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PubMed2000

Nuclease-hypersensitive chromatin formed by a CpG island in human DNA cloned as an artificial chromosome in yeast.

CpG islands are mostly unmethylated GC-, and CpG-rich chromosomal segments overlapping promoter sequences in all housekeeping and many tissue-specific genes in vertebrates. Typically, these islands show an open chromatin structure, low in histone H1 and rich in acetylated histones. We have previously found that the island-like CGCG-rich sites in human DNA are hypersensitive to DNase I upon cloning in Saccharomyces cerevisiae. Here we studied, with a higher resolution, the chromatin formed in yeast by one such site, the CpG island accompanying the human glucose-6-phosphate dehydrogenase gene. We have found two strong hypersensitive sites and several positioned nucleosomes flanking the island despite the absence in yeast of such chromatin fiber-shaping factors as histone H1, methyltransferase, and the tissue-specific transcription factors. This finding, together with similar observations from our laboratories and others supports the idea that variations in GC and/or CpG content substantially contribute to the DNA sequence features modulating the structure of the chromatin. The composition-dependent fluctuations in the accessibility of DNA in the chromatin may constitute an evolutionary advantage and may explain the surprising compositional selection that acts in both the coding and non-coding segments of some genes during mammalian evolution.

Chromatin↗
PubMed2005

Human immunodeficiency virus type 1 variants isolated from single plasma samples display a wide spectrum of neutralization sensitivity.

Individuals infected with human immunodeficiency virus type 1 (HIV-1) harbor a mixture of viral variants with different sequences and in some instances with different phenotypic properties. Major and rapid fluctuations in the proportion of viral variants coexisting in an infected individual can be observed under strong pharmacological and immune selective pressure. Because of the short half-life of HIV-infected cells and of HIV virions in the blood, plasma virus populations are highly relevant to HIV evolution in the face of these selective pressures. Here we analyzed the sensitivity to antibody-mediated neutralization of viral variants coexisting in the plasma virus populations of two infected patients. For each patient, several replication-competent viral clones were constructed that carry primary envelope gene sequences obtained from a single plasma sample. Viral clones differed in their tropism and replicative capacity and in the number and positions of glycosylation sites in the envelope glycoproteins. Viruses were tested against heterologous and autologous sera obtained at different time points. Interestingly, we found that viral variants coexisting in each plasma sample were highly heterogeneous in terms of sensitivity to neutralization. The order of sensitivity depended on the serum used and was not associated with virus tropism. The neutralization potency of sera increased with the duration of the infection for both autologous and heterologous neutralization.

Amino Acid Sequence↗
PubMed1999

Perspectives in the treatment of Parkinson's disease: COMT inhibitors open up new treatment strategies.

Catechol O-methyltransferase (COMT) inhibition has been proposed as a means to increase levodopa bioavailability in patients with Parkinson's disease, which may be useful in reducing the total dose of levodopa, diminishing its frequency of administration and, more importantly, improving fluctuations in the response to each individual dose of levodopa, which usually develop after chronic treatment. Entacapone is a potent, selective peripheral catechol O-methyltransferase inhibitor which effectively inhibits the O-methylation of levodopa, thus increasing its central bioavailability and potentiating its behavioral effects. In clinical trials in patients with Parkinson's disease, entacapone has prolonged and improved the therapeutic effect of levodopa combined with a dopa decarboxylase inhibitor. The new drug has increased the "on" time duration, decreased the "off" time duration and has reduced the total dose requirements of levodopa. Entacapone has shown optimal tolerability at the currently recommended doses, with the added benefit of a lower required dose of levodopa. This, in turn, improves the tolerability of levodopa and thus the overall tolerability of the treatment of advanced Parkinson's disease.

Journal Article↗
PubMed2000

[A case of Ondine curse associated with a medullary tumor].

A 49-year-old woman with 6 months history of body weight loss, muscle weakness, and dysarthria, was found with respiratory arrest and resuscitated in the morning of January 1999. An MRI brain scan revealed diffuse swelling and T2/FLAIR high signal intensity with mild Gadolinium enhancement in the lower pons and medulla oblongata. Although the histological diagnosis could not be obtained, glioma (astrocytoma) was suspected. In the morning of July 3rd she presented sweating and cyanosis. Her arterial oxygen saturation was 18%. When we asked her to breathe more, she kept breathing and oxygen saturation was normalized. However, she could not breathe at all when she fell asleep without stimulation. She was kept under respiratory support for 2 months. Her symptoms improved with fluctuating course after 70 Gy of radiation therapy. Ondine curse is one type of sleep apnea syndrome, defined as the selective disturbance of autonomous breathing. Surgical operation and stroke are the reported causes of this syndrome. Brainstem tumor is relatively common cause for children's Ondine curse. On the other hand, it rarely causes adult's Ondine curse as a main symptom.

Astrocytoma↗
PubMed1975

[Value of alkane-produced protein and three animal meals for growth and body nitrogen of meal worms (Tenebrio molitor L.)].

Different types of chemical and biological procedures for screening protein quality of many foods are available. It is recognized however that such assays cannot be part of a routine screening technic. For good technologists and plant breeders in search of novelties, the main problems arise from the small size of samples available and the need to evaluate a large number of materials in a short period of time. The development of more accurate, economical and/or faster bioassay methods would be useful for solving some of the general and applied nutrition problems. The possibility of using larvae of the yellow mealworm (Tenebrio molitor L.) as a bioassay test organism for nutritional evaluation of proteins has been suggested (8) and previous investigations (9, 10, 11, 12,13, etc.) indicated that these larvae can be used in such studies because of a short, rapid growth period and a sensitivity to slight changes in protein quality and quantity. The present investigation was designed to asses the nutritional quality of artificial diets containing various levels of BP-protein (pure n-alkanes grown yeast or yeast G) when fed to larvae of T. molitor. The results were compared with those of Difco vitamin-free casein, fish and meat meals studied in the same manner. The chemical compositions of these proteins sources was also reported. Defatted meals of the samples were used to prepare diets containing from 0,6 to 20 p. 100 of dietary protein. The basic protein free diet used contained: dextrose: 97 p. 100, McCollum's salt mixture: 2 p. 100, cholesterol: 1 p. 100 and a solution of B-vitamins and zinc chloride: 0,1 ml/g. The dextrose portion of the diets is adjusted as the protein concentration fluctuates. Larvae of T. molitor, Gembloux strain, race F, ranging in weight from 9,60 to 12,00 mg were selected from stock cultures, rearing in the ground wheat-Brever's yeast medium. They were starved for 48 hr. and were weighed again before being placed on the test diets for 4 weeks. Groups of thirty larvae having an average initial weight of approximately 10 mg were reared individually in vials at 27 degrees C and 70 p. 100 relative humidity with 1,5 g of diet each. At the end of the experimental period,the larvae were weighed to the nearest 0,1 mg and the gains in fresh weight were recorded. Then, all the larvae from the same diet, previously killed with chloroform were used from nitrogen determinations. Data on gains in weight and body nitrogen of larvae were analyzed, using analysis of variance and NEWMAN and KEUL's multiple range test. The results suggest that the protein levels allowing maximuum growth and body nitrogen vary from 9 to 12 p. 100 and these levels were suitable for the comparisons. Based on the criterion of larval weight, the nutritional quality of the protein sources was : BP-protein greater than casein = fish meal greater than meat meal (P less than 0,01)...

Amino Acids↗
PubMed2003

Effect of insecticide-treated bednets for malaria control in Southeast Anatolia-Turkey.

Deltamethrin is one of the most effective insecticides for vector control, already widely used for bednet impregnation to control malaria. To evaluate the efficacy of deltamethrin-impregnated bednets in malaria control and in reducing the biting nuisance caused by Anopheles sacharovi, field trials were carried out in an endemic area of malaria in the surrounding rural settlements of Sanliurfa City, SE Anatolia, Turkey. Preliminary studies commenced in August 1999 with pre-intervention house-to-house surveys to identify villages outside of Sanliurfa City with high malaria incidence, to collect socio-economic, epidemiological and entomological data, and to determine physical properties of the study areas. An intervention field trial promoting the use of K-OTAB (deltamethrin-tablet formulation) impregnated bednets by local inhabitants of four villages was performed between July 2000 and July 2001. Its aim was to examine the monthly and annual efficacy of such bednets in controlling malaria and to compare the effect of impregnated bednets (IB) with non-impregnated bednets (NIB). The experimental design consisted of four villages. Gedik was selected as the intervention area using IBs, Orgulu served as the control area, and in Persiverek and Sandi NIBs were implemented. All 1,406 inhabitants of the 146 households were recruited for the study. Results showed significant (P < 0.05) reduction in malaria incidence in Gedik from 8.29% in the pre-treatment year to 1.57% in the post-treatment year. In contrast, malaria incidence slightly increased in Orgulu from 6.55% to 7.58%. Similar results were obtained from the other two villages where NIBs were used; malaria incidence rates increased from 2.16% to 6.77% (Persiverek) and from 1.9% to 9.8% (Sandi). Entomological surveys, employing different techniques, were carried out randomly at selected collection sites within the intervention and control settlements every month from June 2000 to June 2001 to determine the fluctuation of seasonal population sizes and compare the monthly density of malaria vectors between intervention and control areas.

Animals↗
PubMed2005

A 2 year followup study of enhanced magnetic resonance imaging and clinical examination of the temporomandibular joint in children with juvenile idiopathic arthritis.

OBJECTIVE: Involvement of the temporomandibular joint (TMJ) in patients with juvenile idiopathic arthritis (JIA) can cause severe craniofacial growth disturbances if not treated in the initial stage. Magnetic resonance imaging (MRI) is an efficient method for detecting early inflammatory changes of the TMJ. We investigated correlation between findings from the clinical examination with MRI of the TMJ, and describe development of the MR image over time. METHODS: Fifteen children with newly diagnosed JIA (mean age 12.0 yrs) were examined clinically and with MRI enhanced with Gd-DTPA 4 times at 6-8 month intervals. Clinical and MRI findings were scored. MRI variables included T1 weighted images before and after administration of Gd-DTPA with and without fat suppression. RESULTS: A total of 115 joints were examined during the 2 year period: 93% showed enhancement, 71% condylar erosions, 26% pannus, and 23% joint fluid accumulation of the TMJ. In all except one child, one or both TMJ showed enhancement of the synovial membrane during the examination period. Symptoms were rare. All patients showing mild to severe findings by clinical examination also had pathological signs on the enhanced MRI, but not all patients without clinical findings had a normal MRI. CONCLUSION: TMJ involvement in patients with JIA is very common, and MRI findings such as synovial enhancement, pannus, and joint fluid fluctuate over time. The clinical examination may be used as a filter, where children showing no clinical signs could be selected for enhanced MRI.

Adolescent↗
PubMed2006

[Anesthetic management of laparoscopic adrenalectomy for pheochromocytoma].

OBJECTIVE: To investigate the anesthetic management features of laparoscopic adrenalectomy for pheochromocytoma. METHODS: Twelve patients scheduled for laparoscopic adrenalectomy for pheochromocytoma under general anesthesia were allocated into group 1, while another 12 patients who received transabdominal adrenalectomy for pheochromocytoma under general anesthesia were selected as group 2. The hemodynamic changes and the postoperative recovery profiles between the two groups were compared. RESULTS: Hemodynamic fluctuation occurred during carbon dioxide insufflation and tumor manipulation in group 1. However, there were no differences between the two groups. Duration of post operative recovery and hospital stay as well as requirement of analgesics in group 1 were significantly lower than those in group 2 (P < 0.05). CONCLUSION: Hemodynamic fluctuation still exists during laparoscopic adrenalectomy for pheochromacytoma. However, patients undergoing such surgical procedure recover faster as compared with open surgery.

Adrenal Gland Neoplasms↗
PubMed1997

Activation of the alternative pathway of complement by a phosphorothioate oligonucleotide: potential mechanism of action.

Intravenous infusion of high doses of phosphorothioate oligonucleotides in monkeys has been associated with transient alterations in hematologic and hemodynamic parameters, which appear to be secondary to complement activation. ISIS 2302, a phosphorothioate oligonucleotide specific for human intracellular adhesion molecule-1, was used to further characterize complement activation in monkeys. Complement activation occurred selectively through the alternative pathway resulting in increased plasma concentrations of the complement split products Bb, C3a and C5a. Marked fluctuations in circulating neutrophil counts and reductions in cardiac output were closely associated with peak production of anaphylatoxins C3a and C5a. Changing both dose and infusion duration revealed that complement activation is related to plasma levels of oligonucleotide, and that there is a minimum threshold concentration of approximately 50 micrograms/ml of ISIS 2302 that is required to activate complement. Dose regimens in which plasma concentrations do not exceed this threshold do not result in complement activation. Further investigation reveals that plasma concentrations of a key regulatory component of the alternative pathway, Factor H, were also decreased after administration of ISIS 2302. Decreases in Factor H levels are suggestive of a possible mechanism of complement activation. Direct interaction between ISIS 2302 and Factor H was demonstrated in a competition assay, where increasing concentrations of ISIS 2302 eluted Factor H from a heparin-sepharose column. These data demonstrate a clear correlation between plasma oligonucleotide concentrations and complement activation. Interactions between ISIS 2302 and Factor H may lead to activation of the alternative complement pathway.

Animals↗
PubMed1995

Psychiatric morbidity: a multilevel approach to regional variations in the UK.

STUDY OBJECTIVE: To establish whether regional variations in psychiatric morbidity in Britain constitute a distinctive geography of mental health arising from factors that are context-specific at area level or whether these variations are an artifact generated by sampling fluctuations and differing population compositions in areas. DESIGN: Multilevel modelling techniques were applied to data from the 1984-85 health and lifestyle survey. The outcome was the prevalence of psychiatric morbidity as recorded by the application of the general health questionnaire in this survey. SETTING: The analysis was undertaken simultaneously at the individual level, electoral ward level, and regional level for England, Wales, and Scotland. PARTICIPANTS: A total of 6572 adults were selected from the electoral register. MAIN RESULTS: Regional variations were detected in crude aggregate general health questionnaire scores but these were found to be the result of sampling fluctuations and varying regional population compositions rather than higher level contextual effects. There was certainly no evidence of a clear north-south distinction in psychiatric morbidity as was suggested by earlier work. In addition, the local neighbourhood did not seem to have any importance beyond the type of people who lived there. A number of individual characteristics was shown to be associated with mental wellbeing but a large degree of individual variation remained unexplained. CONCLUSIONS: In terms of low level psychiatric disturbance it seems that the characteristics of individuals have greater importance than the characteristics of areas, although the latter may still operate as important mediating factors. Multilevel modelling represents a robust statistical method of examining area variations in health outcomes and further work needs to be conducted, particularly on more serious psychiatric conditions.

Adult↗
PubMed2004

Endothelin receptor in virus-like particles: ligand binding observed by fluorescence fluctuation spectroscopy.

The functional analysis of transmembrane receptor proteins is frequently hampered by the difficulty to produce sufficiently homogeneous receptor preparations that preserve the physiological biomembrane integration of the receptor protein. To improve the receptor protein density in the lipid bilayer and to maintain the physiological lipid-protein environment, a novel method has been established that enables the selective integration of transmembrane receptors into a virus-like particle (VLiP). Here we have studied the binding of tetramethylrhodamine-labeled endothelin-1 (TMR-ET-1) to VLiP-integrated endothelin A receptor (ET(A)R) by fluorescence fluctuation spectroscopy. The concentration of TMR-ET-1 was determined by fluorescence correlation spectroscopy (FCS). These measurements also confirmed that the free ligand is monomeric in solution in our experiments. Fluorescence intensity distribution analysis (FIDA) was used to quantify the fraction of ligands bound to ET(A)Rs in the VLiPs. For the interaction between ET-1 and VLiP-integrated ET(A)Rs, K(D) values of 0.5 nM and 0.3 nM were determined from ligand and receptor titration experiments, respectively. For comparison, a FIDA analysis was also carried out with ET(A)Rs in membrane fragments derived from an ET(A)R-overexpressing mammalian cell line, which yielded a similar K(D) of 0.2 nM. In addition, we examined the binding competition of a set of reference compounds to VLiP-ET(A)Rs in the presence of ET-1 and obtained K(i) values similar to those reported in the literature. Our results demonstrate that integration into VLiPs does not change the binding properties of the ET(A)Rs. FIDA analysis of VLiP-integrated receptors shows great promise for highly miniaturized and fast compound testing in the pharmaceutical industry.

Cell Line↗
PubMed2006

Plastic neuronal changes in GABA(A) receptor gene expression induced by progesterone metabolites: in vitro molecular and functional studies.

Expression of specific gamma-aminobutyric acid type A (GABA(A)) receptor subunit genes in neurons is affected by endogenous modulators of receptor function such as neuroactive steroids. Neuroactive steroids such as the progesterone metabolite allopregnanolone might thus exert differential effects on GABA(A) receptor plasticity in neurons, likely accounting for some of the physiological actions of these compounds. Here we summarise experimental data obtained in vitro that show how fluctuations in the concentration of progesterone regulate both the expression and function of GABA(A) receptors. The data described in this manuscript are in agreement with the notion that fluctuations in the concentrations of progesterone and its metabolite allopregnanolone play a major role in the temporal pattern of expression of various subunits of the GABA(A) receptor. Thus, rapid and long-lasting increases or decreases in the concentrations of these steroid derivatives observed in physiological and patho-physiological conditions, or induced by pharmacological treatments, might elicit selective changes in GABA(A) receptor gene expression and function in specific neuronal populations. Given both the importance of GABA(A) receptors in the regulation of neuronal excitability and the large fluctuations in the plasma and brain concentrations of neuroactive steroids associated with physiological conditions and the response to environmental stimuli, these compounds are likely among the most relevant endogenous modulators that could affect emotional and affective behaviors.

Animals↗
PubMed1993

Phorbol 12,13-dibutyrate produces negative inotropism and selective antagonism of responses to adrenoceptor agonists in rat atria.

Rat atria loaded in vitro with the dye INDO-1 produced fluorescence signals indicative of changes in cytoplasmic calcium ion concentration ([Ca2+]c). Such atria showed systolic/diastolic fluctuations indicative of a systolic rise and a diastolic fall in both tension and [Ca2+]c. Positively inotropic responses of the atria to isoprenaline, phenylephrine, ouabain or 4-aminopyridine were associated with fluorescence changes indicative of increased systolic increments in [Ca2+]c. Treatment of atria with phorbol dibutyrate, on the other hand, produced negative inotropism and fluorescence changes indicative of declining systolic increments in [Ca2+]c. Pretreating atria with phorbol dibutyrate diminished both the inotropic and fluorescence responses to subsequent treatment with phenylephrine or isoprenaline, although responses to ouabain or 4-aminopyridine were unchanged. Exposure of atria to a selective inhibitor of protein kinase C mitigated the effects of pretreatment with phorbol dibutyrate, but failed to modify responses to phenylephrine or isoprenaline that were produced in the absence of phorbol dibutyrate.

4-Aminopyridine↗
PubMed1983

Studies on the epidemiology of schistosomiasis in Liberia: the prevalence and intensity of schistosomal infections in Bong County and the bionomics of the snail intermediate hosts.

Urine samples from 3548 individuals residing in six of the eight districts which comprise Bong County, Liberia, the project area of the Bong County Agricultural Development Project (BCADP), and fecal specimens from 3408 of these individuals were examined for schistosome ova. A total of 164 water sites, including rice paddies, were surveyed for schistosome vector snails and monthly changes in snail population density and infection rate were determined in selected water sites. Bulinus globosus was more widely distributed than Biomphalaria pfeifferi but the latter species showed a higher infection prevalence (12.3%) than the former one (10.3%). Snail population density and infection rate fluctuated with season, being higher in the dry season and lower during periods of heavy rainfall. Dessication and/or heat stress may have contributed to the contraction of snail population size at the end of the dry season. More water sites contained infected snails during December through February than at any other time of the year. In selected water sites examined at monthly intervals, mean snail density was higher in rice paddies than in other water contact sites but the latter showed a higher prevalence of infected snails than the former. The overall prevalence of Schistosoma mansoni (24.8%) was significantly higher than that of S. haematobium (22.7%) but the difference in prevalence rates of two species in school children was not statistically significant. The intensity of S. haematobium infection (13.2 means G) was significantly higher than that of S. mansoni (6.3 means G). Mixed infections in school children did not have a significant effect on egg output. The prevalence and intensity of S. haematobium showed a dramatic decline between the age groups 0-15 and 20-50 + years old; the differences between these age groups in S. mansoni infection were unremarkable. In Zota, Jorquelle and Kokoya Districts, prevalence rates of S. haematobium were higher than those of S. mansoni; the reverse was observed in Suakoko and Panta-Kpai Districts but relative prevalence rates varied according to specific locality in each district. A south to north stratification of schistosomal infection prevalence was observed similar to the west to east gradient reported by Saladin et al. (1980). New rice paddies developed during the three year operational period of the BCADP contained little or no vector snails and schistosomal infections in farm families of these paddies reflected the characteristic of the disease in corresponding localities.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1983

Ascertainment of the effect of differential growth rates of mutants on observed mutant frequencies in X-irradiated mammalian cells. An indication for the occurrence of X-ray-induced untargeted mutagenesis.

As it is not known to what extent differential growth rates of induced mutants lead to over- and under-representation of mutants in treated populations and thereby affect the determination of mutant frequencies, the mutation induction in X-irradiated L5178Y mouse lymphoma cells was determined via two methods. The first method involves the standard protocol which may suffer from the effect of differential growth rates, while the second method is based upon the fluctuation test in which the differential growth rates can be actually measured. It appeared that the standard protocol led to a mutant frequency that was similar to the mutant frequency determined in the fluctuation test. Therefore, the standard protocol appears to lead to only a minor under-estimation if any. Substantial heterogeneity in growth rates of induced mutants was observed, but the mutants with a selective advantage appear largely to compensate for the mutants that are lost because of selective disadvantage. It was calculated that the chance for isolating the same mutant twice from a treated population had been increased 2.2-fold because of the observed differential growth rates. Therefore, our data indicate that the standard protocol does not lead to serious errors in the determination of mutant frequencies and in the sampling of mutants. The fluctuation tests were also used to determine the spontaneous mutation frequency per cell per generation. The mutation rate appeared more than 10-fold enhanced in X-irradiated cells which may be attributed to the induction of a process of untargeted mutagenesis in mammalian cells.

Animals↗
PubMed1987

Selection and adaptation for rapid growth in culture of cells from delayed sarcomas in nude mice.

More than 1000 cells of a spontaneously transformed line of BALB/3T3 cells are required to initiate tumors in half the nude mice inoculated s.c., although the cells clone with an efficiency approaching 100% in culture. The cells of two tumors with prolonged latent periods, initiated by 2 X 10(4) and 5 X 10(3) cells, were chosen for detailed clonal analysis in culture. The cells from the tumors grew very poorly in culture in the first passages, but with increasing speed and efficiency in later passages. Cells derived directly from the two tumors cloned in agar with an efficiency of 0.01 and 0.002%. The growth rates on plastic of the rare successful clones derived from agar were generally low but extremely varied. Some clones lost the capacity for multiplication in a few passages, while others persisted but fluctuated unpredictably in growth rate in the early passages. The graded increase in growth rate of the uncloned tumor cell populations was probably the result of selection of the more rapidly growing clones. One of the slower-growing clones was subcloned. About half of the subclones grew at a slower rate than the parental clone. These, however, increased progressively in growth rate over six successive weekly passages, suggesting the occurrence of a gradual physiological adaptation. We conclude that selection of fast-growing clones contributes a major part of the gradually improving growth of tumor cell populations in culture, but that a physiological adaptation extending over many cell generations makes a significant contribution. The mechanism in either case is unknown, and indeed there may not be a unique mechanism in the scientifically rigorous sense.

Animals↗
PubMed1979

[Seasonal Fluctuation Of Ascaris Reinfection Incidences In A Rural Korean Population]

This study was undertaken to estimate the reinfection incidence of Ascaris lumbricoides after biannual blanket mass chemotherapy and to figure out the characteristic seasonal fluctuation pattern in a Korean rural village. A total of 612 residents from 4 Ri's of Hwasung Gun, Kyunggi Do, Korea was selected and divided into 6 groups according to hamlets, each of which consisted of about 100 inhabitants. Each group received blanket biannual mass chemotherapy with 10 mg/kg of pyrantel pamoate respectively in each month, during the period from April 1977 to September 1978(Group A-April and October 1977 and April 1978, Group B-May and November 1977 and May l978, and so on). 1. Beforehand Ascaris infection status was evaluated by examining eggs and worms expelled exactly after the first mass chemotherapy checked during the first 6 months and the reinfection incidences were estimated in follow-up examinations during next l2 months by the above two kinds of methods and by detection of young Ascaris positive cases. Young Ascaris was defined as worm shorter than l3 cm and lighter than 500 mg and considered to have introduced to human host during the period from the previous 2 months to 2 weeks. The results were summarized as follows: 1.Beforehand infection rate with Ascaris were 42.3% (34.4~50.6% by group) by egg detection and 46.2% (36.2~51.9% by group) by worm detection methods in average. Number of worms per infected case was 2.7 (1.5~4.2 by group) in average. 2. Reinfection rates estimated by egg detection ranged from 8.0 to 3l.5% (l6.9% in average) in the first follow-up period and from 14.0 to 20.0% (l7.5% in average) in the second follow-up. Seasonal fluctuation was found marked and there were roughly two peaks, of which the larger appeared from February to March and the smaller from August to September. 3. Reinfection rates by worm detection method ranged from 20.6 to 34.9%(25.7% in average) and from 14.3 to 21.9% (19.6% in average) in respective follow-up examinations. Seasonal fluctuation was also observed and the peak incidence appeared one month earlier than those made by egg positive conversion. Number of worms per infected case decreased to 1.6 in average in both follow-up. 4. Young Ascaris detection rates ranged from 6.0 to 12.9% (9.4% in average) and from 2.3 to 5.8% (3.8% in average) in respective follow-up. Seasonal fluctuation was also observed. From January to February, the positive rates were up to 12.9% and 12.7% respectively, which formed the higher peak. Lower one was observed during July to August. From the above results, the actual time of Ascaris reinfection were November to December for the higher peak and May to June for the lower one in Korean population. Pickled vegetable was suggested as a most probable source of Ascaris reinfection during late autumn to winter season.

Journal Article↗