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Biomedical subjects

E C Martin

Publications and source records attributed to E C Martin.

At least 19 recordsLinked to original sources
PubMed1991

Drosophila genes Posterior Sex Combs and Suppressor two of zeste encode proteins with homology to the murine bmi-1 oncogene.

The Polycomb group (Pc-G) genes are needed to maintain expression patterns of the homeotic selector genes of the Antennapedia (Antp-C) and bithorax (bx-C) complexes, and hence for the maintenance of segmental determination. We report the predicted protein sequence of the Pc-G gene Posterior Sex Combs (Psc), and of the neighbouring and related gene Suppressor two of zeste (Su(z)2). Both genes encode large proteins that contain a 200 amino-acid domain identical over 37.4% that is also conserved in the murine oncogene bmi-1. At the amino terminus of this domain is a cysteine-rich sequence that has been proposed as a novel type of zinc finger.

Amino Acid Sequence↗
PubMed1991

Phenotypic consequences and genetic interactions of a null mutation in the Drosophila Posterior Sex Combs gene.

The Posterior Sex Combs (Psc) gene of Drosophila is a member of the Polycomb (Pc) group of transregulatory genes. Previous analyses of the function of this gene in Drosophila embryogenesis have been hampered by the lack of a null mutation. We recently isolated a mutation that deletes the 5' end of the Psc gene. This allele appears to be a null mutation, and we have used it to determine the Psc zygotic null phenotype and to look at the interactions of a null allele of Psc with five other Pc group mutations. We find evidence for transformations along both the anterior-posterior and dorsal-ventral axes in embryos of a variety of genotypes that include a null mutation in Psc. The phenotypes of embryos that are doubly mutant for a null allele of Psc and a mutation in a second Pc group gene show dramatic synergistic effects, but in their specifics they are dependent on the identity of the second Pc group gene. This is different from the relatively uniform phenotypes seen among double mutants that contained the allele Psc1, which has both gain and loss of function properties. The differences in the phenotypes of the doubly mutant embryos allow us to eliminate one class of molecular models to explain the dramatic synergism seen with mutations in this group of genes.

Animals↗
PubMed1991

Molecular genetics of the Posterior sex combs/Suppressor 2 of zeste region of Drosophila: aberrant expression of the Suppressor 2 of zeste gene results in abnormal bristle development.

We report the molecular characterization of the Posterior sex combs-Suppressor 2 of zeste region of Drosophila melanogaster. The distal breakpoint of the Aristapedioid inversion divides the region into two parts. We have molecularly mapped the lesions associated with several loss of function mutations in the Polycomb group gene Posterior sex combs (Psc) proximal to this breakpoint. In addition, we have found that lesions associated with several loss of function mutations in the Suppressor 2 of zeste [Su(z)2] gene lie distal to this breakpoint. Since the breakpoint does not cause a loss of function in either gene, no essential sequences are shared by these two neighboring genes. There are three dominant gain of function mutations in the region that result in abnormal bristle development. We find that all three juxtapose foreign DNA sequences upstream of the Su(z)2 gene, and that at least two of these mutations (Arp1 and vgD) behave genetically as gain of function mutations in Su(z)2. Northern and in situ hybridization analyses show that the mutations result in increased accumulation of the Su(z)2 mRNA, which we argue is responsible for the bristle loss phenotype.

Animals↗
PubMed1990

Obstruction of the Roux limb after portoenterostomy for biliary atresia: a delayed complication.

We report the case of a 5-year-old girl who underwent a Kasai portoenterostomy for extrahepatic biliary atresia. The conduit was exteriorized until 11 months of age. She was doing well, with stable portal hypertension until she suddenly developed jaundice, acholic stools, and bacteremia not responsive to a course of steroids and intravenous antibiotics. Suspecting obstruction at the site of the previously exteriorized anastomosis, a percutaneous cannulation of the conduit was performed. Catheterization of the conduit obstruction unkinked it and reestablished bile flow. She has remained anicteric with stable liver function.

Anastomosis, Roux-en-Y↗
PubMed1990

Gianturco-Rosch biliary stents: preliminary experience.

Results of long-term follow-up are reported for nine patients who underwent placement of Gianturco-Rosch expandable metallic stents. Seven patients had malignant disease. The average duration of patency was 7 months. In one patient with inactive primary sclerosing cholangitis (PSC), the stents remained patent at 22 months, but recurrent stent closure was seen in a second patient with PSC. In the patient population studied, no advantages were seen with use of the stents; however, they may have an application in certain patients with benign disease.

Adenoma, Bile Duct↗
PubMed1989

Maintaining quality of life after palliative diversion for malignant ureteral obstruction.

The records of 71 consecutive patients who underwent percutaneous nephrostomy for malignant ureteral obstruction were reviewed. The average post-nephrostomy survival time was seven months, of which 25% was spent in the hospital. When comparing these figures to older studies of open nephrostomy, the percutaneous procedure is associated with less morbidity and an increased percentage of time spent at home (75% compared to 36%). Long-term survival, however, is still poor, with only 25% of patients alive at one year. We suggest that the criteria previously adopted for open nephrostomy generally remain appropriate for patients being considered for percutaneous urinary diversion.

Adult↗
PubMed1989

Percutaneous drainage of intra-abdominal abscesses following abdominal trauma.

Between January 1, 1984, and June 30, 1987, we performed percutaneous catheter drainage (PCD) of 28 intra-abdominal abscesses in 21 postoperative trauma patients. During this period only three patients had abdominal re-exploration for drainage of abdominal abscess. The PCD patients were predominantly young men who had sustained penetrating abdominal injuries (81% GSW or SW; 19% MVA). Seventeen (81%) patients had multiple abdominal organ injuries with the colon being the most frequently injured (57%). Multiple abscesses were identified in 33% of the patients. All 21 patients had successful treatment of their abscesses by PCD alone. There was one complication (4.8%) from PCD (pneumothorax) and no deaths in this group. Our data suggest that in most cases, PCD can be safe, effective, and definitive treatment for postoperative intra-abdominal abscesses following abdominal trauma. We recommend PCD in all postoperative trauma patients who develop accessible abdominal abscesses before resorting to re-exploration.

Abdominal Injuries↗
PubMed1989

Percutaneous transjejunal approaches to the biliary system.

The authors report 10 cases in which various retrograde manipulations in the biliary tract were performed via percutaneous access from the jejunum in patients who had previously undergone Roux-Y biliary surgery. The first cases involved attempted retrograde cholangiography through the jejunal limb in children who had undergone Roux-Y portoenterostomies, followed by cases of percutaneous placement of U tubes and an attempt at percutaneous creation of an hepaticojejunostomy. When a limb from the Roux-Y has been brought to the skin and marked with clips, jejunal puncture is easily performed, is well tolerated by patients, and may be repeated frequently. It also appears that after Roux-Y choledochojejunostomy, the Roux-Y limb is fixed and may be punctured with relative safety. Since access from below is more favorable for intrabiliary manipulations, the transjejunal approach expands the armamentarium of the interventional radiologist in the combined radiologic and surgical management of complex biliary disease.

Adolescent↗
PubMed1989

Total occlusions of the femoropopliteal artery: high technical success rate of conventional balloon angioplasty.

Seventy patients 48-93 years of age underwent standard percutaneous transluminal angioplasty (PTA) for femoropopliteal artery occlusions 1-10 cm long. PTA was accomplished through an antegrade puncture of the common femoral artery. The angiographic criterion for technical success was restoration of the vessel lumen with no significant residual stenosis. The authors report technical success in 64 (91%) of their patients, an improvement over a technical success rate of 74% in their previous series of 46 other PTA patients with occlusions 1-20 cm long. In this series, no complications related to PTA necessitated emergency surgical intervention. Refinements in PTA can be attributed to changes in patient selection and medication, improvements in balloon catheters and guide wires, and greater proficiency on the part of angiographers. This update reflects currently achievable results with standard angioplasty techniques, and it is against such results that all new vascular recanalization techniques, including laser-assisted PTA, should be compared.

Aged↗
PubMed1987

Percutaneous creation of a hepaticojejunostomy.

A procedure is described whereby a direct anastomosis may be created percutaneously between the biliary system and a Roux-en-Y limb; in effect a percutaneous hepaticojejunostomy. Although it will have limited applications, it represents a further extension of percutaneous techniques in the biliary system for complex problems.

Abscess↗
PubMed1987

Hepatic neurofibromatosis, malignant schwannoma, and angiosarcoma in von Recklinghausen's disease.

Liver involvement by neurofibromatosis is rare. This report describes a young man with von Recklinghausen's disease and hepatic neurofibromas who developed a large right hepatic lobe malignancy and died of massive intratumor hemorrhage. Postmortem examination showed the tumor to be composed of both malignant schwannoma and angiosarcoma and to have arisen from contiguous neurofibromas in portal tracts. Widespread pulmonary metastases consisted of the angiosarcomatous elements alone. The expression of malignant schwannoma and angiosarcoma phenotypes in this tumor may be related to a common histogenesis from cells of the neural crest.

Adult↗
PubMed1987

Epidemiology of infection by nontuberculous mycobacteria. VII. Absence of mycobacteria in southeastern groundwaters.

Using the fluorochrome auramine-O, direct microscopic counts of log phase cells of Mycobacterium avium, M. intracellulare, and M. scrofulaceum (MAIS) group showed excellent correlations with viable spread-plate counts. Accordingly, an enumeration of total acid-fast and MAIS cells by stain and culture (respectively) in groundwaters from three United States regions that differ in their incidence of human infection by MAIS was undertaken. Of 30 state-monitored, undisinfected wells, 11 were in Georgia coastal plain (high incidence), 10 were in the Virginia coastal plain (intermediate incidence), and 9 were in Montgomery County, Virginia (low incidence). Total acid-fast cells ranged widely between 280 to 5,367 per ml among the groundwaters, and with one exception showed no correlations or trends between regions of different incidence of human infection, or to total bacterial cell counts or colony-forming units. The exception was that the proportions of acid-fast cells relative to total cells were higher in the Georgia groundwaters. However, despite the relatively high auramine-O counts, few mycobacteria were recovered by culture. Of 12 wells yielding mycobacteria, 9 yielded rapidly growing and 4 slowly growing mycobacteria. Only one well in Montgomery County, Virginia (region of low incidence) yielded a MAIS isolate, albeit at low density. This research supports the conclusion that clean groundwaters are unlikely sources of MAIS infection in humans in the southeastern United States.

Georgia↗
PubMed1986

Percutaneous removal of large gallstones.

Two patients are described in whom large gallstones, up to 4 cm in diameter, were removed percutaneously. The technique has some relevance to high risk patients with surgical cholecystotomies in whom elective cholecystectomy may be deferred if all the calculi can be removed. It may also be relevant if "percutaneous cholecystectomy" is ever developed clinically.

Aged↗