Regulation of bim in glucocorticoid-mediated osteoblast apoptosis

Osteoblasts undergo apoptosis both in vitro and in vivo in response to high dose glucocorticoid (GC) treatment. However, the molecular mechanisms remain elusive, hindering the prevention and treatment of this side-effect. Apoptosis was induced by dexamethasone (Dex) in murine MBA-15.4 osteoblasts within 24-48 h of treatment. We found dose- and time-dependent upregulation of Bim protein, a pro-apoptotic Bcl-2 family member, with highest levels at 24-48 h for 1 microM Dex. This was also observed in primary human bone marrow stromal cells. Bim is subjected to stringent transcriptional and post-translational regulation in osteoblasts. Bim mRNA was upregulated in response to 1 microM Dex; both cycloheximide and the GC receptor antagonist, RU486, prevented Dex-induction of Bim protein, indicating transcriptional regulation involving the GC receptor. The proteasome inhibitor, MG132, potently increased Bim protein levels. Bim was also upregulated in osteoblasts undergoing apoptosis in response to serum deprivation and matrix detachment. Gene silencing experiments show that short interference RNA (siRNA) specific for Bim or the downstream effector Bax both reduced apoptosis induced by Dex in osteoblastic cells. These findings suggest that Bim is a novel regulator of osteoblast apoptosis and may be a therapeutic target.

[Abscess of the psoas muscle. Description of a series of 23 cases]

BACKGROUND

Abscess of the psoas muscle (PA) is an infrequent disease of difficult diagnosis. During the last decade, the number of cases has increased because of the raising use of radiology tecniques: ecography, computerized tomography and magnetic resonance nuclear.

METHODS

The presentation and management of psoas abscess was studied retrospectively in 23 patients from 1992 2000.

RESULTS

Sixteen of 23 abscesses were regarded as secundary: spondylodiscitis and pyelonefritis were most frequent pathologic processes. Homolateral pain in the flank area and hip were the usual manifestations. The duration of symptoms prior to the diagnosis was superior than 7 days. Staphylococcus aureus was the most common pathogen, followed by Escherichia coli and Mycobacterium tuberculosis. All abscesses were diagnosed by computerized tomography images. Seven patients underwent percutaneous drainage, while nine received surgical debridement. Four of the patients with psoas abscess died and only three relapsed.

CONCLUSIONS

Not specific symptoms and signs and subacute presentation difficult diagnosis of AP. High range antibiotics and drainage (percutaneous or surgical) should be considered as the election treatment.

Emerging treatments for epidemic (AIDS-related) Kaposi's sarcoma

Kaposi's sarcoma (KS) is an opportunistic tumor that develops with increased frequency (100,000-fold) after HIV infection. KS causes significant morbidity from mucocutaneous involvement and mortality from complications of visceral sites of disease such as the lungs, gastrointestinal tract, and the liver. Progressive unraveling of the KS pathogenesis has lead to the development of novel therapeutic approaches. Newest therapies are first evaluated in patients with limited tumor burden. These include: 1) inhibitors of angiogenesis such as vascular endothelial growth factor signaling inhibitor (SU 5416), and several other inhibitors of angiogenesis such as the dipeptide IM 862, TNP-470, Col-3, and thalidomide; 2) topical and systemic retinoids; 3) antiviral agents specific for Kaposi's sarcoma herpesvirus and human herpesvirus-8, or HIV; and 4) pregnancy-related factors. Patients with advanced disease such as widespread mucocutaneous disease, lymphedema, and visceral disease are treated most effectively with cytotoxic agents. The most active agents include liposomal anthracyclines, paclitaxel, vinca alkaloids, and bleomycin. The combination of liposomal anthracyclines and paclitaxel, with and without the most promising biologicals, should now be studied to further reduce the toxicity, and enhance the antitumor effects. Furthermore, identification of risk factors for KS should serve to explore prophylactic therapies.

Treatment of epidemic (AIDS-related) Kaposi's sarcoma

Kaposi's sarcoma (KS) is the most common tumor seen in patients with HIV-1 infection. KS causes significant morbidity and mortality through involvement of the skin and visceral organs. The optimal treatment for KS depends on the extent of the disease and immunologic status. However, with knowledge gained on the pathogenesis of disease, newer therapies and compounds are being developed. Early disease patients are best treated with either local therapy or agents that have low toxicity and can be delivered long term. Advanced disease, such as in patients with widespread mucocutaneous disease, lymphedema, and visceral disease, are treated most effectively with cytotoxic agents such as liposomal anthracyclines, vinca alkaloids, or paclitaxel. Future treatment developments are focusing on the role of effective anti-HIV therapy and anti-human herpesvirus (HHV)-8 therapy in an effort to interfere with key steps in the etiology of KS to control the disease. Secondly, agents that focus on the interruption of autocrine and paracrine growth factors such as vascular endothelial cell growth factor and basic fibroblast growth factor, interleukin-6, and interleukin-8 are of therapeutic interest. Some of these compounds currently under evaluation include antiangiogenesis inhibitors and retinoids.

Mitoguazone therapy in patients with refractory or relapsed AIDS-related lymphoma: results from a multicenter phase II trial

PURPOSE

Patients with AIDS-related lymphoma usually have extensive lymphomatous disease, with relatively frequent involvement of the CNS. Approximately half may achieve complete remission after chemotherapy. Mitoguazone, an inhibitor of polyamine biosynthesis, has demonstrated efficacy in patients with de novo recurrent lymphoma. The drug is relatively nonmyelotoxic and may cross the blood-brain barrier. The current study was designed to assess the safety and potential efficacy of mitoguazone in patients with relapsed or refractory AIDS-lymphoma.

PATIENTS AND METHODS

Thirty-five patients were accrued, all of whom had failed one (51%) or multiple (two to six) prior regimens. Mitoguazone (600 mg/m2) was given intravenously on days 1 and 8, and then every 2 weeks, until best response, progression, or toxicity.

RESULTS

The median age was 39 years. High-grade lymphoma was diagnosed in 29 patients (83%). Extranodal disease was present in 30 patients (86%), with multiple extranodal sites (two to seven) in 18 (51%). The median CD4 cell count at study entry was 66/dL (range, zero to 549). Twenty-six patients were assessable for response. The objective response rate was 23% (95% confidence interval [CI], 6.9 to 39.3), with complete remission in three patients (11.5%), and partial remission (PR) in three patients (11.5%). Six patients experienced stable disease. Median survival from study entry was 2.6 months for the group as a whole; 21.5 months (range, 3.8 to 29.1) in complete responders, 5.6 months (range, 3.8 to 34.8) in partial responders. The most common toxicities occurred solely during drug infusion and included vasodilation (63%), paresthesia (86%), and somnolence (17%). Fourteen patients (40%) experienced nausea and 16 (46%) vomiting (grade 3 in one). Ten patients (29%) developed stomatitis, including grade 3 in two and grade 4 in one. Seven patients (20%) developed neutropenia, with grade 4 in one. Thrombocytopenia occurred in nine patients (26%). While on study, three patients developed sepsis, four had pneumonia, and two developed opportunistic infections.

CONCLUSION

Mitoguazone is an effective agent in patients with multiply relapsed or refractory AIDS-related lymphoma, with acceptable toxicity. Further study in patients with newly diagnosed disease is warranted.

Low dose methotrexate, bleomycin, doxorubicin, cyclophosphamide, vincristine, and dexamethasone with zalcitabine in patients with acquired immunodeficiency syndrome-related lymphoma. Effect on human immunodeficiency virus and serum interleukin-6 levels over time

BACKGROUND

Use of multiagent chemotherapy has been associated with complete remission (CR) in approximately 50% of patients with newly diagnosed acquired immunodeficiency syndrome (AIDS)-lymphoma, although additional AIDS-related complications may occur. Both chemotherapy and antiretroviral therapy were employed in an attempt to ascertain if the combination was safe, and associated with changes in human immunodeficiency virus (HIV) p24 antigen levels during the course of treatment.

METHODS

Low dose methotrexate, bleomycin, doxorubicin, cyclophosphamide, vincristine, and dexamethasone(M-BACOD) chemotherapy and zalcitabine (ddC) were employed in 28 patients. Since both vincristine and zalcitabine may cause peripheral neuropathy, a Phase I/II study design was employed. Serum was analyzed for immune complex dissociated (ICD) HIV p24 antigen and interleukin (IL)-6 levels during therapy.

RESULTS

CR was achieved in 14 of 25 patients (56%), with partial response (PR) in 5 (20%). CRs were equivalent in patients with good or poor prognostic indicators, including a history of AIDS prior to lymphoma (CR = 60%); and/or CD4 lymphocytes < 200/mm3 (CR = 53%). Five patients with a CR subsequently relapsed (36%); median survival of CR patients was 29.2 months (4.1-61+), whereas that of all of the treated patients was 8.1 months. No significant peripheral neuropathy or other toxicity was observed. Serum ICD p24 antigen levels either fell (7/14) or remained consistently negative (2/14) in 9 of 14 patients (64%), whereas 36% experienced an increase. Elevated serum IL-6 levels at diagnosis were associated with systemic "B" symptoms (P = 0.023), whereas changes in IL-6 correlated with response to therapy over time (P = 0.006).

CONCLUSIONS

Combination antineoplastic and zalcitabine antiretroviral therapy may be safely administered to patients with AIDS-related lymphoma, resulting in CR in 56%, lack of significant neurotoxicity, and favorable effect on HIV p24 antigen in 50%. Elevation of serum IL-6 is associated with systemic "B" symptoms, whereas changes in serum IL-6 may correlate with response.

Thrombotic thrombocytopenic purpura in patients with human immunodeficiency virus infection: a report of three cases and review of the literature

Three cases of thrombotic thrombocytopenic purpura (TTP) and coexistent human immunodeficiency virus (HIV) infection are presented with a review of 15 cases reported in the literature. Of the 18 total patients, one-half presented with no symptoms of HIV infection while nine patients presented with symptomatic HIV disease before or simultaneous to the diagnosis. The presenting symptoms were similar to those with classic TTP and included fever in 75% and 40% with neurologic symptoms. Laboratory parameters reflected the microangiopathic hemolytic anemia typically seen in patients with TTP. The median hematocrit was 19.4%, while the median platelet count was 16,000/mm3. As with classic TTP, patients with HIV-related TTP only had mild renal dysfunction (median creatinine of 1.2 mg/dl, range 0.8-4.8 mg/dl). Plasma exchange produced clinical remission in a majority of the patients. Importantly, approximately one-third of the patients died prior to the initiation of therapy. We conclude that TTP is a rare but treatable condition in patients with HIV infection. A TTP diagnosis should be considered in patients with HIV infection who present with severe anemia and thrombocytopenia. Plasma exchange should be considered as initial therapy. The role of both antiplatelet therapy and aspirin is unknown.

Intravenous immune globulin use in patients with human immunodeficiency virus-related thrombocytopenia who require dental extraction

Five patients with human immunodeficiency virus (HIV)-related immune thrombocytopenia who were undergoing dental extraction were treated with intravenous immune globulin (IVIG). All patients received IVIG, 1 gram per kg, the day before the dental extraction and again the day of the dental extraction. Four patients had a previous history of minor clinical bleeding. The median baseline platelet count before extraction was 20 X 10(9) per liter (range 13 to 44). The median peak platelet count was 100 X 10(9) per liter (range 56 to 528) following infusion. This peak response was achieved by day 2 in 3 patients and by days 5 and 7 in 1 patient each. No patients had complications or toxicity from the infusions or perioperative bleeding. No patients required blood product transfusions for the surgical procedure. In conclusion, IVIG infusion should be considered in patients with HIV-related immune thrombocytopenia requiring surgical procedures when a prompt rise in platelet count is desired.

The long-term use of zidovudine in patients with severe immune-mediated thrombocytopenia secondary to infection with HIV

Various treatments for HIV-related thrombocytopenia have been reported. Since etiologies of the thrombocytopenia may differ with regard to risk group treatment outcomes may also vary. We have recently studied the long-term use of zidovudine in individuals with sexually transmitted HIV infection and severe thrombocytopenia. Twenty-five men, median age 34 years (range, 23-51 years), were treated with zidovudine (1000 mg/day) for a median duration of 12 months (range, 2.5- less than 26 months). Nineteen patients (76%) had had episodes of symptomatic bleeding secondary to thrombocytopenia prior to study entry. All patients bleeding symptoms resolved with therapy. Six (24%) achieved a complete response, with normalization of platelet counts, while 11 patients (44%) achieved a partial response, giving an overall response rate of 68%. The median time to partial or complete normalization of platelet counts was 12 weeks (range, 4-62 weeks). Toxicities were minimal during the study period. Only one patient developed an AIDS-defining diagnosis while on therapy. We conclude that patients with sexually transmitted HIV infection and immune thrombocytopenia may need a prolonged period of therapy with zidovudine to achieve a platelet response. Other treatment modalities may be required for the 30% of patients who do not respond to zidovudine.

Advanced acquired immune deficiency syndrome-related Kaposi's sarcoma. Results of pilot studies using combination chemotherapy

Pilot studies were conducted to evaluate the toxicity and efficacy of two relatively marrow-sparing chemotherapy regimens in the treatment of advanced or progressive epidemic Kaposi's sarcoma. Chemotherapy regimens consisted of bleomycin (10 mg/m2), vincristine (1.4 mg/m2, 2 mg maximum) and Adriamycin (doxorubicin) at either 10 mg/m2 (Group I) or 20 mg/m2 (Group II). The therapy was given intravenously, every 2 weeks, until intolerable toxicity or maximum antitumor response. Thirty-three patients were treated. Although the patient populations were similar regarding pretreatment prognostic factors, the patients were not assigned randomly to these two treatment regimens. Major responses (complete or partial remission) were attained in 79% of the cases. The treatment-related toxicities consisted of mild to moderate nausea, hair loss, and peripheral sensory neuropathy. Bone marrow suppression consisted primarily of neutropenia (less than 1000/mm3) which occurred in a third of the patients. Variables significantly associated with shorter survival included hemoglobin (less than 10 g/dl), low Karnofsky performance status (less than 70%), and weight loss. Opportunistic infections occurred in the majority of cases during administration of chemotherapy, and were most likely related to severe cell-mediated immune dysfunction and low CD4-positive lymphocyte counts.