Tetrazolium-based cell bioassay for neurotoxins active on voltage-sensitive sodium channels: semiautomated assay for saxitoxins, brevetoxins, and ciguatoxins

In the present study we have developed an assay for the detection of sodium channel-specific marine toxins based upon mitochondrial dehydrogenase activity in the presence of veratridine and ouabain. This cell bioassay allows detection of either sodium channel enhancers, such as the brevetoxins and the ciguatoxins, or sodium channel blocking agents, such as the saxitoxins. The assay responds in a dose dependent manner and differentiates the toxic activity as either sodium channel blocking or enhancing. In addition, the assay is highly sensitive, with present detection limits of 2 ng/ml for either saxitoxins or brevetoxins (PbTx-1 and PbTx-3). Assay response to a ciguatoxic extract and to brevetoxins is rapid, allowing dose dependent detection within 4 to 6 h. The method is simple, utilizes readily available reagents, uses substantially less sample than required for mouse bioassay, and is well within the scope of even modest tissue culture facilities. This cell-based protocol has the potential to serve as an alternate and complementary method to the standard mouse bioassay.

Detection of specific serum IgE in clonorchiasis cases and analysis of Clonorchis sinensis allergens

Specific serum IgE levels of Clonorchis sinensis in infected humans were measured by avidin-biotin ELISA, and allergens from C. sinensis were identified by immunoblot and autoradiography. Then, allergens fractionated by Sephadex G-200 gel filtration were analyzed, and cross-reactive allergenic components of C. sinensis reacted with paragonimiasis sera were revealed. Fourteen out of 15 C. sinensis egg-positives were found to be serum IgE positive (absorbance > 0.27). Of 14 IgE-reacting allergen bands visualized, major allergens of 66, 61.5, 45, 37, 28.5, 23.5 and 15.5 KD were recognized by more than 50% of the sera of infected humans. The considerable individual variations of IgE immune responses to C. sinensis allergenic components were also noticed. C. sinensis extract was separated into 5 fractions by Sephadex G-200 gel filtration. Seventy-four KD allergen was recognized in the first fraction, 50, 45, 37, 29.5 and 28.5 KD in the third, and 15.5 KD in the fourth. Cross-reactive allergens with sera of paragonimiasis cases were identified as 66, 45, 28.5, 13 and 7.5 KD.

High level expression in Saccharomyces cerevisiae of an artificial gene encoding a repeated tripeptide aspartyl-phenylyalanyl-lysine

A chemically synthesized gene, which encodes a 64 or 128 times-repeated tripeptide, aspartyl-phenylalanyl-lysine, has been cloned onto the yeast expression vector pAM82 containing the PHO5 promoter. The artificial gene (LAP gene) contains the untranslated leader sequence of the E. coli lipoprotein gene (lpp) with its transcription terminator sequence. When yeast AH22 cells transformed by recombinant plasmid containing repeated tripeptide gene were derepressed in low phosphate medium, the artificial polypeptides were synthesized to the amounts of about 30% of the total cell protein. SDS-polyacrylamide gel electrophoresis and immunoblot analysis indicated that the artificial polypeptides synthesized in yeast have molecular weights ranging from about 30,000 and 60,000 and have immunoreactivity with the artificial polypeptides expressed in E. coli. The artificial popypeptides in whole cell extract were insoluble and seem to be synthesized as insoluble aggregates. Electron microscopy showed the presence of inclusion bodies in the cell. These polypeptides can be hydrolyzed to tripeptides with trypsin or chymotrypsin. These properties along with the high expression and easy separation may make the artificial polypeptides a potential raw material for the production of an artificial sweetener, Aspartame.

Consequences of rapid fertility decline in the Republic of Korea: issues and solutions

During the last 3 decades, efforts to deal with population problems in Korea have focused largely on reducing population growth. The national population control program has been a major means of achieving this goal. Between the early 1960s and 1990, evidence from a national survey indicates that the percent of current use of contraception rose from about 12% to 80% and the total fertility rate fell to 1.6. representing 1 of the most rapid fertility transitions in the developing world. In conjunction with this rapid reduction in fertility, mortality also improved significantly during this period. Thus, Korea has virtually completed the demographic transition from high birth and death rates to low birth and death rates during the same period. It is widely recognized that Korea has reached demographic maturity and has also achieved remarkable economic development at the same time. The world's demographic history shows that the demographic transition which almost every industrialized country has gone through from a predominantly rural, illiterate society with high birth and death rates, to a predominantly rural, illiterate society with high birth and death rates, to a predominantly urban, educated society with low birth and death rates usually takes well over a century, but in Korea, that process has taken only a few decades. On the other hand, the consequences of a rapid fertility decline bring about various demographic and social issues which we have to take into consideration for future socioeconomic development policy concerning the well-being of the Korean people. Some of issues for policy consideration can be broadly summarized as follows: 1) gradual imbalance of sex ratio at birth due to traditional son preference behavior; 2) latent effect of inevitable population aging and increasing dependency burden on behalf of the elderly for the public sector; 3) changes in family life cycle and rapid transformation form a large to a small family; 4) increasing demand for now social roles for women, supported by easing of child care burdens within households.

[Worm recovery rate and small intestinal lesions of albino rats coinfected with Fibricola seoulensis and Metagonimus yokogawai]

Worm recovery rates and pathologic changes in small intestine of albino rats were observed after concurrent and challenge infections with metacercariae (MC) of Fibricola seoulensis and Metagonimus yokogawai, and compared with those of single infection groups. Albino rats in concurrent infection group were killed 20 days after feeding with 1,000 MC of each fluke. Rats in challenge infection group were fed with 1,000 MC of F. seoulensis and challenged by 1,000 MC of M. yokogawai 10 days after primary infection, then killed 10 days thereafter. In concurrent infection group, mean number of F. seoulensis and M. yokogawai recovered, 250 and 118 respectively, were similar to those of single infection groups. However, more flukes were collected from the duodenum and less flukes were from the ileum than from single infection group. In challenge infection group, the recovery rate of F. seoulensis was similar to that of single infection group and the distribution of the flukes was similar to that of concurrent infection group. Mean number of M. yokogawai, 69, was significantly lower than that of single infection group. Its distribution, however, extended to the duodenum and most of the flukes were recovered from the jejunum. In concurrent infection group, villi of the duodenum were more markedly thickened, fused and shortened than those in F. seoulensis single infection group. The crypt epithelium appeared to be hyperplastic and inflammatory cell infiltration into the villous stroma was mild. Villous atrophy in the jejunum and ileum was milder than in M. yokogawai single infection group. In challenge infection group, the findings were similar to those of concurrent infection group.(ABSTRACT TRUNCATED AT 250 WORDS)

Partial patellectomy for patellar fracture: tension band wiring and early mobilization

Partial patellectomy for patellar fracture was performed in 56 patients. The patellar tendon-to-bone repair was reinforced by a figure-of-eight tension band wire loop from the patella down to the tibial tubercle. Early mobilization and weight bearing of the injured extremity was initiated within the first postoperative week. Thirty-one patients treated between 1977 and 1980 were reviewed retrospectively at an average of 22 months (range 3-49 months). Twenty-five patients treated between 1984 and 1987 were studied prospectively: Knee function was monitored at 5.5 weeks after injury, at 3 months, and at final follow-up at a mean of 25 months (range 8-48 months). Satisfactory knee function was recovered by 3 months. No disruption of knee extensor mechanism was encountered. Complications were frequent in the retrospective series. A high percentage of patients had radiological osteoarthritis after the fracture. This could be due to alteration of the patellofemoral articulation after part of the patella was excised.

Malignant fibrous histiocytoma of the limbs

Between June 1985 and May 1990 we treated 12 patients with malignant fibrous histiocytoma (MFH) of the limbs by a combination of wide excision and adjuvant radiotherapy. The Enneking surgical staging was II in 11 cases and III in 1. There were 6 women and 6 men, with an average age of 54 years. The leg was involved in 8 patients and the arm in 4. Limb salvage was achieved in 10 patients and amputation was performed in 2. All received adjuvant radiotherapy, with an average of 51.5 Gy. In 6 patients adjuvant CYVADIC chemotherapy was administered for an average of 4 cycles. In the other patients this treatment was not tolerated. Local recurrence occurred in 2 patients and metastases to the lung were seen in a further 2. At an average follow-up of 41.3 months, the Kaplan-Meier estimation of 5 year survival was 87.5%, with a 5 year continuous disease-free survival rate of 66.7%.

Cellular retinol-binding protein and cellular retinoic acid-binding protein in the lacrimal gland

Cells that require or metabolize vitamin A contain cellular retinol-binding proteins (CRBP) and cellular retinoic acid-binding proteins (CRABP) which apparently participate in metabolism and transport of retinoids within the cell. Since the lacrimal gland secretes and metabolizes vitamin A, the cellular retinoid-binding proteins and their mRNAs should also be present in this gland. Total RNA from rat and rabbit lacrimal glands was analysed by RNase protection using 32P-labeled antisense cRNA probes. CRBP-I mRNA is present in rat lacrimal gland at 2% of the level in liver but CRBP-I mRNA could not be identified conclusively in rabbit lacrimal gland using the available rat cRNA probe. CRABP-I mRNA is present in rat lacrimal gland at 5% of the level in the 12-day gestation rat fetus, but was not detectable in the rabbit lacrimal gland. Rabbit or rat lacrimal gland cytosol was incubated with [3H]retinol or [3H] retinoic acid followed by ion-exchange chromatography using a Tris buffer and NaCl gradient. CRBP is present in rabbit and rat lacrimal gland at 78.5 +/- 14.5 and 71.1 +/- 11 pmol g-1 protein, respectively. CRABP is present in rat lacrimal gland at 190.6 +/- 13.8 pmol g-1 protein but was not detectable in rabbit lacrimal gland. The presence of CRBP in the lacrimal gland is consistent with its role in secretion of retinol into the lacrimal gland fluid. The apparent lack of CRABP in rabbit lacrimal gland as compared with rat suggests species differences in the role of retinoids in differentiation and maintenance of this organ.

Determination of plasmid copy number and stability in Clostridium acetobutylicum ATCC 824

The copy number and stability of several plasmid vectors in Clostridium acetobutylicum ATCC 824 were determined. The protocols were modified from the traditional ones to overcome the problems associated with unusual behavior of C. acetobutylicum cells on solid medium. The plasmid copy numbers of pSYL2, pFNK1, pFNK3, and pFNK5 in strain ATCC 824 were 14, 8, 6, and 6, respectively. pSYL2 and pFNK1 were segregationally stable, since the fractions of plasmid-carrying cells after 60 generations of growth without antibiotic (erythromycin) were 73% and 77%, respectively. Vector pFNK1 carrying fermentative genes was found to be rather unstable. The observed instability seemed to be due to the complex host-plasmid interactions by amplified expression of enzymes involved in the tightly regulated primary metabolism of C. acetobutylicum.

Pathological responses to preoperative high-dose methotrexate chemotherapy in osteosarcoma--experience in Korea cancer hospital

During the last decade, many clinical investigators at various cancer centers have reported the efficacy of various chemotherapeutic agents in the treatment of osteosarcoma. The regimens using high-dose methotrexate (HDMTX) with citrovorum factor rescue are now considered to be one of the most effective treatments of choice. From December 1989 to May 1991, sixteen patients with Enneking's stage (Enneking et al., 1980) IIB osteosarcoma of the extremities were treated with a high-dose methotrexate regimen. After two cycles of preoperative chemotherapy, an operation was performed; either limb salvage or amputation. The resected lesions were examined pathologically and classified according to Huvos' criteria. On pathological examination, 8 (50%) cases showed Grade IV; 1 (6.25%) Grade III; 4 (25%) Grade II; and 3 (18.75%) Grade I. The types of surgery performed were tumor prosthesis replacement (11); wide resection with or without reconstruction (2); resection and arthrodesis (1); and amputation (2).

Zinc absorption in experimental osmotic diarrhea: effect of long-chain fatty acids

The effect of free fatty acids on zinc absorption was studied in a rat model of chronic osmotic diarrhea induced with magnesium citrate and phenolphthalein. In vivo rates of zinc removal from the lumen and analysis of tissue for zinc uptake and metallothionein alterations were monitored. One mmol/L stearate enhanced zinc absorption in rats with or without diarrhea, from 207 +/- 22 and 353 +/- 13 pmol/min x cm to 676 +/- 34 and 610 +/- 26 pmol/min x cm, respectively. Palmitate was only effective in normal rats. Zinc absorption inversely correlated with mucosal zinc content in the perfused intestinal segments, in both type of rats. Hepatic metallothionein was enhanced by zinc and even more by oleate plus zinc in both groups; kidney metallothionein in animals with diarrhea was normalized by either oleate or zinc. The data support previous reports on the effect of long-chain fatty acids on the enhancement of zinc absorption: saturation and a longer chain appear to be positive factors. A membrane modification role of long-chain fatty acids could have nutritional implications in the formulation of special diets.

Mucosal tenting suture with stenting in the treatment of chronic laryngotracheal stenosis

A surgical technique of laryngotracheoplasty with long-term stenting was employed exclusively in the treatment of 105 patients with laryngotracheal stenosis in the Department of Otolaryngology, National Taiwan University Hospital from May 1977 to April 1989. The results were satisfactory, 92% of the treated patients being decannulated. The technique of laryngotracheoplasty can be summarized as follows: (1) Exposure of the stenotic region by laryngofissure, anterior and/or posterior cricoid splitting, vertical tracheal incision; (2) debridement of infected soft tissue; (3) relaxation or displacement of heavy scar tissue; (4) placement of sutures to tent the laryngotracheal mucosal remnants to the extraluminal region; (5) insertion of a endolaryngotracheal stent using a silicone T tube; (6) closure of the skin layer of the surgical wound only, without approximating the soft tissue layer between the T tube and skin; and (7) leaving the stent in place for at least 6 months.

Vector construction, transformation, and gene amplification in Clostridium acetobutylicum ATCC 824

In order to alter the primary metabolism of C. acetobutylicum, we have constructed E. coli- or B. subtilis-C. acetobutylicum shuttle vectors that could be used to deliver homologous fermentative genes into C. acetobutylicum ATCC 824. The plasmid copy number and plasmid stability in C. acetobutylicum for several of these plasmids were determined. We have also developed a protocol for the electrotransformation of C. acetobutylicum ATCC 824. Difficulty in the transformation of C. acetobutylicum ATCC 824 with vectors containing DNA from E. coli plasmids was found to be due to the existence of a restriction system in this strain. This type II restriction endonuclease, named Cac824I, recognizes the sequence 5'-GCNGC-3' and cuts ColE1 plasmids frequently. One of the vectors, pFNK1, possessing a variety of unique cloning sites was used in the amplification of one acid (PTB) and one solvent (AADC) formation gene. The corresponding enzyme activities were amplified in C. acetobutylicum as shown by enzyme assays and SDS-PAGE gels of cell extracts.

Preparation of monoclonal antibodies against acid alpha-D-glucosidase for study of Chinese glycogenosis type II patients

Two monoclonal antibodies (Mabs), 8-23 and 4-6, against human acid alpha-D-glucosidase were generated to analyse the intracellular alpha-D-glucosidase from seven Chinese Pompe's disease families with the following study design: [1] Purified alpha-D-glucosidase from normal human urine was used as antigen for immunization of mice. [2] The splenic cells of immunized mice were isolated and fused with myeloma cells NS-1 for generation of hybridomas and production of anti-human alpha-D-glucosidase Mabs and detection of presence of the enzyme in skin fibroblasts obtained from the Pompe's disease families and normal controls. [3] Functional assay of acid alpha-D-glucosidase was done. Both generated Mabs were IgG1 with a kappa light chain. Mabs 8-23 and 4-6 can recognize 70 kd (kilodaltons) alpha-D-glucosidase evidenced by radioimmunoprecipitation (RIP). Our results showed that alpha-D-glucosidase did exist in the skin fibroblasts of all seven Pompe's disease patients by RIP and in the hepatic cells by immunohistological study. However, functional assay of alpha-D-glucosidase of the seven patients with Pompe's disease showed that the enzyme function of alpha-D-glucosidase was defective. This finding is at variance with the results of other workers which indicated that the amount of mature enzyme was reduced or totally absent in most of the juvenile and adult Caucasian and South African patients. The discordance may imply that the cause of alpha-D-glucosidase deficiency in Chinese patients is quite different from that in Caucasian and South African patients. This needs further study to clarify.

Distinct mechanisms of zinc uptake at the apical and basolateral membranes of caco-2 cells

Zinc uptake mechanisms at the apical and basolateral membrane borders of caco-2 cells were examined. This human-derived cell line possesses many morphological and functional characteristics of absorptive small intestinal cells. By day 14, confluent and well-differentiated monolayers were formed when the cells were grown on porous polycarbonate filters. Labelled zinc was placed on the apical or basal side of the monolayer and its uptake by the cells, as well as its transport across the monolayer, were measured. Zinc uptake by the cells from the apical side was found to be a saturable process (Kt = 41 microM; Vmax = 0.3 nmols/cm2/10 min) with a diffusional term at higher concentrations (1.0 sec/cm). Apical uptake was not affected by metabolic inhibitors or potential zinc ligands. Zinc uptake from the basolateral side was concentration dependent (Kd = 1.3 sec/cm) and was partially inhibited (30%) by ouabain and vanadate, suggesting that the (Na-K)-ATPase on the basolateral membrane is involved in the serosal uptake of zinc by the cell. Transport of zinc across the monolayers from the apical or basolateral compartment was concentration dependent and was not affected by metabolic inhibitors. Zinc transport from the basolateral side was greater than 2-fold greater than apical transport. Hence, separate mechanisms can be distinguished with respect to zinc uptake at the apical and basolateral membranes of caco-2 cells.

The lacrimal gland synthesizes retinol-binding protein

The rabbit lacrimal gland secretes retinol bound to a 20-21 kDa protein. To test the hypothesis that this protein might be retinol-binding protein (RBP) we probed lacrimal gland for RBP mRNA and lacrimal gland fluid for RBP. A rabbit RBP cDNA clone was used to probe rabbit and rat lacrimal gland RNA using RNase protection analysis. The lacrimal gland contains RBP mRNA at a level 0.1 to 0.03% of that observed in the liver. This RBP mRNA was identical to that observed in the liver based on RNase protection analysis, Northern blot analysis and primer extension analysis. The RBP mRNA levels in the lacrimal gland were not altered by the retinol status of the rabbits. We analysed lacrimal gland fluid for RBP by immunoblotting using a monoclonal antibody that recognizes rat, human and rabbit RBP. A single protein band from the rabbit lacrimal fluid bound the antibody, and this protein comigrated with human RBP which also bound the antibody. We conclude that the lacrimal gland contains RBP mRNA and that the lacrimal gland synthesizes and secretes RBP into the lacrimal gland fluid. This is the first demonstration that an extrahepatic tissue containing RBP mRNA synthesizes and secretes the protein in vivo.

Transkinetoplastidy--a novel phenomenon involving bulk alterations of mitochondrion-kinetoplast DNA of a trypanosomatid protozoan

Dramatic and consistent changes of mitochondria or kinetoplast DNA (kDNA) were observed in certain variants of Leishmania amazonensis (A variants) selected in vitro for arsenite-resistance. This was found initially by comparing different lots of wild-type cells and their respective A variants resistant to 30 microM arsenite. The kDNAs isolated from these two groups had different restriction patterns and hybridized poorly to each other, whereas those from different lots within each of the two groups were identical. Hybridization data showed an overall identity of less than 10(-3) between total kDNAs of the two groups. This difference was further examined in three independent series of variants, which were selected from three different clones for resistance to graded concentrations of arsenite (5-50 microM). In all three series, their kDNAs were found to change abruptly in an identical pattern at a late step of the selection process, i.e., A variants resistant to 15 microM or 30 microM arsenite. There was no apparent loss of kDNA in the process. Most of the changes observed appear to involve a shift in either the dominance or the copy number of different minicircle subclasses. Surprisingly, the kDNAs of tunicamycin-resistant variants (T variants) were also found to undergo similar changes. Genetic changes previously described in both A and T variants are limited to their nuclei. Namely, different chromosomal regions are amplified to produce large DNA circles which are responsible for the drug-resistant phenotypes. Interestingly, other arsenite-resistant clones without such chromosomal DNA amplification (A' variants) had kDNA of the wild-type pattern. The profound changes of kDNA observed are unprecedented. We propose the term "transkinetoplastidy" for this phenomenon to distinguish it from dyskinetoplastidy or the loss of kDNA described previously in trypanosomatid protozoa. This phenomenon is discussed with respect to the possible mechanisms of its generation, regulation and relation to the drug-resistant phenotypes.

Conserved terminal sequences of rice ragged stunt virus genomic RNA

The 5'- and 3'-terminal nucleotide sequences of the dsRNA genome segments of rice ragged stunt virus (RRSV), a member of the plant Reoviridae, were determined and compared with those published for other viruses in this family. The 5'- and 3'-terminal regions of the RRSV plus strand RNA from all genome segments were found to have the same conserved hexanucleotide (5' GAUAAA---) and tetranucleotide (---GUGC 3') sequences, respectively. These conserved terminal sequences were different from those found in viruses in the Phytoreovirus and Fijivirus genera. This result confirms that, as already suggested, RRSV should be placed in a third genus.

Quantitative evaluation of optic disc pallor in pseudotumor cerebri patients

We quantified optic disc pallor in patients with pseudotumor cerebri with the Rodenstock Optic Nerve Head Analyzer before and after optic nerve sheath decompression. Mean frequency distribution of pallor peaked between the pallor values of 0.10 and 0.20 in four pseudotumor cerebri patients and between 0.50 and 0.60 in five normal subjects. The red dominant pallor reflectance in pseudotumor cerebri patients decreased significantly and shifted toward the reflectance of normal subjects gradually during the 9 weeks after successful optic nerve sheath decompression, coinciding with the ophthalmoscopic resolution of papilledema. The computerized pallor measurement with the Rodenstock Optic Nerve Head Analyzer allows an objective and quantitative assessment of papilledema in pseudotumor cerebri patients.

Investigation into allergic response in patients with chronic sinusitis

We attempted to investigate the role of nasal allergy in sinusitis to elucidate whether it results from an immediate-type allergic reaction of the sinus mucosa or from allergic edema-induced sinus ostial obstruction. Forty-two patients with chronic sinusitis were selected for allergen skin tests, measurements of serum total and specific IgE, and sinus tissue-specific IgE. The data were then correlated to examinations of nasal mucosal scrapings and histopathology of the sinus mucosa. We found that serum levels of total IgE and house dust mite-specific IgE antibodies were significantly higher in patients (n = 12) allergic to house dust than in the nonatopics (n = 30; p less than 0.0001). There was no difference in the sinus tissue-specific IgE antibody. Eosinophils and basophilic cells in epithelial scrapings from the inferior turbinates, assessed by Hansel staining, were high in 66.7% and 50% of the atopic patients, respectively, and 36.7% and 26.7% of the nonatopics, respectively. The rates were influenced by the existence of infection and nasal polyps. The increase in eosinophils, mast cells and plasma cells, assessed by histopathologic examination, were not prevalent in the sinus mucosa of atopic patients. It is concluded that nasal allergy may be a predisposing factor to sinusitis and that the pathologic change of the sinus mucosa is mainly secondary, due to sinus ostial obstruction.

Experimental blunt injury to the larynx

This article deals with the fracture line distribution and severity of laryngeal trauma. Laryngeal trauma was experimentally inflicted on 100 human laryngeal specimens with the impact of a 2.0-kg weight falling by gravity from a height of 100 cm. According to the previous pilot experiment and clinical experiences, the author classified the severity of fracture into four grades. The results showed no significant sex difference in the severity of fracture with reference to age distribution, especially severe injury in older age groups. The pattern of fracture lines of the laryngeal cartilage was observed and traced in four selected locations, including the thyroid notch, central zone of the thyroid cartilage, cricothyroid region, and cricoid. The distributions of fracture lines are illustrated. The experiment is described in detail.

Tellurium-induced alterations in 3-hydroxy-3-methylglutaryl-CoA reductase gene expression and enzyme activity: differential effects in sciatic nerve and liver suggest tissue-specific regulation of cholesterol synthesis

The demyelination of peripheral nerves that results from exposure of developing rats to tellurium is due to inhibition of squalene epoxidase, a step in cholesterol biosynthesis. In sciatic nerve, cholesterol synthesis is greatly depressed, whereas in liver, some compensatory mechanism maintains normal levels of cholesterol synthesis. This tissue specificity was further explored by examining, in various tissues, gene expression and enzyme activity of 3-hydroxy-3-methylglutaryl-CoA reductase, the rate-limiting enzyme in cholesterol biosynthesis. Exposure to tellurium resulted in pronounced increases in both message levels and enzyme activity in liver, the expected result consequent to up-regulation of this enzyme in response to decreasing levels of intracellular sterols. In contrast to liver, levels of mRNA and enzyme activity in sciatic nerve were both decreased during the tellurium-induced demyelinating period. The temporal pattern of changes in 3-hydroxy-3-methylglutaryl-CoA reductase message levels in sciatic nerve seen following exposure to tellurium was similar to the down-regulation seen for mRNA specific for PNS myelin proteins. Possible mechanisms for differential control of cholesterol biosynthesis in sciatic nerve and liver are discussed.

Crystallization and a preliminary X-ray crystallographic study of alpha-amylase from Bacillus licheniformis

alpha-Amylase from Bacillus licheniformis has been crystallized by the hanging-drop vapor diffusion method in the presence of calcium ions using ammonium sulfate as precipitant. The crystals are tetragonal, belonging to the space group P4(1)2(1)2 (or P4(3)2(1)2), with unit cell dimensions of a = 119.9 and c = 85.4 A. The asymmetric unit contains one molecule of alpha-amylase, with a crystal volume per protein mass (VM) of 2.78 A3/Da. The crystals diffract to better than 2.0 A Bragg spacing when exposed to synchrotron X-rays and they are reasonably stable in the X-ray beam. Thus the crystals are suitable for structure determination at high resolution by X-ray methods.

Reproductive performance following ectopic pregnancy

The reproductive performance subsequent to operative removal of ectopic pregnancy was examined in 132 women. They represent 44.6% of 296 women admitted for ectopic pregnancy between 1981 and 1989. The follow-up period ranged from 6 months to 9 years, averaging 3.6 years. During the follow-up period, 69 (52.3%) pregnancies occurred. Among them, 60 (87%) were intrauterine and 9 (13% of the pregnant women) were repeated ectopic pregnancies. Full-term delivery was obtained in 73.9% of the pregnant patients. Forty of the 132 patients received conservative surgery and 92 patients received radical surgery for ectopic pregnancy. The operation method had no influence on subsequent fertility in women with an intact contralateral tube, who had significantly higher pregnancy (p less than 0.005) rate (3.8%) than women with an affected contralateral tube (39.5%, 47% and 41%, respectively). Compared with parous women (13.3%), the risk of repeated ectopic pregnancy was similar to nulliparous women (12.5%), but the nulliparous women had a slightly lower conception rate (40%) than parous women (54.8%). Unruptured ectopic pregnancies comprised 41.6% of our cases. There was no significant difference in fertility rate between ruptured and unruptured ectopic pregnancies in our study.

Primary demyelination induced by exposure to tellurium alters mRNA levels for nerve growth factor receptor, SCIP, 2',3'-cyclic nucleotide 3'-phosphodiesterase, and myelin proteolipid protein in rat sciatic nerve

Weanling rats fed a diet containing tellurium develop a peripheral neuropathy characterized by a highly synchronous primary demyelination; this demyelination is followed closely by a period of rapid remyelination. The demyelination is related to the inhibition of squalene epoxidase activity, which results in a block in cholesterol synthesis. Expression of mRNA for the major structural proteins of PNS myelin, myelin basic protein and P0, is coordinately down-regulated during the demyelinating phase and then up-regulated during the remyelinating phase (Toews et al., J. Neurosci. Res., 26 (1990) 501-507). We now report tellurium-induced alterations in gene expression for several proteins which are not major structural components of myelin in the peripheral nervous system. Expression of mRNA for nerve growth factor receptor in sciatic nerve was very low in control animals, but was markedly up-regulated after 3-5 days of exposure to tellurium, a time corresponding to the beginning of demyelination. Levels remained elevated during the subsequent period of remyelination. Expression of mRNA for SCIP (a presumptive transcription factor) was also up-regulated in sciatic nerve following tellurium exposure, with a time course similar to that for nerve growth factor receptor. When examined as a fraction of total RNA, steady-state mRNA levels for 2',3'-cyclic nucleotide 3'-phosphodiesterase and the myelin proteolipid protein were decreased during the demyelinating phase; however, this decrease could be largely accounted for by increased levels of total RNA. When analyzed on a 'per nerve' basis, steady-state mRNA levels for these two proteins were actually increased about 2-fold by 9 days after beginning tellurium exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Salmonella enterica subspecies diarizonae bacteremia in an infant with enteritis--a case report

The septicemia caused by the Arizona group organism is rare and usually observed in adults with underlying diseases. In Korea, Salmonella infection is common, but a report of Arizona infection is unknown. We isolated S. entercia subsp. diarizonae from blood of a 6-month-old infant. The serovar was determined as 28:z10:-, a rare one in America. The isolate was susceptible to ampicillin, chloramphenicol, cotrimoxazole and others. The patient rapidly recovered with ampicillin and gentamicin therapy. Clinical laboratories should consider that the infection exists in Korea and should attempt to isolate and identify Arizona organism in certain patients.

Biodynamic simulations of the effect of a neck-mounted air bag on the head/neck response during high G acceleration

New helmet-mounted devices (such as night-vision goggles, laser eye protection, etc.) have created new safety hazards for pilots during ejection or high G maneuvering. In order to prevent the resulting head/neck injuries, this study extends the air-bag protection system developed for ground vehicles to a neck mounted system for aircrew personnel. Results, carried out by computer biodynamic simulations using the Articulated Total Body Model (ATB), showed that: 1) helmet weight had little effect on head/neck torque, contact force and flexion angle; 2) initial head/neck position and center of gravity offsets of the helmet-mounted devices had significant effects on head-neck torques, contact forces, and neck flexion angles; and 3) the neck mounted air bag significantly reduced neck torques, contact forces, and neck flexion angles. We conclude that the neck-mounted air bag system could significantly reduce the severity of head/neck injuries to pilots during ejection or high G maneuvering.

Additive effect of 1% apraclonidine hydrochloride to nonselective beta-blockers

The short-term additive effect and side effects of adding 1% apraclonidine hydrochloride to nonselective beta-blockers were investigated in 21 patients with ocular hypertension or early primary open-angle glaucoma. After a unilateral single dose application of topical 1% apraclonidine hydrochloride, intraocular pressure (IOP), heart rate, and interpalpebral distance were measured. The mean IOP of treated eyes showed a decline from a baseline of 20.0 +/- 3.0 mmHg to 18.1 +/- 3.2 mmHg at 1 hour (P less than 0.005), 16.5 +/- 2.6 mmHg at 2 hours (P less than 0.001), 15.2 +/- 2.5 mmHg at 3 hours (P less than 0.001), 18.5 +/- 3.0 mmHg at 12 hours (P = 0.02), and 19.2 +/- 2.9 mmHg at 24 hours (P = 0.2). No statistically significant change in the heart rate was seen. The interpalpebral distance of the treated eyes showed a significant increase (P less than 0.05) at all time intervals except 24 hours (P = 0.17). The authors conclude that 1% apraclonidine hydrochloride provides an additive pressure-lowering effect to nonselective beta-blockers for at least 12 hours after a single application, and shows promise as a useful adjunctive agent for short-term use in glaucoma therapy.

[Antenatal screening of maternal alpha-fetoprotein with dried-blood spot samples on filter paper]

Abnormal levels of maternal serum alphafetoprotein (AFP) have been used as a good biochemical marker for the screening of neural tube defects (NTD) and Down syndrome. From January 1988 to June 1989, we conducted a community-based maternal AFP screening program in Nan-Tou County, which is located in the middle of Taiwan. A total of 3,776 pregnant women, which accounted for about 42% of the total number of women pregnant during that period of time in Nan-Tou county, were screened using the filter paper blood collecting technique. Of those screened, 5.1% of them were found to be borderline positive for NTD (2.0 less than MoM less than 2.5). The screening positive rates for NTD (MoM greater than 2.5) and Down syndrome (Down's risk greater than 1/100) were 3.7% and 1.7%, respectively. Except for those lost to follow-up, 3 (2.1%) of the borderline cases were confirmed to have serious pregnancy complications (porencephaly, fetal demise, and imminent miscarriage). Eleven (10.8%) of the abnormal pregnancies, which included 1 case of possible hydrocephalus, 2 cases of anencephalus, and 1 case of triploid, were found in the NTD positive group. Six (18.7%) anomalies (1 Down syndrome, 1 hydatidiform mole, and 4 miscarriages) were detected in the increased Down's risk group. Totally, 20 adverse pregnancies, i.e. 0.5% (20/3,776) of the screened women, were confirmed in this screening program. No false-positive cases were reported, or were found among the 1,777 post-delivery questionnaires completed.(ABSTRACT TRUNCATED AT 250 WORDS)

Lactobacillus casei subspecies casei endocarditis--a case report

Lactobacillus sp., generally considered to be a harmless indigenous bacteria of the mucous membrane, occasionally causes serious infections. Lactobacillus endocarditis is a very rare disease, and no case has been reported in Korea. Gram-positive bacilli were isolated from blood cultures of a 41-year-old man with clinically suspected subacute bacterial endocarditis. The patient had a dental procedure 3 months prior to the infection. The isolate was identified as L. casei subsp. casei based on the cultural characteristics and gas liquid chromatography of metabolic products. The patient was treated with ampicillin and improved. When Lactobacillus is isolated from the blood of an endocarditis patient, the significance should be seriously considered.

Parallelization of the EM algorithm for 3-D PET image reconstruction

The EM algorithm for PET image reconstruction has two major drawbacks that have impeded the routine use of the EM algorithm: the long computation time due to slow convergence and a large memory required for the image, projection, and probability matrix. An attempt is made to solve these two problems by parallelizing the EM algorithm on multiprocessor systems. An efficient data and task partitioning scheme, called partition-by-box, based on the message passing model is proposed. The partition-by-box scheme and its modified version have been implemented on a message passing system, Intel iPSC/2, and a shared memory system, BBN Butterfly GP1000. The implementation results show that, for the partition-by-box scheme, a message passing system of complete binary tree interconnection with fixed connectivity of three at each node can have similar performance to that with the hypercube topology, which has a connectivity of log(2) N for N PEs. It is shown that the EM algorithm can be efficiently parallelized using the (modified) partition-by-box scheme with the message passing model.

Influence of extract of Rosa rugosa roots on lipid levels in serum and liver of rats

The effects of the methanol extract of Rosa rugosa roots on serum and liver lipids were studied in rats. The rats were fed the purified diets with or without the methanol extract at the 1% level for 4 weeks. The concentrations of serum and liver total cholesterol were not significantly affected by the feeding of extract. Feeding of the extract, on the other hand, reduced the liver triacylglycerol content without influencing the serum triacylglycerol level. The effects of the extract on lipids profiles were diminished markedly by dietary cholesterol. The results suggest an existence of component in the extract which may ameliorate the accumulation of triacylglycerol in rat liver.

Pathodynamics of intoxication in rats and mice by enterotoxin of Clostridium perfringens type A

The pathodynamics of lethal intoxication in rats and mice by i.v. administration of enterotoxin of Clostridium perfringens type A was studied using whole animals and isolated organs. A lethal i.v. dose (50 micrograms/kg) of enterotoxin killed anesthetized rats and mice within 4-15 min. Rapid changes of ECG pattern suggestive of hyperpotassemia, rapid fall of blood pressure and transient hyperpnea followed by respiratory depression were observed. Analysis of plasma levels of cations revealed hyperpotassemia in both animal species. On the other hand, enterotoxin (up to 100 micrograms) showed little direct cardiotoxicity on the isolated heart. ECG changes produced by i.v. injection of KCl (0.5 ml of 50 mM) mimicked the ECG changes observed in the intoxicated rats injected with a lethal dose of enterotoxin. Perfusion of rat isolated organs showed that potassium concentration in the eluent from the liver (but not lungs or lower extremities) increased markedly within 1-2 min after the administration of enterotoxin. The amount of potassium liberated from a rat liver was about 133 mumoles, which is sufficient to increase the plasma level of potassium to more than 10 mM. In addition to potassium, cytoplasmic enzymes, such as glutamate oxalacetate transaminase, glutamate pyruvate transaminase and lactate dehydrogenase, were also liberated from the intoxicated liver, indicating that potassium was liberated from hepatocytes by the change in membrane permeability produced by enterotoxin. It is concluded that hyperpotassemia elicited by the cytotoxic action of enterotoxin on hepatocytes caused cardiac failure leading to the death of the intoxicated animals.

A simple procedure for maximum yield of high-quality plasmid DNA

We have established a simple procedure for the rapid isolation of high-quality plasmid DNA suitable for various molecular techniques and provided a step-by-step protocol. The DNA samples isolated by this procedure have been used successfully for double-stranded DNA sequencing, restriction enzyme mapping, subcloning, in vitro mutagenesis, generation of deletion clones and so on. The procedure is highly reproducible, and superior quality DNA can be obtained without the use of phenol, chloroform or other organic solvents.

Limb-salvage operations in primary malignant tumors of the bone--interim report

Between June 1985 and March 1990, 25 patients with primary malignant bone tumors, including 15 cases of osteogenic sarcoma, two cases of periosteal osteogenic sarcoma, six cases of chondrosarcoma, and two cases of malignant fibrous histiocytoma, were treated with limb-salvage procedures. Fourteen patients underwent limb salvage operations with tumor prosthesis arthroplasty, 6 with resection-arthrodesis, 4 with wide resection, and 1 with autoclaved autograft. Pre- and/or post-operative chemotherapy with or without radiotherapy was combined with these limb salvage operations. The average follow-up period was 25.2 months (6 to 52 months) since diagnosis. The estimated 3.5-year survival rate of the total 25 patients was 39.5% based on the Kaplan-Meier survival plot. In the 15 cases of osteogenic sarcoma, the estimated Kaplan-Meier 34-month survival rate was 46.2%. Seventeen patients who were followed up for more than 1 year were grouped by functional grading: 11 (65%) were excellent; 3 (18%) good; 2 fair (12%); and 1 poor. Complications occurred in 4 patients, 1 had a local recurrence, 2 had superficial wound infections, and 1 a loosening of the femoral stem. Metastases were shown in 15 case, and the most common location was the lung.