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Biomedical subjects

G Griffin

Publications and source records attributed to G Griffin.

At least 55 records · Page 3Linked to original sources

Myoclonic epilepsy in an HIV positive patient: neurophysiological findings.

An HIV-positive patient is described who presented with action myoclonus. Unusually, focal sinusoidal EEG burst complexes with a frequency of 40 and 55 Hz could be recorded over the sensorimotor cortex. Activity having a similar frequency was evoked in this area by posterior tibial nerve stimulation in the affected leg, and jerk-locked averaging showed that myoclonic jerks were preceded by similar cortical sinusoidal waves.

Acquired Immunodeficiency Syndrome↗

Evaluating the statewide dissemination of smoking prevention curricula: factors in teacher compliance.

As part of a larger study to evaluate the impact of a state-levied tax increase on tobacco products and the allocation of funds for smoking education, 81 schools were assigned randomly to one of four recommended smoking prevention programs for adolescents. The four programs differed in amount of program structure and extent of teacher training required. A one-session observation was made of 106 teachers in the 81 schools to assess the percentage of time allocated to recommended activities--those based on the social influences model. Data suggest an explicit curriculum with designed activities and face-to-face teacher training results in greater compliance to prescribed program components.

Adolescent↗

Small fenestra stapedotomy using a fiberoptic hand-held argon laser in obliterative otosclerosis.

Obliterative otosclerosis has been a challenge since the advent of stapes surgery. "Drill-out" procedures have had a generally poorer prognosis than conventional stapes surgery because of excessive bleeding, acoustic trauma from the burr, and reclosure of the oval window by otosclerosis. In this report, we describe our early experience using a hand-held fiberoptic argon laser for small fenestra stapedotomy in 10 cases of obliterative otosclerosis. Closure of the air-bone gap to within 10 dB was seen in 100% of the patients. There was no significant sensorineural hearing loss, vertigo, or facial weakness. Argon-laser stapedotomy using a hand-held fiberoptic system is a safe and effective alternative to drill-out stapedotomy in cases of obliterative otosclerosis.

Fenestration, Labyrinth↗

[Subcophosis and otosclerosis. Medical and surgical treatment].

The spiral ligament of the stria vascularis is nearly always damaged by otosclerotic foci when the patient is nearly totally deaf because of otosclerosis. Vascular drugs are to be prescribed in such a case, besides the Sodium Fluoride treatment. The Sodium Fluoride is, according to us, the best treatment to arrest the progression of the otosclerotic disease. Sodium fluoride will destroy the proteolytic enzymes damaging the inner ear membranes and the hair of the Corti hair cells.

Audiometry↗

[Gherini-Causse endo otoprobe and HGM argon laser. Value in the surgery of ear abnormalities].

Performing a stapedectomy in a slightly fixed otosclerotic footplate may induce an excessive motion of the labyrinthine fluids, damaging inner ear membranes and Corti hair cells fragilized by proteolytic enzymes. The fluid motion in the cochlear canal is quantic size only. The replacement of a slightly fixed footplate by an ideal compliance and impedance transmitting device, may allow the surgeon to get a tremendous improvement of hearing (as a Meniere disease). The Gherini-Causse multi-use endo-otoprobe combined with a HGM Argon Laser, if associated with a Skeeter Oto-tool drill, looks to be an efficient and safe solution to this otologic surgical challenge.

Argon↗

Effect of magnesium on cocaine-induced, catecholamine-mediated platelet and vascular response in term pregnant ewes.

Ten pregnant ewes were alternated in a study of the blocking effect of parenteral magnesium on the catecholamine response to cocaine. Indirect blood pressures were recorded at 1-minute intervals for 12 minutes before and after a bolus of 2 mg/kg of cocaine. Fetal heart rates were continuously recorded from skin electrodes. Platelet counts were performed before and 12 minutes after cocaine. Control ewes received lactated Ringer's solution, and test animals had 5 mg/kg of elemental magnesium in the form of MgSO4-7H2O in a rapid infusion. A semicrossover was also performed. Platelet counts fell precipitately in controls and rose after magnesium infusions. Fetal heart rates rose in controls at 5-minute intervals and were unchanged in magnesium-treated mothers. Because of disparity of the baseline mean arterial pressure, direct comparisons were not significant before and after cocaine. Alterations from the baseline were different in magnesium-treated versus control animals, with values in the latter rising by 28 +/- 10 mm Hg with lactated Ringer's solution plus cocaine and falling by 3 +/- 5 mm Hg with magnesium pretreatment. Values in test animals originally treated with magnesium rose 4 +/- 11 mm Hg for an overall significance of p less than 0.05. Low beginning serum magnesium levels were associated with ovine hypertension and reduced fetal weight and survival.

Animals↗

Growth after construction of the temporomandibular joint in children with hemifacial microsomia.

Free costochondral grafts have been used to construct the absent ascending ramus and condylar head of 22 children with hemifacial microsomia (HFM) who were less than 14 years of age. Evidence of continued growth was demonstrated in all patients. Growth was determined by measurement of cephalograms or by inference; if the patient grew extensively in height but his/her face remained symmetric, the graft was inferred to have grown. In two patients, considerable overgrowth occurred, displacing the chin to the opposite side and causing a class III malocclusion. Variations in age or type of adjunctive operations did not affect growth. There appears to be no single explanation for all findings. Because all of the grafts grew, early joint construction and correction of hemifacial microsomia are advocated.

Adolescent↗

A statewide approach to adolescent tobacco-use prevention: the Minnesota-Wisconsin Adolescent Tobacco-Use Research Project.

Adolescent smoking rates remain high and the use of smokeless tobacco is increasing, especially among males. Despite this continuing public health problem and the recent development of more effective prevention programs, few adolescents now participate in such programs at school. Recent legislation in Minnesota established guidelines for tobacco-use prevention programming and provides financial incentives to school districts to use more effective methods. The Minnesota-Wisconsin Adolescent Tobacco-Use Research Project has implemented an evaluation design that will provide data on the efficacy of this statewide approach to the prevention of tobacco use among adolescents. This article describes the current state of tobacco-use prevention programming in Minnesota schools, current efforts to improve on that record, and the research design set up to evaluate these strategies.

Adolescent↗

Simulated acidosis does not impair 1,25-dihydroxyvitamin D3 production by cultured kidney cells.

Cultured mouse kidney cells grown in serum-free medium were used to assess the metabolism of 25-hydroxyvitamin D3 in the presence of simulated metabolic acidosis. Kidney epithelial cells isolated from 4-6 week old mice were grown to confluence in a defined serum-free medium at pH 7.4. The confluent monolayers were incubated with tritiated 25-hydroxyvitamin D3 for 6 hours, the samples were extracted, and vitamin D metabolites were separated and quantitated by high pressure liquid chromatography (HPLC). The pH of the incubation medium was set at 6.9, 7.1, 7.4, or 7.7 by adjusting the bicarbonate concentration, using chloride as the balancing anion at constant Pco2. When pH was altered at the beginning of the 6 hour assay, production of 1,25-dihydroxyvitamin D3 was the same at each pH. More prolonged pH perturbation for a total of 30 hours likewise had no influence on 1,25-dihydroxyvitamin D3 production. These results confirm that intact mammalian kidney cells in serum-free culture possess an active 25-hydroxyvitamin D3-1-hydroxylase and that the activity of the enzyme is unaffected by pH over the range 6.8-7.7. In experiments where acidosis has been shown to alter 1,25-dihydroxyvitamin D3 production, the mechanism was probably indirect.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗

Assessing needs for youth health promotion.

Children and adolescents recently have become a group targeted for health promotion efforts. It is argued that early behavioral intervention will alter patterns of behavior that might place young people at increased risk for chronic diseases later in life. The Minnesota Heart Health Program is a longitudinal, community-based research and demonstration project to improve cardiovascular health in three north central communities. Reductions in cigarette smoking, improved eating and exercise patterns, and hypertension management are targeted objectives. To design educational interventions for children and adolescents in these areas as part of this program, a behavioral needs assessment was conducted in the communities prior to program implementation. This needs assessment focused on existing behavior patterns, skills related to the targeted behaviors, and environmental influences. This article describes that needs assessment, the results from two of the communities, differences due to gender and age of student, and the implications of the results for designing intervention activities for children and adolescents.

Adolescent↗

Role of hepatic arterial embolisation in the carcinoid syndrome.

Eighteen patients with severe symptoms of the carcinoid syndrome were assessed for hepatic embolisation. Four were too ill, and one had mild symptoms; thus 13 received a periembolisation regimen of cyproheptadine, fenclonine, aprotinin, methylprednisolone, tobramycin, flucloxacillin, and metronidazole. Embolisation was not performed in one patient with an occluded portal vein and was unsatisfactory in two others, in one because she was moribund and in the other because the hepatic artery had been ligated. Dramatic improvement in symptoms occurred in the nine patients in whom embolisation was successfully carried out, with abolition of flushing, severe abdominal pain, and wheeze and reduction in diarrhoea from 10.5 (SD 7.6) to 1.6 (0.9) stools/day. Urinary excretion of 5-hydroxyindole acetic acid fell from 1048 (716) to 289 (184) mumol/24 h (200 (137) to 55 (35) mg/24 h). Complications included one death from septicaemia, a hepatic abscess requiring surgical drainage, abdominal pain in three patients, pleural effusion in two, and transient encephalopathy in one. Relief of symptoms lasted for one to 24 months, and second embolisation in two patients produced further remissions of four to six months. Five patients died, one to 40 months after embolisation, in four cases because of metastases or heart failure. Hepatic embolisation is the treatment of choice for symptoms of the carcinoid syndrome resistant to medical treatment.

Adult↗

Identification and somatotopic organization of nuclei projecting via the dorsolateral funiculus in rats: a retrograde tracing study using HRP slow-release gels.

Horseradish peroxidase (HRP) in slow-release gel was unilaterally implanted in the transected dorsolateral funiculus (DLF) of either cervical, midthoracic, lumbar or sacral spinal cord levels of adult male rats. Cell mappings were made of all brain areas projecting through the DLF. Following cervical implants, dense labelling was observed within a band along the dorsolateral border of the inferior olive, locus coeruleus, the paralemniscal reticular formation, the mesencephalic central gray, the red nucleus and the paraventricular nucleus of the hypothalamus. The DLF projection from the central gray consisted of a rostrocaudal line of cells extending from the level of the mesen-/diencephalic junction to the rostral red nucleus. The somatotopic organization of labelled nuclei was assessed by comparing the pattern of filled cells following HRP implants at various cord levels. The potential role of these areas in pain modulation was discussed in light of their descending projections through the DLF of the spinal cord.

Afferent Pathways↗

Biofeedback regulation of temporal EEG alpha asymmetries.

Integrated EEG alpha was recorded from T3 and T4. Larger R alpha/L alpha ratios were defined as right asymmetry, relatively smaller ratios as left asymmetry. In different phases of the study, participants attempted to identify the presence of the EEG asymmetries and to produce the EEG asymmetries during auditory biofeedback, and were tested on hemisphere-specialized cognitive tasks while attempting to produce the EEG asymmetries. Experiential descriptions of the EEG asymmetries were obtained throughout using a set of bipolar scales. Some participants were able to identify the presence of the EEG asymmetries (p less than .05). As a group there was numerically small but significant (p less than .05) biofeedback control of the EEG asymmetries, but no improvement across sessions of training. There were marked individual differences in the ability to control the EEG asymmetries and in L alpha and R alpha during control. During baselines L alpha and R alpha were strongly positively correlated across time. Experiential descriptions were not consistent across participants. Effects of EEG asymmetries on performance of hemisphere-specialized tasks were demonstrated for one participant.

Adult↗

Acute effects of alcohol on evoked potentials in visual cortex and superior colliculus of the rat.

This study examined the effects of alcohol on visually evoked potentials recorded from the primary visual cortex (VC) and superior colliculus (SC) of chronically implanted rats. Animals were given intraperitoneal injections of saline, and of 0.15, 0.5, 1.0 and 1.5 g ethanol/kg body weight on separate days. Evoked potentials were recorded at 5, 20, 40, and 60 min following injection. There were differential effects of both alcohol and habituation on the early versus late VC components. The amplitudes of the late components decreased over time and were also depressed by both the 1.0 and 1.5g/kg doses of alcohol. Amplitudes of the early components increased over time and were unaffected by the 1.0g/kg alcohol dose. The 1.5g/kg dose depressed the early negative component but augmented the early positive component. In contrast to the amplitudes, the latencies of both early components were increased at both the l.0 and 1.5g/kg doses. However, the latency of the late positive component was increased at only the 1.5 g/kg dose, while the latency of the late negative component was unaffected by any alcohol dose. In the SC, the peak amplitude of the early positive complex was unaffected by either habituation or alcohol. However, both the amplitude and latency of a later negative component (latency of 52 msec) were affected by alcohol. The 1.0 and 1.5g/kg doses decreased peak amplitude, while the latency was increased at the highest dose. These effects of alcohol on the SC component were in directions opposite to those resulting from habituation.

Animals↗