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Biomedical subjects

A J Kim

Publications and source records attributed to A J Kim.

8 recordsLinked to original sources
PubMed2005

Disc regeneration: why, when, and how.

There is increasing acknowledgment that patients with back pain who are candidates for surgery, will benefit over the long term from less invasive procedures that facilitate dynamic stabilization, rather than fusion. Dynamic stabilization can be addressed by providing assistance using mechanical devices, or relying on biologic processes such as tissue regeneration and repair. The concept of biologic disc repair has grown in recent years because of improved understanding of the cellular and molecular events of disc aging and degeneration. This article describes approaches to cell therapy, reviews relevant studies, and discusses ways to maximize clinical efficacy. Tissue engineering approaches for disc regeneration and healing have significant clinical potential.

Guided Tissue Regeneration↗
PubMed2000

Genetic characterization of rebounding HIV-1 after cessation of highly active antiretroviral therapy.

Despite prolonged treatment with highly active antiretroviral therapy (HAART), infectious HIV-1 continues to replicate and to reside latently in resting memory CD4(+) T lymphocytes, creating a major obstacle to HIV-1 eradication. It is therefore not surprising to observe a prompt viral rebound after discontinuation of HAART. The nature of the rebounding virus, however, remains undefined. We now report on the genetic characterization of rebounding viruses in eight patients in whom plasma viremia was undetectable throughout about 3 years of HAART. Taking advantage of the extensive length polymorphism in HIV-1 env, we found that in five patients who did not show HIV-1 replication during treatment, the rebound virus was identical to those isolated from the latent reservoir. In three other patients, two of whom had been free of plasma viremia but had showed some residual viral replication, the rebound virus was genetically different from the latent reservoir virus, corresponding instead to minor viral variants detected during the course of treatment in lymphoid tissues. We conclude that in cases with apparent complete HIV-1 suppression by HAART, viral rebound after cessation of therapy could have originated from the activation of virus from the latent reservoir. In patients with incomplete suppression by chemotherapy, however, the viral rebound is likely triggered by ongoing, low-level replication of HIV-1, perhaps occurring in lymphoid tissues.

Adult↗
PubMed2000

The effects of Pva/chitosan/fibroin (PCF)-blended spongy sheets on wound healing in rats.

The effects of poly vinyl alcohol (PVA)/Chitosan/Fibroin (PCF)-blended sponge on wound healing in rats were investigated. We excised the skin of a rat, including the dermis, approximately 2 x 2 cm in size. The wound was covered with PCF-blended spongy sheets. The spongy sheets absorbed the exudate, and gained flexibility and softness. Histopathological inspection of the wound 12 d later showed an increase of vascular ingrowth and the absence of inflammatory cells. Regeneration of the skin around the wound was faster than that of the control. We also tested wound healing effects of PVA, Chitosan and Fibroin, alone or in various combinations. Wound healing was accelerated in the order of PCF-blended sponge>Chitosan/Fibroin (CF)-blended sponge>Fibroin (F) sponge > PVA/Chitosan-blended sponge (PC) > Chitosan (C) sponge.

Animals↗
PubMed1998

The lacrimal keyhole, orbital door jamb, and basin of the inferior orbital fissure. Three areas of deep bone in the lateral orbit.

OBJECTIVES: To calculate the volume of bone in 3 areas of the deep lateral orbit that are available for removal in decompression surgery and to demonstrate these 3 areas within a 3-dimensional computed tomographic reconstruction of the orbit. DESIGN: The 3 areas of bone in the deep lateral orbit were designated the lacrimal keyhole, the sphenoid door jamb, and the basin of the inferior orbital fissure. By means of digitized computed tomographic scans, these 3 areas of bone were analyzed by measuring preoperative and postoperative orbital volumes and predicted bony expansion volumes in 9 patients (17 orbits) who underwent deep lateral orbital decompression surgery. We also calculated the volume of bone that could be removed from 11 normal orbits. A 3-dimensional computer reconstruction of an orbital computed tomographic scan was created, and the 3 areas of potential bone were delineated within it. RESULTS: The average volumes of the basin of the inferior orbital fissure, the sphenoid door jamb, the lacrimal keyhole, and the total of the 3 regions were 1.2, 2.9, 1.5, and 5.6 cm3, respectively. The 3 areas of bone contributed variably to the total, with the door jamb contributing the most volume of the 3, nearly twice the value of the other 2. There was, however, a significant amount of interpatient variability, especially for the door jamb region. CONCLUSION: Orbital decompression surgery of the deep lateral wall can provide adequate volume expansion because of the amount and location of potential space that exists in the 3 areas of deep bone.

Adult↗
PubMed1997

Asymmetrical regulation of blood pressure in the rat medulla.

The effects of microinjection of serotonin-1 (5-HT1) antagonist methiothepin and 5-HT1 agonist buspirone into the nucleus reticularis parvocellularis were investigated in the anaesthetized rats. Methiothepin produced an increase in arterial blood pressure when injected into the left side, but it did a decrease when injected into the right side. On the contrary, buspirone produced a decrease in arterial blood pressure when injected into the left side, but it did an increase when injected into the right side. These findings provide the clue to clarify that there is a reciprocal regulation of arterial blood pressure between the left and right sides in the rat medulla.

Animals↗
PubMed1997

Purification and characterization of the prothoracicotropic hormone of Drosophila melanogaster.

The prothoracicotropic hormone (PTTH) of Drosophila melanogaster is a modulator of ecdysteroid (molting hormone) synthesis and was isolated and characterized from extracts of whole larvae (approximately 4 x 10(5) larvae). The purification protocol included delipidation, salt-extraction, heat treatment, conventional column chromatography, and HPLC, and yielded about 50 microg of pure hormone. Biological activity was followed using a ring gland in vitro assay in which ecdysteroidogenesis by control ring glands as measured by radioimmunoassay was compared with ring gland incubations containing active fractions. The molecular weight of the purified PTTH was 45 kDa and N-terminal amino acid sequence analysis indicated that those analyzed sequences displayed no significant homology with known peptides or peptide hormones, including PTTH from the silkmoth, Bombyx mori. Western blot analysis indicated that the native form of Drosophila PTTH was a single 66-kDa polypeptide with N-linked carbohydrate chains and intrachain disulfide bonds. The purified 45-kDa peptide is the deglycosylated form, a result of glycosidase activity present during preparation of the PTTH extract. The deglycosylated form shows heterogeneity, presumably as a result of varying degrees of deglycosylation at the N terminus.

Animals↗