Selective inhibition of the growth of human erythroid bursts by monoclonal antibodies against transferrin or the transferrin receptor

The relative requirements of colonies derived from erythroid (BFU-E) and myeloid (CFU-c) progenitors for transferrin were examined using monoclonal antibodies directed against the transferrin molecule (TF-6) or its cell surface receptor (TFR-A12, TFR1-2B). Growth of erythroid bursts was profoundly reduced at concentrations of all three antibodies that had no effect on CFU-c-derived colonies. When TFR1-2B was layered over cultures established one to seven days previously, further burst development was inhibited, and degeneration of early erythroid colonies was observed. Addition of erythropoietin augmented transferrin receptor expression on cells harvested after 1 to 2 weeks in culture and analyzed by flow cytometry. Recombinant human erythropoietin gave results comparable to those obtained in experiments using human urinary erythropoietin. Analysis of erythroblasts plucked directly from culture plates confirmed the presence of transferrin receptors on BFU-E-derived colonies. Thymidine incorporation was maximal early in the second week of culture and coincided with high transferrin receptor expression. These data demonstrate that transferrin must be available into the second week of culture to support the growth and differentiation of BFU- E-derived erythroid bursts, that the generation of erythroid colonies from BFU-E is more dependent on transferrin than myeloid colony formation from CFU-c, and that erythropoietin modulates the expression of transferrin receptors on growing bursts.     

Evaluation of AMSA in previously treated patients with acute leukemia: results of therapy in 109 adults

AMSA was evaluated in the treatment of 109 adults with previously treated acute leukemia. Of the 102 evaluable patients, 82 had AML, 17 ALL, and 3 CML in blastic phase. A number of different dose schedules of AMSA were explored, and we conclude that the optimum dose of AMSA for remission induction in acute leukemia is 120 mg/sq m/day for 5 days. Complete remissions were observed in 23 (28%) patients with AML and in 1 patient with ALL. Patients who achieved complete remission were maintained on AMSA using a dose of 30-40 mg/sq m/day for 5 days repeated at 4-wk intervals. The median duration of complete remission was 12 wk (3-59 wk), and the responders survived significantly longer than the failures (27 wk versus 8 wk, p = 0.002). The side effects associated with AMSA therapy included mild nausea and vomiting, stomatitis, diarrhea, phlebitis, alopecia, and myelosuppression-related infections. Our results indicate that AMSA is a useful new antileukemic agent for the treatment of relapsed acute leukemia and appears to have activity comparable to that of the currently available drugs, such as cytarabine and the anthracycline antibiotics.     

GSK1562590, a slowly dissociating urotensin-II receptor antagonist, exhibits prolonged pharmacodynamic activity ex vivo

BACKGROUND AND PURPOSE

Recently identified antagonists of the urotensin–II (U-II) receptor (UT) are of limited utility for investigating the (patho)physiological role of U-II due to poor potency and limited selectivity and/or intrinsic activity.

EXPERIMENTAL APPROACH

The pharmacological properties of two novel UT antagonists, GSK1440115 and GSK1562590, were compared using multiple bioassays.

KEY RESULTS

GSK1440115 (pK_i= 7.34–8.64 across species) and GSK1562590 (pK_i= 9.14–9.66 across species) are high affinity ligands of mammalian recombinant (mouse, rat, cat, monkey, human) and native (SJRH30 cells) UT. Both compounds exhibited >100-fold selectivity for UT versus 87 distinct mammalian GPCR, enzyme, ion channel and neurotransmitter uptake targets. GSK1440115 showed competitive antagonism at UT in arteries from all species tested (pA₂= 5.59–7.71). In contrast, GSK1562590 was an insurmountable UT antagonist in rat, cat and hUT transgenic mouse arteries (pK_b= 8.93–10.12 across species), but a competitive antagonist in monkey arteries (pK_b= 8.87–8.93). Likewise, GSK1562590 inhibited the hU-II-induced systemic pressor response in anaesthetized cats at a dose 10-fold lower than that of GSK1440115. The antagonistic effects of GSK1440115, but not GSK1562590, could be reversed by washout in rat isolated aorta. In ex vivo studies, GSK1562590 inhibited hU-II-induced contraction of rat aorta for at least 24 h following dosing. Dissociation of GSK1562590 binding was considerably slower at rat than monkey UT.

CONCLUSIONS AND IMPLICATIONS

Whereas both GSK1440115 and GSK1562590 represent high-affinity/selective UT antagonists suitable for assessing the (patho)physiological role of U-II, only GSK1562590 exhibited sustained UT residence time and improved preclinical efficacy in vivo.     

Transanal total mesorectal excision achieves equivalent oncologic resection compared to laparoscopic approach,but with functional consequences

BackgroundThis study compared transanal total mesorectal excision (taTME) to laparoscopic total mesorectal excision (laTME) for the treatment of low rectal cancer. Adequacy of oncologic resection as well as postoperative outcomes were analyzed.MethodsWe retrospectively reviewed all proctectomy for low rectal cancer by a single surgeon at our institution from January 2014 to September 2019.ResultsThere were 20 taTME and 30 laTME patients. TaTME patients had more distal tumors with no difference in pathologic resection margins or frequency of positive distal margin. Operative times were longer for taTME, but there were no differences in short-term outcomes or complications. TaTME patients had a higher rate of postoperative fecal incontinence.ConclusionTaTME may be a good option for the most distal tumors, when distal margins may be compromised. TaTME provides equivalent oncologic resection, but there is a higher incidence of postoperative fecal incontinence.     

DERMAL NEUROVASCULAR DYSFUNCTION IN TYPE 2 DIABETES

The present article summarizes recent observations obtained in our laboratory which clearly indicate that sex steroids exert relevant effects on the peripheral nervous system. In particular, the following important points have emerged: (1) Steroids exert stimulatory actions on the synthesis of the proteins proper of the peripheral myelin (e.g., glycoprotein Po and peripheral myelin protein 22) in vivo and on the Schwann cells in culture; (2) in many cases the actions of hormonal steroids are not due to their native molecular forms but rather to their metabolites (e.g., dihydroprogesterone and tetrahydroprogesterone in the case of progesterone; dihydrotestosterone and 5 alpha-androstane-3 alpha,17 beta -diol in the case of testosterone); (3) the mechanism of action of the various steroidal molecules may involve both classical (progesterone and androgen receptors) and nonclassical steroid receptors (GABA, receptor); and finally, (4) the stimulatory action of steroid hormones on the proteins of the peripheral myelin might have clinical significance in cases in which the rebuilding of myelin is needed (e.g., aging, peripheral injury, demyelinating diseases, and diabetic neuropathy).     

早期胚胎心肌细胞兴奋收缩耦联模式

目的　研究胚胎心肌细胞兴奋收缩耦联的机理；方法　使用膜片钳与钙离子浓度分析系统测量酶消化法得到的小鼠胚胎心肌细胞的膜电位与细胞内钙离子浓度；结果　细胚胎心肌细胞存在两种兴奋收缩耦联模式，一种与正常成熟心肌细胞的兴奋收缩耦联模式类似，与细胞膜上的钠通道、L-钙离子通道相关；另一种由细胞内钙振荡诱发，这种钙振荡通过细胞膜上的钠钙交换蛋白引起了细胞膜电位的小幅度变化，该模式是一种更基本的兴奋收缩模式。近似熵分析表明，与后一种模式相比较，前一种模式的规律性更强。结论　胚胎心肌细胞存在两种兴奋收缩耦联模式。     

Effects of intravenous fluid restriction on postoperative complications: comparison of two perioperative fluid regimens: a randomized assessor-blinded multicenter trial

OBJECTIVE: To investigate the effect of a restricted intravenous fluid regimen versus a standard regimen on complications after colorectal resection. SUMMARY BACKGROUND DATA: Current fluid administration in major surgery causes a weight increase of 3-6 kg. Complications after colorectal surgery are reported in up to 68% of patients. Associations between postoperative weight gain and poor survival as well as fluid overload and complications have been shown. METHODS: We did a randomized observer-blinded multicenter trial. After informed consent was obtained, 172 patients were allocated to either a restricted or a standard intraoperative and postoperative intravenous fluid regimen. The restricted regimen aimed at maintaining preoperative body weight; the standard regimen resembled everyday practice. The primary outcome measures were complications; the secondary measures were death and adverse effects. RESULTS: The restricted intravenous fluid regimen significantly reduced postoperative complications both by intention-to-treat (33% versus 51%, P = 0.013) and per-protocol (30% versus 56%, P = 0.003) analyses. The numbers of both cardiopulmonary (7% versus 24%, P = 0.007) and tissue-healing complications (16% versus 31%, P = 0.04) were significantly reduced. No patients died in the restricted group compared with 4 deaths in the standard group (0% versus 4.7%, P = 0.12). No harmful adverse effects were observed. CONCLUSION: The restricted perioperative intravenous fluid regimen aiming at unchanged body weight reduces complications after elective colorectal resection.     

Hemorrhage and operation cause a contraction of the extracellular space needing replacement--evidence and implications? A systematic review

BACKGROUND: Hemorrhagic hypotension or operative trauma is believed to cause a contraction of the extracellular fluid volume (ECV) beyond the measured fluid losses. The aim of this review was to explore the evidence and implications of ECV loss. METHODS: We performed a systematic review of original trials measuring ECV changes during hemorrhage or operation. PubMed, relevant periodicals, and reference lists were searched until no further original articles appeared. The quality of both the scientific and the technical methods of the trials were evaluated. RESULTS: A total of 61 original articles were found. The pattern appeared that all investigators reporting shock or operation to cause a disparate reduction of the ECV had measured the ECV with the same method. The ECV was calculated from very few blood samples that were withdrawn after 20 to 30 minutes of equilibration of a tracer (the (35)SO(4)-tracer). Trials calculating ECV from multiple blood samples, after longer equilibration times, or using other tracers did not find a contraction of the ECV. On the contrary, trials using a bromide tracer found the ECV to be expanded after operation. CONCLUSIONS: The evidence supporting the idea that hemorrhage or operation cause a contraction of the ECV is weak, and probably a result of flawed methodology.     

Influence of postoperative enteral nutrition on cellular immunity. A random double-blinded placebo controlled clinical trial

Purpose  

The aim of this study was to discover if the cellular immunological response is different in patients receiving early postoperative enteral nutrition compared to patients who only receive “water”.