bluuebunny/crossref_metadata_2025 huggingface dataset:
The Natural Blind-Spot (optic disc) within the Scotoma
Authors: Weiskrantz Lawrence
Published: November 2023

The optic disc provides a ready-made control for determining the discriminable limits of intra-ocular diffusion. As the size of this natural and absolutely blind area is fixed and known (5° × 7°), a target light that cannot be detected by the subject when it is positioned on the optic disc cannot cause detectable diffusion beyond a maximum angle determined by the distance between the edge of the target and the nearest region of sensitive retina.
Left Versus Right Eye
Authors: Weiskrantz Lawrence
Published: November 2023

On a number of occasions when the two eyes were compared it was seen that the left eye seemed better than the right. This was true with discrimination of orientation, and also with ‘presence/absence’. The question also arose in discussion of double dissociation of form and detection, when it was found that the impaired field was paradoxically better than the good field in a detection task at an extreme eccentricity (80°). Because stimuli at this eccentricity fall within the monocular crescent, it is possible that this surprising result of ‘super-normal’ performance in the impaired field might actually reflect a sub-normal performance of the unimpaired field because of its constricted pupil that resulted from the right cervical sympathectomy. In August 1983 we explored this possibility.
Detection of Direction of Contrast
Authors: Weiskrantz Lawrence
Published: November 2023

Because D.B., when he acknowledges having some sort of impression or feeling when a stimulus is abruptly presented, fails to ascribe any sense of ‘brightness’ to the experience — in fact, on one occasion he said, ‘it is as though I imagine that I am moving my finger in front of my eyes in the dark’ — it seemed possible that he would be unable to respond to the contrast of a stimulus on the ground. That is, he might treat a black spot on a grey ground as equivalent to a white spot on the same ground. We put this to the test in February 1975. Two grey cards were prepared, 24º × 17º in size, with a small black or white square, 3.6º × 3.6º, positioned in the centre. The cards were clipped to the Aimark perimeter at an eccentricity of 45° on the horizontal meridian. They were covered by a masking card, removed for a period of two seconds during each trial. The overhead fluorescent lamps were on, giving a light level on the card of 0.70 log ft lamberts. The level of the black square was 0 log ft lamberts, and of the white square, 1.1 log ft lamberts.
Review of Other Cases
Authors: Weiskrantz Lawrence
Published: November 2023

Examples of residual vision in a field defect are not difficult to find. Clinically, all cases of ‘relative’ scotomata, as distinct from ‘absolute’ scotomata, by definition possess degraded vision rather than total and profound blindness within the field defect. These are Gordon Holmes’s cases of putatively ‘incomplete lesions’ of visual cortex causing ‘an amblyopia, colour vision being generally lost and white objects appearing indistinct, or only more potent stimuli, as abruptly moving objects, may excite sensations.’ (1918, p. 361). The degree of ‘incompleteness’ would, according to writers such as Poppelreuter, determine the amount of uncovering of hierarchical layers of visual capacity that would occur, going from amorphous light sensitivity, to size perception without definite form, to amorphous form perception, to perception of discrete objects, to mild amyblyoia, to normal vision with decreasing severity (and possibly with complete recovery). Whether this hierarchy refers to degrees of severity or ‘completeness’ of lesions, to area 17 alone, or to area 17 plus surrounding cortex of areas 18 and 19, is, as we have reviewed, still unsettled (Chapter 4).
Fisherian Optimality Models
Authors: Roff Derek A
Published: November 2023

This type of model is a development of Fisher’s original approach to the study of evolutionary questions in which he took the Malthusian parameter, r, as the measure of fitness. As noted in Chapter 1, this measure is inappropriate under conditions in which a stable age distribution cannot be assumed, density-dependence or frequency-dependence is an important factor in the evolution of the traits under study, population dynamics is chaotic or fitness depends on the social setting. Even given these restrictions this type of model has proven to be a highly productive approach to the analysis of evolutionary questions and the generation of testable predictions. We first consider, in a little more detail than in Chapter 1, the fitness metrics assumed by models dealt with in this chapter. Next, I present a general scenario for analyses followed by illustrative scenarios (summarized in Table 1), and finally exemplary papers. MATLAB code for the scenarios is given in Section 2.18.
Humoral immune response to poliovirus
Authors: Minor P D
Published: November 2023

The only natural host for poliovirus is believed to be man, although experimentally it may produce symptoms in primates, and in some cases in mice. Therefore, in so far as immunity implies protection from disease, a discussion of humoral immunity to poliovirus must deal with the situation in humans. Extensive studies in animals, especially mice, have been carried out in order to characterize the antigenic structure of the virus and the findings can be applied to some degree to the natural infection. The creation of antigenically chimaeric viruses expressing dual antigenicity by recombinant DNA technology raises the possibility of more precise dissection of the immune response to polioviruses in more appropriate species.
Immunity to respiratory syncytial virus
Authors: Stott E J , Taylor G
Published: November 2023

During the last 30 years mortality from most communicable diseases has declined to less than 1% of former levels (Cockburn, 1979). However, there has been no parallel decrease in infectious respiratory diseases which remain a major cause of morbidity and mortality throughout the world. These account for 2.2 million deaths annually, the majority in infancy (Pringle, 1987).
Animal cell fermentation
Authors: Lavery Mark
Published: November 2023

In recent years, interest in the in vitro cultivation of animal cells has increased because of the need for production of interferon, monoclonal antibodies, various hormones, vaccines, and other cell products with potential human and veterinary applications. This has prompted research into basic biology and physiology of the cell which has seen the development of a variety of systems for the in vitro growth of animal cells. Some are a result of modifications or extensions to microbial stirred tank reactors (STR). Others have seen the emergence of air-lift reactors for submerged fermentation of animal cells. Further developments have involved intensification of the process, allowing fermentations to be operated at high cell densities. Newcomers to animal cell fermentation may find it difficult to select a system from the vast range available. It is not the intention of this chapter to recommend one manufacturer’s system over another but rather to describe the operation of those that are currently available and to guide the beginner towards successful animal cell fermentation.
Lipid-related second messengers
Authors: Farese Robert V , Cooper Denise R
Published: November 2023

The realization that many, if not all, peptide hormones rapidly stimulate changes in phospholipid metabolism has led to exponential advances in our understanding of the molecular mechanisms whereby these hormones regulate metabolic processes in their target tissues. Although most interest has focused upon hormones and other agonists which mobilize intracellular Ca++ by activating a specific phospholipase C that hydrolyses phosphatidylinositol-4´, 5´-bisphosphate (PIP2) (1, 2), it is clear that this hydrolysis is only one of several mechanisms which results in the generation of diacylglycerol, and activation of protein kinase C. The subject of PIP2 hydrolysis, and release of inositol-phosphate headgroups and their subsequent effects on Ca++ mobilization, will be reviewed in other chapters of this book. The present review will focus upon intracellular signalling substances which are contained in the diacylglycerol domain of phospholipids, including both the entire diacylglycerol molecule itself, and constituent fatty acids (in particular, arachidonic acid), and their subsequent activation of certain enzyme systems. To the greatest extent, this review will emphasize practical issues that investigators must face in exploring relevant areas experimentally, and the reader is referred to other recent reviews for more background information (3, 4).
Introduction
Authors: New Denis A T
Published: November 2023

Viviparity confers many advantages on the mammalian embryo but few on the mammalian embryologist. The inaccessibility of the embryo in the uterus has always been the main barrier to its study. For centuries the ‘dark recesses of the womb’ nmtured much mystery and speculation but gave birth to only the most bizarre theories of embryonic development (1). The advent of microscopy and histological sectioning techniques greatly increased the amount of accurate information available about embryo structure at different stages of gestation, but progress in understanding deveiopmental mechanisms was still severely hampered by the extreme difficulties of experimentation in utero. Fortunately, in recent times embryologists have been able to devise a variety of ways for bringing living embryos out into the light of day for manipulation and continuous observation. Gradually, reverence for the obscure is being replaced by wonder at the revealed.
Transn1ission electron microscopy and immunolabelling for light and electron microscopy
Authors: Martins-green Manuela m.
Published: November 2023

To understand cellular functions a detailed knowledge of the structural components involved is frequently necessary. Because cellular organelles generally are below the resolution of the optical microscope (OM), imaging of these structures must be accomplished by transmission electron microscopy (TEM). In addition, recent years have seen the advent of labelling techniques that allow delineation of the spatial distribution of specific molecules. Their gross distribution in tissues can be viewed in the OM, but the detailed molecular arrangements and interactions can only be obtained using TEM. During embryonic development and, in particular, during the early postimplantation stages, a number of rapid morphogenetic events take place, many of which occur in limited areas. To understand these events, it. is important to follow the processes involved in an accurate way, both structurally and chemically.
Extraction of macromolecules from embryonic material
Authors: Estibeiro J Peter , Copp Andrew j. , Cockroft david l. , Brown, Nigel A , Clarke David O
Published: November 2023

In this chapter we describe methods for the extraction and quantitation of nucleic acids (RNA and DNA), proteins, and lipids from postimplantation mammalian embryos. Many of the protocols presented are used routinely by the authors and have been modified for use with the very limited amounts of material which are characteristic of mammalian embryos.
Mass spectrometry of lipids
Authors: Evershed Richard P
Published: November 2023

Mass spectrometry is used for the structure elucidation of lipids, and their detection and quantification at trace levels. Through recent advances in sample introduction and ionization techniques probably all lipid classes can now be investigated using mass spectrometry. The coupling of chromatographic techniques (such as GC, HPLC, and SFC), to mass spectrometers allows separation of the individual molecular species with on-line mass spectrometric analysis of the eluting components. Accounts of gas chromatography (GC), and high-performance liquid chromatography (HPLC) of lipids appear in Chapters 4, and 5 so will not be discussed at length here. The reader is directed to refs 1-7 for accounts of the theory of mass spectrometry and ancillary techniques and reviews of the mass spectrometric analysis of lipids.
Analysis of defence gene transcriptional regulation
Authors: Harrison Maria J , Choudhary Ar Vind D , Lawton Michael A , Lamb, Christopher J , Dixon Richard A
Published: November 2023

A major question in molecular plant pathology is how exposure of plant cells to elicitors, or infection with micro-organisms, induces the appearance of defence gene transcripts leading to the accumulation of antimicrobial barriers. A number of defence response genes have now been cloned (see Appendix Al), and this has facilitated the analysis of transcriptional activation in response to microbial stimuli. Standard techniques of in vitro translation, Northern blotting, and RNAase- or S1 nuclease- protection can be used for the measurement of translatable mRNA activities and steady-state mRNA levels in relation to expression of plant defence and are described elsewhere (1, 2). This chapter deals, rather selectively, with direct analysis of transcriptional events and the factors which may interact with the promoters of plant defence genes in order to regulate their expression.
Gene expression using baculoviruses
Authors: Cameron Iain R , Bishop David H L
Published: November 2023

The Baculoviridae are a large family of viruses with over 1000 members. The majority have been isolated from insects, predominantly the Lepidoptera but also from Hymenoptera (e.g. sawflies), Diptera (e.g. craneflies), and Coleoptera (e.g. rhinoceros beetle), although examples have also been found in the Crustacea (e.g. shrimps). Baculoviruses have a natural role as regulators of insect populations in the wild, thus their greatest use, until recently, has been as biological control agents for a number of lepidopteran and hymenopteran species which are important pests in agricultural and forestry. Since they are not infectious to vertebrate species or plants they are thought to pose few safety problems. Several reviews are available in which the biology of baculoviruses is comprehensively described (1-3).
Progress in instrumentation technology for recording from single channels and small cells
Authors: Finkel Alan S
Published: November 2023

The development of the single-channel patch clamp marked a stunning evolution in our capacity to observe and understand membrane conductance processes. For the first time, the dynamic activity of individual membrane molecules could be observed. This was rare luck: there are very few disciplines in which this is possible. From the beginning, there have been arguments about the physiological significance of currents recorded from membranes that have been stretched across the mouth of the recording pipette and whose inner surfaces have been dialysed, but notwithstanding, an enormous amount of valuable data has been gathered using this technique.
Identification of G-protein-medicated processes
Authors: Dolphin A C , Scott R H
Published: November 2023

G proteins have the ability to bind guanosine triphosphate (GTP) and hydrolyse it to guanosine diphosphate (GDP). Many classes of protein possess this ability, including tubulin and the ribosomal elongation factor EF-Tu. However, in the context of signal transduction, G proteins also have recognition sites for receptors and for effectors, which may be enzymes or ion channels. Receptor activation by agonists enhances GTP binding to the G protein, and the activated G protein then selectively modifies the activity of the effector. Several recent reviews cover different aspects of G protein function (1, 2, 3).
The Use of Theoretical Methods in Protein Engineering
Authors: Daggett Valerie , Kollman Peter A
Published: November 2023

1. Introduction The ability to modify selectively proteins has increased our understanding of a variety of important, biologically relevant processes, including protein stability, catalysis, and substrate binding. These processes often defy experimental characterization at the molecular level; hence, there is a need for theoretical approaches to better understand these properties. With the advent of fast and affordable computers, it is now feasible to study complex macromolecular systems with computer simulation methods.
Principles of Protein Stability. Part 1—Reversible Unfolding of Proteins: Kinetic and Thermodynamic Analysis
Authors: Finn Bryan E , Chen Xiaowu , Jennings Patricia A , Saalau-Bethell, Susanne M , Matthews C Robert
Published: November 2023

1. Introduction Over 30 years ago Anfinsen and his colleagues demonstrated that the amino acid sequence is the primary determinant of the three-dimensional structure of a folded protein (1). This seminal observation stimulated numerous efforts to define the rules that govern the folding reaction (2–6). Unfortunately, little progress on solving the folding code has been made until recently. The main obstacle has been the high co-operativity of the unfolding transition. Only the native and unfolded forms are highly populated under equilibrium conditions; stable, partially folded forms are generally not detected. Transient intermediates, when they do appear, typically have lifetimes in the millisecond range, making it difficult to characterize their structures.
The 32P-postlabelling assay for DNA adducts: current status and applications to human samples
Authors: Randerath Kurt , Randerath Erika
Published: November 2023

Humans are exposed to a wide variety of genotoxic and tumour-promoting agents in their environment. While the important role of the tumour promoters in multistage carcinogenesis of experimental animals and humans is documented by many lines of evidence, no practical end-point has been developed for the biomonitoring of human exposure to tumour promoters. On the other hand, most known human carcinogens are tumour initiators, and fortunately a number of sensitive assays have been developed over the past 10 to 15 years to measure the formation of covalent addition products (adducts) of DNA, a key event in tumour initiation. Some of the assays, such as P-postlabelling, allow one to monitor activities of unidentified carcinogens and carcinogen mixtures at the target site (DNA), a feature that is particularly important for assessing human carcinogen exposure. Assays for DNA adducts are expected to acquire an increasingly significant role in the estimation of the role played by environmental carcinogens in the causation of human cancer. In this article we shall discuss the current status of the P-postlabelling assay and its application to human exposures.
Molecular and clonal analysis of in vivo hprt mutations in human cells
Authors: Albertini Richard J , O’Neill J Patrick , Nicklas Janice A , Allegretta Mark , Recio Leslie , Skopek Thomas R
Published: November 2023

There is no longer doubt that gene mutations occur in vivo in human somatic cells, and that methods can be developed to detect, quantify and study them. Four assays are now available for such purposes; two detecting mutations that a rise in bone marrow erythroid stem cells and two defining mutations that occur in T-lymphocytes. The red cell assays measure changes in mature red blood cells that involve either the blood group glycophorin-A locus or the haemoglobin loci; 6 the lymphocyte assays score for genetic events at either the X-chromosomal hypoxanthine phosphoribosyl transferase (hprt) locus, u.
The ‘rad-equivalence approach’ for assessment and evaluation of cancer risks, exemplified by studies of ethylene oxide and ethene
Authors: Tornqvist Margareta , Segerback D , Ehrenberg L
Published: November 2023

Tumorigenesis comprises a series of consecutive steps, starting with initiation of a single cell, followed by promotion and progression. Necessary events are initiation and promotion and, for the development of malignancy, one or several genetic changes in addition to the initiating one.
Studies to probe the mechanisms involved in the genotoxic action of chemicals
Authors: Bleasdale Christine , Ellwood Simon B , Golding Bernard T , Kennedy Gordon , Slaich Pritpal K , Taylor Oonah J , Watson William P
Published: November 2023

As part of a programme investigating the mechanisms of interaction of electrophilic reagents with nucleic acids we are studying reactions of oligonucleotides with selected genotoxic chemicals (formaldehyde, chloroacetaldehyde, glycidaldehyde, malonaldehyde, etc.) with the aim of providing a better understanding of the molecular basis of mutagenesis and carcinogenesis elicited by these chemicals. The key features of this research are:
Biomarkers of exposure to tobacco products
Authors: Hoffmann D , Hayley N J , Djordjevic M , Brunnemann K D , Hecht S S
Published: November 2023

Cigarette smoking increases overall mortality in men and women. It causes cancer of the lung, larynx, pharynx, upper digestive tract, pancreas, renal pelvis and bladder and is associated with an increased risk for cancer of the nasal cavity, cervix and, most likely, for leukemia.1--4 Smoking of cigars and pipes is also causally related to cancer of the respiratory tract, oral cavity, and esophagus, although in the case of lung cancer the association is not as extensive as with cigarette smoking.4 In addition to active smoking, involuntary smoking has been incriminated as a risk factor for cancer of the lung in non-smokers. Furthermore, use of chewing tobacco, and especially the oral use of snuff, are associated with cancer of the oral cavity.
Mutational diversity at the human hprt locus
Authors: Lambert B , Andersson B , He S -M , Hellgren D , Marcus S , Steen A -M
Published: November 2023

Humans are exposed to a variety of environmental agents which may give rise to mutation in somatic and germ-line cells. The identification of these agents and the study of their effects on human health are major problems in biomonitoring and genetic risk assessment. Characterization of mutagens with respect to the types of mutation they induce, and classification of mutations with regard to the mechanism by which they arise are important steps in this research. It is anticipated that such information will identify agents involved in germ call mutagenesis, and further elucidate the role of somatic mutation in carcinogenesis.
Exposure to styrene: comparison of DNA and haemoglobin adducts as biomarkers
Authors: Latriano L , Wazneh L , Dong Z , Lu S -J , Snyder C , Jeffrey A M
Published: November 2023

Styrene and styrene oxide are both widely used industrial chemicals. Styrene is used in the production of plastic and resins as well as styrenebutadiene rubber. It is also used to a small extent in various food products as a synthetic flavouring substance and adjuvantu. Styrene oxide is used as a raw material for the production of phenylstearyl alcochol used in perfume and an intermediate in the preparation of agricultural and biological chemicals, cosmetics, surface coatings, and in the treatment of textiles.
Individual variation and immunological effects in human biomonitoring
Authors: Ulewalter J , Miksche L
Published: November 2023

Studies of metabolism in animal toxicology are mainly carried out using high doses of test material. The importance of critical and possibly irreversible metabolic effects under usually high toxic doses for evaluation of the handling-risk for man is viewed with increasing scepticism.
DNA adducts in white blood cells versus other human tissues
Authors: Phillips D H , Schoket B , Hewer A
Published: November 2023

In recent years, sensitive techniques have been developed which make it possible to monitor humans for prior exposure to chemical carcinogens by examining their DNA for the presence of covalently bound carcinogens (termed ‘DNA adducts’). Because of the direct involvement of DNA adduct formation in the carcinogenic process, such techniques may provide a more reliable means of assessing biologically-significant exposure to carcinogens than previous methods, and may contribute to prospective risk assessment in areas pertaining to occupational health and human population monitoring. One of the DNA adduct determination methods, P-postlabelling analysis, is particularly suited to monitoring exposure to complex mixtures of carcinogens.
Indicators of aromatic adducts in human DNA
Authors: Weston A , Bowman E D , Povey A C , Manchester D K , Newman M J , Beland G E Trivers. F A , Farmer P B , Poirier, M C , Harris C C
Published: November 2023

Human cancer risk assessment (biochemical and molecular epidemiology) seeks to identify those individuals at risk of cancer by virtue of their lifestyle, occupation, or inherited host factors. The genotoxic dose of a carcinogen (biologically effective dose) is related to the amount of the xenobiotic reaching the target tissue, competing metabolic pathways of activation of detoxification, and DNA repair. Therefore, the development of highly sensitive methods for the detection of carcinogen-DNA adducts is an important facet in molecular epidemiology.
Qualitative and quantitative separation of human apolipoproteins
Authors: Dieplinger Hans , Menzel Hans-Jürgen , Utermann Gerd
Published: November 2023

Lipoproteins are the predominant lipid transport vehicles in human plasma. Their protein components are called apolipoproteins and represent a class of evolutionarily related polypeptides. The amino acid and nucleotide sequences as well as the chromosomal localization is known for all major apolipoproteins. Table 1 shows the molecular weights and plasma concentrations of the different apolipoproteins. The various lipoproteins in human plasma have a characteristic apoprotein composition (for a review see reference 1). The protein moiety of high density lipoproteins (HDL) consists primarily of apo AI and apo AIi with apolipoproteins apo AIV, C, D, and E as minor constituents. Within high density lipoproteins several subclasses exist that contain various combinations of these apolipoproteins (2).
Centrifugal methods for characterizing macromolecules and their interactions
Authors: Rickwood David
Published: November 2023

Much of the early centrifugation work was centred on the behaviour of macromolecules, particularly proteins, during sedimentation. The discrete high molecular weights of proteins and nucleic acids made them ideal for extensive studies using the analytical ultracentrifuge. This emphasis reflected the importance of these molecules in the structure and, function of cells. Sub-sequently, a great deal of analytical work has been carried out using preparative ultracentrifuges. Much of this work was focused on the sedimentation of macromolecules and the effects of changes in conformation and macromolecular interactions. Macromolecules can be separated on the basis of their sedimentation rate, determined primarily by their size and conformation (rate-zonal centrifugation), or on the basis of density in different types of gradient solution (isopycnic centrifugation). However, the development of sophisticated electrophoretic techniques (1,2) has resulted in much of the work on investigating the molecular mass of macromolecules now being carried out using one of the electrophoretic methods. In addition, the rapid sequencing methods now available for DNA and proteins (3,4) make it possible to determine the size of molecules in a very precise manner, much more accurately than any centrifugation or electrophoretic method.
Immunological identification of extracellular matrix components in tissues and cultured cells
Authors: Amenta Peters , Martinez-Hernandez Antonio
Published: November 2023

Within the last two decades considerable advances have been made in the knowledge of extracellular matrix (ECM) composition and function. The initial concept of the ECM was that of an inert, support structure morphologically characterized by the presence of banded and beaded fibres, fibrils, filaments, granular material, and specialized matrices-the basement membranes. The isolation of the individual ECM components has led to the development of monospecific antibodies. One application of these antibodies has been for immunohistochemical studies. This approach provides information, unattainable by biochemical means, concerning the distribution of the individual ECM components. Immunohistochemistry can be performed at both the light and electron microscopic level. Light microscopy immunohistochemistry provides a preliminary road map of matrix distribution in tissues and organs. However, only electron microscopy with its superior resolution, can define the exact matrix-matrix and cell-matrix relationships. Cell culture studies have provided data on the synthetic capacity of individual cell types in culture; however, in vitro cell behaviour may not reflect the in vivo situation. Like in situ hybridization, immunohistochemical studies can define the synthetic profile of cells in vivo and in vitro. Localization of antigenic determinants within cellular synthetic organelles can be achieved at the electron microscopic level.
The analysis of two-dimensional polyacrylamide gels for the construction of protein databases
Authors: Dunn Michael J
Published: November 2023

High-resolution two-dimensional polyacrylamide gel electrophoresis (2D PAGE) is a technique which separates a mixture of proteins according to their intrinsic charge properties by isoelectric focusing (IEF) in the first dimension and according to their molecular size by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) in the second dimension (1). This technique is capable of resolving simultaneously complex mixtures of proteins containing several thousand components, and makes 2D PAGE a powerful tool in many areas of biological and biomedical research (2). It results in complex two-dimensional protein profiles from which only a limited amount of information can be extracted by simple visual inspection.
Networking for the novice
Authors: Harper Robert
Published: November 2023

Picture this! A scientist wants to exchange some information with a colleague in California. She writes him a letter and posts it. It takes a week to get there. It lies on his secretary’s desk for a week before he reads it and dictates a reply. The secretary types the reply and puts in in the post. A week passes before the reply is received. Almost a month has passed before the scientist gets an answer to her question. Now picture this! There is an eight-hour time difference between the USA and Finland. Before leaving work our scientist sends some E-mail to a friend in California. The message is waiting for him when he logs into his computer in the morning. He replies immediately by E-mail. When the Finnish scientist comes into work next morning the answer to her question is waiting.
Probability and genetic counselling
Authors: Young Ian d.
Published: November 2023

Over the years many definitions of genetic counselling have been proposed. A theme common to all is the concept of a communication process, whereby patients are informed of the probability that they may develop or transmit a genetic disease along with details of its consequences, and possible approaches to its prevention. It is readily apparent from this definition that genetic counselling is a multi-faceted exercise which draws upon a number of skills. These include patience, objectivity with a non-judgemental approach, insight into human nature and aspirations, and, not least, a sound knowledge of genetics and medicine. To these can be added the ability to calculate probabilities, and it is with this particular aspect of genetic counselling that this text is concerned. It might reasonably be argued that patients at a genetic counselling clinic are more concerned with the nature of risk than with its precise numerical value, or, as Fraser1 has succinctly concluded, ‘Let us not get so preoccupied with the risks that we lose sight of the stakes.’ Certainly several studies of the longterm impact of genetic counselling have concluded that it is the burden of a disorder rather than its precise risk which is of greater concern to patients and prospective parents,2-4 and indeed many patients simply wish to know whether risks are ‘high’ or ‘low’. Nevertheless this does not detract from the importance of giving correct and precise information, an obligation neatly summarized by Lalouel et al.,  5 who maintain that ‘The question of whether consultees demand as much specificity should be subordinate to the question of whether counsellors are justified in providing less.’
Sex-linked recessive inheritance
Authors: Young Ian d.
Published: November 2023

In sex-linked recessive disorders the condition is manifest in the male who is described as being ‘hemizygous’, whereas, by definition, the heterozygous carrier female is not affected, although careful examination or appropriate investigations may occasionally reveal subtle abnormalities. When a female is known to be a carrier, then each of her sons runs a risk of 50 per cent for inheriting the disorder in question whilst each daughter is at 50 per cent risk for being a carrier. When an affected male reproduces, all of his daughters will be carriers as they will all have inherited his X chromosome and all of his sons will be unaffected as they must have inherited his Y chromosome. Unfortunately the provision of risks for sex-linked recessive disorders is rarely as easy as this simple outline would suggest. For example, if an affected male represents an isolated case in a particular family, then it becomes essential to try to establish whether he represents a new mutation or whether his mother is a carrier. The existence of unaffected uncles, brothers and nephews may have to be taken into account as may the results of appropriate carrier tests undertaken not only on the mother but also on other close female relatives in the matrilineal line.
Chiral separations by gas chromatography
Authors: Taylor David R
Published: November 2023

The separation of one enantiomer (optical isomer) from another is difficult to achieve by any chromatographic procedure. This is because any two enantiomers are structurally related to one another in the same way as an object and its mirror image, and therefore have identical physical and chemical properties as long as they remain in an achiral (symmetrical) environment. Only when observed in plane-polarized light, as in a polarimeter, or when interacting with a chiral (asymmetrical) reagent or chiral surface, do two enantiomers reveal differences which can be used in analysis or to bring about their separation.
The role of gas chromatography in petroleum exploration
Authors: Harriman Gareth E
Published: November 2023

It is now widely accepted that petroleum has a biogenic origin, having derived from plant or animal remains, or a mixture of both. After death, most organisms and plant debris decay and return (through oxidative processes) to the atmosphere as carbon dioxide. A small amount (<1 %) of this organic matter, however, is deposited in aquatic environments that are not oxidizing but reducing, with the net result that some of the organic matter is preserved within the sedimentary record. As further sedimentation takes place, and the burial depth of the organic-rich sediments increases, the organic matter undergoes biological and chemical changes (diagenesis), which can lead to the formation of petroleum source rocks. These source rocks, under appropriate conditions of temperature and pressure, may generate and expel liquid hydrocarbons which can subsequently migrate to suitable traps where they pool as petroleum accumulations.
Combined gas chromatography— mass spectrometry
Authors: Evershed Richard P
Published: November 2023

Gas chromatography-mass spectrometry (GC-MS) remains the most effective technique for the separation, detection, and characterization of the components of complex organic mixtures (1). GC and MS are regarded as the ‘natural combination’, compared to other combined chromatographic-mass spectrometric techniques, as both display optimum performance with volatile or semi-volatile materials when sample sizes per component are in the nano-gram range (2). Considered in its simplest form, a mass spectrometer (MS) is a device for producing and mass measuring ions. In the case of organicmolecules, the mass and relative abundance of molecular (M+’) or pseudomolecular ions (e.g. [M + Ht) and fragment ions are a direct reflection of molecular structure. Hence, mass spectrometry is unique in its ability often to yield complete structure assignments without needing to use other physicochemical techniques. Although isomeric structures may be distinguished on the basis of their mass spectra alone, such distinctions are often best made by considering elution orders in combined chromatographic/mass spectrometric analyses.
Structural analysis of prenylated proteins
Authors: Gelb Michael H , Farnsworth Christopher C , Glomset John A
Published: November 2023

The post-translational attachment of prenyl groups to proteins in eukaryotic cells has been recently reported (1-4). To date, two isoprenoid products derived from mevalonic acid (MVA), 15-carbon farnesyl groups or 20-carbon geranylgeranyl groups, have been detected. These prenyl groups are attached to proteins via thioether linkages to one or more cysteine residues that are located in the C-terminal region. Many of the prenylated proteins that have been so far structurally characterized share a common, cDNA-inferred, C-terminal sequence motif, Cys-Ali-Ali-Xaa, where Cys is cysteine, Ali is an aliphatic amino acid, and Xaa is the C-terminal amino acid. The attachment of farnesyl or geranylgeranyl groups to cysteines of the Cys-Ali-Ali-Xaa motif is catalyzed by distinct protein prenyltransferases. This reaction is followed by a specific proteolytic step(s) which removes the last three amino acids (Ali Ali-Xaa) and finally methylation of the newly exposed prenyl-cysteine a carboxyl group (Figure 1).
Synthesis of Oligonucleotide Phosphorodithioates
Authors: Beaton Graham , Dellinger Douglas , Marshall William S , Caruthers Marvin H
Published: November 2023

Over the past several years, the development of high yielding, rapid methods for synthesizing DNA (1-3) have led to a large number of applications for oligonucleotides (4). These include its use for cloning and synthesizing genes (5), as primers for sequencing DNA and various PCR applications (6), mutagenesis of genes in a site-specific manner (7), examination of how nucleic acids interact with proteins (8), and for studies on nucleic acid structure (9). Mainly because of these results, many have discovered that synthetic DNA needs to be further modified so that it resists hydrolysis by nucleases and contains reporter groups, haptens, cross-linking reagents, sugars, steroids, and peptides. Invariably such interest has stimulated the development of new analogues and new chemistries for synthesizing these derivatives. In this chapter, the chemical synthesis of a potentially very useful analogue for many of these applications, which we call dithioate DNA, will be discussed.
Social aspects of alcohol consumption
Authors: Rae(NL) Dr J
Published: November 2023

The origin and mission of the Portman Group. Comparison with similar drinks industry groups worldwide. The position of the Portman Group within the alcohol field in the UK. Close relations with government and collaboration with other groups that share our aim. Our approach to social aspects of alcohol consumption. Examples of issues and of the Portman Group’s response [1] proof of age card [2] educational initiatives [3] research programmes [4] alcohol and disorder. The importance of positive benefits of moderate consumption. The Portman Group’s long term aims and the chances of success. What we can learn from the experience of other countries and vice versa.
Rapid method of identification and analysis of barley varieties in a malting plant
Authors: Vasconcelos L , Jesus A Christina , Andrade A , Mello-Sampaio T
Published: November 2023

The implementation of assessment of quality in our malting plant made us aware of the need to have a rapid method for routine cultivar identification and determination of varietal purity of barley to complement the traditional morphological analysis.
Der Verbleib von Pestizidrückständen des Hopfens bei der Herstellung von Hopfenprodukten
Authors: Forster A , Beck B , Gehrig M
Published: November 2023

Im Hopfenanbau wird chemischer Pflanzenschutz betrieben, um den Krank- heitsbefall zu kontrollieren. Neben der Rückstandssituation im Rohhopfen interessiert der Verbleib von Pestiziden bei Hopfenverarbeitungen wie der Trocknung, mechanischer Lupulinkonzentration, Extraktion und Isomerisierung.
Flocculation characteristics of brewer’s yeast during fermentation
Authors: Kempers J , Aar P C van der , Krotje J
Published: November 2023

Control of yeast flocculation is very important, especially in brewery groups where fermenters of varying sizes and geometries are in use. Recently we started a multidisciplinary project to study the biochemical, physical and physiological aspects of flocculation. A quantative test for flocculence (the potential to flocculate) has been developed. With this test it has been shown that during fermentation yeast cells become flocculent at the time of cell division arrest. The concentration of wort amino acids in standard 12 °P wort did not influence flocculence in subsequent fermentations. Although the oxygen concentration of the pitching wort has a tremendous effect on fermentation rate the expression of flocculence is not affected.
Why is ester formation in brewery fermentations yeast strain dependent?
Authors: Ramos-Jeunehomme C , Laub R , Masschelein C A
Published: November 2023

From practical knowledge it is widely recognized that, under the same fermentation conditions, the amounts of esters formed are largely dependent on the strain of yeast which is used. Alcohol-acetyltransferase (AT) has been shown to be responsible for in vitro acetate ester synthesis. We previously demonstrated the existence of cytosolic and membrane-bound AT. The cytosolic fraction appeared to have a key function in determining ester formation. It has been shown that brewers’ yeast strains exhibiting higher ester synthesizing capacities also contain larger proportions of cytosolic AT activity during the batch fermentation cycle.
Main fermentation with immobilized yeast
Authors: Linko Matti , Kronlöf Jukka
Published: November 2023

Main fermentation with immobilized yeast is technically more difficult than “lagering”, because of vigorous fermentation and growth of yeast. Immobilization with adsorption and ionic binding holds promise. Scanning electron microscope revealed a distinct difference in the type of binding on various carriers such as DEAE-cellulose or porous glass.
Zur Lichtstabilität von Bier
Authors: Mändli Hugo , Anderegg Paul
Published: November 2023

Sun struck beer has a very unpleasant off-flavour, the intensity of which is correlated with the concentration of 3-methyl-2-buten-l-thiol, also called “sunlight mercaptan”. The development of a quantitative assay for this substance was taken as the occasion to investigate various parameters which are linked with this type of spoilage and to correlate the analytical and sensory data. The protecting action of ascorbic acid on light stability has been elucidated. The known dependence of protection on the colour and type of bottle glass was reviewed and the investigation extended to PET and PVC bottles. Central to this work was the problem of the fate of sun struck flavour in a beer which was once exposed to light and subsequently has been returned to light protected storage.
Yeast proteolytic enzyme activity during fermentation
Authors: Ormrod LH L , Lalor E F , Sharpe F R
Published: November 2023

An acid protease of yeast origin has been detected in final beers. A rapid, sensitive, enzyme assay has been used to monitor the release of this enzyme from yeast, during 17-hectolitre scale fermentation trials.
Load cell monitoring and control of fermentation
Authors: Brodtkorb Leif Christian , Lie Sturla , Johannessen Øyvind
Published: November 2023

Nine cylindroconical vessels of 955 hl capacity have been equipped with one load cell each in order to test a simplified system for monitoring and feedback control of the fermentations through weight loss of CO2 evolved. In addition the load cells supervise wort filling, time of pitching and the CIP cycles.
Immunchemischer Schnellnachweis bierschädlicher Bakterien
Authors: Eger C , Donhauser S , Winnewisser W , Röhm B
Published: November 2023

The increasing rapidity of modern fermentation and maturation processes leads to an ever widening discrepancy between the rate of beer production and the period needed for microbiological detection methods. The authors favour a combination of the specificity of immunochemical methods with the high sensitivity of flow cytometry as a route to rapid detection.
Die Kaltfiltration als Alternative zur Kurzzeiterhitzung vor der Bierabfüllung?
Authors: Eils H -G , Frieling J
Published: November 2023

Two systems for the cold sterilisation of beer immediately before filling have been tested at Beck’s Brewery—one involving membrane filtration the other mass filtration. The biological security, effects on beer quality and economics of both systems are investigated.
The relation between the chemical structure of polysaccharides and their physical properties
Authors: Rinaudo M
Published: November 2023

In this paper, the roles of the chemical structure and stereo regularity on conformation of polysaccharides are discussed. Stereo regularity is specially important in the inter chain interactions leading to gelation. Finally the chain dimensions of ionic polysaccharides are discussed introducing the worm-like chain model. Prediction of radius of gyration and intrinsic viscosity for alginates, xanthan and succinoglycan is discussed and compared with experimental values.
Structure of gelatin solutions and gels
Authors: Herning T , Pezron I , Takerkart G , Tournier-Dumas S , Djabourov M
Published: November 2023

We have investigated gelatin solutions and gels by using a variety of scattering techniques : light and small angle neutron scattering, together with dynamic light scattering. These experiments allow us to fully characterize the conformation of gelatin chains and their dynamic behavior. In dilute solutions, the radius of gyration, the persistence length, the virial coefficient and the self-diffusion coefficient have been measured. With increasing concentrations, in the semi-dilute state, we determined the typical hydrodynamic and static correlation lengths, but we also point out that these solutions are not totally homogeneous, as aggregates are formed whose origin is discussed. Very few differences appear between the scattering of sols and gels, indicating that the supramolecular assemblies in the gel state almost preserve the initial topology. Besides, quasi-elastic light scattering is shown to provide an interesting tool for investigating the sol-gel transition, which can be compared to the rheological measurements.
A new method to determine the gelling temperature of food gels
Authors: Krag-Anderson S , R.S¢Derberg J
Published: November 2023

A method to determine the gelling temperature of food gels based on the different thermal conductivity of a solution and a gel is described. The temperature in the gelling system and in the reference is measured on cooling at a constant rate. The temperatures are fed into a computer and the gelling temperature is calculated. The gelling temperature is defined as the temperature at which the differentiated temperature difference starts to increase.
Rheological characterisation of carrageenan gels
Authors: Roesen Jens
Published: November 2023

Carrageenan gels show different rheological properties depending on carrageenan type and gel composition. Carrageenan gel textures can vary from rubber-like or brittle to pasty. A gel can have a high elastic modulus, but collapse at a small deformation. By determining rheological characteristics of gels made from well defined (seaweed species extraction conditions) carrageenans, a good correlation can be established between carrageenan type and gel properties. This relationship, in turn, can be used to deduce from rheological characteristics of an unknown carrageenan to its likely molecular structure and origin. Rheological characterization is further a useful instrument in describing the influence of other gel components (salts, sugars a. o.) on carrageenan gels.