Calcium channel subtypes for the sympathetic and parasympathetic nerves of guinea-pig atria

1. The Ca2+ channel subtypes of the autonomic nerves of guinea-pig atria were elucidated by monitoring the effects of specific Ca2+ channel blockers on the negative and positive inotropic responses associated respectively, with stimulation of the parasympathetic and sympathetic nerves. 2. In left atria paced at 2-4 Hz, the negative inotropic effect induced by field stimulation of parasympathetic nerves (in the presence of propranolol) was abolished by omega-conotoxin MVIIC, a blocker of N-type and OPQ subfamily Ca2+ channels. omega-Conotoxin GVIA (an N-type blocker), omega-agatoxin IVA (a P-type blocker), nifedipine (an L-type blocker) and Ni2+ (a T- and R-type blocker) were much less effective. 3. The positive inotropic response resulting from field stimulation of the sympathetic nerves (in the presence of atropine) was abolished by both omega-conotoxins, while omega-agatoxin IVA, nifedipine and Ni2+ were ineffective. 4. In the spontaneously beating right atria, the early negative inotropic effect produced by 1,1-dimethyl-4-phenylpiperazinium was abolished by omega-conotoxin MVIIC, whereas the late positive inotropic effect was partially reduced, but not abolished, by a high concentration of omega-conotoxin GVIA. 5. None of the peptide toxins affected the chronotropic and the inotropic responses evoked by carbachol and isoprenaline. 6. These results suggested that, under physiological conditions, the release of acetylcholine from parasympathetic nerves is dominated by an OPQ subfamily Ca2+ channel while that of noradrenaline from sympathetic nerves is controlled by an N-type Ca2+ channel. Ligand-induced noradrenaline release appeared to recruit additional type(s) of Ca2+ channel.

Physiological and regenerative acetylcholine release from motor nerve: differential inhibitions by vesamicol and omega-agatoxin IVA

Stimulation of mammalian motor neurons can elicit Ca(2+)-dependent regenerative release of acetylcholine and prolonged endplate depolarization when the enzymatic degradation of the neurotransmitter is inhibited. Unlike physiological phasic release of acetylcholine, the regenerative release is sensitive to L-type Ca2+ channel blockers. We studied the effects of vesamicol (an inhibitor of active transport of acetylcholine into synaptic vesicles) and omega-agatoxin IVA (a blocker of the motor nerve P-type Ca2+ channel) on these two types of acetylcholine release to compare the vesicle pools and Ca2+ channels responsible for the release. When coupled with repetitive stimulations, vesamicol decreased mean amplitude of miniature endplate potentials, resulting in a skewed distribution to lower amplitude, reduced quantal content of endplate potentials and decreased immediate available pool of acetylcholine. omega-Agatoxin IVA had no effect on miniature endplate potential but inhibited quantal content of endplate potential. The mean inhibitory concentration was around 5-10 nM. Vesamicol and omega-agatoxin IVA decreased the probability of triggering regenerative release. However, the magnitude and duration of regenerative release, once triggered, were not depressed by either agent. It appears that the majority of Ca2+ necessary for regenerative release is translocated via omega-agatoxin IVA-insensitive Ca2+ channels, which can be activated by prolonged depolarization of nerve terminals induced by accumulated acetylcholine. The results suggest that different Ca2+ channels are activated in the regenerative (L-type) and phasic (P-type) acetylcholine release, which utilize different pools of synaptic vesicles.

Two human cases of Thelazia callipaeda infection in Korea

Thelazia callipaeda were observed from a 7-month old baby who lived in Uijongbu in 1989 and from a 42-year old man who lived in Anyang in 1994. These are the 23rd and 24th records of human thelaziasis in Korea as the literature are concerned.

Activity-dependent reduction in voltage-dependent calcium current in a crayfish motoneuron

The effect of increased impulse activity upon voltage-dependent Ca2+ currents was studied in the cell body of a crayfish phasic motoneuron using two-electrode voltage-clamp technique. Increased electrical activity in this relatively inactive motoneuron produces a short-term and long-term reduction in the voltage-dependent Ca2+ current. Both forms of activity-dependent reduction in Ca2+ current are Ca2+ dependent. The short-term reduction in Ca2+ current appears to involve the Ca(2+)-dependent inactivation of Ca2+ channels, previously described in a variety of neurons. The long-term reduction in Ca2+ current is produced by prolonged Ca2+ influx and persists for days: in vivo stimulation of the phasic motor axon at 5 Hz for 1 hr results in a 30% reduction in Ca2+ current density, which persists for at least 3 d. Both the short-term and long-term reductions in Ca2+ current appear to result from changes in a single type of high-voltage-activated (HVA) Ca2+ channel. Inhibition of protein synthesis attenuates the long-term reduction in Ca2+ current and has no effect upon the short-term Ca2+ current reduction. During the long-term reduction in Ca2+ current, it appears that Ca2+ channels located distant to the site of Ca2+ influx are affected. The relationship of these results to a previously described Ca(2+)-dependent reduction in transmitter release is discussed.

Inhibition of acetylcholine release from mouse motor nerve by a P-type calcium channel blocker, omega-agatoxin IVA

1. The effects were studied of the central neurone P-type Ca2+ channel blockers, omega-agatoxin IVA, omega-conotoxin MVIIC (polypeptide toxins) and synthetic funnel-web spider polyamine toxin on acetylcholine release from mouse motor nerve. 2. omega-Agatoxin IVA decreased the quantal content of endplate potentials and blocked synaptic transmission in the nanomolar range in a reversible manner, whereas the other toxins depressed transmission in the hundred micromolar range. 3. The polyamine toxin, but not the polypeptide toxins, decreased the amplitude of the miniature endplate potential. The increase in the frequency of miniature endplate potentials evoked by high [K+], but not that evoked by alpha-latrotoxin, was effectively antagonized by omega-agatoxin IVA. 4. In the presence of omega-agatoxin IVA, high frequency nerve stimulation produced facilitation of endplate currents and tetanic contractions. 5. The results suggest that, under physiological conditions, the Ca2+ necessary for nerve action potential-evoked acetylcholine release is translocated via a subtype of the P-type Ca2+ channel sensitive to omega-agatoxin IVA.

Vaninolol: a novel compound for the treatment of glaucoma and ischemic retinopathy

Vaninolol has been confirmed as a selective beta 1-adrenergic blocking agent. The new compound was studied for its effects on intraocular pressure (IOP), the ocular blood flow and the retinal function in this report. Vaninolol showed marked delay in IOP recovery demonstrating that the agent possessed an ocular hypotensive action. This effect is equipotent or slightly more active than L-timolol. In addition, effects of vaninolol on the ocular blood flow of ocular hypertensive eyes were determined using the colored microspheres technique. It was found that vaninolol improved the ocular blood flow in ciliary body and retina, but not in iris and choroid. Further, vaninolol is able to improve the b-wave recovery in electroretinography significantly, indicating that it is possible to develop a new agent for the treatment of ischemic retinopathy.

Decay studies of DMPO-spin adducts of free radicals produced by reactions of metmyoglobin and methemoglobin with hydrogen peroxide

The 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) spin adduct of myoglobin (Mb) or hemoglobin (Hb) was formed when metmyoglobin (MetMb) or methemoglobin (MetHb) reacted with H2O2 in the presence of DMPO, and both decayed with half-life of a few minutes. The DMPO spin adduct of Mb decayed with biphasic kinetics with k1 = 0.645 min-1 and k2 = 0.012 min-1, indicating that the spin adduct consisted of two kinetically heterogeneous species, stable and unstable ones. The DPMO spin adduct of Hb, however, was homogeneous. Decay of both spin adducts was accelerated in the presence of tyrosine, tryptophan or cysteine, but not phenylalanine, methionine or histidine. The decay obeyed the first order kinetics at varying concentrations of the spin adducts. The decay was accelerated by denaturation and proteolysis of protein moiety. The decay rate was not affected by the extra addition of MetMb or MetHb to each spin adduct. The decay rate of the spin adduct of Mb was increased by hematin in the presence of H2O2 and decreased by catalase. Decay of stable spin adduct of Mb, however, was not significantly changed under any experimental conditions used. These results led us to conclude that instability of the DMPO-spin adducts of Mb and Hb is due to intramolecular redox reactions between the spin adducts and amino acid residues and/or products of the reaction between heme and H2O2.

Use of C1300 neuroblastoma cells to evaluate the protective value of hexamethonium, trimethaphan, hemicholinium, and triethylcholine against diisopropyl phosphorofluoridate toxicity

Our intent was to evaluate the C1300 neuroblastoma cell as an in vitro system for studying the mode of action and efficacy of drugs used to treat or prevent organophosphate intoxication. The anticholinergic drugs hexamethonium, trimethaphan, and hemocholinium and the triethylcholine and cholinesterase/reactivator 2-pyridine aldoxime methochloride (2-PAM) have been shown to be effective in preventing intoxication by diisopropyl phosphorofluoridate (also known as diisopropyl fluorophosphate, DFP) in vivo. We determined their efficacy in preventing cell death (as measured by trypan blue exclusion) of neuroblastoma cells alone or in combination. We also determined their efficacy in reversing the cytotoxic effects of DFP on cell DNA synthesis (as measured by [3H]-thymidine incorporation), cell RNA synthesis (as measured by [3H]uridine incorporation), and on cell protein synthesis (as measured by [3H]leucine incorporation). The maximal nontoxic doses of the drugs in vitro were determined. All anticholinergic agents studied reduced the cytotoxicity of DFP using one or more parameters. 2-PAM, the cholinesterase reactivator, enhanced the cytotoxicity of DFP on cultured cells at a high concentration (1 mg/mL) and reduced it at a lower concentration (0.3 mg/mL). All four anticholinergic agents were capable of enhancing the uptake of [3H]thymidine. Only hexamethonium and hemicholinium reversed DFP inhibition of DNA synthesis. RNA synthesis was not affected by any anticholinergic agent and no agent reversed DFP inhibition of RNA synthesis. Protein synthesis was enhanced by every anticholinergic agent except hemicholinium; the inhibition of protein synthesis by DFP was reversed by trimethaphan and triethylcholine.(ABSTRACT TRUNCATED AT 250 WORDS)

Egg positive rates of Clonorchis sinensis and intestinal helminths among residents in Kagye-ri, Saengbiryang-myon, Sanchong-gun, Kyongsangnam-do

Stools of the residents in a village in Saengbiryang-myon, Sanchong-gun, Kyongsangnam-do were examined for the eggs of intestinal helminths. In 1987, infection rate of 76 residents by Clonorchis sinensis was 80.3% with mean eggs per gram of feces (EPG) 27,781. C. sinensis-infected persons were treated once with praziquantel 60 mg/kg, q.i.d. Seventeen persons (22.4%) infected by Metagonimus yokogawai was coinfected with C. sinensis. In 1993, C. sinensis egg positive rate was 48.4% with mean EPG 5,929. Reinfection rate of follow-up cases by C. sinensis was 55.2% during 5 years and 5 months. Infection rate by M. yokogawai was 3.2%. This village was an endemic focus of clonorchiasis occurring reinfection high.

Facilitation of nicotinic receptor desensitization at mouse motor endplate by a receptor-operated Ca2+ channel blocker, SK&F 96365

When acetylcholinesterase was inhibited by neostigmine, SK&F 96365 (1-(beta-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl)-1H-imidazole hydrochloride) at 10 microM caused no effect on the amplitude of single endplate potentials (e.p.p.s) but shortened the decay time in mouse phrenic nerve-diaphragm preparations. However, SK&F 96365 inhibited high-frequency stimulation-evoked long-lasting depolarization of the endplate region and accelerated the run-down of trains of e.p.p.s which were eliminated within 1 s. After a train of stimulation, SK&F 96365 produced a post-tetanic depression of single e.p.p.s. The post-tetanic effect gradually dissipated with full restoration in 10-15 s. During a train of stimulation, SK&F 96365 also depressed miniature endplate potentials (m.e.p.p.s), which were restored after termination of stimuli in parallel with the recovery of e.p.p. The decay times of miniature endplate currents during recovery phases changed slightly. In control preparations not treated with neostigmine, however, SK&F 96365 did not alter the amplitude and decay time of m.e.p.p.s or e.p.p.s but accelerated the decay of succinylcholine-induced endplate depolarizations. The results suggest that SK&F 96365 facilitates nicotinic receptor desensitization in addition to blocking receptor-operated Ca2+ channels.

Intestinal trematode infections in the villagers in Koje-myon, Kochang-gun, Kyongsangnam-do, Korea

An epidemiological study for the intestinal trematode infection of the villagers was done in Koje-myon, Kochang-gun, Kyongsangnam-do, Korea in March, 1994. Of 116 stool specimens examined, total helminthic ova positive cases were 13 (11.2%) and cumulative ova positive cases 21 (18.1%): Echinostoma hortense 11 cases (9.5%), Metagonimus sp. 6 cases (5.2%), and Clonorchis sinensis 4 cases (3.4%). After the treatment and purgation, variable numbers of E. hortense, 6 to 227 per person, were collected from 7 echinostome egg positive cases, together with M. takahashii in 6 cases. Three adult flukes of E. cinetorchis were collected from one person and one Stellantchasmus falcatus was recovered from another case. This mountainous village was proved to be one of the endemic foci of echinostomiasis in Korea.

Liver function in Clonorchis sinensis-infected rabbits

Nine rabbits were fed with Clonorchis sinensis metacercariae (MC) and the blood samples chronologically obtained were analyzed biochemically. Rabbits infected by less than 100 flukes were grouped into Group I, and by 100-250 flukes into Group II. The serum level of alanine aminotransferase (ALT) was increased from 3 weeks after the infection of the metacercariae (AIM) and showed a peak at 8 weeks, and decreased from 12 weeks AIM. The serum level of aspartate aminotransferase (AST) was raised to 92.3 +/- 65.4 U/L at 3 weeks AIM and stayed high until 8 weeks, then lowered thereafter. The serum level of gamma-glutamyl transpeptidase (gamma-GT) was increased rapidly to the highest value (18.9 +/- 14.6 U/L) at 16 weeks AIM, and decreased to the control level after 20 weeks. The serum level of alkaline phosphatase (ALP) was headed down from the early infection to 52 weeks AIM. The serum cholesterol level was increased from 8 weeks and reached at a peak 16 weeks AIM, and decreased thereafter to the control level. It is suggested that serum ALT, AST, ALP and gamma-GT tests be useful to diagnose the early infection of C. sinensis.

Treatment response with transurethral radiofrequency thermotherapy for symptomatic benign prostatic hyperplasia

One hundred and two patients with benign prostatic hyperplasia were treated by transurethral radio-frequency thermotherapy (TURT) device (Thermex-II, Direx, Israel) with 47.5 degrees C in single session for 2 hours and 30 minutes from November 1992 to October 1993. Among them, 83 patients, who were followed up for more than 3 months were included in this study. Twenty-seven (32.5%) patients had a history of acute retention. Pretreated values of the mean Madsen-Iversen symptom score, maximum urine flow rate, postvoiding residual urine volume, prostate volume and prostate specific antigen (PSA) were 15.4, 6.5 ml/sec, 61.3ml, 43.2ml and 0.77 ng/ml respectively. Madsen-Iversen symptom score, maximum urine flow rate were measured at 2 weeks, 1, 3 and 6 months after TURT. The residual urine volume, prostate volume and PSA level were measured at 3 and 6 months after TURT. During the follow up, the symptom score started to decrease significantly at 1 month (9.9, p < 0.01) after TURT, and gradually decreased up to 6.9 at 3 months. The maximum flow rate showed initial significant improvement at 2 weeks (8.1 ml/sec., p < 0.01), but no significant interval change was observed thereafter. The residual volume decreased significantly at 3 months (41.3 ml, p < 0.01) and no decrement was noted until 6 months. Neither the prostate volume nor PSA value changed significantly at 3 or 6 months after TURT. The improvement, which was defined as a change of 50% or more in at least one of subjective or objective symptoms showed in 63.9% (53/83) at 3 months and 57.1% (32/56) at 6 months. Both subjective and objective improvements at 3 and 6 months after treatment showed in 24.1% and 19.6%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Testosterone productivity and histostructural changes of autotransplanted rat Leydig cells

To investigate the possibility of in vivo transplantation of Leydig cells as a new biologic androgen replacement therapy, the Leydig cells procured from 6 week-old male Sprague-Dawley rats were autotransplanted, and the level of testosterone secretion and histostructural changes were observed. The renal subcapsular and intraperitoneal transplant showed higher levels of testosterone compared to subcutaneous or scrotal counterparts, and the number of transplanted cells was correlated with the level of measured testosterone. Furthermore, if the Leydig cells were transplanted intraperitoneally after the uptake on synthetic collagen, testosterone levels were higher than the ones simply transplanted without synthetic collagen uptake, resulting in 27 fold increase at 3 months. The activity of 125I-hCG decreased 20 to 40% at each month after transplantation compared to the normal levels, but no statistical significance was noted among different periods. The histologic examination revealed neovascularized capillaries and well demarcated sheet-like group of eosinophilic Leydig cells were observed at 4 weeks. But the evidence of destructive changes such as a focal inflammation with central dystropic ossification could be noted after 3 month. On electron microscopy, the marked indentation of nucleus and presence of lipochrome pigment were seen, and the number and size of smooth endoplasmic reticulum and mitochondria were reduced after 3 month. In conclusion, testosterone output could be increased to the physiologic range by increasing the number of transplant cells or utilizing collagen uptake but further effort is necessary on delaying or preventing the structural and functional decrement of Leydig cells.

A clinical consideration of systemic embolism complicated to infective endocarditis in Korea

OBJECTIVES

Infective endocarditis is still one of the important fatal diseases in Korea, especially when systemic embolisms are supervene. So, identification of patients who are in the high risk of embolism and who can be helped by early surgical intervention is very important. Considering these, we tried to elaborate the risk factors for the systemic embolism in patients with an infective endocarditis and the influence of systemic embolism on the mortality and morbidity in patients with an infective endocarditis.

METHODS

We retrospectively reviewed the clinical records of 97 patients who were admitted with the infective endocarditis between January 1983 and October 1993.

RESULTS

Among 97 patients, 80 patients met our diagnostic criteria. The mean age of patients was 38 years old. There were 43 males and 37 females. The mean duration of fever since the fever developed by history was 38 days. Valvular heart disease was the most frequent underlying heart disease. Mitral regurgitation and aortic regurgitation were the most common among valvular heart diseases. Pneumonia and acute pharyngotonsillitis were the most frequent predisposing factors of infective endocarditis. Blood cultures were positive in 51 patients (63.8%). Streptococcus viridans was the organism isolated most frequently, and Staphylococcus aureus was the second most frequently isolated one. Vegetations were detected in 58 patients (76.3%) by an echocardiography. Mitral valve and aortic valve were the most frequently involved incidence rate of embolism was 50% and the most frequent embolism site was the central nervous system and extremities were the next. Embolism occurred at the mean of 37 days after onset of fever. Overall in-hospital mortality rate was 26.3% and a cardiac-origin was the major cause of death. The only statistically significant risk factor for mortality was systemic embolism. The analysis of the relation between an incidence of embolism and the multivariables (age, presence of vegetation, location of vegetation, size of vegetation, causative organisms) showed that only the growth of Staphylococcus aureus had a significant trend toward a risk of subsequent systemic embolism.

CONCLUSION

This study suggests that systemic emboli increases the mortality rate in patients with infective endocarditis. Age of patients, presence of vegetation, size and location of vegetation are not the risk factors for embolism, while certain organism, especially Staphylococcus aureus, could be a risk factor for the systemic embolism.

A fetal rat urogenital sinus mesenchymal cell line (rUGM): accelerated growth and conferral of androgen-induced growth responsiveness upon a human bladder cancer epithelial cell line in vivo

A cell-cell interaction model was developed to examine the intercellular communication between mesenchymal and epithelial cells in vivo, and to define the role of androgen and paracrine growth factors in promoting growth and differentiation of the target epithelial cells. Using this model system, we have demonstrated that, in the presence of androgenic steroids, a fetal urogenital sinus mesenchymal cell line exhibited androgen-induced growth responses which resulted in an induction of growth of a non-androgen target epithelial cell line derived from human urinary bladder. Our results show that: (1) a rat fetal urogenital sinus mesenchyme-derived cell line (rUGM) accelerated growth and conferred androgen-induced growth responsiveness upon a non-androgen target cell line, WH, derived from a human bladder transitional-cell carcinoma (TCC); this induction of epithelial tumor growth in vivo occurred in a fibroblast-specific manner; (2) live fetal rUGM cells are required to promote WH tumor growth in vivo, which suggests that continuous production of factors that may serve as mediators for paracrine/autocrine pathways are responsible for androgen stimulation of WH tumor growth in vivo; and (3) although WH tumor growth, mediated by the presence of rUGM cells, was markedly accelerated by the presence of androgen in vivo, androgen and rUGM cells failed to promote the expression of a human prostate-specific antigen (PSA) by WH tumors in vivo. Our results emphasize the importance of organ-specific fibroblasts that promote tumor growth and mediate androgen-induced growth responses; the accelerated growth of the bladder epithelium was not accompanied by the expression of PSA, a known differentiated gene product produced by human prostatic epithelial cells. This report also discusses the potential significance of mesenchymal-epithelial cellular interaction which mediates androgen action and may play an important role by influencing human prostate tumor growth, progression and differentiation.

Correlation between blood pressure changes assessed by 24-hour ambulatory blood pressure monitoring and urine microalbuminuria excretion rate in normal and essential hypertension

To document the correlation between renal damage and circadian blood pressure variation, urinary microalbumin excretion rate (UAER) and 24-hour ambulatory blood pressure monitoring (24-hr ABPM) were performed in 16 normotensives and 29 stage I-III essential hypertensive subjects (whole-day mean BP; 120.13/79.06 mmHg vs 152.59/94.31 mmHg, p < 0.05). The BP variables of 24-hr ABPM included hourly mean arterial pressure (MAP), maximum, minimum and mean systolic and diastolic BP of the awaking (daytime) and sleep time (nighttime), and whole-day mean BP. Subsequently, BP reduction of maximum, minimum and mean BP between awaking time and sleep time were also calculated as other variables. UAER was not different between the normotensive and hypertensive group (9.44 +/- 11.48 vs 11.87 +/- 9.27 micrograms/min, p > 0.05). 10 subjects (2/16 in normal vs 8/29 subjects in hypertensives) revealed over 16 micrograms/min of UAER. All of the awaking BP variables and whole-day mean BP were correlated with the UAER in whole subjects and hypertensives, but almost sleep BP variables except maximum DBP and mean DBP were not. On the contrary, only daytime minimum DBP and SBP were correlated with UAER in normotensives. The common best correlated BP variable in awaking time was minimum BP (DBP and SBP; r = 0.49, r = 0.44 in whole, r = 0.51, r = 0.58 in hypertensives, r = 0.54, 0.56 in normotensives, all p < 0.05). Hourly MAP at 24 PM in whole subjects (r = 0.49, p < 0.05) and that of at 22 PM in hypertensives were best correlated (r = 0.71, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Epidermal growth factor receptor-mediated autocrine and paracrine stimulation of human transitional cell carcinoma

Stromal-epithelial interactions may play a key role in tumor growth and metastasis. We have established a model to study the cellular and molecular basis of this paracrine interaction both in vivo and in vitro using a human transitional cell carcinoma cell line (WH). s.c. coinoculation of 1 x 10(6) WH cells with 1 x 10(6) nontumorigenic fetal rat urogenital sinus mesenchymal (rUGM) cells in athymic mice accelerated carcinoma growth 20 times faster than isolated WH cell inoculations and 4 times faster than coinoculations of the same number of NIH-3T3 or human bladder fibroblasts. Characterization of these chimeric tumors with immunohistochemical and DNA dot-blot analyses documented their predominantly human component. To evaluate the underlying mechanisms involved in this paracrine-mediated in vivo tumor growth acceleration, Northern analyses for growth factors (GFs) and extracellular matrix (ECM) expression in the different cell lines, as well as in vitro mitogenic assays, were performed. Northern analysis revealed basic fibroblast growth factor, transforming growth factor alpha, and epidermal growth factor receptor expression by WH cells but not rUGM cells; ECM components (fibronectin and collagens I and IV) were expressed only in the fibroblast cell lines. Cell type-specific paracrine growth factors are produced by cultured stromal and epithelial cells with a 2-3-fold bidirectional increase in WH and rUGM cell growth when cultured with reciprocal cell-type conditioned medium. An autocrine growth loop was observed for WH but not rUGM cells. WH cell growth is stimulated in vitro by low concentrations of transforming growth factor alpha and epidermal growth factor, while rUGM cell growth is stimulated 3-fold by basic fibroblast growth factor. Antiepidermal growth factor receptor antibodies completely inhibited autocrine and paracrine pathways stimulating WH cell growth, while anti-basic fibroblast growth factor antibodies had no inhibitory effect. These observations suggest that autocrine and paracrine growth factor stimulation of WH bladder carcinoma cell growth is most likely mediated by an epidermal growth factor receptor-related pathway. The predominant expression of ECM by fibroblasts in this model suggests that stromal cell ECM components may modulate tumor cell growth and angiogenesis possibly through mechanisms involving cellular adhesion, chemotaxis, or growth factor action.

Clonorchis sinensis tropomyosin: cloning and sequence of partial cDNA amplified by PCR

C. sinensis total RNA was containing large amount of 18S rRNA but little 28S rRNA. The size of the double-stranded cDNA synthesized from poly (A)+ mRNA was 0.4-4.2 kb long with tapering upto 9.5 kb. Degenerated oligonucleotides (as 2 sense and 3 antisense primers) were designed on the conserved regions of the known tropomyosin amino acid sequences. From one out of the PCR amplifications using total cDNA and matrix of primers, a specific gene product, 580 bp in size, was produced. Upon Southern hybridization of the PCR products with Schistosoma mansoni tropomyosin (SMTM) cDNA, only one signal appeared at the band of 580 bp product. This 580 bp product was considered to encode C. sinensis tropomyosin (CSTM) and cloned in pGEM-3Zf(-) for DNA sequencing. CSTM cDNA was 575 bp containing one open reading frame of 191 predicted amino acids, which revealed 86.3% homology with SMTM and 51.1% with Trichostrongylus colubriformis tropomyosin. CSTM cDNA obtained will serve as a probe in the studies of molecular cloning of CSTM.

O2 occlusion and cyanide induced immediate relaxation and contraction of murine skeletal muscle

The acute changes of muscle tone and membrane current upon occlusion of oxygenation (O2 occlusion) were studied in vitro in mouse diaphragms. O2 occlusion immediately produced a contraction and a relaxation, respectively, in ryanodine- and high K(+)-contracted muscles while a biphasic change (an initial decrease then a late increase) of muscle tone was produced in muscles contracted with caffeine. The O2 occlusion effects were reversed after reoxygenation. CN- produced similar acute changes of muscle tone and abolished O2 occlusion effects. The O2 occlusion-induced relaxation in high K+ medium was converted into a contraction by 3,4-diaminopyridine and by low Cl- Tyrode's. O2 occlusion induced a small outward current and membrane hyperpolarization at a rate slower than the changes of muscle tone. Glybenclamide inhibited all of the changes induced by O2 occlusion. It is possible that the K+ and Cl- permeabilities of sarcoplasmic reticulum are highly sensitive to hypoxic challenge and related to the immediate changes of muscle tone after O2 occlusion.

Transmitter-mediated local contracture of the endplate region of the focally innervated mouse diaphragm treated with anticholinesterase

1. Local contraction of the endplate region in response to nerve stimulation was studied in isolated mouse diaphragms. In normal preparations, muscle contractions involved the whole length of the muscle fibre with rise and decay times in the order of tens of ms whether evoked with a single or train of pulses. 2. When acetylcholinesterase was inhibited with neostigmine, tetanic stimulation produced a twitch-like phasic contraction and a delayed tonic contracture. A brief train of pulse (10 ms, 300 Hz) was enough to trigger a full size tonic contracture which reached an amplitude about one tenth that of control tetanus and had a duration of about 4 s. 3. Tetanic stimulation evoked a non-propagating prolonged depolarization at the endplate region lasting for about 1 s following a few muscle action potentials. 4. mu-Conotoxin, a specific inhibitor of muscle Na+ channel, selectively abolished the phasic contraction and the muscle action potentials leaving the tonic contracture and the prolonged depolarization unaffected. 5. Both the tonic contracture and the prolonged depolarization were highly sensitive to blockade by tubocurarine (IC50 0.05-0.1 microM) and vesamicol (1 microM, an inhibitor of packaging acetylcholine into synaptic vesicles), were attenuated by increasing Ca2+ concentration and were prolonged by decreasing Ca2+. 6. The results suggest that prolonged activation of endplate nicotinic receptors by endogenously released transmitter can produce substantial contractions of the endplate region when acetylcholinesterase are inhibited. The source of Ca2+ for the contraction seems to come mainly from intracellular stores.

[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)

Long-term changes in the neuromuscular synapses of a crayfish motoneuron produced by calcium influx

Previous in vivo studies of crustacean neuromuscular synapses have shown that a chronic increase in the impulse activity of a previously 'inactive' motoneuron produces a reduction in initial transmitter release and greater resistance to synaptic fatigue. To explore the mechanisms of this synaptic change, we have developed an in vitro procedure for examining this activity-dependent reduction in initial transmitter release. We report that depolarization selectively applied to the proximal region of the neuron (cell body or axon) of a phasic motoneuron produces a reduction in initial transmitter release from the motor terminals. This synaptic change is observed 4-5 h after the beginning of depolarization. Proximal depolarization decreases initial transmitter release without reducing the capacity of the terminals to release transmitter during repetitive stimulation. Application of a calcium channel blocker during conditioning prevents the reduction in initial transmitter release. These results demonstrate that prolonged calcium influx produce a long-term reduction in initial transmitter release, and that calcium influx in distant regions of the motoneuron can influence transmitter release from motor terminals. The relationship of these findings to previously reported activity-dependent synaptic changes is discussed.

Effects of dopamine agonists and antagonists on pulsatile blood flow of ocular hypertensive rabbits

It has been reported that some dopamine antagonists can suppress the intraocular pressure and can increase the blood flow in the retina and choroid. Therefore, several dopamine antagonists and agonists were studied to determine if they can increase the ocular pulsatile blood flow in ocular hypertensive rabbits with the intraocular pressure raised artificially to 40 mm Hg. It was found that numerous dopamine antagonists including loxapine, moperone, domperidone, haloperidol and metoclopramide increased pulsatile blood flow for 49-110%, 95-155%, 72-86%, 60-114%, and 39-139%, respectively. Floropipamide reduced the ocular pulsatile blood flow for 18% at 90 min and 10% at 120 min. Chlofluperol produced biphasic action on pulsatile blood flow by significantly reducing it initially at 60 min (-49%) and then markedly increasing it at 180 min (91%). In case of dopamine agonists, neither dopamine nor bromocriptine affected the pulsatile blood flow significantly. These results indicate that some of dopamine antagonists could be used to lower the intraocular pressure and to increase the ocular pulsatile blood flow as well.

Surface ultrastructure of Heterophyes nocens (Trematoda: Heterophyidae)

The surface ultrastructure of Heterophyes nocens (Trematoda: Heterophyidae) was studied by scanning electron microscopy(SEM). The adult worms were recovered from experimentally infected cats and from a naturally infected patient. They were leaf-like, ventrally concave, and ovoid or pyriform in shape. Ciliated knob-like sensory papillae (type I) were observed in single or grouped forms on and around the oral sucker, whereas non-ciliated round swellings (type II papillae) were seen on the lip of the ventral sucker. The tegumental spines around the oral sucker were 5-9 pointed, whereas those between the two suckers were 12-17 pointed. Ventrolaterally, three groups of 5-6 type I papillae were located between the oral and ventral suckers, with single ones alternating between them. The genital sucker was protruded or depressed, depending on the contraction state of the flukes, and the gonotyl spine number ranged 50-60. The number of tip points of tegumental spines was decreased posteriorly; finally they became 1-3 pointed. On the dorsal surface, 4 groups of 4-5 type I papillae were symmetrically located on both lateral sides, and the shape and distribution of tegumental spines were similar to those of the ventral surface. Although the tegumental ultrastructure of H. nocens was generally similar to those of other heterophyids, the genital sucker morphology including the number of gonotyl spines and/or the distribution pattern of tegumental spines and sensory papillae were suggested to be the characteristic features of H. nocens.

[Comparative study on the effectiveness of modified Kato's cellophane thick smear and Stoll's dilution egg counting technique for quantitative fecal examination of helminth eggs]

A total of 197 fecal specimens was prepared for quantitative examination of helminth eggs by modified Kato's cellophane thick smear (M.C.T.S.) and Stoll's dilution egg counting technique (D.E.C.T.). The comparative effectiveness of two techniques was evaluated and conversion function was deduced. The average time required for the microscopic examination on one slide by M.C.T.S. was 12.6 minutes and that of D.E.C.T. was 14.6 minutes. M.C.T.S. showed lower false negative rate than D.E.C.T. in light worm burden cases. Functions to convert the counts obtained by M.C.T.S. to E.P.G. by Stoll's dilution egg counting technique were 47.86 x 10(0.87) logM.C.T.S. in A. lumbricoides, 41.69 x 10(0.82) logM.C.T.S. in T. trichiura and 63.10 x 10(0.85) logM.C.T.S. in C. sinensis. It was suggested M.C.T.S. be better than D.E.C.T. for the quantitative examination of intestinal helminthiases such as A. lumbricoides, T. trichiura, and C. sinensis infections even in the cases with low worm burden.

Inhibition by neosurugatoxin and omega-conotoxin of acetylcholine release and muscle and neuronal nicotinic receptors in mouse neuromuscular junction

Neosurugatoxin and omega-conotoxin, known to be specific ligands for the neuronal nicotinic receptor and Ca2+ channel, respectively, were previously claimed to exert no depressant action on the mouse neuromuscular junction. It was found that in preparations partially blocked with tubocurarine or with low Ca(2+)-high Mg2+ Tyrode's, both toxins, at 3-10 microM, depressed indirect twitches and either produced wanings (neosurugatoxin) or waxings (omega-conotoxin) of indirectly elicited tetanic contractions whilst in normal Tyrode's the contractile forces were not changed. In normal Tyrode's, neosurugatoxin decreased the amplitudes of spontaneous and evoked endplate potentials and enhanced the run-down of endplate potentials as did tubocurarine though with lesser potency. By contrast, omega-conotoxin (10 microM) decreased the amplitude of the evoked but not of the spontaneous endplate potential in low Ca(2+)-high Mg2+ Tyrode's, and produced facilitation of endplate potentials, instead of run-down, on repetitive stimulations. Higher concentrations of omega-conotoxin appeared to depress quantal release in normal Tyrode's. The effects were all reversible. The prolonged endplate depolarization found in preparations treated with neostigmine or 3,4-diaminopyridine, was partially depressed by both toxins. The results suggest that neosurugatoxin blocks the neuron and muscle nicotinic receptors in the neuromuscular junction with comparable potency. The pharmacology of the nicotinic receptor on motor nerve terminal seems more similar to the muscle nicotinic receptor than to that on autonomic ganglia or brain. On the other hand, omega-conotoxin seems to block a small fraction of Ca2+ channels on the motor nerve and decreases the quantal release of evoked endplate potentials.

Hyperpolarization of denervated skeletal muscle by lemakalim and its antagonism by glybenclamide and tolbutamide

Innervated skeletal muscles are endowed with K+ channels activatable by K+ channel openers. It is of interest to know whether the denervation-induced depolarization is due to a deficiency of such a K+ channel. In denervated mouse diaphragm, lemakalim, a K+ channel opener, effectively hyperpolarizes membrane and reduces membrane resistance, spontaneous activity as well as twitch force reversibly. Reductions of transmembrane K+ gradient diminish the lemakalim-induced hyperpolarization. In voltage-clamped fiber, lemakalim induces a long-lasting outward current. A current clamp experiment suggests a reversal potential of around -90 mV. On innervated diaphragm, lemakalim hyperpolarizes membrane and increases conductance if the muscle is predepolarized by anodal current. Lemakalim, however, is much less effective in overcoming the depolarization caused by crotamine, which activates Na+ channel. The effects of lemakalim are not attenuated by blockades of membrane Na+, Ca++ and Cl- permeabilities. Glybenclamide and tolbutamide, blockers of ATP-regulated K+ channel, antagonize the effects of lemakalim at low concentrations and produce slight membrane hyperpolarizations in denervated muscle, but marked membrane depolarizations in innervated muscle at higher concentrations. Cs+ depolarizes both innervated and denervated diaphragms and reduces the hyperpolarizing effect of lemakalim. The results suggest that lemakalim hyperpolarizes denervated muscle via glybenclamide sensitive K+ channels. It is inferred that a reduction of membrane K+ conductance rather than an increase of Na+ or Ca++ conductance contributes to the denervation-induced depolarization.

Surface ultrastructure of the developmental stages of Heterophyopsis continua (Trematoda: Heterophyidae)

Ultrastructural observations were made on the tegument of juvenile and adult stages of Heterophyopsis continua using scanning electron microscopy. On the surface posterior to the ventral sucker, the tegumental processes were bandlike in the metacercariae, cobblestonelike in the flukes 2 days postinfection (PI), and velvety at 3 days PI. The anterior surface between the oral and ventral suckers of the metacercariae was packed densely with tegumental spines having a 10- to 14-pointed tip. In flukes 6 days PI, the number of points increased to 15-17. The tegumental spines immediately behind the ventral sucker on the metacercariae surface possessed 5-7 points; posteriorly the points were reduced in size and in number. Ciliate sensory papillae (type I), as single or clumped forms of 2 or 3, were abundant around the oral and ventral suckers of metacercaria and adult worms. The clumped papillae appeared bilaterally symmetrical on the dorsal and ventral surfaces. The ciliate papillae may function in tango-, rheo-, and/or chemoreception. On the lip of the ventral sucker, 6-7 aciliate domed papillae (type II) were arranged in an equidistant manner. At 2 days PI each type II papilla became a clumped form having 2 or 3 papillae. Type II papillae may function as tango- and/or pressure-receptors. The structure and distribution of papillae suggest that the ventral sucker likely functions as a holdfast organ and the oral sucker as a probing organ involved in feeding.

Activity-dependent development of synaptic varicosities at crayfish motor terminals

Tonically and phasically active crayfish motor terminals have well-characterized differences in synaptic physiology. During repetitive activation, the tonic terminals show facilitation and no depression, while the phasic terminals show dramatic synaptic fatigue. It has been proposed that this greater capacity for transmitter release from tonic terminals may be largely due to the presence of large synaptic varicosities along tonic terminals that contain large mitochondria, synapses, and numerous synaptic vesicles. In addition, a recent study indicates that in vivo tonic stimulation of a phasic terminal in young animals increases the fatigue resistance of the neuromuscular synapses and increases the number of synaptic varicosities, as well as the size of mitochondria and synapses. Because these previous morphological studies of crustacean motor terminals were performed using transmission electron microscopy, only short lengths of terminal were observed, and changes in synaptic varicosity frequency and size could not be thoroughly examined. In order to examine the synaptic varicosities along the terminal, motor terminals were injected with HRP, and the morphology of contrast-enhanced light microscopic images was examined. We report here that tonic terminals have much larger and more numerous synaptic varicosities than phasic terminals. In vivo stimulation of a phasic motoneuron results in an increase in the frequency of synaptic varicosities. This represents an increase in the total number of varicosities because terminal length appears to remain constant. These synaptic varicosities appear to form along preexisting terminals and persist for days after the final in vivo stimulation. The results indicate that the greater transmitter-releasing capabilities of tonic terminals compared to phasic terminals are due to their larger and more frequent synaptic varicosities. In addition, the development of these synaptic varicosities is activity dependent.

Run-down of neuromuscular transmission during repetitive nerve activity by nicotinic antagonists is not due to desensitization of the postsynaptic receptor

1. Whether the function of the postsynaptic acetylcholine receptor is use-dependently affected by repetitive nerve stimulation in the presence of competitive antagonists was studied in the mouse phrenic nerve-hemidiaphragm preparation. 2. For electrophysiological experiments, the preparation was immobilized by synthetic mu-conotoxin, which preferentially blocks muscular Na-channels causing neither depolarization of the membrane potential, inhibition of quantal transmitter release, nor depression of nicotinic receptor function. 3. High concentrations of cobratoxin depressed indirect twitches and endplate potentials (e.p.ps) without inducing waning of contractilities or run-down of trains of e.p.ps evoked at 10-100 Hz. However, waning and run-down were accelerated after washout of the toxin despite diminished postsynaptic receptor blockade. Once the run-down of e.p.ps was produced by washout or low concentrations of cobratoxin, further depression of e.p.p. amplitude with high concentrations of cobratoxin did not attenuate the e.p.p. run-down. 4. The degrees of waning of tetanus and trains of e.p.ps produced by a very high concentration of tubocurarine (20 microM) were also less than that caused at a 100 fold lower concentration, albeit the amplitudes of twitches and the first e.p.p. were depressed more rapidly and markedly. 5. Tubocurarine, like cobratoxin, depressed the amplitude of miniature endplate potentials (m.e.p.ps) more than e.p.ps. 6. In contrast to the steepened run-down of successive e.p.ps in the presence of low concentrations of either nicotinic antagonists, the amplitude of m.e.p.ps observed during repetitive stimulation was uniform and was not different from that before stimulation. 7. The results suggest that the e.p.p. run-down and tetanic fade induced by nicotinic antagonists are due to a slow kinetic blockade of presynaptic receptors and confirm that the e.p.p. run-down is not produced by a use-dependent failure of postsynaptic nicotinic receptors. The roles of the presynaptic nicotinic receptor in positive or negative feedback modulations of transmitter release are discussed.

Somatostatin inhibits pepsinogen secretion via a cyclic AMP-independent pathway

Frog esophageal mucosa contains peptide glands which release pepsinogen in response to a variety of secretagogues and serves as a model to examine the inhibitory action of somatostatin. The pepsinogen secretion in response to bethanechol was inhibited by somatostatin in a noncompetitive fashion. The maximal response induced by bethanechol was reduced and the EC50 for bethanechol was increased in the presence of somatostatin. On the other hand, somatostatin showed essentially no effect on pepsinogen release evoked by ionophore A23187, dibutyryl cAMP or by forskolin in the presence of atropine. Atropine was included in the incubation mixture to eliminate the effect of acetylcholine released by forskolin from the intrinsic cholinergic neurons also present in the mucosa. Somatostatin did not exert any significant effect on the basal or the forskolin-stimulated cAMP accumulation in the mucosa, nor the basal or the forskolin-stimulated adenylate cyclase activity in the membranes of the peptic cells isolated from the mucosa. Thus, these results seem to suggest that somatostatin inhibits pepsinogen secretion from frog esophageal mucosa by a cAMP-independent pathway.

Facilitation by 3,4-diaminopyridine of regenerative acetylcholine release from mouse motor nerve

1. Effects of 3,4-diaminopyridine (DAP) on endplate potentials (e.p.ps) were studied in mouse phrenic nerve-hemidiaphragms. 2. In cut muscle preparations, low concentrations of DAP (2-20 microns) increased the amplitude of e.p.ps and shifted the curve relating Ca2+ concentration to e.p.p. amplitude leftward. 3. High concentration of DAP (40-4000 microns) prolonged the duration of e.p.ps dose-dependently up to one hundred fold (ca. 200 ms), yielding, in addition to the normal phasic e.p.p., a prolonged plateau depolarization component which was often preceded by an upstroke depolarization. During the plateau depolarization, nerve stimulations did not evoke any e.p.p. 4. The plateau component of prolonged e.p.ps was suppressed by tubocurarine, verapamil, nifedipine, Mn2+ and Cd2+ (but not by atropine) at low concentrations that had negligible effect on the amplitude of miniature e.p.ps or the phasic component of e.p.ps. Abolition of the plateau component by these agents restored the capability of the nerve terminal to evoke e.p.ps on nerve stimulation. 5. Low concentrations of neostigmine (0.01-0.02 microns) markedly lengthened DAP-prolonged e.p.ps. However, the regenerative endplate depolarization evoked in the presence of high concentrations of neostigmine (0.3-0.5 microns) was not prolonged by DAP. 6. Tetraethylammonium (1 mM) did not provoke prolonged e.p.ps but acted cooperatively with DAP to prolong the duration of plateau depolarization. At a high concentration (3 mM), tetraethylammonium depressed the amplitude of miniature e.p.ps and abolished DAP-prolonged e.p.ps. 7. In uncut muscle preparations, DAP apparently did not modify the time course and amplitude of miniature e.p.ps. Upon direct stimulation by current injection at endplate, DAP increased the muscle action potentials by only about 30%, but induced no prolonged depolarization. 8. These results suggest that the prolonged e.p.ps induced in the presence of DAP are due to a regenerative release of acetylcholine from motor nerve and the induction probably involves a presynaptic Ca2+ channel different from that for normal e.p.ps. It may be inferred that the regenerative acetylcholine release is recruited by Ca2 + channels modulated by nicotinic receptors and K+ channels.

Nicotinic actions of oxotremorine on murine skeletal muscle. Evidence against muscarinic modulation of acetylcholine release

The effects of oxotremorine, arecoline and muscarine on neuromuscular transmission of mouse or rat phrenic nerve-diaphragm were investigated. For some studies of endplate potentials (e.p.p.s) the preparation was immobilized by cutting muscle fibers. Oxotremorine (0.3-10 microM) depolarized endplate membranes, reduced miniature e.p.p. amplitudes but increased frequency, induced spontaneous neural discharges and muscle fasciculations, and produced contracture of denervated mouse diaphragm. In mouse and young rat preparations pretreated with Mn2+, Co2+, Ni2+, Cd2+ or low Ca2+ Tyrode to depress evoked acetylcholine release, oxotremorine 0.3-1 microM increased indirect twitches as well as amplitudes and quantal contents of e.p.p.s. These increases were not observed when the synaptic transmission was not depressed, nor in adult rat preparations. The augmentation by oxotremorine of evoked acetylcholine release persisted in preparations pretreated with neostigmine (1 microM) and tetrodotoxin (20 nM), which inhibited acetylcholinesterase and oxotremorine-induced spontaneous neural discharges. These effects of oxotremorine were mimicked by arecoline but not by muscarine and were antagonized by tubocurarine (0.3 microM) but not by atropine (0.1-10 microM). Atropine alone did not affect indirect twitches, synaptic transmission, tetanic responses evoked by direct stimulation of diaphragms, nor the durations of muscle action potential. The direct twitch responses were only slightly increased by oxotremorine at 2-3 microM. Oxotremorine at high concentrations (greater than 2 microM), depressed indirect twitches and e.p.p. amplitude, and accelerated the run-down of trains of e.p.p.s. The IC50 on indirect twitches was reduced by pretreatment with diltiazem or proadifen, which are known to promote receptor desensitization.(ABSTRACT TRUNCATED AT 250 WORDS)

A new 180 kDa. urine protein marker associated with bladder cancer

We surveyed the tumor-related proteins present in the urine specimens of 118 bladder cancer patients to seek a possible marker enabling future diagnosis and prognosis of this disease. We identified a protein of 180 kDa. by sodium dodecyl sulfate polyacrylamide gel electrophoresis in urine samples subjected to prior adsorption by protein-A conjugated to a sepharose bead. This protein appears to be a glycoprotein because it binds to concanavalin A-conjugated sepharose and can be eluted by alpha-methyl D-mannoside. It does not react immunochemically with antibodies prepared against either carcinoembryonic antigen or epidermal growth factor receptor, both of which have an apparent molecular weight close to 180 kDa. We found this protein in the urine of 74.3% of the patients with transitional cell carcinoma. It was not present in age-matched controls, patients with benign prostatic hyperplasia or patients with 10 other cancers. There was 1 false positive result in a patient with prostate cancer. It does not appear to be associated with urinary tract infection, blood contamination, premedication or anesthesia.

[Intestinal parasite infections among inhabitants in two islands of Tongyeong-gun, Kyeongsangnam-do]

This study was performed to evaluate the status of intestinal parasitic infections among the inhabitants in two islands (Chu-do and Doomi-do) of Tongyeong-gun, Kyeongsangnam-do (Province), from August to September, 1989. A total of 189 stool specimens was collected from the inhabitants of 3 villages and examined by Kato's cellophane thick smear and formalin-ether sedimentation techniques. Stoll's dilution egg counting technique was done for the quantitative examination of helminth eggs. The overall positive rate of intestinal parasites was 30.2%. The egg positive rate of Ascaris lumbricoides was 2.1%, that of Trichuris trichiura 24.3%, hookworm 2.1%, Trichostrongylus orientalis 0.5%, Clonorchis sinensis 1.1%, heterophyid 1.6%, and Taenia species 2.6%. The cyst positive rate of Giardia lamblia was 1.6% and that of Entamoeba coli 0.5%. In T. trichiura infection, the egg positive rate of females (29.9%) was much higher than that of males (17.2%). Among the age groups, 10-19 year group showed the highest infection rate, 32.4%. It was revealed that the prevalence of intestinal parasitic infections among the inhibitants of remote islands should be still high in comparison with ever-reported ones in urban or rural areas.

Recovery rate, growth and development of Heterophyopsis continua in experimental chicks

The growth and developmental pattern of H. continua was observed after experimental infection of their metacercariae to chicks. The recovery rate of worms from the chicks at 1 to 28 days post-infection (PI) was 12.8% in average. The rate remained fairly high for early 4 days of infection but decreased thereafter rapidly till 28 days PI. Most of the flukes, 91.9%, were recovered from the ileum of the chicks. In metacercariae, genital organs such as the ovary, testes, seminal vesicle, seminal receptacle and genital sucker were recognizable. At one day PI Mehlis' gland appeared, and at 2 days follicular vitellaria were observed. At 3 days PI, eggs were formed in the uterine tubule and increased in number as the worm grew old. The worms reached 2,990 microns in length and 525 microns in width at 28 days PI. Genital organs developed rapidly in early stages of infection but slowly thereafter to 28 days PI, whereas non-genital organs developed steadily through the infection period. It was proved by this experiment that chicks should be a moderately suitable final host of H. continua.

The role of mammography on breast cancer patients in a hospital setting

From Oct. 1, 1983 to May 31, 1988, 6198 mammograms were taken and 443 mastectomies were performed at the Yonsei University Hospital, Seoul, Korea. Of these, 191 cases had preoperative mammography performed prior to surgery (study group) and 252 cases underwent mastectomies without preoperative mammography (control group). There were no significant differences between the two groups in pathological stages, axillary lymph node metastasis and size of the tumor, suggesting that little benefit is derived from the preoperative mammography in the hospital setting. However, there were a number of other findings, including a 14% incidence of multiple foci and localization of non-palpable cancer in 3% of cases, that could help us to make therapeutic plans and strategies for these patients.