Comparison of dot immunobinding assay, enzyme-linked immunosorbent assay and immunodiffusion for serodiagnosis of paratuberculosis

A rapid, simple and inexpensive dot immunobinding assay (DIA) was evaluated for the serodiagnosis of paratuberculosis in cattle. The assay was performed on nitrocellulose strips which were dotted with purified protoplasmic antigen of Mycobacterium paratuberculosis. After incubation with test serum samples, the bound antibodies were detected using an enzyme-amplified immunostaining procedure. The efficacy of DIA as a screening test for paratuberculosis was compared to that of an enzyme-linked immunosorbent assay (ELISA), a modified agar gel immunodiffusion (mAGID) test, and an AGID test using 329 serum samples from cattle which were examined for M. paratuberculosis infection by a sensitive fecal culture technique. The DIA and ELISA had comparable results and both of the enzyme immunoassays had higher sensitivity than tests based on AGID. The sensitivity of all four tests was influenced by the intensity of fecal bacterial shedding. Preabsorption of sera with Mycobacterium phlei increased the sensitivity of both enzyme immunoassays. the specificity but reduced the sensitivity of both enzyme immunoassays.

[Comparison of the bactericidal effects of acid glutaraldehyde and alkaline glutaraldehyde]

Two glutaraldehydes, acid glutaraldehyde (sonacide) and alkaline glutaraldehyde (cidex) were evaluated for their bactericidal effect under different conditions. Two percent acid and alkaline glutaraldehyde could destroy vegetative bacteria and spores in twenty minutes. Less than 2.9 percent residual contamination rate could be achieved after immersing equipment in 0.1 percent acid glutaraldehyde or 0.5 percent alkaline glutaraldehyde for 30 minutes. Complete sterilization could be obtained by using two percent acid glutaraldehyde, while 0.5 percent residual contamination was noted after equipment had been immersed in two percent alkaline glutaraldehyde for one month. Acid glutaraldehyde could destroy bacteria completely in 30 minutes even after the solution had been standing for one month, but alkaline glutaraldehyde had an 11.4 to 26.9 percent residual rate. There were no deleterious effects on metal equipment after immersing for 14 days, but yellowish discoloration and hardening were observed on plastic and rubber equipment. It is concluded that both of these two glutaraldehydes are effective bactericides, but acid glutaraldehyde is more effective even after standing for one month or after dilution.

[Sarcoidosis with ocular involvement]

A 28-year-old Chinese woman having sarcoidosis with ocular involvement was reported. She demonstrated bilateral hilar lymphadenopathy in a chest X-ray which was taken for a cough. Transbronchial lung biopsy revealed noncaseating epithelioid granulomas. Blurred vision occurred 8 months later when conjunctival follicle-like masses, granulomatous keratic precipitates, iridocyclitis, "snow-ball" vitreous opacity, and retinal periphlebitis developed in both eyes. Biopsy of the conjunctival follicle-like masses revealed noncaseating granulomas composed of epithelioid cells and multinuclear giant cells, typical of sarcoidosis. The ocular lesions waned under topical steroid treatment and vision improved. This is the only case with an ocular involvement among the 10 cases of sarcoidosis seen during the past 20 years at the Taipei Veterans General Hospital.

HLA antigens among Chinese in Taiwan: association of Cw1 and Cw3 on the same haplotype

HLA-A, B and C phenotypes and gene frequencies of Chinese living in Taiwan are presented. Cw1 and Cw3 were frequently found to segregate together on the same haplotype.

The para-Bombay phenotype in Chinese persons

The para-Bombay phenotype occurs more frequently in Oriental than in white populations. This report describes the immunohematologic findings in 20 cases of the para-Bombay phenotype detected over a period of about 15 months in the Chinese population of Taiwan.

Lipid requirements for reconstitution of the proton-translocating complex of clathrin-coated vesicles

We have recently reported the reconstitution of the clathrin-coated vesicle proton-translocating complex with liposomes prepared from ethanol-extracted crude bovine brain lipids. Reconstitution of proton pumping by the isolated proton ATPase has now been achieved with liposomes prepared from pure lipids. Optimal proton pumping, as assessed by ATP-generated acridine orange quenching and 32Pi-ATP exchange, is achieved with liposomes prepared from phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and cholesterol at a weight ratio of 40:26.5:7.5:26, and a lipid-to-protein weight ratio of 200:1. Under such conditions, the extent of decrease of ATP-generated acridine orange quenching is 150-fold greater than that of native clathrin-coated vesicles. Cholesterol is required to stabilize the proteoliposome. Phosphatidylserine, which is most effective in activating ATP-hydrolytic activity of the solubilized enzyme, is not obligatory for reconstitution of proton pumping.

Stimulation of prostaglandin formation by vasoactive mediators in cultured human endothelial cells

Human endothelial cells in culture synthesize prostaglandins and release these products into the culture medium. The major products of arachidonic acid metabolism were identified by high pressure liquid chromatography or thin layer chromatography, and release of prostaglandins was measured by radioimmunoassays. Addition of histamine or bradykinin enhanced release of prostaglandins in both arterial and venous endothelial cells. Other vasoactive compounds including angiotensin II, vasopressin, substance P, epinephrine, norepinephrine, or isoproterenol were ineffective. Release of prostaglandins by histamine was concentration-related, and involved H1 receptors, as determined by addition of histamine antagonists. Incubation of endothelial cells with 14C-arachidonic acid resulted in a time-dependent uptake into cell lipids, where most of the radioactivity was incorporated into phosphatidyl choline and neutral lipids. Endothelial cells released 14C-arachidonic acid as well as 14C-prostaglandins in response to either histamine or bradykinin. The enhanced release of 14C-prostaglandins was inhibited by either indomethacin or mepacrine, but 14C-arachidonic acid release was inhibited only by mepacrine. We conclude that the vasoactive compounds, histamine and bradykinin, stimulate formation of prostaglandins in endothelial cells by the release of arachidonic acid from phospholipids of the cell membrane.