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Biomedical subjects

H Kim

Publications and source records attributed to H Kim.

1,177 records · Page 66Linked to original sources
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When the rehabilitation ideal fails: a study of parental rights termination.

This study explored the circumstances of parents whose extreme neglect and abuse of their young children justified the drastic state action of termination of their parental rights. Records of 97 children age 6 and under whose parental rights were terminated between 1991 and 1997 in Minnesota were reviewed. Profiles of parents and children were drawn from these data, and a "risk pool" of parents whose children became wards of the state was identified. Guidelines are drawn from this "risk pool" that may help alert practitioners to those parents who are unlikely to safely maintain their children. Questions and implications for policy and practice are highlighted.

Adolescent↗
PubMedDate not supplied

pH and oxidation-reduction potential control strategy for optimization of nitrogen removal in an alternating aerobic-anoxic system.

An alternating aerobic and anoxic (AAA) system is a continuous-flow, activated-sludge process in which the environmental conditions necessary to meet the specific requirements for aerobic nitrification and anoxic denitrification are created. Because of stricter regulations on wastewater effluent and concerns on energy consumption, the process control of the system is now becoming more important. A bench-scale AAA system with different fixed aeration ratios was operated for more than 8 months to evaluate effects of the total cycle time and aeration ratio on the system performance and to develop a feasible control scheme. With supplemental organic addition, the system shows removal efficiencies of 85 to 90% and 78 to 82% for chemical oxygen demand and total nitrogen, respectively. The oxidation-reduction potential (ORP) and pH profiles indicate that the aerobic cycle can be controlled by a control point (ammonia valley) on the pH profile indicating the end of nitrification and the anoxic cycle controlled by another point (nitrate knee) on the ORP profile signifying the end of denitrification. Thus, a dual control strategy with the pH and ORP control points was used for terminating aerobic-anoxic and initiating anoxic-aerobic cycles in an AAA system. The performance of the online control system is excellent, with a significant energy saving (average aeration ratio, fa = 0.23) as compared to the fixed time systems (fa = 0.33 to approximately 0.5).

Ammonia↗
PubMedDate not supplied

Asiatic acid derivatives protect cultured cortical neurons from glutamate-induced excitotoxicity.

Asiatic acid, a triterpene of Centella asiatica (L.) Urban (Umbelliferae), has been patented as a treatment for dementia and an enhancer of cognition by the Hoechst Aktiengesellschaft (EP 0 383 171 A2). We modified the chemical structure of asiatic acid and obtained 36 derivatives of asiatic acid in an attempt to prepare neuroprotective compounds that were more efficacious than asiatic acid itself. The neuroprotective activities of these derivatives were evaluated using primary cultures of rat cortical neurons insulted with the neurotoxin, glutamate, as an in vitro screening system. Among the semi-synthesized derivatives, three derivatives significantly mitigated the neurotoxicity induced by glutamate in this screening system. The neuroprotective activities of these 3 derivatives appeared to be more powerful than that of asiatic acid itself. These 3 derivatives significantly attenuated decreases in the levels of glutathione, glutathione peroxidase and other enzymes, which participate in the cellular defense mechanisms blunting oxidative stress. Furthermore, they significantly reduced the overproduction of NO induced by glutamate. These results showed that these derivatives of asiatic acid exerted significant neuroprotective effects on cultured cortical cells by their potentiation of the cellular oxidative defense mechanism. Therefore, these agents may prove to be efficacious in protecting neurons from the oxidative damage caused by exposure to excess glutamate.

Animals↗
PubMedDate not supplied

Lack of suppression of tumor cell phenotype by overexpression of TIMP-3 in mouse JB6 tumor cells identification of a transfectant with increased tumorigenicity and invasiveness.

BACKGROUND: We have recently cloned mouse tissue inhibitor of metalloproteinases-3 (mTIMP-3) by the differential display technique and found that mTIMP-3 was expressed in preneoplastic but not in neoplastic mouse JB6 epidermal cells (Sun et at. Cancer Res. 54:11139, 1994). This down regulation of the gene is attributable at least in part to alteration in gene methylation (Sun et al., J. Biol. Chem., 270:19312, 1995). METHODS: To examine the potential role of TIMP-3 in two JB6 tumor cell model, we overexpressed mouse TIMP-3 in two JB6 tumor cell lines lacking endogenous mTIMP-3 expression. Stable transfectants from each line were selected and assayed for possible changes in tumor cell phenotype. RESULTS: Our results showed overexpression of mTIMP-3 in these two tumor lines did not change their ability to grow in soft agar, an assay for anchorage-independent growth, nor in nude mice, an in vivo tumorigenicity assay, nor to penetrate matrigel, an assay for invasiveness We, however, isolated a clone which is highly malignant was demonstrated by a) very short latent period for tumor formation; b) very fast tumor growth; and c) highly invasive in the matrigel assay. CONCLUSION: We conclude from this study that although TIMP-3 is not expressed in mouse JB6 tumor cells, overexpression by DNA transfection did not reverse tumor cell phenotype, suggesting a complex role for TIMP-3 in tumorigenesis. The highly malignant transfectant isolated by this study can be used as a tool for the cloning of dominant oncogenes as well as tumor suppressor genes.

Animals↗
PubMedDate not supplied

Reciprocal inhibition in the forearm during voluntary contraction and thinking about movement.

The regulatory mechanism for the interaction of agonist and antagonist muscles is not still clear. In these studies we investigated reciprocal inhibition during voluntary contraction and thinking about movement by using transcranial magnetic stimulation (TMS) and the H reflex technique. Magnetic stimuli, with intensities 10% above threshold, were delivered at the scalp under 3 experimental conditions; at rest, during voluntary isometric weak contraction and during thinking about movement. Surface EMG responses were taken from extensor carpi radialis (ECR) and flexor carpi radialis (FCR) muscles in 14 normal subjects. Inhibitions of antagonist muscles induced by thinking about agonist movement occurred in 8 ECR and 10 FCR muscles, but most of them were not statistically significant. H reflexes were obtained from the FCR muscles in 10 normal subjects under the same conditions. Voluntary wrist extension and thinking about wrist extension produced inhibition of the H reflex in the FCR muscles. Reciprocal inhibition of antagonist muscles may occur at the cortical and spinal cord levels. The excitability of motoneurons has effects on the H reflex amplitude. Motor evoked potential (MEP) response to TMS might be affected by the combination of input from the motor cortex and the spinal cord. TMS may evoke simultaneous facilitatory and inhibitory volleys to antagonist muscles. This may explain why the inhibitions in the TMS study were weaker than those in the H reflex study.

Adult↗