Copper naphthenate treatments for engineered wood composite panels.

This paper reports on preliminary investigation of the properties of randomly oriented strandboard which had waterborne or powdered copper naphthenate incorporated into the board during manufacture. When compared to zinc borate-treated controls, the mechanical properties of strandboard were not adversely affected by treatment with either form of copper naphthenate. In general, values for mechanical properties followed the trend untreated controls > waterborne CuN = powdered CuN > ZnB. Water absorption and dimensional properties followed a similar trend. This preliminary study suggests that CuN is a viable alternative treatment for engineered wood composites.

Frequency of illness associated with epidemic hepatitis A virus infections in adults.

Hepatitis A virus infection is often described as mild or asymptomatic, particularly in children. The failure of most adults who are found to be immune to remember symptoms of an illness suggestive of hepatitis A virus supports this belief. In 1982, two large outbreaks occurred in well documented populations of military personnel. These outbreaks were each extensively studied epidemiologically and serologically. It was found that 28/29 (96.6%) hepatitis A infections recognized prior to immune serum globulin in Outbreak A and 35/46 (76.1%) infections in Outbreak A were symptomatic. Symptomatic cases failed to occur beyond eight days of immune serum globulin administration to these predominantly susceptible groups. Between 40 and 70% of patients were icteric. Apparent contrasts in symptoms associated with hepatitis A infection in adults and children suggest a basic age-dependent difference in immune response to such infection.

Swine flu vaccine and multiple sclerosis.

Using age-specific rates for multiple sclerosis (MS) based on a national survey, the number of "naturally occurring" new cases of MS among the 45 million swine flu vaccine recipients in the United States is estimated as 1,624 during the year after vaccination, or 31 cases per week. Information from available reports and publications indicates no excess over the expected frequencies. Analyses of admissions for MS before, during, and after the immunization program showed no increase to the US Army hospitals or to the Mayo Clinic. Three independent controlled clinical investigations performed on patients with MS showed no increase in the frequency of exacerbations among those receiving swine flu vaccine as compared with those receiving placebo. Epidemiologic features of MS do not implicate killed virus vaccine as an etiologic factor in onset or exacerbations of the disease. There is no indication from these analyses of any association or cause-and-effect relationship between swine flu vaccine and MS.

An efficacy trial of doxycycline chemoprophylaxis against leptospirosis.

Because leptospirosis has been an important cause of morbidity in U.S. soldiers training in the Republic of Panama, we conducted a randomized, double-blind, placebo-controlled field trial during the fall of 1982 to determine whether doxycycline was an effective chemoprophylactic agent against this infection. Doxycycline (200 mg) or placebo was administered orally on a weekly basis and at the completion of training to 940 volunteers from two U.S. Army units deployed in Panama for approximately three weeks of jungle training. Twenty cases of leptospirosis occurred in the placebo group (an attack rate of 4.2 per cent), as compared with only one case in the doxycycline group (attack rate, 0.2 per cent, P less than 0.001), yielding an efficacy of 95.0 per cent. This study demonstrated the value of doxycycline as a prophylactic drug against leptospirosis.

Ultrastructure of fusion products from soybean cell culture and sweet clover leaf protoplasts.

Protoplasts from cultured cells of soybean (Glycine max L.) and from sweet clover (Melilotus officinalis L.) mesophyll cells were fused with polyethylene glycol and subsequently cultured for six days. The resulting fusion products as well as unfused protoplasts of each parental species regenerated cell walls and divided. The fusion products were characterized by the presence of soybean leucoplasts and sweet clover chloroplasts. The chloroplasts appeared to be degenerating but other cytoplasmic organelles were typical of actively growing plant cells. The fate of individual nuclei could not be determined.

Phytostat for continuous culture and automatic sampling of plant-cell suspensions.

An apparatus for growing plant cells in suspension culture is described; it may be used for continuous or batch culture, and is equipped with a valve for automatic collection of samples. Aeration is by continuous bubbling of air into the culture through fritted glass. Normal culture-duplication times are from 30 to 35 hours.