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Biomedical subjects

D Samson

Publications and source records attributed to D Samson.

At least 19 recordsLinked to original sources
PubMed1997

A human homologue of the Drosophila eyes absent gene underlies branchio-oto-renal (BOR) syndrome and identifies a novel gene family.

A candidate gene for Branchio-Oto-Renal (BOR) syndrome was identified at chromosome 8q13.3 by positional cloning and shown to underlie the disease. This gene is a human homologue of the Drosophila eyes absent gene (eya), and was therefore called EYA1. A highly conserved 271-amino acid C-terminal region was also found in the products of two other human genes (EYA2 and EYA3), demonstrating the existence of a novel gene family. The expression pattern of the murine EYA1 orthologue, Eya1, suggests a role in the development of all components of the inner ear, from the emergence of the otic placode. In the developing kidney, the expression pattern is indicative of a role for Eya1 in the metanephric cells surrounding the 'just-divided' ureteric branches.

Adult↗
PubMed1997

Does electrothrombosis occur immediately after embolization of an aneurysm with Guglielmi detachable coils?

Current options for treating cerebral aneurysms include surgical clipping and placement of Guglielmi detachable coils (GDCs). The latter system is reported to induce acute aneurysmal occlusion by a mechanism of electrothrombosis. We report our observations in the case of a ruptured aneurysm treated with GDCs and then surgically exposed 2 hours later. The lack of thrombus within the aneurysm and around the coils led us to question the mechanism of action of GDCs.

Aneurysm, Ruptured↗
PubMed1996

Allogeneic bone marrow transplantation versus autologous stem cell transplantation in multiple myeloma: a retrospective case-matched study from the European Group for Blood and Marrow Transplantation.

A retrospective case-matched analysis was performed comparing 189 myeloma patients treated with allogeneic bone marrow transplantation (allo-BMT) with an equal number of patients who received autologous stem cell transplantation (ASCT). Matching was performed with respect to gender and number of treatment lines before transplantation. The groups were comparable with the exception of median age (43 years for allo-BMT v 49 years for ASCT, P = .0001) and median posttransplant follow-up (46 months for allo-BMT v 30 months for ASCT, P = .0003). The overall survival was significantly better for ASCT than for allo-BMT, with a median survival of 34 months and 18 months, respectively (P = .001). However, this survival advantage was only observed in men, but not in women. The statistically significant survival advantage for ASCT was seen in most subgroups, ie, chemotherapy-responsive patients, patients who had received two or more treatment lines before transplantation, patients in partial remission, patients with an IgG-subtype, patients older than 46 years of age, patients with stage II disease, and patients with a low or high serum-beta-2-microglobulin at diagnosis. The main reason for the poorer survival in allo-BMT patients was higher transplant-related mortality (41% v 13% for ASCT, P = .0001), which was not compensated for by a lower rate of relapse and progression. However, in patients alive at 1 year posttransplant, there was a trend for better long-term survival (P = .09) and significantly better progression-free survival (P = .02) for allo-BMT as compared with ASCT. We conclude that the median survival is superior for ASCT. However, allo-BMT has a lower relapse rate, which results in a similar long-term outcome for both approaches, but a longer follow-up is needed to assess the final outcome.

Acute Disease↗
PubMed1996

Biochemical bone markers in patients with multiple myeloma.

Enhanced bone resorption is a characteristic finding in multiple myeloma (MM). The aim of this study was to assess the newer biochemical bone markers in patients with myeloma. We studied 17 MM patients--10 males (3 untreated, 5 in remission, 2 responding), 7 females (3 in remission, 4 responding) and 15 normal controls. Serum bone specific alkaline phosphatase (BSALP), osteocalcin (OC) and procollagen type 1 C-terminal peptide (PICP) were determined as markers of bone formation, while serum tartrate resistant acid phosphatase (TRAP), urinary deoxypyridinoline (Dpyr) and calcium (Ca) were determined as markers of bone resorption and the ratio of the levels of bone formation/resorption were determined. All markers were measured by enzyme immunoassays (Metra Biosystems), except for TRAP by an in-house enzymatic assay and Ca by the cresolphthalein method. The Dpyr and Ca were expressed as a ratio to urinary creatinine (Cr) excretion. There were significantly higher (i) (Dpyr/Cr)/PICP ratio in male MM patients than in controls (P < 0.05); (ii) (a) urinary Dpyr excretion (P < 0.001), (b) (Dpyr/Cr)/BSALP ratio (P < 0.0001) and (c) (Dpyr/Cr)/PICP (P < 0.0001) in the untreated male MM subgroup than controls; (iii) (Dpyr/Cr)/BSALP ratio (P < 0.05) in the untreated than in the responding male MM subgroup, (iv) (Dpyr/Cr)/PICP ratio (P < 0.05) in untreated male patients than in those in the remission subgroup. In conclusion, (a) Dpyr is a sensitive marker in assessment of bone resorption in MM patients; (b) (Dpyr/Cr)/BSALP or (Dpyr/Cr)/PICP ratio is even more sensitive in distinguishing the untreated from the other MM subgroups and controls. Therefore, the use of a combination of these markers may have a potential role in the management of patients with MM.

Acid Phosphatase↗
PubMed1996

A comprehensive genetic map of the human genome based on 5,264 microsatellites.

The great increase in successful linkage studies in a number of higher eukaryotes during recent years has essentially resulted from major improvements in reference genetic linkage maps, which at present consist of short tandem repeat polymorphisms of simple sequences or microsatellites. We report here the last version of the Généthon human linkage map. This map consists of 5,264 short tandem (AC/TG)n repeat polymorphisms with a mean heterozygosity of 70%. The map spans a sex-averaged genetic distance of 3,699 cM and comprises 2,335 positions, of which 2,032 could be ordered with an odds ratio of at least 1,000:1 against alternative orders. The average interval size is 1.6 cM; 59% of the map is covered by intervals of 2 cM at most and 1% remains in intervals above 10 cM.

Algorithms↗
PubMed1996

Intracavernous carotid artery aneurysms: the possible importance of angiographic dural waisting. A case report.

BACKGROUND: Cavernous carotid aneurysms are generally benign entities. Certain indications exist for their treatment, however, including transient ischemic events, subarachnoid hemorrhage or risk of subarachnoid hemorrhage, epistaxis or its risk, ophthalmoplegia, pain, and progressive visual loss. We feel certain angiographic features may indicate a greater likelihood that cavernous carotid aneurysms extend into the subarachnoid space, thus making their rupture a life-threatening event. METHODS: A case report of an intracavernous carotid aneurysm, which at surgery extended into the subarachnoid space, is described. RESULTS: In this particular case, deformation of the aneurysm (waisting) as seen at angiography was in retrospect an indication that the cavernous carotid aneurysm extended into the subarachnoid space, either through the dural ring or through the eroded dural roof of the cavernous sinus. This finding was verified at surgery when the lesion was explored and trapped. CONCLUSION: Angiographic waisting of a cavernous carotid aneurysm may indicate that the aneurysm extends into the subarachnoid space. Such extension means that rupture would be a life-threatening event. While deformation of the aneurysm may be secondary to compression against the optic nerve or anterior clinoid process with an intact layer of dura overlying the aneurysm, the neurosurgeon confronted with such findings should analyze such lesions carefully and consider surgical exploration.

Aged↗
PubMed1996

A randomized study of VAD therapy with either concurrent or maintenance interferon in patients with newly diagnosed multiple myeloma.

This randomized study was designed to determine whether response to VAD chemotherapy could be prolonged by using rh alpha-2b-interferon (IFN) at a dose of 3 mU three times per week, either concurrently with VAD (VIC) or as maintenance after completion of VAD (VIF). Maintenance IFN was given for 9 months in order for the duration of IFN therapy to be similar in both groups. 72 patients were randomized between December 1988 and August 1993. The majority of patients had poor prognostic features. The objective response rate was similar in each arm, 78% in VIF and 77% in VIC. Of the 56 responders, 33 have relapsed, three died in remission, and 18 proceeded to high-dose therapy, withdrew for other reasons or were lost to follow-up and were censored from analysis at the relevant time point. Only two patients remain in remission (both in partial remission). Median PFS was 15 months for both VIF and VIC, compared with 16.5 months for a historic control group treated with VAD alone (n.s.). The estimated median survival in VIF was 43 months and in VIC 22 months, compared with 45 months in the historic controls (n.s.). These findings indicate that neither maintenance nor concurrent IFN prolongs response to VAD.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Feasibility and toxicity of interferon maintenance therapy after allogeneic BMT for multiple myeloma: a pilot study of the EBMT.

A pilot study was undertaken in order to determine the feasibility and toxicity of rh-alpha-2b-interferon as maintenance therapy after allogeneic BMT for multiple myeloma. The study incorporated planned dose escalation of interferon in successive patient cohorts from an initial dose of 1 MU three times weekly to a target dose of 3 MU three times weekly. No clinical complications were observed in five patients receiving a dose of 1 Mu three times weekly. At a dose of 2 MU three times weekly, one of seven patients developed acute GVHD, which was fatal. At a dose of 3 MU three times weekly, four of five patients developed acute or chronic GVHD, and the study was therefore terminated at this point. We conclude that the use of interferon in myeloma patients early after allogeneic BMT is associated with a significant risk of GVHD, which is dose-related, and that the maximum tolerated dose in the early post-transplant period is 1-2 MU three times weekly.

Adult↗
PubMed1995

Treatment of dural sinus thrombosis using selective catheterization and urokinase.

Thrombosis of the cerebral dural venous sinuses, cortical draining veins, and deep cerebral veins is a rare clinical finding. Because of its low incidence and multiple etiologies, the optimum therapy for this condition will only be elucidated by a multicenter, randomized prospective study. At our institution, we favor early and aggressive management of cerebral venous sinus thrombosis with transfemoral, venous intradural infusions of the fibrinolytic agent urokinase. To date, treatment of only 13 patients using this technique has been reported in the English literature. This report adds 12 more such treated patients. Despite the presence of preinfusion infarcts in 5 patients, four of which were hemorrhagic, we incurred no major therapeutic morbidity. Functional sinus patency was achieved in 11 of 12 patients, with our only true failure occurring in an individual with symptoms of at least 2 months' duration. Good to excellent clinical outcome was achieved in 10 of 11 patients (one newborn had inadequate follow-up).

Adult↗
PubMed1995

Autologous stem cell transplantation in multiple myeloma: results of the European Group for Bone Marrow Transplantation.

Autologous hematopoietic stem cell transplantation was used for treatment of 384 patients with multiple myeloma in 37 centers during the years 1986-1994. An analysis of prognostic factors was performed in 207 of these patients. One hundred forty one were males and 66 females, and median age was 49 years (range, 24-68). Actuarial survival at 78 months is 45%. Factors associated with a good prognosis were: response on chemotherapy immediately pretransplant, administration of only one treatment regimen, a low serum-beta 2-Microglobulin value at diagnosis and the use of a conditioning regimen including melphalan. In a multivariate analysis, response status pretransplant, age < 45 years, melphalan conditioning and non-TBI conditioning were independently predictive for longer survival, while transplantation after only one line of primary treatment and isotype other than light-chain were of borderline significance. Post-transplant alpha-interferon treatment was associated with improved survival in responsive patients. Eighteen patients treated in one center (Huddinge) passed a double autograft program, and 14 are in continuous complete remission ([CR]; n = 10) or good partial remission (n = 4) at a median time of 17 months after the first transplant (range, 2-38). In five CR patients, polymerase chain reaction (PCR)-analysis of the clone-specific immunoglobulin-rearrangement was performed, and four are PCR-negative up to 33+ months after the first transplantation. We conclude that autografting in myeloma is most effective when applied early in the course of disease in younger, chemotherapy-reponsive patients. Alpha-interferon maintaince treatment seems to be beneficial with respect to improved survival.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Changes in coagulation and fibrinolysis in patients with sickle cell disease compared with healthy black controls.

Seventeen parameters of coagulation and fibrinolysis were measured in 33 patients with sickle cell disease; 30 were tested in steady state (SS) and 19 in crisis (Cr). There were 16 patients in both groups. The same parameters were measured in 16 controls of similar ethnic origin (Black controls; BC) and 20 Caucasian controls (CC), all with HbA only. Highly significant differences (P < 0.001) between Black and Caucasian control groups were noted for: fibrinogen, fibrinopeptide-A (FPA), beta-thromboglobulin (beta TG) and D-dimer. Significant differences (P < 0.03) in plasminogen activator inhibitor (PAI) and functional antithrombin III levels were also noted. Results of the sickle cell patients were therefore compared with those of the Black controls. Sickle cell patients in SS had raised v Wf compared with BC, which increased further during Cr (P = 0.001), but showed no significant increase in fibrinogen. Functional protein C was reduced in SS (P = 0.004) but with no further fall in Cr, while free protein S was normal in SS but reduced in Cr (P = 0.02). Total protein S and ATIII were normal in SS and Cr. FPA and beta TG were not significantly raised in SS or Cr compared with BC. There were, however, highly significant increases in D-dimer and thrombin-antithrombin complexes (TAT) in both SS and Cr compared with BC (P < 0.001 for SS and Cr vs BC). Thus significant activation of coagulation with consequent increase in fibrinolysis occurs during both the sickle cell crisis and in the steady state.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Double high-dose chemoradiotherapy with autologous stem cell transplantation can induce molecular remissions in multiple myeloma.

Fifteen patients with stage II-III multiple myeloma were intended to undergo two sequential cycles of myeloablative chemoradiotherapy with autologous bone marrow or blood stem cell transplantation after response to primary induction chemotherapy. BM grafts were used in 13 of the 15 first transplants whereas PBSC were used for the two remaining first transplants and all second transplants. The preparative regimen was melphalan 200 mg/m2 for the first transplant and melphalan 140 mg/m2 plus total body irradiation (TBI) 10 Gy for the second. Before the first transplant, 12 patients were in PR and three in CR whereas seven were in CR and seven in PR after the first transplantation. Four patients received only one cycle of myeloablative therapy because of incomplete hematopoietic reconstitution after transplantation (three patients) and early death (one patient). Eleven patients proceeded to the second transplant, and six patients were then in CR and five in PR. After the second transplant a further two patients entered CR whereas three remained in PR. Of all 15 patients, 11 remain in continuous complete (eight patients) or partial (3 patients) remission at a mean time of 20 months after the first transplant. Five patients in CR were examined by PCR analysis of the clone-specific immunoglobulin gene rearrangement for detection of minimal residual disease and four of these are PCR-negative up to 33 months after the first transplant. One transplant-related death occurred, and one patient died from progressive disease. This superintensive treatment regimen for younger patients with multiple myeloma has acceptable toxicity, and can induce and sustain long-term complete remissions.

Adult↗
PubMed1994

Plasma thrombomodulin in orthotopic liver transplantation.

Plasma thrombomodulin (TM), a specific marker of vascular endothelial injury was measured pre-, per-, and postoperatively in 16 consecutive patients undergoing orthotopic liver transplantation (OLT). The TM level, which was already elevated preoperatively, remained unchanged during OLT, except for an acute and transitory spike at the time of graft reperfusion. This TM peak is probably attributable to an acute release from the patient's endothelium because the TM level in the last saline rinse of the graft before implantation was low. This TM spike was not correlated with the progressive tissue-type plasminogen activator (t-PA) increase, plasminogen activator inhibitor 1 (PAI-1), or von Willebrand factor (vWF) values. The absence of accumulation of TM in plasma, unlike that of t-PA, suggests that the liver does not play a major role in TM clearance in humans. At the end of surgery, individual TM values returned to preoperative levels and remained unchanged during the 7 days following surgery. This observation suggests that the high (or very high) TM levels measured in these patients might be due to an indirect rather than a direct effect of liver dysfunction on the vascular endothelium which remained damaged during the postoperative period. The possibility that TM might be a predictive marker for thrombotic OLT complications remains to be investigated in a postoperative follow-up study.

Adolescent↗