Inhalation Teratology Studies of n-Butyl Mercaptan in Rats and Mice

Inhalation Teratology Studies of n-Butyl Mercaptan in Rats andMice. THOMAS, W. C., SECKAR, J. A., JOHNSON, J. T., ULRICH,C. E., KLONNE, D. R., SCHARDEIN, J. L., AND KIRWIN, C. J. (1987).Fundam. Appl. Toxicol. 8, 170–178. n-Butyl mercaptan (n-BM)is used as a solvent and a chemical intermediate. Pregnant CharlesRiver CD-1 mice and COBS CD rats were randomly assigned to acontrol group and to three n-BM-exposed groups of 25 rats and25 mice each. The animals were exposed by whole-body inhalationto mean n-BM concentrations of 10, 68, or 15 2 ppm on a 6-hrdaily exposure schedule. Rats were exposed on Gestation Days6–19 and mice on Gestation Days 6–16. The controlgroup was exposed to filtered air only on a comparable regimen.Cesarean sections were performed on all surviving mice on GestationDay 17 and on all rats on Gestation Day 20. Seventeen of then-BM-treated mice died: 8 at the 68-ppm level and 9 at the 152-ppmlevel; none of the n-BM-treated rats died. An increased postimplantationloss and increased early resorption occurred in mice exposedat 68 and 152 ppm, indicating embryotoxicity. An increased incidenceof cleft palate was observed in mice exposed to 10 or 68 ppmwhich was not statistically significant. Total fetal abnormalitieswere statistically significantly different from controls at68 ppm where maternal lethality was observed when based on thefetal unit although not when based on the litter unit. Ratsexposed to 152 ppm or less demonstrated no terata.     

Presence of an Endothelial Antigen on the Syncytiotrophoblast of Human Chorionic Villi: Detection by a Monoclonal Antibody

ABSTRACT: We describe a monoclonal antibody, B721. This antibody reacts with an antigen present on vascular endothelium and on the syncytiotrophoblast of term chorionic villi. The antigen is absent from the trophoblast of the chorion, from the amniotic epithelium, and from normal peripheral blood or lymph node lymphocytes. We discuss the possible functional roles of the antigen. We propose that the syncytiotrophoblast, by expressing endothelial antigens, mimics endothelium and may perform endothelial functions.     

A Comparative Analysis of Cell Surface Markers on Murine NK Cells and CTL Target-Effector Conjugates

The rosetting of sheep erythrocytes (SRBC) coated with non-haemagglutinating monoclonal antibodies rather than conventional haemagglutinating antisera revealed readily detectable FcR on most splenic natural killer (NK) cells since 76% of splenic lymphocytes forming conjugates with YAC also resetted with SRBC coated with high concentrations of monoclonal anti-SRBC antibody of the IgG2b subclass and since Ficoll depletion or enrichment of splenic lymphocytes rosetting with IgG2b-coated SRBC resulted in a corresponding 4-fold decrease or increase in conjugate-forming cells and a 10-fold decrease or increase in NK cytolytic acttvity. NK cells bound much less readily to monoclonal IgG2a and not at all to monoclonal IgGI or IgM, but the degree of binding was directly proportional to the amount of antibody on the erythrocytes and was not isotype-restricted. In addition, immunofluorescent studies revealed that YAC-1-conjugated lymphocytes were Lyt-1^-, Lyt-2^-, partially Thy-1⁺ (60%), asiato-GMI ⁺ (80%), Qa-4⁺ (77%), Qa-5⁺ (79%), and Ly-5⁺ (94%). In comparison, a proportion (39%) of alloimmune peritoneal exudate cells which conjugated with P815–2 also siained by immunofluorescence with anti-asialo GM1 antisera. Most (>90%) P815- conjugated cells were Thy-1⁺, Lyt-2⁺. and a subpopulation of Lyt-l⁺2⁺ conjugates was observed (25 %). Qa-5 and Ly-5 were also expressed on most (two-thirds) cytolytic T lymphocytes (CTL) conjugates, whereas Qa-4 and FcR for IgG2b were not detected. The best phenotypic distinctions between NK cells and CTL were therefore based on the presence or absence of Lyt-2, Qa-4, and FcR for IgG2b on most effector cells. Anti-asialo-GMl or monoclonal anti-Qa-4 and complement treatment greatly diminished both the frequency of NK conjugates and the percentage of conjugates with detectable IgG2b FcR or asialo-GM1. These results confirm that NK cells co-express asialo-GMI and Fc receptors, at the single-celt level, and provide a simple method for greatly enriching NK populations at least 10-fold.     

The effects of an acute psychological stressor on cardiovascular, endocrine, and cellular immune response: A prospective study of individuals high and low in heart rate reactivity

High and low reactors were preselected on the basis of their heart rate reactivity to a speech stressor in a prescreening session. In the main study, subjects were exposed to a mental arithmetic plus noise stressor. Cardiovascular activity was recorded during baseline and stressor, and blood was drawn prior to and following the stressor for endocrine and immune assays. Results revealed that the stressor decreased the blastogenic response to concanavalin A and increased natural killer cell numbers and cytotoxicity, absolute numbers of CD8⁺ T-lymphocytes, nor-epinephrine and epinephrine levels, heart rate, and blood pressure responses. In addition, cortisol and natural killer cell cytotoxicity responses to the stressor differentiated individuals high versus low in heart rate reactivity. These results suggest that the interactions among the autonomic nervous system, endocrine system, and immune system are not only amenable to psychophysiological analysis but that such analyses may play an important role in illuminating underlying mechanisms.     

THE EFFECTS OF EXTRACELLULAR MATRIX AND OSTEOGENIC PROTEIN-1 ON THE MORPHOLOGICAL DIFFERENTIATION OF RAT SYMPATHETIC NEURONS

The growth patterns of axons and dendrites differ with respect to their number, length, branching, and spatial orientation; therefore, it is likely that these processes differ in their growth requirements. To examine this hypothesis, we have been analyzing the responses of cultured rat sympathetic neurons to three types of stimuli: large structural proteins of the extracellular matrix, matrix-associated growth factors, and neurotrophins. Purified structural proteins such as laminin and collagen IV have been found to promote only axonal growth; whereas the matrix associated growth factor, osteogenic protein-1, selectively stimulates dendritic growth. In contrast, nerve growth factor modulates the growth of both types of processes. These data suggest that process-specific interactions with the extracellular environment may be critical determinants of cell shape in neurons. Perinatal rat sympathetic neurons grown in culture in the absence of serum or glial cells extend a single process which is axonal in nature. Exposure to osteogenic protein-1 causes the formation of additional processes which express the morphological, cytoskeletal, and ultrastructural characteristics of dendrites. Consistent with observations on the regulation of dendritic growth in sympathetic neurons in situ, the dendrite-promoting activity of osteogenic protein-1 is independent of synaptic or electrical activity, but is modulated by nerve growth factor. In the presence of optimal concentrations of osteogenic protein-1 and nerve growth factor, the size of the dendritic arbor extended by cultured sympathetic neurons approximates that seen in situ at comparable developmental stages. Osteogenic protein-1 does not promote dendritic growth in cultured neurons obtained from embryonic ciliary, dorsal root, trigeminal or nodose ganglia, suggesting that its morphogenetic effects are cell selective. Since mRNA for osteogenic protein-1 is expressed in mature as well as embryonic target tissues of the sympathetic nervous system, we also examined the effects of osteogenic protein-1 on cultures of sympathetic neurons derived from adult rats. Consistent with results obtained with perinatal neurons, osteogenic protein-1 selectively promoted dendritic growth in adult neurons. These data suggest that this matrix-associated growth factor could play a role not only in the morphogenesis of the developing nervous system, but also in the maintenance and remodeling of dendritic structures in the mature animal. Copyright © 1996 ISDN. Published by Elsevier Science Ltd.     

Prospective, Randomized, Blinded Study of a New Wound Closure Film Versus Cutaneous Suture for Surgical Wound Closure

BACKGROUND Wound closure devices include sutures, tissue adhesives, adhesive strips, and staples. Recent studies suggest no differences between various tissue adhesives and sutures for dehiscence, infection, and satisfaction when assessed by patients or surgeons. To date, no studies have investigated ClozeX (Clozex Medical LLC, Wellesley, MA, USA), a novel adhesive strip, for closure of surgical incisions.
OBJECTIVE To compare surgical wounds repaired with ClozeX versus suture.
METHODS A prospective, randomized study was conducted, in which 15 patients with surgical incisions were allocated to closure with ClozeX on half of the wound and monofilament suture on the other half. Physician satisfaction with blinded assessment, patient satisfaction, complication rates, and closure times were recorded.
RESULTS Application with ClozeX was faster than with suture ( p =.007). There were no complications in either group. Sixty-nine percent of the patients gave ClozeX a higher satisfaction score ( p =.02). More physicians were satisfied with the ClozeX half than with the suture half ( p =.007).
CONCLUSIONS This pilot study demonstrates ClozeX to be a safe and effective closure device. The cosmetic outcome seems to be at least as good as simple running suture. Physicians and patients were generally more satisfied with ClozeX. No difference was found in the rate of dehiscence or infection between the groups.     

Design and inhibitory properties of synthetic Bowman-Birk loops

A cyclic tridecapeptide based on the sequence of an anti-tryptic loop of a Bowman-Birk inhibitor was synthesized, and demonstrated to be active as an inhibitor of trypsin. Molecular modeling of this sequence suggested an improved sequence which demonstrated an order of magnitude improvement in the inhibitory constant.     

Gastric Mucosal Lacerations from Blunt Trauma to the Abdomen

A 17-year old, Caucasian male, high school student sustained gastric mucosal lacerations from blunt trauma to the abdomen during a football game with associated severe upper gastrointestinal bleeding. The lacerations were diagnosed by endoscopy and treated conservatively with uneventful, rapid and complete recovery.