Magnetospheric Multiscale Observations of the Electron Diffusion Region of Large Guide Field Magnetic Reconnection.

We report observations from the Magnetospheric Multiscale (MMS) satellites of a large guide field magnetic reconnection event. The observations suggest that two of the four MMS spacecraft sampled the electron diffusion region, whereas the other two spacecraft detected the exhaust jet from the event. The guide magnetic field amplitude is approximately 4 times that of the reconnecting field. The event is accompanied by a significant parallel electric field (E_{∥}) that is larger than predicted by simulations. The high-speed (∼300 km/s) crossing of the electron diffusion region limited the data set to one complete electron distribution inside of the electron diffusion region, which shows significant parallel heating. The data suggest that E_{∥} is balanced by a combination of electron inertia and a parallel gradient of the gyrotropic electron pressure.

Magnetospheric Multiscale Satellites Observations of Parallel Electric Fields Associated with Magnetic Reconnection.

We report observations from the Magnetospheric Multiscale satellites of parallel electric fields (E_{∥}) associated with magnetic reconnection in the subsolar region of the Earth's magnetopause. E_{∥} events near the electron diffusion region have amplitudes on the order of 100 mV/m, which are significantly larger than those predicted for an antiparallel reconnection electric field. This Letter addresses specific types of E_{∥} events, which appear as large-amplitude, near unipolar spikes that are associated with tangled, reconnected magnetic fields. These E_{∥} events are primarily in or near a current layer near the separatrix and are interpreted to be double layers that may be responsible for secondary reconnection in tangled magnetic fields or flux ropes. These results are telling of the three-dimensional nature of magnetopause reconnection and indicate that magnetopause reconnection may be often patchy and/or drive turbulence along the separatrix that results in flux ropes and/or tangled magnetic fields.

Evaluation of ozonated olive oil with or without adjunctive application of calcium sodium phosphosilicate on post-surgical root dentin hypersensitivity: a randomized, double-blinded, controlled, clinical trial.

AIM: This study was conducted to evaluate the efficacy of ozonated olive oil with or without adjunctive application of mineral wash containing calcium sodium phosphosilicate on the reversal of post-surgical root dentin hypersensitivity. METHODS: A double-blinded, randomized controlled clinical trial was conducted on 51 participants with root dentin hypersensitivity (RDH). Participants were randomLy assigned to 4 groups: Group A, ozonated olive oil (OZO): Group B, ozonated olive oil and mineral wash: Group C, placebo olive oil (PPO) and mineral wash: Group D, placebo olive oil only. Active treatment was carried out in-clinic and followed by at-home care with a remineralising paste. The response to various pain stimuli was periodically assessed with a visual analogue scale. Additionally, scanning electron microscopic study assessed the dentinal tubule occlusion and change in tubular surface area after treatment. RESULTS: The group B participants showed a significant decrease in tooth level and global sensitivity over the period (P<0.001). Moreover, the intergroup comparison also revealed a significant result (P<0.001). Similarly, participants of group C also showed a significant reduction in sensitivity over the period (P<0.001). Whereas, no significant (P>0.05) difference was detected between group A and group D for tooth level and global sensitivity analysis. The SEM study result showed a significantly (P<0.001) enhanced tubule occlusion and decreased tubular surface area in group B specimens compared to other group specimens. CONCLUSION: OZO, as a mono-therapy is not efficient in reducing post-surgical RDH. However, the adjunctive application of mineral wash containing calcium sodium phosphosilicate has positive impact on the reversal of post-surgical root dentin hypersensitivity.

Effect of subgingival application of topical ozonated olive oil in the treatment of chronic periodontitis: a randomized, controlled, double blind, clinical and microbiological study.

AIM: The aim of this paper was to evaluate the efficacy of ozonated olive oil as a monotherapy and an adjunct to scaling and root planing in the treatment of chronic periodontitis METHODS: A split mouth, double-blinded, randomized controlled clinical trial was conducted on 20 subjects diagnosed with chronic periodontitis. Quadrants of each subject were randomly assigned to four groups and treated accordingly: Group A, scaling and root planing (SRP): Group B, topical ozonated olive oil (OZO) as an adjunct to scaling and root planing: Group C, topical ozonated olive oil as a monotherapy and: Group D, topical chlorhexidine gel as a monotherapy. The quadrants were analyzed clinically by plaque index, gingival index, sulcus bleeding index, probing pocket depth, and clinical attachment level at baseline, 2, 4, 6 and 8 weeks of time intervals. The subjects were also analyzed for perceived pain, discomfort or tooth hypersensitivity (quadrant wise) on a Visual Analogue Scale (VAS). Additionally, subgingival plaque samples were collected from the two predetermined sites of each quadrant at baseline, 4 and 8 weeks for the analysis of total bacterial counts (TBCs) and the detection of frequency of eight putative periodontopathogens by polymerase chain reaction (PCR) method. RESULTS: The adjunctive use of the OZO with SRP resulted in a significant improvement (P<0.001) of clinical parameters as well as microbiological parameters over the time and in comparison to the control groups. The OZO as monotherapy also showed a significant improvement (P<0.001) in clinical parameters as well as microbiological parameters over the time without any documented side effects. However, there was a significant increase (P<0.05) in dentinal hypersensitivity following OZO as an adjunct to scaling and root planing therapy. CONCLUSION: The OZO, as an adjunctive therapy as well as a mono-therapy is efficient in improving periodontal conditions.

Magnetoglow: a new geophysical resource.

Evidence has been found that the earth is immersed in a large volume of glowing helium ions. This ionic glow, at 304 angstroms, is similar to the geocoronal hydrogen glow in that it extends to very high altitudes, but it is unique in that it is largely confined to the closed field line portion of the magnetosphere. Because of its magnetic containment, this ionic radiation is called the "magnetoglow." Observations of the magnetoglow from inside and outside the magnetospheric cavity promise to provide a valuable means of studying the structural dynamics of the magnetosphere.

Detection of Lyman-beta and Helium Resonance Radiation in the Night Sky.

A rocket-borne photometer has detected far ultraviolet night glow radiations that are identified as Lyman-beta (HI 1026 angstroms), and the helium lines at 304 or 584 angstroms, or at both. At an altitude of 227 kilometers the measured intensity for Lyman-beta was about 10 rayleighs. The discrimination characteristics of the broad-band helium radiation filter give helium line intensities, at 227 kilometers, of 4.8 and 12 rayleighs, respectively, pending identification of the wavelength of the radiation as 304 or 584 angstroms. These ultraviolet radiations appear sufficient to maintain the night E and F(1) regions of the ionosphere.

Hemodynamic effects of isoproterenol and norepinephrine in acute cardiac tamponade.

The hemodynamic effects of isoproterenol infusion, 0.5 mug/kg per min were evaluated in eight intact anesthetized dogs during cardiac tamponade. During tamponade, the mean of pericardial pressures was increased from - 1.5 to 12.5 mm Hg, and the mean of right atrial pressures was increased from 1 to 12.4 mm Hg. Mean cardiac output fell from 144.8 to 44.8 ml/kg per min (P < 0.001), and rose to 105.6 ml/kg per min (P < 0.001) with isoproterenol. Mean cardiac stroke volume fell from 20.3 to 6.1 ml during tamponade (P < 0.001) and rose to 12.1 ml with isoproterenol (P < 0.001). The heart rate increased from 193.3 beats/min during tamponade to 217.5 beats/min with isoproterenol (P < 0.05). During isoproterenol infusion, the mean right atrial pressure and mean pericardial pressure decreased significantly. With cardiac tamponade, the mean blood pressure fell from 157.5 to 126.1 mm Hg (P < 0.01) and did not change significantly with isoproterenol, 11 additional animals were studied with norepinephrine infusion during tamponade. There were no consistent hemodynamic effects with infusions of 0.5 and 1 mug/kg per min. With norepinephrine 2, 5, and 10 mug/kg per min cardiac output rose in some experiments. Isoproterenol infusion increased the cardiac output during tamponade principally by increasing cardiac stroke volume and to a lesser degree by increasing the heart rate. It is postulated that the increased stroke volume resulted from an increased ejection fraction with greater decrease in end-systolic than end-diastolic ventricular volume. These effects are consistent with the known positive inotropic, peripheral vasodilator, and positive chronotropic effects of isoproterenol.

Hemodynamic effects of phenoxybenzamine in anesthetized dogs.

Our studies demonstrated that phenoxybenzamine, 10 mg/kg, administered intravenously to intact anesthetized dogs, produced an immediate and significant increase of heart rate and cardiac output. In heart-lung preparations, phenoxybenzamine had no effect or a negative cardiac inotropic effect, hence these actions were not related to direct cardiac action or to release of myocardial norepinephrine stores. Serial estimations of arterial blood catecholamines after phenoxybenzamine showed an increase of epinephrine and norepinephrine; the peak values of these catecholamines did not correlate well with the maximum cardiac output responses. Ganglionic blockade largely eliminated the early cardiac effects of phenoxybenzamine, hence its action did not appear to be upon peripheral terminals of postganglionic sympathetic or parasympathetic nerves. Phenoxybenzamine was found to have antivagal actions which might account for some of the delayed cardiac acceleration. When beta adrenergic receptor blockade was induced by sotalol, the cardiac effects of phenoxybenzamine were largely eliminated. Baroreceptor denervation prevented the increase of cardiac output after phenoxybenzamine. These observations are consistent with the concept that the increase of cardiac rate and output produced by phenoxybenzamine is principally mediated by baroreceptor reflexes acting through sympathetic cardiac nerves or circulating catecholamines.

Antibiotic levels in pericardial fluid.

An experimental model was designed to study the ability of antibiotics to enter the pericardial compartment. Noninfected and infected pericardial fluid and serum antibiotic activities were determined in adult mongrel dogs before and at intervals after antibiotic administration. After the administration of penicillin G, methicillin, cephaloridine, streptomycin, or gentamicin, clinically adequate antibiotic levels in the noninfected pericardial fluid were obtained within 1 h, and these levels approached or exceeded the serum levels within 2-4 h. Antibiotic levels obtained from infected dog pericardial fluids were higher than those from noninfected animals. Patients' serum and pericardial fluid antibiotic levels were measured after penicillin G, penicillin V, cephalothin, and gentamicin administration. We have found, both in the canine and human studies, that pericardial antibiotic levels taken at least 2 h after antibiotic administration are almost identical to those in the blood.

Electrocardiographic changes and cardiac arrhythmias in patients receiving psychotropic drugs.

Eight patients had cardiac manifestations that were life-threatening in five while taking psychotropic drugs, either phenothiazines or tricyclic antidepressants. Although most patients were receiving several drugs, Mellaril (thioridazine) appeared to be responsible for five cases of ventricular tachycardia, one of which was fatal in a 35 year old woman. Supraventricular tachycardia developed in one patient receiving Thorazine (chlorpromazine). Aventyl (nortriptyline) and Elavil (amitriptyline) each produced left bundle branch block in a 73 year old woman. Electrocardiographic T and U wave abnormalities were present in most patients. The ventricular arrhythmias responded to intravenous administration of lidocaine and to direct current electric shock; ventricular pacing was required in some instances and intravenous administration of propranolol combined with ventricular pacing in one. The tachyarrhythmias generally subsided within 48 hours after administration of the drugs was stopped. Five of the eight patients were 50 years of age or younger; only one clearly had antecedent heart disease. Major cardiac arrhythmias are a potential hazard in patients without heart disease who are receiving customary therapeutic doses of psychotropic drugs. A prospective clinical trial is suggested to quantify the risk of cardiac complications to patients receiving phenothiazines or tricyclic antidepressant drugs.

Pericarditis caused by Histoplasma capsulatum.

Sixteen patients with pericarditis caused by Histoplasma capsulatum were studied. Fourteen were less than 30 years old, and no patient had an underlying illness or was receiving immunosuppressive therapy. All patients experienced a flu-like prodromal illness lasting from 2 weeks to 4 months. Pneumonitis or hilar adenopathy, or both, was found in 12; pleural effusion, uncommon in primary pulmonary histoplasmosis, was found in seven patients. Pericardial fluid, pleural fluid and bone marrow cultures yielded no growth. All patients demonstrated a fourfold or greater change in complement-fixing antibody titers. No patient had disseminated disease, and only one required treatment with ampholericin B. The illness ran a protracted course, and in six patients symptomatic pericarditis recurred. Ultimately all recovered. Ten patients were restudied 6 months to 12 years after recover. Only one patient had pericardial calcification, and none had constrictive pericarditis. This form of granulomatous pericarditis, unlike that caused by Mycobacterium tuberculosis, appears to carry a good prognosis.

Pentobarbitone inhibition of catecholamine secretion.

1. The perfused isolated cow adrenal gland was used to investigate the effect of barbituric acid, phenobarbitone and pentobarbitone on catecholamine secretion.2. Pentobarbitone reduced catecholamine secretion induced by a number of drugs which cause exocytosis. The concentration of pentobarbitone which caused a 50% inhibition of catecholamine secretion was for acetylcholine 5.6 x 10(-5)M, for carbachol 6.3 x 10(-5)M, for histamine 1.6 x 10(-4)M, for (+)-amphetamine 4.4 x 10(-5)M and for potassium chloride 1.5 x 10(-4)M. The degree of inhibition by pentobarbitone was not dependent on the concentration of the secretagogue.3. Pentobarbitone (up to 10(-3)M) did not inhibit the catecholamine release that was induced by acetyldehyde or by calcium chloride; it inhibited slightly (34%) the catecholamine secretion induced by tyramine.4. Catecholamine release induced by carbachol was also inhibited by phenobarbitone (50% inhibition at 2.8 x 10(-4)M (n=7)) but was unaffected by barbituric acid.5. Pentobarbitone had no effect on spontaneous or on (+)-amphetamine- or tyramine-induced release of catecholamines from isolated chromaffin vesicles of cow adrenal medulla.6. It is concluded that pentobarbitone inhibits catecholamine release by preventing a configurational change in the structure of the membrane of the chromaffin cell which is a necessary link between receptor activation and catecholamine release.

Iliotibial band syndrome in cyclists.

Iliotibial band syndrome is an overuse injury caused by repetitive friction of the iliotibial band across the lateral femoral epicondyle. Once considered an injury indigenous to runners, it is now frequently being seen in cyclists. The purpose of this paper is to identify iliotibial band syndrome as a significant problem in cyclists and to propose both operative and nonoperative measures for treating cyclists. Nonoperative measures specific to cyclists consist of bicycle adjustments and training modifications. These are adjunctive therapies to stretching, icing, rest, and oral nonsteroidal antiinflammatory drugs. For cyclists requiring operative intervention, a new surgical technique for excising or releasing the distal iliotibial band is presented. This technique, used by the senior author (JCH) since 1984, involves excision of an elliptical piece of the distal posterior band off the lateral femoral epicondyle.

The breast radiation injury litigation and the clinical oncologist.

A number of women with breast cancer believed they were suffering injury because radiotherapy had been given negligently. In March 1995, their solicitors were permitted by the High Court, to select 10 cases in order to further a group action. In the legal exchanges which followed, the principal issues put forward by the plaintiffs went through a number of modifications until finally, in December 1997, they were abandoned. Two cases came to trial and after a hearing of 21 days, the Judge found no negligence. Clinical oncologists should be aware of the course of the litigation and consider the lessons to be learned.

Comparison of particle concentration fluorescence immunoassay to card and complement fixation tests using isolation of Brucella abortus as the standard.

Serologic test data and bacteriologic culture results from 816 cattle were evaluated. Brucella abortus (field strain or strain 19) was isolated from 27.3% of the cows. Results of the card test, particle concentration fluorescence immunoassay (PCFIA), and complement fixation (CF) test were compared. Antibody titers were directly associated with B. abortus isolation, with the majority (64.7%) of field strain isolations having a PCFIA value of < or = 0.300 and a CF test result of at least 1+ at a 1:160 dilution. The specificity of the CF test was significantly higher than that of the PCFIA (at CF > or = 1:40 and PCFIA < or = 0.300).

Fusion for instability and potential instability of the cervical spine in children and adolescents.

Instability and potential instability of the cervical spine in the child and adolescent not presenting as emergencies may be due to many causes. We have reviewed 30 patients treated surgically over a seven year period and have grouped them under four general headings: isolated congenital anomalies of the cervical spine, postlaminectomy instability, traumatic instability with delayed presentation, and bony or ligamentous inadequacy secondary to miscellaneous conditions. The variety of conditions permits few generalizations. However, an overview of the entire group supports the concept that abnormal motion in an immature spine or the potential for such motion should be viewed cautiously by the orthopedist, for it may herald severe neurologic compromise. When compromise has occurred, the decision to intervene is made easier. Should only increased motion or the potential for such be present, the natural history of the lesion, if available, should be the guide to treatment. If the natural history of a cervical spine lesion is not available and structural integrity is compromised with abnormal motion present, fusion is advised. Appropriate patient counseling as to the lack of an alternative, with the exception of prolonged bracing to avoid the hazards of life, is essential in this group of individuals.

Functional relationships and microhabitat distributions of enteric helminths of grebes (Podicipedidae): the evidence for interactive communities.

The significance of interspecific interactions as a structuring force in the enteric helminth communities of 4 species of grebes (Aechmophorus occidentalis, Podiceps grisegena, P. nigricollis, and P. auritus) was evaluated. Patterns of microhabitat distribution revealed that helminths resided in predictable locations along the length of the small intestine. Individual species of helminths occupied a high proportion of the intestine and varied in position in different host species suggesting a broad tolerance for conditions along the intestine. However, in individual birds, helminths were much more restricted in distribution, overlapped considerably less than their overall ranges would suggest, congeners had complementary distributions, and there was evidence of interference by at least 1 core species, all suggesting that interactions are important in these communities. Nevertheless, vacant niches were present in most birds, and core species were not distributed more evenly than would be expected through random placement. This suggests that important resources may not be distributed evenly along the intestinal gradient.

Eutrophication, pollution and fragmentation: effects on the parasite communities in roach and perch in four lakes in central Finland.

Parasite communities in the four study lakes reflected the influences of habitat fragmentation, pollution and eutrophication. Discriminant analysis of communities at the individual host level reveal two major axes. One, characterized by reduced numbers of digeneans and myxosporeans and increased numbers of acanthocephalans and monogeneans, contrasts communities in a lake affected by chemical pollution from a pulp mill with two eutrophic, less polluted lakes. Changes in the density of intermediate hosts, direct effects on ectoparasites and impaired immune systems were regarded as important mechanisms. The second contrasts communities in an oligotrophic, unpolluted lake with the two eutrophic lakes, and was more complex, reflecting habitat fragmentation, and pollution or eutrophication, probably mediated by the same mechanisms as above. Monitoring easily seen discriminating parasites following 8 years of reduced pollutant loading showed some, but not all, of the effects of pollution could be reserved in a relatively short time.

Efficacy of ivermectin against nematodes infecting field populations of snowshoe hares (Lepus americanus) in Yukon, Canada.

From July 1990 to February 1991, nematode numbers in free-ranging snowshoe hares (Lepus americanus) at Kluane Lake, southwestern Yukon, Canada, were manipulated by subcutaneous injection (0.4 mg/kg) of ivermectin. Three field experiments were conducted to determine the degree of helminth loss associated with a single administration of ivermectin; the length of time that ivermectin was effective in reducing worm numbers; and the effect of repeated ivermectin administration in reducing worm numbers. Numbers of the nematodes, Protostrongylus boughtoni and Nematodirus triangularis were reduced by approximately 80% 2 wk after treatment with a single dose of ivermectin, and were still significantly lower than controls at 4 wk. However, beyond 2 wk, ivermectin did not affect the rate of acquisition of new worms of either species. All treated groups contained one or more hares in which numbers of P. boughtoni and N. triangularis were not reduced. In addition, ivermectin had no effect on numbers of Trichuris leporis or Passalurus sp. Overall, ivermectin was not as effective against the nematodes of free-ranging hares as has been reported for nematodes of domestic and laboratory animals.

Experimental infections of free-ranging Rocky Mountain bighorn sheep with lungworms (Protostrongylus spp.; Nematoda: Protostrongylidae).

Twelve free-ranging Rocky Mountain bighorn lambs (Ovis canadensis canadensis), each exposed experimentally to 125-1,000 infective third-stage larvae of Protostrongylus stilesi and P. rushi, shed significantly more first-stage larvae in their feces than did control lambs, but showed no clinical signs of illness and had equivalent summer and overwinter survival as control lambs. Two adult ewes, each exposed to 925 infective larvae, showed no increase in numbers of first-stage larvae in their feces; both survived at least 14 mo postexposure. Experimentally exposed lambs did not differ from control lambs in numbers of larvae in their feces in the following summer. Three experimental lambs had 313-402 adult P. stilesi and 0-97 adult P. rushi on necropsy; two control lambs had 255 and 270 P. stilesi and no P. rushi. The presence of these numbers of lungworms did not appear to be sufficient to precipitate lungworm pneumonia in bighorn lambs under the conditions of this study.