Understanding proton emission in central heavy-ion collisions.
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Journal Article↗
Biomedical subjects
L Martin
Publications and source records attributed to L Martin.
beta-Amyloid peptide-derived, oxygen-dependent free radicals inhibit glutamate uptake in cultured astrocytes: implications for Alzheimer's disease.
beta-Amyloid (A beta), the central constituent of senile plaques in Alzheimer's disease (AD) brains, was shown by us recently to generate free radicals in an oxygen dependent mechanism. A beta-derived free radicals were detected directly using electron paramagnetic resonance (EPR) spin trapping techniques employing the spin trap phenyl-alpha-tert-butylnitrone (PBN). We have extended these studies to investigate the nature of the oxyradicals derived from A beta peptides, and we show that these free radicals are able to inhibit glutamate uptake in cultured astrocytes. An implication of inhibited astrocyte glutamate uptake in brain is increased extracellular levels of glutamate, which is excitotoxic to neurons. These results support the hypothesis that A beta neurotoxicity in AD may be due in part to A beta-derived, oxygen-dependent free radical inhibition of glutamate uptake.
Alzheimer Disease↗
cDNA sequence of the murine synaptonemal complex protein 1 (SCP1).
We isolated and sequenced cDNAs for the murine synaptonemal complex protein 1 (SCP1). The whole cDNA sequence displays respectively 93% and 90% identity with the previously reported rat and hamster cDNAs. We show, however, that the encoded amino acid sequence extends for an additional stretch of 51 residues at its amino-terminal end.
Amino Acid Sequence↗
Non-fasting chylomicronaemia in breast implant patients.
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Breast Implants↗
cDNA cloning and characterization of lamina-associated polypeptide 1C (LAP1C), an integral protein of the inner nuclear membrane.
Lamina-associated polypeptides 1A-1C (LAPs1A-1C) are related integral membrane proteins of the inner nuclear membrane that bind to both A- and B-type lamins and have a putative role in the membrane attachment and assembly of the nuclear lamina. In this study, we have cloned a cDNA encoding LAP1C. The DNA sequence predicts a 506-amino acid protein of largely hydrophilic character with a single membrane-spanning region between residues 311-333. Mapping of the epitope recognized by the anti-LAP1 monoclonal antibody RL13 indicates that the hydrophilic domain containing residues 1-310 is exposed to the nucleoplasm and thus that LAP1C is a type II integral membrane protein. A second class of LAP1 cDNAs was isolated that contains two protein-coding nucleotide insertions in the LAP1C sequence. These probably encode parts of LAPs1A and/or -1B, suggesting that LAP1 isotypes arise from alternative splicing. Immunoblot analysis of mouse P19 teratocarcinoma cells and the P19MES-differentiated derivative of the latter suggest that LAP1 isotypes are differentially expressed during development, similar to members of the nuclear lamin family. Since the different LAP1 isotypes appear to bind lamins with different affinities, these changes in expression could be important for developmentally regulated alterations in nuclear structure.
Amino Acid Sequence↗
Blood flow in breast cancer and fibroadenoma estimated by colour Doppler ultrasonography.
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Axilla↗
Fine-needle aspiration cytology of superficial angiomyxoma (myxoid perifollicular fibroma): report of a case.
A case of superficial angiomyxoma arising in the areola of a 49-yr-old woman is presented, including both fine-needle aspiration cytology (FNAC) and histological study. The aspirate yielded a rich myxoid background with isolated fusiform cells, showing oval, monomorphic nuclei with minimal atypia. Sometimes these cells were arranged in small fragments without any specific pattern. The absence of mitotic figures, atypia, or cutaneous and breast epithelium suggested a benign myxoid stromal neoplasm. The final diagnosis was established on the excised mass by histopathologic study. The report of this entity in FNAC and the differential diagnosis with other myxoid lesions are discussed, and the feasibility of its cytological diagnosis by FNAC, helped by appropriate clinical information.
Adult↗
Evaluating the Dialine vascular prosthesis knitted from an alternative source of polyester yarns.
The sudden and unilateral decision by E. I. DuPont de Nemours & Co., Inc., to withdraw its polymers for use in implantable devices has presented the medical device industry with an immediate and serious challenge to find alternative sources of biomaterials. In France, the company Cardial S.A. has already taken steps to find an alternative polyester yarn to replace Dacron by developing a new arterial prosthesis knitted from polyester yarns supplied by Rhône-Poulenc Fibres. This article describes an in vitro and in vivo study of this French device, called the Dialine prosthesis, with a view to determining its relative performance compared to current American and British prostheses, which rely on DuPont's Dacron yarn. In addition to analyses of the morphology and textile structure, and measurements of its physical and chemical properties, the Dialine graft was implanted as a thoracoabdominal bypass in dogs for periods ranging from 4 h to 6 months. In addition to our pathologic and histologic observations, we cleaned and evaluated the explanted prostheses for in vivo changes in dimensions, strength, and crystalline microstructure. The Dialine graft was found to differ structurally from other polyester prostheses because it is warp-knitted from a mixture of flat and texturized yarns with finer filaments. Its denser structure has a lower water permeability, greater flexibility and ease of handling, satisfactory strength, and dimensional stability, and it presents different textures on its luminal and external surfaces. The in vivo trial demonstrated that it has excellent biocompatibility and biostability over 6 months. With no thrombi observed on the luminal surface after 3 months, it has a faster rate of healing, generates compact external and internal capsules with a thinner neointima, and has an overall milder inflammatory response than is normally observed with Dacron-based prostheses.
Angiography↗
Polyvinylidene fluoride (PVDF) as a biomaterial: from polymeric raw material to monofilament vascular suture.
This study identified the effects of various manufacturing processes on the crystalline microstructure, mechanical properties, and biocompatibility of a polyvinylidene fluoride (PVDF) suture. To achieve this, changes in the crystalline microstructure and the tensile behavior of PVDF monofilaments were monitored in vitro after different thermal processing, coloration, and sterilization treatments. In addition, the in vivo biocompatibility of the manufactured and sterilized PVDF suture was assessed by using it to anastomose a preclotted polyester vascular prosthesis as a thoracoabdominal bypass in a series of dogs. The tissue response was followed by histologic and scanning electron microscopy over implantation periods ranging from 4 h to 6 months. Differential scanning calorimetry and infrared spectroscopy (FTIR-ATR) showed that thermal processing and the addition of a coloring agent had a direct effect on modifying the crystalline microstructure and hence changing the mechanical properties. For example, thermal processing converted some of the alpha phase into the beta and gamma polymorphs, whereas coloration led only to a major increase in the beta-to-alpha ratio. The tensile properties were found to be optimized when the relative proportion of the beta and gamma phases combined compared to the alpha form gave rise to an FTIR A509/A532 absorption ratio between 4.0 and 4.5. Sterilization was found to cause some modifications to the crystalline microstructure near the surface of the monofilaments, but it did not change their mechanical properties. Pathologic examination of the anastomotic regions after different periods of implantation revealed a minimal cellular response, with no mineralization, intimal hyperplasia, or excessive fibrous tissue reaction. This good biocompatibility, together with other desirable characteristics such as ease of manipulation and satisfactory mechanical strength, makes PVDF an attractive alternative monofilament suture material for cardiovascular surgery.
Animals↗
Ovarian and uterine lymphatic drainage in Australian flying-foxes (genus Pteropus, suborder Megachiroptera).
Ovarian lymphatics of flying-foxes were traced to determine if they could transport hormones directly from ovary to ipsilateral uterine horn, thereby stimulating the localised endometrial growth which is characteristic of these animals. Intra-ovarian injections of ink and serial histological sections did not reveal any such connection. All major ovarian lymphatics and those from the cranial tip of each uterine horn drain cranially, terminating in 1 or 2 lymph nodes lying caudal to the ipsilateral kidney. For much of their course, the major ovarian lymphatics run in the adventitia of the ovarian venous sinus. This sinus encloses the coiled ovarian artery, which provides the major blood supply to the cranial end of the ipsilateral uterine horn. Some fine ovarian lymphatics run in the adventitia of the coiled ovarian artery. The enclosure of the coiled ovarian artery by the ovarian venous drainage is thought to provide the main route for transfer of steroids from ovarian vein to ovarian artery and thence to ipsilateral uterine horn. The ovarian lymphatics described here do not bypass the vascular pathway but provide an additional route for counter- or cross-current transfer of ovarian steroids to the ovarian arterial supply to the uterus.
Animals↗
Changes induced by eccentric training on force-velocity relationships of the elbow flexor muscles.
The aim of this study was to examine the effects of a short term eccentric training period on force-velocity relationships of the elbow flexor muscles. From a muscle model, the maximal shortening velocity Vo(x) and the af parameter which varies according to the curvature of the force-velocity relationship of the muscle were determined. Sixteen volunteer subjects divided into 2 groups participated in this study (Group Eccentric GE, n = 8; Group Control GC, n = 8). The subjects performed, on an isokinetic ergometer, 2 maximal concentric elbow flexions at different angular velocities (60, 120, 180, 240, 300, 360 degrees s-1) and held maximal and submaximal isometric actions at an elbow flexion angle of 90 degrees. Under isometric conditions, myoelectrical activity (EMG) of the biceps was recorded and quantified as a RMS value. All tests were performed before and after training sessions. Training was conducted 3 times a week for 4 weeks by the GE, and included 6 x 5 eccentric actions with a load of 100% of 1 RM. After training and for the GE, the af parameter and Vo(x) increased significantly (p < 0.05). These changes were accompanied by a significant increase (p < 0.05) of the RMS value of the maximal isometric action. This evolution towards faster characteristics for the elbow flexor muscles after training could be partly due to nervous adaptation.
Elbow↗
Penetrating trauma and emergency surgery in patients with AIDS.
BACKGROUND: Several recent publications have suggested that emergency surgery in patients with acquired immunodeficiency syndrome (AIDS) is associated with extremely high morbidity and mortality. PATIENTS AND METHODS: We reviewed the records of 21 patients with AIDS at the University of Miami/Jackson Memorial Medical Center in Miami, Florida, who underwent 24 emergency operations after sustaining penetrating trauma RESULTS: Nineteen patients (90%) presented with gunshot wounds and 2 (10%) presented with stab wounds. Two patients underwent multiple surgical procedures to control hemorrhage from a complex liver injury and to drain a retained hemothorax, respectively. After surgery, patients were managed according to standard protocols, the same as those for non-AIDS patients. Wound infection was present in 4 patients (19%), and occurred only in patients with < 100 CD4+ cells/microL. Fifty-seven percent of patients had no prior knowledge of having AIDS or being seropositive for the human immunodeficiency virus. One patient died after surgery and 18 patients (86%) were still alive 6 months after discharge. CONCLUSIONS: As the AIDS epidemic grows, general surgeons will be treating an increasing number of these patients. A low morbidity and mortality can be obtained with standard surgical care and techniques. Complications are not uncommon and should be treated as in any other surgical patient, unless it is a terminal condition or that posture runs against the patient's stated views or advance directives.
Acquired Immunodeficiency Syndrome↗
Peripheral plasma progesterone concentrations in pregnant and non-pregnant greyheaded flying-foxes (Pteropus poliocephalus) and little red flying-foxes (P. scapulatus).
Blood was collected from breeding-season and pregnant P. poliocephalus females shot in the wild and from captive pregnant and ovariectomized P. poliocephalus and P. scapulatus females. Peripheral plasma progesterone concentrations measured by radioimmunoassay were similar to those obtained by gas chromatography-mass spectroscopy: in intact non-pregnant P. poliocephalus females without corpora lutea (CLs) values ranged from 2 to 30 ng mL-1; after ovariectomy, they ranged from 1 to 85 ng mL-1. A significant source of progesterone in these bats may be the adrenal. In P. poliocephalus, peripheral plasma progesterone concentrations showed relatively little change over the breeding season or in early pregnancy when a CL formed, but increased from mid pregnancy to reach 200-800 ng mL-1 in late pregnancy. A mid-pregnancy ovary with CL contained 2.80 ng progesterone whereas the contralateral ovary contained 0.13 ng. Overall, CL size decreased during pregnancy and was negatively correlated with plasma progesterone concentrations. In late pregnancy, the main source of progesterone appears to be the placenta; plasma concentrations increase with placental growth and are significantly correlated with placental weight, and placentas contain 4-8 micrograms progesterone g-1. There was no evidence that progesterone concentrations fall before parturition. Limited observations indicated that peripheral progesterone concentrations follow similar patterns in P. scapulatus.
Animals↗
Acalculous cholecystitis: the use of diagnostic laparoscopy.
Acalculous cholecystitis (AC) carries a high mortality in the critically ill patient. This is partly due to the delay in its diagnosis. Clinical diagnostic examinations are often misleading. The purpose of our study was to evaluate the use of laparoscopy as a diagnostic tool in the evaluation of the critically ill patient suspected of having AC. From May 1993 to January 1994, we evaluated 10 critically ill patients. Mean age was 56 years (range 17-90 years). Nine of the patients were trauma victims (8 blunt, 1 penetrating). The other patient was postcoronary bypass surgery. The laparoscopy was done after a mean of 15 days (range 6-54 days) after ICU admission. All patients were receiving ventilatory support, and all patients had elevated temperatures of greater than 38.5 degrees C. Five patients had abdominal tenderness, and 6 had elevated liver function tests (LFT). Six laparoscopies were done under local anesthesia and IV sedation at the bedside, and 4 were done in the operating room. All patients tolerated the procedure well with no complications. The laparoscopic findings were gangrenous cholecystitis in 2 patients. They both underwent laparoscopic cholecystectomies in the operating room. We elected to drain a very distended gallbladder in 1 patient, who eventually was found to have an empyema of the chest. The other 7 examinations were normal. Six of these patients recovered and were discharged. Our results suggest that laparoscopy can be used in the diagnosis of acalculous cholecystitis. Its positive and negative findings are valuable in the treatment of the critically ill. It can be done safely at the bedside.
Adolescent↗
Vl-linker-Vh orientation-dependent expression of single chain Fv-containing an engineered disulfide-stabilized bond in the framework regions.
Single chain Fv fragments (scFv) derived from an antibody, MAb 174H.64 (Tru-ScintRSQ kit, Biomira), were constructed in both orientations, i.e. Vh-linker-Vl and Vl-linker-Vh, but only the latter form could be expressed and secreted in the recombinant Pichia pastoris system. The secreted scFv protein showed specific anti-idiotype binding activity. Additionally, the molecular graphic modeling has been used to identify a possible site for the introduction of an interchain disulfide bond in the framework region of Fv. These Cys-modifications of the sites were done using a method of PCR-mediated mutagenesis. The engineered protein (disulfide-stabilized Fv: dsFv) was expressed and tested for its binding activity. It was found that dsFv was as active as the corresponding scFv and more stable as determined by competitive radioimmunoassay.
Amino Acid Sequence↗
Negative laparotomy in abdominal gunshot wounds: potential impact of laparoscopy.
OBJECTIVE: To evaluate the morbidity and hospital stay resultant from negative exploratory laparotomy (NL) for abdominal gunshot wounds (ABGSWs) and the potential impact the use of diagnostic laparoscopy (DL) could have on these variables. DESIGN: A retrospective study was conducted. MATERIALS AND METHODS: The charts of all patients with ABGSWs over a 4-year period were reviewed. Data was collected on injuries, rate of NL, morbidity and hospital stay. This was compared to a subsequent group of patients with ABGSWs managed with a DL protocol. MEASUREMENTS AND MAIN RESULTS: Over a 4-year period, 817 patients had exploratory laparotomy (EL) for ABGSWs. The NL rate was 12.4% (101 of 817); 69 of these patients had no associated injury or other procedures. They had a 22% morbidity and an average hospital stay of 5.1 days. Subsequently, 85 patients with ABGSWs underwent DL. This group was similar to the EL group and would have undergone EL prior to the introduction of DL at our institution. In this group, 34 patients had no associated injury or other procedures. They had a 3% morbidity, and their average hospital stay was 1.4 days. The morbidity and hospital stay were statistically significantly reduced (p < 0.01) in patients with negative DL versus NL. CONCLUSIONS: These data demonstrate that NL is associated with a high morbidity and long hospital stay. The use of DL can reduce the rate of NL, and result in lower morbidity and shorter hospital stay in patients with ABGSWs.
Abdominal Injuries↗
Laparoscopy in 121 consecutive patients with abdominal gunshot wounds.
OBJECTIVE: The purpose of this study was to evaluate the sensitivity, specificity, and predictive value of diagnostic laparoscopy (DL) in a large group of stable patients with abdominal gunshot wounds (ABGSWs). DESIGN: This study was a prospective case series developed by management protocol. MATERIALS AND METHODS: In a 2 1/2-year period, DL was performed in 121 consecutive patients who were hemodynamically stable with ABGSWs and met protocol criteria. This represented 18% of all patients with ABGSWs seen in this period at the Ryder Trauma Center. The evaluation was conducted to determine peritoneal violation, the presence of intra-abdominal blood, and the need for exploration. MEASUREMENTS AND MAIN RESULTS: There were 42 (35%) positive and 79 (65%) negative DLs. In patients with positive DL, 39 (92.8%) had exploratory laparotomy. In this group, 32 (82%) had therapeutic laparotomy, 6 (15.4%) had nontherapeutic laparotomy, and 1 (2.5%) had a negative laparotomy. In this patient, DL was felt to be inadequate by the attending surgeon, although no penetration or intraperitoneal blood were present, and a negative laparotomy was done. This represents a failure rate of 0.8%. There were 3 (7.2%) positive DLs, in whom laparotomy was not performed. These patients had isolated nonbleeding liver injuries, and nontherapeutic laparotomy was successfully avoided. The negative DL group was divided into 47 patients (60%) with isolated ABGSWs, and 32 patients (40%) with associated injuries, mostly orthopedic and thoracic. There were no false-negative DLs and no delayed laparotomies in these 121 patients. There was no mortality in this study group. The sensitivity for peritoneal penetration was 100%, and the specificity was 98.7%. The positive predictive value was 97.6%, and the negative predictive value was 100%. In deciding on need for laparotomy (i.e., injury requiring repair), DL had a positive predictive value of 82%; more importantly, the negative predictive value was 100%. CONCLUSIONS: In stable patients with ABGSWs and questionable intra-abdominal injury, DL can be safely used. It is highly sensitive and specific. It can effectively reduce the incidence of negative and nontherapeutic laparotomies, and the overall morbidity and hospital stay in this group of patients.
Abdominal Injuries↗
Susceptibility to beta-lactam agents of Yersinia enterocolitica biotype 4, serotype O3 isolated in various parts of the world.
Forty-eight human isolates of Yersinia enterocolitica of biotype 4, serotype O3 from various parts of the world were examined for susceptibility to 13 beta-lactam agents. The intracellular beta-lactamases of each of the 48 strains were examined. Isolates from Europe, Asia and Brazil (phage type VIII) or South Africa and Hungary (phage type IXa) produced both enzyme A and enzyme B, whereas isolates from New Zealand and Australia (phage type IXb) lacked the cephalosporinase enzyme B. Among the seven strains isolated in Canada belonging to phage type IXb, three strains expressed only enzyme A (group I) whereas the other four strains produced both enzymes A and B (group II). The high susceptibility to the combination of amoxycillin and clavulanate observed in one subtype was explained by the absence of the cephalosporinase enzyme B. A simple disk diffusion test with this antibiotic combination was shown to be effective in the detection of enzyme B in Y. enterocolitica 4/O3.
Anti-Bacterial Agents↗