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Biomedical subjects

M Posner

Publications and source records attributed to M Posner.

At least 73 records · Page 4Linked to original sources

Ilizarov technique in treatment of congenital hand anomalies. Two case reports.

An Ilizarov apparatus was successfully used in the treatment of a six-year-old child with a radially deviated hand caused by congenital pseudoarthrosis of the distal radius after previous traditional surgery failed. The limb length was restored, the pseudoarthrosis healed, and the deviated hand corrected. A second child, five years old, with Poland's syndrome, had a 90 degrees flexion contracture of the wrist that was treated with the Ilizarov apparatus. The flexion contracture was gradually corrected. It seems that the Ilizarov apparatus can be an important tool in the treatment of complex limb deformities.

Child↗

Development of a radioimmunoassay to bradykinin using monoclonal antibodies.

We report here our success in the preparation of monoclonal antibody directed against bradykinin. We further demonstrate that the preparation is easier and less time-consuming compared to the preparation of polyclonal antibodies. The polyclonal antibody provides a ready source of the reagent very much required in the performance of the kinin radioimmunoassay. Limitation of this reagent was in the fact that it did not attain the desired specificity to distinguish between the kinin peptides. Nevertheless, it is interesting to note that the domains of recognition sites can be very similar for monoclonal or polyclonal response, particularly when the antigen is smaller (molecular size of about 1 Kd) as is the case with bradykinin. Our laboratory produced the first monoclonal antibodies at Brown University. These antibodies were directed to bradykinin in BALB-C mice and could recognize bradykinin, lysyl-bradykinin and met-lysyl-bradykinin. Using this reagent it is possible to develop and validate an RIA which can be utilized to measure total kinins in tissues and body fluids. Although this antibody shows similar specificity as found with the polyclonal antibody, the ease and shorter duration of this preparation may make it a reagent of choice.

Animals↗

Early events of RNA polymerase II transcription initiation.

We have investigated the earliest stages of assembly of an RNA polymerase II transcription complex. General transcription factors from HeLa cells were partially purified and assayed using the adenovirus-2 major late promoter. Preincubation of either all the transcription factors (TF) with the DNA or only the subset consisting of TFIIA, TFIID, and DNA overcame the 15-20 min lag normally observed. The kinetics demonstrate that TFIIA first interacts with the template over a 5 min. period, and then TFIID interacts with the IIA:DNA complex over a 2 min. period. The remainder of the necessary transcription factors then interact with the IIA:IID:DNA complex. There are apparently interactions between IIA and IID, as a pre-incubation of these factors (without DNA) overcomes the lag period. Both IIA:DNA and IIA:DNA:IID interactions are temperature sensitive, resulting in slower kinetics at 0 degree C. Thus, the kinetics of transcription involve activation processes in addition to DNA binding.

Adenoviridae↗

Cerebrospinal fluid aluminum levels following deferoxamine.

Deferoxamine is widely used in the diagnosis and treatment of aluminum toxicity and has a characteristic combination of side effects, including a poorly defined worsening of existing neurologic symptoms. However, to date, no measurement of cerebrospinal fluid (CSF) aluminum concentrations after deferoxamine exist. We report the case of a patient who developed acute neurological deterioration in conjunction with sepsis and elevated serum aluminum levels shortly after renal transplantation. Simultaneous values for blood and CSF aluminum were measured in response to deferoxamine and hemodialysis. The increase in CSF aluminum levels appears to parallel that seen in serum after deferoxamine. We hypothesize that this elevation in CSF aluminum may account for the observed neurologic deterioration after deferoxamine and postulate various pathophysiologic mechanisms that might be involved.

Adult↗

A phase I-II trial of continuous-infusion cisplatin, continuous-infusion 5-fluorouracil, and VP-16 in colorectal carcinoma.

Twenty-nine evaluable patients with colorectal adenocarcinoma were treated in a phase I-II trial of combination chemotherapy with a 72-h continuous infusion of cisplatin (CDDP) and 5-fluorouracil (5-FU) with an infusion of VP-16 given at 24 and 48 h after the start of therapy. There were five (17 +/- 14%) partial responses lasting 2-6 months (median, 3). Three of these responses occurred among the 10 previously untreated patients. The toxicity of this regimen was pronounced. Four of eight patients with severe neutropenia required hospitalization for infections, two of which were life-threatening; one of six patients with severe thrombocytopenia had a life-threatening hemorrhagic complication; and four patients experienced severe, dose-limiting fatigue. These complications occurred principally with CDDP and VP-16 at doses above 27.5 mg/m2/day and 110 mg/m2/dose, respectively. Mucositis occurred in six patients and limited the dose of 5-FU to 1,300 mg/m2/day. Although the response rate appeared to be high in previously untreated patients, the minimal palliative benefit of treatment and the brief duration of the responses do not compensate for the toxicity observed.

Adenocarcinoma↗

Nephrectomy following trauma--impact on patient outcome.

Nephrectomy for trauma is done infrequently due to the success of renal sparing procedures. The purpose of this review was to quantitate the effect of nephrectomy on patient outcome. Over a 5-year period 55 of 783 patients had renal injuries confirmed at trauma laparotomy. Nephrectomy was performed in 14 (25%) of these patients. Thirteen patients had penetrating injuries (12 gunshot wounds, one stab wound) and one patient was the victim of blunt trauma. The average number of associated injuries was 3.6. Three patients exsanguinated intraoperatively. Renal failure (serum creatinine greater than 2.5 mg%) developed in four patients; three required hemodialysis. The average time of onset of renal dysfunction was 3 weeks, and in every case it was preceded by intra-abdominal sepsis. Two patients died, both from multiple organ failure, on postoperative day 25 and 26, respectively. In the seven patients free of renal failure, one patient developed sepsis and subsequently died. Of the eight surviving patients, all had adequate renal function as evidenced by an average blood urea nitrogen of 14 mg%, serum creatinine of 1.3 mg%, and a creatinine clearance of 77 ml/min. Renal failure following nephrectomy for trauma occurs late in the hospital course and is invariably preceded by sepsis. Nephrectomy is a marker of severe intra-abdominal injury, but in itself is not the major determinant of survival.

Abdominal Injuries↗

Efficacy of multimodality therapy in gastric adenocarcinoma.

Multimodality therapy has not reproducibly improved the survival of patients with gastric adenocarcinoma. This is largely because the staging of disease has been imprecise and because the current regimens have only limited efficacy against advanced disease. Until staging is improved and active regimens are found, it will be difficult to identify synergism between surgery and other treatment modalities.

Adenocarcinoma↗

Influence of multimodality therapy on the management of pancreas carcinoma.

Carcinoma of the pancreas has an especially grim prognosis. Only 1-3% of patients survive for 5 years. Radical pancreaticoduodenectomy, especially for minimal disease, is currently the only chance for cure. While radiation therapy does not improve overall survival, it may improve local control following radical resection and decrease pain in locally advanced cancers. Although chemotherapy has led to significant improvements in survival in patients with locally advanced disease, the overall effect is small. When surgery, radiotherapy, and chemotherapy are administered to localized carcinomas in randomized, prospective trials, survival is significantly lengthened. Similar trials in locally advanced, unresectable pancreatic cancer also confirm the concept of synergistic interaction between therapies. Thus, pancreas carcinoma is one neoplasm where multimodality therapy has had a demonstrable, although small effect.

Carcinoma↗