Vessel-encoded arterial spin-labeling using pseudocontinuous tagging.

A new signal-to-noise ratio (SNR) efficient method is introduced for the mapping of vascular territories based on pseudocontinuous arterial spin labeling (ASL). A pseudocontinuous tagging pulse train is modified using additional transverse gradient pulses and phase cycling to place some arteries in a tag condition, while others passing through the same tagging plane are in a control condition. This is combined with a Hadamard or similar encoding scheme such that all vessels of interest are fully inverted or relaxed for nearly all of the encoding cycles, providing optimal SNR. The relative tagging efficiency for each vessel is measured directly from the ASL data and is used in the decoding process to improve the separation of vascular territories. High SNR maps of left carotid, right carotid, and basilar territories are generated in 6 min of scan time.     

Multifocal calcifying epithelial odontogenic tumor.

The calcifying epithelial odontogenic tumor (CEOT), or Pindborg tumor, is a rare and benign odontogenic neoplasm that affects the jaw. The most common manifestation of CEOT is a unifocal or localized lesion of the involved jaw, which may appear clinically as a hard tissue swelling and radiographically as a mixed radiolucent-radiopaque mass. In this article, we present a unique case of CEOT affecting multiple sites in the maxilla and mandible of a 51-year-old white man. Though biopsy samples from all involved sites revealed similar histopathologic features consistent with CEOT, the fact that there was a multifocal presentation is an unusual phenomenon for CEOT and has never been reported. Multifocal odontogenic lesions are not typical but have been observed in conditions associated with known genetic mutations. For example, multiple odontogenic keratocysts are the most common feature of the inherited condition known as nevoid basal cell carcinoma syndrome. This case, however, is the first one to demonstrate that there may be a multifocal variant of CEOT that has not been previously recognized.     

Suicide and unemployment: what are the missing links?

The suicide rate has been paralleled by an upward trend of unemployment in Hong Kong since 1997. This study aims to explore the unknown suicide-related factors among the unemployed. This information is useful in developing culturally specific suicide prevention initiatives related to unemployment. Seventy-six suicide deceased and 15 life subjects who were unemployed were selected from a previous psychological autopsy study. Logistic regression models were employed to estimate the relative suicide risks among the unemployed people. Among the unemployed, the suicide deceased were more likely to be male, had suffered from psychiatric illness, and had attempted suicide before. They also had acquired less competent social problem solving skills. Comparison with a small control group creates a generalizability problem. Suicide prevention for the unemployed could be done through mental health awareness programs; problem-solving skills training for attempters and males; and vocational training and job opportunities for discharged psychiatric patients and rehabilitees.     

Poststroke DNA immunization against neurite growth inhibitors is beneficial to the recovery from local cerebral ischemia in rats

BACKGROUND： Inhibitory signals, i.e. neurite growth inhibitors （NGIs）, presenting on central nervous system （CNS） myelin have been shown to play a crucial role in inhibiting lesioned axonal sprouting and leading to less functional recovery. Vaccines targeting NGIs may provide multifactorial protection against brain insults by overcoming the inhibitory effects of these NGIs and boosting the body＇s immune repair mechanisms. OBJECTIVE： To evaluate the effect of poststroke DNA immunization against NGIs on the rehabilitation for sensorimotor function of rat models of local cerebral ischemia. DESIGN： Completely randomized grouping design, and controlled experiment. SETTING： Brain Injury Research Laboratory, Department of Neurosurgery, National Neuroscience Institute, Singapore. MATERIALS： Sixty adult male Sprague-Dawley rats ranging in age from 45 to 120 days and in weight from 180 to 250 grams were provided by Animal Center of Department of Anatomy, Faculty of Medicine, National University of Singapore. pcDNA3.1（＋）-neurite growth inhibitors （pcDNA-NGIs） a gift was provided by Dr. Xiao from Department of Clinical Research, Singapore General Hospital, Singapore. METHODS： The experiment was carried out at Brain Injury Research Laboratory, Department of Neurosurgery, National Neuroscience Institute, Singapore from August 2003 to April 2005. （1）The involved rats were randomized into 3 groups： pcDNA-NGIs group （group A）, pcDNA3.1 （＋） group （group B） and model group （group C）, with 20 rats in each group. Left focal cerebral ischemia （FCI） was permanently induced through middle cerebral artery occlusion （MCAO） with the assistance of an operating microscope. Successful MCAO was determined by a 20% decrease to baseline in the ipsilateral cerebral blood flow. 100 μg of pcDNA-NGIs eluted in phosphate-buffered saline （PBS） was intramuscularly injected into the tibial muscle once a week after MCAO for 6 weeks in group A. As control, pcDNA3.1 （＋） was also administrated in the same way in group B and nothing was administrated in group C. （2） The modified neurological severity score （mNSS）, a composite of motor, sensory, reflex and balance tests, was used to test the sensorimotor deficit. The mNSS was graded on a scale of 0 - 18, i.e. normal score was 0, maximal deficit score was 18, and 1 point was warded for the inability to perform the tasks or the lack of a tested reflex. （3） The newly generated axons of corticorubral projection were traced by stereotaxic guided injection of 100 g/L biotinylated dextran amine. Rats were sacrificed two weeks after tracing, and cryostat coronal sections of midbrains （30μm） were reacted to BDA according to the manufacturer＇s instruction by the free-floating method. Images were captured on a DM RXA2 LEICA Microscope with a Spot Digital Camera system （Germany）, and the numbers of labeled axons on the denervated side in four standard coronal sections including the red nucleus were manually quantified. MAIN OUTCOME MEASURES： （1） The number of newly generated axons of corticorubral projection. （2）The improvement in sensorimotor deficit. RESULTS： All the involved 60 rats entered the stage of final analysis. （1） The number of newly generated axons of corticorubral projection of rats： Only ipsilateral axons of CRP were noted with little evidence of fibers crossing to the contralateral red nucleus in rats of groups B and C. More BDA-positive fibers crossing the midline and terminating in the contralateral red nucleus in appropriate target areas mirroring the non-differentiated red nucleus were found in rats of group A. Quantitative analysis showed that BDA-labeled axons in the denervated side of rats in group A were more than those in group B （P 〈 0.05）. （2） Improvement in sensorimotor deficit of rats： At 2 weeks after immunization, significant improvement in sensorimotor deficit was found in rats of group A. There were significant differences of improvement in sensorimotor deficit of rats between group A and group B or group C at 12 and 14 weeks after immunization （P 〈 0.05）. CONCLUSION： （1） Poststroke DNA immunization against NGIs leads to increased sensorimotor recovery following FCI and compensatory newly growth of axons from corticorubral projection.     

Generation of platelet activating factor (PAF) by a human lung epithelial cell line

A human lung epithelial cell line (ATC-CCL-185) was cultured in nutrient Ham-F12 medium. Cells in monolayers were stimulated with either ionophore A23187 (1 microM) or phorbol myristate acetate (PMA, 0.2 microM) for various periods of time. Samples were analysed by HPLC and the presence of platelet activating factor (PAF) was detected by bioassay of the release of [3H]serotonin from rabbit platelets undergoing aggregation. The ATC-CCL 185 cells were found to synthesize PAF following activation with either PMA or ionophore. Ionophore at 1 microM was found to be more potent than PMA at 0.2 microM in the induction of PAF synthesis (congruent to 80 ng/mg protein). The synthesis of PAF through ionophore stimulation reached a maximum at 5 min, whereas PMA stimulation peaked at 15-20 min. PMA induced approximately one third the level of PAF synthesis by the ionophore. The PAF synthesized by these CCL185 cells was found to be mainly associated with the cell membrane with less than 10% released into the medium. Release of PAF into cell supernatant was dependent on the presence of bovine serum albumin (BSA). In the absence of BSA, a large portion (approximately 90%) of PAF was found to be cell associated, and only 60% when BSA concentration reached greater than or equal to 0.2%. These results demonstrate the ability of this lung epithelial cell line to synthesis PAF thus, suggesting that epithelial cells might participate in the process of inflammatory lung diseases, through the generation of this important mediator.     

High molecular weight aggregate from cataractous and normal human lenses: characterization by antisera to lens crystallins

High molecular weight and low molecular weight fractions were obtained from total soluble proteins of human cataractous and normal lens nuclei. These fractions were analyzed using a solid phase radioimmunoassay that employed monospecific antisera to alpha, beta and gamma crystallins. Relative to the high molecular weight fraction from normal lens nuclei, the high molecular weight fraction from cataractous lens nuclei showed decreased binding to antisera specific for beta and gamma crystallins. These results demonstrate that the polypeptides of the high molecular weight fraction comprise a special class of polypeptides that have preferentially undergone covalent and/or structural changes during the process of human cataractogenesis.     

B-cell and T-regulatory cell dysfunction in six Chinese children with hypogammaglobulinaemia

We report six Chinese boys with hypogammaglobulinaemia. All but one had very low or undetectable circulating B-lymphocytes, two had reversed CD4/CD8 ratios (in one of whom this later became normal), one had reduced lymphocyte proliferative responses to concanavalin A and pokeweed mitogen and three had deficient responses to OKT3. Generation of antibody-secreting cells in response to pokeweed mitogen was markedly defective in all patients. Co-cultures of purified lymphocyte subsets from the patients with those of normal donors revealed that in addition to B-cell deficiency seen in all patients, two had T-helper cell deficiency and two had T-suppressor cell hyperactivity. One of the latter patients was treated with cimetidine in an attempt to ablate histamine type 2 receptor-bearing suppressor cells: the absolute number of such cells was temporarily reduced but there was no concurrent correction of the functional hyperactivity. These studies point to the variable nature of T-regulatory cell deficiencies in hypogammaglobulinaemia.     

Comparison of Simulated and in-Vivo Plasma Levels of Cilastatin Following Intravenous in-Line Drug Administration

The primary objective of this work was to establish a method to simulate the plasma levels of cilastatin, a model drug, following an intravenous in-line delivery scheme. In-vivo data in dogs obtained from this work were used to demonstrate the validity of the proposed approach. The in-line drug delivery system consists of a drug containing device which is placed between a large volume parenteral and a patient. Numerous advantages have been identified for this automatic in-line reconstitution delivery system. The numerical convolution integral algorithm was used in this work to perform plasma profile simulation. The results indicated that the simulated cilastatin plasma profile following in-line delivery closely agreed with the in-vivo data.