The multiplication of an influenza C virus in an established line of canine kidney (MDCK) cells

JJ/50 and four other strains of influenza C virus grew in an established line of canine kidney (MDCK) cells. Multicycle virus growth was markedly enhanced by the addition of trypsin to the culture medium and these viruses could be passaged serially in this system. The addition of appropriate concentrations of trypsin to the agar overlay medium enabled plaquing of influenza C/JJ/50 virus. Titration by plaque assay on MDCK cells was more sensitive than that by intra-amniotic inoculation of fertile hens' eggs.

Isolation of a new avian paramyxovirus from budgerigar (Melopsittacus undulatus)

In 1974 an epizootic occurred among budgerigar flocks in Kunitachi, Tokyo, and a causative agent which possessed haemagglutinating, neuraminidase, and haemolytic activities was isolated from the lung of a dead budgerigar. This agent was 100 to 300 nm in diamter and pleomorphic. The width of the ribonucleo-protein was estimated to be about 20 nm. These results indicated that the virus, designated Kunitachi virus, was a member of the paramyxovirus group. The virus contained in the amniotic fluid from infected embryonated hen's eggs, however, at times displayed no haemagglutinating activity with different erythrocytes and complete haemagglutination could only be detected in purified preparations. The Kunitachi viruses including three strains recently isolated from the same host were found to be serologically distinct from the known paramyxovirus strains and appeared to constitute a new subtype of avian paramyxovirus.

Serological and virological investigations fo orthomyxovirus in birds in South-East Asian area

We have previously reported that some species of migrating ducks (pintail, mallard, widgeon and falcated teal) possess in their sera antibodies against H antigens of human or avian influenza viruses. Such findings have also been reported from other workers, and the appearance of new types of influenza viruses accompanied by outbreaks of new influenza pandemics, or circulation of influenza virus antigens in animals, birds and humans have been discussed on the basis of such findings. Recently a number of orthomyxoviruses have been isolated from wild birds such as myna, banded parakeets, etc. imported from India and some areas of South-East Asia. Some of them have H antigens not recognized previously, and some are found to have more or less common reactions with human H3 antigen, and consequently antigens Hav 7 and Heq 2, which are known to show cross-reaction with H3. The significance of such a fact in connection with the appearance of a new influenza pandemic is discussed.

Evaluation of a serologic test for gonorrhea in a low-risk female population

This is a report of an evaluation of a new serologic test for gonorrhea--the Gonosticon Dri-Dot Test--as compared to the standard Thayer-Martin culturing technics in a low-risk female population. The Gonosticon Dri-Dot Test detected only 50% of the gonorrhea cases discovered by the conventional culture method. Furthermore, the serologic technic accounted for 17% false-positives, indicating that a reactive Gonosticon test is not necessarily consistent with active gonococcal infection. The efficacy of the Thayer-Martin culture plate diagnostic procedure for uncomplicated gonorrhea in women was reaffirmed by this study.

Absence of neuraminidase from influenza C virus

Influenza C viruses did not possess neuraminidase activity when examined using either fetuin or sialyllactose as substrate. Purified preparations of influenza C virus inhibited hemagglutination by NWS hemagglutinin. The hemagglutination inhibiting activity was abolished by treatment of influenza C virus with neuraminidase. These findings indicated the absence of neuraminidase activity on influenza C virus particles.

The physiological responses to walking uphill under hot environment

A series of human experiments on walking uphill under radiant heat in addition to hot environment were carried out and the safety conditions for walking uphill from the standpoint of physiological response were determined. Experiments were carried out on three healthy adult males aged 21 years, walking uphill on a motor-driven treadmill with the aim of walking at a speed of 45 m/min, 55 m/min and 65 m/min and with a slope gradient of 0 degrees, 5 degrees and 10 degrees. The load weight used was 30, 40 and 50 percent of the body weight for each combination of speed, gradient and load weight. The subjects were exposed to a radiant heat of 1.3 cal/cm2.min, using 12 exsiccating infrared lamps, with a room temperature of 33 degrees C, a relative humidity of 60% and an airflow of 0.7 m/sec. The following results were obtained by estimating the physiological response (heart rate, respiration rate, rectal temperature and RMR (relative metabolic rate)) to different degrees of walking conditions during the 10-minute exercise: 1) The work intensity (RMR) of uphill walking with a certain load weight under hot environment can be changed by varying the walking speed and the load weight according to the slope gradient. 2) As there exists a gap between RMR 5 and 6 in parallel with the other physiological responses, it is preferable to keep the walking condition under RMR 6, as viewed from the change of the other walking conditions. 3) The heart rate as an indicator of the work load must be kept below 130 beats/min for a safe uphill walking of under RMR 6.