Aluminum fluoride activation of bovine transducin induces two distinct conformational changes in the alpha subunit

We have used resonance energy transfer to read out the interactions of the alpha subunit of transducin (alpha T) with the transducin beta gamma subunit complex (beta gamma T) and to compare the rate of aluminum fluoride-induced alpha T activation, as reflected by the enhancement of the alpha T tryptophan fluorescence, with the rate for the dissociation of holotransducin into its component subunits. Specifically, a beta gamma T complex that was labeled with 5-(iodoacetamido)fluorescein (IAF-beta gamma T) served as a donor for resonance energy transfer and an alpha T-GDP species labeled with eosin 5-isothiocyanate (EITC-alpha TGDP) served as the acceptor. The quenching of IAF-beta gamma T fluorescence emission by the addition of the EITC-alpha TGDP species, due to resonance energy transfer between the IAF and EITC moieities, ranged from 10% to 15%. The association of the transducin subunits was rapid (i.e., within the time period of mixing) and dose-dependent, yielding an apparent Kd of approximately 150 nM for the alpha TGDP/beta gamma T interaction. Unexpectedly, we find that the dissociation of IAF-beta gamma T from an aluminum fluoride-activated alpha TGDP/IAF-beta gamma T complex occurs prior to the onset of the intrinsic fluorescence changes in alpha T that accompany activation of this subunit. Thus, there are at least two structural changes in alpha T that result from the occupation of the gamma-phosphate position in the nucleotide binding cleft of alpha T by aluminum fluoride.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of steroid hormones in potentiating transformation of cervical cells by human papillomaviruses

Human papillomaviruses (HPVs) are etiologically involved in cervical neoplasia, and epidemiological evidence suggests that steroid hormones can increase the risk of this cancer in HPV-infected women. Steroids can interact with hormone-response elements in the viral long control region, enhancing HPV transcription and resulting in transformation of cervical cells. Subsequent malignant progression may involve virus-induced chromosomal instability, facilitating viral DNA integration and deregulation of gene expression.

Multiple human papillomavirus type 16 glucocorticoid response elements functional for transformation, transient expression, and DNA-protein interactions

We have previously shown that human papillomavirus type 16 (HPV-16) can efficiently transform primary baby rat kidney cells in the presence of the steroid hormones progesterone and the glucocorticoid dexamethasone. To study this effect of hormone, different combinations of the previously identified glucocorticoid response element (GRE) at nucleotide 7640 of HPV-16 and the other two GREs that we have recently identified, at nucleotides 7385 and 7474, were mutated. The previously described GRE and the other two GREs were shown to be functional for the induction of transformation by dexamethasone. In addition, transient assays in cervical HeLa cells demonstrated the functional importance of the three individual GREs. Assays for in vitro interaction demonstrated the specific binding of a 97-kDa protein, the glucocorticoid receptor, to both recently identified HPV-16 GREs.

Human papillomavirus type 16 expression in cervical keratinocytes: role of progesterone and glucocorticoid hormones

OBJECTIVE

To determine the role of the steroid hormones, progesterone and glucocorticoids, and the viral hormone response elements, in the episomal expression of human papillomavirus (HPV) type 16 in primary human ectocervical cells.

METHODS

In situ hybridization and mutagenesis were used to assess the requirements of these hormones and the HPV 16 glucocorticoid/progesterone response elements in the induction of HPV 16 expression in ectocervical cells.

RESULTS

The assays detected a marked increase in viral messenger RNA only after treatment of the cells with either of the steroid hormones. This response was inhibited by the anti-progestin RU 486 in a concentration-dependent manner. Mutagenesis of the previously identified hormone response element in the regulatory region of the HPV 16 genome had no effect on hormone-induced HPV gene expression. We have now identified two additional hormone response elements. Different combinations of mutations in the three hormone response elements showed that all three were independently sufficient for the hormone-mediated induction of viral transcription.

CONCLUSIONS

Steroid hormones induce HPV 16 gene expression in cervical keratinocytes directly through three hormone response elements in the regulatory region of the viral genome. The anti-progestin RU 486 inhibits this induction. Because the physical state of HPV DNA in this in vitro system and in premalignant cervical lesions is extrachromosomal, steroid hormones may have a critical role in modulating HPV expression in such lesions.

Physical and sexual growth pattern of affluent Indian children from 5 to 18 years of age

The present study was conducted to study growth parameters on 12,899 boys and 9,951 girls of affluent class from 8 States of the country. In pooled data, the 50th centile height approached 30-40th centile till 6 1/2 years in boys and up to 10 years in girls, and ultimately the height growth curves for both fell between the 10-20th centile of NCHS standards. Similarly, for weight, they approached 10-20th centile of NCHS at the age of 17 yr. Comparison with other European countries showed that Indian affluents are shorter and lighter; however, they are similar to their counterparts of Asian origin. The secular trend for height in Delhi showed increase of 2.1 cm for boys, and 2.7 cm for girls per decade at 17 yr and 14 yr, respectively. In Varanasi, the corresponding trend was 1.5 and 2.1 cm at 16 yr for boys and girls, respectively. The mean ages for genital development stages G 2-5 were 11.9, 13.3, 14.6 and 15.9 yr; respectively. In girls, the breast development Stages B 2-5 had mean ages of 10.9, 12.8, 13.9 and 14.8 yr, respectively. The mean age for menarche was 12.6 yr. In 14 yr old boys, the mean height may vary between 150.3, 155.8, 161.2 and 165.2 cm and mean weight between 38.0, 42.5, 46.8 and 52.9 kg for genital stages G 2-5, respectively. Similarly, girls of 12.5 yr (close to menarcheal age of 12.6 yr) had mean height 145.3, 150.3, 152.1 and 153.8 cm and mean weight 34.7, 41.2, 45.4 and 54.4 kg for breast stages B 2-5, respectively. It is recommended that for growth assessment during adolescence these charts in relation to sexual development and age be used for comparison.

Enhanced siderophore production and mouse kidney pathogenicity in Escherichia coli grown in urine

Fifteen siderophore producing urinary isolates of Escherichia coli were compared for aerobactin and enterochelin production in trypticase soy broth and pooled normal human urine. Significant increase in siderophore production (both phenolate and hydroxamate) was observed when organisms were grown in urine. Mouse kidney pathogenic potential of the strains grown in urine was compared with that of bacteria grown in trypticase soy broth in an ascending model of pyelonephritis in female Swiss Webster mice. Organisms grown in urine and instilled into a mouse bladder demonstrated markedly enhanced renal pathogenicity (p less than 0.01). Further information about the influence of urinary constituents on siderophore production could help in understanding the pathogenesis of pyelonephritis.

Altered hemolysin production in urine-grown uroisolates of Escherichia coli

Fifteen uroisolates of E. coli were studied for both cell-free and cell-bound hemolysin production. Estimations were done in Trypticase soy broth (TSB, providing iron-replete medium) TSB + 2,2'-bipyridine (providing experimentally created iron-depleted conditions) and pooled normal human urine (providing natural iron-depleted growth medium). In TSB 40% of strains showed no detectable cell-free hemolysin, they were able to produce it in the presence of 2,2'-bipyridine and more so when grown in urine. The cell-bound hemolysin was produced by all the strains in TSB, but in the presence of 2,2'-bipyridine and urine an insignificant increase was observed. All the strains when given 2nd and 3rd passage in urine, were found to elaborate significantly more cell-free as well as cell-bound hemolysin.

Small cell lung cancer presenting as Cushing's syndrome

A rare case of small cell carcinoma of the lung who presented with Cushing's syndrome and superior vena cava syndrome is described. The relevant literature is reviewed.

Degrees of cooperativity between triiodothyronine and hydrocortisone in their regulation of the expression of myelin basic protein and proteolipid protein during brain development

Cultures of cells dissociated from embryonic mouse cerebra were used to demonstrate: (1) that the developmental expression of the mRNA of proteolipid protein is dependent on thyroid hormone; (2) that the expression of the mRNA of proteolipid protein is stimulated not only by triiodothyronine but also by hydrocortisone, which achieve their respective stimulations by an additive and uncompetitive mechanism; (3) the stimulation of the net accumulation of the mRNA of myelin basic protein by hydrocortisone and triiodothyronine is also cooperative, additive, and uncompetitive, and (4) the stimulation of the net accumulation of myelin basic protein, during development by hydrocortisone, is completely dependent on the presence of thyroid hormone. These results suggest that the regulation of the synthesis of myelin basic protein by hydrocortisone requires the presence of triiodothyronine at a posttranscriptional event, but not for transcription itself.

Generalized muscular pseudohypertrophy in cysticercosis

A 32 year old male Hindu, presenting with generalized muscular hypertrophy (Veritable Hercules), together with subcutaneous nodules and epilepsy, due to cysticercosis is described.