Search PubMed⌕ Search

Biomedical subjects

H C Kim

Publications and source records attributed to H C Kim.

At least 199 records · Page 11Linked to original sources
PubMed1997

[Effects of 16-week dietary administration of 2-amino-3,8-dimethylimidazo[4, 5-f]quinoxaline in rats].

2-Amino-3,8-dimethylimidazo[4, 5-f]quinoxaline (MeIQx), a heterocyclic amine found in cooked meats, is carcinogenic in mice and rats at high doses. In order to examine the toxicity including preneoplastic changes at the lower doses, a total of 170 male Fischer 344 rats were administered MeIQx for 16 weeks at a dose of 100, 10, 1, 0.1, 0.01, 0.001 ppm or 0 ppm in the diet. The numbers of GST-P positive foci and BrdU-labeling indices in the liver were significantly increased by the dietary administration of 10 ppm and 1 ppm or more of MeIQx respectively, when compared with the basal diet-fed control rats. Aberrant cry p tfoci (ACF) were also significantly increased in the 100 ppm MeIQx group as compared to the control value. No histopathological changes indicating obvious toxicity of MeIQx were observed in the major organs other than the liver and large intestine. In conclusion, our results clearly indicate that MeIQx selectively targets the liver and large intestine of rats as organs for the toxicity, but dose not affect the other major organs at low doses.

Animals↗
PubMed1996

Reappraisal of eight representative carcinogenic and non-carcinogenic compounds in a new medium-term rat liver bioassay using D-galactosamine.

The carcinogenic potential of eight different compounds was assayed in a new medium-term carcinogenicity bioassay using D-galactosamine (DGA) as a non-surgical method to induce regeneration in place of partial hepatectomy (PH). Male rats were initially given a single i.p. injection (200 mg/kg) of diethylnitrosamine (DEN) and after 2 weeks on basal diet, received two i.p. injections of DGA (300 mg/kg) at the end of weeks 2 and 5. They were treated with one of the test compounds aflatoxin B1, benzo[a]pyrene, diethylstilbestrol, urethane, sodium saccharin, bucetin, D-mannitol and sodium chloride in the diet or basal diet alone for weeks 3-8. Carcinogenic potential was assessed by comparing the numbers and areas per cm2 of glutathione S-transferase placental form-positive (GST-P+) foci in the livers of treated animals with those of the control animals given DEN/DGA alone. Positive estimations of carcinogenicity were obtained for the hepatocarcinogens aflatoxin B1, diethylstilbestrol or urethane, and for the non-liver carcinogen benzo[a]pyrene. Negative values were shown in rats treated with the non-carcinogens, D-mannitol and sodium chloride. The two other non-liver carcinogens sodium saccharin and bucetin, also did not exert positive effects in the system. The present data are consistent with findings in previous medium-term bioassays using PH. Our results thus confirm that the present bioassay protocol with repeated administration of DGA instead of PH may offer a new and sensitive non-invasive method to screen large numbers of environmental carcinogens.

Animals↗
PubMed1996

Chemopreventive effects of 24R,25-dihydroxyvitamin D3, a vitamin D3 derivative, on glandular stomach carcinogenesis induced in rats by N-methyl-N'-nitro-N-nitrosoguanidine and sodium chloride.

The modifying effects of 24R,25-dihydroxyvitamin D3 [24R,25(OH)2D3], a vitamin D3 derivative, on glandular stomach carcinogenesis were investigated in male Wistar rats by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and sodium chloride exposure during the postinitiation phase. A total of 130 male 6-week-old rats was divided into five groups. Groups 1-3 (consisting of 30 rats/group) were given MNNG in drinking water at a concentration of 100 ppm and were simultaneously fed a diet supplemented with 10% NaCl for 8 weeks. They were fed a diet containing either 5.0 ppm (group 1) or 2.5 ppm (group 2) 24R,25(OH)2D3 or were kept on the basal diet alone (group 3) for the following 57 weeks. Rats in groups 4 and 5 were given 24R,25(OH)2D3, as were animals in groups 1 and 3, but did not receive the MNNG + NaCl treatment. The total incidence of combined atypical hyperplasias and adenocarcinomas in the glandular stomachs was significantly lower in group 1 (24%) than in group 3 (70%; P < 0.01). The mean numbers of atypical hyperplasias or adenocarcinomas of the glandular stomachs in groups 1 (0.31) and 2 (0.66) were also significantly decreased (P < 0.01 and P < 0.05, respectively) as compared to the group 3 value (1.21). Thus, the development of cancerous and precancerous lesions in the glandular stomach was decreased by exposure to 24R,25(OH)2D3 in a dose-dependent manner. Urinary calcium levels were increased by this vitamin D3 derivative (in line with the applied dose) when assayed at 10, 30, and 62 weeks, regardless of the MNNG + NaCl treatment The present results clearly indicate that 24,25(OH)2D3 exerts chemopreventive effects, possibly by influencing calcium pharmacodynamics, when given during the postinitiation phase of glandular stomach carcinogenesis in rats.

24,25-Dihydroxyvitamin D 3↗
PubMed1996

Concurrent presentation of erythrocytic and megakaryocytic aplasia.

A case of a patient presenting with idiopathic concurrent erythrocytic and megakaryocytic aplasia is reported. The patient's response to immunosuppressive therapy and her bone marrow pathology clearly suggest an immune mechanism. Based on the lack of suppression of erythroid colony growth, several mechanisms are postulated. Well-established molecular and genetic evidence, along with clinical observations, suggests that a relationship exists between the erythrocytic and megakaryocytic cell lines. This may be related to a common bipotential stem cell or common cell surface markers. This case provides strong clinical evidence to support this relationship.

Adult↗
PubMed1996

Benign gastric tumors. Minimally invasive approach.

BACKGROUNDS: Historically, major subsets of benign gastric tumors requiring surgical excision have required open laparotomy. METHODS: We have used laparoscopy to resect lesions in eight such patients. Lesion locations were gastroesophageal junction (one), gastric body (three), and pylorus (four). Four lesions were successfully located by instrument palpation. Six lesions were excised using gastrotomy, eversion of tumor, and resection, followed by stapled gastrotomy closure. The lesion at the posterior GE junction was evaluated through a gastrotomy and resected transgastrically. The two pyloric lesions were removed by laparoscopic distal gastrectomy and gastrojejunostomy. RESULTS: Procedure times were 55-210 min; oral feeding was instituted on postoperative day 1-5; patients were discharged 1-6 days postoperatively. CONCLUSIONS: Benign tumors of the stomach may be approached and resected laparoscopically; a transgastric, intra-organ approach is safe and efficient; laparoscopic distal gastrectomy is safe and technically feasible; patients have a shorter recovery interval and shorter postoperative hospital stay. Cautious progress in this field is recommended.

Aged↗
PubMed1996

Early results of laparoscopic surgery for colorectal cancer. Retrospective analysis of 372 patients treated by Clinical Outcomes of Surgical Therapy (COST) Study Group.

UNLABELLED: This study was undertaken to determine the early experience of the embers of the COST Study Group with colorectal cancer treated by laparoscopic approaches. METHOD: A retrospective review was performed of all patients with colorectal cancer treated with laparoscopy by the COST Study Group before August 1994. Tumor site, stage, differentiation, procedure completion, presence of recurrence (local, distant, trocar site), and cause of death were analyzed. RESULTS: A total of 372 patients with adenocarcinoma of the colon and rectum were treated by laparoscopic approach between October 1991 and August 1994 (170 men and 192 women): right colectomy, 170; sigmoid colectomy, 55; low anterior resection, 56; abdominoperineal resection, 44; left colectomy, 22; colostomy, 8; total colectomy, 6; transverse colectomy, 7; exploration, 2. Conversion to an open procedure was required in 15.6 percent of cases. Operative mortality was 2 percent. Tumor characteristics were as follows: TNM state: I, 40 percent; II, 25 percent; III, 18 percent; IV, 17 percent; Differentiation: well-moderate, 88 percent; poor, 12 percent; carcinomatosis, 5 percent. Local (3.6 percent) and distant implantation occurred in four patients (1.1 percent). Only one of these patients died a cancer-related death (Stage III at 36 months). Cancer-related death rates increased with increasing stage of tumor: I, -4 percent; II, 17 percent; III, 31 percent; IV, 70 percent. CONCLUSION: A laparoscopic approach to colorectal cancer results in early outcome after treatment that is comparable with conventional therapy for colorectal cancer. A randomized trial is needed to compare long-term outcomes of open and laparoscopic approaches with colorectal cancer.

Adenocarcinoma↗
PubMed1996

Synergistic benefits of combined technologies in complex, minimally invasive surgical procedures. Clinical experience and educational processes.

The new burden surgical technology must assume demands not only improved efficiency and reduced risk, but also diminished cost and resource utilization. To this end, we have instituted the use of multiple, sequential technologies in complex, minimally invasive procedures: laparoscopic gastric surgery (44 cases), spine procedures (38 cases), and colectomies (96 cases). The technologies include head-mounted display, 3-D optics, robotic arm, harmonic scalpel, and optical access trocars. The combined use of these technologies shortened operative times, diminished use of personnel, and as associated with no technical mishap. Surgeon concentration and control of the operative environment were increased. In an effort to promote combined use of technologies, a structured teaching process was designed and implemented. It required five (average) experiences for efficient, hands-on implementation of combined technologies. We conclude that combined use of sophisticated technologies is safe and efficient; is accomplished by structured, moderately intense educational experience; and diminishes cost and use of human resources.

Clinical Competence↗
PubMed1996

Long-term toxicity/carcinogenicity study of L-histidine monohydrochloride in F344 rats.

The long-term toxicity and carcinogenicity of histidine, an essential amino acid for most animal species, were examined in Fischer 344 (F344) rats. Groups of 50 males and 50 females were given L-histidine monohydrochloride (HMHC) in their diet at concentrations of 0 (control), 1.25 and 2.5% for 104 wk; these dose levels were selected on the basis of the results of a subchronic toxicity study, in which body weights were depressed and formation of sperm granulomas in the epididymis was histologically evident in males fed 5.0% HMHC. All surviving rats were killed at wk 107. Increases in red blood cell count, haemoglobin value and haematocrit level were observed in male rats given 2.5% HMHC. A variety of tumours developed in all groups, including the control group, but all the neoplastic lesions were histologically similar to those known to occur spontaneously in this strain of rats, and no statistically significant increase in the incidence of any tumor was found in the treated groups of either sex. Thus, it was concluded that, under the present experimental conditions, HMHC is not carcinogenic in F344 rats.

Administration, Oral↗
PubMed1996

A multicentre comparison of once-daily subcutaneous dalteparin (low molecular weight heparin) and continuous intravenous heparin in the treatment of deep vein thrombosis.

OBJECTIVES: To compare the efficacy and safety of the low molecular weight heparin (LMWH) dalteparin with unfractionated heparin (UFH) in the acute treatment of DVT patients who had not previously received UFH. DESIGN: An open randomized multicentre trial with blinded analysis of venograms. SETTING: Seven hospitals in Sweden, Finland and the USA. SUBJECTS: A total of 330 patients, of 20 years or older, with suspected DVT, verified using venography. INTERVENTIONS: Fixed-dose dalteparin (200 IU kg-1) given as a once-daily subcutaneous injection, or aPTT adjusted i.v. UFH infusion for 6 to 10 days. MAIN OUTCOME MEASURES: Change in Marder score in patients with confirmed DVT and two evaluable venograms; PE, bleeding events and follow-up. RESULTS: Marder scores improved in 51% (95% CI 42-60%) of 92 patients treated with dalteparin and in 62% (95% CI 53-70%) of 98 patients treated with UFH (P = 0.152). One dalteparin-treated patient had a PE confirmed by V/Q scan; another had progressive thrombosis with swelling in the affected limb. Bleeding complications occurred in six patients in each group. One patient treated with dalteparin and five treated with UFH died during the 6-month follow-up period as a result of underlying malignancy or heart disease. The 6-month recurrence rate was low with both treatments (dalteparin, 3/97; UFH, 2/103). CONCLUSIONS: Fixed-dose subcutaneous dalteparin given once daily from the start of treatment is of equivalent efficacy and safety to conventional UFH therapy in the routine management of DVT.

Adult↗
PubMed1996

Chronologic change of serum IgG antibody response in chickens reinfected with Cryptosporidium baileyi.

Eight 2-day-old SPF chickens were each inoculated orally with a single dose of 5 x 10(5) oocysts of Cryptosporidium baileyi, and immunoglobulin G (IgG) antibody responses were chronologically measured by indirect immunofluorescent antibody (IFA) assay. Anti-C. baileyi IgG antibody levels remained high (1:106.67 to 1:512.00) for at least 4 months with 330 days of a detectable period. Ten days after the negative conversion, each chicken was re-challenged with 1 x 10(7) oocysts of the same species. Subsequent infection in 340-day-old individuals caused sudden elevated IgG antibody levels and the titer peaked on day 28 postchallenge inoculation (PCI), at 1:1.024 with a 65 days of detection period. Chickens in primary infection showed oocyst shedding profiles, but did not exhibit any oocyst shedding before or after experimental reinfection.

Animals↗
PubMed1996

Robotic arm enhancement to accommodate improved efficiency and decreased resource utilization in complex minimally invasive surgical procedures.

Resource allocation, including manpower and other expenses, have limited the evolution of minimally invasive surgical procedures to provide humanism and to improve surgical care for patients. Robotic enhancement has been proposed as a mechanism to improve the cost-benefit relationship for patients. To this end, we have used the robotic arm enhancement to minimize resource and personnel utilization during minimally invasive procedures. Phase I of our study has included the use of the robotic arm in 24 laparoscopic hernia repairs, cholecystectomies, and nissen fundoplications with the surgeon as a solo surgeon, i.e., the primary surgeon is the only participant in the operative sterile field. The scrub nurse did not participate in the procedures. During this study, there were no technical mishaps, no complications related to the solo surgeon-robotic arm concept, and the operative times were statistically similar to equivalent procedures utilizing multiple personnel. The hernia repair is least complex and most amenable to solo surgery due to the use of only three access ports; cholecystectomy occasionally requires four access ports increasing its complexity to a measurable degree. Nissen fundoplication, however, requires five access ports and proved to be the most complex of the procedures to adapt successfully to solo surgery utilizing robotic arm enhancement. Phase II of our study has involved the use of a combination of technologically complex and sophisticated technology to improve outcomes in complex laparoscopic procedures. The head-mounted display, the robotic arm, and the harmonic scalpel have been used in 140 complex minimally invasive procedures; the procedures were laparoscopic spine surgery (24 cases), laparoscopic gastric surgery (28 cases), and laparoscopic colon resection (88 cases). The use of these sophisticated technologies added safety, improved versatility, and did not increase the length of the operative procedures. The use of multiple technologies had an additive effect on the benefits. There were no experiences in which the technologies contributed to a technical complication or an adverse result for the patients. However, the successful use of these technologies requires an in depth educational experience for the surgeon and for the operating room team. In a further effort to improve efficiency and control of the visual fields during minimally invasive surgery, we have implemented a prototype voice activation, head-directed control, and instrument tracking by robotic arm enhancement in order to control the visual field through computer programming. Prototype voice activation and deactivation also allows instruments to be used in the visual field for the surgical procedure while not being used for tracking of the visual field. Tracking with the instrument utilizing a color-coded tracking system, and the head-directed control system have both been 100% effective in our hands, have not induced errors in technical performance of procedures, and have shortened the time required for performance of specific procedural tasks. Further, this process improves versatility for the surgeon, increases concentration, reduces fatigue and does not interfere with the position of the surgeon. Areas for improvement which have been observed utilizing these techniques are (1) the use of appropriate and consistent voice activation terminology, (2) the proper positioning of the instrument tracking unit in the most appropriate locations on the video screen and on the instrument within the visual field, and (3) the appropriate use of head-directed control of the robotic arm. We have concluded from these experiences that the robotic technology will continue to reduce costs and minimize risk for patients undergoing minimally invasive surgical procedures; moreover, safety, versatility, and diminished use of resources will accrue utilizing the additive benefit of sequential sophisticated technologies requiring a simultaneous educational

Animals↗