological Distress in adolescent girls during adolescent health care consults.

Further validation of the internet addiction test: Psychometric characteristics in a portuguese university sample

Introduction

The Internet Addiction Test (IAT) is a 20-item, self-reported questionnaire that measures the presence and severity of Internet addiction which is an increasing problem in adolescents. Although a Portuguese version IAT has been validated in adults, its psychometric properties have never been evaluated before, in adolescents.

Objectives

To analyse the reliability and construct and concurrent validity of the IAT in a Portuguese adolescent sample.

Methods

772 adolescents (53.5% girls), mean aged 13.21±2.246, answered the Portuguese versions of the IAT and the Portuguese versions of validated scales to evaluate: Cyberbullying, Game Addiction, Agressivity and Anxiety, Depression Scales. To study the temporal stability, 377 (60.5% girls) respondents answered the questionnaires again after approximately four-six weeks. The total sample was aleatory splitted to realize the exploratory and the confirmatory factor analyses.

Results

Exploratory and confirmatory factor analyses supported a second order two-factor structure - “Isolation and Social Commitment” and F2-“Negligence and Functional Commitment”. The χ2/df value was 2.260 and had a significant p value; it had the lowest RMSEA score = .074 (p< .001) and it had the highest TLI (.980) and CFI (.905). IAT mean scores were no different between genders [Girls=29.25±18.775 vs. Boys: 30.85±17.929, p=.405]. The Cronbach’s alphas were > .85. Pearson correlation between the test and the re-test was r=.660. The IAT, video game addiction (r=.434), Cyberbullying (r=.383), anxiety (r=.209) and depression (r=.263) were significantly correlated (p<.001).

Conclusions

The Portuguese IAT has good reliability and validity, showing to be an adequate instrument for measuring Internet Addiction symptoms in Portuguese Adolescents.

Malabsorption syndrome as a rare cause of nephrocalcinosis

Nephrocalcinosis is characterized by calcification of kidney parenchyma and can be caused by an increased amount of calcium, phosphate or oxalate in urinary excretion. We report a 35-year-old female with nephrocalcinosis. She had fitful steatorrhea since last year. Physical examination was normal. Analytic exams found normal renal function and ionogram. Primary hyperparathyroidism, renal tubular acidosis and sarcoidosis were excluded. Urinalysis showed mild hematuria, without proteinuria and 24-hour urine collection exhibited hyperoxaluria. Patient was submitted to an endoscopy and duodenal biopsy whose histology sustained the diagnosis of celiac disease. Fluid intake increase and gluten and oxalate free diet were initiated.

Detection of new pathogenic mutations in patients with congenital haemolytic anaemia using next-generation sequencing

INTRODUCTION

Congenital haemolytic anaemia (CHA) refers to a group of genetically heterogeneous disorders, mainly caused by changes in genes encoding globin chains, cytoskeletal proteins and red cell enzymes, in which accurate diagnosis can be challenging with conventional techniques.

METHODS

To set-up a comprehensive assay for detecting mutations that could improve aetiological diagnosis, we designed a custom panel for sequencing coding regions from 40 genes known to be involved in the pathogenesis of CHA, using the Ion Torrent^™ (Thermo Fisher Scientific, S.L. Waltham, MA, USA) Personal Genome Machine (PGM) Sequencer. A control group of 16 samples with previously known mutations and a test group of 10 patients with unknown mutations were included for assay validation and application, respectively.

RESULTS

In the test group, we identified pathogenic mutations in all cases: four patients had novel mutations in genes related to membrane defects (SPTB, ANK1, SLC4A1 and EPB41), four were homozygous or compound heterozygous for mutations in genes related to enzyme deficiencies (GPI, TPI1 and GSS), one had a mutation in the HBB gene and another presented a homozygous mutation in the ADAMTS13 gene.

CONCLUSIONS

Ion PGM sequencing with our custom panel is a highly efficient way to detect mutations causing haemolytic anaemia, including new variations. It is a high-throughput detection method that is ready for application in clinical laboratories.

Liver retransplantation in patients with acquired familial amyloid polyneuropathy: a Portuguese center experience

In 1995 Furtado et al performed the first domino transplantation using a donor liver with familial amyloid polyneuropathy (FAP), thereby increasing the pool of donors. Our experience showed that the onset of FAP symptoms occurs earlier in some patients. Patients with FAP acquired by transplantation are candidates for liver retransplantation to minimize the progression of symptoms. Liver retransplantation is considered to be a high-risk procedure and has lower survival compared with the first transplantation. We evaluated the risk of liver retransplantation in patients with acquired FAP. We did a retrospective analysis of these patients based on the records of perioperative data. From 1995 to 2004 we carried out 81 domino transplantations, of which 10 were submitted to liver retransplantation because of acquired FAP. The better outcomes in this group lead us to think that the liver retransplantation in patients with acquired FAP is not associated with the same risks of liver retransplantation in candidates with graft failure.

Evaluation of operative risk in de novo familial amyloid polyneuropathy retransplantation

Familial amyloid polyneuropathy (FAP) is the most common hereditary amyloidosis, characterized by progressive peripheral sensory and motor neuropathy. The livers of patients with FAP are used in domino liver transplantation in selected cases to increase the number of grafts available. In our department 10 patients underwent liver retransplantation (ReLTx) in the absence of liver dysfunction by de novo FAP after domino liver transplantation. Our aim was to compare the differences in the consumption of blood products and intraoperative hemodynamic support among patients with FAP undergoing liver transplantation (LTx) and patients with de novo FAP undergoing ReLTx in the same time frame. The anesthetic records of all patients who underwent LTx for FAP and ReLTx for de novo FAP were analyzed, from January 2009 to May 2014. Patients were divided into 2 groups: group 1 patients with FAP, and group 2 patients with de novo FAP. Statistical differences in the value of preoperative creatinine were found. Hemoglobin levels, preoperative international normalized ratio (INR), use of blood products, aminergic support, and surgical time showed no statistical difference. Major bleeding rates would be expected in patients undergoing ReLTx. Changes in renal function, chronic immunosuppressive therapy, and age may contribute to the increase in intraoperative complications. We did not find statistically significant differences, leading us to the conclusion that de novo FAP does not seem to be a predictor of perioperative risk.

Variants of the serotonin transporter gene (SLC6A4) significantly contribute to hyperserotonemia in autism

The role of the serotonin system in the etiology and pathogenesis of autism spectrum disorders (ASD) is not clearly defined. High levels of platelet serotonin (5-HT) have been consistently found in a proportion of patients, and it is known that specific 5-HT transporter gene (SLC6A4) variants modulate transporter reuptake function, therefore possibly influencing the occurrence of hyperserotonemia in a subset of autistic patients. We have examined the association of platelet serotonin levels with two SLC6A4 polymorphisms, 5-HTT gene-linked polymorphic region (HTTLPR) in the promoter and intron 2 variable number of tandem repeats (VNTR), in a sample of 105 ASD patients, their parents, and 52 control children. Quantitative transmission disequilibrium test (QTDT) results showed a significant effect on 5-HT levels of each SLC6A4 marker (P=0.017 for HTTLPR; P=0.047 for intron 2 VNTR) and of haplotypes of the two markers (P=0.017), with a major contribution of the L.Stin2.10 haplotype (P=0.0013). A 5-HT mean value in the range of hyperserotonemia was associated with the homozygous L.Stin2.10 haplotype (H (1,N=97)=7.76, P=0.0054), which occurred in 33% of hyperserotonemic patients against 6% of patients with normal 5-HT levels (Fisher's exact test: P=0.013, OR=8). Allele interaction at the HTTLPR locus was found, with a significant dominance variance effect on 5-HT levels. We found no transmission disequilibrium of any of the SLC6A4 variants in ASD. Our results show that the SLC6A4 gene is a significant factor in the determination of 5-HT levels, and that specific SLC6A4 variants are associated with an increased risk for hyperserotonemia in our sample of autistic patients. The biological mechanism, however, is unlikely to involve the SLC6A4 gene solely. The associated SLC6A4 alleles likely interact with other genes or environmental factors to produce the abnormally high 5-HT levels observed in this subset of autistic patients, who possibly represent a separate etiological group.

[Malformations in cortical development in patients with epilepsy. Neuroimaging of 17 cases]

This article reviews Malformations of Cortical Development (MCD) diagnosed by Magnetic Resonance Imaging (MRI) in a series of patients with epilepsy. This study spans a five year period. The frequency of these malformations was 7.1%. Most of these were focal or multifocal and the most common ones were polymicrogyria (35.3% of the patients), heterotopia (29.4%), and focal cortical dysplasia (29.4%). The frontal lobes were the most frequently affected regions. The various MCD encountered reflect the wide spectrum of MCD leading to epilepsy.

Haemodynamics during liver transplantation in familial amyloidotic polyneuropathy: study of the intraoperative cardiocirculatory data of 50 patients

BACKGROUND

Circulatory instability frequently complicates liver transplantation for familial amyloidotic polyneuropathy (FAP) and may be a source of surgical morbidity and mortality.

OBJECTIVE

To evaluate FAP intraoperative haemodynamic data and their relation to the duration of surgery, and need for anaesthetic drugs. RBC and sympathomimetic amines.

SETTING

Clinical study during a four year period. PATIENTS (mean +/- SD): Group I included 50 consecutive FAP ATTR Met 30 recipients of first transplantation. Age was 35.3 +/- 7.1 years, neurological score 34.3 +/- 13 in 100 and time elapsed from first symptom 5.0 +/- 2.7 years. Group II (control), not different concerning age and sex, included 51 patients transplanted during the same period with other pathologies.

METHOD

Anaesthetic protocol, monitoring and surgical techniques were similar in both groups. Data of the two groups were compared either by the Student's t-test or Fisher's exact test.

RESULTS

Low values of systemic vascular resistance index were observed in both groups, with no differences between them. Systemic arterial pressures were usually lower in group I, because cardiac index and heart rate were also significantly lower, although within normal values. However, in group I, isoflurane (a vasodilator anaesthetic) was used during less time (p < 0.05) and in lower concentrations (p < 0.01) and phenylephrine was necessary in 26% of patients vs 0 patients in group II (p < 0.001).

CONCLUSION

FAP patients presented a different intraoperative behaviour when compared to other patients submitted to liver transplantation. From a clinical point of view, the authors stress: 1--As a result of autonomic dysfunction, the administration of anaesthetic drugs to FAP patients always presents the risk of producing significant hypotension; even the use of ketamine does not prevent hypotension; 2--Safety is ensured by beat-to-beat surveillance of arterial pressures and the capacity to act immediately to support circulation; 3--These patients seem to be very sensitive to decreases in the pre-load; 4--Hypotension is also frequent with an adequate pre-load, usually as the result of low SVR; an infusion of a vasoconstrictor drug emerges as the most frequent treatment requested and our experience supports it as an effective one.

Serum potassium concentrations after suxamethonium in patients with familial amyloid polyneuropathy type I

BACKGROUND

Suxamethonium produces an abnormal increase in serum potassium in some neurological diseases and some authors have suggested that it is safer not to use this drug in patients with familial amyloid polyneuropathy (FAP). However, there are no data previously reported to support this hypothesis. The aim of this study was to evaluate the magnitude of the potassium increase produced by suxamethonium in FAP type I.

METHOD

Twenty-one FAP Met 30 patients anaesthetised for liver transplantation were studied. Age was 34.9 +/- 6.9 years (mean +/- SD), time elapsed from first symptom 5.5 +/- 3.2 years and weight was 14 +/- 9% below ideal body weight. Anaesthesia was induced with thiopentone and low-dose fentanyl. Samples for blood gas and 5 min after 1 mg/kg of suxamethonium was given for tracheal intubation.

RESULTS

Before induction serum potassium levels were 3.8 +/- 0.4 mmol/L. One minute after suxamethonium, values were 3.8 +/- 0.4 mmol/L and 5 min after 4.3 +/- 0.5 mmol/L. The maximal increase observed was 1.6 mmol/L (from 3.4 mmol/L to 5.0 mmol/L).

CONCLUSION

The average increase in plasma potassium concentrations observed in FAP patients after suxamethonium was similar to the increase observed in a normal population by others. Our study can exclude the hypothesis that an anomalous increase in potassium would be a typical and frequent response to suxamethonium in FAP met 30 patients. However, we cannot exclude that a dangerous rise in serum potassium may exist in a certain percentage of FAP patients.