Splitting CO2 with a ceria-based redox cycle in a solar-driven thermogravimetric analyzer.

Thermochemical splitting of CO2 via a ceria-based redox cycle was performed in a solar-driven thermogravimetric analyzer. Overall reaction rates, including heat and mass transport, were determined under concentrated irradiation mimicking realistic operation of solar reactors. Reticulated porous ceramic (RPC) structures and fibers made of undoped and Zr4+-doped CeO2, were endothermally reduced under radiative fluxes of 1280 suns in the temperature range 1200-1950 K and subsequently re-oxidized with CO2 at 950-1400 K. Rapid and uniform heating was observed for 8 ppi ceria RPC with mm-sized porosity due to its low optical thickness and volumetric radiative absorption, while ceria fibers with µm-sized porosity performed poorly due to its opacity to incident irradiation. The 10 ppi RPC exhibited higher fuel yield because of its higher sample density. Zr4+-doped ceria showed increasing reduction extents with dopant concentration but decreasing specific CO yield due to unfavorable oxidation thermodynamics and slower kinetics.

Promising results after the treatment of simple and complex distal humerus type C fractures by angular-stable double-plate osteosynthesis.

INTRODUCTION: The aim of this study was to evaluate the functional results and complications following open reduction and internal fixation of distal humerus type C fractures (AO classification) using an anatomically precontoured, angular-stable double-plate system. PATIENTS AND METHODS: The study is a retrospective analysis of 45 patients with 46 type C fractures. There was one C1, eight C2 and 31 C3 fractures. Twelve fractures were open (Gustilo classification). Follow-up was performed on 38 patients with 39 fractures (84%) after 14 months (range, 12-22). The mean age was 50 years (range, 14-87). Functional results were evaluated using the Mayo Elbow Performance Score (MEPS); the Disabilities of the Arm, Shoulder and Hand score (DASH); and range-of motion (ROM) measurements. Complications were classified as minor or major, and the postoperative and follow-up X-rays were analyzed. RESULTS: Thirty-four fractures were considered stable to allow early physical therapy. With a mean MEPS of 85 points, 36 results (36/39 [92%]) were rated as excellent or good. The mean DASH was 22.5 points, and the ROM for extension-flexion was 105° (range, 50-145). Sixteen major complications (eventually coexistent: 6 × implant failure, 3 × non-union, 6 × stiffness, 2 × necrosis capitulum, 4 × failure olecranon osteotomy refixation) and two minor complications were recorded in 17 patients. These adverse events led to 14 revision surgeries (14/39 [36%]). Except for extension deficit, no statistically significant differences were found between the articular simple and articular complex fractures and when comparing the results between patients with and without a major complication. CONCLUSION: The anatomically precontoured and angular-stable double-plate system provides sufficient immediate postoperative stability to allow early physiotherapy, even in C3-type fractures. Excellent or good results could be achieved in the vast majority of patients, independent on having suffered a complication or not. Complication rates were remarkably high, emphasizing the difficulties associated with this rare type of fracture. LEVEL OF EVIDENCE: Level IV Retrospective study.

[Phylogeography of pacific herring Clupea pallasii from Eurasian seas].

Eleven samples of Pacific herring from the four seas of Eurasia (Sea of Japan, Sea of Okhotsk, Bering Sea, and White Sea), and one sample of Atlantic herring were analyzed. Complete and partial sequences of the mtDNA control region with the sizes up to 1071 bp were used. To verify the haplogroups identified, additional sequencing of the cytochrome oxidase I gene was performed. It was demonstrated that Pacific herring from the seas of Eurasia belonged to one mitochondrial haplogroup. The gene flow between the localities from different parts of the Far Eastern sea basins was about 11% per locality, per generation, which led to constant leveling of herring intraspecific differentiation. The data presented gave no reasons for subdivision of the herring populations in accordance to ecological characters (lacustrine and marine). Analysis of global molecular variance (global AMOVA) demonstrated that in Asian water basins, more than 98% of molecular polymorphism was found within the samples at the low level of significance (p < 0.05).

One-third tubular-hook-plate osteosynthesis for olecranon osteotomies in distal humerus type-C fractures: a preliminary report of results and complications.

INTRODUCTION: Distal humerus fractures are rare and challenging to treat. Anatomic reduction of the articular surface and stable osteosynthesis are mandatory for satisfactory results. The transolecranon approach allows superior visualisation of the joint. However, controversy exists regarding how best to fix the osteotomy. The purpose of the present study was to investigate the eligibility of a one-third tubular hook plate for osteosynthesis of olecranon osteotomies in distal humerus type-C fractures. PATIENTS AND METHODS: A consecutive series of 34 patients who were treated through an olecranon osteotomy and underwent fixation using a one-third tubular hook plate were identified. Thirty-one patients (17 females, 14 males) with a median age of 50 years (14-87, standard deviation (SD) 18.3) were available for a comprehensive assessment after a mean of 12.3 months (6-20, SD 3.7). Using the Arbeitsgemeinschaft für Osteosynthesefragen (AO) classification, six (19.4%) fractures were categorised as type C2 and 25 (80.6%) were categorised as C3. Physical and radiological examinations were performed. The Mayo Elbow Performance Score (MEPS) and the Disabilities of the Arm, Shoulder and Hand score (DASH) were evaluated. RESULTS: Mean extension-flexion ROM was found to be 102° (50-145°, SD 25). Pronation and supination were only slightly compromised. The mean MEPS was 87.2 points (50-100, SD 12.4). Fourteen patients (45.2%) were rated as excellent, and 15 (48.4%) were rated as good. One patient was rated fair, and one patient was rated as poor, respectively. Mean DASH score was 24.4 points (0-65, SD 20.3). Complications regarding the osteotomy occurred in seven patients (22.5%). Revision surgery was necessary in five cases (16%). At follow-up, all osteotomies went on to union. Mild joint degeneration (Broberg I) was found in 10 patients (32.2%). Implant removal was carried out in 15 patients (48.4%). CONCLUSION: Based on this study, the osteosynthesis of olecranon osteotomies using a one-third tubular hook plate can be regarded as a safe procedure with a low complication rate. The implant needed is widely available and cost-efficient, in contrast to specially designed plates or nails.

[Total elbow arthroplasty as a treatment option in complex injuries of the elbow in elderly patients]. / Die Ellenbogentotalendoprothese in der Versorgung schwerer Ellenbogenverletzungen des älteren Patienten.

AIM: The aim of this study was to evaluate the functional outcome of patients with severe elbow injuries treated by primary and secondary implantation of an elbow prosthesis using two different functional scores. METHOD: To determine whether or not total elbow replacement is an acceptable treatment option in such cases, we analysed the functional outcome of patients after primary or secondary implantation of the semi-constrained Coonrad-Morrey prosthesis. Between March 2005 and September 2009 we implanted 25 Coonrad-Morrey prostheses in 24 patients with acute or chronic elbow injuries. Eight patients had complex type C3 fractures according to the AO classification and were treated with primary implantation. 16 patients received a secondary implantation including 3 chronic luxations, 3 non-unions of the bone, 3 failed osteosyntheses, 7 patients with post-traumatic arthrosis and 1 reimplantation. The mean follow-up after the operation was 12 (± 8) months. The functional outcome was measured by assembling the "Mayo elbow prosthesis score" and the "Mayo elbow performance score". We had 15 female and 9 male patients with a mean age of 67 (± 6) years. RESULTS: All 24 patients achieved very good results based on the used scores with a mean of 97 points each with a maximum performance of 100 points. The mean range of motion concerning extension and flexion was 92 degrees (range 55 to 115 degrees), concerning pronation and supination 144 degrees (range 100 to 160 degrees). The mean flexion deformity was 19 degrees (range 10 to 50 degrees), the mean maximum flexion was 112 degrees (range 90 to 130 degrees). During the follow-up we had two partial ruptures of the triceps tendon, one temporary lesion of the ulnar nerve with complete recovery after surgical revision and one postoperative haematoma which needed surgical treatment. One patient needed revision surgery and resection arthroplasty due to a deep infection, but received a new prosthesis after two months. We recorded no radiographic loosening or other mechanical problems. CONCLUSIONS: Due to the good functional outcome and pain relief of patients treated by total elbow replacement, we suggest that total elbow arthroplasty is a reasonable treatment option for complex acute and chronic injuries of the elbow in elderly patients.

[Current treatment concepts for mid-shaft fractures of the clavicle - results of a prospective multicentre study]. / Aktuelle Behandlungskonzepte der Klavikulaschaftfraktur - Ergebnisse einer prospektiven Multicenterstudie.

BACKGROUND: Mid-shaft clavicular fractures are mainly treated conservatively with an average incidence of non-union in 4.5 %. Gender, age, grade of fragment dislocation and comminution are risk factors to develop a pseudarthrosis. In contrast to patients who where operated on, conservative treatment was also associated with a higher complication rate and pain level as well as a poor shoulder function and cosmetic result. Therefore more patients are treated operatively, especially modern minimally invasive techniques have been developed and remain as equals to the standard plate fixation. PATIENTS/MATERIAL: Within a period of 24 months patients with a mid-shaft clavicular fracture were included into a prospective, non-randomised multicentre study. A modified AO classification was used. Patients were treated either conservatively, by plating or intramedullary nailing. Pain level, cosmetic result, shoulder function and complication rate were documented as well as the influence of the profession on the therapeutic strategy and duration of unfitness for work. RESULTS: 120 patients (95 male, 25 female) were included in the study. Fractures were caused in 35 (29 %) by a direct, in 85 (71 %) by an indirect trauma mechanism. Because of their lower grade fractures with overlapping fragments 47 (39 %) patients were treated conservatively with a figure-of-eight-bandage. Patients with higher graded fractures and fragment displacement were stabilised either by intramedullary nailing (n = 20, 27 %) or plate fixation (n = 53, 73 %). 96 (80 %) patients were examined at a follow-up of eight weeks and eight months after injury. Early freedom from pain (p = 0.014), a better cosmetic result (p = 0.1) and an improved subjective (p = 0.004) and objective (p = 0.01) shoulder function were statistically significant in operated patients. Clavicle shortening was often found to be significant in conservatively treated patients (p = 0.006). Duration of unfitness for work depended on the physical activity in the job. The complication rate was 15 % for each therapy, non-union was detected in one (0.8 %) patient. CONCLUSION: Mid-shaft clavicular fractures have to be classified by the criteria contact and number of fragments. Advantages of operative procedures are early freedom from pain and shoulder function recovery. Non-displaced low grade shaft fractures without shortening should be treated conservatively, whereas displaced low-grade shaft fractures have a better result after intramedullary nailing. Plate fixation should be predominantly used in dislocated and comminuted fractures as well as in patients with a high level of physical activity in their jobs.

[Functional results after osteosynthesis of the distal humerus fracture with an anatomically precontoured, angular-stable double plate system]. / Funktionelle Ergebnisse nach winkelstabiler Osteosynthese der distalen Humerusfraktur mit einem anatomisch präformierten Doppelplattensystem.

AIM: The aim of this study was to evaluate the functional results and determine/record the complications after treating distal humerus fractures with an anatomically precontoured and angular-stable double plate system (LCP Distal Humerus Plates, Synthes GmbH, Umkirch). METHOD: 51 patients (30 female, 21 male) with 52 fractures of the distal humerus and a mean age of 51 years (14-94) were prospectively recorded over a period of 42 months and treated by open reduction and internal fixation using the above-mentioned LCP Distal Humerus Plates System. Follow-up was performed in 44 patients with 45 fractures after a mean of 13 months (6-24). According to the classification system introduced by the "Arbeitsgemeinschaft für Osteosynthesefragen" (AO [Association for the study of internal fixation, ASIF]) there were six A fractures (13.3%), five B fractures (11.1%) and 34 C fractures (75.5%). The AO/ASIF rate of type C3 fractures was 53%. Seven fractures were grade I (15.6 %) and three fractures grade II (6.7%) open. In addition to clinical examination and measuring range of motion (ROM), functional results were evaluated using the Mayo elbow performance score (MEPS) and the disabilities of the arm, shoulder and hand score (DASH). RESULTS: Using the MEPS, excellent results were achieved in 19 patients (43.2%), good in 23 (52.3%), fair and poor each in one. Mean MEPS was 87.5 +/- 11.8 points (50-100). The mean DASH score reached 14.2 +/- 19.9 (0-65.8). Having a mean extension deficit of 10 +/- 14.1 degrees (0-40 degrees) and flexion up to 127.5 +/- 17.2 degrees (80-145 degrees), the mean ROM was 110 +/- 23.8 degrees (50-145 degrees). A primary stable osteosynthesis which allows early physiotherapy was gained in 38 fractures, in seven cases additional immobilisation was carried out (10 to 28 days). Postoperative complications were seen in eleven patients (24.4%). Overall revision surgery was necessary in nine cases. CONCLUSION: By using the anatomically precontoured and angular-stable LCP distal humerus plates system a stable osteosynthesis allowing early physiotherapy is achieved in the majority of patients. Due to early initiation of physical therapy the functional results might be improved. Despite using the LCP system complications at the distal humerus fracture side were seen frequently, emphasising the challenging surgical procedure and demonstrating the need for further implant and surgical procedure improvement.

[Medical care reality in trauma surgical clinics in Germany. A survey of the professional committee of the German Society for Trauma Surgery]. / Zur Versorgungsrealität unfallchirurgischer Kliniken in Deutschland. Eine Umfrage des Berufsständischen Ausschusses der Deutschen Gesellschaft für Unfallchirurgie.

Due to revised conditions of medical care in Germany, in particular the introduction of the newly designated specialist for orthopaedics and trauma surgery, the working conditions in trauma surgical clinics in Germany has changed. In May 2008 the professional committee of the German Trauma Society conducted a survey at the 729 trauma surgical clinics and departments in order to establish the true level of care at these particular sites. The results of the 90,000 variables presented in the following article, reflect the changes in trauma care as well as in the medical care structures and emphasize the increased work load. In particular the lack of qualified candidates underlines the main explanation for vacant posts and is also evaluated in this article.

[Triage systems in central emergency units]. / Triage-Systeme in der Zentralen Notfallaufnahme.

Central emergency units were established for medical and economic reasons in many German hospitals. The huge number of patients requiring treatment more or less urgent led to an implementation of triage-systems, which are known from abroad. Five of those triage-systems with different approaches are going to be presented below. The Manchester triage-system is the one of those, which can be transferred to German circumstances the best and is the most common clinical triage-system in Germany. Before implementing the above-mentioned systems to German emergency unit all of them need further development. Furthermore a scientific verification of the efficiency and the safety of triage-systems is necessary.

Effects of different artificial insemination techniques and sperm doses on fertility of normal mares and mares with abnormal reproductive history.

The effects of different artificial insemination (AI) techniques and sperm doses on pregnancy rates of normal Hanoverian breed mares and mares with a history of barrenness or pregnancy failure using fresh or frozen-thawed sperm were investigated. The material included 187 normal mares (148 foaling and 39 young maiden mares) and 85 problem mares with abnormal reproductive history. Mares were randomly allotted into groups with respect to AI technique (routine AI into the uterine body, transrectally controlled deep intracornual AI ipsilateral to the preovulatory follicle, or hysteroscopic AI onto the uterotubal junction ipsilateral to the preovulatory follicle), storage method of semen (fresh, frozen-thawed), AI volume (0.5, 2, 12 ml), and sperm dose (50 x 10(6) or 300 x 10(6) progressively motile sperm (pms) for fresh semen and 100 or 800 x 10(6) frozen-thawed sperm with >35% post-thaw motility). The mares were inseminated once per cycle, 24 h after hCG administration when fresh semen was used, or 30 h for frozen-thawed semen. Differences in pregnancy rates between treatment groups were analyzed by Chi-squared test, and for most relevant factors (insemination technique, mare, semen, and stallion) expectation values and confidence intervals were calculated using multivariate logistic models. Neither insemination technique, volume, sperm dose, nor mare or stallion had significant effects (P > 0.05) on fertility. Type of semen, breeding mares during foal heat, and an interaction between insemination technique, semen parameters, and mares did have significant effects (P < 0.05). In problem mares, frozen semen AI yielded significantly lower pregnancy rates than fresh semen AI (16/43, 37.2% versus 25/42, 59.5%), but this was not the case in normal mares. In normal mares, hysteroscopic AI with fresh semen gave significantly (P < 0.05) better pregnancy rates than uterine body AI (27/38, 71% versus 18/38, 47.3%), whereas in problem mares this resulted in significantly lower pregnancy rates than uterine body AI (5/15, 33.3% versus 16/19, 84.2%). Our results demonstrate that for problem mares, conventional insemination into the uterine body appears to be superior to hysteroscopic insemination and in normal mares, the highest pregnancy rates can be expected by hysteroscopic insemination.

Cytoplasmic changes in relation to nuclear maturation and early embryo developmental potential of porcine oocytes: effects of gonadotropins, cumulus cells, follicular size, and protein synthesis inhibition.

Morphological and biochemical changes indicative of cytoplasmic maturation in relation to nuclear maturation progression and early embryo developmental potential was studied. Fluorescently labeled microfilaments and cortical granules were visualized by using laser scanning confocal microscopy. The mitogen-activated protein (MAP) kinase phosphorylation and cyclin B1 levels were revealed by Western blot. With the maturation of oocytes, cortical granules and microfilaments were localized at the cell cortex. A cortical granule-free domain (CGFD) and an actin-thickening area were observed over both the MII spindle of a mature oocyte and chromosomes of a nocodazole-treated oocyte, suggesting that chromosomes, but not the spindle, determined the localization of CGFD and actin-thickening area. In oocytes that are incompetent to resume meiosis, as indicated by the failure of germinal vesicle breakdown (GVBD), peripheral localization of cortical granules and microfilaments, phosphorylation of MAP kinase and synthesis of cyclin B1 did not occur after 44 hr in vitro. These cytoplasmic changes were also blocked when GVBD of meiotically competent oocytes was inhibited by cycloheximide. Culture of oocytes in a chemically defined medium showed that biological factors such as gonadotropins, cumulus cells and follicle size affected both nuclear and cytoplasmic maturation as well as embryo developmental potential. Absence of gonadotropins or removal of cumulus cells alone did not significantly influence GVBD or cyclin B1 levels, but decreased the final maturation and developmental ability of oocytes. A combination of gonadotropin absence and cumulus removal decreased GVBD, MAP kinase phosphorylation and embryo development. A high proportion of oocytes derived from small follicles were able to resume meiosis, synthesize cyclin B(1), phosphorylate MAP kinase and translocate CGs, but their maturation and embryo developmental ability were limited. Removal of cumulus cells from small follicle-derived oocytes severely affected their ability to undergo cytoplasmic and nuclear maturation.

Production of nuclear transfer-derived swine that express the enhanced green fluorescent protein.

The ability to add or delete specific genes in swine will likely provide considerable benefits not just to agriculture but also to medicine, where pigs have potential as models for human disease and as organ donors. Here we have transferred nuclei from a genetically modified fibroblast cell line to porcine oocytes, matured in vitro under defined culture conditions, to create piglets expressing enhanced green fluorescent protein. The nuclear transfer-derived piglets were of normal size, although some mild symptoms of "large offspring syndrome" were evident. These experiments represent a next step towards creating swine with more useful genetic modifications.

Development of porcine embryos and offspring after intracytoplasmic sperm injection with liposome transfected or non-transfected sperm into in vitro matured oocytes.

The objective of this study was to evaluate in vitro and in vivo development of porcine in vitro matured (IVM) porcine oocytes fertilised by intracytoplasmic sperm injection (ICSI) and the possibility of producing transgenic embryos and offspring with this procedure. Activated ICSI oocytes had a higher pronuclear formation than non-activated ICSI oocytes (mean 64.8+/-17.3% vs 28.5+/-3.4%, p<0.05). When the zygotes with two pronuclei were cultured to day 2, there was no difference (p<0.05) in the cleavage rate (mean 60.0+/-7.0% vs 63.3+/-12.7%) between the two groups. The blastocyst rate in the activation group was significantly higher than that in the non-activation group (mean 30.0+/-11.6% vs 4.6+/-4.2%, p<0.05). After injection of the sperm transfected with DNA/liposome complex, destabilised enhanced green fluorescent protein (d2EGFP) expression was not observed on day 2 in either cleaved or uncleaved embryos. But from day 3, some of the embryos at the 2-cell to 4-cell stage started to express d2EGFP. On day 7, about 30% of cleaved embryos, which were in the range of 2-cell to blastocyst stage, expressed d2EGFP. However, for the IVF oocytes inseminated with sperm transfected with DNA/liposome complex, and for oocytes injected with sperm transfected with DNA/liposome complex, and for oocytes injected with DNA/liposome complex following insemination with sperm not treated with DNA/liposome complex, none of the embryos expressed d2EGFP. Sixteen day 4 ICSI embryos derived from sperm not treated with DNA/liposome complex were transferred into a day 3 recipient. One recipient delivered a female piglet with normal birthweight. After transfer of the ICSI embryos derived from sperm transfected with DNA/liposome complex, none of the four recipients maintained pregnancy.

Porcine oocyte activation induced by a cytosolic sperm factor.

It is not known how the fertilizing sperm elicits the release of Ca(2+) from the oocyte's intracellular stores. We investigated whether a crude extract isolated from boar sperm could induce the Ca(2+) release and trigger subsequent early and late activation events upon injection into matured porcine oocytes. The sperm extract induced an immediate rise in the intracellular free Ca(2+) concentration in all oocytes tested, which was followed by repetitive Ca(2+) transients in 11 out of 14 oocytes. Heat or trypsin treatment of the extract totally abolished the Ca(2+) releasing activity of the sperm factor. The injected oocytes showed cortical granule exocytosis, they resumed meiosis and entered first interphase: pronuclei were formed in 89.2% (132/148) of the cases. Pronuclear formation was accompanied by the appearance of a new 22 kDa protein as normally seen at fertilization. Of the successfully injected oocytes 51.7% (105/203) cleaved and 2.0% (4/203) developed to the blastocyst stage after being cultured for 7 days in NCSU 23 medium. Injection of the carrier medium could not trigger these changes. The results indicate that the sperm might activate porcine oocytes by introducing a soluble factor into the oocyte's cytoplasm after gamete fusion.

[Acute injury to the lateral ligament of the ankle joint in the athlete]. / Die akute Aussenbandverletzung des Sprunggelenks beim Sportler.

The ankle sprain is one of the most common injuries in sports. It is useful to classify the grade of injury clinically. Stress x-rays, stress ultrasound or radiographic examinations are not necessary. Based on the analysis of 24 controlled studies we conclude that functional treatment is sufficient. It does not lead to higher subjective or objective instability nor to a greater number of reinjuries. Functional treatment has no complications. Although controlled studies about the treatment of athletes are missing, but there is no reason for a different treatment in athletes.

[Mechanical dynamic ankle passive motion for physical prevention of thrombosis? Changes in hemodynamics in the lower pressure system with new dynamic splints]. / Mechanische Sprunggelenksbewegungsschiene zur physikalischen Thromboseprophylaxe? Veränderungen der Hämodynamik im Niederdrucksystem mit neuen Bewegungsschienen.

The use of mechanical ankle exercise devices with continuous passive motion (CPM) of the ankle joint can improve venous reflow in the lower limbs after operations. Duplex ultrasonography allows the observations of blood flow velocity and flow volume during continuous movement of the devices. We tested two different CPM devices for ankle movement in a preclinical study on 10 healthy, uninjured people and saw the following changes in the deep venous system in the common femoral vein: after 5 min of motion the velocity of the venous reflow was increased to 112.5% and the flow volume passing the femoral vein to 123% of the initial mean values. After 15 min of motion the devices led to an increase of the venous reflow velocity to 125% and of flow volume to 143% of the baseline values in the femoral vein. These positive effects were still evident even 15 min after the devices have been turned off.

Immunohistological analysis of Hodgkin's and Sternberg-reed cells: detection of a new antigen and evidence for selective IgG uptake in the absence of B cell, T cell and histiocytic markers.

To help clarify the origin and nature of Hodgkin's (H) and Sternberg-Reed (SR) cells, three different sets of experiments were performed. First, it was shown that cytoplasmic gamma, kappa, lambda occur not only in H and SR cells, but also in polymorphic tumor cells of epithelial, neurogenic, and lymphoid origin. Furthermore, human IgG that was injected i.v. into rats penetrated many rat liver cells, whereas injected human alpha 1-antitrypsin did not. Second, staining of frozen sections revealed that H and SR cells lack surface immunoglobulin and peripheral T-cell antigen. Third, an antiserum raised against the L 428 cell line (derived from Hodgkin's disease) and absorbed with human serum and normal cells did not react with any cells of tonsil tissue (lymphoid cells, histiocytes, and interdigitating reticulum cells), whereas it reacted strongly with the L 428 cell line cells and with H and SR cells of 10 different cases. In all ten cases, the antiserum stained the surface of H and SR cells; in two cases, it also stained the nucleoli and some chromatin spots in H and SR cells. The results obtained in these experiments indicate that H and SR cells are not closely related to lymphoid cells, histiocytes, or interdigitating reticulum cells. The findings also suggest that H and SR cells express one or more antigens that have not yet been detected on or in normal cells.

Immunohistologic analysis of the organization of normal lymphoid tissue and non-Hodgkin's lymphomas.

Hoping to improve the systems for identifying and classifying normal and malignant lymphoid subpopulations, frozen and paraffin sections of nonmalignant lymphoid tissue and of malignant lymphomas were immunostained for surface (S) and cytoplasmic antigens using the peroxidase-antiperoxidase method. Primary follicle cells and follicle mantle cells known to be part of the recirculating B-cell pool were found to be constantly Ia and C3 receptor (C3R) positive, mostly SIgM and SIgD positive and cytoplasmic immunoglobulin (CIg) negative. The light zone of germinal centers (GC), which is rich in centrocytes, contained a large number of T cells and showed the well-known intercellular Ig network pattern; the dark zone, containing densely packed centroblasts, was usually free of T cells, but was bordered ay a mantle-like accumulation of T cells. Usually only some of the GC cells were definitely positive for SIg and CIg of different classes. All cells reacted positively for Ia and C3R. In areas described by other authors as containing marginal zone cells, cells densely bearing SIgM and deficient in SIgD were detected. The immunoblasts of the hyperplastic plasma cell reaction usually contained CIg. Cells from chronic lymphoid leukemia sections that immunostained for SIgM and SIgD were interpreted as representing a neoplasm of recirculating B cells expressing SIgM and SIgD. The immunohistologic architecture of follicular centroblastic/centrocytic lymphoma showed a more or less close similarity to the organization of secondary follicles. Lymphomas whose cells resembled reactive centrocytes were strongly SIgM positive and SIgD negative or only weakly SIgD positive. CIg was demonstrable in nearly 90% of the lymphomas whose cells resembled centroblasts and in 70% of the lymphomas whose cells resembled immunoblasts of the plasma cell reaction. Finally, immunohistologic staining results from a T-zone lymphoma are presented, which confirm that this lymphoma was composed of a neoplastic T zone and a non-malignant B zone.