Hypoxia and vascular endothelial growth factor expression in human squamous cell carcinomas using pimonidazole as a hypoxia marker

Hypoxia in human tumors is associated with poor prognosis, but the molecular mechanisms underlying this association are poorly understood. One possibility is that hypoxia is linked to malignant progression through vascular endothelial growth factor (VEGF) induction and the associated angiogenesis and metastasis. The present clinical study measures hypoxia and VEGF expression on a cell-by-cell basis in human squamous cell carcinomas to test the hypothesis that hypoxia and VEGF protein expression are coupled in human tumors. Eighteen patients with invasive squamous cell carcinoma of the uterine cervix and head and neck have been investigated by a quantitative image analysis of immunostained sections from their tumors. The hypoxia marker pimonidazole was used to measure tumor hypoxia, and a commercially available antibody was used to measure VEGF protein expression. A quantitative immunohistochemical comparison of hypoxia and VEGF protein expression revealed no correlation between the two factors.     

Inhibitors of branched-chain amino acid biosynthesis as potential antituberculosis agents

Previous studies have shown that rheumatoid arthritis aggregates within families. However, no formal genetic analysis of rheumatoid arthritis in pedigrees together with other autoimmune diseases has been reported. We hypothesized that there are genetic factors in common in rheumatoid arthritis and other autoimmune diseases. Results of odds-ratio regression and complex segregation analysis in a sample of 43 Caucasian pedigrees ascertained through a rheumatoid arthritis proband or matched control proband, revealed a very strong genetic influence on the occurrence of both rheumatoid arthritis and other autoimmune diseases. In an analysis of rheumatoid arthritis alone, only one inter-class measure, parent-sibling, resulted in positive evidence of aggregation. However, three inter-class measures (parent-sibling, sibling-offspring, and parent-offspring pairs) showed significant evidence of familial aggregation with odds-ratio regression analysis of rheumatoid arthritis together with all other autoimmune diseases. Segregation analysis of rheumatoid arthritis alone revealed that the mixed model, including both polygenic and major gene components, was the most parsimonious. Similarly, segregation analysis of rheumatoid arthritis together with other autoimmune diseases revealed that a mixed model fitted the data significantly better than either major gene or polygenic models. These results were consistent with a previous study which concluded that several genes, including one with a major effect, is responsible for rheumatoid arthritis in families. Our data showed that this conclusion also held when the phenotype was defined as rheumatoid arthritis and/or other autoimmune diseases, suggesting that several major autoimmune diseases result from pleiotropic effects of a single major gene on a polygenic background.     

Subject, project or self? Thoughts on ethical dilemmas for social and medical researchers

In this paper we address an important but sadly neglected area; namely some of the ethical issues which arise for social and medical researchers in the course of their work. Our concern is for a wide spectrum of researchers using the full range of social research methods from small-scale in-depth qualitative work through to large scale quantitative studies. The unifying factor is that they all have an element of contact and hence the potential for interaction between the researcher and the subject. In our experience (with the exception of some ethnographers) few if any social researchers will have had adequate training about the interactional aspects of their work. As a result they are unprepared for the ethical dilemmas and conflict of loyalties which they might experience. To understand these issues it is important to look at the context within which such research is undertaken.     

Levonorgestrel subdermal implants. A review of contraceptive efficacy and acceptability

Levonorgestrel 6-capsule subdermal implants (Norplant) are an effective form of reversible contraception. When implanted under the skin of the upper arm, they release drug into the circulation at a relatively constant rate over 5 years. Generally, the cumulative pregnancy rate at the end of 5 years' levonorgestrel implant use is less than 2 per 100 users. The implants provide contraceptive efficacy equivalent to, or better than, that provided by other reversible methods (including oral contraceptives). Younger women are more likely than older women to become pregnant while using levonorgestrel implants. Bodyweight was positively correlated with risk of pregnancy in a number of studies, but may not be a factor with the currently available 6-capsule implant formulation. Limited data suggest that a new 2-rod levonorgestrel subdermal system (Jadelle) is as effective as the more extensively studied 6-capsule system and has a similar tolerability profile. Fertility returns rapidly after the implants are removed. Use of levonorgestrel subdermal implants is compatible with breast-feeding. In several studies, discontinuation rates were 2 to 15% during the first year of use; cumulative 5-year discontinuation rates ranged from 22 to 64 per 100 women. Despite a substantial incidence of adverse events during therapy, levels of user satisfaction are generally high. Menstrual abnormalities (increased or decreased menstrual flow, spotting, irregularity and amenorrhoea) affect most women at some time during therapy and are the most frequent reason for discontinuing levonorgestrel implants before the end of 5 years' treatment (incidence of 4.2 to 30.7 per 100 users). Mood changes and headache also may lead to discontinuation. Other reported adverse events include skin reactions (including acne), dizziness and weight gain. Serious adverse events (such as stroke, thrombotic thrombocytopenia and idiopathic intracranial hypertension) have been reported during levonorgestrel implants therapy, but the population incidence is difficult to calculate and causality is unclear. According to 3 pharmacoeconomic analyses from an institutional or managedcare perspective, all contraceptive interventions result in net cost savings. It is not clear whether levonorgestrel implants provide greater or smaller economic benefits than combined oral contraceptives. CONCLUSION: Levonorgestrel subdermal implants provide effective long term contraception. Despite a high incidence of menstrual adverse events, overall levels of user satisfaction are high, and 1-year continuation rates are better than those for combined oral contraceptives. Levonorgestrel subdermal implants are a good choice of contraceptive method in women who desire effective contraception, but who are unable to, or prefer not to, comply with an oral regimen.     

Cecal volvulus as a complication in Cornelia de Lange syndrome. A case report and literature review

Colonic volvulus in children is a rare, but serious and important differential diagnosis in acute abdominal illness. Our patient with Cornelia de Lange's syndrome, was admitted with an acute onset of abdominal pain and in a critical condition. Explorative laparotomy revealed a caecal volvulus with necrosis of the distal ileum, caecum and proximal colon. The syndrome is characterized by typical facial expression, both growth and mental retardation, and various gastrointestinal and cardiac anomalies. Predisposing factors contributing to volvulus in this syndrome are mental retardation and a higher incidence of malrotation and nonfixation of the caecum and ascending colon. The parents of children with Cornelia de Lange's syndrome should therefore be counselled so that they are able to provide essential information in the event of their children experiencing acute illness.     

Genetic divergence and evolutionary instability in ospE-related members of the upstream homology box gene family in Borrelia burgdorferi sensu lato complex isolates

A series of related genes that are flanked at their 5' ends by a conserved upstream sequence element called the upstream homology box (UHB) have been identified in Borrelia burgdorferi. These genes have been referred to as the UHB or erp gene family. We previously demonstrated that among a limited number of B. burgdorferi isolates, the UHB gene family is variable in composition and organization. Prior to this report the UHB gene family in other species of the B. burgdorferi sensu lato complex had not been studied, and if this family is important in the pathogenesis or biology of the Lyme disease spirochetes, then a wide distribution among species and isolates of the B. burgdorferi sensu lato complex would be expected. To assess this, we screened for the UHB element by Southern hybridization and determined its restriction fragment length polymorphism (RFLP) patterns. The UHB element was found to be carried by all B. burgdorferi sensu lato complex species tested (B. burgdorferi, B. garinii, B. afzelii, B. japonica, B. valaisiana sp. nov., and B. andersonii), but the RFLP patterns varied widely at both the inter- and intraspecies levels. Variation in both the number and size of the hybridizing restriction fragments was evident. PCR analyses also revealed the presence of polymorphic, ospE-related alleles in many isolates. Sequence analyses identified the molecular basis of the polymorphisms as being primarily insertions and deletions. Sequence variation and the insertions and deletions were found to be clustered in two distinct domains (variable domains 1 and 2). In many isolates variable domain 1 is flanked by direct repeat elements, some as long as 38 bp. Computer analyses of the deduced amino acid sequences encoded within variable domain 1 predict them to be hydrophilic, surface exposed, and antigenic. The analyses conducted here suggest that the UHB gene family, as evidenced by the variable UHB RFLP patterns, is not evolutionarily stable and that the polymorphic ospE alleles are derived from a common ancestral gene which has been modified through mutation or recombination events. The characterization of ospE-related genes of the UHB gene family among B. burgdorferi sensu lato species will prove important in attempts to construct a model for UHB gene family organization and in deciphering the role of the UHB gene family in the biology and pathogenesis of the Lyme disease spirochetes.     

Langerhans' cell histiocytosis of the spine: use of MRI in guiding biopsy

The MRI features of two cases of spinal Langerhans' cell histiocytosis with multilevel involvement are presented in which MRI was of help in differentiating active from inactive healing lesions by the demonstration of signal changes in the vertebral body marrow of the active lesion, manifest as low signal intensity on T1-weighted sequences and high signal intensity on T2-weighted sequences. This distinction could not be made by plain radiography or bone scintigraphy. In cases where biopsy is required for diagnosis, MRI is recommended to guide the biopsy towards levels suggestive of active involvement.     

Root stimulation studies in the evaluation of patients with motor neuron disease

Nerve root stimulation may be employed in patients with motor neuron disease (MND) to rule out motor neuropathy with conduction block. The diagnostic utility of these studies is unknown, in part because the range of amplitude changes across nerve root segments in patients with active neuronal degeneration has not been well studied. We reviewed root stimulation studies in 32 patients (59 nerves) with MND and found segmental amplitude reduction from 0 to 45%, a range similar to values reported for normal subjects; there was no suggestion of conduction block based on our usual criteria.     

The CRY1 blue light photoreceptor of Arabidopsis interacts with phytochrome A in vitro

Plants have at least two major photosensory receptors: phytochrome (absorbing primarily red/far-red light) and cryptochrome (absorbing blue/UV-A light); considerable physiological and genetic evidence suggests some form of communication or functional dependence between the receptors. Here, we demonstrate in vitro, using purified recombinant photoreceptors, that Arabidopsis CRY1 and CRY2 (cryptochrome) are substrates for phosphorylation by a phytochrome A-associated kinase activity. Several mutations within the CRY1 C terminus lead to reduced phosphorylation by phytochrome preparations in vitro. Yeast two-hybrid interaction studies using expressed C-terminal fragments of CRY1 and phytochrome A from Arabidopsis confirm a direct physical interaction between both photoreceptors. In vivo labeling studies and specific mutant alleles of CRY1, which interfere with the function of phytochrome, suggest the possible relevance of these findings in vivo.