Synaptic processes and immune-related pathways implicated in Tourette syndrome

Tourette syndrome (TS) is a neuropsychiatric disorder of complex genetic architecture involving multiple interacting genes. Here, we sought to elucidate the pathways that underlie the neurobiology of the disorder through genome-wide analysis. We analyzed genome-wide genotypic data of 3581 individuals with TS and 7682 ancestry-matched controls and investigated associations of TS with sets of genes that are expressed in particular cell types and operate in specific neuronal and glial functions. We employed a self-contained, set-based association method (SBA) as well as a competitive gene set method (MAGMA) using individual-level genotype data to perform a comprehensive investigation of the biological background of TS. Our SBA analysis identified three significant gene sets after Bonferroni correction, implicating ligand-gated ion channel signaling, lymphocytic, and cell adhesion and transsynaptic signaling processes. MAGMA analysis further supported the involvement of the cell adhesion and trans-synaptic signaling gene set. The lymphocytic gene set was driven by variants in FLT3, raising an intriguing hypothesis for the involvement of a neuroinflammatory element in TS pathogenesis. The indications of involvement of ligand-gated ion channel signaling reinforce the role of GABA in TS, while the association of cell adhesion and trans-synaptic signaling gene set provides additional support for the role of adhesion molecules in neuropsychiatric disorders. This study reinforces previous findings but also provides new insights into the neurobiology of TS.

[Collected data on freehand technique instrumentation and literature comparison on fluoroscopic and CT-assisted navigation]

BACKGROUND

A proven and frequently used surgical procedure in patients with idiopathic scoliosis (IS) is posterior transpedicular corrective spondylodesis using the freehand technique. Novel procedures with fluoroscopically and computed tomography (CT)-assisted navigation are presumed to be less risky and more accurate.

OBJECTIVE

Is the freehand technique for IS safe with respect to screw-associated complications and intraoperative radiation exposure?

MATERIAL AND METHODS

Prospectively collected data (2017-2018) from 39 consecutive patients (average age 18.7 years) with thoracic single curvature IS (61.7° ± 13.9°) from a specialized scoliosis center were evaluated for the following parameters (mean ± standard deviation): total radiation product, fluoroscopy time, fused segments, operative time, blood loss and screw-associated complications. A comparison with data from the literature on intraoperative radiation exposure using navigation procedures was carried out.

RESULTS

The total radiation product per patient was 71.7 ± 44.0 cGy*cm², fluoroscopy time 17.4 ± 8.6 s. (7.8 segments), operative time 183.5 ± 54.2 min and blood loss 379.5 ± 183 ml. There were no screw-associated complications in the entire collective. Correction of the main curvature was 75.7%. Comparison of the data with index data from the literature showed a 1.25-12.5-fold higher radiation exposure for patients with fluoroscopically assisted navigation and 9.25-12.3-fold higher radiation exposure with CT-assisted procedures compared to the present results.

CONCLUSION

The results of this study showed that with appropriate experience freehand positioning of pedicle screws is associated with comparable accuracy and less radiation exposure for patients than navigation procedures. With respect to the young age of patients, a radiation-induced long-term risk for malignant diseases should be taken into consideration.

Interrogating the Genetic Determinants of Tourette's Syndrome and Other Tic Disorders Through Genome-Wide Association Studies

OBJECTIVE

Tourette's syndrome is polygenic and highly heritable. Genome-wide association study (GWAS) approaches are useful for interrogating the genetic architecture and determinants of Tourette's syndrome and other tic disorders. The authors conducted a GWAS meta-analysis and probed aggregated Tourette's syndrome polygenic risk to test whether Tourette's and related tic disorders have an underlying shared genetic etiology and whether Tourette's polygenic risk scores correlate with worst-ever tic severity and may represent a potential predictor of disease severity.

METHODS

GWAS meta-analysis, gene-based association, and genetic enrichment analyses were conducted in 4,819 Tourette's syndrome case subjects and 9,488 control subjects. Replication of top loci was conducted in an independent population-based sample (706 case subjects, 6,068 control subjects). Relationships between Tourette's polygenic risk scores (PRSs), other tic disorders, ascertainment, and tic severity were examined.

RESULTS

GWAS and gene-based analyses identified one genome-wide significant locus within FLT3 on chromosome 13, rs2504235, although this association was not replicated in the population-based sample. Genetic variants spanning evolutionarily conserved regions significantly explained 92.4% of Tourette's syndrome heritability. Tourette's-associated genes were significantly preferentially expressed in dorsolateral prefrontal cortex. Tourette's PRS significantly predicted both Tourette's syndrome and tic spectrum disorders status in the population-based sample. Tourette's PRS also significantly correlated with worst-ever tic severity and was higher in case subjects with a family history of tics than in simplex case subjects.

CONCLUSIONS

Modulation of gene expression through noncoding variants, particularly within cortico-striatal circuits, is implicated as a fundamental mechanism in Tourette's syndrome pathogenesis. At a genetic level, tic disorders represent a continuous spectrum of disease, supporting the unification of Tourette's syndrome and other tic disorders in future diagnostic schemata. Tourette's PRSs derived from sufficiently large samples may be useful in the future for predicting conversion of transient tics to chronic tic disorders, as well as tic persistence and lifetime tic severity.

Rare Copy Number Variants in NRXN1 and CNTN6 Increase Risk for Tourette Syndrome

Tourette syndrome (TS) is a model neuropsychiatric disorder thought to arise from abnormal development and/or maintenance of cortico-striato-thalamo-cortical circuits. TS is highly heritable, but its underlying genetic causes are still elusive, and no genome-wide significant loci have been discovered to date. We analyzed a European ancestry sample of 2,434 TS cases and 4,093 ancestry-matched controls for rare (< 1% frequency) copy-number variants (CNVs) using SNP microarray data. We observed an enrichment of global CNV burden that was prominent for large (> 1 Mb), singleton events (OR = 2.28, 95% CI [1.39-3.79], p = 1.2 × 10-3) and known, pathogenic CNVs (OR = 3.03 [1.85-5.07], p = 1.5 × 10-5). We also identified two individual, genome-wide significant loci, each conferring a substantial increase in TS risk (NRXN1 deletions, OR = 20.3, 95% CI [2.6-156.2]; CNTN6 duplications, OR = 10.1, 95% CI [2.3-45.4]). Approximately 1% of TS cases carry one of these CNVs, indicating that rare structural variation contributes significantly to the genetic architecture of TS.

Tourette Syndrome: a general pediatrician's 35-year experience at a single center with follow-up in adulthood

A retrospective analysis of a 35-year single-center experience with pediatric tics and Tourette syndrome was conducted. 482 charts from 1972 to 2007 were reviewed. Follow-up surveys were mailed to last known address and 83 patients responded (17%). Response rate was affected by long interval from last visit; contact information was often incorrect as it was the address of the patient as a child. Males constituted 84%. Mean tic onset was 6.6 years. At first visit, 83% had multiple motor tics and >50% had comorbidities. 44% required only 1 visit and 90% less than 12 visits. Follow-up showed positive clinical and social outcomes in 73/83 survey responses. Of those indicating a poor outcome, mean educational level was lower and attention deficit/hyperactivity disorder and learning disabilities were significantly higher. Access to knowledgeable caregivers was a problem for adult patients. A shortage of specialists may in part be addressed by interested general pediatricians.

Mapping the HLA ligandome landscape of acute myeloid leukemia: a targeted approach toward peptide-based immunotherapy

Identification of physiologically relevant peptide vaccine targets calls for the direct analysis of the entirety of naturally presented human leukocyte antigen (HLA) ligands, termed the HLA ligandome. In this study, we implemented this direct approach using immunoprecipitation and mass spectrometry to define acute myeloid leukemia (AML)-associated peptide vaccine targets. Mapping the HLA class I ligandomes of 15 AML patients and 35 healthy controls, more than 25 000 different naturally presented HLA ligands were identified. Target prioritization based on AML exclusivity and high presentation frequency in the AML cohort identified a panel of 132 LiTAAs (ligandome-derived tumor-associated antigens), and 341 corresponding HLA ligands (LiTAPs (ligandome-derived tumor-associated peptides)) represented subset independently in >20% of AML patients. Functional characterization of LiTAPs by interferon-γ ELISPOT (Enzyme-Linked ImmunoSpot) and intracellular cytokine staining confirmed AML-specific CD8(+) T-cell recognition. Of note, our platform identified HLA ligands representing several established AML-associated antigens (e.g. NPM1, MAGED1, PRTN3, MPO, WT1), but found 80% of them to be also represented in healthy control samples. Mapping of HLA class II ligandomes provided additional CD4(+) T-cell epitopes and potentially synergistic embedded HLA ligands, allowing for complementation of a multipeptide vaccine for the immunotherapy of AML.

Safety of the breast-feeding infant after maternal anesthesia

There has been an increase in breast-feeding supported by the recommendations of the American Academy of Pediatrics and the World Health Organization. An anesthesiologist may be presented with a well-motivated breast-feeding mother who wishes to breast-feed her infant in the perioperative period. Administration of anesthesia entails acute administration of drugs with potential for sedation and respiratory effects on the nursing infant. The short-term use of these drugs minimizes the possibility of these effects. The aim should be to minimize the use of narcotics and benzodiazepines, use shorter acting agents, use regional anesthesia where possible and avoid agents with active metabolites. Frequent clinical assessments of the nursing infant are important. Available literature does suggest that although the currently available anesthetic and analgesic drugs are transferred in the breast milk, the amounts transferred are almost always clinically insignificant and pose little or no risk to the nursing infant.

Analysis of acute pain scores and skin conductance measurements in infants

BACKGROUND

Skin conductance (SC) has been previously used to measure acute post-operative pain in adults and older children (>1year old).We have investigated the ability of SC to predict the severity of post-operative pain scores in the exclusively infant population.

METHODS

Infants (ages 6-12months) scheduled for elective surgery were recruited for the study. Data for behavioral pain scores and SC values - frequency of electrodermal responses per second (EDR/s), peak and basal levels, were recorded in the post-anesthesia care unit (PACU). Blood samples were collected for genomic studies, including single nucleotide polymorphisms (SNP) in morphine opioid receptor (MOR) A118G and the catechol-O-methyltransferase (COMT) G1947A genes.

RESULTS

31 infants, mean age 8.9months (±1.9); mean weight 8.5kg (±1.1) were included in the final study analysis. With every 0.1 unit increase in peak values noted on SC, the odds of higher pain scores were found to be 5% greater (p=0.03). For predictability of moderate to severe pain, the area under the curve, sensitivity and specificity were 0.64, 90.9% and 51.4% respectively for peak values and 0.66, 54.5% and 79.4% respectively for EDR/s values. Genotyping performed in 16 out of 31 infants demonstrated that the carriers of MOR 118G allele had consistently higher basal SC values in the PACU.

CONCLUSION

Peak SC values may serve as indicators of unmitigated pain. Further studies are needed to fully investigate the effect of MOR A118G SNP on the post operative pain scores and SC values in the larger infant population in order to validate both the clinical significance of the skin conductance for routine pain assessment in infants and the observed genetic effect.

The architectural transition of human complement component C9 to poly(C9)

Several regions of C9 including three cysteine-rich modules homologous to those in thrombospondin (TS), the low density lipoprotein receptor (LDL), the epidermal growth factors (EDGF), as well as two middle sections of the polypeptide chain were expressed in bacteria. Antibodies derived from these segments were used to probe the relative exposure of epitopes in C9 and poly(C9) using ELISAs. The results indicated that the TS and LDL modules are fully exposed in both monomer and polymer; however, the middle region of the polypeptide chain is buried in the monomer but external in the polymer. Using specified conditions, Fab fragments to the TS and LDL modules did not block C9 polymerization, but those to the middle region of the polypeptide chain and to some extent to the EDGF module did so. Immuno-electron microscopy of poly(C9) indicated that the C9 polypeptide chain assumes a 'U' shape, in which the TS and LDL modules are located on the upper rim. The EDGF module is located on the lower edge of the upper rim, and midsection of the polypeptide chain constructs the barrel of the tubule. Computer assisted contrast enhancement of select electron micrograph images of poly(C9) allowed the clear visualization of each subunit. These were seen to have a volute shape. The upper rim is composed of whorls that are apparently not in lateral contact. It is concluded that the TS and LDL modules do not participate directly in polymerization but cover the hydrophobic central region of the polypeptide chain in the monomer. As a consequence of circular polymerization the midsection of the polypeptide chain becomes exposed as each C9 lengths to fashion a volute form. reserved.

The efficacy and safety of miglitol therapy compared with glibenclamide in patients with NIDDM inadequately controlled by diet alone

OBJECTIVE

To compare the therapeutic effects of the alpha-glucosidase inhibitor miglitol (BAY m 1099), the sulfonylurea glibenclamide, and placebo on parameters of metabolic control and safety in patients with NIDDM that is inadequately controlled by diet alone.

RESEARCH DESIGN AND METHODS

After a 4-week placebo run-in period, 201 patients in 18 centers in 4 countries were randomized in a double-blind manner to miglitol (50 mg t.i.d., followed by 100 mg t.i.d.), glibenclamide (3.5 mg q.d/b.i.d.), or placebo for 24 weeks. Efficacy criteria were changes from baseline of HbA1c, fasting and postprandial blood glucose and insulin levels, body weight, and serum triglycerides.

RESULTS

Efficacy was assessed in 119 patients who completed the full protocol, and the results were similar to those obtained in 186 patients who fulfilled the validity criteria for analysis. Compared with placebo, mean baseline-adjusted HbA1c decreased by 0.75% (P = 0.0021) and 1.01% (P = 0.0001) in the miglitol and glibenclamide treatment groups, respectively. Blood glucose decreased slightly in the fasting state and considerably in the postprandial state in both treatment groups but not in the placebo group. Fasting insulin levels increased slightly (NS) in all treatment groups; however, postprandial insulin levels decreased with miglitol, while increasing markedly with glibenclamide (P = 0.0001 between all treatment groups). Gastrointestinal side effects (flatulence and diarrhea) occurred mostly in the miglitol-treated patients, while some glibenclamide-treated patients had symptoms suggestive of hypoglycemia.

CONCLUSIONS

Miglitol monotherapy is effective and safe in NIDDM patients. Compared with glibenclamide, it reduced HbA1c less effectively and caused more gastrointestinal side effects. On the other hand, glibenclamide, unlike miglitol, tended to cause hypoglycemia, hyperinsulinemia, and weight gain, which are not desirable in patients with NIDDM.

N-methyl-D-aspartate antagonists limit aminoglycoside antibiotic-induced hearing loss

The use of aminoglycoside antibiotics is limited by ototoxicity that can produce permanent hearing loss. We report that concurrent administration of N-methyl-D-aspartate (NMDA) antagonists markedly attenuates both the hearing loss and destruction of cochlear hair cells in guinea pigs treated with aminoglycoside antibiotics. These findings indicate that aminoglycoside-induced hearing loss is mediated, in part, through an excitotoxic process. The high correlation (Spearman correlation coefficient: 0.928; P < 0.01) obtained between the relative cochleotoxicities of a series of aminoglycosides in humans and the potencies of these compounds to produce a polyamine-like enhancement of [3H]dizocilpine binding to NMDA receptors is consistent with this hypothesis, and provides a simple in vitro assay that can predict this aspect of aminoglycoside-induced ototoxicity.

A continuous microtiter plate assay for screening nucleotide sugar-synthesizing nucleotidyltransferases

A continuous microtiter plate nucleotidyltransferase substrate screening assay (NUSSA) is described which allows the identification of nucleotide sugar-synthesizing enzyme activities. The assay is accomplished by the determination of the common product of these enzymes PPi with a PPi-dependent phosphofructokinase. A subsequent enzyme reaction cascade leads to the production of 2 mol NAD per mol PPi. PPi-dependent phosphofructokinase was purified from potato with respect to contaminating enzyme activities which would disturb NUSSA performance. NUSSA allows the quick, simultaneous, and comprehensive check of different sugar 1-phosphate and nucleoside triphosphate substrates using purified pyrophosphorylases or crude extracts of plants, microorganisms, and mammalian tissues. Moreover, NUSSA will assist to evaluate these enzymes for the synthesis of important nucleotide sugars which serve as substrates of glycosyltransferases in carbohydrate syntheses.

alpha 4 integrins mediate lymphocyte attachment and rolling under physiologic flow

Of the several families of adhesion receptors involved in leukocyte-endothelial cell interactions, only the selectins have been shown to initiate leukocyte interaction under physiologic shear; indeed, beta 2 (CD18) intergrins responsible for neutrophil arrest are unable to engage without prior selectin-mediated rolling. In contrast, alpha 4 (CD49d) integrins are shown here to initiate lymphocyte contract ("tethering") in vitro under shear and in the absence of a selectin contribution. The alpha 4 integrin ligands MAdCAM-1 and VCAM-1 support loose reversible interactions including rolling, as well as rapid sticking and arrest that is favored following integrin activation. Moreover, alpha 4 beta 7 mediates L-selectin (CD62L)-independent attachment of blood-borne lymphocytes to lamina propria venules in situ. Scanning electron microscopy of alpha 4 beta 7hi lymphoid cells reveals that, like L-selectin, alpha 4 beta 7 is highly concentrated on microvillous sites of initial cellular contact, whereas the beta 2 integrin LFA-1 is excluded from villi. Thus, alpha 4 but not beta 2 integrins can initiate leukocyte adhesion under flow, a capacity that may be in part a function of topographic presentation on microvilli.

Distinct but overlapping epitopes are involved in alpha 4 beta 7-mediated adhesion to vascular cell adhesion molecule-1, mucosal addressin-1, fibronectin, and lymphocyte aggregation

The mouse CD8+ T cell lymphoma TK1 expresses high levels of alpha 4 beta 7 integrin, which it can use to interact with multiple ligands including mucosal addressin-1 (MAdCAM-1), VCAM-1, and fibronectin. In addition, alpha 4 beta 7 can support TK1 cell aggregation. Here we have produced and characterized a panel of mAbs against alpha 4 beta 7 to define antigenic and functional epitopes associated with its distinct functions. One mAb, DATK32, is unique in recognizing an epitope specific to the alpha 4 beta 7 heterodimer. Furthermore, DATK32 induces TK1 cell aggregation yet inhibits TK1 cell adhesion to MAdCAM-1, VCAM-1, and fibronectin. Considered as a whole, the panel of anti-alpha 4 beta 7 mAbs studied define unique patterns of inhibition for alpha 4 beta 7 binding to each of its defined molecular ligands. We conclude that alpha 4 beta 7 interactions with MAdCAM-1, VCAM-1, and fibronectin can be modulated by Ab binding to distinct epitopes and thus probably involve functionally separable, although physically overlapping binding sites on this multifunctional integrin. These findings are consistent with the general observation that integrins use distinct, potentially differentially regulated interaction sites for adhesion to multiple ligands. Extension of these concepts to alpha 4 beta 7 has important considerations for understanding the roles of this integrin in lymphocyte homing to mucosal sites and in cell-cell interactions during the immune response.

Distinct but overlapping epitopes are involved in alpha 4 beta 7-mediated adhesion to vascular cell adhesion molecule-1, mucosal addressin-1, fibronectin, and lymphocyte aggregation

The mouse CD8+ T cell lymphoma TK1 expresses high levels of alpha 4 beta 7 integrin, which it can use to interact with multiple ligands including mucosal addressin-1 (MAdCAM-1), VCAM-1, and fibronectin. In addition, alpha 4 beta 7 can support TK1 cell aggregation. Here we have produced and characterized a panel of mAbs against alpha 4 beta 7 to define antigenic and functional epitopes associated with its distinct functions. One mAb, DATK32, is unique in recognizing an epitope specific to the alpha 4 beta 7 heterodimer. Furthermore, DATK32 induces TK1 cell aggregation yet inhibits TK1 cell adhesion to MAdCAM-1, VCAM-1, and fibronectin. Considered as a whole, the panel of anti-alpha 4 beta 7 mAbs studied define unique patterns of inhibition for alpha 4 beta 7 binding to each of its defined molecular ligands. We conclude that alpha 4 beta 7 interactions with MAdCAM-1, VCAM-1, and fibronectin can be modulated by Ab binding to distinct epitopes and thus probably involve functionally separable, although physically overlapping binding sites on this multifunctional integrin. These findings are consistent with the general observation that integrins use distinct, potentially differentially regulated interaction sites for adhesion to multiple ligands. Extension of these concepts to alpha 4 beta 7 has important considerations for understanding the roles of this integrin in lymphocyte homing to mucosal sites and in cell-cell interactions during the immune response.

L-selectin-mediated lymphocyte rolling on MAdCAM-1

The L-selectin, a cell surface C-type lectin, directs lymphocyte traffic to lymph nodes, and contributes to lymphocyte homing to Peyer's patches and to leukocyte interactions with inflamed venules. Here we report that the mucosal vascular addressin MAdCAM-1, a mucosal endothelial adhesion molecule with immunoglobulin- and mucin-like domains, is a facultative ligand for L-selectin. MAdCAM-1 isolated from mesenteric lymph nodes, but not from cultured endothelioma cells, bears N-glycanase-resistant sialic acid-containing carbohydrate which supports adhesion of L-selectin-transfected lymphoid cells under shear. Interacting lymphoid cells display a 'rolling' behaviour similar to the selectin-dependent rolling of neutrophils observed in inflamed venules. MAdCAM-1 is also a ligand for the lymphocyte integrin homing receptor for Peyer's patches, alpha 4 beta 7 (ref. 7), and may be uniquely adapted to support both selectin-mediated lymphocyte rolling and integrin-mediated adhesion and arrest in vivo.

Alpha 4 beta 7 integrin mediates lymphocyte binding to the mucosal vascular addressin MAdCAM-1

The mucosal vascular addressin, MAdCAM-1, is an immunoglobulin superfamily adhesion molecule for lymphocytes that is expressed by mucosal venules and helps direct lymphocyte traffic into Peyer's patches (PP) and the intestinal lamina propria. We demonstrate that the lymphocyte integrin alpha 4 beta 7, also implicated in homing to PP, is a receptor for MAdCAM-1. Certain antibodies to alpha 4 and beta 7 integrin chains but not to the beta 2 integrin LFA-1 inhibit lymphocyte binding to purified MAdCAM-1 and to MAdCAM-1 transfectants. Lymph node lymphocytes, alpha 4 beta 7+ TK1 lymphoma cells, and a beta 7-transfected variant of an alpha 4+ B cell line, 38C13, bind constitutively to MAdCAM-1. Binding is enhanced by Mn(++)-induced integrin activation. The related integrin alpha 4 beta 1 supports efficient binding to VCAM-1 but not to MAdCAM-1, even after integrin activation, indicating that MAdCAM-1 is a preferential ligand for alpha 4 beta 7. Alpha 4 beta 7 can also bind VCAM-1, but this requires greater integrin activation than binding to MAdCAM-1. The findings imply a selective role for the interaction of alpha 4 beta 7 and MAdCAM-1 lymphocyte in homing to mucosal sites.

Lymphocyte activation and regulation of three adhesion molecules with supposed function in homing: LECAM-1 (MEL-14 antigen), LPAM-1/2 (alpha 4-integrin) and CD44 (Pgp-1)

Directed migration of lymphocytes from blood into lymph nodes and gut-associated lymphatic tissue, also referred to as homing, is subject to change following activation. Lymphocyte migration into lymphoid organs in vivo and binding to high endothelial venules in vitro is largely suppressed after short-term stimulation with phorbol esters. The observed functional alterations were correlated with changes in the expression of three putative homing receptors, LECAM-1 (MEL-14 antigen), LPAM-1/2 (alpha 4-integrin) and the murine CD44 (Pgp-1, H-CAM, Hermes-antigen equivalent) upon different modes of cellular activation. Expression of LECAM-1 (gp90 MEL-14), a lymphocyte adhesion molecule implicated in targeting extravasation into lymph nodes, was found to be lost almost completely within minutes after protein kinase C activation. LECAM-1 re-expression occurred within less than 24 h. Rapid loss of LECAM-1 was also observed after calcium ionophores whereas anti-CD3 or concanavalin A elicited a gradual and heterogeneous loss of LECAM-1 becoming detectable after several hours only. A number of cytokines tested were not able to induce alterations in LECAM-1 expression. In contrast, expression of LPAM-1/2 (alpha 4-integrin) and CD44 (Pgp-1, H-CAM), two adhesion molecules supposed to direct extravasation into Peyer's patches, remained stable for hours after every stimulus tested; CD44 expression gradually increased 24 h after mitogenic activation, whereas a small reduction only was observed for the expression of the alpha 4-chain under certain conditions. Thus, reduced extravasation of lymphocytes into Peyer's patches after activation is not due to a decline in the surface density of LPAM-1/2 alpha-chain or CD44 whereas alterations in migration into lymph nodes parallel the expression of LECAM-1.

Lymphocyte activation and expression of the human leucocyte-endothelial cell adhesion molecule 1 (Leu-8/TQ1 antigen)

The Leu-8/TQ1 antigen, recently shown to be the human equivalent of the murine MEL-14 lymph node homing receptor and now designated as leucocyte-endothelial cell adhesion molecule, LECAM-1, has been used to dissect T, B and natural killer (NK) cells into various subpopulations with different functional properties, such as suppressor-inducer (CD4+ Leu-8/TQ1+) or helper (CD4+ Leu-8/TQ1-) T lymphocytes. Diminished Leu-8/TQ1 antigen density has been reported after lymphocyte activation with B- or T-cell specific stimuli for several days. In the present study, we sought to determine the signal requirements for altered Leu-8/TQ1 expression. Exposure of freshly isolated peripheral blood lymphocytes to phorbol 12-myristate 13-acetate (PMA) and/or calcium ionophores was found to cause rapid down-regulation of the Leu-8 antigen, with little or no Leu-8 reactivity remaining 1 hr after simultaneous addition of PMA and calcium ionophores to the culture medium. TQ1 reactivity was changed in parallel with that of Leu-8. Leu-8 expression of T and B cells was sensitive to both PMA and calcium ionophores, whereas Leu-8 expression of NK cells was affected by PMA but not by the calcium ionophore A23187. The effect of PMA on Leu-8/TQ1 expression could be antagonized by pretreatment with the protein kinase C inhibitor, H7, whereas that of A23187 could not. Partial re-expression of the Leu-8 antigen was seen 3 days after addition of PMA alone but not when it was given together with calcium ionophores. After Leu-8 down-regulation induced by 1 hr treatment with PMA or calcium ionophores. Leu-8 re-expression was observed within 24 hr when stimuli were removed by washing. Activation of T cells with anti-CD3 antibody resulted in a partial reduction of Leu-8/TQ1 expression, first detectable after 1-3 hr of stimulation and maximal at 24 hr. Fully mitogenmic concentrations of concanavalin A (Con A) did not affect Leu-8 expression within the first hours of culture. Transient reduction of Leu-8 expression was seen 24 hr after supraoptimal dosages of Con A, but Con A-stimulated lymphocytes cultured for 4-12 days with interleukin-2 (IL-2) retained Leu-8/TQ1 reactivity to a similar degree as fresh cells. In contrast to Leu-8/TQ1, CD45RA expression was not altered after 1 hr treatment with PMA and/or calcium ionophores but gradually disappeared during 1 week after Con A stimulation.(ABSTRACT TRUNCATED AT 400 WORDS)

Reactive perforating collagenosis and phototraumatism

Two pairs of siblings are reported suffering from reactive perforating collagenosis. The clinical features were recurrent crusted papules with a central keratinaceous plug. The plug was sometimes encircled by a narrow yellowish ring and a wider red ring, giving the appearance of a cockade. Lesions recurred spontaneously or were provoked by superficial injury to sun-exposed skin (phototraumatism). There were no other changes in the general health of these patients.

Fluorometric assay of bethanidine in plasma

A fluorometric method for determining bethanidine in blood plasma is described. The bethanidine is extracted into chloroform, a drug-dye complex with eosin Y is formed, and the fluorescence is measured (excitation, 535 nm; fluorescence, 560 nm). The assay detects 0.02 muM bethanidine (4 ng/ml) in plasma. The relative fluorescence of several body constituents and antihypertensive drugs is negligible. The plasma levels of bethanidine in four hypertensive patients receiving this drug were measured.

Diabetic scleredema

A special form of scleredema, confined to adults with severe and complicated diabetes mellitus, has come to be recognized. It lasts for an indefinite period of time, without tendency to spontaneous remission. The name diabetic scleredema is proposed for this form. Two such patients are presented and the literature on the subject is reviewed. We believe that diabetic scleredema should be added to the list of conditions complicating or in any way associated with diabetes mellitus.