Analysis of the 2020 Taal Volcano tephra fall deposits from crowdsourced information and field data

After 43 years of dormancy, Taal Volcano violently erupted in January 2020 forming a towering eruption plume. The fall deposits covered an area of 8605 km², which includes Metro Manila of the National Capital Region of the Philippines. The tephra fall caused damage to crops, traffic congestion, roof collapse, and changes in air quality in the affected areas. In a tropical region where heavy rains are frequent, immediate collection of data is crucial in order to preserve the tephra fall deposit record, which is readily washed away by surface water runoff and prevailing winds. Crowdsourcing, field surveys, and laboratory analysis of the tephra fall deposits were conducted to document and characterize the tephra fall deposits of the 2020 Taal Volcano eruption and their impacts. Results show that the tephra fall deposit thins downwind exponentially with a thickness half distance of about 1.40 km and 9.49 km for the proximal and distal exponential segments, respectively. The total calculated volume of erupted fallout deposit is 0.057 km³, 0.042 km³, or 0.090 km³ using the exponential, power-law, and Weibull models, respectively, and all translate to a VEI of 3. However, using a probabilistic approach (Weibull method) with 90% confidence interval, the volume estimate is as high as 0.097 km³. With the addition of the base surge deposits amounting to 0.019 km³, the volume translates to a VEI of 4, consistent with the classification for the observed height and umbrella radius of the 2020 main eruption plume. VEI 4 is also consistent with the calculated median eruption plume height of 17.8 km and sub-plinian classification based on combined analysis of isopleth and isopach data. Phreatomagmatic activity originated from a vent located in Taal Volcano's Main Crater Lake (MCL), which contained 42 million m³ of water. This eruptive style is further supported by the characteristics of the ash grain components of the distal 12 January 2020 tephra fall deposits, consisting dominantly of andesitic vitric fragments (83-90%). Other components of the fall deposits are lithic (7-11%) and crystal (less than 6%) grains. Further textural and geochemical analysis of these tephra fall deposits contributes to better understand the volcanic processes that occurred at Taal Volcano, one of the 16 Decade Volcanoes identified by the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) because of its destructive nature and proximity to densely populated areas. The crowdsourcing initiative provided a significant portion of the data used for this study while at the same time educating and empowering the community to build resilience.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s00445-022-01534-y.

Detecting Large Vessel Occlusion at Multiphase CT Angiography by Using a Deep Convolutional Neural Network

Background Large vessel occlusion (LVO) stroke is one of the most time-sensitive diagnoses in medicine and requires emergent endovascular therapy to reduce morbidity and mortality. Leveraging recent advances in deep learning may facilitate rapid detection and reduce time to treatment. Purpose To develop a convolutional neural network to detect LVOs at multiphase CT angiography. Materials and Methods This multicenter retrospective study evaluated 540 adults with CT angiography examinations for suspected acute ischemic stroke from February 2017 to June 2018. Examinations positive for LVO (n = 270) were confirmed by catheter angiography and LVO-negative examinations (n = 270) were confirmed through review of clinical and radiology reports. Preprocessing of the CT angiography examinations included vasculature segmentation and the creation of maximum intensity projection images to emphasize the contrast agent-enhanced vasculature. Seven experiments were performed by using combinations of the three phases (arterial, phase 1; peak venous, phase 2; and late venous, phase 3) of the CT angiography. Model performance was evaluated on the held-out test set. Metrics included area under the receiver operating characteristic curve (AUC), sensitivity, and specificity. Results The test set included 62 patients (mean age, 69.5 years; 48% women). Single-phase CT angiography achieved an AUC of 0.74 (95% confidence interval [CI]: 0.63, 0.85) with sensitivity of 77% (24 of 31; 95% CI: 59%, 89%) and specificity of 71% (22 of 31; 95% CI: 53%, 84%). Phases 1, 2, and 3 together achieved an AUC of 0.89 (95% CI: 0.81, 0.96), sensitivity of 100% (31 of 31; 95% CI: 99%, 100%), and specificity of 77% (24 of 31; 95% CI: 59%, 89%), a statistically significant improvement relative to single-phase CT angiography (P = .01). Likewise, phases 1 and 3 and phases 2 and 3 also demonstrated improved fit relative to single phase (P = .03). Conclusion This deep learning model was able to detect the presence of large vessel occlusion and its diagnostic performance was enhanced by using delayed phases at multiphase CT angiography examinations. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Ospel and Goyal in this issue.

Tests of a full-scale ITER toroidal interferometer and polarimeter (TIP) prototype on the DIII-D tokamak (invited)

A full-scale ITER toroidal interferometer and polarimeter (TIP) prototype, including an active feedback alignment system, has been installed and tested on the DIII-D tokamak. In the TIP prototype, a two-color interferometry measurement of line-integrated density is carried out at 10.59 μm and 5.22 μm using a CO₂ and quantum cascade laser, respectively, while a separate polarimetry measurement of the plasma-induced Faraday effect is made at 10.59 μm. The TIP prototype is equipped with a piezo tip/tilt stage active feedback alignment system that minimizes noise in the measurement and keeps the diagnostic aligned throughout DIII-D discharges. The measured phase resolution for the polarimeter and interferometer is 0.05° (100 Hz bandwidth) and 1.9° (1 kHz bandwidth), respectively. The corresponding line-integrated density resolution for the vibration-compensated interferometer is δnL = 1.5 × 10¹⁸ m^-2, and the magnetic field-weighted line-integrated density from the polarimeter is δnBL = 1.5 × 10¹⁹ Tm^-2. Both interferometer and polarimeter measurements during DIII-D discharges compare well with the expectations based on calculations using Thomson scattering measured density profiles and magnetic equilibrium reconstructions. Additionally, larger bandwidth interferometer measurements show that the diagnostic is a sensitive monitor of core density fluctuations with demonstrated measurements of Alfvén eigenmodes and tearing modes.

A heterodyne dispersion interferometer for wide bandwidth density measurements on DIII-D

In order to improve both the density and particularly the temporal resolution beyond previous dispersion interferometers (DIs), a heterodyne technique based on an acousto-optic (AO) cell has been added to the DI. A 40 MHz drive frequency for the AO cell allows density fluctuation measurements into the MHz range. A CO₂ laser-based heterodyne DI (HDI) installed on DIII-D has demonstrated that the HDI is capable of tracking the density evolution throughout DIII-D discharges, including disruption events and other rapid transient phenomena. The data also show good agreement with independent density measurements obtained with the existing DIII-D two-color interferometer. The HDI line-integrated density resolution sampled over a 1 s interval is ∼9 × 10¹⁷ m^-2. Density fluctuations induced by MHD instabilities are also successfully measured by the HDI.

Bench testing of a heterodyne CO2 laser dispersion interferometer for high temporal resolution plasma density measurements

A heterodyne detection scheme is combined with a 10.59 μm CO₂ laser dispersion interferometer for the first time to allow large bandwidth measurements in the 10-100 MHz range. The approach employed utilizes a 40 MHz acousto-optic cell operating on the frequency doubled CO₂ beam which is obtained using a high 2nd harmonic conversion efficiency orientation patterned gallium arsenide crystal. The measured standard deviation of the line integrated electron density equivalent phase resolution obtained with digital phase demodulation technique, is 4 × 10¹⁷ m^-2. Air flow was found to significantly affect the baseline of the phase signal, which an optical table cover was able to reduce considerably. The heterodyne dispersion interferometer (DI) approach is found to be robustly insensitive to motion, with measured phase shifts below baseline drifts even in the presence of several centimeters of retroreflector induced path length variations. Plasma induced dispersion was simulated with a wedged ZnSe plate and the measured DI phase shifts are consistent with expectations.

Upper wide-angle viewing system for ITER

The Upper Wide Angle Viewing System (UWAVS) will be installed on five upper ports of ITER. This paper shows major requirements, gives an overview of the preliminary design with reasons for some design choices, examines self-emitted IR light from UWAVS optics and its effect on accuracy, and shows calculations of signal-to-noise ratios for the two-color temperature output as a function of integration time and divertor temperature. Accurate temperature output requires correction for vacuum window absorption vs. wavelength and for self-emitted IR, which requires good measurement of the temperature of the optical components. The anticipated signal-to-noise ratio using presently available IR cameras is adequate for the required 500 Hz frame rate.

Visceral adipose tissue mass in nonlactating dairy cows fed diets differing in energy density(1)

Our objective was to determine dietary energy effects on feed intake, internal fat deposition, body condition score (BCS), visceral organ mass, and blood analytes in Holstein cows. Eighteen nonpregnant, nonlactating cows (BCS = 3.04 ± 0.25) were blocked based on initial BCS and were randomly assigned within each block to 2 treatments. Treatments were either high energy [HE; net energy for lactation (NEL)=1.62 Mcal/kg] or low energy (LE; NEL = 1.35 Mcal/kg) diets fed as total mixed rations for 8 wk. The LE diet consisted of 81.7% forage, including 40.5% wheat straw and 28.3% corn silage, whereas the HE diet contained 73.8% forage with no straw and 49.9% corn silage (dry matter basis). Cows were fed for ad libitum intake once daily at 0800 h. Feed intake was recorded daily, blood was sampled at wk 1, 4, and 7, and BCS was assigned at wk 1, 4, and 7. Cows were killed following the 8-wk period, and visceral organs, mammary gland, and internal adipose tissues were weighed and sampled. The HE group had greater dry matter intake (15.9 vs. 11.2 ± 0.5 kg/d) and energy intakes than cows fed LE, but neutral detergent fiber intake did not differ (5.8 vs. 5.6 ± 0.25 kg/d for HE and LE). Final body weight was greater for cows fed HE (807 vs. 750 kg), but BCS did not differ between groups (3.52 vs. 3.47 for HE and LE). Omental (26.8 vs. 15.2 ± 1.6 kg/d), mesenteric (21.5 vs. 11.2 ± 1.9 kg), and perirenal (8.9 vs. 5.4 ± 0.9 kg) adipose tissue masses were larger in HE cows than in LE cows. Although subcutaneous adipose mass was not measured, carcass weight (including hide and subcutaneous fat) did not differ between HE (511 kg) and LE (496 kg). Liver weight tended to be greater for cows fed HE, but weights of gastrointestinal tract, heart, and kidney did not differ. Serum insulin tended to be greater and the glucose to insulin ratio was lower for cows fed HE. Serum concentrations of β-hydroxybutyrate and cholesterol were greater for HE cows than for LE cows but concentrations of glucose, nonesterified fatty acids, total protein, and albumin did not differ. Final BCS was correlated with masses of omental (r = 0.57), mesenteric (r = 0.59), and perirenal (r = 0.72) adipose tissue, but mesenteric adipose mass increased more as BCS increased for cows fed HE. The similar final BCS between HE and LE cows demonstrates that BCS may lack sensitivity to detect differences in visceral fat deposition that might increase risk for peripartal diseases and disorders.

Ongoing characterization of the forced electron beam induced arc discharge ion source for the selective production of exotic species facility

An intense research and development activity to finalize the design of the target ion source system for the selective production of exotic species (SPES) facility (operating according to the isotope separation on line technique) is at present ongoing at Legnaro National Laboratories. In particular, the characterization of ion sources in terms of ionization efficiency and transversal emittance is currently in progress, and a preliminary set of data is already available. In this work, the off-line ionization efficiency and emittance measurements for the SPES forced electron beam induced arc discharge ion source in the case of a stable Ar beam are presented in detail.

Photo-ionization of aluminum in a hot cavity for the selective production of exotic species project

SPES (Selective Production of Exotic Species) is an Isotope Separation On-Line (ISOL) based accelerator facility that will be built in the Legnaro-Istituto Nazionale di Fisica Nucleare (INFN) Laboratory (Italy), intended to provide intense neutron-rich radioactive ion beams obtained by proton-induced fission of a uranium carbide (UCx) target. Besides this main target material, silicon carbide (SiC) will be the first to be used to deliver p-rich beams. This target will also validate the functionality of the SPES facility with aluminum beam as result of impinging SiC target with proton beam. In the past, off line studies on laser photoionization of aluminum have been performed in Pavia Spectroscopy Laboratory and in Laboratori Nazionali di Legnaro; a XeCl excimer laser was installed in order to test the laser ionization in the SPES hot cavity. With the new Wien filter installed a better characterization of the ionization process in terms of efficiency was performed and results are discussed.

Studies for aluminum photoionization in hot cavity for the selective production of exotic species project

Selective production of exotic species (SPES) is an ISOL-based accelerator facility that will be built in the Legnaro INFN Laboratory (Italy), intended to provide an intense neutron-rich radioactive ion beams obtained by proton induced fission of an uranium carbide target. Beside this main target, a silicon carbide (SiC) target will the first to be used to deliver some p-rich beams. This target will validate also the functionality of the SPES facility with aluminum beam as result of hitting SiC target with protons. In the past off-line studies on laser photoionization of aluminum have performed in Pavia Spectroscopy Laboratory and in Laboratori Nazionali di Legnaro where, recently, a XeCl excimer laser was installed in order to test the laser ionization in the SPES hot cavity. Results are promising to justify further studies with this technique, aiming a better characterization of the SPES ion extraction capability under laser photoionization.

Off-line ionization tests using the surface and the plasma ion sources of the SPES project

The development of new target ion source systems for the selective production of exotic species (SPES) facility is currently in progress at Legnaro National Laboratories. In this context, the study of ion sources and their performance in terms of ionization efficiency and transversal emittance is a crucial point in order to maximize the available yields, particularly for short-lived isotopes. In this work, preliminary off-line ionization efficiency and emittance measurements for the SPES surface and plasma ion sources are presented. The plasma source emittance measurements are supported by dedicated numerical calculations.

Mosquito vectors of West Nile virus during an epizootic outbreak in Puerto Rico

The purpose of this investigation was to identify the mosquito (Diptera: Culicidae) vectors of West Nile virus (WNV; family Flaviviridae, genus Flavivirus) during an epizootic WNV outbreak in eastern Puerto Rico in 2007. In June 2006, 12 sentinel chicken pens with five chickens per pen were deployed in six types of habitats: herbaceous wetlands, mangrove forests, deciduous forests, evergreen forests, rural areas, and urban areas. Once WNV seroconversion in chickens was detected in June 2007, we began trapping mosquitoes using Centers for Disease Control and Prevention (CDC) miniature (light/CO2-baited) traps, CMT-20 collapsible mosquito (CO2- and ISCA SkinLure-baited) traps, and CDC gravid (hay infusion-baited) traps. We placed the CDC miniature traps both 2-4 m and >30 m from the chicken pens, the collapsible traps 2-4 m from the pens, and the gravid traps in backyards of houses with sentinel chicken pens and in a wetland adjacent to an urban area. We found numerous blood-engorged mosquitoes in the traps nearest to the sentinel chickens and reasoned that any such mosquitoes with a disseminated WNV infection likely served as vectors for the transmission of WNV to the sentinels. We used reverse transcriptase-polymerase chain reaction and isolation (C636) on pools of heads, thoraxes/ abdomens, and legs of collected blood-engorged mosquitoes to determine whether the mosquitoes carried WNV. We detected WNV-disseminated infections in and obtained WNV isolates from Culex nigripalpus Theo (minimum infection rate [MIR] 1.1-9.7/1,000), Culex bahamensis Dyar and Knab (MIR 1.8-6.0/1,000), and Aedes taeniorhynchus (Wied.) (MIR 0.34-0.36/1,000). WNV was also identified in and isolated from the pool of thoraxes and abdomens of Culex quinquefasciatus Say (4.17/1,000) and identified in one pool of thoraxes and abdomens of Culex habilitator Dyar and Knab (13.39/1,000). Accumulated evidence since 2002 suggests that WNV has not become endemic in Puerto Rico.

Study on the precision of the multiaperture scintillation sensor turbulence profiler (MASS) employed in the site testing campaign for the Thirty Meter Telescope

The multiaperture scintillation sensor (MASS) has become a device widely employed to measure the altitude distribution of atmospheric turbulence. An empirical study is reported that investigates the dependence of the MASS results on the knowledge of the instrumental parameters. Also, the results of a side-by-side comparison of two MASS instruments are presented, indicating that MASS instruments permit measurements of the integrated seeing to a precision better than 0.05 arc sec and of the individual turbulence layer strength C(n)(2)(h)dh to better than 10(-14) m(1/3).

Effect of Acute Sublethal Endotoxaemia on In Vitro Digital Vascular Reactivity in Horses

Endotoxaemia is a syndrome linked to the development of equine laminitis; however, the relationship between them is uncertain. The aim of this experiment was to evaluate the effect of an experimental acute sublethal endotoxaemia model on in vitro equine palmar digital vascular reactivity. Rings of arteries and veins of each forelimb were obtained from 11 clinically healthy horses submitted to two surgical procedures, 3 weeks apart. Before the second surgery, 0.25 microg/kg of lipopolysaccharide from Escherichia coli O55:B5 in saline, was administered i.v. in 30 min. After 3 h, the vessels were harvested and submitted to in vitro vascular reactivity experiments and histopathology. The response to depolarizing Krebs solution (DKS, 40 mm), phenylephrine (PHE), acetylcholine (ACh) and sodium nitroprusside (SNP) were evaluated. All horses showed colic pain and watery diarrhoea, tachycardia, tachypnea, hyperthermia and leucopenia. Concentration-response curve (CRC) to PHE was shifted to the left in arteries rings from endotoxemic horses without any effect on vein rings. The CRC to ACh was shifted to the right with a reduction in the maximal response. The response to SNP and DKS was similar between groups. There was no evidence of histopathological effects. The increased response to PHE in digital arteries together with a reduction of the endothelium-dependent response to ACh in arteries and veins, confirm the existing reports where endotoxaemia was found to modify the digital vascular reactivity during the acute phase. As the digital endothelial function is impaired, there may be an increased potential to develop a digital prothrombotic state with a reduced vasodilatory capacity.

Prolonged use of intraluminal arterial shunts without systemic anticoagulation

BACKGROUND

Temporary arterial shunts maintain perfusion while surgeons postpone arterial repairs. The common indications are combined orthopedic and vascular injuries and damage control. The duration of patency and the need for systemic anticoagulation remain in question. We examined our experience for answers.

METHODS

We searched for patients who had temporary arterial shunts and collected the following: mechanism, artery injured, shunt time, blood loss and transfusions, injury severity score (ISS,) mangled extremity severity score (MESS,) and anticoagulation.

RESULTS

Of 19 patients, 10 had shunts for damage control (group 1,) and 9, for orthopedic/vascular injuries (group 2.) group 1 had significantly higher shunt time, mortality, ISS, and MESS. Shunt time ranged from 47 to 3,130 minutes (52 hours.) Two patients, 1 in each group, required amputations.

CONCLUSION

Temporary arterial shunts can be use for combined orthopedic and vascular injuries and for damage control. Shunts can stay open for 52 hours without systemic anticoagulation.

Diabetes and hypertension physiopathology and therapeutics

Diabetes mellitus by itself, is a frequent and increasing public health problem. The prevalence in most Western countries varies between 2 to 5% and it is rapidly increasing in Asiatic countries due to changes in dietary habits during the last years. The association between diabetes mellitus and hypertension has been described in 60 to 65% of diabetics. In hypertension we find insulin resistance mainly in skeletal muscle involving the conversion of glucose to glycogen independently of blood flow. The degree of resistance is related to the severity of hypertension and varies between races. States of hyperinsulinaemia and insulin-resistance have been postulated as causes and/or consequences of hypertension. Regardless of the type of diabetes, hypertension is two to three times more common among diabetics compared with non-diabetics. In this paper we propose to review the essential physiopathological mechanisms involved in this association that causes high morbidity and mortality rates and increases disability among the population involved.

Identification of Cryptosporidium parvum dihydrofolate reductase inhibitors by complementation in Saccharomyces cerevisiae

There is a pressing need for drugs effective against the opportunistic protozoan pathogen Cryptosporidium parvum. Folate metabolic enzymes and enzymes of the thymidylate cycle, particularly dihydrofolate reductase (DHFR), have been widely exploited as chemotherapeutic targets. Although many DHFR inhibitors have been synthesized, only a few have been tested against C. parvum. To expedite and facilitate the discovery of effective anti-Cryptosporidium antifolates, we have developed a rapid and facile method to screen potential inhibitors of C. parvum DHFR using the model eukaryote, Saccharomyces cerevisiae. We expressed the DHFR genes of C. parvum, Plasmodium falciparum, Toxoplasma gondii, Pneumocystis carinii, and humans in the same DHFR-deficient yeast strain and observed that each heterologous enzyme complemented the yeast DHFR deficiency. In this work we describe our use of the complementation system to screen known DHFR inhibitors and our discovery of several compounds that inhibited the growth of yeast reliant on the C. parvum enzyme. These same compounds were also potent or selective inhibitors of the purified recombinant C. parvum DHFR enzyme. Six novel lipophilic DHFR inhibitors potently inhibited the growth of yeast expressing C. parvum DHFR. However, the inhibition was nonselective, as these compounds also strongly inhibited the growth of yeast dependent on the human enzyme. Conversely, the antibacterial DHFR inhibitor trimethoprim and two close structural analogs were highly selective, but weak, inhibitors of yeast complemented by the C. parvum enzyme. Future chemical refinement of the potent and selective lead compounds identified in this study may allow the design of an efficacious antifolate drug for the treatment of cryptosporidiosis.

Advances in the generation of transgenic pigs via embryo-derived and primordial germ cell-derived cells

The development of new technologies that would increase the efficiency for generation of transgenic livestock and would overcome some of the problems associated with random insertion of the transgene will greatly benefit animal agriculture. A potential alternative technology to pronuclear injection for the generation of transgenic pigs involves the isolation, culture and genetic manipulation of cell lines that can be reintroduced into the embryo for participation in the formation of the germ cells. We have isolated and cultured pig primordial germ cells (PGC) while maintaining them in an undifferentiated state as determined by morphology and alkaline phosphatase (AP) activity. More importantly, PGC-derived cells were stably transformed with the green fluorescent protein marker driven by the cytomegalovirus promoter. After visual identification of transgenic colonies, the pluripotential characteristics of the transgenic PGC-derived cells were tested by chimaera formation and to date we have identified, by genomic Southern blots, two chimaeric fetuses that contain tissues with the transgene incorporated into their chromosomes. To our knowledge, this is the first report of a chimaeric transgenic pig fetus obtained via a cultured cell line.

Techniques of treatment of peritoneal endometriosis: the cavitational ultrasonic surgical aspirator

The efficacy of medical therapy in endometriosis-associated infertility has been called into question. For decades, surgery has been used in the treatment of endometriosis. However, before the 1960s it consisted of either excision or hysterectomy and bilateral adnexectomy. Although controversy exists about whether laparotomy or operative laparoscopy is the more efTective therapeutic approach for endometriosis, the efficacy of surgery in reducing implants, relieving dysmenorrhea and pelvic pain, and improving fertility has been well-established.

[Direct negative inotropic effect of cocaine in rat ventricle strip]

Cocaine, when used as a recreative drug, can induce cardiovascular toxic effects such as acute reduction of left ventricle ejection fraction, which indicates a negative inotropic effect of the drug. The purpose of this study was to clarify the direct negative inotropic effect of cocaine in in vitro conditions. Rat right ventricle strips were incubated in Krebs solution gassed with 95% O2 and 5% CO2 at 37 degrees, and electrically driven with 2 ms square pulses, 17 mA, at 110 systoles/min. Separate experiments were conducted to study cocaine effect at 210 and 310 systoles/min. The contractile force was recorded through a strain-gauge isometric transducer. Cocaine increased contractile force at doses of 0.3-10.0 micrograms/ml, up to 53% over basal contraction. In the presence of 4 x 10(-8) M atenolol, low doses of cocaine did not increase contractile force and at doses between 3.0-10.0 micrograms/ml revealed a depressant activity on heart muscle contractions. Doxazosin (1.0 microM) and yohimbine (0.1 microM) did not modify the positive inotropic effect of cocaine, showing that alpha 1 and alpha 2 adrenergic receptors were not involved in this cocaine ventricle action. Increasing ventricle strip stimulation rate to 210 and 310 systoles/min for 30 seconds, the contractile force was risen by 55% and 95%, respectively. Cocaine at doses 1.0-3.0 micrograms/ml did not modify the physiological increase of contractile force seen upon ventricle rate increase. The mechanism involved in the contractile force increment after ventricle rate increase is a transient rise of cytosolic Ca2+, mainly derived from the sarcoplasmic reticulum and from extracellular fluid. Atenolol (4 x 10(-8) M) exposure of the right ventricle strip intensified the negative inotropic effect of cocaine (3.0-10 micrograms/ml) seen by ventricle stimulation at 210 and 310 systoles/min. The myocardial direct depressant effect of cocaine, in the presence of atenolol, was gradually reversed by extracelular Ca2+ increase at 3.2 and 5.0 mM, respectively. In conclusion, the mechanism of myocardial direct depressant effect of cocaine is related to the beating frequency of the ventricle, which may be associated to interference with the Ca2+ release process from the myocite sarcoplasmic reticulum, and not to calcium entry blockade from extracellular fluid. However, a dpressant effect of cocaine on phase "0" of depolarization, related to its local anesthetic properties can not be ruled out.

The efficacy of epinephrine test doses during spinal anesthesia in volunteers: implications for combined spinal-epidural anesthesia

Epinephrine test doses may be administered during combined spinal-epidural anesthesia to determine intravascular placement of epidural catheters. This study was designed to determine systolic blood pressure (SBP) and heart rate (HR) responses to intravenous injection of epinephrine (15 microg) during spinal anesthesia. Twelve volunteers received three spinal anesthetics (lidocaine 100 mg, tetracaine 15 mg, and bupivacaine 15 mg) in a randomized, double blind, cross-over fashion. Epinephrine was administered prior to spinal anesthesia (control), 30 min after injection of spinal anesthesia, and at regression of sensory block to T-10. SBP was measured with a radial arterial catheter and HR with an electrocardiogram. Positive responses were defined as peak increase in SBP > or = 15 mm Hg or HR > or = 20 bpm after injection of epinephrine. Compared with control, peak SBP responses decreased by a mean of 12 mm Hg during spinal anesthesia with tetracaine and bupivacaine (P < 0.05). Peak HR responses decreased by 11 bpm during all three spinal anesthetics (P < 0.05). Incidences of detection of intravenous injection by positive SBP and HR responses ranged from 50% to 100% and were not significantly affected by spinal anesthesia. Spinal anesthesia reduces hemodynamic responses to intravenous epinephrine injection but is unlikely to reduce detection by positive SBP and HR criteria.

Respiratory manifestations of tick-borne diseases in the Southeastern United States

Pulmonary signs and symptoms may provide important differential clues to the diagnosis of tick-borne illness incurred in the southern United States.

Treatment of patients with essential hypertension: amlodipine 5 mg/benazepril 20 mg compared with amlodipine 5 mg, benazepril 20 mg, and placebo

This multicenter, double-masked, randomized, parallel-group study compared the efficacy, tolerability, and safety of amlodipine 5 mg/benazepril 20 mg, amlodipine 5 mg, benazepril 20 mg, and placebo in patients with essential hypertension. After a placebo run-in period, 308 patients (all white) were randomized to treatment groups and took medication once daily for 8 weeks. Blood pressure was measured after 4 and 8 weeks of treatment in the 23- to 26-hour period after dosing. Patients wore a noninvasive blood pressure monitor for 24 hours before randomization and before the final visit. Investigators recorded adverse experiences at randomization and at study weeks 4 and 8, and obtained specimens for laboratory testing at randomization and at study week 8. Three hundred seven patients were evaluated for efficacy, and 308 for tolerability and safety. At end point (the last postrandomization measurement for each patient), the reduction in mean sitting diastolic blood pressure with the amlodipine 5 mg/benazepril 20 mg treatment was statistically significantly greater than with any comparative therapy. The results of 24-hour monitoring showed that the amlodipine/benazepril treatment, unlike monotherapy, maintained the hourly mean diastolic blood pressure at < or = 90 mm Hg. A responder rate of 87.0% was observed with amlodipine 5 mg/benazepril 20 mg versus 67.5%, 53.3%, and 15.8% with amlodipine, benazepril, and placebo, respectively. This difference between the amlodipine/benazepril treatment group and each comparative single-agent treatment group was statistically significant. Drug-related adverse events occurred in 15.6% of patients in the amlodipine/benazepril group and in 24.7%, 6.5%, and 11.7% of patients in the amlodipine, benazepril, and placebo groups, respectively. Edema occurred less often in the amlodipine/benazepril group than in the amlodipine group. Overall, once-daily therapy with amlodipine 5 mg/benazepril 20 mg provided an antihypertensive effect that was statistically and clinically superior to amlodipine 5 mg alone, benazepril 20 mg alone, and placebo, was well tolerated, and was associated with less edema than the amlodipine treatment.

Antigenic differences associated with genetically distinct Pneumocystis carinii from rats

Pneumocystis carinii is a family of organisms found in a wide variety of mammalian lungs. In immunocompromised hosts, the organisms are able to produce an oftentimes fatal pneumonia. The existence of distinct types of Pneumocystis populations is strongly supported by antigenic and genetic evidence. In the present study, we assessed the antigenic profiles of two genetically distinct Pneumocystis carinii populations, P. carinii f. sp. carinii and P. carinii f. sp. ratti, as well as two types of P. carinii f. sp. carinii defined by electrophoretic karyotyping (forms 1 and 2). The separated and blotted proteins of the organism preparations were probed with four monoclonal antibodies (MAbs) generated to the major surface glycoproteins of rat-derived P. carinii, one anti-human P. carinii MAb, and two polyclonal antisera made with rat-derived P. carinii as the immunogen. Differences in reactivities between the P. carinii f. sp. carinii and P. carinii f. sp. ratti preparations were detected with two of the MAbs, and both of the rat P. carinii polyclonal antisera in the 45- to 55-kDa molecular mass range, but not with the human P. carinii MAb. The reactivities of the 16 P. carinii f. sp. carinii preparations were the same with two exceptions. Two preparations of form 1 showed strong reactivity with the anti-MSG MAb RA-C11. The ratios of cyst forms to trophic forms evaluated by microscopy were not associated with any of the differences observed in the antigenic profiles. The antigenic differences between P. carinii f. sp. carinii and P. carinii f. sp. ratti are consistent with the distinction of these two populations made by molecular genetic techniques, while the two differences detected among the P. carinii f. sp. carinii preparations suggest the organism may be able to modulate antigenic epitopes. The use of immunoblotting to differentiate infecting organism populations and assess antigenic modulation holds promise for future epidemiologic studies.

Expression of apple 1-aminocyclopropane-1-carboxylate synthase in Escherichia coli: kinetic characterization of wild-type and active-site mutant forms

The pyridoxal phosphate-dependent enzyme 1-aminocyclopropane-1-carboxylate synthase (ACC synthase; S-adenosyl-L-methionine methylthioadenosine-lyase, EC 4.4.1.14) catalyzes the conversion of S-adenosylmethionine (AdoMet) to ACC and 5'-methylthioadenosine, the committed step in ethylene biosynthesis in plants. Apple ACC synthase was overexpressed in Escherichia coli (3 mg/liter) and purified to near homogeneity. A continuous assay was developed by coupling the ACC synthase reaction to the deamination of 5'-methylthioadenosine by adenosine deaminase (adenosine aminohydrolase, EC 3.5.4.4) from Aspergillus oryzae. The enzyme is dimeric, with kcat = 9s-1 per monomer and Km = 12 microM for AdoMet. The pyridoxal phosphate-binding site of ACC synthase appears to be highly homologous to that of aspartate aminotransferase, suggesting similar roles for corresponding residues. Site-directed mutagenesis of Lys-273, Arg-407, and Tyr-233 (corresponding to residues 258, 386, and 225 in aspartate aminotransferase) and kinetic analyses of the mutants confirms their importance in the ACC synthase mechanism. The Lys-273 to Ala mutant has no detectable activity, supporting the identification of this residue as the base catalyzing C alpha proton abstraction. Mutation of Arg-407 to Lys results in a precipitous drop in kcat/Km and an increase in Km for AdoMet of at least 20-fold, in accordance with its proposed role as principal ligand for the substrate alpha-carboxylate group. Replacement of Tyr-233 with Phe causes a 24-fold increase in the Km for AdoMet and no change in kcat, suggesting that this residue plays a role in orienting the pyridoxal phosphate cofactor in the active site.

Determination of pefloxacin concentration in mesenteric lymph nodes by high-performance chromatography

Ten patients who had undergone laparotomies for different abdominal pathological conditions were studied to determine the levels of pefloxacin in mesenteric lymph nodes. Each patient was given 400 mg of oral pefloxacin every 12 h for the 3 days prior to surgery. Drug levels in tissue were determined by high-pressure liquid chromatography (reverse phase); the mean +/- standard deviation was 17.1 +/- 11.9 micrograms/g, with a range of 2.12 to 36.6 micrograms/g. This indicates an adequate pefloxacin concentration in lymph nodes and makes the drug a good option for the treatment of conditions in which lymph nodes act as an infection-promoting and/or relapse-favoring factor.

Conventional and color Doppler transvaginal sonography in gynecologic infertility. Current clinical applications

TVS affords accurate follicular monitoring and guidance for follicular aspiration. The role of TVS in assessing the adequacy of the endometrium is still undergoing investigation. Our studies suggest that there is a statistically significant difference in the pregnancy rate when the endometrium has a multilayered appearance. Infertility patients who successfully achieve pregnancy should be monitored with TVS because of a higher incidence of ectopic pregnancy, anembryonic gestation, and spontaneous abortion. TVS has a secondary role in evaluating certain uterine malformations and tubal disorders. With TV-CDS it is also possible to evaluate physiologic parameters such as adnexal and uterine blood flow. The role of TV-CDS in the anatomic and physiologic evaluation of early pregnancy is now being established.

A prospective, randomized, double-blind, crossover study to compare the efficacy and safety of chronic nifedipine therapy with that of isosorbide dinitrate and their combination in the treatment of chronic congestive heart failure

We performed a prospective, randomized, double-blind, crossover study to compare the efficacy and safety of vasodilation with the calcium entry blocker nifedipine with that of isosorbide dinitrate (ISDN) and their combination as treatment for heart failure. Twenty-eight patients with New York Heart Association Functional class II or III chronic heart failure due to left ventricular systolic dysfunction were studied. All patients were maintained on a constant dose of digitalis and diuretics throughout the study. Eight weeks of therapy with nifedipine alone or in combination with ISDN resulted in a significantly higher incidence of heart failure deterioration necessitating hospitalizations and/or additional diuretics. Twenty-four percent of patients required hospitalization during nifedipine therapy and 26% required hospitalization during nifedipine-ISDN combination therapy in comparison to 0% requiring hospitalization during ISDN therapy alone. The total number of heart failure-worsening episodes was nine among patients on nifedipine, three among patients on ISDN (p less than 0.09 versus nifedipine), and 21 among patients on nifedipine-ISDN combination (p less than 0.001 versus nifedipine, p less than 0.0001 versus ISDN). Premature discontinuation of drug administration due to clinical deterioration or other side effects occurred in 29% of patients during nifedipine therapy, 5% of patients during ISDN therapy (p = 0.05 versus nifedipine), and 19% of patients during the combination therapy. A comparison of eight patients who demonstrated clinical deterioration on nifedipine with the remainder of the patients demonstrated no significant difference in left ventricular ejection fraction (0.24 +/- 0.06 versus 0.23 +/- 0.07) or maximal oxygen uptake during exercise (13 +/- 3 versus 14 +/- 2 ml/kg/min).(ABSTRACT TRUNCATED AT 250 WORDS)

Central and renal hemodynamic effects of a new agonist at peripheral dopamine- and beta-2 adrenoreceptors (dopexamine) in patients with heart failure

The effect of dopexamine, a new dopamine analogue, on central and renal hemodynamics was evaluated in nine patients with chronic, congestive heart failure caused by severe left ventricular (LV) systolic dysfunction. The administration of the maximally tolerated dose (7.2 +/- 4 micrograms/kg/min) resulted in a significant increase in cardiac index from 1.9 +/- 0.4 L/min/m2 to 2.6 +/- 0.9 L/min/m2 (p less than 0.05). This increase in cardiac index was largely a result of increase in heart rate (from 88 +/- 20 beats/min to 104 +/- 24 beats/min, p less than 0.05), because stroke volume index demonstrated only a small change (from 23 +/- 10 ml/m2 to 27 +/- 11 ml/m2, p not significant) in spite of a significant fall in systemic vascular resistance from 1992 +/- 717 dynes.sec.cm-5 to 1361 +/- 524 dynes.sec.cm-5 (p less than 0.05) and diastolic blood pressure (from 89 +/- 15 mm Hg to 80 +/- 17 mm Hg, p less than 0.05). No change was seen during dopexamine infusion in systolic blood pressure, right and left ventricular filling pressures, and LV stroke work index. Both renal blood flow and glomerular filtration rate were impaired at baseline in most patients. Dopexamine administration resulted in a significant increase (2x coefficient of variation) in renal blood flow in two patients only. Mean values of both renal blood flow and glomerular filtration rate did not show significant change (485 +/- 183 ml/min vs 563 +/- 221 ml/min and 89 +/- 39 ml/min vs 93 +/- 34 ml/min, respectively, p not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

A nontoxic adjuvant treatment for advanced head and neck cancer

A variety of adjuvant chemotherapy programs have been described for advanced head and neck cancer. The protocol described herein is nontoxic and particularly appropriate for patients with advanced tumors who cannot, because of severe pulmonary disease, tolerate bleomycin sulfate. Eighty percent of patients treated with this combination responded with more than 50% tumor shrinkage. Chemotherapy was followed by either surgery, radiation therapy, or both. Long-term control with this combined modality therapy was better in oral cavity and oropharyngeal lesions than in tumors from the hypopharynx.

The role of estrogens in mastopathy and mammary cancer in perimenopausal women

Fibrocystic disease of the breast (FCD) is an exaggeration of the normal physiologic response to cyclic estrogen and progesterone stimulation. The disorder can persist, with much less severity, in the menopausal woman. Whether FCD predisposes to mammary cancer remains moot. A new steroidal agent, danazol, can eliminate nodosities in the majority of women with FCD. Thermography may identify women who are at greater risk because of increased heat production. Mammography should be employed in women with persistently abnormal thermograms, even though no suggestive breast masses are palpable. Needle biopsy or surgical biopsy should be undertaken whenever a firm indurated mass is palpated, regardless of negative findings with a thermogram or mammogram. In a series of 1548 women treated for 10,715 women-years, the incidence of breast cancer after prolonged estrogen therapy was not increased. Although estrogens and prolactin have been incriminated in the etiology of mammary cancer, no hard facts exist to confirm such allegations.

Fibrocytic breast disease: current status of diagnosis and treatment

Improved diagnostic procedures and use of a new steroidal agent, danazol (Danocrine), should reduce the need for surgical intervention in fibrocystic breast disease. Thermography, a non-invasive procedure that may be used with impunity, may help identify women at high risk. Mammography, which is useful in revealing malignancy in an early stage, should be done in women with tow consecutive abnormal thermograms. Biopsies should be performed, however, on suspicious, firm, irregular masses, regardless of results on thermography or mammography. Use of danazol may be advantageous not only in ameliorating pain and eliminating nodosities, but also in guiding the surgeon to the nodule that is unresponsive to treatment and therefore should be evaluated by biopsy.

Observations on the antigenicity and clinical effects of a candidate antipregnancy vaccine: beta-subunit of human chorionic gonadotropin linked to tetanus toxoid

Observations on the antibody response and clinical effects of injection of purified beta-subunit of human chorionic gonadotropin covalently linked to tetanous toxoid were made in 15 healthy young women who had previously undergone tubal ligation. Antibodies detectable by radioimmunoassay were found in 14 of the women. Clinical surveillance and immunologic, hematologic, and biochemical tests indicated excellent local and systemic tolerance to the antigen. No significant adverse effects on menstrual function, endocrine status, or health were found.

The cholinergic pathway to cerebral blood vessels. I. Morphological studies

The application of cobalt chloride to the peripheral cut end of the greater superficial petrosal nerve (g.s.p.n.) in rats revealed that only a few fibers in the plexus of nerves on the adventitial surface of the internal carotid artery were in axonal continuity with the g.s.p.n. A similarly small contribution of cholinergic fibers to cerebral blood vessels from this nerve was suggested by the observation that section of the g.s.p.n. resulted in an insignificant reduction in the density of the AChE-staining plexus in the internal carotid and cerebral arteries and in the incidence of at most 2% degenerate terminals of those observed on the middle cerebral artery. Alternative explanations of the results are discussed: that the AChE-staining fibers are postganglionic, that the time course for degeneration is unusually slow and that non-cholinergic fibers stain non-specifically for AChE. It is concluded that a cholinergic dilator pathway is most probably carried by the g.s.p.n. but that it is not unique.