Biomedical subjects
Publications and source records attributed to R J Cross.
Virtually all aged, male, Fischer-344 rats have testicular tumors. The influence of this tumor on lymphocyte reactivity from aged Fischer-344 rats is unknown. In this report we demonstrate that neither the presence of this tumor nor the serum concentration of luteinizing hormone has an effect on the splenic mitogen reactivity of old animals.
Numerous reports indicate that both central nervous system (CNS) and immune system functions decline with age. We have previously shown that the CNS can modulate both mitogen-induced spleen cell proliferation and NK activity in young Fischer 344 rats. In the present study we have determined the effects of AHT lesions on the lymphocyte reactivity of aged Fischer 344 rats. These data show that lesions in the AHT of aged rats cannot modulate splenic mitogen responsiveness, however, NK activity is impaired. This differential effect may be due to multiple factors including enhanced splenic suppressor cell activity, the inability of the brain to send modulatory signals following lesioning, or the failure of the immune system to receive a neural signal and react to it.
Placement of bilateral electrolytic lesions in the preoptic-anterior hypothalamic area (AHT) of Fischer 344 rats results in decreased splenic NK activity as compared to control and normal animals. Animals with AHT lesions have a decrease in NK activity 4 and 7 days after lesion placement, with a return to normal activity by day 14. Fractionation of spleen cells on glass bead columns results in nonadherent and adherent cell fractions with NK activity. AHT lesions affect NK activity only in the adherent cell fraction. The removal of macrophages from this cell fraction did not restore NK activity. Moreover, this NK activity is not the result of cytotoxic macrophages. Hypophysectomy decreases NK activity in lesioned and non-lesioned animals, suggesting the influence of pituitary factors. These data indicate that the anterior hypothalamus is capable of modulating the cytotoxic activity of NK cells. Thus, neuroimmunomodulation may be a potential factor in susceptibility to some disease states such as viral infections and neoplasia.
Rats with bilateral electrolytic lesions of specific limbic nuclei show alterations in lymphoid cell number and in lymphocyte activation induced in vitro by concanavalin A (Con A). The number of splenocytes decreases after lesioning in the anterior hypothalamus (p less than 0.001), ventromedial hypothalamus (p less than .0.2), and mamillary bodies (p less than. 0.001). The number of thymocytes decreases after lesioning of the anterior hypothalamus (p less than 0.001) and increases after hippocampal lesioning (p less than 0.001). Spleen cell responsiveness to con A decreases subsequent to lesioning of the anterior hypothalamus, whereas reactivity was enhanced after lesion placement in the mamillary bodies (p less than 0.002), hippocampus (p less than 0.001), and amygdaloid complex (p less than 0.001). Thymocyte mitogen reactivity is increased by lesions of the hippocampus (p less than 0.001) and amygdaloid complex (p less than 0.001). These effects manifest themselves maximally 4 days after lesioning, with a return to normal by day 14. These preliminary data indicated that quantitative and qualitative lymphocyte functions are altered by ablation of selected brain nuclei, thereby suggesting the presence of neural modulation of immune function.
Electrolyte destruction of certain nuclei of the brain cause specific structural and functional changes in the immune system. Lesions in the preoptic-anterior hypothalamic area result in thymic involution and a decrease in the number and blastogenic reactivity of splenocytes. In contrast, lesions in the hippocampus increase thymic and splenic mitogenic responsiveness and cellularity. Hypophysectomy abrogates all changes in splenocyte number and function induced by hypothalamic and limbic lesions. The effects of ablating the hippocampus and amygdaloid complex on thymocyte number and function also are abolished. Hypothalamic lesions in hypophysectomized animals result in an increase in the number of thymocytes but suppressed mitogenic activity. These data indicated that neuroimmunomodulation is mediated predominantly but not exclusively by the pituitary gland.
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Animals with electrolytic pre-optic and anterior hypothalamic (AHT) lesions show impaired mitogen-induced lymphocyte blastogenesis which is restored by removal of a population of spleen cells with macrophage-like properties. Although suppressor macrophages are detectable in normal and control rats, substantially more activity is present following AHT destruction. Abrogation of lymphocyte activation does not result from increased numbers of splenic macrophages. These data indicate that one mechanism by which neuroimmunomodulation occurs is by induction of a qualitative alteration in the function of naturally occurring suppressor macrophages.
Rats with electrolytic anterior hypothalamic lesions show changes in lymphoid tissue cellularity and a decrease in the response to concanavalin A (Con A). This effect manifests itself maximally 4 days after lesioning, with a return to normal by day 14. The changes are not mediated through the release of corticosteroids. These data indicate the presence of a neuroendocrine pathway that is capable of modulating immune function.
The incidence of bacteriaemia and bacteriogenic shock was studied in 2 series of patients undergoing urological procedures. In the first series (A), 52 of 4333 urological patients had symptoms of bacteriogenic shock. Twenty-five of these had a positive blood culture, giving an incidence of shock with proven bacteriaemia of 0.58%. In the second series (B) 628 patients had blood cultures taken after urological procedures with an incidence of bacteriaemia of 12.7%. Bacteriaemia is most common after prostatic surgery (transurethral prostatectomy 2.7%, retropubic, prostatectomy 37%, prostatic biopsy 20%), and is usually due to Esch. coli, Proteus species and Ps. aeruginosa. In hospital practice these organisms are unlikely to be sensitive to common antibiotics and initial therapy with an aminoglycoside is justified, while awaiting the results of blood culture.
The cytotoxic drug combination of adriamycin and 5-fluorouracil has resulted in a 35% objective response in 20 patients with advanced bladder cancer. This has been achieved with minimal toxicity and on an out-patient basis. If the survival rate of patients with invasive bladder cancer is to be improved it seems likely that some form of systemic treatment will need to be added to the local measures currently in use. Further studies of different chemotherapeutic agents should help to define an effective and safe form of adjunvant therapy.
The results of a survey of dermatophyte infection in New-foundland for the period 1962 to 1968 are presented. A steady annual rise in the number of specimen submissions is noted, with positive findings in an average of 21.7%. The contribution by source of specimens is recorded, and species distribution indicates that Microsporum canis has behaved in epidemic form whereas other species appear endemic. Trichophyton rubrum infection shows a steady annual increase. No cases of favus have been noted. The distribution of species by anatomical site is indicated.
A method for the systematic cryopreservation of potato apices was developed by the Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH (DSMZ) and the Institute for Crop and Grassland Science of the Federal Agricultural Research Centre (FAL, Braunschweig). Designed specifically for routine use in genebanks, this method uses a very simple ultra-rapid freezing approach and was applied to a wide range of varieties within the Federal Centre for Breeding Research on Cultivated Plants (BAZ, Quedlinburg) Potato Collection. After several years of storage in liquid nitrogen, shoot tips from a random sample of 51 varieties were thawed and the survival and shoot regeneration percentages compared to those measured immediately after freezing. There were no major changes in either survival or recovery of frozen apices. Data presented are not the outcome of a systematic experiment but from that accumulated during our work from 1992 to 1999.