Geographical distribution of amyloidosis in Papua New Guinea

During an 11 year period 73 cases of amyloidosis were diagnosed at Port Moresby General Hospital as a result of histological examination of autopsy or biopsy material. No case of amyloidosis came from either the Highlands or North Coast regions although these two areas together accounted for 16% of the medical admissions at the hospital and made up a similar percentage of Port Moresby's Papua New Guinean population. Within the sub-district in which Port Moresby is situated there was a much higher incidence of amyloidosis in the inland, more sparsely populated, census divisions of the sub-district. Aetiological factors which may be related to the common occurrence of amyloidosis in Papua New Guinea are discussed in light of the observed geographical distribution of cases.

Connective tissue origin of the amyloid-related protein SAA

Protein SAA is a serum protein related to the major constituent of secondary amyloid fibrils, protein AA, and has been suggested to be a precursor of the amyloid protein AA. In the present study, the origin of SAA was investigated by studying human fetal tissues and cultured human fetal fibroblasts with the indirect immunofluorescence technique. Anti-SAA antibodies reacted strongly with cultured fibroblasts producing a fine fibrillary cytoplasmic staining and with extracellular fibrils in loose connective tissues and vessel walls. The reactions were specifically inhibited by absorption with degraded amyloid material, isolated protein AA, isolated protein SAA, and sera from patients with elevated levels of SAA. In contrast, no inhibition was seen with amyloid fibril material devoid of AA protein or by human sera in which SAA was not detectable by double-diffusion tests. These observations showed that SAA-like material is produced by fibroblasts and indicate that it is a normal constituent of developing extracellular connective tissue fibers.

Amyloid fibril protein AA in Papua New Guinean amyloidosis

In this study of protein composition of amyloid fibrils isolated from eight patients representative of the spectrum of amyloidosis found in Papua New Guinea has been investigated. All fibril preparations, including three from patients with amyloidosis secondary to lepromatous leprosy and one from an unusual juvenile case of primary amyloidosis, contained the non-immunogobulin amyloid protein, protein AA. However, only 44% of thirty-six amyloid patients had detectable levels of the protein AA-related serum component, protein SAA. Alkali-degraded material from each of the fibril preparations failed to react in double immunodiffusion test with antiserum to the amyloid-related light chain VgammaV, but evidence was found for this immunoglobulin light chain-specificity in the serum of one patient.

Amyloid-related serum protein SAA in endotoxin-induced amyloidosis of the mink

The concentration of the amyloid AA-related serum protein (SAA) was markedly increased after endotoxin injections in mink, mouse, rabbit, and man. It was particularly studied during the development of endotoxin-induced amyloidosis of the mink. Protein SAA was markedly elevated in all mink 24 h after the first endotoxin injection but had fallen to relatively low levels before the onset of amyloidosis at about 4 wk. These results are consistent with SAA being a circulating precursor of the amyloid fibril protein, AA. However, both proteins may be derived by proteolysis from a common precursor.

Coexistence of protein AA and immunoglobulin light-chain fragments in amyloid fibrils

Coexistence of amyloid fibril protein AA and homogeneous immunoglobulin light-chain fragments was found in the isolated amyloid fibrils of two patients with amyloidosis secondary to rheumatoid arthritis. The light-chain amyloid fibril protein showed antigenic identity with a light-chain amyloid from a patient with primary amyloidosis, which was identified as the VlambdaIV subgroup by amino acid sequence analysis. In the amyloid fibrils isolated from another patient with primary amyloidosis there was a mixture of VlambdaIV and VlambdaV homogeneous immunoglobulin light chains. Thus, a mixture of protein AA had lambda light chains or two different types of homogeneous light chains may be found in the amyloid fibrils of some patients.

An experimental model in mink for studying the relation between amyloid fibril protein AA and the related serum protein SAA

Experimental amyloidosis was induced in mink by repeated injections with endotoxin. Amyloid fibrils extracted from liver and spleen were fractionated by gel filtration after treatment with guanidine-hydrochloride and a reducing agent, dithiothreitol. An elution profile very similar to that of human amyloid fibrils, having protein AA as a major component, was obtained. The mink amyloid protein eluted at a position similar to that of human protein AA was by amino acid composition and partial sequence studies shown to be very similar to the latter protein and was called mink protein AA. In addition, a protein AA-related component (protein SAA) was found in increased amounts in serum of amyloidotic mink, providing further evidence of the homology with human amyloids. Experimental amyloidosis in mink represents a suitable model for studying amyloid proteins and related serum components.

Cell-mediated immunologic status of healthy members of families with a history of leprosy

The cell-mediated immune status of 20 apparently healthy children from families with a history of leprosy has been studied. They have been compared with 20 age- and sex-matched controls from families with no history of leprosy. Lymphocyte transformation tests using PHA, PPD and lepromin and skin tests to lepromin, PPD and candida were carried out. No evidence of a depression of cell-mediated immunity in the children from families with leprosy was obtained. The only two children giving a negative Mitsuda lepromin skin test both subsequently developed leprosy in the succeeding 16 months. One was classified histologically as indefinite lepromatous and the other as borderline lepromatous. This emphasizes the practical significance of a negative lepromin skin test in an endemic leprosy area as a prognosis of clinical lepromatous leprosy.

Association of amyloidosis with erythema nodosum leprosum reactions and recurrent neutrophil leucocytosis in leprosy

Rectal biopsy in 190 inpatients at a leprosy hospital in the Highlands of Papua New Guinea disclosed 16 patients with secondary amyloidosis. This represented 20% of the patients who had had polar lepromatous leprosy (L.L.) for more than 2 years. Patients with amyloidosis characteristically had either a history of recurrent attacks of erythema nodosum leprosum (E.NH) reactions or chronic trophic ulcers. Levels of the serum component (protein SAA) antigenically related to the amyloid fibril protein AA were monitored, at varying intervals for three months, in lepromatous patients with E.N.L. reaction. The SAA levels rose during E.N.L. reactions in parallel with the neutrophil count. SAA occurred with greatest frequency among patients with LH, while most non-lepromatous patients with detectable SAA had chronic trophic ulcers. The correlation between raised neutrophil count and elevated SAA concentration, observed in this and other studies, suggests that neutrophils are associated with the production of SAA.

Isolation and characterization of amyloid-related serum protein SAA as a low molecular weight protein

With direct immunoprecipitation or gel filtration under dissociating conditions, amyloid-related serum protein SAA has been isolated as a low molecular weight protein from the serum of two patients with rheumatoid arthritis but without known amyloidosis. The isolated protein SAA showed antigenic identity and an amino acid composition that was similar, but not identical, with isolated fibril protein AA. Molecular weight estimations suggest that protein SAA is approximately 50% larger than protein AA and has a molecular weight of 14,000-15,000 daltons. Preliminary results indicate that protein SAA from a patient with amyloidosis has a similar small molecular weight subunit.

Factors affecting the activity of the lactate dehydrognease of Streptococcus cremoris

Studies with partially purified extracts of the nicotinamide adenine dinucleotide-linked l(+)-lactate dehydrogenase of Streptococcus cremoris US3 showed that fructose-1,6-diphosphate (FDP) was essential for the catalytic reduction of pyruvate in the pH range 5.0 to 7.0, outside of which the organism does not grow. In the absence of FDP, enzyme activity was observed only in the region of pH 8.0. The optimal pH for the oxidation of lactate was approximately 8.0 in the presence and absence of FDP. The FDP-activated enzyme was markedly inhibited by inorganic phosphate. The enzyme lost activity on standing at 5 C in alkaline triethanolamine, was quite stable at pH 6.0 to 6.5, and underwent irreversible denaturation below pH 5.0. Inorganic phosphate or FDP increased the stability of the enzyme in alkaline buffers. Some distinguishing properties of individual lactate dehydrogenases, activated by FDP, are discussed.

Formation of hydrogen peroxide by group N streptococci and its effect on their growth and metabolism

The formation of hydrogen peroxide by group N streptococci was found to occur through the action of a reduced nicotinamide adenine dinucleotide (NADH) oxidase which catalyzed the oxidation of NADH by molecular oxygen. The enzyme was activated by flavine adenine dinucleotide. Whereas some of the hydrogen peroxide formed was removed through the action of an NADH peroxidase, sufficient accumulated in media to inhibit the growth, respiration, and viability of these organisms. The amount of hydrogen peroxide which accumulated varied among strains, and this variation could be related to differences in the properties of the NADH oxidase present.