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Objective: The goal of this study was to assess the effectiveness and tolerability of olanzapine in the treatment of acute mania in children and adolescents., Methods: This was an 8-week, open-label, prospective study of olanzapine monotherapy (dose range 2.5-20 mg/day) involving 23 bipolar youths (manic, mixed, or hypomanic; 5-14 years old). Weekly assessments were made using the Young Mania Rating Scale (YMRS), Clinical Global Impressions Severity Scale (CGI-S), Brief Psychiatric Rating Scale, and Children's Depression Rating Scale. Adverse events were assessed through self-reports, vital sign and weight monitoring, laboratory analytes, and extrapyramidal symptom rating scales (Barnes Akathisia Scale, Simpson-Angus Scale, and Abnormal Involuntary Movement Scale)., Results: Twenty-two of the 23 youths (96%) completed the study. Olanzapine treatment was associated with significant improvement in mean YMRS score (-19.0 +/- 9.2, p < 0.001). Using predefined criteria for improvement of > or = 30% decline in the YMRS and a CGI-S Mania score of < or = 3 at endpoint, the overall response rate was 61%. Overall, olanzapine was well tolerated, and extrapyramidal symptom measures were not significantly different from baseline. Body weight increased significantly over the study (5.0 +/- 2.3 kg, p < 0.001)., Conclusions: Open-label olanzapine treatment was efficacious and well tolerated in the treatment of acute mania in youths with bipolar disorder. Future placebo-controlled, double-blind studies are warranted.

Molecular hydrogen (H2) is by far the most abundant material from which stars, protoplanetary disks and giant planets form, but it is difficult to detect directly. Infrared emission lines from H2 have recently been reported towards beta Pictoris, a star harbouring a young planetary system. This star is surrounded by a dusty 'debris disk' that is continuously replenished either by collisions between asteroidal objects or by evaporation of ices on Chiron-like objects. A gaseous disk has also been inferred from absorption lines in the stellar spectrum. Here we present the far-ultraviolet spectrum of beta Pictoris, in which H2 absorption lines are not seen. This allows us to set a very low upper limit on the column density of H2: N(H2) 6 x 10-4. As CO would be destroyed under ambient conditions in about 200 years (refs 9, 11), our result demonstrates that the CO in the disk arises from evaporation of planetesimals.

The ultraviolet groove efficiency for a holographically ruled diffraction grating with a trapezoidal profile has been measured. The efficiencies for the +/-1 and the zero orders are in good agreement with those derived from scalar theory. The +/-1 orders have equal efficiency as a function of wavelength. The peak of the sum of fitted groove efficiency functions is 76%, a level that is competitive with the groove efficiency of a mechanically blazed grating. We suggest that a normal-incidence grating mount with detectors at both orders will offer a system with twice the efficiency and provide a built-in redundancy. We discuss design considerations for reducing astigmatism equally in both orders in such dual-order mountings.

At least 16 fragments were detected in images of comet C/1999 S4 (LINEAR) taken on 5 August 2000 with the Hubble Space Telescope (HST) and on 6 August with the Very Large Telescope (VLT). Photometric analysis of the fragments indicates that the largest ones have effective spherical diameters of about 100 meters, which implies that the total mass in the observed fragments was about 2 x 10(9) kilograms. The comet's dust tail, which was the most prominent optical feature in August, was produced during a major fragmentation event, whose activity peaked on UT 22.8 +/- 0.2 July 2000. The mass of small particles (diameters less than about 230 micrometers) in the tail was about 4 x 10(8) kilograms, which is comparable to the mass contained in a large fragment and to the total mass lost from water sublimation after 21 July 2000 (about 3 x 10(8) kilograms). HST spectroscopic observations during 5 and 6 July 2000 demonstrate that the nucleus contained little carbon monoxide ice (ratio of carbon monoxide to water is less than or equal to 0.4%), which suggests that this volatile species did not play a role in the fragmentation of C/1999 S4 (LINEAR).

Background: Elderly patients with Alzheimer's disease (AD) commonly exhibit psychotic symptoms, prompting clinicians to administer antipsychotics. This article compares the effects of olanzapine and placebo in the emergence of hallucinations or delusions in AD patients with symptoms of agitation/aggression but little or no psychotic symptomatology at baseline., Method: A multicenter, double-blind, placebo-controlled study was conducted in nursing home patients with AD according to DSM-IV criteria and symptoms of agitation/aggression and/or psychosis. Patients (N = 206) were randomly assigned to receive either placebo or fixed-dose olanzapine (5, 10, or 15 mg/day) for up to 6 weeks. This article analyzes data from a subgroup of patients (N = 165) with no or minimal delusions and/or hallucinations at baseline as measured by the Neuropsychiatric Inventory-Nursing Home Version (NPI/NH). Three subsets of patients were identified on the basis of their symptoms at baseline: those with no clinically significant hallucinations, those with no clinically significant delusions, and those with no clinically significant delusions or hallucinations., Results: Of the patients without hallucinations or delusions at baseline (N = 75), the placebo-treated patients showed significantly greater development of these symptoms compared with olanzapine-treated patients overall (NPI/NH hallucinations + delusions mean change score, +2.73 vs. +0.27, p = .006). Similarly, of the patients without baseline hallucinations (N = 153), the placebo-treated patients showed greater hallucinations score increases than did olanzapine-treated patients overall (+1.25 vs. +0.33, p = .026), whereas patients without baseline delusions (N = 87) showed no significant treatment effects. Olanzapine had a favorable safety profile in each patient subset., Conclusion: These results suggest that, overall, olanzapine effectively attenuated emergence of psychosis in a short-term trial of patients with Alzheimer's disease.

Background: Patients with Alzheimer disease (AD) commonly exhibit psychosis and behavioral disturbances that impair patient functioning, create caregiver distress, and lead to institutionalization. This study was conducted to assess the efficacy and safety of olanzapine in treating psychosis and/or agitation/aggression in patients with AD., Methods: A multicenter, double-blind, placebo-controlled, 6-week study was conducted in 206 elderly US nursing home residents with AD who exhibited psychotic and/or behavioral symptoms. Patients were randomly assigned to placebo or a fixed dose of 5, 10, or 15 mg/d of olanzapine. The primary efficacy measure was the sum of the Agitation/Aggression, Hallucinations, and Delusions items (Core Total) of the Neuropsychiatric Inventory-Nursing Home version., Results: Low-dose olanzapine (5 and 10 mg/d) produced significant improvement compared with placebo on the Core Total (-7.6 vs -3.7 [P<.001] and -6.1 vs -3. 7 [P =.006], respectively). Core Total improvement with olanzapine, 15 mg/d, was not significantly greater than placebo. The Occupational Disruptiveness score, reflecting the impact of patients' psychosis and behavioral disturbances on the caregiver, was significantly reduced in the 5-mg/d olanzapine group compared with placebo (-2.7 vs -1.5; P =.008). Somnolence was significantly more common among patients receiving olanzapine (25.0%-35.8%), and gait disturbance occurred in those receiving 5 or 15 mg/d (19.6% and 17.0%, respectively). No significant cognitive impairment, increase in extrapyramidal symptoms, or central anticholinergic effects were found at any olanzapine dose relative to placebo., Conclusion: Low-dose olanzapine (5 and 10 mg/d) was significantly superior to placebo and well tolerated in treating agitation/aggression and psychosis in this population of patients with AD.

Introduction: An important consideration in treating acute mania is the promptness with which a chosen therapy can bring symptom amelioration. This article reviews the available published data from controlled, blinded studies regarding the latency of responses to antipsychotics in patients with acute mania., Methods: Articles for this review were obtained from a search of the Medline database (1966- 1999), using the following keywords and phrases: antipsychotic, atypical, bipolar disorder, mania, neuroleptic, typical. The bibliographic sections of articles gleaned from this search were used to direct further inquiries., Results: Although information regarding the onset of action of antipsychotics is limited, we discovered data for four typical and three atypical antipsychotics. Drugs with the fastest onsets include haloperidol, risperidone, and olanzapine, with onsets appearing in 2 6 days. Chlorpromazine and thiothixene were at the slowest end of the continuum, with onsets of 2 weeks or longer. Data regarding pimozide are mixed, with some studies showing an onset equivalent to that of the 'fast' compounds and others showing one similar to that of the 'slow' compounds., Conclusions: Choice of therapy should consider not only efficacy and safety, but also onset speed. Atypical antipsychotics appear to offer safer, faster, and more effective therapies.

Well-resolved far-ultraviolet spectroscopic images of O I, S I, and previously undetected H ILyman-alpha emission from Io were obtained with the Hubble space telescope imaging spectrograph (STIS). Detected O I and S I lines (1250 to 1500 angstroms) have bright equatorial spots (up to 2.5 kilorayleighs) that shift position with jovian magnetic field orientation; limb glow that is brighter on the hemisphere facing the jovian magnetic equator; and faint diffuse emission extending to approximately 20 Io radii. All O I and S I features brightened by approximately 50 percent in the last two images, concurrently with a ground-based observation of increased iogenic [O I] 6300-angstrom emission. The H ILyman-alpha emission, consisting of a small, approximately 2-kilorayleigh patch near each pole, has a different morphology and time variation.

Narcissistic ghost lines in a Rowland-grating spectrograph have been identified as arising from the reimaging of bright spectral features, which are incident on the face of a detector photocathode [Cesium iodide (CsI) on a microchannel plate], back onto the detector by the grating in zero order. The mean of the wavelength of the diffracted light and the apparent wavelength of the ghost allows the angle of the grating normal with respect to the input beam (alpha) to be determined. Measurements of ghost intensity as a function of wavelength are presented and are found to range between 7 x 10(-4) and 7 x 10(-3) of the parent line. We find that the sum of the CsI photocathode reflectivity and quantum efficiency <1/2, showing the bulk of the light incident upon the detector, is neither reflected nor detected. We caution that any Rowland circle spectrograph with a detector normal nearly aligned with the grating normal and with a sufficiently reflective detector face (or surrounding mounting structure) will suffer from these narcissistic ghosts.

An image of comet Hale-Bopp (C/1995 O1) in soft x-rays reveals a central emission offset from the nucleus, as well as an extended emission feature that does not correlate with the dust jets seen at optical wavelengths. Neon was found to be depleted in the cometary ice by more than a factor of 25 relative to solar abundance, which suggests that ices in Hale-Bopp formed at (or later experienced) temperatures higher than 25 kelvin. A helium line emission at a wavelength of 584 angstroms was detected and may be attributable to charge transfer of solar wind alpha particles in the cometary coma. Ionized oxygen and another helium line contribute to an emission observed at 538 angstroms.

Analysis of Hubble Space Telescope (HST) images of comet Hale-Bopp (C/1995 O1) suggests that the effective diameter of the nucleus is between 27 to 42 kilometers, which is at least three times larger than that of comet P/Halley. The International Ultraviolet Explorer and HST spectra showed emissions from OH (a tracer of H2O) and CS (a tracer of CS2) starting in April 1996, and from the CO Cameron system (which primarily traces CO2) starting in June 1996. The variation of the H2O production rate with heliocentric distance was consistent with sublimation of an icy body near its subsolar point. The heliocentric variation in the production rates of CS2 and dust was different from that of H2O, which implies that H2O sublimation did not control the CS2 or dust production during these observations.

Just before earth passed through Saturn's ring plane on 10 August 1995, the Hubble Space Telescope Faint Object Spectrograph detected ultraviolet fluorescent emissions from a tenuous atmosphere of OH molecules enveloping the rings. Brightnesses decrease with increasing distance above the rings, implying a scale height of about 0.45 Saturn radii (Rs). A spatial scan 0.28Rs above the A and B rings indicates OH column densities of about 10(13) cm(-2) and number densities of up to 700 cm(-3). Saturn's rings must produce roughly 10(25) to 10(29) OH molecules per second to maintain the observed OH distribution.

Microinjections of Leu-enkephalin into the dorsal vagal complex induced hypotension and bradycardia. Both naloxone, given at a dose conferring selectivity for mu receptors, and the delta antagonist ICI 154,129 prevented the cardiovascular effects of Leu-enkephalin. Naloxone was also found to decrease the gain of the baroreflex. These results suggest that Leu-enkephalin is involved in cardiovascular regulation through activation of delta-, and possibly mu-, opioid receptors in the dorsal vagal complex.

Spontaneous neuronal activity in the solitary tract nucleus was recorded extracellularly in a brain slice preparation during bath-application of 5-HT1 and 5-HT2 receptor-selective agonists and antagonists. The 5-HT1A/5-HT1B agonist 5-carboxamidotryptamine depressed activity in 20 of 25 neurons studied. The remaining five neurons were unaffected. The 5-HT1A/5-HT1B antagonist pindolol prevented the 5-carboxamidotryptamine-induced changes, whereas the 5-HT1A antagonist spiroxatrine and the 5-HT2 antagonists ketanserin and mianserin were ineffective. Application of the 5-HT1/5-HT2 agonist alpha-methylserotonin depressed activity in 16 of 19 neurons, whereas the remaining three neurons were unresponsive. Pindolol blocked alpha-methylserotonin-induced changes of activity, but spiroxatrine, ketanserin and mianserin were ineffective. Finally, the 5-HT2 agonist DOI was applied to seven neurons. Six were unresponsive to DOI, and one responded with a depression of activity. These data provide electrophysiological evidence for the presence of 5-HT1 receptors in the nTS, presumably of the 5-HT1B subclass, but cast further doubt on the contribution of 5-HT2 and 5-HT1A receptors to the actions of serotonin in the nucleus.

The UV quantum efficiency of a Scientific Imaging Technologies (SITe, Beaverton, Ore., formerly Tektronix) 1024 pixel by 1024 pixel thinned and backside-illuminated charge-coupled device has been measured in the wavelength band from 1164 to 5200 Å. The 24-µm-pixel device, which does not have an antireflective coating, has an average quantum efficiency of more than 40% in the band from 1164 to 4000 Å and a read noise of 15 e(-)/pixel.

The cardiovascular regulatory role of serotonin [5-hydroxytryptamine (5-HT)] in the solitary tract nucleus (NTS) was investigated in urethan-anesthetized Wistar rats. Unilateral microinjection of 5-HT (5 nmol in 50 nl) into the NTS evoked depressions of both arterial pressure (-20 +/- 1 mmHg) and heart rate (-43 +/- 6 beats/min). Induction of bradycardia and hypotension was repeatable and consistently obtained with injections into the NTS but not into neighboring structures. Microinjection of the nonselective 5-HT receptor antagonist methiothepin or the 5-HT1A/5-HT1B antagonist pindolol prevented any cardiovascular change by subsequent microinjection of 5-HT into the NTS. In contrast, microinjection of the 5-HT2-selective antagonist ketanserin or the 5-HT1A antagonist spiroxatrine had no effect on the subsequent effects of 5-HT. Bilateral vagal denervation prevented the bradycardia induced by 5-HT, whereas the vasodepression remained intact. These data provide evidence that 5-HT in the NTS evokes vagal chronotropic cardioinhibition and sympathetic withdrawal and suggest that this action is mediated by 5-HT1 serotonergic receptors, possibly of the 5-HT1B subtype.

The involvement of substance P (SP) in cardiovascular regulatory mechanisms was investigated in the nucleus of the tractus solitarius (nTS) of urethane-anesthetized Wistar rats. Unilateral microinjections of SP (0.25 pmol in 50 nl) or the neurokinin (NK) 1 agonist [Sar9,Met(O2)11]-SP (0.25 pmol) resulted in decreases of blood pressure and heart rate when placed in the nTS but not in neighboring structures. Bilateral vagotomy abolished SP-induced bradycardia but did not prevent the vasodepression. Microinjection of the NK2 agonist alpha-NKA[4-10] (0.25 and 1.25 pmol) or the NK3 agonist senktide (0.25 and 1.25 pmol) had no effect on arterial pressure or heart rate. The relatively non-selective tachykininergic antagonist [D-Pro2,D-Trp7.9]-SP (10 pmol in 100 nl) and the NK1 antagonist cyclo(Gln-D-Trp-(N-Me)-Phe(R)Gly[ANC-2]Leu-Met)2 (1.25 pmol) prevented the cardiovascular effects of both SP and the NK1 agonist, whereas the NK2 antagonist cyclo(GlnTrpPheGlyLeuMet) was ineffective. Neither of the effective antagonists affected resting blood pressure, heart rate or the gain or threshold of the baroreflex. These data indicate that SP acts in the nTS via NK1 receptors to evoke a vagally-mediated bradycardia and a hypotension that is independent of changes of heart rate and suggest further that SP is not integral to the circuitry subserving the baroreflex.

The Hubble Space Telescope made systematic observations of the split comet P/Shoemaker-Levy 9 (SL9) (P designates a periodic comet) starting in July 1993 and continuing through mid-July 1994 when the fragments plunged into Jupiter's atmosphere. Deconvolutions of Wide Field Planetary Camera images indicate that the diameters of some fragments may have been as large as approximately 2 to 4 kilometers, assuming a geometric albedo of 4 percent, but significantly smaller values (that is, < 1 kilometer) cannot be ruled out. Most of the fragments (or nuclei) were embedded in circularly symmetric inner comae from July 1993 until late June 1994, implying that there was continuous, but weak, cometary activity. At least a few nuclei fragmented into separate, condensed objects well after the breakup of the SL9 parent body, which argues against the hypothesis that the SL9 fragments were swarms of debris with no dominant, central bodies. Spectroscopic observations taken on 14 July 1994 showed an outburst in magnesium ion emission that was followed closely by a threefold increase in continuum emission, which may have been caused by the electrostatic charging and subsequent explosion of dust as the comet passed from interplanetary space into the jovian magnetosphere. No OH emission was detected, but the derived upper limit on the H2O production rate of approximately 10(27) molecules per second does not necessarily imply that the object was water-poor.

Europa, the second large satellite out from Jupiter, is roughly the size of Earth's Moon, but unlike the Moon, it has water ice on its surface. There have been suggestions that an oxygen atmosphere should accumulate around such a body, through reactions which break up the water molecules and form molecular hydrogen and oxygen. The lighter H2 molecules would escape from Europa relatively easily, leaving behind an atmosphere rich in oxygen. Here we report the detection of atomic oxygen emission from Europa, which we interpret as being produced by the simultaneous dissociation and excitation of atmospheric O2 by electrons from Jupiter's magnetosphere. Europa's molecular oxygen atmosphere is very tenuous, with a surface pressure about 10(-11) that of the Earth's atmosphere at sea level.

The absolute quantum efficiency (QE) of two 1024 × 1024 pixel phosphor-coated (lumigen) chargecoupled devices has been measured in the band from 1216 to 5200 Å. It is found that the average QE is 17.7 ± 1.8% for the lot 1 detector and 18.1 ± 1.8% for the lot 2 detector in the band from 1600 to 3800 Å. The sensitivity rises on the long-wavelength side of the measurement band to 32% at 5200 Å and falls with the wavelength below 1600 Å. The two detectors have different spatial uniformity characteristics; both have a very uniform response (±2%) to 5200-Å flat-field illumination, although only one of the devices has a flat ultraviolet response. The read noise of these devices is 8 electrons (e(-)).

The nucleus tractus solitarius (nTS) is an important site for the integration of visceral information and its modification by afferent neural systems. One such afferent system arises from the raphe nuclei. This study investigated the electrophysiological effects of the primary transmitter of the raphe nuclei, serotonin (5-HT), on neurones in the nTS of the rat. Extracellular single unit recordings were made of the spontaneous activity of nTS neurones in isolated, superfused brainstem slices during bath-application of 5-HT (50, 100, 250, 500, 1000 nM). Twenty-seven of 46 neurones studied (approximately 59%) showed concentration-dependent decreases of firing rate, with a calculated EC50 of 261 nM. An additional 3 neurones displayed excitatory responses, while the remaining 16 were unaffected. The broad-spectrum 5-HT1 antagonist methysergide (200 nM) was highly effective in producing blockade of 5-HT-evoked depressions of neuronal activity (4 of 4), whereas the 5-HT1A receptor-selective antagonist spiroxatrine (5 nM) and the 5-HT2-selective antagonist mianserin (200 nM) were considerably less effective (1 of 5 and 2 of 5, respectively). Seven additional neurones were examined during exposure to the 5-HT1-selective agonist 5-carboxamidotryptamine (5-CT) or the 5-HT2-selective agonist DOI. 5-CT depressed the activity of three of the four neurones tested, the remaining neurone being unresponsive at concentrations up to 50 nM. DOI at concentrations up to 100 nM failed to affect the activity of two of the three neurones tested, and depressed the activity of the third at a concentration of 50 nM.(ABSTRACT TRUNCATED AT 250 WORDS)

The Hubble Space Telescope observed the fragmented comet P/Shoemaker-Levy 9 (1993e) (P indicates that it is a periodic comet) on 1 July 1993. Approximately 20 individual nuclei and their comae were observed in images taken with the Planetary Camera. After subtraction of the comae light, the 11 brightest nuclei have magnitudes between approximately 23.7 and 24.8. Assuming that the geometric albedo is 0.04, these magnitudes imply that the nuclear diameters are in the range approximately 2.5 to 4.3 kilometers. If the density of each nucleus is 1 gram per cubic centimeter, the total energy deposited by the impact of these 11 nuclei into Jupiter's atmosphere next July will be approximately 4 x 10(30) ergs ( approximately 10(8) megatons of TNT). This latter number should be regarded as an upper limit because the nuclear magnitudes probably contain a small residual coma contribution. The Faint Object Spectrograph was used to search for fluorescence from OH, which is usually an excellent indicator of cometary activity. No OH emission was detected, and this can be translated into an upper limit on the water production rate of approximately 2 x 10(27) molecules per second.

In the solitary tract nucleus, neuronal responsiveness to synaptic input from peripheral afferent fibres has been found to decrease as the frequency of that input is increased. The present study investigated the possibility that glycine and gamma-aminobutyric acid (GABA) are (1) involved in this phenomenon of "frequency-dependent inhibition" or (2) capable of otherwise modifying neuronal responsiveness to synaptic input. In 32 of 57 neurones, application of glycine reduced responsiveness to input from visceral afferents. gamma-Aminobutyric acid reduced the responsiveness in 22 of 56 neurones but induced an increase in another 6. Selectivity of agonist effects was verified using glycinergic antagonist strychnine and the GABAergic antagonists picrotoxin and bicuculline. Of 67 neurones examined, 32 exhibited decreased numbers of action potentials with increasing stimulus frequency. Strychnine disrupted the frequency-dependent inhibition in 3 of 11 neurones, while picrotoxin and bicuculline prevented it in 2 of 7 and 4 of 9 neurones, respectively. These results indicate that both glycinergic and GABAergic systems may modulate the responsiveness of neurones in the solitary tract nucleus but that neither fully accounts for the expression of frequency-dependent inhibition.

Anatomical and pharmacological evidence suggests a role for catecholamines (CAs) in the modulation of the baroreceptor reflex within the nucleus tractus solitarii (NTS). Single neurons in the NTS of the rat were studied for their responses to activation of the baroreceptor reflex and to iontophoretic administration of dopamine, norepinephrine (NE), and epinephrine (EPI) to determine the relationship between the effects of baroreflex activation and CA application on baroreceptive neurons in the vagal sensory nucleus. Of 269 cells studied, 104 (38.7%) exhibited decreases and 41 cells (15.2%) showed increases in firing rate in response to baroreflex activation, while the remaining 124 neurons showed no response. All 3 CAs inhibited spike activity in the majority (68.5%) of NTS cells. These inhibitory effects on spontaneous firing were observed regardless of the response profile of a particular neuron to baroreflex activation. The inhibitory effects of NE and EPI on NTS neuronal activity were specifically blocked by the alpha-adrenergic receptor antagonist tolazoline, but not by the beta-adrenergic antagonist sotalol. These results indicate that CAs may interact at several sites within the NTS to influence baroreflex integration, and that the effects of NE and EPI on neuronal activity are mediated by an alpha-adrenergic receptor.

Studies were made of the effects of the alpha 1-adrenoceptor agonist methoxamine on spontaneous and synaptically evoked activity in the solitary tract nucleus in isolated, perfused slices of the brain of the rat and those effects were compared to the effects of the alpha 2-agonist clonidine. Methoxamine had no effect on the spike activity of 7 out of 8 spontaneously firing neurones, with no response to electrical stimulation of the solitary tract. Among neurones that responded to tract stimulation, those which were otherwise silent (N = 38) showed a decrease of responsiveness to tract input during the infusion of methoxamine, whereas those with spontaneous activity (N = 10) showed mostly increases of both firing rate and responsiveness. The effects of activation of alpha 2-receptors on responsiveness to tract stimulation were the opposite of previously demonstrated effects of activation of alpha 2-receptors, and these opposing effects could be demonstrated in the same neurone. These results suggest that the transmission of visceral sensory information within the nucleus tractus solitarius may be controlled by opposing alpha 1- and alpha 2-receptor-mediated neural systems.

The cranium-to-alveolus bone graft is an alternate method of reconstructing the posterior and lateral midfacial pillars where local reconstruction is not possible.

Extravasation of intravenous phenytoin can result in serious soft-tissue complications. Three patients are presented, one of whom lost a hand. Assessment of circulation and early decompression fasciotomies may be necessary in such cases. Caution is recommended in the intravenous administration of phenytoin. Infusions at rates of less than 50 mg/min and education of nursing staff about this potential complication will decrease its incidence.

These studies examined the effects of the alpha-adrenergic agonist clonidine on spontaneous and synaptically evoked activity in the solitary tract nucleus in superfused rat brain slices. In one group of neurons which showed no spontaneous spike activity (n = 27), clonidine superfusion induced a dose-dependent increase of postsynaptic responsiveness to input from the ipsilateral solitary tract. In another group of neurons which were spontaneously active but unresponsive to tract input (n = 20), clonidine induced a dose-dependent depression of spontaneous discharge. A third group of neurons which were both spontaneously active and responsive to tract input (n = 11) showed primarily a depression of both activities. The neuronal responses to clonidine in all 3 groups were selectively blocked by the alpha 2-adrenoceptor antagonist yohimbine but not by the alpha 1-antagonist prazosin. These results provide insight into the possible actions of endogenous adrenergic systems in the synaptic processing of afferent sensory information within the solitary tract nucleus.

Observations of Comet Kohoutek (1973f) in the spectral region between 1200 and 3200 angstroms were made from an Aerobee rocket on 5.1 January 1974 universal time. The strongest features observed were the Lyman alpha line of neutral atomic hydrogen at 1216 angstroms and the hydroxyl (OH) bands at 3090 and 3142 angstroms. Atomic oxygen and atomic carbon were also detected, and their luminosity implies a production rate (of carbon monoxide or carbon dioxide) commensurate with that of water vapor.

Our current knowledge of the composition of the cormetary nucleus is largely inferred from observations of the gas and dust comae that are produced by sublimation of cometary ice when a comet is near the sun. During the past decade, far-ultraviolet spectroscopy from above the terrestrial atmosphere has shed new light on the physics and chemistry of the gaseous component of the coma. The advent of interplanetary missions to Halley's comet in 1986 and the development of a new generation of earth-orbiting observatories promise further insights into the nature of these frozen remnants of the primordial solar system.

A liquid-helium-cooled Ebert-Fastie grating spectrometer for use in a sounding rocket is described. Twelve detectors and associated filters separate the 5-70-microm spectral range into twelve intervals, each of which is scanned as the grating is rotated. The instrument was launched into an aurora from Fort Churchill, Canada, but a cryogenic failure occurred early in the flight, and only a small amount of data was obtained.

A telescope for rocket-borne ir astronomy is described. It consists of a 166-mm cassegrainian telescope cooled to liquid helium temperature and operated with a total radiation chopper. Details of the optical, cryogenic, and electronic designs are given.

An ultraviolet spectrometer aboard the Apollo 17 orbiting spacecraft attempted to measure ultraviolet emissions from the lunar atmosphere. The only emissions observed were from a transient atmosphere introduced by the lunar landing engine. The absence of atomic hydrogen implies that solar wind protons are converted to hydrogen molecules at the lunar surface.

In the absence of a thermal radiation background, it is possible to obtain a very high responsivity with far ir extrinsic photoconductive detectors. Using a low noise liquid helium-cooled preamplifier, we have obtained an NEP of 10(-14) W Hz(-(1/2)) for Ge: Ga at 100 micro in an instrument designed for rocket ir astronomy. The limiting noise factor appears to be generation recombination noise due to thermal excitation of other impurities present in the germanium.