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1.
Subst Use Misuse ; 56(11): 1707-1714, 2021.
Article in English | MEDLINE | ID: mdl-34253161

ABSTRACT

OBJECTIVE: Cigarette smoking is inversely associated with education, and despite this gradient effect, individuals with a General Educational Development (GED) diploma, obtained through a high school equivalency test, have the highest smoking prevalence. Considered the high school equivalency credential, it is unclear why individuals with a GED have a substantially higher smoking prevalence compared to high school graduates and dropouts. We conducted a qualitative study to understand life experiences, tobacco use patterns, and perceptions of tobacco among GED smokers and attitudes and behaviors around smoking cessation. METHODS: We recruited 40 GED smokers aged 18 to 35 years and conducted surveys and semi-structured individual interviews. Transcripts were independently coded, then coding differences were resolved and reviewed by a third team member. We independently determined themes within and between codes and met to determine final themes. RESULTS: GED recipients had many early life experiences and characteristics that made them highly vulnerable to tobacco dependence. With perceived high cognitive abilities, GED smokers were knowledgeable of many evidence-based smoking cessation strategies and were aware of health risks. Health risks and the financial burden of smoking were motivation to quit. The majority were uninterested or lacked confidence that nicotine replacement therapy, medications, counseling, or the quitline could help them quit. Nearly all were enthusiastic and confident that financial incentives had the potential to help them quit. CONCLUSIONS: Research is needed to determine whether financial incentives could improve smoking cessation outcomes in this unique population with an unequal burden of smoking.


Subject(s)
Smoking Cessation , Humans , Motivation , Smokers , Smoking , Tobacco Use Cessation Devices
2.
Drug Alcohol Depend ; 218: 108399, 2021 01 01.
Article in English | MEDLINE | ID: mdl-33250381

ABSTRACT

BACKGROUND: With research indicating some young audiences may desire to quit using JUUL, a high-nicotine e-cigarette, we sought to explore factors that may motivate them to quit. METHODS: This sequential, mixed methods study included a cross-sectional online survey of college students (n = 631) followed by in-person interviews (n = 51) with survey participants. Data were collected March-April 2019. The survey asked about intention to quit using JUUL. A latent class analysis (LCA) identified participant groups who would quit for various reasons. Participants were also asked 'Can you be too old to JUUL?' during the survey. During the interviews, participants were provided preliminary survey findings and asked about their perceptions of the data. Interview participants were also asked about their expectations for future use of JUUL. RESULTS: Four classes emerged from the LCA, indicating costs to self (i.e., harm to lungs/brain, price; 46.8%), financial costs (36.6%), all costs (e.g., social, monetary, health; 9.3%), and harm to self (7.3%) may have influenced our sample's decision to quit using JUUL. Interviewees affirmed desires to quit using JUUL, especially after leaving college. Only 27.19% of survey participants reported an age threshold for using JUUL (M = 31.8 years, SD = 10.0); however, several interviewees explained that although someone could not be too old to JUUL, it would be 'immature' or 'childish' for adults who were not trying to quit smoking to use JUUL socially. DISCUSSION: Comprehensive tobacco control strategies such as taxing e-cigarettes, marketing campaigns, and nicotine cessation programs are needed to help nicotine dependent young adults quit using high-nicotine e-cigarettes.


Subject(s)
Electronic Nicotine Delivery Systems/statistics & numerical data , Smoking Cessation/psychology , Adolescent , Adult , Cross-Sectional Studies , Female , Humans , Intention , Male , Marketing , Motivation , Nicotine , Smoking , Smoking Cessation/statistics & numerical data , Students , Surveys and Questionnaires , Tobacco Products/statistics & numerical data , Tobacco Use , Universities , Vaping , Young Adult
3.
Colloids Surf B Biointerfaces ; 106: 151-7, 2013 Jun 01.
Article in English | MEDLINE | ID: mdl-23434705

ABSTRACT

A novel rapid green one-step method is developed for the preparation of bio-silica coated with amorphous MnO2 nanoparticles by treating bio-silica with an acidic permanganate solution. The method developed has the advantage of selectively coating the surface of either one or both sides of the porous silica structure with a thin catalytic active amorphous MnO2 layer in a controlled way. The uncoated and MnO2 coated bio-silica are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The catalytic activity of amorphous MnO2-coated bio-silica is examined by degrading organic dye at ambient condition. The as-synthesized samples show highly efficient and rapid degradation of Rhodamine B. The simplicity and cost-effectiveness of the materials and method can be very useful for highly efficient degradation of organic pollutants for environmental remediation.


Subject(s)
Environmental Pollutants/chemistry , Manganese Compounds/chemistry , Organic Chemicals/chemistry , Oxides/chemistry , Silicon Dioxide/chemistry , Catalysis , Environmental Restoration and Remediation/methods , Metal Nanoparticles , Microscopy, Electron, Scanning , Microscopy, Electron, Transmission , X-Ray Diffraction
4.
Eye (Lond) ; 21(3): 353-61, 2007 Mar.
Article in English | MEDLINE | ID: mdl-16397620

ABSTRACT

PURPOSE: To investigate the relationship between visual acuity and foveal birefringence in patients with neovascular age-related macular degeneration. METHODS: In total, 40 patients with choroidal neovascularization underwent macular imaging with scanning laser polarimetry. Bowtie patterns, typically seen in birefringence images of the macula, were evaluated and classified into three categories: (1) regular bowtie present; (2) bowtie present, but disrupted; and (3) no bowtie present. The relation of the bowtie appearance to the best-corrected logMAR visual acuities was tested (ANOVA). RESULTS: Mean visual acuity was best for the group that had regular bowties (mean logMAR=0.34) and differed statistically significantly from the disrupted bowtie group and no bowtie group (P=0.01 and 0.0007). Ages for the three groups did not differ (P=0.31). CONCLUSIONS: Appearance of a regular bowtie indicates a substantially intact Henle fibre layer with the potential for good visual function, despite the presence of underlying pathology. Conversely, disruption or absence of a bowtie may indicate severe damage to the photoreceptors, consistent with the finding of poorer visual acuity.


Subject(s)
Choroidal Neovascularization/physiopathology , Fovea Centralis/physiopathology , Macular Degeneration/physiopathology , Visual Acuity/physiology , Aged , Birefringence , Choroidal Neovascularization/complications , Cohort Studies , Diagnostic Techniques, Ophthalmological , Female , Fluorescein Angiography/methods , Humans , Lasers , Macular Degeneration/complications , Male , Middle Aged
5.
Arch Otolaryngol Head Neck Surg ; 127(8): 991-6, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11493212

ABSTRACT

BACKGROUND: Xerostomia is a devastating complication of radiation therapy. Previous research has demonstrated that submandibular glands may be removed from the neck and transplanted using microvascular techniques, with good gland survival. However, microvascular transplantation and replantation has never been attempted on a composite tissue such as a salivary gland. OBJECTIVE: To evaluate the ability of a rabbit submandibular gland to undergo 2 successive microvascular transplantations. SUBJECTS AND DESIGN: Study rabbits underwent a midline neck incision with dissection of a submandibular gland to its arterial and venous pedicle. Microvascular techniques were then used to transplant the gland to the femoral system of the right groin. The incisions were reopened later under surgical conditions. The transferred gland was examined for survival and patency of its artery and vein. Healthy glands were dissected and transferred to a suitable artery and vein within the neck, where they were again reanastamosed using microvascular surgical techniques. After additional time, the gland was again examined for survival and pedicle patency, then removed and evaluated for histopathological evidence of survival. RESULTS: Surgical technique evolved during the course of this work to avoid encountered pitfalls. After refining the technique, we have determined that the rabbit submandibular gland is able to withstand successive microvascular transplantation and replantation with good likelihood of long-term survival, according to histopathological criteria. CONCLUSIONS: The rabbit submandibular gland is able to undergo microvascular transplantation and replantation with evidence of long-term survivability and preserved function. The body's natural response to surgery and tissue transplantation makes replantation a technical challenge; however, methods delineated herein alleviate many of the potential pitfalls. Extending these results to humans, patients who are to undergo radiation therapy could have a disease-free gland removed from the neck, transferred outside of the field of radiation, and then returned to the neck at the completion of radiation therapy. This may enable them to maintain salivary gland function and maintain oral cavity function and comfort.


Subject(s)
Submandibular Gland/transplantation , Transplantation, Heterotopic , Anastomosis, Surgical , Animals , Female , Graft Survival , Groin , Microsurgery , Neck , Rabbits , Reoperation , Submandibular Gland/blood supply , Vascular Surgical Procedures
6.
Arch Facial Plast Surg ; 3(3): 170-7, 2001.
Article in English | MEDLINE | ID: mdl-11497501

ABSTRACT

BACKGROUND: The temporoparietal fascial flap has proven to be a versatile flap for a broad spectrum of reconstructive problems in the head and neck. The temporoparietal fascial flap is a thin, pliable layer of richly vascularized tissue that may be transferred either pedicled or free and alone or as a carrier of subjacent bone or overlying skin and scalp. OBJECTIVE: To report our experience using a hair-bearing temporoparietal fascial flap for reconstruction in 6 male patients with extensive upper lip and scalp defects, including a discussion of the surgical anatomy and technique. METHODS: Temporoparietal fascial flaps with overlying scalp were used as pedicled and free flaps for the reconstruction of upper lip and scalp defects. RESULTS: All reconstructive results were satisfactory. Oral competence, measured by both speech and mastication performance, was achieved in patients with upper lip defects. Healthy scalp coverage was obtained in patients with local defects. The cosmetic appearance was satisfactory to all patients. CONCLUSIONS: Ideal reconstruction of large upper lip and scalp defects is achieved with local tissue that best mimics the normal face color, texture, and hair-bearing qualities. Hair-bearing temporoparietal fascial flaps possess these characteristics and are an excellent choice for the restoration of function and aesthetics.


Subject(s)
Lip/surgery , Scalp/surgery , Surgical Flaps , Adult , Aged , Alopecia/surgery , Carcinoma, Basal Cell/surgery , Carcinoma, Squamous Cell/surgery , Facial Neoplasms/surgery , Hair/transplantation , Head and Neck Neoplasms/surgery , Humans , Male , Melanoma/surgery , Middle Aged , Osteosarcoma/surgery
7.
Environ Toxicol Chem ; 20(5): 1031-6, 2001 May.
Article in English | MEDLINE | ID: mdl-11337865

ABSTRACT

Polycyclic aromatic hydrocarbons (PAHs) are important contaminants of world water resources, with effects on aquatic life. Metabolic responses to short-term acute toxicities of naphthalene, anthracene, and chrysene were investigated in the freshwater bivalve mollusk Elliptio complanata using differential scanning calorespirometry coupled with uptake and scanning electron microscopy. Comparing the uptakes of naphthalene, anthracene, and chrysene with that of inulin, which is known to occupy only extracellular space, showed that all compounds studied were taken up. The PAHs studied had diverse effects on the metabolic activity of E. complanata. Naphthalene and, to a lesser degree, chrysene caused stimulation of heat rates, possibly due to uncoupling of oxidative metabolism. Differential scanning calorespirometry coupled with studies of rates of oxygen consumption by the gill tissue exposed to the PAHs showed similar diverse patterns of respiratory rate stimulation and inhibition. Analysis of results of scanning electron microscopy suggested that irreversible damage to the gill tissue occurred in the presence of anthracene but not in the presence on naphthalene or chrysene. The batch calorespirometric method coupled with uptake and spectroscopy proved to be a useful technique to assess the toxicity of PAHs on the control of energy flux in gills of a freshwater bivalve mollusk.


Subject(s)
Mollusca/metabolism , Polycyclic Compounds/metabolism , Polycyclic Compounds/toxicity , Animals , Calorimetry, Differential Scanning , Microscopy, Electron, Scanning , Oxygen Consumption
8.
Environ Toxicol Chem ; 20(2): 309-16, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11351430

ABSTRACT

Polycyclic aromatic hydrocarbons (PAHs) and herbicides are important contaminants of world water systems with effects on aquatic organisms. The uptake of naphthalene, anthracene, and chrysene by gills of the bivalve mollusk Elliptio complanata was determined. Additionally, the effects of paraquat, atrazine, alachlor, 2,4-dichlorophenoxyacetic acid (2,4-D), and 2,4-dinitrophenol on the uptake of these compounds were also determined. The results indicate (1) the uptake of anthracene is approximately equivalent to that of chrysene and the uptake of either of these compounds is higher than that of naphthalene; (2) comparisons of uptakes with that of inulin, which occupies only extracellular space, show that all compounds studied are taken up; (3) the uptakes of naphthalene, anthracene, and chrysene are initially altered by the presence of herbicides such as paraquat, alachlor, 2,4-D, atrazine, and 2,4-dinitrophenol.


Subject(s)
Gills/metabolism , Polycyclic Compounds/pharmacokinetics , Animals , Herbicides/pharmacology , Mollusca
9.
Microsurgery ; 21(3): 96-101, 2001.
Article in English | MEDLINE | ID: mdl-11372069

ABSTRACT

This study hypothesized that introducing high numbers of Schwann cells in monolayers via a novel rolled graft architecture would promote robust nerve regeneration. The objective was to place adherent Schwann cells in artificial nerve grafts and to assess regeneration through the Schwann cell-laden grafts compared with that through acellular grafts and autografts. Schwann cells were isolated from neonatal Fisher rats. Small intestinal submucosa (SIS) was harvested from adult Fisher rats, cut into 7 mm x 8 cm pieces, and pinned out. Schwann cells were plated onto the strips, allowed to reach confluence, and subsequently rolled into a laminar structure and implanted across a 7-mm gap in the rat sciatic nerve (n = 12). Control animals received SIS conduits without Schwann cells (n = 11) or autograft repair (n = 12). At 10.5 weeks, functional regeneration through the Schwann cell-laden grafts, measured by both sciatic function index and extensor postural thrust testing, exceeded that through the cell-free grafts and approached that achieved through autografts. These results highlight the role of Schwann cells in nerve regeneration. Regenerative results approaching autograft levels in the Schwann cell-laden group suggest that this methodology may ultimately be useful in clinical nerve repair.


Subject(s)
Nerve Regeneration , Schwann Cells , Sciatic Nerve/physiopathology , Sciatic Nerve/surgery , Animals , Axons/physiology , Collagen , Rats , Schwann Cells/physiology
10.
Neurosurg Focus ; 10(3): E8, 2001 Mar 15.
Article in English | MEDLINE | ID: mdl-16734411

ABSTRACT

OBJECT: Clival chordomas are frequently midline lesions whose posterior growth may breach the dura and invaginate the brainstem. This precludes safe delivery of potentially curative high-dose fractionated proton radiotherapy. To avoid this problem, the authors performed pedicled rhinotomy to resect chordomas in 10 patients. METHODS: Pedicled rhinotomy is a midface transnasal route to the intercarotid sella and clivus from the tuberculum sellae to the mid-C-2 level. It involves a lateral rhinotomy incision, osteotomies of nasal bones and cartilage, lateral rotation of the nose, removal of the nasal septum and medial maxillary walls, opening of ethmoid and sphenoid sinuses, and dissection of nasopharynx and oropharynx to expose the clivus and craniovertebral junction. Tumors involving the sella, medial cavernous sinuses, middle and lower clivus, and C-1 arch and dens can be removed even if they traverse the dura. Closure involves dural repair, grafting of fat and split-thickness skin, rotation of a vascularized mucosal pedicle, and reattachment of nasal cartilage. Ten clival chordomas in adult patients were surgically removed via a pedicled rhinotomy approach. Seven patients had previously undergone a total of nine skull base procedures. In eight of the 10 patients, tumors compressing the brainstem were completely removed using this technique. One patient required an additional subtemporal resection of a suprasellar tumor before definitive radiotherapy could be undertaken. No patient sustained any new neurological deficit; in eight patients headache, diplopia, or hemiparesis improved. One patient developed postoperative cerebrospinal fluid leakage and meningitis that were successfully treated with antibiotic agents and shunt placement. CONCLUSIONS: Pedicled rhinotomy provides excellent shallow-field exposure of midline clival chordomas and permits relief of brainstem compression and the postoperative administration of potentially curative proton beam irradiation.


Subject(s)
Chordoma/surgery , Nasal Cavity/surgery , Skull Base Neoplasms/surgery , Adult , Chordoma/pathology , Cranial Fossa, Posterior , Dura Mater/pathology , Dura Mater/surgery , Female , Humans , Male , Middle Aged , Neoplasm Invasiveness , Retrospective Studies , Skull Base Neoplasms/pathology , Treatment Outcome
12.
Arch Facial Plast Surg ; 2(3): 196-201, 2000.
Article in English | MEDLINE | ID: mdl-10938143

ABSTRACT

OBJECTIVE: To evaluate the success of the temporoparietal fascial flap (TPFF) in the primary or secondary reconstruction of difficult orbital defects and to review the surgical techniques. DESIGN: Retrospective analysis. SETTING: Tertiary medical center. PATIENTS: Nine patients with diverse orbital cavity or periorbital soft tissue and bony defects due to trauma, benign or malignant neoplasms, and radiation treatment. INTERVENTIONS: Temporoparietal fascial flap anatomy and techniques of harvest and inset are reviewed in detail. Four cases are presented to illustrate possible variables in orbital reconstruction. Variables examined include the location of defects, the success of flap survival in orbital cavities after primary or secondary reconstruction, the effects of prior irradiation on flap survival, and the possibility of concurrent osteointegrated implant placement with TPFF reconstruction. MAIN OUTCOME MEASURES: Functional and aesthetic outcomes were determined by physical examination and preoperative and postoperative photographs. RESULTS: All patients had successful transfer of TPFF grafts without flap compromise. Temporoparietal fascial flap was a viable option for subtle orbital and malar contour defects. In chronically inflamed wounds such as with osteoradionecrosis and orbitoantral fistula, TPFF successfully restored vascularity, obliterated the defects, and enabled the placement of osteointegrated implants. The TPFF also supported the concurrent placement of a free calvarial bone graft. Finally, split-thickness skin grafted onto a pedicled TPFF showed 100% survival. CONCLUSIONS: The TPFF is one of the most reliable and versatile regional flaps in the head and neck for orbital reconstruction. This study presents the use of TPFF in a variety of orbital defects, from lateral bony rim defects to total exenteration. Timing of repair in this study spans from immediate reconstruction to reconstruction delayed more than 50 years after the initial injury. In all cases, reconstruction with TPFF resulted in improved bony and soft tissue contours, and incurred minimal morbidity.


Subject(s)
Facial Injuries/surgery , Orbital Neoplasms/surgery , Plastic Surgery Procedures , Soft Tissue Injuries/surgery , Surgical Flaps , Adult , Aged , Carcinoma, Basal Cell/surgery , Female , Hemangioma/surgery , Humans , Male , Orbital Implants , Retrospective Studies
13.
Tissue Eng ; 6(2): 119-27, 2000 Apr.
Article in English | MEDLINE | ID: mdl-10941207

ABSTRACT

Alternatives to autografts have long been sought for use in bridging neural gaps. Many entubulation materials have been studied, although with generally disappointing results in comparison with autografts. The purpose of this study was to design a more effective neural guidance conduit, to introduce Schwann cells into the conduit, and to determine regenerative capability through it in an in vivo model. A novel, fully biodegradable polymer conduit was designed and fabricated for use in peripheral nerve repair, which approximates the macro- and microarchitecture of native peripheral nerves. It comprised a series of longitudinally aligned channels, with diameters ranging from 60 to 550 microns. The lumenal surfaces promoted the adherence of Schwann cells, whose presence is known to play a key role in nerve regeneration. This unique channel architecture increased the surface area available for Schwann cell adherence up to five-fold over that available through a simple hollow conduit. The conduit was composed of a high-molecular-weight copolymer of lactic and glycolic acids (PLGA) (MW 130,000) in an 85:15 monomer ratio. A novel foam-processing technique, employing low-pressure injection molding, was used to create highly porous conduits (approximately 90% pore volume) with continuous longitudinal channels. Using this technique, conduits were constructed containing 1, 5, 16, 45, or more longitudinally aligned channels. Prior to cellular seeding of these conduits, the foams were prewet with 50% ethanol, flushed with physiologic saline, and coated with laminin solution (10 microg/mL). A Schwann cell suspension was dynamically introduced into these processed foams at a concentration of 5 X 10(5) cells/mL, using a simple bioreactor flow loop. In vivo regeneration studies were carried out in which cell-laden five-channel polymer conduits (individual channel ID 500 microm, total conduit OD 2.3 mm) were implanted across a 7-mm gap in the rat sciatic nerve (n = 4), and midgraft axonal regeneration compared with autografts (n = 6). At 6 weeks, axonal regeneration was observed in the midconduit region of all five channels in each experimental animal. The cross-sectional area comprising axons relative to the open conduit cross sectional area (mean 26.3%, SD 10. 1%) compared favorably with autografts (mean 23.8%, SD 3.6%). Our methodology can be used to create polymer foam conduits containing longitudinally aligned channels, to introduce Schwann cells into them, and to implant them into surgically created neural defects. These conduits provide an environment permissive to axonal regeneration. Furthermore, this polymer foam-processing method and unique channeled architecture allows the introduction of neurotrophic factors into the conduit in a controlled fashion. Deposition of different factors into distinct regions within the conduit may be possible to promote more precisely guided neural regeneration.


Subject(s)
Biocompatible Materials , Lactic Acid , Nerve Regeneration , Peripheral Nerves/physiology , Polyglycolic Acid , Polymers , Schwann Cells/cytology , Animals , Biomedical Engineering , Microscopy, Electron, Scanning , Nerve Regeneration/physiology , Peripheral Nerves/cytology , Peripheral Nerves/transplantation , Polylactic Acid-Polyglycolic Acid Copolymer , Rats , Rats, Inbred F344 , Schwann Cells/physiology , Schwann Cells/transplantation , Sciatic Nerve/cytology , Sciatic Nerve/physiology , Sciatic Nerve/transplantation , Transplantation, Autologous
14.
Head Neck ; 22(5): 463-8, 2000 Aug.
Article in English | MEDLINE | ID: mdl-10897105

ABSTRACT

BACKGROUND: Head and neck reconstructive surgeons involved in pharyngoesophageal reconstruction have several options available to repair the defect after partial or total laryngopharyngectomy. There is no uniform agreement among head and neck surgeons as to which of the most frequently used techniques offers the best results. METHODS: A retrospective study was performed on 20 consecutive patients who had undergone reconstruction of the hypopharynx and cervical esophagus using a radial forearm free flap with Montgomery salivary bypass tube at the Massachusetts Eye and Ear Infirmary in Boston, Massachusetts, and St. Louis University, Department of Otolaryngology-Head and Neck Surgery between 1992 and 1996. This reconstruction was used for primary reconstruction after total or partial laryngopharyngectomy with cervical esophagectomy, partial pharyngectomy sparing the larynx, and for reconstruction of the stenotic neopharynx after laryngectomy. RESULTS: The overall rate of pharyngocutaneous fistula was 20%, and the rate of postoperative stricture was 10%. Of patients reconstructed with this technique, 85% were able to resume oral alimentation, whereas 15% remained G-tube dependent. Of the 18 patients who did not have their larynges remain intact, 6 were able to develop useful tracheoesophageal speech. CONCLUSIONS: The results of this study show that the radial forearm fasciocutaneous free flap in combination with the Montgomery salivary bypass tube is extremely useful for reconstruction of partial and circumferential defects of the hypopharynx and cervical esophagus.


Subject(s)
Esophagectomy/rehabilitation , Fascia/transplantation , Intubation/instrumentation , Pharyngectomy/rehabilitation , Skin Transplantation , Surgical Flaps , Adult , Aged , Constriction, Pathologic/etiology , Cutaneous Fistula/etiology , Eating , Enteral Nutrition , Female , Fistula/etiology , Follow-Up Studies , Forearm , Gastrostomy , Humans , Hypopharynx/surgery , Laryngectomy/rehabilitation , Male , Middle Aged , Pharyngeal Diseases/etiology , Radial Artery , Retrospective Studies , Skin Transplantation/adverse effects , Skin Transplantation/methods , Speech, Esophageal , Surgical Flaps/adverse effects
15.
J Otolaryngol ; 29(1): 40-6, 2000 Feb.
Article in English | MEDLINE | ID: mdl-10709171

ABSTRACT

OBJECTIVE: To study the concept of facial muscle reinnervation from the trigeminal pathway following facial nerve paralysis. DESIGN AND METHODS: We studied this phenomenon in an animal model using the neuronal marker, horseradish peroxidase (HRP). The temporalis transposition procedure was performed at varying intervals post facial nerve transection. To evaluate the trigeminal-facial reinnervation process and its timing, the zygomaticus major muscle was injected with HRP at varied periods after temporalis transposition, and histologic sections of the brainstem nuclei were examined for the final location of the HRP. RESULTS: The presence of HRP in the trigeminal nucleus provided evidence of trigeminal-facial neurotization in those animals that underwent temporalis transposition up to 2 months following facial denervation and in which the HRP injection was performed 4 months after temporalis transposition. CONCLUSIONS: The findings of our pilot study are strongly supportive of the trigeminal-facial neurotization hypothesis in those animals that underwent temporalis transposition up to 2 months post facial denervation and in which 4 months were allowed thereafter for adequate neurite ingrowth and neurotization to occur. This suggests that the neurotrophic signals are greatest up to 2 months post denervation and denotes the optimal time for performance of reconstructive procedures. Future studies with a larger number of animals in each group will be necessary to ensure more potent statistical significance and to augment our experimental evidence that trigeminal-facial crossover does occur and can be used as an adjunctive concept to maximize early rehabilitation of the paralyzed face.


Subject(s)
Facial Muscles/innervation , Nerve Transfer , Surgical Flaps , Temporal Muscle/transplantation , Trigeminal Nerve/surgery , Animals , Biomarkers/analysis , Disease Models, Animal , Facial Muscles/surgery , Facial Nerve/pathology , Facial Paralysis/surgery , Guinea Pigs , Horseradish Peroxidase/analysis , Male , Neural Pathways/pathology , Neurites/ultrastructure , Pilot Projects , Temporal Muscle/innervation , Trigeminal Nerve/pathology , Trigeminal Nuclei/pathology
17.
Laryngoscope ; 109(9): 1412-6, 1999 Sep.
Article in English | MEDLINE | ID: mdl-10499046

ABSTRACT

OBJECTIVE/HYPOTHESIS: A wide variety of substances have been shown to promote neuritic extension after nerve injury. An obstacle to achieving the maximal benefit from these substances has been the difficulty in effectively delivering the substances over a protracted time course that promotes maximal, directed growth. In this study the delivery of a growth-promoting substance through a biodegradable conduit, using materials originally designed for drug delivery applications, was hypothesized to promote more robust neural regeneration than through conduits lacking the substance. The objectives of this study were to create a growth factor-loaded biodegradable nerve guidance conduit, and to assess in vivo nerve regeneration through the conduit compared with that through conduits lacking the substance. MATERIALS/METHODS: Inosine, a purine analogue thought to promote axonal extension following neural injury, was loaded into cylindrical polymer foams composed of a polylactide-co-glycolide copolymer. First, in vitro extravasation of inosine was measured over a several week period using spectrophotometry. Second, the foams were fashioned into single-channel cylindrical nerve guidance conduits via a novel, low-pressure injection molding technique. The conduits were then used to bridge 7-mm defects in the rat sciatic nerve (n = 8). Control conduits lacking inosine were implanted into another set of animals as controls (n = 12). RESULTS: In vitro spectrophotometric measurements indicated appreciable leaching of inosine from the loaded foams over a period of at least 9 weeks. In the in vivo model, after 10 weeks, a higher percentage cross sectional area composed of neural tissue existed through the inosine-loaded conduits compared with controls (mean 44%, SD 7.5% vs. 36%, SD 8.6%, respectively). A difference was also found in mean fiber diameter between the two groups, with the inosine-loaded tubes showing a statistically significantly larger diameter than controls (P < .05). CONCLUSIONS: A nerve regeneration conduit was successfully created that delivers growth promoting substances over a protracted time course. In an in vivo model, the presence of inosine, a purine analogue, yielded neural regeneration whose histological features suggest possible superior long-term motor function.


Subject(s)
Absorbable Implants , Inosine/therapeutic use , Lactic Acid , Nerve Growth Factors/therapeutic use , Nerve Regeneration/drug effects , Polyglycolic Acid , Polymers , Sciatic Nerve/physiology , Animals , Inosine/administration & dosage , Male , Nerve Growth Factors/administration & dosage , Polylactic Acid-Polyglycolic Acid Copolymer , Rats , Rats, Inbred F344 , Sciatic Nerve/surgery
19.
J Neurosci ; 19(2): 674-83, 1999 Jan 15.
Article in English | MEDLINE | ID: mdl-9880588

ABSTRACT

Several protein kinases are known to phosphorylate Ser/Thr residues of certain GABAA receptor subunits. Yet, the effect of phosphorylation on GABAA receptor function in neurons remains controversial, and the functional consequences of phosphorylating synaptic GABAA receptors of adult CNS neurons are poorly understood. We used whole-cell patch-clamp recordings of GABAA receptor-mediated miniature IPSCs (mIPSCs) in CA1 pyramidal neurons and dentate gyrus granule cells (GCs) of adult rat hippocampal slices to determine the effects of cAMP-dependent protein kinase (PKA) and Ca2+/phospholipid-dependent protein kinase (PKC) activation on the function of synaptic GABAA receptors. The mIPSCs recorded in CA1 pyramidal cells and in GCs were differentially affected by PKA and PKC. In pyramidal cells, PKA reduced mIPSC amplitudes and enhanced the fraction of events decaying with a double exponential, whereas PKC was without effect. In contrast, in GCs PKA was ineffective, but PKC increased the peak amplitude of mIPSCs and also favored double exponential decays. Intracellular perfusion of the phosphatase inhibitor microcystin revealed that synaptic GABAA receptors of pyramidal cells, but not those of GCs, are continually phosphorylated by PKA and conversely, dephosphorylated, most likely by phosphatase 1 or 2A. This differential, brain region-specific phosphorylation of GABAA receptors may produce a wide dynamic range of inhibitory synaptic strength in these two regions of the hippocampal formation.


Subject(s)
Cyclic AMP-Dependent Protein Kinases/metabolism , Hippocampus/enzymology , Neurons/enzymology , Protein Kinase C/metabolism , Receptors, GABA-A/physiology , Synapses/metabolism , Animals , Dentate Gyrus/cytology , Dentate Gyrus/physiology , Electric Stimulation , Enzyme Inhibitors/pharmacology , Evoked Potentials/physiology , Hippocampus/cytology , Hippocampus/ultrastructure , In Vitro Techniques , Intracellular Fluid/enzymology , Microcystins , Neurons/ultrastructure , Patch-Clamp Techniques , Peptides, Cyclic/pharmacology , Phosphorylation , Pyramidal Cells/enzymology , Rats , Rats, Wistar , Receptors, GABA-A/metabolism , Synapses/enzymology
20.
J Peripher Nerv Syst ; 4(3-4): 258-64, 1999.
Article in English | MEDLINE | ID: mdl-10642093

ABSTRACT

Assessment of functional recovery following any peripheral nerve manipulation is critical. While quantitative neurobehavioral testing has been developed in the anesthesia literature for the assessment of neural function, the surgical literature relies mainly on walking track analysis for evaluation of motor recovery. The latter method is both cumbersome to perform and difficult to quantify. We compared standard walking track analysis with the quantitative neurobehavioral tests recently developed for anesthetic testing. We found a close correlation between the recovery predicted by walking track analysis and that suggested by neurobehavioral testing. In addition, the neurobehavioral test battery offered information regarding the rate of return of pure motor function, complex integrated function, proprioceptive function, and sensation. The tests are easier to perform and less susceptible to interpretative error. Neurobehavioral testing may be an effective substitute for walking track analysis in the assessment of functional recovery following manipulation of the rat sciatic nerve.


Subject(s)
Locomotion/physiology , Motor Activity , Pain/physiopathology , Proprioception/physiology , Sciatic Nerve/injuries , Sciatic Nerve/physiopathology , Animals , Gait/physiology , Hindlimb , Muscle, Skeletal/innervation , Posture , Rats , Rats, Inbred F344 , Sciatic Nerve/physiology , Time Factors , Walking
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