Parental mosaicism and autosomal dominant mutations causing structural abnormalities of collagen I are frequent in families with osteogenesis imperfecta type III/IV

Abstract Protein-chemical and molecular studies were conducted on all osteogenesis imperfecta (OI) type III/IV patients referred to our hospital during the last 15 y. Of a total of 16 OI type III/IV patients studied, 15 patients were heterozygous for a mutation in one of the two genes coding for collagen I, COL1A1 or COL1A2. Cultured fibroblasts from these 15 patients produced both normal and abnormal collagen I molecules, pointing to a dominant-negative effect of the mutation. Nine mutations had not been described previously. Parental mosaicism was demonstrated in three families. In the 16th child the causative mutation was not found. In conclusion, OI type III/IV in most patients of Western European ancestry is caused by dominant mutations in the genes for collagen I, and recurrence of OI is caused in most cases by parental gonadal mosaicism.     

Neonatal hearing screening with an automated auditory brainstem response screener in the infant's home

Universal neonatal hearing screening is essential if all infants with congenital or perinatally acquired hearing impairment are to begin treatment before the age of 6 months to facilitate development of speech, language, communication and academic skills. Screening cannot always take place in hospital because of the increase in very short-stay deliveries. Therefore screening in the home may be necessary to achieve a high level of screening. We describe a feasibility study with an automated auditory brainstem response (AABR) screener in the infant's home as part of the service offered by the Well Baby Clinics in the Netherlands. Of the 277 infants who completed the screening 266 had the result "pass", 7 "refer" and 4 had inconclusive results. The mean time needed per screening was 18 min. This study shows that neonatal hearing screening by nurses using an AABR infant screener in the home is feasible.     

Prospective evaluation of posttransfusion hepatitis

The incidence of posttransfusion hepatitis (PTH) was determined prospectively at our institution. An active surveillance program of transfused surgical patients was set up; alanine aminotransferase (ALT) levels were determined before transfusion and at monthly intervals for 6 months after transfusion. Patients with confirmed ALT values greater than 2.5 times the upper reference values were referred to the out-patient clinics for diagnosis. Of 4051 surgical patients who underwent transfusion between January 1986 and December 1989, 2459 (60.7%) were enrolled in the surveillance program, and 1018 (25.1%) completed the follow-up; 238 patients received autologous blood only and were used as controls. No PTH was observed in the control patients, and the incidence of the disease in patients receiving homologous blood was 10.97 percent in 1986, 6.58 percent in 1987, 5.55 percent in 1988, and 4.29 percent in 1989; the decreasing trend is significant (p = 0.018).     

Pediatric peripheral blood progenitor cell collection: haemonetics MCS 3P versus COBE Spectra versus Fresenius AS104

BACKGROUND: An increasing number of apheresis machines are becoming available for peripheral blood progenitor cell (PBPC) collection in children. STUDY DESIGN AND METHODS: At the Children's Hospital of Florence (Italy), three apheresis machines were evaluated: MCS 3P (Haemonetics) (10 procedures in 4 patients, aged 10–12 years, weight 23.5-64 kg), Spectra, (COBE) (8 procedures in 3 patients, aged 4–17 years, weight 19–59 kg), and AS104 (Fresenius) (24 procedures in 9 patients, aged 2–16 years, weight 13.6-60 kg). For PBPC quantitative analysis, CD34 cytofluorimetry was employed. Relevant variables analyzed included efficiency of CD34+ cell extraction and enrichment, mononuclear cell purity and red cell contamination of the apheresis components, and platelet count decreases after leukapheresis. RESULTS: No significant differences in CD34+ cell-extraction abilities were found. However, the AS104 provided consistently purer leukapheresis components in terms of mononuclear cell and CD34+ cell enrichment (441 +/− 59%, vs. 240 +/− 35% and 290 +/− 42% for MCS 3P and Spectra, respectively). Postapheresis platelet counts dropped the least with the AS104. The smallest patient who underwent apheresis with MCS 3P (the only machine working on discontinuous flow and hence with greater volume shifts) weighed 23.5 kg and tolerated the procedure well, with no signs of hemodynamic instability. No significant complications were observed. CONCLUSION: All machines seem to have comparable PBPC extraction efficiency, but the AS104 seems to give the component with the greatest PBPC enrichment. This feature might be relevant for further ex vivo cell processing (CD34+ cell selection, expansion, and so on).     

Amantadine potentiates T lymphocyte killing by an anti-pan-T cell (CD5) ricin A-chain immunotoxin

The studies described in this report demonstrate that 1-adamantanamine hydrochloride (amantadine) is a potent enhancer of the cytotoxic activity of the anti-pan-T lymphocyte (CD5) T101 monoclonal antibody conjugated to purified ricin A-chain (T101-immunotoxin; T101-IT). We also demonstrate that T101-IT in the presence of amantadine does not induce immunotoxin-mediated cytotoxicity in nontarget cells such as human marrow hematopoietic progenitor cells. These results provide further knowledge for the improvement of ex vivo purification of human bone marrow from normal or leukemic T cells prior to allogeneic or autologous stem cell transplantation, respectively. Furthermore, since amantadine has long been employed safely in human therapy, its use in conjunction with immunotoxins might be exploited in vivo.     

Uncoordinated expression of fibrinogen compared with thrombospondin and von Willebrand factor in maturing human megakaryocytes

The localization of three known alpha-granule proteins, thrombospondin (TSP), von Willebrand factor (vWF), and fibrinogen (Fg) has been studied in human megakaryocytes (MK) by immunofluorescence and immunoelectron microscopy. For this study, highly purified populations of MK were prepared from human bone marrow either by counterflow centrifugal elutriation or by cell culture from normal subjects and from two patients with megakaryoblastic leukemia. In normal bone marrow immature MK, TSP, and vWF were observed in the Golgi-associated vesicles and in small immature alpha-granules; in mature MK, they were found in the matrix of the mature large alpha-granules. Surprisingly, Fg was detected neither in the Golgi area, nor in the small precursors of alpha-granules; it was only found in the mature alpha-granules but this labeling was generally weaker than in blood platelets. In order to confirm these differences between the expression of Fg and vWF or TSP additional studies were performed on cultured maturing MK: immunofluorescent and ultrastructural immunogold labeling confirmed that vWF appeared early in the maturation while the same immature MK were negative for Fg. In the late maturation stage, the three proteins were detected in the alpha-granules. In order to know whether Fg was lately synthesized or endocytosed from the outside medium, normal MK were grown in the presence of either normal or afibrinogenemic plasma, and normal serum. Fg was detected only in the alpha-granules of MK grown in normal plasma. Similar results were observed with malignant MK, whose maturation was independent of the culture conditions. In conclusion, this study brings immunocytochemical evidence that vWF and TSP are synthesized by immature MK, whereas Fg appears later in the MK alpha-granules and its expression is dependent of the presence of an exogenous Fg source.     

Biochemical properties of the eosinophil cationic protein and demonstration of its biosynthesis in vitro in marrow cells from patients with an eosinophilia

The eosinophil cationic protein (ECP), which has been shown to be secreted both in vitro and in vivo, is a cytotoxic unique constituent of eosinophil granules. To increase the understanding of the mechanisms behind the role of the eosinophil as a cytotoxic effector in disease, a detailed biochemical characterization of ECP was performed. A considerable molecular heterogeneity was revealed when purified ECP was eluted isocratically from a high-resolution cation exchange resin; the separation, reproducibly achieved, of five components was probably due to hydrophobic interaction with the resin. These polypeptides, which reacted quantitatively with anti-ECP antiserum, showed molecular weights (mol wt) of 19,500 and 16,700 and showed almost identical amino acid compositions. The amino-terminal sequence for one of the polypeptides was (in the standard one-letter code) (R-P-X-Q-F-T-R-A-Q-W- F-A-I-Q-H-I-S-L-N-P-R-R-C-T-I-A-M-R-A-I-N-N-Y-). The biosynthesis of ECP was demonstrated in marrow cells from patients with eosinophilia using labeling with (14C)-leucine, followed by immunoprecipitation with anti-ECP, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and fluorography for visualization of labeled ECP. Biosynthesis was demonstrated of mol wt 22,000 ECP, which may represent precursor ECP, since with time some of it was processed into ECP with a mol wt of 18,000 to 19,000. Monensin, a proton ionophore, blocked the processing of mol wt 22,000 ECP. This study shows that ECP consists of a family of similar polypeptides. These may, however, have different biological activities.