STUDIES ON THE PATHOGENESIS OF STAPHYLOCOCCAL INFECTION : I. THE EFFECT OF REPEATED SKIN INFECTIONS

The influence of repeated staphylococcal infection of rabbit skin upon the characteristics of the experimentally induced lesion was studied. It was found that the repeated infection was associated with the development of delayed hypersensitivity unaccompanied by the appearance of demonstrable serum antibody. The delayed hypersensitivity to the staphylococcus resulted in an increased infectivity of the organism in skin of the sensitized animal, characterized by intensification of the lesions seen with large bacterial inocula and the induction of abscesses with inocula incapable of producing any lesion in normal rabbit skin. Similarly, the severity of experimentally induced pyoarthrosis was greater in sensitized than in normal rabbits. Induction of delayed hypersensitivity by vaccination of rabbits with washed heat-killed staphylococci resulted in the same increased severity of the infection and an increase in infectivity of the microorganism. In contrast to the observations of cutaneous and joint infection, the sensitized animals appeared to be less susceptible to severe infection of the anterior chamber of the eye. The role of immunity and hypersensitivity in staphylococcal infection is discussed and the possibility that non-specific inflammation may influence staphylococcal infection in the same way as specific hypersensitivity is indicated. Studies to further elucidate this are presented in the following pages.

STUDIES ON THE PATHOGENESIS OF STAPHYLOCOCCAL INFECTION : III. THE EFFECT OF TISSUE NECROSIS AND ANTITOXIC IMMUNITY

Necrosis of rabbit skin produced by thermal injury was found to result in a striking increase in local infectivity of staphylococci that were coagulase-positive and hemolytic, but no local increase in the infectivity of non-pathogenic staphylococci. Infection produced in necrotic burns extended beyond the area of burn and was characterized by hemorrhage, edema, and necrosis of contiguous normal skin. Such infections, however, never resulted in bacteriemia or metastatic abscesses, and there was no effect of the necrotic burn upon the infectivity of staphylococci injected into normal skin of the burned animal. Recovery of rabbits from severe burn infections was associated with the development of high titers of serum antibody to the alpha hemolysin or dermonecrotoxin of the staphylococcus. Thirty to 100 days after the initial burn infection, it was found that rabbits could no longer be infected in a necrotic burn, although infection induced in normal skin of these resistant animals was no different from that in normal rabbits. Immunity to infection by pathogenic staphylococci in necrotic burns could be induced by vaccination with potent alpha hemolysin toxoid, and this immunity was passively transferable with rabbit antiserum. No strain specificity was detected for this immunity in that immunization with toxoid prepared from bacteriophage type 52/42B/80/81 staphylococci protected animals against infection in a necrotic burn by other typable and non-typable staphylococci. Histopathological study of infected necrotic burns in normal rabbits showed extensive necrosis, hemorrhage, edema, and many masses of bacteria but leucocytic infiltration was observed only at the margin of the infection. In contrast, the infected necrotic burns in animals immunized with alpha hemolysin toxoid showed few bacteria and marked leucocytic infiltration throughout the burn. These experiments have, therefore, demonstrated a significant immunity to infection by pathogenic staphylococci in necrotic tissue but not in normal skin, associated with serum antibody to the alpha hemolysin or dermonecrotoxin of the bacteria. The implications of these findings are discussed.

Hypertrophy of the posterior longitudinal ligament in the thoracic spine

STUDY DESIGN

This is a case report of a patient with hypertrophy of the posterior longitudinal ligament (HPLL) in the thoracic spine. This patient was followed for 10 years after surgery.

OBJECTIVES

The purpose of this study was to report the long-term outcome of HPLL in the thoracic spine.

SETTING

Department of orthopedic surgery, Hiroshima Red Cross and Atomic-bomb Survivors Hospital, Hiroshima, Japan.

METHODS

A 58-year-old-woman with thoracic HPLL was reported. Magnetic resonance image (MRI) and computed tomography (CT) showed the expanded spinal cord compression from Th4 to Th12 due to HPLL. Anterior decompression and fusion (Th10-12) was performed. Histological findings of the surgical specimens showed thickening of the posterior longitudinal ligament with proliferation of chondroid tissue. The clinical outcome and the radiological findings (CT and MRI) were evaluated 10 years after surgery.

RESULTS

The patient was asymptomatic postoperatively. However, the subsequent CT examination revealed ossification of the previously hypertrophied posterior longitudinal ligament.

CONCLUSIONS

HPLL in the thoracic spine is a rare pathological condition causing myelopathy. The results of this study support the hypothesis that HPLL is one of the prodromal conditions of HPLL.

Analysis of fusion junctions of circularized chromosomes in Streptomyces griseus

A filamentous soil bacterium, Streptomyces griseus 2247, carries a 7. 8-Mb linear chromosome. We previously showed by macrorestriction analysis that mutagenic treatments easily caused deletions at both ends of its linear chromosome and changed the chromosome to a circular form. In this study, we confirmed chromosomal circularization by cloning and sequencing the junction fragments from two deletion mutants, 404-23 and N2. The junction sequences were compared with the corresponding right and left deletion end sequences in the parent strain, 2247. No homology and a 6-bp microhomology were found between the two deletion ends of the 404-23 and N2 mutants, respectively, which indicate that the chromosomal circularization was caused by illegitimate recombination without concomitant amplification. The circularized chromosomes were stably maintained in both mutants. Therefore, the chromosomal circularization might have occurred to prevent lethal deletions, which otherwise would progress into the indispensable central regions of the chromosome.

Chromosomal deletions in Streptomyces griseus that remove the afsA locus

We have recently constructed a physical map of the Streptomyces griseus 2247 genome using the restriction enzymes AseI and DraI, which revealed that this strain carries a 7.8 Mb linear chromosome. Based on this map, precise macrorestriction fragment and cosmid maps were constructed for both ends of the chromosome, which localized the afsA gene 150 Kb from the left end. Two afsA- mutants were found to have suffered chromosomal deletions that removed the afsA locus. The sizes of the deletions were 20 and 130 Kb at the right end and 180 and 350 kb at the left end, respectively. Hybridization experiments using cosmids carrying a deletion endpoint indicated that the ends of the chromosome in the mutants were fused to form a circular chromosome.

Presence of both stimulating and blocking types of TSH-receptor antibodies in sera from three patients with primary hypothyroidism

A case report of three patients with primary hypothyroidism who had potent TSH-binding inhibitor immunoglobulins (TBII) and both thyroid stimulating (TSAb) and thyroid stimulation-blocking antibodies (TSBAb) has been described. Two patients displayed symptoms and signs indistinguishable from those in primary myxoedema (cases 1 and 2), and another patient had a history of Graves' disease (case 3). TBII, TSAb and TSBAb activities were 90.0, 1084.2 and 94.5% in case 1, 91.5, 826.6 and 95.8% in case 2, 76.0, 230.0 and 95.0% in case 3, respectively (normal range, less than 11.0%, less than 145.0 and less than 22.0%, respectively. The results indicate that both stimulating and blocking types of TSH-receptor antibodies exist in these patients. The possible mechanism whereby hypothyroidism developed has been discussed.