Modulation of the development of bleomycin-induced fibrosis by deferoxamine

Bleomycin is an antineoplastic compound which produces a time- and dose-dependent pulmonary fibrosis. The mechanisms which cause this fibrosis are not known. The ability of bleomycin to produce oxygen radicals in the presence of iron and molecular oxygen appears to be related to the fibrosis. Previous studies, which have examined single time points utilizing the ferric ion chelator deferoxamine and iron-deficient diets, suggest that iron plays a central role in bleomycin-induced pulmonary fibrosis. Therefore, the present study was designed to determine the effects of deferoxamine on the development of bleomycin-induced pulmonary fibrosis. Deferoxamine pretreatment and daily injections resulted in a significant reduction in lung collagen content and lung lipid peroxidation 21 days after intratracheal bleomycin compared with bleomycin treatment alone. In addition deferoxamine treatment significantly inhibited lung DNA increases at 4, 7, and 14 days after bleomycin treatment compared with bleomycin treatment alone. These data indicate that deferoxamine treatment reduces the development of bleomycin-induced pulmonary fibrosis in the later phase. The mechanism might be by the prevention of iron-catalyzed, free-radical formation and modulation of some cellular functions.

Stability and electrophoretic characteristics of creatine kinase BB extracted from human brain and intestine

Creatine kinase (CK; EC 2.7.3.2) isoenzyme BB extracted from brains of rats reportedly undergoes modification at 37 degrees C, leaving an electrophoretic variant that accounts for most of the residual CK activity. This variant, called CK-BB', migrates on electrophoresis similarly to creatine kinase isoenzyme MB. Using electrophoresis and immunoinhibition with antiserum to creatine kinase isoenzyme MM, we found CK-BB to be the only identifiable cytoplasmic isoenzyme in surgical samples from human brain and intestine. In contrast, we found that some samples of brain obtained at autopsy contain CK-BB'. We also found that CK-BB extracted from human brain was converted to CK-BB' upon incubation in serum or plasma at 37 degrees C. We found a similar development of CK-BB' in incubation mixtures of serum or plasma containing CK-BB obtained from surgical samples of human intestine. The development of CK-BB' during infarction of the gastrointestinal system may thus be a source of false-positive CK-MB in the laboratory verification of myocardial infarction when electrophoresis is used as the only method to identify CK isoenzymes.

Stability and electrophoretic characteristics of creatine kinase BB extracted from human brain and intestine

Creatine kinase (CK; EC 2.7.3.2) isoenzyme BB extracted from brains of rats reportedly undergoes modification at 37 degrees C, leaving an electrophoretic variant that accounts for most of the residual CK activity. This variant, called CK-BB', migrates on electrophoresis similarly to creatine kinase isoenzyme MB. Using electrophoresis and immunoinhibition with antiserum to creatine kinase isoenzyme MM, we found CK-BB to be the only identifiable cytoplasmic isoenzyme in surgical samples from human brain and intestine. In contrast, we found that some samples of brain obtained at autopsy contain CK-BB'. We also found that CK-BB extracted from human brain was converted to CK-BB' upon incubation in serum or plasma at 37 degrees C. We found a similar development of CK-BB' in incubation mixtures of serum or plasma containing CK-BB obtained from surgical samples of human intestine. The development of CK-BB' during infarction of the gastrointestinal system may thus be a source of false-positive CK-MB in the laboratory verification of myocardial infarction when electrophoresis is used as the only method to identify CK isoenzymes.

Effect of iron deficiency on bleomycin-induced lung fibrosis in the hamster

Bleomycin produces a dose- and time-dependent interstitial pulmonary fibrosis in humans, and is widely used to produce an animal model for the study of interstitial pulmonary fibrosis. The mechanism(s) for bleomycin-induced pulmonary fibrosis is (are) unknown, but the production of oxygen radicals by a ferrous ion-molecular oxygen pathway might be related to the fibrosis. Therefore, we studied the effect of iron deficiency on the biochemical, inflammatory, and morphologic parameters of bleomycin-induced pulmonary fibrosis in the hamster. Mild iron deficiency was induced in hamsters by bleeding via the retro-orbital sinus and maintenance on an iron-deplete diet. After intratracheal administration of bleomycin (1 U), there was no accumulation of lung collagen in the iron-deficient bleomycin-treated animals. In comparison, iron-replete animals treated with bleomycin exhibited a significant (p less than 0.01) increase in lung collagen. In addition, bleomycin-treated iron-replete animals had increased lung lipid peroxidation (p less than 0.05), whereas bleomycin-treated iron-deficient animals did not (p greater than 0.05). Lung DNA and morphometric estimates of the lesion severity were significantly increased in both iron-replete and iron-deficient bleomycin-treated animals. These data indicate that iron deficiency is associated with a reduction in the severity of bleomycin-induced pulmonary fibrosis, possibly by the prevention of iron-catalyzed oxygen-radical formation and lipid peroxidation.

New developments in understanding phenytoin-induced gingival hyperplasia

In approximately half of the patients taking phenytoin, gingival fibroblasts proliferate, causing tissue overgrowth and gingival hyperplasia. Recent clinical and basic research is reviewed, describing the conditions associated with phenytoin therapy and gingival hyperplasia.

Detection of high incidence of K-ras oncogenes during human colon tumorigenesis

RNAse A mismatch cleavage analysis of 66 primary human colon tumors reveals a high incidence of K-ras genes with mutations at position 12. No apparent correlation was found between the presence of mutant oncogenes and the degree of invasiveness of the tumours but evidence for ras mutational activation in premalignant tissue was obtained.

Effect of temperature on argyrophil impregnation: development of a high temperature rapid argyrophil procedure

Our studies on the effects of temperature on the demonstration of neurosecretory granules using argyrophil stains indicate an inverse relationship between the time needed for staining and temperature of the silver and reducing solutions. Careful monitoring of the temperature of silver solutions during the Grimelius procedure and its modifications show long incubation times serve in large part only to bring the solutions to reaction temperature. Tissue sections added when this temperature has been reached will stain with the same intensity as sections impregnated for the entire incubation period. We have modified the argyrophil procedure so that double-impregnation with solutions preheated to 60-70 C and development in Bodian's reducer prepared with preheated water rapidly demonstrates secretory granules. Our method does not require a microwave oven and much shorter incubation periods are required than with usual procedures. It is not necessary to incubate sections in hot solutions for extended periods of time, which can lead to detachment of sections, nonspecific staining and decomposition of the silver solution. Rinsing after impregnation and before development greatly increases contrast of argyrophil cells by reducing background staining. Our procedure results in more reliable staining of argyrophil and argentaffin cells and takes only ten minutes.

Effects of dietary fats on bleomycin-induced pulmonary fibrosis

Bleomycin treatment has been used for the experimental induction of pulmonary fibrosis, but the mechanisms involved are poorly understood. Since alterations in the levels of certain fatty acid metabolites have been associated with bleomycin-induced lung injury, we examined the effects of different dietary fats on the development of bleomycin-induced pulmonary fibrosis. Weanling rats were raised on standard laboratory feed or a diet consisting of a fat-free powder to which was added either coconut oil or beef tallow (25% w/w). After 8 weeks of feeding, animals received either 1.5 units bleomycin or an equivalent volume of saline intratracheally. Bleomycin treatment resulted in significant increases in total lung hydroxyproline content in the groups fed the standard lab diet (p less than 0.001) and beef tallow diet (p less than 0.001), but not in the group receiving the coconut oil diet. Furthermore, the lung hydroxyproline content in bleomycin-treated animals was less with the beef tallow diet compared with standard lab feed (p less than 0.05). Bleomycin treatment resulted in an increase in thiobarbituric acid-reactive products, an index of lipid peroxidation, in lungs from animals fed the standard lab diet, but not in the other diet groups. The percentage of diseased lung, as determined by morphometric analysis, was increased in bleomycin-treated animals from all diet groups (p less than 0.05). We conclude that alterations in dietary fats can reduce the severity of pulmonary fibrosis resulting from bleomycin treatment. Possible mechanisms for this effect include alterations in eicosanoid metabolism or changes in immune or effector cell function.

A small adrenocortical carcinoma with aggressive behavior. An evaluation of criteria for malignancy

Adrenocortical carcinoma is an unusual tumor that tends to be larger than 100 g at diagnosis. Malignant adrenocortical tumors of less than 50 g have been reported rarely. We studied a small adrenocortical carcinoma that weighed 40 g and metastasized 3 1/2 years following bilateral adrenalectomy. The malignancy of adrenocortical tumors is frequently difficult to determine. Two recent studies have proposed histologic criteria for determining the malignancy of adrenal cortical tumors. Since the tumor we studied was initially judged to be benign, we sought to determine whether an extensive evaluation of this tumor using these recent criteria could have identified the tumor's potential for metastasizing. Careful application of these criteria indicated that the tumor was either a borderline lesion or a definitely malignant lesion. This emphasizes the need to approach systematically all adrenal neoplasms with regard to determining their malignant potential. Documenting small adrenocortical carcinomas also should help in setting criteria for evaluating adrenal masses discovered incidentally by sensitive radiologic methods.

Histologic variation in the skin lesions of the glucagonoma syndrome

Three cases of glucagonoma syndrome were seen in 1 year. Study of the skin biopsies from the first two cases led to a correct diagnosis from skin biopsy of the third case, although it was not suggested clinically. In each case serum glucagon levels were high and a pancreatic tumor was found, with complete remission of symptoms in cases 1 and 3 after resection; case 2 refused surgery and has died. A total of nine skin biopsies from the three patients showed a variety of findings: epidermal necrosis; subcorneal pustules, either isolated or associated with necrosis of the epidermis; confluent parakeratosis, epidermal hyperplasia, and marked papillary dermal angioplasia; and suppurative folliculitis. The clinical lesions in this syndrome vary from bright red macules to annular superficial erosions and flaccid pustules. Similarly, several histopathologic features of the disease can occur, which may represent the progression of the disease. No single histologic feature was specific for the disease, but a combination of the features is probably diagnostic. Therefore, multiple skin biopsies are recommended when this diagnosis is suspected.

Plasmacytoid T-cell lymphoma associated with chronic myeloproliferative disorder

This study reports the case of a patient who presented with evidence for a diagnosis of chronic myelogenous leukemia, as shown by blood and bone marrow analysis, and with generalized lymphadenopathy and splenomegaly. A lymph node biopsy revealed that the majority of the cells had plasmacytoid features but were consistently negative for surface or cytoplasmic immunoglobulin products, myelomonocytic surface markers, and peroxidase. Rather, lymph node plasmacytoid cells expressed T-cell markers (T 4/Leu 3+, T 10+), transferrin receptors (T 9+), and a proportion of them was also positive for sheep erythrocyte receptors (T 11/Leu 5+). This case is strikingly similar to a case reported by Lennert's group with respect to morphology, surface phenotypic features of the malignant plasmacytoid cells, and the association between a lymphoproliferative and a myeloproliferative disorder. This association suggests that plasmacytoid T-cells might exert a regulatory role on proliferation of myeloid cells.

Cushing's syndrome. Screening methods in hospitalized patients

We studied 18 patients with Cushing's syndrome and 25 patients in which Cushing's syndrome was excluded on follow-up to evaluate screening tests for Cushing's syndrome in hospitalized patients. Plasma cortisol values (at 8 AM) were found least helpful yielding 29% false-positive and 60% false-negative values. Diurnal variation of cortisol was present in 30% of patients with Cushing's syndrome and absent in 18% of patients without Cushing's syndrome. When corrected for total urinary creatinine, 24-hour urinary 17-hydroxycorticosteroids were specific (all patients without Cushing's syndrome had normal values) but not very sensitive (two of 12 patients with Cushing's syndrome had normal values). Similarly, 24-hour 17-ketosteroids were of little help with 17% false-positive and 35% false-negative values. Twenty-four-hour urinary free cortisol was both a sensitive and specific screening test for Cushing's syndrome (no false-positive and no false-negative results). We conclude that urinary free cortisol is the most efficient screening method for Cushing's syndrome in hospitalized patients.

Corticotropin production by tumors of the autonomic nervous system

Cushing's syndrome in association with a tumor of the autonomic nervous system (ANS) has been reported occasionally. We studied a patient who had an intra-adrenal paraganglioma (pheochromocytoma), and whose plasma corticotropin level was elevated prior to surgery but dropped to a low value following removal of the tumor. Catecholamine levels were elevated preoperatively and catecholamines were extracted from the tumor tissue. Corticotropin was identified in the tumor by immunoperoxidase staining. We also compared the endocrine data of 16 previously reported cases of Cushing's syndrome secondary to the release of ectopic corticotropin from ANS tumors. We concluded that in these patients, the plasma corticotropin level is only modestly elevated but indexes of steroid production frequently are markedly elevated. Also, discrepant responses to dexamethasone suppression tests occur, perhaps via sporadic release of corticotropin. These factors complicate evaluation of the cause of Cushing's syndrome in these patients.

Abnormal lactate dehydrogenase isoenzyme pattern in a critically ill patient

We have described a patient who had an abnormal isoenzyme of lactate dehydrogenase in both serum and tissue. The presence of LD6 is indicative of a poor prognosis. Some of the biochemical characteristics of the isoenzyme are (1) LD6 is not an artifact, (2) it contains an M subunit but not an H subunit, and (3) it is not an immunoglobulin complex. We believe LD6 may arise during episodes of severe shock as lysosomes rupture and is either a previously sequestered lysosomal LD or is a lysosomal modification of LD5.

Golden Syrian hamsters: a new experimental model for adrenal compensatory hypertrophy

We report that adrenal compensatory hypertrophy occurs in the golden syrian hamster, an animal secreting cortisol as the primary adrenal glucocorticoid. This response is seen at 3, 6, 10, and 21 days after unilateral adrenalectomy. The response is present in hypophysectomized hamsters and when endogenous ACTH secretion is suppressed by administration of dexamethasone by im injection or by dexamethasone and ACTH using the Alzet osmotic pump. Administration of either aldosterone alone or in combination with dexamethasone and ACTH by Alzet pump completely blocks adrenal compensatory hypertrophy after unilateral adrenalectomy.

Aldosterone blocks adrenal compensatory hypertrophy in the rat

We report that adrenal compensatory hypertrophy occurs in intact and hypophysectomized anesthetized rats as well as in rats in which endogenous ACTH is suppressed by administration of dexamethasone or of dexamethasone plus low-dose ACTH. However, adrenal compensatory hypertrophy is blocked in intact and hypophysectomized animals when aldosterone alone or the combination of aldosterone, dexamethasone, and ACTH is administered using Alzet pumps. These data support previous reports that questioned the validity of the hypothesis that adrenal compensatory hypertrophy is controlled by the glucocorticoid-ACTH negative feedback system. These results require modification of current hypotheses concerning the mechanism of adrenal compensatory hypertrophy to allow for a central nervous system or other effect of aldosterone.