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Biomedical subjects

H J Wallace

Publications and source records attributed to H J Wallace.

At least 19 recordsLinked to original sources
PubMed1998

Levels of tumor necrosis factor-alpha (TNF-alpha) and soluble TNF receptors in chronic venous leg ulcers--correlations to healing status.

This study tested the hypothesis that excessive tumor necrosis factor-alpha (TNF-alpha) levels in chronic venous leg ulcers are associated with impaired healing. TNF-alpha was measured by two enzyme-linked immunosorbent assays and a bioassay (KYM-1D4) in paired wound fluid samples collected during the nonhealing and healing phases from 21 human patients with venous leg ulcers. Soluble TNF receptor levels (p55 and p75) were also measured. The levels of immunoreactive TNF-alpha were significantly higher in wound fluid from nonhealing ulcers than in wound fluid from healing ulcers (p < 0.005), whereas the levels of bioactive TNF-alpha were not. Statistical analysis confirmed that TNF-alpha bioactivity relative to the amount of immunoreactive TNF-alpha was downregulated in wound fluid from nonhealing ulcers compared with healing ulcers. The levels of soluble p55 and p75 receptors in wound fluid showed a significant linear correlation (p < 0.001), suggesting a partially coordinated or common regulatory mechanism for the cleavage of transmembrane TNF receptors in chronic venous ulcers in vivo. Although the levels of soluble p75 receptors were significantly higher in nonhealing wound fluid compared with healing wound fluid (p < 0.025), these levels were theoretically inadequate to substantially neutralize the bioactivity of the accompanying TNF-alpha levels on their own. The bioactivity accompanying the elevated levels of immunoreactive TNF-alpha in wound fluid from nonhealing ulcers may have been further down-modulated by an additional mechanism. Because healing was initiated without a significant decline in the level of bioactive TNF-alpha, TNF-alpha-mediated events may not be the key events contributing to the impaired healing seen in chronic venous ulcers.

Adult↗
PubMed1995

Intraoperative radiation therapy for locally advanced recurrent rectal or rectosigmoid cancer.

Recurrent rectal or rectosigmoid cancer is a difficult therapeutic problem. A treatment program of external beam irradiation, surgery, and intraoperative irradiation has been used for 41 patients. The 5-year actuarial local control and disease-free survival of all 41 patients was 30% and 16%, respectively. Subset analysis demonstrated differences in outcome by extent of surgical resection. The 5-year actuarial local control and disease-free survival of 27 patients undergoing complete resection was 47% and 21%, respectively. By contrast, the outcome of 14 patients undergoing partial resection was poor, with a 5-year actuarial local control and survival of 21% and 7%, respectively. Late complications included soft tissue or peripheral nerve injury, with many of these resolving within 4-18 months. Local control and disease-free survival rates are favorable in comparison with the results achieved by aggressive surgery. Patients who achieve a gross total resection at intraoperative irradiation have a markedly better prognosis than that of patients with residual gross disease.

Adenocarcinoma↗
PubMed1993

Combined radiotherapy and chemotherapy in the management of local-regionally advanced vulvar cancer.

PURPOSE: To determine, in a retrospective single institutional study, the role of concurrent radiotherapy and chemotherapy in the treatment of local-regionally advanced vulvar cancer. METHODS AND MATERIALS: From 1984 to 1991, 20 patients with locally extensive primary or recurrent carcinoma of the vulva were treated with initial combined radiotherapy and chemotherapy. Seven patients had Federation Internationale de Gynecologie et d'Obstretrique Stage III disease, 10 had Stage IV disease, and three were treated for recurrent disease. None of these patients were considered candidates for primary radical vulvectomy and groin node dissection. Median radiation doses to regions of microscopic disease and gross tumor were 40 Gy (range 30-54 Gy) and 54 Gy (34-70.4 Gy), respectively. All patients received 2 or 3 cycles of 5-Fluorouracil concurrently with radiotherapy. In addition, five patients received Cis-platinum, and one Mitomycin-C. Median at-risk follow-up interval was 37 months. RESULTS: Ten patients had complete resolution of tumor to initial chemoradiotherapy, and eight of these have remained free of tumor relapse. Eight other patients had partial responses, with tumor bulk reduced by > 50%, while the remaining two patients had local-regionally progressive disease. Six of the patients with partial responses had residual tumor successfully resected, although four subsequently recurred. For the entire group of 20 patients, the actuarial 3- and 5-year local control rates were 48% each, and the corresponding disease-specific survival rates were 59% and 49%. There was a suggestion that better local control was obtained in patients who received gross tumor radiation doses > or = 50 Gy. Skin reaction was the major acute toxicity and responded well to conservative management. Long-term sequalae were limited to skin and subcutaneous atrophy. CONCLUSION: These results indicate that initial combined radiotherapy and chemotherapy is effective in the management of advanced vulvar cancer.

Adenocarcinoma↗
PubMed1992

Potentiation of the activity of 1-beta-D-arabinofuranosylcytosine by the protein kinase C activator bryostatin 1 in HL-60 cells: association with enhanced fragmentation of mature DNA.

We have examined the interaction between 1-beta-D-arabinofuranosylcytosine (ara-C) and the macrocyclic lactone protein kinase C activator bryostatin 1 in the human promyelocytic leukemia cell line HL-60. Preexposure of cells to 10 nM bryostatin 1 for 24 h, followed by an additional 24-h incubation with 10 microM ara-C, resulted in greater than additive inhibitory effects toward clonogenic HL-60 cells. In a series of alkaline elution assays, cells preincubated with bryostatin 1 and prelabeled with [3H]thymidine exhibited a significant increase in DNA fragmentation following exposure to ara-C in comparison to cells exposed to ara-C alone. This increase in DNA damage was apparent at both neutral and alkaline pH and was not protein associated. In contrast, studies using cells pulse-labeled with [3H]thymidine immediately before analysis suggested that bryostatin 1 pretreatment did not increase the ability of ara-C to interfere with DNA replicative intermediates. Additional studies demonstrated that the increase in DNA fragmentation induced by bryostatin 1 and ara-C preceded both loss of cell membrane integrity (as determined by trypan blue exclusion) as well as depletion of intracellular ATP and NAD pools. Furthermore, the enhanced inhibitory effects of bryostatin 1 and ara-C toward clonogenic HL-60 cells did not appear to result from the induction of cellular differentiation. Finally, agarose gel electrophoresis of DNA obtained from cells exposed to both bryostatin 1 and ara-C revealed a pattern of integer multiples of 180- to 200-base pair fragments commonly associated with endonucleolytic cleavage; the extent of this fragmentation was considerably greater than that observed in cells exposed to ara-C alone. Taken together, these findings suggest that exposure of HL-60 cells to bryostatin 1 renders them more susceptible to ara-C-related DNA damage and that this phenomenon contributes to the cytotoxic effects of this drug combination. They also raise the possibility that bryostatin 1, perhaps through modulation of intracellular signaling events in leukemic cells, has the capacity to potentiate ara-C-related apoptosis or programmed cell death.

Adenosine Triphosphate↗
PubMed1992

Effects of bryostatin 1 and rGM-CSF on the metabolism of 1-beta-D-arabinofuranosylcytosine in human leukaemic myeloblasts.

The effects of the protein kinase C activator bryostatin 1, either with or without recombinant granulocyte-macrophage colony stimulating factor (rGM-CSF) were examined with respect to the in vitro metabolism of ara-C in leukaemic myeloblasts obtained from 10 patients with acute myelogenous leukaemia (AML). Coincubation of cells with 12.5 x 10(-9) M bryostatin 1 and 10(-5) M ara-C for 4 h resulted in a significant increase in ara-CTP formation (compared to controls) in 6/10 specimens (mean increase 106%; range 38-255%), and no change in the remainder. In contrast, coincubation of cells with 1.25 ng/ml rGM-CSF resulted in a significant increase in only one specimen, and decreases in two. Bryostatin 1 also significantly increased ara-C DNA incorporation in 6/9 evaluable samples, including two which did not display an increase in ara-CTP formation. Coincubation of cells with both bryostatin 1 and rGM-CSF did not lead to a further increase in ara-CTP formation or ara-C DNA incorporation compared to values obtained with either agent alone. Finally, exposure of blasts to bryostatin 1 for 24 h before ara-C led to an increase in ara-CTP formation in 3/8 additional specimens, and a decrease in one sample displaying evidence of bryostatin 1-induced macrophage differentiation. Incubation of cells with both rGM-CSF and bryostatin 1 for this period resulted in ara-CTP levels equivalent to those obtained with bryostatin 1 alone. These studies indicate that while bryostatin 1 exerts a heterogeneous effect on ara-C metabolism in leukaemic myeloblasts, it is capable of potentiating ara-C phosphorylation in a subset of patient samples, including some that do not exhibit an increase in response to rGM-CSF. They also raise the possibility that bryostatin 1-induced potentiation of ara-C metabolism in some leukaemic cells may contribute, at least in part, to the antileukaemic efficacy of this drug combination.

Antineoplastic Agents↗
PubMed1991

Metolazone pharmacokinetics and pharmacodynamics in renal transplantation.

Metolazone pharmacokinetics and pharmacodynamics were investigated in five renal transplant patients and five creatinine clearance matched controls. Whereas the time to peak metolazone excretion was similar in both groups (with the exception of one renal transplant patient who subsequently was found to have chronic rejection), the percent of the administered dose excreted over 48 h was significantly less in renal transplant patients (8% in renal transplant patients vs 24% in controls). Diminished bioavailability of metolazone or tubular secretion likely accounted for this disparity in metolazone excretion. Both groups developed diuretic tolerance as indicated by hysteresis in the dose response relationship. Cumulative sodium excretion over three successive 12-h time intervals did not differ between groups. Despite this comparable natriuresis, potassium excretion was significantly less in the renal transplant patients during the first day of the study. Accordingly, metolazone administration may provide a means to "unmask" subclinical, tubular secretory dysfunction in the transplanted kidney, as exemplified by defects in metolazone secretion and potassium excretion.

Adult↗
PubMed1988

DNA repair following incorporation of 5-fluorouracil into DNA of mouse bone marrow cells.

5-Fluorouracil (FUra) was previously demonstrated to be incorporated into DNA at cytotoxic concentrations in mouse bone marrow cells. Subsequently, we showed that under these conditions FUra exhibited a time-dependent removal from DNA accompanied by a decrease in DNA strand length. In the present study we utilized hydroxyurea to inhibit semiconservative DNA synthesis while monitoring DNA repair by measuring the incorporation of [3H]dThd into double-stranded DNA (DNAds), which can be separated from DNA at the replication fork (DNAss) by benzoylated-naphthoylated-DEAE cellulose. Under these conditions we assessed DNA repair in cells that had previously been exposed for 1 h to varying cytotoxic concentrations of FUra. The results demonstrate an increase in labelling of DNAds with increasing FUra concentrations, with no appreciable increase in incorporation of label into DNAss. In conclusion, this study demonstrates that DNA repair occurs following incorporation of FUra. The failure to repair DNA damage at higher FUra concentrations may have a role in the cytotoxicity of this drug.

Animals↗
PubMed1986

Alteration of the secondary structure of newly synthesized DNA from murine bone marrow cells by 5-fluorouracil.

The present study evaluates the effects of 5-fluorouracil (FUra) on the structure of newly synthesized DNA purified from bone marrow cells. DNA synthesis was decreased by 30 and 45% of control in the presence of 19 and 100 microM FUra, respectively. Furthermore at these concentrations of FUra, the DNA strand sizes were smaller as determined by alkaline sucrose gradients. Enzymatic digestion of the DNA demonstrated that most of the FUra (greater than 90%) was localized in the internucleotide linkage and not at the chain terminus. As the concentration of FUra was varied, the percentage of FUra at the chain terminus was unchanged, suggesting that the decrease in chain size as well as inhibition of DNA synthesis was not due to chain termination. DNA that had been synthesized in the presence of FUra was shown to fragment after increasing time as demonstrated by alkaline sucrose gradient analysis. This time-dependent fragmentation was associated with an increased number of strand breaks as determined by neutral and alkaline sucrose gradient analysis. A parallel study demonstrated a time-dependent excision of FUra from DNA over this same time period. In summary, these studies demonstrate an association between the excision of FUra from DNA and the changes in secondary structure of newly synthesized DNA.

Animals↗
PubMed1985

Dihydrofluorouracil, a fluorouracil catabolite with antitumor activity in murine and human cells.

Dihydrofluorouracil (FUH2), the initial catabolite of 5-fluorouracil (FUra), was examined to determine whether this derivative had antitumor activity or host cell (bone marrow) toxicity. Studies were undertaken with Ehrlich ascites tumor and bone marrow cells isolated from CF-1 mice. Cells were exposed for 1 h either to no drug (control) or to varying concentrations, ranging from 1 to 250 microM, of either FUra, FUH2, or alpha-fluoro-beta-alanine. Cells were then cultured and colony formation was assessed after 10 to 14 days. Ehrlich ascites tumor cells were more sensitive to FUra [50% lethal dose (LD50) = 18 microM] than to FUH2 [LD50 = 50 microM], with no sensitivity to alpha-fluoro-beta-alanine even at 250 microM. Bone marrow cells had a toxicity profile similar to that of FUra (LD50 = 10 microM) but were relatively insensitive to FUH2 (LD50 greater than 250 microM), with no sensitivity to alpha-fluoro-beta-alanine. Subsequent studies examined colony formation of the human breast carcinoma cell line MCF-7 following 1 h exposure to varying concentrations of FUra and FUH2. These cells were less sensitive to both FUra (LD50 approximately 80 microM) and FUH2 (LD50 approximately 350 microM). Initial studies on the mechanism of toxicity of FUH2 demonstrated that this FUra catabolite could produce inhibition of thymidylate synthase activity in Ehrlich ascites tumor cells with a pattern similar to that resulting from exposure to FUra. This is the first study to demonstrate that FUH2 (a quantitatively important catabolite of FUra) is cytotoxic, and it suggests that FUH2 may contribute to the toxicity of FUra in vivo, possibly by being anabolized to FUra.

Animals↗
PubMed1984

Response of warts in epidermodysplasia verruciformis to treatment with systemic and intralesional alpha interferon.

The susceptibility of human papillomavirus infection to polyclonal human leukocyte interferon (IFN-alpha) has been evaluated in patients with epidermodysplasia verruciformis (EV), a disease with extensive chronic papillomavirus-induced warts. In a double-blind, placebo-controlled study with intralesional IFN-alpha, four of five IFN-alpha-treated warts regressed; none of the placebo-treated warts responded (p = 0.024). Three patients with EV were treated with systemic IFN-alpha for 4 weeks in an open study, achieving partial regression of warts in all three. In a double-blind, placebo-controlled study, warts in two children with EV regressed with systemic IFN-alpha while two who received placebo showed no improvement. The lesions recurred following cessation of therapy. At the completion of therapy with IFN-alpha, histologic normalization was accompanied by a 95% decrease in the number of viral antigen-containing cells in the warts (p less than 0.001). We conclude that warts in EV respond to systemic and intralesional IFN-alpha.

Adult↗
PubMed1984

5-Fluorouracil incorporation into DNA of CF-1 mouse bone marrow cells as a possible mechanism of toxicity.

Isolated CF-1 mouse bone marrow cells were exposed for 1 hr to 5-fluorouracil (FUra) at concentrations from 1.8 to 50 microM and then washed and suspended in a soft agar growth medium to assess the effect on toxicity (measured as reduction in colony growth compared to control). These data were used to determine specific toxic concentrations ranging from 25 to 90% lethal doses. Subsequent studies examined in parallel the effect of these toxic concentrations of FUra on the possible sites of toxicity including: (a) inhibition of thymidylate synthetase activity using a modified 3H release assay; (b) incorporation of FUra into RNA (FUra-RNA); and (c) incorporation of FUra into DNA (FUra-DNA). Thymidylate synthetase activity was slightly decreased (75% of control) after 1-hr exposure to a 50% lethal dose and was not significantly further reduced as the FUra concentration was increased to an 85% lethal dose. Furthermore, subsequent exposure of FUra-treated cells to a nontoxic thymidine dose (5 microM) failed to reverse toxicity. FUra-RNA increased during 1-hr exposure to increasing concentrations of FUra (25 to 90% lethal doses). Although initially suggesting a relationship between the level of FUra-RNA and toxicity, subsequent studies in cells exposed to FUra in the presence of uridine demonstrated a significantly decreased toxicity while, at the same time, a minimal decrease of FUra in RNA. In contrast, FUra-DNA was significantly decreased in the presence of uridine and correlated with decreased toxicity. In additional subsequent studies, an apparent decrease in subsequent DNA synthesis was observed (measured by 32P or [3H]thymidine incorporation into DNA) as the level of FUra-DNA increased. In conclusion, FUra is demonstrated to be incorporated into DNA of isolated CF-1 mouse bone marrow cells, and the level of FUra-DNA appears to be closely associated with toxicity and inhibition of further DNA synthesis. The parallel studies of thymidylate synthetase activity and FUra-RNA suggest that FUra-DNA may be an unrecognized mechanism of FUra toxicity in these cells.

Animals↗
PubMed1980

Anderson-Fabry disease. Characteristic ultrastructural features in cutaneous blood vessels in a 1-year-old boy.

Electron microscopy of clinically uninvolved skin taken from a 12-month-old male child with biochemically proven angiokeratoma corporis diffusum showed characteristic lamellar lipid deposits within endothelial and perithelial cells of dermal blood vessels. Ultrastructural examination of skin may aid the early identification of males affected with Anderson-Fabry disease long before the development of specific skin lesions.

Blood Vessels↗
PubMed1978

Electrocardiographic changes following adriamycin treatment.

Two hundred and fifty-six patients with a wide variety of advanced neoplasms who were treated with adriamycin at Roswell Park Memorial Institute were studied for electrocardiographic changes. All the patients had pre- and posttreatment electrocardiograms (ECG's) and changes were found in 85 (33.2%). In the group of 1-8 patients with normal pretreatment ECG's, changes occurred in 51 (30.3%). In the group of 88 patients who had abnormal pretreatment ECG's, 34 (38.6%) developed further changes following treatment. Twenty-five patients received cytoxan concomitantly and ECG changes developed in 12 (48%); however, this and the above difference were not statistically significant. Frequency of ECG changes was higher and the extent of histologic abnormality in the myocardium was greater in those patients who received high doses of adriamycin. Arrythmias were rather benign and only a small number of patients required treatment. ECG changes following adriamycin treatment occurred more frequently than previously reported.

Arrhythmias, Cardiac↗
PubMed1977

Carcinoembryonic antigen in osteosarcoma.

Plasma carcinoembryonic antigen (CEA) assay was done in 30 patients with osteosarcoma. CEA was found positive (greater 2.5 ng/ml) in 17 of 21 patients who had active evidence of disease and negative (less than 2.5 ng/ml) in all 9 patients who were in complete remission resulting from previous amputation of chemotherapy. Serial CEA determinations demonstrated a fall to normal in 7 of 9 patients following successful surgery of chemotherapy and a ruse and fall (fluctuation) of levels in 8 patients who had tumor progression while on chemotherapy. Clinical recurrence of disease in two instances preceded or coincied with CEA elevation. The CEA assay in osteosarcoma although non-specific could be used as an inportant adjunct to experienced clinical judgment, periodic x-ray examination, and laboratory study to prognosticate the course of osteosarcoma during therapy. The interpretation of a rising or falling CEA titer alone, however, must be made with caution.

Adolescent↗