Deep learning-based attenuation correction method in 99mTc-GSA SPECT/CT hepatic imaging: a phantom study

This study aimed to evaluate a deep learning-based attenuation correction (AC) method to generate pseudo-computed tomography (CT) images from non-AC single-photon emission computed tomography images (SPECTNC) for AC in 99mTc-galactosyl human albumin diethylenetriamine pentaacetic acid (GSA) scintigraphy and to reduce patient dosage. A cycle-consistent generative network (CycleGAN) model was used to generate pseudo-CT images. The training datasets comprised approximately 850 liver phantom images obtained from SPECTNC and real CT images. The training datasets were then input to CycleGAN, and pseudo-CT images were output. SPECT images with real-time CT attenuation correction (SPECTCTAC) and pseudo-CT attenuation correction (SPECTGAN) were acquired. The difference in liver volume between real CT and pseudo-CT images was evaluated. Total counts and uniformity were then used to evaluate the effects of AC. Additionally, the similarity coefficients of SPECTCTAC and SPECTGAN were assessed using a structural similarity (SSIM) index. The pseudo-CT images produced a lower liver volume than the real CT images. SPECTCTAC exhibited a higher total count than SPECTNC and SPECTGAN, which were approximately 60% and 7% lower, respectively. The uniformities of SPECTCTAC and SPECTGAN were better than those of SPECTNC. The mean SSIM value for SPECTCTAC and SPECTGAN was 0.97. We proposed a deep learning-based AC approach to generate pseudo-CT images from SPECTNC images in 99mTc-GSA scintigraphy. SPECTGAN with AC using pseudo-CT images was similar to SPECTCTAC, demonstrating the possibility of SPECT/CT examination with reduced exposure to radiation.

Effect of resolution recovery using graph plots on regional cerebral blood flow in healthy volunteers

PURPOSE

We evaluated the effect of resolution recovery (RR) using graph plots on regional cerebral blood flow (rCBF) in brain perfusion single-photon emission computed tomography (SPECT) images derived from healthy volunteers and patients diagnosed with probable Alzheimer's disease.

METHOD

We acquired brain perfusion SPECT images with scatter correction (SC), computed tomography-based attenuation correction (CTAC), and RR from a three-dimensional brain phantom and from healthy volunteers. We then compared contrast-to-noise ratio, count density ratios, increase maps, and rCBF using statistical parametric mapping 8.

RESULTS

Regional brain counts were significantly increased from 20-24% with SC, CTAC, and RR compared with SC and CTAC. Mean CBF in healthy volunteers was 42.5 ± 5.4 mL/100 g/min. Average rCBF determined using SC, CTAC and RR increased 7.5, 2.0, and 3.7% at the thalamus, posterior cingulate, and whole brain, respectively, compared with SC and CTAC.

CONCLUSION

Resolution recovery caused variations in normal rCBF because counts increased in cerebral regions.

Does applying resolution recovery to normal databases confer an advantage over conventional 3D-stereotactic surface projection techniques?

We evaluated a novel normal database (NDB) generated using single photon emission computed tomography (SPECT) data obtained from healthy brains by using a SPECT/CT system, analyzed using a resolution recovery (RR) technique applied to the three-dimensional stereotactic surface projection (3D-SSP) technique. We used a three-dimensional ordered subset expectation maximization method (3D-OSEM) with applied scatter correction (SC), attenuation correction, and RR to reconstruct the data. We verified the accuracy of the novel NDB's values (Z, extent, and error scores), and compared the novel NDB to the 3D-SSP technique by using simulated misery perfusion-related patient data from a conventional NDB. In addition, Z, extent, and error scores at the precuneus, cuneus, and posterior cingulate were compared under different reconstruction conditions by using the patient data. In the simulation, Z scores decreased when using the novel NDB corrected using computed tomography-based attenuation correction (CTAC), SC, and RR. The extent scores of the posterior cingulate increased using the novel NDB, relative to the other NDBs. The error score with the novel NDB without RR decreased by 15% compared to that of the conventional NDB. Z scores generated from patient data decreased in the novel NDB with RR. The extent scores tended to decrease in the novel NDB with RR. The extent scores in the novel NDB with RR improved at the posterior cingulate, compared to the scores with the other NDBs. However, applying RR to the novel NDB conferred no advantage because the cut-off of the current Z score must be reconsidered when using the additive RR technique.

Evaluation of the Effect of Attenuation Correction by External CT in a Semiconductor SPECT

The discovery of NM530c with a cadmium-zinc-telluride detector (CdZnTe-SPECT) is superior to the conventional Anger-type SPECT with a sodium-iodide detector (NaI-SPECT) in terms of sensitivity and spatial resolution. However, in the clinical example, even in CdZnTe-SPECT, a count decrease in myocardium due to the attenuation of the gamma ray is an issue. This study was conducted to evaluate the effect of computed tomography attenuation correction (CTAC) in CdZnTe-SPECT with the help of external CT. We evaluated the revision effect of uniformity, influence by the difference in attenuation distance, contrast ratio, an uptake rate using the heart phantom. As a result of the phantom studies, a good revision effect was obtained. In the clinical study, there was a statistical significant difference between the contrast ratio before and after CTAC in the inferior wall. In addition, the contrast ratio before and after CTAC in CdZnTe-SPECT image was equal to those of NaI-SPECT image. It was suggested that CTAC using external CT in CdZnTe-SPECT was clinically useful for inferior wall.

Evaluation of Resolution Recovery for Each Collimator in Brain Perfusion Image

PURPOSE

This study aimed to verify the resolution recovery for each collimator in the brain perfusion image.

METHOD

To verify the effect of the resolution recovery for each collimator, we evaluated via the three-dimensional brain phantom (phantom) and the normal brain perfusion single photon emission computed tomography (SPECT) data. These data were reconstructed using the three-dimensional ordered subset expectation maximization method (3D-OSEM) (Evolution for bone^TM) that was performed with scatter correction, attenuation correction, and resolution recovery (RR). The performance of resolution recovery was evaluated in the two collimator systems (ELEGP and MEGP) reconstruction condition via the contrast value, mean counts, normalized mean square error (NMSE), and regional brain activity.

RESULT

In the "with resolution recovery (+RR)", the NMSE indicated minimum value with SI (subset×iteration) = 100, cut-off frequency (Fc) = 0.50 cycles/cm. The contrast value in the "+RR" increased 20% for the cortical region and decreased 28% and 6% at ELEGP collimator and MEGP collimator for the central region, as compared to the "without resolution recovery (-RR)". In the phantom study, the error of the brain activity using MEGP collimator at the temporal lobe and sub-lobar decreased 15%, compared with ELEGP collimator in the + RR. In the clinical study, the error of the regional brain activity using MEGP collimator in the "+RR" increased from 3% to 8%, compared with "-RR".

DISCUSSION

The accurate resolution recovery was obtained at SI = 100 and Fc = 0.50 cycles/cm. The contrast value and regional brain activity at the central region decreased due to incomplete resolution recovery by use of ELEGP collimator.

[Comparison of Quantitative Value of Dopamine Transporter Scintigraphy Calculated from Different Analytical Software]

In the dopamine transporter scintigraphy there are two quantitative analysis softwares, DaTView and DaTQUANT. The quantitative value of both software has to be treated independently because there is a difference between them in the point of how to set the region of interest on the striatum and the background, calculation formula of quantitation. And also DaTQUANT has a capability of performing anatomical standardization which DaTView does not have. The aim of this study was to evaluate the accuracy of registration on DaTQUANT using a phantom, and to evaluate the correlation between the quantitative values between DaTView and DaTQUANT using clinical data. As a result, the accuracy of registration was acceptable. Regardless of the degree of accumulation in the striatum, there was a high correlation to each analysis software (r>0.85).

[Influence of a radioisotope from out of the effective field of view in a semiconductor single photon emission computed tomography scanner]

Discovery NM 530c (CZT SPECT) is a new single photon emission computed tomography (SPECT) scanner using a cadmium-zinc-telluride (CZT) solid-state semiconductor detector technology. Due to multi-pinhole collimator design of this system, each CZT detector facing different direction and be able to get incidence radioactivity from radioisotopes (RIs) existing outside of effective field of view (EFOV). The purpose of this study is to verify its impact and compare it to a conventional Anger-type SPECT scanner (Discovery NM/CT 670 pro). We used (99m)TcO4(-) as radiation source and set it outside of the EFOV at several different positions (height and angle) and scanned by both the cameras. As a result, CZT SPECT got more influence compared to Anger-type SPECT. The impact was different according to its height. When using other RIs in CZT SPECT room, it is important to confirm the appropriate position against CZT SPECT during scan.

Influence of permittivity and electrical conductivity on image pattern of MRI

In proton density-weighted (PDW) MR imaging, the patterns of signal intensity vary depending on the imaged material, and change with the flip angle (FA) applied to the imaged material. The correlation between the pre-determined FA and the actual FA applied to imaged objects was investigated using 4 types of phantoms having different dielectric properties. PDW images were acquired using the spin-echo (SE) method and different pre-determined FA. Dependency of the signal intensity distribution in the phantom on the pre-determined FA differed among phantoms: patterns for water and 0.402 w/w% saline solution phantoms changed with the pre-determined FA, whereas those for olive oil and 4.02 w/w% saline solution phantoms were barely affected by the pre-determined FA. Causes of these phenomena were considered to be the differences between the pre-determined FA and the actual FA among the phantoms; differences were also influenced by the positioning of the phantom. Our study showed that the actual FA in the phantom is greater than the pre-determined FA in high permittivity media, whereas it is reduced by an increased conductivity of the media.

Visualization of stent lumen in MR imaging: relationship with stent design and RF direction

Magnetic resonance imaging (MRI) visualization of metallic stent lumens is possible if the stent structure counteracts eddy currents in the lumen induced by the radio frequency magnetic field, B(1). To examine the effectiveness of various stent designs in counteracting eddy currents, we anchored eight copper stent models and 2 commercially available nickel-titanium alloy (Nitinol) stents in a gel phantom, perpendicular or parallel to the direction of B(1). A mesh stent lumen showed hypointensity irrespective of its alignment relative to B(1). A solenoid stent lumen showed hypointensity with the stent axis parallel to B(1), but it had the same signal intensity as outside the lumen when perpendicular to B(1). A Moebius stent lumen showed no signal reduction, irrespective of alignment relative to B(1). Lumens of the commercially available stents showed hypointensity regardless of alignment relative to B(1). Computer simulation revealed that the signal intensities of the stents corresponded to magnetic flux densities of B(1) in the stents, which are modified by the structure of the stent. While in vivo MRI viewing of a Moebius stent lumen is likely possible regardless of axis alignment, inherent structural weakness may be problematic. As a more practical choice, the solenoid stent is easier to manufacture and generates no hypointensive signal when the axis is parallel to B(0).

[Achievement of causal inference in the social medicine in Japan]

As a condition to achieving an agreement of recognition on the causal relationship in medicine, we firstly explained Hume's problem and counterfactual model. We, however, emphasized that we believe in the existence of causality on medical issues in our daily lives. Therefore, we illustrated conditions when we usually believe in causality. On the other hand, we criticized two well-known key phrases, "lack of mechanism in epidemiology" and "black box in epidemiology", which have often been used in Japan for skeptic viewpoints against epidemiologic methods even if epidemiology is often used to elucidate a causal effect in medicine in the world. We emphasized that a priori determinations of levels for inference of mechanism is necessary. And, the level and feature of mechanism should be defined in concrete expressions. After explanation of these basic concepts, we mentioned a classic view on specific diseases and non-specific diseases which have not been sufficiently discussed enough yet in Japan. As an example, we used the statements in the Japanese Compensation Law for the Health Effect by Environmental Pollution. In Japan, the classification of these diseases has been confused with that between manifestational criteria of diseases and causal criteria of them. We described the basic concepts to illustrate the causal relationship between non-specific disease and its exposure by using attached figures. Actually, we cannot recognize disease occurrence as a specific disease for several reasons. We indicated that we can recognize the magnitude of effect by causal relationships in medicine as a quantitative continuous variable.

[An appraisal of the judgements of the Kumamoto Minamata Disease Certification Commission from May 1981 to July 1992 for applicants from December 1975 to April 1981]

The differences of the diagnosis from December 1975 to April 1981 and from May 1981 to July 1992 of the Committee on Certification of Minamata Disease based on the medical records of 3,870 applicants who had been examined from December 1975 to April 1981 by the Committee were compared and analyzed from a statistical point of view. Three hundred forty inhabitants from December 1975 to April 1981 and two hundred ninety eight inhabitants from May 1981 to July 1992, in total six hundred and thirty eight inhabitants, were certified to have Minamata disease by the Committee on Certification of Minamata Disease. One hundred and eleven inhabitants who were judged likely to have Minamata disease by application of the present criteria presented by the Japanese Environmental Agency in 1977 were certified by the committee from May 1981 to July 1992, and one hundred and thirty three inhabitants who were judged not likely to have Minamata disease by application of the present criteria were certified from May 1981 to July 1992. The author concluded that certification of the patients of Minamata disease by the Committee was inconsistent with the results of applying the present criteria to the data and that the prevalence of the symptoms of the inhabitants certified from December 1975 to April 1981 was inconsistent with that from May 1981 to July 1992.

A case of prostatic cancer metastasizing to the orbit

PURPOSE

We report on a case of prostatic cancer with multiple bone metastases, including right orbital involvement.

METHODS/RESULTS

Hormonal treatment and local irradiation to the right orbit were performed. Subjective symptoms with exophthalmos and pain disappeared.

CONCLUSIONS

We report on a case of prostatic cancer metastasizing to the right orbital bone.

[Causal inference in medicine: a reaction to the report, "incidence of Minamata disease in communities along the Agano River, Niigata, Japan--patterns of the exposure and official diagnosis of patients"]

Kondo's "Incidence of Minamata Disease in Communities along the Agano River, Niigata, Japan (Jap. J. Hyg. 51:599-611;1996)" is critically reviewed. The data of the article were obtained from most of the residents living in the Agano river villages where Minamata disease was discovered in June, 1965. However, sampling proportions were much different between in the population base and in the cases. The method of identification of cases from the data and the reason for the difference were not clearly demonstrated. The citations of reference articles are insufficient despite the fact that other epidemiologic studies on methyl-mercury poisoning have been reported not only in Japan, but also around the world. His "analysis of the recognized patients" is erroneous. Both the sampling scheme of information of hair mercury and the modeling of the analysis are based on Kondo's arbitrary interpretation, not on epidemiologic theory. His "analysis of the rejected applicants" is also erroneous. His calculations of the attributable proportion are incorrect and self-induced in both the assignments of data and analysis of data. Kondo has failed to study the epidemiologic theories in light of changes in the field. Therefore, his article is lacking in epidemiologic theory, a logical base and scientific inference. In Japan, epidemiologic methodology has rarely been used in studies on Minamata Disease in either Kumamoto and Niigata. The government has used neurologically specific diagnosis based on combinations of symptoms to judge the causality between each of symptoms and methyl-mercury poisoning. Epidemiologic data obtained in Minamata, Kumamoto in 1971 indicate that the criteria set by the government in 1977 have produced much more false-negative patients than false-positive patients. As a result, a huge number of symptomatic patients, including those with peripheral neuropathy or with constriction of the visual field, did not receive any help or compensation until 1995. The authors emphasize that the causal relationship between each symptom and methyl-mercury exposure should be reevaluated epidemiologically in Japan.

[An appraisal on the judgements of the Kumamoto Minamata Disease Certification Commission]

Medical records of 3,870 applicants living near the Shiranui sea coast who had been examined from August 1975 to April 1981 by the Committee on Certification of Minamata Disease were analyzed from the statistical point of view. The author analyzed the pattern of signs and reevaluated the applicants' records. Three hundred forty applicants (8.8%) were certified to have Minamata disease by the Committee on Certification of Minamata Disease. By application of the present criteria presented by the Japanese Environmental Agency in 1977 to the records, 947 inhabitants (27.9%) were judged likely to have Minamata disease. The author concluded that the certification of the patients of Minamata disease by the Committee was inconsistent with the results of applying the present criteria to the data and that the number of patients certified by the Committee to have Minamata disease was too low.

Factors affecting the occurrence of urothelial tumors in dye workers exposed to aromatic amines

BACKGROUND

Past studies have analyzed individual jobs in dyestuff factories, materials manufactured and handled, age at exposure, and the duration of exposure in factories as factors related to the occurrence of urothelial tumors. None of these studies was based on long-term observation, and the factors involved in the occurrence of urothelial tumors remain controversial. In this study, various factors that may affect the occurrence of urothelial tumors in dye workers were assessed by multivariate analysis.

METHODS

Three hundred and sixty-three workers in nine member factories of the Dyestuff Industrial Cooperative Association were included the study. Factory A is a large dyestuff chemical factory in Wakayama City with 218 dye workers. The other eight smaller factories employ a total of 145 dye workers. Correlations of tumor occurrence with a variety of factors, such as dyestuff intermediates manufactured and handled, types of job in the factory, age at the beginning of occupational exposure, and the duration of exposure were examined by multivariate analysis using multiple logistic models.

RESULTS

Urothelial tumors were found in 58 (16.0%) of the 363 dye workers in the nine member factories of the Cooperative Association examined in the present study. The incidence in workers in Factory A, 5.5% (12 patients), was significantly (P < 0.01) lower than the overall incidence, while that in the eight small factories, 31.7% (46 patients), was significantly (P < 0.01) higher than the overall incidence. The risk factors significantly related to tumor occurrence in the 363 dye workers were benzidine (odds ratio, 8.302) as a dyestuff intermediate, manufacturing work (odds ratio, 4.631), and a long period of exposure (odds ratio, 1.018). Correlations of the tumor occurrence with the various factors were examined by multivariate analysis using multiple logistic models. In the total of 363 workers, benzidine as an intermediate (P < 0.05), manufacturing work (P < 0.01) and the duration of exposure (P < 0.01) were found to have contributed to the urothelial tumor occurrence. In Factory A, benzidine as an intermediate (P < 0.01) and duration of exposure (P < 0.05) contributed significantly to tumor occurrence.

CONCLUSIONS

1) The manufacturing and handling of benzidine and duration of exposure contribute significantly to the occurrence of occupational urothelial tumor, the former more strongly than the latter; 2) the contribution of different job types to tumor occurrence may be dependent upon the industrial health and safety practices in each factory.

[A case of clear cell adenocarcinoma of the female urethra]

A case of clear cell adenocarcinoma arising from the female urethra is described. Histologically, solid and glandular areas consisted of clear cells. The tumor cells were stained positively with antibodies to prostate specific antigen (PSA) and prostatic acid phosphatase (PAP), suggesting that the clear cell adenocarcinoma arises from the female paraurethral duct, rather than embryonic remnant.

Clear cell adenocarcinoma of the female urethra showing positive staining with antibodies to prostate-specific antigen and prostatic acid phosphatase

A case of clear cell adenocarcinoma arising from the female urethra is described. Histologically, solid and glandular areas consisted of clear cells. The tumor cells stained positively with antibodies to prostate-specific antigen and prostatic acid phosphatase, suggesting that the clear cell adenocarcinoma arises from the female paraurethral duct, rather than embryonic remnants.

[Prostate specific antigen in patients with prostatic cancer--clinical usefulness of its measurement with sensitive enzyme immunoassay, TOSOH II PA assay]

The TOSOH II PA (AIA-PACK PA in the U.S.A.) monoclonal immunoenzyme assay was used and the clinical usefulness of prostate specific antigen (PSA) was evaluated in 39 men with prostatic cancer and 32 men with benign prostatic hyperplasia (BPH) confirmed pathologically. We evaluated the lower limit of detection in this assay by the mean PSA level plue 3 standard deviations in 5 separate experiments with a zero control sera as well as the mean PSA level minus 3 standard deviations in 5 separate experiments with serial dilutions of a known concentration of PSA. PSA concentrations of 0 to 0.25 ng/ml could not be distinguished from the zero control. Therefore, we set the lower limit of detection for the assay as 0.25 ng/ml. At our laboratory, the normal standard value was determined by the mean PSA level plus 3 standard deviations in 79 healthy men as 2.3 ng/ml. Of patients that underwent radical cystoprostatectomy for bladder cancer, all had PSA levels less than 0.25 ng/ml, while only 6% had PAP levels less than 0.11 ng/ml, the lower limit of detection in the TOSOH II PAP assay. We compared TOSOH II PA with Markit PA, a commonly used assay in Japan. Although there was a close linear correlation (r = 0.90) between the TOSOH II PA and Markit PA, the difference of slope in the linear regression lines was great, it was thought due to anti-PSA antibodies in each assay recognizing different epitopes of PSA in the blood.(ABSTRACT TRUNCATED AT 250 WORDS)

A case of Klebsiella pneumoniae endophthalmitis metastasized from prostatitis

A case of Klebsiella pneumoniae endophthalmitis metastasized from prostatitis is reported. A 58-year-old alcoholismic man with diabetic diathesis suffered from endophthalmitis which required enucleation of his left eye, when he interrupted the treatment of prostatitis. Metastatic bacterial endophthalmitis from urinary tract infection is rare.

Determination of aspoxicillin in broncho-alveolar lavage fluid by high-performance liquid chromatography with photolysis and electrochemical detection

A determination method for the penicillin antibiotic aspoxicillin in broncho-alveolar lavage fluid has been developed, involving high-performance liquid chromatography and post-column photolysis. The method enabled the determination of aspoxicillin at concentrations below 100 ng/ml, with a linear calibration curve at concentrations of 1-1000 ng/ml for 100 microliters of lavage fluid. The detection limit was 1 ng/ml at a signal-to-noise ratio of 3:1.

[A case of deoxycorticosterone-producing adrenal tumor]

We present a case of a 11-deoxycorticosterone (DOC)-producing adrenocortical tumor. A 55-year-old female was admitted to our hospital with the chief complaints of sustained hypertension and weakness of lower extremities. A laboratory study revealed a decrease in the serum potassium level and plasma renin activity, a normal level of plasma aldosterone and a significant elevation of plasma DOC and 18-OH-DOC levels. The plasma DOC level was increased by ACTH stimulation and was not suppressed by dexamethasone. The tumor appeared at a low intensity of the T1 weighted image of magnetic resonance imaging (MRI) and at a high intensity on the T2 weighted image. Left adrenalectomy was performed and histological examination revealed a benign adrenal adenoma. Postoperatively, the abnormal blood pressure, serum potassium level and plasma level of DOC and 18-OH-DOC became normal.

[A clinical review of 19 patients with pheochromocytoma]

Nineteen cases of pheochromocytoma were experienced at our department between 1979 and 1990. Nine patients were males and 10 females with an average of 42.4 years old. In 18 patients the tumor was located in the adrenal gland (9 in right, 5 in left and 4 in bilateral adrenal gland), while in one patient whose original tumor had been resected 15 years earlier, the tumor had recurred in the extra-adrenal gland and was surgically extirpated revealing a malignant pheochromocytoma by histological examination. Hypertension was seen in 16 patients; 14 had paroxysmal and 2 had sustained hypertension. In 3 patients, hypertension was not observed. Familial pheochromocytoma was seen in 5 patients. Three patients had Sipple syndrome. Computed tomographic scan and magnetic resonance imaging were very useful techniques in preoperatively localizing the tumor. Even in the cases treated with alpha- or beta-blocker agents preoperatively, significant hypotension was observed immediately after resection of the tumor and treatment with norepinephrine or rapid blood transfusion or both was needed. Although meticulous care with alpha- and beta-blockers is important, surgical treatment of pheochromocytoma should spare the surgeon of unnecessary anxiety.

[Evaluation of beta-glucuronidase activity for the isolation of diarrhea-causing Escherichia coli]

To compare the isolating efficiency of diarrhea-causing Escherichia coli between Fluorocult agar plates, which reveal the beta-glucuronidase activity of E. coli, and a combination of SS and DHL agar plates, a total of 330 fecal specimens collected from outpatients were examined. Diarrhea-causing E. coli, identified by serological and toxigenic characters, were demonstrated in 52 samples. Among these specimens, 35 samples tested were positive on the Fluorocult agar plates, and 26 samples on the combination of SS and DHL agar plates. However, only 10 samples were positive on both the Fluorocult agar plates and the combination of SS and DHL agar plates. Thus, using Fluorocult agar plates for the isolation of diarrhea-causing E. coli in addition to the conventional SS and DHL agar plates will improve isolating efficacy.

Lowering of plasma free tryptophan in normal and portacaval shunt dogs

The purpose of this study was to develop a method which would produce immediate and sustained lowering of plasma free tryptophan. Glucose, insulin, and mixtures of the two in different concentrations were infused into dogs over a period of 6 hr. Blood was sampled during the course of the infusion for assay of plasma free and total tryptophan, free fatty acids, glucose, and insulin. The infusate found to produce the most significant and sustained reduction in plasma free tryptophan in normal dogs was a mixture of 25% glucose and insulin. The lowering ranged from 26 to 47% during the course of the infusion. When the same infusion mixture was administered to dogs with established portacaval shunts, and elevated plasma free tryptophan concentrations (3.3 +/- 0.3 micrograms/ml compared to normal dogs which had 1.9 +/- 0.1 micrograms/ml), there was a 35% reduction to normal levels (2.0-2.2 micrograms/ml). A glucose-insulin mixture has, therefore, been found which, upon infusion into dogs, significantly lowers plasma free tryptophan levels. The effect of such an infusion on the plasma levels of free tryptophan, and the clinical course of patients with hepatic encephalopathy remains to be determined.

Cytologic and histologic correlation in primary lung cancer. A study of 154 cases with resectable tumors

The accuracy of cytologic diagnosis and typing was examined in 154 patients, 113 males and 41 females, who underwent radical surgery during the past six years. There were 42 central and 112 peripheral lesions: 6 adenocarcinomas and 28 squamous-cell carcinomas were centrally located and 69 adenocarcinomas and 27 squamous-cell carcinomas were peripherally located. Repetition of sputum sampling at least three times was preferred, especially in central lesions, which were detected in 57% to 64% of the cases by either three-day-pooled or aerosol-induced specimens. Peripheral lesions required brushing to enhance the accuracy. The overall typing accuracy was 64.3%, ranging from 83.6% in squamous-cell carcinoma to 25.0% in large-cell carcinoma. Cytologic positivity correlated well with the finding of tumors more than 3 cm in diameter. Adenocarcinoma and squamous-cell carcinoma showed no significant difference in frequency of regional lymph nodal metastases. The value of judging the accuracy of cytologic diagnosis and typing on the histologic evaluation of the entire resected lesion, rather than on biopsy specimens, is emphasized.

[Anticancer drug sensitivity tested by tumor stem cell assay]

Accurate in vitro anticancer drug sensitivity is helpful for successful chemotherapy of cancer patients. The purpose of the present study was to evaluate the tumor stem cell assay for the selection of effective drugs for individual patients with cancer and for the in vitro phase II screening of new anticancer drugs. Sixty-six specimens obtained from cancer patients were tested drug sensitivity by this assay. The results showed that this assay as an excellent technique for testing in vitro sensitivity of anticancer drugs against tumor cells from specimens removed from individual patients. The in vitro results correlated with in vivo response data in 93% of the instances observed in vitro-in vivo associations and a true negative rate was 100%.

Tumor stem cell assay for detecting metastases of human lung cancer

We applied a tumor stem cell assay using an enriched double-layered soft agar system for the detection of metastatic sites of lung cancer. Lung cancer colonies grew from 7 of 10 effusions cytologically positive for tumor cells and 7 of 10 bone marrow aspirates cytologically and histologically positive for tumor cells. Twenty-six of 29 bone marrow aspirates cytologically and histologically negative for tumor cells showed no colony growth. However, the remaining three bone marrow aspirates, which were obtained from patients with small cell lung cancer, formed colonies in soft agar. These results indicate that the tumor stem cell assay is useful for detecting metastatic sites of lung cancer.

Cytological and histological correlation of primary lung cancer: a preliminary study of 106 cases with resectable tumors

In order to increase the accuracy of diagnosis in lung cancer, analysis concerning cytological and histological correlation was attempted. The present study consists of 106 patients, who were seen during the past approximately five years and underwent radical surgery to remove tumors completely; mere biopsy specimens were excluded. These patients were 63 years old on the average, 78 males and 28 females, 29 cases of the hilar type (H) and 77 of the peripheral type (P), and 27 and 76 cases of the clinical stage I in H and P, respectively. Histologically, there were 53 adenocarcinomas (Ad), 38 squamous cell carcinomas (Sq), 4 adenosquamous cell carcinomas (Ad + Sq), 5 large cell carcinomas (LCC), and 6 small cell carcinomas (SCC); among them, 3 Ad and 21 Sq in H, and 50 Ad and 17 Sq in P. The overall positive percentages were 65.5 (H) and 26.0 (P) by combination of spontaneous, airsol-induced and Saccomanno's methods, against 96.6 (H) and 72.8 (P) with inclusion of brushing method. 94.8% of Sq in H and 66.7% of Ad and 70.6% of Sq in P were positive by the brushing. A comparative study of these four methods, performed at least once on the same patient, also confirmed the superiority of brushing. Cyto- and histological agreement was 21/21 (100%) for Sq in H, whereas 30/34 (88.2%) for Ad and 13/15 (86.7%) for Sq in P. In conclusion, cyto- and histological findings in H and P corresponded well, and as far as cytology of peripheral type is concerned, a combined method, especially with brushing, is strongly recommended.

Transient ischemic attacks: racial differences, treatment, and prognosis

Prognosis of transient ischemic attack (TIA) in 45 patients, diagnosed as TIA out of 75 suspected TIAs, was investigated for an average follow-up of 12.9 months. Twelve (27%) of the 45 patients progressed to complete stroke during the follow-up period. Patients with severe atherosclerotic lesions and with intracranial arterial lesions or with lesions of both intracranial and extracranial sites were predominant among the 29 cases examined angiographically, and the majority progressed to stroke. The prognosis was poorer than in the cases with mild atherosclerotic lesions or cases with only extracranial arterial lesions. From such characteristics of cerebral atherosclerosis of TIA in the Japanese with predominant intracranial severe arterial lesions, a different genesis for the development of cerebral atherosclerosis between Japanese and Americans or other Caucasians may be expected in cases with TIAs. With respect to the relation of recurrence of TIA to prognosis, a single episode of TIA in the past placed the patient at a greater risk of early infarction, where a high incidence (57%) of progression to stroke was found during the follow-up period. Treatment by superficial temporal artery to middle cerebral artery anastomosis or anticoagulant drug medication seemed to improve the prognosis of TIA as compared with antiplatelet aggregation therapy. These results suggest that embolus formation from an embolic source of arterial lesions may play some part in the pathogenesis of TIA and occurrence of subsequent stroke.

Pretreatment serum albumin concentration and lactic dehydrogenase activity as prognostic factors in patients with small cell lung cancer

Pretreatment laboratory parameters were analyzed as prognostic factors in patients with small cell lung cancer. Serum lactic dehydrogenase activity, serum albumin concentration, PPD skin reaction, and peripheral lymphocyte count were of prognostic importance. When these factors were evaluated by multivariate analysis together with performance status and disease extent, lactic dehydrogenase and albumin were the most influential factors related to survival.

Bone marrow examination for detection of metastasis in patients with bronchogenic carcinoma: an evaluation of 107 patients

As a staging procedure before treatment, examination of bone marrow from the posterior iliac crest was performed on a total of 107 patients with bronchogenic carcinoma. Among them, 11 patients (10.3%) had metastasis in the bone marrow: five of 39 adenocarcinomas, five of 33 small cell carcinomas, one of four large cell carcinomas, and none of 31 epidermoid carcinomas. Leukoerythroblastosis was found exclusively in the patients with metastasis, although the presence of tumor cells in the bone marrow did not correlate well with peripheral blood cell counts. Survival following an intensive chemotherapy in patients with bone marrow metastasis was substantially longer for those with small cell carcinoma than for those with other histologic types of bronchogenic carcinoma.

Hemodynamic and volume characteristics, and peripheral plasma renin activity in Takayasu's arteritis

Hemodynamic and volume characteristics, and/or peripheral plasma renin activity were investigated in 19 patients with Takayasu's arteritis who included 8 hypertensive patients with renal arterial disease and 11 normotensive patients. In hypertensive patients, mean arterial pressure had an inverse correlation with cardiac index, a direct correlation with total peripheral resistance index and no correlation with blood volume. These hemodynamic and volume characteristics were different from those of hypertension with renal arterial disease previously reported. High plasma renin activity was presented in not only hypertensive patients with renal arterial disease but normotensive patients. The investigation of high plasma renin activity in Takayasu's arteritis must be also directed to the mechanism except renal arterial lesions.

Percutaneous transhepatic drainage: experience in 100 cases

A two-step procedure for percutaneous transhepatic drainage (PTD) of the biliary tract was attempted on 101 patients with obstructive jaundice, 29 with benign and 71 with malignant lesions, and was successful in 100. With this procedure, marked clinical improvement, with reduction in levels of serum bilirubin, SGOT, SGPT and alkaline phosphatase, was achieved after 1-2 weeks as a preoperative step or for continuous drainage in inoperable cases. In one patient 8 dys after PTD, however, a complicating large intrahepatic hematoma proved fatal. Emergency operation was necessary in three of the four patients who developed bile peritonitis due to dislocation of the catheter and in one with intra-abdominal bleeding. Our results suggest that this procedure is very useful in the diagnosis and management of certain obstructive diseases of the biliary tract.