Maclyn McCarty

Unsuspected renal artery stenosis in peripheral vascular disease.

young children. Ergonomtcs 1984;27:147. 12 Yeaton WH, Bailey JS. Teaching pedestrian safety skills to young children; an analysis and one year follow up. 7 Appl Behav Anal 1978;11:315-29. 13 Limbourg Mt, Gerber D. A parent training programme for the road. Safety education of preschool child. Accid Anal Prevent 1981;13:255-67. 14 Fortenberry JC, Brown DB. Problem identification, implementation and evaluation of a pedestrian safety programme. Accid Anal Prev 1982;14: 315-22. 15 Padgett SS, Waller PF. The evaluation of the North Carolina K-9 traffic safety curriculum: methodology, findings and recommendations. Chapel Hill, North Carolina: University of North Carolina Highway Safety Research Centre, 1975. 16 Sandels S. Young children and traffic. BrJ Ed Psychol 1970;40:111-5. 17 Gufstafsson LH. Children and traffic: some methodological aspects. Pediatrician 1979;8:181-7. 18 Hoffman ER, Payne A, Prescott S. Childrens estimate of vehicle approach times. Hum Factors 1980;22:235-40. 19 Martin GL, Heimstra NW. The perception of hazard by young children. Journal ofSafety Research 1973;5:238-46. 20 Salvatore S. The ability of elementary and secondary school children to sense oncoming car velocity. Journal ofSafety Research 1974;6:118-25. 21 Sadler J. Children and road safety: a survey amongst mothers. HMSO: London, 1972. 22 Husband P, Hinton PE. Families of children with repeated accidents. Arch Dis Child 1972;47:3%-400. 23 Wadsworth J, Burnell J, Taylor B, Bulter N. Family type and accidents in preschool children. J Epidemiol Community Health 1983;37: 100-4. 24 Brown GW, Davidson S. Social class, psychiatric disorder of mother, and accidents to children. Lancet 1978;i:378-80. 25 Backett EM, Johnston AM. Social patterns of road accidents to children: some characteristics of vulnerable families. BMI7 1959;i:409-13. 26 Organisation for Economic Cooperation and Development: Traffic safetv of children. Paris: OECD, 1983. 27 Dorsch MM, Woodward AJ, Somers RL. Accid Anal Prev 1987;19:183-90. 28 Williams A, Wells J. Evaluation of the Rhode Island child restraint law. Amj Public Health 1981;71:742-3. 29 Snyder MB. Regulations for pedestrian and cycle safety: why, who, what and how to regulate. In: Proceedings of the Metropolitan Association of Urban Designers and Environmental Planners. New York: American Societs of Civil Engineers, 1984:553-64. 30 Friends of the Earth. The case for safe routes to school: a briefing by Fnrends of the Earth Road Safety Alert. London: Friends of the Earth, 1986. 31 Royal Dutch Touring Club. Woonerf. The Hague: Royal Dutch Touring Club, 1980. 32 Esbeiisen SB. An international inventory and comparatitve study oJflegislation and guidelines for childrens play spaces in the residential environment. Ottawa: Canada Mortgage and Housing Corporation, 1979. 33 Playboard. Play and playgrounds in Rotterdam-a research approach. Birmingham: Association for Childrens Play and Recreation Ltd, 1985. 34 Chilton T. Childrens play in Newcastle upon 7yne. Birmingham: Association for Childrens Play and the National Playing Fields Association, 1985. 35 Moore RC. Childhoods domain: play and place in child development. London: Croom Helm, 1986.

Small intestinal submucosa : utilization for repair of rodent abdominal wall defects

Prosthetic graft material is often used for the repair of abdominal wall defects that result from trauma, infection, neoplastic, or congenital deformities. A new material, porcine small intestinal submucosa, has been successfully used as an arterial and venous graft material in both canine and primate animal models with graft patency and infection rates equal to autologous vein. On the basis of these studies, small intestinal submucosa was used as a graft material for the repair of a 2 x 2-cm full-thickness defect of the muscle and fascia in the rodent abdominal wall (N = 11). Two animals were euthanized at 1 week, 2 weeks, 4 weeks, 2 months, and 3 months. At the time of euthanization, no abdominal hernias were noted and only minimal intra-abdominal adhesions were observed. One animal died on postoperative day 5 as a result of a wound dehiscence. Histological analysis of the excised abdominal wall hernia repairs revealed moderate initial inflammation but with incorporation of small intestinal submucosa with minimal inflammation at 2 months. No evidence of graft-versus-host rejection was noted with hematoxylin and eosin stains and light microscopy. Porcine small intestinal submucosa merits further study as a graft material for abdominal wall replacement.

Environmental perturbations on foreign atoms and molecules in solid argon, krypton and xenon

Perturbations which are responsible for the shifts of electronic and vibrational spectra of species trapped in a solid are considered in terms of the intermolecular potential which describes interactions between these species and neighbouring atoms. It is shown that in certain instances Londons theory can give an adequate approximation to the dispersion energy between an electronically excited species and a rare gas atom. The experimental shifts in the electronic absorption spectra of Hg, NH and C2 at lattice sites in rare gas crystals at 4·2°k are explained quantitatively on the basis of a Lennard-Jones (6-12) or (6-8-12) potential between the trapped species and the rare gas atoms. The theory does not adequately explain the shifts in those cases where strong angular dependent forces differing appreciably in the two electronic states are present, data on trapped NH2 free radicals being presented as a case in point. The interaction of sodium atoms with argon at 4·2°k is very complex, the data being consi...

Why have group A streptococci remained susceptible to penicillin? Report on a symposium

In spite of 50 years of extensive use of penicillin, group A streptococci remain exquisitely susceptible to this antibiotic. This observation that continuing susceptibility has occurred despite the development of resistance to other antimicrobial agents prompted a day-long meeting at Rockefeller University (New York) in October 1996. Among the most likely explanations for this remarkable state of continued susceptibility to penicillin are that beta-lactamase may not be expressed or may be toxic to the organism and/or that low-affinity penicillin-binding proteins either are not expressed or render organisms nonviable. Other potential explanations are that circumstances favorable for the development of resistance have not yet occurred and/or that there are inefficient mechanisms for or barriers to genetic transfer. Recommended future actions include (1) additional laboratory investigations of gene transfer, penicillin-binding proteins, virulence factors, and homeologous recombination and mismatch repair; (2) increased surveillance for the development of penicillin resistance; (3) application of bioinformatics to analyze streptococcal genome sequences; and (4) development of vaccines and novel antimicrobial agents. Thus far the susceptibility of group A streptococci to penicillin has not been a major clinical or epidemiological problem. A similar observation, however, could have been made decades ago about Streptococcus pneumoniae. It is therefore vital for the scientific community to closely examine why penicillin has remained uniformly highly active against group A streptococci in order to maintain this desirable state.

Historical Perspective on C‐Reactive Protein

The history of the plasma protein response to tissue injury appropriately begins with a consideration of C-reactive protein, since it was the discovery of this substance that focused attention on what was shortly thereafter termed the acute phase response and which initiated the broader concerns with the problem that comprise the field today. It is almost impossible to derive a very dramatic story of the discovery of C-reactive protein from a review of the published papers on the subject. These have all the qualities of dry protocol and impersonality that are in the best tradition of our scientific literature, so that the papers fail to tell one much about why things were done and how they came about. A second documentary source that was available to me-the Annual Reports to the Board of Scientific Directors of The Rockefeller Institute for Medical Research-proved to be only slightly less formal in the presentation of the experimental facts. Therefore, for any touches of human interest in the story, I have had to rely on my memory of conversations with those who were personally involved. It was my good fortune to know well both of the original discoverers, William S. Tillett and Thomas Francis. When I joined Tillett at New York University in 1940 as a research fellow, he was chairman of the Department of Medicine but his laboratory remained across the street from Bellevue Hospital in association with his former department of bacteriology. Francis was then professor of bacteriology and the department was small enough so that I had about as much contact with him as I did with Tillett during my year there. I did not, however, have the foresight to get either of them to tell the detailed story of C-reactive protein, and I have recollections only of scattered comments that they made on the subject from time to time. The situation with regard to 0. T. Avery, in whose laboratory the discovery was made, was more favorable. His repertoire of inimitable discourses describing the development of the various paths of research in his laboratory included one on C-reactive protein. I was treated to this vignette on more than one occasion during my years in his laboratory, and I obtained from him my picture of the early events as well as my enduring interest in the phenomenon. The Avery laboratory in the Hospital of the Rockefeller Institute with its long sustained interest in the biology of the pneumococcus was a remarkable place, and in 1930 at the time of the first observations of Tillett and Francis on a C-reactive substance it was at an interesting stage of its development. The work showing that the specific soluble substances of the pneumococcal capsule were polysaccharides, which established the role of polysaccharides as antigens, was nearly complete. The studies on the isolation of an enzyme from a soil bacillus that hydrolyzed the type I11 polysaccharide had been initiated by Dubos and later served as a final proof that it was indeed the polysaccharide that carried the specificity and biological activity. Goebel’s elegant work on synthetic sugar antigens that further clarified the basis for this specificity was just beginning. Dawson’s paper confirming Griffith’s findings on transformation of pneumococcal types had appeared in 1929, and the further struggles with this subject, which ultimately became a major concern of the laboratory by the end of the decade, 1

Pneumothorax in patients with AIDS

Eighty-seven inpatients were treated for 93 episodes of Pneumocystis carinii at St Marys Hospital between January 1989 and December 1990. During this period, 298 patients with the acquired immunodeficiency syndrome (AIDS) were treated at this hospital. Sixteen episodes of pneumothorax occurred and 12 of these, occurring in ten patients, were unrelated to procedure. In six of 12 (50%), the pneumothoraces occurred concurrently with Pneumocystis carinii pneumonia (PCP) and in ten (83%) cases there was a past history of PCP. Bilateral pneumothorax occurred in five cases (42%). In seven (58%) of the cases, patients had been using aerosolized pentamidine as prophylaxis for PCP. This retrospective study confirms the association of pneumothorax with current PCP and also shows an association with previous infection. The use of aerosolized pentamidine was not associated with pneumothorax development. It is important to suspect pneumothorax in a patient with PCP who deteriorates acutely. The high incidence of bilateral pneumothorax means that pleurodesis should be considered early.

Radiological features of AIDS related cholangitis

Cryptosporidial infection is one of the recognised causes of diarrhoea in AIDS patients. It may also produce biliary tract disease. Fifteen out of 250 (6%) AIDS patients seen at our hospital had Cryptosporidial enteritis and five of the 15 (2% total) had clinical evidence of biliary tract disease. The radiological findings in these five patients are presented. Ultrasound examination of all five patients showed abnormalities in the biliary tree; five had dilatation and irregularity of the intra- and extrahepatic bile ducts with focal strictures, four had gall-bladder wall thickening, two had thickening of the common bile duct wall, two patients showed areas of increased reflectivity in the periductal regions of the liver and two had pancreatic duct dilatation. ERCP in one patient confirmed the ultrasound findings and Cryptosporidium oocytes were isolated from the collected bile. We conclude that Cryptosporidial infection in the biliary tree can produce distinctive appearances on ultrasound which may well obviate the need for more invasive investigations such as ERCP.

Trapped NH2 Radicals at 4.2°K

A study has been made of the electronic absorption spectrum of the NH2 radical trapped in an argon matrix on a liquid helium cooled surface. The radical is produced in a microwave discharge of argon mixed with a small amount of parent molecule, ammonia or hydrazine. The long effective absorbing path is illustrated by the presence of new bands of NH2, too weak to have yet been observed in the flash photolysis spectrum. That the radicals have also been found in moderate concentration from low‐pressure discharges containing hydrogen and nitrogen in many forms indicates that they are easily built up from smaller fragments, a fact which may be important in the explanation of the origin of these radicals in comets. The radical is positively identified by the excellent correlation between the low temperature spectrum and the gas‐phase spectrum recently analyzed by Ramsay, and in agreement with this analysis only alternate bands appear strongly at 4.2°K. The observed features, which represent rotational lines of ...

Mercury 3P1–1S0 Transition in Solid Rare Gases

It is shown that the gross shifts in the spectrum of the Hg 3P1 ← 1S0 transition of Hg in solid‐rare gases can be correlated by considering the difference in the interaction potential between the lattice and the Hg atom in the 3P1 and 1S0 states, providing the distortion of the lattice caused by the Hg atom is taken into account. In Ar, Kr, and Xe the spectrum can consist of three separate components. It is quantitatively shown that one of the components arises from relatively isolated Hg atoms while the other two components result from Hg atoms having nearest neighbor Hg atoms.

Laboratory aids in the diagnosis of rheumatic fever and in evaluation of disease activity

T HERE are two ways in which the laboratory might be expected to give assistance in dealing with the problem of rheumatic fever. The first is in the diagnosis of the disease, and the second is in guiding the medical management of the disease by providing an index of rheumatic activity. At the present time completely satisfactory laboratory procedures have not been developed in either of these categories. Thus there is still no specific diagnostic test for rheumatic fever, and there is no test for rheumatic activity that can be relied upon when the patient is under full therapy. However, there are laboratory procedures available which, despite their limitations, can be of great value both in diagnosis and management of the disease. The purpose of this paper is to emphasize the most practical and generally applicable of these procedures and to consider their interpretation and evaluation. The classic and readily recognized cases of acute rheumatic fever represent only a portion of the total cases, and diagnosis frequently presents a difficult clinical problem in the others. Because of the diversity of the manifestations of the disease and the variability of the combinations in which they can occur, it is not possible to apply any simple formula in arriving at a diagnosis. The large number of disease entities that have been confused with rheumatic fever and that must be considered in differential diagnosis emphasize the diagnostic difficulties. It is evident that in a situation of this kind a specific diagnostic test would be of inestimable value. It is not necessary that such a test be based upon a thorough understanding of the pathogenetic mechanisms in rheumatic fever, a fact that is adequately demonstrated by such procedures as the Wassermann test for syphilis and the heterophile antibody test as employed in the diagnosis of infectious mononucleosis. However, up to the present time a procedure of this type has not been developed to assist in the diagnosis of rheumatic fever. In the absence of a specific test for rheumatic fever the laboratory is still able to make an important contribution by supplying evidence concerning the occurrence of recent streptococcal infections. During the past few decades the relationship between group A streptococcal infections, usually streptococcal pharyngitis or tonsillitis, and rheumatic fever has become firmly established. The time relationships between the precursory bacterial infection and the onset of the rheumatic attack have been clearly defined, and the pattern is sufficiently reproducible to provide a basis for diagnostic procedures. The bacteriologic isolation and identification of group A streptococci is of only limited value in this regard. Due to the fact that a period of several days to several weeks intervenes between the acute bacterial infection and the onset of rheumatic fever, the offending organisms are frequently not recoverable after rheumatic symptoms have appeared. This has become increasingly true with the introduction of penicillin and other antibacterial agents, since one of these drugs has often been administered at some time during the prodromal period of the disease. Furthermore, the successful isolation of group A streptococci may give no information about the time of occurrence of an acute infection, because the carrier state can persist for an indefinite period. The demonstration of serum antibodies to individual antigens of group A streptococci has