Monitoring of cell layer coverage and differentiation with the organic electrochemical transistor

High resolution monitoring of cell layer integrity with the OECT was up until now, limited to high resistance, barrier tissue type cells. In this work, the sensitivity and versatility of the device is expanded to monitor all adherent cell types.

Organization of prenatal care in Belgium

Prenatal care in Belgium is characterized by regional variations between the Flemish- and French-speaking communities. Generally, care in the former area is provided by a general practitioner or a gynecologist/obstetrician in private practice, and in the latter by a gynecologist/obstetrician on a private or public basis. The level of use of prenatal care observed is, on average, high, but variations do exist according to the socioeconomic and cultural characteristics of the families and the health care services which they frequent.

Fast neutron yields and spectra from targets of varying atomic number bombarded with deuterons from 16 to 50 MeV

Neutron production from targets of Be, C, Mo, Cu, Ta and Au bombarded with deuterons of 16, 33 and 50 MeV has been studied at the isochronous cyclotron at Louvain-la-Neuve. Neutron spectra were measured by the time of flight method. The yields of neutrons and gamma rays were also measured, and the greatest ratio of neutrons to gamma rays in the forward direction was found to occur with 50 MeV deuterons on a Be target. The angular distribution of neutrons from Be was measured at 16, 33 and 50 MeV, and neutron spectra were measured as function of angle with 50 MeV deuterons on Be.

Immunohistochemical study of the human pituitary with anti-luteinizing hormone, anti-follicle stimulating hormone and anti-thyrotrophin sera

Sections of fixed human pituitaries were investigated by an indirect immunofluorescence technique using antisera obtained following immunization of rabbits with human chorionic gonadotrophin (HCG), human hypophyseal gonadotrophins (HHG) and bovine hypophyseal thyrotrophin (BTSH) preparations. After microphotography of immunofluorescent positive cells, the tissue sections were stained by the Alcian blue (or Thionine aldehyde)-Periodic Acid Schiff-Orange G method. The microscopical fields which had been examined in immunofluorescence were then relocated and photographed again. A correlation was established between the cells reacting with an antiserum and the cell types of the morphological nomenclatures for human adenohypophysis proposed by Romeis (1940) and by Pearse & van Noorden (1963) and those of the functional classification proposed by Herlant & Pasteels (1967).

The specificity of the antisera was checked by immunoelectrophoresis and by neutralization of the biological activities of luteinizing hormone (LH), follicle stimulating hormone (FSH) and BTSH. After selective absorption of the FSH neutralizing antibodies an anti-HCG serum became specific for LH. After selective absorption of the LH neutralizing antibodies an anti-HHG serum was found specific for FSH. The anti-BTSH sera neutralized the biological activity of human TSH, but cross reacted in immunoelectrophoresis with ovine LH and in immunofluorescence with the gonadotrophic cells of human pituitaries. After absorption with HCG, an anti-BTSH serum produced a specific immunofluorescence in large purple blue to dark blue Romeis δ cells filled with fine Alcian blue (or Thionine aldehyde) positive granules. This cell type is equivalent to the S2 mucoids of Pearse or to the "Thyrotrophs" of Herlant. The anti-LH and anti-FSH sera cross-reacted with TSH. Indeed, the S2 mucoids were also fluorescence positive with both anti-gonadotrophic sera. In addition, both anti-LH and anti-FSH sera produced a specific immunofluorescence in the group of purple coloured Romeis δ cells closely related to the S1 mucoids of Pearse. This would indicate that the same cell type contains immunoreactive LH and FSH, which is in contradiction with the description of two different gonadotrophic cell types based on histochemical stainings of human and animal pituitaries obtained in various physiopathological conditions.

Immunohistochemistry of individual adenohypophysial cells

Immunohistochemistry is the intracellular detection of antigens by the use of specific antibodies labelled with a tracer. The choice of the tracer is such that the sites of the antigen-antibody reactions can be visualized by microscopic examination. The present report refers to the human pituitary where most of the immunohistochemical identifications of adenohypophysial cells were conducted with antibodies specific of their hormonal content and labelled with fluorescein isothiocyanate as tracer. Such immunohistochemical identifications had to be correlated to the morphological nomenclatures of the glandular cells based on histochemical stainings. Confusion has been introduced in these nomenclatures by the definition of three to eight cell types using different criteria and different terminologies. In the present report, owing to this absence of standardization, the comparative evaluation of immunohistochemical data have been based on Romeis (1940) and Pearse & van Noorden (1963) nomenclatures.

There is strong experimental evidence supporting the localization of adrenocorticotrophic hormone (ACTH) in the basophils of Romeis β type (R-mucoids of Pearse). Somatotrophic hormone (STH) has been consistently found in the acidophils of Romeis a type. In the human, there is no direct evidence to support the localization of prolactin (LTH) in the acidophils of Romeis ε type. Luteinizing hormone (LH) and follicle stimulating hormone (FSH) have both been located in the basophils of Romeis δ type (S-mucoids of Pearse). Further investigations into the human and also into other mammalian species are required to determine if the gonadotrophic hormones have different localizations on the cellular or on the subcellular level. The immunohistochemical localizations of thyroid stimulating hormone (TSH) and melanocyte stimulating hormone (MSH) have not been convincingly achieved.

The conclusions drawn from immunohistochemical studies of the adenohypophysis are essentially limited by the cross reactions existing between STH and prolactin, between ACTH and MSH and between LH, FSH and TSH.

More experimental data on these immunological cross reactions are still required before more accurate morphological discriminations can be achieved between the cell types secreting STH and prolactin, between those secreting ACTH and MSH and between those secreting LH, FSH and TSH. In addition, when hormones of the adenohypophysis are chemically and/or antigenically closely related, the cells responsible for their secretion are morphologically very similar too.

Finally, immunohistochemical studies revealed the lack of species specificity of the pituitary hormones. Extensive cross reactions have been shown between human STH and STH of all mammalian species studied so far. Consistent cross reactions were also found between human gonadotrophins and those of several mammalian species.