Showing papers by "University of California, San Francisco published in 1979"

Isolation of biologically active ribonucleic acid from sources enriched in ribonuclease.

Abstract: Intact ribonucleic acid (RNA) has been prepared from tissues rich in ribonuclease such as the rat pancreas by efficient homogenization in a 4 M solution of the potent protein denaturant guanidinium thiocyanate plus 0.1 M 2-mercaptoethanol to break protein disulfide bonds. The RNA was isolated free of protein by ethanol precipitation or by sedimentation through cesium chloride. Rat pancreas RNA obtained by these means has been used as a source for the purification of alpha-amylase messenger ribonucleic acid.

Simultaneous modeling of pharmacokinetics and pharmacodynamics: Application to d-tubocurarine

Abstract: We propose a model of drug pharmacodynamic response that when integrated with a pharmacokinetic model allows characterization of the temporal aspects of pharmacodynamics as well as the time-independent sensitivity component. The total model can accommodate extremes of effect. It allows fitting of simultaneous plasma concentration (Cp) and effect data from the initial distribution phase of drug administration, or from any non-equilibrium phase. The model postulates a hypothetical effect compartment, the dynamics of which are adjusted to reflect the temporal dynamics of drug effect. The effect compartment is modeled as an additional compartment linked to the plasma compartment by a first-order process, but whose exponential does not enter into the pharmacokinetic solution for the mass of drug in the body. The hypothetical amount of drug in the effect compartment is then related to the observed effect by the Hill equation, a nonlinear sigmoid form. Nonlinear least-squares data fitting is used for parameter estimation. The model is demonstrated on two different sets of Cp and effect data for the drug d-tubocurarine (dTC). In 7 normal subjects, the (mean +/- SD) rate constant for equilibration of dTC effect (paralysis) and Cp is 0.13 +/- 0.04 min-1 and the (mean +/- SD) steady-state Cp required to produce 50% paralysis is 0.37 +/- 0.05 microgram/ml.

An analysis of dose-effect relationship in the radiotherapy of malignant gliomas.

Abstract: The relationship between increasing survival and increasing doses of radiotherapy has been examined in 621 patients who were entered into three successive Brain Tumor Study Group protocols between 1966 and 1975. These patients were operated upon and had histologically proven malignant gliomas. The median survival of patients who received no radiotherapy was 18.0 weeks; for those who had ⪯4500 rad, it was 13.5 weeks (p = .346); those who received 5000 rad had a median survival of 28 weeks (p < .001), 5500 rad - 36.0 weeks (p < .001), and 6000 rad - 42.0 weeks (p < .001). The specific relationship between 5000 and 6000 rad indicates a 1.3 times increase in median life span associated with the higher dose (p = .004). A detailed analysis of specific factors which might have significantly biased results indicated that patients who received less than 4500 rad were not comparable to other groups of patients because they had a poorer initial performance status and a greater number died before completion of radiotherapy. Factors of importance including parameters of radiotherapy, pathology distribution, the influence of corticosteroids, and the effect of age, sex, and initial performance status were all comparable within the various other subgroups. No other treatment characteristics or selective factors which might have a direct effect on survival were identified. It was concluded that radiotherapy had a significant influence on the survival of patients with malignant glioma and that a clear-cut dose-effect relationship exists.

Multiple representations of the body within the primary somatosensory cortex of primates.

Abstract: Microelectrode mapping experiments indicate that the classical primary somatosensory cortex of monkeys consists of as many as four separate body representations rather than just one. Two complete body surface representations occupy cortical fields 3b and 1. In addition, area 2 contains an orderly representation of predominantly "deep" body tissues. Area 3a may constitute a fourth representation.

Rods and cones in the mouse retina. I. Structural analysis using light and electron microscopy

Abstract: Rods and cones of the C57BL/6J mouse retina have been examined by light and electron microscopy to distinguish the structural features of the two photoreceptor types. By light microscopy, cone nuclei are conspicuously different from rod nuclei in 1-2 micrometer plastic sections. Cone nuclei have an irregularly shaped clump of heterochromatin that appears in single sections to be one to three clumps, whereas rod nuclei are more densely stained and have one large, central clump of heterochromatin. Cone nuclei make up approximately 3% of the photoreceptor nuclei in both the central and peripheral retina at all ages examined up to 267 days. Cone nuclei are confined to the outer half of the outer nuclear layer, and more than 50% of the cone nuclei lie adjacent to the outer limiting membrane. By electron microscopy, cones in the mouse retina meet virtually every morphological criterion of mammalian cones. The outer segments are conically shaped. Many, if not all of the outer segment discs are continuous with the outer plasma membrane, whereas almost all of the rod discs are not. Cone outer segments are only about half the length of the rod outer segments, and they are contacted by long, villous pigment epithelial cell processes. The cone inner segment diameter is greater than the outer segment diameter, and the accumulation of mitochondria present at the apical end of the inner segment forms a more conspicuous ellipsoid than in rods. The internal fiber or axon of the cone is larger in diameter than that of the rod, and it terminates in a large synaptic pedicle with multiple ribbon synapses, whereas the rod terminal is a smaller spherule with only a single ribbon synaptic complex.

The origin of descending pathways in the dorsolateral funiculus of the spinal cord of the cat and rat: further studies on the anatomy of pain modulation.

Abstract: There is considerable evidence that the dorsolateral funiculus (DLF) of the spinal cord contains descending pathways critical for both opiate and brainstem stimulation-produced analgesia. To obtain a comprehensive map of brainstem neurons projecting to the spinal cord via the DLF, large injections of horseradish peroxidase (HRP) were made into the lumbosacral spinal cord of cat and rat. These injections were made caudal to midthoracic lesions which spared only a single DLF or ventral quadrant (VQ); thus only those neurons whose axons descended in the spared funiculus would be labelled. Cells with descending axons in the VQ were concentrated in the medullary nucleus raphe pallidus and obscurus, nucleus retroambiguus and in various subregions of the reticular formation including the nucleus reticularis ventralis, gigantocellularis, magnocellularis, pontis caudalis and pontis oralis. Significant numbers of neurons were also found in medial and lateral vestibular nuclei and in several presumed catecholamine-containing neurons of the dorsolateral pons. In the rat, but not in the cat, considerable numbers of cells are present in the mesencephalic reticular formation, just lateral to the periaqueductal gray. In both species, some cells were found in the paraventricular nucleus of the hypothalamus. Brainstem cells projecting in the DLF were concentrated in the nucleus raphe magnus and in the adjacent nucleus reticularis magnocellularis, ipsilateral to the spared funiculus. Significant numbers of cells were found in the dorsolateral pons, differing somewhat in their distribution from those projecting in the VQ. DLF-projecting cells were also present in the ipsilateral Edinger-Westphal nucleus and periaqueductal grey contralateral red nucleus of the midbrain and in the ipsilateral hypothalamus. Smaller projections from other sites are described. These results are discussed in terms of the differential contribution of several brainstem neuronal groups, including the serotonergic nucleus, raphe magnus, the ventromedial reticular formation of the medulla, and various catecholamine-containing neurons of the dorsolateral pontine tegmentum to the analgesia produced by opiates and electrical brain stimulation.

Subjective referral of the timing for a conscious sensory experience: a functional role for the somatosensory specific projection system in man.

Abstract: Subjective experience of a peripherally-induced sensation is found to appear without the substantial delay found for the experience of a cortically-induced sensation. To explain this finding, in relation to the putative delay of up to about 500 ms for achieving the "neuronal adequacy" required to elicit the peripherally-induced experience, a modified hypothesis is proposed: for a peripheral sensory input, (a) the primary evoked response of sensory cortex to the specific projection (lemniscal) input is associated with a process that can serve as a 'time-marker'; and (b), after delayed neuronal adequacy is achieved, there is a subjective referral of the sensory experience backwards in time so as to coincide with this initial 'time-marker'. A crucial prediction of the hypothesis was experimentally tested in human subjects using suitably implanted electrodes, and the results provide specific support for the proposal. In this, the test stimuli to medial lemniscus (LM) and to surface of somatosensory cortex (C) were arranged so that a minimum train duration of 200 ms or more was required to produce any conscious sensory experience in each case. Each such cerebral stimulus could be temporally coupled with a peripheral one (usually skin, S) that required relatively negligible stimulus duration to produce a sensation. The sensory experiences induced by LM stimuli were found to be subjectively timed as if there were no delay relative to those for S, that is, as if the subjective experience for LM was referred to the onset rather than to the end of the required stimulus duration of 200 ms or more. On the other hand, sensory experiences induced by the C stimuli, which did not excite specific projection afferents, appeared to be subjectively timed with a substantial delay relative to those for S, that is, as if the time of the subjective experience coincided roughly with the end of the minimum duration required by the C stimuli. The newly proposed functional role for the specific projection system in temporal referral would be additional to its known role in spatial referral and discrimination. A temporal discrepancy between corresponding mental and physical events, i.e., between the timing of a subjective sensory experience and the time at which the state of 'neuronal adequacy' for giving rise to this experience is achieved, would introduce a novel experimentally-based feature into the concept of psychophysiological parallelism in the mind-brain relationship.

Systems of Trauma Care: A Study of Two Counties

Abstract: Cases of motor vehicle trauma victims who died after arrival at a hospital were evaluated in both Orange County (90 cases) and in San Francisco County (92 cases), Calif. All victims in San Francisco County were brought to a single trauma center, while in Orange County they were transported to the closest receiving hospital. Approximately two thirds of the non-CNS-related deaths and one third of the CNS-related deaths in Orange County were judged by the authors as potentially preventable; only one death in San Francisco County was so judged. Trauma victims in Orange County were younger on the average, and the magnitude of their injuries was less than for victims in the San Francisco County. We suggest that survival rates for major trauma can be improved by an organized system of trauma care that includes the resources of a trauma center.

A different genetic code in human mitochondria

Abstract: Comparison of the human mitochrondrial DNA sequence of the cytochrome oxidase subunit II gene and the sequence of the corresponding beef heart protein shows that UGA is used as a tryptophan codon and not as a termination codon and suggests that AU A may be a methionine and not an isoleucine codon. The cytochrome oxidase II gene is contiguous at its 5′ end with a tRNAAsp gene and there are only 25 bases at its 3′ end before a tRNALys gene. These tRNAs are different from all other known tRNA sequences.

Human growth hormone: complementary DNA cloning and expression in bacteria

Abstract: The nucleotide sequence of a DNA complementary to human growth hormone messenger RNA was cloned; it contains 29 nucleotides in its 5' untranslated region, the 651 nucleotides coding for the prehormone, and the entire 3' untranslated region (108 nucleotides). The data reported predict the previously unknown sequence of the signal peptide of human growth hormone and, by comparison with the previously determined sequences of rat growth hormone and human chorionic somatomammotropin, strengthens the hypothesis that these genes evolved by gene duplication from a common ancestral sequence. The human growth hormone gene sequences have been linked in phase to a fragment of the trp D gene of Escherichia coli in a plasmid vehicle, and a fusion protein is synthesized at high level (approximately 3 percent of bacterial protein) under the control of the regulatory region of the trp operon. This fusion protein (70 percent of whose amino acids are coded for by the human growth hormone gene) reacts specifically with antibodies to human growth hormone and is stable in E. coli.

Systematic Trends Across the Night in Human Sleep Cycles

Abstract: The durations of successive sleep cycles, defined according to NREM (stage 2) or REM onsets, were objected to trend analysis in three groups of normal subjects and in a group of elderly patients with chronic brain syndrome (CBS). NREM sleep cycles showed consistent curvilinear trends for all groups except that the trend in children was distinguished by a lengthy first NREM cycle. REM steep cycles showed quite similar curvilinear trends for the three normal age groups with the middle two cycles being longer than the first and fourth. In the CBS patients, REM sleep cycles did not show a significant trend across the night. Real-time cycles (i.e., with time awake included) manifested trends quite similar to those excluding waking. The trends in sleep cycle durations are normative characteristics of sleep which may not be apparent on a single night. A more constant cycle was found in the CBS elderly and may indicate brain pathology. Sleep cycle trends, along with such other temporal characteristics as the decline in stage 4, may provide clues to the metabolic processes which underlie the sleep EEG. They also provide a more exact basis for investigation of hypothesized biorhythm correlates of NREM-REM cycles.

Differential origins of spinothalamic tract projections to medial and lateral thalamus in the rat.

Abstract: In an earlier study (Giesler et al., 1976), antidromically identified cells of origin of the rat spinothalamic tract (STT) were found to be widely distributed throughout the lumbar dorsal horn and intermediate gray zone (IGZ). Interestingly, it appeared that STT neurons located within the ventral dorsal horn and IGZ, which appeared to respond to stimuli delivered to subcutaneous tissue, tended to be activated only from midline thalamic structures. In contrast, STT neurons within nucleus proprius and the marginal zone, which responded to noxious and innocuous cutaneous stimuli, were activated from lateral thalamic structures. The present study has investigated this apparent dichotomy in thalamic afferents using the technique of retrograde transport of horseradish peroxidase (HRP). Single and multiple small injections of HRP were made in various thalamic regions. Tissue was reacted with diaminobenzidine (DAB) or o-dianisidine (OD). Our data provide evidence that DAB histochemistry yields a more accurate reflection of the HRP concentrations surrounding an injection site which are necessary for visible retrograde transport. On the other hand, OD was found to be the more useful technique for examining labeled spinal cord neurons. With this method, 3 to 5.3 times more STT neurons were seen and far greater morphological detail was evident. Multiple HRP infusions which filled an entire hemi-thalamus labeled large numbers of cells within the spinal extensions of the dorsal column nuclei, the lateral cervical nucleus, the ventral horns and IGZ bilaterally within C1 and C2, and the nucleus proprius and IGZ at all levels. STT neurons were also seen, but in lesser numbers within the marginal zone. Labeling in spinal segments below C3 was, with a single exception, exclusively contralateral. The lumbar enlargement was seen to contribute a greater number of STT neurons than the cervical enlargement. Injections into posterior medial thalamic structures produced bilateral labeling in the ventral horns and IGZ in upper cervical segments. Within the cervical and lumbar enlargements, labeled neurons were restricted to ventral dorsal horn and to IGZ contralaterally. With the exception of the ventral horn cells of C1 and C2 where a marked reduction in labeling occurred, more anterior medial thalamic injections produced labeling within the identical areas of the gray matter and in numbers comparable to those produced by more posterior medial thalamic injections. In contrast, injections into lateral thalamic areas yielded dense labeling within the caudal extensions of the dorsal column nuclei and lateral cervical nucleus. Labeled cells were seen in the marginal zone and nucleus proprius at all levels. Together with our earlier findings, these data suggest that the rat STT is composed of two components which vary in their cells of origin, their terminations and, very likely, their functions.

Naloxone dose dependently produces analgesia and hyperalgesia in postoperative pain

Abstract: IF endorphins modulate pain, then naloxone should affect pain behaviour even in subjects who have not received exogenous opiates. However, some naloxone studies claim a lack of effect1,2, others a hyperalgesic effect3–5, and others both hyperalgesic and analgesic effects6,7. Such discrepancies may arise from the different methods used to induce and assess pain8, and from variation in dose. We know of only one previous human study which used multiple doses of naloxone6; this indicated a dose-dependent bi-directional effect. In the present study, a clinical pain paradigm was used to generate a dose–response curve for naloxone. We report that naloxone produces analgesia at low doses and hyperalgesia at high doses.

Isolation, cloning and sequence analysis of the cDNA for the α-subunit of human chorionic gonadotropin

Abstract: A 621-base pair fragment of the cDNA for the α-subunit of human chorionic gonadotropin has been isolated by cloning in a plasmid vector, and the complete nucleotide sequence determined. The entire coding region, including the 24-amino acid pre-sequence and most of the untranslated regions, are present in the fragment.

Development of allergy in children: I. Association with virus infections

Abstract: Children born into allergic families, with two allergic parents, are at high risk of developing allergy within the first 5 years of life. In order to observe possible external factors in the sensitization process, a prospective study of 13 such children was done, in which serial clinical and immunologic observations were made at 3- to 6-month intervals over a period of 1 to 4 yr. Eleven of these children are now clinically allergic; 5 have asthma. Immunologic evidence for allergic sensitization was observed in these 11 children by RAST, antigen-induced leukocyte histamine release, lymphoblastogenesis, and rise in serum IgE. Upper respiratory infections (URI) occurred in these 11 allergic children 1 to 2 months prior to the onset of allergic sensitization. In 10 of these 11 URI children, complement-fixing antibodies to viruses (parainfluenza, RSV, CMV) increased in the same blood samples in which immunologic allergic sensitization was first evidenced. This coincidence suggests that certain viruses may contribute to the allergic sensitization process.

GABA-mediated biphasic inhibitory responses in hippocampus

Abstract: γ-Amlnobutyric acid (GABA) can have a biphasic effect on membrane potential when applied to certain central nervous system neurones1–3. Typically with iontophoresis, this effect is a negative–positive sequence of deflections and both phases are associated with an increase in conductance. However, iontophoretic application of neurotransmitter substances can produce effects even in cases where ordinary synaptic transmitter release is impossible; for example, on dorsal root ganglion cells. Thus, it is important in assessing the physiological relevance of the depolarising GABA response to determine if similar actions are produced synaptically. In addition, although the depolarising aspect of the GABA response has been attributed to activation of dendritic receptors, this identification has remained uncertain. Here, we have used the hippocampal slice preparation to demonstrate that a biphasic inhibitory response results from orthodromic, but not antidromic electrical stimulation in the presence of anaesthetic concentrations of pentobarbital. (For the sake of brevity, we use the term ‘biphasic inhibitory postynaptic potential (i.p.s.p.)’ to describe the response complex, although it seems likely that a combination of two distinct events, rather than two parts of a single event, occurs.) GABA antagonists and tetrodotoxin (TTX) were used to show that the depolarising phase is due to synaptically released GABA acting on dendritic sites in the CA1 region. Both negative and positive phases are associated with a large conductance increase, and both block cell firing, indicating their inhibitory nature. The ionic mechanism of the depolarising phase is not fully understood but seems to involve a chloride conductance increase. Although the functional significance of the depolarising sign of the i.p.s.p. is not clear, the dendritic location would provide very effective control over dendritic excitability.

Nucleotide sequence of the gene coding for the major protein of hepatitis B virus surface antigen

Abstract: DNA extracted from hepatitis B virus Dane particles has been cloned in bacteria using a plasmid vector. A full-length clone has been examined by restriction endonuclease analysis, and the nucleotide sequence of an 892-base pair fragment from cloned hepatitis B viral DNA encoding the surface antigen gene is reported. The amino acid sequence deduced from the DNA indicates that the surface antigen is a protein consisting of 226 amino acids and with a molecular weight of 25,398. The portion of the gene coding for this protein apparently contains no intervening sequences.

Electroencephalogram correlates of higher cortical functions.

Abstract: By means of two-stage, nonlinear multivariate pattern recognition, electroencephalograms (EEG's) were analyzed during performance of verbal and spatial tasks. Complex scalp distributions of theta-, beta-, and, to a lesser extent, alpha-band spectral intensities discriminated between the two members of a pair of tasks, such as writing sentences and Koh's block design. Small EEG asymmetries were probably attributable to limb movements and other uncontrolled noncognitive aspects of tasks. Significant EEG differences beteeen cognitive tasks were eliminated when controls for inter-task differences in efferent activity, stimulus characteristics, and performance-related factors were introduced. Each controlled task was associated with an approximately 10 percent reduction, as compared with visual fixation, in the magnitude of alpha- and beta-band spectral intensity. This effect occurred bilaterally and was approximately the same over occipital, parietal, and central regions, with some minor difference over the frontal region in the beta band. With these controls, no evidence for lateralization of different cognitive functions was found in the EEG.