Transdermal cannabidiol reduces inflammation and pain-related behaviours in a rat model of arthritis

BACKGROUND

Current arthritis treatments often have side-effects attributable to active compounds as well as route of administration. Cannabidiol (CBD) attenuates inflammation and pain without side-effects, but CBD is hydrophobic and has poor oral bioavailability. Topical drug application avoids gastrointestinal administration, first pass metabolism, providing more constant plasma levels.

METHODS

This study examined efficacy of transdermal CBD for reduction in inflammation and pain, assessing any adverse effects in a rat complete Freund's adjuvant-induced monoarthritic knee joint model. CBD gels (0.6, 3.1, 6.2 or 62.3 mg/day) were applied for 4 consecutive days after arthritis induction. Joint circumference and immune cell invasion in histological sections were measured to indicate level of inflammation. Paw withdrawal latency (PWL) in response to noxious heat stimulation determined nociceptive sensitization, and exploratory behaviour ascertained animal's activity level.

RESULTS

Measurement of plasma CBD concentration provided by transdermal absorption revealed linearity with 0.6-6.2 mg/day doses. Transdermal CBD gel significantly reduced joint swelling, limb posture scores as a rating of spontaneous pain, immune cell infiltration and thickening of the synovial membrane in a dose-dependent manner. PWL recovered to near baseline level. Immunohistochemical analysis of spinal cord (CGRP, OX42) and dorsal root ganglia (TNFα) revealed dose-dependent reductions of pro-inflammatory biomarkers. Results showed 6.2 and 62 mg/day were effective doses. Exploratory behaviour was not altered by CBD indicating limited effect on higher brain function.

CONCLUSIONS

These data indicate that topical CBD application has therapeutic potential for relief of arthritis pain-related behaviours and inflammation without evident side-effects.

Osteochondrogenic potential of marrow mesenchymal progenitor cells exposed to TGF-beta 1 or PDGF-BB as assayed in vivo and in vitro

Mesenchymal progenitors cells can be isolated from rat bone marrow and mitotically expanded in vitro. When these cells, which we operationally call mesenchymal stem cells (MSCs), are placed in an appropriate environment, they have the capacity to differentiate into bone and/or cartilage. This capacity is called osteochondrogenic potential. In this study, preconfluent MSCs were exposed in vitro to 5 ng/ml transforming growth factor-beta 1 (TGF-beta 1) or platelet-derived growth factor, isoform BB (PDGF-BB) for a pulse of 48 h and assayed for cell proliferation, alkaline phosphatase activity, and osteochondrogenic potential; untreated MSC's served as controls. In these cell culture conditions, TGF-beta 1 or PDGF-BB had similar effects on proliferation and alkaline phosphatase activity. Both growth factors increased cell proliferation and decreased alkaline phosphatase activity of MSCs. Sister cultures of TGF-beta 1- or PDGF-BB-treated MSCs and untreated MSCs were trypsinized. For each type of culture, the trypsinised MSCs were split in two parts: one part was replated in an osteogenic medium to assess its in vitro osteogenic potential, whereas the other part was seeded into porous calcium phosphate ceramics and implanted subcutaneously in syngeneic rats to assess its in vivo osteochondrogenic potential. PDGF-pretreated MSCs showed no difference in in vivo and in vitro osteochondrogenesis from that of control MSCs, while TGF-beta 1 pretreatment blocked the osteochondrogenic potential of MSCs when assayed in vitro for bone nodule formation. However, when tested in vivo, TGF-beta 1-pretreated MSCs were able to form bone and cartilage. These data show that measurements of proliferation and alkaline phosphatase activity of preconfluent MSCs immediately after exposure to growth factor were not predictive of their subsequent osteochondrogenic potential. Moreover, the variation of the osteochondrogenic potential of MSCs after exposure to growth factor was further modulated by the environment in which the MSCs were assayed.

Triphalangeal thumb-polysyndactyly syndrome and syndactyly type IV are caused by genomic duplications involving the long range, limb-specific SHH enhancer

BACKGROUND

The Sonic hedgehog (SHH) protein produced in the zone of polarising activity (ZPA) is a major determinant of the identity and numbers of digits in early limb development. Preaxial polydactyly types II (PPD2) and III (PPD3) have been mapped to a critical region at 7q36, and subsequently shown to be caused by point mutations in the ZPA regulatory sequence (ZRS), a long range cis-regulator for the SHH gene. Triphalangeal thumb-polysyndactyly syndrome (TPTPS) and syndactyly type IV (SD4) were also mapped to the 7q36 region but pathogenic mutations in ZRS have not yet been affirmed.

METHODS AND RESULTS

We performed linkage and haplotype analysis in six Han Chinese families with TPTPS and/or SD4, and refined the disease locus to an interval of 646 kb containing ZRS. In all families, the affected individuals heterozygous at rs10254391 (a single nucleotide polymorphism within ZRS) revealed a remarkable allele imbalance on sequence chromatogram. Using real-time quantitative polymerase chain reaction (qPCR), we identified duplication of ZRS and found that this duplication segregated with the limb phenotypes in all families but was not detected in unaffected family members or in unrelated control individuals. The duplication was also confirmed by interphase fluorescence in situ hybridisation (FISH) in an affected individual. We designed 17 additional qPCR assays and defined the minimum duplications in all six families, ranging from 131kb to 398kb.

CONCLUSION

Both TPTPS and SD4 are due to duplications involving ZRS, the limb specific SHH enhancer. Point mutations in the ZRS and duplications encompassing the ZRS cause distinctive limb phenotypes.

Docetaxel-cisplatin might be superior to docetaxel-capecitabine in the first-line treatment of metastatic triple-negative breast cancer

BACKGROUND

Triple-negative breast cancer (TNBC) may be more sensitive to platinum. This study was to compare platinum-based regimen with nonplatinum regimen in the first-line treatment of advanced TNBC.

PATIENTS AND METHODS

Eligible metastatic TNBC (mTNBC) women without prior treatment for advanced disease were randomized (1 : 1) to receive either docetaxel-cisplatin (TP) or docetaxel -capecitabine (TX) q3w for up to 6 cycles, until disease progression or unacceptable toxicity. The primary end point was objective response rate (ORR) and the secondary end points included progression-free survival (PFS) and overall survival (OS). In total 53 patients were enrolled.

RESULTS

The median follow-up was 24 months. ORR was higher in the TP group than in the TX group (63.0% versus 15.4%, P = 0.001). PFS was more than doubled (10.9 months versus 4.8 months, P < 0.001) and median OS was also greatly improved (32.8 months versus 21.5 months, P = 0.027). Toxic effects were not different except G3/4 vomiting and G2/3 hand-foot syndrome.

CONCLUSIONS

This study suggested that cisplatin-based chemotherapy was superior to capecitabine-based regimen in the first-line treatment of mTNBC, as measured by ORR, PFS and OS. Further large-scale study should be warranted. These results are not sufficient to change clinical practice.

Comparison of the radical trapping ability of PBN, S-PPBN and NXY-059

The nitrones alpha-phenyl-N-tert-butyl nitrone (PBN), sodium 2-sulfophenyl-N-tert-butyl nitrone (S-PBN) and disodium 2,4-disulfophenyl-N-tert-butyl nitrone (NXY-059) are neuroprotective in a variety of rodent models. The objective of the current studies was to compare the ability of PBN, S-PBN, and NXY-059 to form radical adducts and to prevent salicylate oxidation in an aqueous system. For the electron spin resonance (ESR) studies, hydroxyl radicals were generated with ultraviolet (UV) light and hydrogen peroxide. Secondary radicals were then produced by the addition of methanol, ethanol, isopropanol, dimethylsulfoxide, tetrahydrofuran or 1,4-dioxane. In addition, competition spin trapping studies were performed using PBN-alpha-(13) C and either S-PBN or NXY-059. In the salicylate studies, PBN, S-PBN and NXY-059 were compared to a variety of other antioxidants and reference compounds (cysteine, glutathione, ascorbate, uric acid, Tempo, Trolox, and Tirilizad) for their ability to prevent 2,3- and 2,5-dihydroxybenzoic acid formation induced by hydroxyl radical generating systems. All 3 nitrones trapped carbon- and oxygen-centered radicals to produce ESR-detectable radical adducts. Each nitrone also prevented salicylate oxidation, with PBN being the most effective. The ability of these 3 nitrones to prevent salicylate oxidation resembled that of most of the other compounds tested.

Molecular cloning of Porimin, a novel cell surface receptor mediating oncotic cell death

Anti-Porimin (Pro-oncosis receptor inducing membrane injury) mAb mediates oncosis-like cell death in Jurkat cells. Porimin cDNA was isolated from a Jurkat cell cDNA library by COS cell-expression cloning. The 3,337-bp cDNA has an ORF of 567 bp, encoding a type I transmembrane protein of 189 amino acids. The extracellular domain of Porimin contains many O-linked and seven N-linked glycosylation sites that define it as a new member of the mucin family. COS7 and 293 cells transiently transfected with Porimin cDNA were specifically recognized by anti-Porimin Ab in cell staining and immunoblotting experiments. When expressed in Jurkat cells, a His-tagged Porimin cDNA construct resulted in the generation of a specific 110-kDa-size protein that matched the molecular mass of the endogenous Porimin protein. Crosslinking of the Porimin receptor expressed on COS7 transfectants resulted in the loss of cell membrane integrity and cell death as measured by the leakage of intracellular lactate dehydrogenase. Both COS7 and 293 cells expressing transfected Porimin at a relatively high level lost their ability to adhere to culture dishes, suggesting a role for Porimin in cell adhesion. The Porimin gene was mapped to human chromosome 11q22.1 and is composed of four exons spanning 133 kb of genomic DNA.

Effect of long-term exposure to fluoride in drinking water on risks of bone fractures

Findings on the risk of bone fractures associated with long-term fluoride exposure from drinking water have been contradictory. The purpose of this study was to determine the prevalence of bone fracture, including hip fracture, in six Chinese populations with water fluoride concentrations ranging from 0.25 to 7.97 parts per million (ppm). A total of 8266 male and female subjects > or =50 years of age were enrolled. Parameters evaluated included fluoride exposure, prevalence of bone fractures, demographics, medical history, physical activity, cigarette smoking, and alcohol consumption. The results confirmed that drinking water was the only major source of fluoride exposure in the study populations. A U-shaped pattern was detected for the relationship between the prevalence of bone fracture and water fluoride level. The prevalence of overall bone fracture was lowest in the population of 1.00-1.06 ppm fluoride in drinking water, which was significantly lower (p < 0.05) than that of the groups exposed to water fluoride levels > or =4.32 and < or =0.34 ppm. The prevalence of hip fractures was highest in the group with the highest water fluoride (4.32-7.97 ppm). The value is significantly higher than the population with 1.00-1.06 ppm water fluoride, which had the lowest prevalence rate. It is concluded that long-term fluoride exposure from drinking water containing > or =4.32 ppm increases the risk of overall fractures as well as hip fractures. Water fluoride levels at 1.00-1.06 ppm decrease the risk of overall fractures relative to negligible fluoride in water; however, there does not appear to be similar protective benefits for the risk of hip fractures.

Lengthening of the gastrocnemius-soleus complex: an anatomical and biomechanical study in human cadavers

BACKGROUND

Lengthening of the gastrocnemius-soleus complex is frequently performed for equinus deformity. Many techniques have been described, but there is uncertainty regarding the precise details of some surgical procedures.

METHODS

The surgical anatomy of the gastrocnemius-soleus complex was investigated, and standardized approaches were developed for the procedures described by Baumann, Strayer, Vulpius, Baker, Hoke, and White. The biomechanical characteristics of these six procedures were then compared in three randomized trials involving formaldehyde-preserved human cadaveric lower limbs. After one of the lengthening procedures was performed, a measured dorsiflexion force was applied across the metatarsal heads with use of a torque dynamometer. Lengthening of the gastrocnemius-soleus complex was measured directly, by measuring the gap between the ends of the fascia or tendon.

RESULTS

The gastrocnemius-soleus musculotendinous unit was subdivided into three zones. In Zone 1, it was possible to lengthen the gastrocnemius-soleus complex in either a selective or a differential manner-i.e., to lengthen the gastrocnemius alone or to lengthen the gastrocnemius and soleus by different amounts. The procedures performed in this zone (Baumann and Strayer procedures) were very stable but were limited with regard to the amount of lengthening achieved. Zone-2 lengthenings of the conjoined gastrocnemius aponeurosis and soleus fascia (Vulpius and Baker procedures) were not selective but were stable and resulted in significantly greater lengthening than Zone-1 procedures (p < 0.001). In Zone 3 (Hoke and White procedures), lengthenings of the Achilles tendon were neither selective nor stable but resulted in significantly greater lengthening than Zone-1 or 2 procedures (p < 0.001).

CONCLUSIONS

Surgical procedures for the correction of equinus deformity by lengthening of the gastrocnemius-soleus complex vary in terms of selectivity, stability, and range of correction. Procedures for the correction of equinus deformity have different anatomical and biomechanical characteristics. Clinical trials are needed to determine whether these differences are of clinical importance. It may be appropriate for surgeons to select a procedure involving the zone best suited to the clinical needs of a specific patient.

Induction of polyphosphoinositide breakdown in rat corpus luteum by prostaglandin F2 alpha

The present study examines the possibility that, in the rat corpus luteum, an initial action of prostaglandin F2 alpha (PGF2 alpha) is to induce a ligand-stimulated breakdown of membrane inositol phospholipids. Luteal cells in primary culture were prepared from immature rats after PMSG and human CG priming. In 32P-prelabeled cells, PGF2 alpha caused a rapid decrease in the level of radiolabel found in phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate, as early as 20 sec after addition of the hormones. At 1 and 2.5 min, the effect of 10(-6) M PGF2 alpha on phosphatidylinositol 4,5-bisphosphate was significantly greater than that caused by 10(-6) M LHRH in identical cell cultures. By contrast, the levels of the 32P-prelabeled phosphatidylinositol and phosphatidic acid were increased at 5 min by PGF2 alpha or LHRH. Concomitant with the alterations in cellular levels of 32P-prelabeled phospholipids, PGF2 alpha markedly enhanced the accumulation of 3H-labeled inositol phosphates, i.e. inositol 1-phosphate, inositol diphosphate, and inositol triphosphate, during a 5-min incubation. A significant increase of radiolabeled inositol diphosphate was seen as early as 1 min after the addition of either PGF2 alpha or LHRH; PGF2 alpha was more effective than LHRH in this regard. The stimulatory effect of LHRH on inositol phosphate accumulation could be blocked completely by the concomitant presence of a potent LHRH antagonist, and at the concentration used (10(-6) M) the effects of PGF2 alpha and LHRH were not additive. Interestingly, the addition of an exogenous phospholipase C also caused a similar enhancement of inositol phosphate accumulation in identical cell cultures. For the first time, these data suggest that, at the level of the corpus luteum, hydrolysis of phosphoinositides may immediately follow PGF2 alpha (and to a lesser extent LHRH) receptor binding, and this in turn may lead to the generation of 1,2-diacylglycerol and inositol phosphates, resynthesis of phosphatidic acid and phosphatidylinositol, and mobilization of Ca2+.

Thickness-induced structural phase transformation of layered gallium telluride

We report a spontaneous phase transformation of GaTe, occurring when the bulk is exfoliated to a few layers. The results demonstrate the crucial role of interlayer interactions in the structural stability.

Woven silk fabric-reinforced silk nanofibrous scaffolds for regenerating load-bearing soft tissues

Although three-dimensional (3-D) porous regenerated silk scaffolds with outstanding biocompatibility, biodegradability and low inflammatory reactions have promising application in different tissue regeneration, the mechanical properties of regenerated scaffolds, especially suture retention strength, must be further improved to satisfy the requirements of clinical applications. This study presents woven silk fabric-reinforced silk nanofibrous scaffolds aimed at dermal tissue engineering. To improve the mechanical properties, silk scaffolds prepared by lyophilization were reinforced with degummed woven silk fabrics. The ultimate tensile strength, elongation at break and suture retention strength of the scaffolds were significantly improved, providing suitable mechanical properties strong enough for clinical applications. The stiffness and degradation behaviors were then further regulated by different after-treatment processes, making the scaffolds more suitable for dermal tissue regeneration. The in vitro cell culture results indicated that these scaffolds maintained their excellent biocompatibility after being reinforced with woven silk fabrics. Without sacrifice of porous structure and biocompatibility, the fabric-reinforced scaffolds with better mechanical properties could facilitate future clinical applications of silk as matrices in skin repair.

Effects of annealing ambient on oxygen vacancies and phase transition temperature of VO2 thin films

VO₂ thin films are prepared on Si substrates by direct-current (DC) magnetron sputtering at room temperature and annealed in vacuum at different argon pressures.

Microencapsulated hepatocytes: an in vitro and in vivo study

Using a modified alginate-polylysine membrane, we have successfully encapsulated rat hepatocytes with little loss of viability. Urea and albumin release from encapsulated liver cells was comparable to that from non-encapsulated cells during the first 4 days in culture. Histological studies also showed that more than 50% of the encapsulated hepatocytes remained viable 35 days after implantation in the peritoneal cavity of both normal rats and rats with galactosamine induced fulminant hepatic failure. Transplantation of microencapsulated hepatocytes provides a potential clinical treatment for liver failure.

GABA-A receptor activity in the noradrenergic locus coeruleus drives trigeminal neuropathic pain in the rat; contribution of NAα1 receptors in the medial prefrontal cortex

Trigeminal neuropathic pain is described as constant excruciating facial pain. The study goal was to investigate the role of nucleus locus coeruleus (LC) in a model of chronic orofacial neuropathic pain (CCI-ION). The study examines LC's relationship to both the medullary dorsal horn receiving trigeminal nerve sensory innervation and the medial prefrontal cortex (mPFC). LC is a major source of CNS noradrenaline (NA) and a primary nucleus involved in pain modulation. Although descending inhibition of acute pain by LC is well established, contribution of the LC to facilitation of chronic neuropathic pain is also reported. In the present study, a rat orofacial pain model of trigeminal neuropathy was induced by chronic constrictive injury of the infraorbital nerve (CCI-ION). Orofacial neuropathic pain was indicated by development of whisker pad mechanical hypersensitivity. Hypersensitivity was alleviated by selective elimination of NA neurons, including LC (A6 cell group), with the neurotoxin anti-dopamine-β-hydroxylase saporin (anti-DβH-saporin) microinjected either intracerebroventricularly (i.c.v.) or into trigeminal spinal nucleus caudalis (spVc). The GABA_A receptor antagonist, bicuculline, administered directly into LC (week 8) inhibited hypersensitivity. This indicates a valence shift in which increased GABA_A signaling ongoing in LC after trigeminal nerve injury paradoxically produces excitatory facilitation of the chronic pain state. Microinjection of NAα1 receptor antagonist, benoxathian, into mPFC attenuated whisker pad hypersensitivity, while NAα2 receptor antagonist, idazoxan, was ineffective. Thus, GABA_A-mediated activation of NA neurons during CCI-ION can facilitate hypersensitivity through NAα1 receptors in the mPFC. These data indicate LC is a chronic pain generator.

Trace element levels in drinking water and cognitive function among elderly Chinese

The relation between trace element levels in drinking water and cognitive function was investigated in a population-based study of elderly residents (n = 1,016) in rural China in 1996-1997. Cognitive function was measured using a Chinese translation of the Community Screening Interview for Dementia. A mixed effects model was used to evaluate the effect of each of the elements on cognitive function while adjusting for age, sex, and educational level. Several of the elements examined had a significant effect on cognitive function when they were assessed in a univariate context. However, after adjustment for other elements, many of these results were not significant. There was a significant quadratic effect for calcium and a significant zinc-cadmium interaction. Cognitive function increased with calcium level up to a certain point and then decreased as calcium continued to increase. Zinc showed a positive relation with cognitive function at low cadmium levels but a negative relation at high levels.

Diabetes and hearing impairment in Mexican American adults: a population-based study

Reports on the relationship between diabetes and hearing loss have been controversial. The present study examined this relationship in 1,740 Mexican American adults using data from the Hispanic Health and Nutrition Examination Survey. Hearing threshold levels were obtained for each participant at the following frequencies: 500, 1000, 2000, and 4000 Hertz (Hz). The thresholds from the worse hearing ear were used in the analyses. Diabetes and insulin use were assessed by self-report. The mean crude hearing thresholds in diabetics were significantly higher than in non-diabetics at each of the four frequencies. However, after adjustment for age, gender, and socioeconomic status, diabetics had a significantly higher mean threshold than non-diabetics only at 500 Hz (mean difference +/- SE: 2.8 +/- 1.2, p = 0.04). Diabetics who were not using insulin had significantly higher thresholds than those who were using insulin at 2000 (mean difference +/- SE: 5.6 +/- 2.6, p = 0.03) and 4000 Hz (7.7 +/- 3.3, p = 0.02). Also, at 4000 Hz, insulin users had a significantly lower mean threshold than non-diabetics (mean difference +/- SE: -4.9 +/- 1.6, p = 0.02). Our data suggest that associations between diabetes and decreased hearing acuity in the higher frequencies are present only amongst diabetic Mexican-Americans who do not use insulin.

Pharmacokinetics and bioavailability of midazolam after intravenous, subcutaneous, intraperitoneal and oral administration under a chronic food-limited regimen: relating DRL performance to pharmacokinetics

The effects of midazolam on animal behavior often are evaluated under a chronically food-limited regimen, which is used to implement food-reinforced performance, but the corresponding pharmacokinetics are lacking. The present study investigated the pharmacokinetics of midazolam after i.v., s.c., i.p., and p.o. administration in food-limited rates. A two-compartment model best described the concentration-time profiles for the four routes of administration. The rate of midazolam absorption was rapid, and peak concentrations were attained in less than 7 min for the three extravascular routes. The mean volume of distribution of the central compartment and clearance were 0.77 l/kg and 2.03 l/h per keg, respectively. Midazolam elimination half-lives for the four routes of administration ranged from 23.1 to 49.5 min, and metabolites could not be detected. The mean absolute bioavailability was route-dependent: 39.3% (s.c.) 19.2% (i.p.) and 4.6% (p.o.). The markedly low oral bioavailability found in food-limited rats contrasted to the value reported for free-feeding rates (45%). Although the i.p. route yielded the highest maximum concentration on occasion, serum midazolam concentration-time profiles were variable, but did correspond to respective sedative responses. DRL 45-s performance after s.c., i.p., and p.o. administration further supported the advisability of using the s.c. route of administration, as opposed to the i.p. route, for studying midazolam dose-response relations. The bioavailability values assessed from DRL performance also agree with the measured pharmacokinetic values.

Cocaine pharmacodynamics after intravenous and oral administration in rats: relation to pharmacokinetics

RATIONALE

To design optimal dose regimes for oral cocaine, it is essential to characterize pharmacokinetics (PK) of cocaine after IV and PO administration.

OBJECTIVES

To investigate the absolute bioavailability of oral cocaine, its effectiveness and the relation between PK and PD in a within-subject design.

METHODS

We used the effects of IV and PO cocaine on a contingency-controlled timing behavior, the differential reinforcement of low rate schedule (DRL 45-s) in 3-h sessions, as the PD measures [i.e., the shorter-response rate (srr) and the reinforcement rate (rr)]. Cocaine PK parameters were determined by simultaneous modeling of the concentration-time profiles (CTPs) after IV 2 mg/kg and PO 20 mg/kg cocaine administration. The absolute oral cocaine bioavailability was determined pharmacokinetically (F) and pharmacodynamically (Fsrr and Frr).

RESULTS

IV and PO cocaine increased the shorter response rate and decreased the reinforcement rate in a dose- and time-related fashion, which mirrored the respective prototypical serum cocaine CTPs. After the absorption phase, the serum cocaine CTP of PO cocaine paralleled that of IV cocaine. The duration of action for PO cocaine was longer than that for IV cocaine owing to its larger mean residence time. The active metabolite, norcocaine, was not detected after IV but after PO cocaine administration. The value of F was 4.66% which was significantly lower than the values of Fsrr (13.67%) and Frr (32.63%). Furthermore, the concentration-effect relations for the reinforcement rate revealed that PO cocaine was more potent than IV cocaine.

CONCLUSIONS

Oral cocaine is more effective behaviorally than from predictions made in terms of its PK. The differences in active metabolite profiles as well as the rate and extent of acute tolerance for IV versus PO cocaine may account for the greater potency observed for oral cocaine.

Plasma zinc, copper, copper:zinc ratio, and survival in a cohort of HIV-1-infected homosexual men

A prospective cohort study of 121 HIV-1-positive homosexual men was conducted in Miami, Florida, U.S.A. to evaluate the associations between plasma zinc and copper levels and mortality. Plasma zinc and copper levels were measured at baseline and then at semiannual visits. Zinc inadequacy and copper inadequacy were defined as plasma zinc levels <75 (microg/dl) and plasma copper levels <85 (microg/dl), respectively. HIV-1-related deaths were confirmed by review of death certificates. Cox proportional hazards regression models with time-dependent covariates were used to estimate the relative risks of zinc and copper inadequacy on mortality. Over the average course of the 3.3-year follow-up, 19 participants (16%) died of HIV-1-related causes. After adjustment for potential confounders, including low CD4+ cell counts and antiretroviral therapy, zinc inadequacy and copper:zinc ratio >1 (i.e., plasma copper level greater than plasma zinc level) were associated with increased mortality (relative risks [RRs]; 95% confidence intervals [CIs], 4.98, 1.30-19.00 and 8.28, 1.03-66.58, respectively). A negative association was also observed between plasma zinc levels and mortality (RR 0.94; 95% CI, 0.91-0.98). Plasma levels of copper were not significantly associated with mortality. These results suggest that plasma zinc inadequacy or the plasma copper:zinc ratio may be useful predictors of survival in HIV-1 infection. The latter appears to be a stronger predictor.

Longitudinal Association between Selenium Levels and Hypertension in a Rural Elderly Chinese Cohort

OBJECTIVES

Results from previous studies have been inconsistent on the association between selenium and hypertension, and very few studies on this subject have focused on the elderly population. The purpose of this study is to examine the relationship between selenium level and hypertension in a rural elderly Chinese cohort.

DESIGN

A longitudinal study was implemented and data were analyzed using logistic regression models and Cox proportional hazards regression model adjusting for potential confounders. The associations between selenium level and prevalent hypertension at baseline and between selenium and incident hypertension were examined.

SETTING

Community-based setting in four rural areas in China.

SUBJECTS

A total of 2000 elderly aged 65 years and over (mean 71.9±5.6 years) participated in this study.

MEASUREMENTS

Nail selenium levels were measured in all subjects at baseline. Blood pressure measures and self-reported hypertension history were collected at baseline, 2.5 years and 7 years later. Hypertension was defined as systolic blood pressure 140 mmHg or higher, diastolic blood pressure 90 mmHg or higher, or reported use of anti-hypertensive medication.

RESULTS

The rate of baseline hypertension was 63.50% in this cohort and the mean nail selenium level is 0.413±0.183μg/g. Multi-covariate adjusted cross-sectional analyses indicated that higher selenium level was associated with higher blood pressure measures at baseline and higher rates of hypertension. For the 635 participants with normal blood pressure at baseline, 360 had developed hypertension during follow-up. The incidence rate for hypertension was 45.83%, 52.27%, 62.50%, 70.48%, and 62.79% from the first selenium quintile to the fifth quintile respectively. Comparing to the lowest quintile group, the hazard ratios were 1.41 (95%CI: 1.03 to1.94), 1.93 (95%CI: 1.40 to 2.67), 2.35 (95%CI: 1.69 to 3.26) and 1.94 (95%CI: 1.36 to 22.77) for the second selenium quintile to the fifth quintile respectively.

CONCLUSIONS

Our findings suggest that high selenium may play a harmful role in the development of hypertension. Future studies are needed to confirm our findings and to elucidate a plausible biological mechanism.

Luteinizing hormone-releasing hormone enhances polyphosphoinositide breakdown in rat granulosa cells

A 2-min addition of LHRH to [3H]inositol-prelabeled rat granulosa cells in primary culture evoked significant increases in the accumulation of [3H]inositol phosphates, i.e. radiolabeled inositol monophosphate (IP), inositol diphosphate (IP2), and inositol triphosphate (IP3) levels increased to 210, 590 and 520%, respectively, when compared to control cultures. By contrast, addition of FSH failed to elicit such a response. The effect of LHRH was completely blocked by the concomitant presence of a specific LHRH antagonist. LHRH evoked increase in [3H]IP3 and [3H]IP2 accumulation as early as 30 sec, while the increase in [3H]IP became significant at 2 min. These data support the hypothesis that polyphosphoinositide breakdown may be an early step in the intracellular signal mechanism which mediates the action of LHRH.

Establishment of a GM-CSF-dependent megakaryoblastic cell line with the potential to differentiate into an eosinophilic lineage in response to retinoic acids

We recently established a human granulocyte-macrophage colony-stimulating factor (GM-CSF)-dependent cell line (HML) from colony-constituent cells grown by peripheral blood cells of a patient with acute megakaryoblastic leukaemia. The HML cells possessed megakaryocytic features, as determined by cytochemical, electron microscopic and flow cytometric analysis. In the present study we examined the effects of retinoic acid (RA) on the development of HML cells. All-trans-RA, 13-cis-RA and 9-cis-RA at 10(-8) mol/l to 10(-5) mol/l inhibited the GM-CSF-dependent cell growth. Some of the RA-treated cells contained prominent azurophilic granules and were positive for peroxidase. They also reacted with Biebrich scarlet, Luxol fast blue and a monoclonal antibody against eosinophil peroxidase. In addition, exposure to RA increased the frequency and the intensity of major basic protein-positive cells. However, eosinophil-derived neurotoxin and eosinophil cationic protein were not detected or were only detected at a low level in the lysates of the HML cells treated with RA. Although IL-5 alone could not stimulate cell growth, the addition of IL-5 to the cultures containing stem cell factor + all-trans-RA was required for the expression of the eosinophilic phenotype. These results suggest that the HML cell line is a megakaryoblastic cell line with the potential to differentiate into the eosinophilic lineage. HML cells may be a useful model for elucidating the eosinophilic differentiation programme.

Simultaneous determination of cocaine and its metabolites with caffeine in rat serum microsamples by high-performance liquid chromatography

A single, isocratic high-performance liquid chromatographic method is described for the determination of cocaine and three of its metabolites along with caffeine in serum microsamples (50 microliters). The small sample size permits the tracking of pharmacokinetic data over time in individual, small animals. The method also was used to demonstrate that cocaine, benzoylecgonine and norcocaine in rat serum samples were stable for at least a month without the presence of sodium fluoride.