Timing of appearance of late oligodendrocyte progenitors coincides with enhanced susceptibility of preterm rabbit cerebral white matter to hypoxia-ischemia

Emerging evidence supports that premature infants are susceptible to both cerebral white and gray matter injury. In a fetal rabbit model of placental insufficiency, preterm rabbits at embryonic day 22 (E22) exhibited histologic evidence of gray matter injury but minimal white matter injury after global hypoxia-ischemia (H-I). We hypothesized that the dissociation between susceptibility to gray and white matter injury at E22 was related to the timing of appearance of late oligodendrocyte progenitors (preOLs) that are particularly vulnerable in preterm human white matter lesions. During normal rabbit oligodendrocyte (OL) lineage progression, early OL progenitors predominated at E22. PreOL density increased between E24 and E25 in major forebrain white matter tracts. After H-I at E22 and E25, we observed a similar magnitude of cerebral H-I, assessed by cortical microvascular blood flow, and gray matter injury, assessed by caspase activation. However, the increased preOL density at E25 was accompanied by a significant increase in acute white matter injury after H-I that coincided with enhanced preOL degeneration. At E29, significant white matter atrophy developed after H-I at E25 but not E22. Thus, the timing of appearance of preOLs coincided with onset of a developmental window of enhanced white but not gray matter susceptibility to H-I.

A phase I study of the nitroimidazole hypoxia marker SR4554 using 19F magnetic resonance spectroscopy

Background:

SR4554 is a fluorine-containing 2-nitroimidazole, designed as a hypoxia marker detectable with ¹⁹F magnetic resonance spectroscopy (MRS). In an initial phase I study of SR4554, nausea/vomiting was found to be dose-limiting, and 1400 mg m⁻² was established as MTD. Preliminary MRS studies demonstrated some evidence of ¹⁹F retention in tumour. In this study we investigated higher doses of SR4554 and intratumoral localisation of the ¹⁹F MRS signal.

Methods:

Patients had tumours ⩾3 cm in diameter and ⩽4 cm deep. Measurements were performed using ¹H/¹⁹F surface coils and localised ¹⁹F MRS acquisition. SR4554 was administered at 1400 mg m⁻², with subsequent increase to 2600 mg m⁻² using prophylactic metoclopramide. Spectra were obtained immediately post infusion (MRS no. 1), at 16 h (MRS no. 2) and 20 h (MRS no. 3), based on the SR4554 half-life of 3.5 h determined from a previous study. ¹⁹Fluorine retention index (%) was defined as (MRS no. 2/MRS no. 1)*100.

Results:

A total of 26 patients enrolled at: 1400 (n=16), 1800 (n=1), 2200 (n=1) and 2600 mg m⁻² (n=8). SR4554 was well tolerated and toxicities were all ⩽grade 1; mean plasma elimination half-life was 3.7±0.9 h. SR4554 signal was seen on both unlocalised and localised MRS no. 1 in all patients. Localised ¹⁹F signals were detected at MRS no. 2 in 5 out of 9 patients and 4 out of 5 patients at MRS no. 3. The mean retention index in tumour was 13.6 (range 0.6–43.7) compared with 4.1 (range 0.6–7.3) for plasma samples taken at the same times (P=0.001) suggesting ¹⁹F retention in tumour and, therefore, the presence of hypoxia.

Conclusion:

We have demonstrated the feasibility of using ¹⁹F MRS with SR4554 as a potential method of detecting hypoxia. Certain patients showed evidence of ¹⁹F retention in tumour, supporting further development of this technique for detection of tumour hypoxia.

Acute scaphoid fracture: a review

The scaphoid is by far the most commonly fractured carpal bone. Occult fractures, imperceptible on initial radiographs and a reputation for non-union make diagnosis and management challenging. The past few years have seen significant advances in the assessment and surgical treatment of scaphoid fractures. This article reviews the published literature relating to acute scaphoid fractures and examines the advances that have been made in management.

Production and characterization of biosurfactants produced by microorganisms isolated from milk factory wastewaters

Biosurfactants or surface-active compounds are produced by microorganisms. These molecules reduce the surface tension of both aqueous solutions and hydrocarbon mixtures. In this study, the isolation and identification of biosurfactant-producing microorganisms were assessed. The characterization of biosurfactant produced by microorganisms isolated from milk factory wastewaters was investigated. For this purpose, five different microorganisms were isolated and identified. In order to determine the biosurfactant production, the 'drop-collapse' method was applied and it was determined that only three species, Yarrowia lipolytica MFW5 (yeast), Micrococcus luteus MFW1 (cocci) and Burkholderia cepacia MFW2 (bacillus), were able to produce biosurfactant. Biosurfactants produced by Yarrowia lipolytica, Micrococcus luteus and Burkholderia cepacia were coded as BS-I, BS-II and BS-III, respectively. After the initial biosurfactant production and characterization studies were completed, isolates of these three species were incubated with whey wastewaters at 35 degrees C for 10 days for biosurfactant production. At the end of the incubation period, the biosurfactants were extracted and further characterized with biochemical analysis, FTIR spectra, haemolysis test, emulsification test and determination of the surface tension.

Tetrahydrobiopterin in the prevention of hypertonia in hypoxic fetal brain

OBJECTIVE

Tetrahydrobiopterin (BH(4)) deficiency is a cause of dystonia at birth. We hypothesized that BH(4) is a developmental factor determining vulnerability of the immature fetal brain to hypoxic-ischemic injury and subsequent motor deficits in newborns.

METHODS

Pregnant rabbits were subjected to 40-minute uterine ischemia, and fetal brains were investigated for global and focal changes in BH(4). Newborn kits were assessed by neurobehavioral tests following vehicle and sepiapterin (BH(4) analog) treatment of dams.

RESULTS

Naive fetal brains at 70% gestation (E22) were severely deficient for BH(4) compared with maternal and other fetal tissues. BH(4) concentration rapidly increased normally in the perinatal period, with the highest concentrations found in the thalamus compared with basal ganglia, frontal, occipital, hippocampus, and parietal cortex. Global sustained 40-minute hypoxia-ischemia depleted BH(4) in E22 thalamus and to a lesser extent in basal ganglia, but not in the frontal, occipital, and parietal regions. Maternal supplementation prior to hypoxia-ischemia with sepiapterin increased BH(4) in all brain regions and especially in the thalamus, but did not increase the intermediary metabolite, 7,8-BH(2). Sepiapterin treatment also reduced incidence of severe motor deficits and perinatal death following E22 hypoxia-ischemia.

INTERPRETATION

We conclude that early developmental BH(4) deficiency plays a critical role in hypoxic-ischemic brain injury. Increasing brain BH(4) via maternal supplementation may be an effective strategy in preventing motor deficits from antenatal hypoxia-ischemia.

Greater osteoporosis educational outreach is desirable among Chinese immigrants in Chinatown, Chicago

Osteoporosis beliefs were assessed in immigrant Chinese women in Chinatown, Chicago. Results from a survey utilizing the Osteoporosis Health Belief Scale showed that women expressed concern about osteoporosis but lacked both knowledge of preventive care and health motivation.

INTRODUCTION

The objective of this study was to assess osteoporosis beliefs in immigrant Chinese women in Chinatown, Chicago.

METHODS

In a community-based health fair, osteoporosis knowledge and self-efficacy among postmenopausal Chinese immigrants were assessed using the translated Osteoporosis Health Belief Scale. Bone mineral density (BMD) was assessed with calcaneal ultrasound.

RESULTS

The study population included 94 women with mean age of 51 +/- 9 years, mean length of residence in the United States of 9 +/- 7 years, and 73% (n = 76) of whom were recent immigrants. Women expressed concern about the seriousness of osteoporosis and their relative susceptibility to osteoporosis. In particular, women with a prior fracture reported higher seriousness to osteoporosis. Nonetheless, women exhibited low health motivation and low awareness of the benefits of calcium and exercise. Bone densitometry results corresponded to a T score of -1.2 +/- 1.5. Multiple regression analysis revealed that a younger age and longer length of residence in the USA were associated with higher BMD.

CONCLUSION

Chinese immigrant women in Chicago exhibit concern regarding osteoporosis, but are unaware of the benefits of calcium and exercise, and exhibit low health motivation. Chinese women in Chinatown lack necessary knowledge about osteoporosis to develop adequate self-efficacy. Public health initiatives should be undertaken among recent immigrant Chinese women.

Selective Enrichment of Hepatocellular Cancer Stem Cells by Chemotherapy

This study investigated the enrichment of cancer stem cells (CSCs) in hepatocellular carcinoma (HCC) by chemotherapy. SMMC-7721 cells were inoculated into mice treated with 0, 2, 5 or 10 mg/kg cyclophosphamide (CTX). Tissue from the resulting tumours was re-inoculated into CTX-treated mice two more times, thus producing three generations of tumour cells for each dose of CTX. Chromosome and fluorescence-activated cell sorting analyses were performed to determine the purity of the enriched cells. Sphere culture, colony formation and proliferation assays demonstrated that the self-renewal potential, proliferative activity and clonogenicity of the enriched cells in vitro increased with increasing chemotherapy dose and generation. The ability of the enriched cells to produce xenograft tumours in mice was also dependent on chemotherapy dose and generation. In conclusion, subjecting HCC cells to chemotherapy in vivo enriched the samples for HCC CSCs in a dose-and generation-dependent manner.

Hypoxia-ischemia causes persistent movement deficits in a perinatal rabbit model of cerebral palsy: assessed by a new swim test

The relationship of movement between different muscle groups has not been quantified before in the newborn period. Cerebral palsy (CP), which often occurs as a result of perinatal hypoxia-ischemia (H-I), is categorized depending on clinical presentation, brain region involvement and extent of involvement. In order to test different brain region involvement, this study investigates individual and multi-joint involvement in a rabbit model of CP. Pregnant rabbits at 70% gestation were subjected to 40-min uterine ischemia. Newborn rabbit kits were subjected to a swim test at 5 time points over the first 11 days of life. H-I kits were divided into hypertonic and non-hypertonic groups based on muscle tone at birth. The ranges and velocity of angular movement of the forelimb and hind limb joints (wrist, elbow, shoulder, ankle, knee and hip) during supported swimming were determined. Severely impaired (hypertonic) animals have significantly reduced range and angular velocity of joint motion, which do not improve over time. The non-hypertonic group showed deficits in wrist and hind limb movements that were not evident on prolonged observation. Preventive treatment with an inhibitor of neuronal nitric oxide synthase decreased the incidence of severely impaired kits; the non-hypertonic kits showed a different pattern of swimming. Supported swimming allows quantification of limb and joint motion in the principal plane of movement in the absence of weight bearing and decreases the need for balance control. Identification and quantification of milder deficits allows mechanistic studies in the causation of H-I injury as well as estimation of recovery with therapeutic agents.

Traveller health: prevalence of diabetes, pre diabetes and the metabolic syndrome

Irish Travellers are an ethnic minority group exposed to a myriad of social and health inequalities. Their current life expectancy equals that of the background population in the 1940s and one of the main causes of death is cardiovascular disease (CVD). There is a paucity of information on CVD risk factor assessment in the research literature in this population. This study assesses the prevalence of Diabetes, Pre-Diabetes and the Metabolic Syndrome (MetS) in a sample population from this community. Working with the Galway Traveller Movement, and following an overnight fast we measured fasting plasma glucose, HDL-cholesterol and Triglycerides. In addition weight, height, waist circumference (WC) and blood pressure (BP) were recorded. Of the 47 subjects, there were 4 (8.5%) participants identified as having diabetes, 5 (10.6%) pre-diabetes and 25 (53.2%) with the metabolic syndrome. The point prevalence of diabetes was calculated as 8.5%, pre-diabetes 10.6% and the metabolic syndrome 53.2%. In addition abdominal obesity was present in 70% and hypertension in 43%. Targeted screening for glucose abnormalities and traditional CVD risk factors is needed. Based on current literature, appropriate interventions might reasonably be expected to lower mortality and increase life expectancy.

Interethnic differences in Cyp3A4 inhibition by ketoconazole on docetaxel pharmacokinetics (PK) and pharmacodynamics (PD)

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Background: Use of concomitant medications that inhibit drug metabolizing enzymes such as Cyp3A4 is common and may affect chemotherapy PK/PD. We studied the effects of Cyp3A4 inhibition with ketoconazole on docetaxel PK/PD in 3 Asian ethnic groups. Methods: Two cohorts of chemonaive breast cancer patients were compared. The first cohort comprised of 95 patients (62 Chinese, 26 Malay, 7 Indian) treated with 75mg/m2 docetaxel unmodulated by ketoconazole, while the second cohort comprised of 31 patients (14 Chinese, 14 Malay, 3 Indian) treated with docetaxel 70mg flat dose modulated by oral ketoconazole, a regimen we previously reported to result in comparable docetaxel AUC as 75mg/m2 docetaxel. Plasma docetaxel concentrations were obtained at 0, 0.5, 1, 2, 5, 7 and 24 hours, and blood counts monitored on days 8 and 15 of cycle 1. Results: No significant differences in docetaxel PK or neutropenia between the races were observed in response to 75mg/m2 docetaxel unmodulated by ketoconazole (docetaxel clearance 36.4±16.9, 34.3±12.5, 44.2±27.7L/h, p=0.702; docetaxel AUC 3.6±2.7, 3.5±1.2, 2.9±1.3mg/L h, p=0.418; day 8 neutrophil count 0.5±0.6, 0.8±0.8, 0.4±0.3x109/L, p=0.138; grade 4 neutropenia 66%, 50%, 86%, p=0.157). In contrast, when docetaxel was administered with ketoconazole to inhibit Cyp3A4, inter-ethnic differences in docetaxel PK/PD were observed, with Chinese having the lowest docetaxel clearance and highest docetaxel AUC, followed by Malays and Indians (docetaxel clearance 18.6±5.7, 23.7±9.3, 30.6±6.7L/h, p=0.048; p=0.017 trend test; docetaxel AUC 4.2±1.4, 4.1±3.9, 2.4±0.5 mg/L h, p=0.048, p=0.017 trend test), although there were no statistically significant differences in body weight or surface area between the races. In concordance, Chinese patients experienced greatest degree of myelosuppression, followed by Malays and Indians (day 8 neutrophil count 0.8±0.8, 1.5±1.1, 1.7±1.1x109/L, p=0.046, p=0.013 trend test), and were more likely to develop grade 4 neutropenia (57%, 14%, 0%, p=0.024) from docetaxel + ketoconazole. Conclusions: Inter-ethnic differences in CYP3A inhibition by ketoconazole exist, and are important when evaluating the impact of concomitant medications with chemotherapy that may inhibit Cyp3A4.

No significant financial relationships to disclose.

Use of peripheral blood genomic markers whose expression levels reflect that of breast tumor genomic markers to predict drug treatment and sensitivity

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Background: Tumor gene expression signatures have been used to predict drug response, and we have previously reported drug-induced signatures to be more informative than the untreated baseline signatures. However, repeated tumor sampling during treatment is not feasible for most patients. We studied peripheral mononuclear cell (PBMC) gene expression levels in association with tumor gene expression levels in an attempt to identify peripheral blood markers that may serve as more accessible surrogates to predict drug treatment and response. Methods: Chemonaive breast cancer patients were treated with an alternating sequential regimen of doxorubicin and docetaxel and randomized to start with either drug. RNA from primary tumor before and 3 weeks, and from PBMC before and 24 hours after the first cycle of each drug was hybridized on the Affymetrix HG-U133+2 array containing 54,675 probe sets. Results: Pre- and post-treatment tumors from 47 patients were studied, including 35 with paired PBMC samples. 230 pre- and 85 posttreatment PBMC probe sets showed strong correlation in expression level (Pearson correlation coefficient >0.9) with the corresponding pre- and posttreatment tumor probe set, and included genes involved in transcription regulation and binding. Of the 975 tumor probe sets whose changes distinguished doxorubicin from docetaxel treatment, 12 corresponding PBMC probe sets were identified (p < 0.001) whose changes at 24 hours distinguished the two treatments with 77% accuracy. Of the 1,081 and 1,526 tumor probe sets whose changes predicted treatment response to doxorubicin and docetaxel, 19 and 15 informative PBMC probe sets predicted response to each drug with 100% and 80% accuracy, and included TNF receptor associated protein 1 and trefoil factor 1 for doxorubicin-, and folliculin and dynein for docetaxel-response. When the PBMC probe sets were validated in an independent test set treated with docetaxel (n = 23), 87% was correctly classified as docetaxel-treated, while 89% of non-responders clustered together. Conclusions: Peripheral blood contains genomic markers whose expression levels closely reflect that of breast tumor markers, and may be promising as surrogates to predict drug treatment and sensitivity.

No significant financial relationships to disclose.

Selective neuronal nitric oxide synthase inhibitors and the prevention of cerebral palsy

OBJECTIVE

To design a new class of selective neuronal nitric oxide synthase (NOS) inhibitors, and demonstrate that administration in a rabbit model for cerebral palsy (CP) prevents hypoxia-ischemia-induced deaths and reduces the number of newborn kits exhibiting signs of CP.

METHODS

We used a novel computer-based drug design method called fragment hopping to identify new chemical entities, synthesized them, and conducted in vitro enzyme inhibition studies with the three isozymes of NOS and in vivo experiments to monitor cardiovascular effects on pregnant rabbit dams, NOS activity, and NO(x) (NO and NO(2)) concentration in fetal brain, and assess neurobehavioral effects on kits born to saline- and compound treated dams.

RESULTS

The computer-based design led to the development of powerful and highly selective compounds for inhibition of neuronal NOS over the other isozymes. After maternal administration in a rabbit model of CP, these compounds were found to distribute to fetal brain, to be nontoxic, without cardiovascular effects, inhibit fetal brain NOS activity in vivo, reduce NO concentration in fetal brain, and dramatically ameliorate deaths and number of newborn kits exhibiting signs of CP.

INTERPRETATION

This approach may lead to new preventive strategies for CP.