1,25-Dihydroxyvitamin D3 promotes prostaglandin E1-induced differentiation of HL-60 cells

Human promyelocytic HL-60 cells can be induced by biochemical agents to differentiate in vitro towards divergent types of myelomonocytic cells. It has been reported that prostaglandin E₁ (PGE₁) can induce granulocytic differentiation and that 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) can induce monocytic differentiation. We have now examined the effects of these compounds, both alone and in combination, on HL-60 cell differentiation. PGE₁ (1 g/ml) or 1,25(OH)₂D₃ (10 nM) each inhibited cell proliferation over 48–96 hours of treatment, but combined treatment with both agents was necessary to produce a strong inhibition. The percentage of HL-60 cells that can reduce nitroblue tetrazolium (NBT) (a characteristic index of early monocytic or granulocytic differentiation) increased 13-fold within 72 hours of PGE₁ treatment, and 1,25(OH)₂D₃ produced a fivefold stimulation. However, combined treatment (PGE₁ plus 1,25(OH)₂D₃) produced a dramatic 35-fold increase. HL-60 cells did not produce significant levels of nitric oxide (NO) before 48 hours in culture, and treatment with PGE₁ or 1,25(OH)₂D₃ did not significantly increase cellular NO elaboration over control levels. However, combined treatment produced a striking 12-fold increase over control levels. Similarly, combined treatment was necessary to obtain the maximal time-dependent stimulation of cellular lactate dehydrogenase (LDH) activity (a marker of granulocytic differentiation) as well as acid phosphatase (ACP) activity. During this same period of time, PGE₁, but not 1,25(OH)₂D₃, markedly stimulated cellular claboration of interleukin (IL)-1, IL-6, and tumor necrosis factor (TNF)-, and 1,25(OH)₂D₃ cotreatment strongly augmented these effects. Thus, combined treatment with 1,25(OH)₂D₃ plus PGE₁ generally augmented the apparent conversion of these cells, producing synergistic (multiplicative) or additive effects. Furthermore, PGE₁ induced within 48 hours the more general phenotypic changes classically associated with the differentiation of these cells: increased expression of chloroacetate esterase (ChAE) (a granulocytic marker), decreases in the nuclear/cytoplasmic ratio (characteristic of development beyond the promyelocyte/myelocyte stage), and major alterations in morphology from floating spherical cells to loosely adherent, elliptical polygons. 1,25(OH)₂D₃ had little effect itself on most of these parameters, but augmented the morphological changes induced by PGE₁ treatment. Within 48 hours, the ability of these cells to reduce the tetrazolium salt WST-1, a general measure of cellular metabolic activity, was increased by PGE₁, but not by 1,25(OH)₂D₃; however, the combination of 1,25(OH)₂D₃ and PGE₁ again produced the strongest stimulation. Similarly, only PGE₁ significantly reduced intracellular ATP levels, but combined treatments produced a more pronounced decrease. In summary, our findings suggest that PGE₁, not 1,25(OH)₂D₃, is sufficient to promote rapid in vitro differentiation of HL-60 cells along the granulocytic pathway; however, the PGE₁-induced conversion of these cells is markedly augmented by cotreatment with 1,25(OH)₂D₃. In addition, these converted HL-60 cells preferentially utilize the glycolytic pathway, rather than the citric acid cycle, for production of ATP, a metabolic characteristic that resembles that described for mature granulocytes.     

Laser Doppler velocimetry in retinal arteries of infants

The present study was conducted to assess the feasibility of laser Doppler velocimetry in young infants, as a prelude to ultimately undertaking such measurements in premature infants. A portable, unidirectional laser Doppler velocimeter was developed based on a Kowa RC-2 hand-held fundus camera. Six infants between 1 and 21 weeks of age were studied. Relative red blood cell velocity (f_max) at the centre of retinal arteries was measured over approximately 10 heart cycles. A pulsatility parameter (P=1–f_max.dia/f_max.sys), a summary index of vascular status, was determined from the average diastolic and systolic values of f_max. Velocity waveforms were obtained in four of the six infants. Arterial pulsatility for the group was 0.63±0.13. Precise non-invasive measurement of arterial red blood cell velocity waveforms in young infants was achieved. The high signal-to-noise ratio and temporal resolution of this data suggest that relative measurements of retinal blood flow may permit assessment of haemodynamic changes in premature infants.     

Isolation perfusion in extracorporeal circulation with interleukin-2 and lymphokine-activated killer cells in the treatment of in-transit metastases from limb cutaneous melanoma

Background: Therapies of advanced melanoma patients with interleukin-2 (IL-2) and cytotoxic lymphocytes have produced interesting results, but a larger diffusion of these treatments is limited by the severe side effects due to IL-2 systemic infusion. A strictly regional administration of IL-2 and cells by an isolation perfusion (IP) in extracorporeal circulation (ECC) for the treatment of regional melanoma metastases could improve tolerability and efficacy of this specific modality of immunotherapy. Methods: Ten patients were submitted to adoptive immunotherapy with IL-2 and lymphokine-activated killer (LAK) cells by IP in ECC. The schedule of treatment included the first course of a 5-day systemic administration of IL-2 (Proleukin, EuroCetus 9–12 × 10⁶ IU/M²/day continuous infusion); autologous LAK cells were obtained via leukapheresis and after in vitro activation were given (range 8–28 × 10⁹) along with IL-2 (120-2,400 IU/ml of perfusion priming) to the affected limb by IP; IL-2 (9–12×10⁶ IU/m²/day) was also administered by systemic continuous infusion for 5 days starting on the day after IP. Results: All patients concluded the treatment without any major local or systemic toxicities. Clinical responses included one complete and six partial remissions; three patients had stable disease. All patients are alive. Follow-up after IP ranged from 12 to 35 months (median: 22). The analysis of circulating lymphocytes revealed the rapid disappearance of LAK cells, suggesting their extravasation and/or endothelial adhesion in perfused tissues. Conclusions: IP with IL-2 and LAK cells is a new approach for the treatment of in-transit metastases due to cutaneous melanoma. The treatment appears to be feasible and reliable. Further biological and immunological studies should permit amelioration of the present modality of treatment.     

Test chamber exposure of humans to 1,6-hexamethylene diisocyanate and isophorone diisocyanate

An isocyanate generation apparatus was developed and stable isocyanate atmospheres were obtained. At a concentration of 5 g 1,6-hexamethylene diisocyanate (HDI) per m³ the precision was found to be 7% (n = 5). Three volunteers were each exposed to three different concentrations of HDI (11.9, 20.5, and 22.1 g/m³) and three concentrations of isophorone diisocyanate (IPDI) (12.1, 17.7, and 50.7 g/m³), in an exposure chamber. The duration of the exposure was 2 h. Urine and blood samples were collected, and hydrolysed under alkaline conditions to the HDI and IPDI corresponding amines, 1,6-hexamethylene diamine (HDA) and isophorone diamine (IPDA), determined as their pentafluoropropionic anhydride amides (HDA-PFPA and IPDA-PFPA). The HDA-and IPDA-PFPA derivatives were analysed using liquid chromatography mass spectrometry with thermospray monitoring negative ions. When working up samples from the exposed persons without hydrolysis, no HDA or IPDA was seen. The average urinary excretion of the corresponding amine was 39% for HDI and 27% for IPDI. An association between the estimated inhaled dose and the total excreted amount was seen. The average urinary elimination half-time for HDA was 2.5 h and for IPDA, 2.8 h. The hydrolysis condition giving the highest yield of HDA and IPDA in urine was found to be hydrolysis with 3 M sodium hydroxide during 4 h. No HDA or IPDA could be found in hydrolysed plasma (< ca 0.1 g/l).     

Estimating the human immunodeficiency virus infection curve of intravenous drug users in Lombardia,Italy

We present a model to estimate the infection curve of the human immunodeficiency virus in intravenous drug users in Lombardia. We based estimates on AIDS incidence data, according to a backcalculation model accounting for therapy and changes in the surveillance definition of AIDS.     

Potentiation of stimulus-induced phosphoinositide breakdown by calmodulin antagonists in C6 glioma cells

To investigate the role of calmodulin (CaM)-dependent pathways in agonist-induced phosphoinositide (PI) turnover, the influence of several CaM antagonists on PI-phospholipase C (PLC) activation in intact and permeabilized C₆ glioma cells was examined. The extent of PI turnover was assessed by measuring the accumulation of inositol phosphates (IPs) in the presence of LiCl in C₆ glioma cells prelabelled with myo-[³H]inositol. Trifluoperazine, N-(6-aminohexyl)-5-chloro-l-naphthalenesulphonamide (W7), fendiline and calmidazolium themselves had no effect on basal IP formation, but concentration-dependently (1–30 M) potentiated ATP-, NaF- and A23187-stimulated IP formation. The maximal response to ATP (I mM) was increased by up to 50%, while the concentration for half-maximal effect (EC₅₀, 60 M) as unaffected by trifluoperazine. In digitonin-permeabilized C₆ glioma cells, the concentration-dependent increase of PI-PLC activation elicited by free Ca²⁺ was potentiated by the GTP analogue, guanosine 5-[-thio]triphosphate (GTPS), with an EC₅₀ of 6 M. Trifluoperazine (1–30 M) enhanced the Ca²⁺-stimulated IP formation concentration dependently and this potentiation was counteracted by the addition of CaM. In the combined presence of each CaM antagonist studied and GTPS, an additive increase in IP formation was observed. The results indicate that CaM antagonists enhance stimulus-induced IP formation in C₆ glioma cells primarily by increasing the Ca²⁺-dependent activation of PI-PLC.     

Identification of the central vestibular projections in man: a positron emission tomography activation study

The cerebral representation of space depends on the integration of many different sensory inputs. The vestibular system provides one such input and its dysfunction can cause profound spatial disorientation. Using positron emission tomography (PET), we measured regional cerebral perfusion with various vestibular stimulations to map central vestibular projections and to investigate the cerebral basis of spatial disorientation. We showed that the temporoparietal cortex, the insula, the putamen, and the anterior cingulate cortex are the cerebral projections of the vestibular system in man and that the spatial disorientation caused by unilateral vestibular stimulation is associated with their asymmetric activation.     

一种四点弯曲单向交变应变细胞加载装置的研制

本文根据细胞动力学对力学因素的响应,设计研制了一种四点弯曲单向交变应变加载装置。通过对Wistar大鼠成骨细胞的试验,以及流式细胞仪（FCM）对细胞DNA分析检测的结果,表明研制是成功的,并可广泛使用于内皮细胞、成纤维细胞、平滑肌细胞、心肌细胞等组织工程和生物医学工程、人机工程学、细胞力学方面的研究。     

河南省乡镇卫生院人力资源配置研究

该文在对河南省卫生院人力资源现状调查研究的基础上,分析了乡镇卫生院人力资源配置中存在的主要问题及成困,并从理论与实际相结合的角度,提出了实现卫生院人力资源合理配置的可行性对策。