Biomedical subjects
Publications and source records attributed to I M Thomas.
For in vitro studies in mesentery, toluidine blue and thionin dyes are generally used. We have tried thionin and acridine orange stains and found it to be good as it showed good colour contrast between mast cells and the background tissue. The two dyes were selected to give good colour contrast.
Dermatoglyphics is known to be one of the best available diagnostic tools in genetic disorders. This paper aims to find out the diagnostic characteristic dermatoglyphic features in cytogenetically confirmed 46, XY female patients. The total number of patients studied (46, XY females) were 31 and the control consisted of 30 males and 30 females. Dermatoglyphic features, studied and tabulated, were: (a) Finger pattern frequency, (b) total finger ridge count (TFRC), absolute finger ridge count (AFRC), a-b ridge count, 'atd' angle and (c) palmar patterns eg, simian crease, Sydney line, hypothenar pattern, interdigital patterns. Results confirmed significant differences between the 46, XY females and the control groups: (i) 46, XY females had increased ulnar loops but decreased whorls as compared to control males (overall finger pattern frequency). (ii) The right thumb in 46, XY females had less whorls and more ulnar loops than both male and female control groups (individual finger pattern frequency). (iii) 46, XY females had lowered TFRC, AFRC, a-b ridge count than corresponding control groups (both control males and females). Significant differences were not observed for the 'atd' angle, interdigital patterns, hypothenar pattern, simian crease and Sydney line.
Haemophilia in a female is very rare. We report a case of haemophilia in a female with a male sex chromosome pattern.
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Two female patients aged 16 and 17 years with Turner features short stature, amenorrhea and gonadal dysgenesis were referred for cytogenetic confirmation and counselling. Their karyotypes were 46, X, dup (X) (q13-->q22). The clinical and the cytogenetic picture have been correlated.
The effect of consanguinity on the non-disjunction mechanism in Down's syndrome, was examined in 417 cytogenetically confirmed Down's syndrome patients. The incidence of parental and grandparental consanguinity was 17.5% (n = 73), while that of only parental consanguinity was 17.2% (n = 71). First cousin marriages occurred more frequently, than uncle-niece and 2nd cousin marriages. With regard to parental age, only the mean age difference between consanguineous couples significantly differed from non-consanguineous couples. The inbreeding coefficient did not differ between trisomy 21 and translocation Down's families. From this study, it is concluded that consanguinity does not predispose to Down's syndrome.
A simple design of a mobile embalming unit is presented that offers better quality embalming and is fairly economical. The technique is faster and consistently more reliable than the conventional gravity aided embalming.
Individuals with translocation Down syndrome (DS) often inherit the rearranged chromosome from a carrier parent. DS due to inheritance of one Robertsonian or derivative (14q21q) from one parent and a second der(14q21q) in addition to a free chromosome 21 from the other parent are rarely documented in liveborn infants. Presented here is such a propositus with DS and with a unique karyotype 45,XY,der(14;21) (p11.1;p11.1)pat,der(14;21)(p11.1;q11.1)mat, +21mat. Using conventional chromosome heteromorphisms, fluorescent in situ hybridization (FISH), and microsatellite polymorphism analyses, we established the biparental origin of the 2 der(14q21q) and the maternal origin of the extra chromosome 21 in the patient. A combination of both cytogenetic and molecular genetic techniques also enabled us to show that the 2 der(14q21q) were not identical by descent and hence the parents were nonconsanguineous. It has been a well-established fact that mothers with Robertsonian translocations have higher risk for nondisjunction than do carrier fathers. Our case, wherein the nondisjunctional event occurred in the mother, even though both parents are carriers of a 14;21 Robertsonian translocation, is yet another example of this.
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This paper reports the associated malformations and the clinical findings that were observed in 417 cytogenetically confirmed Down Syndrome patients. Among them congenital heart defects have occurred more frequently [75; 17.98%] than osteoarticular malformations [23; 5.52]; eye anomalies [22; 5.27%]; and gastroenterological malformations [n 16; 3.84%]. With regard to prognosis and treatment appropriate counselling has been given to Down Syndrome patients and their families.
Dermatoglyphic data were obtained from 235 cytogenetically confirmed patients of Down's syndrome. The data were correlated and compared with 230 controls. Printing and transparent adhesive tape photography methods were used to get the dermatoglyphic prints. Patients' total finger ridge counts and 'atd' angles differed significantly from that of the controls. Mostly ulnar loop pattern was observed in the patients. Abnormal dermatoglyphic features such as, simian crease, Sydney line and patterns in the hypothenar and interdigital areas have occurred more frequently in the patients. Dermatoglyphics and the analyses carried out have proved that they are invaluable in their clinical value, in selecting patients of Down's syndrome for cytogenetic analysis.
The cervical spine x-rays of a random number of patients with confirmed rheumatoid arthritis were taken. The presence of atlanto-axial subluxation, atlanto-axial impaction, subaxial subluxation and any other associated abnormalities was noted. The spinal canal diameter was also measured which was not significantly altered in rheumatoid arthritis cases. Cervical spine disorders were seen to occur in 16 cases (69.6%) out of 23 patients. Spondylosis was the most frequent disorder ie, in 10 cases (62.5%) out of 16. Obliteration of the normal lordotic curve and disc lesions occurred in 3 cases (18.7%) each out of 16. The mean spinal canal diameter was 16.30 +/- 2 mm with a range of 13-23 mm. Female patients (73.3%) had an increased cervical spine disorder than males (62.5%). Seropositive rheumatoid arthritis cases (87.5%) were mostly involved in occurrence of disorder than those of seronegative arthritis cases (46%).
Total finger ridge count, absolute finger ridge count and finger print pattern were studied in 150 maturity onset diabetes mellitus patients and compared to 120 controls. Significant findings were: in males, with both hands combined and separately (i) an increase in radial and ulnar loops and arches (ii) A decrease in whorls. (iii) In females, an increase in ulnar loops and a decrease in whorls in the left hand was observed.
A male child with typical features of Down's syndrome and mosaicism of two trisomic cell lines, trisomy 18 (84%) and trisomy 21 (16%), is reported. Non-disjunction or anaphase lag of chromosomes 18 and 21 could be the cause.
We report measurements of slowly varying magnetic field patterns close to fertilized eggs of the chicken Gallus domesticus during the first few days of incubation. These fields are generated by ionic currents within the egg that are associated with the development of the embryo. Since they are very weak (no greater than tens of pT) and vary over distances of a few millimetres, it has been necessary to develop specialized instrumentation and analysis techniques. We describe the use of high-spatial-resolution SQUID magnetometers to measure the field patterns and appropriate imaging algorithms to model the current sources responsible for producing the fields. Our results provide strong evidence for a distributed source in the extra-embryonic membranes. There is also indication of a more localized source within the embryo itself.
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A case of t (1;21) in a 9-year-old female Down syndrome patient is reported. Her karyotype was 47,XX, t (1;21) (mat), +21. The father's karyotype was normal, while that of the mother was 46, XX, t (1;21). An amniotic fluid cell culture revealed a trisomy 21 and a t (1;21) in a male fetus. This is the first report of a familial case of trisomy 21 with t (1;21) from our country.
Poly (ADP-ribose) polymerase is a cellular repair enzyme synthesised following damage to DNA. 3-Aminobenzamide (3-AB) is an inhibitor of this repair enzyme. To study repair efficiency in leprosy patients, who usually show a significantly higher frequency of spontaneous chromosome aberrations and sister-chromatid exchanges (SCEs), their blood lymphocyte cultures were treated with 3-AB. A marginal increase in the frequency of chromosome aberrations was observed following treatment with 3-AB in controls as well as in patient groups. There was also no significant difference in the frequency of SCEs in control cultures with or without 3-AB. A significant increase in the frequency of SCEs was observed in lymphocyte cultures of paucibacillary (PB) and multibacillary (MB) patients treated with 3-AB when compared with controls. Observation of a significant increase in the frequency of SCEs in 3-AB-treated cultures over the untreated value indicates that DNA damage caused in leprosy patients following mycobacterial infection is not repaired because of the presence of the inhibitor of repair enzyme.