Light and electron microscopic study on thyroxine-induced in vitro resorption of the tadpole tail fin

Summary Tail fin pieces (discs) of Rana pipiens tadpoles were treated with thyroxine (T₄) solution (50 g/liter) and the induced changes were studied with the light and electron microscopes. Definitive effects first appeared after 4 days of treatment. Thereafter various resorptive processes proceeded at an accelerating pace. By the 9th or 10th day the discs were reduced to tiny spherules.The most conspicuous changes were those of the breakdown and disposal of the basement lamella. First there was a loosening of the collagen layers followed by massive infiltration by macrophages which engulfed the collagen fibrils. By the 8th day the phagocytosis of the basement lamella was completed for the most part and the macrophages were clumped into masses.After 6 days of T₄ treatment the epidermis was transformed from a 2- or 3-cell layered epithelium to a multilayered one. This was due to the detachment of the basal epithelial cells from the basement lamella followed by their movement towards the surface. Later, the epidermal cells showed atrophy by extensive autolytic processes.Discs incubated in the control medium (devoid of T₄) remained intact for the duration of the experiment. Their morphology was essentially the same as that described by others from studies in vivo.This study was supported by Grants NIH T1-GM-102, NSF GB-5913, NIH NB-00840 and NIH NB-07566, and an Institutional Grant from the New Jersey College of Medicine and Dentistry.I am indebted to Drs. J. Osinchak and W. Etkin for their encouragement.     

Prevalence of Human Papillomavirus Genotypes among African Women with Normal Cervical Cytology and Neoplasia: A Systematic Review and Meta-Analysis

Background

Several meta-analyses confirmed the five most prevalent human papillomavirus (HPV) strains in women with and without cervical neoplastic diseases are HPV16, 18, 31, 52, and 58. HPV16/18 are the predominant oncogenic genotypes, causing approximately 70% of global cervical cancer cases. The vast majority of the women studied in previous analyses were from Europe, North America, Asia, and most recently Latin America and the Caribbean. Despite the high burden of cervical cancer morbidity and mortality in Africa, a robust meta-analysis of HPV genotype prevalence and distribution in African women is lacking.

Methods and Findings

We systematically searched 14 major databases from inception to August 2013 without language restriction, following the Meta-Analysis of Observational Studies in Epidemiology and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Seventy-one studies from 23 African countries were identified after screening 1162 citations and data abstracted and study quality appraised from 195 articles. HPV type-specific prevalence and distribution was estimated from 17,273 cases of women with normal cervical cytology; 1019 women with atypical squamous cells of undetermined significance (ASCUS); 1444 women with low-grade squamous intraepithelial lesion (LSIL); 1571 women with high-grade squamous intraepithelial lesion (HSIL); and 4,067 cases of invasive cervical carcinoma (ICC). Overall prevalence of HPV16/18 were 4.4% and 2.8% of women with normal cytology, 12.0% and 4.4% with ASCUS, 14.5% and 10.0% with LSIL, 31.2% and 13.9% with HSIL, and 49.7% and 18.0% with ICC, respectively. Study limitations include the lack of adequate data from Middle and Northern African regions, and variations in the HPV type-specific sensitivity of different genotyping protocols.

Conclusions

To our knowledge, this study is the most comprehensive assessment of the overall prevalence and distribution of HPV genotypes in African women with and without different cervical neoplasias. We have established that HPV16/18 account for 67.7% of ICC cases among African women. Based on our findings, we highly recommend the administration of existing prophylactic vaccines to younger women not infected with HPV16/18 and an increase in HPV screening efforts for high-risk genotypes to prevent cervical cancer. Review registration: International Prospective Register of Systematic Reviews CRD42013006558.     

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) induced mitochondrial pathway to apoptosis and caspase activation is potentiated by phospholipid scramblase-3

Tumor Necrosis Factor (TNF)-Related Apoptosis-Inducing Ligand (TRAIL) initiate pathways of cell death in which caspase activation is mediated either directly (without mitochondrial amplification), or indirectly via the release of apoptogenic factors from mitochondria. Phospholipid scramblases (PLS) are enzymes that play a key role in cellular function by inducing bidirectional movement of membrane lipids. Changes in mitochondrial membrane lipids, cardiolipin, are critical for mediating apoptotic response in many cell-types. PLS3 is a phospholipid scramblase that is localized to mitochondria and is thought to be involved in the regulation of apoptotic signals. Here we report that exogenous-expression of PLS3 enhances apoptotic death induced by TRAIL. This is acheived by potentiating the mitochondrial arm of the death pathway. Thereby, PLS3 expression facilitates changes in mitochondrial membrane lipids that promote the release of apoptogenic factors and consequent full activation and processing of the caspase-9 and effector caspase-3. Moreover, we show that knock-down of endogenous PLS3 suppresses TRAIL-induced changes in cardiolipin. Finally, we demonstrate that TRAIL-induced activation of PKC-delta mediates regulation of the PLS3-induced changes in cardiolipin.     

Prolactin and ergocryptine effects on mucus glycoproteins of the rat ileum

Summary The present work reports observations from a first study on the effect of prolactin on mucous cells of the mammalian ileum. Sprague-Dawley rats were treated with prolactin or with the prolactin-inhibitor ergocryptine. Light microscopic histochemical study revealed that ergocryptine increased the number both of Alcian Blue-positive mucous cells and of the total number of mucous cells in the ileal crypts. Prolactin treatment apparently decreased the number of Alcian Blue pH 1.0-positive (sulphated glycoprotein-containing) mucous cells on the villi but was without effect on crypt cells. The implications of these observations are discussed.     

Secondary somatic embryogenesis of carnation (<Emphasis Type="Italic">Dianthus caryophyllus</Emphasis> L.)

This is the first report describing culture conditions necessary to induce secondary embryogenesis in two carnation cultivars, Nelson and Spirit. In the first step, embryogenic calli were induced on petal explants followed by development of primary somatic embryos from the calli. In the second stage, secondary somatic embryos were obtained when precotyledonary and cotyledonary primary embryos were isolated and transferred onto a series of culture media all containing MS basal salt mixture, and supplemented with different concentrations of 2,4-D, BA, sucrose and mannitol. The highest rate of secondary embryogenesis occurred on mannitol containing media. Secondary somatic embryos were converted into plantlets when they were transferred onto growth regulator-free half-strength MS medium and successfully acclimated in the greenhouse.