Cloning of the human alpha 1 antichymotrypsin gene and genetic analysis of the gene in relation to alpha 1 antitrypsin deficiency

Deficiency of alpha 1 antitrypsin (Pi) is clinically heterogeneous and the unpredictability of the clinical manifestation in a person of phenotype PiZ, which may vary from severe childhood liver disease to normal health, is a problem in genetic counselling. This problem may increase as couples at risk who have not had an affected child are identified in screening programmes. One possibility is that genetic variation of other protease inhibitors may influence the prognosis. With this in mind we report the isolation of the human gene for alpha 1 antichymotrypsin (AACT) on a series of cosmid clones, with restriction mapping of about 70 kb around the gene. A probe pACE3.4 derived from the 5' end of the gene defines sequences which have been assigned to chromosome 14 using somatic cell hybrids and has been used to show a common TaqI polymorphism with allele frequencies of AACT6 = 0.7 and AACT3 = 0.3 in Europeans. pACE3.4 is closely linked to alpha 1 antitrypsin (maximum lod score in males +2.29 at theta = 0; in females Z = +6.11 at theta = 0.032). Analysis of Pi-AACT haplotypes in 31 families ascertained through PiZ or PiSZ subjects did not show any linkage disequilibrium. The distribution of AACT6 and AACT3 alleles in 16 unrelated PiZ patients presenting with childhood liver disease and five unrelated PiZ patients with adult chest disease did not differ significantly from each other. These results suggest that if genetic variation at the AACT locus does influence the outcome of alpha 1 antitrypsin deficiency, such variation is not in linkage disequilibrium with the AACT polymorphism reported here.

Oestradiol changes the dielectric structure of bilayer membranes

The addition of the hormone Oestradiol to Phosphatidylcholine-Cholesterol membrane changes the frequency dependence of the membrane impedance. It increases severalfold the electrical admittance of the polar regions and consequently provides a conducting shunt from the hydrocarbon region to the aqueous phase.

Concanavalin A receptor ‘tipping’ in Tetrahymena and its relationship to cell adhesion during conjugation

Shortly after mixing cells of complementary mating types of Tetrahymena, the cells develop the ability to pair, a process inhibited by ConA, and the region joining the cells becomes ringed with ConA receptors. This study examines the arrival of ConA receptors at the conjugation junction by looking at cells in the period between mixing and pairing. By brief incubations with F-ConA at intervals after mixing, it was ascertained that some cells had fluorescent tips as early as 15min. A kinetic analysis revealed that ‘tipping’ occurs in a manner that appears to be related to subsequent cell pairing. Cytoskeletal frameworks (CFs) were isolated under conditions in which ConA receptors remain attached. Western blot analysis of these structures revealed four major and several minor ConA-binding proteins. However, between mixing and the establishment of over 80% paired cells, changes occurring in the banding pattern were slight. This indicates that new populations of ConA receptors are not produced to any great extent after mixing. Head- on examination of CFs showed that it was possible to monitor simultaneously the process of tip transformation (widening of the nonciliated area of the tip) and ConA-receptor localization. ConA receptors originate posterior to the tip, begin to occupy the surface of the tip in clusters as the tip widens and eventually coat the transformed tip. Finally, as cells join pairs, the receptors relocate to a ring around the conjugation junction. These data suggest that ConA receptors accumulate at the anterior tips and then concentrate at the edge of the junction. This could provide a mechanism for controlling cell-cell adhesion.

The interrelationship of substance abuse and posttraumatic stress disorder. Epidemiological and clinical considerations

This chapter reviews the data available on the relationship of substance abuse and posttraumatic stress disorder (PTSD). Delimiting the review to those studies of Vietnam veterans, we found that levels of combat exposure seemed to be positively related to subsequent alcohol use, although not all studies confirmed this relationship. When studies of patients seeking treatment for PTSD were examined, we learned that 60-80% of these patients had concurrent diagnoses of substance abuse, alcohol abuse, or dependence. Methodological limitations of all the studies are discussed and conclusions regarding the status of the PTSD-substance abuse relationship are drawn cautiously. Alternative suggestions for treatment are presented and discussed.

Autoimmune serum containing an antibody against a 94 kDa nucleolar protein

Little information exists on how various nucleolar proteins function in ribosome biogenesis. Of special interest is that group of nucleolar proteins which are not incorporated into mature ribosomes because they are candidates for a role in the regulation of ribosome construction. Non-ribosomal nucleolar proteins can be analyzed using autoimmune sera from scleroderma patients which often contain antinucleolar antibodies. One such serum, designated ScBr, is shown by indirect immunofluorescence to react specifically with nucleoli in cells of 3 different mammalian species, indicating that the antigen is at least partly conserved evolutionarily. It is not RNase-sensitive, but is completely eliminated after incubation with pronase and 2 M NaCl. Immuno-electron microscopy was carried out on Lowicryl ultrathin sections to localize the antigen. The labeling was observed over both the granular and the dense fibrillar component but not the fibrillar centers, indicating that the antigen is associated with ribosomal RNA transcription sites and ribosome assembly into precursor particles. In addition, the antibody was localized to small nucleoplasmic entities, termed dense nuclear bodies. This could indicate a relationship between nucleoli and dense nuclear bodies. By immunoprecipitation, only a single protein of 94 kDa molecular weight was revealed. By immunoblotting, the band at 94 kDa was found to be the only positive band for high ScBr dilutions. Observation of the behavior of the antigen during mitosis revealed that it became dispersed into the cytoplasm after breakdown of the nuclear envelope, lining most of the chromosomes rather than remaining associated with the NOR-chromosomes. The antigen appeared to be restored to nucleoli only in late telophase; phase-dense prenucleolar bodies of early telophase cells did not show positive staining for the antigen. During actinomycin-D RNA synthesis inhibition as well as in non-stimulated lymphocytes the positive staining is greatly decreased. These results were consistent with a role for the 94 kDa nucleolar protein in the process of preribosome assembly.

Episodic and semantic memory: a comparison of amnesic and demented patients

Episodic (recall of passages) and semantic (letter and category fluency) memory tasks were administered to Alzheimer's Disease (early stages), Huntington's Disease (HD), and alcoholic Korsakoff patients matched for overall severity of dementia. Although all three patient groups were severely (and equally) impaired on memory for passages, only the Alzheimer and Korsakoff patients emitted numerous intrusion errors. On the fluency tasks, the performance of the mild Alzheimer patients was distinguishable from that of the other two patient groups. On both fluency tasks, the HD and Korsakoff patients demonstrated severe and moderate deficits, respectively, whereas the mild Alzheimer patients were impaired only on the category fluency task. As with the episodic memory test, the Alzheimer and Korsakoff patients made more perseverative errors than did the HD patients on letter fluency. These findings suggest that Alzheimer and HD patients' impairments on episodic and semantic memory tasks reflect different underlying processes. The performance of Alzheimer patients is affected by their language dysfunction and an increased sensitivity to proactive interference; the deficits of the HD patients appear due to a general retrieval problem. Similarities in the error patterns (i.e., perseveration errors) of Alzheimer and Korsakoff patients are discussed with regard to recent neuropathological findings.

Comparison of microdissected sections from the human cataractous lens by antisera to synthetic peptides

Polyclonal antiserum has been made against beta crystallin from human lens, and against synthetic peptides corresponding to the N- and C-terminal sequences of bovine beta Bp crystallin. A solid-phase radioimmunoassay has been used to quantitate binding of these antisera to soluble proteins from microdissected sections. The results of this analysis demonstrate the feasibility of using radioimmunoassay analysis in combination with peptide antisera to determine statistically significant changes in protein antigenicity from opaque versus transparent regions from the same human cataractous lens.

Verbal memory deficits associated with major affective disorders: a comparison of unipolar and bipolar patients

The verbal learning and fluency of patients with unipolar and bipolar depression were compared to those of normal controls and patients with Huntington's disease. The data demonstrated that the recall and recognition performance of both groups of depressed patients were impaired relative to the performance of normal control subjects. The bipolar patients, however, were more impaired than the unipolar patients on both tasks (P less than 0.024 and P less than 0.022, respectively). In addition, the unipolar patients generated more correct responses on a test of verbal fluency (P less than 0.04). The performance of the bipolar patients was, in fact, similar to that of patients with Huntington's disease, a progressive degenerative disorder that primarily affects subcortical areas.

Electromechanical stresses produced in the plasma membranes of suspended cells by applied electric fields

We analyze the electrical and mechanical stress in the bounding membrane of a cell (or vesicle) in suspension which is deformed by an external applied field. The membrane is treated as a thin, elastic, initially spherical, dielectric shell and the analysis is valid for frequencies less than the reciprocal of the charging time (i.e. less than MHz), or for constant fields. A complete analytic solution is obtained, and expressions are given which relate the deformation, the surface tension and the transmembrane potential difference to the applied field. We show that mechanical tensions in the range which lyse membranes are induced at values of the external field which are of the same order as those which are reported to lyse the plasma membranes of cells in suspension.

Labeling in vivo of serotonin uptake sites in rat brain after administration of [3H]cyanoimipramine

The properties of sites in rat brain labeled in vivo after administration of [3H]cyanoimipramine ([3H]CN-IMI) have been studied. The radioactivity in hypothalamus and cortex 20 min to 2 hr after [3H]CN-IMI administration was reduced in rats pretreated with chlorimipramine (10 mg/kg) 5 min before [3H]CN-IMI. No effect of chlorimipramine pretreatment was seen in the cerebellum; levels of radioactivity in this tissue were subtracted from total levels in hypothalamus and cortex to define specific binding. This represented approximately 50 and 30% of total binding in hypothalamus and cortex, respectively. Specific binding in hypothalamus and cortex was reduced by a number of drugs which are potent blockers of serotonin uptake and the binding was inhibited in a stereoselective manner by the stereoisomers of norzimelidine. In contrast, pretreatment with drugs which are weak inhibitors of serotonin uptake had no effect on specific binding. Experiments using increasing doses of [3H]CN-IMI showed that the binding in vivo was saturable. Lesioning rats with the serotonin neurotoxin 5,7-dihydroxytryptamine resulted in an 80% decrease in the specific binding in hypothalamus and a 35% decrease in cortex. The potencies of drugs to inhibit the specific binding of [3H]CN-IMI in vivo were highly correlated with their previously published potencies for inhibiting serotonin uptake in human blood platelets in vitro and for preventing the serotonin depletion induced by 4-methyl-alpha-ethyl-metatyramine in vivo. These results indicate that [3H]CN-IMI can be given to rats to provide a measure of serotonin uptake sites in the central nervous system in vivo.

Localisation of Y chromosome sequences in normal and 'XX' males

Three unique sequences derived from the Y chromosome have been mapped within the human genome. A Y specific sequence DYS20 is localised to Yq11.2. DXYS25 and DXYS27 are both X-Y homologous sequences which map to the Y short arm and to Xq21. DXYS25 maps more distally than DXYS27, on the Y short arm and on the X long arm. Y specific restriction fragments for these two sequences are shown to be present in the genome of two XX males, and an aberrant signal for DXYS25 is demonstrated at the tip of an X chromosome short arm in one XX male by in situ hybridisation. The implications of these findings for the location of the testis determining factor are discussed.

The Mechanics of Injury to Isolated Protoplasts following Osmotic Contraction and Expansion

Micro-osmotic manipulation was used to determine the influence of osmotic contraction on the expansion potential of individual protoplasts isolated from rye (Secale cereale L. cv Puma) leaves. For protoplasts isolated from leaves of nonacclimated plants (NA protoplasts), osmotic contraction in sufficiently hypertonic solutions (>1.53 osmolal) predisposed the protoplasts to lysis during osmotic expansion when they were returned to isotonic conditions (0.53 osmolal). In contrast, for protoplasts isolated from leaves of cold acclimated plants (ACC protoplasts), osmotic contraction in either 2.6 or 4.0 osmolal solutions was readily reversible. Following osmotic contraction, the resting tension (gamma(r)) of NA protoplasts was similar to that determined for protoplasts in isotonic solutions (i.e. 110 +/- 22 micronewtons per meter). In contrast, gamma(r) of ACC protoplasts decreased from 164 +/- 27 micronewtons per meter in isotonic solutions to values close to zero in hypertonic solutions. Following expansion in hypotonic solutions, gamma(r)'s of both NA and ACC protoplasts were similar for area expansions over the range of 1.3 to 1.6. Following osmotic contraction and reexpansion of NA protoplasts, hysteresis was observed in the relationship between gamma(r) and surface area-with higher values of gamma(r) at a given surface area. In contrast, no hysteresis was observed in this relationship for ACC protoplasts. Direct measurements of plasma membrane tension (gamma) during osmotic expansion of NA protoplasts from hypertonic solutions (1.53 osmolal) revealed that gamma increased rapidly after small increments in surface area, and lysis occurred over a range of 1.2 to 8 millinewtons per meter. During osmotic expansion of ACC protoplasts from hypertonic solutions (2.6 osmolal), there was little increase in gamma until after the isotonic surface area was exceeded. These results are discussed in relation to the differences in the behavior of the plasma membrane of NA and ACC protoplasts during osmotic contraction (i.e. endocytotic vesiculation versus exocytotic extrusion) and provide a mechanistic interpretation to account for the differential sensitivity of NA and ACC protoplasts to osmotic expansion from hypertonic solutions.

Cerebral serotonin regulation by phenylalanine analogues and during hyperphenylalaninemia

Severe hyperphenylalaninemia induced in infant rats by 3 days of treatment with p-chlorophenylalanine (p-cl phe) plus phenylalanine (phe) did not lower the tryptophan concentration of the brain, and the cerebral serotonin (5-HT) deficiency was attributable entirely to the known suppression to tryptophan hydroxylase (TPH) by p-cl phe. The decrease in 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) was thus no more pronounced than in rats which, treated with p-cl phe alone, were devoid of hyperphenylalaninemia. Suppression of TPH was found to also underlie the decrease in cerebral 5-HT caused by treatment with alpha-methylphenylalanine (alpha-mephe) alone: a 22% loss of midbrain TPH activity was detectable 24 hr after an injection only, reverted toward the normal during the next 2 days, and was clearly unrelated to the weak competitive inhibition of the enzyme by alpha-mephe in vitro. However, alpha-mephe (unlike p-cl phe), when administered together with phe, did not suppress TPH, nor did it counterbalance the reduction of cerebral tryptophan uptake by excess phe. Thus the 5-HT diminution in the rat model of phenylketonuria produced by treatment with alpha-mephe plus phe was attributable to hyperphenylalaninemia and the inhibition of tryptophan transport to the brain. Injection of tryptophan was found to restore the cerebral 5-HT level in the face of persistently severe hyperphenylalaninemia.

Post-traumatic stress disorder: evidence for diagnostic validity and methods of psychological assessment

Post-traumatic stress disorder (PTSD) is a diagnosis that has been the subject of considerable criticism in the clinical literature. Of primary concern has been the question of whether PTSD is a disorder that can be discriminated reliably from already existing diagnoses, such as depression, dysthymia, or generalized anxiety disorder. This paper reviews the evidence that surrounds this controversy and employs the guidelines for validating a diagnosis established by Robins and Guze (1970) as the framework for the review. A second purpose of this paper is to present a multiaxial approach for the assessment of PTSD. This approach includes the use of structured interviews, psychometrics, and a psychophysiological assessment procedure. Studies that support the reliability and validity of the components of the multiaxial method are reviewed.

Opposed locomotor asymmetries following lesions of the medial and lateral substantia nigra pars compacta or pars reticulata in the rat

In animals with lesions in the medial or lateral portions of the substantia nigra pars compacta (SNC) amphetamine produces circling in opposite directions. The present study examined the relationships between lesion site and the direction of circling using glyoxylic acid histofluorescence to visualize DA cells. Lesions were produced by 6-hydroxydopamine (2-6 micrograms) or 0.05% ascorbate injected into the SN. After lesions in the medial SNC, amphetamine caused rats to circle ipsiversive to the lesion while after lateral SNC lesions rats circled contraversively. When the lesion extended to the middle of the SNC, or deeper into the SN pars reticulata (SNR), the direction of circling was unpredictable. When the damage produced by the cannula track and ascorbate injection was in the lateral SNR animals circled ipsiversively while medial SNR damage led to contraversive circling. Thus the medial and lateral SN, and the pars compacta and pars reticulata, are functionally antagonistic. This four way division of the SN is consistent with the topographic mapping of SNC to striatum and striatum to SNR.

Concanavalin A binding induces association of possible mating-type receptors with the cytoskeleton in Tetrahymena

The lectin concanavalin A (conA; 25 micrograms/ml) inhibits conjugation in the ciliate Tetrahymena, and binds to receptors localized at the junction between conjugating cells. We report here that succinyl-conA (30 micrograms/ml) has similar activity, but that two other mannosespecific lectins, lentil and pea lectins, have inhibitory activities more than tenfold lower in this system, indicating that factors other than mannose specificity are essential for biological activity. By using fluorescein-isothiocyanate (FITC)-conA, we have found that extraction of cells with the detergent Triton X-100 removes conA receptors from the extraction-resistant cytoskeleton, but that the binding of conA to its receptor before extraction associates the ligand-receptor complex with the cytoskeleton. Under the hypothesis that the conA receptor may be a mating type receptor, we have used this ligand-induced differential cytoskeletal association, in conjunction with electrophoresis and Western blotting, to identify a glycoprotein with an apparent molecular weight (MW) of 23,000 D which may be a mating type receptor. Our data are consistent with a model in which a direct interaction between the conA receptor and the cytoskeleton, rather than receptor cross-linking, is the biologically significant activity of ligand binding.

Mechanical responses of developing Fisher rat heart. Effects of steroid hormone

Age-dependent changes in the mechanical responses of developing Fisher rat heart during the first three postnatal weeks were studied in relation to the hypothesis that the abnormality observed in the mechanical responses of the rat heart might be calcium related. Therefore the effect of frequency of stimulation as well as the response to calcium, epinephrine and ouabain on hearts of untreated and cortisol-treated rats was compared. The positive force-frequency response observed in fetal rat heart reverted to a highly negative response by the 12th to 14th postnatal day. The biphasic mechanical responses directly paralleled reported changes in circulating glucocorticoid levels in developing rat. The force-frequency response was maximally negative when the circulating levels of glucocorticoids were lowest. The reversion of the negative force-frequency responses coincided with a gradual increase reported in the circulating levels of glucocorticoids. The negative force-frequency response was absent in the cortisol-treated developing rat heart and a definite positive pattern was observed as the rats developed. A high sensitivity to free calcium concentration, seen in control fetal and and newborn hearts, diminished after the second postnatal week. By the third postnatal week, the sensitivity to high extracellular calcium concentrations was significantly reduced. The sensitivity to calcium persisted in the cortisol-treated hearts during the 3 postnatal weeks. Cortisol-treated hearts were more responsive to epinephrine than controls. The abbreviation of time to peak tension, a hallmark of the catecholamine effect, was observed at a younger age in the cortisol-treated hearts. Cortisol-treated hearts were more responsive to the inotropic effects of ouabain than controls. The possible involvement of glucocorticoids in the control of calcium handling elements of the myocardium is discussed.

Susceptibility of endothelial cells derived from different blood vessels to common viruses

We examined whether endothelial cells derived from different blood vessels vary in their susceptibility to viral infection. Five common viral pathogens of humans (herpes simplex 1, measles, mumps, echo 9, and coxsackie B4 viruses) were evaluated for growth in endothelial cells derived from bovine fetal pulmonary artery, thoracic aorta, and vena cava. All five viruses replicated in each type of endothelial cell. There were apparent differences in the quantities of measles and mumps viruses produced in pulmonary artery endothelium compared with thoracic aorta and vena cava when endothelial cells were obtained from different animals. However, when pulmonary artery endothelial cells were compared with vena cava cells from the same animal, growth of each virus was similar in the two cell types. Four of the viruses replicated in the various endothelial cells without producing appreciable changes in cell morphology. These results indicate that endothelial cells from different blood vessels are equally susceptible to the human viruses evaluated, and that viral replication can occur without major alterations in cell morphology. Endothelial cells could serve as permissive cells permitting viruses to leave the circulation and initiate infection in adjacent tissues, including subendothelial smooth muscle cells.

An assessment of verbal recall, recognition and fluency abilities in patients with Huntington's disease

Two investigations concerned with the memory deficits of patients with Huntington's Disease (HD) were performed. In the first experiment, early and advanced HD patients showed superior recognition memory than did alcoholic Korsakoff patients on modified recall and recognition forms of the Rey Auditory Verbal Learning Test. In contrast, on a letter fluency test (FAS) requiring the patients to search their semantic memories, both HD groups produced fewer correct words and perseveration errors than did the alcoholic Korsakoff group. In the second experiment, HD patients and Korsakoff patients were compared in their and recognition of short passages. While the HD and Korsakoff patients were equally impaired on recall tests, the HD patients evidenced significantly better recognition memory than did the amnesic group. As on the fluency test, the prose of the Korsakoff patients was characterized by intrusion (i.e., perseverative) errors. The results of the two experiments indicate that HD and Korsakoff patients' memory deficits are related to deficiencies in retrieval and an increased sensitivity to proactive interference, respectively.

Effects of in utero administration of phenobarbital on gamma-glutamyl transpeptidase

The present study was undertaken to determine the effects of the in utero administration of phenobarbital (Pb) on gamma glutamyl transpeptidase (gamma-GTP) in rats. Female Wistar rats were bred to healthy adult males. On day 1 of gestation (evidenced by spermatozoa from vaginal smear) the pregnant rats were given 100 mg/kg phenobarbital (as the sodium salt) daily via the BioServ Liquid diet throughout gestation. Pair-fed controls were given the same volume of food as consumed by the experimental group. The offspring were sacrificed at birth and body, brain and liver weights determined. The pups born to the Pb treated mothers weighed significantly less than those born to the control mothers (4.77 and 6.60 g respectively). The brains and livers were homogenized in Tris buffered saline and assayed for gamma-GTP activity. Brain gamma-GTP activity was found to be 0.00807 u in the Pb group and 0.00670 u in the control group. We also examined the effects of chronic administration of Pb in adult rats and found no apparent effect on liver or brain gamma-GTP activity.

Cloning an expressed gene shared by the human sex chromosomes

The existence of genes shared by mammalian sex chromosomes has been predicted on both evolutionary and functional grounds. However, the only experimental evidence for such genes in humans is the cell-surface antigen encoded by loci on the X and Y chromosomes (MIC2X and MIC2Y, respectively), which is recognized by the monoclonal antibody 12E7. Using the bacteriophage lambda gt11 expression system in Escherichia coli and immunoscreening techniques, we have isolated a cDNA clone whose primary product is recognized by 12E7. Southern blot analysis using somatic cell hybrids containing only the human X or Y chromosomes shows that the sequences reacting with the cDNA clone are localized to the sex chromosomes. In addition, the clone hybridizes to DNAs isolated from mouse cells that have been transfected with human DNA and selected for 12E7 expression on the fluorescence-activated cell sorter. We conclude that the cDNA clone encodes the 12E7 antigen, which is the primary product of the MIC2 loci. The clone was used to explore sequence homology between MIC2X and MIC2Y; these loci are closely related, if not identical.

The human Y chromosome

Despite its central role in sex determination, genetic analysis of the Y chromosome has been slow. This poor progress has been due to the paucity of available genetic markers. Whereas the X chromosome is known to include at least 100 functional genetic loci, only three or four loci have been ascribed to the Y chromosome and even the existence of several of these loci is controversial. Other factors limiting genetic analysis are the small size of the Y chromosome, which makes cytogenetic definition difficult, and the absence of extensive recombination. Based on cytogenetic observation and speculation, a working model of the Y chromosome has been proposed. In this classical model the Y chromosome is defined into subregions; an X-Y homologous meiotic pairing region encompassing most of the Y chromosome short arm and, perhaps, including a pseudoautosomal region of sex chromosome exchange; a pericentric region containing the sex determining gene or genes; and a long arm heterochromatic genetically inert region. The classical model has been supported by studies on the MIC2 loci, which encode a cell surface antigen defined by the monoclonal antibody 12E7. The X linked locus MIC2X, which escapes X inactivation, maps to the tip of the X chromosome short arm and the homologous locus MIC2Y maps to the Y chromosome short arm; in both cases, these loci are within the proposed meiotic pairing region. MIC2Y is the first biochemically defined, expressed locus to be found on the human Y chromosome. The proposed simplicity of the classical model has been challenged by recent molecular analysis of the Y chromosome. Using cloned probes, several groups have shown that a major part of the Y chromosome short arm is unlikely to be homologous to the X chromosome short arm. A substantial block of sequences of the short arm are homologous to sequences of the X chromosome long arm but well outside the pairing region. In addition, the short arm contains sequences shared with the Y chromosome long arm and sequences shared with autosomes. About two-thirds of XX males contain detectable Y derived sequences. As the amount of Y sequences present varies in different XX males, DNA from these subjects can be used to construct a map of the region around the sex determining gene. Assuming that XX males are usually caused by simple translocation, the sex determining genes cannot be located in the pericentric region. Although conventional genetic analysis of the Y chromosome is difficult, this chromosome is particularly suited to molecular analysis. Paradoxically, the Y chromosome may soon become the best defined human chromosome at the molecular level and may become the model for other chromosomes.

Isolation and characterization of an alphoid centromeric repeat family from the human Y chromosome

A collection of human Y-derived cosmid clones was screened with a plasmid insert containing a member of the human X chromosome alphoid repeat family, DXZ1. Two positive cosmids were isolated and the repeats they contained were investigated by Southern blotting, in situ hybridization and sequence analysis. On hybridization to human genomic DNAs, the expected cross-hybridization characteristic of all alphoid sequences was seen and, in addition, a 5500 base EcoRI fragment was found to be characteristic of a Y-specific alphoid repeat. Dosage experiments demonstrated that there are about 100 copies of this 5500 base EcoRI alphoid fragment on the Y chromosome. Studies utilizing DNA from human-mouse hybrids containing only portions of the Y chromosome and in situ hybridizations to chromosome spreads demonstrated the Y centromeric localization of the 5500 base repeat. Cross-hybridization to autosomes 13, 14 and 15 was also seen; however, these chromosomes lacked detectable copies of the 5500 base EcoRI repeat sequence arrangement. Sequence analysis of portions of the Y repeat and portions of the DXZ1 repeat demonstrated about 70% homology to each other and of each to the human consensus alphoid sequence. The 5500 base EcoRI fragment was not seen in gorilla, orangutan or chimpanzee male DNA.

Cytoskeletal reorganization and plasma membrane fusion in conjugating Tetrahymena

The conjugation junction of Tetrahymena is the specialized site where plasma membrane fusion occurs between two cells of complementary mating types. The junction is constructed through a series of cooperative interactions and morphogenetic steps. A contact-mediated interaction between free-swimming, sexually mature and mating-competent cells of two complementary mating types induces a morphological transformation of the anterior tips. Cells then join in pairs aligned by the apposition of their modified tips. Thin sections show that the plasma membranes of the tips are separated by approximately 500 A of extracellular space, in which some strands of matrix material can be identified. The cytoplasmic face of the membrane is in contact with a junction-specific thick layer of electron-dense material. At hundreds of independent sites in this junction plasma membranes fuse in a limited manner, thereby establishing hundreds of separate membrane-ensheathed cytoplasmic channels that connect the two cells. At the same locations the thick submembrane layer is interrupted. Consequently, the junction appears to be a structure that is perforated with hundreds of pores. This study poses the question of whether the junction's submembrane layer is, or includes, a skeletal element. Cells were extracted with the non-ionic detergent Triton X-100 under conditions that yield cytoskeletal frameworks (CFs) that maintain the morphological integrity of the cells. The CFs include chromatin and also cortical structures such as microtubule bands, basal bodies, ciliary axonemes, kinetodesmal fibres and fibrillar epiplasm. CFs of conjugant pairs are also paired, indicating that the junction contains a skeletal element that is responsible for integrating the individual CFs into a higher-order complex. At the ultrastructural level the skeletal structure of the junction includes membrane lamina and a submembrane scaffold, residues of the plasma membrane and thick submembrane layer, respectively, both of which are interrupted at the pores. However, the two separate scaffolds are joined at the rims of the pores. This provides a means by which the separate CFs become integrated. On the basis of images of junctional CFs, which show interruptions of the scaffold without concomitant membrane fusion, but where laminae are pressed close together, a specific model of membrane fusion is proposed. According to this model, the submembrane skeletal scaffold regulates membrane fusion by limiting its occurrence, and the extent of its occurrence.

Sorbitol/fructose metabolism in the lens

The function of the sorbitol pathway, both as a secondary energy source and as an osmotic counterbalancing force, was examined. Rat lenses were incubated in media containing fructose as the primary exogenous energy source, and 31P nuclear magnetic resonance (NMR) spectra were accumulated. Fructose was found to be a sub-optimal but usable substrate for glycolysis. The utilization of fructose was further confirmed by a 14C fructose tracer study, using high-pressure liquid chromatography. Thus the intralenticular pool of sorbitol + fructose could serve as a secondary energy source during severe hypoglycemia in the diabetic lens. However, fructose is not a physiologically significant alternative to glucose. 13C NMR spectroscopy was employed to determine the kinetics of sorbitol/fructose accumulation in lenses incubated in 35.5 mM 13C1-glucose, and the sorbitol/fructose consumption after the preincubated lenses were transferred to media containing no glucose. Based on these kinetic studies, we concluded that the sorbitol pathway cannot generate sorbitol/fructose fast enough to offset increased osmotic pressure from high glucose levels in the aqueous humor of the diabetic eye. The contribution of osmotic equivalents from sorbitol + fructose, however, cannot be ignored.

Validity and reproducibility of the Cooperative Cataract Research Group (CCRG) cataract classification system

The validity and reproducibility with which six classifiers [one experienced (L.T.C.), and five novices (W.G., F.G., W.W., J.W. and O.W.)] used the CCRG cataract classification system was assessed. The validity of index classifications was assessed by computing sensitivities and pairwise interclass correlations between experienced and novice classifiers using the former's classification as the standard. The number of unordered combinations of terms in the CCRG's classification was reduced by combining cortical terms according to the CCRG's accepted system of staged simplification. The number of combinations of terms at each stage is as follows: Stage I (greater than 1000); II (127); III (63); IV (15); V (7); VI and VII (3) and VIII (2). Excellent agreement was obtained between the experienced and novice classifiers for Stages VII and VIII of the classification, good agreement for Stages V and VI and poor agreement for Stages IV, III and II (sensitivities of 97, 96, 72, 59, 40, 24 and 20% respectively). Good agreement was also achieved for the classifications of single lenticular regions, except for subcapsular regions. The intra- and interobserver reproducibility was assessed by computing the Kappa statistic to (1) compare classifications between novice observers and (2) compare repeat classifications made by the same observer by viewing the same cataract once on each of three different days. The novice classifiers had excellent intraobserver reproducibility for Stages VII and VIII (Kappas of 0.87 and 0.97 respectively), good reproducibility for Stages IV, V and VI (Kappas of 0.53, 0.62 and 0.62, respectively) and marginal reproducibility for stages II and III (Kappas of 0.39 and 0.40, respectively). The intraobserver reproducibility of the experienced classifier was superior to the others for virtually all characteristics with excellent reproducibility for Stages IV, V, VI, VII and VIII with Kappas of 0.79, 0.90, 1.0, 1.0 and 1.0, respectively and good reproducibility for Stages II and III (Kappas of 0.55 and 0.64, respectively). These results indicate that the simplified CCRG cataract classification system (Stages IV-VIII) passes the minimum standards for reproducibility. The performance of the experienced classifier far exceeds the minimum standards and indicates the feasibility of improving classifier performance with training and practice.

Memory disorders associated with Huntington's disease: verbal recall, verbal recognition and procedural memory

Two experiments were conducted to evaluate the hypothesis that the memory disorders of Huntington's Disease (HD) patients are characterized by deficiencies in both retrieval mechanisms and the acquisition of procedural (skill-based) information. In the first study, verbal recall and recognition tests were administered to HD patients, amnesics and normal control (NC) subjects. Although the two patient groups were impaired relative to NC subjects on both recall and recognition of word lists, the performance of the HD patients was superior to that of the amnesics on the recognition test. In the second experiment early HD (EHD), advanced HD (AHD), amnesic and NC subjects were compared in the acquisition of the 'Tower of Hanoi' puzzle. Both the NC subjects and EHD patients acquired the solution of this puzzle after repeated trials, whereas the AHD and amnesic patients evidenced little improvement. However, on a recognition test assessing memory for facts about the puzzle, both the EHD and AHD patients were superior to the amnesic subjects. These results are consistent with the retrieval hypothesis but are equivocal with regard to the HD patients' proposed deficit in skill learning. Since the 'Tower' puzzle may rely heavily on both problem solving and skill learning capabilities, it may be of limited value in searching for double dissociations between patient groups and the acquisition of skill-based and data-based knowledge.

Cosmid clones derived from both euchromatic and heterochromatic regions of the human Y chromosome

Clones containing sequences derived from the human Y chromosome have been isolated from cosmid libraries of a human-mouse hybrid cell line. These libraries were constructed in the new expression vectors Homer V and Homer VI. The collection of cosmids isolated is enriched for unique sequence DNA and only a few of the cosmids contain the tandemly repeated sequences which constitute a major portion of the Y chromosome. Three cosmids have been studied in detail. One cosmid shows extensive homology over at least 20 kb with the long arm of the X chromosome; this homology is outside the predicted homology region required for sex chromosome pairing. The other two clones contain unique sequences specific to the Y chromosome and both map to the heterochromatic region of the Y chromosome long arm.

CT diagnosis of actinomycosis of the neck

Actinomycosis is an unusual bacterial infection that most often affects the head and neck region. Abscesses occasionally associated with a draining sinus may result secondary to extensive tissue destruction. We report the CT appearance in a case of actinomycosis of the neck. A thick walled enhancing mass with a low attenuation center was identified between the sternocleidomastoid muscle and the strap muscles of the neck. Enhancement of the adjacent muscles was present. Surgery confirmed an abscess with inflammation of the adjacent muscle. Histologic examination of the specimen showed the presence of multiple yellow (sulfur) granules containing Actinomyces. Computed tomography correctly determined the extent of the mass and lack of involvement of the deep structures of the neck.

Regional localization of 3 Y-derived sequences on the human X and Y chromosomes

The structure of the Y chromosome and the relationship between the human sex chromosomes have been studied using Y-derived sequences cloned in cosmids. Two probes recognize different unique sequences which map to the heterochromatic part of the long arm of the Y chromosome. A third sequence is shared by the long arm of the X chromosome and the euchromatic part of the Y chromosome. Thus homology between the sex chromosomes occurs outside the pairing region.

Histamine and slow reacting substance in acid-induced pneumonitis

Acid pneumonitis was produced in 18 dogs by the tracheal instillation of 3 ml/kg 0.1 N hydrochloric acid. Arterial and mixed venous oxygen tension, static compliance and pulmonary capillary wedge pressure were measured during a 2-hour observation period. Plasma histamine (measured by the enzymatic isotopic assay) increased from 1.7 +/- 0.2 ng/ml (mean +/- SE) before acid injury to 13.5 +/- 1.9 ng/ml after injury (p less than 0.05). In one group of 7 control dogs, 3 ml/kg of normal saline produced no increase in plasma histamine. Pulmonary edema secretions from acid injured animals had a histamine level of 30.3 +/- 3.8 ng/ml and slow reacting substance was detected in 7 of 11 animals. The slow reacting substance was an antihistamine-resistant, ethanol extractable substance that contracted guinea pig ileum. Lung weight-body weight ratio PaO2, and static compliance were different with acid pneumonitis compared to controls. Total protein was not different in the tracheal secretions compared to plasma. We conclude that histamine and slow reacting substance are released in this animal model of acid pneumonitis and may be important in the pathogenesis of the lung injury.

Mechanical properties of the plasma membrane of isolated plant protoplasts : mechanism of hyperosmotic and extracellular freezing injury

The volume of isolated protoplasts of rye (Secale cereale L. cv Puma) in a suspending solution at constant concentration is shown to be negligibly changed by tensions in the plasma membrane which approach that tension necessary to lyse them. This allows a detailed investigation of the plasma membrane stress-strain relation by micropipette aspiration.Over periods less than a second, the membrane behaves as an elastic two-dimensional fluid with an area modulus of elasticity of 230 millinewtons per meter. Over longer periods, the stress-strain relation approaches a surface energy law-the resting tension is independent of area and has a value of the order 100 micronewtons per meter. Over longer periods the untensioned area, which is defined as the area that would be occupied by the molecules in the membrane at any given time if the tension were zero, increases with time under large imposed tensions and decreases under sufficiently small tension. It is proposed that these long term responses are the result of exchange of material between the plane of the membrane and a reservoir of membrane material. The irreversibility of large contractions in area is demonstrated directly, and the behavior of protoplasts during osmotically induced cycles of contraction and expansion is explained in terms of the membrane stress-strain relation.

Elastic response of bilayers with intrinsic proteins

Intrinsic membrane proteins affect the ordering of neighbouring lipid chains. We have used a model of protein-lipid interactions in bilayers proposed by Owicki et al. (Owicki, J.C., Springgate, M.W. and McConnell, H.M. (1978) Proc. Natl. Acad. Sci. U.S.A. 75, 1616-1619) to show that near the lipid phase transition this effect may significantly increase the magnitude of a membrane's lateral compressibility (or correspondingly, decrease the magnitude of the membrane's elastic moduli).

Lateral tensions and pressures in membranes and lipid monolayers

The effects of lateral tension on the properties of membranes are often explained in comparison with analogous experiments on monolayers, which yield more detailed data. To calculate the effects of changes in tension on the composition of, or incorporation of amphiphiles into membranes we examine (i) the fidelity of the monolayer analogy, (ii) the range of possible tensions in a membrane, and the way in which tensions arise and (iii) the equilibrium partitioning of amphiphiles between aqueous solution and a bilayer under tension. We argue that, at the same areas per molecule, a monolayer at an n-alkane/water interface is a closer analogy of the lipid bilayer than a monolayer at an air/water interface. Next, we show from a thermodynamic argument that changes in membrane tension can affect the absorption of very large amphiphiles such as proteins, but that physiological tensions are unlikely to affect the absorption of lipids or drugs. Finally we consider the possibility that the measured bulk tension in a complicated membrane such as that of the erythrocyte may be larger than the local tension in the fluid mosaic portions, and suggest a model which explains the ability of the erythrocyte membrane to withstand much higher tensions than other biological membranes and lipid bilayers.

The stress-strain relation of the plasma membrane of isolated plant protoplasts

Over periods of up to a few seconds the plasma membrane of isolated rye protoplasts behaves elastically with an area modulus of 230 mN x m-1. Over longer periods, the area increases with time under large tension and decreases under sufficiently small tension, suggesting that material is incorporated into or depleted from the plane of the membrane.

Virus infection of endothelial cells

Endothelial injury is important in the pathogenesis of thrombosis, atherosclerosis, disseminated intravascular coagulation, and vasculitis. The ability of several common human viruses to infect cultures of endothelial cells obtained from human umbilical veins or bovine thoracic aorta was demonstrated. Indicators of infection included cytopathology, viral growth curves, and antigen detection by immunofluorescence. Herpes simplex virus type 1, adenovirus type 7, measles virus, and parainfluenza virus type 3 infected both human venous and bovine aorta endothelium. Mumps virus, poliovirus type 1, and echovirus type 9 grew only in human venous cells; coxsackievirus B4 infected only bovine arterial cultures; and cytomegalovirus, influenza A/Victoria/75 (H3N2) virus, and respiratory syncytial virus failed to grow in either cell culture. During replication some viruses caused acute lytic changes; some produced chronic, less destructive alterations; and other induced no apparent cytopathology. The results suggest that viral replication within endothelium may be important in the pathogenesis of viral disease of initiation of vessel-wall injury.

Clonal nature of the immune response to phosphocholine. IX. Heterogeneity among antibodies bearing M511 idiotypic determinants

A fraction of serum anti-PC antibodies from mice immunized with PC-KLH expresses idiotypic determinants of the PC-binding myeloma MOPC-511. We examined the molecular heterogeneity of IgG antibodies bearing the M511 idiotype (Id) by analytical isoelectric focusing followed by in situ labeling with 125I-anti-M511. Antibodies with the M511 Id were shown to be conserved in many mouse strains and were distinct from T15 Id+ anti-PC antibodies. Two complex sets of M511 Id+ bands were observed and these were identified as M511 Id+ antibodies belonging to the IgG1 and IgG3 subclasses. Examination of responses in different individuals of a strain permitted identification of at least 4 to 6 IEF band groups. Thus, the M511 Id is a marker for a family of closely related molecules. Quantitative variations were observed in the expression of the M511 family within a strain and between strains of mice that occurred independently of expression of the dominant T15 Id+ fraction. These results support the concept of an M511 Id family and further suggest that there can be differential control mechanisms governing expression of individual clones or a family of closely related clones.

Clonal nature of the immune response to phosphocholine. IX. Heterogeneity among antibodies bearing M511 idiotypic determinants

A fraction of serum anti-PC antibodies from mice immunized with PC-KLH expresses idiotypic determinants of the PC-binding myeloma MOPC-511. We examined the molecular heterogeneity of IgG antibodies bearing the M511 idiotype (Id) by analytical isoelectric focusing followed by in situ labeling with 125I-anti-M511. Antibodies with the M511 Id were shown to be conserved in many mouse strains and were distinct from T15 Id+ anti-PC antibodies. Two complex sets of M511 Id+ bands were observed and these were identified as M511 Id+ antibodies belonging to the IgG1 and IgG3 subclasses. Examination of responses in different individuals of a strain permitted identification of at least 4 to 6 IEF band groups. Thus, the M511 Id is a marker for a family of closely related molecules. Quantitative variations were observed in the expression of the M511 family within a strain and between strains of mice that occurred independently of expression of the dominant T15 Id+ fraction. These results support the concept of an M511 Id family and further suggest that there can be differential control mechanisms governing expression of individual clones or a family of closely related clones.

Long-term maintenance of Tetrahymena spp

Simple media for Tetrahymena, using rat gut or soybean as the nutrient source are described. Cultures can be maintained in these media up to one year at room temperature.

A possible skeletal substructure of the macronucleus of Tetrahymena

Upon removal of chromatin from isolated macronuclei of tetrahymena, residual structures are obtained, the organization of which faithfully reflects the distinctive architecture of the macronucleus. Macronuclei are isolated by a new procedure in which cells are lysed by immersion in citric acid and Triton X-100. This method is rapid and efficient and leaves the nuclear structures stripped of nuclear envelope and nucleoli. The remaining interconnected chromatin bodies are structurally differentiated into a dense outer shell and a fibrillar inner core. The fibrillar component is identified as chromatin because it is removed upon digestion with DNase and extraction with 2 M NaCl. The dense shell of the chromatin body is unaffected by the digestion procedure, which leaves a skeletal structure comprised of hollow spherical bodies. Analysis of the protein composition by SDS acrylamide gel electrophoresis before and after digestion with DNase and RNase and high-salt extraction shows that histones are diminished, whereas the nonhistone protein composition remains unchanged. It was found the DNase not only extracts chromatin but also protects the nonchromatin structure from the otherwise disruptive effects of high-salt extraction. The method used for isolating the nuclei also affects the structure remaining after the digestion procedure the citric acid/Triton X-100 method enhances the stability of the interconnected spherical bodies. The results indicate that the method for isolating nuclei and the procedure by which chromatin is extracted are both major factors contributing to the detection of a possible nonchromatin nuclear skeleton.

Mass selection of conditional mating mutants of Tetrahymena thermophila

The mating reaction in Tetrahymena thermophila includes a starvation period and two distinct cell interactions, co-stimulation and cell pairing, before the cells are cytoplasmically joined as conjugants. A selection procedure for harvesting mutants unable to mate at a restrictive temperature has been developed. A conjugant pair consisting of one cycloheximide-resistant cell and one wild-type cell (cycloheximide-sensitive) was itself sensitive to the drug. By adding cycloheximide and nutrient medium to a cross made at the restrictive and grow. Repetition of the selection procedure enriched for cells unable to conjugate at the restrictive temperature. The selected cells were able to grow at 38 degrees C and could conjugate at 28 degrees C. This procedure may be narrowed to select specifically for cell interaction mutants.