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Biomedical subjects

M Kim

Publications and source records attributed to M Kim.

At least 271 records · Page 15Linked to original sources
PubMed1997

[A case of bilateral upper urinary tract tumors after radical cystectomy].

We report a case of bilateral upper urinary tract tumors after total cystectomy. A 67-year-old male with multiple bladder tumors underwent total cystectomy and ileal conduit urinary diversion. Pathological diagnosis was transitional cell carcinoma, grade 3 (G3), pT1b. Followup urinary cytology continued to be negative. Percutaneous antegrade pyelography revealed multiple bilateral upper urinary tract tumors 21 months post-operatively. Bilateral nephroureterectomy and resection of ileal conduit were performed. Pathological examination revealed transitional cell carcinoma, G3 in bilateral pelvis and ureter. Routine careful examination is necessary after total cystectomy.

Aged↗
PubMed1996

Erythropoietin: physico- and biochemical analysis.

A hormone, erythropoietin, mainly produced in adult kidneys and fetal livers, acts on bone marrow erythroid progenitor cells to regulate the production of erythrocyte in mammals. As a result, the oxygen carrying capacity of blood increases and the increased oxygen supply raises the cardiac function and physiological working capacity. Erythropoietin is possibly misused by athletes in sports for the purpose of improving performance. Presently there is no discernible and specific method to identify erythropoietin administration for doping control. To address this practical problem, this paper presents a summary of the applications of analytical biotechnology, especially the structural characterization of erythropoietin.

Animals↗
PubMed1996

Ischemia increases the angiogenic potency of basic fibroblast growth factor (FGF-2).

The aim of this study was to investigate the angiogenic response to exogenously administered basic fibroblast growth factor (FGF-2) in normal and ischemic skin, using the hairless mouse ear microcirculatory model. The hairless mouse ear is a well-established model for in vivo studies of skin microcirculation. Using this model, angiogenesis- and angiogenesis-associated changes in the microcirculation can be directly and continuously viewed and quantified in a variety of different experimental settings. To create ischemia in the mouse ear, all but one of the three to four feeding vessels nourishing the ear were ligated 3 days prior to a local subdermal injection of FGF-2 (9.3 + 1-0.5 mm/mm2) or saline into the dorsum of the ears. Angiogenesis was quantified by direct observation, at high magnification, of the injection site where increases in total vessel length (TVL) were measured repeatedly over 18 days following injection. We found a significant (P < 0.01) increase in TVL in normal and ischemic ears injected with FGF-2. Saline injection also induced a significant increase in TVL in ischemic ears. However, the angiogenic response to FGF-2 in ischemic ears was significantly stronger than saline alone in ischemic ears or saline or FGF-2 in normal ears. This response could be used clinically to accelerate angiogenesis and thus increase perfusion in ischemic tissue.

Animals↗
PubMed1996

Silent ischemic cardiomyopathy and left coronary ostial stenosis secondary to radiation therapy.

A 55-year-old woman presented with profound congestive heart failure 23 years following mediastinal radiation. Ejection fraction (EF) was 35%. Symptoms markedly improved and EF increased to > 55% following saphenous vein bypass for > or = 80% ostial left main stenosis. Radiation therapy, a known risk factor for coronary atherosclerosis, may present with reversible severe silent ischemia.

Coronary Artery Bypass↗
PubMed1996

Shielding against galactic cosmic rays.

Ions of galactic origin are modified but not attenuated by the presence of shielding materials. Indeed, the number of particles and the absorbed energy behind most shield materials increases as a function of shield thickness. The modification of the galactic cosmic ray composition upon interaction with shielding is the only effective means of providing astronaut protection. This modification is intimately connected with the shield transport properties and is a strong function of shield composition. The systematic behavior of the shield properties in terms of microscopic energy absorption events will be discussed. The shield effectiveness is examined with respect to conventional protection practice and in terms of a biological endpoint: the efficiency for reduction of the probability of transformation of shielded C3H10T1/2 mouse cells. The relative advantage of developing new shielding technologies is discussed in terms of a shield performance as related to biological effect and the resulting uncertainty in estimating astronaut risk.

Aluminum↗
PubMed1996

Pectin with low molecular weight and high degree of esterification increases absorption of 58Fe in growing rats.

Effects of pectins with different degrees of esterification (DE) and molecular weights (MW) on iron bioavailability were investigated in healthy growing rats by following erythrocyte incorporation of a dose of 58Fe. Rats were fed a control diet for 8 d and then deprived of food for 16 h. Two hours after the start of feeding iron-deficient diets, with or without pectin (80 g/kg diet), a dose of FeSO4 rich in 58Fe (60.28%) was intubated into the stomach; rats were then allowed to feed for an additional 4 h before withdrawal of food for 10 h. Rats were then fed iron-adequate diets for 9 d. The pectins differed in DE and MW, respectively, as follows: P-A (73%, 860,000), P-B (75%, 89,000), P-C (22%, 1,260,000) and P-D (24%, 114,000). Rats fed pectin-free diet with free access to food or restricted to the same quantity consumed by a respective pectin group served as controls. Iron absorption was 48% in the control group and 57% in rats fed P-B. Rats fed P-B had higher (P 2 < or = 0.05) serum iron, transferrin saturation, hematocrit and liver and spleen iron than the control group or the group fed P-C. These indices, except for transferrin saturation, were also higher In rats fed P-A and P-D compared with those fed P-C and controls, but to a lesser extent than in rats fed P-B. The data indicate that bioavailability of dietary non-heme iron was enhanced when pectin of low MW and high DE was added to the diet. This improvement was not evident with pectins having high MW and/or low DE.

Absorption↗
PubMed1996

Absorption of polyethylene glycol oligomers (330-1 122 Da) is greater in the jejunum than in the ileum of rats.

Intestinal permeability to polyethylene glycols (PEG) was measured simultaneously in jejunum and ileum of anesthetized rats. Using a mixture of PEG (400, 600 and 1,000), which contained oligomers in the molecular weight (MW) range from 330 to 1122 Da, the MW permeability dependence of the rat small intestine was examined, employing an in situ recirculation perfusion technique. Individual oligomers of PEG were determined by HPLC with refractive index detection. Based on loss of oligomer from the reservoir, the permeabilities of the jejunum and ileum exhibited similar molecular weight dependencies. The apparent permeabilities were inversely proportional to approximately MW2 in both jejunum and ileum (r = 0.99, P < 0.05). In the range studied, a distinct molecular weight cutoff was not identified at either site. Over the molecular weight range from 330 to 1122 Da (and corrected for the length of each segment) the apparent permeability (Papp) of PEG ranged from 29.54 +/- 0.51 (mean +/- SEM, n = 5) to 1.69 +/- 0.08 microns/min in the jejunum, and from 18.97 +/- 0.47 to 0.74 +/- 0.05 microns/min in the ileum, indicating that the absorption of PEG oligomers is significantly greater in the jejunum than in the ileum (P < 0.05). A near constant ratio of jejunal/ileal permeabilities of 1.6 for the various oligomers (MW range from 330 to 990 Da) suggested that the major difference in the two sites is in the number, rather than the size distribution of the aqueous filled channels, possibly due to a difference in effective surface area for absorption.

Animals↗
PubMed1996

The water-soluble extract of chicory reduces glucose uptake from the perfused jejunum in rats.

Among the components of dietary fiber, the soluble fibers have been found to impair glucose absorption. Little is known, however, about the mechanism of this effect. The direct action of soluble fibers (chicory water-soluble extract and inulin) on the intestinal absorption of glucose was investigated in gutperfused rats. After equilibrium, both jejunal and ileal segments were simultaneously perfused with an isotonic electrolyte solution (pH 7.4) containing glucose (10 mmol/L) and chicory water-soluble extract (chicory extract) or inulin (10 g/L). Each test or control solution was perfused in random sequence, with perfusion times of 30 min. Chicory extract or inulin in the perfusate (10 g/L) inhibited the absorption of glucose from jejunum (P < 0.05). The observed changes in glucose and water absorption caused by chicory extract or inulin were reversible after switching to a fiberfree perfusate. Additionally, net water absorption changed to secretion upon addition of chicory extract or inulin. These results suggest that the reduction in intestinal absorption of glucose observed after perfusion of chicory extract or inulin may be caused by viscosity-related increases in mucosal unstirred layer thickness.

Animals↗
PubMed1996

The teaching matrix: a tool for organizing teaching and promoting professional growth.

Despite barriers of limited time and lack of formal preparation for teaching, physician-teachers want to do a good job in the classroom. However, without appropriate feedback or self-reflection, physician-teachers have no systematic way to think about their role both in what students learn and in how well they understand important information. With this in mind, the authors developed a model, the Teaching Matrix, designed to encourage clinician-teachers to reflect on their teaching before, during, and after each teaching session. The Matrix helps teachers to address five central questions: Who am I teaching? What am I teaching? How will I teach it? How will I know if the students "got it"? And how will I improve my teaching for the next time? In this paper, the authors describe how the Teaching Matrix may be used as a tool for planning actions, as a "suggestion box" of ideas, advice, and questions, and, most importantly, as a guide to systematic reflection on teaching.

Education, Medical, Undergraduate↗
PubMed1996

Cytomegalovirus infection in human immunodeficiency virus type 1-infected children.

BACKGROUND: Cytomegalovirus (CMV) is a frequent opportunistic infection in human immunodeficiency virus type 1 (HIV-1)-infected children. The interactions of CMV and HIV-1 in coinfected children are not well-characterized. OBJECTIVE: To evaluate the prevalence of asymptomatic CMV infection and symptomatic CMV disease and to assess the influence of CMV on clinical and laboratory markers of HIV disease progression in CMV-coinfected children. METHODS: Serial urine CMV cultures were performed on 500 children (131 HIV-1-infected (HIV+), 129 seroreverters born to HIV-infected mothers, and 240 HIV-uninfected (HIV-)). The clinical, immunologic and virologic data of 131 HIV+ children were analyzed. RESULTS: CMV was recovered in 40 of 131 HIV+ (31%), 22 of 129 seroreverters (17%) and 30 of 240 HIV- (13%) children. Of the 40 HIV+ children with CMV coinfection, 7 developed symptomatic CMV disease (17.5%) including chorioretinitis (3), colitis (2) and pneumonitis (2). The HIV+ children with symptomatic CMV disease had significantly lower mean CD4+ T lymphocyte proportions (17% vs. 26%; age-adjusted P = 0.013) and greater HIV p24 antigen concentrations (329 pg/ml vs. 57 pg/ml; age-adjusted P = 0.13) than HIV+ children with asymptomatic CMV infection. In a subset of children coinfected with CMV before 6 months of age (n = 11), 5 (45%) developed symptomatic CMV disease, and 4 of these 5 children died within 10 months of diagnosis of CMV disease. At the time of the first positive CMV culture in these children, mean CD4+ T lymphocyte proportions did not differ according to the presence or absence of CMV-related symptoms (symptomatic CMV+, 21% vs. asymptomatic CMV = 38%; P = 0.14). In HIV+ children with symptomatic CMV disease, p24 antigen concentrations were greater than in those with asymptomatic CMV infection (461 vs. 190 pg/ml, P = 0.06). CONCLUSIONS: Symptomatic CMV disease occurred in young CMV-coinfected children with low CD4+ lymphocytes and elevated HIV p24 antigen concentrations. Whether progressive immunodeficiency allows the emergence of CMV disease or CMV infection causes more rapidly progressive HIV-1 disease or whether there is a more complex relationship remains to be determined.

Age Factors↗
PubMed1996

Prefabricated jejunal free-tissue transfer for tracheal reconstruction: an experimental study.

Reconstruction of long-segment tracheal defects is a problem for the reconstructive surgeon. Difficulties arise with the use of prosthetic materials because of their propensity for infection and extrusion. Autologous tissue is limited by poor structural characteristics and technical complexity. We propose a simple composite bioprosthesis that, through a process of prefabrication and subsequent neovascularization, may provide a functional tracheal analogue superior to existing forms of reconstruction. Ten rats had composite flaps constructed by combining an isolated, perfused, mucosectomized segment with an outer covering of a ring-reinforced woven Dacron vascular graft. This unit remained in the intraabdominal milieu for 20 days and was then inspected for viability, incorporation of jejunum and graft, flexibility, and tolerance to negative pressure. Seven experimental animals survived the initial phase. The jejunal bioprostheses in all cases tolerated negative pressures to -200 mmHg, rotation of 180 degrees, and flexion to 90 degrees without collapse of the graft segments. Vascular casts and standard histologic examination showed neovascularization of the Dacron graft and dense fibrovascular ingrowth into the interstices of the graft. We conclude that prefabrication utilizing autologous and prosthetic components to create a single axial flap for transfer is a feasible solution to long-segment tracheal reconstruction. Neovascularization permeates the full thickness of the prosthetic component and is accompanied by dense fibrous ingrowth during the delay period. This neotracheal analogue also possesses structural characteristics similar to those of the native trachea and a durable submucosal layer that can support ingrowth of epithelium.

Animals↗
PubMed1996

Current treatment of cerebral metastasis.

Brain metastasis from systemic cancer remains a significant source of morbidity and mortality. Current treatment modalities include surgery, whole brain radiation, radiosurgery, brachytherapy, chemotherapy, and other experimental methods such as hyperthermia, hormonal therapy, and the use of biological modifiers. In this article we review and evaluate recent developments in these treatment modalities for the management of cerebral metastasis.

Brachytherapy↗
PubMed1996

Passive immunity against diarrhoea.

Passive immunity against a variety of respiratory and gastrointestinal pathogens has recently been increasingly used clinically, and oral administration of antibodies of both human and non-human origin has been tried both for prophylaxis and treatment of infections. Although the former type of therapy has been shown to be effective, data on the latter are still scarce. This commentary focuses on recent studies on successful oral therapeutic administration of bovine immunoglobulins.

Animals↗
PubMed1996

Case of a parathyroidectomized patient observed longitudinally by ultrasonography. Relationship between the growth rates and 1,25-dihydroxyvitamin D3 receptor contents in the parathyroid glands.

Parathyroid glands enlarge gradually with the progression of secondary hyperparathyroidism. The significance of down-regulation of the 1,25-dihydroxyvitamin D receptor (VDR) in parathyroid glands has been emphasized. Here we report a case in whom the relationship between the growth rates of the parathyroid glands and their VDR content was examined. A 36-year-old man, who had been hemodialyzed for 8.8 years because of chronic renal failure due to chronic glomerulonephritis, developed severe secondary hyperparathyroidism. The first ultrasonographic examination of the parathyroid glands, performed 10 months before parathyroidectomy, revealed that the sizes of the right upper (RU) and left upper (LU) glands were 10 x 8 x 5 and 14 x 10 x 9 mm3, respectively, although the right lower (RL) and left lower (LL) glands were not detected. The second ultrasonographic examination performed 5 days before PTX revealed that the RU gland had enlarged up to 24 x 12 x 10 mm3, while the LU gland remained unchanged at 16 x 9 x 8 mm3. At this time, the sizes of the RL and LL glands were determined only in the longitudinal section to be 10 x 5 and 4 x 3 mm2, respectively. In the excised specimens, the sizes and weights of the RU and RL glands were 25 x 10 x 9 mm3 and 1,950 mg and 17 x 10 x 8 mm3 and 1,160 mg, respectively, while those of the LU and LL glands were 16 x 10 x 7 mm3 and 850 mg and 9 x 8 x 7 mm3 and 350 mg, respectively. Histopathologic study demonstrated that the RU and RL glands exhibited nodular hyperplasia, while the LU and LL glands exhibited diffuse hyperplasia. Using a ligand binding assay, the VDR content of the rapidly growing RU and RL glands were significantly reduced to 32.6 +/- 9.6 and 32.7 +/- 5.2 fmol/mg protein, respectively, as compared to that of the LU gland with no significant proliferating activity (111.8 +/- 0.8 fmol/mg protein). It is of great interest that the smallest LL gland, which showed some proliferating potential in spite of a histologic pattern of diffuse hyperplasia, has a VDR content of 41.0 +/- 2.6 fmol/mg protein. In summary, it was implied from this case that the VDR content in the parathyroid gland might reduce as the growth rate of the parathyroid gland increases and, furthermore, that the VDR content seems to depend to some degree on the histopathologic pattern rather than on gland weight.

Adult↗
PubMed1996

Effect of hypertension on aortic root size and prevalence of aortic regurgitation.

Although early reports suggested that hypertension predisposed to aortic root enlargement and consequent aortic regurgitation, more recent pathological and M-mode echocardiographic studies have not found an association between hypertension and aortic enlargement when age is considered. These discrepancies may partially reflect methodological shortcomings in the accuracy and reproducibility of aortic and blood pressure measurements. Therefore, we measured two-dimensional echocardiographic diameters of the aortic root at four locations and compared findings with ambulatory and resting blood pressures and measures of body size in 110 normotensive and 110 hypertensive men and women matched for age and sex. Aortic diameters at the anulus (2.41 +/- 0.29 versus 2.34 +/- 0.24 cm, P = .06) and sinuses (3.47 +/- 0.44 versus 3.37 +/- 0.36 cm, P = .08) were marginally higher, whereas diameters at the supra-aortic ridge (2.94 +/- 0-38 versus 2.81 +/- 0.32 cm, P < .01) and ascending aorta (3.26 +/- 0.45 versus 3.11 +/- 0.32 cm, P < .01) were significantly increased in hypertensive subjects. Aortic diameters increased with increasing quartiles of diastolic and systolic pressures, particularly at the supra-aortic ridge and ascending aorta. In multivariate analyses, blood pressure remained an independent determinant of distal aortic diameters after body size and age were considered. Aortic regurgitation was seen in 5 normotensive and 7 hypertensive subjects and did not differ in severity. Thus, hypertension is associated with a slight increase in aortic root size, most notably of the supra-aortic ridge and proximal ascending aorta. Although dilatation at the commissural attachment might be expected to predispose to an increase in aortic regurgitation, we did not detect such a difference in this population of healthy, asymptomatic individuals.

Adult↗
PubMed1996

Inhibitory effects of green tea polyphenols on growth and cellular adherence of an oral bacterium, Porphyromonas gingivalis.

Effects of polyphenolic compounds isolated from green tea (Camellia sinensis) on the growth and adherence of Porphyromonas gingivalis onto human buccal epithelial cells were investigated. Green tea polyphenols, especially (-)-epigallocatechin gallate (EGCg) which is a dominant component of tea polyphenols, completely inhibited the growth and adherence of P. gingivalis onto the buccal epithelial cells at concentrations of 250-500 micrograms/ml. Among the polyphenolic compounds, (-)-epicatechin gallate (ECg) and (-)-gallocatechin gallate (GCg) were effective next to EGCg in these activities. On the other hand, (+)-catechin (C(+)), (-)-epicatechin (EC), (+)-gallocatechin (GC), and (-)-epigallocatechin (EGC) had very much less activity. These results indicate that the inhibitory effect on the adherence of P. gingivalis onto the buccal epithelial cells is attributed to the presence of the galloyl moiety, which is ester-linked with the 3-OH of the catechin moiety in the polyphenolic compounds.

Bacterial Adhesion↗
PubMed1996

Abnormal serum porphyrin levels in patients with the acquired immunodeficiency syndrome with or without hepatitis C virus infection.

OBJECTIVE: To define the contributions of human immunodeficiency virus (HIV) and hepatitis C virus infections to the development of porphyria cutanea tarda. DESIGN: Analysis of serum porphyrin levels in a cohort of 167 subjects. Serum samples were divided into 4 groups corresponding to the status of HIV and hepatitis C virus infections: positive-positive, positive-negative, negative-positive, and negative-negative. SETTING: Serum samples positive for HIV were obtained from the serum bank of an acquired immunodeficiency syndrome-HIV research center, and HIV-negative samples were obtained from a regional blood center. MAIN OUTCOME MEASURES: Spectrofluorometric measurement of serum porphyrin levels. RESULTS: The median values of porphyrin were 2.31 nmol/L (interquartile range [difference between the 25th and 75th percentiles]: 4.55) in the positive-positive group, 1.99 nmol/L (interquartile range: 1.63) in the positive-negative group, 1.31 nmol/L (interquartile range: 1.58) in the negative-positive group, and 1.14 nmol/L (interquartile range: 0.92) in the negative-negative group. The fluorescence emission spectra of samples with elevated porphyrin levels were identical with that reported for porphyria cutanea tarda. Elevated porphyrin levels were significantly associated with HIV infection (P < .001) and were observed in patients with an elevated level of alanine aminotransferase (P = .03). Infection with hepatitis C virus was also associated with an elevation in porphyrin levels, although the increase was not statistically significant (P = .16). Porphyrin levels in patients positive for HIV were not correlated with serum urea nitrogen or creatinine levels. None of the patients had symptomatic porphyria cutanea tarda. CONCLUSIONS: Factors associated with increased serum porphyrin levels included HIV infection, elevated alanine aminotransferase levels, and, to a lesser extent, hepatitis C virus infection. These findings suggest that patients with the above risk factors are potentially predisposed to the development of symptomatic porphyria cutanea tarda on further exposure to hepatotoxic agents.

Acquired Immunodeficiency Syndrome↗