The efficacy of chemotherapy is limited by intratumoral senescent cells expressing PD-L2

Chemotherapy often generates intratumoral senescent cancer cells that strongly modify the tumor microenvironment, favoring immunosuppression and tumor growth. We discovered, through an unbiased proteomics screen, that the immune checkpoint inhibitor programmed cell death 1 ligand 2 (PD-L2) is highly upregulated upon induction of senescence in different types of cancer cells. PD-L2 is not required for cells to undergo senescence, but it is critical for senescent cells to evade the immune system and persist intratumorally. Indeed, after chemotherapy, PD-L2-deficient senescent cancer cells are rapidly eliminated and tumors do not produce the senescence-associated chemokines CXCL1 and CXCL2. Accordingly, PD-L2-deficient pancreatic tumors fail to recruit myeloid-derived suppressor cells and undergo regression driven by CD8 T cells after chemotherapy. Finally, antibody-mediated blockade of PD-L2 strongly synergizes with chemotherapy causing remission of mammary tumors in mice. The combination of chemotherapy with anti-PD-L2 provides a therapeutic strategy that exploits vulnerabilities arising from therapy-induced senescence.

Cellular Senescence Is Immunogenic and Promotes Antitumor Immunity

Cellular senescence is a stress response that activates innate immune cells, but little is known about its interplay with the adaptive immune system. Here, we show that senescent cells combine several features that render them highly efficient in activating dendritic cells (DC) and antigen-specific CD8 T cells. This includes the release of alarmins, activation of IFN signaling, enhanced MHC class I machinery, and presentation of senescence-associated self-peptides that can activate CD8 T cells. In the context of cancer, immunization with senescent cancer cells elicits strong antitumor protection mediated by DCs and CD8 T cells. Interestingly, this protection is superior to immunization with cancer cells undergoing immunogenic cell death. Finally, the induction of senescence in human primary cancer cells also augments their ability to activate autologous antigen-specific tumor-infiltrating CD8 lymphocytes. Our study indicates that senescent cancer cells can be exploited to develop efficient and protective CD8-dependent antitumor immune responses.

SIGNIFICANCE

Our study shows that senescent cells are endowed with a high immunogenic potential-superior to the gold standard of immunogenic cell death. We harness these properties of senescent cells to trigger efficient and protective CD8-dependent antitumor immune responses. See related article by Chen et al., p. 432. This article is highlighted in the In This Issue feature, p. 247.

Cellular Senescence Is Immunogenic and Promotes Antitumor Immunity

Cellular senescence is a stress response that activates innate immune cells, but little is known about its interplay with the adaptive immune system. Here, we show that senescent cells combine several features that render them highly efficient in activating dendritic cells (DC) and antigen-specific CD8 T cells. This includes the release of alarmins, activation of IFN signaling, enhanced MHC class I machinery, and presentation of senescence-associated self-peptides that can activate CD8 T cells. In the context of cancer, immunization with senescent cancer cells elicits strong antitumor protection mediated by DCs and CD8 T cells. Interestingly, this protection is superior to immunization with cancer cells undergoing immunogenic cell death. Finally, the induction of senescence in human primary cancer cells also augments their ability to activate autologous antigen-specific tumor-infiltrating CD8 lymphocytes. Our study indicates that senescent cancer cells can be exploited to develop efficient and protective CD8-dependent antitumor immune responses.

SIGNIFICANCE

Our study shows that senescent cells are endowed with a high immunogenic potential-superior to the gold standard of immunogenic cell death. We harness these properties of senescent cells to trigger efficient and protective CD8-dependent antitumor immune responses. See related article by Chen et al., p. 432. This article is highlighted in the In This Issue feature, p. 247.

Cellular senescence enhances adaptive anticancer immunosurveillance

Cancer therapy often induces senescence in some cancer cells. Senescent cells, due to their profoundly altered biology, may conceivably interact with the adaptive immune system in novel ways that may boost cancer immunosurveillance, triggering the clearance of both senescent and non-senescent neoplastic cells. In this regard, we have recently reported that senescent cancer cells exhibit potent antigenicity and adjuvanticity and can elicit strong CD8⁺ T cell-dependent anticancer effects when used as vaccination agents.

The lysosomal proteome of senescent cells contributes to the senescence secretome

Senescent cells accumulate in tissues over time, favoring the onset and progression of multiple age-related diseases. Senescent cells present a remarkable increase in lysosomal mass and elevated autophagic activity. Here, we report that two main autophagic pathways macroautophagy (MA) and chaperone-mediated autophagy (CMA) are constitutively upregulated in senescent cells. Proteomic analyses of the subpopulations of lysosomes preferentially engaged in each of these types of autophagy revealed profound quantitative and qualitative changes in senescent cells, affecting both lysosomal resident proteins and cargo proteins delivered to lysosomes for degradation. These studies have led us to identify resident lysosomal proteins that are highly augmented in senescent cells and can be used as novel markers of senescence, such as arylsulfatase ARSA. The abundant secretome of senescent cells, known as SASP, is considered their main pathological mediator; however, little is known about the mechanisms of SASP secretion. Some secretory cells, including melanocytes, use the small GTPase RAB27A to perform lysosomal secretion. We found that this process is exacerbated in the case of senescent melanoma cells, as revealed by the exposure of lysosomal membrane integral proteins LAMP1 and LAMP2 in their plasma membrane. Interestingly, a subset of SASP components, including cytokines CCL2, CCL3, CXCL12, cathepsin CTSD, or the protease inhibitor SERPINE1, are secreted in a RAB27A-dependent manner in senescent melanoma cells. Finally, proteins previously identified as plasma biomarkers of aging are highly enriched in the lysosomes of senescent cells, including CTSD. We conclude that the lysosomal proteome of senescent cells is profoundly reconfigured, and that some senescent cells can be highly active in lysosomal exocytosis.

Gastric gas dynamics in healthy humans

BACKGROUND

To cope with the daily increments of gastric gas, the stomach can propel gas to the small bowel or trigger the belching reflex. Our aim was to evaluate transit of free gastric gas in healthy humans, and its relationship with abdominal symptoms.

METHODS

In 24 healthy volunteers a gas mixture was infused into the stomach at 0 mL/min (sham infusion), 25 mL/min, 50 mL/min, and 100 mL/min (n = 6 each) up to 1500 mL. Belching, rectal gas evacuation, and abdominal perception were continuously recorded for 90 min.

KEY RESULTS

Sham infusion was associated to low rectal gas evacuation (187 ± 94 mL after 90 min), and belching (0 ± 0). In contrast, gastric gas infusion increased rectal gas evacuation (1198 ± 176 mL; P = .025) and belching (4 ± 1 belches; P = .0520) without differences between the infusion rates tested. Overall, there was a negative correlation between rectal gas evacuation and belching (r = -.72; P < .0001): 6 subjects had frequent belching (14 ± 2 belches) and minor rectal gas evacuation (330 ± 112 mL), whereas 12 subjects had virtually no belches (1 ± 1 belches) and greater rectal gas evacuation (1630 ± 147 mL; P < .001 vs belchers for both). Gas infusion induced lower abdominal symptoms in belchers (score increment 0.7 ± 0.3) than in rectal gas evacuators (score increment 1.7 ± 0.5; P = .033).

CONCLUSIONS AND INFERENCES

An excellent balance between belching and distal gastric empting allows the stomach to adapt to great variations in gas intake. In general, most gastric gas is emptied to distal intestinal segments, but in some circumstances gastric gas induces belching, a mechanism that may improve gas tolerance.

COXI based phylogenetic analysis of Caucasian clade of European Troglocaris (Crustacea: Decapoda: Atyidae) with the suggestion of a new taxonomic group structure

New genetic data on Caucasian troglobiotic shrimps collected from the territory of Russia, Abkhazia and Western Georgia are presented. Based on new genetic data on the marker region of subunit I of cytochrome oxidase of mitochondrial DNA (COXI mtDNA) of Caucasian species and other taxa of European cave shrimps (Troglocaris s.l.) from GenBank (NCBI) database, a new generic structure is presented. Based on a significant genetic divergence of COXI mtDNA subgenera of Troglocaris s.l., namely Troglocaris s.s., Xiphocaridinella and Spelaeocaris, should be considered as separate genera while Troglocaris (Troglocaridella) hercegovinensis (Babić, 1922) is suggested to be transferred within Dinaric genus Spelaeocaris as Spealeocaris hercegovinensis (Babić, 1922) comb. nov. Besides, Troglocaris bosnica shows a significant a genetic difference (at the level of the separate genus) from the remaining representatives of the genus Troglocaris s.s. Moreover, p-distances (COXI) of about 17% are supposed for generic separation within European Troglocaris-related atyid shrimps and 5% for separation of cryptic species within Caucasian Xiphocaridinella. A list of all known taxa of Troglocaris-related atyid shrimps of the European part and a discussion of the general distribution of troglocaridid atyid shrimps in the Balkans and the Caucasus are presented. A new version of divergence events between Dinaric–Caucasian Troglocaris lineages (genera) based on new genetic data is suggested.

Anxiety can significantly explain bolus perception in the context of hypotensive esophageal motility: Results of a large multicenter study in asymptomatic individuals

BACKGROUND

Previous studies have not been able to correlate manometry findings with bolus perception. The aim of this study was to evaluate correlation of different variables, including traditional manometric variables (at diagnostic and extreme thresholds), esophageal shortening, bolus transit, automated impedance manometry (AIM) metrics and mood with bolus passage perception in a large cohort of asymptomatic individuals.

METHODS

High resolution manometry (HRM) was performed in healthy individuals from nine centers. Perception was evaluated using a 5-point Likert scale. Anxiety was evaluated using Hospitalized Anxiety and Depression scale (HAD). Subgroup analysis was also performed classifying studies into normal, hypotensive, vigorous, and obstructive patterns.

KEY RESULTS

One hundred fifteen studies were analyzed (69 using HRM and 46 using high resolution impedance manometry (HRIM); 3.5% swallows in 9.6% of volunteers were perceived. There was no correlation of any of the traditional HRM variables, esophageal shortening, AIM metrics nor bolus transit with perception scores. There was no HRM variable showing difference in perception when comparing normal vs extreme values (percentile 1 or 99). Anxiety but not depression was correlated with perception. Among hypotensive pattern, anxiety was a strong predictor of variance in perception (R² up to .70).

CONCLUSION AND INFERENCES

Bolus perception is less common than abnormal motility among healthy individuals. Neither esophageal motor function nor bolus dynamics evaluated with several techniques seems to explain differences in bolus perception. Different mechanisms seem to be relevant in different manometric patterns. Anxiety is a significant predictor of bolus perception in the context of hypotensive motility.

Normal values of esophageal pressure responses to a rapid drink challenge test in healthy subjects: results of a multicenter study

BACKGROUND

Multiple water swallow is increasingly used as a complementary challenge test in patients undergoing high-resolution manometry (HRM). Our aim was to establish the range of normal pressure responses during the rapid drink challenge test in a large population of healthy subjects.

METHODS

Pressure responses to a rapid drink challenge test (100 or 200 mL of water) were prospectively analyzed in 105 healthy subjects studied in nine different hospitals from different countries. Esophageal motility was assessed in all subjects by solid-state HRM. In 18 subjects, bolus transit was analyzed using concomitant intraluminal impedance monitoring.

KEY RESULTS

A virtually complete inhibition of pressure activity was observed during multiple swallow: Esophageal body pressure was above 20 mm Hg during 1 (0-8) % and above 30 mm Hg during 1 (0-5) % of the swallow period, and the pressure gradient across the esophagogastric junction was low (-1 (-7 to 4) mm Hg). At the end of multiple swallow, a postswallow contraction was evidenced in only 50% of subjects, whereas the remaining 50% had non-transmitted contractions. Bolus clearance was completed after 7 (1-30) s after the last swallow, as evidenced by multichannel intraluminal impedance.

CONCLUSIONS & INFERENCES

The range of normal pressure responses to a rapid drink challenge test in health has been established in a large multicenter study. Main responses are a virtually complete inhibition of esophageal pressures with a low-pressure gradient across esophagogastric junction. This data would allow the correct differentiation between normal and disease when using this test.

New blends of ethylene-butyl acrylate copolymers with thermoplastic starch. Characterization and bacterial biodegradation

Ethylene-butyl acrylate copolymer (EBA) with 13% of butyl acrylate content was used to produce blends with 10, 30 and 60% of thermoplastic starch (TPS) plasticized with glycerol. Ethylene-acrylic acid copolymer (EAA) was used as compatibilizer at 20% content with respect to EBA. The blends were characterized by X-ray diffraction, ATR-Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM), water-Contact Angle measurements (CA), Differential Scanning Calorimetry (DSC) and Stress-strain mechanical tests. Initiated autoxidation of the polymer blends was studied by chemiluminescence (CL) confirming that the presence of the polyolefin-TPS interphase did not substantially affect the oxidative thermostability of the materials. Three bacterial species have been isolated from the blend films buried in soil and identified as Bacillus subtilis, Bacillus borstelensis and Bacillus licheniformis. Biodegradation of the blends (28days at 45°C) was evaluated by carbon dioxide measurement using the indirect impedance technique.

Patterns of esophageal pressure responses to a rapid drink challenge test in patients with esophageal motility disorders

BACKGROUND

Multiple rapid swallow has been proposed as a challenge test that can help diagnosis and management of patients with esophageal motility disorders. Our aim was to characterize specific pressure patterns in response to a rapid drink challenge test in patients with esophageal motility disorders, and to determine the potential of these patterns in the diagnosis of patients with esophageal symptoms but normal single swallow manometry.

METHODS

Pressure responses to a rapid drink challenge test (rapid swallow of 200 mL water) were prospectively analyzed in 30 healthy controls and 285 patients with esophageal symptoms: 33 achalasia, 68 hypocontractile motility, 27 hypercontractile motility and 160 patients with normal manometry.

KEY RESULTS

Three different patterns of responses were characterized: (i) hypopressive or normal pattern that was shared by healthy subjects and patients with hypocontractile peristalsis, and discriminated patients with non-obstructive hypercontractile motility or achalasia (p < 0.001; sensitivity 80% and specificity 93%), (ii) brief hyperpressive pattern observed in patients with non-obstructive hypercontractile disorders (distal spasm and hypercontractile esophagus), and (iii) prolonged hyperpressive pattern, that discriminated achalasia from patients with non-obstructive hypercontractile disorders (p < 0.001; sensitivity 70% and specificity 85%). Seventeen percent of patients with esophageal symptoms but normal single swallow manometry had abnormal responses to the drink challenge test: 14% a brief hyperpressive pattern, and 3% a prolonged hyperpressive pattern.

CONCLUSIONS & INFERENCES

Specific patterns of responses to a rapid drink challenge test could help identification of motility disorders in patients with esophageal symptoms but unclear or normal esophageal manometry.

Angiofluorographic aspects in age-related macular degeneration

Although AMD (age-related macular degeneration) has been described for over 100 years, there is neither a standard agreement on the definition of specific lesions nor a generally accepted classification system. For example, the age limits for AMD varied widely in different clinical studies; the methods used for examination also vary (visual acuity, perimetry, contrast sensitivity, slit lamp examination of the fundus, retinal photography, fluorescein angiography, indocyanine green angiography). We described the multitude of angiofluorographic aspects in patients with AMD and conceived a classification to be easily used in clinical practice. Although a detailed ophthalmoscopy can often identify the characteristic lesions of AMD, a complete picture is obtained by fluorescein angiography. The angiographic classification of AMD is structured similarly to the clinical one. It has two main patterns, non-exudative and exudative lesions, but it provides more information about the nature of the lesions. In the last three decades, an impressive amount of information regarding the prevalence, progression and risk factors for AMD has been published. The source of this information is mainly represented by the large population studies that are often multicenter studies. Recognizing the clinical signs of AMD and classifying them into different stages is important for the prognosis and the therapeutical decision, but also for conceiving study protocols.

Mutation of the dyslexia-associated gene Dcdc2 impairs LTM and visuo-spatial performance in mice

Developmental reading disorder (RD) affects 5-10% of school aged children, with a heritability of approximately 60%. Genetic association studies have identified several candidate RD susceptibility genes, including DCDC2; however, a direct connection between the function of these genes and cognitive or learning impairments remains unclear. Variants in DCDC2, a member of the doublecortin family of genes, have been associated in humans with RD and ADHD and Dcdc2 may play a role in neuronal migration in rats. In this study, we examined the effect of Dcdc2 mutation on cognitive abilities in mice using a visual attention and visuo-spatial learning and memory task. We show that both heterozygous and homozygous mutations of Dcdc2 result in persistent visuo-spatial memory deficits, as well as visual discrimination and long-term memory deficits. These behavioral deficits occur in the absence of neuronal migration disruption in the mutant mice, and may be comorbid with an anxiety phenotype. These are the first results to suggest a direct relationship between induced mutation in Dcdc2 and changes in behavioral measures. Dcdc2 mutant mice should prove useful in future studies designed to further dissect the underlying neural mechanisms that are impaired following Dcdc2 mutation.

Gallstone ileus: analysis of eight cases and review of the literature

OBJECTIVE

We hereby analyzed a series of gallstone ileus cases operated on in our department starting from a Bouveret syndrome case.

METHOD

Retrospective analysis of all gallstone ileus cases who underwent surgery in our department during the last 26 years. We took into consideration diagnostic elements, time from admission to surgery, type of surgery and post-operative outcome.

RESULTS

During this period 9,143 gallstones were deferred to surgery; 27 biliary-digestive fistulae were discovered during surgery; gallstone ileus complicated fistula in 8 patients. Gallstone ileus was exclusively present in elderly women with associated comorbidities. Diagnosis was suggested by clinical features of acute or incomplete intestinal obstruction; it was sustained by imagistic studies with different degrees of relevance. The average time from admission to surgery was 2.6 days. Surgical approach varied from simple enterolithotomy to additional fistula repair. The outcome was uneventful in most of the cases with only one exception.

CONCLUSIONS

gallstone ileus is a rare condition, occurring in elders with important comorbidities. The choice for surgical procedure depends on the obstructive syndrome's gravity and associated comorbidities; the type of intervention does not significantly influence post-operative morbidity and mortality rates.

[The gastric plasmacytoma--a case report]

The gastric plasmacytoma represents a rarely encountered, so that, the diagnosis criteria, the medical attitude and the evolution of this disease are less coded. It is known the fact that this tumours, extramedullary plasmacytomas with gastric localization, develop in soft submucous tissue, therefore it's very difficult or even impossible preoperative diagnosis through an upper endoscopy including biopsy. We present the case of a 54 years old patient, with no significant pathological personal record, that was admitted in our Clinic for having melenic dark stools which have repeated within a 6 months period prior to this hospitalisation. Repeated gastric mucosal samples taken in another medical unit shown normal aspects, contrary to all imaging testing (e.g. ultrasonography, upper endoscopy and barium swallow) which revealed a tumor mass of considerable extent at the level of the gastric corpus. First-line therapy was gastric resection followed by radiotherapy, because it is well known that the tumour is highly radiosensitive. The patient's postoperative course was satisfactory, showing no signs or recurrence 6 months after surgery at upper endoscopy and CT-scan.

[Dobutamine exercise echocardiography versus SPECT in diagnosing ischemic heart disease]

The aim of the study was comparison of dobutamine stress echocardiography with SPECT in the assessment of ischemic heart disease.

METHODS

It is a retrospective study analysing 119 patients (72 women and 47 men, mean age 56.9 +/- 10.68 years), who underwent dobutamine stress echocardiography and SPECT. Because of inconclusive findings (LBBB, decreased myocardial perfusion by SPECT depending on the position of the body), 23 patients were excluded.

RESULTS

In the whole group of 96 patients the diagnostic validity of dobutamine stress echocardiography was as follows: sensitivity 78%, specificity 93%, positive predictive value 89%, negative predictive value 85%, and kappa value 0.71. In women the sensitivity was 69%, specificity 93%, positive predictive value 79%, negative predictive value 89%, and kappa value 0.64. In men the diagnostic validity was: sensitivity 83%, specificity 92%, positive predictive value 95%, negative predictive value 73%, and kappa value 0.70.

CONCLUSION

In conclusion, dobutamine stress echocardiography is highly sensitive and specific method in the diagnosis of ischemic heart disease with good agreement when compared with SPECT. Because of availability and lower cost in comparison with SPECT, dobutamine stress echocardiography is an optimal method in the diagnosis and management of patients with ischemic heart disease in routine clinical practice.

Humoral and cellular monitoring to predict the development of infection in Crohn's disease patients beginning treatment with infliximab

Although severe infectious complications are rare, it is important to properly screen patients for predisposing conditions before beginning treatment with infliximab. We assessed immunity markers that might provide prognostic value for the development of infection in Crohn's disease patients after treatment with infliximab. In a prospective study, 34 fistulizing Crohn's disease patients (mean age 37 years) were studied. Patients were scheduled to receive three infusions of infliximab (5 mg/kg) at weeks 0, 2, and 6. Immunologic studies: Serum immunoglobulin (IgG, IgA, IgM), IgG-subclasses, and complement (C3, C4, factor B) determined by nephelometry; CD3+, CD3+CD4+, CD3+CD8+, CD19+, and CD56+CD3- lymphocyte subsets performed by flow cytometry. During a mean follow-up of 56 months, 1 patient had disseminated tuberculosis and 2 patients had severe bacterial infections. The presence of infection was associated with significantly higher IgM (246 vs. 121 mg/dL; Mann-Whitney test, P = 0.01), lower C3 (64 vs. 118, P = 0.02), lower C4 concentrations (12 vs. 25, P = 0.02), and with decreased levels of CD19 B cells (47 vs. 290, P = 0.03) in the baseline study. Further prospective studies in a larger number of patients are suggested to examine whether early monitoring of immunocompetence might help to identify the risk of infection in patients treated with infliximab.

[Management of biliary fistulas in surgery for hepatic hydatid cyst]

One of the most important problems of the surgical treatment of the hydatid disease of the liver is the remaining cavity of the cyst. Its evolution is mainly decided by the existence and the debit of a biliary fistula. During 10 years (1997-2006), 138 patients with 166 hydatid cysts of the liver were admitted and operated in our clinic. Among them, 57 cysts had a biliary fistula, found during the operation, while in 11 other patients the fistula became obvious 1 or 2 days after the procedure. The incidence of biliary fistulas (68 of 166 cases, which means 41%) is higher, due to the location of the cysts, mainly in the central parts of the liver. There were 44 (65%) low debit fistulas and 24 (35%) high debit fistulas. Our surgical attitude regarding the cavities with biliary fistulas has considerably changed; while between 1997-2000 an anastomosis with a Y or Omega jejunal loop was the most frequent technique, nowadays we use the external drainage of the cavity, associated to endoscopic sphincterotomy, for fistulas with large volumes (more than 300 ml/day) and/or persistent. Whenever it is possible, we practice the direct suture of the biliary fistula.

Predictive value of clinical and microbiological parameters for the treatment outcome of scaling and root planing

OBJECTIVES

To compare the clinical and microbiological outcome of non-surgical periodontal therapy after 6 months with data obtained after hygienic phase or 6 weeks after completion of non-surgical therapy, in order to evaluate the value of clinical and microbiological parameters to predict treatment success.

MATERIAL AND METHODS

Clinical and microbiological data were available from 271 sites in 10 systemically healthy non-smokers with moderate-to-advanced chronic periodontal disease (24-32 sites per individual). Subgingival plaque samples were tested for the presence of Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Tannerella forsythensis and Treponema denticola using RNA probes.

RESULTS

Stepwise multiple linear regression analysis revealed a significant impact of the number of sites with visible plaque index >1 after hygienic phase on the bleeding tendency of a subject at month 6 (p<0.01). Furthermore, an association could be demonstrated between the number of residual pockets (PD>3 mm) 6 months after therapy and the number of bleeding sites and suppurating sites after hygienic phase (p=0.016). Six weeks after therapy, the mean total bacterial loads had a significant impact on the bleeding tendency of a subject at month 6 (p<0.01). Although the average numbers of sites with persisting P. gingivalis, A. actinomycetemcomitans, T. forsythensis and T. denticola seemed to be very similar 6 weeks and 6 months after therapy, large variations were noted between subjects, and therefore the microbiological status of a subject at week 6 could not predict the status at month 6.

CONCLUSIONS

The present study showed a limited potential of microbiological tests, performed after hygienic phase or shortly after non-surgical periodontal therapy, to predict the clinical outcome 6 months later, but confirmed the importance of an establishment of perfect oral hygiene before non-surgical therapy.

[Small bowel tumors -- peculiarities of diagnosis and evolution]

The authors analyze 13 cases of small bowel tumors. There are emphasized the difficulties of diagnosis, which is rarely established before the laparotomy. In the same time, clinical features are few and operations are often performed too late, in emergency, due to tumors complications (perforation, bleeding, occlusion). There are also presented new etiopathogenic hypothesis, recently mentioned in literature. Surgical treatment is followed by many post-operative complications. Five-years survival is low, under 40% of patients.

Non-covalent binding of benzaldehyde to beta-lactoglobulin: characterisation by spectrofluorimetry and electrospray ionisation mass-spectrometry

β-Lactoglobulin (β-lg), which is found in the milk of several mammal species, is the most abundant protein in bovine whey (McKenzie, 1971). The interaction properties of β-lg with a large variety of small hydrophobic ligands have been extensively studied (Sawyer et al. 1998). β-Lg belongs to the super-family of hydrophobic molecule transporters called the lipocalins, which characteristically bind hydrophobic ligands inside a central calyx (Godovac-Zimmermann, 1988; Perez et al. 1989; Brownlow et al. 1997; Wu et al. 1997; Qin et al. 1998).

At present, whey protein concentrates containing a high percentage of β-lg are commercially available in a very large quantity, but most of the processes used in milk technology involve heat-treatments that are known to affect the initial conformational state of β-lg. Such conformational changes have consequences for both the physicochemical and functional properties in food systems, including a decrease in the availability of lysine, due to Maillard reactions (Léonil et al. 1997) and a decrease in the affinity constant for binding to retinol (Laligant et al. 1991) and to flavour compounds (O'Neil & Kinsella, 1988). In the field of protein-volatile compound interactions, we have recently reported a significant enhancement of foaming properties of β-lg solutions (50 mM-NaCl, pH 6) in the presence of aroma compounds such as isoamyl acetate (Marin & Relkin, 1999), benzaldehyde (BZA; Marin & Relkin, 2000) and vanillin (Relkin & Vermersh, 2000). The observed increase in foaming properties of β-lg was postulated to be due to formation of surface active complexes between β-lg and aroma compounds.

In the present work we have investigated the interaction between a β-lg concentrate (prepared by ultra-diafiltration on an industrial scale) and BZA; particularly, evidence was sought for the presence of covalently bound monomers, dimers and lactolated monomers.

[Acute abdomen and diabetic patients--difficulties of diagnosis and therapeutical decision]

We present a retrospective study based on 50 diabetic patients with acute abdominal diseases. Usually, clinical features were not typical, without defining signs of acute abdomen, despite frequent severe anatomo-pathological forms (6 of 12 acute appendicitis were gangrenous, with generalised or localised peritonitis; 15 of 22 acute colecystitis were gangrenous). In diabetic patients, with metabolic disorders and cetoacidosis, positive diagnosis and the decision of laparotomy are difficult problems, often delated, with a negative influence on the evolutions and prognosis of these patients.

Microbial Community Composition and Ecology of an Acidic Aquatic Environment: The Tinto River, Spain

We studied the correlation between physicochemical and biological characteristics of an acidic river, the Tinto River, in Southwestern Spain. The Tinto River is an extreme environment characterized by its low pH (mean of 2.2) and high concentrations of heavy metals (Fe 2.3 g/L, Zn 0.22 g/L, Cu 0.11 g/L). These extreme conditions are the product of the metabolic activity of chemolithotrophic microorganisms, including iron- and sulfur-oxidizing bacteria, that can be found in high concentrations in its waters. The food chain in the river is very constrained and exclusively microbial. Primary productivity in the Tinto River is the sum of photosynthetic and chemolithotrophic activity. Heterotrophic bacteria and fungi are the major decomposers and protists are the major predators. A correlation analysis including the physicochemical and biological variables suggested a close relationship between the acidic pH values and abundance of both chemolithotrophic bacteria and filamentous fungi. Chemolithotrophic bacteria correlated with the heavy metals found in the river. A principal component analysis of the biotic and abiotic variables suggested that the Tinto River ecosystem can be described as a function of three main groups of variables: pH values, metal concentrations, and biological productivity.

[Evaluation of the adherence to nursing care protocols in a district]

An experience of construction and implementation of nursing care protocols and procedures for district nurses is described. A course was offered to all the district nurses, where the indications for the nursing care of some common patients' problems (pressure sores management, mobilization of the stroke patient, the management of patients in pain; the nursing care to stoma patients etc.) were presented. After having compared their work habits with the indications derived from the literature, the nurses were asked to produce protocols and procedures for the problems addressed during the course. The protocols were revised by experts and formally adopted by the responsible of the District, printed in a booklet and mailed with an official letter, to all the district nurses. After two years from the mailing, the knowledge of the nurses (44) on the areas covered by the guidelines was assessed with a multiple choice questionnaire. The level of knowledge varied from 100% of correct answers for the meatal care before catheterization, to the 23% of correct answers on how to remove the needle from a port-a-cath system. The level of knowledge was dishomogenous not only across nurses but also across subjects. In fact low level of correct answers were obtained also for frequently encountered problems, such as patients with pressure sores. The possible causes of the failure of the implementation of the guidelines are discussed.

[Communication in the patient care team about palliative situations' results of a survey at the Laennec Hospital, Paris]

The authors report results from a sample survey in a university hospital in connection with the aspects of communication in medical team about paliative situations. The questionnaire, made from a paliative care group, consults the usual practices and during crisis just as patient is dying, in a curative medical care. Hospital is not a place to die. Difficulty in survey are probably in keeping with individual and collective defences opposite to dying patient.

[Tuberculous adenopathies of the mediastinum: surgical experience in adults]

Fifty eight patients were treated for mediastinal tuberculous adenopathies in the thoracic surgery department from 1986 to 1992. Surgery was diagnostic in 49: mediastinoscopy n = 42, left anterior mediastinotomy n = 3, thoracotomy n = 3 and video assisted surgery n = 1. Surgery was in view of cure in 9: bronchial fistula despite medical treatment n = 6, recurrence under medical treatment n = 3. Mediastinal tuberculous adenopathies rarely complicate in adults. Surgical treatment is quickly effective in prolonging and complicating cases under medical treatment and also probably diminishes the risk of bronchial and pulmonary sequellaes.

Environmental airborne tremolite asbestos pollution and pleural plaques in Afghanistan

A 51-year-old man underwent pleuroscopy for radiologic pleural abnormalities. Pathologic examination of pleural and lung biopsy specimens concluded on hyalinized pleural plaques associated with mild asbestosis. Transmission electron microscopy analysis showed significant retention of tremolite asbestos fibers. The absence of any occupational exposure to asbestos and the existence of geologic deposits of tremolite in the Kabul area of Afghanistan suggest an environmental exposure during the patient's childhood spent in this region.

The evolutionary history of Drosophila buzzatii. XXIII. High content of nonsatellite repetitive DNA in D. buzzatii and in its sibling D. koepferae

The frequency and types of repetitive nonsatellite DNA of two sibling species of the repleta group of Drosophila, D. buzzatii, and D. koepferae have been determined. For each species, the analysis is based on a sample of more than 100 clones (400 kb) obtained from genomic DNA. A theoretical model has been developed to correct for the presence of a mixture of repetitive and unique DNA in these clones. After correction, a high content of repetitive DNA has been demonstrated for both species (D. buzzatii, 19-26%; D. koepferae, 27-32%). The repetitive sequences have been classified according to their hybridization pattern when used as probes against genomic DNA and by their in situ hybridization signals on polytene chromosomes. Data suggest that the main nonsatellite component of these species is simpler and more repetitive than that of D. melanogaster, pointing to a wide variability in content and class size distribution of repetitive DNA among Drosophila species.

Osteoarticular tuberculosis of the symphysis pubis presenting as a hypogastric cystic mass in a woman with primary Sjögren's syndrome

A 79-year-old woman with primary Sjögren's syndrome and immune thrombocytopenia presented with a hypogastric cystic mass. Twenty-three months previously she received a 7-month course of prednisone at moderate doses to control the thrombocytopenia. A computed tomography showed a cystic mass, destruction of the left pubis with involvement of the symphysis and erosion of the right pubis. The cystic mass was surgically removed. Epithelioid granulomata were found on pathological examination and Mycobacterium tuberculosis was grown in Löwenstein medium. This is the first reported case of osteoarticular tuberculosis with such a presentation and only the second localized to the pubis.

Sexual isolation in Drosophila. I. Theoretical models for multiple-choice experiments

Several simple models are developed to calculate expected mating frequencies in ethological isolation experiments. They take into account the effect that the peculiar sexual behavior of Drosophila species can have in multiple-choice experiments. These models depend on only three basic parameters: male competitive ability (C), female receptivity (R) and the coefficient of females acceptance (A). Two types of model can be distinguished: (1) models with discrete preferences, in which A is a measure of the percentage of females accepting a particular kind of male and (2) models with continuous preferences, in which A represents the probability of acceptance for each courtship. It is demonstrated that the information rendered by just one experiment, although effective for determining whether sexual isolation exists, it is insufficient to estimate its degree or to demonstrate that it is asymmetrical. Further developments of the models under more complex conditions as well as their implications for reinforcement and founder effect theories are discussed.

Chromosome location of a family of genes encoding different acidic ribosomal proteins in Saccharomyces cerevisiae

DNA probes from the genes encoding the acidic ribosomal proteins L44, L44' and L45, as well as from reporter genes for chromosomes IV, VII, XII and XV, have been hybridised to Southern blots of Saccharomyces cerevisiae DNA resolved by pulsed field gel electrophoresis. The protein L44' and protein L45 genes have been found to hybridise to chromosome IV, identified by the CAT1 gene probe, while the protein L44 probe hybridises with a band containing chromosomes VII and XV, identified by the ATPase 1 and HIS3 genes respectively.

[Cat-scratch disease. Comments on a clinical case]

The authors present a clinical case of cat's scratch disease, with lymphadenitis and inoculation pustule. A series of observations are made on the importance of anamnesis, histopathologic examination, elimination of other clinical entities with lymphadenopathic manifestations, for determining the diagnosis. The recent investigations are aimed at identifying the etiologic agent. The treatment of the disease is symptomatic.