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At least 325 records · Page 18Linked to original sources
PubMed1985

Rhizobium leguminosarum genes involved in early stages of nodulation.

Nodulation genes from Rhizobium leguminosarum have been subcloned and transferred to a strain of R. phaseoli with its symbiotic plasmid deleted (and therefore its nodulation and nitrogen fixation genes). Normal infection and nodule development occurred when these strains were added to the roots of Pisum sativum (peas) and Vicia hirsuta. The pea nodules were examined by electron microscopy; bacteroid forms were seen surrounded by peribacteroid membranes and using immuno-gold labelling it was shown that the nodule cells contained leghaemoglobin within the cytoplasm. By subcloning and analysing the nodulation region it was found that a small (3.2 X 10(3) bases) fragment of DNA contained three genes involved in root hair curling, the first observed step in the interaction between R. leguminosarum and the root hair cells of these legumes.

Cell Membrane↗
PubMed1979

Pigmentation of osteoma cutis caused by tetracycline.

Blue nodules developed in the skin of a patient with acne concomitant with the start of tetracycline therapy. When removed, these nodules were brown and histologic examination revealed a lamellate structure compatible with bone. Under ultraviolet light, these osteomas fluoresced yellow, indicating the presence of tetracycline. This suggests that tetracycline, combined with new bone formation, causes pigmentation of osteoma cutis.

Acne Vulgaris↗
PubMed1994

Acanthamoeba sclerokeratitis.

We treated a healthy soft contact lens wearer who developed Acanthamoeba sclerokeratitis in the left eye. The patient had severe pain and ring-shaped subepithelial infiltrates. The keratitis progressed and scleral nodules developed despite aggressive treatment with topical clotrimazole, dibromopropamidine isethionate, and corticosteroids. Corneal transplantation and cryotherapy were performed. The corneal button demonstrated Acanthamoeba cysts. Cultures of biopsy specimens taken from two different scleral nodules at two separate times were positive for Acanthamoeba. The disease progressed despite a second corneal graft and the addition of polyhexamethylene biguanide eyedrops. Enucleation of the left eye was required. Histopathologic examination of the specimen documented an Acanthamoeba cyst associated with a granulomatous inflammatory response deep in the sclera. Acanthamoeba scleritis may be associated with a poor prognosis, even with intensive medical and surgical treatment.

Acanthamoeba↗
PubMed2004

A dual-genome Symbiosis Chip for coordinate study of signal exchange and development in a prokaryote-host interaction.

The soil-dwelling alpha-proteobacterium Sinorhizobium meliloti engages in a symbiosis with legumes: S. meliloti elicits the formation of plant root nodules where it converts dinitrogen to ammonia for use by the plant in exchange for plant photosynthate. To study the coordinate differentiation of S. meliloti and its legume partner during nodule development, we designed a custom Affymetrix GeneChip with the complete S. meliloti genome and approximately 10,000 probe sets for the plant host, Medicago truncatula. Expression profiling of free-living S. meliloti grown with the plant signal molecule luteolin in defined minimal and rich media or of strains altered in the expression of key regulatory proteins (NodD1, NodD3, and RpoN) confirms previous data and identifies previously undescribed regulatory targets. Analyses of root nodules show that this Symbiosis Chip allows the study of gene expression in both partners simultaneously. Our studies detail nearly 5,000 transcriptome changes in symbiosis and document complex transcriptional profiles of S. meliloti in different environments.

Bacterial Proteins↗
PubMed2005

Rheumatoid nodulosis. Two cases with destructive polyarthritis after 20 years.

The term "rheumatoid nodulosis" was coined by Ginsberg in 1975 to designate a rare and distinctive form of rheumatoid disease. Anecdotal case reports suggest a benign nondestructive course, although prolonged follow-up data are usually unavailable. We describe two cases of typical rheumatoid nodulosis with follow-ups exceeding 25 years. Onset occurred at 14 and 22 years of age, respectively. Both patients presented with palindromic rheumatism, positive tests for rheumatoid factors, negative tests for other biological markers, and normal radiographs. Multiple subcutaneous nodules developed after 4 and 6 years with palindromic flares, respectively. Functional impairments and disfigurement required several surgical procedures to remove nodules. Histology was typical for rheumatoid nodules. Neither patient responded to disease-modifying anti-rheumatic drugs (gold, antimalarials, and D-penicillamine). Treatment consisted of nonsteroidal anti-inflammatory drugs combined with prednisone as needed. After 20 and 22 years of follow-up, respectively, both patients had typical rheumatoid arthritis with deformities and radiological joint destruction. In conclusion, these two cases establish that rheumatoid nodulosis can occur as a presentation of rheumatoid arthritis with a potential for severe joint damage after many years.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1981

Sclerosing peritubular nodules: a hereditary renal abnormality in von Recklinghausen's disease.

A previously unrecognized type of renal lesion characterized by the formation of multiple hamartomatous sclerosing peritubular nodules in the cortex is described. These lesions were hereditary, appearing in three members of a family, which included the mother and her two sons, in association with familial central von Recklinghausen's disease (bilateral acoustic schwannomas). The nodules originated as concentric peritubular proliferations of collagen producing spindle cells, which ultrastructurally showed myofibroblastic differentiation. Four stages of nodule development leading to progressive sclerosis and tubular destruction are described. In spite of widespread involvement of the cortex with numerous nodules, in none of the three patients was there any clinical manifestation of renal dysfunction or hypertension.

Adult↗
PubMed2004

[A case of tinea capitis with a couple of nodular lesions possibly resulting from topical application of tacrolimus].

We herein report a case of tinea capitis initially showing a couple of nodular lesions. The patient was a 66-year-old woman who had seen a nearby dermatologist for itching on her head and had been treated with a topical steroid followed by tacrolimus application for one month. Because pseudolymphoma-like erythematous nodules developed at two sites, she visited us. Two weeks after stopping all medication, some slight scaling was found around these nodules. On KOH direct microscopic examination, many filamentous elements around hair shafts were observed. Biopsy of the nodules confirmed the destruction of hair follicles surrounded by granulomatous inflammation histologically. Grocott staining of the same specimen revealed a few short fungal hyphae as well as spores. She was also diagnosed as tinea pedis by direct microscopic examination of her feet. Trichophyton rubrum was isolated from scales of both her head and feet on Sabouraud's dextrose agar at 25 degrees C. Kerion celsi (KC) is usually clinically preceded by a gray patch or black dots. Such a typical course of KC, however, was not observed in our patient. Tacrolimus was thought to have possibly played an important role in modifying tinea capitis.

Administration, Topical↗
PubMed1988

[Inhibition of pulmonary metastases in mice by beta-cyclodextrin-benzaldehyde].

The effect of beta-cyclodextrin-benzaldehyde (CDBA) on the pulmonary metastasis in C3H/He mice was examined. When mice were treated daily with CDBA, 3 weeks later the number of lung nodules developed after i.v. inoculation of 1 X 10(6) RCT (+) cells was significantly decreased. The mean numbers of the lung nodules were 69.9 and 73.4 in the water-and cyclodextrin (CD)-treated mice, respectively. However, these were 17.8, 9.8 and 2.9 in 0.5, 5 and 25 mg/mouse per day CDBA-treated mice, respectively. And also, daily treatment of CDBA prolonged the survival time of the tumor bearing mice in both experimental and spontaneous metastasis studies. Two or three weeks after subcutaneous inoculation of RCT (+) cells (1 X 10(6) cells) to the foot pad, left hindlimbs were amputated and then mice were daily treated or untreated with CDBA. Five weeks after tumor inoculation, the number of lung nodules was counted. Twenty eight point six and 100% of untreated mice had lung metastases when amputation was carried out 2 (earlier operation group) and 3 (latero peration group) weeks after tumor inoculation. However, in CDBA-treated mice, these values were noticeably decreased, that is, 6.7% and 60% in earlier and later operation groups, respectively. Furthermore, in the later operation group, mean number of the lung nodules in CDBA-treated mice was only 2.7 while this was 12.9 in untreated mice. These data suggest that CDBA improve the survival time of tumor bearing mice through the inhibition of the lung metastasis.

Administration, Oral↗
PubMed2002

Newly developed rat brain pericyte cell line, TR-PCT1, responds to transforming growth factor-beta1 and beta-glycerophosphate.

Brain pericytes form an incomplete envelope around endothelial cells and within the microvascular basement membrane of capillaries and postcapillary venules. Recently, it has been reported that brain pericytes exhibit pluripotency, regulation of endothelial cell activity, and macrophage activity. However, many molecular and cellular aspects of brain pericytes remain unclear. In this study, we have tried to establish a conditionally immortalized brain pericyte cell line (TR-PCT) derived from the brain capillary of a transgenic rat harboring a temperature-sensitive simian virus 40 T antigen gene. One of the clones was named TR-PCT1, and we established 6 clones of pericyte-like cells from a 16 week-old tsA58 transgenic rat. For comparison, primary pericytes from a Wistar rat were also studied. The expression of platelet-derived growth factor receptor beta, angiopoietin-1, osteopontin, and intercellular adhesion molecule-1 in TR-PCT1 was determined by reverse transcription-polymerase chain reaction. Transforming growth factor-beta1 enhanced a-smooth muscle actin expression in TR-PCT1, but this expression was reduced by subsequent treatment with basic fibroblast growth factor. When TR-PCT1 was seeded on type I collagen plates and treated with beta-glycerophosphate, nodules developed in the cells and these nodules reacted positively to von Kossa stain used as a marker of calcification. We believe that TR-PCT1 will help us gain a better understanding of the physiological and/or pathophysiological role of pericytes.

Actins↗
PubMed2002

Dermatophyte granulomas caused by Trichophyton mentagrophytes in a dog.

Multiple, dermal and subcutaneous nodules developed in a young female Manchester Terrier dog that had a chronic history of superficial dermatophytosis. Skin biopsy specimens of the nodules revealed granulomatous inflammation in the deep dermis and subcutis with branching fungal organisms. Cultures of multiple biopsy specimens from the nodules all yielded Trichophyton mentagrophytes. The lesions in this dog were similar to granulomatous dermatophytosis, a skin disease that has been reported in Persian cats and one Yorkshire Terrier dog.

Animals↗
PubMed1995

Morphological and Molecular Characteristics of Host-Conditioned Ineffective Root Nodules in Cowpea.

In cowpea (Vigna unguiculata [L.] Walp.) a recessive allele, designated cpi, elicits the formation of non-N2-fixing nodules with all bacterial isolates tested. Comparisons of mutant and wild-type nodules demonstrated that the ineffective nodules were anatomically similar to the wild type and contained both infection threads and bacteroids. Ineffective nodules were smaller, however, largely because of the reduced size of the infected cells. Additionally, the number of bacteroids was reduced and senescence occurred prematurely in the infected cells. Grafting studies demonstrated that the defect in nodule development was controlled by the root rather than the shoot. Northern analysis of four nodulin genes indicated that in the ineffective nodules transcript levels of the early nodulin VuENOD2 were initially reduced but were equivalent to wild-type nodules by 21 d. In contrast, transcript levels of the early nodulin VuB were initially similar in both genotypes but as the nodules matured the mRNA levels declined more slowly in the ineffective nodules. The late nodulins leghemoglobin and uricase were expressed in the ineffective nodules but at greatly reduced levels. Thus, the cpi-conditioned defect in nodulation is associated with impaired bacteroid maturation and maintenance, altered nodulin expression, and accelerated senescence.

Journal Article↗
PubMed1987

Responses of Rj(1) and rj(1) Soybean Isolines to Inoculation with Bradyrhizobium japonicum.

We evaluated the symbiotic phenotypes of nodulation-restrictive and normal soybean isolines by inoculating Clark (genotypically Rj(1)Rj(1)) and mutant Clark-rj(1) (genotypically rj(1)rj(1)) seedlings in plastic growth pouches. Nodules first appeared on Clark seedlings inoculated with Bradyrhizobium japonicum USDA 94 after 6 days. The mean number of nodules per plant was 13.9 +/- 0.8 after 24 days. In contrast, Clark-rj(1) seedlings first nodulated at 12 days, and the mean number of nodules per plant was only 1.7 +/- 0.3 at 24 days. Segments from infectible zones of primary roots, i.e. near the position occupied by the root tip at the time of inoculation, were sectioned serially. Clark roots contained cortical cell divisions and a few infection threads in question mark-shaped root hairs by 2 days after inoculation. Typical nodules developed soon thereafter. Analogous serially sectioned segments from Clark-rj(1) roots lacked these responses. This prompted us to section nodules and adjacent tissues from other parts of Clark and Clark-rj(1) roots. Clark roots contained cortical cell divisions, many associated with infected root hairs. Cortical cell divisions occasionally were present in Clark-rj(1), and a few infection threads were visible in surface cells. The presence of infection threads within Clark-rj(1) nodules was confirmed by transmission electron microscopy. Thus, although B. japonicum USDA 94 fails to elicit the wild-type spectrum of responses in the infectible zones of primary roots, it can infect Clark-rj(1) via infection threads.

Journal Article↗
PubMedDate not supplied

Cutaneous infiltration by leukemic cells in acute promyelocytic leukemia of a child after treatment with all-trans retinoic acid.

We describe here the first case of childhood acute promyelocytic leukemia (APL) with cutaneous infiltration of leukemic cells following treatment with all-trans retinoic acid (ATRA) confirmed by immunostaining and polymerase chain reaction for PML/RAR alpha. An 11-year-old girl was diagnosed as having APL. Chromosomal analysis demonstrated the characteristic karyotype of t(15;17). ATRA therapy was begun at a dose of 45 mg/m2 daily. During ATRA therapy, leukocytosis and retinoic acid syndrome were observed but were resolved by dexamethasone. Two months after commencement of ATRA therapy, complete remission was achieved. During the course of consolidation chemotherapy, however, multiple cutaneous nodules developed in her trunk, the size and number of which increased despite intensive chemotherapy. Histological and immunological studies of the cutaneous nodules showed infiltration of leukemic cells. PML/RAR alpha mRNA was detected in both the cutaneous nodules and bone marrow by means of polymerase chain reaction. ATRA treatment for APL may be associated with an increased incidence of extramedullary disease such as cutaneous lesions. The best available therapy for APL may be a combination of ATRA and chemotherapy, especially when a marked leukocytosis occurs during ATRA therapy.

Antineoplastic Agents↗
PubMed1993

Leydig cell neoplasia in a patient with Reifenstein syndrome.

We present the rare coincidence of a Leydig cell tumor in both testicles of a patient with partial androgen insensitivity syndrome (PAIS). The clinical picture with perineoscrotal hypospadia, micropenis, gynecomastia and delayed puberty and the serum hormone levels with elevated concentrations of testosterone, luteinising hormone (LH) and follicle-stimulating hormone were entirely consistent with PAIS. Ultimately, the diagnosis was confirmed by determination of genital skin fibroblast androgen receptor binding capacity for 5 beta-dihydrotestosterone, which demonstrated a qualitatively abnormal androgen receptor. At 44 years of age, a nodule in the left testis led to orchidectomy. At that time, the right testis was inconspicuous sonographically. But 3 years later the right testis developed nodules and was removed. Review of testicular histology revealed the presence of Leydig cell hyperplasia (LCH), multifocal nodular hyperplasia and Leydig cell neoplasia (LCN) in both testes. Many micronodules of Leydig cells in transition from hyperplasia to neoplasia were also identified. The simultaneous development of histologically identical nodes of LCN independently from each other and a different sites of both tests indicates the presence of a tumorigenic factor acting on the Leydig cells. Furthermore, the observation of multiple foci of cells in all stages of transition from hyperplasia to neoplasia demonstrates the persistent process of transformation. We speculate, that in this patient the grossly elevated LH levels present over 30 years have enhanced, if not provoked, the formation of LCN. In addition, the defective androgen receptor might have prevented suppressive effects of androgens on the Leydig cells.

Disorders of Sex Development↗
PubMed1985

Conjunctival nodules associated with onchocerciasis.

A 14-year-old native of Ethiopia with previously treated onchocerciasis moved to California where he was examined for evidence of persisting nematode infestation. Skin and conjunctival biopsy specimens initially disclosed no abnormalities. Subsequently, conjunctival nodules developed, and a biopsy specimen of one of these revealed microfilariae of Onchocerca volvulus lying adjacent to a necrotic eosinophilic granulomatous inflammatory nodule. To our knowledge, nodules of this type have not heretofore been reported to be a notable feature of ocular onchocerciasis. This type of inflammation has a relationship to degenerating microfilaria in onchocerciasis and in other nematode infestation.

Adolescent↗
PubMed2004

Glutamine utilization by Rhizobium etli.

We undertook the study of the use of glutamine (Gln) as the source of carbon and energy by Rhizobium etli. Tn5-induced mutagenesis allowed us to identify several genes required for Gln utilization, including those coding for two broad-range amino acid transporters and a glutamate dehydrogenase. The isolated mutants were characterized by the analysis of their capacity i) to grow on different media, ii) to transport Gln (uptake assays), and iii) to utilize Gln as the C energy source (CO2 production from Gln). We show that Gln is degraded through the citric acid cycle and that its utilization as the sole C source is related to a change in the bacterial cell shape (from bacillary to coccoid form) and a high susceptibility to a thiol oxidative insult. Both these data and the analysis of ntr-dependent promoters suggested that Gln-grown bacteria are under a condition of C starvation and N sufficiency, and as expected, the addition of glucose counteracted the morphological change and increased both the bacterial growth rate and their resistance to oxidative stress. Finally, a nodulation analysis indicates that the genes involved in Gln transport and degradation are dispensable for the bacterial ability to induce and invade developing nodules, whereas those involved in gluconeogenesis and nucleotide biosynthesis are strictly required.

Bacterial Proteins↗
PubMed1990

Temporal and spatial regulation of the symbiotic genes of Rhizobium meliloti in planta revealed by transposon Tn5-gusA.

Tn5-gusA promoter/probe transposons have been constructed that fuse the Escherichia coli gusA reporter gene transcriptionally or translationally with a target promoter. These have been used to monitor expression of Rhizobium meliloti symbiotic genes within alfalfa nodules. Fusions in all 11 nod genes studied show the same pattern of expression: first on the root surface, then throughout the developing nodule, then mainly in the nodule meristem, falling off progressively through the central region, and then disappearing. In contrast, fusions in all five nif genes studied, all four fix genes, and syrM show a second, different pattern: expression beginning later, first throughout the nodule except for the meristem, strongest just behind the meristem, and falling off progressively through the central region. Novel features revealed by these studies include nod expression in the meristem, regulated in planta expression of control genes nodD1 and nodD3, disappearance of nod expression late in organogenesis, and properties of syrM.

Base Sequence↗