Endometrial fluid collection in women with hydrosalpinx after human chorionic gonadotrophin administration: a report of two cases and implications for management

The impact of hydrosalpinx (HSPX) on in-vitro fertilization (IVF) outcome has recently been the subject of intense debate. Most, but not all, studies have reported decreased implantation and pregnancy rates and increased early pregnancy loss in HSPX patients. This has led to prophylactic salpingectomies prior to IVF in HSPX patients despite the lack of any prospective studies to suggest that any improvement will occur. Women with HSPX constitute a heterogeneous population because some conceive easily with IVF while others do not until after surgical correction. HSPX also increases in size with ovarian stimulation, and can cause implantation failure by fluid reflux into the uterine cavity. Careful assessment of the endometrial lining is mandatory in HSPX to rule out fluid reflux from the HSPX. We present two case reports of patients whose HSPX enlarged with ovarian stimulation, causing fluid reflux into the uterine cavity which was only noted after human chorionic gonadotrophin (HCG) administration.     

Inhibitory effect of crocetin on intracellular nucleic acid and protein synthesis in malignant cells

The possibility that dietary intake of diverse naturally occurring compounds may influence the occurrence of cancer is receiving considerable scientific attention. Previously, it was reported that an extract (Crocus sativus), which contains carotenoids, had an antitumor effect and inhibited colony formation and nucleic acid synthesis by malignant human cells. Epidemiological and experimental research has indicated that carotenoids might act as antitumor agents. We have studied crocetin, a carotenoid isolated from saffron, which has been shown to have biological activity. In our experiments we utilized three malignant human cell lines: HeLa (cervical epitheloid carcinoma), A549 (lung adenocarcinoma) and VA13 (SV-40 transformed fetal lung fibroblast) cells. The effect of crocetin on colony formation and cellular DNA, RNA and protein synthesis in these cells has been examined. Incubation of these cells with crocetin for 3 h caused a dose-dependent inhibition of nucleic acid and protein synthesis. Crocetin also had a dose-dependent inhibitory effect on DNA and RNA synthesis in isolated nuclei and suppressed the activity of purified RNA polymerase II.     

Spectral analysis of electrocardiogram signals of the isolated guinea pig heart for the detection of arrhythmias

Fast Fourier Transform analysis of the electrocardiogram (ECG) signal of the isolated guinea pig heart has been used to investigate the subtle ECG changes that precede cardiac arrhythmias. During prolonged periods of regular contractile activity, spectral analysis of the isolated guinea pig heart ECG revealed that the major frequency components were evenly distributed over the range 0-64 Hz. Prior to arrhythmias or during ischaemia however, there was a major reduction in the amplitude of the higher frequency components. Thus, Fast Fourier Transform analysis of an ECG record enables the detection of the subtle ECG configuration changes that precede cardiac rhythm disturbances. The potential application of this technique for the prediction of cardiac arrhythmias is discussed.     

The nature and use of purified insulins

The limited availability of highly purified insulin preparations for the treatment of diabetes mellitus in australia since 1975, has prompted a review of their history, clinical use and potential in the treatment of diabetics receiving insulin.     

Chemical nature of the light emitter of the Aequorea green fluorescent protein

The jellyfish Aequorea victoria possesses in the margin of its umbrella a green fluorescent protein (GFP, 27 kDa) that serves as the ultimate light emitter in the bioluminescence reaction of the animal. The protein is made up of 238 amino acid residues in a single polypeptide chain and produces a greenish fluorescence (lambda max = 508 nm) when irradiated with long ultraviolet light. The fluorescence is due to the presence of a chromophore consisting of an imidazolone ring, formed by a post-translational modification of the tripeptide -Ser65-Tyr66-Gly67-. GFP has been used extensively as a reporter protein for monitoring gene expression in eukaryotic and prokaryotic cells, but relatively little is known about the chemical mechanism by which fluorescence is produced. To obtain a better understanding of this problem, we studied a peptide fragment of GFP bearing the chromophore and a synthetic model compound of the chromophore. The results indicate that the GFP chromophore consists of an imidazolone ring structure and that the light emitter is the singlet excited state of the phenolate anion of the chromophore. Further, the light emission is highly dependent on the microenvironment around the chromophore and that inhibition of isomerization of the exo-methylene double bond of the chromophore accounts for its efficient light emission.