The effect of growth media and physical treatments on the adhesion properties of canine probiotics

AIMS

The manufacturing processes have been reported to influence the properties of probiotics with potential impact on health properties. The aim was to investigate the effect of different growth media and inactivation methods on the properties of canine-originated probiotic bacteria alone and in combination mixture.

METHODS AND RESULTS

Three established dog probiotics, Lactobacillus fermentum VET9A, Lactobacillus plantarum VET14A and Lactobacillus rhamnosus VET16A, and their combination mixture were evaluated for their adhesion to dog mucus. The effect of different growth media, one reflecting laboratory and the other manufacturing conditions, and inactivation methods (95°C, 80°C and UV irradiation) on the mucus adhesion of the probiotic strains was characterized. Evaluation of dog probiotics was supported by cell visualization using transmission electron microscopy (TEM). Higher adhesion percentage was reported for probiotic strains growing in laboratory rather than in manufacturing conditions (P < 0.05). Inactivation by heat (95°C, 80°C) decreased the adhesion properties when strains were cultivated in soy-based growth media compared with those grown in MRS broth (P < 0.05). TEM observations uncovered differences in cell-surface components in nonviable forms of probiotic strains as compared with their viable forms.

CONCLUSIONS

Manufacturing process conditions such as growth media and pretreatment methods may significantly affect the adhesive ability of the tested strains.

SIGNIFICANCE AND IMPACT OF THE STUDY

Growth conditions, growth media, pretreatment methods and different probiotic combinations should be carefully considered for quality control of existing probiotics and for identification of new probiotics for dogs. These may also have an impact on health benefits for the host.

Adhesion and proliferation of human fibroblasts on sol-gel coated titania

The objective of this study was to evaluate growth and attachment of human gingival fibroblasts on nonresorbable sol-gel-derived nanoporous titania (TiO2) coated discs and noncoated commercially pure titania (cpTi) discs in vitro. The strength of attachment was evaluated using serial trypsinization. The number of cells detached from TiO2-substrates was 30% +/- 3%, whereas those detached from the cpTi was 58% +/- 4% indicating a stronger cell attachment on the coated surfaces. In scanning electron microscopy (SEM) images fewer cells, with more rounded shape, were seen with cpTi than with TiO2 after the detachment assay. Fibroblasts grew more efficiently on TiO2 than on cpTi substrates, showing significantly higher cell activities at all times. In transmission electron microscopy (TEM), a continuous layer of two to three cells thick covered the coated and noncoated discs after 7 days of culture. The plasma membrane of cells in contact with the coating was in close opposition and the cytoplasm was ultrastructurally similar to the cells grown on noncoated discs with well-preserved organelles. In conclusion, we demonstrated that the sol-gel-derived TiO2 coatings can facilitate cell growth and attachment of human gingival fibroblasts on titanium in vitro. This in vitro study is in line with our previous in vivo observations of improved soft tissue attachment of TiO2 coatings in comparison with cpTi.

Soft tissue attachment on sol-gel-treated titanium implants in vivo

This study was designed to examine the attachment and reactions of soft tissues to sol-gel-derived TiO2 coatings. In the first experiment, TiO2 coated and uncoated titanium cylinders were placed subcutaneously into the backs of rats for 3, 11 and 90 days. Tissue response and implant surfaces were characterized with routine light microscopy and scanning electron microscopic (SEM) analysis. In the second experiment, TiO2-coated and uncoated discs were implanted subcutaneously into the backs of rats for 14 and 21 days. The discs were pulled out from the implantation sites with a mechanical testing device using a constant speed of 5 mm/min. Rupture force was registered, after which the discs were assigned for SEM and transmission electron microscopic (TEM) analysis. All the coated implants showed immediate contact with the surrounding soft tissues without a clear connective tissue capsule. Significantly better soft tissue response was measured for all the coated compared to the uncoated cylinders (p<0.01). Higher rupture forces were measured for all coated discs, although the differences were not statistically significant. An immediate and tight connection between connective tissue fibroblasts and coatings was noticed in TEM analysis. Our study indicates that TiO2 coatings improve soft tissue attachment on a titanium surface.

Morphometric and ultrastructural analysis of stage-specific effects of Sertoli and spermatogenic cells seen after short-term testosterone treatment in young adult rat testes

The effects of testosterone treatment on spermatogenesis in the rat have been investigated by morphometric and structural analysis at the ultrastructural level in stages VII-IX. The aim has been to characterize the changes in Sertoli and spermatogenic cells to elucidate the mechanism of testosterone effects on spermatogenesis and to test the possibilities of developing male contraceptives. In stage VII, the morphometric parameters of volume and surface area in Sertoli cells (see abbreviations below): and the morphometric parameter of volume in the spermatogenic cells such as V(VPG,T), V(VPC,T), V(VrPT,T) and V(VelPT,T) decreased. In stage VIII, the respective values of Sertoli cells, VSN, and VSN/VSC decreased while SSJ increased, and the respective morphometric parameters in the spermatogenic cells, V(VPG,T), V(VPC,T), and V(VrPT,T) increased. In stage IX, in Sertoli cells VSC, VSN, VSN/VSC, and SSJ remained unchanged. In spermatogenic cells V(VPG,T), V(VPC,T), and V(VrPT,T) increased. Further, in all stages, a close apposition of mitochondria and rough endoplasmic reticulum in basolateral cytoplasm of Sertoli cells suggested active protein synthesis. In elongated spermatids in stage IX the microtubular manchette became disorganized. This disorganization and the unexpected shift after testosterone treatment from decrease in several morphometric parameters in stage VIII to increases in stage IX cannot be explained by alterations in testosterone (T), LH, FSH, and their respective receptors. Therefore, still unknown regulatory factors in spermatogenesis are apparently involved in the developmental interactions between Sertoli and spermatogenic cells.

Mechanisms of kainate-induced region-specific neuronal death in immature organotypic hippocampal slice cultures

Excessive activation of excitatory amino acid receptors has been implicated in neuronal death in a number of central nervous system insults. We have here investigated, the time course and mechanisms of kainate (KA)- induced neuronal death in immature organotypic hippocampal slice cultures (OHCs) using Fluoro-Jade B (FJB) staining as a marker of cell death, and immunoblotting, immunocytochemistry, and electron microscopy as methods to clarify the mechanisms. After 6 KA treatment (5 microM), no significant neuronal death was detected in any hippocampal subregion, whereas the treatment of 12, 24, and 48 h resulted in neuronal death in the CA3 regions, but not in CA1. The 48 h resting period in normal medium after KA-treatment did not rescue the cells but further increased the number of dead neurons in CA3 as compared to the corresponding acute phase. In Western blotting, the expression levels of the active, 17 kDa form of caspase-3, and the 84-85 kDa cleaved fragment of poly(ADP ribose)polymerase (PARP) were not altered from the control levels. Moreover, no active caspase-3 labelled cells were detected in immunocytochemical study 24 h after KA treatment either in the acute or resting groups. Electron microscopy showed non-apoptotic injury in the CA3a/b pyramidal neurons in KA-treated slices. Our results suggest that KA-induced neuronal death in immature OHCs is a strictly region-specific, irreversible, necrotic process.

Effect of Endothelin-1 on Apoptosis, Proliferation, and Protein Synthesis in Cardiomyocytes of Newborn Albino Rats

Five intraperitoneal injections of endothelin-1 (100 microg/kg) to newborn albino rats on days 2-6 of life did not change the number of nuclei expressing PCNA in the left-ventricular myocardium. The number of nucleoli, area and perimeter of cardiomyocytes (isolated by the method of alkaline dissociation) increased. The number of myocyte nuclei in the state of apoptosis (evaluated by the TUNEL method) increased significantly. Presumably, partial loss of cardiomyocytes as a result of apoptosis activation after treatment with endothelin-1 is compensated by increased size and transcription activity of remaining cardiomyocytes.

Expression of Sox9 and type IIA procollagen during ocular development and aging in transgenic Del1 mice with a mutation in the type II collagen gene

PURPOSE

To study the expression and distribution of transcription factor Sox9 and type IIA procollagen in the developing and aging eyes of normal and transgenic Dell mice carrying pro(alpha)1(II) collagen transgenes with a short deletion mutation, which cause ocular abnormalities in this mouse line.

METHODS

The eyes of Del1 mice were studied on embryonic days E14.5, E16.5 and E18.5, and at the ages of 4 and nine months, using their nontransgenic littermates as controls. Sox9 and pro(alpha)1(IIA) collagen were detected by RNase protection assay and immunohistochemistry.

RESULTS

RNase protection assay revealed Sox9 transcripts in the eyes of Del1 and control mice during development and aging. The mRNA for type IIA procollagen had a similar temporal expression pattern. On embryonic days E14.5, E16.5 and E18.5, Sox9 was located by immunohistochemistry in the nuclei and type IIA procollagen in the extracellular space of the developing retina. During growth and aging, the ocular expression of Sox9 mRNA and the immunohistochemical reaction for Sox9 antibody diminished, concomitant with the reduction in type II procollagen mRNA. However, at the age of nine months, levels of Sox9 and type IIA procollagen mRNAs were higher in the degenerating eyes of Del1 and control mice.

CONCLUSIONS

The similarities in the temporo-spatial distribution of Sox9 and type IIA procollagen suggest that this transcription factor is involved in the activation of type II collagen expression in the eye, as has been demonstrated in prechondrogenic mesenchyme and immature cartilage. The increased production of Sox9 and type IIA procollagen in the aging retina and vitreous is analogous to degenerating articular cartilage where attempted tissue repair has also been observed.

Alveolar integrity and ultrastructure in pigs remain undamaged after exposure to sevoflurane

Previous studies have shown that both halothane and isoflurane have adverse but reversible effects on alveolar physiology. The present study was designed to test the hypothesis that also sevoflurane may affect alveolar integrity. Fifteen pigs were randomly selected to receive either thiopentone infusion (control group, n=8) or sevoflurane (n=7) at 4.0% inspiratory concentration (1.5 MAC) in air for 6 h. Tissue samples from the lungs were obtained at the end of the experiment. Both histopathological light microscopy and electron microscopy were used to assess the structural integrity of the alveoli. Pulmonary hemodynamics were comparable in both groups. Light microscopy showed no difference between the groups in the amount of alveolar macrophages, red blood cells or edema. Electron microscopy showed minor changes such as moderate local swelling of alveolar epithelium in both study groups. Alveolar type II cells were ultrastructurally unaltered in both study groups. We conclude that long-term, high concentration exposure to sevoflurane has no detrimental effect on the alveolar integrity in pigs.

Autocrine production and synergistic growth-promoting activity of interleukin-6 and oncostatin M in a new human myeloma cell line TU-1

Human myeloma cell lines are difficult to establish, and they usually originate from patients with extramedullary disease. We describe a new human myeloma cell line, TU-1, which was established from the bone marrow of a patient without extramedullary myeloma. The myeloma cells were initially maintained in a conditioned medium derived from another well-known myeloma cell line U-266. This conditioned medium contained interleukin-6 (IL-6) and oncostatin M (OSM), and possibly other unknown growth factors as well. In 3 months the TU-1 cell line proliferated autonomously and secreted IL-6 and OSM with a synergistic growth response. As we have previously shown the cell line acquired a p53 mutation in vitro, which may be an important factor causing autonomous proliferation. In patients with multiple myeloma OSM is frequently found in the serum and OSM has been associated with serum IL-6 and progressive disease. Our study demonstrates the close relationship of OSM and IL-6 also in vitro.

Contribution of domestic animals to the identification of new genes involved in sex determination

Among farm animals, two species present an intersex condition at a relatively high frequency: pig and goat. Both are known to contain XX sex-reversed individuals which are genetically female but with a true hermaphrodite or male phenotype. It has been clearly demonstrated that the SRY gene is not involved in these phenotypes. Consequently, autosomal or X-linked mutations in the sex-determining pathway may explain these sex-reversed phenotypes. A mutation referred to as "polled" has been characterized in goats by the suppression of horn formation and abnormal sexual differentiation. The Polled Intersex Syndrome locus (PIS) was initially located in the distal region of goat chromosome 1. The homologous human region has been precisely identified as an HSA 3q23 DNA segment containing the Blepharophimosis Ptosis Epicanthus locus (BPES), a syndrome combining Premature Ovarian Failure (POF) and an excess of epidermis of the eyelids. In order to isolate genes involved in pig intersexuality, a similar genetic approach was attempted in pigs using genome scanning of resource families. Genetic analyses suggest that pig intersexuality is controlled multigenically. Parallel to this work, gonads of fetal intersex animals have been studied during development by light and electron microscopy. The development of testicular tissue and reduction of germ cell number by apoptosis, which simultaneously occurs as soon as 50 days post coïtum, also suggests that several separate genes could be involved in pig intersexuality.

Time course of female-to-male sex reversal in 38,XX fetal and postnatal pigs

In an attempt to understand the etiology of intersexuality in pigs, we thoroughly analyzed the gonads of 38,XX (SRY negative) female to male sex-reversed animals at different developmental stages: during fetal life [50 and 70 days postcoitum (dpc)], just after birth [35 days postpartum (dpp)] and during adulthood. For each animal studied, we performed parallel histological and ultrastructural analyses on one gonad and RT-PCR analysis on the other gonad in order to define the expression profiles of sexually regulated genes: SOX9, 3beta-HSD, P450 aromatase, AMH, FOXL2, and Wnt4. Light and electron microscopic examination showed that testicular cords differentiated in XX sex-reversed gonads but were hypoplastic. Although the testicular cords contained gonia at the fetal stages, the germ cells had all died through apoptosis within a few weeks after birth. Ultrastructurally normal Leydig cells also differentiated, but later, and enclosed whorl-like residual bodies. At the fetal stages, three of the six genes studied in the intersex gonads presented, as early as 50 dpc, a modified expression profile corresponding to an elevated expression of SOX9 and the beginning of AMH and P450 aromatase gene transcription. In addition to genes involved in the testicular pathway, the same gonads expressed FOXL2, an ovarian-specific factor. The ovaries of true hermaphrodites were ineffective in ensuring correct folliculogenesis and presented abnormal expression profiles of ovarian specific genes after birth. These results indicate that the genes involved in this pathology act very early during gonadogenesis and affect the ovary-differentiating pathway with variable expressivity from ovarian germ cell depletion through to trans-differentiation into testicular structures.

Structural and regulatory macromolecules in sex differentiation of gonads

The manifestations of sex determination were studied in vivo by detection and localization of structural and regulatory macromolecules (type IV collagen alpha 1, alpha 2, alpha 3, alpha 4, and alpha 5; laminin alpha 5, beta 1, and beta 2; cytokeratins 18 and 19, desmin, vimentin; integrin alpha(6;) anti-Müllerian hormone (AMH); and SOX9 in developing male and female gonads by light and electron microscopy, immunocytochemistry, and protein analysis. The goal has been to find sex-related differences and on this basis to offer new molecules to be tested further for a possible role in sex determination. Specific antibodies for each molecule or for a defined subchain were used to allow tentative correlation with specific genes. Sex-dependent differences in timing and localization were found in laminin alpha 5; collagen, alpha 3, alpha 4, and alpha 5; cytokeratin 19; AMH; and SOX9. On this basis we hypothesize that the transcription factors for the mentioned structural proteins must be directly or indirectly involved in the regulatory chain of gonadal sex differentiation. Especially promising is the finding in the rat that laminin alpha 5 chain disappears from the basement membrane of embryonic testicular cords (Sertoli cells) when AMH secretion by Sertoli cells starts, and that the same chain reappears as the AMH disappears two weeks after birth. Via AMH as an intermediary factor, we now have for the first time a putative cascade of regulatory molecules from SRY, SF1, and SOX9 to a component of a structural protein (laminin alpha 5 chain) which directly participates in the formation of the basement membrane of the testicular cords. J. Exp. Zool. 290:523-528, 2001.

Ultrastructural, morphometric, and hormonal analysis of the effects of testosterone treatment on Leydig cells and other interstitial cells in young adult rats

Early effects of testosterone (T) treatment on the ultrastructure of testicular interstitium were analyzed by morphometry. In T-treated young adult rats the T-LH feed-back loop functioned as expected and the marked increase in peripheral T caused almost complete depletion of peripheral LH. Even though the peripheral LH concentration was almost undetectably low, the Leydig cells maintained regulatory interactions with macrophages, peritubular myoid cells and with the seminiferous epithelium lining the tubular lumina as indicated by the high correlations of morphometric parameters between the Leydig and other cell types. The morphometric alterations in the ultrastructure of Leydig cells suggest that the seminiferous tubules may signal by releasing inhibitory paracrine factors affecting the morphology and function of Leydig cells in T-treated young adult rats. The morphometry of Leydig cells in T-treated young adult rats showed a significant quantifiable reduction in nuclei and organelles involved in steroid synthesis and this analysis also offers a good basis for elucidation of the early effects of testosterone in terms of its contraceptive function as well as of different toxic compounds on reproductive functions.

Overlapping and differential localization of Bmp-2, Bmp-4, Msx-2 and apoptosis in the endocardial cushion and adjacent tissues of the developing mouse heart

The bone morphogenetic proteins BMP-2 and BMP-4 and the homeobox gene MSX-2 are required for normal development of many embryonic tissues. To elucidate their possible roles during the remodeling of the tubular heart into a fully septated four-chambered heart, we have localized the mRNA of Bmp-2, Bmp-4, Msx-2 and apoptotic cells in the developing mouse heart from embryonic day (E)11 to E17. mRNA was localized by in situ hybridization, and apoptotic cells by TUNEL (TDT-mediated dUTP-biotin nick end-labeling) as well as by transmission electron microscopy. By analyzing adjacent serial sections, we demonstrated that the expression of Msx-2 and Bmp-2 strikingly overlapped in the atrioventricular canal myocardium, in the atrioventricular junctional myocardium, and in the maturing myocardium of the atrioventricular valves. Bmp-4 was expressed in the outflow tract myocardium and in the endocardial cushion of the outflow tract ridges from E12 to E14. Msx-2 appeared in the mesenchyme of the atrioventricular endocardial cushion from E11 to E14, while Bmp-2 and Bmp-4 were detected between E11 and E14. Apoptotic cells were also detected in the mesenchyme of the endocardial cushion between E12 and E14. Our results suggest that BMP-2 and MSX-2 are tightly linked to the formation of the atrioventricular junction and valves and that BMP-4 is involved in the development of the outflow tract myocardium and of the endocardial cushion. In addition, BMP-2, BMP-4 and MSX-2 and apoptosis seem to be associated with differentiation of the endocardial cushion.

Age-dependent changes in the expression of matrix components in the mouse eye

Although the presence of 'cartilage-specific' collagens in the eye has been documented earlier, very little is known about their synthesis rates during ocular development, growth and aging. The purpose of the present study was to follow changes in the mRNA levels and distribution of key components of the extracellular matrix in the eyes of normal and transgenic Del1 mice, harboring a short deletion mutation in the type II collagen gene, during ocular growth and aging. Total RNAs extracted from mouse eyes were studied by Northern analysis for mRNA levels of type I, II, III, VI, IX and XI collagens, biglycan, fibromodulin and decorin. A predominant finding of the present study was the marked reduction in the mRNA levels of type I and II collagens in the eye upon aging. The changes in the mRNA levels of type III and VI collagen and proteoglycans were smaller. Localization of type II and IX collagen in the eye was performed by immunohistochemistry. Despite the reduction in the type II collagen mRNA levels, immunohistochemistry confirmed widespread distribution of the protein also in aging mouse eyes, suggesting its slow turnover. Although the Del1 mutation caused gradual degenerative lesions in the eyes, the distribution of the protein remained essentially unchanged. The widespread distribution and marked downregulation of type II collagen production in the mouse eye upon aging probably explain the gradual development of degenerative lesions, particularly in the eyes of transgenic Del1 mice, where production of mutant type II collagen chains also contributes to the process.

Identification of alpha6beta1 integrin positive cells in synovial lining layer as type B synoviocytes

OBJECTIVE

In rheumatoid arthritis (RA) the synovial lining is responsible for cartilage destruction. Laminin is one of the major matrix molecules surrounding the lining cells. We investigated the laminin adhesion mechanism of synovial lining cells by analyzing the presence of its receptor, alpha6beta1 integrin, on type A and type B synoviocytes.

METHODS

The alpha6 integrin subunit and a macrophage marker were simultaneously localized by immunohistochemistry in 29 RA derived, 6 osteoarthritis derived, and 2 healthy synovial samples by light and electron microscopy. We also used enzyme treatments to release cells from synovial tissue samples and localized the same antigens on adherent cells.

RESULTS

The alpha6beta1 integrin positive cells were localized in basal areas of the lining layer and many of them were negative for the macrophage markers. By immunolabeling electron microscopy the alpha6 integrin positive cells were confirmed to represent the fibroblast-like type B cells. Further, in freshly isolated synoviocyte cultures the type B cells were positive for alpha6 integrin, whereas all other cell types were negative for this laminin receptor.

CONCLUSION

Integrin alpha6beta1 is known to be a laminin receptor of endothelial cells, adipocytes, and macrophages, not usually expressed on fibroblasts. However, in synovial lining layer it is expressed on fibroblastic type B cells, but the macrophage population is negative. The unique characteristics of synovial lining cells distinguish them from other connective tissue cells and must be taken into account in all considerations of the pathogenic mechanisms of rheumatoid disease.

Management of testicular cancer--16 years' experience from southwest Finland

OBJECTIVE

This study investigated the outcome of testicular cancer treatment in Finland.

MATERIAL AND METHODS

Data on 88 testicular cancer patients treated in Turku University Central Hospital between 1976 and 1992 were studied to analyse outcome and survival.

RESULTS

The histological diagnosis was seminoma for 39 patients and non-seminoma for 49 patients. Two seminoma patients relapsed (5%) and one patient died of progressive disease (3%; initially stage II seminoma). Eleven non-seminoma patients relapsed (22%), nine of whom were cured with chemotherapy. Four non-seminoma patients died of progressive disease (8%; initially one stage I non-seminoma and three stage III non-seminomas). The median time to relapse after the completion of treatment was 9 months (range 3-50 months). Non-seminoma patients had significantly more relapses than seminoma patients (p = 0.03). Most relapses (73% of the non-seminoma relapses) were found among the stage I non-seminoma patients who had not received adjuvant chemotherapy, while none of the stage I seminoma patients relapsed (p = 0.007).

CONCLUSIONS

Close surveillance is important for all non-seminoma patients to guarantee the early detection and treatment of recurrent disease. Treatment and surveillance should be covered by national guidelines and be conducted in centres with special interest in this rare but mostly curable cancer.

Heat shock proteins, HSP25 and HSP70, and apoptosis in developing endocardial cushion of the mouse heart

Formation of the atrioventricular channels and valves from the endocardial cushion occurs through growth and remodeling of the initial endocardial cushion. This process requires balanced coordination of proliferation and apoptosis by still unknown factors. To detect a possible role for the heat shock proteins 25 and 70 (HSP25 and HSP70) as apoptosis-associated proteins and differentiation factors in the development of the endocardial cushion, we analyzed their temporal and regional occurrence during cell proliferation and apoptosis in E11-E17 embryos. The distribution and timing of these events and factors were consistent with the hypothesis that HSP25 is related to myocardial development whereas HSP70 is related to differentiation of the endocardial cushion by cell proliferation and apoptosis.

Effect of etoposide on experimental testicular teratoma in 129/SvJ mice

To study the effects of etoposide on experimental testicular teratoma in 129/SvJ mouse we analysed the tumour growth, differentiation, apoptosis and the localisation of mdr1 P-glycoprotein (mdr1-Pgp). In this model the implanted gonadal ridges developed into testicular teratomas in 17 out of 56 implanted testes (30%) and in 14 out of 28 mice (50%). The tumour-bearing mice were treated with etoposide on 4 successive days either 4 weeks or 6 weeks after implantation, and killed 7 days after the last dose. The mice in the control groups did not receive etoposide. The teratomas consisted mainly of neural tissue. The etoposide-treated 4-week teratomas, but not the 6-week teratomas, were significantly smaller than those in the corresponding control groups. The density of apoptotic cells and the distribution of the mdr1-Pgp were not altered by etoposide. The decreased proportion of immature neuroectodermal tissue components was observed in all treated teratomas, converting the histology towards that of a mature teratoma. In addition, a low proportion of immature tissue components was frequently combined with a low density of apoptotic cells. In conclusion, etoposide decreased the immature tissue components of teratomas, while mature tissues remained unaffected. These results may have clinical relevance in man, since they confirm that postchemotherapy mature teratomas cannot be treated with chemotherapy. Despite benign histology, the human residual tumours have a significant malignant potential and require complete surgical excision and close surveillance.

Sox9 protein in rat sertoli cells is age and stage dependent

We studied the location of Sox9 protein in the embryonic, juvenile, and adult rat testis by immunohistochemistry and immunoblotting. Sox9 belongs to a family of Sox proteins that are transcription factors and important in several developmental processes. In the incipient embryonic testis, Sox9 was prominently present in the gonadal blastema. With further embryonic differentiation, Sox9-positive cells arranged in the periphery of the testicular cords, showing the location of the Sertoli cells. Thereafter the immunoreaction for Sox9 gradually declined and was only weakly detectable in the 2-day-old postnatal rat testis. This situation remained for some period of time. In the 15-day-old rat testis, Sox9 protein strongly reappeared in the testicular cords. In the adult, the Sertoli cells of most regions of the seminiferous tubules were positive for Sox9. The strongest reaction for Sox9 was found in the dark zone. However, clearly negative or only weakly positive spermatogenic stages for the protein were also found, as seen for example in the pale zone. In fertile 1-year-old rats this basic situation was still detectable. Analyzed rat ovaries were all negative for Sox9, showing the sex-specific nature of Sox9. The results showed that Sox9 protein is distinctly present in the developing and mature Sertoli cells, but that its presence and amount is dependent on the age and the spermatogenetic stage within the seminiferous tubuli. The prominent presence of Sox9 in the incipient testis and at puberty suggests that this protein is needed at important phases of aggregation and reorganization of the Sertoli cells. The age and stage-specific presence of Sox9 in the testicular cords and in the seminiferous tubules of the adult suggests that Sox9 also may have a pivotal role in germ cell differentiation.

Apoptosis in the pattern formation of the ventricular wall during mouse heart organogenesis

Apoptosis is an important mechanism in organogenesis, but its role in heart development has been poorly characterized. We have here studied apoptosis in the developing ventricular wall of mouse embryonic heart. Developing mice hearts on days 11 to 16 of gestation were studied using in situ end-labeling of degraded DNA (TUNEL), immunocytochemistry of regulatory genes Bcl-2 and Bax, and light and electron microscopy. TUNEL end-labeled apoptotic cells were found in the ventricular wall on days 11 to 16 of gestation. The proportions of apoptotic cells of all cells in the ventricular wall differed between the trabecular and compact regions (P = 0.003) and between the days of gestation (P = 0.0001), the calculated apoptotic index was greater in the compact region at all ages except day 14. Ultrastructural analysis showed typical apoptotic shrinkage, chromatin degradation, and apoptotic bodies in several myoblastic and myocardial endothelial cells which were also positive by DNA end-labeling. Immunocytochemical reaction for the apoptosis checkpoint proteins in the ventricular wall showed clearly more Bcl-2 positive cells than Bax positive cells. The numerical densities of all cells in the compact and trabecular regions remained always higher in the compact region (P = 0.04) despite the fact that apoptosis was present in both areas at the same time. In conclusion, apoptosis takes place in the developing myocardial muscle as well as the myocardial endothelium during ventricular morphogenesis on days 11 through 16 and decreases clearly on day 16. We suggest that apoptosis and its regulatory factors are closely involved in the morphogenesis of the ventricular wall of the mammalian heart.

Presence of anti-Müllerian hormone correlates with absence of laminin alpha5 chain in differentiating rat testis and ovary

The distribution of anti-Müllerian hormone (AMH) and laminin (Ln) alpha5 chain in differentiating rat testis and ovary were studied by immunohistochemistry. In the incipient embryonic male gonad a weak reaction for Ln alpha5 chain, but not for AMH, was detected. With further prenatal development, Ln alpha5 chain rapidly disappeared from the basement membrane (BM) of the incipient testicular cords in parallel with the appearance of AMH in the Sertoli cells. After birth, Ln alpha5 chain reappeared in the BMs of the cords with the decline and disappearance of AMH from the respective Sertoli cells. In the corresponding stages of the ovary, Ln alpha5 chain was present in the BM of the prenatal gonadal cords and in postnatal primordial follicles. The cells of those epithelia were negative for AMH. With the growth of the follicles, Ln alpha5 chain disappeared from the BM when AMH appeared in the epithelial follicular cells. The present results show that male and female gonadal epithelia negative for Ln alpha5 chain were positive for AMH, and that epithelia positive for Ln alpha5 chain were negative for AMH. Thus, epithelial Ln alpha5 chain and AMH as a product of the same cell seemed to exclude each other. The results require an explanation why Ln alpha5 chain has to be excluded from the BM of the epithelia during the secretion of AMH chain through the basal cell membrane to the surrounding tissues where it executes its important biological functions. These observations suggest a hypothesis that the production of both components is regulated by the same gene and factor system.

Characterization of the model for experimental testicular teratoma in 129/SvJ-mice

An animal model of experimental testicular teratoma has been established to study how a teratoma affects the host testis and how the host testis reacts against the teratoma. 129/SvJ-mice were used as experimental animals. To induce the experimental testicular teratoma, male gonadal ridges from 12-day-old 129/SvJ-mouse fetuses were grafted into the testes of adult mice for 1-12 weeks. The developing tumour was analysed by light and electron microscopy and by immunocytochemical localization of transcription factors SOX9 and c-kit, glial fibrillary acidic protein (GFAP) and type IV collagen. Testicular teratoma was observed in 36 out of 124 testes with implanted fetal gonadal ridges (frequency 29%). One spontaneous testicular teratoma was observed in this material from 70 male mice (1.5%). One week after implantation intracordal clusters of cells were seen in embryonic testicular cords of the graft as the first sign of testicular teratomas. Four weeks after implantation the embryonic testicular cords had totally disappeared from grafts with teratomas, and the tumour tissue had enlarged the testis and invaded the interstitium of the host testis. It consisted of solitary pieces of immature cartilage as well as of glial cells and of primitive neuroepithelium. Six to eight weeks after implantation the tumour tissue had expanded so that the enlarged testis could be detected by macroscopic enlargement of the scrotum. The testicular tissue of the host had practically disappeared, and only solitary disrupted seminiferous tubules of the host were seen surrounding the teratoma. Neuroepithelial structures of some teratomas cultured for 8 weeks had cells with a granular nucleus as a sign of obvious apoptosis. Eleven to 12 weeks after implantation the growth of the teratoma had stopped, and the histology corresponded to that of a mature cystic teratoma. GFAP, SOX9 and type IV collagen were strongly positive in some parts of the tumours cultured for 4 and 8 weeks, while only occasional c-kit-positive areas were observed in tumours cultured for 8 weeks. As conclusions: (1) the metastasizing capacity of the experimental testicular teratoma is very low during 12 weeks, but the behaviour of the tumour in the testicular tissue of the graft is invasive; (2) the growth of experimental testicular teratomas cease 6-8 weeks after implantation of the fetal gonadal ridges with the obvious apoptosis of the immature tissue components; (3) the model of experimental testicular teratoma in the mouse is suitable for studying how the teratoma affects the host testis and how the host testis reacts to teratoma.

Experimental testicular teratoma promotes formation of humoral immune responses in the host testis

The testis is an immunologically privileged site. Very little is known about the factors regulating formation of immune responses elicited by a neoplasm in the testis. We have studied the immune response of the host testis against experimental testicular teratoma in mouse by localizing adhesion molecules (CD106, CD54, CD49d/CD29, CD44, CD18, CD8 and CD4), cytokines (IL-2, IL-4, IL-6, IL-10 and IL-12), T-cell costimulators (CD80, CD86) and the lipid antigen presenting molecule CD1d in the testis of 129/SvJ mice with and without experimental testicular teratoma. The testicular teratomas were induced by grafting male gonadal ridges from 12-day-old 129/SvJ mouse fetuses into testes of adult mice from the same strain. The tumors cultured intratesticularly for 2, 3, 4 and 8 weeks (three animals per time point) were used for immunocytochemistry. CD1d was detected in Sertoli cells and in some degenerated tubules of the host testis surrounding the graft. In the tumor, CD1d was detected in glandular epithelia, smooth muscle and in thin fibers of neural origin. IL-2 was observed in some blood vessels of the host testis and of the tumor and in occasional cell infiltrates around these vessels. Some tubular structures of the tumor were also positive for IL-2. IL-6 was detected in Sertoli cells of the normal testis and in Sertoli cells and in solitaryinterstitial cells as well as in the walls of some blood vessels of the host testis. The reaction for IL-6 was more prominent in the tubules apparently damaged by the growing tumor. In the tumor IL-6 was detected in epithelial structures, muscle cells, in thin fibers of neural origin and in some blood vessels. IL-10 was detected in individual cells in the interstitium and in degenerating tubules of the host testis. In the tumor the epithelial structures were positive for IL-10. The interstitium of the host testis was positive for CD106 and the embryonic testicular cords in the graft were also positive, but the tumor was negative. CD44 and CD18 were observed in some blood vessels and in degenerated tubules of the host testis. In the tumor CD44 and CD18 were occasionally observed in cartilage and in epithelial structures. The results of the present study suggest that cytokine microenvironment in the testis containing neoplastic tissue promotes activation of humoral immune responses. In addition, as the damaged seminiferous tubules expressed increased amounts of two cytokines promoting humoral immune responses, IL-6 and IL-10, it is possible that also in other conditions with damage to the tubules, humoral immune responses predominate.

Sex-specific localization of laminin alpha 5 chain in the differentiating rat testis and ovary

The localization of laminin (Ln) alpha 5, beta 1 and beta 2 chains in the differentiating rat testis and ovary was studied by immunolabeling light and electron microscopy. The initial formation of the male and female gonadal blastemas included an emergence of Ln alpha 5 and beta 1 chains, but not of Ln beta 2 chain. The sexual differentiation of the embryonic male gonadal cords included rapid sex-specific disappearance of the incipient Ln alpha 5 chain. The rete testis cords, in contrast, remained positive for Ln alpha 5 chain. In the postnatal testis, the Ln alpha 5 chain reappeared in Ln beta 1 chain-positive cord basement membranes, which also became positive for Ln beta 2 chain. The differentiating myoid cells also gradually became positive for both Ln alpha 5 and Ln beta 1 chains. In the ovary Ln alpha 5 chain persisted in BMs of the cords throughout the fetal phase. Small and newly formed follicles in the early postnatal rat ovary were also positive for Ln alpha 5 chain, whereas growing and large follicles were negative. During the early postnatal phase, Ln beta 1-chain positive follicular BMs became also positive for the Ln beta 2 chain. Basement membranes of testicular and ovarian surface epithelia contained the Ln alpha 5 chain throughout the study. The blood vessels of the male and female gonad showed differentiation-dependent variation in their reactivity for the Ln alpha 5 and beta 2 chains. The present results show that the Ln alpha 5 chain is an early molecular marker for sexual differentiation, which therefore may be regulated by the testis-determining factors. The results also show that in the early postnatal rat ovary, the follicular basement membranes are heterogeneous in their Ln content, which may offer a means to distinguish different follicular populations from each other and to identify the different stages of follicular growth.

The polysialic acid units of the neural cell adhesion molecule N-CAM form filament bundle networks

Polysialic acid is a developmentally regulated component in the neural cell adhesion molecule N-CAM which also occurs as the capsular polysaccharide of bacteria causing meningitis. Polysialic acid has been considered as a repulsive element that regulates intermolecular and intercellular adhesion. Using atomic force microscopy we unexpectedly find that oligomers of polysialic acid assemble with each other into filament bundle networks. Filaments were formed from oligomers containing 12 or more N-acetylneuraminic acid residues, and they were sensitive to sialidase digestion. The networks were also formed by the polysialic acid-containing carbohydrate units of N-CAM. The formation of filament bundles is a novel and unexpected property of polysialic acid and of short carbohydrate oligomers in general and represents a previously unrecognized molecular interaction mechanism which impacts both eukaryotic and prokaryotic cell-cell adhesions.

Cellular and molecular changes during sex differentiation of embryonic mammalian gonads

Structural and molecular changes during sex differentiation and development of mammalian gonads from early embryonic phase until sexual maturity have been studied by morphologic and immunocytochemical methods in vivo and in experimental culture. The strategy has been to identify cellular macromolecules whose genes are differently expressed in the two sexes and to formulate a hypothetical regulatory chain of sex determination. This approach should provide new possibilities for finding the missing links between the final structural genes and the early regulatory genes, which are differentially expressed before and during gonadal differentiation. On the basis of accumulated structural and molecular evidence, the early epithelial differentiation from the precursor cells via cell aggregates to testicular cords or ovarian follicles is not sexually regulated. The biological consequences of sex determination in the differentiation of the genital organs include changes in the pattern formation of the gonadal epithelia and concomitant alterations in the synthesis and organization of the structural macromolecules.

Differential distribution of type IV collagen chains in the developing rat testis and ovary

The localization of type IV collagen alpha 1-alpha 5 chains in the differentiating rat testis and ovary was studied by immunocytochemistry. The initial formation of the testis and ovary included the appearance of collagen alpha 1/alpha 2(IV) chains in the gonadal blastemas. Upon further differentiation of the epithelia of the gonads alpha 1/alpha 2(IV) chains became localized in all of the respective basement membranes (BMs). The alpha 3, alpha 4 and alpha 5 chains of type IV collagen were not detectable in the prenatal rat testis and ovary. With the postnatal differentiation of the rat testis the alpha 3-alpha 5(IV) chains gradually appeared, and were localized in BMs of the testicular cords and seminiferous tubules, rete cords, myoid cells, surface epithelium, Leydig cells, and in some blood vessels. In the postnatal rat ovary, the alpha 3(IV) chain appeared in the BMs of small cortical follicles whereas the BMs of secondary and more deeply localized follicles were devoid of this chain. The alpha 1/alpha 2(IV) chains were abundant in the theca. A reaction for alpha 3-alpha 5(IV) chains also appeared in the BM of the ovarian surface epithelium and of some blood vessels after birth. The present results show that the alpha 3-alpha 5(IV) chains are not only less widely distributed than the alpha 1/alpha 2(IV) chains but are also synthesized much later in development. The late appearance of the alpha 3-alpha 5(IV) chains shows that the development of the mature testicular and ovarian BMs is a long process and that the time schedule for the synthesis of these chains is different from that of many other extracellular matrix proteins. A careful analysis of the expression of alpha 3(IV) chain may be useful in the further study of the kinetics and regulation of ovarian follicular growth.

Computer analysis of living cells: movements of the chromatoid body in early spermatids compared with its ultrastructure in snap-frozen preparations

Quantitative analyses of cytoplasmic and nuclear organelle movements in living interphase cells at defined stages of differentiation are few. By phase contrast videomicroscopy and digital imaging techniques, we have traced the path of the chromatoid body (CB) and analysed its rapidly changing positions in relation to the nuclear envelope, Golgi complex and nuclear pale chromatin areas in living early spermatids of the rat. The CB had intimate interactions with the nuclear envelope and moved both in parallel and perpendicular fashion in relation to it. It had successive short contacts with the Golgi complex and nuclear pale chromatin areas. It was also seen to scan between two pale chromatin areas and it had pinocytosis-like transient engulfments during interactions with the pale chromatin. In ultrastructural analysis of snap-frozen preparations, the CB had a large contact area with the nuclear envelope with several intermediate organelles that may be involved in nucleocytoplasmic material transport. It is evident that quantitative image analysis of living cells is a powerful guide for ultrastructural analyses. The snap-freezing technique gives new possibilities for studies of structures that are sensitive to conventional fixation procedures.

HLA-B27 modulates intracellular survival of Salmonella enteritidis in human monocytic cells

Human major histocompatibility complex class I allele HLA-B27 is associated with a group of diseases called spondyloarthropathies. In reactive arthritis (ReA), the disease is triggered by certain infections, e.g. gastroenteritis caused by Salmonella. The host/microbe interaction is abnormal in susceptible individuals leading to inefficient elimination of arthritis-triggering bacteria, fragments of them, or both, after the initial infection. Using transfected human monocytic U937 cell lines, we demonstrate that the expression of the HLA-B27 antigen does not influence the uptake of S. enteritidis into U937 cells in vitro. Interestingly, HLA-B27 remarkably impairs the elimination of S. enteritidis within the HLA-B27 transfected U937 cells. The impaired elimination of ReA-triggering microbes by HLA-B27+ monocytes may offer an explanation for the persistence of ReA-triggering microbes in susceptible HLA-B27+ individuals. This modulation of the host/microbe interaction by HLA-B27 may have an important role in the pathogenesis of ReA.

The intermediate filament protein nestin occurs transiently in differentiating testis of rat and mouse

Nestin is an intermediate filament (IF) protein (IFP) which occurs during early developmental stages and during regenerative processes in muscle and neuronal cells. The spatial and temporal localization of nestin in the developing testis of rat and mouse was studied by immunolabeling light and electron microscopy and by immunoblotting. Nestin localization was related to the localization of the other major IFPs specific for this tissue, i.e. cytokeratins, vimentin and desmin. Laminin immunocytochemistry and conventional microscopy were used to identify tissues and cells. With the incipient differentiation of the gonadal anlage, the reaction for nestin was weak in the gonadal ridge, whereas the cells of the mesonephric mesenchyme showed a prominent reaction for this IFP. The nestin-specific reaction in the epithelial mesonephric duct and tubules was weak and disappeared at an early phase of differentiation. With the development of the testis proper, nestin was transiently found in several cell types. Nestin was found as well as vimentin and cytokeratins in the Sertoli cells. In the interstitial cells nestin was found together with vimentin and desmin IFPs, and was most prominent in the differentiating myoid cells. After birth, nestin gradually disappeared from the testicular cells and in the rat at puberty was found only in the endothelial cells of some blood vessels. The abolished nestin synthesis in the testis was confirmed by immunoblotting. These results suggest that nestin is required transiently during the development of the testis and mesonephros. The temporary presence of nestin, and several other IFPs during these phases, coincides with key phases of urogenital sex differentiation. This may imply that the orchestrated synthesis of the IFPs nestin, cytokeratins, vimentin and desmin is likely to be linked with the genes regulating sex differentiation.

Survival and degradation of Salmonella enterica serotype Enteritidis in intestinal epithelial cells in vitro

The survival and fate of Salmonella enterica serotype Enteritidis in Henle-407 human intestinal epithelial cells was investigated during prolonged incubation to evaluate the persistence of causative microbes and the relationship to patients developing reactive arthritis. Most of the bacteria were killed and degraded quite soon after infection of the cells, but there were still live bacteria inside the cells for up to 14 days. These results suggest that in patients developing reactive arthritis the salmonellae could persist in the epithelial cells and spread within the host to the joint and be present there at the time of the inflammatory response. Production of marked amounts of nitric oxide was observed as a novel response to salmonella infection in human intestinal epithelial cells. The present experimental procedure appears to be a suitable model to further investigate host-bacteria interaction in HLA-B27 positive cells from patients developing reactive arthritis.

Identification of the reactive subunits of Aspergillus umbrosus involved in the antigenic response in farmer's lung

BACKGROUND

Farmer's lung (FL) is the most common form of extrinsic allergic alveolitis and the fungus Aspergillus umbrosus has frequently been associated with FL among Finnish farmers. IgG and IgA class antibodies against Aspergillus umbrosus are found in the serum of FL patients and healthy exposed farmers. So far the immunologically reactive subunits of Aspergillus umbrosus are unknown.

OBJECTIVES

The purpose of the study was to identify and localize the reactive subunits of Aspergillus umbrosus that are involved in the antigenic response in FL.

METHODS

The distribution of the primary antibody on the outer wall layers of 4- and 11 day-old fungi Aspergillus umbrosus was studied by pre-embedding immunolabelling with fluorescein isothiocyanate (FITC)- and gold-conjugated antibodies. The surface carbohydrates of the outer wall layers were studied using FITC-conjugated lectins.

RESULTS

FITC-conjugated antibodies from FL patient sera reacted with spores (conidia), phialides and hyphae, whereas the fruiting body, cleistothecia, remained unstainable. Immunofluorescence labelling was confirmed by immunolabelling electron microscopy, and gold-conjugated IgG antibodies were found on the outer cell walls of spinulose conidia, and in a less degree on the outer cell walls of hyphae and phialides. Only single gold particles were found scattered on the surfaces of cleistothecia. The surface carbohydrates of Aspergillus umbrosus conidia, vesicles, phialides and hyphae had a high affinity to GlcNAc beta 1- and Man alpha 1-/Glc alpha 1-specific lectins and only GlcNAc beta 1-specific lectins also reacted with the outer cell walls of cleistothecia. Blocking of the antigenic sites of Aspergillus umbrosus by preincubating antigen-coated enzyme linked immunosorbent assay (ELISA) plates with lectins caused some inhibition, indicating that sites with the highest affinity for lectins were not always antigenic sites.

CONCLUSION

Gold-and FITC -conjugated antibodies were distributed mostly on the outer wall layers of conidia, hyphae and phialides of Aspergillus umbrosus and GlcNAc beta 1-linked lectins had the strongest affinity to the outer wall layers.

Reactions of Leydig cells and blood vessels to lymphoblastic leukemia in the rat testis

The testis is the third common site of relapse in childhood acute lymphoblastic leukemia (ALL). Despite the apparent clinical importance of testicular relapse, its pathogenesis is still unknown. The studies with an animal model of ALL have shown that many testicular factors are able to control the intratesticular infiltration and proliferation of leukemic lymphoblasts during the untreated course of ALL. In the present study, the ultrastructure of rat testicular interstitium infiltrated by leukemic lymphoblasts was studied in two groups of rats transplanted with rat T cell leukemia in early and late puberty. In both groups most of the leukemic cells infiltrating testicular interstitium were totally or partly enveloped by one or more Leydig cells, and the endothelial cells of capillaries, arterioles and venules were hypertrophic. The Leydig cells of the younger experimental group were by nuclear and cytoplasmic ultrastructure similar to the undifferentiated Leydig cells normally seen on the third postnatal week. The results suggest that Leydig cells bind leukemic lymphoblasts on their surface in vivo as also previously observed in vitro, and that ALL may disturb the pubertal maturation of Leydig cells. The occlusion of arterial and capillary lumina by folds of hypertrophic endothelial cells together with adhered leukemic lymphoblasts may impair the circulation of leukemic testes.

Differential distribution of laminin chains in the development and sex differentiation of mouse internal genitalia

The distribution of laminin chains and basement membranes (BMs) in the ontogenesis and sex differentiation of male and female mouse gonads and mesonephros was studied by conventional and immunocytochemical light and electron microscopy. The alpha 1 (synonymous to A) chain was recognized with MAbs against fragment E3, and three chains of laminin with PAbs raised against EHS-laminin. BMs, which formed around the mesonephric duct, the mesonephric tubules, and the paramesonephric duct, contained the laminin alpha 1 chain. The alpha 1 chain appeared with epithelial differentiation in the developing gonads in both sexes. The alpha 1 chain was first evident around the embryonic gonadal cords and remained, after development, in the BMs of the testicular cords and ovarian follicles. The laminin alpha 1 chain was also detected in BMs of the myoid cells around the epithelial rete cords, and transiently in the surface epithelium and in the corpus luteum. Laminin beta-gamma chains were found in many locations where the alpha 1 chain was not detected. These included the mesenchyme of the early mesonephros, the BMs of blood vessels and surface epithelium in the differentiated testis and ovary, between the theca cells in the ovary, and in some corpora lutea. The morphological differentiation of the BMs of the embryonic testicular cords proceeded rapidly. In contrast, the BM of the ovarian cords remained relatively poorly differentiated during the prenatal phases, and developed concomitantly with the differentiation of the follicles. The results show that BMs in the differentiating internal genitalia are heterogeneous with respect to their laminin chains, and suggest that all known laminin chains must be analyzed in the differentiation of gonadal epithelia for a complete role of the BMs in gonadal sex differentiation.

Alpha 6 subunit of integrins in the development and sex differentiation of the mouse ovary

The localization of the alpha 6 subunit of integrins in the ovary was studied by conventional and immunolabeling light and electron microscopy starting from the pregonadal embryonic phase until adulthood. The formation of gonadal blastema cells included an initial expression of the alpha 6 subunit on the plasma membranes of all blastema cells. Subsequently the reaction for the alpha 6 subunit became restricted in groups of these cells, which differentiated into gonadal cord cells, the precursors of follicular cells. The alpha 6 subunit was also found in the cells of the mesonephric duct, mesonephric tubules, and the ovarian rete. Reorganization of the gonadal cords into follicles at birth was accompanied with strong and uniform re-expression of the alpha 6 subunit on the surface of the cord cells. Vascular endothelial cells and the cells of the postnatal surface epithelium remained positive for the alpha 6 integrin subunit. In larger follicles, the intensity of the reaction for the integrin subunit varied. The theca cells of growing follicles contained the alpha 6 subunit. The results show that this subunit of integrins is present in phases of increased adhesion and aggregation, and that its expression probably is involved in the regulation of ovarian epithelial differentiation. The distribution of alpha 6 integrin in ovarian cells shows potentially important sex-specific and developmental differences in epithelial organization when compared with respective changes found earlier by us in the male gonad.

Induced ablation of gonadotropins in transgenic mice expressing herpes simplex virus thymidine kinase under the FSH beta-subunit promoter

Suppression of gonadotropins was induced by gancyclovir or acyclovir treatment in transgenic mice carrying 2.3 kb of bovine follicle-stimulating hormone beta (FSH beta) promoter fused to Herpes simplex virus thymidine kinase (tk) coding sequence. Transgenic tk and endogenous FSH beta were immunohistochemically co-localized in the same pituitary cells. In adult castrated transgenic males, gancyclovir treatment reduced plasma FSH (30%, P < 0.001). In intact juvenile gancyclovir treated mice, the reduction of pituitary FSH, and in males also of plasma FSH, was greater (50-70%, P < 0.05-0.01). A concomitant suppression of luteinizing hormone (LH) (50%, P < 0.01) was observed in female pups. The most pronounced reduction of gonadotropins was observed in newborn transgenic pups treated in utero with acyclovir. Both males and females had significantly lower pituitary levels of FSH (75-55%), LH (80-90%) or both (P < 0.05-0.01). Less pronounced decreases (30-40%, P < 0.01) were observed in plasma FSH. No apparent defects were seen in the testes of the transgenic, acyclovir treated, newborn pups. This mouse model is applied to study the dynamics of the gonadotropes and the role of gonadotropins in the maturation of the reproductive functions.

Differential distribution of the alpha 6 subunit of integrins in the development and sexual differentiation of the mouse testis

The distribution of the alpha 6 subunit of integrins in the development and sexual differentiation of mouse testis was analyzed by light and electron microscopy during the embryonic, fetal and early postnatal periods. At the pregonadal phase only the epithelial cells of the mesonephric duct and of the distal mesonephric tubules showed a reaction to alpha 6, whereas the surface epithelium and the mesenchyme of the mesonephros were negative or contained only a rudimentary amount of the alpha 6 subunit. With the formation of the gonadal ridge and the testicular blastema, the gonadal cells became positive for the alpha 6 subunit. This expression remained in embryonic cord cells and in the vascular endothelial cells, whereas the differentiating cells of the surface epithelium, tunica albuginea, the Leydig cells, and the interstitial mesenchymal cells were negative. With the fetal and postnatal differentiation, the expression of the alpha 6 subunit gradually diminished in the cord cells, and by the prepubertal phase, alpha 6 was found only at adhesion sites between some Sertoli cells. Similar changes were seen in the mesonephric duct and tubules, and in the rete cords. The presence of alpha 6 in regions undergoing developmental cell aggregation processes and their disappearance during tissue maturation, suggest that alpha 6 plays a specific but transient role in gonadal cell adhesion necessary for the histogenetic organization of the testis. In addition to its role in developing and organizing cells, alpha 6 integrin was also a prominent component in degenerating cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Electron microscopy and immunolabeling of Yersinia antigens in human synovial fluid cells

Recent findings have emphasized the involvement of bacterial antigens in synovitis in reactive arthritis. It is still unclear, however, in what form the microbial material exists in the joint. Both antigen-containing cells and intact bacteria have been proposed as candidates on the basis of immunohistochemical studies of the synovial membrane. This study addresses that question by electron microscopy and peroxidase immunolabeling of synovial fluid cells from three patients with reactive arthritis triggered by Yersinia enterocolitica O:3. For all three patients a diffuse reaction in the cytoplasm of phagocytes was interpreted as bacterial material in a degraded form. These results are consistent with our proposal that intact bacteria rarely, if ever, enter the joints of Yersinia-triggered reactive arthritis patients.

Abnormal pulmonary macrophages in lysinuric protein intolerance. Ultrastructural, morphometric, and x-ray microanalytic study

Pediatric patients with lysinuric protein intolerance are predisposed to develop alveolar hemorrhage and pulmonary alveolar proteinosis. We evaluated the ultrastructural features of pulmonary alveolar proteinosis and the potential abnormality of pulmonary macrophages in lysinuric protein intolerance. Lung tissue specimens obtained at autopsy were examined by transmission electron microscopy. Pulmonary macrophages from bronchoalveolar lavages were studied by electron microscopy, morphometry, and x-ray microanalysis and compared with control cells. The macrophages of patients with lysinuric protein intolerance contained significantly more multilamellar structures than did control cells and showed electron-dense material identified to contain excess iron. The predisposition to develop alveolar proteinosis and the abnormal ultrastructure of pulmonary macrophages suggest altered phospholipid metabolism in patients with lysinuric protein intolerance. The marked intramacrophageal accumulations of iron might indicate altered iron metabolism or subclinical hemorrhages in lung tissue.

Intermediate filament proteins and epithelial differentiation in the embryonic ovary of the rat

The development and sexual differentiation of gonads in female rat embryos and fetuses between the ages of 11 and 17 days was studied by immunocytochemical analysis of intermediate filament proteins and laminin by light and electron microscopy. In the 11-day-old pregonadal embryo, the surface epithelial cells in the ventral cortex of the mesonephros contained desmin but not cytokeratin or vimentin. The development of the gonad began on the following day by proliferative growth of the mesonephric surface cells, which like the subepithelial cells soon expressed vimentin in addition to desmin. The differentiation continued by formation of separate epithelial cell clusters, which joined into cords, irregular in shape and size. Desmin disappeared from the cord cells and cytokeratins appeared while vimentin remained in all somatic cell types. Desmin was especially abundant in some stromal cells adjacent to the epithelial tissues. After the segration of the basic ovarian tissues, vimentin and desmin decreased and cytokeratins appeared in the surface epithelial cells. New changes in cytokeratin expression appeared with the differentiation of the embryonic cords in a sex-specific manner with gradual decrease of reactivity for cytokeratin 18. No immunoreaction to the neurofilament proteins was found at the present ages, and the germ cells were negative for intermediate filaments. The results show that desmin is expressed in several primitive ovarian and mesonephric cells even though they are not myogenic.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrastructure and morphometry of testicular Leydig cells and the interstitial components correlated with testosterone in aging rats

The ultrastructure of testicular interstitium in young and aged adult rats was analysed using morphometric methods, and the plasma testosterone concentration was measured. With increasing age there was an augmentation in the volume of collagen fibrils in the intercellular matrix and in blood vessels. During the aging process (approximately two years) the average volume of the Leydig cell decreased from 1364 microns 3 to 637 microns 3, but the number of Leydig cells in paired testes increased from 53 x 10(6) to 113 x 10(6). The absolute volume of smooth surfaced endoplasmic reticulum (SER) per Leydig cell amounted in aged rats to 78% of that in young adult rats. The total amount of SER in paired testes increased by 62% with aging. The present analysis suggests that the ability of SER to maintain peripheral testosterone concentration decreases with age. In young adult rats the absolute volume of peroxisomes per Leydig cell correlated significantly with the concentration of testosterone in blood and also with the absolute volume of SER per Leydig cell. These results combined with ultrastructural observations of close apposition of peroxisomes and SER suggest that peroxisomes have a role in testosterone secretion by Leydig cells.

Fetal Leydig cells: cellular origin, morphology, life span, and special functional features

The Leydig cells, responsible for testicular androgen production, have two growth phases during the life-span of mammals. The fetal population appears during fetal life and is responsible for the androgen-induced differentiation of the male genitalia. The fetal Leydig cells disappear after birth, and the other population, the adult Leydig cells, appears during puberty and persists for the whole adult life. The fetal Leydig cells, evidently due to the intrauterine endocrine milieu and their special functional requirements in genital differentiation, differ both morphologically and functionally from the adult population. The purpose of this review is to elucidate the special features of the mammalian fetal Leydig cell population, which presents an intriguing experimental model for studies of function and regulation of steroidogenic cells.

Lectin-binding carbohydrates in sexual differentiation of rat male and female gonads

Development and sexual differentiation of the mammalian gonad involve changes in the type and distribution of different proteins and glycoproteins in and around the epithelial gonadal cords, the future seminiferous tubules in the testis, and follicles in the ovary. To study changes in cellular carbohydrate-containing compounds in the sex-specific morphogenesis of rat gonads, sections from embryonic, fetal and early postnatal gonads were labelled with seven different fluorescein isothiocyanate (FITC)-conjugated plant lectins of various carbohydrate-binding specificities. Double labelling of laminin with tetramethylrhodamine isothiocyanate (TRITC)-conjugated antibodies was used to outline the epithelial tissues. From the results we conclude that the abundance and similar distribution of carbohydrates in the early gonads of both sexes supports their sexually indifferent nature. Furthermore, the basement membranes of the differentiating gonadal cords in both sexes have common features, which differ, however, from those of the other developing urogenital organs. Changes in carbohydrate composition appear with the sexual differentiation of the gonads; the similarity of the changes in lectin binding to the gonadal cords of embryonic and fetal male, and to postnatal female, suggests similar mechanisms of cell-cell interactions in both sexes although activated at different developmental stages. These carbohydrate specificities at the tissue level should be taken into account together with cell-type specific changes, e.g. in the formation of the zona pellucida, when the phenomenon of polymorphic expression of different compounds is integrated into theories of epithelial differentiation.

Intermediate filaments and epithelial differentiation of male rat embryonic gonad

The presence and distribution of desmin, vimentin, cytokeratin, and laminin in the gonads of developing male rat embryos (11-17 days) were studied by immunocytochemistry. The findings were correlated with morphological changes of the cells and with the formation of basement membranes, as determined by electron microscopy. The surface epithelial and subepithelial cells of the meesonephros in the prospective gonadal region contained desmin. At the onset of gonadal development, vimentin appeared in the somatic cells of the thickening surface epithelium, which formed the gonadal ridge. Desmin disappeared and cytokeratins appeared in the Sertoli precursor cells at the inception of their epithelial differentiation. Simultaneously, the prospective Sertoli cells became polarized during their assembly into epithelial cell aggregates; the aggregates then fused and formed elongated testicular cords. The epithelial cell differentiation was accompanied by a deposition of basement membrane material around the cords and by an increase of desmin in the cells immediately around the cords. With further differentiation of the testicular cords, some cytokeratins from the Sertoli cells, but not from the cells of the rete cords, disappeared. On the other hand, other cytokeratin polypeptides and vimentin remained in the fetal Sertoli cells. The surface cell layer slowly differentiated towards a proper epithelium after the basic formation of the testicular cords and interstitium. Desmin and vimentin persisted in the interstitial cells throughout the entire study period. The early differentiation of the gonad is apparently under a general sex-independent initiation program. The developmental changes in intermediate filaments offer an opportunity for the further analysis of their general role in early organogenesis. In light of the genetic theory of testicular differentiation, the functions of the regulatory factor(s) include specific organization of cord cells, histological organization into looping cords rather than separated follicles, and male development of the interstitium, surface epithelium and tunica albuginea.

Differentiation of smooth muscle cells in the fetal rat testis and ovary: localization of alkaline phosphatase, smooth muscle myosin, F-actin, and desmin

The histochemical demonstration of alkaline phosphatase (AP) activity and localization of smooth muscle myosin (SMM), F-actin, and desmin were carried out on frozen sections of testes and ovaries from 15-day-old fetal to newborn rats. The presence of immunocytochemically localized SMM and desmin was confirmed by Western blot analysis of proteins from isolated gonads. The development of smooth muscle cells was predominant in the testis. The first SMM-positive cells with an increasing intensity for F-actin and desmin appeared in the testicular tunica albuginea and around the testicular cords by the age of 16 days. A continuous layer of SMM- and F-actin-positive (but not uniformly desmin-positive) myoid cells was detected in the newborn testis. In the early gonads and in the newborn ovary, a majority of the interstitial cells expressed desmin, indicating that, in undifferentiated tissues, non-myogenic cells may also express desmin. During fetal development, male and female gonocytes showed a decrease in F-actin content but retained their high AP activity. In the cortex of the newborn rat ovary, the observed high AP activity and the presence of desmin may be associated with the postnatal histogenesis of the follicles. The presence of SMM-containing cells in the hilus of the ovary may be required for the demarcation of the ovary from the mesonephros by the constriction of the mesovarium. The occurrence of SMM-positive cells predominantly in male fetuses suggests that the development of the contractile cells in the fetal testis may be induced by testicular androgens.

Androgen synthesis in human fetal testis exposed in utero to a combination of norethindrone acetate and ethinyl estradiol

The effect of norethindrone acetate (NET-Ac) and ethinyl estradiol (EE2) on the 3 beta-hydroxysteroid dehydrogenase (HSD)-delta5-isomerase complex of the human fetal testis was studied by administration of 20 mg NET-Ac and 0.04 mg EE2 p.o on a single day to 4 women, pregnant 10-16 weeks, before abortion was induced, the other 4 patients serving as controls. Testosterone and androstenedione formation from radioactive dehydroepiandrosterone was measured in 8 fetuses by incubation of testicular tissue in vitro. The presence of normal feta Leydig cells was confirmed by electron microscopy. There was no difference between the enzyme activities of testicles in the experimental and control groups. The findins give values of 3 beta-HSD-isomerase activity in human fetal testis and suggest that the steroidogenic function of the fetal testis exposed for a short time to normally used contraceptive steroids remains at the same magnitude.

Nurse cells of the bursa of Fabricius: do they exist?

Cell-cell interactions in B lymphocyte development have so far been incompletely characterized, mostly due to lack of a special organ for B cell maturation in the mammalian species. Certain well-known lymphostromal interactions in the thymus have raised the question whether similar interactions with nurse cells would also operate in the development of B cells. We have tested this hypothesis in the chicken bursa of Fabricius, an organ specific for the B cell maturation. To identify possible nurse cells, with viable lymphocytes enclosed, the cells in the bursa of Fabricius were dispersed with collagenase and trypsin. Light and electron microscopic examination of bursa cell suspensions showed four types of aggregates, identified by low magnification light microscopy as potential nurse cell-like complexes. Electron microscopy revealed that all aggregates consisted of epithelial cells, and complexes of epithelial cells with lymphocytes enclosed were not observed. These findings indicate that interactions similar to those seen in the avian and mammalian thymus between epithelial nurse cells and T lymphocytes are not a part of the avian B cell differentiation process.

Developmental stages of fetal-type Leydig cells in prepubertal rats

Fetal Leydig cells were studied in rats during and after the perinatal-neonatal period by comparing changes in morphology, number and volume with changes in testicular steroids and serum luteinizing hormone (LH) concentration. Stereologic examination indicated regression of fetal Leydig cells in testis by showing that their total volume as well as the average cell volume decreased between prenatal day 20 and postnatal day 3. The total number and total volume of cells both increased between postnatal days 3 and 11 but the average cell volume did not change during the same time period. Determination of serum LH showed a close correlation between an increase in LH concentration and increases in total number and volume of cells. The combined number of fetal- and adult-type Leydig cells on day 20 was more than 20 times the number of fetal cells at 3 days of age. Electron microscopic analysis showed that fetal Leydig cells after birth formed conspicuous clusters, which were surrounded by a layer of envelope cells and extracellular material. Occasional dividing fetal Leydig cells and possible precursors of fetal or adult Leydig cells were observed. Mitoses of spindle-shaped pericordal cells were frequent during the neonatal period. During and after the second postnatal week fetal Leydig cells again showed signs of regression, indicated by disintegration of the cell clusters, a decrease in cell size, accumulation of collagen between the cells and a decrease in steroid content per cell.(ABSTRACT TRUNCATED AT 250 WORDS)

Transplantation of newborn rat testis under the kidney capsule of adult host as a model to study the structure and function of Leydig cells

Newborn rat testis was transplanted under the kidney capsule of adult castrated and uncastrated male rats to develop and characterize a model system for studies on Leydig cell development. Two weeks after transplantation, the number of Leydig cells and the size of their nuclei in the transplants had increased. Secretion of testosterone was indicated by increased seminal vesicle weights and decreased pituitary LH in the castrated host animals. Pituitary FSH content increased significantly in the uncastrated animals with transplants, which suggested production of an FSH-stimulating factor. Cells with the morphologic features characteristic of fetal- and adult-type Leydig cells were observed in the transplants. The seminiferous tubules with spermatocytes, incipient lumina, and significantly larger average diameters showed more advanced development than those in the normal 2-week-old testis. By the present morphologic and functional criteria, the kidney subcapsular transplantation technique provides a suitable model for studies of fetal and adult Leydig cell development.