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Biomedical subjects

G Halama

Publications and source records attributed to G Halama.

At least 19 recordsLinked to original sources
PubMed1998

Composite x-ray image assembly for large-field digital mammography with one- and two-dimensional positioning of a focal plane array.

To demonstrate the feasibility of a novel large-field digital mammography technique, a 1024 x 1024 pixel Loral charge-coupled device (CCD) focal plane array (FPA) was positioned in a mammographic field with one- and two-dimensional scan sequences to obtain 950 x 1800 pixel and 3600 x 3600 pixel composite images, respectively. These experiments verify that precise positioning of FPAs produced seamless composites and that the CCD mosaic concept has potential for high-resolution, large-field imaging. The proposed CCD mosaic concept resembles a checkerboard pattern with spacing left between the CCDs for the driver and readout electronics. To obtain a complete x-ray image, the mosaic must be repositioned four times, with an x-ray exposure at each position. To reduce the patient dose, a lead shield with appropriately patterned holes is placed between the x-ray source and the patient. The high-precision motorized translation stages and the fiber-coupled-scintillating-screen-CCD sensor assembly were placed in the position usually occupied by the film cassette. Because of the high mechanical precision, seamless composites were constructed from the subimages. This paper discusses the positioning, image alignment procedure, and composite image results. The paper only addresses the formation of a seamless composite image from subimages and will not consider the effects of the lead shield, multiple CCDs, or the speed of motion.

Biophysical Phenomena↗
PubMed1992

Prevalence of markers of hepatotropic viruses among drug addicts in Warsaw, Poland.

We studied 100 unselected parenteral drug abusers for infection with hepatitis C, B, A and D virus (HCV, HBV, HAV and HDV). Seventy-six percent had serological evidence of HCV infection. 12% were positive for HBsAg and at least one marker of HBV infection was present in 69%. These results were significantly higher than in a matched control population. Compared to controls, the prevalence of anti-HAV (65%) was not significantly increased in drug addicts. Of the anti-HCV-positive drug addicts, 80.3% had at least one marker of HBV infection compared to 33.3% of anti-HCV-negative cases (p less than 0.001). No such correlation was found between the prevalence of HCV or HBV infection markers and the presence of anti-HAV. Antibodies against HDV were detected in 16 (16%) of the samples from drug addicts. No significant association was found between antibodies to HCV and gender, age and duration of drug abuse. The risk of HBV infection increased significantly with years of drug abuse but was not associated with age and sex. The presence of anti-HAV was related to age only. Sixteen (16%) of the subjects were definitely positive for anti-HIV-1, but at the time of the study they were asymptomatic. No significant association was found between the presence of anti-HIV and the prevalence of serological markers of HBV, HCV, HAV and HDV infection.

Adolescent↗
PubMed1992

[Appearance of antibodies against hepatitis type A virus (HAV) in alcoholics].

In 144 alcoholics--patients of alcoholic outpatient clinic anti-HAV antibodies were studied using the commercially available ELISA test. Anti-HCV antibodies were found in 86% of the alcoholics, and this prevalence was not higher than in the control group. No differences were found in the titre of antibodies against cytomegaly and herpes virus between the subjects with and without anti-HAV antibodies which suggests the specificity f the determined anti-HAV antibodies.

Adult↗
PubMed1992

[Occurrence of antibodies against hepatitis C virus (HCV) among alcoholics].

144 consecutive alcoholics attending an outpatient clinic were tested for the prevalence of anti-HCV with commercially available ELISA test (Abbott HCV EIA). Positive sera were further tested with neutralization assay (Abbott HCV Neutralization Assay). Anti-HCV were found in 35 (24%). There was no difference in the prevalence or mean titre of anti-CMV and anti-HSV between patients with and without anti-HCV what points to the specificity of tested antibodies.

Adult↗
PubMed1991

Hepatitis C virus antibody in Poland.

To assess the epidemiology of hepatitis C virus (HCV) in Poland, anti-HCV was studied in patients with acute and chronic non-A, non-B (NANB) hepatitis, in healthy adults, and in subjects at risk. Anti-HCV prevalence was 2% in 152 blood donors, 78% in 95 parenteral drug addicts, 21% in 112 alcoholics, and 86% in 42 patients with chronic NANB hepatitis. Among 34 prospectively followed patients with acute NANB hepatitis 17 (50%) developed anti-HCV. It seems that HCV infection is responsible for the majority of NANB hepatitis in Poland and is common in parenteral drug abusers and alcoholics.

Hepacivirus↗
PubMed1991

[Cytomegalovirus hepatitis].

Among 530 consecutive patients hospitalized for acute hepatitis cytomegalovirus infection was diagnosed in 5 (0.9%). In 2 cases the infection was due to blood transfusion. The course of the disease was Got essentially different from hepatitis A, B, or non-A, non-B, however, clinical and biochemical manifestations of cholestasis were common. All biochemical abnormalities returned to normal within few weeks. In conclusion, it seems that cytomegalovirus is a rare cause of clinically overt hepatitis and its course is often cholestatic.

Acute Disease↗
PubMed1991

[Antibodies against Cytomegalovirus and Herpes simplex virus in alcoholics and drug addicts].

Anti-CMV and anti-HSV type 1 of the IgG class were tested in 123 consecutive outpatient alcoholics and 95 consecutive drug addicts admitted to a detoxification ward. The prevalence of both viral markers in these groups was not different from the prevalence found among controls, however, antibody titres were significantly higher. Only weak correlation was found between titres of anti-CMV and anti-HSV in tested subjects. The reasons responsible for high titres of anti-CMV and anti-HSV remain to be determined.

Alcoholism↗
PubMed1991

[Delta virus infection among drug addicts].

Altogether 240 unselected intravenous drug addicts were tested for the presence of infection with delta virus (HDV). Anti-delta were found in 16 (16%) out of 100 drug addicts tested in the years 1988-1989 and in only one drug addict (0.7%) out of 140 tested in the years 1985-1986. It seems that delta virus has been introduced to Warsaw drug community in the mid-eighties and has spread enormously since that time.

Hepatitis Antibodies↗
PubMed1991

[Non-A, non-B hepatitis--epidemiologic and clinical aspects].

In the years 1986-90 530 consecutive patients with acute hepatitis were hospitalized in the Department of Hepatology of the Institute of Infectious and Parasitic Diseases in Warsaw. Hepatitis A was diagnosed in 34 cases (6.4%), hepatitis B in 436 (82.3%), CMV infection in 5 (0.9%) and 55 cases (10.4%) were classified as hepatitis non-A, non-B. In 47 cases (85%) of non-A, non-B hepatitis in 8 (15%) the source of infection was unclear. In 50% of patients with parenteral exposure transaminases remained elevated for longer than 6 months, while all patients with no known exposure recovered.

Adult↗