Evaluation of dexamethasone for the treatment of intracerebral hemorrhage using a collagenase-induced intracerebral hematoma model in rats

Dexamethasone was evaluated for the treatment of intracerebral hemorrhage using a rat model of cerebral hematoma induced by intracerebral injection of collagenase. The treatment group consisted of hematoma rats receiving dexamethasone 1 mg/kg intraperitoneal (i.p.) at 1 and 24 h following surgery. Controls included hematoma rats receiving saline i.p. and sham-operated animals receiving saline i.p. Each animal was evaluated neurologically prior to, as well as 24 and 48 h following surgery. After the last neurological evaluation, animals were deeply anesthetized and the brain was removed following perfusion for microscopic examination and glial fibrillary acidic protein immunohistochemistry. Behavioral scores were significantly improved in the treated group (P < 0.0001). The hematoma volume was significantly smaller (P < 0.02). Neutrophils and astrocytes were less numerous in the hematoma of dexamethasone-treated animals (P < 0.001), however the number of necrotic neurons in the penumbra was not changed by the treatment. The number of necrotic neurons in the cerebral cortex was less in treated than in nontreated animals (P < 0.01). Controls had many vascular changes including necrotic endothelium and fibrin deposits compared with treated animals. In conclusion, dexamethasone administered shortly after an intracerebral hematoma appears beneficial for the treatment of this condition.     

High doses of methylprednisolone are required for the treatment of collagenase-induced intracerebral hemorrhage in rats

Methylprednisolone (MP) was evaluated for the treatment of intracerebral hemorrhage in a Sprague-Dawley rat model of cerebral hematoma induced by subcortical injection of collagenase. At 1 and 24 h after the injection, MP was administered intraperitoneally (IP) at a concentration of 10, 35, or 100 mg/kg. Control groups received saline IP at 1 and 24 h after the intracerebral injection of collagenase (positive controls) or saline (negative controls). Motor behaviour 24 h before and 24 h and 48 h after the intracerebral injection was evaluated by means of a neurologic exam and a rotarod treadmill test. The animals were euthanized at 48 h; brain water content was determined in half of the rats, and histopathological studies were done in the other half. Compared with the positive controls, the animals with collagenase-induced hematoma performed significantly better on the neurologic exam after treatment with 100 mg/kg of MP and on the rotarod test after treatment with 35 or 100 mg/kg of MP. The hematoma volume was significantly smaller (P < 0.002) after all doses of MP; however, the smallest volume was seen with 100 mg/kg. There were significantly fewer neutrophils (P < 0.01) within the hematoma in the MP-treated animals (maximum reduction with 100 mg/kg) than in the positive controls, but the numbers of reactive astrocytes did not differ significantly between the treatment groups. The number of necrotic neurons in the penumbra did not differ between the treatment groups; however, there were significantly fewer (P < 0.005) in the cerebral cortex in the group treated with 100 mg/kg of MP compared with the positive controls. These results suggest that high doses of MP administered shortly after occurrence of a cerebral hematoma are beneficial for the treatment of intracerebral hemorrhage.     

Synchronisation of lambing with low doses of dexamethasone in Chios ewes--short communication

The purpose of the present study was to investigate the feasibility of improving the synchronisation of lambing after oestrus synchronisation and artificial insemination (AI). To this end, low doses of dexamethasone 21-isonicotinate (DEX) alone or in combination with prostaglandin F2a (PG) were used in five treated groups (n = 20 each) and one control group (n = 136) of Chios ewes. On day 143 of pregnancy 1.5 mg DEX was given in Group 5, while on day 146 the following treatments were applied: 0.0375 mg PG in Groups 4 and 5, and 1, 1.5 and 2 mg of DEX in ewes of Groups 1, 2 and 3, respectively. The control ewes received no treatment. The 1.5 and 2 mg dose of DEX was more effective in synchronising labour as regards the treatment to lambing interval and the proportion of ewes that gave birth within 3 days. However, obstetrical manipulations were needed, and dead lambs were born when 2 mg DEX was used. It was concluded that lambing can be safely synchronised in Chios ewes with 1.5 mg DEX given on day 146, without affecting the viability of lambs and without parturition complications.     

Effects of anabolic and therapeutic doses of dexamethasone on thymus morphology and apoptosis in veal calves

Three groups of 10 veal calves were treated, respectively, with 5 mg of dexamethasone-21-isonicotinate administered intramuscularly on days 0 and 7 (group A); 0.4 mg/day of dexamethasone-21-phosphate administered orally for 20 days (group B); or left untreated as controls (group C). Two animals from each group were slaughtered on day 3, 7, 14, 32 and 52. The size and weight of the thymus decreased progressively in both treated groups until day 32. On day 14, in comparison with the controls, there was a mean reduction of 76 per cent in the thymus weight of group A and 35 per cent in group B. On day 32, the reductions were 13 per cent in group A and 50 per cent in group B, but the thymus weight of both groups had recovered completely by day 52. Dexamethasone-induced changes in thymus weight associated with lymphoid depletion and fat replacement, and there were clear correlations between these changes and apoptosis of thymocytes.     

Nicotinamide attenuates the decrease of astrocytic phosphoprotein PEA-15 in focal cerebral ischemic injury

Nicotinamide exerts neuroprotective effects against focal cerebral ischemic injury. Phosphoprotein enriched in astrocytes 15 (PEA-15) is prominently expressed in astrocytes that exert broad anti-apoptotic functions. This study investigated whether nicotinamide modulates PEA-15 and levels of two phosphorylated PEA-15 (Serine 104 and 116) in an animal model of middle cerebral artery occlusion (MCAO)-induced injury. Adult male rats were treated with vehicle or nicotinamide (500 mg/kg) 2 hr after the onset of MCAO and cerebral cortices were collected at 24 hr after MCAO. In a proteomic approach, MCAO induced decreases of PEA-15 levels, while nicotinamide treatment attenuated the injury-induced decrease in PEA-15. The results of Western blot analysis suggest that nicotinamide prevented injury-induced reduction in phospho-PEA-15 (Serine 104) and phospho-PEA-15 (Serine 116) levels. The phosphorylation of PEA-15 exerts anti-apoptotic functions, and reduction of PEA-15 phosphorylation leads to apoptotic cell death. These results suggest that nicotinamide exerts a neuroprotective effect by attenuating the injury-induced decreases of PEA-15 and phospho-PEA-15 (Ser 104 and Ser 116) proteins.     

Clinical oral doses of dexamethasone decreases intrinsic clearance of quinidine, a cytochrome P450 3A substrate in dogs

We investigated the effect of dexamethasone (DEX) at clinical doses on the pharmacokinetics of quinidine (QN) in dogs. Dogs (5 healthy 1-year-old male beagles) were orally administered DEX once daily for 5 days at 2.5 or 7.5 mg/day. QN (2 mg/kg) was intravenously injected 3 weeks before and one day after the DEX treatment. The plasma concentration of QN was determined by high-performance liquid chromatography with fluorometric detection. Plasma concentrations of albumin and alpha(1)-acid glycoprotein (AGP) were determined by a bromocresol green method and a single immunodiffusion method, respectively. In order to calculate unbound concentrations of QN in plasma, the binding kinetics of QN in plasma was examined by an ultrafiltration method using pooled plasma from the 5 dogs when they were drug-free. Total body clearance of QN was decreased dose-dependently By the DEX treatment, although the decrease was not statistically significant. Elimination half-lives significantly increased (more than twice at 7.5 mg), and intrinsic clearance significantly decreased (about 50%). The volume of distribution increased significantly (about two-fold). Plasma levels of AGP significantly decreased, and the unbound fraction of QN in plasma significantly increased. Our results demonstrate that clinical doses of DEX significantly affect the pharmacokinetics of QN, a CYP3A substrate in dogs, by decreasing CYP3A activity and plasma AGP levels. There is a possibility that adverse drug-drug interaction occurs during DEX therapy through its effects on CYP3A activity and plasma AGP levels.     

Low doses of estradiol partly inhibit release of GH in sheep without affecting basal levels

Estradiol increases basal growth hormone (GH) concentrations in sheep and cattle. This study sought to determine the effects of estradiol on GH-releasing hormone (GRH)-stimulated GH release in sheep. Growth hormone secretory characteristics, the GH response to GRH, and steady-state GH mRNA concentrations were determined in castrated male lambs treated with 2 different doses of estradiol 17-β for a 28-d experimental period. Although no differences between treatments in mean GH, basal GH, or GH pulse number were observed after 28 d of estradiol treatment, GH pulse amplitude was greater (P < 0.05) in the 2.00-cm implant-treated animals than in the control and 0.75-cm implant group. The effect of estradiol treatment on GRH-stimulated GH release revealed differences between the control and estradiol-treated animals (P < 0.05). The 15-min GH responses to 0.075 μg/kg hGRH in the control, 0.75-cm, and 2.00-cm implant groups, respectively, were 76 ± 10, 22.6 ± 2.1, and 43.6 ± 15.0 ng/mL. Growth hormone mRNA content was determined for pituitary glands from the different treatment groups, and no differences in steady-state GH mRNA levels were observed. There were no differences in the mean plasma concentrations of IGF-I, cortisol, T₃, or T₄ from weekly samples. Growth hormone release from cultured ovine pituitary cells from control sheep was not affected by estradiol after 72 h or in a subsequent 3-h incubation with estradiol combined with GRH. These data suggest that estradiol has differing actions on basal and GRH-stimulated GH concentrations in plasma, but the increase in pulse amplitude does not represent an increased pituitary sensitivity to GRH.     

Effects of single intravenous doses of dexamethasone on baseline plasma cortisol concentrations and responses to synthetic ACTH in healthy dogs

The duration of adrenocortical suppression resulting from a single IV dose of dexamethasone or dexamethasone sodium phosphate was determined in dogs. At 0800 hours, 5 groups of dogs (n = 4/group) were treated with 0.01 or 0.1 mg of either agent/kg of body weight or saline solution (controls). Plasma cortisol concentrations were significantly (P less than 0.01) depressed in dogs given either dose of dexamethasone or dexamethasone sodium phosphate by posttreatment hour (PTH) 2 and concentrations remained suppressed for at least 16 hours. However, by PTH 24, plasma cortisol concentrations in all dogs, except those given 0.1 mg of dexamethasone/kg, returned to control values. Adrenocortical suppression was evident in dogs given 0.1 mg of dexamethasone/kg for up to 32 hours. The effect of dexamethasone pretreatment on the adrenocortical response to ACTH was studied in the same dogs 2 weeks later. Two groups of dogs (n = 10/group) were tested with 1 microgram of synthetic ACTH/kg given at 1000 hours or 1400 hours. One week later, half of the dogs in each group were given 0.01 mg of dexamethasone/kg at 0600 hours, whereas the remaining dogs were given 0.1 mg of dexamethasone/kg. The ACTH response test was then repeated so that the interval between dexamethasone treatment and ACTH injection was 4 hours (ACTH given at 1000 hours) or 8 hours (ACTH given at 1400 hours). Base-line plasma cortisol concentrations were reduced in all dogs given dexamethasone 4 or 8 hours previously.(ABSTRACT TRUNCATED AT 250 WORDS)     

水中溶氧量测试系统的设计

本文依据溶氧传感器DOB-300B的工作原理,以STC12C5410AD单片机为控制核心,设计了水质溶氧测试系统。在此系统中,采用溶氧探头检测水质中的溶氧量,并将水中溶氧量相对应的电信号传送给单片机,以便单片机对接收到的溶氧信号进行采集及数据的处理。此外,可通过按键对溶氧数值的上下限数值进行设定,若溶氧量的数值不在设定的数值范围内,可驱动蜂鸣器报警。     

Estimating the endogenous water content of frozen eviscerated duck carcasses

1. Statistical analysis of data from a small sample of duck carcasses, ranging in weight from 1.1 to 2.2 kg, which had been bled, wet‐plucked and eviscerated and from which the heads and feet had been removed, but which had not subsequently been through a spray, slush‐tank or spin‐chiller before being frozen, showed that the water content could be predicted from knowledge of the protein content alone.

2. The standard deviation of the difference between the predicted amount of water and the amount found by analysis of an independent sample of carcass homogenate was 1.8% of the mean carcass weight.

3. Accuracy of prediction was scarcely affected by taking account of the mineral content of the carcass and was unaffected by fat content.     

高温胁迫对香根草含水量、膜透性、脯氨酸和叶绿素含量的影响

研究了高温胁迫条件下香根草相对含水量、膜透性、脯氨酸和叶绿素含量的变化规律。结果表明:25~40℃处理24 h后香根草的膜透性、脯氨酸含量逐渐上升,相对含水量、叶绿素含量逐渐下降,但幅度不大;40℃以上高温处理后,以上生理指标均有显著变化。与常温25℃比较,温度每升高5℃,膜透性、脯氨酸含量平均增加27.5%和86.0%,而相对含水量和叶绿素含量分别下降5.5%和10.1%。在试验条件下,香根草生长的最适温度为25~35℃,45℃为临界温度上限,55℃为致死温度上限。     

民勤10种典型荒漠植物冠层光谱与含水率的特征分析

植物体内水分是影响植物光合作用、呼吸作用、生物量及其他生理生化指标的主要因素之一,植物含水率的调查是植被研究的重要内容,利用高光谱进行典型荒漠植物含水率与冠层光谱的关系研究对荒漠区植被遥感监测具有重要意义。本研究借助ASD便携地物光谱仪实地测定了10种典型荒漠植物的冠层光谱曲线,并采用相关系数法和植被指数法,分析了不同荒漠植物光谱特征及其与冠层含水率的关系,结果显示:1)荒漠植物反射光谱曲线具有绿色植物在可见光-近红外波段的普遍特征,有明显的"绿峰"特征和"红边效应"。2)在954-973,1 184-1 198和1 440-1462 nm三个波段,荒漠植物存在明显的水分吸收谷。其中,1 440-1 462 nm波段的光谱反射率与含水率相关系数大于0.8,二者具有很强的线性相关性。3)WBI(Water Band Index)、NDWI(Normalized Difference Water Index)、NDII(Normalized Difference Infrared Infrared Index)、MSI(Moisture Stress Index)与植物含水率显著相关(P<0.05),冠层水分含量指数与植被水分实测值具有较高的一致性,可以反映荒漠植被含水率变化。     

相对湿度对破壁蜂花粉水分含量的影响

为了研究相对湿度对破壁蜂花粉水分含量的影响,在20~25℃室温条件下,基于不同的空气相对湿度,经过分析破壁蜂花粉水分含量随敞放时间的变化规律,获得了蜂花粉的最佳加工环境。结果表明,空气相对湿度为10%的条件对蜂花粉有着干燥的作用;当周围环境的相对湿度大于35%时,蜂花粉吸潮较为明显,不利于生产、加工和贮藏;而当相对湿度在30~35%之间时,综合考虑各方面因素的影响,此为生产破壁蜂花粉最佳环境。     

Breed difference in water content of faeces from five breeds of sheep

Water content of faeces from five breeds was examined (14 weekly observations — eight sheep of each breed). A higher water content was found of faeces from New Zealand Romney Marsh than from their pasture mates of breeds originating from drier areas — Somali, Merino, Karakul; but Nandi originating from a medium to wet area had a similar dry matter content of faeces as the dry area breeds mentioned above. The growth rate in New Zealand Romney Marsh is greater than in the other breeds.     

Effect of oral administration of clinically relevant doses of dexamethasone on regulation of cytochrome P450 subfamilies in hepatic microsomes from dogs and rats

OBJECTIVE: To evaluate the effect of oral administration of dexamethasone (DEX) at clinically relevant doses on metabolic activities of cytochrome P450 (CYP) isoenzymes in dogs and rats. ANIMALS: 15 healthy 1-year-old male Beagles and 20 healthy 10-week-old male Wistar rats. PROCEDURE: Hepatic microsomes were harvested from dogs treated orally with DEX at 2.5 and 7.5 mg for 5 days and from rats treated orally with DEX at 0.75, 6, and 48 mg/kg for 5 days. 7-ethoxyresorufin, tolbutamide, bufuralol, and midazolam were used as CYP1A, CYP2C, CYP2D, and CYP3A substrates, respectively. Concentrations of metabolites formed by CYPs were measured by use of high-performance liquid chromatography, except for the resorufin concentrations measured by use of a fluorometric method. Reaction velocity-substrate concentration data were analyzed to obtain maximum reaction velocity (Vmax) and Michaelis-Menten constant (Km). RESULTS: Values of Vmax for midazolam 4-hydroxylation were significantly decreased by treatment with DEX at 2.5 and 7.5 mg in dogs, although values of Km were not affected. Values of Vmax for bufuralol 1'-hydroxylation were also decreased by treatment with DEX. In rats, values of Vmax for midazolam 4- hydroxylation were significantly decreased by treatment with DEX at 0.75 and 6 mg/kg but significantly increased at 48 mg/kg. Other reactions were not affected by treatment with DEX. CONCLUSIONS AND CLINICAL RELEVANCE: Our results indicate that DEX downregulates the CYP3A subfamily when administered at clinically relevant doses to dogs. The effect of downregulation of CYP3A in dogs treated with DEX should be considered to avoid adverse effects from coadministration of drugs.     

温度和水分含量对四种蜂蜜结品的影响

蜂蜜结晶是长期困扰蜂业的一大难题.本文对不同温度和蜂蜜含水量对蜂蜜结晶的影响进行研究,结果如下:在9℃～15℃的范围内,枇杷蜜、荔枝蜜、鹅掌柴蜜(冬蜜)、桂花蜜最容易结晶的温度是9℃～11℃.枇杷蜜最容易结晶的含水量是20.75%～23.75%,结晶范围是20.75%～26.75%.桂花蜜最容易结晶的含水量是25.75%～29.75%,但是结晶范围较广,在15.75%～29.75%均出现了结晶现象.冬蜜最容易结晶的含水量是20.75%～22.75%,结晶范围是19.75%～25.75%.荔枝蜜最容易结晶的含水量是20.75%～23.75%,结晶范围是20.75%～27.75%.     

Bioelectrical impedance analysis determination of water content and distribution in the horse

A horse’s hydration status is critical to its health. The accurate and quantitative determination of it has been problematic because of size, length and density of hair, and uneven topography. The objective of this study was to validate a bioelectrical impedance analysis (BIA) method for objectively quantifying hydration status. Monofrequency BIA values and simple biometric measurements were used to construct predictive equations for total body water, plasma, extracellular, and intra-cellular fluid volumes. These predictive equations were correlated with standard body fluid dilution reference methods. The result was an accuracy of ±0.64% for total body water, ±0.17% for plasma volume, ±1.91% for extra-cellular fluid, and ±0.57% for intra-cellular fluid compartments. Less than 5 min was required for all of the measurements and determinations. Therefore, it appears that an accurate measurement of body fluid distribution can be performed on horses using a fast, easy, non-invasive, inexpensive BIA method.     

噻环乙胺对大鼠不同脑区cGMP含量的动态影响

为探讨环鸟苷酸(cGMP)在噻环乙胺全麻分子学机理中可能的作用,48只SD大鼠,随机均分为对照组、麻醉组、恢复Ⅰ组和恢复Ⅱ组,用放射免疫法分别测定各脑区的cGMP含量.结果显示,大鼠腹腔注射噻环乙胺30mg/kg后,麻醉组大脑皮层、海马、丘脑的cGMP含量明显降低,分别较对照组降低了35.30%(P<0.01),26.48%(P<0.01),40.67%(P<0.01),而在恢复Ⅰ组和恢复Ⅱ组cGMP含量明显恢复(与对照组相比,P>0.05).在噻环乙胺麻醉全过程中脑干、小脑的cGMP含量未发生明显的变化.这表明,cGMP参与了噻环乙胺全麻作用产生的分子学机理的调控,噻环乙胺全麻作用可能与抑制大脑皮层、海马和丘脑等脑区cGMP释放有关.     

Relationship of protein concentration and water content of equine serum and plasma samples

A highly significant correlation between the water content and protein concentration of equine serum and plasma samples was demonstrated over a wide range of concentrations. A close correlation was also observed between protein concentration as estimated by refractometry and as determined by the biuret procedure for equine serum and plasma samples.