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Biomedical subjects

R Kim

Publications and source records attributed to R Kim.

At least 55 records · Page 3Linked to original sources
PubMed2001

A pitfall in the survival benefit of adjuvant chemotherapy for node- and hormone receptor-positive patients with breast cancer: the paradoxical role of Bcl-2 oncoprotein (review).

The survival benefit of adjuvant chemotherapy in node-positive patients with breast cancer compared with surgery alone has been established. The survival benefit differs considerably between hormone receptor-positive and -negative patients, and it is believed that the effectiveness of adjuvant chemotherapy can be increased by hormonal therapy with tamoxifen. In the present review, we discuss the rationale behind the effectiveness of combination treatment with anticancer drugs and tamoxifen in terms of the paradoxical role of Bcl-2 in apoptosis in breast cancer. The survival benefit between receptor-positive and -negative patients was assessed using previous reports of randomized controlled studies for postoperative adjuvant chemotherapy in node-positive breast cancer. Tamoxifen induces the anti-apoptotic gene, Bcl-2, by its effect on estradiol (E2), via an E2-response element in the promotor region of Bcl-2. The efficicacy of chemoendocrine therapy was assessed in terms of the influence of tamoxifen on the effect of anticancer drugs. Adjuvant chemotherapy, including anthracycline and non-anthracycline based regimens, has an overall survival benefit in node-positive breast cancer, with a 23.5% reduction in the annual odds of recurrence and a 15% reduction in mortality (P<0.00001). A comparison of the reduction of the relative risk indicates that the survival benefit in receptor-negative patients is superior to that in receptor-positive patients by approximately 3-fold. Further, in contrast to receptor-negative patients, there is no additional benefit from paclitaxel over doxorubicin and cyclophosphamide (AC) in receptor-positive patients. The possible reasons that the chemotherapy benefit in receptor-positive patients is small and marginal are the following: i) concurrent treatment or pretreatment with tamoxifen can increase plasma E2 levels in premenopausal patients, thereby inducing Bcl-2 in residual cancer cells, which might decrease drug-sensitivity in combination with chemotherapy; ii) induction of Bcl-2 might be involved predominantly in the resistance to taxanes, the cytotoxic action of which targets Bcl-2. Co-treatment or pretreatment with tamoxifen for adjuvant therapy might decrease the efficacy of anticancer drugs, an effect that is mediated by induction of Bcl-2, especially in premenopausal patients with node-positive breast cancer. Treatment with anticancer drugs should be followed by treatment with tamoxifen to produce a survival benefit from combination therapy in receptor-positive patients.

Antineoplastic Agents↗
PubMed2001

Significance of lymphoscintigraphic mapping with Tc-99m human serum albumin and tin colloid in sentinel lymph node biopsy in breast cancer.

Sentinel lymph node biopsy (SLNB) in breast cancer is considered in order to spare node-negative patients from axillary lymph node dissection. To assess the clinical significance of lymphoscintigraphic mapping in SLNB, we analyzed the lymphatic drain to the sentinel lymph nodes (SLNs) in terms of the pattern and direction of the hot spot. Twenty-three breast cancer patients were enrolled for SLNB. Before surgery, lymphoscintigraphic mapping of SLN was performed using Tc-99m human serum albumin (HSA) and tin colloids, and the hot spot was marked. The Tc-99m HSA and tin colloids were subcutaneously injected above the tumor and peritumor sites, respectively, and lymphoscintigraphic scanning was monitored every 5 to 10 min, for up to 2 h after injection. The SLN was identified using a combination of a blue dye, indigocalmine, and a gamma probe during surgery. The hot spot pattern and direction of the lymphatic drains were evaluated in 21 of 23 cases. Two cases did not have a hot spot. Single, double, and multiple hot spots were observed in 12 cases (52.1%), 8 cases (34.7%), and 1 case (4.3%), respectively. The positions of the hot spots were: axillary (n=17, 80.9%), axillary and sternal (n=3, 14.2%), and phrenic (n=1, 4.7%). The sensitivity and specificity rates in SLNB were 66.6% and 100%, respectively, and the overall predictive rate was 85.7%. Lymphoscintigraphy produced false negatives in three cases (33.3%), including one on the phrenic side. Lymphoscintigraphic mapping with Tc-99m HSA and tin colloids is useful for determining the SLN, and avoiding a false negative. The pattern and direction of the lymphatic drain to the SLN in scintigraphy need to be considered for the elimination of axillary lymph node dissection in node-negative patients with breast cancer.

Adult↗
PubMed2001

The cost-effectiveness of doxazosin for the treatment of hypertension in type II diabetic patients in the UK and Italy.

The objective of this analysis was to assess the cost-effectiveness of achieving 'tight control' versus 'less tight control' of blood pressure, as defined in the UK Prospective Diabetics Study 38, in type II diabetic patients in the UK and Italy. The effect of including doxazosin in a 'tight control' combination therapy was analysed. Given doxazosin's positive impact on lipid levels in addition to its antihypertensive effect, it is hypothesised that treatment including doxazosin will reduce the incidence of macrovascular complications. For each country, a Markov model was constructed to simulate macrovascular outcomes of patients on various drug combinations. Transitional probabilities were based on the risk rates presented in UKPDS 38. Risk rates were adjusted for the ageing of the cohort and the lipid-lowering properties of doxazosin using Framingham risk equations. Incremental cost-effectiveness ratios ranged from 2224 Pounds to 4867 Pounds (US$3225-7057) per life-year saved for the UK and from L1.8-9.3 million (US$818-4159) per life-year saved for Italy. Doxazosin is a cost-effective agent when included in a combination therapy in the treatment of hypertension in the diabetic populations of the UK and Italy.

Antihypertensive Agents↗
PubMed2001

[A case of inoperable advanced gall bladder cancer responding to intra-arterial infusion of 5-fluorouracil (5-FU) and leucovorin (LV)].

The prognosis in cases of inoperable advanced gall bladder cancer is poor. We report here a case of inoperable advanced gall bladder cancer that responded to treatment with continuous intra-arterial infusion of 5-FU and bolus injection of LV for biochemical modulation. The patient was an 81-year-old woman, who visited a nearby clinic with the chief complaints of general fatigue and right lateral abdominal pain. A mass lesion which occupied from the dorsal surface of the liver to the pancreatic head was found by ultrasonography, and she was referred to our hospital for further diagnosis and therapy. The diagnosis was advanced gall bladder cancer of Stage IVa (S2, N3, P0, H0, Hinf1, Dinf1). For the selective arterial infusion of anticancer drugs, the patient underwent intra-arterial cannulation into the common hepatic artery, with a connecting subcutaneous port for arterial infusion therapy. The treatment schedule for 5-FU and LV therapy consisted of continuous infusion of 5-FU of 333 mg/m2 for 72 hr and bolus injection of LV of 20 mg/m2 3 times at 24 hr intervals. This treatment was repeated every 2 weeks. No side effects were observed after the first administration during hospitalization, so the treatment was continued up to 17 times on an outpatient basis. A tumor response was seen in the primary lesion, No. 8 and No. 16 lymph node metastases. A partial response was observed for 13 months and the overall survival was 15 months. These findings may imply that treatment with intra-arterial infusion of 5-FU and LV can be an effective chemotherapy for prolongation of survival in patients with inoperable advanced gall bladder cancer.

Aged↗
PubMed2001

Actual colonoscopy: what are the risks of perforation?

Recent studies have suggested that virtual colonoscopy (VC) and actual colonoscopy (AC) have similar efficacy for detection of polyps >6 mm. However, procedural risks with emerging technology such as VC need to be assessed before widespread implementation. We propose to demonstrate complication rates after AC that can be used for a comparative benchmark in VC. From 1994 to 1999 all patients undergoing AC who sustained perforation that required operation were analyzed for the mortality and complications. There were 26,162 consecutive colonoscopies that required 21 operations for perforation. Of these 16,948 (65%) colonoscopies were diagnostic and 9,214 (35%) were therapeutic with 11 (0.06%) and 10 (0.11%) operations respectively. Overall risk for colonoscopic perforation that requires operation was one in 1,246 (one in 1,541 for diagnostic and one in 921 for therapeutic). Five perforations were oversewn, 15 were resected (five with stoma), and one was drained. One patient died. There were two reoperations. Mortality was 0.006 per cent (one in 16,948) for diagnostic and zero for therapeutic colonoscopy. Overall risk for perforation that requires operation or mortality after AC is low. Virtual colonoscopists who propose screening and subsequent therapeutic interventions need to report high volume without complications as the perforation rate requiring operation was one in 1,246.

Colon↗
PubMed2001

[Current status and future perspectives on chemotherapy in patients with gastric cancer: can the clinical data from Japan lead to a standard international therapy?].

From a meta-analysis of clinical studies in Japan and the West, although no survival benefit for stage I gastric cancer was observed in patients who received postoperative adjuvant chemotherapy, the survival benefit for patients with stage II and III disease was small and marginal effect, respectively, since the odds ratios were between 0.80 and 0.82 with a 95% confidence interval of less than 1.0. Anticancer drugs used for combination therapy included mitomycin C, anthracyclines, alkylating agents, and 5-fluorouracil. Increased long-term survival and the prevention of peritoneal recurrence were found in some patients who received combination therapy with mitomycin C, 5-fluorouracil, and nonspecific immunomodulators such as PSK and OK-432. Regarding chemotherapy for advanced and recurrent cases, administration of biochemical modulators such as low-dose FP and the new dehydropyrimidine dehydrogenase inhibitory fluoropyrimidine agent S 1 resulted in increased response rates, improved quality of life, and prolongation of survival. The development of rigorous trials and personalized chemotherapy with molecular targeting are needed to achieve further survival benefit for patients with gastric cancer.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

[A new therapeutic approach to advanced and recurrent gastric cancer by TS-1].

In the present study, we demonstrate the treatment results of TS-1 on 22 gastric carcinoma patients (15 far advanced and 7 recurrent patients) from June 1999 to December 2000. TS-1 was administered at 75 mg/m2/day, twice daily per body for 28 days followed by a 14-day interval (1 cycle). Successful treatment was obtained in from 1 to 11 cycles, and we obtained 9 (47.4%) partial responses (PR), 7 stable disease (NC) and progressive disease (PD) among 19 evaluable patients. PR was obtained in 7 (58.3%) out of 12 primary lesions of the stomach. We also obtained 1 CR of liver metastasis and 4 PR of 9 distant lymph node metastases (44.4%). Moreover, malignant ascites disappeared in 4 (57.1%) out of 7 cases and PR was obtained in 3 (50%) out of 6 measurable cases of peritoneal disease. In addition, two patients had hydronephrosis which improved after 1 cycle of TS-1 treatment. The adverse effects observed were grade 3 bone marrow suppression in three cases, severe diarrhea in one case, one case of liver dysfunction and a few cases of nausea and vomiting. These results indicate that the oral tegafur compound, TS-1, is a new therapeutic tools for advanced and recurrent gastric carcinomas, especially peritoneal disease.

Administration, Oral↗
PubMed2000

Crystal structure of an intracellular protease from Pyrococcus horikoshii at 2-A resolution.

The intracellular protease from Pyrococcus horikoshii (PH1704) and PfpI from Pyrococcus furiosus are members of a class of intracellular proteases that have no sequence homology to any other known protease family. We report the crystal structure of PH1704 at 2.0-A resolution. The protease is tentatively identified as a cysteine protease based on the presence of cysteine (residue 100) in a nucleophile elbow motif. In the crystal, PH1704 forms a hexameric ring structure, and the active sites are formed at the interfaces between three pairs of monomers.

Amino Acid Sequence↗
PubMed2000

Differences in mutant p53 protein stability and functional activity in teniposide-sensitive and -resistant human leukemic CEM cells.

We examined p53 protein stability and DNA damage-induced p53-dependent responses in a human leukemic CEM cell line and two teniposide-resistant sublines, CEM/VM-1 and CEM/VM-1-5 ( approximately 40 and 400-fold resistant to teniposide, respectively). Although all cell lines contain the same p53 mutations at codons 175 (Arg-->His) and 248 (Arg-->Gln), the constitutive levels of p53 were progressively increased with the resistance of the cells to teniposide. By pulse-chase experiments, we found that the half-lives of mutant p53 protein were approximately 12, 17, and >30 h in CEM, CEM/VM-1, and CEM/VM-1-5 cells, respectively. The prolonged half-lives of p53 in these cells is consistent with the fact that the protein harbors the indicated mutations. Of note, however, is the fact that the increased p53 protein half-lives in the two drug-resistant cell lines corresponds to a proportional decrease in MDM2 protein levels but an increase in p53-MDM2 binding interactions. This suggests that MDM2-mediated p53 degradation may be altered in our leukemic cell lines. The DNA damage-induced p53 response is fully functional in the drug-sensitive CEM cells containing a mutant p53, but this pathway is attenuated in the drug-resistant cells. Specifically, while the mutant p53 was phosphorylated at serine-15 in response to ionizing radiation in all these cell lines, mutant p53 induction in response to teniposide or ionizing radiation and induction of the p53-target genes, p21 and GADD45 only occurred in the drug-sensitive CEM cells. As assessed by MTT cytotoxicity assay, CEM cells were also significantly more sensitive to ionizing radiation, compared to the drug-resistant cell lines, and this correlated with p53 induction. Collectively, these results suggest that changes in constitutive mutant p53 protein levels, p53-MDM2 binding interactions, and altered regulation of the DNA damage-inducible p53-dependent pathway may play a role in drug- and radiation-responsiveness in these cells.

Antineoplastic Agents↗
PubMed2000

Crystal structure of archaeal RNase HII: a homologue of human major RNase H.

BACKGROUND: RNases H are present in all organisms and cleave RNAs in RNA/DNA hybrids. There are two major types of RNases H that have little similarity in sequence, size and specificity. The structure of RNase HI, the smaller enzyme and most abundant in bacteria, has been extensively studied. However, no structural information is available for the larger RNase H, which is most abundant in eukaryotes and archaea. Mammalian RNase H participates in DNA replication, removal of the Okazaki fragments and possibly DNA repair. RESULTS: The crystal structure of RNase HII from the hypothermophile Methanococcus jannaschii, which is homologous to mammalian RNase H, was solved using a multiwavelength anomalous dispersion (MAD) phasing method at 2 A resolution. The structure contains two compact domains. Despite the absence of sequence similarity, the large N-terminal domain shares a similar fold with the RNase HI of bacteria. The active site of RNase HII contains three aspartates: Asp7, Asp112 and Asp149. The nucleotide-binding site is located in the cleft between the N-terminal and C-terminal domains. CONCLUSIONS: Despite a lack of any detectable similarity in primary structure, RNase HII shares a similar structural domain with RNase HI, suggesting that the two classes of RNases H have a common catalytic mechanism and possibly a common evolutionary origin. The involvement of the unique C-terminal domain in substrate recognition explains the different reaction specificity observed between the two classes of RNase H.

Amino Acid Sequence↗
PubMed2000

Crystal structure of a fibrillarin homologue from Methanococcus jannaschii, a hyperthermophile, at 1.6 A resolution.

Fibrillarin is a phylogenetically conserved protein essential for efficient processing of pre-rRNA through its association with a class of small nucleolar RNAs during ribosomal biogenesis. The protein is the antigen for the autoimmune disease scleroderma. Here we report the crystal structure of the fibrillarin homologue from Methanococcus jannaschii, a hyperthermophile, at 1.6 A resolution. The structure consists of two domains, with a novel fold in the N-terminal region and a methyltransferase-like domain in the C-terminal region. Mapping temperature-sensitive mutations found in yeast fibrillarin Nop1 to the Methanococcus homologue structure reveals that many of the mutations cluster in the core of the methyltransferase-like domain.

Amino Acid Sequence↗
PubMed2000

Zebrafish nma is involved in TGFbeta family signaling.

Bone morphogenetic proteins (BMP) are members of the TGFbeta superfamily of secreted factors with important regulatory functions during embryogenesis. We have isolated the zebrafish gene, nma, that encodes a protein with high sequence similarity to human NMA and Xenopus Bambi. It is also similar to TGFbeta type I serine/theronine kinase receptors in the extracellular ligand-binding domain but lacks a cytoplasmic kinase domain. During development, nma expression is similar to that of bmp2b and bmp4, and analysis in the dorsalized and ventralized zebrafish mutants swirl and chordino indicates that nma is regulated by BMP signaling. Overexpression of nma during zebrafish and Xenopus development resulted in phenotypes that appear to be based on inhibition of BMP signaling. Biochemically, NMA can associate with TGFbeta type II receptors and bind to TGFbeta ligand. We propose that nma is a BMP-regulated gene whose function is to attenuate BMP signaling during development through interactions with type II receptors and ligands.

Activin Receptors, Type I↗
PubMed2000

A c-fos/Estrogen receptor fusion protein promotes cell cycle progression and proliferation of human cancer cell lines.

c-fos is the prototypic member of a family of transcription factors that regulate many cellular processes, including proliferation. c-fos heterodimerizes with jun family members to form the AP-1 transcription factor complex which binds specific DNA recognition elements in the promoters of many genes. Following rapid induction in response to serum or growth factors, c-fos regulates expression of downstream target genes involved in cellular proliferation. Although much work has focused on activation of cell cycle regulatory genes by c-fos, less is known about negative regulation of gene expression by this transcription factor. The cyclin-dependent kinase (cdk) inhibitor p21(Cip1/WAF1) is a negative regulator of cdk activity, thereby impeding cell cycle progression. By sequence analysis, we identified a putative AP-1 element in the p21(Cip1/WAF1) promoter. To investigate how this site regulated p21(Cip1/WAF1) expression and mitigate external effects on c-fos expression, we used a c-fos/estrogen receptor (c-fosER) fusion construct in which this transcription factor is conditionally activated by estradiol. In the presence of estradiol, c-fosER downregulated p21(Cip1/WAF1) promoter activity. This inhibition was dependent on the putative AP-1 site. Activation of c-fosER induced cell cycle progression and proliferation in a manner similar to serum stimulation. We concluded that activation of c-fosER mediated transcriptional inhibition of p21(Cip1/WAF1) through a previously uncharacterized AP-1 site, revealing an important role for c-fos in negative control of cell cycle regulatory genes.

Cell Cycle↗
PubMed2000

An analysis of the therapeutic efficacy of protracted infusion of low-dose 5-fluorouracil and cisplatin in advanced gastric cancer.

To analyze the clinical efficacy of a protracted infusion of low-dose 5-fluorouracil (5-FU) and cisplatin (CDDP), a phase II study was performed in 36 patients with advanced gastric cancer. The treatment schedule of the low-dose administration of 5-FU and CDDP (FP) was a continuous infusion of 5-FU (250 mg/m2) for 28 consecutive days and a drip infusion of CDDP (3.5 mg/m2) for 5 consecutive days, followed by a 2-day interval each week in one cycle. The overall response rate was 47.2%. Of importance, the improvement in quality of life assessed by performance status (PS) and oral intake was 13.9% and 33.3%, respectively. The toxicity in low-dose FP treatment was less than grade 2, including gastrointestinal toxicities and bone marrow suppression, and this was tolerable during the treatment. The median survival time (MST) and 1-year survival rate were 8 months and 36.2%, respectively. In a pharmacokinetic analysis following the protracted infusion of low-dose FP, the plasma concentrations of 5-FU and CDDP were increased to about 120-130 ng/ml and 0.3-0.5 microg/ml on day 21 after the treatment, respectively. The plasma concentrations of 5-FU and CDDP were not significantly different between responders and non-responders. The tumor response to low-dose FP treatment was associated with the induction of apoptotic cell death and with the overexpression of apoptosis-related genes, such as Bax and Bcl-Xs, in cancer cells. These results indicate that the protracted infusion of low-dose FP could be a useful regimen for patients with advanced gastric cancer, in terms of the high response rate and low toxicity, possibly leading to the prolongation of survival and improvement in the quality of life.

Adolescent↗
PubMed2000

Inhibited neutrophil apoptosis: proteasome dependent NF-kappaB translocation is required for TRAF-1 synthesis.

Neutrophil (PMN) apoptosis regulates local and systemic inflammation during sepsis. Tumor necrosis factor receptor-associated factors (TRAFs) have been implicated as mediators of apoptosis; however, the signaling pathways for their production in stimulated PMN are unclear. We hypothesize that NF-kappaB translocation is necessary for the induction of TRAF-1 in PMNs with prolonged survival. Neutrophils were isolated from the blood of healthy volunteers by Ficoll gradient centrifugation and red blood cell sedimentation. Neutrophil NF-kappaB was inhibited with a proteasome inhibitor, PSI-I. Cells were treated with PSI-I (30 microM) or vehicle (DMSO 0.2%) for 50 min then incubated over an 18-h time course with LPS (10 to 1000 ng/mL), tumor necrosis factor alpha (TNFalpha) (2 to 20 ng/mL) or control media. In vitro apoptosis was quantified by propidium iodide FACS analysis. Total cellular TRAF-1 was detected by Western blot analysis of cell lysates. Steady state TRAF-1 mRNA was detected by RPA. NF-kappaB activity was determined by Western blot analysis for nuclear p65. Means and standard errors were calculated; data were analyzed by ANOVA. Lipopolysaccharide (LPS) and TNFalpha increased PMN nuclear p65 and steady state TRAF-1 mRNA. Apoptosis was inhibited by TNFalpha and LPS at 12 and 18 h (P < 0.01). Incubation of cells in the NF-kappaB inhibitor PSI-I blocked LPS and TNFalpha-induced inhibition of apoptosis (P < 0.05) and the induction of both nuclear p65 and TRAF-1 mRNA. These data demonstrate that inhibition of PMN apoptosis and TRAF-1 induction by LPS and TNFalpha is NF-kappaB dependent.

Apoptosis↗
PubMed2000

Prioritizing back injury risk in hospital employees: application and comparison of different injury rates.

To identify high risk areas for back injury in a large teaching hospital, we calculated standard injury rates and newly developed composite statistics for nursing and non-nursing work groups. Data were extracted from the hospital's workers' compensation database. The hospital-wide total injury rate was 4.6 reports per 100 full-time equivalents (FTE); Compensation Case Rate, 1.4 cases per 100 FTE; Compensation Severity Rate, 76 days lost per 100 FTE; and the Cost Rate, $3742 per 100 FTE. The Total Injury Reports Rate for nursing varied from 14.2 per 100 FTE for Intensive Care Unit (ICU) Nursing to 3.8 per 100 FTE for Pediatric Nursing. Non-nursing areas also demonstrated increased rates for back injury. Individual statistical rates ranked areas differently in risk, whereas composite statistical measures consistently ranked ICU Nursing, Buildings and Grounds, and Orthopedics/Neurological Nursing as the top three. Patient handling was the precipitating event in the majority of nursing back injuries, indicating the need for ergonomic intervention. The use of combined statistical measures provided a more integrative measure for describing and following back injury risk over time.

Absenteeism↗