Distribution of calcitonin-containing cells in the human thyroid

Human thyroid glands obtained within 2.5 hours of death were examined for the presence and distribution of calcitonin-containing cells using horseradish peroxidase as an indicator in an indirect immunohistochemical procedure. The glands were cut into 10 to 20 transverse slices per lobe and fixed in glutaraldehyde. A representative section of each paraffin-embedded slice was processed and systematically scanned for calcitonin-containing cells. Of 13 glands examined, ten contained calcitonin cells. The cells were found mostly in the follicular epithelium both singly and in groups. They were most numerous in the central region of each lobe of the gland. The isthmus and poles were devoid of calcitonin cells and only occasionally were these cells found at the surface. Parathyroid glands were examined by the same procedure for the presence of calcitonin cells but none were observed. These results demonstrate that calcitonin-containing cells are found regularly in human thyroid glands and that the distribution of these cells is centered in the central region of each lobe of the gland.     

An immunohistochemical study of calcitonin-containing cells in benign and malignant thyroid lesions

Parafollicular cells (C-cells) in benign and malignant thyroid lesions were studied immunohistochemically with a polyclonal anti-calcitonin (CT) antibody. The C-cells were seen most frequently in the middle third of the lateral lobes in the thyroid gland of normal individuals and patients with Graves' disease and chronic thyroiditis, although in the latter the number of such cells was significantly decreased (p less than 0.05). In adenomatous goiter, C-cells were present in nodular lesions from an early stage of nodule development (frequency about 19%), whereas in the later stage these cells were rarely observed inside type 1 nodules, which were generally characterized by an admixture of follicles with considerably different sizes. However, C-cells were not observed inside type 2 nodules, which were composed of similar-sized follicles, or in the parenchyma of 56 cases of benign and malignant thyroid tumors. These findings suggest that since C-cells are present in nodular lesions, the histogenesis of adenomatous goiter is quite different from that of follicular adenoma; thyroid neoplasms generally contain no C-cells in the parenchyma.     

Decrease in calcitonin-containing cells in truncus arteriosus

Experimental studies in chick embryos have demonstrated that truncus arteriosus (TA), a form of conotruncal cardiac defect, is due to abnormalities in the cranial neural crest. However, no data are available to support this hypothesis in humans with isolated TA. In the present study, the assessment of calcitonin immunoreactive cells (C-cells) has been employed to evaluate whether or not the proportion of thyroid cells derived from the cranial neural crest is normal in patients with isolated TA. Thyroid sections from 15 such patients in which no other extracardiac malformations were neither clinically nor pathologically found, and from 11 control age-matched patients were studied immunohistochemically at autopsy in order to determine the number and distribution of calcitonin-containing cells. The volume density of C-cells (0.888%) and the number of C-cells per follicle (0.991) was significantly lower in patients with TA than in control patients (3.475%, and 2.367, respectively). The decrease of neural crestderived cells in the thyroid of patients with “isolated” TA documents more extent abnormalities than clinically suspected and supports the hypothesis of neural crest disturbance as the pathogenetic factor responsible for this heart malformation. © 1993 Wiley-Liss, Inc.     

The early development of the median thyroid gland of the mouse

Summary The mesobranchial area and the median thyroid anlage of embryonic albino mice were investigated from the somite stage 4 to 40 (81/2–10 days of gestation). In stage I (5–25 somites), there is an unequal growth and differentiation of the epithelium in the floor of the pharynx, whereby a mesobranchial area with a stratified or pseudostratified epithelium is formed. This area is distinct from the remaining pharyngeal epithelium, among other things by an apical microfilament system in the superficial epithelial cells. It is found just basal to a row of plump cytoplasmic protrusions, which extend into the lumen of the pharynx. In stage II (26–40 somites), the cranial part (median thyroid anlage) of the mesobranchial area thickens in relation to the caudal part and grows down into the underlying mesenchyme. The filament system is concentrated in the superficial cell layer of the median thyroid anlage at the beginning of stage II and disappears during downgrowth.In both stages, but most pronounced in stage II, there is a population of 0.1–5 intracellular bodies, which occasionally contain the remains of organelles. The larger bodies, which often contain the remains of nuclei, are usually found peripherally while the smaller ones are more evenly distributed. Acid phosphatase can often be demonstrated histochemically in small bodies, while larger bodies are usually without reaction. Cells with pycnotic nuclei and/or degenerated cytoplasmic components are regularly found. Acid phosphatase can also be demonstrated in Golgi complexes and surrounding vesicles. Basal to the epithelium, bodies are occasionally found which may possibly have been extruded from that tissue.This work was supported by a grant (A 1/65) from Danish Medical Research Coucil.     

Determination of avidity of anti-albumin antibodies in the mouse: Influence of the number of cells transferred on the quality of the secondary adoptive response

We observed that the volume of any anti-HSA serum needed to bind 50 per cent of the antigen is a linear function of the amount of antigen present in the reaction mixture over three log units. The slope is characteristic of each antiserum and reflects the `avidity' of the antibodies.

By using this quantitative index we found that the avidity of antibodies produced during the secondary adoptive response depends on the number of the cells transferred: few cells will produce antibodies of lower avidity than many cells. The dose of antigen given as a booster also influences the quality of the antibody produced; in the extreme case where some primed cells were rendered `tolerant' by supra-optimal doses of challenging antigen, substantial amounts of low avidity antibodies were synthesized. The results can be explained by competition for antigen among competent cells, favouring those cells which carry antibody sites with high affinity for the corresponding antigenic determinant.

     

Chromosome number and development of artificial mouse oocytes and zygotes

BACKGROUND: Infertility due to the absence of gametes is one of the last frontiers in reproductive medicine. Sperm or oocyte donation is currently the only treatment option but this approach lacks the genetic contribution of both partners. Artificial production of gametes through haploidization may offer an alternative strategy. The aim of this study was to evaluate the efficiency of producing artificial oocytes and zygotes with correct chromosome number. METHODS AND RESULTS: Somatic cumulus cell nuclei were injected into non-enucleated oocytes to produce artificial zygotes and into enucleated mature mouse oocytes to produce artificial oocytes. The expected chromosome number of artificial zygotes and oocytes is 40 and 20 chromosomes respectively. Fertilization and developmental potential of artificial zygotes and oocytes inseminated by IVF or ICSI were investigated. The expected chromosome numbers were found in 12% of artificial zygotes and 15% of artificial oocytes. Varying the time interval between injection of the somatic nucleus and activation (3, 5, 8 h) tended to increase the efficiency up to 18 and 23% for zygotes and oocytes respectively. Two-cell formation rates were 90% for artificial zygotes and 37% for artificial oocytes after IVF and 53% for artificial oocytes after ICSI. Blastocyst formation rates were 15, 8 and 9% respectively. CONCLUSIONS: Chromosome number analysis shows that the efficiency of obtaining artificial zygotes and oocytes with correct chromosome number was low and that developmental potential was severely hampered. These observations question the possibility of obtaining chromosomally normal embryos from artificial oocytes or zygotes.     

Changes in the number of stem cells during cultivation of mouse bone marrow on a bed of fibroblast-like cells

The number of colonies was counted in the spleen of irradiated mice after injection of a culture of mouse bone marrow cells. The colony-forming units were found to persist in the culture only for a short time. The use of a previously grown bed of fibroblasts of bone-marrow origin did not affect the preservation of the colony-forming units or the dynamics of the change in their number.Laboratory of Histogenesis, Institute of Developmental Biology, Academy of Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A.P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 6, pp. 718–719, June, 1976.     

Effect of the number of inseminated spermatozoa on subsequent human and mouse embryonic development in vitro.

It has been shown, in both human and mouse in-vitro fertilization (IVF), that an excess number of spermatozoa in the insemination medium leads to reduced fertilization rates. In this study, we evaluated human embryonic development after dividing the oocytes of each of 62 IVF attempts into two groups on the basis of insemination with two widely used concentrations (50,000 and 100,000 spermatozoa/ml). The embryonic growth was retarded in the group inseminated with 100,000 spermatozoa/ml: significantly fewer fast developing embryos (4-cell and 5- to 8-cell stages) were found (53.4% in the 100,000/ml group and 65.5% in the 50,000 group; P less than 0.05). In two experimental series, mouse embryonic development was evaluated in the presence of 0, 50,000, 100,000 and 500,000 spermatozoa per ml. In the first series, the spermatozoa were present during 5-20 h after insemination, while in the second series, the spermatozoa were present during the whole culture period of 120 h. The development of mouse embryos was impaired when 500,000/ml spermatozoa were present during the whole culture period. In contrast with human IVF results, the presence of up to 500,000 spermatozoa during the first 20 h after insemination did not have any significant detrimental effect on blastocyst formation in the mouse.     

Syngeneic sensitization of mouse lymphocytes on monolayers of thyroid epithelial cells:

The determination of the frequency of normal spleen cell involvement in Primary syngeneic sensitization (PSS) against thyroid epithelial cells (TEC) was performed using the limiting dilution analysis. It was found that their frequency, which reaches 1:5440, is related to the expression of major histocompatibility complex (MHC) antigens (K end or D end) and of the specific antigen thyroglobulin (Tg) exposed on the surface of the TEC monolayer. Moreover, a significant diminution of this frequency was obtained by the addition of 25% normal syngeneic lymph node (LN) cells.     

Influence of age on size and number of fat cells in the epididymal depot.

The extensive literature on the effect of rat age on the size and number of adipocytes in adipose tissue depots relates solely to young developing rats and young adults. Therefore a study was carried out in our laboratory on the cellular characteristics of the epididymal depot of the Fisher 344 strain of rats through virtually the entire life-span. Collagenase digests of this depot prepared from rats of 9, 13, 26, 52, 104, and 130 wk of age yield a population of cells with diameters greater than 30 mum identified as adipocytes or "fat cells." A remarkably complex pattern of changes in both the size and the number of these fat cells in the epididymal depot occurred through the life-span of the rats. The epididymal depots also contain some cells with diameters around 10 mum which have a morphology similar to that of the classic adipocytes; such cells may be preadipocytes.     

Changes in lectin-binding sites on epididymal cells during postnatal development of the mouse

Using lectin histochemistry combined with immunohistochemistry, we recently demonstrated that the principal, clear, and basal cells in the adult mouse epididymis specifically react with UEA-I, MAL-I, and GS-IB lectins, respectively. The present study examined the distribution of the lectin-binding sites for some lectins on the epididymal epithelium during postnatal development. Galactose staining with GS-IB was first detected in some of the undifferentiated epithelial cells in mice aged 1 week, and this characteristic became specific to basal cells in mice aged 2 weeks and above. Fucose staining with UEA-I was first detected in the principal cells in mice aged 3 weeks. Staining of sialic acid with MAL-I was first detected in all undifferentiated epithelial cells in mice aged 1 week, and this characteristic became specific to the narrow and clear cells in all regions and to the principal cells in regions IV and V in mice aged 3 weeks. The results indicate that epididymal differentiation is characterized by the expression of cell- and region-specific sugar chains that appear early during postnatal development before the sperm arrives in the epididymis.     

Effect of poly-4-vinylpyridine on the number of colony-forming cells in mouse bone marrow and spleen

Injection of poly-4-vinylpyridine in the maximal tolerated dose into mice doubles the number of colony-forming units (CFU) in the bone marrow and reduces the number of nucleated cells by 22%. The increase in the CFU pool takes place from the second through the seventh day. The number of bone marrow cells starts to decrease 2 h after injection of the polymer and remains below the initial level for 5 days; after the second day, however, it starts to return gradually to normal, which it reaches by the seventh day. The number of CFU in the spleen increases ninefold, and this is accompanied by the development of marked splenomegaly on account of the increase in the number of cells.(Presented by Academician of the Academy of Medical Sciences of the USSR P. D. Gorizontov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 4, pp. 474–476, April, 1977.     

Influence of preincubation on the development of the inhibition of protein synthesis in extracts from interferon-treated mouse L cells. Action on tRNA.

Treatment of cells with interferon leads to an inhibition of cell-free protein synthesis in preincubated cell extracts. We show here that the observation of such a defect in the translation of both Mengo virus RNA and poly(U,C) depends critically upon the length of preincubation period. Control and interferon-treated cell extracts (Cont. S-10, Int. S-10) preincubated for up to 60 min have identical protein synthetic activity when assayed with either Mengo virus RNA or poly(U,C). Although preincubation of Cont. S-10 for more than 60 min leads to a gradual reduction in the protein synthetic capacity of the extract, the activity of Int. S-10 declines much more rapidly, and after 60 to 120 min of preincubation the translational activity of Int. S-10 is markedly inhibited (80–90%) compared to Cont. S-10. In extracts preincubated for times sufficient to allow the development of this impaired protein synthesis, addition of both total tRNA and a purified leucine tRNA restores synthesis by Int. S-10 to almost the same level as the corresponding controls. Addition of total tRNA, but not leucine tRNA, also overcomes the loss of activity observed in Cont. S-10 extracts which have been preincubated for more than 60 min. Addition of leucine tRNA to Int. S-10 during the preincubation step strongly reduces the ability of the tRNA to restore protein synthesis. Int. S-10 programmed with Mengo virus RNA synthesized the same polypeptides as Cont. S-10 when the preincubation period was 60 min or less. Although preincubation of Cont. S-10 for more than 60 min led to a decline in their activity, the pattern of polypeptides synthesized was not affected. However, preincubation of Int. S-10 for more than 60 min caused a decrease in the size of polypeptides as well as a reduction in their amount. Only peptides of MW 7000 to 26,000, were detected in such extracts. Addition of tRNA to the Int. S-10 restored the synthesis of larger polypeptides in a dose-dependent fashion and, with suitable amounts of total tRNA, the pattern of polypeptides synthesized was identical to that for control extracts. Our results indicate that preincubation of cell-free extracts leads to a decline in their capacity to utilize tRNA and that pretreatment of the cells with interferon strongly enhances this effect, at least with respect to leucine tRNA. The inability of extracts prepared from interferon-treated cells to utilize endogenous tRNA after prolonged preincubation (60–120 min) is most probably due to inactivation of the tRNA.     

Effects of microflora on the neonatal development of gut mucosal T cells and myeloid cells in the mouse

Colonization with commensal flora in very early life may profoundly influence intestinal lymphoid development and bias later immune responses. We defined gut-homing T cell phenotypes and the influence of flora on intestinal immune development in mice. Intestinal T cells were phenotyped and quantified in conventional (CV), germfree (GF) and conventionalized germfree (GF/CV) neonatal mice by immunohistochemistry. Mucosal adressin cell adhesion molecule 1 (MAdCAM-1) was expressed by mucosal vessels at birth in CV and GF mice and was more prevalent in CV than GF small intestine, but was distributed similarly and did not change with age. Less MAdCAM-1 was expressed in the colon; its distribution became restricted after weaning, with no difference between CV and GF mice. CD3(+)beta(7) (+) cells were present in similar numbers in CV and GF intestine at birth. They were CD62L(-) in CV mice and were accompanied by further CD3(+)beta(7) (+)CD62L(-) T cells as development progressed, but in GF and GF/CV intestine they expressed CD62L and numbers did not change. IEL numbers increased at weaning in CV mice in both small and large intestine, but showed delayed development in GF intestine. Macrophages were present at high levels from birth in GF intestine, but dendritic cells did not develop until day 16. Thus, fetus-derived T cells seed the intestinal lamina propria before birth via beta-MadCAM interactions. Their activation status depends on the microbiological status of the dam, and without a commensal flora they remain naive. We propose that these cells regulate antigen responsiveness of the developing mucosal T cell pool.     

Peripheral development of B cells in mouse and man

Summary:  In man and in mouse, B-cell maturation occurs in steps, first in the bone marrow from hematopoietic precursors to immature/transitional B cells, then in the periphery from transitional to fully mature B cells. Each developmental step is tightly controlled by the expression and function of the B-cell receptor (BCR) and by the ability to interact with the microenvironment. Mature B cells collaborate with T cells in the adaptive immune response, leading to the production of high-affinity antibodies. This response is very accurate, but slow. Immediately after pathogen entry, however, antibodies already present in the serum reinforce the innate immune response and contribute to the first-line defense against infection. Low-affinity natural antibodies are produced by B-1a B cells in the mouse and immunoglobulin M (IgM) memory cells in man. These antibodies represent an immediate protection against all microorganisms and the only one against encapsulated bacteria. B-1a and IgM memory B cells may function as a link between the innate and adaptive immune response and thus perform a primordial B-cell function.