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Biomedical subjects

S Kim

Publications and source records attributed to S Kim.

At least 937 records · Page 52Linked to original sources
PubMed1995

Incidence and position of the canal isthmus. Part 1. Mesiobuccal root of the maxillary first molar.

The mesiobuccal roots of 50 randomly selected maxillary first molars were examined to assess the incidence and position of the canal isthmus. Transverse serial sections of the apical 6 mm of each root were prepared in 1-mm increments. The apical side of each section was stained with methylene blue dye, viewed with a surgical operating microscope, and videotaped. Forty percent of the roots had one canal, whereas 60% had two canals. None of the sections had more than two main canals. The incidence of an isthmus was highest in the apical 3- to 5-mm levels. In teeth that had two canals, the 4-mm sections contained a complete or partial isthmus 100% of the time. The concept of a partial isthmus was presented. Failure to deal with the isthmus may explain why some posterior teeth do not heal completely following endodontic surgery.

Dental Pulp Cavity↗
PubMed1995

A rapid, direct test for zidovudine susceptibility in clinical isolates of human immunodeficiency virus type 1 (HIV-1) from infected children.

BACKGROUND: Existing phenotypic tests of antiretroviral susceptibility in clinical isolates of human immunodeficiency virus (HIV) are expensive and slow, and require passage of virus in cell culture with the possible consequence of selecting variants. OBJECTIVES: We sought to develop a rapid 14-day assay for zidovudine susceptibility of cell-associated HIV performed directly in patient blood samples. STUDY DESIGN: Twenty-three tests were performed prospectively in 21 children, and the results were compared with those of the AIDS Clinical Trials Group/Department of Defense consensus drug susceptibility assay (DSA) as well as certain clinical parameters. RESULTS: Five strains from ZDV-naive children were sensitive by the rapid test. Three were tested by DSA, and all were sensitive. Six strains from children who had received >/=24 months of ZDV were resistant by the rapid assay. Four of these strains were tested by the DSA, and all were shown resistant. The viral strains from children who received <24 months of therapy or who had switched from ZDV to other antiviral therapy exhibited variable sensitivity by both tests. Changes in CD4 cells in the subsequent 6 months, as well as weight gain during this time were both correlated to the results of the rapid test. The syncytium-inducing capacity of the virus strains was analyzed similarly. CONCLUSIONS: The rapid intracellular virus susceptibility assay is a test of drug sensitivity performed on HIV growing in cells obtained directly from an infected patient. The test has a two-week turn-around time and, in this preliminary report, gives results which correlate with both time on zidovudine and also subsequent CD4 cell changes.

Journal Article↗
PubMed1995

Leptin levels in human and rodent: measurement of plasma leptin and ob RNA in obese and weight-reduced subjects.

Leptin, the gene product of the obese gene, may play an important role in regulating body weight by signalling the size of the adipose tissue mass. Plasma leptin was found to be highly correlated with body mass index (BMI) in rodents and in 87 lean and obese humans. In humans, there was variability in plasma leptin at each BMI suggesting that there are differences in its secretion rate from fat. Weight loss due to food restriction was associated with a decrease in plasma leptin in samples from mice and obese humans.

Adult↗
PubMed1995

A phase II trial of intraperitoneal high-dose carboplatin and etoposide with granulocyte macrophage-colony stimulating factor support in patients with ovarian carcinoma.

Based upon results obtained in a Phase I study, we conducted a Phase II trial of high-dose CBDCA and etoposide administered via the intraperitoneal (IP) route in patients with ovarian cancer. CBDCA at a dose of 600 mg/m2 and etoposide at a dose of 400 mg/m2 were administered rapidly into the peritoneal cavity. The total dose of each agent was calculated and given daily over 3 days in amounts equal to one-third of the total dose. On day 1 of therapy, one-third of the dose was mixed in 2 liters of D5W and administered intraperitoneally as rapidly as possible. On days 2 and 3, one-third of the dose was mixed in 1 liter of D5W and administered similarly. GM-CSF was begun on day 4 as a subcutaneous injection at a dose of 500 micrograms/m2/day. A total 53 courses of treatment was administered to 18 patients; 9 of 13 patients (69%) with evaluable disease demonstrated evidence consistent with a partial response; however, the majority were response determined by a decrease in tumor marker (CA-125). One patient who had pathologic evidence of disease at second look laparotomy, but no measurable disease, was treated and shown at subsequent reexploration to have no further evidence of disease. This patient remains free of disease at 17+ months. The toxicity encountered in this trial was formidable, resulting in the removal of 78% of the patients from the study prior to completing 6 cycles of therapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1995

Poor renal uptake of Tc-99m DMSA and Tc-99m MDP in a patient with Fanconi syndrome and near normal glomerular filtration rate.

The authors present a patient with Fanconi syndrome who demonstrated poor renal uptake of Tc-99m DMSA and high urinary concentration of the tracer. Tc-99m DTPA imaging was normal and the creatinine clearance was only minimally decreased. These findings suggest that Tc-99m DMSA may be accumulated in the kidney by glomerular filtration and subsequent tubular reabsorption. A Tc-99m MDP bone scan showed faint renal uptake, as well as diffuse high skeletal uptake, particularly in the spine, demonstrating that the metabolic bone disease associated with Fanconi syndrome can be one of the causes of poor renal visualization on a bone scan.

Bone and Bones↗
PubMed1995

Soft tissue infection prophylaxis with gentamicin encapsulated in multivesicular liposomes: results from a prospective, randomized trial.

OBJECTIVES: Systemically administered antibiotic agents are not evenly distributed in the body, which frequently results in subtherapeutic regional drug concentrations, particularly in areas of poor vascularization, including wound sites. We have developed a lipid-based drug delivery system to provide prolonged levels of gentamicin in local tissues after local administration. Multivesicular liposomes are microspheres composed of lipid bilayer membranes surrounding multiple aqueous compartments that can contain drug. The preparation may be effective for the prevention and treatment of a variety of infections, including infections associated with indwelling vascular catheters. DESIGN: Prospective, randomized trial. SETTING: Animal laboratory. SUBJECTS: Mice, 6 to 12 wks of age, weighing 20 to 30 g. INTERVENTIONS: We administered 0.5 mg of gentamicin encapsulated in multivesicular liposomes to dorsal subcutaneous tissue in mice. Animals were inoculated with 10(5) to 10(7) colony-forming units (cfu) of Staphylococcus aureus 2, 4, 6, and 8 days later. The cfu/g of tissue values were determined 2 days after inoculation. MEASUREMENTS AND MAIN RESULTS: With a 10(7) cfu challenge, animals that received 2- and 4-day pretreatment with multivesicular liposome/gentamicin had a 4 log10 reduction in cfu/g of tissue compared with controls. When 10(5) cfu of Staphylococcus aureus were inoculated after 2- and 4-day pretreatment with multivesicular liposome/gentamicin, a 6 log10 reduction in bacteria colony-forming units was observed. CONCLUSION: Local injection of multivesicular liposome/gentamicin provides sustained drug concentrations in regional tissues that protect against a massive bacterial challenge for at least four subsequent days.

Animals↗
PubMed1995

Angiotensin II receptor blockade in TGR(mREN2)27: effects of renin-angiotensin-system gene expression and cardiovascular functions.

OBJECTIVE: To study the effect of angiotensin II receptor AT1 blockade on blood pressure, gene expression and pathomorphology of transgenic rats harbouring the mouse Ren-2 gene [TGR(mREN2)27], that develop fulminant hypertension while exhibiting suppressed components of the circulating renin-angiotensin system. DESIGN: TGR(mREN2)27 were treated orally with the newly developed AT1-specific angiotensin receptor antagonist Telmisartan, 4'-[(1,4'-dimethyl-2'-propyl[2,6'-bi-1H-benzimidazol]-1'-yl) methyl]-[1,1'-biphenyl]-2-carboxylic acid, in three doses (0.1, 1 and 3 mg/kg body weight) for 9 weeks. METHODS: The concentrations of the renin-angiotensin system components were analysed in plasma and tissues by radioimmunoassay. Messenger RNA levels for the angiotensinogen and renin genes were quantified by RNAase protection assay in several tissues. Heart hypertrophy and kidney morphology and function were monitored at the end of the treatment. RESULTS: In contrast to 0.1 mg/kg, 1 and 3 mg/kg Telmisartan normalized tail blood pressure measured once a week. Plasma renin and angiotensin II concentration increases were dose-dependent. The renin-angiotensin system genes in various cardiovascular organs were differentially regulated by angiotensin II receptor blockade. Treatment with Telmisartan stimulated angiotensinogen gene expression in the liver, kidney and heart, whereas it remained unchanged in the hypothalamus, thymus and adrenal gland. In the kidney, the expression of the endogenous, but not of the mouse Ren-2 gene, was increased in parallel to the renin concentration. Telmisartan reduced the severe glomerulosclerosis and proteinuria as well as cardiac hypertrophy observed in untreated TGR(mREN2)27 even with the lowest dose of 0.1 mg/kg, at which the blood pressure of the rats still exceeded 225 mmHg and the plasma renin-angiotensin system parameters were unchanged. CONCLUSION: From these experiments using a specific antagonist we can conclude that high blood pressure in TGR(mREN2)27 is angiotensin II-dependent. Furthermore, the expression of the renin-angiotensin system genes seems to be regulated not only by blood pressure and the plasma renin-angiotensin system but also by other, tissue-specific mechanisms. Pathomorphological changes in the kidney and in the heart do not seem to be caused by the systemic hypertension exclusively, but are also influenced by angiotensin II directly.

Adrenal Glands↗
PubMed1995

The guided tissue regeneration principle in endodontic surgery: one-year postoperative results of large periapical lesions.

Twenty patients with large endodontic lesions, which failed to respond to conventional endodontic therapy, were selected for this study. The lesions had a radiographic diameter of at least 10 mm, were removed by periradicular surgery, before retrofilling the apices with either super EBA or dessicated zinc oxide-eugenol. In 10 test sites large e-PTFE membranes (Gortex) were placed to cover the lesions, while at the control sites the lesions were not covered before resuturing. Radio-graphic analysis of the lesions at 3, 6, 9 and 12 months revealed that lesions covered with the membranes healed quicker than the control lesions, and that the quality and quantity of the regenerated bone was superior when membranes were used. Results of the study indicate that guided tissue regeneration (GTR) principles can be effectively applied to the healing of large periapical lesions, especially in through-and-through lesions.

Adult↗
PubMed1995

Expression of sarcoplasmic reticulum Ca2+ -ATPase mRNA in the hypertrophied heart of young spontaneously hypertensive rats.

1. Recent evidence indicates that cardiac hypertrophy induced by pressure overload is associated with a decrease in sarcoplasmic reticulum (SR) Ca2+ -ATPase of myocytes, which may contribute to a diastolic dysfunction of the heart by causing intracellular Ca2+ overload. To elucidate whether or not this is also the case in genetic hypertension, we examined cardiac mRNA levels of SR Ca2+ ATPase in 11 week old spontaneously hypertensive rats (SHR) by northern blot analysis. 2. Furthermore, to test the effects of short-term inhibition of the renin-angiotensin system on its expression, we treated 10 week old SHR with angiotensin-converting enzyme inhibitors (alacepril and imidapril) or an AT1 receptor antagonist (SC-52458) for 7 days. 3. Though the left ventricular weight of SHR was significantly higher than that of Wistar-Kyoto (WKY) rats (277 +/- 6 vs 237 +/- 4 mg/100 g bodyweight, respectively, P < 0.05), the level of SR Ca2+ -ATPase mRNA showed no difference between SHR and WKY at this age. 4. Moreover, the aforementioned three drugs did not at all affect the SR Ca2+ -ATPase expression of SHR. 5. Thus, the expression of SR Ca2+ -ATPase was not down-regulated in the heart of 11 week old SHR, and seemed not to be mediated by angiotensin AT1 receptor at this age. Since some evidence on pressure-overloaded cardiac hypertrophy indicate that the decrease in SR Ca2+ -ATPase expression occur in prominent hypertrophy and in the failured heart, further studies on cardiac SR Ca2+ -ATPase expression in more aged SHR will be required.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1995

Suppression of vascular transforming growth factor-beta1 and extracellular matrix gene expressions by cilazapril and nifedipine in hypertensive rats.

1. We investigated the protective effects of an angiotensin-converting enzyme inhibitor (ACEI) and a Ca antagonist on vascular injury in hypertension. 2. Thirteen week old stroke-prone spontaneously hypertensive rats (SHRSP) were orally given cilazapril (ACEI 10 mg per kg day) or nifedipine (Ca antagonist 30 mg kg per day) for 12 weeks. After the treatment, the aorta and superior mesenteric artery were excised, and subjected to the extraction of RNA. mRNA levels for the transforming growth factor-beta1 (TGF-beta1) and extracellular matrix components such as fibronectin (FN), collagen type I (CoI), type III (CoIII) and type IV (CoIV) and laminin, were measured by northern blot analysis, using each specific cDNA probe. 3. In the mesenteric artery of SHRSP, TGF-beta1 mRNA levels were increased compared with Wistar-Kyoto (WKY) rats, being accompanied by a significant increase in mRNA levels for FN, CoI, CoIII, CoIV and laminin. In the aorta, only TGF-beta1 and fibronectin mRNAs were increased in SHRSP, but collagen and laminin were not increased. 4. Both cilazapril and nifedipine, to similar extents, suppressed the above mentioned increased gene expressions in both mesenteric artery and aorta, being associated with the improvement of vascular hypertrophy. 5. These results suggest that TGF-beta1 may be responsible for smooth muscle cell hypertrophy and the increased deposition of extracellular matrix in hypertensive blood vessels. Both cilazapril and nifedipine may lessen hypertensive vascular thickening, by suppressing the gene expression of TGF-beta1 and extracellular matrix.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1995

Attenuation of adrenomedullin-induced renal vasodilatation by NG-nitro L-arginine but not glibenclamide.

1. The present study was conducted in order to elucidate the in vivo contribution of nitric oxide (NO) and the glibenclamide-sensitive potassium channel in the renal action of adrenomedullin in anaesthetized dogs. 2. Intrarenal arterial infusion of adrenomedullin (20 ng kg-1 min-1) elicited a pronounced increase in renal blood flow with no changes in systemic blood pressure. The renal vasodilator action of adrenomedullin was markedly attenuated by pretreatment with NG-nitro L-arginine (L-NOARG), but this was reversed by continuous infusion of L-arginine. 3. Pretreatment with glibenclamide almost completely blocked the renal vasodilatation induced by lemakalim, but had no effect on the renal vasodilator and diuretic action of adrenomedullin. 4. Intrarenal arterial infusion of adrenomedullin induced diuresis and natriuresis. Diuretic and natriuretic action of adrenomedullin was also attenuated by L-NOARG. L-Arginine partly reversed the effect of L-NOARG and adrenomedullin-induced diuresis and natriuresis. 5. These data indicate that the in vivo renal vasodilator action of adrenomedullin is mediated by the release of NO. The glibenclamide-sensitive potassium channel is not involved in the renal action of adrenomedullin, at least, not in anaesthetized dogs. Since the inhibition of L-NOARG of adrenomedullin-induced diuresis occurred concomitantly with the attenuation of the renal vasodilator action of adrenomedullin, direct involvement of NO in adrenomedullin-induced diuresis remains to be established.

Adrenomedullin↗
PubMed1995

An MR compatible flow simulator for intravascular pressure simulation.

An MR compatible flow simulator is described which generates physiologically realistic pressure and flow waveforms. The simulator is based on a servomotor-driven gear pump which produces pulsatile flow by modulation of the servomotor rotation rate. Operation of the simulator is under the control of a personal computer, which executes an iterative feedback loop to minimize errors between measured and desired pressure waveforms. The simulator is totally automatic, requiring only a few minutes of iteration to generate the desired pressure waveform. Accurate sinusoidal waveforms with frequencies up to 10 Hz have been generated using the simulator, with high-frequency contamination of the measured waveform at least 80 dB below the fundamental frequency. Aortic waveforms have been produced with realistic flow rates and pressure variations. The pump assembly is mechanically straightforward and can operate at an 8-m distance from the flow phantom to allow the device to be isolated from the MR magnet room.

Biophysical Phenomena↗
PubMed1995

Lipid-based slow-release formulation of amikacin sulfate reduces foreign body-associated infections in mice.

Treatment and prophylaxis of uncomplicated infections with standard systemic antibiotics are usually successful. However, standard systemic antibiotic therapy alone is frequently unsatisfactory in certain circumstances, such as the presence of a foreign body (FB), necrotic tissue, overwhelming bacterial inoculum, or poor vascular supply to the involved tissues. We have developed a lipid-based sustained release formulation of amikacin sulfate (DepoFoam encapsulated amikacin sulfate [DEAS]) as a biodegradable, locally injectable antibiotic for such circumstances. The encapsulated drug is released over 7 to 10 days. We tested the efficacy of this formulation in an FB infection model in which Teflon tubes (length, 1 cm; outside diameter, 1.6 mm) were implanted into the subcutaneous tissue in mice and the local site was inoculated with 0.87 x 10(7) CFU of Staphylococcus aureus 3 days later. Inoculation was followed by either no treatment or a local injection of DEAS, free amikacin sulfate, non-drug-containing DepoFoam, or systemic free amikacin sulfate. All drug applications contained 1 mg of amikacin. One group was implanted with the FB and left unchallenged with bacteria and untreated as a sterile control group. All animals were sacrificed 10 days following FB implantation. FBs were retrieved from tissues by an aseptic technique and incubated in liquid culture media for 7 days. Local wound tissue was excised and processed to determine the number of CFU per gram of tissue. Treatment with local or systemic free amikacin had no effect on the number of infected FBs or on the log CFU in wound tissue compared with the untreated or non-drug-containing DepoFoam group. Compared with local free amikacin therapy, the number of infected FBs was reduced from 86 to 25% (P=0.02) following treatment with DEAS, and log CFU per gram of tissue was significantly decreased from 4.8 +/- 0.9 to 1.3 +/- 0.6 (P<0.0005). DEAS may have clinical utility as locally injected antibiotic in certain infections.

Amikacin↗
PubMed1995

Optimizing conditions for the growth of Lactobacillus casei YIT 9018 in tryptone-yeast extract-glucose medium by using response surface methodology.

This study was undertaken to find optimum conditions of tryptone, yeast extract, glucose, Tween 80, and incubation temperature for the growth of Lactobacillus casei YIT 9018 and to assess the effects of these factors by use of response surface methodology. A central composite design was used as an experimental design for allocation of treatment combinations. A second-order polynomial regression model, which was used at first for analysis of the experiment, had a significant lack of fit. Therefore, cubic and quartic terms were incorporated into the regression model through variable selection procedures. Effects involving incubation temperature, yeast extract, glucose, and tryptone were significant, whereas the only significant effect involving Tween 80 was the interaction effect between temperature and Tween 80. It turned out that growth of L. casei YIT 9018 was most strongly affected by the incubation temperature. Estimated optimum conditions of the factors for growth of L. casei YIT 9018 are as follows: tryptone, 3.04%; yeast extract, 0.892%; glucose, 1.58%; Tween 80, 0%; incubation temperature, 35 degrees C.

Bacteriological Techniques↗
PubMed1995

Development of monoclonal antibodies against Hantaan virus nucleocapsid protein.

Forty-five hybridoma cell lines producing monoclonal antibodies against Hantaan virus, the etiologic agent of hemorrhagic fever with renal syndrome, were generated by fusion of P3-X63-Ag8.V653 myeloma cells with spleen cells of mice immunized with inactivated Hantaan virus vaccine. Among these, 38 antibodies were identified as binding to the 48-kDa nucleocapsid protein by immunoblot assay or radioimmunoprecipitation. Twenty-six of them were of the immunoglobulin G1 (IgG1), nine were of the IgG2a, and three were of the IgA isotype. According to cross-reactivities with other serotypes of the genus Hantavirus, the antibodies were classified into three groups: 6 antibodies specific to the Hantaan serotype (group I), 20 antibodies cross-reacting with Hantaan and Seoul serotypes (SR-11, Tchoupitoulas, and R22) (group II), and 12 antibodies cross-reacting with Hantaan, Seoul, and Prospect Hill serotypes (group III). None of the antibodies cross-reacted with the Puumala serotype. With a panel of antibodies of different cross-reactivities, serotypes of Hantavirus could be differentiated. Thirty-eight monoclonal antibodies against Hantaan virus nucleocapsid protein which have different cross-reactivities between serotypes were developed. These results confirmed the presence of multiple serotype-specific epitopes on the nucleocapsid protein of Hantaan virus, which can be utilized in differentiation of serotypes.

Animals↗
PubMed1995

Human T-lymphotropic virus type 1 in coastal natives of British Columbia: phylogenetic affinities and possible origins.

Human T-lymphotropic virus type 1 (HTLV-1) infection has been discovered recently in people of Amerindian descent living in coastal areas of British Columbia, Canada. DNA sequencing combined with phylogenetic analysis and restriction fragment length polymorphism (RFLP) typing of HTLV-1 strains recovered from these British Columbia Indians (BCI) was conducted. Sequence-based phylogenetic trees distributed the BCI isolates among the Japanese subcluster (subcluster B) and the geographically widely distributed subcluster (subcluster A) of the large HTLV-1 cosmopolitan cluster. Long terminal repeat (LTR) RFLP typing revealed three distinct, equally frequent LTR cleavage patterns, two of which were of previously recognized Japanese and widely dispersed cosmopolitan types. A third, new cleavage pattern was detected which may have arisen by recombination between two other HTLV-1 genotypes. Our results suggest multiple origins for HTLV-1 in BCI, which are equally consistent with (i) a cluster of recent sporadic infections, (ii) ancient endemic vertical transmission through Amerindian lineages, or (iii) both.

Base Sequence↗