Can I replace my body?
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Cloning, Organism↗
Biomedical subjects
A Park
Publications and source records attributed to A Park.
Postparotidectomy fistula: a different treatment for an old problem.
There is little consensus on the optimal management of postparotidectomy salivary fistulas. Timely treatment is important since fistulas may result in wound dehiscence and infection. Management options include pressure dressings, total parotidectomy, tympanic neurectomy, graft interpositioning, surgical closure of the tract, radiation therapy, and pharmacotherapy. Unfortunately, many therapies require weeks to months for resolution and possess additional risks. The affected patient often suffers social embarrassment from the drainage. Through our work with neurologically impaired children with sialorrhea, we have had success with using glycopyrrolate, an anticholinergic frequently used to decrease salivary secretions. We present a case of a patient with a postparotidectomy fistula which was successfully treated with glycopyrrolate and pressure dressings. The rationale and potential use of glycopyrrolate for the treatment of a salivary fistula are the focus of this presentation.
Adenoma, Pleomorphic↗
Laparoscopic vs open splenectomy.
HYPOTHESIS: Laparoscopic splenectomy (LS) provides health benefits to patients compared with open splenectomy (OS) in terms of perioperative morbidity, complications, and patient recuperation. DESIGN: Prospective operative and outcome data of LS patients were compared with those of OS patients (historical controls). SETTING: Data were gathered, and patients were evaluated and treated at 2 McMaster University teaching hospitals in Hamilton, Ontario, and at the University of Kentucky Chandler Medical Center, Lexington, also a teaching hospital. PATIENTS: From January 1, 1994, through October 31, 1998, a total of 210 patients were studied. Of them, 147 patients from 3 university teaching hospitals underwent LS. These patients were matched with 63 OS patients according to age, sex, spleen weight, indication for splenectomy, and preoperative morbidity score. INTERVENTIONS: A total of 147 patients evaluated for elective splenectomy underwent LS. MAIN OUTCOME MEASURES: Spleen weight, operative time, intraoperative blood loss, postoperative hospital stay, perioperative complications, and cost. RESULTS: No significant difference in mean spleen weight was found between groups. Mean operative time was significantly longer for LS, but intraoperative blood loss was significantly lower. Mean postoperative hospital stay was significantly lower and perioperative complications significantly fewer for LS patients. Mean cost for LS with no complications was slightly lower than for OS. CONCLUSIONS: Compared with OS, the lateral approach to LS takes longer to perform but results in reduced blood loss, shorter postoperative stay, and fewer complications. Mean weighted cost of LS is lower than OS at the study institutions. A prospective, randomized, controlled trial comparing these techniques is planned.
Adolescent↗
Laparoscopic pancreatic surgery.
BACKGROUND: Potential applications for laparoscopic surgery in pancreatic disease include (1) staging of pancreatic malignancies; (2) palliation of pancreatic malignancies; (3) pancreatic resections for benign and malignant disease; and (4) pancreatic drainage procedures. METHODS: A review of the literature is presented. In addition, original data on a series of 5 laparoscopic pancreatic distal resections and 10 laparoscopic cystogastrostomies are presented. RESULTS AND CONCLUSIONS: Laparoscopy may have a role in the staging of patients with pancreatic malignancies; however, with high-quality preoperative imaging, the percentage of patients who will benefit from laparoscopy may be as low as 5%. For palliation, both cholecystoenterostomy and choledochoenterostomy can be performed laparoscopically. The former is technically straightforward but has a higher failure rate; the latter is technically difficult and currently not suitable for widespread adoption. Laparoscopic gastroenterostomy is a straightforward means of palliating gastrointestinal obstruction. Patients appear to benefit from laparoscopic distal pancreatic resection but not from laparoscopic pancreaticoduodenectomy. Patients appear to benefit from laparoscopic pseudocyst decompression.
Humans↗
Handedness effects on playing a reversed or normal keyboard.
A group of left-handers, approaching the piano for the first time, showed better performance in playing a reversed keyboard (where the pitch decreased from left to right) than a normal keyboard. By testing a separate group of "experienced" left-handers, it was also found that this observed preference that naive left-handers had for the reversed keyboard can disappear with a few years of practice on a normal keyboard. The initial preference for the reversed keyboard shown by left-handers appeared to be specific for this handedness group, as groups of right-handers, regardless of their level of experience with the piano, performed better with the regular keyboard. Finally, based on these results it was hypothesised that left-handers would encounter considerable frustration in learning the "right-handed" piano. However, an informal demographic study of piano students enrolling at a school of music did not reveal a substantially low prevalence of left-handed pianists.
Journal Article↗
Nicotine Increases Spatiotemporal Complexity of Ventricular Fibrillation Wavefront on the Epicardial Border Zone of Healed Canine Infarcts.
BACKGROUND: The influence of a pharmacologic agent on wavefront dynamics during ventricular fibrillation (VF) in a setting of remodeled and healed myocardial infarction (MI) remains poor explored. We hypothesized that nicotine, by virtue of its complex direct and indirect cardiovascular effects, increases wavefront complexity during VF. Specifically, we sought to determine whether nicotine increases the number and complexity (approximate entropy) of wavelets during stage II VF in hearts with healed MI. METHODS AND RESULTS: The left anterior descending coronary artery was permanently occluded in five mongrel dogs and wavefront dynamics during VF studied 5 to 6 weeks after occlusion in the open-chest anesthetized state. VF was induced by rapid pacing and the activation pattern mapped on the surviving epicardial border zone (EBZ) of the left ventricle with a plaque (3.2 x 3.8 cm) having 477 bipolar electrodes 1.6 mm apart. VF was mapped before and 20 minutes after 5 µg/kg/min nicotine infusion. Nicotine with a mean arterial plasma concentration of 127 +/- 76 ng/mL (range 57 to 240 ng/mL) significantly (P <.01) increased the number of wavelents from 3.8 +/- 0.4 to 5 +/- 0.41. The increased number of wavelets was caused by an increase (P <.01) in the spontaneous breakup of wavefronts from 4.1 +/- 0.9 times/s to 6.9 +/- 1.1 times/s. Wavebreak over the EBZ was functional in nature as no breakup occurred during normal sinus rhythm. Approximate entropy, a measure of complexity, significantly (P <.01) increased after nicotine administration from 0.23 +/- 0.02 to 0.28 +/- 0.01. CONCLUSIONS: Nicotine increases the number of wavelets and their complexity during VF by promoting spontaneous wavebreak over the EBZ of healed MI.
Journal Article↗
Acute thermal injury to the canine jejunal free flap: electrocautery versus ultrasonic dissection.
Electrocautery-induced thermal injury contributes to morbidity and mortality after laparoscopic surgery. Ultrasonic dissection is an alternative technique that may produce less thermal injury. We compared the amount of acute thermal injury caused to jejunal free flaps isolated with laparoscopic electrosurgical instruments with that caused by ultrasonic dissection (laparoscopic coagulating shears). Canine jejunal free flaps were isolated by electrocautery or laparosonic coagulating shears and remained viable on a vascular pedicle. After a period of ischemia and reperfusion, the flaps were resected to simulate harvesting and reimplantation. Thermal injury was observed at the site of dissection and was graded histologically. At the margin of the jejunal free flaps, the laparosonic coagulating shears produced less thermal injury (score, 2.2 at level 3) than the electrocautery grasping forceps (score, 3.7 at 35 W and 4.1 at 70 W). The laparosconic coagulating shears produced less thermal injury to a jejunal free flap than did electrocautery. Ultrasonic dissection is an alternative to the complications produced by electrocautery during laparoscopic dissection.
Acute Disease↗
A week in the life of a hospital.
The same urgency and intellect that America's teaching hospitals apply to saving lives is now also going into saving the institutions themselves. All across the country, academic medical centers are trying to figure out how to marry progress with profits. At the Duke University Medical Center, TIME visits the front line in the war between money and medicine.
Budgets↗
Causes of death of wild birds of the family Fringillidae in Britain.
The provision of supplementary food for wild birds in gardens during the winter months is common in the UK, but it is possible that it may precipitate infectious diseases in the birds. This paper describes the results of postmortem examinations of 116 wild finches carried out over a period of four years. The two commonest causes of death in areas where high mortality had been reported were infections with the bacteria Salmonella typhimurium DT40 and Escherichia coli O86. Coccidia of the genera Atoxoplasma or Isospora were found in several of the birds but were considered to be incidental. Megabacteria were also identified in some of the birds, for the first time in flocks of wild birds in the UK, but they were not considered to be significant.
Animals↗
First AIDS vaccine: better than nothing.
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AIDS Vaccines↗
Laparoscopic splenic cystectomy: a case report.
Congenital epidermoid splenic cysts are very rare. They are known to become symptomatic as a consequence of enlargement, hemorrhage, rupture, or infection. Recent options in the treatment of splenic cysts have included percutaneous drainage, partial splenectomy, or open splenic cystectomy. The authors present the first report of a pediatric patient with a large epidermoid cyst of the spleen treated by laparoscopic partial cyst excision and omental packing. Follow-up at 1 year confirms no recurrence. Laparoscopy provides a minimal access method of obtaining pathological confirmation of diagnosis, reduction of cyst complications, and a short hospital stay, while preserving splenic function.
Adolescent↗
Lipomas of the head and neck in children.
Head and neck lipomas in the pediatric population are rarely described in the literature. Two patients who presented to the Hospital for Sick Children with rapidly enlarging head and neck lipomas are presented. Radiographic imaging, including CT and MRI, as well as fine needle aspiration implicated a lipoma as the probable diagnosis. Both patients were treated by surgical excision. The clinical behavior, diagnostic work-up and treatment of these rare lesions are the focus of this study.
Biopsy, Needle↗
A human HP1 pseudogene maps to chromosome 11p14.
The chromo multigene superfamily encodes numerous proteins involved in chromatin structure or organization. The prototypical member of this superfamily is HP1 of Drosophila melanogaster. We now present the sequence of a human HP1Hs gamma pseudogene and assign it to chromosome 11p14 by radiation hybrid mapping. The coding regions of at least three other human genes for HP1 orthologues and another pseudogene are very similar in sequence. These results demonstrate that HP1-type sequences have been duplicated multiple times in the mammalian genome.
Base Sequence↗
Laparoscopic and open incisional hernia repair: a comparison study.
BACKGROUND: Techniques for performing laparoscopic incisional hernia repair have been described and some advantages over conventional open repair reported. However, most reported series of laparoscopic incisional hernia procedures are small, and only one has included a comparison with open repairs. METHODS: From December 1993 to January 1998, we prospectively collected operative and outcome data on 56 consecutive laparoscopic prosthetic repairs of large incisional hernias. The data were compared with those from a retrospective view of 49 open incisional hernia repairs done in January 1991 to December 1993. RESULTS: The open and laparoscopic repair groups were comparable in patient age, sex, preoperative American Society of Anesthesiologists score, hernia size, and history of previous repair. Operative time was significantly longer in the laparoscopic group; duration of hospitalization and number of perioperative complications were significantly greater in the open group. CONCLUSIONS: In this series, laparoscopic repair of incisional hernias took longer to perform than open repair but was associated with fewer perioperative complications and a shorter hospital stay.
Abdomen↗
Integration of surface modification and 3D fabrication techniques to prepare patterned poly(L-lactide) substrates allowing regionally selective cell adhesion.
Regeneration of organizationally complex tissue requires regulation of spatial distributions of particular cell types in three dimensions. In this paper we demonstrate an integration of polymer processing and selective polymer surface modification using methods suitable for construction of three-dimensional polymer scaffolds which may aid such cell organization. Specifically, the surfaces of degradable polyesters were modified with poly(ethylene-oxide) (PEO)-poly(propylene-oxide) (PPO) copolymers using a process compatible with a solid free-form fabrication technique, the 3DP printing process. We demonstrate inhibition of cell (hepatocyte and fibroblast) adhesion to regions of two-dimensional poly(lactide) (PLA) substrates modified with PEO-PPO-PEO copolymers. We further show that PEO-PPO-PEO-modified surfaces which are not adhesive for hepatocytes or fibroblasts can be made selectively adhesive for hepatocytes by covalent linkage of a carbohydrate ligand specific for the hepatocyte asialoglycoprotein receptor to the PEO chain ends. Our approach may be generally useful for creating regionally selective, microarchitectured scaffolds fabricated from biodegradable polymers, for spatial organization of diverse cell types.
3T3 Cells↗
Clinical relevance of in vitro propagation of activated lymphocytes from endomyocardial biopsy samples of pediatric heart transplant recipients.
In vivo activated T-lymphocytes can be cultured from endomyocardial biopsy samples of human cardiac allografts, sometimes even in the absence of histological rejection. We investigated the clinical relevance of this "lymphocyte growth assay" in pediatric heart transplant recipients. Specifically, we wished to determine if: (i) positive lymphocyte growth from EMB samples in the absence of significant rejection identifies a patient as being at increased risk for the development of acute rejection; (ii) withdrawal or major dose reduction of corticosteroids in the presence of lymphocyte growth results in high risk of rebound rejection; and (iii) presence of lymphocyte growth during acute rejection helps predict the response to treatment. Cultures were performed on 789 consecutive EMB samples from 65 pediatric heart transplant recipients in media containing 30 U/ml of recombinant IL-2. T-lymphocytes were cultured from 16% of EMB samples with low grade rejection (grade 0-1b) and from 34% of EMB samples with grade 2-4 rejection. EMB samples obtained early post-transplant (<180 days) were significantly more likely to yield positive lymphocyte growth compared to biopsies obtained late for any given rejection grade. Lymphocyte growth was comparable between patients managed with cyclosporine or tacrolimus based immunosuppression. For 227 EMB samples without rejection, a subsequent EMB sample was obtained within 12 weeks. Lymphocyte cultures were positive in 47 of these 227 EMB samples (21%), and in 19 out of 47 (40%) cases acute rejection (grade 2-4) was present on the follow-up EMB sample. By contrast, of 180 biopsies without growth, only 29 (16%) showed rejection at the next EMB (p<0.0001). When a follow-up biopsy was performed within 12 weeks of corticosteroid withdrawal, "rebound rejection" was observed in 3 out of 10 (30%) cases where the previous EMB sample yielded positive lymphocyte growth and in 4 out of 38 (11%) cases when it did not (p=0.29). The presence of lymphocyte growth in association with rejection was also predictive of whether rejection would resolve following high dose intravenous corticosteroid therapy (persistent rejection in 33 out of 50 (66%) cases with positive growth, versus 25 out of 80 (31%) cases without growth (p<0.0001)). Thus, positive lymphocyte growth is strongly associated with higher grade of rejection and earlier time from transplantation. Lymphocyte growth in the absence of rejection indicates high risk for rejection within the next 12 weeks. Growth in association with acute rejection indicates high probability of persistence of rejection following treatment with high dose corticosteroids.
Adolescent↗
Laparoscopic resection of an intra-abdominal cystic mass: a cystic mesothelioma.
The clinical features of a patient with an intra-abdominal cystic mass do not lead to a specific diagnosis. Aspiration is usually ineffective because the mass recurs and cytologic investigation is often non-diagnostic. Conservative management is unsuccessful because symptoms often persist. Surgical management of cystic masses is required for definitive management and pathologic diagnosis. A laparoscopic approach to the diagnosis and treatment can provide essential anatomic information and a complete resection with minimal morbidity. A laparoscopic technique using 3 trocars and maintaining the integrity of the mass allows complete excision and removal of large intra-abdominal cystic masses as reported in a 43-year-old patient with a large intra-abdominal cystic mass identified as a benign cystic mesothelioma.
Adult↗
New generation dopaminergic agents. 1. Discovery of a novel scaffold which embraces the D2 agonist pharmacophore. Structure-activity relationships of a series of 2-(aminomethyl)chromans.
A series of 2-(aminomethyl)chromans (2-AMCs) was synthesized and evaluated for their affinity and selectivity for both the high- and low-affinity agonist states (D2High and D2Low, respectively) of the dopamine (DA) D2 receptor. The 7-hydroxy-2-(aminomethyl)chroman moiety was observed to be the primary D2 agonist pharmacophore. The 2-methylchroman moiety was discovered to be an entirely novel scaffold which could be used to access the D2 agonist pharmacophore. Attaching various simple alkyl and arylalkyl side chains to the 7-hydroxy 2-AMC nucleus had significant effects on selectivity for the D2High receptor vs the 5HT1A and alpha 1 receptors. A novel DA partial agonist, (R)-(-)-2-(benzylamino)methyl)chroman-7-ol [R-(-)-35c], was identified as having the highest affinity and best selectivity for the D2High receptor vs the alpha 1 and 5HT1A receptors. Several regions of the 2-AMC nucleus were modified and recognized as potential sites to modulate the level of intrinsic activity. The global minimum conformer of the 7-hydroxy-2-AMC moiety was identified as fulfilling the McDermed model D2 agonist pharmacophoric criteria and was proposed as the D2 receptor-bound conformation. Structure-activity relationships gained from these studies have aided in the synthesis of D2 partial agonists of varying intrinsic activity levels. These agents should be of therapeutic value in treating disorders resulting from hypo- and hyperdopaminergic activity, without the side effects associated with complete D2 agonism or antagonism.
Animals↗