Tysnd1 deficiency in mice interferes with the peroxisomal localization of PTS2 enzymes, causing lipid metabolic abnormalities and male infertility.

Peroxisomes are subcellular organelles involved in lipid metabolic processes, including those of very-long-chain fatty acids and branched-chain fatty acids, among others. Peroxisome matrix proteins are synthesized in the cytoplasm. Targeting signals (PTS or peroxisomal targeting signal) at the C-terminus (PTS1) or N-terminus (PTS2) of peroxisomal matrix proteins mediate their import into the organelle. In the case of PTS2-containing proteins, the PTS2 signal is cleaved from the protein when transported into peroxisomes. The functional mechanism of PTS2 processing, however, is poorly understood. Previously we identified Tysnd1 (Trypsin domain containing 1) and biochemically characterized it as a peroxisomal cysteine endopeptidase that directly processes PTS2-containing prethiolase Acaa1 and PTS1-containing Acox1, Hsd17b4, and ScpX. The latter three enzymes are crucial components of the very-long-chain fatty acids ß-oxidation pathway. To clarify the in vivo functions and physiological role of Tysnd1, we analyzed the phenotype of Tysnd1(-/-) mice. Male Tysnd1(-/-) mice are infertile, and the epididymal sperms lack the acrosomal cap. These phenotypic features are most likely the result of changes in the molecular species composition of choline and ethanolamine plasmalogens. Tysnd1(-/-) mice also developed liver dysfunctions when the phytanic acid precursor phytol was orally administered. Phyh and Agps are known PTS2-containing proteins, but were identified as novel Tysnd1 substrates. Loss of Tysnd1 interferes with the peroxisomal localization of Acaa1, Phyh, and Agps, which might cause the mild Zellweger syndrome spectrum-resembling phenotypes. Our data established that peroxisomal processing protease Tysnd1 is necessary to mediate the physiological functions of PTS2-containing substrates.

The Effectiveness of Online Course Intervention to Improve Knowledge of Antimicrobial Resistance among Dental Students, in Comparison to Reference Group Using a Randomized Controlled Trial.

AIM: This study aimed to assess the effectiveness of a recognised antimicrobial resistance (AMR) online module on knowledge and perception among dental students, using a randomised controlled trial study design. METHODS: Dental students (n = 64, aged 21-25 years) in clinical years agreed to participate in this triple-blinded, parallel, randomised controlled trial. There were 34 students in the study group and 30 students in the control group. The study group participated in an online course covering information about AMR, while students in the control group received another online course about microorganisms in dentistry. Both groups were assessed three times using online questionnaires: before the intervention (T1), after the intervention (T2), and two months later (T3). Each one of T1, T2 and T3 had 22 questions. The questions were repeated each time in T1, T2, and T3 asking about AMR but with different question format, to avoid the possibility of students to memorise the answers. RESULTS: The mean (m) of correct answers for all students on T1 was 12.56, with standard deviation (SD) of 3.2. On T2, m = 14.03 and SD = 3.85, and on T3, m = 14.36 and SD = 3.71. Scores ranged from 0 to 22. The participants in the study and control groups showed significant score improvements from T1 to T2, immediately after the intervention, but there was no significant difference between T2 and T3. The study group students' scores did not improve significantly from T1 to T3, in contrast to the control group students' scores. More importantly, there was no significant difference in improvement from T1 to T2 when comparing the study and control groups. CONCLUSION: Online courses might not be reliable learning methods for ensuring the optimal levels of AMR knowledge that are needed by dental practitioners.

The Safety, Cosmetic Outcome, and Patient Satisfaction after Inferior Pedicle Reduction Mammaplasty for Significant Macromastia.

BACKGROUND: Significant macromastia is socially and physically debilitating. Reduction mammaplasty in these cases carries significant morbidity. METHODS: Cases of inferior pedicle reduction mammaplasty performed at the breast unit, King Fahd Hospital, Jeddah, Saudi Arabia, over the last 10 years were reviewed. Inclusion criteria were cases with significant macromastia in which the distance from the supra-sternal notch to the nipple was ≥ 40 cm. RESULTS: There were 26 cases of inferior pedicle reduction mammaplasty done for significant macromastia. The average age was 34.56 years (range, 16-56 years). The average sternal notch to the nipple distance was 43.08 cm (range, 40-49 cm). The average amount of breast tissue removed from the right breast was 1,057.6 g (range, 495-2,450) and from the left breast was 959.4 g (range, 445-2,100). Postoperatively, 4/26 (15.4%) had ecchymosis, 9/26 (34.6%) developed T-junction sloughing, 2/26 (7.7%) had wound infection, and 1/26 (3.8%) had unilateral partial nipple-areola complex ischemia. In 7/26 (26.9%), scars were evident and revision was performed in 4/26 (15.4%) cases. Variable degrees of upper breast flattening and bottoming were seen in most cases; however, these variations were more profound in fatty breasts and longer pedicles. The average follow-up period was 26.04 months (range, 3-68 months). All patients were satisfied with the reduced breast heaviness, but only 19/26 (73.1%) were highly satisfied with the breast shape and scars. CONCLUSIONS: In cases of significant macromastia, inferior pedicle reduction mammaplasty is a safe procedure. Evident scars, upper breast flattening, and bottoming adversely affect the level of satisfaction.

Quantification of glutaric and 3-hydroxyglutaric acids in urine of glutaric acidemia type I patients by HPLC with intramolecular excimer-forming fluorescence derivatization.

BACKGROUND: Glutaric aciduria type I (GA1) is an autosomal recessive disorder that usually causes neurological damage. Early diagnosis of the disease prior to the appearance of clinical symptoms can lead to better outcomes. METHODS: We describe a simple and selective HPLC method with intramolecular excimer-forming fluorescence derivatization to diagnose GA1. Glutaric acid (GA) and 3-hydroxyglutaric acid (3HGA) in urine and an internal standard were derivatized with 1-pyrenebutyric hydrazide (PBH). The derivatives were separated on a C18 column and fluorometrically detected at 475 nm (excitation of 345 nm) with a run time of 18 min. RESULTS: Excellent linearity over a wide range, reproducibility (coefficient of variation < or =14.5%), and sensitivity (limit of detection 0.4 micromol/l 3HGA and 0.2 micromol/l GA) were obtained. A retrospective study on previously diagnosed GA1 patients' urine from our laboratory archives between 1999 and 2004 was performed by analysts blinded to the study. CONCLUSIONS: The method enabled us to differentiate GA1 cases (n=36) from controls (n=99), regardless of the years of urine storage. The method is valuable for both retrospective and prospective diagnoses of GA1.

Identification of a novel IVD mutation in a consanguineous family with isovaleric acidemia.

Isovaleric acidemia (IVA) is a rare autosomal recessive disorder caused by a deficiency of isovaleryl-CoA dehydrogenase encoded by IVD gene. In this case study we report the first Saudi IVA patients from a consanguineous family with a novel transversion (p.G362V) and briefly discuss likely phenotype-genotype correlation of the disease in the Saudi population. We explored the functional consequences of the mutation by using various bioinformatics prediction algorithms and discussed the likely mechanism of the disease caused by the mutation.

Analysis of organic acid markers relevant to inherited metabolic diseases by ultra-performance liquid chromatography/tandem mass spectrometry as benzofurazan derivatives.

We describe a new approach applicable to the determination of organic acids that serve as diagnostic markers for several inherited metabolic disorders. We utilized liquid chromatography/tandem mass spectrometry for analysis of organic acid derivatives of a recently described benzofurazan reagent. The derivatization step was necessary to obtain organic acid derivatives suitable for analysis by reversed-phase liquid chromatography with high ionization efficiency for mass spectrometry in the positive-ion mode. In this work, a group of related dicarboxylic acid markers containing five or six carbon atoms were analyzed and validation was performed for glutaric and 3-hydroxyglutaric acids, the specific markers for glutaric acidemia type 1. Derivatization was achieved by reacting untreated urine with the derivatization reagent under mild conditions. The reaction mixture was analyzed on a C18 ultra-performance liquid chromatography (UPLC) column (50x2.1 mm, 1.7 microm) and detected in the multiple reaction monitoring mode in 5 min. Calibration curves were linear up to at least 1000 microM with detection limits for glutaric and 3-hydroxyglutaric acids of 0.025 and 0.02 microM, respectively (signal-to-noise ratio of 3). Intra-day (n=11) and inter-day (n=6) coefficients of variation were better than 11.2%. The assay was successfully applied to control (n=134) and glutaric acidemia type 1 (n=55) urine samples.