Biomedical subjects

Jung A Kim

Publications and source records attributed to Jung A Kim.

10 recordsLinked to original sources

PubMed2025

Impact of Muscle Quality on Muscle Strength and Physical Performance Beyond Muscle Mass or Diabetes Status.

BACKGROUND: Muscle quality, represented by myosteatosis, is recognized as an important factor in sarcopenia. In this study, we aimed to determine the associations between myosteatosis, muscle strength and physical performance among the elderly South Korean population. METHODS: We included 1440 participants (mean age 62.7 ± 6.2 years) from the Korean Genome and Epidemiology Study (KoGES). Based on the computed tomography attenuation of mid-thigh imaging, the total muscle area (TMA), normal-attenuation muscle area (NAMA), low-attenuation muscle area (LAMA) and inter-intramuscular adipose tissue (IMAT) and its indices were used to evaluate myosteatosis. Muscle strength was evaluated using hand grip strength, whereas physical performance was evaluated through 4-m gait speed, a 30-s sit-to-stand test and 2-min walking test. RESULTS: Of the 1440 patients, 51.5% were women, and 37.2% had diabetes. With aging, the LAMA index gradually increased, and the NAMA index gradually decreased in both men and women (p for trend < 0.001). The NAMA index was positively associated, whereas the LAMA and IMAT indices were negatively associated with muscle strength and physical performance after adjusting for age and sex. Higher tertiles of the NAMA index were consistently associated with improved physical performance across all appendicular skeletal muscle tertiles. The relationship between the NAMA index or LAMA index and muscle strength and physical performance did not differ according to diabetic status. Regular exercise was associated with a higher NAMA index and a lower LAMA index in the non-diabetic group; however, no significant difference in muscle quality was observed in the diabetic group in relation to exercise. CONCLUSIONS: Reduced myosteatosis was positively associated with greater muscle strength and better physical performance in both men and women, regardless of muscle mass or diabetes status; improving myosteatosis may be a therapeutic target for the prevention of sarcopenia.

Humans↗

PubMed2006

Evidence of post-transcriptional regulation in the maintenance of a partial muscle phenotype by electrogenic cells of S. macrurus.

Electrocytes, the current-producing cells of electric organs (EOs) in electric fish, are unique in that they derive from striated muscle and they possess biochemical characteristics of both muscle and non-muscle cells. In the freshwater teleost Sternopygus macrurus, electrocytes are multinucleated cells that do not contract yet retain expression of some proteins common to skeletal muscle cells. Given the role that transcriptional regulation plays in the activation of the myogenic program in vertebrates, we examined the expression patterns of several genes associated with multiple functions of skeletal muscle in mature electrocytes of S. macrurus. Our expression analyses detected transcripts for alpha-actin, alpha-acetylcholine (ACh) receptor (alpha-AChR), desmin, muscle creatine kinase (MCK), myosin heavy chain (MHC) isoforms, titin, tropomyosin, and troponin-T genes in the EO. However, immunolabeling studies revealed that electrocytes do not contain MCK, MHCs, or tropomyosin or troponin-T proteins. These results underscore the contribution of gene regulatory mechanisms in the maintenance of the muscle-like phenotype of EO that may be transcriptional-independent. We also report the classification and frequency of distinct transcripts from a random selection of 420 clones from an EO cDNA library. This is the first characterization of expressed genes in an EO, and it is an important step toward identifying mechanisms that affect different muscle protein systems for the evolution of highly specialized noncontractile tissues. Evidence of post-transcriptional regulation in the maintenance of a partial muscle phenotype by electrogenic cells of S. macrurus.

Animals↗

PubMed2006

The reasonable legal nursing manpower-staffing by using the system dynamics approach.

The Purpose of the study is to lay foundation for reasonable legal nursing manpower staffing by building the nursing manpower-staffing model. The System dynamics approach was adapted to build a simulation model. The model was built up on Vensim 5.0b DSS. In terms of economic efficiency on tertiary hospitals, the ratio of bed to nurse for the best reasonable legal nursing manpower-staffing is 3.0: 1(2.6:1 if calculating in terms of the ratio of patient to nurse) In terms of economic efficiency on secondary hospitals, the ratio of bed to nurse for the best reasonable legal nursing manpower-staffing is 3.5: 1(3.0:1 if calculating in terms of the ratio of patient to nurse).

Efficiency, Organizational↗

PubMed2006

Computer-tailored intervention program to promote breast-feeding.

The purpose of this study was to develop a computer-tailored intervention program to promote breast feeding. The education needs were measured with 100 pregnant or postpartum women. The types and scope of program contents were determined on the basis of the literature review and advice from experts. The materials to be included were collected and produced and a computer-tailored intervention program was produced through integration and computer programming of pathways. Then, an expert conducted the formative test and the program was modified by reflecting the results.

Breast Feeding↗

PubMed2005

Menopausal hormone therapy after breast cancer: a meta-analysis and critical appraisal of the evidence.

INTRODUCTION: Menopausal hormone therapy (HT) is typically withheld from breast cancer survivors because of concerns about risk for recurrence. Our objectives were to estimate the effects of HT on recurrence in breast cancer survivors and to examine the reliability of these estimates. METHODS: In a systematic review of the literature we identified all reports of HT use in breast cancer survivors that included comparison groups. Study design features that might affect selection of participants, detection of recurrence, and manuscript publication were assessed. The relative risks for breast cancer recurrence associated with HT were combined with random effects models. RESULTS: Two randomized and eight observational studies included 1,316 breast cancer survivors who used HT and 2,839 nonusers. In the observational studies, HT users were younger and more commonly node negative; only two reported balanced restaging for HT and control groups. Randomized trials suggest that HT increased the risk for recurrence (relative risk 3.41, 95% confidence interval 1.59-7.33), whereas observational studies suggest that HT decreased this risk (relative risk 0.64, 95% confidence interval 0.50-0.82). CONCLUSION: Results from observational studies of HT conducted in breast cancer survivors are discrepant with results from randomized trials. Observational studies of HT use in breast cancer survivors have design limitations that cannot be controlled for using standard statistical methods. Therefore, the randomized clinical trial data provide the only reliable estimates of the effect of HT use on recurrence risks in breast cancer survivors.

Age Factors↗

PubMed2005

Two species of goby, Boleophthalmus pectinirostris and Scartelaos sp., as the new second intermediate hosts of heterophyid fluke in Korea.

A survey was performed in order to determine the infection status of the metacercariae of heterophyid fluke in two goby species, Boleophthalmus pectinirostris and Scartelaos sp., collected from Gangjin-gun, and Shinangun, Sooncheon-shi, Jeollanam-do, Republic of Korea. A total of three metacercariae of Heterophyopsis continua was found in only one B. pectinirostris (10.0%) from Gangjin-gun. Heterophyes nocens metacercariae were detected in 24 B. pectinirostris (96.0%) and 14 Scartelaos sp. (63.6%) from Shinan-gun. Heterophyopsis continua metacercariae were found in 11 B. pectinirostris (44.0%) and 21 Scartelaos sp. (95.5%) from Shinan-gun. Stictodora fuscata metacercariae were detected in 18 B. pectinirostris (72.0%) from Shinan-gun. No metacercariae were detected in 20 B. pectinirostris from Sooncheon-shi. From the above results, this study is the first to prove that B. pectinirostris and Scartelaos sp. serve as the second intermediate hosts of some heterophyid flukes in Korea.

Animals↗

PubMed2004

Transcription of MyoD and myogenin in the non-contractile electrogenic cells of the weakly electric fish, Sternopygus macrurus.

The MyoD family of basic helix-loop-helix (bHLH) myogenic regulatory factors (MRFs) are transcriptional activators of skeletal muscle gene expression and are pivotal in inducing the full myogenic program. The expression of these factors after muscle differentiation is complete and the mechanism by which they modulate (or maintain) the muscle phenotype is less well understood. The myogenically derived electric organ (EO) of the electric fish Sternopygus macrurus is an excellent model to address this question. The electrocytes, i.e., the electrogenic cells of the EO, are not contractile but they do retain some muscle proteins. In order to examine the molecular regulatory pathways that control the muscle-to-electrocyte cell conversion, we have cloned the MyoD and myogenin cDNAs from S. macrurus. Clustal-based alignments showed that the functional domains observed in mammalian MyoD and myogenin are highly conserved in these MRF homologs. Expression analyses revealed that mature electrocytes, which retain the muscle proteins dystrophin, desmin, acetylcholine receptors (AChRs), alpha-actin, and alpha-actinin, also transcribe the MyoD and myogenin genes. RT-PCR studies confirmed that expression of these MRFs is confined to the myogenic lineage. Surprisingly, the levels of MyoD and myogenin transcripts in skeletal muscle and EO could not be used to predict the level to which a cell manifests the muscle program. We conclude that expression of multiple MRFs is not sufficient to induce non-contractile cells to fully express the skeletal muscle program. These data also suggest that the MRF transcriptional program in S. macrurus may be distinct from MRF-dependent myogenesis in other vertebrate systems.

Amino Acid Sequence↗

PubMed2003

Estrogen deficiency symptom management in breast cancer survivors in the changing context of menopausal hormone therapy.

Vasomotor symptoms associated with menopause or cancer therapies represent an increasingly common problem for breast cancer survivors given the increasing use of ovarian suppression in premenopausal women and aromatase inhibitors in postmenopausal women. Although estrogen and/or progestin effectively reduce vasomotor symptoms, a recent Women's Health Initiative (WHI) randomized trial identified an unfavorable risk/benefit balance on life-threatening diseases, including increased breast cancer, for combined estrogen plus progestin use in otherwise healthy postmenopausal women. As a result, use of menopausal hormone therapy (MHT) for chronic disease risk reduction in any population cannot be supported. In addition, the safety of estrogen and/or progestin regarding risk of recurrence or new cancer development in breast cancer survivors has not been demonstrated. For vasomotor symptoms in this population, neuroendocrine agents, including selective seratonin reuptake inhibitors (SSRIs) or gabapentin, are reasonable choices with substantial impact on hot flashes and moderate toxicity profiles. When rigorously evaluated, most other nonhormonal pharmacologic and herbal interventions have been found to have either modest or no efficacy and/or limiting toxicity. In breast cancer survivors even local vulvar/vaginal symptoms are best treated by nonhormone products since drug absorption with systemic estrogen-like effects has been reported. Estrogen/progestin use in breast cancer survivors should be considered only for women with severe vasomotor symptoms refractory to other approaches after extensive informed decision-making including review of current Food and Drug Administration labeling concerns with use limited to the lowest dose and shortest duration possible.

Breast Neoplasms↗

PubMed2002

Transforming growth factor-beta1 as a useful serologic marker of small hepatocellular carcinoma.

BACKGROUND: Although alpha-fetoprotein (AFP) is a useful serologic marker of hepatocellular carcinoma (HCC), it has been reported insufficiently sensitive in detecting small HCCs. Plasma transforming growth factor-beta1 (TGFbeta1) has been reported to be elevated in HCC patients compared with liver cirrhosis patients. It has been reported that TGFbeta1 mRNA was overexpressed in HCC, especially in patients with small HCC and well-differentiated HCC compared with patients with liver cirrhosis. The current study investigated the usefulness of TGFbeta1 compared with AFP in the diagnosis of small HCCs. METHODS: Thirty-eight patients with small HCC (< or = 3 cm), 31 patients with liver cirrhosis only, and 23 normal volunteers were studied. Using plasma TGFbeta1 and serum AFP levels measured at the time of diagnosis, the sensitivities and specificities were calculated in the diagnosis of small HCCs. RESULTS: Plasma TGFbeta1 and serum AFP levels were significantly higher in patients with small HCC than in those with liver cirrhosis. In diagnosing small HCCs, the cut-off values of plasma TGFbeta1 and serum AFP were 800 pg/mL and 200 ng/mL, respectively, where the specificities were over 95%. At the cut-off level of plasma TGFbeta1 and serum AFP, the sensitivities were 68% and 24%, respectively. CONCLUSIONS: The current results suggest that TGFbeta1 may be a useful serologic marker in detecting HCCs earlier because it shows higher sensitivity than, with specificity as, AFP in the diagnosis of small HCCs.

Adult↗

PubMed2002

Fiber size, type, and myosin heavy chain content in rhesus hindlimb muscles after 2 weeks at 2 G.

BACKGROUND: Fiber atrophy and an increase in the percentage of fast fibers have been observed in Rhesus leg muscles after spaceflight. HYPOTHESIS: Hypergravity will result in muscle fiber hypertrophy and an increase in the percentage of slow fibers. METHODS: Open muscle biopsies were obtained from Rhesus soleus, medial gastrocnemius (MG), and tibialis anterior (TA) muscles before and after 14 d of centrifugation (2 G) and in time-matched controls. Cage activity levels were measured by telemetry. RESULTS: Based on monoclonal antibody binding for myosin heavy chains (MHC), the fastest region of soleus contained a higher proportion of type I+II (27 vs. 13%) and had a tendency for a lower proportion of type I (38 vs. 61%, p = 0.10) fibers after than before centrifugation. There was a higher proportion of type I+II fibers in post- vs. pre-2 G (10 vs. 0.6%) MG biopsies. Fiber type distribution and MHC composition were unaffected in the TA. Overall, mean fiber sizes were unaffected by centrifugation. Average cage activity levels were 36% lower during than before 2 G. CONCLUSIONS: Our hypothesis was rejected. The changes in the proportion of fibers expressing type I MHC are the reverse of that expected with chronic loading of extensors and, paradoxically, are similar to changes observed with chronic unloading, such as occurs during spaceflight, in this primate model. The data are consistent with the observed decrease in total daily activity levels.

Adaptation, Physiological↗