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Biomedical subjects

R Ananthakrishnan

Publications and source records attributed to R Ananthakrishnan.

At least 55 records · Page 3Linked to original sources
PubMed1976

Studies on the altered electrophoretic type of the factor VIII related antigen.

A distinct sub-group of von Willebrand's disease is characterized by an electrophoretically faster mobility of the factor VIII related antigen. Some of the physico-chemical properties of this variant antigen were investigated in this communication. The effect of temperature was tested by heating aliquots (0.5 ml) for 20 minutes at 45 degrees C, 56 degrees C and 65 degrees C. The variant was found to be denatured at 56 degrees C while the control was denatured at 65 degrees C. The effect of pH was tested by assessing the quantity (Laurell technique) and electrophoretic mobility (two dimensional immunoelectrophoresis) of the antigen in a variety of buffers ranging in pH from 7.0 to 9.5. The quantity of antigen was variable both among variants and controls and the electrophoretic mobility of the variant antigen was faster at all pH's. Molecular weight differences between the variant and controls were not detected since the chromatographic profile of the variant was similar to that of the controls in Sepharose 6 B using a 0.02 M Tris-NaCL buffer at pH 7.0. The affinity of the antigen for human antibody was heterogeneous although the variant exhibited less affinity for one of the human antibodies but not the other. The inhibitory effect was more pronounced in serum than in plasma. Purified IGG, however, did not show any inhibition, as the residual antigen assayed by the Laurell technique, was similar to the expected values. This would imply that non-IgG plasmatic factors could also play a part in the observed inhibition.

Antigen-Antibody Reactions↗
PubMed1976

Family studies of patients with reduced ristocetin aggregation and abnormalities of factor VIII and/or platelet function.

Factor VIII procoagulant activity (VIIIc), antigen (vWa), mobility of the antigen on two dimensional immunoelectrophoresis and platelet function were studied in 9 families with reduced ristocetin induced platelet aggregation rate (RIPA) and/or deficiency of plasma factor(s) required for ristocetin aggregation of washed normal platelets (vWf). the families could be subdivided into 4 groups. Group I showed dominant inheritance and reduced levels of VIIIc and vWa characteristic of typical von Willebrand's disease. All patients had reduced vWf and in 7 of 10 RIPA was reduced. Group II showed normal levels of VIIIc but reduced vWa. All showed reduced vWf but RIPA was reduced in one patient only. There was a good correlation between vWf and vWa and VIIIc in both groups. The bleeding time correlated with vWf in group I but not group II. Group III showed normal or nearly normal VIIIc and vWa but there was an increased mobility of vWa compared to normals and to groups I and II. RIPA was markedly reduced as was the vWf in one patient. Group IV is represented by one child with a strong family history of bleeding, who had reduced RIPA and defective platelet release reaction. The vWf in this child was normal and the ratio between VIIIc and vWa was similar to that seen in carriers of haemophilia. This spectrum of abnormalities of ristocetin aggregation justifies the use of the term 'von Willebrand's syndrome'.

Animals↗
PubMed1976

Polymorphism of phosphoglucomutase in a German breed cattle.

Haemolysates from cattle belonging to the Hochfleckvieh breed (N = 42), were studied for electrophoretic variation of phosphoglucomutase. Three phenotypes were observed which could be explained on the basis of two alleles PGM1A and PGM1B. The PGM1B frequency of 0.7325 is comparatively lower than in other breeds.

Alleles↗
PubMed1976

Assessment of the value of factor VIII procoagulant and antigen ratio in the diagnosis of carriers of haemophilia.

The detection rate of carriers of haemophilia was evaluated using the ratio of factor VIII procoagulant activity (VIIIc) to factor VIII antigen (VIIIag). In normals the corelation coefficient of VIIIc to VIIIag was 0.82. In 15 obligatory carriers of haemophilia whose VIIIc and VIIIag levels were studied in the authors' labotatory there was no correlation between VIIIc and VIIIag and the ratio of VIIIc to VIIIag was below the lowest normal value in 12 (80%). In all five obligatory carriers whose VIIIc levels were estimated in the referring institution and VIIIag levels in the authors' laborary the ratio was below the lowest normal value. In 17 sisters of haemophiliacs studied here or referred for estimation of VIIIag only, an abnormal ratio was found in seven. Of 25 mothers of haemophilic children without a family history of haemophilia carriers is close to that expected on theoretical grounds but the interpretation of the results is complicated by the small numbers of patients all of whose studies were performed entirely in the authors' laboratory. In two normal individuals, one of who was on a contraceptive pill, there were no fluctuations of the ratio of VIIIc to VIIIag during the menstrual cycle. In one obligatory carrier with a normal ratio there was also no fluctuation. It is concluded here that a measurement of the ratio of VIIIc to VIIIag is a valuable adjuvant in genetic counselling in haemophilia.

Adult↗
PubMed1975

[The geographic distribution of psoriasis].

On the basis of data published in the literature the geographical distribution of psoriasis vulgaris is described. One of the most interesting results is the increase of the psoriasis frequency in countries such as Japan, Korea, Kazachstan and East Africa. This could be due to the fact, that altered life conditions in connection with an increasing industrialization favour the manifestation of psoriasis genes. How far population differences of the psoriasis frequencies are to be seen exclusively as genetical ones, is hitherto unclear, but rather unlikely. No relations between psoriasis and climatec factors could be seen. Associations between psoriasis and several antigens (HL-A 13 and W 17) of the HL-A-systems seem to be present. These associations could be of considerable importance for the interpretation of the geographical distribution pattern of psoriasis. Further studies in psoriatic families are required, which describe the distribution of the HL-A specifities in the possibly potential psoriatic members of the families, who carry the respective genes.

Africa↗