Electron-phonon coupling and vibrational properties of size-selected linear carbon chains by resonance Raman scattering

UV resonance Raman spectroscopy of size-selected linear sp-carbon chains unveils vibrational overtones and combinations up to the fifth order. Thanks to the tunability of the synchrotron source, we excited each H-terminated polyyne (HC_nH with n = 8,10,12) to the maxima of its vibronic absorption spectrum allowing us to precisely determine the electronic and vibrational structure of the ground and excited states for the main observed vibrational mode. Selected transitions are shown to enhance specific overtone orders in the Raman spectrum in a specific way that can be explained by a simple analytical model based on Albrecht's theory of resonance Raman scattering. The determined Huang-Rhys factors indicate a strong and size-dependent electron-phonon coupling increasing with the sp-carbon chain length.

Vibrational properties of graphdiynes as 2D carbon materials beyond graphene

Two-dimensional (2D) hybrid sp–sp² carbon systems are an appealing subject for science and technology. For these materials, topology and structure significantly affect electronic and vibrational properties. We investigate here by periodic density-functional theory (DFT) calculations the Raman and IR spectra of 2D carbon crystals belonging to the family of graphdiynes (GDYs) and having different structures and topologies. By joining DFT calculations with symmetry analysis, we assign the IR and Raman modes in the spectra of all the investigated systems. On this basis, we discuss how the modulation of the Raman and IR active bands depends on the different interactions between sp and sp² domains. The symmetry-based classification allows identifying the marker bands sensitive to the different peculiar topologies. These results show the effectiveness of vibrational spectroscopy for the characterization of new nanostructures, deepening the knowledge of the subtle interactions that take place in these 2D materials.

Raman and IR spectra investigation of 2D carbon crystals belonging to the family of graphdiynes (GDYs) and having different structures is performed in this paper, focusing on how these spectra are affected by different topological features.

Carbon-atom wires: 1-D systems with tunable properties

This review provides a discussion of the current state of research on linear carbon structures and related materials based on sp-hybridization of carbon atoms (polyynes and cumulenes). We show that such systems have widely tunable properties and thus represent an intriguing and mostly unexplored field for both fundamental and applied sciences. We discuss the rich interplay between the structural, vibrational, and electronic properties focusing on recent advances and the future perspectives of carbon-atom wires and novel hybrid sp-sp(2)-carbon architectures.

[Computer terminals. Evaluation of utilization time]

The aim of the present study was to compare the duration of computer use assessed through a software package and through self-report by questionnaire. Applied in a large Public Administration the software package led altogether to a remarkable reduction in the number of workers reaching the duration of use which requires medical examination. Nevertheless, it highlighted that self-reporting of a considerable number of workers had underestimated the computer use. The consistency with Italian laws is also discussed.

Comparison of simple tests for the non-invasive diagnosis of clinically silent cirrhosis in chronic hepatitis C

BACKGROUND

Biopsy is the gold standard for assessing cirrhosis in patients with chronic hepatitis C virus infection, but it is expensive and at risk of complications. Alternative non-invasive methods have been developed but their usefulness remains uncertain.

AIM

To compare the accuracy of five non-invasive scores in detecting cirrhosis.

METHODS

We reviewed the charts and liver biopsies of 228 consecutive, treatment-naïve, hepatitis C virus-positive patients, 13.2% of whom with histological diagnosis of cirrhosis. The five alternative scores were age-platelet index, cirrhosis discriminant score, aspartate transaminases to platelet ratio index, Pohl's index, and aspartate transaminases/alanine transaminases ratio.

RESULTS

The specificities of the scores were good (87-100%), but not so their sensitivities (17-67%). Accordingly positive likelihood ratios were generally good but negative likelihood ratios were suboptimal. Combinations of the scores independently related to cirrhosis only slightly change this diagnostic accuracy. Using double cut-offs to exclude/diagnoses cirrhosis, cirrhosis discriminant score classified 21% of patients without misdiagnoses and aspartate transaminases to platelet ratio index classified 85% of case with 9% of misdiagnoses.

CONCLUSIONS

The five scores showed variable sensitivities and specificities in detecting liver cirrhosis, both individually and in combination. The use of double cut-off points may make the cirrhosis discriminant score and aspartate transaminases to platelet ratio index useful to reduce the number of patients submitted to liver biopsy.

[Hand-arm vibration syndrome and upper limb disorders associated with forestry work]

BACKGROUND

Occupational exposure to hand-transmitted vibration in forestry workers is associated with an increased risk for vascular, neurological and musculo-skeletal disorders of the upper limbs.

OBJECTIVES

To carry out a cross-sectional study of the hand-arm vibration syndrome and soft-tissue disorders of the upper limb in a group of forestry workers employed in the Forestry Service of the Province of Trento (Italy). In the forestry worker group, usage of anti-vibration chain-saws was intermittent over a typical work year (16 weeks/yr, on average).

METHODS

To investigate vascular, neurological and musculo-skeletal disorders of the upper limbs, the forestry workers (n=159) and a control group of manual workers, unexposed to hand-transmitted vibration, employed in the same Forestry Service (n=146) underwent a structured medical interview and a complete physical examination. The clinical diagnoses of vibration-induced white finger (VWF) and carpal tunnel syndrome were made according to internationally recognised consensus criteria. Occupational exposure to hand-transmitted vibration was assessed according to the recommendations of the International Standard ISO 5349-1 (2001).

RESULTS

The forestry workers showed an increased prevalence of peripheral sensory-neural disturbances (33.3%), musculo-skeletal disorders of the upper limbs (37.7%), and carpal tunnel syndrome (21.4%) compared to those observed in the control group. There was no significant difference in the prevalence ofRaynaud' sphenomenon between the forestry workers (6.3%) and the controls (4.1%). After adjustment for confounding factors (age, body mass index, tobacco and alcohol consumption), a significant association was observed between peripheral neuropathies (peripheral sensory-neural disorders, carpal tunnel syndrome) and several indices of vibration exposure such as 8-hr energy-equivalent frequency-weighted acceleration [A(8) in m/s2 r.m.s.], duration of exposure (years), and lifetime vibration dose (m2/s4 hr). An excess, although not significant, risk for VWF was observed only in the forestry workers with A(8) > or = 4 m/s2 r.m.s.. In the forestry workers, there was no significant association between VWF and sensory-neural disorders, and between VWF and carpal tunnel syndrome. This finding seems to support the hypothesis that the vascular and neurological components of the hand-arm vibration syndrome develop independently of each other. Within the forestry worker group, the variable "years of tool usage" showed the strongest association with peripheral sensory-neural symptoms, carpal tunnel syndrome, and soft-tissue disorders of the upper limbs. It is likely that in the forestry workers the variable "years of tool usage" represents an overall index of duration of exposure to several adverse ergonomic and mechanical risk factors.

CONCLUSIONS

The results of this study suggest a tendency for a decrease in the occurrence of VWF among forestry workers, and this finding seems to be associated with the use of anti-vibration chain saws, the reduction of exposure duration, and the improvement of work organization. On the other hand, the forestry workers showed an increase in the occurrence of peripheral sensory neuropathies, carpal tunnel syndrome, and upper-extremity musculo-skeletal disorders. This finding seems to support the view that there is epidemiological evidence for a positive association between exposure to a combination of risk factors (segmental vibration, forcefulness, awkward posture) and the occurrence of soft-tissue disorders of the upper limb in working populations.

Prostaglandin F2 alpha can modulate the growth and the differentiation of bovine corneal epithelial cells cultured in vitro

The effects of PGF2 alpha on the growth, morphology, morphometry and keratinization pattern of bovine corneal epithelial cells cultured in vitro were studied. The cells were grown with a basal medium or, in the presence of keratocytes and/or their products, using a keratocyte-conditioning medium. Cell growth was evaluated by MTT assay. Daily treatments with exogenous PGF2 alpha at concentrations equal to or lower than 10(-6) M induced significant increases in cell proliferation when the epithelial cells were cultured on a keratocyte feeder-layer or with the conditioning medium. No variations were observed in cultures grown with the basal medium. 10(-5) M PGF2 alpha induced a decrease in cell growth under all culturing conditions. PGF2 alpha did not affect cell morphology and modified only nuclear dimensions among the cells grown under different culturing conditions. No variations of any parameters were observed between cells cultured on feeder-layer, with conditioning or basal medium and the corresponding cultures supplemented with the autacoid. Moreover, PGF2 alpha induced only the disappearance of 43 kDa keratin in cells grown on basal medium, while the keratin pattern of epithelial cells cultured on feeder-layer or with the conditioning medium was not modified by the autacoid. From these data we can suppose that a cooperation could exist between PGF2 alpha and fibroblasts and their products for the modulation of cell growth. Finally, it was observed that the autacoid had no effect on cell morphology and morphometry, except for nuclear dimensions, despite the presence of other prostaglandins, such as PGE2.

Essential amino acids increase the growth and alkaline phosphatase activity in osteoblasts cultured in vitro

An inadequate protein intake seems to be involved in the pathogenesis of osteoporosis. Moreover, protein from animal sources appears to protect against hip fracture, while protein from vegetable sources, which present low levels of essential amino acids, has no effect. In this preliminary work, the growth, the alkaline phosphatase activity and the collagen synthesis were evaluated in osteoblast cultures obtained from calvaria of newborn Sprague-Dawley rats and incubated with lysine, threonine, methionine, triptophan and arginine. Our results have shown that the essential amino acids can modulate the growth and the differentiation of osteoblasts cultured in vitro, confirming the relationship between osteoporotic hip fracture and inadequate protein intake. The compounds have mainly enhanced cell growth and alkaline phosphatase activity, and, to a lower degree, collagen synthesis. In summary, the essential amino acids can stimulate bone formation and could represents useful agents for the prevention and therapy of osteoporosis.

Scleroderma and occupational exposure

OBJECTIVES

A case-referent study was conducted in the province of Trento, Italy, to investigate the possible association between occupational exposure and scleroderma (systemic and localized variants).

METHODS

Twenty-one cases of scleroderma were ascertained from the computerized admission files of all of the local hospitals from 1976 to 1991. For each case, two age- and gender-matched referents were selected that were discharged from the hospital on the same day as the case. The subjects were interviewed with a structured questionnaire which included items for personal, work, and medical history. Exposure to organic solvents, other selected chemicals, silica dust, and hand-arm vibration was carefully investigated.

RESULTS

A significant association was found between exposure to organic solvents (aromatic hydrocarbons) and scleroderma [odds ratio (OR) 9.28, 95% confidence interval (95% CI) 1.08-243.8]. For the men, the OR for exposure to silica was 5.20 (95% CI 0.48-74.1), whereas for the women it was 2.11 (95% CI 0.20-22.0) for exposure to other selected chemicals.

CONCLUSIONS

The results of this case-referent study are consistent with those of previous case reports on the important role of occupation in the etiology of scleroderma. In particular, our findings confirm that exposure to organic solvents and silica is associated with this rare connective tissue disease.

[Scleroderma and occupational factors: a case-control study and analysis of literature]

The scientific literature concerning occupational factors associated with scleroderma consists mostly of case report type studies. We therefore undertook a case-control study in the Province of Trento using as data source the Hospital Records System. The annual rate of scleroderma incidence in the period considered (1976-1991) was 5.8 per million in females and 1.5 per million in males. A statistically significant association was observed (OR = 9.28, p = 0.039) in the population under study for occupational exposure to solvents. Also, an excess risk was observed in male subjects exposed to silica dust, even though the simultaneous exposure to other risk factors, such as hand-arm vibrations, makes it difficult to establish the specific contribution of silica dust exposure.

Detection of preclinical hepatocellular carcinoma in patients with cirrhosis

The association between hepatocellular carcinoma (HCC) and cirrhosis provides a formidable means for prospectively studying patients who are at risk of HCC. Early diagnosis of HCC is possible not only due to knowledge of the risk factors for this tumor, but also because HCC has a very long phase of intrahepatic growth and tends to grow as a solitary mass. Early diagnosis is also possible because sensitive and relatively inexpensive diagnostic tools are available. Several prospective studies of Oriental and Western patients with cirrhosis now in progress have led to the identification of many patients with small tumors. However, in the face of this evidence that screening high-risk patients may increase the yield of subclinical small tumors, no firm conclusion has yet been reached on whether early diagnosis of HCC may also increase the number of operable patients and reduce the mortality rate for this tumor.

Hepatocellular carcinoma in Italian patients with cirrhosis

BACKGROUND AND METHODS

Patients with cirrhosis of the liver are recognized as being at risk for hepatocellular carcinoma. The magnitude of the risk, the natural history of this disease, and the possibilities for detecting potentially curable tumors in patients in the Western world are unknown. To address these questions, we examined 447 Italian patients with well-compensated cirrhosis (which was of viral origin in 62 percent of them) from 1985 through 1990, performing serum alpha-fetoprotein assays and real-time ultrasonography every 3 to 12 months.

RESULTS

Hepatocellular carcinoma was found in 30 patients (7 percent) at base line and in another 29 patients (7 percent of 417 patients free of tumor at base line) during follow-up periods averaging 33 months (range, 1 to 48). The cumulative hazard of the development of hepatocellular carcinoma during follow-up was higher among patients with persistently elevated serum alpha-fetoprotein levels (12 with tumors among 42 with such levels) than among those with fluctuating levels (11 among 82) or those with consistently normal levels (6 among 255). Only 17 patients had potentially operable tumors. The proportion of potentially operable tumors among those detected during follow-up was significantly lower than the proportion at enrollment (4 of 29 vs. 13 of 30, P = 0.027). The survival at one year of the 12 patients who underwent surgery was 67 percent, and the tumor-recurrence rate was 60 percent. Outcome was not appreciably different for the five patients who refused surgery.

CONCLUSIONS

In the West, as in Asia, patients with cirrhosis of the liver are at substantial risk for hepatocellular carcinoma, with a yearly incidence rate of 3 percent. Our screening program did not appreciably increase the rate of detection of potentially curable tumors.

Hepatic arterial embolization with microencapsulated mitomycin C for unresectable hepatocellular carcinoma in cirrhosis

From 1986 to 1988, 35 patients with a hepatoma judged either inoperable or unresectable because of coexistent cirrhosis were treated with hepatic arterial embolization of mitomycin C microcapsules. Five of these 35 patients (14.5%) could not be treated because of inability to selectively cannulate the hepatic artery and were therefore excluded from the evaluation (feasibility rate, 86%). There were 24 men and six women with a median age of 57 years (range, 47 to 79) who could be classified as Okuda I (14 pts) or Okuda II (16 pts) and Child Class A:18 and Child Class B:12 in the remaining patients. A median dose of 0.5 mg mitomycin C/kg was administered to each subject and the treatment was repeated at 5 to 6 week intervals. Seventy courses were administered to these 30 patients (median, two courses/patient; range, 1 to 4). Minor complications were frequent (63%) but always either resolved spontaneously or after appropriate medical treatment. Neither severe renal nor hepatic toxicity was observed. No specific treatment related mortality was observed. When alpha-fetoprotein levels and tumor volume were assessed to evaluate the response to treatment using established criteria for identifying a response, an objective response was found in 43% of the cases treated. The actuarial median survival was 7 months and the 1-year actuarial survival was 36% (51% for those rated as Child Class A and 0% for those identified as Child Class B, P = 0.04 and 78% rated as Okuda Types I and 0% Okuda type II, P = 0.0001). The excellent quality of life and the increased survival rate experienced after mitomycin C microcapsule embolization suggest that this treatment modality can be used successfully in patients seen in the West who have unresectable hepatoma.

Utility of ascitic fluid analysis in patients with malignancy-related ascites

One-hundred and thirty-three consecutive ascitic patients hospitalized in our Liver Unit were prospectively investigated, to define the accuracy of ascitic fluid analysis in identifying malignancy. Patients with extrahepatic cancer and peritoneal carcinomatosis were characterized by positive cytology and higher ascitic levels of fibronectin, lactic dehydrogenase, carcinoembryonic antigen, and total protein than both patients with uncomplicated cirrhosis and patients with cirrhosis and liver cancer. Ascitic cytology, fibronectin, and lactic dehydrogenase (LDH) were the most sensitive and specific markers of extrahepatic malignancy. In contrast, none of these markers was useful in identifying patients with primary liver cancer complicating cirrhosis. For them, the only alteration of the ascitic fluid was an elevated alpha-fetoprotein concentration. The sensitivity, specificity, and accuracy of ascitic alpha-fetoprotein for detecting liver cancer were 87%, 95%, and 94%, respectively. Combining cytology with the determinations of fibronectin (or LDH) and alpha-fetoprotein in ascitic fluid satisfactorily differentiated 28 of 32 cases of malignancy-related ascites, with very low incidence of false-positives (4-6%). Therefore, in view of the frequent difficulties in detecting liver cancer as a complication of cirrhosis in patients with ascites, it is advisable to determine all these three markers in the same ascitic sample.

Beta-blockade prevents recurrent gastrointestinal bleeding in well-compensated patients with alcoholic cirrhosis: a multicenter randomized controlled trial

To assess the efficacy of beta-blockers in preventing rebleeding in selected cirrhotic patients and to compare the tolerance, safety and patient compliance of a selective and a nonselective beta-blocker, 94 patients were randomly assigned to propranolol (32 patients), atenolol (32 patients) or placebo (30 patients). Randomization was made at least 15 days after the bleeding episode. Propranolol was given orally at increasing doses until the resting pulse rate was reduced by approximately 25%. Atenolol was given at a fixed dose of 100 mg per day. Patients were followed up for a mean of 357 days. Rebleeding occurred in 14 patients in the placebo group, 10 in the atenolol group and eight in the propranolol group. The incidence of rebleeding was significantly lower in patients receiving propranolol than in those on placebo (propranolol vs. placebo: p = 0.01, logrank test). Atenolol was less effective than propranolol (atenolol vs. placebo: p = 0.065, logrank test). Bleeding-free survival was better for patients on active drugs than for those on placebo (propranolol vs. placebo = p = 0.01, atenolol vs. placebo: p = 0.05, logrank test). Retrospective analysis revealed that, whatever the type of treatment, abstinence from alcohol was crucial in preventing rebleeding. We conclude that beta-blocker treatment is effective in preventing rebleeding from esophageal varices in carefully selected alcoholic cirrhotic patients who survive at least 2 weeks after acute variceal hemorrhage and stop drinking.

Beta-blockers in the secondary prevention of gastrointestinal haemorrhage in well-compensated cirrhotics. A multicentre randomised controlled study

To assess the efficacy of beta-blockers in the prevention of rebleeding in selected cirrhotics and to compare the tolerability, safety of, and patient compliance with, a selective and a non-selective beta-blocker, 94 patients were randomly assigned to propranolol (32), atenolol (32), or placebo (30). Randomisation was made at least 15 days after the bleeding episode. Propranolol was given orally in increasing doses until the resting pulse rate was reduced by approximately 25%. Atenolol was given at a fixed dose of 100 mg/day. Patients were followed up for a mean of 357 days. Rebleeding occurred in 14 patients in the placebo group, 10 in the atenolol group and 8 in the propranolol group. The incidence of rebleeding was significantly lower in patients receiving propranolol than in those on placebo (PR vs PL: p less than 0.01, log-rank test). Atenolol was less effective than propranolol (AT vs PL: p = 0.065, log-rank test) but bleeding-free survival was improved for patients on active drugs compared with those patients on placebo (PR vs PL: p = 0.01; AT vs PL: p = 0.05, log-rank test). Retrospective analysis revealed that, whatever the type of treatment, abstinence from alcohol was crucial in preventing rebleeding. It was concluded that beta-blocker treatment is effective in preventing rebleeding from oesophageal varices in carefully selected alcoholic cirrhotics who survive at least 2 weeks after acute variceal haemorrhage and who cease drinking.

Intrahepatic doxorubicin in unresectable hepatocellular carcinoma. The unfavorable role of cirrhosis

To investigate the relationship between the presence of cirrhosis and the antitumor effects of locoregional chemotherapy with doxorubicin, 16 patients with nonresectable hepatocellular carcinoma (HCC) and satisfactory baseline clinical conditions (Child class A or B, Karnofsky index greater than 70%) were studied. Eight patients had post-necrotic cirrhosis, five had serum HBsAg. The dose of doxorubicin was 0.3 mg/kg body weight/day, given by continuous intracoeliac infusion for 8 consecutive days. Eight patients (six with cirrhosis) died prematurely after the first course of chemotherapy. Six (2 with cirrhosis) responded to therapy; they survived 3-33 months (median: 10). In these patients, the type and severity of drug-related side effects were comparable to those reported for patients treated by intravenous chemotherapy. The implication that in many patients with cirrhosis intrahepatic chemotherapy with doxorubicin may hasten death, lessens our interest in its use for nonresectable HCC. In fact, in Italy these cancers frequently occur in association with cirrhosis.

Case-control study of hepatitis B virus infection in chronic liver disease and hepatocellular carcinoma

The prevalence of serum hepatitis B virus markers was studied in three groups of age- and sex-matched patients: a. 31 patients with liver cirrhosis and hepatocellular carcinoma (c-HCC); b. 31 patients with chronic liver disease (CLD) and c. 62 hospitalized control subjects. The overall exposure rate to the hepatitis B virus was 90% in c-HCC, 80% in CLD and 58% in control subjects. The prevalence of hepatitis B surface antigen (HBsAg) was 29%, 13% and 1.6% in the three groups, respectively. The prevalence of hepatitis B surface antibody was significantly lower in c-HCC (9.6%) than CLD (42%) and control subjects (40%). The serological evidence of continuous viral replication (HBsAg positivity or isolated high titre hepatitis B core antibody positivity) was more common in c-HCC (39%) than CLD (12%) and control subjects (1.6%). The prevalence and patterns of aggregation of serum hepatitis B virus markers were similar in the 31 patients with c-HCC and in 11 patients with HCC without concomitant liver cirrhosis (n-HCC). In conclusion, the overall exposure rate to the hepatitis B virus is similar in c-HCC and CLD. However, serological evidence of continuous viral replication is more common in the former group. A defective clearance of the hepatitis B virus in hepatocellular carcinoma is a possible explanation of the phenomenon. The strength of the association between hepatitis B virus infection and hepatocellular carcinoma appears to be similar in c-HCC and n-HCC.

Alpha 1-antitrypsin in patients with hepatocellular carcinoma and chronic active hepatitis

Forty-seven Italian patients suffering from hepatocellular carcinoma (HCC) and 58 patients with chronic active hepatitis (CAH) were screened for alpha 1-antitrypsin (alpha 1 AT) levels and types and compared with a previously screened healthy Italian population. Serum alpha 1 AT concentrations were significantly raised among the HCC patients compared to the controls, whereas the CAH group showed no differences. The incidence of non-M phenotypes (MS, MZ and S) is significantly higher in patients with HCC than in the CAH group and the controls. The mean age of HCC patients with a non-M phenotype is significantly lower than the mean age of HCC patients with an M phenotype.