Survey of shock-wave structures of smooth-particle granular flows

We show the effects of simulated supersonic granular flow made up of smooth particles passing over two prototypical bodies: a wedge and a disk. We describe a way of computationally identifying shock wave locations in granular flows and tabulate the shock wave locations for flow over wedges and disks. We quantify the shock structure in terms of oblique shock angle for wedge impediments and shock standoff distance for disk impediments. We vary granular flow parameters including upstream volume fraction, average upstream velocity, granular temperature, and the collision coefficient of restitution. Both wedges and disks have been used in the aerospace community as prototypical impediments to flowing air in order to investigate the fundamentally different shock structures emanating from sharp and blunt bodies, and we present these results in order to increase the understanding of the fundamental behavior of supersonic granular flow.

HLA class II genes in chronic hepatitis C virus-infection and associated immunological disorders

To investigate the factors that may confer susceptibility or protection to hepatitis C virus (HCV) infection and to HCV-associated immunological disorders, we designed two studies on 420 Sardinian transfusion-dependent thalassemia patients followed in our department in Cagliari since 1974. The first one was an epidemiological survey aimed to evaluate the prevalence of HCV infection and HCV-associated immunological disorders. In the second study, the distribution of different HLA class II genes was examined by DNA analysis in 116 HCV positive patients, 30 HCV negative patients, and 606 healthy controls. Three hundred fourteen patients became infected with HCV (74.7%) after 5.6 +/- 2.8 years of regular transfusion program. Mixed cryoglobulinemia, purpura, arthritis, proteinuria, decreased complement levels, rheumatoid factor and anti-GOR, smooth muscle antibody (SMA), anti-nuclear antibody (ANA), and liver, kidney microsome (LKM) autoantibodies were significantly more represented in HCV positive patients than in negative ones (P < .05). A significant increase of HLA class II DR2 subtype (DRB1*1601,DQB1*0502) was observed in a group of 30 HCV negative patients who despite 10.3 +/- 2.2 years in a regular blood transfusion program did not show any evidence of HCV infection (Pc < .0092). Our results represent clear evidence for a relationship between HCV infection and immune extrahepatic abnormalities. A gene(s) located in the human major histocompatibility complex (MHC) region may play an important role in conferring protection against HCV infection.

Cryoglobulinemia in transfusion-dependent thalassemia major

OBJECTIVE

The aim of this study was to determine the frequency of cryoglobulinemia and associated symptoms in transfusion-dependent thalassemia patients at high risk for HCV infection.

METHODS

A controlled epidemiological study was used to evaluate the prevalence of clinical, biochemical and immunological abnormalities in a group of 264 HCV-positive and 106 HCV-negative transfusion-dependent thalassemia patients. Haematologic and hepatic function tests were performed according to standard methods. HCV-RNA was detected by PCR analysis.

RESULTS

The significant presence of cryoglobulinemia and associated symptoms (purpura, vasculitis, arthritis, asthenia, proteinuria), serum autoantibodies (SMA, anti-GOR, ANA, LKM), low complement and rheumatoid factor were found in HCV-positive compared with HCV-negative patients.

CONCLUSIONS

This study demonstrates the role of HCV in inducing cryoglobulinemia and immunological disorders in transfusion-dependent thalassemia patients. HCV infection and associated immune abnormalities are a new clinical aspect of, and deserve particular attention due to their high frequency in, transfusion-dependent thalassemia patients.

The role of pre-core hepatitis B virus mutants on the long-term outcome of chronic hepatitis B virus hepatitis. A longitudinal study

To define the relationship between pre-core hepatitis B virus mutants and the long-term outcome of chronic hepatitis B virus infection, we monitored the type of circulating pre-core hepatitis B virus-DNA by polymerase chain reaction and sequencing in 41 selected chronic HBsAg carriers with extensive follow up. They included 12 HBeAg-positive patients with chronic hepatitis, who seroconverted to anti-HBe during follow up and 29 anti-HBe positive patients, 23 of whom had chronic hepatitis and six acute severe exacerbation occurring spontaneously (three cases) or during antitumor chemotherapy (three cases). In the presence of HBeAg, all showed prevalence of the pre-core wild type along with high levels of viral replication and elevated alanine aminotransferase. Anti-HBe seroconversion was accompanied by a dramatic reduction of hepatitis B virus replication and normalization of alanine aminotransferase in all, except one, and by the emergence of mutated strains with a pre-core stop codon (point mutation G to A at nt 1896) that replaced the wild type in seven of the 12. Of the seven who harboured the pre-core mutant, three continued to show normal alanine aminotransferase during subsequent follow up, three had mild alanine aminotransferase elevation and one had an acute short-lived reactivation after 4.4 years of normal alanine aminotransferase. The five cases who continued to show prevalence of wild type in spite of anti-HBe seroconversion all revealed persistently normal alanine aminotransferase.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatitis C virus in multiple episodes of acute hepatitis in polytransfused thalassaemic children

We investigated the course of distinct episodes of acute non-A, non-B (NANB) hepatitis in three polytransfused thalassaemic children. In each case, the first episode was associated with the appearance of serum hepatitis C virus (HCV) RNA and anti-HCV seroconversion. The second episode was accompanied by the reappearance of HCV viraemia, which in two patients was due to reinfection with a different HCV strain and in the third could be the result of either reactivation of primary infection or reinfection with a new but closely related strain. Thus HCV infection may not induce protective immunity, which has implications for vaccine development.

Markers of hepatitis C virus infection in Sardinian blood donors: relationship with alanine aminotransferase levels

Serum samples from 1,765 consecutive Sardinian blood donors, negative for hepatitis B surface antigen (HBsAg) and for antibodies to human immunodeficiency virus (HIV) (anti-HIV), were evaluated for the presence of antibodies to hepatitis C virus (anti-HCV) by second-generation ELISA. Anti-HCV was detected in 25 (1.45%) of the 1,765 donors examined. Anti-HCV was found in 15 of the 1,690 (0.9%) donors with normal alanine aminotransferase (ALT) and in 10 of the 75 (13%) donors with elevated ALT (P < 0.0001). Of the 15 anti-HCV-positive donors with normal ALT, only five (33%) were confirmed to be positive by second-generation RIBA, six (40%) were indeterminate, while four (27%) were RIBA negative. HCV RNA, as detected by polymerase chain reaction (PCR) using a set of primers from the 5'-noncoding region, was found in six of the 15 (40%) donors with normal ALT, including five RIBA positive and one indeterminant. Of the 10 anti-HCV-positive donors with elevated ALT, all were RIBA positive and eight (80%) had detectable HCV RNA. Thus, among ELISA-reactive donors, those with elevated ALT had a significantly higher probability of being positive for second-generation RIBA and HCV RNA compared to those with normal ALT levels (P = 0.028). None of the 65 donors with elevated ALT but negative for anti-HCV by ELISA had detectable serum HCV RNA, as compared to eight of 10 anti-HCV ELISA-positive donors (P < 0.0001). However, although negative for HBsAg, 12 of the 65 (18%) had serum HBV DNA by PCR.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of antibodies to hepatitis C virus in a long-term prospective study of posttransfusion hepatitis among thalassemic children: comparison between first- and second-generation assay

During an 8-year prospective study of post-transfusion hepatitis conducted at the Thalassemic Center of Cagliari (Italy), including 135 newly diagnosed thalassemic children on long-term transfusion maintenance, 83 children (61%) developed non-A, non-B hepatitis (NANBH). Resolution of NANBH was observed in 17 (20%) cases, and chronicity in 57 (69%), whereas the remaining 9 (11%) experienced one or two additional bouts of acute NANBH. Of the 83 children with NANBH, 75 (90%) showed anti-hepatitis C virus (HCV) seroconversion when tested by second-generation enzyme-linked immunosorbent assay (ELISA), whereas first-generation ELISA showed anti-HCV in only 59 (71%) cases (p = 0.003). Moreover, the newly developed assay allowed an earlier detection of anti-HCV response in most of the patients who seroconverted by both assays, reducing significantly the mean onset-seroconversion interval (5 +/- 9.4 weeks vs. 14.5 +/- 20.8 weeks, p < 0.05). It was significantly more sensitive for the identification of HCV infection, not only in resolving NANBH, but also in NANBH progressing to chronicity (79 vs. 35%, respectively, p = 0.008; and 93 vs. 79%, p = 0.028). The pattern of antibody response with first-generation assay was characterized by clearance of anti-HCV with time, in most of the patients who recovered, and by persistence of anti-HCV in the majority of those who progressed to chronicity, whereas second-generation ELISA usually showed persistence of anti-HCV over time, regardless to the outcome of the disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Polymerase chain reaction analysis for specific HTLV-1 sequences from cerebrospinal fluid and peripheral blood cells in Sardinian multiple sclerosis patients

Using polymerase chain reaction and specific primers, we found no gag and env sequences of HTLV-1 in DNA samples from peripheral blood mononuclear cells of 26 multiple sclerosis (MS) patients with relapsing-remitting, relapsing-progressive and progressive course from onset of the disease, and from 8 patients affected with other neurological diseases (OND). A Positive signal for the gag region was found in DNA samples from cerebrospinal fluid mononuclear cells (CSFMC) of 6/17 (27.3%) MS patients (either with relapsing-remitting, or relapsing-progressive and progressive course from onset of the disease), and in 2/11 (18.2%) CSFMC OND samples. Positive hybridization for the env sequence was evident in 2/11 (18.2%) CSFMC from OND and none of MS samples. The finding of positive hybridization for gag and env sequences in a few samples of CSFMC may be related to the presence in the CSF of a great number of activated cells, which could express cross-reacting sequences of endogenous retrovirus.

Development of thyroid disease in patients with primary and secondary Sjögren's syndrome

Autoimmune thyroid disease associated to Sjögren syndrome (SS) may be defined by serological and functional abnormalities. We studied the prevalence of serum anti-thyroid autoantibodies and the development of thyroid functional defects by a follow-up investigation in patients with primary (pSS) and secondary SS (sSS). In keeping with previous literature data, our findings confirmed an increased prevalence of thyroid autoimmune phenomena in the whole series of patients with SS. In addition, evidence was provided for a greater incidence of serological and functional thyroid abnormalities in pSS when compared to sSS. Follow-up study also showed that the rate of thyroid autoimmune disease development was higher in pSS than in sSS. The appearance of circulating anti-thyroid antibodies was particularly frequent in patients with preexisting antibodies against extractable nuclear antigens (anti-ENA). These data indicate the need for a careful monitoring of thyroid function in SS patients, with particular regard to those with pSS and positive anti-ENA tests.

Conductivity values of tissue culture medium from 20 degrees C to 40 degrees C

Few studies are available that relate conductivity and temperature in solutions commonly used in tissue culture media. The purpose of this paper is to provide equations relating conductivity and temperature (in the range 20 degrees C-40 degrees C) for five solutions: 0.9% saline, MEM (Minimum Essential Media), horse serum, MEM with 1% horse serum, and MEM with 10% horse serum.