The altered expression of MHC-class II determinants on monocytes of cancer patients

Summary The expression of MHC class II determinants Ia.7 (detected by cross reactive mouse anti-Ia^k antibody) and HLA-DR on monocytes (MO) of gastric and colorectal cancer patients was examined. An increased proportion of MO bearing the Ia.7 determinant was found, while the number of MO expressing DR was not elevated. In gastric cancer patients the increased expression of the Ia.7 determinant was most pronounced in advanced cancer (stage IVA and IVB). The increased expression of this determinant was related to the presence of the tumour as the number of MO expressing Ia.7 decreased 6 months following surgical resection of the tumour. Further, the increased expression of Ia.7 on MO correlated with the tumour infiltration of the serosa. The Ia.7 determinants were mainly expressed on MO which also expressed the receptor for the Fc part of immunoglobulin. Immunostaining in cellular infiltrates surrounding the tumour revealed that Ia.7⁺ macrophages (MØ) were more numerous than in normal gastric mucosa and severe chronic gastritis and were mostly present in close proximity to tumour cells, while DR⁺ MØ were mainly localized within the stromal tissue of the tumour and their number was not increased in cancer infiltrates. These observations indicate that the Ia.7⁺ subpopulation of MØ may be involved in the anti-tumour response of the host.     

Revision of the Brazilian species of the genus Halipegus Looss, 1899 (Trematoda: Derogenidae)

Halipegus dubius Klein, 1905 is redescribed and illustrated from a Brazilian frog Leptodactylus ocellatus. The type-material of Halipegus genarchella (Travassos, Artigas & Pereira, 1928) and Halipegus parva (Travassos, Artigas & Pereira, 1928) are redescribed with original figures. New synonyms are proposed: Halipegus salmini Yamaguti, 1958 is considered a synonym of H. genarchella, H. tropicus (Manter, 1936) sensu Kloss (1966) of H. parva and Genarchella lenti Fábio, 1984 of H. overstreeti (Brooks, Mayes & Thorson, 1979) n. comb.     

Dissociation of fibrinogen and fibronectin binding from transglutaminase-mediated cross-linking at the hepatocyte surface

The interaction of fibrinogen and fibronectin with hepatocytes has been dissociated into distinct binding and cross-linking steps. Binding and cross-linking of 125I-labeled ligands were both decreased by transglutaminase inhibitors, but not by heparin or hirudin. Transglutaminase activity was manifest by Ca2+-dependent incorporation of [14C]putrescine into cells. Preferential cross-linking of fibrinogen A alpha over gamma chains, and lack of inhibition by heparin or hirudin indicates the involvement of tissue transglutaminase, and not Factor XIIIa. Hepatic transglutaminase activity, as well as binding and cross-linking of fibrinogen and fibronectin, were maximally supported by Ca2+, partially supported by Mn2+ and Sr2+, and markedly decreased by Mg2+ and Ba2+. In contrast, Co2+ supported binding but not cross-linking or transglutaminase activity, indicating that binding and cross-linking are dissociable events. This conclusion was corroborated by the finding that fibrinogen fragments D95 and D78 both inhibited Ca2+-dependent fibrinogen binding without being cross-linked themselves. Ligand binding in the presence of either cation was localized to the cell surface as evidenced by its trypsin sensitivity. Thus, fibrinogen and fibronectin binding to hepatocytes is independent of transglutaminase activity, whereas cross-linking of these adhesive macromolecules requires an enzymatically active cellular transglutaminase. In addition, fibrinogen binding appears to be mediated by molecular determinants present in fragment D78.     

Differential effects on active avoidance performance and locomotor activity of two major enkephalin metabolites, tyr-gly-gly and des-tyr-[leu]enkephalin

We examined the effects of two enkephalin metabolites, des-tyr-[leu]enkephalin and tyr-gly-gly, on one-way active avoidance conditioning in mice. These metabolites are products of the two major enkephalin hydrolyzing enzymes in plasma, aminopeptidase and angiotensin converting enzyme. Like [leu]enkephalin from which it may be formed, tyr-gly-gly impaired avoidance acquisition, and its dose-response function for this effect was U-shaped. Also like [leu]enkephalin, tyr-gly-gly did not alter locomotor activity. On the other hand, des-tyr-[leu]enkephalin, at the doses tested, was without effect on avoidance conditioning but produced decreased locomotion. These data suggest that the tyrosine end of the enkephalin molecule may be important for its effects on conditioning. Because of their low opioid potencies, it is unlikely that the behavioral actions of tyr-gly-gly and des-tyr-[leu]enkephalin are mediated through opioid receptors.     

Single breath of CO2 as a clinical test of the peripheral chemoreflex

Peripheral chemoreceptor responsiveness is usually examined clinically by hypoxic testing, but the usefulness of this approach is limited by safety considerations, and the interpretation of results may be confounded by the direct central nervous system effects of hypoxia. Therefore we examined the single-breath (SB) CO2 test to determine its reproducibility and applicability as a clinical test of peripheral chemoreceptor function. The technique involved the inhalation of a SB of 13% CO2 in air. The ventilatory response was determined from the increase in ventilation (VE) during the first 20 s after the test breath and from the difference in end-tidal PCO2 between the test breath and preceding control breaths. The peak increase in VE occurred during the second or third breath after the test breath, corresponding to a delay of approximately 10 s. The mean of 10 SB tests administered at 2- to 3-min intervals was taken as the subject's response. Five healthy subjects were tested in this manner on each of 6 consecutive days with the response having an interday coefficient of variation of 25 +/- 6% (SD). The response in 26 healthy females (aged 22-61 yr) was 0.32 +/- 0.11 l.min-1.Torr-1, and in 26 healthy males (aged 24-69 yr) the response was 0.38 +/- 0.14 (P NS). No significant correlation was found between the age of the subjects and their ventilatory response. Thirty-six of the subjects also underwent hyperoxic CO2 rebreathing tests, the response to which is dependent on central chemoreceptor function. No correlation was found between rebreathing and SB tests.(ABSTRACT TRUNCATED AT 250 WORDS)     

Nyctohemeral Rhythms of Gonadal, Thyroid and Pineal Function in the Hyperprolactinemic Male Rat

In young adult male rats bearing a donor anterior pituitary gland grafted for 3 weeks under a kidney capsule, serum prolactin (PRL) concentrations were elevated and exhibited a rhythm with the highest values in the light phase. Serum PRL in control animals did not exhibit a significant rhythm. Eutopic pituitary PRL content, manifesting a biphasic (12-hr) rhythm with crests during the day and night in controls, exhibited a similar pattern in grafted rats though an overall reduction in pituitary PRL content was seen in the grafted animals. Neither the normal biphasic serum testosterone rhythm nor the normal 24-hr rhythm (nocturnal surge) of pineal N-acetyltransferase activity and melatonin content were altered in the hyperprolactinemic rats. Serum thyroxine (T₄) and triiodothyronine (T₃) and their free indices (FT₄ I, FT₃ I) and serum thyrotropin (TSH) were highest during the day in controls and grafted rats and a 12-hr rhythmic component was detected in data for these variables. In the grafted animals, the 12-hr component was reflected in an additional peak at night detectable by testing of means. The overall serum T₄ FT₄ I, and TSH levels were lower in grafted rats though overall T₃ and FT₃I levels did not differ between grafted and controls. T₃ uptake (T₃ U) values were similar between controls and grafted rats, in both cases exhibiting a fall during the night. Changes in serum thyronines could not be explained by changes in serum binding as assessed by the T₃U₃ and thus may represent changes in thyroidal secretion of T₄. The rhythm in serum PRL of grafted rats suggests the presence of rhythmic circulating factor(s) capable of influencing ectopic lactotrophs. The reduced eutopic pituitary PRL content suggests a role for PRL in influencing eutopic lactotrophs in the pituitary-grafted hyperprolactinemic male rat model. Though circulating testosterone and pineal melatonin synthesis were not altered in this model, thyroid function appeared to be so.     

Tricyclic Imipramine Modification of the Circadian Rhythms of Hypothalamic Serotonin, its Precursors and Acid Catabolite in Individually Housed Rats

Circadian rhythms of serotonin (5HT), its precursors tryptophan (TP) and 5-hydroxy-tryptophan (5HTP) and its acid catabolite 5-hydroxy-indoleacetic acid (5HIAA), were determined in the hypothalamus of control rats and rats which had been treated continuously with subcutaneous imipramine (10 mg/kg/day) for 2 weeks.

Rats were individually housed and entrained to LD12:12. Controls showed the 5HT and TP peaks in the light and dark periods respectively, as reported in the literature, but no inverted correlation (antiphase) between SHT and 5HIAA rhythms.

Imipramine significantly modified circadian rhythm characteristics: the 5HT acrophase was advanced, that of TP and 5HIAA was delayed. Imipramine also significantly increased hypothalamic SHT and TP concentrations.     

Culture conditions for arresting and stimulating the proliferation of a rainbow trout fibroblast cell line,RTG-2

Summary Conditions for arresting and stimulating the proliferation of the rainbow trout fibroblast cell line RTG-2 have been examined and the time course of events after stimulation determined. Quiescent populations were achieved in two ways. Cultures grown to confluency without a medium change for at least 7 d had fewer than 5% of the cells in S phase and few mitotic figures. Cultures deprived of serum, which could be done for up to 3 d without a loss in cell number, also achieved quiescence. After 3 d without serum, less than 1% of cells were in S phase and mitotic figures were infrequent. Addition to these cultures of fresh serum-containing medium brought about the synchronous entry of cells into S phase and mitosis. For cultures in which either the medium had been changed after 7 d without a change or serum-containing medium had been added after 3 d of serum deprivation, DNA synthesis increased after a lag period of 20 to 24 h, was pronounced between 30 and 45 h, and then declined. This was followed by a peak in the mitotic index. These protocols for arresting and subsequently stimulating RTG-2 proliferation should allow the G₁-S transition to be studied in a representative of teleosts. This research was supported by Natural Sciences and Engineering Research Council of Canada grant to N. C. B.     

Selected chromosome counts of the Czechoslovak flora I

Chromosome numbers of the following nine taxa of the Czechoslovak flora are given:Atriplex rosea L.,Cardamine resedifolia L.,Groenlandia densa (L.)Fourr.,Isoëtes lacustris L.,Lysimachia nemorum L.,Parnassia palustris L.,Phelipanche caesia (Rchb.) Soják,Rumex patientia L. subsp.patientia andSymphytum officinale L. s. str. A new chromosome number of 2n=80 is reported forRumex patientia L. subsp.patientia. Chromosome numbers of another five taxa are first reported from Czechoslovakia. Each of the ascertained chromosome counts is discussed with respect to hitherto known reports.     

Biological effects of human gastrin I and II chemically modified at the C-terminal tetrapeptide amide.

Binding to gastrin receptors and gastric acid secretion experiments were performed with gastrin derivatives modified at the C-terminal tetrapeptide amide from HG-13 sequence. 1. When the ultimate phenylalanine amide was replaced by a phenethylester or a phenetylamide moiety, the resulting compound bound to gastrin receptors (Kd approximately 10 nM) and exhibited antagonist activity on gastrin-induced acid secretion in the anesthetized rat. 2. Changing the peptide bond between Trp and Leu residues to a -omega(CH2-NH)- bond resulted in a compound which also bound to gastrin receptors (Kd approximately 10 nM) but presented agonist activity on acid secretion in the rat. In contrast, when the peptide bond between Leu and Asp residues was replaced by a -omega(CH2-NH)- bond, the resulting compound was devoid of any affinity for gastrin receptor (Kd greater than 10(-6) M) and of any biological activity. 3. The HG-13 derivatives were synthesized in sulfated and unsulfated forms: O-sulfation of the HG-13 tyrosine residue did not change its intrinsic in vivo activity but enhanced its affinity for gastrin receptors (Kd approximately 0.3 nM). On the contrary, O-sulfation of the various chemically modified HG-13 had no significant effect in either in vitro or in vivo experiments. 4. Finally, no significant difference between binding on parietal (F3) and nonparietal (F1) cells was observed, in agreement with the presence of a gastrin-type receptor in these two cell populations.