Asynchronies of diphenhydramine plasma-performance relationships

The relation between performance on driving-related tasks and plasma levels of diphenhydramine was studied in eight male volunteers over 24 hours following oral administration. DPH plasma concentrations rose to peak levels in 1.5-2.5 hours varying with dose, declining to a nearly constant level by 12-24 hours. For all behavioral measures, the shape of performance curves over time was similar to that of plasma, reaching maximum decrements in 1-4 hours. The relation between plasma levels and performance was asynchronous varying with behavioral measure and dose. The use of plasma DPH values to predict performance decrements is limited due to the bivalued nature of these relationships in time. Nonetheless, it would appear that if DPH is administered in the therapeutic dosage range at the intervals typically recommended for cold symptoms and allergies, it appears some aspects of human performance may be impaired.

Emergence of compulsive behavior and tantrums in children with Prader-Willi syndrome

Many adults with Prader-Willi syndrome are affected by behaviors such as tantrums, skin-picking, and compulsions. The nature and extent of these problems suggest more attention be directed to their emergence in childhood. Our purpose was to investigate behavior problems in children with this syndrome and identify the age at which these behaviors emerge. Parents of children with Prader-Willi syndrome, Down syndrome, and those developing typically completed questionnaires. Children with Prader-Willi syndrome exhibited more compulsions, skin-picking, and tantrums than did the other groups. A discriminant analysis of behavior variables derived two statistically significant functions that were interpreted as developmental milestones and problematic behavior. These functions correctly predicted membership for 79% of grouped cases.

Biofuel Options for Marine Applications: Technoeconomic and Life-Cycle Analyses

This study performed technoeconomic and life-cycle analyses to assess the economic feasibility and emission benefits and tradeoffs of various biofuel production pathways as an alternative to conventional marine fuels. We analyzed production pathways for (1) Fischer-Tropsch diesel from biomass and cofeeding biomass with natural gas or coal, (2) renewable diesel via hydroprocessed esters and fatty acids from yellow grease and cofeeding yellow grease with heavy oil, and (3) bio-oil via fast pyrolysis of low-ash woody feedstock. We also developed a new version of the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) marine fuel module for the estimation of life-cycle greenhouse gas (GHG) and criteria air pollutant (CAP) emissions of conventional and biobased marine fuels. The alternative fuels considered have a minimum fuel selling price between 2.36 and 4.58 $/heavy fuel oil gallon equivalent (HFOGE), and all exhibit improved life-cycle GHG emissions compared to heavy fuel oil (HFO), with reductions ranging from 40 to 93%. The alternative fuels also exhibit reductions in sulfur oxides and particulate matter emissions. Additionally, when compared with marine gas oil and liquified natural gas, they perform favorably across most emission categories except for cases where carbon and sulfur emissions are increased by the cofed fossil feedstocks. The pyrolysis bio-oil offers the most promising marginal CO₂ abatement cost at less than $100/tonne CO₂e for HFO prices >$1.09/HFOGE followed by Fischer-Tropsch diesel from biomass and natural gas pathways, which fall below $100/tonne CO₂e for HFO prices >$2.25/HFOGE. Pathways that cofeed fossil feedstocks with biomass do not perform as well for marginal CO₂ abatement cost, particularly at low HFO prices. This study indicates that biofuels could be a cost-effective means of reducing GHG, sulfur oxide, and particulate matter emissions from the maritime shipping industry and that cofeeding biomass with natural gas could be a practical approach to smooth a transition to biofuels by reducing alternative fuel costs while still lowering GHG emissions, although marginal CO₂ abatement costs are less favorable for the fossil cofeed pathways.

Controlling a new plasma regime

Success of the UK's Spherical Tokamak for Energy Production (STEP) programme requires a robust plasma control system. This system has to guide the plasma from initiation to the burning phase, maintain it there, produce the desired fusion power for the desired duration and then terminate the plasma safely. This has to be done in a challenging environment with limited sensors and without overloading plasma-facing components. The plasma parameters and the operational regime in the STEP prototype will be very different from tokamaks, which are presently in operation. During fusion burn, the plasma regime in STEP will be self-organizing, adding further complications to the plasma control system design. This article describes the work to date on the design of individual controllers for plasma shape and position, magneto hydrodynamic instabilities, heat load and fusion power. Having studied 'normal' operation, the article discusses the philosophy of how the system will handle exceptions, when things do not go exactly as planned. This article is part of the theme issue 'Delivering Fusion Energy - The Spherical Tokamak for Energy Production (STEP)'.

An assessment of mother-to-child HIV transmission prevention in 16 pilot antenatal clinics in Jamaica

OBJECTIVES

This study aims to determine the number and age distribution of pregnant women testing positive for HIV at 16 selected clinics in Jamaica between 2001 and 2002; the utilization of therapeutic interventions to minimize the risk of mother-to-child transmission (MTCT) and the current status of the HIV-exposed infants and, finally, the number of children who received testing for detection of HIV and to calculate the incidence of MTCT in these children.

METHODS

A retrospective study was carried out at sixteen pilot clinic sites by examining the patient records for all confirmed HIV-positive pregnant mothers and the resultant infants at these facilities for the period January 2001 to December 2002.

RESULTS

One hundred and twenty-three of 8116 pregnant women newly tested positive during the period January 2001 to December 2002; however, 176 HIV+ women delivered. Fifty-three (30%) knew their HIV status prior to participating in the programme. Sixty-two (1.4%) and 61 (1.6%) tested positive in 2001 and 2002, respectively. One hundred and ten (77%) and 113 (83%) mothers and infants, respectively, received ARV therapy, (92% - nevirapine, 8% - zidovudine). Twenty-three per cent of pregnant women received no ARV Forty-four (25.0%) of the 176 infants had a documented ELISA HIV test before eighteen months of age, none had a PCR test. The health status of 40 (23%) of these children was known: 30 (75%) were alive and well, five of whom did not receive any ARV, one (2.5%) was alive and ill and nine (22.5%) were reported dead, five of whom received ARV; 28.6% of infants who did not receive ARV were reported as either dead or ill compared to 13.8% of those receiving ARV CONCLUSION: Though the majority of pregnant women discovered their HIV status during pregnancy, a significant number got pregnant knowing that they were HIV+. The majority of mothers and infants received ARV but the follow-up and testing of infants was limited. Nevirapine is clearly protective in the prevention of MTCT of HIV and should be made universally accessible. All infants delivered to HIV+ mothers should be identified and tested for HIV.

Forearm P-31 nuclear magnetic resonance spectroscopy studies in oculopharyngeal muscular dystrophy

Five siblings with autosomal dominant oculopharyngeal muscular dystrophy (OPMD) underwent P-31 Nuclear Magnetic Resonance Spectroscopy studies of forearm flexor muscles. Mean values of PCr/(PCr+Pi) in the patients were reduced (p = 0.01) and pH elevated (p = 0.02) in resting muscle when compared to controls. During exercise PCr/PCr+Pi) fell quickly to values less than controls (p less than 0.0001) despite submaximal exercise output and developed exercise-induced acidosis which exceeded that of controls (p = 0.05). Acidosis recovered slowly despite relatively normal recovery of PCr/(PCr+Pi) following exercise. Within the patient group, however, one member had normal resting, exercise and recovery values. The studies suggest that OPMD is a more widespread disorder of striated muscle than clinically appreciated. The pattern of findings observed in OPMD differs from those identified in denervation, disuse and mitochondrial myopathy.

Studies of rhenium carboxylates as antitumor agents. Part II. Antitumor studies of bis (mu-propionato) diaquotetrabromodirhenium (III) in tumor-bearing mice

The neutral, dimeric complexes of rhenium, bis (mu-carboxalato)-diaquotetrahalodirhenium (III) (carboxalato = acetato, propionato, or butyrato and halo = chloro or bromo), were synthesized and survival studies were done on mice bearing P-388 leukemia or B-16 melanoma. The complex bis (mu-propionato) diaquotetrabromodirhenium (III) proved to be the most effective in increasing the life span of the mice. The complex showed some activity against B-16, but virtually none against P-388. The complexes are all quite non-toxic.

Architectural features and perceptions of community residences for people with mental retardation

Architects, group home administrators, people with mental retardation, family members of people with mental retardation, and college undergraduates substantially agreed regarding the rated homelikeness of slides of interiors of 20 community residences for people with mental retardation ranging from institutional to homey, mean r = .87. Clusters of physical features identified using an architectural inventory were found to be associated with homelikeness ratings. Adjectives applied to rooms with these features were determined using a Q-sort method. Two factors were identified from Q-sort correlations: Homelikeness-Institutionality and Spatial Organization as well as a third variable, privacy.

In vivo disposition and metabolism by liver and enterocyte microsomes of the antitubercular drug rifabutin in rats

The in vivo disposition and in vitro metabolism of rifabutin, a new spiropiperidylrifamycin, were studied in rats and in microsomes from rat liver and enterocytes, respectively. After i.v. doses of 1,5, 10 and 25 mg/kg the systemic clearance was 0.7 to 1.0 liters/hr/kg; the volume of distribution was 4.4 liters/kg for the 1 mg/kg dose and 7.4 to 7.7 liters/kg for the 5 to 25 mg/kg doses, and the half-life ranged from 4.4 to 9.1 hr. Urinary and fecal excretion over 0 to 96 hr after i.v. administration of 25 mg/kg [14C]rifabutin accounted for 40.1 and 52.2% of the dose, respectively. Exteriorization of the bile duct showed that approximately 24% of the dose was eliminated in bile, > or = 98% as metabolites. Bioavailability after oral administration of 25 and 1 mg/kg rifabutin was > 90% and 44%, respectively, suggesting significant first-pass metabolism of the lower dose. Concentrations of rifabutin in gastric juice were 10 to 17 times higher than in blood, indicating extensive secretion into the stomach. Experiments with the isolated small intestinal loop demonstrated direct exsorption of the drug into the lumen. The rate of rifabutin metabolism by enterocyte microsomes was > 10 times higher than that by liver microsomes, i.e., 84 and 8 pmol/min/mg protein, respectively. Biotransformation of rifabutin in vivo and in vitro was markedly induced by dexamethasone and inhibited by erythromycin, suggesting that CYP3A is involved in the metabolism of rifabutin. Several metabolites, including 20-OH-rifabutin and 27-O-demethyl-rifabutin, isolated from urine and microsomes were identified by mass spectrometry and nuclear magnetic resonance spectroscopy.

Hepatic transcatheter arterial chemoembolization alternating with systemic protracted continuous infusion 5-fluorouracil for gastrointestinal malignancies metastatic to liver: a phase II trial of the Puget Sound Oncology Consortium (PSOC 1104)

We assessed a regimen of alternating regional and systemic therapy in patients with gastrointestinal malignancies with liver-dominant metastases for feasibility, toxicity, response rate, response duration, patterns of progression, and progression-free and overall survival. Regional therapy comprised selective hepatic transcatheter arterial chemoembolization (TACE) using a suspension of cisplatin and particulate polyvinyl alcohol. This procedure was delivered between cycles of protracted continuous infusion 5-fluorouracil (PCI-5FU) as systemic chemotherapy. Patient eligibility criteria included: (a) having histologically documented adenocarcinoma arising from a gastrointestinal primary site with unresectable liver metastases bidimensionally measurable on computerized tomography scan; (b) age greater than 18 years; and (c) performance status 0-2 (Zubrod). PCI-5FU (250 mg/m2/day) was administered i.v. for 28 days, followed by the first TACE (TACE 1) delivered to the hepatic artery supplying the lobe with the greatest tumor burden. Restaging was performed before TACE 2 and TACE 3, which followed at monthly intervals. PCI-5FU for 21 days was sandwiched between each of the TACE treatments. After the final TACE, maintenance PCI-5FU was given for 28 days of each 35-day cycle until toxicity or progression. Between December 23, 1991, and January 19, 1995, 32 patients were registered in this trial, of whom 27 were eligible; 20 completed one or more treatment cycles and were evaluable for radiographic response. Patients with colorectal liver metastases predominated (74%). Twelve (44%) of 27 patients had failed one or more prior treatment regimens. There were no treatment-related deaths, and hematological and hepatic toxicities were generally manageable and reversible. Two patients, however, developed hepatic abscesses requiring drainage, and one patient developed an infarcted gallbladder, which necessitated cholecystectomy. There were no patients with complete responses; there were 8 (40%) with partial responses, 4 (20%) with minor responses, 2 (10%) with stable disease, and 6 (30%) who progressed on the treatment. The median duration of response for partial responders was 4.2 months (127 days; range, 56-245 days). The median reduction in carcinoembryonic antigen for responders was 87.5%. Two patients underwent subsequent resection of residual metastases; one of them is still alive at 58.4 months follow-up. The predominant site of disease progression was the liver; 25% of the patients progressed in extrahepatic sites. The median overall survival for the whole group is 14.3 months (95% confidence interval, 7.2-16.2). Actuarial overall survival for the whole group at 1 year and 2 years is 57 and 19%, respectively. Alternating systemic PCI-5FU and regional TACE (cisplatin/polyvinyl alcohol) is an active and feasible regimen with manageable toxicities in patients with metastatic gastrointestinal malignancies with liver-dominant disease and merits further investigation. The complications seen were in line with those reported at other specialized centers.

Ketamine self-administration by the rhesus monkey

Intravenously administered ketamine served as a reinforcer of self-administration behavior in rhesus monkeys during daily 2-hour sessions. When the dose of ketamine was varied over a wide range at fixed-ratio schedules of reinforcement of 1, 8 and 64, the response rate was an inverted U-shaped function of the dose. Maximal response rates occurred at progressively higher doses as the fixed-ratio size was increased; drug intake per session was positively related to the dose. When the ketamine dose was held constant and the fixed-ratio was increased in a geometric series, the response rate increased as the fixed-ratio was increased to FR 128 or FR 256; additional increases in fixed-ratio size produced abrupt decreases in response rates. Since the response rate increased linearly as the fixed-ratio was increased geometrically, drug intake was a decreasing function of the response requirement. With respect to magnitude of reinforcement and fixed-ratio response requirement, the data show that ketamine maintains self-administration behavior in a manner similar to that of a number of other drugs and conventional reinforcers.

Nonconvulsive Status Epilepticus after Subarachnoid Hemorrhage

P58

Background: In-hospital seizures have been reported in 3–24% of patients with aneurysmal subarachnoid hemorrhage (SAH). Nonconvulsive status epilepticus (NCSE) after SAH has not been previously described. Methods: Between 11/97 and 2/00, we performed continuous electroencephalographic (cEEG) monitoring (Nicolet Bravo system) for at least 24 hours in all SAH patients treated in our NICU with unexplained coma or neurologic deterioration. Electrographic seizures were diagnosed when epileptiform discharges with a discrete onset, offset, and evolution were present on cEEG. All seizures were treated aggressively with intravenous anticonvulsants and continuous-infusion midazolam therapy, as necessary. Results: Of 233 SAH patients who survived the first 48 hours of hospitalization, 100 were stuporous or comatose during their hospitalization. Twenty-six of these patients underwent cEEG monitoring, and 8 (31%) were diagnosed with NCSE average of 18 days (range 5–38) after SAH. Five patients were persistently comatose, two deteriorated to stupor, and one deteriorated to coma with eye blinking; none had focal tonic-clonic activity. All patients were on an anticonvulsant at the time of diagnosis. All seizures were partial, consisting of rhythmic runs of epileptiform discharges; only 4 had focal CT pathology related to the seizure focus. Seizure control was achieved in five patients, but only one experienced clinical improvement, which was transient; in the other 3, the seizures could not be controlled. All 8 patients eventually died in the hospital after a period of prolonged coma (mean LOS 51 days); all but 1 had life support withdrawn. In a univariate analysis, increased mean age (68 vs 54 yrs), higher APACHE-2 scores (16 vs 10), Fisher 3/4 blood on CT (100% vs 54%), worst Hunt/Hess grade 4/5 (100% vs 44%), and ventricular drainage (88% vs 36%) were identified as risk factors for NCSE (all P=.005). Conclusion: NCSE may occur in 5–10% of SAH patients who deteriorate or fail to awaken from coma. Although the seizures can be terminated with medical treatment, the prognosis for these patients is extremely poor.