Epithelial cells and their neighbors I. Role of intestinal myofibroblasts in development, repair, and cancer

Intestinal myofibroblasts are alpha-smooth muscle actin-positive stromal cells that exist as a syncytium with fibroblasts and mural cells in the lamina propria of the gut. Through expression and secretion of cytokines, chemokines, growth factors, prostaglandins, and basal lamina/extracellular matrix molecules, as well as expression of adhesion molecules and receptors for many of the same soluble factors and matrix, myofibroblasts mediate information flow between the epithelium and the mesenchymal elements of the lamina propria. With the use of these factors and receptors, they play a fundamental role in intestinal organogenesis and in the repair of wounding or disease. Intestinal neoplasms enlist and conscript myofibroblast factors and matrix molecules to promote neoplastic growth, carcinoma invasion, and distant metastases.

Class II MHC-expressing myofibroblasts play a role in the immunopathogenesis associated with staphylococcal enterotoxins

Food poisoning due to staphylococcal enterotoxins (SEs) affects hundreds of thousands of people each year. Little is known about how SEs initiate immune responses and cause pathogenesis. Here, we demonstrate that cultured human intestinal myofibroblasts (IMFs) bind SEs in an MHC class II-dependent fashion. IMFs respond to SE exposure with increased secretion of IL-6, IL-8, and TNF-alpha. A significant proliferative T cell response was observed when MHC class II-expressing IMFs were pulsed with SEA and cocultured with human CD4(+) T cells. In conclusion, our findings support the hypothesis that IMFs may play an important role in pathology associated with staphlococcocal enterotoxigenic disease.

Intestinal myofibroblasts and immune tolerance

Stromal cells, such as myofibroblasts and fibroblasts, represent a significant fraction of MHC class II-positive cells in the normal human colonic lamina propria, suggesting they may play an important role in CD4(+) T cell regulation in a tolerogenic environment. The aim of this study was to examine whether human colonic myofibroblasts (CMFs) phenotypically and functionally resemble conventional antigen-presenting cells (APCs). Our results support the hypothesis that intestinal myofibroblasts are a novel, nonprofessional APC phenotype important in modulating mucosal T cell responses. Given their strategic location, we propose that intestinal myofibroblasts play a critical role in mediating tolerance to luminal antigens.

Myelophthisis as a solitary manifestation of failure from rectal carcinoma. A Batson phenomenon?

Rectal carcinoma is uncommonly associated with systemic metastases in the absence of liver metastases, reflecting the predilection for spread via the portal system. Occasionally, isolated lung metastases are seen, which are usually attributed to spread via the portosystemic anastomoses in the distal rectum. However, myelophthisis is an unreported complication of rectal cancer as an isolated form of systemic failure. We present a case of fatal myelophthisis associated with otherwise localized rectal carcinoma secondary to metastatic rectal cancer. This observation led to the hypothesis that spread to the bone marrow occurred via a "third circulation," the Batson plexus, a network of deep pelvic veins with rich anastomoses to the vertebral plexus.

Pyogenic spondylodiskitis: a radiologic/pathologic and culture correlation study

BACKGROUND

Intervertebral disk tissue is resistant to hematogenous infection because of its avascularity. However, spondylodiskitis is being diagnosed with increasing frequency because of advancement in magnetic resonance imaging technology. There is a dearth of information regarding the bacteriology, histomorphologic features, and radiopathologic correlation of spondylodiskitis.

DESIGN

The study population consisted of 20 patients diagnosed as having spondylodiskitis by magnetic resonance imaging with and without gadolinium 67 enhancement and bone scans with technetium Tc 99m or gallium citrate Ga 67. Twenty-seven biopsy and debridement specimens were obtained from these patients. The specimens were cultured for microorganisms and also processed for histopathologic testing. Tissue sections were examined with hematoxylin-eosin and stains for infectious agents (Gomori's methenamine-silver, Gram, and Ziehl-Neelsen stains).

RESULTS

Where intervertebral disk tissue was present (23 of 27 cases), the morphologic changes included vascularization (with or without granulation tissue), myxoid degeneration, and necrosis. Chronic osteomyelitis was present in all 27 specimens and was associated with acute osteomyelitis in 7 cases (25%). Twenty-one of 27 cases had positive culture results (mostly pyogenic bacteria), but special stains revealed microorganisms in sections of the disk in only 4 cases (3 cases with gram-positive cocci and 1 with yeast consistent with Blastomyces). Florid acute inflammation was present in all the 4 cases.

CONCLUSION

Histopathologic features of acute spondylodiskitis include vascular proliferation, myxoid degeneration, and necrosis of the disk tissue with adjacent chronic osteomyelitis. Acute inflammation is variable and when florid is usually associated with identifiable organisms on histologic examination. At biopsy, tissue should be submitted for culture, since culture has a high sensitivity and specificity for detecting the etiologic organism.

Acrometastasis in renal cell carcinoma

Acrometastasis is rare and may occur as the primary manifestation of an occult malignant tumor. Clinically, it may mimic benign osteoarthritic diseases, thus resulting in misdiagnosis and improper treatment. We describe a patient with renal cell carcinoma that presented itself as a case of chronic osteomyelitis after trauma to a finger. Such a lesion presents diagnostic challenges to both clinicians and histopathologists.

Tubulovillous adenoma of the urinary bladder

We report a case of vesical tubulovillous adenoma that occurred in a background of protracted chronic cystitis with intestinal-type glandular metaplasia and extensive cellular atypia (dysplasia) in the flat mucosa. Flow cytometry analysis showed DNA aneuploidy in the adenoma. Increased expression of the tumor suppresser gene, p53, and also of cellular proliferation markers (proliferating cell nuclear antigen and MIB-1) were detected in the villous adenoma and in the dysplastic regions of the flat metaplastic mucosa. These findings provide insight into the biology of intestinal metaplasia and also lend support to the theory of the chronic irritation-metaplasia-dysplasia-carcinoma sequence.

Testicular "tumor" of the adrenogenital syndrome: a case report of an unusual association with myelolipoma and seminoma in cryptorchidism

BACKGROUND

Males with congenital adrenal hyperplasia may develop bilateral testicular masses in early adult life. These are not malignant and generally regress with corticosteroid therapy. The authors report a case occurring in a 44-year-old man with associated seminoma and myelolipoma in an undescended testis.

METHODS

The testicular tumors were analyzed by histologic, flow cytometric, and ultrastructural techniques.

RESULTS

The tumors in both testes were comprised of polygonal cells with abundant granular eosinophilic cytoplasm, occasionally with brown (lipochrome) pigment and round nuclei of various sizes with prominent nucleoli. These cells were grouped into nodules by dense and sometimes thick fibrous trabeculae in the right testis. The areas corresponding to the fibrous trabeculae in the left (intraabdominal) testis were replaced by mixture of hematopoietic (myeloid) and fatty tissue in various proportions characteristic of myelolipoma. The left testis also had a well demarcated tumor that was diagnostic of seminoma. Electron microscopy demonstrated abundant smooth endoplasmic reticulum, a moderate number of mitochondria with tubulovesicular cristae, lipid droplets, and lipofuscin granules in the polygonal cells. No Reinke's crystals were observed. The patient received corticosteroids for his adrenocorticoid deficiency and also underwent external beam irradiation to the retroperitoneum for seminoma.

CONCLUSIONS

This case illustrates an unusual presentation of a testicular tumor in a patient with the adrenogenital syndrome as well as with myelolipoma and seminoma in a cryptorchid testis. The possibility of an associated neoplasm that could be potentially fatal should be considered whenever a testicular tumor of the adrenogenital syndrome continues to grow despite adequate hormonal treatment.

Sensitivity and specificity of triphenyl tetrazolium chloride in the gross diagnosis of acute myocardial infarcts

OBJECTIVE

Myocardial infarction is the most common cause of sudden death in the United States. However, the identification of early myocardial infarcts at necropsy is frequently difficult, since unequivocal gross changes of infarcts do not become apparent for 24 to 48 hours following myocardial ischemic injury. The use of dyes, such as nitro-blue tetrazolium and 2,3,5 triphenyl tetrazolium chloride (TTC), that identify the dehydrogenase-deficient infarcted myocardium has been shown, largely by animal studies, to be very helpful in the macroscopic diagnosis of such cases. Such animal studies could not be directly extrapolated to human autopsy studies, however, because of the assumption that autolysis may invalidate the histochemical assessment of myocardial enzymatic changes after death. This study was carried out to evaluate the sensitivity and specificity of TTC in the gross diagnosis of acute myocardial infarction in the human population.

DESIGN

The TTC stain reactions were correlated with histologic findings in the hearts of 638 consecutive adult autopsies.

RESULTS

Of the 638 hearts examined by TTC, 174 hearts stained positive for acute infarction; histology confirmed myocardial infarction in 140 hearts. Histologic examination revealed acute infarcts in 41 of the remaining 464 cases that had stained negatively with TTC. The use of TTC in the macroscopic diagnosis of acute myocardial infarcts in the human population was found to have a diagnostic sensitivity of 77.4% and a specificity of 92.6%. The predictive value of a positive test was 80.5%, and that of a negative test was 91.2%.

CONCLUSIONS

The overall diagnostic efficiency of the TTC test (ie, number of patients correctly identified) was 88%. These results show that the TTC test is a reliable, sensitive, and specific adjunct in the examination of the human heart at necropsy.

Recurrent massive hemothorax in Rendu-Osler-Weber syndrome

We report a case of Rendu-Osler-Weber syndrome, occurring as sudden death after two episodes of massive hemothorax. Autopsy revealed massive hemothorax resulting from spontaneous rupture of one of three subpleural arteriovenous malformations. Review of the patient's hospital records showed that she had had a massive spontaneous hemothorax 13 years earlier that was managed conservatively. This case emphasizes the importance of early therapeutic (surgical or radiologic) intervention in the treatment of pulmonary arteriovenous malformations.

Arterial bullet embolism resulting in delayed vascular insufficiency: a rationale for mandatory extraction

This paper reports a case of migrating intravascular bullet embolus that initially produced no symptoms but resulted in an above-knee amputation 14 months after its entry into a peripheral artery. The missile entered through a penetrating gunshot wound to the abdominal aorta and later became lodged in the left popliteal artery. However, the bullet fragment migrated further into the posterior tibial artery with consequent vascular insufficiency requiring a supracondylar amputation of the left lower extremity 14 months later. Emphasis is placed on the need for a high index of suspicion for bullet embolism, aggressive search for any bullets unaccounted for, and early surgical removal of all confirmed arterial emboli.

Intracellular calcium and hydrogen ions in diabetes mellitus

Diabetes mellitus is a multi-component syndrome that is often complicated by angiopathy which is partly due to enhanced platelet functions. Using fluorescent dyes 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein (BCECF) and Fura-2 AM, changes was evaluated in the concentration of baseline and thrombin-stimulated increases in intracellular ionized calcium (Ca2+i) relative to hydrogen ions in the platelets from control, insulin-treated, and non-treated diabetic rats. The cytosol of platelets from the diabetic rats were more acidic compared to the insulin-treated and normal control rats. The increased intracellular hydrogen ion concentration [H+] or decreased pH (pH) in the diabetic rat platelets is associated with an increased baseline [Ca2+]i. Upon stimulation with thrombin, the mean peak [Ca2+]i for the insulin-treated (309 +/- 97 nmol/L) and untreated (339 +/- 135 nmol/L) diabetic rats was significantly higher than the concentration for the normal rats (213 +/- 101 nmol/L). Treatment with insulin attempts to correct the diabetes-induced elevation in the baseline of [Ca2+]i and intracellular H+. These results suggest that the relationships between Ca2+ and H+ relative to binding sites are similar in the intra- and extracellular compartments. It is our conclusion that the enhanced platelet activity and associated development of vascular diseases in diabetes may be due to an increased intracellular H+ that caused an increased baseline [Ca2+]i in diabetes mellitus.

Intracellular ionized calcium and increasing doses of lithium chloride therapy in healthy Sprague-Dawley rats

The use of lithium salts in the prophylaxis and treatment of several psychiatric and neurologic disorders continues to be well accepted despite the apparent lack of understanding regarding its mode of action at the molecular level. This lack of delineation in the mechanism of action is supported by numerous conflicting publications. Despite the lack of understanding, a role for calcium in the manifestation of lithium's action is a constant singular consensus. Intracellular ionized calcium ([Ca2++]i) is involved in the proper functioning of cells because of its role in the second messenger pathway. It is therefore essential to evaluate the effect of lithium on intracellular calcium metabolism in a well-defined system. In this study, platelets loaded with Fura-2-Acetoxymethyl were used to evaluate the effect of intraperitoneally administered lithium chloride at 0, 2.5, 5.0, 7.5, and 10 mmol/kg body wt. on [Ca++]i. The results showed a slight relative increase in serum Ca++ that correlated well with the dose of LiCl administered to the rats. The baseline [Ca++]i were comparable in the study groups, but the response to thrombin stimulation was more pronounced at LiCl doses of 2.5, 5.0, and 7.5/kg body wt. compared with control and rats treated with 10 mmol LiCl/kg body wt. This finding suggests a dose-dependent response of [Ca++]i to LiCl treatment. The observation may therefore explain the variations that have been reported in [Ca++]i studies with respect to LiCl therapy using different doses.