Factors influencing the basal and recombinant human thyrotropin-stimulated serum thyroglobulin in patients with metastatic thyroid carcinoma

The serum thyroglobulin (Tg) level is the most sensitive marker for detecting residual thyroid carcinoma. We hypothesized that the basal and TSH-stimulated Tg levels in patients with metastatic thyroid carcinoma would reflect tumor volume, histological subtype, and location of metastatic lesions. A retrospective review of 417 thyroid cancer survivors undergoing evaluation for residual disease with the assistance of recombinant human TSH (rhTSH) was performed. In 169 patients with metastatic disease, we found that the basal Tg level directly correlated with the number of lesions, and that it was highest in patients with follicular and lowest in those with papillary thyroid carcinoma. The basal Tg level was highest in patients with bone metastases and lowest in those with cervical metastases. The fold increase in the serum Tg after rhTSH treatment was highest in papillary thyroid carcinoma and lowest in Hurthle cell carcinoma. The fold increase in Tg was not influenced by tumor volume or by the site of metastatic lesions. Multivariate analysis showed multiple interactions between factors, but did not identify one factor that significantly influenced basal Tg or fold increase. We conclude that the location and volume of metastases influence basal Tg, but not its responsiveness to rhTSH, whereas the histological type of carcinoma influences both basal Tg and responsiveness to rhTSH.

Early detection and prognosis of ovarian cancer using serum YKL-40

PURPOSE

YKL-40 is a secreted glycoprotein (chitinase family). We compared YKL-40 with two ovarian cancer serum markers, CA125 and CA15-3, for the detection of early-stage ovarian cancer.

MATERIALS AND METHODS

Serum YKL-40 levels were assayed by enzyme-linked immunosorbent assay for 46 healthy subjects, 61 high-risk individuals, 33 patients with benign gynecologic processes, and 50 preoperative patients subsequently diagnosed with predominantly early-stage ovarian cancer. Serum CA125 and CA15-3 values were obtained.

RESULTS

Median YKL-40 level was 28 ng/mL (range, 15 to 166 ng/mL) for healthy subjects, 36 ng/mL (range, 9 to 69 ng/mL) for high-risk individuals without prior cancer, 44.5 ng/mL (range, 5 to 133 ng/mL) for high-risk patients with prior breast cancer, and 38 ng/mL (range, 5 to 67 ng/mL) for individuals with benign gynecologic processes (P = NS). Median preoperative YKL-40 level for ovarian cancer patients was 94 ng/mL (range, 17 to 517 ng/mL; P <.0001 compared with normal and high-risk). YKL-40 was elevated (>/= 62 ng/mL) in 36 (72%) of 50 patients compared with 23 (46%) of 50 and 13 (26%) of 50 patients for CA125 and CA15-3 (P <.008). Twenty (65%) of 31 early-stage patients had elevated serum YKL-40 levels compared with 11 (35%) of 31 and four (13%) of 31 patients for CA125 and CA15-3 (P =.039). YKL-40 levels increased with stage (P <.005), regardless of grade, histology, or patient age. Patients with early-stage tumors with YKL-40 values more than 80 ng/mL had a worse prognosis (71% recurrence v no recurrence [P =.034]).

CONCLUSION

YKL-40 may represent a novel marker for the detection of early-stage ovarian cancer. YKL-40 levels in early-stage patients may also predict disease recurrence and survival. The utility of YKL-40 in detection of early-stage ovarian cancer deserves further investigation.

Systemic AL amyloidosis due to non-Hodgkin's lymphoma: an unusual clinicopathologic association

Systemic AL amyloidosis (AL) is a disorder in which light chains form fibrillar deposits, leading to organ dysfunction and death. Rarely, AL has been associated with non-Hodgkin's lymphoma (NHL), although this association has not been well characterized. We report a series of six patients with AL associated with NHL, primarily lymphoplasmacytic lymphoma. Organ involvement was variable, with frequent bulky lymphadenopathy and visceral cavity deposits, but no cardiac involvement. Positron emission tomography scans were negative. Bone marrow and lymph node biopsies showed a mixed population of CD20+ lymphoid and CD138+ plasma cells. Serum free light chains were elevated, and correlated with response to therapy. Immunoglobulin light chain variable region (Ig VL) germline gene use was typical for AL, reflecting previously observed correlations between germline gene use and organ tropism. Five patients received rituximab-based therapies with two responses. Two patients underwent autologous stem cell transplantation with one complete haematological response. Four patients survive at 10-132 months from diagnosis. AL with NHL has distinctive clinical features but employs the same Ig VL gene repertoire as AL with clonal plasma cell dyscrasias. Serial serum free light chain levels are useful for tracking response to therapy. Treatments aimed at both lymphoid and plasma cell components appear warranted.

High-dose calcitriol, zoledronate, and dexamethasone for the treatment of progressive prostate carcinoma

BACKGROUND

Preclinical and clinical data have suggested that high-dose calcitriol (1,25-dihydroxycholecalciferol) has activity against prostate carcinoma. Pulse-dosed calcitriol and dexamethasone may maximize tolerability and efficacy. The authors examined the toxicity of pulse-dosed calcitriol with zoledronate and with the addition of dexamethasone at the time of disease progression.

METHODS

Patients with progressive prostate carcinoma were eligible for the current study. In cohorts of 3-6 patients, calcitriol was administered for 3 consecutive days per week, starting at a dose of 4 microg per day. Doses were escalated to 30 microg per day. Intravenous zoledronate (4 mg) was administered monthly. Dexamethasone could be added to the regimen at disease progression. Toxicities, markers of bone turnover, plasma calcitriol levels, and clinical outcomes were recorded.

RESULTS

Thirty-one patients were treated in cohorts that were defined by the calcitriol dose administered (4, 6, 8, 10, 14, 20, 24, or 30 microg). Seven patients received dexamethasone. Three patients had their doses reduced due to calcium-related laboratory findings. Patients tolerated therapy well, even in the 30 microg cohort; therefore, a maximum tolerated dose was not defined. Peak plasma levels observed in the 24 microg and 30 microg cohorts ranged from 391 to 968 pg/mL. Minimal antitumor effects were observed.

CONCLUSIONS

Calcitriol was well tolerated at doses up to and including 30 microg 3 times per week in combination with intravenous zoledronate 4 mg monthly, with or without dexamethasone, in patients with progressive prostate carcinoma. Peak plasma levels in the 24 microg and 30 microg cohorts were greater than the levels associated with antitumor effects preclinically. Due to the cumbersome dosing schedule and the lack of significant activity observed, Phase II trials of this regimen are not planned.

Dietary manipulation, ethnicity, and serum PSA levels

OBJECTIVES

To examine whether a diet low in fat and high in fiber, fruits, and vegetables and ethnicity had any influence on serum prostate-specific antigen (PSA) levels, because serum PSA is a marker for the presence of prostate cancer. The incidence of prostate cancer increases with age, varies by ethnicity, and is greater among men with a first-degree relative who has had the disease. Large international variations in the rates of prostate cancer incidence and mortality, as well as the incidence changes in migrants and their offspring, also suggest that exogenous factors, including diet, have a strong influence on the development of this disease.

METHODS

We used data and blood samples from the Polyp Prevention Trial, a multicenter randomized trial designed to evaluate the impact of a diet low in fat and high in fiber, fruits, and vegetables on the recurrence of colorectal adenomas. Recruitment was from 1991 through 1994. Participants were followed up from their baseline recruitment date for 4 years. From this group, we identified 1100 white men and 97 black men who were 35 years of age or older, did not have prostate cancer, and had serum samples available for study.

RESULTS

At baseline, no difference was present in the fat intake for the black and white men (mean +/- SE, 90 +/- 3.6 g/day and 84 +/- 1.0 g/day, respectively; P = 0.15). The baseline serum PSA levels did not vary by ethnicity. For black men, the mean serum PSA level was 2.2 +/- 0.36 ng/mL compared with 2.0 +/- 0.07 ng/mL for white men (P = 0.64). Although all men assigned to the intervention group markedly reduced their fat intake by approximately 15% and increased their fruit and vegetable intake by approximately 2.25 servings per day, no difference was noted in the kinetics of the serum PSA levels by dietary intervention or race.

CONCLUSIONS

Although ethnic differences in the incidence of prostate cancer are well defined, we found no difference in the baseline fat intake among black and white men that might have contributed to this difference. Serum PSA, a marker often used in early detection programs for prostate cancer, was not associated with manipulation of the amount of fat in the diet, regardless of ethnicity.

Variation of serum prostate-specific antigen levels: an evaluation of year-to-year fluctuations

CONTEXT

Serum prostate-specific antigen (PSA) testing is frequently used in early detection programs for prostate cancer. While PSA testing has resulted in an increase in prostate cancer detection, its routine use has been questioned because of a lack of specificity.

OBJECTIVE

To determine whether year-to-year fluctuations in PSA levels are due to natural variation and render a single PSA test result unreliable.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective analysis of an unscreened population of 972 men (median age, 62 years) participating in the Polyp Prevention Trial (1991-1998). Five consecutive blood samples were obtained during a 4-year period and were assessed for total and free PSA levels.

MAIN OUTCOME MEASURE

Abnormal PSA test result based on a PSA level higher than 4 ng/mL; a PSA level higher than 2.5 ng/mL; a PSA level above the age-specific cutoff; a PSA level in the range of 4 to 10 ng/mL and a free-to-total ratio of less than 0.25 ng/mL; or a PSA velocity higher than 0.75 ng/mL per year.

RESULTS

Prostate biopsy would have been recommended in 207 participants (21%) with a PSA level higher than 4 ng/mL; in 358 (37%) with a level higher than 2.5 ng/mL; in 172 (18%) with a level above the age-specific cutoff; in 190 (20%) with a level between 4 and 10 ng/mL and a free-to-total ratio of less than 0.25 ng/mL; and in 145 (15%) with a velocity higher than 0.75 ng/mL per year. Among men with an abnormal PSA finding, a high proportion had a normal PSA finding at 1 or more subsequent visits during 4-year follow-up: 68 (44%) of 154 participants with a PSA level higher than 4 ng/mL; 116 (40%) of 291 had a level higher than 2.5 ng/mL; 64 (55%) of 117 had an elevated level above the age-specific cutoff; and 76 (53%) of 143 had a level between 4 and 10 ng/mL and a free-to-total ratio of less than 0.25 ng/mL.

CONCLUSION

An isolated elevation in PSA level should be confirmed several weeks later before proceeding with further testing, including prostate biopsy.

Phase I trial of high dose paracetamol and carmustine in patients with metastatic melanoma

Reduced glutathione (GSH) production by tumour cells has been proposed as a mechanism for resistance to alkylating agents. High levels of paracetamol can deplete intracellular GSH. We conducted a phase I trial of high dose paracetamol and carmustine (BCNU) in patients with advanced malignant melanoma to determine the optimal biological dose and the maximum tolerated dose (MTD) with the goal of increasing sensitivity to BCNU by GSH depletion. Groups of three to five patients received escalating doses of paracetamol (10, 15 or 20 g/m(2)) every 3 weeks. Every other cycle, BCNU (10 mg/m(2)) was given 6.5 h after administration of paracetamol and 45 min before a 20 h infusion of N-acetylcysteine. Once the MTD for paracetamol had been determined, the dose of BCNU was sequentially escalated in subsequent cohorts to 150 mg/m(2). GSH levels were measured in peripheral blood mononuclear cells (PBMCs) and, when available, in tumour biopsies. The MTD of paracetamol was 15 g/m(2). The dose of BCNU was safely escalated to 150 mg/m(2). The most common toxicity was grade II nausea/vomiting. At 15 g/m(2), peak paracetamol levels (median 253 microg/ml) were reached between 1 and 4 h. No changes in GSH levels in PBMCs were seen. There were two partial responses, including a dramatic decrease in hepatic metastases. Treatment of melanoma patients with paracetamol (15 g/m(2)) every 3 weeks and BCNU (150 mg/m(2)) every 6 weeks is safe. The observation of two partial responses has led to a phase II study to evaluate treatment with high dose paracetamol alone or in combination with BCNU.

Lack of effect of a low-fat, high-fruit, -vegetable, and -fiber diet on serum prostate-specific antigen of men without prostate cancer: results from a randomized trial

PURPOSE

To determine whether a diet low in fat and high in fruits, vegetables, and fiber may be protective against prostate cancer by having an impact on serial levels of serum prostate-specific antigen (PSA).

METHODS

Six hundred eighty-nine men were randomized to the intervention arm and 661 to the control arm. The intervention group received intensive counseling to consume a diet low in fat and high in fiber, fruits, and vegetables. The control group received a standard brochure on a healthy diet. PSA in serum was measured at baseline and annually thereafter for 4 years, and newly diagnosed prostate cancers were recorded.

RESULTS

The individual PSA slope for each participant was calculated, and the distributions of slopes were compared between the two groups. There was no significant difference in distributions of the slopes (P =.99). The two groups were identical in the proportions of participants with elevated PSA at each time point. There was no difference in the PSA slopes between the two groups (P =.34) and in the frequencies of elevated PSA values for those with elevated PSA at baseline. Incidence of prostate cancer during the 4 years was similar in the two groups (19 and 22 in the control and intervention arms, respectively).

CONCLUSION

Dietary intervention over a 4-year period with reduced fat and increased consumption of fruits, vegetables, and fiber has no impact on serum PSA levels in men. The study also offers no evidence that this dietary intervention over a 4-year period affects the incidence of prostate cancer during the 4 years.

Is the serum thyroglobulin response to recombinant human thyrotropin sufficient, by itself, to monitor for residual thyroid carcinoma?

The serum thyroglobulin (Tg) response to elevated TSH is one of the most sensitive indexes of residual thyroid carcinoma. We have explored the possibility that this test alone would be sufficient to detect residual thyroid carcinoma in thyroid cancer patients after total thyroidectomy and radioiodine remnant ablation. We used recombinant human TSH (rhTSH) to elevate serum TSH, rather than withdraw the patients from thyroid hormone. Routine evaluations, including diagnostic radioiodine whole body scans (DxWBS) and serum Tg, were performed on 366 patients after preparation by rhTSH, over a 2-yr interval. A retrospective analysis of the data from these patients revealed that 76% of those whose stimulated Tg rose to more than 2 microg/liter had evidence for residual thyroid carcinoma, whereas the same was true for only 13% of those whose stimulated Tg was 2 microg/liter or less. Using risk group stratification, we analyzed outcomes in a low risk subset (which excluded patients with elevated Tg levels on suppression, known metastatic disease, and clinical or histological evidence of aggressive disease). In this low risk group, we found that a stimulated Tg of 2 microg/liter or less had a 91.7% negative predictive value. No low risk patient who had had a prior negative DxWBS and a stimulated Tg of 2 microg/liter or less had any evidence of residual thyroid carcinoma. We conclude that the stimulated Tg alone is not sufficient by itself to screen unselected patients, but that it may be sufficient in low risk patients, especially those who have had a prior negative DxWBS.

Serum vascular endothelial growth factor levels are elevated in metastatic differentiated thyroid cancer but not increased by short-term TSH stimulation

Solid tumor formation requires the development of a blood supply adequate to meet the metabolic demands of the enlarging tumor mass that cannot be sustained by simple diffusion. One principal stimulant to endothelial cell growth and migration, vascular endothelial growth factor (VEGF), is synthesized and secreted by thyroid cancer cells. Furthermore, VEGF overexpression is associated with an aggressive thyroid cancer phenotype in both animal models and clinical-pathological studies. In other malignancies, elevated serum levels of VEGF often correlate with stage of disease and other poor prognostic clinical features. Therefore, we hypothesized that serum VEGF levels would be significantly higher in patients with persistent or recurrent thyroid cancer than in those cured of the disease. Because TSH stimulates both normal and neoplastic thyroid cells, we also proposed that serum VEGF would be further increased by TSH stimulation. Sixty-nine patients with either papillary or follicular thyroid cancer, status post total thyroidectomy, and prior radioactive iodine ablation, who had undergone routine recombinant human TSH (rhTSH, Thyrogen, Genzyme Transgenics Corp., Cambridge, MA) assisted whole-body radioactive iodine scanning, were included in this study. This cohort (mean age 53 +/- 16 yr, 51% female) included 21 patients with no evidence of disease and 48 patients with local or distant metastases. Stored serum samples obtained for standard Tg determinations before and 72 h following standard rhTSH stimulation were identified and assayed for VEGF 165 (R \[amp ]\ D Systems, Minneapolis, MN). Baseline serum VEGF levels obtained at a time of TSH suppression were significantly higher in patients with known metastatic disease than in those with no evidence of disease (416 +/- 62 pg/ml vs. 185 +/- 25 pg/ml, P = 0.001). Patients with distant metastases had baseline serum VEGF levels that did not differ significantly from patients with only cervical recurrences (455 +/- 90 pg/ml in distant metastases vs. 330 +/- 44 pg/ml for local cervical recurrences). Short-term TSH stimulation, although causing a significant rise in serum Tg, resulted in no significant increase in serum VEGF measured 72 h after rhTSH injection in either the patients with known metastatic disease (416 +/- 62 pg/ml baseline vs. 419 +/- 71 pg/ml after TSH stimulation) or in cured patients (185 +/- 25 pg/ml baseline vs. 191 +/- 33 pg/ml after TSH stimulation). Subgroup analysis revealed that patients with metastatic disease arising from well differentiated primary thyroid cancers had significantly higher serum VEGF levels than patients with metastatic disease arising from poorly differentiated thyroid cancer primaries (485 +/- 74 pg/ml vs. 167 +/- 32 pg/ml, P = 0.003 by ANOVA). Poorly differentiated metastatic thyroid cancers had serum VEGF levels indistinguishable from patients cured of disease (167 +/- 32 pg/ml vs. 186 +/- 25 pg/ml). In summary, serum VEGF is significantly elevated in patients with metastatic differentiated thyroid cancer but not in those with poorly differentiated thyroid cancer metastases. No measurable increase in serum VEGF levels can be detected 72 h after short-term TSH stimulation with rhTSH. We conclude that serum VEGF may serve as a clinical useful marker of residual differentiated thyroid cancer.

Radioiodine ablation of thyroid remnants after preparation with recombinant human thyrotropin

Radioiodine ablation (RA) of normal thyroid remnants after thyroidectomy for differentiated thyroid carcinoma improves the sensitivity of subsequent radioiodine scans and serum thyroglobulin measurements for detection of residual thyroid carcinoma. Local cancer recurrences are also lower after RA. One standard preparation for RA involves rendering the patient hypothyroid in order to stimulate endogenous thyrotropin (TSH) secretion and sodium iodide symporter (NIS) activity. An alternative approach is to prescribe thyroxine after thyroidectomy and to stimulate NIS with exogenous recombinant human thyrotropin (rhTSH). This latter approach was used in 10 patients at our medical center. Complete resolution of all visible 131I thyroid bed uptake was achieved in all when follow-up scans were performed 5 to 13 months later. This approach has the potential to successfully ablate thyroid remnants without the need to induce hypothyroidism.

Diltiazem Treatment Does Not Alter Renal Function After Thoracic Surgery

BACKGROUND

There are conflicting reports on the effects of diltiazem treatment on renal function in surgical patients. We sought to determine whether diltiazem treatment alters renal function in patients undergoing major thoracic surgery.

METHODS

In a prospective study, 330 patients scheduled for elective thoracic surgery received either IV diltiazem (n = 167) or placebo (n = 163) immediately after the operation and orally thereafter for 14 days in an effort to prevent postoperative atrial arrhythmias. Serum creatinine and BUN levels were compared before and during the first postoperative week.

RESULTS

Patients treated with diltiazem were similar to control subjects in terms of age (mean +/-SD, 66 +/- 10 years vs 67 +/- 10 years, respectively), baseline serum creatinine or BUN levels, prevalence of comorbid conditions, and surgical characteristics. During the first 5 postoperative days, the two groups did not differ in terms of serum creatinine or BUN levels. The incidence of renal failure was 0.6% in the diltiazem group and 1.2% in the placebo group (difference was not significant). There was no difference in the length of hospitalization or mortality rate.

CONCLUSIONS

In patients without renal disease who are undergoing elective thoracic surgery, prophylactic diltiazem treatment did not alter postoperative renal function.

Multicenter study of whole-blood creatinine, total carbon dioxide content, and chemistry profiling for laboratory and point-of-care testing in critical care in the United States

OBJECTIVES

To introduce a creatinine biosensor and a total carbon dioxide content (TCO2) method for whole-blood measurements, to evaluate the clinical performance of a new transportable analyzer that simultaneously performs these two and six other tests (Na+, K+, Cl-, glucose, urea nitrogen, and hematocrit), and to assess the potential of the new analyzer for point-of-care testing in critical care by comparing results obtained by nonlaboratory personnel and by medical technologists.

DESIGN

Multicenter sites compared whole-blood measurements with the transportable analyzer to plasma measurements from the same specimens with local reference instruments. One site compared whole-blood results produced by nonlaboratory personnel vs. medical technologists and evaluated day-to-day and within-day precision at the point of care.

SETTINGS AND PATIENTS

Four medical centers in the United States. Venous and arterial specimens from 710 critically ill patients with a variety of diagnoses. Point-of-care testing in the emergency room and operating room.

RESULTS

The linear regression analyses at the four medical centers showed the following: creatinine (a) slope, 0.91 to 1.22, (b) y intercept, -0.07 to 0.15 mg/dL, and (c) r2, 0.77 to 1.00; and TCO2: (a) slope, 0.64 to 1.00, (b) y intercept, 1.36 to 9.6 mmol/L, and (c) r2, 0.52 to 0.72 (yi, whole-blood analyses; xi, plasma reference measurements). Bland-Altman plots also were used to assess multicenter creatinine and TCO2 results. Of the other analytes, K+, glucose, and urea nitrogen had the highest r2-values. For the eight chemistry profile tests performed at the point of care (yi, nonlaboratory personnel results; xi, medical technologist results), the average value of r2 was 0.96 (SD 0.08) in the operating room and 0.96 (SD 0.06) in the emergency room, and mean paired differences (yi - xi) were not statistically or clinically significant. Precision was acceptable.

CONCLUSIONS

The performance of the creatinine biosensor and the TCO2 method was acceptable for whole-blood samples. Comparisons of whole-blood results from the transportable analyzer and plasma results from the local reference instruments revealed analyte biases that may be attributed to differences between direct whole-blood analyses and indirect-diluted plasma measurements and other factors. Performance of nonlaboratory personnel and medical technologists was equivalent for point-of-care testing in critical care settings. The whole-blood analyzer should be useful when patient care demands immediate results.

Genotype/phenotype relationships in HNF-4alpha/MODY1: haploinsufficiency is associated with reduced apolipoprotein (AII), apolipoprotein (CIII), lipoprotein(a), and triglyceride levels

Hepatocyte nuclear factor (HNF)-4alpha is a transcription factor that plays an important role in regulation of gene expression in pancreatic beta-cells and in the liver. Heterozygous mutations in the HNF-4alpha gene are responsible for maturity-onset diabetes of the young 1 (MODY1), which is characterized by pancreatic beta-cell-deficient insulin secretion. HNF-4alpha is a major transcriptional regulator of many genes expressed in the liver. However, no liver defect has been identified in individuals with HNF-4alpha mutations. In this study, we have identified HNF-4alpha target genes that are mainly expressed in the liver, including alpha1-antitrypsin, alpha1-antichymotrypsin, alpha-fetal protein, ceruloplasmin, IGF binding protein 1, transferrin, apolipoprotein(AI) [apo(AI)], apo(AII), apo(B), and apo(CIII). Serum levels of these proteins and Lp(a) and triglycerides were measured in 24 members of the HNF-4alpha/MODY1 RW pedigree (Q268X mutation), including 12 diabetic patients with HNF-4alpha mutations (D-HNF4+/-), 6 nondiabetic subjects with HNF-4alpha mutations (N-HNF4+/-), 6 normal relatives (N-HNF4+/+), 6 unrelated normal matched control subjects (N-HNF4+/+), and 12 matched diabetic (non-MODY1-5) patients (D-HNF4+/+). Serum levels of apo(AII), apo(CIII), lipoprotein(a) [Lp(a)], and triglyceride were significantly reduced in HNF4+/- subjects (26.9, 19.8, 12.1, and 72.1 mg/dl, respectively) compared with HNF4+/+ subjects (37.4, 26.5, 45.2, and 124.2 mg/dl, respectively) (P = 0.00001, P = 0.01, P = 0.00006, and P = 0.000003, respectively). This reduction was not found when apo(AII), apo(CIII), Lp(a), and triglyceride levels were compared in D-HNF4+/- versus N-HNF4+/- or in D-HNF4+/+ versus N-HNF4+/+ subjects, which indicates that HNF-4alpha haploinsufficiency rather than hyperglycemia is the primary cause of decreased serum protein and triglyceride concentrations. Furthermore, we determined that genetic or environmental modifiers other than HNF-4alpha do not appear to contribute to the observed decrease of HNF-4alpha-regulated serum proteins. This study demonstrates that a heterozygous HNF-4alpha mutation leads to an HNF-4alpha-dependent hepatocyte secretory defect of liver-specific proteins.

Perioperative alterations in plasma endothelin-1 and echocardiographic correlates of right heart function

OBJECTIVE

To determine whether greater changes in plasma endothelin-1 (ET-1) concentrations and right ventricular systolic pressure occur after major thoracic surgery than after major abdominal operations.

DESIGN

Prospective study.

SETTING

University hospital.

PARTICIPANTS

Patients undergoing elective thoracotomies (n = 12) or laparotomies (n = 10).

INTERVENTIONS

ET-1 was measured from blood obtained before anesthesia and again on postoperative days 1, 2, 3, and 5 (or 6). Transthoracic echocardiography was performed before surgery and on postoperative day 2 to evaluate right-sided heart function.

MEASUREMENTS AND MAIN RESULTS

After abdominal and thoracic surgery, systemic and estimated pulmonary vascular pressures were normal in both groups and unaffected by surgery. Plasma ET-1 concentrations decreased from baseline values during the first postoperative week with no differences between the groups.

CONCLUSIONS

In patients without organic heart disease, plasma ET-1 levels do not increase in response to major abdominal or thoracic surgery. Whether or not plasma ET-1 concentrations are elevated in patients developing clinically significant postoperative pulmonary hypertension requires further study.

Differential diagnosis of gammopathies by capillary electrophoresis and immunosubtraction: analysis of serum samples problematic by agarose gel electrophoresis

The capabilities of capillary electrophoresis (CE) for serum protein electrophoresis and immunotyping have been demonstrated. CE-based systems specifically designed for serum protein electrophoresis and immunotyping via immunosubtraction (IS) are now available and are being evaluated for efficiency, specificity and sensitivity by several groups. The use of CE for serum protein electrophoresis and immunotyping (IS) in the clinical laboratory compares well with agarose gel electrophoresis (AGE) and immunofixation (IF) for the detection and characterization of monoclonal proteins. In addition to routine use, this technology is useful for a subset of serum samples that are difficult to interpret with conventional technology. In this study, sera abnormalities difficult to detect/interpret by AGE-IF are subdivided into four categories: (i) patients with polyclonal increases in immunoglobulin, (ii) point of application artifacts, (iii) abnormalities in the beta region, and (iv) patients with free light chains. CE is superior to AGE for evaluating samples characterized by the above abnormalities. Sera containing monoclonal proteins within a polyclonal increase are easier to detect by CE as well as being easier to type by IS than by IF. Point-of-application artifacts, periodically observed with AGE, do not exist on CE since the point of detection is remote from the point of application. Enhanced resolution in the beta region allows for increased detection of monoclonal proteins migrating in this region. Some free light chains are undetected by CE as a result of no apparent abnormalities on the CE serum protein profile and, thus, still require IF for detection. CE detects more serum electrophoretic abnormalities than AGE in this clinically important group of patients with Bence Jones proteinemia.

Persistent alterations of the autonomic nervous system after noncardiac surgery

BACKGROUND. Changes in the sympathetic nervous system may be a cause of postoperative cardiovascular complications. The authors hypothesized that changes in both beta-adrenergic receptor (betaAR) function (as assessed in lymphocytes) and in sympathetic activity (assessed by plasma catecholamines and by heart rate variability [HRV] measurements obtained from Holter recordings) occur after operation.

METHODS

The HRV parameters were measured in 28 patients having thoracotomy (n = 14) or laparotomy (n = 14) before and for as long as 6 days after operation. Transthoracic echocardiography was performed before and on postoperative day 2. Lymphocytes were also isolated from blood obtained before anesthesia and again on postoperative days 1, 2, 3, and 5 (or 6). They were used to examine betaAR number (Bmax) and cyclic adenosine monophosphate (cAMP) production after stimulation with isoproterenol and prostaglandin E1. In addition, plasma epinephrine, norepinephrine, and cortisol concentrations were determined at similar intervals.

RESULTS

After abdominal and thoracic surgery, most time and all frequency indices of HRV decreased significantly, as did Bmax and basal and isoproterenol-stimulated cAMP production. The decrements in HRV correlated with those of Bmax and isoproterenol-stimulated cAMP throughout the first postoperative week and inversely correlated with the increase in heart rate. Plasma catecholamine concentrations did not change significantly from baseline values, but plasma cortisol levels did increase after operation in both groups. Left ventricular ejection fraction was normal in both groups and unaffected by surgery.

CONCLUSIONS

Persistent downregulation and desensitization of the lymphocyte betaAR/adenylyl cyclase system correlated with decrements in time and frequency domain indices of HRV throughout the first week after major abdominal or thoracic surgery. These physiologic alterations suggest the continued presence of adaptive autonomic regulatory mechanisms and may explain why the at-risk period after major surgery appears to be about 1 week or more.

Tumor cell reactivity mediated by IgM antibodies in sera from melanoma patients vaccinated with GM2 ganglioside covalently linked to KLH is increased by IgG antibodies

Natural IgM antibodies against the melanoma cell-surface ganglioside GM2, and IgM antibodies induced by vaccination with GM2 adherent to bacillus Calmette-Guerin, have been correlated with increased disease-free and overall survival in melanoma patients in previous phase I and II clinical trials. A vaccine containing GM2 covalently attached to keyhole limpet hemocyanin (KLH) plus the immunological adjuvant QS-21 now induces higher-titer, longer-lasting IgM antibodies against GM2 and has recently entered phase III clinical trials. For the first time this new vaccine also induces IgG antibodies against GM2 in the majority of immunized patients. With regard to immunity against bacteria, IgM antibodies have been described to be 1000-fold more effective than IgG antibodies at opsonification, complement-mediated cytotoxicity and protection from bacterial challenge. Though IgG antibodies have the theoretical advantage of being able to mediate antibody-directed cell-mediated cytotoxicity (ADCC), they may inhibit complement mediated IgM effector mechanisms against melanoma cells. Our goal was to confirm the functional characteristics of the anti-GM2 IgM and IgG antibodies induced by vaccination and to determine the impact that IgG antibodies might have on IgM antibody reactivity with GM2-positive tumor cells. Post-immunization sera from seven immunized patients were separated by size-exclusion chromatography into IgM and IgG fractions and a variety of serological assays were performed with the individual fractions and their combinations. Assays identifying specific IgM or IgG reactivity demonstrated partial inhibition by the opposite fraction. However, when the endpoint was complement-mediated lysis or overall antibody binding, which may more faithfully predict in vivo complement-mediated opsonification and lysis, the combinations of IgM and IgG fractions consistently demonstrated higher reactivity than either fraction alone. In addition, ADCC was induced in all seven patients. The results were the same whether the sera were obtained after 2 months or 2 years of immunizations. These findings suggest that IgG antibodies induced by the GM2-KLH plus QS-21 vaccine will not inhibit and should further augment the clinical impact of induced IgM antibodies.