A case of hereditary persistence of fetal hemoglobin caused by a gene not linked to the β-globin cluster

Summary The pattern of inheritance of several polymorphic restriction sites associated with the -gene cluster, and spanning a region of 52 kb, demonstrates that a determinant for hereditary persistence of fetal hemoglobin (HPFH) segregates independently from the non- globin gene cluster, as we postulated several years ago on purely genetical grounds. This finding provides additional evidence for the existence of diffusible factors affecting -chain expression. Moreover, we have identified a private HinccII polymorphism, in the vicinity of the gene in the family studied.     

Physicochemical and morphological characterization of two small polluted streams in southwest Germany

As a supporting component of the VALIMARproject, physicochemical investigations wereconducted monthly from 1995 to 1999 at theKrähenbach/Aich stream system (two samplingsites) and at the Körsch stream (sixsampling sites). Several physicochemicalparameters were analysed continuously bydataloggers during the entire sampling period.Moreover, a selection of the most importantmorphological parameters of the stream wererecorded in 1998.The results of these physicochemicalinvestigations demonstrated that theKrähenbach/Aich system could becharacterized as a natural rhithral submontanecarbonate stream system that is welloxygenated. Low temporal variations in pH,conductivity and chloride occurred at allsampling sites in the Krähenbach whichcoincided with the geological conditions atthis test stream. Because of relatively lowconcentrations of organic and inorganiccompounds during the entire study period thesites AB and AC in the Krähenbach/Aichsystem were classified as slightly polluted.The morphological assessment of the streamindicated a moderately affected status atboth of these streams.Physicochemical and morphologicalinvestigations along the Körsch streamsystem (KA to KE including the tributary streamSulzbach) indicated a highly affected rhithralsubmontane carbonate system characterized byhigh water velocity, flow rate and dissolvedoxygen. The Körsch, however, differssignificantly with respect to watertemperature, conductivity, pH, BOD₅,nutrients, and chloride concentrations from theKrähenbach. As a result of differentanthropogenic inputs (e.g. several sewageplants, agriculture activities and waste waterdumping) the Körsch sites KA to KD wereclassified as critically to heavilypolluted. The morphological assessmentindicated a clearly affected to damagedstatus. The upstream site KE could becharacterized as slightly polluted and itsmorphological structure as moderatelyaffected.     

Endocrine cells in the human fetal small intestine

Summary In this report we describe the time of appearance and ultrastructural features of enteroendocrine cells (EECs) in the human fetal small intestine (SB) between 9 and 22 weeks gestation. Thirteen distinctive EECs were identified in fetal SB. Two of these, not found in normal adult SB, appeared within the stratified epithelium of the proximal SB at 9–10 weeks. They were arbitrarily termed primitive and precursor cells. As in all fetal EECs, the pale cytoplasm of the primitive cell contains a distinctive population of secretory granules (SGs). Primitive cell SGs average 200–330 nm; some have dense cores with lucent halos while others are filled with a homogeneous dense or flocculent material. The SGs of the precursor cells are larger, averaging up to 1 m in diameter and their contents vary in electron density. A third group of cells not described in normal adult SB was arbitrarily termed transitional cells. These have two populations of SGs; one resembles the SGs of the precursor cells, and the other resembles the SGs of some of the specific adult type EECs. Transitional EC, S, I and G cells are seen. In addition, mature appearing EC, S, G, I, L, D, and D₁ cells were identified by 12 weeks of gestation. The primitive, precursor, and transitional cells may represent sequential developmental precursors of adult type EECs.Supported by Research Grant AM-17537 from the National Institutes of Health, Besthesda, MarylandThe authors would like to thank Ms. Linda Barstein for her excellent technical assistance     

Structural studies of the glycopeptides of B-chain of cinnamomin – a type II ribosome-inactivating protein by nuclear magnetic resonance

Cinnamomin is a plant type II ribosome-inactivating protein (RIP) isolated from the seeds of Cinnamomum camphora. It consists of two nonidentical polypeptide chains (A- and B-chain) held together through one disulfide linkage. Its A- and B-chain contain 0.3% and 3.9% sugars respectively. The B-chain of cinnamomin was digested by pronase E and then the liberated glycopeptides were separated from non-glycopeptides by gel filtration chromatography on a Bio-Gel P-4 column. Three crude glycopeptides were obtained by continuing chromatography over anion-exchange resin (AG1-X2) in the buffer of 2% pyridine-acetic acid (pH 8.3) with a polygradient elution system. Through further purification by the gel filtration chromatography and HPLC, three major glycopeptides, GP1, GP2 and GP3 were obtained. Mainly by two-dimensional Nuclear Magnetic Resonance (NMR) including TOCSY, DQF-COSY, NOESY, HMQC and HMBC, their primary structures were analyzed as: Man1,3Man1,6(Man1,3)(Xyl1,2)Man1,4GlcNAc1,4GlcNAc1-(Gly-)Asn-Asn-Thr(GP1), Man1,6(Man1,3)(Xyl1,2)Man1,4GlcNAc1,4(Fuc1,3)GlcNAc1-Asn-Ala-Thr(GP2),Man1,6(Man1,3)Man1,6(Man1,2 Man1,3)Man1,4GlcNAc1,4GlcNAc1-(Ala-)Asn-Gly-Thr(GP3).     

Role of mitochondria in ethanol tolerance of Saccharomyces cerevisiae

The presence of active mitochondria and oxidative metabolism is shown to be essential to maintain low inhibition levels by ethanol of the growth rate (), fermentation rate (v) or respiration rate () of Saccharomyces cerevisiae wild type strain S288C. Cells which have respiratory metabolism show K _i (ethanol inhibition constant) values for , v and , higher (K _i>1 M) than those of petite mutants or grande strains grown in anaerobiosis (K _i=0.7 M). In addition, the relationship between or v and ethanol concentration is linear in cells with respiratory metabolism and exponential in cells lacking respiration. When functional mitochondria are transferred to petite mutants, the resulting strain shows K _i values similar to those of the grande strain and the inhibition of and v by increasing ethanol concentrations becomes linear.     

Die Hemmung der Phytochrominduzierten Photomorphogenese („Positive” Photomorphosen) des Senfkeimlings (Sinapis alba L.) Durch Actinomycin D und Puromycin

Zusammenfassung Die positiven Photomorphosen Öffnung des Hypokotylhakens und Entfaltung der Kotyledonen können ganz ähnlich wie die phytochrominduzierte Anthocyansynthese und andere positive Photomorphosen durch Actinomycin D und Puromycin gehemmt werden. Man kann daraus schließen, daß diese beiden photomorphogenetischen Reaktionen des Senfkeimlings ebenfalls durch eine von P₇₃₀ über eine Signalkette ausgelöste Aktivierung von potentiell aktiven Genen veranlaßt werden.

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The inhibition of phytochrome-mediated photomorphogenesis (positive photoresponses) by actinomycin D and puromycin in the mustard seedling (Sinapis alba L.)

Summary The many photochrome-mediated photoresponses of a seedling (Sinapis alba L., white seeded mustard) can be divided into 3 categories: positive, negative, and complex photoresponses. Positive photoresponses are those which are characterized by an initiation or a promotion of biosynthetic or growth processes (Mohr, 1966b). Phytochrome-mediated anthocyanin synthesis is the prototype of a positive photoresponse. It has been shown in previous papers (e.g. Lange and Mohr, 1965; Mohr et al., 1965) that positive photoresponses can be specifically inhibited by actinomycin D and puromycin. It has been concluded that in the case of positive photoresponses P₇₃₀ (the active phytochrome) exerts its function through differential gene activation.—In the present paper it has been demonstrated that phytochrome-mediated positive photoresponses of the mustard seedling like opening of the hypocotylar hook and unfolding of the cotyledons can be inhibited by relatively low doses of actinomycin D and puromycin in very much the same way as anthocyanin synthesis or cotyledon enlargement is inhibited. It has been concluded that in these cases too the action of P₇₃₀ must be attributed to an activation of potentially active genes in the manner postulated on the basis of the data on anthocyanin synthesis.

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Die Arbeit wurde durch Sachbeihilfen der Deutschen Forschungsgemeinschaft und der Stiftung Volkswagenwerk (an Prof. Mohr) ermöglicht.     

Proteolysis alters the spectral properties of 124 kdalton phytochrome from Avena

Native phytochrome from Avena sativa L. is homogeneous with a monomeric molecular weight of 124 kdalton; 6–10 kdalton larger than the heterogeneous 120 kdalton preparations previously considered to be undegraded (Vierstra and Quail, 1982, Proc. Natl. Acad. Sci. USA, 79: 5272–5276). The phototransformation difference spectrum (Pr-Pfr) of 124 kdalton phytochrome measured in crude extracts has a minimum in the farred region at 730 nm, the same as that observed in vivo. These spectral properties contrast with those of 120 kdalton phytochrome purified by column immunoaffinity chromatography where the difference minimum is at 724 nm. When 124 kdalton phytochrome is incubated as Pr in crude extracts, the difference minimum shifts progressively to shorter wavelengths (from 730 to 722 nm) concomitant with the proteolytic degradation of the chromoprotein to the mixture of 118 and 114 kdalton species that comprise 120 kdalton phytochrome preparations. These two effects are inhibited in concert by the serine protease inhibitor, phenylmethylsulfonylfluoride, and or maintenance of the phytochrome in the Pfr form. These results provide further evidence that 124 kdalton phytochrome is the native molecule in Avena and indicate that the peptide segments removed by proteolysis of the Pr form are important to the pigment's spectral integrity. The present data thus resolve the previously unsettled question of why the Pfr form of 120 kdalton phytochrome isolated by various procedures from Avena has been found to absorb at shorter wavelengths than that observed in vivo. Previous spectral studies with 120 kdalton phytochrome preparations are open to reexamination.Abbreviations, symbols PMSF phenylmethylsulfonylfluoride - SDS-PAGE sodium dodecyl sulfate polyacrylamide gel electrophoresis - Ig immunoglobulin - A_minimum, A_maximum phototransformation difference spectrum (Pr-Pfr) minimum and maximum - A_r/A_fr ratio spectral change ratio     

Comparative Study of Effects of Various Sterols and Triterpenoids on Permeability of Model Lipid Membranes

Using permeability to labeled glucose as a criterion of stability for liposomal membranes, a comparative study on stabilizing properties of different sterols and triterpenes in phospholipid bilayer has been carried out as well as on structural peculiarities of sterols responsible for membranolytic properties of cucumarioside G₁ from the cucumaria Eupentacta fraudatris. Stabilizing action of the studied sterols and triterpenoides incorporated in the bilayer decreases in the following order: cholesterol sulfate > cholesterol > ⁵-sterols > -sitosterol > ergosterols > ⁷-sterols > epicholesterol > pregnane > androstane > coprosterol > 14-methylcholest-9(11)-en-3-ol > 4, 14-dimethylcholest-9(11)-en-3-ol > holothurinogenin A₁ > glucoside of cholesterol > -xylosidase of ⁷-sterols > betulin > protopanaxatriol > phosphatidylcholine liposomes without sterol > protopanaxadiol > oleanolic acid. Sterol-dependent membranolytic cucumarioside G₁ practically loses its ability to increase permeability of phospholipid membranes containing sterols obtained from this holothuria as well as coprosterol, epicholestrol, sulfated and glycosylated forms of sterols. The obtained results confirm the sterol hypothesis of the mechanism of membranotropic action of holothuria glycosides and of resistance to them of holothuria cell membranes.     

Homocysteine stimulates the expression of monocyte chemoattractant protein-1 in endothelial cells leading to enhanced monocyte chemotaxis

The effect of intraperitoneal administration of tocopherol (100 mg/kg wt/24 h) on ascorbate (0.4 mM) induced lipid peroxidation of mitochondria and microsomes isolated from rat liver and testis was studied. Special attention was paid to the changes produced on the highly polyunsaturated fatty acids C20:4 n6 and C22:6 n3 in liver and C20:4 n6 and C22:5 n6 in testis. The lipid peroxidation of liver mitochondria or microsomes produced a significant decrease of C20:4 n6 and C22:6 n3 in the control group, whereas changes in the fatty acid composition of the tocopherol treated group were not observed. The light emission was significantly higher in the control than in the tocopherol treated group. The lipid peroxidation of testis microsomes isolated from the tocopherol group produced a significant decrease of C20:4 n6 , C22:5 n6 and C22:6 n3, these changes were not observed in testis mitochondria. The light emission of both groups was similar. The treatment with tocopherol at the dose and times indicated showed a protector effect on the polyunsaturated fatty acids of liver mitochondria, microsomes and testis mitochondria, whereas those fatty acids situated in testis microsomes were not protected during non enzymatic ascorbateFe²⁺ lipid peroxidation. The protector effect observed by tocopherol treatment in the fatty acid composition of rat testis mitochondria but not in microsomes could be explained if we consider that the sum of C20:4 n6 + C22:5 n6 in testis microsomes is 2-fold than that present in mitochondria.     

Structural and functional properties of proteasome activator PA28

The proteasome activator PA28 or 11S regulator is a protein complex composed of two different but homologous polypeptides, termed PA28 and PA28. The purified activator protein (_200 kDa) is a ring-shaped heteromultimer containing the two polypeptides, possibly with an _{3 3} stoichiometry. The activator, which by itself shows no hydrolytic activity elicits activation of the proteasome's multiple peptidase activities by binding to the terminal rings of the proteinase. In vitro, active PA28 can be reconstituted from isolated and subunits, yielding two different oligomers: with the single subunit, PA28 homomultimers with moderate stimulatory activity toward 20S proteasomes are obtained whereas isolated -subunits are unable to form oligomers and are devoid of stimulatory activity. However, in the presence of both subunits, heteromultimers form, concomitant with restoration of full stimulatory activity. The recent finding that PA28 modulates the proteasome-catalyzed production of antigenic peptides presented to the immune system on MHC class I molecules indicates a cellular function of the activator in antigen processing. Abbreviations: IFN – interferon; LMP – low molecular weight peptide; MHC – major histocompatibility complex.     

Mechanism of gene conversion in Ascobolus immersus. II. The relationships between the genetic alterations in b 1 or b 2 mutants and their conversion spectrum

Summary In order to establish a relationship between the type of genetic alteration occurring in the mutant and the conversion spectrum which is associated with it, an attempt was made to characterize the genetic alterations in a sample of five spore colour mutants by specific reversion.All the mutants revert by back-mutation. Reversion of one of them is possible by mutation in external suppressor gene: at least two of the external suppressors behave like super-suppressors. Reversion of two other mutants by intragenic second-site mutation and study of the intragenic suppressors indicate that they are of the frameshift type. One of the frameshift mutants (ICR₁₇₀ induced) reverts by two alkylating agents suggesting that it originates from base(s) addition. The inhability of ICR₁₇₀ to induce reversion of this mutant suggests the preferential occurrence of base addition in ICR₁₇₀ mutagenesis. Conversly the other frameshift mutant (induced by ethyl methanesulfonate) reverts strongly by ICR₁₇₀. Thus it is concluded that it originates from deletion.These two frameshift mutants and all the ICR₁₇₀ induced mutants give no or very few asci with postmeiotic segregation and either an excess of conversion towards the mutant type allele (addition type mutant) or towards the wild type allele (deletion type mutant).Evidence supports the hypothesis that mutants which give many asci with postmeiotic segregation originate from substitution.These data imply differential recognition of non-pairing and mispairing of bases and in the case of non-pairing, that the direction of conversion is determined by the non-pairing itself.     

Solution conformations of proline rings in proteins studied by NMR spectroscopy

Summary Three different conformations of proline rings in a protein in solution, Up, Down and Twist, have been distinguished, and stereospecific assignments of the pyrrolidine -, - and -hydrogens have been made on the basis of ¹H-¹H vicinal coupling constant patterns and intraresidue NOEs. For all three conformations, interhydrogen distances in the pairs -³, ³-³, ²-², ²-², and ³-³ (2.3 Å) are shorter than those in the pairs -², ²-³, ³-², ²-³, and ³-² (2.7–3.0 Å), resulting in stronger NOESY cross peaks. For the Up conformation, the ³-² and ²-³ spin-spin coupling constants are small (<3 Hz), and weak cross peaks are obtained in a short-mixing-time (10 ms) TOCSY spectrum; all other vicinal coupling constants are in the range 5–12 Hz, and result in medium to strong TOCSY cross peaks. For the Down form, the -², ²-³, and ³-² vicinal coupling constants are small, leading to weak TOCSY cross peaks; all other couplings again are in the range 5–12 Hz, and result in medium to strong TOCSY cross peaks. In the case of a Twist conformation, dynamically averaged coupling constants are anticipated. The procedure has been applied to bovine pancreatic trypsin inhibitor and Cucurbita maxima trypsin inhibitor-V, and ring conformations of all prolines in the two proteins have been determined.     

Inhibition of protein synthesis enhances the lytic effects of tumor necrosis factor α and interferon γ in cell lines derived from gynecological malignancies

Summary Few clinical responses have occurred in preliminary studies using the cytokines tumor necrosis factor (TNF) or interferon (IFN) in cancer patients. This may be related to the observation that many malignant cell lines are resistant to lysis by these cytokinesin vitro. Resistance to lysis by TNF or IFN in many cells is controlled by a protein-synthesis-dependent mechanism, such that when protein synthesis is inhibited cells become sensitive to lysis by these cytokines. Because there is some evidence that TNF and IFN act through different lytic mechanisms and are opposed by different resistance mechanisms, we treated a panel of eight cell lines, five derived from human cervical carcinomas (ME-180, MS751, SiHa, HT-3, and C-33A) and three derived from ovarian carcinomas (Caov-3, SK-OV-3, and NIH: OVCAR-3) with both TNF and IFN to determine whether such combination treatment might maximizein vitro cell lysis. Our results showed that pretreatment with IFN followed by exposure to TNF in the presence of protein synthesis inhibitors increased lysis of seven of the eight cell lines above that seen with either TNF or IFN and inhibitors of protein synthesis. Only the cell line C-33A was resistant to lysis by TNF and IFN, when exposed to these agents both alone and in combination with protein synthesis inhibitors. Clinically, combining the cytokines TNF and IFN with protein synthesis inhibitors may maximize thein vivo lytic effects of these cytokines.Supported by American Cancer Society Career Development Award 90-221     

Isolation of α and β Brain Tubulin Subunits after Alkaline Treatment of the Protein

We demonstrate here that brain purified tubulin can be dissociated into and subunits at pH > 10 and that the subunits can be separated by using the Triton X-114 phase separation system. After phase partition at pH > 10, tubulin but not tubulin behaves as a hydrophobic compound appearing in the detergent rich phase. After three extractions of the alkaline aqueous phase with Triton X-114, about 90% of the tubulin was recovered in the detergent rich phase. The hydrophobic behavior observed for tubulin after its dissociation at pH 11.5 was not due to an irreversible change of the protein, because when the detergent rich phase containing tubulin was diluted with a buffer solution at pH 7.3 and the solution allowed to partition again, -tubulin is recovered in the aqueous phase. The detergent in the aqueous phase of the and tubulin preparations can be removed up to 90% by 12 h dialysis. The and subunits of tubulin from kidney and liver behave, in this phase separation system, like those of brain tubulin.     

The human complement component C8B gene: structure and phylogenetic relationship

The eighth component of human complement (C8) is a serum protein that consists of three chains (, and ), encoded by three separate genes, viz., C8A, C8B, and C8G. In serum, the -subunit is non-covalently bound to the disulfide-linked - subunit. Using a full-length C8 cDNA probe, we isolated several clones from human genomic DNA libraries. Four clones covering the complete cDNA sequence were characterized by TaqI restriction mapping and were shotgun subcloned into M13. C8-cDNA-positive clones were partially sequenced to characterize the 12 exons of the gene with sizes from 69 to 347 bp. All intron-exon junctions followed the GT-AG rule. By using polymerase chain reaction (PCR) primers located in the adjacent intron sequences, all 12 exons of the C8B gene could be amplified from genomic DNA. All fragments showed the expected sizes. The sizes of eight introns could be determined by using primer pairs that amplified two exons and the enclosed intron, and by restriction mapping. These analyses and the insert sizes of the genomic clones indicate that the C8B gene has a total size of approximately 40 kb. The polymorphic TaqI site of the C8B gene localized in intron 11 could be demonstrated by direct restriction fragment analysis of a PCR fragment containing exons 11 and 12, and the enclosed intron 11. Homology comparison of the C8B gene with C8A and C9 on the basis of the exon structure confirmed the ancestral relationship known from the protein level.     

Kinetic properties of bovine brain proteinl-isoaspartyl methyltransferase determined using a synthetic isoaspartyl peptide substrate

Proteinl-isoaspartyl methyltransferase, an enzyme enriched in brain, is implicated in the repair of age-damaged proteins containing atypical, isoaspartyl peptide bonds. We have investigated the kinetics of methylation using a synthetic peptide substrate having the structure Trp-Ala-Gly-Gly-isoAsp-Ala-Ser-Gly-Glu. Double-reciprocal plots of initial velocity versus concentration of S-adenosylmethionine (AdoMet) at different fixed concentrations of peptide gave straight lines converging at a positive 1/v value and a negative 1/AdoMet value. The product S-adenosylhomocysteine (AdoHcy) was a competitive inhibitor towards AdoMet and a linear mixed-type inhibitor towards peptide. These results are consistent with the rapid-equilibrium random sequential bi-bi mechanism previously proposed for the enzyme, but they also reveal the formation of the deadend, enzyme-peptide-AdoHcy, complex. The rate constants were:V _max=32–34 nmol/min/mg,K ^peptide=7.6–9.4 M,K ^AdoMet=1.9–2.2 M, =0.43–0.53,K ^AdoHcy=0.08 M, =2.9. The interaction factors and indicate that binding of enzyme to peptide increases its affinity for AdoMet and decreases its affinity for AdoHcy. Methylation was linear with time throughout the transfer of 2 mol of methyl groups/mol of enzyme. This absence of burst kinetics suggests that slow release of products cannot explain the low turnover number.Special issue dedicated to Dr. Paul Greengard     

Histochemical studies on the distribution of β-glucuronidase and succinic dehydrogenase in young and old spinal ganglion cells of the rat

Summary The present study compares the distribution of -glucuronidase and succinic dehydrogenase in young and old spinal ganglion cells of rat. In young cells there are indications of cyclic activity of these enzymes, i.e., in some stages there are perinuclear concentrations of the enzymes, at other times -glucuronidase and succinic dehydrogenase are uniformly distributed throughout the cytoplasm. These stages have been discussed with the identical distribution of mitochondria. However, in old spinal ganglion cells both -glucuronidase and succinic dehydrogenase become mainly concentrated in the pigment areas, suggesting thereby their possible role in the production of pigment, through the medium of the mitochondria.     

Cholinesterases and cell proliferation in “nonstratified” and “stratified” cell aggregates from chicken retina and tectum

Summary Dissociated single cells from chicken retina or tectum kept in rotation-mediated cell culture aggregate, proliferate and establish a certain degree of histotypical cellto-cell relationships (sorting out), but these systems never form highly laminated aggregates (nonstratified R- and T-aggregates). In contrast, a mixture of retinal plus pigment epithelial cells forms highly stratified aggregates (RPE-aggregates, see Vollmer et al. 1984). The present comparative study of stratified and nonstratified aggregates enables us to investigate the process of cell proliferation uncoupled from that of tissue stratification. Here we try to relate these two basic neurogenetic processes with patterns of expression of cholinesterases (AChE, BChE) during formation of both types of aggregates.During early aggregate formation, in both stratified and nonstratified aggregates an increased butyrylcholinesterase activity is observed close to mitotically active cells. Quantitatively both phenomena show their maxima after 2–3 days in culture. In contrast, AChE-expression in all systems increases with incubation time. In nonproliferative areas, in the center of RPE-aggregates, the formation of plexiform layers is characterized initially by weak BChE and then strong AChE-activity. These areas correspond with the inner (IPL) and outer (OPL) plexiform layers of the retina in vivo. Although by sucrose gradient centrifugation we find that the 6S- and the fiber-associated 11S-molecules of AChE are present in all types of aggregates, during the culture period the ratio of 11S/6S-forms increases only in RPE-aggregates, which again indicates the advanced degree of differentiation within these aggregates.It is thus demonstrated that cholinesterases first correlate with neuronal cell proliferation and later with stratification, which indicates functions of both enzymes during both developmental periods.Abbreviations AChE acetylcholinesterase - BChE butyrylcholinesterase - iso-OMPA specific inhibitor of BChE - BW 284C51 specific inhibitor of AChE - IPL inner plexiform layer - OPL outer plexiform layer     

Intranuclear inclusions in pericytes of the hypothalamus of the rat

Summary This paper deals with the ultrastructure of two types of intranuclear inclusions, nuclear bodies and membranous lamellar bodies, present in hypothalamic pericytes of intact adult rats. The nuclear bodies exhibited simple and granular forms, whereas the membranous lamellar bodies were entirely made up of myelin-like membrane whorls.The occurrence of these bodies in nuclei of pericytes has never been previously reported. The origin and functional meaning of such structures is discussed in the light of recent ultrastructural and biochemical studies on nuclear inclusions.