Detection and identification of human influenza viruses by the polymerase chain reaction

A series of oligonucleotide primers are described which hybridize to conserved regions of influenza virus cDNA and prime DNA synthesis in Taq polymerase catalyzed amplification reactions (PCR). Primers were designed to hybridize as nested pairs and, following a two-step amplification, produce uniquely sized DNA fragments diagnostic for viral type and subtype. Influenza A and B matrix-protein genes and the influenza C haemagglutinin gene were targets for the type-specific primers. Subtype-specific primers targeted conserved sequences within the three haemagglutinin or two neuraminidase subtypes of different human influenza isolates. The utility of this method was demonstrated using computer search methods and by accurately amplifying DNA from a variety of influenza A, B, and C strains. Type-specific primer sets showed a broad type specificity and amplified DNA from viral strains of unknown sequence. Restriction mapping and DNA sequencing showed that fragments amplified in this manner derived from the input template, confirming the accuracy of the method and demonstrating how PCR can be used to quickly derive sufficient sequence information for analysis of viral relatedness. Subtyping primers were able to distinguish accurately between the three haemagglutinin (H1, H2, H3) and two neuraminidase (N1, N2) alleles of human influenza A isolates. Again DNA was amplified from viruses of unknown sequence confirming that most of these primer sets may prove useful as broad range subtyping reagents. In order to simplify the work associated with analysis of many samples, we have also devised a rapid method for the isolation of viral RNA and synthesis of cDNA. Using this 'mini-prep' technique, it is possible to detect, amplify, and identify picogram quantities of influenza virus in a single day, confirming that PCR provides a useful alternative to existing methods of influenza detection.

Replantation of severed fingers: two unique cases

Two cases of amputated digits are reported. One involved a period of ischemia at freezing temperatures, and the other at unusually high temperatures. Both fingers survived upon replantation. The implications of extreme temperature upon ischemic tissues are discussed.

Allele loss on chromosome 16 associated with progression of human hepatocellular carcinoma

Loss of heterozygosity on chromosome 16 is a common genetic alteration in human hepatocellular carcinoma (HCC). To clarify the pathogenetic significance of allele loss on chromosome 16, we performed restriction fragment length polymorphism analysis of 70 surgically resected tumors by using 15 polymorphic DNA markers for chromosome 16. Loss of heterozygosity on chromosome 16 was detected in 36 (52%) of 69 informative cases, and the common region of allele loss in these 36 tumors was located between the HP locus (16q22.1) and the CTRB locus (16q22.3-q23.2). These losses occurred more frequently in HCCs of poor differentiation, of larger size, and with metastasis, whereas they were not detected in HCC at the earliest stage. In addition, these losses were not associated with presence or absence of hepatitis B virus DNA integration or hepatitis C virus infection. These results show that loss of heterozygosity on chromosome 16 is a late event occurring after hepatocarcinogenesis and strongly suggest that this phenomenon is involved in enhancement of tumor aggressiveness during progression of HCC.

Frequent loss of heterozygosity on chromosomes 16 and 4 in human hepatocellular carcinoma

By restriction fragment length polymorphism analysis, we examined loss of heterozygosity at 34 loci on 23 chromosomes in 35 surgically resected human hepatocellular carcinomas. Allele losses at the HP locus on chromosome 16q22 and at the MT2P1 locus on chromosome 4p11-q21 were detected in 57% (8/14) and 50% (8/16) of cases, respectively. Loss of heterozygosity on chromosomes 16q and 4 occurred simultaneously in 4 of 7 informative cases for both loci, and seemed to be important in the development of human hepatocellular carcinoma irrespective of the presence of hepatitis B virus infection. In contrast, the incidence of allele loss was low at the other loci, e.g., chromosome 1p, 3p, 11p, 13q or 17p, where one allele is frequently lost in other cancers.

Effects of traces of rare earth elements on the protozoan Blepherisma and on mice

The growth of the protozoan Blepherisma is stimulated by Lanthanum (La) at concentrations as low as 0.32 ppm. In mice Yttrium (Y) and Ytterbium (Yb) are absorbed, accumulated, and metabolized. Both rare earth elements (RE) exhibit a high affinity for teeth and bones, accumulation occurs and metabolism is slow. In the livers of RE-exposed mice, concentrations are variable. The liver is apparently capable of absorbing and discharging RE in a manner depending on metabolic activity. The main route of discharge for ingested REs is the alimentary canal. Exposure of pregnant mice to RE leads to rapid placental transfer of RE; 14.1% of the total amount of RE administered was detected in newborn mice. Young, developing organisms appear to be especially susceptible to RE accumulation.

The study of byssinosis in China: a comprehensive report

Cross-sectional studies were conducted during 1981-1983 among 861 textile workers in 3 cotton mills and 822 controls in 2 silk factories. Questionnaire and lung function tests were taken and inhalable dust concentrations were measured. Prevalence of byssinosis was 5.6%. Average dust concentrations were highest in carding rooms, 1.47-1.99 mg/m3. The correlations (r) between prevalence of byssinosis and dust concentrations was 0.64 (p less than 0.05). The prevalence of chronic bronchitis was 14.4% in cotton workers and 5.1% in controls (p less than 0.05). Acute FEV1 percent decrement (greater than 5%) was higher among cotton workers (32.1%) compared to controls (14.5%) (p less than 0.001). In one cotton blanket factory, the prevalence of byssinosis and chronic bronchitis was higher among workers in the high-dust work areas. Long-term effect studies included pulmonary function test among 173 cotton workers and 373 controls, retired 1-10 years, using the flow volume curve (FVC); chest X-rays of 140 pairs of cotton workers and controls with working tenures over 20 years; and examination of lobectomy specimens of 8 textile workers matched with 16 controls. In male cotton workers, only smokers had a prominent decrement of lung function indices, except FVC. For non-smoking females, there was no difference between the two groups. Additive effects were seen between smoking and dust exposure. According to the International Labor Organization (ILO) Pneumoconiosis Classification, the prevalence of abnormality (profusion greater than 1/0) was 4.3% and 8.7% in non-smoking controls and cotton workers. The interstitial changes on X-ray due to smoking would be much heavier. Additive effects also existed between smoking and dust exposures. No significant changes attributable to dust exposure were seen on pathological section of lobectomy specimens.

Radiographic findings in cotton textile workers and the relationship to cigarette smoking

A group of 140 cotton textile workers from Shanghai, Shandong, Guangxi, and Beijing have had their chest radiographs taken using similar requirements. Most had come from the preparatory departments of cotton mills and had a history of exposure to cotton dust for at least 20 years. As controls, 140 healthy individuals with no dust exposure were matched with respect to sex, age, and smoking history. All the radiographs were read according to the ILO International Pneumoconiosis Classification, and the manifestations belonging to categories 0/0 and 0/1 were grouped as "normal," whereas categories 1/0, 1/1, and 1/2 and above as "abnormal." There was no significant difference in X-ray abnormalities between cotton textile workers and controls (P greater than 0.05). But when the data on the cotton textile workers and controls were combined, an appreciable difference in the incidence of radiographic abnormalities was found between smokers and non-smokers (P less than 0.001). Cotton dust exposure may induce nonspecific interstitial pulmonary changes, but these changes were exaggerated by cigarette smoking. These two factors appeared to have an additive effect on the pulmonary X-ray findings.