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Biomedical subjects

E Jacob

Publications and source records attributed to E Jacob.

At least 109 records · Page 6Linked to original sources
PubMed1977

A radioisotope dilution assay for unlabelled vitamin B12-intrinsic factor complex employing the binding intrinsic factor antibody: probable evidence for two types of binding antibody.

A new radioisotope dilution assay for vitamin B12-intrinsic factor complex is described. The method is based on the use of the binding type intrinsic factor antibody (the binding reagent), which when combined with the intrinsic factor-vitamin B12 complex (labelled ligand), is quantitatively adsorbed onto zirconium phosphate gel at pH 6.25. The new assay has been shown to provide a measure of intrinsic factor comparable with other intrinsic factor assays, but it has the important advantage of being able to measure the unlabelled vitamin B12-intrinsic factor complex (unlabelled ligand), and will, therefore, be valuable in the study of physiological events in the gastrointestinal tract. During the study, it was found that there is some evidence for a least two types of binding intrinsic factor antibody: One which combines preferentially with the intrinsic factor-vitamin B12 complex and one which combines equally well with this complex or with free intrinsic factor.

Antibodies↗
PubMed1977

A simple method for the separate measurement of transcobalamins I, II, and III: normal ranges in serum and plasma in men and women.

A simple method for the separate measurement of the unsaturated binding capacity of the three main circulating vitamin B12 binders, transcobalamins (TCs) I, II, and III, is described. The method involves batch separation of TC I and III from TC II by means of Quso G32, followed by batch separation of TC I from TC II with the use of diethylaminoethyl. The present study provides the first complete comparison of unsaturated TC I, II, and III in serum versus fluoridinated plasma of a single group of normal men versus women. There are consistently higher values in serum, largely due to an in vitro increment of TC III, prevented by NaF. The results are compared with values for some of these parameters obtained by others with the use of different methods, providing a standard for evaluating significance of results by various methods.

Adult↗
PubMed1977

Calcium and phosphorus metabolism in nephrotic syndrome.

Calcium and phosphorus balance studies were performed on 13 nephrotic patients and eight patients during clinical remission of the nephrotic syndrome. Marked impairment of intestinal absorption of calcium was found among nephrotic patients, in eight of whom faecal calcium equalled or exceeded dietary calcium. The mean faecal:dietary calcium ratio of nephrotic patients, 1-06 +/- 0-23 (SD), was significantly higher (p less than 0-005) than that of patients in remission, 0-58 +/- 0-21 (SD). The mean 24-hour urinary excretion of calcium of nephrotic patients, 0-68 +/- 0-68 (SD) mmol, was significantly lower (p less than 0-005) than that of patients in remission, 3-02 +/- 1-91 (SD) mmol. Calciferol administered to three nephrotic patients in the dosage of 1.25 mg per day did not significantly influence intestinal absorption or renal excretion of calcium. There was no difference between the two groups of patients in intestinal absorption or renal excretion of phosphorus; there was net intestinal absorption in all subjects. Quantitative bone histology was studied in seven of the nephrotic patients. None had osteomalacia or osteitis fibrosa, while only one had evidence of mild osteoporosis.

Adolescent↗
PubMed1976

Reiteration frequency of the histone genes in the genome of the amphibian, Xenopus laevis.

Radioactive RNA was obtained from Xenopus laevis gastrula-stage embryos which had been labelled by microinjection of [3H]uridine. A 9-12-S RNA fraction was isolated by phenol extraction of whole embryos followed by sucrose gradient centrifugation of the RNA and polyacrylamide gel electrophoresis. This RNA was identified as histone mRNA on the basis of its chemical and physical properties. On polyacrylamide gels the labelled RNA could be subfractionated into different components with electrophoretic mobilities similar to those of histone mRNAs of the sea urchin. 9-12-S RNA lacked poly(A) sequences. In a protein synthesis system in vitro the RNA fraction directed the synthesis of the histones H4, H2A, H2B, H3 and, possibly, of H1 protein. The Xenopus gistone mRNA was challenged with Xenopus DNA under conditions of vast DNA excess. A cot1/2 of between 110 and 250 mol-s-1(-1) was obtained from the RNA trace curve, indicating that the histone genes were 20-50-fold reiterated in the haploid genome of the species. This value indicates that although amphibians have several embryological and morphological features in common with sea urchins, the reiteration frequency for Xenopus histone genes is closer to the value of 10-20 established for mammals than the value of 400-1000 determined for sea urchins.

Animals↗
PubMed1976

Histone-gene reiteration in the genome of mouse.

Histone messenger RNA labelled to high specific activity has been isolated and purified from the mouse tissue-culture cell line L929. It had an electrophoretic mobility equivalent to a mean molecular weight of 1.4 X 10(5). The synthesis of this RNA was suppressed, but apparently not completely so, by inhibition of cellular DNA synthesis to more than 95% by addition of cytosine arabinoside. The synthesis of other RNA species remained unaffected by this treatment. Poly(A)-containing mRNA, representing a 20% contaminant of the electrophoretically purified histone mRNA, was removed by poly(U)-Sepharose chromatography. Histone mRNA thus purified was hybridized to DNA fractions enriched for histone genes of the sea urchin Psammechinus miliaris by actinomycin/CsCl gradient centrifugation. The mRNA was eluted from the hybrids and challenged with mouse DNA in vast DNA excess conditions. A (cot1/2) of 360 mol s 1(-1) was obtained from the RNA trace curve, suggesting a 10-20-fold reiteration of the histone genes in the haploid genome. Thus histone genes in mouse are much less highly reiterated than in sea urchins, but nevertheless are present in considerable excess over the number theoretically necessary for histone synthesis during the S phase of the cell cycle.

Animals↗
PubMed1976

T3 toxicosis and its relation to the iodide status in Singapore.

Baseline thyroid function tests (including total serum thyroxine iodide-T4I, total serum tri-iodothyronine T3 as well as T3 Sephadex Uptake Studies (T3U)) were determined in 82 normal Asian subjects. In addition, another group of normal volunteers (39) were assessed as regard serum and 24-hour urinary iodide levels to gauge the iodide status of the community; the results were comparable to that of goitre-free regions of the world. Having established the range of values of normal thyroid function tests, 103 consecutive clinically thyrotoxic patients (both new and relapsed cases) were similarly studied in an attempt to elucidate the magnitude of the problem of T3 toxicosis, and its relation to the iodide status in Singapore. Only three clinically hyperthyroid patients were foudn to have normal PBI T3 levels. A detailed analysis and discussion of the data is presented. It is concluded that T3 toxicosis is a rarity in Singapore.

Adult↗
PubMed1976

Serum ionized calcium in nephrotic syndrome.

Serum ionized calcium was measured in 12 patients with nephrotic syndrome and 14 nephrotic patients during clinical remission. All subjects had normal creatinine clearance and were not receiving treatment at the time of study. The mean serum ionized calcium values of the two groups of patients, 1-08 +/- 0-10 (SD) mmol/l ultrafiltrate and 1-21 +/- 0-10 (SD) mmol/l ultrafiltrate respectively, are significantly lower than the normal mean (1-28 +/- 0-06 (SD) mmol/l ultrafiltrate). The mean values of the patients in remission is, however, significantly higher (P less than 0-005) than that of the patients with manifest nephrotic syndrome. Elevated serum complexed calcium, and high serum protein-bound calcium in relation to serum albumin, were encountered, being more apparent in patients with overt nephrotic syndrome.

Adolescent↗
PubMed1975

Vitamin B12 absorption--a study of intraluminal events in control subjects and patients with tropical sprue.

The intraluminal fate of orally administered radioactive vitamin B12 has been studied in control subjects with normal vitamin B12 absorption and those with vitamin B12 malabsorption due to tropical sprue. In control subjects 1 to 21% of the dose was bound to sedimentable material and 37 to 75% was bound to immunoreactive intrinsic factor. In subjects with vitamin B12 malabsorption due to tropical sprue, the results were identical with the control subjects. Bacteriological studies showed a statistically significant correlation between both the number of flora in the jejunum and the number of bacteroides in both the jejunum and ileum and vitamin B12 malabsorption. In patients with tropical sprue who have normal intrinsic factor secretion, the vitamin B12 absorptive defect is not due to binding of the vitamin to bacteria or to alteration to the intrinsic factor vitamin B12 complex in the intestinal lumen. The lesion appears to be one of the mucosal cell receptors or of the cells themselves, possibly caused by bacterial toxins.

Bacteroides↗