Histomorphometric evaluation of implant design as a key factor in peri-implant bone response: a preliminary study in a dog model.

AIM: Primary implant stability as the establishment of a direct bone-to-implant contact (BIC) plays a major role in long-term successful implant osseointegration. Numerous factors influencing this initial stability have been studied. This preliminary in vivo study on a dog lower jaw aimed to investigate the hypothesis that primary implant stability in low density bone may be influenced by implant design. METHODS: The authors compared two different implant designs with regard to their immediate quantitative relation to host bone (BIC% and gap area, GA%). The screw-shaped implants, manufactured by Or-Vit (Castelmaggiore-Bologna, Italy), exhibited similar microroughness surface and two different thread pitches: ''narrow-pitch'' implants (NP) and ''wide-pitch'' implants (WP) with a 0.5 mm and 1.5 mm thread pitch respectively. Implants were placed in dog jaw after complete osseous healing of the extractive sockets, according to a delayed implantation procedure. Five hours after surgery the animal was sacrificed. Radiographic, histological, morphometric and ultrastructural analysis were performed. RESULTS: An inverse relation existed among the two parameters BIC and GA: GA, as a region with high osteogenetic potentiality, appeared wider in WP implants; BIC, as the expression of primary mechanical stability, was higher in NP implants. CONCLUSION: Based on this results, we could assume that NP implants might be the clinical choice in case of immediate loading.This single case study might be considered a starting point for further long term in vivo investigations aiming to establish the implant design that best favours osseointegration at different bone quality sites.

Therapeutic targeting of CK2 in acute and chronic leukemias.

CK2 is a ubiquitously expressed, constitutively active Ser/Thr protein kinase, which is considered the most pleiotropic protein kinase in the human kinome. Such a pleiotropy explains the involvement of CK2 in many cellular events. However, its predominant roles are stimulation of cell growth and prevention of apoptosis. High levels of CK2 messenger RNA and protein are associated with CK2 pathological functions in human cancers. Over the last decade, basic and translational studies have provided evidence of CK2 as a pivotal molecule driving the growth of different blood malignancies. CK2 overexpression has been demonstrated in nearly all the types of hematological cancers, including acute and chronic leukemias, where CK2 is a key regulator of signaling networks critical for cell proliferation, survival and drug resistance. The findings that emerged from these studies suggest that CK2 could be a valuable therapeutic target in leukemias and supported the initiation of clinical trials using CK2 antagonists. In this review, we summarize the recent advances on the understanding of the signaling pathways involved in CK2 inhibition-mediated effects with a particular emphasis on the combinatorial use of CK2 inhibitors as novel therapeutic strategies for treating both acute and chronic leukemia patients.

Characterization of T cell repertoire in patients with graft-versus-leukemia after donor lymphocyte infusion.

The clinical efficacy of donor lymphocyte infusions (DLI) in patients with relapsed chronic myelocytic leukemia after allogeneic bone marrow transplantation has been demonstrated in several recent studies. Although it is presumed that allogeneic T cells mediate this graft-versus-leukemia (GVL) effect, the influence of DLI on the T cell compartment of recipients has not been determined. To characterize the immunologic effects of DLI and to identify T cell changes selectively associated with the GVL response, we analyzed the T cell receptor (TCR) repertoire in four patients with relapsed chronic myelocytic leukemia who achieved a complete remission after infusion of CD4+ lymphocytes from HLA-identical sibling donors. Only one of the four patients developed clinically significant graft-versus-host disease (GVHD) after infusion of donor lymphocytes. TCR repertoire was examined after PCR amplification of 24 Vbeta gene subfamilies in serial samples obtained over a 1-yr period before and after DLI. Results were compared to 10 normal donors. Before DLI, all four patients were found to have abnormal TCR Vbeta repertoire in peripheral T cells, associated with a large number of clonal and oligoclonal patterns. Abnormal TCR patterns persisted for at least 3 mo after DLI, but thereafter gradually began to normalize. By 1 yr after DLI, all patients demonstrated almost complete normalization of Vbeta repertoire with polyclonal representation within almost all Vbeta gene subfamilies. We also examined changes in the TCR Vbeta repertoire associated with the disappearance of Ph+ cells. In each patient, we were able to identify the expansion of at least 1 Vbeta gene subfamily that coincided with the time of the cytogenetic response. In one patient who was studied in greater detail, CDR3 size analysis of serial samples after DLI indicated that these changes were associated with the appearance of clonal T cells. This finding was confirmed through CDR3 sequence analysis and use of CDR3 clone-specific oligonucleotide probes. A putative GVL clone identified by this technique was not detectable in either donor or patient T cells before DLI, but persisted in peripheral T cells for approximately 1 yr. These experiments therefore provide evidence for the clonal expansion of allogeneic T cells that may be selective mediators of antileukemia activity without also mediating graft-versus-host disease.

Characterization of a novel subset of CD8(+) T cells that expands in patients receiving interleukin-12.

IL-12 has significant antitumor activity in mice that may be mediated by CD8(+) T cells. We show in this report that repeated subcutaneous injections of IL-12 in patients with cancer resulted in the selective expansion of a subset of peripheral blood CD8(+) T cells. This T cell subset expressed high levels of CD18 and upregulated IL-12 receptor expression after IL-12 treatment in vivo. In normal subjects, these CD3(+)CD8(+)CD18(bright) T cells expressed IL-12 and IL-2 receptors and adhesion/costimulatory molecules to a greater degree than other CD8(+) and CD4(+) T cells. They appeared morphologically as large granular lymphocytes, although they did not express NK cell markers such as CD56. In addition, CD8(+)CD18(bright) T cells were almost exclusively T cell receptor (TCR) alphabeta+, and exhibited a TCR Vbeta repertoire that was strikingly oligoclonal, whereas the Vbeta repertoire of CD18(dim) T cells was polyclonal. Although CD8+CD18(bright) T cells demonstrated little functional responsiveness to IL-12 or IL-2 alone in vitro, they responded to the combination of IL-12+IL-2 with strong IFN-gamma production and proliferation and enhanced non-MHC-restricted cytolytic activity. In contrast, CD18(dim) T cells were not activated by IL-12 or IL-2, alone or in combination. These findings demonstrate that CD8+CD18(bright) T cells are a unique population of peripheral blood lymphocytes with features of both memory and effector cells that are capable of TCR-independent activation through combined stimulation with IL-12+IL-2. As this activation results in IFN-gamma production and enhanced cytolytic activity, these T cells may play a role in innate as well as acquired immunity to tumors and infectious pathogens. Additional studies will be necessary to determine whether CD8+CD18(bright) T cells mediate the antitumor effect of IL-12 or IL-2 administered to cancer patients, and if so, whether maximal activation of these T cells with the combination of IL-12+IL-2 in vivo can augment the clinical effectiveness of these cytokines.

Destination of titanium particles detached from titanium plasma sprayed implants.

Small titanium particles may detach from titanium plasma sprayed (TPS) implants during implant insertion, when no preliminary tapping is used, probably for the frictional force between titanium coating and host bone. Aim of this study was to investigate the destination of these titanium particles observed in the peri-implant environment. Twenty-four TPS screws were implanted in tibiae of two sheep. Fourteen and 90 days after implantation the implants with the surrounding bone were removed and processed to be analyzed by light microscope and scanning electron microscope (secondary electron and back-scattered electron probes). Small titanium particles detached from the unloaded TPS implants were observed both in the newly-formed bone matrix and in marrow tissue. Histomorphometric analysis showed that both at 14 and 90 days after implantation the titanium particles appeared more concentrated in marrow tissue than in calcified bone matrix, decreasing by 66.4% over time. In particular, smaller particles (<250 microm(2)) decreased by 81.5%, whereas the larger ones (250-2000 microm(2)) did not show any significant variations over time, suggesting that most of the smaller particles may undergo to ionic dissolution, probably migrating into the peri-implant marrow lacunae. A slight migration of titanium particles from the implant surface towards the more distant peri-implant tissues was also demonstrated over time.

Tendon crimps and peritendinous tissues responding to tensional forces.

Tendons transmit forces generated from muscle to bone making joint movements possible. Tendon collagen has a complex supramolecular structure forming many hierarchical levels of association; its main functional unit is the collagen fibril forming fibers and fascicles. Since tendons are enclosed by loose connective sheaths in continuity with muscle sheaths, it is likely that tendon sheaths could play a role in absorbing/transmitting the forces created by muscle contraction. In this study rat Achilles tendons were passively stretched in vivo to be observed at polarized light microscope (PLM), scanning electron microscope (SEM) and transmission electron microscope (TEM). At PLM tendon collagen fibers in relaxed rat Achilles tendons ran straight and parallel, showing a periodic crimp pattern. Similarly tendon sheaths showed apparent crimps. At higher magnification SEM and TEM revealed that in each tendon crimp large and heterogeneous collagen fibrils running straight and parallel suddenly changed their direction undergoing localized and variable modifications. These fibril modifications were named fibrillar crimps. Tendon sheaths displayed small and uniform fibrils running parallel with a wavy course without any ultrastructural aspects of crimp. Since in passively stretched Achilles tendons fibrillar crimps were still observed, it is likely that during the tendon stretching, and presumably during the tendon elongation in muscle contraction, the fibrillar crimp may be the real structural component of the tendon crimp acting as shock absorber. The peritendinous sheath can be stretched as tendon, but is not actively involved in the mechanism of shock absorber as the fibrillar crimp. The different functional behaviour of tendons and sheaths may be due to the different structural and molecular arrangement of their fibrils.

Therapeutic potential of targeting sphingosine kinases and sphingosine 1-phosphate in hematological malignancies.

Sphingolipids, such as ceramide, sphingosine and sphingosine 1-phosphate (S1P) are bioactive molecules that have important functions in a variety of cellular processes, which include proliferation, survival, differentiation and cellular responses to stress. Sphingolipids have a major impact on the determination of cell fate by contributing to either cell survival or death. Although ceramide and sphingosine are usually considered to induce cell death, S1P promotes survival of cells. Sphingosine kinases (SPHKs) are the enzymes that catalyze the conversion of sphingosine to S1P. There are two isoforms, SPHK1 and SPHK2, which are encoded by different genes. SPHK1 has recently been implicated in contributing to cell transformation, tumor angiogenesis and metastatic spread, as well as cancer cell multidrug-resistance. More recent findings suggest that SPHK2 also has a role in cancer progression. This review is an overview of our understanding of the role of SPHKs and S1P in hematopoietic malignancies and provides information on the current status of SPHK inhibitors with respect to their therapeutic potential in the treatment of hematological cancers.

Beneficial effects of intracoronary adenosine as an adjunct to primary angioplasty in acute myocardial infarction.

BACKGROUND: The benefits of vessel recanalization in acute myocardial infarction (AMI) are limited by reperfusion damage. In animal models, adenosine limits reperfusion injury, reducing infarct size and improving ventricular function. The aim of this study was to evaluate the safety and feasibility of adenosine adjunct to primary PTCA in AMI. METHODS AND RESULTS: Fifty-four AMI patients undergoing primary PTCA were randomized to intracoronary adenosine or saline. The 2 groups were similar for age, sex, and infarct location. Adenosine administration was feasible and well tolerated. PTCA was successful in all patients and resulted in TIMI 3 flow in all patients given adenosine and in 19 given saline (P<0.05). The no-reflow phenomenon occurred in 1 adenosine patient and in 7 saline patients (P=0.02). Creatine kinase was lower in the adenosine group, and a Q-wave MI developed in 16 adenosine patients and in 23 saline patients (P=0.04). Sixty-four percent of dyssynergic segments improved in the adenosine group and 36% in the saline group (P=0. 001). Function worsened in 2% of dysynergic segments in the adenosine group and in 20% in the saline group (P=0.0001). Adverse cardiac events occurred in 5 patients in the adenosine group and in 13 patients in the saline group (P=0.03). CONCLUSIONS: Intracoronary adenosine administration is feasible and well tolerated in AMI. Adenosine adjunct to primary PTCA ameliorates flow, prevents the no-reflow phenomenon, improves ventricular function, and is associated with a more favorable clinical course.

Adenosine causes the release of active renin and angiotensin II in the coronary circulation of patients with essential hypertension.

OBJECTIVES: The aim of the study was to evaluate whether adenosine infusion can induce production of active renin and angiotensin II in human coronary circulation. BACKGROUND: Adenosine can activate angiotensin production in the forearm vessels of essential hypertensive patients. METHODS: In six normotensive subjects and 12 essential hypertensive patients adenosine was infused into the left anterior descending coronary artery (1, 10, 100 and 1,000 microg/min x 5 min each) while active renin (radioimmunometric assay) and angiotensin II (radioimmunoassay after high performance liquid chromatography purification) were measured in venous (great cardiac vein) and coronary arterial blood samples. In five out of 12 hypertensive patients adenosine infusion and plasma samples were repeated during intracoronary angiotensin-converting enzyme inhibitor benazeprilat (25 microg/min) administration. Finally, in adjunctive hypertensive patients, the same procedure was applied during intracoronary sodium nitroprusside (n = 4) or acetylcholine (n = 4). RESULTS: In hypertensive patients, but not in control subjects, despite a similar increment in coronary blood flow, a significant (p < 0.05) transient increase of venous active renin (from 10.7 +/- 1.4 [95% confidence interval 9.4 to 11.8] to a maximum of 13.8 +/- 2.1 [12.2 to 15.5] with a consequent drop to 10.9 +/- 1.8 [9.7 to 12.1] pg/ml), and angiotensin II (from 14.6 +/- 2.0 [12.7 to 16.5] to a maximum of 20.4 +/- 2.7 [18.7 to 22.2] with a consequent drop to 16.3 +/- 1.8 [13.9 to 18.7] pg/ml) was observed under adenosine infusion, whereas arterial values did not change. Calculated venous-arterial active renin and angiotensin II release showed a strong correlation (r = 0.78 and r = 0.71, respectively; p < 0.001) with circulating active renin. This adenosine-induced venous angiotensin II increase was significantly blunted by benazeprilat. Finally, both sodium nitroprusside and acetylcholine did not affect arterial and venous values of active renin and angiotensin II. CONCLUSIONS: These data indicate that exogenous adenosine stimulates the release of active renin and angiotensin II in the coronary arteries of essential hypertensive patients, and suggest that this phenomenon is probably due to renin release from tissue stores of renally derived renin.

Biological fixation of endosseous implants.

Primary implant stability is ensured by a mechanical fixation of implants. However, during implant healing a biological anchorage is necessary to achieve final osseointegration. Aim of this study was to investigate the histological aspects of biological fixation around titanium screws. Forty-eight titanium screws with different surfaces (smooth, plasma sprayed, sand blasted) were inserted in tibiae and femura of sheep and analyzed by light microscope and SEM 1 hour, 14 and 90 days after implantation. One hour after implantation the implant-bone gap was filled with a blood clot and host bone chips arising from burr surgical preparation or friction during implant insertion. Fourteen days after implantation new trabecular bone and enveloped bone chips were observed in the gap: no osteogenesis developed where implant threads were in contact with host bone. Ninety days after surgery all trabecular bone and most of the bone chips were substituted by a mature lamellar bone with few marrow spaces. Our results suggest that the trabecular bone and bone chips represent a three-dimensional network ensuring a biological implant fixation in all different implant surfaces 2 weeks after surgery. Host bone chips could favour the peri-implant osteogenesis. Inter-trabecular and implant-trabecular marrow spaces of both trabecular and lamellar bone may favour the peri-implant bone turnover.

Adenosine-induced renal vasoconstriction in man.

OBJECTIVE: The aim of the study was to evaluate the effects of adenosine on renal blood flow in humans. METHODS: Eleven normotensive patients (mean age 53 +/- 11 years) with normal renal angiograms were enrolled in the study. Arterial blood pressure, one ECG lead and arterial renal blood flow velocity, by intravascular Doppler catheter, were monitored throughout the procedure. Incremental doses (10(-5), 10(-4), 10(-3), 2 x 10(-3), 5 x 10(-3), 10(-2), 10(-1), 1 mg) were selectively injected, at 5-min intervals, in a renal artery. RESULTS: Adenosine administration had no significant effects on blood pressure, heart rate and atrio-ventricular conduction. A progressive reduction in renal blood flow velocity (from 16.36 +/- 1.9 to 3.9 +/- 0.8 cm/s, P < 0.0001) was observed. Following adenosine the decrease of flow velocity was immediate and its duration was proportional to dosage (from 0.5 +/- 0.4 s at 10(-5) mg to 31 +/- 6.5 s at 1 mg). Renal angiography, repeated in four patients during flow velocity decrement, showed no changes in vessel diameter. CONCLUSIONS: Exogenous adenosine-induced a marked and transient reduction in renal blood flow in man. This effect suggests that adenosine or its metabolites may be directly implicated in rapid and powerful mechanisms of cardiac output redistribution. Thus endogenous adenosine could have a role in regulating renal blood flow in physiological and pathological situations like strenuous exercise, hemorrhage shock and cardiac failure.

Developmental approaches in immunological control of acute myelogenous leukaemia.

After many years of hope and disillusionment, the possibility of utilizing immune-mediated approaches to control neoplastic clones has become a reality in various haematological malignancies. This is largely a consequence of the continuous advances in knowledge and the progressive development of more refined technologies that have led to a better understanding of the biology of the malignant cells and of the host immune system, to a more precise definition of disease entities and to the design of innovative therapeutic programmes. In this chapter, we will review different immunological strategies that have reached clinical practice in patients with acute myelogenous leukaemia (AML), the focus of this volume, and discuss pre-clinical developments that may in the near future translate into the design of new immunotherapeutic protocols for the management of AML. Treatment of AML with antibody directed therapy will also be discussed.

A CD4+ T cell clone selected from a CML patient after donor lymphocyte infusion recognizes BCR-ABL breakpoint peptides but not tumor cells.

BACKGROUND: In patients with chronic myelocytic leukemia (CML), the breakpoint cluster region and fusion between the BCR and the c-ABL genes (BCR-ABL) oncogen product is a potential tumor-specific antigen. Previous studies have shown that T cells specific for the junctional region peptides of the BCR-ABL oncoprotein can be detected in healthy individuals as well as in patients with CML in chronic phase. We assessed whether BCR-ABL- specific T cells could be found in a patient achieving a complete cytogenetic remission after CD4+ donor lymphocyte infusion. METHODS: Using dendritic cells pulsed with BCR-ABL breakpoint peptides as antigen-presenting cells, we stimulated patient peripheral blood lymphocytes to isolate peptide-specific T cell clones present at the time of the cytogenetic response. T cell clones were isolated and the cellular specificity of these cells was examined. RESULTS: A CD3+ CD4+ T cell clone (1F7) that recognizes overlapping p210 junctional peptides presented by HLA-DR molecules was identified and expanded in vitro. Clone 1F7 failed to recognize autologous tumor cells as well as dendritic cells derived from patient CML cells. Clone 1F7 did not inhibit the growth and differentiation of CML precursor cells in a standard colony formation assay. Finally, using a clone-specific probe, 1F7 cells could not be detected in patient peripheral blood at the time of the donor lymphocyte infusion response. CONCLUSIONS: These results suggest that clone 1F7 was selected in vitro using highly potent peptide pulsed dendritic cells but was not representative of the anti-leukemia immune response in vivo. Based on these findings, CD4+ T cells with BCR-ABL specificity do not appear to be mediators of the anti-leukemia response in vivo after donor lymphocyte infusion.

Usefulness of pirenzepine, an M1 antimuscarinic agent, for effort myocardial ischemia.

This study evaluated the effect of pirenzepine, an M1 antimuscarinic agent, on exercise duration and ischemic threshold in patients with angiographically documented coronary artery disease and clear-cut ST depression (greater than 0.2 mV, 0.08 second after the J point) during ergometric stress testing. Twenty-five patients, mean age 56 +/- 8 years, underwent 3 randomized multistage bicycle exercise stress tests after intravenous administration of saline solution (2 ml), isosorbide dinitrate (1 mg) and pirenzepine (2 mg). Isosorbide dinitrate, an endothelium-independent coronary dilating agent, was used as a reference drug. Compared with saline, both pirenzepine and isosorbide dinitrate significantly improved time to ischemia (0.15 mV ST-segment depression) from 6.5 +/- 2 to 7.8 +/- 2 and 8.6 +/- 2 minutes and rate-pressure product at ischemia from 21,498 +/- 4,903 to 24,083 +/- 6,692 and 24,547 +/- 5,390 mm Hg.beats/min, respectively. Compared with saline, pirenzepine did not induce significant changes in blood pressure either at rest or during exercise, whereas it decreased resting heart rate from 71 +/- 9 to 60 +/- 11 beats/min (p less than 0.01) and induced a significant increment of heart rate during ischemia from 117 +/- 18 to 126 +/- 21 beats/min (p less than 0.05). Compared with saline, isosorbide dinitrate reduced systolic blood pressure at rest from 132 +/- 12 to 112 +/- 12 mm Hg, increased heart rate at rest from 71 +/- 10 to 84 +/- 16 beats/min and heart rate at ischemia from 117 +/- 18 to 132 +/- 16 beats/min.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term prognosis of transient acute myocardial ischemia at rest.

A medical approach to treatment was adopted in 652 patients with documented myocardial ischemia at rest during both the acute and follow-up phases. No patient underwent coronary revascularization during hospitalization and only 86 patients (13%) underwent coronary bypass surgery within 8 months from discharge. During hospitalization 13 patients died. In the remaining group (639 patients), the likelihood of death in the 10-year period after discharge was 28% for all patients and 20% for cardiac causes only. A series of factors studied during the acute stage were assessed in an effort to predict long-term outcome. The following noninvasive characteristics, listed in decreasing order of statistical significance, were found to be significant univariate predictors of survival: abnormal basal electrocardiogram, duration of coronary artery disease, previous myocardial infarction, pattern of ST-T changes during episodes of ischemia at rest, age and systemic hypertension. The average annual mortality rate for patients with T-wave changes, ST-segment elevation and ST-segment depression was 0.9, 1.8 and 3%, respectively. The Cox survival analysis identified abnormal basal electrocardiogram, duration of coronary artery disease and pattern of ST-T changes as significant, independent predictors of death. When invasive characteristics were entered in the model, number of greater than or equal to 50% narrowed coronary arteries, left ventricular ejection fraction, abnormal basal electrocardiogram and smoking habit were found to be independent and additive prognostic variables. Thus, long-term prognosis of patients with ischemia at rest is related to the severity of anatomic impairment, independent of the pattern of ST-T changes observed during the acute phase.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrocardiographic manifestations and in-hospital prognosis of transient acute myocardial ischemia at rest.

From January 1970 to June 1985, transient electrocardiographic changes at rest were documented in 652 patients admitted to our coronary care unit. Patients were stratified according to the type of electrocardiographic alteration at rest: 295 had ST-segment elevation (group 1), 106 T-wave changes (group 2) and 251 ST-segment depression (group 3). Patients in group 3, compared with groups 1 and 2, were more likely to have symptoms of coronary artery disease dating back many years (p less than 0.01 and p less than 0.01, respectively), a previous myocardial infarction (p less than 0.05 and difference not significant), a positive exercise test (p less than 0.01 and p less than 0.01), transient ST-T changes occurring in a higher number of electrocardiographic leads (p less than 0.01 and p less than 0.01), multivessel disease (p less than 0.001 and p less than 0.01) and poor ventricular function (p less than 0.01 and p less than 0.05). Despite these differences, the occurrence of acute myocardial infarction and cardiac death during hospitalization was much more frequent in group 1 compared with groups 2 (p less than 0.02) and 3 (p less than 0.05). However, death occurred in those patients who had poor ventricular function and severe atherosclerosis. A greater susceptibility of group 1 patients to severe vasoconstriction documented by the ergonovine test and by the occurrence of spontaneous spasm seems to account for different in-hospital outcome.

Early detachment of titanium particles from various different surfaces of endosseous dental implants.

Titanium (Ti) endosseous dental screws with different surfaces (smooth titanium--STi, titanium plasma-sprayed-TPS, alumina oxide sandblasted and acid-etched--Al-SLA, zirconium oxide sandblasted and acid etched--Zr-SLA) were implanted in femura and tibiae of sheep to investigate the biological evolution of the peri-implant tissues and detachment of Ti debris from the implant surfaces in early healing. Implants were not loaded. Sections of the screws and the peri-implant tissues obtained by sawing and grinding were analysed by light microscopy immediately after implantation (time 0) and after 14 days. All samples showed new bone trabeculae and vascularised medullary spaces in those areas where gaps between the implants and host bone were visible. In contrast, no osteogenesis was induced in the areas where the implants were initially positioned in close contact with the host bone. Chips of the pre-existing bone inducing new peri-implant neo-osteogenesis were surrounded by new bone trabeculae. The threads of some screws appeared to be deformed where the host bone showed fractures. Ti granules of 3-60 microm were detectable only in the peri-implant tissues of TPS implants both immediately after surgery and after 14 days, thus suggesting that this phenomenon may be related to the friction of the TPS coating during surgical insertion.

Changes in T cell receptor repertoire associated with graft-versus-tumor effect and graft-versus-host disease in patients with relapsed multiple myeloma after donor lymphocyte infusion.

Recent reports of clinical responses following donor lymphocyte infusions (DLI) in patients with relapsed multiple myeloma (MM) after allogeneic BMT have demonstrated the ability of allogeneic cells to mediate a graft-versus-myeloma (GVM) effect, but the mechanisms involved have not been determined. To identify changes in the T cell compartment associated with DLI, we performed a molecular analysis of the T cell receptor (TCR) repertoire in four patients with relapsed MM who received infusions of CD4+ lymphocytes from HLA-identical sibling donors. Three of the four patients demonstrated a clinical anti-myeloma response following DLI but also developed graft-versus-host disease (GVHD). The TCR repertoire was examined after PCR amplification of 24 Vbeta gene subfamilies. This method determines the relative utilization of each Vbeta gene subfamily and also allows the identification of clonal and oligoclonal T cell populations through analysis of CDR3 regions for each TCR Vbeta gene subfamily. Serial blood samples were obtained over at least a 1 year period before and after DLI and results compared to 10 normal donors. Serial analysis of CDR3 size profiles demonstrated the appearance of clonal T cell populations after DLI in each of the three responding patients. The appearance of some clones was noted within the first 3 months after DLI and coincided with decreasing levels of monoclonal paraprotein indicating an ongoing GVM response. Other T cell clones appeared at later time points and coincided with the development of GVHD. These findings demonstrate that T cell clones with different patterns of onset can be identified in the peripheral blood of MM patients following DLI. Further functional characterization of these distinct clonal expansions will be required to determine whether these T cell clones are mediators of either anti-myeloma or anti-host activity.

Autologous bone marrow transplantation in 44 patients with aggressive non-Hodgkin's lymphoma at University "La Sapienza" of Rome.

High dose therapy followed by infusion of autologous bone marrow has become a major treatment option for an increasing number of poor prognosis non-Hodgkin's lymphoma (NHL) patients. In our study we analyzed the outcome of autologous bone marrow transplantation (ABMT) in 44 high grade NHL patients transplanted at our institution between 1985 and 1992. Median age was 31 years (range 12-61); nineteen were in partial remission (PR) after first line chemotherapy and 25 in sensitive relapse (SR). Of the 25 patients transplanted in SR, 14 relapsed after a median time of 5.5 months (range 1-26), 8 are in complete remission after a median follow up of 41.5 months and three died from toxicity. Of the 19 patients grafted in PR, 11 are alive and progression free after a median follow up of 52 months, while 8 relapsed at a median time of 5 months. The overall progression free survival (PFS) projected at 6 years is 35% with a 47% PFS for patients transplanted in PR and 28% for patients in SR. In conclusion, high dose therapy and ABMT has achieved widespread use as salvage therapy for patients with relapsed/refractory high grade NHL. In particular, our experience confirms that myeloablative treatment is a safe and well tolerated procedure for patients in PR, that may be easily applied as early salvage therapy without major toxicities.

Accessory cells, cytokine loops and cell-to-cell interactions in chronic lymphocytic leukemia.

In addition to the extensive work that has been conducted in order to understand better the biological features of the leukemic population in B-cell chronic lymphocytic leukemia (CLL), over the years considerable interest has been directed towards other related studies that may have important implications for the accumulation of the leukemic clone and for the immunoparesis typical of this disease. In the present review article, we discuss some of these areas of investigation and, in particular, we focus on: (1) the multiple abnormalities recorded within the T and cytotoxic compartment of patients with CLL; (2) cytokine loops occurring in this disease, with particular emphasis on the cytokines that appear to play a more critical role; and (3) the cell-to-cell cross talk that may be actively operational in CLL. These findings will be discussed in relation with the possible implications that each of them have in the expansion and clinical behavior of a disease that is increasingly proving its heterogeneity.