[Successful immunoscintigraphic tumor detection with technetium 99m marked monoclonal anti-CEA antibodies]

Twenty patients aged 32-76 years (median 56 years) with various primary cancers or tumor recurrences (colorectal n = 14; lung, breast, medullary thyroid carcinoma n = 2, each) were studied with a technetium-99m labeled anti-CEA antibody. Intact monoclonal antibody BW 431/26 (Scintimum CEA-Tc-99m, Behringwerke AG, Marburg) was successfully labeled (Schwarz Method) by an instant 2-vial kit (labeling efficiency greater than 95% (TLC, HPLC), preserved immunoreactivity). The most frequent clinical indications were (1) the detection of tumor recurrences in patients with a steadily increasing serum CEA level (at a mean 2.3 years after complete removal of the primary tumor) but normal findings by conventional imaging modalities, (2) the search for extrahepatic tumor involvement in patients with known liver metastases scheduled for regional chemotherapy. Gamma camera scintigrams (planar and ECT) were performed 6-12 h and 18-26 h postinjection yielding a sensitivity of 95% (positive tumor contrast in 19/20 patients) with a specificity of 90% (positive predictive value 95%). Immunoscintigraphy successfully depicted tumor recurrences in 4/6 patients with elevated serum CEA values where all conventional imaging modalities had failed. The successful labeling of monoclonal antibodies with 99mTc represent an important step in clinical progress for the more practically orientated use of immunoscintigraphy and also opens new diagnostic fields.

Late conversion from steroids to azathioprine in cyclosporin-treated renal graft recipients

In renal graft recipients primarily treated with cyclosporin and low-dose methylprednisolone, withdrawal of the long-term steroid medication increases the likelihood of developing rejection episodes. In order to determine the predictive value of clinical parameters and routine prewithdrawal graft biopsies for the risk of rejection, the authors studied 141 kidney recipients from whom steroids were withdrawn 7-9 months after transplantation in a clinically stable situation. Both the quality of the HLA-match and the results of prospective graft biopsies were found to correlate significantly to the occurrence of acute rejection. In order to investigate the influence of additional azathioprine medication on the incidence of acute rejections in recipients not receiving steroids, immunosuppression was continued with cyclosporin monotherapy in 88 patients and with cyclosporin plus azathioprine in 53 patients. The risk of developing rejection episodes was significantly reduced from 48% after 1 year on monotherapy to 28% after the addition of azathioprine medication.

99Tcm-labelled anti-CEA monoclonal antibody for tumour immunoscintigraphy: first clinical results

Twenty patients with malignant carcinoembryonic antigen (CEA)-producing tumour recurrences (colorectal n = 14; breast, lung, medullary thyroid carcinoma n = 2, each) were studied by immunoscintigraphy using an intact monoclonal anti-CEA antibody (BW 431/26) labelled with 99Tcm by a new labelling technique (Schwarz Method). This novel approach allows an almost quantitative labelling of the antibody, which is first reduced using a thiol, lyophilized in purified form, and then reacted with a stannous salt component before 99Tcm-pertechnetate binding. The labelling efficiency (as controlled by TLC) was greater than 95%, the in vitro stability at least 6 h. The imaging results (planar and SPECT) yielded a sensitivity of 91%, a specificity of 87% and a diagnostic accuracy of 90%. These first promising clinical results trigger the hope that the successful labelling of monoclonal antibodies with 99Tcm is a decisive step towards the more practically orientated use of tumour immunoscintigraphy.

Long-term treatment and prognosis of rapidly progressive glomerulonephritis

Short-term prognosis of rapidly progressive glomerulonephritis (RPGN) has improved since immunosuppressive therapy was introduced. The long-term course of the disease was investigated in 46 consecutive and unselected patients over a period of 15 years (1970-1986) with a mean observation time of five years (+/- 45 months). Most of the 46 patients had idiopathic RPGN (61%). Initially, hemodialysis needed 25 of the 46 patients (54%). Immunosuppressive therapy (plasma exchange, methylprednisolone pulses, steroids, cyclophosphamide, azathioprine) was administered in 36 of the 46 patients (78%). A remission was achieved in only 19 of the 36 patients who received immunosuppression (53%) and no spontaneous improvement was seen. Factors indicating poor prognosis were initial high serum creatinine, high percentage of crescents in glomeruli, glomerular sclerosis, and immunohistologic staining of the IgG at the tubuli. In 11 patients with remission, immunosuppression was discontinued and 6 had a relapse. Long-term immunosuppression was given to 8 patients with remission. Their renal function was not normal (creatinine 240 +/- 77 mumol/l), but none had a relapse (p = 0.01). It is concluded that the treatment of RPGN requires long-term attendance and repeated immunosuppression comparable to a systemic immune disease.

Radioimmunoimaging for diagnosis of bone marrow involvement in breast cancer and malignant lymphoma

Granulopoietic bone-marrow was scintigraphically imaged in 15 patients with carcinoma of the breast and known skeletal metastases, 10 patients with malignant lymphomas, and 15 controls without suspected malignant disease, with a technetium-99m labelled murine monoclonal IgG1 antibody directed against nonspecific cross-reacting antigen (NCA-95) and carcinoembryonic antigen. Immunoscintigraphy revealed more lesions than did bone scanning in both patient groups. This method offers a sensitive, cost-effective, and easy-to-perform whole body technique for evaluating metastatic spread.

Progression of renal failure in analgesic-associated nephropathy

The factors that influence the progression of renal failure in analgesic-associated nephropathy (AAN) still remain to be clarified. In this study, the actual analgesic intake (N-acetyl-p-aminophenol, NAPAP, i.e. acetaminophen in urine) and progression of renal failure (1/crea method) in 127 outpatients with various renal diseases were investigated over a period of 7-150 months. AAN was diagnosed in 57 of the 127 patients (44%). The NAPAP test was positive in 21% of the 57 AAN patients and in 3% of the 70 control patients with other renal diseases (p = 0.0001). The AAN patients presented with more advanced renal insufficiency, lost more weight, and had more severe hypertension as well as a higher mortality rate than the control patients (univariate analysis). Progression of renal insufficiency, as measured by regression analysis of the reciprocal of serum creatinine versus time and expressed as clearance loss per year, was more rapid in the AAN patients who were found positive for NAPAP (6.9 +/- 5.5 ml/min/year) than in the AAN patients who were found negative (4.1 +/- 11.0 ml/min/year) or in control patients with other renal diseases (5.1 +/- 14.9 ml/min/year). Multivariate analysis showed the more rapid clearance loss to be the most discriminating factor between the AAN patients who continued analgesic abuse of phenacetin-or acetaminophen-containing drugs and AAN patients who stopped. We therefore conclude that continued analgesic abuse promotes renal insufficiency in AAN. The progression of renal failure in AAN patients who stopped abusing analgesics, however, cannot be explained within the parameters investigated, i.e. urinary tract infection, hypertension, hyperalimentation, or papillary necrosis.

Exponential function for calculating saturable enzyme kinetics

Enzyme kinetics are usually described by the Michaelis-Menten equation, where the time-dependent decrease of substrate (-dS/dt) is a hyperbolic function of maximal velocity (Vmax), Michaelis constant (Km), and amount of substrate (S). Because the Michaelis-Menten function in its most general meaning requires an assumption of steady-state, it is less curvilinear than true enzyme kinetics. A saturation-type exponential function is more curvilinear than the hyperbolic function and more closely approximates enzyme kinetics: -dS/dt = Vmax [1 - exp(-S/Km)]. The mathematical representation of enzyme kinetics can be further improved by introducing a deceleration term (Vdec), to make the assumption of a steady state unnecessary. For the action of chymotrypsin on N-acetyltyrosylethylester, the Michaelis-Menten equation yields the following: Vmax = 3.74 mumol/min and Km = 833 mumol. According to decelerated enzyme kinetics, the values Vmax = 4.80 mumol/min, Vdec = 0.0118 mumol/min, and the association constant (Ka) = 0.00111/mumol are more nearly accurate for this reaction (where 1/Ka = 901 mumol approximately Km).

Exponential function for calculating saturable enzyme kinetics

Enzyme kinetics are usually described by the Michaelis-Menten equation, where the time-dependent decrease of substrate (-dS/dt) is a hyperbolic function of maximal velocity (Vmax), Michaelis constant (Km), and amount of substrate (S). Because the Michaelis-Menten function in its most general meaning requires an assumption of steady-state, it is less curvilinear than true enzyme kinetics. A saturation-type exponential function is more curvilinear than the hyperbolic function and more closely approximates enzyme kinetics: -dS/dt = Vmax [1 - exp(-S/Km)]. The mathematical representation of enzyme kinetics can be further improved by introducing a deceleration term (Vdec), to make the assumption of a steady state unnecessary. For the action of chymotrypsin on N-acetyltyrosylethylester, the Michaelis-Menten equation yields the following: Vmax = 3.74 mumol/min and Km = 833 mumol. According to decelerated enzyme kinetics, the values Vmax = 4.80 mumol/min, Vdec = 0.0118 mumol/min, and the association constant (Ka) = 0.00111/mumol are more nearly accurate for this reaction (where 1/Ka = 901 mumol approximately Km).

Quantitative considerations supporting the irrelevance of circulating serum CEA for the immunoscintigraphic visualization of CEA expressing carcinomas

Starting from the phenomenon that the amount of circulating CEA in patients' sera did not significantly influence immunoscintigraphic visualization of CEA expressing tumors, we built up an in vitro model to explain this phenomenon. Blocking experiments in this model system showed that the CEA specific MAbs BW 431/26 and BW 431/31 could not be inhibited in their binding to cell associated CEA, if they were preincubated with a 20 molar excess of serum CEA. In contrast, the CEA-NCA cross reactive MAbs could be inhibited in their binding to tumor associated CEA under identical conditions. These data combined with western blotting analysis of patients' sera and affinity constant determinations argue that conformational changes in serum CEA cause a decreased affinity of the CEA specific MAbs to serum CEA allowing a preferential binding to tumor associated CEA.

[Immunoscintigraphy of colorectal cancers and specific immunotherapy of pancreatic cancers using monoclonal antibodies]

The routine application of immunoscintigraphy for the detection of colorectal carcinomas is now possible thanks to the development of the BW 431/31-F(ab')2-DTPA-In-111 or the BW 431/26-Tc-99m kits. The quick tumor localization (6 hours p.i.), the specificity and sensitivity (approximately equal to 90%) as well as the lack of side reactions argue for the quality of the reagents. The change from I-131 labelled murine monoclonal antibodies (MAbs) to In-111 or Tc-99m immunoconjugates in kit form resulted in a reduction of radiation dose for the patient down to 20% (In-111) or to 5% (Tc-99m) of the dose applied using I-131 labelled MAbs. The BW 250/183-Tc-99m conjugate suited for the immunoscintigraphic detection of inflammatory processes by in vivo labelling of granulocytes possesses the same favourable characteristics. The specific tumor immunotherapy of pancreatic carcinoma using MAb BW 494 points to interesting effects which have to be statistically confirmed in future clinical trials.

Characteristics and clinical course of hemodialysis patients with analgesic-associated nephropathy

The knowledge of some characteristic findings on the personality of patients with analgesic-associated nephropathy (AAN) may facilitate diagnosis of the disease at an early stage. We therefore investigated the 144 patients at our hemodialysis center and compared the AAN patients (33%) with those having other kidney diseases (controls). Patients with AAN were older (60 +/- 10 vs 52 +/- 15 years, p less than 0.001) and predominantly women. Acetaminophen and metamizol metabolites were detected more frequently in blood from the AAN patients than in that from the controls (25% vs 3%, p = 0.002). More AAN patients were smokers, and they more frequently complained of vague symptoms (pain, sensitivity to changes in weather, insomnia) and also more frequently requested prescriptions for analgesics, hypnotics, laxatives, stomachics and antipruritics. Because they were older, AAN patients had fewer occupational and financial problems. The compliance of the AAN patients was significantly better with respect to important dialysis parameters such as weight gain between dialysis treatments (3.6 +/- 1.3 vs 4.0 +/- 1.3% body weight, p less than 0.05) and diastolic blood pressure (81 +/- 12 vs 86 +/- 12 mmHg, p = 0.025). Despite an older age and higher morbidity, the cumulative 17-year survival rate of the AAN patients did not differ from that of the controls. We conclude that AAN patients have characteristic personality traits. Their better compliance, adjustment to the hemodialysis situation and social conditions are responsible for their good survival on hemodialysis.

[Cumulative functional rates of orthoptic dialysis fistulas and interposition grafts]

The function of 221 dialysis shunts was investigated retrospectively in 111 patients of an outpatient haemodialysis centre. The mean age of the patients was 58 years. Of 221 recorded shunts, 171 were direct arteriovenous fistulas, while 50 were interposition grafts. The longest observation period was almost 20 years (227 months). The cumulative function rate was evaluated by the life table method; primary patency (until first revision) was differentiated from total function (revisions included). The direct fistulas as compared to the grafts had a significantly (P less than 0.05) higher primary function rate (median 35 vs. 13 months) and after 36 months also a significantly longer total function (median 76 vs. 28 months). Complications were significantly (P less than 0.05) more frequent in grafts than in fistulas (61/50 vs 120/171). Surgical revisions of fistulas failed significantly more often (P less than 0.05) than revisions of grafts (137/171 versus 26/50). Grafts on the forearm had significantly worse results as compared to grafts or fistulas on the upper arm (P = 0.03). In contrast to age, sex and underlying disease of patients a blood pressure less than 130/70 mmHg was a significant risk factor for shunt failure (P = 0.002). Analysis of primary function shows (clearer than the total patency rate) that a direct fistula is a better vascular access in haemodialysis patients than a graft.

Determination of human thrombin-antithrombin III complex in plasma with an enzyme-linked immunosorbent assay

An enzyme-linked immunosorbent assay (ELISA) was developed for the determination of thrombin-antithrombin III complex (TAT) in human plasma. The test system follows the sandwich principle and uses two different antibodies directed against human thrombin and human antithrombin III, respectively. The antibodies bind selectively to the corresponding antigen moieties of TAT. The assay was calibrated with definite concentrations of preformed purified TAT added to TAT-poor plasma. The lower limit of sensitivity of the assay was 0.5 microgram/l. Mean coefficients of variation of 4.2% (intraassay) and 3.5% (interassay) were found for TAT concentrations between 2 and 60 micrograms/l. A reference range from 0.85 to 3.2 micrograms/l was calculated from TAT concentration in plasma samples from 88 healthy donors (mean value +/- SD: 1.45 +/- 0.4 micrograms/l). In plasma samples from patients with pulmonary embolism (n = 17), TAT concentrations between 3 and 25 micrograms/l were measured. In 15 patients with deep vein thrombosis, TAT was found up to 3 to 25 micrograms/l. From these data we conclude that measurement of TAT can be a sensitive parameter for specific detection of a latent activation of the clotting pathway.

Granulomatous interstitial nephritis after nonsteroidal anti-inflammatory drugs

Electrolyte and renal hemodynamic imbalance, acute interstitial nephritis with nephrotic-range proteinuria, papillary necrosis, tubular necrosis, and vasculitis are complications after intake of nonsteroidal anti-inflammatory drugs (NSAID). We report on 2 cases of biopsy-proven granulomatous interstitial nephritis with rapidly progressing renal insufficiency. Patient 1 was on ketoprofen for 7 months and indomethacin for 10 weeks before admission to hospital. The medication was not discontinued and renal insufficiency progressed to end-stage renal failure. Renal function did not respond to steroid and tuberculostatic treatment. Patient 2 was on diclofenac for 6 months and indomethacin for 7 weeks before admission to hospital. These drugs were withdrawn at diagnosis and renal function rapidly improved. We conclude that granulomatous interstitial nephritis may be a complication of NSAID medication indicating a cell-mediated immunologic disorder. False diagnosis (sarcoidosis, tuberculosis) may lead to end-stage renal disease (case 1). Discontinuation of medication obviates further therapy (case 2).

Increased procollagen III production in patients with kidney disease

Measurements of elevated procollagen III peptide (PIIIP) levels are used to monitor fibrosing activity in hepatic and various other diseases. Elevated PIIIP levels have also been reported in renal failure patients without such diseases. Therefore, the serum levels and renal clearance of PIIIP were investigated in 17 healthy volunteers and 100 patients with different types of acute (n = 15) and chronic (n = 85) kidney disease. PIIIP was measured by conventional and Fab radioimmunoassays. Median PIIIP levels in serum (18, range 5-55 ng/ml) and urine (34, range 1-110 micrograms/day) were significantly higher in kidney patients than serum (9, range 6-14 ng/ml) and urine levels (17, range 6-24 micrograms/day) in normal volunteers (p = 0.01). No significant differences (Kruskal-Wallis H test) were found, however, within the different kidney disease groups (acute, chronic/glomerulonephritis, interstitial nephritis). Median renal clearance of PIIIP-related peptides in kidney patients (1.5, range 0.5-2.4 ml/min) did not differ significantly (Wilcoxon U test) from that in normal volunteers (1.3, range 0.4-2.2 ml/min). These findings indicate that PIIIP elimination does not depend on renal function. PIIIP-related peptides in serum and urine, however, increase with renal failure irrespective of the activity or type of renal disease. This can be explained most probably by enhanced turnover of collagen type III by the affected kidney itself.

Effect of digitoxin on cardiac arrhythmias in hemodialysis patients

Digitoxin is considered a risk factor for ventricular arrhythmias in hemodialysis patients. In a randomized, crossover controlled study, 55 hemodialysis outpatients with sinus rhythm were prospectively investigated in two 48-h periods of electrocardiographic monitoring, one on and one off digitoxin or vice versa. The frequency of ventricular ectopic beats (mean +/- SD) which were found in 31 of 55 patients (56%), was slightly higher on hemodialysis (10 +/- 28 beats/h) than in the following 20 h (5.4 +/- 10 beats/h) and the next day off hemodialysis (3.6 +/- 6.6 beats/h); however, no difference was seen in patients on digitoxin during hemodialysis (10 +/- 29 beats/h), in the following 20 h (4.8 +/- 15 beats/h) and on the next day off hemodialysis (1.2 +/- 6.6 beats/h). The frequency of ventricular bigemini, polymorphous ectopies, couplets, more than 30 ectopies/h, salvos and tachycardias (10 vs 9 patients) on and off digitoxin was about the same (n.s., Fisher test). Supraventricular bigemini, salvos, tachycardias, and atrial fibrillation, however, occurred in significantly fewer patients on digitoxin (3 vs 13) than in those off digitoxin (P = 0.01, Fisher test). It is concluded that digitoxin does not increase the risk of ventricular arrhythmias in hemodialysis patients. Digitoxin, however, may have a beneficial effect on the supraventricular arrhythmias frequently observed in these patients.

Clinical significance of blood-device interaction in hemodialysis. A review

The syndrome of dialysis-associated leukopenia and complement activation by cellulosic membranes, including the so-called "first use syndrome", is reviewed and the pathophysiology of these phenomena is discussed. Subsequently the clinical side effects of hemodialysis, including dialysis-associated hypoxemia, are discussed. The hypoxemia, according to the authors, is mainly related to the loss of carbon dioxide through the dialyser. A minor role may be played by complement activation causing temporary sequestration of leukocytes in the pulmonary capillaries with (asymptomatic) peripheral leukopenia on the one hand and plugging of the pulmonary capillary bed with transient pulmonary hypertension and hypoxemia on the other. The question of dialysis-associated eosinophilia and ethylene oxide hypersensitivity is addressed as also contributing to the first use syndrome. The effects of interleukin release from monocytes and of contamination of the dialysis fluid are briefly discussed. The rare syndrome of silicone rubber spallation with hepato-and splenomegaly is also mentioned and finally the pathogenesis and symptomatology of the beta 2 microglobulin amyloidosis syndrome in long-term dialysis patients is presented.