Muscular urinary sphincter: electrically stimulated myoplasty for functional sphincter reconstruction

PURPOSE

To reconstruct an electrically stimulated muscular urinary sphincter (MUS) using a tailored gracilis muscle free flap with intact nerve.

MATERIALS AND METHODS

Unilateral surgically tailored gracilis muscle free flaps were transferred into the pelvis in eight dogs, leaving the obturator nerve intact. The muscle's pedicle vessels were anastomosed to the inferior epigastric artery and vein in the pelvis and the muscle was wrapped around the bladder neck. Electrodes were inserted into the MUS and connected to a programmable pulse generator. After 8 weeks of training the MUS, the pulse generator was programmed to be "on" for 4 hours and "off' for 15 minutes in a continuous cycle. Urodynamic studies were performed periodically, and at the end of the experiment the MUS and proximal urethra were harvested for histology. Three control dogs had sham operations.

RESULTS

All MUS's functioned well following the procedure. Histology of the MUS/urethra complex showed no evidence of stricture. Except for one dog, all urethras were easily catheterized.

CONCLUSIONS

This electrically stimulated innervated free-flap MUS technique effectively increases bladder outlet resistance without producing urethral obstruction.

[Study on nuclear matrix protein in leukemia cells]

OBJECTIVE

To compare the composition of nuclear matrix proteins (NMP) between leukemia cells and normal bone marrow cells.

METHODS

NMP was isolated by high-salt extration and identified by SDS-PAGE and western blotting.

RESULTS

Increase in NMP was demonstrated in acute and chronic myelogenous leukemic cells as well as in the blast phase of chronic leukemia. On SDS-PAGE, NMPs with molecular weight different from what were seen in normal bone marrow cells were present in both acute and chronic myelogenous leukemias.

CONCLUSION

Marked changes of NMP, not only in contents but also in compositions, exist in leukemic cells compared with normal bone marrow cells. NMP may serve as a target of chemotherapeutic drugs against leukemia.

[Isolation and identification of active constituent of Toddalia asiatica in cardiovascular system]

The ethereal extract from the crude ethanolic extract of Toddalia asiatica was chromatographed on silica gel and tested on biological activity. A crystalline was obtained and confirmed as an active constituent in cardiovascular system. The active constituent was identified as isopimpinellin on the basis of chemical method and spectral analysis.

Glycophorin variants and contents of sialic acid and total sulfhydryl groups on erythrocyte membranes of residents in a malaria hyperendemic area

OBJECTIVE

To conduct a screening survey of glycophorin (GP) variants and observe the content changes of sialic acid (SA) and total sulfhydryl (SH) groups on the erythrocyte membranes among residents in a tertian malaria hyperendemic area of Guizhou Province.

METHODS

GP variants were detected in the erythrocyte hemolysates of 173 local residents at two villages of Libo County by SDS-PAGE on 10% to 15% gradients gel and Western immunoblotting. Their SA and total SH group contents were estimated in erythrocyte membranes by spectrophotometric methods. 114 healthy subjects in Changsha and 49 individuals at a neighbouring village of the above area showing low morbidity of malaria served as normal and endemic controls respectively.

RESULTS

Three distinct types of GP variants were found among 19 propositi in this hyperendemic area. The incidence of GP variants was 7.9% (8/101) at Yaolu Village whose population was mainly composed of Yao ethnic group; while that of Buyi ethnic group at Maolan Village was higher (15.3%; 11/72). The erythrocyte membrane contents of SA in residents at both villages exhibited a very significant tendency of decline (P < 0.01), whereas those of total SH groups increased prominently in residents of Yaolu Village only (P < 0.05).

CONCLUSIONS

The frequency of GP variants in this hyperendemic area does not depend upon the severity of malarial prevalence. The evident reduction of SA contents in the residents may be related to the breaking down of the SA residues on membrane GPs by the invasion of Plasmodium vivax.

Male sterility and meiotic drive associated with sex chromosome rearrangements in Drosophila. Role of X-Y pairing

In Drosophila melanogaster, deletions of the pericentromeric X heterochromatin cause X-Y nondisjunction, reduced male fertility and distorted sperm recovery ratios (meiotic drive) in combination with a normal Y chromosome and interact with Y-autosome translocations (T(Y;A)) to cause complete male sterility. The pericentromeric heterochromatin has been shown to contain the male-specific X-Y meiotic pairing sites, which consist mostly of a 240-bp repeated sequence in the intergenic spacers (IGS) of the rDNA repeats. The experiments in this paper address the relationship between X-Y pairing failure and the meiotic drive and sterility effects of Xh deletions. X-linked insertions either of complete rDNA repeats or of rDNA fragments that contain the IGS were found to suppress X-Y nondisjunction and meiotic drive in Xh-/Y males, and to restore fertility to Xh-/T(Y;A) males for eight of nine tested Y-autosome translocations. rDNA fragments devoid of IGS repeats proved incapable of suppressing either meiotic drive or chromosomal sterility. These results indicate that the various spermatogenic disruptions associated with X heterochromatic deletions are all consequences of X-Y pairing failure. We interpret these findings in terms of a novel model in which misalignment of chromosomes triggers a checkpoint that acts by disabling the spermatids that derive from affected spermatocytes.

[A study on apoptotic cell death during chemotherapy of patients with acute leukemia]

OBJECTIVE

To investigate whether apoptosis occurs in vivo in patients with acute leukemia during induction chemotherapy and its significance.

METHODS

Apoptotic effect on peripheral blood of 20 patients with different types of acute leukemia prior to and during routine chemotherapy was studied by cell morphology, DNA electrophoresis and FCM-DNA analysis.

RESULTS

After chemotherapy, with falls in WBC and blast count, no apoptotic cell appeared on smears of peripheral blood, nor did ladder pattern of DNA on electrophoresis and subdiploid peak on FCM.

CONCLUSION

Although anticancer drugs have been shown to induce apoptosis in vitro, circulating apoptotic cells are hardly detected probably due to their rapid clearance from the circulation. It is more difficult to study apoptosis in vivo than in vitro.

Identification of specific mRNAs affected by treatments producing long-term facilitation in Aplysia

Neural correlates of long-term sensitization of defensive withdrawal reflexes in Aplysia occur in sensory neurons in the pleural ganglia and can be mimicked by exposure of these neurons to serotonin (5-HT). Studies using inhibitors indicate that transcription is necessary for production of long-term facilitation by 5-HT. Several mRNAs that change in response to 5-HT have been identified, but the molecular events responsible for long-term facilitation have not yet been fully described. To detect additional changes in mRNAs, we investigated the effects of 5-HT (1.5 hr) on levels of mRNA in pleural-pedal ganglia using in vitro translation. Four mRNAs were affected by 5-HT, three of which were identified as calmodulin (CaM), phosphoglycerate kinase (PGK), and a novel gene product (protein 3). Using RNase protection assays, we found that 5-HT increased all three mRNAs in the pleural sensory neurons. CaM and protein 3 mRNAs were also increased in the sensory neurons by sensitization training. Furthermore, stimulation of peripheral nerves of pleural-pedal ganglia, an in vitro analog of sensitization training, increased the incorporation of labeled amino acids into CaM, PGK, and protein 3. These results indicate that increases in CaM, PGK, and protein 3 are part of the early response of sensory neurons to stimuli that produce long-term facilitation, and that CaM and protein 3 could have a role in the generation of long-term sensitization.

[Effects of exposure to noise in oil-drilling well sites on cochlea in guinea pigs]

OBJECTIVE

To prevent from hearing damage caused by noise in the sites with drilling wells.

METHODS

Intensity and spectrum of the noise produced in the sites with drilling wells were measured and analyzed. Measures, such as sound insulation, vibration damping and changing layouts of the drilling platform, were adopted, and electrocochleography (ECochG) and scanning electron microscopy were used to observe the effects of noise in the sites where drilling wells located on the hearing organs in guinea pigs after exposure.

RESULTS

There was no significant difference in APN1 latency of ECochG before and after exposure to noise. There were significant difference in hearing threshold values between the groups in a room with sound isolation, in moving status and beside the diesel engine, and no significant difference in those between the groups placed one meter horizontally and vertically away from the diesel engine on the drilling platform. Damage to hairy cell under scanning electron microscope was more severe in the guinea pigs placed beside the diesel engine and at the drilling well platform, with inclination and exfoliation of static pili of outer hairy cells, especially in the second and third lines, and part exfoliation of inner hairy cell. Hairy cells of the guinea pigs in a room with sound insulation and in moving status were basically normal. Inclination of hairy cells only could be seen in the third line.

CONCLUSION

Animal experiments indicated that the measures mentioned above are effective and should be applied widely for preventing from hearing damage.

[The analysis of donkey-hide glue, antler glue and tortoise shell glue by means of circular dichroism]

Donkey-hide glue, antler glue, tortoise shell glue and their forgeries were identified by the analysis method of circular dichroism(CD) in this paper. The standard spectra and data were set up. The method is simple, fast and accurate.

[The effect of GM-CSF on endothelin-1 and endothelin converting enzyme gene expression in human airway smooth muscle cells with or without theophylline incubation]

OBJECTIVE

To explore the role of airway smooth muscle cells (ASMC) stimulated by inflammatory factors in the development of asthma and bronchial hyperresponsiveness (BHR) and the possible mechanism of low dose theophylline in the treatment of airway inflammation, the effects of GM-CSF on endothelin-1 and endothelin converting enzyme (ECE) gene expression in human ASMC and theophylline on their expressions were investigated.

METHOD

The cultured human ASMCs were treated with GM-CSF (1,000 micrograms/ml), GM-CSF plus theophylline (125 ng/ml) respectively for 8 hours. Endothelin-1 and ECE gene expresion were measured by RT-PCR.

RESULT

There was no ET-1 gene expression in control group, but strong expression in GM-CSF treated group; theophylline entirely inhibited GM-CSF induced ET-1 gene expression in the ASMC; no significant difference of ECE gene expression was found in three groups.

CONCLUSION

GM-CSF causes a strong ET-1 gene expression but not ECE gene expression in cultured human airway smooth muscle cells; theophyllin inhibites this abnormal expression which may be one of the anti-inflammatory mechanisms of low dose theophylline in the management of chronic airway inflammation.

[Photoluminescence and UV-Vis absorption spectra characteristics of metal complexes of 8-hydroxyquinoline]

8-hydroxyquinoline complexes of Na(I), Ca(II), Mg(II), Zn(II), Cu(II), Mn(II), Al(III), In(III) and La(III) were synthesized. Photoluminescence (PL) and UV-Vis absorption spectra characteristics of these complexes and 8-hydroxyquinoline are reported. Except complexes of Cu and Mn, most of these complexes reveal photoluminescence. With the polarization force of metal cations increasing, the PL peak shows red-shift and two broad absorption peak in UV-Vis (300-400nm) absorption spectra distinctly appears apart.

The biomechanical effect and clinical application of a Ni-Ti shape memory expansion clamp

STUDY DESIGN

The study involves three phases: a clinical study of 30 patients, a biomechanical study to assess the expansion force of a recovering-shape memory expansion clamp, and a biomechanical study using cadaveric specimens to assess the pullout strength of the shape memory expansion clamp as a function of the shape of the clamp.

OBJECTIVE

To evaluate the biomechanical effect and clinical application of the shape memory expansion clamp.

SUMMARY OF BACKGROUND DATA

The major complication of anterior cervical decompression and fusion was graft dislodgement and pseudarthrosis. Improvement of the shape of bone graft and fusion technique could not eliminate the problem completely. The authors designed the shape memory expansion clamp by using the characteristic of Ni-Ti shape memory alloy and first applied it in an anterior cervical operation.

METHODS

The expansion force of recovering of the shape memory expansion clamp was measured in a biomechanical study. Eight fresh human cadaver cervical spine specimens were used to assess the pullout strength of the shape memory expansion clamp as a function of the shape of the clamp. The shape memory expansion clamp had been used to fix rotated circular grafts in 30 cases with cervical spine injuries or cervical spondylosis after anterior decompression.

RESULTS

The expansion force of the shape memory expansion clamp in recovery was 4.65-27.96 N, and the pullout strength was 8.82-20.58 N. Bone fusion was achieved in all 30 cases. Dislocation of bone graft, loosening of clamp, or kyphotic deformity had not occurred.

CONCLUSION

The expansion force and the pullout strength of the partially recovered shape memory expansion clamp were determined biomechanically. The clinical study demonstrated that the shape memory expansion clamp is safe and effective.

Roles of rDNA spacer and transcription unit-sequences in X-Y meiotic chromosome pairing in Drosophila melanogaster males

Meiotic pairing of the X and Y chromosomes in Drosophila melanogaster males is mediated by the rDNA repeats, which are present in two tandem clusters, one in the centric X heterochromatin and the other near the base of the short arm of the Y chromosome. Deletion of the X chromosomal rDNA cluster disrupts X-Y pairing and causes high frequences of X-Y nondisjunction. Pairing can be partly restored by insertions of cloned complete rRNA genes or by rDNA fragments that include the intergenic spacer (IGS) region. A 240 bp repeated sequence in the IGS was shown to be effective in promoting pairing when present at copy numbers above five. This study further defines the rDNA sequences involved in mediating pairing. Germline insertions of a P element construct containing most of the rDNA transcription unit but no promoter or IGS region were obtained. Two single-copy insertions and four two-copy insertions proved unable to stimulate X-Y disjunction when located on an rDNA-deficient X chromosome. In addition, three insertions of a P element construct consisting of the IGS and promoter regions of the rDNA were characterized molecularly. These three insertions had previously been shown to range in pairing ability from very weak to quite strong. Molecular analysis revealed that the three insertions also vary in copy number of the 240 bp IGS repeat and that these structural differences correlate with the differences in pairing ability. These data indicate that 240 bp repeats are considerably more effective than other regions of the rDNA in stimulating chromosome pairing.

[The mutiplication of Sindbis virus and host BHK-21 cell apoptosis]

The process of apoptosis of BHK-21 cells induced by Sindbis virus (SbV) infection is reported here in details. The nuclear DNA cleavage can be first detected at 6 h after SbV infection, followed by the chromatin margination and condensation at 12 h and the DNA ladder can be detected at 24 h after infection. The details of apoptosis body's formation can be revealed by electron microscopy: First, the outer nuclear membrane protrudes where the condensed chromatin accumulates, then the chromatin get into the budding area with the inner nuclear membrane and separate from the nuclear. Progressively, we cloned the gene of SbV nonstructure protein 2 (nsP2) into the eukaryotic expression vector pMAMneo, and it can be expressed transiently. The DNA cleavages, the basic characteristics of apoptosis also can be detected in some cells. Together with the sequence analysis of nsP2 and the other former results, we conclude that the nsP2 may have direct relation with the SbV-induced apoptosis.

[FT-IR study of Ce3+-doped calcium phthalate phosphor]

FT-IR of the CaC8H4O4 : Ce phosphor prepared by the solution reaction method were determined. Bands of their spectra were assigned. Some structure information about these compounds were given.

[Identification of G6PD gene mutations in several nationalities from Yunnan province]

OBJECTIVE

To analyze the G6PD gene mutations in several nationalities from Yunnan province.

METHODS

G6PD gene mutation of 29 samples from G6PD deficient patients were analyzed by using common and mis-matched primering PCR followed by restriction enzyme digestion. The samples were collected from Yunnan province among several nationalities.

RESULTS

In these 29 cases, 20 were of two known mutations, including 19 of 1388 (G-->A) and 1 of 1376 (G-->T) mutation. The 7 cases of national minorities, including 3 of Yi ([symbol: see text]), 2 of Bai ([symbol: see text]), 1 of Dai ([symbol: see text]), and 1 of Naxi ([symbol: see text]), were all 1388 mutations. No report of the G6PD gene 1388 mutation in these ethnic groups was published excepting for Dai.

CONCLUSION

The mutation probably had been prevalent before the emergence of these national minorities. The approximate rate of G6PD gene mutations provided in Yunnan province may, in some respects, help to interpret the molecular evolution.

[Study on the orientation of PET three-dimensional crimp hollow fiber by IR-ATR]

The variations of structure and orientation of poly (ethylene terephthalate) (PET) three-dimensional crimp hollow fiber were investigated by infrared attenuated total reflection (IR-ATR) method. It was found that the carbonyl group of this PET hollow fiber orientates vertically to the fiber surface.

Mutations in the Cacnl1a4 calcium channel gene are associated with seizures, cerebellar degeneration, and ataxia in tottering and leaner mutant mice

Tottering and leaner, two mutations of the mouse tottering locus, have been studied extensively as models for human epilepsy. Here we describe the isolation, mapping, and expression analysis of Cacnl1a4, a gene encoding the alpha subunit of a proposed P-type calcium channel, and also report the physical mapping and expression patterns of the orthologous human gene. DNA sequencing and gene expression data demonstrate that Cacnl1a4 mutations are the primary cause of seizures and ataxia in tottering and leaner mutant mice, and suggest that tottering locus mutations and human diseases, episodic ataxia 2 and familial hemiplegic migraine, represent mutations in mouse and human versions of the same channel-encoding gene.

Role of intracardiac angiotensin II in cardiac dysfunction of rat during septic shock

OBJECTIVE

To observe changes in the content of myocardial angiotensin II and its role in cardiac dysfunction of rat during septic shock.

METHODS

Septic shock model was produced by cecal ligation and puncture (CLP) operation on rats. Experimental rats were given captopril 15 mg.kg-1/d per os for 3 days before CLP operation. Mean blood pressure and left ventricular pressure were recorded. Myocardial angiotensin converting enzyme (ACE) activities were determined by a fluorometric assay and myocardial angiotensin II content was measured by radioimmunoassay. Highly purified membrane of sarcoplasmic reticulum (SR) was prepared from rat hearts. Assays were made of ATP-dependent Ca2+ uptake by cardiac SR and (3H) ryanodine binding to SR.

RESULTS

Myocardial angiotensin II content increased by 51.5% (P < 0.01) at the 18th hour post CLP, meanwhile there was a decrease in left ventricular +/- dp/dtmax value and the impairment in Ca2+ uptake and (3H) ryanodine binding to cardiac SR. Preliminary administration of captopril reduced myocardial ACE activity and angiotensin II content, but increased left ventricular +/- dp/dtmax value. In comparison to shock group, the initial rate and the capacity of SR Ca2+ uptake were increased by 120% (P < 0.01) and 33.9% (P < 0.05), the Bmax value of (3H) ryanodine binding to SR was also elevated, while the Kd value remained unchanged.

CONCLUSIONS

The elevated intracardiac angiotensin II, resulting from the activation of myocardial ACE during sepsis, probably serves as one of the important mediators participating in the pathogenesis of heart failure: the effects of angiotensin II may be associated with the disturbance of Ca2+ transport function of cardiac SR.

Chronic lead exposure alters transthyretin concentration in rat cerebrospinal fluid: the role of the choroid plexus

The choroid plexus, which is responsible for the maintenance of the biochemical milieu of the cerebrospinal fluid (CSF), avidly sequesters Pb. In order to test the hypothesis that chronic Pb exposure may impair choroid plexus function, male weanling Sprague-Dawley rats were exposed to Pb in drinking water at doses of 0, 50, or 250 micrograms Pb/ml (as Pb acetate) for 30, 60, or 90 days. The function of the choroid plexus was assessed as reflected by CSF concentrations of transthyretin (TTR, a major CSF protein manufactured by brain choroid plexus) and CSF essential metal ions (Ca2+, Mg2+, K+, and Na+). TTR concentrations were determined by radioimmunoassay using a monospecific rabbit anti-rat TTR polyclonal antibody, and CSF metal ions analyzed by flame atomic absorption spectrophotometry. Two-way ANOVA of CSF TTR concentrations revealed highly significant dose (p < 0.0001), time (p < 0.0223), and dose-by-time effects (p < 0.0379). Moreover, the percentage of reduction of CSF TTR was directly correlated with Pb concentrations in the choroid plexus (r = 0.703, p < 0.05). Pb exposure significantly increased CSF concentrations of Mg2+, but did not markedly altered CSF concentrations of Ca2+, K+, and Na+. Histopathologic examination under the light microscope did not show distinct alterations of plexus structure in Pb-treated rats. Since TTR is responsible for transport of thyroid hormones to the developing brain, we postulate that the depression of choroid plexus TTR production (and/or secretion) by Pb may impair brain development in young animals by depriving the CNS of thyroid hormones.

[A study of the relevant factors of removal of common bile duct stones with endoscopic mechanical lithotripsy]

Endoscopic mechanical lithotripsy (EML) was attempted in 41 patients with common bile duct stones unable to be removed by endoscopic sphincterotomy. These patients had altogether 89 stones with stone size ranged from 5 to 30 mm (mean transverse diameter 16.6 +/- 6.0 mm and mean longitudinal diameter 20.0 +/- 7.1 mm). 31 patients had 34 stones greater than or equal to 20 mm in transverse diameter. The overall stone removal rate was 97.6%. The rate of complete removal of the stone fragments with EML at one time was 78.6% (11/14) for large, 58.8% (10/17) for middle and 0 (0/5) for small incision of the sphincter. In patients with diameter of the distal common bile duct greater than or equal to 14 mm and less than 9 mm the rate was 83.3% and 30.8% respectively and the difference was of significance (P < 0.05). The rate of complete removal for using basket and balloon catheter was 6/10 and 4/9 separately and that for combined used of these two methods 83.3% (10/12). The rate of spontaneous passage of the stone (within one week) was 1/5. It is concluded that complete removal of the stone fragments was related mainly to the length of the incision, diameter of distal common bile duct and methods of removing stone fragments after the crush with lithotripsy basket; when the stone is large and there is the no space around the stone for lithotripsy basket manipulation, a large amount of diluted contrast material is injected into the bile duct so as to increase the space and facilitate the ensonaring of the stone with lithotripsy basket. Hard stones can not be crushed easily, so they constitute one of the reasons of failure.

A recA-like gene in Drosophila melanogaster that is expressed at high levels in female but not male meiotic tissues

The RecA protein is the central enzyme in prokaryotic recombination. It catalyzes pairing and strand exchange between homologous DNA molecules, and functions in both DNA repair and genetic recombination. The RecA-like proteins Rad51 and Dmc1 of yeast are both required for meiotic recombination and the former is also necessary for repair of double-strand breaks in vegetative cells. Genes encoding Rad51 homologs have been isolated recently from several higher eukaryotes. This paper describes the isolation and molecular characterization of a genomic DNA fragment from Drosophila melanogaster containing the coding sequence for a RecA-like protein. This protein exhibits strong sequence homology with the Rad51 proteins of budding yeast, fission yeast, chickens, mouse and humans, and slightly less (but still strong) homology with yeast Dmc1. Both in situ hybridization and Southern analysis indicate that the Rad51 gene is present only once per genome in Drosophila (at 99D on chromosome arm 3R). However, there are at least three other fragments that cross-hybridize strongly at low stringency. RNA blotting analysis detects a single transcript of about 1.35 kb that is present throughout development at low levels. Transcript levels are induced at least tenfold in ovaries, as measured by RNase protection analysis, suggestive of a role in female meiosis. Transcript levels are significantly lower in testes than in bulk RNA of adult males, however, indicating that Rad51 may be repressed in meiosis of Drosophila males.

[The disturbance of calcium homeostasis in vascular smooth muscle proliferation after balloon denudation]

OBJECTIVE

To investigate the changes of calcium homeostasis in smooth muscle cells (VSMC) and the role of disturbance of calcium homeostasis in VSMC proliferation after balloon denudation.

METHODS

Assay of the cellular incorporation of 3H-leucine and measurement of 45Ca transport were done on the model of balloon-denuded aorta in rat.

RESULTS

Endothelial injury induced VSMC proliferation, intimal thickening. After balloon denudation, VSMC calcium influx increased (3 days after balloon denudation, 3.28 +/- 0.14 vs 4.12 +/- 0.28, P < 0.05; 10 days 3.31 +/- 0.09 vs 4.09 +/- 0.21 nmol/10(6) cells, P < 0.01), and calcium efflux decreased, and calcium content increased (3 days after balloon denudation 695 +/- 33 vs 995 +/- 54, P < 0.01; 10 days 709 +/- 32 vs 1022 +/- 94 nmol/10(6) cell, P < 0.01). SR and mitochondria calcium uptake increased. Calcium antagonist, verapamil not only regulated the disturbance of calcium homeostasis, but also inhibited endothelium injury-induced VSMC proliferation.

CONCLUSION

The disturbance of calcium homeostasis is probably one of the underlying mechanisms of VSMC proliferation induced by balloon denudation.

Assessment of acute pulmonary edema in dogs by electrical impedance imaging

Acute pulmonary edema was assessed quantitatively in 12 experiments on six anesthetized dogs. Thirty-two copper foil electrodes were placed around each animal's thorax at the level of the third intercostal space. A real-time electrical impedance tomograph was used to form images of the electrical admittivity of the thorax in and near the plane of these electrodes. The lungs were identified by studying the change in admittivity associated with inspiration. Mean admittivity in these lung regions was assessed at 40-min intervals for the next 3-6 hours. In six control experiments, each having a duration of 200 min, the initial admittivity of the lung regions was 102 +/- 16(SD) mS/m. Lung admittivity usually increased during the first 80 min, and then remained within 2 mS/m of its value at 80 min for the remaining 120 min. In six experiments with pulmonary edema, an initial period of change followed by stability was observed. When stability had been attained, 0.07 ml/kg of oleic acid was injected slowly into a central venous site. Five animals received oleic acid, the sixth received a sham injection of saline. In the five receiving oleic acid, lung admittivity rose steadily for the remainder of the experiment. The increase in lung admittivity in these five animals was between 4 and 16 mS/m. In the sham injected experiment, the lung admittivity changed by 1 mS/m. We conclude that impedance imaging can provide semiquantitative assessment of the development of acute pulmonary edema.