Reply to 'Do basal cell carcinomas recur after complete conventional surgical excision? R.W. Griffiths, S.K. Suvarna, J. Stone BJPS (2005);58, 795-805'.
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Biomedical subjects
Publications and source records attributed to D L Wallace.
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Interruption of appropriate therapeutic warfarin therapy imposes a risk of morbidity and mortality on the patient. Strategies to reduce the risks of interruption impose relatively large costs in terms of prolonged hospital stay, medication and coagulation monitoring. We report a series of 47 consecutive surgical episodes on the hands of 39 patients without interruption of therapeutic warfarin anticoagulation and with an INR of between 1.3 and 2.9. There was no difficulty with intraoperative haemostasis. Two patients had minor bleeding-related complications with no long-term sequelae. The authors conclude that interruption to warfarin therapy is unnecessary if the INR is less than 3.0 and therefore inappropriate for therapeutically anticoagulated patients undergoing hand surgery.
The CD45 antigen is essential for normal antigen receptor-mediated signalling in lymphocytes, and different patterns of splicing of CD45 are associated with distinct functions in lymphocytes. Here we show that abnormal CD45 splicing caused by a C77G transversion in exon A of the gene encoding CD45 (PTPRC) is associated with increased susceptibility to HIV-1 infection.
The leukocyte common (CD45) Ag is essential for normal T lymphocyte function and alternative splicing at the N terminus of the gene is associated with changes in T cell maturation and differentiation. Recently, a statistically significant association was reported in a large series of human thymus samples between phenotypically abnormal CD45 splicing and the presence of the CC chemokine receptor 5 deletion 32 (CCR5del32) allele, which confers resistance to HIV infection in homozygotes. We show here that abnormal splicing in these thymus samples is associated with the presence of the only established cause of CD45 abnormal splicing, a C77G transversion in exon A. In addition we have examined 227 DNA samples from peripheral blood of healthy donors and find no association between the exon A (C77G) and CCR5del32 mutations. Among 135 PBMC samples, tested by flow cytometric analysis, all those exhibiting abnormal splicing of CD45 also showed the exon A C77G transversion. We conclude that the exon A (C77G) mutation is a common cause of abnormal CD45 splicing and that further disease association studies of this mutation are warranted.
SCID is a heterogeneous group of hereditary diseases. Mutations in the common gamma-chain (gamma(c)) of cytokine receptors, including those for IL-2, IL-4, IL-7, IL-9, and IL-15, are responsible for an X-linked form of the disease, while mutations of several other genes, including Janus-associated kinase-3, may cause autosomal recessive forms of SCID. We investigated the first SCID patient to be described with minimal cell surface expression of the leukocyte common (CD45) Ag. CD45 is an abundant transmembrane tyrosine phosphatase, expressed on all leukocytes, and is required for efficient lymphocyte signaling. CD45-deficient mice are severely immunodeficient and have very few peripheral T lymphocytes. We report here that a homozygous 6-bp deletion in the gene encoding CD45 (PTPRC, gene map locus 1q31-32), which results in a loss of glutamic acid 339 and tyrosine 340 in the first fibronectin type III module of the extracellular domain of CD45, is associated with failure of surface expression of CD45 and SCID. Molecular modeling suggests that tyrosine 340 is crucial for the structural integrity of CD45 protein. This is the second description of a clinically relevant CD45 mutation, provides direct evidence for the importance of CD45 in immune function in humans, and suggests that abnormalities in CD45 expression are a possible cause of SCID in humans.
Enrichment of a subset of CD4(+)CD45R0(+)CD7(-) T cells has been observed in HIV-infected individuals. We have investigated the ability of CD7(+) and CD7(-) T cells to support replication of HIV and show that virus replicates preferentially in CD7(+) cells. Several possible mechanisms that may underlie such differences in susceptibility to HIV were studied. Our data demonstrate that mitogen stimulation induces poor expression of CD25 and IL-2 in CD7(-) compared with CD7(+) cells. We also show that uninfected CD7(-) cells are more resistant to mitogen-induced apoptosis than CD7(+) cells. Our data support the view that the CD7(-) subset is inherently resistant to HIV replication and that this is due in part to reduced CD25 expression and IL-2 production.
The leukocyte common antigen (CD45) is alternatively spliced, generating various isoforms expressed on hemopoietic cells. The splicing pattern of CD45 in T cells is altered in some individuals who show abnormal expression of high molecular weight isoforms containing exon A. The variant splicing pattern was shown to be associated with heterozygosity for a silent point mutation within CD45 exon A. This C to G transition is located 77 nucleotides downstream of the splice acceptor junction of exon A (198 bp total length). Here we report that this mutation is the cause of abnormal splicing. To isolate the mutant gene, somatic cell hybrids of lymphocytes with a CD45 splicing defect and a mouse lymphoid line were produced and clones expressing different isoforms of CD45 were isolated. Expression of the high molecular weight isoform containing exon A was associated with the mutation within exon A. All hybrids expressing the low molecular weight isoforms lacking exon A contained the normal allele of CD45 only. In addition, minigenes including this mutation were constructed and transfected into various cell lines (COS-7, HeLa, CHO). Semi-quantitative reverse transcription polymerase chain reaction showed an increase of more than tenfold in splicing to CD45RA (concomitant with a decrease in splicing to CD45RO) when compared with the normal minigene. Taken together, these results demonstrate a causal relationship between the mutation in CD45 exon A and the variant splicing pattern observed. The involvement of trans-acting splicing factors that interact with this region of CD45 pre-mRNA is currently under investigation.
A randomized phase II study of intraperitoneal (ip) mitoxantrone or floxuridine (FUDR) was performed for the treatment of minimal residual epithelial ovarian cancer found at second-look laparotomy after initial platinum-based chemotherapy. Entry was to take place within 30 days of reassessment laparotomies, with documentation of peritoneal metastases either microscopic or gross with cytoreduction to less than or equal to 1 cm in largest diameter. Patients were stratified by the site of the largest disease present (microscopic to 0.5 cm maximum diameter versus greater than 0.5 to 1 cm maximum diameter), by time of registration (< 14 days versus up to 30), and by serum CA-125 (< or = 35 versus >35 units/ml) prior to randomization to either ip mitoxantrone 10 mg/m2 every 2 weeks X 9 or ip floxuridine (FUDR) 3 g (total dose)/ day X 3 days every 3 weeks X 6 cycles. Implantable ip systems and 1.5-2 liters of normal saline were used to deliver the drugs of 83 patients registered between December 1988 and January 1994; there were 6 pathology exclusions and 9 surgical exclusions, and 1 nonevaluable patient for a total of 39 evaluable on mitoxantrone and 28 on FUDR being evaluable. FUDR is the choice for further study because of a progression-free survival exceeding 15% at 1 year over mitoxantrone and a median overall survival of 38 months. It should be emphasized again that the goal of a randomized phase II selection design is to select a winner for phase III testing should there be a substantial difference between the treatments with respect to the primary endpoint. Comparative conclusions between the treatment arms should not be attempted due to the inherently much smaller sample sizes. This should reemphasize the limitations in a comparison of efficacy; however, the toxicologic differences still emerge quite clearly.
The apoptosis of human cytokine-deprived activated T cells can be prevented by a soluble mediator secreted by fibroblasts, epithelial and endothelial cells, and this rescue occurs with fibroblasts from different species. Fractionation of W138 fibroblast-conditioned medium indicated that the survival-promoting agent(s) were > 30,000 MW. The continuous presence of the survival factor was required for prevention of apoptosis, which did not involve the induction of proliferation. Nevertheless, the co-cultured T cells remained in a primed state. The expression of the apoptosis-inducing proteins Bax and CD95 (Fas/Apo-1) was either unchanged or slightly increased in fibroblast-rescued T cells, suggesting that constraints on survival still existed after co-culture. A fundamental observation in the present study was that although Bcl-2 was reduced, the levels of Bcl-XL was maintained in cytokine-deprived T cells by fibroblast co-culture. This suggests that fibroblasts and/or other stromal cells may promote activated T-cell survival by a selective effect on Bcl-XL expression, which is consistent with histological examination of activated T cells within lymphoid tissue in vivo. The rescued T cell could be re-activated by CD3 antibody, but only in the presence of CD28 co-stimulation, which induced both Bcl-2 and Bcl-XL expression and also proliferation. Thus, survival signals from stromal cells in tissue microenvironments may enable activated T-cell persistence in a primed but quiescent state, and our data suggest that the regulation of Bcl-XL expression may be central in this process. The further characterization of this process is essential to clarify how signals from stromal cells can influence the resolution and/or chronicity of immune responses in different tissues in vivo.
A patient with menorrhagia, dysmenorrhea, and an enlarged uterus was treated with a GnRH agonist for leiomyoma volume reduction. A laser-assisted myomectomy yielded five tumors that did not appear to be well demarcated and had a combined weight of only 30 g. Postoperative pathologic evaluation revealed leiomyosarcoma with 22 mitoses per 10 high-power fields. The 8-month delay in therapy was associated with Stage IV, grade 3 disease at diagnosis. In rare cases GnRH agonist therapy may palliate symptoms and delay definitive surgical therapy of leiomyosarcoma, resulting in more advanced disease at diagnosis.
Human L-selection (LAM-1, Leu-8, TQ1, DREG 56) is a member of the 'selection' family of adhesion molecules. Antibodies to L-selectin have been shown to block the binding of T cells to peripheral lymph node high endothelial venules (HEV). Most unstimulated peripheral blood T cells express high levels of L-selectin whilst it is only weakly expressed on the majority of T cells from secondary lymphoid organs. We show here (a) that T cells from tonsil and lymph node up-regulate L-selectin when released from their microenvironment, (b) that in contrast, spleen contains a stable L-selectin negative subset, (c) that this subset remains surface L-selection negative after stimulation even though the T cells can respond by proliferation, (d) that this subset expresses minimal levels of LAM-1 mRNA and (e) that mucosal lymphocyte antigen (MLA) positive and T-cell receptor (TcR) gamma delta positive T cells found within the L-selectin negative population are similar to subsets of T cells found amongst lamina propria (LP) and intraepithelial lymphocytes (IEL) of the gut.
Endometrial carcinoma is the most frequent malignancy of the female reproductive tract, and irregular vaginal bleeding is the most common presenting symptom. Endometrial carcinoma is found most commonly among postmenopausal women and is associated with obesity, nulliparity, and anovulation. Oral contraceptive (OC) use and tobacco smoking have been reported to protect against endometrial carcinoma. Irregular vaginal bleeding is a common side effect of OC therapy. We report the case of an obese, premenopausal nulliparous woman with normal menses who developed menometrorrhagia and was then found to have endometrial carcinoma despite her youth and her use of both tobacco and combination OC.
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The Southwest Oncology Group conducted a phase II study of esorubicin treatment in patients with advanced endometrial cancer who had received no prior chemotherapy. Twenty of 31 patients were fully evaluable for response and toxicity. There were no clinical responses to treatment and 60% (12/20) of the patients developed severe or life threatening leukopenia on therapy. One evaluable patient was removed from study after a cumulative dose of 150 mg/M2 due to a reduction in left ventricular ejection fraction on MUGA scan and another developed congestive heart failure several months after discontinuation of treatment. Esorubicin has significant toxicity and limited clinical activity in patients with advanced endometrial cancer.
Forty-one eligible patients with metastatic or recurrent carcinoma of the uterine cervix received 149 courses of carboplatin. The drug was administered at a starting dosage of 400 mg/m2 IV every 28 days. The overall response rate was 15% (two complete responses, four partial responses; 95% confidence interval 6-29%) and response durations were 2.0, 2.0, 2.5 +, 2.5+, 5.25 +, and 6.75 months. The major toxic effects included nausea and vomiting in 48% of courses, anemia in 47%, leukopenia in 38%, and thrombocytopenia in 22%. The activity of carboplatin against advanced cervical cancer is modest and similar to the activity of cisplatin alone. However, the toxicity profile of carboplatin is substantially better than that of cisplatin and warrants exploration of this agent against cervix cancer in more aggressive regimens or in combination with other agents.
On the strength of recent evidence of the activity of the combination of cisplatin and 5-fluorouracil against squamous malignancies of the esophagus and head and neck, this regimen was evaluated in a phase II trial against metastatic or recurrent squamous carcinoma of the uterine cervix. Cisplatin was administered at a dosage of 100 mg/m2 iv bolus and 5-fluorouracil was continuously infused iv at a dosage of 1000 mg/m2/day for 4 days. In an effort to determine whether the toxicities of 5-fluorouracil could be ameliorated by coadministration of allopurinol, patients were randomized to receive allopurinol, 900 mg orally, an odd or even courses of therapy beginning 5 days before 5-fluorouracil administration and continuing until conclusion of the infusion. Fifty-two eligible patients received 177 evaluable courses of treatment. The overall response rate was 28% (8 complete responses and 6 partial responses). Toxicity was confined to nausea and vomiting (81% of courses), anemia (47%), leukopenia (37%), oral mucositis (15%), diarrhea (6%), and thrombocytopenia (4%). Allopurinol produced no improvement in treatment-related toxicities. Allopurinol did not permit substantial increases in 5-fluorouracil dosage.
Resting CD45RO+, mature/memory, T cells are phenotypically distinct from intermediate CD45RO+/CD45RA+ and CD45RA+, immature/virgin, T cells, and are characterized by high levels of expression of a number of adhesion molecules, such as CD2, CD18, CD58 and CD29. The kinetics of up-regulation of molecules, like CD25 and CD54 associated with activation, were similar in both subsets and suggested that their high level expression was associated with later events rather than initial recognition and signal transduction. CD45RA+ T cells, unlike CD45RO+ T cells, were unable to proliferate in response to mitogenic combinations of CD2 monoclonal antibodies (mAb), although in combination with submitogenic doses of PMA both up-regulation of cell-surface molecules and proliferation occurred. In addition, recruitment of CD45RA+ T cells by CD2 mAb-activated CD45RO+ T cells can occur.
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