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At least 1,081 records · Page 60Linked to original sources
PubMed1983

Characterization of N-ethyl-N-nitrosourea--induced mammary tumors in the rat.

A single intraperitoneal inoculation of 180 mg/kg N-ethyl-N-nitrosourea (ENU) into 30-day-old outbred Sprague-Dawley (CD) rats resulted in an 90% incidence of mammary tumors (MTs) after an average latent period of 93 days, with an 85% rate of malignancy. The incidence, induction period, number of tumors per rats, and the rate of malignancy were reduced in rats ovariectomized prior to or shortly after (5 days) ENU exposure. Over 70% of the ENU-induced MTs regressed following ovarioectomy. The malignant MTs developed from nodules located in the terminal end buds (TEB), which are believed to contain the most susceptible cell population for chemical carcinogens. The serum calcium was elevated above control values in 92% of intact rats evaluated with MTs in the absence of bone metastases. No correlation was demonstrated between the volume of MTs or total number of MTs and the serum calcium level. The ENU-induced MT is a reproducible animal model that can be used in the investigation of the early changes in mammary cells (especially TEB) and the interrelationships between the carcinogen and ovarian hormones associated with neoplastic transformation.

Adenofibroma↗
PubMed1983

Experimental lung nodule model: CT numbers, nodule size, and actual calcium content.

An experimental pulmonary nodule model was developed to study the effect of nodule size, nodule environment, and calcium content on the attenuation values in two computed tomography (CT) scanners. The experimental results show that (a) calcium is the moiety most responsible for the CT number, (b) small nodules may have falsely low CT numbers, (c) CT numbers vary from scanner to scanner when scanning the same nodule, and (d) higher CT numbers are obtained when experimental nodules are scanned in air rather than water.

Calcinosis↗
PubMed1983

Erythema nodosum associated with infectious mononucleosis.

Erythema nodosum is an immunoallergic epiphenomenon appearing during the course of various conditions; it has been exceptionally observed in association with infectious mononucleosis. A 9-year-old girl with clinical manifestations of infectious mononucleosis developed cutaneous nodules of erythema nodosum over the shins, which cleared after 12 days. Diagnosis was based on the presence of atypical mononuclear cells, detection of antibodies against Epstein-Barr virus, and positive ox red blood cell hemolysis. Coincidence of both diseases is not surprising because infectious mononucleosis may exhibit diverse immunologic reactions. On the other hand, commonest etiologies were excluded in this case.

Adolescent↗
PubMed1981

Hodgkin's disease involving the skin.

A 36-year-old patient developed discolored nodules over his sternum and left chest without systemic symptoms. Biopsy showed Hodgkin's disease; laparotomy revealed Hodgkin's disease in the spleen. This case illustrates the rare cutaneous presentation of Hodgkin's disease.

Adult↗
PubMed1994

Transmission of leprosy in nude mice through thorn pricks.

The dorsum of the feet of 10 nude mice was smeared with 10(7) Mycobacterium leprae and then pricked with cactus thorns contaminated with M. leprae. In 15 months five of them developed lepromatous nodules at the infected site and disseminated lesions in the ears, nose, tail and the organs of the reticuloendothelial system. Penetrating injuries through unprotected skin contaminated with M. leprae from the environment may play a role in the transmission of leprosy in humans.

Animals↗
PubMed1993

Prurigo nodularis.

Prurigo nodularis is a chronic skin disorder that is frequently misdiagnosed. It is characterized by multiple pea-sized nodules that develop on the skin, particularly on the anterior leg and thigh. These lesions are intensely pruritic and frequently become excoriated and infected. The cause of prurigo nodularis is unknown, and treatment is directed at reducing inflammation and controlling symptoms. The condition is typically of long duration and is refractory to treatment.

Female↗
PubMed1993

Percutaneous ethanol injection therapy for recurrent hepatocellular carcinoma.

Recently, small hepatocellular carcinoma (HCC) has been detected by following up patients with chronic liver diseases using ultrasonography (US). Most of the HCC patients have liver cirrhosis, and multinodular lesions are often found, even in cases of small HCC. Thus, surgical resection for small HCC is of limited efficacy. Our follow-up study indicated that a recurrent lesion was observed in 96.1% of small HCC cases after successful percutaneous ethanol injection therapy (PEIT). It is therefore very important to follow-up patients initially treated with PEIT with US for the detection of newly developed tumor nodules, because of the multicentric nature of HCC. A recurrence is subsequently again treated with PEIT. The 5-year survival rate of our 250 small HCC cases treated by PEIT is 46.7%. However, cases not followed by regular US after the first PEIT show significantly poorer 5-year survival rates. In future, it would appear to be of importance to search for means to inhibit or prevent recurrence.

Carcinoma, Hepatocellular↗
PubMed1977

Thyroid cancer after irradiation.

Nine patients with thyroid cancer who had received irradiation on the thyroid region (four for breast cancer with deep x-ray or Co60, one for a skin lesion with deep x-ray and four for hyperthyroidism with I131) have been discussed. These cases might be within the range of statistical coicidence, but the potential carcinogenic effect of irradiation could not be ruled out completely. The need for detailed examination of the thyroid gland before and for many years after irradiation and early removal of thyroid gland nodules which develop after I131 treatment are emphasized.

Adolescent↗
PubMedDate not supplied

[Polyarthritis in the elderly].

Ten to thirty-three per cent of all cases of rheumatoid arthritis (RA) develop after sixty years of age. Late-onset RA patients are more likely to be male, to have faster onset of symptoms, to experience shoulder and hip disease initially, and to have higher erythrocyte sedimentation rates; they are less likely to develop rheumatoid nodules, extraarticular manifestations, positive serologic tests, or unfavorable outcomes. There are roughly three patterns of late-onset RA: a classical form which resembles typical adult-onset RA; a limited, fairly mild form in which Gougerot-Sjögren syndrome often coexists; and a form in which the shoulders and hips are involved first. The latter form, whose early stage closely resembles polymyalgia rheumatica (PMR), accounts for approximately 25% of cases, is very specific of elderly patients, and is difficult to differentiate from PMR. RS3PE (Remitting Seronegative Symmetrical Synovitis with Pitting Edema) is a different entity from RA.

Aged↗
PubMed1995

Dissociation of two actions in the positive effect of prior partial hepatectomy on the induction of the hepatocarcinogenic process by diethylnitrosamine.

The present study was aimed at re-evaluating the mechanism by which partial hepatectomy (PH) and the resulting mitogenic stimulation act to positively modulate the action of a chemical hepatocarcinogen applied 24 hours after surgery. Using as a marker the immunocytochemical expression of glutathione S-transferase placental form (GST-P), we compared the early incidence of single altered hepatocytes and the time-course of appearance and growth of subsequently developed liver neoplasia in diethylnitrosamine (DENA) treated sham-operated or partially hepatectomized animals. The data showed that, compared to sham-operation, partial hepatectomy increases the frequency of early GST-P positive single hepatocytes appearing 72 h after treatment with DENA (50 mg/kg b.w.), indicating a positive (co-carcinogenic) effect of PH on the frequency of the initiation event. At 2 months after this treatment, foci of altered hepatocytes were about 5 times more numerous in PH-pretreated than in sham-operated animals and their average volume about four times greater. The latter difference persisted for up to 10 months after carcinogen treatment, indicating that the lesions had grown at similar rates in the meantime. The simplest hypothesis to account for this difference in size of the lesions is that it is due to the 2-3 waves of normal-like cell division the altered hepatocytes underwent during the very first days after removal of part of the liver mass, rather than to true promotion or to an intrinsic difference in proliferative phenotype of the initiated cells. The increased size and higher frequency of the lesions in PH-pretreated rats concur to increase the population of cells at risk towards subsequent events implied in multistep progression and, by this, to positively modulate the latter. Accordingly, only PH treated rats had developed neoplastic nodules at 10 months and tumours at 15 months. This can therefore be explained without resorting to the currently held view that cell divisions in PH would increase the carcinogenic efficiency of DENA, due to the fact that resulting cell divisions would intervene before full repair of DENA-induced DNA damages.

Animals↗
PubMed1997

Granulomatous contact dermatitis due to gold earrings.

A young female developed persistent nodules at sites of ear piercing with gold earrings and patch testing demonstrated a positive allergic response to gold sodium thiosulphate. Histological examination of the nodules demonstrated a prominent sarcoidal-type granulomatous tissue reaction. This is in contrast to previous reports of lymphocytoma cutis type histology and was associated with the occurrence of epithelioid granulomata at the site of a strongly positive and long-lasting patch-test reaction.

Adult↗
PubMed1998

Localized cutaneous Nocardia brasiliensis mimicking foreign body granuloma.

Nocardia brasiliensis is recognized in the United States as an infectious agent of the skin that may present as an abscess, ulcer, or granuloma with or without "sporotrichoid" spread, and rarely causes systemic disease. Treatment with trimethoprim/sulfamethoxazole is usually curative. We present a patient with multiple erythematous, painful, draining nodules that developed thirty-six months after trauma and subsequent contamination with soil in Bermuda. A foreign body granuloma was suspected clinically, and excision was performed followed by recurrence of the lesions. Histologic examination and culture were consistent with nocardiosis. Differential diagnosis of foreign body granulomas also should include infection with N. brasiliensis even after a long incubation period. Culture and drug susceptibility testing of affected tissue should be performed for diagnosis and management.

Adult↗
PubMed1976

The pathology associated with single and quadruple infections of hamsters with Dipetalonema viteae.

Two groups of five hamsters were each infected subcutaneously with infective larvae of Dipetalonema viteae; one group received single infections, and the second group received quadruple infections. A third group of five hamsters served as controls. Hamsters with primary and quadruple infections had cellular infiltrates in the liver and glomerular basement membrane thickening; these lesions were more extensive in the multiple than single infections. Hyperinfected hamsters also developed subcutaneous nodules. By histologic examination, it was seen that nodules were encapsulated abscesses which had a central, necrotic core, and were confined by a fibrous connective tissue capsule. The central portion of some nodules contained nondegenerated worms. The same area of other nodules contained dead worms, while still other nodules contained calcified worms or necrotic and calcified debris.

Abscess↗
PubMed1990

Characterization of skin lesions in mice following intradermal inoculation of Haemophilus ducreyi.

Twelve strains of H. ducreyi, which included two reference strains, were each inoculated intradermally into the flanks of CBA mice. All strains produced self-limited lesions which were macroscopically and microscopically typical of those seen in chancroid. Pustular nodules, about 5mm in diameter, developed at all inoculation sites by the second day when 10(7) organisms were inoculated. Approximately half of these lesions ulcerated and all had regressed by 2 weeks. Smaller nodules developed at about half the sites from the second to the fifth day when 10(6) or 10(5) organisms were given, but these did not ulcerate. No lesions were seen when 10(3) organisms were inoculated. Organisms were recovered from the lesions up to 11 days after inoculation. Specific H. ducreyi antigen, sought by a monoclonal antibody test, was detected in lesions up to 15 days following inoculation. Heat-killed organisms of H. ducreyi also produced nodules and ulcers although these were slightly smaller than those which developed after inoculation of viable bacteria. Similar lesions to those caused by H. ducreyi were produced after intradermal inoculation of about 10(8) viable or killed Neisseria gonorrhoeae organisms. Treatment of mice with ceftriaxone had little or no effect on the subsequent development of H. ducreyi-induced lesions. These findings indicated that the lesions were not produced specifically by viable H. ducreyi organisms. Ulcers were also produced following intradermal inoculation of purified lipopolysaccharide (LPS) from H. ducreyi or N. gonorrhoeae, but not by cell-free filtrates prepared from H. ducreyi cultures indicating a possible role for LPS in the pathogenesis of ulcerative skin lesions.

Animals↗
PubMed1981

Continuing occurrence of thyroid nodules after head and neck irradiation. Relation to plasma thyroglobulin concentration.

We re-examined 158 subjects from a group of 226 previously normal persons who had received head and neck irradiation, 113 with elevated plasma thyroglobulin levels at their first visit and 113 with normal levels. Twenty-four subjects had thyroid scintigrams that had changed in the follow-up interval of 24 to 60 (mean = 45.3) months. Twelve subjects subsequently had thyroidectomy, and five malignancies were found. In the other 12 the changes tended to be more subtle, but in nine they very likely represented thyroid nodules. We conclude that the prevalence of radiation-induced nodules is not decreasing. More changes (17 of 24) occurred in subjects who initially had elevated plasma thyroglobulin levels (p less than 0.05). However, the difference was not significant when the analysis was limited to the almost certain development of a nodule. Longer follow-up will be needed to ascertain whether a high thyroglobulin level predicts a greater risk of developing thyroid nodules.

Child, Preschool↗
PubMed1999

Characterization of nodular neuronal heterotopia in children.

Neuronal heterotopia are seen in various pathologies and are associated with intractable epilepsy. We examined brain tissue from four children with subcortical or periventricular nodular heterotopia of different aetiologies: one with severe epilepsy following focal brain trauma at 17 weeks gestation, one with hemimegalencephaly and intractable epilepsy, one with focal cortical dysplasia and intractable epilepsy, and one dysmorphic term infant with associated hydrocephalus and polymicrogyria. The connectivity of nodules was investigated using histological and carbocyanine dye (DiI) tracing techniques. DiI crystal placement adjacent to heterotopic nodules revealed numerous DiI-labelled fibres within a 2-3 mm radius of the crystals. Although we observed labelled fibres closely surrounding nodules, the majority did not penetrate them. Placement of DiI crystals within nodules also identified a limited number of projections out of the nodules and in one case there was evidence for connectivity between adjacent nodules. The cellular and neurochemical composition of nodules was also examined using immunohistochemistry for calretinin and neuropeptide Y (NPY), which are normally expressed in GABAergic cortical interneurons. Within heterotopic nodules from all cases, numerous calretinin-positive neurons were identified, along with a few cell bodies and many processes positive for NPY. Calretinin-positive neurons within nodules were less morphologically complex than those in the cortex, which may reflect incomplete differentiation into an inhibitory neuronal phenotype. There were also abnormal clusters of calretinin-positive cells in the overlying cortical plate, indicating that the migratory defect which produces heterotopic nodules also affects development of the cortex itself. Thus, heterotopic nodules consisting of multiple neuronal cell types are associated with malformation in the overlying cortical plate, and have limited connectivity with other brain regions. This abnormal development of connectivity may affect neuronal maturation and consequently the balance of excitation and inhibition in neuronal circuits, leading to their epileptogenic potential.

Brain Chemistry↗
PubMed2003

Landmark detection in the chest and registration of lung surfaces with an application to nodule registration.

We developed an automated system for registering computed tomography (CT) images of the chest temporally. Our system detects anatomical landmarks, in particular, the trachea, sternum and spine, using an attenuation-based template matching approach. It computes the optimal rigid-body transformation that aligns the corresponding landmarks in two CT scans of the same patient. This transformation then provides an initial registration of the lung surfaces segmented from the two scans. The initial surface alignment is refined step by step in an iterative closest-point (ICP) process. To establish the correspondence of lung surface points, Elias' nearest neighbor algorithm was adopted. Our method improves the processing time of the original ICP algorithm from O(kn log n) to O(kn), where k is the number of iterations and n the number of surface points. The surface transformation is applied to align nodules in the initial CT scan with nodules in the follow-up scan. For 56 out of 58 nodules in the initial CT scans of 10 patients, nodule correspondences in the follow-up scans are established correctly. Our methods can therefore potentially facilitate the radiologist's evaluation of pulmonary nodules on chest CT for interval growth.

Algorithms↗
PubMed2006

Silencing the flavonoid pathway in Medicago truncatula inhibits root nodule formation and prevents auxin transport regulation by rhizobia.

Legumes form symbioses with rhizobia, which initiate the development of a new plant organ, the nodule. Flavonoids have long been hypothesized to regulate nodule development through their action as auxin transport inhibitors, but genetic proof has been missing. To test this hypothesis, we used RNA interference to silence chalcone synthase (CHS), the enzyme that catalyzes the first committed step of the flavonoid pathway, in Medicago truncatula. Agrobacterium rhizogenes transformation was used to create hairy roots that showed strongly reduced CHS transcript levels and reduced levels of flavonoids in silenced roots. Flavonoid-deficient roots were unable to initiate nodules, even though normal root hair curling was observed. Nodule formation and flavonoid accumulation could be rescued by supplementation of plants with the precursor flavonoids naringenin and liquiritigenin. The flavonoid-deficient roots showed increased auxin transport compared with control roots. Inoculation with rhizobia reduced auxin transport in control roots after 24 h, similar to the action of the auxin transport inhibitor N-(1-naphthyl)phthalamic acid (NPA). Rhizobia were unable to reduce auxin transport in flavonoid-deficient roots, even though NPA inhibited auxin transport. Our results present genetic evidence that root flavonoids are necessary for nodule initiation in M. truncatula and suggest that they act as auxin transport regulators.

Acyltransferases↗