Evaluation of phagocytic function of macrophages in rats after partial splenectomy.

BACKGROUND: Understanding the immunologic properties of the spleen has enabled surgeons to practice splenic conservation surgery. If the upper pole of the spleen can be preserved solely on the upper short gastric vessels, will phagocytic function of macrophages in remnant splenic tissue be affected? The aim of this experimental study was to evaluate the phagocytic function of macrophages in partially resected spleens, with hilar excision preserving the short gastric vessels. STUDY DESIGN: Forty-eight female Wistar albino rats were divided into four groups. Groups 1 and 2 underwent sham operations and groups 3 and 4 underwent partial splenectomy. One milliliter of sodium chloride 0.9% was injected into the abdomen of the rats in groups 1 and 3 and 1 mL of Streptococcus pneumoniae type III as an antigenic stimulus was injected into the abdomen of the rats in groups 2 and 4, 6 weeks after the first operation. Forty-eight hours later, relaparotomy was performed in all animals. India ink was used to determine the capacity of uptake in the splenic phagocytes. To evaluate the phagocytic function of the splenic tissues, histologic examinations were performed according to a macrophage grading system. RESULTS: All spleens in all four groups were stained black after injection of India ink. Phagocytic activity of macrophages was reduced in the partially splenectomized groups, compared with intact spleen groups (group 3 versus group 1; p < 0.0001, group 4 versus group 2; p < 0.0001). There was a significant difference between groups 1 and 2 according to phagocytic function of macrophages (p = 0.0121). Also, after Streptococcus pneumoniae type III injection as an antigenic stimulus in group 4, we found that the phagocytic functions of macrophages increased compared with those of the sodium chloride 0.9%-injected group 3 after partial splenectomy (p < 0.0001). CONCLUSIONS: Phagocytic function of macrophages in rats decreased after partial splenectomy. Nevertheless, the remnant spleens in rats could be stimulated when challenged with an antigenic stimulus.

Immune function of the upper splenic remnant supplied by short gastric vessels.

OBJECTIVE: To study the immune function of the upper third of the spleen supplied by short gastric vessels after two thirds partial splenectomy. DESIGN: Experimental study. SETTING: Teaching hospital, Turkey. MATERIAL: Sixty Wistar-albino rats, 20 in each group. INTERVENTIONS: Control = sham laparotomy; partial splenectomy = the upper third of the spleen supplied by short gastric vessels was preserved after two thirds partial splenectomy and dividing the main vascular supply; and total splenectomy. At the end of the sixth week postoperatively, antigenic stimulation was induced with an injection of pneumococcal suspension in 10 animals from each group. 0.5 ml of diluted Indian ink was injected into the aorta. MAIN OUTCOME MEASURES: Histological architecture of splenic tissue, and changes in the white pulp after antigenic stimulus. Bacteriological analysis with aerobic blood culture. Phagocytic activity as counted by Indian-ink-laden macrophages. The ability to produce antibodies as measured by serum IgM concentrations. RESULTS: Histological architecture of splenic tissue was normal. Germinal centres (p = 0.02), lymphoid follicles (p = 0.09), and their ratio (p = 0.0006) in the white pulp of the splenic remnant was significantly increased after antigenic stimulus compared with normal spleen. Significantly more animals without spleens developed bacteraemia (p = 0.02). Phagocytic activity of the upper splenic remnant was 89% that of normal spleen. Serum IgM concentrations without antigenic stimulus were 144, 138.2 (p = 0.6), and 86.2 (p < 0.001) mg/L; and with antigenic stimulus 263, 201.7 (p < 0.0001), and 98.1 (p < 0.0001) mg/L in groups 1, 2, and 3, respectively. The increase in serum IgM concentrations as a response to antigen was significant in the control (p < 0.0001) and in the partial splenectomy group (p < 0.0001), but not in the splenectomy group (p = 0.1). CONCLUSIONS: After reduction of its volume, the upper splenic remnant remained adequately supplied by the short gastric vessels. The upper part of the spleen preserved its normal histological architecture, had considerable phagocytic activity, possessed the ability to produce antibodies, and created a satisfactory immune response to antigenic stimulus. In rats, a considerable volume of functional and well perfused splenic tissue is preserved even after dividing the main vessels.

Mucinous tumors of the ovary: interobserver diagnostic variability and utility of sectioning protocols.

OBJECTIVES: To determine the interobserver variability of the subclassification of ovarian mucinous tumors and the utility of different sectioning protocols. METHODS: Six pathologists retrospectively reclassified 73 mucinous tumors (30 adenomas, 22 low malignant potential tumors, and 21 carcinomas). Using probabilities, the accuracy of limited sectioning protocols was compared with that of a one section per centimeter protocol. RESULTS: The mean kappa statistic was 0.56, indicating only good agreement. Although a limited sectioning protocol would result in misdiagnosing cases of stage IA carcinoma as a low malignant potential tumor, the overall prognosis of patients with low malignant potential tumors would not markedly change. The prognosis of a patient with a low malignant potential tumor using limited sectioning was within the prognostic range owing to interobserver variability alone. CONCLUSIONS: We conclude that extensive sectioning of ovarian mucinous tumors has limited benefit.

Prognostic implications of extracapsular extension of lymph node metastases in prostate cancer.

We performed a retrospective review of surgical pathology specimens and clinical data for all patients with node-positive prostate cancer diagnosed in our institutions between 1985 and 1994. We used adjusted actuarial survival analyses and univariate and multivariate analyses to evaluate the clinical significance of extracapsular perinodal tumor extension. Sixty patients with histologically confirmed prostate cancer metastatic to regional lymph nodes were reviewed. Forty-two patients (70%) had evidence of extracapsular extension of the tumor into perinodal tissue. The 5-year adjusted cumulative survival rates for patients with extracapsular nodal extension was 54.6%, compared with 71.4% for patients with histologically confined nodal metastases (P < .05). Univariate and multivariate analyses revealed the presence of extracapsular nodal tumor extension to be an independent predictor of patient survival. In this study, only the histologic grade (Gleason score) of the primary tumor was a stronger predictive factor. These data suggest that histologic evidence of extracapsular tumor extension from lymph node metastases into perinodal tissue might be an important prognostic factor in patients with node-positive adenocarcinoma of the prostate. Development of a pathologic substage to include this feature might be warranted.

Low-grade transitional cell carcinoma of the urinary bladder: application of select cytologic criteria to improve diagnostic accuracy [corrected].

The cytologic diagnosis of low-grade transitional cell carcinoma of the bladder is difficult, and the reported sensitivity of a positive diagnosis ranges from 0 to 73%. Using regression analysis, our laboratory previously reported the criteria of increased nuclear/cytoplasmic ratios, irregular nuclear membranes, and cytoplasmic homogeneity as indicative of low-grade transitional cell carcinoma. To examine the validity of these criteria, six observers examined 88 bladder-wash specimens (39 transitional cell carcinomas and 49 benign) and, using the selected criteria, graded each wash for the probability of malignancy. Diagnostic accuracy was measured using the receiver operating characteristic curve and the likelihood ratio. Overall observer accuracy was 76%, the sensitivity of a definitive negative diagnosis was 82%, and the specificity of a definitive positive diagnosis was 96%. We conclude that key cytologic criteria can be learned and effectively applied with high accuracy. Observer variation in diagnostic categories might reflect different confidence levels and probabilities of transitional cell carcinoma.