Long-Term Sensory Function 3 years after Minimally Invasive Repair of Pectus Excavatum with Cryoablation

INTRODUCTION

Minimally invasive repair of pectus excavatum (MIRPE) with intercostal nerve cryoablation (Cryo) decreases length of hospitalization and opioid use, but long-term recovery of sensation has been poorly described. The purpose of this study was to quantify long-term hypoesthesia and neuropathic pain after MIRPE with Cryo.

METHODS

A prospective cohort study was conducted single-institution of patients ≤21 years who presented for bar removal. Consented patients underwent chest wall sensory testing and completed neuropathic pain screening. Chest wall hypoesthesia to cold, soft touch, and pinprick were measured as the percent of the treated anterior chest wall surface area (TACWSA); neuropathic pain was evaluated by questionnaire.

RESULTS

The study enrolled 47 patients; 87% male; median age 18.4 years. The median bar dwell time was 2.9 years. A median of 2 bars were placed; 80.9% were secured with pericostal sutures. At enrollment, 46.8% of patients had identifiable chest wall hypoesthesia. The mean percentage of TACWSA with hypoesthesia was 4.7 ± 9.3% (cold), 3.9 ± 7.7% (soft touch), and 5.9 ± 11.8% (pinprick). Hypoesthesia to cold was found in 0 dermatomes in 62%, 1 dermatome in 11%, 2 dermatomes in 17% and ≥3 dermatomes in 11%. T5 was the most common dermatome with hypoesthesia. Neuropathic symptoms were identified by 13% of patients; none required treatment.

CONCLUSION

In long-term follow up after MIRPE with Cryo, 46.8% of patients experienced some chest wall hypoesthesia; the average TACWSA with hypoesthesia was 4-6%. Hypoesthesia was mostly limited to 1-2 dermatomes, most commonly T5. Chronic symptomatic neuropathic pain was rare.

LEVEL OF EVIDENCE

Level IV.

A Prospective Study of Sensory Changes in Pediatric Patients After Minimally Invasive Repair of Pectus Excavatum With Cryoablation

BACKGROUND

Cryoablation during minimally invasive repair for pectus excavatum (MIRPE) reduces opioid use and hospital length of stay. Skin hypoesthesia of the chest wall also occurs. This study sought to determine the frequency, onset, duration, and location of sensory changes and neuropathic pain after cryoablation.

METHODS

A prospective study was conducted on patients aged ≤21 years undergoing MIRPE with cryoablation of T3 to T7 dermatomes bilaterally for 120 s at a single institution between March 2021 to December 2022. Patients underwent sensory testing of the chest wall and neuropathic pain surveys (S-LANSS) preoperatively and then postoperatively for 6 months. Incidence and duration of hypoesthesia and neuropathic pain were evaluated.

RESULTS

Of 61 patients enrolled in the study, 45 completed evaluations at six months postoperatively. All patients had skin hypoesthesia on postoperative day (POD)1. The mean percentage of the treated anterior chest wall surface area (TACWSA) with hypoesthesia to cold stimulus was 52% (±29.3) on POD 0 and 55% (±19.7) on POD 1. Sensation returned over time, with hypoesthesia affecting 11.1% (±15.5) TACWSA at 6 months. At study completion 58% of patients (26/45) had complete return of sensation; hypoesthesia was found at: 1 dermatome 13% (2/45), 2 dermatomes 22% (11/45), and 3 dermatomes 4% (2/45). Neuropathic pain (S-LANSS ≥12) was documented in 16% (9/55) of patients at hospital discharge but decreased to 6.7% of patients at 6 months.

CONCLUSION

Onset of skin hypoesthesia after cryoablation occurred on POD0 and affected 52% of the TACWSA. All patients experienced return of sensation to varying degrees, with 58% experiencing normal sensation in all dermatomes by 6 months. The etiology of persistent hypoesthesia to select dermatomes is unknown but may be related to operative technique or cryoablation. Chronic neuropathic pain is uncommon.

LEVEL OF EVIDENCE

II.

TYPE OF STUDY

Prognosis Study.

Social representations of intellectual disability; a comparison between cultures

OBJECTIVES

People with Intellectual disability consistently appear to be one of the most looked-down upon and repressed subgroups of society in many cultures. The main aim of this study was to compare social representations of intellectual disability in its various aspects between different cultures.

MATERIALS AND METHODS

The study was conducted in four different sites: Beirut-Lebanon, Algiers-Algeria, Tours-France and Namur-Belgium. Participants were asked to complete a questionnaire evaluating social representations of intellectual disability.

RESULTS

A total of 755 participants consented to take part in the study. Gender only affected social representations in the Lebanese population. Overall, Algerians appeared to have the least positive social representations and Lebanon to have more positive attitudes, while France and Belgium tended to have the most favourable representations.

DISCUSSION AND CONCLUSIONS

Findings highlight the imbalance between a European and a non-European country showing the importance of developing tailored interventions to improve general attitudes towards intellectual disability.

Clinical Characteristics and Treatment Patterns of Open Hand Fractures in the Pediatric Population

BACKGROUND

Open hand fractures are one of the most common injuries in the pediatric population. These injuries are at higher risk of infection, especially in cases of frank contamination. Several studies on adult hand fractures are available in the literature; however, pediatric open hand fractures have yet to be extensively studied. This study aimed to define pediatric open hand fracture's demographics, clinical characteristics, and treatment patterns.

METHODS

Using the Protected Health Information database, pediatric patients (<18 y old) with the diagnosis of open hand fracture from June 2016 to June 2018 were extracted. Demographic, treatment, and follow-up data were collected. Clinical outcomes included readmission and postoperative infection rates.

RESULTS

There were a total of 4516 patients who met the inclusion criteria; the median age was 7 years (interquartile range: 3 to 11); 60% males; 60% white. Displaced fractures occurred in 74% of patients, with the right hand (52%) and middle finger (27%) predominance. The most common mechanism of injury was a crushing injury in-between objects (56%). Associated nerve injury occurred in 78 patients (4%) and vascular injury in 43 patients (2%). Open reduction and internal fixation were performed in 30% of patients. Cephalosporins were the most commonly prescribed antibiotics (73%), followed by aminopenicillins (7%). Nine patients had complications related to surgical intervention (0.2%), and postoperative infection occurred in 44 patients (1%).

CONCLUSIONS

Pediatric open hand fractures most often occur during childhood and more frequently in males. These fractures tend to be more distal and displaced; reduction and fixation are required in one-third of the cases. Despite the absence of treatment guidelines and variability, this injury exhibits low complication rates.

LEVEL OF EVIDENCE

Level III, retrospective study.

Comparison over 25 years of the burden of familial hypercholesterolemia on hospitalizations for coronary heart disease in a French-Canadian founder population

Background

Over the last 25 years, effective treatments, such as potent statins, ezetimibe and PCSK9 inhibitors have gradually emerged to treat heterozygous familial hypercholesterolemia (FH) and guidelines have been progressively developed internationally to promote FH health surveillance, early diagnosis and optimal clinical management. However, the impact of these measures on the burden of FH is not well documented. Although recent genetic and epidemiological studies suggest that the prevalence of familial hypercholesterolaemia (FH) is approximately twice than initialy expected (1:250) (1), it remains significantly higher among French Canadians (FC) (2,3).

Purpose

To compare over 25 years the management and burden of FH among patients hospitalized for an acute coronary heart disease (CHD) event in a FC founder population with a high prevalence of FH.

Methods

Lipid profiles, cardiovascular risk factors, lipid management and FH status of 2,029 FC patients consecutively hospitalized for an acute CHD event between 2017 and 2022 (2022 Cohort) were compared to those of 2,506 patients with angiographically-confirmed CHD who were admitted between 1995 and 1998 (1998 Cohort) (4). FH status was based on molecular, Simon Broome or FH Canada (5) criteria. Statistical comparisons were made using Chi-square and Student's t-tests for independent samples.

Results

Over a 25-year interval, most patients hospitalized for CHD were men (74.5% in 1998 vs 73.4% in 2022). At the time of admission, 23.0% of CHD patients had LDL-Cholesterol levels &gt;5.0 mmol/L in 1998 compared to 1.3% in 2022 (p&lt;0.001). FH was diagnosed in 9.6% of patients in the 1998 cohort compared to 5.5% in 2022 (p&lt;0.001). Overall, the prevalence of obesity, type 2 diabetes and uncontrolled hypertension tended to be higher in 1998, including in FH (p&lt;0.05). The proportion of FH patients hospitalized for CHD who were treated with a statin or a combination of lipid-lowering agents at the moment of admission was 28.4% in 1998 compared to 61.2% in 2022 (p&lt;0.001). FH patients hospitalized for CHD were significantly older in 2022 than in 1998 (59.03±11.17 vs 50.14±11.32 years; p&lt;0.001). Accordingly, the prevalence of premature CHD requiring an hospitalization significantly decreased from 1998 to 2022 in FH (64.3% vs. 44.1%, p&lt;0.001).

Conclusions

Over a 25-year period, FH patients hospitalized for CHD tend to be older and contribute to a lower proportion of hospitalizations. Despite significant improvement in treatment, FH diagnosis and management remain sub-optimal, even in a founder population where FH represents a significant population burden.

Funding Acknowledgement

Type of funding sources: None.

Medical Student Perspectives on Undergraduate Oncology Education in the UK

AIMS

The British Oncology Network for Undergraduate Societies (BONUS) surveyed students who attended an oncology revision day to determine their views on the current quantity, quality and type of curriculum-based oncology teaching they have experienced.

MATERIALS AND METHODS

Students attending two BONUS revision days received a questionnaire assessing their experience of oncology teaching within the medical curriculum and interest in pursuing a future career in oncology using a 10-point Likert scale. Data were collected with informed consent to be anonymised and used for research. Student demographics and qualitative and quantitative data about experiences of oncology education were analysed.

RESULTS

In total, 451 students registered to attend the revision days. After removal of duplicates, non-responders and non-UK participants, responses from 153 students studying across years 1-6 at 22 UK medical schools were analysed. The mean quantity of oncology lectures students reported receiving was 8.9 hours and the mean quantity of clinic/ward-based oncology teaching was 7.5 hours. Ninety (62.1%) of the 145 students who responded to the relevant question reported that they had received dedicated teaching in oncology. Students who had received dedicated oncology teaching reported a statistically significantly higher mean quality 6.1 (95% confidence interval 5.6-6.5) versus 5.0 (95% confidence interval 4.3-5.5; P = 0.003) and quantity 5.2 (95% confidence interval 4.7-5.6) versus 4.3 (95% confidence interval 3.7-4.9; P = 0.03) of oncology teaching compared with those who had not received this.

CONCLUSION

Appropriate oncology education is essential for all medical students due to the high prevalence of cancer. All future doctors need the appropriate knowledge and communication skills to care for cancer patients. Our analysis provides quantitative evidence to support the value of specialist oncology teaching within the medical school curriculum in improving student-reported experience. National student-led revision days and events may widen interest in a future career in oncology and aid collaboration between oncology societies. It is important for the general undergraduate medical curriculum to integrate specialty content. An integrated curriculum should facilitate a holistic approach that spans prevention, screening, treatment and palliation rather than being split by subspeciality.

4944The contribution of familial hypercholesterolemia (FH) to premature coronary artery disease decreased by 2-fold between 1998 and 2018 in a founder population with high prevalence of FH

Background

Familial hypercholesterolemia (FH) is an autosomal dominant trait associated with high risk of premature coronary artery disease (CAD). The worldwide prevalence of FH is estimated at 1:250 to 1:500. In certain populations, including French Canadians (FC), the prevalence is significantly higher however. From 1995 to 1998, FH contributed to 9.6% of angiographically proven CAD in a FC founder population, the burden being the highest in men aged <50 years (20.6%). In the past 2 decades, powerful statins, ezetimibe and other low-density lipoprotein-Cholesterol (LDL-C) modulators, such as PCSK9 inhibitors, have been progressively introduced and several FH diagnosis scoring systems or guidelines have been developed and disseminated in order to facilitate FH recognition and management. The impact of these measures on the FH burden is however not documented.

Purpose

To compare the burden of FH twenty years apart in FC patients hospitalized for CAD.

Methods

Lipid profiles, cardiovascular risk factors and FH status of 1,132 FC patients who were hospitalized for a CAD event and who consecutively attended the cardiovascular disease clinic in 2017 and 2018 were compared to those of 2,506 who consecutively presented angiographically proven CAD two decades ago. FH status was based on Simon Broome and FH Canada definitions. In 1998, all consenting CAD patients were also molecularly screened for the most prevalent FH causing mutations in FC. Comparisons between groups were performed using Chi-square and independent samples Student's t-test.

Results

Most patients in both cohorts were males (74.5% vs 73.9% in 1998 vs. 2018, respectively). At admission, mean LDL-C (± SD) was 3.99±1.67 in 1998 vs. 2.22±1.06 in 2018 (p<0.001). The proportion of patients who were treated with a statin or another lipid lowering agent was 32.9% in 1998 compared to 67.6% in 2018 (p<0.001) and the drug regimen was also significantly different. In 1998, 24.6% of patients had LDL-C >5.0 mmol/L at admission compared to 4.2% in 2018. Definite FH was diagnosed in 9.6% of patients in the 1998 cohort compared to 4.7% in the 2018 cohort (p<0.001). FH patients hospitalized for CAD were significantly older in 2018 than in 1998 (56.3±11.3 vs. 49.2±10.9 in men, p=0.001; 61.1±11.8 vs. 53.2±12.3 in women, p=0.02). In the same period, the relative burden of diabetes and other lipid disorders, including high-density lipoprotein dysmetabolism significantly increased (p<0.001).

Conclusions

Over a period of 20 years, in a founder population with a high prevalence of FH, the contribution of FH to hospitalizations for CAD decreased by 2-fold and affected patients now tend to be hospitalized at an older age than 2 decades ago. This suggests that early diagnosis and more effective management of FH in the last 2 decades have contributed to significantly decrease its burden.

Acknowledgement/Funding

ECOGENE-21, Amgen, Sanofi

[Cochlear implants in elderly: performance outcomes in the long term]

OBJECTIVES

To study and compare the evolving capacities of speech discrimination with cochlear implants in older patients compared to patients implanted at a younger age.

METHODOLOGY

A retrospective study comparing a group of 52 patients aged over 65 with a control group of 58 patients aged between 30 and 50 years, followed for 5 years after implantation. We analyzed and compared the evolution of speech discrimination in silence (disyllabic words, sentences) and noise (sentences, S/N ratio: +10 dB) after implantation.

RESULTS

In the group of elderly patients, the speech discrimination in silence remains stable over time (for disyllabic words, score at 6 months: 72.8 +/- 20.2%; score at 5 years: 73.7% +/- 19.7). Discrimination in noise tends to improve (mean score at 6 months: 70.5% +/- 21.5; score at 5 years: 76.9% +/- 16.9). The results obtained are in silence are comparable to the results of the group of patients aged between 30 and 50. In noise, their performance remains lower than the control group (mean differences between scores: -10.8; confidence interval at 95%: -17.9, -5.3).

CONCLUSION

The cochlear implant is effective over the long term in elderly patients, for speech discrimination in quiet and in noise. In silence, their performance is comparable to younger patients with implants.

Non-Hodgkin's lymphomas with Burkitt-like cells are associated with c-Myc amplification and poor prognosis

Out of 344 patients with newly diagnosed non-Hodgkin's lymphoma (NHL), this study identified 16 patients presenting Burkitt-like cells (BLCs) after cytological and/or histological review. Conventional cytogenetic analysis showed at diagnosis complex chromosomal abnormalities in 13 cases and a normal karyotype in three cases. However, neither t(8;14)(q24;q32) nor the variants t(2;8)(p12;q24) or t(8;22)(q24;q11) was detected. FISH studies showed c-MYC amplification in all cases with four to more than seven copies in 10 - 77% metaphase or inter-phase cells. This study did not observe any gene fusion signal for c-MYC/IgH excluding a t(8;14) translocation and partial tri or polysomy of chromosome 8. It also excluded in that cases a break apart for the c-MYC locus. This study also never detected IgL/c-MYC, IgK/c-MYC or X-c-MYC. The BLCs were present whatever the lymphoma sub-type: follicular lymphoma (FL) was diagnosed in six out of 16 patients, mantle cell lymphoma (MCL) in four out of 16 patients, marginal zone lymphoma (MZL) in two out of 16 patients and diffuse large B-cell lymphomas (DLBCL) in three out of 16 patients. One additional patient presented a T-cell lymphoma. The clinical course was aggressive with a poor prognosis, as death occurred in nine patients, within 6 months after diagnosis for eight of them. These data could suggest a sub-group of NHL patients (15 B-NHL, 1 T-NHL) have been identified with a poor prognosis characterized by the association of Burkitt-like cells and c-MYC amplification without t(8;14)(q24;q32) or its variants. The possibility that this profile may represent a distinct morphologic NHL sub-set remains to be determined on a large cohort of patients.

HsS versus a balanced salt solution as a corneal wetting agent during routine cataract extraction and lens implantation

PURPOSE

To evaluate HsS (elastoviscous hylan surgical shield, 0.45%) as an alternative to repeated corneal irrigation with a balanced salt solution during cataract surgery.

SETTING

York Finch General Hospital, Toronto, Ontario (Center A), and Centre Hospitalier de St. Laurent, St. Laurent, Quebec (Center B), Canada.

METHODS

This dual-center, randomized, prospective clinical trial comprised 60 patients (40 at Center A; 20 at Center B) who had routine small incision cataract surgery (Center A, endolenticular phacoemulsification; Center B, Khoury manual phacofragmentation) with in-the-bag implantation of a posterior chamber intraocular lens. The corneal irrigating fluid was randomly assigned to be HsS or a balanced salt solution. The frequency of required applications, duration of efficacy of each application, and assessment of corneal moisture, clarity, transparency, and reflection in the HsS and balanced salt solution groups were recorded and compared.

RESULTS

Mean frequency of applications was 13.9 per procedure in the balanced salt solution group and 1.3 per procedure in the HsS group (P = .0001). Mean duration of effectiveness per application was 23.4 minutes for HsS and 2.0 minutes for balanced salt solution (P = .0001). No significant differences in safety or effect on corneal health were observed between the two solutions.

CONCLUSION

The HsS was significantly more effective than a balanced salt solution in maintaining corneal moisture, clarity, and transparency. The use of HsS may be a safer, more effective option in ophthalmic surgery because it minimizes the obstructed visualization of the surgical field caused by frequent corneal irrigation and loss of surgeon concentration.

Direct effects of halothane on coronary blood flow, myocardial oxygen consumption, and myocardial segmental shortening in in situ canine hearts

Previous in vivo studies of the coronary vascular effects of halothane (HAL) were complicated by varying hemodynamic conditions and global cardiac work demands. Accordingly, the current study evaluated changes in coronary blood flow (CBF) and associated variables during selective intracoronary administrations of HAL in in situ canine hearts using an extracorporeal-controlled pressure perfusion system. Findings during HAL were compared to those during isoflurane (ISO). The left anterior descending coronary artery (LAD) of 8 open-chest dogs anesthetized with fentanyl and midazolam was perfused at constant pressure (109 +/- 2 mm Hg) with HAL-free arterial blood or with blood equilibrated in an extracorporeal oxygenator with HAL (0.5%, 1.0%, 2.0% in 95% O2-5.0% CO2). In the LAD bed, measurements of CBF were obtained with an electromagnetic flowmeter and used to calculate myocardial oxygen consumption (MVO2). Percent segmental shortening (%SS) was measured with ultrasonic crystals. Changes in CBF by HAL were compared to those during maximal vasodilation with adenosine. Separate studies (n = 5) were performed using 1.4% [1 minimum alveolar anesthetic concentration (MAC)] ISO and the findings compared to those during an equianesthetic (1.0%) concentration of HAL. HAL caused concentration-dependent increases in CBF, and decreases in MVO2 and %SS. With 2.0% HAL, the level of CBF was 50% of the maximal adenosine-induced response. At equianesthetic concentrations, HAL caused increases in CBF that were one-third of those caused by ISO, while the decreases in MVO2 and %SS caused by the drugs were not significantly different.(ABSTRACT TRUNCATED AT 250 WORDS)

Tumor necrosis factor alpha (TNF alpha) downregulates c-kit proto-oncogene product expression in normal and acute myeloid leukemia CD34+ cells via p55 TNF alpha receptors

Tumor necrosis factor alpha (TNF alpha), as a modulator of hematopoiesis, interacts with many growth factor receptors, such as interleukin-3, granulocyte-macrophage colony-stimulating factor (CSF), and granulocyte-CSF receptors. Here, we studied the interactions between TNF alpha and the stem cell factor (SCF) receptor, c-kit, in normal CD34+ hematopoietic progenitors and their leukemic counterpart, ie, acute myeloid leukemic (AML) CD34+ cells coexpressing c-kit antigen. The results showed that (1) incubation of normal bone marrow mononuclear cells with 200 U/mL rhTNF alpha for 20 hours induced a diminution of 31.2% +/- 5.2% of CD34+ cells coexpressing c-kit; (2) the same decrease was observed using purified CD34+ cells and, furthermore, their proliferative response to SCF was inhibited by 31.5% +/- 7.3% after exposure to TNF alpha; (3) similar experiments performed on CD34+ c-kit+ AML cells from 11 patients gave comparable results. Further analysis at the mRNA level indicated that TNF alpha decreased c-kit mRNA transcripts. Moreover, using monoclonal antibodies against the two types of TNF alpha receptors, p75 and p55, we showed that the downregulation of c-kit proto-oncogene product by TNF alpha, on normal and leukemic CD34+ cells, was exclusively mediated by the TNF alpha p55 receptor. Therefore, we conclude that TNF alpha acts as a downregulator of the SCF receptor expression.

Nitric oxide does not mediate coronary vasodilation by isoflurane

BACKGROUND

Isoflurane causes vasodilation in the coronary circulation. The current study employed a canine model permitting selective intracoronary administrations of isoflurane (1) to test the hypothesis that coronary vasodilation by isoflurane is mediated by nitric oxide and (2) to evaluate the persistence of coronary vasodilation during an extended exposure to isoflurane.

METHODS

Open-chest dogs anesthetized with fentanyl and midazolam were studied. The left anterior descending coronary artery (LAD) was perfused via extracorporeal system with normal arterial blood or with arterial blood equilibrated with 1.4% (1 MAC) isoflurane. In the LAD bed, coronary blood flow (CBF) was measured with an electromagnetic flowmeter and used to calculate myocardial oxygen consumption (MVO2). In series 1, performed at constant coronary perfusion pressure (CPP), the LAD was exposed to 3 h of isoflurane in two groups of eight dogs: control group, normal coronary endothelium; and experimental group, intracoronary infusion of the nitric oxide synthase inhibitor L-NAME (0.15 mg/min for 30 min). Series 2 was performed with CBF constant; thus, CPP varied directly with coronary vascular resistance. In this series, initial steady-state changes in CPP by isoflurane were evaluated in the same four dogs before and after L-NAME.

RESULTS

In the control group of series 1, isoflurane caused a maximal, initial increase in CBF of 444%; however, CBF decreased progressively reaching a value not significantly different from baseline after 3 h of isoflurane. Isoflurane caused a significant (approximately 35%) decrease in MVO2, which persisted during the 3-h administration. Findings after L-NAME (experimental group) were not significantly different from those in control group. In series 2, isoflurane caused significant decreases in CPP that were not affected by L-NAME.

CONCLUSIONS

The lack of effect of L-NAME on isoflurane-induced coronary vasodilation suggests that nitric oxide does not mediate this response. The increase in CBF during prolonged isoflurane waned over time, perhaps because of tachyphylaxis or emergence of a competitive vasoconstrictor mechanism, e.g., metabolic factors secondary to reduced oxygen demands.

Efficacy of recombinant human erythropoietin in the treatment of refractory anemias without excess of blasts in myelodysplastic syndromes

To determine the efficacy of recombinant human erythropoietin at pharmacological doses in myelodysplastic syndromes (MDS) without excess of blasts, 20 patients with refractory anemias (RA) or refractory anemias with ring sideroblasts (RARS) were treated in an open study with escalating doses from 40 U/kg to 300 U/kg three times a week subcutaneously during a period of 3 months. Maintenance therapy at the lowest effective dose was continued in responders. A dose response of CFU-E and BFU-E to Epo was analysed at the entry. Bone marrow examination with an in vitro study of hematopoietic progenitors was performed before and after the first three months. Seven of 20 patients responded: a total recovery was observed in 3 patients; one became transfusion independent and a reduction of 50% of the transfusion requirement was achieved in 3 others. 3 patients are still receiving treatment for 2, 3 and 4 years. No significant correlation was found between the in vitro and clinical response. A non parametric analysis of responders and non responders emphasised the importance of a long delay between the diagnosis and the treatment, (p = 0.024) and an endogenous Epo level less than 100 mU/ml (p = 0.025) in order to predict the efficacy of rhEpo. This study offers evidence that patients with refractory anemias without excess of blasts in the bone marrow respond to rhEpo at pharmacological doses. Larger studies are required in order to define the patients who may respond and to elucidate the mechanism of the positive effect of rhEpo.

Reversible inhibitory effects and absence of toxicity of the tetrapeptide acetyl-N-Ser-Asp-Lys-Pro (AcSDKP) in human long-term bone marrow culture

The effects of acetyl-N-Ser-Asp-Lys-Pro (Ac-SDKP) in human long-term bone marrow cultures (LTBMCs) were assessed by measuring the number of progenitors and the development of stromal cells over a 6-week course. In a first set of experiments, AcSDKP was added weekly at each medium change. Under these conditions, no significant effect of the peptide was observed. In contrast, by adding AcSDKP daily at 10(-10) M, the growth of the progenitors of the non-adherent (NA) compartment was inhibited by about 35%. This inhibition was entirely reversible; after stopping the addition of the peptide at the fourth week, the number of progenitors returned to control level within 2 weeks. Conversely, AcSDKP did not significantly change the number of the progenitors present in the adherent layer. In addition, AcSDKP did not affect the formation of the stromal layer nor induce the secretion of cytokines, such as tumor necrosis factor alpha (TNF-alpha), interleukin 1 beta (IL-1 beta), granulocyte colony-stimulating factor (G-CSF), interleukin 3 (IL-3), or interleukin 6 (IL-6). Our results indicate that AcSDKP has inhibitory but reversible effects on NA progenitors and does not induce long-term modifications of the microenvironment, both of particular interest for its clinical application.

Tumor necrosis factor alpha in human long-term bone marrow cultures: distinct effects on nonadherent and adherent progenitors

Although tumor necrosis factor alpha (TNF alpha) exerts a variety of activities on hematopoietic cells, suggesting it may have some potential therapeutic applications, its long-term effects on hematopoiesis are not well defined. Therefore, we took the advantage of long-term bone marrow cultures (LTBMCs) to evaluate the long-term role of TNF alpha on both the microenvironment and the hematopoietic progenitors. LTBMCs were inoculated with 100 U/ml of recombinant human TNF alpha (rhTNF alpha) either at the onset of the cultures (d0) or at day 21 (d21) when the adherent layer (AL) was already established. Then TNF alpha was added at each weekly medium change. The cellularity and the content of progenitors in both the nonadherent layer (NAL) and AL, the formation of the AL, and the presence of various cytokines in the supernatants were examined weekly. The data showed 1) a strong and durable inhibitory effect on total nonadherent cells; 2) a rapid and transient inhibition of NA progenitors, whereas adherent progenitors were lately affected; and 3) microenvironmental changes consisting of the disappearance of adipocytes and the secretion of high levels of interleukin 6. The results suggest that the inhibitory effects of TNF alpha on the NAL are in part counterbalanced by stromal modifications that in turn lead to a faster exhaustion of hematopoiesis.

Effects of butyric acid on cell cycle regulation and induction of histone H1(0) in mouse cells and tissue culture. Inducibility of H1 (0)in the late S-G2 phase of the cell cycle

We have examined the regulation of the synthesis of histone H1(0) in cultured mammalian cells treated with butyric acid. Treatment of cells with the inducer results in the arrest of synthesis of DNA and the other histones, while increasing the synthesis of H1(0) by a factor of 11. The induction of H1(0) by butyric acid occurs in a pulse with a peak at six hours, followed by a decrease to negligible levels. This pulse-like induction appears to be due to the fact that the cells are inducible for H1(0) only in the late S or G2 phases of the cell cycle. This, coupled with the fact that butyric acid blocks cells in G1, results in the burst of H1(0) synthesis after addition of the inducer. The G1 block provoked by butyric acid does not appear to result from the accumulation of H1(0). Removal of butyric acid from G1-blocked cells resulted in the resumption of cellular proliferation without prior loss of H1(0), demonstrating that the presence of this histone is not sufficient to prevent cellular proliferation.

Immunopathologic and morphologic studies of skeletal muscle in Chagas' disease

Skeletal muscle biopsies from 21 individuals infected with Trypanosoma cruzi were studied my means of immunofluorescence, ultrastructural immunochemical, light and electron microscopic, and histochemical procedures. In 12 cases, definite morphologic alterations were found. These alterations were coincident with the presence of circulating antibodies against the plasma membrane of striated muscle fibers and endothelial cells (EVI antibodies). In almost all cases the lesions also presented autologous immunoglobulins bound to the plasma membrane of muscle fibers and endothelial cells. Interstitial inflammatory exudate was not observed in the diseased muscle. On the basis of these observations, it is suggested that the EVI antibody is related to some of the pathogenetic mechanism of skeletal muscle damage in Chagas' disease.