BF170 hydrochloride enhances the emergence of hematopoietic stem and progenitor cells.

Generation of hematopoietic stem and progenitor cells (HSPCs) ex vivo and in vivo, especially the generation of safe therapeutic HSPCs, still remains inefficient. In this study, we have identified compound BF170 hydrochloride as a previously unreported pro-hematopoiesis molecule, using the differentiation assays of primary zebrafish blastomere cell culture and mouse embryoid bodies (EBs), and we demonstrate that BF170 hydrochloride promoted definitive hematopoiesis in vivo. During zebrafish definitive hematopoiesis, BF170 hydrochloride increases blood flow, expands hemogenic endothelium (HE) cells and promotes HSPC emergence. Mechanistically, the primary cilia-Ca2+-Notch/NO signaling pathway, which is downstream of the blood flow, mediated the effects of BF170 hydrochloride on HSPC induction in vivo. Our findings, for the first time, reveal that BF170 hydrochloride is a compound that enhances HSPC induction and may be applied to the ex vivo expansion of HSPCs.

Anesthetic management of thyroid carcinoma invading the upper tracheal segment: A case report.

INTRODUCTION AND IMPORTANCE: Intratracheal tumors account for approximately 0.2 % of respiratory tumors, including primary and secondary tumors. Secondary tumors of the upper trachea are most commonly derived from advanced thyroid cancer. Surgical resection is currently the general curative modality for thyroid cancer with tracheal invasion. Patients with tracheal tumors invading and protruding into the lumen may have reduced oxygen reserve capacity, leading to a shorter safe window for general anesthesia induction. Establishing an appropriate artificial airway is essential to ensure intraoperative safety for these patients. Here, we report a case of tracheal tumor caused by differentiated papillary thyroid carcinoma invading the upper segment of the trachea and the non-conventional approach used for intraoperative airway management without traditional endotracheal intubation. PRESENTATION OF CASE: A 59-year-old female presented with bilateral neck masses and hemoptysis. The CT scan revealed suspicious malignant thyroid nodules, and tracheoscopy showed an approximately 50 % obstruction of the tracheal lumen. The patient's physical examination and biochemical examination showed no significant abnormalities. Based on imaging studies and pre-anesthetic assessment, a multidisciplinary team decided against performing endotracheal intubation in the patient due to the risk of tumor bleeding during the procedure. Instead, they opted for a modified endotracheal tube and the insertion of a laryngeal mask airway (LMA). The anesthesia induction and maintenance proceeded smoothly, with stable intraoperative hemodynamics. The tumor was successfully resected and tracheal anastomosis was performed without any complications. CLINICAL DISCUSSION: The strategy adroitly evades the risk of bleeding and dislodgement due to tumor contact during the intubation process. In this case report, the anesthetic highlight is the employment of a reverse insertion technique for endotracheal intubation, facilitated by a sterile suction catheter and complemented by an innovative modification to the tracheal tube. CONCLUSION: For patients with thyroid cancer invading the upper segment of the trachea, and in whom rapid induction anesthesia is anticipated not to cause tumor collapse, the use of laryngeal mask airway combined with modified tracheal tube mechanical ventilation is both safe and feasible.

Placement of bronchial occluder outside the tracheal tube in a patient combined with airway compression undergoing mediastinal tumors resection: a case report.

BACKGROUND: Mediastinal tumors pose a challenging respiratory and circulatory management during anesthesia procedures, there is a risk of circulatory collapse or complete airway obstruction, which in severe cases can lead to cardiac arrest. We reported a case of anesthetic management using a bronchial blocker placed outside the tracheal tube. In this case report, the patient's trachea was so severely compressed that the airway was extremely narrow, only 4 mm at its narrowest point. By reporting the anesthetic management of this patient, we intend to provide an unusual approach for airway management. CASE PRESENTATION: A 52-year-old male patient was admitted to the hospital due to cough and expectoration for one year. Additionally, the patient experienced chest tightness and asthma after physical activity. The enhanced computed tomography revealed there existed an irregular soft tissue mass in the right upper mediastinum, which significantly compressed the trachea and esophagus. The results of the mediastinal puncture pathology showed the presence of mesenchymal tumors. According to the results above, the patient was diagnosed with a mediastinal tumor and scheduled to undergo tumor resection under general anesthesia. We used a bronchial occluder outside the tracheal tube for general anesthesia. After surgery, the patient received thorough treatment and was subsequently discharged from the hospital. CONCLUSION: In patients with severe airway compression from a mediastinal tumor airway compression, positioning a bronchial occluder externally to the tracheal tube is an effective method of airway management. However, we still need more clinical practice to help the process become more standardized.

Reduction in SGLT1 mRNA Expression in the Ventromedial Hypothalamus Improves the Counterregulatory Responses to Hypoglycemia in Recurrently Hypoglycemic and Diabetic Rats.

The objective of this study was to determine whether the sodium-glucose transporter SGLT1 in the ventromedial hypothalamus (VMH) plays a role in glucose sensing and in regulating the counterregulatory response to hypoglycemia, and if so, whether knockdown of in the VMH can improve counterregulatory responses to hypoglycemia in diabetic rats or rats exposed to recurrent bouts of hypoglycemia (RH). Normal Sprague-Dawley rats as well as RH or streptozotocin (STZ)-diabetic rats received bilateral VMH microinjections of an adenoassociated viral vector containing either the SGLT1 short hairpin RNA (shRNA) or a scrambled RNA sequence. Subsequently, these rats underwent a hypoglycemic clamp to assess hormone responses. In a subgroup of rats, glucose kinetics was determined using tritiated glucose. The shRNA reduced VMH SGLT1 expression by 53% in nondiabetic rats, and this augmented glucagon and epinephrine responses and hepatic glucose production during hypoglycemia. Similarly, SGLT1 knockdown improved the glucagon and epinephrine responses in RH rats and restored the impaired epinephrine response to hypoglycemia in STZ-diabetic animals. These findings suggest that SGLT1 in the VMH plays a significant role in the detection and activation of counterregulatory responses to hypoglycemia. Inhibition of SGLT1 may offer a potential therapeutic target to diminish the risk of hypoglycemia in diabetes.

Key role for AMP-activated protein kinase in the ventromedial hypothalamus in regulating counterregulatory hormone responses to acute hypoglycemia.

OBJECTIVE: To examine in vivo in a rodent model the potential role of AMP-activated protein kinase (AMPK) within the ventromedial hypothalamus (VMH) in glucose sensing during hypoglycemia. RESEARCH DESIGN AND METHODS: Using gene silencing technology to selectively downregulate AMPK in the VMH, a key hypothalamic glucose-sensing region, we demonstrate a key role for AMPK in the detection of hypoglycemia. In vivo hyperinsulinemic-hypoglycemic (50 mg dl(-1)) clamp studies were performed in awake, chronically catheterized Sprague-Dawley rats that had been microinjected bilaterally to the VMH with an adeno-associated viral (AAV) vector expressing a short hairpin RNA for AMPKalpha. RESULTS: In comparison with control studies, VMH AMPK downregulation resulted in suppressed glucagon ( approximately 60%) and epinephrine (approximately 40%) responses to acute hypoglycemia. Rats with VMH AMPK downregulation also required more exogenous glucose to maintain the hypoglycemia plateau and showed significant reductions in endogenous glucose production and whole-body glucose uptake. CONCLUSIONS: We conclude that AMPK in the VMH plays a key role in the detection of acute hypoglycemia and initiation of the glucose counterregulatory response.

Blockade of GABA(A) receptors in the ventromedial hypothalamus further stimulates glucagon and sympathoadrenal but not the hypothalamo-pituitary-adrenal response to hypoglycemia.

Hypoglycemia provokes a multifaceted counterregulatory response involving the sympathoadrenal system, stimulation of glucagon secretion, and the hypothalamo-pituitary-adrenal axis that is commonly impaired in diabetes. We examined whether modulation of inhibitory input from gamma-aminobutyric acid (GABA) in the ventromedial hypothalamus (VMH), a major glucose-sensing region within the brain, plays a role in affecting counterregulatory responses to hypoglycemia. Normal Sprague-Dawley rats had carotid artery and jugular vein catheters chronically implanted, as well as bilateral steel microinjection guide cannulas inserted down to the level of the VMH. Seven to 10 days following surgery, the rats were microinjected with artificial extracellular fluid, the GABA(A) receptor agonist muscimol (1 nmol/side), or the GABA(A) receptor antagonist bicuculline methiodide (12.5 pmol/side) before being subjected to a hyperinsulinemic-hypoglycemic (2.5 mmol/l) glucose clamp for 90 min. Following VMH administration of bicuculline methiodide, glucose infusion rates were significantly suppressed, whereas muscimol raised glucose infusion rates significantly compared with controls. Glucagon and epinephrine responses were elevated with the antagonist and suppressed with the agonist compared with controls. Corticosterone responses, however, were unaffected by either administration of the agonist or antagonist into the VMH. These data demonstrate that modulation of the GABAergic system in the VMH alters both glucagon and sympathoadrenal, but not corticosterone, responses to hypoglycemia. Our findings are consistent with the hypothesis that GABAergic inhibitory tone within the VMH can modulate glucose counterregulatory responses.

Potential role for AMP-activated protein kinase in hypoglycemia sensing in the ventromedial hypothalamus.

The mechanisms by which specialized glucose-sensing neurons within the hypothalamus are able to detect a falling blood glucose remain largely unknown but may be linked to some gauge of neuronal energy status. We sought to test the hypothesis that AMP-activated protein kinase (AMPK), an intracellular kinase purported to act as a fuel sensor, plays a role in hypoglycemia sensing in the ventromedial hypothalamus (VMH) of the Sprague-Dawley rat by chemically activating AMPK in vivo through bilateral microinjection, before performing hyperinsulinemic-hypoglycemic or hyperinsulinemic-euglycemic clamp studies. In a subgroup of rats, H3-glucose was infused to determine glucose kinetics. The additional chemical activation by AICAR of AMPK in the VMH during hypoglycemia markedly reduced the amount of exogenous glucose required to maintain plasma glucose during hypoglycemia, an effect that was almost completely accounted for by a three- to fourfold increase in hepatic glucose production in comparison to controls. In contrast, no differences were seen between groups in hypoglycemia-induced rises in the principal counterregulatory hormones. In conclusion, activation of AMPK within the VMH may play an important role in hypoglycemia sensing. The combination of hypoglycemia- and AICAR-induced AMPK activity appears to result in a marked stimulus to hepatic glucose counterregulation.

Identification of critical amino acid residues on human dihydrofolate reductase protein that mediate RNA recognition.

Previous studies have shown that human dihydrofolate reductase (DHFR) acts as an RNA-binding protein, in which it binds to its own mRNA and, in so doing, results in translational repression. In this study, we used RNA gel mobility shift and nitrocellulose filter-binding assays to further investigate the specificity of the interaction between human DHFR protein and human DHFR mRNA. Site-directed mutagenesis was used to identify the critical amino acid residues on DHFR protein required for RNA recognition. Human His-Tag DHFR protein specifically binds to human DHFR mRNA, while unrelated proteins including thymidylate synthase, p53 and glutathione-S-transferase were unable to form a ribonucleoprotein complex with DHFR mRNA. The Cys6 residue is essential for RNA recognition, as mutation at this amino acid with either an alanine (C6A) or serine (C6S) residue almost completely abrogated RNA-binding activity. Neither one of the cysteine mutant proteins was able to repress the in vitro translation of human DHFR mRNA. Mutations at amino acids Ile7, Arg28 and Phe34, significantly reduced RNA-binding activity. An RNA footprinting analysis identified three different RNA sequences, bound to DHFR protein, ranging in size from 16 to 45 nt, while a UV cross-linking analysis isolated an approximately 16 nt RNA sequence bound to DHFR. These studies begin to identify the critical amino acid residues on human DHFR that mediate RNA binding either through forming direct contact points with RNA or through maintaining the protein in an optimal structure that allows for the critical RNA-binding domain to be accessible.