Reversibility of brain tissue loss in anorexia nervosa assessed with a computerized Talairach 3-D proportional grid

We describe the results of our follow-up magnetic resonance imaging (MRI) study of underweight patients with anorexia nervosa, using rigorous methodology to control for head position across time. All subjects first underwent an initial scan and rescan to verify that our computerized three-dimensional co-planar grid method for volume measurement was reliable and accurate, regardless of head positioning. After a period of several months, subjects had a follow-up scan to assess for changes that may have occurred following significant weight gain. Ventricular and total brain volume measurements from the initial scans were compared with the scans from an age- and sex-matched normal control group to determine whether we could replicate previous findings of ventricular enlargement compared with controls and whether brain volume is reduced compared with controls. Anorexic subjects had significantly larger ventricles when compared with normal controls but did not differ significantly in total brain volume. Using a repeated measures analysis of variance, a priori contrasts compared the initial/rescan pair volumes with each other and the initial/rescan pair volumes with the follow-up volume. These analyses showed that ventricular and total brain volumes derived from the initial/rescan pair were nearly identical, but that at follow-up ventricular volume decreased significantly and total brain volume increased significantly after weight gain.

Plasminogen activator inhibitor-1 in nonobese subjects with non-insulin-dependent diabetes mellitus

Elevated plasma levels of plasminogen activator inhibitor-1 (PAI-1) have been shown to be a risk factor for the development of vascular complications in obese and hyperinsulinemic non-insulin-dependent diabetes (NIDDM) patients. To clarify whether PAI-1 also plays an essential role in the development of such complications in NIDDM patients without obesity or hyperinsulinemia, PAI-1 was analyzed in relation to blood pressure, fasting plasma levels of glucose (FPG), hemoglobin A1C (HbA1c), immunoreactive insulin (F-IRI), C-peptide (CPR), total cholesterol (TC), triglyceride (TGL), and HDL-cholesterol (HDL-C) in 77 NIDDM patients and 10 healthy control subjects. The NIDDM patients were not obese (body mass index [BMI]:<26 kg/m2) or hyperinsulinemic, and BMI in the controls was between 19 and 24 kg/m2. In addition, parameters of insulin secretion reserve, including sigmaIRI, insulinogenic index, and CPR at 5 min after glucagon loading, were evaluated simultaneously. Plasma levels of PAI-1 were higher in the NIDDM group (9.3+/-0.9 ng/ml) than in the controls (4.3+/-0.7 ng/ml;P<0.01). Levels of FPG and HbA1c were also elevated in the NIDDM group (P<0.05 for each), but F-IRI did not differ between the two groups. However, multiple regression analysis revealed no significant correlation in the NIDDM between PAI-1 and F-IRI or the parameters of insulin secretion reserve. Regardless of the presence or absence of vascular complications, PAI-1 did not vary significantly in the NIDDM. These findings suggest that the effects of PAI-1 on the development of diabetic complications in NIDDM patients may not proceed in the same way in those with versus those without obesity or hyperinsulinemia, because no correlation was found between PAI-1 and insulin secretion reserve, while plasma levels of PAI-1 were higher in the NIDDM group than in the controls.

Effects of long-term psychological stress on sexual behavior and brain catecholamine levels

The effects of long-term psychological stress on sexual behavior and brain catecholamines were investigated in rats. Stress was applied using the communication box developed by Ogawa and Kuwabara (1996), and a psychological stress group (n = 12), a physical stress group (n = 5), and a control group (n = 5) were established. Stress was applied for 1 hour every day for 10 consecutive weeks. Sexual behavior was observed before the start of exposure to stress and 2, 4, 6, 8, and 10 weeks thereafter. The results showed that long-term psychological stress impaired the sexual behavior of male rats. Long-term psychological stress decreased the concentrations of catecholamine and its metabolites in the brain, especially in the medial preoptic area (MPOA). Thus, we hypothesized that low catecholamine neurotransmission in the brain results in impairment of male rat sexual behavior. We then tried to restore the impaired sexual behavior by administration of a cerebral-activating drug, indeloxazine hydrochloride. The administration of indeloxazine hydrochloride for a 3-week period restored the sexual behavior that had been impaired by long-term psychological stress. These present results suggest that impairment of neurotransmission in the central nervous system could be a cause of sexual dysfunction, and activation of neurotransmission may result in restoration of impaired male sexual behavior.

Release of fructose and hexose phosphates from perivascular cells induced by low density lipoprotein and acceleration of protein glycation in vitro

We investigated whether low density lipoprotein (LDL) under oxidative stress might induce the release of fructose, glucose-6-phosphate and fructose-6-phosphate from perivascular cells, and also whether these substances might accelerate the formation of advanced glycation end products (AGE) from proteins in vitro. When vascular smooth muscle cells were incubated with LDL in Ham's F10 at 37 degrees C for 48 h. release of all these substances was increased dose-dependently by oxidized LDL. Fructose release was increased in a dose-dependent manner by glucose. Indomethacin (20 microM) significantly (P < 0.01) suppressed the release of fructose (25.4 +/- 15.7% of control) and hexose phosphates (29.4 +/- 4.0) with the inhibition of release of lactate dehydrogenase (35.5 +/- 4.9) as well as probucol, whereas an aldose reductase inhibitor, epalrestat, significantly (P < 0.001) inhibited only the fructose release (0.9 +/- 0.8). Release of fructose and hexose phosphates from vascular endothelial cells was also induced by oxidized LDL. AGE immunoreactivities and AGE-related fluorescence formed from proteins and glucose were significantly increased (P < 0.001) in the presence of small amounts of the cellular glucose metabolites (6.6%) with glucose (93.4%). These data suggest that release of potent AGE initiators, fructose and hexose phosphates, from perivascular cells induced by oxidized LDL may be an important phenomenon for vascular complications.

Localized right ventricular structural abnormalities in patients with idiopathic ventricular fibrillation: magnetic resonance imaging study

Lethal arrhythmias, including ventricular tachycardia and ventricular fibrillation, may occur in the absence of apparent morphological abnormalities. However, a recent study using magnetic resonance imaging (MRI) has suggested that localized, minor structural abnormalities of the right ventricle are responsible for right ventricular outflow tract ventricular tachycardia in a number of patients. We demonstrated regional wall thinning and systolic dyskinesia of the right ventricle by MRI in two patients with idiopathic ventricular fibrillation in whom other cardiac imaging modalities failed to show abnormalities. This finding implies that minor structural abnormalities do exist in patients with so-called idiopathic ventricular fibrillation.

[Regulators of angiogenesis]

Endothelial cells lining the lumen of vessels are maintained in the quiescent state and play important physiological roles. Yet, they can be de-differentiated and become one of the most rapidly proliferating of all cell types when stimulated. Angiogenesis or neovascularization is defined as the formation of new capillary vessels from existent microvessels, which plays a major role in the evolvement of a vascular supply in tissue during development or remodeling and disease. Angiogenesis is believed to be regulated by the balance between inducers and inhibitors. In this review article, I will summarize the molecules that regulate the process of angiogenesis.

[Surgical repair of atrial septal defect and tricuspid regurgitation in a 79-year-old man: a case report]

A 79-year-old man with atrial septal defect (ASD) and tricuspid regurgitation was successfully operated upon. Preoperative examinations showed atrial fibrillation, moderate pulmonary hypertension and lung dysfunction. Direct closure of the ASD accompanying with tricuspid annuloplasty was performed. Postoperative administration of catecholamines continued for twenty-six days to maintain hemodynamics. An intratracheal tube was extubated two days after the operation. However, an additional respiratory support using a nasal continuous positive airway pressure method was required for six days. His postoperative physical activity has been improved with class I of the New York Heart Association classification. Surgical intervention may be the treatment of choice for aged patients over 70 years with an ASD.

Tissue factor induces migration of cultured aortic smooth muscle cells

Tissue factor (TF) plays a key role as a primary initiator on the extrinsic coagulation cascade. Recently, upregulation of TF has been reported in human atherosclerotic lesions. We investigated the effects of TF on migration and proliferation of cultured smooth muscle cells (SMCs) from rabbit aortas. We tested three kinds of recombinant human TF (L-TF: the full length of TF with relipidation, NL-TF: the full length of TF without relipidation, and S-TF: a soluble form of TF1-219). Only L-TF had coagulant activity. All kinds of TF showed the chemotactic migration activity for SMCs. The migration ability of TFs was comparable to those of platelet-derived growth factor (PDGF)-BB and basic fibroblast-growth factor (bFGF), and was inhibited by anti-TF polyclonal and monoclonal antibodies. On the other hand, none of the forms of TF induced SMC proliferation. These results indicate that TF is not only a coagulation factor but also a strong chemotactic factor for vascular SMCs, and suggest that TF could play an important role in atherogenesis as well as in hemostasis and thrombosis.

Three-year follow-up after implantation of metallic coronary-artery stents

BACKGROUND

Coronary-artery stents are known to reduce rates of restenosis after coronary angioplasty, but it is uncertain how long this benefit is maintained.

METHODS

We evaluated clinical and angiographic follow-up information for up to three years after the implantation of Palmaz-Schatz metallic coronary-artery stents in 143 patients with 147 lesions of native coronary arteries.

RESULTS

The rate of survival free of myocardial infarction, bypass surgery, and repeated coronary angioplasty for stented lesions was 74.6 percent at three years. After 14 months, revascularization of the stented lesion was necessary in only three patients (2.1 percent). In contrast, coronary angioplasty for a new lesion was required in 11 patients (7.7 percent). Follow-up coronary angiography of 137 lesions at six months, 114 lesions at one year, and 72 lesions at three years revealed a decrease in minimal luminal diameter from 2.54 +/- 0.44 mm immediately after stent implantation to 1.87 +/- 0.56 mm at six months, but no further decrease in diameter at one year (in patients with paired angiograms, 1.95 +/- 0.49 mm at both six months and one year). Significant late improvement in luminal diameter was observed at three years (in patients with paired angiograms, 1.94 +/- 0.48 mm at six months and 2.09 +/- 0.48 mm at three years; P < 0.001).

CONCLUSIONS

Clinical and angiographic outcomes up to three years after coronary-artery stenting were favorable, with a low rate of revascularization of the stented lesions. Late improvement in luminal diameter appears to occur between six months and three years.

Ligand-independent activation of the glucocorticoid receptor by ursodeoxycholic acid. Repression of IFN-gamma-induced MHC class II gene expression via a glucocorticoid receptor-dependent pathway

The therapeutic effectiveness of ursodeoxycholic acid (UDCA) for various autoimmune liver diseases strongly indicates that UDCA possesses immunomodulatory activities. Experimental evidence also supports this notion, since, for example, UDCA has been shown to suppress secretion of IL-2, IL-4, and IFN-gamma from activated T lymphocytes, and Ig production from B lymphocytes. To investigate the mechanical background of UDCA-mediated immunomodulation, we asked whether UDCA interacts with the intracellular signal transduction pathway, especially whether it is involved in immunosuppressive glucocorticoid hormone action. For this purpose, we used a cloned Chinese hamster ovary cell line, CHOpMTGR, in which glucocorticoid receptor cDNA was stably integrated. In immunocytochemical analysis, we found that treatment with UDCA promoted the nuclear translocation of the glucocorticoid receptor in a ligand-independent fashion, which was further confirmed by immunoprecipitation assays. Moreover, the translocated glucocorticoid receptor demonstrated sequence-specific DNA binding activity. Transient transfection experiments revealed that treatment of the cells with UDCA marginally enhanced glucocorticoid-responsive gene expression. We also showed that UDCA suppressed IFN-gamma-mediated induction of MHC class II gene expression via the glucocorticoid receptor-mediated pathway. Together, UDCA-dependent promotion of translocation of the glucocorticoid receptor may be associated with, at least in part, its immunomodulatory action through glucocorticoid receptor-mediated gene regulation.

Ligand-independent activation of the glucocorticoid receptor by ursodeoxycholic acid. Repression of IFN-gamma-induced MHC class II gene expression via a glucocorticoid receptor-dependent pathway

The therapeutic effectiveness of ursodeoxycholic acid (UDCA) for various autoimmune liver diseases strongly indicates that UDCA possesses immunomodulatory activities. Experimental evidence also supports this notion, since, for example, UDCA has been shown to suppress secretion of IL-2, IL-4, and IFN-gamma from activated T lymphocytes, and Ig production from B lymphocytes. To investigate the mechanical background of UDCA-mediated immunomodulation, we asked whether UDCA interacts with the intracellular signal transduction pathway, especially whether it is involved in immunosuppressive glucocorticoid hormone action. For this purpose, we used a cloned Chinese hamster ovary cell line, CHOpMTGR, in which glucocorticoid receptor cDNA was stably integrated. In immunocytochemical analysis, we found that treatment with UDCA promoted the nuclear translocation of the glucocorticoid receptor in a ligand-independent fashion, which was further confirmed by immunoprecipitation assays. Moreover, the translocated glucocorticoid receptor demonstrated sequence-specific DNA binding activity. Transient transfection experiments revealed that treatment of the cells with UDCA marginally enhanced glucocorticoid-responsive gene expression. We also showed that UDCA suppressed IFN-gamma-mediated induction of MHC class II gene expression via the glucocorticoid receptor-mediated pathway. Together, UDCA-dependent promotion of translocation of the glucocorticoid receptor may be associated with, at least in part, its immunomodulatory action through glucocorticoid receptor-mediated gene regulation.

Efficient generation of recombinant adenoviruses using adenovirus DNA-terminal protein complex and a cosmid bearing the full-length virus genome

An efficient method of constructing recombinant adenoviruses (Ads) has been established. The expression unit to be introduced into recombinant Ad was first inserted into the unique Swa I site of the full-length Ad genome cloned in a cassette cosmid. The cassette bearing the expression unit was then cotransfected into human embryonic kidney 293 cells together with the Ad DNA-terminal protein complex digested at several sites with Eco T22I or Ase I/EcoRI. The use of the parent Ad DNA-terminal protein complex instead of the deproteinized Ad genome DNA allowed very efficient recovery of the desired recombinant Ad, and the above restriction digestion drastically reduced regeneration of the parent virus. Several hundred virus clones were readily obtained in each experiment, and about 70% of the clones were the desired recombinant viruses. Furthermore, because the cassette contained the full-length Ad genome, any position of the genome could be easily modified to develop a new vector design. We established construction systems for two types of Ad vectors, the E1-substitution type and the E4-insertion type. This method may greatly facilitate the application of recombinant Ads and should be useful for further improvement of Ad vectors.

Fetal alcohol syndrome: craniofacial and central nervous system manifestations

Magnetic resonance imaging (MRI) is undertaken on fetal alcohol syndrome (FAS) subjects to document central nervous system (CNS) anomalies. The abnormalities found include agenesis and hypoplasia of the corpus callosum, cavum septi pellucidi, cavum vergae, ventriculomegaly, hypoplasia of inferior olivary eminences, small brain stem, and micrencephaly. Craniofacial anomalies range from the well-recognized FAS physiognomy to the more severe frontonasal "dysplasia" (median cleft face). CNS and craniofacial abnormalities are predominantly symmetric and central or midline. The association of these anomalies becomes self-evident with recognition of the concept of the midline as a special developmental field, vulnerable to adverse factors during embryogenesis and fetal growth and development.

A novel human serum lectin with collagen- and fibrinogen-like domains that functions as an opsonin

Collectins are C-type animal lectins with both collagenous and carbohydrate recognition domains and are involved in the first line host defense against pathogens. We report here a novel Ca(2+)-dependent and GlcNAc-binding lectin consisting of subunits of 35 kDa (P35) with a collagen-like sequence. When P35 is isolated from human serum, it forms a homopolymer by means of intermolecular disulfide bonding, as is the case with collectins. P35 cDNA was cloned from a human liver cDNA library, and the deduced amino acid sequence of 313 residues revealed that the mature form of P35 consists mainly of collagen- and fibrinogen-like domains. The latter contained two potential Ca(2+)-binding sites that may be involved in carbohydrate binding. The overall sequence of P35 was highly homologous to porcine ficolins alpha and beta. Northern blots of various human tissues showed that the major product of the 1.3-kilobase-long P35 transcript is expressed in liver. P35 enhanced phagocytosis of Salmonella typhimurium by neutrophils, suggesting an opsonic effect via the collagen region. P35 was found to bind to GlcNAc-conjugated bovine serum albumin, a neoglycoprotein, as well as to neoglycolipids containing complex-type oligosaccharides derived from glycoproteins, suggesting that P35 recognizes GlcNAc residues such as those found in microbial glycoconjugates and complex-type oligosaccharides. Therefore, P35 represents a new type of GlcNAc-binding lectin with structural and functional similarities to collectins involved in innate immunity.

Thoracoscopic repair of diaphragmatic hernia

A 22-year-old woman presented with left subcostal pain and nausea. A radiograph and a computed tomographic scan of the chest revealed diaphragmatic hernia. Thoracoscopic surgery was performed. The herniated organs were put back into the peritoneal cavity and the hernial hilum was closed with interrupted silk suturing.

Age-related changes of alpha-tocopherol transfer protein expression in rat liver

Developmental changes in expression of alpha-tocopherol transfer protein (alpha-TTP) after birth were investigated using rats with respect to plasma changes of tocopherols. The expression of alpha-TTP in the neonatal rat liver, which was very low immediately after birth, increased steadily during the two weeks of life before weanling and reached the adult level at four weeks. During the suckling period, the plasma ratio of alpha-tocopherol to gamma-tocopherol linearly increased, because plasma alpha-tocopherol which was low immediately after birth, increased rapidly during the period, while gamma-tocopherol remained unchanged. The increase in the ratio seemed to correlate with the developmental expression of alpha-TTP in the liver during this period. The ratio also reached the adult level after four weeks. The expression of alpha-TTP was investigated using primary cultured rat hepatocytes. The expression of alpha-TTP was found to be extremely low after 20h of culture. The decrease in alpha-TTP expression was exacerbated by adding epidermal growth factor to the culture medium and was inhibited by adding dexamethasone. These observations suggest that expression of alpha-TTP may be affected by the state of hepatic differentiation.

Effect of gonadectomy on the development of diabetes mellitus, hypertension, and albuminuria in the rat model

Spontaneously hypertensive rats (SHR) given streptozotocin (STZ) neonatally developed genetic hypertension and overt hyperglycemia after the onset of puberty. In the present study, gonadectomy was performed before puberty in both males and females of this animal model. Orchidectomy suppressed the development of hypertension in vehicle-treated and STZ-treated SHR (systolic blood pressure at 11 weeks of age: 209 +/- 5 mm Hg in the intact vehicle group v 187 +/- 6 mm Hg in the orchidectomized vehicle group, P < .01; 211 +/- 14 mm Hg in the intact STZ group v 182 +/- 4 mm Hg in the orchidectomized STZ group, P < .001). Furthermore, orchidectomy ameliorated the development of overt hyperglycemia in STZ-treated SHR (nonfasting plasma glucose at 12 weeks of age: 22.1 +/- 0.7 mmol/L in the intact group v 16.1 +/- 2.4 mmol/L in the orchidectomized group, P < .05). On the other hand, orchidectomy did not affect glucose tolerance in vehicle-treated SHR, but attenuated the insulin response to an oral glucose load (P < .05). Orchidectomy significantly decreased urinary albumin excretion and kidney weight in both the vehicle and the STZ groups. Ovariectomy significantly increased body weight gain irrespective of STZ treatment. However, ovariectomy had no effect on hypertension, hyperglycemia, albuminuria, or kidney weight in either vehicle or STZ groups. This study demonstrated that gonadectomy had protective effects against development of hypertension, hyperglycemia, and albuminuria in males but not in females. This suggests that sex hormones may be important as a link between diabetes mellitus and hypertension in males.

Stimulation of saphenous afferent nerve produces vasodilatation of the vasa nervorum via an axon reflex-like mechanism in the sciatic nerve of anesthetized rats

The present study was intended to examine the physiological relevance of peptidergic afferent vasodilative fibers in the regulation of blood flow in the vasa nervorum, with special reference to the axon reflex. The response of nerve blood flow (NBF) in the sciatic nerve to electrical stimulation of saphenous nerve afferents was examined using laser Doppler flowmetry in anesthetized rats whose lumbosacral afferents and efferents had been disconnected from the spinal cord. Repetitive electrical stimulation of unmyelinated fibers in the central cut end of the saphenous nerve produced an increase in NBF in the sciatic nerve ipsilateral to the stimulation, independent of changes in mean arterial blood pressure. This increase was abolished by topical application of a calcitonin gene-related peptide (CGRP) receptor antagonist, hCGRP (8-37). In conclusion, NBF in the sciatic nerve is regulated via an axon reflex-like mechanism by unmyelinated afferent CGRP containing vasodilators with collaterals in the saphenous nerve.

Expression of CD10/neutral endopeptidase in normal and malignant tissues of the human stomach and colon

The expression of common acute lymphoblastic leukemia antigen (CALLA; CD10), which is identical to neutral endopeptidase (NEP, EC3.424.11), was examined in the malignant and adjacent noninvaded tissues of the human stomach and colon (n = 27). All of 27 normal and 18 well or moderately differentiated adenocarcioma tissue specimens were positive for monoclonal antibody (mAb) NL-1 against CD10/NEP, whereas the expression level was clearly decreased in all of 9 specimens of poorly differentiated adenocarcinoma. In addition, all of 7 gastric or colorectal carcinoma cell lines tested showed decreased expression of CD10/NEP. Sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis of the crude antigen J5 from the normal colon tissue lysate by mAb J5 detected a single band of approximately 100 kDa that was consistent with that of NALM-6 cells used as a positive control. These findings suggest that CD10/NEP is expressed in normal epithelial cells of the human stomach and colon, whereas the expression level is decreased in the poorly differentiated type of adenocarcinoma.

Cloning and sequence analysis of the pfl gene encoding pyruvate formate-lyase from Streptococcus mutans

We have isolated a sorbitol-negative mutant of Streptococcus mutans GS-5 following random mutagenesis with plasmid pVA891 clone banks. This mutant did not metabolize sorbitol anaerobically but did so aerobically. A 10-kb chromosomal DNA fragment flanking the pVA891 insertion was deleted in this mutant. The corresponding region from the parental strain GS-5 was then recovered by a marker rescue method with Escherichia coli. The pyruvate formate-lyase gene, pfl, was identified within a 3-kb PstI-XbaI fragment located in the middle of the deleted region of the chromosome, and its inactivation in S. mutans produced the same sorbitol-negative phenotype. Nucleotide sequence analysis of the pfl gene revealed a 2.3-kb open reading frame (ORF) preceded by potential ribosome-binding and promoter-like sequences. The ORF specified a putative protein of 775 amino acid residues with a calculated molecular weight of 87,533. The amino acid sequence deduced from the ORF exhibited significant similarity to that of the E. coli pfl gene.

[Two operated cases of synchronous double cancer of the lung and digestive tract in patients over 80 years old and genetical diagnosis]

Synchronous double cancer of the lung and gastrointestinal organ was successfully resected by an one-step approach in two aged patients over 80 years. An 81-year-old man was clinically diagnosed as having a right lung cancer (S3) along with a sigmoid colon cancer. The pathological cell types of these cancers were squamous cell carcinoma and adenocarcinoma respectively. Right upper lobectomy and sigmoidectomy were performed at the same time because he had no risks for the operation. An-80-year-old woman was diagnosed as having a left lung cancer (S8-9) along with a stomach cancer. The cell types of these cancers were both highly differentiated adenocarcinoma. Left lower lobectomy and subtotal gastrectomy were performed at the same time, too. We limited lymph nodes dissection to shorten the operation time and no postoperative complications occurred in both patients. It is suggested that simultaneous operation for double cancer in aged patients can be safely performed in selected cases. In the latter patient, pathological cell type of the lung cancer was similar to that of stomach cancer. So we applied polymerase chain reaction (PCR) for making a diagnosis of double cancer postoperatively, and it was proved that the lung and gastric cancers were different from each other in genetical natures. Application of the genetical technique to clinical field which greatly contribute to making a diagnosis of double cancer is expected.

A case of lymphocutaneous nocardiosis with a review of lymphocutaneous nocardiosis reported in Japan

An 82-year-old Japanese male developed nodules and ulcers along the lymphatics after a fall in the garden of his house resulting in injuries to the dorsum of his left hand which lasted for 3 months. Nocardia brasiliensis was isolated from a nodule, supporting a diagnosis of the lymphocutaneous type of nocardiosis. He had previously developed generalized bone metastasis from prostatic cancer, and his resulting depressed immunity might have played a part in the nocardiosis genesis. Sixteen cases of the lymphocutaneous type of nocardiosis reported in Japan were reviewed.

Timing of cancer chemotherapy based on circadian variations in tumor tissue blood flow

Blood flows of normal tissues (subcutis, liver, kidney cortex, bone marrow) and tumor tissues (SLC) were measured during a daytime period (3-9 HALO) and a nighttime period (15-21 HALO) by the hydrogen clearance technique. Rats were subjected to an artificial light-dark cycle with light from 7 A.M. to 7 P.M. In all normal tissues, there were no significant differences between average tissue blood flows in 2 different time zones, while tumor tissue blood flow increased significantly in the nighttime. Based on this functional characteristic of tumor microcirculation, anti-tumor effects were compared between a group in which ADM was administered at 4 HALO and a group in which it was administered at 16 HALO. The therapeutic effect of ADM on rats administered at 16 HALO was significantly greater, particularly in large tumors, than that on rats administered at 4 HALO. The main reason for this therapeutic improvement may be due to the selective increase in delivery of anti-cancer drugs to tumor tissues brought about by a circadian increase in tumor tissue blood flow.