Stem cell factor retards differentiation of normal human erythroid progenitor cells while stimulating proliferation

Stem cell factor (SCF), the ligand for the c-kit tyrosine kinase receptor, markedly stimulates the accumulation of erythroid progenitor cells in vitro. We now report that SCF delays erythroid differentiation among the progeny of individual erythroid progenitors while greatly increasing the proliferation of these progeny. These effects appear to be independent of an effect on maintenance of cell viability. Highly purified day-6 erythroid colony-forming cells (ECFC), consisting mainly of colony-forming units-erythroid (CFU-E), were generated from human peripheral blood burst-forming units-erythroid (BFU-E). Addition of SCF to the ECFC in serum-free liquid culture, together with erythropoietin (EP) and insulin-like growth factor 1 (IGF-1), resulted in a marked increase in DNA synthesis, associated with a delayed peak in cellular benzidine positivity and a delayed incorporation of 59Fe into hemoglobin compared with cultures without SCF. In the presence of SCF, the number of ECFC was greatly expanded during this culture period, and total production of benzidine-positive cells plus hemoglobin synthesis were ultimately increased. To determine the effect of SCF on individual ECFC, single-cell cultures were performed in both semisolid and liquid media. These cultures demonstrated that SCF, in the presence of EP and IGF-1, acted on single cells and their descendants to delay erythroid differentiation while substantially stimulating cellular proliferation, without an enhancement of viability of the initial cells. This was also evident when the effect of SCF was determined using clones of ECFC derived from single BFU-E. Our experiments demonstrate that SCF acts on individual day-6 ECFC to retard erythroid differentiation while simultaneously providing enhanced proliferation by a process apparently independent of an effect on cell viability or programmed cell death.     

Ovine forestomach matrix biomaterial is a broad spectrum inhibitor of matrix metalloproteinases and neutrophil elastase

Proteases play a critical role in the ordered remodelling of extracellular matrix (ECM) components during wound healing and tissue regeneration. However, the usually ordered proteolysis is compromised in chronic wounds due to over‐expression and high concentrations of matrix metalloproteinase's (MMPs) and neutrophil elastase (NE). Ovine forestomach matrix (OFM) is a decellularised extracellular matrix‐based biomaterial developed for tissue regeneration applications, including the treatment of chronic wounds, and is a heterogeneous mixture of ECM proteins and proteoglycans that retains the native structural and functional characteristics of tissue ECM. Given the diverse molecular species present in OFM, we hypothesised that OFM may contain components or fragments that inhibit MMP and NE activity. An extract of OFM was shown to be a potent inhibitor of a range of tissue MMPs (IC₅₀s = 23 ± 5 to 115 ± 14 µg/ml) and NE (IC₅₀ = 157 ± 37 µg/ml), and was more potent than extracts prepared from a known protease modulating wound dressing. The broad spectrum activity of OFM against different classes of MMPs (i.e. collagenases, gelatinases and stromelysins) may provide a clinical advantage by more effectively addressing the protease imbalance seen in chronic wounds.     

Capillary transit time heterogeneity and flow-metabolism coupling after traumatic brain injury

Most patients who die after traumatic brain injury (TBI) show evidence of ischemic brain damage. Nevertheless, it has proven difficult to demonstrate cerebral ischemia in TBI patients. After TBI, both global and localized changes in cerebral blood flow (CBF) are observed, depending on the extent of diffuse brain swelling and the size and location of contusions and hematoma. These changes vary considerably over time, with most TBI patients showing reduced CBF during the first 12 hours after injury, then hyperperfusion, and in some patients vasospasms before CBF eventually normalizes. This apparent neurovascular uncoupling has been ascribed to mitochondrial dysfunction, hindered oxygen diffusion into tissue, or microthrombosis. Capillary compression by astrocytic endfeet swelling is observed in biopsies acquired from TBI patients. In animal models, elevated intracranial pressure compresses capillaries, causing redistribution of capillary flows into patterns argued to cause functional shunting of oxygenated blood through the capillary bed. We used a biophysical model of oxygen transport in tissue to examine how capillary flow disturbances may contribute to the profound changes in CBF after TBI. The analysis suggests that elevated capillary transit time heterogeneity can cause critical reductions in oxygen availability in the absence of ‘classic'' ischemia. We discuss diagnostic and therapeutic consequences of these predictions.     

PROGNOSTIC SIGNIFICANCE OF THE CO-EXPRESSION OF p53 AND c-erbB-2 PROTEINS IN BREAST CANCER

The immunohistochemical expression of p53 and c-erbB-2 gene proteins was examined in a series of 130 breast adenocarcinomas. This study intended to investigate whether the frequency of the altered expression of the tumour suppressor gene p53 and the overexpression of the oncogene c-erbB-2 in breast cancer tissue cells correlated with other variables known to affect the biological behaviour of these tumours and the overall survival of the patients (median follow-up time: 6 years). The expression of p53 protein and c-erbB-2 gene product was evaluated immunohistochemically. Expression of p53 protein was detected in 30 (23 per cent) of the neoplasms examined, while 26 (20 per cent) out of the 130 cases demonstrated positive c-erbB-2 immunoreactivity. There was a statistically significant association between p53 protein expression and primary tumour size, lymph node involvement, and oestrogen receptor positivity. The incidence of c-erbB-2 positivity was significantly correlated with high tumour grade, axillary node invasion, large tumour size, and the absence of steroid receptors. p53 immuno-expression was clearly associated with c-erbB-2 protein overexpression. Concomitant p53 and c-erbB-2 positive immunolabelling, which emerged in 14 out of the 130 cases (10·7 per cent), was clearly associated with high grade, large size, positive nodal status, ductal infiltrating (NOS) histological type, and low values of progesterone receptors. Overall survival of patients was not significantly related to the immunoreactivity of either p53 or c-erbB-2 considered separately, whereas there was a clearly significant trend to worse overall prognosis in cancers with double p53/c-erbB-2 positive phenotype. The simultaneous immunodetection of p53/c-erbB-2 appears to have greater negative prognostic relevance than their separate expression.     

Second‐look endoscopy with thermal coagulation or injections for peptic ulcer bleeding: A meta‐analysis

Background and Aims: In the management of peptic ulcer bleeding, the benefits of second‐look endoscopic treatment with thermal coagulation or injections in controlling recurrent bleeding is unsure. This study set out to compare efficacy of routine second‐look endoscopy with treatment using either thermal coagulation or injections versus single endoscopy by pooling data from published work. Methods: Full publications in the English‐language published work as well as abstracts in major international conferences were searched over the past 10 years, and six trials fulfilling the search criteria were found. Outcome measurements included: (i) recurrent bleeding; (ii) requirement of surgical intervention; and (iii) mortality. We examined heterogeneity of trials and pooled the effects by meta‐analysis. The quality of studies was graded according to the prospective randomization, methods of patient allocation, the list of exclusion criteria, outcome definitions and the predefined salvage procedures for uncontrolled bleeding. Results: Among 998 patients recruited in these five randomized trials, 119 received routine second‐look endoscopy with thermal coagulation, and 374 received second‐look with endoscopic injection and 505 had single endoscopic therapy. Less recurrent bleeding was reported after thermal coagulation (4.2%) than single endoscopy (15.7%) (relative risk [RR] = 0.29; 95% confidence interval [CI] = 0.11–0.73), but no reduction was reported for the requirement of surgical intervention and all‐cause mortality. Injection therapy did not reduce re‐bleeding (17.6%) when compared to single endoscopy (20.8%; RR = 0.85; 95% CI = 0.63–1.14), requirement for surgery and mortality. Conclusion: Routine second‐look endoscopy with thermal coagulation, but not injection therapy, reduced recurrent peptic ulcer bleeding. There is no proven benefit in reducing surgical intervention and overall mortality.     

Anti-neutrophil cytoplasmic antibodies in Japanese children with ulcerative colitis

Objective: To investigate the diagnostic value of anti-neutrophil cytoplasmic antibodies (ANCA) in the diagnosis of ulcerative colitis (UC) in Japanese children.
Methodology Serum samples from 23 children with UC (17 Japanese, 6 non-Japanese), 27 children with Crohn's disease (CD) (10 Japanese, 17 non-Japanese), 10 children with other diarrhoeal diseases, and 33 normal, healthy adult volunteers were assayed for ANCA using an indirect immunofluorescence technique.
Results ANCA were detected in 6/17 (35%) UC patients and 0/10 (0%) CD patients in Japanese children, and in 3/6 (50%) UC patients and 3/17 (18%) CD patients in non-Japanese children. The difference in prevalence between Japanese and non-Japanese children with UC was not statistically significant ( P >0.05). ANCA were not found in other diarrhoeal patients and volunteers.
Conclusions Although ANCA have been reported to be useful in the diagnosis of UC in adults, they may be of limited use in Japanese children. This might reflect the heterogeneity of UC.     

Phage typing and PFGE pattern analysis as tools for epidemiological surveillance of Salmonella enterica serovar Bovismorbificans infections

Some years ago, an increase in the number of sporadic cases and outbreaks of salmonellosis due to S. enterica serovar Bovismorbificans was observed in several European countries including Finland, Sweden, England/Wales, Austria, and Germany. In order to understand the recent spread of this serovar and to trace the route of infection back to its source, it was considered necessary to subtype S. Bovismorbificans isolates. Using phage typing (newly described here) and molecular fingerprinting (PFGE-pattern, plasmid profiles and ribotype) the isolates of European origin could be subtyped and compared to S. Bovismorbificans isolates that originated in overseas countries such as Australia, Thailand, India, etc. where this serovar was isolated more frequently. Significant clonal diversity was identified but some of the clonal types of S. Bovismorbificans dominated the epidemics and single cases in Europe as well as in overseas countries. The clonal identity among these isolates indicates an international distribution, new sources of infection, and highlights the urgent requirement for standardized laboratory based surveillance networks (e.g. Enter-Net). Moreover, it is suggested that strains of S. Bovismorbificans will continue to be of concern in public health and that phage typing together with PFGE typing can be applied as reliable and rapid tools for their future monitoring.     

Elephantiasis nostras verrucosa: beneficial effect of oral etretinate therapy

Elephantiasis nostras verrucosa is characterized by chronic secondary, non-filarial lymphoedema due to recurrent lymphangitis, dermal fibrosis, and epidermal changes consisting of hyperkeratotic, verrucous and papillomatous lesions. Histologically, there is pseudoepitheliomatous hyperplasia. Therapeutic efforts should aim to reduce lymph stasis, which will also lead to improvement of the cutaneous changes. In this study, rapid disappearance of the hyperkeratotic and verrucous lesions, remarkable flattening of the papillomatous nodules and improvement of lymphoedema occurred in three obese patients treated with etretinate in an initial dose of 0.6-0.75 mg/kg/day for 4-6 weeks. Monitoring of plasma concentrations of etretinate, acitretin and 13-cis-acitretin by HPLC revealed sufficient short-time absorption (4 h) and bioavailability of the drug (30 days; two out of three patients). Long-term maintenance therapy in one patient produced a remarkable improvement in the lymphoedema; another patient relapsed after discontinuation of the etretinate and responded again after this was reintroduced. In the third patient treatment was withdrawn because of an increase in triglycerides, but improvement persisted 6 months later. The clinical side-effects of oral retinoid therapy were moderate and well tolerated.