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Dendritic cells (DC) are potent antigen presenting cells that possess the unique ability to stimulate naive T-cells. By studying DC derived from various tissues it has been shown that the morphology, phenotype and function of DC alter as they undergo a complex process of maturation. DC are derived from bone marrow progenitors and circulate in the blood as immature precursors prior to migration into the peripheral tissues. Within tissues DC are specialised in the taking up and processing of antigen so that it may be presented on MHC class II molecules. Upon appropriate stimulation tissue DC undergo further maturation and migrate to secondary lymphoid tissue where they present antigen to T-cells and induce an immune response. Studies of DC maturation in vitro have defined the cytokines regulating their development from CD34+ myelomonocytic progenitors as well as from more mature peripheral blood precursors. An alternative pathway of differentiation from thymic precursors has also been described. As a result of these studies, DC may now be generated and manipulated ex-vivo for clinical applications in oncology, autoimmune disease and transplantation.

In chronic myeloid leukaemia (CML), treatment with interferon alpha IFN-alpha results in loss of the Ph' chromosome in a significant proportion of patients. Most cytogenetic responses occur early at a median of 9 months after initiation of treatment and failure to detect a cytogenetic response within a predetermined period may be a reason for IFN-alpha withdrawal. We report a patient in whom IFN-alpha dosage was initially severely limited by bone marrow suppression but in whom continuing treatment led to a first cytogenetic response only after 53 months. Increasing Ph' negativity over a further 2 years was associated with improving haematological tolerance which permitted IFN-alpha dose escalation and complete cytogenetic remission was achieved at 7 years after diagnosis. This remission has been sustained and has thus followed the most delayed cytogenetic response to IFN-alpha so far reported.

Objectives: (1) To determine serotype-specific IgG antibody responses to reimmunization with pneumococcal polysaccharide vaccine at age 5 years in children with sickle cell anemia and (2) to determine whether continued penicillin prophylaxis had any adverse effects on these responses., Study Design: Children with sickle cell anemia, who had been treated with prophylactic penicillin for at least 2 years before their fifth birthday, were randomly selected at age 5 years to continue penicillin prophylaxis or to receive placebo treatment. These children had been immunized once or twice in early childhood with pneumococcal polysaccharide vaccine and were reimmunized at the time of randomization., Results: Serotype-specific IgG antibody responses to reimmunization varied according to pneumococcal serotype but in general were mediocre or poor; the poorest response was to serotype 6B. The antibody responses were similar in subjects with continued penicillin prophylaxis or placebo treatment, and in subjects who received one or two pneumococcal vaccinations before reimmunization. The occurrence of pneumococcal bacteremia was associated with low IgG antibody concentrations to the infecting serotype., Conclusions: Reimmunization of children with sickle cell anemia who received pneumococcal polysaccharide vaccine at age 5 years induces limited production of serotype-specific IgG antibodies, regardless of previous pneumococcal vaccine history. Continued penicillin prophylaxis does not interfere with serotype-specific IgG antibody responses to reimmunization.

Ultrathin sections of bone marrow cells from two patients with homozygous beta-thalassaemia, two patients with haemoglobin H (HbH) disease, a patient with congenital dyserythropoietic anaemia (CDA) type III and two patients with severe congenital dyserythropoietic anaemia of an unusual type were reacted with mouse monoclonal antibodies against various globin chains and the reaction visualized using a gold-labelled goat antibody against mouse IgG. The multiple rounded intra-erythroblastic inclusions found in homozygous beta-thalassaemia reacted with the monoclonal antibody against alpha-globin chains but not beta-globin chains, thus confirming that they consisted of precipitated alpha-globin chains. The branching intra-erythroblastic inclusions found in HbH disease and CDA type III reacted with the monoclonal antibody against beta-globin chains but not alpha-globin chains, indicating that they consisted of precipitated beta-globin chains. The two patients with severe CDA had been transfusion-dependent since infancy, had a normal alpha:beta globin chain synthesis ratio or parents with normal red cell indices, displayed prominent dysplastic changes in their erythroblasts, and had intra-erythroblastic inclusions resembling those seen in homozygous beta-thalassaemia. However, unlike those in beta-thalassaemia, the inclusions in these two patients did not react with the monoclonal antibody against either alpha- or beta-globin chains. The inclusions reacted with antibody against zeta-globin chains, but detailed studies in one of the patients indicated that the antigen involved was not zeta-globin. These patients have features not reported in the condition known as dominantly inherited inclusion body beta-thalassaemia and appear to suffer from a novel type of CDA in which the intra-erythroblastic inclusions may consist of some non-globin protein or structurally-abnormal alpha-globin chains.

Dendritic cells (DC) are essential for the presentation of antigen in primary immune responses and they develop from CD34+ cells in the bone marrow. Although both granulocyte macrophage colony stimulating factor (GM-CSF) and tumour necrosis factor (TNF) are known to stimulate the development of mature DC from their progenitor (CFU-DL), the function of stem cell factor (SCF) in this pathway remains to be determined. The interactions of SCF with GM-CSF, TNF, interleukin-3 (IL-3) and macrophage colony stimulating factor (M-CSF) in promoting CFU-DL development have now been studied in serum-free cultures of unfractionated as well as progenitor enriched cells from either bone marrow or cord blood. Although SCF alone is without effect on colony formation, it enhances both the numbers and size of DC colonies generated in vitro by GM-CSF and TNF. It acts directly on progenitors and in the presence of GM-CSF can also induce suboptimal DC growth even in the absence of TNF. SCF appears to recruit very early progenitors of a high proliferative potential with the capacity to differentiate into erythroid and myeloid as well as dendritic cell progeny. In combination with other cytokines it may therefore be useful for the ex vivo generation of large numbers of DC for clinical purposes.

Four cases of endometrial extramedullary haemopoiesis are reported, all with associated haematological disease. The diagnoses of a myeloproliferative disorder and thalassaemia trait were made as a consequence of the histological observations and subsequent haematological investigations in two cases. The third case occurred in a patient with an established diagnosis of chronic myeloid leukaemia. The diagnosis of extramedullary haemopoiesis in the final case was made on autopsy material from a patient with multiple myeloma. The endometrium from five other women with known myelofibrosis was examined but extramedullary haemopoiesis was not found. Endometrium from 32 fetuses did not contain haemopoietic elements, excluding the likelihood of the endometrium being a common site for extramedullary haemopoiesis in development. Endometrial extramedullary haemopoiesis is an uncommon finding, but it is worthy of note, as it may herald the presence of an underlying haematological abnormality.

The clinical status of a homogeneous cohort of long-term survivors of allogeneic marrow transplantation was assessed and residual leukaemia was studied by reverse transcription polymerase chain reaction for leukaemia specific BCR-ABL mRNA. The group comprised 34 consecutive patients with CML in chronic phase treated by chemoradiotherapy and transplantation of bone marrow from HLA-identical sibling donors between February 1981 and December 1983 in the joint Hammersmith-Northwick Park programme. The probability of survival at 10 years was 59 +/- 17%. Eighteen of the 19 surviving (95%) patients have Karnofsky scores of 90 or 100% indicative of a good performance status. One of the survivors had evidence of relapse 6.5 years after transplant but has since been restored to complete remission by treatment with interferon-alpha followed by donor leucocyte transfusions. Surprisingly, 2 of the 19 patients who have been in remission for over 10 years have molecular evidence of persisting leukaemic cells. Quantification by competitive PCR indicated that the malignant clone persisted at low levels. The data suggest that the majority of long-term survivors after BMT for CML are in good health and may be regarded as cured. Some long-term survivors, however, may still harbour residual leukaemic cells and continued monitoring for late relapse is warranted. Late relapse is amenable to further therapy with leukocyte transfusions from the original marrow donor.

Carbon exchange rates (CER) and whole-plant carbon balances of beech (Fagus grandifolia) and sugar maple (Acer saccharum) were compared for seedlings grown under low irradiance to determine the effects of atmospheric CO 2 enrichment on shade-tolerant seedlings of co-dominant species. Under contemporary atmospheric CO 2 , photosynthetic rate per unit mass of beech was lower than for sugar maple, and atmospheric CO 2 enrich ment enhanced photosynthesis for beech only. Aboveground respiration per unit mass decreased with CO 2 enrichment for both species while root respiration per unitmass decreased for sugar maple only. Under contemporary atmoapheric CO 2 , beech had lower C uptake per plant than sugar maple, while C losses per plant to nocturnal aboveground and root respiration were similar for both species. Under elevated CO 2 , C uptake per plant was similar for both species, indicating a significant relative increase in whole-seedling CER with CO 2 enrich ment for beech but not for sugar maple. Total C loss per plant to aboveground respiration was decreased for beech only because increase in sugar maple leaf mass counterbalanced a reduction in respiration rates. Carbon loss to root respiration per plant was not changed by CO 2 enrichment for either species. However, changes in maintenance respiration cost and nitrogen level suggest changes in tissue composition with elevated CO 2 . Beech had a greater net daily C gain with CO 2 enrichment than did sugar maple in contrast to a lower one under contemporary CO 2 . Elevated CO 2 preferentially enhances the net C balance of beech by increasing photosynthesis and reducing respiration cost. In all cases, the greatest C lost was by roots, indicating the importance of belowground biomass in net C gain. Relative growth rate estimated from biomass accumulation was not affected by CO 2 enrichment for either species possibly because of slow growth under low light. This study indicates the importance of direct effects of CO 2 enrichment when predicting potential change in species distribution with global climate change.

XM323 represents a novel class of potent inhibitors of human immunodeficiency virus (HIV) protease. In vitro studies have shown that inhibition of this enzyme translates into potent inhibition of replication of HIV type 1 (HIV-1) and HIV-2. The inhibition of virus replication was assessed with three assays designed to measure the production of infectious virus, viral RNA, or p24 antigen. The production of mature infectious virions was measured with a yield reduction assay. By this assay, several strains and isolates of HIV-1 and HIV-2 were shown to be susceptible to XM323 in two lymphoid cell lines (MT-2 and H9) and in normal peripheral blood mononuclear cells, with a concentration required for 90% inhibition (IC90) of 0.12 +/- 0.04 microM (mean +/- standard deviation). The production of HIV-1(RF) RNA was measured with an RNA hybridization-capture assay. With this assay, XM323 was shown to be a potent inhibitor of HIV-1(RF) replication, with an IC90 of 0.063 +/- 0.032 microM. A third measure of virus replication, the production of p24 viral antigen, an essential protein component of the virion, was determined with the AIDS Clinical Trial Group-Department of Defense peripheral blood mononuclear cell consensus assay. This assay was used for expanded testing of XM323 against 28 clinical isolates and laboratory strains of HIV-1. XM323 was shown to be equally effective against zidovudine-susceptible and zidovudine-resistant isolates of HIV-1, with an overall IC90 of 0.16 +/- 0.06 microM.

Protease inhibitors are another class of compounds for treatment of human immunodeficiency virus (HIV)-caused disease. The emergence of resistance to the current anti-HIV drugs makes the determination of potential resistance to protease inhibitors imperative. Here we describe the isolation of an HIV type 1 (HIV-1) resistant to an HIV-protease inhibitor. Serial passage of HIV-1 (strain RF) in the presence of the inhibitor, [2-pyridylacetylisoleucylphenylalanyl-psi (CHOH)]2 (P9941), failed to yield a stock of virus with a resistance phenotype. However, variants of the virus with 6- to 8-fold reduced sensitivity to P9941 were selected by using a combination of plaque assay and endpoint titration. Genetic analysis and computer modeling of the variant proteases revealed a single change in the codon for amino acid 82 (Val-->Ala), which resulted in a protease with lower affinity and reduced sensitivity to this inhibitor and certain, but not all, related inhibitors.

In this study, we have evaluated the usefulness of eight serologic tests in the diagnosis of a Candida tropicalis septicaemia in a patient with acute myeloid leukaemia. Among the tests used, detection of mannose and candida antigen in serum allowed a high degree of suspicion of infection, earlier than the isolation of this species on mycological cultures from blood or oesophagic samples. Detection of anti-C. albicans antibodies was useless but low titres of anti-C. tropicalis antibodies were observed. In spite of early diagnosis and antifungal treatment, the complication of the disseminated candidiasis with a Pseudomonas aeruginosa septicaemia, concluded with the patient's exitus.

Colonies of CD1a+ HLA-DR+/DQ+ CD4+ cells with the functional and some of the structural attributes of Langerhans cells are observed in human bone marrow cultures in semi-solid media and are assumed to be the progeny of an early progenitor, the dendritic/Langerhans cell CFU (CFU-DL). The cytokine-regulated growth of these cells has been studied using a chemically defined serum-free system to culture both unfractionated and highly enriched bone marrow progenitor cell populations. Although unfractionated cell growth was optimal in serum replete cultures with PHA-stimulated leukocyte-conditioned medium (PHA-LCM) suboptimal proliferation of CFU-DL was observed in serum even in the absence of PHA-LCM. No colonies were observed under serum-free conditions when granulocyte-macrophage CSF (GM-CSF), IL-3, granulocyte CSF (G-CSF), and macrophage CSF (M-CSF) were present at levels optimal for granulocyte colony-forming unit (CFU-G) and macrophage colony-forming unit (CFU-M) growth. Addition of IL-1 alpha to these cytokines stimulated a small number of CFU-DL. However, in the presence of GM-CSF and IL-3, TNF-alpha or TNF-beta (5 U/ml) were both highly effective in promoting growth up to 82% of optimal and CFU-G growth was also enhanced at these concentrations. TNF was only active during the first 3 days of culture and higher concentrations of TNF-alpha but not TNF-beta were inhibitory for both CFU-DL and CFU-G. CD34+ cell-enriched populations were also enriched for both myeloid progenitors (CFU-G + CFU-M) and CFU-DL to 36- and 48-fold, respectively, and single cell cultures of CD34+ cells yielded single colonies containing both CD1a+ dendritic cells and CD1a- macrophages. Thus dendritic/Langerhans progenitors in the bone marrow expresses CD34, have a capacity for both macrophage and dendritic cell differentiation, and depend on hemopoietic growth factors and TNF for their further development in vitro.

This paper reports our experience of the use of polythene sheet as a temporary dressing for excised wounds. A prospective randomised double-blind trial was conducted to see whether or not polythene dressing was less painful to remove than our traditional dressing of Jelonet. Polythene was found to be less painful (p less than 0.01). Other advantages of the use of polythene are presented.

The effective coding of data to produce a medical audit relies on agreement between the coders. This study was designed to assess whether coders can agree on codes for diagnosis and operations in a plastic surgery unit. Information from 50 patients was presented to a panel of six coders who were required to code the data using the International Classification of Diseases (ICD-9) and the Office of Population Census Studies (OPCS-4) systems. The results show that agreement between all the panellists occurred in only 32 out of 50 patients for one diagnostic code and 30 out of 50 for one operation code. When a patient had more than one diagnosis or operation, agreement was very much worse. Expert coders produced better results than the medical coders. The results are discussed with reference to other coding systems.

A single layer of surgical gauze applied with adhesive provides a simple and inexpensive dressing for use following hypospadias repair. It splints the penis to the abdomen, supports the wound and secures the catheter while permitting observation and wound care.

A technique for nasal lengthening is described in 3 cases using nasolabial flaps for lining and an island forehead flap for skin reconstruction. It is basically a 2-stage procedure with short hospitalisation.

Secondary alveolar bone grafting in cleft palate patients has been popularised by the Oslo group. Harvesting of the bone graft has been carried out by techniques developed initially for cranio-facial surgery. This paper describes a more refined technique applicable to the requirements of alveolar bone grafting. The Craig bone biopsy set is used to trephine cores of autogenous particulate marrow and cancellous bone from the iliac bone. The method was tested in a cadaver and then applied in 10 clinical cases. The aesthetic and functional results of this technique proved to be superior to the conventional approach.

A new free flap is described based on the deltoid vessels of the acromiothoracic axis. The flap is comprised of the clavicular head of pectoralis major muscle with overlying skin. It is also possible to harvest vascularised clavicular bone with the flap. The vascular anatomy is reviewed and the technique of raising the flap described. Its clinical application is illustrated with five cases. Four of these were intra-oral reconstructions and the fifth a composite osteo-musculocutaneous flap to a lower limb following trauma.

The response of bone marrow and peripheral blood erythroid progenitors to human recombinant erythropoietin (rHuEPO) was studied in nine haemodialysed renal failure patients receiving this hormone for the correction of their anaemia. The haematocrit rose in all patients in response to thrice weekly injections of escalating rHuEPO doses (12-192 IU/kg). Both the numbers of CUF-e and BFU-e and their proliferative state in the bone marrow as well as BFU-e numbers in the peripheral blood were estimated before treatment and again after correction of the anaemia, at 16 h following an intravenous dose of rHuEPO. Following treatment bone marrow BFU-e numbers fell to a mean of 24.5% (P less than 0.01) of the pre-treatment values although there was no significant change in CFU-e or circulating BFU-e numbers. The mitotic rate (percentage S-phase cells) estimated by tritiated thymidine suicide rose from 45.2% to 68.4% (P less than 0.05) in the case of CFU-e and from 16.4% to 45.1% (P less than 0.05) for BFU-e following treatment with rHuEPO thus indicating in-vivo sensitivity of both the primitive as well as the mature erythroid progenitors to the hormone. The fall in BFU-e numbers in the bone marrow after several months of treatment may be due to a loss of cells from this progenitor pool by maturation that is uncompensated by replacement from the pluripotential stem cell compartment.

Between February 1981 and December 1984 we treated 52 patients with chronic myeloid leukemia in the chronic phase and 18 patients with more advanced disease by high-dose chemoradiotherapy followed by allogeneic bone marrow transplantation using marrow cells from HLA-identical sibling donors. In addition, the 40 patients who had not previously undergone splenectomy received radiotherapy to the spleen. To prevent graft versus host disease, cyclosporine was given either alone or in conjunction with donor marrow depleted of T cells. Of the 52 patients treated in the chronic phase, 38 are alive after a median follow-up of 25 months (range, 7 to 50); the actuarial survival at two years was 72 percent, and the actuarial risk of relapse was 7 percent. Of the 18 patients with more advanced disease, 4 have survived; the actuarial two-year survival was 18 percent, and the actuarial risk of relapse was 42 percent. We conclude that the probability of cure is highest if transplantation is performed while the patient remains in the chronic phase of chronic myeloid leukemia. T-cell depletion may have reduced the incidence and severity of graft versus host disease. The value of irradiation to the spleen before transplantation has not been established.

Clonal assays for erythroid progenitors (BFU-e and CFU-e) were used to study 20 patients with rheumatoid arthritis, 15 of whom had anaemia of chronic disease and five of whom were haematologically normal. The numbers of bone marrow BFU-e and CFU-e in the anaemic patients did not differ significantly from those in normal controls. Macrophages were removed from the bone marrow by a combination of adherence and buoyant density centrifugation over a sucrose gradient and the resulting fractions were cultured alone or together with autologous adherent cells in BFU-e assays. Co-culture with adherent cells significantly increased colony growth in both the controls and in seven of eight anaemic patients studied. Serum from 14 anaemic patients and from five non-anaemic patients was added to cultures of bone marrow or to control peripheral blood 'null' cells. Anaemic serum uniformly either inhibited or failed to stimulate BFU-e growth under these conditions. Serum from non-anaemic patients and from 10 healthy controls stimulated BFU-e growth from 'null' cells to an equal degree.

The morphology of stained preparations of cells from human bone marrow and peripheral blood erythroid colonies cultured in methylcellulose, were examined by light microscopy. Although the morphology of 7 d erythroid colonies (CFU-E) was largely normoblastic, bone marrow and peripheral blood erythroid burst (BFU-E) showed a variable degree of megaloblastic and culture system and the deoxyuridine suppression test demonstrated active thymidine synthesis. Megaloblastic morphology was correlated with the growth induced by the addition of monocytes to erythroid progenitors. It was concluded that megaloblastosis was a feature of the erythroblasts derived from an early BFU-E which required monocytes for their development.

A one-stage flap repair is described for complicated dorsal injuries of the hand involving loss of skin and tendon based on the principle of the "Chinese" radial artery forearm flap in which vascularised tendons are transferred to reconstruct the missing extensor tendons.

Ranitidine was added in various concentrations (25-1600 ng/ml) to clonal assays of haemopoietic progenitors of normal human peripheral blood or bone marrow. Although a significant reduction in colonies forming from granulocyte-macrophage progenitors (CFU-GM) was demonstrated at the lowest drug concentration, no significant growth suppression was seen at higher concentrations. There was no evidence for growth inhibition of either erythroid progenitors (BFU-E) or pluripotent progenitors (CFU-mix) at any of the drug concentrations studied. A direct toxic effect of ranitidine on normal haemopoietic progenitors thus appears an unlikely cause of cytopenias observed during treatment.

The myeloproliferative disorders, including polycythaemia rubra vera, arise as a result of a single-cell mutation. A characteristic of the abnormal haemopoietic clone is that it can form erythroid colonies in vitro in the absence of added erythropoietin. Such endogenous erythroid clones were consistently found in two of seven patients with peripheral vascular disease. These two patients had mean platelet counts of 600 X 10(9)/l and 630 X 10(9)/l. Culture of blood and bone-marrow cells from patients with raised platelet counts secondary to a variety of other disorders failed to yield such colonies. The presence of endogenous erythroid clones provides early evidence of a myeloproliferative disorder.

An inappropriate response of the bone marrow is implicated in the aetiology of the anaemia of chronic disease complicating rheumatoid arthritis. T lymphocyte subsets have been shown to inhibit early erythroid development in vitro in association with some cases of bone marrow failure, and an expanded peripheral blood pool of these cells is reported in rheumatoid arthritis. We have studied the role of peripheral blood T lymphocytes in erythroid bone marrow culture from seven normal volunteers and nine anaemic patients with rheumatoid arthritis and found comparable stimulation of growth in both groups.

The growth in culture of circulating erythroid progenitors (BFU-e) from 34 patients with erythrocytosis was evaluated together with the clinical and bone marrow features at presentation and the subsequent response to treatment. Clonal erythroid growth in vitro in the absence of added erythropoietin (EEC) was observed in 17/18 patients with clinically unequivocal polycythaemia vera and in these patients bone marrow morphology was also abnormal. EEC were also present in three out of five patients with only a single minor criterion of that disease but none of the 11 patients without major or minor criteria or evidence of secondary polycythaemia were EEC positive. This group had a very low incidence of bone marrow abnormalities, was probably heterogenous in nature and included two patients with elevated serum immunoreactive erythropoietin of unknown cause. The reduction in haematocrit following treatment was assessed in EEC positive and negative patients and was found to be inferior in those lacking EEC. Thus both the poor therapeutic response and the low incidence of bone marrow abnormalities in patients lacking any other clinical features of polycythaemia vera correlated closely with the absence of EEC in in vitro culture. Myeloproliferative disorder may therefore be an unlikely cause of the erythrocytosis in such individuals.

A synomone present in hexane extracts of corn silks was found to attractOrius insidiosus (Say). The attraction was a diurnal, innate behavior, independant of sex. A portion of the prey-searching behavior ofO. insidiosus apparently relies on olfactory perception when corn is the prey's host.

Studies were directed to characterization of the anaemia of renal failure of 11 patients on haemodialysis and determination of the way in which it is corrected by human erythropoietin derived from recombinant DNA expressed in Chinese hamster ovary cells (r-HuEPO) administered intravenously. Erythrokinetics before treatment showed that total red cell mass was below normal and that both erythron transferrin uptake and red cell survival were modestly reduced; treatment increased both total red cell mass and erythron transferrin uptake but did not change red cell survival in previously untransfused patients. When BFU-e and CFU-e from patient bone marrow were cultured in autologous serum we found no evidence for inhibitors of erythroid progenitor maturation in patient serum compared with normal. Erythroid expansion in response to r-HuEPO was not limited by the availability of iron, iron requirements for new red cell formation being met from stores (if adequate) or from oral iron supplements. In pharmacokinetic studies the plasma clearance of r-HuEPO could be expressed by a three-parameter exponential curve with T1/2 range of 2.3 to 7.3 h. T1/2 after the first dose of r-HuEPO was not significantly different from that after 14 to 54 weeks treatment when the erythron had expanded to a new steady state. Erythron transferrin uptake before treatment was related to endogenous production of erythropoietin estimated from the plasma clearance of the first dose of r-HuEPO administered intravenously. This finding suggested that the availability of erythropoietin was the main factor limiting expansion of the erythron. This conclusion was supported by the continuity of the relationship during the response to treatment.

A retrospective questionnaire study, by post, revealed that 69% of patients, still living following first tumour recurrence, had detected the recurrence themselves prior to routine clinic appointments. Nearly 90% developed their first recurrence in the first 5 years following primary surgical treatment. Not only could the length of routine clinic follow-up after primary melanoma treatment be shortened, but with further education of the patient and involvement of the general practitioner it seems likely that patients can be trusted to detect their own recurrences and seek appropriate advice.

Globin chain synthesis was studied in mature erythroid bursts cultured from the peripheral blood null cells of 21 normal individuals. Although coculture of autologous T-lymphocytes with null cells resulted in a fivefold increase in the yield of erythroid bursts, the proportion of gamma chains synthesized (gamma/gamma + beta) was not significantly different from that seen without T cells. Coculture with autologous monocytes also resulted in increased burst-forming unit (BFU-e) proliferation but the ratio gamma/gamma + beta (0.25 +/- 0.03) was significantly higher than that seen with null cells alone (0.08 +/- 0.006) or with T cells (0.10 +/- 0.008). The relative increase in gamma-chain synthesis correlated with the severity of megaloblastic changes in erythroid progeny of BFU-e (P less than 0.01) but showed no significant relationship to the extent of colony maturation assessed by erythroblast maturity.

Colony assays in methylcellulose of primitive erythroid precursors (BFU-E) were carried out from the null cell fraction of normal human peripheral blood lymphoid cells. There was little proliferation or maturation of BFU-E as assessed by both the number and the size of colonies formed, when null cells alone were cultured. Culture of null cells with up to 8 X 10(5) autologous T-lymphocytes per ml led to considerable stimulation of colony growth and maturation. Culture of null cells with peripheral blood monocytes also resulted in the indication of BFU-E growth, although the response was inferior to the seen with T-cells. Co-culture of null cells together with both T-cells and monocytes resulted in a uniformly greater response than with either alone, and this was shown to be due to a positive interaction between these two cell types.

"Tadpole flaps" have been used in a series of 13 cleft palate patients in attempts to close anterior palatal fistulae over a 5-year period. The technique was successful in eight patients whose fistulae remained closed. The failures are discussed in detail.

Peripheral blood levels of BFU-e, CFU-GM and CFU-mix were studied serially in nine patients with acute leukaemia in remission during the period of recovery that followed induction or consolidation chemotherapy. Following 23 courses of treatment in the nine patients, the values for all three classes of progenitor were found to be higher in ALL than in AML (mean peak CFU-GM levels 5.8 x 10(3)/ml and 0.8 x 10(3)/ml respectively) and the highest levels were observed in patients recovering the most rapidly from bone marrow aplasia. Peak levels of these progenitors correlated best with the rate and extent of platelet recovery and all patients achieving blood levels of greater than 1.0 x 10(3) CFU-GM/ml had recovered greater than 100 x 10(9)/l platelets by 20 d and had peak platelet counts of greater than 400 x 10(9)/l within 40 d following chemotherapy. The peak values for circulating progenitors fell markedly after repeated courses of treatment in three of the five AML patients studied and this is likely to limit useful harvesting of such cells during later consolidation courses in this disease.

The precise vascular territory and the variations of the acromio-thoracic axis were investigated in a series of 60 fresh cadavers and 50 formalin fixed specimens using dissection, ink injection and barium radiographic studies. The sternocostal portion and the clavicular head of the pectoralis major were found to have virtually independent vascular and nerve supplies. The pectoral artery supplied the former, whereas the deltoid artery nourished the latter. The dominant supply from the pectoral artery to the rib cage was found to enter around the fourth rib in the mid clavicular line. This supply is associated with a previously undescribed origin of the pectoralis major muscle in this region. The supply to the sternum was determined as indirect via the captured territory of the internal mammary system. The dominant supply to the skin from the pectoral artery arose laterally along the free lower border of the muscle as fasciocutaneous branches. The deltoid artery supplies the skin over the shoulder by numerous small branches which emerge from the intramuscular septa of the deltoid muscle. In addition a large axial artery was noted. In most cases this arose from the deltoid artery or its acromial branch and coursed laterally. It is noteworthy that the majority of skin paddles of the pectoralis major myocutaneous flap currently used in clinical practice are designed medially and inferiorly around the perimeter of the muscle and onto the rectus sheath. In these situations such flaps are not supplied directly by the pectoral artery. In fact, they are supplied indirectly by cutaneous branches belonging to the internal mammary/superior epigastric system which are captured by arterial connections with the pectoral artery. These occur predominantly in the pectoralis major muscle. Suggestions, based on these anatomical studies, are offered to improve the versatility and safety of flaps designed in this area.

The myeloproliferative disorders are the result of an underlying abnormality of the pluripotential stem cell. One feature of this abnormality is a greatly increased sensitivity of the committed erythroid progenitors (BFU-E and CFU-E) to the hormone erythropoietin. Culture in vitro of these bone marrow or peripheral blood cells results in the growth of a proportion of colonies in the absence of added erythropoietin. These endogenous erythroid colonies (EEC) are seen in the great majority of cases of polycythaemia vera, as well as in some cases of thrombocythaemia, chronic myeloid leukaemia and idiopathic myelofibrosis. The presence of EEC appears to be a marker for the stem cell mutation and may serve to distinguish the neoplastic disorders from reactive increases of red cell mass or platelet numbers. Their absence in idiopathic erythrocytosis may also distinguish this condition from early polycythaemia vera and be useful in deciding on appropriate treatment. In patients with even a modest increase in the platelet count endogenous colonies provide firm evidence for a myeloproliferative disorder. Provision of myelosuppressive treatment can avert or improve vaso-occlusive or haemorrhagic complications. The mechanism of erythropoietin hypersensitivity is unknown but it has been shown to be a feature acquired rather late in maturation and by only a proportion of the progeny of the mutated clone. Normal erythroid progenitors co-exist with these abnormal cells in polycythaemia vera and the way in which their growth in vivo is inhibited has yet to be determined.