9 research outputs found
ΠΠ΅Π½Π΅ΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ Π°ΡΠΏΠ΅ΠΊΡΡ ΡΠ°Π·Π²ΠΈΡΠΈΡ ΠΈΠ΄ΠΈΠΎΠΏΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΠΈΠ±ΡΠΈΠ»Π»ΡΡΠΈΠΈ ΠΏΡΠ΅Π΄ΡΠ΅ΡΠ΄ΠΈΠΉ Ρ Π±ΠΎΠ»ΡΠ½ΡΡ Π±Π΅Π· ΡΡΡΡΠΊΡΡΡΠ½ΡΡ ΡΠ΅ΡΠ΄Π΅ΡΠ½ΡΡ Π°Π½ΠΎΠΌΠ°Π»ΠΈΠΉ
Background: Atrial fibrillation (AF) is the most common cardiac arrhythmia. Among patients with AF the subgroup posessing AF without traditional risk factors is differentiated. Such patients are commonly referred as having lone AF and comprise 1020% of all cases. A number of studies have demonstrated that the background of AF, and in particular lone AF, have a substantial genetic component.
Aims: To evaluate the influence of gene polymorphism to the development of atrial fibrillation in patients without concomitant valvular pathology and coronary artery disease.
Materials and methods: The study included 174 patients with atrial fibrillation and 124 controls without any cardiovascular pathology. All patients were divided into two subgroups: with lone AF (n=94) and with concomitant arterial hypertension (n=80). All patients underwent a complex of clinical, instrumental (ECG, echocardiography, computed tomography of the pulmonary veins) and laboratory tests (thyroid hormones, inflammatory markers, fibrosis), as well as genetic analysis (determination of single nucleotide polymorphisms described as AF risk factors in genes AGXT2, PDE4D, SLN, SCN5A, PITX2, PRRX1, ZFHX3, TBX5, CAV1 ΠΈ HCN4).
Results: For the rare polymorphisms rs12291814 (SLN) and rs137854601 (SCN5A) wasnt found anyone carrier of the minor allele (C and A, respectively). In the both patient subgroups the minor allele T of rs2200733 in PITX2 (OR=3.18, p0.0001), minor allele G of rs3903239 in PRRX1, and minor alleles A of 2 polymorphisms rs2106261 and rs7193343 in ZFHX3 gene were revealed as risk factor of AF (OR=2.96, p0.0001, OR=2.02, p=0.0045, OR=1.64, p=0.04, respectively). We also revealed significant difference between AF and control groups for rs3807989 in CAV1: homozygotic state of minor allele A has a protective effect on the development of arrhythmias (OR=0.39).
Conclusions: We revealed the association between the polymorphisms in genes regulating transcription and the development of atrial fibrillation. These polymorphisms have already described but their frequencies have never investigated in Russian population. But the polymorphisms influence to gene functions stays unclear, although attempts to investigate relationship between genotype and gene expression have been made. When the relationship will be discovered it can help us to modify our approach in treatment to patients with atrial fibrillation.ΠΠ±ΠΎΡΠ½ΠΎΠ²Π°Π½ΠΈΠ΅. Π€ΠΈΠ±ΡΠΈΠ»Π»ΡΡΠΈΡ ΠΏΡΠ΅Π΄ΡΠ΅ΡΠ΄ΠΈΠΉ Π½Π°ΠΈΠ±ΠΎΠ»Π΅Π΅ ΡΠ°ΡΡΠΎ Π²ΡΡΡΠ΅ΡΠ°ΡΡΠ°ΡΡΡ Π°ΡΠΈΡΠΌΠΈΡ. ΠΡΠΈΠΌΠ΅ΡΠ½ΠΎ Π² 1020% ΡΠ»ΡΡΠ°Π΅Π² Π΄Π°Π½Π½ΠΎΠ΅ Π½Π°ΡΡΡΠ΅Π½ΠΈΠ΅ ΡΠΈΡΠΌΠ° ΡΠ΅ΡΠ΄ΡΠ° Π²ΠΎΠ·Π½ΠΈΠΊΠ°Π΅Ρ Ρ Π±ΠΎΠ»ΡΠ½ΡΡ
Π±Π΅Π· ΡΠΎΠΏΡΡΡΡΠ²ΡΡΡΠ΅ΠΉ ΠΊΠ°ΡΠ΄ΠΈΠ°Π»ΡΠ½ΠΎΠΉ ΠΈ ΡΠΊΡΡΡΠ°ΠΊΠ°ΡΠ΄ΠΈΠ°Π»ΡΠ½ΠΎΠΉ ΠΏΠ°ΡΠΎΠ»ΠΎΠ³ΠΈΠΈ. Π ΡΡΠΈΡ
ΡΠ»ΡΡΠ°ΡΡ
ΠΏΡΠΈΠΌΠ΅Π½ΡΠ΅ΡΡΡ ΡΠ΅ΡΠΌΠΈΠ½ ΠΈΠ·ΠΎΠ»ΠΈΡΠΎΠ²Π°Π½Π½Π°Ρ ΠΈΠ»ΠΈ ΠΈΠ΄ΠΈΠΎΠΏΠ°ΡΠΈΡΠ΅ΡΠΊΠ°Ρ ΡΠΈΠ±ΡΠΈΠ»Π»ΡΡΠΈΡ ΠΏΡΠ΅Π΄ΡΠ΅ΡΠ΄ΠΈΠΉ. Π Π·Π½Π°ΡΠΈΡΠ΅Π»ΡΠ½ΠΎΠΉ ΡΠ°ΡΡΠΈ ΡΠ»ΡΡΠ°Π΅Π² ΡΠ°Π·Π²ΠΈΡΠΈΡ ΠΈΠ΄ΠΈΠΎΠΏΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΠΈΠ±ΡΠΈΠ»Π»ΡΡΠΈΠΈ ΠΏΡΠ΅Π΄ΡΠ΅ΡΠ΄ΠΈΠΉ ΠΏΡΠ΅Π΄ΠΏΠΎΠ»Π°Π³Π°Π΅ΡΡΡ ΡΠΎΠ»Ρ Π³Π΅Π½Π΅ΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΡΠ°ΠΊΡΠΎΡΠΎΠ². ΠΠ°ΠΈΠ±ΠΎΠ»ΡΡΠΈΠΉ ΠΈΠ½ΡΠ΅ΡΠ΅Ρ Π΄Π»Ρ ΠΈΠ·ΡΡΠ΅Π½ΠΈΡ ΠΏΡΠ΅Π΄ΡΡΠ°Π²Π»ΡΡΡ ΡΠ»ΡΡΠ°ΠΈ Π½Π΅ΡΠ΅ΠΌΠ΅ΠΉΠ½ΠΎΠΉ ΡΠΎΡΠΌΡ Π°ΡΠΈΡΠΌΠΈΠΈ, ΠΎΠ±ΡΡΠ»ΠΎΠ²Π»Π΅Π½Π½ΡΠ΅ ΠΏΠΎΠ»ΠΈΠΌΠΎΡΡΠΈΠ·ΠΌΠΎΠΌ Π³Π΅Π½ΠΎΠ², ΠΎΡΠ²Π΅ΡΡΡΠ²Π΅Π½Π½ΡΡ
Π·Π° ΠΊΠ°ΡΠ΄ΠΈΠΎΠ³Π΅Π½Π΅Π· ΠΈ ΡΠ΅Π³ΡΠ»ΠΈΡΡΡΡΠΈΡ
Π°ΠΊΡΠΈΠ²Π½ΠΎΡΡΡ Π΄ΡΡΠ³ΠΈΡ
Π³Π΅Π½ΠΎΠ².
Π¦Π΅Π»Ρ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΠ΅ ΡΠΎΠ»ΠΈ ΡΡΠ΄Π° ΠΎΠ΄Π½ΠΎΠ½ΡΠΊΠ»Π΅ΠΎΡΠΈΠ΄Π½ΡΡ
ΠΏΠΎΠ»ΠΈΠΌΠΎΡΡΠΈΠ·ΠΌΠΎΠ² Π² ΡΠ°Π·Π²ΠΈΡΠΈΠΈ ΠΈΠ΄ΠΈΠΎΠΏΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΠΈΠ±ΡΠΈΠ»Π»ΡΡΠΈΠΈ ΠΏΡΠ΅Π΄ΡΠ΅ΡΠ΄ΠΈΠΉ.
ΠΠ΅ΡΠΎΠ΄Ρ. ΠΠ±ΡΠ»Π΅Π΄ΠΎΠ²Π°Π½Ρ 174 ΠΏΠ°ΡΠΈΠ΅Π½ΡΠ° Ρ ΡΠΈΠ±ΡΠΈΠ»Π»ΡΡΠΈΠ΅ΠΉ ΠΏΡΠ΅Π΄ΡΠ΅ΡΠ΄ΠΈΠΉ ΠΈ Π³ΡΡΠΏΠΏΠ° ΠΊΠΎΠ½ΡΡΠΎΠ»Ρ Π² ΠΊΠΎΠ»ΠΈΡΠ΅ΡΡΠ²Π΅ 124 ΡΠ΅Π»ΠΎΠ²Π΅ΠΊ Π±Π΅Π· ΡΠ΅ΡΠ΄Π΅ΡΠ½ΠΎ-ΡΠΎΡΡΠ΄ΠΈΡΡΠΎΠΉ ΠΏΠ°ΡΠΎΠ»ΠΎΠ³ΠΈΠΈ. ΠΠ°ΡΠΈΠ΅Π½ΡΡ Π±ΡΠ»ΠΈ ΡΠ°Π·Π΄Π΅Π»Π΅Π½Ρ Π½Π° Π΄Π²Π΅ ΠΏΠΎΠ΄Π³ΡΡΠΏΠΏΡ Ρ ΠΈΠ·ΠΎΠ»ΠΈΡΠΎΠ²Π°Π½Π½ΠΎΠΉ ΡΠΎΡΠΌΠΎΠΉ ΡΠΈΠ±ΡΠΈΠ»Π»ΡΡΠΈΠΈ ΠΏΡΠ΅Π΄ΡΠ΅ΡΠ΄ΠΈΠΉ (n=94) ΠΈ Ρ ΡΠΎΠΏΡΡΡΡΠ²ΡΡΡΠ΅ΠΉ Π°ΡΡΠ΅ΡΠΈΠ°Π»ΡΠ½ΠΎΠΉ Π³ΠΈΠΏΠ΅ΡΡΠ΅Π½Π·ΠΈΠ΅ΠΉ (n=80). ΠΡΠ΅ΠΌ ΠΏΠ°ΡΠΈΠ΅Π½ΡΠ°ΠΌ ΠΏΡΠΎΠ²ΠΎΠ΄ΠΈΠ»ΡΡ ΠΊΠΎΠΌΠΏΠ»Π΅ΠΊΡ ΠΊΠ»ΠΈΠ½ΠΈΠΊΠΎ-ΠΈΠ½ΡΡΡΡΠΌΠ΅Π½ΡΠ°Π»ΡΠ½ΡΡ
(ΡΠ»Π΅ΠΊΡΡΠΎ-, ΡΡ
ΠΎΠΊΠ°ΡΠ΄ΠΈΠΎΠ³ΡΠ°ΡΠΈΡ; ΠΊΠΎΠΌΠΏΡΡΡΠ΅ΡΠ½Π°Ρ ΡΠΎΠΌΠΎΠ³ΡΠ°ΡΠΈΡ Π»Π΅Π³ΠΎΡΠ½ΡΡ
Π²Π΅Π½) ΠΈ Π»Π°Π±ΠΎΡΠ°ΡΠΎΡΠ½ΡΡ
(Π³ΠΎΡΠΌΠΎΠ½Ρ ΡΠΈΡΠΎΠ²ΠΈΠ΄Π½ΠΎΠΉ ΠΆΠ΅Π»Π΅Π·Ρ; ΠΌΠ°ΡΠΊΠ΅ΡΡ Π²ΠΎΡΠΏΠ°Π»Π΅Π½ΠΈΡ, ΡΠΈΠ±ΡΠΎΠ·Π°) ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΉ, Π° ΡΠ°ΠΊΠΆΠ΅ Π²ΡΠΏΠΎΠ»Π½Π΅Π½ΠΎ Π³Π΅Π½ΠΎΡΠΈΠΏΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ ΠΏΠΎ ΠΏΠΎΠ»ΠΈΠΌΠΎΡΡΠ½ΡΠΌ ΠΎΠ΄Π½ΠΎΠ½ΡΠΊΠ»Π΅ΠΎΡΠΈΠ΄Π½ΡΠΌ ΠΌΠ°ΡΠΊΠ΅ΡΠ°ΠΌ Π³Π΅Π½ΠΎΠ² SLN (Π³Π΅Π½ ΡΠ°ΡΠΊΠΎΠ»ΠΈΠΏΠΈΠ½Π°), SCN5A (Π³Π΅Π½ -ΡΡΠ±ΡΠ΅Π΄ΠΈΠ½ΠΈΡΡ ΠΏΠΎΡΠ΅Π½ΡΠΈΠ°Π»Π·Π°Π²ΠΈΡΠΈΠΌΠΎΠ³ΠΎ Π½Π°ΡΡΠΈΠ΅Π²ΠΎΠ³ΠΎ ΠΊΠ°Π½Π°Π»Π° ΡΠΈΠΏΠ° V), PITX2 (Π³Π΅Π½ ΠΏΠ°ΡΠ½ΠΎΠ³ΠΎ Π³ΠΎΠΌΠ΅ΠΎΠ΄ΠΎΠΌΠ΅Π½Π° 2), PRRX1 (Π³Π΅Π½ ΠΏΠ°ΡΠ½ΠΎΠ³ΠΎ Π³ΠΎΠΌΠ΅ΠΎΠ±ΠΎΠΊΡ-Π±Π΅Π»ΠΊΠ° 1), ZFHX3 (Π³Π΅Π½ ΡΠΈΠ½ΠΊΠΎΠ²ΠΎ-ΠΏΠ°Π»ΡΡΠ΅Π²ΠΎΠ³ΠΎ Π³ΠΎΠΌΠ΅ΠΎΠ±ΠΎΠΊΡ-Π±Π΅Π»ΠΊΠ°), CAV (Π³Π΅Π½ ΠΊΠ°Π²Π΅ΠΎΠ»ΠΈΠ½Π°).
Π Π΅Π·ΡΠ»ΡΡΠ°ΡΡ. ΠΠ»Ρ ΠΌΠ°ΡΠΊΠ΅ΡΠΎΠ² rs12291814 Π³Π΅Π½Π° SLN ΠΈ rs137854601 Π³Π΅Π½Π° SCN5A Π½Π΅ Π²ΡΡΠ²Π»Π΅Π½ΠΎ Π½ΠΈ ΠΎΠ΄Π½ΠΎΠ³ΠΎ Π½ΠΎΡΠΈΡΠ΅Π»Ρ ΠΌΠΈΠ½ΠΎΡΠ½ΠΎΠ³ΠΎ Π°Π»Π»Π΅Π»Ρ (ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²Π΅Π½Π½ΠΎ Π‘ ΠΈ Π), ΡΡΠΎ Π½Π΅ ΠΏΡΠΎΡΠΈΠ²ΠΎΡΠ΅ΡΠΈΡ Π»ΠΈΡΠ΅ΡΠ°ΡΡΡΠ½ΡΠΌ Π΄Π°Π½Π½ΡΠΌ. ΠΠ»Ρ ΠΏΠΎΠ»ΠΈΠΌΠΎΡΡΠ½ΡΡ
ΠΌΠ°ΡΠΊΠ΅ΡΠΎΠ² rs2200733 Π³Π΅Π½Π° PITX2, rs3903239 Π³Π΅Π½Π° PRRX1 ΠΈ Π΄Π²ΡΡ
ΠΏΠΎΠ»ΠΈΠΌΠΎΡΡΠ½ΡΡ
ΠΌΠ°ΡΠΊΠ΅ΡΠΎΠ² rs2106261 ΠΈ rs7193343 Π³Π΅Π½Π° ZFHX3 ΠΌΠΈΠ½ΠΎΡΠ½ΡΠΉ Π°Π»Π»Π΅Π»Ρ ΡΠ²Π»ΡΠ΅ΡΡΡ ΡΠ°ΠΊΡΠΎΡΠΎΠΌ ΡΠΈΡΠΊΠ° Π°ΡΠΈΡΠΌΠΈΠΈ Π΄Π»Ρ ΠΎΠ±Π΅ΠΈΡ
ΠΏΠΎΠ΄Π³ΡΡΠΏΠΏ ΠΏΠ°ΡΠΈΠ΅Π½ΡΠΎΠ². ΠΠ»Ρ ΠΏΠΎΠ»ΠΈΠΌΠΎΡΡΠ½ΠΎΠ³ΠΎ ΠΌΠ°ΡΠΊΠ΅ΡΠ° rs3807989 Π³Π΅Π½Π°, ΠΊΠΎΠ΄ΠΈΡΡΡΡΠ΅Π³ΠΎ ΠΊΠ°Π²Π΅ΠΎΠ»ΠΈΠ½ CAV1, Π²ΡΡΠ²Π»Π΅Π½ΠΎ ΡΡΠ°ΡΠΈΡΡΠΈΡΠ΅ΡΠΊΠΈ Π΄ΠΎΡΡΠΎΠ²Π΅ΡΠ½ΠΎΠ΅ ΡΠ°Π·Π»ΠΈΡΠΈΠ΅ Π² ΡΠ°ΡΡΠΎΡΠ΅ Π²ΡΡΡΠ΅ΡΠ°Π΅ΠΌΠΎΡΡΠΈ ΠΌΠΈΠ½ΠΎΡΠ½ΠΎΠ³ΠΎ Π°Π»Π»Π΅Π»Ρ, ΠΏΡΠΈ ΡΡΠΎΠΌ Π΄Π°Π½Π½ΡΠΉ Π³Π΅Π½ΠΎΡΠΈΠΏ ΠΎΠΊΠ°Π·ΡΠ²Π°Π΅Ρ ΠΏΡΠΎΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΠ΅ Π΄Π΅ΠΉΡΡΠ²ΠΈΠ΅ Π² ΠΎΡΠ½ΠΎΡΠ΅Π½ΠΈΠΈ ΡΠ°Π·Π²ΠΈΡΠΈΡ Π°ΡΠΈΡΠΌΠΈΠΈ (OR=0,39).
ΠΠ°ΠΊΠ»ΡΡΠ΅Π½ΠΈΠ΅. ΠΠΎΠ»ΡΡΠ΅Π½Π½ΡΠ΅ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΡ ΠΏΠΎΠΊΠ°Π·Π°Π»ΠΈ Π²Π·Π°ΠΈΠΌΠΎΡΠ²ΡΠ·Ρ ΠΌΠ΅ΠΆΠ΄Ρ ΠΏΠΎΠ»ΠΈΠΌΠΎΡΡΠ½ΡΠΌΠΈ ΠΌΠ°ΡΠΊΠ΅ΡΠ°ΠΌΠΈ Π³Π΅Π½ΠΎΠ² PITX2 (rs2200733; OR=3,18 p0,0001), PRRX1 (rs3903239; OR=2,96, p0,0001) ΠΈ ZFHX3 (rs2106261; OR=2,02, p=0,045 ΠΈ rs 7193343, OR=1,64, p=0,04), ΠΊΠΎΠ΄ΠΈΡΡΡΡΠΈΡ
ΡΠ°ΠΊΡΠΎΡΡ ΡΠ΅Π³ΡΠ»ΡΡΠΈΠΈ ΡΡΠ°Π½ΡΠΊΡΠΈΠΏΡΠΈΠΈ, ΠΈ ΡΠ°Π·Π²ΠΈΡΠΈΠ΅ΠΌ ΡΠΈΠ±ΡΠΈΠ»Π»ΡΡΠΈΠΈ ΠΏΡΠ΅Π΄ΡΠ΅ΡΠ΄ΠΈΠΉ. ΠΠ΄Π½Π°ΠΊΠΎ ΠΎΡΡΠ°ΡΡΡΡ ΠΎΡΠΊΡΡΡΡΠΌΠΈ Π²ΠΎΠΏΡΠΎΡΡ, ΠΊΠ°ΠΊΠΈΠΌ ΠΎΠ±ΡΠ°Π·ΠΎΠΌ ΡΡΠΈ ΠΏΠΎΠ»ΠΈΠΌΠΎΡΡΠ½ΡΠ΅ ΠΌΠ°ΡΠΊΠ΅ΡΡ Π²Π»ΠΈΡΡΡ Π½Π° ΡΡΠ½ΠΊΡΠΈΠΈ Π³Π΅Π½ΠΎΠ² ΠΈ, ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²Π΅Π½Π½ΠΎ, ΠΊΠ°ΠΊΠΎΠΉ ΠΏΠΎΠ΄Ρ
ΠΎΠ΄ ΠΏΡΠΈ ΠΊΠΎΡΡΠ΅ΠΊΡΠΈΠΈ ΡΠΎΡΡΠΎΡΠ½ΠΈΡ ΠΏΠ°ΡΠΈΠ΅Π½ΡΠ° Ρ ΡΠΈΠ±ΡΠΈΠ»Π»ΡΡΠΈΠ΅ΠΉ ΠΏΡΠ΅Π΄ΡΠ΅ΡΠ΄ΠΈΠΉ Π±ΡΠ΄Π΅Ρ Π½Π°ΠΈΠ±ΠΎΠ»Π΅Π΅ ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΡΠΌ
Measurement of the Lambda(b) cross section and the anti-Lambda(b) to Lambda(b) ratio with Lambda(b) to J/Psi Lambda decays in pp collisions at sqrt(s) = 7 TeV
The Lambda(b) differential production cross section and the cross section
ratio anti-Lambda(b)/Lambda(b) are measured as functions of transverse momentum
pt(Lambda(b)) and rapidity abs(y(Lambda(b))) in pp collisions at sqrt(s) = 7
TeV using data collected by the CMS experiment at the LHC. The measurements are
based on Lambda(b) decays reconstructed in the exclusive final state J/Psi
Lambda, with the subsequent decays J/Psi to an opposite-sign muon pair and
Lambda to proton pion, using a data sample corresponding to an integrated
luminosity of 1.9 inverse femtobarns. The product of the cross section times
the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls
faster than that of b mesons. The measured value of the cross section times the
branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.06
+/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for
anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are
statistical and systematic, respectively.Comment: Submitted to Physics Letters
Age data on pegmatites of south Kerala and their tectonic significance.
The K/Ar mica age of chrysoberyl-bearing pegmatites from four localities of Trivandrum district, Kerala, SW India, ranges 445- 474 m.y., with a mean of approx 460 m.y. Close agreement exists between the ages of the concordant and crosscutting pegmatites, between muscovite and biotite ages, and also between various size fractions. Chrysoberyl occurs within feldspars in association with quartz and muscovite. Since the formation of chrysoberyl-quartz association requires a higher P or T, the reported age would indicate the time of emplacement of the chrysoberyl-bearing pegmatites at the closing phase of a major tectonomagmatic event. It is interesting to note that these pegmatites are younger compared with those of other localities such as Rajasthan, Bihar, Nellore and Mysore. -T.R
AGE DATA ON PEGMATITES OF SOUTH KERALA AND THEIR TECTONIC SIGNIFICANCE
The K/Ar mica age of chrysoberyl-bearing pegmatites from four localities of Trivandrum district, Kerala, SW India, ranges 445- 474 m.y., with a mean of approx 460 m.y. Close agreement exists between the ages of the concordant and crosscutting pegmatites, between muscovite and biotite ages, and also between various size fractions. Chrysoberyl occurs within feldspars in association with quartz and muscovite. Since the formation of chrysoberyl-quartz association requires a higher P or T, the reported age would indicate the time of emplacement of the chrysoberyl-bearing pegmatites at the closing phase of a major tectonomagmatic event. It is interesting to note that these pegmatites are younger compared with those of other localities such as Rajasthan, Bihar, Nellore and Mysore. -T.R
Age data on pegmatites of south Kerala and their tectonic significance.
The K/Ar mica age of chrysoberyl-bearing pegmatites from four localities of Trivandrum district, Kerala, SW India, ranges 445- 474 m.y., with a mean of approx 460 m.y. Close agreement exists between the ages of the concordant and crosscutting pegmatites, between muscovite and biotite ages, and also between various size fractions. Chrysoberyl occurs within feldspars in association with quartz and muscovite. Since the formation of chrysoberyl-quartz association requires a higher P or T, the reported age would indicate the time of emplacement of the chrysoberyl-bearing pegmatites at the closing phase of a major tectonomagmatic event. It is interesting to note that these pegmatites are younger compared with those of other localities such as Rajasthan, Bihar, Nellore and Mysore. -T.R