Autocrine loop through cholecystokinin-B/gastrin receptors involved in growth of human leukemia cells

The cholecystokinin (CCK)-B/gastrin receptor binds two brain-gut hormones, CCK and gastrin, with high affinities. These peptides have a trophic effect on gastrointestinal cells expressing the receptor in vivo as well as in vitro. Recently, this receptor mRNA was reported to be expressed in immunocytes localized in the lamina propria of normal rat stomach mucosa. Here, we studied the receptor expression in human hematopoietic cells in order to determine whether they play a role in cell growth. The CCK-B/gastrin receptor mRNA was detectable in the polymorphonuclear (PMN) cells but not in the mononuclear cells of normal peripheral white blood cells by reverse transcription-polymerase chain reaction. The receptor transcript was, however, expressed in human leukemia cell lines (14 of 18 cell lines tested) derived from not only myeloid, but also T- and B- lymphoid lineages. The CCK-B/gastrin receptors on several leukemia cell lines were shown to be biologically active by demonstrating ligand-dependent cell proliferation in serum-deprived medium. Interestingly, a human CCK-B/gastrin receptor specific antagonist, YM022, but not its stereotype isoform, selectively inhibited the DNA synthesis of THP-1, MOLT-16, MOLT-14, and CCRF-CEM in the absence of exogenous peptide ligands. Further investigation revealed that these leukemia cell lines and normal PMN cells also expressed gastrin mRNA. These results suggest that growth of human leukemia cells is promoted by an autocrine mechanism through the CCK-B/gastrin receptors.

Purification and characterization of bitiscetin, a novel von Willebrand factor modulator protein from Bitis arietans snake venom

We have screened 20 snake venoms and purified a novel snake venom protein, named bitiscetin, from Bitis arietans venom that specifically binds to human von Willebrand factor (vWF) and induces platelet agglutination. Bitiscetin showed a heterodimeric structure composed of disulfide-linked alpha (16kDa) and beta (13kDa) subunits on SDS-PAGE and showed a basic nature with pI value of 9.1, in contrast to botrocetin (pI 4.6), a vWF modulator isolated from another snake (Bothrops jararaca) venom. Bitiscetin-induced platelet agglutination was dependent on vWF and platelet membrane glycoprotein (GP) Ib, but not on Ca2+ and GPIIb/IIIa. vWF bound to bitiscetin but not to botrocetin electroblotted to a PVDF membrane after SDS-PAGE and this binding was diminished after reduction of disulfide bonds of bitiscetin. Bitiscetin did not cross-react to anti-botrocetin monoclonal antibodies. These results suggest that bitiscetin directly interacts with vWF and requires the protein conformation for its interaction as well as botrocetin, but its interaction manner with vWF appears to be different from that of botrocetin.

Status of the coagulation and fibrinolytic systems in ovarian hyperstimulation syndrome

OBJECTIVE

To elucidate characteristic changes of plasma hemostatic markers in ovarian hyperstimulation syndrome (OHSS) cycles.

DESIGN

Prospective study.

SETTING

The IVF-ET program of the Department of Obstetrics and Gynecology, The University of Akita, School of Medicine.

PATIENTS

Forty cycles of 40 IVF patients, including 12 cycles in which a severe form of OHSS occurred.

INTERVENTIONS

Blood samples were taken during IVF treatment to determine the levels of blood markers that reflect activation of the coagulation and fibrinolytic systems.

MAIN OUTCOME MEASURES

Thrombin-antithrombin III complexes, plasmin-alpha 2 antiplasmin complexes, and other hemostatic markers related to the coagulation and fibrinolytic system activation.

RESULTS

In the OHSS cycles, the levels of thrombin-antithrombin III and plasmin-alpha 2 antiplasmin complexes in the plasma began to rise within a few days after hCG administration and demonstrated significantly higher levels during the midluteal phase. In OHSS cycles with pregnancy, elevation of these markers continued for > or = 3 weeks after the onset of disease. There were some characteristic changes in OHSS cycles in other hemostatic markers, such as a decrease in the levels of antithrombin III and prekallikrein and shortened activated partial thromboplastin time.

CONCLUSION

These data demonstrate the status of the coagulation and fibrinolytic systems in OHSS cycles and provide insight into the mechanism of activation in the hemostatic system.

[Treatment results for unselected patients with acute myelogenous leukemia. During a 10-year period, August 1984 to July 1994]

In order to analyse the clinical characteristics and outcome in acute myelogenous leukemia, 129 consecutive adult patients admitted to our hospital over a 10-year period, from August 1984 to July 1994, were studied. Their median age was 51 years, 17 (13.2%) of them had antecedent myelodysplastic syndrome (MDS) and 9 (7.0%) had secondary leukemia. Seventy-eight patients (60.5%) were considered eligible for cure-oriented intensive chemotherapy. Forty-four patients were ineligible of one or more of the following; age over 70, antecedent MDS or secondary leukemia. Additional 7 patients were excluded due to concurrent severe diseases. The median survival of the 129 patients was 441 days with an actuarial 5-year survival of 28.6 +/- 4.4%, and the disease-free survival (DFS) decreased with the increasing age of the patient. In 78 patients who were eligible for intensive chemotherapy, complete remission was achieved in 84.6% and overall DFS was 41.1 +/- 5.9% at 5 years, and their survival was longer than that of ineligible patients. It was suggested that considerable selection of patients, for example, due to old age, already existed before visiting our hospital. Analysis of clinical data of unselected patients might enable the development of a rational approach to the management of elderly patients.

The importance of the real-time fluoroscopic intraoperative direct cholangiogram in the laparoscopic cholecystectomy using a new instrument

BACKGROUND/AIMS

Laparoscopic cholecystectomy (LC) has become an accepted standard operative technique for gallstone treatment worldwide. On the other hand, complications, such as bile duct injuries, have been reported recently with the expansion of indication for LC. Intraoperative cholangiogram (IOC), to minimize the risk of bile duct injury, is now considered to be essential for safe LC. There are disadvantages to IOC such as increased operating time, the possibility of bile duct injury and the difficulties of manipulation.

MATERIAL AND METHODS

We have developed a method for real-time fluoroscopic cholangiograms using a new instrument designed by our group for safe LC. First, a round-tip stylet is inserted through a sheath to coax it gently through the spiral valves of the cystic duct. Secondly, the stylet is removed and the cholangiogram catheter is inserted smoothly. Digital C-arm fluoroscopy provides "real-time" imaging of biliary tree. As a result, we became able to obtain a clear cholangiogram easily in a very short time.

RESULTS

In the first 136 patients, direct cholangiograms were attempted in 106 cases and successfully completed in 102 cases (96.2%).

CONCLUSION

With the development of real-time fluoroscopic intraoperative direct cholangiogram, we are able to cope with bile duct injuries and anomalies, and unsuspected bile duct stones.

Intrinsic signaling function of APP as a novel target of three V642 mutations linked to familial Alzheimer's disease

APP695 is a transmembrane precursor of Abeta amyloid. In familial Alzheimer's disease (FAD), three mutations V642I/F/G were discovered in APP695, which has been suggested by multiple studies to be a cell surface signaling receptor. We previously reported that normal APP695 encodes a potential GO-linked receptor with ligand-regulated function and that expression of the three FAD mutants (FAD-APPs), not normal APP, induces cellular outputs by GO-dependent mechanisms. This suggests that FAD-APPs are constitutively active GO-linked receptors. Here, we provide direct evidence for this notion. Reconstitution of either recombinant FAD-APP with GO vesicles induced activation of GO, which was inhibitable by pertussis toxin, sensitive to Mg2+ and proportional in quantity to the reconstituted amounts of FAD-APP. Consistent with the dominant inheritance of this type of FAD, this function was dominant over normal APP, because little activation was observed in APP695-GO vesicles. Experiments with antibody competition and sequence deletion indicated that His657-Lys676 of FAD-APP, which has been specified as the ligand-dependent GO-coupling domain of normal APP, was responsible for this constitutive activation, confirming that the three FAD-APPs are mutationally activated APP695. This study identifies the intrinsic signaling function of APP to be a novel target of hereditary Alzheimer's disease mutations, providing an in vitro system for the screening of potential FAD inhibitors.

Refractory thrombocytopenia with chromosome 11q23 abnormality

Although cytopenia is a common manifestation of myelodysplastic syndrome (MDS), isolated thrombocytopenia is rare. The term "refractory thrombocytopenia" (RTC) has been proposed as a counterpart of refractory anemia. We describe here a case of RTC associated with chromosome abnormality on 11q23. A 59-year-old man was admitted because of severe thrombocytopenia. A bone marrow examination revealed an increased number of micromegakaryocytes and the absence of normal-sized megakaryocytes without obvious dysplasia in either the myeloid or the erythroid lineage. A remarkable increase of GPIIb/IIIa (CD41a)-positive precursor cells in the bone marrow was observed. Cytogenetic examination detected the chromosome abnormality, an addition on chromosome 11q23. Translocation of the HRX gene was not detectable by Southern blot analysis. The diagnostic problems of isolated thrombocytopenia and possible participation of gene(s) on chromosome 11q23 in megakaryocytopoiesis as well as early hematopoiesis are discussed.

Enhancement and repression of cyanide-insensitive respiration in Aspergillus niger

The biosynthesis of the alternative oxidase protein consisting of cyanide-insensitive and salicylhydroxamic acid-sensitive respiration in Aspergillus niger was investigated. Cyanide-insensitive respiration was enhanced by addition of antimycin A to the incubation mixture, but repressed by the addition of cycloheximide, emetine, puromycin (cytosolic translation inhibitors), carbonylcyanide-m-chlorophenylhydrazone (uncoupler) and actinomycin D (transcription inhibitor). These results show that the alternative oxidase protein of A. niger was synthesized de novo in cytosol and transported in mitochondria.

Immunological studies on venereal spirochetosis of rabbits (rabbit syphilis)

White rabbits in a family, which were clinically diagnosed as moderately or severely diseased with spirochetosis, were bacteriologically and immunologically examined. The specimens from the diseased rabbits, including affected prepuces, scrotum, or skins with an occasional presence of the spirochetes, did not, however, result in growth in six conventional culture media. Serological tests, including quantitative complement fixation test, rapid plasma reagin card test, Treponema pallidum hemagglutination test, and microscopic agglutination test for leptospires using sera from diseased rabbits showed no differences when compared with those of pooled normal rabbit sera. Immunoblot analysis of the polypeptides from three human oral treponemes and three non-oral spirochetes demonstrated that antibodies against several treponemal polypeptides were detected.

Three cases of Pasteurella multocida skin infection from pet cats

We encountered three cases of Pasteurella multocida skin infection from pet cats. P. multocida wound infections are characterized by acute onset of erythema, pain, and swelling. This infection has rarely been reported in dermatology journals from Japan.

Optical profilometry of poly(methylmethacrylate) surfaces after reshaping with a scanning photorefractive keratectomy (SPRK) system

A prototype frequency-quintupled Nd:YAG laser was used with a scanning system to create, on poly(methylmethacrylate) (PMMA) blocks, ablations corresponding to a correction of 6 diopters of myopia by photorefractive keratectomy. The topography of the ablated samples was measured with an optical profilometer to evaluate the smoothness and accuracy of the ablations. The ablation depth was larger than expected. With a 50% to 70% spot overlap, large valleylike variations with a maximum peak-to-peak amplitude of 20 µm were observed. With an 80% spot overlap, the rms surface roughness was 1.3 µm, and the central flattening was 7 diopters. This study shows that optical profilometry can be used to determine precisely the ablation per pulse and the smoothness and accuracy of surface ablations. Knowing the exact ablation per pulse is necessary to produce a smooth and accurate corneal surface by scanning photorefractive keratectomy.

Antiproliferative effect of a novel cholecystokinin-B/gastrin receptor antagonist, YM022

Cholecystokinin (CCK)-B and gastrin receptors are expressed on a variety of human tumor cells. Recently, we have demonstrated that the human brain CCK-B receptors are identical to the gastrin receptors derived from the stomach mucosa, and that the brain-gut peptides, CCK-8 and gastrin I are mitogenic for mouse NIH 3T3 fibroblasts expressing human CCK-B/gastrin receptors (N-hCCKBR). In this report, we evaluated the antiproliferative potency of CCK-B/gastrin receptor antagonists by using N-hCCKBR cells. Among several antagonists, a benzodiazepine derivative, YM022 had the most potent activities in competing with [125I]CCK-8 or [125I]gastrin I binding, inhibition of CCK-8- or gastrin I-induced phosphoinositide hydrolysis and increasing cytoplasmic free calcium. Interestingly, a potent antagonist for rat CCK-B/gastrin receptors did not have such activities in N-hCCKBR cells. YM022 inhibited the CCK-8- or gastrin I-induced [methyl-3H]thymidine incorporation of N-hCCKBR cells in a dose-dependent manner. In the absence of exogenous peptide ligands, YM022 also inhibited the proliferation of several human cancer cell lines expressing the genes for both gastrin and its receptor. These results suggest that YM022 could intervene in the autocrine stimulation of human tumor cell lines through CCK-B/gastrin receptors. N-hCCKBR cells are an excellent tool to screen for novel human CCK-B/gastrin receptor antagonists possessing antiproliferative activity for human cancer cells.

Morphological studies on Mn-SOD, NOS and calcium binding proteins in the rat hippocampus

The immunohistochemical localization of manganese superoxide dismutase (Mn-SOD), nitric oxide synthase (NOS) and calcium (Ca) binding proteins; calbindin-D28K (Calb) and parvalbumin (Parv), was investigated in the rat hippocampus by using a double immunostaining method and an enzyme histochemical staining method. These substances showed considerable regional immunoreactivities in the hippocampus. (1) Although Mn-SOD- and NOS-immunoreactive neurons showed a similar distribution, virtually all of the latter neurons had no or weak Mn-SOD immunoreactivity in all subfields. This finding suggests that NO-producing neurons are not directly associated with Mn-SOD scavenger system in the hippocampus. (2) The co-localization of NOS and Parv or Calb was rarely found throught the hippocampus. (3) Neurons which were intensely immunostained for Mn-SOD were frequently found to be Parv-immunoreactive non-pyramidal cells, or Calb-immunoreactive pyramidal and non-pyramidal cells. From the latter two findings, it is speculated that Ca buffering effects of Parv and Calb are required in Mn-SOD neurons, but not in NO-producing neurons. Since Parv- or Calb-containing non-pyramidal cells are known to be GABAergic, most if not all, Mn-SOD-containing non-pyramidal cells may be GABAergic inhibitory neurons in the rat hippocampus. On the other hand, NOS neurons are also known to belong to GABAergic non-pyramidal cells. Therefore, Mn-SOD and NOS neurons constitute two distinct subclasses of non-pyramidal inhibitory neurons in the hippocampus.

Opitz syndrome in a Japanese male

There have been only a few reports on Opitz syndrome in Japan. We report here a case of a Japanese male with canthal hypertelorism, bilateral cleft lip and palate, scrotal hypospadias with scrotal transposition, and cryptorchidism, findings that met the criteria for this syndrome. After repair of the cleft lip and palate, urethroplasty was performed at age 2, and bilateral orchiopexy was performed at age 3. At age 5, the child is of normal weight for his age, voids urine smoothly on standing, and has slight mental retardation.

Clinical characteristics of three patients with UVs syndrome, a photosensitive disorder with defective DNA repair

Recently, we established a new category of photosensitive disorder termed UVs syndrome. Cells from patients with UVs syndrome have a similar UV sensitivity as xeroderma pigmentosum (XP) cells, but have a normal level of unscheduled DNA synthesis (UDS) unlike XP. UVs syndrome is distinct from Cockayne syndrome (CS) or XP including XP variant (XP-V), as determined by studies of genetic factors using cell fusion, microinjection, and postreplication repair assays. In this study, we identified three Japanese patients with UVs syndrome: an 11-year-old girl, a 17-year-old male, and an 8-year-old boy. The first two patients were siblings, while the third was a case from a different family. All of these patients exhibited acute recurrent sunburn. Common clinical manifestations of these patients were slight erythema and dryness, a number of freckles on sun-exposed areas, and slight telangiectasia only seen on the cheek and nose. Patient 3 showed a lowered minimal erythema dose between 280 and 300 nm. The patients' fibroblasts showed similar characteristics to those in CS, such as UV sensitivity, and a failure of RNA synthesis (RRS) after UV irradiation, despite a normal level of UDS. Thus, UVs syndrome is a new hereditary photosensitive disorder with clinical manifestations similar to a mild form of XP but showing the cellular characteristics of CS.

[Effects of chronic ethanol feeding on lipid composition of rat liver plasma membrane--changes of membrane by acute ethanol loading or its withdrawal in vivo]

The effects of chronic ethanol feeding on lipid composition of rat liver plasma membrane were studied by following ethanol loading or its withdrawal in vivo. Male Wistar rats were pair-fed by a liquid diet containing ethanol as 36% of energy or an isocarolic amounts of glucose for 6 weeks. Chronic ethanol feeding resulted in an increase of cholesterol content and the cholesterol/phospholipid molar ratio in liver plasma membrane compared with pair-fed control rats. Acute ethanol (3 g/kg body weight) orally loading to rats fed ethanol chronically did not change any lipid composition of liver plasma membrane. However, withdrawal of ethanol for 2 days led cholesterol content and the cholesterol/phospholipid molar ratio of liver plasma membrane to be normal values. These data indicated that chronic ethanol feeding produced membrane alterlation that induced resistance to ethanol-induced membrane structural disordering (membrane tolerance), and that this alterlation resulted in a homeoviscous adaptation of liver plasma membrane.

G protein-mediated neuronal DNA fragmentation induced by familial Alzheimer's disease-associated mutants of APP

Missense mutations in the 695-amino acid form of the amyloid precursor protein (APP695) cosegregate with disease phenotype in families with dominantly inherited Alzheimer's disease. These mutations convert valine at position 642 to isoleucine, phenylalanine, or glycine. Expression of these mutant proteins, but not of normal APP695, was shown to induce nucleosomal DNA fragmentation in neuronal cells. Induction of DNA fragmentation required the cytoplasmic domain of the mutants and appeared to be mediated by heterotrimeric guanosine triphosphate-binding proteins (G proteins).

Negative transactivation of cAMP response element by familial Alzheimer's mutants of APP

In familial Alzheimer's disease (FAD), missense point mutations V642I/F/G, which co-segregate with the disease phenotype, have been discovered in amyloid precursor APP695. Here, we report that three FAD mutants (FAD-APPs) negatively regulated the transcriptional activity of cAMP response element (CRE) by a G(o)-dependent mechanism, but expression of wildtype APP695 had no effect on CRE. Experiments with various Galpha(s) chimeras demonstrated that Phe-APP coupled selectively to the C-terminus of Galpha(0). Again, wild-type APP695 had no effect on its C-terminus. These data indicate that FAD-APPs are gain-of-function mutants of APP695 that negatively regulate the CRE activity through G(o). This negative transactivation of CRE is the first biochemically analyzed signal evoked by the three FAD-APPs, but not by wild-type APP695, in a whole-cell system. We discuss the significance of constitutive CRE suppression by FAD-APPs, which is potentially relevant to synaptic malplasticity or memory disorders.