Granuloma formation and parasite disintegration in porcine cysticercosis: comparison with human neurocysticercosis

Taenia solium cysticerci infect human beings and pigs, causing cysticercosis. In this study the pig was used as a model to characterize the immune response against cysticerci, given the difficulties in analysing the developing immune response in infected human brains. Metacestodes in different stages of viability or degeneration were isolated from the brain, heart and skeletal muscle of naturally infected swine, and the adjacent tissue was examined histologically. The immune response elicited by the cysticerci was classified into four separate stages. In stage I the parasites were surrounded by a thin layer of collagen type I, and by stage II there was a sparse inflammatory infiltrate. In stage III, granuloma formation was evident, and by stage IV the parasite was surrounded by an eosinophil-rich infiltrate and its vesicular membrane had begun to degenerate. The final stage, IV, was detected mainly in the heart but not in the brain. The granulomatous reaction in swine resembled that described previously in human patients, but differed in the abundance of eosinophils, the relative paucity of plasma cells, and the discrete deposition of collagen. These differences were probably due to the fact that in pigs the immune response can be examined earlier than in human patients, in whom sampling is inevitably made at a more chronic stage.

Increased conventional chemotherapy does not improve survival in multiple myeloma: long-term results of two PETHEMA trials including 914 patients

BACKGROUND

Melphalan and prednisone (MP) has been the standard treatment for multiple myeloma (MM) for the last 30 years. Combination chemotherapy at conventional doses has not shown a significant prolongation of survival when compared to MP. There are few data comparing conventional chemotherapy at standard doses with conventional treatment at higher doses. We present the long-term outcome of 914 patients from two randomized trials comparing three different dose intensity regimens.

METHODS

From 1 January, 1985 to 31 December, 1989, 487 patients were randomized between MP (melphalan 9 mg/m(2) p.o. and prednisone 60 mg/m(2) days 1-4) and alternating VCMP (vincristine 1 mg i.v. on day 1, cyclophosphamide 500 mg/m(2) i.v. on day 1, melphalan 6 mg/m(2) p.o. on days 1-4, and prednisone 60 mg/m(2) on days 1-4) and VBAP (vincristine 1 mg i.v. on day 1, BCNU and doxorubicin 30 mg/m(2) i.v. each on day 1, and prednisone 60 mg/m(2) on days 1-4). From 1 January, 1990 to 31 May, 1994, 427 patients were randomized between VCMP/VBAP at the above detailed doses (VCMP/VBAP 'SD') and the same regimen increasing the doses of cyclophosphamide and doxorubicin from 500 to 1200 mg/m(2) and from 30 to 50 mg/m(2), respectively (VCMP/VBAP 'HD').

RESULTS

Increasing dose intensity produced a significantly higher partial response rate (31% vs 45% vs 51% for MP, VCMP/VBAP 'SD', and VCMP/VBAP 'HD', respectively; P < 0.01). However, a significantly early death rate was observed in the HD arm (7.7, 7.5 and 12.1% for MP, VCMP/VBAP 'SD', and VCMP/VBAP 'HD', respectively; P = 0.05). Median duration of response (20 vs 18 vs 19 months for MP, VCMP/VBAP 'SD', and VCMP/VBAP 'HD', respectively; P = NS) and median survival (25 vs 31 vs 29 months for MP, VCMP/VBAP 'SD', and VCMP/VBAP 'HD', respectively; P = NS) were similar in the three groups. MP produced a higher degree of thrombocytopenia than combination chemotherapy at standard (P = 0.002) or high dose (P = 0.01), this leading to a significantly higher dose reduction in the MP arm (P < 0.001 and P = 0.003 for VCMP/VBAP 'SD' and VCMP/VBAP 'HD', respectively).

CONCLUSION

In these trials the response rate significantly correlated with the regimen intensity. However, no significant differences in response duration and survival were found. This highlights the limited role of conventional chemotherapy in MM and the need for further trials, aimed at determining the impact of new treatment approaches such as high-dose therapy/autotransplantation.

The human nervous tissue in proximity to granulomatous lesions induced by Taenia solium metacestodes displays an active response

In neurocysticercosis, the nervous tissue surrounding the brain lesion is affected as a consequence of the local immune response induced by a Taenia solium metacestode. In this study, a histological and immunohistochemical analysis of five brain specimens from patients with neurocysticercosis revealed a proinflammatory activity reflected by an apparently altered blood-brain barrier permeability, secretion of pro-inflammatory cytokines, and up-regulation of molecules associated with antigen presentation. There were also anti-inflammatory cytokines, as well as an active wound-healing process reflected by angiogenesis, collagen deposition and glial scar formation. This immune response displayed by the nervous tissue adjacent to chronic neurocysticercosis lesions appeared to be contributing to the local tissue damage, and hence, may be fundamental in the pathology of NCC.

A cytotoxic diarylheptanoid from Viscum cruciatum

A diarylheptanoid, 1,7-di-(3',4'-dihydroxyphenyl)-4-hepten-3-one, hirsutanone, has been isolated from the methanolic extract of the aerial parts of Viscum cruciatum (Viscaceae) and characterized by spectroscopic methods and chemical transformations. This compound showed cytotoxic activity against melanoma (UACC-62), renal (TK-10) and breast (MCF-7) cancer cell lines.

Brain granulomas in neurocysticercosis patients are associated with a Th1 and Th2 profile

Neurocysticercosis (NCC) is a common central nervous system (CNS) infection caused by Taenia solium metacestodes. Despite the well-documented importance of the granulomatous response in the pathogenesis of this infection, there is limited information about the types of cells and cytokines involved. In fact, there has been limited characterization of human brain granulomas with any infectious agent. In the present study a detailed histological and immunohistochemical analysis of the immune response was performed on eight craniotomy specimens where a granuloma surrounded each T. solium metacestode. The results indicated that in all the specimens there was a dying parasite surrounded by a mature granuloma with associated fibrosis, angiogenesis, and an inflammatory infiltrate. The most abundant cell types were plasma cells, B and T lymphocytes, macrophages, and mast cells. Th1 cytokines were prevalent and included gamma interferon, interleukin-18 (IL-18), and the immunosuppressive, fibrosis-promoting cytokine transforming growth factor beta. The Th2 cytokines IL-4, IL-13, and IL-10 were also present. These observations indicate that a chronic immune response is elicited in the CNS environment with multiple cell types that together secrete inflammatory and anti-inflammatory cytokines. In addition, both collagen type I and type III deposits were evident and could contribute to irreversible nervous tissue damage in NCC patients.

Pharmacological effects of elenoside, an arylnaphthalene lignan

Acute toxicity (24 h) and general behavior in mice of a lignan from Justicia hyssopifolia, a beta-D-glucoside (elenoside), was studied, and the cytotoxic activity was performed. Elenoside (arylnaphthalene lignan) in mice showed a moderate toxicity order (305 mg/kg) and central depressive properties at doses of 25, 50, and 100 mg/kg. It also displayed cytotoxic activity in a range of concentration of 10(-5)-10(-4) M when studied in the human tumor cell line panel of the US National Cancer Institute (NCI). The results indicated that elenoside has central depressant effects, and the cytotoxic activity of elenoside suggests that this compound and its genin derivatives merit further investigation as antitumoral drugs.

General behavior, toxicity, and cytotoxic activity of elenoside, a lignan from Justicia hyssopifolia

Cytotoxicity, acute toxicity, and general pharmacological effects in mice of an arylnaphthalene lignan isolated from Jisticia hyssopifolia were studied. Elenoside was cytotoxic to human cancer cell lines in a range of concentrations from 10(-5) to 10(-4)M. It has an LD(50), ip in mice, of 305 mg/kg and central depressive properties at doses of 25, 50, and 100 mg/kg. Thus, elenoside appears to be a sedative with broad spectrum cytotoxicity.

[Impact of an anti-hepatitis B virus (HBV) immunization program in patients undergoing dialysis in Havana, Cuba]

The follow-up of HBV markers in selected high infection risk populations, in patients from the hemodialysis and peritoneal dialysis services was used to assess the effectiveness of a special vaccination program. Viral infection markers were studied in prevalence cross sections of the whole population of patients, and also by recording the reports of clinical cases of hepatitis B occurred during that period in those groups of patients. The prevention program consisted of the vaccination of all patients negative to the viral markers and the indication of vaccination for the new cases during the period of the kidney disease, just before the start of the treatment at the hemodialysis unit; besides all the persons susceptible to infection that had already been included in the program, regardless of the stage of the disease. The results show the benefit of the vaccination in these patients, but it is more effective in the period before the treatment with dialysis where there is a lower possibility of being exposed to the virus and the immune system is still competent. Once the program was established, after a follow up o 6 years, there have been no reports of new cases of hepatitis B and the incidence of the disease has been declining.

Cardiovascular activity of a methanolic extract of Digitalis purpurea spp. heywoodii

The paper deals with the effects of a glycosidal extract of Digitalis heywoodii, ssp. of Digitalis purpurea L., (Schrophulariaceae) grown in Badajoz (Spain), on isolated cardiac auricle of rabbits, urinary excretion of rats, as well as its emetic effect in pigeons. These effects using vehicle (propylene glycol-ethanol-water, 40:10:50) and digoxin as standards are presented. The extract at concentrations of 20 and 40 microg/ml produced an increase in the contraction force of auricles in a dose-dependent way. At doses of 15 and 30 mg/kg a slight diuretic and natriuretic effect was observed. The active dose range for emesis was 0.5-4 mg/kg and a decrease of the emesis time within 10 min of injection in dose-dependent manner was obtained. The pharmacological activity of the extract is related to gitoxin derivatives (digitalinum verum and strospeside), the most abundant compounds obtained from the leaves of Digitalis purpurea spp. heywoodii.

Fibrotic sequelae in pulmonary paracoccidioidomycosis: histopathological aspects in BALB/c mice infected with viable and non-viable paracoccidioides brasiliensis propagules

Patients with paracoccidioidomycosis often present pulmonary fibrosis and exhibit important respiratory limitations. Based on an already established animal model, the contribution of viable and non-viable P. brasiliensis propagules to the development of fibrosis was investigated. BALB/c male mice, 4-6 weeks old were inoculated intranasally either with 4x10(6) viable conidia (Group I), or 6. 5x10(6) fragmented yeast cells (Group II). Control animals received PBS. Six mice per period were sacrificed at 24, 48, 72h (initial) and 1, 2, 4, 8, 12 and 16 weeks post-challenge (late). Paraffin embedded lungs were sectioned and stained with H&E, trichromic (Masson), reticulin and Grocot&tacute;s. During the initial period PMNs influx was important in both groups and acute inflammation involving 34% to 45% of the lungs was noticed. Later on, mononuclear cells predominated. In group I, the inflammation progressed and granulomas were formed and by the 12th week they fussed and became loose. Thick collagen I fibers were observed in 66.6% and 83.3% of the animals at 8 and 12 weeks, respectively. Collagen III, thick fibers became apparent in some animals at 4 weeks and by 12 weeks, 83% of them exhibited alterations in the organization and thickness of these elements. In group II mice, this pattern was different with stepwise decrease in the number of inflammatory foci and lack of granulomas. Although initially most animals in this group had minor alterations in thin collagen I fibers, they disappeared by the 4th week. Results indicate that tissue response to fragmented yeast cells was transitory while viable conidia evoked a progressive inflammatory reaction leading to granuloma formation and to excess production and/or disarrangement of collagens I and III; the latter led to fibrosis.

A novel factor produced by placental cells with activity against HIV-1

The factors controlling the dynamics of HIV-1 transmission from mother to infant are not clearly known. Previous studies have suggested the existence of maternal and placental protective mechanisms that inhibit viral replication in utero. Preliminary studies from our laboratory revealed that supernatant from placental stromal cells protected HIV-1-infected PBMC from virus-induced apoptosis and suppressed virus production. We have attempted to characterize the antiviral activity of this placental factor (PF) and delineate the stages of HIV-1 replication affected. This activity was not due to the presence of any known cytokine reported to have anti-HIV effect. Direct exposure to PF had no suppressive effect on the infectivity of cell-free HIV-1, and envelope-mediated membrane fusion appeared to be unaffected. Western blot analysis of HIV-1 from infected PBMC treated with PF revealed that expression of all viral proteins was reduced proportionately, both intracellularly and in released virions. However, exposure of HIV-1-infected cells to PF resulted in production of virions with 10-100-fold-reduced infectivity. PF-treated virions contained two- to threefold reduced ratios of cyclophilin A:Gag protein as compared with untreated virus. Reduced cyclophilin A content resulting in decreased binding of cyclophilin A to Gag could account, in part, for the observed reduction in infectivity. Our results suggest that placental cells produce an antiviral factor that protects the fetus during gestation and may have therapeutic potential.

[Validation of a ultramicroELISA for detecting antibodies against hepatitis B surface antigen]

The results of a validation study of the ultramicroanalitical assay for the detection of antibodies against the hepatitis B surface antigen (UMELISA anti-HBsAg), which was carried out by comparing the results obtained with the Hepanostika anti-HBsAg, commercial diagnosis kit are presented. For this purpose, sera from the clinical assays of the Cuban recombinant vaccine against hepatitis B were used. With the first sera group (n = 30) it was obtained, 93.1% of sensitivity, 98.5% of specificity and a concordance of 94.3%. The correlation coefficient showed a similar trend of the results (p < 0.01) and no significant differences were found in the average geometrical titre (TPG) between both assays (p > 0.05). With the second group (n = 100), whose assays were carried out at the "Pedro Kouri" Institute of Tropical Medicine (PKI) and at the Immunoassay Center (IAC) simultaneously, it was observed a sensitivity of 96.25% in both centers, a specificity of 75% at the PKI and of 90% at the IAC, and a coincidence of 92% and 95%, respectively. The correlation coefficient presented similar values and there were no significant differences between the TPG obtained by the two methods (p > 0.05). The results attained show in general the validity of the new assay and the feasibility to put it into practice either for following up the infection, or for carrying out clinical assays of vaccine evaluations.

Galphimine-B modifies electrical activity of ventral tegmental area neurons in rats

Galphimine-B (G-B) is a bioactive compound isolated from the plant Galphimia glauca Cav. (Malpighiaceae) with central nervous system depressant properties previously described. In the present study, extracellular spiking activity records in either somatosensorial cortex or ventral tegmental area (VTA) neurons, were performed in rats after i.p. or local administration of G-B. None of the cortical neurons displayed significant changes induced by any of the applied doses. In VTA cells, two patterns of electrical discharge were recorded, bursting (57%) and nonbursting (43%) types. Systemic administration of G-B induced excitatory effects in neurons with a bursting firing pattern and mixed responses on nonbursting units. When this compound was applied locally by microiontophoresis, most of the bursting and nonbursting spiking neurons showed a firing depression and only a few of the nonbursting neurons showed an increment of discharge frequency. These results are important since VTA is a major dopaminergic center responsible for the innervation of the prefrontal cortex, nucleus accumbens and entorhinal region. These areas are targets for the action of antipsychotic drugs.

Computerized endoscopic surgical grasper

We report a computerized endoscopic surgical grasper with computer control and a force feedback (haptic) user interface. The system uses standard unmodified grasper shafts and tips. The device can control grasping forces either by direct surgeon control, via teleoperation, or under software control. In this paper, we test an automated palpation function in which the grasper measures mechanical properties of the grasped tissue by applying a programmed series of squeezes. Experimental results show the ability to discriminate between the normal tissues of small bowel, lung, spleen, liver, colon, and stomach. We anticipate applications in telesurgery, clinical endoscopic surgery, surgical training, and research.

Osteogenesis imperfecta and coronary artery surgery. A case report

A new case of Osteogenesis Imperfecta (OI) suffering ischemic heart disease is reported. The patient was successfully operated on in our Institution and the bibliographic search showed only another case of such an association of diseases successfully treated by surgery. This patient proves that coronary artery surgery procedures are possible when OI complicates the cardiac ischemic syndrome.

Survival of multiple myeloma patients who are potential candidates for early high-dose therapy intensification/ autotransplantation and who were conventionally treated

PURPOSE

To analyze the outcome of patients with multiple myeloma (MM) who were potential candidates for early high-dose therapy (HDT) intensification followed by autotransplantation from a series treated with conventional chemotherapy.

PATIENTS AND METHODS

From January 1985 through December 1989, 487 patients with symptomatic MM were entered onto a randomized study to compare melphalan and prednisone (MP) versus vincristine, cyclophosphamide, melphalan, and prednisone (VCMP) /vincristine, carmustine (BCNU), doxorubicin, and prednisone (VBAP). The sub-group of 77 patients who could have been candidates for early intensification with HDT followed by stem-cell support (ie, < 65 years of age, stage II or III disease, performance status < 3, and objective or partial response to initial chemotherapy) are the subjects of this report.

RESULTS

Seventy-seven of 487 patients could have been candidates for early intensification. The median age was 56 years (range, 27 to 64). At diagnosis, 12% had abnormal renal function, 16% hypercalcemia, and 42% serum beta 2-microglobulin level > or = 6 mg/L; 62% had stage III disease at diagnosis. Thirty-six patients were initially treated with MP and 41 with VCMP/VBAP. The median response duration to initial chemotherapy was 22 months, and the actuarial probability of being in continued first response at 5 years was 14%. After a median follow-up time of 58 months, 59 patients have died, one was lost to follow-up evaluation, and 17 are still alive 69 to 119 months after initial chemotherapy. The median survival time from initiation of treatment was 60 months and from the time when autotransplantation would be considered, 52 months. The only independent prognostic parameter for survival was renal function at diagnosis.

CONCLUSION

The median survival time of patients with MM who are less than 65 years of age and who respond to initial chemotherapy is 5 years. This survival duration is similar to that reported in selected series of patients given early HDT and stresses the importance of ongoing randomized trials to determine the role of HDT in the treatment of younger myeloma patients.

Antiulcerogenicity of the flavonoid fraction from Erica andevalensis Cabezudo-Rivera

Investigations were carried out to determine the antiulcerogenicity of the flavonoid fraction (ethyl acetate extract) of Erica andevalensis Cabezudo-Rivera on gastric ulceration induced by different experimental models. Oral treatment with the ethyl acetate extract and the major flavonoid (myricetin 3-O-D-galactoside) were found to be effective to prevent gastric ulceration induced by cold-restraint stress in rats. Statistically significant ulcer index values with respect to the control group were observed. Mucus content was not increased although it was accompanied by an increase in proteins and hexosamines. In pyloric-ligated animals flavonoids showed a significant reduction in the number and severity of the ulcers. Under the same conditions acidity did not decrease with the flavonoid extract and myricetin 3-O-D-galactoside significantly as compared to control. Gastric ulcers induced by oral administration of absolute ethanol were reduced by pretreatment with the flavonoid extract of doses from 125 to 250 mg/kg and the isolated flavonoid of 25 mg/kg p.o. However neither the flavonic extract nor the isolated flavonoid induced changes in the amount and glycoprotein content of gastric mucus.

Association of intravenous phenytoin toxicity with demographic, clinical, and dosing parameters

Previous studies investigating intravenous phenytoin toxicity have been largely anecdotal, and have inferred an association with older patients, cardiovascular disease, and higher doses, concentrations, and infusion rates of phenytoin. This investigation sought to elucidate both the incidence and nature of acute intravenous phenytoin toxicity in emergency department patients, and to identify any demographic, clinical, or dosing associations with toxicity, by analyzing a retrospective case series over 3 years in a municipal teaching hospital. A consecutive series of 164 patients who received intravenous phenytoin loading in the emergency department following acute seizure presentation was identified. Demographic, clinical, and dosing data were collected, and the nature of toxicity was noted. Data were then analyzed statistically for potential associations with toxicity. Eight cases of hypotension and no apnea or arrhythmias were noted in the 164 patients (4.9% incidence). Analysis of demographic, clinical, and dosing data found statistically significant associations between hypotension and both a lower phenytoin dose administered (537 mg in hypotensive patients v 787 mg in normotensive patients, P = .00046) and the presence of abnormal neurological signs at initial presentation (20% incidence when abnormal signs present v 3.5% incidence when absent, P = .026). No other associations were found between toxicity and other variables. This sample size could detect differences ranging from 4% to 11% in complication rate (hypotension) for the various demographic, clinical, and dosing parameters with a statistical power of 80%. It was concluded that the incidence of hypotension from intravenous phenytoin administration in this study population was approximately 5%, and the incidence of apnea and cardiac arrhythmia in this series was 0%. No associations with age, comorbidities, or infusion rates were found, in contrast to other studies. Association of intravenous phenytoin toxicity with lower phenytoin dose is likely related to prompt cessation of the drug once signs of toxicity occur. The possible association of toxicity with abnormal initial neurological signs has not previously been reported and may possibly define a population at risk if validated by prospective research in additional populations.

Antifertility effects of (+)-S-2-amino-6-iodoacetamidohexanoic acid (2-AIHA) in female rats

(+)-S-2-amino-6-iodoacetamidohexanoic acid (AIHA), an irreversible inhibitor of the ornithindecarboxylase and extrahepatic arginase enzymatic activities with antineoplasic properties, was evaluated for antifertility activity in pregnant rats by oral administration at different periods of gestation. Our results showed that doses of 10 and 20 mg/kg of AIHA orally administered produced a contraceptive effect when it was administered from days 2 to 5, and 8 to 12 of gestation, respectively. The gestation time was slightly shortened when AIHA was applied from day 15 until labor. No sign of external malformations in fetuses was observed. On the other hand, AIHA did not affect the total length of oestrous cycle at the same dosage level used to interrupt pregnancy. In ovariectomized immature rats, neither changes in uterine weight, premature vaginal opening, or cornified cells were found. However, AIHA enhanced the estradiol-induced increase in uterine weights when both were concomitantly administered.

Monounsaturated fatty acid-enriched diet decreases plasma plasminogen activator inhibitor type 1

An increase in levels of plasma plasminogen activator inhibitor type 1 (PAI-1) is one of the main hemostatic alterations in patients with coronary heart disease. Despite growing interest in the fibrinolytic system, few studies have been undertaken to determine the effect exerted on it by the different dietary fatty acids. We investigated the effect of a monounsaturated fat (MUFA)-rich diet in comparison with a low-fat diet (National Cholesterol Education Program step 1 diet) (NCEP-1) on factors involved in blood coagulation and fibrinolysis. We also determined the effect of dietary cholesterol on these blood parameters. Twenty-one young, male, healthy volunteers followed two low-fat/high-carbohydrate diets (< 30% fat, < 10% saturated fat, 14% MUFA) for 24 days each, with 115 or 280 mg of cholesterol per 1000 kcal per day, and two oleic acid-enriched diets (38% fat, 24% MUFA) with the same dietary cholesterol as the low-fat/high-carbohydrate diets. Plasma levels of fibrinogen, thrombin-antithrombin complexes, prothrombin fragments 1+2, plasminogen, alpha 2 antiplasmin, and tissue plasminogen activator were not significantly different among the experimental diets used in this study. Consumption of the diet rich in MUFA resulted in a significant decrease in both PAI-1 plasma activity (P < .005) and antigenic PAI-1 (P < .04) compared with the carbohydrate-rich diet (NCEP-1). The addition of dietary cholesterol to each of these diets did not result in any significant additional effect. Changes in insulin levels and PAI-1 activity were positively correlated (r = .425; P < .02). In conclusion, consumption of diets rich in MUFAs decreases PAI-1 plasma activity, which is accompanied by a parallel decrease in plasma insulin levels.

Diuretic action of an aqueous extract of Lepidium latifolium L

An aqueous extract of Lepidium latifolium L. given orally and intraperitoneally considerably enhanced urinary excretion (UV) in rats with respect to control groups. A slight increase in ion excretion was also observed. Other parameters such as specific gravity, nitrite, pH, glucose, ketone bodies, urobilinogen, and blood were also studied. A good correlation for the dosage rat/man for the aqueous extract was achieved.

Detection of minimal residual disease by polymerase chain reaction of bcr/abl transcripts in chronic myelogenous leukaemia following allogeneic bone marrow transplantation

The prognostic significance of detecting minimal residual disease by polymerase chain reaction (PCR) amplification of bcr/abl mRNA transcripts was investigated in 27 bone marrow samples from 20 patients with Philadelphia chromosome (Ph1) positive chronic myelogenous leukaemia (CML) in complete cytogenetic remission following allogeneic bone marrow transplantation. Sixteen were transplanted in first chronic phase, two were in second chronic phase, one was in accelerated phase and one was in blast crisis. All 20 achieved complete cytogenetic remission post transplant and 15 patients had detectable bcr/abl mRNA by PCR from 2 to 22 months following the procedure. One of these patients had graft failure and one died from graft-versus-host-disease at 7 months. Of the remaining 13 PCR-positive patients, only one (8%) relapsed after 23 months; the other 12 were alive and still in remission after a median follow-up of 16+ months (ranging 5+ to 29+ months). Five patients were PCR negative; all are alive in complete clinical and cytogenetic remission at 10+, 11+, 19+, 25+ and 25+ months post transplant. In this study, detection of subclinical Ph1-positive cells by PCR was not associated with imminent clinical or cytogenetic relapse. Since late recurrence may potentially occur, long-term follow-up is required to definitely determine the prognostic value of the PCR assay.

Identification of breakpoints in t(8;21) acute myelogenous leukemia and isolation of a fusion transcript, AML1/ETO, with similarity to Drosophila segmentation gene, runt

We have developed a restriction map of the chromosome 21 breakpoint region involved in t(8;21)(q22;q22.3) acute myelogenous leukemia (AML) and have isolated a genomic junction clone containing chromosome 8 and 21 material. Using probes from these regions, rearrangements have been identified in each of nine cases of t(8;21) AML examined. In addition, we have isolated cDNA clones from a t(8;21) AML cDNA library that contain fused sequences from chromosome 8 and 21. The chromosome 8 component, referred to as ETO (for eight twenty-one), is encoded over a large genomic region, as suggested by the analysis of corresponding yeast artificial chromosomes (YACs). The DNA sequence of the chromosome 21 portion of the fusion transcript is derived from the normal AML1 gene. A striking similarity (67% identity over 387 bp, with a corresponding 69% amino acid identity) was detected between AML1 and the Drosophila segmentation gene, runt. The critical consequence of the translocation is the juxtaposition of 5' sequences of AML1 to 3' sequences of ETO, oriented telomere to centromere on the der(8) chromosome.

Clinical implications of decreased retinoblastoma protein expression in acute myelogenous leukemia

The retinoblastoma (RB) protein levels in blast-enriched mononuclear fractions from the peripheral blood of 33 newly diagnosed patients with acute myelogenous leukemia were studied. Ten patients who had previously been treated were also analyzed, nine of whom had achieved prior complete remission. Low RB protein expression was found in 13 of 43 (30%) of the acute myelogenous leukemia patients as determined by Western blotting and immunochemical analysis. Of particular interest among the 20 newly diagnosed patients treated with the same therapeutic regimen, the median survival was 39 days for those with low RB protein expression compared to 333 days for those with high levels of RB protein expression in their leukemic cells (P less than or equal to 0.02). This preliminary study suggests that decreases of RB protein expression in peripheral blood of myeloid leukemic cells occur frequently and may be associated with shortened survival of acute myelogenous leukemia patients.