Effects of specimen load-bearing and free surface layers on the compressive mechanical properties of cellular materials

The influence of load-bearing surface layers on Young's modulus was determined for cancellous bone and polyurethane foam specimens of three different heights cut from each material: 16, 9, and 5 mm for bone specimens (cross-sectional area A = 81 mm2) ranging in density from 0.04 to 0.32 g cm-3; 20, 10, and 5 mm for foam specimens (A = 100 mm2) ranging in density from 0.064 to 0.64 g cm-3. The compressive elastic modulus of the 5 mm bone specimens was significantly smaller (42%) than that of the 16 mm bone specimens. A similar change in elastic modulus was also observed for the foam specimens, but the height effect diminished in a relatively linear manner as the foam density increased. For a height change from 20 to 5 mm, the foam modulus difference ranged from a 41% decrease for the lowest density specimens (p = 0.064 g cm-3) to an insignificant change (< 1.8%) for the highest foam density specimens (p = 0.64 g cm-3). The specimen height effect on elastic modulus was hypothesized to result from a higher deformation (compliance) of the cellular materials in the load-bearing or contacting surface layer than in the bulk. A mathematical formula was derived to predict the variation in measured elastic modulus (E) caused by the contacting surface layer modulus (Ecs) to bulk modulus (Eb) ratio (Y = Ecs/Eb) and contacting surface layer height (hcs) to sample height (h) ratio (t = hcs/h): E/Eb = Y/[Y(1-t)+t]. Predicted differences in the measured modulus associated with graduated specimen heights were verified experimentally by regional strain measurements of the foam and bone samples using an optical microscope. The influence of free-surface layers was also determined for the foam specimens with cross-sectional areas 1.21 and 10 times the load-bearing area of a load platen, but the measured differences were small (< 10%) compared to that of the load-bearing surface layer influence. In future compressive mechanical testing of cellular materials, specimens < 10 mm in height should be avoided, particularly specimens with low bulk density or high porosity.

[Effects of "moist burn ointment--mei bao" on production of IL-2 in burn rats and its clinical problems]

Since "Mei Bao" has been used in clinical treatment of burn wounds, there is a diversity of opinions concerning its effect. We carried out a series of experiments to observe its therapeutic effect, bacteriostatic property, and its effect on production of IL-2 in thermally injured rats. These results indicate that obvious infection occurred after its use on burn wounds and healing is delayed. Hyperplastic scars accompanying with deformity appeared after healing. The cost of treatment is high. There is no improvement in immune reaction, and no bacteriostatic property is observed.

The value of hepatitis B x antigen as a prognostic marker in the development of hepatocellular carcinoma

Chronic infection with hepatitis-B virus (HBV) is associated with high risk for the development of hepatocellular carcinoma (HCC). Several studies have implicated that the X gene product(s) of HBV are important to the pathogenesis of HCC. This study tests the hypothesis that immunohistochemical detection of hepatitis B x antigen (HBxAg) is closely associated with HCC. The patterns of HBxAg were determined by staining in tumor and non-tumor liver sections from 30 Chinese patients with HBV-associated HCC, and the results were compared with other markers of infection. HBxAg was the most prevalent marker of HBV infection both in tumor and in non-tumor tissues of HCC patients, as compared with the hepatitis-B surface and core antigens. This pattern was observed among carriers as well as several patients who were HBsAG- in serum. The HBxAg staining results were validated by Southern blotting with an X-region probe and by Western blotting with anti-HBx. These results suggest that the persistence of HBxAg is important to the pathogenesis of early HCC and that HBxAg expression in the liver during chronic HBV infection may be an important prognostic marker for the development of HCC.

Capillary electrophoresis of abnormal hemoglobins associated with alpha-thalassemias

Capillary electrophoresis was evaluated for separation of hemoglobin species associated with alpha-thalassemias, and for identification of hemoglobin variants commonly found in the same human populations. Separation of hemoglobins was achieved using capillary isoelectric focusing with chemical mobilization; visible-wavelength absorbance detection was used to identify hemoglobins against a background of nonheme-containing proteins. This technique could easily differentiate hemoglobins Bart's and H (associated with alpha-thalassemias) from hemoglobin variants. Analysis of globin chains derived from intact hemoglobins was performed by free zone capillary electrophoresis under denaturing conditions. This technique was useful for distinguishing Hb Bart's and Hb H, and for confirming the identity of hemoglobin variants.

Detection of the actin scavenger system in burn wound fluid

The intravascular actin scavenger system depolymerizes and sequesters actin released after tissue injury. Studies were carried out to determine if this system is active in the extracellular space during wound repair. Using burn wound fluid as a noninvasive means for analyzing the wound environment, we measured actin accumulation and actin complex formation with the plasma proteins responsible for scavenger function. Actin at concentrations as high as 0.25 mg/ml ( approximately 5 micromol/L) was found in burn wound fluid samples from 9 of 11 patients. Wound fluid also contained the two plasma proteins that bind actin-gelsolin (both plasma and cytoplasmic forms) and Gc protein. Because actin in wound fluid was complexed with gelsolin and Gc protein, we conclude that the components of the actin scavenger system are functional in wound tissue. In addition, proteolysis of gelsolin, but not actin or Gc protein, appeared to occur at the wound site. Gelsolin proteolysis was accompanied by the appearance of 49 kd gelsolin fragments, and wound fluid samples lacking intact gelsolin also contained high metalloproteinase levels.

Hepatitis B x antigen and p53 are associated in vitro and in liver tissues from patients with primary hepatocellular carcinoma

To test the hypothesis that hepatitis B x antigen (HBxAg) binds to the tumor-suppressor protein p53, immunoprecipitation was carried out with monoclonal anti-x or monoclonal anti-p53 using radiolabeled HBxAg and p53 made by in vitro translation. The results showed that anti-p53 specifically immunoprecipitates HBxAg only in the presence of p53 and that anti-x specifically immunoprecipitates p53 only in the presence of HBxAg. to determine whether HBxAg binds p53 in vivo, immunoprecipitation and Western blot analysis of liver samples from 10 hepatitis B virus (HBV)-infected patients with primary hepatocellular carcinoma (PHC) were carried out. A protein band at 53,000 daltons that specifically immunoprecipitated with a monoclonal anti-x was identified as p53 by Western blotting with a monoclonal anti-p53. Anti-p53 specifically immunoprecipitated bands of 28,000, 17,000 and 13,000 daltons, which were identified as HBxAg polypeptides by Western blotting with anti-HBx. These findings suggest that HBxAg binds to p53 and that this association is important to the development of PHC.

Beyond Section 504: satisfaction and empowerment of students with disabilities in higher education

College and university students with disabilities were surveyed to determine their levels of satisfaction with accessibility, special services, and accommodations at their schools. In addition, students were requested to identify barriers to postsecondary education, improvements in services, and other concerns. Respondents generally expressed satisfaction with the services that they had received. However, the majority indicated that they had encountered barriers to their education, including a lack of understanding and cooperation from administrators, faculty, staff, and other students; lack of adaptive aids and other resources; and inaccessibility of buildings and grounds. Recommendations were made for improving the delivery of services and self-advocacy of students with disabilities.

Effects of some opiates and opioid peptide eyedrops on ocular melatonin regulation in rabbits

Levels of melatonin in rabbit eye tissues were detected by radioimmunoassay. Solutions of met-enkephalin, leu-enkephalin, alpha-endorphin and beta-endorphin were given topically. Met-Enkephalin and alpha-endorphin lowered levels of melatonin in the iris, iris root-ciliary body, retina and choroid; leu-enkephalin raised levels in the retina and lowered them in other tissues. beta-Endorphin only lowered levels in the iris root-ciliary body. DAGO (a mu agonist) given i.v. lowered levels of melatonin in the iris, iris root-ciliary body and retina. The delta and sigma agonists given i.v. only lowered levels in the iris root-ciliary body, and a kappa agonist given i.v. raised levels in the ciliary body. No opiate binding sites could be detected in the rabbit iris or iris root-ciliary body for any class of receptor. Our data suggest opioids may be useful for treating glaucoma.

Differential metabolism of tetrahydrobiopterin in monoamine neurons: a hypothesis based upon clinical and basic research

This chapter has attempted to describe and integrate some of the clinical and basic research that support our hypothesis that the metabolism of BH4 is normally heterogeneous across different populations of monoamine-containing neurons. Based upon this hypothesis, there may now be reason to support the idea that certain neuropsychiatric illnesses, which are though to be the result (at least in part) of altered monoamine metabolism, might find their roots in an abnormal metabolism of BH4 within specific monoaminergic cell groups. Such a specific dysfunction might not be apparent in the rest of the brain or peripheral nervous system, thereby being difficult to detect. Perhaps the application of molecular biological techniques to studies of BH4 metabolism in man will shed new light on these problems.

Analysis of alkylpyrrole autoxidation products by high-performance liquid chromatography with thermospray mass spectrometry and UV photodiode-array detection

A method employing high-performance liquid chromatography with thermospray mass spectrometry (TSP-MS) and photodiode-array detection was developed and applied to the analysis of autoxidation products of 2,5-dimethyl-N-alkylpyrroles in aqueous solution under air or 18O2. Numerous oxidation products were separated, characterized and categorized, primarily as (1) non-polar oligomers without incorporated oxygen, and (2) polar, oxygen-containing monomers. Kinetic studies showed that oligomerization was the dominant autoxidation pathway, with production of unstable dimers and trimers and, ultimately, a high-molecular-mass sediment. TSP-MS together with UV and proton nuclear magnetic resonance spectral data revealed that both the dimer and trimer contained a novel methylene bridge. These results suggest that this method is suitable for the analysis of alkylpyrrole autoxidation products that may be relevant to hexane neuropathy and products that are responsible for the instability of fuels in storage.

Direct measurement of oxygen free radicals following cardiac failure of ischemic dog myocardium with the electron spin resonance technique

OBJECTIVE

To determine whether the involvement of oxygen-derived free radicals in the pathogenesis of ischemic cardiac failure in dogs.

DESIGN

Free radicals were measured in normal and ischemic myocardium from dogs with cardiac failure induced by acute coronary occlusion. The changes in free radical production in ischemic myocardium (compared with normal myocardium with or without polymorphonuclear leukocytes) were studies, with plasma superoxide dismutase and malondialdehyde analyzed concurrently.

MAIN RESULTS

The results showed that the oxygen free radicals in the ischemic myocardium were about 42.5% higher than those in the normal myocardium, about 67.8% higher than those in the normal myocardium washed with normal saline and about 60.5% higher than those in the ischemic myocardium washed with normal saline (P < 0.05). Compared with controls, the concentration of malondialdehyde in ischemic dog myocardium was increased markedly. The activity of plasma superoxide dismutase was not significantly different between control dogs and dogs with ischemic cardiac failure.

CONCLUSIONS

The current results indicate that there was increased production of free radicals and peroxidative damage in ischemic myocardium of dogs with cardiac failure. Polymorphonuclear leukocytes appear to be a main source of free radicals in dog with ischemic cardiac failure.

[Isolation of Neisseria from human dental plaque and study of characteristics of acid degradation]

The Neisseria was isolated and identified from human dental plaque.The incidence of Neisseria was 100%.The N.Sicca was the predominant group.The results of sugar metabolism of Neisseria indicated that they were not only able to produce acid while sugar was offered sufficiently,but also degrade lactate evenacetate to supply energy after sugar was consumed.

Low frequency of p53 mutations observed in a diverse collection of primary hepatocellular carcinomas

Recent studies of the p53 tumor suppressor locus (designated TP53) in primary hepatocellular carcinoma (PHC) have identified a high frequency of codon 249 mutations. Due to the geographic location from which the samples were obtained and the substitution observed, the mutation was suggested to be attributable to aflatoxin B1 (AFB1) exposure. To determine the generality of this phenomenon, we have examined PHC tissues from 107 geographically and ethnically diverse sources. The frequency of p53 gene mutations was evaluated by using PCR/restriction-digest methods, GC-clamp (G+C-rich sequence) denaturing gradient gel electrophoresis, and DNA sequencing. The mutation rate observed in tumors from high-AFB1-exposure regions (25%) was more than double the rate observed in low-exposure regions (12%) but lower than the 50% frequency previously reported. Codon 249 mutations occurred at a much lower frequency than previously reported (2 of 107 samples examined). These results suggest that changes in DNA encoding p53 may not represent primary oncogenic effects but instead represent genetic changes related to tumor progression. High AFB1 levels may facilitate the generation of these progressional changes, but not by inducing a specific p53 gene mutation at codon 249 as previously reported.

Quantitation of rodent catalepsy by a computer-imaging technique

Catalepsy is usually defined as a behavioral state in which an animal maintains an unnatural posture for an extended period of time. While numerous laboratory models have been developed for assessing catalepsy, a common problem encountered with most procedures is the difficulty in quantitating immobility. Measurement of catalepsy is still frequently subjective in nature. To eliminate this subjectivity, a computer-based technique was developed for quantitating catalepsy in mice and rats as measured on the elevated ring. The system consisted of a video camera that was focused on either three mice or two rats. Their behavior was recorded during a 5-min session on videotape that was subsequently transmitted to a Macintosh II microcomputer via a Scion Image-Capture 2 board. A modification of the NIH Image 1.17 public domain program allowed the image of the rat to be transformed to a purely black or white image by assigning pixel values of either 0 or 256. The subsequent captured image was preprocessed in an identical manner and each pixel was subtracted from its corresponding pixel in the previous frame. Thus, changes in animal posture between the two frames can be quantitated. One subtraction cycle (acquisition, bilevel processing, and subtraction) was repeated at an average rate of approximately one per second. To quantitate immobility by image analysis, each frame was subtracted from the previous frame during a 5-min session. The resulting data were sorted according to the magnitude of movement (number of changed pixels) and plotted vs. time.(ABSTRACT TRUNCATED AT 250 WORDS)

Capillary electrophoresis of hemoglobins and globin chains

Capillary isoelectric focusing (cIEF) and free zone capillary electrophoresis were evaluated for separation of native hemoglobins and globin chains. High-resolution separations of adult human hemoglobin A, fetal human hemoglobin F, and hemoglobin variants S and C were obtained using cIEF with cathodic mobilization. Absorbance detection in the UV and visible regions were compared, and on-line fast UV or visible-wavelength scanning detection was used to obtain spectral information on separated components. Globin chain analysis was performed on the same hemoglobin species by free zone capillary electrophoresis following precipitation of the protein with acidic acetone. Free zone separations were carried out at low pH in the presence of 7 M urea.

Electron spin resonance determination and superoxide dismutase activity in polymorphonuclear leukocytes in congestive heart failure

Electron spin resonance spin trapping technique was used to measure the generation of active oxygen free radicals during the respiratory burst of phorbol myristate acetate-stimulated leukocytes, and the superoxide dismutase activity in healthy subjects and in patients with congestive heart failure. The authors also measured the concentration of peroxidation products (primarily malondialdehyde) by the thiobarbituric acid method. Experimental results showed that the electron spin resonance spectra obtained during the respiratory burst of polymorphonuclear leukocytes stimulated with phorbol myristate acetate primarily were those of the spin adduct of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) with the superoxide anion and to a lesser extent those of DMPO with hydroxyl radical. Compared with healthy subjects, the release of oxygen free radicals in the respiratory burst of polymorphonuclear leukocytes stimulated with phorbol myristate acetate and the concentration of thiobarbituric acid reactive product in plasma were significantly increased in patients with congestive heart failure while the activity of superoxide dismutase was markedly lower. The increased production of oxygen free radicals by polymorphonuclear leukocytes and the decreased capability of antioxidative defences might play an important role in the generation and development of cardiac failure.

A three-dimensional variable geometry countercurrent model for whole limb heat transfer

A new formulation of the combined macro and microvascular model for heat transfer in a human arm developed in Song et al. [1] is proposed using a recently developed approximate theory for the heat exchange between countercurrent vessels embedded in a tissue cylinder with surface convection [2]. The latter theory is generalized herein to treat an arm with an arbitrary variation in cross-sectional area and continuous bleed off from the axial vessels to the muscle and cutaneous tissue. The local microvascular temperature field is described by a "hybrid" model which applies the Weinbaum-Jiji [3] and Pennes [4] equations in the peripheral and deeper tissue layers, respectively. To obtain reliable end conditions at the wrist and other model input parameters, a plethysmograph-calorimeter has been used to measure the blood flow distribution between the arm and hand circulations, and hand heat loss. The predictions of the model show good agreement with measurements for the axial surface temperature distribution in the arm and confirm the minimum in the axial temperature variation first observed by Pennes [4] for an arm in a warm environment.

Characterization of isothiocyanates, thioureas, and other lysine adduction products in carbon disulfide-treated peptides and protein

Carbon disulfide (CS2) is an industrial solvent used in rayon production and as an organic synthetic precursor. It is also a member of the class of neuropathy-inducing xenobiotics known as the "neurofilament (NF) neurotoxicants". Current hypotheses propose direct reaction of CS2 with NF lysine epsilon-amine moieties as a step in the mechanism of this neuropathy. In this study, covalent CS2 binding in a lysine-containing dipeptide and in bovine serum albumin (BSA) in vitro was characterized. Dipeptide and BSA, incubated with 14CS2, exhibited stable incorporation of radioactivity after removal of unbound CS2 and reincubation in physiological buffer for up to 10 days. In contrast, free thiol levels decreased from a maximum immediately following CS2 exposure to near-base-line levels after 10 days, consistent with time-dependent conversion of initially formed N-substituted dithiocarbamate adducts into secondary products. HPLC/thermospray-MS and HPLC/UV photodiode-array analysis of CS2-dipeptide adducts confirmed dithiocarbamate formation and demonstrated their conversion into N-alkylisothiocyanates and, ultimately, N,N'-disubstituted thioureas and ureas. The results of UV spectrophotometry of CS2-treated BSA were also consistent with loss of dithiocarbamate and appearance of thioureas. Similar time-dependent formation of these products, in addition to N,N'-disubstituted thiuram disulfides, was demonstrated in CS2-treated BSA by means of 13C-NMR spectroscopy. SDS-PAGE analysis of adducted protein revealed a discrete, higher mobility band, likely representing a specific intramolecular cross-link. In contrast, no evidence for intermolecular protein cross-linking was obtained. Identical results were obtained with cysteinyl-blocked BSA, indicating the lack of formation of N,S-dialkyldithiocarbamate (dithiourethane) cross-links in these preparations.(ABSTRACT TRUNCATED AT 250 WORDS)

A DNA hybridization assay for use in drug sensitivity tests in vitro for Plasmodium falciparum under field conditions

A deoxyribonucleic acid (DNA) hybridization technique was applied to in vitro drug sensitivity testing of P. falciparum using a synthetic 21-mer oligonucleotide coupled to alkaline phosphatase (PFR1-AP) to monitor development of parasite stages in culture. The density of the coloured spot clearly distinguished schizonts from ring forms. This assay system was applied in the field on Hainan Island, China. Blood samples obtained from patients were cultivated in the presence of antimalarial drugs and the minimum drug concentration required to inhibit development of parasites was determined by the DNA hybridization assay and by microscopical observation of Giemsa-stained blood smears. The 2 methods yielded identical results, indicating that the DNA hybridization assay can be used for in vitro drug sensitivity testing under field conditions.

Separation of albumin from autologous plasma by heat

A simplified technique has been developed to separate albumin from the plasma of a patient undergoing treatment with plasma exchange. This albumin can be returned to the patient to maintain colloid osmotic pressure without risk of transmitting disease. Patient plasma is obtained by apheresis. It is heated at 70 degrees C for 60 minutes to denature and remove autoantibodies, immune complexes, and abnormal globulins. The resulting low-concentration albumin solution (LCAS) retains its natural properties. Immunologic analysis by gel diffusion shows a reaction pattern of complete identity with that of human serum albumin. The albumin in LCAS is more than 90 percent of the remaining protein, as determined by scan of a cellulose acetate electrophoresis pattern. More than 97 percent of the albumin is in monomer form, as judged by polyacrylamide gel electrophoresis. No patient antibodies to neonantigens in the heat-treated albumin can be identified by double radial immunodiffusion. More than 80 percent of the plasma albumin is recovered in LCAS. LCAS is safe and efficient for use in plasma exchange.

Hepatitis B x antigen and polymerase antibodies in the serum of hepatitis B carriers with or without hepatitis delta virus infection. Effects of interferon treatment

Previous work has shown that the hepatitis B x antigen (HBxAg) and antibodies directed against the polymerase of hepatitis B virus (anti-pol) are early markers of hepatitis B virus (HBV) replication in natural infections. The present study was carried out to test the hypothesis that the appearance of one or both of these markers signaled reactivation in chronic carriers with liver disease who were treated with alpha-interferon (IFN). The results show that HBV DNA decreased among the patients who responded to therapy, and that among these responders, neither HBxAg nor anti-pol became detectable in serum for 12 months after treatment, in contrast to controls. Hence, the loss of HBxAg and anti-pol correlate with decreased levels of HBV DNA in response to IFN therapy. However, different patterns of HBxAg and anti-pol were observed among alpha-IFN-treated HBV carrier patients who were also chronically infected with the hepatitis delta virus (HDV). The treatment of such patients often resulted in the loss of HDV RNA from serum and delta antigen from liver. Most of these patients had increased levels of HBV DNA in serum. HBxAg and/or anti-pol also became detectable in patients who lost markers of HDV, implying that the suppression of HDV by IFN is accompanied by the appearance of early markers of HBV reactivation in some of the treated patients.

Effects of some natural products on sugar cataract studied with nuclear magnetic resonance spectroscopy

Four commercial anticataract drugs and five flavonoids isolated from Chinese herbs were studied on their effects to inhibit sugar cataract formation in vitro using 13C-nuclear magnetic resonance spectroscopy (MRS). Pa-Wei-Di-Huan-Wan (PWDHW) and Zhang-Yan-Ming (ZYM) were effective in inhibiting sorbitol formation, whereas Bai-Nei-Ting (BNT) and Pearl Min-Mu-Ye (Pearl MMY) were ineffective in inhibiting sorbitol formation. Among five flavonoids tested, four were moderately effective in inhibiting sorbitol formation, and one was totally ineffective up to 1 x 10(-4)M used.

[Influence of dietary selenium level on immune function of rats with esophageal tumors induced by methylbenzylnitrosamine (NMBzA)]

The influence of dietary selenium of the incidence of esophageal tumor induced by NMBzA and the immune function during carcinogenesis were studied in rats fed with Torula yeast diet and survived for 18 weeks. The incidences of esophageal tumors were statistically not significant among rats on normal, high and low selenium intake (P greater than 0.05). The level of plaque forming cells (PFC), delayed type hypersensitivity (DTH), natural killer cell activity (NK) were significantly higher in the high selenium diet group than those of the low selenium diet group (P less than 0.05). The authors believe that the modulation of dietary selenium can alter the immune function of animals during carcinogenesis but the anticarcinogenic effect of selenium still needs further study.

Mechanism of action of sparfloxacin against and mechanism of resistance in gram-negative and gram-positive bacteria

The inhibition of DNA synthesis by sparfloxacin; accumulation of sparfloxacin into members of the family Enterobacteriaceae, Pseudomonas aeruginosa, and staphylococci; induction of recA in Escherichia coli; and the optimum bactericidal concentration (OBC) were measured, and killing kinetics at the OBC were estimated. The OBC and maximum recA-inducing concentration in E. coli were both 1 microgram of sparfloxacin per ml. Accumulation was rapid; two- to threefold more sparfloxacin than ciprofloxacin accumulated in staphylococci and more sparfloxacin accumulated in staphylococci than in gram-negative bacteria. Laboratory mutants with decreased susceptibilities to quinolones alone or multiply resistant were selected from the Enterobacteriaceae and Staphylococcus aureus by using sparfloxacin.

[A study on the methods for correcting the error in measurement of children blood pressure]

The blood pressures of a group of children was obtained with sphygmomanometer cuffs of varying widths. It was suggested that the cuff width can be effect for accuracy of blood pressure determination, then a correct formula of blood pressure determination using an inadequate cuffs was calculated. The efficacy and feasibility of the formula was tested in another two groups of children. The production of the formula made a possibility for practicing the proposal of American Heart Association in which the width of an adequate cuff was believed to be 40% of the circumference in middle arms. The formula was simple and convenient and should be used in childhood prophylactic medicine, healthy care especially in popularized measurement of children blood pressure and scientific cooperative investigation.

High performance isoelectric focusing using capillary electrophoresis instrumentation

High performance isoelectric focusing in capillaries provides rapid, high resolution separation of proteins based on their isoelectric points. Results can be obtained in a matter of minutes with little or no sample preparation. The technique requires the use of coated capillaries to reduce electroendosmosis so that stable, focused zones can be attained. Once focused, protein zones may be mobilized by the addition of salt to the catholyte or anolyte buffer. On-tube UV monitoring enables direct detection of sample components during mobilization with mass sensitivity equal to that of silver staining. The linear relationship between mobilization time and isoelectric point allows the technique to be used for estimation of protein pI. Demonstrated applications include separation of proteins in biological fluids with possible clinical applications, and characterization of biopharmaceutical proteins and monoclonal antibodies.

[SEM study of invasive characteristics of colorectal cancer]

This paper reports the results of a study on the invasive characteristics of 22 colorectal cancer by scanning electron microscopy (SEM). The results showed that adenocarcinoma cells stretching polymorphic pseudopodia penetrated into peripheral tissue and adhered to or invaded the vessels, but most of the mucoid carcinoma cells migrated separately into the tissue clefts and invaded the vessels. The invasive mode had dominant differentiation in two typical cancer. The author believes that colorectal cancer possesses two invasive factors: ameboid movement and destroying tissues by lysozyme.

[Extraction-spectrophotometric determination of copper in tablets and injections of Chinese medicine]

Cu reacts with neo-cuproin and eosin Y to form a coloured associated complex. In chloroform its apparent E value is 6.83 X 10(4) 1 mol-1 cm-1 at lambda = 544 nm. We used this system to determine the contents of trace copper in some tablets and injections of Chinese medicine. This method is simple, highly sensitive and selective.

On the generalization of the Weinbaum-Jiji bioheat equation to microvessels of unequal size; the relation between the near field and local average tissue temperatures

The extensive series of experiments reported in Lemons et al. [1] show that measureable local tissue temperature fluctuations are observed primarily in the vicinity of the 100-500 micron countercurrent vessels of the microcirculation and thus strongly support the basic hypothesis in the new bioheat equation of Weinbaum and Jiji [2] that these countercurrent microvessels are the principal determinants of local blood-tissue heat transfer. However, the detailed temperature profiles in the vicinity of these vessels indicate that large asymmetries in the local temperature field can result from the significant differences in size between the countercurrent artery and vein. Using the superposition techniques of Baish et al. [9], the paper first presents a solution to the classic problem of an unequal countercurrent heat exchanger with heat loss to the far field. This solution is then used to generalize the Weinbaum-Jiji bioheat equation and the conductivity tensor that appears in this equation to vessels of unequal size. An asymptotic analysis has also been developed to elucidate the relationship between the near field temperature of the artery-vein pair and the local average tissue temperature. This analysis is used to rigorously prove the closure approximation relating the local arterial-venous temperature difference and the mean tissue temperature gradient which had been derived in [2] using a more heuristic approach.

Microskin grafting. I. Animal experiments

This article reports a new grafting technique--microskin grafting. These experiments were carried out in rabbits, and used a small amount of autograft minced into tiny pieces and then spread on a piece of homograft. The combined autograft plus homograft was then transplanted onto the wound of a rabbit. In 12 rabbits, the microskin grafts took well and covered the wound completely in 8 rabbits. The expansion ratios of the micrografts were from 7:1 to 15:1. The healing time of the wound was from 19 to 35 days. The operation failed in 4 rabbits because of the homograft moving. Histological sections revealed that microskin grafts orientated upwards can grow well and those orientated in a lateral or downward direction can grow too. This technique is an effective procedure for repairing extensive wounds with smaller donor sites.