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Biomedical subjects

T Petit

Publications and source records attributed to T Petit.

At least 91 records · Page 5Linked to original sources
PubMed1996

Complete remission seven years after treatment for metastatic malignant melanoma.

BACKGROUND: In this study, the authors identified seven-year survivors after completion of the French multicenter Phase II trial of fotemustine for the treatment of metastatic malignant melanoma. METHODS: One hundred sixty-nine patients with metastatic malignant melanoma were included in this Phase II study. One hundred fifty-three patient records were evaluable with an overall response rate of 24.2%. RESULTS: Five of these patients are alive and in complete remission. One patient had a complete response after fotemustine administration and then relapsed. One patient had a partial response. Three patients had stable disease. These five patients underwent surgery for relapse or residual disease and subsequently achieved durable complete remission. CONCLUSIONS: Long term survival may be the outcome after surgical resection of residual metastatic melanoma after chemotherapy.

Antineoplastic Agents↗
PubMed1996

Schizosaccharomyces pombe possesses an unusual and a conventional hexokinase: biochemical and molecular characterization of both hexokinases.

Two hexokinases were characterized in Schizosaccharomyces pombe: hexokinase 1, with a low phosphorylation coefficient on glucose (Km 8.5 mM) and hexokinase 2, a kinetically conventional hexokinase. Genes hxk1+ and hxk2+ encoding these enzymes were cloned and sequenced. Disruption of hxk1+ had no effect on growth but disruption of hxk2+ doubled the generation time in glucose. Spores carrying the double disruption hxk1+ hxk2+ did not grow on glucose or fructose after one week. Expression of hxk1+ increased strongly during growth in fructose or glycerol. Expression of hxk2+ was highest during growth in glycerol. A NADP-dependent glucose dehydrogenase was detected, but not a glucokinase.

Amino Acid Sequence↗
PubMed1996

Volvulus of the sigmoid colon as a complication of segmental dilatation of the colon. Report of 2 cases.

Sigmoid volvulus is an unusual cause of intestinal obstruction in children. We report two cases of sigmoid volvulus as a complication of segmental dilatation of the colon occurring in two girls (5 years old and 9 years old) previously treated for chronic constipation. In both cases the constipation had been recognised since the neonatal period mimicking a Hirschsprung's disease, a diagnosis which has been excluded after rectal biopsy. The delayed diagnosis of segmental dilatation of the sigmoid colon followed the volvulus. Segmental colonic resection resulted in both cases in the cure of the constipation.

Child↗
PubMed1996

[Value of endoscopic incisions in the treatment of ureteroceles in children].

Endoscopic incision is a simple method to provide decompression of the urinary tract above ureteroceles. This technique has been used in most cases of ureterocele seen since 1987. In 6 cases of ureterocele in a single system good results were achieved in all cases. In 13 cases of ureterocele in a duplex system, incision was the only procedure in 5 patients. Seven patients required further surgery : upper pole partial nephrectomy when dilatation persisted, ureteral reimplantation and ureterocele excision in cases of upper pole reflux, secondary to the endoscopic incision, or in cases of persistent reflux in the lower pole ureter. Endoscopic incision is a safe treatment in cases of intravesical ureterocele (single system or duplex system) but in the cases of ectopic ureteroceles, it generally provides only temporary benefit. In these cases, it facilitates delayed lower urinary tract surgery.

Age Factors↗
PubMed1996

[Carboplatin and cyclophosphamide in stage Ic-IV ovarian carcinoma: retrospective study of 101 cases].

We report our experience of CBDCA-CPM combination chemotherapy as first line therapy in 101 ovarian cancers. The therapeutic scheme was: initial cytoreductive surgery followed by six chemotherapy cycles (CBDCA 400 mg/m2/d IV dl, CPM 600 mg/m2/d IV dl, dl = d21) and second-look laparotomy. The initial stages were four Ic, three IIa, four IIb, four IIc, 15 IIIa, 28 IIIb, 23 IIIc and 20 IV. After initial surgery, there were 39 macroscopic residual diseases superior to 2 cm, 26 macroscopic residual diseases inferior or equal to 2 cm, four microscopic diseases and no residual disease in 30 cases (unknown in two cases). The overall response rate to chemotherapy was 83% with 56% histologic complete response rate. The main toxicity was haematological with 60% of leucopenia grade III-IV, 52% of thrombopenia grade III-IV. Age at diagnosis, residual disease after first look surgery and length of CA 125 normalization were significant prognostic factors for survival in this series.

Adolescent↗
PubMed1996

[Contribution of cancer registries to the evaluation of cancer treatment: on the example of rectal cancer].

Improvement of health care policy requires an assessment of health care practices. In France, morbidity registries might be the best tool for such an assessment. This study shows how the treatment of rectal cancer can be assessed by French cancer registries. Two studies were conducted: a cross-sectional study on data from 7 cancer registries in 1990 and a longitudinal study on data from 2 digestive cancer registries (departments of Calvados and Côte d'Or) between 1978 and 1990. Finally, we conducted a regional audit concerning quality control in rectal resection for cancer in Lower Normandy between 1988 and 1993. In 1990 the mean resection rate was 77.8%. The sphincter preservation rate was also significantly increased to 53.9% in 1990. The use of adjuvant radiotherapy significantly increased between 1978 and 1990, more rapidly in university centres. In more recent years, the use of radiotherapy concerned 50% of resected rectal cancers with no differences between the various types of health care centres. However, in 1990, major geographical variations were observed for the use of adjuvant radiotherapy. Similar geographical variations were observed for the use of chemotherapy which did not increase with time. Rectal cancers were not diagnosed earlier from 1978 to 1990 in the two departments of Calvados and Côte d'Or. The use of reproducible quality criteria (length of distal excision, number of nodes examined and histological status of lateral margins) showed a global deficiency and marked variations between the various types of health care centres and levels of surgical training. The french network of French cancer registries (FRANCIM) provides accurate and reliable knowledge on medical practices, geographical variations, trends and quality control. The potential of cancer registries has not been clearly determined, although such information is required to plan health care policy.

Cross-Sectional Studies↗
PubMed1995

Fotemustine, dacarbazine, vindesine combination chemotherapy in advanced malignant melanoma: a phase II study of 43 patients.

Fotemustine and dacarbazine constitute the most active single chemotherapeutic agents in the treatment of melanoma. In this phase II study we evaluated the activity and toxicity of a combination of fotemustine, dacarbazine and vindesine as a means of increasing response rate and survival time. Between September 1989 and November 1993, 43 patients with advanced melanoma were treated with a combination of 100 mg/m2 fotemustine on days 1 and 8, 250 mg/m2 dacarbazine on days 15 and 16 and 2 mg/m2 vindesine on days 15 and 16 as induction treatment. After a 5-week rest period, the patients exhibiting a response or stable disease received the same drugs administered once every 28 days as maintenance therapy until either progression or toxicity was observed. Among 41 evaluable patients, there were six complete responses and eight partial responses. The overall response rate was 32% (95% confidence interval: 18-46%), with 8 months median duration of response. Median survival time was 10 months. This regimen was well tolerated. From this large phase II study, we conclude that such a combination is active against advanced malignant melanoma and seems to be more effective than fotemustine or dacarbazine used alone, especially on visceral metastatic sites.

Adult↗
PubMed1995

A highly sensitive polymerase chain reaction method reveals the ubiquitous presence of maternal cells in human umbilical cord blood.

Umbilical cord blood is considered an alternate source of hematopoietic stem cells in bone marrow transplantation. However, its use might be hampered by contamination of neonatal blood with maternal cells, which could contribute unacceptably to graft-vs.-host disease (GVHD) after transplant. In a previous study (Socié et al., Blood 83:340, 1994), we used polymerase chain reaction (PCR) amplification of minisatellite sequences (sensitivity 1-0.1%) to address the question of this contamination. In a single case among 47 analyzed, we were able to detect a maternal-specific allele in the cord blood sample. We have now studied the same cord samples using a highly sensitive, allele-specific PCR amplification method. A maternal allele could be discriminated from neonate alleles in 10 cases and maternal cells were detected in all 10 cord blood samples. These cells amounted to 10(-4) to 10(-5) of cord blood nucleated cells. In three cases, cord blood separated cell subpopulations could be analyzed and were found to contain maternal cells at about the same level. The presence of maternal cells at such a low level in cord blood samples probably would have no effect on GVHD in a clinical setting of transplantation but raises interesting questions in terms of materno-fetal immune tolerance and transmission of viruses (in particular human immunodeficiency virus) from infected mother to child.

Alleles↗
PubMed1994

Accumulation of trehalose in Saccharomyces cerevisiae growing on maltose is dependent on the TPS1 gene encoding the UDPglucose-linked trehalose synthase.

When yeast strains were cultivated on maltose, the synthesis of trehalose already started in the exponential phase of growth, well before exhaustion of the sugar from the medium. This active pattern of trehalose accumulation was also observed in a maltose constitutive mutant strain growing on glucose. However, this accumulation was completely prevented by deletion of the TPS1 gene coding for the catalytic subunit of the UDPglucose-linked trehalose-6-phosphate synthase, indicating that no alternative pathway for trehalose synthesis exists in yeast. The active pattern of trehalose accumulation seems to be consistent with the finding that trehalose-6-phosphate synthase is more active in strains growing on maltose than on glucose.

Gene Deletion↗
PubMed1994

Highly sensitive polymerase chain reaction methods show the frequent survival of residual recipient multipotent progenitors after non-T-cell-depleted bone marrow transplantation.

Twenty-four male patients grafted for various pathologies with the marrow of a female donor and presenting a complete donor-type hematopoiesis when analyzed by polymerase chain reaction (PCR) amplification of minisatellite sequences 33.6.3 and MS51 (0.1% to 1% sensitivity) were studied by the highly sensitive technique of PCR amplification of the Y-chromosome-specific DYZ1 sequence (0.01% sensitivity). Residual recipient male cells were detected in all peripheral blood samples collected within 1 year posttransplantation. These residual cells were present in both the lymphocyte and polymorphonuclear cell fractions when such a separation was performed by Ficoll gradient centrifugation and, for samples of 13 of 15 patients, at comparable levels in both fractions. In 3 samples collected from 3 patients 4 months or more posttransplantation, residual recipient cells were detected in the polymorphonuclear cell fraction but were present at a lower level or were undetectable in the lymphocyte fraction. These cells are of hematopoietic origin because they were detected at equivalent levels in whole blood and in B and T lymphocytes sorted with antibody-coated magnetic beads. They were not detected in samples collected more than 15 months posttransplantation for 6 of 7 patients. The persistence of residual recipient cells within 1 year posttransplantation is not restricted to male patients receiving a transplant from a female donor because they were also detected in 2 female patients using an allele-specific amplification method for the thyroid peroxydase gene that also has a high sensitivity (0.01%). Our results indicate that at least residual recipient myeloid progenitors and possibly totipotent hematopoietic stem cells may survive intensive pretransplant conditioning regimen and support a transient residual hematopoiesis of the host posttransplantation.

Adolescent↗
PubMed1994

Detection of recipient cells after non T-cell depleted bone marrow transplantation for leukemia by PCR amplification of minisatellites or of a Y chromosome marker has a different prognostic value.

We used polymerase chain reaction amplification of minisatellite sequences (33.6.3, MS51, YNZ22) and of a Y chromosome-specific sequence (DYZ1) to document prospectively chimerism in 23 leukemia patients grafted with non T-cell depleted marrows from HLA-identical sibling donors. Twenty-two patients had a complete hematopoietic chimerism (within the sensitivity limit of the method used: 1%) early (about 1 month) after transplantation and one had detectable residual host cells (partial chimerism). These cells were still present after 8 months, and this patient relapsed 16 months after transplantation. Two patients with early complete chimerism relapsed 16 and 17 months after transplantation. Seven patients died from toxicity or infections and 13 are in clinical remission with a follow-up of 16 to 48 months. Nine male patients grafted with the marrow from a female donor were also studied by amplification of the DYZ1 marker (0.01% sensitivity). In all nine cases, residual male nucleated cells were detected early and up to 1 year after transplantation. These results suggest that the detection of persistent residual recipient cells above a 1% level might be predictive of relapse but that the detection of such cells in a 0.01-1% range is probably unrelated to relapse and does not seem to influence the outcome of the transplantation procedure.

Bone Marrow Transplantation↗
PubMed1993

Bone marrow transplantation for Fanconi anemia using low-dose cyclophosphamide/thoracoabdominal irradiation as conditioning regimen: chimerism study by the polymerase chain reaction.

Since 1976, patients grafted at the Hôpital Saint-Louis for Fanconi anemia (FA) without evidence of leukemic transformation have been given a uniform conditioning regimen that consisted of low-dose cyclophosphamide (Cy) and thoracoabdominal irradiation (TAI). The use of low-dose Cy raised the question of whether it is sufficient for the establishment of a complete hematopoietic chimerism in all patients. We therefore initiated a study of chimerism early during hematopoietic reconstitution after bone marrow transplantation (BMT) and thereafter in transplanted FA patients. Minisatellite probes were used after DNA amplification by the polymerase chain reaction (PCR). From July 1989 to October 1992, 24 consecutive patients underwent BMT for FA, 19 of whom were assessable for chimerism. Our results using this sensitive technique showed that, among these 19 patients, all but one successfully engrafted. Engraftment was complete early after BMT in 12. The persistence of a small proportion of recipient's cells was detected in six. This partial hematopoietic chimerism was demonstrated to be only transient in at least five of the six patients. The one patient who failed to engraft showed a recipient-type profile for circulating cells early posttransplantation, indicating autologous bone marrow recovery. A second graft in this patient was also rejected. For both transplantations, the patient was grafted from a matched, unrelated donor. Therefore, 17 of 17 patients successfully grafted and with complete follow up data presented complete hematopoietic chimerism, within the sensitivity limit of the method used. In conclusion, lowering the Cy dose in the conditioning regimen of patients with FA could still allow complete engraftment to occur, at least in patients with an identical sibling donor.

Bone Marrow Transplantation↗