[Effects of exercise on mitral regurgitation in healthy subjects]

Transthoracic echocardiography including color Doppler echocardiography and graded exercise (supine bicycle ergometer) were performed to examine both the changes of mitral regurgitation (MR) flow during exercise and the effects of cathecholamine on the MR flow in 20 young males (mean age 19 years) and 9 male long-distance runners (mean age 20 years) with presumably normal hearts. MR flow was detected in 13 of the 20 young males at rest. The severity of MR was mild in 12 subjects, and moderate in 1. After exercise, MR flow vanished in 4 of the 13 subjects (group B). In the other nine subjects, MR flow lasted during and after exercise (group A). In the seven subjects without MR flow at rest, MR flow did not appear during and after exercise (group C). Group A had significantly lower left ventricular ejection fraction than group C at rest (A 64.9 +/- 4.25%, B 69.4 +/- 4.32%, C 73.9 +/- 3.46%; p < 0.05). However, no significant differences were observed in other echocardiographic parameters (including left ventricular end-diastolic dimension, mitral annulus diameter and left atrial diameter), heart rate and serum cathecholamine levels between the three groups before and after exercise. In the nine male long-distance runners, MR flow was detected in six of nine subjects at rest. The severity of MR was mild in all subjects. After exercise, MR flow vanished in two of these six subjects (group A). In the other four subjects, MR flow lasted during and after exercise (group B). In three subjects without MR flow at rest, MR flow did not appear during and after exercise (group C). There were no significant differences in echocardiographic parameters, heart rate and serum cathecholamine levels between the three groups before and after exercise. These data suggest that MR flow detected in healthy subjects correlates with tension and contractility of papillary muscle.

Determination of the O/M ratios of polynary uranium oxides by Ce(IV)-Fe(II) back titration after dissolution in mixed sulphuric and phosphoric acids

Uranium (IV) in polynary uranium oxides is determined after the solid has been dissolved in a warm mixed solution of sulphuric and phosphoric acids containing excess Ce(IV). The latter is titrated with a Fe(II) standard solution using ferroin as indicator. This method is especially effective for (mixed) uranium oxides which are difficult to dissolve in hot Ce(IV) sulphuric acid. The standard deviation of the determined x value in polynary oxides is estimated to be below +/- 0.004 for samples of 10-30 mg.

Notched T wave as evidence of autonomic nervous lability in Duchenne progressive muscular dystrophy

We investigated the significance of notched T waves on the ECG in 30 patients with Duchenne progressive muscular dystrophy (DMD) and 50 age-matched controls using noninvasive cardiovascular examinations and measurement of urinary catecholamines. Notched T waves were more frequently observed in patients with DMD than in control subjects (46.7% vs. 20.0%, p < 0.05). Moreover, their frequency was age-independent in DMD, whereas they decreased with age in controls. Patients with notched T waves showed significantly increased heart rate, prolonged QTc and augmented excretion of urinary adrenaline compared with patients without them. There were no significant differences in casual BP or incidences of characteristic UCG abnormalities, such as mitral valve prolapse, and ECG abnormalities, such as tall R waves in the right precordial leads, between DMD patients with and without notched T waves. These findings suggest that notched T waves are associated with accelerated sympathetic nervous activity rather than progressive cardiac involvement in DMD.

Coronary dilating effects of intracoronary nicorandil. Comparison with isosorbide dinitrate

Although nicorandil, N-(2-hydroxyethyl) nicotinamide dinitrate, is a nitrate ester, its cardiovascular action differs from that of nitrate compounds in several aspects. In this quantitative angiographic study, the acute coronary dilating effect of intracoronary nicorandil (0.25, 0.50, 1.0 mg) was compared with that of isosorbide dinitrate (ISDN; 1.0 mg) in 46 patients with or without ischemic heart disease (IHD). Dose-dependent right coronary dilating action was observed by intracoronary administration of nicorandil without any adverse effects. The same degree of right coronary dilation was achieved by the intracoronary application of equivalent doses of ISDN. We conclude that intracoronary administration of nicorandil is beneficial for the supportive treatment of IHD during coronary artery investigation and intervention without the risk of severe systemic hypotension.

A comparison of Echinostoma trivolvis and E. caproni using random amplified polymorphic DNA analysis

The random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) technique was applied to two closely-related echinostome species, Echinostoma trivolvis and E. caproni, demonstrate interspecific polymorphisms of genomic DNA. Band patterns generated using five individual primers showed that these two echinostomes were genetically distinct, although they share genomic DNA to some extent.

Cytochemical localization of cytochrome c oxidase activity in mitochondria in the tegument and tegumental and parenchymal cells of the trematodes Echinostoma trivolvis, Zygocotyle lunata, Schistosoma mansoni, Fasciola gigantica and Paragonimus ohirai

Cytochrome c oxidase in the mitochondria of the tegument and tegumental and parenchymal cells was examined cytochemically in Echinostoma trivolvis, Zygocotyle lunata, Schistosoma mansoni, Fasciola gigantica and Paragonimus ohirai, trematodes that inhabit different sites in their vertebrate hosts. Clear differences in enzyme activity occurred in the mitochondria of these species, probably reflecting the different energy metabolisms of these worms. Marked aerobic metabolism occurred in S. mansoni and P. ohirai adults that inhabit the host mesenteric veins and the lungs, respectively. The tegument and parenchymal cells of S. mansoni possess relatively few, small mitochondria with tabular cristae which are heavily reactive for cytochrome c oxidase. In P. ohirai, the activity for cytochrome c oxidase in tegumental mitochondria increased gradually from juveniles to adults, reflecting that the respiratory activity increased with growth and the aerobic metabolism is activated when the worms reach the lung. P. ohirai juveniles and adults had two types of mitochondria with different shapes and enzyme activities that were located in two different types of parenchymal cells. The intestinal species, E. trivolvis had mitochondria in the basal aspect of the tegument, and some variations in enzyme activity of their mitochondria in the tegumental and parenchymal cells were observed, suggesting that they possess both aerobic and anaerobic metabolic systems. Z. lunata that live in rodent caeca are devoid of mitochondria in the tegument and have many characteristic mitochondria with undeveloped cristae in the parenchymal cells. Mitochondria of F. gigantica showed weak or no activity for cytochrome c oxidase, suggesting that the worm is well-adapted to an anaerobic environment in the host bile duct.

Cloning and sequencing of some genes responsible for porphyrin biosynthesis from the anaerobic bacterium Clostridium josui

The 6.2-kbp DNA fragment encoding the enzymes in the porphyrin synthesis pathway of a cellulolytic anaerobe, Clostridium josui, was cloned into Escherichia coli and sequenced. This fragment contained four hem genes, hemA, hemC, hemD, and hemB, in order, which were homologous to the corresponding genes from E. coli and Bacillus subtilis. A typical promoter sequence was found only upstream of hemA, suggesting that these four genes were under the control of this promoter as an operon. The hemA and hemD genes cloned from C. josui were able to complement the hemA and hemD mutations, respectively, of E. coli. The COOH-terminal region of C. josui HemA and the NH2-terminal region of C. josui HemD were homologous to E. coli CysG (Met-1 to Leu-151) and to E. coli CysG (Asp-213 to Phe-454) and Pseudomonas denitrificans CobA, respectively. Furthermore, the cloned 6.2-kbp DNA fragment complemented E. coli cysG mutants. These results suggested that both C. josui hemA and hemD encode bifunctional enzymes.

Relation between QT and RR intervals in patients with bradyarrhythmias

OBJECTIVE

To investigate the relation between QT and RR intervals in the sick sinus syndrome or high degree atrioventricular block.

PATIENTS

32 patients with episodes of prolonged RR intervals (> or = 2.6 s) on Holter electrocardiographic recordings.

DESIGN

QT and RR intervals were measured manually every 100 to 150 beats on electrocardiographic strips reprinted from the Holter tape over 24 hours. The slope of the QT/RR relation was determined by the linear regression equation for RR intervals < or = 1.4 s (slope 1) and > 1.4 s (slope 2).

RESULTS

Slope 2 (0.0068 (0.0030)) was significantly lower than slope 1 (0.0824 (0.0059), P < 0.0001) in the overall patient population. Slopes 1 and 2 were significantly lower (P < 0.001) in the 23 patients with QT intervals at the preceding RR interval of 1 s (QT1s) of < 0.44 s (0.0692 (0.0053) and 0.0019 (0.0030), respectively) than in the nine patients with QT1s intervals > or = 0.44 s (0.1159 (0.0091) and 0.0194 (0.0055), respectively). Slopes 1 and 2 correlated positively with QT1s interval in all patients.

CONCLUSIONS

The QT/RR relation was comparatively flat when the RR interval was prolonged. Patients with prolonged QT intervals showed exaggerated prolongation of the QT interval with prolonged cycle lengths when compared with patients with normal QT intervals.

Effects of ajmaline on non-sodium ionic currents in guinea pig ventricular myocytes

The lack of currently available data stimulated us to investigate the electrophysiological effects of ajmaline, a classical class Ia antiarrhythmic agent, on various currents responsible for the action potential plateau and repolarization phases. The whole cell patch clamp recording technique was applied to guinea pig ventricular myocytes. Ajmaline suppressed the Ca2+ current (Ica) in a dose-dependent manner (Kd = 1.2 x 10(-5) M) without affecting the steady-state inactivation kinetics and the voltage dependency of the current-voltage relationship. Ajmaline inhibited the inward portion of the inward rectifying K+ current (IKl). Ajmaline decreased the delayed rectifier K+ current (IK) without altering the activation or deactivation time courses. All these inhibitory effects of ajmaline prolonged the action potential duration in a dose dependent manner. The inhibitory actions of ajmaline on the action potential upstroke and various currents responsible for the plateau and repolarization may contribute to the observed suppression of depolarization-induced abnormal automaticities by this agent.

[A case report of the atypical tuberculosis associated with AIDS]

A 49-year-old Japanese male who had been imprisoned for five years then lived with other men complained of fever, constitutional symptoms and a 12 kg weight loss over four-month period. He was referred to us as his gastric washings were positive for acid-fast bacilli (AFB). Chest X-ray showed patchy, infiltrative small shadows primarily in the right upper lung field without hilar adenopathy. Before transfer to our hospital, tuberculosis chemotherapy composed of SM, INH, RFP and PZA was initiated. Over the next three weeks, fever dropped, and the above described abnormal shadows on the chest X-ray improved, leaving small cystic lesions. Although a sputum smear was negative for AFB, M. tuberculosis was isolated from cultured samples and sensitive to all standard anti-tuberculous drugs. AFB were also demonstrated on a touch imprint of biopsied cervical lymph nodes. Sputum samples turned negative one month later both on smear and culture. Moreover, high fever developed and another abnormal shadow indicative of Pneumocystis carinii (PCP) appeared in the left lung field one month after the admission. White plaque was noted in the oral cavity. Dark red nodules were observed on the upper extremities and chest wall, and diagnosed histologically as Kaposi's sarcoma. Serologic testing for HIV was positive both by PA and Western blot methods, thus AIDS was diagnosed according to the CDC surveillance case definition for AIDS with the diagnosis of tuberculosis. The patient died of wasting syndrome on the 90th hospital day. On autopsy, small thin-walled cavities were observed in the right upper lung, correlating with earlier X-ray and CT findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrophysiological effects of SD-3212, a novel antiarrhythmic agent, on rabbit hearts in vivo and in vitro

We examined the electrophysiological effects of SD-3212, a novel antiarrhythmic agent in rabbits in in vivo and in vitro experiments. During in vivo experiments, monophasic action potentials (MAPs) of the left ventricular endocardium were simultaneously recorded with surface ECG and arterial blood pressure (BP). Under constant atrial pacing, SD-3212 (0.1, 0.2, and 0.3 mg/kg/min) was continuously infused in rabbits for 20 min. SD-3212 > or = 0.2 mg/kg/min prolonged PQ interval, QRS duration, and MAP duration, and decreased arterial BP dose dependently. During in vitro experiments, transmembrane APs were recorded from the isolated papillary muscles by a microelectrode technique. SD-3212 (3 x 10(-6)-10(-5) M) prolonged the AP duration (APD) and decreased the maximum upstroke velocity of the AP (Vmax) in a concentration-dependent manner without affecting the amplitude of AP or resting potential. The inhibitory action of SD-3212 on Vmax was enhanced as the stimulation frequency was increased, whereas the prolongation of APD did not vary with stimulation frequency. The results suggest that SD-3212 has an inhibitory action on some outward currents as well as sodium and calcium currents.

OlpB, a new outer layer protein of Clostridium thermocellum, and binding of its S-layer-like domains to components of the cell envelope

Several proteins of Clostridium thermocellum possess a C-terminal triplicated sequence related to bacterial cell surface proteins. This sequence was named the SLH domain (for S-layer homology), and it was proposed that it might serve to anchor proteins to the cell surface (A. Lupas, H. Engelhardt, J. Peters, U. Santarius, S. Volker, and W. Baumeister, J. Bacteriol. 176:1224-1233, 1994). This hypothesis was investigated by using the SLH-containing protein ORF1p from C. thermocellum as a model. Subcellular fractionation, immunoblotting, and electron microscopy of immunocytochemically labeled cells indicated that ORF1p was located on the surface of C. thermocellum. To detect C. thermocellum components interacting with the SLH domains of ORF1p, a probe was constructed by grafting these domains on the C terminus of the MalE protein of Escherichia coli. The SLH domains conferred on the chimeric protein (MalE-ORF1p-C) the ability to bind noncovalently to the peptidoglycan of C. thermocellum. In addition, 125I-labeled MalE-ORF1p-C was shown to bind to SLH-bearing proteins transferred onto nitrocellulose, and to a 26- to 28-kDa component of the cell envelope. These results agree with the hypothesis that SLH domains contribute to the binding of exocellular proteins to the cell surface of bacteria. The gene carrying ORF1 and its product, ORF1p, are renamed olpB and OlpB (for outer layer protein B), respectively.

Evolutionary origins of apoB mRNA editing: catalysis by a cytidine deaminase that has acquired a novel RNA-binding motif at its active site

The site-specific C to U editing of apolipoprotein B100 (apoB100) mRNA requires a 27 kDa protein (p27) with homology to cytidine deaminase. Here, we show that p27 is a zinc-containing deaminase, which operates catalytically like the E. coli enzyme that acts on monomeric substrate. In contrast with the bacterial enzyme that does not bind RNA, p27 interacts with its polymeric apoB mRNA substrate at AU sequences adjacent to the editing site. This interaction is necessary for editing. RNA binding is mediated through amino acid residues involved in zinc coordination, in proton shuttling, and in forming the alpha beta alpha structure that encompasses the active site. However, certain mutations that inactivate the enzyme do not affect RNA binding. Thus, RNA binding does not require a catalytically active site. The acquisition of polymeric substrate binding provides a route for the evolution of this editing enzyme from one that acts on monomeric substrates.

Multiple promoters in rat acyl-CoA synthetase gene mediate differential expression of multiple transcripts with 5'-end heterogeneity

Nucleotide sequence analysis of six independently isolated cDNAs for rat acyl-CoA synthetase (ACS) revealed three forms of ACS mRNA, designated form-A, -B, and -C mRNAs, which differ in their 5'-untranslated regions. Form-A mRNA was preferentially detected in normal and peroxisome-induced livers, whereas form-B mRNA was found in peroxisome-induced livers but not in normal livers and hearts, and form-C mRNA was preferentially found in normal hearts and peroxisome-induced livers. Analysis of two overlapping genomic clones for the rat ACS gene revealed that the three 5'-untranslated regions of the mRNAs are individually encoded by three different exons located within a 20-kilobase genomic fragment. The transcription start sites of the three forms of ACS mRNA were determined and nucleotide sequences of 5'-upstream regions of the three 5'-end exons were determined. The 5'-upstream regions were fused to the chloramphenicol acetyltransferase gene and transcription units of the three forms of ACS mRNAs were determined. These data indicate that the three forms of ACS mRNA with 5'-end heterogeneity are generated by alternative transcription from three promoters in the rat ACS gene.

Effects of diet on the lipid composition of the digestive gland-gonad complex of Biomphalaria glabrata (Gastropoda) infected with larval Echinostoma caproni (Trematoda)

This study examined the effects of a larval Echinostoma caproni infection on the neutral lipid composition of the digestive gland-gonad complex (DGG) of Biomphalaria glabrata snails fed hen's egg yolk supplemented with lettuce (Y-L) or lettuce supplemented with Tetramin (L-T). Snails were experimentally infected with the miracidial stage of this echinostome, and their DGGs containing daughter rediae were analyzed for neutral lipids five weeks post-infection by qualitative and quantitative thin-layer chromatography. Light microscopy using Oil Red O (ORO) staining and transmission electron microscopy (TEM) were used to localize neutral lipids in the rediae. The DGGs of infected snails maintained on the Y-L diet showed a significant increase in free sterols and a significant decrease in triacylglycerols compared to uninfected snails maintained on the Y-L diet. The DGGs of infected snails maintained on the L-T diet showed no significant difference in free sterols or triacylglycerols compared to uninfected snails maintained on the L-T diet. ORO staining and TEM showed the presence of lipid droplets in rediae from snails on the Y-L diet. The significant decrease in triacylglycerols in the DGGs of infected snails maintained on the Y-L diet suggests that triacylglycerols were utilized by the rediae.

Kinetic properties and structural characterization of highly purified acetyl-CoA synthetase from bovine heart and tissue distribution of the enzyme in rat tissues

Acetyl-CoA synthetase from bovine heart has been purified to homogeneity and been crystallized. The purification procedure involves ammonium sulfate precipitation and subsequent column chromatography on DEAE-Sepharose, Blue-Sepharose, CoA-Agarose and Superose 6. The purified enzyme has a specific activity of 45 units/mg protein, and its molecular weight estimated by sodium dodecyl sulfate polyacrylamide gel electrophoresis is approximately 72,000. The purified enzyme specifically utilizes acetate, ATP and CoA. Apparent Km values of the purified enzyme for acetate, CoA, and ATP were 0.16 mM, 0.14 mM and 0.25 mM, respectively. Limited digestion with trypsin, subtilisin BPN' and chymotrypsin revealed that the enzyme contains a 56 k segment resistant to these proteases. Secondary structure contents of the purified enzyme and the 56 k tryptic fragment were analyzed by circular dichroism measurement. The intact molecule contains 30% alpha-helix and 30% beta-structure, and trypsin digests alpha-helix rich regions more substantially. Western blot analysis of rat tissue homogenates by specific antibodies against the purified enzyme indicated that the 72 k enzyme is present in a wide variety of tissues and is most abundant in heart and kidney.

Aflatoxin B1-induced immortalization of cultured skin fibroblasts from a patient with Li-Fraumeni syndrome

To examine the mechanisms of immortalization in human cells, normal human diploid fibroblasts (WHE-7) and skin fibroblasts from a patient with Li-Fraumeni syndrome (MDAH 087) and a mutant p53 allele were treated with aflatoxin B1 (AFB1). Exogenous metabolic activation of AFB1 with rat liver post-mitochondrial supernatant (PMS) was used and the optimal treatment conditions needed were determined by the inducibility of unscheduled DNA synthesis. The same degree of cytotoxicity was observed with MDAH 087 cells and normal WHE-7 cells treated with AFB1 at 0.1, 0.3 or 1 microgram/ml for 2 h with a 2% PMS mixture. All WHE-7 cell cultures (AFB1-treated and controls) failed to escape from senescence, whereas three out of nine AFB1-treated cultures of MDAH 087 cells escaped senescence. MDAH 087 cells treated with 0.1 microgram/ml of AFB1 two or three times initially decreased in growth approximately 40 days [10 population doublings (PD)] after the first treatment. However, the cells recovered with faster growth rates after approximately 100 additional days and grew continuously. Both cultures were immortal, defined as continuous growth for over 300 PD. Cells treated once with 0.3 microgram/ml of AFB1 also escaped senescence, although they had about a 230 day time lag before restoration of cell growth. The three AFB1-treated cell lines exhibited altered morphologies, chromosome aberrations (numerical and structural aberrations) and loss of the wild-type p53 allele. Although immortal, the cells were non-tumorigenic in nude mice. Spontaneous immortalization of untreated MDAH 087 was not observed in this study. The results indicate that AFB1 treatment of cells from a Li-Fraumeni patient, but not cells from normal individuals, can induce immortalization. This model may be useful for studying mechanisms of chemically induced immortalization.

Plasma sulpho-conjugated catecholamine dynamics up to 8 h after 60-min exercise at 50% and 70% maximal oxygen uptakes

The prolonged effects of steady-state exercise and meals on plasma sulpho-conjugated catecholamines (CA) after exercise were examined. Seven male subjects exercised on 2 separate days for 60 min at 50% and 70% of maximal oxygen uptake (VO2max) on a cycle ergometer and then rested, for 8 h sitting in an armchair. A control trial without any exercise was also performed. At 2 h after the end of exercise the subjects were given a meal. The plasma free and sulphated CA, oxygen uptake (VO2) and heart rate (HR) were all measured before exercise, during exercise and hourly during the 8-h recovery period. The sulphated noradrenaline (NA-S) and adrenaline (A-S) concentrations increased after exercise, and, furthermore, only the NA-S concentrations remained elevated for 6 h after exercise at 50% VO2max and for 8 h at 70% VO2max trial, compared with the control trial. There were no changes in either the plasma NA-S or A-S concentrations after consuming a meal, whereas the dopamine sulphate concentration demonstrated a dynamic change. A significantly higher excess postexercise VO2 was observed at 2 h postexercise at 50% VO2max and at 6 h postexercise at 70% VO2max trials. The mean HR was still elevated at 6 and 8 h after exercise, which closely correlated with the duration of the elevated NA-S concentrations. These results suggest that sulphated CA, especially NA-S, could represent an additional index of sympathetic nerve activity after exercise, and that a meal containing small amounts of the amines would seem to have no effect on plasma NA-S and A-S concentrations.

Immortalization-susceptible elements and their binding factors mediate rejuvenation of regulation of the type I collagenase gene in simian virus 40 large T antigen-transformed immortal human fibroblasts

Dramatic changes occur in expression of the type I collagenase gene during the process of immortalization in simian virus 40 large T antigen-transformed human fibroblasts (S. Imai and T. Takano, Biochem. Biophys. Res. Commun. 189:148-153, 1992). From transient transfection assays, it was determined that these changes involved the functions of two immortalization-susceptible cis-acting elements, ISE1 and ISE2, located in a 100-bp region about 1.7 kb upstream. The profiles of binding of an activator, Proserpine, to the enhancer ISE1 were similar in the extracts of young, senescent preimmortalized and immortalized cells. ISE2 contained both negative and positive regulatory elements located adjacent to each other. The positive regulatory element consisted of a tandem array of putative Ets family- and AP-1-binding sites. An activator, Pluto, interacted with this positive regulatory element and had an AP-1-related component as a complex. The binding activity of Pluto was predominantly detected only in the extract from senescent preimmortalized cells. In contrast, a repressor, Orpheus, which bound to the ATG-rich negative regulatory element of ISE2, was prominently detected in extracts from both young preimmortalized and immortalized cells and appeared to suppress transcription in an orientation-dependent manner. Thus, the interplay of Pluto and Orpheus was suggested to be crucial for regulation of the collagenase gene accompanying in vitro aging and immortalization. Proserpine seemed to interact with Pluto to mediate strong expression of the collagenase gene in cellular senescence. On the basis of these results, we propose a model for regulation of the collagenase gene during in vitro aging and immortalization.

Effects of hydrocortisone on transmembrane currents in guinea pig ventricular myocytes--possible evidence for positive inotropism

Steroid hormones are thought to have a positive inotropic action, but the precise electrophysiological effects which underlie this positive inotropism remain unknown. The effects of hydrocortisone on the L-type calcium current (ICa) of the isolated guinea pig ventricular cells were investigated under the whole-cell voltage-clamp recording. Hydrocortisone (10(-6) to 10(-5) M) increased the amplitude of ICa without any changes in the voltage-dependency in ICa. This agent retarded the fast inactivation component of ICa, but not the slow component. On the other hand, hydrocortisone slightly reduced the slope conductance of inward rectifying potassium current (IK1) at potentials less than -50mV. This effect on IK1 is favorable for the activation of ICa. Thus, these results indicate that the positive inotropism of hydrocortisone is mediated, at least in part, by a direct potentiating effect on ICa.

Allelotype of endometrial carcinoma

An allelotype analysis of endometrial carcinoma was undertaken to identify chromosomal loci that are relevant to this tumor type. A total of 70 highly polymorphic microsatellite markers, distributed among all nonacrocentric chromosome arms, were examined for evidence of loss of heterozygosity or allelic imbalance in DNA samples from matched normal and tumor tissues. An average of 21 informative tumor cases were obtained for each marker. Allelic deletions or imbalance were observed on 31 of 41 chromosome arms with no marker showing an allelic loss ratio of greater than 33%. Those chromosome arms most frequently involved were 3p, 8p, 9p, 14q, 16q and 18q. There was a strong correlation between loss of heterozygosity on chromosome 14q and death from disease. These data indicate that the molecular genetic character of endometrial carcinoma is complex and that a relatively large number of different chromosomal loci are likely to play a role in the etiology and progression of this tumor type.

Fuzzy and conventional control of high-frequency ventilation

A high-frequency ventilator was developed, consisting of a single-phase induction motor, an unbalanced mass and a mechanical vibration system. Intermittent positive pressure respiration was combined with high-frequency ventilation to measure end-tidal pCO2. Hysteresis was observed between the rotational frequency of the high-frequency ventilator and end-tidal pCO2. A fuzzy proportional plus integral control system, designed on the basis of the static characteristics of the controlled system and a knowledge of respiratory physiology, successfully regulated end-tidal pCO2. The characteristics of gas exchange under high-frequency ventilation was approximated by a first-order linear model. A conventional PI control system, designed on the basis of the approximated model, regulated end-tidal pCO2 with a performance similar to that of the fuzzy PI control system. The design of the fuzzy control system required less knowledge about the controlled system than that of the conventional control system.