Citations

SUMMARYHuman membrane cofactor protein (MCP; CD46) is a widely distributed complement regulator. In the mouse, expression of MCP is largely restricted to the testis while a related, widely expressed protein (Crry) appears to perform MCP's (CD46) regulatory activity. We have developed two mouse strains transgenic for human MCP (CD46) utilizing an ∼ 400 kb YAC clone carrying the complete gene. A third mouse strain was generated using an overlapping YAC clone isolated from a second library. The expression of human MCP (CD46) in these mouse strains was characterized by immunohistochemistry, FACS, Western blotting and RT-PCR. No differences were detected in the isoform pattern or distribution among the three strains, although the expression level varied according to how many copies of the gene were integrated. The expression profile closely mimicked that observed in humans, including the same pattern of isoform expression as the donor. In addition, tissue-specific isoform expression in the kidney, salivary gland and brain paralleled that observed in man. The transgenic mice expressed low levels of MCP (CD46) on their E, in contrast to humans but in line with most other primates. These mice should be a useful tool to analyse tissue-specific expression, to establish animal models of infections and to characterize the role of MCP (CD46) in reproduction.

SUMMARY We previously described autoantibodies against a UGA serine tRNA–protein complex (tRNP(Ser)Sec) in patients with type-1 autoimmune hepatitis [1] and now define the specificity and frequency of this autoantibody and the DNA sequence encoding the tRNA(Ser)Sec-associated antigenic protein. The presence of anti-tRNP(Ser)Sec antibodies was highly specific for type-1 autoimmune hepatitis, as 47·5% of patients were positive compared with none of the control subjects. To characterize the antigenic protein(s), we immunoscreened a human cDNA library with anti-tRNP(Ser)Sec-positive sera. Two clones (19 and 13) were isolated. Clone 19 encodes a protein with a predicted molecular mass of 48·8 kD. Clone 13 is a shorter cDNA, almost identical to clone 19, which encodes a 35·9-kD protein. Expression of both cDNAs was accomplished in Escherichia coli as His-tagged recombinant proteins. Antibodies eluted from both purified recombinant proteins were able to immunoprecipitate the tRNA(Ser)Sec from a HeLa S3 cell extract, demonstrating their cross-reactivity with the mammalian antigenic complex. Recent cloning data relating to the target antigen(s) of autoantibodies in autoimmune hepatitis patients that react with a soluble liver antigen (SLA) and a liver-pancreas antigen (LP) have revealed that these two autoantibodies are identical and that the cloned antigen shows 99% amino acid sequence homology with tRNP(Ser)Sec.

SUMMARYANCA directed against PR3 are highly specific for Wegener's granulomatosis and microscopic polyangiitis, and have been implicated in the pathogenesis of small vessel vasculitis. Most PR3-ANCA are directed against conformational epitopes on PR3. This study was designed to determine whether the cleavage of the N-terminal activation dipeptide of PR3 is required for the binding of PR3-ANCA. Recombinant PR3 (rPR3) variants were expressed in the epithelial cell line, 293. As confirmed by radiosequencing, the rPR3 secreted into the 293 cell culture supernatant is N-terminally unprocessed. Two enzymatically inactive rPR3 mutants were expressed in 293 cells: rPR3-S176A and δ-rPR3-S176A. rPR3-S176A contains the N-propetide Ala-2-Glu-1, δ-rPR3-S176A does not. Culture supernatants of rPR3-S176A and δ-rPR3-S176A expressing 293 cells were used as sources of target antigen for PR3-ANCA testing by capture ELISA. Forty unselected consecutive PR3-ANCA+ sera were tested. With δ-rPR3-S176A as antigen all 40 were recognized, compared with only 34 of 40 when rPR3-S176A served as target antigen. The majority of the serum samples contained a mixture of antibodies reacting with epitopes accessible on the mature and on the proform of PR3. In conclusion, the cleavage of the N-terminal activation dipeptide of PR3 is not an absolute requirement for recognition by all PR3-ANCA. However, a substantial proportion of PR3-ANCA recognize (a) target antigen(s) exposed only after the conformational change of PR3 associated with the N-terminal processing. In 15% of sera this PR3-ANCA subset occurred exclusively. PR3-ANCA subtypes can be differentiated using specifically designed rPR3 variants as target antigens, and non-haematopoietic mammalian cells without regulated secretory pathway can be used for their expression.

Abstract Background Papillary thyroid cancer (PTC) has a generally favourable prognosis, but elderly patients with distant metastases or extracapsular invasion fair poorly. In small studies with short follow-up, young patients presenting with such extracapsular invasion and pulmonary metastases have faired well. This retrospective study was undertaken to clarify the long-term prognosis of such patients with advanced PTC. Methods Twenty-one children and young adults (median age 14 (range 6–20) years) presenting with PTC and pulmonary metastases were treated at a single institution between 1947 and 1998. Mean maximal tumour diameter was 4·65 cm. Initial surgical treatment consisted of total thyroidectomy (n = 16), subtotal thyroidectomy (n = 4) and isthmectomy (n = 1), coupled with a variety of lymph node dissections (n = 20). After operation, 19 patients were treated with ablative and incremental doses of iodine-131 until disease free. All patients were placed on suppressive thyroid hormone after operation. Mean length of follow-up was 21 years (range 3 months to 47 years). Follow-up was less than 3 years in four patients. All patients have undergone post-treatment radionucleotide and radiological evaluation. Results Nine of the 21 patients developed recurrent disease. The risk of recurrence at 5 years was 39 (95 per cent confidence interval 14–57) per cent. Eight had cervical lymph node recurrence and no patient developed recurrent pulmonary disease. All patients with identifiable recurrent disease underwent selective lymph node resection, which involved multiple resections in four. At follow-up, 18 patients remain completely free of disease, one patient has recurrent cervical node disease and two patients have died. The disease-free survival at 5 years was 95 (95 per cent confidence interval 86–100) per cent. Cause-specific death occurred in a single patient who died from extensive local disease at age 29 years after 12 years of multiple cervical lymph node recurrences. Conclusion A stepwise treatment approach including total thyroidectomy, high-dose iodine-131 treatment and early surgical reintervention for suspected local recurrent disease allows long-term survival and frequent ‘cure’ for young patients with PTC and concomitant pulmonary metastases.

Abstract Background The authors have reported a newly recognized hypoglyacemic disorder, non-insulinoma pancreatogenous hypoglycaemia syndrome (NIPHS), which is characterized by postprandial hyperinsulinaemic hypoglycaemia, negative 72-h fast, negative transabdominal and intraoperative ultrasonography, spiral computed tomography and coeliac axis angiography, positive selective arterial calcium stimulation test (SACST), absence of insulinoma but presence of islet hypertrophy and nesidioblastosis, and relief of symptoms from gradient-guided partial pancreatectomy. Experience with the next five patients with this disorder (6–10; 1998–1999) compared with the original five (1–5; 1996–1998) is reported. Results Wide age range, male predominance, postprandial occurrence of symptoms, negative radiological localization, nesidioblastosis/islet hypertrophy, but no insulinoma characterized all ten cases. Response to SACST indicated widespread islet hyperfunction in patients 1 and 5; limitation to distribution of the SPA and GDA in patients 3, 4, 6 and 8, to distribution of the SPA in patients 2, 7 and 9, and to distribution of the SMA in patient 10. Except for patient 5, pancreatic resection to the left of the SMV was performed when only the SPA was positive on the SACST. Patients 5 and 8 have had recurrence of symptoms; they resolved within 3 months for patient 5. Conclusion NIPHS can usually be treated successfully with gradient-guided partial pancreatectomy.

Abstract Background Calciphylaxis is a rare, painful, life-threatening problem of cutaneous necrosis and refractory healing seen in patients with uraemia and secondary hyperparathyroidism. The pathogenesis involves abnormalities in calcium and phosphorus metabolism, and acute deposition of calcium in tissues. Methods The clinical course of 16 patients diagnosed with calciphylaxis at this institution from 1994 to 1998 was reviewed. Results Fourteen women and two men, with a mean age of 56 (range 39–70) years, presented with chronic renal disease of various causes, hyperparathyroidism and characteristic skin lesions. All patients underwent intensive medical therapy, including haemodialysis (n = 16), parathyroidectomy (PTX) (n = 7) and skin debridement of cutaneous lesions (n = 8). Mean preoperative serum values in surgical (PTX) versus non-surgical patients were: calcium 9·9 and 9·3 mg dl−1 (P = 0·25); phosphorus 5·8 and 4·9 mg dl−1 (P = 0·04); calcium–phosphorus product 61·6 and 45·2 (P = 0·03); and parathyroid hormone (PTH) 56·8 and 5·9 pmol l−1 (P = 0·0001) respectively. Mean postoperative values for calcium (8·7 mg dl−1), phosphorus (4·2 mg dl−1), calcium–phosphorus product (30·5) and PTH (4·0 pmol l−1) in surgical patients changed significantly (P < 0·05). Median overall survival was 9·4 months with 15 patients now deceased. Median survival was 14·8 and 6·3 months for PTX versus no PTX (P = 0·22), 14·1 and 6·1 months for skin debridement versus no debridement (P = 0·08), 12·4 and 6·6 months for proximal versus distal skin lesions (P = 0·60), and 6·5 and 13·9 months for diabetic versus non-diabetic patients was (P = 0·11). Conclusion Calciphylaxis appears to have a female preponderance with a very dismal prognosis. A multidisciplinary approach using frequent haemodialysis to normalize serum calcium and phosphorus levels, and local debridement of skin lesions seems prudent. PTX cannot be recommended routinely in all such patients unless severe secondary hyperparathyroidism with poorly controlled metabolic disturbance mandates surgery. The exact indications for PTX for calciphylaxis remain unclear.

We describe a 63-year-old smoker who suffered from intractable facial pain secondary to an underlying lung neoplasm. Data from 30 previously reported and similar cases are also summarized. The clinical triad of a smoker suffering from periauricular pain and an elevated ESR should alert the clinician to the possibility of an occult lung mass. In these cases a computed tomography of the chest should always be obtained. Previously refractory pain typically responds to surgical resection of the mass and/or radiation therapy.

The syndrome of orthostatic (low pressure) headaches is well described and most commonly occurs following deliberate violation of the dura (e.g. lumbar puncture). This syndrome can also occur spontaneously and results from the leakage of CSF. We describe three patients who suffered from spontaneous CSF leaks secondary to bony pathology of the cervical spine, and propose that this may be a more common aetiology than originally thought. Often these patients are difficult to manage medically, and surgery may be necessary for symptomatic relief.

Abstract Background Primary sarcomas of the liver are extremely rare in adults. Optimal therapeutic approaches remain unclear. Methods Twenty consecutive adult patients who had surgical treatment for primary hepatic sarcomas were reviewed. Patient age ranged from 23 to 80 years. Other than one patient with primary hepatic angiosarcoma who had a history of thorium dioxide colloid (Thorotrast) exposure 23 years before diagnosis, no predisposing causes were apparent. Nineteen patients had hepatic resection and one patient had an orthotopic liver transplant. No patient received neoadjuvant chemotherapy or radiotherapy but radiotherapy was delivered intraoperatively in one patient. Results Leiomyosarcoma was the most common histological type of sarcoma diagnosed (five of 20 patients), followed by malignant solitary fibrous tumour (four) and epithelioid haemangioendothelioma (three). Fourteen tumours were high-grade sarcomas and six were low grade malignancies. Thirteen patients developed a recurrence. Distant metastases (ten patients) and intrahepatic recurrence (six) were the predominant sites of initial treatment failure. Six patients received salvage chemotherapy. Histological grade was the only factor significantly associated with overall patient survival (P = 0·03). With complete resection, patients with high-grade tumours had a 5-year survival rate of 18 (95 per cent confidence interval 5–62) per cent compared with 80 (52–100) per cent for patients with low-grade tumours. The 5-year survival rate for all 20 patients was 37 (20–60) per cent. Conclusion Surgical resection is the only effective therapy for primary hepatic sarcomas at present. Better adjuvant therapy is necessary, especially for high-grade malignancies, owing to the high failure rate with operation alone.