Reduction of zygomatic arch fracture using a towel clip

The authors describe a simple technique for reducing zygomatic arch fractures with a towel clip. The orbital rim and zygomatic arch are outlined with a marking pen. The exact fracture site is then marked by palpation. The depressed fracture site is held with a towel clip and pulled outward gently. A clicking noise may be heard. The clip is then released. The contour of the zygomatic arch is compared with the other side. Using this technique the authors reduced 11 fractured zygomatic arches (arch only, displaced medially) in 11 patients and the results were satisfactory in all patients. The towel clip method is one procedure to reduce zygomatic arch fracture.

The thickness of the skull in Korean adults

New instrumentation and techniques for skeletal fixation have been developed in response to concerns regarding variability of the skull base and the calvaria. The fear of intracranial penetration has limited the use of internal or external fixation to the skull base and the calvaria. Despite potential clinical usefulness, limited anthropometric data have been reported on the skull base and the calvaria. The purpose of this study was to measure the average thickness of various points of the skull base and the calvaria of Korean adults. Fifty-one Korean adult skull bases and calvaria, which were cut 2 cm above the supraorbital margin anteriorly and 2 cm above the inion posteriorly, were measured in this study. Thickness of 13 clinically important points were measured with a Teclock GM-21 Calipergauge (Teclock Co., Tokyo, Japan). The mean thickness of the two opposite sides were compared using paired t-tests. They did not differ significantly from the others except for three points. Frontal bone A (located 1 cm above the supraorbital margin and 1.5 cm lateral to the midline) was 6.35 +/- 2.88 mm, frontal bone B (located at the midpoint of the frontal midpoint and the frontoparietal suture on the cut edge) was 5.24 +/- 1.50 mm, frontal bone C (located at the midpoint of the vertex and frontal bone B) was 6.63 +/- 1.77 mm, the pterion was 3.19 +/- 0.85 mm, the midpoint of the squamous temporal was 1.96 +/- 0.65 mm, parietal bone A (located 1.5 cm below the middle meningeal groove) was 3.99 +/- 1.11 mm; parietal bones B and C (divided at the distances between the frontoparietal suture and the occipital midpoint with a ratio of 1:3 and 2:3 respectively on the cut edge) were 4.71 +/- 1.06 mm and 5.35 +/- 0.91 mm respectively, occipital bone A (located 1.5 cm posterolateral from the foramen magnum) was 2.31 +/- 1.00 mm, occipital bone B (located 1.5 cm lateral to the midline and 0.5 cm above the inion) was 5.41 +/- 1.50 mm, occipital bone C (located occipital to the midpoint and 2 cm above the inion) was 8.2 +/- 1.67 mm, the orbital roof was 1.37 +/- 1.08 mm, and the orbital lateral wall was 2.25 +/- 1.06 mm. The data give practical information for determining the position and depth for safe and effective internal or external fixation during craniofacial procedures.

Alteration of the NAD+/NADH ratio in CHO cells by stable transfection with human cytosolic glycerol-3-phosphate dehydrogenase: resistance to oxidative stress

The intracellular level of the NAD+/NADH ratio plays a vital role in sustaining and coordinating the catabolic reaction of the cell, and reflects the redox state of cytosol. Antioxidants play a role to protect cytosol and membrane from free radicals. This role of antioxidants involves sustaining cell viability and the procedure is thought to be regulated by the equilibrium of the redox state of the cell. However, there is very little known about how the NAD+/NADH level is set and changed. To alter the ratio, human NAD-dependent glycerol-3-phosphate dehydrogenase (cGPDH) cDNA was transfected stably in CHO dhfr- cells. When compared to parental CHO cells, cGPDH activities of the transfected cells were increased 8-12 fold, but the NAD+/NADH ratio was decreased. Specific growth rate of the transfected cells was similar to or slight lower than that of wild type CHO cells. Cell viability of the stable transformants against H2O2 was increased without change of either catalase or glutathione peroxidase activity. However, the increase of cell viability was correlated with the decrease of NAD+/NADH ratio in transfectants. From these results, it is suggested that the overexpression of cGPDH changes the NAD+/NADH ratio toward a decrease, and by this change in the redox state the cell confers more resistance against H2O2.

Impact of nicotine on bone healing

A limited number of experimental animal studies and in vitro data confirm that nicotine impairs bone healing, diminishes osteoblast function, causes autogenous bone graft morbidity, and decreases graft biomechanical properties. Therefore, our long-term goal is to develop an effective therapy to reverse the adverse impact of nicotine from tobacco products. However, before accomplishing this goal, we had to develop an animal model. Our hypotheses were nicotine administration preceding and following autogenous bone grafting adversely affected autograft incorporation and depressed donor site healing in a characterized animal wound model. Hypothesis testing was accomplished in bilateral, 4-mm diameter parietal bone defects prepared in 60 Long-Evans rats (male, 35-day-old). A 4-mm diameter disk of donor bone was removed from the left parietal bone and placed in the contralateral defect. The donor site served as a spontaneously healing bone wound. The rats were partitioned equally among three doses of nicotine administered orally in the drinking water (12.5, 25, and 50 mg/L). For each dose, the duration and sequence of nicotine treatment followed four courses, including no nicotine and designated combinations of nicotine administration and abatement prior to and following osseous surgery. Experimental sites were recovered on 14 and 28 days postsurgery, responses quantitated, and data analyzed by analysis of variance and post hoc statistics (p < or = 0.05). We developed a convenient and effective osseous model, and the results validated our hypothesis that nicotine negatively impacts on bone healing.

Attachment of the deep temporal fascia to the zygomatic arch: an anatomic study

It is generally acknowledged that the superficial layer of the deep temporal fascia attaches to the lateral surface and its deep layer along the medial surface of the zygomatic arch. However, Ramírez asserts that the superficial and the deep layer of the deep temporal fascia fuse consistently approximately 1 cm above the upper ridge of the arch and attach to the outer surface of the arch, blending with the superficial fascia of the masseter muscle. In this study the authors clarify the precise anatomic relations between the fascia and the zygomatic arch. Coronal sections crossing the midpoint between the zygomaticotemporal suture and the tubercle of zygoma were observed grossly and histologically in 32 hemifaces from 16 Korean adult cadavers. This study demonstrates that the superficial and the deep layers of the deep temporal fascial fuse and insert onto the superior margin of the arch in 18 dissections (56%) and insert onto the superolateral surface in 14 dissections (44%). The contacting surface of the fused deep temporal fascia to the periosteum of the zygomatic arch is less than 2 mm. The following route is safer and is recommended for reaching the zygomatic arch region: Just above the split of the deep temporal fascia, a dissection is carried through the deep temporal fasica, continuing downward to the superior margin of the arch along the undersurface of the fascia. At this spot the periosteum of the arch is dissected.

Impact of nicotine on bone healing

A limited number of experimental animal studies and in vitro data confirm that nicotine impairs bone healing, diminishes osteoblast function, causes autogenous bone graft morbidity, and decreases graft biomechanical properties. Therefore, our long-term goal is to develop an effective therapy to reverse the adverse impact of nicotine from tobacco products. However, before accomplishing this goal, we had to develop an animal model. Our hypotheses were nicotine administration preceding and following autogenous bone grafting adversely affected autograft incorporation and depressed donor site healing in a characterized animal wound model. Hypothesis testing was accomplished in bilateral, 4-mm diameter parietal bone defects prepared in 60 Long-Evans rats (male, 35-day-old). A 4-mm diameter disk of donor bone was removed from the left parietal bone and placed in the contralateral defect. The donor site served as a spontaneously healing bone wound. The rats were partitioned equally among three doses of nicotine administered orally in the drinking water (12.5, 25, and 50 mg/L). For each dose, the duration and sequence of nicotine treatment followed four courses, including no nicotine and designated combinations of nicotine administration and abatement prior to and following osseous surgery. Experimental sites were recovered on 14 and 28 days postsurgery, responses quantitated, and data analyzed by analysis of variance and post hoc statistics (p < or = 0.05). We developed a convenient and effective osseous model, and the results validated our hypothesis that nicotine negatively impacts on bone healing.

Bone morphogenetic proteins: an update on basic biology and clinical relevance

The regeneration of bone is a remarkable, complex physiological process, and BMPs are a formidable clinical tool to promote its regeneration. By defining roles played by BMPs in developmental biology and bone regeneration, significant progress has been made to identify cell-signaling molecules and their regulators. For example, the regulators of BMPs that include noggin, chordin, cerberus, dan, and gremlin may be harnessed as therapies to offset calcification encountered after total hip arthroplasties. Furthermore, exploiting BMPs and Smads may generate new therapeutic options for bone repair. Another compelling clinical consideration is the trans-acting factor osteoblast-specific factor-2, which can promote osteoblast differentiation. Moreover, the affiliation of osteoblast-specific factor-2 with heritable disorders merits exploration. A recognized daunting challenge includes a carrier/delivery system for the powerful morphogenetic therapeutic tools, as well as osteoprogenitor cells and intracellular transduction and transcriptional factors. In addition, the long-term effects of administering superphysiological doses of rhBMPs to patients must be assessed systematically. A new generation carrier/delivery system may be the answer to offset dosing liabilities as well as to provide residence for exogenous, BMP-receptive osteoprogenitor cells (111,112). The areas highlighted in this review offer fertile territory for thought and research to develop rational clinical treatments to promote bone regeneration and to understand some of the biological roles of BMPs.

Surgical anatomy of the orbit of Korean adults

When operating in and around the orbit, the key to a successful result is precise anatomical localization. However, there is no precise study about the localization of vital orbital structures from reliable periorbital bony anatomy of the Korean adult. This study was constructed to give pertinent anatomical measurements to which the plastic and maxillofacial surgeon may refer. The 82 orbits obtained from 41 skulls of adult Koreans were measured with Vernier calipers and Marshac calipers. Superiorly, the supraorbital fissure was 40.0 +/- 2.5 mm from the supraorbital notch. Medially, the posterior ethmoidal foramen was 31.7 +/- 3.0 mm from the anterior lacrimal crest. Inferiorly, the infraorbital fissure where the infraorbital groove started was 26.4 +/- 2.6 mm from the infraorbital foramen. Laterally, the supraorbital fissure was 34.3 +/- 2.7 mm from the frontozygomatic suture. These distances are suggested as appropriate safe distances from each periorbital bony landmark. Dissection beyond that distance should be done with great caution.

An anatomical study of the junction of the orbital septum and the levator aponeurosis in Orientals

The anatomical relationships of the orbital septum and levator aponeurosis has been studied in 40 eyelids subjected to blepharoplasty and corrective ptosis surgery by dissection in 10 cadavers and in histological sections. The orbital septum originates from the arcus marginalis of the frontal bone and consists of two layers. The whitish outer (superficial) layer, containing vertically running vessels, descends just inside the orbicularis oculi muscle to interdigitate with the levator aponeurosis with loose connective tissue, then disperses inferiorly. The inner (deep) layer follows the superficial one initially, then reflects at the levator aponeurosis and continues posteriorly with the levator sheath. We reconfirmed Whitnall's original description that the levator sheath thickens to form the superior transverse ligament runs continuously inferiorly anterior to the levator aponeurosis and forms the inner layer of the orbital septum. This detailed anatomical analysis should assist in performing upper eyelid surgery such as the Oriental double fold operation or levator resection.

Appendiceal CT in 140 cases. Diagnostic criteria for acute and necrotizing appendicitis

Computed tomography (CT) was performed in 140 patients with suspected acute appendicitis. Thin collimation (5 mm), intravenous contrast enhancement, 1-second scan times, and supplementary cecal air insufflation were emphasized. CT accuracy was 98% overall (137/140), and 99% in the 124 cases with early surgery. Necrotizing appendicitis was diagnosed by CT with 86% accuracy and 90% positive predictive value.

Distribution of hairs and sweat glands on the bodies of Korean adults: a morphometric study

A morphometric study was made of the number of sweat glands and hairs per square centimeter of skin on different body regions of Korean adults. For this purpose, samples of skin from 30 body regions were obtained by punch biopsy from 74 cadavers of Korean adults. Serial transverse sections that extended through the papillary layer of the dermis were prepared in each case and subjected to routine histological staining. Sections of skin were examined under low magnification and the sweat ducts and hair follicles in each section were counted and recorded in terms of the number per square centimeter of skin. Arithmetic means and standard deviations for each region were also obtained for comparison of the densities of distribution. The soles (male) and the palms (female) were the regions of most densely distributed sweat glands while the mammary area in both sexes was the region of lowest density. Hairs were distributed most densely in the buccal region in males and on the mental (chin) region in females. The region of lowest density of hairs was the dorsum of the middle phalanx of the fingers in both sexes. Seven regions of the body exhibited significant sexual dimorphism in terms of the density of sweat glands while only four regions showed significant sexual dimorphism in terms of the density of hairs. Hairs appeared to be more densely distributed in the buccal regions of females than of males. However, the density of hairs in the dermis was not always proportional to the density of visible hairs.

A thickness map of iliac bone of Korean adults

The iliac bone is one of the most common donor sites for bone graft. Despite such potential and clinical usefulness, the anthropometric data on the iliac bone are lacking. The purpose of this study is to construct a thickness map that provides the mean iliac bone thickness of its various points and their differences. We studied 58 hip bones (from 23 males and 35 females) from Korean adults. We measured the iliac bone thickness at 26 points, which were positioned at regular intervals on each given iliac bone, using a Techlock GM 21 caliper gauge. The mean thickness of each measuring point of the male and the female, and of the right and the left, was compared with each other through paired t-test; the measurements did not differ significantly. From the anteriorposterior perspective, the region between anterior superior iliac spine (ASIS) and iliac tubercle was relatively thick. However, it became progressively thinner before it reached the sacroiliac articulation. It became thicker again toward the posterior superior iliac spine (PSIS), the thickest area. From the superoinferior perspective of superior iliac crest and inferior acetabulum, the thickness became inferiorly thinner in the anterior part between ASIS and iliac tuberosity. However, in the posterior part between the sacroiliac joint and PSIS, there was no significant difference of thickness. We hope that our thickness map can serve as a practical guide to the choice of an ideal site of the iliac bone for bone graft to obtain desired thickness.

Thickness map of parietal bone in Korean adults

The parietal bone remains the most common donor site for a bone graft in treating facial bone fractures, especially those involving orbital walls. Despite this potential clinical usefulness, anthropometric data on the parietal bone is lacking. Only one Korean and a few foreign studies report on its thickness, measured at two and three points of each of two parietal bones in a given subject, respectively. These studies, however, fall short of offering enough information for locating the optimal harvest point of the parietal bone for bone grafting. This study was thus aimed at constructing a thickness map that provides the mean parietal bone thickness at various points and determines the difference between them. Eighty-eight parietal bones were obtained from 44 Korean adult skulls for this study. Parietal bone thickness was measured at 15 points, spaced at regular intervals on each parietal bone of a given skull, using a Techlock GM 21 caliper gauge. The mean bone thickness at each of the 15 points of the bone and at the corresponding points of the opposite parietal bone was obtained in all skulls studied. The mean thickness at each point of measurement on two opposite parietal bones was compared using the paired Student's t test. Mean thickness did not differ significantly. The thickness in the same bone varied widely depending on the points of measurement. The thickest part, the posteromedial region of the parietal bone near the lambda, was 6.67 +/- 1.41 mm (mean +/- standard deviation [SD]) thick, and it became thinner toward the diagonal (anterolateral) direction, to the thinnest part, 4.73 +/- 1.19 mm (mean +/- SD) thick, near the pterion. It is hoped that our thickness map can serve as a practical guide for choosing an ideal site on the parietal bone for a bone graft of desired thickness.

Intracellular distribution of selenium and the growth of mammary cells in culture

Retention of Se in CMT-13 cells increased with an increase in the concentration of selenite in the incubation medium, the duration of exposure, and the density of the culture. The enhanced toxicity of selenite coincided with a proportional increase in Se in both the cytoplasm and nucleus. About 90% of the accumulated Se was isolated with cytoplasmic macromolecules. Increased nuclear Se retention correlated with increased cytoplasmic Se retention. Greater quantities of cytosolic Se-containing proteins (74, 55, 41, 34, and 28 kDa) and a nuclear Se-containing protein (56 kDa) were detected as the quantity of Se within CMT-13 cells increased. These findings suggest that cellular retention and distribution of Se are determinants of the degree of cellular growth inhibition caused by this trace element.

Identification and characterization of a coronavirus packaging signal

Previously, a mouse hepatitis virus (MHV) genomic sequence necessary for defective interfering (DI) RNA packaging into MHV particles (packaging signal) was mapped to within a region of 1,480 nucleotides in the MHV polymerase gene by comparison of two DI RNAs. One of these, DIssF, is 3.6 kb in size and exhibits efficient packaging, whereas the other, DIssE, which is 2.3 kb, does not. For more precise mapping, a series of mutant DIssF RNAs with deletions within this 1,480-nucleotide region were constructed. After transfection of in vitro-synthesized mutant DI RNA in MHV-infected cells, the virus product was passaged several times. The efficiency of DI RNA packaging into MHV virions was then estimated by viral homologous interference activity and by analysis of intracellular virus-specific RNAs and virion RNA. The results indicated that an area of 190 nucleotides was necessary for packaging. A computer-generated secondary structural analysis of the A59 and JHM strains of MHV demonstrated that within this 190-nucleotide region a stable stem-loop of 69 nucleotides was common between the two viruses. A DIssE-derived DI DNA which had these 69 nucleotides inserted into the DIssE sequence demonstrated efficient DI RNA packaging. Site-directed mutagenic analysis showed that of these 69 nucleotides, the minimum sequence of the packaging signal was 61 nucleotides and that destruction of the secondary structure abolished packaging ability. These studies demonstrated that an MHV packaging signal was present within the 61 nucleotides, which are located on MHV genomic RNA 1,381 to 1,441 nucleotides upstream of the 3' end of gene 1.

Primary amino acid sequence of alpha-trichosanthin and molecular models for abrin A-chain and alpha-trichosanthin

Ricin A-chain, abrin A-chain, and alpha-trichosanthin are members of a larger group of proteins called ribosome-inactivating proteins. These proteins all function to catalytically inactivate eukaryotic 60 S ribosomal subunits leading to rapid shutdown of protein synthesis. They are homologous in sequence and are probably evolutionarily related. We have determined the complete primary amino acid sequence of alpha-trichosanthin and have found it to be homologous, as expected, to that of abrin A-chain and ricin A-chain. A crystal structure for ricin, which includes ricin A-chain and ricin B-chain, has been determined from x-ray diffraction data. Based on the sequence homologies of these proteins, we fit the primary sequences of abrin A-chain and alpha-trichosanthin to the backbone structure for ricin A-chain and have generated energy-minimized molecular models for them. These models should prove useful in studying the structural-functional relationships of these proteins in particular and of the class in general.

Dynamic Electrical and Electromechanical Properties of Carbon-Black Loaded Rubber

1. Low-frequency resistance can be dominated by contacts. It was found that silver paint contacts were roughly equivalent to metal contacts bonded during vulcanization. 2. Three electrical regimes are clearly evident, determined by loading: dielectric, percolation, and conducting. 3. Resistance and dielectric constant dispersion for loading above 30 phr agree with Kawamoto's model. 4. Each carbon-black loading results in a distinctive dispersion signature. 5. Dynamic conductivity can be used to delineate persistent and transient carbon-black-structure changes versus composition, DSA, frequency, and potentially other parameters (temperature, stress waveform, etc.). 6. The remaining conductive network during stress is represented by gmin; Δg is determined by network fracture and reformation; gmin−gα is proportional to the amount of remaining transient structure; g0−gα is proportional to the total transient structure; normalized conductivity Z is the remaining-to-total transient-structure ratio. 7. The Δgm=0.525(g0−gα) relation indicates that maximum reformation occurs when approximately half the transient structure is broken down and confirms the correlation between conductivity parameters and transient carbon-black structure.

Coronary blood flow and thallium 201 uptake in rejecting rat heart transplantations

The effects of rejection on coronary flow (CAF) in heart allografts are unclear, although previous evidence with cardiac imaging agents indicates impaired flow during advanced rejection. The purpose of this study was to measure CAF in heterotopically placed heart grafts. Lewis rats (LEW) received grafts from either syngeneic Lewis rats (LEW/LEW group) or allogeneic ACI rats (ACI/LEW group). CAF was measured in both the transplanted and native hearts with radiolabeled microspheres. Rejection was measured histologically (grades 0 [absent] to 4+ [severe]). In addition systemic blood pressure and cardiac outputs of the native hearts were determined with microspheres. Different animals were studied during relatively early (4 days) and late (6 days) rejection. Among the 4-day animals a cyclosporine-treated group was included (ACI/LEW CyA). In 6-day rats CAF in allografts was lower (0.56 +/- .06 ml/gm/min) compared with syngeneic grafts (1.72 +/- 0.4 ml/gm/min) (p less than 0.05). The CAF in the native hearts did not differ significantly but was higher than in the grafts in both groups. Heart rates were reduced in allografts (p less than 0.05). It is interesting that arterial pressure and cardiac output were significantly lower in animals bearing allogeneic than syngeneic grafts. In rats studied at 4 days graft CAF was lower than in the native heart in both the LEW/LEW and ACI/LEW groups, but there was no significant difference in behavior between groups. The same was true for a cyclosporine-treated group. Graft heart rates were similar in all 4-day rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium regulation in vascular smooth muscle contractility

The contractile activity of vascular smooth muscle is regulated by control over the cytoplasmic calcium concentration. The intracellular calcium receptor is calmodulin, which, through stimulation of myosin light chain kinase, can activate 2 different contractile states. The calcium is supplied from the sarcoplasmic reticulum and the extracellular space; a minor component is supplied from the inner surface of the plasmalemma. The main intracellular messenger responsible for the transduction of receptor occupation and calcium release from the sarcoplasmic reticulum is IP3 and, to a lesser extent, calcium itself. The superficial location of the sarcoplasmic reticulum in vascular smooth muscle makes it the logical area for control of calcium entry due to calcium leak or through either or both types of calcium channel. The sarcoplasmic reticulum, therefore, acts as a "superficial calcium buffer barrier" and is probably the major system controlling free cytoplasmic calcium concentration in vascular smooth muscle.