The last order of coiling in human chromosomes

The dimensions of chromatids in vivo and in fixed preparations of human chromosomes from cultured lymphocytes were compared. The relative variation in diameter in relation to length was the same in both conditions, but the lengths of the fixed chromosomes were about twice that of the chromosomes in vivo. The last order of coiling was studied in fixed chromosomes and in prematurely condensed chromosomes. The pitch of the coils in the fixed chromosomes, 0.6 μm, was independent of haploid length in the interval 90–220 μm. A clear indication of a spiralization of an underlying fibre was found throughout the haploid length interval of the prematurely condensed chromosomes, which ranged from 130 μm to more than 350 μm.     

Preovulatory plasma estradiol-17beta concentrations and ovulation rates in PMSG/anti-PMSG treated heifers

Possibilities for early characterization of the superovulatory response were studied in 41 PMSG/PG-treated dairy heifers, of which 21 received an additional treatment of PMSG-antiserum. Plasma was obtained at 33, 36, 41, 47 and 51 h after PG for hormone analyses. After slaughter at 6 or 7 d after insemination, the number of follicles and corpora lutea (CL) were recorded, and ova were recovered for morphological evaluation. Significant correlations were demonstrated between plasma concentrations of estradiol-17beta (E2) at 33, 36 and 41 h after PG and the ovulation rate (number of CL). Each of these correlations was equal to the one found by using the peak concentration of E2 achieved during the preovulatory E2 surge. In heifers with preovulatory E2 surges, as determined with the blood sampling scheme used, both the ovarian response (number of CL and follicles) and the quality of ova recovered (number of transferable embryos) was clearly better compared to heifers without this surge. None of the parameters studied was affected significantly by treatment with PMSG-antiserum. It is concluded that plasma E2 determinations at fixed times in relation to prostaglandin treatment can be used to characterize the superovulatory response in donor cattle in terms of the ovulation rate and the quality of ova recovered. No evidence was found in favor of using PMSG-antiserum for improving either the superovulatory response or such characterization.     

Demonstration of Neuron-Glia Transfer of Precursors for Gaba Biosynthesis in a Co-Culture System of Dissociated Mouse Cerebral Cortex

Co-cultures of neurons and astrocytes were prepared from dissociated embryonic mouse cerebral cortex and cultured for 7 days. To investigate if these cultures may serve as a functional model system to study neuron-glia interaction with regard to GABA biosynthesis, the cells were incubated either in media containing [U-¹³C]glutamine (0.1, 0.3 and 0.5 mM) or 1 mM acetate plus 2.5 mM glucose plus 1 mM lactate. In the latter case one of the 3 substrates was uniformly ¹³C labeled. Cellular contents and ¹³C labeling of glutamate, GABA, aspartate and glutamine were determined in the cells after an incubation period of 2.5 h. The GABA biosynthetic machinery exhibited the expected complexity with regard to metabolic compartmentation and involvement of TCA cycle activity as seen in other culture systems containing GABAergic neurons. Metabolism of acetate clearly demonstrated glial synthesis of glutamine and its transfer to the neuronal compartment. It is concluded that this co-culture system serves as a reliable model in which functional and pharmacological aspects of GABA biosynthesis can be investigated. Special issue article in honor of Dr. Anna Maria Giuffrida-Stella. An erratum to this article can be found at     

Wogonin induces apoptosis by suppressing E6 and E7 expressions and activating intrinsic signaling pathways in HPV-16 cervical cancer cells

Wogonin is a flavonoid compound extracted from Scutellaria baicalensis and is well known as a benzodiazepine receptor ligand with anxiolytic effects. Many recent studies have demonstrated that wogonin modulates angiogenesis, proliferation, invasion, and tumor progress in various cancer tissues. We further explored the mechanism of action of wogonin on cervical cancer cells that contain or lack human papillomavirus (HPV) DNA. Wogonin was cytotoxic to HPV 16 (+) cervical cancer cells, SiHa and CaSki, but not to HPV-negative cells. We demonstrated that wogonin induced apoptosis by suppressing the expressions of the E6 and E7 viral oncogenes in HPV-infected cervical cancer CaSki and SiHa cells. The modulation of p53 and protein retinoblastoma (pRb) were also triggered by the suppression of E6 and E7 expressions. However, p53 was not altered in HPV-negative cervical cancer C33A cells. Moreover, wogonin modulated the mitochondrial membrane potential and the expression of pro- and anti-apoptotic factors such as Bax and Bcl-2. Wogonin also provoked the cleavage of caspase-3, caspase-9, and poly ADP ribose polymerase. After transfection of siRNAs to target E6 and E7, additional restoration of p53 and pRb was not induced, but processing of caspases and PARP was increased compared with wogonin treatment alone. Together, our findings demonstrated that wogonin effectively promotes apoptosis by downregulating E6 and E7 expressions and promoting intrinsic apoptosis in human cervical cancer cells.     

Diagnostic imaging and histologic background of nipple discharge -- our experience with 40 patients

The authors present the diverse etiology of nipple discharge, which background may be a tumor. They discuss the checkup ways of nipple discharge and review in detail the galactographic technique and evaluation. The examination of pathologic nipple discharge is essentially based on contact cytology, x-ray-, and ultrasound mammography. Consequently, galactography is applied by filling the ducts with contrast material. The final diagnosis is rendered by histologic examination, following the operation. The authors demonstrate the application and role of galactography through various cases.     

The reproductive biology of closely related coral species: gametogenesis in<Emphasis Type="Italic"> Madracis</Emphasis> from the southern Caribbean

Reproductive patterns were studied in closely related coral species of the genus Madracis on Curaçao, Netherlands Antilles. Gonadal development of six sympatric species was examined over a 13-month period. Reproductive differences among Madracis species are small. All species are hermaphroditic brooders and show similar patterns in gamete development. Timing of gamete maturation is positively correlated with seawater temperature in all species. Oocyte development typically begins in June and precedes the development of spermaries. Mature gametes, male and female, are present from August to November when seawater temperatures reach their yearly maximum. Developmental pathways for male and female gametes are identical among species. Interspecific differences exist in the number and size of oocytes. Our data indicates that differences in gametogenic development between closely related, but ecologically different subspecies are small or absent and do not necessarily match with species separations based on morphological criteria.Communicated by Topic Editor D. Barnes     

Bacterial Disproportionation of Elemental Sulfur Coupled to Chemical Reduction of Iron or Manganese

A new chemolithotrophic bacterial metabolism was discovered in anaerobic marine enrichment cultures. Cultures in defined medium with elemental sulfur (S⁰) and amorphous ferric hydroxide (FeOOH) as sole substrates showed intense formation of sulfate. Furthermore, precipitation of ferrous sulfide and pyrite was observed. The transformations were accompanied by growth of slightly curved, rod-shaped bacteria. The quantification of the products revealed that S⁰ was microbially disproportionated to sulfate and sulfide, as follows: 4S⁰ + 4H₂O → SO₄^2- + 3H₂S + 2H⁺. Subsequent chemical reactions between the formed sulfide and the added FeOOH led to the observed precipitation of iron sulfides. Sulfate and iron sulfides were also produced when FeOOH was replaced by FeCO₃. Further enrichment with manganese oxide, MnO₂, instead of FeOOH yielded stable cultures which formed sulfate during concomitant reduction of MnO₂ to Mn²⁺. Growth of small rod-shaped bacteria was observed. When incubated without MnO₂, the culture did not grow but produced small amounts of SO₄^2- and H₂S at a ratio of 1:3, indicating again a disproportionation of S⁰. The observed microbial disproportionation of S⁰ only proceeds significantly in the presence of sulfide-scavenging agents such as iron and manganese compounds. The population density of bacteria capable of S⁰ disproportionation in the presence of FeOOH or MnO₂ was high, > 10⁴ cm^-3 in coastal sediments. The metabolism offers an explanation for recent observations of anaerobic sulfide oxidation to sulfate in anoxic sediments.