PubMed Health⌕ Search

Biomedical subjects

G Chun

Publications and source records attributed to G Chun.

9 recordsLinked to original sources
PubMed2002

Comparative analysis of the complete genome sequences of Helicoverpa zea and Helicoverpa armigera single-nucleocapsid nucleopolyhedroviruses.

The complete nucleotide sequence of Helicoverpa zea single-nucleocapsid nucleopolyhedrovirus (HzSNPV) has been determined (130869 bp) and compared to the nucleotide sequence of Helicoverpa armigera (Ha) SNPV. These two genomes are very similar in their nucleotide (97% identity) and amino acid (99% identity) sequences. The coding regions are much more conserved than the non-coding regions. In HzSNPV/HaSNPV, the 63 open reading frames (ORFs) present in all baculoviruses sequenced so far are much more conserved than other ORFs. HzSNPV has four additional small ORFs compared with HaSNPV, one of these (Hz42) being in a correct transcriptional context. The major differences between HzSNPV and HaSNPV are found in the sequence and organization of the homologous regions (hrs) and the baculovirus repeat ORFs (bro genes). The sequence identity between the HzSNPV and HaSNPV hrs ranges from 90% (hr1) to almost 100% (hr5) and the hrs differ in the presence/absence of one or more type A and/or B repeats. The three HzSNPV bro genes differ significantly from those in HaSNPV and may have been acquired independently in the ancestral past. The sequence data suggest strongly that HzSNPV and HaSNPV are variants of the same virus species, a conclusion that is supported by the physical and biological data.

Animals↗
PubMed1995

Self-reported signs and symptoms in breast implant patients with novel antibodies to silicone surface associated antigens [anti-SSAA(x)].

In research animals, the immune adjuvant activity of silicone in eliciting antibodies to associated protein antigens is now well established. In humans, the immune adjuvant activity of silicone remains controversial. Clusters of data from various research groups are beginning to define the boundary conditions for future large epidemiological studies. In that spirit, this manuscript reports pilot clinical data from a serological study conducted 3 years ago and reported previously in this journal. Sera from a self-selected symptomatic population of patients with breast implants were assayed for elevated concentrations of antibodies showing binding avidity to silicone surface associated antigens [anti-SSAA(x)]. In that study of 249 patients, two distinct statistically significant subgroups were identified on the basis of the serological assay alone: patients without any elevated anti-SSAA(x) (negative) and patients with elevated anti-SSAA(x) (positive) (p < 0.001). In this study, a clinical survey returned by 226 of those patients was correlated with the previously acquired serological findings. The 11 most common clinical complaints reported by the 199 anti-SSAA(x) negative patients and by the 27 anti-SSAA(x) positive were compared and their frequencies analyzed. The 199 anti-SSAA(x) negative patients, as a group, showed a lower frequency of a variety of signs and symptoms compared to the 27 anti-SSAA(x) positive patients. Statistically significant differences were seen in three of the symptoms: fever, foot pain, and sleep disturbance (p < 0.05). In addition, the syndrome of fever in the absence of local chest pain was a significantly associated with anti-SSAA(x) positivity (p < 0.001).

Antibodies↗
PubMed1993

High-purity resident tissue macrophage isolates from human synovium and periprosthetic tissues using immunomagnetic techniques.

Destruction of periarticular and periprosthetic bone by activated macrophages, a process often termed "macrophage mediated osteolysis," is recognized as a leading mechanism of aseptic arthroplasty failure. To develop effective interventional approaches and increase the longevity of implanted joint prostheses, the pathobiology of activated human-synovium-derived macrophages needs to be better characterized. The first step toward achieving this research objective is the acquisition of pure populations of macrophages from human synovial tissue. A simple, fast, and highly efficient method for isolating a relatively pure population of macrophages from periprosthetic tissue received from either primary or secondary arthroplasty is presented. This technique uses murine monoclonal antibodies (IgG) that recognize a phagocyte-specific marker, CD68, for primary binding, and sheep anti-murine IgG antibodies bound to polystyrene-coated magnetic microspheres for secondary binding. While the primary antibody specifically labels CD68-positive phagocytes in the digestion of synovial and periprosthetic tissue, the secondary antibody bound to polystyrene-coated iron oxide beads facilitates the removal of CD68-positive cells from CD68-negative cells by anchoring the former with a magnet. This protocol requires centrifugation only in the washing steps, which reduces the frequency of cell death and altered cell morphology. The patient population includes three primary and eight revision arthroplasties. The tissue macrophage isolation protocol yielded on average 4 x 10(5) cells/g tissue, of which 91% were viable nonspecific esterase positive macrophages. The experimental results suggest that immunomagnetic beads coupled to anti-CD68 enable the isolation of a purified population of resident tissue macrophages suitable for further biologic characterization.

Adult↗
PubMed1990

Rapid-acting parenteral antihypertensive agents.

Parenteral antihypertensive agents are useful in those clinical situations where rapid reduction of blood pressure is necessary or where treatment with oral antihypertensive medications is not feasible. Given the diverse selection of parenteral antihypertensive drugs now available, therapy can be individualized. The presence of concurrent diseases will often influence the decision-making process regarding choice of an agent. Complications of parenteral antihypertensive therapy can arise from the intrinsic properties of the various drugs or the development of severe hypotension. Gradual lowering of blood pressure, in conjunction with careful clinical evaluation, will minimize the risks of acute parenteral antihypertensive therapy. Given that parenteral antihypertensive therapy often needs to be replaced by oral therapy, those drugs that can be used both parenterally and orally may have an advantage.

Antihypertensive Agents↗
PubMed1984

Computed tomographic findings in bowel infarction.

Findings on computed tomography (CT) were considered diagnostic or highly suggestive in seven cases of bowel infarction. Important findings were portal or mesenteric venous gas, intramural gas, focal thickening of bowel wall, focal or diffusely dilated fluid-filled bowel, and clot in the superior mesenteric artery. Only one patient had unequivocal extraluminal gas on initial abdominal radiographs, although others had equivocal findings or later developed obvious extraluminal gas. Because CT may detect extraluminal gas and mesenteric arterial occlusion not apparent on plain films, and because CT is increasingly used early in the evaluation of abdominal pain, it can play an important role in the diagnosis and management of bowel infarction.

Adult↗
PubMed1971

Marijuana: a realistic approach.

Much of the current confusion concerning marijuana has been caused by a lack of definition of terms. Variations in drug effect that are related to the type and potency of cannabis preparation and route of administration need clarification. When domestic strength marijuana is smoked recreationally, the subjective effects include relaxation, mild euphoria and increased sensory awareness. The objective effects include tachycardia, reddening of the conjunctivae and a distorted sense of time. Undesirable effects such as panic reactions, amotivational behavior, and acute toxic psychosis occur infrequently and are reversible with proper therapy. Other effects which have been attributed to marijuana are unsubstantiated. The recent upsurge in use of marijuana involves persons of a different type than those who used it heretofore and has greatly increased the number of people familiar with the drug. The disparity between what many people know empirically and the information disseminated through official media has lessened the credibility of physicians with many of our younger citizens. When young people recognize misinformation about marijuana, they are no longer listening when the facts are presented about more dangerous drugs, and the abuse of these drugs must be our main concern. To be considered is the potential hazard to adolescent users who may concomitantly be exposed to a subculture of experimentation with stronger drugs at a time when the opinion of a peer group is a strong factor in their behavior.

Brain↗