Atlantooccipital assimilation associated with combined atlas arch defect: a radiological case report.

In this report, atlantooccipital assimilation (AS), anterior arch defect (AAD), and posterior arch defect (PAD) of the atlas, and several variations around the craniocervical junction were identified on computed tomography (CT) of a patient of unknown sex and age. Coronal and sagittal CT scans showed AS and bilateral fusion of the atlas and the base of occipital bone. Axial CT scan at the atlas revealed PAD type B on the left side and midline AAD. Morphometric measurements indicated a potential ventral spinal cord compression. In addition, mid-sagittal CT revealed the presence of fossa navicularis magna and incomplete formation of the transverse foramen on the right side. This study reports an extremely rare AS associated with AAD, PAD, and other variations of the clivus and the atlas. To our knowledge, no similar case has been reported in the literature.

Normative Reference Values of the Tibial Nerve in Healthy Individuals Using Ultrasonography: A Systematic Review and Meta-Analysis.

BACKGROUND: High-resolution ultrasound of the tibial nerve has been used for screening of several neurologic disorders, but normative reference values of tibial nerve cross-sectional areas (CSA) have not been well established. Thus, the present meta-analysis was performed to generate normative estimates of tibial nerve CSA at various sites of the lower limb based on ultrasonography. METHODS: Google Scholar, Scopus and PubMed were searched for potential studies. Studies were required to report tibial nerve CSA in healthy individuals to be included. A random-effect meta-analysis was performed to calculate tibial nerve CSA values. Subgroup and statistical analyses were performed to study covariates. RESULTS: Forty-eight eligible articles consisting of 2695 limbs were included. The average tibial nerve CSA was found to be 10.9 mm2 at the ankle (95% CI: 9.9-11.8) and should not exceed 11.8 mm2 in healthy adults. At the popliteal fossa, the overall CSA was 21.7 mm2 (95% CI: 17.5-25.8) in healthy adults. At both sites, the average tibial nerve CSA was significantly larger in adults than in children, and the differences by geographical region were not statistically significant. At the ankle, tibial nerve CSA increased with age and body mass index, while at the popliteal fossa it increased with age and weight. CONCLUSIONS: our findings indicate that the tibial nerve varied not only along its course but also among sub-variables. Establishing normal references values of tibial nerve CSA is helpful to differentiate healthy from diseased tibial nerves such as in diabetic peripheral neuropathy or tarsal tunnel syndrome.

Cross-Sectional Area of the Tibial Nerve in Diabetic Peripheral Neuropathy Patients: A Systematic Review and Meta-Analysis of Ultrasonography Studies.

Background: There is a link between diabetic peripheral neuropathy (DPN) progression and the increase in the cross-sectional area (CSA) of the tibial nerve at the ankle. Nevertheless, no prior meta-analysis has been conducted to evaluate its usefulness for the diagnosis of DPN. Methods: We searched Google Scholar, Scopus, and PubMed for potential studies. Studies had to report tibial nerve CSA at the ankle and diabetes status (DM, DPN, or healthy) to be included. A random-effect meta-analysis was applied to calculate pooled tibial nerve CSA and mean differences across the groups. Subgroup and correlational analyses were conducted to study the potential covariates. Results: The analysis of 3295 subjects revealed that tibial nerve CSA was 13.39 mm2 (CI: 10.94−15.85) in DM patients and 15.12 mm2 (CI: 11.76−18.48) in DPN patients. The CSA was 1.93 mm2 (CI: 0.92−2.95, I2 = 98.69%, p < 0.01) larger than DPN-free diabetic patients. The diagnostic criteria of DPN and age were also identified as potential moderators of tibial nerve CSA. Conclusions: Although tibial nerve CSA at the ankle was significantly larger in the DPN patients, its clinical usefulness is limited by the overlap between groups and the inconsistency in the criteria used to diagnose DPN.

Shrimp thrombospondin (TSP): presence of O-ß1,4 N-acetylglucosamine polymers and its function in TSP chain association in egg extracellular matrix.

We characterized the existence of O-ß(1,4)-GlcNAc polymers (ß1,4GNP) that were anchored on the O-linked glycosylation sites of shrimp thrombospondin (pmTSP-II). There were five putative ß1,4GNP linkages on the epithelial growth factor-like domain of pmTSP-II. Antibody against O-ß-GlcNAc (CTD110.6) was used to prove the existence of linear and complex ß1,4GNP. The antibody well reacted with linear chito-triose, -tetraose and -pentaose conjugated with phosphatidylethanolamine lipid. The immunoreactivity could also be detected with a complex ß1,4GNP within pmTSP-II (at MW > 250 kDa). Upon denaturing the protein with SDS-PAGE buffer, the size of pmTSP-II was shifted to be 250 kDa, approximately 2.5 folds larger than the deduced molecular mass of pmTSP-II (110 kDa), suggesting additional association of pmTSP-II apart from its known disulfide bridging. This was confirmed by chitinase digestion on pmTSP-II protein leading to the subsequent smaller protein bands at 110-170 kDa in time- and concentration-dependent manners. These bands well reacted with CTD110.6 antibody and disappeared after extensive chitinase hydrolysis. Together, we believe that ß1,4GNP on pmTSP-II serve the function in an inter-chain association to provide structural architecture of egg extracellular matrix, a novel function of pmTSP-II in reproductive biology.

The decreasing prevalence of the thyroid ima artery: A systematic review and machine learning assisted meta-analysis.

INTRODUCTION: Thyroid ima artery is a variant artery found on the anterior surface of the trachea. The aim of this meta-analysis was to obtain pooled prevalence data of the thyroid ima artery and discuss its clinical importance especially for tracheostomy. METHODS: A systematic literature search was performed through five electronic databases until May 2021. A set of inclusion and exclusion criteria based on AQUA guidelines were used to select relevant studies. Meta-analysis, subgroup analyses, meta-regression, and tests for publication bias were performed. Factors that influence the prevalence of the thyroid ima artery were detected using simple and interpretable machine learning (linear regression and K means). RESULTS: Thirty-six studies with a total of 4335 subjects met the inclusion criteria. The prevalence of the thyroid ima artery was 3.8% (95% CI: 0.027-0.049, I2=56.2%). Machine learning identified age, region and year of publication as potential covariates. Subgroup analysis showed that the prevalence of the thyroid ima artery was 4.5 times higher in fetuses (14.8%) than adults (3.3%) (z=-6.76, p<0.01). There was a significant negative correlation between the adult prevalence of the thyroid ima artery and the year of publication (Pearson's r=-0.354, p=0.040) thereby suggesting a decline in thyroid ima artery prevalence over time. This artery, if present, may originate from the brachiocephalic trunk (74%), right common carotid artery (9.6%), arch of aorta (7.7%), right internal thoracic artery (4.8%), left common carotid artery (1.9%) and left internal thoracic artery (1.9%). CONCLUSION: In addition to evidence-based synthesis of the thyroid ima artery, this study is the first ever study to report the decreasing prevalence over time of a human body structure in the postnatal life. Knowledge of the thyroid ima artery is of vital importance for surgeons to avoid accidental hemorrhage during tracheostomy.

N-linked mannose glycoconjugates on shrimp thrombospondin, pmTSP-II, and their involvement in the sperm acrosome reaction.

Glycoconjugates in egg extracellular matrices are known to serve several functions in reproductive processes. Here, the presence of N-linked mannose (Man) glycoconjugates on shrimp thrombospondin ( pmTSP-II) and their physiological functions were investigated in the black tiger shrimp Penaeus monodon. A molecular analysis of pmTSP-II demonstrated anchorage sites for N-linked glycans in both the chitin-binding and TSP3 domains. The presence of Man residues was verified by concanavalin A lectin histochemistry on the purified fraction of pmTSP-II (250 kDa with protease inhibitor). The function of the Man glycoconjugates was evident by the Con A interference with the pmTSP-II-induced acrosome reaction (AR) as well as by the ability to recover the induction of the AR by the inclusion of Mans in the treatment mixture. In addition, the recombinant proteins of the three signature pmTSP-II domains expressed in E. coli (lacking glycosylation) and mannosidase-treated pmTSP-II showed a minimal ability to initiate the AR response. Together, these results provide evidence of the pivotal role that Man-linked pmTSP-II plays in modulating the shrimp sperm AR, a novel role for a TSP family protein in shrimp reproductive biology.

Distribution of abalone egg-laying hormone-like peptide in the central nervous system and reproductive tract of the male mud crab, Scylla olivacea.

The mud crab, Scylla olivacea, is a high value economic marine animal in Thailand. However, collection of these crabs from natural habitat for local consumption and export has caused rapid population decline. Hence, aquaculture of this species is required and to this measure understanding of endocrine control of their reproduction must be understood. Egg laying hormone (ELH) is a neuropeptide synthesized by the bag cells (neurons) in the abdominal ganglia of Aplysia gastropods. It plays a critical role in controlling egg production and laying in gastropods, and its possible homolog (ELH-like peptide) was reported in the neural and ovarian tissues of prawns and recently in female reproductive tract of the blue swimming crab, Portunus pelagicus. In this study, we have studied the histology of the male reproductive tract in Scylla olivacea which are comprised of anterior testis, posterior testis, early proximal spermatic duct (ePSD), proximal spermatic duct (PSD), middle spermatic duct (MSD) and distal spermatic duct (DSD), by immunohistochemistry, detected an abalone ELH- immunoreactivity (aELH-ir) in epithelium of ducts in posterior testis and epithelium of all parts of spermatic duct. Furthermore, we could detect aELH-ir in neurons of cluster 9, 11, olfactory neuropil (ON) in the brain and in the small neurons located between the third and the fourth thoracic neuropils (T3-T4) and between the fourth and the fifth thoracic neuropils (T4-T5) of thoracic ganglia. Thus, the presence of aELH in male S. olivacea was designated the role of female egg laying behavior in the male mud crab.

Three-dimensional organization of the brain and distribution of serotonin in the brain and ovary, and its effects on ovarian steroidogenesis in the giant freshwater prawn, Macrobrachium rosenbergii.

The giant freshwater prawn, Macrobrachium rosenbergii, is an economically important crustacean species which has also been extensively used as a model in neuroscience research. The crustacean central nervous system is a highly complex structure, especially the brain. However, little information is available on the brain structure, especially the three-dimensional organization. In this study, we demonstrated the three-dimensional structure and histology of the brain of M. rosenbergii together with the distribution of serotonin (5-HT) in the brain and ovary as well as its effects on ovarian steroidogenesis. The brain of M. rosenbergii consists of three parts: protocerebrum, deutocerebrum and tritocerebrum. Histologically, protocerebrum comprises of neuronal clusters 6-8 and prominent anterior and posterior medial protocerebral neuropils (AMPN/PMPN). The protocerebrum is connected posteriorly to the deutocerebrum which consists of neuronal clusters 9-13, medial antenna I neuropil, a paired lateral antenna I neuropils and olfactory neuropils (ON). Tritocerebrum comprises of neuronal clusters 14-17 with prominent pairs of antenna II (AnN), tegumentary and columnar neuropils (CN). All neuronal clusters are paired structures except numbers 7, 13 and 17 which are single clusters located at the median zone. These neuronal clusters and neuropils are clearly shown in three-dimensional structure of the brain. 5-HT immunoreactivity (-ir) was mostly detected in the medium-sized neurons and neuronal fibers of clusters 6/7, 8, 9, 10 and 14/15 and in many neuropils of the brain including anterior/posterior medial protocerebral neuropils (AMPN/PMPN), protocerebral tract, protocerebral bridge, central body, olfactory neuropil (ON), antennal II neuropil (Ann) and columnar neuropil (CN). In the ovary, the 5-HT-ir was light in the oocyte step 1(Oc1) and very intense in Oc2-Oc4. Using an in vitro assay of an explant of mature ovary, it was shown that 5-HT was able to enhance ovarian estradiol-17ß (E2) and progesterone (P4) secretions. We suggest that 5-HT is specifically localized in specific brain areas and ovary of this prawn and it plays a pivotal role in ovarian maturation via the induction of female sex steroid secretions, in turn these steroids may enhance vitellogenesis resulting in oocyte growth and maturation.

Alpha-2 macroglobulin as a region-specific secretory protein in male reproductive tract, and its dynamics during sperm transit toward the female spermatheca in the blue crab.

A 250-kDa protein was isolated from fluid in the middle spermatic duct (MSD) of the blue crab (Portunus pelagicus). N-terminal and partial amino acid sequences revealed that this MSD-specific protein is highly similar to the plasma-enriched protein Alpha-2 macroglobulin (α2M). The P. pelagicus ortholog (Ppα2M) is a large glycoprotein possessing mannose and N-acetylglucosamine residues. Ppa2m mRNA was detected in the spermatic duct, androgenic gland, and hematopoietic tissue, whereas the protein was primarily observed in the apical cytoplasm of MSD epithelium and in the matrix of the acrosome of MSD sperm; distally within spermatic duct, Ppα2M was lost from the sperm membrane but remained in the sperm acrosome. These results suggest that Ppα2M is expressed and glycosylated in the epithelium of spermatic ducts, secreted into MSD fluid, taken up by sperm in the MSD, and removed from the surface of sperm during its transit towards the female spermatheca. Given that Ppα2M also exhibits protease inhibitor activity, we hypothesize that acrosome localized Ppα2M may suppress premature acrosome reaction during post-testicular sperm maturation in this crab.

Presence of gonadotropin-releasing hormone-like peptide in the central nervous system and reproductive organs of the male blue swimming crab, Portunus pelagicus, and its effect on spermatogenesis.

Our previous studies have demonstrated that lamprey gonadotropin-releasing hormone-III (lGnRH-III)-like peptide occurs in the central nervous system (CNS) of decapod crustaceans (Macrobrachium rosenbergii, Penaeus monodon, Portunus pelagicus), and that lGnRH-III is the most potent in stimulating ovarian maturation compared with other GnRH isoforms. In this study, we examined the localization of lGnRH-III-like peptide in the CNS and male reproductive organs of the blue swimming crab by using anti-lGnRH-III as a probe. In the brain, lGnRH-III immunoreactivity (-ir) was detected in neurons of clusters 6, 10, 11, 14/15, 16, and 17 and in many neuropils. In the subesophageal ganglion, lGnRH-III-ir was present in neurons of the dorso-lateral and ventro-medial clusters. In the thoracic ganglia, lGnRH-III-ir was observed in the large-sized neurons between the thoracic neuropils and in the ventromedial cluster of the abdominal ganglia. In the testis, lGnRH-III-ir was detected in nurse cells, hemocytes, spermatids 2, and the outer and inner zones of the acrosomes of spermatozoa. Bioassay showed that lGnRH-III significantly increased the testis-somatic index, the percentage of late stages of seminiferous tubules (stages VII-IX), the diameter of the seminiferous tubules, and the number of BrdU-labeled early germ cells compared with the control groups. Thus, lGnRH-III-like peptide exists in the male crab and possibly enhances germ cell proliferation and maturation in the testes, leading to increased sperm production.

Histological organization of the central nervous system and distribution of a gonadotropin-releasing hormone-like peptide in the blue crab, Portunus pelagicus.

We present a detailed histological description of the central nervous system (CNS: brain, subesophageal ganglion, thoracic ganglia, abdominal ganglia) of the blue crab, Portunus pelagicus. Because the presence of gonadotropin-releasing hormone (GnRH) in crustaceans has been disputed, we examine the presence and localization of a GnRH-like peptide in the CNS of the blue crab by using antibodies against lamprey GnRH (lGnRH)-III, octopus GnRH (octGnRH) and tunicate GnRH (tGnRH)-I. These antibodies showed no cross-reactivity with red-pigment-concentrating hormone, adipokinetic hormone, or corazonin. In the brain, strong lGnRH-III immunoreactivity (-ir) was detected in small (7-17 µm diameter) neurons of clusters 8, 9 and 10, in medium-sized (21-36 µm diameter) neurons of clusters 6, 7 and 11 and in the anterior and posterior median protocerebral neuropils, olfactory neuropil, median and lateral antenna I neuropils, tegumentary neuropil and antenna II neuropil. In the subesophageal ganglion, lGnRH-III-ir was detected in medium-sized neurons and in the subesophageal neuropil. In the thoracic and abdominal ganglia, lGnRH-III-ir was detected in medium-sized and small neurons and in the neuropils. OctGnRH-ir was observed in neurons of the same clusters with moderate staining, particularly in the deutocerebrum, whereas tGnRH-I-ir was only detected in medium-sized neurons of cluster 11 in the brain. Thus, anti-lGnRH-III shows greater immunoreactivity in the crab CNS than anti-octGnRH and anti-tGnRH-I. Moreover, our functional bioassay demonstrates that only lGnRH-III has significant stimulatory effects on ovarian growth and maturation. We therefore conclude that, although the true identity of the crab GnRH eludes us, crabs possess a putative GnRH hormone similar to lGnRH-III. The identification and characterization of this molecule is part of our ongoing research.

Expression of the male reproduction-related gene in spermatic ducts of the blue swimming crab, Portunus pelagicus, and transfer of modified protein to the sperm acrosome.

Expression of a sex-specific gene in Macrobrachium rosenbergii (Mr-Mrr), encoding a male reproduction-related (Mrr) protein, has been identified in the spermatic ducts (SDs) and postulated to be involved in sperm maturation processes. M. rosenbergii is the only decapod that the expression and fate of the Mrr protein has been studied. To determine that this protein was conserved in decapods, we firstly used cloning techniques to identify the Mrr gene in two crabs, Portunus pelagicus (Pp-Mrr) and Scylla serrata (Ss-Mrr). We then investigated expression of Pp-Mrr by in situ hybridization, and immunolocalization, as well as phosphorylation and glycosylation modifications, and the fate of the protein in the male reproductive tract. Pp-Mrr was shown to have 632 nucleotides, and a deduced protein of 110 amino acids, with an unmodified molecular weight of 11.79 kDa and a mature protein with molecular weight of 9.16 kDa. In situ hybridization showed that Pp-Mrr is expressed in the epithelium of the proximal, middle, distal SDs, and ejaculatory ducts. In Western blotting, proteins of 10.9 and 17.2 kDa from SDs were all positive using anti-Mrr, antiphosphoserine/threonine, and antiphosphotyrosine. PAS staining showed they were also glycosylated. Immunolocalization studies showed Pp-Mrr in the SD epithelium, lumen, and on the acrosomes of spermatozoa. Immunofluorescence staining indicated the acrosome of spermatozoa contained the Mrr protein, which is phosphorylated with serine/threonine and tyrosine, and also glycosylated. The Mrr is likely to be involved in acrosomal activation during fertilization of eggs.