Interstitial cell tumors in a young adult New Zealand white rabbit

One case of interstitial cell tumors in the testicles of a New Zealand White rabbit was reported. The rabbit was 8-10 months old and had bilateral testicular lesions. There was no enlargement of either testicle and the lesions were first seen on the cut surface. Light and electron microscopy revealed that the cellular morphology resembled the features observed for this tumor in rats, dogs, and a few other domestic animals in which reports are available.     

Endosulfan splenic pathology and amelioration by vitamin C in New Zealand rabbit

Endosulfan, a chlorinated hydrocarbon insecticide/acaricide, is a member of a cyclodiene sub-group of poisons to a wide variety of insects and mites. It is also toxic to humans and animals, but there is limited knowledge about endosulfan-related splenic and overall immunotoxicity. The aim of this study was to review pathological findings of endosulfan toxicity in the spleen and to examine potential protective effects of the anti-oxidant Vitamin C (Vit C). Here, after 6-week exposures, the spleens of New Zealand White rabbits were examined grossly and histopathologically and tissue caspase-3 activity was assessed immunohistochemically. Rabbits in four groups were used: Group END were given by oral gavage a sub-lethal dose of endosulfan (1?mg/kg) in corn oil daily for 6 weeks; Group END?+?C received the same dose of endosulfan daily and Vit C (20?mg/kg) every other day by gavage during this period; Group Vit C received oral corn oil daily and 20?mg/kg Vit C every other day; and Group OIL received corn oil daily for 6 weeks. Analyses of the tissues collected 1 week after the final dosing revealed lymphocyte depletion and necrosis in spleens of the hosts that received the pesticide (END only and END?+?C); hemorrhage and slight neutrophilic infiltration was also noted. Caspase-3 immunoreactivity was marked in lymphocytes in all spleens of rabbits in both END groups. Overall, these toxicities were mitigated by Vit C co-treatment; in END?+?C hosts, markedly decreased depletion of lymphocytes, inflammation and caspase-3 immunoreactivity were observed. However, even with mitigation, the level of toxicity present was still greater than any seen in the spleens of hosts that received OIL or Vit C alone. These results revealed endosulfan could cause toxicity in the rabbit spleen, characterized by depletion of lymphocytes, inflammation, necrosis and hemorrhage, and that this toxicity could begin to be mitigated by Vit C co-treatment.     

Sebaceous adenocarcinoma of the external auditory canal in a New Zealand white rabbit

A rare sebaceous gland carcinoma of the external auditory canal in a rabbit is described. The tumour was characterized histologically by foci and cords of markedly pleomorphic cells with abundant cytoplasm and variable numbers of vacuoles. A single pulmonary mass had similar histological characteristics. This is the first such tumour reported in a rabbit.     

Secondary palatal development in the New Zealand white rabbit: A scanning electron microscopic study

Examination of surface topography in prefusion stages of secondary palatal development in rabbit embryos reveals a sequence of alterations in the surface cells of the epithelium along the medial margins of the palatal processes. A progressive increase in cellular protrusions resembling lamellipodia and filopodia, as well as cellular necrosis, is observed in those areas that undergo fusion. The changes precede fusion and are restricted to fusion sites. Prior to and at the time of epithelial contact between palatal processes, many long slender cellular protrusions are seen bridging the gap between the approximating tissues. The localization of the epithelial alterations and the appearance of similar cellular morphology in other embryonic epithelial fusion events strongly suggest: either an active role of the epithelial cells in the fusion of the secondary palate, or some common fundamental biochemical events that may facilitate or are responsible for the initial adhesion of such tissues.     

Tubular antigen-associated renal disease in New Zealand white rabbits.

Rabbits immunized with autologous renal tubular antigen (Fx1A) developed tubulointerstitial nephritis whereas sheep anti-Fx1A antibody administered i.v. produced glomerulonephritis (GN). This lesion showed heavy granular glomerular deposition of immunoglobulin and subepithelial electron dense deposits, early proteinuria, leucocyte independence and a temporal pattern of quantitated glomerular antibody binding distinct from that reported to occur in passive Heymann's nephritis in rats. Isoelectric focusing followed by immunoblotting of deoxycholate-soluble Fx1A antigens with the heterologous and autologous antibodies, indicated species differences in epitope recognition which could account for dissociation between the two models.     

Detection of acute smoke-induced airway injury in a New Zealand white rabbit model using optical coherence tomography

Optical coherence tomography (OCT) is a micron scale high-resolution optical technology that can provide real-time in vivo images noninvasively. The ability to detect airway mucosal and submucosal injury rapidly will be valuable for a range of pulmonary applications including assessment of acute inhalation smoke and burn injury. OCT has the potential ability to monitor the progression of airway injury changes including edema, hyperemia, and swelling, which are critical clinical components of smoke-inhalation injury. New Zealand white male rabbits exposed to cold smoke from standardized unbleached burned cotton administered during ventilation were monitored for 6 h using a 1.8-mm diameter flexible fiberoptic longitudinal probe that was inserted through the endotracheal tube. The thickness of the epithelial, mucosal, and submucosal layers of the rabbit trachea to the tracheal cartilage was measured using a prototype superluminescent diode OCT system we constructed. OCT was able to detect significant smoke-injury-induced increases in the thickness of the tracheal walls of the rabbit beginning very shortly after smoke administration. Airway wall thickness increased to an average of 120% (+/-33%) of baseline values by 5 h following exposure. OCT is capable of providing real-time, noninvasive images of airway injury changes following smoke exposure. These studies suggest that OCT may have the ability to provide information on potential early indicators of impending smoke-inhalation-induced airway compromise.     

骨膜联合同种异体骨治疗兔骨缺损模型的实验研究

目的　通过实验动物研究观察骨膜联合同种异体骨治疗骨缺损的效果,探讨其可行性及修复机制。  方法　以新西兰大白兔为研究对象,分为3组,即实验组、对照组和空白组。通过X线、HE染色及荧光定量PCR方法,检测骨膜联合同种异体骨修复骨缺损的效果及其可能机制。  结果　X线检查显示实验组与对照组骨缺损处均已修复,空白组骨缺损处未修复;HE染色结果显示实验组新生骨小梁排列良好,仍有少量异体骨残留,对照组新生骨小梁排列整齐,空白组未见明显新生骨小梁;荧光定量PCR结果显示,术后实验组Spp-1、BMP-2基因表达高于对照组(P<0.05),ColⅠα1基因表达低于对照组(P<0.05)。  结论　骨膜联合同种异体骨能够有效地促进骨缺损的修复。     

Abnormalities of third-order suppressor T cells in old (New Zealand black x New Zealand white) F1 mice.

The suppressor T cell (Ts) function of old NZW, NZB, C57BL/6 and (NZB X NZW) F1 [B/W)F1), mice to the 2,4-dinitro-1-fluorobenzene (DNFB) hapten was studied. Intravenous administration of dinitrophenyl (DNP) coupled syngeneic lymphoid cells (which normally induce DNP specific suppression) did not result in suppression of DNFB-specific contact hypersensitivity (CS) responses in old NZB or (B/W) F1 mice. Nevertheless, when spleen cells from these old mice were injected into young mice (either (B/W)F1 or A/Sn), strong suppression of the induction phase of CS responses was observed. In addition, effector phase suppressor activity was also observed when splenic cells from tolerized old (B/W) F1 donors were transferred into young (B/W)F1 mice during the effector phase of the CS response. In both cases, the significant cells in the transfer were I-J+ T cells. Thus, the old mice retained functional Ts1 and Ts2 suppressor cells. However, the suppressive activity of the old mice could be reconstituted with spleen cells from primed young mice, suggesting that they have a defect in the Ts3 subset. This was further supported by the finding that the significant cells from the primed young mice were I-J positive and cyclophosphamide-sensitive.     

Atherosclerosis induced by diabetogenic diet in New Zealand white rabbits

Atherosclerosis induced by diabetogenic diet in New Zealand white rabbits     

新西兰大白兔脑静脉系统解剖

目的探讨新西兰大白兔脑静脉系统解剖。方法新西兰大白兔20只,采用数字减影血管造影(DSA)和乳胶灌注方法,通过新西兰大白兔股动脉将微导管导入颈内动脉近端造影及经上腔静脉行乳胶灌注,分析新西兰大白兔脑静脉系统解剖。结果新西兰大白兔具有与人类相似的脑静脉解剖。结论新西兰大白兔脑静脉系统与人类相似,对脑静脉及静脉窦动物模型的制作具有重要指导意义。     

An ultrastructural study of the glomerular slit diaphragm in New Zealand black/white mice.

Glomerular epithelial slit alterations and their relation to proteinuria have not been studied in detail in New Zealand Black/White (NZB/W) mice. The kidneys of proteinuric and nonproteinuric female NZB/W mice and normal Swiss albino mice were perfusion-fixed with tannic acid-glutaraldehyde and studied by light and electron microscopy. Semiquantitative studies were performed on full montages of glomeruli enlarged 10,000 times. Fine structural alterations of the epithelial slits, with emphasis on the slit diaphragm, were studied on semiserial thin sections. Proteinuric NZB/W mice with features of membraneous nephropathy exhibited: (1) wedging of electron-dense deposits below the slit diaphragm, (2) enlargement and distortion of interpedicel spaces, (3) displacement, folding, and stacking of slit diaphragms, (4) formation of occluding junctional complexes in residual slits, and (5) variable loss of foot processes. Similar alterations were not observed in controls or nonproteinuric NZB/W mice, including animals having complexes inglomerular mesangia but not in epithlialslits. These studies show that in NZB/W mice, abnormal protein excretion is associated with structural modification of the slit pore and suggest a role for such a component in the process of protein ex     

Changes in electrical properties of rat myometrium during gestation and following hormonal treatments.

1. The membrane properties of the rat myometrium, during gestation and following ovarian hormone treatment, have been investigated with the micro-electrode technique. 2. Spontaneously generated bursts of electrical activity alternating with silent periods were recorded from non-pregnant, pregnant and post-partum myometria. The membrane potential was highest during the middle stage of gestation, but the spike amplitude within a burst was not uniform. In the final stage of gestation and during parturition, the membrane potential was low and the spikes within a burst were of low frequency and uniform amplitude. 3. During parturition and post-partum, a gradual depolarization of the membrane, accompanied by an increase in membrane resistance, occurred before the generation of a burst. 4. Excitability of the membrane fluctuated from a peak just before the generation of a burst to a low after the cessation of a burst. 5. Displacement of the membrane potential by electrical current or by lowering the temperature modified the slope spontaneous depolarization, but the fluctuations of excitability persisted. The Q10 value for the frequency of spontaneous bursts, measured between 36 and 30 degrees C, was 3-8. 6. Hyperpolarization of the membrane increased the maximum rate of rise of the spike, but beyond -70 mV, the rate of rise was reduced. Half-inactivation of spike generation of spike generation occurred at a membrane potential less negative than the interburst potential, indicating that the current carrying system was not fully activated during parturition. 7. In both normal and spayed rats, oestradiol hyperpolarized the membrane and the burst of spikes was generated hyperpolarized the membrane and the burst of spikes was generated on a sustained depolarization. Progesterone slightly hyperpolarized the membrane and burst discharges occurred without a sustained depolarization. Simultaneous treatment with progesterone and oestradiol produced a plateau potential of long duration during burst discharges. 8. The thickness of the muscle layer, length constant of the tissue and time constant of the membrane were measured during gestation and from spayed rats under various hormonal conditions. The length constant of the tissue was increased by oestradiol and was further increased by simultaneous treatment withoestradiol and progesterone. The increase in tissue thickness appeared to have the most marked influence on the length constant. 9. The resting and active membrane properties of the progresterone treated myometrium were similar to those observed during the middle stages of gestation. The oestradiol-treated myometrium did not resemble that during the last stages of gestation and parturition, which was simulated by combination of the two hormones, oestradiol preceding progesterone.     

Antiatherosclerotic effects of antioxidants are lesion-specific when evaluated in hypercholesterolemic New Zealand white rabbits.

Oxidative modification of LDL may represent an initiating event in the formation of monocyte-macrophage foam cells, a major cell present in fatty streaks and atherosclerotic fibrous plaques. Therefore, we studied the effect of such antioxidants as probucol (500 mg/kg) and vitamins E and C (500 mg/kg each) on the regression of induced iliac-femoral lesions and progression of naturally occurring thoracic aortic fatty streak lesions in hypercholesterolemic New Zealand White rabbits. Following an initial 9-week lesion induction phase, both therapies were evaluated for 8 weeks. Probucol lowered plasma cholesterol 47% while vitamins E and C had no effect on plasma cholesterol. Probucol decreased the cholesteryl ester (CE) content of the thoracic aorta by 31% without changing the thoracic aortic lesion coverage. Vitamins E and C decreased thoracic aortic CE content by 40% and lesion coverage by 46%. Neither probucol nor vitamins E and C altered the CE content, lesion size, or macrophage/lesion ratio of the iliac-femoral artery. Thus, we conclude that the effects of antioxidants are specific to the stage of atherosclerotic lesion development. Antioxidant therapy alters the progression and cholesteryl ester enrichment of diet-induced thoracic aortic fatty streaks but has no effect on the progression and/or regression of more complicated injury-induced iliac-femoral lesions.     

Pathogenesis and pathology of respiratory tularaemia in the rabbit.

The development of pathological lesions in the organs of rabbits was examined at intervals from 1 h to 4 days after aerosol infection with Francisella tularensis. The earliest change, accumulation of polymorphonuclear leucocytes (PMN) in ulmonary alveolar ducts, occurred at 19 h. From the 2nd day multiple foci of necrosis and PMN infiltration were present in large airways and alveoli throughout the lungs and progressively increased in size. Pulmonary arteritis was a prominent feature of the infection. Areas of necrosis were present in the nasal mucosa, pharynz and trachea, and pyogranolomatous lesions consistently developed in the liver, spleen, and lymph nodes.