Biomedical subjects
Publications and source records attributed to M Hansen.
The electrophoretic karyotype of fu1ur strains of P. stipitis and five strains of C. shehatae were compared by means of OFAGE and TAFE techniques. Although the number of chromosomal bands was six in all cases except one, P. stipitis revealed a clearly distinct pattern in comparison to C. shehatae. Both yeasts showed remarkable chromosome length polymorphism.
We have analyzed a series of Moloney murine leukemia (M-MuLV) envelope (env) protein fusions to the marker proteins invertase and placental alkaline phosphatase (PLAP), expressed in Psi2 retrovirus packaging cells. The yeast invertase protein, fused at its third amino acid residue to the amino-terminal signal sequence and 17 residues of the mature M-MuLV env protein, retained its enzymatic activity and was secreted from mammalian cells. However, env protein fusions to the C-terminal portion of invertase were inactive. In contrast, some, but not all, env protein fusions at the C-terminal region of PLAP were enzymatically active: PLAP fusions containing long C-terminal portions of env localized to the rough endoplasmic reticulum (RER) and possessed low enzyme activity levels, while fusion constructs containing relatively short portions of the M-MuLV env gene localized to the Golgi and had higher activity levels. Those proteins that localized to the Golgi also were processed, in part, to forms of 67 to 68 kDa, the size of the mature PLAP protein. Since PLAP ordinarily is transferred to a phosphatidyl-inositol glycan tail (PIG-tail) in the Golgi and then transported to the plasma membrane, it appears that Golgi-localized PLAP-env fusions are processed imperfectly. PLAP itself, when expressed in Psi2 cells, accumulated at the plasma membrane and, unlike the PIG-tailed Thy-1 protein, was not incorporated into virus particles. Thus, the reported incorporation of the Thy-1 protein into M-MuLV virions does not appear to be a consequence of its glycoprotein tail.
P-Cobalamins have been reported to be decreased in patients with HIV infection. Because of this, we found it of interest to examine both cobalamin-saturated binding proteins (holo-transcobalamin, holo-TC and holo-haptocorrin, holo-HC) and cobalamin unsaturated binding proteins (apo-transcobalamin, apo-TC and apo-haptocorrin, apo-HC). The results are given as range and (median). Eighteen male HIV-infected patients with plasma cobalamins below 200 pmol/l were studied. We found low concentrations of holo-TC (37-88 (47.5) pmol/l) and holo-HC (64-184 (135.5) pmol/l). The concentration of apo-TC and apo-HC was increased (480-1730 (1025) pmol/l; 70-800 (235) pmol/l). It is concluded that, in HIV-infected patients, low plasma cobalamin does not reflect a low concentration of transcobalamin or haptocorrin. In 20 HIV-infected patients and 31 patients with malignant haematological diseases, the TC isopeptide patterns were determined. In the HIV group, an increased frequency of TC isopeptide X was found and the overall distribution of TC isopeptides was significantly different from the reference population (p less than 0.05). There was no difference between the group of patients with malignant haematological diseases and the reference group.
1. Inhibition of 36Cl- efflux in frog muscle by the stilbene disulphonates (SD) SITS (4-acetamido-4'-isothiocyanato-stilbene-2,2'-disulphonate) and DNDS (4,4'-dinitro-stilbene-2,2'-disulphonate) depends on the external pH, while the blocking of Cl- conductance with SITS is independent of pH. The 36Cl- efflux inhibition with DNDS has been studied in thin depolarized muscle fibre bundles in order to examine whether this difference is consistent with one transporter or reflects the existence of two mutually independent conductive and non-conductive SD-sensitive Cl- pathways. 2. The 36Cl- efflux response to a sudden inward KCl gradient was studied. At high pH the efflux decreased as predicted for dominant conductive Cl- single-filing, and at low pH the efflux increased in agreement with dominant non-conductive Cl- antiport. DNDS inhibition resulted in the same response, an efflux decrease, at both high and low pH, suggesting a selective reduction of the non-conductive contribution at low pH. 3. The inhibition of 36Cl- efflux as a function of the DNDS concentration at an external pH of 6.9 showed complex kinetics, which could be described as the sum of two Michaelis-Menten functions with different half-inhibition concentrations of DNDS. 4. The results support the hypothesis that the stilbene disulphonate-sensitive Cl- transport is mediated by two separate transporters rather than one.
1. The pH- and voltage-dependent Cl- conductance in frog muscle may be related to the chloride equilibrium potential, VCl,eq, rather than to the absolute membrane potential, Vm. This hypothesis was tested in thin depolarized frog muscle fibre bundles by investigating the influence of pH on 36Cl- efflux during Cl- net efflux upon removal of external Cl-, which offers a state far from Cl- equilibrium by changing VCl,eq instead of Vm. 2. Upon the change from Cl- equilibrium at 20 mM-Clo- to Cl- net efflux at zero [Cl-]o, Vm changed only approximately 10 mV, but the 36Cl- efflux rate increased about three times at pH 5.5 and decreased to less than one tenth of the equilibrium efflux rate at pH 9.8. The switch between 'acid' and 'alkaline' responses occurs at a pH between 6.4 ('acid response') and 7.2 ('alkaline response'). 3. Changing pH between 5.5 and 9.8 during Cl- net efflux showed an increase of 36Cl- net flux rate upon acidification and a decrease upon alkalinization. The reactions are opposite to those seen by pH shifts at chloride equilibrium. 4. The changes of net flux rate coefficients upon changes of pH were transient, especially the activation at low pH that relaxed significantly during about 10 min. 5. The results are consistent with the notion that the state of the gCl mechanism in frog muscle is related to (Vm-VCl,eq) rather than to the absolute potential alone.
To examine the role of metabolic signals for ventricular myosin expression and activity of the sarcoplasmic reticulum Ca2+ pump, Wistar rats were treated for 7-8 wk with 5 or 50 mg/kg etomoxir, which inhibits fatty acid utilization. The proportion of myosin V1 was increased (P less than 0.05) with 50 mg/kg etomoxir (75 +/- 5% vs. 62 +/- 6% of control rats), whereas both doses increased the rate of Ca2+ uptake. A carbohydrate-rich fat-free diet or 8% sucrose drinking solutions, however, had no effect on myosin and sarcoplasmic reticulum. When rats were fed diets with an increased content (10 or 20%) of sunflower oil, the calorie intake and myosin V1 increased (56 +/- 8 or 64 +/- 8% vs. 44 +/- 6% of control rats). Isocaloric 10% fat diets of varying fatty acid composition (coconut fat, olive oil, or mackerel oil) also induced a higher calorie intake and increased V1 (64 +/- 6, 60 +/- 9, or 65 +/- 8% for the respective oils vs. 44 +/- 6% of control rats) but did not significantly increase rate of Ca2+ uptake. We concluded that calorie-rich diets changed the myosin expression not by affecting the ratio of fatty acid to glucose utilization but via the increased calorie intake.
PURPOSE: To report five cases of acute monocytic or myelomonocytic leukemia after chemotherapy with 4-epidoxorubicin for breast cancer and to evaluate the risk of leukemia after the use of this drug. PATIENTS AND METHODS: One hundred fifty-seven patients with advanced breast cancer were randomized to either 4-epi-doxorubicin plus cisplatin or 4-epi-doxorubicin alone. An additional 203 patients were treated prospectively with 4-epi-doxorubicin alone. All were observed closely for leukemic complications. RESULTS: Three patients from the randomized study developed leukemia; all were in the subgroup of 74 patients who received 4-epi-doxorubicin plus cisplatin, whereas no leukemia was observed among the remaining 83 patients in the randomized study or among the additional 203 patients who were treated prospectively with 4-epi-doxorubicin alone (P = .023, log-rank test). In the subgroup of 74 patients who were treated with 4-epi-doxorubicin plus cisplatin, the cumulative risk of leukemia was 16.0% +/- 9.9% (mean +/- SE) 33 months after the start of therapy; the relative risk was 668 (95% confidence interval [Cl], 138 to 1,953). Two other cases of acute monocytic and myelomonocytic leukemia were observed after 4-epi-doxorubicin plus alkylating agents were administered for breast cancer. Three of five cases of leukemia presented balanced translocations to chromosome band 11q23 and two, loss of a whole chromosome no. 7 or its long arm. CONCLUSIONS: 4-epi-doxorubicin is leukemogenic, and the leukemias are often acute monocytic or myelomonocytic with balanced chromosome translocations to band 11q23, such as in the leukemias after therapy with the epipodophyllotoxins. Furthermore, our results suggest a synergistic effect in leukemogenesis between 4-epi-doxorubicin targeting DNA-topoisomerase II and directly genotoxic drugs such as cisplatin or alkylating agents.
Explore the source record for details and available documents.
Transcobalamin (TC) and haptocorrin (HC) are present in normal seminal plasma in substance concentrations ten- to twenty-fold that in blood. The results are given in range and (median). The substance concentration of seminal plasma TC is 3.6-21.9 (8.4) nmol l-1 and of seminal plasma HC 1.4-8.6 (3.0) nmol l-1. Compared to normals the substance concentration of TC is significantly lowered in post-vasectomy seminal plasma 2.2-2.9 (5.3) nmol l-1. The Stokes radius and the isoelectric points of seminal plasma TC are identical to TC in blood.
The epipodophyllotoxin derivatives teniposide and etoposide have been under clinical investigation for over 15 years. Although etoposide has been established as one of the most active compounds in the treatment of small cell lung cancer (SCLC), teniposide has received little attention. The results of seven phase II studies evaluating response rate and duration of response to teniposide in 10 previously treated and 102 untreated patients showed response rates of 21% and 58%, respectively. The most frequently used dosage schedule was 60 mg/m2 intravenously daily for 5 days every 3 weeks. The following are factors influencing the response rate and duration of response to teniposide: performance status; prior weight loss; prior chemotherapy exposure, including prior treatment with etoposide; stage; and effectiveness of prior chemotherapy, including time from last administration. Preliminary analyses from a study comparing the efficacy of teniposide with that of etoposide suggest that teniposide may be more effective in previously untreated patients with SCLC who are 70 years of age or older. The preliminary data, however, indicate that equivalent doses of teniposide cause more cases of leukopenia than etoposide. Before a final conclusion can be drawn, the results from an ongoing study using teniposide and etoposide at equitoxic doses must be evaluated.
In 1987 a phase II study of combined high-dose platinum (carboplatin 300/mg/m2 day 1, cisplatin 50 mg/m2 days 2 and 3 q4wk) was carried out in 42 previously untreated ovarian cancer patients with residual disease. Since then, another phase II study of combined high-dose platinum and ifosfamide (1,500 mg/m2 days 1 to 3) has been carried out in 37 patients, while a third study of combined high-dose platinum and etoposide (70 mg/m2 intravenously days 1 to 5) is ongoing. Pathologic complete response (CR) and partial response (PR) rates in the first two studies were 62% in 37 evaluable patients, and 58% in 36 patients, 22% and 42% of whom were CRs, respectively. The preliminary results from the third study were: CR plus PR, 56%; CR, 24%. Hematologic toxicity was the dose-limiting factor in all three studies. Myelosuppression became substantial, but manageable, if another drug was added to the platinum combination. The percentage of patients experiencing World Health Organization grades 3 and 4 toxicity during treatment were: white blood cells 44%, 92%, and 79%; platelets 81%, 100%, and 95%, respectively, in studies I, II, and III. Nonhematologic toxicity was modest in all studies. Dose-limiting neurotoxicity occurred in 7%, 6%, and 5%; nephrotoxicity in 22%, 6%, and 11% of the patients. The percentage of patients receiving the stipulated doses of all study drugs in the sixth cycle was 31 in the first study compared with none in the second study. Combined high-dose platinum given either alone or in combination with ifosfamide or etoposide is highly active in ovarian carcinoma. However, further follow-up and a randomized trial are needed to establish the superiority of any one regimen.
Classical prognostic factors were analyzed in patients with low-risk primary breast cancer, defined as absence of tumor-positive axillary lymph nodes, tumor size less than or equal to 5 cm in diameter, and no invasion into skin or deep fascia. The primary surgical treatment was total mastectomy and lower axillary dissection. None of the patients received adjuvant therapy. Between 1977 and 1990, 7315 patients entered the study, and at the time of this analysis (January 1, 1990), the median follow-up time is 5 years. In univariate analyses, the following variables were significantly related to recurrence-free survival: age in premenopausal patients; tumor size; number of negative nodes removed; histological grade; and in premenopausal patients, estrogen receptor and progesterone (PgR) status. In multivariate analyses, age in premenopausal patients was the most important factor, followed by tumor size and histological grade, whereas PgR status in premenopausal patients was just of borderline significance. These variables should be included in multivariate analyses testing the value of more recently introduced prognostic factors.
Explore the source record for details and available documents.
In the follow-up programme of the DBCG-77 control and treatment protocols for primary operable breast cancer, bone scintigraphy and chest X-ray were performed 6 months after surgery and thereafter yearly until the diagnosis of any recurrence or another cancer. In the present study, the value of the two examinations was examined to the 6th year control. As a result of a low incidence of primary recurrence to the bone (0.6-3.9%) and to the chest (0.0-3.0%) the value was found to be low. About two thirds of the patients with primary chest recurrence addressed themselves with or had at the time of control pulmonary symptoms. About one half of those patients, in whom (during a 12-month period after the scheduled bone scintigraphy) bone metastases were diagnosed by another method, had a normal scheduled bone scintigraphy. False positive changes were not infrequent, especially at the bone scintigraphies. The diagnosis of asymptomatic chest recurrence did not reduce the mortality among stage II patients, among whom the greatest value of the control examination was found. It is concluded, that systematic use of bone scintigraphy and chest X-ray is not justified in a follow-up programme for stage I and II breast cancer patients.
The two therapeutic protocols of The Danish Breast Cancer Cooperative Group (DBCG) DBCG 77a (1977-1982) and 82a (1982-1990) comprise patients who were classified as low risk patients after operation for cancer of the breast, a total of 7,315 women. Treatment consisted of mastectomy and dissection of the lower and middle axillary levels. The median period of observation for DBCG 77a was 9 1/2 years and for DBCG 82a 3 1/3 years. The curves for recurrence-free survival and survival were found to be congruent in the two protocols. The recurrence-free survival after five years was 70% and 55% after ten years. Survival was 87% after five years and 70% after ten years. Local recurrence developed in 12.7% and 1.1% had distant recurrences simultaneously. Local recurrence was distributed with 60% in the scar or thoracic wall, 33% in the axilla and 7% in the clavicular lymph nodes. Distant recurrence alone developed in 11.4%. The time curves for development of local or distant recurrences were practically congruent. Local recurrence developed in 3.8% of the patients per annum during the first four years and after that in 1.5% per annum. Distant recurrence was found in 3.5% per annum in the first four years and after that in 1.8% per annum. The survival was significantly different after local and distant recurrence. Patients with tumours of grade 1 anaplasia had better prognoses than patient with grade 2 og 3 tumours as regards recurrence-free survival and survival. Multivariate analysis revealed that age under 40 years and anaplasia grad were significant prognostic variables for the parameters: distant recurrence and local recurrence. In addition, the number of lymph nodes in the operation specimen was a prognostic variable for local recurrence.
The role of antiestrogen treatment of postmenopausal breast cancer patients with high risk of recurrent disease is evaluated in a nationwide, prospective trial conducted by the Danish Breast Cancer Cooperative Group (DBCG). After total mastectomy and postoperative radiotherapy (RT), 840 patients were randomized to treatment with tamoxifen (RT + TAM) for one year, and 824 were randomized to no further therapy (RT). The recurrenceree survival (RFS) after ten years of lifeable analysis is 31% in the RT + TAM treated group, and 28% in the RT group (p = 0.01). Survival is 38% and 34% in the two treatment groups, respectively (p = 0.04). The data were further analyzed with respect to prognostic factors such as age, number of positive nodes, tumour size, and degree of anaplasia. Survival is prolonged in nearly all subgroups of patients treated with RT + TAM. However, the prolongation is only significant in patients with four or more positive nodes, with tumours of less than 5 centimeters or with tumours of anaplasia grade II. Estrogen (ER) and progesterone receptor (PgR) concentrations were measured in tumours from 309 and 219 patients, respectively. Only patients with ER and PgR values above 100 fmol/mg cytosol protein seemed to have a prolongation of survival. In conclusion, a modest survival benefit is achieved with one year of adjuvant tamoxifen treatment. Nevertheless, this is the first example of a systemic treatment approach being able to change the fatal course of breast cancer in postmenopausal patients. By means of endocrine therapy, and in the context of a new randomized trial, the DBCG will try to improve the survival in these patients even further.
From October 1977 to November 1982 premenopausal and menopausal high-risk breast cancer patients were included in a randomized trial (DBCG 77B). The primary surgical treatment was total mastectomy with axillary dissection. In the trial, a total of 1,034 patients were enrolled and received postoperative radiotherapy (RT) and were further randomized to 1) no systemic treatment, 2) cyclophosphamide, or 3) cyclophosphamide + methotrexate + 5-fluorouracil. The chemotherapy was given for one year. With a median observation time of ten years, the survival was 45, 60 and 62%, respectively. Retrospectively, the survival benefit was observed to be most pronounced in the age group less than 40 years, in patients with tumour size less than or equal to 5 cm or with less than or equal to 3 positive lymph nodes. In high-risk premenopausal and menopausal patients adjuvant chemotherapy combined with RT thus resulted in a more than 25% relative reduction in mortality at ten years of observation compared with RT alone.
Human monocytes obtained by counter-current centrifugal elutriation released arachidonic acid when challenged in vitro with Con A, as well as with other soluble (PMA or ionomycin) or particulate stimuli (serum-treated zymosan). Cyclo-oxygenase metabolites were the principal eicosanoids detected in the supernatants of Con A-stimulated, [3H]arachidonate-labeled monocytes, 5-Lipoxygenase (5-LO) products, such as leukotriene B4 (LTB4), were conspicuously absent. Release of arachidonate and its metabolites in response to Con A was dependent on the presence of extracellular Ca2+, but not Mg2+. In contrast to serum-treated zymosan challenge, which resulted in increased inositol trisphosphate and LTB4 release, Con A-induced inositol phospholipid hydrolysis in monocytes was limited to phosphatidylinositol or phosphatidylinositol monophosphate. Despite an inability to augment LTB4 release, Con A or PMA induced a loss of 5-lipoxygenase from a cytosolic compartment that was similar to that achieved with a calcium ionophore (ionomycin), a potent stimulus for LTB4 generation. When cell-associated LTB4 was evaluated, evidence for increased LTB4 production was obtained in response to either stimulus (PMA greater than Con A). In combination, however, PMA and Con A treatment resulted in monocyte LTB4 release comparable with that observed with the calcium ionophore or STZ. LTB4 release in response to all stimuli tested was inhibited by MK-886, a drug that binds to 5-lipoxygenase-activating protein. These results indicate the following: 1) Phospholipase A2 activation and attendant arachidonic acid release induced by agents that increase intracellular Ca2+ and/or generate diacylglycerol results in increased synthesis and release of PG and increased synthesis of leukotrienes, but not necessarily leukotriene release. 2) 5-LO translocation, which may occur independently of increased intracellular Ca2+, may be necessary for LTB4 generation but is insufficient for its release. 3) 5-Lipoxygenase-activating protein activity is necessary for 5-LO activation and LTB4 release in response to all stimuli investigated here. 4) Phorbol ester, an activator of protein kinase C, may synergize with agents such as Con A (which by themselves induce a minimal intracellular Ca2+ rise), so as to result in the release of LTB4. Thus, Con A may represent a class of surface receptor-aggregating agents that initiates inflammatory changes or immunomodulation associated with liberation of PG and might predispose to release of other inflammatory mediators, such as leukotrienes, in the presence of additional signals including protein kinase activation.