Responses to conspecifics' urine by the degu (Octodon degus)

In nature the degu has been observed to deposit and to investigate scents. This study employed a captive group of these animals to investigate their responses to conspecific urinary marks in a neutral arena. Both sex classes served as subjects. They were presented with urine obtained from males, from females and a saline control. The females were found to be more active in responding. On the basis of sniffing frequency, they exhibited greater discriminative abilities than did the males. The urine from female donors was sniffed more frequently by all subjects. The frequency of approaching a mark and the time spent in the vicinity of a stimulus are interpreted as being investigatory responses. It seems that the marks deposited by females have a greater salience and that females are more sensitive to olfactory stimuli.     

Ultrastructure of well-differentiated adenocarcinomas of the lung with special reference to bronchioloalveolar carcinoma

The cytologic phenotypes of 20 well-differentiated pulmonary adenocarcinomas were determined by electron microscopy. On examination of more than 100 cells in each case, the tumors were classified according to the predominant cell types. Nine cases (45%) were of mucous cell type, further divided into 7 cases of bronchial surface epithelial cell type, 1 case of bronchial gland cell type, and 1 case of metaplastic bronchiolar goblet cell type. The remainder included 5 cases (25%) of Clara cell type, 2 cases (10%) of type II cell type, and 4 cases (20%) of mixed cell type. The predominant histologic pattern by light microscopy was "typically" bronchioloalveolar (Manning et al.'s type 1) in the metaplastic goblet cell tumor and papillary in most Clara cell-type tumors, while it was glandular in bronchial surface and bronchial gland cell types, although variable in type II cell or mixed cell type. Therefore, bronchioloalveolar carcinomas, when histologically defined inclusive of papillary tumors, present cytologic phenotypes also related to the bronchioloalveolar epithelium, i.e., metaplastic goblet or Clara or type II cell subtypes, which is in accordance with some previous reports. These tumors could be distinguished from the other (glandular) adenocarcinomas that show primarily bronchial mucous cell differentiation.     

Ultrastructure of the turtle spermatozoon

The turtle spermatozoon is vermiform in shape with a narrow pointed head that is curved. In general, the turtle sperm contains a typical head, midpiece and tail, similar in morphology to that of birds, amphibians and other reptiles. However, several structures are unique. These unusual features include (1) a perforatorial cap over the proximal end of the nucleus, which contains 2–3 rods that are contiguous with intranuclear tubules; (2) a connecting collar of dense material that surrounds the base of the nucleus; (3) a distal centriole containing central microtubules that extend its entire length and having outer triplicate microtubules that open toward the central cavity of the centriole; and (4) unusual spherical mitochondria containing 7–8 outer laminated membranes.     

Lymphoid cells in the harderian gland of the rodent Octodon degus

The Harderian gland of the degu (Octodon degus) is composed of tubulo-alveolar secretory units that share most of morphological features found in the Harderian glands of other rodents. However, a peculiar characteristic observed in the glands of female degus is the existence of lymphoid cell clusters within the connective tissue surrounding the secretory adenomeres. Lymphocytes and lymphoblasts are found associated with blood vessels and especially with nerve bundles in the medullary region of the gland. Occasionally, macrophages and plasma cells are also observed. Although the Golgi apparatus appears well developed, the ultrastructural characteristics of most of these lymphoid elements correspond to those of inactive lymphocytes. Unmyelinated fibers containing clear and dense-core vesicles are found closely related to lymphocytes. On some occasions, lymphocytes present extensive areas of apposition with structures resembling intercellular junctions. The analogy of the lymphoid clusters reported in this study with those described in the avian Harderian gland is discussed.© Willey-Liss, Inc.     

Ultrastructure of the spleens in childhood ITP with special reference to the foamy cells

We examined the spleens from four patients with childhood ITP. Numerous foamy cells were investigated in two cases, moderate number in one case, and a few in one case. PAP method using anti-human platelet antibody demonstrated the platelet antigen in the cytoplasms of these foamy cells, which were granular or reticular. Electron microscopically, many platelets in various stages of intracellular digestion from intact-appearing forms to myelin-like materials, were disclosed. Enzyme cytochemical electron microscopy revealed localization of acid phosphatase activity around the degrading platelets and vacuolated inclusions, but rarely in the myelin-like materials. We suggest that the mechanism of formation of the foamy cells in ITP is as follows; macrophages phagocytize many platelets, exhaust their lysosomal enzyme, and can not digest the engulfed platelets completely. Thus the partially degraded platelets remain as myelin-like materials in the cytoplasm of macrophages, which have foamy appearance in light microscopy.     

Morphogenesis of the acrosome during the final steps of rat spermiogenesis with special reference to tubulobulbar complexes

We report the ultrastructural changes in acrosome morphology during the final steps of rat spermiogenesis, focusing on the relationship between the acrosome morphogenesis and the tubulobulbar complexes (TBC) development. During steps 18–19, the electron‐lucent area in the dorsal cortex of the anterior acrosome gradually diminished, and finally, the acrosome became condensed and reduced its volume. Simultaneously with this tightening up of the acrosome, TBC developed from the head portion of late spermatids, protruding into the surrounding Sertoli cells. To investigate the incorporation of acrosomal contents into TBC, step 19 spermatids were stained by periodic acid‐Schiff (PAS) reaction and by using the anti‐acrosomal monoclonal antibody mMN7. Both PAS‐reactivity and the mMN7‐immunoreactivity were found in the TBC, as well as in the acrosome. In addition, the acrosome projected into the TBC‐like structure, and materials of a density similar to that of the acrosome were observed in the core of the TBC. These results suggest that the TBC eliminate excess acrosomal contents prior to spermiation. Anat Rec 256:195–201, 1999. © 1999 Wiley‐Liss, Inc.     

Lymphoid cells in the harderian gland of the rodent Octodon degus.

The Harderian gland of the degu (Octodon degus) is composed of tubulo-alveolar secretory units that share most of morphological features found in the Harderian glands of other rodents. However, a peculiar characteristic observed in the glands of female degus is the existence of lymphoid cell clusters within the connective tissue surrounding the secretory adenomeres. Lymphocytes and lymphoblasts are found associated with blood vessels and especially with nerve bundles in the medullary region of the gland. Occasionally, macrophages and plasma cells are also observed. Although the Golgi apparatus appears well developed, the ultrastructural characteristics of most of these lymphoid elements correspond to those of inactive lymphocytes. Unmyelinated fibers containing clear and dense-core vesicles are found closely related to lymphocytes. On some occasions, lymphocytes present extensive areas of apposition with structures resembling intercellular junctions. The analogy of the lymphoid clusters reported in this study with those described in the avian Harderian gland is discussed.     

Morphogenesis of the acrosome during the final steps of rat spermiogenesis with special reference to tubulobulbar complexes.

We report the ultrastructural changes in acrosome morphology during the final steps of rat spermiogenesis, focusing on the relationship between the acrosome morphogenesis and the tubulobulbar complexes (TBC) development. During steps 18-19, the electron-lucent area in the dorsal cortex of the anterior acrosome gradually diminished, and finally, the acrosome became condensed and reduced its volume. Simultaneously with this tightening up of the acrosome, TBC developed from the head portion of late spermatids, protruding into the surrounding Sertoli cells. To investigate the incorporation of acrosomal contents into TBC, step 19 spermatids were stained by periodic acid-Schiff (PAS) reaction and by using the anti-acrosomal monoclonal antibody mMN7. Both PAS-reactivity and the mMN7-immunoreactivity were found in the TBC, as well as in the acrosome. In addition, the acrosome projected into the TBC-like structure, and materials of a density similar to that of the acrosome were observed in the core of the TBC. These results suggest that the TBC eliminate excess acrosomal contents prior to spermiation.     

The lack of recognition of lactating females by infant Octodon degus

A series of tests were conducted to determine whether infant degus (Octodon degus) will (a) show sensitivity to maternal olfactory cues and/or (b) discriminate between a novel adult lactating female and their mother. The pups showed no preferences when exposed to an array of different olfactory stimuli but did spend significantly more time in proximity with the novel lactating female than with their mothers. It is hypothesized that the communal rearing systems which are apparently characteristic of degus in the wild, coupled with the novelty of the lactating female, may account for these results.     

多疣壁虎精子超微结构

目的:研究多疣壁虎精子超微结构,探讨爬行类精子进化规律.方法:用光镜及透射电镜观察多疣壁虎的精子.结果:多疣壁虎精子总长度约65～75 μm,头部弯曲长约27～30μm,尾部约 40～47 μm.用透射电镜观察多疣壁虎精于超微结构,可见其精子具有以下特点:顶体复合体由顶体帽、顶体下问隙、穿孔器、中央管、顶体下核帽5个部分组成;中段的轴丝复合体与线粒体鞘之间具有微管鞘(microtubule sheath)结构,线粒体鞘向后延伸包围主段,形成终环后隐窝结构;主段具有厚的圆筒状纤维鞘.结论:多疣壁虎精子超微结构比较研究显示爬行类精子具有种的特异性,提示了爬行类可能为多源起源.     

Ultrastructure of the ovarian germ cells in the quail embryos, with special reference to the oocytes

Developing germ cells from oogonia to oocyte stages in embryonic quail ovaries were observed ultrastructurally. In contrast with those of chicks, quail oocytes showed some conspicuous structures. Typical feature of the Balbiani body, which was constructed by eccentrical concentration of whole organelles, was observed through the oocyte stage, although loose aggregations of organelles were found even at the oogonial stage. Such striking feature of Balbiani body was not observed as yet in any animal species. Golgi apparatus, which occupied the center of a Balbiani body, was often found attaching with the nuclear membrane. This finding suggests that the Balbiani body play some role for the oocyte maturation. Upon the nuclear membrane of oocytes, a great number of electron dense structures were found. They were thought to be a kind of nuclear pore complexes. Such abundance of the nuclear pore complexes was another structural characteristic of quail oocytes. They increased in number according to the progress of embryonic development, although small numbers were also seen even at the oogonial stage.     

Ultrastructure of ultraviolet radiation-induced hairless mouse skin carcinogenesis, with special reference to the epidermal-dermal junction

The ultrastructure of ultraviolet (UV)-induced skin pathology was studied in mice to complement previously reported gross and light microscopic findings, and to assess further the usefulness of the animal model for study of sunlight associated epidermal tumours in man. Hairless albino (HRA/Skh-1) mice were exposed to a minimal erythemal dose from a filtered light source emitting both UVA and UVB, approximating solar emission. Samples of normal and hyperplastic skin, pedunculated papillomas, carcinomas in situ and invasive squamous cell carcinomas were processed for transmission electron microscopy once their identity was confirmed by light microscopic examination. Keratinocyte pleomorphism became more marked and cell to cell contact diminished as malignancy developed. For papillomas, carcinomas in situ and invasive squamous cell carcinomas, there was a progressive disruption of the epidermal junction which became marked upon frank invasion. Most of the differences between the various categories of pathological change, therefore, were not absolute but rather of degree, supporting the notion that invasive squamous cell carcinoma represents an end stage for malignancy which may arise de novo, directly from hyperplastic skin, or proceed from other tumour types. The similarity in structure of the mouse tumours to comparable tumours in man supports the usefulness of the animal model and suggests that the results have implications for sunlight associated tumours in man.     

Early social deprivation alters monoaminergic afferents in the orbital prefrontal cortex of Octodon degus

The influence of early parental deprivation on the development of tyrosine hydroxylase- and 5-hydroxytryptamine-immunoreactive fiber innervation of subregions of the orbital prefrontal cortex (ventrolateral orbital, lateral orbital and agranular insular cortex) was quantitatively investigated in the precocious lagomorph Octodon degus. Forty-five-day-old degus from two groups were compared: 1) degus which were repeatedly separated from their parents during the first three postnatal weeks, and after weaning they were reared in social isolation; and 2) degus which were reared undisturbed in their families. Compared with the normal control animals the ventrolateral orbital prefrontal cortex and agranular insular cortex of the deprived animals displayed significantly increased density of tyrosine hydroxylase-immunoreactive fibers (up to 172% in the ventrolateral orbital prefrontal cortex and up to 143% in the agranular insular cortex). The lateral orbital prefrontal cortex showed increased 5-hydroxytryptamine-positive fiber densities (up to 118%).This altered balance between the serotonergic and dopaminergic cortical innervation in the orbital prefrontal cortex may reflect an anatomical and functional adaptation, which may be triggered by an altered activity of these transmitter systems during the phases of parental separation and social isolation.     

Ultrastructure of kidney from three patients with HBeAg-associated nephropathy with special reference to virus-like particles in the glomerular tufts

The biopsied kidneys from three patients with hepatitis Be antigen (HBeAg)-associated nephropathy were observed by light microscopy, immunohistochemistry and electron microscopy. By an indirect technique utilizing horseradish peroxidase-conjugated antisera, HBeAg was found to be deposited in a diffuse granular fashion along the glomerular capillary wall. No deposition of hepatitis Bs or hepatitis Bc antigen was detected. The three cases were diagnosed as HBeAg-associated nephropathy. Ultrastructurally, there were finely granular electron-dense deposits in the subendothelial area, basement membrane, mesangial area and subepithelial area of the glomerular tufts. In all three cases, virus-like particles between 30 and 70 nm in diameter were also found in such areas of the glomerular tufts, and rarely in the glomerular capillary lumen and space of Bowman. They occasionally formed clusters in the phagosomes of mesangial cells. In addition, tubulo-reticular structures were noted in the cytoplasm of endothelial cells in the glomerular capillaries. The presence of HBeAg both in the serum and in the kidney and of virus-like particles in the glomerular tufts suggests that HBeAg is causally related to the development of HBeAg-associated nephropathy.     

Influence of parental deprivation on the behavioral development in Octodon degus: modulation by maternal vocalizations

Repeated separation from the family during very early stages of life is a stressful emotional experience which induces a variety of neuronal and synaptic changes in limbic cortical areas that may be related to behavioral alterations. First, we investigated whether repeated parental separation and handling, without separation from the family, leads to altered spontaneous exploratory behavior in a novel environment (open field test) in 8-day-old Octodon degus. Second, we tested whether the parentally deprived and handled animals display different stimulus-evoked exploratory behaviors in a modified open field version, in which a positive emotional stimulus, the maternal call, was presented. In the open field test a significant influence of previous emotional experience was found for the parameters of running, rearing, and vocalization. Parentally deprived degus displayed increased horizontal (running) and vertical (rearing) motoric activities, but decreased vocalization, compared to normal and handled controls. The presentation of maternal vocalizations significantly modified running, vocalization, and grooming activities, which in the case of running activity was dependent on previous emotional experience. Both deprivation-induced locomotor hyperactivity together with the reduced behavioral response towards a familiar acoustic emotional signal are similar to behavioral disturbances observed in human attachment disorders.     

Ultrastructure of early phase hepatic metastasis of human colon carcinoma cells with special reference to desmosomal junctions with hepatocytes

To demonstrate ultrastructural events in the early phase of hepatic metastasis of human colon carcinoma, we intrasplenically injected a highly metastasizable, human colon carcinoma cell line LM-H3 (1 x 10(6) cells) into nude mice, and electron microscopically investigated the hepatic metastasis. At 24 h, tumor cells adhered to the endothelial wall of terminal portal venules and periportal sinusoids. At 48-72 h, after extravasation, they deeply invaded the hepatic cell plate and the interstitial tissue of the portal tract, in which they underwent proliferation and made the metastatic foci. Tumor cells were linked with each other or with surrounding hepatocytes by desmosomes. Desmosomes were maintained during the mitosis. When invading tumor cells were exposed to the bile canaliculi, they generated microvilli on the surface. Microvilli were also formed at the luminal surface of intracytoplasmic inclusions. In the interstitial tissue of the portal tract, tumor cells were closely associated with fibroblasts. However, no junctional specializations were seen between them. The present study demonstrated that human colon carcinoma cell line LM-H3 formed desmosomes with hepatocytes soon after invasion of the hepatic cell plate, suggesting the regulatory role of an interaction with hepatocytes in the growth of metastatic foci within the liver parenchyma.     

Brief periods of positive peer interactions mitigate the effects of total social isolation in young Octodon degus

We investigated whether positive daily peer‐interactions counteract the effects of isolation in Octodon degus. Twenty‐five‐day‐old degus were either isolated (ISO), socially housed (SOCIAL), or isolated and allowed 1‐hr daily peer interaction (PARTIAL‐ISO). The animals were observed over 4 weeks. Just prior to isolation and after 2 weeks of individual housing, the subjects were assessed for response to pleasant stimuli via a sucrose preference test and to fearful situations in open field and startle tests. Two weeks after the previous tests, the subjects were retested as above and observed in novelty and sociability tests. Only the ISO group showed significant alterations in sensitivity to reward and increased risk‐taking behavior in fearful situations. The ISO group consumed more sucrose, spent less time freezing in the startle test and exhibited increased exploration in open field and novelty tests compared to PARTIAL‐ISO and SOCIAL groups. In the sociability test, the SOCIAL group vocalized more than the other two groups during encounters with an unfamiliar degus. Our findings suggest that (i) chronic isolation induces alteration of hedonic, emotional and social profiles, with a maturational delay in fear‐related responses; (ii) friendly interaction attenuates most behavioral changes induced by total social isolation. However, the positive effects of daily social interactions did not fully counteract deficits in social vocalizations. Our study represents one of the few available studies focused not only on the consequences of negative life events in this species, but also the protective role of relatively short periods of positive social activity on subsequent emotional development. © 2010 Wiley Periodicals, Inc. Dev Psychobiol 53:280–290, 2011.     

Contact-promoting behavior,social development,and relationship with parents in sibling juvenile degus (Octodon Degus)

This study describes infant socialization in captive parent-young units of the caviomorph rodent Octodon degus. Types of parent-young contact (huddling or squatting) and social interaction (body nosing and accompanying behaviors) are described and their ontogenetic trends examined between postnatal Days 1 and 46. Fathers spent less time than mothers in contact with the young. Mother-young contact decreased postnatally, whereas the amounts of mother-young and father-young social interaction, measured in terms of body-nosing exchanges, showed a continuous increase postnatally; sibling interactions also showed a continuous increase. Father-young interactions tended to be dominated by the father. Young reared with the father cohabiting huddled less with their mother, and engaged in less body-nosing, than young reared in the father's absence. Observations suggested that paternal control of the young may curb juvenile interactions. Young observed without their parents in an unfamiliar enclosure did not groom or “play” as in their home cage with parents present, but engaged in relatively more vocalizing, neck-nosing and forepaw-clasping.