Biomedical subjects

K J Han

Publications and source records attributed to K J Han.

17 recordsLinked to original sources

PubMed2006

The JAK2 V617F mutation in de novo acute myelogenous leukemias.

A missense somatic mutation in JAK2 gene (JAK2 V617F) has recently been reported in chronic myeloproliferative disorders, including polycythemia vera, essential thrombocythemia and myelofibrosis with myeloid metaplasia, strongly suggesting its role in the pathogenesis of myeloid disorders. As activation of JAK2 signaling is occurred in other malignancies as well, we have analysed 558 tissues from common human cancers, including colon, breast and lung carcinomas, and 143 acute adulthood leukemias by polymerase chain reaction -- single strand conformation polymorphism analysis. We found three JAK2 mutations in the 113 acute myelogenous leukemias (AMLs) (2.7%), but none in other cancers. The mutations consisted of two V617F mutations and one K607N mutation. None of the AML patients with the JAK2 V617F mutation had a history of previous hematologic disorders. This is the first report on the JAK2 gene mutation in AML, and the data indicated that the JAK2 gene mutation may not only contribute to the development of chronic myeloid disorders, but also to some AMLs.

Adult↗

PubMed1998

A new member of alpha 1-adrenoceptor-coupled G alpha h (transglutaminase II) family in pig heart: purification and characterization.

We previously reported an identification of a 77-kDa GTP-binding protein that co-purified with the alpha 1-adrenoceptor following ternary complex formation. In the present paper, we report on the purification and characterization of this GTP-binding protein (termed G alpha h5) isolated from pig heart membranes. After solubilization of pig heart membranes with NaCl, G alpha h5 was purified by sequential chromatographies using DEAE-Cellulose, Q-Sepharose, and GTP-agarose columns. The protein displayed high-affinity GTP gamma S binding which is Mg(2+)-dependent and saturable. The relative order of affinity of nucleotide binding by G alpha h5 was GTP > GDP > ITP >> ATP > or = adenyl-5'-yl imidodiphosphate, which was similar to that observed for other heterotrimeric G-proteins involved in receptor signaling. Moreover, the G alpha h5 demonstrated transglutaminase (TGase) activity that was blocked either by EGTA or GTP gamma S. In support of these observations, the G alpha h5 was recognized by a specific antibody to G alpha h7 or TGase II, indicating a homology with G alpha h (TGase II) family. These results demonstrate that 77-kDa G alpha h5 from pig heart is an alpha 1-adrenoceptor-coupled G alpha h (TGase II) family which has species-specificity in molecular mass.

Animals↗

PubMed1998

Phospholipase C-delta1 and oxytocin receptor signalling: evidence of its role as an effector.

Although the oxytocin receptor modulates intracellular Ca2+ ion levels in myometrium, the identities of signal molecules have not been clearly clarified. Our previous studies on oxytocin receptor signalling demonstrated that 80 kDa Ghalpha is a signal mediator [Baek, Kwon, Lee, Kim, Muralidhar and Im (1996) Biochem. J. 315, 739-744]. To elucidate the effector in the oxytocin receptor signalling pathway, we evaluated the oxytocin-mediated activation of phospholipase C (PLC) by using solubilized membranes from human myometrium and a three-component preparation containing the oxytocin receptor-Ghalpha-PLC-delta1 complex. PLC-delta1 activity in the three-component preparation, as well as PLC activity in solubilized membranes, was increased by oxytocin in the presence of Ca2+ and activated Ghalpha (GTP-bound Ghalpha). Furthermore the stimulated PLC-delta1 activity resulting from activation of Ghalpha via the oxytocin receptor was significantly attenuated by the selective oxytocin antagonist desGly-NH2d(CH2)5[Tyr(Me)2,Thr4]ornithine vasotocin or GDP. Consistent with these observations, co-immunoprecipitation and co-immunoadsorption of PLC-delta1 in the three-component preparation by anti-Gh7alpha antibody resulted in the PLC-delta1 being tightly coupled to activated Ghalpha on stimulation of the oxytocin receptor. These results indicate that PLC-delta1 is the effector for Ghalpha-mediated oxytocin receptor signalling.

Calcium↗

PubMed1998

Identification of a distinct molecular mass G alpha(h) (transglutaminase II) coupled to alpha1-adrenoceptor in mouse heart.

Our previous studies on alpha1-adrenoceptor signaling suggested that G alpha(h) family is a signal mediator in different species. To elucidate the species-specificity of G alpha(h) family in molecular mass, we used the solubilized membranes from mouse heart and the ternary complex preparations containing alpha1-agonist/receptor/G-protein. Binding of [35S]GTPgammaS and the intensity of the [alpha-32P]GTP photoaffinity labeled protein resulting from activation of the alpha1-adrenoceptor were significantly attenuated by the antagonist, phentolamine. The molecular mass of the specific GTP-binding protein was approximately 72-kDa; homologous with G alpha(h) (transglutaminase II) family. Furthermore, immunological cross-reactivity of ternary complex from mouse heart and purified G alpha(h) from rat, guinea pig, and bovine using anti-G alpha(h7) antibody showed that their molecular masses were distinctly different and approximately 72-kDa G alpha(h) from mouse heart was the lowest molecular mass. Consistent with these observations, in co-immunoprecipitation and co-immunoadsorption of the alpha1-adrenoceptor in the ternary complex preparation by anti-G alpha(h7) antibody, the G alpha(h) family protein tightly coupled to alpha1-adrenoceptor. These results demonstrate the species-specificity of G alpha(h) family in molecular mass, especially the lowest molecular mass in mouse.

Animals↗

PubMed1998

A case of CMV disease of the jejunum in a patient with non-Hodgkin's lymphoma.

CMV infection may occur anywhere in the gastrointestinal tract. Among the small intestine, ileum is the most common site of CMV disease and infection of jejunum is a rare one in patients with CMV gastroenteritis. Although rare, the reason why the recognition of this diagnosis is important is that it cause the lethal hemorrhage and perforation of gastrointestinal tract when its diagnosis and treatment was delayed. Rapid diagnosis are able to using the immunohistochemical stain in shell vial culture of infected specimen or peripheral neutrophils preparation in viremic patients within 8 to 36 hours. The treatment of choice is antiviral agent or surgical resection. We experienced a case of CMV disease of jejunum in patient with non-Hodgkin's lymphoma who showed severe ulceration in jejunum and massive intestinal hemorrhage, and he survived after successful treatment with segmental resection of jejunum and intravenous ganciclovir.

Adult↗

PubMed1994

Graft-versus-host disease--clinical and pathological analysis of 11 biopsy proven cases.

Graft-versus-host disease (GVHD) is a life threatening complication that may occur following allogenic bone marrow transplantation (BMT) in the patients with aplastic anemia, leukemia or genetic immunodeficiency. It has been known that GVHD occurs approximately 70% of recipients of BMT in western countries but no definite incidence has been reported in Korea. In our St. Mary's Hospital, GVHD occurs in about 30% of BMT recipients. Histopathologically the acute phase skin shows diffuse lymphocytic infiltrates in the upper dermis with extensive exocytosis. Scattered throughout the epidermis are many degenerated keratinocytes, which are often associated with one or more satellite lymphocytes (satellite cell necrosis). In the chronic phase, acanthosis, eosinophilic keratinocytes resembling colloid bodies and mononuclear cell infiltrates in the upper dermis are noted. We reviewed 5 cases of acute GVHD and 6 cases of chronic GVHD. All patients received allogenic BMT from Jan. 1, 1992 to July 1, 1993. Ten patients were male and one was female. The mean age was 34 (20-70). The pathologic diagnosis was 3 cases of CML, 2 of ALL, 2 of AML (FAB M2), 2 of aplastic anemia, 1 of CLL and 1 of AML (FAB M5). The interval from BMT to GVHD varied from 14 days to 4 years (median 220 days). The skin and GI tract were involved in all eleven cases. Ten cases were histologically proven by skin biopsies, and two cases by salivary gland and colonic biopsies, respectively. The histological findings of the skin, salivary gland and colonic biopsieds were described. Immunohistochemical stain of the skin was done using CD4, CD8, HLA DR and Leu 7 antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

Allogeneic bone marrow transplantation for the patients with hemopoietic stem cell disorders: CUMC experience.

Bone marrow transplantation from an HLA-identical sibling is increasingly used as a curative therapy for patients with hemopoietic stem cell disorders including acute leukemia, chronic myelogenous leukemia and severe aplastic anemia. Between March 1983 and March 1991, we performed 86 cases of allogeneic bone marrow transplantation (BMT) for the patients with hemopoietic stem cell disorders: 25 acute myelogenous leukemia (AML); 15 acute lymphoblastic leukemia (ALL); 20 chronic myelogenous leukemia (CML); and 26 severe aplastic anemia (SAA). Ten out of 25 AML are in disease free survival (DFS). The causes of death were recurrence of leukemia (12), acute GVHD (3), sepsis (1) and veno-occlusive disease (1). Nine of 15 ALL are in unmaintained remission. Thirteen out of 20 CML are in DFS. Among 26 SAA, 21 are enjoying DFS, but 1 died of engraftment failure, 3 of graft rejection followed by cytomegalovirus (1) and aspergillus pneumonia (1). Comparing the survival between standard [less than or equal to CR1: 9/14 (64%)] and high risk [greater than or equal to CR1: 1/11 (9%)] AML, our data suggest that preparative regimen for high risk AML was not potent enough to eradicate the minimal residual disease in advanced AML. Although our cases are limited and the follow-up period is short, our result of ALL [overall: CCR (60%), standard risk (adult less than or equal to CR1, children less than or equal to CR2; 8/11 (73%) and high risk; 1/4 (25%)] and CML [overall: 65%, CP; 9/10 (90%), AP; 4/6 (67%), BP; 0/4 (0%)] are optimistic. It is of our interest that the incidence of death related with IP (1/33: 3%) and with AGVHD 94/33: 12%) were much less than that of other's observation but the explanation for this still remains to be clear.

Acute Disease↗

PubMed1991

[A study mother-infant interaction and maternal identity in mother-infant dyads of premature and full-term infants].

The study was conducted to examine Mother-Infant interaction and Maternal identity in two groups, that is, premature infant and its mother and full-term infant and its mother. For this purpose, the data were collected from 24 sample groups (12 for premature dyads and the remaining 12 for full-term dyads) by using observation method and questionnaires during July 20 through September 30, 1987. The results are summarized as follows: 1. In terms of Mother-Infant Interaction, full-term dyads considerably stood out compared to that of premature dyads (u = 21, p less than 0.01). 2. In terms of Maternal Identity, though full-term dyads showed somewhat high results, there was not a significant difference between two groups. 3. There was not a significant correlation between Mother-Infant Interaction and Maternal Identity.

Female↗

PubMed1991

[A phenomenological study on mother-infant interacting behavior patterns relating to newborn infant feeding in Korea].

The purpose of this study was to describe mother-infant interacting behavior patterns related to newborn infant feeding and to explore the mother's cultural belief about their infant. The data collection was conducted by observation and interview. Twenty-five mothers and their newborn infants who were normally delivered and were also planned to breastfeed were comprised as the subjects of this study. All subjects were interviewed and observed individually at 1 to 5 days after the delivery at the hospital, mid-wife's clinic, Maternal Child Health Center and their home throughout the country from remote area to big city. The observation data were recorded with symbolic letter on a recording sheet newly developed as a result of preliminary study. The interview data were tape recorded and then recorded in narrative form. Mother-infant interaction behaviors in early-feeding period were analyzed based on 19 analytic sub-categories and their composing elements. Unit of analysis were mother, infant and mother-infant dyad. 8 analytic categories draw from the data. Each were preparation, instrument, interaction inducing, evaluation referred to mother's behavior, preparation, instrument, interaction inducing referred to infant's behavior and synchronic behaviors referred to mother-infant dyad. Frequencies of behavior items based on the categories were converted to percent. The result showed that in mother's preparation behavior, the breast condition of Korean mother can be an affecting factor for mother-infant interaction during feeding, and vocalization behavior was observed most frequently in interaction inducing behavior while the least frequent behavior observed was contacting. Subcultural characteristics of mother-infant interaction behaviors were analyzed for their relationships between groups of mothers who have lived in remote area vs urban area, and who were multipara vs primipara. Using a chi-square test, there were statistically significant relationships in the activity of psychological readiness in preparation behavior and the movement of extremities for the position of instrumental behavior in both groups. However, interaction inducing behaviors were not related with statistical significance in any set of groups. Accomplishment of marriage, bonding and emotional mediation of family members were the categories related to mother's cultural belief about the infant in aspect of functional values. Infant at birth is considered little more than a biological organism without social capabilities. Although the newborn infant is still be attached to his mother, he makes his mother extend her territoriality. The mother's interacting behavior toward her infant based on those beliefs appeared task oriented, separative behavioral series.(ABSTRACT TRUNCATED AT 400 WORDS)

Breast Feeding↗

PubMed1991

[A study on the change of the primipara mother-infant interaction by infant's age in months].

The intent of this longitudinal descriptive correlational study is to investigate the change of the mother-infant interactions over the periods of one month, three months and six months of the infant's age. This study is also intended to explore the interrelationships among three major factors--the perception of pregnancy, the mother-infant interaction and the maternal attitude. The samples participated are 36 pairs of mother and infant from two university hospitals in Seoul. A data collection was made, from October in 1988 to September in 1989, for each subject at five periods of time; prenatal period (after 36 weeks in pregnancy), postpartum two or three days, one month, three months and six months of infant's age. The research tools used in this investigation are Mother-Infant Play Interaction Scale (MIPIS), Prenatal Self-Evaluation Questionnaire and Cohler's Maternal Attitude Scale. Some of the findings are as follows; 1. There is a significant increase in the mother-infant interaction from one month to three months and six months of infant's age. The highest score of the mother-infant interaction during three periods is at the time of three months. 2. The primipara's mother-infant interaction is not affected by the demographic characteristics, such as age, education and vocation of mother, types of delivery, or sex of infant. 3. Among seven categories of the perception of pregnancy, the most positively perceived categories by primiparas are acceptance of pregnancy and identification of a motherhood role; whereas the negative ones are preparation for labor, concern for well-being of self and baby, and fear of pain, helplessness and loss of control in order of negativity. 4. There is no significant relationship between the perception of pregnancy and the mother-infant interactions. 5. There is no significant change in the maternal attitude over the period of one month, three months, and six months of infant's age. 6. There is no significant relationship between the maternal attitude and the mother-infant interactions. 7. The significant relationships are found between the perception of pregnancy and maternal attitude, especially in the categories of concern for well-being of self and baby, acceptance of pregnancy, identification of a motherhood role, fear of pain, helplessness and loss of control, and relationship with husband. In conclusion, it is confirmed that primipara's mother-infant interactions change over time period, and that perception of pregnancy and the maternal attitude do not affect the mother-infant interactions despite a significant relationship between those two variables.(ABSTRACT TRUNCATED AT 400 WORDS)

Age Factors↗

PubMed1988