The cuticle proteome of a planktonic crustacean

The cuticles of arthropods provide an interface between the organism and its environment. Thus, the cuticle's structure influences how the organism responds to and interacts with its surroundings. Here, we used label-free quantification proteomics to provide a proteome of the moulted cuticle of the aquatic crustacean Daphnia magna, which has long been a prominent subject of studies on ecology, evolution, and developmental biology. We detected a total of 278 high-confidence proteins. Using protein sequence domain and functional enrichment analyses, we identified chitin-binding structural proteins and chitin-modifying enzymes as the most abundant protein groups in the cuticle proteome. Structural cuticular protein families showed a similar distribution to those found in other arthropods and indicated proteins responsible for the soft and flexible structure of the Daphnia cuticle. Finally, cuticle protein genes were also clustered as tandem gene arrays in the D. magna genome. The cuticle proteome presented here will be a valuable resource to the Daphnia research community, informing genome annotations and investigations on diverse topics such as the genetic basis of interactions with predators and parasites.

The Disease Severity Index for Inflammatory Bowel Disease Is a Valid Instrument that Predicts Complicated Disease

BACKGROUND

The disease severity index (DSI) for inflammatory bowel disease (IBD) combines measures of disease phenotype, inflammatory activity, and patient-reported outcomes. We aimed to validate the DSI and assess its utility in predicting a complicated IBD course.

METHODS

A multicenter cohort of adults with IBD was recruited. Intraclass correlation coefficients (ICCs) and weighted Kappa assessed inter-rater reliability. Cronbach's alpha measured internal consistency of DSI items. Spearman's rank correlations compared the DSI with endoscopic indices, symptom indices, quality of life, and disability. A subgroup was followed for 24 months to assess for a complicated IBD course. Area under the receiver operating characteristics curve (AUROC) and multivariable logistic regression assessed the utility of the DSI in predicting disease progression.

RESULTS

Three hundred and sixty-nine participants were included (Crohn's disease [CD], n = 230; female, n = 194; mean age, 46 years [SD, 15]; median disease duration, 11 years [interquartile range, 5-21]), of which 171 (CD, n = 99; ulcerative colitis [UC], n = 72) were followed prospectively. The DSI showed inter-rater reliability for CD (ICC 0.93, n = 65) and UC (ICC 0.97, n = 33). The DSI items demonstrated inter-rater agreement (Kappa > 0.4) and internal consistency (CD, α > 0.59; UC, α > 0.75). The DSI was significantly associated with endoscopic activity (CDn=141, r = 0.65, P < .001; UCn=105, r = 0.80, P < .001), symptoms (CDn=159, r = 0.69, P < .001; UCn=132, r = 0.58, P < .001), quality of life (CDn=198, r = -0.59, P < .001; UCn=128, r = -0.68, P < .001), and disability (CDn=83, r = -0.67, P < .001; UCn=52, r = -0.74, P < .001). A DSI of 23 best predicted a complicated IBD course (AUROC = 0.82, P < .001) and was associated with this end point on multivariable analyses (aOR, 9.20; 95% confidence interval, 3.32-25.49).

CONCLUSIONS

The DSI reliably encapsulates factors contributing to disease severity and accurately prognosticates the longitudinal IBD course.

Balancing selection for pathogen resistance reveals an intercontinental signature of Red Queen coevolution

The link between long-term host–parasite coevolution and genetic diversity is key to understanding genetic epidemiology and the evolution of resistance. The model of Red Queen host–parasite coevolution posits that high genetic diversity is maintained when rare host resistance variants have a selective advantage, which is believed to be the mechanistic basis for the extraordinarily high levels of diversity at disease-related genes such as the major histocompatibility complex in jawed vertebrates and R-genes in plants. The parasites that drive long-term coevolution are, however, often elusive. Here we present evidence for long-term balancing selection at the phenotypic (variation in resistance) and genomic (resistance locus) level in a particular host–parasite system: the planktonic crustacean Daphnia magna and the bacterium Pasteuria ramosa. The host shows widespread polymorphisms for pathogen resistance regardless of geographic distance, even though there is a clear genome-wide pattern of isolation by distance at other sites. In the genomic region of a previously identified resistance supergene, we observed consistent molecular signals of balancing selection, including higher genetic diversity, older coalescence times, and lower differentiation between populations, which set this region apart from the rest of the genome. We propose that specific long-term coevolution by negative-frequency-dependent selection drives this elevated diversity at the host's resistance loci on an intercontinental scale and provide an example of a direct link between the host’s resistance to a virulent pathogen and the large-scale diversity of its underlying genes.

Microsporidia with Vertical Transmission Were Likely Shaped by Nonadaptive Processes

Microsporidia have the leanest genomes among eukaryotes, and their physiological and genomic simplicity has been attributed to their intracellular, obligate parasitic life-style. However, not all microsporidia genomes are small or lean, with the largest dwarfing the smallest ones by at least an order of magnitude. To better understand the evolutionary mechanisms behind this genomic diversification, we explore here two clades of microsporidia with distinct life histories, Ordospora and Hamiltosporidium, parasitizing the same host species, Daphnia magna. Based on seven newly assembled genomes, we show that mixed-mode transmission (the combination of horizontal and vertical transmission), which occurs in Hamiltosporidium, is found to be associated with larger and AT-biased genomes, more genes, and longer intergenic regions, as compared with the exclusively horizontally transmitted Ordospora. Furthermore, the Hamiltosporidium genome assemblies contain a variety of repetitive elements and long segmental duplications. We show that there is an excess of nonsynonymous substitutions in the microsporidia with mixed-mode transmission, which cannot be solely attributed to the lack of recombination, suggesting that bursts of genome size in these microsporidia result primarily from genetic drift. Overall, these findings suggest that the switch from a horizontal-only to a mixed mode of transmission likely produces population bottlenecks in Hamiltosporidium species, therefore reducing the effectiveness of natural selection, and allowing their genomic features to be largely shaped by nonadaptive processes.

Impact of intended and relative dose intensity of R-CHOP in a large, consecutive cohort of elderly diffuse large B-cell lymphoma patients treated with curative intent: no difference in cumulative incidence of relapse comparing patients by age

BACKGROUND

The increasing incidence of diffuse large B-cell lymphoma (DLBCL) in ageing populations places a significant burden on healthcare systems. Co-morbidity, frailty, and reduced organ and physiological reserve contribute to treatment-related complications. The optimal dose intensity of R-CHOP to optimize outcome across different ages with variable frailty and comorbidity burden is unclear.

OBJECTIVES AND METHODS

We examined the influence of intended (IDI) and relative (RDI) dose intensity of the combination of cyclophosphamide and doxorubicin, age and comorbidity on outcomes for DLBCL patients ≥70 years in a representative, consecutive cohort across eight UK centres (2009-2018). We determined predictors of survival using multivariable Cox regression, and predictors of recurrence before death using competing risks regression.

RESULTS

Porgression-free survival (PFS) and overall survival (OS) were significantly inferior in patients ≥80 vs. 70-79 years (P < 0.001). In contrast, 2-year cumulative relapse incidence, when accounting for non-relapse mortality as a competing risk, was no different between 70-79 vs. ≥80 years (P = 0.27) or comorbidity status (CIRS-G: 0-6 vs. >6) (P = 0.27). In 70-79 years, patients with an IDI ≥80% had a significantly improved PFS and OS (P < 0.001) compared to IDI < 80%. Conversely, in patients ≥80 years, there was no difference in PFS (P = 0.88) or OS (P = 0.75) according to IDI <80% vs. ≥80%. On multivariable analysis, when comparing by age, there was a significantly higher cumulative relapse rate for patients aged 70-79 years with an IDI <80% (vs. >80%) (P = 0.04) but not for patients ≥80 years comparing IDI (P = 0.32).

CONCLUSION

'R-mini-CHOP' provides adequate lymphoma-specific disease control and represents a reasonable treatment option in elderly patients ≥80 years aiming for cure.

ESMO Consensus Conference on malignant lymphoma: general perspectives and recommendations for the clinical management of the elderly patient with malignant lymphoma

The European Society for Medical Oncology (ESMO) consensus conference on mature B cell lymphomas and chronic lymphocytic leukaemia (CLL) was held on 20 June 2015 in Lugano, Switzerland, and included a multidisciplinary panel of 25 leading experts. The aim of the conference was to develop recommendations on critical subjects difficult to consider in detail in the ESMO Clinical Practice Guidelines. The following areas were identified: (1) the elderly patient, (2) prognostic factors suitable for clinical use, and (3) the 'ultra-high-risk' group. Before the conference, the expert panel was divided into three working groups; each group focused on one of these areas in order to address clinically-relevant questions relating to that topic. All relevant scientific literature, as identified by the experts, was reviewed in advance. During the consensus conference, each working group developed recommendations to address each of the four questions assigned to their group. These recommendations were presented to the entire panel and a consensus was reached. This consensus, which was further developed in continuous post-meeting discussions, formed the basis of three manuscripts, each covering one of the three key areas identified. This manuscript presents the consensus recommendations regarding the clinical management of elderly patients diagnosed with malignant lymphoma. Four clinically-relevant topics identified by the panel were: 1) how to define patient fitness, 2) assessing quality of life, 3) diagnostic work-up and 4) clinical management of elderly patients with lymphoma. Each of these key topics is addressed in the context of five different lymphoma entities, namely: CLL, follicular lymphoma, mantle cell lymphoma, peripheral T-cell lymphoma and diffuse large B-cell lymphoma. Results, including a summary of evidence supporting each recommendation, are detailed in this manuscript.

Identification of General Patterns of Sex-Biased Expression in Daphnia, a Genus with Environmental Sex Determination

Daphnia reproduce by cyclic-parthenogenesis, where phases of asexual reproduction are intermitted by sexual production of diapause stages. This life cycle, together with environmental sex determination, allow the comparison of gene expression between genetically identical males and females. We investigated gene expression differences between males and females in four genotypes of Daphnia magna and compared the results with published data on sex-biased gene expression in two other Daphnia species, each representing one of the major phylogenetic clades within the genus. We found that 42% of all annotated genes showed sex-biased expression in D. magna This proportion is similar both to estimates from other Daphnia species as well as from species with genetic sex determination, suggesting that sex-biased expression is not reduced under environmental sex determination. Among 7453 single copy, one-to-one orthologs in the three Daphnia species, 707 consistently showed sex-biased expression and 675 were biased in the same direction in all three species. Hence these genes represent a core-set of genes with consistent sex-differential expression in the genus. A functional analysis identified that several of them are involved in known sex determination pathways. Moreover, 75% were overexpressed in females rather than males, a pattern that appears to be a general feature of sex-biased gene expression in Daphnia.

Genomic evidence for population-specific responses to co-evolving parasites in a New Zealand freshwater snail

Reciprocal co-evolving interactions between hosts and parasites are a primary source of strong selection that can promote rapid and often population- or genotype-specific evolutionary change. These host-parasite interactions are also a major source of disease. Despite their importance, very little is known about the genomic basis of co-evolving host-parasite interactions in natural populations, especially in animals. Here, we use gene expression and sequence evolution approaches to take critical steps towards characterizing the genomic basis of interactions between the freshwater snail Potamopyrgus antipodarum and its co-evolving sterilizing trematode parasite, Microphallus sp., a textbook example of natural coevolution. We found that Microphallus-infected P. antipodarum exhibit systematic downregulation of genes relative to uninfected P. antipodarum. The specific genes involved in parasite response differ markedly across lakes, consistent with a scenario where population-level co-evolution is leading to population-specific host-parasite interactions and evolutionary trajectories. We also used an F_ST -based approach to identify a set of loci that represent promising candidates for targets of parasite-mediated selection across lakes as well as within each lake population. These results constitute the first genomic evidence for population-specific responses to co-evolving infection in the P. antipodarum-Microphallus interaction and provide new insights into the genomic basis of co-evolutionary interactions in nature.

A comprehensive geriatric assessment screening questionnaire (CGA-GOLD) for older people undergoing treatment for cancer

Oncology services do not routinely assess broader needs of older people with cancer. This study evaluates a comprehensive geriatric assessment and comorbidity screening questionnaire (CGA-GOLD) covering evidence-based domains and quality of life (EORTC-QLQ-C30). Patients aged 65+ attending oncology services were recruited into (1) Observational cohort (completed CGA-GOLD, received standard oncology care), (2) Intervention cohort (responses categorised 'low-risk', 'high-risk', 'possible need' by geriatricians). N = 417 observational patients (1002 invited by post, 418 consented, age 73.9 ± 5.4) completed CGA-GOLD in 11.7 ± 7.9 min, 86.3% required no assistance, 3.1% overall missing responses. Multiple problems reported: hypertension (18.1%), diabetes (16.9%), dyspnoea on flat surfaces (27.6%), polypharmacy (46%), difficulty walking (14.9%), fatigue (40.5%), living alone (30.9%), social isolation (11.2%), recent functional dependence (27.8%), urinary incontinence (21.4%), falls (13.3%). 237/239 intervention patients completed CGA-GOLD and consecutive subsets examined. The doctor and nurse specialist independently identified same need level in 87.3% (high inter-rater reliability kappa = 0.80), taking 1-2 min per questionnaire. Need level remained unchanged following hospital notes review against responses in 90% (75/83). 'Possible need' patients were telephoned with change in 29% (16/55) to low-risk and none to high-risk, confirming high need was not being missed. CGA-GOLD screening questionnaire was acceptable to older patients, feasibly administered in NHS cancer services, described comorbidities, CGA and QOL needs, and reliably identified higher risk patients requiring further input for optimal cancer treatment.

The impact of low-grade toxicity in older people with cancer undergoing chemotherapy

Background:

Significant toxicity in chemotherapy trials is usually defined as grade ⩾3. In clinical practice, however, multiple lower grade toxicities are often considered meaningful. The purpose of this observational cohort study was to identify which level of toxicity triggers treatment modification and early discontinuation of chemotherapy in older people.

Methods:

Patients aged 65+ were recruited in a central London hospital. A total of 108 patients were recruited at the start of new chemotherapy treatment between October 2010 and July 2012.

Results:

Mean age was 72.1±5 years, median 72 and range 65–86 years. Of the patients, 50.9% (55) were male with gastrointestinal (49), gynaecological (18), lung (15) and other cancers (26). Chemotherapy was palliative in 59.3% (64/108), curative/ neoadjuvant/adjuvant in the others. Mean number of cycles completed was 4.2±3. Treatment modifications due to toxicity occurred in 60 (55.6%) patients, 35% (21/60) of whom had no greater than grade 2 toxicity. Early treatment discontinuation because of toxicity occurred in 23 patients (21.3%), 39.1% (9/23) of whom had no greater than grade 2 toxicity.

Conclusions:

Many older patients did not complete treatment as planned. Treatment was modified/discontinued even for one or two low-grade toxicities. Further work is required to clarify whether low-grade toxicity has a greater clinical impact in older people, or whether clinicians have a lower threshold for modifying/discontinuing treatment in older people.

A high pressure cell for supercritical CO₂ on-line chemical reactions studied with X-ray techniques

A versatile high pressure X-ray sample cell has been developed for conducting in situ time-resolved X-ray scattering experiments in the pressure and temperature regime required (pressures up to 210 bars and temperatures up to 120 °C) for chemical reactions in supercritical fluids. The large exit opening angle of the cell allows simultaneous performance of SAXS-WAXS experiments. Diamond windows are used in order to benefit from the combination of maximum strength, minimal X-ray absorption and chemical inertia. The sample cell can also be utilised for X-ray spectroscopy experiments over a wide range of photon energies. Results of the online synthesis of a block copolymer, poly(methyl methacrylate-block-poly(benzyl methacrylate), by Reversible Addition-Fragmentation Chain Transfer (RAFT) in a supercritical CO2 dispersion polymerisation will be discussed. The contribution of the density fluctuations, as function of temperature, to the X-ray scattering signal has been quantified in order to allow appropriate background subtractions.

New phase equilibrium analyzer for determination of the vapor-liquid equilibrium of carbon dioxide and permanent gas mixtures for carbon capture and storage

A high-pressure, phase equilibrium analyzer incorporating a fiber-optic reflectometer is described. The analyzer has been designed for measuring the vapor-liquid equilibrium data of multi-component mixtures of carbon dioxide and permanent gases, providing a novel tool to acquire of a large number of phase equilibrium data for the development of the new carbon capture and storage technologies. We demonstrate that the analyzer is suitable for determining both the bubble- and dew-point lines at temperature from 253 K and pressure up to 25 MPa using pure CO2 and two binary mixtures of CO2 + N2 and CO2 + H2.

The protective effect of antioxidants to a phototoxin-sensitive insect herbivore,Manduca sexta

Photo-activated plant secondary compounds have been shown to be toxic to many organisms including insects. Insect defenses include behavioral mechanisms such as light avoidance, as well as specific biochemical defenses such as antioxidants and antioxidant enzymes. These antioxidant defenses eliminate or quench the deleterious singlet oxygen and free radicals formed by these phototoxins. In this paper we examined the role of dietary antioxidants in protecting the phototoxin-sensitive insect herbivoreManduca sexta. Elevated dietary levels of the lipid-soluble antioxidantsΒ-carotene and vitamin E resulted in a concentration-dependent reduction in the mortality associated with treatment ofM. sexta larvae with the phototoxic thiopheneα-terthienyl. Elevated levels of dietary ascorbic acid had no effect, whereas reduced levels greatly increased the toxicity ofα-terthienyl. Tissue levels of antioxidants were shown to increase substantially in larvae fed antioxidant-supplemented diets. The results suggest that the ability to absorb and utilize plant-derived antioxidants could be an important defense against photo-activated plant secondary compounds and may have allowed some insects to exploit phototoxic plants.

Regulation of T lymphocyte subsets

Patterns of cytokine secretion and functional differences distinguish T lymphocyte subsets. T lymphocyte subsets are also regulated differentially. Most established CD8+ lymphocyte clones secrete gamma-interferon (IFN-gamma) but not interleukin 2 (IL-2) or IL-4. Using murine T cells which express a transgenic, antigen-specific alpha/beta T cell receptor (TCR) specific for L(d) class I major histocompatibility complex antigen, we have found that CD8+ lymphocytes can be divided into functional subsets. Freshly isolated CD8+ T cells are not cytolytic, do not proliferate and do not proliferate and do not secrete cytokines. Stimulation of TCR alone does not induce cytokine secretion, but cells become responsive to exogenous IL-2 or IL-4. Stimulation of CD28 together with TCR induces secretion of IL-2 and IFN-gamma, and cells proliferate without exogenous cytokines. Proliferation is necessary for the development of cytolytic activity. If IL-4 is present during initial stimulation, IL-4 is secreted following restimulation. Upon stimulation, some IL-4-producing murine CD8+ T cell clones express CD40 ligand (CD40L), and they potentiate proliferation and immunoglobulin secretion by small resting B cells. Thus, the CD8+ T cell subsets T cytotoxic 1 (Tc1) and Tc2 are analogous to CD4+ T helper 1 (Th1) and Th2. IL-2 production by naive CD8+ cells requires co-stimulation. IL-4 production by CD8+ T cells requires the presence of IL-4 during initial stimulation. Some IL-4-producing CD8+ T cells express CD40L following TCR stimulation and provide help for B cells.

Phase I study of an immunomodulatory thalidomide analog, CC-4047, in relapsed or refractory multiple myeloma

PURPOSE

To assess the safety, efficacy, and immunomodulatory effects of CC-4047 (Actimid; Celgene, San Diego, CA) in patients with relapsed or refractory myeloma.

PATIENTS AND METHODS

Twenty-four relapsed or refractory patients were treated with a dose-escalating regimen of oral CC-4047. Clinical responses and adverse effects were identified, and peripheral T-cell subsets, serum cytokines, and proangiogenic factors were evaluated.

RESULTS

CC-4047 was tolerated with no serious nonhematologic adverse events. All patients were eligible for analysis. Toxicity criteria during the initial 4 weeks of study were used to define the maximum-tolerated dose (MTD). During this period, one patient withdrew with a deep vein thrombosis (DVT) probably caused by an undiagnosed primary melanoma with lymphadenopathy in the groin, one patient withdrew because of progressive disease (PD), and three patients discontinued with neutropenia. Nineteen of 24 patients continued on treatment beyond 4 weeks to PD or development of a serious adverse event. Three further patients developed a DVT at 4, 9, and 11 months. Treatment resulted in a greater than 25% reduction in paraprotein in 67% of patients, 13 patients (54%) experienced a greater than 50% reduction in paraprotein, and four (17%) of 24 patients entered complete remission. The MTD was 2 mg/d. All patients showed increased CD45RO expression on CD4(+) and CD8(+) cells, with a concomitant decrease in CD45RA(+) cells. CC-4047 treatment was associated with significantly increased serum interleukin (IL)-2 receptor and IL-12 levels, which is consistent with activation of T cells and monocytes and macrophages.

CONCLUSION

This study demonstrates the safety and efficacy of CC-4047. The MTD of CC-4047 orally was 2 mg/d. This is the first report demonstrating in vivo T-cell costimulation by this class of compound, supporting a potential role for CC-4047 as an immunostimulatory adjuvant treatment.

Regulation of PKC delta expression by estrogen and rat placental lactogen-1 in luteinized rat ovarian granulosa cells

Protein kinase C (PKC) delta is dramatically upregulated in the corpus luteum in the second half of pregnancy in the rat. To gain insight into the hormonal regulation of PKC delta expression, studies were undertaken to analyze the regulation of PKC delta expression in a luteinized rat granulosa cell model. PKC delta protein expression was evaluated in luteinized granulosa cells, isolated from human (h)CG-treated immature female rats 7 h after the injection of an ovulatory dose of hCG and cultured up to 12 days. Cytochrome P450 cholesterol side chain cleavage enzyme expression was observed throughout the culture period, and a majority of the cells expressed steroidogenic acute regulatory protein and responded to rat placental lactogen (rPL)-1 by exhibiting hypertrophy, consistent with maintenance of the luteal phenotype. Both PKC delta protein and mRNA expression increased 3.5-4-fold with time of culture, and PKC delta mRNA expression could be eliminated by treatment of cells with the PKC inhibitor GF109203X. E(2) caused a specific dose- and time-dependent increase in expression of PKC delta protein of twofold, whereas PKC delta mRNA was unaffected by E(2) over a 12-day culture period. Treatment of cells with 500 ng/ml rPL-1 for the final 4 days of a 12-day culture in the absence of E(2) had no effect on PKC delta protein or mRNA expression, while treatment with 500 or 3000 ng/ml rPL-1 in the presence of E(2) significantly enhanced both PKC delta protein and mRNA expression (up to threefold). These results show that two of the major regulators of luteal function in the second half of pregnancy in the rat, E(2) and rPL-1, cooperate to regulate PKC delta expression in luteinized granulosa cells.

Degradation of the upper pulvinus in modern and fossil leaves of Cercis (Fabaceae)

Identification of fossil leaf impressions as Cercis has been questioned based upon the presence or absence of a pulvinus at the base of the lamina (upper pulvinus). In the present study, leaves of Cercis canadensis were examined before and after abscission to explore the degradation processes that could occur prior to fossilization, and the North American record for fossil foliage of Cercis was revised accordingly. Results for C. canadensis indicate that: (1) the pulvinus consists largely of tissues with nonlignified cells (a wide cortex, a nonlignified fiber sheath, phloem, and pith) that degrade rapidly after leaf abscission, (2) the lignified xylem tissue that remains in the pulvinus after degradation is in brittle strands, (3) the pulvinus degrades at a faster rate than the lamina or the petiole, and (4) the degraded pulvinus cushion leaves a semicircular pattern on the lamina. From examination of fossils as well as extant species, we: (1) demonstrated that in fossils, the upper pulvinus can show a greater degree of degradation than the adjoining petiole or lamina tissue, suggesting the degradation of upper pulvinus tissue is similar in modern vs. fossil specimens, (2) defined numerous other laminar characters that can be used in conjunction with, or in the absence of, an upper pulvinus to confirm the presence of Cercis in the fossil record, and (3) showed from those criteria that the earliest known North American fossil leaf record for Cercis, from a specimen newly reported in the present study, is from the middle Miocene Succor Creek flora of Oregon.

Amino acid sequence differences cannot fully explain interspecific variation in thermal sensitivities of gobiid fish A4-lactate dehydrogenases (A4-LDHs)

We compared the deduced amino acid sequences, heat stabilities and thermal sensitivities of a kinetic property, the apparent Michaelis&shy;Menten constant (Km) of pyruvate, of A4-lactate dehydrogenase (A4-LDH) in four species of goby fishes (Family Gobiidae), adapted to different temperatures, to examine how changes in primary structure influence the adaptation of enzymes. The effect of temperature on Km of pyruvate reflected each species' environmental temperature. For the most eurythermal species, Gillichthys seta, which is endemic to shallow intertidal regions of the upper Gulf of California and encounters temperatures between approximately 9 and 40 &deg;C, Km of pyruvate was minimally affected by temperature, compared with the A4-LDH orthologues from a less eurythermal congener, G. mirabilis (9&shy;30 &deg;C), a cold temperate goby, Coryphopterus nicholsi (10&shy;18 &deg;C) and a tropical species, C. personatus (25&shy;32 &deg;C). Heat denaturation profiles failed to correlate with habitat temperature; G. mirabilis A4-LDH was most thermally stable, followed by the orthologues of C. nicholsi and G. seta. Complementary DNAs (cDNAs) encoding LDH-As of G. seta, Gulf of California and Pacific coast populations of G. mirabilis and C. nicholsi were isolated and sequenced, and the corresponding amino acid sequences deduced. The nucleotide sequences of LDH-A of the two populations of G. mirabilis were identical. Five nucleotide differences in the coding region and one amino acid substitution (at position 78) distinguished LDH-As of G. mirabilis and C. nicholsi. The substitution of a glycyl residue (C. nicholsi) for an alanyl residue (G. mirabilis) may account for the difference in thermal stability between these two orthologues. Comparisons of the LDH-A cDNAs of G. mirabilis and G. seta revealed four differences in nucleotide sequence in the coding region, but all nucleotide substitutions were synonymous. The identical deduced primary structures of the two enzymes suggested the possibility of different protein conformational variants ('conformers') in the two species. This hypothesis is supported by electrospray ionization mass spectrometry, which indicates that the masses of the A4-LDH orthologues of the two species are the same within the resolution of the technique. To explore the possibility that the two enzymes were different conformers of the same primary structure, we treated purified G. seta and G. mirabilis A4-LDHs with 3.0 mol l-1 urea or 6 mol l-1 guanidine&shy;HCl and, after removing the denaturant, compared their kinetic properties and heat stabilities. Neither treatment had an effect on the A4-LDH of G. mirabilis, but both converted the Km versus temperature profile of the G. seta enzyme to that of the G. mirabilis A4-LDH. The thermal stability of neither enzyme was affected. We propose, as has been suggested in several previous studies of A4-LDH, that this enzyme can fold into a number of conformers with different stabilities and functional properties. The A4-LDH of G. seta furnishes evidence that such conformers may provide an important mechanism for adaptation of proteins to temperature.

Cancer risks in two large breast cancer families linked to BRCA2 on chromosome 13q12-13

The penetrance of the BRCA2 gene on chromosome 13q12-13 has been estimated in two large, systematically ascertained, linked families, by use of a maximum-likelihood method to incorporate both cancer-incidence data and 13q marker typings in the families. The cumulative risk of breast cancer in female gene carriers was estimated to be 59.8% by age 50 years (95% confidence interval [95% CI] 25.9%-78.5%) and 79.5% by age 70 years (95% CI 28.9%-97.5%). The cumulative risk of breast cancer in male carriers was estimated to be 6.3% (95% CI 1.4%-25.6%) by age 70 years. There was no evidence of any risk difference between the two families. These results indicate that the lifetime breast cancer risk in BRCA2 carriers, for at least a subset of mutations, is comparable to that for BRCA1. A significant excess of ovarian cancer in gene carriers was observed (relative risk 17.69, based on three cases), but the absolute risk of ovarian cancer was less than that reported for BRCA1. Significant excesses of laryngeal cancer (relative risk 7.67, based on two possible carriers) and prostate cancer (relative risk 2.89, based on five possible carriers) were also observed. One case of ocular melanoma, as well as a second eye cancer of unspecified histology, occurred in obligate gene carriers.

Control of T lymphocyte signal transduction through clonal anergy

Stimulation of interleukin-2 producing T lymphocytes via the T cell receptor (TCR) complex in the absence of other costimulatory factor results paradoxically not in activation but in an unresponsive state termed clonal anergy. T cell anergy appears to be a mechanism by which potentially autoreactive T lymphocytes are inactivated in the periphery, thus maintaining tolerance to self antigens. The breakdown of such tolerance may result in autoimmune diseases. In contrast, induction of peripheral tolerance is the ultimate goal in organ transplantation and is a potential mechanism by which a growing tumor evades immune destruction. The anergic state is characterized by an inability to secrete interleukin-2 and proliferate following restimulation via the TCR even in the presence of constimulatory factors. Recent studies have demonstrated a specific block in Ras activation in anergic T lymphocytes. This defect is correlated with a failure to activate the downstream effectors Erk and Jnk and a lack of activation of the AP-1 transcription factor complex, offering a plausible mechanism for the inability to initiate interleukin-2 gene transcription in the anergic state.

Expression of SQ10 (a preprorelaxin-like gene) in the pregnant rabbit placenta and uterus

A Northern blot containing poly(A)+ RNA isolated from pregnant rabbit placenta, uterus, ovary, mammary gland, psoas muscle, and intestine was hybridized with an oligonucleotide probe to porcine preprorelaxin. Only the placenta and uterus exhibited high levels of a 1-kb mRNA that hybridized to the probe. Porcine preprorelaxin primers were used to generate and amplify cDNAs from placental and uterine poly(A)+ RNA. Southern blot analysis of the placental and uterine cDNAs each revealed a single PCR product that hybridized with the porcine relaxin probe. The sequence of the cDNAs exhibited 100% identity with SQ10, a preprorelaxin-like gene identified in rabbit tracheobronchial epithelial cells. Identical results were obtained with primers specific for SQ10. SQ10 is expressed in tracheobronchial epithelial cells during abnormal conditions, such as mechanical or toxic injury. The protein is believed to have a role in tracheal epithelial cell differentiation and transformation that occurs under the above conditions. This work shows, for the first time, the presence of high levels of message for SQ10 in normal reproductive tissues. The expression of SQ10 in the uterus and placenta may suggest an important role in cell differentiation and transformation that occurs in these tissues during pregnancy.

Induction of lytic pathways in T cell clones derived from wild-type or protein tyrosine kinase Fyn mutant mice

The OVA-reactive CD4+ Th1 clones and alloreactive CD8+ clones derived from wild-type or fyn-/- mice serve as model systems which have allowed us to investigate several aspects of the molecular events associated with T cell-mediated cytotoxicity, including 1) the differential utilization of two distinct cytolytic pathways by CD4+ Th1 clones and CD8+ CTL, 2) a comparison of the pathways of lysis induced by stimulation of the TCR or by alternative stimuli, 3) the requirement of Fyn for derivation of antigen-specific T-cell clones having properties of CD4+ Th1 and CD8+ CTL cells 4) the differential requirement of Fyn in the induction of responses by TCR and the alternative stimuli. Stimulation through the TCR, either by APC bearing relevant antigen or by immobilized anti-CD3 mAb, resulted in comparable levels of target cell lysis by clones from both wild-type and fyn-/- mice. These clones also utilize the Fas pathway to lyse target cells. Thus, Fyn does not appear to be required for expression of the Fas pathway when triggered through the TCR. In contrast, lysis of target cells by T-cell clones lacking Fyn was deficient when stimulated through Thy-1 or Ly-6C (using mAb) or with Con A or phorbol ester as compared to clones derived from wild-type mice. The basis for the defect in response to stimulation through the GPI-linked molecules appears to be a signaling defect which affects all of the functional responses we measured, while the defect in response to Con A stimulation appears to affect lysis but not lymphokine production. Thus, Fyn expression is selectively required for efficient activation of the Fas pathway of lysis through Thy-1, Ly-6C, and by Con A or phorbol ester in these T-cell clones. CD8+ clones derived from fyn-/- mutant mice, like clones derived from wild-type mice, display antigen-specific lysis, and appear to express perforin message and perforin protein. A Ca(++)-dependent (presumably perforin/exocytosis) component and Fas component of lysis was detected in CD8+ clones derived from fyn-/- mutant mice. Thus, Fyn is not required for expression of these components of antigen specific lysis by CD8+ alloreactive CTL clones. It appears that CD8+ clones that use multiple lytic mechanisms may selectively employ the perforin or Fas-based pathway depending on properties of the target cell or stimulus.(ABSTRACT TRUNCATED AT 400 WORDS)

Induction of the increased Fyn kinase activity in anergic T helper type 1 clones requires calcium and protein synthesis and is sensitive to cyclosporin A

Several alterations in T cell receptor-associated signal transduction have been observed following induction of anergy of T helper type 1 (Th1) clones, including a modified intracellular free calcium ([Ca2+]i) response and increased kinase activity associated with the protein tyrosine kinase p59fyn. In the current study, we demonstrate that, although the kinetics of acquisition of both of these signaling alterations correlated with the generation of anergy, a normal calcium response returned within 48 h after removal from the anergizing stimulus, whereas the increased p59fyn activity persisted and the cells remained hyporesponsive. Generation of both the anergic state and the increased p59fyn activity was prevented in the presence of calcium-free medium, cycloheximide (CHX), or cyclosporin A (CsA), and could be mimicked by the calcium ionophore ionomycin. In contrast, the altered calcium response was inhibited by stimulation in the presence of calcium-free medium or CsA, but not CHX. Thus, surprisingly, these data suggest that a chronic elevation of [Ca2+]i is proximal to and necessary for the increase in p59fyn-associated kinase activity observed in anergic Th1 clones. Increased p59fyn activity, but not the altered calcium response, correlates with maintenance of the anergic state.

Differential requirement for protein tyrosine kinase Fyn in the functional activation of antigen-specific T lymphocyte clones through the TCR or Thy-1

The protein tyrosine kinase Fyn has been shown to be involved in signal transduction through the TCR and the glycosyl-phosphatidylinositol-linked surface molecule Thy-1 expressed on T cells. In this study, we examine the requirement for Fyn expression in signaling through the TCR or Thy-1 using a panel of Ag-specific T cell clones derived from fyn-/- mutant mice. These clones do not express normal Fyn protein, as measured by immune-complex kinase reaction using anti-Fyn Ab. Stimulation through the TCR, either by APC bearing relevant Ag or by immobilized anti-CD3 mAb, resulted in comparable levels of proliferation, lymphokine production, and cytolysis by clones from both wild-type and fyn-/- mice. In contrast, stimulation through Thy-1, using soluble (or cross-linked) anti-Thy-1 mAb, was deficient, as measured by these responses. Thus, Fyn expression is selectively required for functional activation through Thy-1 in these T cell clones.

Differential requirement for protein tyrosine kinase Fyn in the functional activation of antigen-specific T lymphocyte clones through the TCR or Thy-1

The protein tyrosine kinase Fyn has been shown to be involved in signal transduction through the TCR and the glycosyl-phosphatidylinositol-linked surface molecule Thy-1 expressed on T cells. In this study, we examine the requirement for Fyn expression in signaling through the TCR or Thy-1 using a panel of Ag-specific T cell clones derived from fyn-/- mutant mice. These clones do not express normal Fyn protein, as measured by immune-complex kinase reaction using anti-Fyn Ab. Stimulation through the TCR, either by APC bearing relevant Ag or by immobilized anti-CD3 mAb, resulted in comparable levels of proliferation, lymphokine production, and cytolysis by clones from both wild-type and fyn-/- mice. In contrast, stimulation through Thy-1, using soluble (or cross-linked) anti-Thy-1 mAb, was deficient, as measured by these responses. Thus, Fyn expression is selectively required for functional activation through Thy-1 in these T cell clones.

A large kindred with 17q-linked breast and ovarian cancer: genetic, phenotypic, and genealogical analysis

BACKGROUND

Mutation of a specific, but as yet unidentified, gene BRCA1 on chromosome 17q results in increased susceptibility to breast and ovarian cancer. It is important to know the effects of this gene in terms of the age-specific risks of these cancers and the potential interaction of this gene with other known risk factors.

PURPOSE

We performed detailed studies on a large multigenerational family, in which there is known 17q-linked breast and ovarian cancer, in order to characterize the effects of the BRCA1 mutation on development of breast and ovarian cancer.

METHODS

Data from the Utah Population Database were used to identify a family (identified as K2082) with a cluster of premenopausal breast cancer and ovarian cancer at any age. Blood samples from 195 members of the family were obtained and these individuals were genotyped for a series of four chromosome 17q polymorphic markers. Information on reproductive history, cancer incidence and treatment, and lifestyle factors was collected on 72 women in the family by questionnaire or through contact with living relatives.

RESULTS

Odds in favor of linkage of breast and ovarian cancer in this family to the BRCA1 region of chromosome 17q are greater than 10(8) to 1. The estimated risks for breast or ovarian cancer because of the BRCA1 mutation in this family are 40% by age 50 years and 90% by age 70. No differences between affected and unaffected older BRCA1 gene carriers were observed for a number of known epidemiologic risk factors for these cancers. The gender of the parent from whom the mutant BRCA1 allele was inherited was significantly associated with phenotypic expression (P = .04). A recombinant which places BRCA1 distal to the marker Mfd191 was observed.

CONCLUSIONS

Women with the BRCA1 mutation are at increased risk of developing breast and ovarian cancer. In our study population, the mutation appears to confer a lower risk of cancer at younger ages than found in previous studies. Continued interaction with family K2082 will be useful in longitudinal follow-up studies and in studies of the psychosocial implications of providing DNA diagnosis of BRCA1.

Anergic T-lymphocyte clones have altered inositol phosphate, calcium, and tyrosine kinase signaling pathways

Full activation of TH1 helper T lymphocytes requires ligation of the specific T-cell antigen receptor (TCR) and a second signal provided by costimulator molecule(s) expressed on particular antigen-presenting cells. Stimulation via the TCR complex alone generates a subsequent unresponsive state characterized by an inability to produce interleukin 2. We report here that such anergic cells exhibit multiple alterations in TCR-associated signaling. The basal levels of intracellular free calcium and phosphatidylinositol 1,4,5-trisphosphate are elevated in anergic cells, and the levels fail to increase significantly upon subsequent restimulation. Examination of phospholipase C-gamma 1 reveals evidence for post-translational modification, correlating with increased tyrosine phosphorylation of the molecule. Tyrosine phosphorylation of additional substrates identified from whole-cell lysates also is altered compared to untreated cells, suggesting a modification in net tyrosine kinase activity. Although the level of kinase activity present in TCR/CD3 or Lck immunoprecipitates is modestly altered after induction of anergy, there is a dramatic increase in specific Fyn-associated tyrosine kinase activity in anergic cells and increased phosphorylation of a 110-kDa protein that is coimmunoprecipitated with Fyn. These results are consistent with a model in which anergic TH1 lymphocytes display a fundamental alteration in TCR-mediated tyrosine kinase activity, associated with changes in phospholipase C-gamma 1, inositol phosphates, and intracellular free calcium.

Irreversible blindness in systemic lupus erythematosis

We describe a patient with systemic lupus erythematosis and renal involvement and who developed visual impairment in the absence of hypertension and anti-cardiolipin antibodies. This was attributed to occlusive vascular disease and choroidal infarction in the context of active lupus. Complete and irreversible blindness developed rapidly despite treatment and the patient died of cerebral haemorrhage 2 months after discharge.

Chromosome 17q linkage studies of 18 Utah breast cancer kindreds

In this paper we present linkage results from the analysis of 18 Utah breast cancer kindreds, for three 17q markers. Four kindreds had LOD scores greater than 1.0 for at least one of the marker loci. One of these kindreds has a LOD score of 6.07 with D17S579, and we believe it to be the most informative 17q family reported to date. Among the kindreds which appear unlinked to 17q were an early-onset breast cancer family, a large breast-ovarian family, and a kindred with mixed age at onset. Analysis of individual recombinants in the linked families localizes the BRCA1 gene between THRA1 and D17S579 (Mfd188). A comparison of the Cancer and Steroid Hormone Study (CASH) model and a model which assumes a rare dominant susceptibility locus with low penetrance and no phenocopies stresses the difficulties in assessing linkage if the assumptions of the CASH model in terms of age at onset of breast cancer are not appropriate for the BRCA1 locus. A hypothetical breast cancer pedigree is used to calculate gene carrier probabilities under the CASH model, thereby illustrating some of our concerns regarding the use of this model to detect and exclude 17q linkage in breast cancer families.

Screening for tuberculosis: current practices and attitudes of hospital workers

To examine the current practices and attitudes of health workers to the prevention of tuberculosis in our 55-bed chest unit, we investigated the tuberculin reactor status, reviewed pre-employment screening and reviewed the action taken after contact with tuberculosis by staff members. We assessed all 61 staff members, including 44 nurses, 1 physiotherapist, 11 doctors and 5 domestic workers. 47/61 staff members had had BCG vaccination. Heaf testing revealed 3 Heaf-negative subjects and, of the remainder, 52 had grade 3 or stronger reactions. Only 3/11 doctors, 36/44 nurses and 4/5 domestic workers had had any pre-employment screening. No action was taken by any doctor after their last contact with tuberculosis, whereas 10/44 nurses and 3/5 domestic workers had had chest X-rays. This study shows the low importance with which the risk of tuberculosis is perceived, particularly by doctors and demonstrates the need for stricter supervision and improved quality of pre-employment screening.

An evaluation of antenatal fetal acoustic stimulation

Fetal heart rate reactivity was evaluated following acoustic stimulation testing (AST). The AST and NST (non-stress test) were compared with regards to certain adverse perinatal outcome criteria, and in a selected sample of cases, to other surveillance tests. These tests were the oxytocin challenge test (OCT) and biophysical profile (BPP). 479 tests were performed on 240 high-risk patients. The AST significantly increased fetal heart rate reactivity. With regards adverse perinatal outcome criteria, there was no significant difference between the AST and NST in relation to sensitivity, specificity or predictive values. In the 38 patients with both non-reactive NSTs and reactive ASTs, 5 (13.5%) had immediate follow-up surveillance tests (OCTs and/or BPPs) that were non-reassuring and necessitated delivery. In four of the five cases, there was evidence of potential fetal compromise. These preliminary observations suggest that the AST may have evoked reactivity in fetuses with early compromise, and raise concerns about replacing the NST with the AST as a primary screening test of fetal well-being.