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K Howe

Publications and source records attributed to K Howe.

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

Characterization of cryptic rearrangements and variant translocations in acute promyelocytic leukemia.

Acute promyelocytic leukemia (APL) is typified by the reciprocal translocation, t(15; 17)(q22; q21), leading to the formation of PML-RARalpha and RARalpha-PML fusion genes. We have characterized 7 cases of morphologic APL found to lack the t(15; 17) on conventional cytogenetic assessment. In 6 of 7 cases, cryptic PML-RARalpha rearrangements were identified by reverse transcriptase-polymerase chain reaction and fluorescent in situ hybridization (FISH); whereas, in the remaining patient, APL was associated with the variant translocation, t(11; 17)(q23; q12-21), leading to the formation of PLZF-RARalpha and RARalpha-PLZF fusion genes. In each of the cases with cryptic PML-RARalpha rearrangements, PML-RARalpha transcripts were detected in the absence of RARalpha-PML, consistent with the concept that PML-RARalpha is the critical oncogenic fusion protein. In 4 of these cases with evaluable metaphase spreads, the occurrence of a nonreciprocal translocation was confirmed by FISH with sole formation of the PML-RARalpha fusion gene; in 3 cases with morphologically normal chromosomes 15 and 17, RARalpha was inserted into PML on 15q, whereas in the remaining patient the PML-RARalpha fusion arose due to insertion of 15q-derived material including PML into RARalpha on 17q. Immunofluorescence studies were performed using antibodies raised against PML and PIC 1, a ubiquitin-homology domain protein previously identified as an interaction partner of PML. In acute myeloid leukemia (AML) of subtypes other than M3, PIC 1 was localized to the nuclear membrane and colocalized with PML within discrete nuclear bodies. In APL cases with cryptic PML-RARalpha rearrangements, the characteristic microparticulate pattern of PML staining was detected with partial colocalization with PIC 1, indicative of disruption of the nuclear bodies; whereas in t(11; 17)-associated APL, PML and PIC 1 remained colocalized within discrete nuclear bodies, as observed in non-APL cases. Although deregulation of the putative growth suppressor PML and delocalization of other nuclear body constituents have been advocated to play a key role in the development of t(15; 17)-associated APL, the present study shows that disruption of PML nuclear bodies per se is not a prerequisite for the pathogenesis of APL.

Chromosomes, Human, Pair 15↗
PubMed1997

The management of cervical carcinoma within the south west region of England. Expert Tumour Panel.

OBJECTIVE: 1. To audit the management of cervical carcinoma in the South West Region with the aim of identifying and addressing deficiencies. 2. To determine whether recent NHS restructuring has affected the provision of cancer care. DESIGN: Retrospective review of hospital case notes. SETTING: All hospitals in the South West Region of England. POPULATION: Three hundred and twenty-four women with a diagnosis of cervical carcinoma: 191 were diagnosed in 1989 and 133 in 1993. MAIN OUTCOME MEASURES: Documentation of patient assessment and management. RESULTS: There was a mean delay of 17 days (range 0-66) from cervical smear to cytology report and 34 days (range 1-380) from general practitioner referral to attendance at a hospital clinic. Overall, 175 women (54%) had evidence of cytological assessment prior to treatment and 137 (42%) had a colposcopic assessment; 49% had cytological assessment and 37% had colposcopy in 1989, compared with 60% and 50%, respectively, in 1993. Excluding 49 cases of micro-invasive carcinoma, 238 case notes (86%) contained evidence of clinical examination; 195 women (71%) had had an examination under anaesthesia, 115 (42%) a chest radiograph, 123 (45%) an intravenous urogram or renal ultrasound, and 92 (33%) cystoscopy. One hundred and forty-seven women (53%) had FIGO staging recorded in the notes. As first line treatment, 69 had conservative surgery (39 for Stage IA), 138 had radiotherapy, and 107 had radical surgery. Ten had radical surgery for Stage IA but eight had a > 3 mm invasion or lymphatic/vascular spread. Thirty-one had Stage IB treated with radiotherapy of whom 14 were younger than 50 years of age. Following radical surgery 30% had evidence of sampling > or = 10 nodes, and 9% had tumour extending to the resection margins. CONCLUSIONS: Record keeping was inadequate but appeared to indicate inconsistent cytological, clinical, colposcopic and radiological assessment, leading to inappropriate clinical delays and conservative surgery. Radical surgery often appeared inadequate, but poor node sampling rates may also reflect insufficient histopathological preparation or reporting. There was a reduction in the number of new cases of cervical carcinoma diagnosed in 1993, perhaps reflecting an observed increase in cytological surveillance. No other alterations in clinical practice were observed over the four-year period. We feel it is imperative to standardise assessment throughout the region with a minimum clinical and histopathological dataset.

Adult↗
PubMed1996

PIC 1, a novel ubiquitin-like protein which interacts with the PML component of a multiprotein complex that is disrupted in acute promyelocytic leukaemia.

Acute promyelocytic leukaemia (APL) arises following a reciprocal translocation t(15;17) that fuses PML with retinoic acid receptor alpha (RARA). The PML-RARA fusion protein targets and disrupts nuclear multiprotein complexes called PODs, ND10 or NBs, a process which is associated with a block in myeloid differentiation leading to APL. A human B-cell cDNA library was screened for PML-interacting clones and a single positive clone (PIC1) was isolated. The sequence of PIC1 shows 52% identity to a S. cerevisiae ubiquitin-like protein that was cloned as a suppressor of mutations in MIF2, a protein required for mitotic spindle integrity during anaphase. Transient transfection of NIH3T3 cells with PIC1 results in a nuclear staining pattern coincident with that of endogenous mouse PML. Further, cotransfection of PIC1 with human PML produces a completely overlapping staining pattern between the two proteins. An antibody raised against PIC1 detects a punctate staining pattern in HeLa cells that is coincident with endogenous human PML. There is no significant colocalisation observed between the staining of PML/ PML-RARA and PIC1 in an APL-derived cell line NB4, as compared to cells expressing only wild type PML. However, following all trans retinoic acid treatment of NB4 cells a significant relocalisation of PIC1 and PML is observed. PIC1 is the first identified NB-associated protein that interacts with PML, the function of which may lead to a fuller understanding of the molecular events leading to APL.

3T3 Cells↗
PubMed1996

Fibrinolytic abnormalities in two different cutaneous manifestations of venous disease.

BACKGROUND: Chronic venous insufficiency may be associated with lipodermatosclerosis or atrophie blanche. Coagulation abnormalities may be related to these cutaneous disorders. OBJECTIVE: Our purpose was to determine whether fibrinolytic abnormalities exist in patients with lipodermatosclerosis or atrophie blanche. METHODS: A case control study of patients with venous disease and atrophie blanche or lipodermatosclerosis was performed. Plasma levels of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) in a resting and venous occluded state were measured. RESULTS: Plasma levels of PAI-1 were different between the two groups of patients. The lipodermatosclerosis group had significantly higher levels of PAI-1 in both the resting and venous occluded states (p < 0.001). Patients with atrophie blanche had milder elevations of PAI-1 in the resting and venous occluded state (p = 0.06). CONCLUSION: Fibrinolytic abnormalities are present in patients with venous disease. These abnormalities are different between patients with lipodermatosclerosis and patients with atrophie blanche.

Aged↗
PubMed1996

A retrospective study of the investigation and management of muscle-invasive bladder cancer in the South West Region.

OBJECTIVE: To evaluate the present management of muscle-invasive bladder cancer in the South West Region and to assess the workload resulting from the rationalization of treatment in specific centres. METHODS: A retrospective survey was undertaken in all the hospitals in the South West Region, to assess the management of all patients presenting with muscle-invasive bladder cancer in the years 1989 and 1993. Data were collected from histopathology records and hospital in-patients' notes. The optimum standard of assessment and treatment were defined by a panel of specialists in urological tumours. The management of patients was compared against these defined standards. RESULTS: A total of 186 and 199 patients in 1989 and 1993, respectively, were evaluated. When comparing their assessment against the defined standard, only 69% of patients in 1989 and 58% in 1993 had an intravenous urogram, with 7% and 4%, respectively, having no upper tract imaging (the remainder undergoing ultrasonography). Evidence from an examination under anaesthetic (EUA) was found for 80% of patients in 1989 and 84% of patients in 1993. Only 23% of patients in 1989 and 36% in 1993 were staged by either computed tomography or magnetic resonance imaging. In both 1989 and 1993, 54% of patients had definitive treatment, 31% had an endoscopic follow-up only and 15% had no treatment; there were no differences in age or co-morbidity among these groups. The median time elapsed between referral and diagnosis was 59 days (1989) and 52 days (1993), and the median delay to definitive treatment was 114 and 96 days, respectively. CONCLUSION: There was insufficient upper tract imaging, poor clinical staging in the EUA and too few investigations for staging. The low rate of definitive treatment may be a consequence of the delays in management, allowing the tumour to progress, and suggesting the need for a more rapid assessment of haematuria.

Adult↗
PubMed1996

Glycolic acid modulation of collagen production in human skin fibroblast cultures in vitro.

BACKGROUND: Glycolic acid has been used extensively for the treatment of photoaging and wrinkles. Suggestions have been made that glycolic acid may have specific dermal effects, although biochemical studies are limited. OBJECTIVE: This study's purpose was to examine the effect of glycolic acid on the radioactively labeled collagen production in human skin fibroblasts in culture. METHODS: Normal dermal fibroblasts were grown to semi-confluence and incubated in the presence of glycolic acid for 24 hours. Radioactive proline was added to the cultures. Using a specific amino acid assay, the amount of radioactive hydroxyproline was measured and was used as an accurate index of collagen production. RESULTS: Results show that glycolic acid caused an elevated collage production in the fibroblasts. CONCLUSION: These results demonstrate a specific stimulatory effect by the glycolic acid and could explain some of the positive benefits from the clinical use of glycolic acid.

Cells, Cultured↗
PubMed1996

Pityriasis rubra pilaris with acantholysis.

Two patients developed a papulosquamous eruption in a widespread distribution which progressed with islands of sparing of uninvolved skin characteristic clinically of adult-onset pityriasis rubra pilaris (PRP). Biopsies from both patients showed multiple areas of nonfollicular and follicular suprabasilar and intra-epidermal acantholysis with minimal dyskeratosis. They also showed the usual histologic features of PRP with a thickened orthokeratosis and parakeratosis, a retained and sometimes thickened granular cell layer, and psoriasiform epidermal hyperplasia with a perivascular lymphohistiocytic infiltrate in the superficial dermis. Two previous patients with PRP have been reported with nonfollicular, focal acantholytic dyskeratosis and both were interpreted as most likely representing an incidental finding. We believe the acantholysis in these two cases is related to the disease process, and in our second patient, was helpful in establishing the diagnosis.

Acantholysis↗
PubMed1996

Minimal residual disease detection in acute promyelocytic leukemia by reverse-transcriptase PCR: evaluation of PML-RAR alpha and RAR alpha-PML assessment in patients who ultimately relapse.

RT-PCR assays used to detect acute promyelocytic leukemia (APL) are generally considered less sensitive than those for other hematological malignancies, such as CGL. Most patients with APL express del(17q)-derived RAR alpha-PML transcripts as well as the putative leukemogenic PML-RAR alpha associated with add(15q). We have found that a nested RT-PCR for RAR alpha-PML affords greater sensitivity than that for PML-RAR alpha, particularly in patients with the commonest breakpoint pattern. Therefore, we have evaluated both assays in parallel to monitor a group of 12 de novo APL patients who relapsed despite treatment with both all-trans retinoic acid (ATRA) and chemotherapy. 5' (bcr 3) breakpoints in PML were over represented among the group and three patients had complex cytogenetic abnormalities suggesting both factors may increase the risk of relapse. The RAR alpha-PML assay changed the PCR status of two patients in morphological remission; in both cases disease contamination of bone marrow harvest specimens was detected. Although parallel assessment of PML-RAR alpha and RAR alpha-PML can enhance minimal residual disease detection in APL, this study demonstrates that treatment strategies involving determination of PCR status post-consolidation, even using RAR alpha-PML in addition to the more conventional PML-RAR alpha assay will fail to identify all patients at risk of relapse. Whether the duration of PCR positivity is a helpful prognostic indicator in those patients who ultimately become PCR negative is being addressed by

Adolescent↗
PubMed1996

Establishing the presence of the t(15;17) in suspected acute promyelocytic leukaemia: cytogenetic, molecular and PML immunofluorescence assessment of patients entered into the M.R.C. ATRA trial. M.R.C. Adult Leukaemia Working Party.

Detection of the t(15;17) or its molecular consequence, the PML-RAR alpha rearrangement, is critical for meaningful analysis of clinical trials involving patients with suspected acute promyelocytic leukaemia (APL). Its presence remains the best predictor of a favourable response to retinoids, such as ATRA, which in combination with chemotherapy confer significant improvements in disease-free survival. We have evaluated the relative efficacy of RT-PCR, cytogenetics and PML immunofluorescence staining to identify the existence of the translocation in 100 patients entered into the Medical Research Council (M.R.C.) ATRA trial. RT-PCR successfully identified PML-RAR alpha rearrangements in 93/100 patients, including 65 where only peripheral blood or post-induction marrow samples were available for analysis and in 12 patients in whom cytogenetic assessment failed to demonstrate t(15;17) due to poor-quality metaphases (10/12) or as a reflection of cryptic PML-RAR alpha rearrangements (2/12). Parallel employment of the RAR alpha-PML assay confirmed expression of del(17q)-derived transcripts in 81% and permitted determination of the PML breakpoint (a potential independent prognostic variable) in all 93 cases. Sequencing of RT-PCR products derived from 50 patients with 3' PML breakpoints revealed five bcr 2 cases, including a novel exon 5 breakpoint. 35/81 (43%) patients with cytogenetic evidence of t(15;17) possessed additional karyotypic abnormalities. In four patients with available buffy coat smears, lack of cytogenetic or molecular evidence of the t(15;17) was confirmed by a wild-type PML immunofluorescence nuclear staining pattern, in contrast to the characteristic microparticulate distribution detected in 14 patients with RT-PCR evidence of the rearrangement. However, although PML immunofluorescence staining is suitable for rapid determination of patients likely to benefit from ATRA, this approach does not obviate the need for cytogenetic and RT-PCR analysis of all patients entered into APL clinical trials, because both techniques provide additional information which may prove to be of independent prognostic significance.

Adolescent↗
PubMed1995

The solution structure of the RING finger domain from the acute promyelocytic leukaemia proto-oncoprotein PML.

Acute promyelocytic leukaemia (APL) has been ascribed to a chromosomal translocation event which results in a fusion protein comprising the PML protein and the retinoic acid receptor alpha. PML is normally a component of a nuclear multiprotein complex (termed ND10, Kr bodies, nuclear bodies, PML oncogenic domains or PODs) which is disrupted in the APL disease state. PML contains a number of characterized motifs including a Zn2+ binding domain called the RING or C3HC4 finger. Here we describe the solution structure of the PML RING finger as solved by 1H NMR methods at physiological pH with r.m.s. deviations for backbone atoms of 0.88 and 1.39 A for all atoms. Additional biophysical studies including CD and optical spectroscopy, show that the PML RING finger requires Zn2+ for autonomous folding and that cysteines are used in metal ligation. A comparison of the structure with the previously solved equine herpes virus IE110 RING finger, shows significant differences suggesting that the RING motif is structurally diverse. The role of the RING domain in PML nuclear body formation was tested in vivo, by using site-directed mutagenesis and immunofluorescence on transiently transfected NIH 3T3 cells. Independently mutating two pairs of cysteines in each of the Zn2+ binding sites prevents PML nuclear body formation, suggesting that a fully folded RING domain is necessary for this process. These results suggest that the PML RING domain is probably involved in protein-protein interactions, a feature which may be common to other RING finger domains.

Amino Acid Sequence↗
PubMed1994

Molecular analysis of simple variant translocations in acute promyelocytic leukemia.

The primary cytogenetic abnormality in acute promyelocytic leukemia (APL; FAB M3) is a reciprocal translocation, t(15;17)(q22;q12), which serves to fuse the PML gene on chromosome 15 to the retinoic acid receptor alpha (RARA) gene on chromosome 17. A PML-RARA fusion message transcribed from the der(15) is thought to mediate leukemogenesis. Two APL patients with simple variants of this translocation, t(3;15)(q21;q22) and t(X;15)(p11;q22), have previously been reported who lack cytogenetic involvement of chromosome 17, although their breakpoint positions on chromosome 15 still suggest the involvement of the PML gene. Here we report on a combined analysis by molecular genetics and in situ hybridization of these two patients, in which we wanted to determine whether the PML gene has alternative fusion partners or whether cryptic rearrangement of the RARA locus has occurred instead. A cryptic involvement of RARA was demonstrated in both patients by a combination of Southern analysis, reverse transcription coupled to PCR (RT-PCR), and fluorescence in situ hybridization. The results indicate an absolute requirement for the rearrangement of the RARA gene in the pathogenesis of APL and underline the importance of RARA during normal myeloid differentiation.

Adolescent↗
PubMed1994

A case of acute monocytic leukemia with t(11;17) involving a rearrangement of MLL-1 and a region proximal to the RARA gene.

A case of acute monocytic leukemia with t(11;17)(123;q11-21) arising in a 4-month-old boy is described. The breakpoint on chromosome 11 could be mapped to an 8-kb BamHI fragment within the MLL-1 gene, as seen in the majority of infant leukemias. In situ hybridization with cosmid probes allowed us to map the breakpoint on 17q proximal to the RARA gene, while Southern and Northern analyses showed that the gene was not disrupted by the translocation.

Chromosomes, Human, Pair 11↗
PubMed1993

Microcystic adnexal carcinoma: in vitro growth characteristics and effect on stromal collagen production.

BACKGROUND: Microcystic adnexal carcinoma (MAC) is a locally aggressive cutaneous neoplasm, which is characterized by follicular and sweat gland differentiation and a stroma of dense collagen. METHODS: MAC cells were studied and characterized in vitro through phase microscopy and proliferation assays. Additionally, to delineate a possible role of soluble mediators in bringing about the dense stromal collagen seen in association with these tumors, the effect of conditioned media derived from the tumor cells on the level of collagen production by normal fibroblasts was examined. RESULTS: A significant morphologic difference between the MAC cells and normal keratinocytes was not noted. Proliferation assays demonstrated a significantly slower rate of growth of the MAC cells in comparison to controls. Media conditioned by MAC cells did not induce an increase in collagen synthesis by cultured fibroblasts, but rather, there appeared to be an inhibitory effect on the level of collagen synthesis. CONCLUSIONS: The increased stromal collagen seen in MAC histologically is not the result of growth factors or cytokines produced by the MAC cells.

Carcinoma↗
PubMed1993

Patient-controlled analgesia and postoperative urinary retention after open appendectomy.

We retrospectively studied 279 patients who had undergone uncomplicated open appendectomy for acute appendicitis to determine risk factors for postoperative urinary retention. The gender of the patients, the operating time and the amount of fluid given perioperatively had no influence on the occurrence of retention. The amount of analgesic agent administered postoperatively and the age of the patient were significantly associated with urinary retention (p = 0.01 and p < 0.0001, respectively, after adjustment for potential confounding factors). The use of meperidine hydrochloride as compared with morphine and of patient-controlled analgesia as compared with intramuscular delivery were initially found to be significantly related to retention (p = 0.014 and p < 0.0001, respectively). After the effects of the age of the patient, the drug type and the amount of fluid and analgesic agent administered were controlled for, patient-controlled analgesia remained significantly associated with retention (p < 0.0001), whereas the type of drug given was no longer significant after controlling for potential confounding factors. Because we found that urinary retention was 13 times more likely to occur in the patients who had patient-controlled analgesia, we recommend that the use of this form of analgesia delivery be avoided after open appendectomy.

Adolescent↗