[A case of colon cancer associated with schistosomiasis japonica]

A case of colon cancer associated with schistosomiasis japonica is reported. A 60-year-old man was admitted with the complaint of melena. Barium enema study revealed a colon tumor (type 1') 11 cm from the anal ring. Sigmoidectomy was performed, and no lymph node metastasis was observed. Histologically, the tumor was diagnosed as well-differentiated adenocarcinoma, and also many schistosoma ova were found not only in the lesion of the carcinoma, but also in the tissue surrounding the carcinoma. In the latter lesion, ova were observed beneath muscularis mucosae. The distributions of the ova in the anal side of the tumor were more dominant than those in oral side. We review the direct correlation between gastrointestinal tract cancer and the schistosomiasis japonica in other reports.

Differences in drug delivery with peripheral and central venous injections: normal perfusion

The differences between central venous (CV) and peripheral venous (PV) injections with respect to drug delivery times and peak concentrations in the left ventricle are examined. In this drug-delivery model, anesthetized dogs (n = 7) received both PV and CV injections of a radionuclide tracer. Measurements of radioactivity levels were made over each ventricle during normal perfusion. There was no statistically significant difference in left ventricular delivery times or peak radioactivity levels between the two different routes. When delivery time was corrected for variations in flow rate, a small but statistically significant difference was seen, the CV route being faster than the PV route (P less than 0.05). The magnitude of the observed difference for normal perfusion (2 seconds) is unlikely to be of clinical significance.

Biochemical and immunological study of lumbar disc degeneration

Proteoglycans of 18 lumbar discs obtained at surgery for lumbar disc lesion were studied biochemically and immunologically (using monoclonal antibody that recognizes core protein of annulus fibrosus proteoglycans) and compared with the results of similar studies on discs obtained at autopsy and Zielke's operation for scoliosis. Disc proteoglycans showed a decrease in extraction and hexuronic acid/protein weight ratio with age in both surgical and post-mortem specimens. Although the molecular weight of proteoglycan monomer seemed to show a slight decrease, that of chondroitin sulfate chain showed no change with age in surgical discs. The proportion of proteoglycan aggregate showed a decrease with age until 40 years old, it went up thereafter because of the loss of proteoglycan monomers. This biochemical degeneration paralleled discogramic degeneration and monoclonal antibody that recognized core protein showed a strong affinity with severely degenerated discs. Besides aging, lumbar instability seemed to exert a profound influence on the progression of degeneration.

Lung cancer in chromate workers--analysis of 11 cases

We have experienced 11 cases of lung carcinoma in workers at a chromate factory during the past 14 years. All patients were males. The age of onset ranged from 41 to 68 years. Ten of the 11 were heavy smokers. The time of exposure to chromate was from 17 to 29 years and the average was 23.9 years. Seven patients had perforation of their nasal septa. The primary sites of the cancers were from the lobar to the subsegmental bronchi. There were nine squamous cell carcinomas and three small cell carcinomas. Four squamous cell carcinomas were hilar type early stage cancers and two of them were found in one patient at the same time. The chromium content of the lung tissue in the seven patients tested was from 13.9 to 2,368.4 micrograms/g of dry tissue and was higher than that of lung cancer or non-lung cancer cases without chromate exposure. There was no severe dysplasia of the bronchial epithelium in these 11 patients.

The mechanism of the ejection of a frothy fluid from the cloaca in the male turkey

The mechanism of the ejection of a frothy fluid from the "tissue at the vicinity of the papilla" (TVP) of the ductus deferens and triangular fold (TF) of the cloaca of the male turkey during natural copulation was investigated. Injection of Evans blue (T-1824) solution into the wing vein of the intact male led to the ejection, immediately after injection, of frothy fluid colored blue. Ligation of the A. pudenda interna decreased the volume of fluid to a negligible amount, and removal of the paracloacal vascular body (Corpus vasculare paracloacale) completely suppressed the tumescence of the copulatory organ and the flow of the fluid (lymph-like fluid). Evans blue solution, introduced into the A. pudenda interna of dissected cloacal specimens, exuded out from the TVP but not from the lymphatic folds (plicae lymphaticae). Injection of dye solution into the paracloacal vascular body elicited only the erection of the phallus, and none flowed out from the surface of the lymphatic folds. Also, no ejection of the injected dye solution into the A. pudenda interna was found in the dorsal wall of the cloaca, particularly from the TF. The results suggest that lymph generated in the paracloacal vascular body caused only the tumescence of the copulatory organ and a lymph generated in the TVP exuded through the surface epithelium. In addition, a foam (froth) is produced in the TF of the middorsal proctodeum during mounting behavior which appears to be added to the aforementioned lymph from the TVP at copulation.

[Two cases of early squamous cell carcinoma of the hilar region of the lung cured by bronchofiberscopic excision]

We experienced two patients with early squamous cell carcinoma at the hilar region of the lung. The carcinoma were completely eliminated by tumor biopsy using a bronchofiberscope. In both cases, there was either pulmonary tuberculosis or a second primary lung cancer (bronchiolo-alveolar carcinoma) on the contralateral side. After bronchoscopic excision of the tumor, the patients were closely observed using by repeat bronchoscopy at 5 to 6 week intervals. One patient is free of recurrence at 4.5 years after treatment and is deemed to be cured. The other patient died of recurrence and metastasis from a second primary bronchioloalveolar carcinoma at 1 year and 5 months after treatment, however he had no recurrence of the squamous cell carcinoma.

Accidental Cs-137 contamination

Widespread use of radionuclides in medicine and industry poses the possibility of radiation accidents. We describe such an occurrence involving three industrial workers. The accident resulted from careless handling of a Cs-137 source. Evaluation of the Cs-137 whole body burden was carried out using stationary and scanning whole body counters. In addition, regional and whole body activity from contamination was assessed using an uncollimated gamma camera. This report emphasizes the value of the gamma camera for detection of radionuclide contamination in radiation accidents.

Early hilar-type squamous cell carcinoma of the lung resected by bronchofiberscopy surviving 5 years

We record a case of early squamous cell carcinoma located in the hilar region of the lung, which was completely resected by multiple tumor biopsies through the bronchofiberscope. In this case, there was concomitant contralateral pulmonary tuberculosis which was treated by right upper lobe lobectomy. The patient had a long history of smoking and had worked for 27 years in a factory that used chromate. Bronchoscopically, there were no abnormal findings in the visible branches of the right bronchial tree, but an early stage squamous cell carcinoma lesion was found at the bifurcation of left B8 and B9+10 bronchi. After bronchofiberscopic excision of the tumor, the patient was closely followed-up by repeated bronchoscopy at intervals of 4 weeks to 6 months. The patient is currently free of recurrence 5 years and 3 months following the initial bronchoscopic excision and is judged to have been cured.

Central versus peripheral intravenous routes in cardiopulmonary resuscitation

The central venous (CV) and peripheral venous (PV) routes of drug administration are generally considered to be equally effective during cardiopulmonary resuscitation (CPR). This canine study compared simulated drug delivery via CV and PV routes during CPR. The CV group dogs had a CV catheter placed via the external jugular vein, and the PV group dogs had a PV catheter placed in the distal forelimb. Thirty seconds after the induction of cardiac arrest with KCl, CPR was begun with a gas-powered chest compressor with ventilations after every fifth compression. Sixty seconds later, a 0.5 ml bolus of technetium 99m-labeled serum albumin was given. Time activity curves were obtained over the right and left ventricles. The mean time for the counts to rise to half the left ventricular peak (T1/2LV) was significantly less for the CV group than for the PV group (P less than 0.05), averaging 11 and 84 seconds, respectively. The time to left ventricular peak (TLV) was also statistically shorter for the CV group than the PV group, averaging 118 versus 258 seconds, respectively. This study demonstrates that central venous administration is more rapid than peripheral venous administration during CPR and supports the preferential use of the central venous route for drug administration clinically.

Plantar fascitis--early blood pool images in diagnosis of inflammatory process

Bone scintigraphy is of diagnostic value in stress fractures where radiography may not be helpful. Obtaining early blood pool images during scintigraphy for suspected stress fractures may help to identify soft tissue inflammation (plantar fascitis) when delayed images are normal.

[Experience with psychotropic agents Pyrethia and Contomin in the terminal care of lung cancer patients]

Among patients with lung cancer, those having PS 4 ( Performance Status 4) and cancer pain received " Pyrecon ", a psychotropic agent, consisting of promethazine hydrochloride ( Pyrethia ) and chlorpromazine hydrochloride ( Contomin ). A mixture of 125 mg of Pyrethia and 50 mg of Contomin was diluted in 500 ml of regular IV solution and given through the central vein at a rate of 20 ml/hr. Pyrecon was found to be effective in patients with severe cancer pain in whom Brompton cocktail was ineffective. Pyrecon was also effective in patients whose daily life rhythm was unsteady due to insomnia caused by anxiety or unrest. We suggest that Pyrecon is effective in the treatment of cancer pain.

Addition to semen of a fluid derived from the cloacal region by male turkeys

This study was performed to clarify whether the semen from the vas deferens (receptacle) is diluted with a fluid at the moment of ejaculation in the male turkey. Semen from the receptacle and vas deferens, ejaculated semen, and the fluid ejected from the cloacal region were obtained and their characteristics were examined. The mean concentration of ejaculated semen was 7.43 X 10(6)/mm3 and that of the receptacle semen was 9.41 X 10(6)/mm3; the former has a positive aldose color reaction in contrast to a completely negative reaction in the latter, suggesting that the receptacle semen might be diluted with fluid containing aldose at ejaculation. The aldose-positive fluid was found to be produced in the cloacal region and could also be collected from vasectomized male turkeys. Thus, ejaculated turkey semen is considered to be a mixture of semen emitted from the receptacle and fluid ejected from cloacal region. The pH value, glucose content, relative viscosity, and electrophoretic mobility of protein of the ejecting fluid were similar to that of blood plasma, suggesting that the fluid might be originating from blood plasma.

Defective bactericidal activity and absence of specific granules in neutrophils from a patient with recurrent bacterial infections

Recent studies have suggested that specific granules and/or their contents may have a role in neutrophil adherence, oxidative metabolism, and other aspects of cell function. In the current report, we studied neutrophil function in a 13-year-old female with recurrent pyogenic infections and absent specific granules previously documented by electron microscopy. Levels of cobalamin (vitamin B12)-binding protein and lactoferrin were markedly decreased in this patient's neutrophils. Bactericidal activity against Escherichia coli was decreased at 60 and 120 min (percentage organisms killed: patient neutrophils, 48 and 33%; control neutrophils, 90 and 99%, respectively). Defective killing of Staphylococcus aureus was also documented. Degranulation and adherence were normal. Levels of lactoferrin and cobalamin-binding protein were decreased in plasma but normal in saliva, indicating that the defect was specific for hematopoietic tissue. Superoxide anion production was normal in the patient, while hydroxyl radical generation was decreased in response to opsonized zymosan. The data support the concept that specific granules and their contents are important for oxidative metabolism and other neutrophil functions.

Low-level internal radionuclide contamination: use of gamma camera for detection

The uncollimated gamma camera was evaluated as a screening tool for the detection of low levels of internal radionuclide contamination. The minimum detectable activity (MDA) is on the order of 1-4 nCi (37-148 Bq) for a 3-min sample and background counting time. Identification of unknown radionuclides at these low levels involves a systematic search and hence requires a more careful peaking method than organ imaging. Most gamma cameras are capable both of detecting a wide range (35 keV to 1.332 MeV) of gamma-ray energies in the presence of three to four radionuclides and also of distinguishing principal gamma-ray energies from Compton scatter. The differences in MDAs among gamma cameras are small, and vary primarily with the background activity. The actual contaminant activities lie between the calculated values based on measurements when the source is 10 cm away from the uncollimated detector head and using point sources both in air and with the tissue-equivalent scatter medium. The widely available gamma camera is capable of screening a large population, either suspected or actually contaminated, in the event of an emergency.

Effects of oviducal cells on the maintenance of motility and fertilizing capacity of fowl spermatozoa stored in a diffusion chamber

Oviducal cells were cultured on the inner or outer side of the membrane filter of a diffusion chamber, and attempts were made to maintain fowl spermatozoa at 41 C in vitro. When spermatozoa were stored along with cultured cells in the diffusion chamber, the high fertilizing capacity was retained for at least 3 days, regardless of whether the spermatozoa stored in the diffusion chamber were in direct contact with the cultured cells. In contrast, spermatozoa stored in the cell-free diffusion chamber or in a test tube showed a relatively low or no fertilizing capacity, respectively.

Myocardial perfusion imaging with 99mTc-DMPE in man

Technetium-99m DMPE (99mTc-DMPE) is a newly synthesized myocardial perfusion imaging agent that shows intense myocardial accumulation in the dog. In the present study, dosimetry and potential clinical usefulness of this agent were assessed in four human subjects. Absorbed radiation doses were low, with the highest doses consisting of 200 mrad/mCi (54 microGy/MBq) to the gallbladder and 160 mrad/mCi (43 microGy/MBq) to the liver. No evidence of clinical toxicity was found. Technetium-99m DMPE did image the myocardium, but the ratio of target to nontarget activity was less favorable than that observed in the dog. Intense hepatic 99mTc-DMPE activity interfered with clinical imaging of the cardiac apex in two of the four subjects. We conclude that the prototype radiopharmaceutical, 99mTc-DMPE, is capable of myocardial perfusion imaging in man but the planar myocardial images produced are of inferior quality compared with 201Tl myocardial images. Further work is justified to develop related compounds to overcome the clinical limitations described.

Possible participation of oviducal movement in spermatozoal transport in domestic fowl

Carbon particles suspended in saline were injected into the vagina, the uterus, or into the magnum, 5 to 10 or 50 to 55 min after an oviposition. Carbon particles injected into the uterus 5 to 10 min postoviposition reached the infundibulum within 5 to 10 min, and particles introduced 50 to 55 min after an oviposition were not transported to the anterior oviduct. When particles were injected intramagnally 50 to 55 min following an oviposition, they moved distally toward the uterus. Particles introduced into the uterus 5 to 10 min after an oxytocin-induced oviposition were transported to the anterior oviduct. Carbon particles deposited into the vagina remained in situ irrespective of the time deposited. These results suggest that a special oviducal movement, which is though to be caused by oviposition, participates in spermatozoal transport through the hen's oviduct.

Secretory function of the ductus deferens of male chickens

Juvenile and castrate male chickens with ligated ductus deferens were treated with androgen to determine which regions of the ductus deferens were involved in fluid secretion and to determine the characteristics (pH and protein content) of the secretions. The ductus deferens developed with androgen injection contained a dilute secretion. No significant differences in pH and protein content of the fluid were observed between juvenile and castrate males. Regional ligation of the ductus deferens showed that fluid secretion occurred throughout the length of the tract.

Evidence of left ventricular aneurysm by thallium-201 myocardial scintigraphy

TI-201 myocardial scintigrams from 100 patients were reviewed for evidence of left ventricular aneurysms without prior knowledge of the clinical or angiographic data. Scintigraphic evidence of left ventricular aneurysms was considered present when TI-201 myocardial activity extended outward from the expected left ventricular contour in a region adjacent to an area of resting scintigraphic hypoperfusion. Scintigraphic findings suggestive of left ventricular aneurysm were detected in four patients, of whom three had angiographic evidence of left ventricular aneurysm. In the fourth patient, a dilated, akinetic left ventricular apex was present but an angiographic diagnosis of left ventricular aneurysm was not made. In three additional patients with angiographic evidence of left ventricular aneurysm, scintigraphic criteria for left ventricular aneurysm were absent. Although ungated TI-201 myocardial scintigraphy is an insensitive technique for the detection of left ventricular aneurysm, a characteristic scintigraphic pattern should suggest that a left ventricular aneurysm is present.

Prolonged survival of fowl spermatozoa in the oviducal tissues in organ culture

1. When fowl spermatozoa were incubated at 41 degrees C with tissues from the infundibulum, magnum, isthmus, shell gland, uterovaginal junction and vagina, their motility, assessed at room temperature (20 to 25 degrees C), was maintained for 4 to 12 d. 2. The survival period was much longer for spermatozoa incubated with the tissues from the infundibulum and uterovaginal junction (with sperm-host glands, 11 to 12 d) than for those incubated with tissues from the other regions (lacking host glands, 4 to 7 d). 3. In the tissues of the infundibulum and uterovaginal junction, spermatozoa entered the sperm-host glands and were more closely associated with the epithelial cells than they were in tissues from other regions.

Prolonged survival of fowl spermatozoa stored in a diffusion chamber in vitro

1. A diffusion chamber technique was used in an attempt to prolong the life-span of fowl spermatozoa at 41 degrees C in vitro. 2. The most suitable conditions in the diffusion chamber system for this purpose were found to be pH 7.2, with the addition of foetal calf serum (400 mg/ml), a sperm concentration of 10 X 10(9)/ml and a gas mixture of 5% CO2 + 5% O2 + 90% N2. 3. The spermatozoa stored in the diffusion chamber under these conditions were highly fertile for at least 2 d, whereas those stored in a test tube had a low fertilizing ability.

Measurements of the distribution of technetium-99m sulfur colloid and technetium-99m HEDP in normal humans

Technetium-99m sulfur colloid and technetium-99m hydroxyethylidene diphosphonate (HEDP) are two radiopharmaceuticals that have been widely used in nuclear medicine. Radiation dose estimates for both materials have been published in the literature and are found in the package inserts of the commercial kits. However, these estimates were made without the benefit of quantitative human organ uptake data. Estimates of absorbed radiation dose to the kidneys differ by nearly a factor of 6 between the two calculations for HEDP. The results of this study are in agreement with the lower previous estimate. Other than that one exception, agreement of the previous estimates with the measurements reported here is surprisingly good.

Thallium-201 imaging artifacts not detected by technetium-99m or cobalt-57 quality-control testing

Early stages of hydration in a sodium iodide crystal may cause artifactual "hot" spots on thallium-201 heart images. This phenomenon was observed when a mobile gamma camera was used even though the daily quality-control flood-field views revealed no apparent abnormalities. Nevertheless, hot spots were visible on thallium-201 and xenon-133 flood-field images. With asymmetric photopeak positioning using a technetium-99m source, hot spots were noted in addition to phototube nonuniformities. Subsequently, the camera head was disassembled, the crystal was inspected visually, and the crystal seal was found to be broken. Hydration of the crystal was confirmed by the camera manufacturer. Quality-control procedures should test for hydration-induced artifacts on a regular basis.

Effect of coronary blood flow on uptake and washout of Tc-99m DMPE and Tl-201

After intravenous administration of Tc-99m DMPE the flow-dependent kinetics were studied in dogs during induced ischemia and during induced maximal reactive hyperemia. A control group was also studied. Mean time-activity curves obtained from the myocardial wall were compared within the same intervention group and also with other groups. During reactive hyperemia, there was a rapid and absolute increase in uptake followed by a rapid washout, whereas during ischemia there was a slow and decreased uptake followed by a slow washout. The magnitude of Tc-99m DMPE uptake during reactive hyperemia was slightly less than that of Tl-201, but the decreased uptake with ischemia was about equal for the two agents. Following maximal uptake in the myocardium the effective half-life of Tc-99m DMPE was one-third to one-fourth that of Tl-201. The similar kinetics of Tc-99m DMPE compared to Tl-201 suggests its usefulness in the evaluation of ischemic heart disease.

Basal kinetic studies of Tc-99m DMPE as a myocardial imaging agent in the dog

Newly synthesized Tc-99m dichlorobis(1,2-dimethylphosphino)ethane (DMPE) was investigated as a myocardial imaging agent with respect to its kinetics (dependent on both time and regional coronary blood flow), its percent organ uptake, and its imaging characteristics in the anesthetized dog. Most of these data are compared with those of Tl-201. Blood clearance of the two agents is essentially the same. Compared with Tl-201, Tc-99m DMPE shows faster overall kinetics, higher heart-to-lung ratio, equally good correlation with a wide range of regional blood flows, and higher liver uptake. At the time of peak myocardial uptake, the mean heart uptake of Tl-201 is 4.3%, compared with 2.9% for Tc-99m DMPE, yet only 0.9% uptake of Tc-99m DMPE is found in the lung as compared with 3.3% for Tl-201. These differences result in a heart-to-lung ratio of 2:1 for Tc-99m DMPE and 1:1 for Tl-201, based on the data obtained from the time-activity curve. The quantitative findings are supported by the superior quality of Tc-99m DMPE images of both normal and infarcted dog heart. The high hepatic uptake of Tc-99m DMPE is not a serious problem if images are obtained within 5-60 min after dose. These basic kinetic studies suggest that Tc-99m DMPE is a promising myocardial imaging agent.

[Studies on phage type, beta-lactamase activity and sensitivity of multiple drug-resistant Staphylococcus aureus isolated from clinical specimens to cefmetazole]

The 868 strains of S. aureus were isolated at the Department of Pediatrics, Third Hospital and Aoto Hospital, The Jikei University, School of Medicine and the Kanagawa Prefectural Nursing and Hygienic School Hospital during 6 months from May to October in 1981. From them 66 strains not sensitive to CEZ were selected by a 3-concentration disk method. A total number of 54 strains except for 12 isolated from the same infant patient was examined for their MIC's for 6 drugs, CMZ, CEZ, CTM, CXM, MCIPC and GM. Moreover, phage typing and beta-lactamase activity determination were carried out in them. 1. Antibacterial activity Sixty-six (7.6) of 868 strains were not sensitive to CEZ. The MIC's of CMZ against these resistant strains were between 1.56 and 50 micrograms/ml with a peak between 3.13 and 6.25 micrograms/ml when the 10(5) cells/ml bacterial suspension were inoculated. CMZ was superior in antibacterial activity to CEZ and CXM by about 4 degrees and to CTM by about 3 degrees. MCIPC and GM has higher antibacterial activity against a few strains than CMZ. However, the number of strains with MIC higher than or equal to 50 micrograms/ml was 17 for MCIPC and 40 for GM, but only 2 for CMZ. Thus, the former 2 drugs were far inferior to the latter one. 2. Phage type (1) Nineteen strains (35.2%) had MIC's for CEZ greater than 50 micrograms/ml and CMZ less than 6.25 micrograms/ml. Seventeen of them belonged to the nontypable. (2) Fourteen (25.9%) had MIC's for CEZ greater than 100 micrograms/ml. Of them 9 were allocated to the group III, 3 to the mixed (I + II + III, I + III) group and 2 to the nontypable. (3) Of 20 strains (37.0%) which had MIC's for CEZ greater than 100 micrograms/ml and CMZ less than 6.25 micrograms/ml 5 belonged to the group I, 3 to the group III and 12 to the nontypable. (4) Five strains classified into the group I were all isolated at the Kanagawa Perfectural Nursing and Hygienic School Hospital. (5) Eleven of 15 strains belonging to the group III were isolated at the Third Hospital, The Jikei University, School of Medicine. (6) Seventeen of 21 strains isolated at the Aoto Hospital, The Jikei University, School of Medicine belonged to the nontypable. (7) Phage type was considered to be influenced by difference in areas, infection within hospitals, etc., 3. beta-Lactamase activity beta-Lactamase activity was demonstrated at levels between 0.07 and 3.26 mumol/min/mg in all 54 strains. There was no correlation between MIC for CEZ or CEZ and beta-lactamase activity. It was suggested that beta-lactamase might not contribute to mechanism of resistance of S. aureus to each drug examined.

Exposure to Xenon 133 in the nuclear medicine laboratory

Exposure of nuclear medicine personnel to 133X was examined quantitatively at three area hospitals during ventilation-perfusion studies in which the technologists breathed through a specially made xenon-trapping apparatus. The accumulated mean xenon activity varied a great deal from hospital to hospital, ranging from 52 nCi (1.92 kBq) to over 5 microCi (185 kBq) during a typical 20-minute lung study. The observed difference largely depended on the xenon exhaust and trapping systems, which could make a 100-fold difference in exposure rates. The air flow and its exchange rate in the room were additional factors contributing to the different exposure rates. Although the patient continued to be a source of xenon contamination throughout the study, the xenon-trapping system, while operational, could exhaust substantial quantities of xenon. The exhaust duct system, on the other hand, left little contaminated air in the room, resulting in the least exposure to personnel.

Effect of coronary blood flow on thallium-201 uptake and washout

Myocardial uptake and washout of thallium-201 (201TI) were studied in an experimental dog model in which regional blood flow to the posterior wall was varied by transient 2-minute occlusion of the circumflex coronary artery to produce transient ischemia and reactive hyperemia. Thallium-201 myocardial activity in a region of interest was determined continuously after i.v. administration by a gamma camera and computer program. Activity in the posterior wall was compared with that in the anterior wall in the same dog and the posterior wall of control dogs. Thallium-201 uptake was directly related to blood flow. With reactive hyperemia, there was a rapid and absolute increase in uptake followed by rapid washout; with ischemia, there was slow and decreased uptake followed by a slow washout. The calculated myocardial activity during washout in both ischemic and hyperemic areas approached values in control dogs long after blood flow had returned to baseline levels. Significant differences in washout slopes were found between the three groups of dogs (-0.156%/min in control dogs, -0.244%/min after reactive hyperemia, and -0.076%/min after transient ischemia, with half-washout times of 5.3 hours, 3.4 hours and 11.0 hours, respectively). These data suggest that both the initial decrease in activity in the ischemic area and the initial excess in the hyperemic area are corrected by different washout rates of ischemic and hyperemic cells during redistribution.