Human acute leukemia cell line with the t(4;11) chromosomal rearrangement exhibits B lineage and monocytic characteristics

A cell line, designated RS4;11, was established from the bone marrow of a patient in relapse with an acute leukemia that was characterized by the t(4;11) chromosomal abnormality. The cell line and the patient's fresh leukemic cells both had the t(4;11)(q21;q23) and an isochromosome for the long arm of No. 7. Morphologically, all cells were lymphoid in appearance. Ultrastructurally and cytochemically, approximately 30% of the cells possessed myeloid features. The cells were strongly positive for terminal deoxynucleotidyl transferase. They were HLA-DR positive and expressed surface antigens characteristic for B lineage cells, including those detected by anti-B4, BA-1, BA-2, and PI153/3. Immunoglobulin gene analysis revealed rearrangements of the heavy chain and kappa chain genes. The cells lacked the common acute lymphoblastic leukemia antigen and antigenic markers characteristic of T lineage cells. The cells reacted with the myeloid antibody 1G10 but not with other myeloid monoclonal antibodies. Treatment with 12-O-tetradecanoyl- phorbol-13-acetate induced a monocyte-like phenotype demonstrated by cytochemical, functional, immunologic, and electron microscopic studies. The expression of markers of both early lymphoid and early myeloid cells represents an unusual phenotype and suggests that RS4;11 represents a cell with dual lineage capabilities. To our knowledge, RS4;11 is the first cell line established from t(4;11)-associated acute leukemia.     

Use of multiple T cell-directed intact ricin immunotoxins for autologous bone marrow transplantation

The monoclonal antibodies (MoAb) T101, G3.7, 35.1, and TA-1 were conjugated to intact ricin using a thioether linkage. These MoAb detect, respectively, the CD5[gp67], CD7[p41], CD2[p50], and [gp95, 170] determinants that are found in the vast majority of cases of T cell acute lymphocytic leukemia (T-ALL). The resulting immunotoxins (ITs) and an equimolar mixture of these ITs were evaluated as potential purgative reagents for autologous transplantation in T-ALL. Leukemic cell lines were used to compare the kinetics of protein synthesis inactivation mediated by each IT. The cells were treated with IT in the presence of lactose in order to block the native binding of ricin. The observed rates of protein synthesis inactivation correlated with target antigen expression detected by fluorescence-activated cell sorter analysis. Of the four ITs, T101-ricin (T101-R) exhibited the fastest rate of inactivation, followed in order by G3.7-ricin, TA-1-ricin, and 35.1-ricin. At concentrations greater than 300 ng/mL, a cocktail containing an equimolar amount of all four ITs (referred to as the four- IT cocktail) exhibited kinetics that were as fast or faster than those of T101-R. The long-term cytotoxic effects of individual ITs and the four-IT cocktail were evaluated using a sensitive clonogenic assay. Each IT was specifically cytotoxic and inhibited 1 to 4 logs of clonogenic leukemic cells at doses (300 to 600 ng/mL) that can be used clinically. The four-IT cocktail was highly cytotoxic; a concentration of 300 ng/mL inhibited greater than 4 logs of leukemic cells while sparing the majority of committed (CFU-GM, CFU-E) and pluripotent (CFU- GEMM) hematopoietic stem cells. The determination of both short-term kinetics of protein synthesis inactivation and longer-term inhibition of clonogenic growth allowed new insight into cell killing by IT. Our results suggest that ITs continue to act on clonogenic target cells for a period of three to five days. Interestingly, the four-IT cocktail was not as potent against clonogenic leukemic cells as T101-R alone, although it exhibited kinetics of protein synthesis inhibition that were as fast as those of T101-R alone. This finding suggests that internalized ITs may differ in the length of time they remain active within the cell. Our results also demonstrate the importance of using several different assays to evaluate IT reagents.     

Serum beta2-microglobulin and immunoglobulin levels in young hemodialysis patients

 Amyloidosis is a complication of long-term hemodialysis treatment. The major histological feature of hemodialysis-associated amyloidosis (HAA) is the deposition of amyloid fibrils in the affected lesions, due, in part, to elevated serum β₂-microglobulin (β2M) levels. In vitro studies reveal that serum immunoglobulin light and heavy chains co-deposit with β2M in tissues affected by HAA. Only one study of HAA has been performed in young dialysis patients. We therefore assessed risk factors for HAA in a group (n=30) of young (18.7±0.9 years) patients receiving chronic, uninterrupted hemodialysis using cellulose acetate membranes. All patients initiated dialysis before reaching 18 years of age. The pre-dialysis serum β2M level was 49.7±3.9 mg/l (normal 0–2.4 mg/l). Since serum albumin was normal (4.3±0.1 mg/dl) and serum protein/albumin was elevated (1.7±0.0, normal 1.2–1.5), indicating increased circulating protein, we assayed immunoglobulins in the same patients. The serum immunoglobulin levels (expressed as a percentage of the total level of serum proteins) were elevated (21.3±0.9%, normal 11.1%–21.0%). The Kt/v was 1.37±0.03, suggesting that the high levels of serum β2M and immunoglobulins were not due to inadequate dialysis in these patients. Patients with residual renal function (Kr) did display significantly lower serum levels of β2M (33.2±2.3, P=0.03). Furthermore, improved clearance of β2M correlated with higher values of Kr (r=0.914). In contrast, serum levels of immunoglobulin (22.6±3.7, P=0.5) were unaffected by Kr. In addition, there was no correlation between older age at onset of dialysis and serum levels of either β2M (r=0.107) or immunoglobulins (r=0.321). Finally, the length of time on dialysis had no effect on serum levels of either β2M (r=0.105) or immunoglobulins (r=0.092). Taken together, these results indicate that young hemodialysis patients may be at risk for HAA. Received: 13 January 1998 / Revised: 1 June 1998 / Accepted: 2 June 1998     

Are vitamin B12 and folate deficiency clinically important after roux-en-Y gastric bypass?

Although iron, vltamm B₁₂, and folate deficiency have been well documented after gastric bypass operations performed for morbid obesity, there is surprisingly little information on either the natural course or the treatment of these deficiencies in Roux-en-Y gastric bypass (RYGB) patients Durmg a l0-year period, a complete blood count and serum levels of iron, total iron-binding capacity, vltamin B₁₂, and folate were obtained in 348 patients preoperatively and postoperatively at 6-month intervals for the first 2 years, then annually thereafter The principal objectives of this study were to determine how readily patients who developed metabolic deficiencies after Roux-en-Y gastric bypass responded to postoperative supplements of the deficient micronutrient and to learn whether the risk of developmg these deficiencies decreases over time Hemoglobin and hematocrit levels were slgnificantly decreased at all postoperative intervals in comparison to preoperative values Moreover, at each successive interval through 5 years, hemoglobin and hematocrit were decreased signifiantly compared to the preceding interval Folate levels were significantly increased compared to preoperative levels at all time intervals Iron and vltamin B₁₂ levels were lower than preoperative measurements and remained relatively stable postoperatively Half of the low hemoglobin levels were not associated with iron deficiency Taking multivltamin supplements resulted in a lower incidence of folate deficiency but did not prevent iron or vitamin B₁₂ deficiency Oral supplementation of iron and vitamin B₁₂ corrected defiaencies in 43% and 81% of cases, respectively Folate deficiency was almost always corrected with multivitamins alone No patient had symptoms that could be attributed to either vitamin B₁₂ or folate deficiency Conversely, many patients had symptoms of iron deficiency and anenua Lack of symptoms of vitamin B₁₂ and folate deficiency suggests that these deficiencies are not clinically important after RYGB Conversely, iron deficiency and anemia are potentially serious problems after RYGB, particularly in younger women Hence we recommend prophylactic oral iron supplements to premenopausal women who undergo RYGB     

Lipid Levels: A Link Between Cardiovascular Disease and Osteoporosis?

Epidemiological observations support a positive relationship between cardiovascular diseases (CVD) and osteoporosis, where cholesterol has been indicated to be a possible link. Only a few studies have investigated the relation between lipids and BMD, but the association remains unclear. We studied the relationship between serum lipids and BMD of the calcaneus. A cross‐sectional population‐based study was performed, based on data from the Longitudinal Aging Study Amsterdam, including 620 men and 635 women, 65–88 yr of age. BMD was measured by quantitative ultrasound (QUS), velocity of sound (VOS; m/s), and broadband ultrasound attenuation (BUA; dB/MHz). Models were adjusted for age, body mass index, physical activity, smoking, alcohol, diabetes mellitus, hypertension, testosterone, and 25‐hydroxyvitamin D. No association was found between total cholesterol (TC) and QUS. Men and women in the highest quartile of high‐density lipoprotein cholesterol (HDL‐c) had a significantly lower QUS (men—VOS: β = ?20.8, p = 0.00; BUA: β = ?5.2, p = 0.02; women—VOS: β = ?18.6, p = 0.00) compared with men and women in the lowest quartile. An even stronger positive association was seen between TC/HDL‐c ratio and QUS (men—VOS: β = 21.8, p = 0.00; BUA: β = 5.5, p = 0.01; women—VOS: β = 19.2, p = 0.00; BUA: β = 3.6, p = 0.05). Our analysis shows that the lipid profile that is favorable in the prevention of CVD (i.e., high levels of HDL‐c and low TC/HDL‐c ratio) is unfavorable for QUS. These results indicate that HDL‐c levels do not explain the association between osteoporosis and CVD.     

Cognitive dysfunction after minor surgery in the elderly

BACKGROUND: Major surgery is frequently associated with postoperative cognitive dysfunction (POCD) in elderly patients. Type of surgery and hospitalization may be important prognostic factors. The aims of the study were to find the incidence and risk factors for POCD in elderly patients undergoing minor surgery. METHODS: We enrolled 372 patients aged greater than 60 years scheduled for minor surgery under general anesthesia. According to local practice, patients were allocated to either in- (199) or out-patient (173) care. Cognitive function was assessed using neuropsychological testing preoperatively and 7 days and 3 months postoperatively. Postoperative cognitive dysfunction was defined using Z-score analysis. RESULTS: At 7 days, the incidence (confidence interval) of POCD in patients undergoing minor surgery was 6.8% (4.3-10.1). At 3 months the incidence of POCD was 6.6% (4.1-10.0). Logistic regression analysis identified the following significant risk factors: age greater than 70 years (odds ratio [OR]: 3.8 [1.7-8.7], P = 0.01) and in- vs. out-patient surgery (OR: 2.8 [1.2-6.3], P = 0.04). CONCLUSIONS: Our finding of less cognitive dysfunction in the first postoperative week in elderly patients undergoing minor surgery on an out-patient basis supports a strategy of avoiding hospitalization of older patients when possible.     

Mesangial hypercellularity in children: presenting features and outcomes

Mesangial hypercellularity (MH), in the absence of sclerosis or immune deposition, was a common finding on renal biopsy in our center. We studied 66 children with predominant MH. Among all patients older than 2.7 years, blood pressure (BP) percentile and glomerular filtration rate (GFR) remained stable. Serum albumin (Alb) trended higher (3.0 ± 0.2 start vs. 3.4 ± 0.2 end g/dl, p = 0.06) and urine protein/creatinine lower (4.2 ± 0.9 start vs. 2.3 ± 0.9 end mg/mg, p = 0.18) at the end of the study period. The proportion with stage 1 CKD remained constant: 94% start vs. 92% end. At end, Alb was lower in patients referred for nephrotic syndrome (NS): 4.4 ± 0.3 hematuria vs. 4.2 ± 0.2 proteinuria vs. 2.8 ± 0.3 NS g/dl, p < 0.05 vs. both. Alb was lower (p = 0.03) and urine protein/creatinine trended higher in patients with diffuse foot-process fusion (FPF). Twenty-five percent of patients with focal FPF developed NS, all had relapses, and 63% were steroid sensitive (SS). All but one with diffuse FPF presented with NS; 86% had relapses (mean 1 year) and 63% were SS. GFR trended higher at the end in those with matrix thickening (mat) (119.6 ± 4.7 no mat vs. 129.1 ± 2.6 mat ml/min per 1.73 m², p = 0.1). Those without mat were less SS (59% no mat vs. 80% mat) and were more likely to require alkylating agents (Alk) for NS. Among those with positive immunofluorescence (IF), 82% had immunoglobulin M (IgM) alone; those with positive IF were more SS and needed Alk for NS. MH predicts a favorable prognosis. FPF predicts NS and multiple relapses.