Biomedical subjects
Publications and source records attributed to K W Chan.
A 29-year-old woman presented with diffuse pulmonary nodular amyloidosis and was subsequently diagnosed as having Sjögren's syndrome. We believe that this is the first case of Sjögren's syndrome presenting with secondary amyloidosis of the lung.
Lymphocytes activated by antigen receptor cross-linking or phorbol esters adhere avidly to surfaces bearing intercellular adhesion molecule 1 (ICAM-1) through the adhesion receptor lymphocyte function-associated antigen 1 (LFA-1). It is not known whether avid adhesion by stimulated lymphocytes is due to higher affinity binding of ICAM-1 or due solely to post-receptor mechanisms. We have used a recombinant, soluble form of the ICAM-1 molecule to measure the affinity of binding to LFA-1 on unstimulated T cells and T cells stimulated with phorbol esters. The affinity was found to be too low for direct measurements, requiring instead the use of competition protocols in which ICAM-1 competes for binding with radiolabeled Fab from a monoclonal antibody specific for LFA-1. By analysis of the equilibrium and kinetics of competitive binding, we found that the affinity on unstimulated T cells is very low, about 100 microM. Activation of the T cells by phorbol esters caused a small increase in average binding affinity. Further analysis suggested that the change in average affinity reflected the conversion of a fraction of LFA-1 molecules to a state with a 200-fold higher affinity.
OBJECTIVE: To determine whether there is a secular decline in the incidence of rheumatoid arthritis (RA), as has been suggested by previous studies. METHODS: In the absence of comprehensive data in the United States population, we estimated RA incidence in a health maintenance organization population from 1987 through 1990 and compared the rates with those in an earlier, similarly performed study from Rochester, Minnesota, which covered the years 1950 through 1974. RA estimates were based on our review of medical records of patients who had been diagnosed as having RA or related diseases during the period of January 1, 1987 through December 31, 1990. RESULTS: Annual age-standardized incidence of classic or definite RA (according to the American College of Rheumatology [formerly, the American Rheumatism Association] 1958 criteria) in patients aged 18 or older was 22 per 100,000 in men and 60 per 100,000 in women. The incidence of RA increased with age, with a marked increase in women older than 50. CONCLUSION: We found no secular change in RA incidence compared with the similarly ascertained historical data.
We propose an equilibrium model to assess the dispensing pattern of non-steroidal anti-inflammatory drugs (NSAIDs) among members of a health maintenance organization. The model incorporates observed patterns of patient switching among NSAIDs and identifies an implicit equilibrium distribution of drug dispensing, which may be used both to identify aberrations in prescription practice and to forecast the expected utilization of newly introduced drugs. NSAID dispensing patterns were stable for most quarters from 1987 to 1990. Introduction of two new NSAIDs and initiation of a pharmacy co-payment coincided with transient perturbation of the patterns. Dispensings of recently introduced NSAIDs achieved their equilibrium values in less than 2 years.
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Long-term results of gastrocystoplasty had not been reported in the literature. The results of 10 patients (7 augmentation and 3 replacement) during 15 years were reviewed. All patients voided spontaneously and achieved daytime continence. Enuresis occurred in 3 patients. Median peak flow rate and post-void residual urine were 16.0 ml. per second and 10 ml., respectively. Average cystometric capacity was 554 ml. and median pressure at full capacity was 46 cm. water. Phasic contractions resulted in pressures higher than 50 cm. water in 4 patients. Small capacity, absence of bladder sensation and high pressure were identified as risk factors for a poor result. Routine urine culture was positive in 20.5%. Urine mucus content remained low. Electrolyte disturbance, histopathological abnormalities and ulcer syndrome related to hypergastrinemia were absent. The data showed that antral gastrocystoplasty is superior because of the low infective complication rate, ability to empty and absence of metabolic disturbance.
In this report, we describe four cases of inflammatory pseudotumor of the liver and review the literature of this disease entity. The age of our patients ranged from 31 to 35 years (mean, 33 years). Two had fever, weight loss, and upper abdominal pain. The other had an incidental 1-cm nodule in the liver found during left hemihepatectomy for recurrent attacks of cholangitis. The preoperative clinical diagnoses in the former two cases were hepatocellular carcinoma. The patients had unremarkable recovery after resection. Grossly, the tumors showed a variegated appearance with areas of hemorrhage and necrosis and resembling hepatocellular carcinoma. Microscopically, the tumors were composed of a polyclonal population of reactive plasma cells and abundant plump spindle cells. The latter expressed vimentin but stained negatively for actin, desmin, and myosin. Ultrastructurally, these plump spindle cells showed features of fibroblastic differentiation. Forty-seven cases of inflammatory pseudotumor of the liver have been reported, 35 in males and 12 in females (male-to-female ratio of 2.9). The patients had a wide age range (10 months to 83 years; mean, 37 years). The most common symptoms were fever, upper abdominal pain and a space-occupying lesion in the liver. Surgical excision was curative. A few patients responded to antibiotic and steroid treatment. The recognition and distinction of this entity from hepatocellular carcinoma and other malignant tumors is particularly important in order to avoid unnecessary extensive surgery.
A study of renal tumours filed in the pathology department of a regional hospital in Hong Kong during 1971-1990 showed 6 cases of surgical emergency due to spontaneous rupture of the kidney by tumour. All occurred as a complication of renal angiomyolipoma, a rare tumour or hamartoma. A literature review showed that the renal tumour most frequently reported to cause spontaneous rupture was renal carcinoma. Chinese patients appear to have more renal ruptures due to angiomyolipoma than to renal carcinoma. It is proposed that intra-operative frozen section diagnosis should be sought, when this can be safely performed, in cases of rupture of the kidney by tumour. Surgery aiming at conserving functional renal parenchyma is appropriate for benign lesions such as angiomyolipoma.
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A case of IgD myeloma together with the existence of myelofibrosis is presented. More interesting is the concurrent presence of cast nephropathy, light chain deposition and amyloidosis in the kidney. Peculiar light-microscopic, immunohistochemical, immunofluorescence and ultrastructural findings were also noted. The possible mechanisms and implications for such findings were discussed. This case was analyzed together with a review of local pictures of renal involvement in multiple myeloma.
A novel renal complication was reported in a patient with angiofollicular lymph node hyperplasia (Castleman's Disease), who developed acute renal failure due to membranoproliferative glomerulonephritis. Renal biopsy showed marked mesangial hyperplasia, basement membrane thickening with subendothelial electron-dense deposits, interstitial plasma cell infiltration, and glomerular deposition of IgM and complement components. A resolution of systemic manifestations and an improvement in renal function followed prednisolone and azathioprine therapy. Disease relapse, with increasing proteinuria and the development of factor 8 inhibitor, occurred 3 months later. Sustained remission was achieved with prednisolone and cyclophosphamide therapy, which were given for 42 and 12 months, respectively. Renal biopsy during remission showed significant resolution of the mesangial hyperplasia and disappearance of interstitial plasmacytic infiltration as well as subendothelial electron-dense deposits.
To appraise the frequency, clinical features and prognosis of adult polycystic kidney disease (APKD) in Hong Kong, 41 Chinese patients who had an autopsy diagnosis of APKD were studied retrospectively. The APKD patients constituted 0.295% of 13,890 (or one in 339) autopsies performed during the study period (1964-1991). The frequency of APKD in autopsied populations in Western countries varies from one in 261 to one in 1,019 with an average of one in 503. Nineteen (46%) patients reached end-stage renal disease (ESRD) at the time of death. Ruptured berry aneurysm caused death in 3 patients while 3 others had spontaneous intracerebral hemorrhage. Left ventricular hypertrophy was found in 24 (59%) patients. Polycystic liver was present in 26 (63%) patients. This frequency was higher than the 4% to 60% (average 47%) reported in similar studies conducted in Western countries. The probability of patients being alive and without ESRD, estimated using a life table analysis, was 83%, 54%, 32% and 12% by the age of 40, 50, 60 and 70 respectively. No difference in frequency, clinical features and survival between male and female APKD patients could be demonstrated.
A polypoid fibro-osseous nodule arising from the soft tissues of a toe of a 17 yr old man is described. Initial partial excision of the nodule led to a wrong diagnosis of pyogenic granuloma. The mistaken diagnosis was based on finding an extensively ulcerated polypoid nodule with a core of fibrovascular tissue which resembled granulation tissue. The fast growing lesion recurred twice within 4 mths following incomplete excisions. Bony destruction of the distal phalanx was noted radiologically at the second recurrence. The rare lesion is an example of fibro-osseous pseudotumor of the digits, sometimes described as pseudomalignant osseous tumor of the soft tissues. It is curable by complete local resection. The importance of recognizing this lesion lies in its potential to be confused with parosteal or extraskeletal osteosarcoma. The fast growth rate of present case led to a strong clinical suspicion of malignancy. Incomplete excisions resulted in local recurrences rendering more extensive surgery necessary. There was no further recurrence 12 mths after the last excision.
A retrospective review was undertaken on all renal biopsies performed in Chinese children under 13 years of age in Queen Mary Hospital, Hong Kong from 1980 to 1990. Of 172 renal biopsies, 18 cases were diagnosed to be membranous glomerulonephritis. All were associated with hepatitis B virus infection. Fourteen patients presented with, and 3 others developed later nephrotic syndrome. Hematuria was a common feature (83%). Complement C3 was low in 5 cases and they became normal later. At last observation, 10 patients (59%) remitted, usually within 3 years. One had persistent proteinuria and 5 had nephrotic syndrome. One patient developed end-stage renal failure 12 years after onset of illness. All three female patients completely remitted. Of the 15 boys, 50% remitted whether they received steroid treatment or not. Two patients received interferon alpha-2a therapy. One achieved remission but HBsAg and HBeAg persisted. The other had transient seroconversion and clinical improvement but nephrotic syndrome returned after stopping treatment.
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Two Chinese boys, aged 3.5 and 5 years, developed nephrotic syndrome and were chronic carriers of hepatitis B virus surface antigen (HBsAg) and hepatitis B virus e antigen (HBeAg). Renal biopsy showed membranous glomerulonephritis and liver biopsy showed chronic persistent hepatitis. They were given interferon-alpha-2a at a dose of 5 MU/m2 on alternate days for 12 and 16 weeks after 2 years of persistent nephrotic syndrome. Patient 1 showed complete remission and resolution of hepatosplenomegaly, but his serum remained positive for HBsAg, HBeAg and hepatitis B virus DNA. Patient 2 showed only a transient clinical response and seroconversion from HBeAg to anti-HBe status. Although not always successful, interferon treatment should be considered in severe persistent nephrotic states, since there is at present no satisfactory treatment for this form of glomerulonephropathy.
Patterns of change in dispensings of non-steroidal anti-inflammatory drugs (NSAID) were evaluated from the pharmacy records of a health maintenance organization (HMO). Overall, 52.8% of NSAID prescriptions were followed by another NSAID prescription within 60 days. Among patients for whom NSAIDs were dispensed twice within 60 days, 15% received a different NSAID. Switching between NSAIDs was more frequent in younger age groups; there was no difference between males and females. Chronic and non-chronic indications for NSAID use were associated with similar probabilities of switches between drugs among repeat users. NSAIDs that were frequently switched to for lack of efficacy or for prior toxicity of other NSAIDs were not as a whole themselves associated with more frequent switches for the same reasons.
We evaluated the effects of the intravenous administration of anti-D, an immune globulin directed at the D antigen on erythrocytes that is purified from plasma from sensitized persons, on patients with idiopathic thrombocytopenic purpura. To determine the most effective dose, the duration of response, and the side effects of this therapy in children, we performed a multicenter cohort study of escalating doses of intravenously administered anti-D in children aged 1 to 18 years with chronic idiopathic thrombocytopenic purpura, defined as idiopathic thrombocytopenic purpura persisting for more than 6 months with a platelet count of less than 50 x 10(9) cells/L. Twenty-five Rh-positive children received increasing doses of anti-D as follows: day 1, 25 micrograms/kg; day 2, 25 micrograms/kg; day 7, 35 micrograms/kg; day 14, 45 micrograms/kg; and day 21, 55 micrograms/kg. Administration of anti-D was stopped after day 21 or when the platelet count rose to greater than 150 x 10(9) cells/L or the hemoglobin level was 100 gm/L. Platelet count was less than 50 x 10(9) cells/L in all children before treatment. A response was defined as an increase in the platelet count to more than 50 x 10(9)/L and a doubling of the pretreatment platelet count. Of 25 children, 23 (92%) had responses by day 7 of the initial treatment protocol. Eighteen children (72%) had platelet counts greater than 150 x 10(9) cells/L by day 7 after two doses of anti-D. Median duration of response was 5 weeks (range 1 to 24 weeks). Average drop in hemoglobin level was 13.7 gm/L; in one child (a nonresponder) hemoglobin value fell to less than 100 gm/L. No other untoward side effects were seen. Of the 23 children who responded, 21 were retreated with one dose of anti-D when platelet counts returned to baseline values of less than 50 x 10(9) cells/L; all but three of the children who underwent retreatment showed a response the second time. Sixteen children continued to receive intermittent anti-D therapy after completion of the study, and all continued to have excellent responses. We conclude that anti-D is a safe, effective, and relatively inexpensive therapy for childhood chronic idiopathic thrombocytopenic purpura.