Daily sunscreen application and betacarotene supplementation in prevention of basal-cell and squamous-cell carcinomas of the skin: a randomised controlled trial

BACKGROUND

The use of sunscreens on the skin can prevent sunburn but whether long-term use can prevent skin cancer is not known. Also, there is evidence that oral betacarotene supplementation lowers skin-cancer rates in animals, but there is limited evidence of its effect in human beings.

METHODS

In a community-based randomised trial with a 2 by 2 factorial design, individuals were assigned to four treatment groups: daily application of a sun protection factor 15-plus sunscreen to the head, neck, arms, and hands, and betacarotene supplementation (30 mg per day); sunscreen plus placebo tablets; betacarotene only; or placebo only. Participants were 1621 residents of Nambour in southeast Queensland, Australia. The endpoints after 4.5 years of follow-up were the incidence of basal-cell and squamous-cell carcinomas both in terms of people treated for newly diagnosed disease and in terms of the numbers of tumours that occurred. Analysis of the effect of sunscreen was based only on skin cancers that developed on sites of daily application. All analyses were by intention to treat.

FINDINGS

1383 participants underwent full skin examination by a dermatologist in the follow-up period. 250 of them developed 758 new skin cancers during the follow-up period. There were no significant differences in the incidence of first new skin cancers between groups randomly assigned daily sunscreen and no daily sunscreen (basal-cell carcinoma 2588 vs 2509 per 100,000; rate ratio 1.03 [95% CI 0.73-1.46]; squamous-cell carcinoma 876 vs 996 per 100,000; rate ratio 0.88 [0.50-1.56]). Similarly, there was no significant difference between the betacarotene and placebo groups in incidence of either cancer (basal-cell carcinoma 3954 vs 3806 per 100,000; 1.04 [0.73-1.27]; squamous-cell carcinoma 1508 vs 1146 per 100,000; 1.35 [0.84-2.19]). In terms of the number of tumours, there was no effect on incidence of basal-cell carcinoma by sunscreen use or by betacarotene but the incidence of squamous-cell carcinoma was significantly lower in the sunscreen group than in the no daily sunscreen group (1115 vs 1832 per 100,000; 0.61 [0.46-0.81]).

INTERPRETATION

There was no harmful effect of daily use of sunscreen in this medium-term study. Cutaneous squamous-cell carcinoma, but not basal-cell carcinoma seems to be amenable to prevention through the routine use of sunscreen by adults for 4.5 years. There was no beneficial or harmful effect on the rates of either type of skin cancer, as a result of betacarotene supplementation.

Correlation of coronary calcification and angiographically documented stenoses in patients with suspected coronary artery disease: results of 1,764 patients

OBJECTIVES

This study correlated the electron beam computed tomographic (EBCT) calcium scores with the results of coronary angiography in symptomatic patients in order to assess its value to predict or exclude significant coronary artery disease (CAD).

BACKGROUND

Electron beam computed tomography is a sensitive method to detect coronary calcium. However, it is unclear whether it may play a role as a filter before invasive procedures in symptomatic patients.

METHODS

A total of 1,764 patients (1,225 men and 539 women) with suspected CAD from a single center were included in our study. All patients underwent calcium screening with EBCT (C150XP Imatron) and conventional coronary angiography.

RESULTS

Fifty-six percent of men and 47% of women revealed significant coronary stenoses (> or =50%). Total exclusion of coronary calcium (14% of the study group) was associated with an extremely low probability of stenosis (<1%). With calcium scores > or =20th, > or =100th or > or =75th percentile of age groups, the sensitivity to detect stenoses decreased to 97%, 93% and 81%, respectively, in men and to 98%, 82% and 76%, respectively, in women. At the same time, the specificity increased up to 77% in men and women. There was a significant difference in coronary calcium between men and women in all age groups; however, receiver-operating characteristic curves indicated that the test can be performed with equal accuracy in all of these subgroups.

CONCLUSIONS

Calcium screening with EBCT is a highly sensitive and moderately specific test to predict stenotic disease. Exclusion of coronary calcium defines a substantial subgroup of patients, albeit symptomatic, with a very low probability of significant stenoses.

Nifedipine in hypertensive emergencies

The effects and safety of using oral nifedipine 10-20 mg as acute antihypertensive treatment were studied in a single-blind placebo-controlled study of 25 consecutive patients with very high blood pressure requiring emergency reduction. In addition the effect of this treatment on cerebral blood flow was investigated using xenon-133 in 10 patients randomly allocated to receive oral nifedipine or intravenous clonidine. Whereas placebo did not alter the blood pressure, oral nifedipine significantly reduced the systolic and diastolic blood pressures in all 25 patients (from 221 +/- 22/126 +/- 14 mm Hg to 152 +/- 20/89 +/- 12 mm Hg after 30 minutes, p less than 0.001). Heart rate increased from 74 +/- 11 to 84 +/- 11 beats/minute (p less than 0.01); this effect was inversely related to age (r = -0.65, p less than 0.01). The falls in systolic and diastolic blood pressures were closely related to the blood pressures before treatment ) r = 0.67, p less than 0.001 for systolic, and r = -0.58, p less than 0.01 for diastolic values). No serious unwanted effects were observed. Measurement of cerebral blood flow after nifedipine showed an increase in flow in four out of five patients. Clonidine, by contrast, reduced cerebral blood flow in all patients by up to 28%. Nifedipine is a simple, effective, and safe alternative drug for managing hypertensive emergencies, especially when continuous monitoring of the patient cannot be guaranteed.

16 degrees C rapid temperature variation in central greenland 70,000 years Ago

Variations in the (29)N(2)/(28)N(2) ratio of air bubbles trapped in polar ice cores and their relation to variations of the (18)O/(16)O of the ice allow past surface temperature variations and ice age-gas age differences to be determined. High-resolution measurements of (29)N(2)/(28)N(2) in Dansgaard-Oeschger event 19 (around 70,000 years before the present) in ice from Central Greenland show that at the beginning of the event, the ice age-gas age difference was 1090 +/- 100 years. With the use of a combined firn densification, temperature, and gas diffusion model, the delta(18)O(ice)-temperature coefficient alpha was determined to be 0. 42 +/- 0.05 per mil per kelvin. This coefficient implies a mean surface temperature change of 16.0 kelvin (between 14.3 and 18.1 kelvin), which differs substantially from values derived from borehole temperatures and modern spatial delta(18)O(ice)-surface temperature correlations.

Neurologic manifestations of cerebral air embolism as a complication of central venous catheterization

OBJECTIVE, PATIENTS, AND METHODS: A severe case of cerebral air embolism after unintentional central venous catheter disconnection was the impetus for a systematic literature review (1975-1998) of the clinical features of 26 patients (including our patient) with cerebral air embolism resulting from central venous catheter complications.

RESULTS

The jugular vein had been punctured in eight patients and the subclavian vein, in 12 patients. Embolism occurred in four patients during insertion, in 14 patients during unintentional disconnection, and in eight patients after removal and other procedures. The total mortality rate was 23%. Two types of neurologic manifestations may be distinguished: group A (n = 14) presented with encephalopathic features leading to a high mortality rate (36%); and group B (n = 12) presented with focal cerebral lesions resulting in hemiparesis or hemianopia affecting mostly the right hemisphere, with a mortality rate as high as 8%. In 75% of patients, an early computed tomography indicated air bubbles, proving cerebral air embolism. Hyperbaric oxygen therapy was performed in only three patients (12%). A cardiac defect, such as a patent foramen ovale was considered the route of right to left shunting in 6 of 15 patients (40%). More often, a pulmonary shunt was assumed (9 of 15 patients; 60%). For the remainder, data were not available.

CONCLUSION

When caring for critically ill patients needing central venous catheterization, nursing staff and physicians should be aware of this potentially lethal complication.

Overexpression of a cytosolic hydroxymethylglutaryl-CoA reductase leads to squalene accumulation in yeast

The enzyme 3-hydroxy-3-methylglutaryl-co-enzyme-A (HMG-CoA) reductase is known as the rate limiting enzyme in early sterol biosynthesis in eukaryotic cells. To eliminate this regulation in the yeast Saccharomyces cerevisiae, a truncated HMG1 gene, producing a form of the enzyme that lacks the membrane-binding region (i.e. amino acids 1-552), was constructed and overexpressed in this yeast. The transformed strains accumulated large amounts of the sterol precursor squalene, while the levels of ergosterol and a number of other sterol compounds were only slightly elevated. These findings suggest that HMG-CoA reductase is not the only rate-limiting step in sterol synthesis and its overexpression cannot significantly influence this pathway beyond the sterol precursor squalene.

Visualization of neuropeptide expression, transport, and exocytosis in Drosophila melanogaster

Neuropeptides affect an extremely diverse set of physiological processes. Neuropeptides are often coreleased with neurotransmitters but, unlike neurotransmitters, the neuropeptide target cells may be distant from the site(s) of secretion. Thus, it is often difficult to measure the amount of neuropeptide release in vivo by electrophysiological methods. Here we establish an in vivo system for studying the developmental expression, processing, transport, and release of neuropeptides. A GFP-tagged atrial natriuretic factor fusion (preproANF-EMD) was expressed in the Drosophila nervous system with the panneural promoter, elav. During embryonic development, proANF-EMD was first seen to accumulate in synaptic regions of the CNS in stage 17 embryos. By the third instar larval stage, highly fluorescent neurons were evident throughout the CNS. In the adult, fluorescence was pronounced in the mushroom bodies, antennal lobe, and the central complex. At the larval neuromuscular junction, proANF-EMD was concentrated in nerve terminals. We compared the release of proANF-EMD from synaptic boutons of NMJ 6/7, which contain almost exclusively glutamate-containing clear vesicles, to those of NMJ 12, which include the peptidergic type III boutons. Upon depolarization, approximately 60% of the tagged neuropeptide was released from NMJs of both muscles in 15 min, as assayed by decreased fluorescence. Although the elav promoter was equally active in the motor neurons that innervate both NMJs 6/7 and 12, NMJ 12 contained 46-fold more neuropeptide and released much more proANF-EMD during stimulation than did NMJ 6/7. Our results suggest that peptidergic neurons have an enhanced ability to accumulate and/or release neuropeptides as compared to neurons that primarily release classical neurotransmitters.

Formation of a carcinogenic aromatic amine from an azo dye by human skin bacteria in vitro

Azo dyes represent the major class of dyestuffs. They are metabolised to the corresponding amines by liver enzymes and the intestinal microflora following incorporation by both experimental animals and humans. For safety evaluation of the dermal exposure of consumers to azo dyes from wearing coloured textiles, a possible cleavage of azo dyes by the skin microflora should be considered since, in contrast to many dyes, aromatic amines are easily absorbed by the skin. A method for measuring the ability of human skin flora to reduce azo dyes was established. In a standard experiment, 3x10(11) cells of a culture of Staphylococcus aureus were incubated in synthetic sweat (pH 6.8, final volume 20 mL) at 28 degrees C for 24 h with Direct Blue 14 (C.I. 23850, DB 14). The reaction products were extracted and analysed using HPLC. The reduction product o-tolidine (3,3'-dimethylbenzidine, OT) could indeed be detected showing that the strain used was able to metabolise DB 14 to the corresponding aromatic amine. In addition to OT, two further metabolites of DB 14 were detected. Using mass spectrometry they were identified as 3,3'-dimethyl-4-amino-4'-hydroxybiphenyl and 3, 3'-dimethyl-4-aminobiphenyl. The ability to cleave azo dyes seems to be widely distributed among human skin bacteria, as, under these in vitro conditions, bacteria isolated from healthy human skin and human skin bacteria from strain collections also exhibited azo reductase activity. Further studies are in progress in order to include additional azo dyes and coloured textiles. At the moment, the meaning of the results with regard to consumer health cannot be finally assessed.

Distribution of bacteria in the epidermal layers and hair follicles of the human skin

Previous studies over recent years have revealed the presence of a resident bacterial population in the human skin throughout the entire body. However, the localization and composition of the bacteria within the epidermis and the skin appendages have not been fully investigated. Using differential tape stripping, cyanoacrylate skin surface biopsies and mapping of hair follicles, bacteria on the forearms of study participants were isolated, mapped, cultured and identified with respect to their origin within the epidermis and the hair follicles. Our studies showed that 85% of the bacteria were found within the first 6 corneocyte layers and roughly 25% of the cutaneous bacterial population were localized within the hair follicles. The microbial flora of the skin between individuals is subject to considerable fluctuations. Micrococcaceae represent the biggest fraction of hair-follicle-associated bacteria. The techniques developed for this study allowed us to selectively investigate the bacterial population within the hair follicles. Our results point out the role of skin appendages as potential microbial reservoirs and the need to develop new antiseptic formulations that sufficiently penetrate into the hair follicles.

The design, physical properties and clinical utility of an iris collimator for robotic radiosurgery

Robotic radiosurgery using more than one circular collimator can improve treatment plan quality and reduce total monitor units (MU). The rationale for an iris collimator that allows the field size to be varied during treatment delivery is to enable the benefits of multiple-field-size treatments to be realized with no increase in treatment time due to collimator exchange or multiple traversals of the robotic manipulator by allowing each beam to be delivered with any desired field size during a single traversal. This paper describes the Iris variable aperture collimator (Accuray Incorporated, Sunnyvale, CA, USA), which incorporates 12 tungsten-copper alloy segments in two banks of six. The banks are rotated by 30 degrees with respect to each other, which limits the radiation leakage between the collimator segments and produces a 12-sided polygonal treatment beam. The beam is approximately circular, with a root-mean-square (rms) deviation in the 50% dose radius of <0.8% (corresponding to <0.25 mm at the 60 mm field size) and an rms variation in the 20-80% penumbra width of about 0.1 mm at the 5 mm field size increasing to about 0.5 mm at 60 mm. The maximum measured collimator leakage dose rate was 0.07%. A commissioning method is described by which the average dose profile can be obtained from four profile measurements at each depth based on the periodicity of the isodose line variations with azimuthal angle. The penumbra of averaged profiles increased with field size and was typically 0.2-0.6 mm larger than that of an equivalent fixed circular collimator. The aperture reproducibility is < or =0.1 mm at the lower bank, diverging to < or =0.2 mm at a nominal treatment distance of 800 mm from the beam focus. Output factors (OFs) and tissue-phantom-ratio data are identical to those used for fixed collimators, except the OFs for the two smallest field sizes (5 and 7.5 mm) are considerably lower for the Iris Collimator. If average collimator profiles are used, the assumption of circular symmetry results in dose calculation errors that are <1 mm or <1% for single beams across the full range of field sizes; errors for multiple non-coplanar beam treatment plans are expected to be smaller. Treatment plans were generated for 19 cases using the Iris Collimator (12 field sizes) and also using one and three fixed collimators. The results of the treatment planning study demonstrate that the use of multiple field sizes achieves multiple plan quality improvements, including reduction of total MU, increase of target volume coverage and improvements in conformality and homogeneity compared with using a single field size for a large proportion of the cases studied. The Iris Collimator offers the potential to greatly increase the clinical application of multiple field sizes for robotic radiosurgery.

Chemosensory event-related potentials in response to trigeminal and olfactory stimulation in idiopathic Parkinson's disease

Decrease of olfactory function in patients with Parkinson's disease (PD) has been reported by several authors. The current study investigated olfaction in PD patients using olfactory event-related potentials (OERPs) as an electrophysiologic correlate of olfactory function in combination with psychophysical testing. A specific focus was the influence of antiparkinsonian drugs. We investigated PD patients treated with antiparkinsonian drugs (n = 13) and PD patients who received no pharmacologic treatment (n = 18). They were compared to age- and sex-matched control subjects (n = 38). To obtain OERPs, stimulants were chosen to stimulate specifically the olfactory nerve (2.1 ppm vanillin, 0.8 ppm H2S). In addition, chemosomatosensory event-related potentials were recorded after trigeminal stimulation with 52% v/v CO2. Moreover, the subjects' ability to identify and to discriminate odorants was tested by means of a "squeeze bottle" technique. The study yielded the following major results: (1) Odor identification was impaired in PD patients. It was not influenced by treatment with antiparkinsonian drugs. (2) The OERP latencies were prolonged in both PD patients taking and not taking antiparkinsonian drugs; however, this effect was more pronounced in PD patients taking antiparkinsonian drugs. (3) The intranasal chemosensory trigeminal system seemingly was neither affected by the neuronal degeneration seen in PD nor by treatment with antiparkinsonian drugs.

Perspectives in the biological function and the technological application of polygalacturonases

Polygalacturonases (PG) have evolved in the past years from a pectinase "simply" being used for food processing to an important parameter in plant-fungal interaction. PG-inhibiting proteins (PGIP) that are synthesised in plants as a specific response to PGs of pathogenic fungi, have become a focus as a possible target in resistance breeding, and PGIPs are also a concern as an inhibiting factor in food processing. Plant PGs have been identified as a major factor in fruit ripening, and PG-deficient transgenic plants have been bred. Mainly fungal PGs are used in industrial processes for juice clarification and the range of enzymes is being extended through new recombinant and non-recombinant fungal strains. Finally, novel fields of application can be envisaged for PGs in the production of oligogalacturonides as functional food components. Here we aim to highlight the various fields where PGs are encountered and where they are of biological or technological importance.

Radiologic and endoscopic evaluation for laparoscopic adjustable gastric banding: preoperative and follow-up

BACKGROUND

Laparoscopic adjustable silicone gastric banding (LASGB) has replaced vertical banded gastroplasty (VBG) as the most widespread restrictive bariatric operation in Europe. Although these two procedures are similar in principle, the experience concerning the preoperative examinations and follow-up cannot be arbitrarily transferred from VBG to LASGB. The reasons for and consequences drawn from radiologic and endoscopic examinations are described.

METHODS

From December 1996 to January 2000, 148 patients (84% women, average age 39 years, body weight 127 kg, BMI 45 kg/m2) underwent LASGB. The mean follow-up was 17 months. Upper GI series, abdominal ultrasound, and gastroscopy were done before operation. The postoperative stoma adjustments were performed under radiological observation. All adjustments were analyzed.

RESULTS

Preoperative: Of 147 upper GI series, 74 showed hiatal hernia, 2 motility disorders, and 1 an incomplete malrotation. In 104 gastroscopies, 35 reflux and 53 gastritis with 24 Helicobacter pylori infections were found. Postoperative: On average, 2.7 radiological adjustments were done per patient. Until satisfactory satiety and weight reduction, 78% of the patients needed 0-3 adjustments. Besides routine adjustments, an additional 57 upper GI series were done in 35 patients, 44 times with opening of the stoma-diameter. A total of 14 slippages and 4 pouch enlargements were found. A gastroscopy was required in 12 patients.

CONCLUSION

Radiologic and endoscopic examinations before LASGB revealed pathology needing therapy in 42% of the patients and provided important additional information influencing the operative procedure. At an average follow-up of 17 months, 24% of the 148 patients needed unplanned additional upper GI series.

Eukaryotic expression: developments for structural proteomics

The production of sufficient quantities of protein is an essential prelude to a structure determination, but for many viral and human proteins this cannot be achieved using prokaryotic expression systems. Groups in the Structural Proteomics In Europe (SPINE) consortium have developed and implemented high‐throughput (HTP) methodologies for cloning, expression screening and protein production in eukaryotic systems. Studies focused on three systems: yeast (Pichia pastoris and Saccharomyces cerevisiae), baculovirus‐infected insect cells and transient expression in mammalian cells. Suitable vectors for HTP cloning are described and results from their use in expression screening and protein‐production pipelines are reported. Strategies for co‐expression, selenomethionine labelling (in all three eukaryotic systems) and control of glycosylation (for secreted proteins in mammalian cells) are assessed.

Transmission of Creutzfeldt-Jakob disease via a corneal transplant

A 45 year old woman is reported who initially presented with a cerebellar syndrome, severe ataxia, and dysarthria. She rapidly deteriorated to coma vigile with bilateral myoclonic jerks, flexion rigidity, and immobility necessitating complete nursing. Her EEG showed generalised slow activity and periodic biphasic and triphasic waves. The CSF concentration of neuron specific enolase was very high. Consequently the diagnosis of Creutzfeldt-Jakob disease was established. Eight months later she died of respiratory complications. Thirty years earlier the patient had undergone corneal transplantation for keratoconus. Review of the organ donor's hospital records showed that death was caused by intercurrent pneumonia subsequent to subacute spongiform encephalopathy confirmed by necropsy. In view of two previous case reports in the literature it is presumed that the cadaveric cornea was the source of transmission of Creutzfeldt-Jakob disease in this patient.

Different TBP-associated factors are required for mediating the stimulation of transcription in vitro by the acidic transactivator GAL-VP16 and the two nonacidic activation functions of the estrogen receptor

The estrogen receptor (ER) contains two nonacidic transcriptional activation functions, AF-1 and AF-2 (formerly TAF-1 and TAF-2). In this study we show that AF-1 and AF-2 are able to stimulate transcription in vitro in a HeLa cell system when fused to the DNA binding domain of the yeast activator GAL4. We also demonstrate that a factor(s) required for the function of the ER AFs is chromatographically separable from a factor(s) necessary for the activity of the acidic activation domain of VP16. Moreover, immunoprecipitation experiments using a monoclonal antibody directed against the TATA box binding protein (TBP) indicate, that these different factors are associated with TBP in distinct TFIID complexes.

Creutzfeldt-Jakob disease via dural and corneal transplants

A review of all published cases of iatrogenic Creutzfeldt-Jakob disease (CJD) via dural (N=71) and corneal (N=4) transplants is given. All but three of the dural cases were obviously due to a commercial product recalled in 1996. Two of the corneal grafts were taken from patients who had died of sporadic CJD. These cases differed from CJD due to human growth hormone injections and the new variant. Instead. they were akin to sporadic cases, but memory loss, disorders of higher cerebral functions and extrapyramidal signs were fewer, while cerebellar abnormalities were more frequent. Progressive dysarthria and gait disorder/gait ataxia were prominent signs during the early stages, myocloni the most salient feature later. A nonperiodic EEG did not contradict the diagnosis. Using current diagnostic criteria the disease was underdiagnosed ante mortem. Utmost care is needed in selecting, harvesting and handling dural and corneal grafts to avoid inadvertent transmission of CJD.

A quantitative immunohistochemical study on the time-dependent course of acute inflammatory cellular response to human brain injury

The time-dependent inflammatory cell reaction in human cortical contusions has been investigated during the first 30 weeks after blunt head injury. Immunohistochemical staining was carried out using CD 15 for granulocytes and LCA, CD 3 and UCHL-1 for mononuclear leucocytes. In order to provide reliable data for a forensic wound age estimation, the intensity of the cellular reaction was evaluated with a quantitative image analysis system. CD 15-labelled granulocytes were detectable earliest 10 min after brain injury, whereas significantly increased numbers of mononuclear leucocytes occurred in cortical contusions after a postinfliction interval of at least 1.1 days (LCA), 2 days (CD 3) or 3.7 days (UCHL-1), respectively.

Deterministic quantum teleportation with feed-forward in a solid state system

Engineered macroscopic quantum systems based on superconducting electronic circuits are attractive for experimentally exploring diverse questions in quantum information science. At the current state of the art, quantum bits (qubits) are fabricated, initialized, controlled, read out and coupled to each other in simple circuits. This enables the realization of basic logic gates, the creation of complex entangled states and the demonstration of algorithms or error correction. Using different variants of low-noise parametric amplifiers, dispersive quantum non-demolition single-shot readout of single-qubit states with high fidelity has enabled continuous and discrete feedback control of single qubits. Here we realize full deterministic quantum teleportation with feed-forward in a chip-based superconducting circuit architecture. We use a set of two parametric amplifiers for both joint two-qubit and individual qubit single-shot readout, combined with flexible real-time digital electronics. Our device uses a crossed quantum bus technology that allows us to create complex networks with arbitrary connecting topology in a planar architecture. The deterministic teleportation process succeeds with order unit probability for any input state, as we prepare maximally entangled two-qubit states as a resource and distinguish all Bell states in a single two-qubit measurement with high efficiency and high fidelity. We teleport quantum states between two macroscopic systems separated by 6 mm at a rate of 10(4) s(-1), exceeding other reported implementations. The low transmission loss of superconducting waveguides is likely to enable the range of this and other schemes to be extended to significantly larger distances, enabling tests of non-locality and the realization of elements for quantum communication at microwave frequencies. The demonstrated feed-forward may also find application in error correction schemes.

The novel adaptor protein Swiprosin-1 enhances BCR signals and contributes to BCR-induced apoptosis

B-cell receptor (BCR) signals are essential for B-cell differentiation, homeostasis and negative selection, which are regulated by the strength and quality of BCR signals. Recently, we identified a new adaptor protein, Swiprosin-1, in lipid rafts of B-cell lines that undergo apoptosis after BCR stimulation. During murine B-cell development, Swiprosin-1 exhibited highest expression in immature B cells of the bone marrow, but was also expressed in resting and activated splenic B cells and in non-lymphoid tissue, especially in the brain. Ectopic expression of Swiprosin-1 in the immature murine B-cell line WEHI231 enhanced spontaneous and BCR-induced apoptosis. In contrast, short hairpin RNA (shRNA)-mediated downregulation of Swiprosin-1 impaired specifically spontaneous and BCR-elicited apoptosis, but not BCR-induced G1 cell cycle arrest and upregulation of the cell cycle inhibitor p27(Kip1). In accordance, Swiprosin-1 abundance regulated net cell growth of WEHI231 cell populations through reciprocal regulation of Bcl-xL, but not Bim, thereby controlling spontaneous apoptosis. Swiprosin-1-enhanced apoptosis was blocked through nuclear factor kappaB-activating stimuli, namely B-cell-activating factor of the TNF family, anti-CD40 and lipopolysaccharide (LPS). This correlated with enhanced BCR-induced IkappaB-alpha phosphorylation and degradation in cells expressing a Swiprosin-1-specific shRNA. Finally, ectopic Swiprosin-1 expression enhanced BCR-induced cell death in primary, LPS-stimulated splenic B cells. Hence, Swiprosin-1 may regulate lifespan and BCR signaling thresholds in immature B cells.

Specific Lactobacillus/Mutans Streptococcus co-aggregation

Selective interaction of mutans streptococci with benign bacteria could present an opportunity for their removal from the mouth without disruption of other oral flora. This study was conducted to find probiotic lactobacilli that could specifically co-aggregate in vitro with mutans streptococci, but not with other plaque commensals. A search of 624 lactobacilli among a large culture library revealed 6 strains, all classifiable as L. paracasei or L. rhamnosus, which met this criterion. Such novel, specific co-aggregation, however, was not a general characteristic of these species or the genus Lactobacillus. The co-aggregation by these specific lactobacilli was characterized as heat treatment (autoclaving)- and protease-resistant, lectin-independent, not inactivated by sugar substitutes, operational over a wide pH range, unaffected by whole saliva, but calcium-dependent. It is thus seen to present a potential strategy for in vivo alteration of plaque biofilm and caries.

Observation of two-mode squeezing in the microwave frequency domain

Continuous variable entanglement between two modes of a radiation field is usually studied at optical frequencies. Here we demonstrate experiments that show the entanglement between microwave photons of different energy in a broadband squeezed beam. We use a Josephson parametric amplifier to generate the two-mode correlated state and detect all four quadrature components simultaneously in a two-channel heterodyne setup using amplitude detectors. Analyzing two-dimensional phase space histograms for all possible pairs of quadratures allows us to determine the full covariance matrix, which is in good agreement with the one expected for a two-mode squeezed state.

The interaction of human papillary and reticular fibroblasts and human keratinocytes in the contraction of three-dimensional floating collagen lattices

Fibroblasts derived from the papillary and reticular dermis of human skin and human keratinocytes show differences in their abilities to contract floating three-dimensional gels constructed from type I collagen. Reticular fibroblasts produce greater gel contraction than papillary fibroblasts. When equal numbers of papillary and reticular fibroblasts are mixed in the gels, papillary fibroblasts consistently inhibit gel contraction by reticular fibroblasts indicating interaction between these cell types in the contraction process. Surprisingly, keratinocytes alone produce greater gel contraction than that produced by either fibroblast type. Cooperativity in the gel contraction process is observed when fibroblasts are incorporated into the collagen matrix and keratinocytes are seeded onto the gel surface. Keratinocytes and dermal fibroblasts adhere to the collagen fibril to induce gel contraction by different mechanisms. Fibroblast contraction of collagen gels does not require fibronectin but is a serum-dependent reaction. In contrast, keratinocyte contraction of collagen gels occurs in a serum-free environment. Polyclonal, affinity-purified antibodies to human plasma fibronectin at high concentrations do not inhibit gel contraction by keratinocytes, making unlikely the possibility that fibronectin synthesized by the keratinocyte is a significant factor in the gel contraction process. We are currently examining the possibilities either that keratinocytes are synthesizing other adhesion proteins or that receptors on the cell surface can interact directly with the collagen fiber.

Rapid transbilayer movement of fluorescent phospholipid analogues in the plasma membrane of endocytosis-deficient yeast cells does not require the Drs2 protein

Evidence is presented that endocytosis-deficient Saccharomyces cerevisiae end4 yeast cells rapidly internalize the fluorescent phospholipid analogues 1-palmitoyl-2-{6-[7-nitro-2,1, 3-benzoxadiazol-4-yl(NBD)amino] caproyl}phosphatidylcholine (P-C6-NBD-PtdCho) and P-C6-NBD-phosphatidylserine (P-C6-NBD-PtdSer). Both analogues redistributed between the exoplasmic and cytoplasmic leaflet with a half-time of < 15 min at 0 degrees C. The plateau of internalized analogues was about 70%. Transbilayer movement is probably protein-mediated, as the flip-flop of both analogues was very slow in liposomes composed of plasma-membrane lipids. Rapid analogue internalization was not abolished on depletion of intracellular ATP by about 90%. For P-C6-NBD-PtdCho only was a moderate decrease in the plateau of internalized analogues of about 20% observed, while that of P-C6-NBD-PtdSer was not affected. The Drs2 protein plays only a minor role, if any, in the rapid transbilayer movement of analogues in S. cerevisiae end4 cells. In S. cerevisiae end4 Deltadrs2 cells harbouring both an end4 allele and a drs2 null allele, about 60% and 50% of P-C6-NBD-PtdCho and P-C6-NBD-PtdSer, respectively, became internalized within 15 min at 0 degrees C. The preferential orientation of P-C6-NBD-PtdSer to the cytoplasmic leaflet is in qualitative agreement with the sequestering of endogenous phosphatidylserine to the cytoplasmic leaflet, as assessed by binding of annexin V. Virtually no binding of annexin V to spheroplasts of the parent wild-type strain or the mutant strains was observed. Likewise, no difference in the exposure of endogenous aminophospholipids to the exoplasmic leaflet between these strains was found by labelling with trinitrobenzenesulfonic acid. Thus, lipid asymmetry, at least of aminophospholipids, was preserved in S. cerevisiae end4 cells independently of the presence of the Drs2 protein.

[Olfactory testing with "sniffin' sticks" for clinical diagnosis of Parkinson disease]

Olfactory dysfunction seems to be one of the most frequent symptoms in idiopathic parkinsonian syndrome (IPS). In contrast to the increasing number of studies providing evidence of the usefulness of olfactory tests in the diagnosis of IPS, clinical assessment of olfactory function is rarely performed. This may be due to the lack of an easy-to-use, inexpensive, standardized, and reliable test. In this study, we administered the newly developed "sniffin' sticks" test to a group of 40 nondemented IPS patients and compared the results with 40 healthy controls matched for age, gender, and smoking habits. In all three subtests including odor identification, odor detection threshold, and odor discrimination, the control group scored significantly better than the IPS group, yielding a specificity and sensitivity of 90% each. Our results indicate that olfactory disturbances in IPS can be found at early stages of the disease, appear bilaterally, and do not correlate with the dominant side of parkinsonism. Therefore, we emphasize that olfactory testing may be a useful tool in the diagnosis of IPS.