Myosin II activation promotes neurite retraction during the action of Rho and Rho-kinase

BACKGROUND

The Rho small GTPase regulates myosin II activity through the phosphorylation of the myosin light chain (MLC) by activating Rho-kinase, which is a target of Rho. Several lines of evidence point to an important role of Rho in the action of lysophosphatidic acid (LPA) and thrombin in provoking neurite retraction in N1E-115 neuroblastoma cells.

RESULTS

Here we examined whether Rho-kinase and myosin II are involved in neurite retraction in N1E-115 cells. We showed that the expression of constitutively active forms of Rho-kinase induced neurite retraction in NIE-115 cells and MLC phosphorylation in NIH 3T3 cells, whereas the expression of dominant negative forms of Rho-kinase inhibited the LPA-induced neurite retraction in N1E-115 cells and the serum-induced MLC phosphorylation in NIH 3T3 cells. The expression of mutant MLCT18D,S19D (substitution of Thr and Ser by Asp), which is known to lead to the activation of myosin ATPase and a conformational change of myosin II when reconstituted with myosin heavy chains in vitro, also promoted neurite retraction.

CONCLUSION

These results indicate that Rho-kinase is involved in the LPA-induced neurite retraction downstream of Rho, and that myosin II activation promotes neurite retraction downstream of Rho and Rho-kinase.

Increased levels of GM2 ganglioside in fibroblasts from a patient with juvenile Niemann-Pick disease type C

A 15-year-old boy was suffering from splenomegaly and a 10-year history of a neurologic disorder that included mental retardation, vertical supranuclear gaze palsy, dysarthria, ataxia, and dystonia. Bone marrow aspirates revealed foamy cells with storage materials which were positive with filipin staining. Cultured skin fibroblasts derived from the patient showed moderate loss of sphingomyelinase activity and the impairment of cholesterol esterification. The characteristic clinical presentations and typical histochemical findings of this patient met the diagnostic criteria of Niemann-Pick disease type C (NPC). In the fibroblasts from the patient, there was an accumulation of GM2 ganglioside around their cytoplasms. Increased levels of glycolipids. including GM2 ganglioside are reported in the cerebral cortex of NPC, but not in the fibroblasts. The fibroblasts derived from NPC may reflect the abnormal metabolism of glycolipids in the central nervous system of NPC.

Expression and localization of inducible nitric oxide synthase in the rat ovary: a possible involvement of nitric oxide in the follicular development

In the present study, using Northern blot analysis, we demonstrated that the level of iNOS mRNA in the ovary of immature rats decreased after 6 h of pregnant mare serum gonadotropin administration and recovered gradually up to the untreated level 48 h after the administration. Both in situ hybridization and immunohistochemistry revealed that iNOS mRNA and protein was predominantly localized in granulosa cells in most of immature follicles, but not in mature follicles with an antrum, which was a consistent finding regardless of gonadotropin treatment. Furthermore, we found that cultured granulosa cells had the ability to express iNOS mRNA in the presence of cytokines such as tumor necrosis factor-alpha, interleukin-1 beta and interferon-gamma, which are inherently detectable in the ovary. These results raise the possibility that locally produced NO synthesized by iNOS may be involved in the developmental status of ovarian follicles in concert with gonadotropin.

Interleukin-6 produced by pancreatic carcinoma cells enhances humoral immune responses against tumor cells: a possible event in tumor regression

Production of interleukin-6 (IL-6) by human pancreatic carcinoma cells inversely correlates with potentials for blood-borne metastasis to the liver in nude mice. IL-6 cDNA was transfected to PCI-43, one of our cultured pancreatic carcinoma cell lines that does not produce IL-6 and generates numerous metastases to the liver. An IL-6 high-producer clone (PCI-43h) generated few metastases; IL-6 production thus has a direct effect on metastasis, whereas other transfectants (PCI-43l and PCI-43n), which are IL-6 low-, and IL-6 non-producers, respectively, did generate metastases. Tumor-reactive IgG, which mediated antibody-dependent cellular cytotoxicity (ADCC) in vitro, was detected in sera from recipient nude mice inoculated with PCI-43h but not in sera from mice given PCI-43l, PCI-43n or parent PCI-43. Tumor-reactive IgM was detected in sera from all mice, irrespective of inoculated PCI-43 species, with a slight augmentation being noted in PCI-43h-inoculated nude mice. Severe combined immunodeficiency (SCID) beige mice were then used as recipients for PCI-43 species, and tumorigeneity was examined by s.c. inoculation of a suboptimal number of PCI-43 transfectants (1 x 10(6)/0.1 ml). Only PCI-43h formed palpable masses in SCID beige mice, whereas it first grew to be palpable but subsequently became not palpable in nude mice, thereby revealing a dual action of tumor-derived IL-6. Thus, tumor-derived IL-6 confers growth promotion in SCID beige mice, while the same cytokine exhibits anti-tumorigenic functions, presumably through humoral immune responses, in nude mice.

Induction of heme oxygenase-1 in toxic renal injury: mercuric chloride-induced acute renal failure in rat

It is known that mercuric chloride (HgCl2) is a nephrotoxicant. When HgCl2 (1 mg/kg body weight) was intraperitoneally injected into rats, acute renal failure was induced. Histological changes in the kidneys were exclusively observed in the proximal tubules and the severe necrosis was found as early as 24 h after HgCl2 injection. The heme oxygenase-1 (HO-1) mRNA was strongly and promptly induced at about 2.5 h, the earliest time examined and abruptly decreased after the injection. Whereas the time course of HO-1 protein level was delayed as compared with that of HO-1 mRNA level. The levels of HO-1 mRNA and protein similarly increased with dose-dependent manner. The localization of HO-1 protein was restricted to the tubule cells. These findings suggest the potential involvement of HO-1 induction in the response to HgCl2-induced acute renal injury.

Effects of accelerated carbon-ions on growth inhibition of transplantable human esophageal cancer in nude mice

We have studied the effectiveness of 290 MeV/u carbon-ion (C-) beams (linear energy transfer (LET) of 70 keV/mm) and 200 kVp X-rays on tumor growth inhibition as an in vivo model for radiotherapy of cancer. We measured the size of tumor growth of transplantable human esophageal cancer in nude mice after radiation with C-beams and compared this with X-rays as the control. A significant inhibition of tumor growth was observed by C-beams as compared with X-rays. The relative biological effectiveness (RBE) of C-beams against X-rays was 2.02. Histopathological studies showed that C-beams at 20 Gy induced prominent necrosis in the central region and multinucleate giant cells and inflammatory cells in peripheral regions of the tumor, whereas X-rays at 20 Gy induced only mild necrosis. The high RBE of C-beams obtained in this study provides in vivo evidence that C-beams are more effective than conventional X-rays for radiotherapy of cancer.

Refractive-index patterning of tellurite glass surfaces by laser spot heating

A dot pattern of a refractive-index change was formed by spot heating with laser-beam irradiation on sodium tellurite glasses. The 15Na2O.85TeO2 (mol. %) glass doped with 2 mol. % of CoO was irradiated by a green light-beam spot (532 nm) approximately 800 microm in diameter from the second-harmonic generator of a Q-switched pulsed YAG laser. The map of the refractive index of the glass was determined with an He-Ne laser beam by a scanning ellipsometric technique at a resolution of 100 microm x 50 microm, indicating that the spots possessing a refractive index lower by approximately 0.05 were formed at the region irradiated by the laser beam.

Human beta-migrating very low density lipoprotein induces foam cell formation in human mesangial cells

To elucidate the mechanism of foam cell formation in the mesangial region of a kidney observed in a familial type III hyperlipoproteinemic patient presenting with diabetes mellitus and nephrotic syndrome, we have examined, in the present study, the effect of human beta-VLDL (apo E2/E2) on foam cell formation in human mesangial cells, since an increase in beta-VLDL is a characteristic feature of this patient. Human beta-VLDL (apo E2/E2) induced foam cell formation in human mesangial cells. The binding of [125I]LDL to human mesangial cells was inhibited completely by both LDL and beta-VLDL. On the other hand, the binding of [125I]beta-VLDL was completely inhibited by beta-VLDL, but partially by LDL. The LDL receptor, but not the VLDL receptor was down-regulated by accumulation of cholesteryl esters. These results suggest that human beta-VLDL (apo E2/E2)-induced foam cell formation in mesangial cells is mediated through both the LDL receptor pathway and the beta-VLDL specific pathway, in which the VLDL receptor is one of the candidates.

[Characteristic situation on prevention of nosocomial infection in the hospital for the severely multi-disabled--experiences in care and treatment of 4 kinds of viral hepatitis]

We experienced Hepatitis A, B, C and fulminant hepatitis due to Herpes simplex virus type 1 (HSV-1) in our hospital for the severely multi-disabled (SMD) who had both severe motor and intellectual disabilities, and some of whom might be further complicated by blindness and/or deafness. In this hospital, 100 SMDs are hospitalized. Case 1: The disabled, 25 year old male, was transmitted Hepatitis A from a nurse. Case 2: The disabled, 60 year old female carrier of Hepatitis B virus (HBV) who has been cared for more than 10 years. Case 3: The disabled, 46 year old male carrier of Hepatitis C virus (HCV) (RNA type 3), has been cared for more than 4 years. Case 4: The disabled, 39 year old male, had a fever of 39 degrees C for 9 days and suddenly died. He was diagnosed as fulminant hepatitis due to HSV-1 by necropsy. The hospitals for SMD are characteristic in prevention of nosocomial infections; 1) The disabled infected is not aware of the fact that he or she is the source of infection and that the other disabled living with him or her are in risk of infection, because of their severe mental condition. 2) All of the disabled need complete or incomplete helps for activities of daily life (ADL), so that the disabled who is the carrier of some pathogen constantly gives risk of infection to staffs, including medical staffs (doctor, nurse and therapist), psychologist and helpers by bloody secretion from wounds, saliva, urine, feces as well as menstrual blood. 3) If a carrier of some pathogen is hospitalized, the staffs should serve under risk of infection involving blood-mediated infectious disease for many years, because SMDs are permitted lifelong stay in the hospitals for SMD, which also play a role of care house or institution, by public expense in Japan. In case of an outbreak of Hepatitis A, nosocomial infection ended in the original case (a nurse), another nurse and a case of the disabled by general treatment and care against communicable diseases of the digestive organs. In care of HBV and HCV carriers, an ordinary program to prevent nosocomial infection has been practiced in our hospital more strictly than in conventional hospital. HBV vaccine is injected to staffs caring the HB carriers who are negative on HBs antibody. Thus, during more than 10 years of care of HBV carrier and more than 4 years of care of HCV carrier, nosocomial infection has never been experienced clinically as well as serologically in our hospital. However, we have often been faced by difficulty to guarantee QOL (quality of life) of the carriers, because carrier states of HBV or HCV have been long-lasting and they have been occasionally and inevitably separated physically and/or psychologically in order to prevent nosocomial infection. In case 4, it was suspected that previously latently infected HSV-1 would be activated by another viral infection which had elicited fever for 9 days before death. The patient had neither history nor sign or symptom of immunodeficiency and had never been given drugs known as to be immunosuppressive as side effect.

Diagnosis of visceral pleural invasion in resected lung cancer using a jet stream of saline solution

BACKGROUND

Visceral pleural invasion by the tumor is an important prognostic factor in patients undergoing resection for lung cancer. We developed a method to detect more accurately the presence of visceral pleural invasion in resected lung cancer.

METHODS

The surface of the visceral pleura over 90 resected peripheral tumors was irrigated twice with a jet stream of saline solution using a 20-mL syringe with a 21-gauge needle, and then the fluid, which contained desquamated cells, was collected for cytologic analysis. When cancer cells were found in the collected fluid, the tumor was judged to have invaded the visceral pleura.

RESULTS

Thirty-eight (42%) resected tumors were identified as having visceral pleural invasion either by our new method or by pathologic examination. Twenty-four cases were detected by the jet stream of saline method alone, 5 by pathologic examination alone, and 9 by both techniques. The sensitivity and accuracy of the two approaches in the diagnosis of visceral pleural invasion were 87% and 94%, respectively, for our new method, and 37% and 73%, respectively, for pathologic examination (p < 0.0001). Furthermore, among 38 patients who had a tumor demonstrating visceral pleural invasion, 5 (13%) and 9 (24%) patients, respectively, had cancer cells in the pleural effusion and intrapleural lavage fluid.

CONCLUSIONS

Our findings suggest that our method is useful in detecting cancer invasion of the visceral pleura, which is considered one of the causes of malignant effusion.

Reperfusion therapy for acute vertebrobasilar occlusion

SUMMARY

We reviewed retrospectively our experience in treating 10 patients with acute vertebrobasilar occlusion. Nine patients were treated with interventional reperfusion therapy and the remaining one patient with top of the basilar embolism was treated conservatively because of deep coma and decerebrate rigidity with severely reduced cerebral blood flow (CBF) in the brain stem. Among 9 patients with reperfusion therapy, 8 patients underwent intra-arterial thrombolytic therapy and the other one patient had direct percutaneous transluminal angioplasty (PTA). Eight patients had basilar artery occlusion, 1 patient treated with direct PTA had bilateral intracranial vertebral artery occlusion and the other patient had left posterior cerebral artery occlusion presumably preceding top of the basilar embolism. In 4 of 10 patients, residual CBF was evaluated by single photon emission computed tomograpy (SPECT). Successful recanalization with clinical improvement was achieved in 6 of 9 patients (66.7%) treated with reperfusion therapy. In patients with progression or fluctuation of incomplete brain stem syndrome, SPECT revealed preserved residual CBF and successful recanalization with clinical improvement was achieved by interventional reperfusion therapy. On the other hand, in patients with persistent deep coma and decerebrate rigidity, SPECT revealed marked reduction of residual CBF in the brain stem and recanalization could not improve clinical outcome. Preoperative SPECT may be useful to make a decision whether rep er fusion therapy should be performed or not in case of vertebrobasilar occlusion.

Effects of ethyl-all-cis-5,8,11,14,17-icosapentaenoate (EPA-E), pravastatin and their combination on serum lipids and intimal thickening of cuff-sheathed carotid artery in rabbits

The anti-arteriosclerotic effects of ethyl all-cis-5, 8, 11, 14, 17-icosapentaenoate (EPA-E), pravastatin and their combination in cuff-treated rabbits were investigated. EPA-E at 600 mg/kg, pravastatin at 50 mg/kg or their combination was orally administered once daily for 5 weeks, and each of the animals was sheathed with a cuff on the carotid artery 2 weeks after the beginning of drug administration. EPA-E, pravastatin and their combination significantly reduced serum total cholesterol compared to the control group. EPA-E also potently reduced serum triglyceride, while pravastatin only slightly reduced it. The combination of these two agents had the most potent effect on the level of serum triglyceride. Serum phospholipids were also reduced by these treatments in a similar fashion. At the end of treatment, diffuse intimal thickening was observed in the cuff-covered region in all animals in the control group, and the intima/media area ratio in this group was 0.293 +/- 0.038. Treatment with EPA-E alone tended to prevent the intimal thickening, and the intima/media area ratio was 0.209 +/- 0.058 (p = 0.094). This ratio was 0.287 +/- 0.048 (p = 0.902) when pravastatin was administered alone, indicating that it had no significant effect on intimal thickening. The ratio was 0.175 +/- 0.041 (p = 0.042) when both EPA-E and pravastatin were administered, indicating that this combination had a significant inhibitory effect on intimal thickening in the cuff-sheathed region. These findings suggest that combined treatment with EPA-E and pravastatin is more effective than respective monotherapies in lowering serum lipids and/or preventing an intimal thickening as events of atherogenesis.

Effects of vitamin E deficiency and glutathione depletion on stress protein heme oxygenase 1 mRNA expression in rat liver and kidney

Heme oxygenase 1 (HO-1) is a stress protein and has been suggested to provide defense mechanisms against agents that may induce oxidative injury. Vitamin E (VE) is considered to function as an important cellular antioxidant. Rats were fed a VE-deficient (0E) or a VE-sufficient (10E) diet for 6 weeks and then were intraperitoneally administered buthionine sulfoximine (BSO), a glutathione (GSH)-depleting reagent. Whereas HO-1 mRNA levels were undetectable in untreated 0E and 10E rat livers, BSO administration induced HO-1 mRNA expression in both 0E and 10E rat livers. High levels of HO-1 mRNA expression were observed in particular in BSO-treated 0E rat livers. The time-course of changes in HO-1 mRNA expression in 0E rat liver after BSO administration showed that HO-1 mRNA expression was transiently induced at 2.5 hr after BSO treatment, the earliest time examined. In addition, to determine whether VE deficiency and GSH depletion affect the expression of HO-1 mRNA in other tissues, we also examined the time-course of HO-1 mRNA expression in BSO-treated 0E rat kidney. The expression pattern of HO-1 mRNA in the kidney was very similar to that in the liver, and the peak was also observed at about 2.5 hr after BSO administration. Interestingly, histologic assessment of liver and kidney showed that VE deficiency and GSH depletion induced injury in the kidney, but not in the liver.

Regulation and immunohistochemical analysis of stress protein heme oxygenase-1 in rat kidney with myoglobinuric acute renal failure

Intramuscular injection of hypertonic glycerol solution to rats results in acute renal injury. In this model, the proximal tubules are characteristically damaged. After glycerol injection renal glutathione (GSH) levels drastically decreased. On the other hand, stress protein heme oxygenase-1 (HO-1) was induced. When N-acetyl cysteine was administered to rats before 1 h glycerol injection, renal function was obviously improved. In this condition, the renal GSH content were sustained in the normal levels and HO-1 protein levels were decreased compared with those of glycerol-treated rats. Induction of HO-1 was accompanied by reduced renal GSH content. In addition, to investigate whether the location of HO-1 protein induced by glycerol injection is restricted to injured region or not in the kidney, we determined the localization of HO-1 protein using immunohistochemical staining. HO-1 protein was identified in the epithelia of the distal tubules, Henle's loop and collecting ducts, but not in the injured proximal tubules.

Genes coding for enterotoxins and verotoxins in porcine Escherichia coli strains belonging to different O:K:H serotypes: relationship with toxic phenotypes

Seventy-four E. coli strains isolated from piglets with diarrhea or edema disease in Spain were serotyped and examined for production of heat-labile (LT) and heat-stable (ST) enterotoxins (LT-I, LT-II, STaH, STaP, and STb) and verotoxins (VT1, VT2, and VT2v = VTe) by phenotypic (Vero cell assay and infant mouse test) and genotypic (colony hybridization and PCR) methods. In general, an excellent correlation was found between the results obtained with a PCR approach and those determined with biological assays. DNA probes used in the hybridization also showed a very good agreement with phenotypic results, with the exception of a VT1 probe that initially produced 10 false-positive reactions. The gene coding for STb (58 strains) was the most prevalent gene detected by PCR, followed by those coding for STa (46 strains), LT (19 strains), VT2v (11 strains), and VT1 (1 strain). Apparently, in Spain three seropathotypes are predominant: (i) O149:K91:H10 K88+ LT-I+ STb+, (ii) O141:K85ab:H- P987+ STaP+, and (iii) O138:K81:H14 or H- STaP+ VT2v+. We conclude that PCR is a fast, specific, and practical method for the identification of enterotoxin and VT genes in clinical and epidemiological studies.

Intraoperative intrapleural hypotonic cisplatin treatment for carcinomatous pleuritis

BACKGROUND AND OBJECTIVES

We recently developed a new intraoperative intrapleural hypotonic cisplatin treatment for carcinomatous pleuritis found at thoracotomy in non-small cell lung cancer patients. In the present study, the efficacy and adverse events of this treatment as well as the pharmacokinetics of cisplatin in the blood after the treatment were evaluated.

PATIENTS AND METHODS

Twenty-one patients received the treatment for 15 minutes after completing the intrathoracic surgical procedures. The total and free platinum levels in the blood of five patients were then measured. As a control, 29 patients without such treatment were reviewed retrospectively.

RESULTS

The survival rates in the treatment and non-treatment groups were similar. The pleural disease free survival of the treated patients was, however, significantly higher than that of the non-treated patients. Such pleural disease as effusion and the growth of the pleural disseminated tumors only appeared in three of the 21 (14%) treated patients while 26 of 29 (90%) non-treated patients had clinically detected pleural disease. The blood platinum levels after the treatment were extremely low and such low levels probably induced no systemic adverse events after the treatment. The only adverse event of this treatment was an increase in the postoperative drainage volume.

CONCLUSIONS

These observations seem to suggest that intraoperative intrapleural hypotonic cisplatin treatment for carcinomatous pleuritis found at thoracotomy can, at least, delay the appearance of the pleural disease without any adverse events.

Beta-very low density lipoprotein induces triglyceride accumulation through receptor mediated endocytotic pathway in 3T3-L1 adipocytes

To elucidate the mechanism of triglyceride (TG) accumulation in adipocytes induced by TG-rich lipoproteins, we examined the effect of beta-very low density lipoprotein (beta-VLDL) on TG accumulation in 3T3-L1 adipocytes. Beta-VLDL did not induce TG accumulation in 3T3-L1 preadipocytes but in 3T3-L1 adipocytes. TG accumulation was significantly inhibited by cytochalasin B, an inhibitor of receptor mediated endocytosis. In contrast, cytochalasin B did not inhibit free fatty acid induced TG accumulation in adipocytes. The binding of [125I]beta-VLDL to preadipocytes was inhibited completely by both beta-VLDL and LDL. In sharp contrast, the binding of [125I]beta-VLDL to adipocytes was inhibited completely by beta-VLDL, but partially by LDL. The VLDL receptor mRNA was only expressed in adipocytes. These results suggest that beta-VLDL induced TG accumulation in adipocytes may be mediated through the VLDL receptor pathway.

[High-resolution CT of otosclerosis]

High-resolution CT (HRCT) scans of thirty-two patients (60 ears) with the clinical diagnosis of fenestral otosclerosis were evaluated retrospectively. HRCT was performed with 1-mm-thick targeted sections and 1-mm (36 ears) or 0.5-mm (10 ears) intervals in the semiaxial projection. Seven patients (14 ears) underwent helical scanning with a 1-mm slice thickness and 1-mm/sec table speed. Forty-five ears (75%) were found to have one or more otospongiotic or otosclerotic foci on HRCT. In most instances (30 ears), the otospongiotic foci were found in the region of the fissula ante fenestram. No significant correlations between CT findings and air conduction threshold were observed. We found a significant relationship between lesions of the labrinthine capsule and sensorineural hearing loss. We conclude that HRCT is a valuable modality for diagnosing otosclerosis, especially when otospongiotic focus is detected.

Cytoskeletal rearrangements and transcriptional activation of c-fos serum response element by Rho-kinase

The small GTPase Rho is implicated in cytoskeletal rearrangements including stress fiber and focal adhesion formation and in the transcriptional activation of c-fos serum response element. In vitro, Rho-kinase, which is activated by Rho, phosphorylates not only myosin light chain (MLC) (thereby activating myosin ATPase) but also myosin phosphatase, thus inactivating myosin phosphatase. Rho-kinase is involved in the formation of stress fibers and focal adhesions in fibroblasts. Here we show that the expression of constitutively active Rho-kinase increased the level of MLC phosphorylation. The activity of Rho-kinase was necessary for maintaining the vinculin-containing focal adhesions, whereas organized actin stress fibers were not necessary for this. The microinjection of constitutively active Rho-kinase into fibroblasts induced the formation of focal adhesions to some extent under the conditions where organized actin stress fibers were disrupted. The expression of constitutively active Rho-kinase also stimulated the transcriptional activity of c-fos serum response element. These results suggest that Rho-kinase has distinct roles in divergent pathways downstream of Rho, which include MLC phosphorylation leading to stress fiber formation, focal adhesion formation, and gene expression.

Receptors on chicken erythrocytes for F42 fimbriae of Escherichia coli isolated from pigs

Haemagglutination of purified F42 fimbriae was found to be inhibited by N-acetyl-galactosamine. Purified F42 fimbrial adhesin reacted with distinct membrane components from chicken erythrocytes (35, 37 and 40 kDa) in immunoblot analysis, suggesting that the binding occurred to proteins or glycoproteins.

Immunohistochemical analysis of heme oxygenase-I in rat liver after ischemia

Total hepatic ischemia was induced by clamping the hepatic artery, portal vein, and bile duct. After 15 min hepatic ischemia, we examined a time course of the changes in the steady-state levels of heme oxygenase-1 (HO-1) mRNA and protein in the livers. The levels of HO-1 mRNA was transiently induced and peaked at 4 h after the start of reperfusion. In addition, a pattern of the time course of HO-1 protein levels was similar to that of HO-1 mRNA levels. Immunohistochemical analysis clearly showed that the localization of HO-1 protein induced by hepatic ischemia was restricted to the hepatocytes in the pericentral vein.

Antitumor effects and toxicities of carboxymethylpullulan-peptide-doxorubicin conjugates

In vivo antitumor effects of the conjugates of doxorubicin (DXR) with carboxymethylpullulan (CMPul) through tetrapeptide spacers were compared with those of DXR against tumor-bearing rats. CMPul-DXR conjugates bound through Gly-Gly-Phe-Gly and Gly-Phe-Gly-Gly spacers were found to be more potent than DXR after a single intravenous injection in rats bearing Walker 256 carcinosarcoma. These conjugates were also more effective than DXR in rats bearing Yoshida sarcoma. However, CMPul-DXR conjugate bound through Gly-Gly-Gly-Gly was less effective against Walker 256-bearing rats than DXR. Body weight loss of CMPul-DXR conjugates in rats, on the other hand, was less than that of DXR at a DXR dose of 10 mg/kg. Lethal doses of CMPul-DXR conjugates in CDF1 mice were about 3-times higher than that of DXR. These data suggest that the therapeutic index of CMPul-DXR conjugates bound through appropriate peptide spacers was increased more than that of DXR. However, CMPul-DXR conjugates tested were all less effective than DXR against Walker 256 cells in vitro. Also, 125I-labeled CMPul-DXR conjugate accumulated much less in the cells than 14C-DXR.

Measurement of spinal cord blood flow by an inhalation method and intraarterial injection of hydrogen gas

PURPOSE

This study was performed to determine spinal cord blood flow using the H2 clearance method.

METHODS

In 12 dogs we measured blood flow determined by hydrogen clearance techniques (BF) in both gray and white matter by spinal cord puncture, and compared the results with BF measured by a catheter inserted intrathecally to avoid spinal cord injury. We studied direct intraarterial and intravenous injection of hydrogen in addition to the inhalation method because hydrogen is an explosive gas.

RESULTS

BF measured intrathecally with catheters adherent to either the ventral or the dorsal funiculus did not differ significantly from that of the gray matter. BF measured with a catheter inserted into the epidural space was about one fourth of the BF measured intrathecally. Values measured by the intraarterial injection method did not differ significantly from those obtained by the inhalation method.

CONCLUSIONS

BF measured with a catheter inserted intrathecally reflects blood flow in the gray matter of the spinal cord. Using intraarterial injection of H2, BF was safety and accurately measured while avoiding the risk of explosion.