Biomedical subjects

I Wong

Publications and source records attributed to I Wong.

42 records · Page 3Linked to original sources

PubMed1982

Bee sting of the cornea: case report.

Three cases of corneal bee sting were treated. Each eye reacted differently from the others: case 1 with severe pain, conjunctival chemosis and hyperemia, central corneal edema, and reduced visual acuity; case 2 with severe pain, conjunctival hyperemia, and a white corneal infiltrate; and case 3 with only a minimal foreign-body sensation. The reaction to the venom can be toxic or immunologic. The behavior of the toxins-melittin, apamin, and formic acid-and of the principal allergen (probably phospholipase A) are described.

Adult↗

PubMed1981

Serum and tear antibodies to Chlamydia after reinfection with guinea pig inclusion conjunctivitis agent.

Repeated inoculation of th eyes of guinea pigs with the naturally occurring Chlamydia psittaci agent, guinea pig inclusion conjunctivitis (GPIC), showed that animals gradually become susceptible to reinfection with the passage of time after primary infection. Higher levels of serum IgG antibody had a significant association with resistance to challenge inoculation only with a high dose (250 ELD50) but not with a low dose (25 ELD50) inoculum. With each inoculum, however, some animals with high serum antibody were susceptible. the presence of antibodies in tears did not correlate with resistance to the first low-dose challenge inoculation, but both tear IgG and secretory antibody did have a significant association with resistance on the second rechallenge with a high-dose inoculum. Topical treatment of the eye with immune serum or tears during primary infection reduced the amount of agent in the conjunctiva only during the period of application. Local treatment of the eye with heat-killed vaccine prior to primary infection did not produce detectable antibody or protect animals against challenge inoculation; this local immunization did "prime" the animals, however, so that they had an accelerated antibody response after infection. Although there is abundant evidence that local immunity has an important role in resistance to challenge inoculation with GPIC, serum and tear antibody levels correlate equally well with resistance to repeated ocular challenge inoculation. Effective immunization procedures for this chlamydial infection then would involve stimulation of both local and systemic immune responses.

Animals↗

PubMed1975

Dominantly inherited osteogenesis imperfecta in man: an examination of collagen biosynthesis.

We have examined control subjects and patients in an effor to discover a metabolic basis for dominantly inherited osterogenesis imperfecta (OI). Studies were carried out in vitro with cultured skin fibroblasts obtained from OI patients, and in vivo on peptide-bound hydroxyproline excretion in urine. Urinary hydroxyproline excretion (milligrams/24 hr) adjusted for age is essentially normal in OI patients, although the mean excretion rate is below average. The latter finding is presumably a reflection of the smaller body mass of OI patients. The OI skin fibroblasts, matched for age of donor, site of biopsy, phase of growth, and generation number in culture, incorporated L-proline into hot trichloroacetic acid (TCA)-soluble protein (collagen) at normal rates. The rate of conversion of proline to hydroxyproline in the nascent polypeptides is also normal in OI. Incorporation of L-lysine was also normal in OI. These findings indicate that peptide synthesis of collagen is not impaired in OI. Rates of galactose incorporation into collagen and the extractability of collagen into normal saline or 0.2 M citric acid were all normal both in OI cells and in the culture medium recovered from the monolayer. These findings, in combination with the urinary data on hydroxyproline excretion in vivo reveal that cross-linking and export of collagen in OI is essentially normal. The elution profile after ion exchange chromatography of fibroblast collagen on carboxymethyl (CM)--Sephadex was also examined. The normal 2/1 ratio of peak 1 (largely alpha 1(1) chains) to peak 2 ) largely alpha 2 chains) was found in OI fibroblast extracts, which implies that synthesis and initial aggregation of the two types of polypeptide to yield (alpha1(1))-2 alpha 2 collagen composition is not abnormal in OI. Despite the negative biochemical findings, a consistent defect in the morphology of OI cells was identified in the log phase and the confluent phase of monolayer cultures. The finding is characterized by irregular packing of the aggregated cells and by an irregular tessellated appearance of the individual OI fibroblast. This observation reassures us that the inherited defect is expressed in vitro.

Adolescent↗

PubMedDate not supplied

Infection by human cytomegalovirus and rubella virus of cultured human fetal islets of Langerhans.

Several viruses are implicated in the pathogenesis of pancreatic beta cell destruction and the onset of insulin-dependent (type 1) diabetes mellitus (IDDM). However, it is still controversial as to whether viral infection can exert direct cytopathic effects on beta cells. We have studied the effect of infection by human cytomegalovirus (CMV) and rubella virus on human fetal pancreatic islets in tissue culture. Although morphological changes were observed in CMV-inoculated islet cells, such infection did not lead to changes in levels of secreted immunoreactive insulin. On the other hand, infection by rubella virus did lead to significantly lower levels of immunoreactive insulin in the absence of demonstrable cytopathic effect. These results indicate that viral infection of human pancreatic islet tissue can occur as demonstrated through tissue culture techniques, and that such infection leads to changes in levels of secreted insulin in some cases but not others.

Cell Transformation, Viral↗

PubMedDate not supplied

Maturation of human fetal and infantile thymic cells in tissue culture.

Human fetal and infantile thymic epithelial (TE) cells were grown in tissue culture and were phenotypically characterized using monoclonal antibodies reactive against a number of individual components of human thymus. Cultures of infantile TE cells formed confluent monolayers after 14-17 days. This was accompanied by a dramatic increase in numbers of Hassall's corpuscles, septae formation and pseudolobulation. After 3 weeks in culture, the rate of cell growth slowed, and by 4 weeks an accumulation of fat cells was noted. Involution of the cultures occurred after this time. In contrast, cultures of fetal TE cells achieved confluence after only 6-8 days, and increased numbers of Hassall's corpuscles, septae formation and pseudo-lobulation could be observed after only 10 days. Fat cells appeared after 3 weeks in culture and involution occurred soon after. Cells which reacted with monoclonal antibodies specific for keratin and GQ ganglioside were predominant during the early stages of tissue culture. These cells ceased to play as important a role with increased time in culture; in contrast, cells reactive with monoclonal antibodies specific for distinct thymic components increased in number as time in culture progressed.

Aging↗

PubMedDate not supplied

Effect of cytomegalovirus on lectin-driven mitogenesis of human thymic and peripheral blood lymphocytes.

Human cytomegalovirus (CMV), when added to cultures of either thymic or peripheral blood lymphocytes, was able to prevent these cells from responding to mitogenic stimulus. This effect was only obtained when live virus was utilized, and is apparently dependent on the ability of such virus to establish abortive infections in the cell cultures. CMV-infected cultures became deficient in terms of ability both to produce interleukin-2 (IL-2) activity as well as to respond to purified, recombinant IL-2 which was added exogenously. Similar results were obtained using either a laboratory strain (AD-169) of CMV or freshly-obtained clinical isolates of this virus which had been grown in tissue culture.

Adult↗