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P Hui

Publications and source records attributed to P Hui.

28 records · Page 2Linked to original sources
PubMed1993

1,25-dihydroxyvitamin D3 enhances the transcription and expression of the inositol trisphosphate receptor gene in HL-60 cells.

Human leukemic HL-60 cells were treated with 1,25-dihydroxyvitamin D3 (VitD3) to induce monocytic cell differentiation. Concomitant with differentiation there was increased inositol-1,4,5-trisphosphate (InsP3) receptor expression, as assessed by both [3H]InsP3 binding site density and maximal InsP3-mediated Ca2+ mobilization from intracellular stores. Within 8 hr after VitD3 treatment the steady state level of a 10-kilobase InsP3 receptor mRNA was specifically elevated, and it continued to rise for 1-2 days. Nuclear run-off assays indicated a higher transcription rate of the InsP3 receptor gene in response to VitD3. The increased rate of transcription was sufficient to account for the increased steady state level of InsP3 receptor mRNA in VitD3-treated cells. VitD3 had no effect on the decay of InsP3 receptor mRNA in transcriptionally arrested cells; however, InsP3 receptor mRNA decay was dependent upon continued protein synthesis. Moreover, in cycloheximide-treated cells VitD3 was still able to induce an increase in the steady state level of InsP3 receptor mRNA, indicating that protein synthesis was not required for the enhanced transcriptional response. The results suggest that VitD3 directly enhances the transcription of the InsP3 receptor gene in HL-60 cells.

Binding Sites↗
PubMed1992

Transcriptional regulation and increased functional expression of the inositol trisphosphate receptor in retinoic acid-treated HL-60 cells.

The inositol trisphosphate (InsP3) receptor is an essential regulator of intracellular calcium in many cells including chemoattractant- and cytokine-stimulated neutrophils and differentiated promyelocytic leukemic (HL-60) cells. We examined the expression and function of the InsP3 receptor and the transcriptional regulation of the InsP3 receptor gene in HL-60 cells and in HL-60 cells treated for 1-5 days with 1 microM retinoic acid. Radioligand binding studies using membranes from control and retinoic acid-treated HL-60 cells showed that the Bmax of InsP3 receptor increased progressively from 0.24 to 0.69 pmol/mg protein during 5 days retinoic acid treatment with no change in KD (19 nM). During this period, maximal InsP3-stimulated Ca2+ mobilization increased 2-3-fold. InsP3 receptor mRNA was present at low levels in HL-60 cells but was increased significantly after treatment with retinoic acid, reaching maximal levels of approximately 4-fold greater than untreated cells after 4 days treatment with retinoic acid. Nuclear run-on assays indicated that the elevated steady state level of InsP3 receptor mRNA in retinoic acid-treated HL-60 cells was primarily the result of enhanced transcription of the InsP3 receptor gene. Furthermore, the transcriptional enhancing effect of retinoic acid was seen in the presence of cycloheximide, suggesting that the InsP3 receptor gene is directly regulated by retinoic acid. The studies also demonstrate that the InsP3 receptor mRNA is rapidly degraded in HL-60 cells by a mechanism that also requires protein synthesis.

Actins↗
PubMed1992

IL-3 and GM-CSF induce the expression of the inositol trisphosphate receptor in K562 myeloblast cells.

When treated with IL-3 plus GM-CSF, K562 myeloblast cells acquired the ability to mobilize nonmitochondrial stores of intracellular Ca2+ in response to added Ins (1, 4, 5) P3. Untreated K562 cells are capable of sequestering intracellular Ca2+ but released none of this Ca2+ in response to Ins (1, 4, 5) P3. Untreated K562 cells were shown to have no detectable specific [3H] Ins (1, 4, 5) P3 binding sites and no InsP3 receptor mRNA as assayed by Northern blot and PCR. However, following IL-3 and GM-CSF treatment, both a single class of low nM KD Ins (1, 4, 5) P3 binding site and a 10 kb InsP3 receptor mRNA were detectable. The results suggest that IL-3 and GM-CSF regulate the expression of the Ins (1, 4, 5) P3 receptor gene.

Blotting, Northern↗
PubMed1986

The groin flap in reparative surgery of the hand.

The historical literature of the use of axial vascular pattern flaps from the hypogastric and iliofemoral regions in reparative surgery of the hand is concisely reviewed. Thirty-six iliofemoral (groin) flaps were utilized for delayed primary resurfacing and secondary reconstruction of defects of the hand and forearm. Two flaps (6 percent) were complicated by partial necrosis. We caution against the immediate resurfacing (within 24 hours of injury) of acute crushed hand wounds by distant flaps. The immediate application of a healthy flap on a soiled or crushed wound invites complications of local tissue necrosis, infection, and subsequent loss of the flap. When distant flaps are indicated for coverage of acute hand wounds, delayed primary coverage following complete removal of all nonviable tissue is a safe and reliable regimen. It is advantageous to design the serviceable portion of the flap on the distal area of the vascular territory of the groin flap. Thoughtful yet "radical" defatting can be performed on the lateral portion of the groin flap territory. Constructed in this way, the long medial base of the groin flap allows freedom for movement at the wrist and metacarpophalangeal and interphalangeal joints, thus decreasing edema and stiffness. In the management of soft-tissue defects in the hand requiring distant flap coverage, we choose to utilize the conventional groin flap in preference to the microvascular free flap when both techniques will deliver equal results.

Groin↗
PubMed1983

Forearm replantation--long-term functional results.

The replantation of amputated extremities is justified only by the ultimate good function and appearance of the replanted part. This paper is a critical review of our clinical experience with forearm replantation and revascularization in 6 patients over the past ten years. All replanted parts survived. The long-term functional results of the forearm replants are analyzed. Return of function depends on nerve regeneration. The functional outcome in the first patient was unsatisfactory due to poor motor and sensory return. Specific attention directed to careful primary neurorrhaphy in subsequent cases yielded favorable results. We believe that two factors in particular are central in achieving good functional results in forearm replantation--careful repair of the severed major peripheral nerves, and postoperative hand rehabilitation programs.

Adult↗
PubMedDate not supplied

Bloom syndrome in sibs: first reports of hepatocellular carcinoma and Wilms tumor with documented anaplasia and nephrogenic rests.

The triad of small body size, immunodeficiency, and sun-sensitive facial erythema characterizes the phenotype Bloom syndrome (BS), a rare autosomal recessive disorder with a striking predisposition to multiple types of cancers that arise earlier than expected in the general population. Here we report two sibs with BS. The older, a 15-year-old-girl, developed a hepatocellular carcinoma, a neoplasm not yet reported in association with BS. Her younger brother developed an anaplastic Wilms tumor (WT) associated with nephrogenic rests at the age of 31/2 years, and this was followed by a myelodysplastic syndrome. Complex cytogenetic abnormalities were identified in all three neoplasms. These examples expand the spectrum of malignancies occurring in BS to include liver cell neoplasms, and confirm the association of nephrogenic rests with WT, even in the setting of BS.

Adolescent↗