Organ-on-a-chip model of vascularized human bone marrow niches.

Bone marrow niches (endosteal and perivascular) play important roles in both normal bone marrow function and pathological processes such as cancer cell dormancy. Unraveling the mechanisms underlying these events in humans has been severely limited by models that cannot dissect dynamic events at the niche level. Utilizing microfluidic and stem cell technologies, we present a 3D in vitro model of human bone marrow that contains both the perivascular and endosteal niches, complete with dynamic, perfusable vascular networks. We demonstrate that our model can replicate in vivo bone marrow function, including maintenance and differentiation of CD34+ hematopoietic stem/progenitor cells, egress of neutrophils (CD66b+), and niche-specific responses to doxorubicin and granulocyte-colony stimulating factor. Our platform provides opportunities to accelerate current understanding of human bone marrow function and drug response with high spatial and temporal resolution.

Use of terlipressin in critically ill children with liver disease.

BACKGROUND: Terlipressin, a long-acting synthetic analogue of vasopressin has been used in the adult population for various indications including hepatorenal syndrome (HRS-AKI), esophageal variceal hemorrhage (EVH) and shock, but its use in pediatrics is still limited to individualized cases and data on safety and efficacy is scant. METHODS: We reviewed the patient records of children with liver disease and Acute Kidney Injury requiring terlipressin admitted to the Paediatric Intensive Care Unit (PICU) of King's College Hospital, London from January 2010-December 2017, with special emphasis on its effect on renal parameters and adverse event profile. RESULTS: Twenty-one terlipressin administration records in a total of 16 patients (median) (IQR) 10 years (6.1-14.4) were included. The drug was initially given as a bolus dose in all cases, followed by either bolus or infusion with median dosage being 5.2 (3.8-6.7) mcg/kg/hour. After administration, a sustained increase of mean arterial pressure was observed. There was an improvement in serum creatinine (Cr) (at 24 h; p = 0.386) and increase in urine output (UO), especially in the hepatorenal syndrome subgroup (HRS-AKI). We found minimal evidence of gastrointestinal side effects including feeding intolerance and vasoconstrictive side effects including cyanosis / ischaemia of extremities. CONCLUSION: Terlipressin was found to be safe in critically sick children with liver disease with positive impact on renal parameters which might be taken as a surrogate marker of HRS reversal, though effects on outcomes are difficult to ascertain. It is important to be aware of all its side-effects and actively watch for them. Future prospective studies are warranted to validate these findings.

Persistent Hiccups-An Unusual Presentation of Bilateral Pheochromocytoma without Syndromic Association: A Case Report.

Pheochromocytoma is a rare catecholamine-producing tumor arising from chromaffin tissue in the adrenal medulla, occurring in less than 0.2 percent of patients with hypertension. The mean age at diagnosis is about 40 years. Pheochromocytomas are commonly inherited as features of multiple endocrine neoplasia type 2 or several other pheochromocytoma-associated syndromes and have variable clinical presentation. Among the presenting symptoms, episodes of palpitations, headaches, and profuse sweating are typical and constitute a classic triad. We report a case of a 17-year-old male patient with rare bilateral pheochromocytoma presenting with persistent hiccups for 4 months and blurring of vision for 1 week, later followed by hypertensive crisis. There was neither family history of pheochromocytoma nor any classic symptoms. Patient was diagnosed with bilateral pheochromocytoma without any syndromic association. But still this patient needs to be followed for future development of medullary carcinoma of thyroid because it could be an initial presentation of MEN 2A/2B/VHL syndromes. Our paper highlights the importance of maintaining a high level of suspicion for persistent hiccups and careful clinical screening for hypertension even in absence of associated syndromes of pheochromocytoma and classical symptoms to achieve prompt diagnosis and to avoid improper management.