Oral procainamide as pharmacological treatment of recurrent and refractory ventricular tachyarrhythmias

Funding Acknowledgements

Type of funding sources: None.

Background

The antiarrhythmic therapy of recurrent ventricular arrhythmias in patients having undergone catheter ablation and in whom amiodarone and/or beta blockers were ineffective or contraindicated, is a controversial issue.

Purpose

The present study sought to evaluate the efficacy and tolerability of oral procainamide in patients with recurrent ventricular arrhythmias, when the standard therapy strategy failed.

Methods

All patients with an implantable cardioverter defibrillator (ICD)  treated with oral procainamide for recurrent ventricular tachycardia (VT) or ventricular fibrillation (VF) in our institution between January 2010 and May 2019 were enrolled. The primary endpoint was the total number of ICD interventions after the beginning of procainamide therapy. Secondary endpoints were total number of VTs and VFs recorded on the ICDs controls, and discontinuation of therapy. The events occurring during procainamide treatment were compared with a matched duration period before the initiation of therapy with procainamide. Patients therefore served as self-controls.

Results

A total of 33 consecutive patients (31 males, 93.3%; mean age 73.3 ± 10 years) were included in the retrospective analysis. The mean time of procainamide treatment was 12.5 ± 13.5 months. The mean dose of procainamide was 1194 ± 495 mg/die. Procainamide therapy significantly decreased ICD interventions (DC shock: 102 vs 132; anti-tachycardia pacing: 418 vs 603; 12 patients manifested DC shock after the beginning of treatment vs 25 patients before treatment). Procainamide also decreased the total number of VT/VF episodes (514 vs 1078 episodes) [p < 0,01]. Only 2 patients (6%) presented severe side effects (hypothension) requiring discontinuation of therapy.

Conclusions

Procainamide was associated with a significant decrease of ICD therapies and ventricular arrhythmias showing an optimal profile of tolerability.

Anti-inflammatory activity of citrus pectin on chicken monocytes' immune response

Pectin is a dietary fibre composed of galacturonic acid, primarily found in the citrus fruits' cell walls. Citrus pectin (CP) has demonstrated antioxidative, anticancer, and anti-inflammatory properties in humans and animals. In broilers, CP supplementation improves energy utilization and nutrient digestibility, but limited information on its effects on chicken immunity is available so far. This study aimed to assess the in vitro impact of CP on chicken monocytes' immune response. Cells were purified from whole blood of healthy chickens and incubated with increasing concentrations (0, 0.25, 0.5, 0.75, 1 mg/mL) of CP to determine CP working concentration. The effects of different CP concentrations on cells' apoptosis and viability were assessed by measuring caspase-3 and -7 and the cells' metabolic activity (MTT assay), respectively. CP had no dose-dependent effect on monocyte apoptosis and viability.Then, the effects of CP (0.5 mg/mL) on chicken monocytes' chemotaxis and phagocytosis were assessed by measuring transwell migration and fluorescein-labelled E. coli incorporation, respectively. CP inhibited both monocytes' chemotaxis and phagocytosis.These data demonstrate that CP exerts an immunomodulatory role in chicken monocytes, supporting its integration in nutrition strategies that might be beneficial for the animal's immunity and health.

Rapid detection and quantification of plasmid-mediated colistin resistance genes (mcr-1 to mcr-5) by real-time PCR in bacterial and environmental samples

AIM

The aim of the study was to validate a rapid method to detect and quantify colistin resistance genes (mcr-1 to mcr-5) by real-time polymerase chain reaction (RT-PCR) in diverse matrices.

METHODS AND RESULTS

The detection limit of two newly designed SYBR Green real-time PCR assays for mcr-4 and mcr-5 and of previously published protocols for mcr-1 to mcr-3 was assessed using serial dilutions of reference strains. The assays could detect all five mcr genes with the lower limit of 10² copy numbers. Escherichia coli isolates (n = 1062) and environmental samples (n = 93) were tested for the presence of mcr genes. The assays enabled the detection of colistin resistance genes both in bacterial isolates and in complex environmental samples.

CONCLUSIONS

This method represents a set of sensitive, rapid and effective assays for the screening of colistin resistance directly from the environment.

SIGNIFICANCE AND IMPACT OF THE STUDY

Colistin is an antimicrobial commonly used in animals and has recently emerged as a last-resort treatment in humans. Plasmid-mediated mcr genes confer resistance to colistin and represent a major threat for public health since they can be easily disseminated through horizontal gene transfer. The rapid and sensitive detection of mcr genes is of utmost necessity.

Containing a measles outbreak in Minnesota, 2017: methods and challenges

AIMS

We report on a measles outbreak largely occurring in Minnesota's under-vaccinated Somali community in the spring of 2017. The outbreak was already into its third generation when the first two cases were confirmed, and rapid public health actions were needed. The aim of our response was to quickly end transmission and contain the outbreak.

METHODS

The state public health department performed laboratory testing on suspect cases and activated an Incident Command staffed by subject matter experts that was operational within 2 h of case confirmation. Epidemiologic interviews identified exposures in settings where risk of transmission was high, that is, healthcare, childcare, and school settings. Vaccination status of exposed persons was assessed, and postexposure prophylaxis (PEP) was offered, if applicable. Exposed persons who did not receive PEP were excluded from childcare centers or schools for 21 days. An accelerated statewide measles, mumps, and rubella (MMR) recommendation was made for Somali Minnesota children and children in affected outbreak counties. Partnerships with the Somali Minnesota community were deepened, building off outreach work done with the community since 2008.

RESULTS

Public health identified 75 measles cases from 30 March to 25 August 2017: 43% were female, 81% Somali Minnesotan, 91% unvaccinated, and 28% hospitalized. The median age of cases was 2 years (range: 3 months-57 years). Most transmission (78%) occurred in childcare centers and households. A secondary attack rate of 91% was calculated for unvaccinated household contacts. Over 51,000 doses of MMR were administered during the outbreak above expected baseline. At least 8490 individuals were exposed to measles; 155 individuals received PEP; and over 500 persons were excluded from childcare and school. State and key public health partners spent an estimated $2.3 million on response.

CONCLUSION

This outbreak demonstrates the necessity of immediate, targeted disease control actions and strong public health, healthcare, and community partnerships to end a measles outbreak.

At-vessel mortality of skates (Rajidae) taken in coastal fisheries and evidence of longer-term survival

Data on the vigour and at-vessel mortality (AVM) of 6798 skates (comprising Raja clavata n = 6295; R. brachyura n = 208; R. undulata n = 185, R. montagui n = 98 and R. microocellata n = 12) captured by commercial fishing vessels in the inshore waters of the southern North Sea and English Channel were recorded. AVM in longline fisheries averaged 0·44% across five vessels (0-1·47%), although skates were usually unhooked manually and did not usually pass through a bait-stripper. AVM in otter trawls averaged 0·76% (0-2·35%), from four vessels fishing with tow durations of <1·5 h (southern North Sea) or 1-4 h (English Channel). No AVM was noted for skates taken as a by-catch in drift trammel nets (soak times <4 h). Anchored tangle nets resulted in an overall AVM of 2·0-2·7%, but increased from 1·47% (13-28 h soak time) to 6·16% (42-53 h soak time). There were significant differences in the vigour of skates between gears, with R. clavata caught by longline and tangle nets in better condition than those captured by otter trawl or drift trammel net. Similarly, R. undulata caught by tangle net were in better condition than those caught by otter trawl. The vigour of R. undulata was also found to be higher than other skate species for both trawl and tangle net. In total, 5283 skates were tagged with Petersen discs and released, with recapture rates for the various combinations of vessel and gear ranging up to 24·8% for R. clavata. Whilst confirming a degree of post-release survival, quantitative estimates of post-release mortality for skates remain unknown.

Retraction notice to "Fungal diversity is negatively affected by habitat fragmentation: a meta-analysis" [Current Opinion in Microbiology 37 (2017) 61-66]

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article that has already been published in <Current Opinion in Microbiology, 37, June 2017 61-66>, http://dx.doi.org/10.1016/j.mib.2017.03.015 has been withdrawn at the request of the editor and publisher. The publisher regrets that an error occurred which led to the premature publication of this paper. This error bears no reflection on the article or its authors. The publisher apologizes to the authors and the readers for this unfortunate error.

Fungal diversity at fragmented landscapes: synthesis and future perspectives

Fungi are organisms with important roles in ecosystem functioning and services, but knowledge about how habitat fragmentation affect fungal diversity is biased by experimental approaches and it is spread in different trophic groups. We analyzed the empirical evidences of fungal diversity in fragmented landscapes, and proposed future perspectives for the study of these organisms under land use changes. Fungal diversity might be negatively affected by habitat fragmentation; however, this trend may differ in magnitude depending on fungal groups and their nutritional habits. In addition, due to the fact that fungal diversity at fragmented landscapes has been studied mainly through few indicators (e.g. isolation, area and edge effect); we propose incorporating the landscape structure and accurate spatio-temporal scales to the study of fungal diversity responses to fragmented landscapes. Together, this methodological refinement may allow improving knowledge on fungi when designing proper strategies for landscape management.

WITHDRAWN: Fungal diversity is negatively affected by habitat fragmentation: a meta-analysis

This article that has already been published in <Current Opinion in Microbiology, 37, June 2017 61-66>, 10.1016/j.mib.2017.03.015 has been withdrawn at the request of the editor and publisher. The publisher regrets that an error occurred which led to the premature publication of this paper. This error bears no reflection on the article or its authors. The publisher apologizes to the authors and the readers for this unfortunate error". The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

Immunophenotyping of Rabbit Testicular Germ and Sertoli Cells Across Maturational Stages

During testicular maturation, both Sertoli cells (SCs) and germ cells (GCs) switch from an immature to a mature immunophenotype. The reexpression of markers of immaturity in adults has been reported in cancer and in other testicular pathologies, in men as well as in animal species. Naturally affected with testicular cancer, rabbits have long been used in human reproductive research, but reports on the expression of testicular cell markers in this species are few and data about the immunophenotype of normal postnatal SCs and GCs are lacking. The aim of this study was to investigate the immunophenotype of SCs and GCs in the rabbit, from neonatal to adult age, using the antibodies anti-Müllerian hormone (AMH), vimentin (VIM), CKAE1/AE3 (cytokeratins [CKs]), desmin (DES), inhibin alpha (INH-α), placental alkaline phosphatase (PLAP), and periodic acid-Schiff (PAS) staining. In SCs, VIM was constantly expressed, and AMH and CKs expression was limited to neonatal and prepubertal age, whereas DES, INH-α, PLAP, and PAS were constantly negative. GCs were negatively stained for PLAP, PAS, and for the other markers. Results revealed analogies with human testicular immunophenotype, suggesting that rabbits could represent a potential experimental model for the study of human testicular pathology.

Spillover Events of Infection of Brown Hares (Lepus europaeus) with Rabbit Haemorrhagic Disease Type 2 Virus (RHDV2) Caused Sporadic Cases of an European Brown Hare Syndrome-Like Disease in Italy and Spain

Rabbit haemorrhagic disease virus (RHDV) is a lagovirus that can cause fatal hepatitis (rabbit haemorrhagic disease, RHD) with mortality of 80–90% in farmed and wild rabbits. Since 1986, RHDV has caused outbreaks in rabbits (Oryctolagus cuniculus) in Europe, but never in European brown hares (Lepus europaeus, EBH). In 2010, a new RHDV‐related virus, called RHDV2, emerged in Europe, causing extended epidemics because it largely overcame the immunity to RHDV present in most rabbit populations. RHDV2 also was identified in Cape hare (Lepus capensis subsp. mediterraneus) and in Italian hare (Lepus corsicanus). Here, we describe two distinct incidents of RHDV2 infection in EBH that occurred in Italy (2012) and Spain (2014). The two RHDV2 strains caused macroscopic and microscopic lesions similar to European brown hare syndrome (EBHS) in hares, and they were genetically related to other RHDV2 strains in Europe. EBHs are common in Europe, often sharing habitat with rabbits. They likely have been exposed to high levels of RHDV2 during outbreaks in rabbits in recent years, yet only two incidents of RHDV2 in EBHs have been found in Italy and Spain, suggesting that EBHs are not a primary host. Instead, they may act as spillover hosts in situations when infection pressure is high and barriers between rabbits and hares are limited, resulting in occasional infections causing EBHS‐like lesions. The serological survey of stocked hare sera taken from Italian and Spanish hare populations provided an understanding of naturally occurring RHDV2 infection in the field confirming its sporadic occurrence in EBH. Our findings increase the knowledge on distribution, host range and epidemiology of RHDV2.

Childhood Ataxia with Cerebral Hypomyelination Syndrome: A Variant of Patient with Early Childhood Onset Related to EIF2B3 Mutation

Childhood ataxia with central nervous system hypomyelination (CACH) syndrome is an autosomal recessive transmitted leukodystrophy characterised by early childhood onset and acute deterioration following febrile illnesses or head trauma. We describe the case of a child with early onset of CACH syndrome. He presented with cerebellar ataxia beginning around two years of age with mild mental retardation. MRI showed diffuse white matter signal changes with thinning of the corpus callosum.

[Methodological aspects of clinical and economic impact of vaccine interventions and HTA. Focus on HPV vaccination]

The aim of the present study is to analyze the methodological and technical aspects of Health Technology Assessment (HTA) as a tool for the clinical and economic impact of vaccine interventions, describe and comment the main studies at the national level, with a particular focus on HPV vaccination. The work was conducted in 3 phases: a) revision of the scientific literature, strictly linked to methodologies adopted in different studies on economic evaluations on HPV vaccines and analysis of Guidelines for building models for the economic assessment; b) analysis of the peculiarities and critical elements of economic evaluations in the field of vaccinology, from the clinical and epidemiological point of view, as well as the recognition of lack of knowledge on HPV infection dynamics; c) a comparative analysis of the two italian studies and of the results coming from them. Many differences between studies were found. Nevertheless, there is a general agreement on the economic profile of HPV vaccination for adolescent girls, if compared with the actual practice on the prevention of cervical carcinoma (pap-test screening). All the models showed a significant impact in terms of reduction of the incidence of cervical carcinoma and related mortality, in the long run, as well as a reduction of pre-cancer lesions and abnormal Pap tests. HTA approach has been recently recognized as a tool for decision making in vaccinology, and its methodologies and procedures are currently debated by public health experts. There is a strong need to continue the work in improving the model techniques of economic evaluations concerning HPV vaccination, as well as the adoption of homogeneous methods and standards, with the aim of helping the decision process in the field of Public Health.

[Paraneoplastic syndromes: a review]

Modern oncology often obtains good results against earlier neoplasms, whilst it's still in difficulties against the advanced ones. The knowledge of paraneoplastic syndromes is crucial both to cure patients and to do an earlier diagnosis. When we recognize a paraneoplastic syndrome that comes before the clinic beginning of a neoplasm, perhaps we save a life. This review discusses all the main paraneoplastic syndromes, focusing mainly on their clinical aspect and reminding the most commonly associated cancers.

Immunohistochemical identification of Encephalitozoon cuniculi in phacoclastic uveitis in four rabbits

PURPOSE

Encephalitozoon cuniculi is a microsporidium with a wide range of mammalian hosts. In rabbits it can be responsible for cataract and lens-induced uveitis (LIU). The aim of this study was to provide specific immunohistochemical demonstration and localization of E. cuniculi within the eye, in rabbits with LIU.

MATERIAL AND METHODS

Four rabbits were presented with a white mass in the eye and iris discoloration. Complete ophthalmic examinations were performed and a presumptive diagnosis of LIU was made in all cases. Initial therapy with a topical steroid, atropine and systemic enrofloxacin was instituted while serologic (IFA or ICA tests) and cytologic lab results were pending. The final outcome in all cases was enucleation. Routine histology and immunohistochemistry (ABC method) with an antiserum anti-Encephalitozoon cuniculi were performed.

RESULTS

Indirect immunofluorescence performed on one rabbit serum expressed a titer of 1 : 32; carbon immunoassay on the serum of the other three rabbits expressed a titer of 1 : 5120 in one, and a titer of 1 : 2560 in the other two cases. Histologically, an intraocular, locally extensive pyogranulomatous infiltration that partially filled the posterior chamber, encasing a wide anterior lens capsule break, was detected in all cases. Immunohistochemically, spores reacting with anti-Encephalitozoon cuniculi antiserum were present in all specimens, occasionally within macrophages and lens epithelial cells.

CONCLUSION

Detection of E. cuniculi in rabbits with phacoclastic uveitis has been investigated in the past with different methods. Based on our results, we suggest that immunohistochemistry should be regarded as a useful tool both for specific demonstration of E. cuniculi and for its localization within tissues.

Cilia-associated respiratory (CAR) bacillus infection in conventionally reared rabbits

This study was designed to investigate the prevalence of Cilia-associated respiratory (CAR) bacillus infection in rabbits reared for meat production in Italy and to correlate the presence of CAR bacillus with inflammatory lesions of the respiratory tract. Seventy health, 3-month-old, New Zealand White rabbits, raised in 10 different rabbitries in Northern Italy were randomly selected at slaughter. No gross lesions were found at necropsy in any rabbit. In each animal, the trachea and lungs were sampled, fixed in 10% formalin, embedded in paraffin and stained with the Warthin-Starry method to evaluate the presence of CAR bacillus, and with haematoxylin and eosin to evaluate the presence of inflammatory lesions. CAR bacillus was present in 50 out of 70 rabbits (71.4%) with a prevalence of the infection that varied from 30% to 100% in the seven rabbitries. CAR bacillus was present both in the trachea and bronchi in 23 cases (32.8%), only in the trachea in 24 cases (34.3%) and only in the bronchi in three cases (4.3%). Inflammatory lesions were found in the trachea (22 cases, 31.4%) and the bronchi (58 cases, 82.8). There was a strong, statically significant correlation between the presence of CAR bacillus in the bronchi and bronchial inflammatory lesions (P < 0.0001). This study indicates that CAR bacillus infection is widespread in conventionally reared rabbits in Italy and that a possible correlation exists between the presence of CAR bacillus and bronchial inflammatory lesions.

Simultaneous influenza and pneumococcal vaccination in elderly individuals

The study was performed to evaluate the effects of influenza and pneumococcal vaccines administered alone or in combination. 124 elderly subjects living in community were vaccinated either with influenza split vaccine or with pneumococcal 23-valent or with both vaccines at the same time in different sites. Sera were tested for hemoagglutination inhibiting antibodies for influenza and for antibodies against 23-valent vaccine for streptococcus pneumoniae. No side effects were observed in the vaccinated population. Serological results indicated that influenza vaccine increased significantly antibody levels. No difference was observed between the group which received influenza vaccine alone and that which received influenza and pneumococcal vaccines associated, considering either G.M.T or the percentages of protected individuals or the percentages of subjects who seroconverted. When pneumococcal vaccine was administered at the same time with influenza vaccine, there was a not statistically significant reduction in both mean antibody concentration and mean fold increase. It is concluded that the simultaneous administration of influenza and pneumococcal vaccines to elderly individuals, including subjects at risk, is safe, effective and economically advantageous.

Immune response to a booster dose of enhanced potency inactivated polio vaccine administered in association with HBV vaccine in adolescents

The immunogenicity and reactogenicity of a booster dose of enhanced potency inactivated polio vaccine (EIPV) were evaluated in 492 healthy 12 year old adolescents. The booster was administered at the same time as the HBV vaccine compulsory in Italy at this age. Blood samples and questionnaires on reactogenicity were collected over 9 months. Analysis of pre-vaccination immunity showed that 97.4% of the subjects were protected against all polio types, 1.9% were negative for two polio types and 0.6% for one. After vaccination 98.4% of the vaccinees showed a significant increase ( > or = 4 times) of antibody titre; the geometric mean titres (GMT) were markedly higher than before vaccination, particularly for poliovirus type 3. The polio booster dose did not affect HBV vaccination. An anti-HBs response > 10 mIU ml-1. (GMT = 2951 mIU ml-1) was observed in 781 (98.6%) of 792 vaccinees (492 given EIPV+HBV and 300 given only HBV) 9 months later. Only mild local and rare general reactions were noted for both the vaccines studied. These data confirm the suitability and efficacy of an EIPV booster dose and HBV vaccination in adolescents.

[Transmission of measles during four outbreaks in a partially vaccinated population]

All measles cases occurred between 1989 and 1991 in the territory of the Local Health Unit 10--Marche Region--Italy, were studied in order to evaluate the characteristics of the disease and the transmission mechanisms. A total of 4 outbreaks were evidenced: 2 occurred in a 40,000 population municipality (with 46 and 87 cases, respectively), 1 in a 10,000 population municipality (with 35 cases) and 1 in two closely-related municipalities of 4,600 population (with 67 cases). The immune status of children between 1 and 10 years of age was evaluated adding the number of vaccinated children to the number of those who resulted having had the disease. Immune children were between 52.3% and 89.1%. During the outbreaks, the percentage of cases occurred in subjects over 10 years of age was, in total, 65.5. No cases needed hospitalization and only one case occurred in a vaccinated boy. In 189 cases the subject who presumably transmitted the disease was identified. Transmission occurred: within the school in 51.8% of the cases; within the family in 30.7%; during social activity in 10.0%; from inhabitants of the same house in 7.4%. The epidemiology of measles, in the area of this study, seems different from that described in the United States.

Streptococcus faecalis susceptibility to amiloride depends on medium pH

Amiloride is one of the major molecular probes in basic and applied investigations on the physiology of cation transport in animal cells. In these cells the drug also exerts growth inhibitory activity. Recently, we discovered that amiloride causes growth inhibition also on bacterial cells. In this paper we report that medium pH influences amiloride activity on Streptococcus faecalis. The lowering of external pH causes a drop in the susceptibility of this bacterium to amiloride up to an almost complete resistance. This finding, constitutes a novel aspect of the in vitro experimental pharmacology of this diuretic potentially useful also in clinical pharmacology and in animal cell investigations.

Whole-cell bacterial peroxidase test with isoproterenol as the hydrogen donor

The beta-adrenergic compound isoproterenol was used as oxidizable reagent in a whole-cell assay for the detection of bacterial peroxidase activities. Isoproterenol has been shown to constitute a useful reagent for detecting peroxidase activities in enzymatic tests, utilizing standard purified enzymes, and in the microbiological application proposed. The procedure developed is simple and rapid to perform. In contrast to currently used whole-cell tests for bacterial peroxidases, the assay described here does not need preliminary permeabilization; moreover, the compound utilized does not have related toxicological problems. Therefore, the isoproterenol assay may represent a low-cost safe additional peroxidase test in clinical bacteriology.

Chlorpromazine as permeabilizer and reagent for detection of microbial peroxidase and peroxidaselike activities

Chlorpromazine was used to perform a test for the detection of microbial peroxidase activities. The compound acts as both a cell permeabilizer and a reagent in the procedure developed which allows the detection of peroxidase and peroxidase like reactions both semiquantitatively in whole cell determinations and quantitatively in cell-free supernatants.

[Contrast dose and signal/noise ratio in digital angiography]

In a digital angiographic system the variations of the signal to noise ratio in relation to the contrast medium quantity and to the exposure data are analyzed. On these basis, the greater flexibility of the digital angiographic equipments in comparison with conventional ones is underlined.

Characterization of erythroid and granulocyte monocyte progenitors in human cord blood

Some characteristics of both erythroid and granulocyte monocyte progenitors in human cord blood were compared to those in adult blood and bone marrow. The number of progenitors in cord blood was higher than that in adult blood and bone marrow. Most colonies in cord blood culture were monocyte-macrophage, whereas those from adult blood were largely eosinophilic. Cord blood progenitors had a slower sedimentation velocity than that reported for marrow, but sedimented faster than that for adult blood. A significant proportion of progenitors in cord blood as well as adult marrow was found to be in the DNA synthetic phase of the cell cycle whereas progenitors in adult blood were not. Cord blood BFU-E were more resistant than adult blood BFU-E but cord blood CFU-GM were not different from adult blood CFU-GM with regard to radiation sensitivity. Cord blood CFU-GM appeared to be more radio-resistant than adult marrow GFU-GM. From these results is seems clear that progenitors in cord blood differ in some aspects from those in adult blood and bone marrow.

Ontogeny of the granulocyte/macrophage progenitor cell (GM-CFC) pools in the beagle

The pattern of development of the granulocyte/macrophage progenitor cell (GM-CFC) pools in the course of canine ontogeny was studied by means of the agar culture technique. Colony formation was stimulated by colony stimulating activity (CSA) in serum from lethally irradiated dogs in combination with erythrocyte-depleted peripheral blood leukocytes from normal adult dogs. The colonies thus obtained in cultures from the different organs were in general large (estimated maximum 50 000 cells) and consisted predominantly of mononucleated macrophages, suggesting that, in these studies, a progenitor cell with high proliferative potential (HPP-CFC) has been monitored. In the yolk sac, a transitory GM-CFC pool became established between day 23 and day 48 of gestation, reaching maximum numbers of approximately 41 X 10(3) per organ on days 36/37. At the same time the GM-CFC concentration in blood collected from the heart also reached a maximum of about 31 X 10(3)/ml, indicating its carrier function for the migration of GM-CFC. In the liver a quasi-exponential increase in the GM-CFC numbers took place between days 36/37 and days 57 to 59 when a total of about 15.2 X 10(6) was found but thereafter and up to day 4 post partum the GM-CFC numbers decreased by almost two orders of magnitude. A continuous increase in the GM-CFC numbers was found in the spleen between day 42 of gestation and day 4 post partum when a maximum of 5.1 X 10(6) to 8.7 X 10(6) was reached. In contrast to the GM-CFC numbers in the liver, the splenic GM-CFC dropped only by 50% of peak values when the dogs reached adulthood. The bone marrow always had the highest incidence of GM-CFC, the concentration per 10(6) cells being 18.7 X 10(3)/10(6) cells on days 45/46, the earliest time point at which cultures could be set up. The absolute GM-CFC numbers in the two femora increased continuously between days 45/46 and day 4 post partum in parallel with the growth of the bones. In the thymus a relatively small population of GM-CFC developed between days 42 and 48 of gestation that was kept quite constant at average numbers between 13 X 10(3) and 30 X 10(3) up to day 4 post partum.

Survival of transfused cryopreserved granulocytic progenitor cells (CFU-C) in recipient circulation

We have studied the pattern of CFU-C disappearance from the peripheral blood of normal and total-body-irradiated dogs given cryopreserved cell suspensions from bone marrow, foetal liver and peripheal blood containing known numbers of CFU-C under an autologous and allogeneic donor-recipient relationship. Only a small fraction of infused donor CFU-C could be detected in the circulation of recipients at the end of the infusion. There was an exponential fall in circulating CFU-C, indicating random loss of infused CFU-C. The CFU-C disappearance pattern in each experimental group was reproducible. The mean half life of autologous blood derived CFU-C in the circulating blood of normal recipients was 8.2 min and the mean blood CFU-C turnover was calculated to be 9.3 X 10(5) CFU-C/kg per day.

Chronic myelocytic leukaemia: cytogenetical studies on haemopoietic colonies and diffusion chamber cultures

In 20 patients with chronic myelocytic leukaemia in the chronic phase or in blast crisis, several in vitro (CFU-C, BFU-E) and in vivo (diffusion chamber) culture techniques were used to demonstrate the existence of a still diploid cell clone. In 4 out of 12 patients in the chronic phase, Ph1-negative metaphases were found in the various cultures for haemopoietic progenitor cells but not in the standard suspension cultures used for cytogenetics. However, all the 8 patients investigated during blast crisis had only Ph1-positive and other abnormal clones, indicating the loss of the diploid clone during progression of the disease.

Promotion of erythropoietic bursts in culture of human bone marrow by blood-derived Mononuclear cells

In this report we give evidence that the addition of different amounts of irradiated mononuclear cells (MNC) from normal blood to bone marrow cell cultures containing erythropoietin produces an increase in number and size of erythropoietic bursts proportional to the number of irradiated MNC added. There was no consistent difference in the use either of autologous or of allogeneic MNC as burst-promoting activity source in normal individuals. Plating efficacy studies demonstrated that the number of BFU-E detected had a linear relationship to the number of bone marrow cells plated when 5 X 10(5) blood MNC were present as BPA source. A comparison between different preparations of human leukocyte conditioned media and 5 X 10(5) irradiated MNC, demonstrated that in all experiments irradiated cells stimulated the growth of a higher number of marrow-derived BFU-E. Therefore the use of 5 X 10(5) irradiated MNC from normal blood is proposed as standard BPA source in human bone marrow erythropoietic cultures.

Effect of blood derived monocytes on the promotion of in vitro erythropoietic colony growth in human bone marrow cultures

The effect of monocytes on the promotion of erythropoietic burst formation in human bone marrow methylcellulose cultures was studied in a burst-promoting activity (BPA)-poor system. Irradiated Ficoll-Isopaque separated blood mononuclear cells stimulated BFU-E growth proportionally to the number of irradiated cells added. Monocyte-depleted mononuclear cells stimulated as well as total mononuclear cells. Monocyte-concentrates stimulated when added at low concentrations. Monocyte-depleted mononuclear cells, although stimulatory at higher concentrations, did not stimulate at the concentrations used for monocyte-concentrates.

The effects of calusterone on hemopoiesis in mice after busulfan-induced suppression of hemopoietic stem cells

Studies were undertaken in mice to determine the effect of calusterone (a weakly androgenic steroid) on hemopoiesis. Animals were myelosuppressed with a single injection of the alkylating agent busulfan and subsequently treated with varying courses of calusterone. Simultaneous injection of calusterone did not prevent the rapid decline in CFU-S or CFU-C. Daily administration of calusterone for 12 to 14 days after busulfan had little influence on bone marrow cellularity; however, a twofold increase in peripheral blood neutrophils was observed. Bone marrow CFU-S and CFU-C were twofold to threefold higher after 8 to 14 days of treatment with calusterone, but there were no progressive increments in these hemopoietic stem cells during this time interval. In contrast to the granulocyte series, erythroid recovery was rapid after busulfan. Marrow erythroid precursors and CFU-E returned to normal levels by day 8. Daily treatment with calusterone accelerated recovery and led to an overshoot in these parameters of marrow erythropoiesis. Although an early course of calusterone treatment had only modest effects on CFU-S and CFU-C, delayed treatment was clearly stimulatory. A 10-day course of calusterone from days 14 to 24 after busulfan increased bone marrow CFU-S and CFU-C from 5% to 23% of controls to near normal values. Thus calusterone appears to stimulate all classes of hemopoietic progenitor cells. Its effects after busulfan are highly time-dependent, with greatest activity observed in those cellular compartments undergoing proliferative expansion.

[Erythrocyte membrane in Duchenne muscular dystrophy. I. Sensitivity to lysolecithin in dystrophic patients and their families]

The percentage of echinocytes in the blood from patients affected by Duchenne muscular Distrophy was studied after red cells treatment with L-alpha-lysophosphatidylcholine. The echinocyte content was significantly higher in Duchenne patients and in the components of their families, as previously demonstrated is lower in Stainert patients. The sensitivity to lysophosphatidylcholine in Duchenne muscular Distrophy is a diagnostic test for carrier condition