[Morphological changes of the central sulcus in children with complete growth hormone deficiency: a 3.0 T MRI study]

Objective: To analyze morphological changes in central sulcus of the cerebral cortex in children with complete growth hormone deficiency (CGHD). Methods: Patients attending the Shandong Provincial Hospital who were diagnosed with CGHD or idiopathic short stature were recruited from January 2015 to January 2019. Thirty children with CGHD (18 males and 12 females, 5 to 14 years old) and 30 children with idiopathic short stature (22 males and 8 females, 5 to 14 years old) were included. Measurements of the central sulcus, including the average width, maximum depth, average depth, top length, bottom length and depth position-based profiles (DPP), were obtained using Brain VISA software. The significant differences between groups were statistically analyzed. Results: The average width of bilateral central sulci in children with CGHD (left: (2.26±0.41) mm; right: (2.19±0.34) mm) were significantly higher than those in children with idiopathic short stature (left: (2.10±0.27) mm; right: (2.02±0.18) mm) (P<0.05) ; The maximum depth of the left central sulcus ((19.67±1.29) mm) and the average depth of the right central sulcus ((14.18±1.41) mm) were significantly lower than those in children with idiopathic short stature (left maximum depth: (20.69±1.43) mm; right average depth: (14.92±1.21) mm) (P<0.05) . Children with CGHD had significantly lower DPP at the middle part of the left central sulcus (sites: 46-54) and the inferior part of the right central sulcus(sites: 91-98). Conclusion: There are significant morphological changes of the central sulcus in children with CGHD, which may represent the structural basis of their relatively slower development in motor, cognitive and linguistic functional performance.

Elevated levels of IL-24 in systemic lupus erythematosus patients

OBJECTIVE

This study aimed to assess IL-24 levels and their association with clinical manifestations in patients with systemic lupus erythematosus (SLE).

METHODS

There were 75 patients with SLE and 58 healthy controls recruited in this study. Serum levels of IL-24 were measured by enzyme-linked immunosorbent assays, and mRNA levels of IL-24 were tested by quantitative real-time polymerase chain reaction . The area under the curve of the receiver operating characteristic (ROC) curve was used for diagnostic ability of the inflammatory cytokine.

RESULTS

Serum IL-24 levels were significantly higher in SLE patients than that in healthy controls. SLE patients with nephritis had higher IL-24 levels than those without nephritis. Active SLE patients showed higher expression of IL-24 as compared to less active disease patients. The mRNA levels of IL-24 were much higher in SLE patients. Correlation analysis showed significant correlation between serum IL-24 levels and SLE disease activity index. In addition, ROC analysis may suggest good ability of serum IL-24 in differentiating SLE.

CONCLUSION

The inflammatory cytokine correlated with SLE disease activity, and may be involved in this disease pathogenesis.

Intratumoral IL17-producing cells infiltration correlate with antitumor immune contexture and improved response to adjuvant chemotherapy in gastric cancer

BACKGROUND

Tumor IL17-producing (IL17A+) cells infiltration has different prognostic values among various cancers. The objective of this study was to assess the effect of IL17A+ cells in gastric cancer.

PATIENTS AND METHODS

The study included two patient cohorts, the Cancer Genome Atlas cohort (TCGA, n = 351) and the Zhongshan Hospital cohort (ZSHC, n = 458). The TCGA and ZSHC were used for mRNA-related and cells infiltration-related analyses, respectively. The roles of IL17A mRNA and IL17A+ cells in overall survival (OS), response to adjuvant chemotherapy (ACT), and immune contexture were evaluated. Another independent cohort was included to identify the correlation between mRNA of IL17A and IL17A+ cells infiltration (the preliminary Zhongshan Hospital cohort, PZSHC, n = 21).

RESULTS

The infiltration of IL17A+ cells was positively correlated with the expression of IL17A mRNA (Spearman's ρ = 0.811; P < 0.001). High IL17A mRNA expression and intratumoral IL17A+ cells were correlated with improved OS and remained to be significant after adjusted for confounders. Patients with TNM II/III disease whose tumor present higher intratumoral IL17A+ cells or lower peritumoral IL17A+ cells can benefit more from ACT. Elevated IL17A mRNA expression and increased intratumoral IL17A+ cells infiltration was associated with more antitumor mast cells and nature killer cells infiltration and less pro-tumor M2 macrophages infiltration. High IL17A mRNA expression represented a Th17 cells signature and immune response process and was correlated with increased cytotoxic GZMA, GZMB, IFNG, PRF1, and TNFSF11 expression.

CONCLUSIONS

IL17A mRNA expression and intratumoral IL17A+ cells infiltration were correlated with antitumor immune contexture. IL17A+ cells infiltration could be used as an independent prognostic biomarker for OS and predictive biomarker for superior response to ACT, and further prospective validation needs to be conducted.

[Abuse of diphenoxylate and related factors of forced drug abstainer in Gansu province]

Objective: To investigate the prevalence of diphenoxylate abuse and related factors of forced drug abstainer in Gansu province. Methods: By using a self-designed questionnaire, an epidemiologic investigation was carried out among 2 108 forced drug abstainer selected from the compulsory isolation detoxification center of Gansu province. A case-control study was conducted to analyze the factors related with diphenoxylate abuse. Results: The diphenoxylate abuse rate among forced drug abstainer in Gansu was 19.8% (406/2 046), ranking first in medical drug abuse. Multiple logistic regression analysis showed that factors as relieving withdrawal symptoms (OR=2.08, 95%CI: 1.01- 4.32), ways to obtain diphenoxylate (other ways: OR=1.00; regular clinic: OR=27.67, 95%CI: 2.64-289.82; friend: OR=0.01, 95%CI: 0.01-0.03), degree of euphoria (high: OR=1.00; medium: OR =3.36, 95%CI: 1.18-9.55; low: OR=26.16, 95%CI: 10.30-66.42), years of drug abuse (<5 years: OR=1.00; 10-15 years: OR=2.48, 95%CI: 1.02-6.04), abuse at home or in friend's house (OR=3.04, 95%CI: 1.08-8.68), abuse in car (OR=0.05, 95%CI: 0.00-0.68) and detoxification for the first time (OR=0.61, 95%CI: 0.43-0.86) were the possible influencing factors for diphenoxylate abuse. Conclusions: The prevalence of diphenoxylate abuse in forced drug abstainer in Gansu was relatively high. Reasons of abusing, the way to obtain diphenoxylate, whether using drug together with friends, degree of euphoria, years of abuse, abuse place and times for detoxification were related factors influencing the abuse of diphenoxylate.

[Study on the immunogenicity and safety of recombinant B-subunit/whole cell cholera vaccine infused with antacids in healthy population at ages of 2-6 years]

Objective: To assess the immunogenicity and safety of recombinant B-subunit/whole cell cholera vaccine (rBS/WC) oral cholera vaccine (Ora Vacs) infused with antacids in healthy population at ages of 2-6 years. Methods: Between December 2009 and January 2010, we recruited 900 volunteers aged 2-6 years od through giving out recruitment notice for the eligible children's parents from different vaccination clinics of Chongzuo city in Guangxi Zhuang Autonomous Region. This study was a randomized, double-blind, placebo-controlled trial, and subjects were randomly (2∶1) assigned to receive Cholera vaccine infused with antacids or placebo, and observed for safety. Serum samples of 300 subjects in immunogenicity subgroups (200 for vaccine groups, 100 for control groups) before the 1st dose and 49 d (±3 d) after immunization were collected, and determined for antibody levels against the cholera toxin (anti-CT) and cholera vibriocidal (anti-Vab) with Enzyme-linked immunosorbent assays (ELISA), based on which the GMT was calculated. There were 266 cases paired with the serum samples before and after immunization (177 for vaccine groups, 89 for control groups). The comparison of subjects' age at enrollment and the level of GMT before and after immunization between groups were analyzed by t test. The superiority test for the difference between seroconversion rates of vaccine groups and control groups were analyzed by χ(2) test. Results: Of 900 subjects enrolled, the number of males and females were 503 and 397 respectively (vaccine groups 335 vs. 265, control groups 168 vs. 132), the average ages of vaccine groups and control groups at enrollment were (4.8±1.2) years and (4.9±1.2) years respectively. There were no significant differences between groups in terms of gender and age (χ(2)=0.00, P=1.000; t=0.55, P=0.585). The 2 times increase rates of anti-CT and anti-Vab in vaccine groups after inoculation were 90.96% and 57.63% respectively, which were superiority to those of control groups (15.73% and 29.21%), and significant differences were observed between groups (χ(2)=15.89, χ(2)=3.85, P<0.001). There were significant differences between vaccine groups and control groups after inoculation in terms of GMTs of anti-CT (1∶647.56 vs. 1∶99.49) and anti-Vab antibodies (1∶16.19 vs. 1∶11.27) (t values were 15.82 and 3.43, respetively; both P values were<0.05), significant differences were observed in the growth rates when compared the GMTs of anti-CT (6.63 vs. 1.11) and anti-Vab antibodies (1.64 vs. 1.16) before inoculation between vaccine groups and control groups (t'=17.85 and 4.96, P<0.001). In terms of safety, the adverse reaction rates in vaccine groups and control groups were 37.67% (226/600) and 36.67% (110/300), respectively,the common adverse reaction including fever, nausea, vomiting, abdominal pain, diarrhea, headache, fatigue, allergies, rash, etc; and the severity degree were mainly for level 1. Conclusion: Ora Vacs infused with antacids could produce an positive effect on immune response and safety.

[Prevalence of type-specific human papillomavirus infection among 18-45 year-old women from the general population in Liuzhou, Guangxi Zhuang Autonomous Region: a cross-sectional study]

Objective: To analyze the type-specific prevalence of human papillomavirus (HPV) among women aged 18-45 years from the general population in Liuzhou, Guangxi Zhuang Autonomous Region. Methods: Totally, 2 300 women aged 18-45 years old were enrolled in Liuzhou,from March to July, 2013. Cervical exfoliated cells were collected for liquid based cytological and HPV DNA tests. Women were referred to colposcopy exam, based on the clinical practice guideline. Results: Overall, the prevalence rates of any HPV or oncogenic HPV appeared as 22.7% (95% CI: 21.0%-24.4%) and 17.3% (95% CI: 16.0%-19.1%), respectively in this population under study. The high-risk HPV prevalence peaked at the age groups of 18-25 and 41-45, increasing along with the severity through cytological and histological tests. Statistically significant differences between the prevalence of CIN2+ (Cervical intraepithelial neoplasia 2+) in women older than 26 years (1.7%, 95% CI: 1.0%-2.4%) and 18-25 years (1.2%, 95% CI: 0.5%-1.9%) of age, were not observed. Among samples diagnosed as CIN2+, positivity of HPV bivalent (16/18) and nine-valent (6/11/16/18/31/33/45/52/58) vaccine, related high risks on the types of HPV types appeared as 44.1% and 97.1%. Conclusions: The age-specific HPV prevalence rates in the general women aged 18-45 in Liuzhou presented as having bimodal distribution, suggesting that the disease burden of cervical diseases in women aged 26-45 years should not be ignored. Nine-valent HPV vaccine might provide more effective prevention outcomes on cervical cancer in China.

Chronic sleep fragmentation induces endothelial dysfunction and structural vascular changes in mice

STUDY OBJECTIVES

Sleep fragmentation (SF) is a common occurrence and constitutes a major characteristic of obstructive sleep apnea (OSA). SF has been implicated in multiple OSA-related morbidities, but it is unclear whether SF underlies any of the cardiovascular morbidities of OSA. We hypothesized that long-term SF exposures may lead to endothelial dysfunction and altered vessel wall structure.

METHODS AND RESULTS

Adult male C57BL/6J mice were fed normal chow and exposed to daylight SF or control sleep (CTL) for 20 weeks. Telemetric blood pressure and endothelial function were assessed weekly using a modified laser-Doppler hyperemic test. Atherosclerotic plaques, elastic fiber disruption, lumen area, wall thickness, foam cells, and macrophage recruitment, as well as expression of senescence-associated markers were examined in excised aortas. Increased latencies to reach baseline perfusion levels during the post-occlusive period emerged in SF mice with increased systemic BP values starting at 8 weeks of SF and persisting thereafter. No obvious atherosclerotic plaques emerged, but marked elastic fiber disruption and fiber disorganization were apparent in SF-exposed mice, along with increases in the number of foam cells and macrophages in the aorta wall. Senescence markers showed reduced TERT and cyclin A and increased p16INK4a expression, with higher IL-6 plasma levels in SF-exposed mice.

CONCLUSIONS

Long-term sleep fragmentation induces vascular endothelial dysfunction and mild blood pressure increases. Sleep fragmentation also leads to morphologic vessel changes characterized by elastic fiber disruption and disorganization, increased recruitment of inflammatory cells, and altered expression of senescence markers, thereby supporting a role for sleep fragmentation in the cardiovascular morbidity of OSA.

Psoriasis is associated with decreased plasma adiponectin levels independently of cardiometabolic risk factors

BACKGROUND

Psoriasis is an inflammatory skin disease that may be associated with an adverse cardiometabolic profile including modulated plasma adiponectin and leptin levels. Whether these levels are independent of cardiometabolic risk factors, which are also prevalent in psoriasis, is not known.

METHODS

A consecutive sample of 122 participants with varying degrees of psoriasis severity, and a random sample of 134 participants without psoriasis, were recruited for this case-control study. Cardiometabolic risk factors including traditional cardiovascular risk factors, waist circumference, insulin resistance, and total plasma adiponectin and leptin were measured. Total plasma adiponectin and leptin levels were compared in unadjusted and adjusted analyses by psoriasis status.

RESULTS

Participants with psoriasis had mostly mild disease and were mainly on topical therapies, but still had a more adverse cardiometabolic profile compared with those without psoriasis. Furthermore, plasma adiponectin levels were significantly lower in participants with psoriasis than those without {7.13 μg/mL [interquartile range (IQR) 4.9-11.3) vs. 14.5 μg/mL (IQR 8.4-24.1); P < 0.001]}. Plasma leptin (ng/mL) levels were higher in the psoriasis group but this did not reach statistical significance [11.3 (IQR 6.4-21.8) vs. 9.8 (IQR 4.9-20.5); P = 0.07]. In multivariable modelling, plasma adiponectin levels were still negatively associated with psoriasis status after adjusting for waist size (% difference = -41.2%, P < 0.001), insulin resistance (% difference = -39.5%, P < 0.001), and both waist size and insulin resistance (% difference = -38.5%, P < 0.001).

CONCLUSIONS

Plasma levels of adiponectin were lower in psoriasis, and this relationship persisted after adjusting for cardiometabolic risk factors known to decrease adiponectin levels. These findings suggest that inflammation present in psoriasis may be associated with adipose tissue dysfunction; however, direct studies of adipose tissue are needed to confirm this.

Growth hormone releasing hormone (GHRH) signaling modulates intermittent hypoxia-induced oxidative stress and cognitive deficits in mouse

Intermittent hypoxia (IH) during sleep, such as occurs in obstructive sleep apnea (OSA), leads to degenerative changes in the hippocampus, and is associated with spatial learning deficits in adult mice. In both patients and murine models of OSA, the disease is associated with suppression of growth hormone (GH) secretion, which is actively involved in the growth, development, and function of the central nervous system (CNS). Recent work showed that exogenous GH therapy attenuated neurocognitive deficits elicited by IH during sleep in rats. Here, we show that administration of the Growth Hormone Releasing Hormone (GHRH) agonist JI-34 attenuates IH-induced neurocognitive deficits, anxiety, and depression in mice along with reduction in oxidative stress markers such as MDA and 8-hydroxydeoxyguanosine, and increases in hypoxia inducible factor-1α DNA binding and up-regulation of insulin growth factor-1 and erythropoietin expression. In contrast, treatment with a GHRH antagonist (MIA-602) during intermittent hypoxia did not affect any of the IH-induced deleterious effects in mice. Thus, exogenous GHRH administered as the formulation of a GHRH agonist may provide a viable therapeutic intervention to protect IH-vulnerable brain regions from OSA-associated neurocognitive dysfunction. Sleep apnea, characterized by chronic intermittent hypoxia (IH), is associated with substantial cognitive and behavioral deficits. Here, we show that administration of a GHRH agonist (JI-34) reduces oxidative stress, increases both HIF-1α nuclear binding and downstream expression of IGF1 and erythropoietin (EPO) in hippocampus and cortex, and markedly attenuates water maze performance deficits in mice exposed to intermittent hypoxia during sleep.

Serum Levels of Calcitonin Gene-Related Peptide and Substance P are Decreased in Patients with Diabetes Mellitus and Coronary Artery Disease

OBJECTIVE: This study evaluated serum levels of the neuropeptides calcitonin gene-related peptide (CGRP) and substance P (SP) in coronary artery disease (CAD) patients with and without a history of diabetes mellitus (DM). METHODS: Patients undergoing coronary angiography for suspected myocardial ischaemia were divided into four groups depending on their clinical status: control group (no CAD or DM; n = 44), DM group (DM without CAD; n = 46), CAD group (stable CAD without DM; n = 44) and DM + CAD group (stable CAD with DM; n = 50). Serum levels of CGRP and SP were determined using radioimmunoassays. RESULTS: CGRP and SP levels in the DM and CAD groups were significantly lower than in the control group. The lowest levels of CGRP and SP were observed in the DM + CAD group. There were no significant differences in CGRP and SP levels between the DM group and the CAD group. CONCLUSION: CGRP and SP may have a role in the pathogenesis of CAD in patients with diabetes.

Exogenous growth hormone attenuates cognitive deficits induced by intermittent hypoxia in rats

Sleep disordered breathing (SDB), which is characterized by intermittent hypoxia (IH) during sleep, causes substantial cardiovascular and neurocognitive complications and has become a growing public health problem. SDB is associated with suppression of growth hormone (GH) secretion, the latter being integrally involved in the growth, development, and function of the CNS. Since GH treatment is able to attenuate neurocognitive deficits in a hypoxic-ischemic stroke model, GH, GH receptor (GHR) mRNA expression, and GH protein expression were assessed in rat hippocampus after exposures to chronic sustained hypoxia (CH, 10% O(2)) or IH (10% O(2) alternating with 21% O(2) every 90 s). In addition, the effect of GH treatment (50 μg/kg daily s.c. injection) on erythropoietin (EPO), vascular endothelial growth factor (VEGF), heme oxygenase-1 (HO-1), and GLUT-1 mRNA expression and neurobehavioral function was assessed. CH significantly increased GH mRNA and protein expression, as well as insulin-like growth factor-1 (IGF-1). In contrast, IH only induced a moderate increase in GH mRNA and a slight elevation in GH protein at day 1, but no increases in IGF-1. CH, but not IH, up-regulated GHR mRNA in the hippocampus. IH induced marked neurocognitive deficits compared with CH or room air (RA). Furthermore, exogenous GH administration increased hippocampal mRNA expression of IGF-1, EPO, and VEGF, and not only reduced IH-induced hippocampal injury, but also attenuated IH-induced cognitive deficits. Thus, exogenous GH may provide a viable therapeutic intervention to protect IH-vulnerable brain regions from SDB-associated neuronal loss and associated neurocognitive dysfunction.

An inter-subspecies cloned buffalo (Bubalus bubalis) obtained by transferring of cryopreserved embryos via somatic cell nuclear transfer

The aim of this study was to explore the feasibility of cryopreservation of inter-subspecies cloned embryos in buffalo. In our experiment, river buffalo ear fibroblast nucleus was fused into swamp buffalo oocyte cytoplasm. The blastocyst formation rate for nuclear transfer of freshly thawed cells was not different from those of growing cells, confluent or serum-starved cells. A total of 122 cloned blastocysts derived from cryopreserved fibroblasts were cryopreserved and thawed, 37 were survived, the cryosurvival rate was 30.3%. The survived blastocysts were transferred into 15 recipient buffalos. Five of the recipients established pregnancy, but four of them aborted on day 53, 59, 145 and 179 of gestation respectively. One cross-bred buffalo (Murrah × Swamp buffalo (2n = 49) received three embryos delivered a 40.5 kg female calf by natural delivery on day 320 of gestation. Up to now (13-month old), the cloned calf has been growing well with no abnormity observed. These results demonstrated that cryopreservation of inter-subspecies cloned embryos is feasible to produce buffalo offspring.

Leukotriene B4 receptor-1 mediates intermittent hypoxia-induced atherogenesis

RATIONALE

Obstructive sleep apnea, which is characterized by intermittent hypoxia (IH) during sleep, has emerged as an independent risk factor for cardiovascular disease, including atherosclerosis. Leukotriene B4 (LTB4) production is increased in patients with obstructive sleep apnea and negatively correlates to hypoxic levels during sleep, with continuous positive airway pressure therapy decreasing LTB4 production.

OBJECTIVES

Determine the potential role of LTB4 in IH-induced atherosclerosis in a monocyte cellular model and a murine model.

METHODS

THP-1 cells were exposed to IH for 3, 6, 24, and 48 hours. Macrophage transformation and foam cell formation were assessed after IH exposures. Apolipopotein E (ApoE)(-/-) or BLT1(-/-)/ApoE(-/-) mice were fed an atherogenic diet and exposed to IH (alternating 21% and 5.7% O(2) from 7 am to 7 PM each day) for 10 weeks. Atherosclerotic lesion formation in en face aorta was examined by oil red O staining.

MEASUREMENTS AND MAIN RESULTS

IH increased production of LTB4 and the expression of 5-lipoxygenase and leukotriene A4 hydrolase, the key enzymes for producing LTB4. IH was associated with transformation of monocytes to activated macrophages, as evidenced by increased expression of CD14 and CD68. In addition, IH exposures promoted increased cellular cholesterol accumulation and foam cell formation. The LTB4 receptor 1 (BLT1) antagonist U-75302 markedly attenuated IH-induced changes. Furthermore, IH promoted atherosclerotic lesion formation in ApoE(-/-) mice. IH-induced lesion formation was markedly attenuated in BLT1(-/-)/ApoE(-/-) mice.

CONCLUSIONS

BLT1-dependent pathways underlie IH-induced atherogenesis, and may become a potential novel therapeutic target for obstructive sleep apnea-associated cardiovascular disease.

Study on the inter-subspecies nuclear transfer of river buffalo somatic cell nuclei into swamp buffalo oocyte cytoplasm

The objective of this study was to explore the feasibility of inter-subspecies somatic cell nuclear transfer (SCNT) of river buffalo (50 chromosomes) somatic cell nuclei into swamp buffalo (48 chromosomes) oocyte cytoplasm. The enucleated swamp buffalo oocytes were fused with four different types of river buffalo cells: freshly thawed ear fibroblasts, serum-starved ear fibroblasts, cumulus cells and ear fibroblasts from a cloned buffalo calf. As a result, the developmental competence of embryos reconstructed with freshly thawed ear fibroblasts was the poorest (P<0.01), while those of the other three types were not different from each other. Furthermore, the efficiency of swamp-swamp buffalo, swamp-river buffalo and bovine-buffalo SCNT were also compared. The results showed that the blastocyst rate of swamp-river reconstructed embryos was not different from swamp-swamp embryos, while significantly higher than that of bovine-buffalo embryos (P<0.01). A total of thirty cloned blastocysts derived from freshly thawed ear fibroblasts were transferred into thirteen recipient buffaloes, four recipients established pregnancy, while three of them aborted on Days 65, 75 and 90 of gestation, respectively. One cross-bred buffalo (Murrah x swamp, 49 chromosomes) receiving three embryos delivered a 39 kg female calf on Day 335 of gestation. These results indicate that the inter-subspecies SCNT is feasible to produce swamp-river buffalo embryos, and these can develop to full term and result in live buffalo calves.

Increased cellular proliferation and inflammatory cytokines in tonsils derived from children with obstructive sleep apnea

Adenotonsillar hypertrophy is the major pathophysiological mechanism underlying obstructive sleep apnea (OSA) and recurrent tonsillitis (RI) in children. The increased expression of various mediators of the inflammatory response in tonsils of patients with OSA prompted our hypothesis that the enhanced local and systemic inflammation in children with OSA would promote tonsillar proliferation. Mixed cell cultures from tonsils recovered during adenotonsillectomy in children with OSA and RI were established, and proliferative rates were assessed. Cells were also cultured to determine the levels of proinflammatory cytokines and antioxidant protein levels and mRNA expression. Global cell proliferative rates from OSA tonsils were significantly higher than RI (p < 0.01), with CD3, CD4, and CD8 cell proliferation being higher in OSA (p < 0.05). Moreover, proinflammatory cytokines, such as TNF-alpha, IL-6, and IL-1alpha, were highly expressed in OSA-derived tonsils. Furthermore, thioredoxin (TRX), an antioxidant protein, was also highly expressed in OSA tonsils at the mRNA and protein levels (p < 0.01). Thus, T cells are in a highly proliferative state in the tonsils of children with OSA and are associated with increased production of proinflammatory cytokines and TRX, when compared with children with RI.

Green tea catechin polyphenols attenuate behavioral and oxidative responses to intermittent hypoxia

RATIONALE

The intermittent hypoxia (IH) that characterizes sleep-disordered breathing impairs spatial learning and increases NADPH oxidase activity and oxidative stress in rodents. We hypothesized that green tea catechin polyphenols (GTPs) may attenuate IH-induced neurobehavioral deficits by reducing IH-induced NADPH oxidase expression, lipid peroxidation, and inflammation.

OBJECTIVES

To assess the effects of GTP administered in drinking water on the cognitive, inflammatory, and oxidative responses to long-term (>14 d) IH during sleep in male Sprague-Dawley rats.

METHODS

Cognitive assessments were conducted in the Morris water maze. We measured levels and expression of malondialdehyde (MDA), prostaglandin E(2), p47(phox) subunit of NADPH oxidase, receptor for advanced glycation end products (RAGE), and glial fibrillary acidic protein expression in rodent brain tissue.

MEASUREMENTS AND MAIN RESULTS

GTP treatment prevented IH-induced decreases in spatial bias for the hidden platform during the Morris water maze probe trails as well as IH-induced increases in p47phox expression within the hippocampal CA1 region. In untreated animals, IH exposure was associated with doubling of cortical MDA levels in comparison to room air control animals, and GTP-treated animals exposed to IH showed a 40% reduction in MDA levels. Increases in brain RAGE and glial fibrillary acidic protein expression were observed in IH-exposed animals, and these increases were attenuated in animals treated with GTP.

CONCLUSIONS

Oral GTP attenuates IH-induced spatial learning deficits and mitigates IH-induced oxidative stress through multiple beneficial effects on oxidant pathways. Because oxidative processes underlie neurocognitive deficits associated with IH, the potential therapeutic role of GTP in sleep-disordered breathing deserves further exploration.

Neuroglobin protects PC12 cells against oxidative stress

Neuroglobin (Ngb) is a newly discovered globin in the vertebrate brain that exhibits neuroprotection against hypoxic/ischemic injury. Hypoxic/ischemic brain injury is associated with accumulation of reactive oxygen species (ROS) and/or reactive nitrogen species (RNS), and antioxidants or ROS scavengers promote cell survival. Therefore, Ngb may serve as a scavenger of toxic reactive species, such as hydrogen peroxide. To examine the anti-oxidative role of neuroglobin, PC12 cells were transfected with wild type and mutant (H64 V/H96A) Ngb for 48 h and then treated with H2O2 (0.1, 0.2 and 0.4 mM) for 6 h. Ngb siRNA decreased the H2O2-induced Ngb expression and exacerbated H2O2-induced cell injury. Transient transfection of Ngb induced dose-dependent increases in Ngb protein expression and did not alter SOD, GPX, and catalase activities. Overexpression of wild type Ngb, but not of mutant Ngb, significantly attenuated H2O2-induced ROS/RNS accumulation and lipid peroxidation, decreased H2O2-induced mitochondrial dysfunction and apoptosis, and promoted overall cell survival. Thus, Ngb plays a protective role against oxidative stress, which appears to be primarily mediated by intrinsic Ngb antioxidant properties.

Neuroglobin protects PC12 cells against beta-amyloid-induced cell injury

Excessive accumulation of amyloid beta (Abeta) has been proposed as a pivotal event in the pathogenesis of Alzheimer's disease. Possible mechanisms underlying Abeta-induced neuronal cytotoxicity include excess production of reactive oxidative species (ROS) and apoptosis. Neuroglobin (Ngb), a newly discovered globin in vertebrates that exhibits neuroprotective functions, may have a potential role in scavenging ROS. To examine the potential protective role of Ngb in Abeta-induced cytotoxicity, PC12 cells were treated with Abeta (1-42 fragment) for 24h. Abeta treatments increased ROS production in PC12 cells. Overexpression of Ngb but not Ngb mutant in the PC12 cells significantly attenuated Abeta-induced ROS production and lipids peroxidation. Furthermore, overexpression of Ngb also attenuated Abeta-induced mitochondrial dysfunction and apoptosis, and promoted cell survival in PC12 cells. Therefore, Ngb may act as an intracellular ROS scavenger, and such antioxidant properties may play a protective role against Abeta-induced cell injury.

Inflammatory Mediators in Exhaled Breath Condensate of Children With Obstructive Sleep Apnea Syndrome

BACKGROUND

Upper airway inflammation is now recognized in adults with obstructive sleep apnea (OSA) syndrome. However, the role played by eicosanoids such as leukotrienes and prostaglandins is unclear.

OBJECTIVE

To investigate whether eicosanoids are measurable in exhaled breath condensate (EBC), and to determine whether differences in these inflammatory mediators emerge among children with and without sleep-disordered breathing (SDB).

METHODS

EBC was collected from 50 consecutive snoring children undergoing overnight polysomnography for suspected SDB, and from 12 nonsnoring control subjects. Prostaglandin E2 (PGE2), leukotriene B4 (LTB4), and cysteinyl leukotrienes (cys-LTs: leukotriene C4 [LTC4]/leukotriene D4 [LTD4]/leukotriene E4 [LTE4]) EBC levels were analyzed using enzyme-linked immunosorbent assay.

RESULTS

LTB4 levels were elevated in children with an apnea-hypopnea index (AHI) > 5/h (SDB; 97.6 +/- 6.3 pg/mL) compared to children with an AHI < 5/h (mild SDB; 66.4 +/- 19.1 pg/mL; p < 0.01) and control subjects (27.8 +/- 3.7 pg/mL; p < 0.01). Similarly, cys-LT (LTC4/LTD4/LTE4) concentrations were also increased in SDB (45.1 +/- 10.6 pg/mL in SDB vs 27.6 +/- 8.3 pg/mL in mild SDB, and 15.7 +/- 7.6 pg/mL in control subjects; p < 0.01). In contrast, PGE2 concentrations were similar among the three groups.

CONCLUSIONS

Inflammatory mediators such as leukotrienes and prostaglandins can be readily quantified in EBC collected from the upper airway of children. Disease severity-dependent increases in leukotriene concentrations (LTB4 and LTC4/LTD4/LTE4) emerge among children and may serve as a noninvasive tool in the clinical assessment of these children.

Hypoxia differentially regulates the expression of neuroglobin and cytoglobin in rat brain

Neuroglobin (Ngb) and Cytoglobin (Cygb) are new members of the globin family and display heterotopic expression patterns. To examine the effect of different hypoxia profiles on expression of Ngb and Cygb in rodent brain, rats were exposed to either sustained hypoxia (SH; 10% O(2)) or intermittent hypoxia (IH; 10% and 21% O(2) alternating every 90 s) for 1, 3, 7 and 14 days, and mRNA and protein expression of Ngb and Cygb were assessed in brain cortex. SH increased Ngb mRNA and protein expression throughout the exposure, while IH only elicited slight increases in Ngb expression at day 1. Neither SH nor IH elicited increases in Cygb expression. Thus, hypoxic stimulus presentation is a major determinant of the regulation of hypoxic sensitive genes such as Ngb. Furthermore, disparities between Ngb and Cygb responses to hypoxia further suggest that these two globins may play divergent roles in brain.

Apolipoprotein E-Deficient Mice Exhibit Increased Vulnerability to Intermittent Hypoxia-Induced Spatial Learning Deficits

Exposure to intermittent hypoxia, such as occurs in sleep-disordered breathing, is associated with oxidative stress, cognitive impairments, and increased neuronal apoptosis in brain regions involved in learning and memory. Apolipoprotein E (ApoE) has been implicated in neurodegenerative disorders, and in vitro studies suggest that one of the functions of ApoE may be to confer protection from oxidant stress-induced neuronal cell loss. Therefore, we hypothesized that ApoE-deficient (ApoE-/-) mice would display increased cognitive impairments following intermittent hypoxia. Twenty-four young adult male mice (ApoE-/-) and 24 wild-type littermates (ApoE +/+) were exposed to 14 days of normoxia (room air; n=12 per group) or intermittent hypoxia (5.7% O2 alternating with 21% O2 every 90 seconds, 12 daylight hours per day; n=12 per group). Behavioral testing consisting of a standard place-training reference memory task in the water maze revealed that ApoE+/+ and ApoE-/- mice exposed to intermittent hypoxia were found to require significantly longer times (latency) and distances (pathlength) to locate the hidden platform (P < .005), compared to mice exposed to room air. However, only intermittent hypoxia-exposed ApoE-/- mice were impaired on the final two days of training (P < .03), as well as on measures of spatial bias conducted 24 hours after completion of training (P < .02). Furthermore, increased prostaglandin E2 and malondiadehyde concentrations were present in hippocampal brain tissues following intermittent hypoxia but were significantly higher in ApoE-/- mice (P < .01). Thus, decreased ApoE function is associated with increased susceptibility to neurocognitive dysfunction in a rodent model of sleep-disordered breathing and may underlie the increased prevalence of Apolipoprotein E4 in patients with sleep-disordered breathing.

Tyrosine hydroxylase expression and activity in the rat brain: differential regulation after long-term intermittent or sustained hypoxia

Tyrosine hydroxylase, a hypoxia-regulated gene, may be involved in tissue adaptation to hypoxia. Intermittent hypoxia, a characteristic feature of sleep apnea, leads to significant memory deficits, as well as to cortex and hippocampal apoptosis that are absent after sustained hypoxia. To examine the hypothesis that sustained and intermittent hypoxia induce different catecholaminergic responses, changes in tyrosine hydroxylase mRNA, protein expression, and activity were compared in various brain regions of male rats exposed for 6 h, 1 day, 3 days, and 7 days to sustained hypoxia (10% O2), intermittent hypoxia (alternating room air and 10% O2), or normoxia. Tyrosine hydroxylase activity, measured at 7 days, increased in the cortex as follows: sustained > intermittent > normoxia. Furthermore, activity decreased in the brain stem and was unchanged in other brain regions of sustained hypoxia-exposed rats, as well as in all regions from animals exposed to intermittent hypoxia, suggesting stimulus-specific and heterotopic catecholamine regulation. In the cortex, tyrosine hydroxylase mRNA expression was increased, whereas protein expression remained unchanged. In addition, significant differences in the time course of cortical Ser40tyrosine hydroxylase phosphorylation were present in the cortex, suggesting that intermittent and sustained hypoxia-induced enzymatic activity differences are related to different phosphorylation patterns. We conclude that long-term hypoxia induces site-specific changes in tyrosine hydroxylase activity and that intermittent hypoxia elicits reduced tyrosine hydroxylase recruitment and phosphorylation compared with sustained hypoxia. Such changes may not only account for differences in enzyme activity but also suggest that, with differential regional brain susceptibility to hypoxia, recruitment of different mechanisms in response to hypoxia will elicit region-specific modulation of catecholamine response.

Protein binding and antimicrobial activity of ceftriaxone: comparative assessments by gradient plate technique and time-kill study

In conjunction with initial bactericidal rate measurements, this study evaluated the impact of protein binding on the antimicrobial activity of ceftriaxone employing the gradient plate technique. Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923 were employed as test organisms. At various albumin concentrations (0 to < or = 16% w/v), the effects of albumin binding were estimated by the shift in concentration-responses (via initial bactericidal rate) and the distance of inhibition zone (DIZ) on gradient agar plates. Supplementation with 4% albumin reduced the antimicrobial activity of ceftriaxone against E. coli as suggested by the similar 1.5-fold shift in both initial bactericidal rate and DIZ when compared to those with no albumin. As with S. aureus, the inclusion of albumin increased the initial bactericidal rate but the DIZ assessments showed a reduction in antimicrobial activity. The reason for the difference observed on the initial bactericidal effect between the two species is unknown. However, the similar patterns of change in the DIZ data at increasing albumin concentrations from 0 to 4% for both organisms suggest consistency and reproducibility of the gradient plate technique. This technique appears to be an attractive alternative for the assessment of the effect of protein binding on antibiotics.

Glucocorticoid receptor subunit expression in adenotonsillar tissue of children with obstructive sleep apnea

Tonsillectomy and adenoidectomy (T&A) is a frequent surgical procedure in children with obstructive sleep apnea (OSA). Many symptomatic children who do not fulfill the currently recommended criteria for T&A may benefit from topical intranasal steroid therapy. However, the expression of glucocorticoid receptor (GCR) expression in adenoid and tonsillar tissue is currently unknown. The objective of this study was to assess and compare expression patterns of the human GCR in children who undergo T&A for either recurrent throat infections (RI) or OSA. Adenotonsillar tissues from 36 children with OSA or RI were subjected to quantitative PCR using specific primers for GCR-alpha and GCR-beta and to immunohistochemistry and Western blotting for protein expression of GCR isoforms. mRNA encoding for expression of both GCR-alpha and GCR-beta was detected in the tonsils and adenoids of all children, with markedly higher relative abundance of the GCR-alpha. Furthermore, GCR-alpha mRNA expression was increased in OSA-derived adenoid and tonsil tissues compared with RI, whereas no differences emerged for GCR-beta. Immunoblots confirmed these findings for the protein transcripts of these genes, and immunohistochemistry showed a specific topographic pattern of distribution for both receptors in tonsillar tissue. GCR-alpha and GCR-beta are expressed in pediatric adenotonsillar tissue, are more abundant in OSA patients, and demonstrate a specific topographic pattern of expression. These findings along with the high GCR-alpha:GCR-beta ratio suggest a favorable profile for topical steroid therapy in snoring children with adenotonsillar hypertrophy.

Nitric oxide synthase and intermittent hypoxia-induced spatial learning deficits in the rat

Intermittent hypoxia (IH) during sleep induces significant neurobehavioral deficits in the rat. Since nitric oxide (NO) has been implicated in ischemia-reperfusion-related pathophysiological consequences, the temporal effects of IH (alternating 21% and 10% O(2) every 90 s) and sustained hypoxia (SH; 10% O(2)) during sleep for up to 14 days on the induction of nitric oxide synthase (NOS) isoforms in the brain were examined in the cortex of Sprague-Dawley rats. No significant changes of endothelial NOS (eNOS) and neuronal NOS (nNOS) occurred over time with either IH or SH. Similarly, inducible NOS (iNOS) was not affected by SH. However, increased expression and activity of iNOS were observed on days 1 and 3 of IH (P < 0.01 vs. control; n = 12/group) and were followed by a return to basal levels on days 7 and 14. Furthermore, IH-mediated neurobehavioral deficits in the water maze were significantly attenuated in iNOS knockout mice. We conclude that IH is associated with a time-dependent induction of iNOS and that the increased expression of iNOS may play a critical role in the early pathophysiological events leading to IH-mediated neurobehavioral deficits.

Differential expression of cysteinyl leukotriene receptors 1 and 2 in tonsils of children with obstructive sleep apnea syndrome or recurrent infection

BACKGROUND

Recurrent tonsillitis and sleep apnea are the major indications for tonsillectomy in children. We hypothesized that the recurrent vibration in the upper airway of snoring children would promote inflammatory changes in the tonsillar tissue and would lead to the up-regulation of cysteinyl leukotriene (LT) receptors (Rs).

OBJECTIVE

To assess the expression patterns of the human LT-Rs in children undergoing tonsillectomy, and compare those patterns in children having recurrent throat infections (RIs) and children with obstructive sleep apnea syndrome (SA).

METHODS

Tonsillar tissue from 17 children with SA and 13 with RIs was subjected to quantitative polymerase chain reaction using specific primers for LT1-R and LT2-R, and to immunohistochemistry and Western blotting for protein expression of LT1-R and LT2-R.

RESULTS

Messenger RNA encoding for the expression of LT1-R and LT2-R was detected in the tonsils of all children. Immunoblots revealed significantly higher expressions of LT1-R and LT2-R in the tonsils of children with SA. The topographic pattern of both receptors differed among the tonsils of children with SA and RI.

CONCLUSION

LT1-R and LT2-R are expressed in pediatric tonsillar tissue, are more abundant in SA patients, and demonstrate a specific topographic pattern of expression. These findings suggest that an inflammatory process involving LT expression and regulation occurs in children with SA.

Platelet-activating factor receptor-deficient mice are protected from experimental sleep apnea-induced learning deficits

Intermittent hypoxia (IH) during sleep, a hallmark of sleep apnea, is associated with neurobehavioral impairments, regional neurodegeneration and increased oxidative stress and inflammation in rodents. Platelet-activating factor (PAF) is an important mediator of both normal neural plasticity and brain injury. We report that mice deficient in the cell surface receptor for PAF (PAFR-/-), a bioactive mediator of oxidative stress and inflammation, are protected from the spatial reference learning deficits associated with IH. Furthermore, PAFR-/- exhibit attenuated elevations in inflammatory signaling (cyclo-oxygenase-2 and inducible nitric oxide synthase activities), degradation of the ubiquitin-proteasome pathway and apoptosis observed in wild-type littermates (PAFR+/+) exposed to IH. Collectively, these findings indicate that inflammatory signaling and neurobehavioral impairments induced by IH are mediated through PAF receptors.

Using hydrophilic adhesive tape for collection of evidence for forensic DNA analysis

Known exemplar samples of human DNA have traditionally been body fluids, such as blood, saliva, and semen. In each case, the presence of water is a risk for the bacterial growth, which may degrade the DNA evidence. In this study, the authors have developed a method that employed a hydrophilic adhesive tape (HAT) for collecting DNA evidence. The HAT method was used to remove surface cells from relatively hairless areas on the body. The area examined were ankle, arm, behind the ear, between fingers and back of the neck. The HAT was then dissolved in the extraction buffer. DNA typing was performed at vWA, THo1, F13A1, and FES loci using the short tandem repeat (STR) analysis. Our results show that the samples collected from ear give the best results with a success rate of 100%. All subjects tested by this method had known STR genotypes established from buccal swabs. The authors' results suggest that the HAT method can be used as a less invasive method for collecting biological evidence for forensic DNA analysis. In addition, this collection method should reduce the risk of DNA degradation due to the moisture, which is encountered using conventional collecting methods.

Cyclooxygenase 2 and intermittent hypoxia-induced spatial deficits in the rat

Intermittent hypoxia (IH) during sleep, a critical feature of sleep apnea, induces significant neurobehavioral deficits in the rat. Cyclooxygenase (COX)-2 is induced during stressful conditions such as cerebral ischemia and could play an important role in IH-induced learning deficits. We therefore examined COX-1 and COX-2 genes and COX-2 protein expression and activity (prostaglandin E2 [PGE2] tissue concentration) in cortical regions of rat brain after exposure to either IH (10% O2 alternating with 21% O2 every 90 seconds) or sustained hypoxia (10% O2). In addition, the effect of selective COX-2 inhibition with NS-398 on IH-induced neurobehavioral deficits was assessed. IH was associated with increased COX-2 protein and gene expression from Day 1 to Day 14 of exposure. No changes were found in COX-1 gene expression after exposure to hypoxia. IH-induced COX-2 upregulation was associated with increased PGE2 tissue levels, neuronal apoptosis, and neurobehavioral deficits. Administration of NS-398 abolished IH-induced apoptosis and PGE2 increases without modifying COX-2 mRNA expression. Furthermore, NS-398 treatment attenuated IH-induced deficits in the acquisition and retention of a spatial task in the water maze. We conclude that IH induces upregulation and activation of COX-2 in rat cortex and that COX-2 may play a role in IH-mediated neurobehavioral deficits.

The integration of four major determinants of antibiotic action: bactericidal activity, postantibiotic effect, susceptibility, and pharmacokinetics

A functional pharmacokinetic/pharmacodynamic (PK/PD) index that could simultaneously describe three controlling PD variables, i.e., bactericidal activity, postantibiotic effect (PAE), and susceptibility, in relation to pharmacokinetics, was designed using an in vitro kinetic model. Tobramycin was tested against one standard and five clinical strains of Pseudomonas aeruginosa. The organisms showed minimum inhibitory concentrations (MICs) ranging between 1 and >1000 microg/ml. The model allowed antibiotic concentrations to be reduced exponentially from initial concentrations at fixed multiples of MIC. Antibiotic removal was performed when the decreasing concentrations hit the MIC of individual strain to provide a wide range of AUC(>MIC) within an identical frame of AUC(>MIC)/MIC (AUIC) values. Viable counts were measured at antibiotic addition and before/after its removal for bactericidal activity and PAE assessments. A linear relationship was observed between PAE and bactericidal rate constants, though the pattern varied among different strains. Characterization of the exposure (AUC(>MIC))-effect relationships using the Emax model revealed that the less susceptible strains displayed lower Emax and higher EC50 for both antimicrobial effects. By employing the AUIC as a common frame of reference, regression analysis showed a significant linear correlation (p < 0.05) between the mean PAE and bactericidal rate data and, thereby simultaneously defining the four contributing factors of the PK/PD system. It appears that the AUIC, by conveying the pharmacokinetic and susceptibility information, could serve as a PK/PD index in bridging the interdependency of PAE and bactericidal activity. More importantly, the collective assessment of these four factors would allow more optimal evaluation of dosage regimens.

The monoplace hyperbaric chamber and management of decompression illness

Three cases of decompression illness are reported. Two patients presented with joint pain and skin signs, while one patient presented with joint pain and neurological signs and symptoms. The patients received emergency recompression therapy in a Hong Kong clinic, using a monoplace hyperbaric chamber. All three patients were treated successfully and no residual signs or symptoms were evident on review at 90 days' post-treatment. Issues concerning the use of monoplace and multiplace hyperbaric chambers are also discussed, along with additional clinical applications of the monoplace hyperbaric chamber.

Efficacy and mechanisms of action of rmB7.2-Ig as an antitumor agent in combination with Adriamycin and Cytoxan chemotherapy

The efficacy of chemotherapy for cancer is often limited by toxicity. Immune approaches to cancer immunotherapy, while promising for specificity and long-term protection, have not typically proven potent enough to generate significant therapeutic responses. We have shown therapeutic benefit using recombinant murine B7.2-Ig (rmB7.2-Ig) in murine tumor models. Efficacy was dependent on immune activity and was not associated with toxicity. Recently, the efficacy of rmB7.2-Ig was demonstrated in leukemia tumor models in combination with chemotherapeutic agents. To further explore the potential of this approach, we evaluated the efficacy in solid tumor models of rmB7.2-Ig given in combination with chemotherapeutics commonly used in clinical practice, testing the effects of dose and schedule. RmB7.2-Ig in combination with some chemotherapeutics enhances the activity and efficacy of reduced chemotherapeutic doses. However, the relative timing of chemotherapy and rmB7.2-Ig dosing can be important. Investigation of mechanisms of action based on histological studies suggests that inflammatory as well as T cell mechanisms comprise the response. Additional studies of mice deleted of B7.1, B7.2, and CTLA-4 suggest that the enhanced response induced by rmB7.2-Ig may not be mediated through CD28 ligation alone. The efficacy suggests potential for recombinant human B7.2-Ig as an adjuvant to chemotherapy in promoting immune-mediated mechanisms to augment the activity of chemotherapy.

Induction of hepatic and presystemic metabolism of antipyrine in the mice: rifampicin versus rifabutin

The effects of hepatic and presystemic enzyme induction on the bioavailability (F) and disposition of antipyrine after repeated rifampicin (RFM) and rifabutin (RBT) exposure were studied in mice. ICR mice were divided to receive 4 daily oral dosing of either the dosing vehicle or 50 mg/kg of REM or RBT. At the completion of rifamycin dosing, the pharmacokinetics of antipyrine were assessed following either a single 50 mg/kg oral dose or a 20 mg/kg intravenous dose. Blood samples were collected (n=4/timepoint) over a 6 h period. The content of P450 in the liver and small intestine (GI) was also assessed in parallel. Systemic antipyrine clearance (CL) increased from 31.8 ml/min/kg (controls) by 64% and 42% following repeated exposure to RFM and RBT, respectively. Estimate of F for antipyrine decreased from 0.97 in controls to 0.58 and 0.82 in animals treated with RFM and RBT, respectively. The content of P450 (nmol/mg protein) in the liver increased from 0.61 (control) to 1.36 following RFM and 0.82 for RBT, while no significant changes were observed for the GI tract. The i.v. dosing data confirmed the induction of antipyrine metabolism in the liver by both rifamycins yet the induction potential was approximately 1/3 lower for RBT. This difference was consistent with the changes observed in the hepatic P450 protein content, but this alone could not account for the reduction in the F for antipyrine. Therefore, predictions for changes in F of an interacting agent should not be judged solely on the basis of the metabolic status of the liver. The relative contribution of metabolic induction and presystemic drug loss to bioavailability/absorption should also be further delineated for its relevance to poly-pharmacy in patients likely to receive long-term rifamycin based treatment.

Effects of repeated rifabutin administration on the pharmacokinetics of intravenous and oral ciprofloxacin in mice

The combination of rifabutin and ciprofloxacin is potentially useful for the treatment of disseminated Mycobacterium avium-intracellulare (MAC) diseases in HIV-infected patients. Rifabutin is a metabolic enzyme inducer structurally similar to its predecessor, rifampin. Using a mouse model, the effects of repeated exposure of rifabutin on the pharmacokinetics of ciprofloxacin after intravenous (i.v.) and oral (p.o.) dosing were investigated in the present study. Results showed that repeated exposure of rifabutin, relative to control, caused a 16% increase in the plasma clearance (CL) of ciprofloxacin after i.v. dosing (4.19 vs. 4.87 L/h/kg). Estimates of elimination half-life (T1/2) were not affected by rifabutin (control: 0.81 vs. rifabutin pretreated: 1.18 h). The data obtained after oral dosing showed that repeated rifabutin dosing caused a significant reduction in the maximal plasma concentration (Cmax: 1.34 vs. 0.91 microg/mL) and a longer time to Cmax (Tmax: 0.17 vs. 0.33 h). These changes might be in part attributable to the increase in oral clearance (CL/F) by 18%. With or without rifabutin pretreatment, the T1/2 estimates of ciprofloxacin for p.o. dosing were similar (2.37-2.58 h) and were approximately twice as long as those obtained after i.v. dosing. Since the changes in systemic exposure as a result of rifabutin pretreatment were similar after i.v. and p.o. dosing, the oral bioavailability (F) of ciprofloxacin remained unaffected by rifabutin at approximately 38%. The effects of rifabutin on the pharmacokinetics of ciprofloxacin appear to be moderate in the mouse model which might be attributable to the absorption and distribution behavior of the quinolone antibiotic. The therapeutic implications of this interaction, if any, remain to be defined.

[Prevalence of mutants in the determinant region of hepatitis B surface antigen among Chinese carriers after receiving only active postexposure immunoprophylaxis]

OBJECTIVE

To determine the frequency of hepatitis B surface antigen (HBsAg) mutations in the alpha determinant region among children who developed chronic hepatitis B virus (HBV) infection after receiving only active postexposure immunoprophylaxis.

METHODS

HBsAg mutations were determined by PCR-directed nucleotide sequencing and sequence-specific solid-phase PCR analysis(SS-SPPCR) for 97 Chinese carrier cases after hepatitis B vaccination, for 88 children born aged women controls, and for 95 population based children controls.

RESULTS

Prevalence of amino acid substitutions as detected by direct sequencing among carrier cases, women controls, and children controls were 30.9%, 10.2%, and 5.3%, respectively. The most frequent amino acid substitutions observed were at residues 145, 126, and 133. However, there was no difference in the prevalence of 145 and 126 amino acid mutants as detected by a sensitive SS-SPPCR method between carrier cases and controls. The prevalence of 145 Arg and 145 Ala mutants that were detected by SS-SPPCR was 39.2%, 33.0% and 32.6% among carrier cases, women controls, and children controls, respectively. The total odds ratio was 5.41 for mutants detected by direct sequencing. Odds ratio were 34.55 and 33.39 among adw2 subtype and genotype B subjects for mutants detected by direct sequencing, respectively.

CONCLUSIONS

The results show that hepatitis B virus mutants in the determinant are fairly consistent observed but without immune selective pressures; HBV variant strains may pre-existent as minor quasispecies. The prevalence of mutants is related to HBV subtypes and genotypes.

PKCepsilon activation induces dichotomous cardiac phenotypes and modulates PKCepsilon-RACK interactions and RACK expression

Receptors for activated C kinase (RACKs) have been shown to facilitate activation of protein kinase C (PKC). However, it is unknown whether PKC activation modulates RACK protein expression and PKC-RACK interactions. This issue was studied in two PKCepsilon transgenic lines exhibiting dichotomous cardiac phenotypes: one exhibits increased resistance to myocardial ischemia (cardioprotected phenotype) induced by a modest increase in PKCepsilon activity (228 +/- 23% of control), whereas the other exhibits cardiac hypertrophy and failure (hypertrophied phenotype) induced by a marked increase in PKCepsilon activity (452 +/- 28% of control). Our data demonstrate that activation of PKC modulates the expression of RACK isotypes and PKC-RACK interactions in a PKCepsilon activity- and dosage-dependent fashion. We found that, in mice displaying the cardioprotected phenotype, activation of PKCepsilon enhanced RACK2 expression (178 +/- 13% of control) and particulate PKCepsilon-RACK2 protein-protein interactions (178 +/- 18% of control). In contrast, in mice displaying the hypertrophied phenotype, there was not only an increase in RACK2 expression (330 +/- 33% of control) and particulate PKCepsilon-RACK2 interactions (154 +/- 14% of control) but also in RACK1 protein expression (174 +/- 10% of control). Most notably, PKCepsilon-RACK1 interactions were identified in this line. With the use of transgenic mice expressing a dominant negative PKCepsilon, we found that the changes in RACK expression as well as the attending cardiac phenotypes were dependent on PKCepsilon activity. Our observations demonstrate that RACK expression is dynamically regulated by PKCepsilon and suggest that differential patterns of PKCepsilon-RACK interactions may be important determinants of PKCepsilon-dependent cardiac phenotypes.

Pharmacokinetics and system linearity of tea catechins in rat

1. The pharmacokinetics and dose proportionality of three tea catechins were assessed. 2. Male Sprague-Dawley rats (210-230 g) received intravenous (i.v.) doses (50, 100, 200 and 300 mg kg(-1)) of a decaffeinated tea fraction containing (-)-epicatechin (EC: 5%), (-)-epigallocatechin gallate (EGCG: 50%) and (-)-epicatechin gallate (ECG: 13%). 3. Catechins in plasma, urine and faeces were quantitated by HPLC. 4. A two-compartment model was utilized to describe the bi-exponential disposition exhibited by the three catechins. 5. Over this dose range, the central distribution volume (Vc) for these catechins increased significantly (p < 0.05) from 0.17-0.34 to 0.42-0.66 l kg(-1). 6. A concentration-dependent increase in the plasma free fraction of catechins that mirrored the increases in Vc was observed. 7. The estimates of steady-state volume of distribution (Vss) were between 0.68 and 2.08 l kg(-1) at the lowest dose, and tended to increase with dose. 8. Appreciable amount of catechins partitioned into red blood cells (range 9-43%) and was apparently independent of concentration. 9. The mean elimination half-life (t(1/2,beta)) for EC, EGCG and ECG across doses were 43, 124, and 222 min respectively, and were invariant with dose. 10. Parallel to Vc, a 2-3-fold dose-dependent increase (p < 0.05) in systemic clearance (CL) was observed for the three catechins. 11. Urinary recovery was highest (21-31%) for EC, while those for EGCG and ECG was only approximately 3-5%. 12. Faecal recoveries of the catechins were between 0.5 and 5%. 13. In conclusion, the pharmacokinetics of the catechins appeared to be non-linear; dose-dependent changes in xenobiotic distribution might contribute to this observation.

PKCepsilon modulates NF-kappaB and AP-1 via mitogen-activated protein kinases in adult rabbit cardiomyocytes

We have previously shown that protein kinase C (PKC)-epsilon, nuclear factor (NF)-kappaB, and mitogen-activated protein kinases (MAPKs) are essential signaling elements in ischemic preconditioning. In the present study, we examined whether activation of PKCepsilon affects the activation of NF-kappaB in cardiac myocytes and whether MAPKs are mediators of this signaling event. Activation of PKCepsilon (+108% above control) in adult rabbit cardiomyocytes to a degree that has been previously shown to protect myocytes against hypoxic injury increased the DNA-binding activity of NF-kappaB (+164%) and activator protein (AP)-1 (+127%) but not that of Elk-1. Activation of PKCeta did not have an effect on these transcription factors. Activation of PKCepsilon also enhanced the phosphorylation activities of the p44/p42 MAPKs and the p54/p46 c-Jun NH(2)-terminal kinases (JNKs). PKCepsilon-induced activation of NF-kappaB and AP-1 was completely abolished by inhibition of the p44/p42 MAPK pathway with PD98059 and by inhibition of the p54/p46 JNK pathway with a dominant negative mutant of MAPK kinase-4, indicating that both signaling pathways are necessary. Taken together, these data identify NF-kappaB and AP-1 as downstream targets of PKCepsilon, thereby establishing a molecular link between activation of PKCepsilon and activation of NF-kappaB and AP-1 in cardiomyocytes. The results further demonstrate that both the p44/p42 MAPK and the p54/p46 JNK signaling pathways are essential mediators of this event.

Pharmacokinetic and pharmacodynamic interactions between intravenous ciprofloxacin and oral ferrous sulfate

Changes in oral bioavailability and in vitro antimicrobial activity have been the focus of many previous interaction studies for metal cations and quinolones. This study is the first to examine the possibility of an interaction in the systemic circulation using ciprofloxacin and ferrous sulfate as representative interactants in a rat model, and to determine the changes, if any, in the pharmacokinetics and pharmacodynamics of the antibiotic. To minimize direct physical interaction in the gastrointestinal (GI) tract, the current study design required the male Sprague Dawley rats (220-240 g) to be dosed with 100 mg/kg of oral ferrous sulfate and 5 mg/kg of intravenous ciprofloxacin. Control animals received only intravenous ciprofloxacin. Blood and urine samples were collected over time for quantitation of ciprofloxacin independently by both HPLC (H) and microbiological (M) assays. Results showed that the disposition of ciprofloxacin in control animals was biexponential with a mean (+/-SD) terminal elimination half-life (t(1/2,lambda z)) of 0.93+/-0.30 h. A large apparent volume of distribution (V(d,lambda z): 6.96+/-1.56 L/kg) was observed. In addition, concentration vs. time profiles generated by both assays were similar. When the antibiotic was dosed with oral iron, parameter estimates generated by HPLC appeared to show a wider distribution and a longer elimination of ciprofloxacin; mean V(d,lambda z) and t(1/2,lambda z) estimates increased by 2- and 4-fold, respectively. Relative to controls, antibiotic exposure (AUC(0-infinity) was also significantly higher (p<0.05) in the presence of iron (1.89+/-0.15 vs. 1.00+/-0.39 mg/h/L). A strong assay dependency was observed for ciprofloxacin concentrations observed post-distribution; the respective M/H ratios for AUC(0-infinity) and urinary recovery were 1.1 and 0.9 for controls and 0.7 and 0.5 for animals receiving oral iron. This iron related reduction in antimicrobial activity was in clear contrast to the higher exposure and longer t(1/2,lambda z) of the antibiotic. In conclusion, concomitant oral iron dosing induced significant changes in the pharmacokinetics/pharmacodynamics of intravenous ciprofloxacin.

Improvement of phase I drug metabolism with Schisandra chinensis against CCl4 hepatotoxicity in a rat model

The seed extract of Schisandra chinensis was investigated in the rat for its restorative or therapeutic effect on Phase I hepatic drug metabolism following intoxication by carbon tetrachloride (CCl4). Male Sprague Dawley rats (220-250 g) were divided into two sets, one included rats with or without CCl4 intoxication, the other included CCl4 intoxicated rats with or without treatment of Schisandra extract. With the treatment regimen, rats received four oral doses of Schisandra (160 mg/kg) or the same volume of water at 8, 24, 32 and 48 h after CCl4 intoxication. A single oral dose (80 mg/kg) of antipyrine, a conventional probe for oxidative drug metabolism, was then administered. The levels of liver serum transaminases and cytochrome P450 were measured and the pharmacokinetics of antipyrine were assessed using a non-compartmental approach via WinNonlin. In comparison to the rats without CCl4 intoxication (t1/2: 2.2 +/- 0.9 h; Cl/F: 0.30 +/- 0.01 L/h/Kg; P450: 0.611 +/- 0.190 nmol/mg protein), CCl4 administration significantly decreased elimination (t1/2: 12.0 +/- 3.9 h) and oral clearance (Cl/F: 0.049 +/- 0.018 L/h/kg) of antipyrine, and markedly reduced the content of P450 (0.075 +/- 0.011 nmol/mg protein). Data obtained from intoxicated animals treated by Schisandra extract, compared to those without treatment, showed significant (p < 0.05) improvement in the t1/2 (4.45 +/- 1.7 h) and Cl/F (0.096 +/- 0.018 ml/h) estimates of antipyrine and a 2-3 fold increase in P450 level (0.190 +/- 0.072 nmol/mg protein). Findings in this study suggest that the seed extract of Schisandra appeared to be a promising agent for the improvement of Phase I oxidative metabolism in the liver damaged by CCl4.

Oral absorption and bioavailability of tea catechins

The absorption characteristics and oral bioavailability of three tea catechins, namely (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), and (-)-epigallocatechin gallate (EGCG), were assessed in this study. Male Sprague Dawley rats (210-230 g) received either an intravenous (i.v. 50 mg/kg) or oral (5000 mg/kg) dose of decaffeinated catechin-fraction containing EC (5%), EGCG (50%), and ECG (13%). Concentrations of the compounds in plasma, urine, and feces were measured using HPLC. A non-compartmental approach was employed for pharmacokinetic analysis. Results indicated that maximum plasma concentrations for the catechins (15-112 micrograms/ml) were achieved at 2 h post-oral dosing and the apparent volume of distribution (Vd/F) ranged from 30 to 63 l/kg. Absolute bioavailability (F) of EC, EGCG, and ECG was assessed to be 0.39, 0.14, and 0.06, respectively. Estimates of terminal elimination half-life (t1/2, lambda z) of the catechins after oral dosing were 451-479 min and were 1.4-10 fold longer than those observed for the i.v. dosing. The discrepancy in terminal elimination and low rate and extent of absorption indicated the possibility of flip-flop kinetics. Respective urinary recoveries were 0.17-4.72% and 2.11-14.2% after oral and i.v. dosing. In conclusion, the low systemic availability of tea catechins observed could be a result of slow absorption, high first pass effect, and wide tissue distribution.

New pharmacodynamic parameters for antimicrobial agents

The application of pharmacodynamic theories to antimicrobial chemotherapy has greatly improved the prediction of the time course of activity expressed by antibiotics. Being a major component of the antibiotic-bacterium interaction system, pharmacodynamics, when properly integrated with the pharmacokinetics established for the antibiotic, allow better evaluation of the dosage regimen in conjunction with its clinical response. Before this approach becomes effective, detailed background information on the complex antibiotic-bacterium interactions have to be secured. To achieve this, proper characterization of a time-kill curve is a prerequisite. The use of susceptibility endpoints such as the MIC with respect to the antibiotic concentrations achievable in vivo represent the conventional approach to clinical dosing of antimicrobial agents, i.e. by maintaining concentrations above the MIC. Recently, a number of surrogate markers have been proposed by combining suitable pharmacokinetic parameters and susceptibility data, e.g. peak/MIC ratio, AUC>MIC, time above MIC, AUIC etc. to enhance the prediction of clinical outcomes. Attempts have been made to apply these pharmacokinetic/pharmacodynamic markers to antibiotics of the same class as well as to antibiotics from different classes. This review aims to discuss the various microbial dynamic responses in relation to antibiotic exposure and the development of different pharmacokinetic/pharmacodynamic markers for use in current antimicrobial chemotherapy.

Lanthanides enhance pulmonary absorption of insulin

In an effort to investigate the enhancement effect of lanthanide ions (Ln3+) on the absorption of larger molecules from the pulmonary pathway, insulin (mol. wt. = 5730) was chosen as a model peptide. The absorption of insulin preadministered or coadministered with Ln3+ from the lung was investigated by means of an in situ pulmonary absorption experiment. The enhancement absorption of insulin by Ln3+ ions was evaluated by calculating the various bioavailabilities (Fr) of insulin from pulmonary absorption. Moreover, the temporal change of Gd content in serum was also investigated. Results showed that the promoting effect of Ln3+ on the bioavailability of insulin is closely related to its species, concentration, and delivery order. The effect of the median Ln3+ series was remarkably greater than that of light and heavy Ln3+. The anionic form of Gadolinium (Fr = 68.4%) seemed to be more effective compared with its cationic form (Fr = 59.5%). Coadministration of Gd3+ with insulin (Fr = 80.1%) was the most effective in increasing insulin absorption from the lung. Gd3+ was rapidly absorbed and metabolized to a normal level after 4 h. It was suggested that lanthanides in a very low concentration might become potent absorption enhancers to improve absorption of larger molecules via the pulmonary pathway.

Effect of oral administration of fennel (Foeniculum vulgare) on ciprofloxacin absorption and disposition in the rat

The aim of this study was to investigate the possibility of a drug-drug interaction between ciprofloxacin and fennel (Foeniculum vulgare) in a rat model. Pharmacokinetic assessment of ciprofloxacin was performed in two groups of male Sprague-Dawley rats. One group (n = 5) received 20 mg kg(-1) antibiotic orally with concomitant oral dosing of the aqueous fennel extract (2 g herb kg(-1)) whereas the controls (n = 5) received 20 mg kg(-1) oral ciprofloxacin. Blood and urine samples were collected over 6 and 24 h, respectively, for quantitation of ciprofloxacin by HPLC. A non-compartmental model was employed for pharmacokinetic analysis. Major ingredients and metal cations in the fennel extract were determined. Compared with the control, maximum plasma concentration, area under the curve and urinary recovery of ciprofloxacin were significantly (P < 0.05) lower, by 83, 48 and 43%, respectively, in rats receiving concomitant dosing of the two agents. The relative bioavailability of ciprofloxacin, under the influence of fennel, was estimated to be 0.52. In addition, its apparent volume of distribution and terminal elimination half-life were significantly (P < 0.05) increased, from 30.8 +/- 11.1 (L kg(-1)) and 2.0 +/- 0.4 (h) to 143.8 +/- 31.6 (L kg(-1)) and 5.2 +/- 2.0 (h), respectively. Although none of the organic components of fennel seemed to cause this interaction, the total amount of ten metal cations measured was found to be 13 mg g(-1). Significant interaction between ciprofloxacin and fennel was observed in this study. Absorption, distribution and elimination of ciprofloxacin were all affected. These changes might be because of the formation of a more lipophilic ciprofloxacin chelate in the presence of relatively large amounts of metal cations. If, therefore, the two therapeutic agents are used concurrently, an adequate dosing interval is needed to ensure the efficacy of ciprofloxacin.

PKC-dependent activation of p46/p54 JNKs during ischemic preconditioning in conscious rabbits

A conscious rabbit model was used to study the effect of ischemic preconditioning (PC) on stress-activated kinases [c-Jun NH(2)-terminal kinases (JNKs) and p38 mitogen-activated protein kinase (MAPK)] in an environment free of surgical trauma and attending external stress. Ischemic PC (6 cycles of 4-min ischemia/4-min reperfusion) induced significant activation of protein kinase C (PKC)-epsilon in the particulate fraction, which was associated with activation of p46 JNK in the nuclear fraction and p54 JNK in the cytosolic fraction; all of these changes were completely abolised by the PKC inhibitor chelerythrine. Selective enhancement of PKC-epsilon activity in adult rabbit cardiac myocytes resulted in enhanced activity of p46/p54 JNKs, providing direct in vitro evidence that PKC-epsilon is coupled to both kinases. Studies in rabbits showed that the activation of p46 JNK occurred during ischemia, whereas that of p54 JNK occurred after reperfusion. A single 4-min period of ischemia induced a robust activation of the p38 MAPK cascade, which, however, was attenuated after 5 min of reperfusion and disappeared after six cycles of 4-min ischemia/reperfusion. Overexpression of PKC-epsilon in cardiac myocytes failed to increase the p38 MAPK activity. These results demonstrate that ischemic PC activates p46 and p54 JNKs via a PKC-epsilon-dependent signaling pathway and that there are important differences between p46 and p54 JNKs with respect to the subcellular compartment (cytosolic vs. nuclear) and the mechanism (ischemia vs. reperfusion) of their activation after ischemic PC.

Evaluation of the protective effects of Schisandra chinensis on Phase I drug metabolism using a CCl4 intoxication model

To evaluate the potential activity of Schisandra chinensis in restoring hepatic drug metabolism in CCl4 damaged liver, antipyrine was employed as a probe for the possible effects of the herb on Phase I oxidative metabolism in rats. Schisandra lignan fraction (160 mg/kg) was given orally to male Sprague-Dawley rats (220-240 g) 30 min or 6 h before CCl4 intoxication (4 ml/kg, s.c.). Following a single oral dose of antipyrine (80 mg/kg) to the rats with damaged liver, the pharmacokinetics of antipyrine in whole blood were determined and levels of liver enzymes, e.g. SGPT, SGOT, and cytochrome P450 were measured. Pharmacokinetic parameters for antipyrine were estimated using noncompartmental analysis. Results indicated that CCl4 significantly increased the elimination half-life (t(1/2)) of antipyrine from 2.59 +/- 1.04 to 11.25 +/- 3.91 h (P < 0.001) and decreased its clearance (CL) from 65.94 to 10.84 ml/h as compared to control. Pretreatment with the Schisandra lignan fraction 30 min or 6 h before intoxication significantly (P < 0.001) improved antipyrine elimination by reducing its t(1/2) to 3.30 +/- 0.52 and 3.58 +/- 1.05 h, respectively. The corresponding improvements observed for CL, i.e. 49.06 +/- 21.75 ml/h (P < 0.01); 21.10 +/- 10.42 ml/h (P < 0.05), were also substantial. Moreover, normalization of SGPT, SGOT and P450 levels was observed with the two Schisandra pretreatment schedules. In conclusion, Schisandra lignans exhibited strong protective effect on Phase I oxidative metabolism in the liver damaged by CCl4. Furthermore, pretreatment of Schisandra 30 min before intoxication showed a more pronounced effect than that of the 6 h pretreatment. The current pharmacokinetic approach allowed the protective effects of Schisandra on oxidative drug metabolism in damaged liver to be systemically examined and will certainly help in the evaluation of hepato-protectants obtained from natural sources.

Demonstration of selective protein kinase C-dependent activation of Src and Lck tyrosine kinases during ischemic preconditioning in conscious rabbits

Src tyrosine kinases have been shown to mediate cellular responses to stress in noncardiac cells. However, the effect of myocardial ischemia on Src tyrosine kinases is unknown. Furthermore, the identity of the tyrosine kinase(s) involved in the genesis of ischemic preconditioning (PC) remains obscure. Here, we present the first evidence that ischemic PC (6 cycles of 4-minute coronary occlusion and 4-minute reperfusion) induces selective activation of 2 members of the Src family of tyrosine kinases, Src and Lck, in the heart of conscious rabbits. The activation of Src in the particulate fraction was not evident at 5 minutes after ischemic PC but became apparent at 30 minutes (+119% versus control), whereas the activation of Lck in the particulate fraction was apparent both at 5 minutes (+103% versus control) and at 30 minutes (+89%) after ischemic PC. The activity of the other 5 members of the Src tyrosine kinases expressed in the rabbit heart (Fyn, Fgr, Yes, Lyn, and Blk) was not affected by ischemic PC. Ischemic PC had no effect on the activity of epidermal growth factor receptor kinases, either at 5 or at 30 minutes. The activation of Src and Lck was completely abrogated by the tyrosine kinase inhibitor lavendustin A, given at doses that have previously been shown to block the protective effect of ischemic PC in this same conscious rabbit model, suggesting that Src and Lck kinases are essential for the development of ischemic PC. The activity of the epsilon isoform of protein kinase C (PKC) in the particulate fraction increased at 5 minutes (+72%) and at 30 minutes (+67%) after ischemic PC. Pretreatment with lavendustin A had no effect on the activation of PKCepsilon, whereas pretreatment with the PKC inhibitor chelerythrine (given at doses that have previously been shown to block ischemic PC) blocked not only the activation of PKCepsilon but also that of Src and Lck, indicating that Src and Lck are downstream of PKCepsilon in the signaling cascade of ischemic PC. This study identifies a new component of the signaling mechanism of ischemic PC. The results support the concept that, in conscious rabbits, 2 specific members of the Src family of tyrosine kinases, Src and Lck, play an important role in the genesis of late PC by serving as downstream elements of PKC-mediated signal transduction.