Human invariant valpha24+ natural killer T cells activated by alpha-galactosylceramide (KRN7000) have cytotoxic anti-tumour activity through mechanisms distinct from T cells and natural killer cells

Human Valpha24 + NKT cells, a subpopulation of natural killer cell receptor (NKR-P1A) expressing T cells with an invariant T-cell receptor (TCR; Valpha24JalphaQ) are stimulated by the glycolipid, alpha-galactosylceramide (KRN7000), in a CD1d-dependent, TCR-mediated fashion. Little is known about Valpha24 + NKT-cell function. The murine counterpart, Valpha14 + NKT cells, appear to have an important role in controlling malignancy. There are no human data examining the role of Valpha24 + NKT cells in controlling human malignancy. We report that Valpha24 + NKT cells have perforin-mediated cytotoxicity against haemopoietic malignancies. Valpha24 TCR, CD1d and alpha-galactosylceramide may all play a role in cytotoxicity but are not absolute requirements. The greatest cytotoxicity was observed against the U937 tumour cell line (95 +/- 5% lysis). THP-1, Molt4, C1R cells and allogeneic mismatched dendritic cells were also sensitive to Valpha24 + NKT cytotoxicity but neither the NK target, K562, nor lymphokine-activated killer-sensitive Daudi cells, were sensitive. These results indicate a killing pattern distinct from conventional major histocompatibility complex-restricted T cells, NK cells and other cytotoxic lymphoid cells previously described. We conclude that human Valpha24 + NKT cells have cytotoxic anti-tumour activity against haemopoietic malignancies through effector mechanisms distinct from conventional T cells and NK cells and that their specific stimulator KRN7000 may have therapeutic potential.

Mesotheliomas with deciduoid morphology: a morphologic spectrum and a variant not confined to young females

Deciduoid mesotheliomas are rare with only four previously reported cases, all affecting the peritoneum of young females. We describe another six cases (three men and three women; age range 52-65 yrs, median 55 yrs; five peritoneal and one pleural). Three patients had an occupational history of asbestos exposure. The deciduoid appearance predominated in four cases, whereas in two it represented a minor component within conventional tubulopapillary epithelioid mesothelioma. All tumors were strongly cytokeratin-positive (including CK5/6) and all showed at least focal staining for thrombomodulin, HBME-1, and calretinin. All were negative for epithelial mucin (D/PAS), CEA, BerEP4, LeuM1 (CD15), CD21, CD35, and S100 protein. Five of six cases (83%) were vimentin-positive and two (33%) were focally positive for alpha-smooth muscle actin. A differential diagnosis of gastrointestinal autonomic nerve tumor (GANT) had been initially considered from the morphology of one case, and we found positivity for some of the "neuronal" markers described in GANTs. This prompted us to apply such a panel to the other five tumors, accepting that the cytokeratin positivity encountered in all of our cases would exclude GANT. All cases of deciduoid mesothelioma (100%) were positive for PGP 9.5 and NSE and four of six (66%) were positive for NKI/C3. Weak focal staining (<5% cells) for synaptophysin was seen in two of six tumors. All cases were chromogranin-negative. All cases examined by electron microscopy showed desmosomes and smooth microvilli without rootlets but no neuroendocrine granules. In conclusion, a deciduoid morphology appears to be part of the histopathologic spectrum encountered in epithelioid mesothelioma. This variant is not confined to female patients and occurs over a wider age range than previously recognized. The overlapping immunophenotype with GANTs illustrates that caution should be exercised when interpreting positivity for "neuronal" markers in this context. An immunohistochemical panel that includes cytokeratins should always be used.

Cell-sorting in aggregates of Dictyostelium discoideum

When Dictyostelium cells are induced to develop between a coverslip and a layer of agarose, they aggregate normally into groups containing up to a thousand cells but are then constrained to form disks only a few cells thick that appear to be equivalent to the three-dimensional mounds formed on top of agarose. Such vertically restricted aggregates frequently develop into elongated motile structures, the flattened equivalent of three-dimensional slugs. The advantage of using this system is that the restricted z-dimension enables direct microscopic visualization of most of the cells in the developing structure. We have used time lapse digital fluorescence microscopy of Dictyostelium strains expressing green fluorescent protein (GFP) under the control of either prestalk or prespore specific promoters to follow cell sorting in these flattened mounds. We find that prestalk and prespore cells expressing GFP arise randomly in early aggregates and then rotate rapidly around the disk mixed with the other cell type. After a few hours, the cell types sort out by a process which involves striking changes in relative cell movement. Once sorted, the cell types move independently of each other showing very little heterotypic adhesion. When a group of prestalk cells reaches the edge of the disk, it moves out and is followed by the prespore cell mass. We suggest that sorting may result from cell type specific changes in adhesion and the consequent disruption of movement in the files of cells that are held together by end-to-end adhesion.

Sphenoid sinus schwannoma treated by endoscopic excision

Schwannomas, arising from the Schwann cells of the nerve sheath, occur very rarely in the sino-nasal tract and histological diagnosis can, sometimes, be difficult. We describe a case of schwannoma of the sphenoidal sinus occurring in a 71-year-old man, who underwent complete excision of the tumour endoscopically. To our knowledge, this is the third case of sphenoid sinus schwannoma reported in the English literature.

Activation of human Valpha24NKT cells by alpha-glycosylceramide in a CD1d-restricted and Valpha24TCR-mediated manner

Vact14NK(natural killer) T cells play an important role in controlling tumors or in preventing autoimmunity in the murine system. Valpha24NKT cells, the human counterpart of Valpha14NKT cells, may contribute to controlling the progression of autoimmune diseases in humans. These findings show the possibility that ligand(s) for these NKT cells can control the above-mentioned pathological conditions. Specific glycolipids such as alpha-galactosylceramide (alpha-GalCer) and alpha-glucosylceramide (alpha-GlcCer) have been identified as ligand(s) recognized by murine Valpha14NKT cells in a CD1d-restricted manner, but it remains unclear whether these glycolipids are ligand(s) for Valpha24NKT cells in humans. To determine whether alpha-glycosylceramide is presented by CD1d molecules in humans, we initially established a Valpha24NKT cell line specific for alpha-glycosylceramide using dendritic cell (DC) like cells from normal peripheral blood mononuclear cells (PBMC) in an autologous mixed leukocyte reaction (auto-MLR) system, and characterized the Valpha24NKT cell line. The Valpha24NKT cells were CD3+ CD4-CD8-Valpha24+Vbeta11+NKRP1A+ and specifically proliferated in response to alpha-glycosylceramide in CD1d-restricted and Valpha24TCR-mediated manner. The phenotypic and functional similarities between murine Valpha14NKT cells and human Valpha24NKT cells suggest that Valpha24NKT cells may play an important role in controlling tumors or in preventing autoimmunity as observed with Valpha14NKT cells.

Clinical application of in vitro expansion of cord blood

Expansion of cord blood (CB) haemopoietic cells has been investigated with the aim of reducing cytopenia following transplantation. We investigated the increase in total nucleated cells, colony-forming cells (CFC), CD34+ cells and long-term culture-initiating cells (LTC-IC) by limiting dilution after a 14-day culture of CB CD34+ cells (5 x 10(3)/ml) with SCF, IL-3, IL-6, GM-CSF and G-CSF all at 10 ng/ml. On average nucleated cells increased 2500-fold, CD34+ cells 39-fold and CFU-GM 49-fold with maintenance of BFU-E. The more primitive LTC-IC expanded on average 2.5-fold. Expansion of a 20% aliquot of a CB donation could provide a 5-7-fold increase in progenitor cells, and a 1570-fold increase in post-progenitor cells compared to an untreated donation.

Dendritic cells stimulate the expansion of bcr-abl specific CD8+ T cells with cytotoxic activity against leukemic cells from patients with chronic myeloid leukemia

The role of T lymphocytes in the control of chronic myeloid leukemia (CML) after bone marrow transplantations has been clearly shown. This effect closely correlates with graft-versus-host disease (GVHD). A specific graft-versus-leukemia (GVL) effect separate from GVHD has been postulated but has been difficult to show. One possible target for specific GVL activity is the bcr-abl fusion protein characteristic of CML. We have investigated the use of normal peptide-pulsed dendritic cells for the generation of cytotoxic, bcr-abl-specific T cells from normal donors. T cells (CD3+, CD8+, TCR alpha beta+, and NK receptor-negative) generated from a normal donor (HLA A24, B52, B59, Cw1) after stimulation with autologous dendritic cells, primed with a 16 mer peptide spanning the b3a2 breakpoint of bcr-abl, lysed CML cells from the peripheral blood of seven patients with CML with the b3a2 breakpoint. CML cells from four patients with only the b2a2 breakpoint were not lysed. Phytohemagglutinin (PHA) blasts derived from peripheral blood of patients with CML were not lysed, suggesting that cytotoxicity was not due to alloreactivity. Blocking experiments with anti-HLA-A,B,C indicated that cytotoxicity was dependent on recognition of major histocompatibility complex (MHC) class I molecules, although cytotoxicity was not MHC-restricted because not all patients shared HLA types with the T-cell donor. Specificity for bcr-abl and absence of alloreactivity was confirmed by the presence of lytic activity against autologous and allogeneic class I HLA-A matched monocytes pulsed with the 16 mer bcr-abl fusion peptide, but not against unpulsed monocytes or monocytes pulsed with other peptides. These results show that bcr-abl-specific T cells with marked cytotoxic activity against CML cells can be generated and amplified from normal donor peripheral blood. Recognition of HLA molecules is essential for cytotoxicity but strict HLA identity is not required.

Is in vitro expansion of human cord blood cells clinically relevant?

Peripheral blood recovery after cord blood (CB) transplantation is delayed compared with marrow. Expansion of CB haemopoietic cells has been investigated with the aim of reducing cytopenia following transplantation. Mature cells, post-progenitors, progenitors and long-term culture-initiating cells (LTC-IC) from expansion products may contribute to peripheral blood recovery. We investigated the increase in total nucleated cells, colony-forming cells (CFC), CD34+ cells and LTC-IC by limiting dilution after a 14 day culture of CB CD34+ cells (5 x 10(3)/ml) with SCF, IL-3, IL-6, GM-CSF and G-CSF all at 10 ng/ml. On average, nucleated cells increased 2500-fold, CD34+ cells 39-fold and CFU-GM 49-fold with maintenance of BFU-E. The more primitive LTC-IC expanded on average 2.5-fold but effects on long-term marrow-repopulating cells (LTRC) during culture are unknown. A practical application of in vitro expansion of CB might be to expand a 20% aliquot of a CB donation and infuse the remainder unmanipulated. This could provide a 5- to 7-fold increase in progenitor cells, an estimated 1570-fold increase in post-progenitor cells and maintenance of LTC-IC compared to an untreated donation. Combined with in vivo post-transplant growth factor therapy this could prompt early peripheral blood recovery after CB transplantation, without significant loss of LTC-IC or donor lymphocytes.

Endothelial cell precursors are normal components of human umbilical cord blood

Endothelial cells are part of the normal bone marrow stroma. We have previously shown human umbilical cord blood (UCB) does not produce stroma in standard long-term cultures. Highly enriched (93-98%) UCB CD34+ cells were cultured for 6 weeks with interleukin-2 and conditioned medium from the 5637 carcinoma cell line (n = 4). The resulting 'fibroblast like' cells were shown to be endothelial by expression of von Willebrand factor (VWF), ICAM-1 (CD54), E-selectin (CD62E) and PECAM (CD31). Endothelial monolayers seeded with CD34+ UCB cells supported expansion of colony forming cells and CD34+ cells. We conclude that endothelial cell precursors circulate in UCB, and may be derived from the CD34+ cell fraction.

Adaptation of African-American cultural and food preferences in end-stage renal disease diets

Emphasis on culturally based and ethnically oriented food selection by nutrition health professionals is needed to effectively plan therapeutic diets. With the influx of numerous ethnic groups into the United States and the merging of cultural practices, it is important for dietitians to become familiar with specific ethnic foods and regional cooking techniques. In this review, the influence of immigration on regional cuisine is documented. Dominant patterns of typical African-American ethnic menus for holidays and special celebrations are revealed. Analysis of common foods in the African-American culture are listed for reference, along with a glossary of ethnic foods. Renal guidelines are presented for various stages of end-stage renal disease. When planning a specific renal diet, African-American ethnic preferences can be incorporated into the meal plan or appropriate substitutions can be recommended. A suggested sample menu for hemodialysis patients that incorporates African-American preferences is included for reference. Health risks also influence current eating trends of the African-American population. Hypertension and obesity are two physiological factors that need to be evaluated and considered when planning renal diets. Literacy skills and appropriate dietary instructional material is discussed. Reference materials developed for nutrition professionals are important and can be used in the planning of renal diets for African-Americans.

Optimal processing of human umbilical cord blood for clinical banking

Human umbilical cord blood (UCB) has been successfully used as an alternative source of allogeneic hematopoietic stem cells for pediatric transplantation. Clinical banking of UCB requires volume reduction and red cell depletion for cost-effective storage. We have compared processing UCB by Ficoll, Percoll, methylcellulose, gelatin, starch, and red cell lysis. As individual UCB collections vary widely in colony forming cell (CFC) and CD34+ cell content, each UCB (n = 26) was processed by three or more techniques in parallel with Ficoll as the "standard" method. Gelatin gave a consistently high recovery of CFC (92%) and CD34+ cells (86%). Between 0.10-2.50% of the leukocytes in gelatin-treated UCB were CD34+ with an intra-assay variation of 2.1%. Combining data from individual experiments, the correlation between CD34+ and CFC content was excellent (r = 0.77). Lysis rated second in terms of CD34+ and CFC recoveries but is not as practical because of the large volumes involved. Ficoll and Percoll came third but are more expensive and more involved techniques. Starch sedimentation proved to be slow, while methylcellulose processing lost over 60% of CFC and CD34+ cells. After gelatin processing, we calculated 70-mL donations of UCB would contain a mean +/- SD of 9 +/- 2 x 10(8) nucleated cells, 32 +/- 18 x 10(5) CD34+ cells, and 20 +/- 12 x 10(5) CFC with greater than 95% red cell depletion. Recent published computer studies suggest that as few as 2 x 10(5) CD34+ cells may be needed for sustained engraftment of allogeneic marrow in adult transplant recipients. We conclude that average 70-mL UCB donations contain sufficient marrow repopulating cells for adult recipients.

Cryopreserved human bone marrow stroma is fully functional in vitro

Human-marrow long-term culture (LTC) enables maintenance of both stromal and haemopoietic elements of normal bone marrow (NBM) in vitro for 4-6 months. Stroma-based cultures are critical for quantitation of long-term culture initiating cells (LTC-IC), the most primitive human haemopoietic cells measurable in vitro. Supply of NBM can be sporadic, and up to 3-4 weeks in culture is required for stromal maturity. Stroma availability for experimental purposes can therefore be limited. Efforts to produce transformed human and transfected murine stromal cell lines comparable to NBM stroma have had some success. As an alternative, we investigated cryopreserved NBM and cryopreserved performed stroma. Function of cryopreserved and control fresh NBM stroma was similar when evaluated for up to 12 weeks in LTC. We have also demonstrated that stroma derived from cryopreserved NBM or performed cryopreserved NBM stroma can sustain third-party haemopoiesis as efficiently as fresh NBM stroma in LTC. Batched cryopreserved stroma is a convenient, rapidly available, source of functional stroma which avoids the logistic difficulties and lack of standardization associated with stroma from fresh NBM. This important advance will enhance the use of stroma-based LTC in studies of human haemopoiesis.

Postoperative spindle cell nodule of the bladder: a diagnostic problem

A case of postoperative spindle cell nodule of the bladder is reported. Initial pathological analysis was interpreted as leiomyosarcoma for which the patient underwent radical cystectomy, but subsequent reviews were consistent with a postoperative spindle cell nodule. Recognition of this benign, yet rare lesion is of significant importance to urologists, pathologists, and to the patient who may undergo extensive surgical procedure unnecessarily.

Analysis of cord blood CD34+ cells purified after cryopreservation

Many practical issues regarding processing blood samples for cord blood banking remain. After cryopreservation, a reduction in clonogenicity has been reported, although it is unknown whether this is associated with lower potential for long-term engraftment. CD34+ cell purification of cryopreserved cord blood (CB) may be important for the clinical application of in vitro expansion. We compared purity, yield, clonogenicity, and growth in long-term stromal-based culture of fresh and cryopreserved CD34+ purified cells (n = 12) using the miniMACS separation system. Mean purity of CD34+ cells was 93% when processed before and 73% when processed after cryopreservation. Fresh CD34+ cells had higher clonogenic potential than cryopreserved cells (45 vs 20%, p < 0.05) in CFU-Mix assays, indicating that progenitor cell loss during cryopreservation is due in part to reduced cloning efficiency of viable CD34+ cells. In long-term culture (LTC) on irradiated normal human bone marrow stroma (n = 7), CFU-GM production in the two groups was the same over 12 weeks, suggesting identical long-term culture-initiating cell (LTC-IC) numbers. We conclude that apparent clonogenic cell loss during cryopreservation is associated with relative sparing of the more primitive LTC-ICs. CFU-Mix assays may therefore underestimate the transplant potential of cryopreserved CB. Purification of CD34+ cells following cryopreservation gives sufficient purity for detailed evaluation of CD34+ cells and for stem cell expansion.

Ciprofloxacin resistant Serratia marcescens endocarditis as a complication of non-Hodgkin's lymphoma

We report a case of endocarditis caused by a ciprofloxacin-resistant strain of Serratia marcescens in a 50-year-old female neutropenic patient with non-Hodgkin's lymphoma which occurred while receiving ciprofloxacin prophylaxis. She made poor progress on first line therapy with azlocillin and gentamicin by bolus injection t.d.s. The infection was finally eliminated by a regimen of continuous infusion of azlocillin and once daily gentamicin.

Elastomeric polytetrapeptide matrices: hydrophobicity dependence of cell attachment from adhesive (GGIP)n to nonadhesive (GGAP)n even in serum

The cross-linked polytetrapeptide matrices based on the repeating amino acid sequences, GGAP, GGVP and GGIP, were prepared and tested for cell adhesion promoting activity in both the absence and presence of fetal bovine serum. For comparison, X20-poly(GVGVP), a matrix previously shown to be a poor support for cell attachment and spreading, was included. In the absence of serum, all three polytetrapeptide-based matrices and the polypentapeptide-based matrix were negative for the adhesion of fibroblasts and endothelial cells. In the presence of serum, various sub-maximal levels of cell adhesion were found for all matrices except for the matrix based on GGAP. An apparent correlation was noted between the degree of cell attachment to the different polytetrapeptide-based matrices and the hydrophobicity of those matrices where increased hydrophobicity results in increased cell attachment. The property of being refractory to ligamentum nuchae fibroblast and human umbilical vein endothelial cell adhesion in the presence of serum indicates a potential use for X20-poly(GGAP) in the development of, for example, additional physical barriers for the prevention of post-surgical and post-trauma adhesions.

The depth profile of electrically induced tectal sustained potential shift responses in the goldfish (Carassius auratus)

Tectal sustained potential shifts (SPSs) were recorded in response to electrical stimulation of the tectal surface in immobilized goldfish using saline-filled glass microelectrodes. The peak amplitudes of surface recorded SPS responses were negative, this negativity declining with increasing tectal depth, reversing in polarity at a depth of ca. 350 microns and subsequently increasing in positivity. These opposing SPS polarities are attributed to field potentials generated by the source and sink of extracellular K+ ([K+]e) redistribution through a functional syncitium of radially connected glia.

Cell adhesion and growth on synthetic elastomeric matrices containing Arg-Gly-Asp-Ser-3

Synthetic elastomeric polypeptide matrices based on the repeating amino acid sequences of elastin have biophysical and biological properties which are favorable for prosthetic materials. An important requirement envisaged for some applications is the ability to support cell adhesion and growth. The X20-poly-(GVGVP), the gamma-irradiation cross-linked elastomeric matrix based on the repeating pentamer Val-Pro-Gly-Val-Gly, and X20-poly[n(GVGVP), (GRGDSP)] containing the covalently incorporated cell adhesion sequence Arg-Gly-Asp-Ser (RGDS) were synthesized. These matrices were tested for their ability to support the adhesion and growth of bovine aortic endothelial cells and of bovine ligamentum nuchae fibroblasts. Adhesion experiments carried out in albumin-containing media showed that matrices containing 60:1, 40:1, and 20:1 ratios of (GVGVP):(GRGDSP) supported maximal cell attachment, that matrices containing 100:1 exhibited an intermediate level of attachment and that matrices composed of 500:1 and (GVGVP) alone were very poor supports for cell attachment. Serum in the media promoted submaximal cell attachment to X20-poly(GVGVP) but did not permit substantial cell growth. Cell growth was supported by matrices having high ratios of (GRGDSP). Ratios of 60:1, 40:1, and 20:1 supported three population doublings of endothelial cells over 3 days resulting in confluent matrix-adherent monolayers. Ratios of 40:1 and 20:1 similarly supported the growth of fibroblasts.

A new type of substratum adhesion structure in NRK cells revealed by correlated interference reflection and electron microscopy

The substratum adherent membrane of NRK cells in vitro has been studied using correlated interference reflection and surface replica electron microscopy. Structures visualized by interference reflection microscopy were identified in the subsequently prepared platinum-carbon replicas of the adherent membranes. Substratum adherent membranes were prepared using a hypotonic shock/cell shearing technique (lysis-squirting). Typically 20% of the original ventral membrane surface area and 50% of the original focal adhesion number were retained. Microfilament bundle termini, clathrin-coated sheets and pits, cytotic vesicles having a ridged surface and groups of membrane associated particles were well preserved in the replicas. Two types of isolated adhesion structures were found after lysis-squirting. In addition to typical elongate focal adhesions containing actin and vinculin, we report the existence of adherent membrane patches lacking microfilament bundles and negative for vinculin labelling, but coated with clathrin and identifiable in interference reflection microscopy as less dark than focal adhesions and having dot, U- or sinusoidal shapes.

Labeling of structural elements at the ventral plasma membrane of fibroblasts with the immunogold technique

We investigated the organization of two structural elements (microfilaments and clathrin coated structures) at the ventral plasma membrane in fibroblasts. The methods employed included exposure of the inner face of the ventral plasma membrane by lysis-squirting, labeling the exposed structures with specific antibodies conjugated with colloidal gold, and platinum-carbon replica techniques. The results demonstrate that this regimen combines good ultrastructural preservation with unambiguous identification of structural elements associated with the plasma membrane. This method is therefore reliable and can be generally used to explore in detail the ultrastructural organization of the plasma membrane.

Committee on the forfeiture of assets in criminal offences of the Howard League of Penal Reform

The profits of illicit drug trafficking have attracted world-wide attention. In 1980, a decision of the House of Lords in the United Kingdom ruled that the English criminal courts had no power to forfeit such profits even though earned by convicted defendants. This lacuna in the law aroused considerable criticism and the Howard League of Penal Reform established an independent committee to propose reforms. Its report will be published shortly. This article discusses some of the issues which the Committee faced, particularly the delicate balance between the interest of the State in ensuring that crime does not pay and a commitment to due process before financial punishments are imposed.

Effects of vitamin A on the behaviour of migratory neural crest cells in vitro

It has been proposed elsewhere that the teratogenic effects of retinoids on craniofacial morphogenesis are caused by a disturbance of the migration of cranial neural crest cells. The effects of 3.5 X 10(−5) M and 3.5 X 10(−6) M-retinol on the migration of avian neural crest cells in vitro have been investigated by monitoring cell morphology, locomotory behaviour, fibronectin distribution and actin-microfilament organization. Retinol retards migration by affecting cell-to-substratum adhesiveness. Cells exposed to medium containing retinol are less adherent to the substratum, and although the cell surface is very mobile, are unable to extend or maintain lamellipodia. As a consequence the cells do not actively translocate. Fibronectin distribution at the cell surface is sparse, possibly as a result of shedding, and actin distribution remains diffuse. At the retinol molarities used all these effects are reversible. Thus cells allowed to recover in normal medium flatten out, display lamellipodia and commence active translocation. Fibronectin becomes organized into a fibrillar array and actin microfilaments become organized into cables. The period needed for this recovery is directly related to the molarity of retinol during the initial exposure; after recovery the retinol-treated cells are virtually indistinguishable from control cells. We propose that in vivo the effects of retinoids might be to impair cell-extracellular matrix interaction, thus impeding a cell's ability to migrate through that matrix. Contrary to previous suggestions, the in vivo effects are probably not in any way ‘specific’ to neural crest cells but are more accurately considered as ‘selective’, in that any cell undergoing migration would be similarly affected.

Fibronectin, intercellular junctions and the sorting-out of chick embryonic tissue cells in monolayer

A hierarchy of relative cohesiveness in monolayer of four different embryonic chick tissues was determined in a previous study. The hierarchy is: corneal epithelium congruent to liver parenchyma greater than pigmented epithelium greater than limb bud mesenchyme. The purpose of this paper is to describe the correlation between these adhesive relationships and, firstly, the amount of the adhesive glycoprotein, fibronectin, associated with the cells and, secondly, the morphology of their intercellular contacts. Fluorescent antibody staining of the cells with anti-fibronectin antibody showed that limb bud mesenchyme cells, the most weakly cohesive, had much more fibronectin than the other cell types. Thus there was a negative correlation between the amount of fibronectin and cellular cohesiveness. Analysis of intercellular contacts by electron microscopy showed that the most strongly cohesive cell types, corneal epithelium and liver parenchyma, were also those that possessed desmosomes.

The sorting out of embryonic cells in monolayer, the differential adhesion hypothesis and the non-specificity of cell adhesion

It has been reported previously that sorting out of chick embryonic liver parenchyma and limb bud mesenchymal cells would take place in monolayer culture. The distribution of cell types obtained (liver formed the internal, discontinuous phase) was interpreted in terms of the differential adhesion hypothesis. It was suggested that, in monolayer, liver cells were more cohesive than limb bud cells. In this paper we set out to extend the previous observations with 2 particular questions in mind: (i) Is sorting out in monolayer a general phenomenon occurring between a wider range of cell types? (ii) Can evidence be provided for or against the interpretation of results in terms of the differential adhesion hypothesis? Sorting-out experiments were conducted on circular hydrophilic islands, on an otherwise hydrophobic substratum. Under these conditions, sorting-out in monolayer was obtained with binary combinations of 4 chick embryonic tissue types: liver parenchyma, limb bud mesenchyme, pigmented epithelium of the eye and corneal epithelium. With every combination but one, the cells of one type surrounded the cells of the other type, generating what we have called a ‘circle-within-a-circle’ configuration. With the remaining combination, liver parenchyma and corneal epithelium, only localized sorting was obtained. The ‘circle-within-a-circle’ configuration is consistent with an interpretation in terms of the differential adhesion hypothesis, according to which the distribution of cells is determined by the relative strengths of cohesions between their lateral surfaces. In direct support of this is the finding from plating the different cell types at sub-confluent density on hydrophilic substrata that limb bud is the cell tye having the weakest lateral cohesion in monolayer. Limb bud surrounded the other 3 tissues on hydrophilic island. A hierachy of lateral cohesiveness between the 4 cell types has been constructed. It is unlikely that the results can be explained in terms of specific cohesion. When plated together at subconfluent density, the 3 epithelial cell types aggregate together to form mixed monolayered islands, suggesting that they share common adhesive mechanisms.

Mutual cohesion and cell sorting-out among four species of cellular slime moulds

Interspecific cell cohesion among 4 species of cellular slime moulds, Dictyostelium discoideum, D. mucoroides, D. purpureum and Polysphondylium violaceum has been studied. Binary mixtures of aggregation-stage cells of the 4 species were shaken in suspension, one species of each pair being labelled with [3H]thymidine. Cell aggregates were sampled at intervals over 24 h and their composition examined by autoradiography. The following results were obtained: (i) Cells of each species were capable of cohesion with those of the other 3 species. (ii) In general cells of both species in any mixture were present in aggregates after 1 h, but were not localized according to species. (iii) Within 8-h aggregates cells of different species were regionally localized, i.e. sorting-out appeared to have taken place. (iv) 24-h aggregates were more varied: in mixtures of Dictyostelium species, the different species were localized within the aggregates; in mixtures of Dictyostelium species with Polsphondylium, there was a tendency for cells of the different species to become segregated into completely separate aggregates. The significance of these results in relation to both previous descriptive work and recent biochemical studies on the mechanism of slime mould cell cohesion is discussed.

An assessment of the accuracy of modern endoscopic diagnosis of oesophageal stricture

The results of 135 fibreoptic endoscopic examinations of oesophageal strictures carried out in a district general hospital are reported. The endoscopic diagnosis was correct in 90 per cent, uncertain in 3 per cent and incorrect in 7 per cent of these cases. This study indicates that endoscopic examination should include tissue sampling; this not only allows a precise tissue diagnosis to be made but also is shown to increase the accuracy of diagnosis. Tissue sampling should include cytological as well as histological material. Analysis of cases of stricture correctly diagnosed has shown that target biopsy and brush cytology each makes a significant contribution to diagnosis. The routine collection of cytological specimens in addition to the more commonly obtained histological specimens in addition to the more commonly obtained histological speciments is strongly advocated. The natural history of malignant oesophageal strictures in this study is reviewd. The mean survival in 58 cases was 6.9 months.

Severe pseudomembranous colitis after lincomycin and clindamycin

Four cases of severe pseudomembranous colitis following the use of lincomycin and clindamycin are described; 2 required emergency total colectomy and 2 died. Cases of such gravity after the use of these drugs have not been previously reported. On hundred and fifty-six orthopaedic cases where clindamycin and lincomycin were used postoperatively are reviewed; 34 had diarrhoea (22 per cent), and 3 of the severe cases occurred in this group. The diagnosis of pseudomembranous colitis may be difficult as the latent period from initiation of drug therapy to commencement of diarrhoea may be as much as 18 days, and that from cessation of drug therapy may be as much as 11 days. The value of early sigmoidoscopy in cases of diarrhoea of obscure aetiology is emphasized, and the characteristic sigmoidoscopic and histological appearances of pseudomembranous colitis are described. As these drugs may produce a lethal condition it is suggested that they should be used with appropriate discretion, especially in the elderly female who appears to be most at risk.

Study of dyspepsia in a general practice as assessed by endoscopy and radiology

Fifty consecutive patients presenting in a general practice with dyspepsia were studied. Each patient was referred for a combined barium-meal examination and cholecystogram, followed by fibreoptic endoscopy of the oesophagus, stomach, and duodenum. Thirty patients had a specific lesion of the upper digestive tract and a further four had gall-bladder disease; of these, 16 required surgical treatment. Endoscopy in the remaining 16 patients showed nine with mucosal abnormalities, leaving only seven patients to be classified as normal.The advantage of having an endoscopy service to supplement radiological investigation of dyspepsia is shown.

An epidemiological study of regional enteritis in the Gloucester area

An epidemiological study has been made of regional enteritis in the Gloucester area during the period from 1 Jan., 1966, to 31 Dec., 1970. There were 19 cases in an average population of 253,000, giving an average incidence of new cases of 1.5 per 100,000 per year. There was a significant peak of cases in the 15–24 age-group. The incidence in men was slightly higher than in women. There was a family history of ulcerative colitis in 2 cases. There were 3 cases of regional enteritis of the large bowel only, all occurring in women. Extensive large- and small-bowel involvement occurred predominantly in the younger patients.