MEK-2, a Caenorhabditis elegans MAP kinase kinase, functions in Ras-mediated vulval induction and other developmental events

Activated Ras initiates a cascade of sequential phosphorylation events, including the protein kinases Raf, MEK, and MAP kinase. The Let-60 Ras-mediated signal transduction pathway controls vulval induction in Caenorhabditis elegans. Both Lin-45 Raf and Sur-1 MAP kinase have been determined to be essential factors during vulval induction; however, the C. elegans mek gene has not been identified. In this paper, we have cloned a C. elegans mek gene, mek-2, and demonstrated that the MEK-2 protein possesses the biochemical properties of MAP kinase kinases: The C. elegans MEK-2 protein can phosphorylate and activate a human MAP kinase (ERK1), and MEK-2 itself can be phosphorylated and activated by immunoprecipitated mammalian Raf. The mek-2 gene plays a key role in the let-60 ras-mediated vulval induction pathway, as loss-of-function mutations in the gene (ku114 and h294) significantly reduce the signal transmitted through Ras. mek-2(ku114) completely suppressed the Multivulva (Muv) phenotype of a hyperactive let-60 ras mutation, and animals homozygous for mek-2(ku114) also displayed a partial larval lethal phenotype. Animals homozygous for mek-2(h294) exhibited a highly penetrant sterile and Vulvaless phenotype. Microinjection of a gain-of-function mek-2 mutation resulted in Muv and other mutant phenotypes, whereas microinjection of a dominant-negative mutation not only suppressed the Muv phenotype of an activated let-60 ras mutation but also caused an egg-laying defective phenotype in otherwise wild type animals. Our results demonstrate that mek-2 acts between lin-45 raf and sur-1/mpk-1 in a signal transduction pathway used in the control of vulval differentiation and other developmental events.

NMR constraints on the location of the retinal chromophore in rhodopsin and bathorhodopsin

Rhodopsin is the photoreceptor in vertebrate rod cells responsible for vision at low light intensities. The photoreactive chromophore in rhodopsin is 11-cis-retinal bound to the protein via a protonated Schiff base with Glu113 as the counterion. We have used the observed 13C NMR chemical shifts of the conjugated retinal carbons in combination with semiempirical molecular orbital calculations to establish the major charge interactions in the retinal binding site of rhodopsin and its primary photoproduct, bathorhodopsin. In rhodopsin, the NMR data constrain one of the carboxylate oxygens (O1) of Glu113 to be approximately 3 A from the C12 position of the retinal with the second oxygen oriented away from the conjugated retinal chain. The O1-C12-H angle is constrained by taking into account the 500 nm absorption maximum of the protein-bound retinal as well as the chemical shift data. The bathorhodopsin retinal binding site structure is generated from the rhodopsin model by isomerization of the C11 = C12 bond and incorporation of C-C single bond twists from C8 to C15. The resulting structure yields a moderate fit to both the chemical shift data and the 543 nm absorption maximum of bathorhodopsin. In both the rhodopsin and bathorhodopsin models, we have included a structural water molecule hydrogen bonded with the Schiff base to account for the high C = N stretching vibrations previously observed.(ABSTRACT TRUNCATED AT 250 WORDS)

[Cyclic changes of serum reproductive hormone levels on patients with endometriosis and infertility]

Fourteen cases of endometriosis (Em) with infertility were studied by laparoscopy in our hospital from Dec. 1988 to Oct. 1989. 2 cases were minimal, 6 cases were moderate and 6 cases were severe. The salpingo examinations of 13 cases were normal by laparoscopy. There were no stigma on ovaries in 7 cases (LUFS). Levels of hormone (E2,P,LH,FSH) were compared in Em with normal women. The level of E2 during the follicle phase in Em was lower (86.4 +/- 6.9 pg/ml) than in normal women (119.9 +/- 7.7 pg/ml, P < 0.01). The LUFS group was compared with the no-LUFS group in Em. During the mid-late follicle phase and ovulatory phase, the E2 values in the LUFS group was significantly lower than in the non-LUFS group (P < 0.05), while the FSH value in LUFS group was significantly higher than in non-LUFS group (P < 0.05).

[Observation on prevention of hepatitis B virus transmission from mother to baby by hepatitis B vaccine]

Forty-two new-born infants whose mothers had been given HBV vaccine before marriage were undergone medical examination for six years. The results showed that the six-month seroconversion rates of anti-HBs among those infants, whose mothers had been immunized successfully, were 90.00% (9/10), and no one was infected by HBV. But the rates of those infants whose mothers were found to be HBsAg(+) and HBsAg/HBeAg(+) before or after marriage were 20.00% (2/10) and 18.18% (4/22), respectively, being much lower than the former. The rates of HBsAg(+) were 70.00% (7/10) and 68.18% (15/22), respectively. This led to the conclusion that immunization with HBV vaccine before marriage will partly break the HBV transmission chain of "couples-mother and her baby-population".

Effects of interleukin-6 on hematopoiesis in allogeneic and syngeneic bone marrow chimeras

Effects of interleukin-6 (IL-6) on hematopoietic progenitor cells were analyzed in murine bone marrow chimeras. When IL-6 was injected into syngeneic [C3H/He-->C3H/He] bone marrow chimeras from day 1 to day 12, the numbers of highly proliferative potential colony-forming units (CFU-HPP) or colony-forming units mix (CFU-Mix) in spleen cells and bone marrow cells increased on day 14 although there was a marked increase in spleen cells but not in bone marrow cells on day 21. The numbers of CFU-HPP increased in spleen cells from allogeneic [BALB/c-->C3H/He] bone marrow chimeras injected with IL-6 on days 14 and 21. In syngeneic bone marrow chimeras, the numbers of colony-forming units granulocyte/macrophage (CFU-GM) and burst colony-forming units (BFU-E) increased similarly to those of CFU-HPP and CFU-Mix on day 14. On day 21, these were mainly increased in spleen cells. In allogeneic bone marrow chimeras, IL-6 decreased the numbers of CFU-GM and BFU-Mix dose-dependently on day 14. Only 10 micrograms of IL-6 increased the numbers of CFU-GM and BFU-E on day 21. In our previous work, we showed that platelet counts increased on day 14 in syngeneic bone marrow chimeras injected with IL-6, whereas platelet and leukocyte counts increased on days 14 and 24 in allogeneic bone marrow chimeras injected with IL-6, correlating inversely with the numbers of hematopoietic progenitor cells. Overall, primitive hematopoietic progenitors (i.e., CFU-HPP and CFU-Mix) existed primarily in spleen cells of allogeneic bone marrow chimeras on day 14, whereas those in spleen cells of syngeneic bone marrow chimeras were found on day 21. These findings indicate that the effect of IL-6 on hematopoiesis in allogeneic bone marrow chimeras is completely different from that in syngeneic bone marrow chimeras, probably via graft-versus-host reaction (GVHR) but not GVH disease (GVHD).

Recipient-mediated effect of a traditional Chinese herbal medicine, ren-shen-yang-rong-tang (Japanese name: ninjin-youei-to), on hematopoietic recovery following lethal irradiation and syngeneic bone marrow transplantation

Ren-shen-yang-rong-tang (Japanese name: Ninjin-youei-to, NYT), a traditional Chinese herbal medicine, was evaluated for recipient-mediated effect on hematopoietic recovery in a murine model of syngeneic bone marrow transplantation (BMT). BALB/c recipient mice were preconditioned with a lethal total body irradiation (TBI) at a dose of 6.5 Gy and transplanted with syngeneic bone marrow (BM) cells. NYT treatments, given intraperitoneally (i.p.) once per day for 3 consecutive days in a dose of 0.625 mg, were performed either before or after TBI and BMT to assess any recipient-mediated effect of this compound. NYT pretreatment was as effective as NYT posttreatment in enhancing the total number of colony-forming unit erythroid (CFU-E) and colony-forming unit granulocyte-macrophage (CFU-GM) per marrow and spleen after TBI and BMT. NYT pretreatment caused a significant increase in marrow and splenic CFU-E and CFU-GM numbers over a prolonged period following TBI and BMT, and affected late-stage erythropoiesis (CFU-E) more profoundly than early-stage erythropoiesis (burst-forming unit erythroid, BFU-E). NYT pretreatment significantly accelerate recovery of not only erythrocyte and leukocyte counts but also platelet counts after transplantation with a limited number (1 x 10(5)) of BM cells. The same treatment, however, was significantly less effective in hematopoietic recovery after transplantation with a minimal number (1 x 10(4)) of BM cells, indicating that NYT accelerates recovery of donor-derived rather than recipient-derived cells.(ABSTRACT TRUNCATED AT 250 WORDS)

In vivo effects of the immunosuppressant 15-deoxyspergualin on hematopoiesis in murine allogeneic bone marrow chimeras. Its thrombopoietic activity and reversal of adverse effects with granulocyte colony-stimulating factor and/or erythropoietin

When 15-deoxyspergualin (DSG), a potent immunosuppressant, was administered into [BALB/c-->C3H/He] bone marrow chimeras from day 14 to day 25, increased thrombopoiesis was induced on day 20 to day 33, accompanied by marked leukocytopenia and anemia. The mean platelet counts in DSG-treated and control [BALB/c-->C3H/He] bone marrow chimeras on day 25 were (114.1 +/- 0.5) x 10(4)/microliter versus (58.6 +/- 2.6) x 10(4)/microliter (1.9-fold increase). Colony-forming units-megakaryocyte (CFU-Meg) were not significantly increased in DSG-treated bone marrow chimeras. Colony-forming units-granulocyte/macrophage (CFU-GM) and burst-forming units-erythroid (BFU-E) were decreased during DSG-treatment whereas CFU-Mix colony formations were rather increased, and more primitive hematopoietic progenitor cells (highly proliferative potential colony-forming units [CFU-HPP]) were not decreased in the same time period. Since CFU-GM and BFU-E colony formations were increased immediately after the cessation of DSG treatment, followed by the rebound of leukocyte counts and the recovery of hemoglobin (Hb) levels, the leukocytopenia and anemia appeared to be induced by a cytostatic effect of DSG. The adverse effect of DSG was partly reversed by the simultaneous administration of granulocyte colony-stimulating factor (G-CSF) and/or erythropoietin (EPO), suggesting the need for the administration of these cytokines in the case of bone marrow transplants treated with DSG. Furthermore, it was of note that DSG modulated hematopoiesis and stimulated the production of thrombopoietin (TPO)-like cytokine(s) as well as interleukin-3 (IL-3).

A case-control epidemiologic study of endometriosis

A case-control study involving 203 cases of pelvic endometriosis seen from 1987-1989, and 406 randomly selected and age-matched community controls was conducted in order to provide information relevant to effective prophylaxis of the disease. The diagnosis was confirmed by pathology from laparotomy and/or laparoscopy. A questionnaire focused on menstrual, marital and reproductive status, professional exposure and physical activities, and the results were analyzed by a conditional logistic regression model. Women characterized by earlier menarche (< or = 12 years) and longer period (> or = 8 days) were found to be associated with an elevated incurring risk, and a trend of increasing risk associated with primary dysmenorrhea (RR = 2.1 for mild to moderate and RR = 5.2 for severe dysmenorrhea), energetic physical activity during menstruation (RR = 2.1), and allergic diathesis (RR = 1.8) was seen. An inverse relationship was observed between the number of pregnancies and risk of endometriosis, and the protective effect was most significant when only the number of full-term pregnancies was counted. The risk factors of endometriosis are discussed, and intensive treatment of primary dysmenorrhea and avoidance of strenuous exercise during menstruation are identified as important measures in the prevention of endometriosis.

In vivo administration of interleukin-6 in murine allogeneic bone marrow chimeras: early and delayed enhancement of hematopoiesis accompanied with split tolerance but not with graft-versus-host disease

Interleukin-6 (IL-6) induced increased, leukocyte and platelet counts on around day 20 when it was administered into [BALB/c-->C3H/He] bone marrow chimeras from day 1 to day 12. Increased leukocyte counts and hemoglobin (Hb) levels were also observed at around day 60 and from day 41 to 80, respectively. On the other hand, hematopoietic recovery in [C3H/He-->C3H/He] bone marrow chimeras injected with IL-6 was different from that in [BALB/c-->C3H/He] bone marrow chimeras, showing no delayed and long-lasting increase in Hb levels but showing an early and transient increase in Hb levels and platelet counts. Sera from [BALB/c-->C3H/He] bone marrow chimeras injected with IL-6 showed predominant productions of IL-3 and/or IL-4. Reverse transcriptase polymerase chain reaction (RT-PCR) showed that stem cell factor (SCF) mRNA expression was increased in bone marrow or spleen cells from [BALB/c-->C3H/He] bone marrow chimeras injected with IL-6 on day 36. Furthermore, we analyzed influence of IL-6 on graft-versus-host disease (GVHD) in [BALB/c-->C3H/He] bone marrow chimeras injected with IL-6. Decreased survival days and body weights were not observed when compared with the control. Histopathological changes of the liver due to GVHD were also not obvious. However, alloreactive mixed lymphocyte reactions (MLRs) were readily detected although cytotoxic T cells were not generated. Since H-2 typing showed that donor-type chimerism was predominantly observed, it was suggested that split tolerance might be induced by IL-6 administration. Increased IL-2 levels were not detected in sera from [BALB/c-->C3H/He] bone marrow chimeras injected with IL-6 whereas IL-4 was detected in the same sera, indicating that type 2 helper T (TH2) cells appeared to be predominantly generated. These results suggest that IL-3/IL-4 and SCF appeared to synergistically support delayed effects on hematopoiesis in [BALB/c-->C3H/He] bone marrow chimeras injected with IL-6 although early effects appeared to be mediated mainly by IL-6 directly or indirectly. Furthermore, IL-6 could induce split tolerance in [BALB/c-->C3H/He] bone marrow chimeras via a preferable activation of TH2 type cells without inducing severe GVHD.

Pharmacokinetics of cadmium in ewes: a preliminary study

A pharmacokinetic analysis of cadmium was carried out by administering cadmium chloride i.v. to 3 ewes. Each received 0.033, 0.1 and 0.33 mg cadmium/kg body weight, with each administration separated by 21 d. Pharmacokinetic parameters were determined using a 3-compartment open model (multiple dosage analysis). The half life of elimination reached 40 to 50 d, the body clearance was 0.3 to 0.4 L/kg/d, and the steady-state volume of distribution was 6 to 28 L/kg. The invariability of the values of the elimination parameters and the good fitting of the mathematical model to the experimental values are in agreement with linear kinetics for cadmium in the ewe.

Suppression of activated Let-60 ras protein defines a role of Caenorhabditis elegans Sur-1 MAP kinase in vulval differentiation

The let-60 ras gene of Caenorhabditis elegans is one of the key players in a signal transduction pathway that controls the choice between vulval and epidermal differentiation in response to extracellular signals. To identify components acting downstream of let-60 ras in the vulval signaling pathway, we have identified a reduction-of-function mutation in the sur-1 gene that completely suppresses the multivulva phenotype of a hyperactive let-60 ras mutation. About 10% of animals homozygous for the sur-1 mutation also display a specific and intriguing vulval cell lineage defect. In addition, the sur-1 mutation results in a cold-sensitive egg-laying defective phenotype and a partial larval lethal phenotype. We have cloned the sur-1 gene by DNA-mediated transformation and have shown that it encodes a protein similar in overall structure to mammalian MAP kinases (ERKs). The functional homology between Sur-1 MAP kinase and mammalian MAP kinases was also demonstrated by the ability of a rat ERK2 kinase to rescue the sur-1 mutant phenotypes. Genetic double-mutant analyses place sur-1 downstream of let-60 ras but upstream of lin-1 in the vulval signaling pathway. Our results provide further evidence for the extreme conservation of Ras-mediated signaling pathway between worms and humans and for the function of MAP kinases in cell signaling processes that control cell differentiation and animal development.

Endoscopic variceal ligation. Experience in 78 patients

Endoscopic variceal ligation (EVL) is a new alternative to sclerotherapy in the treatment of esophageal variceal hemorrhage, which results in strangulation, necrosis and scar formation of varices without systemic or local adverse effect. From May 1, 1991 through July 1, 1992, EVL was performed in 78 consecutive patients, in 35 of them it was performed during active massive bleeding, and active bleeding was controlled by the initial session in 31 patients. With repeated EVL treatment, 32 patients had their varices obliterated. The varices had reduced in size in other patients. No ligation-related complications were observed. This procedure is a safe, effective and rather simple method to treat esophageal varices, especially in patients with poor liver function and recurrent bleeding after devascularization or shunt surgery.

Localization of the retinal protonated Schiff base counterion in rhodopsin

Semiempirical molecular orbital calculations are combined with 13C NMR chemical shifts to localize the counterion in the retinal binding site of vertebrate rhodopsin. Charge densities along the polyene chain are calculated for an 11-cis-retinylidene protonated Schiff base (11-cis-RPSB) chromophore with 1) a chloride counterion at various distances from the Schiff base nitrogen, 2) one or two chloride counterions at different positions along the retinal chain from C10 to C15 and at the Schiff base nitrogen, and 3) a carboxylate counterion out of the retinal plane near C12. Increasing the distance of the negative counterion from the Schiff base results in an enhancement of alternating negative and positive partial charge on the even- and odd-numbered carbons, respectively, when compared to the 11-cis-RPSB chloride model compound. In contrast, the observed 13C NMR data of rhodopsin exhibit downfield chemical shifts from C8 to C13 relative to the 11-cis-RPSB.Cl corresponding to a net increase of partial positive or decrease of partial negative charge at these positions (Smith, S. O., I. Palings, M. E. Miley, J. Courtin, H. de Groot, J. Lugtenburg, R. A. Mathies, and R. G. Griffin. 1990. Biochemistry. 29:8158-8164). The anomalous changes in charge density reflected in the rhodopsin NMR chemical shifts can be qualitatively modeled by placing a single negative charge above C12. The calculated fit improves when a carboxylate counterion is used to model the retinal binding site. Inclusion of water in the model does not alter the fit to the NMR data, although it is consistent with observations based on other methods. These data constrain the location and the orientation of the Glu113 side chain, which is known to be the counterion in rhodopsin, and argue for a strong interaction centered at C12 of the retinylidene chain.

Role of a raf proto-oncogene during Caenorhabditis elegans vulval development

During Caenorhabditis elegans vulval induction, multipotent precursors respond to an inductive signal by generating vulval cells as opposed to non-specialized epidermal cells. Both classical and 'reverse' genetic approaches have revealed that a cascade of nematode homologues of mammalian proto-oncogenes is necessary for induction of the vulva. The inductive signal is a growth factor encoded by the lin-3 gene and its candidate receptor is a tyrosine kinase encoded by the let-23 gene. let-23 acts via a Ras protein encoded by the let-60 gene. A nematode homologue of mammalian raf family protein serine/threonine kinases has been cloned and found to be encoded by the lin-45 gene. Dominant negative lin-45 raf mutants prevent vulval induction. A recessive lin-45 raf mutation prevents the excessive vulval differentiation caused by activated ras, indicating that raf might act downstream of ras during vulval induction.

C. elegans lin-45 raf gene participates in let-60 ras-stimulated vulval differentiation

Vulval differentiation in Caenorhabditis elegans is controlled by intercellular signalling mediated by a receptor tyrosine kinase and a ras gene product. The lin-45 gene encodes a homologue of the raf family of serine/threonine kinases and is necessary for vulval differentiation. The lin-45 raf gene product appears to act downstream of the ras protein in this pathway. A proto-oncogene-mediated signalling pathway may be a common feature of metazoan development.

In vitro expansion of murine hematopoietic progenitor cells in liquid cultures for bone marrow transplantation: effects of stem cell factor

In this study, we demonstrated that recombinant stem cell factor (SCF), when used in combination with interleukin-1 (IL-1), IL-3 and IL-1 plus IL-3, promoted the expansion of immature murine hematopoietic progenitor cells in liquid cultures. In cultures with IL-1 plus IL-3 plus SCF, high proliferative potential-colony forming cells (HPP-CFC) increased 7-8-fold compared with the increase in fresh bone marrow cells, while SCF alone had no effect on the expansion of HPP-CFC. SCF also increased the numbers of colony forming unit-spleen (CFU-S) cells in combination with IL-1 plus IL-3. Transplantation of bone marrow cells cultured with IL-1 plus IL-3 plus SCF resulted in reconstitution of hematopoiesis in lethally irradiated mice earlier than transplantation of fresh bone marrow cells. These results raised the possibility that in vitro expansion of hematopoietic progenitor cells, carried out with SCF in combination with IL-1 and IL-3 in liquid cultures, can be utilized in bone marrow transplantation.

[Primary Waldenström's macroglobulinemia associated with pure red cell aplasia in which Ts/c lymphocytes inhibiting erythroid precursors were detected]

Waldenström's macroglobulinemia (WMG) is a malignancy of B lymphocytes manifesting heavy accumulation of monoclonal IgM in the plasma. In about 80% cases of WMG, Normocytic normochronic anemia (NNA) is complicated. A case of WMG complicated with pure red cell aplasia (PRCA) and the results of in vitro CFU-E colony assay of bone marrow mononuclear cells (BMMNC) cultured with the patient's serum and/or peripheral lymphocytes were described. A 59-year-old male was admitted with serum total protein Level of 9.7g/dl and 48.2% of gamma globulin. The diagnosis of WMG was made by monoclonal IgM in immunoelectrophoresis. Severe NNA was initially demonstrated on admission and gradually deteriorated further. Both reticulocytes in peripheral blood and erythroid precursors in bone marrow were markedly decreased. Erythropoietin showed high values in plasma. Complication by PRCA was considered to be present in vitro study of a CFU-E colony formation of BMMNC from a normal volunteer showed significant suppression on addition of the patient's peripheral lymphocytes and adverse enhancement by adding the patient's serum. This inhibition of CFU-E colony formation was most prominent by the addition of suppressor/cytotoxic T lymphocytes (Ts/c) and was dose dependent. This result showed the existence of inhibitory Ts/c against proliferation of allogeneic erythroid precursors.

The value of hysteroscopy in the diagnosis of infertility and habitual abortion

Ninety cases of infertility and habitual abortion were analyzed by hysteroscopy between April 1983 and July 1990 in PUMC hospital. Abnormal changes of the uterine cavity were seen in 74.4%. The result of hysterosalpingography corresponded with that of hysteroscopy in 62.5%, and the result of B-ultrasound corresponded to that of hysteroscopy in 52.5%. The diagnosis of adhesion and polyps of the uterine cavity was made accurately by hysteroscopy, and both could be operated under hysteroscopy. After operative removal of the adhesion, an IUD should be put into the uterine cavity for 3 months. In 60 cases operations were performed during or after hysteroscopy. Of the 45 patients followed, 19 achieved pregnancy. Five patients achieved pregnancy after operative removal of the adhesion. It is concluded that hysteroscopy is more important than B-ultrasound and hysterosalpingography in the examination and treatment of infertility.

Synergistic effects of murine stem cell factor in combination with a variety of cytokines on the expansion of murine hematopoietic progenitor cells in short-term suspension cultures

In the present study, it is represented that the ability of murine stem cell factor (SCF) to expand hematopoietic progenitor cells in short-term suspension culture when used alone or with IL-1 beta, IL-3, IL-6, M-CSF and IL1 beta Plus IL-3. SCF alone had a limited effect on the expansion of early primitive hematopoietic progenitor cells (CFU-HPP: high proliferative potential colony forming unit, and CFU-S: colony forming unit in spleen) even at a high concentration, but expanded mature hematopoietic progenitor cells (CFU-GM: colony forming unit-granulocyte/macrophage, and BFU-E: burst forming unit-erythroid) markedly at low concentrations. When SCF was used in combination with other cytokines, the expansion of primitive hematopoietic progenitor cells was significantly increased; namely, CFU-HPP were expanded approximately 2 to 5-fold compared with SCF alone. A marked expansion of hematopoietic progenitor cells was observed in a combination of SCF plus IL-1 beta plus IL-3. In this setting, CFU-S was increased 2.2-fold compared with the number of CFU-S in fresh bone marrow and CFU-HPP were increased 8.5-fold compared with the number of primary CFU-HPP. These results suggest that these factors may be utilized in experiments of murine bone marrow transplantation (BMT) and also in human BMT. Namely, the adequate number of hematopoiesic progenitor cells and stem cells required for the successful engraftment can be obtained from small volume of peripheral or bone marrow blood by this procedure, thus obtiating the donor's burden.

Ras proteins in developmental pattern formation in Caenorhabditis elegans and Drosophila

Recent studies of genetically isolated mutants in Caenorhabditis elegans and Drosophila have revealed ras functions in developmental pattern formation. The ras proteins act as genetic switches to determine cell fates between two alternative choices during C elegans vulval development (vulval versus hypodermal cells) and during Drosophila eye development (R7 versus cone cell). In both cases, ras proteins act downstream of a receptor tyrosine kinase in a signal transduction pathway that mediates cell-cell interactions. These genetic systems may allow the further elucidation of ras-mediated developmental regulatory pathways.

[Hepatectomy under continuous normothermic interruption of hepatic blood flow in noncirrhotic patients]

Continuous normothermic interruption of hepatic blood flow for 20 minutes or longer was applied in 37 non-cirrhotic patients, including 7 having emergency operation and 30 elective operation. Hepatic blood inflow was interrupted for 40 to 47 minutes in 4 patients, 30 to 39 minutes in 7, 25 to 29 minutes in 14, and 20 to 24 minutes in 12. Postoperatively, 1 patient died of recurrent hemobilia, which was not related to intraoperative vascular interruption. Two patients had mild jaundice for 1 week after right trilobectomy, while the remaining 34 patients recovered uneventfully with no clinical hepatic insufficiency. This method is considered simple, safe, and acceptable for hepatic resection in non-cirrhotic patients.

Analysis of dominant-negative mutations of the Caenorhabditis elegans let-60 ras gene

The let-60 gene of Caenorhabditis elegans controls the choice between vulval and hypodermal differentiation in response to an inductive signal from the gonad. let-60 encodes a ras protein that acts downstream of the let-23 receptor tyrosine kinase in a signal transduction pathway. Dominant-negative mutations of let-60 [let-60(dn)] cause a reduction of the gene activity in let-60(dn)/+ heterozygotes and a vulva-less mutant phenotype. We have found that nine let-60(dn) mutations cause replacements of conserved residues. Four are in two novel positions; others are in positions known previously to cause dominant-negative mutations in mammalian cells. The locations of these lesions suggest that they disrupt the ability of the ras protein to bind guanine nucleotides. Four let-60(dn) mutant genes were introduced into wild-type animals in the form of extrachromosomal arrays and were found to generate three dominant phenotypes--lethality, vulva-less, or multivulva--depending on gene dose and alleles. The dominant lethality caused by high-dose transgenic let-60(dn) genes suggests a toxic effect of these mutant genes in early development. The dominant-negative effects of these mutations in heterozygotes are likely to be caused by competition between let-60(dn) and let-60(+) protein for a positive regulator. All let-60(dn) mutations interfere with let-60(+) activity, but some alleles have partial constitutive activity, suggesting that the ability to interact with the activator is separable from the ability to exert a physiological effect (stimulation of vulval differentiation). These dn mutations might be useful for interfering with ras-mediated signal transduction pathways in other multicellular organisms.

Short intussusception valves prevent reflux after jejunal interposition bilioduodenal anastomosis

Short whole circumference and semi-circumference intussusception valves were created in interposition cholecysto-jejunal-duodenal conduits in pigs to determine which method best prevented gastrointestinal reflux into the biliary tract. Following intravenous injection of 99 mTc-HIDA the time interval for its excretion from the liver and appearance in the duodenum was not different in either whole or semi-circumference valve animals or in controls without valves. After intragastric administration of 99 mTc-DTPA the relative radioactivity of gallbladder contents (reflux) in the cohort without valves was significantly higher than in both cohorts with valves. Animals with semi-circumferential valves in turn had significantly higher levels of nuclide than those with whole circumference valves. Reflux was observed grossly in 100% of animals without valves, in 20% of those with semi-circumference valves, and in no animals with whole circumference valves. This study indicates that both whole and semi-circumference intussusception valves placed in jejunal biliary conduits allow unimpeded flow of bile into the gastrointestinal tract. Whole circumference valves are more effective for prevention of reflux than semi-circumferential valves.

The influence of electrocortical biofeedback on performance in pre-elite archers

The purpose of the present research was to determine whether EEG biofeedback training could improve archery performance as well as self-reported measures of concentration and self-confidence. Experienced pre-elite male (N = 16) and female (N = 8) archers were randomly assigned to one of three treatment conditions: (a) correct feedback (i.e., greater left hemisphere low frequency activity), (b) incorrect feedback (i.e., greater right hemisphere low frequency activity), and (c) no feedback control. The pretest and posttest consisted of 27 shots, with EEG data collected for the left and right temporal hemispheres (T3, T4). Feedback subjects were then given EEG biofeedback, while control subjects rested for 30 min. Analyses indicated that only the performance measure was significant. The correct feedback group significantly improved performance, while the incorrect feedback group showed a significant performance decrement from pre- to posttest (Ps less than 0.05). The control group showed no significant pre-post differences in performance. EEG analyses showed differences that were consistent with the training given to the incorrect, but not the correct, feedback group. Overall, the results provide some support for the use of known relationships between EEG and performance as an effective means of providing biofeedback to affect the performance of pre-elite archers.

The let-60 locus controls the switch between vulval and nonvulval cell fates in Caenorhabditis elegans

During induction of the Caenorhabditis elegans hermaphrodite vulva by the anchor cell of the gonad, six multipotent vulval precursor cells (VPCs) have two distinct fates: three VPCs generate the vulva and the other three VPCs generate nonspecialized hypodermis. Genes that control the fates of the VPCs in response to the anchor cell signal are defined by mutations that cause all six VPCs to generate vulval tissue (Multivulva or Muv) or that cause all six VPCs to generate hypodermis (Vulvaless or Vul). Seven dominant Vul mutations were isolated as dominant suppressors of a lin-15 Muv mutation. These mutations are dominant alleles of the gene let-60, previously identified only by recessive lethal mutations. Our genetic studies of these dominant Vul recessive lethal mutations, recessive lethal mutations, intragenic revertants of the dominant Vul mutations, and the closely mapping semi-dominant multivulva lin-34 mutations suggest that: (1) loss-of-function mutations of let-60 are recessive lethal at a larval stage, but they also cause a Vul phenotype if the lethality is rescued maternally by a lin-34 gain-of-function mutation. (2) The dominant Vul alleles of let-60 are dominant negative mutations whose gene products compete with wild-type activity. (3) lin-34 semidominant Muv alleles are either gain-of-function mutations of let-60 or gain-of-function mutations of an intimately related gene that elevates let-60 activity. We propose that let-60 activity controls VPC fates. In a wild-type animal, reception by a VPC of inductive signal activates let-60, and it generates into a vulval cell type; in absence of inductive signal, let-60 activity is low and the VPC generates hypodermal cells. Our genetic interaction studies suggest that let-60 acts downstream of let-23 and lin-15 and upstream of lin-1 and lin-12 in the genetic pathway specifying the switch between vulval and nonvulval cell types.

let-60, a gene that specifies cell fates during C. elegans vulval induction, encodes a ras protein

Genetic analysis previously suggested that the let-60 gene controls the switch between vulval and hypodermal cell fates during C. elegans vulval induction. We have cloned the let-60 gene, and shown that it encodes a gene product identical in 84% of its first 164 amino acids to ras gene products from other vertebrate and invertebrate species. This conservation suggests that the let-60 product contains all the biochemical functions of ras proteins. Extrachromosomal arrays of let-60 ras DNA cause cell-type misspecification (extra vulval fates) phenotypically opposite to that caused by let-60 ras loss-of-function mutations (no vulval fates), and suppress the vulvaless phenotype of mutations in two other genes necessary for vulval induction. Thus, the level and pattern of let-60 ras expression may be under strict regulation; increase in let-60 ras activity bypasses or reduces the need for upstream genes in the vulval induction pathway.

Nucleosome loss activates yeast downstream promoters in vivo

Nucleosome depletion can be made to occur in yeast by addition of glucose to strains containing the histone H4 gene under GAL promoter control. This leads to the activation of downstream promoter elements (TATA box and initiation, I, region) of three different regulated yeast promoters fused to the E. coli lacZ gene. Nucleosome loss activates the PHO5 downstream element in the presence or absence of the upstream activator sequences (UAS) through which PHO5 induction is normally mediated. The cytochrome C (CYC1) and galactokinase (GAL1) promoters are normally repressed by glucose through their UAS elements. However, when these UAS are deleted, the remaining downstream promoters are also activated by glucose-mediated nucleosome loss. These data suggest that nucleosome loss increases transcription initiation and subsequent elongation in vivo. They also indicate that the proteins which recognize the downstream promoter are activated and functional, at least in part, even in the absence of the UAS complex.

Extremely conserved histone H4 N terminus is dispensable for growth but essential for repressing the silent mating loci in yeast

Yeast histone H4 function was probed in vivo by deleting segments of this extremely conserved 102 amino acid protein. Deletions in the hydrophobic core of H4 are lethal and block chromosomal segregation. In contrast, deletions at the hydrophilic N terminus (residues 4-28) and C terminus (residues 100-102) are viable. However, N-terminal deletion alters normal chromatin structure and lengthens the cell cycle, especially G2. Surprisingly, removal of the H4 N terminus also derepresses the silent mating type loci, HML alpha and HMRa, disrupting mating. This activation is specific since other regulated genes (GAL10, PHO5, CUP1) are repressed and induced normally in these cells. Deletions of the hydrophilic N termini of H2A or H2B do not show this effect on mating. These experiments allow us to define a unique H4 function that is not shared by other histones (H2A and H2B).

D-lysergic acid activation and cell-free synthesis of D-lysergyl peptides in enzyme fractions from the ergot fungus Claviceps purpurea

The D-lysergic acid activating enzyme from the ergot fungus Claviceps purpurea was purified to near homogeneity. It has a native Mr of about 245,000 and in its denatured form is a single polypeptide chain of Mr 62,000. The enzyme catalyzes the ATP-pyrophosphate exchange reaction dependent on D-lysergic acid and, though much less, that dependent on dihydrolysergic acid. Western blot analysis of SDS electropherograms of crude protein extracts from C. purpurea using monospecific antibodies directed against the D-lysergic acid activating enzyme revealed the immunostaining of one particular band which was identical with that of the D-lysergic acid activating enzyme. No significant immunoreactive band with higher molecular weight was seen, which precludes the possibility that the enzyme had arisen from the proteolysis of a high molecular weight ergot peptide synthetase. An ammonium sulfate fractionated enzyme fraction was prepared from C. purpurea strain C1 that catalyzed the incorporation of D-lysergic acid into two peptides which besides D-lysergic acid contained alanine, phenylalanine, and proline. Dihydrolysergic acid was efficiently incorporated into the corresponding dihydrolysergic acid containing analogues of the two compounds. Radiochemical analysis and degradation studies suggest that the two D-lysergic acid containing peptides most probably are N-[N-(D-lysergyl)-L-alanlyl]-L-phenylalanyl-L-proline lactam and N-[N-(D-lysergyl)-L-analyl]-L-phenylalanyl-D-proline lactam, respectively. N-[N-(D-Lysergyl)-L-alanyl]-L-phenylalanyl-L-proline lactam is considered to be the immediate precursor of ergotamine.(ABSTRACT TRUNCATED AT 250 WORDS)

Depletion of histone H4 and nucleosomes activates the PHO5 gene in Saccharomyces cerevisiae

We have previously constructed a yeast strain (UKY403) whose sole histone H4 gene is under control of the GAL1 promoter. This yeast arrests in G2 upon glucose treatment as a result of histone H4 depletion. The yeast PHO5 gene contains phase nucleosomes covering promoter (UAS) sequences in the PHO5 repressed state and it has been suggested that nucleosomes prevent the binding of positively acting factors to these UAS sequences. Using UKY403 we examined the length of polynucleosomes and nucleosome phasing in the PHO5 upstream region by the use of micrococcal nuclease and indirect end-labeling. It was found that glucose arrest led to a severe disruption in PHO5 chromatin structure and that most nucleosomes had their position altered or were lost from the PHO5 promoter region. Cell undergoing nucleosome depletion synthesized large quantities of accurate PHO5 transcripts even under repressive, high inorganic phosphate conditions. Histone H4 depletion did not appear to affect the repression or activation of another inducible yeast gene, CUP1. Arrest with landmarks in early G1 (in the cell division cycle mutant cdc28) or in various stages of G2 (in cdc15, cdc17 and cdc20) does not activate PHO5; nor does arrest due to chromosome topology changes (in top2 or the top1top2 topoisomerase mutants). cdc14, which has its arrest landmark at a similar point in the cell cycle as cdc15, does derepress PHO5. However, since it also leads to derepression of CUP1 it is probably functioning through an independent mechanism. Therefore, our data suggest that nucleosomes regulate PHO5 transcription.

Effects of histone H4 depletion on the cell cycle and transcription of Saccharomyces cerevisiae

We have constructed a yeast strain (UKY403) in which the sole histone H4 gene is under control of the GAL1 promoter. This allows the activation of H4 mRNA synthesis on galactose and its repression on glucose. UKY403 cells, pre-synchronized in G1 with alpha-mating factor, have been used to show that glucose treatment results in the loss of approximately half the chromosomal nucleosomes. This depletion is only partially reversible when the H4 gene is reactivated on galactose. It was found that the resultant lethality manifests itself first in S phase, the period of nucleosome assembly, but leads to highly synchronous arrest in G2 and a virtually complete block in chromosomal segregation. Histone H4-depleted chromatin was analyzed for its efficiency as a template for all three RNA polymerases. Using pulse-labeling, we find no evidence for altered transcription by RNA polymerase I (25S, 18S and 5.8S rRNAs) or RNA polymerase III (5S rRNA, tRNAs). Northern blot analysis was used to measure levels of RNA polymerase II transcripts. There was little effect on the activation or repression of the CUP1 chelatin gene. While there may be some decrease in the level of certain mRNAs (e.g. HIS4, ARG4) other message levels (HIS3, TRP1) show little change upon glucose repression. Therefore, nucleosome loss certainly does not have a general effect on transcription.

Histone H2B repression causes cell-cycle-specific arrest in yeast: effects on chromosomal segregation, replication, and transcription

To determine which cellular processes are dependent on histones, we blocked histone H2B mRNA synthesis in asynchronously growing yeast after fusing the H2B gene to a repressible GAL10 promoter. Chromosomal segregation, replication, and transcription were then examined. We found that the cells arrested in mitosis, with a cell division cycle (cdc) phenotype. Chromatin structure and nuclear segregation were disrupted. A full round of DNA replication took place after the repression of histone H2B mRNA synthesis. Active transcription and the induction of new transcripts also continued in the arrested cells.

Yeast histone H2A and H2B amino termini have interchangeable functions

The N-terminal ends of histones H2B and H2A have very different sequences and rates of evolution. However, they both extend from the nucleosome core and are positively charged. Short sequences at the C termini of both proteins also differ from each other and appear to be hydrophilic. Deletions at the N and C termini of yeast histones H2B2 and H2A1 do not obviously affect the cell's viability under normal growth conditions. However, deletions at the N termini of both H2B and H2A in the same cell are lethal or result in greatly reduced viability. Even switching portions of the N termini between H2B and H2A to create two chimeric histone proteins within the same cell has no obvious effect on viability. This supports the argument that the N-terminal end of one protein complements the function of the other.

Adenovirus stimulation of transcription by RNA polymerase III: evidence for an E1A-dependent increase in transcription factor IIIC concentration

Human cells expressing adenovirus E1A proteins transcribe transfected tRNA and adenovirus VAI genes at greater than 10-fold higher levels than uninfected HeLa cells. Here we show that the increased transcription observed in vivo is reflected in the in vitro transcriptional activity of cell extracts. Depletion of E1A protein from these extracts by immunoprecipitation with a monoclonal antibody did not diminish the activity, suggesting that E1A proteins do not stimulate transcription directly. Fractionation of the extracts by chromatography on phosphocellulose suggests that the higher activity of extracts of adenovirus-infected cells was due to increased activity of the transcription factor (TF) which is the limiting component required for specific initiation of tRNA and VAI transcription in extracts of uninfected HeLa cells, i.e. TFIIIC. Template commitment titrations further suggest that the increased TFIIIC activity was due to an increase in the concentration of active TFIIIC. On the basis of these results and recent genetic analyses of early adenovirus promoters, we suggest that E1A proteins stimulate transcription of adenovirus genes indirectly by increasing the effective in vivo concentration of the limiting cellular transcription factors required for their transcription.

Crossed aphasia in a right-handed bilingual Chinese man: a second case

A persistent nonfluent aphasia following a right cerebral infarction developed in a 74-year-old right-handed Chinese man. Computerized axial tomography localized the lesion in the right frontal lobe. This case is similar to a previously reported one, also with crossed aphasia in a bilingual and dextral Chinese person. Despite these two independent observations and in spite of the fact that unusual cerebral organization might be related to early learning of a nonalphabetic (ideographic) language, preliminary sampling has failed to demonstrate a greater incidence of crossed aphasia in two separate Chinese populations.