Low density lipoprotein receptor expression on keratinocytes in normal and psoriatic epidermis

Biochemical and morphologic studies on the interaction of low density lipoprotein (LDL) with cultured normal keratinocytes and squamous carcinoma cells have shown a negative correlation between LDL receptor activity and terminal differentiation of the epidermal cells [Ponec M et al, J Invest Dermatol 83:436-440, 1984 and Vermeer, BJ et al, J Invest Dermatol 86:195-200, 1986]. Whether such in vitro studies pertain to the epidermis in vivo is not known. To obtain information on the distribution of LDL receptors in the epidermis in situ, morphologic studies were performed using LDL-gold as an ultrastructural marker. When freshly isolated mouse and human epidermal cells were incubated with LDL-gold complexes, only keratinocytes with the morphologic characteristics of basal cells showed binding and uptake of LDL-gold. No LDL receptor activity was found on Langerhans cells, melanocytes or highly differentiated keratinocytes. Since cell separation techniques can destroy receptors, the staphylococcal epidermolytic toxin was utilized to produce intercellular and intra-epithelial splitting of the epidermis. In preparations of both normal mouse and human epidermis, LDL-gold binding was restricted to basal cells and a few suprabasal keratinocytes. In contrast, in psoriatic epidermis, and to a lesser extent, essential fatty acid-deficient mouse epidermis, cells in the stratum spinosum showed abundant LDL-gold binding. Thus LDL-gold may be a useful marker for epidermal differentiation.     

Patient expectations of radiology in noninteractive encounters

Open-ended interviews with 107 patients documented specific patient expectations of radiologic procedures during which there was no direct radiologist-patient interaction. Patient expectations could be classified into those related to the facility and those related to interactions with radiology staff. Among facility-related expectations, waiting time far outweighed all other concerns. Interpersonal skills were the predominant expectation of radiology staff. The role of the radiologist in fulfilling patient expectations was less clear. Only 10% of unprompted patients cited the radiologist as a factor in their expectations. When patients were specifically prompted to discuss the radiologist's role, communication skills, accuracy of interpretation, and interpersonal skills were the predominant concerns.     

唐松草新碱水溶液的氧化降解动力学研究

本文研究了唐松草新碱在水溶液中的氧化降解动力学。考查了pH值、离子强度、温度和氧含量的影响,水溶液中的氧化降解速率常数由荧光法测定。结果表明,唐松草新碱在过量氧存在下,其氧化降解反应服从假一级反应动力学方程式,速率常数可由下式表示:其速率常数主要受介质的pH值和氧含量的影响,在pH 7.2条件下没有观测到原盐效应。     

Cytochemical and biochemical localization of lipase and sphingomyelinase activity in mammalian epidermis

Despite a wealth of new information on epidermal lipids and their role in permeability barrier function and desquamation, little is known about the location of the enzymes that regulate their catabolism. In this study we have localized lipase (triacylglycerol hydrolase) and sphingomyelinase in the outer epidermis simultaneously by cytochemical and cell fractionation techniques. Aldehyde-fixed tissues (100-microns slices) incubated in either Tween 85 or triolein plus taurocholate/calcium chloride-containing buffer, pH 7.2 or 4.5, were then exposed to lead to form insoluble soaps, and processed for electron microscopy. Simultaneously, cell homogenates and isolated lamellar body fractions were incubated with methylumbelliferyl oleate under similar conditions, with released, free methylumbelliferone serving as an index of lipase activity. On electron microscopy and cell fractionation, both lipase and sphingomyelinase were localized primarily to intercellular domains in the stratum corneum. In the stratum granulosum lipases were found, both ultrastructurally and biochemically, in lamellar bodies and ultrastructurally in both the perinuclear cistern and mitochondria. In summary, these studies: by demonstrating lipid-catabolic enzymes in the intercellular domains of the stratum corneum, lend further support to the 2-compartment model of the stratum corneum; provide new information about the location of lipid-catabolic enzymes in differentiating epidermis; and provide insights about how lipids are processed during permeability barrier formation and desquamation.     

The partial opioid agonist, buprenorphine, protects against lethal effects of cocaine.

Buprenorphine (0.3-3.0 mg/kg) produced dose-dependent protection against the lethal effects of cocaine in mice. The (+)-enantiomer of buprenorphine did not protect up to doses over 100 times greater than the lowest effective dose of its (-)-enantiomer. The protective effects were also produced by the opioid agonists morphine and methadone, but not by the opioid antagonist, naltrexone. Low doses of naltrexone (0.3-1.0 mg/kg) blocked the protective effects of buprenorphine. Protection conferred by buprenorphine was not observed in CXBK mice, a recombinant inbred strain relatively devoid of mu-opioid receptors. Thus, buprenorphine appears to protect against the lethal effects of cocaine by a process mediated by mu-opioid receptors. The present results should provide some additional safety assurance in future clinical trials with buprenorphine, especially in outpatient trials where cocaine abuse may continue along with treatment.     

The effects of anterior temporal lobectomy (ATL) on the middle-latency auditory evoked potential (MLAEP).

The anatomical and physiological origins of the middle-latency auditory evoked potential (MLAEP) are not well understood. The present investigation was conducted to determine whether the MLAEP derives its origins in part from the anterior temporal lobe. Twelve subjects with intractable seizures were evaluated with the MLAEP pre and post excision of the anterior-mesial temporal lobe (ATL) unilaterally. In our study, component Pa latency was unaffected by the ATL. The Na latency and the Na/Pa amplitude showed significant increases after ATL. The results we interpreted as being consistent with currently held beliefs regarding the origins of Pa. The changes in Na latency and Na/Pa amplitude are hypothesized to reflect a loss of the modulating influence of the cortex on the subcortical generators of Na.     

Treatment failure due to methicillin-resistant Staphylococcus aureus (MRSA) with reduced susceptibility to vancomycin.

We report the first instance in Australia of treatment failure due to a strain of methicillin-resistant Staphylococcus aureus (MRSA) with reduced susceptibility to vancomycin--heteroresistant vancomycin-intermediate S. aureus (hVISA). The infection occurred in a 41-year-old man with multiple risk factors. No transmission of the organism to other patients or the environment was detected. This case may herald the beginning of a new phase of staphylococcal resistance in Australia.     

Endovascular repair of the thoracic aorta in octogenarians.

Background: To evaluate the feasibility and safety of thoracic endografting in the octogenarian population. Methods: Between February 2000 and August 2005, 249 patients with a mean age of 69+/-12.3 years (range 23-91) underwent thoracic endografting. Forty-four patients (27 males and 17 females) were octogenarians with a mean age of 84+/-2.7 years. Indications for intervention included: atherosclerotic aneurysms (26/44, 59%), acute and chronic dissections (9/44, 20.5%), penetrating aortic ulcers (6/44, 14%) and contained rupture (3/44, 7%). Results: Endovascular repair was achieved in all octogenarian patients (44/44, 100%). Mean length of stay was 4.7+/-3.6 days. Two cardiac-related deaths and 1 retrograde dissection death occurred (3/44, 7%). Complications included hemiparesis (n=2) with full recovery at discharge, groin hematoma (n=1), pneumonia (n=2) and stroke (n=1) [6/44, 11%]. Endoleaks were diagnosed in 3 patients [3/44, 7%] (2 type I, 1 type II) at 30-day follow-up. Two patients developed an endoleak beyond 30 days [2/44, 5%] (1 type I, 1 type II). Two re-interventions were necessary at 30 days (1 type I, 1 type II). Mean follow-up was 22 months and there were no device migrations or aortic ruptures. No statistical differences in overall mortality were noted between octogenarians and non-octogenarians at 30 days (7% vs 6%, p=NS), 12 months (18% vs 13%, p=NS) and 24 months (27% vs 15%, p=NS). However, at 5 years post-procedure, octogenarians had a significantly higher overall mortality than non-octogenarians (32% vs 17%, p=0.038). Conclusions: Advanced age is not a contraindication to thoracic endografting with favorable short and mid-term outcomes compared to non-octogenarians.     

苦楝化学成份的研究

从苦楝(Melia azedarach L.)果中分得苦楝新醇(Ⅰ),苦楝醇(Ⅱ)、苦楝酮(Ⅲ)、苦楝二醇(Ⅳ)、香草醛(Ⅴ)和香草酸(Ⅵ)。根据波谱(IR,MS,¹HNMR,¹³CNMR)分析和理化常数测定,确定了它们的结构。其中苦楝新醇(Ⅰ)为新化合物,对菜青小虫有一定的拒食活性。