Altered clearance of inhaled 99mTc-pentetate aerosols following exposure to cadmium chloride aerosols in ferrets

The rate of clearance of inhaled 99mTc-pentetate aerosols has been used as an indicator of pulmonary epithelial "permeability" in human and animal studies. In order to evaluate this technique further, groups of eight male ferrets (Mustela putorius furo) were given acute exposures to aerosols of CdCl2 or NaCl via endotracheal tube. Serial evaluations of the thoracic clearance rate of inhaled 99mTc-pentetate aerosols (MMAD = 0.6 microns, sigma g = 1.6) were made before exposure and at fixed time points after toxicant exposure (3 or 6, 24, 48 h, and 5 days after CdCl2). These serial evaluations of 99mTc-pentetate thoracic clearance were conducted at three cadmium intake levels (3, 10, and 30 min exposure to 10 mg/m3 CdCl2) in order to evaluate possible dose-related response relationships. The rate of thoracic clearance of Tc-pentetate was observed to be slowed at 3 h after exposure to CdCl2 aerosol and subsequently increased to well above control rates. The time sequence observed strongly suggests that increased Tc-pentetate clearance rates are indicative of a tissue response or repair process, rather than acute lung injury. Tracheal epithelial penetration of macromolecular tracers was not observed to increase in histological evaluations following serial sacrifice.     

Diminished virucidal activity of kethoxal against vesicular stomatitis virus pretreated with guanidinating reagent and proteases.

The reactivity of vesicular stomatitis virus (VSV) with kethoxal can be appreciably altered by treatment with 1-guanyl-3, 5-dimethyl pyrazole nitrate (GDMP) and proteolytic enzymes. Pretreatment of purified VSV with GDMP or proteolytic enzymes markedly reduced the effectiveness of kethoxal as a virucide. The rate of neutralizability of GDMP- and trypsin-treated viruses by specific antiserum differed from that of controls.     

Performance of a commercial, type-specific enzyme-linked immunosorbent assay for detection of herpes simplex virus type 2-specific antibodies in Ugandans

Two hundred forty-eight human immunodeficiency virus (HIV)-positive and 496 HIV-negative subjects in Uganda were tested by HerpeSelect herpes simplex virus type 2 enzyme-linked immunosorbent assay (ELISA) and Western blotting to optimize the ELISA for use in this population. A higher index cutoff value was required for optimal sensitivity and specificity, and overall performance of the assay was not affected by HIV status.     

Cytogenetic studies of familial and sporadic Alzheimer disease

We present cytogenetic findings in 7 familial and 5 sporadic Alzheimer disease (AD) patients and 34 unaffected relatives, spouses, and normal controls. Our study was prompted by reports of increased chromosome abnormalities in patients and family members at risk for AD. Coded peripheral blood chromosome preparations were evaluated for aneuploidy, aberration rates, and banding patterns. Statistical analyses of our results showed no increase in aneuploidy or aberrations in AD patients, their relatives, or normals. Chromosome loss or gain in aneuploid cells was not specific except in two individuals. These two older persons studied, one with AD and one unaffected, were observed to have increased sex chromosome aneuploidy. This finding was attributed to aging and was not considered to be an effect of AD.     

Antimicrobial resistance of Salmonella isolates from swine

We examined the antimicrobial resistance of 1,257 isolates of 30 serovars of Salmonella enterica subsp. enterica isolated from swine. Serovars Typhimurium and Typhimurium var. Copenhagen were widespread and were frequently multidrug resistant, with distinct resistance to ampicillin, kanamycin, streptomycin, sulfamethoxazole, and tetracycline and to ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracycline, respectively.     

Synthetic peptides from a conserved region of gp120 induce broadly reactive anti-HIV responses.

In our efforts to identify products that might be used for active immunotherapy in human immunodeficiency virus (HIV) infection, we have studied synthetic peptides derived from the CD4 attachment site of gp120. Two peptides have emerged with particularly interesting properties. The first (B138) is linear and spans the envelope residues 421-438; the second (1005/45) encompasses amino acids 418-445 and is cyclized by way of a disulphide bond joining its terminal cysteines. Both species have been shown to inhibit syncytial formation in a conventional bioassay, B138 being the most efficient. Both peptides elicit high titres of anti-peptide antibodies in immunized mice, rabbits and goats, with titres exceeding 1:10(5) in many cases. A substantial portion of this response is directed against gp120 as determined by enzyme-linked immunosorbent assay (ELISA). Analysis by flow cytometry has demonstrated that the antisera are broadly reactive with multiple diverse strains of HIV. The anti-gp120 activity of the anti-peptide antiserum was further confirmed by radioimmuno-precipitation (RIP) assays. Furthermore, RIP analysis and inhibition experiments in a GD4-gp120 binding assay have revealed that anti-peptide sera contain antibodies directed against the CD4 attachment site on gp120 and interfere with this receptor-ligand interaction.     

The effects of head and trunk position on torsional vestibular and optokinetic eye movements in humans

We measured torsional vestibular and optokinetic eye movements in human subjects with the head and trunk erect, with the head supine and the trunk erect, and with the head and trunk supine, in order to quantify the effects of otolithic and proprioceptive modulation. During active head movements, the torsional vestibulo-ocular reflex (VOR) had significantly higher gain with the head upright than with the head supine, indicating that dynamic otolithic inputs can supplement the semicircular canal-ocular reflex. During passive earth-vertical axis rotation, torsional VOR gain was similar with the head and trunk supine and with the head supine and the trunk erect. This finding implies that static proprioceptive information from the neck and trunk has little effect upon the torsional VOR. VOR gain with the head supine was not increased by active, self-generated head movement compared with passive, whole body rotation, indicating that the torsional VOR is not augmented by dynamic proprioceptive inputs or by an efference copy of a command for head movement. Viewing earth-fixed surroundings enhanced the torsional VOR, while fixating a chair-fixed target suppressed the VOR, especially at low frequencies. Torsional optokinetic nystagmus (OKN) evoked by a full-field stimulus had a mean slow-phase gain of 0.22 for 10°/s drum rotation, but gain fell to 0.06 for 80°/s stimuli. Despite this fall in gain, mean OKN slow-phase velocities increased with drum speed, reaching maxima of 2.5°/s–8.0°/s in our subjects. Optokinetic afternystagmus (OKAN) was typically absent. Torsional OKN and OKAN were not modified by otolithic or proprioceptive changes caused by altering head and trunk position with respect to gravity. Torsional velocity storage is negligible in humans, regardless of head orientation.Presented in part at the Society for Neuroscience Annual Meeting, October 31, 1989, Phoenix, AZ     

Variable expression of a surface determinant during proliferation of Candida albicans.

The surface expression of an antigenic determinant that is present in the cell wall of Candida albicans was investigated with monoclonal antibody 24 (MAb24), an immunoglobulin M MAb. The proportion of the cell population that expressed the epitope under different growing conditions was determined by indirect immunofluorescence microscopy. More than 90% of stationary-phase yeast cells of strain B311 grown at 28 degrees C expressed the antigen. Less than 50% of yeast cells grown exponentially at 28 degrees C or either growing or stationary-phase yeast cells cultivated at 37 degrees C expressed the epitope. Germ tubes, which were induced at 37 degrees C from stationary-phase yeast cells grown at 28 degrees C, expressed the determinant on the parent yeast but not the hyphal portion of the germ tube. The change in antigen expression by stationary-phase cells grown at 28 degrees C, when they resumed growth by bud formation, suggested that antigen expression was lost by cells in the inoculum prior to the first cell division. By using the same assay, strong positive reactions were observed in stationary-phase cultures of other isolates of C. albicans, C. guilliermondii, C. stellatoidea, and C. tropicalis, but not with isolates of C. krusei, C. parapsilosis, or Torulopsis glabrata. The identification of the antigenic determinant as a carbohydrate was based on three observations: (i) interaction with a mannan preparation from the same organism, (ii) sensitivity of the antigen to periodate but not proteases, and (iii) coincidence of the migration of antigen during electrophoresis with material which stained intensely with carbohydrate but not with protein reagents. These observations suggest that the expression of the antigenic determinant of MAb24 is dependent on the growth conditions, growth state, and morphology of the cell and that the topography of the cell surface is dynamic.