Gregor Prindull

Cells in spontaneous DNA synthesis in cord blood of premature and full-term newborn infants: An autoradiographic study

Cord blood from 16 premature infants and 10 full-term infants, and blood from 10 healthy adults, was incubated for 30 minutes with tritiated thymidine, after which an autoradiographic study was made of spontaneously labeling cells. Apart from a varying number of erythroblasts, myelocytes, and an occasional blast cell, two main types of spontaneously labeling cells were observed: transitional cells and large lymphoid cells, previously shown to be phagocytic. Spontaneously labeling cells were 12 times more frequent in cord blood of premature and full-term infants than in the blood of adults. No transitional cells were seen in adult blood.

CFU-F circulating in cord blood

SummaryCFU-F (colony forming units-fibroblast) were studied from cord blood and, as controls, from normal bone marrow of older children and adults. Numbers of CFU-F in cord blood buffy coat cells are lower by a factor of 10 in comparison to bone marrow CFU-F. Cytomorphology and staining with monoclonal antibody identify the progeny cells of CFU-F as fibroblasts. Cord blood CFU-F derived fibroblasts have properties supporting hematopoiesis: They produce CSF (colony stimulating factor) to which fresh cord blood CFU-GM (colony forming units-granulocytic, monocytic) react by colony formation in a dose-response manner. In addition, fibroblast colonies discharge clonogenic round cells into the medium forming CFU-GM and CFU-F colonies in secondary methyl cellulose cultures. We conclude that fetal blood contains clonogenic stromal cells (CFU-F) that give rise to fibroblasts with properties of hematopoietic support.

Leukocyte reserves of newborn infants

Summary and ConclusionsLeukocyte reserves of seven newborn infants have been estimated during therapeutic exchange transfusion, which had effected a leukopheresis. The results will be summarized at the end of the second paper [24], together with data on the restoration of new leukocyte circulating levels after the completion of the exchange transfusion. It then will be possible to conclude whether thetotal leukocyte storage pools had been estimated during ET, or whether additional undetected cell supplies had existed.Zusammenfassung und SchlußfolgerungDurch eine therapeutische Austauschtransfusion wurde bei sieben Neugeborenen eine Leukophorese induziert, die eine Bestimmung der Leukozytenreserven dieser Kinder erlaubt. Die Ergebnisse werden mit den Beobachtungen der Wiederherstellung neuer Leukozytenspiegel nach Beendigung der Austauschtransfusion am Ende der zweiten Arbeit [24] zusammengefaßt. Erst dann wird beurteilt werden können, ob durch die Austauschtransfusion diegesamten Leukozytenvorräte erfaßt werden konnten, oder ob noch weitere Zellreserven vorhanden waren.

Cytoplasmic DNA synthesis by cord blood cells of premature and full-term infants

ZusammenfassungLeukocyten aus Nabelschnurblut von 8 reifen und 12 unreifen Neugeborenen und Blutleukocyten von 10 Erwachsenen wurden mit3H-Thymidin inkubiert. Die anschließende Belichtung der autoradiographischen Filmemulsion erfolgte für 45 und 90 Tage. 1,7% der Lymphoidzellen im Erwachsenenblut, 2,9% und 4,5% der Lymphoidzellen im Nabelschnurblut von Reifgeborenen bzw. Frühgeborenen zeigten eine cytoplasmatische Markierung, die als Ausdruck mitochondraler DNS-Synthese gewertet wurde. Die statistische Auswertung zeigt, daß markierte Zellen im Blut der Frühgeborenen signifikant (p<0,01) häufiger sind als im Blut von Erwachsenen.SummaryCord blood cells from 8 full-term and 12 premature infants as well as blood leukocytes from 10 adults were incubated with3H-thymidine and were subsequently exposed to autoradiographic emulsion for prolonged periods of 45 and 90 days. Cytoplasmic label — which we interpreted as evidence of mitochondrial DNA synthesis — was found in 1.7 per cent of lymphoid cells from adult blood, in 2.9 per cent and 4.5 per cent of lymphoid cells from full-term and premature infants, respectively. Statistical analysis of the data shows that the number of labelled cells is significantly larger in the blood of premature infants than in adults (p<0.01).

Leukocyte reserves of newborn infants: II. Restoration of new leukocyte circulating levels after exchange transfusion

Summary and ConclusionsLeukocyte reserves of 7 newborn infants had previously been calculated during therapeutic exchange transfusion (ET) [10], and the post-ET restoration of new blood circulating levels have been observed in the present study:Reserves of segmented neutrophils about equal in size to the circulating pools before exchange transfusion, were present during the procedure in all infants. The supply was not exhausted in 5 full-term newborns, but the 2 premature infants showed a considerble delay in the restoration of new circulating levels post-ET.Blood lymphocyte reserves were availble during ET in 6 infants. They were exhausted during the procedure or after an additional limited release of cells post-ET. The subsequent increase in the circulating levels was not completed in most cases by 96 hours.Eosinophil reserves during ET were 2 to 3 times larger than the initial circulating pool in all infants. Since post-ET the establishment of a new circulating level was delayed beyond the eosinophil maturation time, the calculated values may represent the total size of the eosinophil reserves of these infants.Monocyte reserves were present in 6 infants. The post-ET restoration of a new circulating level occured in 5 infants within 3 to 6 hours, which is compatible with the short maturation time and the small cell reserves of monocytes in adults.Zusammenfassung und SchlußfolgerungDie Leukozytenspeicher von 7 Neugeborenen waren während einer therapeutischen Austauschtransfusion in der vorausgegangenen Arbeit berechnet worden [10]; die Wiederherstellung neuer Leukozyten-Blutspiegel nach Beendigung des Austausches wurde in der vorliegenden Arbeit gemessen:Während des Austausches waren die Speicher neutrophiler Segmentkerniger bei allen Neugeborenen etwa in Höhe des ursprünglichen Blutspiegels nachweisbar. Nach dem Austausch erwiesen sich die Speicher bei 5 Reifgeborenen als nicht ausgeschöpft; dagegen zeigten die 2 Frühgeborenen eine deutlich verzögerte Wiederherstellung des Neutrophilenblutspiegels.Blutlymphozytenspeicher-bei 6 Probanden während des Austausches nachgewiesen-waren entweder am Ende des Austausches oder nach einer zusätzlichen, begrenzten Ausschüttung von Zellen in den ersten Stunden nach dem Austausch ausgeschöpft. Der Wiederanstieg der Blutlymphozyten war in den meisten Fällen nach 96 Stunden nicht abgeschlossen.Eosinophilenspeicher in doppelter bis dreifacher Höhe des ursprünglichen Blutspiegels bestanden während des Austausches bei allen Neugeborenen. Da ein neuer Eosinophilenblutspiegel nicht vor Ablauf der Eosinophilenausreifungszeit wiederhergestellt wurde, dürfte die Gesamtgröße der Eosinophilenspeicher der Neugeborenen erfaßt worden sein.Monozytenspeicher fanden sich bei 6 Kindern. Die Wiederherstellung eines neuen Blutspiegels im Anschluß an die Austauschtransfusion bei 5 Neugeborenen innerhalb von 3 bis 6 Stunden stimmt mit der kurzen Ausreifungszeit und den kleinen Speichern der Monozyten bei Erwachsenen überein.

Minimal residual disease in vitro of a pre-B-lymphoma

We have studied the survival of clonogenic neoplastic cells of a murine pre-B-lymphoma (BCl-1) of the spleen in culture. We have found quantitative deficiencies such as reduced surface adherence of stromal cells and impaired CFU-F (colony forming units-fibroblast) and pre-CFU-F colony and layer formation in stromal cultures of lymphoma bearing spleen, as compared to cultures from normal spleen. There are two populations of clonogenic BCl-1 lymphoma cells surviving in culture: one population is surface adherent, and the other is non-adherent. Both populations transmit the lymphoma to healthy indicator mice. We hope that this model will be helpful in studying minimal residual leukemic disease [1] in culture.

Successive stimulation of major cell groups in bone marrow

The existence of pluripotential haemopoietic stem cells raises the possibility of stem cell competition when two or more differentiating stimuli are given either simultaneously or in close succession. The experiments now reported deal with the effects on guinea pig bone marrow of successive stimulation and they fall into two groups. In one group, erythropoiesis was first stimulated by means of hypoxia, after which granulopoiesis was stimulated by the intraperitoneal injection of typhoid vaccine. In another group, these two stimuli were given in the reverse order. Bone marrow changes were evaluated both quantitatively and by differential counts. The experimental animals were compared with controls given only one stimulus, either hypoxia or vaccine, and also with normal untreated animals. As judged by the output of granulocytes or erythrocytes, no stem cell shortage developed in the experimental animals. A marked fall in transitional cells in the bone marrow of the experimental animals is consistent with the view, though not affording actual proof, that the pluripotential stem cells are to be found in the transitional cell compartment.