摘要:

SummaryExtracts of annual ryegrass. (Lolium rigidum) infected withAnguinasp., andCorynebacteriumsp. and associated with an outbreak of annual ryegrass toxicity in sheep, were administered to 2‐week‐old rats by a single intraperitoneal injection. Rats that received a lethal dose of toxin developed neurological signs including incoordination and convulsions from the second day and most died between 2 and 7 days after injection. Histologically, the brains showed widespread lesions of focal necrosis consistent with anoxia. Peripheral circulation rate was greatly reduced after 3 days and gangrene of the tail and hind legs developed in some rats, Evidence of restricted blond How was also seen in kidneys, lungs and bruin. It was concluded that the toxin contains a long‐acting vasoconstrictor.

ISSN:0004-945X    

DOI:10.1038/icb.1977.18

出版商:Nature Publishing Group    

年代:1977

数据来源: WILEY

摘要:

SummaryThe ranges of variability of eight lysosomal acid hydrolases were examined in 47 cultured human skin fibroblast lines through 5 successive subcultures. No overall trend in activity values was found for any of the enzymes tested between the first and final subcultures. Similarly, no significant differences could be found between the overall ranges of fibroblast enzyme activity between 20 clinically normal children and 27 individuals being investigated for non‐specific metabolic diseases. It is concluded that for diagnostic reference purposes, wide ranges of normal enzyme values must be established. Such ranges can be validly drawn from a continuation of both clinical groups irrespective of the passage number (up to 5) of the cells at the time of isolation. It is noted that in certain cell lines derived from Fabry and Gaucher patients the ‘residual’ activity of the expectedly deficient enzyme could not easily be distinguished from the lowest values observed in normals, whereas, as expected, the activity of cells derived from patients with GM1and GM2gangliosidoses was markedly reduced.

ISSN:0004-945X    

DOI:10.1038/icb.1977.19

出版商:Nature Publishing Group    

年代:1977

数据来源: WILEY

摘要:

SummarySome of the factors which are to be considered in the antenatal diagnostic evaluation of lysosomal enzyme levels in cultured amniotic fluid cells are discussed in the light of eight consecutive cases in which the foetuses had a 1 in 4 chance of being homozygous for a lysosomal storage disease. There were 2 possible cases of GM1gangliosidosis, 2 of neuropathic Gaucher's disease, 1 of Krabbe's disease and 2 of Pompe's disease. Each infant was predicted to be unaffected; the assessments were confirmed to be correct post‐natally–7 by enzyme studies. Using a micro technique, 5 of the assessments were available in 28 days or less following amniocentesis. It is concluded that in certain circumstances skin fibroblasts may be used as valid controls and that the variability of assay results strongly militates against the confident assignment of heterozygous status and may cause difficulties in the identification of the homozygote in cases where ‘residual’ enzyme activity is high; concomitant family studies assist in the resolution of such problems.

ISSN:0004-945X    

DOI:10.1038/icb.1977.20

出版商:Nature Publishing Group    

年代:1977

数据来源: WILEY

摘要:

SummaryThe origin of IgA‐containing cells in sheep intestinal lymph was determined by antigenically stimulating a mesenteric lymph node and by studying afferent intestinal lymph.Since antigenic stimulation of the node resulted almost exclusively in the appearance of IgG1antibody‐containing cells, it was proposed that IgA‐containing cells are normally produced either in the Peyer's patches or lamina propria of the intestine.These conclusions were supported by studying lymph obtained by cannulation of a lymphatic duct afferent to the mesenteric lymph node. Study of the cells in afferent lymph revealed the presence of a significant population of IgA‐containing blast cells. This was convincing evidence that the IgA‐containing cells normally found in intestinal lymph originate from sites in the intestine.

ISSN:0004-945X    

DOI:10.1038/icb.1977.21

出版商:Nature Publishing Group    

年代:1977

数据来源: WILEY

摘要:

SummaryThe results presented below show that the dividing and adult forms ofT. lewisishare common antigens and indicate that the persistence of adult forms in the circulation of rats immune to reinfection is not due to a change in surface antigens as has been postulated. Using a rabbit anti‐rat immunoglobulin serum, the presence of rat immunoglobulins on the surface of adult trypanosomes could be demonstrated. These immunoglobulins were not complement‐fixing or opsonic. It is suggested that these immunoglobulins are responsible for the persistence of the adult forms in the circulation of the rat.

ISSN:0004-945X    

DOI:10.1038/icb.1977.22

出版商:Nature Publishing Group    

年代:1977

数据来源: WILEY

摘要:

SummaryA stable preparation which retains enhancement activity for the growth of murine granulocyte‐macrophage colonies in agar culture has been extracted from human and rat erythrocytes by osmotic lysis and high speed centrifugation.Trypsin digestion followed by Sephadex G‐25 column chromatography has resulted in the removal of haemoglobin and the isolation of an active fraction with an apparent molecular weight of 900 to 1000 daltons. Enhancement activity was abolished by n‐ethylmaleimide (NEM) treatment, suggesting that the enhancement is dependent on the presence of free sulphydryl groups.

ISSN:0004-945X    

DOI:10.1038/icb.1977.23

出版商:Nature Publishing Group    

年代:1977

数据来源: WILEY

摘要:

SummarySyringe pumps are almost universally used for constant perfusion oesophageal manometry, despite important technical limitations. A pneumatically driven perfusion pump has been designed specifically for oesophageal manometry. This pump requires less than one third the flow setting of a syringe pump to achieve a given rate of pressure rise. It is simple to operate and needs infrequent refilling. Nearly two years' practical experience with this pump has confirmed its superiority over the syringe pump for constant perfusion manometry.

ISSN:0004-945X    

DOI:10.1038/icb.1977.24

出版商:Nature Publishing Group    

年代:1977

数据来源: WILEY

摘要:

SummaryIn twenty‐nine gentamicin‐resistant strains (mostlyKlebsiellaspecies) isolated from four Melbourne hospitals over a six month period, the genes for gentamicin resistance were carried on conjugative plasmids belonging to the rare incompatibility group L. These plasmids conferred resistance to gentamicin and sisomycin but not to amikacin or tobramycin, and were inferred to specify the enzyme aminoglycoside 3‐N‐acetyltransferase (AAC(3)I or GAT I). In addition, they specified resistance to a number of other antibiotics, including ampicillin and carbenicillin, chloramphenicol, kanamycin and neomycin, spectinomycin and streptomycin, sulphonamides and tetracyclines. Although they had a wide host range amongst theEnterobacteriaceae, none of these plasmids appeared able to transfer toPseudomonas.

ISSN:0004-945X    

DOI:10.1038/icb.1977.25

出版商:Nature Publishing Group    

年代:1977

数据来源: WILEY

摘要:

SummarySteady‐state rate equations are written on the basis of information obtained from the literature describing the kinetics of the four enzyme‐catalysed reactions comprising the urea cycle. These equations are formulated into a set which also accounts for fluxes of input and output compounds external to the cycle. Numerical integration of this set of equations is performed employing parameters selected to approximate those pertaining to the operation of the urea cycle in normal liver. The result is a pattern of intermediate metabolite concentrations, which forms a basis for the comparison of patterns reflecting the effects of inborn errors of metabolism. The latter are calculated by varying specified kinetic parameters in the numerical integration. Each of the observed clinical syndromes, Hyperarginemia Types I and II, Hyperarginemia, Citrullinemia and Argininosuccinicaciduria, is discussed.

ISSN:0004-945X    

DOI:10.1038/icb.1977.26

出版商:Nature Publishing Group    

年代:1977

数据来源: WILEY

摘要:

SummaryActivities of the brush border enzymes alkaline phosphatase, leucine aminopeptidase and lactase and the lysosomal enzymes α‐mannosidase and β‐N‐acetylglucosaminidase increased in the serum of newly‐bum lambs fed colostrum. Feeding lipid and protein components of colostrum and bovine serum resulted in enzyme responses simitar to those observed after feeding colostrum. Activities of each of the enzymes increased in mesenteric lymph collected from newly‐born lambs when immunoglobulins were being absorbed from the jejunum and ileum.

ISSN:0004-945X    

DOI:10.1038/icb.1977.27

出版商:Nature Publishing Group    

年代:1977

数据来源: WILEY