Nude mouse metastatic models of human stomach cancer constructed using orthotopic implantation of histologically intact tissue

Nude mice have been used to develop s.c. growing human stomach tumors, but these rarely metastasize. Recently, I. J. Fidler and others have developed orthotopic implantation metastatic models using cell suspensions which are inoculated into the corresponding organ of nude mice from which the tumor cells were originally derived in the human. However, recent work has indicated that disaggregated cell suspensions may not always express their full metastatic potential. In this light, we have recently developed an orthotopic implant model utilizing intact tissue such as that obtained directly from surgery. This approach has yielded high take rates and frequent metastases in colon cancer, bladder cancer, lung cancer, pancreatic cancer, and prostate cancer. We report here the application of this intact tissue orthotopic implant technique to stomach cancer resulting in the formation of metastases in 100% of the mice with extensive primary growth to the regional lymph nodes, liver, and lung. In contrast, when cell suspensions were used to inject stomach cancer cells at the same site, metastases occurred in only 6.7% of the mice with local tumor formation, emphasizing the importance of using intact tissue to allow full expression of metastatic potential. Injuring the serosa similar to that occurring in intact tissue transplantation did not increase the metastatic rate after orthotopic injection of cell suspensions of stomach tumor cells. This intact tissue orthotopic implantation model should allow development of new treatment modalities and further study of the biology of human stomach cancer.

Characteristics of lidocaine block of sodium channels in single human atrial cells

Although lidocaine block of cardiac Na+ current (INa) has been extensively studied in animal tissues, very little is known about its actions on human cardiac INa. We studied the effects of lidocaine (0.01-10 mM) on human atrial INa in single myocytes using whole-cell patch-clamp techniques. The dose-response relationship for lidocaine block at a low frequency (0.2 Hz, "tonic" block) indicated that lidocaine blocked Na+ channels by one-to-one binding with an apparent Kd of 291 microM. Lidocaine (200 microM) shifted the steady-state INa availability curve by -11 mV, but did not change the slope factor (n = 5). Lidocaine also induced use-dependent block that increased directly with increases in drug concentration (0.01-1 mM) and pulse duration (3-100 msec) and inversely with interpulse interval (2-0.33 sec). The time constant for onset of lidocaine (200 microM) block of INa displayed both a fast (tau f = 3.6 +/- 0.4 msec) and a slow (tau s = 168 +/- 21 msec) exponential component (n = 10). In addition, lidocaine slowed the rate of INa recovery after a 1-sec conditioning pulse to -20 mV, recovery was biexponential at a low drug concentration (20 microM), but had only a single slow phase at a high drug concentration (200 microM). These characteristics of lidocaine block suggest that lidocaine binds to both inactivated and activated Na+ channels in human atrial cells and that use-dependent block of INa by lidocaine is dependent on drug concentration, interpulse interval and pulse duration, findings similar to those reported for other mammalian species. The similarity of these results to those obtained from atrial as well as ventricular cells from other species suggests that some source other than differential drug action on atrial and ventricular INa underlies differential drug efficacy against supraventricular and ventricular dysrhythmias.

Early resection of primary orthotopically-growing human colon tumor in nude mouse prevents liver metastasis: further evidence for patient-like hematogenous metastatic route

We have developed an orthotopic transplant model of human cancer to immunodeficient mice utilizing microsurgical techniques with intact tissue. The resulting transplanted human tumors grow locally and metastasize in a clinical-like pattern. However, there has been no definitive evidence in colon cancer that the human tumors metastasize via hematogenous route in nude mice. In the present study, in order to obtain definitive evidence of physiological spread of the human tumors, the primary tumors were resected 10 days after the initial orthotopic transplantation to the nude mice. The resection prevented metastases from forming, demonstrating that metastases of the human colon cancers occur after 10 days and by physiological and non-seeding mechanisms in the transplanted nude mice.

Interferon beta increases antitumor activity of 5-fluorouracil against human colon carcinoma cells in vitro and in vivo

The modulating effect of human fibroblast-derived interferon beta (IFN-beta) on the antitumor effect of 5-fluorouracil (5-FU) against human colon carcinoma cells in vitro and in vivo was investigated. The 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide (MTT) assay was carried out in vitro using the cultured human colon cancer cell line C-1. IFN-beta at concentrations of 50, 500, 5,000 and 50,000 IU/ml was added to the cultured tumor cells with or without 5-FU at concentrations of 10, 50 and 500 micrograms/ml. The antitumor activity of 5-FU with or without IFN-beta was assessed using Co-4, a human colon carcinoma xenograft in nude mice, with reference to thymidylate synthetase inhibition. IFN-beta was administered subcutaneously daily for 14 days at doses of 6,000, 60,000 and 600,000 IU/mouse. The combined antitumor effect with 5-FU was evaluated by simultaneous intraperitoneal administration of 5-FU at doses of 10 and 20 mg/kg daily for 10 days. The antitumor activity of IFN-beta alone increased in a dose-dependent manner against Co-4 in nude mice, whereas its antitumor activity in vitro against C-1 was limited. The synergistic effect of 5-FU and IFN-beta was observed both in vitro and in vivo, and the in vivo synergism was obtained without any enhancement of thymidylate synthetase inhibition or side effects in terms of death rate and body weight loss. These results suggest that the mechanism of the combined effect of 5-FU and IFN-beta is not related to enhancement of thymidylate synthetase inhibition or the host immune system, since human fibroblastoid IFN-beta is species-specific to humans. The clinical usefulness of this combination method for the treatment of advanced colorectal carcinoma is expected.

Molecular cloning of a chloride channel that is regulated by dehydration and expressed predominantly in kidney medulla

Complementary DNA encoding a rat kidney chloride channel (CIC-K1) was isolated by a polymerase chain reaction (PCR) cloning strategy. We designed degenerate primers, based on the regions where previously cloned chloride channels (CIC-0, -1, and -2) possess significant amino acid identity, and performed reverse transcription PCR with whole kidney mRNA. The 686-amino acid protein encoded by CIC-K1 is about 40% identical to the previously cloned chloride channels and has a similar hydropathy profile. Expression of CIC-K1 in Xenopus oocytes induced Cl- currents that activate instantaneously upon hyperpolarization and depolarization, and displayed a slightly outwardly rectifying current-voltage relationship. The message for CIC-K1 was 2.4 kilobases and was found predominantly in kidney, especially in the inner medulla. Reverse transcription PCR technique using micro-dissected nephron segments revealed that the main site of expression in kidney was the thin ascending limb of Henle's loop, which has the highest Cl- permeability among the nephron segments and is thought to be involved in a counter-current system for urine concentration in the inner medulla. The abundance of CIC-K1 mRNA in kidney increased about 4-fold as rats became dehydrated by deprivation of water for 5 days. The site of expression and the regulation by dehydration suggest that CIC-K1 function may be important in urinary concentrating mechanisms.

Orthotopic transplantation of histologically intact clinical specimens of stomach cancer to nude mice: correlation of metastatic sites in mouse and individual patient donors

Fresh surgical specimens derived from 36 patients with advanced stomach cancer were orthotopically transplanted in nude mice using histologically intact tissue. Twenty of 36 patient tumors gave rise to locally growing tumors in the mice. All 20 patients whose stomach tumors resulted in local growth in the nude mice had clinical lymph-node involvement, whereas 8 of the other 16 patients whose tumors were rejected had lymph-node involvement. There was a statistical correlation (p < 0.01) between local tumor growth in nude mice and clinical lymph-node involvement. Of the 20 cases resulting in local growth in the nude mice, 5 had clinical liver metastases and all 5 cases resulted in liver metastases in the nude mice. Of the 20 cases, 6 had clinical peritoneal involvement of their tumor, and of these 5 resulted in peritoneal metastasis in the nude mice. There were statistical correlations (p < 0.01) for both liver metastases and peritoneal involvement between patients and mice. These results indicate that, after orthotopic transplantation of histologically intact stomach cancers from patients to nude mice, the subsequent metastatic behavior of the tumors in the mice closely correlated with the course of the tumors in the patients.

Modulation of the effect of glibenclamide on KATP channels by ATP and ADP

The inside-out configuration of the patch-clamp technique was used to study the effect of glibenclamide on the ATP-sensitive K+ channel current in isolated guinea-pig ventricular myocytes. The inhibitory effect of glibenclamide was tested in the bath solution containing two different concentrations of ATP (100 microM and 200 microM). It was found that the effect of the drug on the KATP current was stronger in the presence of the higher concentration of ATP. The blocking effect of glibenclamide on the channels was weaker if, in addition to ATP, ADP was applied in the intracellular solution. Similarly, the inhibitory effect of the drug was not pronounced for the channels reactivated by ADP after run-down. As application of the drug in the presence and absence of Mg2+ did not show different effects on the channel inhibition, we concluded that the effect of glibenclamide may not depend on the phosphorylation of the channel protein. These results suggest that in addition of the previously described effect of ADP, ATP also has some modulatory effect on inhibition of the KATP channel by glibenclamide.

Completely thrombosed giant fusiform aneurysm in a young patient--case report

A completely thrombosed giant fusiform aneurysm of the peripheral anterior cerebral artery occurred in a 16-year-old female, with a familial and personal history of vascular headache for 4 or 5 years. She was admitted in a drowsy state with severe headache. Computed tomography revealed subarachnoid hemorrhage and intracerebral hemorrhage as a mottled and ring-like high-density area in the left paramedian frontal lobe not enhanced postcontrast. Left carotid angiography demonstrated an avascular mass and a 5 cm defect in the A3 portion of the anterior cerebral artery. The rupture of the giant fusiform aneurysm was confirmed intraoperatively.

High frequency of etoposide (VP-16)-related secondary leukemia in children with non-Hodgkin's lymphoma

PATIENTS AND METHODS

We report patients who were treated for non-Hodgkin's lymphoma (NHL) or Ki-1 antigen-positive (Ki-1) lymphoma with a T-8801 protocol that included etoposide (VP-16) and behenoylcytosine arabinoside.

RESULTS

Secondary acute myeloid leukemia (AML) developed in 5 of 38 NHL and Ki-1 lymphoma patients, and the cumulative risk at 4 years was 18.4%. The median time from the initiation of the chemotherapy to the development of AML was 21 months (range, 13-30). Four patients had a FAB M5 morphology, and one had FAB M2. In four of five examined cases, chromosomal alterations involving the long arm of chromosome 11 were demonstrated at the time of development of AML. None of the 46 NHL patients who we treated with another protocol (B-8801), using significantly higher cumulative doses of VP-16 than in the case of the patients with T-8801 and a different schedule of VP-16 administration, developed secondary AML.

CONCLUSIONS

The risk of secondary AML possibly related to the use of VP-16 given twice weekly.

Antagonism of central pressor response to angiotensin II by alpha-human atrial natriuretic polypeptide at the preoptic area and posterior hypothalamus in rats

Effects of alpha-human atrial natriuretic polypeptides (alpha-hANP) on pressor responses to angiotensin II (AII) were assessed at the preoptic area, posterior hypothalamus and central amygdaloid nucleus (ACE) in spontaneously hypertensive (SHR) and control normotensive Wistar-Kyoto (WKY) rats. Angiotensin II, administered intracerebroventricularly, at a dose of 100 ng produced a marked pressor response in hypertensive, as well as in normotensive rats and the response was potentiated in hypertensive rats. The response was antagonized in a dose-dependent manner by administration of alpha-hANP into the preoptic area and posterior hypothalamus but not to the amygdaloid nucleus. The antagonism was more marked in hypertensive than in normotensive rats. Angiotensin II, when injected directly to the preoptic area at a small dose of 10 ng similarly evoked a marked pressor response, which was augmented in hypertensive rats. This response was also antagonized by coadministration of alpha-hANP to the preoptic area in hypertensive but not in normotensive rats. The results suggest that the antagonistic relationship between ANP and AII exists at the preoptic area and posterior hypothalamus, probably implying that the activity of the ANP and AII systems in brain play a role in centrally controlling the cardiovascular system and is altered at these areas in genetically hypertensive rats.

Colorimetric chemosensitivity testing using sulforhodamine B

A colorimetric chemosensitivity test was investigated using sulforhodamine B (SRB), which stains protein synthesized by cells, as an end-point marker. Four cultured cell lines, 9 human tumor xenografts serially transplanted into nude mice, and 14 fresh surgical specimens were subjected to this assay. The optimal conditions for the assay were 3-5 x 10(4) cells per well in a 96-microplate, an SRB concentration of 4%, and an incubation time of more than 10 minutes. When mitomycin C, doxorubicin, cisplatin, and 5-fluorouracil were assessed by the SRB assay, the concentration-effect curves revealed a sharp slope between plateaux at low and high concentrations, suggesting that this assay has an excellent sensitivity which can assess the effect of drugs as "all or none." Although this high sensitivity resulted in good reproducibility of the assay for cultured cell lines, the predictive rate of the SRB assay for the chemosensitivity of human tumor xenografts in vivo was limited to 63.9%. As a result, this SRB assay is thought to be useful for evaluating the chemosensitivity of cultured cells as all or none, since it can assess directly cellular protein synthesis, which is one of the most important parameters of cell renewal, with excellent sensitivity.

Hyperthermia induced by the dopamine D1 receptor agonist SK&F38393 in combination with the dopamine D2 receptor agonist talipexole in the rat

The present experiments were performed to investigate the effects of dopamine D1 receptor agonists given alone or in combination with dopamine D2 receptor agonists on body temperature in rats. The selective dopamine D1 receptor agonist, 1-phenyl-2,3,4,5-tetrahydro-(1H)-3-benzazepine-7,8-diol (SK&F38393), produced hyperthermia. However, the dopamine D2 receptor agonist, B-HT 920 (talipexole), and the newly synthesized dopamine D2 receptor agonist, (S)-2-amino-4,5,6,7-tetrahydro-6-propylamino-benzothiazole (SND 919), did not change the temperature. Interestingly, the SK&F38393-induced hyperthermia was enhanced by talipexole and SND 919. The drastic hyperthermia induced by combined administration of dopamine D1 and D2 receptor agonists was blocked by either the dopamine D1 receptor antagonist, SCH23390, or the dopamine D2 receptor antagonist, spiperone. On the other hand, treatment with prazosin, yohimbine, propranolol, scopolamine, or methysergide failed to affect the marked hyperthermia. The present results suggest that a functional link between dopamine D1 and D2 receptors may be synergistic in the regulation of body temperature and that concurrent stimulation of both dopamine D1 and D2 receptors thereby produces marked hyperthermia in the rat.

Experimental cancer chemotherapy using a liver metastatic model of human colon cancer transplanted into the spleen of severe combined immunodeficient mice

We have developed a liver metastatic model of human colon cancer using severe combined immunodeficient (SCID) mice. Liver metastases were observed in all the SCID mice on day 28 after intrasplenic injection with 5 x 10(6) dissociated tumor cells of COL-2-JCK, a human colon cancer strain serially transplanted in nude mice. When this model was applied for chemotherapeutic experiments, 5-fluorouracil (5-FU) demonstrated significant antitumor effects in preventing liver metastases, whereas the efficacy of 5-FU was limited in the currently used sc-ip chemosensitivity assay in nude mice. When the human LDH-5 isozyme was evaluated in the homogenized metastatic liver tissue of SCID mice, a good correlation was obtained between the liver tumor weights and LDH-5 isozyme, suggesting that it could be a promising quantitative indicator for metastases. This model would be useful for further studies on the treatment of liver metastases of colon cancer.

Low-threshold motor effects produced by stimulation of the facial area of the fifth somatosensory cortex in the cat

The motor effective sites of the fifth somatosensory cortex (SV) in the cat were mapped in detail by using unit recording and intracortical microstimulation (ICMS) techniques. The motor effective sites for facial muscle contraction were identified using stimulus currents of less than 30 microA. Of the 257 effective sites detected, 49% were activated by stimulus currents of less than 20 microA and of these, 51% responded to stimulus currents of less than 10 microA. ICMS within the facial area of the SV neuron produced contralateral eye-blinking, the lowest threshold current for which was 2 microA and ICMS within the SV neurons produced whisker movements, the minimum threshold current for which was 4 microA. Furthermore, stimulation of some SV neurons at a threshold current as low as 4 microA produced whisker movements and some responded to both visual and cutaneous stimuli. Ablation of areas 6a beta, 3a, SII, SIII and the motor cortex did not eliminate or reduce the low-threshold responses elicited by this weak stimulation of the SV. These motor effective areas receive input from the contralateral cutaneous of the surrounding muscle motor effective region. Our results suggest that the described effect is independent of motor effective areas.

Possible transsynaptic cholinergic neuromodulation by ATP released from ileal longitudinal muscles of guinea pigs

The effects of alpha, beta-methylene ATP (alpha, beta-mATP) and beta, gamma-methylene ATP (beta, gamma-mATP) on endogenous acetylcholine (ACh) release evoked by electrical nerve stimulation were evaluated in guinea-pig ileal longitudinal muscles. Release of ACh was measured with an HPLC-electrochemical detector system and release of ATP by luciferin-luciferase assay. Electrically evoked endogenous ACh release was reduced by both alpha, beta-mATP and beta, gamma-mATP at concentrations of 3 and 30 microM. The inhibitory effect of alpha, beta-mATP (30 microM) on ACh release was not detectable in the presence of theophylline (100 microM), a P1-purinoceptor antagonist, that itself enhanced ATP release. When exogenous ATP (0.1 microM) was added to the bath in which the ileal segment was suspended, it was rapidly metabolized, presumably by ecto-ATPase, and disappeared from the medium within 15 min. At 30 microM, alpha, beta-mATP induced ATP release in a suramin-sensitive but Ca(2+)- and atropine-insensitive manner, suggesting P2-receptor-mediated release of ATP from the smooth muscle. We conclude from these findings that alpha, beta-mATP and, probably, also beta, gamma-mATP, do not reduce ACh release by direct stimulation of presynaptic P1-purinoceptors, and that endogenous ATP released postjunctionally by these ATP analogs is decomposed metabolically to adenosine in the synapse and this adenosine triggers P1-purinoceptor sensitive neuromodulation of cholinergic transmission.

MRI of intradural-extramedullary spinal neurinomas and meningiomas

The magnetic resonance images of 16 patients with intradural-extramedullary spinal tumors, consisting of 11 neurinomas and five meningiomas were reviewed. The neurinomas appeared hypointense compared to the spinal cord on unenhanced T1-weighted images (T1WI) in nine of 11 patients, and hyperintense on T2-weighted images (T2WI) in nine of 11 patients. Neural foraminal extension was present in two cases. All 10 neurinomas were markedly enhanced; six of them exhibited ring-like enhancement on Gadolinium-DTPA (Gd-DTPA)-enhanced T1WI. The meningiomas appeared isointense on unenhanced T1WI in four of five patients and on T2WI in three of four patients. Three meningiomas showed moderate homogeneous contrast enhancement after the intravenous administration of Gd-DTPA. It is concluded that careful scrutiny of magnetic resonance images facilitates the differential diagnosis of spinal neurinomas and meningiomas.

Antibodies to human cytomegalovirus 65-kilodalton Fc binding protein in rheumatoid arthritis: idiotypic mimicry hypothesis of rheumatoid factor production

We previously reported that rheumatoid factors (RFs) might bear the internal image of Fc gamma-binding proteins (FcBPs) of herpes family viruses, suggesting the possibility that some RFs may be produced as antiidiotypic antibodies to anti-viral FcBP antibodies. Since human cytomegalovirus (HCMV) has been implicated in the pathogenesis of RA, we made an attempt to detect antibodies to 65 KD major HCMV FcBP in sera and synovial fluid from patients with RA. Western blotting was performed using HCMV-infected MRC-5 cell lysate as the antigen. Eleven of 23 patients with RA possessed strong serum antibodies to HCMV-65 KD protein, whereas such antibodies were found in only 2 of 23 normal controls. In the synovial fluid, 10 of 19 RA patients showed anti-HCMV 65 KD reactivity. Pepsin-digested IgG retained anti-65 KD reactivity, indicating that false-positive reaction due to the presence of IgG Fc portion and/or RF was unlikely. 65 KD protein was shown to be different from human heat shock proteins (hsps) using monoclonal antibodies against human hsps. Patients' IgG F(ab')2 also reacted with the 65 KD protein of purified HCMV virion itself. These results support the possibility that some RFs could be produced as antiidiotypic antibodies to anti-viral FcBP antibodies.

Antitumor activity and interleukin-1 induction by tannins

The relationships between structures, antitumor activities and interleukin-1 (IL-1) induction by fifteen tannins were studies. When tannins (10 mg/kg) were intraperitoneally injected into mice once, 4 days before intraperitoneal inoculation of S-180 cells, tellimagrandin II, rugosin A, hirtellin B, oenothein B and oenothein A, which have only tellimagrandins I or II units in their molecules, had significant antitumor activity. Although casuarictin and its related tannins were ineffective, agrimonin, which is a dimer, had a strong effect, as previously reported. On the other hand, monomeric ellagitannins such as tellimagrandins I and II, rugosin A and casuarictin also increased IL-1 beta production from human peripheral macrophages in vitro by 2-fold over the non-stimulated basal production and oligomeric ellagitannins with strong antitumor activity more potently stimulated the IL-1 beta induction. Other tannins having no antitumor activity induced less IL-beta. This study indicates that oligomeric ellagitannins, which consist of tellimagrandin I or II, casuarictin or their related structure units, have antitumor activity and induce IL-1 beta.

Growth of human tumor xenografts in nude mice and mice with severe combined immunodeficiency (SCID)

Twenty-three fresh tumor specimens obtained at surgery and 5 serially transferable human tumor xenografts were implanted subcutaneously into nude mice and mice with severe combined immunodeficiency (SCID) to compare the take rates of the fresh surgical specimens and the growth rates of the transferable strains. The overall take rates were 65% for the SCID mice and 60% for the nude mice, without any significant difference, although colon carcinoma seemed to have higher acceptance in the SCID mice with a take rate of 6/8. All the serially transferable strains were successfully accepted in the SCID mice, their growth rates being essentially identical to those in the nude mice. These results indicate that the SCID mouse can be used as a human tumor xenograft-mouse system as well as the nude mouse.

Antitumor activity of oenothein B, a unique macrocyclic ellagitannin

The antitumor effect of oenothein B, a macrocyclic ellagitannin from Oenothera erythrosepala Bordas, on rodent tumors was studied. Oenothein B exhibited a strong antitumor activity against MM2 ascites tumors upon intraperitoneal administration to the mice before or after the tumor inoculation. The tannin also inhibited the growth of Meth-A solid type tumor in mice. This antitumor effect of the tannin could not be attributed to its direct cytotoxic action on tumor cells, because the cytotoxicity was very weak in the presence of serum protein. When oenothein B was injected into the peritoneal cavity of mice, peritoneal exudate cells, including cytostatic macrophages, were induced. Furthermore, in the in vitro treatment of macrophages from mice and humans, the tannin stimulated release of an interleukin 1 (IL-1)-like activity and IL-1 beta from the cells. These results suggest that oenothein B exerts its antitumor effect through potentiation of the host-immune defense via activation of macrophages.

Implication of ATP released from atrial, but not papillary, muscle segments of guinea pig by isoproterenol and forskolin

Effects of isoproterenol and forskolin, which increases intracellular cyclic AMP, on contraction and ATP release in atrial and papillary muscles of guinea pig were evaluated. In the electrically driven-left atrial muscle segments, isoproterenol and forskolin at 0.1 microM produced an ATP release coupled with a positive inotropic effect, the values of net ATP release at 5 min after these drugs being 5.20 +/- 0.59 and 5.37 +/- 0.55 nmoles/g wet weight, respectively. The forskolin evoked-ATP release was unaffected by prazosin plus propranolol or by guanethidine, implying that ATP is released from non-neuronal origin. In contrast, in papillary muscle segments, the test cardiotonics did not elicit any ATP release despite producing contractile response similar to that in atrial preparations. However, there is no difference in ectoATPase activities of both tissues. Adenosine added exogenously inhibited electrically evoked-contraction of the atrium, but not that of the papillary, although inhibitions by verapamil of the contractions were approximately equal in these preparations. These findings suggest that cardiotonics such as isoproterenol produce a liberation of ATP from auricle muscles, but not from ventricle muscles, and that the liberated ATP may mainly be catabolized to adenosine by ectoenzymes and the resultant nucleoside may serve as a functional modulator through stimulation of pre or postsynaptic A1-receptors.