Analysis of the pediocin AcH gene cluster from plasmid pSMB74 and its expression in a pediocin-negative Pediococcus acidilactici strain

The 3,500-bp pap operon in the 8,877-bp plasmid pSMB74 contains a cluster of four genes, papABCD, of which papA encodes prepediocin (A. M. Motlagh, M. Bukhtiyarova, and B. Ray, Lett. Appl. Microbiol. 18:305-312, 1994). The cluster without the promoter was cloned in the shuttle vector pHPS9. An Escherichia coli strain and a pediocin-sensitive Pediococcus acidilactici strain transformed with the recombinant plasmid, pMBR1.0, produced pediocin AcH. Deletion analysis by introducing mutations in the four genes in pMBR1.0 revealed that only papA and papD were required for pediocin AcH production and that the gene product of papD has both translocation and processing functions. In the transformed minicells of E. coli chi 925 the proteins of the pap cluster were synthesized, indicating no polar effect due to deletion.

Intestinal venous drainage through the liver is a prerequisite for oral tolerance induction

One feature of enteric mucosal immunity is oral tolerance (OT), a state of diminished systemic immune responsiveness to an antigen induced by previous oral feeding of that antigen. Because OT induction requires an interaction between the intestinal and systemic immune systems, the authors plan to use it as a method in experimental small bowel transplantation (SBT) to evaluate the ability of the intestinal allograft to cooperate immunologically with the host. Two different methods have been used in experimental SBT to establish graft venous drainage: anastomosis of the graft mesenteric vein to the recipient portal vein or to the inferior vena cava. This experiment was designed to examine the role of the intestinal venous drainage routes in OT induction. Rats with a surgically created mesenterico-caval shunt (MCS) and their sham controls received an immunization protocol to induce OT to ovalbumin. The results showed that OT was readily induced in the sham animals, but not in the animals with MCS. These results indicate that intestinal venous drainage through the liver plays a central role in OT induction. Therefore, future analyses of OT in allogeneic SBT will require an animal model with portal venous drainage of the intestinal graft.

Lack of graft-versus-host disease after fetal intestine transplantation

Clinical small bowel transplantation has often been complicated by lethal graft-versus-host disease (GVHD), attributed to the numerous allogeneic immunocompetent lymphocytes contained in the graft. Because the fetal immune system is relatively immature, the authors hypothesized that the risk of GVHD after small bowel transplantation might be diminished by using the fetal intestine as the donor organ. This experiment tested this hypotheses in a rat model. Jejunoileal segments harvested from Lewis (LEW) rat fetuses were transplanted subcutaneously into adult recipients of either syngeneic LEW or semiallogeneic LEW x Brown-Norway F1 (LBNF1) strains. The recipients had follow-up for 21 days after transplantation to assess the growth of the intestinal grafts ("neogut") and evaluate for GVHD. Growth of the intestinal grafts was observed in 65% (53 of 82) of the recipients, with a neogut weight of 4.5 +/- 3.7 g and length of 2.8 +/- 2.1 cm. No significant difference in graft survival rate or neogut weight and length was found between the LEW and LBNF1 recipients. Histopathologic examination of the neogut showed a mature intestinal architecture similar to that of normal adult rat intestine, with well-developed enteric lymphoid tissues including Peyer's patches. However, no clinical or histopathologic evidence of GVHD was found in any of the LBNF1 recipients. These results are consistent with the author's hypothesis and suggest that the use of fetal donor intestine for small bowel transplantation might have some immunologic advantages over the adult (immunologically mature) donor intestine.

Genetic diversity and multilocus associations in Cunninghamia lanceolata (Lamb.) Hook from The People's Republic of China

Open-pollinated seeds were assayed for allozyme polymorphisms at 24 loci to assess genetic diversity and multilocous associations in 16 populations of Cunninghamia lanceolata (Lamb.) Hook in the People's Republic of China. On average, the percentage of polymorphic loci was 88.0, the number of alleles per locus was 3.0, and the expected heterozygosity was 0.394. The distribution of genetic diversity was not correlated with the geographic and climatic variables of the populations. However, allele frequencies correlated linearly with the mean annual temperature of the populations at Mdh-1, Mdh-2, Mnr-2, Pgi-1, and Skdh-1 and with the altitude of the populations at Aph-4 and 6Pg-2. Of the total gene diversity 6% was attributed to among-population differentiation; 94% resided within populations. Two-locus gametic disequilibria were found in 15 of the 16 populations, and higher-order gametic disquilibria were significant in most populations. The gametic disequilibria did not correlate with geographic and climatic variables. The results suggest that population subdivision, founder effect, occurrence across diverse environments, a mating system dominated by inbreeding, and historical events from 2000 years of cultivation are contributing factors in the generation and maintenance of the multilocus genetic structure in this conifer.

Effect of electroacupuncture on the level of preproenkephalin mRNA in rat during penicillin-induced epilepsy

Our previous studies have shown that seizure induced by injecting penicillin (0.24 mg/2 microliters) into hippocampus could be inhibited by electroacupuncture (EA) probably via decreasing enkephalin content in hippocampus. To determine whether this change reflected the peptide synthesis, preproenkephalin (PPE) mRNA was detected in hippocampus and some other limbic structures during seizure and after EA treatment by in situ hybridization. Four hours after injecting penicillin into hippocampus, PPE mRNA levels were significantly increased by 10 folds in entorhinal cortex, subiculum, CA1 area of hippocampus, amygdaloid nucleus and piriform cortex, whereas EA treatment apparently attenuated the seizure-induced increase of PPE mRNA in the areas mentioned above. The results indicated that EA may regulate the biosynthesis of PPE in hippocampus during seizure by an alteration in gene transcription.

[Effects of beta-endorphin on blood pressure and heart rate in rats]

The present work was undertake to investigate the mechanism of changes of blood pressure and heart rate induced by beta-endorphin (beta-End) after microinjection into the Nucleus Amygdaloideus Centralis (AC) of anaesthetized rats. The results were as follows: (1) beta-End (100, 250 pg/microliters) injected into AC decreased both blood pressure and heart rate. (2) Both these effects could be antagonized by naloxone and beta-End anti-serum. (3) The effects of beta-End could also be reversed by phentolamine and propranolol. The results showed that the cardiovascular effects on beta-End were mediated by opioid receptors and through the intervention of adrenergic neurons.

Experimental high-frequency ultrasound can detect graft rejection after small bowel transplantation

Early diagnosis of graft rejection after small bowel transplantation (SBT) can allow prompt institution of vigorous immunosuppressive therapy, with resultant reversal of the rejection process. The current method for graft monitoring is random mucosal biopsy from a stomal site or through an endoscope. However, because early rejection often has a patchy distribution, it could be missed by random biopsy. We hypothesized that the pathological process of rejection would alter acoustic impedance of the tissue and thus change the ultrasonic patterns of the graft intestinal wall. If this hypothesis is correct, then high-frequency endoscopic ultrasound (US) could be used to monitor the entire transplanted bowel and guide the biopsy, with improved yields. This hypothesis was tested in a rat orthotopic SBT model. Sixty-two intestinal specimens (9 isografts, 12 allografts treated with cyclosporine A [CsA], 22 untreated allografts, and 19 intestines from normal rats) were collected for in vitro transluminal US imaging (30 MHz) and histopathologic study. The echo pattern of normal rat intestinal wall consisted of five echo layers that correlated spatially with the histological layers: the innermost hyperechoic layer 1, plus hypoechoic layer 2, corresponded to the mucosa; hyperechoic layer 3, the submucosa; anechoic layer 4, the muscularis propria; and hyperechoic layer 5, the serosa. The isografts and CsA-treated allografts were identical histologically and ultrasonically to normal intestine. However, the echo patterns of the untreated allografts had progressive loss of architectural stratification, with worsening rejection. The change began with patchy indistinctness and disruption of hyperechoic layers 1, 3 and 5, and progressed to total obliteration of the layers, with the intestinal wall becoming a nonstratified hypoechoic structure.(ABSTRACT TRUNCATED AT 250 WORDS)

[Pingyangmycin-induced chromosome damage in lymphocytes of laryngeal cancer patients]

Lymphocytes from 28 untreated laryngeal cancer patients and 23 healthy controls were cultured in vitro and exposured to pingyangmycin (bleomycin A5), a clastogen. The lymphocytes were arrested in metaphase and analyzed. The total chromosome aberration rate, mean chromatid break rate per cell and cell aberration rate were 1.98% +/- 0.05%, 0.57% +/- 0.35%, and 42.8% +/- 12% respectively for laryngeal cancer patients. However, for healthy controls these values were 0.94% +/- 0.04%, 0.28% +/- 0.12%, and 27% +/- 12% respectively. Statistical analysis showed there are significant differences between the two groups. The data indicate that under our experimental conditions chromatid break rate 0.40 can be considered to be a borderline value, 0.80 hypersensitive value. For any individual, if the chromatid break rate is 0.40 or more, one should be ranked as having cancer risk. If 0.80 or more, then, highly cancer risk.

Hydroxyl radicals generated in vivo kill neurons in the rat spinal cord: electrophysiological, histological, and neurochemical results

We have used microdialysis to establish an experimental model to characterize mechanisms whereby released substances cause secondary damage in spinal cord injury. We use this model here to characterize damaging effects of the hydroxyl radical (OH.) in vivo in the spinal cord. OH. was generated in vivo by pumping H2O2 and FeCl2/EDTA through parallel microdialysis fibers inserted into the spinal cord. These agents mixed in the tissue to produce OH. by Fenton's reaction. Two types of control experiments were also conducted, one administering only 5 mM H2O2 and the other only 0.5 mM FeCl2/0.82 mM EDTA. During administration of these chemicals, electrical conduction was recorded as one test for deterioration. OH. blocked conduction completely in 2.5-5 h and Fe2+/EDTA partly blocked conduction, but H2O2 alone did not cause detectable blockage. Histological examination supported the hypothesis that neurons were killed by OH., as Fe2+/EDTA and H2O2 alone did not destroy significant numbers of neurons. OH., H2O2, and Fe2+ all caused gradual increases in extracellular amino acid levels. These results are consistent with Fe(2+)-catalyzed free radical generation playing a role in tissue damage upon spinal cord injury.

Randomized, prospective trial of direct current versus bipolar electrocoagulation for bleeding internal hemorrhoids

Fifty patients with bleeding internal hemorrhoids unresponsive to 6 weeks of standard medical therapy were randomly assigned to receive treatment with direct current or bipolar electrocoagulation. Treatment groups were similar in bleeding severity and internal hemorrhoid grade. Treatment sessions were significantly longer for direct current electrocoagulation (8.8 +/- 0.2 minutes) than for bipolar electrocoagulation (0.1 +/- 0.03 minutes) (p < 0.001). When compared to the bipolar electrocoagulation group, direct current electrocoagulation patients had more procedural pain that terminated therapy (5 of 25 patients [20%] versus 0 of 25 [0%], for a difference of 20% [95% confidence interval, 4% to 36%]; p = 0.05) and prolonged pain after the procedure (4 of 25 patients [16%] versus 1 of 25 [4%], for a difference of 12% [95% confidence interval, -4% to 28%]; p = 0.35). However, more post-treatment rectal ulcerations were seen in the bipolar electrocoagulation-treated group (6 of 25 patients [24%] versus 1 of 25 [4%], for a difference of 20% [95% confidence interval, 2% to 38%]; p = 0.10). Treatment groups did not differ in number of treatment sessions or months of follow-up. The rates of success, defined as obliteration of the hemorrhoids or cessation of bleeding with reduction of the hemorrhoids to grade 1 or less, for the direct current electrocoagulation and the bipolar electrocoagulation groups were 88% and 92%, respectively. Failures in the direct current electrocoagulation group were uncontrollable bleeding (n = 1) and refusal to continue therapy because of pain (n = 2).(ABSTRACT TRUNCATED AT 250 WORDS)

(2,3)-alpha-Methylenepenams: synthesis and in vitro activity

A series of alpha-methylene penicillins was synthesized and SAR were studied. The alpha-isomers were found to be chemically reactive and biologically active in contrast to the beta-isomers. In addition, the alpha-isomers have broader spectrum of in vitro activity than the corresponding penicillins. Generally, the alpha-isomers are more active against gram-negative bacteria than the corresponding penicillins, but slightly weaker in potency towards gram-positive organisms.

Sonographic and computed tomography characteristics of liver ablation lesions induced by high-intensity focussed ultrasound

RATIONALE AND OBJECTIVES

The authors have previously demonstrated the ability of high-intensity focused ultrasound (HIFU) to extracorporeally induce selective tissue destruction in the liver without causing damage to the intervening abdominal wall. The potential usefulness of HIFU as a noninvasive therapy for liver cancer has been suggested. This study observes sonographic and computed tomography (CT) characteristics of HIFU-ablated liver tissue in an attempt to assess the possibility of using these imaging methods to monitor the therapeutic results.

METHODS

A sonoablated lesion was induced in the liver in each of 20 rabbits with a HIFU therapeutic system. Sequential imaging of the hepatic sonolesions with sonography and CT was performed up to 8 days after treatment, and the imaging patterns were correlated with the histopathology.

RESULTS

Hepatic sonoablated tissue could be clearly visualized by sonography as a hypoechoic lesion. On contrast-enhanced CT, the sonolesions were depicted as nonenhanced low-density regions. There was good correlation among the sizes of sonography- and CT-depicted lesions and pathologic specimens.

CONCLUSION

In this model, sonography and contrast-enhanced CT were useful imaging modalities for monitoring sonolesion evolution after HIFU treatment.

NTP technical report on the toxicity studies of a Chemical Mixture of 25 Groundwater Contaminants Administered in Drinking Water to F344/N Rats and B6C3F(1) Mice

Toxicity studies were performed with a chemically defined mixture of 25 groundwater contaminants, using dose levels considered to have environmental relevance. The mixture contained 19 organic compounds and six metals (shown below); the selection of these compounds was based primarily on the frequency of their occurrence in United States Environmental Protection Agency surveys of groundwater contamination in the vicinity of hazardous waste disposal sites. This report focuses primarily on 26-week drinking water toxicity studies with male and female F344/N rats and B6C3F(1) mice. The endpoints evaluated included histopathology, clinical pathology, neurobehavioral studies, and reproductive toxicity. Additional studies using this same chemical mixture are briefly reviewed in this report and include an evaluation of spermatogenesis in B6C3F(1) mice exposed to the chemical mixture for 13 weeks, a continuous breeding study with Sprague-Dawley rats and CD-1(R) Swiss mice, studies of myelotoxicity in B6C3F(1) mice exposed to the chemical mixture for up to 31.5 weeks, studies of immunosuppression in B6C3F(1) mice exposed for up to 13 weeks, in vitro mutagenicity assays in Salmonella typhimurium and Escherichia coli, and measures of genetic damage in bone marrow and peripheral blood of F344/N rats and B6C3F(1) mice in 2-week drinking water studies. In a 26-week drinking water study in which rats were administered the chemical mixture at composite contaminant concentrations of 0, 11, 38, 113, or 378 ppm, no deaths occurred and the body weight gain of high-dose males was slightly less than that of the controls. Water consumption decreased with dose and was 24% to 28% less than that of the controls at the highest concentration. Changes in organ weights occurred primarily in high-dose rats and included increased absolute and relative liver and kidney weights in females, increased relative kidney weight in males, and decreased absolute and relative thymus weights in males and females. Hematologic assessments indicated that rats receiving 378 ppm developed a microcytic anemia consistent with that accompanying iron depletion. Multiple foci of inflammation occurred in the liver of exposed rats. In high-dose females, these liver lesions were especially prominent and included bile duct and oval cell hyperplasia. Inflammation also occurred in the mesenteric lymph nodes, the adrenal gland, and the spleen. The amount of hemosiderin in the spleens of rats receiving the higher concentrations of the chemical mixture was less than normal. Components of a chemical mixture of 25 groundwater contaminants include acetone, aroclor 1260, arsenic, benzene, cadmium, carbon tetrachloride, chlorobenzene, chloroform, chromium, 1,1-dichloroethane, 1,2-dichloroethane, 1,1-dichloroethylene, 1,2-trans-dichloroethylene, di(2-ethylhexyl) phthalate, ethylbenzene, lead, mercury, methylene chloride, nickel, phenol, tetrachloroethylene, toluene, 1,1,1-trichloroethane, trichloroethylene, xylenes. In a 26-week study in which mice were exposed to the chemical mixture at concentrations of 0, 11, 38, 113, and 378 ppm in drinking water, there were no clear adverse effects noted in survival, weight gain, clinical pathology parameters, or histopathologic evaluations. Water consumption decreased with increasing dose, and water consumption by high-dose mice was approximately 40% less than that by the controls. In neurobehavioral assessments, no clear treatment-related effects were observed in measures of forelimb and hindlimb grip strength, hindlimb footsplay, motor activity, response to a thermal stimulus, or startle response in rats or mice evaluated at 6-week intervals throughout the 26- week drinking water studies. There were no effects on sperm morphology or motility or on estrous cycle length in rats or mice receiving the chemical mixture during the 26-week studies. Sperm concentration was decreased in F(1) CD-1(R) Swiss mice during continuous breeding studies, although there were no clear adverse effects on the fertility of Sprague-Dawley rats or CD-1(R) Swiss mice in th CD-1&reg; Swiss mice in these studies. Pup weight, the number of live males, and the number of male pups per litter were slightly decreased in dosed rats in the continuous breeding study in rats; the number of live female mouse pups in litters born of the F(0) and F(1) generations was decreased in the 378 ppm group. The significance of these observations, if any, is not known. F(1) mice receiving 378 ppm had increased incidences of hepatic inflammation compared to the controls. In female B6C3F(1) mice that received the chemical mixture in drinking water at concentrations as high as 756 ppm for 2 weeks or 378 ppm for 13 weeks, assessments of immune function showed suppression of hematopoietic stem cells and antigen-induced antibody-forming cells. This was manifested by impaired resistance to challenge with a nonlethal strain of mouse malaria, Plasmodium yoelii. Additional evidence of an adverse effect on hematopoietic stem cells was demonstrated by decreases in the in vitro colony-forming ability of granulocyte-macrophage progenitor cells and erythroid precursor cells isolated from female mice that had received the chemical mixture at a concentration of 378 or 756 ppm in 31.5 week studies. Potential genotoxic effects of the chemical mixture to the bone marrow of F344/N rats and B6C3F(1) mice were assessed in 2-week drinking water studies with concentrations as high as 756 ppm. Small increases in sister chromatid exchanges and micronucleated polychromatic erythrocytes occurred in the bone marrow of dosed male mice, and micronucleated polychromatic erythrocytes were also increased in dosed female mice. The chemical mixture did not induce mutations in Salmonella typhimurium strains TA98 and TA100 and did not induce DNA damage in Escherichia coli with or without metabolic activation. In summary, rats receiving drinking water containing a mixture of 25 common groundwater contaminants at levels of potential environmental relevance developed inflammatory lesions in the liver, spleen, lymph nodes, and adrenal gland, as well as evidence of an iron deficiency anemia. The inflammatory lesions could not be predicted based on the known toxic effects of the individual components of the chemical mixture. Mice exposed to similar concentrations of the chemical mixture did not show adverse effects in a standard toxicity study but developed deficits in bone marrow function, evidence of genetic damage, hepatic inflammation, and immunosuppression in other studies that generally included exposures to higher concentrations or exposures of longer duration. A no-observed-adverse-effect level for histologic injury (granulomatous inflammation of the liver) was 11 ppm in rats; however, no clear evidence for histologic injury was seen in mice exposed to concentrations of the chemical mixture as high as 378 ppm in a standard 26-week study. NOTE: These studies were supported in part by funds from the Comprehensive Environmental Response, Compensation, and Liability Act trust fund (Superfund) by an interagency agreement with the Agency for Toxic Substances and Disease Registry, U.S. Public Health Service.

NTP technical report on the toxicity studies of Pesticide/Fertilizer Mixtures Administered in Drinking Water to F344/N Rats and B6C3F1 Mice

Toxicity studies were performed with pesticide and fertilizer mixtures representative of groundwater contamination found in California and Iowa. The California mixture was composed of aldicarb, atrazine, 1,2-dibromo-3-chloropropane, 1,2- dichloropropane, ethylene dibromide, simazine, and ammonium nitrate. The Iowa mixture contained alachlor, atrazine, cyanazine, metolachlor, metribuzin, and ammonium nitrate. The mixtures were administered in drinking water (with 512 ppm propylene glycol) to F344/N rats and B6C3F1 mice of each sex at concentrations ranging from 0.1x to 100x, where 1x represented the median concentrations of the individual chemicals found in studies of groundwater contamination from normal agricultural activities. This report focuses primarily on 26-week toxicity studies describing histopathology, clinical pathology, neurobehavior/neuropathology, and reproductive system effects. The genetic toxicity of the mixtures was assessed by determining the frequency of micronuclei in peripheral blood of mice and evaluating micronuclei and sister chromatid exchanges in splenocytes from female mice and male rats. Additional studies with these mixtures that are briefly reviewed in this report include teratology studies with Sprague-Dawley rats and continuous breeding studies with CD-1 Swiss mice. In 26-week drinking water studies of the California and the Iowa mixtures, all rats (10 per sex and group) survived to the end of the studies, and there were no significant effects on body weight gains. Water consumption was not affected by the pesticide/fertilizer contaminants, and there were no clinical signs of toxicity or neurobehavioral effects as measured by a functional observational battery, motor activity evaluations, thermal sensitivity evaluations, and startle response. There were no clear adverse effects noted in clinical pathology (including serum cholinesterase activity), organ weight, reproductive system, or histopathologic evaluations, although absolute and relative liver weights were marginally increased with increasing exposure concentration in both male and female rats consuming the Iowa mixture. In 26-week drinking water studies in mice, one male receiving the California mixture at 100x died during the study, and one control female and one female in the 100x group in the Iowa mixture study also died early. It could not be determined if the death of either of the mice in the 100x groups was related to consumption of the pesticide/fertilizer mixtures. Water consumption and body weight gains were not affected in these studies, and no signs of toxicity were noted in clinical observations or in neurobehavioral assessments. No clear adverse effects were noted in clinical pathology, reproductive system, organ weight, or histopathologic evaluations of exposed mice. The pesticide/fertilizer mixtures, when tested over a concentration range similar to that used in the 26-week studies, were found to have no effects in teratology studies or in a continuous breeding assay examining reproductive and developmental toxicity. The California and Iowa pesticide mixtures were tested for induction of micronuclei in peripheral blood erythrocytes of female mice. Results of tests with the California mixture were negative. Significant increases in micronucleated normochromatic erythrocytes were seen at the two-highest concentrations (10x and 100x) of the Iowa mixture, but the increases were within the normal range of micronuclei in historical control animals. Splenocytes of male rats and female mice exposed to these mixtures were examined for micronucleus and sister chromatid exchange frequencies. Sister chromatid exchange frequencies were marginally increased in rats and mice receiving the California mixture, but neither species exhibited increased frequencies of micronucleated splenocytes. None of these changes were considered to have biological importance. In summary, studies of potential toxicity associated with the consumption of mixtures of pesticides and a fertilizer representative of groundwater contamination in agriculturative of groundwater contamination in agricultural areas of Iowa and California failed to demonstrate any significant adverse effects in rats or mice receiving the mixtures in drinking water at concentrations as high as 100 times the median concentrations of the individual chemicals determined by groundwater surveys. NOTE: These studies were supported in part by funds from the Comprehensive Environmental Response, Compensation, and Liability Act trust fund (Superfund) by an interagency agreement with the Agency for Toxic Substances and Disease Registry, U.S. Public Health Service.

Changes of hepatoma echo patterns with tumor growth. A study of the microanatomic basis in a rat model

OBJECTIVES

The echo patterns of human hepatoma vary considerably as the tumors grow. This sonographic study investigates the microanatomic basis of the echo-pattern changes in an animal model.

METHODS

ACI rats (n = 35) with intrahepatically implanted Morris hepatoma 3924A were imaged with 10-MHz ultrasound from days 7 to 28 after tumor implantation. The sonograms were precisely correlated with the histologic sections and microangiograms obtained from the same section plane.

RESULTS

Small hepatomas (size = 6.6 +/- 1.6 mm) without necrosis demonstrated a low-echo pattern. Medium-sized tumors (size = 11.7 +/- 3.3 mm) had a low-echo periphery and a high-echo center. The low-echo periphery corresponded to viable tumor and the high-echo core corresponded to central coagulation necrosis. Large tumors (size = 20.9 +/- 7.5 mm) with extensive necrosis revealed an irregular mixed-echo pattern.

CONCLUSIONS

The trend of increasing echogenicity of the hepatomas with tumor growth is due to the progression of coagulation necrosis.

Liver cancer ablation with extracorporeal high-intensity focused ultrasound

Recent animal studies have demonstrated the capacity of high-intensity focused ultrasound (HIFU) to extracorporeally ablate selective tissue targets in the liver without requiring surgical exposure of the liver or insertion of instruments into the liver. The potential value of HIFU as a noninvasive local treatment for human hepatic cancers has attracted considerable interest. This report reviews the current status of HIFU research and sets forth questions for future study.

Ganglion atrial natriuretic peptide in NaCl sensitive spontaneously hypertensive rats

Reports from other laboratories have shown that atrial natriuretic peptide (ANP) stores in sympathetic ganglia are increased during dietary NaCl supplementation in normotensive rats. We have previously demonstrated that dietary NaCl supplementation in NaCl sensitive spontaneously hypertensive rats (SHR-S) exacerbates hypertension and enhances peripheral sympathetic nervous system activity, while NaCl resistant Wistar-Kyoto (WKY) rats show neither response. Since endogenous ANP may inhibit ganglion transmission, an inability of SHR-S to increase ganglion ANP appropriately in response to high NaCl feeding could contribute to the NaCl induced increase in sympathetic nervous system activity and blood pressure in this model, while an increase in ganglion ANP in NaCl supplemented WKY would tend to prevent sympathetic activity and blood pressure from rising. The current study tested the hypothesis that ganglion ANP levels increase in WKY but not in SHR-S during dietary NaCl supplementation. Male SHR-S and WKY rats were placed on 1% or 8% NaCl diets at 7 weeks of age. The rats were decapitated without prior anesthesia 3 weeks later, and the superior cervical and celiac ganglia were removed for the measurement of ANP by radioimmunoassay. Dietary NaCl supplementation produced significant increases in blood pressure in SHR-S, but not in WKY rats; the high NaCl diet was associated with significant increases in the ANP content of superior cervical and celiac ganglia in WKY rats, but not in SHR-S.(ABSTRACT TRUNCATED AT 250 WORDS)

Extracorporeal liver ablation using sonography-guided high-intensity focused ultrasound

RATIONALE AND OBJECTIVES

High-intensity focused ultrasound (HIFU) is the only radiation beam that can remotely destroy deep-seated tissue targets without causing damage to the intervening tissues. This study evaluates the ability of sonography-guided HIFU to extracorporeally induce liver ablation in a rabbit model.

METHODS

Under sonographic guidance, the HIFU beam was transcutaneously focused at the target tissue in the liver through a subcostal approach. A computer controlled the HIFU exposure and transducer movement to destroy a preselected tissue volume. Simultaneous sonography monitored the tissue response. Ten insonated rabbits were killed from days 0 to 10, and the liver and intervening tissues were examined histologically.

RESULTS

A sharply demarcated sonolesion of coagulation necrosis was produced in the liver in 9 of 10 animals. No damage was found in the intervening tissues (n = 6) when adequate acoustic coupling and proper beam path was applied.

CONCLUSION

Sonography-guided HIFU might be a potential new modality for extracorporeal inducement of liver cancer ablation without resorting to laparatomy.

Novel method to extract large amounts of bacteriocins from lactic acid bacteria

Antimicrobial peptides, bacteriocins, produced by lactic acid bacteria were adsorbed on the cells of producing strains and other gram-positive bacteria. pH was a crucial factor in determining the degree of adsorption of these peptides onto cell surfaces. In general, between 93 and 100% of the bacteriocin molecules were adsorbed at pHs near 6.0, and the lowest (< or = 5%) adsorption took place at pH 1.5 to 2.0. On the basis of this property, a novel isolation method was developed for bacteriocins from four genera of lactic acid bacteria. By using this method we made preparations of pediocin AcH, nisin, sakacin A, and leuconocin Lcm1 that were potent and concentrated. This method produced a higher yield than isolation procedures, which rely on precipitation of the bacteriocins from the cell-free culture liquor. It is simple and can be used to produce large quantities of bacteriocins from lactic acid bacteria to be used as food biopreservatives.

Effects of amino-terminal extensions and specific mutations on the activity of restrictocin

The cytotoxic activities of restrictocin with aminoterminal extensions and specific mutations were investigated using in vivo and in vitro systems. Genes were constructed from the cDNA clone of restrictocin which encode: the native form of restrictocin (including the leader sequence); Met-prorestrictocin, in which a codon for methionine was placed before a putative pro region; Met-mature restrictocin, with a methionine codon prior to the mature form of restrictocin; and three mutated forms of Met-mature restrictocin, E95G, E115G/H136L, and H136L. These constructions were placed under the control of the GAL1 promoter and were transformed into Saccharomyces cerevisiae. Transformants were killed, and a new RNA band formed when any of these genes except those containing the H136L mutation were expressed. Restrictocin protein was detected by immunoblot only in cells expressing the native form of restrictocin and the forms containing the H136L mutation. Native restrictocin, Met-prorestrictocin, and Met-mature restrictocin mRNA were translated in an in vitro system resulting in proteins of the expected molecular weight and inactivation of the translation system. Restrictocin was not inactivated by the presence of the leader sequence and the putative prosequence. Amino acid His136 is putatively in the active site of restrictocin by analogy to ribonuclease U2 and the elimination of toxic effects in the S. cerevisiae expression and in vitro translation systems.

[A research on the quality of radix Astragali]

Milkvetch root (Radix Astragali) and its likes were determined in their contents of trace elements, total extracts and astragalin A. The result showed there was some relationship between the drug quality, trace-element contents, difference of species, growing areas and on-the-spot processing methods.

Salt supplementation does not alter the pressor effect of blocking atrial natriuretic peptide in nucleus tractus solitarii

We have previously shown that microinjection of monoclonal antibody to atrial natriuretic peptide (ANP) into the caudal nucleus tractus solitarii causes a pressor response in salt-sensitive spontaneously hypertensive rats (SHR) fed a basal (1%) salt diet, suggesting that endogenous ANP in this region may be involved in the centrally mediated regulation of blood pressure in this model. The present study tested the hypothesis that the pressor effect of blocking endogenous ANP in caudal nucleus tractus solitarii is enhanced by dietary salt supplementation in salt-sensitive SHR. Monoclonal antibody to ANP (0.55 micrograms) in 50 nl artificial cerebrospinal fluid or control immunoglobulin G was microinjected into the caudal nucleus tractus solitarii of conscious salt-sensitive SHR, salt-resistant SHR, and Wistar-Kyoto rats fed 1% or 8% salt diets for 3 weeks. Microinjection of the monoclonal antibody into the caudal nucleus tractus solitarii evoked similar increases in mean arterial pressure in salt-sensitive SHR on both 1% and 8% salt diets and in salt-resistant SHR on a 1% salt diet but had no effect in Wistar-Kyoto rats. In contrast, microinjection of control immunoglobulin G into this brain area did not alter mean arterial pressure or heart rate in any experimental group. Thus, endogenous ANP in caudal nucleus tractus solitarii mediates tonic control of blood pressure in both salt-sensitive and salt-resistant SHR but not in Wistar-Kyoto rats, and this effect is independent of the salt sensitivity of hypertension and of dietary salt intake.

Regulation of restrictocin production in Aspergillus restrictus

The production of restrictocin (a cytotoxin that specifically cleaves ribosomal RNA) by cultures of Aspergillus restrictus grown in liquid medium was investigated. The function of restrictocin, the method of its accumulation and the mode of resistance to restrictocin in A. restrictus are unknown. Previous studies have indicated that restrictocin accumulates in the medium with culture age. These observations have been extended in this study by cloning the cDNA of the res gene and using this cDNA clone to probe the onset of messenger RNA synthesis in the cells. The results of the Northern analysis were compared to the production and accumulation of restrictocin and morphological differentiation of the cells in culture. Restrictocin was found in the medium at the same time that mRNA was detected in the cells. This suggests that the leader sequence encoded by the cDNA provides an efficient secretion system for the protein. Both the protein and the mRNA were detected coincident with the formation of differentiated cell structures. These structures develop into conidiophores with one layer of sterigmata and conidia forming from the sterigmata. These results suggest that restrictocin is either involved in the process of conidiation or is coordinately regulated with differentiation leading to conidiation.

Effects of acute and chronic blockade of neutral endopeptidase with Sch 34826 on NaCl-sensitive hypertension in spontaneously hypertensive rats

We have previously demonstrated that dietary NaCl supplementation is associated with increased circulating atrial natriuretic peptide (ANP) levels in Wistar-Kyoto (WKY) rats but not in spontaneously hypertensive rats (SHR), and that replacement with exogenous ANP prevents NaCl-sensitive hypertension in NaCl-sensitive SHR (SHR-S). The current study tested the hypothesis that chronic administration of the neutral endopeptidase (NEP) inhibitor Sch 34826 prevents NaCl sensitive hypertension in SHR-S by increasing endogenous ANP. Male SHR-S received Sch 34826 (90 mg/kg/day) or vehicle by gavage for 4 weeks beginning immediately before the initiation of 1% or 8% NaCl diets at age 7 weeks. Sch 34826 prevented the increase in arterial pressure in response to 8% NaCl in SHR-S, but had no effect on blood pressure in 1% NaCl fed SHR-S; plasma ANP levels were increased by 63 and 68% in the 1% and 8% NaCl groups, respectively, in response to Sch 34826. To examine the mechanism(s) of the antihypertensive effect of Sch 34826 in NaCl-supplemented SHR-S, a single dose (90 mg/kg) of Sch 34826 or vehicle was administered by gavage to SHR-S that had consumed 1% or 8% NaCl diets for 3 weeks. Sch 34826 abolished the NaCl-induced increase in blood pressure 3 h after treatment in 8% NaCl fed SHR-S, but had no effect in SHR-S fed the 1% NaCl diet. This effect was associated with increased urine volume and urinary sodium, ANP, and cyclic GMP in 8% NaCl fed SHR-S.(ABSTRACT TRUNCATED AT 250 WORDS)

A reproducible rat liver cancer model for experimental therapy: introducing a technique of intrahepatic tumor implantation

To investigate therapeutic strategies for hepatoma, it is necessary to have a reproducible animal model with a tumor growth pattern allowing accurate assessment of results. Many techniques of intrahepatic tumor implantation (IHTI) have been devised for intrahepatic tumor models. Most of them, however, have the disadvantage of high rates of artificial tumor dissemination during tumor implantation, which interferes with the evaluation of therapy. To overcome this problem, we have developed a technique of IHTI in which a piece of Gelfoam is placed into a small incision in the liver for the purpose of both hemostasis and formation of a tension-free pocket to accept the tumor implant. In 583 ACI rats receiving IHTI with Morris hepatoma 3924A, the tumor take rate was 100%. Resembling the natural course of human hepatoma, the implanted tumor grows locally early in the course of disease and eventually invades the surrounding organs causing ascites and also metastasizes to the lung. Liver microangiography demonstrated that the tumor received blood supply mainly from the hepatic artery. This IHTI technique was also compared to two other methods of IHTI: insertion of fragments without using Gelfoam and implantation with a tumor cell suspension. A significantly lower rate of early lung metastases was achieved with our technique (0%) in comparison with other two techniques (41 and 80%). We conclude that this rat liver cancer model is reproducible and allows efficient evaluation of treatment modalities for liver cancer without interference from tumor at undesirable sites.

A reproducible rat liver cancer model for experimental therapy: introducing a technique of intrahepatic tumor implantation

To investigate therapeutic strategies for hepatoma, it is necessary to have a reproducible animal model with a tumor growth pattern allowing accurate assessment of results. Many techniques of intrahepatic tumor implantation (IHTI) have been devised for intrahepatic tumor models. Most of them, however, have the disadvantage of high rates of artificial tumor dissemination during tumor implantation, which interferes with the evaluation of therapy. To overcome this problem, we have developed a technique of IHTI in which a piece of Gelfoam is placed into a small incision in the liver for the purpose of both hemostasis and formation of a tension-free pocket to accept the tumor implant. In 583 ACI rats receiving IHTI with Morris hepatoma 3924A, the tumor take rate was 100%. Resembling the natural course of human hepatoma, the implanted tumor grows locally early in the course of disease and eventually invades the surrounding organs causing ascites and also metastasizes to the lung. Liver microangiography demonstrated that the tumor received blood supply mainly from the hepatic artery. This IHTI technique was also compared to two other methods of IHTI: insertion of fragments without using Gelfoam and implantation with a tumor cell suspension. A significantly lower rate of early lung metastases was achieved with our technique (0%) in comparison with other two techniques (41 and 80%). We conclude that this rat liver cancer model is reproducible and allows efficient evaluation of treatment modalities for liver cancer without interference from tumor at undesirable sites.

Effects of high-intensity focused ultrasound in the treatment of experimental neuroblastoma

This report evaluates the effect of high-intensity focused ultrasound (HIFU) on subcutaneous murine neuroblastoma C1300. HIFU treatment was administered with a focused 4-MHz quartz transducer with a peak intensity of 550 W/cm2. In experiment 1, 60 animals with tumor were divided into four groups. Group I (n = 15) were controls; group II (n = 15) received adriamycin, 5 mg/kg intraperitoneally; group III (n = 15) received HIFU; and group IV (n = 15) received both adriamycin and HIFU. All the animals in groups I and II died of tumor by 35 days. Fifty-three percent (8/15) of mice in group III and 80% (12/15) in group IV were cured with no evidence of tumor (NET) at 200 days. Log-rank statistics showed significant prolongation of survival in the groups III and IV as compared with groups I or II (P less than .05). In experiment 2, 45 animals with tumor were divided into three groups. Group I (n = 15) were controls; group II (n = 15) received HIFU; and group III (n = 15) received repeated HIFU. The results showed 47% (7/15) of mice in group II and 67% (10/15) in group III were NET at 200 days. Significant survival prolongation was achieved in groups II and III in comparison with group I (P less than .05). In experiment 3, 90 mice received either tumor (n = 60) or saline (n = 30) inoculation in the left flank. On day 5, 45 mice with tumor were treated with HIFU (group I), while the other 15 mice with tumor (group II) had a sham procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatic artery ligation and infusion chemotherapy for unresectable primary liver cancer

During the period of 1958-1989, 356 patients with pathologically proven primary liver cancer (PLC) were determined by laparotomy to be unresectable. Of the 356 patients, 51 (14.3%) were of subclinical stage, 287 (80.6%) of moderate stage and 18 (5.1%) of late stage. The association of liver cirrhosis was present in 310 patients (87.1%). Treatment modalities in 356 patients were divided into 4 groups: hepatic artery ligation (HAL) (51), hepatic artery infusion (HAI) of chemotherapeutic agents (114), HAL + HAI (117), and HAL + HAI + radiotherapy (74). The 5-year survival rate was zero in the 4 groups in the period of 1958-1977. During 1978-1989, however, the 5-year survival rate was zero in HAL, 7.9% in HAI, 24.4% in HAL + HAI (with second look resection in 10 patients), and 36.5% in HAL + HAI + radiotherapy (with second look resection in 19). The marked improvement in survival in later period was attributable to the accurate site of hepatic artery catheter, longer infusion chemotherapy, and combination treatment, particularly second look resection in some of the patients. These results indicate that HAL + HAI + combination treatment might provide a possible prolongation of survival or even resection in some patients with original unresectable PLC.

High-intensity focused ultrasound in the treatment of experimental liver cancer

High-intensity focused ultrasound (HIFU) was used to treat Morris rat hepatoma 3924A implanted in the liver. Treatment was administered with a lens-focused 4-MHz transducer that created a focused beam of 550 W/cm2 at peak intensity. One hundred twelve rats with liver tumors were divided into two groups of 56 each. Group 1 received HIFU therapy while group 2 (the control group) did not. All rats were killed immediately or 1, 3, 7, 14, 21, or 28 days after treatment. Eight rats in each group were killed at each interval for pathologic and biochemical studies. Significant inhibition of the tumor growth was seen in the HIFU-treated group, with tumor growth inhibition rates of 65.4% to 93.1% from the third to the 28th day after treatment. Ultrasound-treated tumors showed direct thermal cytotoxic necrosis and fibrosis. An additional 56 ACl rats with liver tumors were divided into four groups of 14 each. Group 1 received doxorubicin hydrochloride intraperitoneally and HIFU therapy; group 2, HIFU therapy; group 3, doxorubicin hydrochloride; and group 4 (the control group), neither HIFU nor doxorubicin hydrochloride. Significantly improved survival rates were noted in HIFU-treated animals (groups 1 and 2) compared with those of groups 3 and 4. These data suggest that HIFU may be a useful method for local treatment of hepatic tumors.

Impaired hepatic bacterial clearance is reversed by surgical relief of obstructive jaundice

Sepsis is a major cause of morbidity and mortality in infants with cholestatic jaundice. Previous studies have shown that biliary obstruction in rats causes a significant decrease in hepatic phagocytosis of viable Escherichia coli. This study tests this hypothesis and further evaluates whether the impaired function of the reticuloendothelial system of the liver (Kupffer cells) can be reversed by the relief of the biliary obstruction. Male Sprague-Dawley rats (weighing 140 to 150 g) were placed in three groups. Group I (n = 10) consisted of sham-operated controls. In Group II (n = 30), ligation and division of distal common bile duct (CDL) was performed. Group III (n = 30) underwent choledochoduodenostomy 2 weeks following ligation and division of common bile duct. At 1, 2, and 3 weeks following the operation, 10(9) 35S-radiolabeled viable E coli were injected intravenously via the tail vein. At 10 minutes, bacterial distribution in the liver, spleen, kidneys, and lungs was determined. Tissue samples (50 to 100 mg) from each organ were processed for liquid scintillation counting. The final distribution of bacteria was calculated from the input specific activity (dpm/bacteria) and expressed as the mean percentage of injected viable E coli per gram of tissue and per total organ weight. There was a significant decrease in the trapping of bacteria by the liver's Kupffer cells in rats in group II, at 2 and 3 weeks following CDL (45.0% +/- 14.0% and 15.1% +/- 4.9%, respectively, v controls 75.9% +/- 13.7%; P less than .005).(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinogenesis studies in rodents for evaluating risks associated with chemical carcinogens in aquatic food animals

Fish and shellfish caught in polluted waters contain potentially dangerous amounts of toxic and carcinogenic chemicals. Public concern was heightened when a large percentage of winter flounder taken from Boston Harbor was found to have visible cancer of the liver; winter flounder outside the estuary area had no liver lesions. Long-term chemical carcinogenesis studies could be easily and feasibly designed using laboratory rodents offered diets containing fish caught in polluted waters. Induced cancers in rodents would corroborate field observations in fish; positive results from these studies would provide further evidence about potential human health hazards from eating substantial amounts of chemically contaminated fish. Nonetheless, fish and aquatic organisms should be viewed as environmental biological monitors of pollution or of potential human health hazards, and authorities responsible for assuring clean and safe rivers, bodies of water, and biota should give more attention to these valid biological indicators or sentinels of environmental pollution. Consequently, fish and other sea creatures alone should serve as alarms regarding whether water areas constitute public health hazards.

Direct visualization of phosphorylase-phosphorylase kinase complexes by scanning tunneling and atomic force microscopy

In skeletal muscle the activation of phosphorylase b is catalyzed by phosphorylase kinase. Both enzymes occur in vivo as part of a multienzyme complex. The two enzymes have been imaged by atomic force microscopy and the results compared to those previously found by scanning tunneling microscopy. Scanning tunneling microscopy and atomic force microscopy have been used to view complexes between the activating enzyme phosphorylase kinase and its substrate phosphorylase b. Changes in the size and shape of phosphorylase kinase were observed when it bound phosphorylase b.

Scanning tunneling microscopic images show a laminated structure for glycogen molecules

Scanning tunneling microscopy (STM) has been used to examine glycogen molecules. Individual molecules were approximately ellipsoidal with dimensions in the 20- to 60-nm range. Images of the glycogen molecular surfaces have a laminar appearance. The layered features seen on the surfaces of the molecules suggest that glycogen may grow from one edge as a laminar structure to form an ellipsoid rather than originating at a central point with radial growth of the oligosaccharide chains to form a sphere. The results of these studies indicate that STM can be used to determine details of polysaccharide structures.

Scanning tunneling microscopy of the enzymes of muscle glycogenolysis

Scanning tunneling microscopy (STM) has been used to examine the structures of the skeletal muscle enzymes phosphorylase and phosphorylase kinase. The interaction of these two proteins represents the last step in the process of signal transduction which results in muscle glycogen being converted into metabolic energy for use in muscle contraction. Phosphorylase b has a molecular weight of 97,000 and the dimer is seen by STM to have dimensions of 11 X 5.7 nm. Phosphorylase b has a tendency to form linear arrays of dimers on the graphite surface used as the support for STM imaging. Phosphorylase kinase is imaged as a butterfly-like object with lateral dimensions of 36 X 27 nm. The molecular thicknesses given by scanning tunneling microscopy for these two non-conducting molecules is significantly less than expected. The height measurement in STM is dependent not only on the surface topology of the object being imaged, but also on the electronic work function of the object compared to that of the graphite surface on which it lies. In addition to the individual proteins, a complex between phosphorylase and phosphorylase kinase has been observed by scanning tunneling microscopy.

Adequacy of disposable biopsy forceps for gastrointestinal endoscopy: a direct comparison with reusable forceps

Disposable plastic biopsy forceps were compared prospectively to reusable stainless steel forceps. Thirty consecutive patients underwent a total of 249 biopsies, 124 with the disposable forceps, and 125 with reusable forceps. Biopsy locations included the esophagus, stomach, small intestine, colon, and common bile duct. Specimens were compared microscopically to determine overall surface area, depth, adequacy, and diagnostic result. The disposable biopsy forceps yielded specimens which were 37% smaller when compared with the reusable forceps. In five of the comparisons, minor differences in histological findings were noted between the two groups of biopsy specimens, but these differences did not alter the pathological diagnosis. However, in three cases in which superficial specimens were obtained, an underlying carcinoma was missed with the disposable forceps. Our study documents the utility of disposable biopsy forceps for mucosal lesions. In addition, there were 11 mechanical failures in 38 biopsy attempts with the plastic biopsy forceps. These forceps appear to be limited in their capacity to obtain adequate specimens from firm tissue or when submucosal biopsy samples are required, and they will require refinements in design to duplicate specimen quality obtained by traditional reusable forceps. Disposable forceps are particularly suitable for biopsy of mucosal lesions in patients with possible communicable disease, and they should help to reduce cross-contamination in the gastroenterology laboratory.

[Clinical analysis of 418 patients with Wilson's disease in traditional Chinese medicine and Western medicine therapy]

From 1974 to 1988, 418 cases of Wilson's disease were treated with TCM-WM in our hospital. 147 cases were of Wilson's type; 149 cases were of pseudosclerosis type; 40 cases were of abdominal and hepatocerebral type; 21 cases were of choreoathetosis type and 21 cases of other types. After a course of treatment for 3 to 6 months, 103 patients showed marked improvement and 286 made some improvement, but no effect was found in 22 patients and 7 deaths were observed. The results were as follows: (1) The mortality in the severe and moderate groups were significantly higher than the mild (P less than 0.05) and the marked effective rate was less than the latter (P less than 0.01). (2) The marked effective rate was lower in abdominal and hepatocerebral type, and no significant difference was found in recovery rate between Wilson's type and pseudosclerosis type.

Radioimmunotherapy in the multimodality treatment of hepatocellular carcinoma with reference to second-look resection

Experimental study using nude mice human hepatocellular carcinoma (HCC) xenograft indicated that the combination treatment with iodine 131 (131I)-anti-human HCC isoferritin (131I-isoFtAb), cisplatin, and mixed bacterial vaccine (MBV) yielded better inhibition rate as compared with double combination or 131I-isoFtAb alone. Based on these findings, 25 patients with surgically proven nonresectable and pathologically proven HCC have been treated by radioimmunotherapy using 131I-isoFtAb intrahepatic arterial infusion as a part of multimodality treatment. Of the 25 patients, seven (28.0%) received second-look resection after marked shrinkage of tumor. The 1-year survival was 52.5% (12/23) and 2-year survival 27.7% (five of 18) in the entire series. Of the five patients with 2-year survival, four were in the second-look resection group. Patients with tumor less than or equal to 8 cm showed higher second-look resection rate (62.5% versus 11.8%) and 1-year survival (85.7% versus 37.5%) as compared with tumor greater than 8 cm. Mixed bacterial vaccine as adjuvant immunotherapy seemed effective to prolong survival. The 2-year survival was higher in patients with second-look resection as compared with those without (75.0% versus 14.3%). Thus, radioimmunotherapy using 131I-isoFtAb might be one of the modalities of choice, particularly in the conversion of nonresectable to resectable HCC in a well-designed multimodality treatment regimen.

Surgery of small hepatocellular carcinoma. Analysis of 144 cases

A long-term follow-up study of 144 cases with surgically and pathologically proved small hepatocellular carcinoma (less than or equal to 5 cm) from 1967 to 1987 is reported. One hundred eight cases (75.0%) were detected by alpha-fetoprotein serosurvey and/or ultrasonography mainly in a high-risk population; 129 cases (89.6%) coexisted with cirrhosis. Resection was done in 132 cases (91.7%) with three (2.3%) operative deaths; cryosurgery, laser vaporization, and hepatic arterial chemotherapy were used in the rest. Limited resection was done in 67.4% of resections. Reresection of subclinical recurrence or solitary pulmonary metastasis was done in 21 cases. The 5-year and 10-year survival rates were 67.9% and 53.4% in the resection group but zero in the nonresection group. Survival was correlated negatively with tumor size, 5-year survival after resection was 84.6% in tumors less than or equal to 2 cm but 59.5% in tumors of 4.1 to 5 cm. The increase of resectability and reresection resulted in marked improved of 5-year survival from 43.5% in 1973 to 1977 to 63.3% in 1978 to 1982 in the entire series. No significant difference was found between survival of limited resection and lobectomy. Resection may be the modality of choice for treatment of small hepatocellular carcinomas with compensated liver function. Limited resection instead of lobectomy was the key to increased resectability and decreased operative mortality in cirrhotic livers. Reresection of subclinical recurrence was important to prolong survival further.

Surgery of small hepatocellular carcinoma. Analysis of 144 cases

A long-term follow-up study of 144 cases with surgically and pathologically proved small hepatocellular carcinoma (less than or equal to 5 cm) from 1967 to 1987 is reported. One hundred eight cases (75.0%) were detected by alpha-fetoprotein serosurvey and/or ultrasonography mainly in a high-risk population; 129 cases (89.6%) coexisted with cirrhosis. Resection was done in 132 cases (91.7%) with three (2.3%) operative deaths; cryosurgery, laser vaporization, and hepatic arterial chemotherapy were used in the rest. Limited resection was done in 67.4% of resections. Reresection of subclinical recurrence or solitary pulmonary metastasis was done in 21 cases. The 5-year and 10-year survival rates were 67.9% and 53.4% in the resection group but zero in the nonresection group. Survival was correlated negatively with tumor size, 5-year survival after resection was 84.6% in tumors less than or equal to 2 cm but 59.5% in tumors of 4.1 to 5 cm. The increase of resectability and reresection resulted in marked improved of 5-year survival from 43.5% in 1973 to 1977 to 63.3% in 1978 to 1982 in the entire series. No significant difference was found between survival of limited resection and lobectomy. Resection may be the modality of choice for treatment of small hepatocellular carcinomas with compensated liver function. Limited resection instead of lobectomy was the key to increased resectability and decreased operative mortality in cirrhotic livers. Reresection of subclinical recurrence was important to prolong survival further.

Direct observation of phosphorylase kinase and phosphorylase b by scanning tunneling microscopy

The molecular structures of phosphorylase b and phosphorylase kinase have been visualized by scanning tunneling microscopy (STM). STM is a near field technique that can resolve structures at the nanometer level and thus can image individual molecules. Phosphorylase b can be seen in dimeric and tetrameric forms as well as linear and globular aggregates. The linear arrays consist of side by side dimers with the long axis of the dimer perpendicular to the aggregated chain. Individual molecules of phosphorylase kinase appear to be planar, bilobate structures with a 2-fold axis of symmetry and a central depression.

Herpesviridae in the coronary arteries and aorta of young trauma victims

The presence of herpes simplex virus (HSV) and cytomegalovirus (CMV) nucleic acid and/or antigen was demonstrated in the coronary arteries and thoracic aortas of young trauma victims by the in situ DNA hybridization and ABC immunoperoxidase methods, respectively. Epstein-Barr virus (EBV) nucleic acid and capsid antigen were not detected in the arteries sampled in this study. Of 8 subjects in which virus was detected in the coronary arteries, 6 were positive for HSV and 2 for CMV; of 7 cases positive in the thoracic aorta, 5 were identified as HSV and 2 as CMV. Viral DNA and/or antigen were found in occasional cells in the intact luminal surface and in focal clusters of spindle-shaped or "foamy" cells in the intimal layer. The histologic findings indicate that HSV and CMV are associated with areas showing early or advanced atheromatous changes in the coronary arteries and with lesion-free as well as lesion areas in the thoracic aorta. The virologic findings support the concept that herpes-viruses may potentially play a direct or indirect role in the pathogenesis of human atherosclerosis.

[Misdiagnosis of malignant lymphoma--report of 45 patients]

A series of 50 patients with malignant lymphoma, proven by biopsy, was retrospectively studied. 39 were non-Hodgkin's lymphoma and 11 Hodgkin's disease. 45 (90%) had been misdiagnosed because of lack of initial specific symptoms. It is suggested that for patients with a painless progressively enlarging superficial lymph node without adhering to its surrounding tissues and irresponsive to general management, having irregular fever, bloody stool, abdominal pain or mass, complication of partial intestinal obstruction, sharp vigilance be kept for the possibility of malignant lymphoma.

Hypoxia-induced inhibition of converting enzyme activity: role in vascular regulation

Systemic and pulmonary vascular reactivity to graded doses of angiotensin I (ANG I), angiotensin II (ANG II), and, as a control, phenylephrine were examined in 14- or 28-day hypoxia-exposed and air control rats. Hypoxic rats exhibited pulmonary hypertension that was reversible on return to room air, but systemic arterial pressure was not altered by hypoxia. Systemic pressor responses to ANG I and ANG II were significantly less in the hypoxic rats than in the control rats at 14 and 28 days but returned to control levels in hypoxic animals that were then returned to room air, demonstrating reversibility of the hypoxia-induced changes in vascular reactivity. Pulmonary pressor responses to ANG I were significantly less at 14 days, whereas responses to ANG II were significantly greater at 28 days, in hypoxic rats than in controls. There were no significant differences in systemic and pulmonary pressor responses to phenylephrine between the hypoxic and air control animals. The altered systemic and pulmonary pressor responsiveness to ANG I and ANG II in hypoxic rats is probably related to mechanisms specific to the renin-angiotensin system, such as inhibition of intrapulmonary angiotensin-converting enzyme activity and down regulation of ANG II receptors in the systemic circulation. Further study is needed to elucidate these mechanisms.

Approximate formulas for the microbending loss in single-mode fibers

Some approximate formulas for calculating the microbending loss for single-mode fibers are given. The formulas are rather simple, yield good approximate values, and hence can be used to evaluate the microbending loss in fiber design.