Carbonic anhydorase isoenzyme I (CA-I) concentration in feces and urine as a temporary marker of occult blood in beagle dogs.

This study was undertaken to investigate whether the concentration of carbonic anhydorase isoenzyme I (CA-I) in canine feces and urine is useful as a temporary marker of occult blood. Concentrations of CA-I were measured by enzyme-linked immunosorbent assay (ELISA). Fecal CA-I concentrations in 113 healthy beagle dogs (50 male and 63 female) of various ages ranged from 4.3 to 16.7 ng/g feces (mean; 7.0 +/- 2.9 ng/g feces). One milliliter of blood from 3 healthy beagle dogs was found to contain 1,047, 1,062 and 1,150 microg CA-I. The fecal CA-I concentrations of dogs receiving intragastric infusions of autologous blood (10 ml) were very low. However, the fecal CA-I concentrations of dogs receiving infusion of autologous blood (5 ml) into the ascending colon were very high. Detection of fecal CA-I would be useful for identifying dogs with hemorrhaging of the large intestine. Of 55 urinary samples collected from healthy beagle dogs by catheter, chemical tests for occult blood were negative in 44, but CA-I concentrations ranged from 1.8 to 12.6 ng/ml (mean; 6.9 +/- 5.4 ng/ml) by ELISA. The CA-I concentrations of the other 11 samples, which tested positive for occult blood on chemical testing, ranged from 41.2 to 525.0 ng/ml by ELISA. Although CA-I is not a specific marker of erythrocytes, CA-I may be used to detect occult blood in canine feces and urine until a specific immunological test kit using antibody for Hb is developed.     

Expression of the epithelial marker E-cadherin by thyroid C cells and their precursors during murine development.

Studies of chick-quail chimeras have reported that avian ultimobranchial C cells originate from the neural crest. It has consequently been assumed, without much supporting evidence, that mammalian thyroid C cells also originate from the neural crest. To test this notion, we employed both Connexin43-lacZ and Wnt1-Cre/R26R transgenic mice, because their neural crest cells can be marked. We also examined the immunohistochemical expression of a number of markers that identify migratory or postmigratory neural crest cells, namely, TuJ1, neurofilament 160, nestin, P75NTR, and Sox10. Moreover, we examined the expression of E-cadherin, an epithelial cell marker. At embryonic day (E)10.5, the neural crest cells densely populated the pharyngeal arches but were not distributed in the pharyngeal pouches, including the fourth pouch. At E11.5, the ultimobranchial rudiment formed from the fourth pouch and was located close to the fourth arch artery. At E13.0, this organ came into contact with the thyroid lobe, and at E13.5, it fused with this lobe. However, the ultimobranchial body was not colonized by neural crest-derived cells at any of these developmental stages. Instead, all ultimobranchial cells, as well as the epithelium of the fourth pharyngeal pouch, were intensely immunoreactive for E-cadherin. Furthermore, confocal microscopy of newborn mouse thyroid glands revealed colocalization of calcitonin and E-cadherin in the C cells. The cells, however, were not marked in the Wnt-Cre/R26R mice. These results indicated that murine thyroid C cells are derived from the endodermal epithelial cells of the fourth pharyngeal pouch and do not originate from neural crest cells.     

The antibacterial activity of plaunotol against Staphylococcus aureus isolated from the skin of patients with atopic dermatitis.

Plaunotol was tested for possible antibacterial activity against twenty strains of methicillin-resistant Staphylococcus aureus (MRSA) and fourteen strains of methicillin-sensitive S. aureus (MSSA) which had been isolated from the skin of patients with atopic dermatitis under growth-promoting conditions. Plaunotol was effective against all strains tested. The dose of plaunotol for 50% inhibition of growth (ID50) ranged from 2.5 to 16 micrograms/ml for strains of MRSA and from 2.5 to 7.0 micrograms/ml for those of MSSA. These results suggest that plaunotol may be useful in the prevention of infection by MRSA and in skin care for patients with atopic dermatitis.     

The 21-kDa Polypeptide (VAP21) in the Rabies Virion Is a CD99-Related Host Cell Protein

In our monoclonal antibody (MAb) stocks prepared against the BHK-21 cell antigens, two (#11875 and 28276) recognized a 21-kDa polypeptide (referred to as VAP21) which is efficiently incorporated into the rabies virion. By using these MAbs, we isolated the cDNA clones that encoded a polypeptide of 144 amino acids from our BHK-21 cell cDNA library. Based on the following evidence, the cDNA was assumed to encode a full-length sequence of VAP21 antigen: i) expression of the cDNA in animal cells resulted in the production of a polypeptide recognized by the two MAbs, and its electrophoretic mobility was the same as that of authentic VAP21 antigen; and ii) immunization with the products from the cDNA-transformed E. coli cells raised specific antibodies in rabbits that recognized a 21-kDa polypeptide in the virion. From the deduced amino acid sequence, it is suggested that the VAP21 antigen has a molecular structure of type-I transmembrane protein containing characteristic proline-rich and glycine-rich regions in its ectodomain. Homology searches resulted in finding homologous sequences (totally about 40% homology) in the human MIC2 gene product (CD99; 32-kDa) of T lymphocytes. These results suggest that the VAP21 antigen in the rabies virion is a cellular CD99-related transmembrane protein.     

Detection of HIV-Gag p24-Specific Antibodies in Sera and Saliva of HIV-1-Infected Adults and in Sera of Infants Born to HIV-1-Infected Mothers

Secretory immunoglobulin A (IgA) is known to play an important role in the mucosal defense against a variety of pathogens. Although the role of IgA antibodies during sexual transmission of HIV is not clear, HIV-specific IgA antibodies have been detected in various mucosal secretions of HIV-infected individuals. Using a monoclonal antibody against human IgA, we established an ELISA system to detect anti-HIV p24 IgA antibodies in sera and saliva. We have analyzed the levels of anti-HIV p24 IgG and IgA antibodies in sera and saliva of 107 and 119 adults, respectively, with HIV infection at different clinical stages, and in the sera of 13 infants born to HIV-infected mothers. The level of anti-HIV p24 IgA antibodies was lower in sera and higher in saliva as compared to that of anti-HIV p24 IgG antibodies. Where the percentage of HIV-specific serum antibody-positive cases decreased with disease progression, that of saliva antibody-positive cases increased in AIDS patients. Among the 13 infants born to HIV-infected mothers, 7 infants were HIV-p24-specific serum IgA positive. These sera were negative for anti-HIV p24 secretory IgA, suggesting that some infants develop their own immune responses against HIV infection. Thus, the detection of HIV-specific IgA antibodies, especially in saliva, could be a simple and reliable test for the diagnosis of HIV infection.     

Regulatory processes and population cyclicity in laboratory populations ofAnagasta kühniella (Zeller) (Lepidoptera: Phycitidae) IV. The sequential steps in the behavioral process of host finding and parasitization by the entomophagous parasite,Venturia canescens (Gravenhorst) (Hymenoptera: Ichneumonidae)

Summary The sequential steps in the behavioral process of a California stock of the entomophagous parasite,Venturia canescens (Grav.), parasitizingAnagasta kühniella (Zeller) was studied. In host-habitat finding, food media infested with hosts were very attractive to the parasites. Host finding was not covered in detail in this paper as it is presented in subsequent papers. Briefly, in all experiments host density was the most influential factor affecting the efficiency of the parasite. When three age stages of the host were exposed to a parasite, all tests showed that the large, last instar larvae was the preferred age stage but it was not the most suitable (when parasitized) for successful parasite development. Small larvae were less preferred but more suitable for parasite development when accepted. These studies were conducted as a partial fulfillment in the Ph. D. program of one of us (B. M. Matsumoto) and form a part of a broad investigation into the processes operating in the dynamics of arthropod populations under grants toC. B. Huffaker from the U. S. Public Health Service, National Institutes of Health and the U. S. Department of Agriculture.     

Studies of Electric Capacitance of Membranes: I. A Model Membrane Composed of a Filter Paper and a Lipid Analogue

A hydrophobic filter paper of a given pore size containing a synthetic lipid, i.e. dioleyl phosphate, was interposed between aqueous electrolyte solutions having the same chemical composition and temperature. The electric capacitance and conductance of the membrane immersed in various concentrations of KCl were measured in the frequency range from 20 to 3 × 10⁶ cycle/sec. The observed capacitance and conductance were found to be strongly dependent on the applied frequency. A theory is proposed to account for this dispersion of impedance observed in the present membrane-electrolyte system. The dispersion is attributed to the formation of bilayer membranes of the lipid inside the filter paper. The effects of the salt concentration, the adsorbed quantity of the lipid, and the pore size of the filter paper on the capacitance and conductance of the membrane are discussed in terms of the distribution function of bilayers formed within the filter paper.