Crystal Structure, Bonding, and Phase Transition of the Superconducting Na2CsC60 Fulleride.

The crystal structure of superconducting Na(2)CsC(60) was studied by high-resolution powder neutron diffraction between 1.6 and 425 K. Contrary to the literature, the structure at low temperatures is primitive cubic [See equation in the PDF file], isostructural with pristine C(60). Anticlockwise rotation of the C(60) units by 98 degrees about [111] allows simultaneous optimization of C(60)-C(60) and alkali-fulleride interactions. Optimal Na(+)-C(60)(3-) coordination is achieved with each sodium ion located above one hexagon face and three hexagon-hexagon fusions of neighboring fulleride ions (coordination number 12). Reduction of the C(60) molecule lengthens the hexagon-hexagon fusions and shortens the pentagon-hexagon fusions (to approximately 1.43 angstroms). On heating, Na(2)CsC(60) undergoes a phase transition to a face-centered-cubic [See equation in the PDF file] phase, best modeled as containing quasi-spherical C(60)(3-) ions. The modified structure and intermolecular potential provide an additional dimension to the behavior of superconducting fullerides and should sensitively affect their electronic and conducting properties.

Significance of acquired nonrandom 7/14 translocations.

We have detected eight patients with a single metaphase having a 7/14 translocation. In all cases, the breakpoint on chromosome 14 was 14q12, while the breakpoint on chromosome 7 was 7q35 in three cases and 7p13 in five cases. The factors that may be involved in these nonrandom translocations are discussed.

Down syndrome with biparental inheritance of der(14q21q) and maternally derived trisomy 21: confirmation by fluorescent in situ hybridization and microsatellite polymorphism analysis.

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.

A distributed quasi-static ionic current source in the 3-4 day old chicken embryo.

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.

Chromosomal aberrations in tuberculosis patients before and after treatment with short-term chemotherapy.

Cytogenetic effects of 4 common anti-tubercular drugs, isoniazid (H), streptomycin (S), rifampicin (R) and pyrazinamide (Z), in 3 different combinations (2 SHRZ, 2 HRZ and 2 H2R2Z2) were evaluated in the lymphocytes of tuberculosis patients undergoing chemotherapy, in order to estimate their mutagenic potential in combination. All 3 regimens showed an increased frequency of chromosomal aberrations after treatment compared to before treatment. These findings are of significance in the treatment of tuberculosis, as the drugs in question are observed to be mutagenic/clastogenic.

Effect of inhibitor of poly (ADP-ribose) polymerase in blood lymphocyte cultures of untreated leprosy patients.

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.

Differential sensitivity of peripheral blood lymphocytes of untreated leprosy patients to mitomycin C.

The effects of a bifunctional alkylating agent mitomycin C (MMC), an effective inducer of chromosome aberrations and sister-chromatid exchanges (SCEs), have been studied in untreated leprosy patients. This was done to study the mutagen sensitivity of the leprosy patients. The frequency of chromosomal aberrations induced by MMC (conc. 0.01 microgram/ml) was 2.5% in controls, 3.6% in paucibacillary (PB), and 6.8% in multibacillary (MB) patients. The difference in the frequency of MMC-induced chromosome aberrations between the 3 groups studied was highly significant (p less than 0.01). Cultures grown with MMC showed the frequency of SCEs/cell to be 12.70 +/- 1.19 in controls, 19.97 +/- 3.51 in PB, and 29.66 +/- 5.92 in MB patients. The differences in the frequency of MMC-induced SCEs between the 3 groups were found to be highly significant (p less than 0.01). The enhanced frequencies of spontaneous and MMC-induced chromosome aberrations and SCEs observed in PB and MB patients indicate a clear differential mutagen sensitivity between PB and MB patients who are known to have different immunological status and thereby differ in the severity of the disease.

Cytogenetic investigations in Down syndrome patients & their parents.

A total of 1343 mentally retarded patients referred for cytogenetic evaluation were studied. Of these Down syndrome was confirmed in 365 (21.17%). There were 316 patients of trisomy 21 (86.58%); 21 of mosaicism (5.75%) and 28 of translocation (7.67%). Trisomy 21 patients with chromosomal variants were observed in 17 (4.65%). A 1.37:1 male:female ratio was seen. Karyotyping was also done on 182 parents (of patients of mosaic Down, translocation Down and trisomy 21 with chromosomal variants and in parents with suspected low mosaicism). Mosaic trisomy 21 cell line was found in one mother (0.27%); 6 parents (1.65%) were seen to be translocation carriers and 7 had chromosomal variants (1.92%). Cytogenetic investigations help to give appropriate genetic counselling to patients and their families.

Structural chromosomal anomaly in mental retardation.

This article reports the structural chromosomal anomaly in three patients with mental retardation: (i) Proband was a five year old girl with reciprocal retardation (1; 2) (p32; q11) (ii) Proband, female of 14 years. Her karyotype showed translocation (1; 3) (q42; q13). The translocations were de novo in origin (iii) Proband showed variant 13 as the giant satellite over its short arm, and this was paternal in origin. Proband, eighteen months old male child had microcephaly and seizures. These two features may be because of autosomal recessive condition. This report emphasises the need for kayotyping to provide a clear cut diagnosis and appropriate counselling.

Partial 1q and 21p trisomies in a male child due to maternal t(1;21).

Proband 7 years old male child referred for cytogenetic investigation revealed 47, XY + der (21), t(1;21) (q32;q11) mat.

Finger ridge count and finger print pattern in maturity onset diabetes mellitus.

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.

Down syndrome associated malformations.

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.

Primary amenorrhea with Xq duplication.

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.

A simple device for embalming cadavers.

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.

An unusual case of haemophilia--a case report.

Haemophilia in a female is very rare. We report a case of haemophilia in a female with a male sex chromosome pattern.

A modified thionin acridine-orange stain for mast cells.

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.

Menarche and menopause in Tamil Brahmins of India.

PIP: Age at menarche and menopause among the Tamil Brahmins of Bangalore, India, are analyzed using data on 295 women aged 25-70. Attention is given to the effect of consanguinity, socioeconomic status, family size, and birth order.^ieng