One of two growth hormone genes in coho salmon is sex-linked.

Salmonid fishes have two growth hormone genesresulting from their polyploid ancestry. We used the polymerase chain reactionto examine genetic variation in the third intron (C) of both of these genes incoho salmon (Oncorhynchus kisutch). A polymorphism in the length of intron C inGH-1 is due to a variable number of copies of a 31-nt repeat that is absent fromGH-1 of the closely related chinook salmon (Oncorhynchus tshawytscha) andrainbow trout (Oncorhynchus mykiss). Thus, this tandem repeat sequence hasbecome established in the genome of coho salmon since the separation of thisspecies from its closest relatives. All male coho salmon examined have an alleleat the second growth hormone gene, GH-2, that is not found in females. GH-2 isthus on the sex chromosome and there is no recombination between GH-2 and thesex-determining locus (SEX). Sequences of intron C indicate much greaterdivergence between the X chromosome-specific allele and the Ychromosome-specific allele within coho salmon than between the Xchromosome-specific alleles of coho and the closely related chinook salmon.Thus, absence of recombination between GH-2 and SEX apparently predatesseparation of these two species.     

Identification of normal B-cell counterparts of neoplastic cells which secrete cold agglutinins of anti-I and anti-i specificity

A monoclonal antibody, which recognizes a cross-reacting idiotypic determinant present on human cold-reactive autoantibodies with anti-I or anti-i binding activity, has been found to specifically inhibit the cold agglutination of red cells. This suggests that an epitope close to the binding site of such autoantibodies is being recognized. The antibody has been used to identify tumour cells in the blood of three patients with cold haemagglutinin disease, and to analyse the heterogeneous nature of the neoplastic B-cell clone present in the bone marrow of one of the patients. Using S-phase analysis, it was found that cell proliferation was occurring in the bone marrow but not in the blood, and that the major proliferating population was that of lymphoplasmacytoid cells containing large vesicular inclusions of idiotypic IgM. It has also been possible to locate normal B-cells which are recognized by the anti-idiotypic antibody. Such cells have been found throughout the normal adult lymphoid tissue where they account for 2.9-10.8% of the B lymphocyte population. They are also present in fetal spleen at 15 weeks gestation, indicating that immunoglobulins bearing this sequence form part of the immature B-cell repertoire.     

The human locus coeruleus: computer reconstruction of cellular distribution

Quantitative neuroanatomical techniques were developed to map the distribution of norepinephrine-containing locus coeruleus (LC) neurons in the adult human brain. These neurons reside in the dorsolateral pontine tegmentum and are identifiable by their neuromelanin pigment content. Five brains, ranging in age from 60 to 104 years, were examined. Outlines of coronal or sagittal sections containing the LC were entered into a computer along with the location of each cell, certain neuroanatomical landmarks, and cell size. Sections were aligned with specific neuroanatomical landmarks so that the computer-generated distribution of cells was representative of the in situ distribution of cells. Analysis of (1) the number of cells in sections throughout the rostrocaudal extent of the nucleus, (2) cell size, (3) 3-dimensional reconstructions of the distribution of cells within the brain stem, and (4) 2-dimensional cell-frequency maps, make it possible to quantitatively characterize the distribution of cells within this large nucleus. The total estimated number of LC cells on both sides of the brain ranged from 45,562 to 18,940 (youngest to oldest), and mean soma area ranged from 835 to 718 micron 2 (youngest to oldest). The nucleus is "tube-like" in shape, has a rostrocaudal extent of approximately 16 mm, and is bilaterally symmetrical. Two-dimensional cell-frequency maps were developed to illustrate the regional distribution of cell frequencies at any rostrocaudal/mediolateral point on the horizontal plane; the total unilateral area of the LC ranged from 32.8 to 17.2 mm2 (youngest to oldest). The techniques developed to characterize the 2- and 3-dimensional distributions of LC neurons can be used in future studies to quantitatively examine the effects of aging and disease on this and other brain nuclei.     

Effects of mast cell-macrophage interactions on the production of collagenolytic enzymes by metastatic tumor cells and tumor-derived and stromal fibroblasts

Histological examination of the metastatic rat mammary adenocarcinoma line MTLn3 showed that macrophages and mast cells were frequently localized at the tumor periphery in the stromal tissues adjacent to the zones of tumor invasion. The interactions of these host cells with tumor cells and tumor-associated fibroblasts could be important in stimulating the production of extracellular matrix-degrading enzymes that facilitate tumor invasion and metastatic spread. Therefore, we examined the effects of isolated, activated macrophages and mast cells on the secretion of collagenolytic activities by normal fibroblasts, metastatic mammary adenocarcinoma cells and tumor-associated fibroblasts. Medium from activated macrophages or degranulated mast cells stimulated significant increases in production of collagenolytic activities by normal and tumor-associated fibroblasts and MTLn3 tumor cells. Medium from activated macrophages that had been pretreated with medium from degranulated mast cells, however, were less stimulatory to fibroblasts and tumor cell production of collagenolytic activities than medium from degranulated mast cells alone. We also examined the effects of two cytokines, interleukin-1 and tumor necrosis factor-a on activated macrophage- and degranulated mast cell-stimulation of fibroblast and tumor cell collagenolytic activities. The two cytokines alone or in combination stimulated increased production of collagenolytic activities by fibroblasts and tumor cells. Addition of the cytokines to degranulated mast cell products resulted in secretion of higher collagenolytic enzyme activities by normal fibroblasts (but not by tumor-derived fibroblasts or tumor cells) than with degranulated mast cell product-treatment of either target cell alone. Cytokines used in combination with macrophage-conditioned medium were less effective in stimulating fibroblast and tumor cell collagenase activities than cytokines alone. Thus normal infiltrating host cells such as macrophages and mast cells can have profound effects on the production of degradative enzymes by tumor cells and tumor-associated stromal fibroblasts.     

A comparative study of the proteolytic enzymes of Trypanosoma brucei, T. equiperdum, T. evansi, T. vivax, Leishmania tarentolae and Crithidia fasciculata

Four types of proteolytic activity were detected in the bloodstream form of each of the four Trypanosoma species: (i) HPAase, active on hide powder azure and detected on polyacrylamide gels containing denatured haemoglobin; (ii) AZCase, active on azocasein; (iii) type 1, active on the chromogenic peptide N-benzoyl-L-prolyl-L-phenylalanyl-L-arginine p-nitroanilide in the presence of dithiothreitol, and (iv) type 2, active against several nitroanilide derivatives in the absence of dithiothreitol. Studies of the pH optimum, dithiothreitol requirement and inhibitor sensitivities of the proteolytic activities suggested that: (a) HPAase and type 1 activities could be due to the same enzymes, probably a family of cysteine proteinases; (b) AZCase had some characteristics of a cysteine proteinase, but was not identical to HPAase, and (c) type 2 activity could be due to a serine proteinase. Procyclic T. brucei contained relatively low cysteine proteinase activities (HPAase, AZCase and type 1) but high type 2 activity. Their proteolytic enzymes thus were apparently more similar to those in Crithidia fasciculata and Leishmania tarentolae promastigotes than those in T. brucei bloodstream forms.     

Neurotensin excitation of rat ventral tegmental neurones.

1. Whole-cell patch-clamp recordings were made from ventral tegmental area neurones in rat midbrain slices in vitro. In principal cells, which are presumed to contain dopamine, neurotensin (< or = 1 microM) caused an inward current at -60 mV in thirty of forty-seven neurones and had no effect on the remainder. In secondary neurones, neurotensin caused an inward current in twelve of thirty-three cells. 2. The inward current evoked by neurotensin reached a maximum amplitude of about 80 pA, and declined over several minutes when the application was discontinued. The current was most commonly accompanied by a decrease in membrane conductance and reversed polarity at a strongly hyperpolarized potential; this reversal potential was less negative in a higher extracellular potassium concentration. Neurotensin also caused an inward current even in potassium-free internal and external solutions; this current was accompanied by a conductance increase, reversed close to 0 mV and was inhibited by reduction of the extracellular sodium concentration (from 150 to 20 mM). 3. The inward current was associated with a large increase in noise; this persisted in calcium-free solutions but was inhibited by low sodium concentration. The increase in noise was more prominent at hyperpolarized potentials. The amplitude of the unitary current underlying the increase in noise was estimated from the ratio of the variance to the mean as about 1.5 pA at -100 mV. 4. When the recording was made with an electrode containing guanosine 5'-thio-triphosphate, the steady inward current evoked by neurotensin did not reverse when the application was discontinued. When the recording electrode contained pertussis toxin, the action of neurotensin was not different although outward currents evoked by dopamine and baclofen declined with time. 5. It is concluded that neurotensin excites ventral tegmental area neurones by activating a pertussis toxin-insensitive guanosine nucleotide-binding protein. This leads to a reduction in membrane potassium conductance and an increase in membrane sodium conductance, the relative contribution of which varies from cell to cell.     

LFA-1-dependent OKT3-driven T cell clusters in common variable immunodeficiency.

The triggering of the TCR/CD3 complex by anti-CD3 (OKT3) antibody leads to the formation of T cell clusters. In cultures of T lymphocytes from most normal individuals, the peak of cluster formation occurs at 24 h, but with cells from patients with common variable immunodeficiency (CVI) it was seen earlier at 4-9 h; in addition, the clusters were larger than normal, particularly at 9 h. Cluster formation by CVI and normal cells was dependent on temperature and divalent cations, but did not require Fc receptors. Since OKT3 clustering is known to be dependent on the LFA-1/ICAM-1 adhesion system, the effect of monoclonal antibodies directed against these molecules was tested. A potent inhibitor was the antibody against the common beta chain of the integrin family (CD18), but of four MoAbs against the alpha chains (CD11), three inhibited and one stimulated T cell aggregate formation. Increased expression of LFA-1 or ICAM-1 on CVI patients' T cells could not be demonstrated. The accelerated clustering was therefore probably due to an increase in the proportion of cells carrying the activated form of LFA-1. The formation of large numbers of homotypic lymphocyte clusters might reduce the effective interaction between B and T cells, thus contributing to the depression of immunoglobulin synthesis observed in this disease.