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Biomedical subjects

A Kantor

Publications and source records attributed to A Kantor.

At least 19 recordsLinked to original sources
PubMed2000

Interaction between LIS1 and doublecortin, two lissencephaly gene products.

Mutations in either LIS1 or DCX are the most common cause for type I lissencephaly. Here we report that LIS1 and DCX interact physically both in vitro and in vivo. Epitope-tagged DCX transiently expressed in COS cells can be co-immunoprecipitated with endogenous LIS1. Furthermore, endogenous DCX could be co-immunoprecipitated with endogenous LIS1 in embryonic brain extracts, demonstrating an in vivo association. The two protein products also co-localize in transfected cells and in primary neuronal cells. In addition, we demonstrate homodimerization of DCX in vitro. Using fragments of both LIS1 and DCX, the domains of interaction were mapped. LIS1 and DCX interact with tubulin and microtubules. Our results suggest that addition of DCX and LIS1 to tubulin enhances polymerization in an additive fashion. In in vitro competition assays, when LIS1 is added first, DCX competes with LIS1 in its binding to microtubules, but when DCX is added prior to the addition of LIS1 it enhances the binding of LIS1 to microtubules. We conclude that LIS1 and DCX cross-talk is important to microtubule function in the developing cerebral cortex.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1999

Who represents managed care?

Managed care-related trade associations are more than just legislative advocates. Faced with a competitive marketplace and an overlap in membership from the sheer number of associations, these groups now offer a multitude of services, such as on-line job matching, resource guides, discounts on related professional services, and public relations assistance.

Economic Competition↗
PubMed1998

[Serotonin re-uptake inhibitors as primary therapy for carotid sinus hypersensitivity].

Carotid sinus syndrome is a well-recognized cause of unexplained syncope in older patients, and may, lead to significant morbidity due to trauma from falls. Dual chamber pacing has been shown to be effective in relieving symptoms due to bradycardia, but not due to vasodepressor response. We report an 84-year-old man with recurrent syncope due to carotid sinus hypersensitivity. He was treated only with a serotonin reuptake inhibitor and was symptom-free after 3 weeks of therapy. He has remained symptom-free for the past year.

Aged↗
PubMed1997

Molecular characterization of the replicon of the Pediococcus pentosaceus 43200 pediocin A plasmid pMD136.

The pediocin A-encoding plasmid of Pediococcus pentosaceus 43200, pMD136, was characterized by restriction enzyme analysis. Analysis of its replicon was facilitated by the construction of a probe vector consisting of the Escherichia coli plasmid pSP72 and the cat gene from Staphylococcus aureus plasmid pC194. The replication region of pMD136 was localized on a 1.6-kb EcoRI/BglII fragment. Sequencing analysis revealed a non-coding region, repA, spanning the first 440 bp, followed by an open reading frame, repB, encoding a putative protein of 390 amino acids. The non-coding region contained two sets of 6-bp and two sets of 22-bp direct repeats and two sets of inverted repeats upstream of the open reading frame. Strong homology of the isolated replicon was found to theta-type replicons of Lactococcus lactis plasmids. Segregational stability assay suggested at least two regions as potentially involved in the stabilization of pMD136. The plasmid's strong homology to other theta-type replicons and its relatively high stability suggest that pMD136 belongs to the widespread family of theta-replication plasmids.

Amino Acid Sequence↗
PubMed1997

Large-scale preparation and characterization of recombinant ovine placental lactogen.

To clone ovine placental lactogen (oPL) cDNA, total RNA from sheep placental cotyledon was reverse transcribed and the single-stranded cDNA was PCR-amplified with 5' and 3' primers containing, respectively, NcoI and PstI sites. The oPL cDNA fragment amplified between these two primers extended from A(-1) to the natural stop codon. The PCR product was gel-purified and subcloned into a Puc vector and the insert was sequenced on both strands, revealing several differences relative to the published sequence: S19N, S69N, D129E and R165Q. We assume that these differences can be accounted for by the high level of individual polymorphism, which has been described in detail for PLs of different species. The insert was subcloned into NcoI/ PstI-digested pTrc99A procaryotic expression plasmid and protein expression was induced by isopropyl-1-thio-beta-D-galactopyranoside. Because of low expression, oPL's cDNA was further subcloned into pET8 procaryotic expression plasmid. Its expression in E. coli strain BL21 transformed with this vector yielded 30-40 mg/l. The expressed protein, found in the inclusion bodies, was refolded into a monomer and purified on a Q-Sepharose column to homogeneity. Structural analysis using circular dichroism revealed a spectrum similar to that of human GH (hGH) thereby indicating proper refolding. Gel filtration and binding experiments, including real-time kinetic measurements using the surface plasmon resonance method revealed that oPL forms transient homodimeric complexes with extracellular domains of prolactin receptors from rabbit, rat and bovine and with hGH receptor. The purified oPL was biologically active in an Nb2-11C cell proliferation bioassay, in its ability to stimulate beta-casein synthesis in explants of ovine and rabbit mammary gland and fat synthesis in explants of bovine mammary gland, and in a proliferation assay using FDC-P1 cells transfected with rabbit or hGH receptors.

Animals↗
PubMed1995

Femoral torsion after interlocked nailing of unstable femoral fractures.

OBJECTIVE: The determination of rotation of the femur during intramedullary nailing procedures can be difficult, particularly when the fracture pattern does not lend itself to interdigitation. We studied 22 patients who had isolated femur fractures treated by closed intramedullary nailing to determine the degree of malrotation introduced at the time of surgery. DESIGN AND METHODS: Anteversion of the affected and normal femora was determined by a standard computed tomography (CT) torsion study. The range of motion of the hip was measured in the prone position. Foot progression angles (FPAs) were measured in 14 patients who were fully ambulatory for at least 6 months. MAIN RESULTS: The average malrotation of the fractured femur was 16 degrees (4 to 61 degrees). The median malrotation was 14 degrees. The differences in CT-measured anteversion (delta A), FPA (delta FPA), internal rotation (delta IR), and external rotation (delta ER) between the affected and normal sides were determined. Linear regression was used to analyze delta A with delta FPA, delta IR, and delta ER. Changes in internal and external rotation as determined by physical exam had a stronger correlation with delta A than did delta FPA. This indicates that malrotation of the femur is accommodated for during gait. CONCLUSIONS: Based on this data, we found that anteversion of the normal femur can be determined in the operating room using the image intensifier and can be duplicated on the fractured side using the described technique in cases where comminution prevents fragmentational alignment. This method has been used for 12 patients in a prospective trial, and malrotation has been kept to under 10 degrees in all cases.

Adult↗
PubMed1995

Nonoperative salvage of computed tomography-diagnosed splenic injuries: utilization of angiography for triage and embolization for hemostasis.

OBJECTIVES: The aims of this study were to determine if angiographic findings can be used to predict successful nonoperative therapy of splenic injury and to determine if coil embolization of the proximal splenic artery provides effective hemostasis. METHODS: Splenic injuries detected by diagnostic imaging between 1981 and 1993 at a level I trauma center were prospectively collected and retrospectively reviewed after management by protocol that used diagnostic peritoneal lavage, computed tomography (CT), angiography, transcatheter embolization, and laparotomy. Computed tomography was performed initially or after positive diagnostic peritoneal lavage. Angiography was performed urgently in stabilized patients with CT-diagnosed splenic injuries. Patients without angiographic extravasation were treated by bed rest alone; those with angiographic extravasation underwent coil embolization of the proximal splenic artery followed by bed rest. RESULTS: Patients (172) with blunt splenic injury are the subject of this study. Twenty-two patients were initially managed operatively because of associated injuries or disease (11 patients) or because the surgeon was unwilling to attempt nonoperative therapy (11 patients) and underwent splenectomy (17 patients) or splenorrhaphy (5 patients). One hundred fifty of 172 consecutive patients (87%) with CT-diagnosed splenic injury were stable enough to be considered for nonoperative management. Eighty-seven of the 90 patients managed by bed rest alone, and 56 of 60 patients treated by splenic artery occlusion and bed rest had a successful outcome. Overall splenic salvage was 88%. It was 97% among those managed nonoperatively, including 61 grade III and grade IV splenic injuries. Sixty percent of patients received no blood transfusions. Three of 150 patients treated nonoperatively underwent delayed splenectomy for infarction (one patient) or splenic infection (two patients). CONCLUSIONS: (1) Hemodynamically stable patients with splenic injuries of all grades and no other indications for laparotomy can often be managed nonoperatively, especially when the injury is further characterized by arteriography. (2) The absence of contrast extravasation on splenic arteriography seems to be a reliable predictor of successful nonoperative management. We suggest its use to triage CT-diagnosed splenic injuries to bed rest or intervention. (3) Coil embolization of the proximal splenic artery is an effective method of hemostasis in stabilized patients with splenic injury. It expands the number of patients who can be managed nonoperatively.

Adolescent↗
PubMed1994

Radiation therapy in epidemic, AIDS-related Kaposi's sarcoma in southern Africa.

AIMS AND BACKGROUND: Acquired Immunodeficiency Syndrome (AIDS) associated Kaposi's Sarcoma (EKS) is widely spread in the Southern African Region. No large studies concerning the role of radiation therapy in the Southern African variant of EKS have been reported to date. METHODS: Over a 10 year period (1982-1992) 25 patients with EKS (disseminated skin involvement) were treated primarily with radiation therapy at the Johannesburg General Hospital. Radiation fields were individually tailored to the extent of the disease. Total administered doses ranged between 8-12 Gy (single fraction) to 24-30 Gy fractionated over 2-3 weeks. RESULTS: Overall response and symptomatic relief rates were 72% and 80%, respectively. Toxicity was mild and manageable. CONCLUSIONS: Our retrospective analysis supports the use of radiation therapy for the Southern African type of EKS.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Radiation therapy in an elderly African population with Kaposi's sarcoma.

There are no published studies on the efficacy of modern radiation therapy in elderly populations with the endemic African type of Kaposi's sarcoma (AKS). The present retrospective analysis of 20 elderly AKS patients treated by radiotherapy attempts to supply information relevant to the older age group. It demonstrates that excellent symptomatic relief with minimal side effects can be attained and suggests that the role of radiotherapy as the treatment of choice in this particular group should be emphasized.

Africa↗
PubMed1994

Malignant lymphoma with primary cardiac manifestations: a case report.

This case report describes a 29-year-old black patient presenting with right heart failure secondary to massive lymphomatous cardiac involvement. Additional sites of involvement included mesenteric lymph nodes and the small bowel. Malignant lymphoma with primary cardiac manifestations is very rare and follows an aggressive course. The importance of early diagnosis and commencement of immediate therapy is emphasized.

Adult↗
PubMed1994

Classical Kaposi's sarcoma in Caucasians in Africa--experience at the Johannesburg Hospital (1978-1992).

The data are scant concerning classical Kaposi's sarcoma (CKS) among the Caucasian population of Africa. A description of the clinical features of 15 such patients, treated and followed up at the Johannesburg General Hospital over a 14-year period (1978-1992) is presented. All patients were negative for the human immunodeficiency virus. After a mean follow-up of 50 months (range: 7-168 months), 2 patients are alive with absent or minimal disease; 1 patient is alive with stable disease and 1 has active disease involving his extremities. Three patients were lost to follow-up but had minimal or no disease when last seen. Five patients died of unrelated causes but also had minimal or no disease at their last visit. One patient died of sepsis related to active KS. Only two patients died of progressive KS. No alterations in humoral or cellular immunity were demonstrated in 2 patients with persistent disease. Four (27%) patients developed lymphoproliferative disorders including non-Hodgkin's lymphoma, Waldenström's macroglobulinemia, Hodgkin's disease and Castleman's disease (angiofollicular lymph node hyperplasia) preceding or following the diagnosis of CKS. These data confirm the indolent nature and good outcome of the classical form of Kaposi's sarcoma among Caucasians in the southern African region. The marked association between CKS and lymphoproliferative disorders warrants a long-term awareness and continued monitoring for these complications.

Adult↗