A single dose of dietary nitrate supplementation protects against endothelial ischemia-reperfusion injury in early postmenopausal women

The onset of menopause and accompanying changes to ovarian hormones often precedes endothelial dysfunction in women. In particular, accelerated impairments in macrovascular and microvascular function coincide with the loss of estrogen, as does impaired endothelial responses to ischemia-reperfusion (IR) injury. In healthy, early postmenopausal women (n = 12; 3.9 ± 1.5 years since menopause) we tested the hypothesis that acute dietary nitrate (NO3-) supplementation would improve endothelial function and attenuate the magnitude of endothelial dysfunction following whole-arm IR in comparison with placebo. In this randomized, double-blind, placebo-controlled, crossover study we tested participants before and after NO3--rich (BRnitrate) and NO3--depleted (BRplacebo) beetroot juice (BR) consumption, as well as following IR injury, and 15 min after IR to assess recovery. Analyses with repeated-measures general linear models revealed a condition × time interaction for brachial artery flow-mediated dilation (FMD; P = 0.04), and no interaction effect was found for the near-infrared spectroscopy-derived reperfusion slope (P = 0.86). Follow-up analysis showed a significant decline in FMD following IR injury with BRplacebo in comparison with all other timepoints (all, P < 0.05), while this decline was not present with BRnitrate (all, P > 0.05). Our findings demonstrate that a single dose of dietary NO3- minimizes IR-induced macrovascular endothelial dysfunction in healthy, early postmenopausal women, but does not improve resting macrovascular and microvascular function. Trial registration number: NCT03644472. Novelty: In healthy, early postmenopausal women, a single dose of NO3--rich BR can protect against IR-induced endothelial dysfunction. This protection may be due to nitric oxide bioactivity during IR rather than improved endothelial function prior to the IR protocol per se.

Preventing and Addressing the Stress Reactions of Health Care Workers Caring for Patients With COVID-19: Development of a Digital Platform (Be + Against COVID)

Background

COVID-19 became a major public health concern in March 2020. Due to the high rate of hospitalizations for COVID-19 in a short time, health care workers and other involved staff are subjected to a large workload and high emotional distress.

Objective

The objective of this study is to develop a digital tool to provide support resources that might prevent and consider acute stress reactions in health care workers and other support staff due to the COVID-19 pandemic.

Methods

The contents of the digital platform were created through an evidence-based review and consensus conference. The website was built using the Google Blogger tool. The Android version of the app was developed in the Java and XML languages using Android Studio version 3.6, and the iOS version was developed in the Swift language using Xcode version 11.5. The app was evaluated externally by the Andalusian Agency for Healthcare Quality.

Results

We detected the needs and pressing situations of frontline health care workers, and then, we proposed a serial of recommendations and support resources to address them. These resources were redesigned using the feedback received. A website in three different languages (Spanish, English, and Portuguese) and a mobile app were developed with these contents, and the AppSaludable Quality Seal was granted to the app. A specific self-report scale to measure acute stress and additional tools were included to support the health care workforce. This instrument has been used in several Latin American countries and has been adapted considering cultural differences. The resources section of the website was the most visited with 18,516 out of 68,913 (26.9%) visits, and the “Self-Report Acute Stress Scale” was the most visited resource with 6468 out of 18,516 (34.9%) visits.

Conclusions

The Be + against COVID platform (website and app) was developed and launched to offer a pool of recommendations and support resources, which were specifically designed to protect the psychological well-being and the work morale of health care workers. This is an original initiative different from the usual psychological assistance hotlines.

Prevention of accidental exposure in radiotherapy: the risk matrix approach

Knowledge and lessons from past accidental exposures in radiotherapy are very helpful in finding safety provisions to prevent recurrence. Disseminating lessons is necessary but not sufficient. There may be additional latent risks for other accidental exposures, which have not been reported or have not occurred, but are possible and may occur in the future if not identified, analyzed, and prevented by safety provisions. Proactive methods are available for anticipating and quantifying risk from potential event sequences. In this work, proactive methods, successfully used in industry, have been adapted and used in radiotherapy. Risk matrix is a tool that can be used in individual hospitals to classify event sequences in levels of risk. As with any anticipative method, the risk matrix involves a systematic search for potential risks; that is, any situation that can cause an accidental exposure. The method contributes new insights: The application of the risk matrix approach has identified that another group of less catastrophic but still severe single-patient events may have a higher probability, resulting in higher risk. The use of the risk matrix approach for safety assessment in individual hospitals would provide an opportunity for self-evaluation and managing the safety measures that are most suitable to the hospital's own conditions.

Fast Monte Carlo simulation on a voxelized human phantom deformed to a patient

PURPOSE

A method for performing fast simulations of absorbed dose using a patient's computerized tomography (CT) scan without explicitly relying on a calibration curve is presented.

METHODS

The method is based on geometrical deformations performed on a standard voxelized human phantom. This involves spatially transforming the human phantom to align it with the patient CT image. Since the chemical composition and density of each voxel are given in the phantom data, a calibration curve is not used in the proposed method. For this study, the Monte Carlo (MC) code PENELOPE has been used as the simulation of reference. The results obtained with PENELOPE simulations are compared to those obtained with PENFAST and with the collapsed cone convolution algorithm implemented in a commercial treatment planning system.

RESULTS

The comparisons of the absorbed doses calculated with the different algorithms on two patient CTs and the corresponding deformed phantoms show a maximum distance to agreement of 2 mm, and in general, the obtained absorbed dose distributions are compatible within the reached statistical uncertainty. The validity of the deformation method for a broad range of patients is shown using MC simulations in random density phantoms. A PENFAST simulation of a 6 MV photon beam impinging on a patient CT reaches 2% statistical uncertainty in the absorbed dose, in a 0.1 cm3 voxel along the central axis, in 10 min running on a single core of a 2.8 GHz CPU.

CONCLUSIONS

The proposed method of the absorbed dose calculation in a deformed voxelized phantom allows for dosimetric studies in the geometry of a patient CT scan. This is due to the fact that the chemical composition and material density of the phantom are known. Furthermore, simulation using the phantom geometry can provide dosimetric information for each organ. The method can be used for quality assurance procedures. In relation to PENFAST, it is shown that a purely condensed-history algorithm (class I) can be used for absorbed dose estimation in patient CTs.

Triunism: a transmaterial train--mind theory

Triunism postulates that the mind is a unity with the following three structural elements so essential that the absence of any one will prevent its existence: (1) Brain cells and pathways possessing material and transmaterial properties. (2) A flow of environmental information, coded and transduced at the sensory receptors and forming part of the working brain through modifications of its anatomy and physiology. (3) Detectable manifestations derived from (1) and (2) which are expressed inward as perceptions and outward as behaviour. The outside world enters through the senses and becomes a material and functional part of the maturing brain. Without a brain, the mind cannot exist. Without sensory inputs, the mind will not be structured and cannot appear. Without manifestations of inner perceptions and outward motor expression, the mind cannot be recognized by the individual or the environment. Transmaterial entities require the existence of supporting matter and may be represented by patterns of material organization or by temporal or functional relations between parts of the material substratum. They may transcend the existence of specific materials, changing carriers while preserving their nonmaterial identity, but do not possess intrinsic properties of matter such as mass and energy. Transmaterial aspects of reality, including material substratum patterning, and relative temporal, and functional characteristics may be subjects of experimental research.

Endobronchial brachytherapy in the treatment of malignant lung tumours

A prospective study was made to assess the short-term clinical and endoscopic response to high-dose-rate endobronchial brachytherapy (HDREB) in patients with malignant endobronchial tumours. From July 1995 to May 2000, 288 HDREB sessions were carried out on 81 patients. The mean patient age was 61.57 yrs (range 34-82); males were predominant (87.65%). Tumours were primary in 76 patients (93.82%) and metastatic in five patients (6.18%). The inclusion criteria were malignant endobronchial tumour and either palliative treatment for incurable disease or intent-to-cure treatment for residual malignancy on the bronchial resection surface after surgery or an inoperable tumour. The exclusion criteria were as follows: impediments to catheter placement, expected survival <2 months, Karnofsky index <60, or absence of informed consent. The clinical response of a symptom was categorised as complete (disappearance of the symptom), partial (less than complete) or absent. The endoscopic response was considered to be complete if lesions disappeared and biopsy findings remained negative 1 month after the last radiation session; partial if lesions improved to some extent, but the biopsy findings were positive; and absent if there was no change in relation to baseline. The technique consisted of delivering high-dose irradiation from an Ir192 source to a target volume using one or two endobronchial catheters inserted under optical or video bronchoscopic guidance. Four sessions were scheduled at weekly intervals and 500 cGy was applied per session over a length of 1-9 cm, measured 0.5-1 cm from the centre of the source. In total, 85% of the symptoms analysed (haemoptysis, cough, dyspnoea, expectoration, and stridor) disappeared with HDREB, which was categorised as a complete response. The endoscopic response was complete in 56.79% of patients, partial or less than complete in 40.74% and absent in 2.46%. One major complication occurred (bronchial fistula 1.2%), but no lethal haemoptysis. Minor complications (pneumonitis, bronchospasm and bronchial stenosis) each occurred in one patient (1.2%). High-dose-rate endobronchial brachytherapy is a good palliative treatment for endoluminal lung neoplasms, effectively alleviating symptoms and endoscopic evidence in many cases with an acceptable rate of complications. High-dose-rate endobronchial brachytherapy can be carried out as an intent-to-cure procedure in highly selected cases.

Effects of arsenite on central monoamines and plasmatic levels of adrenocorticotropic hormone (ACTH) in mice

We studied the effects of chronic arsenic exposure on brain monoamines and plasma levels of adrenocorticotropic hormone (ACTH) of mice. After weaning, mice received arsenic (0, 20, 40, 60 or 100 ppm) in drinking water over a period of 9 weeks. Monoamine content was quantified in different brain regions, arsenic was quantified in brain tissue and ACTH levels in plasma. Brain arsenic concentrations up to 200 ng/g showed a significant correlation with exposure levels and produced slight modifications in regional monoamine levels. ACTH plasma levels were significantly associated with norepinephrine (NE) concentrations in the medulla and pons, but not with hypothalamic NE levels. ACTH levels were significantly higher in the group exposed to 20 ppm. Dopamine showed significant dose-related decreases in the hypothalamus. These results show that chronic sodium arsenite exposure produces changes in central monoamines, which are not associated on a dose-dependent basis with major alterations in plasma ACTH.

Neuronal imprinting of human values

In the 21st century, psychophysiology will face the challenge of establishing ethical principles and practical means for the genetic and social influencing of the development of human beings. Neuronal imprinting of beliefs and morality within infantile minds will be necessary for the peaceful coexistence of races and cultures. This process requires study and consideration, among others, of the following psychophysiological facts: (1) Genes do not transmit moral values. (2) Material support of physiological activities is necessary for the existence and development of mental functions. (3) Imprinting of human values is based on material changes within neuronal structures. (4) Early neuronal imprinting is performed without personal awareness or consent of the individual and depends on sensory inputs, mainly from the social structure of the group. (5) Biological structures lack values. Personal and social antagonisms do not depend on genes, but on cultural indoctrination. (6) Pleasure and punishment (positive and negative reinforcement) are the two main elements, which regulate animal and human behavior. (7) Values must be chosen by adults, who decide the questions 'why'? 'when'? 'which ones'?, 'who should teach'?, 'what?' and 'how'? (8) Many biological imperatives are shared by all animals and by all people. Human beings may be considered the 'crickets of the Universe', unable to understand the mysteries of nature because of our insufficient neuronal capacity. (9) Our emotional life is mainly related to the structure of the limbic system controlled by the neocortex. (10) New theories based on the integration of physics, chemistry, biology and other specific areas of knowledge, as proposed by the General Theory of Systems, will avoid 'opposites', favoring the acceptance of complementary aspects of reality. (11) Early education will promote preferential learning which depends on both genetic endowment and neuronal development influenced by experience. It is the responsibility of psychophysiology to establish the guidelines for better education, clarifying the material and psychological aspects of the mind.

Exact analytical solution of the convolution integral equation for a general profile fitting function and Gaussian detector kernel

One of the most important aspects in the metrology of radiation fields is the problem of the measurement of dose profiles in regions where the dose gradient is large. In such zones, the 'detector size effect' may produce experimental measurements that do not correspond to reality. Mathematically it can be proved, under some general assumptions of spatial linearity, that the disturbance induced in the measurement by the effect of the finite size of the detector is equal to the convolution of the real profile with a representative kernel of the detector. In this work the exact relation between the measured profile and the real profile is shown, through the analytical resolution of the integral equation for a general type of profile fitting function using Gaussian convolution kernels.

Cloning and sequence analysis of the gene encoding invertase (INV1) from the yeast Candida utilis

The gene INV1 encoding invertase from the yeast Candida utilis has been cloned using a homologous PCR hybridization probe, amplified with two sets of degenerate primers designed considering sequence comparisons between yeast invertases. The cloned gene was sequenced and found to encode a polypeptide of 533 amino acids that contain a 26 amino-acid signal peptide and 12 potential N-glycosylation sites. The nucleotide sequences of the 5' and 3' non-coding regions were found to contain motifs probably involved in initiation, regulation and termination of gene transcription. The amino-acid sequence shows significant identity with other yeast, bacterial and plant beta-fructofuranosidases. The INV1 gene from C. utilis was able to complement functionally the suc2 mutation of S. cerevisiae.

Modelling the kinetics of antigen-antibody reactions at particle enhanced optical immunoassays

Functionalized latexes coated by antibodies are used in diagnostic tests for the detection of antigens in biological fluids. A simple kinetic model is presented which is related to the optical monitoring of the formation of specific complexes between antigen and antibody amplified by latex beads. The antibodies are chemically coupled onto chloromethylstyrene (CMST) particles. The kinetic model is able to describe the immunoprecipitin curves of immunolatex beads. The number of fitting parameters is relatively reduced (only three), and the meaning of these parameters can be interpreted in terms of the chemical equilibrium constant, the percentage of active IgG on the latex beads, and optical response. The model explains very well the optical response of immunolatex prepared by covalent coupling of antibodies on polymer carriers.

Development of an integrative DNA transformation system for the yeast Candida utilis

We report here the development of an auxotrophic transformation system for the food yeast Candida utilis. To facilitate molecular studies in Candida utilis, we isolated auxotrophic strains for uracil biosynthesis by the combination of NTG-mutagenesis and 5-fluorotic acid (FOA) selection. The ura-mutation could be functionally complemented by the homologous URA3 gene. We used both, LiAc and electroporation methods to direct insertions at the ura3 locus through homologous recombination.

Stereotactic radiosurgery with linear accelerator

Stereotactic radiosurgery is a method that applies a radiation dose to a limited and well-defined volume while the irradiation of adjacent healthy tissues is minimized. It is most commonly used in the treatment of intracranial lesions because the skull hardness assures the stable location of its contents. Treatment of the rest of the body has recently been proposed and carried out, using original immobilization systems. Stereotactic radiosurgery was first described in 1951 by the Swedish neurosurgeon Lars Leksell who originally used X-rays and then high-energy protons as a source of radiation. In the '80s photons from linear accelerators were used as radiation source, with various stereotactic systems and computerized treatment planning. The method used with all radiosurgical systems, regardless of the source of irradiation, is similar. The lesion is detected with common diagnostic imaging and adequate location frames. At present, to prevent errors in location, MRI and CT data are matched using an Image Fusion computer program. The objective of stereotactic radiosurgery is to destroy tumor cells or to induce changes in tissues that, as in brain arteriovenous malformations lead to the occlusion of their abnormal vessels. Stereotactic radiosurgery is increasingly used today in the treatment of a variety of intracranial lesions to the patients' benefit.

Experimental determination of the convolution kernel for the study of the spatial response of a detector

One of the most important parameters in the characterization of a detector is its spatial convolution kernel. This kernel contains all of the information about the influence that the detector size has on the measured beam profile. In this paper we present an experimental method for the determination of the spatial convolution kernel for commonly used detectors that are employed in the x-ray profile measurement: film + densitometer, diode, and ionization minichamber. Our work is based on first assuming a step function pattern on a photographic film is known and is a perfect step function. The kernel of the densitometer system was then derived from the deconvolution of the scanned profile to the step function. Next a film was exposed to a penumbra area of an x-ray beam from a linac. The film was scanned using the same densitometer. The "real profile" that emerges from a linear accelerator was derived by the deconvolution of the scanned profile using the now known kernel of the film densitometer. Under the same irradiation condition the x-ray profile was measured with other detectors and with this information we obtained the convolution kernels for these detectors by solving numerically their basic convolution integrals. The results show that the Gaussian convolution kernel is the most consistent with the measurements. The best numerical values for the FWHM of the kernels are 1.1 mm, 2.2 mm, and 5.4 mm for densitometer, diode, and minichamber, respectively.

Purification and characterization of an invertase from Candida utilis: comparison with natural and recombinant yeast invertases

A periplasmic invertase from the yeast Candida utilis was purified to homogeneity from cells fully derepressed for invertase synthesis. The enzyme was purified by successive Sephacryl S-300, and affinity chromatography and shown to be a dimeric glycoprotein composed of two identical monomer subunits with an apparent molecular mass of 150 kDa. After EndoH treatment, the deglycosylated protein showed an apparent molecular weight of 60 kDa. The apparent K(m) values for sucrose and raffinose were 11 and 150 mM, respectively, similar to those reported in Saccharomyces cerevisiae. The range of optimum temperature was 60-75 degrees C. The optimum pH was 5.5 and the enzyme was stable over pH range 3-6.

Invertase secretion in Hansenula polymorpha under the AOX1 promoter from Pichia pastoris

A DNA fragment containing a transcription regulating region of the alcohol oxidase (AOX1) gene from the methylotrophic yeast Pichia pastoris was used in the construction of a vector for the expression of heterologous proteins in the methylotrophic yeast Hansenula polymorpha. We used this vector to clone the SUC2 gene from Saccharomyces cerevisiae into H. polymorpha yeast. The culture conditions for invertase production using a fed-batch culture were studied. More than 1.5 x 10(3) U/ml of biologically active invertase (1 g/l) were secreted to the cellular periplasmic space. The fermentative process was scaled up to 50 l. Invertase produced from H. polymorpha was glycosylated, but it contained significantly less carbohydrate than protein produced by S. cerevisiae. Using the Western-blot technique, it was observed that invertase secreted from H. polymorpha and invertase secreted from S. cerevisiae showed common antigenic determinants.

Isolation and characterization of mutants as an approach to a transformation system in Kluyveromyces marxianus

A method to obtain K. marxianus mutants has been developed. Different auxotrophic mutants were isolated by nystatin and snail-enzyme enrichment procedures using an incubation time of 2 h before adding the antibiotic or the enzyme respectively. All his mutants analyzed by complementation tests turned out to belong to the same complementation group. Some of them were transformed and complemented by the S. cerevisiae HIS3 gene. These non-reverting his3 mutants contain no heterologous sequence, which is essential to make them acceptable for application in the food industry.

Intraoperative radiation therapy in malignant glioma: early clinical results

Intraoperative radiation therapy (IORT) with high energy electron beams is a treatment modality that has been included in multimodal programs in oncology to improve local tumor control. From August 1991 to December 1993, 17 patients with primary (8) or recurrent (9) high grade malignant gliomas, anaplastic astrocytoma (4), anaplastic oligodendroglioma (6) and glioblastoma multiforme (7), underwent surgical resection and a single dose of 10-20 Gy intraoperative radiation therapy was delivered in tumor bed. Fourteen patients received either pre-operative (8) or post-operative (6) external beam radiation therapy. Primary gliomas: 18-months actuarial survival rate has been 56% (range: 1-21+ months) and the median survival time has not yet been achieved. Four patients developed tumor progression (median time to tumor progression: 9 months). Recurrent gliomas: 18-months actuarial survival rate and median survival time has been 47% and 13 months (range: 6-32+ months) respectively. The median time to tumor progression was 11 months. No IORT related mortality has been observed. IORT is an attractive, tolerable and feasible treatment modality as antitumoral intensification procedure in high grade malignant gliomas.

[The assessment of neurological care needs in the health sector of de San Juan de Alicante by key-informants model]

BACKGROUND

Specific health care planning should be based on the care request according the most adjusted evaluations method. Data obtained from each geographic area may be most comparable with other from close areas.

AIM

To determinate the neurological needs in the health area 16 of Valencian Community that includes the care corresponding to Hospital of San Juan de Alicante.

MATERIAL AND METHOD

We conducted a survey among key informants using the primary care physicians of the area. The population of the healthy area is 144,781 people and includes 78 primary care physicians. We used the formula proposed by Kurtzke in 1982 in order to calculate the neurological time.

RESULTS

We obtain a response rate of 82% the total number of neurological hours requested was 5,823.84 hours by year, which supposes a need of 8.82 neurologists by 100,000 people and nears a needs of 12.77 neurologists for the healthy area. These data are clearly higher that the obtained in other close areas using the same methodology (5 neurologists by 100,000 inh in Alcoi, 6 neurologists by 100,000 inh in the area corresponding to General Hospital of Alicante). The topics that require more than 100 hours by year are: migraine (1,205), lumbar backache (1,104), alcoholism (762), cranial trauma (442), deafness (285), stroke (272), seizures (181), disk herniation (166), cervical backache (140), zoster (162), psychosis (118), which supposes 83.12% of the whole neurological time.

CONCLUSIONS

The data situated the area within a model of direct neurological care similar to that in the United States.

[Neurological education of general practitioners. Results of a survey carried out among 196 general practitioners]

We have carried out a survey among professional general practitioners in our province with the aim of getting to know their opinion concerning their own training in Neurology. The survey included questions about the adequacy of training, the nature of any deficiency therein (be it theoretical and/or practical) and ability to analyse and attend a neurological patient. The percentage of replies was 78% out of a total of 196 surveys. 78.8% of those questioned consider that their neurological training has not been sufficient either for clinical or general practice; while 43.8% believe that this insufficiency is due to a lack of practical training, 1.8% think the fault lies in a lack of theoretical training, and 54.32% consider that it is due to a lack of both practical and theorectical training. 61.2% of those questioned claim to have difficulties with neurological explorations, and 55.6% claim they have greater difficulties attending a neurological patient than other patients classified within other internal medical specialties. 76% consider that it is either partially or totally false to claim that these difficulties are unimportant due to the lack of treatment for neurological illnesses, although 69.4% consider it to be partially or totally true that they will never be able to achieve diagnosis of a neurological patient due to a lack of the required complementary investigations. 43.9% consider that continued training in Neurology is not useful because it is a repetition of training received at university. As a consequence, there is an imbalance between neurological training and the need to attend the patient at the level of general practice, which should be set right by making the theoretical training given during graduation more suitable, and by increasing and improving practical credits.

Efficient expression and secretion of recombinant alpha amylase in Pichia pastoris using two different signal sequences

We have cloned and expressed a bacterial thermostable alpha amylase gene in Pichia pastoris using the methanol-controlled alcohol oxidase (AOX1) promoter. Two integrative vectors were constructed with two different secretion signal sequences in order to obtain efficient secretion of the protein. One vector contains the structural gene encoding the mature alpha amylase fused to the SUC2 gene signal sequence from Saccharomyces cerevisiae. In the other vector, the alpha amylase is expressed with its own signal sequence. In both cases, the alpha amylase were secreted into the culture medium with high efficiency, around 2.5 and 0.9 g/l respectively.

Diffuse nodular regenerative hyperplasia of the liver associated with human immunodeficiency virus and visceral leishmaniasis

We present a patient with human immunodeficiency virus (HIV) infection coincident with diffuse nodular regenerative hyperplasia (DNRH) of the liver and visceral leishmaniasis. This association has not been previously described. Some DNRH cases are secondary to irregular blood flow in the liver. In the presently described case, there exist two possible conditioning factors for heterogeneous distribution of blood flow: 1) the increased blood flow from splenomegaly, and 2) the irregular circulation of blood through sinusoids infiltrated by Leishmania-parasitized hyperplastic macrophages.

Cardiovascular reflexes in patients with malignant disease

Although some authors have reported clinical features of autonomic dysfunction in patients with malignant disease only a few systematic studies have been carried out. We have investigated the autonomic function of 48 patients with carcinoma or lymphoma by testing their cardiovascular reflexes, and compared their results with those of 62 healthy volunteers. Our patients showed a smaller increase in heart rate and a greater fall in blood pressure on standing up, as well as a smaller rise in blood pressure in response to contralateral handgrip. The study group showed a higher percentage of established sympathetic lesion (54.2% vs 27.4%, p: 0.008) and of atypical pattern of global autonomic function impairment (50% vs 24.2%, p: 0.03) than the control group. Our data suggest that patients with malignant disease suffer from a definite autonomic dysfunction.

Neurosecretory and trophic action on fetal rat neuroblasts induced by an amino acid mixture

The effects of a synthetically obtained mixture of amino acids (FACE) were investigated on the trophic and neurosecretory activity of in vitro cultures of fetal rat neuronal cells. The addition of 10(-6) M FACE to the culture medium significantly increased cell DNA content. Secretions of IR-SRIF, IR-VIP, and IR-GRF were also augmented in different proportions by the presence of FACE. Time studies demonstrated that IR-SRIF was significantly increased after 48 (P less than 0.05) and 72 (P less than 0.01) hr of exposure to FACE, and IR-VIP secretion was potentiated after only 24 hr of culture. Dose-response experiments with 10(-7) to 10(-4) M FACE indicated that concentrations of 10(-5) and 10(-4) M significantly increased both somatostatin released to the medium and cell content of IR-SRIF. FACE concentrations as low as 10(-10) M augmented the secretion of IR-GRF, and there was a dose-response correlation between 10(-10) and 10(-5) M FACE. The release and cell content of IR-VIP were also increased by FACE, with a dose-response relation at concentrations of 10(-9) to 10(-6) M. It can thus be concluded that FACE has a powerful effect on the multiplication and survival of fetal cerebrocortical cells and is also an important potentiator of IR-SRIF, IR-VIP, and IR-GRF secretion.

Secretions of somatostatin and VIP in cultures of fetal rat neuroblasts increased by amino acids

Neuroblasts obtained from 17 day old rat embryos were incubated for 8 days, after which half of them were treated with 10(-6) M FACE (a mixture of amino acids high in glycine, alanine and aspartic acid), and the other half were left as controls. At the end of 20 days, levels of somatostatin (SRIF) were over 6,000 pg/plate in neuroblasts treated with FACE, versus 500 pg/plate in controls. At this time vasoactive intestinal peptide (VIP) levels were over 230 pg/plate in the FACE treated cultures, while their controls contained less than 150 pp/plate. Protein totals were similar (about 1,000 micrograms/plate) in all FACE treated cultures and controls, indicating that increases in SRIF and VIP were not determined by changes in cell population, but by their synthetic and/or secretory activities triggered by minute amounts of FACE. These results may be of interest in the understanding of Alzheimer's disease.

Temporal profile of levels of monoamines and their metabolites in striata of rats implanted with dialysis tubes

We have measured the levels of monoamines and their metabolites in rat striata implanted with a dialysis tube, in contralateral nonimplanted striata, and in dialysates obtained from the dialysis tube. The perfusion was done with Ringer solution. The animals were perfused either for a continuous period of 7 h at 1 day after implantation or for periods of 2 h on days 1, 4, and 7 after implantation. In animals perfused for 7 h, levels of monoamine metabolites in dialysates remained stable for the first 4 h of perfusion, but a reduction was observed during the last 3 h. In animals perfused for 2 h on days 1, 4, and 7 after implantation, we observed a progressive reduction in levels of metabolites in dialysates with respect to the first day of perfusion. The levels of dopamine and its metabolites in the striata in which a dialysis cannula had been implanted showed a progressive reduction during the period postimplantation comparable to that observed in dialysates. The levels of 3-methoxytyramine, 3,4-dihydroxyphenylacetic acid, and homovanillic acid were elevated 24 h after implantation in the implanted striata with respect to the contralateral nonimplanted striata, but 7 days after implantation, the levels of dopamine were decreased in the implanted striata, and the levels of metabolites were unchanged.

Aminobutyric acid greatly increases the in vivo extracellular taurine in the rat hippocampus

The effects of gamma-aminobutyric acid (GABA) on the extracellular levels of taurine and on excitability in the dentate gyrus were studied in anesthetized rats by the dialytrode technique. The dentate gyrus was perfused by means of a dialytrode with Krebs-Ringer-bicarbonate or GABA solutions. Amino acid contents in perfusates and dentate field potentials evoked by electrical stimulation of the perforant pathway were evaluated. GABA drastically elevated the levels of extracellular taurine in a dose-dependent manner, decreasing the amplitude of the population spike. This result indicates that GABA stimulates taurine release, probably by a counter-transport process. It is suggested that in physiological conditions an increase in extracellular taurine may be produced by synaptically released GABA.

Dialytrode technology and local profiles of amino acids in the awake cat brain

Methods to investigate the in vivo effects and release of neuroactive substances include cortical cups, push-pull cannulae, chemitrodes, and dialytrodes. Critical evaluation of these procedures is necessary in order to interpret related results and to select the most suitable devices for further studies. Recent improvements in the dialytrode include structural modifications and the use of a small, permeable membrane constructed of thin polyester. The dialytrode system and its diffusion rates have been characterized with in vitro studies. In vivo long-term experiments in awake cats have been conducted to test injection rates, diffusion of [14C]urea, temporal variability, pressure factors, and other experimental variables. Using dialytrodes we have measured the normal profile of amino acids present in different cerebral structures and their possible correlations.

Pulse shape of magnetic fields influences chick embryogenesis

A total of 295 chick embryos was exposed during the first 48 hours of development to pulsed electromagnetic fields of 100 Hz and 0.4 to 104 microTeslas (micro T), and findings were compared with those in 364 control embryos. General morphology was analysed and supplemented by light microscopy studies. Exposure to electromagnetic fields with a pulse rise time of 100 microseconds produced teratogenic changes when intensities of 1.0 and 13.9 micro T were used but not with lower or higher intensities, demonstrating a 'window' effect and ruling out the possible influence of a rise in internal embryonic temperature. Exposure to an electromagnetic field of 1.0 micro T specifically altered organogenesis of the truncal nervous system and drastically reduced the alcian blue-stained components, whereas with an intensity of 13.9 micro T, there were abnormalities in the circulatory system and foregut, altering cell-to-cell contacts in the walls of developing vessels. When embryos were exposed to intensities of 0.4 and 1.0 micro T with 2.0 and 42 microseconds pulse rise times, teratogenic effects were greater and alterations involved all developing systems. The most powerful effects were obtained with 1.0 micro T and 42 microseconds rise time. The findings confirm the sensitivity of chick embryos to electromagnetic fields of extremely low frequency and intensity and indicate that pulse shape may be a decisive parameter determining strong, slight, or no modification of embryonic development. Mechanisms of action of electromagnetic fields are still unclear, but induced alterations in extracellular glycosaminoglycans could be a causal factor in the observed malformations.

Periaqueductal gray inhibition of trigeminal subnucleus caudalis unitary responses evoked by dentine and nonnoxious facial stimulation

The possible pain inhibitory effects of periaqueductal gray (PAG) stimulation were investigated in cats anesthetized with Nembutal and immobilized with Flaxedil. Unitary responses evoked by electrical stimulation of the upper canine dentine and by cutaneous facial noxious and nonnoxious stimuli were recorded extracellularly from the trigeminal subnucleus caudalis. A bipolar electrode was introduced into the PAG to test the effects of PAG excitation on the trigeminal response to dentine (TRED) and cutaneous nonnoxious stimulation. In some experiments, a similar electrode was lowered into the contralateral posterior thalamus to study the antidromic activation of subnucleus caudalis cells and the effects of thalamic stimulation on the TRED. Dentine stimulation evoked brief (6- to 15-ms) bursts of 1 to 10 spikes with 3- to 25-ms latencies. Most units (88%) were also activated by cutaneous facial stimulation. Stimulation of the posterior thalamus had no effect on the TRED or on responses to cutaneous stimulation, but activated antidromically 10% of the units. In 71% of the units PAG stimulation inhibited the TRED. In some of those cases (12%), the inhibitory effect persisted 30- to 60 s. The PAG stimulation could produce paradoxical effects, potentiating the TRED evoked by threshold intensity and inhibiting the TRED elicited by suprathreshold stimulation. About one-half the PAG points evoked detectable effects. Their location had no clear topographical distribution, although ventral sites were more potent than dorsal sites. Responses evoked by nonnoxious facial stimulation were also inhibited by the PAG.

Aspartate kinase and homoserine dehydrogenase of Candida utilis

Aspartate kinase and homoserine dehydrogenase activity were assayed in a dialyzed cell-free extract of Candida utilis. Aspartate kinase was partly inhibited by ATP-Mg and by Mg2+ alone. There appear to be two isoenzymes of aspartate kinase in the yeast, one heat-labile, the other relatively heat-stable. The first is subject to feedback inhibition by threonine, the other is threonine-resistant. Neither aspartate kinase nor homoserine dehydrogenase is the rate-limiting enzyme in methionine biosynthesis. Homoserine dehydrogenase measured in the forward direction showed an activity five times higher than aspartate kinase. No regulatory interaction could be demonstrated for this enzyme. No repression of aspartate kinase and homoserine dehydrogenase synthesis by threonine, methionine or both amino acids was observed.

Oviposition and development of Drosophila modified by magnetic fields

Drosophila flies placed in a habitat with two lateral boxes demonstrated sensitivity to magnetic fields: Oviposition decreased by exposure to pulsated (extremely low frequency (ELF) (100 Hz, 1.76 miliTesla (mT) ) and sinusosidal fields (50 Hz, 1 mT), while there was no initial effect of exposure to a static magnetic field (4.5 mT). Drosophila eggs treated for 48 h with the above described fields showed that 1) mortality of eggs was lower in controls than in eggs exposed to all tested magnetic fields; 2) mortality of larvae increased when a permanent magnet was used; 3) mortality of pupae was highest when a permanent magnet was used; and 4) general adult viability was highest in controls (67%) and diminished progressively when eggs were exposed to pulsated (55%), sinusoidal (45%), and static (35%) magnetic fields.

Embryological changes induced by weak, extremely low frequency electromagnetic fields

Fertilized chicken eggs were incubated for 48 hours while exposed to extremely low frequency magnetic fields (ELMF) of 10 Hz, 100 Hz and 1000 Hz with intensities of 0.12, 1.2 and 12 micro T. Gross morphological and histological analysis of the exposed embryos revealed the following effects: (1) ELMF of 100 Hz/1.2 micro T had the most consistent and powerful inhibitory effect on embryogenesis. Development of embryos was reduced to the formation of the three primitive layers. Brain vesicles, auditory pit, neural tube, foregut, heart, vessels, and somites were not developed. Glycosaminoglycans were almost absent. (2) The above results demonstrate a window effect because embryos exposed to 100 Hz/1.2 micro T were less developed than embryos exposed at lower and higher intensities and frequencies. (3) Developing organs reacted with different sensitivity to ELMF of specific frequencies and intensities. Somites were not disturbed by exposure to 10 Hz with any of the intensities used. Formation of blood vessels was completely blocked by ELMF of 1000 Hz/12 micro T while traces of other organs were present. (4) The drastic embryological disturbances described were obtained with much lower intensities (1 micro T = 0.01 Gauss) than those used in studies by other investigators. (5) Embryological alterations induced by ELMF may depend on disturbances in the presence and structure of glycosaminoglycans which are essential elements in cellular activities, including cell migration. (6) The use of ELMF of low intensity may be a powerful method to investigate embryogenetic mechanisms and may also be a useful technique for investigation of other biological systems.

Methionine-defective mutants in Candida utilis

Ethionine-resistant mutants of Candida utilis CCY-158 overproducing methionine have been isolated. In these mutants the intracellular methionine concentration decreased significantly during the stationary phase. The wild-type strain CCY-158 and the ethionine-resistant mutants isolated were able to use methionine as the nitrogen source but not as the carbon source. From these ethionine-resistant mutants we isolated mutants unable to use methionine as nitrogen source (Mec- mutants), the principal alteration being at the level of methionine uptake. Some of the Mec mutants lost also the ability to use other amino acids as nitrogen source.

Optimization on the selection of auxotrophic mutants in Candida utilis by snail enzyme treatment

The determination of the best conditions for the application of the snaill enzyme digestion method in the enrichment of auxotrophic mutants in Candida utilis was carried out following Box and Wilson's mathematical method. The selection procedure proposed was tested in the enrichment of auxotrophic mutants from a mutagenized culture of a wild-type strain. Mutant frequency was increased 46-fold by treatment with snail enzyme. The method also proved useful in the selection of additional auxotrophic mutations from single auxotrophs.

Nocturnal and diurnal sleep in Macaca sylvana

In Macaca sylvana restrained in chairs, continuous 24 h recordings were obtained of scalp EEG, neck EMG, bilateral EOG, motility of the head and lever manipulation. A total of 32 days were studied in 8 monkeys. Recordings were divided into epochs of 30 sec and analyzed in a PDP-12 computer. Four stages of sleep and 5 stages of wakefulness were identified by combination of the above data. Results were as follows: (1) During the night, there was 21% wakefulness and during the day 20% sleep, including a considerable amount of REM. (2) Recordings of spontaneous motility of head and hands proved an excellent indicator of sleep-wakefulness cycles. (3) Spectral analysis revealed the cyclic characteristics of non-REM sleep, with peaks at 360, 149, 72, and 55 min. (4) Stages of wakefulness had ultradian cycles, and stage W-2 was the most important in number and duration of occurrences. (5) Night wakefulness had characteristics different from day wakefulness. (6) Study of sequences showed that stage II was the least differentiated being transitional among the other stages, while stage III-IV was never preceded by wakefulness or REM, and almost always it followed stage II (99.0% of the time). (7) The high statistical significance of results obtained under restraint in different monkeys suggests that this situation has great potential value in the investigation of physiological mechanisms of ultradian rhythms.

Cerebral blood flow and behavior during brain stimulation in the goat

Cerebral blood flow, heart rate, arterial blood pressure, and behavior were studied in conscious goats during electrical stimulation of the diencephalon and mesencephalon. Stimulation of the subthalamic area produced a considerable increase in ipsilateral cerebral blood flow and heart rate, accompanied by either a small or a large increase in systemic arterial blood pressure. Cardiovascular effects were associated with changes in alertness. The increase in cerebral blood flow was partially abolished by previous administration of atropine directly into the internal maxillary artery. Stimulation of the mesencephalic reticular formation caused a marked increase in blood pressure with no change or with some decrease in cerebral blood flow. After administration of phentolamine into the internal maxillary artery, stimulation produced increase in cerebral blood flow. The behavioral response consisted of restlessness and attempted flight. These results suggest the existence of cholinergic vasodilator and adrenergic vasoconstrictor pathways to cerebral blood vessels that may be stimulated electrically.

Instrumentation, working hypotheses, and clinical aspects of neurostimulation

The paper describes instrumentation developed in our laboratory for the therapy of neurological disorders, including (a) hybrid stimulator for chronic use which retains constant current characteristics, providing a low resistance path during the quiescent phase between pulses to minimize the postpulse charge; (b) brain radio stimulators, crystal controlled, with digital logic section and an optoelectric sensor for telemetry of the intensity used; (c) external stimoceiver for experimental and clinical use, combining multichannel stimulator and EEG telemetric instrument; (d) transdermal stimoceivers, totally implantable for two-way communication with the brain through the intact skin; and (e) implantable microprocessor for detection of EEG signals which are used to trigger contingent brain stimulation. Our working hypotheses for chronic brain stimulation include (a) electrical modification of the functional set point of specific cerebral areas; (b) feedback-controlled stimulation; and (c) establishment of artificial neuronal links with the aide of the computer. The paper concludes with a discussion of the indications for therapeutic use of brain stimulation and criteria for patient selection.

Neurobiology of aggressive behavior

Causality, neurological mechanisms, and behavioral manifestations may be heterogeneous in different forms of aggressive behavior, but some elements are shared by all forms of violence, including the necessity of sensory inputs, the coding and decoding of information according to acquired frames of reference, and the activation of pre-established patterns of response. Understanding and prevention of violence requires a simultaneous study of its social, cultural, and economic aspects, at parity with an investigation of its neurological mechanisms. Part of the latter information may be obtained through animal experimentation, preferably in non-human primates. Feline predatory behavior has no equivalent in man, and therefore its hypothalamic representation probably does not exist in the human brain. Codes of information, frames of reference for sensory perception, axis to evaluate threats, and formulas for aggressive performance are not established genetically but must be learned individually. We are born with the capacity to learn aggressive behavior, but not with established patterns of violence. Mechanisms for fighting which are acquired by individual experience may be triggered in a similar way by sensory cues, volition, and by electrical stimulation of specific cerebral areas. In monkeys, aggressive responses may be modified by changing the hierarchical position of the stimulated animal, indicating the physiological quality of the neurological mechanisms electrically activated.

Ultradian rhythms in the mobility and behavior of rhesus monkeys

The presence of ultradian rhythms in the mobility and behavior of rhesus monkeys was explored in eleven animals equipped with mobility FM transmitters and placed alone or in pairs in laboratory cage situated in a sound proof, temperature controlled room, with food and water ad libitum. After an habituation period of 3 to 7 days, telemetric recordings of the mobility of the animals showed ultradian rhythms with a periodicity of 70 min during the daily 12-h light period. During the corresponding 12-h dark period, there were two dominant cycles of 103-144 min and 48 min respectively. Restriction of food and water to 1h/day did not change the duration of these cycles, and the presence of random noise also had little effect. Spontaneous behavior occurred in regular sequences within each cycle. Social relationships were found to affect rhythmicity of behavior, since pairs of monkeys synchronized their cycles. The lever press response recorded during auto-shaping showed the same rhythmicity found in mobility, demonstrating the influence of ultradian rhythms on learned behavior.