Estimation of amyloid distribution by [ 18 F]flutemetamol PET predicts the neuropathological phase of amyloid β-protein deposition

Abstract

The deposition of the amyloid β-protein (Aβ) in senile plaques is one of the histopathological hallmarks of Alzheimer's disease (AD). Aβ-plaques arise first in neocortical areas and, then, expand into further brain regions in a process described by 5 phases. Since it is possible to identify amyloid pathology with radioactive-labeled tracers by positron emission tomography (PET) the question arises whether it is possible to distinguish the neuropathological Aβ-phases with amyloid PET imaging. To address this question we reassessed 97 cases of the end-of-life study cohort of the phase 3 [¹⁸F]flutemetamol trial (ClinicalTrials.gov identifiers NCT01165554, and NCT02090855) by combining the standardized uptake value ratios (SUVRs) with pons as reference region for cortical and caudate nucleus-related [¹⁸F]flutemetamol-retention. We tested them for their prediction of the neuropathological pattern found at autopsy. By defining threshold levels for cortical and caudate nucleus SUVRs we could distinguish different levels of [¹⁸F]flutemetamol uptake termed PET-Aβ phase estimates. When comparing these PET-Aβ phase estimates with the neuropathological Aβ-phases we found that PET-Aβ phase estimate 0 corresponded with Aβ-phases 0-2, 1 with Aβ-phase 3, 2 with Aβ-phase 4, and 3 with Aβ-phase 5. Classification using the PET-Aβ phase estimates predicted the correct Aβ-phase in 72.16% of the cases studied here. Bootstrap analysis was used to confirm the robustness of the estimates around this association. When allowing a range of ± 1 phase for a given Aβ-phase correct classification was given in 96.91% of the cases. In doing so, we provide a novel method to convert SUVR-levels into PET-Aβ phase estimates that can be easily translated into neuropathological phases of Aβ-deposition. This method allows direct conclusions about the pathological distribution of amyloid plaques (Aβ-phases) in vivo. Accordingly, this method may be ideally suited to detect early preclinical AD-patients, to follow them with disease progression, and to provide a more precise prognosis for them based on the knowledge about the underlying pathological phase of the disease.

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Monitoring of patients with metastatic melanoma treated with immune checkpoint inhibitors using PET–CT

Abstract

Immune checkpoint inhibitors (ICI) have revolutionized therapy of metastatic melanoma. The first ICI was ipilimumab, a cytotoxic T lymphocyte-associated Ag 4 (CLTA-4) inhibitor with response rates of approximately 11% and disease control of 22%. The programmed cell death 1 (PD-1) inhibitors, such as pembrolizumab and nivolumab, led to longer progression-free survival and overall survival rates with fewer side effects. Molecular imaging techniques, such as positron emission tomography–computed tomography (PET–CT) with 2-deoxy-2-(¹⁸F)fluoro-d-glucose (¹⁸F-FDG) are in use for staging and therapy monitoring of metastatic melanoma. However, classical radiological imaging criteria such as RECIST and WHO are not appropriate for the assessment of ICI response. New immune-related criteria have been defined such as iRECIST or irRC, which refer to radiological imaging modalities. Until now only a few studies report on immunotherapy response assessment based on ¹⁸F-FDG PET–CT. The classical criteria used for therapy monitoring with ¹⁸F-FDG PET, such as the EORTC criteria, are not suitable for ICI monitoring. In this focussed review, we present different criteria proposed for ICI monitoring with ¹⁸F-FDG and their limitations. One goal is to early identify non-responders to tailor immunotherapy. Another question is pseudoprogression and how to interpret the ¹⁸F-FDG images for response assessment. Finally, the definition of ¹⁸F-FDG criteria which can be used to identify progress is crucial and discussed in the review. The recent presented PET-based immune-related criteria, the so-called PERCIMT (PET Response Evaluation Criteria for IMmunoTherapy) are presented. Furthermore, new tracers are discussed.

https://ift.tt/2L507Ga

Monitoring of patients with metastatic melanoma treated with immune checkpoint inhibitors using PET–CT

Abstract

Immune checkpoint inhibitors (ICI) have revolutionized therapy of metastatic melanoma. The first ICI was ipilimumab, a cytotoxic T lymphocyte-associated Ag 4 (CLTA-4) inhibitor with response rates of approximately 11% and disease control of 22%. The programmed cell death 1 (PD-1) inhibitors, such as pembrolizumab and nivolumab, led to longer progression-free survival and overall survival rates with fewer side effects. Molecular imaging techniques, such as positron emission tomography–computed tomography (PET–CT) with 2-deoxy-2-(¹⁸F)fluoro-d-glucose (¹⁸F-FDG) are in use for staging and therapy monitoring of metastatic melanoma. However, classical radiological imaging criteria such as RECIST and WHO are not appropriate for the assessment of ICI response. New immune-related criteria have been defined such as iRECIST or irRC, which refer to radiological imaging modalities. Until now only a few studies report on immunotherapy response assessment based on ¹⁸F-FDG PET–CT. The classical criteria used for therapy monitoring with ¹⁸F-FDG PET, such as the EORTC criteria, are not suitable for ICI monitoring. In this focussed review, we present different criteria proposed for ICI monitoring with ¹⁸F-FDG and their limitations. One goal is to early identify non-responders to tailor immunotherapy. Another question is pseudoprogression and how to interpret the ¹⁸F-FDG images for response assessment. Finally, the definition of ¹⁸F-FDG criteria which can be used to identify progress is crucial and discussed in the review. The recent presented PET-based immune-related criteria, the so-called PERCIMT (PET Response Evaluation Criteria for IMmunoTherapy) are presented. Furthermore, new tracers are discussed.

https://ift.tt/2L507Ga

Tribulus terrestris improves metronidazole-induced impaired fertility in the male mice

Introduction: Fruit extract of Tribulus terrestris (TT) bears aphrodisiac and antioxidative properties. Antimicrobial drug, metronidazole (MTZ) impairs the spermatogenic activity and fertility in males.
Objective: Validation of the use of fruit extract of TT as a supplement against MTZ-induced fertility impairment in males.

Methods: Adult Swiss strain male mice were administered with 500mg/kgBW/day of MTZ for 28 days. Low (100mg/kgBW/day) and high (200mg/kgBW/day) doses of TT were administered simultaneously with MTZ (500mg/kgBW/day) for same duration. All males were cohabited with virgin proestrus females. Vaginal plug formation was observed to calculate the libido index. Cohabited females were sacrificed on fifteenth day of gestation to dissect out the ovaries and uteri. Fertility index, quantal pregnancy, pre-implantation and post-implantation losses were calculated. 

Results: MTZ-treated males showed unaltered mating ability, however, the females impregnated by such males exhibited marked alterations in the fertility index, quantal pregnancy and pre- and post-implantation losses. Supplementation with low dose of TT failed to restore such reproductive toxicities exhibited by administration of MTZ. However, the altered reproductive toxicities were reinstated to control values following supplementation with high dose of TT.
Conclusion: The fruit extract of TT may emerge as an effective herbal remedy, correcting the drug-induced fertility impairments in males.

Keywords: Female mice, fertility, male mice, metronidazole, Tribulus terrestris.

 

 

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Cystic fibrosis in Tunisian children: a review of 32 children

Background: Cystic fibrosis is rare in Tunisia.Its diagnosis requires experienced specialists. Its prognosis is poor in developing countries.
Objectives: To study the epidemiologic, clinical, genetic features and the therapeutic challenges of cystic fibrosis in Tunisian children.
Methods: Covering a period of 21 years, this retrospective study included all patients with a definite diagnosis of cystic fibrosis from the Pediatrics Department B of The Children's Hospital of Tunis.
Results: Data from 32 children (14 boys and 18 girls) were collected. The diagnosis was made during the first year of life in 28 cases. Meconium ileus was found in 5 cases, respiratory manifestations in 22 cases, chronic diarrhea in 19 cases, faltering growth in 17 cases and a pseudo Barter syndrome in 2 cases. The sweat chloride test was positive in all cases. The most frequent mutation was F508del (56% of cases). Respiratory complications marked the outcome. Among our 32 patients, 15 patients (50%) died at an average age of 5 years and 3 months, mainly due to respiratory failure. The mean age of the surviving patients was 5 years.
Conclusion: Cystic fibrosis prognosis is poor in our series compared to developed countries due to the longer diagnostic delay and the limited therapeutic options.

Keywords: Cystic fibrosis, children, Tunisia.

https://ift.tt/2PlxwQ7

A study on visual, audio and tactile reaction time among medical students at Kampala International University in Uganda

Background: Reaction time (RT) is an indicator of neural activity, however, its variation due to visual (VRT), audio (ART) and tactile (TRT) in African medical students has not been investigated. The aim of the study was to determine relationships between VRT, ART and TRT amongst medical students in Uganda.
Materials and methods: This was a cross sectional study, the body mass index (BMI) and RT (i.e. VRT, ART and TRT) were determined using weighing scale with standiometer and the catch a ruler experiment respectively. A questionnaire was administered to collect information on participant's lifestyle patterns and analysis was done using SPSS Version 20.
Results: The mean (± SEM) VRT, ART and TRT in the study were found to be 0.148 ± 0.002s, 0.141 ± 0.002s and 0.139 ± 0.003s respectively. A strong correlation between TRT and ART was found to exist in the youthful Ugandan medical student's population. Furthermore, significant differences in ART and VRT were observed with sex, although these were absent amongst preclinical and clinical students, showing the importance of sex in RT.
Conclusion: The low VRT and ART in Ugandan medical students is indicative of a healthy somatosensory connectivity, thus of academic importance.

Keywords: Reaction time, cognitive performance, neural health, medical education.

https://ift.tt/2MYU1c3

A randomized control trial comparing train of four ratio > 0.9 to clinical assessment of return of neuromuscular function before endotracheal extubation on critical respiratory events in adult patients undergoing elective surgery at a tertiary hospital in

Background: There is increasing evidence that the incidence of postoperative residual paresis after using neuromuscular blockers ranges from 24 to 50% in post anaesthesia care unit (PACU) and is associated with postoperative complications such as critical respiratory events as evidenced by hypoxia, hypoventilation and upper airway obstruction. Quantitative neuromuscular monitoring (such as the assessment of Train of four (TOF) ratio) and reversal of neuromuscular blockers has been shown to reduce postoperative residual paresis. There are very few outcome studies on effect of residual paresis in PACU. There is a paucity of published randomized controlled trials investigating whether using a TOF ratio ≥0.9 before endotracheal extubation compared to clinical assessment of return of neuromuscular function reduces the incidence of critical respiratory events in PACU.
Objective: To determine whether using TOF ratio ≥ 0.9 compared to clinical assessment of return of neuromuscular function before endotracheal extubation reduces the incidence of critical respiratory events in PACU
Methods: Onehundred sixty eight adult patients in ASA physical status I and II requiring general anaesthesia for elective surgery with cisatracurium as the muscle relaxant were randomized into 2 groups of 84 each. Group 1 were patients who required a TOF ratio of ≥0.9 before extubation. Group 2 patients were extubated based on clinical assessment of return of adequate neuromuscular function by the anaesthetist as is the standard of practice at the Aga Khan University hospital Nairobi. General anaesthesia was standardized in both groups. Both the investigators and patients were blinded during the study. Once the patient was transferred to PACU, oxygen saturation (SP02), respiratory rate and any signs of upper airway obstruction as demonstrated by stridor, laryngospasms or requirement of any airway manipulation was recorded for the first 30 minutes. Duration of anaesthesia and surgery was also recorded. Patient demographics were recorded and analyzed.
Results: There was no statistical difference between the 2 groups in terms of patient demographics, duration of surgery and anaesthesia and duration since last muscle relaxant was given. In terms of hypoxia on arrival in PACU, the incidence of mild hypoxia (SPO2 90-93%) was 11% in clinical assessment groupversus 5% in TOF group P-value 0.149 while severe hypoxia (SPO2 <90%) was 19% versus 10% P-value 0.078. During the first 30 minutes in PACU, the incidence of mild hypoxia (SPO2 90-93%) was statistically significant between the 2 groups (12% in clinical assessment group versus 1% in TOF group, P-value 0.005) while severe hypoxia (SPO2 <90%) was 7% versus 5%, P-value 0.373. The incidence of upper airway obstruction was statistically significant between the two groups (45% in clinical assessment group versus 14% in TOF group P-value<0.0001 for patients requiring airway maneuver, 21% versus 2% P-value <0.0001 for those who required tactile stimulation and 31% versus 12% were snoring, P-value 0.003. Logistic regression analysis revealed TOF group was less likely associated with mild hypoxia (OR 0.09 95% CI 0.01-0.71 P-value 0.023), tactile stimulation (OR 0.09 95% CI 0.02-0.40 P-value 0.002), airway maneuver (OR 0.20 95% CI 0.10-0.43 P-value <0.001) and snoring (OR 0.30 95% CI 0.13-0.68 P-value 0.04).
Conclusion: Among this population, there is a lower incidence of critical respiratory events in PACU with the use of neuromuscular monitoring using TOF ratio ≥0.9 to assess neuromuscular function before endotracheal extubation compared with the use of clinical assessment methods.

Keywords: Randomized control trial, neuromuscular function, elective surgery, Nairobi.

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