Scanning tunneling microscopy imaging was applied to long-chain fatty acids, their derivatives and cholesteryl stearate in the adsorbed state at the liquid-solid interface between phenyloctane and highly oriented pyrolytic graphite. Cerotic acid, lignoceric acid, stearic acid, sodium stearate, stearoyl amide, and stearoyl anilide all produced regular arrays of dark and bright bands. Bright bands in the images of all execept the last compound were assigned as side-by-side alignment of hydrocarbon chains based on the variation of the band width between the three fatty acids. In the case of stearoyl anilide, the bright part was assigned to aromatic ring structure and the wider dark area to the hydrocarbon part.
Bacteriophage T4 was imaged by atomic force microscopy with the finest resolution to date with a clear image of tail fibers of an estimated diameter of 2–3 nm. T4 phages were spread on a clean surface of silicon wafer and dried under air before observation with an atomic force microscope. The head, tail and tail fibers were routinely imaged with somewhat distorted dimensions. The ease of imaging isolated phage particles with a good resolution raised our expectation for the further use of AFM in biomedical applications.
A 25-year-old Japanese woman who had been suffering from systemic lupus erythematosus (SLE) for 12 years was admitted to our hospital with a suspected diagnosis of peritonitis after suddenly developing severe abdominal pain and distention which could not be relieved by treatment with anodyne. Noninvasive examinations did not provide enough evidence to rule out acute appendicitis, bowel perforation, or ischemia due to vasculitis. Therefore, in consideration of the severity of her uncontrollable abdominal pain, an exploratory laparotomy was performed. The operative findings revealed nonbacterial peritonitis with a large amount of ascites and an edematous small bowel. No perforation of the intestine was found. On post-operative day (POD) 3, the severe abdominal pain redeveloped, but responded well to steroid pulse therapy. Based on the operative findings and her clinical course, the most likely diagnosis was thought to be acute lupus peritonitis. It is often difficult to ascertain whether abdominal pain in an SLE patients is due to lupus peritonitis or to an underlying cause requiring surgery. Thus, it is essential that continuous and careful assessment of the surgical abdomen is performed when a patient with SLE develops acute abdominal pain, and if a surgical condition cannot be ruled out, a laparotomy should be performed without delay.
Cross stimulation in a dual chamber pacing system, in which the atrial stimulus intermittently captured the right ventricle, occurred immediately after pacemaker implantation in a 71-year-old man. It was prevented temporarily by reducing the pacing rate so that P wave synchronous ventricular (VDD) pacing resulted and by reducing the output of the atrial circuit from 5 to 4 volts. Cross stimulation disappeared spontaneously 14 days after surgery.
Novel scanning near-field optical microscopy/atomic force microscope probes by combined micromachining and electron-beam nanolithography Summary Abstract: Atomic force microscopy studies of frictional forces and of force effects in scanning tunneling microscopy J.Atomic force microscopy and scanning tunneling microscopy were used to obtain molecular resolution images of biological structures such as proteins and viruses. Proteins of 10 to 20 nm scale could be reliably resolved with faintly recognizable subunit arrangements. Bacteriophage T4 was imaged with well-resolved head, tail, and tail fibers. When the tails were prepared from the headless mutants, the sheath proteins were stripped away from the tail, revealing the tube and the base plate in a T-shaped complex, Scanning tunneling microscopy was used on metal coated samples and provided a reliable height measurement for bacteriophage T4. Constant improvement in the instrumentation and sample preparation promises a bright future for the biomedical application of scanning probe microscopy.
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