The lateral osteotomy in rhinoplasty: clinical and radiographic rationale for osteotome selection

A preferred osteotome for endonasal osteotomy would facilitate reliable, complete osteotomies with minimal soft-tissue trauma. In this report, a radiographic evaluation of the bony lateral nasal wall thickness along the track of a high-low-high osteotomy was undertaken to guide the determination of appropriate osteotome size. Bone window axial computed tomographic scans were evaluated in 56 patients with a mean age of 48 years (range, 19 to 86 years). The average thickness along the site of lateral osteotomy was determined to be 2.47 mm (standard deviation, 0.47) in male patients and 2.29 mm (standard deviation, 0.40) in female patients. On the basis of these data, clinical evaluation of prototype 3- and 2.5-mm low-profile guarded osteotomes was undertaken in comparison with a "standard" 4-mm low-profile guarded osteotome to assess both their reliability and the degree of intranasal trauma, as reflected by intranasal mucosal tears. Although 2- and 3-mm unguarded osteotomes are time-tested, they may be reliable only in the hands of the most experienced surgeons. Therefore, a low-profile guard was included in the osteotome design to allow the surgeon to engage the bone securely and minimize the risk of slippage. Forty patients underwent rhinoplasty, for a total of 80 lateral osteotomies; the mean age of the patients was 38 (range, 16 to 75). In all cases, lateral osteotomies were accomplished with one pass. The 4-mm osteotome causes intranasal mucosal tears in 95 percent of osteotomies, the 3-mm osteotome in 34 percent, and the 2.5-mm in 4 percent. Early postoperative edema and ecchymosis were comparable among the groups. One patient, who underwent osteotomies with a 4-mm osteotome, had excessive postoperative narrowing, possibly due to his wearing of eyeglasses earlier than directed. This report suggests that proper selection of osteotome and attention to proper surgical technique results in a reliable, minimally traumatic lateral osteotomy through the endonasal approach. The 2.5-mm osteotome was reliable and the least traumatic to soft tissue of the osteotomes evaluated.     

A tool and an instrument modification to facilitate aortic flow probe placement

A tool was designed and fabricated to simplify the procedure of placing a flow probe around the aortic root in acute animal experiments. The tool was made from a section of silicone rubber tubing which was flattened and tapered at one end. The flow probe was inserted into the open end of the tool, and the tapered end was drawn under the aorta, thus pulling the probe into position. Grooves were also ground into the probe body to ease the installation of the slot cover. During the 2 years that the tool and modified probes were used, they saved time and eliminated rupture of vessels as complications of aortic root flow probe placement.     

A newly designed tensile tester for cells and its application to fibroblasts

A tensile test system for cells has been designed and applied to fibroblasts from the rabbit patellar tendon. It consists of a thermostatic test chamber, an inverted fluorescence microscope, micromanipulators, a direct drive linear actuator, a cantilever-type load cell, and a video dimension analyzer (VDA). The test chamber and the microscope are mounted on a vibration isolator. A cell floated in Hanks' balanced salt solution of 37 degrees C is gripped with a pair of micropipettes which have very fine tips (outer diameter = 20 approximately 30 microm, inner diameter = 3 approximately 5 microm) and are coated with a cell adhesive, Cell-Tak, at their ends. One of the micropipettes is fixed to the load cell; the other one is attached to the linear actuator which is used to stretch the cell. Load applied to the cell is measured with the load cell, while elongation of the cell is determined with the VDA using the images of the ends of the micropipettes as markers. The measurement accuracy of the load cell was +/-0.05 microN. All the fibroblasts tested were firmly attached to the micropipettes during tensile testing, and showed local non-uniform deformation. The maximum load and elongation to failure of the cells were 0.9+/-0.2 microN and 86+/-24 microm, respectively.     

A newly designed oscillating viscometer for blood viscosity measurements

A newly designed type of oscillating viscometer is described. The viscometer consists of either a tube or a rod oscillating at a resonance frequency with amplitudes in the micro- and nanometer range. A fluid flowing through the tube or surrounding the rod damps the torsional oscillations. The increase in the damping depends on the viscosity of the fluid and is used to determine viscosity. It was found that viscosity measurements are feasible during blood flow. This new type of viscometer may be useful to the study of biophysical properties of blood at the wall surface during flow and give new insights into blood flow. The device allows direct viscosity measurement on blood directly as it is drawn from the vein through the tube without any anticoagulant.     

A single center experience with the newly designed R Stent in small coronary vessels

BACKGROUND: Over the past 10 years stents have been used more frequently for the treatment of de novo coronary artery stenosis. Initally these devices were used primarily in coronary arteries with diameters ranging from 3.0 to 4.0 mm. Traditionally, coronary arteries less than 3.0 mm in diameter were treated with only balloon angioplasty, due to the unavailablity of flexible, low profile, small diameter stents. In the past three years, many stents have been designed to be implanted in small coronary arteries. OBJECTIVE: The objective of this study was to evaluate the safety and feasiblity of the R Stent in patients with coronary lesions located in coronary arteries with a reference diameter 2.5-3.0 mm. METHODS AND RESULTS: Between November 1998 and September 1999, 32 patients with stable (37%) and unstable (63%) angina treated with the R Stent were included in this study. The treated lesions were in the right coronary artery (RCA) (n = 13), left cirumflex coronary artery (LCX) (n = 10), and left anterior descending coronary artery (LAD) (n = 9). Of these lesions thirteen were anatomically complex. Stent deployment was successful in 97% with one crossing failure in a patient with a vessel tortuosity of greater than 75 degrees of the circumflex artery. No post-procedual major adverse cardiac and cerebrovascular event (MACCE) occurred within 30 days of stent implantation. After the procedure, patients were scheduled for a two-week telephone follow-up and a one-month clinical evaluation. At 30 days, only one patient (3%) experienced the recurrence of angina Canadian cardiovascular society classification ((CCS) Class 2). All other patients were event and angina free. CONCLUSION: This first clinical experience in patients with small vessel disease shows that the use of the R stent is safe and feasible with low rates of acute stent thrombosis.     

An island biogeographical approach to the analysis of butterfly community patterns in newly designed parks

We analyzed the butterfly communities in the newly designed city parks (area C), “newly opened habitat islands”, of Tsukuba City, central Japan. The area constituted a natural ecological experiment on the mainland for clarifying the pattern and process of faunal immigration. We compared butterfly communities in area C with those in two other areas in the light of the theory of island biogeography and the concept of generalist/specialist. Our results showed the following: (1) Fewer species were found in area C than in other areas, due largely to the absence of many specialist types, restricted and habitat specialists, and/or low density species in the area. Generalist types, widespread and habitat generalists, and/or high density species predominated in area C. (2) The difference in the species numbers among the three sections within area C could be explained by the habitat structure in and around the respective sections. (3) The densities of many species were low in area C, probably due to its man-modified habitat structure. In particular, several species occurred at extremely low densities in area C, but at high densities in other areas. (4) The internal structure of the habitat island butterfly community in area C was almost perfectly consistent with that of “quasi-equilibrium” communities that appear during the colonization of an island. Our results demonstrate that the synergetic application of the generalist/specialist concept and the island biogeography theory is effective for the understanding of the patterns and structures of habitat island communities.     

Application of type synthesis theory to the redesign of a complex surgical instrument

Surgical instruments consist of basic mechanical components such as gears, links, pivots, sliders, etc., which are common in mechanical design. This paper describes the application of a method in the analysis and design of complex surgical instruments such as those employed in laparoscopic surgery. This is believed to be the first application of type synthesis theory to a complex medical instrument. Type synthesis is a methodology that can be applied during the conceptual phase of mechanical design. A handle assembly from a patented laparoscopic surgical stapler is used to illustrate the application of the design method developed. Type synthesis is applied on specific subsystems of the mechanism within the handle assembly where alternative design concepts are generated. Chosen concepts are then combined to form a new conceptual design for the handle assembly. The new handle assembly is improved because it has fewer number of parts, is a simpler design and is easier to assemble. Surgical instrument designers may use the methodology presented here to analyze the mechanical subsystems within complex instruments and to create new options that may offer improvements to the original design.     

A newly designed and constructed 20 kHz magnetic field exposure facility for in vivo study

Exposure to man-made electromagnetic fields has increased over the past century. As a result of exposure to these fields, concerns have been raised regarding the relationship between electromagnetic fields and human health. Interest in the biological and health effects of intermediate frequency (IF) magnetic fields has grown recently because of the increase in public concern. In order to investigate whether IF magnetic fields have biological effects, we have developed a 20 kHz (IF) magnetic field exposure system for in vivo studies. The exposure facility was designed to study the biological effects of IF magnetic field on laboratory animals. The facility consists of a 9 m x 9 m x 5 m high room containing seven separate rooms including a 5.3 m x 4.5 m x 3 m high specific-pathogen free exposure room. The dimensions of the exposure system are 1.6 m x 1.6 m x 1.616 m high located inside this exposure room. The system is designed to provide magnetic fields up to 200 microT at 20 kHz with the uniformity within +/-5% over the space occupied by animals. After constructing the facility, performance tests were carried out. As a result, it was confirmed that our facility met requirements for evaluation of the biological effects of IF magnetic field on small animal experiments. In this paper, the design, construction, and results of evaluation of an animal exposure facility for the in vivo biological effects of an IF magnetic field are described.     

A newly designed microspectrofluorometer for kinetic studies on protein crystals in combination with x-ray diffraction

We present a new design for a fluorescence microspectrophotometer for use in kinetic crystallography in combination with x-ray diffraction experiments. The FLUMIX device (Fluorescence spectroscopy to monitor intermediates in x-ray crystallography) is built for 0 degrees fluorescence detection, which has several advantages in comparison to a conventional fluorometer with 90 degrees design. Due to the reduced spatial requirements and the need for only one objective, the system is highly versatile, easy to handle, and can be used for many different applications. In combination with a conventional stereomicroscope, fluorescence measurements or reaction initiation can be performed directly in a hanging drop crystallization setup. The FLUMIX device can be combined with most x-ray sources, normally without the need of a specialized mechanical support. As a biological model system, we have used H-Ras p21 with an artificially introduced photo-labile GTP precursor (caged GTP) and a covalently attached fluorophore (IANBD amide). Using the FLUMIX system, detailed information about the state of photolyzed crystals of the modified H-Ras p21 (p21(mod)) could be obtained. Measurements in combination with a synchrotron beamline showed significant fluorescence changes in p21(mod) crystals even within a few seconds of x-ray exposure at 100 K.     

Semisynthetic and newly designed derivatives based on natural chemical scaffolds: moving beyond natural products to fight Trypanosoma cruzi

Phytochemistry Reviews - Secondary metabolites obtained from natural sources are medicinally relevant molecules. About one-third of all FDA-approved drugs are derived from or based on natural...     

Linkers designed to intercalate the double helix greatly facilitate DNA alkylation by triplex-forming oligonucleotides carrying a cyclopropapyrroloindole reactive moiety.

Triplex-forming oligonucleotides (TFOs) bind sequence-specifically in the major groove of double-stranded DNA. Cyclopropapyrroloindole (CPI), the electrophilic moiety that comprises the reactive subunit of the antibiotic CC-1065, gives hybridization-triggered alkylation at the N-3 position of adenines when bound in the minor groove of double-stranded DNA. In order to attain TFO-directed targeting of CPI, we designed and tested linkers to 'thread' DNA from the major groove-bound TFO to the minor groove binding site of CPI. Placement of an aromatic ring in the linker significantly enhanced the site-directed reaction, possibly due to a 'threading' mechanism where the aromatic ring is intercalated. All of the linkers containing aromatic rings provided efficient alkylation of the duplex target. The linker containing an acridine ring system, the strongest intercalator in the series, gave a small but clearly detectable amount of non-TFO-specific alkylation. An equivalent-length linker without an aromatic ring was very inefficient in DNA target alkylation.     

KKKKPLFGLFFGLF: A cationic peptide designed to exert antibacterial activity

With 14 residues organized as two domains linked by a single proline, the de novo peptide called K4 was designed, using Antimicrobial Peptide Database, to exert antibacterial activity. The N-terminal domain is composed of four lysines enhancing membrane interactions, and the C-terminal domain is putatively folded into a hydrophobic α-helix. Following the synthesis, the purification and the structural checking, antibacterial assays revealed a strong activity against gram-positive and gram-negative bacteria including human pathogenic bacteria such as Staphylococcus aureus and some marine bacteria of the genus Vibrio. Scanning electron microscopy of Escherichia coli confirmed that K4 lyses bacterial cells. The cytotoxicity was tested against rabbit erythrocytes and chinese hamster ovary cells (CHO-K1). These tests revealed that K4 is non-toxic to mammalian cells for bacteriolytic concentrations. The peptide K4 could be a valuable candidate for future therapeutic applications.     

A functionalized cobalt(III) mixed-polypyridyl complex as a newly designed DNA molecular light switch

The ligand ODHIP (3,4-dihydroxyl-imidazo[4,5-f][1,10]phenanthroline) and its cobalt(III) complex [Co(bpy)(2)(ODHIP)](3+) were synthesized and characterized. Binding of this complex with calf thymus DNA has been investigated by spectroscopic methods and viscosity. The experimental results indicated that the complex bound to DNA by intercalation. In Tris buffer, the complex could emit relatively weak luminescence. After binding to DNA, the notable enhancement was observed. However, when the Cu(2+) was further added, the luminescence decreased gradually and disappeared after the equimolar concentrations of Cu(2+) was added, which exhibited the "off-on-off" properties of molecular light switch.     

A neural network designed to solve the N-Queens Problem

In this paper we discuss the Hopfield neural network designed to solve the N-Queens Problem (NQP). Our network exhibits good performance in escaping from local minima of energy surface of the problem. Only in approximately 1% of trials it settles in a false stable state (local minimum of energy). Extenive simulations indicate that the network is efficient and less sensitive to changes of its initial energy (potentials of neurons). Two strategies employed to achieve the solution and results of computer simulation are presented. Some theoretical remarks about convergence of the network are added.