Clostridium botulinum in the lakes and waterways of London

Mud samples collected during 1974 from a large proportion of the lakes and waterways of London were examined for Clostridium botulinum. Of 69 such sites, 50 (72.5%) contained at least one type of the organism. Of the 50 positive sites, 31, 12, 1 and 10 contained, respectively, types B, C, D and E. Most of the demonstrations of type B required trypsinization of culture filtrates. An examination of 7 lakes in Edinburgh, made for the purpose of comparison, showed that 4 contained type B and one type C. An analysis of the results gave quantitative information on the value of (1) resampling apparently negative lakes, (2) the use of both heated and unheated culture inocula, and (3) trypsinization of culture filtrates.

Startle reaction to air-bag restraints

Air bags in vehicles constitute a means of passive restraint for individuals involved in auto accidents. There is fear, however, that the inadvertent nonaccident-connected deployment of one of these air bags might substantially interfere with the handling of a vehicle in which such deployment occurred. We have found that while physiologic and physical evidence of startle accompanies such unexpected deployment, good control of the vehicle continues to be exercised by the test subjects under the conditions of our experimental protocol.

Contagious bovine pleuropneumonia: mouse-protective antibody in the sera of infected and vaccinated cattle

Cattle produced humoral mouse-protective antibody (MPA) to Mycoplasma mycoides var mycoides as a result of natural infection, hyperimmunisation, vaccination with well-known strains of living vaccines or vaccination with killed cultures. Bovine MPA was distinct from complement-fixing and precipitating antibodies and was frequently detected in their absence, particularly in the sera of vaccinated--as opposed to naturally infected--cattle. In view of its defensive role in artificially-infected mice, it seems likely that such antibody plays a part in resistance to the disease in cattle. High levels of MPA followed inoculation of cattle with killed concentrated culture containing adjuvant; this finding merits further investigation, as it may lead to improved methods of vaccination.

Oligo(A) not coded by DNA generating 3'-terminal heterogeneity in a lambda phage RNA

An RNA species from Escherichia coli infected with phage lambda was purified by hybridization to lambda 1-strand DNA and shown to have variable length. This variability was due to a variable number of adenylate residues attached to the 3' end of the molecule. Pancreatic RNase treatment of the RNA-DNA hybrid removed the 3'-terminal adenylate residues, generating a homogeneous RNA molecule terminating with -Up. The results indicate the presence of adenylate residues not coded by the DNA template at the terminus of this transcript from intact cells.

A somatomedin assay using normal rabbit cartilage in clinical studies

Somatomedin (SM) is a growth hormone (GH) dependent biological growth factor in serum. A SM assay, using mechanically sliced discs from young normal rabbit costal cartilage was developed and evaluated. This assay is as sensitive and precise, while much less laborious and costly, than the hypophysectomized rat cartilage SM assay. The elevated serum SM levels in patients with acromegaly returned to normal in two patients who were cured, and remained elevated in four incompletely treated patients. The low serum SM levels in five GH deficient patients were increased to normal after treatment with human GH. SM levels were normal in 10 patients with normal GH levels and short stature due to various causes. SM levels in serum were very low in patients with chronic renal insufficiency; the mean SM level increased significantly after renal transplantation, however, it increased only minimally after hemodialysis. SM levels were subnormal in 14 patients with sever chronic liver disease. One patient with severe acute liver disease had low serum SM levels which increased after clinical recovery. These results further suggest that the liver produces SM, while the relationship of the kidney and SM is not clear.

Visualization of the posterolateral elements of the upper cervical vertebrae in the anteroposterior projection

A radiographic view in the anteroposterior projection through the open mouth for visualization of the laminae and articular processes of the upper cervical vertebrae is described. This view is adaptable to acutely injured patients.

Inhibitory action of oestrogen on calcium-induced mitosis in rat bone marrow and thymus

In the male rat injections of CaCl-2 and MgCl-2 stimulated mitosis in bone marrow and thymus tissue. The magnesium salt was also mitogenic in the normal female, but calcium only exerted its mitogenic effect after ovariectomy. Oestradiol, but not progesterone replacement therpy abolished calcium-induced mitosis in the ovariectomized rat. The inability of calcium to stimulate cell division was also apparent in the thyroparathyroidectomized female rat, suggesting the oestradiol blockage did not operate via some indirect action on the calcium homeostatic hormones calcitonin or parathyroid hormone. When thymic lymphocytes derived from male or female rats were isolated and maintained in suspension, increased calcium or magnesium concentrations in the culture medium stimulated the entry of cells into mitosis. Addition of oestradiol to the culture medium abolished the mitogenic effect of increased calcium levels, but had no effect on magnesium-induced proliferation. These experiments suggested that oestradiol might act at the cell surface to prevent the influx of calcium but not magnesium ions into the interior of the cell and thus to block the sequence of biochemical events which led to the initiation of DNA synthesis and culminate in mitosis.

The virulence of vaccine strains of Mycoplasma mycoides var. mycoides recovered from inoculated cattle

The T1 and KH3J attenuated strains of M mycoides, well-known in Africa for immunisation against contagious bovine pleuropneumonia, were recovered from the lymph nodes of cattle at intervals up to three months after vaccination. Virulence titrations in mice indicated that the organisms recovered from cattle were of no greater virulence than the strains used for inoculation. There was, therefore, no suggestion that the use of attenuated vaccines in the field might be associated with reversion to virulence after inoculation.

Human volunteer and anthropomorphic dummy tests of driver air cushion system

The dynamic impact tests at Southwest Research Institute for the first time exposed human volunteers to production-like driver air cushion system depolyments at impact levels equivalent to a 30 mph barrier crash (48 kph). No significant injury was produced. At no time was it necessary for the secondary restraint systems to be utilized and the entire program schedule was carried out as planned. All tests were conducted under the most safe and controlled conditions possible, and typify only what the air cushions might accomplish in direct, head-on impacts up to 30 mph (48 kph). In comparing the test results, the anthropomorphic dummies' response to impact was conservative compared to the human volunteers. These and other human volunteer tests were run to help understand what might be expected in real world driving conditions. To further understand the value of this new safety system, 1000 1973 Chevrolets were built and places in a high mileage fleet across the couhtry. They now have accumulated 41 millions miles of experience and have had 15 accidents of sufficient severity that the air cushion depolyed. This fleet was followed with 1974 vehicles with air cushions sold to the general public as an option. These cars, combined with the test fleet, have accumulated approximately 60 million miles and have a total of 25 depolyments with 34 occupants in the front seat. There has been one fatality in accidents involving these vehicles, a seven week old baby boy. The child was not restrained in any protective carrier. All other injuries have been classified AIS-1 except for three AIS-2. Facial injuries have been very minimal and there have been no known hearing impairments as a result of these accident situations. To date, the results have been encouraging but caution must be taken in their interpretation. The population of drivers is not to be considered normal. The 60 million miles may appear to be a large number, but only represents 25 minutes of driving time of the total U.S. car population in 1 year.

Construction of phi80 dhis carrying Salmonella typhimurium histidine operon mutations

Starting with a previously isolated F'his episome and phi80 dhis imm(lambda) cI857 transducing phage, we have constructed recombinant elements bearing previously isolated his mutations from Salmonella typhimurium. These phages were constructed as sources of deoxyribonucleic acid for in vitro biochemical experiments on gene regulation. The manipulation of genes between S. typhimurium and Escherichia coli described here may be useful in studying other S. typhimurium operons.

Effect of sub-lethal treatment with formalin on the germination of Aspergillus fumigatus spores

Sub-lethal exposure of Aspergillus fumigatus spore suspensions to formalin resulted in prolongation by 1-22 days of the period of less than one day normally needed by spores to produce visible growth in Sabouraud's liquid medium at 37 degrees C.; the degree of delay depended on the concentration of formalin and the duration of exposure, and was due to an increase in the germination-time of spores. The formalin concentration could be adjusted so as to affect the germination-time of almost all spores in a suspension without reducing viability. The effect on germination was not abolished by thorough washing or treatment with sodium sulphite. The spores of four different strains of A. fumigatus and of cultures aged 3 to 14 days reacted similarly to formalin treatment. Although of greatly reduced virulence for mice, affected viable spores were still capable of producing infection and death following intravenous inoculation, provided they were not eliminated by the host before germination occurred.

Experimental aspergillosis in mice: aspects of resistance

Intravenous inoculation of Aspergillus fumigatus spores was used to study experimentally induced and natural resistance. Slight resistance resulted in increased survival time and higher resistance produced in addition a decreased infection rate.Sublethal doses of living spores gave significant protection against challenge 3 weeks later, but large doses of heat-killed spores had no demonstrable effect.Mice from one source showed a single, dramatic decrease in dose response to a deep-frozen strain of the organism over a period of 34 months. The dose response initially resembled that described by Scholer (1959) in which one million spores killed the majority of mice. The change was almost certainly due to an increase in resistance of the mice due to environmental factors, and the resistance was probably also effective against other strains of the organism. Although not proved, it seemed likely that the resistance was due to increased natural contact with A. fumigatus or related fungi. Possibly for a similar reason, mice of the same stock bred on different premises differed in their susceptibility to infection. The results indicated that environmental resistance-producing factors may have been operating simultaneously on a number of premises housing laboratory animals in south-east England. These findings may have significance in relation to the occurrence of natural aspergillosis of mammals and birds.Of five A. fumigatus strains, four were of closely similar virulence; the fifth strain grew more slowly in vitro and was somewhat less virulent. Isolates from mice which died sporadically after small doses of spores were of no greater virulence than the inoculated strain. Although the susceptibility of mice aged 3 weeks was not uniform under all conditions, such animals were less resistant than young adult mice. Mice from six different sources showed only slight differences in susceptibility between each other, or from mice known to have developed a natural resistance.

Tetraploid origin of the karyotype of catostomid fishes

Catostomid fishes appear to have 2n(-->4n?) approximately 100 chromosomes. The Cyprinidae, from which catostomids probably diverged before the Eocene, usually have 2n = 48 or 50 chromosomes. Preliminary cytophotometric measurements indicate an approximate doubling of DNA content of cells among catostomids.