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Biomedical subjects

R Moog

Publications and source records attributed to R Moog.

At least 37 records · Page 2Linked to original sources

Evaluation of a concurrent multicomponent collection system for the collection and storage of WBC-reduced RBC apheresis concentrates.

BACKGROUND: Multicomponent apheresis procedures offer the possibility of collecting blood components that are standardized, as compared to those available with whole-blood donations. A new separator program for the concurrent collection of RBCs, platelets, and plasma (Amicus, Baxter Healthcare) was evaluated. STUDY DESIGN AND METHODS: Apheresis donors (n = 47) underwent concurrent collection of RBCs, platelets, and plasma by use of the single-needle procedure of the Amicus blood cell separator. A standardized RBC volume (100% Hct) of 200 mL was targeted with either 1 or 2 platelet concentrate units, depending on the donor's predonation characteristics. After collection, the RBC component was sterilely connected to an RBC collection set (Amicus) to allow for the addition of 100 mL of saline-adenine-glucose-mannitol preservative solution and WBC reduction at either ambient temperature or 4 degrees C. The RBC units were subsequently stored at 2 to 6 degrees C for 42 days, and the following in vitro measures were evaluated over the storage period: blood cell counts including Hct and total Hb, plasma Hb, potassium, pH, ATP, and 2,3 DPG. RESULTS: Procedure time averaged 74 +/- 9 minutes, and no adverse events were reported. The absolute RBC volume collected averaged 198 +/- 11 mL with an average Hct value of 83 +/- 2 percent. After filtration, the Hb content averaged 58.2 +/- 2.4 g per unit and residual WBCs averaged 0.038 +/- 0.015 x 10(6) per unit. Day 42 results showed that all units had on average more than 70-percent ATP maintenance, and all of the units had less than 0.8 percent he-molysis. All units had pH values higher than 6.5 on Day 42. CONCLUSION: The concurrent multicomponent collection system (Amicus) can reliably collect a standardized RBC unit of good quality. In vitro testing of the RBCs collected and stored for 42 days met the Council of Europe criteria for transfusion.

Adenosine Triphosphate↗

Three-flap anoplasty for imperforate anus: results for primary procedure or for redoes.

UNLABELLED: Three-flap anoplasty was first described in 1987 by Yazbeck for the treatment of rectal prolapse after pull-through operations for imperforate anus, and in 1992 in a case of anterior perineal approach. It is intended to reproduce the normal anatomy of a sensitive anal canal. The purpose of this study is to evaluate 14 children (9 boys and 5 girls) operated for imperforate anus. METHOD: Eleven children had an intermediate or high imperforate anus and 3 had a low imperforate anus. Nine were operated for the first time with a three-flap anoplasty (GrA), and 5 were reoperated with this technique because of fecal incontinence and/or rectal prolapse (GrB). Seven patients had associated malformations: one Hirschsprung's disease, one cloacal defect with renal insufficiency, three complex caudal malformations with tethered cord, one Down syndrome, and two psychological and psychomotor troubles. The patients (average age = 6 years) have been evaluated every year since 1997, with a questionnaire based on a clinical score validated with 30 healthy children, used as a control group. Ten anal manometries were carried out. RESULTS: In 1998, the GrA score was 16.1 (control = 22.5) and the GrB score was 11.5 (p = 0.25). In 1999, GrA and GrB score were approximately the same. The score of those without associated anomalies was 19.6 whereas the score of the children with other malformations or anomalies was 10 (p = 0.02). Anal manometry is almost normal in patients with low or intermediate imperforate anus (rectoanal relaxation reflex for 10 cm H2O, and basal resting pressure more than 40 cm H2O). Even though anal manometry is subnormal in patients with Down syndrome or psychomotor troubles, the clinical score remains low (score = 10). In cases of complex caudal malformations or high imperforate anus, the results of anal manometry and clinical score are bad (score 9.7). CONCLUSION: The three-flap anoplasty can be carried out in newborns without colostomy and often represents the only possible surgical approach to avoid a laparotomy. This plasty, proposed secondarily to correct a defect of continence, can be performed without colostomy, with satisfactory results.

Anus, Imperforate↗

Adverse events in peripheral progenitor cell collection: a 7-year experience.

Collection of peripheral progenitor cells (PPC) by apheresis machines is generally regarded as a safe procedure. However, data about adverse events in PPC harvesting are scarce. In a monocentric retrospective study, the data of 540 PPC collections in a period of 7 years were reviewed. Adverse events were subdivided in collection-associated technical problems and patient/donor-related side effects. Patient/donor-related side effects occurred most often (19.8%); most of them were paresthesias due to citrate toxicity. Paresthesias were treated by oral (20.4%) or intravenous (1.1%) calcium supplementation. Problems with venous access were also seen frequently, resulting in blood flow alarms (11.3%) and blockades in the return line (4.3%). A total of 6.9% of these problems were catheter associated, requiring revision of the central venous line in 2.6%. Technical problems with the blood cell separators were observed in 11.7%. Ten PPC collections were discontinued due to adverse events. The data of this retrospective, monocentric analysis show that patient/donor-associated problems were observed in every fifth PPC harvest. Most of them were paresthesias, which could be easily treated by calcium supplementation. Problems with venous access and technical problems with the cell separators occurred in every tenth PPC collection.

Adolescent↗

Effect of nucleoside analogues and oligonucleotides on hydrolysis of liposomal phospholipids.

The hydrolysis of the bilayer forming phospholipids resulting first of all in lysophospholipids and fatty acids is one limiting factor determining the shelf-life of liposomes. In several studies the influence of pH, buffer, lipid composition and other parameters on the hydrolysis of phospholipids have been demonstrated, but the influence of drugs has not yet been investigated systematically. In this study the influence of nucleoside analogues, especially 2', 2'-difluoro 2'-deoxycytidine (gemcitabine, dFdC) on the degradation of phospholipids was elucidated in more detail. It could be demonstrated that the interaction of dFdC with phospholipid bilayers promotes the hydrolysis of phospholipids in a concentration-dependent manner. Obviously two parts of the molecule, the amino group bound to the pyrimidine moiety and the 2', 2'-difluoro-2'-deoxyribose, seem to be responsible for the forced phospholipid hydrolysis. The dFdC-induced hydrolysis of phospholipids was influenced by pH, buffer, lipid composition and different anions. Optimization of the above parameters resulted in prolonged shelf-life of dFdC liposome dispersions, which is an important prerequisite for clinical practice.

Anions↗

Periodic alternating interface positioning to lower WBC contamination of apheresis platelet concentrates: a multicenter evaluation.

BACKGROUND: A new software version of a cell separator (AS TEC 204, Fresenius) providing WBC-reduced single-donor plateletpheresis concentrates was tested. STUDY DESIGN AND METHODS: Dual-needle apheresis procedures (n = 621) were performed in three centers, using either fixed interface positioning (FIP) or periodic alternating interface positioning (PAIP). The other separation parameters (e.g., anticoagulant:whole-blood ratio, and blood flow) were set individually. All platelet concentrates were evaluated for platelet yields and contaminating WBCs. RESULTS: The introduction of the PAIP resulted in a significant (p<0.001) reduction in contaminating WBCs (median, 30,000) from the numbers seen with FIP (median, 2,300,000) while maintaining the separation efficacy (47%) and separation time. Ninety-eight percent of all concentrates contained less than 5 x 10(6) WBCs per concentrate and 92 percent contained less than 1 x 10(6). CONCLUSION: Plateletpheresis using the AS TEC 204 cell separator with PAIP is a valid alternative to WBC reduction by filtration. It may provide WBC-reduced platelet concentrates without the additional cost of filters. However, the reliability of the WBC reduction is not yet advanced enough that PAIP can be employed without any monitoring of the end product.

Blood Platelets↗

Radiological evaluation of Duhamel's operation in Hirschsprung's disease. Attempt at radio-clinical correlation.

The aim of this study was to evaluate the results of the Duhamel cure technique in a case of Hirschsprung's disease with a barium colorectal opacification by low approach. The overall height of the rectal stump (HR), the depth of the blind part of the rectum (PR), the rectal diameter (DR), the diameter of the colorectal anastomosis (DA) were measured. The rectal volume of its blind part (VRB), the rectal volume of its functional part (VRF), the surface of the colorectal and subanal anastomosis, the VRF/VRB ratio were calculated. Two types of subgroups were analysed: -the patients in whom the rectal stump had been closed by stapling (13 cases) and those where the rectal stump was manually closed (13 cases). -the patients who had no transit trouble (20 cases) and those in whom a stercoroma or coproma had formed, including phenomena either similar to encopresia or to soiling. The manual suture of the top of the rectal stump does not show any significant difference compared to stapling. The rectal height (HR=71 mm+/-1.9), the blind rectal stump depth (PR = 36 mm+/-2.2) of the 6 patients with stercoroma are significantly higher than with the other 20 patients (HR = 51.6+/-2.6 and PR = 24.4+/-2.7, i.e. respectively p = 0.0005 and p = 0.03). VRF and VRB are equal in the group with stercoroma, and VRF is twice or more than VRB in the group without any problem. If it is impossible to obtain a sufficiently short rectal pouch, an excessive HR may be balanced by a longer colorectal anastomosis with a higher VRF/VRB ratio. This is of importance in laparoscopic procedure.

Barium Sulfate↗

Cost effectiveness of quality assurance in plateletpheresis.

BACKGROUND AND OBJECTIVES: A quality assurance system (QAS) is part of modern blood banking facilities. Quality control of single donor platelet (SDP) concentrates includes the determination of the platelet (PLT) yield and the white blood cell (WBC) contamination. Improvements in modern apheresis technology allow the collection of high PLT yields and leukoreduced products. Double dose SDPs can be split and WBC-reduced products may be labelled as leukodepleted thereby reducing costs. MATERIAL AND METHODS: 3309 SDPs obtained with the Amicus, AS 104, AS.TEC 204 and MCS + blood cell separators were retrospectively analysed for their PLT yield. SDPs with > or = 4.0 x 10(11) PLTs were considered as double dose SDPs and split. WBCs were determined microscopically in 170 SDPs. SDPs with a leukocyte content < 1.0 x 10(6) were labelled as leukodepleted and no further WBC filtration was recommended. RESULTS: PLT yield was statistically higher in SDPs from the Amicus device, 84.8% of these products could be split. Double dose concentrates were collected in 22.7% with the MCS + machine and in 4.8% with the AS 104/AS.TEC 204 blood cell separators. The savings for disposables was $150,041 and for infectious disease testing $75,766. After the subtraction of the costs for PLT determinations in all SDPs $215,880 could be saved. WBC contamination was statistically lowest in in-line filtered SDPs from the MCS + device (median 0.29 x 10(5), range 0.22-9.96 x 10(5)) and all of these products were considered as fulfilling the criterion of leukodepeletion so that we were able to save $17,135 for bedside filters. Median WBC content was 0.75 x 10(5) (range 0.35-22.5 x 10(5)) in SDPs from the Amicus and 0.9 x 10(5) (range 0.27-99.8 x 10(5)) in SDPs from the AS 104/AS.TEC 204 devices, respectively. CONCLUSION: Blood cell separators of the newest generation allow the collection of leukodepleted double dose SDPs. An intensified QAS in plateletpheresis allows the decision whether a product can be split and/or released as leukodepleted. By this means we were able to save a total of $233,015 per year.

Cost-Benefit Analysis↗

White cell reduction during plateletpheresis: a comparison of three blood cell separators.

BACKGROUND: White cell (WBC)-reduced single-donor platelet concentrates (SDPs) can be collected by the newest generation of blood cell separators. Three WBC-reduction techniques during plateletpheresis were investigated in the present study with respect to WBC content and platelet yield. STUDY DESIGN AND METHODS: The Amicus device used the elutriation principle for WBC reduction, and separations with periodically alternating interface position (PAIP) were employed in the AS.TEC 204. WBC reduction by in-line filtration was performed in the MCS+. Platelets were measured electronically and WBCs were determined manually (Nageotte chamber). RESULTS: In-line filtered SDPs showed significantly lower WBC content (0.088+/-0.178 x 10(6)) than SDPs that were WBC reduced by elutriation (0.31+/-0.48 x 106) or PAIP technique (0.89+/-1.57 x 10(6), p = 0.0001). Platelet yield (5.0+/-0.46 x 10(11)) was significantly higher in components obtained with the Amicus device (p = 0.0001). The AS.TEC 204 and MCS+ gave similar results for platelet yields: 3.15+/-0.63 and 3.28+/-0.71 x 10(11), respectively. CONCLUSIONS: The plateletpheresis systems studied allow the collection of WBC-reduced SDPs. In-line filtration resulted in the best WBC reduction. Some SDPs collected with the devices studied had a WBC content >1 x 10(6) per unit. Platelet yield was significantly higher in SDPs from the Amicus device.

Blood Cells↗

Harvesting of peripheral blood progenitor cells with different programmes of discontinuous flow systems.

BACKGROUND AND OBJECTIVES: From a technical point of view two problems arise during the collection of peripheral blood progenitor cells (PBPC): first, the volume of the apheresis product is often large, requiring volume reduction prior to cryopreservation. Second, the platelet (PLT) loss due to the harvesting of the buffy coat is an unwanted side effect. With respect to these problems, the present study was designed to compare programs for PBPC collection with discontinous-flow cell separators. MATERIALS AND METHODS: Three different protocols for PBPC harvesting were investigated in 32 patients with malignancies. In the first protocol, the blood cell separator Haemonetics MCS 3p was used. In the second protocol using the same machine, the opening and closure of the stem cell valve was modified in combination with a centri surge to reduce the PLT loss. The MCS+ device with another configuration of the valves was used in the third protocol. PBPC were mobilised by chemotherapy plus cytokine administration or application of growth factor alone. Blood counts and CD34 antigen-expressing cells were determined before apheresis and in the PBPC product. Colony-forming unit granulocyte/macrophage (CFU-GM) were determined in the apheresis product. RESULTS: 55 PBPC collections were carried out with a median end product volume of 105 ml. The median counts for CD34+ antigen-expressing cells and CFU-GM were 1.5x10(6 )and 2.5x10(4)/kg body weight, respectively. PLT loss was significantly lower in protocol III. CONCLUSION: The study reported here revealed that PBPC could be easily collected in a reduced product volume by the intermittent-flow cell separators. No additional centrifugation prior to cryopreservation was necessary to remove the plasma from the apheresis product. Patient's PLT loss was reduced by the centri surge technique but this still has to be improved.

Anticoagulants↗

Technical aspects and performance in collecting peripheral blood progenitor cells.

The combination of effective mobilization protocols and efficient use of apheresis systems has led to a rapid growth of peripheral blood progenitor cell (PBPC) transplantation. The specifications for these procedures are changing towards more automated systems for standard collections to minimize operator interaction and to collect PBPC efficiently from donors and patients and also to reduce the collection of undesired cells such as polymorphonuclear cells and platelets using functionally closed, sterile environments for collection, in keeping with good manufacturing practice guidelines. The increasing need for pediatric procedures requires apheresis systems that run efficiently at low flow rates. It is also desirable to have a low extracorporeal volume. Technical considerations related to PBPC harvesting should include strategies facilitating more efficient collection such as large-volume leukapheresis, which is able to increase the PBPC yield. The most common complication related to apheresis is catheter occlusion, and care should be taken to prevent thrombosis and maintain vascular access. However, refinement and improvement of collection techniques continue to add to the armamentarium of current approaches for cancer and nonmalignant conditions and will enable the development of new strategies.

Blood Component Removal↗

Platelet collection with the Amicus and the AS.TEC 204 blood cell separators.

BACKGROUND: Platelet collection with two new blood cell separators was compared with respect to platelet yield, separation efficiency, white cell (WBC) contamination, and measures of component quality. Both machines offer a menu for the collection of a desired platelet yield. The harvesting of a definite platelet yield is a means of collecting a standardized therapeutic platelet dose. STUDY DESIGN AND METHODS: One hundred seventy-two platelet collections were carried out with different protocols in the two devices (Amicus and AS.TEC 204). For that reason, healthy donors underwent plateletpheresis procedures using the continuous- and discontinuous-flow systems. Separations with a definite endpoint volume and the option of collecting a desired platelet yield of 5.5 x 10(11) in the Amicus and 3.3 x 10(11) in the AS.TEC 204 machine were investigated. RESULTS: With the Amicus blood cell separator, platelet yield (5.02+/-0.46 x 10[11]) and separation efficiency (66.9+/-6.2%) were significantly higher than those with the AS.TEC 204 (3.02+/-0.62 x 10[11] and 46.4+/-6.7%, respectively). There was less deviation between the platelet yield and the desired platelet yield in the AS.TEC 204 machine than in the Amicus device. WBC contamination was 2.06+/-2.91 x 10(6) in components obtained from the AS.TEC 204 machine, and 87.5 percent of the platelet concentrates had a WBC content <5 x 10(6). None of the components from the Amicus device contained more than 5 x 10(6) WBCs. Except for platelet morphology score, measures of component quality were almost equal in the platelet concentrates obtained from the studied machines. CONCLUSION: Platelet yield and separation efficiency were significantly higher in the Amicus blood cell separator. The collection of a desired platelet yield was better achieved with the AS.TEC 204 device.

Blood Component Removal↗

Circadian reactions to nCPAP treatment.

To determine possible effects of apnea attacks on the spontaneous behavior of the circadian system (body temperature, sleeping behavior, vigilance), 11 patients with obstructive sleep apnea (OSA) were observed before therapy over a 24 h period under a special constant routine (bed-rest study) and again during therapy with nCPAP (nasal continuous positive airway pressure). Clinical indicators (polysomnographical, subjective sleep quality, etc.) indicated successful therapy. During the bed-rest study with nCPAP therapy, the 24 h amplitude of core temperature was found to be greater than the amplitude measured before therapy. Also, therapy decreased sleep disturbances at night and reduced daytime sleeping times. Consequently, the level of subjective vigilance was higher during the daytime during therapy. OSA attacks do not only impair sleep; they disturb the whole circadian system. This may also impair recuperation and sleep. Further research should test whether measurements of the spontaneous circadian system could have additional diagnostic value and whether the stabilization of the circadian system has therapeutic value.

Adult↗

[Hepatic trauma: pediatric features].

Conservative management of hepatic trauma has been demonstrated to be effective in children. However, surveillance of these patients in a specialized paediatric surgery unit is essential because of the possibility of rare, but unavoidable complications. The authors review the 20-year experience of conservative management of hepatic trauma reported in the literature.

Blood Transfusion↗

Collection of platelets and peripheral progenitor cells with the fresenius AS.TEC 204 blood cell separator.

The aim of the present study was to clinically evaluate the blood cell separator AS.TEC 204. One hundred fifteen platelet collections were carried out with the dual or single needle procedure. Platelet yield was 3.21 +/- 0.80 x 10(11) (mean +/- standard deviation) and 59.1% of the collections showed platelet counts > or = 3.0 x 10(11). Leukocyte contamination was 1.77 +/- 2.81 x 10(6) and 89.0% of the platelet concentrates had a white blood cell content < 5 x 10(6). Using a dual needle technique with an alternating interface adjustment, all of the products were contaminated with less than 1 x 10(6) leukocytes. Furthermore, 23 peripheral progenitor cell collections were performed in 12 patients and three allogeneic donors. Median numbers of harvested CD 34 antigen expressing cells/kg body weight were 0.78 (range 0-4.7) and 3.67 x 10(6) (range 2.2-5.23), respectively. We conclude that platelet and progenitor cell collections can be carried out with efficient results. The collections were well tolerated by the donors.

Adult↗