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D Long

Publications and source records attributed to D Long.

At least 37 records · Page 2Linked to original sources
PubMed1997

A Polycomb-group gene regulates homeotic gene expression in Arabidopsis.

Cell fate is determined when the commitment of cells to a particular fate is autonomously maintained, irrespective of their environment. In Drosophila, fate determination is maintained through the action of the Polycomb-group and trithorax-group genes, which are required so that states of homeotic gene activity are inherited through cell division. It is shown here that the CURLY LEAF gene of Arabidopsis is necessary for stable repression of a floral homeotic gene and encodes a protein with homology to the product of the Polycomb-group gene Enhancer of zeste. We suggest that Polycomb-group genes have a similar role in fate determination in plants and animals.

AGAMOUS Protein, Arabidopsis↗
PubMed1997

Outcome of preemptive renal transplantation and pretransplantation dialysis in children.

The present study compares the outcome of 40 children (39%) transplanted without prior dialysis, i.e., preemptive transplantation (PET), with 63 children (61%) transplanted after a variable duration of dialysis, i.e., pretransplantation dialysis (PTD). The two groups were matched for recipient and donor age and for immunological risk factors. There was no statistical difference in the time to first acute rejection episode nor in the number of acute rejection episodes during the 1st year after renal transplantation. In the PET group, 78% of the recipients received blood transfusion versus 92.5% in the PTD group (P < 0.05), and the average number of blood units per patient was 3.2 and 7.8, respectively (P < 0.05). Arterial hypertension was found in 55% of the patients in the PET group versus 73% in the PTD group (P < 0.05). The number of functioning grafts at the end of the study period was 87.5% in the PET group and 73% in the PTD group (NS). The major cause of graft failure was vascular thrombosis in the PET group (3/5) and chronic allograft rejection in the PTD group (10/17). In the PET group, the actuarial graft survival rate was 100%, 84%, 81%, and 76% at 1, 3, 5, and 7 years, which was not statistically different from the PTD group at 1, 3, and 5 years (98%, 91%, and 73%, respectively) but there was a significantly lower graft survival (59%) after 7 years in the PTD (P < 0.05). The 7-year actuarial patient survival rate was 97% in the PET group and 90% in the PTD group (NS). In the PTD group, children on dialysis for less than 1 year (group 1, n = 25) were compared with those on dialysis for more than 1 year (group 2, n = 38). Arterial hypertension was noted in 40% of patients from group 1 and 65% from group 2 (P < 0.05); there was no significant difference in graft loss rate. In conclusion, these results confirm PET as the preferred approach rather than PTD in children who need renal replacement therapy.

Child↗
PubMed1997

Ds elements on all five Arabidopsis chromosomes and assessment of their utility for transposon tagging.

The maize transposons Activator (Ac) and Dissociation (Ds) tend to transpose to sites close to their original position and can be efficiently used to transposon-tag genetically linked genes. To facilitate this approach, we describe the locations of seven T-DNAs carrying Ds elements, including at least one on each of the five chromosomes. For five of these T-DNAs, we have confirmed that the Ds element transposes preferentially to genetically linked sites. A large-scale transposon-tagging experiment was performed by activating Ds from eight chromosomal locations that included at least one on each of the five chromosomes. These experiments produced a total of 1132 F3 families that were predicted to carry around 870 independent Ds insertions. In these populations, 33 independently isolated mutants that were visibly different from wild-type were identified. Twenty-nine of these mutants were studied genetically, and 14 were not tagged with Ds because the element could be separated from the mutation by recombination. The remaining 15 mutations were possibly tagged because the transposon and the mutation were not separated by recombination. These experiments provide tools for transposon-tagging on each chromosome, and indicate that approximately 50% of identified mutations are likely to be tagged, thereby enabling cloning of the affected genes.

Arabidopsis↗
PubMed1997

Treatment of poison ivy/oak allergic contact dermatitis with an extract of jewelweed.

BACKGROUND: Jewelweed (Impatiens biflora) is a plant which has been used for centuries for the treatment of poison ivy/oak allergic contact dermatitis. Numerous claims for its effectiveness exist in the lay press, and over-the-counter medicaments containing jewelweed are reputed to be an effective remedy for poison ivy/oak dermatitis. Despite these claims, few scientific studies testing the effectiveness of jewelweed have been performed. OBJECTIVE: Our objective in this pilot study was to test the efficacy of an extract of jewelweed in the treatment of experimentally induced allergic contact dermatitis to poison ivy/oak. METHODS: A randomized, double-blinded, paired comparison investigation was performed. Ten adult volunteers were patch tested to urushiol, the allergenic resin in poison ivy/oak. For each volunteer, one patch test site was treated with an extract prepared from the fresh stems of jewelweed; the remaining site was treated with distilled water to serve as a control. Sites were examined on days 2, 3, 7, and 9 with reactions graded on a numerical scale. RESULTS: All subjects developed dermatitis at each patch test site. There was no statistically significant difference in the objective scores at the sites treated with jewelweed extract versus the distilled water control sites. CONCLUSION: This study demonstrated that an extract of jewelweed was not effective in the treatment of poison ivy/oak allergic contact dermatitis.

Adult↗
PubMed1996

Electrophoretic mobility of composite objects in free solution: application to DNA separation.

We propose here a simple procedure to estimate the electrophoretic mobility of composite objects obtained by linking two charged subunits, stressing that this electrophoretic mobility is in general different from the ratio of the total charge to the total friction coefficient. We focus especially on the situation where at least one of the subunits is a polyelectrolyte. Our remarks in particular correct the existing theoretical analysis of separation capabilities of devices in which a buoy (sphere, protein, polymer) is attached to a DNA chain. We also predict that, in some cases, the direction of electrophoretic motion can be reversed by increasing the electric field amplitude.

DNA↗
PubMed1996

Interstitial granulomatous dermatitis with arthritis.

BACKGROUND: Interstitial granulomatous dermatitis with arthritis is an uncommon systemic disorder involving the cutaneous and musculoskeletal systems. The eruption may mimic other dermatoses including granuloma annulare, erythema chronicum migrans, and the inflammatory stage of morphea. Key histopathologic characteristics, along with clinical correlation, allow accurate diagnosis. OBJECTIVE: We describe the clinical, serologic, and histologic features in three patients with interstitial granulomatous dermatitis with arthritis. METHODS: Skin biopsy specimens were examined and correlated with the clinical and laboratory findings. RESULTS: Erythematous, annular, indurated plaques on the extremities were present in two women. An erythematous, papular eruption on the head and neck was present in a third patient. All patients had myalgia and migratory polyarthralgias of the extremities along with various serologic abnormalities. Histologic examination revealed a dense lymphohistiocytic interstitial infiltrate involving primarily the reticular dermis. Foci of necrobiotic collagen were present. Vasculitis was absent. CONCLUSION: Interstitial granulomatous dermatitis with arthritis is unique multisystem disease with variable cutaneous expression. Abnormal serologic findings indicate a possible connection to collagen vascular disease.

Adult↗
PubMed1996

A Dissociation insertion causes a semidominant mutation that increases expression of TINY, an Arabidopsis gene related to APETALA2.

A novel transposon-tagging strategy designed to recover dominant gain-of-function alleles was performed with Arabidopsis by using a Dissociation element with a cauliflower mosaic virus 35S promoter transcribing outward over one terminus. Lines containing transposed copies of this transposon were screened for mutants, and a semidominant mutation affecting plant height, hypocotyl elongation, and fertility was recovered. The pleiotropic effects of this mutation appear to result from a general reduction in cell expansion, and some of the effects are similar to those caused by supplying exogenous ethylene or cytokinin to wild-type seedlings. In addition, the arrangement of cells in some organs such as the etiolated hypocotyl, is disorganized. The mutation was called tiny, and the affected gene was cloned by first using transposon sequences to isolate the mutant allele. The predicted protein product of the TINY gene shows strong homology with the DNA binding domain of a recently identified class of plant transcription factors. This domain, called the APETALA2 domain, was initially identified as a duplicated region within the APETALA2 gene of Arabidopsis and then as a conserved region between APETALA2 and the ethylene responsive element binding proteins of tobacco. In the mutant allele, the Dissociation element is inserted in the untranslated leader of the TINY gene, 36 bp from the ATG, and the mutant contains a novel transcript that initiates from the cauliflower mosaic virus 35S promoter within the transposon. This transcript is present in greater abundance than the wild-type TINY transcript; therefore, the semidominant tiny mutation most likely results from increased, or ectopic, expression of the gene.

Amino Acid Sequence↗
PubMed1996

A seven-transmembrane domain receptor involved in fusion and entry of T-cell-tropic human immunodeficiency virus type 1 strains.

Entry of human immunodeficiency virus type 1 (HIV-1) into cells requires binding to CD4 and fusion with a cellular membrane. Fusion does not occur in most nonhuman cells even when they express human CD4, indicating that one or more human accessory factors are required for virus infection. Recently, a seven-transmembrane domain protein has been shown to serve as an accessory factor for T-cell-tropic (T-tropic) HIV-1 isolates (Y. Feng, C. C. Broder, P. E. Kennedy, and E. A. Berger, Science 272:872-877, 1996). Here we show that expression of this glycoprotein, termed fusin, in murine, feline, simian, and quail cell lines, in conjunction with human CD4, rendered these cells fully permissive for HIV-1 envelope glycoprotein (Env)-mediated membrane fusion. Expression of CD4 or fusin alone did not permit fusion. In addition, introduction of fusin and CD4 into a human cell line, U87MG, that is resistant to HIV-1 induced syncytium formation and to infection by HIV-1 when expressing CD4 alone made this cell line permissive for Env-mediated cell-cell fusion. Fusion was observed only with T-tropic Env proteins. Macrophage-tropic (M-tropic) Env proteins from the SF162, ADA, and Ba-L HIV-1 strains did not fuse with cells expressing fusin and CD4, suggesting that M-tropic viruses utilize an accessory molecule other than fusin. Finally, coexpression of fusin and CD4 made both a murine and feline cell line susceptible to virus infection by T-tropic, but not M-tropic, HIV-1 strains.

Amino Acid Sequence↗
PubMed1996

Patient surveys in general practice: a randomised trial of an instant lottery ticket to increase return rate.

BACKGROUND: Patient surveys are becoming increasingly common and already are an obligatory activity to qualify for a Better Practice Program Grant. Strategies to increase return rates remain unevaluated in Australian general practice. AIM: To evaluate the effectiveness of an instant lottery ticket as a response-aiding technique in patient surveys. METHOD: A random sample of adult patients was selected from an age-sex-disease register, stratified by sex and randomised to receive an instant lottery ticket with the self-administered questionnaire mailed out in December 1994. RESULTS: There was no significant difference by group either for women (P = 0.68), men (P = 0.88) or both sexes combined (P = 0.68). However, irrespective of inclusion of the lottery ticket, men were significantly less likely to return questionnaires than women (P = 0.02). CONCLUSIONS: Instant lottery tickets do not increase return rates to questionnaires and are not recommended. Other strategies need to be tested, particularly to involve male patients in general practice research.

Adult↗
PubMed1995

Clinicopathologic analysis of macrophage infiltrates in breast carcinoma.

We compared macrophage density, assessed by enumeration of peritumoral mononuclear cell immunoreactivity for HAM 56, to clinicopathologic features and to immunostaining for two "invasion-associated" proteases (Cathepsin D and Urokinase plasminogen activator) in 80 breast carcinomas. Diffuse (2+) infiltrates of HAM 56- positive mononuclear cells were present in 27 cases (34%) and 43 (54%) exhibited focal (1+) infiltrates. Presence of 2+ macrophage infiltrates correlated significantly with poor differentiation. None of the seven well-differentiated cases exhibited 2+ infiltrates, whereas 9/43 (21%) moderately differentiated and 18/30 (60%) poorly differentiated tumors were diffusely infiltrated (p = .001). Wide-spread macrophage infiltrates were also more frequent in cases with advanced stage (23% of node negative vs 40% of node positive cases, p = NS). Forty-four percent of the cases with diffuse macrophage infiltrates were cathepsin D positive (i.e. in host derived cells) vs only 18% with focal macrophage infiltrates (p = .002). A similar relationship was observed between staining for HAM 56 and urokinase-type plasminogen activator (p = .02). Disease recurrences (50 months median follow-up) were more frequent in patients with 2+ (17/27, 63%) as opposed to 0+ (1/10, 10%) macrophage infiltrates (p = .01). We conclude that the density of stromal macrophage infiltrates is associated with clinical aggressiveness in breast carcinomas. Further, this relationship may reflect contribution of host derived macrophages to invasion and metastasis through elaboration of proteases which putatively mediate degradation and remodeling of extracellular matrix.

Breast Neoplasms↗