Biodegradable lysine diisocyanate-based poly(glycolide-co-epsilon-caprolactone)-urethane network in artificial skin

A biodegradable lysine diisocyanate-based poly(glycolide-co-epsilon-caprolactone)urethane network has been evaluated as a material for the construction of a macroporous bottom layer (dermal analogue) in a two-layer artificial skin. High rates of in vitro degradation were observed; degradation of the porous poly(glycolide-co-epsilon-caprolactone)urethane networks was faster in vivo than in vitro. Subcutaneous implantation in guinea pigs showed that the porous polyurethane networks allowed rapid cell ingrowth, degraded almost completely 4-8 wk after implantation and evoked no adverse tissue reaction.     

Tissue response to allergenic leachables from dental materials

In addition to toxic reactions to dental materials, some individuals may develop or exhibit hypersensitivity reactions to leachable components. An experimental model combining the guinea pig maximization test for induction of hypersensitivity and the subcutaneous implantation of dental cements is described. Guinea pigs immunized with AH 26, an epoxy-bisphenol resin, showed an increased tissue response to AH26 implants. Guinea pigs immunized with zinc oxide-eugenol did not show a similarly increased response, possibly because of an anti-inflammatory effect of eugenol. The experimental model may prove useful in predicting the effect of leachable allergens from dental materials in sensitized individuals.     

Preliminary studies of the histopathological responses to Ti-13% Cu casting alloys

A preliminary study of some of the biological properties of a new dental casting alloy (Ti-13% Cu) was undertaken by employing the skeletal muscle implantation test in rabbits. Routine histopathological and chemical analysis techniques were utilized to study in vivo tissue reactions of skeletal muscle to this alloy. A moderately thick, somewhat cellular fibrous connective tissue capsule surrounded the implants after 2 wk. Remodelling of the fibrous tissue into a thin acellular tissue capsule occurred at 52 wk after implantation. Chemical analyses failed to detect deposition of either Ti or Cu corrosion products at the implant sites or within major organs.     

Antigen-induced elevation of immunoreactive endothelin-1 (ET-1) levels in ovalbumin-sensitized guinea pig airway tissue

Changes in the immunoreactive ET-1 levels during the anaphylactic reaction of airway tissue from ovalbumin-sensitized guinea pigs were investigated. ET-1-immunoreactivity (ET-IR) was detected in the epithelial and smooth muscle layers of tracheal sections from normal guinea pigs and it was enhanced slightly by phosphoramidon (1 microM) treatment. The ET-IR level of the epithelial layer of ovalbumin-treated tissue from actively sensitized animals was slightly higher than that from normal animals, but it was enhanced markedly by phosphoramidon (1 microM) treatment. Furthermore, the mean ET-IR level of homogenates of antigen-treated tracheal tissues from sensitized guinea pigs (22.8 +/- 1.55 fmol mg-1 protein, n = 5) was significantly higher than the corresponding normal level (12.3 +/- 1.21 fmol mg-1 protein, n = 5). These results suggest that increased epithelial airway ET-1 levels contribute to the anaphylactic reaction of guinea pig airways.     

镍钛合金听泡植入对豚鼠耳蜗及听功能的毒性

背景：镍钛合金多作为自膨胀支架和封堵器的材料应用已很成熟,但镍钛合金作为听骨链重建材料的相关研究及临床应用至今少有报道。 目的：观察镍钛合金植入体在豚鼠听泡中的耳毒性。 方法：健康听敏纯白红目豚鼠50只,每只豚鼠其中一侧耳为镍钛合金植入组,其中25只对侧耳为钛植入组,另25只对侧耳为空白植入组。分别于植入后7,14,28,56,112 d随机处死含钛植入组和空白植入组的豚鼠各5只,对各组行近中轴位耳蜗石蜡切片苏木精-伊红染色观察耳蜗组织的形态变化,行耳蜗毛细胞核丫啶橙-碘化丙啶双重荧光染色观察毛细胞凋亡和缺失情况,行耳蜗基底膜扫描电镜观察毛细胞纤毛排列情况,透射电镜观察毛细胞细胞器形态,对各组的豚鼠植入前、不同时间点处死前均行听性脑干反应及畸变反应耳声发射检测。 结果与结论：各组植入后各时间点耳蜗组织形态无明显变化,未发现耳蜗毛细胞发生凋亡,基底膜耳蜗毛细胞纤毛排列整齐,外耳蜗毛细胞的细胞器未见明显异常。植入前及植入后7,14,28,56,112 d听性脑干反应阈值差异无显著性意义,且畸变反应耳声发射检测通过率均为100%。结果证实,镍钛合金听泡植入对豚鼠耳蜗形态及听功能无明显影响,提示镍钛合金无明显耳毒性。中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程全文链接：     

The allogeneic effect: increased affinity of serum antibody produced during a secondary response

We have used the “allogeneic effect” as a model system for investigating the effects of augmented thymus-derived lymphocyte function on secondary antibody responses of primed inbred guinea pigs. A transient graft-versus-host reaction was induced by infusing nonimmune strain 13 lymphoid cells into strain 2 guinea pigs which had been primed with dinitrophenylated (DNP) ovalbumin. Six days later the recipients were challenged with the priming antigen intradermally. Four days after boosting with antigen, sera from these “allogeneic” guinea pigs had significantly higher affinity for ε-DNP-L -lysine than sera from “control” guinea pigs which were primed, but had not received allogeneic lymphoid cells. Spleen cells taken from “allogeneic” guinea pigs three to five days after boosting were shown to have both higher numbers of plaque-forming cells and a predominance of high avidity antibody-producing cells in comparison to spleen cells from “control” guinea pigs. Thus, increased donor thymus-derived lymphocyte function brought about by the transient graft-versus-host reaction causes an enlargement of the host antibody-producing cell pool and preferentially expands the subpopulation of cells producing high affinity antibody. The effects of this preferential expansion are reflected in the sera of “allogeneic” guinea pigs as higher affinity antibody in comparison to serum antibody of “control” guinea pigs.     

In vitro and in vivo biological responses to some dental alloys tested separately and in combinations

Biocompatibility of dental alloys has been tested both in vivo and in vitro. In addition, combinations of dissimilar alloys were investigated in relation to possible enhanced corrosion by galvanic effects. Implantation tests, cytotoxicity tests on epithelial cells, macrophages and erythrocytes were performed, and the results compared. The severity of tissue response in implantation tests corresponded to the nobleness of the casting alloys joined to amalgam. Similar results were obtained in the in vitro macrophage test. All the alloys except the high-gold alloy (LM-Hard) had a toxic effect on epithelial cells. The combination of the casting alloys with amalgam diminished the toxic effect. Three of the alloys (amalgam, LM-Hard and Midi low-gold alloy) caused a slight haemolysis. Poor correlation was obtained between the agarose overlay tests, the haemolysis tests and the implantation tests.     

Experimental infection and immune response of guinea pigs with varicella-zoster virus.

An immune response (fluorescent antibody to membrane antigen) was detected in guinea pigs inoculated with varicella-zoster virus (VZV) adapted to guinea pig embryonic cells, including the Oka vaccine strain, even when inoculation was by an external route, i.e., nasal or corneal. Live or UV-inactivated virus having the same virus titer before irradiation was administered to guinea pigs by the corneal route, and antibody induction was detected only with live virus. The transmission of VZV from infected guinea pigs to noninfected ones was suggested by the appearance of antibody in the serum of the latter, who were kept in the same cage. The time course of the appearance of humoral and cellular immune responses in guinea pigs was examined by the fluorescent antibody to membrane antigen test and the skin reaction, with varicella antigen representing delayed-type hypersensitivity. When VZV was injected subcutaneously, skin reaction appeared as early as 4 days after inoculation, which preceded the appearance of detectable antibody by 2 to 6 days. In in vitro studies, the Oka vaccine showed a higher adsorption rate and better growth in guinea pig embryonic cells than did other wild-type strains when assayed by the infectious center assay. These results suggest that a system of VZV adapted to guinea pig cells and guinea pigs provides a good animal experimental model for immunological study of VZV infection.     

Transforming growth factors-beta 1 and beta 2 induce synthesis and accumulation of hyaluronate and chondroitin sulfate in vivo.

Subcutaneous implantation in rats of partially purified transforming growth factor-beta (TGF-beta) derived from bovine bone induced extensive development of connective tissue with associated edema. Subcutaneous injection of pure TGF-beta 1 or TGF-beta 2 also induced connective tissue deposition in mice and guinea pigs. Sustained release of TGF-beta 1 from mini-osmotic pumps implanted subcutaneously in mature guinea pigs promoted connective tissue deposition that encapsulated the pumps. Biochemical analyses of the connective tissue capsule demonstrated that TGF-beta 1 induced a dose-dependent accumulation of glycosaminoglycans (GAGs). The GAG/DNA ratio also increased as a function of the rate of TGF-beta 1 released, suggesting that the factor increased production of GAGs per cell. Cellulose acetate gel electrophoresis of the GAGs and hydrolysis with specific glycosidases revealed that the majority of GAGs consisted of hyaluronate and chondroitin sulfate. These results demonstrate that TGF-beta 1 and TGF-beta 2 stimulate the production of not only collagenous extracellular matrix components, but also dramatically increase the in vivo synthesis of hyaluronate and chondroitin sulfate.     

Studies on sperm antigenicity. I. Delayed hypersensitivity to spermatozoa

Delayed hypersensitivity to human and guinea pig sperm was demonstrated in guinea pigs of the Rockefeller strain by immunization with H₃₇Ra adjuvant. The reaction in vivo was demonstrated by skin testing the animals and in vitro by the capillary method. It was found that the sensitivity is not only directed towards the sensitizing antigen, but also shows cross-reactivity. Thus, peritoneal exudate cells derived from guinea pigs sensitized to human sperm were inhibited by guinea pig sperm. This cross-reactivity revealed the possibility of a tissue specific antigen. In addition, supernatants obtained after incubation of the sensitized lymph node cells with the specific antigen were found to be spermatotoxic.     

An Outbreak of Infection by Yersinia pseudotuberculosis in Nonhuman Primates

Between October 1970 and June 1971, at the National Center for Primate Biology, Yersinia pseudotuberculosis of serotypes I-B and III was isolated from 9 monkeys (one during life and 8 at necropsy) of the following species: Macaca cynomolgus, Macaca nemestrina, Macaca radiata and Cercocebus fulliginosus. All these animals had characteristic gastrointestinal lesions consisting of superficial erosions or ulcerations with masses of gram-negative coccobacilli and an acute inflammatory exudate. Involvement of mesenteric nodes, livers and spleens by similar lesions was common. A more granulomatous reaction was rarely seen. Similar lesions without bacteriologic confirmation were found at necropsy in 20 other animals. When guinea pigs were inoculated intraperitoneally with our isolates, they developed focal splenic and hepatic necrosis resembling the septicemic form of the disease which is seen rarely in man. When inoculated intraperitoneally, they developed mesenteric lymphadenitis resembling human nonspecific mesenteric lymphadenitis; no intestinal lesions could be detected in the animals inoculated orally. The granulomatous component of the inflammatory response was better developed in guinea pigs than in the monkeys. It is concluded that infection by Yersinia pseudotuberculosis in nonhuman primates and probably also in other species, including man, is primarily a gastrointestinal disease. The primary intestinal lesions may be conspicuous, as in the monkeys, or inconspicuous, as in the guinea pig and man. The acuteness of the inflammatory response in the monkeys, when compared to the more granulomatous reaction in guinea pigs, suggests that the great majority of the monkeys died from an overwhelming infection before they could develop hypersensitivity to the organism.     

Experimental animal infections with Mycoplasma hominis and Ureaplasma urealyticum.

Subcutaneous tissue cavities in mice and guinea pigs were infected with human isolates of Ureaplasma urealyticum and Mycoplasma hominis. The minimal infective dose for M. hominis was as low as less than 10 color-changing units (CCU) for mice and 10(2) CCU for guinea pigs. The minimal infective dose for U. urealyticum was as low as less than 10 CCU for mice and 10(4) CCU for guinea pigs. Mouse infections with either U. urealyticum or M. hominis persisted for 1 day to greater than 4 months. Guinea pigs remained infected for up to 4 weeks. Two M. hominis isolates were similar in their ability to infect subcutaneous tissue cavities but two U. urealyticum isolates varied in their ability to infect the cavities. The histopathology of the M. hominis and U. urealyticum infections was similar: an initial intense polymorphonuclear response with giant cells, followed in 4 weeks by histiocytes and giant cells with some plasma cells and lymphocytes.     

人脐带胶在豚鼠眼睑原位重建中的应用

背景：健康新生儿脐带胶是一种无血管的黏液结缔组织,有一定的弹性和韧性,含有溶菌酶、胎盘球蛋白、透明质酸酶、AMP抗体和补体系统,不容易发生感染和排斥反应,还含有较多的间充质干细胞,临床已被用于眼部整形手术。 目的：观察脐带胶作为睑板替代物在豚鼠上眼睑重建中的组织相容性和组织病理变化。 方法：取健康新生儿脐带中的黏液结缔组织-脐带胶,制备成厚薄相近的组织块;同时制作豚鼠睑板全层缺损模型并植入脐带胶组织块,观察动物大体情况,分别于脐带胶植入后1,2,3周取其交界处眼睑组织,光镜下观察组织学改变。 结果与结论：所有动物在植入脐带胶材料后均未发生感染、脱位等情况,所有动物角膜上皮完整,无角膜上皮脱落。脐带胶代替睑板植入后1周时,结膜红润,切口无红肿等排斥反应发生,角膜上皮完整,眼睑运动可;脐带胶与肌肉间的炎性细胞浸润。植入后2周时结膜面红润,切口无红肿,无分泌物增多等排斥反应发生,角膜上皮完整,眼睑及眼球运动良好,无睑球粘连发生;脐带胶有溶解吸收倾向,炎性细胞不明显。植入3周时结膜切口愈合良好,角膜上皮完整,眼睑柔软,形态与对侧眼无明显区别;脐带胶部分吸收,其周边有新的纤维生成,无炎性细胞。说明脐带胶的免疫原性低,可引导新生胶原的生长,是一种良好的睑板替代物。中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程全文链接：     

Cecal toxin(s) from guinea pigs with clindamycin-associated colitis, neutralized by Clostridium sordellii antitoxin.

The cecal contents of guinea pigs with clindamycin-associated colitis contained a heat-labile toxin. This toxin was lethal for guinea pigs and mice, produced vascular permeability in the skin of rabbits, and was cytotoxic in tissue culture. The lethality in mice, vascular permeability in rabbit skin, and cytotoxicity in tissue culture monolayers were neutralized by Clostridium sordellii antitoxin.     

Estimation of guinea pig antigen-specific and non-specific suppressor cell activity

A functional assay for the quantitative estimation of suppressor cell (SC) activity in guinea pigs has been developed. Cultures of antigen-stimulated peripheral blood lymphocytes (PBL) from sensitized guinea pigs develop SC activity. The suppression of proliferation can be demonstrated in antigen-stimulated autologous co-cultures of precultured and freshly isolated PBL. The extent of suppression is dependent on the preculture antigen concentration but not the preculture period and it consists, as demonstrated with PBL from doubly sensitized guinea pigs, of an antigen-specific and a non-specific component. The observed SC activities were not due to an alteration of the kinetics of the co-cultures. The estimates of suppression are highly dependent on corrections for the values of the control cultures. The present method may prove useful in immunological studies of mycobacterial infections in guinea pigs.     

The inhibitory effect on passive cutaneous anaphylaxis in guinea pigs of oral administration of Corynebacterium (Rhodococcus) equi

We studied the inhibitory effect on the PCA reaction of BSA-rabbit anti-BSA (BSA-anti-BSA) system in CP-sensitized and CP-unsensitized guinea pigs by the oral administration of C. equi. Strain Ko-85 (Ko-85) cells. The results were as follows: 1) Guinea pigs were sensitized by intraperitoneal injection with the CP. Nine days later, the animals were administered with an oral dose of 80 mg (W.W.) of Ko-85 cells. The animals were submitted daily to PCA reaction tests using BSA and rabbit anti-BSA serum. The inhibition of PCA reaction of BSA-anti-BSA system in CP-sensitized guinea pigs was shown from 4th day to 10th day after administration of Ko-85 cells. The PCA reaction of 9th day was recognized strong inhibition by the oral administration of Ko-85 cells. 2) CP-unsensitized guinea pigs were given an oral dose of 80 mg of Ko-85 cells, and the animals were submitted every other day to PCA reaction tests of the BSA-anti-BSA system. PCA elicited in these animals on the 9th, 15th and 17th days Ko-85 administration were inhibited compared with those in the control animals (which were not given an oral dose of Ko-85 cells). The strongest inhibition was shown in animals challenged on the 15th day after Ko-85 administration. The inhibitory effect of PCA reaction of BSA-anti-BSA system by the oral administration of an oral dose 80 mg (W.W.) of Ko-85 cells was recognized in CP-sensitized and CP-unsensitized guinea pigs.     

Experimental chlamydial salpingitis in immunosuppressed guinea pigs infected in the genital tract with the agent of guinea pig inclusion conjunctivitis.

At necropsy indication of spread of infection to fallopian tubes was found in 25 of 41 (60%) female guinea pigs infected in the genital tract with the chlamydial agent of guinea pig inclusion conjunctivitis and immunosuppressed with cyclophosphamide. Eighteen were examined histologically, and the diagnosis of acute salpingitis was confirmed in 10, based on inflammatory reaction, detection of guinea pig inclusion conjunctivitis in tissue, and formation of cysts (pyosalpinx and hydrosalpinx). Infection of fallopian tube tissue was confirmed by indirect immunofluorescence and electron microscopy. Infection of endometrial tissue and peritoneum was also recognized. Data suggested that the immunosuppression mediated by cyclophosphamide resulted in a prolonged genital tract infection and concomitant ascending infection leading to salpingitis.     

Delayed-type hypersensitivity reaction in the lungs of guinea pigs due to potassium dichromate

Potassium dichromate was inhaled by guinea pigs previously immunized by potassium dichromate until strong positive patch tests were obtained. No obvious respiratory changes were noted during and after inhalation. Histologically, however, mononuclear cells infiltrated the interstitial spaces in large areas of the lung, producing considerable thickening of the alveolar spaces in 24 to 48 hr after inhalation. Polymorphonuclear cells were predominant initially. These changes were similar to the delayed-type hypersensitivity reaction in the lung elicited by the inhalation of purified protein derivative (PPD) in the guinea pigs immunized by an injection of dry-killed tubercle bacilli. A less marked reaction was observed in guinea pigs passively sensitized with peritoneal exudate cells and lymph node cells. Consequently, the pulmonary changes were thought to be elicited by delayed-type hypersensitivity reaction due to a simple chemical. The clinical implications of delayed-type hypersensitivity reaction in the lung due to simple chemicals are discussed.     

Adoptive transfer of immunity to Treponema pallidum Nichols infection in inbred strain 2 and C4D guinea pigs.

T lymphocytes purified from lymph nodes and spleens of chancre-immune, inbred strain 2 guinea pigs, when infused into syngeneic guinea pigs, conferred protection against challenge with Treponema pallidum subsp. pallidum Nichols. No protection was conferred by similar injections of cell suspensions from normal guinea pigs or guinea pigs immunized with T. phagedenis biotype Reiter or T. pallidum-free testis supernatants from infected rabbits. Similar results were obtained with homozygous C4D guinea pigs. After several months of infection, 2 of 11 strain 2 and 1 of 8 strain C4D recipients of T. pallidum-immune cells developed an erythematous reaction of short duration at the injection site; 2 of these recipients were positive for T. pallidum. Throughout the experimental period the humoral response to treponemal antigens was substantially lower in the adoptively immune guinea pigs than in various unprotected control groups. Passive immunity to infection with T. pallidum, however, seems to be dose related, since asymptomatic infection persisted for as long as 3 months after challenge in strain 2 guinea pigs transfused with 10(8) T. pallidum-immune lymphocytes, but not in C4D recipients of twice as many immune cells.     

Chlamydial pneumonitis induced in newborn guinea pigs.

One- to three-day-old guinea pigs were inoculated intranasally with the chlamydial agent of guinea pig inclusion conjunctivitis. Physical signs of infection included a marked increase in respiration rate on days 5 to 10 of infection and radiographic evidence of pneumonia on day 6. When animals were killed at various times after infection and lung tissue was examined by histopathology, evidence of pneumonia was found beginning on day 4 and lasting as long as day 12, with maximal pathological changes on days 6 to 8. The pneumonia was generally unilateral and consisted of an acute inflammatory component in the bronchioles with granulocytes in both the lumen and the wall of the bronchioles and an interstitial and intra-alveolar mononuclear infiltrate in the parenchyma of the lung. Chlamydial antigen was detected in the bronchial epithelial cells by immunoperoxidase staining, and the guinea pig inclusion conjunctivitis organism was isolated from lung tissue on days 6 to 9. No other significant bacteria were isolated from lung tissue or seen on gram stains of lung sections. Both immunoglobulin M and immunoglobulin G serum antibodies to the guinea pig inclusion conjunctivitis agent were detected as early as day 8 and reached peak levels on day 12. The infection was apparently self-limiting. This model presents the opportunity to investigate pathophysiological and immunological aspects of chlamydial respiratory infections in a neonatal animal.