Relations between Meckel's cartilage and the morphogenesis of the mandible in the human embryo

Summary Based on a series of human embryos classified in stages [28], the authors studied the evolution of Meckel's cartilage in its ventral portion and its relations to the morphogenesis of the mandible. Three stages appeared particularly important: stage 16, appearance of Meckel's cartilage; stage 20, beginning of membranous ossification; and stage 23, end of the embryonic period (8th week). The primitive bony nodule which develops from the embryonic mesenchyme appears as a double bony layer forming a groove containing the neurovascular bundle, into which the dental lamina is also invaginated.

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Relations entre le cartilage de Meckel et la morphogénèse de la mandibule chez l'embryon humain

Résumé A partir d'une série d'embryons humains classés en stades [28], les auteurs étudient l'évolution du cartilage de Meckel dans sa portion ventrale et ses relations avec la morphogénèse de la mandibule. Trois stades apparaissent comme particulièrement importants : Stade 16 : Apparition du cartilage de Meckel ; Stade 20 : Début de l'ossification membraneuse. Stade 23 : Fin de la période embryonnaire (8ème semaine). Le nodule osseux primitif, qui s'est formé aux dépens du mésenchyme embryonnaire, se présente sous l'aspect d'une double lame osseuse formant une gouttière, lit du paquet vasculo-nerveux, dans laquelle vient également s'invaginer la lame dentaire.

     

A role for the basal ganglia in nicotinic modulation of the blink reflex

Summary In humans and rats we found that nicotine transiently modifies the blink reflex. For blinks elicited by stimulation of the supraorbital branch of the trigeminal nerve, nicotine decreased the magnitude of the orbicularis oculi electromyogram (OOemg) and increased the latency of only the long-latency (R2) component. For blinks elicited by electrical stimulation of the cornea, nicotine decreased the magnitude and increased the latency of the single component of OOemg response. Since nicotine modified only one component of the supraorbitally elicited blink reflex, nicotine must act primarily on the central nervous system rather than at the muscle. The effects of nicotine could be caused by direct action on lower brainstem interneurons or indirectly by modulating descending systems impinging on blink interneurons. Since precollicular decerebration eliminated nicotine's effects on the blink reflex, nicotine must act through descending systems. Three lines of evidence suggest that nicotine affects the blink reflex through the basal ganglia by causing dopamine release in the striatum. First, stimulation of the substantia nigra mimicked the effects of nicotine on the blink reflex. Second, haloperidol, a dopamine (D₂) receptor antagonist, blocked the effect of nicotine on the blink reflex. Third, apomorphine, a D₂ receptor agonist, mimicked the effects of nicotine on the blink reflex.     

Expression of transforming growth factor alpha in human tissues: Immunohistochemical study and Northern blot analysis

Summary The expression of transforming growth factor alpha (TGF-) was examined in various human tissues and the fetus, using immunohistochemistry and Northern blot analysis. TGF- immunoreactivity was detected mainly in the epithelial cells of the digestive tract, liver, pancreas, kidney, thyroid, adrenal, skin, mammary gland and genital organs. In the digestive tract, epithelial cells with regenerative change or hyperplastic change showed strong immunoreactivity to TGF-. Peripheral nerve, vessels, megakaryocytes and macrophages in the lung and spleen were also positive for TGF-. By Northern blot analysis the expression of TGF- mRNA was confirmed in the digestive tract, salivary gland, thyroid, kidney and mammary gland. In the human fetus, the nerve tissues, liver, adrenal and kidney were positive for TGF-. Strong immunoreactivity to TGF- was observed in the hepatocytes of the fetus. These findings indicate that TGF- is produced by a variety of nonneoplastic cells in both adult and fetal tissues.     

Hepatitis B surface antigen particles of subtypes adw and adr, and compound subtype (adwr) in symptom-free carriers in Japan.

Of sera from 1,878 Japanese blood donors who carried hepatitis B surface antigen (HBsAg), 420 were subtyped as adw (22.4%) and 1,443 as adr (76.8%); only 15 (0.8%) contained HBsAg of subtype ayw or ayr. Sera with HBsAg/adr had higher HBsAg titres than those with HBsAg/adw (geometric mean of haemagglutination titre: 10.1 +/- 2.4 vs. 9.7 +/- 2.4, p less than 0.01), and a higher prevalence of hepatitis B e antigen (24% vs. 13%, p less than 0.001). Carriers of HBsAg/adr progressively predominated over those of HBsAg/adw with increasing age. Of sera from 1,863 carriers of HBsAg/adw or HBsAg/adr, 182 (9.8%) contained HBsAg particles with both subtypic determinants in the w/r allele. The presence of w and r determinants on the same particles was ascertained by sandwiching them between monoclonal antibody with the specificity for w and that with the specificity for r. HBsAg particles of compound subtype (adwr) were found more often in sera with hepatitis B e antigen than those without it (145/403 [36.0%] vs. 37/1,460 [2.5%], p less than 0.001). Sera with HBsAg/adwr particles had HBsAg titres higher than those without them (12.4 +/- 1.9 vs. 9.7 +/- 2.3, p less than 0.001). HBsAg/adwr particles arise from phenotypic mixing of the S-gene product of wild-type virus and that of mutants with point mutations for subtypic changes. The results obtained indicated that HBV strains of subtype adr have a higher replicative activity than those of adw, and suggested that mutations in the S gene for subtypic changes would be associated with an active replication of hepatitis B virus.     

Development of a quantitative monoclonal antibody‐based immunoassay for humicola ianuginosa on rice grains and comparison with conventional assays

A sensitive, specific, quantitative enzyme‐linked immunosorbent assay (ELISA) has been developed that can be used to determine the extent of mycelial growth of a sporulating thermophilic fungus, Humicola lanuginosa on the surface of rice grains. The assay employs a monoclonal antibody EC6, developed in a previous study, which does not recognize spores of the fungus. Using antigen‐coated wells, a direct linear relationship was established between dilutions of extracts from freeze‐dried mycelium (0.5 to 3 μg/ml) and absorbance values but to eliminate day‐to‐day variations it was found to be necessary to run a dilution series, prepared from stock freeze‐dried mycelium, with every test sample. The ELISA method was compared with conventional quantitative methods. Estimates of total mycelial length in freeze‐dried material by ELISA were found to be in the same order of magnitude as those determined by ergosterol and a theoretical calculation. The ELISA method also compared favourably with direct linear measurements (by photomicrography) of live mycelium present in aliquots from homogenates of a 1 cm² plug taken from a plate but estimates of the latter by the dilution plate count method were much lower. In assays with inoculated rice grains, the quantitative ELISA method proved more sensitive than either the ergosterol method or direct plating of surface‐sterilized grains. The ELISA method also has the advantage of being highly specific and quick to conduct.     

Gestörte alpha2-Adrenozeptorfunktion bei Hämodialysepatienten mit renaler Anämie — eine mögliche Ursache der Blutdrucksteigerung unter rekombinantem humanem Erythropoietin?

Summary Nine patients on maintenance hemodialysis and transfusion-demanding renal anemia (group A) were treated with rHuEPO 120 IU/kg i.v. three times per week. Hemoglobin-content was raised from 7.2±0.9 to 10.4±0.8 g/dl. In all patients blood pressure rose, three patients developed arterial hypertension. Mean diastoloic blood pressure was 66±12 and 78±16 mmHg (p<0.001) before and after rHuEPO. Rise in blood pressure was accompanied by a significant fall in plasma-noradrenaline-levels (from 498±100 to 383±75 pg/ml;p<0.05) and alpha₂-adrenoceptor-density (from 574±76 to 384±49;p<0.05). Compared to nine patients on maintenance hemodialysis and hematocrit over 30% (group B), patients with severe renal anemia (group A before treatment) had higher densities of alpha₂-adrenoceptors (574±76 vs. 218±32;p<0.001) despite higher plasma-noradrenaline-levels (498±100 vs. 399±63; n.s.). We suppose a anemia-related disturbance of alpha₂-receptor-function with the result of abolished receptor down-regulation and impaired vascular reagibility to vasoconstricting stimuli. With the correction of anemia receptor-function improves, receptor down-regulation as well as vascular reagibility is re-established resulting in augmented vascular resistance and higher blood pressure.

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Abkürzungen rHuEPO rekombinantes humanes Erythropoietin - teMAP mittlerer arterieller Blutdruck - RR Blutdrucknach RIVA-ROCCI - RBF regionaler Blutfluß - RPR regionaler peripherer Widerstand     

An Epstein-Barr virus-producer line Akata: Establishment of the cell line and analysis of viral DNA

An Epstein-Barr virus (EBV)-producer line, designated Akata, was established from a Japanese patient with Burkitt's lymphoma. The Akata line possessed the Burkitt's-type chromosome translocation, t(8q-; 14q+), and was derived from the tumor cell. Akata cells produced a large quantity of transforming virus upon treatment of cells with anti-immunoglobulin antibodies (Takada, 1984). Southern blot analysis of viral DNA indicated that the Akata EBV is nondefective and more representative of wild-type viruses. Akata cells should be useful as a source of EBV.     

Desmin as an immunochemical marker of human decidual cells and its expression in menstrual fluid

The expression of intermediate filament proteins in human endometrial tissue was examined. Desmin was selectively expressed in decidualized stroma, as demonstrated by SDS-PAGE analysis and positive response with a monoclonal antibody specific for desmin in ELISA and in western blot analysis. The same monoclonal antibody specifically stained human decidual cells in decidualized endometrium (secretory endometrium) in formalin-fixed paraffin-embedded sections prepared from diagnostic curettage samples. Desmin was also detected in menstrual fluid. Therefore, desmin might serve as a biochemical and histochemical marker of human decidualized endometrium.     

Splenic smooth-muscle tumors in children with acquired immunodeficiency syndrome: report of two cases of this unusual location with evidence of an association with Epstein-Barr virus

Smooth-muscle neoplasms are rarely located in the spleen. They have been previously reported in five cases of children with human immunodeficiency virus (HIV) infection/acquired immunodeficiency syndrome (AIDS). Two cases of children with HIV infection/AIDS with autopsy and surgical pathology evidence of multiple smooth-muscle neoplasms with splenic involvement are presented. DNA was extracted from histology slides in both cases for analysis for Epstein Barr (EB) virus. In both cases, the presence of EB virus was confirmed. This paper documents two additional cases of the unusual phenomenon of splenic involvement by smooth-muscle neoplasms in the setting of AIDS in childhood and further supports the role of EB virus in the development of these neoplasms. Received: 27 January 1999 / Accepted: 23 August 1999     

Detection of cytomegaloviral DNA in human milk cells and cell free milk whey by nested PCR

Human cytomegalovirus (HCMV) DNA can be detected in different compartments of human milk. A protocol for the preparation of milk whey free of fat and cells for the detection of human cytomegalovirus (HCMV) by nested PCR is presented. This is based upon the experience of the separation of more than 200 milk specimens of healthy seropositive breast feeding mothers. HCMV DNA could be detected in freshly centrifuged and filtrated milk whey specimens without contamination by cellular DNA. In limiting dilution experiments using HCMV plasmid DNA, the effect of different DNA extraction procedures from native milk and milk whey on the detection limit of cytomegaloviral DNA was demonstrated. About 200 viral genome equivalents/ml in milk whey or native milk were detectable by classical organic phenol/chloroform extraction or a spin column method, respectively. The detection of viral DNA in milk cells depended on a minimum number of milk cells (10⁵–2×10⁵) available for DNA extraction. In contrast to the findings of cytomegaloviral DNA in native sera or plasma of immunosuppressed patients we failed to amplify low level viral DNA from native breast milk by nested PCR due to an inhibition of Taq polymerase by lipid components. Finally, the course of cell associated and cell free DNAlactia was monitored. Analyzing sequential milk specimens, in some cases the presence of HCMV DNA in colostrum could be demonstrated. DNAlactia of milk cells and whey was partially discordant. Onset (week 1–4 after delivery) and duration (2 weeks up to more than 3 months) of DNAlactia showed distinct individual patterns. The methods described, allow further analysis of the mechanisms involved in the postnatal HCMV transmission by breast feeding seropositive mothers.