Lysis of autologous human melanoma cells by in vitro allosensitized peripheral blood lymphocytes

Summary Peripheral blood lymphocytes (PBL) of melanoma patients were sensitized in vitro with lymphocytes of a single donor or with a pool of lymphocytes of 5–20 different donors. After 6–7 days, the cytotoxic activity of the sensitized PBL was tested against cultured autologous tumor cells and lymphocytes in a ⁵¹Cr-release assay. Tumor lysis was observed in 13 of 16 cases in which patients' PBL (Pt-PBL) were stimulated by a pool of allogeneic lymphocytes and in five out of seven cases when single sensitization was performed. In no case was lysis of autologous normal lymphocytes or blasts seen. Cultivation of Pt-PBL with irradiated autologous tumor cells never led to the induction of lymphocytes cytotoxic to melanoma cells. Lysability by pool-activated autologous Pt-PBL of fresh cryopreserved tumor cells was compared to that of short-term cultured tumor cells, and no significant differences were observed. Cold-target inhibition experiments indicated that the cytotoxicity of Pt-PBL was tumor-restricted since only autologous melanoma cells but not lymphocytes were able to inhibit the reaction. These results indicate that activation of Pt-PBL is necessary in order to elicit or amplify their antitumor activity.     

Proton-induced grana formation in chloroplasts. Distribution of chlorophyll-protein complexes and Photosystem II photochemistry

Lowering the pH of the incubation medium to pH 5.4 leads to grana formation morphologically similar to that induced by metal cations. The same phenomenon is observed in EDTA-washed chloroplasts, indicating that it is not due in part to electrostatic ‘masking’ by residual cations associated with the membranes. Digitonin fractionation studies have indicated that the distribution of the major chlorophyll-protein complexes between granal and stromal membrane regions is similar at pH 5.4 in the absence of Mg²⁺, and at pH 7.4 in the presence of Mg²⁺. Chlorophyll fluorescence induction studies have indicated that the primary photochemistry of Photosystem II (PS II) is stimulated by lowering the pH to 5.4, just as it is upon metal cation addition at higher pH values. The failure to observe such an increase at pH 5.4 by measuring electron transport to ferricyanide is attributed to a combination of an inhibition by this pH of electron transport at a site after Q reduction and an increase in the number of PS II centres detached from the plastoquinone pool. We conclude that the stacked configuration of chloroplast membranes leads to increased PS II primary photochemistry, which is most simply explained in terms of a redistribution of excitation energy towards PS II.     

Congenital coronary artery-left heart fistulas: Report of three cases

Of 59 patients who underwent operative correction of congenital coronary artery fistulas from May 1956 through May 1980 at our institution, three had fistulas that arose from the coronary artery and terminated in the left heart. The chief indication for surgical correction in such patients is the presence of symptoms or the development of complications, which include rupture, endocarditis, and congestive heart failure. The principal objective of repair is closure or obliteration of the fistulous communication and preservation of distal myocardial perfusion. Because symptoms and complications tend to occur with age, elective ligation is warranted during childhood, even in asymptomatic patients. The three cases described here, as well as the reviewed series of left heart fistulas, substantiate this fact. All three patients were symptomatic before operation and asymptomatic afterward.     

Na+-dependent,potential-sensitive l-ascorbate transport across brush border membrane vesicles from kidney cortex

l-Ascorbate is taken up into brush border vesicles from kidney cortex of rat, rabbit and guinea pig by an efficient, Na⁺-dependent and potential-sensitive transport process. This uptake shows saturation ($\text{K}{}_{\mathrm{<mtext>m</mtext><mtext>:0.1–0.3\; mM</mtext>}}$) and is strongly stimulated by low concentrations of N₃^?. Erythorbate (d-isoascorbate) seems to be another, but poorer, substrate of the same transporter.     

Interrelationship between oxygen consumption,superoxide anion and hydrogen peroxide formation in phagocytosing guinea pig polymorphonuclear leucocytes

The paper presents an experimental procedure for a simultaneous assay of oxygen consumption, O2- release and H2O2 accumulation at a very early stage of the respiratory burst that is induced by phagocytosis in guinea pig polymorphonuclear leucocytes. The main findings are as follows: (a) The oxygen consumption that is measurable does not correspond to all oxygen that is reduced. The relationship between the actual oxygen consumed and the amount that is reduced depends on the fate of the intermediate products O2- and H2O2. (b) O2- is measurable extracellularly by the reduction of cytochrome c. When cytochrome c oxidizes the extracellular O2-, molecular oxygen is formed. This fact is shown by a decrease of oxygen consumption. The molar ratio between the O2- detected and the oxygen given back is 1. (c) The amount of O2- released from the cells accounts for only a small part of oxygen actually reduced. (d) H2O2 is detectable only in the presence of NaN3. In this condition almost all oxygen consumed is recovered in the form of H2O2. The molar ratio O2/H2O2 is near unity. The amount of H2O2 derived from dismutation of O2- released is only an aliquot of the total H2O2 accumulated. Thus, most of H2O2 is derived from intracellular sources. (e) In the absence of inhibitors of H2O2 degrading reactions, no detectable accumulation of peroxide occurs. Under these conditions, the main part of H2O2 formed is degraded in almost equal amount by catalase and myeloperoxidase, while only a small aliquot is degraded by NaN3 insensitive reactions.     

Hypertrophic smooth muscle

The neurones from the wind-sensitive hairs on the locust head have been filled with cobalt chloride and intensified with silver. All the neurones project through the brain to the suboesophageal ganglion, some continue to the prothoracic ganglion and a few as far as the mesothoracic ganglion. Three different types of projection are described and a regrouping is proposed of Weis-Fogh's five hair fields into three areas. The distribution of the neurones from these areas is described in relation to other structures in the ganglion and is discussed in relation to the function of the hair fields in stability control and grooming.     

Experimental hybridization within the genus Triturus (Urodela: Salamandridae)

The spermatogenesis of 9 F₁ hybrids of Triturus cristatus carnifex × T. vulgaris meridionalis was studied in squash preparations of testicular fragments, treated by the C-staining method. The chromosome number of these hybrids was examined in spermatogonial metaphases and found to be diploid. The two parental sets were always recognized, which means that a regular, although heterospecific, amphimixis occurred (2n=n+n). Meiotic prophase I is greatly altered owing to a failure of typical chromosome pairing and chiasma formation. At metaphase I and/or meta-anaphase I, the effects of the hybrid combination of the 2 specific parental sets are clearly visible. Most primary spermatocytes contain only univalents. A few show chromosome associations (bivalents, trivalents and, more rarely, quadrivalent chains) besides univalents. Such associations are of 2 types: (a) intragenomal associations = associations of 2 chromosomes by a terminal (a¹) or subterminal chiasma (a²); (b) intergenomal associations = associations of 2 chromosomes by a terminal (b¹) or subterminal chiasma (b²). Univalents segregate at random while the associations often lag on the equatorial plane or migrate entire to a spindle pole. Primary spermatocytes with chromosome multivalents can encounter greater difficulties in accomplishing the first cytokinesis. Secondary spermatocytes are numerically and qualitatively unbalanced; however, some of them undergo spermiogenesis and can give rise to a small number of sperms, generally abnormal and never united in bundles. — Problems related to the occurrence of anomalous chiasmata and of intra- and inter-genomal homologies are discussed.     

On the identity of dnaP and dnaF genes of Bacillus subtilis

Summary The dnaP strains of Bacillus subtilis are altered in the initiation of DNA replication at high temperature (Riva et al., 1975). Fine mapping of the gene shows that it is located very close to the dnaF gene, described by Karamata and Gross (1970) and mapped by Love et al. (1976) in the polC region. The phenotype of both mutants is indistinguishable: the DNA synthesis stops at non permissive temperature after synthesizing an amount of DNA equivalent to the completion of the rounds of replication already initiated; at permissive temperature they are abnormally sensitive to MMS and are reduced in the ability to be transformed. Both mutants are to be considered as belonging to the dnaF locus.The dnaF gene is very close to the polC gene, which specifies the DNA polymerase III of B. subtilis. The DNA polymerase III of the dnaF mutants is not temperature sensitive in vitro, however, the level of this enzyme is lower by a factor of 4 or 5 in the dnaF mutants, at the permissive temperature. Following shift of dnaF cultures to the non permissive temperature, the level of DNA polymerase III activity specifically decreases further by a factor of at least 10 in the mutant, whereas the DNA polymerase I level is unaffected.The possible roles of the dnaF gene in the control of the cellular level of the DNA polymerase III, and the possibility of a regulatory role of DNA polymerase III in the initiation of DNA replication in bacteria are discussed.Abbreviations and symbols HPUra 6-(p-hydroxyphenylazo)-uracil; mic, minimum inhibitory concentration - MMS methyl-methanesufonate - Pol I Pol II and Pol III: DNA polymerase I, II and III respectively - PCMB parachloro-mercuri-benzoate     

Structural changes in smooth muscle cells during isotonic contraction

Summary Smooth muscle cells of the guinea-pig taenia coli were studied in light and electron microscopy, in condition of mild stretch or of isotonic contraction. During contraction the cells increase in transverse sectional area and their packing density passes from 94,000 · mm^-2 to 18,000 · mm^-2. The percentage increase in transverse sectional area of the taenia is approximately the same as the percentage decrease in length. Measurements of cell transverse sectional area suggest that the individual cells shorten and fatten more than the taenia as a whole. Whereas stretched muscle cells run parallel to each other and show a fairly smooth surface, isotonically contracted cells are twisted and entwine around each other. Their surfaces are covered with myriad processes and folds. Longitudinal, transverse or oblique stripes are seen in light microscopy in the contracted muscle cells and it is suggested that they are related to the characteristics of the cell surface. In electron microscopy a complex pattern of interdigitating finger-like and laminar processes is observed. Caveolae are mainly found on the evaginated parts of the cell surface, dense patches are mainly (but not always) found on the invaginated parts. Desmosome-like attachments between contracted cells are frequent. The collagen fibrils run approximately parallel to the stretched muscle cells; on the other hand, they run obliquely and transversely around the isotonically contracted cells.This work is supported by the Medical Research Council. I thank Miss E.M. Franke and Mr S.J. Sarsfield for excellent technical assistance