Guideline-Directed Medical Therapy in Patients With Heart Failure With Reduced Ejection Fraction and Incident Cancer

BACKGROUND

It has been postulated that cancer hampers the delivery of guideline-directed medical therapy (GDMT) for heart failure (HF). However, few data are available in this regard.

METHODS

We performed a retrospective analysis from the HF Outpatient Clinic of the IRCCS Ospedale Policlinico San Martino in Genova, Italy. All HF patients evaluated between 2010 and 2019, with a left ventricular ejection fraction <50% and at least two visits ≥3 months apart with complete information about GDMT were included in the study. We assessed the prescription of GDMT-in particular, beta-blockers (BB), renin-angiotensin system inhibitors (RASi), and mineralocorticoid antagonists (MRA)-at the time of the last HF evaluation and compared it between patients with and without incidental cancer. For those with incidental cancer, we also evaluated modifications of GDMT comparing the HF evaluations before and after cancer diagnosis.

RESULTS

Of 464 HF patients, 39 (8%) had incidental cancer. There were no statistical differences in GDMT between patients with and without incidental cancer at last evaluation. In the year following cancer diagnosis, of 33 patients with incidental cancer on BB, none stopped therapy, but two had a down-titration to a dosage <50%; of 27 patients on RASi, two patients stopped therapy and three had a down-titration to a dosage <50%; of 19 patients on MRA, four stopped therapy.

CONCLUSIONS

Although HF patients with incidental cancer may need to have GDMT down-titrated at the time of cancer diagnosis, this does not appear to significantly hinder the delivery of HF therapies during follow-up.

Coexistence of the Kondo effect and spin glass physics in Fe-doped NbS2

We report the coexistence of the Kondo effect and spin glass behavior in Fe-doped NbS₂ single crystals. The Fe _x NbS₂ shows the resistance minimum and negative magnetoresistance due to the Kondo effect, and exhibits no superconducting behavior at low temperatures. The resistance curve follows a numerical renormalization-group theory using the Kondo temperature [Formula: see text] K for x  =  0.01 as evidence of Kondo effect. Scanning tunneling microscope/spectroscopy (STM/STS) revealed the presence of Fe atoms near sulfur atoms and asymmetric spectra. The magnetic susceptibility exhibits a feature of spin glass. The static critical exponents determined by the universal scaling of the nonlinear part of the susceptibility suggest a three-dimensional Heisenberg spin glass. The doped-Fe atoms in the intra- and inter-layers revealed by the x-ray result can realize the coexistence of the Kondo effect and spin glass.

Switching to an L/N-type calcium channel blocker shows renoprotective effects in patients with chronic kidney disease: the Kyoto Cilnidipine Study

OBJECTIVE

This open-label, randomized controlled trial investigated the effects of cilnidipine, an L/N-type calcium channel blocker (CCB), in patients with chronic kidney disease (CKD).

METHODS

Sixty patients with CKD and well-controlled hypertension being treated with a renin- angiotensin system (RAS) inhibitor and an L-type CCB (L-CCB) were randomly assigned either to switch from the L-CCB to cilnidipine after a 4-week observation period or to continue with L-CCB treatment. Blood pressure, heart rate and renal function were monitored for 12 months. Data were available for analysis from 50 patients: 24 from the cilnidipine group and 26 from the L-CCB group.

RESULTS

Blood pressure was well controlled in both groups. After 12 months, proteinuria and heart rate were significantly decreased in the cilnidipine group, but proteinuria increased and heart rate remained unchanged in the L-CCB group. There was a significant positive correlation between the percentage changes in proteinuria and heart rate.

CONCLUSIONS

Cilnidipine has antihypertensive effects equivalent to those of L-CCBs. In patients with CKD, proteinuria can be decreased by switching from an L-CCB to cilnidipine, thereby improving renal function.

Functional-characterization of developing tumor vascular system and drug delivery (review)

This review summarizes our recent experiments on the process of tumor vascularization and character of tumor vessels. By vitalscopic observation with transparent chambers in rats, we found that the sites where tumor vessels originated were usually terminal portions of terminal arterioles and that an intricate tumor vascular network was constructed from incorporated preexisting vessels and newly formed vessels by three different modes, i.e., sprouting, cross-connecting and splitting. Observation and hydrogen clearance studies showed that tumor blood flow changed remarkably during the development of the tumor vascular network. At an early stage of tumor growth, there were some regions of high flow in the tumor. At an advanced stage, however, there was a rapid increase in low-flow or no-flow areas which were resistant to access of anticancer drugs and oxygen. Angiotensin II-induced hypertension produced a several-fold increase in tumor blood flow without increasing tissue blood flow of normal tissues. These good conditions for drug delivery to tumor tissue are able to enhance therapeutic effects of chemotherapy, irradiation, antibody and photodynamic therapy.

Chiral charge-density waves

We discovered the chirality of charge-density waves (CDW) in 1T-TiSe₂ by using STM and time-domain optical polarimetry. We found that the CDW intensity becomes Ia₁∶Ia₂∶Ia₃ = 1∶0.7 ± 0.1∶0.5 ± 0.1, where Ia(i) (i=1,2,3) is the amplitude of the tunneling current contributed by the CDWs. There were two states, in which the three intensity peaks of the CDW decrease clockwise and anticlockwise. The chirality in CDW results in the threefold symmetry breaking. Macroscopically, twofold symmetry was indeed observed in optical measurement. We propose the new generalized CDW chirality H(CDW) ≡ q₁·(q₂×q₃), where q(i) are the CDW q vectors, which is independent of the symmetry of components. The nonzero H(CDW)-the triple-q vectors do not exist in an identical plane in the reciprocal space-should induce a real-space chirality in CDW system.

Histamine ameliorates anti-glomerular basement membrane antibody-induced glomerulonephritis in rats

Anti-glomerular basement membrane (anti-GBM)-induced glomerulonephritis involves T-helper type 1 (Th1) responses leading to rapid crescent formation. As many inflammatory and immune responses in general are affected by histamine, we examined the effects of histaminergic ligands on immune renal injury in the rat. Female Wistar-Kyoto rats were injected intraperitoneally with an antibody against the GBMs. Histaminergic ligands were then injected twice daily for 5 days after which renal function was assessed by proteinuria. Treatment with histamine led to significant dose-dependent reductions in proteinuria compared to the control antibody-injected group and markedly decreased the number of crescentic glomeruli and macrophage infiltration of the glomeruli. Furthermore, histamine significantly decreased the plasma concentration of interleukin-12, a Th1-type cytokine compared to the antibody-injected control animals. Dimaprit, an H(2)/H(4) agonist, mimicked the effects of histamine on proteinuria and crescent formation. Clozapine, an H(4) agonist, tended to mimic the effects of histamine, whereas an H(1), mepyramine, or an H(2) antagonist, ranitidine, did not reverse the protective effect of histamine. We suggest that histamine may alleviate renal injury in anti-GBM glomerulonephritis by suppressing the immune response.

Renal involvement in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary systemic arteriopathy presenting with migraines, mood disorders, focal neurologic deficits, recurrent ischemic attacks and dementia in young adults. The genesis of this disease relates to missense mutation of the Notch3 gene. We report here a newly identified CADASIL patient and discuss unique vascular lesions observed in the kidney. A 64-year-old female was admitted to our hospital for the investigation of proteinuria, hematuria and progressive neurological abnormalities. Her mother and brother died of cerebral infarction at a relatively young age despite a lack of apparent risk factors for arteriosclerosis. Over the past 4 months before admission, she had suffered from frequent transient ischemic attacks despite appropriate antiplatelet therapy. Blood examination revealed mild renal insufficiency and urinalysis revealed moderate protein excretion and dysmorphic hematuria. Magnetic resonance imaging of the brain revealed multiple infarcts and leukoencephalopathy. Histopathological analysis of the kidney revealed focal segmental mesangial proliferation, the loss and degeneration of arterial medial smooth muscle cells and arterial intimal thickening. Immunofluorescence analysis of glomeruli revealed IgA deposition in the mesangial area. Electron microscope analysis revealed electron-dense deposition also in the mesangial area. In addition, granular osmophilic material (GOM) was observed in the extraglomerular mesangial area and around the vascular smooth muscle cells. Genetic analysis of Notch3 revealed an R141C missense mutation and she was diagnosed with CADASIL complicated with IgA nephropathy. In immunohistological analysis, Notch3 stains were positive in vascular smooth muscle cells of the interlobular arteries and both afferent and efferent arterioles, and weak in the glomerular mesangial area. Antihypertensive treatment using angiotensin II receptor blocker and a low protein diet were initiated, and her urinary protein excretion decreased to 0.2 g/day. However, due to the progression of her neurological abnormalities, she became socially withdrawn. In CADASIL, GOM, abnormal accumulation of Notch3 ectodomain, is thought to induce the degeneration and loss of vascular smooth muscle cells and subsequent intimal thickening. Analysis of our cases provided that these morphological abnormalities were also observed in the CADASIL patient kidney.

Histological analysis on adhesive molecules of renal intravascular large B cell lymphoma treated with CHOP chemotherapy and rituximab

A 48-year-old man was admitted to our hospital for investigation of mild renal dysfunction. A blood examination revealed mild elevation of creatinine level (1.77 mg/dl). Urinary examination revealed mild protein excretion (0.54 g/day) and microhematuria; renal biopsy revealed the focal proliferation of large mononuclear cells with mitosis in glomerular capillaries. According to immunohistochemical analysis, the intravascular lymphomatous cells stained positively with anti-leukocyte common antigen (LCA: CD45) and CD20, indicating a B lymphocyte lineage. In electron microscopy, the glomerular capillary was filled with lymphoma cells and epithelial foot process fusion was noted. Immunohistochemical analysis on adhesive molecules revealed a lack of CD11a expression on lymphoma cells, but positive CD54 expression on endothelial cells. Systemic 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) revealed no abnormal uptake of isotopes. On the basis of these findings, we diagnosed intravascular diffuse large B cell lymphoma localized in the kidney. Despite treatment with rituximab and CHOP (prednisolone, doxorubicin, vincristine, cyclophosphamide) for 3 cycles at 1-month intervals, the renal dysfunction did not change. In histopathological analysis of the second biopsy, lymphoma cells disappeared, but focal segmental glomerulosclerosis and moderate interstitial fibrosis were noted. Electron microscopic findings revealed severe subendothelial edema with mesangial interposition, indicating severe endothelial damage. Epithelial foot process fusion was improved. These pathological analyses let us conclude that a lack of CD11a could be a candidate factor for prevention of the extravasation of lymphoma cells from blood vessels in our patient. We also presumed that the intraglomerular endothelial damage occurred due to chemotherapy-associated cell injury.

Are entrenched characters developmentally constrained? Creating biramous limbs in an insect

Are evolutionarily entrenched phenotypes highly constrained developmentally? We explored this question in the case of the uniramous appendages of fruit flies. We created bi- and polyramous antenna/leg combinations in four different genotypes. Each genotype consisted of two relevant mutations. We suggest that not all entrenched characters are strongly constrained by developmental processes and that there exists sufficient natural genetic variation to alter highly conserved phenotypes.

Vascular morphogenesis and remodeling in a human tumor xenograft: blood vessel formation and growth after ovariectomy and tumor implantation

To determine mechanisms of blood vessel formation and growth in solid tumors, we used a model in which LS174T human colon adenocarcinomas are grown in the isolated ovarian pedicle of nude mice. Reconstruction of 3500 histological serial sections demonstrated that a new vascular network composed of venous-venous loops of varying sizes grows inside the tumor from the wall of the adjacent main vein. Loops elongate and remodel to establish complex loop systems. The mechanisms of loop formation and remodeling correspond to intussusceptive microvascular growth (IMG). In the tissue surrounding the tumor segmentation, another mechanism of IMG is prevalent in venous vessels. Comparison to vascular morphogenesis in the ovariectomized pedicle not only confirms the existence of corresponding mechanisms in both systems, but also reveals numerous sprouts that are superimposed onto loop systems and pathological deviations of loop formation, remodeling, and segmentation in the tumor. These pathological mechanisms interfere with vessel patency that likely cause heterogenous perfusion and hypoxia thus perpetuating angiogenesis. Blood vessel formation based on IMG was also detected in a large thrombus that completely occluded a part of an ovarian artery branch.

Vascular morphogenesis and remodeling in a model of tissue repair: blood vessel formation and growth in the ovarian pedicle after ovariectomy

To investigate mechanisms of vascular morphogenesis in tissue repair, we performed ovariectomy with resection of the corresponding branches of the ovarian vessels in nude mice. This induces a vascular network remodeling response in the healing ovarian pedicle. Reconstruction of 2000 histological serial sections demonstrated that a new vascular network composed of venous-venous loops forms in the wall of the dilated ovarian vein. Preexisting veins of all sizes, including a branch of the main artery, are subjected to segmentation. Loop formation and segmentation are based on intussusceptive microvascular growth. Loop formation is followed by elongation. Loop remodeling occurs also by intussusception and results in the formation of compound loop systems. All loop systems observed were completely patent. Blind-ending sprouts were extremely rare. Anastomoses between the preexisting vessels subjected to segmentation and the loop systems were established to include the newly formed vessels into the preexisting vascular network. The formation of an increasing number of patent loop systems likely decreases hypoxia and subsequently arrests angiogenesis with transformation of the granulation tissue into a scar. Loop formation also occurred inside a large thrombus that occluded a part of the lumen of the main vein.

The Drosophila UBC9 homologue lesswright mediates the disjunction of homologues in meiosis I

BACKGROUND

In Saccharomyces cerevisiae and other organisms, the UBC9 (ubiquitin-conjugating 9) protein modifies the function of many different target proteins through covalent attachment of the ubiquitin-like protein SMT-3/SUMO.

RESULTS

Using a second-site suppression screen of a mutation in the nod locus with a variable meiotic phenotype, we have identified mutations in the Drosophila melanogaster UBC9 homologue, encoded by the gene lesswright (lwr). lwr mutations dominantly suppress the nondisjunction and cytological defects of female meiotic mutations that affect spindle formation. The lwr lethal phenotype is rescued by a Drosophila UBC9/lwr transgene.

CONCLUSIONS

We suggest that LWR mediates the dissociation of heterochromatic regions of homologues at the end of meiotic prophase I. Our model proposes that when there is less LWR protein, homologues remain together longer, allowing for more normal spindle formation in mutant backgrounds and therefore more accurate meiotic chromosome segregation.

[Tumor microcirculation and selective enhancement of drug delivery--clinical applications based on pathophysiological experiments]

Tumor tissue is composed of cancer cells (parenchyma) and tumor vessels (interstitium). Many investigators have pointed out that blood flow in tumors has a very inhomogenous distribution, and that this inhomogeneity in blood flow increases as tumors grew. This would be a certain cause of insufficient drug delivery to tumor tissues. Among the experimental evidence using Yoshida Sarcoma and Ascites Hepatomas, functional differences in microcirculation between tumor and normal tissues were found by Suzuki et al. (1977). Under hypertensive state induced by the continuous infusion of angiotensin II, tumor blood flow increased remarkably, while there was no change or decrease in blood flow in normal tissues such as the brain, bone marrow, liver and kidney. Moreover, the increase in blood flow in tumors was selective, as the mean blood pressure remained at the level of 150 mmHg. Increases were confirmed not only in many growing sites such as in the liver, muscle, subcutis, and even microfoci, but also in various kinds of xenografted human tumors and autochthonous tumors. Augmentation of the anti-tumor effects of angiotensin II-induced hypertension chemotherapy (IHC) for advanced gastric carcinoma was revealed in two randomized controlled trials (RCT-1 & 2) of collaborative study groups in Japan. The response rates were 42.9% vs 10.5% in RCT-1 and 31.3% vs 6.7% in RCT-2. The frequencies of toxicities were not statistically different. In the results of phase II studies from 1978 to 1994 (OPN-1) and 1995 to 1999 (OPN-2) for advanced gastric carcinoma (GC), the response rates were 37.9% and 35.7%. Down staging in which the conclusive stage score was lower than the score of the clinical stage, was observed in 8 out of 94 cases (19%) with primary lesions in total and in 30 patients (63%) receiving reduction surgery after IHC, since 1978. It is very important for exact evaluation after chemotherapy to understand or estimate the pathohistological changes in the tumor and its degenerated or repaired tissues, which present various clinical images. In the present study, the actual administered dose intensity of adriamycin (aDIadm) was 5.9 +/- 2.4 mg/sqm/w, and the ratio of aDIadm to the proposed DIadm of reported FAM/FAP schedules was 0.78 +/- 0.32. IHC with smaller DI could lead to a reduction in the accumulation of toxicities of anti-cancer drugs in the host. In conclusion, IHC might be applied to all kinds of tumors to enhance the chemotherapeutic effects through selective increase of drug delivery to tumors.

Decreased binding sites of angiotensin II in rat LY-80 and AH109A tumour and human gastric cancer using quantitative in vitro autoradiography

BACKGROUND

Under systemic hypertension induced by angiotensin II (AII) infusion, an attenuated vasoconstrictive response to the infusion in tumours was observed and a marked increase in tumour blood flow was observed in comparison with that in normal tissues. The results show a parallel circuit that connects the vascular bed of the pre-existing tissue to that of the tumour. The phenomenon was absent when hypertension was provoked by other vasoconstrictive agents such as norepinephrine or endothelin-1. However, the biological basis for this attenuated vasoconstrictive response to angiotensin II observed in tumours has not been fully elucidated.

METHODS

We assessed this response to characterise the angiotensin II receptor density and affinity in normal and tumour tissues. AH109A and LY80 tumour cell lines were transplanted to the skin in nude rats. Four weeks later, the rats were sacrificed. 125I-[Sar1, Ile8] angiotensin II was used to map its receptors in rat tissues using in vitro computerised autoradiography. Operated human gastric cancer tissues from a 49-year-old and a 66-year-old male patients were also investigated.

RESULTS

The numbers of angiotensin II receptors were markedly reduced in tumour tissues without a change of affinity. The numbers in AII-R in tumours were shown to be mainly AT1 by the marked reduction in radioligand binding achieved by losartan but not by PD123177. The same results were observed in human gastric cancer.

CONCLUSIONS

These results suggest that the decrease in angiotensin II receptors in tumours may explain the haemodynamic effect of angiotensin II-induced hypertension on tumour blood flow. This condition for drug delivery to tumour tissue may play a major role in enhancing the therapeutic effects of chemotherapy.

RNA secondary structure and compensatory evolution

The classic concept of epistatic fitness interactions between genes has been extended to study interactions within gene regions, especially between nucleotides that are important in maintaining pre-mRNA/mRNA secondary structures. It is shown that the majority of linkage disequilibria found within the Drosophila Adh gene are likely to be caused by epistatic selection operating on RNA secondary structures. A recently proposed method of RNA secondary structure prediction based on DNA sequence comparisons is reviewed and applied to several types of RNAs, including tRNA, rRNA, and mRNA. The patterns of covariation in these RNAs are analyzed based on Kimura's compensatory evolution model. The results suggest that this model describes the substitution process in the pairing regions (helices) of RNA secondary structures well when the helices are evolutionarily conserved and thermodynamically stable, but fails in some other cases. Epistatic selection maintaining pre-mRNA/mRNA secondary structures is compared to weak selective forces that determine features such as base composition and synonymous codon usage. The relationships among these forces and their relative strengths are addressed. Finally, our mutagenesis experiments using the Drosophila Adh locus are reviewed. These experiments analyze long-range compensatory interactions between the 5' and 3' ends of Adh mRNA, the different constraints on secondary structures in introns and exons, and the possible role of secondary structures in RNA splicing.

A highly conserved sequence in the 3'-untranslated region of the drosophila Adh gene plays a functional role in Adh expression

Phylogenetic analysis identified a highly conserved eight-base sequence (AAGGCTGA) within the 3'-untranslated region (UTR) of the Drosophila alcohol dehydrogenase gene, Adh. To examine the functional significance of this conserved motif, we performed in vitro deletion mutagenesis on the D. melanogaster Adh gene followed by P-element-mediated germline transformation. Deletion of all or part of the eight-base sequence leads to a twofold increase in in vivo ADH enzymatic activity. The increase in activity is temporally and spatially general and is the result of an underlying increase in Adh transcript. These results indicate that the conserved 3'-UTR motif plays a functional role in the negative regulation of Adh gene expression. The evolutionary significance of our results may be understood in the context of the amino acid change that produces the ADH-F allele and also leads to a twofold increase in ADH activity. While there is compelling evidence that the amino acid replacement has been a target of positive selection, the conservation of the 3'-UTR sequence suggests that it is under strong purifying selection. The selective difference between these two sequence changes, which have similar effects on ADH activity, may be explained by different metabolic costs associated with the increase in activity.

Molecular cloning of a putative cyclic nucleotide-gated ion channel cDNA from Limulus polyphemus

Cyclic nucleotide-gated channels have been proposed to mediate the electrical response to light in the ventral photoreceptor cells of the horseshoe crab, Limulus polyphemus. However, a cyclic nucleotide-gated channel has not been identified from Limulus. We have cloned a putative full-length cyclic nucleotide-gated channel cDNA by screening cDNA libraries constructed from Limulus brain using a probe developed from Limulus ventral eye nerves. The putative full-length cDNA was derived from two overlapping partial cDNA clones. The open reading frame encodes 905 amino acids; the sequence shows 44% identity to that of the alpha subunit of the bovine rod cyclic GMP-gated channel over the region containing the transmembrane domains and the cyclic nucleotide binding domain. This Limulus channel has a novel C-terminal region of approximately 200 amino acids, containing three putative Src homology domain 3 binding motifs and a putative coiled-coil domain. The possibility that this cloned channel is the same as that detected previously in excised patches from the photoreceptive membrane of Limulus ventral photoreceptors is discussed in terms of its sequence and its expression in the ventral eye nerves.

The Drosophila semushi mutation blocks nuclear import of bicoid during embryogenesis

The maternal transcript of the anterior segmentation gene bicoid (bcd) is localized at the anterior pole of the Drosophila egg and translated to form a gradient in the nuclei of the syncytial blastoderm embryo after fertilization [1-3]. The nuclear gradient of Bcd protein - a transcription factor - leads to differential expression of zygotic segmentation genes. The rapid nuclear division during this stage [4] requires that Bcd quickly enters the nuclei after each mitosis using an active nuclear import system. Nuclear transport depends on the asymmetrical distribution of two forms of the small GTPase Ran: Ran-GTP is concentrated in the nucleus and Ran-GDP in the cytoplasm [5-8]. Ran requires RanGTPase-activating protein-1 (RanGAP1) on the cytoplasmic side of nuclear pore complexes to convert Ran-GTP to Ran-GDP. In vitro studies with vertebrate proteins demonstrate that the RanGAP1 associated with the nuclear pore complex is modified with small ubiquitin related modifier-1 (SUMO-1) by a ubiquitin-conjugating enzyme (E2 enzyme) [9-15]. Here, we show that mutation of the Drosophila semushi (semi) gene, which encodes an E2 enzyme, blocks nuclear import of Bcd during early embryogenesis and results in misregulation of the segmentation genes that are Bcd targets. Consequently, semi embryos have multiple defects in anterior segmentation. This study demonstrates that an E2 enzyme is required for nuclear transport during Drosophila embryogenesis.

Long-range base pairing in Drosophila and human mRNA sequences

The potential for long-range base pairing between the 5' and 3' ends of mRNA molecules was examined for 134 Drosophila and 204 human sequences collected from the GenBank database. Each sequence was divided into two parts, a 5' sequence taken from the start of the protein-encoding region and a 3' sequence taken from the end of the transcript. The strongest RNA pairing stem between each pair of 5' and 3' sequences was identified and scored using an alignment program modified to incorporate RNA base pairing. The observed pairing scores were then compared with a random distribution of scores generated by aligning each 5' sequence to random permutations of its corresponding 3' sequence. For both the Drosophila and the human mRNAs, the observed pairing scores were significantly biased toward the upper tail of the random distributions, with 61% of the Drosophila sequences and 64% of the human sequences falling within the upper half of the random distributions. This suggests that a pattern of long-range base pairing may be a common feature of eukaryotic mRNAs. We have also analyzed a subset of Drosophila and human mRNAs which show the greatest potential for long-range pairing. The human pairings appear to be stronger and localized to more specific regions near the ends of the mRNA sequence than those of Drosophila.

Endothelin receptors and angiotensin II receptors in tumor tissue

In cancer chemotherapy, selective enhancement of drug delivery to tumor tissue is essentially important for increase of chemotherapeutic effects. An attenuated vasoconstrictive response to angiotensin II (Ang II) in tumors and a marked increase in tumor blood flow were observed compared with normal tissues during systemic hypertension induced by Ang II infusion. The phenomenon was absent when hypertension was provoked by endothelin-1 (ET-1). We assessed this response to characterize ET receptor and Ang II receptor density and affinity in normal and tumor tissues. The tumor cell line LY80 was transplanted to the skin in nude rats. Four weeks later the rats were sacrificed. [125I] ET-1 and [125I Sar1, Ile8]-Ang II were used to map the receptors for ET and Ang II in rat tissues using computerized in vitro autoradiography. A moderately high density of ET receptors, (ETB > ETA) was found in tumors. The Ang II receptors were markedly reduced in tumor tissues without changes in the affinity. These results suggest that the decrease in Ang II receptors but not ET receptors in tumors may explain the hemodynamic effect of Ang II-induced hypertension and ET-induced hypertension on tumor blood flow.

oroshigane, a new segment polarity gene of Drosophila melanogaster, functions in hedgehog signal transduction

Here we describe a new segment polarity gene of Drosophila melanogaster, oroshigane (oro). Identified as a dominant enhancer of Bar (B), oro is also recessive embryonic lethal, and homozygous oro embryos show variable substitution of naked cuticle with denticles. These patterns are distinctly similar to those of hedgehog (hh) and wingless (wg) embryos, which indicates that oro functions in determining embryonic segment polarity. Evidence that oro function is involved in Hh signal transduction during embryogenesis is provided by its genetic interactions with the segment polarity genes patched (ptc) and fused (fu). Furthermore, ptcIN is a dominant suppressor of the oro embryonic lethal phenotype, suggesting a close and dose-dependent relationship between oro and ptc in Hh signal transduction. oro function is also required in imaginal development. The oroI allele significantly reduces decapentaplegic (dpp), but not hh, expression in the eye imaginal disc. Furthermore, oro enhances the fui wing phenotype in a dominant manner. Based upon the interactions of oro with hh, ptc, and fu, we propose that the oro gene plays important roles in Hh signal transduction.

Site-directed mutations reveal long-range compensatory interactions in the Adh gene of Drosophila melanogaster

Long-range interactions between the 5' and 3' ends of mRNA molecules have been suggested to play a role in the initiation of translation and the regulation of gene expression. To identify such interactions and to study their molecular evolution, we used phylogenetic analysis to generate a model of mRNA higher-order structure in the Adh transcript of Drosophila melanogaster. This model predicts long-range, tertiary contacts between a region of the protein-encoding sequence just downstream of the start codon and a conserved sequence in the 3' untranslated region (UTR). To further examine the proposed structure, site-directed mutations were generated in vitro in a cloned D. melanogaster Adh gene, and the mutant constructs were introduced into the Drosophila germ line through P-element mediated transformation. Transformants were spectrophotometrically assayed for alcohol dehydrogenase activity. Our results indicate that transformants containing a silent mutation near the start of the protein-encoding sequence show an approximately 15% reduction in alcohol dehydrogenase activity relative to wild-type transformants. This activity can be restored to wild-type levels by a second, compensatory mutation in the 3' UTR. These observations are consistent with a higher-order structure model that includes long-range interactions between the 5' and 3' ends of the Adh mRNA. However, our results do not fit the classical compensatory substitution model because the second mutation by itself (in the 3' UTR) did not show a measurable reduction in gene expression.

pO(2) measurement in murine tumors by Eppendorf 'Histograph'

The purpose of this study was to assess the usefulness of the Eppendorf 'Kistograph' as a device for measuring pO(2) in tumor and normal tissues of the laboratory mouse. To determine the appropriate calibration and electrode condition, nitrogen bubbling time was changed, and the current during calibration was recorded. Reproducibility of pO(2) measurements was tested in the series of human xenografts and murine isoplants at different time points or in the same tumor in successive determinations. pO(2) values obtained with the Eppendorf 'Histograph' were compared to those obtained with a manually controlled needle-type electrode manufactured by the Diamond-General Company. The pO(2) values after 9 min of nitrogen bubbling were closer to the expected values than those after 3 min bubbling. The current during nitrogen bubbling in calibration declined following the pO(2) measurement by an amount corresponding to 0.8 mm Hg. Good reproducibility of pO(2) measurement was shown in i) pO(2) values in the same cell line at different time points and ii) pO(2) values in two or three consecutive measurements in related regions within the same tumor. The Eppendorf 'Histograph' and the Diamond-General device showed no significant differences in pO(2) distribution in either subcutaneous tissue or MCaIV tumors. In conclusion, results of the Eppendorf 'Histograph' were consistent and reproducible and were similar to those obtained by the Diamond-General set-up.

Changes in vessel pressure and interstitial fluid pressure of normal subcutis and subcutaneous tumor in rats due to angiotensin II

To elucidate the mechanism of enhancement of transport of anticancer drugs into tumor tissue due to angiotensin II (AII), changes in microvascular pressure (MVP) and interstitial fluid pressure (IFP) due to AII were measured in normal subcutis and subcutaneous tumor in rats. Two different tumor cell lines AH109A and AH272 were used. MVP and IFP were measured using a microocclusion method and a diffusion chamber method, respectively. Insignificant changes in the pressure of normal venous vessels and the IFP of normal subcutis were brought about by AII-induced hypertension. In both AH109A and AH272, the IFP of the same region within the tumor increased with enlargement of tumor volume. The IFP of AH109A tumor (tumor volume = 1.8-2.2 cm3) increased slightly due to AII, but the tumor MVP of AH109A and AH272 increased markedly. Though both tumor IFP and MVP increased significantly due to AII, the increases the hydrostatic pressure difference between tumor vascular and interstitial spaces and leads to enhancement of the efficiency of filtration from tumor vessels to tumor tissue, which is one of the mechanisms of enhancement of drug delivery to tumor tissue due to AII.

The Drosophila tom retrotransposon encodes an envelope protein

The tom transposable element of Drosophila ananassae is mobilized with high frequency in the germ line of females from the ca; px strain, and its insertion results in mutations that show almost exclusively dominant eye phenotypes. tom is a long terminal repeat-containing retrotransposon that encodes three different open reading frames (ORFs). It is expressed in the nurse cells during oogenesis, in the central and peripheral nervous systems during embryonic development, and in the imaginal discs of the larva. tom RNA accumulates in the germarium of ovaries from ca; px females but not in the parental inactive strain, suggesting that this altered pattern of tom expression might be the cause of the high rate of mobilization of this retrotransposon. The specificity of tom-induced eye phenotypes can be explained by the presence of regulatory sequences responsible for expression of tom in the eye imaginal discs of third-instar larvae. These sequences might cause overexpression of adjacent genes affected by tom-induced mutations, resulting in the death of undifferentiated cells located anterior to the morphogenetic furrow. In addition to the full-length RNA, tom is also transcribed into a spliced subgenomic transcript that encodes a protein resulting from the fusion between the amino-terminal region of the first (gag) and the third ORFs. The protein encoded by this RNA shows structural characteristics such as a signal peptide, glycosylation sites, endopeptidase cleavage site, and fusion peptide that are typical of the envelope proteins of retroviruses. Antibodies against tom ORF3 recognize two different proteins present in female ovaries, suggesting that tom might be able to form infective viral particles that could play a role in the horizontal transmission of this retrotransposon.

Effects of intravenous infusion of dopamine on tumor blood flow in rat subcutis

To determine the effects of intravenous administration of dopamine hydrochloride (DA) on tumor blood flow (TBF), we measured the blood flow of normal subcutaneous tissue and subcutaneous tumor (LY-80, a variant of Yoshida sarcoma) in enflurane-anesthetized male Donryu rats using a hydrogen clearance method. Measurements were made before and during intravenous infusion of DA at a rate of 5 micrograms/kg/min, while recording the mean arterial blood pressure of the rats. Under mild hypertension induced by DA, the blood flow of normal subcutis decreased and TBF increased significantly. SCH-23390, an antagonist of the DA1 receptor, inhibited the enhancement of TBF by DA; while domperidone, an antagonist of the DA2 receptor, did not modify the effects of DA. In experimental chemotherapy against the tumor using adriamycin (ADM) 5 mg/kg i.v., only the combination of DA and ADM significantly inhibited the tumor growth. Moreover, DA reduced the weight loss caused by ADM. These results indicate that DA could have a role in increasing TBF and possibly enhance drug delivery to tumors. Moreover, it appears that the DA1 receptor contributes, at least in part, to the enhanced blood flow in rat subcutaneous tumor following DA administration.

[Microvascular mechanisms of change in tumor blood flow elicited by vasopressors]

To elucidate the microvascular mechanisms of change in tumor blood flow due to vasopressors (angiotensin II, epinephrine, methoxamine), we analyzed the site of vascular resistance (VR) increased by each vasopressor. Arteriolar vessels within a transparent rat chamber were classified centripetally (a2-a5) according to Strahler's nomenclature. Vessels that feed into the tumor microcirculation were a2 modified by the tumor (starting vessels). Under angiotensin II (A II)-induced hypertension, the pressure of all arteriolar vessels increased roughly in proportion to the increase in mean arterial blood pressure. The greatest pressure drop and hence the most resistance due to A II occurred across the a2. During epinephrine-induced hypertension, there were major pressure drops between a4 and a3, and between a3 and a2. The amount of contraction of arteriolar vessels due to methoxamine was much smaller than that due to epinephrine, and the pressure increase in a4 and a3 was also small. From the facts described above, we may conclude as follows: A II creates greater vascular resistance of a2 vessels to blood flow and also greater perfusion pressure of a5-a3 vessels, resulting in increased blood inflow into a starting vessel which then becomes a passive vessel. Epinephrine causes an increase in the resistance of a3, a4 and probably upstream from a4 arterioles to blood flow. Thus, tissue blood flow in subcutis and tumor almost always decreases together. The fact that tissue blood flow in normal subcutis and tumor did not change significantly under methoxamine-induced hypertension is probably due to the results that methoxamine had little effects on the vascular resistance of smaller arterioles to blood flow.

Microvascular mechanisms of change in tumor blood flow due to angiotensin II, epinephrine, and methoxamine: a functional morphometric study

To elucidate the microvascular mechanisms of change in tumor blood flow elicited by vasopressors, a functional morphometric study of the s.c. microcirculation within a rat transparent chamber was performed. Arteriolar vessels were classified centripetally (a2-a5) according to Strahler's method. Arteriolar pressure in each segment both under normotension and under hypertension induced by angiotensin II, epinephrine, or methoxamine was measured using a microocclusion technique. Vasoconstriction was estimated by changes in vessel diameters. In addition, tissue blood flow of the subcutis and s.c. tumor (LY80, a variant of Yoshida sarcoma) under the same conditions was measured with the hydrogen clearance method. By comparing the sites of the greatest pressure drop and the vasoconstriction induced by each vasopressor, we assessed the sites of vascular resistance (VR) which showed increases due to these vasopressors. The greatest VR increase elicited by angiotensin II occurred across a2 vessels. On the other hand, the sites of VR increase due to epinephrine were in a3 vessels and larger vessels upstream from a3 arterioles. The VR increase induced by methoxamine was much smaller than that induced by epinephrine. We conclude that the fact that the sites of increased VR differ with each vasopressor is the primary reason that various vasopressors have been found to produce different changes in tumor blood flow.

Mechanisms for appearance of no-flow areas in tumor microvascular bed

In order to elucidate the mechanism for appearance of no-flow areas (areas where tumor blood flow temporarily cease), we directly observed the process of tumor-induced neovascularization and measured pressure change in a feeding vessel (starting vessel) which supplies blood to the tumor vascular network. Total length of tumor vascular network from one starting vessel increased exponentially as the tumor increased in size exponentially. The pressure of the starting vessel increased from approximately 40 cmH2O to 120 cmH2O with enlargement of the tumor size. As soon as the pressure of the starting vessel reached a plateau, however, there was a rapid increase in low-flow or no-flow areas in places within the tumor. We considered that no-flow areas were produced by the imbalance between the pressure elevation of a starting vessel and the enlargement of the vascular network from that vessel.

Circadian variation of tumor blood flow in rat subcutaneous tumors and its alteration by angiotensin II-induced hypertension

Circadian fluctuation in tumor blood flow of the rat subcutaneous tumor was investigated. Tumor tissue blood flows in the daytime zone (10 a.m. to 4 p.m.) and in the nighttime zone (10 p.m. to 4 a.m.) in both the first phase (doubling time of tumor volume = 1.7 days) and the second phase (doubling time of tumor volume = 5.7 days) of growth of the LY80 tumor in rats were measured using the hydrogen gas clearance technique. In the first phase of tumor growth, the tumor blood flow was 20.3 +/- 12.2 ml/min/100 g in the daytime zone (n = 22) and 46.6 +/- 19.3 ml/min/100 g in the nighttime zone (n = 22). In the second phase, tumor blood flow was 9.6 +/- 5.7 ml/min/100 g in the daytime zone (n = 45) and 19.4 +/- 8.2 ml/min/100 g in the nighttime zone (n = 38). Tumor blood flow in the nighttime zone was significantly higher than that in the daytime zone (first phase, P less than 0.001; second phase, P less than 0.001). However, there were no significant differences in the mean arterial blood pressure, tumor size, and body weight of rats between the daytime zone and the nighttime zone. There was also a marked difference in the effect of angiotensin II-induced hypertension on tumor blood flow between the daytime zone and the nighttime zone. These results suggest that circadian fluctuations in tumor blood flow should be carefully considered when developing strategies to maximize the effectiveness of cancer therapy in relation to the flow rate of circulating blood.

Fluctuations in tumor blood flow under normotension and the effect of angiotensin II-induced hypertension

To elucidate the significance of angiotensin II (AII)-induced hypertension chemotherapy, changes of tissue blood flow both in normal subcutis and in tumors (AH109A, LY80) were measured with the hydrogen gas clearance method. A newly-developed anesthetic machine was used to keep the animals' condition constant. Tissue blood flow in normal subcutis and tumors always fluctuated with time under normotension. The nature and the rate of fluctuation in tumor blood flow were almost identical in two different types of tumors. However, the fluctuation of blood flow in tumor and that in normal subcutis were almost always inversely related when blood flows in these different tissues were measured simultaneously, i.e., when tissue blood flow in normal subcutis decreased, tumor blood flow increased, and vice versa. The findings supported the idea that the connection mode between the tumor vascular bed and normal vascular bed is a parallel circuit. Vascular resistance in the normal vascular bed under AII-induced hypertension seemed to be greater than that under normotension, because the AII-increased tumor blood flow always exceeded the maximum tumor blood flow under normotension. Due to the fluctuations of tumor blood flow, no-flow or low-flow areas, resistant to delivery of anti-cancer drugs, moved sporadically within the tumor under the normotensive condition. However, good conditions for drug delivery to tumor tissue were induced by AII-induced hypertension.

Comparison of the effects of intravenously bolus-administered endothelin-1 and infused angiotensin II on the subcutaneous tumor blood flow in anesthetized rats

To evaluate the effects of endothelin-1 (ET-1) on tumor blood flow, the authors measured the mean arterial blood pressure (MABP) of enflurane-anesthetized male Donryu rats and the tissue blood flow of subcutaneously implanted tumor (Yoshida rat ascites hepatoma LY-80) by using a hydrogen clearance method. The tumor blood flow was evaluated in terms of the ratio to the maximum blood flow, which was defined as the largest flow in the same position during successive measurements. After bolus intravenous administration of ET-1 (1.0 nmol/kg), MABP reached approximately 140 mmHg (at 5-30 min), diminishing gradually to the baseline level over 2 h. The tumor blood flow increased from 36.7 +/- 20.6 to 59.5 +/- 30.2% (n = 32, P less than 0.001, at 2 min), returning to the baseline level at 10 min. On the other hand, at 2 min after the beginning of continuous intravenous infusion of [Asp1, Ile5]-angiotensin II (AII; the dose was determined by a blood pressure control system for keeping MABP at approximately 150 mmHg, consequently 0.26 micrograms/kg/min on the average), the tumor blood flow increased from 42.3 +/- 21.6 to 76.4 +/- 22.6% (n = 32, P less than 0.001), which was significantly larger than the flow after ET-1. The results indicate that hypertension induced by systemic ET-1 injection is less effective than hypertension induced by continuous systemic AII infusion in increasing tumor blood flow; AII is probably a suitable agent as a safe and effective enhancer of tumor blood flow. Moreover, ET-1 appears to constrict arterial vessels in the microcirculation time-dependently, while AII constricts probably only normal peripheral arterioles.

Retrotransposon-induced overexpression of a homeobox gene causes defects in eye morphogenesis in Drosophila

Insertion of the tom transposable element into various Drosophila ananassae genes results in dominant phenotypes that affect eye morphology. One of these genes encoded by the Om(1D) locus was isolated by transposon tagging. The Om(1D) gene encodes a 2.7 kb transcript that is expressed in every stage of development. The deduced Om(1D) protein is 606 amino acids long and contains two glutamine/histidine, two alanine-rich and one histidine/proline repeats, as well as a homeodomain located near the carboxy terminus. Tom-induced alleles of Om(1D) show a 1.7-fold increased accumulation of Om(1D) RNA in whole individuals during late larval--early pupal stages of development, whereas expression of this transcript is 7-fold higher in the eye--antenna imaginal disc of mutant versus wild-type flies. D. melanogaster flies transformed with the Om(1D) coding region under the control of the hsp70 promoter display an eye phenotype similar to that of Om(1D) when expression of the homeobox protein encoded by the chimeric gene is induced by temperature elevation at the end of the third instar period. These results suggest that the eye-specific mutant phenotype caused by the insertion of the tom retrotransposon in the Om(1D) locus may be a consequence of the tissue-specific induction of the expression of this gene by sequences present in the transposable element.

Characterization of heterogeneous distribution of tumor blood flow in the rat

Angioarchitectures of ascites hepatoma AH109A and Sato lung carcinoma (SLC) were quantitatively compared by measuring the following morphometric parameters: vascular density, vascular length, distance between tissues and their nearest blood vessel, and total length of microvascular network per unit area. When the vascular networks in these two types of tumors were compared in the initial stage, the morphological parameters were almost identical. Correlations between tumor size and the number of starting vessels and between enlargement of the tumor and the ensuing increase in pressure of the starting vessel were also evaluated with a microcomputer and an apparatus for measuring microvascular pressure. The total length of tumor vascular network to which one starting vessel supplied blood increased exponentially as the tumor increased in size exponentially. There was a positive correlation between tumor size and the number of starting vessels. The range of the blood supply from one starting vessel was evidently limited. The pressure of the starting vessel increased with enlargement of the tumor size. As soon as the pressure of the starting vessel reached a plateau, however, there was a rapid increase in low-flow or no-flow areas in regions within the tumor. From the results obtained, we consider that low-flow or no-flow areas, resistant to delivery of anticancer drugs, inevitably appear with the progression of tumor growth.

[Development of the angioarchitecture and microcirculatory characteristics in rat tumor]

Using a rat transparent chamber and a device for measurement of microvascular pressure, we observed tumor vascularization process in vivo and measured the daily change in pressure of a "starting vessel" which supplies blood to the tumor vascular network. Results were summarized as follows: (1) The position from which tumor vessels originated was usually the terminal portion of a terminal arteriole (starting vessel). The frequency with which new capillaries originated from vein and venule was very low. (2) Pressure of a starting vessel increased from 30-40 cm H2O (22-30 mmHg) to 120-130 cm H2O (88-96 mmHg) with enlargement of the tumor vascular network. As soon as pressure of a starting vessel reached a plateau, no-flow vessels appeared in places within a tumor. (3) Pressure of a starting vessel was elevated by angiotensin II. In turn, the elevated pressure of a starting vessel brought about a marked increase in tumor blood flow, resulting in the blood flow in no-flow vessels.

In vivo analysis of tumor vascularization in the rat

By using transparent chambers in rats, we have directly observed tumor-induced neovascularization in the early stage and the formation of intricate networks in Yoshida rat ascites hepatoma AH109A and Sato lung carcinoma at high magnification. We counted branching point numbers per unit area in the microvascular network with and without tumors in order to clarify the sites from which new vascular sprouts originate. Branching point number per unit area in normal tissue was 13.6 +/- 7.4/0.1 mm2 in the field near a terminal arteriole, and 12.9 +/- 7.3/0.1 mm2 in the field distant from a terminal arteriole. There was no significant difference between these two fields in the normal vascular network. On the other hand, in the tumor vascular network, the branching point number in the field near a terminal arteriole was 50.4 +/- 12.6/0.1 mm2, and 30.1 +/- 11.5/0.1 mm2 in the field distant from a terminal arteriole. The difference is highly significant (P less than 0.001). The frequency with which new capillaries originated from veins and venules was very low. We concluded from these results that the position from which tumor vessels originated was usually the terminal portion of a terminal arteriole.

[The effects of angiotensin II and other noradrenergic vasoconstrictors on the blood flow in Yoshida rat ascites hepatoma AH 109 A at same electrode position]

The differing effects of angiotensin II (AT II) and five other vasoactive agents on the tissue blood flow in Yoshida rat ascites hepatoma AH 109 A were studied at the same electrode position by a hydrogen clearance method. The elevation of blood pressure by AT II resulted in a 3.4-fold increases in the tumor blood flow. However, when AT II was reinfused, it resulted in only 2.1, 2.2, 2.3, 1.9 and 2.4-fold increases, respectively, after infusion of methoxamine, norepinephrine, metaraminol, epinephrine, and phenylephrine. A pronounced reduction and further reducing tendency in the tumor blood flow were found after administration of norepinephrine and epinephrine. In addition, metaraminol, phenylephrine, and methoxamine did not change significantly the blood flow of the tumor. The results of this present blood flow study further suggest that AT II acts more peripherally in the host vascular bed from which newly growing tumor vessels bud than other vasoconstrictors do.