The degradation of serum amyloid A protein by activated polymorphonuclear leucocytes: participation of granulocytic elastase

To determine the role of inflammation in amyloidogenesis, we have studied the degradation of human serum amyloid A (SAA) protein by purified preparations of human blood polymorphonuclear leucocytes (PMN) and monocytes. When both PMN and monocytes were incubated in SAA-containing medium, the concentration of SAA as measured by a competitive anti-AA radioimmunoassay decreased over time. The rate of decrease of SAA was similar for both monocytes and PMN and there were no differences between four patients with amyloidosis and three normal controls. Resting PMN from normal volunteers were able to degrade SAA to smaller acid-soluble peptides within 16 hr while zymosan-activated PMN produced significant degradation within 1 hr (31%–50%). The supernatants from zymosan-treated PMN also caused marked SAA degradation within 1 hr.

The following enzyme inhibitors were able to prevent degradation of SAA by PMN supernatants; phenylmethylsulphonyl fluoride, a serine esterase inhibitor; α₁ anti-trypsin and soybean trypsin inhibitor; and acetyl-ala-ala-pro-val-chloromethyl ketone, an elastase inhibitor. The ability of a neutral lysosomal enzyme to degrade SAA was further confirmed by showing that purified PMN elastase significantly degraded ¹²⁵I-SAA.

We conclude that PMN contain one or more lysosomal enzymes capable of degrading SAA, an apoprotein of HDL₃ serum lipoproteins. Alteration in SAA proteolysis by activated PMN may contribute to the deposition of amyloid fibrils in the tissues of patients with chronic inflammatory disease.

     

Detection of altered H-ras proteins in human tumors using western blot analysis

H-ras p21 protein expression was investigated in bladder and colonic tumor tissues using an H-ras specific antibody in Western blot analysis. The specificity of this antibody to H-ras proteins was established using NIH/3T3 transfectants expressing oncogenic counterparts of the different ras gene family members. Use of this antibody to detect altered H-ras proteins was demonstrated using a panel of transfectants bearing different mutated H-ras genes and established cell lines previously characterized in transfection assays. Extension of this technique to direct analysis of human tumor material confirmed previous observations of H-ras activation within a group of bladder tumors and identified three more urothelial tumors expressing altered H-ras proteins. The altered migrational properties of these three were suggestive of point mutational events in 12 (1 case) and 61 (2 cases) codon hot spots. This study extends previous observations on the preferential activation of H-ras in urinary tract tumors and provides a rapid technique for evaluating the status of H-ras proteins in human tumor tissue.     

Role of Drosophila IKK gamma in a toll-independent antibacterial immune response

We have generated, by ethylmethane sulfonate mutagenesis, loss-of-function mutants in the Drosophila homolog of the mammalian I-kappa B kinase (IKK) complex component IKK gamma (also called NEMO). Our data show that Drosophila IKK gamma is required for the Relish-dependent immune induction of the genes encoding antibacterial peptides and for resistance to infections by Escherichia coli. However, it is not required for the Toll-DIF-dependent antifungal host defense. The results indicate distinct control mechanisms of the Rel-like transactivators DIF and Relish in the Drosophila innate immune response and show that Drosophila Toll does not signal through a IKK gamma-dependent signaling complex. Thus, in contrast to the vertebrate inflammatory response, IKK gamma is required for the activation of only one immune signaling pathway in Drosophila.     

Fine-needle aspiration cytology of Langerhans' cell histiocytosis (eosinophilic granuloma) of bone in children

Fine-needle aspiration (FNA) cytology of three cases of Langerhans' cell histiocytosis (eosinophilic granuloma [EG]) of bone in children (mean age--8.3 yr; range 5-11 yr) is presented. Two patients presented with vertebral lesions and the third had a femoral mass. Cytomorphologic features of EG were seen in all cases including Langerhans' cell histiocytes having oval to reniform shape nuclei with nuclear grooving and abundant pale cytoplasm. The background showed a polymorphic population of cells including neutrophils, lymphocytes, foamy histiocytes, and osteoclasts. Moderate numbers of eosinophils were seen in two cases, while eosinophils were sparse in the third case. Ancillary immunocytochemical (ICC) studies performed on the aspirated material demonstrated positive staining for S-100 protein (all three cases) and T-6 antigen (one case). Ultrastructural examination (EM) performed in one case demonstrated characteristic Birbeck granules in the histiocytes. A specific cytologic diagnosis was made in all cases, enabling proper chemotherapy in one case, surgical excision in another and spontaneous resolution in the third case. Our experience demonstrates that FNA cytology can make a definitive diagnosis of EG, especially when coupled with ancillary studies such as ICC and EM on the aspirated material.     

Multilocular renal cyst. A hamartoma with potential for neoplastic transformation?

Multilocular renal cyst is a pathologically distinctive lesion of uncertain pathogenesis that usually presents as a large abdominal mass in male infants or middle-aged women. We performed detailed light and electron microscopic studies of three nephrectomy specimens that contained multilocular cysts and attempted to correlate their morphology with various theories of pathogenesis. In one of our cases, a microscopic focus of clear cells that resembled renal cell adenocarcinoma was observed in the wall of one locule. Although such a finding has been reported previously, the lack of well-documented cases with metastases suggests that the prognosis for patients with this lesion remains uniformly excellent.     

The utility of ancillary studies in pediatric FNA cytology.

We evaluated the diagnostic contribution of adjunct studies performed on aspirated material in the work-up of pediatric fine-needle aspiration (FNA) biopsies. Ancillary studies were performed on 54 of 136 (39.7%) pediatric FNA biopsies during a 5-year period. In 23 (16.9%) cases, immunocytochemical (ICC) studies, consisting of immunoperoxidase staining of direct smears and/or cell blocks or flow cytometric immunophenotyping, were performed. The studies were adequate in 14 cases (60.9%), suboptimal in five cases (21.7%), and inadequate in four cases (17.4%). Of the adequate and suboptimal cases, the ICC data helped to narrow the differential diagnosis or classify the disease process in eight cases (42.1%), confirmed cytologic impression in nine cases (47.4%), and gave contradictory results in two cases (10.5%). Adequate material for electron microscopy (EM) was obtained in 14/19 cases (73.7%). Ultrastructural studies were diagnostic, or helped classify the disease process in five cases (35.7%), confirmed the cytologic impression in four cases (28.6%), helped exclude diagnostic considerations in three cases (21.4%), and were judged to be non-contributory in two cases (14.3%). Cytogenetic studies revealed six of seven cases (all neoplasms) to have abnormal karyotypes. Special stains for organisms performed on smears from 25 cases including Ziehl-Neelsen, Gomori methenamine silver (GMS), Gram, and Warthin-Starry (WS) were negative except for 1/16 GMS and 4/9 Gram stains. In summary, we found that with appropriate case selection, ancillary studies performed on aspirated material can provide useful information in pediatric FNA cytology.