Apical endocytosis of ricin in MDCK cells is regulated by the cyclooxygenase pathway.

Addition of arachidonic acid or stimulation of arachidonic acid production by secretory phospholipase A2 selectively upregulated apical endocytosis of ricin in MDCK cells without affecting basolateral endocytosis. Electron microscopic studies revealed that MDCK cells treated with secretory phospholipase A2 and incubated with horseradish peroxidase had an increased number of normal appearing peroxidase-labeled endosomes and no sign of membrane ruffling. Moreover, inhibition of basal arachidonic acid release, either by decreasing the cytosolic phospholipase A(2) activity or the diacylglycerol lipase activity, reduced the rate of apical endocytosis.

Preliminary evaluation of two fluorescence imaging methods for the detection and the delineation of basal cell carcinomas of the skin.

Background And Objective: Fluorescence techniques can provide powerful noninvasive means for medical diagnosis, based on the detection of either endogenous or exogenous fluorophores. The fluorescence of delta-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) has already shown promise for the diagnosis of tumors. The aim of the study was to investigate the localization of skin tumors after the topical application of ALA, by detecting the PpIX fluorescence either in the spectral or in the time domain.

DNA bending by photolyase in specific and non-specific complexes studied by atomic force microscopy.

Specific and non-specific complexes of DNA and photolyase are visualised by atomic force microscopy. As a substrate for photolyase a 1150 bp DNA restriction fragment was UV-irradiated to produce damaged sites at random positions. Comparison with a 735 bp undamaged DNA fragment made it possible to separate populations of specific and non-specific photolyase complexes on the 1150 bp fragment, relieving the need for highly defined substrates.

Intraprotein electron transfer between tyrosine and tryptophan in DNA photolyase from Anacystis nidulans.

Light-induced electron transfer reactions leading to the fully reduced, catalytically competent state of the flavin adenine dinucleotide (FAD) cofactor have been studied by flash absorption spectroscopy in DNA photolyase from Anacystis nidulans. The protein, overproduced in Escherichia coli, was devoid of the antenna cofactor, and the FAD chromophore was present in the semireduced form, FADH., which is inactive for DNA repair.

Mesenteric ischemia after coronary artery bypass grafting: should local continuous intra-arterial perfusion with papaverine be regarded as a treatment?

Mesenteric ischemia after cardiac surgery is rare but dramatic. We present a patient who had acute mesenteric ischemia following low cardiac output after coronary artery bypass grafting. Our patient was successfully treated with continuous intra-arterial perfusion with papaverine.

Mammalian Cry1 and Cry2 are essential for maintenance of circadian rhythms.

Many biochemical, physiological and behavioural processes show circadian rhythms which are generated by an internal time-keeping mechanism referred to as the biological clock. According to rapidly developing models, the core oscillator driving this clock is composed of an autoregulatory transcription-(post) translation-based feedback loop involving a set of 'dock' genes. Molecular clocks do not oscillate with an exact 24-hour rhythmicity but are entrained to solar day/night rhythms by light.

Clinical spectral characterisation of colonic mucosal lesions using autofluorescence and delta aminolevulinic acid sensitisation.

Background And Aims: Laser induced fluorescence (LIF) from colonic mucosa was measured in vivo with and without delta aminolevulinic acid (ALA) in an attempt to differentiate between neoplasia and non-neoplasia in real time during colonoscopy.

Methods: Spectra from 32 adenomas, 68 normal sites, and 14 hyperplastic polyps in 41 patients were obtained with a point monitoring system. Twenty one of the patients had been given a low dose of ALA as a photosensitiser before the examination.

A putative blue-light receptor from Drosophila melanogaster.

A gene encoding a 62.5 kDa homolog of Drosophila melanogaster photolyase was isolated. Purified recombinant protein contained a flavin adenine dinucleotide chromophore.

Does the extended use of arterial grafts compromise the myocardial recovery after coronary artery bypass grafting in left ventricular dysfunction?

Objective: To assess the prognostic factors of myocardial recovery expected after coronary bypass surgery and the impact of surgical technique used, a prospective non-randomized study including a 1-year postoperative evaluation of left ventricular function was performed in patients with left ventricular dysfunction (left ventricular ejection fraction (LVEF) < 0.40).

Methods: From 1993 to 1996, 110 patients (mean age 61+/-11 years) were included in the study.

Improved outcome after severe head injury with a new therapy based on principles for brain volume regulation and preserved microcirculation.

Objective: To assess the new "Lund therapy" of posttraumatic brain edema, based on principles for brain-volume regulation and improved microcirculation.

Design: A prospective, nonrandomized outcome study over a 5-yr period on severely head-injured patients with increased intracranial pressure, comparing the results with a historical control group with the same selection criteria for patients who were treated according to conventional principles.

Setting: General intensive care unit of a university hospital.

[Long-term outcome of mitral valve repair of dystrophic mitral regurgitation].

Between January 1984 and December 1994, 130 patients underwent mitral valvuloplasty for pure dystrophic mitral regurgitation. There were 94 men and 36 women with a mean age of 61 +/- 9 years: 52 patients were in atrial fibrillation; 91% of patients were in NYHA Classes III or IV. At preoperative echocardiography, the regurgitation was assessed as Grade III or IV and classified using the Carpentier classification according to type I (dilatation of the annulus) or II (mitral valve prolapse); 95% of patients had isolated prolapse of the posterior leaflet, 3% had isolated prolapse of the anterior leaflet and 2% had prolapse of the two leaflets.

Xeroderma pigmentosum group C protein complex is the initiator of global genome nucleotide excision repair.

The XPC-HR23B complex is specifically involved in global genome but not transcription-coupled nucleotide excision repair (NER). Its function is unknown. Using a novel DNA damage recognition-competition assay, we identified XPC-HR23B as the earliest damage detector to initiate NER: it acts before the known damage-binding protein XPA.

Direct visualization of dynamic protein-DNA interactions with a dedicated atomic force microscope.

Photolyase DNA interactions and the annealing of restriction fragment ends are directly visualized with the atomic force microscope (AFM). To be able to interact with proteins, DNA must be loosely bound to the surface. When MgCl2 is used to immobilize DNA to mica, DNA is attached to the surface at distinct sites.

Relationship of the xeroderma pigmentosum group E DNA repair defect to the chromatin and DNA binding proteins UV-DDB and replication protein A.

Cells from complementation groups A through G of the heritable sun-sensitive disorder xeroderma pigmentosum (XP) show defects in nucleotide excision repair of damaged DNA. Proteins representing groups A, B, C, D, F, and G are subunits of the core recognition and incision machinery of repair. XP group E (XP-E) is the mildest form of the disorder, and cells generally show about 50% of the normal repair level.

Two human homologs of Rad23 are functionally interchangeable in complex formation and stimulation of XPC repair activity.

XPC-hHR23B protein complex is specifically involved in nucleotide excision repair (NER) of DNA lesions on transcriptionally inactive sequences as well as the nontranscribed strand of active genes. Here we demonstrate that not only highly purified recombinant hHR23B (rhHR23B) but also a second human homolog of the Saccharomyces cerevisiae Rad23 repair protein, hHR23A, stimulates the in vitro repair activity of recombinant human XPC (rhXPC), revealing functional redundancy between these human Rad23 homologs. Coprecipitation experiments with His-tagged rhHR23 as well as sedimentation velocity analysis showed that both rhHR23 proteins in vitro reconstitute a physical complex with rhXPC.

Crystal structure of DNA photolyase from Anacystis nidulans.

The crystal structure at 1.8 A resolution of 8-HDF type photolyase from A. nidulans shows a backbone structure similar to that of MTHF type E.

Influence of a 3-week psychiatric training programme on attitudes toward mental illness in medical students.

The present study was carried out to assess the influence of psychiatric training, including direct patient contact, on attitudes toward mental illness. An experimental group consisting of medical students going through their 3-week training in psychiatry was compared with a control group going through training in ophthalmology. The psychiatric training involved direct patient contact and course work.

Cloning, tissue expression, and mapping of a human photolyase homolog with similarity to plant blue-light receptors.

Enzymatic photoreactivation is a DNA repair mechanism that removes UV-induced pyrimidine dimer lesions by action of a single enzyme, photolyase, and visible light. Its presence has been demonstrated in a wide variety of organisms, ranging from simple prokaryotes to higher eukaryotes. We have isolated a human gene encoding a 66-kDa protein that shows clear overall homology to known bacterial photolyase genes.

Changing epidemiology of measles in Turkey: need for reassessment of measles vaccination policy?

Changing epidemiology of measles in Turkey and in Izmir city, since the introduction of measles vaccine was examined in order to evaluate the need for new strategies to control measles infection. After the National Vaccination Campaign in 1985, the rates of incidence and mortality dropped to 4.2/100000 and 0/million, respectively, in 1987.

Effect of calmodulin antagonists on endocytosis and intracellular transport of ricin in polarized MDCK cells.

The effect of calmodulin antagonists on endocytosis, transcytosis, recycling, and transport to the Golgi apparatus from both the apical and the basolateral plasma membrane of polarized Madin-Darby canine kidney cells has been investigated by using the plant toxin ricin as a membrane marker. The calmodulin antagonists trifluoperazine and N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) stimulated apical endocytosis of ricin, whereas basolateral endocytosis was unaffected. A stimulation of the apical uptake of the fluid-phase marker horseradish peroxidase by calmodulin antagonists was also found both by biochemical and by ultrastructural studies.

Intracardiac air clearing in valvular surgery guided by transesophageal echocardiography.

Background And Aims Of The Study: Air embolism during open heart surgery seems to be a common occurrence and may be responsible for neuropsychological deficit or myocardial damage.

Material And Methods: Forty-two consecutive patients undergoing valvular surgery were studied using the long axis view of the heart by two dimensional transesophageal echocardiography (TEE). The patients were randomized into two groups of 21 each.