Post-traumatic triggering of extensor pollicis longus at the dorsal radial tubercle

A case of post-traumatic triggering of the tendon of extensor pollicis longus around Lister's tubercle is described. This condition was successfully treated by surgical release.

Methods for separation and deglycosylation of mucin subunits

Mucins (density 1.35-1.50 g/ml) prepared from human cervical, gastric, respiratory, and salivary secretions were reduced and alkylated to generate reduced mucin subunits. These subunits were separated into different populations analytically by using agarose gel electrophoresis and preparatively by using anion-exchange chromatography. Both techniques separate the molecules primarily on the basis of their inherent charge. A procedure has been developed for the efficient deglycosylation of small amounts of these reduced mucin subunits immobilized on polyvinylidene difluoride. The combination of these procedures has allowed the isolation and identification of glycoforms of a specific mucin gene product in a respiratory mucous secretion.

CD38 unresponsiveness of xid B cells implicates Bruton's tyrosine kinase (btk) as a regular of CD38 induced signal transduction

CD38 is a 42 kDa membrane-associated ectoenzyme expressed by a large proportion of human and mouse lymphocytes. Agonistic antibodies to CD38 induce a strong proliferative response in lymphocytes additionally co-stimulated with other growth co-factors such as IL-4, IL-2 plus accessory cells or sub-mitogenic doses of endotoxin. We show here that B lymphocytes from unstimulated X-linked immunodeficient (xid) mice are unresponsive to CD38 stimulation, both in terms of proliferative response and surface antigen modulation. This CD38 unresponsiveness is evident in the presence of excess quantities of, and normal responses to, the accessory growth co-stimulants required for this response. CD38 molecules expressed on xid B cells are normal in terms of expression levels, size and enzymatic activity, suggesting that CD38 unresponsiveness reflects a down-stream signaling defect. In light of the recent proposal that the xid gene encodes a tyrosine kinase called Bruton's tyrosine kinase (btk), these data suggest that btk is either an integral component or an indirect regulator of the CD38-induced signal transduction pathway.

Gut permeability measured by polyethylene glycol absorption in abnormal gut fermentation as compared with food intolerance

Gut permeability has been studied in patients with either food intolerance or abnormal gut fermentation as well as in normal subjects. Permeability was measured by polyethylene glycol absorption, and the reasons for this choice of probe are discussed. Results show that both symptomatic groups have statistically very highly significant deviations from the normal (P < 0.01), consisting of over-adsorption, significant at molecular weights 242, 286, 330 and 374. Whilst both study groups were different from the normal they were not different from each other. The implications for these findings in the diagnosis and management of food intolerance and abnormal gut fermentation are discussed.

Asymmetric arc technique for posterior pharyngeal wall and retropharyngeal space tumors

PURPOSE

Tumors of the posterior pharyngeal wall and nasopharyngeal cancer with retropharyngeal extension can partly encircle the cervical vertebrae. Treating the patient within spinal cord tolerance can cause a geographic miss. A simple technique has been developed to avoid this problem.

METHODS AND MATERIALS

The standard fields for posterior pharyngeal wall and nasopharyngeal tumors are used up to 36-40 Gy. A planning computed tomography (CT) scan is taken during the second or third week of treatment with the patient fitted in a new shell ensuring that the cord is straight and parallel to the treatment couch. The asymmetric arc technique consists of two posterior arcs with closure of one jaw beyond the central axis. Each arc delivers the total dose to each ipsilateral side, while the median region of the U-shaped volume is treated by the summation of both arcs.

RESULTS

We have treated 10 patients using asymmetric arcs in the last 3 years. This technique proved to be a versatile way of treating targets wrapped around the spine. The technique allows better individualization for target volume irregularities than the partial rotation with a central bar.

Association of protein kinase A and protein phosphatase 2B with a common anchoring protein

Specificity of protein kinases and phosphatases may be achieved through compartmentalization with preferred substrates. In neurons, adenosine 3', 5'-monophosphate (cAMP)-dependent protein kinase (PKA) is localized at postsynaptic densities by association of its regulatory subunit with an A kinase anchor protein, AKAP79. Interaction cloning experiments demonstrated that AKAP79 also binds protein phosphatase 2B, or calcineurin (CaN). A ternary complex of PKA, AKAP, and CaN was isolated from bovine brain, and colocalization of the kinase and the phosphatase was established in neurites of cultured hippocampal neurons. The putative CaN-binding domain of AKAP79 is similar to that of the immunophilin FKBP-12, and AKAP79 inhibited CaN phosphatase activity. These results suggest that both PKA and CaN are targeted to subcellular sites by association with a common anchor protein and thereby regulate the phosphorylation state of key neuronal substrates.

Cationic lipids for reporter gene and CFTR transfer to rat pulmonary epithelium

Increasing evidence indicates that cationic liposomes are capable of safely transferring foreign genes to pulmonary epithelium in vitro and in vivo. To transfer reporter genes and the cystic fibrosis transmembrane conductance regulator (CFTR) to mammalian respiratory epithelium we used two cationic lipid formulations: N-[1-(2,3-dioleoyloxy)propyl] N,N,N-triethylammonium chloride (DOTMA), and 1,2-dimyristyloxy-propyl-3-dimethylhydroxyethylammonium bromide (DMRIE) at a 1:1 molar ratio with dioleoyl phosphatidylethanolamine (DOPE). Lipid-DNA conjugates containing either CFTR or LacZ were instilled directly into the airways of Sprague-Dawley rats. Rats treated with LacZ cDNA in vivo demonstrated expression in 30-50% of the large and medium-sized airways, with some airways showing high efficiency gene transfer and expression (in the most proximal airways, 70-80% of surface epithelial cells were positive for expression of a nuclear targeted LacZ). While control and LacZ treated tracheas mounted in Ussing chambers showed minimal stimulation of transepithelial chloride (Cl)-currents by cAMP (suggesting low levels of endogenous rat CFTR activity), tracheas taken from animals receiving CFTR exhibited significant forskolin-stimulated currents at 72 h after gene transfer. Human CFTR gene expression was also detected by polymerase chain reaction (PCR) analysis of reverse transcribed lung RNA. These results, together with previous studies using lipid-mediated gene transfer in mice, help confirm the potential for cationic lipid-mediated gene transfer in the gene therapy of cystic fibrosis in humans.

An IFN-gamma-dependent pathway plays a critical role in the pathogenesis of murine immunodeficiency syndrome induced by LP-BM5 murine leukemia virus

The murine acquired immunodeficiency syndrome (MAIDS) caused by a defective murine leukemia virus produces severe immunodeficiency with abnormal lymphoproliferation and hypergammaglobulinemia. The presence of both CD4+ T cells and B cells is critical for the development of this disease. Remarkably elevated mRNA expression for IFN-gamma and IL-10 was observed in spleen cells of C57BL/6 mice starting from the early phase of viral infection. IFN-gamma production was induced by spleen cells from virus-infected mice upon stimulation with concanavalin A or lipopolysaccharide in both the early and late phases of MAIDS progression. When mice that had been passively administered anti-IFN-gamma mAb were infected with the virus, the development and progression of lymphadenopathy, immunodeficiency and elevated levels of serum IgG2a associated with MAIDS were delayed. Treatment with anti-IL-4 or anti-IL-10 mAb in place of anti-IFN-gamma mAb did not induce the delayed progression of MAIDS. These data support the concept that IFN-gamma-dependent pathway may be involved in the development of MAIDS.

Initiation of DNA synthesis by nuclei from scrape-ruptured quiescent mammalian cells in high-speed supernatants of Xenopus egg extracts

Demembranated sperm heads, detergent-isolated somatic nuclei and even naked DNA are efficiently replicated in cytoplasmic extracts of activated amphibian eggs, but only after nuclear assembly and the formation of an intact nuclear envelope. DNA synthesis has not previously been shown to be initiated in high-speed (200,000 g) supernatants of egg cytoplasm because they are depleted of the vesicular material required to support nuclear envelope formation. Here we show that mammalian nuclei prepared by scrape-rupture are able to initiate DNA replication in such high-speed supernatants. These nuclei begin DNA synthesis asynchronously. This asynchrony cannot be attributed to differences in the time taken for nuclear assembly. Instead, we suggest that the asynchrony reflects intrinsic differences between nuclei and that these differences are a major cause of cell cycle variability. Our demonstration of initiation in high-speed supernatants now enables the initiation of eukaryotic DNA synthesis to be studied independently of nuclear assembly.

Identification of two major populations of mucins in respiratory secretions

Two populations of reduced subunits were present in the mucins purified from pooled normal secretions and asthmatic and chronic bronchitic sputa; their relative level differed between samples. To investigate the nature of this heterogeneity, an asthmatic respiratory mucin preparation from a single individual was reduced and alkylated with 14C-iodoacetamide. This preparation was analyzed by gel filtration, agarose gel electrophoresis, immunoblotting, rate-zonal- and density-gradient centrifugation, and HPLC ion-exchange- and reverse-phase chromatography. Two populations (A and B) of reduced mucin subunits and a high-M(r)protein-rich fraction were identified. Species A has the higher molecular mass, is slowest migrating on agarose electrophoresis, has longer oligosaccharide chains, and expresses the carbohydrate structure sialyl-Le(x). Species B has a lower molecular mass, migrates faster in agarose electrophoresis Species B has a lower molecular mass, migrates faster in agarose electrophoresis, has shorter chains, and does not express sialyl-Le(x). The two subunits have similar but not identical amino acid compositions and 14C-tryptic peptide maps indicating they have different protein cores. The anti-sialyl-Le(x) antibody selectively precipitated subunit A not only from the reduced but also from the nonreduced mucin preparation, demonstrating that subunits A and B are present in different intact mucins.

Antibodies to murine CD40 protect normal and malignant B cells from induced growth arrest

We have previously described the production of polyclonal anti-murine CD40 antibodies that specifically bind recombinant murine CD40 expressed on L cells and induce vigorous proliferation of normal murine B lymphocytes. The current study utilizes these antibodies to explore the distribution and function of CD40 in murine B cell development. Murine CD40 is expressed at high levels by normal splenic B cells and all Ig-positive B cell lymphomas tested to date. It is not expressed by the 70Z/3 pre-B cell line, BaF3 pre-B cell line, or by numerous T cell and myeloid cell lines. 70Z/3 pre-B cells can be induced to express CD40 by LPS stimulation of the cells. Stimulation of purified splenic B cells with anti-CD40 antibodies causes upregulation of class II MHC antigens, CD23, and ICAM-1 and results in extensive aggregation of the cells. Antibodies to murine CD40 are extremely effective at rescuing malignant and normal B cells from induced growth arrest. Anti-CD40 antibodies protect WEHI-231 and CH31 B lymphoma cells from growth arrest induced by soluble anti-IgM antibodies, TGF beta, or a combination of both stimulants. Similarly, anti-IgM preactivated normal splenic B cells which normally die rapidly from growth arrest after 1 or 2 days culture produce a vigorous proliferative response to subsequent stimulation with anti-CD40 antibodies plus IL-4. Interestingly, anti-CD40 antibodies provide little to no protection against B lymphoma growth arrest induced by immobilized anti-IgM antibodies. These data confirm and extend functional properties assigned previously to human CD40 and identify numerous defined murine model systems to explore the molecular basis of CD40-mediated protection from induced B cell growth arrest.

Improving trauma care in Trinidad and Tobago

Identification of trauma as a major cause of morbidity and mortality in Trinidad and Tobago prompted the establishment of a training programme aimed at improving trauma care in this developing country. An Advanced Trauma Life Support (ATLS) programme for physicians, funded through the Canadian International Development Agency resulted in a statistically significant improvement of in-hospital trauma patient outcome at the Port-of-Spain General Hospital (observed to expected mortality ratio of 3.16 pre-ATLS compared to 1.94 post-ATLS). A recent analysis of all motor vehicle injuries for a shorter period did not confirm this positive impact of the ATLS programme, primarily because a large number of these patients died in the pre-hospital period. Pre-hospital trauma care therefore required urgent attention to complement the positive in-hospital impact of the ATLS programme. A second training programme (the Pre-Hospital Trauma Life Support or PHTLS) for paramedical personnel was thus instituted in 1990. Over 250 physicians have been trained in the ATLS programme and to date over 100 paramedical personnel have been trained in the PHTLS programme. Attempts have also been made to equip the ambulances with more appropriate resuscitative devices in order to improve pre-hospital care. The combination of the PHTLS and the ATLS programme should result in further improvement in the care of patients sustaining major injuries in Trinidad and Tobago.

Cognitive and attitudinal impact of the Advanced Trauma Life Support program in a developing country

Improvement in trauma patient outcome has been reported after Advanced Training Life Support training (ATLS) in the developing country of Trinidad and Tobago (T & T). The cognitive impact of ATLS training was assessed from pre-ATLS and post-ATLS performance of T & T physicians in multiple choice question tests and comparison with post-ATLS test performance among Nebraska physicians. Overall, improvement between the pre-test and post-test among the T & T physicians was 22.0% +/- 2.0%. All physicians including failures (199 out of 212 passed) improved in their post-test scores. Individual item analysis of the post-test, including the KR-20 determination, varied but the overall performance was similar for both physician groups with the T & T physicians performing slightly better in test 2 (6 of 16 vs. 25 of 100 failures, p < 0.05). Attitudinal impact was assessed through 87 questionnaires from 50 physicians (92% response) and 37 nurses (89% response). Physicians (97.8% compared with 69.7%) were more aware of the ATLS training, and both groups (physicians, 77.3%; nurses, 69.6%) differentiated ATLS-trained physicians based on better resuscitation, more timely and appropriate consultation, greater confidence in trauma management, and improvement in trauma mortality and morbidity; all respondents recommended ATLS training for all emergency room physicians. The demonstrated positive cognitive and attitudinal effects very likely contributed to the improved post-ATLS trauma patient outcome.

Advanced trauma life support program increases emergency room application of trauma resuscitative procedures in a developing country

Over a 9-year period (July 1981-December 1985--pre-ATLS period; January 1986-June 1990--post-ATLS period), the hospital charts of 813 trauma patients with ISS > or = 16 were reviewed (n = 413, pre-ATLS and n = 400, post-ATLS) in order to assess the impact of the ATLS program. The frequency of endotracheal intubation (ET), nasogastric tube insertion (NG), intravenous access (i.v.), Foley catheterization of the bladder (Foley) and chest tube insertion (CT) were compared by Pearson Chi-square analysis. Overall, pre-ATLS vs. post-ATLS frequencies (%) were 83.5 vs. 65.3 for ET, 97.3 vs. 98.0 for i.v., 74.6 vs. 96.3 for Foley, 68.3 vs. 91.3 for NG, and 18.4 vs. 47.0 for CT. In the emergency room these frequencies (%) were 26.1 vs. 36.4 for ET, 98.8 vs. 98.7 for i.v., 11.0 vs. 97.1 for Foley, 3.2 vs. 95.9 for NG, and 3.9 vs. 95.2 for CT. The differences in the application of these life saving procedures between the pre-ATLS and post-ATLS periods were statistically significant (p < 0.05) except i.v. access, which showed no difference between the pre-ATLS and post-ATLS groups. Of the patients with severe chest injuries (AIS > or = 3) 87.7% had chest tubes post ATLS (94.4% in ER) compared with 48.1% pre ATLS (3.2% in ER). These differences were associated with significant improvement in trauma patient outcome post ATLS. We conclude that the frequency of lifesaving interventions, particularly in the ER, was increased post ATLS.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunoglobulin signal transduction guides the specificity of B cell-T cell interactions and is blocked in tolerant self-reactive B cells

The specificity of antibody (Ab) responses depends on focusing helper T (Th) lymphocyte signals to suitable B lymphocytes capable of binding foreign antigens (Ags), and away from nonspecific or self-reactive B cells. To investigate the molecular mechanisms that prevent the activation of self-reactive B lymphocytes, the activation requirements of B cells specific for the Ag hen egg lysozyme (HEL) obtained from immunoglobulin (Ig)-transgenic mice were compared with those of functionally tolerant B cells isolated from Ig-transgenic mice which also express soluble HEL. To eliminate the need for surface (s)Ig-mediated Ag uptake and presentation and allow the effects of sIg signaling to be studied in isolation, we assessed the ability of allogeneic T cells from bm12 strain mice to provide in vivo help to C57BL/6 strain-transgenic B cells. Interestingly, non-tolerant Ig-transgenic B cells required both allogeneic Th cells and binding of soluble HEL for efficient activation and Ab production. By contrast, tolerant self-reactive B cells from Ig/HEL double transgenic mice responded poorly to the same combination of allogeneic T cells and soluble HEL. The tolerant B cells were nevertheless normally responsive to stimulation with interleukin 4 and anti-CD40 Abs in vitro, suggesting that they retained the capacity to respond to mediators of T cell help. However, the tolerant B cells exhibited a proximal block in the sIg signaling pathway which prevented activation of receptor-associated tyrosine kinases in response to the binding of soluble HEL. The functional significance of this sIg signaling defect was confirmed by using a more potent membrane-bound form of HEL capable of triggering sIg signaling in tolerant B cells, which markedly restored their ability to collaborate with allogeneic Th cells and produce Ab. These findings indicate that Ag-specific B cells require two signals for mounting a T cell-dependent Ab response and identify regulation of sIg signaling as a mechanism for controlling self-reactive B cells.

Socio-economic causes and cultural explanations of childhood malnutrition among the Chagga of Tanzania

This study provides an in-depth analysis of the complexity of factors involved in selective child survival among the Chagga people of Mt Kilimanjaro, Tanzania. Carried out during the first of a series of post-independence economic crises, the study analyzes the impact of fluctuations in world economy, ecological stresses, demographic pressures, and class formation in creating conditions of poverty and lessening the ability of many Chagga to provide adequate care for their children. Qualitative and quantitative information are given from a follow-up study of families whose children were placed in a nutrition rehabilitation program during the drought of 1972-73. Four cases from that study further demonstrate the impact of macroeconomic forces on individuals and provide material for analyzing a complex pattern of cultural beliefs which made up part of the Chagga people's explanations for child malnutrition.

School-based programs to reduce sexual risk behaviors: a review of effectiveness

This review was undertaken in recognition of the mounting public health and social problems associated with adolescent sexual behavior and the importance of basing school-affiliated programs designed to reduce sexual risk-taking behavior on sound research. The authors were commissioned by the Division of Adolescent and School Health within the Centers for Disease Control and Prevention, Public Health Service, to review carefully the research on these programs and to assess their impact on behavior. The authors identified 23 studies of school-based programs that were published in professional journals and measured program impact on behavior. They then summarized the results of those studies, identifying the distinguishing characteristics of effective programs, and citing important research questions to be addressed in the future. Not all sex and AIDS education programs had significant effects on adolescent sexual risk-taking behavior, but specific programs did delay the initiation of intercourse, reduce the frequency of intercourse, reduce the number of sexual partners, or increase the use of condoms or other contraceptives. These effective programs have the potential to reduce exposure to unintended pregnancy and sexually transmitted disease, including HIV infection. These programs should be replicated widely in U.S. schools. Additional research is needed to improve the effectiveness of programs and to clarify the most important characteristics of effective programs.

Continuous administration of anti-interleukin 10 antibodies delays onset of autoimmunity in NZB/W F1 mice

We have previously shown that continuous administration of anti-interleukin 10 (anti-IL-10) antibodies (Abs) to BALB/c mice modifies endogenous levels of autoantibodies, tumor necrosis factor alpha (TNF-alpha), and interferon gamma, three immune mediators known to affect the development of autoimmunity in "lupus-prone" New Zealand black/white (NZB/W)F1 mice. To explore the consequences of IL-10 neutralization in NZB/W F1 mice, animals were injected two to three times per week from birth until 8-10 mo of age with anti-IL-10 Abs or with isotype control Abs. Anti-IL-10 treatment substantially delayed onset of autoimmunity in NZB/W F1 mice as monitored either by overall survival, or by development of proteinuria, glomerulonephritis, or autoantibodies. Survival at 9 mo was increased from 10 to 80% in anti-IL-10-treated mice relative to Ig isotype-treated controls. This protection against autoimmunity appeared to be due to an anti-IL-10-induced upregulation of endogenous TNF-alpha, since anti-IL-10-protected NZB/W F1 mice rapidly developed autoimmunity when neutralizing anti-TNF-alpha Abs were introduced at 30 wk along with the anti-IL-10 treatment. Consistent with the protective role of anti-IL-10 treatment in these experiments, continuous administration of IL-10 from 4 until 38 wk of age accelerated the onset of autoimmunity in NZB/W F1 mice. The same period of continuous IL-10 administration did not appear to be toxic to, or cause development of lupus-like autoimmunity in normal BALB/c mice. These data suggest that IL-10 antagonists may be beneficial in the treatment of human systemic lupus erythematosus.

Formation and hydrolysis of cyclic ADP-ribose catalyzed by lymphocyte antigen CD38

CD38 is a 42-kilodalton glycoprotein expressed extensively on B and T lymphocytes. CD38 exhibits a structural homology to Aplysia adenosine diphosphate (ADP)-ribosyl cyclase. This enzyme catalyzes the synthesis of cyclic ADP-ribose (cADPR), a metabolite of nicotinamide adenine dinucleotide (NAD+) with calcium-mobilizing activity. A complementary DNA encoding the extracellular domain of murine CD38 was constructed and expressed, and the resultant recombinant soluble CD38 was purified to homogeneity. Soluble CD38 catalyzed the formation and hydrolysis of cADPR when added to NAD+. Purified cADPR augmented the proliferative response of activated murine B cells, potentially implicating the enzymatic activity of CD38 in lymphocyte function.

Expression of the murine interleukin-4 gene in an attenuated aroA strain of Salmonella typhimurium: persistence and immune response in BALB/c mice and susceptibility to macrophage killing

Cytokines are potentially useful in vaccination as adjuvants or modulators of the type of response induced. The work below describes the expression of a cloned cytokine gene for murine interleukin-4 (mIL-4) by a live vaccine vector, an attenuated aroA strain (SL7207) of Salmonella typhimurium, in a murine model system. SL7207 was used as a carrier for two different high-level expression vectors. Both resulting strains, designated SL7207(pOmpAmIL-4) and SL7207(pKKmIL-4), expressed the cloned gene product as monitored by both immunological and biological assays. However, SL7207(pOmpAmIL-4) produced mIL-4 at higher levels and was more stable in vitro than SL7207(pKKmIL-4). When SL7207(pOmpAmIL-4) was used as a live vaccine in BALB/c mice, this strain grew and survived at higher levels than the parental attenuated strain or empty plasmid-carrying strain in spleens, livers, and intestines. This difference in growth and survival did not appear to be caused by alterations in specific lymphocyte-mediated anti-Salmonella immune responses such as delayed-type hypersensitivity or serum antibody as measured by enzyme-linked immunosorbent assay; such alterations have been induced by IL-4 administration in other in vivo systems, and the lack of effect here may reflect the fact that IL-4 is not secreted from the bacteria in large quantities, most of the cytokine being in the cytoplasmic-membrane-bound fraction. Conversely, the ability of mouse macrophages to kill the bacteria in vitro was inhibited by bacterial production of mIL-4. This reduction in macrophage killing activity suggests that bacterial production of mIL-4 may be detrimental to host defense against Salmonella infection and may explain the enhanced bacterial growth and survival in vivo.

Prospective evaluation of unrelated donor bone marrow transplantation. The International Marrow Unrelated Search and Transplant (IMUST) Study

The International Marrow Unrelated Search and Transplant (IMUST) Study has prospectively assessed outcome of unrelated donor BMT (UD-BMT) in comparison with a matched cohort of patients treated by HLA-identical sibling BMT (ID-BMT). We report an interim analysis of the first 165 UD-BMT and 368 ID-BMT. Eighty-two percent of UD-BMT pairs were matched by serology for HLA-A, B and DR, 10% were less well matched and HLA matching data was incomplete in 8%. The Kaplan-Meier estimated probability of survival until day 400 was 0.42 (95% confidence limits 0.33-0.51) after UD-BMT and 0.62 (0.56-0.68) after ID-BMT (p = < 0.001). Probability of engraftment by day 100 was 0.90 (0.85-0.95) and 0.95-0.99) after UD-BMT and ID-BMT, respectively (p = < 0.001). Cumulative probability of acute GVHD by day 100 was 0.52 (0.45-0.60) and 0.42 (0.37-0.47) after UD-BMT and ID-BMT, respectively (p = 0.009). After UD-BMT, 52% of patients with early disease survived until day 400 (40-64%) and 27% (14-40%) with advanced disease (p = < 0.001). Multifactorial analysis of survival showed success was related to the centre's experience of UD-BMT and this effect was modified by conditioning protocol. Increased probability of survival after UD-BMT in centres with most experience of the procedure is novel finding. We conclude UD-BMT is a more difficult procedure than ID-BMT but results are acceptable in patients with early disease and when UD-BMT is carried out in experienced centres.