Testing the impact of virus importation rates and future climate change on dengue activity in Malaysia using a mechanistic entomology and disease model.

We aimed to reparameterize and validate an existing dengue model, comprising an entomological component (CIMSiM) and a disease component (DENSiM) for application in Malaysia. With the model we aimed to measure the effect of importation rate on dengue incidence, and to determine the potential impact of moderate climate change (a 1 °C temperature increase) on dengue activity. Dengue models (comprising CIMSiM and DENSiM) were reparameterized for a simulated Malaysian village of 10 000 people, and validated against monthly dengue case data from the district of Petaling Jaya in the state of Selangor. Simulations were also performed for 2008-2012 for variable virus importation rates (ranging from 1 to 25 per week) and dengue incidence determined. Dengue incidence in the period 2010-2012 was modelled, twice, with observed daily weather and with a 1 °C increase, the latter to simulate moderate climate change. Strong concordance between simulated and observed monthly dengue cases was observed (up to r = 0·72). There was a linear relationship between importation and incidence. However, a doubling of dengue importation did not equate to a doubling of dengue activity. The largest individual dengue outbreak was observed with the lowest dengue importation rate. Moderate climate change resulted in an overall decrease in dengue activity over a 3-year period, linked to high human seroprevalence early on in the simulation. Our results suggest that moderate reductions in importation with control programmes may not reduce the frequency of large outbreaks. Moderate increases in temperature do not necessarily lead to greater dengue incidence.

Studies of phlebotomine sand fly (Diptera: Psychodidae) populations in limestone areas and caves of western Malaysia.

Phlebotomine sand flies were collected using CO2 baited CDC light trap in 2000 and 2001 in limestone areas and caves of western Malaysia. A total of 1,548 specimens were collected comprising 18 species from two genera: Phlebotomus (6 spp) and Sergentomyia (12 spp). Phlebotomus major major (38.9%) was the predominant species followed by Sergentomyia perturbans (20.1%), P. stantoni (15.3%) and others. Biting activity of the sand flies at the Gua Senyum caves, Gua Kota Gelanggi, Batu caves and Gua Kelam were observed using the bare leg landing catch (BLC) technique. Four Phlebotomus spp at Gua Senyum were found to bite humans with a unimodal biting peak (between 01:00 and 04:00 AM). At Gua Kota Gelanggi P. major major was observed to bite humans, but at Batu Caves and Gua Kelam no sand flies were observed to bite humans. Sergentomyia spp did not feed on humans even though high numbers were caught in light traps. The populations of phleobotomine sand flies fluctuated, with several peaks especially among P. major major which peaked in December and was low in February and August. Phlebotomus stantoni was abundant throughout 2001. Most species populations were weakly related to rainfall because they inhabited caves.

Targeting pulmonary metastases of renal cell carcinoma by inhalation of interleukin-2.

INTRODUCTION: Pulmonary metastases of renal cell carcinoma (RCC) are associated with poor prognosis. Inhalation therapy with interleukin-2 (IL-2) is thus an appealing method for palliation. This multicenter study summarizes the national experience of IL-2 inhalation in patients with lung metastases of RCC. PATIENTS AND METHODS: Forty patients (median, 66.5 years of age) with radiologically documented progressing pulmonary metastases were enrolled. All patients had to be able to comply with inhalation technique, and were not candidates for other treatment options. Twenty-eight patients were systemic treatment-naïve. The protocol included three daily inhalations of IL-2 to a total dose of 18 MU. Treatment had to be continued until one of the following occurred: progression; a complete response; a life threatening toxicity; or patient refusal. Response was assessed using the Response Evaluation Criteria in Solid Tumors (RECIST) system. RESULTS: The disease-control rate reached 57.5%, with a partial response rate of 2.5% and a disease stabilization rate of 55%. Median time to progression was 8.7 months. The main side-effects were cough and weakness. CONCLUSIONS: Inhalation of IL-2 for the treatment of pulmonary metastases in RCC is feasible, tolerable and beneficial in controlling progressive disease for considerable periods of time. The definition of response of biological therapy may need to be re-assessed and modified: stable disease should be regarded as a favorable response.

[The chemotherapeutic treatment of advanced Hodgkin's disease].

Between 1972 and 1994, 121 adult patients with advanced Hodgkin's disease received MOPP (M) combination chemotherapy, MOPP alternating with ABVD (M-A) or MOPP and ABV hybrid (M/A). Radiation therapy was given to 1/3 of them. The median age was 35 years, 58% had stage III and 42% had stage IV disease. Failure-free survival at 10 years was 43.9%. It was 66.7%, 48.4% and 29.9% for patients treated by M/A, M-A and M, respectively. Overall survival at 10 years was 40.8%, and 78.2%, 48% and 27.7% for patients treated by M/A, M-A and M, respectively. Multivariate analysis found age (above or below 65 years) and combination chemotherapy (with or without adriamycin) to be significant prognostic factors. M/A combination was more myelotoxic, while M combination caused more second primaries. Today, 80% of patients with advanced Hodgkin's disease may be cured, with low rate of long-term toxicity.

Effects of Ca(2+)-ionophore A23187 and calmodulin antagonists on regulatory mechanisms of glycolysis and cell viability of NIH-3T3 fibroblasts.

We studied here, in NIH-3T3 fibroblasts, the effect of the Ca(2+)-ionophore A23187 (which is known to increase intracellular-free Ca(2+)) on the control of glycolysis and cell viability and the action of calmodulin antagonists. Time-response studies with Ca(2+)-ionophore A23187 have revealed dual effects on the distribution of phosphofructokinase (PFK) (EC 2.7.1.11), the rate-limiting enzyme of glycolysis, between the cytoskeletal and cytosolic (soluble) fractions of the cell. A short incubation (maximal effect after 7 min) caused an increase in cytoskeleton-bound PFK with a corresponding decrease in soluble activity. This leads to an enhancement of cytoskeletal glycolysis. A longer incubation with Ca(2+)-ionophore caused a reduction in both cytoskeletal and cytosolic PFK and cell death. Both the "physiological" and "pathological" phases of the Ca(2+)-induced changes in the distribution of PFK were prevented by treatment with three structurally different calmodulin antagonists, thioridazine, an antipsychotic phenothiazine, clotrimazole, from the group of antifungal azole derivatives that were recently recognized as calmodulin antagonists, and CGS 9343B, a more selective inhibitor of calmodulin activity. The longer incubation with Ca(2+)-ionophore also induced a decrease in the levels of glucose 1,6-bisphosphate and fructose 1,6-bisphosphate, the two allosteric stimulatory signal molecules of glycolysis. All these pathological changes preceded the reduction in cell viability, and a strong correlation was found between the fall in ATP and cell death. All three calmodulin antagonists prevented the pathological reduction in the levels of the allosteric effectors, ATP and cell viability. These experiments may throw light on the mechanisms underlying the therapeutic action of calmodulin antagonists that we previously found in treatment of the proliferating melanoma cells, on the one hand, and skin injuries, on the other hand.

Dexamethasone, cytarabine, ifosfamide, and cisplatin as salvage therapy in non-Hodgkin lymphoma.

The authors conducted a phase II study to evaluate a new combination of chemotherapeutic drugs that includes dexamethasone, cytarabine, ifosfamide, and cisplatin as salvage therapy in non-Hodgkin lymphoma after prior exposure to both adriamycin and etoposide. All drugs were administered intravenously over 4 consecutive days. The daily dose of dexamethasone was 20 mg twice daily. The maximal daily doses of cytarabine, ifosfamide, and cisplatin were 75 mg/m2, 1,200 mg/m2, and 20 mg/m2, respectively. Cycles were repeated every 3 weeks. A total of 31 patients were entered in the trial. Thirty patients were evaluable for response. A complete response was seen in 11 patients (37%), and a partial response was noted in six patients (20%). A significantly higher complete response rate was seen in patients with relapsing non-Hodgkin lymphoma compared with those who failed to achieve a complete response with the last chemotherapy (10/14 vs. 1/16; p < 0.013). A complete response continues in two patients who received consolidation with high-dose chemotherapy for more than 49 months and more than 60 months for each patient. Median time to treatment failure and median survival were 3.3 months and 7.5 months, respectively, for the entire group and 11 months and 30 months, respectively, for complete responders. Myelosuppression was pronounced but was usually of short duration. Neutropenic fever developed in 13 patients (42%) and in 15 of 96 cycles (16%). Platelet transfusions were required in seven patients (23%). There was one drug-related death associated with myelotoxicity. Nonhematologic toxicity was not dose limiting. The authors conclude that dexamethasone, cytarabine, ifosfamide, and cisplatin is active and a relatively tolerable regime for patients with non-Hodgkin lymphoma previously treated with adriamycin and etoposide.

Insulin stimulates binding of phosphofructokinase to cytoskeleton and increases glucose 1,6-bisphosphate levels in NIH-3T3 fibroblasts, which is prevented by calmodulin antagonists.

We report here a novel mechanism of insulin action in cultures of NIH-3T3 fibroblasts. Our experiments revealed that in these cells, insulin induced a rapid and transient increase in cytoskeleton-bound phosphofructokinase (EC 2.7.1.11), the rate-limiting enzyme in glycolysis, with a corresponding decrease in soluble (cytosolic) activity. Insulin also induced a slower increase in the levels of glucose 1,6-bisphosphate, the potent activator of cytosolic glycolysis. Both the rapid and the slower stimulatory actions of insulin were prevented by treatment with structurally different calmodulin antagonists, which strongly suggest that calmodulin is involved in these effects of insulin. The present and our previous experiments in muscle suggest that rapid, Ca2+-calmodulin-mediated increase in the binding of glycolytic enzymes to cytoskeleton, as well as the slower increase in glucose 1,6-bisphosphate, may be a general mechanism, in different cells, in signal transduction of insulin.

Continuous interleukin-2 infusion combined with cyclophosphamide- based combination chemotherapy in the treatment of hemato-oncological malignancies. Results of a phase I-II study.

The combination of a cyclophosphamide (CTX)-based chemotherapy regimen and interleukin-2 (IL-2) has been shown to provide synergistic effects against malignancy in animal models. We therefore conducted a phase I-II trial combining CTX-based combination chemotherapy or CTX alone with high-dose IL-2 in patients with advanced and refractory malignant disease. Fifteen patients with hemato-oncological malignancies (malignant lymphoma 8, multiple myeloma 3, solid tumor 2, leukemia 2) were enrolled in the study. Continuous high-dose IL-2 infusion was shown to be safely administered, starting as soon as recovery of white blood cell count. All patients developed rebound lymphocytosis 24-48 h after termination of IL-2 infusion. Although grade IV toxicity was observed in 5 patients (7 episodes), all side effects completely subsided. Triple chemotherapy (CTX, etoposide and Ara-C) seemed rather toxic (in this group of heavily treated patients) while CTX alone was well tolerated. Four out of 13 (31%) evaluable patients had partial response and another patient (7%) had stabilization of disease progression lasting 2-8 months. Our conclusion is that the combination of CTX and continuous infusion of IL-2 is feasible and should be investigated in patients with various malignant neoplasms.

Inhibin A concentrations in the sera of young women during and after chemotherapy for lymphoma: correlation with ovarian toxicity.

PROBLEM: Inhibin A concentrations in serum may reflect the ovarian granulosa cell compartment. To characterize the correlation between ovarian function after gonadotoxic chemotherapy for Hodgkin's or non-Hodgkin's lymphoma in young women, the immunoreactive inhibin A concentrations in the sera of these patients was measured before, during, and after the gonadotoxic chemotherapy. METHOD OF STUDY: A prospective clinical protocol was undertaken in 20 cycling women with lymphoma, aged 15-40 years. A monthly injection of depot D-TRP6-GnRH-a (Decapeptyl CR, Ferring) was administered from before starting the chemotherapy until its conclusion, up to a maximum of six monthly injections. Most of the patients were treated with the mustargen-oncovin-procarbazine-prednisone (MOPP)/actinomycin D-bleomycin-vincristine (ABV) chemotherapy combination; 13 with and 7 without radiotherapy. A hormonal profile [follicle-stimulating hormone (FSH), luteinizing hormone (LH), 17-beta-estradiol (E2), testosterone (T), progesterone (P4), insulin-like growth factor (IGF)-1, IGF-BP3, and prolactin (PRL)] was taken before starting the gonadotropin-releasing hormone agonist (GnRH-a)/chemotherapy co-treatment and monthly thereafter until resuming spontaneous ovulation and menstrual cyclicity. This group of prospectively treated lymphoma patients was compared with a control group of 22 regularly cycling women who had been treated with chemotherapy (mostly MOPP/ABV) with or without radiotherapy for Hodgkin's or non-Hodgkin's lymphoma. Inhibin A immunoactivity developed by Nigel Groome was measured by an enzyme-linked immunoadsorbent assay (ELISA) commercial kit (Serotec). RESULTS: Whereas all but one (40 years of age) of the surviving patients in the GnRH-a/chemotherapy co-treatment group resumed spontaneous ovulation and menses within 6 months, only one half of the patients in the "control" group (chemotherapy without GnRH-a co-treatment) resumed ovarian function and regular cyclic activity (P < 0.05). The remaining 50% experienced premature ovarian failure (POF). Temporarily increased FSH concentrations were experienced by approximately one third of the patients resuming cyclic ovarian function, suggesting a reversible ovarian damage in a larger proportion of women than those experiencing POF. The inhibin A immunoactive concentrations decreased during the GnRH-a/chemotherapy co-treatment but increased to normal levels in patients who resumed regular ovarian cyclicity, and/or spontaneously conceived, as compared to low levels in menopausal women and those who had developed POF. CONCLUSIONS: If these preliminary data are consistent in a larger group of patients, inhibin A concentration may serve as a prognostic factor for predicting the resumption of ovarian function, in addition to the levels of FSH, LH, and E2.

Haptoglobin-related protein as a serum marker in malignant lymphoma.

A novel serum 21 kDa haptoglobin-related protein (Hpr) was investigated in patients with malignant lymphoma, to evaluate its correlation with clinical and histologic features at presentation and its possible role as a tumor marker for patient outcome. One hundred fifty eight serum samples were taken from 88 patients with non-Hodgkin's lymphoma (n=58) and Hodgkin's disease (n=30) at presentation and in the course of follow-up. Sera from 61 healthy volunteers served as normal controls. Serum Hpr levels in the lymphoma patients (median 430x10 u/ml, range 0-4000x10 ) were significantly higher than in the control group (median 68x10 u/ml, range 0-180x10 )(p=0.0001). Higher median Hpr values were detected in patients with advanced disease (p=0.013), "B" symptoms (p=0.029) and in males (p=0.053). There was also a significant correlation between Hpr and erythrocyte sedimentation rate (p=0.028). Serial determinations showed a significant decrease of the initial Hpr values obtained after treatment in 41 patients, 38 of whom achieved complete remission. In the follow-up period additional Hpr measurements were taken from 17 patients. Three of them eventually relapsed, and showed increased Hpr levels at the time of relapse. Hpr levels remained low in 11 of 14 patients who maintained complete remission, and increased in three. In conclusion, serum Hpr is a new serum tumor marker of potential use in the clinical setting of lymphoma.

Dexamethasone, etoposide, ifosfamide, and cisplatin as second-line therapy in patients with aggressive non-Hodgkin's lymphoma.

BACKGROUND: This study analyzed the long term results of a combination of dexamethasone, etoposide, ifosfamide, and cisplatin (DVIP) used at the study center as standard second-line combination therapy in patients with aggressive non-Hodgkin's lymphoma (NHL) after prior exposure to doxorubicin. METHODS: All drugs were given intravenously for 4 consecutive days. The maximum daily doses of etoposide, ifosfamide, and cisplatin were 75 mg/m2, 1200 mg/m2, and 20 mg/m2, respectively. The dexamethasone dose was 20 mg twice daily. Cycles were repeated every 3 weeks. RESULTS: Fifty-six patients were included in the study. Partial response was noted in 18 patients (32%) and complete response (CR) in 18 patients (32%). Pretreatment factors that predicted CR were CR with prior therapy (CR in 17 of 34 in patients with a recurrence vs. 1 of 21 in patients with primary refractory NHL) and age (CR in 12 of 25 patients age < or = 65 years vs. 6 of 31 patients age > 65 years). Median time to treatment failure (TTF) and median survival were 11.5 months and 30 months, respectively, for patients with a CR and 3.5 months and 8 months, respectively, for all patients. Five patients (9%) remained disease free for > 24 months. By multivariate analysis, age was the only independent prognostic factor for TTF, whereas age, serum lactate dehydrogenase, and number of extranodal sites were independent predictors for survival. Myelosuppression (median granulocyte nadir and median platelet nadir of 350/mm3 and 77,000/mm3, respectively) was the major toxicity. There was one possible drug-related death associated with myelosuppression. CONCLUSIONS: DVIP is a relatively safe salvage combination therapy in patients with aggressive NHL. Response to first-line therapy and age are the most important predictors for prognosis after the administration of DVIP. This regimen is highly active in patients with recurrent NHL, but relatively ineffective in patients with primary refractory NHL.

Serotonin decreases cytoskeletal and cytosolic glycolytic enzymes and the levels of ATP and glucose 1,6-bisphosphate in skin, which is prevented by the calmodulin antagonists thioridazine and clotrimazole.

Serotonin (5-hydroxytryptamine) is believed to play a pathogenic role in skin damage and various skin abnormalities; however, its mechanism of action remains unknown. We show here that intradermal injection of serotonin in rats induced a marked reduction in the activities of the glycolytic enzymes, phosphofructokinase (EC 2.7.1.11) and aldolase (EC 4.1.2.13), in both the cytoskeletal and cytosolic fractions from skin. Serotonin also decreased the levels of glucose 1,6-bisphosphate in skin, the powerful regulator of glucose metabolism. These serotonin-induced changes were accompanied by a marked decrease in ATP content in skin. All these pathological changes induced by serotonin were prevented by treatment with two structurally different calmodulin antagonists: thioridazine, an antipsychotic phenothiazine, or clotrimazole, from the group of the antifungal azole derivatives that were recently recognized as calmodulin antagonists. The present results suggest that calmodulin antagonists may be effective drugs in the treatment of skin damage under various pathological conditions and diseases in which serotonin levels are increased.

Human immune disorder arising from mutation of the alpha chain of the interleukin-2 receptor.

Profound cellular immunodeficiency occurs as the result of mutations in proteins involved in both the differentiation and function of mature lymphoid cells. We describe here a novel human immune aberration arising from a truncation mutation of the interleukin-2 receptor alpha chain (CD25), a subunit of the tripartite high-affinity receptor for interleukin 2. This immunodeficiency is characterized by decreased numbers of peripheral T cells displaying abnormal proliferation but normal B cell development. Extensive lymphocytic infiltration of tissues, including lung, liver, gut, and bone, is observed, accompanied by tissue atrophy and inflammation. Although mature T cells are present, the absence of CD25 does affect the differentiation of thymocytes. While displaying normal development of CD2, CD3, CD4, and CD8 expression, CD25-deficient cortical thymocytes do not express CD1, and furthermore they fail to normally down-regulate levels of the anti-apoptotic protein bcl-2.

Benign proliferative lesions mimicking recurrence of Hodgkin's disease.

Salvage treatment in patients with recurrent Hodgkin's disease is more effective when tumor burden is minimal. That is why more intensive follow-up strategies, including frequent imaging tests, have been recently developed for the detection of early relapse. However, as screening procedures become more sensitive, there is an increasing risk of false-positive results, demonstrating nonmalignant proliferative disorders. We describe three young patients who had lymphocyte-predominant or mixed-cellularity Hodgkin's disease and were in clinical complete remission for 2.5-3 years after a combined treatment with chemotherapy and radiation. Imaging tests revealed new gallium-avid lymphadenopathy in the chest in two cases. Pathologically enlarged pelvic lymph nodes were identified in another case, after a diagnosis of recurrent disease in axilla. Those findings were interpreted as relapse, and the patients underwent thoracotomy and laparotomy, respectively, for histologic confirmation. The results showed progressively transformed germinal centers and sarcoid-like lesions, two benign proliferative disorders. When patients with Hodgkin's disease in remission show new lymphadenopathy, even with positive gallium scan, it seems mandatory to obtain tissue for histologic examination, even through invasive procedures such as laparotomy and thoracotomy, to avoid wrong diagnosis and unnecessary treatment.

An interleukin-2 receptor gamma chain mutation with normal thymus morphology.

One of the most common human immunodeficiencies is an X-linked condition arising from mutations of the gamma subunit of the interleukin-2 receptor (IL-2Rgamma). The IL-2Rgamma protein is one chain of the heterotrimeric (alpha, beta, gamma) IL-2 receptor, but also participates in the formation of the IL-4, 7, 9, and 15 receptor complexes. The diagnosis of X-linked SCID is usually relatively simple due to the distinctive immunological presentation; IL-2Rgamma-deficient patients typically lacking mature T lymphocytes (T-B+). However, it is becoming clear that this merely represents one extreme of a potential range of clinical presentations. We describe here a novel mutation of the human IL-2Rgamma chain (R222C) resulting in an unusual immunological phenotype. Although clinically immunodeficient, this patient has normal numbers of peripheral T and B cells, responds normally to mitogenic stimuli, and unusually, has a normal thymus gland. This IL-2Rgamma mutation is distinctive in that the protein is sufficiently stable to be expressed at the cell surface. While the T cell receptor repertoire appears complete, suggesting normal T cell differentiation occurs, patient T cells demonstrate a reduced ability to bind IL-2 and this appears sufficient to cause a deficiency in their ability to participate in antigenic responses. Early clinical recognition of this phenotype is critical as a delay in diagnosis may result in a fatal infection.

Prevention of irreversible chemotherapy-induced ovarian damage in young women with lymphoma by a gonadotrophin-releasing hormone agonist in parallel to chemotherapy.

To examine whether the concomitant administration of a gonadotrophin-releasing hormone agonist (GnRHa) during combination chemotherapy to young women with lymphoma may facilitate preservation of gonadal function, a prospective clinical protocol was undertaken in 18 cycling women with lymphoma, aged 15-40 years. Thirteen patients suffered from Hodgkin disease (HD) and 5 from non-Hodgkin lymphoma. After informed consent a monthly injection of depot D-TRP6-GnRHa was administered for a maximum of 6 months starting prior to chemotherapy. Most of these patients (15/18) were treated with the MOPP/ABV(D) combination chemotherapy followed by mantle field irradiation in 10 patients. Hormonal profile [luteinizing hormone (LH), follicle stimulating hormone (FSH), oestradiol, testosterone, progesterone, insulin-like growth factor (IGF)-1, prolactin] was taken before the GnRHa/chemotherapy co-treatment, and monthly thereafter until resuming spontaneous ovulation and menses. This group of prospectively treated lymphoma patients was compared to a matched control group of 18 women (aged 17-40 years) who have been treated with chemotherapy, mostly MOPP/ABV (14/18), with (11) or without (7) mantle field radiotherapy. Fourteen had Hodgkin's and four non-Hodgkin's lymphoma. Gonadal function was determined clinically, hormonally (LH, FSH, oestradiol, progesterone), and sonographically. Two of the patients in each group died from refractory disease. Of the remaining 16 patients, 15 (93.7%) resumed spontaneous ovulation and menses within 3-8 months of termination of the combined chemotherapy/GnRHa co-treatment. In contrast, only seven (39%) of the 18 similarly treated patients in the control group (chemotherapy without GnRHa) resumed ovarian cyclic activity (regular menses). The other 11 experienced premature ovarian failure (POF) (61%). Out preliminary data suggest a possible significant protective effect of GnRHa co-treatment with chemotherapy from irreversible ovarian damage (POF).

Inhibition of acute lymphoblastic leukaemia by a Jak-2 inhibitor.

Acute lymphoblastic leukaemia (ALL) is the most common cancer of childhood. Despite the progress achieved in its treatment, 20% of cases relapse and no longer respond to chemotherapy. The most common phenotype of ALL cells share surface antigens with very early precursors of B cells and are therefore believed to originate from this lineage. Characterization of the growth requirement of ALL cells indicated that they were dependent on various cytokines, suggesting paracrine and/or autocrine growth regulation. Because many cytokines induce tyrosine phosphorylation in lymphoid progenitor cells, and constitutive tyrosine phosphorylation is commonly observed in B-lineage leukaemias, attempts have been made to develop protein tyrosine kinase (PTK) blockers of leukaemia cell growth. Here we show that leukaemic cells from patients in relapse have constitutively activated Jak-2 PTK. Inhibition of Jak-2 activity by a specific tyrosine kinase blocker, AG-490, selectively blocks leukaemic cell growth in vitro and in vivo by inducing programmed cell death, with no deleterious effect on normal haematopoiesis.

Functional platelet-derived growth factor-beta (PDGF-beta) receptor expressed on early B-lineage precursor cells.

Growth and maturation of B lymphocytes from stem cells require a series of complex processes that are dependent at least in part on growth factors. Uncontrolled expression of receptors from these early growth factors may contribute to a leukaemogenesis of such early B cell progenitors. We show here that early pre-pre-B cells, but not mature B cells, express the PDGF receptor-beta (PDGFR-beta). These receptors contain a protein tyrosine kinase domain which is activated upon ligation with PDGF in pre-pre-B cells. Further, pre-pre-B leukaemia cells seem to express more PDGFR-beta compared with their normal counterparts, suggesting a role for these receptors in growth promotion of leukaemia cells.

Intermediate and high-grade gastric non-Hodgkin's lymphoma: a prospective study of non-surgical treatment with primary chemotherapy, with or without radiotherapy.

The role of surgery as initial treatment in gastric lymphoma remains controversial. We have prospectively evaluated a stomach conservation strategy in histologically aggressive gastric lymphoma, using primary adriamycin-containing chemotherapy, followed by involved-field radiotherapy in patients with limited disease. Twenty-six patients (median age 69 years) were entered in this study; 15 had stage I disease, 7 had stage II disease and 4 had stage IV disease. The chemotherapy combinations were CHOP (18 patients) and ProMACE/MOPP (8 patients). Radiotherapy was given to 11 patients. Of the 24 patients evaluated for response, 18 (75%) achieved endoscopically-confirmed complete response and 4 (17%) partial response. During follow-up (median 22 months), none of the complete responders developed recurrent lymphoma. Gastric resection was performed in 1/26 patients who did not respond to primary chemotherapy. There were no cases of perforation, but three patients (12%) developed acute gastro-intestinal bleeding a few days after the onset of chemotherapy, one of whom required a surgical devascularization procedure. There was no treatment-related mortality. These data further support the non-surgical approach in histologically aggressive gastric lymphoma, using primary chemotherapy with or without radiation therapy.

Full dose CHOP chemotherapy in elderly patients with non-Hodgkin's lymphoma.

Twenty-eight previously untreated elderly patients (median age 73 years, range 65-88) with aggressive non-Hodgkin's lymphoma were treated with full-dose CHOP chemotherapy between 1989 and 1992. The median of the average relative dose intensity (ARDI) was calculated for the initial cycles needed to achieve a maximal response or to determine progression of disease (1-6 cycles, median 4), as well as for the whole treatment course. For patients aged 65-74, both ARDIs were 0.89. A comparable group of 36 elderly patients who received reduced doses of CHOP from the start, served as a historical control. There was an increase of 11% and 29% in the ARDIs of the full-dose CHOP as compared with the reduced CHOP, in the initial cycles and for the whole treatment course respectively. Grade III-IV leukopenia was the main toxicity observed in 57% of the patients, and 7 patients were hospitalized for fever and leukopenia. There was no treatment-related death. It is concluded that CHOP chemotherapy without initial dose reduction is feasible in patients aged 65-74 years, resulting in high actual dose intensity with a reasonable degree of toxicity.