Unravelling the effect of blood group on FVIII:C levels and response to DDAVP in 20 males with a single genotype (Twillingate Variant) causing Haemophilia A.

INTRODUCTION: The genetic variant responsible for haemophilia A (HA) significantly impacts endogenous coagulant factor VIII (FVIII:C) level, thus impacting DDAVP responsiveness. Blood group (BG) also impacts FVIII:C levels, but this is difficult to evaluate in a genetically heterogeneous population. Canada has a large cohort of mild-moderate HA due to a single point variant: c.6104T>C, p.Val2035Ala-the Twillingate variant. AIM: To evaluate the impact of BG on endogenous FVIII:C levels and DDAVP responsiveness in a single genotype of mild-moderate HA. METHODS: This was a retrospective, single-centre study. BG and FVIII:C levels were obtained for males with the Twillingate variant. One-hour absolute and fold increases in FVIII:C post-DDAVP were calculated. T-tests and Mann-Whitney U tests were used to compare FVIII:C levels and DDAVP challenge variables between individuals according to BGs (O vs. non-O). RESULTS: Twenty males were included. There were significant differences between BGs (O vs. non-O) in their lowest FVIII:C level at age <12 years (medians: 0.05 vs. 0.08 IU/mL; P = .05). Fifteen subjects underwent DDAVP challenges. Mean 1-h FVIII:C were 0.29 (O BG) versus 0.41 IU/mL (non-O BG); P = .04. There were no significant differences between BGs (O vs. non-O) in mean absolute FVIII:C increase (0.20 vs. 0.27 IU/mL; P = .10) and FVIII:C fold increase (3.3-fold vs. 3.8-fold; P = .51). CONCLUSION: In HA subjects with an identical genotype, BG significantly impacts baseline FVIII:C levels and FVIII:C levels post-DDAVP, but does not impact absolute and fold increases in FVIII:C with DDAVP.

A multicenter study of DDAVP versus platelet transfusions for antiplatelet agent reversal in patients with traumatic brain injury.

BACKGROUND: Antiplatelet agents have been shown to worsen outcomes following traumatic injury. Research on desmopressin (DDAVP) and platelet transfusion for antiplatelet reversal is limited. We aimed to evaluate the effect of these agents on patients taking pre-injury antiplatelet medications who experienced traumatic brain injury (TBI) after blunt trauma. METHODS: This is a retrospective cohort study of adult trauma patients from 2014 to 2021 on aspirin and/or a P2Y12 inhibitor. Patients were stratified into groups based on if they received DDAVP, platelets, both agents, or neither. RESULTS: Of 5525 included patients, 4696 (85.4%) were not reversed, 461 (8.4%) received platelets, 173 (3.1%) received DDAVP, and 172 (3.1%) received both reversals. There was no statistically significant difference in length of stay between, but patients who received platelets or both reversals were more likely to have hospital complications (p < 0.05), longer hospital length of stay (p < 0.001), and longer ICU length of stay (p < 0.001) compared to those who did not receive reversal. A subgroup analysis of patients with a head AIS of 4 or 5 confirmed these findings. CONCLUSIONS: Patients who received platelets or both reversals had a longer length of hospital stay and length of ICU stay. It is difficult to recommend one treatment over another based on our results alone. Further studies are needed to help clarify the risks and benefits of reversal agents in this patient population.

[Successful immunosuppressive therapy in female hemophilia A developing inhibitor after perioperative administration of factor VIII products].

A 62-year-old woman was diagnosed as a hemophilia A carrier (factor VIII activity 35%) on preoperative examination of an ovarian tumor. A total of 35,600 units of recombinant factor VIII products was administered perioperatively. On postoperative day 95, a subcutaneous hematoma formed and immunosuppressive therapy with prednisolone was started based on an APTT of 66 seconds, factor VIII (FVIII) activity of 3%, and FVIII inhibitor of 1 BU/ml. During this treatment, the patient was hospitalized due to ankle joint bleeds and required hemostatic treatment, but the inhibitor disappeared and FVIII activity recovered to 30% after postoperative day 438 with cyclophosphamide. F8 analysis revealed the patient carried a heterozygosity of p.Arg391Cys, which has previously been categorized as cross-reacting material (CRM)-positive severe hemophilia A. No high-risk mutations for inhibitor development were found. We also report the results of a desmopressin acetate hydrate test administered to the patient to prepare for future treatment in case of hemorrhage, since high-dose FVIII administration may have been a factor in inhibitor development.

Desmopressin therapy in children and adults: pharmacological considerations and clinical implications.

PURPOSE: This review aims to provide prescribing clinicians a deeper appreciation of desmopressin's clinical indications and formulation types, to better balance efficacy and safety through proper formulation selection. BACKGROUND: Since its discovery 50 years ago, desmopressin's antidiuretic properties have been used for central diabetes insipidus, primary monosymptomatic nocturnal enuresis and adult nocturnal polyuria, while its coagulant effects are useful for mild hemophilia A and von Willebrand Disease. During this time, newer formulations of desmopressin have also been introduced to the market raising questions on interchangeability, dose conversion and safety. The wide array of clinical indications and variable pharmacokinetic properties of different desmopressin preparations raises the possibility of medication error, especially the risk of hyponatraemia. METHODOLOGY: A narrative review to explore clinically relevant aspects of desmopressin therapy, synthesising information obtained from searches of published literature. RESULTS: We identified that the risk factors for developing hyponatremia include extremes of age, existing comorbidity, drug interaction, intranasal formulations and intercurrent illness. We describe the dose equivalence between all formulations to facilitate conversion. We highlight that in view of inter-subject variability, close monitoring is recommended when switching preparations. We found that paediatric data remains limited, leading to recent proposals for age- and weight-based dosing regimens. CONCLUSION: The risk of hyponatremia, albeit small, can be reduced by adhering to the indication-specific doses and taking steps to govern the safe prescription of the drug. Further paediatric clinical trials are awaited to expand the evidence base of childhood desmopressin therapy.

The Safety and Efficacy of Desmopressin in Patients With Intracranial Hemorrhage and a History of Alcohol Use.

BACKGROUND: Patients with a history of alcohol use disorder are at an increased risk of hematoma expansion following intracranial hemorrhage (ICH) due to the effects of alcohol on platelet aggregation. Desmopressin (DDAVP) improves platelet aggregation and may decrease hematoma expansion in patients with ICH. However, DDAVP may also increase the risk of hyponatremia and thrombotic events. Evidence is limited regarding the safety and efficacy of DDAVP in alcohol use (AU)-associated ICH. METHODS: This was a retrospective chart review of adult patients with radiographic evidence of ICH and a confirmed or suspected history of alcohol use upon admission. Patients were categorized into groups based on DDAVP administration. Safety outcomes included hyponatremia (serum sodium <135 mEq/L or decrease in serum sodium of ≥ 5 mEq/L for patients with baseline sodium <135 mEq/L) within 24 hours of ICH and thrombotic events within 7 days of ICH. The primary efficacy outcome was the incidence of hematoma expansion, defined as any expansion of the hemorrhage noted on repeat imaging within 32 hours. RESULTS: In total, 52 patients were included in the safety analysis (27 DDAVP and 25 non-DDAVP). Although hyponatremia was numerically higher in the DDAVP group, there was no significant difference between groups (19.2% vs 4.2%, P = 0.192). Thrombotic complications were similar between the DDAVP and non-DDAVP groups (11.1% vs. 8%, P = 1.0). Thirty-nine patients met criteria for hemostatic efficacy analysis. There was no difference in hematoma expansion between the DDAVP and non-DDAVP groups (23.1% vs 34.6%, P = 0.71) and these findings were consistent after adjusting for differences in baseline characteristics (OR 0.63, 95% CI 0.1-3.3). CONCLUSION: The administration of DDAVP was not associated with adverse safety events, but did not significantly reduce the incidence of hematoma expansion in patients with AU-associated ICH.

Responsiveness to DDAVP in Cushing's disease is associated with USP8 mutations through enhancing AVPR1B promoter activity.

PURPOSE: To clarify the characteristics of Cushing's disease (CD) patients who respond to the desmopressin (DDAVP) test and its underlying mechanisms. METHODS: Forty-seven patients with CD who underwent DDAVP testing were included. Patients were divided into two groups: DDAVP test (+) (adrenocorticotropic hormone [ACTH] levels increased by ≥ 1.5-fold during the DDAVP test) and DDAVP test (-) (ACTH levels increased by < 1.5-fold). AVP receptor expression levels in these tumors were quantified using quantitative RT-PCR and immunohistochemistry. AVP receptor promoter activity was analyzed using a dual-luciferase reporter assay system. RESULTS: Females (96.9%) and USP8 mutants (85.7%) were more prevalent in the DDAVP test (+) than in the DDAVP test (-). Indeed, the ACTH and cortisol responsiveness to DDAVP was greater in USP8 mutation positive tumors than that in USP8 wild type tumors (3.0-fold vs. 1.3-fold, 1.6-fold vs. 1.1-fold, respectively). Responsiveness to DDAVP was correlated with the expression levels of AVPR1B, but not with those of AVPR2. Comparably, Avpr1b promoter activity was enhanced by the overexpression of mutant USP8 compared to the wild type. CONCLUSIONS: We found that the responsiveness of ACTH to DDAVP in CD was greater in tumors with USP8 mutations. The present data suggest that USP8 mutations upregulate the AVPR1B promoter activity. Additionally, we showed that the DDAVP test can predict the presence of USP8 mutations.

Application of a TEG-Platelet Mapping Algorithm to Guide Reversal of Antiplatelet Agents in Adults with Mild-to-Moderate Traumatic Brain Injury: An Observational Pilot Study.

BACKGROUND: Traumatic intracranial hemorrhages expand in one third of cases, and antiplatelet medications may exacerbate hematoma expansion. However, the reversal of an antiplatelet effect with platelet transfusion has been associated with harm. We sought to determine whether a thromboelastography platelet mapping (TEG-PM)-guided algorithm could limit platelet transfusion in patients with hemorrhagic traumatic brain injury (TBI) prescribed antiplatelet medications without a resultant clinically significant increase in hemorrhage volume, late hemostatic treatments, or delayed operative intervention. METHODS: A total of 175 consecutive patients with TBI were admitted to our university-affiliated, level I trauma center between March 2016 and December 2019: 54 preintervention patients (control) and 121 patients with TEG-PM (study). After exclusion for anticoagulant administration, availability of neuroimaging and emergent neurosurgery, 62 study patients and 37 control patients remained. Intervention consisted of administration of desmopressin (DDAVP) for nonsurgical patients with significant inhibition at the arachidonic acid or adenosine diphosphate receptor sites. For surgical patients with significant inhibition, dual therapy with DDAVP and platelet transfusion was employed. Study patients were compared with a group of historical controls, which were identified from a prospectively maintained registry and typically treated with empiric platelet transfusion. RESULTS: Median age was 75 years (interquartile range 85-67) and 77 years (interquartile range 81-65) in the TEG-PM and control patient groups, respectively. Admission hemorrhage volumes were similar (10.7 cm3 [20.1] in patients with TEG-PM vs. 14.1 cm3 [19.7] in controls; p = 0.41). There were no significant differences in admission Glasgow Coma Scale, mechanism of trauma, or baseline comorbidities. A total of 57% of controls versus 10% of patients with TEG-PM (p < 0.001) were transfused platelets; 52% of intervention patients and 0% controls were treated with DDAVP. Expansion hemorrhage volumes were not significantly different (14.0 cm3 [20.2] patients with TEG-PM versus 13.6 cm3 [23.7] controls; p = 0.93). There was no significant difference in rates of clinical deterioration, delayed neurosurgical intervention, or late platelet transfusion between groups. CONCLUSIONS: Among patients with hemorrhagic TBI prescribed preinjury antiplatelet therapy, our study suggests that the use of a TEG-PM algorithm may reduce platelet transfusions without a concurrent increase in clinically significant hematoma expansion. Further study is required to prove a causative relationship.

Vasopressin Receptor Type-2 Mediated Signaling in Renal Cell Carcinoma Stimulates Stromal Fibroblast Activation.

Vasopressin type-2 receptor (V2R) is ectopically expressed and plays a pathogenic role in clear cell renal cell carcinoma (ccRCC) tumor cells. Here we examined how V2R signaling within human ccRCC tumor cells (Caki1 cells) stimulates stromal cancer-associated fibroblasts (CAFs). We found that cell culture conditioned media from Caki1 cells increased activation, migration, and proliferation of fibroblasts in vitro, which was inhibited by V2R gene silencing in Caki1 cells. Analysis of the conditioned media and mRNA of the V2R gene silenced and control Caki1 cells showed that V2R regulates the production of CAF-activating factors. Some of these factors were also found to be regulated by YAP in these Caki1 cells. YAP expression colocalized and correlated with V2R expression in ccRCC tumor tissue. V2R gene silencing or V2R antagonist significantly reduced YAP in Caki1 cells. Moreover, the V2R antagonist reduced YAP expression and myofibroblasts in mouse xenograft tumors. These results suggest that V2R plays an important role in secreting pro-fibrotic factors that stimulate fibroblast activation by a YAP-dependent mechanism in ccRCC tumors. Our results demonstrate a novel role for the V2R-YAP axis in the regulation of myofibroblasts in ccRCC and a potential therapeutic target.

The usefulness of the combined high-dose dexamethasone suppression test and desmopressin stimulation test in establishing the source of ACTH secretion in ACTH-dependent Cushing's syndrome.

Bilateral inferior petrosal sinus sampling (BIPSS) is the current gold standard test for differentially diagnosing ACTH-dependent Cushing's syndrome (CS). However, BIPSS is an invasive procedure, and its availability is limited. We retrospectively analysed the 24-hour urinary free cortisol (UFC) level during the high-dose dexamethasone suppression test (HDDST) and plasma ACTH/cortisol levels after the desmopressin stimulation test (DDAVP test) in subjects with confirmed Cushing's disease (CD) (n = 92) and ectopic ACTH-dependent CS (EAS) (n = 16), and evaluated the positive predictive value (PPV) of the two combined-tests in the aetiological diagnosis of ACTH-dependent CS. The percent changes in UFC levels after the HDDST and in ACTH/cortisol levels after DDAVP administration relative to the corresponding basal levels and the area under the receiver operating characteristic (ROC) curve (AUC) were analysed. UFC suppression below 62.7% suggested a pituitary origin with a sensitivity (SE) of 80% (95% CI: 70-88) and a specificity (SP) of 80% (95% CI: 52-96). A threshold increase in the ACTH level after DDAVP stimulation of 44.6% identified CD with an SE of 91% (95% CI: 83-97) and an SP of 75% (95% CI: 48-93). The combination of both tests yielded an SE of 95.5% and PPV of 98.4% for CD, and significantly improved the efficiency of the differential diagnosis between CD and EAS. These dual non-invasive endocrine tests may substantially reduce the need for BIPSS in the etiological investigation of ACTH-dependent CS.

Desmopressin effects on bleeding during functional endoscopic sinus surgery on patients with chronic rhinosinusitis.

OBJECTIVE: In this study we aimed to determine whether Desmopressin (DDAVP) can alter bleeding and improves surgeon visual field and decrease operation time or lessen use of anesthesiology medication in a clinical trial study. METHOD: This study is a randomized clinical trial using the permuted block randomization method. 44 patients were enrolled in study and divided into two equal intervention-control groups. The intervention group received maximum dose of 0/2 micrograms per kg of DDAVP. In the control group, 30 min before the surgery, 100 ml of normal saline will be injected. RESULTS: The amount of bleeding was 517/17 cc in control group during surgery while it was 387/72 cc in group receiving DDAVP which is significantly lower. The satisfaction of surgeon regarding suitable visual field was 6/45 in control group while it was 3/77 in DDAVP receivers which is lower. CONCLUSION: It seems that intravenous DDAVP can reduce bleeding during surgery and offer an enhanced vision for surgeon during surgery but it has no potential efficacy on reduction of period of surgery and need for anesthesiology medication like remifentanil and isoflurane.

Effective hemostasis in children with Von Willebrand factor defects undergoing adenotonsillar procedures.

INTRODUCTION: Children with low von Willebrand factor (VWF) activity or type 1 von Willebrand disease (VWD) have increased risk of bleeding after adenotonsillar procedures and the optimal perioperative management to minimize bleeding is unknown. AIM: To report the effectiveness and safety of an institutional protocol in minimizing postoperative bleeding in children with type 1 VWD or low VWF activity. METHODS: We conducted a retrospective chart review in children with type 1 VWD or low VWF activity treated via an institutional protocol that utilizes repeated doses of Desmopressin acetate (DDAVP, 1-deamino 8-D arginine- vasopressin) or VWF concentrate, brief hospitalization for observation and extended use of oral epsilon aminocaproic acid (EACA). RESULTS: From 2010 to 2017, 13 children underwent an adenotonsillar procedure and were treated with this protocol. Although 7.6% had minor immediate bleeding and 23% had minor delayed bleeding, no patients experienced major bleeding or required transfusion, additional surgery or other measures not specified by the protocol. Mild hyponatremia was observed in 80% of patients who received DDAVP. CONCLUSION: Our institutional protocol specifying repeated dosing of DDAVP or VWF concentrate to sustain elevated VWF levels during periods of highest bleeding risk and extended use of EACA is effective at preventing major bleeding episodes after adenotonsillar procedures. However, this analysis raised safety concerns that prompted changes in the institutional protocol and highlight the need for further prospective studies to determine the optimal strategy for safely reducing bleeding complications in these patients.

Central Diabetes Insipidus in a Preterm Neonate Unresponsive to Intranasal Desmopressin.

Central or neurogenic diabetes insipidus (DI) is uncommon in the pediatric age group and rarely occurs in neonates. It should be suspected in any neonate presenting with excessive urine output and hypernatremia that persists despite increased fluid administration. Diabetes insipidus may be secondary to asphyxia, intraventricular hemorrhage, infection, and structural abnormalities or may be idiopathic or genetic. Diagnosis includes a careful history, laboratory testing, and magnetic resonance imaging. Management of neonatal DI involves a careful balance between fluid intake and pharmacologic treatment. In this article we report a case of an extremely low birth weight infant presenting with central DI possibly caused by abnormality of the pituitary gland. Persistent hypernatremia was the initial presentation. Increased fluids were given initially but were only partially helpful. Eventually subcutaneous desmopressin (DDAVP) was required. The infant was unresponsive to intranasal DDAVP and required subcutaneous DDAVP upon discharge.

Emergency management of patients with bleeding disorders: Practical points for the emergency physician.

Emergency department (ED) physicians are often the first point of contact for patients who present with bleeding symptoms. Work up and management of bleeding in the emergency room can be a daunting task as it requires: (1) accurate diagnosis of the bleeding cause, of which there is long list of common and rare etiologies (2); appropriate investigations and interpretation of the results; and (3) timely management of bleeding symptoms to prevent limb- or life-threatening complications. Crucial to the management of a bleeding patient is a thorough yet focused history exploring bleeding symptoms, medications/drugs (anticoagulants, antiplatelets), mechanism of trauma/injury, personal and family history of diagnosed bleeding disorders or bleeding symptoms and recognizing acuity and severity of bleeding that requires immediate intervention. Physical examination should focus on signs of mucocutaneous versus deep tissue or joint bleeding and assessing for structural lesions that may contribute to bleeding symptoms in patients with known bleeding diathesis. In patients with diagnosed bleeding disorders, emergency care cards will usually outline the initial treatment (e.g. clotting factor replacement, DDAVP) which should be administered before pursuing investigations/imaging studies. Special attention must be paid to the patient with recurrent or unexplained bleeding, or unexplained coagulation studies. There should be a low threshold to consult hematology in these cases and involvement of hematology early in managing patients with bleeding disorders to improve outcomes. This paper is directed toward emergency physicians, pediatricians, and general internists and will highlight key concepts in the primary care and work up of diagnosed and undiagnosed bleeding disorders requiring urgent treatment.

Desmopressin stimulation testing: Response to intravenous and intranasal forms.

INTRODUCTION: Desmopressin is commonly used to reduce bleeding in patients with mucocutaneous bleeding disorders and is available in both intravenous and intranasal forms. Given the variability in response to desmopressin at an individual level, its effectiveness should be assessed with a test dose prior to being advised for use. At this time, no trial has extensively compared the use of intranasal desmopressin to intravenous desmopressin. AIMS: To determine whether both forms of desmopressin are equally effective in yielding a positive response in laboratory assays in paediatric patients with von Willebrand disease or probable von Willebrand disease. METHODS: We evaluated medical record data for 58 patients who underwent desmopressin stimulation testing in our haematology clinic during a 1-year period. Data were collected on demographic information and haematologic laboratory assays prior to desmopressin administration and one hour following desmopressin. RESULTS: There was an absolute increase in von Willebrand antigen to levels appropriate for haemostasis following both forms of desmopressin, although this increase was significantly greater in the intravenous group compared to the intranasal group. There was also a significant absolute increase in Ristocetin Cofactor and Factor VIII levels following desmopressin in both groups. CONCLUSION: Both intravenous and intranasal forms of desmopressin produce a positive response during desmopressin stimulation testing and can be used to identify patients for whom this medication would be effective.

Desmopressin in non-severe haemophilia A: Test-response and clinical outcomes in a single Canadian centre review.

INTRODUCTION: Desmopressin is an effective haemostatic agent for patients with non-severe haemophilia A; however, response may differ between patients of similar severity. Responsiveness is classified based on various cut-off values for plasma levels of FVIII post-desmopressin administration. Patients may be classified differently depending on the values chosen. AIM: To classify desmopressin response in non-severe haemophilia A patients with respect to current test-response definitions. Also, to characterize relationships between test response and clinical outcome of desmopressin use. METHODS: Current desmopressin test-response definitions were obtained from the literature. We adopted peak FVIII level (at 1 hour post-administration) ≥50 IU/dL and <20 IU/dL as complete and no response, respectively, thereby satisfying most reported definitions. Test-responses and clinical outcomes of use between 2007 and 2017 for adult mild/moderate haemophilia A patients were reviewed and correlated. RESULTS: All patients classified as complete responders (n = 31; peak FVIII ≥50 IU/dL) and the majority of partial responders (n = 11; peak FVIII ≥20 to <50 IU/dL) had good clinical outcomes after desmopressin use for a variety of bleeding episodes and procedures. Two non-responders (peak FVIII <20 IU/dL) given desmopressin for minor bleeding/procedures also had good clinical outcomes. One patient with a partial test-response (peak FVIII 23 IU/dL) required additional factor concentrate to achieve haemostasis. CONCLUSIONS: Based on our review, we suggest that the determination of desmopressin responsiveness should consider both the change in plasma FVIII levels as well as clinical outcomes associated with prior therapeutic use.

Claiming desmopressin therapeutic equivalence in children requires pediatric data: a population PKPD analysis.

PURPOSE: For a new formulation of a drug, only pharmacokinetic bioequivalence with the original formulation has to be demonstrated in healthy, young adults. However, "children are not small adults," and to guarantee a safe and effective treatment, age-adapted drug development is required. Desmopressin, a vasopressin analogue prescribed for nocturnal enuresis in children, was studied as an example formulation first developed in adults and then extrapolated to a pediatric indication. METHODS: Population pharmacokinetic and pharmacodynamic modeling was used to analyze previously published desmopressin data of 18 children suffering from nocturnal enuresis. The main objective was the comparison of the therapeutic equivalence of two desmopressin formulations: tablet and lyophilisate. The measurements for pharmacokinetics and pharmacodynamics were respectively plasma desmopressin concentration and urine osmolality and diuresis. RESULTS: The half maximal inhibitory concentration for inhibition of urine production was 0.7 pg/mL lower for the lyophilisate than for the tablet. The effect of formulation on the half maximal inhibitory concentration seems to suggest that the 120-µg lyophilisate has a more pronounced effect on the urine volume and osmolality than the 200-µg tablet, even when the same exposure is achieved. CONCLUSIONS: A new indirect response model for desmopressin was constructed and validated, using a previously built pharmacokinetic model and additional pharmacodynamic data. In order to draw solid conclusions regarding the efficacy and safety of desmopressin in children, pharmacokinetics and pharmacodynamics data should be analyzed together. This study adds proof to potential differences in pediatric and adult pharmacokinetic and pharmacodynamic properties of desmopressin and exemplifies the need for pediatric clinical trials, not only for every new drug but also for every new formulation.

Inherited platelet functional disorders: General principles and practical aspects of management.

Platelets are a critical component for effecting hemostasis and wound healing. Disorders affecting any platelet pathway mediating adhesion, activation, aggregation and procoagulant surface exposure can result in a bleeding diathesis. Specific diagnosis even with advanced techniques which are unavailable to most centers is often difficult. Inherited platelet function disorders therefore represent a heterogeneous and complex collection of disorders with a spectrum of bleeding severity, from relatively mild (and easily missed or misdiagnosed) to severe bleeding phenotype with salient diagnostic features. We advocate the use of bleeding assessment tools to help identification of patients and more importantly for assessment of individual patient bleeding phenotype to guide management decisions for treating and preventing bleeding. The complex management of these patients is best coordinated in a multidisciplinary comprehensive care clinic setting expert in managing bleeding disorders and associated complications, with particular attention to the physical and psychosocial health of patients and their families. Depending on the bleeding phenotype, the location and severity of bleeding, and the nature of an invasive procedure, available treatment modalities range from conservative measures using local pressure, topical thrombin, fibrin sealant, antifibrinolytics etc. to the use of systemic haemostatics such as desmopressin (DDAVP), platelets and recombinant human activated factor VII (rFVIIa). This review will provide opinions on the practical aspects and general management of inherited platelet function disorders, with discussion on the mechanism of action, and the pros and cons of various hemostatic agents. Finally, the prospect of curative treatment for patients with severe bleeding phenotype refractory to available treatments and with poor quality of life will be briefly discussed.

[Effect of Zhenwu Tang on regulating of "AVP-V2R-AQP2" pathway in NRK-52E cells].

This study was aimed to investigate the effect and mechanism of Zhenwu Tang on AVP-V2R-AQP2 pathway in NRK-52E cells in vitro. Forty eight male SD rats were randomly divided into eight groups with 6 animals in each group. Distilled water or 22.68 g·kg⁻¹·d⁻¹ Zhenwu Tang(calculated by raw drug dosage meter) was given by gavage. Blood samples were collected by cardiac puncture， and the medicated serum was centrifuged from the blood by 3 000 r·min⁻¹. NRK-52E cells were treated with different medicated serum or dDAVP. The condition of cell proliferation was detected by RTCA. The distribution of V2R and AQP2 in cells were detected by immunofluorescence. The expression of V2R， PKA and AQP2 were detected by Western blot and AQP2 mRNA level was detected by real-time PCR. Results showed that the level of AQP2 mRNA(P<0.01) and protein expression of V2R， PKA and AQP2(P<0.05， P<0.01， P<0.05) of Z7d group which was treated with Zhenwu Tang medicated serum for 24 h were significantly higher than that of normal rat serum group. And the expression level of V2R， p-AQP2 and AQP2(P<0.01， P<0.05， P<0.01) of Z7d+dDAVP group were significantly increased comparing to normal rat serum group. The results indicate that the applying of Zhenwu Tang medicated serum could increase the expression level of V2R， PKA and AQP2 which exist in AVP-V2R-AQP2 pathway in NRK-52E， and there is synergistic effect between Zhenwu Tang medicated serum and dDAVP. So the pathway of AVP-V2R-AQP2 may be one of the mechanism for which Zhenwu Tang regulate balance of water transportation.

Reset Osmostat: The Result of Chronic Desmopressin Abuse?

A reset osmostat as a cause of hyponatremia can be found in a variety of clinical settings, including pulmonary and neurologic diseases, as well as in physiologic circumstances such as pregnancy. This teaching case describes a 72-year-old white man with a long-standing history of self-medicating with desmopressin acetate (DDAVP) who presented with profound hyponatremia. On discontinuation of DDAVP treatment, he was found to have a reset osmostat. The mild hyponatremia persisted on follow-up. We theorize that the reset osmostat may have developed secondary to long-standing DDAVP use.

Bendamustine-Induced Nephrogenic Diabetes Insipidus in a Patient With AL Amyloidosis.

Nephrogenic diabetes insipidus is a condition characterized by polyuria with dilute urine due to the inability of the principal cells of the renal collecting ducts to respond to antidiuretic hormone and concentrate urine. Nephrogenic diabetes insipidus can be drug induced, and several chemotherapeutic agents have been reported to cause it. Bendamustine is a traditional chemotherapeutic agent being studied for treatment for relapsed systemic AL amyloidosis. We report a case of a 59-year-old man with AL amyloidosis who developed partial nephrogenic diabetes insipidus after receiving bendamustine for treatment of AL amyloidosis. The nephrogenic diabetes insipidus responded well to sodium restriction, hydrochlorothiazide, and desmopressin treatment, allowing the patient to receive subsequent bendamustine cycles without polyuria. Nephrogenic diabetes insipidus resolved shortly after completion of bendamustine therapy.