Interactions between human and porcine interferons.

To investigate the possible interactions between human and porcine interferons (IFNs) in vitro, human transformed (FL) and nontransformed (HEF) cells were treated with either HuIFN alpha and/or gamma and porcine alpha and/or gamma. In both cases the antiproliferative activity was measured to determine the effects of different combinations between human and porcine IFNs on cell proliferation. Combinations of human and porcine IFNs acted mostly antagonistically with exception of IFN combination Hu-alpha/Po-gamma which showed a synergic cooperativity in therms of antiproliferative activity on human transformed cells.     

Dibasic staining of large epoxy tissue sections and applications to surgical pathology

A variety of normal and pathologic aldehyde-fixed osmium postfixed human tissues were prepared as large sections embedded in Spurr epoxy. They were stained with a sequential basic fuchsin--methylene blue stain which gives "hematoxylin- and eosin-like" staining and additionally functions as several special stains. This technic also allows for electron microscopy directly on the embedded tissue. The histologic and cytologic preservation and overall staining was superior to tissue embedded in glycol methacrylate. The methods and technics presented in this article have important applications in diagnostic surgical pathology and histology in general.     

New perspectives in breath-by-breath determination of alveolar gas exchange in humans

Alveolar gas transfer over a given breath (i) was determined in ten subjects at rest and during steady-state cycling at 60, 90 or 120 W as the sum of volume of gas transferred at the mouth plus the changes of the alveolar gas stores. This is given by the gas fraction (FA) change at constant volume plus the volume change (deltaVAi) at constant fraction i.e. VAi-1(FAi-FAi-1)+FAi x deltaVAi, where VAi-1 is the end-expiratory volume at the beginning of the breath. These quantities, except for VAi-1, can be measured on a single-breath (breath-by-breath) basis and VAi-1 set equal to the subject's functional residual capacity (FRC, Auchincloss model). Alternatively, the respiratory cycle can be defined as the interval elapsing between two equal expiratory gas fractions in two successive breaths (Gr?nlund model G). In this case, Ft1 = Ft2 and thus the term VAi-1 (FAi-FAi-1) vanishes. In the present study, average alveolar O2 uptake (VO2,A) and CO2 output (VCO2,A) were equal in both approaches whereby the mean signal-to-noise ratio (S/N) was 40% larger in G. Other approaches yield steady state S/N values equal to that obtained in G, although they are based on the questionable assumption that the inter-breath variability of alveolar gas transfer is minimal. It is concluded that the only promising approach for assessing "true" single-breath alveolar gas transfer is that originally proposed by Gr?nlund.     

Expression of herpesvirus thymidine kinase gene under control of early promoter of SV40

A 0.31-kilobase fragment of SV40 DNA containing the early promoter of this virus was isolated. The pX1 plasmid containing the herpesvirus thymidine kinase gene (TK) was cleaved with BglII and SalI to remove the TK promoter. The Sv40 DNA fragment was mixed with the TK gene without its promoter and blunt-end ligated after treatment with S₁ nuclease. The newly engineered plasmid was used for the transformation of TK-deficient LtA cells to TK⁺ phenotype. Blot hybridization experiments show that the plasmid is integrated into high-molecular-weight DNA in both of the transformed colonies that we have studied. Also the mRNA in these cells is a hybrid molecule containing both TK and SV40 sequences.     

Time course of hypo-osmotic swellings of human spermatozoa: evidence of ordered transition between swelling subtypes

The hypo-osmotic swelling test (HOST or HOS test) usually takes into consideration the total HOS response value with no emphasis either on the value of the response subtypes or the response evaluation time. This study investigated the time course of HOS responses and analysed their physiological relevance. Raw semen spermatozoa and Percoll washed spermatozoa were used in the experiment. The morphological changes in the sperm tail were monitored by incubating the spermatozoa in the hypo- osmotic solution for 16 different time periods. The HOS reactive spermatozoa and the type of HOS reaction (swelling subtypes) of the samples subjected to different duration of treatment were identified under a phase contrast microscope. Also the fate of individual spermatozoa in a hypo-osmotic environment were monitored for 30 min. In spermatozoa exposed to a hypo-osmotic solution, the motility lasted usually less than 2 min and motility characteristics were uniquely different from that of the spermatozoa under iso-osmotic conditions. The HOS response development was permanent but the motility loss due to hypo-osmotic shock was reversible up to 1 min of incubation. There was an indication of ordered transition among the HOS swelling subtypes apparently initiating with subtype b destined to c, d, e, f and g. Further, the subtypes a and g showed gradual decrease and increase, respectively, while subtype b showed abrupt initial increase and then gradual decrease. Transition from b to g could be direct or via one or more than one subtypes. Ultrastructure based analysis indicated that HOS response subtypes are the apparent reflection of the differences in the cytoskeletal assembly of the sperm tail and thus may be identifying different physiological variants in the sperm population. These results indicate that shorter incubation is essential to document the kinetics of various HOS responses but the conventional HOS test misses these important HOS features because of lengthy incubation. Since the time course of ordered transition of HOS responses will vary more than the total HOS response in semen of different aetiologies, the importance of HOS response subtypes and response evaluation time should be taken into consideration when applying HOS test.      

Evolution of neurotransmitter receptor systems

The presence of hormones, neurotransmitters, their receptors and biosynthetic and degradative enzymes is clearly not only associated with the present and the recent past but with the past several hundred million years. Evidence is mounting which indicates substantial conservation of protein structure and function of these receptors and enzymes over these tremendous periods of time. These findings indicate that the evolution and development of the nervous system was not dependent upon the formation of new or better transmitter substances, receptor proteins, transducers and effector proteins but involved better utilization of these highly developed elements in creating advanced and refined circuitry. This is not a new concept; it is one that is now substantiated by increasingly sophisticated studies. In a 1953 article discussing chemical aspects of evolution (Danielli, 1953) Danielli quotes Medawar, "... endocrine evolution is not an evolution of hormones but an evolution of the uses to which they are put; an evolution not, to put it crudely, of chemical formulae but of reactivities, reaction patterns and tissue competences." To also quote Danielli, "In terms of comparative biochemistry, one must ask to what extent the evolution of these reactivities, reaction patterns and competences is conditional upon the evolution of methods of synthesis of new proteins, etc., and to what extent the proteins, etc., are always within the synthetic competence of an organism. In the latter case evolution is the history of changing uses of molecules, and not of changing synthetic abilities." (Danielli, 1953). Figure 4 outlines a phylogenetic tree together with an indication of where evidence exists for both the enzymes that determine the biosynthesis and metabolism of the cholinergic and adrenergic transmitters and their specific cholinergic and adrenergic receptors. This figure illustrates a number of important points. For example, the evidence appears to show that the transmitters and their associated enzymes existed for a substantial period before their respective receptor proteins. While the transmitters and enzymes appear to exist in single cellular organisms, there is no solid evidence for the presence of adrenergic or cholinergic receptors until multicellular organisms where the receptors appear to be clearly associated with specific cellular and neuronal communication (Fig. 4). One can only speculate as to the possible role for acetylcholine and the catecholamine in single cell organisms.(ABSTRACT TRUNCATED AT 400 WORDS)