A Mental Space Similarity Group Model of Shape Constancy

A group model of mental transformations based on the geometric model of P. B. Yale (1968, Geometry and symmetry, Holden-Day, San Francisco) was constructed for form recognition. The model consisted of nine characteristic subgroups of the similarity group in Euclidean space. With these subgroups, six series were formed, representing six visual paths for form recognition. Each series involved five characteristic subgroups. Six subframes were associated with nine characteristic subgroups in the model. These subframes were shape (angle measure), the sense, size (volume), verticality, uprightness, and position. The model was validated by an experiment, using reaction time as the behavior index. Since shape is the common invariant property of all subgroups of the similarity group, angle measure was not included in ordering of subframes. The findings show that the preservation of uprightness of a form provides the best condition for form recognition, followed by the preservation of sense and verticality of a form. While the effect of position is not strong, size has the weakest influence on space form recognition. Copyright 1999 Academic Press.

Characterization of dental follicle cells in developing mouse molar

Dental follicle has been implicated as the origin of alveolar bone, cementum and periodontal ligament, but there is no direct evidence of their cellular lineage. The present pilot study was designed to characterize the phenotype of cultured cells obtained from the dental follicle of neonatal mouse molars. Developing mandibular molars from 6-day-old CD-1 mice were subjected to 1% trypsin in Hank's balanced salt solution. After trypsinization, the dental follicle was enucleated from the tooth germ and separated from the associated epithelial root sheath. Pure dental follicle tissue was cultured in alpha-minimal essential medium containing 10% fetal bovine serum and antibiotics. The nature of the cultured follicle cells was determined in situ by immunocytochemical staining for type I and III collagen, fibronectin, and alkaline phosphatase expression. Earlier phenotypic markers for mineralization such as bone sialoprotein and osteopontin were also examined by in situ hybridization of matched molar tissues. The extracellular matrix proteins (such as type I collagen and fibronectin) were moderately expressed cytochemically. However, type III collagen was strongly stained. Gene expression of bone sialoprotein and osteopontin was detected in sections of mouse molars of similar age. The ALPase activity showed moderate to strong intensity in these primary cultured cells and responded to 1,25(OH)2 vitamin D3 treatment. Cytokeratin stains were not noted in these cells. In conclusion, the 6-day-old dental follicle cells exhibit partial characteristics of a mineralized tissue-forming phenotype even though the expression of osteopontin, type I collagen and fibronectin was low at this stage.

Determination of fatty acids in vegetable oil by reversed-phase liquid chromatography with fluorescence detection

The effect of temperature and organic solvent composition (acetonitrile and methanol) on the reversed-phase separation of coumarin-derivatized fatty acids according to their carbon number (C14 to C22), the degree of unsaturation, as well as cis/trans (C18:1 c/t, C18:2 cc/tt, C18:3 ccc/ttt) configuration was investigated to find out the effective separation condition. Based on the linear plots of the logarithm of the capacity factor of saturated fatty acids versus their carbon number, the equivalent chain length (ECL) of unsaturated fatty acids was calculated. The ECL values were found to be significantly altered and the differentiation between cis and trans fatty acids was increased when either the temperature or organic solvent composition was decreased. These results generally led to a better resolution at the expense of separation time. A ternary gradient composed of water, acetonitrile, and methanol was then developed to elute the solutes at 55 degrees C within a separation time of 40 min with a minimum resolution of 1.0 for the worst pair. This method was demonstrated to resolve the fatty acids in a vegetable shortening.

The response of cAMP and DNA synthesis in rat osteosarcoma cells to mechanically deformed culture dishes

The purpose of this research was to document the biochemical response of rat osteosarcoma cells (ROS 17/2.8) to mechanical stress in vitro. The influence of mechanical stress on ROS 17/2.8 cells was studied using a stress application device. Briefly, the device was fabricated by bonding an orthodontic expansion screw outside the bottom of a plastic culture dish with self-curing acrylic resin. Irreversible deformation of the culture dish was produced by activating an expansion screw. The resulting mechanical stress was transferred to the cells which attached to the culture dish. The response in terms of cyclic adenosine monophosphate (cAMP) of ROS 17/2.8 cells to mechanical stress was measured using a competitive protein-binding method. The effect of mechanical stress on cellular growth was assessed through the incorporation of 3H-thymidine after different periods of mechanical stress application. The results revealed that mechanical stress could increase the production of cAMP in ROS 17/2.8 cells at an early phase after stress stimulation. This change in the cAMP level was dependent on the duration of stress application, and the maximal response occurred when the mechanical stress was applied for one hour. Although the cellular incorporation of 3H-thymidine decreased 40-60% in ROS 17/2.8 cells subjected to mechanical stress for 1 hour, this reaction recovered from the inhibition effect to 80-85% of the baseline when the mechanical stress lasted for 24 hours. The observations in this study indicate that mechanical stress stimulates the production of cAMP and inhibits the 3H-thymidine incorporation of ROS 17/2.8 cells at an early phase of stress application.

Microbial decolorization of azo dyes by Proteus mirabilis

A bacterium identified as Proteus mirabilis was isolated from acclimated sludge from a dyeing wastewater treatment plant. This strain rapidly decolorized a deep red azo dye solution (RED RBN). Features of the decolorizing process related to biodegradation and biosorption were also studied. Although P. mirabilis displayed good growth in shake culture, color removal was best in anoxic static cultures. For color removal, the optimal pH and temperature were 6.5-7.5 and 30-35 degrees C, respectively. The organism exhibited a remarkable color removal capability, even at a high concentration of azo dye. More than 95% of azo dye was reduced within 20 h at a dye concentration of 1.0 g L-1. Decolorization appears to proceed primarily by enzymatic reduction associated with a minor portion, 13-17%, of biosorption to inactivated microbial cells.

Urine free beta-human chorionic gonadotropin levels between 14 and 21 weeks of gestation in Taiwanese pregnancies

BACKGROUND

The purpose of this study was to determine the reference range of maternal urine free beta-human chorionic gonadotropin (beta -hCG) concentrations between 14 and 21 weeks of gestation.

METHODS

We measured the concentrations of urine free beta -hCG from 268 healthy singleton Taiwanese pregnancies between 14 and 21 weeks of gestation. Results were corrected for creatinine (Cr) concentration and converted to the multiple of the median (MOM) level for the appropriate gestation. Gestational ages of all cases were determined using ultrasound dating.

RESULTS

The median levels of urine free beta -hCG and free beta-hCG/Cr had a downward trend in association with the increasing gestation age. The median, 5th, 10th, 90th and 95th centiles of free beta- hCG/Cr MOM values were 1.02, 0.20, 0.25, 2.32 and 3.38 MOM, respectively. Urine free beta- hCG/Cr MOM values showed a log Gaussian distribution with the mean and standard deviation (SD) distribution of -0.0657 and 0.3792, respectively.

CONCLUSION

To allow for differences in free beta -hCG/Cr median values at various ages of gestation, establishment of the reference range is essential for further development of maternal urine screening for Down syndrome.

Mathematical models for motile bacterial transport in cylindrical tubes

Mathematical models considering motile bacterial transport within a geometrically restrictive cylindrical tube were developed. Two macroscopic transport parameters, the random motility coefficient as a self-diffusion coefficient of the cell population and the chemotactic velocity as a chemical-induced velocity, were derived. The three-dimensional cell balance equation was reduced to forms similar to Segel's one-dimensional phenomenological cell balance equations with additional modifications for bacteria-wall interactions. Two conceptually different approaches accounting for such interactions were presented. The first approach parallels treatments in the gas kinetic theory by viewing bacterial interactions with walls as collisions and subsequent diffusive/specular reflections, which led to the Bosanquet formula for the bacterial diffusion coefficient. Based on the experimental observation that bacterial swimming motion is guided by a straight tube, the second approach considered modifications in the bacterial swimming orientation as a consequence of various long-range interactions with the tube surface. A phenomenological turning model capable of aligning bacterial motion along a tube axis was proposed. The model predicts that under the geometrical restriction of a small cylindrical tube, the macroscopic bacterial transport resulting from the proposed turning model can exhibit behavior that ranges from dimensionally reduced diffusion to pure wave propagation, depending on the influence of the tube diameter on the reversal probability in the bacterial swimming motion. Our theoretical model provides explicit equations that explain how such a transition can occur. The predicted results were then qualitatively compared with experimental data from the literature. As a preliminary comparison, we concluded that bacterial transport in cylindrical tubes of diameter 10 micrometers remains in the mode of a dimensionally reduced diffusion, and shifts to a wave motion when the tube diameter decreases to 6 micrometers.

Ultrasonography for inguinal hernias in boys

BACKGROUND/PURPOSE

History taking and physical examination alone no longer meet the surgeon's need in the diagnosis of inguinal hernia. Ultrasonography (US) provides a good and safe diagnostic tool for inguinal hernias in boys.

METHODS

From 1995 to 1997, 244 boys with inguinal hernias (41 bilateral and 203 unilateral), received preoperative US on both groins to confirm the diagnosis. Those with positive US findings, such as viscera or fluid in inguinal canal or widening of the internal inguinal ring, underwent surgery.

RESULTS

The accuracy of diagnosis with US and clinical assessment were 97.9% and 84%, respectively. More than 95% of widening of internal inguinal rings (>4 mm) proved to be hernias. There were two direct inguinal hernias and two femoral hernias, which were misdiagnosed by clinical examination, but proved to be diagnosed correctly by US.

CONCLUSIONS

US serves as a noninvasive and highly accurate diagnostic tool for inguinal hernias in boys. Using 4 mm as the upper limit of the normal diameter of the internal inguinal ring, an occult inguinal hernia can be easily detected before surgery.

The global turning probability density function for motile bacteria and its applications

The angular turning probability density distribution for motile bacteria is usually measured in local coordinates and is therefore inconvenient for global analyses of the chemotactic bacterial migration. In this paper we present analytical derivations that convert the local angular turning probability density distribution into a global one. The explicit expression of a reduced global turning probability density function for motile bacteria was derived and its relevant properties were investigated. Depending on the angle variable being intergrated and the integration range, three types of cosine moments were separately defined and studied. Some statistical indices and parameters such as the directional persistence, persistence number, and one-dimensional reversal probability were found to be embedded in the various moments of the reduced global turning probability density function. Applications of the reduced global turning probability and its integrated moments to a three-dimensional cell balance equation in an axisymmetric system were also discussed.

Up-regulation of alpha1D Ca2+ channel subunit mRNA expression in the hippocampus of aged F344 rats

There is growing evidence that alterations in calcium (Ca2+) homeostasis may play a role in processes of brain aging and neurodegeneration. There also is evidence that some of the altered Ca2+ homeostasis in hippocampal neurons may arise from an increased density of L-type voltage sensitive Ca2+ channels (L-VSCC). In the present studies, we tested the possibility that previously observed increases in functional L-VSCC with aging might be related to up-regulated gene/mRNA expression for Ca2+ channel subunits. A significant aging-related increase in mRNA content for the alpha1D subunit of the L-type VSCC was observed in hippocampus of aged F344 rats (25 months old) relative to young (4 months old) and middle-aged animals (13 months old), as assessed by both in situ hybridization analyses (densitometry and grain density) and ribonuclease protection assay (RPA). In RPA analyses, the alpha1C subunit mRNA also showed a significant increase in 25-month-old rats. No age changes were seen in mRNA for the beta1b subunit of VSCC or for GAPDH, a standard control. The clearest increases in alpha1D mRNA expression were observed in subfield CA1, with little or no change seen in dentate gyrus. Although these results alone do not demonstrate that mRNA/gene expression changes contribute directly to changes in functional Ca2+ channels, they clearly fulfill an important prediction of that hypothesis. Therefore, these studies may have important implications for the role of gene expression in aging-dependent alterations in brain Ca2+ homeostasis.

Simultaneous measurement of blood and brain microdialysates of granisetron in rat by high-performance liquid chromatography with fluorescence detection

Simultaneous microdialysis probes in the blood and brain and sensitive high-performance liquid chromatography with fluorescence detection were used to examine the granisetron concentration in the jugular vein and frontal cortex of rats after drug administration. Two microdialysis probes were inserted into the right jugular vein and frontal cortex of male Sprague-Dawley rats to which granisetron (6 mg/kg, i.v.) had been administered. Dialysates were automatically collected using a microfraction collector. Samples were eluted with a mobile phase containing 25 mM acetate buffer (pH 4.8)-acetonitrile (72:28, v/v). Excitation and emission wavelengths were set at 305 and 360 nm, respectively, on a scanning fluorescence detector. The limit of quantification for granisetron was 0.5 ng/ml. The in vitro recovery of granisetron was 29.7+/-1.2% (n=6) for the jugular vein microdialysis probe and 6.1+/-0.5% (n=6) for the frontal cortex microdialysis probe. The increasing brain/blood concentration ratio of granisetron suggests that granisetron penetrates the blood-brain barrier.

Temporal and spatial expression of erbB4 in ectodermal and mesenchymal cells during primary palatogenesis in noncleft and cleft strains of mice

Primary palatogenesis in mice is similar to that in humans, and spontaneous cleft lip appears to be multifactorially determined in both. Binding of a ligand to erbB4 has been shown to stimulate the receptor's protein kinase activity, which subsequently stimulates a signal-transduction cascade leading to cell growth and differentiation, and to morphogenesis during development. In this study, an immunohistochemical technique was used to investigate the temporal and spatial expression of erbB4 in the primary palate of cleft (A/WySn) and noncleft strains of mice (BALB/cBy). Positive staining of erbB4 was found in ectodermal and mesenchymal cells of facial prominences before the primary palate formation stage (day 10, hour 20) in both strains. During the primary palate formation stage (day 11, hour 20), positive staining of erbB4 was found in the ectodermal and mesenchymal cells of the facial prominences of the noncleft strain, but not in those of the cleft strain. These results suggest erbB4 expression may be associated with normal primary palatogenesis of mice and, conversely, cleft lip may be associated with a deficiency of erbB4 expression during primary palate formation in mice.

Calcium channel density and hippocampal cell death with age in long-term culture

The expression of voltage-gated calcium (Ca2+) channel activity in brain cells is known to be important for several aspects of neuronal development. In addition, excessive Ca2+ influx has been linked clearly to neurotoxicity both in vivo and in vitro; however, the temporal relationship between the development of Ca2+ channel activity and neuronal survival is not understood. Over a period spanning 28 d in vitro, progressive increases in high voltage-activated whole-cell Ca2+ current and L-type Ca2+ channel activity were observed in cultured hippocampal neurons. On the basis of single-channel analyses, these increases seem to arise in part from a greater density of functionally available L-type Ca2+ channels. An increase in mRNA for the alpha1 subunit of L-type Ca2+ channels occurred over a similar time course, which suggests that a change in gene expression may underlie the increased channel density. Parallel studies showed that hippocampal neuronal survival over 28 d was inversely related to increasing Ca2+ current density. Chronic treatment of hippocampal neurons with the L-type Ca2+ channel antagonist nimodipine significantly enhanced survival. Together, these results suggest that age-dependent increases in the density of Ca2+ channels might contribute significantly to declining viability of hippocampal neurons. The results also are analogous to patterns seen in neurons of aged animals and therefore raise the possibility that long-term primary neuronal culture could serve as a model for some aspects of aging changes in hippocampal Ca2+ channel function.

Effects of glucose on placental hormones in the human term placenta in vitro

Glucose intake during pregnancy results in a decrease in endogenous insulin-like growth factor binding protein-1 (IGFBP-1). However, the exact role of glucose on placental secretion of IGFBP-1 is unclear. This study was designed to investigate the direct effects of glucose on the production of IGFBP-1 and other placental hormones, using an isolated placental preparation. Using the dual recirculating perfusion system for an isolated human placenta lobule, a total of 43 experiments were performed over a duration of 6 hours. Twenty placentae were perfused with a medium containing 141 +/- 10 mg/dL (7.83 +/- 0.56 mmol/L) glucose (group I) and 23 placentae with 242 +/- 12 mg/dL (13.43 +/- 0.67 mmol/L) glucose (group II). Levels of insulin, glucose, lactate, insulin-like growth factor (IGF-I), IGFBP-1, human placental lactogen (hPL) and beta-human chorionic gonadotropin (beta-hCG) were measured at 30 minute intervals during perfusion. Insulin and IGF-I were barely detectable in the perfusates and their levels were not modulated by glucose. IGFBP-1 was predominantly detected in the maternal rather than the fetal compartment of the placental circulation. Glucose increased the levels of IGFBP-1 in the maternal circulation in groups I and II during the first two hours of perfusion (188 +/- 58% and 193 +/- 31%, respectively). However, during the subsequent 4 hour period, the increase in IGFBP-1 concentration was significantly higher in group II (926 +/- 427%) than in group I (428 +/- 216%) (p < 0.05). There was no difference in the levels of hPL or beta-hCG between the two groups in the maternal circulation. Thus, glucose stimulates the production of IGFBP-1 in the maternal circulation of a placenta in vitro. This increase in IGFBP-1 by glucose in vitro, as opposed to the decrease of IGFBP-1 in vivo, may be due to a lack of circulatory maternal insulin in the isolated placental preparation. These results also suggest that there may be a functional barrier within the placenta that prevents an increase in the level of IGFBP-1 in the fetal circulation.

Functional connectivity of the transected brachial plexus after intercostal neurotization in monkeys

Microsurgical reconstructions of brachial plexuses were performed on twelve monkeys by using ipsilateral intercostal nerves (T3-9). Reinnervation in individual nerves was evaluated monthly by observations of neuromuscular and electromyographic improvements. The electromyographic studies revealed reappearance of motor unit potentials. According to a motor scale ranging from 0 to 4, the mean muscle power 6 months after operation improved to 2.75 in the deltoid muscles, 2 in the biceps muscles, 1.22 in the triceps muscles, 1.13 in the flexor carpi radialis muscles, and 1.6 in the intrinsic muscles of the hands. Retrograde transport of horseradish peroxidase (HRP) from the neuromuscular junctions of the reconstructed musculocutaneous nerves 6 months after complete brachial plexus lesion in four animals demonstrated HRP-labeled neurons in the anterior horns, spinal ganglia and sympathetic ganglia of the thoracic spinal cords. It suggested that the regenerated afferent and efferent circuits in the thoracic cords innervating the transected brachial plexuses were able to generate the movements in the paralyzed upper limbs. However, as evidenced by the behavior patterns and the fact that retrograde-labeled neurons were all found in the thoracic cords, the novel movements observed in the reconstructed brachial plexuses were in synchrony with respiration. These results suggested that the plasticity of central neural networks is limited between two widely separated areas, such as between the midcervical and midthoracic motor cortical areas in the present studies, and therefore, the efforts to reconstruct neural networks, both centrally and peripherally, should aim at rebuilding situations as nearly to the original status as possible.

The importance of determination of jaw position in orthodontic diagnosis and treatment planning for adult patients

The basic data needed for orthodontic diagnosis and treatment planning include color prints of soft tissue facial profile, intraoral dental arches, and occlusion; cephalometric and panoramic radiographs; and dental casts. Hand-wrist and TMJ radiographs are also necessary in some circumstances. If orthodontic diagnosis and treatment plans are made only from the dental alignments and occlusion from the static or hand-assembled dental casts, the diagnosis and treatment planning made may be wrong in some cases. Clinically, it is necessary to find the centric relation of the lower jaw and to transfer the jaw relationship to the articulator. Correct diagnosis and orthodontic treatment planning may then be made from the findings of the occlusal relationship from the articulator accompanied with the information on skeletal age and craniofacial characteristics from the hand-wrist and cephalometric radiographs. Four clinical cases have been presented to demonstrate the importance of determination of jaw position in orthodontic diagnosis and treatment planning in adult patients.

Cytotoxic effects of anthrax lethal toxin on macrophage-like cell line J774A.1

The cytotoxic effects of anthrax lethal toxin purified from an avirulent strain were examined on mouse macrophage-like J774A.1 cells. Cell death induced by high concentration of purified lethal toxin had the characteristics of necrosis. At lower concentrations, the toxin caused no morphological change and most of the cells were viable. Interestingly, apoptotic cells were observed when the cells were preincubated with a serine/threonine phosphatase inhibitor, calyculin A, and then exposed to a toxin concentration of 0.1 microg/ml. This is the first report that lethal toxin of the anthrax bacillus can induce both necrosis and apoptosis and that protein phosphatases are implicated in the regulation of bacterial toxin-induced apoptosis.

[The phagetype and detection of drug-resistance of Salmonella typhi-muriun in Fujian province]

Salmonella typhimurium has accounted for 29.43% of total Salmonella according to the surveillance in Fujian province since 1975. Seven common phagetypes of S. typhimurium were found. The principal phagetype was 7774, which accounted for 46.6% of all phagetypes. S. typhimurium was significantly more resistant to antibiotics in early 1990's than in the 1980's. 57%-72% of the S. typhimurium strains were resistant to aminoglycosides (except amikacin), about 70% were strains resistant to first generation penicillins and tetracyclins while a high proportion of S. typhimurium strains have rapidly become resistant to new broad-spectrum penicillins. The strains of S. typhimurium which are resistant to the first and the second generation of cephalothins become sensitive only to the third generation of cephalo thins. There has been 20% of S. typhimurium strains resistant to some types of quinolones. All S. typhimurium were sensitive to norfloxacin, ofloxacin and ciprofloxacin. In the early 1980's resistant strains to 2-3 kinds of antibiotics accounted for 97%, and nostrains was resistant to more then 6 kinds of antibiotics. In the early 1990's, the strain resistant to 2-3 kinds of antibiotics were less than 20%; while strains resistant to more than 10 kinds of antibiotics were 66%. The increasing rate of resistant strains to antibiotics with widening of drug resistant pattern and the extensive appearance of multiresistant strains have become serious problems to be solved.

Determination of acetylcholine by on-line microdialysis coupled with pre- and post-microbore column enzyme reactors with electrochemical detection

A sensitive procedure consisting of a pre- and post-microbore column reactor sequence of a LC-electrochemical detection system coupled with on-line microdialysis system is described in the present study to measure endogenous acetylcholine concentration in freely moving rats. The pre-column packed, with immobilized choline oxidase and catalase, was used to remove choline, whereas the post-column, packed with immobilized acetylcholine oxidase and choline oxidase, was used to measure acetylcholine selectively. The detection limit of acetylcholine oxidase and choline oxidase, was used to measure acetylcholine selectively. The detection limit of acetylcholine was found to be 5 fmol/microliter (50 fmol/10 microliters). The usefulness of the described methodology was evaluated by examining the change in the striatal acetylcholine concentration of freely moving rats after physostigmine (0.5 mg/kg, s.c.) administration.

High maternal serum free beta-hCG levels in Down syndrome pregnancies: a preliminary report

To investigate the serum free beta-human chorionic gonadotropin (beta-hCG) value in women carrying Down syndrome fetus, we have retrospectively studied 11 Down syndrome pregnancies and 200 singleton unaffected pregnancies between 15 and 22 weeks' gestation. Each affected pregnancy was assigned at least 15 control cases matched with maternal age and gestational age. The median value of free beta-hCG in Down syndrome pregnancies and unaffected pregnancies was 2.56 multiples of the median (MoM) and 1.06 MoM, respectively. The mean free beta-hCG value after log transformation in Down syndrome pregnancies was 2.01 MoM that was significantly different from that of unaffected pregnancies (1.05 MoM, P = 0.024). There were 54.6% (6/11) of Down syndrome pregnancies and 5% (10/200) of unaffected pregnancies with free beta-hCG levels greater than 2.5 MoM. It is suggested that free beta-hCG may be a potentially useful and superior marker in the detection of Down syndrome pregnancies in our population.

[Sequence analyses of Epstein-Barr virus (EBV) Bam HI F DNA fragment in EBV associated diseases]

In order to compare nucleotide differences of Epstein-Barr virus (EBV) Bam HI F DNA fragment from various EBV associated diseases, polymerase chain reactions (PCR) were used to amplify a subfragment (nucleotides 55,381-56,020) of the F fragment from different tissue DNAs, including 20 NPCs, 2 B-cell lymphomas, 2 T-cell lymphomas, 3 infectious mononucleosis (IM), and 3 normal controls. DNA sequences were determined by PCR direct sequencing or sequencing after DNA cloning. The PCR products were cloned into pGEM-3Z vector, then the resulting recombinant plasmids were used to transform DH5 alpha competent cells. Plasmid DNAs from the correct transformants were prepared for DNA sequencing. The results showed that the proportion of the f variant in NPCs, B-cell lymphomas, T-cell lymphomas, IMs, and normals were 40%, 0%, 0%, 33%, and 33%, respectively. Because the f variant was not specifically more prevalent in NPC tissues compared to the non-tumor tissues, we speculate that there is no strong association between the f variant and NPC. These results were different from other reports. Coinfection of the F strain and the f variant was found both in some NPC patients and normal individuals. Analyses of Bam HI F subfragments of 35 EBV isolates from the 30 tissue DNAs revealed that there were changes at four corresponding positions of the B95-8 strain. They were nucleotide T at 55,473 replaced by G, an insertion of TGT after nucleotide 55,543, nucleotide A at 55,564 replaced by G, and nucleotide T at 55,958 replaced by C. These 4 nucleotide changes may confer a character of Taiwan strains. The nucleotides of the F strain at coordinates 55,519, 55,596, 55,680, 55,703, and 55,895 were T, T, A, A, and C, and those for the f variant were C, C, C, C, and T. These two patterns were not correlated with types A and B of EBV.