An improved method for estimating the heart-to-mediastinum ratio from cardiac sympathetic nerve imaging with low-energy high-resolution collimators

Background

Septal penetration causes underestimation of the heart-to-mediastinum (H/M) ratio in cardiac ¹²³I-metaiodobenzylguanidine (MIBG) imaging with a low-energy high-resolution (LEHR) collimator. We aimed to improve the method of estimating the H/M ratios using the LEHR collimator.

Methods and Results

4 hours after ¹²³I-MIBG injection, 40 patients were imaged successively with the medium-energy (ME) and LEHR collimators using gamma cameras having 3/8-inch crystals. Severe underestimation of the H/M ratios was observed with the LEHR collimator when compared to the ME collimator. Narrowing the energy window width did not reduce the underestimation. Application of ¹²³I-dual-window (IDW) correction using a narrow or wide subwindow reduced the underestimation substantially but not entirely. The H/M ratios estimated from the LEHR images with or without IDW correction were corrected based on their correlations with the ratios estimated from the ME images. This empiric correction removed systematic underestimation, and residual errors were reduced when the H/M ratios after IDW correction were converted using the empiric equation. The conversion equation was successfully applied to the correction of the H/M ratios determined in another 40 patients using a 5/8-inch crystal.

Conclusions

In estimating the H/M ratios using an LEHR collimator, empiric correction combined with IDW correction improves concordance with ME-based values in comparison with empiric correction alone.     

Energy metabolism and turnover are increased in mice lacking the cholecystokinin-B receptor

Cholecystokinin (CCK) is an important gastrointestinal hormone as well as a neurotransmitter. Two types of CCK receptors, types A and B, have been identified. The CCK-A receptor is involved in satiety, food intake and behavior, whereas the B receptor is involved in anxiety. We recently produced CCK-A, -B and AB receptor knockout mice to study the role of these receptors in energy metabolism. Daily energy intake and expenditure were significantly greater in CCK-BR(-/-) and CCK-AR(-/-)BR(-/-) mice than CCK-AR(-/-) and wild-type [CCK-AR(+/+)BR(+/+)] mice. Relative liver and kidney weights (g/kg body) were significantly greater in CCK-AR(-/-)BR(-/-) mice than in wild-type mice. Energy metabolism and energy turnover were increased in mice with a disruption of the CCK-BR gene, although the underlying mechanism is unknown.     

Significance of venous thromboembolism in women with uterine carcinosarcoma

Objective

To identify risk factors for venous thromboembolism (VTE) and to examine the association of VTE and survival in women with uterine carcinosarcoma.

Pathological Aspects of Radiofrequency Catheter Ablation of the Canine Atrioventricular Node and Bundle of His

Radiofrequency catheter ablation of the atrioventricular (AV) node or bundle of His was performed in 12 adult mongrel dogs. The aim was to create chronic incomplete AV block (first- and second-degree AV block) and to examine the histopathology of the ablated lesions. However, the late electrophysiological results (2 4 weeks follow up) were various: normal in 2 dogs, mild PR prolongation (< 50%) in 2 dogs, first-degree AV block (PR prolongation a 50%) in 2 dogs, second degree AV block in 2 dogs, complete AV block in 4 dogs. The maximally ablated area (%) of the atrioventricular conduction system in serial histologic sections from dogs with these conditions was 69%, 75%, 89.5%, 95% and 99.5%, respectively. The number of intact conduction cells at the maximally ablated site varied from 6 to 30 in the four cases of incomplete AV block. The mean ablated volume (%) of either the AV node or penetrating His bundle correlated roughly with the degree of AV block. The ablated lesions were well demarcated and almost replaced by dense fibrous tissue at 4 weeks. Interruption (3 dogs) or thinning (1 dog) of the endocardial elastic lamellae was detected, in association with endocardial thickening (mean 913 μm). Endocardial thrombi were found in 3 dogs (2 fresh, 1 organized). We conclude that radiofrequency catheter ablation does not cause severe complicated lesions. Several possible conditions for creating chronic incomplete AV block are discussed. Acta Pathol Jpn 41: 487–498, 1991.     

Expression of HGF and IGF-1 during regeneration of masseter muscle in <Emphasis Type="Italic">mdx</Emphasis> mice

This study investigated the expression of the growth factors HGF and IGF-1 during the process of muscle regeneration in mdx mice. HGF and IGF-1 are reportedly expressed during the regeneration of muscle tissue in vitro. However, few studies have focused on the role of HGF and IGF-1 during muscle regeneration in mdx mice, which lack expression of the dystrophin gene. In the present study, we examined the expression of HGF and IGF-1 in masseter muscle during muscle regeneration in mdx and B10 (control) mice using histological analysis, immunohistochemistry and Western blotting, as well as examining gene expression by RT-PCR, at 3, 4 and 9 weeks. Mdx mice showed localized HGF and IGF-1 positivity in the cytoplasm of regenerating muscle cells at 3 and 4 weeks, but hardly any reactivity was evident at 9 weeks. The control group was completely negative for IGF-1 at any of the examined time points. Western blotting showed stronger expression of HGF and IGF-1 in mdx mice than in B10 mice at 3 and 4 weeks, but at 9 weeks the expression was absent in both groups. Similar results were obtained using RT-PCR. These present results suggest that HGF and IGF-1 appear to play an important role during regeneration of the masseter muscle in mdx mice.     

Pericellular deposition of basement membrane material in myxoid meningioma: Immunohistochemical evidence for unbalanced production of type IV collagen and laminin

Myxold meningioma seen In a 25-year-old man is presented. Hlstologlcally, Leu 7-positive meningotheliomatous tumor cells were embedded in the alclanophilic myxoid matrix. Characteristically, eosinophilic granular deposition was detected around the tumor cells and the boundary of tumor cells was not clearly defined. The pericellular deposits revealed the nature of the basement membrane with positive reactions by periodic acid-Schlff (PAS) sequence and immunostaining for type IV collagen, which is the major structural component of basement membrane. However, laminin, which is a non-collagenous glycoprotein of the basement membrane, was undetectable, and silver was not impregnated. Similar abnormal deposition of PAS-positive basement membrane-like material was observed in the myxoid stroma of a microcystic meningioma among 72 meninglomas additionally examined. The significance of the discrepant localization of immunoreactive type IV collagen and laminin is discussed.     

Immune aspects of intestinal metaplasia of the stomach: An immunohistochemical study

Summary Immune characteristics of intestinal metaplasia of the stomach were analyzed by the immunoperoxidase technique in frozen and paraffin-embedded specimens. In fetal and minimally inflamed adult gastric mucosa, secretory component (SC) was absent from epithelial cells. Non-intestinalized gastric mucosa with evident inflammatory changes showed weak SC immunoreactivity at the generative cell zone. Enhanced immunoreactivity of SC with evidence of transepithelial transport of IgA and IgM, but not of IgG, was demonstrated in intestinalized glands of either the complete or incomplete type. The number of inflammatory cells and lymphoid follicles was decreased in intestinalized mucosa when compared with that in non-intestinalized gastritic mucosa; J chain-negative IgG plasma cells and T cells, both of which were fairly abundant in the latter mucosa, were remarkably decreased in the former mucosa, whereas the decrease of J chain-positive IgA or IgM plasma cells was slight or equivocal. In either mucosa, IgA was the most popular immunoglobulin class in plasma cells. IgD plasma cells were very rare. In the germinal centers of lymphoid follicles which were preferentially distributed in non-intestinalized gastritic mucosa, IgM or IgG germinocytes predominated over IgA germinocytes, and a few T cells and NK cells also were present. Intraepithelial lymphoid cells with a T-suppressor phenotype were detected in intestinalized glands. The possibility that intestinal metaplasia is an adaptation to long-standing chronic gastritis is discussed.     

SECRETORY GRANULES IN BENIGN AND MALIGNANT GLUCAGONOMAS OF THE PANCREAS

Two cases of glucagonoma, one benign and the other malignant, were presented. Benign glucagonoma in a 29-year old man with multiple endocrine neoplasia type 1 was composed largely of tumor cells with secretory granules ranging from 139 to 417 nm in diameter identical to A cell granules. There were a few tumor cells which contained no A cell granules but smaller granules of approximately 166 nm diameter similar to those of pancreatic polypeptide-containing cells. Radioimmunoassay of the tumor extract showed 319 μg/g wet weight of glucagon and 0.72 μg/g wet weight of pancreatic polypeptide. Malignant glucagonoma in a 34 year-old man was a massive tumor of 7x6x5 cm replacing the tail and body of the pancreas with multiple metastases. The tumor contained 0.2 μg/g wet weight of glucagon and 0.065, ug g wet weight of vasoactive intestinal peptide. The electron microscopic examination revealed that the tumor cells had variable numbers of atypical secretory granules measuring 110 to 200 nm in diameter different from A cell granules. An analysis of plasma glucagon by the gel filtration technique showed the heterogeneity of glucagon molecules indicating the presence of large glucagon. Atypical secretory granules in malignant glucagonoma were considered to represent immature granules containing the precursor or intermediate of glucagon.