Metabolic differences between primary cultures of astrocytes and neurons from cerebellum and cerebral cortex. Effects of fluorocitrate

Astrocytes and neurons cultured from mouse cerebellum and cerebral cortex were analyzed with respect to content and synthesis of amino acids as well as export of metabolites to the culture medium and the response to fluorocitrate, an, inhibitor of aconitase. The intracellular levels of amino acids were similar in the two astrocytic populations. The release of citrate, lactate and glutamine, however, was markedly higher from cerebellar than from cortical astrocytes. Neurons contained higher levels of glutamate, aspartate and GABA than astrocytic cultures. Cortical neurons were especially high in GABA and aspartate, and the level of aspartate increased specifically when the extracellular level of glutamine was elevated. Fluorocitrate inhibited the TCA cycle in the astrocytes, but was less effective in cerebellar neurons. Whereas neurons responded to fluorocitrate with an increase in the formation of lactate, reflecting, glycolysis, astrocytes decreased the formation of lactate in the presence of fluorocitrate, indicating that astrocytes to a high degree synthesize pyruvate and hence lactate from TCA cycle intermediates.     

Tumour-infiltrating lymphocytes mediate lysis of autologous squamous cell carcinomas of the head and neck

Tumour-infiltrating lymphocytes (TIL) and tumours from six patients with squamous cell carcinomas of the head and neck (SCCHN) were investigated. The six tumours all expressed major histocompatibility complex (MHC) class I antigens both in vivo and as tumor cell lines grown in vitro. In addition, the cancer cells either overexpressed the tumour-suppressor gene product p53 or harboured human papilloma virus 16/18 (HPV). The TIL were expanded in vitro in the presence of interleukin-2, immobilised anti-CD3 mAb and soluble anti-CD28 mAb. Expanded TIL cultures contained both CD4+and CD8+T cells, but generally contained few CD56+CD3-cells of the natural killer (NK) phenotype. CD8+T cells dominated the individual TIL cultures from five of the six patients and showed significant autologous tumour cell lysis. In TIL cultures derived from four of these tumour-reactive TIL cultures, killing could be partially blocked by an anti-MHC class I mAb. TIL cultures reacting with autologous tumour cells also showed strong TCR/CD3-redirected cytotoxicity when assayed against hybridoma cells expressing anti-TCR/CD3 mAb as well as natural-killer(NK)-like activity. A number of TIL cultures devoid of autologous tumour cell lysis were capable of lysing the natural-killer(NK)-sensitive K562 cell line suggesting that the SCCHN cells themselves are resistant to NK-like lysis. In conclusion, TIL cultures from head and neck carcinomas contain T cells which, upon expansion in vitro, can lyse autologous tumour cells in a MHC-class-I-restricted fashion. Thus, the results of the present study document that carcinomas of the head and neck in some patients are infiltrated by cytotoxic T cell precursors potentially capable of rejecting the autologous tumour.     

Meiotic chromatin diminution in a vertebrate,the holocephalan fish Hydrolagus collie (Chondrichthyes,Holocephali)

A histochemical, microdensitometric, and electron microscopic study of testes of the ratfish Hydrolagus colliei shows that an instance of the rare phenomenon of germ line chromatin diminution occurs in this vertebrate species. In primary spermatocytes at metaphase I a spherical mass of heterochromatin accumulates at one side of the metaphase plate. At anaphase I the heterochromatic mass is left in the equatorial cytoplasm and is passed into one of the two secondary spermatocytes formed during cytokinesis. As nuclear membranes are being restored, a double membrane envelope is also formed around the heterochromatic mass, which is then termed the ‘chromatin diminution body’ (CDB). At second meiotic division the CDB is included in the cytoplasm of one of the four spermatids and retained there, apparently unchanged, until mid-spermiogenesis. At that time the CDB becomes adherent to the spermatid plasma membrane and is pinched off from the spermatid by a process of apocrine exocytosis, taking a layer of spermatid plasma membrane along with it. Simultaneously this tri-membrane CDB is taken into the adjacent Sertoli cell by endocytosis, thereby acquiring a fourth membrane layer, a part of the Sertoli cell plasma membrane. The CDBs are subsequently phagocytized, possibly first fusing with dense, multilaminate bodies in the Sertoli cell cytoplasm. The CDB chromatin mass is strongly positive with the Feulgen method for DNA and the alkaline fast green method for histones. Microdensitometric analysis shows that the discarded chromatin amounts to about 10% of the diploid nuclear content and that it appears to be part of the normal diploid complement rather than DNA amplified during meiosis.     

On the multiplicity of platelet prostaglandin receptors: II. The use of N-0164 for distinguishing the loct of action for PGI2, PGD2, PGE2 and hydantoin analogs

The ω-chain variant analogs of prostacyclin (PGI₂) and PGD₂ in which the n-amyl side-chain has been replaced by a cyclohexyl group have been prepared and their cardiovascular activities have been compared to those of BW-245C(Fig. 1)(1) a potent anti-aggregatory vasodilator bearing a cyclohexyl-terminated side-chain on a hydantoin skeleton. The cyclohexyl group has little effect on PGI₂, but converts PGD₂ to a long lasting hypotensive agent and increases the platelet anti-aggregatory potency of PGD₂ by a factor of 8. The prostaglandin antagonist N-0164 selectively blocks the anti-aggregatory actions of PGD₂, cyclohexyl-PGD₂, and BW-245C; with essentially no effect on PGI₂, cyclohexyl-PGI₂ and PGE₂ at comparably effective doses. The latter observation is contrary to an earlier report by MacIntyre (2,3), but supports the view that the anti-aggregatory effect of high doses of PGE₂ ($\text{EC}{}_{50}\text{=50μ}\text{M}$) is mediated by the PGI₂ receptor (4). The hydantoin acts at the platelet PGD₂ receptor.     

Schistosoma mansoni and Fasciola hepatica: Cross-resistance in mice with single-sex schistosome infections

Primary Schistosoma mansoni single-sex infections in mice, i.e., either male only or female only, did not stimulate any detectable level of heterologous resistance to challenge with Fasciola hepatica after 22 to 76 days, while statistically significant resistance to a challenge with F. hepatica was demonstrated in the presence of patent mixed-sex S. mansoni infections. Simultaneous infections with S. mansoni and F. hepatica induced a statistically significant reduction in the number of schisto-some worms established, i.e., the burden being reduced by 40.1 and 43.9%, respectively. There was no reduction of the F. hepatica worm burden. Similar features could be observed with a time interval of 48 hr between the S. mansoni infection and the F. hepatica challenge, i.e., the schistosome burden being reduced by 34.2 and 45.6%, respectively. Furthermore, simultaneous infections with S. mansoni and F. hepatica induced a statistically significant reduction of the egg production capacity per paired female schistosome worm as compared with that of the S. mansoni control group. Tissue egg counts of the various intestinal sections were reduced by 92.8–99.6%.     

X-Linked mental retardation with fragile X. a pedigree showing transmission by apparently unaffected males and partial expression in female carriers

Summary A large family is reported in which mental retardation associated with the fragile site at Xq28 was found. Three normal males seemed to have transmitted the trait through their daughters to affected grandchildren.A total of 19 family members were investigated cytogenetically. Mentally retarded males showed macroorchidism and the fragile X. Three mentally retarded females were found, with the fragile X in a high percentage of cells; in contrast, the obligate carriers showed no or only few cells with the fragile X.     

On a general stochastic epidemic model

A non-Markovian epidemic model is proposed for which a stochastic epidemic threshold theorem, like that by Whittle (1955) for a simpler model, is shown to hold. The threshold theorem can be a useful guide in determining public health measures aimed at preventing major outbreaks of a communicable disease. Bounds are obtained for the mean size of minor epidemics. A parameter of the model, whose value is crucial to applications of these results, is the product of the infection rate and the mean duration of the infectious period. Estimators are suggested for this parameter by identifying martingales associated with counting processes of the epidemic model and by constructing other martingales which can be written as stochastic integrals.     

Sesquiterpenes of thalloid liverworts of the genera Conocephalum,Lunularia, Metzgeria and Riccardia

Thalloid liverworts of orders Metzgeriales and Marchantiales elaborate essential oils distinguishable from those of the Jungermanniales by the absence of β-barbatene and anastreptene. Riccardia sinuata elaborates a novel tricyclic exomethylene sesquiterpene of as yet undetermined structure. Conocephalum conicum elaborates cadinene-type sesquiterpenes. β-Cadinene from the latter species is clearly enantiomeric to the same product from vascular plants.