[Risk assessment]

The aim of preoperative risk analysis is to reduce postoperative morbidity and mortality by identification of compromised organ function which can be improved by targeted preoperative measures and problem-oriented postoperative therapy. Ideally, therefore, preoperative risk assessment, influences the timing of the surgical procedure, the choice of the surgical approach, and the postoperative management. Identification of preexisting relevant disorders that may influence the postoperative course is an essential prerequisite of risk analysis. While preoperative risk analysis today gains in importance with the increasing extent of elective surgical procedures, preoperative risk evaluation still plays a minor role in the emergency situation when the given patient-dependent risk usually has to be accepted. Objective risk evaluation depends on the general and nutritional status, the pulmonary, cardio-vascular, hepatic, and renal function, and the cooperation of the patient. These factors, however, clearly have to be seen in relation to the type and extent of the planned surgical procedure. The selection of additional tests of organ function, exceeding the standard tests required prior to any surgical intervention, must be guided by the extent of the planned surgical procedure, the physiologic alterations associated with the surgical procedure, and the suspected underlying organ dysfunction. Generally accepted multi-factorial classification systems to identify patients at risk for a wide spectrum of surgical procedures are currently not available. Using the model of esophagectomy in patients with esophageal cancer we could, however, demonstrate that a quantitative assessment of the peri- and postoperative risk based on preoperatively available physiologic parameters is possible and markedly reduces postoperative mortality when applied prospectively. The development and validation of similar risk-score systems for other surgical procedures should be considered.

Dose-response relationship of complementary radiotherapy following four cycles of combination chemotherapy in intermediate-stage Hodgkin's disease

PURPOSE

To determine the appropriate irradiation dose after four cycles of modern combination chemotherapy in nonbulky involved field (IF/BF) and noninvolved extended-field (EF/IF) sites in patients with intermediate-stage Hodgkin's disease (HD).

MATERIALS AND METHODS

HD patients in stage I to IIIA with a large mediastinal mass, E stage, or massive spleen involvement were treated with two double cycles of alternating cyclophosphamide, vincristine, procarbazine, and prednisone (COPP) plus doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) followed by EF irradiation in two successive trials (HD1 and HD5). In the HD1 trial (1983 to 1988), 146 patients who responded to chemotherapy were randomized to receive 20 Gy (70 patients) or 40 Gy (76 patients) of EF irradiation in all fields outside bulky disease sites. A cohort of 111 patients who fulfilled the same inclusion criteria in the subsequent trial HD5 (1988 to 1993) were treated with 30 Gy. Bulky disease always received 40 Gy.

RESULTS

Freedom-from-treatment-failure (FFTF) and survival (SV) curves showed no differences between the 20-, 30-, and 40-Gy groups. However, acute toxicities were more frequent in the 40-Gy arm. Analysis of relapse patterns showed that 18 of 26 relapsing patients either failed to respond in initial bulky sites (n = 5) or had an extranodal relapse (n = 9) or both (n = 4). After 5 years, the cumulative risk for relapse in bulky sites is 10%, despite 40 Gy of radiation.

CONCLUSION

Our results strongly suggest that there is no relevant radiotherapy dose effect in the range between 20 Gy and 40 Gy in IF/BF and EF/IF after 4 months of modern polychemotherapy in patients with intermediate-stage HD. Relapse patterns indicate that patients destined to relapse need more systemic, rather than local, treatment. Based on our data, we conclude that 20 Gy is sufficient in EF/IF of intermediate-stage HD following four cycles of modern polychemotherapy.

Distinct mechanisms of immunosuppression as a consequence of major surgery

Altered host defense mechanisms after major surgery or trauma are considered important for the development of infectious complications and sepsis. In the present study, we demonstrate that major surgery results in a severe defect of T-lymphocyte proliferation and cytokine secretion in response to coligation of the antigen receptor complex and CD28. During the early postoperative course, reduced cytokine secretion was observed for interleukin-2 (IL-2), gamma interferon, and tumor necrosis factor alpha, which are associated with the Th1 phenotype of helper T lymphocytes, and for IL-4, the index cytokine of Th2 cells. During the late postoperative course, T-cell cytokine secretion increased to normal levels. Production of the anti-inflammatory cytokine IL-10 was altered, with different kinetics being selectively elevated during the late postoperative course. In contrast, the capacity of peripheral blood monocytes to present bacterial superantigens and to stimulate T-cell proliferation was normal or enhanced after surgery despite a significant loss of cell surface HLA-DR molecules. Thus, the level of major histocompatibility complex class II protein expression does not appear to predict the antigen-presenting capacity of monocytes obtained from surgical patients with uneventful postoperative recovery. Secretion of IL-1beta and IL-10 by endotoxin-stimulated peripheral blood monocytes was increased at different time points after surgery. Major surgery therefore results in a distinct pattern of immune defects with a predominant defect in the T-cell response to T-cell receptor- and CD28 coreceptor-mediated signals rather than an impaired monocyte antigen-presenting capacity. Suppression of T-cell effector functions during the early phase of the postoperative course may define a state of impaired defense against pathogens and increased susceptibility to infection and septic complications.

Sequential high-dose therapy and autologous stem cell transplantation for treatment of mantle cell lymphoma

BACKGROUND

Mantle cell lymphoma (MC) is not curable with conventional chemotherapy. To improve the prognosis of patients with this disease, we prospectively studied an intensive sequential therapy consisting of the Dexa-BEAM regimen (dexamethasone, BCNU, etoposide, ara-C, melphalan) followed by myeloablative therapy with autologous stem cell reinfusion.

PATIENTS AND METHODS

Nine consecutive patients with stage III/IV MC were included. Two had untreated disease, four were in first remission, whereas three had more advanced disease. All patients underwent one to two cycles of Dexa-BEAM chemotherapy to reduce the tumor load and to mobilize peripheral blood progenitor cells (PBPC). Subsequently, patients were treated with high-dose radiochemotherapy followed by PBPC reinfusion and were prospectively analyzed for residual disease by clinical methods as well as by PCR amplification clonal CDRIII rearrangements.

RESULTS

With an overall response rate of 100%, the initial Dexa-BEAM cycles effectively reduced the tumor load. All patients proceeded to high-dose therapy and subsequent stem cell rescue. Engraftment was prompt, and procedure-related deaths did not occur. With a median follow-up of 12 (3-33) months post transplant, all patients are alive in continuing clinical and molecular remission.

CONCLUSIONS

Sequential intensive therapy consisting of Dexa-BEAM and high-dose radiochemotherapy appears to be a highly effective treatment for patients with MC. However, the data are still preliminary, and larger patient numbers and a longer follow-up are required.

Expression of the gap junction protein connexin43 in the subependymal layer and the rostral migratory stream of the mouse: evidence for an inverse correlation between intensity of connexin43 expression and cell proliferation activity

Connexins constitute the channel-forming proteins of gap junctions. Gap junctions are considered to be involved in the regulation of cell proliferation. To verify this hypothesis for connexin43, the most abundant connexin in brain tissue, we have analyzed the expression of this gap junction protein in the subependymal layer and the rostral migratory stream of the murine telencephalon. These regions reveal high proliferative activity, even during postnatal stages and in adulthood. Proliferating cells were labeled in vivo by means of the bromodeoxyuridine method and were later processed for double immunocytochemistry by using an antibody to connexin43. The relationship between connexin43 expression and cell proliferation was also determined in primary cell cultures of olfactory bulbs from newborn mice. The intercellular coupling efficiency of cultured bulbar cells was also analyzed by dye-transfer experiments in combination with the bromodeoxyuridine technique. In the rostral migratory stream, connexin43 was upregulated during postnatal development, coinciding with a decrease of BrdU incorporation. Comparative quantification of the intensity of connexin43 immunoreactivity by confocal laser microscopy and of BrdU-labeled cells showed a clear reverse correlation between connexin43 expression and cell proliferation in the rostral migratory stream during postnatal development. A marked reverse correlation of both parameters was also observed in primary cell cultures from olfactory bulbs at day 6 after seeding.

Boerhaave's syndrome: analysis of the literature and report of 18 new cases

Postemetic spontaneous rupture of the esophagus is an intrathoracic disaster which is generally lethal if untreated. The tragedy seems to strike more often than commonly suspected. The current literature review focuses on publications since 1980 and includes the retrospective review of 18 additional patients treated in our hospital for spontaneous rupture of the esophagus. Frequently, a wide variety of unspecific symptoms has led to the mistaken diagnosis of an acute abdomen, pancreatitis or cardiac arrest. About 40% of the patients with spontaneous rupture of the esophagus presented a history of alcoholism or heavy drinking and 41% suffered from gastroduodenal ulcer disease. Pain (83%) and vomiting (79%) often associated with dyspnea (39%) and shock (32%) are the major symptoms. This unspecific symptomatology delayed the correct diagnosis of the Boerhaave's syndrome and resulted in a significant complication rate. The mortality rate associated with Boerhaave's syndrome was 50% from the first successful surgical repair in 1947 by Barrett to 1980. After 1980, however, the mortality rate dropped to 31%, because of earlier diagnosis, surgical repair and improvement in intensive care. When surgery is delayed, the prognosis of patients with spontaneous rupture of the esophagus is in general severe.

[Epidermoid cyst of the testis. Organ preserving therapy after suspected ultrasound diagnosis]

Epidermoid cysts of testis are rare benign intratesticular lesions. In case of confirmed pathological criteria enucleation is the therapy of choice. The typical ultrasound pattern of epidermoid cysts recognised in the preoperative diagnostics procedure facilitates planning of an organ-preserving therapy.

Multihandicapped blind and partially sighted children in south Germany. II: Aetiology and pathogenesis

The results of a classification of the aetiology of visual impairment and mental retardation in a series of 239 multihandicapped blind and partially sighted children are reported. These children had been born between 1981 and 1987 and were examined in a population-based study in South Germany. There was marked aetiological heterogeneity. Most prominent were causes related to the perinatal period and late gestation which were found in 41% of the children. Among these, lesions of the visual pathways in preterm children were especially frequent and could be explained by periventricular leukomalacia in a large proportion. The distribution of the major aetiologic groups is different from populations with isolated mental retardation and populations with isolated visual impairment but similar to a Swedish population with spastic quadriplegia. The implications for the prevention of severe multiple impairments in children are discussed.

Determination of rifabutin by high-performance liquid chromatography using on-line concentration and column switching

A simple HPLC method has been developed that allows the sensitive determination of rifabutin (RBT) in human serum using on-line concentration and column switching. After pretreatment of the serum with acetonitrile and centrifugation, the samples were applied to a concentration column (CC) (Zorbax CN). Washing with phosphate buffer-methanol removed most of the contaminating substances. Via a six-port valve the CC was switched to the analytical mode. RBT was separated on a Chromspher RP 8 column (acetonitrile-phosphate buffer pH 7.4/sodium chloride) and determined photometrically at 278 nm. The lower limit of quantification for 200 microliters serum precipitated with 200 microliters acetonitrile and after injection of 2 x 150 microliters was 33 micrograms/l and linearity was observed up to 27 mg/l. Different modes of sample application (single, repeated, and different injection volume portions), as well as washing time, cycle time and different CC materials were investigated.

In-vivo evaluation of random donor platelet concentrates from pooled buffy coats

Random-donor platelet concentrates (PC) prepared from pooled buffy coats have recently been described as an alternative method for platelet preparation. We evaluated such PCs in the clinical setting compared with a standard PC from platelet apheresis. PCs were prepared either from pools of buffy coats (BC-PC) or from single donors (SD-PC) with the cell separator CS-3000 plus. PCs were stored for up to 5 days before transfusion. We compared fresh PC (day 1) with stored (day 2-3) and long-stored PC (day 4-5). For analysis, platelet increment in the recipient was determined immediately and 16-22 h (mean 20 h) after transfusion, corrected for total body area and transfused platelets (CCI). A total of 316 PCs were administered to 36 thrombocytopenic patients suffering from various hematological disorders. Patients with detectable HLA or platelet-specific antibodies or splenomegaly were excluded from the study. Mean platelet content of the PC was 262 x 10(9) for BC-PC and 251 x 10(9) for SD-PC. The 20-h CCI after transfusion of fresh PC was slightly higher with BC-PC than with SD-PC (14.5 versus 11.9; p = 0.19), but values did not differ significantly between the two types of PC on any day of storage. For BC-PC, 20-h CCI decreased with further storage by 30% (10.2; p = 0.02). For SD-PC a decrease by 9% was not significant. In conclusion, platelet concentrates prepared from pools of buffy coats showed excellent transfusion results when administered fresh, but storage decreased the CCI by 30%. No significant difference from PCs from plateletpheresis was observed on any day of storage. Both types of platelet concentrates were capable of sufficient platelet increment even when stored for up to 5 days.

Epirubicin and ifosfamide in metastatic breast cancer

In a randomized, phase II trial, we evaluated the effectiveness of continued chemotherapy with epirubicin/ ifosfamide versus unmaintained treatment interruption in advanced metastatic breast cancer. Three hundred fifty-seven patients were enrolled and 331 were evaluable for response. Complete response was achieved in 25 patients (8%) and partial response in 121 patients (37%). Pretreatment status correlated significantly with response (complete and partial response). While 54% of unpretreated patients responded, only 42% of the patients responded who had been pretreated with adjuvant chemotherapy and 33% who had been pretreated in the metastatic stage of disease; 69 patients (21%) had disease progression. Of 11 patients pretreated in both the adjuvant and metastatic setting, only two responded. Toxicity of treatment was mild, with leukopenia being the treatment-limiting factor. Thrombocyte levels were not altered significantly by treatment. Thus, there seems to be room for dose escalation using granulocyte colony-stimulating factor. There was no considerable cardiotoxicity, central nervous system toxicity, or cystitis observed. The low rate of cardiotoxicity appeared to be related to dose fractionation of epirubicin. After randomization of patients to treatment interruption versus continuation of chemotherapy, a longer relapse-free survival was observed for patients who continued chemotherapy (mean relapse-free survival, 2+ months); however, this did not translate into prolonged survival. The cumulative scores of toxicity and quality of life parameters showed increasing superiority for treatment interruption. Therefore, a strategy of treatment until maximum response and subsequent treatment interruption seems to be superior to treatment continuation.

Significance of cytogenetic findings for the clinical outcome in patients with T-cell lymphoma of angioimmunoblastic lymphadenopathy type

PURPOSE

The aim of this study was to evaluate the significance of cytogenetic findings for the clinical outcome of patients with Angioimmunoblastic Lymphadenopathy (AILD)-Type T-cell lymphoma.

MATERIALS AND METHODS

In a retrospective analysis, the cytogenetic findings of 50 patients with AILD-type T-cell lymphoma were correlated with the frequency of spontaneous and therapy-induced remissions and with survival using the statistical methods of Kaplan and Meier and the model of Cox for multivariate analysis. Treatment was not uniform because the patients were treated in different hospitals during a period of 8 years and because a standard therapy has not yet been established.

RESULTS

The following cytogenetic findings were associated with a significantly lower incidence of therapy-induced remissions and a significantly shorter survival duration: presence of aberrant metaphases in unstimulated cultures (P = .04 for both parameters); clones with an additional X chromosome (P = .0001 and P = .03, respectively); structural aberrations of the short arm of chromosome 1, preferentially involving 1p31-32 (P < .001 and P = .04, respectively); and complex aberrant clones with more than four aberrations (P = .0003 and P = .005, respectively). Multivariate analysis showed that these cytogenetic findings had a significant influence on survival, but therapy modalities did not. Only the presence of complex aberrant clones was an independent prognostic factor. Trisomy 3 had no effect on survival, but patients without trisomy 5 (P = .08) tended to live longer.

CONCLUSION

This is the first study that seems to indicate that cytogenetic findings have prognostic significance in AILD-type T-cell lymphoma. These results must be proven in prospective studies of homogeneously treated patients.

Changes in the apical surface of chloride cells following acclimation of lampreys to seawater

Scanning electron microscopy (SEM) was used to study the changes that occur in the morphological relationships between chloride and pavement cells in the gills during acclimation of young adult lampreys to seawater. Because chloride cells are located predominantly between lamellae and are thus obscured from view, the lamellae were removed with the use of a micromanipulator installed in a SEM. In gills of animals maintained in river water, chloride cells could then be seen to be dislike and typically to form single rows between successive lamellae. After acclimation to seawater, the apical surfaces of chloride cells lose their microvilli and change in shape from small circles to rectangles that extend the full width between successive lamellae. These changes result in an increase in the length of the paracellular pathway between chloride cells. Previous work has shown that the number of strands of the zonulae occludentes sealing this pathway declines under these conditions. This presumably leads to an increase in paracellular permeability of the gill epithelium, thereby providing the low-resistance paracellular shunt required for the passive movement of sodium into the environment during osmoregulation in seawater. The above changes are reversed by transfer of lampreys downward to 10% seawater.

[Preoperative risk and postoperative follow-up in surgery of esophageal carcinoma]

The risk involved in esophagectomy in patients with esophageal cancer is related to the general preoperative status of the patient and to the cardiac, pulmonary and hepatic functions. This can be objectively assessed prior to surgery and quantified by a composite risk score. Strict inclusion of the risk score in the preoperative decision-making process resulted in a marked decrease in postoperative mortality at our institution to 1.8%.

Prognostic factors of resected adenocarcinoma of the esophagus

BACKGROUND

The main purpose of this study was to determine prognostic factors in patients with surgical treatment of adenocarcinoma of the esophagus.

METHODS

Within a 12.5-year period, esophageal adenocarcinoma was resected in 165 patients by radical transhiatal esophagectomy (n = 134) or transthoracic en bloc esophagectomy (n = 31). Tumors were analyzed according to the 1992 UICC classification with respect to pTNM stage, residual tumor (R) status, grading, and ratio of infiltrated to resected lymph nodes (lymph node ratio); both univariate and multivariate analysis of prognostic factors were performed.

RESULTS

The 30-day mortality rate was 6.1%. A complete removal of the tumor was achieved in 83% of the patients. Lymph node metastases were not detected in mucosal cancer (pT1a) but were detected in 18% of submucosal cancer (pT1b), 77% of pT2, 83% of pT3, and 96% of pT4. The overall 5-year survival rate was 34%; for patients without postoperative residual tumor (R0) it was 41%, and for those without lymph node metastases (pN0, R0) 63%. The 5-year survival rate for patients (pN1) with less than 30% invaded lymph nodes was 45%, compared with 0% for more than 30% invaded nodes. Independent prognostic factors for R0 resected patients excluding postoperative fatal outcome were pT and lymph node ratio.

CONCLUSIONS

Long-term survival after resection of esophageal adenocarcinoma is mainly associated with complete tumor removal, limited esophageal wall penetration, and ratio of infiltrated to removed lymph nodes of less than 0.3.

A milestone in ribosomal crystallography: the construction of preliminary electron density maps at intermediate resolution

Preliminary electron density maps of the large and the small ribosomal particles from halophilic and thermophilic sources, phased by the isomorphous replacement method, have been constructed at intermediate resolution. These maps contain features comparable in size with what is expected for the corresponding particles, and their packing arrangements are in accord with the schemes obtained by ab-initio procedures as well as with the motifs observed in thin sections of the crystals by electron microscopy. To phase higher resolution data, procedures are being developed for derivatization by specific labeling of the ribosomal particles at selected locations with rather small and dense clusters. Potential binding sites are being inserted either by site directed mutagenesis or by chemical modifications to facilitate cluster binding on the surface of the halophilic large and the thermophilic small ribosomal particles, which yield the crystals diffracting to highest resolution (2.9 and 7.3 A (1 A = 0.1 nm), respectively). For this purpose, the surface of these ribosomal particles is being characterized and procedures are being developed for quantitative detachment of selected ribosomal proteins and for their incorporation into core particles. The genes of these proteins are being cloned, sequenced, mutated to introduce reactive side groups, mainly cysteines, and overexpressed. In parallel, two in situ small and stable complexes were isolated from the halophilic ribosome. Procedures for their crystal production in large quantities are currently being developed. Models, reconstructed at low resolution from crystalline arrays of ribosomes and their large subunits, are being used for initial low-resolution phasing of the X-ray amplitudes. The interpretation of these models stimulated the design and the crystallization of complexes mimicking defined functional states of a higher quality than those obtained for isolated ribosomes. These models also inspired modelling experiments according to results of functional studies, performed elsewhere, focusing on the progression of nascent proteins.

Achalasia and squamous cell carcinoma of the esophagus: analysis of 241 patients

Achalasia of the esophagus is presumed by many to be a premalignant lesion leading to an increased risk of squamous cell carcinoma. There is disagreement, however, as to the precise risk of malignant degeneration and there is no consensus as to either the need for close surveillance of achalasia patients or the surveillance technique that should be employed. A review of the available literature on the subject has disclosed a wide range of reported cancer risks in achalasia patients, from zero to 33 times that of the normal population. Cancers, when discovered, are often unresectable and the median survival when they are resectable is low. A personal experience with 241 achalasia patients treated during the past quarter of a century disclosed that 9 had carcinoma, for a prevalence of 3.7%. Carcinoma developed in 3 of these 9 while they were under our observation. This translates into one cancer per 1,138 patient-years of follow-up, an incidence of 88 per 100,000 population, and a risk 14.5 times that of the age-adjusted and sex-adjusted general population. Because of the low postresection survival rate if treatment is delayed until carcinoma of the esophagus becomes symptomatic, closer surveillance of achalasia patients is recommended than has been the case. Because it seems unlikely that close endoscopic surveillance will prove to be cost-effective, periodic (every 2 to 3 years) blind brush biopsy warrants further study as a means of surveillance.

Relationships between endothelial cells, pericytes, and osteoblasts during bone formation in the sheep femur following implantation of tricalciumphosphate-ceramic

BACKGROUND

The origin of osteoblasts is still controversial. Whereas several authors consider the stromal fibroblast of the bone marrow as the osteoprogenitor cell, others propose that the osteoblasts can be derived from the "capillary system." The present study examines the replacement of tricalciumphosphate (TCP)-ceramic implanted into an artificial bone defect by newly formed bone. The results support the hypothesis that osteogenic cells can be derived from invading blood vessels.

METHODS

The spongiosa of the trochanter major of sheep was removed and the defect was filled with TCP-ceramic. Two months after surgery the ceramic implants together with the surrounding bone were removed and processed for transmission electron microscopy. Serial ultrathin sections of three newly formed osteons were examined.

RESULTS

The osteons contain one or two small sprouting capillaries, a peripheral layer of osteoblasts, and in between, a network of glycogen-rich cells. Some of the glycogen-rich cells are completely or partly surrounded by the endothelial basal lamina and are thereby characterized as pericytes. Weibel-Palade bodies, which are considered to be a marker of endothelial cells, were occasionally observed in glycogen-rich pericytes.

CONCLUSIONS

Since pericytes differentiate into osteoblasts under in vivo and in vitro conditions, and have thus been regarded as osteoprogenitor cells, the presence of Weibel-Palade bodies in these cells suggest that osteogenic cells can be derived from endothelial cells.

[Extremely severe complication during ESWL caused by unsuspected asymptomatic pheochromocytoma]

In 0.1% the pheochromocytoma is the reason of a systemic hypertension. The symptoms of a persistent or paroxysmal hypertension with headache, excessive sweating and palpitations lead in 90% to the diagnosis pheochromocytoma. Very rarely a patient with pheochromocytoma may be asymptomatic. We introduce a 68-year-old man whose pheochromocytoma primarily rose up while ESWL and furthermore in anaesthesia. The problems to determine the diagnosis will be scrutinized as following.

Structural organization and epithelial cells types of the intestinal diverticula (protopancreas) of ammocoetes of southern hemisphere lampreys: functional and phylogenetic implications

Larvae of the two southern hemisphere lamprey genera, Mordacia and Geotria, possess one and two intestinal diverticula, respectively, each originating at the oesophageal-intestinal junction. These diverticula comprise an inner layer of simple columnar epithelium composed solely of zymogen and mucous cells, a middle layer consisting mainly of a blood sinus, and an outer serosa layer covered by a simple squamous epithelium (mesothelium). The inner surface is highly folded only in Mordacia. The secretion of mucus probably protects the epithelium from the effects of digestive enzymes secreted by the zymogen cells and/or bile, which enters the diverticulum at its tip. Unlike the situation in southern hemisphere lampreys, the zymogen cells of the larvae of holarctic lampreys are located in the anterior intestine, a condition considered to be "primitive". It is thus proposed that intestinal diverticula were developed during the evolution of southern hemisphere lampreys. The relocation of zymogen cells in the diverticula increases the area for these cells, and thus the capacity for the synthesis and secretion of digestive enzymes, particularly in Mordacia where the inner surface is folded.

Cytogenetic findings in 179 patients with myelodysplastic syndromes

Cytogenetic analyses were performed on 266 bone marrow and peripheral blood samples from 179 patients with myelodysplastic syndromes (MDS). According to the FAB classification, 42 patients presented with RA, 18 with RARS, 37 with RAEB, 22 with CMML, and 29 with RAEB-T. Nine patients showed a secondary MDS (S MDS). FAB classification was not available for 22 patients. Clonal karyotype anomalies were found in 92 patients (51.4%). Complex chromosome abnormalities occurred in 17 (18.5%) of them. An evolution of the karyotype was detected in 16 cases (17.4%). Cytogenetically independent cells or cell clones were found in eight patients. Nonclonal chromosome abnormalities were uncovered in 29 (16.2%) of the 179 MDS patients. Consecutive studies were performed in 48 patients and revealed a good correlation of initial karyotype and clinical course. The most frequent single anomalies were 5q- in 29 (31.5%), -7 in 22 (23.9%), trisomy 1q in 14 (15.2%), and +8 in 13 (14.1%) of 92 patients respectively. Our cytogenetic findings are presented in detail and discussed in relation to patients' age, morphological classification, clinical course, and prognostic impact. The contribution of cytogenetic findings to the delineation of multistep pathogenesis of MDS with special emphasis to karyotype instability is demonstrated.

Ultrastructure and protein transport of M cells in the rabbit cecal patch

BACKGROUND

The gut-associated lymphoid tissue of the rabbit cecum includes a single lymphoid patch located close to the ileocecal orifice. Vimentin immunoreactivity, which can now be regarded as a marker for M cells in rabbits, has identified a subpopulation of epithelial cells as M cells in the domes of this patch. The aim of the present study was to demonstrate that these M cells are capable of antigen transport and to characterize their ultrastructure.

METHODS

M cells of the rabbit cecal lymphoid patch were studied by scanning, thin section, and freeze-fracture electron microscopy. The transcytosis across these M cells was investigated using horseradish peroxidase as a soluble tracer protein.

RESULTS

The M cells were concentrated at the flanks of the domes and had long, thick, branched microvilli, a well-developed terminal web, and a deep invagination of their apical membrane. Numerous small vesicles lay beneath the terminal web in close vicinity to the base of the invagination. These vesicles transported the luminally applied horseradish peroxidase through the M cells. In contrast to adjacent enterocytes, the glycocalyx of M cells was thin, stub-like, and had very few glycocalyceal bodies. Bacteria adhered to the surface of M cells and were also found in the apical invagination.

CONCLUSIONS

The M cells of the rabbit cecal lymphoid patch differ from those of Peyer's patches of the small intestine in their ultrastructure and route of antigen transport. These differences might be related to the situations resulting from differences in the microbial populations at these locations.

Large-cell anaplastic lymphoma-specific translocation (t[2;5] [p23;q35]) in Hodgkin's disease: indication of a common pathogenesis?

Chromosomal aberrations are characteristic and specific events; the detection of chromosomal abnormalities often provides information on diagnosis and prognosis of disease. Some patients with large-cell anaplastic lymphoma (Ki 1 lymphoma) have the translocation t(2;5) (p23; q35), involving a possible growth-regulating tyrosine kinase. We found this translocation in 11 patients with Hodgkin's disease of nodular sclerosis and mixed-cellularity types. This finding has implications for the understanding of the relation between large-cell anaplastic lymphoma and Hodgkin's disease, diseases with morphological and immunophenotypical similarities. Study of this translocation may help understanding of the origins of cancer and cancer growth. It also allows a more precise definition of Hodgkin's disease and may be used as an indicator for clonality--which has long been sought.