Lorenz Revisited

Certain characteristics of childhood immaturity (e.g., infantile facial features) may have been favored by natural selection to evoke positive feelings in adults. We propose that some aspects of cognitive immaturity might also endear young children to adults. In two studies, adults rated expressions of mature and immature thinking attributed to children. Immature thinking in which children expressed a supernatural explanation elicited positive affect reactions, whereas other forms of immature thinking, which made no attribution to supernatural causation, were responded to negatively. This pattern was found for parents and others, males and females, American and Spanish college students, and for target children 3 to 9 years of age. We suggest that persistence of supernatural thinking in adulthood causes people to view the expressions of such thinking in children in a positive manner, fostering nurturance of young children who display them.     

"C"-shaped canal configuration of mandibular second permanent molar

Roots of the second mandibular molar often fuse so the purpose of this investigation was to examine the appearance of "C"-shaped root canals and to classify different root canal types. A hundred and twelve randomly chosen second lower permanent molars-after extraction due to periodontal disease-were prepared and then analysed. Contrast liquid (methylene blue) was injected into prepared teeth. Each tooth was cut into slices to view the root canal morphology. Results of the analysis revealed fusion, either total or partial in 14 cases (12.5%). As a conclusion various appearances were classified into 5 types according to the fused canal shapes and the frequency of different types varied from 0.89%-6.25%.     

Harderian gland: regulation of sexual "type" by gonads and pineal gland

The sexual dimorphism of the Harderian glands of golden hamsters is regulated by a complex interaction of the gonads and pineal gland. Ovariectomy was shown to prevent the conversion to male-type gland which normally follows blinding. Testosterone administration in combination with blinding and ovariectomy promoted the male type. Ovariectomy after 8 wk of blinding was ineffective in reversing the effects of blinding on the Harderian glands, but ovariectomy and pinealectomy caused complete reconversion to the female type. To our knowledge, this is the first report to demonstrate an influence of the ovaries on the Harderian gland of the hamster. In males, administration of testosterone for 7 days after 8 wk of castration was shown to have little effect on the conversion to the female type which normally attends castration, whereas testosterone injection followed by a period of blinding completely reversed the effects of castration on the Harderian gland. These studies, along with previously published reports, strongly suggest that the male-type Harderian gland is expressed whenever significant androgen levels are present, or when the glands are exposed to androgen priming during or just prior to a period of blinding-induced pineal activation. The probable role of ovarian androgens in mediating conversion to the male-type gland is discussed.     

"Light" and "dark" pinealocytes of the porcine pineal gland

Both qualitative and quantitative comparative studies of "dark" and "light" pinealocytes of the porcine pineal gland have been carried out. These cells differ from each other in their electronic density of cytoplasm, shape of nucleus, the structure of membrane bound dense bodies and the number of microtubules and smooth endoplasmic reticulum. The membrane bound dense bodies--characteristic structures of pig pinealocytes as well dense core vesicles occur in both types of cells. The relative volume of the majority of the cells' organellae apart from the Golgi apparatus, also do not show any significant difference. The results obtained support a functional basis for pinealocyte differentiation in the porcine pineal gland.     

A "virtual gland" method for quantifying epithelial fluid secretion

We developed a new apparatus, the virtual gland (VG), for measuring the rate of fluid secretion (Jv), its composition, and the transepithelial potential (TEP) in cultured epithelial cells under open circuit. The VG creates a 10-microl chamber above the apical surface of epithelial cells on a Costar filter with a small hole leading to an oil-filled reservoir. After the chamber is primed with a fluid of choice, secreted fluid is forced through the hole into the oil, where it forms a bubble that is monitored optically to determine Jv and collected for analysis. Calu-3 cells were mounted in the VG with a basolateral bath consisting of Krebs-Ringer bicarbonate buffer at 37 degrees C. Basal Jv was 2.7 +/- 0.1 microl x cm(-2) x h(-1) (n = 42), and TEP was -9.2 +/- 0.6 mV (n = 33); both measures were reduced to zero by ouabain (n = 6) x Jv and TEP were stimulated 64 and 59%, respectively, by 5 microM forskolin (n = 10), 173 and 101% by 1 mM 1-ethyl-2-benzimidazolinone (n = 5), 213 and 122% by 333 nM thapsigargin (n = 5), and 520 and 240% by forskolin + thapsigargin (n = 6). Basal Jv and TEP were inhibited to 82 and 63%, respectively, with 10 microM bumetanide (n = 5), 71 and 82% with 100 microM acetazolamide (n = 5), and 47 and 56% with 600 microM glibenclamide (n = 4). Basal Jv and TEP were 52 and 89% of control values, respectively, after HCO3- replacement with HEPES (n = 16). The net HCO3- concentration of the secreted fluid was close to that of the bath (25 mM), except when stimulated with forskolin or VIP, when it increased (approximately 80 mM). These results validate the use of the VG apparatus and provide the first direct measures of Jv in Calu-3 cells.     

Inner enamel epithelia synthesize and secrete enamel proteins during mouse molar occlusal "enamel-free area" development

Mesenchyme-derived instructions for odontogenic epithelial differentiation into ameloblasts and the production of enamel matrix has been well established. However, it is not known how position-specific differences within the enamel organ of rodent molar tooth organs regulate the enamel-forming vs. the enamel free areas in the developing cusp. Light microscopy, transmission electron microscopy, and immunocytochemistry using a rabbit anti-mouse amelogenin antibody, were used to map the position-specific patterns within the enamel organ. In the enamel-forming area, ameloblasts were associated with stratum intermedium. In the enamel-free area, another cell type was interposed between inner enamel epithelia (IEE) and stratum intermedium. IEE in the enamel-free area did not have Tomes' processes and secreted enamel matrix not only toward dentin but also between IEE cells. IEE became confluent with stellate reticulum; at this position stratum intermedium cells were no longer detected. The thickness and orientation of dentin matrix collagen fibers in the enamel-free area were different from the fibers in the enamel-forming area. These results suggest that the patterns of epithelial cell-cell and cell-matrix associations during position-specific enamel organ epithelial differentiation may regulate ameloblast matrix synthesis and/or the matrix secretion pathway.     

Prenatal development of "synaptic" ribbons in the guinea pig pineal gland

Pineal "synaptic" ribbons are a heterogeneous population of organelles. "Synaptic" ribbons (SR) sensu stricto, "synaptic" spherules (SS), and intermediate forms (IMF) are present. Their function and origin are unknown, and a knowledge of their prenatal development is lacking. Thus the pineal glands of prenatal, neonatal, and adult guinea pigs were prepared for electron microscopy. "Synaptic" ribbons were studied morphologically and quantitatively. The three categories of "synaptic" ribbons reported in adult pineal glands were also present in prenatal pineal glands. Their structural features, distribution, grouping, and composition patterns are similar to those in adults. "Synaptic" ribbons were first detected in pinealocytes of the distal region of a 42-day postcoitus (PC) pineal gland and were comparable with those in adults. They increased in number with age and reached a peak at 63 days PC, followed by a steep decline at 66 and 67 days PC. By day 69 PC, the numbers increased again and showed a dramatic increase after birth. Several true ribbon synapses were seen at day 63 PC between pinealocyte cell processes or between pinealocyte cell process and pinealocyte cell body. Since true ribbon synapses have not been found in adult guinea pig pinealocytes, their synaptic nature could have been lost during development. No precursors for the "synaptic" ribbons were found. The endoplasmic reticulum cisternae may be the origin for the ribbon vesicles because of their close association with the "synaptic" ribbons.     

A "20K" form of growth hormone in the murine pituitary gland

Extracts of mouse and rat adenohypophyses have been analyzed for a low-molecular-weight variant of growth hormone (GH) known to occur in humans, the so-called "20K"-GH (mol wt = 20,000 vs 22,000 for traditional human GH). Pituitary proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunostained with an antiserum raised against murine GH. Reactive and unreactive bands in close vicinity of the major GH band were fingerprinted by a peptide-mapping technique that reveals only the tyrosine-containing peptides, but can be applied to fingerprint single protein bands within gels. We found a protein band 2000 mol wt smaller than the major murine GH in both mouse and rat pituitary glands whose fingerprint resembled that of major GH. The peptide-mapping results are consistent with the interpretation that the internal deletion of amino acid residues most likely is in the same region of the molecule as in the human 20K-GH. Unlike the human 20K-GH, however, the murine counterpart showed no cross-reactivity with an antiserum raised against 22K-GH in the test system used here.     

Computer faces: the human Lorenz matrix

Realistic Ekman-type faces were generated by a computer program. Twenty primary parameters (muscle tensions and opening factors), each continuous, were used. Non-linear combination of the primary parameters permits the generation of meaningful faces each governed by a single combined parameter (intensity-parameter). Five major meaningful faces were distinguished, "friendliness", "surprise", "disgust", "anger" and "grief". In contrast to the experiments of Ekman, who combined subregions of photographed meaningful faces by hand, mixing can be done in the computer both more easily and, it turns out, more naturally. Mixed facial expressions in an animal were first drawn in matrix form by Lorenz. A consistent interpretation is possible if the linearly superposed displays are assumed to indicate the state of an autonomous optimizer with n linearly independent subfunctionals. An instant display of a vector in n-dimensional space using faces was already proposed by Chernoff. The present faces have the asset that only "natural" parameters are used. This means that no longer only a single point in n-dimensional space can be displayed, but also a meaningful succession of such points--that is, a whole trajectory.     

Electron microscopic observations of the anterior pituitary gland. Part I. The neurons in the "transitional zone" of the anterior pituitary gland

Since [Westlud, K.N., Chils, G.V., 1982. Localization of serotonin fibers in the rat adenohypophysis. Endocrinology 111, 1761-1763] initially identified the serotonin nerve fibers in the anterior pituitary gland, attention has been paid to the rostral zone of the anterior lobe into which nerve fibers enter and subsequently spread to deeper regions of the lobe. The rostral zone is the trifurcated junction of the partes tuberalis, intermedia and distalis, and has the important role(s) for hormone secretion via the "transitional zone" [Sato, G, Shirasawa, N, Sakuma, E, Sato, Y, Asai, Y, Wada, I, Horiuchi, O, Sakamoto, A, Herbert, DC, Soji, T, 2005a. Intercellular communications within the rat anterior pituitary. XI: An immunohistochemical study of distributions of S-100 positive cells in the anterior pituitary of the rat. Tissue and Cell 37, 269-280.]. The objective of this study was to focus on the ultrastructure of this "zone." All of the animals studied were fixed by perfusion with glutaraldehyde via the left ventricle of the heart and examined by electron microscopy. In the "transitional zone," a cluster of neuronal elements was observed between the folliculo-stellate cell-rich area and the anterior lobe. This cluster consisted of myelinated fibers, unmyelinated fibers, neuroendocrine fibers, large cells, and supporting cells. The large cells were perikarya of neurons which made a "ganglion-like" structure with associated satellite cells. Agranular, folliculo-stellate cells were intermingled among the elements. This is the first report that neuronal elements form clusters in the "transitional zone." A relationship of the unmyelinated and neuroendocrine fibers in the basal layer and in the "transitional zone" is discussed.     

Postnatal development of "synaptic" ribbons and spherules in the guinea pig pineal gland

Previous studies have shown that the functionally enigmatic pineal "synaptic" ribbons are structurally a heterogeneous group of organelles consisting of rodlike ribbons sensu stricto, spherules, and intermediate forms. As ribbons and spherules react differently under various experimental conditions, these organelles were studied qualitatively and quantitatively during the postnatal period in guinea pigs. It was found that the pinealocytes were highly differentiated at birth and contained all three forms of "synaptic" structures. Ribbons and intermediate forms were more abundant than spherules and exhibited a striking increase in number on postnatal days 1 and 2; this increase was followed by a distinct trough and by a second peak at days 12 and 13, after which their numbers declined to reach adult levels by day 20. The spherules were small in number at birth and did not show the large immediate postnatal increase observed for the ribbons and intermediate forms. Instead there was a steady numerical increase up to day 12 (absolute number) or day 15 (relative numbers), followed by a decrease to adult level by day 20. Whereas during the early postnatal period (days 1 to 3) the majority of pinealocytes were characterized by ribbons and intermediate forms, with increasing age spherule-bearing pinealocytes increased in number. As ribbons and spherules were usually not found in the same pinealocyte, the present findings are interpreted to mean that ribbons and spherules characterize different types of pinealocytes showing an inverse numerical development postnatally. Developmentally intermediate forms behave like ribbons.